OpenSSH 10.6 was released on 2026-10-06. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Recently the OpenSSH team have received a large number of security
bug reports, many of which are findings from AI models or made with
AI assistance. While many AI reports are determined not to have
security impact when considered in the context of a realistic
threat model, we very much welcome these reports, especially when
combined with human triage, analysis, test-cases and particularly
when accompanied by proposed fixes.
** We have seen a number of cases where a security bug identified
** by AI tools is subsequently independently discovered by a
** different researcher. This suggests that adversaries who do not
** report bugs to OSS projects are likely to be able to discover
** these bugs too. Given this, the OpenSSH team will, for now, be
** making more frequent releases to get bugfixes into users' hands
** more quickly rather than batching them until the next planned
** release.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
https://www.openssh.com/donations.html
Future deprecation notice
* scp(1): begin deprecating the -R flag, which is used to perform a
remote-to-remote copy by executing scp on a remote host. This
option is a fragile optimisation that is difficult to use because
it requires credentials on the remote host. It also creates
security risks if the shell quoting rules on the remote system
where the copy is performed differ from the client's expectations.
From OpenSSH 10.6, this option will continue to work but will
cause a deprecation warning to be emitted to standard error. In
a future release, the option will be ignored and will leave in
place the default remote-to-remote copy behaviour (copy via the
host running scp).
* sshd(8): support for platforms that do not allow file descriptor
passing and that also require root privilege for PTY allocation
will be removed in a future release. Affected platforms are known
to include SCO OpenServer 5 and QNX 6 but may include other
similarly old operating systems. This deprecation can be avoided
if the user community for these platforms is able to assist us in
building alternatives, such as avoiding the need for root in PTY
allocation.
Potentially-incompatible changes
* ssh(1), sshd(8): compression will be less effective as a result
of the change noted below in the "Security" section
* ssh(1): destination usernames entered on the commandline are now
more strictly checked and will refuse usernames that include
backslash and dollar symbols. Usernames that are specified by
the "User" directive in configuration files are not subject to
these restrictions. The motivation for this change is mentioned
below in the "Security" section.
* sshd(8): on platforms that do not support file descriptor passing
and that require root for PTY allocation, the GatewayPorts and
StreamLocalForwarding options are forcibly disabled. The
motivation for this change is discussed below in the "Security"
section.
Changes since OpenSSH 10.5
This release contains a number of security fixes, several new
features and some small bugfixes.
Security
* sftp(1): more strictly validate paths returned from the server to
avoid some cases where a server could return paths that could
manipulate a recursive copy operation into writing outside its
target directory. Report and patch from Junghoon Cho.
* sshd(8): when GSSAPIAuthentication is in use, only store GSSAPI
credentials when authentication has succeeded. Avoids a situation
where credentials from a failed GSSAPIAuthentication attempt may
persist and be made inappropriately available if another
authentication subsequently succeeds. Issue report and patch from
Moritz Theile.
* sshd(8): reset GSSAPIAuthentication before authentication, avoiding
state from one authentication attempt being confused with that of
a later attempt. Report and feedback from Moritz Theile.
* sshd(8), ssh(1): disable LZ77 dictionary coder to mitigate the
side-channel leaks described in "Crossing the Streams: SSH
Plaintext Recovery via a Common Compression Context in
Multiplexed Channels" by Fabian Bäumer and Marcus Brinkmann,
preprint https://arxiv.org/abs/2609.07709 (2026)
A chosen-plaintext attack method exists which makes use of
dictionary-based compression to recover secrets from one channel
by interacting with the SSH session's shared compression
dictionary through another channel.
Attacker-controlled input can recognizably reflect into the
total length of transmitted ciphertexts by virtue of LZ77
replacing repeated strings with back-references into the SSH
session's encoder search buffer, which is shared across all
channels. For this reason, the documentation already recommended
against enabling compression for connections that share trusted
and untrusted traffic.
This change will reduce the effectiveness of the Compression
option. Users are encouraged to use application-level compression
over the SSH protocol where possible, as this will typically be
more effective and will be completely immune to this type of
attack.
* ssh(1): disallow '$' and '\' characters in usernames entered on
the command-line to avoid usernames from untrusted sources
yielding injection in shell context via ProxyCommand, Match exec,
etc. Usernames specified via the configuration files are not
subject this this control. Reported by SecBuddyF KeenLab Tencent
(CodeBuddy Security)
We continue to recommend against directly exposing ssh(1) and
other tools' command-lines to untrusted input. Mitigations such
as this can not be absolute given the variety of shells and user
configurations in use.
* ssh-keygen(1): correct handling of Daylight Saving Time when
converting dates. Previous handling could cause errors of
up to +/- 1 hour (unless you are in the Antarctica/Troll
timezone, where the error could be +/- 2 hours). These errors
could result in creation of certificates with incorrect expiry
times. bz4004; from Khush Patel
* sshd(8), ssh(1): ensure that compressed payloads don't inflate
past the maximum supported packet length. Reported by Oleh Konko.
* sshd(8): fully honor the authorized_keys "restrict" keyword,
which was not being properly applied to tunnel forwarding
(PermitTunnel, disabled by default). This is a separate problem
to the one fixed in openssh-10.5.
* sshd(8): correctly handle some options that accept "none". Some
options, including AuthorizedPrincipalsFile, were documented as
accepting "none" as a way to disable them; however, when
overridden by an sshd_config(5) Match keyword, this argument was
being incorrectly interpreted as a literal file.
With Chris Rohlf in collaboration with Claude and Anthropic Research
* sshd(8): On OS X SDK >= 27, sandboxing is no longer supported
as the API we depended upon has been removed and no obvious
alternative provided.
* sshd(8): on platforms that do not support file descriptor passing
and that require root for PTY allocation, the post-authentication
sshd-session process retains root privilege, whereas on other
platforms this process runs with the privilege of the logged-in
user. When sshd-session was run with elevated privilege, it could
perform certain actions as root and circumvent controls that
would normally have applied to the user, such as making unix
domain socket connections or binding (via -R forwarding) to low-
numbered TCP ports.
For this reason, this release disables the GatewayPorts and
StreamLocalForwarding options and support for these (few)
platforms will be removed in future if no alternatives to
requiring privilege in the post-authentication process are found.
Affected platforms include QNX 6, SCO OpenServer 5 and builds
that were made with the --disable-fd-passing configure option.
This problem was reported separately by sn0x-sharma and by Dark
River.
New features
* All: enable hybrid post-quantum ssh-mldsa44-ed25519 signature
algorithm. Note that this no longer uses the "@openssh.com"
vendor extension suffix that the previous experimental
implementation used. Keys generated with the previous experimental
support must be regenerated and/or removed.
* sshd(8): Add the WarnWeakCrypto option to sshd_config(5). This
option was previously available for the client only. This option
is enabled by default and will log when the client uses a key
agreement scheme that is not post-quantum safe.
* ssh-keygen(1), ssh-add(1): preserve user-verification (PIN or
biometric) requirement for resident keys loaded from a FIDO
token, by checking the credential's credProtect policy.
GHPR701 from Savely Krasovsky
* ssh(1): include local and remote version strings in the ~I
connection information display.
* ssh-add(1): add a -P flag to skip PIN entry for FIDO and PKCS#11
tokens that do not require it.
* sftp(1): add '-p' flag for mkdir/lmkdir to create directories as
required. This flag has similar ergonomics to mkdir(1), and
previously-existing directories do not cause an error.
* ssh-keygen(1): add a "hexdump" key export mode that dumps the SSH
wire-formatted key blob in hex format. Useful when writing
documentation, tests, etc. E.g. `ssh-keygen -em hexdump -f /key`
* ssh(1), sshd(8): ChannelTimeout now accepts timeouts with
fractional seconds.
* sshd(8): allow specification of the location of $SSH_AUTH_SOCK
used for agent forwarding using a new AgentSocketPath option.
This supports both using a user-specific path, such as the
default of a subdirectory of $HOME ("user:.ssh/agent"), and
the previous approach of allowing agent forwarding sockets to be
located in a shared directory (e.g. "shared:/tmp"). Sockets
created in shared directories will be created inside a
subdirectory with a randomised name. bz3860
* ssh-agent(1): allow specification of agent socket directories
using a -A flag. It accepts "user:" and "shared:" directory
styles similar to the sshd AgentSocketPath option.
* sshd(8): account for public key authentication "key ok" tests
separately to auth attempts. Add a `PubkeyOptions max-pk-ok:nnnn`
option to allow a number of PK_OK tests (asking whether the
server might accept a given public key) that do not count against
MaxAuthTries, defaulting to 6 attempts. After these attempts are
exhausted, further attempts count as failed authentications
against MaxAuthTries. Practically, this allows more keys on disk
or held in ssh-agent to be checked for use before the server
disconnects.
* ssh(1), sshd(8): extend the existing TCPKeepAlive option to also
support setting keepalives on sockets created for forwarding
connections. Previously this option controlled keepalives on the
connection socket only. TCPKeepAlive "yes" or "transport" enables
keepalives on the connection socket. "TCPKeepAlive all" additionally
enables them for forwarding sockets. bz3921
Bugfixes
* sshd(8), ssh(1): fix configuration matching on more Turkic
languages which have disjoint dotted and dotless i/I characters,
specifically Azerbaijani and Crimean Tatar. bz3991
* ssh(1), sshd(8): don't attempt to set TCP_NODELAY on non-IP/IPv6
sockets. Eliminates some noise in debug logs.
* ssh(1): fix case for ssh -G option output; bz4005
* ssh(1), sshd(8): Fix ChannelTimeout specificity; previously a
more specific channel type (e.g. "session:shell") could clobber
a user-specified ChannelTimeout if it was less specific (e.g.
"session"). Also, in some cases, the debug messages were
printing 0 instead of the effective timeout. bz3994
* sftp(1): avoid NULL dereference crash in some circumstances when
a server fails a stat/lstat operation. GHPR707
* sshd(8): close a race condition where a SIGTERM/SIGQUIT would be
ignored if it was received by the server while it was processing a
SIGHUP restart request. bz3981
* sshd(8), ssh(1): check key and CA signature types during key
parsing against allowlists (PubkeyAcceptedAlgorithms, etc) as
early as possible. This reduces the attack surface presented by
disabled algorithms. Suggested by and with extensive feedback
from Chris Rohlf in collaboration with Claude and Anthropic
Research.
* All: switch the fallback implementation of the ed25519 signature
algorithm used when libcrypto is disabled from SUPERCOP ed25519
to libsodium. The libsodium implementation includes a number of
strictness checks over the original reference implementation we
have used to this point and a more ergonomic API.
* ssh-add(1), ssh(1), ssh-keygen(1): fix spin on password entry when
the program attempting to read a password was started in a
background process group, with no TTY and with certain signals
ignored. bz3995
* scp(1): disallow nul byte in received scp -O filename. This was
not reachable in normal operation. Reported by Chua Wei Xun.
* ssh-keygen(1), ssh(1), sshd(8): implement a maximum number of KDF
rounds that will be accepted when writing an OpenSSH-format
private key or when loading one. This limit is set quite high
(1M), but ensures that a service that is passed a bad key with a
ridiculously high number of rounds will eventually complete
parsing it.
* ssh-keygen(1): bump the default number of KDF rounds from 24 to
32 (this is a linear increase, not like bcrypt(3) which is
exponential).
* ssh(1): make StreamLocalBindMask properly respect Host/Match
blocks and make it first-match-wins as documented. bz4013
* sshd(8): make StreamLocalBindMask properly first-match-wins.
Portability
* All: remove the NetBSD BROKEN_READ_COMPARISON workaround. This
appears to be no longer required and caused pre-auth CPU spinning.
* sshd(8): don't link sshd against libselinux when SELinux support
is enabled (note: this library is still linked for the sshd-auth
and sshd-session helper binaries).
* sshd(8): allow madvise(..., MADV_DONTNEED_LOCKED) in the seccomp
sandbox; needed by GrapheneOS' hardened allocator. bz4001
* sshd(8): restrict mremap(2) flags accepted by the seccomp
sandbox. Only MREMAP_MAYMOVE is now accepted as other flags may
have some utility in attack chains. Reported by: Mohammad Hossein
Abedini.
* sshd(8): allow PAMServiceName in Match (regressed in 10.4).
During the refactor of server option parsing, the ability to set
PAMServiceName in Match blocks was accidentally disabled.
* sshd(8): the --disable-fd-passing configure option has been
removed.
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available from the mirror sites:
https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/RELEASE_KEY.asc
Reporting Bugs:
OpenSSH 10.5 was released on 2026-08-11. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Recently the OpenSSH team have received a large number of security
bug reports, many of which are findings from AI models or made with
AI assistance. While many AI reports are determined not to have
security impact when considered in the context of a realistic
threat model, we very much welcome these reports, especially when
combined with human triage, analysis, test-cases and particularly
when accompanied by proposed fixes.
We have seen a number of cases where a security bug identified by
AI tools is subsequently independently discovered by a different
researcher. This suggests that adversaries who do not report bugs
to OSS projects are likely to be able to discover these bugs too.
Given this, the OpenSSH team will, for now, be making more frequent
releases to get bugfixes into users' hands more quickly rather than
batching them until the next planned release.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
https://www.openssh.com/donations.html
Potentially-incompatible changes
* Portable OpenSSH now requires ECC (Elliptic Curve Cryptography)
support in libcrypto, including support for the NISTP521 curve.
ECC is included in the default build configurations of all
versions of all libcrypto implementations currently supported by
OpenSSH, including LibreSSL, OpenSSL, BoringSSL and AWS LC.
The --without-openssl build configuration is not affected.
Changes since OpenSSH 10.4
This release contains a number of security fixes and small bugfixes.
Security
* ssh-agent(1): fix an interaction between agent locking and the
session-bind@openssh.com extension that is used to identify
forwarded agents. These binding requests were refused when the
agent was locked, with the result that operations that were
intended to be limited to local use only could be performed
remotely, including the ability to add PKCS#11 tokens and make
use of keys that had destination restrictions applied.
Reported by sn0x-sharma
* ssh(1): avoid potential realloc use-after-free in the client if a
remote forwarding is added via the local session multiplexing
socket while a remote forwarding open request is pending with the
server. Report and fix from Brian Mingus of Cognatory
* sshd(8): make the authorized_keys "restrict" keyword apply
correctly to tunnel forwarding too (which is administratively
disabled by default). Reported by Erichen, Institute of Computing
Technology, Chinese Academy of Sciences
New features
* ssh-keygen(1): add ability to set or clear the touch-required and
verify-required flags on FIDO private keys when resetting a
private key's passphrase.
* ssh(1): tweak ordering of certificates tried during pubkey
authentication to prefer FIDO keys that do not require user
presence (touch) first, and FIDO keys that require user
verification via PIN or biometrics last. This effectively tries
low-friction authenticators before higher friction ones.
* ssh(1): add a "ssh -Z user@host" mode that prints the keys that
will be tried for public key authentication in the order that
they will be used.
* sshd(8) use setproctitle(3) to identify sshd-session when its
acting as a post-authentication monitor.
Bugfixes
* ssh-keyscan(1): make reading the server banner a non-blocking
operation to prevent a stuck server from blocking a many-host
keyscan from proceeding.
* sshd(8): use sshpkt_fatal() instead of plain fatal() for errors
in the packet code as this provides context of the failing peer
(address, port, user, etc).
* sshd(8): when signing hostkey proofs for a client UpdateHostKeys
request, allow each hostkey to perform at most one signature
operation.
* sshd(8) fix GSSAPI option names, that were broken during a
servconf.c refactoring in openssh-10.4; bz3974.
* ssh-keygen(1): pass back errors from ed25519 key generation, which
theoretically can fail. GHPR702.
* sshd(8): move check of public key type against allowed algorithms
to before parsing of the key sent by the peer. This removes at
least some key parsing and verification paths from the pre-auth
attack surface. Suggested by Christopher Paul Rohlf of Anthropic.
* ssh-keygen(1): fix double frees (impossible to reach outside of a
test harness), and also use freezero where possible. From
Christopher Paul Rohlf at Anthropic.
* sshd(8): fix ChannelTimeout and RekeyLimit not being applied in
sshd_config Match blocks.
* sshd(8): in sshd config dump mode, write all directives in mixed
case for consistency
Portability
* sshd(8): re-allow PAMServiceName inside a Match block, which
was incorrectly disabled during a refactoring in openssh-10.4.
bz3987
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available from the mirror sites:
https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/RELEASE_KEY.asc
Reporting Bugs:
OpenSSH 10.4 was released on 2026-07-06. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
https://www.openssh.com/donations.html
Potentially-incompatible changes
* sshd(8): configuration dump mode ("sshd -G") now writes directives
in mixed case (e.g. "PubkeyAuthentication") whereas previously it
emitted only lower-case names.
* sshd(8): on Linux systems with the seccomp sandbox enabled,
failures to enable SECCOMP or NO_NEW_PRIVS are now fatal.
Previously sshd(8) would log the error but continue operation,
to support systems that lacked these features. Now systems that
lack these should instead disable the sandbox at configure time.
* ssh(1), sshd(8): make the transport protocol stricter by
disconnecting if the peer sends non-KEX messages during a post-
authentication key re-exchange. Previously a malicious peer could
continue sending non-key exchange messages without penalty. These
would be buffered, causing memory to be wasted up until the
connection terminated or the server/client hit a memory limit.
Implementations that do not restrict messages sent during key
exchange as per RFC4253 section 7.1 may be disconnected.
Reported by Marko Jevtic.
Changes since OpenSSH 10.3
This release contains a number of security fixes as well as general
bugfixes and a couple of new features.
Security
* sftp(1): when downloading files on the command-line using
"sftp host:/path .", a malicious server could cause the file to
be downloaded to an unexpected location. This issue was identified
by the Swival Security Scanner.
* scp(1): when copying files between two remote destinations, do
not allow a malicious server to write files to the parent
directory of the intended target directory. This issue was
identified by the Swival Security Scanner.
* sshd(8): when using the "internal-sftp" SFTP server implementation
(this is not the default), long command lines were previously
truncated silently after the 9th argument. If a security-relevant
option was in the 10th or later position, it would be discarded.
Reported by Steve Caffrey.
* sshd(8): add a documentation note to mention that the
GSSAPIStrictAcceptorCheck option is ineffective when the server
is joined to a Windows Active Directory. Reported by Yarin Aharoni
of Safebreach.
* sshd(8): DisableForwarding=yes didn't override PermitTunnel=yes
as it was documented to do. Note that PermitTunnel is not enabled
by default. Reported independently by Huzaifa Sidhpurwala of
Redhat and Marko Jevtic.
* sshd(8): avoid a potential pre-authentication denial of service
when GSSAPIAuthentication was enabled (this feature is off by
default). This was not mitigated by MaxAuthTries, but would be
penalised by PerSourcePenalties. This was reported by Manfred
Kaiser of the milCERT AT (Austrian Ministry of Defence).
* sshd(8): fix a number of cases where the minimum authentication
delay was not being enforced. Reported by the Orange Cyberdefense
Vulnerability Team.
* ssh(1): fix a possible client-side use-after-free if the server
changes its host key during a key reexchange. This was reported by
Zhenpeng (Leo) Lin of Depthfirst.
New features
* All: add experimental support for a composite post-quantum
signature scheme that combines ML-DSA 44 and Ed25519 as specified
in draft-miller-sshm-mldsa44-ed25519-composite-sigs.
This scheme is not enabled by default. To use it, you'll need
to add it to HostKeyAlgorithms, PubkeyAcceptedAlgorithms, etc.
Keys may be generated using "ssh-keygen -t mldsa44-ed25519".
* ssh(1), sshd(8): replace the wildcard pattern matcher with an
implementation based on an NFA. This avoids exponential worst-case
behaviour for the old implementation.
Bugfixes
* ssh-agent(1): fix incorrect reply to "query" SSH_AGENTC_EXTENSION
requests. bz3967
* sshd(8): avoid sending observably different messages for valid vs
invalid users in GSSAPIAuthentication (disabled by default).
* ssh(1), sshd(8): fix several bugs that incorrectly
classified bulk traffic as interactive. bz3972, bz3958
* ssh-keygen(1), ssh-add(1): skip unsupported key types when
downloading resident keys from a FIDO token. Previously, downloads
would abort when one was encountered. GHPR657
* ssh(1): fix a potential use-after-free on an error path if
cipher_init() fails.
* sshd(8): perform stricter encoding and validation of transport
state passed between sshd privilege separation subprocesses. This
somewhat further hardens the server against attacks on sshd-auth
or sshd-session subprocesses.
* ssh-agent(1): avoid possible runtime denial of service by
enforcing some limits on the length of usernames in key use
constraints.
* sftp(1): fix two separate one-byte out-of-bounds reads, in
SSH2_FXP_REALPATH and batch command processing.
* sftp-server(8): disallow use of the copy-data extension to read
and write to the same inode simultaneously.
* ssh(1), sshd(8): avoid strlen(NULL) crash if an X11 channel was
created before the x11-req SSH_MSG_CHANNEL_REQUEST was sent.
GHPR679
* sftp(1), scp(1): avoid a situation where sftp_download() could get
stuck in a loop if a broken server repeatedly returned zero length
while reading a file.
* ssh(1): avoid leaking DNS0x20 case-randomised names into names
canonicalised using CanonicalizePermittedCNAMEs. bz3966
* sftp-server(8): avoid truncation of pathnames passed to lstat()
during SSH_FXP_REALPATH handling on systems where PATH_MAX is not
the actual max. GHPR688
* ssh(1), sshd(8): correct arming of poll(2) event masks for some
socket-type channels. GHPR660
* sshd(8): major refactor of sshd_config parsing and management
code, to allow for more exact serialisation/deserialisation across
privilege separation boundaries.
* ssh-add(1): open connection to the agent only after getopt()
processing has completed, to give options like "-v" a chance to
display debug information about this operation.
* crypto code: fix bounds checking when signing messages of length
greater than will fit in a size_t. In OpenSSH, message sizes are
bounded by SSHBUF_SIZE_MAX so this was unreachable.
* crypto code: add signature malleability and pubkey validity checks
to ed25519 verification. SSH doesn't depend on these properties
* crypto code: fix ECDSA order check for curves with cofactor != 1.
All supported EC curves have cofactor 1, so this was
unreachable.
* sshd(8): differentiate between execution failures and a subsystem
that was not found when logging why a subsystem failed to start.
GHPR637
* All: use safer idioms for timegm(3) and mktime(3) error detection.
* ssh(1), sshd(8): avoid accepting invalid cipher or MAC lists in
config files or command-line arguments. This could cause runtime
failures later.
* ssh(1): fix NULL deref crash during pubkey auth when using a PEM
style private key with no corresponding .pub key adjacent to it.
* sshd(8): don't print an error message when trying to load a host
private key when PKCS#11 keys are in use, as these don't need the
private half on the filesystem. GHPR664
* All: don't use deprecated ERR_load_crypto_strings(). GHPR650
* ssh(1): properly report errors during configuration default
setting. GHPR649
* ssh(1): use correct directive name (Match instead of Host) in
error message. bz3968
* sftp(1): fix "ls -ln" which was not correctly showing numeric
UID/GIDs but rather user and group names. bz3953
* sshd(8): avoid possible NULL dereference if an allocation fails
during config parsing. bz3948
* All: fix ineffective guards against loading overly large public
keys in several places. bz3969 and bz3970
* sftp(1): ensure file descriptors used by sftp to communicate to
its ssh(1) subprocess don't leak into executed subprocesses (e.g.
via "!"). GHPR693
Portability
* Sync fmt_scaled.c with OpenBSD upstream, picking up an exactness
fix for large exponents (GHPR671)
* sshd(8): remove duplicate sandbox entry for clock_gettime64.
* ssh(1), sshd(8): use correct IPTOS_DSCP_VA value if not provided
by the system headers.
* Sync getrrsetbyname.c with OpenBSD upstream, picking up robustness
fixes.
* Disable replacements in openbsd-compat for strvisx(3) and
stravis(3), as these are unused in OpenSSH
* Avoid fortify warnings on Android bz3954
* Fix a number of memory leaks on error paths in the portability
code. GHPR681
* Revise the README.privsep documentation to reflect sshd's recent
switch to a multi-binary model.
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available from the mirror sites:
https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/RELEASE_KEY.asc
Reporting Bugs:
OpenSSH 10.3 was released on 2026-04-02. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
https://www.openssh.com/donations.html
Potentially-incompatible changes
* ssh(1), sshd(8): remove bug compatibility for implementations
that don't support rekeying. If such an implementation tries to
interoperate with OpenSSH, it will now eventually fail when the
transport needs rekeying.
* sshd(8): prior to this release, a certificate that had an empty
principals section would be treated as matching any principal
(i.e. as a wildcard) when used via authorized_keys principals=""
option. This was intentional, but created a surprising and
potentially risky situation if a CA accidentally issued a
certificate with an empty principals section: instead of being
useless as one might expect, it could be used to authenticate as
any user who trusted the CA via authorized_keys. [Note that this
condition did not apply to CAs trusted via the sshd_config(5)
TrustedUserCAKeys option.]
This release treats an empty principals section as never matching
any principal, and also fixes interpretation of wildcard
characters in certificate principals. Now they are consistently
implemented for host certificates and not supported for user
certificates.
* ssh(1): the -J and equivalent -oProxyJump="..." options now
validate user and host names for ProxyJump/-J options passed
via the command-line (no such validation is performed for this
option in configuration files). This prevents shell injection in
situations where these were directly exposed to adversarial
input, which would have been a terrible idea to begin with.
Reported by rabbit.
Changes since OpenSSH 10.2
This release contains some relatively minor security fixes as well
as a number of feature improvements and general bugfixes.
Security
* ssh(1): validation of shell metacharacters in user names supplied
on the command-line was performed too late to prevent some
situations where they could be expanded from %-tokens in
ssh_config. For certain configurations, such as those that use a
"%u" token in a "Match exec" block, an attacker who can control
the user name passed to ssh(1) could potentially execute arbitrary
shell commands. Reported by Florian Kohnhäuser.
We continue to recommend against directly exposing ssh(1) and
other tools' command-lines to untrusted input. Mitigations such
as this can not be absolute given the variety of shells and user
configurations in use.
* sshd(8): when matching an authorized_keys principals="" option
against a list of principals in a certificate, an incorrect
algorithm was used that could allow inappropriate matching in
cases where a principal name in the certificate contains a
comma character. Exploitation of the condition requires an
authorized_keys principals="" option that lists more than one
principal *and* a CA that will issue a certificate that encodes
more than one of these principal names separated by a comma
(typical CAs strongly constrain which principal names they will
place in a certificate). This condition only applies to user-
trusted CA keys in authorized_keys, the main certificate
authentication path (TrustedUserCAKeys/AuthorizedPrincipalsFile)
is not affected. Reported by Vladimir Tokarev.
* scp(1): when downloading files as root in legacy (-O) mode and
without the -p (preserve modes) flag set, scp did not clear
setuid/setgid bits from downloaded files as one might typically
expect. This bug dates back to the original Berkeley rcp program.
Reported by Christos Papakonstantinou of Cantina and Spearbit.
* sshd(8): fix incomplete application of PubkeyAcceptedAlgorithms
and HostbasedAcceptedAlgorithms with regard to ECDSA keys.
Previously if one of these directives contains any ECDSA algorithm
name (say "ecdsa-sha2-nistp384"), then any other ECDSA algorithm
would be accepted in its place regardless of whether it was
listed or not. Reported by Christos Papakonstantinou of Cantina
and Spearbit.
* ssh(1): connection multiplexing confirmation (requested using
"ControlMaster ask/autoask") was not being tested for proxy mode
multiplexing sessions (i.e. "ssh -O proxy ..."). Reported by
Michalis Vasileiadis.
New features
* ssh(1), sshd(8): support IANA-assigned codepoints for SSH agent
forwarding, as per draft-ietf-sshm-ssh-agent. Support for the new
names is advertised via the EXT_INFO message. If a server offers
support for the new names, then they are used preferentially.
Support for the pre-standardisation "@openssh.com" extensions for
agent forwarding remains supported.
* ssh-agent(1): implement support for draft-ietf-sshm-ssh-agent
"query" extension.
* ssh-add(1): support querying the protocol extensions via the
agent "query" extension with a new -Q flag.
* ssh(1): support multiple files in a ssh_config RevokedHostKeys
directive. bz3918
* sshd(8): support multiple files in a sshd_config RevokedKeys
directive bz3918
* ssh(1): add a ~I escape option that shows information about the
current SSH connection.
* ssh(1): add an "ssh -Oconninfo user@host" multiplexing command
that shows connection information, similar to the ~I escapechar.
* ssh(1): add an "ssh -O channels user@host" multiplexing command to
get a running mux process to show information about what channels
are currently open.
* sshd(8): add 'invaliduser' penalty to PerSourcePenalties, which is
applied to login attempts for usernames that do not match real
accounts. Defaults to 5s to match 'authfail' but allows
administrators to block such attempts for longer if desired.
* sshd(8): add a GSSAPIDelegateCredentials option for the server,
controlling whether it accepts delegated credentials offered by
the client. This option mirrors the same option in ssh_config.
GHPR614
* ssh(1), sshd(8): support the VA DSCP codepoint in the IPQoS
directive.
* sshd(8): convert PerSourcePenalties to using floating point time,
allowing penalties to be less than a second. This is useful if you
need to penalise things you expect to occur at >=1 QPS.
* ssh-keygen(1): support writing ED25519 keys in PKCS8 format.
GHPR570
* Support the ed25519 signature scheme via libcrypto.
Bugfixes
* sshd(8): make IPQoS first-match-wins in sshd_config, like other
configuration directives. bz3924
* sshd(8): fix potential crash when MaxStartups is using a single
argument (i.e. not using the MaxStartps x:y:z form) to a value
below 10. bz3941
* sshd(8): fix a potential hang during key exchange if needed DH
group values were missing from /etc/moduli.
* ssh-agent(1): fix return values from extensions to be correct wrt
draft-ietf-sshm-ssh-agent: extension requests should indicate
failure using SSH_AGENT_EXTENSION_FAILURE rather than the generic
SSH_AGENT_FAILURE error code. This allows the client to discern
between "the request failed" and "the agent doesn't support this
extension".
* ssh(1): use fmprintf for showing challenge-response name and info
to preserve UTF-8 characters where appropriate. Prompted by GitHub
PR#452.
* scp(1): when uploading a directory using sftp/sftp (e.g. during a
recursive transfer), don't clobber the remote directory
permissions unless either we created the directory during the
transfer or the -p flag was set. bz3925
* All: implement missing pieces of FIDO/webauthn signature support,
mostly related to certificate handling and enable acceptance of this
signature format by default. bz3748 GHPR624 GHPR625
* sshd_config(5): make it clear that DenyUsers/DenyGroups overrides
AllowUsers/AllowGroups. Previously we specified the order in which
the directives are processed but it was ambiguous as to what
happened if both matched.
* ssh(1): don't try to match certificates held in an agent to
private keys. This matching is done to support certificates that
were loaded without their private key material, but is
unnecessary for agent-hosted certificate which always have
private key material available in the agent. Worse, this matching
would mess up the request sent to the agent in such a way as to
break usage of these keys when the key usage was restricted in
the agent. bz3752
* sftp(1): if editline has been switched to vi mode (i.e. via "bind
-v" in .editrc), setup a keybinding so that command mode can be
entered.
* ssh(1), sshd(8): improve performance of keying the sntrup761 key
agreement algorithm.
* ssh(1), sshd(8): enforce maximum packet/block limit during
pre-authentication phase.
* sftp(1): don't misuse the sftp limits extension's open-handles
field. This value is supposed to be the number of handles a
server will allow to be opened and not a number of outstanding
read/write requests that can be sent during an upload/download.
* sshd(8): don't crash at connection time if the main sshd_config
lacks any subsystem directive but one is defined in a Match block.
bz3906
* sshd_config(5): add a warning next to the ForceCommand directive
that forcing a command doesn't automatically disable forwarding.
* sshd_config(5): add a warning that TOKENS are replaced without
filtering or escaping and that it's the administrator's
responsibility to ensure they are used safely in context.
* scp(1): correctly quote filenames in verbose output for local->
local copies. bz3900
* sshd(8): don't mess up the PerSourceNetBlockSize IPv6 mask if
sscanf didn't decode it. GHPR598
* ssh-add(1): when loading FIDO2 resident keys, set the comment to
the FIDO application string. This matches the behaviour of
ssh-keygen -K. GHPR608
* sshd(8): don't strnvis() log messages that are going to be logged
by sshd-auth via its parent sshd-session process, as the parent
will also run them though strnvis(). Prevents double-escaping of
non-printing characters in some log messages. bz3896
* ssh-agent(1): escape SSH_AUTH_SOCK paths that are sent to the
shell as setenv commands. Unbreaks ssh-agent for home directory
paths that contain whitespace. bz3884
* All: Remove unnecessary checks for ECDSA public key validity.
* sshd(8): activate UnusedConnectionTimeout only after the last
channel has closed. Previously UnusedConnectionTimeout could fire
early after a ChannelTimeout. This was not a problem for the
OpenSSH client because it terminates once all channels have
closed but could cause problems for other clients (e.g. API
clients) that do things differently. bz3827
* All: fix PKCS#11 key PIN entry problems introduced in
openssh-10.1/10.2. bz3879
* scp(1): when using the SFTP protocol for transfers, fix implicit
destination path selection when source path ends with "..". bz3871
* sftp(1): when tab-completing a filename, ensure that the completed
string does not end up mid-way through a multibyte character, as
this will cause a fatal() later on. GHPR#587
* ssh-keygen(1): fix crash at exit (visible via ssh-keygen -D) when
multiple keys loaded.
* scp(1)/sftp(1): correctly display bandwidths >2GBps in the
progress meter.
Portability
* sshd(8): fix condition introduced in openssh 10.2p1 stable branch
here a PAM module that changed the requested username between
SSH_MSG_USERAUTH_REQUEST messages during authentication could
confuse the PAM stack and let it proceed with a different
understanding of the active username than the rest of sshd.
Reported by Mike Damm.
* sshd(8): immediately report interactive instructions to clients
when using keyboard-interactive authentication with PAM. bz2876
* sshd(8): fix duplicate PAM messages under some situations.
* sshd(8): don't leak PAM handle on repeat invocations. bz3882
* All: support linking libcrypto implementations (e.g. BoringSSL)
that require libstdc++.
* sshd(8): fix ut_type for btmp records, correctly using
LOGIN_PROCESS and USER_PROCESS.
* sshd(8): allow uname(3) in the seccomp sandbox. This is needed by
zlib-ng on RISC-V platforms.
* All: remove remaining OpenSSL_add_all_algorithms() calls.
We already have OPENSSL_init_crypto() in the compat layer.
Prompted by github PR#606
* All: fix builds on older Mac OS wrt nfds_t.
* mdoc2man: several improvements including better support for Dl
and Ns inside Ic.
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available from the mirror sites:
https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/RELEASE_KEY.asc
Reporting Bugs:
OpenSSH 10.2 was released on 2025-10-10. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
https://www.openssh.com/donations.html
Future deprecation warning
* A future release of OpenSSH will deprecate support for SHA1 SSHFP
records due to weaknesses in the SHA1 hash function. SHA1 SSHFP
DNS records will be ignored and ssh-keygen -r will generate only
SHA256 SSHFP records.
The SHA256 hash algorithm, which has no known weaknesses, has
been supported for SSHFP records since OpenSSH 6.1, released in
2012.
Changes since OpenSSH 10.1
This is a bugfix release, primarily to fix a problem that rendered
ssh(1) unusable when ControlPersist was enabled.
Bugfixes
* ssh(1): fix mishandling of terminal connections when
ControlPersist was active that rendered the session unusable.
bz3872
* ssh-keygen(1): fix download of keys from PKCS#11 tokens.
* ssh-keygen(1): fix CA signing operations when the CA key is held
in a ssh-agent(1). bz3877
Portability
* All: support platforms without mmap(2), e.g. WASM builds such as
https://hterm.org
* All: fix builds on FreeBSD for missing fnctl.h include.
* All: fix builds on MacOS <10.12 Sierra, which lacks
clock_gettime(3)
* sshd(8): don't PAM_RHOST if the remote host is the "UNKNOWN"
placeholder name. Avoids potential hangs in some PAM modules as
they try to resolve it. Note, sshd(8) only uses the "UNKNOWN"
name when the connection is not on an IPv4 or IPv6 socket.
Checksums:
SHA1 (openssh-10.2.tar.gz) = 6fcda8004bad0fb0eaee60e8308f91b605ad0dce
SHA256 (openssh-10.2.tar.gz) = y0rCEdrVc4OJRZLg0u3F0frAgz87ydeTktCk3rQfVj8=
SHA1 (openssh-10.2p1.tar.gz) = c34efade16109f065ec8c834f237bcedd8d7ef5c
SHA256 (openssh-10.2p1.tar.gz) = zMQsBBmTeVkmP6Hb0W2vwYxWuYTANWLSk3zlamD3mLI=
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available from the mirror sites:
https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/RELEASE_KEY.asc
Reporting Bugs:
OpenSSH 10.1 was released on 2025-10-06. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
https://www.openssh.com/donations.html
Future deprecation warning
* A future release of OpenSSH will deprecate support for SHA1 SSHFP
records due to weaknesses in the SHA1 hash function. SHA1 SSHFP
DNS records will be ignored and ssh-keygen -r will generate only
SHA256 SSHFP records.
The SHA256 hash algorithm, which has no known weaknesses, has
been supported for SSHFP records since OpenSSH 6.1, released in
2012.
Potentially-incompatible changes
* ssh(1): add a warning when the connection negotiates a non-post
quantum key agreement algorithm.
This warning has been added due to the risk of "store now, decrypt
later" attacks. More details at https://openssh.com/pq.html
This warning may be controlled via a new WarnWeakCrypto ssh_config
option, defaulting to on. This option is likely to control
additional weak crypto warnings in the future.
* ssh(1), sshd(8): major changes to handling of DSCP marking/IPQoS
In both client and server the default DSCP (a.k.a IPQoS) values
were revised and the way these values are used during runtime has
changed.
Interactive traffic is now assigned to the EF (Expedited
Forwarding) class by default. This provides more appropriate
packet prioritisation information for the intermediate network,
such as wireless media (cf. RFC 8325). Non-interactive traffic
will now use the operating system default DSCP marking. Both the
interactive and non-interactive DSCP values may be overridden via
the IPQoS keyword, described in ssh_config(5) and sshd_config(5).
The appropriate DSCP marking is now automatically selected and
updated as needed over the course of a connection's lifetime.
ssh(1) and sshd(8) will switch between the interactive and
non-interactive IPQoS values depending on the type of SSH
channels open at the time. For example, if an sftp session is
using the connection alongside a shell session, then the non-
interactive value will be used for the duration of the sftp. A
connection which contains only interactive sessions is marked EF.
* ssh(1), sshd(8): deprecate support for IPv4 type-of-service (ToS)
keywords in the IPQoS configuration directive.
Type of Service (ToS) was deprecated in the late nineties and
replaced with the Differentiated Services architecture, which
has significant advantages for operators because it offers more
granularity.
OpenSSH switched its default IPQoS from ToS to DSCP values in
2018 (openssh-7.7).
IPQoS configurations with 'lowdelay', 'reliability', or
'throughput' will be ignored and will instead use the system
default QoS settings. Additionally, a debug message will be logged
about the deprecation with a suggestion to use DSCP QoS instead.
* ssh-add(1): when adding certificates to an agent, set the expiry
to the certificate expiry time plus a short (5 min) grace period.
This will cause the agent to automatically remove certificates
shortly after they expire. A new ssh-add -N option disables this
behaviour.
* All: remove experimental support for XMSS keys. This was never
enabled by default. We expect to implement a new post-quantum
signature scheme in the near future.
* ssh-agent(1), sshd(8): move agent listener sockets from /tmp to
under ~/.ssh/agent for both ssh-agent(1) and forwarded sockets
in sshd(8).
This ensures processes that have restricted filesystem access
that includes /tmp do not ambiently have the ability to use keys
in an agent.
Moving the default directory has the consequence that the OS will
no longer clean up stale agent sockets, so ssh-agent now gains
this ability.
To support $HOME on NFS, the socket path includes a truncated
hash of the hostname. ssh-agent will, by default, only clean up
sockets from the same hostname.
ssh-agent(1) gains some new flags: -U suppresses the automatic
cleanup of stale sockets when it starts. -u forces a cleanup
without keeping a running agent, -uu forces a cleanup that ignores
the hostname. -T makes ssh-agent put the socket back in /tmp.
Changes since OpenSSH 10.0
This release contains a minor security fix as well as a number of
feature improvements and bugfixes.
Security
* ssh(1): disallow control characters in usernames passed via the
commandline or expanded using %-sequences from the configuration
file, and disallow \0 characters in ssh:// URIs.
If an ssh(1) commandline was constructed using usernames or URIs
obtained from an untrusted source, and if a ProxyCommand that uses
the %r expansion was configured, then it may be possible for an
attacker to inject shell expressions that may be executed when the
proxy command is started.
We strongly recommend against using untrusted inputs to construct
ssh(1) commandlines.
This change also relaxes the validity checks in one small way:
usernames supplied via the configuration file as literals (i.e.
that have no % expansion characters) are not subject to these
validity checks. This allows usernames that contain arbitrary
characters to be used, but only via configuration files. This is
done on the basis that ssh's configuration is trusted.
This issue was reported by David Leadbeater.
New features
* ssh(1), sshd(8): add SIGINFO handlers to log active channel and
session information.
* sshd(8): when refusing a certificate for user authentication, log
enough information to identify the certificate in addition to the
reason why it was being denied. Makes debugging certificate
authorisation problems a bit easier.
* ssh(1), ssh-agent(1): support ed25519 keys hosted on PKCS#11
tokens.
* ssh(1): add an ssh_config(5) RefuseConnection option that, when
encountered while processing an active section in a
configuration, terminates ssh(1) with an error message that
contains the argument to the option.
This may be useful for expressing reminders or warnings in config
files, for example:
Match host foo
RefuseConnection "foo is deprecated, use splork instead"
* sshd(8): make the X11 display number check relative to
X11DisplayOffset. This will allow people to use X11DisplayOffset
to configure much higher port ranges if they really want, while
not changing the default behaviour.
* unit tests: the unit test framework now includes some basic
benchmarking capabilities. Run with "make UNITTEST_BENCHMARK=yes"
on OpenBSD or "make unit-bench" on Portable OpenSSH.
Bugfixes
* sshd(8): fix mistracking of MaxStartups process exits in some
situations. At worst, this could cause all MaxStartups slots to
fill and sshd to refuse new connections.
* ssh(1): fix delay on X client startup when ObscureKeystrokeTiming
is enabled. bz#3820
* sshd(8): increase the maximum size of the supported configuration
from 256KB to 4MB, which ought to be enough for anybody. Fail
early and visibly when this limit is breached. bz3808
* sftp(1): during sftp uploads, avoid a condition where a failed
write could be ignored if a subsequent write succeeded. This is
unlikely but technically possible because sftp servers are
allowed to reorder requests.
* sshd(8): avoid a race condition when the sshd-auth process exits
that could cause a spurious error message to be logged.
* sshd(8): log at level INFO when PerSourcePenalties actually
blocks access to a source address range. Previously this was
logged at level VERBOSE, which hid enforcement actions under
default config settings.
* sshd(8): GssStrictAcceptor was missing from sshd -T output; fix
* sshd(8): Make the MaxStartups and PerSourceNetBlockSize options
first-match-wins as advertised. bz3859
* ssh(1): fix an incorrect return value check in the local forward
cancellation path that would cause failed cancellations not to be
logged.
* sshd(8): make "Match !final" not trigger a second parsing pass
of ssh_config (unless hostname canonicalisation or a separate
"Match final" does). bz3843
* ssh(1): better debug diagnostics when loading keys. Will now list
key fingerprint and algorithm (not just algorithm number) as well
as making it explicit which keys didn't load.
* All: fix a number of memory leaks found by LeakSanitizer,
Coverity and manual inspection.
* sshd(8): Output the current name for PermitRootLogin's
"prohibit-password" in sshd -T instead of its deprecated alias
"without-password". bz#3788
* ssh(1): make writing known_hosts lines more atomic by writing
the entire line in one operation and using unbuffered stdio.
Usually writes to this file are serialised on the "Are you sure
you want to continue connecting?" prompt, but if host key
checking is disabled and connections were being made with high
concurrency then interleaved writes might have been possible.
Portability
* sshd(8): check the username didn't change during the PAM
transactions.
PAM modules can change the user during their execution, but
this is not supported by sshd(8). If such a case was incorrectly
configured by the system administrator, then sshd(8) could end up
using a different username to the one authorised by PAM.
* sshd(8): don't log audit messages with UNKNOWN hostname to avoid
slow DNS lookups in the audit subsystem.
* All: when making a copy of struct passwd, ensure struct fields are
non-NULL. Android libc can return NULL pw_gecos, for example.
* All: Remove status bits from OpenSSL >=3 version check.
* sshd(8), ssh(1): Use SSH_TUN_COMPAT_AF on FreeBSD. Otherwise tun
forwarding from other OSes fails as soon as the first IPv6 message
is sent by the other side (which is usually a Router Solicitation
ICMPv6 message which is sent as soon as the interface is up).
* ssh(1), ssh-agent(8): check for nlist function presence before
attempting to use it instead of relying on the presence of the
nlist.h header. Mac OS X, for example, has the header but not
the function in the 64bit libraries.
* All: fill in missing system header files.
Create replacement header files inside openbsd-compat for common
headers that are missing on a given platform. Usually these are
just empty, but in some cases they'll include the equivalent file.
This avoids having to wrap those includes in '#ifdef HAVE_FOO_H'
and reduces the diff between Portable OpenSSH and OpenBSD.
* sshd(8): handle futex_time64 properly in seccomp sandbox
Previously we only allowed __NR_futex, but some 32-bit systems
apparently support __NR_futex_time64. We had support for this
in the sandbox, but because of a macro error only __NR_futex was
allowlisted.
* Add contrib/gnome-ssh-askpass4 for GNOME 40+ using the GCR API.
* sshd(8): let ga_init() fail gracefully if getgrouplist does.
Apparently getgrouplist() can fail on OSX when passed a
non-existent group name. Other platforms seem to return a group
list consisting of the numeric gid passed to the function. bz3848
* ssh-agent(1): exit 0 from SIGTERM under systemd socket-activation,
preventing a graceful shutdown of an agent via systemd from
incorrectly marking the service as "failed".
* build: wrap some autoconf macros in AC_CACHE_CHECK.
This allows skipping/overriding the OSSH_CHECK_CFLAG_COMPILE and
OSSH_CHECK_CFLAG_LINK macros used to discover supported compiler
or linker flags. E.g.
$ ./configure ossh\_cv\_cflag\_\_fzero\_call\_used\_regs\_used=no
\[...\]
checking if cc supports compile flag -fzero-call-used-regs=used
and linking succeeds... (cached) no
Checksums:
SHA1 (openssh-10.1.tar.gz) = 8eef44a945a9a9a5a99213ab0d57e35b7ba60e75
SHA256 (openssh-10.1.tar.gz) = j9ymvhvdGMeAvh1oTI2YmOAwv7Ao70gbGPyPedgQsBU=
SHA1 (openssh-10.1p1.tar.gz) = 7fd17b99d1beffb47cd380d64079e920bb0bd91f
SHA256 (openssh-10.1p1.tar.gz) = ufx6K4JXlGem8vQ+SoHI4d/aYU3bT5slWq/XAgu/B1g=
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available from the mirror sites:
https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/RELEASE_KEY.asc
Reporting Bugs:
OpenSSH 10.0 was released on 2025-04-09. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
https://www.openssh.com/donations.html
Potentially-incompatible changes
* This release removes support for the weak DSA signature
algorithm, completing the deprecation process that began in
2015 (when DSA was disabled by default) and repeatedly warned
over the last 12 months.
* scp(1), sftp(1): pass "ControlMaster no" to ssh when invoked by
scp & sftp. This disables implicit session creation by these
tools when ControlMaster was set to yes/auto by configuration,
which some users found surprising. This change will not prevent
scp/sftp from using an existing multiplexing session if one had
already been created. GHPR557
* This release has the version number 10.0 and announces itself
as "SSH-2.0-OpenSSH_10.0". Software that naively matches
versions using patterns like "OpenSSH_1*" may be confused by
this.
* sshd(8): this release removes the code responsible for the
user authentication phase of the protocol from the per-
connection sshd-session binary to a new sshd-auth binary.
Splitting this code into a separate binary ensures that the
crucial pre-authentication attack surface has an entirely
disjoint address space from the code used for the rest of the
connection. It also yields a small runtime memory saving as the
authentication code will be unloaded after the authentication
phase completes. This change should be largely invisible to
users, though some log messages may now come from "sshd-auth"
instead of "sshd-session". Downstream distributors of OpenSSH
will need to package the sshd-auth binary.
* sshd(8): this release disables finite field (a.k.a modp)
Diffie-Hellman key exchange in sshd by default. Specifically,
this removes the "diffie-hellman-group*" and
"diffie-hellman-group-exchange-*" methods from the default
KEXAlgorithms list. The client is unchanged and continues to
support these methods by default. Finite field Diffie Hellman
is slow and computationally expensive for the same security
level as Elliptic Curve DH or PQ key agreement while offering
no redeeming advantages. ECDH has been specified for the SSH
protocol for 15 years and some form of ECDH has been the default
key exchange in OpenSSH for the last 14 years.
* sshd(8): this release removes the implicit fallback to compiled-
in groups for Diffie-Hellman Group Exchange KEX when the moduli
file exists but does not contain moduli within the client-
requested range. The fallback behaviour remains for the case
where the moduli file does not exist at all. This allows
administrators more explicit control over which DH groups will
be selected, but can lead to connection failures if the moduli
file is edited incorrectly. bz#2793
Changes since OpenSSH 9.9
This release contains a minor security fix as well as a number of
feature improvements and bugfixes.
Security
* sshd(8): fix the DisableForwarding directive, which was failing
to disable X11 forwarding and agent forwarding as documented.
X11 forwarding is disabled by default in the server and agent
forwarding is off by default in the client.
New features
* ssh(1): the hybrid post-quantum algorithm mlkem768x25519-sha256
is now used by default for key agreement. This algorithm is
considered to be safe against attack by quantum computers,
is guaranteed to be no less strong than the popular
curve25519-sha256 algorithm, has been standardised by NIST
and is considerably faster than the previous default.
* ssh(1): prefer AES-GCM to AES-CTR mode when selecting a cipher
for the connection. The default cipher preference list is now
Chacha20/Poly1305, AES-GCM (128/256) followed by AES-CTR
(128/192/256).
* ssh(1): add %-token and environment variable expansion to the
ssh_config SetEnv directive.
* ssh(1): allow %-token and environment variable expansion in
the ssh_config User directive, with the exception of %r and %C
which would be self-referential. bz#3477
* ssh(1), sshd(8): add "Match version" support to ssh_config and
sshd_config. Allows matching on the local version of OpenSSH,
e.g. "Match version OpenSSH_10.*".
* ssh(1): add support for "Match sessiontype" to ssh_config.
Allows matching on the type of session initially requested,
either "shell" for interactive sessions, "exec" for command
execution sessions, "subsystem" for subsystem requests, such as
sftp, or "none" for transport/forwarding-only sessions.
* ssh(1): add support for "Match command ..." support to
ssh_config, allowing matching on the remote command as specified
on the command-line.
* ssh(1): allow 'Match tagged ""' and 'Match command ""' to match
empty tag and command values respectively.
* sshd(8): allow glob(3) patterns to be used in sshd_config
AuthorizedKeysFile and AuthorizedPrincipalsFile directives.
bz2755
* sshd(1): support the VersionAddendum in the client, mirroring
the option of the same name in the server; bz2745
* ssh-agent(1): the agent will now delete all loaded keys when
signaled with SIGUSR1. This allows deletion of keys without
having access to $SSH_AUTH_SOCK.
* Portable OpenSSH, ssh-agent(1): support systemd-style socket
activation in ssh-agent using the LISTEN_PID/LISTEN_FDS
mechanism. Activated when these environment variables are set,
the agent is started with the -d or -D option and no socket path
is set. GHPR502
* ssh-keygen(1): support FIDO tokens that return no attestation
data, e.g. recent WinHello. GHPR542
* ssh-agent(1): add a "-Owebsafe-allow=..." option to allow the
default FIDO application ID allow-list to be overridden.
* Add a work-in-progress tool to verify FIDO attestation blobs
that ssh-keygen can optionally write when enrolling FIDO keys.
This tool is available under regress/misc/ssh-verify-attestation
for experimentation but is not installed by "make install".
* ssh-keygen(1): allow "-" as output file for moduli screening.
GHPR393
Bugfixes
* sshd(8): remove assumption that the sshd_config and any configs
it includes can fit in a (possibly enlarged) socket buffer.
Previously it was possible to create a sufficiently large
configuration that could cause sshd to fail to accept any
connection. sshd(8) will now actively manage sending its config
to the sshd-session sub-process.
* ssh(1): don't start the ObscureKeystrokeTiming mitigations if
there has been traffic on a X11 forwarding channel recently.
Should fix X11 forwarding performance problems when this setting
is enabled. bz3655
* ssh(1): prohibit the comma character in hostnames accepted, but
allow an underscore as the first character in a hostname.
* sftp(1): set high-water when resuming a "put". Prevents bogus
"server reordered acks" debug message.
* ssh(1), sshd(8): fix regression in openssh-9.8, which would fail
to accept "Match criteria=argument" as well as the documented
"Match criteria argument" syntax in ssh_config and sshd_config.
bz3739
* sftp(1), ssh(1): fix a number possible NULL dereference bugs,
including Coverity CIDs 405019 and 477813.
* sshd(8): fix PerSourcePenalty incorrectly using "crash" penalty
when LoginGraceTime was exceeded. bz3797
* sshd(8): fix "Match invalid-user" from incorrectly being
activated in initial configuration pass when no other predicates
were present on the match line
* sshd(8): fix debug logging of user specific delay. GHPR#552
* sshd(8): improve debug logging across sub-process boundaries.
Previously some log messages were lost early in the sshd-auth and
sshd-session processes' life.
* ssh(1): require control-escape character sequences passed via
the '-e ^x' command-line to be exactly two characters long. Avoids
one byte out-of-bounds read if ssh is invoked as "ssh -e^ ..."
GHPR368
* ssh(1), sshd(8): prevent integer overflow in x11 port handling.
These are theoretically possible if the admin misconfigured
X11DisplayOffset or the user misconfigures their own $DISPLAY,
but don't happen in normal operation. bz#3730
* ssh-keygen(1): don't mess up ssh-keygen -l output when the file
contains CR characters; GHPR236 bz3385.
* sshd(8): add rate limits to logging of connections dropped by
PerSourcePenalties. Previously these could be noisy in logs.
* ssh(1): fix argument of "Compression" directive in ssh -G config
dump, which regressed in openssh-9.8.
* sshd(8): fix a corner-case triggered by UpdateHostKeys when sshd
refuses to accept the signature returned by an agent holding host
keys during the hostkey rotation sub-protocol. This situation
could occur in situations where a PKCS#11 smartcard that lacked
support for particular signature algorithms was used to store
host keys.
* ssh-keygen(1): when using RSA keys to sign messages with
"ssh-keygen -Y", select the signature algorithm based on the
requested hash algorithm ("-Ohashalg=xxx"). This allows using
something other than the default of rsa-sha2-512, which may not
be supported on all signing backends, e.g. some smartcards only
support SHA256.
* ssh(1), sshd(8), ssh-keyscan(1): fix ML-KEM768x25519 KEX on
big-endian systems.
* Many regression and interop test improvements.
Portability
* All: add support for AWS-LC (AWS libcrypto). bz3784
* sshd(8): add wtmpdb support as a Y2038 safe wtmp replacement.
* sshd(8): add support for locking sshd into memory, enabled with
the --with-linux-memlock-onfault configure flag.
* Add support for building a standalone sk-libfido2 library,
enabled by --with-security-key-standalone
* ssh(1), sshd(8), ssh-keyscan(1): include __builtin_popcount
replacement function. for compilers that lack it.
* All: Check for and replace le32toh, le64toh, htole64 separately.
It appears that at least some versions of endian.h in glibc do
not have the latter two. bz#3794
* Remove ancient RHL 6.x config in RPM spec.
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available from the mirror sites:
https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/RELEASE_KEY.asc
Reporting Bugs:
OpenSSH 9.9p2 was released on 2025-02-18. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
https://www.openssh.com/donations.html
Changes since OpenSSH 9.9p1
This release fixes two security bugs.
Security
* Fix CVE-2025-26465 - ssh(1) in OpenSSH versions 6.8p1 to 9.9p1
(inclusive) contained a logic error that allowed an on-path
attacker (a.k.a MITM) to impersonate any server when the
VerifyHostKeyDNS option is enabled. This option is off by default.
* Fix CVE-2025-26466 - sshd(8) in OpenSSH versions 9.5p1 to 9.9p1
(inclusive) is vulnerable to a memory/CPU denial-of-service related
to the handling of SSH2_MSG_PING packets. This condition may be
mitigated using the existing PerSourcePenalties feature.
Both vulnerabilities were discovered and demonstrated to be exploitable
by the Qualys Security Advisory team. We thank them for their detailed
review of OpenSSH.
For OpenBSD, fixes to these problems are available as errata; refer
to https://www.openbsd.org/errata.html
Bugfixes
* ssh(1), sshd(8): fix regression in Match directive that caused
failures when predicates and their arguments were separated by '='
characters instead of whitespace (bz3739).
* sshd(8): fix the "Match invalid-user" predicate, which was matching
incorrectly in the initial pass of config evaluation.
* ssh(1), sshd(8), ssh-keyscan(1): fix mlkem768x25519-sha256 key
exchange on big-endian systems.
* Fix a number of build problems on particular operating systems /
configurations.
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available from the mirror sites:
https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/RELEASE_KEY.asc
Reporting Bugs:
OpenSSH 9.9 was released on 2024-09-19. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
https://www.openssh.com/donations.html
Future deprecation notice
OpenSSH plans to remove support for the DSA signature algorithm in
early 2025. This release disables DSA by default at compile time.
DSA, as specified in the SSHv2 protocol, is inherently weak - being
limited to a 160 bit private key and use of the SHA1 digest. Its
estimated security level is only 80 bits symmetric equivalent.
OpenSSH has disabled DSA keys by default since 2015 but has retained
run-time optional support for them. DSA was the only mandatory-to-
implement algorithm in the SSHv2 RFCs, mostly because alternative
algorithms were encumbered by patents when the SSHv2 protocol was
specified.
This has not been the case for decades at this point and better
algorithms are well supported by all actively-maintained SSH
implementations. We do not consider the costs of maintaining DSA
in OpenSSH to be justified and hope that removing it from OpenSSH
can accelerate its wider deprecation in supporting cryptography
libraries.
Currently DSA is disabled at compile time. The final step of
removing DSA support entirely is planned for the first OpenSSH
release of 2025.
DSA support may be re-enabled on OpenBSD by setting "DSAKEY=yes"
in Makefile.inc. To enable DSA support in portable OpenSSH, pass
the "--enable-dsa-keys" option to configure.
Potentially-incompatible changes
* ssh(1): remove support for pre-authentication compression.
OpenSSH has only supported post-authentication compression in
the server for some years. Compression before authentication
significantly increases the attack surface of SSH servers and risks
creating oracles that reveal information about information sent
during authentication.
* ssh(1), sshd(8): processing of the arguments to the "Match"
configuration directive now follows more shell-like rules for
quoted strings, including allowing nested quotes and \-escaped
characters. If configurations contained workarounds for the
previous simplistic quote handling then they may need to be
adjusted. If this is the case, it's most likely to be in the
arguments to a "Match exec" confition. In this case, moving the
command to be evaluated from the Match line to an external shell
script is easiest way to preserve compatibility with both the old
and new versions.
Changes since OpenSSH 9.8
This release contains a number of new features and bugfixes.
New features
* ssh(1), sshd(8): add support for a new hybrid post-quantum key
exchange based on the FIPS 203 Module-Lattice Key Enapsulation
mechanism (ML-KEM) combined with X25519 ECDH as described by
https://datatracker.ietf.org/doc/html/draft-kampanakis-curdle-ssh-pq-ke-03
This algorithm "mlkem768x25519-sha256" is available by default.
* ssh(1): the ssh_config "Include" directive can now expand
environment as well as the same set of %-tokens "Match Exec"
supports.
* sshd(8): add a sshd_config "RefuseConnection" option that, if set
will terminate the connection at the first authentication request.
* sshd(8): add a "refuseconnection" penalty class to sshd_config
PerSourcePenalties that is applied when a connection is dropped by
the new RefuseConnection keyword.
* sshd(8): add a "Match invalid-user" predicate to sshd_config Match
options that matches when the target username is not valid on the
server.
* ssh(1), sshd(8): update the Streamlined NTRUPrime code to a
substantially faster implementation.
* ssh(1), sshd(8): the hybrid Streamlined NTRUPrime/X25519 key
exchange algorithm now has an IANA-assigned name in addition to
the "@openssh.com" vendor extension name. This algorithm is now
also available under this name "sntrup761x25519-sha512"
* ssh(1), sshd(8), ssh-agent(1): prevent private keys from being
included in core dump files for most of their lifespans. This is
in addition to pre-existing controls in ssh-agent(1) and sshd(8)
that prevented coredumps. This feature is supported on OpenBSD,
Linux and FreeBSD.
* All: convert key handling to use the libcrypto EVP_PKEY API, with
the exception of DSA.
* sshd(8): add a random amount of jitter (up to 4 seconds) to the
grace login time to make its expiry unpredictable.
Bugfixes
* sshd(8): relax absolute path requirement back to what it was prior
to OpenSSH 9.8, which incorrectly required that sshd was started
with an absolute path in inetd mode. bz3717
* sshd(8): fix regression introduced in openssh-9.8 that swapped the
order of source and destination addresses in some sshd log messages.
* sshd(8): do not apply authorized_keys options when signature
verification fails. Prevents more restrictive key options being
incorrectly applied to subsequent keys in authorized_keys. bz3733
* ssh-keygen(1): include pathname in some of ssh-keygen's passphrase
prompts. Helps the user know what's going on when ssh-keygen is
invoked via other tools. Requested in GHPR503
* ssh(1), ssh-add(1): make parsing user@host consistently look for
the last '@' in the string rather than the first. This makes it
possible to more consistently use usernames that contain '@'
characters.
* ssh(1), sshd(8): be more strict in parsing key type names. Only
allow short names (e.g "rsa") in user-interface code and require
full SSH protocol names (e.g. "ssh-rsa") everywhere else. bz3725
* regress: many performance and correctness improvements to the
re-keying regression test.
* ssh-keygen(1): clarify that ed25519 is the default key type
generated and clarify that rsa-sha2-512 is the default signature
scheme when RSA is in use. GHPR505
* sshd(8): fix minor memory leak in Subsystem option parsing; GHPR515
* All: additional hardening and consistency checks for the sshbuf
code.
* sshd(8): reduce default logingrace penalty to ensure that a single
forgotten login that times out will be below the penalty threshold.
* ssh(1): fix proxy multiplexing (-O proxy) bug. If a mux started with
ControlPersist then later has a forwarding added using mux proxy
connection and the forwarding was used, then when the mux proxy
session terminated, the mux master process would issue a bad message
that terminated the connection.
Portability
* sync contrib/ssh-copy-id to the latest upstream version.
* regress: improve portablility for some awk(1) usage (e.g. Solaris)
* In the contrib/redhat RPM spec file, without_openssl was previously
incorrectly enabled unconditionally.
* sshd(8) restore audit call before exit that regressed in openssh-9.8
Fixes an issue where the SSH_CONNECTION_ABANDON event was not
recorded.
* sshd(8): add support for class-imposed login restrictions on FreeBSD.
Allowing auth_hostok(3) and auth_timeok(3) to control logins.
* Build fixes for Musl libc.
* Fix detection of setres*id on GNU/Hurd
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available from the mirror sites:
https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/RELEASE_KEY.asc
Reporting Bugs:
OpenSSH 9.8 was released on 2024-07-01. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
https://www.openssh.com/donations.html
Security
This release contains fixes for two security problems, one critical
and one minor.
- Race condition in sshd(8)
A critical vulnerability in sshd(8) was present in Portable OpenSSH
versions between 8.5p1 and 9.7p1 (inclusive) that may allow arbitrary
code execution with root privileges.
Successful exploitation has been demonstrated on 32-bit Linux/glibc
systems with ASLR. Under lab conditions, the attack requires on
average 6-8 hours of continuous connections up to the maximum the
server will accept. Exploitation on 64-bit systems is believed to be
possible but has not been demonstrated at this time. It's likely that
these attacks will be improved upon.
Exploitation on non-glibc systems is conceivable but has not been
examined. Systems that lack ASLR or users of downstream Linux
distributions that have modified OpenSSH to disable per-connection
ASLR re-randomisation (yes - this is a thing, no - we don't
understand why) may potentially have an easier path to exploitation.
OpenBSD is not vulnerable.
We thank the Qualys Security Advisory Team for discovering, reporting
and demonstrating exploitability of this problem, and for providing
detailed feedback on additional mitigation measures.
- Logic error in ssh(1) ObscureKeystrokeTiming
In OpenSSH version 9.5 through 9.7 (inclusive), when connected to an
OpenSSH server version 9.5 or later, a logic error in the ssh(1)
ObscureKeystrokeTiming feature (on by default) rendered this feature
ineffective - a passive observer could still detect which network
packets contained real keystrokes when the countermeasure was active
because both fake and real keystroke packets were being sent
unconditionally.
This bug was found by Philippos Giavridis and also independently by
Jacky Wei En Kung, Daniel Hugenroth and Alastair Beresford of the
University of Cambridge Computer Lab.
Worse, the unconditional sending of both fake and real keystroke
packets broke another long-standing timing attack mitigation. Since
OpenSSH 2.9.9 sshd(8) has sent fake keystroke echo packets for
traffic received on TTYs in echo-off mode, such as when entering a
password into su(8) or sudo(8). This bug rendered these fake
keystroke echoes ineffective and could allow a passive observer of
a SSH session to once again detect when echo was off and obtain
fairly limited timing information about keystrokes in this situation
(20ms granularity by default).
This additional implication of the bug was identified by Jacky Wei
En Kung, Daniel Hugenroth and Alastair Beresford and we thank them
for their detailed analysis.
This bug does not affect connections when ObscureKeystrokeTiming
was disabled or sessions where no TTY was requested.
Future deprecation notice
OpenSSH plans to remove support for the DSA signature algorithm in
early 2025. This release disables DSA by default at compile time.
DSA, as specified in the SSHv2 protocol, is inherently weak - being
limited to a 160 bit private key and use of the SHA1 digest. Its
estimated security level is only 80 bits symmetric equivalent.
OpenSSH has disabled DSA keys by default since 2015 but has retained
run-time optional support for them. DSA was the only mandatory-to-
implement algorithm in the SSHv2 RFCs, mostly because alternative
algorithms were encumbered by patents when the SSHv2 protocol was
specified.
This has not been the case for decades at this point and better
algorithms are well supported by all actively-maintained SSH
implementations. We do not consider the costs of maintaining DSA
in OpenSSH to be justified and hope that removing it from OpenSSH
can accelerate its wider deprecation in supporting cryptography
libraries.
This release, and its deactivation of DSA by default at compile-time,
marks the second step in our timeline to finally deprecate DSA. The
final step of removing DSA support entirely is planned for the first
OpenSSH release of 2025.
DSA support may be re-enabled in OpenBSD by setting "DSAKEY=yes"
in Makefile.inc. To enable DSA support in portable OpenSSH, pass
the "--enable-dsa-keys" option to configure.
Potentially-incompatible changes
* all: as mentioned above, the DSA signature algorithm is now
disabled at compile time.
* sshd(8): the server will now block client addresses that
repeatedly fail authentication, repeatedly connect without ever
completing authentication or that crash the server. See the
discussion of PerSourcePenalties below for more information.
Operators of servers that accept connections from many users, or
servers that accept connections from addresses behind NAT or
proxies may need to consider these settings.
* sshd(8): the server has been split into a listener binary, sshd(8),
and a per-session binary "sshd-session". This allows for a much
smaller listener binary, as it no longer needs to support the SSH
protocol. As part of this work, support for disabling privilege
separation (which previously required code changes to disable) and
disabling re-execution of sshd(8) has been removed. Further
separation of sshd-session into additional, minimal binaries is
planned for the future.
* sshd(8): several log messages have changed. In particular, some
log messages will be tagged with as originating from a process
named "sshd-session" rather than "sshd".
* ssh-keyscan(1): this tool previously emitted comment lines
containing the hostname and SSH protocol banner to standard error.
This release now emits them to standard output, but adds a new
"-q" flag to silence them altogether.
* sshd(8): (portable OpenSSH only) sshd will no longer use argv[0]
as the PAM service name. A new "PAMServiceName" sshd_config(5)
directive allows selecting the service name at runtime. This
defaults to "sshd". bz2101
* (portable OpenSSH only) Automatically-generated files, such as
configure, config.h.in, etc will now be checked in to the portable
OpenSSH git release branch (e.g. V_9_8). This should ensure that
the contents of the signed release branch exactly match the
contents of the signed release tarball.
Changes since OpenSSH 9.7
This release contains mostly bugfixes.
New features
* sshd(8): as described above, sshd(8) will now penalise client
addresses that, for various reasons, do not successfully complete
authentication. This feature is controlled by a new sshd_config(5)
PerSourcePenalties option and is on by default.
sshd(8) will now identify situations where the session did not
authenticate as expected. These conditions include when the client
repeatedly attempted authentication unsuccessfully (possibly
indicating an attack against one or more accounts, e.g. password
guessing), or when client behaviour caused sshd to crash (possibly
indicating attempts to exploit bugs in sshd).
When such a condition is observed, sshd will record a penalty of
some duration (e.g. 30 seconds) against the client's address. If
this time is above a minimum configurable threshold, then all
connections from the client address will be refused (along with any
others in the same PerSourceNetBlockSize CIDR range) until the
penalty expire.
Repeated offenses by the same client address will accrue greater
penalties, up to a configurable maximum. Address ranges may be
fully exempted from penalties, e.g. to guarantee access from a set
of trusted management addresses, using the new sshd_config(5)
PerSourcePenaltyExemptList option.
We hope these options will make it significantly more difficult for
attackers to find accounts with weak/guessable passwords or exploit
bugs in sshd(8) itself. This option is enabled by default.
* ssh(8): allow the HostkeyAlgorithms directive to disable the
implicit fallback from certificate host key to plain host keys.
Bugfixes
* misc: fix a number of inaccuracies in the PROTOCOL.*
documentation files. GHPR430 GHPR487
* all: switch to strtonum(3) for more robust integer parsing in most
places.
* ssh(1), sshd(8): correctly restore sigprocmask around ppoll()
* ssh-keysign(8): stricter validation of messaging socket fd GHPR492
* sftp(1): flush stdout after writing "sftp>" prompt when not using
editline. GHPR480
* sftp-server(8): fix home-directory extension implementation, it
previously always returned the current user's home directory
contrary to the spec. GHPR477
* ssh-keyscan(1): do not close stdin to prevent error messages when
stdin is read multiple times. E.g.
echo localhost | ssh-keyscan -f - -f -
* regression tests: fix rekey test that was testing the same KEX
algorithm repeatedly instead of testing all of them. bz3692
* ssh_config(5), sshd_config(5): clarify the KEXAlgorithms directive
documentation, especially around what is supported vs available.
bz3701.
Portability
* sshd(8): expose SSH_AUTH_INFO_0 always to PAM auth modules
unconditionally. The previous behaviour was to expose it only when
particular authentication methods were in use.
* build: fix OpenSSL ED25519 support detection. An incorrect function
signature in configure.ac previously prevented enabling the recently
added support for ED25519 private keys in PEM PKCS8 format.
* ssh(1), ssh-agent(8): allow the presence of the WAYLAND_DISPLAY
environment variable to enable SSH_ASKPASS, similarly to the X11
DISPLAY environment variable. GHPR479
* build: improve detection of the -fzero-call-used-regs compiler
flag. bz3673.
* build: relax OpenSSL version check to accept all OpenSSL 3.x
versions.
* sshd(8): add support for notifying systemd on server listen and
reload, using a standalone implementation that doesn't depend on
libsystemd. bz2641
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available from the mirror sites:
https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/RELEASE_KEY.asc
Reporting Bugs:
OpenSSH 9.7 was released on 2024-03-11. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
https://www.openssh.com/donations.html
Future deprecation notice
OpenSSH plans to remove support for the DSA signature algorithm in
early 2025 and compile-time disable it later this year.
DSA, as specified in the SSHv2 protocol, is inherently weak - being
limited to a 160 bit private key and use of the SHA1 digest. Its
estimated security level is only 80 bits symmetric equivalent.
OpenSSH has disabled DSA keys by default since 2015 but has retained
run-time optional support for them. DSA was the only mandatory-to-
implement algorithm in the SSHv2 RFCs[3], mostly because alternative
algorithms were encumbered by patents when the SSHv2 protocol was
specified.
This has not been the case for decades at this point and better
algorithms are well supported by all actively-maintained SSH
implementations. We do not consider the costs of maintaining DSA in
OpenSSH to be justified and hope that removing it from OpenSSH can
accelerate its wider deprecation in supporting cryptography
libraries.
This release makes DSA support in OpenSSH compile-time optional,
defaulting to on. We intend the next release to change the default
to disable DSA at compile time. The first OpenSSH release of 2025
will remove DSA support entirely.
Changes since OpenSSH 9.6
This release contains mostly bugfixes.
New features
* ssh(1), sshd(8): add a "global" ChannelTimeout type that watches
all open channels and will close all open channels if there is no
traffic on any of them for the specified interval. This is in
addition to the existing per-channel timeouts added recently.
This supports situations like having both session and x11
forwarding channels open where one may be idle for an extended
period but the other is actively used. The global timeout could
close both channels when both have been idle for too long.
* All: make DSA key support compile-time optional, defaulting to on.
Bugfixes
* sshd(8): don't append an unnecessary space to the end of subsystem
arguments (bz3667)
* ssh(1): fix the multiplexing "channel proxy" mode, broken when
keystroke timing obfuscation was added. (GHPR#463)
* ssh(1), sshd(8): fix spurious configuration parsing errors when
options that accept array arguments are overridden (bz3657).
* ssh-agent(1): fix potential spin in signal handler (bz3670)
* Many fixes to manual pages and other documentation, including
GHPR#462, GHPR#454, GHPR#442 and GHPR#441.
* Greatly improve interop testing against PuTTY.
Portability
* Improve the error message when the autoconf OpenSSL header check
fails (bz#3668)
* Improve detection of broken toolchain -fzero-call-used-regs support
(bz3645).
* Fix regress/misc/fuzz-harness fuzzers and make them compile without
warnings when using clang16
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available from the mirror sites:
https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/RELEASE_KEY.asc
Reporting Bugs:
OpenSSH 9.6 was released on 2023-12-18. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
https://www.openssh.com/donations.html
Changes since OpenSSH 9.5
This release contains a number of security fixes, some small features
and bugfixes.
Security
This release contains fixes for a newly-discovered weakness in the
SSH transport protocol, a logic error relating to constrained PKCS#11
keys in ssh-agent(1) and countermeasures for programs that invoke
ssh(1) with user or hostnames containing invalid characters.
* ssh(1), sshd(8): implement protocol extensions to thwart the
so-called "Terrapin attack" discovered by Fabian Bäumer, Marcus
Brinkmann and Jörg Schwenk. This attack allows a MITM to effect a
limited break of the integrity of the early encrypted SSH transport
protocol by sending extra messages prior to the commencement of
encryption, and deleting an equal number of consecutive messages
immediately after encryption starts. A peer SSH client/server
would not be able to detect that messages were deleted.
While cryptographically novel, the security impact of this attack
is fortunately very limited as it only allows deletion of
consecutive messages, and deleting most messages at this stage of
the protocol prevents user authentication from proceeding and
results in a stuck connection.
The most serious identified impact is that it lets a MITM to
delete the SSH2_MSG_EXT_INFO message sent before authentication
starts, allowing the attacker to disable a subset of the keystroke
timing obfuscation features introduced in OpenSSH 9.5. There is no
other discernible impact to session secrecy or session integrity.
OpenSSH 9.6 addresses this protocol weakness through a new "strict
KEX" protocol extension that will be automatically enabled when
both the client and server support it. This extension makes
two changes to the SSH transport protocol to improve the integrity
of the initial key exchange.
Firstly, it requires endpoints to terminate the connection if any
unnecessary or unexpected message is received during key exchange
(including messages that were previously legal but not strictly
required like SSH2_MSG_DEBUG). This removes most malleability from
the early protocol.
Secondly, it resets the Message Authentication Code counter at the
conclusion of each key exchange, preventing previously inserted
messages from being able to make persistent changes to the
sequence number across completion of a key exchange. Either of
these changes should be sufficient to thwart the Terrapin Attack.
More details of these changes are in the PROTOCOL file in the
OpenSSH source distribition.
* ssh-agent(1): when adding PKCS#11-hosted private keys while
specifying destination constraints, if the PKCS#11 token returned
multiple keys then only the first key had the constraints applied.
Use of regular private keys, FIDO tokens and unconstrained keys
are unaffected.
* ssh(1): if an invalid user or hostname that contained shell
metacharacters was passed to ssh(1), and a ProxyCommand,
LocalCommand directive or "match exec" predicate referenced the
user or hostname via %u, %h or similar expansion token, then
an attacker who could supply arbitrary user/hostnames to ssh(1)
could potentially perform command injection depending on what
quoting was present in the user-supplied ssh_config(5) directive.
This situation could arise in the case of git submodules, where
a repository could contain a submodule with shell characters in
its user/hostname. Git does not ban shell metacharacters in user
or host names when checking out repositories from untrusted
sources.
Although we believe it is the user's responsibility to ensure
validity of arguments passed to ssh(1), especially across a
security boundary such as the git example above, OpenSSH 9.6 now
bans most shell metacharacters from user and hostnames supplied
via the command-line. This countermeasure is not guaranteed to be
effective in all situations, as it is infeasible for ssh(1) to
universally filter shell metacharacters potentially relevant to
user-supplied commands.
User/hostnames provided via ssh_config(5) are not subject to these
restrictions, allowing configurations that use strange names to
continue to be used, under the assumption that the user knows what
they are doing in their own configuration files.
Potentially incompatible changes
* ssh(1), sshd(8): the RFC4254 connection/channels protocol provides
a TCP-like window mechanism that limits the amount of data that
can be sent without acceptance from the peer. In cases where this
limit was exceeded by a non-conforming peer SSH implementation,
ssh(1)/sshd(8) previously discarded the extra data. From OpenSSH
9.6, ssh(1)/sshd(8) will now terminate the connection if a peer
exceeds the window limit by more than a small grace factor. This
change should have no effect of SSH implementations that follow
the specification.
New features
* ssh(1): add a %j token that expands to the configured ProxyJump
hostname (or the empty string if this option is not being used)
that can be used in a number of ssh_config(5) keywords. bz3610
* ssh(1): add ChannelTimeout support to the client, mirroring the
same option in the server and allowing ssh(1) to terminate
quiescent channels.
* ssh(1), sshd(8), ssh-add(1), ssh-keygen(1): add support for
reading ED25519 private keys in PEM PKCS8 format. Previously
only the OpenSSH private key format was supported.
* ssh(1), sshd(8): introduce a protocol extension to allow
renegotiation of acceptable signature algorithms for public key
authentication after the server has learned the username being
used for authentication. This allows varying sshd_config(5)
PubkeyAcceptedAlgorithms in a "Match user" block.
* ssh-add(1), ssh-agent(1): add an agent protocol extension to allow
specifying certificates when loading PKCS#11 keys. This allows the
use of certificates backed by PKCS#11 private keys in all OpenSSH
tools that support ssh-agent(1). Previously only ssh(1) supported
this use-case.
Bugfixes
* ssh(1): when deciding whether to enable the keystroke timing
obfuscation, enable it only if a channel with a TTY is active.
* ssh(1): switch mainloop from poll(3) to ppoll(3) and mask signals
before checking flags set in signal handler. Avoids potential
race condition between signaling ssh to exit and polling. bz3531
* ssh(1): when connecting to a destination with both the
AddressFamily and CanonicalizeHostname directives in use,
the AddressFamily directive could be ignored. bz5326
* sftp(1): correct handling of the limits@openssh.com option when
the server returned an unexpected message.
* A number of fixes to the PuTTY and Dropbear regress/integration
tests.
* ssh(1): release GSS OIDs only at end of authentication, avoiding
unnecessary init/cleanup cycles. bz2982
* ssh_config(5): mention "none" is a valid argument to IdentityFile
in the manual. bz3080
* scp(1): improved debugging for paths from the server rejected for
not matching the client's glob(3) pattern in old SCP/RCP protocol
mode.
* ssh-agent(1): refuse signing operations on destination-constrained
keys if a previous session-bind operation has failed. This may
prevent a fail-open situation in future if a user uses a mismatched
ssh(1) client and ssh-agent(1) where the client supports a key type
that the agent does not support.
Portability
* Better identify unsupported and unstable compiler flags, such as
-fzero-call-used-regs which has been unstable across a several
clang releases.
* A number of fixes to regression test reliability and log
collection.
* Update the OpenSSL dependency in the RPM specification.
* sshd(8): for OpenSolaris systems that support privilege limitation
via the getpflags() interface, prefer using the newer PRIV_XPOLICY
to PRIV_LIMIT. bz2833
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available from the mirror sites:
https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/RELEASE_KEY.asc
Reporting Bugs:
OpenSSH 9.5 was released on 2023-10-04. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
https://www.openssh.com/donations.html
Changes since OpenSSH 9.4
This release fixes a number of bugs and adds some small features.
Potentially incompatible changes
* ssh-keygen(1): generate Ed25519 keys by default. Ed25519 public keys
are very convenient due to their small size. Ed25519 keys are
specified in RFC 8709 and OpenSSH has supported them since version 6.5
(January 2014).
* sshd(8): the Subsystem directive now accurately preserves quoting of
subsystem commands and arguments. This may change behaviour for exotic
configurations, but the most common subsystem configuration
(sftp-server) is unlikely to be affected.
New features
* ssh(1): add keystroke timing obfuscation to the client. This attempts
to hide inter-keystroke timings by sending interactive traffic at
fixed intervals (default: every 20ms) when there is only a small
amount of data being sent. It also sends fake "chaff" keystrokes for
a random interval after the last real keystroke. These are
controlled by a new ssh_config ObscureKeystrokeTiming keyword.
* ssh(1), sshd(8): Introduce a transport-level ping facility. This adds
a pair of SSH transport protocol messages SSH2_MSG_PING/PONG to
implement a ping capability. These messages use numbers in the "local
extensions" number space and are advertised using a "ping@openssh.com"
ext-info message with a string version number of "0".
* sshd(8): allow override of Subsystem directives in sshd Match blocks.
Bugfixes
* scp(1): fix scp in SFTP mode recursive upload and download of
directories that contain symlinks to other directories. In scp mode,
the links would be followed, but in SFTP mode they were not. bz3611
* ssh-keygen(1): handle cr+lf (instead of just cr) line endings in
sshsig signature files.
* ssh(1): interactive mode for ControlPersist sessions if they
originally requested a tty.
* sshd(8): make PerSourceMaxStartups first-match-wins
* sshd(8): limit artificial login delay to a reasonable maximum (5s)
and don't delay at all for the "none" authentication mechanism.cw
bz3602
* sshd(8): Log errors in kex_exchange_identification() with level
verbose instead of error to reduce preauth log spam. All of those
get logged with a more generic error message by sshpkt_fatal().
* sshd(8): correct math for ClientAliveInterval that caused the probes
to be sent less frequently than configured.
* ssh(1): fix regression in OpenSSH 9.4 (mux.c r1.99) that caused
multiplexed sessions to ignore SIGINT under some circumstances.
Portability
* Avoid clang zero-call-used-regs=all bug on Apple compilers, which
for some reason have version numbers that do not match the upstream
clang version numbers. bz#3584
* Fix configure test for zlib 1.3 and later/development versions. bz3604
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available from the mirror sites:
https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/RELEASE_KEY.asc
Reporting Bugs:
OpenSSH 9.4 was released on 2023-08-10. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
https://www.openssh.com/donations.html
Changes since OpenSSH 9.3p2
This release fixes a number of bugs and adds some small features.
Potentially incompatible changes
* This release removes support for older versions of libcrypto.
OpenSSH now requires LibreSSL >= 3.1.0 or OpenSSL >= 1.1.1.
Note that these versions are already deprecated by their upstream
vendors.
* ssh-agent(1): PKCS#11 modules must now be specified by their full
paths. Previously dlopen(3) could search for them in system
library directories.
New features
* ssh(1): allow forwarding Unix Domain sockets via ssh -W.
* ssh(1): add support for configuration tags to ssh(1).
This adds a ssh_config(5) "Tag" directive and corresponding
"Match tag" predicate that may be used to select blocks of
configuration similar to the pf.conf(5) keywords of the same
name.
* ssh(1): add a "match localnetwork" predicate. This allows matching
on the addresses of available network interfaces and may be used to
vary the effective client configuration based on network location.
* ssh(1), sshd(8), ssh-keygen(1): infrastructure support for KRL
extensions. This defines wire formats for optional KRL extensions
and implements parsing of the new submessages. No actual extensions
are supported at this point.
* sshd(8): AuthorizedPrincipalsCommand and AuthorizedKeysCommand now
accept two additional %-expansion sequences: %D which expands to
the routing domain of the connected session and %C which expands
to the addresses and port numbers for the source and destination
of the connection.
* ssh-keygen(1): increase the default work factor (rounds) for the
bcrypt KDF used to derive symmetric encryption keys for passphrase
protected key files by 50%.
Bugfixes
* ssh-agent(1): improve isolation between loaded PKCS#11 modules
by running separate ssh-pkcs11-helpers for each loaded provider.
* ssh(1): make -f (fork after authentication) work correctly with
multiplexed connections, including ControlPersist. bz3589 bz3589
* ssh(1): make ConnectTimeout apply to multiplexing sockets and not
just to network connections.
* ssh-agent(1), ssh(1): improve defences against invalid PKCS#11
modules being loaded by checking that the requested module
contains the required symbol before loading it.
* sshd(8): fix AuthorizedPrincipalsCommand when AuthorizedKeysCommand
appears before it in sshd_config. Since OpenSSH 8.7 the
AuthorizedPrincipalsCommand directive was incorrectly ignored in
this situation. bz3574
* sshd(8), ssh(1), ssh-keygen(1): remove vestigal support for KRL
signatures When the KRL format was originally defined, it included
support for signing of KRL objects. However, the code to sign KRLs
and verify KRL signatures was never completed in OpenSSH. This
release removes the partially-implemented code to verify KRLs.
All OpenSSH tools now ignore KRL_SECTION_SIGNATURE sections in
KRL files.
* All: fix a number of memory leaks and unreachable/harmless integer
overflows.
* ssh-agent(1), ssh(1): don't truncate strings logged from PKCS#11
modules; GHPR406
* sshd(8), ssh(1): better validate CASignatureAlgorithms in
ssh_config and sshd_config. Previously this directive would accept
certificate algorithm names, but these were unusable in practice as
OpenSSH does not support CA chains. bz3577
* ssh(1): make `ssh -Q CASignatureAlgorithms` only list signature
algorithms that are valid for CA signing. Previous behaviour was
to list all signing algorithms, including certificate algorithms.
* ssh-keyscan(1): gracefully handle systems where rlimits or the
maximum number of open files is larger than INT_MAX; bz3581
* ssh-keygen(1): fix "no comment" not showing on when running
`ssh-keygen -l` on multiple keys where one has a comment and other
following keys do not. bz3580
* scp(1), sftp(1): adjust ftruncate() logic to handle servers that
reorder requests. Previously, if the server reordered requests then
the resultant file would be erroneously truncated.
* ssh(1): don't incorrectly disable hostname canonicalization when
CanonicalizeHostname=yes and ProxyJump was explicitly set to
"none". bz3567
* scp(1): when copying local->remote, check that the source file
exists before opening an SFTP connection to the server. Based on
GHPR#370
Portability
* All: a number of build fixes for various platforms and
configuration combinations.
* sshd(8): provide a replacement for the SELinux matchpathcon()
function, which is deprecated.
* All: relax libcrypto version checks for OpenSSL >=3. Beyond
OpenSSL 3.0, the ABI compatibility guarantees are wider (only
the library major must match instead of major and minor in
earlier versions). bz#3548.
* Tests: fix build problems for the sk-dummy.so FIDO provider module
used in some tests.
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available from the mirror sites:
https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/RELEASE_KEY.asc
Reporting Bugs:
OpenSSH 9.3p2 was released on 2023-07-19. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
https://www.openssh.com/donations.html
Changes since OpenSSH 9.3
This release fixes a security bug.
Security
Fix CVE-2023-38408 - a condition where specific libraries loaded via
ssh-agent(1)'s PKCS#11 support could be abused to achieve remote
code execution via a forwarded agent socket if the following
conditions are met:
* Exploitation requires the presence of specific libraries on
the victim system.
* Remote exploitation requires that the agent was forwarded
to an attacker-controlled system.
Exploitation can also be prevented by starting ssh-agent(1) with an
empty PKCS#11/FIDO allowlist (ssh-agent -P '') or by configuring
an allowlist that contains only specific provider libraries.
This vulnerability was discovered and demonstrated to be exploitable
by the Qualys Security Advisory team.
In addition to removing the main precondition for exploitation,
this release removes the ability for remote ssh-agent(1) clients
to load PKCS#11 modules by default (see below).
Potentially-incompatible changes
* ssh-agent(8): the agent will now refuse requests to load PKCS#11
modules issued by remote clients by default. A flag has been added
to restore the previous behaviour "-Oallow-remote-pkcs11".
Note that ssh-agent(8) depends on the SSH client to identify
requests that are remote. The OpenSSH >=8.9 ssh(1) client does
this, but forwarding access to an agent socket using other tools
may circumvent this restriction.
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available from the mirror sites:
https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/RELEASE_KEY.asc
Reporting Bugs:
OpenSSH 9.3 was released on 2023-03-15. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
https://www.openssh.com/donations.html
Changes since OpenSSH 9.2
This release fixes a number of security bugs.
Security
This release contains fixes for a security problem and a memory
safety problem. The memory safety problem is not believed to be
exploitable, but we report most network-reachable memory faults as
security bugs.
* ssh-add(1): when adding smartcard keys to ssh-agent(1) with the
per-hop destination constraints (ssh-add -h ...) added in OpenSSH
8.9, a logic error prevented the constraints from being
communicated to the agent. This resulted in the keys being added
without constraints. The common cases of non-smartcard keys and
keys without destination constraints are unaffected. This problem
was reported by Luci Stanescu.
* ssh(1): Portable OpenSSH provides an implementation of the
getrrsetbyname(3) function if the standard library does not
provide it, for use by the VerifyHostKeyDNS feature. A
specifically crafted DNS response could cause this function to
perform an out-of-bounds read of adjacent stack data, but this
condition does not appear to be exploitable beyond denial-of-
service to the ssh(1) client.
The getrrsetbyname(3) replacement is only included if the system's
standard library lacks this function and portable OpenSSH was not
compiled with the ldns library (--with-ldns). getrrsetbyname(3) is
only invoked if using VerifyHostKeyDNS to fetch SSHFP records. This
problem was found by the Coverity static analyzer.
New features
* ssh-keygen(1), ssh-keyscan(1): accept -Ohashalg=sha1|sha256 when
outputting SSHFP fingerprints to allow algorithm selection. bz3493
* sshd(8): add a `sshd -G` option that parses and prints the
effective configuration without attempting to load private keys
and perform other checks. This allows usage of the option before
keys have been generated and for configuration evaluation and
verification by unprivileged users.
Bugfixes
* scp(1), sftp(1): fix progressmeter corruption on wide displays;
bz3534
* ssh-add(1), ssh-keygen(1): use RSA/SHA256 when testing usability
of private keys as some systems are starting to disable RSA/SHA1
in libcrypto.
* sftp-server(8): fix a memory leak. GHPR363
* ssh(1), sshd(8), ssh-keyscan(1): remove vestigal protocol
compatibility code and simplify what's left.
* Fix a number of low-impact Coverity static analysis findings.
These include several reported via bz2687
* ssh_config(5), sshd_config(5): mention that some options are not
first-match-wins.
* Rework logging for the regression tests. Regression tests will now
capture separate logs for each ssh and sshd invocation in a test.
* ssh(1): make `ssh -Q CASignatureAlgorithms` work as the manpage
says it should; bz3532.
* ssh(1): ensure that there is a terminating newline when adding a
new entry to known_hosts; bz3529
Portability
* sshd(8): harden Linux seccomp sandbox. Move to an allowlist of
mmap(2), madvise(2) and futex(2) flags, removing some concerning
kernel attack surface.
* sshd(8): improve Linux seccomp-bpf sandbox for older systems;
bz3537
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available from the mirror sites:
https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/RELEASE_KEY.asc
Reporting Bugs:
OpenSSH 9.2 was released on 2023-02-02. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
https://www.openssh.com/donations.html
Changes since OpenSSH 9.1
This release fixes a number of security bugs.
Security
This release contains fixes for two security problems and a memory
safety problem. The memory safety problem is not believed to be
exploitable, but we report most network-reachable memory faults as
security bugs.
* sshd(8): fix a pre-authentication double-free memory fault
introduced in OpenSSH 9.1. This is not believed to be exploitable,
and it occurs in the unprivileged pre-auth process that is
subject to chroot(2) and is further sandboxed on most major
platforms.
* ssh(8): in OpenSSH releases after 8.7, the PermitRemoteOpen option
would ignore its first argument unless it was one of the special
keywords "any" or "none", causing the permission list to fail open
if only one permission was specified. bz3515
* ssh(1): if the CanonicalizeHostname and CanonicalizePermittedCNAMEs
options were enabled, and the system/libc resolver did not check
that names in DNS responses were valid, then use of these options
could allow an attacker with control of DNS to include invalid
characters (possibly including wildcards) in names added to
known_hosts files when they were updated. These names would still
have to match the CanonicalizePermittedCNAMEs allow-list, so
practical exploitation appears unlikely.
Potentially-incompatible changes
* ssh(1): add a new EnableEscapeCommandline ssh_config(5) option that
controls whether the client-side ~C escape sequence that provides a
command-line is available. Among other things, the ~C command-line
could be used to add additional port-forwards at runtime.
This option defaults to "no", disabling the ~C command-line that
was previously enabled by default. Turning off the command-line
allows platforms that support sandboxing of the ssh(1) client
(currently only OpenBSD) to use a stricter default sandbox policy.
New features
* sshd(8): add support for channel inactivity timeouts via a new
sshd_config(5) ChannelTimeout directive. This allows channels that
have not seen traffic in a configurable interval to be
automatically closed. Different timeouts may be applied to session,
X11, agent and TCP forwarding channels.
* sshd(8): add a sshd_config UnusedConnectionTimeout option to
terminate client connections that have no open channels for a
length of time. This complements the ChannelTimeout option above.
* sshd(8): add a -V (version) option to sshd like the ssh client has.
* ssh(1): add a "Host" line to the output of ssh -G showing the
original hostname argument. bz3343
* scp(1), sftp(1): add a -X option to both scp(1) and sftp(1) to
allow control over some SFTP protocol parameters: the copy buffer
length and the number of in-flight requests, both of which are used
during upload/download. Previously these could be controlled in
sftp(1) only. This makes them available in both SFTP protocol
clients using the same option character sequence.
* ssh-keyscan(1): allow scanning of complete CIDR address ranges,
e.g. "ssh-keyscan 192.168.0.0/24". If a CIDR range is passed, then
it will be expanded to all possible addresses in the range
including the all-0s and all-1s addresses. bz#976
* ssh(1): support dynamic remote port forwarding in escape
command-line's -R processing. bz#3499
Bugfixes
* ssh(1): when restoring non-blocking mode to stdio fds, restore
exactly the flags that ssh started with and don't just clobber them
with zero, as this could also remove the append flag from the set.
bz3523
* ssh(1): avoid printf("%s", NULL) if using UserKnownHostsFile=none
and a hostkey in one of the system known hosts file changes.
* scp(1): switch scp from using pipes to a socket-pair for
communication with its ssh sub-processes, matching how sftp(1)
operates.
* sshd(8): clear signal mask early in main(); sshd may have been
started with one or more signals masked (sigprocmask(2) is not
cleared on fork/exec) and this could interfere with various things,
e.g. the login grace timer. Execution environments that fail to
clear the signal mask before running sshd are clearly broken, but
apparently they do exist.
* ssh(1): warn if no host keys for hostbased auth can be loaded.
* sshd(8): Add server debugging for hostbased auth that is queued and
sent to the client after successful authentication, but also logged
to assist in diagnosis of HostbasedAuthentication problems. bz3507
* ssh(1): document use of the IdentityFile option as being usable to
list public keys as well as private keys. GHPR352
* sshd(8): check for and disallow MaxStartups values less than or
equal to zero during config parsing, rather than failing later at
runtime. bz3489
* ssh-keygen(1): fix parsing of hex cert expiry times specified on
the command-line when acting as a CA.
* scp(1): when scp(1) is using the SFTP protocol for transport (the
default), better match scp/rcp's handling of globs that don't match
the globbed characters but do match literally (e.g. trying to
transfer a file named "foo.[1]"). Previously scp(1) in SFTP mode
would not match these pathnames but legacy scp/rcp mode would.
bz3488
* ssh-agent(1): document the "-O no-restrict-websafe" command-line
option.
* ssh(1): honour user's umask(2) if it is more restrictive then the
ssh default (022).
Portability
* sshd(8): allow writev(2) in the Linux seccomp sandbox. This seems
to be used by recent glibcs at least in some configurations during
error conditions. bz3512.
* sshd(8): simply handling of SSH_CONNECTION PAM env var, removing
global variable and checking the return value from pam_putenv.
bz3508
* sshd(8): disable SANDBOX_SECCOMP_FILTER_DEBUG that was mistakenly
enabled during the OpenSSH 9.1 release cycle.
* misc: update autotools and regenerate the config files using the
latest autotools
* all: use -fzero-call-used-regs=used on clang 15 instead of
-fzero-call-used-reg=all, as some versions of clang 15 have
miscompile code when it was enabled. bz3475
* sshd(8): defer PRNG seeding until after the initial closefrom(2)
call. PRNG seeding will initialize OpenSSL, and some engine
providers (e.g. Intel's QAT) will open descriptors for their own
use that closefrom(2) could clobber. bz3483
* misc: in the poll(2)/ppoll(2) compatibility code, avoid assuming
the layout of fd_set.
* sftp-server(8), ssh-agent(1): fix ptrace(2) disabling on older
FreeBSD kernels. Some versions do not support using id 0 to refer
to the current PID for procctl, so try again with getpid()
explicitly before failing.
* configure.ac: fix -Wstrict-prototypes in configure test code.
Clang 16 now warns on this and legacy prototypes will be removed
in C23. GHPR355
* configure.ac: fix setres*id checks to work with clang-16. glibc
has the prototypes for setresuid behind _GNU_SOURCE, and clang 16
will error out on implicit function definitions. bz3497
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available from the mirror sites:
https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/RELEASE_KEY.asc
Reporting Bugs:
OpenSSH 9.1 was released on 2022-10-04. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
https://www.openssh.com/donations.html
Changes since OpenSSH 9.0
This release is focused on bug fixing.
Security
This release contains fixes for three minor memory safety problems.
None are believed to be exploitable, but we report most memory safety
problems as potential security vulnerabilities out of caution.
* ssh-keyscan(1): fix a one-byte overflow in SSH- banner processing.
Reported by Qualys
* ssh-keygen(1): double free() in error path of file hashing step in
signing/verify code; GHPR333
* ssh-keysign(8): double-free in error path introduced in openssh-8.9
Potentially-incompatible changes
* The portable OpenSSH project now signs commits and release tags
using git's recent SSH signature support. The list of developer
signing keys is included in the repository as .git_allowed_signers
and is cross-signed using the PGP key that is still used to sign
release artifacts:
https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/RELEASE_KEY.asc
* ssh(1), sshd(8): SetEnv directives in ssh_config and sshd_config
are now first-match-wins to match other directives. Previously
if an environment variable was multiply specified the last set
value would have been used. bz3438
* ssh-keygen(8): ssh-keygen -A (generate all default host key types)
will no longer generate DSA keys, as these are insecure and have
not been used by default for some years.
New features
* ssh(1), sshd(8): add a RequiredRSASize directive to set a minimum
RSA key length. Keys below this length will be ignored for user
authentication and for host authentication in sshd(8).
ssh(1) will terminate a connection if the server offers an RSA key
that falls below this limit, as the SSH protocol does not include
the ability to retry a failed key exchange.
* sftp-server(8): add a "users-groups-by-id@openssh.com" extension
request that allows the client to obtain user/group names that
correspond to a set of uids/gids.
* sftp(1): use "users-groups-by-id@openssh.com" sftp-server
extension (when available) to fill in user/group names for
directory listings.
* sftp-server(8): support the "home-directory" extension request
defined in draft-ietf-secsh-filexfer-extensions-00. This overlaps
a bit with the existing "expand-path@openssh.com", but some other
clients support it.
* ssh-keygen(1), sshd(8): allow certificate validity intervals,
sshsig verification times and authorized_keys expiry-time options
to accept dates in the UTC time zone in addition to the default
of interpreting them in the system time zone. YYYYMMDD and
YYMMDDHHMM[SS] dates/times will be interpreted as UTC if suffixed
with a 'Z' character.
Also allow certificate validity intervals to be specified in raw
seconds-since-epoch as hex value, e.g. -V 0x1234:0x4567890. This
is intended for use by regress tests and other tools that call
ssh-keygen as part of a CA workflow. bz3468
* sftp(1): allow arguments to the sftp -D option, e.g. sftp -D
"/usr/libexec/sftp-server -el debug3"
* ssh-keygen(1): allow the existing -U (use agent) flag to work
with "-Y sign" operations, where it will be interpreted to require
that the private keys is hosted in an agent; bz3429
Bugfixes
* ssh-keygen(1): implement the "verify-required" certificate option.
This was already documented when support for user-verified FIDO
keys was added, but the ssh-keygen(1) code was missing.
* ssh-agent(1): hook up the restrict_websafe command-line flag;
previously the flag was accepted but never actually used.
* sftp(1): improve filename tab completions: never try to complete
names to non-existent commands, and better match the completion
type (local or remote filename) against the argument position
being completed.
* ssh-keygen(1), ssh(1), ssh-agent(1): several fixes to FIDO key
handling, especially relating to keys that request
user-verification. These should reduce the number of unnecessary
PIN prompts for keys that support intrinsic user verification.
GHPR302, GHPR329
* ssh-keygen(1): when enrolling a FIDO resident key, check if a
credential with matching application and user ID strings already
exists and, if so, prompt the user for confirmation before
overwriting the credential. GHPR329
* sshd(8): improve logging of errors when opening authorized_keys
files. bz2042
* ssh(1): avoid multiplexing operations that could cause SIGPIPE from
causing the client to exit early. bz3454
* ssh_config(5), sshd_config(5): clarify that the RekeyLimit
directive applies to both transmitted and received data. GHPR328
* ssh-keygen(1): avoid double fclose() in error path.
* sshd(8): log an error if pipe() fails while accepting a
connection. bz3447
* ssh(1), ssh-keygen(1): fix possible NULL deref when built without
FIDO support. bz3443
* ssh-keyscan(1): add missing *-sk types to ssh-keyscan manpage.
GHPR294.
* sshd(8): ensure that authentication passwords are cleared from
memory in error paths. GHPR286
* ssh(1), ssh-agent(1): avoid possibility of notifier code executing
kill(-1). GHPR286
* ssh_config(5): note that the ProxyJump directive also accepts the
same tokens as ProxyCommand. GHPR305.
* scp(1): do not ftruncate(3) files early when in sftp mode. The
previous behaviour of unconditionally truncating the destination
file would cause "scp ~/foo localhost:foo" and the reverse
"scp localhost:foo ~/foo" to delete all the contents of their
destination. bz3431
* ssh-keygen(1): improve error message when 'ssh-keygen -Y sign' is
unable to load a private key; bz3429
* sftp(1), scp(1): when performing operations that glob(3) a remote
path, ensure that the implicit working directory used to construct
that path escapes glob(3) characters. This prevents glob characters
from being processed in places they shouldn't, e.g. "cd /tmp/a*/",
"get *.txt" should have the get operation treat the path "/tmp/a*"
literally and not attempt to expand it.
* ssh(1), sshd(8): be stricter in which characters will be accepted
in specifying a mask length; allow only 0-9. GHPR278
* ssh-keygen(1): avoid printing hash algorithm twice when dumping a
KRL
* ssh(1), sshd(8): continue running local I/O for open channels
during SSH transport rekeying. This should make ~-escapes work in
the client (e.g. to exit) if the connection happened to have
stalled during a rekey event.
* ssh(1), sshd(8): avoid potential poll() spin during rekeying
* Further hardening for sshbuf internals: disallow "reparenting" a
hierarchical sshbuf and zero the entire buffer if reallocation
fails. GHPR287
Portability
* ssh(1), ssh-keygen(1), sshd(8): automatically enable the built-in
FIDO security key support if libfido2 is found and usable, unless
--without-security-key-builtin was requested.
* ssh(1), ssh-keygen(1), sshd(8): many fixes to make the WinHello
FIDO device usable on Cygwin. The windows://hello FIDO device will
be automatically used by default on this platform unless requested
otherwise, or when probing resident FIDO credentials (an operation
not currently supported by WinHello).
* Portable OpenSSH: remove workarounds for obsolete and unsupported
versions of OpenSSL libcrypto. In particular, this release removes
fallback support for OpenSSL that lacks AES-CTR or AES-GCM.
Those AES cipher modes were added to OpenSSL prior to the minimum
version currently supported by OpenSSH, so this is not expected to
impact any currently supported configurations.
* sshd(8): fix SANDBOX_SECCOMP_FILTER_DEBUG on current Linux/glibc
* All: resync and clean up internal CSPRNG code.
* scp(1), sftp(1), sftp-server(8): avoid linking these programs with
unnecessary libraries. They are no longer linked against libz and
libcrypto. This may be of benefit to space constrained systems
using any of those components in isolation.
* sshd(8): add AUDIT_ARCH_PPC to supported seccomp sandbox
architectures.
* configure: remove special casing of crypt(). configure will no
longer search for crypt() in libcrypto, as it was removed from
there years ago. configure will now only search libc and libcrypt.
* configure: refuse to use OpenSSL 3.0.4 due to potential RCE in its
RSA implementation (CVE-2022-2274) on x86_64.
* All: request 1.1x API compatibility for OpenSSL >=3.x; GHPR#322
* ssh(1), ssh-keygen(1), sshd(8): fix a number of missing includes
required by the XMSS code on some platforms.
* sshd(8): cache timezone data in capsicum sandbox.
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available from the mirror sites:
https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/RELEASE_KEY.asc
Reporting Bugs:
OpenSSH 9.0 was released on 2022-04-08. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
https://www.openssh.com/donations.html
Changes since OpenSSH 8.9
This release is focused on bug fixing.
Potentially-incompatible changes
This release switches scp(1) from using the legacy scp/rcp protocol
to using the SFTP protocol by default.
Legacy scp/rcp performs wildcard expansion of remote filenames (e.g.
"scp host:* .") through the remote shell. This has the side effect of
requiring double quoting of shell meta-characters in file names
included on scp(1) command-lines, otherwise they could be interpreted
as shell commands on the remote side.
This creates one area of potential incompatibility: scp(1) when using
the SFTP protocol no longer requires this finicky and brittle quoting,
and attempts to use it may cause transfers to fail. We consider the
removal of the need for double-quoting shell characters in file names
to be a benefit and do not intend to introduce bug-compatibility for
legacy scp/rcp in scp(1) when using the SFTP protocol.
Another area of potential incompatibility relates to the use of remote
paths relative to other user's home directories, for example -
"scp host:~user/file /tmp". The SFTP protocol has no native way to
expand a ~user path. However, sftp-server(8) in OpenSSH 8.7 and later
support a protocol extension "expand-path@openssh.com" to support
this.
In case of incompatibility, the scp(1) client may be instructed to use
the legacy scp/rcp using the -O flag.
New features
* ssh(1), sshd(8): use the hybrid Streamlined NTRU Prime + x25519 key
exchange method by default ("sntrup761x25519-sha512@openssh.com").
The NTRU algorithm is believed to resist attacks enabled by future
quantum computers and is paired with the X25519 ECDH key exchange
(the previous default) as a backstop against any weaknesses in
NTRU Prime that may be discovered in the future. The combination
ensures that the hybrid exchange offers at least as good security
as the status quo.
We are making this change now (i.e. ahead of cryptographically-
relevant quantum computers) to prevent "capture now, decrypt
later" attacks where an adversary who can record and store SSH
session ciphertext would be able to decrypt it once a sufficiently
advanced quantum computer is available.
* sftp-server(8): support the "copy-data" extension to allow server-
side copying of files/data, following the design in
draft-ietf-secsh-filexfer-extensions-00. bz2948
* sftp(1): add a "cp" command to allow the sftp client to perform
server-side file copies.
Bugfixes
* ssh(1), sshd(8): upstream: fix poll(2) spin when a channel's output
fd closes without data in the channel buffer. bz3405 and bz3411
* sshd(8): pack pollfd array in server listen/accept loop. Could
cause the server to hang/spin when MaxStartups > RLIMIT_NOFILE
* ssh-keygen(1): avoid NULL deref via the find-principals and
check-novalidate operations. bz3409 and GHPR#307 respectively.
* scp(1): fix a memory leak in argument processing. bz3404
* sshd(8): don't try to resolve ListenAddress directives in the sshd
re-exec path. They are unused after re-exec and parsing errors
(possible for example if the host's network configuration changed)
could prevent connections from being accepted.
* sshd(8): when refusing a public key authentication request from a
client for using an unapproved or unsupported signature algorithm
include the algorithm name in the log message to make debugging
easier.
Portability
* sshd(8): refactor platform-specific locked account check, fixing
an incorrect free() on platforms with both libiaf and shadow
passwords (probably only Unixware) GHPR#284,
* ssh(1), sshd(8): Fix possible integer underflow in scan_scaled(3)
parsing of K/M/G/etc quantities. bz#3401.
* sshd(8): provide killpg implementation (mostly for Tandem NonStop)
GHPR#301.
* Check for missing ftruncate prototype. GHPR#301
* sshd(8): default to not using sandbox when cross compiling. On most
systems poll(2) does not work when the number of FDs is reduced
with setrlimit, so assume it doesn't when cross compiling and we
can't run the test. bz#3398.
* sshd(8): allow ppoll_time64 in seccomp sandbox. Should fix sandbox
violations on some (at least i386 and armhf) 32bit Linux platforms.
bz#3396.
* Improve detection of -fzero-call-used-regs=all support in
configure script.
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available from the mirror sites:
https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/RELEASE_KEY.asc
Please note that the OpenPGP key used to sign releases has been
rotated for this release. The new key has been signed by the previous
key to provide continuity.
Reporting Bugs:
OpenSSH 8.9 was released on 2022-02-23. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
https://www.openssh.com/donations.html
Future deprecation notice
A near-future release of OpenSSH will switch scp(1) from using the
legacy scp/rcp protocol to using SFTP by default.
Legacy scp/rcp performs wildcard expansion of remote filenames (e.g.
"scp host:* .") through the remote shell. This has the side effect of
requiring double quoting of shell meta-characters in file names
included on scp(1) command-lines, otherwise they could be interpreted
as shell commands on the remote side.
This creates one area of potential incompatibility: scp(1) when using
the SFTP protocol no longer requires this finicky and brittle quoting,
and attempts to use it may cause transfers to fail. We consider the
removal of the need for double-quoting shell characters in file names
to be a benefit and do not intend to introduce bug-compatibility for
legacy scp/rcp in scp(1) when using the SFTP protocol.
Another area of potential incompatibility relates to the use of remote
paths relative to other user's home directories, for example -
"scp host:~user/file /tmp". The SFTP protocol has no native way to
expand a ~user path. However, sftp-server(8) in OpenSSH 8.7 and later
support a protocol extension "expand-path@openssh.com" to support
this.
Security Near Miss
* sshd(8): fix an integer overflow in the user authentication path
that, in conjunction with other logic errors, could have yielded
unauthenticated access under difficult to exploit conditions.
This situation is not exploitable because of independent checks in
the privilege separation monitor. Privilege separation has been
enabled by default in since openssh-3.2.2 (released in 2002) and
has been mandatory since openssh-7.5 (released in 2017). Moreover,
portable OpenSSH has used toolchain features available in most
modern compilers to abort on signed integer overflow since
openssh-6.5 (released in 2014).
Thanks to Malcolm Stagg for finding and reporting this bug.
Potentially-incompatible changes
* sshd(8), portable OpenSSH only: this release removes in-built
support for MD5-hashed passwords. If you require these on your
system then we recommend linking against libxcrypt or similar.
* This release modifies the FIDO security key middleware interface
and increments SSH_SK_VERSION_MAJOR.
Changes since OpenSSH 8.8
This release includes a number of new features.
New features
* ssh(1), sshd(8), ssh-add(1), ssh-agent(1): add a system for
restricting forwarding and use of keys added to ssh-agent(1)
A detailed description of the feature is available at
https://www.openssh.com/agent-restrict.html and the protocol
extensions are documented in the PROTOCOL and PROTOCOL.agent
files in the source release.
* ssh(1), sshd(8): add the sntrup761x25519-sha512@openssh.com hybrid
ECDH/x25519 + Streamlined NTRU Prime post-quantum KEX to the
default KEXAlgorithms list (after the ECDH methods but before the
prime-group DH ones). The next release of OpenSSH is likely to
make this key exchange the default method.
* ssh-keygen(1): when downloading resident keys from a FIDO token,
pass back the user ID that was used when the key was created and
append it to the filename the key is written to (if it is not the
default). Avoids keys being clobbered if the user created multiple
resident keys with the same application string but different user
IDs.
* ssh-keygen(1), ssh(1), ssh-agent(1): better handling for FIDO keys
on tokens that provide user verification (UV) on the device itself,
including biometric keys, avoiding unnecessary PIN prompts.
* ssh-keygen(1): add "ssh-keygen -Y match-principals" operation to
perform matching of principals names against an allowed signers
file. To be used towards a TOFU model for SSH signatures in git.
* ssh-add(1), ssh-agent(1): allow pin-required FIDO keys to be added
to ssh-agent(1). $SSH_ASKPASS will be used to request the PIN at
authentication time.
* ssh-keygen(1): allow selection of hash at sshsig signing time
(either sha512 (default) or sha256).
* ssh(1), sshd(8): read network data directly to the packet input
buffer instead of indirectly via a small stack buffer. Provides a
modest performance improvement.
* ssh(1), sshd(8): read data directly to the channel input buffer,
providing a similar modest performance improvement.
* ssh(1): extend the PubkeyAuthentication configuration directive to
accept yes|no|unbound|host-bound to allow control over one of the
protocol extensions used to implement agent-restricted keys.
Bugfixes
* sshd(8): document that CASignatureAlgorithms, ExposeAuthInfo and
PubkeyAuthOptions can be used in a Match block. PR#277.
* sshd(8): fix possible string truncation when constructing paths to
.rhosts/.shosts files with very long user home directory names.
* ssh-keysign(1): unbreak for KEX algorithms that use SHA384/512
exchange hashes
* ssh(1): don't put the TTY into raw mode when SessionType=none,
avoids ^C being unable to kill such a session. bz3360
* scp(1): fix some corner-case bugs in SFTP-mode handling of
~-prefixed paths.
* ssh(1): unbreak hostbased auth using RSA keys. Allow ssh(1) to
select RSA keys when only RSA/SHA2 signature algorithms are
configured (this is the default case). Previously RSA keys were
not being considered in the default case.
* ssh-keysign(1): make ssh-keysign use the requested signature
algorithm and not the default for the key type. Part of unbreaking
hostbased auth for RSA/SHA2 keys.
* ssh(1): stricter UpdateHostkey signature verification logic on
the client- side. Require RSA/SHA2 signatures for RSA hostkeys
except when RSA/SHA1 was explicitly negotiated during initial
KEX; bz3375
* ssh(1), sshd(8): fix signature algorithm selection logic for
UpdateHostkeys on the server side. The previous code tried to
prefer RSA/SHA2 for hostkey proofs of RSA keys, but missed some
cases. This will use RSA/SHA2 signatures for RSA keys if the
client proposed these algorithms in initial KEX. bz3375
* All: convert all uses of select(2)/pselect(2) to poll(2)/ppoll(2).
This includes the mainloops in ssh(1), ssh-agent(1), ssh-agent(1)
and sftp-server(8), as well as the sshd(8) listen loop and all
other FD read/writability checks. On platforms with missing or
broken poll(2)/ppoll(2) syscalls a select(2)-based compat shim is
available.
* ssh-keygen(1): the "-Y find-principals" command was verifying key
validity when using ca certs but not with simple key lifetimes
within the allowed signers file.
* ssh-keygen(1): make sshsig verify-time argument parsing optional
* sshd(8): fix truncation in rhosts/shosts path construction.
* ssh(1), ssh-agent(1): avoid xmalloc(0) for PKCS#11 keyid for ECDSA
keys (we already did this for RSA keys). Avoids fatal errors for
PKCS#11 libraries that return empty keyid, e.g. Microchip ATECC608B
"cryptoauthlib"; bz#3364
* ssh(1), ssh-agent(1): improve the testing of credentials against
inserted FIDO: ask the token whether a particular key belongs to
it in cases where the token supports on-token user-verification
(e.g. biometrics) rather than just assuming that it will accept it.
Will reduce spurious "Confirm user presence" notifications for key
handles that relate to FIDO keys that are not currently inserted in at
least some cases. bz3366
* ssh(1), sshd(8): correct value for IPTOS_DSCP_LE. It needs to
allow for the preceding two ECN bits. bz#3373
* ssh-keygen(1): add missing -O option to usage() for the "-Y sign"
option.
* ssh-keygen(1): fix a NULL deref when using the find-principals
function, when matching an allowed_signers line that contains a
namespace restriction, but no restriction specified on the
command-line
* ssh-agent(1): fix memleak in process_extension(); oss-fuzz
issue #42719
* ssh(1): suppress "Connection to xxx closed" messages when LogLevel
is set to "error" or above. bz3378
* ssh(1), sshd(8): use correct zlib flags when inflate(3)-ing
compressed packet data. bz3372
* scp(1): when recursively transferring files in SFTP mode, create the
destination directory if it doesn't already exist to match scp(1) in
legacy RCP mode behaviour.
* scp(1): many improvements in error message consistency between scp(1)
in SFTP mode vs legacy RCP mode.
* sshd(8): fix potential race in SIGTERM handling PR#289
* ssh(1), ssh(8): since DSA keys are deprecated, move them to the
end of the default list of public keys so that they will be tried
last. PR#295
* ssh-keygen(1): allow 'ssh-keygen -Y find-principals' to match
wildcard principals in allowed_signers files
Portability
* ssh(1), sshd(8): don't trust closefrom(2) on Linux. glibc's
implementation does not work in a chroot when the kernel does not
have close_range(2). It tries to read from /proc/self/fd and when
that fails dies with an assertion of sorts. Instead, call
close_range(2) directly from our compat code and fall back if
that fails. bz#3349,
* OS X poll(2) is broken; use compat replacement. For character-
special devices like /dev/null, Darwin's poll(2) returns POLLNVAL
when polled with POLLIN. Apparently this is Apple bug 3710161 -
not public but a websearch will find other OSS projects
rediscovering it periodically since it was first identified in
2005.
* Correct handling of exceptfds/POLLPRI in our select(2)-based
poll(2)/ppoll(2) compat implementation.
* Cygwin: correct checking of mbstowcs() return value.
* Add a basic SECURITY.md that refers people to the openssh.com
website.
* Enable additional compiler warnings and toolchain hardening flags,
including -Wbitwise-instead-of-logical, -Wmisleading-indentation,
-fzero-call-used-regs and -ftrivial-auto-var-init.
* HP/UX. Use compat getline(3) on HP-UX 10.x, where the libc version
is not reliable.
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available from the mirror sites:
https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/RELEASE_KEY.asc
Please note that the OpenPGP key used to sign releases has been
rotated for this release. The new key has been signed by the previous
key to provide continuity.
Reporting Bugs:
OpenSSH 8.8 was released on 2021-09-26. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
https://www.openssh.com/donations.html
Future deprecation notice
A near-future release of OpenSSH will switch scp(1) from using the
legacy scp/rcp protocol to using SFTP by default.
Legacy scp/rcp performs wildcard expansion of remote filenames (e.g.
"scp host:* .") through the remote shell. This has the side effect of
requiring double quoting of shell meta-characters in file names
included on scp(1) command-lines, otherwise they could be interpreted
as shell commands on the remote side.
This creates one area of potential incompatibility: scp(1) when using
the SFTP protocol no longer requires this finicky and brittle quoting,
and attempts to use it may cause transfers to fail. We consider the
removal of the need for double-quoting shell characters in file names
to be a benefit and do not intend to introduce bug- compatibility for
legacy scp/rcp in scp(1) when using the SFTP protocol.
Another area of potential incompatibility relates to the use of remote
paths relative to other user's home directories, for example -
"scp host:~user/file /tmp". The SFTP protocol has no native way to
expand a ~user path. However, sftp-server(8) in OpenSSH 8.7 and later
support a protocol extension "expand-path@openssh.com" to support
this.
Security
sshd(8) from OpenSSH 6.2 through 8.7 failed to correctly initialise
supplemental groups when executing an AuthorizedKeysCommand or
AuthorizedPrincipalsCommand, where a AuthorizedKeysCommandUser or
AuthorizedPrincipalsCommandUser directive has been set to run the
command as a different user. Instead these commands would inherit
the groups that sshd(8) was started with.
Depending on system configuration, inherited groups may allow
AuthorizedKeysCommand/AuthorizedPrincipalsCommand helper programs to
gain unintended privilege.
Neither AuthorizedKeysCommand nor AuthorizedPrincipalsCommand are
enabled by default in sshd_config(5).
Potentially-incompatible changes
This release disables RSA signatures using the SHA-1 hash algorithm
by default. This change has been made as the SHA-1 hash algorithm is
cryptographically broken, and it is possible to create chosen-prefix
hash collisions for <USD$50K [1]
For most users, this change should be invisible and there is
no need to replace ssh-rsa keys. OpenSSH has supported RFC8332
RSA/SHA-256/512 signatures since release 7.2 and existing ssh-rsa keys
will automatically use the stronger algorithm where possible.
Incompatibility is more likely when connecting to older SSH
implementations that have not been upgraded or have not closely tracked
improvements in the SSH protocol. For these cases, it may be necessary
to selectively re-enable RSA/SHA1 to allow connection and/or user
authentication via the HostkeyAlgorithms and PubkeyAcceptedAlgorithms
options. For example, the following stanza in ~/.ssh/config will enable
RSA/SHA1 for host and user authentication for a single destination host:
Host old-host
HostkeyAlgorithms +ssh-rsa
PubkeyAcceptedAlgorithms +ssh-rsa
We recommend enabling RSA/SHA1 only as a stopgap measure until legacy
implementations can be upgraded or reconfigured with another key type
(such as ECDSA or Ed25519).
[1] "SHA-1 is a Shambles: First Chosen-Prefix Collision on SHA-1 and
Application to the PGP Web of Trust" Leurent, G and Peyrin, T
(2020) https://eprint.iacr.org/2020/014.pdf
Changes since OpenSSH 8.7
This release is motivated primarily by the above deprecation and
security fix.
New features
* ssh(1): allow the ssh_config(5) CanonicalizePermittedCNAMEs
directive to accept a "none" argument to specify the default
behaviour.
Bugfixes
* scp(1): when using the SFTP protocol, continue transferring files
after a transfer error occurs, better matching original scp/rcp
behaviour.
* ssh(1): fixed a number of memory leaks in multiplexing,
* ssh-keygen(1): avoid crash when using the -Y find-principals
command.
* A number of documentation and manual improvements, including
bz#3340, PR#139, PR#215, PR#241, PR#257
Portability
* ssh-agent(1): on FreeBSD, use procctl to disable ptrace(2)
* ssh(1)/sshd(8): some fixes to the pselect(2) replacement
compatibility code. bz#3345
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available from the mirror sites:
https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/RELEASE_KEY.asc
Please note that the OpenPGP key used to sign releases has been
rotated for this release. The new key has been signed by the previous
key to provide continuity.
Reporting Bugs:
OpenSSH 8.7 was released on 2021-08-20. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
https://www.openssh.com/donations.html
Imminent deprecation notice
OpenSSH will disable the ssh-rsa signature scheme by default in the
next release.
In the SSH protocol, the "ssh-rsa" signature scheme uses the SHA-1
hash algorithm in conjunction with the RSA public key algorithm.
It is now possible[1] to perform chosen-prefix attacks against the
SHA-1 algorithm for less than USD$50K.
Note that the deactivation of "ssh-rsa" signatures does not necessarily
require cessation of use for RSA keys. In the SSH protocol, keys may be
capable of signing using multiple algorithms. In particular, "ssh-rsa"
keys are capable of signing using "rsa-sha2-256" (RSA/SHA256),
"rsa-sha2-512" (RSA/SHA512) and "ssh-rsa" (RSA/SHA1). Only the last of
these is being turned off by default.
This algorithm is unfortunately still used widely despite the
existence of better alternatives, being the only remaining public key
signature algorithm specified by the original SSH RFCs that is still
enabled by default.
The better alternatives include:
* The RFC8332 RSA SHA-2 signature algorithms rsa-sha2-256/512. These
algorithms have the advantage of using the same key type as
"ssh-rsa" but use the safe SHA-2 hash algorithms. These have been
supported since OpenSSH 7.2 and are already used by default if the
client and server support them.
* The RFC8709 ssh-ed25519 signature algorithm. It has been supported
in OpenSSH since release 6.5.
* The RFC5656 ECDSA algorithms: ecdsa-sha2-nistp256/384/521. These
have been supported by OpenSSH since release 5.7.
To check whether a server is using the weak ssh-rsa public key
algorithm, for host authentication, try to connect to it after
removing the ssh-rsa algorithm from ssh(1)'s allowed list:
ssh -oHostKeyAlgorithms=-ssh-rsa user@host
If the host key verification fails and no other supported host key
types are available, the server software on that host should be
upgraded.
OpenSSH recently enabled the UpdateHostKeys option by default to
assist the client by automatically migrating to better algorithms.
[1] "SHA-1 is a Shambles: First Chosen-Prefix Collision on SHA-1 and
Application to the PGP Web of Trust" Leurent, G and Peyrin, T
(2020) https://eprint.iacr.org/2020/014.pdf
Potentially-incompatible changes
This release includes a number of changes that may affect existing
configurations:
* scp(1): this release changes the behaviour of remote to remote
copies (e.g. "scp host-a:/path host-b:") to transfer through the
local host by default. This was previously available via the -3
flag. This mode avoids the need to expose credentials on the
origin hop, avoids triplicate interpretation of filenames by the
shell (by the local system, the copy origin and the destination)
and, in conjunction with the SFTP support for scp(1) mentioned
below, allows use of all authentication methods to the remote
hosts (previously, only non-interactive methods could be used).
A -R flag has been added to select the old behaviour.
* ssh(1)/sshd(8): both the client and server are now using a
stricter configuration file parser. The new parser uses more
shell-like rules for quotes, space and escape characters. It is
also more strict in rejecting configurations that include options
lacking arguments. Previously some options (e.g. DenyUsers) could
appear on a line with no subsequent arguments. This release will
reject such configurations. The new parser will also reject
configurations with unterminated quotes and multiple '='
characters after the option name.
* ssh(1): when using SSHFP DNS records for host key verification,
ssh(1) will verify all matching records instead of just those
with the specific signature type requested. This may cause host
key verification problems if stale SSHFP records of a different
or legacy signature type exist alongside other records for a
particular host. bz#3322
* ssh-keygen(1): when generating a FIDO key and specifying an
explicit attestation challenge (using -Ochallenge), the challenge
will now be hashed by the builtin security key middleware. This
removes the (undocumented) requirement that challenges be exactly
32 bytes in length and matches the expectations of libfido2.
* sshd(8): environment="..." directives in authorized_keys files are
now first-match-wins and limited to 1024 discrete environment
variable names.
Changes since OpenSSH 8.6
This release contains a mix of new features and bug-fixes.
New features
scp(1): experimental support for transfers using the SFTP protocol
as a replacement for the venerable SCP/RCP protocol that it has
traditionally used. SFTP offers more predictable filename handling
and does not require expansion of glob(3) patterns via the shell
on the remote side.
SFTP support may be enabled via a temporary scp -s flag. It is
intended for SFTP to become the default transfer mode in the
near future, at which time the -s flag will be removed. The -O
flag exists to force use of the original SCP/RCP protocol for
cases where SFTP may be unavailable or incompatible.
sftp-server(8): add a protocol extension to support expansion of
~/ and ~user/ prefixed paths. This was added to support these
paths when used by scp(1) while in SFTP mode.
ssh(1): add a ForkAfterAuthentication ssh_config(5) counterpart to
the ssh(1) -f flag. GHPR#231
ssh(1): add a StdinNull directive to ssh_config(5) that allows the
config file to do the same thing as -n does on the ssh(1) command-
line. GHPR#231
ssh(1): add a SessionType directive to ssh_config, allowing the
configuration file to offer equivalent control to the -N (no
session) and -s (subsystem) command-line flags. GHPR#231
ssh-keygen(1): allowed signers files used by ssh-keygen(1)
signatures now support listing key validity intervals alongside
they key, and ssh-keygen(1) can optionally check during signature
verification whether a specified time falls inside this interval.
This feature is intended for use by git to support signing and
verifying objects using ssh keys.
ssh-keygen(8): support printing of the full public key in a sshsig
signature via a -Oprint-pubkey flag.
Bugfixes
* ssh(1)/sshd(8): start time-based re-keying exactly on schedule in
the client and server mainloops. Previously the re-key timeout
could expire but re-keying would not start until a packet was sent
or received, causing a spin in select() if the connection was
quiescent.
* ssh-keygen(1): avoid Y2038 problem in printing certificate
validity lifetimes. Dates past 2^31-1 seconds since epoch were
displayed incorrectly on some platforms. bz#3329
* scp(1): allow spaces to appear in usernames for local to remote
and scp -3 remote to remote copies. bz#1164
* ssh(1)/sshd(8): remove references to ChallengeResponseAuthentication
in favour of KbdInteractiveAuthentication. The former is what was in
SSHv1, the latter is what is in SSHv2 (RFC4256) and they were
treated as somewhat but not entirely equivalent. We retain the old
name as a deprecated alias so configuration files continue to work
as well as a reference in the man page for people looking for it.
bz#3303
* ssh(1)/ssh-add(1)/ssh-keygen(1): fix decoding of X.509 subject name
when extracting a key from a PKCS#11 certificate. bz#3327
* ssh(1): restore blocking status on stdio fds before close. ssh(1)
needs file descriptors in non-blocking mode to operate but it was
not restoring the original state on exit. This could cause
problems with fds shared with other programs via the shell,
bz#3280 and GHPR#246
* ssh(1)/sshd(8): switch both client and server mainloops from
select(3) to pselect(3). Avoids race conditions where a signal
may arrive immediately before select(3) and not be processed until
an event fires. bz#2158
* ssh(1): sessions started with ControlPersist were incorrectly
executing a shell when the -N (no shell) option was specified.
bz#3290
* ssh(1): check if IPQoS or TunnelDevice are already set before
overriding. Prevents values in config files from overriding values
supplied on the command line. bz#3319
* ssh(1): fix debug message when finding a private key to match a
certificate being attempted for user authentication. Previously it
would print the certificate's path, whereas it was supposed to be
showing the private key's path. GHPR#247
* sshd(8): match host certificates against host public keys, not
private keys. Allows use of certificates with private keys held in
a ssh-agent. bz#3524
* ssh(1): add a workaround for a bug in OpenSSH 7.4 sshd(8), which
allows RSA/SHA2 signatures for public key authentication but fails
to advertise this correctly via SSH2_MSG_EXT_INFO. This causes
clients of these server to incorrectly match
PubkeyAcceptedAlgorithmse and potentially refuse to offer valid
keys. bz#3213
* sftp(1)/scp(1): degrade gracefully if a sftp-server offers the
limits@openssh.com extension but fails when the client tries to
invoke it. bz#3318
* ssh(1): allow ssh_config SetEnv to override $TERM, which is
otherwise handled specially by the protocol. Useful in ~/.ssh/config
to set TERM to something generic (e.g. "xterm" instead of
"xterm-256color") for destinations that lack terminfo entries.
* sftp-server(8): the limits@openssh.com extension was incorrectly
marked as an operation that writes to the filesystem, which made it
unavailable in sftp-server read-only mode. bz#3318
* ssh(1): fix SEGV in UpdateHostkeys debug() message, triggered when
the update removed more host keys than remain present.
* many manual page fixes.
Portability
* ssh(1): move closefrom() to before first malloc. When built against
tcmalloc, the closefrom() would stomp on file descriptors created
for tcmalloc's internal use. bz#3321
* sshd(8): handle GIDs > 2^31 in getgrouplist. When compiled in 32bit
mode, the getgrouplist implementation may fail for GIDs greater than
LONG_MAX.
* ssh(1): xstrdup environment variable used by ForwardAgent. bz#3328
* sshd(8): don't sigdie() in signal handler in privsep child process;
this can end up causing sandbox violations per bz3286
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available from the mirror sites:
https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/RELEASE_KEY.asc
Please note that the OpenPGP key used to sign releases has been
rotated for this release. The new key has been signed by the previous
key to provide continuity.
Reporting Bugs:
OpenSSH 8.6 was released on 2021-04-19. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
https://www.openssh.com/donations.html
Future deprecation notice
It is now possible[1] to perform chosen-prefix attacks against the
SHA-1 algorithm for less than USD$50K.
In the SSH protocol, the "ssh-rsa" signature scheme uses the SHA-1
hash algorithm in conjunction with the RSA public key algorithm.
OpenSSH will disable this signature scheme by default in the near
future.
Note that the deactivation of "ssh-rsa" signatures does not necessarily
require cessation of use for RSA keys. In the SSH protocol, keys may be
capable of signing using multiple algorithms. In particular, "ssh-rsa"
keys are capable of signing using "rsa-sha2-256" (RSA/SHA256),
"rsa-sha2-512" (RSA/SHA512) and "ssh-rsa" (RSA/SHA1). Only the last of
these is being turned off by default.
This algorithm is unfortunately still used widely despite the
existence of better alternatives, being the only remaining public key
signature algorithm specified by the original SSH RFCs that is still
enabled by default.
The better alternatives include:
* The RFC8332 RSA SHA-2 signature algorithms rsa-sha2-256/512. These
algorithms have the advantage of using the same key type as
"ssh-rsa" but use the safe SHA-2 hash algorithms. These have been
supported since OpenSSH 7.2 and are already used by default if the
client and server support them.
* The RFC8709 ssh-ed25519 signature algorithm. It has been supported
in OpenSSH since release 6.5.
* The RFC5656 ECDSA algorithms: ecdsa-sha2-nistp256/384/521. These
have been supported by OpenSSH since release 5.7.
To check whether a server is using the weak ssh-rsa public key
algorithm, for host authentication, try to connect to it after
removing the ssh-rsa algorithm from ssh(1)'s allowed list:
ssh -oHostKeyAlgorithms=-ssh-rsa user@host
If the host key verification fails and no other supported host key
types are available, the server software on that host should be
upgraded.
OpenSSH recently enabled the UpdateHostKeys option by default to assist
the client by automatically migrating to better algorithms.
[1] "SHA-1 is a Shambles: First Chosen-Prefix Collision on SHA-1 and
Application to the PGP Web of Trust" Leurent, G and Peyrin, T
(2020) https://eprint.iacr.org/2020/014.pdf
Security
* sshd(8): OpenSSH 8.5 introduced the LogVerbose keyword. When this
option was enabled with a set of patterns that activated logging
in code that runs in the low-privilege sandboxed sshd process, the
log messages were constructed in such a way that printf(3) format
strings could effectively be specified the low-privilege code.
An attacker who had successfully exploited the low-privilege
process could use this to escape OpenSSH's sandboxing and attack
the high-privilege process. Exploitation of this weakness is
highly unlikely in practice as the LogVerbose option is not
enabled by default and is typically only used for debugging. No
vulnerabilities in the low-privilege process are currently known
to exist.
Thanks to Ilja Van Sprundel for reporting this bug.
Changes since OpenSSH 8.5
This release contains mostly bug fixes.
New features
* sftp-server(8): add a new limits@openssh.com protocol extension
that allows a client to discover various server limits, including
maximum packet size and maximum read/write length.
* sftp(1): use the new limits@openssh.com extension (when available)
to select better transfer lengths in the client.
* sshd(8): Add ModuliFile keyword to sshd_config to specify the
location of the "moduli" file containing the groups for DH-GEX.
* unit tests: Add a TEST_SSH_ELAPSED_TIMES environment variable to
enable printing of the elapsed time in seconds of each test.
Bugfixes
* ssh_config(5), sshd_config(5): sync CASignatureAlgorithms lists in
manual pages with the current default. GHPR#174
* ssh(1): ensure that pkcs11_del_provider() is called before exit.
GHPR#234
* ssh(1), sshd(8): fix problems in string->argv conversion. Multiple
backslashes were not being dequoted correctly and quoted space in
the middle of a string was being incorrectly split. GHPR#223
* ssh(1): return non-zero exit status when killed by signal; bz#3281
* sftp-server(8): increase maximum SSH2_FXP_READ to match the maximum
packet size. Also handle zero-length reads that are not explicitly
banned by the spec.
Portability
* sshd(8): don't mistakenly exit on transient read errors on the
network socket (e.g. EINTR, EAGAIN); bz3297
* Create a dedicated contrib/gnome-ssk-askpass3.c source instead of
building it from the same file as used for GNOME2. Use the GNOME3
gdk_seat_grab() to manage keyboard/mouse/server grabs for better
compatibility with Wayland.
* Fix portability build errors bz3293 bz3292 bz3291 bz3278
* sshd(8): soft-disallow the fstatat64 syscall in the Linux
seccomp-bpf sandbox. bz3276
* unit tests: enable autoopt and misc unit tests that were
previously skipped
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available from the mirror sites:
https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/RELEASE_KEY.asc
Please note that the OpenPGP key used to sign releases has been
rotated for this release. The new key has been signed by the previous
key to provide continuity.
Reporting Bugs:
OpenSSH 8.5 was released on 2021-03-03. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
https://www.openssh.com/donations.html
Future deprecation notice
It is now possible[1] to perform chosen-prefix attacks against the
SHA-1 algorithm for less than USD$50K.
In the SSH protocol, the "ssh-rsa" signature scheme uses the SHA-1
hash algorithm in conjunction with the RSA public key algorithm.
OpenSSH will disable this signature scheme by default in the near
future.
Note that the deactivation of "ssh-rsa" signatures does not necessarily
require cessation of use for RSA keys. In the SSH protocol, keys may be
capable of signing using multiple algorithms. In particular, "ssh-rsa"
keys are capable of signing using "rsa-sha2-256" (RSA/SHA256),
"rsa-sha2-512" (RSA/SHA512) and "ssh-rsa" (RSA/SHA1). Only the last of
these is being turned off by default.
This algorithm is unfortunately still used widely despite the
existence of better alternatives, being the only remaining public key
signature algorithm specified by the original SSH RFCs that is still
enabled by default.
The better alternatives include:
* The RFC8332 RSA SHA-2 signature algorithms rsa-sha2-256/512. These
algorithms have the advantage of using the same key type as
"ssh-rsa" but use the safe SHA-2 hash algorithms. These have been
supported since OpenSSH 7.2 and are already used by default if the
client and server support them.
* The RFC8709 ssh-ed25519 signature algorithm. It has been supported
in OpenSSH since release 6.5.
* The RFC5656 ECDSA algorithms: ecdsa-sha2-nistp256/384/521. These
have been supported by OpenSSH since release 5.7.
To check whether a server is using the weak ssh-rsa public key
algorithm, for host authentication, try to connect to it after
removing the ssh-rsa algorithm from ssh(1)'s allowed list:
ssh -oHostKeyAlgorithms=-ssh-rsa user@host
If the host key verification fails and no other supported host key
types are available, the server software on that host should be
upgraded.
This release enables the UpdateHostKeys option by default to assist
the client by automatically migrating to better algorithms.
[1] "SHA-1 is a Shambles: First Chosen-Prefix Collision on SHA-1 and
Application to the PGP Web of Trust" Leurent, G and Peyrin, T
(2020) https://eprint.iacr.org/2020/014.pdf
Security
* ssh-agent(1): fixed a double-free memory corruption that was
introduced in OpenSSH 8.2 . We treat all such memory faults as
potentially exploitable. This bug could be reached by an attacker
with access to the agent socket.
On modern operating systems where the OS can provide information
about the user identity connected to a socket, OpenSSH ssh-agent
and sshd limit agent socket access only to the originating user
and root. Additional mitigation may be afforded by the system's
malloc(3)/free(3) implementation, if it detects double-free
conditions.
The most likely scenario for exploitation is a user forwarding an
agent either to an account shared with a malicious user or to a
host with an attacker holding root access.
* Portable sshd(8): Prevent excessively long username going to PAM.
This is a mitigation for a buffer overflow in Solaris' PAM username
handling (CVE-2020-14871), and is only enabled for Sun-derived PAM
implementations. This is not a problem in sshd itself, it only
prevents sshd from being used as a vector to attack Solaris' PAM.
It does not prevent the bug in PAM from being exploited via some
other PAM application. GHPR#212
Potentially-incompatible changes
This release includes a number of changes that may affect existing
configurations:
* ssh(1), sshd(8): this release changes the first-preference signature
algorithm from ECDSA to ED25519.
* ssh(1), sshd(8): set the TOS/DSCP specified in the configuration
for interactive use prior to TCP connect. The connection phase of
the SSH session is time-sensitive and often explicitly interactive.
The ultimate interactive/bulk TOS/DSCP will be set after
authentication completes.
* ssh(1), sshd(8): remove the pre-standardization cipher
rijndael-cbc@lysator.liu.se. It is an alias for aes256-cbc before
it was standardized in RFC4253 (2006), has been deprecated and
disabled by default since OpenSSH 7.2 (2016) and was only briefly
documented in ssh.1 in 2001.
* ssh(1), sshd(8): update/replace the experimental post-quantum
hybrid key exchange method based on Streamlined NTRU Prime coupled
with X25519.
The previous sntrup4591761x25519-sha512@tinyssh.org method is
replaced with sntrup761x25519-sha512@openssh.com. Per its
designers, the sntrup4591761 algorithm was superseded almost two
years ago by sntrup761.
(note this both the updated method and the one that it replaced are
disabled by default)
* ssh(1): disable CheckHostIP by default. It provides insignificant
benefits while making key rotation significantly more difficult,
especially for hosts behind IP-based load-balancers.
Changes since OpenSSH 8.4
New features
* ssh(1): this release enables UpdateHostkeys by default subject to
some conservative preconditions:
- The key was matched in the UserKnownHostsFile (and not in the
GlobalKnownHostsFile).
- The same key does not exist under another name.
- A certificate host key is not in use.
- known_hosts contains no matching wildcard hostname pattern.
- VerifyHostKeyDNS is not enabled.
- The default UserKnownHostsFile is in use.
We expect some of these conditions will be modified or relaxed in
future.
* ssh(1), sshd(8): add a new LogVerbose configuration directive for
that allows forcing maximum debug logging by file/function/line
pattern-lists.
* ssh(1): when prompting the user to accept a new hostkey, display
any other host names/addresses already associated with the key.
* ssh(1): allow UserKnownHostsFile=none to indicate that no
known_hosts file should be used to identify host keys.
* ssh(1): add a ssh_config KnownHostsCommand option that allows the
client to obtain known_hosts data from a command in addition to
the usual files.
* ssh(1): add a ssh_config PermitRemoteOpen option that allows the
client to restrict the destination when RemoteForward is used
with SOCKS.
* ssh(1): for FIDO keys, if a signature operation fails with a
"incorrect PIN" reason and no PIN was initially requested from the
user, then request a PIN and retry the operation. This supports
some biometric devices that fall back to requiring PIN when reading
of the biometric failed, and devices that require PINs for all
hosted credentials.
* sshd(8): implement client address-based rate-limiting via new
sshd_config(5) PerSourceMaxStartups and PerSourceNetBlockSize
directives that provide more fine-grained control on a per-origin
address basis than the global MaxStartups limit.
Bugfixes
* ssh(1): Prefix keyboard interactive prompts with "(user@host)" to
make it easier to determine which connection they are associated
with in cases like scp -3, ProxyJump, etc. bz#3224
* sshd(8): fix sshd_config SetEnv directives located inside Match
blocks. GHPR#201
* ssh(1): when requesting a FIDO token touch on stderr, inform the
user once the touch has been recorded.
* ssh(1): prevent integer overflow when ridiculously large
ConnectTimeout values are specified, capping the effective value
(for most platforms) at 24 days. bz#3229
* ssh(1): consider the ECDSA key subtype when ordering host key
algorithms in the client.
* ssh(1), sshd(8): rename the PubkeyAcceptedKeyTypes keyword to
PubkeyAcceptedAlgorithms. The previous name incorrectly suggested
that it control allowed key algorithms, when this option actually
specifies the signature algorithms that are accepted. The previous
name remains available as an alias. bz#3253
* ssh(1), sshd(8): similarly, rename HostbasedKeyTypes (ssh) and
HostbasedAcceptedKeyTypes (sshd) to HostbasedAcceptedAlgorithms.
* sftp-server(8): add missing lsetstat@openssh.com documentation
and advertisement in the server's SSH2_FXP_VERSION hello packet.
* ssh(1), sshd(8): more strictly enforce KEX state-machine by
banning packet types once they are received. Fixes memleak caused
by duplicate SSH2_MSG_KEX_DH_GEX_REQUEST (oss-fuzz #30078).
* sftp(1): allow the full range of UIDs/GIDs for chown/chgrp on 32bit
platforms instead of being limited by LONG_MAX. bz#3206
* Minor man page fixes (capitalization, commas, etc.) bz#3223
* sftp(1): when doing an sftp recursive upload or download of a
read-only directory, ensure that the directory is created with
write and execute permissions in the interim so that the transfer
can actually complete, then set the directory permission as the
final step. bz#3222
* ssh-keygen(1): document the -Z, check the validity of its argument
earlier and provide a better error message if it's not correct.
bz#2879
* ssh(1): ignore comments at the end of config lines in ssh_config,
similar to what we already do for sshd_config. bz#2320
* sshd_config(5): mention that DisableForwarding is valid in a
sshd_config Match block. bz3239
* sftp(1): fix incorrect sorting of "ls -ltr" under some
circumstances. bz3248.
* ssh(1), sshd(8): fix potential integer truncation of (unlikely)
timeout values. bz#3250
* ssh(1): make hostbased authentication send the signature algorithm
in its SSH2_MSG_USERAUTH_REQUEST packets instead of the key type.
This make HostbasedAcceptedAlgorithms do what it is supposed to -
filter on signature algorithm and not key type.
Portability
* sshd(8): add a number of platform-specific syscalls to the Linux
seccomp-bpf sandbox. bz#3232 bz#3260
* sshd(8): remove debug message from sigchld handler that could cause
deadlock on some platforms. bz#3259
* Sync contrib/ssh-copy-id with upstream.
* unittests: add a hostname function for systems that don't have it.
Some systems don't have a hostname command (it's not required by
POSIX). The do have uname -n (which is), but not all of those have
it report the FQDN.
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available from the mirror sites:
https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/RELEASE_KEY.asc
Please note that the OpenPGP key used to sign releases has been
rotated for this release. The new key has been signed by the previous
key to provide continuity.
Reporting Bugs:
OpenSSH 8.4 was released on 2020-09-27. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
https://www.openssh.com/donations.html
Future deprecation notice
It is now possible[1] to perform chosen-prefix attacks against the
SHA-1 algorithm for less than USD$50K. For this reason, we will be
disabling the "ssh-rsa" public key signature algorithm by default in a
near-future release.
This algorithm is unfortunately still used widely despite the
existence of better alternatives, being the only remaining public key
signature algorithm specified by the original SSH RFCs.
The better alternatives include:
* The RFC8332 RSA SHA-2 signature algorithms rsa-sha2-256/512. These
algorithms have the advantage of using the same key type as
"ssh-rsa" but use the safe SHA-2 hash algorithms. These have been
supported since OpenSSH 7.2 and are already used by default if the
client and server support them.
* The ssh-ed25519 signature algorithm. It has been supported in
OpenSSH since release 6.5.
* The RFC5656 ECDSA algorithms: ecdsa-sha2-nistp256/384/521. These
have been supported by OpenSSH since release 5.7.
To check whether a server is using the weak ssh-rsa public key
algorithm, for host authentication, try to connect to it after
removing the ssh-rsa algorithm from ssh(1)'s allowed list:
ssh -oHostKeyAlgorithms=-ssh-rsa user@host
If the host key verification fails and no other supported host key
types are available, the server software on that host should be
upgraded.
We intend to enable UpdateHostKeys by default in the next OpenSSH
release. This will assist the client by automatically migrating to
better algorithms. Users may consider enabling this option manually.
[1] "SHA-1 is a Shambles: First Chosen-Prefix Collision on SHA-1 and
Application to the PGP Web of Trust" Leurent, G and Peyrin, T
(2020) https://eprint.iacr.org/2020/014.pdf
Security
* ssh-agent(1): restrict ssh-agent from signing web challenges for
FIDO/U2F keys.
When signing messages in ssh-agent using a FIDO key that has an
application string that does not start with "ssh:", ensure that the
message being signed is one of the forms expected for the SSH protocol
(currently public key authentication and sshsig signatures).
This prevents ssh-agent forwarding on a host that has FIDO keys
attached granting the ability for the remote side to sign challenges
for web authentication using those keys too.
Note that the converse case of web browsers signing SSH challenges is
already precluded because no web RP can have the "ssh:" prefix in the
application string that we require.
* ssh-keygen(1): Enable FIDO 2.1 credProtect extension when generating
a FIDO resident key.
The recent FIDO 2.1 Client to Authenticator Protocol introduced a
"credProtect" feature to better protect resident keys. We use this
option to require a PIN prior to all operations that may retrieve
a resident key from a FIDO token.
Potentially-incompatible changes
This release includes a number of changes that may affect existing
configurations:
* For FIDO/U2F support, OpenSSH recommends the use of libfido2 1.5.0
or greater. Older libraries have limited support at the expense of
disabling particular features. These include resident keys, PIN-
required keys and multiple attached tokens.
* ssh-keygen(1): the format of the attestation information optionally
recorded when a FIDO key is generated has changed. It now includes
the authenticator data needed to validate attestation signatures.
* The API between OpenSSH and the FIDO token middleware has changed
and the SSH_SK_VERSION_MAJOR version has been incremented as a
result. Third-party middleware libraries must support the current
API version (7) to work with OpenSSH 8.4.
* The portable OpenSSH distribution now requires automake to rebuild
the configure script and supporting files. This is not required when
simply building portable OpenSSH from a release tar file.
Changes since OpenSSH 8.3
New features
* ssh(1), ssh-keygen(1): support for FIDO keys that require a PIN for
each use. These keys may be generated using ssh-keygen using a new
"verify-required" option. When a PIN-required key is used, the user
will be prompted for a PIN to complete the signature operation.
* sshd(8): authorized_keys now supports a new "verify-required"
option to require FIDO signatures assert that the token verified
that the user was present before making the signature. The FIDO
protocol supports multiple methods for user-verification, but
currently OpenSSH only supports PIN verification.
* sshd(8), ssh-keygen(1): add support for verifying FIDO webauthn
signatures. Webauthn is a standard for using FIDO keys in web
browsers. These signatures are a slightly different format to plain
FIDO signatures and thus require explicit support.
* ssh(1): allow some keywords to expand shell-style ${ENV}
environment variables. The supported keywords are CertificateFile,
ControlPath, IdentityAgent and IdentityFile, plus LocalForward and
RemoteForward when used for Unix domain socket paths. bz#3140
* ssh(1), ssh-agent(1): allow some additional control over the use of
ssh-askpass via a new $SSH_ASKPASS_REQUIRE environment variable,
including forcibly enabling and disabling its use. bz#69
* ssh(1): allow ssh_config(5)'s AddKeysToAgent keyword accept a time
limit for keys in addition to its current flag options. Time-
limited keys will automatically be removed from ssh-agent after
their expiry time has passed.
* scp(1), sftp(1): allow the -A flag to explicitly enable agent
forwarding in scp and sftp. The default remains to not forward an
agent, even when ssh_config enables it.
* ssh(1): add a '%k' TOKEN that expands to the effective HostKey of
the destination. This allows, e.g., keeping host keys in individual
files using "UserKnownHostsFile ~/.ssh/known_hosts.d/%k". bz#1654
* ssh(1): add %-TOKEN, environment variable and tilde expansion to
the UserKnownHostsFile directive, allowing the path to be
completed by the configuration (e.g. bz#1654)
* ssh-keygen(1): allow "ssh-add -d -" to read keys to be deleted
from stdin. bz#3180
* sshd(8): improve logging for MaxStartups connection throttling.
sshd will now log when it starts and stops throttling and periodically
while in this state. bz#3055
Bugfixes
* ssh(1), ssh-keygen(1): better support for multiple attached FIDO
tokens. In cases where OpenSSH cannot unambiguously determine which
token to direct a request to, the user is now required to select a
token by touching it. In cases of operations that require a PIN to
be verified, this avoids sending the wrong PIN to the wrong token
and incrementing the token's PIN failure counter (tokens
effectively erase their keys after too many PIN failures).
* sshd(8): fix Include before Match in sshd_config; bz#3122
* ssh(1): close stdin/out/error when forking after authentication
completes ("ssh -f ...") bz#3137
* ssh(1), sshd(8): limit the amount of channel input data buffered,
avoiding peers that advertise large windows but are slow to read
from causing high memory consumption.
* ssh-agent(1): handle multiple requests sent in a single write() to
the agent.
* sshd(8): allow sshd_config longer than 256k
* sshd(8): avoid spurious "Unable to load host key" message when sshd
load a private key but no public counterpart
* ssh(1): prefer the default hostkey algorithm list whenever we have
a hostkey that matches its best-preference algorithm.
* sshd(1): when ordering the hostkey algorithms to request from a
server, prefer certificate types if the known_hosts files contain a key
marked as a @cert-authority; bz#3157
* ssh(1): perform host key fingerprint comparisons for the "Are you
sure you want to continue connecting (yes/no/[fingerprint])?"
prompt with case sensitivity.
* sshd(8): ensure that address/masklen mismatches in sshd_config
yield fatal errors at daemon start time rather than later when
they are evaluated.
* ssh-keygen(1): ensure that certificate extensions are lexically
sorted. Previously if the user specified a custom extension then
the everything would be in order except the custom ones. bz#3198
* ssh(1): also compare username when checking for JumpHost loops.
bz#3057
* ssh-keygen(1): preserve group/world read permission on known_hosts
files across runs of "ssh-keygen -Rf /path". The old behaviour was
to remove all rights for group/other. bz#3146
* ssh-keygen(1): Mention the [-a rounds] flag in the ssh-keygen
manual page and usage().
* sshd(8): explicitly construct path to ~/.ssh/rc rather than
relying on it being relative to the current directory, so that it
can still be found if the shell startup changes its directory.
bz#3185
* sshd(8): when redirecting sshd's log output to a file, undo this
redirection after the session child process is forked(). Fixes
missing log messages when using this feature under some
circumstances.
* sshd(8): start ClientAliveInterval bookkeeping before first pass
through select() loop; fixed theoretical case where busy sshd may
ignore timeouts from client.
* ssh(1): only reset the ServerAliveInterval check when we receive
traffic from the server and ignore traffic from a port forwarding
client, preventing a client from keeping a connection alive when
it should be terminated. bz#2265
* ssh-keygen(1): avoid spurious error message when ssh-keygen
creates files outside ~/.ssh
* sftp-client(1): fix off-by-one error that caused sftp downloads to
make one more concurrent request that desired. This prevented using
sftp(1) in unpipelined request/response mode, which is useful when
debugging. bz#3054
* ssh(1), sshd(8): handle EINTR in waitfd() and timeout_connect()
helpers. bz#3071
* ssh(1), ssh-keygen(1): defer creation of ~/.ssh until we attempt to
write to it so we don't leave an empty .ssh directory when it's not
needed. bz#3156
* ssh(1), sshd(8): fix multiplier when parsing time specifications
when handling seconds after other units. bz#3171
Portability
* sshd(8): always send any PAM account messages. If the PAM account
stack returns any messages, always send them to the user and not
just if the check succeeds. bz#2049
* Implement some backwards compatibility for libfido2 libraries
older than 1.5.0. Note that use of an older library will result
in the loss of certain features including resident key support,
PIN support and support for multiple attached tokens.
* configure fixes for XCode 12
* gnome-ssh-askpass3: ensure the "close" button is not focused by
default for SSH_ASKPASS_PROMPT=none prompts. Avoids space/enter
accidentally dismissing FIDO touch notifications.
* gnome-ssh-askpass3: allow some control over textarea colour via
$GNOME_SSH_ASKPASS_FG_COLOR and $GNOME_SSH_ASKPASS_BG_COLOR
environment variables.
* sshd(8): document another PAM spec problem in a frustrated comment
* sshd(8): support NetBSD's utmpx.ut_ss address field. bz#960
* Add the ssh-sk-helper binary and its manpage to the RPM spec file
* Detect the Frankenstein monster of Linux/X32 and allow the sandbox
to function there. bz#3085
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available as RELEASE_KEY.asc from
the mirror sites.
Reporting Bugs:
OpenSSH 8.3 was released on 2020-05-27. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
https://www.openssh.com/donations.html
Future deprecation notice
It is now possible[1] to perform chosen-prefix attacks against the
SHA-1 algorithm for less than USD$50K. For this reason, we will be
disabling the "ssh-rsa" public key signature algorithm by default in a
near-future release.
This algorithm is unfortunately still used widely despite the
existence of better alternatives, being the only remaining public key
signature algorithm specified by the original SSH RFCs.
The better alternatives include:
* The RFC8332 RSA SHA-2 signature algorithms rsa-sha2-256/512. These
algorithms have the advantage of using the same key type as
"ssh-rsa" but use the safe SHA-2 hash algorithms. These have been
supported since OpenSSH 7.2 and are already used by default if the
client and server support them.
* The ssh-ed25519 signature algorithm. It has been supported in
OpenSSH since release 6.5.
* The RFC5656 ECDSA algorithms: ecdsa-sha2-nistp256/384/521. These
have been supported by OpenSSH since release 5.7.
To check whether a server is using the weak ssh-rsa public key
algorithm, for host authentication, try to connect to it after
removing the ssh-rsa algorithm from ssh(1)'s allowed list:
ssh -oHostKeyAlgorithms=-ssh-rsa user@host
If the host key verification fails and no other supported host key
types are available, the server software on that host should be
upgraded.
A future release of OpenSSH will enable UpdateHostKeys by default
to allow the client to automatically migrate to better algorithms.
Users may consider enabling this option manually. Vendors of devices
that implement the SSH protocol should ensure that they support the
new signature algorithms for RSA keys.
[1] "SHA-1 is a Shambles: First Chosen-Prefix Collision on SHA-1 and
Application to the PGP Web of Trust" Leurent, G and Peyrin, T
(2020) https://eprint.iacr.org/2020/014.pdf
Security
* scp(1): when receiving files, scp(1) could be become desynchronised
if a utimes(2) system call failed. This could allow file contents
to be interpreted as file metadata and thereby permit an adversary
to craft a file system that, when copied with scp(1) in a
configuration that caused utimes(2) to fail (e.g. under a SELinux
policy or syscall sandbox), transferred different file names and
contents to the actual file system layout.
Exploitation of this is not likely as utimes(2) does not fail under
normal circumstances. Successful exploitation is not silent - the
output of scp(1) would show transfer errors followed by the actual
file(s) that were received.
Finally, filenames returned from the peer are (since openssh-8.0)
matched against the user's requested destination, thereby
disallowing a successful exploit from writing files outside the
user's selected target glob (or directory, in the case of a
recursive transfer). This ensures that this attack can achieve no
more than a hostile peer is already able to achieve within the scp
protocol.
Potentially-incompatible changes
This release includes a number of changes that may affect existing
configurations:
* sftp(1): reject an argument of "-1" in the same way as ssh(1) and
scp(1) do instead of accepting and silently ignoring it.
Changes since OpenSSH 8.2
The focus of this release is bug fixing.
New Features
* sshd(8): make IgnoreRhosts a tri-state option: "yes" to ignore
rhosts/shosts, "no" allow rhosts/shosts or (new) "shosts-only"
to allow .shosts files but not .rhosts.
* sshd(8): allow the IgnoreRhosts directive to appear anywhere in a
sshd_config, not just before any Match blocks; bz3148
* ssh(1): add %TOKEN percent expansion for the LocalFoward and
RemoteForward keywords when used for Unix domain socket forwarding.
bz#3014
* all: allow loading public keys from the unencrypted envelope of a
private key file if no corresponding public key file is present.
* ssh(1), sshd(8): prefer to use chacha20 from libcrypto where
possible instead of the (slower) portable C implementation included
in OpenSSH.
* ssh-keygen(1): add ability to dump the contents of a binary key
revocation list via "ssh-keygen -lQf /path" bz#3132
Bugfixes
* ssh(1): fix IdentitiesOnly=yes to also apply to keys loaded from
a PKCS11Provider; bz#3141
* ssh-keygen(1): avoid NULL dereference when trying to convert an
invalid RFC4716 private key.
* scp(1): when performing remote-to-remote copies using "scp -3",
start the second ssh(1) channel with BatchMode=yes enabled to
avoid confusing and non-deterministic ordering of prompts.
* ssh(1), ssh-keygen(1): when signing a challenge using a FIDO token,
perform hashing of the message to be signed in the middleware layer
rather than in OpenSSH code. This permits the use of security key
middlewares that perform the hashing implicitly, such as Windows
Hello.
* ssh(1): fix incorrect error message for "too many known hosts
files." bz#3149
* ssh(1): make failures when establishing "Tunnel" forwarding
terminate the connection when ExitOnForwardFailure is enabled;
bz#3116
* ssh-keygen(1): fix printing of fingerprints on private keys and add
a regression test for same.
* sshd(8): document order of checking AuthorizedKeysFile (first) and
AuthorizedKeysCommand (subsequently, if the file doesn't match);
bz#3134
* sshd(8): document that /etc/hosts.equiv and /etc/shosts.equiv are
not considered for HostbasedAuthentication when the target user is
root; bz#3148
* ssh(1), ssh-keygen(1): fix NULL dereference in private certificate
key parsing (oss-fuzz #20074).
* ssh(1), sshd(8): more consistency between sets of %TOKENS are
accepted in various configuration options.
* ssh(1), ssh-keygen(1): improve error messages for some common
PKCS#11 C_Login failure cases; bz#3130
* ssh(1), sshd(8): make error messages for problems during SSH banner
exchange consistent with other SSH transport-layer error messages
and ensure they include the relevant IP addresses bz#3129
* various: fix a number of spelling errors in comments and debug/error
messages
* ssh-keygen(1), ssh-add(1): when downloading FIDO2 resident keys
from a token, don't prompt for a PIN until the token has told us
that it needs one. Avoids double-prompting on devices that
implement on-device authentication.
* sshd(8), ssh-keygen(1): no-touch-required FIDO certificate option
should be an extension, not a critical option.
* ssh(1), ssh-keygen(1), ssh-add(1): offer a better error message
when trying to use a FIDO key function and SecurityKeyProvider is
empty.
* ssh-add(1), ssh-agent(8): ensure that a key lifetime fits within
the values allowed by the wire format (u32). Prevents integer
wraparound of the timeout values. bz#3119
* ssh(1): detect and prevent trivial configuration loops when using
ProxyJump. bz#3057.
Portability
* Detect systems where signals flagged with SA_RESTART will interrupt
select(2). POSIX permits implementations to choose whether
select(2) will return when interrupted with a SA_RESTART-flagged
signal, but OpenSSH requires interrupting behaviour.
* Several compilation fixes for HP/UX and AIX.
* On platforms that do not support setting process-wide routing
domains (all excepting OpenBSD at present), fail to accept a
configuration attempts to set one at process start time rather than
fatally erroring at run time. bz#3126
* Improve detection of egrep (used in regression tests) on platforms
that offer a poor default one (e.g. Solaris).
* A number of shell portability fixes for the regression tests.
* Fix theoretical infinite loop in the glob(3) replacement
implementation.
* Fix seccomp sandbox compilation problems for some Linux
configurations bz#3085
* Improved detection of libfido2 and some compilation fixes for some
configurations when --with-security-key-builtin is selected.
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available as RELEASE_KEY.asc from
the mirror sites.
Reporting Bugs:
OpenSSH 8.2 was released on 2020-02-14. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
https://www.openssh.com/donations.html
Future deprecation notice
It is now possible[1] to perform chosen-prefix attacks against the
SHA-1 hash algorithm for less than USD$50K. For this reason, we will
be disabling the "ssh-rsa" public key signature algorithm that depends
on SHA-1 by default in a near-future release.
This algorithm is unfortunately still used widely despite the
existence of better alternatives, being the only remaining public key
signature algorithm specified by the original SSH RFCs.
The better alternatives include:
* The RFC8332 RSA SHA-2 signature algorithms rsa-sha2-256/512. These
algorithms have the advantage of using the same key type as
"ssh-rsa" but use the safe SHA-2 hash algorithms. These have been
supported since OpenSSH 7.2 and are already used by default if the
client and server support them.
* The ssh-ed25519 signature algorithm. It has been supported in
OpenSSH since release 6.5.
* The RFC5656 ECDSA algorithms: ecdsa-sha2-nistp256/384/521. These
have been supported by OpenSSH since release 5.7.
To check whether a server is using the weak ssh-rsa public key
algorithm for host authentication, try to connect to it after
removing the ssh-rsa algorithm from ssh(1)'s allowed list:
ssh -oHostKeyAlgorithms=-ssh-rsa user@host
If the host key verification fails and no other supported host key
types are available, the server software on that host should be
upgraded.
A future release of OpenSSH will enable UpdateHostKeys by default
to allow the client to automatically migrate to better algorithms.
Users may consider enabling this option manually.
[1] "SHA-1 is a Shambles: First Chosen-Prefix Collision on SHA-1 and
Application to the PGP Web of Trust" Leurent, G and Peyrin, T
(2020) https://eprint.iacr.org/2020/014.pdf
Security
* ssh(1), sshd(8), ssh-keygen(1): this release removes the "ssh-rsa"
(RSA/SHA1) algorithm from those accepted for certificate signatures
(i.e. the client and server CASignatureAlgorithms option) and will
use the rsa-sha2-512 signature algorithm by default when the
ssh-keygen(1) CA signs new certificates.
Certificates are at special risk to the aforementioned SHA1
collision vulnerability as an attacker has effectively unlimited
time in which to craft a collision that yields them a valid
certificate, far more than the relatively brief LoginGraceTime
window that they have to forge a host key signature.
The OpenSSH certificate format includes a CA-specified (typically
random) nonce value near the start of the certificate that should
make exploitation of chosen-prefix collisions in this context
challenging, as the attacker does not have full control over the
prefix that actually gets signed. Nonetheless, SHA1 is now a
demonstrably broken algorithm and further improvements in attacks
are highly likely.
OpenSSH releases prior to 7.2 do not support the newer RSA/SHA2
algorithms and will refuse to accept certificates signed by an
OpenSSH 8.2+ CA using RSA keys unless the unsafe algorithm is
explicitly selected during signing ("ssh-keygen -t ssh-rsa").
Older clients/servers may use another CA key type such as
ssh-ed25519 (supported since OpenSSH 6.5) or one of the
ecdsa-sha2-nistp256/384/521 types (supported since OpenSSH 5.7)
instead if they cannot be upgraded.
Potentially-incompatible changes
This release includes a number of changes that may affect existing
configurations:
* ssh(1), sshd(8): the above removal of "ssh-rsa" from the accepted
CASignatureAlgorithms list.
* ssh(1), sshd(8): this release removes diffie-hellman-group14-sha1
from the default key exchange proposal for both the client and
server.
* ssh-keygen(1): the command-line options related to the generation
and screening of safe prime numbers used by the
diffie-hellman-group-exchange-* key exchange algorithms have
changed. Most options have been folded under the -O flag.
* sshd(8): the sshd listener process title visible to ps(1) has
changed to include information about the number of connections that
are currently attempting authentication and the limits configured
by MaxStartups.
* ssh-sk-helper(8): this is a new binary. It is used by the FIDO/U2F
support to provide address-space isolation for token middleware
libraries (including the internal one). It needs to be installed
in the expected path, typically under /usr/libexec or similar.
Changes since OpenSSH 8.1
This release contains some significant new features.
FIDO/U2F Support
This release adds support for FIDO/U2F hardware authenticators to
OpenSSH. U2F/FIDO are open standards for inexpensive two-factor
authentication hardware that are widely used for website
authentication. In OpenSSH FIDO devices are supported by new public
key types "ecdsa-sk" and "ed25519-sk", along with corresponding
certificate types.
ssh-keygen(1) may be used to generate a FIDO token-backed key, after
which they may be used much like any other key type supported by
OpenSSH, so long as the hardware token is attached when the keys are
used. FIDO tokens also generally require the user explicitly authorise
operations by touching or tapping them.
Generating a FIDO key requires the token be attached, and will usually
require the user tap the token to confirm the operation:
$ ssh-keygen -t ecdsa-sk -f ~/.ssh/id_ecdsa_sk
Generating public/private ecdsa-sk key pair.
You may need to touch your security key to authorize key generation.
Enter file in which to save the key (/home/djm/.ssh/id_ecdsa_sk):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/djm/.ssh/id_ecdsa_sk
Your public key has been saved in /home/djm/.ssh/id_ecdsa_sk.pub
This will yield a public and private key-pair. The private key file
should be useless to an attacker who does not have access to the
physical token. After generation, this key may be used like any other
supported key in OpenSSH and may be listed in authorized_keys, added
to ssh-agent(1), etc. The only additional stipulation is that the FIDO
token that the key belongs to must be attached when the key is used.
FIDO tokens are most commonly connected via USB but may be attached
via other means such as Bluetooth or NFC. In OpenSSH, communication
with the token is managed via a middleware library, specified by the
SecurityKeyProvider directive in ssh/sshd_config(5) or the
$SSH_SK_PROVIDER environment variable for ssh-keygen(1) and
ssh-add(1). The API for this middleware is documented in the sk-api.h
and PROTOCOL.u2f files in the source distribution.
OpenSSH includes a middleware ("SecurityKeyProvider=internal") with
support for USB tokens. It is automatically enabled in OpenBSD and may
be enabled in portable OpenSSH via the configure flag
--with-security-key-builtin. If the internal middleware is enabled
then it is automatically used by default. This internal middleware
requires that libfido2 (https://github.com/Yubico/libfido2)and its
dependencies be installed. We recommend that packagers of portable
OpenSSH enable the built-in middleware, as it provides the
lowest-friction experience for users.
Note: FIDO/U2F tokens are required to implement the ECDSA-P256
"ecdsa-sk" key type, but hardware support for Ed25519 "ed25519-sk" is
less common. Similarly, not all hardware tokens support some of the
optional features such as resident keys.
The protocol-level changes to support FIDO/U2F keys in SSH are
documented in the PROTOCOL.u2f file in the OpenSSH source
distribution.
There are a number of supporting changes to this feature:
* ssh-keygen(1): add a "no-touch-required" option when generating
FIDO-hosted keys, that disables their default behaviour of
requiring a physical touch/tap on the token during authentication.
Note: not all tokens support disabling the touch requirement.
* sshd(8): add a sshd_config PubkeyAuthOptions directive that
collects miscellaneous public key authentication-related options
for sshd(8). At present it supports only a single option
"no-touch-required". This causes sshd to skip its default check for
FIDO/U2F keys that the signature was authorised by a touch or press
event on the token hardware.
* ssh(1), sshd(8), ssh-keygen(1): add a "no-touch-required" option
for authorized_keys and a similar extension for certificates. This
option disables the default requirement that FIDO key signatures
attest that the user touched their key to authorize them, mirroring
the similar PubkeyAuthOptions sshd_config option.
* ssh-keygen(1): add support for the writing the FIDO attestation
information that is returned when new keys are generated via the
"-O write-attestation=/path" option. FIDO attestation certificates
may be used to verify that a FIDO key is hosted in trusted
hardware. OpenSSH does not currently make use of this information,
beyond optionally writing it to disk.
FIDO2 resident keys
FIDO/U2F OpenSSH keys consist of two parts: a "key handle" part stored
in the private key file on disk, and a per-device private key that is
unique to each FIDO/U2F token and that cannot be exported from the
token hardware. These are combined by the hardware at authentication
time to derive the real key that is used to sign authentication
challenges.
For tokens that are required to move between computers, it can be
cumbersome to have to move the private key file first. To avoid this
requirement, tokens implementing the newer FIDO2 standard support
"resident keys", where it is possible to effectively retrieve the key
handle part of the key from the hardware.
OpenSSH supports this feature, allowing resident keys to be generated
using the ssh-keygen(1) "-O resident" flag. This will produce a
public/private key pair as usual, but it will be possible to retrieve
the private key part from the token later. This may be done using
"ssh-keygen -K", which will download all available resident keys from
the tokens attached to the host and write public/private key files
for them. It is also possible to download and add resident keys
directly to ssh-agent(1) without writing files to the file-system
using "ssh-add -K".
Resident keys are indexed on the token by the application string and
user ID. By default, OpenSSH uses an application string of "ssh:" and
an empty user ID. If multiple resident keys on a single token are
desired then it may be necessary to override one or both of these
defaults using the ssh-keygen(1) "-O application=" or "-O user="
options. Note: OpenSSH will only download and use resident keys whose
application string begins with "ssh:"
Storing both parts of a key on a FIDO token increases the likelihood
of an attacker being able to use a stolen token device. For this
reason, tokens should enforce PIN authentication before allowing
download of keys, and users should set a PIN on their tokens before
creating any resident keys.
Other New Features
* sshd(8): add an Include sshd_config keyword that allows including
additional configuration files via glob(3) patterns. bz2468
* ssh(1)/sshd(8): make the LE (low effort) DSCP code point available
via the IPQoS directive; bz2986,
* ssh(1): when AddKeysToAgent=yes is set and the key contains no
comment, add the key to the agent with the key's path as the
comment. bz2564
* ssh-keygen(1), ssh-agent(1): expose PKCS#11 key labels and X.509
subjects as key comments, rather than simply listing the PKCS#11
provider library path. PR138
* ssh-keygen(1): allow PEM export of DSA and ECDSA keys; bz3091
* ssh(1), sshd(8): make zlib compile-time optional, available via the
Makefile.inc ZLIB flag on OpenBSD or via the --with-zlib configure
option for OpenSSH portable.
* sshd(8): when clients get denied by MaxStartups, send a
notification prior to the SSH2 protocol banner according to
RFC4253 section 4.2.
* ssh(1), ssh-agent(1): when invoking the $SSH_ASKPASS prompt
program, pass a hint to the program to describe the type of
desired prompt. The possible values are "confirm" (indicating
that a yes/no confirmation dialog with no text entry should be
shown), "none" (to indicate an informational message only), or
blank for the original ssh-askpass behaviour of requesting a
password/phrase.
* ssh(1): allow forwarding a different agent socket to the path
specified by $SSH_AUTH_SOCK, by extending the existing ForwardAgent
option to accepting an explicit path or the name of an environment
variable in addition to yes/no.
* ssh-keygen(1): add a new signature operations "find-principals" to
look up the principal associated with a signature from an allowed-
signers file.
* sshd(8): expose the number of currently-authenticating connections
along with the MaxStartups limit in the process title visible to
"ps".
Bugfixes
* sshd(8): make ClientAliveCountMax=0 have sensible semantics: it
will now disable connection killing entirely rather than the
current behaviour of instantly killing the connection after the
first liveness test regardless of success. bz2627
* sshd(8): clarify order of AllowUsers / DenyUsers vs AllowGroups /
DenyGroups in the sshd(8) manual page. bz1690
* sshd(8): better describe HashKnownHosts in the manual page. bz2560
* sshd(8): clarify that permitopen=/PermitOpen do no name or
address translation in the manual page. bz3099
* sshd(8): allow the UpdateHostKeys feature to function when
multiple known_hosts files are in use. When updating host keys,
ssh will now search subsequent known_hosts files, but will add
updated host keys to the first specified file only. bz2738
* All: replace all calls to signal(2) with a wrapper around
sigaction(2). This wrapper blocks all other signals during the
handler preventing races between handlers, and sets SA_RESTART
which should reduce the potential for short read/write operations.
* sftp(1): fix a race condition in the SIGCHILD handler that could
turn in to a kill(-1); bz3084
* sshd(8): fix a case where valid (but extremely large) SSH channel
IDs were being incorrectly rejected. bz3098
* ssh(1): when checking host key fingerprints as answers to new
hostkey prompts, ignore whitespace surrounding the fingerprint
itself.
* All: wait for file descriptors to be readable or writeable during
non-blocking connect, not just readable. Prevents a timeout when
the server doesn't immediately send a banner (e.g. multiplexers
like sslh)
* sshd_config(5): document the sntrup4591761x25519-sha512@tinyssh.org
key exchange algorithm. PR#151
Portability
* sshd(8): multiple adjustments to the Linux seccomp sandbox:
- Non-fatally deny IPC syscalls in sandbox
- Allow clock_gettime64() in sandbox (MIPS / glibc >= 2.31)
- Allow clock_nanosleep_time64 in sandbox (ARM) bz3100
- Allow clock_nanosleep() in sandbox (recent glibc) bz3093
* Explicit check for memmem declaration and fix up declaration if the
system headers lack it. bz3102
Checksums:
Note: the openssh-8.2 tarball for OpenBSD that was initially released
advertised an incorrect version for "ssh -V" and the sshd server
banner. The above tarball replace the incorrect release, which has
been renamed to openssh-8.2.tar.gz.incorrect. These are the checksums
for the original, incorrect tarball:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available as RELEASE_KEY.asc from
the mirror sites.
Reporting Bugs:
OpenSSH 8.1 was released on 2019-10-09. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
http://www.openssh.com/donations.html
Security
* ssh(1), sshd(8), ssh-add(1), ssh-keygen(1): an exploitable integer
overflow bug was found in the private key parsing code for the XMSS
key type. This key type is still experimental and support for it is
not compiled by default. No user-facing autoconf option exists in
portable OpenSSH to enable it. This bug was found by Adam Zabrocki
and reported via SecuriTeam's SSD program.
* ssh(1), sshd(8), ssh-agent(1): add protection for private keys at
rest in RAM against speculation and memory side-channel attacks like
Spectre, Meltdown and Rambleed. This release encrypts private keys
when they are not in use with a symmetric key that is derived from a
relatively large "prekey" consisting of random data (currently 16KB).
Potentially-incompatible changes
This release includes a number of changes that may affect existing
configurations:
* ssh-keygen(1): when acting as a CA and signing certificates with
an RSA key, default to using the rsa-sha2-512 signature algorithm.
Certificates signed by RSA keys will therefore be incompatible
with OpenSSH versions prior to 7.2 unless the default is
overridden (using "ssh-keygen -t ssh-rsa -s ...").
Changes since OpenSSH 8.0
This release is focused on bug-fixing.
New Features
* ssh(1): Allow %n to be expanded in ProxyCommand strings
* ssh(1), sshd(8): Allow prepending a list of algorithms to the
default set by starting the list with the '^' character, E.g.
"HostKeyAlgorithms ^ssh-ed25519"
* ssh-keygen(1): add an experimental lightweight signature and
verification ability. Signatures may be made using regular ssh keys
held on disk or stored in a ssh-agent and verified against an
authorized_keys-like list of allowed keys. Signatures embed a
namespace that prevents confusion and attacks between different
usage domains (e.g. files vs email).
* ssh-keygen(1): print key comment when extracting public key from a
private key. bz#3052
* ssh-keygen(1): accept the verbose flag when searching for host keys
in known hosts (i.e. "ssh-keygen -vF host") to print the matching
host's random-art signature too. bz#3003
* All: support PKCS8 as an optional format for storage of private
keys to disk. The OpenSSH native key format remains the default,
but PKCS8 is a superior format to PEM if interoperability with
non-OpenSSH software is required, as it may use a less insecure
key derivation function than PEM's.
Bugfixes
* ssh(1): if a PKCS#11 token returns no keys then try to login and
refetch them. Based on patch from Jakub Jelen; bz#2430
* ssh(1): produce a useful error message if the user's shell is set
incorrectly during "match exec" processing. bz#2791
* sftp(1): allow the maximum uint32 value for the argument passed
to -b which allows better error messages from later validation.
bz#3050
* ssh(1): avoid pledge sandbox violations in some combinations of
remote forwarding, connection multiplexing and ControlMaster.
* ssh-keyscan(1): include SHA2-variant RSA key algorithms in KEX
proposal; allows ssh-keyscan to harvest keys from servers that
disable old SHA1 ssh-rsa. bz#3029
* sftp(1): print explicit "not modified" message if a file was
requested for resumed download but was considered already complete.
bz#2978
* sftp(1): fix a typo and make move right to the
closest end of a word just like moves left to the
closest beginning of a word.
* sshd(8): cap the number of permitopen/permitlisten directives
allowed to appear on a single authorized_keys line.
* All: fix a number of memory leaks (one-off or on exit paths).
* Regression tests: a number of fixes and improvements, including
fixes to the interop tests, adding the ability to run most tests
on builds that disable OpenSSL support, better support for running
tests under Valgrind and a number of bug-fixes.
* ssh(1), sshd(8): check for convtime() refusing to accept times that
resolve to LONG_MAX Reported by Kirk Wolf bz2977
* ssh(1): slightly more instructive error message when the user
specifies multiple -J options on the command-line. bz3015
* ssh-agent(1): process agent requests for RSA certificate private
keys using correct signature algorithm when requested. bz3016
* sftp(1): check for user@host when parsing sftp target. This
allows user@[1.2.3.4] to work without a path. bz#2999
* sshd(8): enlarge format buffer size for certificate serial
number so the log message can record any 64-bit integer without
truncation. bz#3012
* sshd(8): for PermitOpen violations add the remote host and port to
be able to more easily ascertain the source of the request. Add the
same logging for PermitListen violations which where not previously
logged at all.
* scp(1), sftp(1): use the correct POSIX format style for left
justification for the transfer progress meter. bz#3002
* sshd(8) when examining a configuration using sshd -T, assume any
attribute not provided by -C does not match, which allows it to work
when sshd_config contains a Match directive with or without -C.
bz#2858
* ssh(1), ssh-keygen(1): downgrade PKCS#11 "provider returned no
slots" warning from log level error to debug. This is common when
attempting to enumerate keys on smartcard readers with no cards
plugged in. bz#3058
* ssh(1), ssh-keygen(1): do not unconditionally log in to PKCS#11
tokens. Avoids spurious PIN prompts for keys not selected for
authentication in ssh(1) and when listing public keys available in
a token using ssh-keygen(1). bz#3006
Portability
* ssh(1): fix SIGWINCH delivery of Solaris for multiplexed sessions
bz#3030
* ssh(1), sshd(8): fix typo that prevented detection of Linux VRF
* sshd(8): add no-op implementation of pam_putenv to avoid build
breakage on platforms where the PAM implementation lacks this
function (e.g. HP-UX). bz#3008
* sftp-server(8): fix Solaris privilege sandbox from preventing
the legacy sftp rename operation from working (was refusing to
allow hard links to files owned by other users). bz#3036
* All: add a proc_pidinfo()-based closefrom() for OS X to avoid
the need to brute-force close all high-numbered file descriptors.
bz#3049
* sshd(8): in the Linux seccomp-bpf sandbox, allow mprotect(2) with
PROT_(READ|WRITE|NONE) only. This syscall is used by some hardened
heap allocators. Github PR#142
* sshd(8): in the Linux seccomp-bpf sandbox, allow the s390-specific
ioctl for ECC hardware support.
* All: use "doc" man page format if the mandoc(1) tool is present on
the system. Previously configure would not select the "doc" man
page format if mandoc was present but nroff was not.
* sshd(8): don't install duplicate STREAMS modules on Solaris; check
if STREAMS modules are already installed on a pty before installing
since when compiling with XPG>=4 they will likely be installed
already. Prevents hangs and duplicate lines on the terminal.
bz#2945 and bz#2998,
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available as RELEASE_KEY.asc from
the mirror sites.
Reporting Bugs:
OpenSSH 8.0 was released on 2019-04-17. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
http://www.openssh.com/donations.html
Security
This release contains mitigation for a weakness in the scp(1) tool
and protocol (CVE-2019-6111): when copying files from a remote system
to a local directory, scp(1) did not verify that the filenames that
the server sent matched those requested by the client. This could
allow a hostile server to create or clobber unexpected local files
with attacker-controlled content.
This release adds client-side checking that the filenames sent from
the server match the command-line request,
The scp protocol is outdated, inflexible and not readily fixed. We
recommend the use of more modern protocols like sftp and rsync for
file transfer instead.
Potentially-incompatible changes
This release includes a number of changes that may affect existing
configurations:
* scp(1): Relating to the above changes to scp(1); the scp protocol
relies on the remote shell for wildcard expansion, so there is no
infallible way for the client's wildcard matching to perfectly
reflect the server's. If there is a difference between client and
server wildcard expansion, the client may refuse files from the
server. For this reason, we have provided a new "-T" flag to scp
that disables these client-side checks at the risk of
reintroducing the attack described above.
* sshd(8): Remove support for obsolete "host/port" syntax. Slash-
separated host/port was added in 2001 as an alternative to
host:port syntax for the benefit of IPv6 users. These days there
are established standards for this like [::1]:22 and the slash
syntax is easily mistaken for CIDR notation, which OpenSSH
supports for some things. Remove the slash notation from
ListenAddress and PermitOpen; bz#2335
Changes since OpenSSH 7.9
This release is focused on new features and internal refactoring.
New Features
* ssh(1), ssh-agent(1), ssh-add(1): Add support for ECDSA keys in
PKCS#11 tokens.
* ssh(1), sshd(8): Add experimental quantum-computing resistant
key exchange method, based on a combination of Streamlined NTRU
Prime 4591^761 and X25519.
* ssh-keygen(1): Increase the default RSA key size to 3072 bits,
following NIST Special Publication 800-57's guidance for a
128-bit equivalent symmetric security level.
* ssh(1): Allow "PKCS11Provider=none" to override later instances of
the PKCS11Provider directive in ssh_config; bz#2974
* sshd(8): Add a log message for situations where a connection is
dropped for attempting to run a command but a sshd_config
ForceCommand=internal-sftp restriction is in effect; bz#2960
* ssh(1): When prompting whether to record a new host key, accept
the key fingerprint as a synonym for "yes". This allows the user
to paste a fingerprint obtained out of band at the prompt and
have the client do the comparison for you.
* ssh-keygen(1): When signing multiple certificates on a single
command-line invocation, allow automatically incrementing the
certificate serial number.
* scp(1), sftp(1): Accept -J option as an alias to ProxyJump on
the scp and sftp command-lines.
* ssh-agent(1), ssh-pkcs11-helper(8), ssh-add(1): Accept "-v"
command-line flags to increase the verbosity of output; pass
verbose flags though to subprocesses, such as ssh-pkcs11-helper
started from ssh-agent.
* ssh-add(1): Add a "-T" option to allowing testing whether keys in
an agent are usable by performing a signature and a verification.
* sftp-server(8): Add a "lsetstat@openssh.com" protocol extension
that replicates the functionality of the existing SSH2_FXP_SETSTAT
operation but does not follow symlinks. bz#2067
* sftp(1): Add "-h" flag to chown/chgrp/chmod commands to request
they do not follow symlinks.
* sshd(8): Expose $SSH_CONNECTION in the PAM environment. This makes
the connection 4-tuple available to PAM modules that wish to use
it in decision-making. bz#2741
* sshd(8): Add a ssh_config "Match final" predicate Matches in same
pass as "Match canonical" but doesn't require hostname
canonicalisation be enabled. bz#2906
* sftp(1): Support a prefix of '@' to suppress echo of sftp batch
commands; bz#2926
* ssh-keygen(1): When printing certificate contents using
"ssh-keygen -Lf /path/certificate", include the algorithm that
the CA used to sign the cert.
Bugfixes
* sshd(8): Fix authentication failures when sshd_config contains
"AuthenticationMethods any" inside a Match block that overrides
a more restrictive default.
* sshd(8): Avoid sending duplicate keepalives when ClientAliveCount
is enabled.
* sshd(8): Fix two race conditions related to SIGHUP daemon restart.
Remnant file descriptors in recently-forked child processes could
block the parent sshd's attempt to listen(2) to the configured
addresses. Also, the restarting parent sshd could exit before any
child processes that were awaiting their re-execution state had
completed reading it, leaving them in a fallback path.
* ssh(1): Fix stdout potentially being redirected to /dev/null when
ProxyCommand=- was in use.
* sshd(8): Avoid sending SIGPIPE to child processes if they attempt
to write to stderr after their parent processes have exited;
bz#2071
* ssh(1): Fix bad interaction between the ssh_config ConnectTimeout
and ConnectionAttempts directives - connection attempts after the
first were ignoring the requested timeout; bz#2918
* ssh-keyscan(1): Return a non-zero exit status if no keys were
found; bz#2903
* scp(1): Sanitize scp filenames to allow UTF-8 characters without
terminal control sequences; bz#2434
* sshd(8): Fix confusion between ClientAliveInterval and time-based
RekeyLimit that could cause connections to be incorrectly closed.
bz#2757
* ssh(1), ssh-add(1): Correct some bugs in PKCS#11 token PIN
handling at initial token login. The attempt to read the PIN
could be skipped in some cases, particularly on devices with
integrated PIN readers. This would lead to an inability to
retrieve keys from these tokens. bz#2652
* ssh(1), ssh-add(1): Support keys on PKCS#11 tokens that set the
CKA_ALWAYS_AUTHENTICATE flag by requiring a fresh login after the
C_SignInit operation. bz#2638
* ssh(1): Improve documentation for ProxyJump/-J, clarifying that
local configuration does not apply to jump hosts.
* ssh-keygen(1): Clarify manual - ssh-keygen -e only writes
public keys, not private.
* ssh(1), sshd(8): be more strict in processing protocol banners,
allowing \r characters only immediately before \n.
* Various: fix a number of memory leaks, including bz#2942 and
bz#2938
* scp(1), sftp(1): fix calculation of initial bandwidth limits.
Account for bytes written before the timer starts and adjust the
schedule on which recalculations are performed. Avoids an initial
burst of traffic and yields more accurate bandwidth limits;
bz#2927
* sshd(8): Only consider the ext-info-c extension during the initial
key eschange. It shouldn't be sent in subsequent ones, but if it
is present we should ignore it. This prevents sshd from sending a
SSH_MSG_EXT_INFO for REKEX for buggy these clients. bz#2929
* ssh-keygen(1): Clarify manual that ssh-keygen -F (find host in
authorized_keys) and -R (remove host from authorized_keys) options
may accept either a bare hostname or a [hostname]:port combo.
bz#2935
* ssh(1): Don't attempt to connect to empty SSH_AUTH_SOCK; bz#2936
* sshd(8): Silence error messages when sshd fails to load some of
the default host keys. Failure to load an explicitly-configured
hostkey is still an error, and failure to load any host key is
still fatal. pr/103
* ssh(1): Redirect stderr of ProxyCommands to /dev/null when ssh is
started with ControlPersist; prevents random ProxyCommand output
from interfering with session output.
* ssh(1): The ssh client was keeping a redundant ssh-agent socket
(leftover from authentication) around for the life of the
connection; bz#2912
* sshd(8): Fix bug in HostbasedAcceptedKeyTypes and
PubkeyAcceptedKeyTypes options. If only RSA-SHA2 signature types
were specified, then authentication would always fail for RSA keys
as the monitor checks only the base key (not the signature
algorithm) type against *AcceptedKeyTypes. bz#2746
* ssh(1): Request correct signature types from ssh-agent when
certificate keys and RSA-SHA2 signatures are in use.
Portability
* sshd(8): On Cygwin, run as SYSTEM where possible, using S4U for
token creation if it supports MsV1_0 S4U Logon.
* sshd(8): On Cygwin, use custom user/group matching code that
respects the OS' behaviour of case-insensitive matching.
* sshd(8): Don't set $MAIL if UsePAM=yes as PAM typically specifies
the user environment if it's enabled; bz#2937
* sshd(8) Cygwin: Change service name to cygsshd to avoid collision
with Microsoft's OpenSSH port.
* Allow building against OpenSSL -dev (3.x)
* Fix a number of build problems against version configurations and
versions of OpenSSL. Including bz#2931 and bz#2921
* Improve warnings in cygwin service setup. bz#2922
* Remove hardcoded service name in cygwin setup. bz#2922
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available as RELEASE_KEY.asc from
the mirror sites.
Reporting Bugs:
OpenSSH 7.9 was released on 2018-10-19. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
http://www.openssh.com/donations.html
Potentially-incompatible changes
This release includes a number of changes that may affect existing
configurations:
* ssh(1), sshd(8): the setting of the new CASignatureAlgorithms
option (see below) bans the use of DSA keys as certificate
authorities.
* sshd(8): the authentication success/failure log message has
changed format slightly. It now includes the certificate
fingerprint (previously it included only key ID and CA key
fingerprint).
Changes since OpenSSH 7.8
This is primarily a bugfix release.
New Features
* ssh(1), sshd(8): allow most port numbers to be specified using
service names from getservbyname(3) (typically /etc/services).
* ssh(1): allow the IdentityAgent configuration directive to accept
environment variable names. This supports the use of multiple
agent sockets without needing to use fixed paths.
* sshd(8): support signalling sessions via the SSH protocol.
A limited subset of signals is supported and only for login or
command sessions (i.e. not subsystems) that were not subject to
a forced command via authorized_keys or sshd_config. bz#1424
* ssh(1): support "ssh -Q sig" to list supported signature options.
Also "ssh -Q help" to show the full set of supported queries.
* ssh(1), sshd(8): add a CASignatureAlgorithms option for the
client and server configs to allow control over which signature
formats are allowed for CAs to sign certificates. For example,
this allows banning CAs that sign certificates using the RSA-SHA1
signature algorithm.
* sshd(8), ssh-keygen(1): allow key revocation lists (KRLs) to
revoke keys specified by SHA256 hash.
* ssh-keygen(1): allow creation of key revocation lists directly
from base64-encoded SHA256 fingerprints. This supports revoking
keys using only the information contained in sshd(8)
authentication log messages.
Bugfixes
* ssh(1), ssh-keygen(1): avoid spurious "invalid format" errors when
attempting to load PEM private keys while using an incorrect
passphrase. bz#2901
* sshd(8): when a channel closed message is received from a client,
close the stderr file descriptor at the same time stdout is
closed. This avoids stuck processes if they were waiting for
stderr to close and were insensitive to stdin/out closing. bz#2863
* ssh(1): allow ForwardX11Timeout=0 to disable the untrusted X11
forwarding timeout and support X11 forwarding indefinitely.
Previously the behaviour of ForwardX11Timeout=0 was undefined.
* sshd(8): when compiled with GSSAPI support, cache supported method
OIDs regardless of whether GSSAPI authentication is enabled in the
main section of sshd_config. This avoids sandbox violations if
GSSAPI authentication was later enabled in a Match block. bz#2107
* sshd(8): do not fail closed when configured with a text key
revocation list that contains a too-short key. bz#2897
* ssh(1): treat connections with ProxyJump specified the same as
ones with a ProxyCommand set with regards to hostname
canonicalisation (i.e. don't try to canonicalise the hostname
unless CanonicalizeHostname is set to 'always'). bz#2896
* ssh(1): fix regression in OpenSSH 7.8 that could prevent public-
key authentication using certificates hosted in a ssh-agent(1)
or against sshd(8) from OpenSSH <7.8.
Portability
* All: support building against the openssl-1.1 API (releases 1.1.0g
and later). The openssl-1.0 API will remain supported at least
until OpenSSL terminates security patch support for that API version.
* sshd(8): allow the futex(2) syscall in the Linux seccomp sandbox;
apparently required by some glibc/OpenSSL combinations.
* sshd(8): handle getgrouplist(3) returning more than
_SC_NGROUPS_MAX groups. Some platforms consider this limit more
as a guideline.
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available as RELEASE_KEY.asc from
the mirror sites.
Reporting Bugs:
OpenSSH 7.8 was released on 2018-08-24. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
http://www.openssh.com/donations.html
Potentially-incompatible changes
This release includes a number of changes that may affect existing
configurations:
* ssh-keygen(1): write OpenSSH format private keys by default
instead of using OpenSSL's PEM format. The OpenSSH format,
supported in OpenSSH releases since 2014 and described in the
PROTOCOL.key file in the source distribution, offers substantially
better protection against offline password guessing and supports
key comments in private keys. If necessary, it is possible to write
old PEM-style keys by adding "-m PEM" to ssh-keygen's arguments
when generating or updating a key.
* sshd(8): remove internal support for S/Key multiple factor
authentication. S/Key may still be used via PAM or BSD auth.
* ssh(1): remove vestigal support for running ssh(1) as setuid. This
used to be required for hostbased authentication and the (long
gone) rhosts-style authentication, but has not been necessary for
a long time. Attempting to execute ssh as a setuid binary, or with
uid != effective uid will now yield a fatal error at runtime.
* sshd(8): the semantics of PubkeyAcceptedKeyTypes and the similar
HostbasedAcceptedKeyTypes options have changed. These now specify
signature algorithms that are accepted for their respective
authentication mechanism, where previously they specified accepted
key types. This distinction matters when using the RSA/SHA2
signature algorithms "rsa-sha2-256", "rsa-sha2-512" and their
certificate counterparts. Configurations that override these
options but omit these algorithm names may cause unexpected
authentication failures (no action is required for configurations
that accept the default for these options).
* sshd(8): the precedence of session environment variables has
changed. ~/.ssh/environment and environment="..." options in
authorized_keys files can no longer override SSH_* variables set
implicitly by sshd.
* ssh(1)/sshd(8): the default IPQoS used by ssh/sshd has changed.
They will now use DSCP AF21 for interactive traffic and CS1 for
bulk. For a detailed rationale, please see the commit message:
https://cvsweb.openbsd.org/log/src/usr.bin/ssh/readconf.c,v#rev1.284
Changes since OpenSSH 7.7
This is primarily a bugfix release.
New Features
* ssh(1)/sshd(8): add new signature algorithms "rsa-sha2-256-cert-
v01@openssh.com" and "rsa-sha2-512-cert-v01@openssh.com" to
explicitly force use of RSA/SHA2 signatures in authentication.
* sshd(8): extend the PermitUserEnvironment option to accept a
whitelist of environment variable names in addition to global
"yes" or "no" settings.
* sshd(8): add a PermitListen directive to sshd_config(5) and a
corresponding permitlisten= authorized_keys option that control
which listen addresses and port numbers may be used by remote
forwarding (ssh -R ...).
* sshd(8): add some countermeasures against timing attacks used for
account validation/enumeration. sshd will enforce a minimum time
or each failed authentication attempt consisting of a global 5ms
minimum plus an additional per-user 0-4ms delay derived from a
host secret.
* sshd(8): add a SetEnv directive to allow an administrator to
explicitly specify environment variables in sshd_config.
Variables set by SetEnv override the default and client-specified
environment.
* ssh(1): add a SetEnv directive to request that the server sets
an environment variable in the session. Similar to the existing
SendEnv option, these variables are set subject to server
configuration.
* ssh(1): allow "SendEnv -PATTERN" to clear environment variables
previously marked for sending to the server. bz#1285
* ssh(1)/sshd(8): make UID available as a %-expansion everywhere
that the username is available currently. bz#2870
* ssh(1): allow setting ProxyJump=none to disable ProxyJump
functionality. bz#2869
Bugfixes
* sshd(8): avoid observable differences in request parsing that could
be used to determine whether a target user is valid.
* all: substantial internal refactoring
* ssh(1)/sshd(8): fix some memory leaks; bz#2366
* ssh(1): fix a pwent clobber (introduced in openssh-7.7) that could
occur during key loading, manifesting as crash on some platforms.
* sshd_config(5): clarify documentation for AuthenticationMethods
option; bz#2663
* ssh(1): ensure that the public key algorithm sent in a
public key SSH_MSG_USERAUTH_REQUEST matches the content of the
signature blob. Previously, these could be inconsistent when a
legacy or non-OpenSSH ssh-agent returned a RSA/SHA1 signature
when asked to make a RSA/SHA2 signature.
* sshd(8): fix failures to read authorized_keys caused by faulty
supplemental group caching. bz#2873
* scp(1): apply umask to directories, fixing potential mkdir/chmod
race when copying directory trees bz#2839
* ssh-keygen(1): return correct exit code when searching for and
hashing known_hosts entries in a single operation; bz#2772
* ssh(1): prefer the ssh binary pointed to via argv[0] to $PATH when
re-executing ssh for ProxyJump. bz#2831
* sshd(8): do not ban PTY allocation when a sshd session is
restricted because the user password is expired as it breaks
password change dialog. (regression in openssh-7.7).
* ssh(1)/sshd(8): fix error reporting from select() failures.
* ssh(1): improve documentation for -w (tunnel) flag, emphasising
that -w implicitly sets Tunnel=point-to-point. bz#2365
* ssh-agent(1): implement EMFILE mitigation for ssh-agent. ssh-agent
will no longer spin when its file descriptor limit is exceeded.
bz#2576
* ssh(1)/sshd(8): disable SSH2_MSG_DEBUG messages for Twisted Conch
clients. Twisted Conch versions that lack a version number in
their identification strings will mishandle these messages when
running on Python 2.x (https://twistedmatrix.com/trac/ticket/9422)
* sftp(1): notify user immediately when underlying ssh process dies
expectedly. bz#2719
* ssh(1)/sshd(8): fix tunnel forwarding; regression in 7.7 release.
bz#2855
* ssh-agent(1): don't kill ssh-agent's listening socket entirely if
it fails to accept(2) a connection. bz#2837
* sshd(8): relax checking of authorized_keys environment="..."
options to allow underscores in variable names (regression
introduced in 7.7). bz#2851
* ssh(1): add some missing options in the configuration dump output
(ssh -G). bz#2835
Portability
* sshd(8): Expose details of completed authentication to PAM auth
modules via SSH_AUTH_INFO_0 in the PAM environment. bz#2408
* Fix compilation problems caused by fights between zlib and OpenSSL
colliding uses of "free_func"
* Improve detection of unsupported compiler options. Recently these
may have manifested as "unsupported -Wl,-z,retpoline" warnings
during linking.
* sshd(8): some sandbox support for Linux/s390 bz#2752.
* regress tests: unbreak key-options.sh test on platforms without
openpty(3). bz#2856
* use getrandom(2) for PRNG seeding when built without OpenSSL.
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available as RELEASE_KEY.asc from
the mirror sites.
Reporting Bugs:
OpenSSH 7.7 was released on 2018-04-02. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
http://www.openssh.com/donations.html
Potentially-incompatible changes
This release includes a number of changes that may affect existing
configurations:
* ssh(1)/sshd(8): Drop compatibility support for some very old SSH
implementations, including ssh.com <=2.* and OpenSSH <= 3.*. These
versions were all released in or before 2001 and predate the final
SSH RFCs. The support in question isn't necessary for RFC-compliant
SSH implementations.
Changes since OpenSSH 7.6
This is primarily a bugfix release.
New Features
* All: Add experimental support for PQC XMSS keys (Extended Hash-
Based Signatures) based on the algorithm described in
https://tools.ietf.org/html/draft-irtf-cfrg-xmss-hash-based-signatures-12
The XMSS signature code is experimental and not compiled in by
default.
* sshd(8): Add a "rdomain" criteria for the sshd_config Match keyword
to allow conditional configuration that depends on which routing
domain a connection was received on (currently supported on OpenBSD
and Linux).
* sshd_config(5): Add an optional rdomain qualifier to the
ListenAddress directive to allow listening on different routing
domains. This is supported only on OpenBSD and Linux at present.
* sshd_config(5): Add RDomain directive to allow the authenticated
session to be placed in an explicit routing domain. This is only
supported on OpenBSD at present.
* sshd(8): Add "expiry-time" option for authorized_keys files to
allow for expiring keys.
* ssh(1): Add a BindInterface option to allow binding the outgoing
connection to an interface's address (basically a more usable
BindAddress)
* ssh(1): Expose device allocated for tun/tap forwarding via a new
%T expansion for LocalCommand. This allows LocalCommand to be used
to prepare the interface.
* sshd(8): Expose the device allocated for tun/tap forwarding via a
new SSH_TUNNEL environment variable. This allows automatic setup of
the interface and surrounding network configuration automatically on
the server.
* ssh(1)/scp(1)/sftp(1): Add URI support to ssh, sftp and scp, e.g.
ssh://user@host or sftp://user@host/path. Additional connection
parameters described in draft-ietf-secsh-scp-sftp-ssh-uri-04 are not
implemented since the ssh fingerprint format in the draft uses the
deprecated MD5 hash with no way to specify the any other algorithm.
* ssh-keygen(1): Allow certificate validity intervals that specify
only a start or stop time (instead of both or neither).
* sftp(1): Allow "cd" and "lcd" commands with no explicit path
argument. lcd will change to the local user's home directory as
usual. cd will change to the starting directory for session (because
the protocol offers no way to obtain the remote user's home
directory). bz#2760
* sshd(8): When doing a config test with sshd -T, only require the
attributes that are actually used in Match criteria rather than (an
incomplete list of) all criteria.
Bugfixes
* ssh(1)/sshd(8): More strictly check signature types during key
exchange against what was negotiated. Prevents downgrade of RSA
signatures made with SHA-256/512 to SHA-1.
* sshd(8): Fix support for client that advertise a protocol version
of "1.99" (indicating that they are prepared to accept both SSHv1 and
SSHv2). This was broken in OpenSSH 7.6 during the removal of SSHv1
support. bz#2810
* ssh(1): Warn when the agent returns a ssh-rsa (SHA1) signature when
a rsa-sha2-256/512 signature was requested. This condition is possible
when an old or non-OpenSSH agent is in use. bz#2799
* ssh-agent(1): Fix regression introduced in 7.6 that caused ssh-agent
to fatally exit if presented an invalid signature request message.
* sshd_config(5): Accept yes/no flag options case-insensitively, as
has been the case in ssh_config(5) for a long time. bz#2664
* ssh(1): Improve error reporting for failures during connection.
Under some circumstances misleading errors were being shown. bz#2814
* ssh-keyscan(1): Add -D option to allow printing of results directly
in SSHFP format. bz#2821
* regress tests: fix PuTTY interop test broken in last release's SSHv1
removal. bz#2823
* ssh(1): Compatibility fix for some servers that erroneously drop the
connection when the IUTF8 (RFC8160) option is sent.
* scp(1): Disable RemoteCommand and RequestTTY in the ssh session
started by scp (sftp was already doing this.)
* ssh-keygen(1): Refuse to create a certificate with an unusable
number of principals.
* ssh-keygen(1): Fatally exit if ssh-keygen is unable to write all the
public key during key generation. Previously it would silently
ignore errors writing the comment and terminating newline.
* ssh(1): Do not modify hostname arguments that are addresses by
automatically forcing them to lower-case. Instead canonicalise them
to resolve ambiguities (e.g. ::0001 => ::1) before they are matched
against known_hosts. bz#2763
* ssh(1): Don't accept junk after "yes" or "no" responses to hostkey
prompts. bz#2803
* sftp(1): Have sftp print a warning about shell cleanliness when
decoding the first packet fails, which is usually caused by shells
polluting stdout of non-interactive startups. bz#2800
* ssh(1)/sshd(8): Switch timers in packet code from using wall-clock
time to monotonic time, allowing the packet layer to better function
over a clock step and avoiding possible integer overflows during
steps.
* Numerous manual page fixes and improvements.
Portability
* sshd(8): Correctly detect MIPS ABI in use at configure time. Fixes
sandbox violations on some environments.
* sshd(8): Remove UNICOS support. The hardware and software are literal
museum pieces and support in sshd is too intrusive to justify
maintaining.
* All: Build and link with "retpoline" flags when available to mitigate
the "branch target injection" style (variant 2) of the Spectre
branch-prediction vulnerability.
* All: Add auto-generated dependency information to Makefile.
* Numerous fixed to the RPM spec files.
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available as RELEASE_KEY.asc from
the mirror sites.
Reporting Bugs:
OpenSSH 7.6 was released on 2017-10-03. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
http://www.openssh.com/donations.html
Potentially-incompatible changes
This release includes a number of changes that may affect existing
configurations:
* ssh(1): delete SSH protocol version 1 support, associated
configuration options and documentation.
* ssh(1)/sshd(8): remove support for the hmac-ripemd160 MAC.
* ssh(1)/sshd(8): remove support for the arcfour, blowfish and CAST
ciphers.
* Refuse RSA keys <1024 bits in length and improve reporting for keys
that do not meet this requirement.
* ssh(1): do not offer CBC ciphers by default.
Changes since OpenSSH 7.5
This is primarily a bugfix release. It also contains substantial
internal refactoring.
Security
* sftp-server(8): in read-only mode, sftp-server was incorrectly
permitting creation of zero-length files. Reported by Michal
Zalewski.
New Features
* ssh(1): add RemoteCommand option to specify a command in the ssh
config file instead of giving it on the client's command line. This
allows the configuration file to specify the command that will be
executed on the remote host.
* sshd(8): add ExposeAuthInfo option that enables writing details of
the authentication methods used (including public keys where
applicable) to a file that is exposed via a $SSH_USER_AUTH
environment variable in the subsequent session.
* ssh(1): add support for reverse dynamic forwarding. In this mode,
ssh will act as a SOCKS4/5 proxy and forward connections
to destinations requested by the remote SOCKS client. This mode
is requested using extended syntax for the -R and RemoteForward
options and, because it is implemented solely at the client,
does not require the server be updated to be supported.
* sshd(8): allow LogLevel directive in sshd_config Match blocks;
bz#2717
* ssh-keygen(1): allow inclusion of arbitrary string or flag
certificate extensions and critical options.
* ssh-keygen(1): allow ssh-keygen to use a key held in ssh-agent as
a CA when signing certificates. bz#2377
* ssh(1)/sshd(8): allow IPQoS=none in ssh/sshd to not set an explicit
ToS/DSCP value and just use the operating system default.
* ssh-add(1): added -q option to make ssh-add quiet on success.
* ssh(1): expand the StrictHostKeyChecking option with two new
settings. The first "accept-new" will automatically accept
hitherto-unseen keys but will refuse connections for changed or
invalid hostkeys. This is a safer subset of the current behaviour
of StrictHostKeyChecking=no. The second setting "off", is a synonym
for the current behaviour of StrictHostKeyChecking=no: accept new
host keys, and continue connection for hosts with incorrect
hostkeys. A future release will change the meaning of
StrictHostKeyChecking=no to the behaviour of "accept-new". bz#2400
* ssh(1): add SyslogFacility option to ssh(1) matching the equivalent
option in sshd(8). bz#2705
Bugfixes
* ssh(1): use HostKeyAlias if specified instead of hostname for
matching host certificate principal names; bz#2728
* sftp(1): implement sorting for globbed ls; bz#2649
* ssh(1): add a user@host prefix to client's "Permission denied"
messages, useful in particular when using "stacked" connections
(e.g. ssh -J) where it's not clear which host is denying. bz#2720
* ssh(1): accept unknown EXT_INFO extension values that contain \0
characters. These are legal, but would previously cause fatal
connection errors if received.
* ssh(1)/sshd(8): repair compression statistics printed at
connection exit
* sftp(1): print '?' instead of incorrect link count (that the
protocol doesn't provide) for remote listings. bz#2710
* ssh(1): return failure rather than fatal() for more cases during
session multiplexing negotiations. Causes the session to fall back
to a non-mux connection if they occur. bz#2707
* ssh(1): mention that the server may send debug messages to explain
public key authentication problems under some circumstances; bz#2709
* Translate OpenSSL error codes to better report incorrect passphrase
errors when loading private keys; bz#2699
* sshd(8): adjust compatibility patterns for WinSCP to correctly
identify versions that implement only the legacy DH group exchange
scheme. bz#2748
* ssh(1): print the "Killed by signal 1" message only at LogLevel
verbose so that it is not shown at the default level; prevents it
from appearing during ssh -J and equivalent ProxyCommand configs.
bz#1906, bz#2744
* ssh-keygen(1): when generating all hostkeys (ssh-keygen -A), clobber
existing keys if they exist but are zero length. zero-length keys
could previously be made if ssh-keygen failed or was interrupted part
way through generating them. bz#2561
* ssh(1): fix pledge(2) violation in the escape sequence "~&" used to
place the current session in the background.
* ssh-keyscan(1): avoid double-close() on file descriptors; bz#2734
* sshd(8): avoid reliance on shared use of pointers shared between
monitor and child sshd processes. bz#2704
* sshd_config(8): document available AuthenticationMethods; bz#2453
* ssh(1): avoid truncation in some login prompts; bz#2768
* sshd(8): Fix various compilations failures, inc bz#2767
* ssh(1): make "--" before the hostname terminate argument processing
after the hostname too.
* ssh-keygen(1): switch from aes256-cbc to aes256-ctr for encrypting
new-style private keys. Fixes problems related to private key
handling for no-OpenSSL builds. bz#2754
* ssh(1): warn and do not attempt to use keys when the public and
private halves do not match. bz#2737
* sftp(1): don't print verbose error message when ssh disconnects
from under sftp. bz#2750
* sshd(8): fix keepalive scheduling problem: activity on a forwarded
port from preventing the keepalive from being sent; bz#2756
* sshd(8): when started without root privileges, don't require the
privilege separation user or path to exist. Makes running the
regression tests easier without touching the filesystem.
* Make integrity.sh regression tests more robust against timeouts.
bz#2658
* ssh(1)/sshd(8): correctness fix for channels implementation: accept
channel IDs greater than 0x7FFFFFFF.
Portability
* sshd(9): drop two more privileges in the Solaris sandbox:
PRIV_DAX_ACCESS and PRIV_SYS_IB_INFO; bz#2723
* sshd(8): expose list of completed authentication methods to PAM
via the SSH_AUTH_INFO_0 PAM environment variable. bz#2408
* ssh(1)/sshd(8): fix several problems in the tun/tap forwarding code,
mostly to do with host/network byte order confusion. bz#2735
* Add --with-cflags-after and --with-ldflags-after configure flags to
allow setting CFLAGS/LDFLAGS after configure has completed. These
are useful for setting sanitiser/fuzzing options that may interfere
with configure's operation.
* sshd(8): avoid Linux seccomp violations on ppc64le over the
socketcall syscall.
* Fix use of ldns when using ldns-config; bz#2697
* configure: set cache variables when cross-compiling. The cross-
compiling fallback message was saying it assumed the test passed,
but it wasn't actually set the cache variables and this would
cause later tests to fail.
* Add clang libFuzzer harnesses for public key parsing and signature
verification.
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available as RELEASE_KEY.asc from
the mirror sites.
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de
Raadt, Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre,
Tim Rice and Ben Lindstrom.
OpenSSH 7.5 was released on 2017-03-20. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support. OpenSSH also includes
transitional support for the legacy SSH 1.3 and 1.5 protocols
that may be enabled at compile-time.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
http://www.openssh.com/donations.html
Future deprecation notice
We plan on retiring more legacy cryptography in future releases,
specifically:
* In the next major release (expected June-August), removing remaining
support for the SSH v.1 protocol (currently client-only and compile-
time disabled).
* In the same release, removing support for Blowfish and RC4 ciphers
and the RIPE-MD160 HMAC. (These are currently run-time disabled).
* In the same release, removing the remaining CBC ciphers from being
offered by default in the client (These have not been offered in
sshd by default for several years).
* Refusing all RSA keys smaller than 1024 bits (the current minimum
is 768 bits)
This list reflects our current intentions, but please check the final
release notes for future releases.
Potentially-incompatible changes
This release includes a number of changes that may affect existing
configurations:
* This release deprecates the sshd_config UsePrivilegeSeparation
option, thereby making privilege separation mandatory. Privilege
separation has been on by default for almost 15 years and
sandboxing has been on by default for almost the last five.
* The format of several log messages emitted by the packet code has
changed to include additional information about the user and
their authentication state. Software that monitors ssh/sshd logs
may need to account for these changes. For example:
Connection closed by user x 1.1.1.1 port 1234 [preauth]
Connection closed by authenticating user x 10.1.1.1 port 1234 [preauth]
Connection closed by invalid user x 1.1.1.1 port 1234 [preauth]
Affected messages include connection closure, timeout, remote
disconnection, negotiation failure and some other fatal messages
generated by the packet code.
* [Portable OpenSSH only] This version removes support for building
against OpenSSL versions prior to 1.0.1. OpenSSL stopped supporting
versions prior to 1.0.1 over 12 months ago (i.e. they no longer
receive fixes for security bugs).
Changes since OpenSSH 7.4
This is a bugfix release.
Security
* ssh(1), sshd(8): Fix weakness in CBC padding oracle countermeasures
that allowed a variant of the attack fixed in OpenSSH 7.3 to proceed.
Note that the OpenSSH client disables CBC ciphers by default, sshd
offers them as lowest-preference options and will remove them by
default entriely in the next release. Reported by Jean Paul
Degabriele, Kenny Paterson, Martin Albrecht and Torben Hansen of
Royal Holloway, University of London.
* sftp-client(1): [portable OpenSSH only] On Cygwin, a client making
a recursive file transfer could be manipulated by a hostile server to
perform a path-traversal attack. creating or modifying files outside
of the intended target directory. Reported by Jann Horn of Google
Project Zero.
New Features
* ssh(1), sshd(8): Support "=-" syntax to easily remove methods from
algorithm lists, e.g. Ciphers=-*cbc. bz#2671
Bugfixes
* sshd(1): Fix NULL dereference crash when key exchange start
messages are sent out of sequence.
* ssh(1), sshd(8): Allow form-feed characters to appear in
configuration files.
* sshd(8): Fix regression in OpenSSH 7.4 support for the
server-sig-algs extension, where SHA2 RSA signature methods were
not being correctly advertised. bz#2680
* ssh(1), ssh-keygen(1): Fix a number of case-sensitivity bugs in
known_hosts processing. bz#2591 bz#2685
* ssh(1): Allow ssh to use certificates accompanied by a private key
file but no corresponding plain *.pub public key. bz#2617
* ssh(1): When updating hostkeys using the UpdateHostKeys option,
accept RSA keys if HostkeyAlgorithms contains any RSA keytype.
Previously, ssh could ignore RSA keys when only the ssh-rsa-sha2-*
methods were enabled in HostkeyAlgorithms and not the old ssh-rsa
method. bz#2650
* ssh(1): Detect and report excessively long configuration file
lines. bz#2651
* Merge a number of fixes found by Coverity and reported via Redhat
and FreeBSD. Includes fixes for some memory and file descriptor
leaks in error paths. bz#2687
* ssh-keyscan(1): Correctly hash hosts with a port number. bz#2692
* ssh(1), sshd(8): When logging long messages to stderr, don't truncate
"\r\n" if the length of the message exceeds the buffer. bz#2688
* ssh(1): Fully quote [host]:port in generated ProxyJump/-J command-
line; avoid confusion over IPv6 addresses and shells that treat
square bracket characters specially.
* ssh-keygen(1): Fix corruption of known_hosts when running
"ssh-keygen -H" on a known_hosts containing already-hashed entries.
* Fix various fallout and sharp edges caused by removing SSH protocol
1 support from the server, including the server banner string being
incorrectly terminated with only \n (instead of \r\n), confusing
error messages from ssh-keyscan bz#2583 and a segfault in sshd
if protocol v.1 was enabled for the client and sshd_config
contained references to legacy keys bz#2686.
* ssh(1), sshd(8): Free fd_set on connection timeout. bz#2683
* sshd(8): Fix Unix domain socket forwarding for root (regression in
OpenSSH 7.4).
* sftp(1): Fix division by zero crash in "df" output when server
returns zero total filesystem blocks/inodes.
* ssh(1), ssh-add(1), ssh-keygen(1), sshd(8): Translate OpenSSL errors
encountered during key loading to more meaningful error codes.
bz#2522 bz#2523
* ssh-keygen(1): Sanitise escape sequences in key comments sent to
printf but preserve valid UTF-8 when the locale supports it;
bz#2520
* ssh(1), sshd(8): Return reason for port forwarding failures where
feasible rather than always "administratively prohibited". bz#2674
* sshd(8): Fix deadlock when AuthorizedKeysCommand or
AuthorizedPrincipalsCommand produces a lot of output and a key is
matched early. bz#2655
* Regression tests: several reliability fixes. bz#2654 bz#2658 bz#2659
* ssh(1): Fix typo in ~C error message for bad port forward
cancellation. bz#2672
* ssh(1): Show a useful error message when included config files
can't be opened; bz#2653
* sshd(8): Make sshd set GSSAPIStrictAcceptorCheck=yes as the manual page
(previously incorrectly) advertised. bz#2637
* sshd_config(5): Repair accidentally-deleted mention of %k token
in AuthorizedKeysCommand; bz#2656
* sshd(8): Remove vestiges of previously removed LOGIN_PROGRAM; bz#2665
* ssh-agent(1): Relax PKCS#11 whitelist to include libexec and
common 32-bit compatibility library directories.
* sftp-client(1): Fix non-exploitable integer overflow in SSH2_FXP_NAME
response handling.
* ssh-agent(1): Fix regression in 7.4 of deleting PKCS#11-hosted
keys. It was not possible to delete them except by specifying
their full physical path. bz#2682
Portability
* sshd(8): Avoid sandbox errors for Linux S390 systems using an ICA
crypto coprocessor.
* sshd(8): Fix non-exploitable weakness in seccomp-bpf sandbox arg
inspection.
* ssh(1): Fix X11 forwarding on OSX where X11 was being started by
launchd. bz#2341
* ssh-keygen(1), ssh(1), sftp(1): Fix output truncation for various that
contain non-printable characters where the codeset in use is ASCII.
* build: Fix builds that attempt to link a kerberised libldns. bz#2603
* build: Fix compilation problems caused by unconditionally defining
_XOPEN_SOURCE in wide character detection.
* sshd(8): Fix sandbox violations for clock_gettime VSDO syscall
fallback on some Linux/X32 kernels. bz#2142
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available as RELEASE_KEY.asc from
the mirror sites.
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de
Raadt, Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre,
Tim Rice and Ben Lindstrom.
OpenSSH 7.4 was released on 2016-12-19. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support. OpenSSH also includes
transitional support for the legacy SSH 1.3 and 1.5 protocols
that may be enabled at compile-time.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
http://www.openssh.com/donations.html
Future deprecation notice
We plan on retiring more legacy cryptography in future releases,
specifically:
* In approximately August 2017, removing remaining support for the
SSH v.1 protocol (client-only and currently compile-time disabled).
* In the same release, removing support for Blowfish and RC4 ciphers
and the RIPE-MD160 HMAC. (These are currently run-time disabled).
* Refusing all RSA keys smaller than 1024 bits (the current minimum
is 768 bits)
* The next release of OpenSSH will remove support for running sshd(8)
with privilege separation disabled.
* The next release of portable OpenSSH will remove support for
OpenSSL version prior to 1.0.1.
This list reflects our current intentions, but please check the final
release notes for future releases.
Potentially-incompatible changes
This release includes a number of changes that may affect existing
configurations:
* This release removes server support for the SSH v.1 protocol.
* ssh(1): Remove 3des-cbc from the client's default proposal. 64-bit
block ciphers are not safe in 2016 and we don't want to wait until
attacks like SWEET32 are extended to SSH. As 3des-cbc was the
only mandatory cipher in the SSH RFCs, this may cause problems
connecting to older devices using the default configuration,
but it's highly likely that such devices already need explicit
configuration for key exchange and hostkey algorithms already
anyway.
* sshd(8): Remove support for pre-authentication compression.
Doing compression early in the protocol probably seemed reasonable
in the 1990s, but today it's clearly a bad idea in terms of both
cryptography (cf. multiple compression oracle attacks in TLS) and
attack surface. Pre-auth compression support has been disabled by
default for >10 years. Support remains in the client.
* ssh-agent will refuse to load PKCS#11 modules outside a whitelist
of trusted paths by default. The path whitelist may be specified
at run-time.
* sshd(8): When a forced-command appears in both a certificate and
an authorized keys/principals command= restriction, sshd will now
refuse to accept the certificate unless they are identical.
The previous (documented) behaviour of having the certificate
forced-command override the other could be a bit confusing and
error-prone.
* sshd(8): Remove the UseLogin configuration directive and support
for having /bin/login manage login sessions.
Changes since OpenSSH 7.3
This is primarily a bugfix release.
Security
* ssh-agent(1): Will now refuse to load PKCS#11 modules from paths
outside a trusted whitelist (run-time configurable). Requests to
load modules could be passed via agent forwarding and an attacker
could attempt to load a hostile PKCS#11 module across the forwarded
agent channel: PKCS#11 modules are shared libraries, so this would
result in code execution on the system running the ssh-agent if the
attacker has control of the forwarded agent-socket (on the host
running the sshd server) and the ability to write to the filesystem
of the host running ssh-agent (usually the host running the ssh
client). Reported by Jann Horn of Project Zero.
* sshd(8): When privilege separation is disabled, forwarded Unix-
domain sockets would be created by sshd(8) with the privileges of
'root' instead of the authenticated user. This release refuses
Unix-domain socket forwarding when privilege separation is disabled
(Privilege separation has been enabled by default for 14 years).
Reported by Jann Horn of Project Zero.
* sshd(8): Avoid theoretical leak of host private key material to
privilege-separated child processes via realloc() when reading
keys. No such leak was observed in practice for normal-sized keys,
nor does a leak to the child processes directly expose key material
to unprivileged users. Reported by Jann Horn of Project Zero.
* sshd(8): The shared memory manager used by pre-authentication
compression support had a bounds checks that could be elided by
some optimising compilers. Additionally, this memory manager was
incorrectly accessible when pre-authentication compression was
disabled. This could potentially allow attacks against the
privileged monitor process from the sandboxed privilege-separation
process (a compromise of the latter would be required first).
This release removes support for pre-authentication compression
from sshd(8). Reported by Guido Vranken using the Stack unstable
optimisation identification tool (http://css.csail.mit.edu/stack/)
* sshd(8): Fix denial-of-service condition where an attacker who
sends multiple KEXINIT messages may consume up to 128MB per
connection. Reported by Shi Lei of Gear Team, Qihoo 360.
* sshd(8): Validate address ranges for AllowUser and DenyUsers
directives at configuration load time and refuse to accept invalid
ones. It was previously possible to specify invalid CIDR address
ranges (e.g. user@127.1.2.3/55) and these would always match,
possibly resulting in granting access where it was not intended.
Reported by Laurence Parry.
New Features
* ssh(1): Add a proxy multiplexing mode to ssh(1) inspired by the
version in PuTTY by Simon Tatham. This allows a multiplexing
client to communicate with the master process using a subset of
the SSH packet and channels protocol over a Unix-domain socket,
with the main process acting as a proxy that translates channel
IDs, etc. This allows multiplexing mode to run on systems that
lack file- descriptor passing (used by current multiplexing
code) and potentially, in conjunction with Unix-domain socket
forwarding, with the client and multiplexing master process on
different machines. Multiplexing proxy mode may be invoked using
"ssh -O proxy ..."
* sshd(8): Add a sshd_config DisableForwarding option that disables
X11, agent, TCP, tunnel and Unix domain socket forwarding, as well
as anything else we might implement in the future. Like the
'restrict' authorized_keys flag, this is intended to be a simple
and future-proof way of restricting an account.
* sshd(8), ssh(1): Support the "curve25519-sha256" key exchange
method. This is identical to the currently-supported method named
"curve25519-sha256@libssh.org".
* sshd(8): Improve handling of SIGHUP by checking to see if sshd is
already daemonised at startup and skipping the call to daemon(3)
if it is. This ensures that a SIGHUP restart of sshd(8) will
retain the same process-ID as the initial execution. sshd(8) will
also now unlink the PidFile prior to SIGHUP restart and re-create
it after a successful restart, rather than leaving a stale file in
the case of a configuration error. bz#2641
* sshd(8): Allow ClientAliveInterval and ClientAliveCountMax
directives to appear in sshd_config Match blocks.
* sshd(8): Add %-escapes to AuthorizedPrincipalsCommand to match
those supported by AuthorizedKeysCommand (key, key type,
fingerprint, etc.) and a few more to provide access to the
contents of the certificate being offered.
* Added regression tests for string matching, address matching and
string sanitisation functions.
* Improved the key exchange fuzzer harness.
Bugfixes
* ssh(1): Allow IdentityFile to successfully load and use
certificates that have no corresponding bare public key. bz#2617
certificate id_rsa-cert.pub (and no id_rsa.pub).
* ssh(1): Fix public key authentication when multiple
authentication is in use and publickey is not just the first
method attempted. bz#2642
* regress: Allow the PuTTY interop tests to run unattended. bz#2639
* ssh-agent(1), ssh(1): improve reporting when attempting to load
keys from PKCS#11 tokens with fewer useless log messages and more
detail in debug messages. bz#2610
* ssh(1): When tearing down ControlMaster connections, don't
pollute stderr when LogLevel=quiet.
* sftp(1): On ^Z wait for underlying ssh(1) to suspend before
suspending sftp(1) to ensure that ssh(1) restores the terminal mode
correctly if suspended during a password prompt.
* ssh(1): Avoid busy-wait when ssh(1) is suspended during a password
prompt.
* ssh(1), sshd(8): Correctly report errors during sending of ext-
info messages.
* sshd(8): fix NULL-deref crash if sshd(8) received an out-of-
sequence NEWKEYS message.
* sshd(8): Correct list of supported signature algorithms sent in
the server-sig-algs extension. bz#2547
* sshd(8): Fix sending ext_info message if privsep is disabled.
* sshd(8): more strictly enforce the expected ordering of privilege
separation monitor calls used for authentication and allow them
only when their respective authentication methods are enabled
in the configuration
* sshd(8): Fix uninitialised optlen in getsockopt() call; harmless
on Unix/BSD but potentially crashy on Cygwin.
* Fix false positive reports caused by explicit_bzero(3) not being
recognised as a memory initialiser when compiled with
-fsanitize-memory.
* sshd_config(5): Use 2001:db8::/32, the official IPv6 subnet for
configuration examples.
Portability
* On environments configured with Turkish locales, fall back to the
C/POSIX locale to avoid errors in configuration parsing caused by
that locale's unique handling of the letters 'i' and 'I'. bz#2643
* sftp-server(8), ssh-agent(1): Deny ptrace on OS X using
ptrace(PT_DENY_ATTACH, ..)
* ssh(1), sshd(8): Unbreak AES-CTR ciphers on old (~0.9.8) OpenSSL.
* Fix compilation for libcrypto compiled without RIPEMD160 support.
* contrib: Add a gnome-ssh-askpass3 with GTK+3 support. bz#2640
* sshd(8): Improve PRNG reseeding across privilege separation and
force libcrypto to obtain a high-quality seed before chroot or
sandboxing.
* All: Explicitly test for broken strnvis. NetBSD added an strnvis
and unfortunately made it incompatible with the existing one in
OpenBSD and Linux's libbsd (the former having existed for over ten
years). Try to detect this mess, and assume the only safe option
if we're cross compiling.
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available as RELEASE_KEY.asc from
the mirror sites.
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de
Raadt, Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre,
Tim Rice and Ben Lindstrom.
OpenSSH 7.3 was released on 2016-08-01. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support. OpenSSH also includes
transitional support for the legacy SSH 1.3 and 1.5 protocols
that may be enabled at compile-time.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
http://www.openssh.com/donations.html
Future deprecation notice
We plan on retiring more legacy cryptography in a near-future
release, specifically:
* Refusing all RSA keys smaller than 1024 bits (the current minimum
is 768 bits)
* Removing server-side support for the SSH v.1 protocol (currently
compile-time disabled).
* In approximately 1 year, removing all support for the SSH v.1
protocol (currently compile-time disabled).
This list reflects our current intentions, but please check the final
release notes for future releases.
Changes since OpenSSH 7.2
This is primarily a bugfix release.
Security
* sshd(8): Mitigate a potential denial-of-service attack against
the system's crypt(3) function via sshd(8). An attacker could
send very long passwords that would cause excessive CPU use in
crypt(3). sshd(8) now refuses to accept password authentication
requests of length greater than 1024 characters. Independently
reported by Tomas Kuthan (Oracle), Andres Rojas and Javier Nieto.
* sshd(8): Mitigate timing differences in password authentication
that could be used to discern valid from invalid account names
when long passwords were sent and particular password hashing
algorithms are in use on the server. CVE-2016-6210, reported by
EddieEzra.Harari at verint.com
* ssh(1), sshd(8): Fix observable timing weakness in the CBC padding
oracle countermeasures. Reported by Jean Paul Degabriele, Kenny
Paterson, Torben Hansen and Martin Albrecht. Note that CBC ciphers
are disabled by default and only included for legacy compatibility.
* ssh(1), sshd(8): Improve operation ordering of MAC verification for
Encrypt-then-MAC (EtM) mode transport MAC algorithms to verify the
MAC before decrypting any ciphertext. This removes the possibility
of timing differences leaking facts about the plaintext, though no
such leakage has been observed. Reported by Jean Paul Degabriele,
Kenny Paterson, Torben Hansen and Martin Albrecht.
* sshd(8): (portable only) Ignore PAM environment vars when
UseLogin=yes. If PAM is configured to read user-specified
environment variables and UseLogin=yes in sshd_config, then a
hostile local user may attack /bin/login via LD_PRELOAD or
similar environment variables set via PAM. CVE-2015-8325,
found by Shayan Sadigh.
New Features
* ssh(1): Add a ProxyJump option and corresponding -J command-line
flag to allow simplified indirection through a one or more SSH
bastions or "jump hosts".
* ssh(1): Add an IdentityAgent option to allow specifying specific
agent sockets instead of accepting one from the environment.
* ssh(1): Allow ExitOnForwardFailure and ClearAllForwardings to be
optionally overridden when using ssh -W. bz#2577
* ssh(1), sshd(8): Implement support for the IUTF8 terminal mode as
per draft-sgtatham-secsh-iutf8-00.
* ssh(1), sshd(8): Add support for additional fixed Diffie-Hellman
2K, 4K and 8K groups from draft-ietf-curdle-ssh-kex-sha2-03.
* ssh-keygen(1), ssh(1), sshd(8): support SHA256 and SHA512 RSA
signatures in certificates;
* ssh(1): Add an Include directive for ssh_config(5) files.
* ssh(1): Permit UTF-8 characters in pre-authentication banners sent
from the server. bz#2058
Bugfixes
* ssh(1), sshd(8): Reduce the syslog level of some relatively common
protocol events from LOG_CRIT. bz#2585
* sshd(8): Refuse AuthenticationMethods="" in configurations and
accept AuthenticationMethods=any for the default behaviour of not
requiring multiple authentication. bz#2398
* sshd(8): Remove obsolete and misleading "POSSIBLE BREAK-IN
ATTEMPT!" message when forward and reverse DNS don't match. bz#2585
* ssh(1): Close ControlPersist background process stderr except
in debug mode or when logging to syslog. bz#1988
* misc: Make PROTOCOL description for direct-streamlocal@openssh.com
channel open messages match deployed code. bz#2529
* ssh(1): Deduplicate LocalForward and RemoteForward entries to fix
failures when both ExitOnForwardFailure and hostname
canonicalisation are enabled. bz#2562
* sshd(8): Remove fallback from moduli to obsolete "primes" file
that was deprecated in 2001. bz#2559.
* sshd_config(5): Correct description of UseDNS: it affects ssh
hostname processing for authorized_keys, not known_hosts; bz#2554
* ssh(1): Fix authentication using lone certificate keys in an agent
without corresponding private keys on the filesystem. bz#2550
* sshd(8): Send ClientAliveInterval pings when a time-based
RekeyLimit is set; previously keepalive packets were not being
sent. bz#2252
Portability
* ssh(1), sshd(8): Fix compilation by automatically disabling ciphers
not supported by OpenSSL. bz#2466
* misc: Fix compilation failures on some versions of AIX's compiler
related to the definition of the VA_COPY macro. bz#2589
* sshd(8): Whitelist more architectures to enable the seccomp-bpf
sandbox. bz#2590
* ssh-agent(1), sftp-server(8): Disable process tracing on Solaris
using setpflags(__PROC_PROTECT, ...). bz#2584
* sshd(8): On Solaris, don't call Solaris setproject() with
UsePAM=yes it's PAM's responsibility. bz#2425
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available as RELEASE_KEY.asc from
the mirror sites.
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de
Raadt, Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre,
Tim Rice and Ben Lindstrom.
Portable OpenSSH 7.2p2 was released on 2016-03-10. It will be available
from the mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support. OpenSSH also includes
transitional support for the legacy SSH 1.3 and 1.5 protocols that
may be enabled at compile-time.
Once again, we would like to thank the OpenSSH community for
their continued support of the project, especially those who
contributed code or patches, reported bugs, tested snapshots or
donated to the project. More information on donations may be found
at: http://www.openssh.com/donations.html
Changes since OpenSSH 7.2p1
This release fixes a security bug:
* sshd(8): sanitise X11 authentication credentials to avoid xauth
command injection when X11Forwarding is enabled.
Full details of the vulnerability are available at:
http://www.openssh.com/txt/x11fwd.adv
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available as RELEASE_KEY.asc from
the mirror sites.
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de
Raadt, Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre,
Tim Rice and Ben Lindstrom.
OpenSSH 7.2 was released on 2016-02-29. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support. OpenSSH also includes
transitional support for the legacy SSH 1.3 and 1.5 protocols
that may be enabled at compile-time.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
http://www.openssh.com/donations.html
Future deprecation notice
We plan on retiring more legacy cryptography in a near-future
release, specifically:
* Refusing all RSA keys smaller than 1024 bits (the current minimum
is 768 bits)
This list reflects our current intentions, but please check the final
release notes for future releases.
Potentially-incompatible changes
This release disables a number of legacy cryptographic algorithms
by default in ssh:
* Several ciphers blowfish-cbc, cast128-cbc, all arcfour variants
and the rijndael-cbc aliases for AES.
* MD5-based and truncated HMAC algorithms.
These algorithms are already disabled by default in sshd.
Changes since OpenSSH 7.1p2
This is primarily a bugfix release.
Security
* ssh(1), sshd(8): remove unfinished and unused roaming code (was
already forcibly disabled in OpenSSH 7.1p2).
* ssh(1): eliminate fallback from untrusted X11 forwarding to
trusted forwarding when the X server disables the SECURITY
extension.
* ssh(1), sshd(8): increase the minimum modulus size supported for
diffie-hellman-group-exchange to 2048 bits.
* sshd(8): pre-auth sandboxing is now enabled by default (previous
releases enabled it for new installations via sshd_config).
New Features
* all: add support for RSA signatures using SHA-256/512 hash
algorithms based on draft-rsa-dsa-sha2-256-03.txt and
draft-ssh-ext-info-04.txt.
* ssh(1): Add an AddKeysToAgent client option which can be set to
'yes', 'no', 'ask', or 'confirm', and defaults to 'no'. When
enabled, a private key that is used during authentication will be
added to ssh-agent if it is running (with confirmation enabled if
set to 'confirm').
* sshd(8): add a new authorized_keys option "restrict" that includes
all current and future key restrictions (no-*-forwarding, etc.).
Also add permissive versions of the existing restrictions, e.g.
"no-pty" -> "pty". This simplifies the task of setting up
restricted keys and ensures they are maximally-restricted,
regardless of any permissions we might implement in the future.
* ssh(1): add ssh_config CertificateFile option to explicitly list
certificates. bz#2436
* ssh-keygen(1): allow ssh-keygen to change the key comment for all
supported formats.
* ssh-keygen(1): allow fingerprinting from standard input, e.g.
"ssh-keygen -lf -"
* ssh-keygen(1): allow fingerprinting multiple public keys in a
file, e.g. "ssh-keygen -lf ~/.ssh/authorized_keys" bz#1319
* sshd(8): support "none" as an argument for sshd_config
Foreground and ChrootDirectory. Useful inside Match blocks to
override a global default. bz#2486
* ssh-keygen(1): support multiple certificates (one per line) and
reading from standard input (using "-f -") for "ssh-keygen -L"
* ssh-keyscan(1): add "ssh-keyscan -c ..." flag to allow fetching
certificates instead of plain keys.
* ssh(1): better handle anchored FQDNs (e.g. 'cvs.openbsd.org.') in
hostname canonicalisation - treat them as already canonical and
remove the trailing '.' before matching ssh_config.
Bugfixes
* sftp(1): existing destination directories should not terminate
recursive uploads (regression in openssh 6.8) bz#2528
* ssh(1), sshd(8): correctly send back SSH2_MSG_UNIMPLEMENTED
replies to unexpected messages during key exchange. bz#2949
* ssh(1): refuse attempts to set ConnectionAttempts=0, which does
not make sense and would cause ssh to print an uninitialised stack
variable. bz#2500
* ssh(1): fix errors when attempting to connect to scoped IPv6
addresses with hostname canonicalisation enabled.
* sshd_config(5): list a couple more options usable in Match blocks.
bz#2489
* sshd(8): fix "PubkeyAcceptedKeyTypes +..." inside a Match block.
* ssh(1): expand tilde characters in filenames passed to -i options
before checking whether or not the identity file exists. Avoids
confusion for cases where shell doesn't expand (e.g. "-i /file"
vs. "-i/file"). bz#2481
* ssh(1): do not prepend "exec" to the shell command run by "Match
exec" in a config file, which could cause some commands to fail
in certain environments. bz#2471
* ssh-keyscan(1): fix output for multiple hosts/addrs on one line
when host hashing or a non standard port is in use bz#2479
* sshd(8): skip "Could not chdir to home directory" message when
ChrootDirectory is active. bz#2485
* ssh(1): include PubkeyAcceptedKeyTypes in ssh -G config dump.
* sshd(8): avoid changing TunnelForwarding device flags if they are
already what is needed; makes it possible to use tun/tap
networking as non-root user if device permissions and interface
flags are pre-established
* ssh(1), sshd(8): RekeyLimits could be exceeded by one packet.
bz#2521
* ssh(1): fix multiplexing master failure to notice client exit.
* ssh(1), ssh-agent(1): avoid fatal() for PKCS11 tokens that present
empty key IDs. bz#1773
* sshd(8): avoid printf of NULL argument. bz#2535
* ssh(1), sshd(8): allow RekeyLimits larger than 4GB. bz#2521
* ssh-keygen(1): sshd(8): fix several bugs in (unused) KRL signature
support.
* ssh(1), sshd(8): fix connections with peers that use the key
exchange guess feature of the protocol. bz#2515
* sshd(8): include remote port number in log messages. bz#2503
* ssh(1): don't try to load SSHv1 private key when compiled without
SSHv1 support. bz#2505
* ssh-agent(1), ssh(1): fix incorrect error messages during key
loading and signing errors. bz#2507
* ssh-keygen(1): don't leave empty temporary files when performing
known_hosts file edits when known_hosts doesn't exist.
* sshd(8): correct packet format for tcpip-forward replies for
requests that don't allocate a port bz#2509
* ssh(1), sshd(8): fix possible hang on closed output. bz#2469
* ssh(1): expand %i in ControlPath to UID. bz#2449
* ssh(1), sshd(8): fix return type of openssh_RSA_verify. bz#2460
* ssh(1), sshd(8): fix some option parsing memory leaks. bz#2182
* ssh(1): add a some debug output before DNS resolution; it's a
place where ssh could previously silently stall in cases of
unresponsive DNS servers. bz#2433
* ssh(1): remove spurious newline in visual hostkey. bz#2686
* ssh(1): fix printing (ssh -G ...) of HostKeyAlgorithms=+...
* ssh(1): fix expansion of HostkeyAlgorithms=+...
Documentation
* ssh_config(5), sshd_config(5): update default algorithm lists to
match current reality. bz#2527
* ssh(1): mention -Q key-plain and -Q key-cert query options.
bz#2455
* sshd_config(8): more clearly describe what AuthorizedKeysFile=none
does.
* ssh_config(5): better document ExitOnForwardFailure. bz#2444
* sshd(5): mention internal DH-GEX fallback groups in manual.
bz#2302
* sshd_config(5): better description for MaxSessions option.
bz#2531
Portability
* ssh(1), sftp-server(8), ssh-agent(1), sshd(8): Support Illumos/
Solaris fine-grained privileges. Including a pre-auth privsep
sandbox and several pledge() emulations. bz#2511
* Renovate redhat/openssh.spec, removing deprecated options and
syntax.
* configure: allow --without-ssl-engine with --without-openssl
* sshd(8): fix multiple authentication using S/Key. bz#2502
* sshd(8): read back from libcrypto RAND_* before dropping
privileges. Avoids sandboxing violations with BoringSSL.
* Fix name collision with system-provided glob(3) functions.
bz#2463
* Adapt Makefile to use ssh-keygen -A when generating host keys.
bz#2459
* configure: correct default value for --with-ssh1 bz#2457
* configure: better detection of _res symbol bz#2259
* support getrandom() syscall on Linux
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available as RELEASE_KEY.asc from
the mirror sites.
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de
Raadt, Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre,
Tim Rice and Ben Lindstrom.
OpenSSH 7.1p2 was released on 2016-01-14. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support. OpenSSH also includes
transitional support for the legacy SSH 1.3 and 1.5 protocols
that may be enabled at compile-time.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
http://www.openssh.com/donations.html
Changes since OpenSSH 7.1p1
* SECURITY: ssh(1): The OpenSSH client code between 5.4 and 7.1
contains experimental support for resuming SSH-connections (roaming).
The matching server code has never been shipped, but the client
code was enabled by default and could be tricked by a malicious
server into leaking client memory to the server, including private
client user keys.
The authentication of the server host key prevents exploitation
by a man-in-the-middle, so this information leak is restricted
to connections to malicious or compromised servers.
MITIGATION: For OpenSSH >= 5.4 the vulnerable code in the client
can be completely disabled by adding 'UseRoaming no' to the global
ssh_config(5) file, or to user configuration in ~/.ssh/config,
or by passing -oUseRoaming=no on the command line.
PATCH: See below for a patch to disable this feature (Disabling
Roaming in the Source Code).
This problem was reported by the Qualys Security Advisory team.
* SECURITY: Fix an out of-bound read access in the packet handling
code. Reported by Ben Hawkes.
* PROTOCOL: Correctly interpret the 'first_kex_follows' option during
the initial key exchange. Reported by Matt Johnston.
* Further use of explicit_bzero has been added in various buffer
handling code paths to guard against compilers aggressively
doing dead-store removal.
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available as RELEASE_KEY.asc from
the mirror sites.
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
Disabling Roaming in the Source Code:
--- readconf.c 30 Jul 2015 00:01:34 -0000 1.239
+++ readconf.c 13 Jan 2016 23:17:23 -0000
@@ -1648,7 +1648,7 @@ initialize_options(Options * options)
options->tun_remote = -1;
options->local_command = NULL;
options->permit_local_command = -1;
- options->use_roaming = -1;
+ options->use_roaming = 0;
options->visual_host_key = -1;
options->ip_qos_interactive = -1;
options->ip_qos_bulk = -1;
@@ -1819,8 +1819,7 @@ fill_default_options(Options * options)
options->tun_remote = SSH_TUNID_ANY;
if (options->permit_local_command == -1)
options->permit_local_command = 0;
- if (options->use_roaming == -1)
- options->use_roaming = 1;
+ options->use_roaming = 0;
if (options->visual_host_key == -1)
options->visual_host_key = 0;
if (options->ip_qos_interactive == -1)
--- ssh.c 30 Jul 2015 00:01:34 -0000 1.420
+++ ssh.c 13 Jan 2016 23:17:23 -0000
@@ -1882,9 +1882,6 @@ ssh_session2(void)
fork_postauth();
}
- if (options.use_roaming)
request\_roaming();
- return client_loop(tty_flag, tty_flag ?
options.escape_char : SSH_ESCAPECHAR_NONE, id);
}
OpenSSH 7.1 was released on 2015-08-21. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support. OpenSSH also includes
transitional support for the legacy SSH 1.3 and 1.5 protocols
that may be enabled at compile-time.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
http://www.openssh.com/donations.html
Future deprecation notice
We plan on retiring more legacy cryptography in the next release
including:
* Refusing all RSA keys smaller than 1024 bits (the current minimum
is 768 bits)
* Several ciphers will be disabled by default: blowfish-cbc,
cast128-cbc, all arcfour variants and the rijndael-cbc aliases
for AES.
* MD5-based HMAC algorithms will be disabled by default.
This list reflects our current intentions, but please check the final
release notes for OpenSSH 7.2 when it is released.
Changes since OpenSSH 7.0
This is a bugfix release.
Security
* sshd(8): OpenSSH 7.0 contained a logic error in PermitRootLogin=
prohibit-password/without-password that could, depending on
compile-time configuration, permit password authentication to
root while preventing other forms of authentication. This problem
was reported by Mantas Mikulenas.
Bugfixes
* ssh(1), sshd(8): add compatibility workarounds for FuTTY
* ssh(1), sshd(8): refine compatibility workarounds for WinSCP
* Fix a number of memory faults (double-free, free of uninitialised
memory, etc) in ssh(1) and ssh-keygen(1). Reported by Mateusz
Kocielski.
Checksums:
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available as RELEASE_KEY.asc from
the mirror sites.
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
OpenSSH 7.0 was released on 2015-08-11. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support. OpenSSH also includes
transitional support for the legacy SSH 1.3 and 1.5 protocols
that may be enabled at compile-time.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
http://www.openssh.com/donations.html
Future deprecation notice
We plan on retiring more legacy cryptography in the next release
including:
* Refusing all RSA keys smaller than 1024 bits (the current minimum
is 768 bits)
* Several ciphers will be disabled by default: blowfish-cbc,
cast128-cbc, all arcfour variants and the rijndael-cbc aliases
for AES.
* MD5-based HMAC algorithms will be disabled by default.
This list reflects our current intentions, but please check the final
release notes for OpenSSH 7.1 when it is released.
Changes since OpenSSH 6.9
This focus of this release is primarily to deprecate weak, legacy
and/or unsafe cryptography.
Security
* sshd(8): OpenSSH 6.8 and 6.9 incorrectly set TTYs to be world-
writable. Local attackers may be able to write arbitrary messages
to logged-in users, including terminal escape sequences.
Reported by Nikolay Edigaryev.
* sshd(8): Portable OpenSSH only: Fixed a privilege separation
weakness related to PAM support. Attackers who could successfully
compromise the pre-authentication process for remote code
execution and who had valid credentials on the host could
impersonate other users. Reported by Moritz Jodeit.
* sshd(8): Portable OpenSSH only: Fixed a use-after-free bug
related to PAM support that was reachable by attackers who could
compromise the pre-authentication process for remote code
execution. Also reported by Moritz Jodeit.
* sshd(8): fix circumvention of MaxAuthTries using keyboard-
interactive authentication. By specifying a long, repeating
keyboard-interactive "devices" string, an attacker could request
the same authentication method be tried thousands of times in
a single pass. The LoginGraceTime timeout in sshd(8) and any
authentication failure delays implemented by the authentication
mechanism itself were still applied. Found by Kingcope.
Potentially-incompatible Changes
* Support for the legacy SSH version 1 protocol is disabled by
default at compile time.
* Support for the 1024-bit diffie-hellman-group1-sha1 key exchange
is disabled by default at run-time. It may be re-enabled using
the instructions at http://www.openssh.com/legacy.html
* Support for ssh-dss, ssh-dss-cert-* host and user keys is disabled
by default at run-time. These may be re-enabled using the
instructions at http://www.openssh.com/legacy.html
* Support for the legacy v00 cert format has been removed.
* The default for the sshd_config(5) PermitRootLogin option has
changed from "yes" to "prohibit-password".
* PermitRootLogin=without-password/prohibit-password now bans all
interactive authentication methods, allowing only public-key,
hostbased and GSSAPI authentication (previously it permitted
keyboard-interactive and password-less authentication if those
were enabled).
New Features
* ssh_config(5): add PubkeyAcceptedKeyTypes option to control which
public key types are available for user authentication.
* sshd_config(5): add HostKeyAlgorithms option to control which
public key types are offered for host authentications.
* ssh(1), sshd(8): extend Ciphers, MACs, KexAlgorithms,
HostKeyAlgorithms, PubkeyAcceptedKeyTypes and HostbasedKeyTypes
options to allow appending to the default set of algorithms
instead of replacing it. Options may now be prefixed with a '+'
to append to the default, e.g. "HostKeyAlgorithms=+ssh-dss".
* sshd_config(5): PermitRootLogin now accepts an argument of
'prohibit-password' as a less-ambiguous synonym of 'without-
password'.
Bugfixes
* ssh(1), sshd(8): add compatibility workarounds for Cisco and more
PuTTY versions. bz#2424
* Fix some omissions and errors in the PROTOCOL and PROTOCOL.mux
documentation relating to Unix domain socket forwarding;
bz#2421 bz#2422
* ssh(1): Improve the ssh(1) manual page to include a better
description of Unix domain socket forwarding; bz#2423
* ssh(1), ssh-agent(1): skip uninitialised PKCS#11 slots, fixing
failures to load keys when they are present. bz#2427
* ssh(1), ssh-agent(1): do not ignore PKCS#11 hosted keys that with
empty CKA_ID; bz#2429
* sshd(8): clarify documentation for UseDNS option; bz#2045
Portable OpenSSH
* Check realpath(3) behaviour matches what sftp-server requires and
use a replacement if necessary.
Checksums:
Please note that the PGP key used to sign releases was recently rotated.
The new key has been signed by the old key to provide continuity. It is
available from the mirror sites as RELEASE_KEY.asc.
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
OpenSSH 6.9 was released on 2015-07-01. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
http://www.openssh.com/donations.html
Future Deprecation Notice
The 7.0 release of OpenSSH, due for release in late July, will
deprecate several features, some of which may affect compatibility
or existing configurations. The intended changes are as follows:
* The default for the sshd_config(5) PermitRootLogin option will
change from "yes" to "no".
* Support for the legacy version 1.x of the SSH protocol will be
disabled at compile time by default.
* Support for the 1024-bit diffie-hellman-group1-sha1 key exchange
will be run-time disabled by default.
* Support for ssh-dss, ssh-dss-cert-* host and user keys will be
run-time disabled by default.
* Support for the legacy v00 cert format will be removed
* Several ciphers will be disabled by default: blowfish-cbc,
cast128-cbc, all arcfour variants and the rijndael-cbc aliases
for AES
* Refusing all RSA keys smaller than 1024 bits (the current minimum
is 768 bits)
This list reflects our current intentions, but please check the final
release notes for OpenSSH 7.0 when it is released.
Changes since OpenSSH 6.8
This is primarily a bugfix release.
Security
* ssh(1): when forwarding X11 connections with ForwardX11Trusted=no,
connections made after ForwardX11Timeout expired could be permitted
and no longer subject to XSECURITY restrictions because of an
ineffective timeout check in ssh(1) coupled with "fail open"
behaviour in the X11 server when clients attempted connections with
expired credentials. This problem was reported by Jann Horn.
* ssh-agent(1): fix weakness of agent locking (ssh-add -x) to
password guessing by implementing an increasing failure delay,
storing a salted hash of the password rather than the password
itself and using a timing-safe comparison function for verifying
unlock attempts. This problem was reported by Ryan Castellucci.
New Features
* ssh(1), sshd(8): promote chacha20-poly1305@openssh.com to be the
default cipher
* sshd(8): support admin-specified arguments to AuthorizedKeysCommand;
bz#2081
* sshd(8): add AuthorizedPrincipalsCommand that allows retrieving
authorized principals information from a subprocess rather than
a file.
* ssh(1), ssh-add(1): support PKCS#11 devices with external PIN
entry devices bz#2240
* sshd(8): allow GSSAPI host credential check to be relaxed for
multihomed hosts via GSSAPIStrictAcceptorCheck option; bz#928
* ssh-keygen(1): support "ssh-keygen -lF hostname" to search
known_hosts and print key hashes rather than full keys.
* ssh-agent(1): add -D flag to leave ssh-agent in foreground without
enabling debug mode; bz#2381
Bugfixes
* ssh(1), sshd(8): deprecate legacy SSH2_MSG_KEX_DH_GEX_REQUEST_OLD
message and do not try to use it against some 3rd-party SSH
implementations that use it (older PuTTY, WinSCP).
* Many fixes for problems caused by compile-time deactivation of
SSH1 support (including bz#2369)
* ssh(1), sshd(8): cap DH-GEX group size at 4Kbits for Cisco
implementations as some would fail when attempting to use group
sizes >4K; bz#2209
* ssh(1): fix out-of-bound read in EscapeChar configuration option
parsing; bz#2396
* sshd(8): fix application of PermitTunnel, LoginGraceTime,
AuthenticationMethods and StreamLocalBindMask options in Match
blocks
* ssh(1), sshd(8): improve disconnection message on TCP reset;
bz#2257
* ssh(1): remove failed remote forwards established by muliplexing
from the list of active forwards; bz#2363
* sshd(8): make parsing of authorized_keys "environment=" options
independent of PermitUserEnv being enabled; bz#2329
* sshd(8): fix post-auth crash with permitopen=none; bz#2355
* ssh(1), ssh-add(1), ssh-keygen(1): allow new-format private keys
to be encrypted with AEAD ciphers; bz#2366
* ssh(1): allow ListenAddress, Port and AddressFamily configuration
options to appear in any order; bz#86
* sshd(8): check for and reject missing arguments for VersionAddendum
and ForceCommand; bz#2281
* ssh(1), sshd(8): don't treat unknown certificate extensions as
fatal; bz#2387
* ssh-keygen(1): make stdout and stderr output consistent; bz#2325
* ssh(1): mention missing DISPLAY environment in debug log when X11
forwarding requested; bz#1682
* sshd(8): correctly record login when UseLogin is set; bz#378
* sshd(8): Add some missing options to sshd -T output and fix output
of VersionAddendum and HostCertificate. bz#2346
* Document and improve consistency of options that accept a "none"
argument" TrustedUserCAKeys, RevokedKeys (bz#2382),
AuthorizedPrincipalsFile (bz#2288)
* ssh(1): include remote username in debug output; bz#2368
* sshd(8): avoid compatibility problem with some versions of Tera
Term, which would crash when they received the hostkeys notification
message (hostkeys-00@openssh.com)
* sshd(8): mention ssh-keygen -E as useful when comparing legacy MD5
host key fingerprints; bz#2332
* ssh(1): clarify pseudo-terminal request behaviour and use make
manual language consistent; bz#1716
* ssh(1): document that the TERM environment variable is not subject
to SendEnv and AcceptEnv; bz#2386
Portable OpenSSH
* sshd(8): Format UsePAM setting when using sshd -T, part of bz#2346
* Look for '${host}-ar' before 'ar', making cross-compilation easier;
bz#2352.
* Several portable compilation fixes: bz#2402, bz#2337, bz#2370
* moduli(5): update DH-GEX moduli
Checksums:
Please note that the PGP key used to sign releases was recently rotated.
The new key has been signed by the old key to provide continuity. It is
available from the mirror sites as RELEASE_KEY.asc.
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
OpenSSH 6.8 was released on 2015-03-18. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
http://www.openssh.com/donations.html
Changes since OpenSSH 6.7
This is a major release, containing a number of new features as
well as a large internal re-factoring.
Potentially-incompatible changes
* sshd(8): UseDNS now defaults to 'no'. Configurations that match
against the client host name (via sshd_config or authorized_keys)
may need to re-enable it or convert to matching against addresses.
New Features
* Much of OpenSSH's internal code has been re-factored to be more
library-like. These changes are mostly not user-visible, but
have greatly improved OpenSSH's testability and internal layout.
* Add FingerprintHash option to ssh(1) and sshd(8), and equivalent
command-line flags to the other tools to control algorithm used
for key fingerprints. The default changes from MD5 to SHA256 and
format from hex to base64.
Fingerprints now have the hash algorithm prepended. An example of
the new format: SHA256:mVPwvezndPv/ARoIadVY98vAC0g+P/5633yTC4d/wXE
Please note that visual host keys will also be different.
* ssh(1), sshd(8): Experimental host key rotation support. Add a
protocol extension for a server to inform a client of all its
available host keys after authentication has completed. The client
may record the keys in known_hosts, allowing it to upgrade to better
host key algorithms and a server to gracefully rotate its keys.
The client side of this is controlled by a UpdateHostkeys config
option (default off).
* ssh(1): Add a ssh_config HostbasedKeyType option to control which
host public key types are tried during host-based authentication.
* ssh(1), sshd(8): fix connection-killing host key mismatch errors
when sshd offers multiple ECDSA keys of different lengths.
* ssh(1): when host name canonicalisation is enabled, try to
parse host names as addresses before looking them up for
canonicalisation. fixes bz#2074 and avoiding needless DNS
lookups in some cases.
* ssh-keygen(1), sshd(8): Key Revocation Lists (KRLs) no longer
require OpenSSH to be compiled with OpenSSL support.
* ssh(1), ssh-keysign(8): Make ed25519 keys work for host based
authentication.
* sshd(8): SSH protocol v.1 workaround for the Meyer, et al,
Bleichenbacher Side Channel Attack. Fake up a bignum key before
RSA decryption.
* sshd(8): Remember which public keys have been used for
authentication and refuse to accept previously-used keys.
This allows AuthenticationMethods=publickey,publickey to require
that users authenticate using two _different_ public keys.
* sshd(8): add sshd_config HostbasedAcceptedKeyTypes and
PubkeyAcceptedKeyTypes options to allow sshd to control what
public key types will be accepted. Currently defaults to all.
* sshd(8): Don't count partial authentication success as a failure
against MaxAuthTries.
* ssh(1): Add RevokedHostKeys option for the client to allow
text-file or KRL-based revocation of host keys.
* ssh-keygen(1), sshd(8): Permit KRLs that revoke certificates by
serial number or key ID without scoping to a particular CA.
* ssh(1): Add a "Match canonical" criteria that allows ssh_config
Match blocks to trigger only in the second config pass.
* ssh(1): Add a -G option to ssh that causes it to parse its
configuration and dump the result to stdout, similar to "sshd -T".
* ssh(1): Allow Match criteria to be negated. E.g. "Match !host".
* The regression test suite has been extended to cover more OpenSSH
features. The unit tests have been expanded and now cover key
exchange.
Bugfixes
* ssh-keyscan(1): ssh-keyscan has been made much more robust again
servers that hang or violate the SSH protocol.
* ssh(1), ssh-keygen(1): Fix regression bz#2306: Key path names were
being lost as comment fields.
* ssh(1): Allow ssh_config Port options set in the second config
parse phase to be applied (they were being ignored). bz#2286
* ssh(1): Tweak config re-parsing with host canonicalisation - make
the second pass through the config files always run when host name
canonicalisation is enabled (and not whenever the host name
changes) bz#2267
* ssh(1): Fix passing of wildcard forward bind addresses when
connection multiplexing is in use; bz#2324;
* ssh-keygen(1): Fix broken private key conversion from non-OpenSSH
formats; bz#2345.
* ssh-keygen(1): Fix KRL generation bug when multiple CAs are in
use.
* Various fixes to manual pages: bz#2288, bz#2316, bz#2273
Portable OpenSSH
* Support --without-openssl at configure time
Disables and removes dependency on OpenSSL. Many features,
including SSH protocol 1 are not supported and the set of crypto
options is greatly restricted. This will only work on systems
with native arc4random or /dev/urandom.
Considered highly experimental for now.
* Support --without-ssh1 option at configure time
Allows disabling support for SSH protocol 1.
* sshd(8): Fix compilation on systems with IPv6 support in utmpx; bz#2296
* Allow custom service name for sshd on Cygwin. Permits the use of
multiple sshd running with different service names.
Checksums:
Please note that the PGP key used to sign releases was recently rotated.
The new key has been signed by the old key to provide continuity. It is
available from the mirror sites as RELEASE_KEY.asc.
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
OpenSSH 6.7 was released on 2014-10-06. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
http://www.openssh.com/donations.html
Changes since OpenSSH 6.6
Potentially-incompatible changes
* sshd(8): The default set of ciphers and MACs has been altered to
remove unsafe algorithms. In particular, CBC ciphers and arcfour*
are disabled by default.
The full set of algorithms remains available if configured
explicitly via the Ciphers and MACs sshd_config options.
* sshd(8): Support for tcpwrappers/libwrap has been removed.
* OpenSSH 6.5 and 6.6 have a bug that causes ~0.2% of connections
using the curve25519-sha256@libssh.org KEX exchange method to fail
when connecting with something that implements the specification
correctly. OpenSSH 6.7 disables this KEX method when speaking to
one of the affected versions.
New Features
* Major internal refactoring to begin to make part of OpenSSH usable
as a library. So far the wire parsing, key handling and KRL code
has been refactored. Please note that we do not consider the API
stable yet, nor do we offer the library in separable form.
* ssh(1), sshd(8): Add support for Unix domain socket forwarding.
A remote TCP port may be forwarded to a local Unix domain socket
and vice versa or both ends may be a Unix domain socket.
* ssh(1), ssh-keygen(1): Add support for SSHFP DNS records for
ED25519 key types.
* sftp(1): Allow resumption of interrupted uploads.
* ssh(1): When rekeying, skip file/DNS lookups of the hostkey if it
is the same as the one sent during initial key exchange; bz#2154
* sshd(8): Allow explicit ::1 and 127.0.0.1 forwarding bind
addresses when GatewayPorts=no; allows client to choose address
family; bz#2222
* sshd(8): Add a sshd_config PermitUserRC option to control whether
~/.ssh/rc is executed, mirroring the no-user-rc authorized_keys
option; bz#2160
* ssh(1): Add a %C escape sequence for LocalCommand and ControlPath
that expands to a unique identifier based on a hash of the tuple of
(local host, remote user, hostname, port). Helps avoid exceeding
miserly pathname limits for Unix domain sockets in multiplexing
control paths; bz#2220
* sshd(8): Make the "Too many authentication failures" message
include the user, source address, port and protocol in a format
similar to the authentication success / failure messages; bz#2199
* Added unit and fuzz tests for refactored code. These are run
automatically in portable OpenSSH via the "make tests" target.
Bugfixes
* sshd(8): Fix remote forwarding with the same listen port but
different listen address.
* ssh(1): Fix inverted test that caused PKCS#11 keys that were
explicitly listed in ssh_config or on the commandline not to be
preferred.
* ssh-keygen(1): Fix bug in KRL generation: multiple consecutive
revoked certificate serial number ranges could be serialised to an
invalid format. Readers of a broken KRL caused by this bug will
fail closed, so no should-have-been-revoked key will be accepted.
* ssh(1): Reflect stdio-forward ("ssh -W host:port ...") failures in
exit status. Previously we were always returning 0; bz#2255
* ssh(1), ssh-keygen(1): Make Ed25519 keys' title fit properly in the
randomart border; bz#2247
* ssh-agent(1): Only cleanup agent socket in the main agent process
and not in any subprocesses it may have started (e.g. forked
askpass). Fixes agent sockets being zapped when askpass processes
fatal(); bz#2236
* ssh-add(1): Make stdout line-buffered; saves partial output getting
lost when ssh-add fatal()s part-way through (e.g. when listing keys
from an agent that supports key types that ssh-add doesn't);
bz#2234
* ssh-keygen(1): When hashing or removing hosts, don't choke on
@revoked markers and don't remove @cert-authority markers; bz#2241
* ssh(1): Don't fatal when hostname canonicalisation fails and a
ProxyCommand is in use; continue and allow the ProxyCommand to
connect anyway (e.g. to a host with a name outside the DNS behind
a bastion)
* scp(1): When copying local->remote fails during read, don't send
uninitialised heap to the remote end.
* sftp(1): Fix fatal "el_insertstr failed" errors when tab-completing
filenames with a single quote char somewhere in the string;
bz#2238
* ssh-keyscan(1): Scan for Ed25519 keys by default.
* ssh(1): When using VerifyHostKeyDNS with a DNSSEC resolver, down-
convert any certificate keys to plain keys and attempt SSHFP
resolution. Prevents a server from skipping SSHFP lookup and
forcing a new-hostkey dialog by offering only certificate keys.
* sshd(8): Avoid crash at exit via NULL pointer reference; bz#2225
* Fix some strict-alignment errors.
Portable OpenSSH
* Portable OpenSSH now supports building against libressl-portable.
* Portable OpenSSH now requires openssl 0.9.8f or greater. Older
versions are no longer supported.
* In the OpenSSL version check, allow fix version upgrades (but not
downgrades. Debian bug #748150.
* sshd(8): On Cygwin, determine privilege separation user at runtime,
since it may need to be a domain account.
* sshd(8): Don't attempt to use vhangup on Linux. It doesn't work for
non-root users, and for them it just messes up the tty settings.
* Use CLOCK_BOOTTIME in preference to CLOCK_MONOTONIC when it is
available. It considers time spent suspended, thereby ensuring
timeouts (e.g. for expiring agent keys) fire correctly. bz#2228
* Add support for ed25519 to opensshd.init init script.
* sftp-server(8): On platforms that support it, use prctl() to
prevent sftp-server from accessing /proc/self/{mem,maps}
Checksums:
Please note that the PGP key used to sign releases was recently rotated.
The new key has been signed by the old key to provide continuity. It is
available from the mirror sites as RELEASE_KEY.asc.
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
OpenSSH 6.6 was released on 2014-03-15. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
http://www.openssh.com/donations.html
Changes since OpenSSH 6.6
This is primarily a bugfix release.
Security:
* sshd(8): when using environment passing with a sshd_config(5)
AcceptEnv pattern with a wildcard. OpenSSH prior to 6.6 could be
tricked into accepting any environment variable that contains the
characters before the wildcard character.
New / changed features:
* ssh(1), sshd(8): this release removes the J-PAKE authentication code.
This code was experimental, never enabled and had been unmaintained
for some time.
* ssh(1): when processing Match blocks, skip 'exec' clauses other clauses
predicates failed to match.
* ssh(1): if hostname canonicalisation is enabled and results in the
destination hostname being changed, then re-parse ssh_config(5) files
using the new destination hostname. This gives 'Host' and 'Match'
directives that use the expanded hostname a chance to be applied.
Bugfixes:
* ssh(1): avoid spurious "getsockname failed: Bad file descriptor" in
ssh -W. bz#2200, debian#738692
* sshd(8): allow the shutdown(2) syscall in seccomp-bpf and systrace
sandbox modes, as it is reachable if the connection is terminated
during the pre-auth phase.
* ssh(1), sshd(8): fix unsigned overflow that in SSH protocol 1 bignum
parsing. Minimum key length checks render this bug unexploitable to
compromise SSH 1 sessions.
* sshd_config(5): clarify behaviour of a keyword that appears in
multiple matching Match blocks. bz#2184
* ssh(1): avoid unnecessary hostname lookups when canonicalisation is
disabled. bz#2205
* sshd(8): avoid sandbox violation crashes in GSSAPI code by caching
the supported list of GSSAPI mechanism OIDs before entering the
sandbox. bz#2107
* ssh(1): fix possible crashes in SOCKS4 parsing caused by assumption
that the SOCKS username is nul-terminated.
* ssh(1): fix regression for UsePrivilegedPort=yes when BindAddress is
not specified.
* ssh(1), sshd(8): fix memory leak in ECDSA signature verification.
* ssh(1): fix matching of 'Host' directives in ssh_config(5) files
to be case-insensitive again (regression in 6.5).
Portable OpenSSH:
* sshd(8): don't fatal if the FreeBSD Capsicum is offered by the
system headers and libc but is not supported by the kernel.
* Fix build using the HP-UX compiler.
Checksums:
Please note that the PGP key used to sign releases was recently rotated.
The new key has been signed by the old key to provide continuity. It is
available from the mirror sites as RELEASE_KEY.asc.
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
Changes since OpenSSH 6.4
This is a feature-focused release.
New features:
* ssh(1), sshd(8): Add support for key exchange using elliptic-curve
Diffie Hellman in Daniel Bernstein's Curve25519. This key exchange
method is the default when both the client and server support it.
* ssh(1), sshd(8): Add support for Ed25519 as a public key type.
Ed25519 is a elliptic curve signature scheme that offers
better security than ECDSA and DSA and good performance. It may be
used for both user and host keys.
* Add a new private key format that uses a bcrypt KDF to better
protect keys at rest. This format is used unconditionally for
Ed25519 keys, but may be requested when generating or saving
existing keys of other types via the -o ssh-keygen(1) option.
We intend to make the new format the default in the near future.
Details of the new format are in the PROTOCOL.key file.
* ssh(1), sshd(8): Add a new transport cipher
"chacha20-poly1305@openssh.com" that combines Daniel Bernstein's
ChaCha20 stream cipher and Poly1305 MAC to build an authenticated
encryption mode. Details are in the PROTOCOL.chacha20poly1305 file.
* ssh(1), sshd(8): Refuse RSA keys from old proprietary clients and
servers that use the obsolete RSA+MD5 signature scheme. It will
still be possible to connect with these clients/servers but only
DSA keys will be accepted, and OpenSSH will refuse connection
entirely in a future release.
* ssh(1), sshd(8): Refuse old proprietary clients and servers that
use a weaker key exchange hash calculation.
* ssh(1): Increase the size of the Diffie-Hellman groups requested
for each symmetric key size. New values from NIST Special
Publication 800-57 with the upper limit specified by RFC4419.
* ssh(1), ssh-agent(1): Support PKCS#11 tokens that only provide
X.509 certs instead of raw public keys (requested as bz#1908).
* ssh(1): Add a ssh_config(5) "Match" keyword that allows
conditional configuration to be applied by matching on hostname,
user and result of arbitrary commands.
* ssh(1): Add support for client-side hostname canonicalisation
using a set of DNS suffixes and rules in ssh_config(5). This
allows unqualified names to be canonicalised to fully-qualified
domain names to eliminate ambiguity when looking up keys in
known_hosts or checking host certificate names.
* sftp-server(8): Add the ability to whitelist and/or blacklist sftp
protocol requests by name.
* sftp-server(8): Add a sftp "fsync@openssh.com" to support calling
fsync(2) on an open file handle.
* sshd(8): Add a ssh_config(5) PermitTTY to disallow TTY allocation,
mirroring the longstanding no-pty authorized_keys option.
* ssh(1): Add a ssh_config ProxyUseFDPass option that supports the
use of ProxyCommands that establish a connection and then pass a
connected file descriptor back to ssh(1). This allows the
ProxyCommand to exit rather than staying around to transfer data.
Bugfixes:
* ssh(1), sshd(8): Fix potential stack exhaustion caused by nested
certificates.
* ssh(1): bz#1211: make BindAddress work with UsePrivilegedPort.
* sftp(1): bz#2137: fix the progress meter for resumed transfer.
* ssh-add(1): bz#2187: do not request smartcard PIN when removing
keys from ssh-agent.
* sshd(8): bz#2139: fix re-exec fallback when original sshd binary
cannot be executed.
* ssh-keygen(1): Make relative-specified certificate expiry times
relative to current time and not the validity start time.
* sshd(8): bz#2161: fix AuthorizedKeysCommand inside a Match block.
* sftp(1): bz#2129: symlinking a file would incorrectly canonicalise
the target path.
* ssh-agent(1): bz#2175: fix a use-after-free in the PKCS#11 agent
helper executable.
* sshd(8): Improve logging of sessions to include the user name,
remote host and port, the session type (shell, command, etc.) and
allocated TTY (if any).
* sshd(8): bz#1297: tell the client (via a debug message) when
their preferred listen address has been overridden by the
server's GatewayPorts setting.
* sshd(8): bz#2162: include report port in bad protocol banner
message.
* sftp(1): bz#2163: fix memory leak in error path in do_readdir().
* sftp(1): bz#2171: don't leak file descriptor on error.
* sshd(8): Include the local address and port in "Connection from
..." message (only shown at loglevel>=verbose).
Portable OpenSSH:
* Please note that this is the last version of Portable OpenSSH that
will support versions of OpenSSL prior to 0.9.6. Support (i.e.
SSH_OLD_EVP) will be removed following the 6.5p1 release.
* Portable OpenSSH will attempt compile and link as a Position
Independent Executable on Linux, OS X and OpenBSD on recent gcc-
like compilers. Other platforms and older/other compilers may
request this using the --with-pie configure flag.
* A number of other toolchain-related hardening options are used
automatically if available, including -ftrapv to abort on signed
integer overflow and options to write-protect dynamic linking
information. The use of these options may be disabled using the
--without-hardening configure flag.
* If the toolchain supports it, one of the -fstack-protector-strong,
-fstack-protector-all or -fstack-protector compilation flag are
used to add guards to mitigate attacks based on stack overflows.
The use of these options may be disabled using the
--without-stackprotect configure option.
* sshd(8): Add support for pre-authentication sandboxing using the
Capsicum API introduced in FreeBSD 10.
* Switch to a ChaCha20-based arc4random() PRNG for platforms that do
not provide their own.
* sshd(8): bz#2156: restore Linux oom_adj setting when handling
SIGHUP to maintain behaviour over restart.
* sshd(8): bz#2032: use local username in krb5_kuserok check rather
than full client name which may be of form user@REALM.
* ssh(1), sshd(8): Test for both the presence of ECC NID numbers in
OpenSSL and that they actually work. Fedora (at least) has
NID_secp521r1 that doesn't work.
* bz#2173: use pkg-config --libs to include correct -L location for
libedit.
Checksums:
Please note that the PGP key used to sign releases has been rotated.
The new key has been signed by the old key to provide continuity. It
is available from the mirror sites as RELEASE_KEY.asc.
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
Changes since OpenSSH 6.3
This release fixes a security bug:
* sshd(8): fix a memory corruption problem triggered during rekeying
when an AES-GCM cipher is selected. Full details of the vulnerability
are available at: http://www.openssh.com/txt/gcmrekey.adv
Checksums:
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
Changes since OpenSSH 6.2
This release is predominantly a bugfix release:
Features:
* sshd(8): add ssh-agent(1) support to sshd(8); allows encrypted hostkeys,
or hostkeys on smartcards.
* ssh(1)/sshd(8): allow optional time-based rekeying via a second argument
to the existing RekeyLimit option. RekeyLimit is now supported in
sshd_config as well as on the client.
* sshd(8): standardise logging of information during user authentication.
The presented key/cert and the remote username (if available) is now
logged in the authentication success/failure message on the same log
line as the local username, remote host/port and protocol in use.
Certificates contents and the key fingerprint of the signing CA are
logged too.
Including all relevant information on a single line simplifies log
analysis as it is no longer necessary to relate information scattered
across multiple log entries.
* ssh(1): add the ability to query which ciphers, MAC algorithms, key
types and key exchange methods are supported in the binary.
* ssh(1): support ProxyCommand=- to allow support cases where stdin and
stdout already point to the proxy.
* ssh(1): allow IdentityFile=none
* ssh(1)/sshd(8): add -E option to ssh and sshd to append debugging logs
to a specified file instead of stderr or syslog.
* sftp(1): add support for resuming partial downloads using the "reget"
command and on the sftp commandline or on the "get" commandline using
the "-a" (append) option.
* ssh(1): add an "IgnoreUnknown" configuration option to selectively
suppress errors arising from unknown configuration directives.
* sshd(8): add support for submethods to be appended to required
authentication methods listed via AuthenticationMethods.
Bugfixes:
* sshd(8): fix refusal to accept certificate if a key of a different type
to the CA key appeared in authorized_keys before the CA key.
* ssh(1)/ssh-agent(1)/sshd(8): Use a monotonic time source for timers so
that things like keepalives and rekeying will work properly over clock
steps.
* sftp(1): update progressmeter when data is acknowledged, not when it's
sent. bz#2108
* ssh(1)/ssh-keygen(1): improve error messages when the current user does
not exist in /etc/passwd; bz#2125
* ssh(1): reset the order in which public keys are tried after partial
authentication success.
* ssh-agent(1): clean up socket files after SIGINT when in debug mode;
bz#2120
* ssh(1) and others: avoid confusing error messages in the case of broken
system resolver configurations; bz#2122
* ssh(1): set TCP nodelay for connections started with -N; bz#2124
* ssh(1): correct manual for permission requirements on ~/.ssh/config;
bz#2078
* ssh(1): fix ControlPersist timeout not triggering in cases where TCP
connections have hung. bz#1917
* ssh(1): properly detach a ControlPersist master from its controlling
terminal.
* sftp(1): avoid crashes in libedit when it has been compiled with multi-
byte character support. bz#1990
* sshd(8): when running sshd -D, close stderr unless we have explicitly
requested logging to stderr. bz#1976,
* ssh(1): fix incomplete bzero; bz#2100
* sshd(8): log and error and exit if ChrootDirectory is specified and
running without root privileges.
* Many improvements to the regression test suite. In particular log files
are now saved from ssh and sshd after failures.
* Fix a number of memory leaks. bz#1967 bz#2096 and others
* sshd(8): fix public key authentication when a :style is appended to
the requested username.
* ssh(1): do not fatally exit when attempting to cleanup multiplexing-
created channels that are incompletely opened. bz#2079
Portable OpenSSH:
* Major overhaul of contrib/cygwin/README
* Fix unaligned accesses in umac.c for strict-alignment architectures.
bz#2101
* Enable -Wsizeof-pointer-memaccess if the compiler supports it. bz#2100
* Fix broken incorrect commandline reporting errors. bz#1448
* Only include SHA256 and ECC-based key exchange methods if libcrypto has
the required support.
* Fix crash in SOCKS5 dynamic forwarding code on strict-alignment
architectures.
* A number of portability fixes for Android:
* Don't try to use lastlog on Android; bz#2111
* Fall back to using openssl's DES_crypt function on platforms that don't
have a native crypt() function; bz#2112
* Test for fd_mask, howmany and NFDBITS rather than trying to enumerate
the platforms that don't have them. bz#2085
* Replace S_IWRITE, which isn't standardized, with S_IWUSR, which is.
bz#2085
* Add a null implementation of endgrent for platforms that don't have
it (eg Android) bz#2087
* Support platforms, such as Android, that lack struct passwd.pw_gecos.
bz#2086
Checksums:
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
Changes since OpenSSH 6.2p1
This is a bugfix release:
Bugfixes:
* ssh(1): Only warn for missing identity files that were explicitly
specified.
* Fix bug in contributed contrib/ssh-copy-id script that could result in
"rm *" being called on mktemp failure. bz#2105
* sshd(8): Quiet disconnect notifications on the server from error() back
to logit() from error() for normal, client-initiated disconnections.
bz#2057
* Avoid conflicting definitions of __int64 on Cygwin
Checksums:
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
Changes since OpenSSH 6.1
This release introduces a number of new features:
Features:
* ssh(1)/sshd(8): Added support for AES-GCM authenticated encryption in
SSH protocol 2. The new cipher is available as aes128-gcm@openssh.com
and aes256-gcm@openssh.com. It uses an identical packet format to the
AES-GCM mode specified in RFC 5647, but uses simpler and different
selection rules during key exchange.
* ssh(1)/sshd(8): Added support for encrypt-then-mac (EtM) MAC modes
for SSH protocol 2. These modes alter the packet format and compute
the MAC over the packet length and encrypted packet rather than over
the plaintext data. These modes are considered more secure and are
used by default when available.
* ssh(1)/sshd(8): Added support for the UMAC-128 MAC as
"umac-128@openssh.com" and "umac-128-etm@openssh.com". The latter
being an encrypt-then-mac mode.
* sshd(8): Added support for multiple required authentication in SSH
protocol 2 via an AuthenticationMethods option. This option lists
one or more comma-separated lists of authentication method names.
Successful completion of all the methods in any list is required for
authentication to complete. This allows, for example, requiring a
user having to authenticate via public key or GSSAPI before they
are offered password authentication.
* sshd(8)/ssh-keygen(1): Added support for Key Revocation Lists
(KRLs), a compact binary format to represent lists of revoked keys
and certificates that take as little as one bit per certificate when
revoking by serial number. KRLs may be generated using ssh-keygen(1)
and are loaded into sshd(8) via the existing RevokedKeys sshd_config
option.
* ssh(1): IdentitiesOnly now applies to keys obtained from a
PKCS11Provider. This allows control of which keys are offered from
tokens using IdentityFile.
* sshd(8): sshd_config(5)'s AllowTcpForwarding now accepts "local"
and "remote" in addition to its previous "yes"/"no" keywords to allow
the server to specify whether just local or remote TCP forwarding is
enabled.
* sshd(8): Added a sshd_config(5) option AuthorizedKeysCommand to
support fetching authorized_keys from a command in addition to (or
instead of) from the filesystem. The command is run under an account
specified by an AuthorizedKeysCommandUser sshd_config(5) option.
* sftp-server(8): Now supports a -d option to allow the starting
directory to be something other than the user's home directory.
* ssh-keygen(1): Now allows fingerprinting of keys hosted in PKCS#11
tokens using "ssh-keygen -lD pkcs11_provider".
* ssh(1): When SSH protocol 2 only is selected (the default), ssh(1)
now immediately sends its SSH protocol banner to the server without
waiting to receive the server's banner, saving time when connecting.
* ssh(1): Added ~v and ~V escape sequences to raise and lower the
logging level respectively.
* ssh(1): Made the escape command help (~?) context sensitive so that
only commands that will work in the current session are shown.
* ssh-keygen(1): When deleting host lines from known_hosts using
"ssh-keygen -R host", ssh-keygen(1) now prints details of which lines
were removed.
Bugfixes:
* ssh(1): Force a clean shutdown of ControlMaster client sessions when
the ~. escape sequence is used. This means that ~. should now work in
mux clients even if the server is no longer responding.
* ssh(1): Correctly detect errors during local TCP forward setup in
multiplexed clients. bz#2055
* ssh-add(1): Made deleting explicit keys "ssh-add -d" symmetric with
adding keys with respect to certificates. It now tries to delete the
corresponding certificate and respects the -k option to allow deleting
of the key only.
* sftp(1): Fix a number of parsing and command-editing bugs, including
bz#1956
* ssh(1): When muxmaster is run with -N, ensured that it shuts down
gracefully when a client sends it "-O stop" rather than hanging around.
bz#1985
* ssh-keygen(1): When screening moduli candidates, append to the file
rather than overwriting to allow resumption. bz#1957
* ssh(1): Record "Received disconnect" messages at ERROR rather than
INFO priority. bz#2057.
* ssh(1): Loudly warn if explicitly-provided private key is unreadable.
bz#1981
Portable OpenSSH:
* sshd(8): The Linux seccomp-filter sandbox is now supported on ARM
platforms where the kernel supports it.
* sshd(8): The seccomp-filter sandbox will not be enabled if the system
headers support it at compile time, regardless of whether it can be
enabled then. If the run-time system does not support seccomp-filter,
sshd will fall back to the rlimit pseudo-sandbox.
* ssh(1): Don't link in the Kerberos libraries. They aren't necessary
on the client, just on sshd(8). bz#2072
* Fix GSSAPI linking on Solaris, which uses a differently-named GSSAPI
library. bz#2073
* Fix compilation on systems with openssl-1.0.0-fips.
* Fix a number of errors in the RPM spec files.
Checksums:
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
OpenSSH 6.1 was released on 2012-08-29. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
http://www.openssh.com/donations.html
Changes since OpenSSH 6.0
This is primarily a bugfix release.
Features:
* sshd(8): This release turns on pre-auth sandboxing sshd by default for
new installs, by setting UsePrivilegeSeparation=sandbox in sshd_config.
* ssh-keygen(1): Add options to specify starting line number and number of
lines to process when screening moduli candidates, allowing processing
of different parts of a candidate moduli file in parallel
* sshd(8): The Match directive now supports matching on the local (listen)
address and port upon which the incoming connection was received via
LocalAddress and LocalPort clauses.
* sshd(8): Extend sshd_config Match directive to allow setting AcceptEnv
and {Allow,Deny}{Users,Groups}
* Add support for RFC6594 SSHFP DNS records for ECDSA key types. bz#1978
* ssh-keygen(1): Allow conversion of RSA1 keys to public PEM and PKCS8
* sshd(8): Allow the sshd_config PermitOpen directive to accept "none" as
an argument to refuse all port-forwarding requests.
* sshd(8): Support "none" as an argument for AuthorizedPrincipalsFile
* ssh-keyscan(1): Look for ECDSA keys by default. bz#1971
* sshd(8): Add "VersionAddendum" to sshd_config to allow server operators
to append some arbitrary text to the server SSH protocol banner.
Bugfixes:
* ssh(1)/sshd(8): Don't spin in accept() in situations of file
descriptor exhaustion. Instead back off for a while.
* ssh(1)/sshd(8): Remove hmac-sha2-256-96 and hmac-sha2-512-96 MACs as
they were removed from the specification. bz#2023,
* sshd(8): Handle long comments in config files better. bz#2025
* ssh(1): Delay setting tty_flag so RequestTTY options are correctly
picked up. bz#1995
* sshd(8): Fix handling of /etc/nologin incorrectly being applied to root
on platforms that use login_cap.
Portable OpenSSH:
* sshd(8): Allow sshd pre-auth sandboxing to fall-back to the rlimit
sandbox from the Linux SECCOMP filter sandbox when the latter is
not available in the kernel.
* ssh(1): Fix NULL dereference when built with LDNS and using DNSSEC to
retrieve a CNAME SSHFP record.
* Fix cross-compilation problems related to pkg-config. bz#1996
Checksums:
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
OpenSSH 6.0 was released on 2012-04-22. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
http://www.openssh.com/donations.html
Changes since OpenSSH 5.9
This is primarily a bugfix release.
Features:
* ssh-keygen(1): Add optional checkpoints for moduli screening
* ssh-add(1): new -k option to load plain keys (skipping certificates)
* sshd(8): Add wildcard support to PermitOpen, allowing things like
"PermitOpen localhost:*". bz #1857
* ssh(1): support for cancelling local and remote port forwards via the
multiplex socket. Use ssh -O cancel -L xx:xx:xx -R yy:yy:yy user@host"
to request the cancellation of the specified forwardings
* support cancellation of local/dynamic forwardings from ~C commandline
Bugfixes:
* ssh(1): ensure that $DISPLAY contains only valid characters before
using it to extract xauth data so that it can't be used to play local
shell metacharacter games.
* ssh(1): unbreak remote portforwarding with dynamic allocated listen ports
* scp(1): uppress adding '--' to remote commandlines when the first
argument does not start with '-'. saves breakage on some
difficult-to-upgrade embedded/router platforms
* ssh(1)/sshd(8): fix typo in IPQoS parsing: there is no "AF14" class,
but there is an "AF21" class
* ssh(1)/sshd(8): do not permit SSH2_MSG_SERVICE_REQUEST/ACCEPT during
rekeying
* ssh(1): skip attempting to create ~/.ssh when -F is passed
* sshd(8): unbreak stdio forwarding when ControlPersist is in use; bz#1943
* sshd(1): send tty break to pty master instead of (probably already
closed) slave side; bz#1859
* sftp(1): silence error spam for "ls */foo" in directory with files;
bz#1683
* Fixed a number of memory and file descriptor leaks
Portable OpenSSH:
* Add a new privilege separation sandbox implementation for Linux's
new seccomp sandbox, automatically enabled on platforms that support
it. (Note: privilege separation sandboxing is still experimental)
* Fix compilation problems on FreeBSD, where libutil contained openpty()
but not login().
* ssh-keygen(1): don't fail in -A on platforms that don't support ECC
* Add optional support for LDNS, a BSD licensed DNS resolver library
which supports DNSSEC
* Relax OpenSSL version check to allow running OpenSSH binaries on
systems with OpenSSL libraries with a newer "fix" or "patch" level
than the binaries were originally compiled on (previous check only
allowed movement within "patch" releases). bz#1991
* Fix builds using contributed Redhat spec file. bz#1992
Checksums:
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
OpenSSH 5.9 was released on 2011-09-06. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
http://www.openssh.com/donations.html
Changes since OpenSSH 5.8
Features:
* Introduce sandboxing of the pre-auth privsep child using an optional
sshd_config(5) "UsePrivilegeSeparation=sandbox" mode that enables
mandatory restrictions on the syscalls the privsep child can perform.
This intention is to prevent a compromised privsep child from being
used to attack other hosts (by opening sockets and proxying) or
probing local kernel attack surface.
Three concrete sandbox implementation are provided (selected at
configure time): systrace, seatbelt and rlimit.
The systrace sandbox uses systrace(4) in unsupervised "fast-path"
mode, where a list of permitted syscalls is supplied. Any syscall not
on the list results in SIGKILL being sent to the privsep child. Note
that this requires a kernel with the new SYSTR_POLICY_KILL option
(only OpenBSD has this mode at present).
The seatbelt sandbox uses OS X/Darwin sandbox(7) facilities with a
strict (kSBXProfilePureComputation) policy that disables access to
filesystem and network resources.
The rlimit sandbox is a fallback choice for platforms that don't
support a better one; it uses setrlimit() to reset the hard-limit
of file descriptors and processes to zero, which should prevent
the privsep child from forking or opening new network connections.
Sandboxing of the privilege separated child process is currently
experimental but should become the default in a future release.
Native sandboxes for other platforms are welcome (e.g. Capsicum,
Linux pid/net namespaces, etc.)
* Add new SHA256-based HMAC transport integrity modes from
http://www.ietf.org/id/draft-dbider-sha2-mac-for-ssh-02.txt
These modes are hmac-sha2-256, hmac-sha2-256-96, hmac-sha2-512,
and hmac-sha2-512-96, and are available by default in ssh(1) and
sshd(8)
* The pre-authentication sshd(8) privilege separation slave process
now logs via a socket shared with the master process, avoiding the
need to maintain /dev/log inside the chroot.
* ssh(1) now warns when a server refuses X11 forwarding
* sshd_config(5)'s AuthorizedKeysFile now accepts multiple paths,
separated by whitespace. The undocumented AuthorizedKeysFile2
option is deprecated (though the default for AuthorizedKeysFile
includes .ssh/authorized_keys2)
* sshd_config(5): similarly deprecate UserKnownHostsFile2 and
GlobalKnownHostsFile2 by making UserKnownHostsFile and
GlobalKnownHostsFile accept multiple options and default to
include known_hosts2
* Retain key comments when loading v.2 keys. These will be visible
in "ssh-add -l" and other places. bz#439
* ssh(1) and sshd(8): set IPv6 traffic class from IPQoS (as well as
IPv4 ToS/DSCP). bz#1855
* ssh_config(5)'s ControlPath option now expands %L to the host
portion of the destination host name.
* ssh_config(5) "Host" options now support negated Host matching, e.g.
Host \*.example.org !c.example.org
User mekmitasdigoat
Will match "a.example.org", "b.example.org", but not "c.example.org"
* ssh_config(5): a new RequestTTY option provides control over when a
TTY is requested for a connection, similar to the existing -t/-tt/-T
ssh(1) commandline options.
* sshd(8): allow GSSAPI authentication to detect when a server-side
failure causes authentication failure and don't count such failures
against MaxAuthTries; bz#1244
* ssh-keygen(1): Add -A option. For each of the key types (rsa1, rsa,
dsa and ecdsa) for which host keys do not exist, generate the host
keys with the default key file path, an empty passphrase, default
bits for the key type, and default comment. This is useful for
system initialisation scripts.
* ssh(1): Allow graceful shutdown of multiplexing: request that a mux
server removes its listener socket and refuse future multiplexing
requests but don't kill existing connections. This may be requested
using "ssh -O stop ..."
* ssh-add(1) now accepts keys piped from standard input. E.g.
"ssh-add - < /path/to/key"
* ssh-keysign(8) now signs hostbased authentication
challenges correctly using ECDSA keys; bz#1858
* sftp(1): document that sftp accepts square brackets to delimit
addresses (useful for IPv6); bz#1847a
* ssh(1): when using session multiplexing, the master process will
change its process title to reflect the control path in use and
when a ControlPersist-ed master is waiting to close; bz#1883 and
bz#1911
* Other minor bugs fixed: 1849 1861 1862 1869 1875 1878 1879 1892
1900 1905 1913
Portable OpenSSH Bugfixes:
* Fix a compilation error in the SELinux support code. bz#1851
* This release removes support for ssh-rand-helper. OpenSSH now
obtains its random numbers directly from OpenSSL or from
a PRNGd/EGD instance specified at configure time.
* sshd(8) now resets the SELinux process execution context before
executing passwd for password changes; bz#1891
* Since gcc >= 4.x ignores all -Wno-options options, test only the
corresponding -W-option when trying to determine whether it is
accepted; bz#1901
* Add ECDSA key generation to the Cygwin ssh-{host,user}-config
scripts.
* Updated .spec and init files for Linux; bz#1920
* Improved SELinux error messages in context change failures and
suppress error messages when attempting to change from the
"unconfined_t" type; bz#1924 bz#1919
* Fix build errors on platforms without dlopen(); bz#1929
Checksums:
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
Portable OpenSSH 5.8p2 was released on 2011-05-03. It will be available
from the mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
http://www.openssh.com/donations.html
Changes since OpenSSH 5.8p1
Security:
* Fix local private host key compromise on platforms without host-
level randomness support (e.g. /dev/random) reported by Tomas Mraz
On hosts that did not have a randomness source configured in
OpenSSL and were not configured to use EGD/PRNGd (using the
--with-prngd-socket configure option), the ssh-rand-helper command
was being implicitly executed by ssh-keysign with open file
descriptors to the host private keys. An attacker could use
ptrace(2) to attach to ssh-rand-helper and exfiltrate the keys.
Most modern operating systems are not vulnerable. In particular,
*BSD, Linux, OS X and Cygwin do not use ssh-rand-helper.
A full advisory for this issue is available at:
http://www.openssh.com/txt/portable-keysign-rand-helper.adv
Portable OpenSSH Bugfixes:
* Fix compilation failure when enabling SELinux support.
* Revised Cygwin ssh-{host,user}-config that include ECDSA key
support.
* Revised Cygwin ssh-host-config to be more thorough in error checking
and reporting.
Checksums:
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
OpenSSH 5.8 was released on 2011-02-04. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
http://www.openssh.com/donations.html
Changes since OpenSSH 5.7
Security:
* Fix vulnerability in legacy certificate signing introduced in
OpenSSH-5.6 and found by Mateusz Kocielski.
Legacy certificates signed by OpenSSH 5.6 or 5.7 included data from
the stack in place of a random nonce field. The contents of the stack
do not appear to contain private data at this point, but this cannot
be stated with certainty for all platform, library and compiler
combinations. In particular, there exists a risk that some bytes from
the privileged CA key may be accidentally included.
A full advisory for this issue is available at:
http://www.openssh.com/txt/legacy-cert.adv
Portable OpenSSH Bugfixes:
* Fix compilation failure when enabling SELinux support.
* Do not attempt to call SELinux functions when SELinux is disabled.
bz#1851
Checksums:
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
OpenSSH 5.7 was released on 2011-01-24. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
http://www.openssh.com/donations.html
Changes since OpenSSH 5.6
Features:
* Implement Elliptic Curve Cryptography modes for key exchange (ECDH)
and host/user keys (ECDSA) as specified by RFC5656. ECDH and ECDSA
offer better performance than plain DH and DSA at the same equivalent
symmetric key length, as well as much shorter keys.
Only the mandatory sections of RFC5656 are implemented, specifically
the three REQUIRED curves nistp256, nistp384 and nistp521 and only
ECDH and ECDSA. Point compression (optional in RFC5656) is NOT
implemented.
Certificate host and user keys using the new ECDSA key types are
supported - an ECDSA key may be certified, and an ECDSA key may act
as a CA to sign certificates.
ECDH in a 256 bit curve field is the preferred key agreement
algorithm when both the client and server support it. ECDSA host
keys are preferred when learning a host's keys for the first time,
or can be learned using ssh-keyscan(1).
* sftp(1)/sftp-server(8): add a protocol extension to support a hard
link operation. It is available through the "ln" command in the
client. The old "ln" behaviour of creating a symlink is available
using its "-s" option or through the preexisting "symlink" command
* scp(1): Add a new -3 option to scp: Copies between two remote hosts
are transferred through the local host. Without this option the
data is copied directly between the two remote hosts.
* ssh(1): automatically order the hostkeys requested by the client
based on which hostkeys are already recorded in known_hosts. This
avoids hostkey warnings when connecting to servers with new ECDSA
keys, since these are now preferred when learning hostkeys for the
first time.
* ssh(1)/sshd(8): add a new IPQoS option to specify arbitrary
TOS/DSCP/QoS values instead of hardcoding lowdelay/throughput.
bz#1733
* sftp(1): the sftp client is now significantly faster at performing
directory listings, using OpenBSD glob(3) extensions to preserve
the results of stat(3) operations performed in the course of its
execution rather than performing expensive round trips to fetch
them again afterwards.
* ssh(1): "atomically" create the listening mux socket by binding it on
a temporary name and then linking it into position after listen() has
succeeded. This allows the mux clients to determine that the server
socket is either ready or stale without races. stale server sockets
are now automatically removed. (also fixes bz#1711)
* ssh(1)/sshd(8): add a KexAlgorithms knob to the client and server
configuration to allow selection of which key exchange methods are
used by ssh(1) and sshd(8) and their order of preference.
* sftp(1)/scp(1): factor out bandwidth limiting code from scp(1) into
a generic bandwidth limiter that can be attached using the atomicio
callback mechanism and use it to add a bandwidth limit option to
sftp(1). bz#1147
BugFixes:
* ssh(1)/ssh-agent(1): honour $TMPDIR for client xauth and ssh-agent
temporary directories. bz#1809
* ssh(1): avoid NULL deref on receiving a channel request on an unknown
or invalid channel; bz#1842
* sshd(8): remove a debug() that pollutes stderr on client connecting
to a server in debug mode; bz#1719
* scp(1): pass through ssh command-line flags and options when doing
remote-remote transfers, e.g. to enable agent forwarding which is
particularly useful in this case; bz#1837
* sftp-server(8): umask should be parsed as octal
* sftp(1): escape '[' in filename tab-completion
* ssh(1): Typo in confirmation message. bz#1827
* sshd(8): prevent free() of string in .rodata when overriding
AuthorizedKeys in a Match block
* sshd(8): Use default shell /bin/sh if $SHELL is ""
* ssh(1): kill proxy command on fatal() (we already killed it on
clean exit);
* ssh(1): install a SIGCHLD handler to reap expired child process;
bz#1812
* Support building against openssl-1.0.0a
Portable OpenSSH Bugfixes:
* Use mandoc as preferred manpage formatter if it is present, followed
by nroff and groff respectively.
* sshd(8): Relax permission requirement on btmp logs to allow group
read/write
* bz#1840: fix warning when configuring --with-ssl-engine
* sshd(8): Use correct uid_t/pid_t types instead of int. bz#1817
* sshd(8): bz#1824: Add Solaris Project support.
* sshd(8): Check is_selinux_enabled for exact return code since it can
apparently return -1 under some conditions.
Checksums:
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
OpenSSH 5.6 was released on 2010-08-23. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
http://www.openssh.com/donations.html
Changes since OpenSSH 5.5
Features:
* Added a ControlPersist option to ssh_config(5) that automatically
starts a background ssh(1) multiplex master when connecting. This
connection can stay alive indefinitely, or can be set to
automatically close after a user-specified duration of inactivity.
* Hostbased authentication may now use certificate host keys. CA keys
must be specified in a known_hosts file using the @cert-authority
marker as described in sshd(8).
* ssh-keygen(1) now supports signing certificate using a CA key that
has been stored in a PKCS#11 token.
* ssh(1) will now log the hostname and address that we connected to at
LogLevel=verbose after authentication is successful to mitigate
"phishing" attacks by servers with trusted keys that accept
authentication silently and automatically before presenting fake
password/passphrase prompts.
Note that, for such an attack to be successful, the user must have
disabled StrictHostKeyChecking (enabled by default) or an attacker
must have access to a trusted host key for the destination server.
* Expand %h to the hostname in ssh_config Hostname options. While this
sounds useless, it is actually handy for working with unqualified
hostnames:
Host \*.\*
Hostname %h
Host \*
Hostname %h.example.org
* Allow ssh-keygen(1) to import (-i) and export (-e) of PEM and PKCS#8
keys in addition to RFC4716 (SSH.COM) encodings via a new -m option
(bz#1749)
* sshd(8) will now queue debug messages for bad ownership or
permissions on the user's keyfiles encountered during authentication
and will send them after authentication has successfully completed.
These messages may be viewed in ssh(1) at LogLevel=debug or higher.
* ssh(1) connection multiplexing now supports remote forwarding with
dynamic port allocation and can report the allocated port back to
the user:
LPORT=\`ssh -S muxsocket -R0:localhost:25 -O forward somehost\`
* sshd(8) now supports indirection in matching of principal names
listed in certificates. By default, if a certificate has an
embedded principals list then the username on the server must match
one of the names in the list for it to be accepted for
authentication.
sshd(8) now has a new AuthorizedPrincipalsFile option to specify a
file containing a list of names that may be accepted in place of the
username when authorizing a certificate trusted via the
sshd_config(5) TrustedCAKeys option. Similarly, authentication
using a CA trusted in ~/.ssh/authorized_keys now accepts a
principals="name1[,name2,...]" to specify a list of permitted names.
If either option is absent, the current behaviour of requiring the
username to appear in principals continues to apply. These options
are useful for role accounts, disjoint account namespaces and
"user@realm"-style naming policies in certificates.
* Additional sshd_config(5) options are now valid inside Match blocks:
AuthorizedKeysFile
AuthorizedPrincipalsFile
HostbasedUsesNameFromPacketOnly
PermitTunnel
* Revised the format of certificate keys. The new format, identified as
ssh-{dss,rsa}-cert-v01@openssh.com includes the following changes:
- Adding a serial number field. This may be specified by the CA at
the time of certificate signing.
- Moving the nonce field to the beginning of the certificate where
it can better protect against chosen-prefix attacks on the
signature hash (currently infeasible against the SHA1 hash used)
- Renaming the "constraints" field to "critical options"
- Addng a new non-critical "extensions" field. The "permit-\*"
options are now extensions, rather than critical options to
permit non-OpenSSH implementation of this key format to degrade
gracefully when encountering keys with options they do not
recognize.
The older format is still supported for authentication and may still
be used when signing certificates (use "ssh-keygen -t v00 ...").
The v00 format, introduced in OpenSSH 5.4, will be supported for at
least one year from this release, after which it will be deprecated
and removed.
BugFixes:
* The PKCS#11 code now retries a lookup for a private key if there is
no matching key with CKA_SIGN attribute enabled; this fixes
MuscleCard support (bz#1736)
* Unbreak strdelim() skipping past quoted strings (bz#1757). For
example, the following directive was not parsed correctly:
AllowUsers "blah blah" blah
* sftp(1): fix swapped args in upload_dir_internal(), breaking
recursive upload depth checks and causing verbose printing of
transfers to always be turned on (bz#1797)
* Fix a longstanding problem where if you suspend scp(1) at the
password/passphrase prompt the terminal mode is not restored.
* Fix a PKCS#11 crash on some smartcards by validating the length
returned for C_GetAttributValue (bz#1773)
* sftp(1): fix ls in working directories that contain globbing
characters in their pathnames (bz#1655)
* Print warning for missing home directory when ChrootDirectory=none
(bz#1564)
* sftp(1): fix a memory leak in do_realpath() error path (bz#1771)
* ssk-keygen(1): Standardise error messages when attempting to open
private key files to include "progname: filename: error reason"
(bz#1783)
* Replace verbose and overflow-prone Linebuf code with
read_keyfile_line() (bz#1565)
* Include the user name on "subsystem request for ..." log messages
* ssh(1) and sshd(8): remove hardcoded limit of 100 permitopen clauses
and port forwards per direction (bz#1327)
* sshd(8): ignore stderr output from subsystems to avoid hangs if a
subsystem or shell initialisation writes to stderr (bz#1750)
* Skip the initial check for access with an empty password when
PermitEmptyPasswords=no (bz#1638)
* sshd(8): fix logspam when key options (from="..." especially) deny
non-matching keys (bz#1765)
* ssh-keygen(1): display a more helpful error message when $HOME is
inaccessible while trying to create .ssh directory (bz#1740)
* ssh(1): fix hang when terminating a mux slave using ~. (bz#1758)
* ssh-keygen(1): refuse to generate keys longer than
OPENSSL_[RD]SA_MAX_MODULUS_BITS, since we would refuse to use
them anyway (bz#1516)
* Suppress spurious tty warning when using -O and stdin is not a tty
(bz#1746)
* Kill channel when pty allocation requests fail. Fixed stuck client
if the server refuses pty allocation (bz#1698)
Portable OpenSSH Bugfixes:
* sshd(8): increase the maximum username length for login recording
to 512 characters (bz#1579)
* Initialize the values to be returned from PAM to sane values in
case the PAM method doesn't write to them. (bz#1795)
* Let configure find OpenSSL libraries in a lib64 subdirectory.
(bz#1756)
Checksums:
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
OpenSSH 5.5 was released on 2010-04-16. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed code
or patches, reported bugs, tested snapshots or donated to the project.
More information on donations may be found at:
http://www.openssh.com/donations.html
This is a bugfix release.
Changes since OpenSSH 5.4
* Unbreak sshd_config's AuthorizedKeysFile option for $HOME-relative paths
* Fix compilation failures on platforms that lack dlopen()
* Include a language tag when sending a protocol 2 disconnection message.
* Make logging of certificates used for user authentication more clear and
consistent between CAs specified using TrustedUserCAKeys and
authorized_keys
Portable OpenSSH:
* Allow contrib/ssh-copy-id to fail gracefully when there are no keys in
the ssh-agent. bz#1723
* Explicitly link libX11 into contrib/gnome-ssh-askpass2. bz#1725
* Allow ChrootDirectory to work in SELinux platforms. bz#1726
* Add configure.ac stanza for Haiku OS. bz#1741
* Enable utmpx support on FreeBSD where possible. bz#1732
* Use pkg-config to determine libedit linker flags where possible. bz#1744
Checksums:
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
OpenSSH 5.4 was released on 2010-03-08. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed code
or patches, reported bugs, tested snapshots or donated to the project.
More information on donations may be found at:
http://www.openssh.com/donations.html
This is a major feature and bugfix release.
Changes since OpenSSH 5.3
Features:
* After a transition period of about 10 years, this release disables
SSH protocol 1 by default. Clients and servers that need to use the
legacy protocol must explicitly enable it in ssh_config / sshd_config
or on the command-line.
* Remove the libsectok/OpenSC-based smartcard code and add support for
PKCS#11 tokens. This support is automatically enabled on all
platforms that support dlopen(3) and was inspired by patches written
by Alon Bar-Lev. Details in the ssh(1) and ssh-add(1) manpages.
* Add support for certificate authentication of users and hosts using a
new, minimal OpenSSH certificate format (not X.509). Certificates
contain a public key, identity information and some validity
constraints and are signed with a standard SSH public key using
ssh-keygen(1). CA keys may be marked as trusted in authorized_keys
or via a TrustedUserCAKeys option in sshd_config(5) (for user
authentication), or in known_hosts (for host authentication).
Documentation for certificate support may be found in ssh-keygen(1),
sshd(8) and ssh(1) and a description of the protocol extensions in
PROTOCOL.certkeys.
* Added a 'netcat mode' to ssh(1): "ssh -W host:port ..." This connects
stdio on the client to a single port forward on the server. This
allows, for example, using ssh as a ProxyCommand to route connections
via intermediate servers. bz#1618
* Add the ability to revoke keys in sshd(8) and ssh(1). User keys may
be revoked using a new sshd_config(5) option "RevokedKeys". Host keys
are revoked through known_hosts (details in the sshd(8) man page).
Revoked keys cannot be used for user or host authentication and will
trigger a warning if used.
* Rewrite the ssh(1) multiplexing support to support non-blocking
operation of the mux master, improve the resilience of the master to
malformed messages sent to it by the slave and add support for
requesting port- forwardings via the multiplex protocol. The new
stdio-to-local forward mode ("ssh -W host:port ...") is also
supported. The revised multiplexing protocol is documented in the
file PROTOCOL.mux in the source distribution.
* Add a 'read-only' mode to sftp-server(8) that disables open in write
mode and all other fs-modifying protocol methods. bz#430
* Allow setting an explicit umask on the sftp-server(8) commandline to
override whatever default the user has. bz#1229
* Many improvements to the sftp(1) client, many of which were
implemented by Carlos Silva through the Google Summer of Code
program:
- Support the "-h" (human-readable units) flag for ls
- Implement tab-completion of commands, local and remote filenames
- Support most of scp(1)'s commandline arguments in sftp(1), as a
first step towards making sftp(1) a drop-in replacement for scp(1).
Note that the rarely-used "-P sftp_server_path" option has been
moved to "-D sftp_server_path" to make way for "-P port" to match
scp(1).
- Add recursive transfer support for get/put and on the commandline
* New RSA keys will be generated with a public exponent of RSA_F4 ==
(2**16)+1 == 65537 instead of the previous value 35.
* Passphrase-protected SSH protocol 2 private keys are now protected
with AES-128 instead of 3DES. This applied to newly-generated keys
as well as keys that are reencrypted (e.g. by changing their
passphrase).
Bugfixes:
* Hold authentication debug messages until after successful
authentication. Fixes a minor information leak of environment
variables specified in authorized_keys if an attacker happens to
know the public key in use.
* When using ChrootDirectory, make sure we test for the existence of
the user's shell inside the chroot and not outside (bz#1679)
* Cache user and group name lookups in sftp-server using
user_from_[ug]id(3) to improve performance on hosts where these
operations are slow (e.g. NIS or LDAP). bz#1495
* Fix problem that prevented passphrase reading from being interrupted
in some circumstances; bz#1590
* Ignore and log any Protocol 1 keys where the claimed size is not
equal to the actual size.
* Make HostBased authentication work with a ProxyCommand. bz#1569
* Avoid run-time failures when specifying hostkeys via a relative
path by prepending the current working directory in these cases.
bz#1290
* Do not prompt for a passphrase if we fail to open a keyfile, and log
the reason why the open failed to debug. bz#1693
* Document that the PubkeyAuthentication directive is allowed in a
sshd_config(5) Match block. bz#1577
* When converting keys, truncate key comments at 72 chars as per
RFC4716. bz#1630
* Do not allow logins if /etc/nologin exists but is not readable by the
user logging in.
* Output a debug log if sshd(8) can't open an existing authorized_keys.
bz#1694
* Quell tc[gs]etattr warnings when forcing a tty (ssh -tt), since we
usually don't actually have a tty to read/set; bz#1686
* Prevent sftp from crashing when given a "-" without a command.
Also, allow whitespace to follow a "-". bz#1691
* After sshd receives a SIGHUP, ignore subsequent HUPs while sshd
re-execs itself. Prevents two HUPs in quick succession from resulting
in sshd dying. bz#1692
* Clarify in sshd_config(5) that StrictModes does not apply to
ChrootDirectory. Permissions and ownership are always checked when
chrooting. bz#1532
* Set close-on-exec on various descriptors so they don't get leaked to
child processes. bz#1643
* Fix very rare race condition in x11/agent channel allocation: don't
read after the end of the select read/write fdset and make sure a
reused FD is not touched before the pre-handlers are called.
* Fix incorrect exit status when multiplexing and channel ID 0 is
recycled. bz#1570
* Fail with an error when an attempt is made to connect to a server
with ForceCommand=internal-sftp with a shell session (i.e. not a
subsystem session). Avoids stuck client when attempting to ssh to
such a service. bz#1606:
* Warn but do not fail if stat()ing the subsystem binary fails. This
helps with chrootdirectory+forcecommand=sftp-server and restricted
shells. bz #1599
* Change "Connecting to host..." message to "Connected to host."
and delay it until after the sftp protocol connection has been
established. Avoids confusing sequence of messages when the
underlying ssh connection experiences problems. bz#1588
* Use the HostKeyAlias rather than the hostname specified on the
commandline when prompting for passwords. bz#1039
* Correct off-by-one in percent_expand(): we would fatal() when trying
to expand EXPAND_MAX_KEYS, allowing only EXPAND_MAX_KEYS-1 to
actually work. Note that nothing in OpenSSH actually uses close to
this limit at present. bz#1607
* Fix passing of empty options from scp(1) and sftp(1) to the
underlying ssh(1). Also add support for the stop option "--".
* Fix an incorrect magic number and typo in PROTOCOL; bz#1688
* Don't escape backslashes when displaying the SSH2 banner. bz#1533
* Don't unnecessarily dup() the in and out fds for sftp-server. bz#1566
* Force use of the correct hash function for random-art signature
display as it was inheriting the wrong one when bubblebabble
signatures were activated. bz#1611
* Do not fall back to adding keys without constraints (ssh-add -c /
-t ...) when the agent refuses the constrained add request. bz#1612
* Fix a race condition in ssh-agent that could result in a wedged or
spinning agent. bz#1633
* Flush stdio before exec() to ensure that everying (motd
in particular) has made it out before the streams go away. bz#1596
* Set FD_CLOEXEC on in/out sockets in sshd(8). bz#1706
Portable OpenSSH Bugfixes:
* Use system's kerberos principal name on AIX if it's available.
bz#1583
* Disable OOM-killing of the listening sshd on Linux. bz#1470
* Use pkg-config for opensc config if it's available. bz#1160
* Unbreak Redhat spec to allow building without askpass. bz#1677
* If PidFile is set in sshd_config, use it in SMF init file. bz#1628
* Print error and usage() when ssh-rand-helper is passed command-
line arguments as none are supported. bz#1568
* Add missing setsockopt() to set IPV6_V6ONLY for local forwarding
with GatwayPorts=yes. bz#1648
* Make GNOME 2 askpass dialog desktop-modal. bz#1645
* If SELinux is enabled set the security context to "sftpd_t" before
running the internal sftp server. bz#1637
* Correctly check libselinux for necessary SELinux functions; bz#1713
* Unbreak builds on Redhat using the supplied openssh.spec; bz#1731
* Fix incorrect privilege dropping order on AIX that prevented
chroot operation; bz#1567
* Call aix_setauthdb/aix_restoredb at the correct times on AIX to
prevent authentication failure; bz#1710
Checksums:
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
OpenSSH 5.3 was released on 2009-10-01. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
This release marks the 10th anniversary of the OpenSSH project.
We would like to thank the OpenSSH community for their support,
especially those who will continue to contribute code or patches,
report bugs, test snapshots or donate to the project during the
next 10 years. More information on donations may be found at:
http://www.openssh.com/donations.html
This is a bugfix release, no new features have been added.
Changes since OpenSSH 5.2
General Bugfixes:
* Do not limit home directory paths to 256 characters. bz#1615
* Several minor documentation and correctness fixes.
Portable OpenSSH Bugfixes:
* This release removes for support for very old versions of Cygwin and
for Windows 95/98/ME
* Move the deletion of PAM credentials on logout to after the session
close. bz#1534
* Make PrintLastLog work on AIX. bz#1595
* Avoid compile errors on FreeBSD from conflicts in glob.h. bz#1634
* Delay dropping of root privileges on AIX so chroot and pam_open_session
work correctly. bz#1249 and bz#1567
* Increase client IO buffer on Cygwin to 64K, realising a significant
performance improvement.
* Roll back bz#1241 (better handling for expired passwords on Tru64).
The change broke password logins on some configurations.
* Accept ENOSYS as a fallback error when attempting atomic
rename(). bz#1535
* Fix passing of variables to recursive make(1) invocations on Solaris.
bz#1505
* Skip the tcgetattr call on the pty master on Solaris, since it never
succeeds and can hang if large amounts of data is sent to the slave
(eg a copy-paste). bz#1528
* Fix detection of krb5-config. bz#1639
* Fix test for server-assigned remote forwarding port for non-root users.
bz#1578
* Fix detection of libresolv on OSX 10.6.
Checksums:
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
OpenSSH 5.2 was released on 2009-02-23. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
We have also recently completed another Internet SSH usage scan, the
results of which may be found at http://www.openssh.com/usage.html
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
http://www.openssh.com/donations.html
The focus of this release has been on bugfixes as the previous
openssh-5.1 release introduced many new features and made some
invasive changes.
Changes since OpenSSH 5.1
Security:
* This release changes the default cipher order to prefer the AES CTR
modes and the revised "arcfour256" mode to CBC mode ciphers that are
susceptible to CPNI-957037 "Plaintext Recovery Attack Against SSH".
* This release also adds countermeasures to mitigate CPNI-957037-style
attacks against the SSH protocol's use of CBC-mode ciphers. Upon
detection of an invalid packet length or Message Authentication
Code, ssh/sshd will continue reading up to the maximum supported
packet length rather than immediately terminating the connection.
This eliminates most of the known differences in behaviour that
leaked information about the plaintext of injected data which formed
the basis of this attack. We believe that these attacks are rendered
infeasible by these changes.
New features:
* Added a -y option to ssh(1) to force logging to syslog rather than
stderr, which is useful when running daemonised (ssh -f)
* The sshd_config(5) ForceCommand directive now accepts commandline
arguments for the internal-sftp server.
* The ssh(1) ~C escape commandline now support runtime creation of
dynamic (-D) port forwards.
* Support the SOCKS4A protocol in ssh(1) dynamic (-D) forwards.
(bz#1482)
* Support remote port forwarding with a listen port of '0'. This
informs the server that it should dynamically allocate a listen
port and report it back to the client. (bz#1003)
* sshd(8) now supports setting PermitEmptyPasswords and
AllowAgentForwarding in Match blocks
Bug and documentation fixes
* Repair a ssh(1) crash introduced in openssh-5.1 when the client is
sent a zero-length banner (bz#1496)
* Due to interoperability problems with certain
broken SSH implementations, the eow@openssh.com and
no-more-sessions@openssh.com protocol extensions are now only sent
to peers that identify themselves as OpenSSH.
* Make ssh(1) send the correct channel number for
SSH2_MSG_CHANNEL_SUCCESS and SSH2_MSG_CHANNEL_FAILURE messages to
avoid triggering 'Non-public channel' error messages on sshd(8) in
openssh-5.1.
* Avoid printing 'Non-public channel' warnings in sshd(8), since the
ssh(1) has sent incorrect channel numbers since ~2004 (this reverts
a behaviour introduced in openssh-5.1).
* Avoid double-free in ssh(1) ~C escape -L handler (bz#1539)
* Correct fail-on-error behaviour in sftp(1) batchmode for remote
stat operations. (bz#1541)
* Disable nonfunctional ssh(1) ~C escape handler in multiplex slave
connections. (bz#1543)
* Avoid hang in ssh(1) when attempting to connect to a server that
has MaxSessions=0 set.
* Multiple fixes to sshd(8) configuration test (-T) mode
* Several core and portable OpenSSH bugs fixed: 1380, 1412, 1418,
1419, 1421, 1490, 1491, 1492, 1514, 1515, 1518, 1520, 1538, 1540
* Many manual page improvements.
Checksums:
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
OpenSSH 5.1 was released on 2008-07-22. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
We have also recently completed another Internet SSH usage scan, the
results of which may be found at http://www.openssh.com/usage.html
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:
http://www.openssh.com/donations.html
Changes since OpenSSH 5.0
Security:
* sshd(8): Avoid X11 man-in-the-middle attack on HP/UX (and possibly
other platforms) when X11UseLocalhost=no
When attempting to bind(2) to a port that has previously been bound
with SO_REUSEADDR set, most operating systems check that either the
effective user-id matches the previous bind (common on BSD-derived
systems) or that the bind addresses do not overlap (Linux and
Solaris).
Some operating systems, such as HP/UX, do not perform these checks
and are vulnerable to an X11 man-in-the-middle attack when the
sshd_config(5) option X11UseLocalhost has been set to "no" - an
attacker may establish a more-specific bind, which will be used in
preference to sshd's wildcard listener.
Modern BSD operating systems, Linux, OS X and Solaris implement the
above checks and are not vulnerable to this attack, nor are systems
where the X11UseLocalhost has been left at the default value of
"yes".
Portable OpenSSH 5.1 avoids this problem for all operating systems
by not setting SO_REUSEADDR when X11UseLocalhost is set to no.
This vulnerability was reported by sway2004009 AT hotmail.com.
New features:
* Introduce experimental SSH Fingerprint ASCII Visualisation to ssh(1)
and ssh-keygen(1). Visual fingerprinnt display is controlled by a new
ssh_config(5) option "VisualHostKey". The intent is to render
SSH host keys in a visual form that is amenable to easy recall and
rejection of changed host keys. This technique inspired by the
graphical hash visualisation schemes known as "random art[*]", and
by Dan Kaminsky's musings at 23C3 in Berlin.
Fingerprint visualisation in is currently disabled by default, as the
algorithm used to generate the random art is still subject to change.
[*] "Hash Visualization: a New Technique to improve Real-World
Security", Perrig A. and Song D., 1999, International Workshop on
Cryptographic Techniques and E-Commerce (CrypTEC '99)
http://sparrow.ece.cmu.edu/~adrian/projects/validation/validation.pdf
* sshd_config(5) now supports CIDR address/masklen matching in "Match
address" blocks, with a fallback to classic wildcard matching. For
example:
Match address 192.0.2.0/24,3ffe:ffff::/32,!10.*
PasswordAuthentication yes
* sshd(8) now supports CIDR matching in ~/.ssh/authorized_keys
from="..." restrictions, also with a fallback to classic wildcard
matching.
* Added an extended test mode (-T) to sshd(8) to request that it write
its effective configuration to stdout and exit. Extended test mode
also supports the specification of connection parameters (username,
source address and hostname) to test the application of
sshd_config(5) Match rules.
* ssh(1) now prints the number of bytes transferred and the overall
connection throughput for SSH protocol 2 sessions when in verbose
mode (previously these statistics were displayed for protocol 1
connections only).
* sftp-server(8) now supports extension methods statvfs@openssh.com and
fstatvfs@openssh.com that implement statvfs(2)-like operations.
(bz#1399)
* sftp(1) now has a "df" command to the sftp client that uses the
statvfs@openssh.com to produce a df(1)-like display of filesystem
space and inode utilisation (requires statvfs@openssh.com support on
the server)
* Added a MaxSessions option to sshd_config(5) to allow control of the
number of multiplexed sessions supported over a single TCP connection.
This allows increasing the number of allowed sessions above the
previous default of 10, disabling connection multiplexing
(MaxSessions=1) or disallowing login/shell/subsystem sessions
entirely (MaxSessions=0).
* Added a no-more-sessions@openssh.com global request extension that is
sent from ssh(1) to sshd(8) when the client knows that it will never
request another session (i.e. when session multiplexing is disabled).
This allows a server to disallow further session requests and
terminate the session in cases where the client has been hijacked.
* ssh-keygen(1) now supports the use of the -l option in combination
with -F to search for a host in ~/.ssh/known_hosts and display its
fingerprint.
* ssh-keyscan(1) now defaults to "rsa" (protocol 2) keys, instead of
"rsa1".
* Added an AllowAgentForwarding option to sshd_config(8) to control
whether authentication agent forwarding is permitted. Note that this
is a loose control, as a client may install their own unofficial
forwarder.
* ssh(1) and sshd(8): avoid unnecessary malloc/copy/free when receiving
network data, resulting in a ~10% speedup
* ssh(1) and sshd(8) will now try additional addresses when connecting
to a port forward destination whose DNS name resolves to more than
one address. The previous behaviour was to try the only first address
and give up if that failed. (bz#383)
* ssh(1) and sshd(8) now support signalling that channels are
half-closed for writing, through a channel protocol extension
notification "eow@openssh.com". This allows propagation of closed
file descriptors, so that commands such as:
"ssh -2 localhost od /bin/ls | true"
do not send unnecessary data over the wire. (bz#85)
* sshd(8): increased the default size of ssh protocol 1 ephemeral keys
from 768 to 1024 bits.
* When ssh(1) has been requested to fork after authentication
("ssh -f") with ExitOnForwardFailure enabled, delay the fork until
after replies for any -R forwards have been seen. Allows for robust
detection of -R forward failure when using -f. (bz#92)
* "Match group" blocks in sshd_config(5) now support negation of
groups. E.g. "Match group staff,!guests" (bz#1315)
* sftp(1) and sftp-server(8) now allow chmod-like operations to set
set[ug]id/sticky bits. (bz#1310)
* The MaxAuthTries option is now permitted in sshd_config(5) match
blocks.
* Multiplexed ssh(1) sessions now support a subset of the ~ escapes
that are available to a primary connection. (bz#1331)
* ssh(1) connection multiplexing will now fall back to creating a new
connection in most error cases. (bz#1439 bz#1329)
* Added some basic interoperability tests against Twisted Conch.
* Documented OpenSSH's extensions to and deviations from the published
SSH protocols (the PROTOCOL file in the distribution)
* Documented OpenSSH's ssh-agent protocol (PROTOCOL.agent).
Bug and documentation fixes
* Make ssh(1) deal more gracefully with channel requests that fail.
Previously it would optimistically assume that requests would always
succeed, which could cause hangs if they did not (e.g. when the
server runs out of file descriptors). (bz#1384)
* ssh(1) now reports multiplexing errors via the multiplex slave's
stderr where possible (subject to LogLevel in the mux master).
* ssh(1) and sshd(8) now send terminate protocol banners with CR+LF for
protocol 2 to comply with RFC 4253. Previously they were terminated
with CR alone. Protocol 1 banners remain CR terminated. (bz#1443)
* Merged duplicate authentication file checks in sshd(8) and refuse to
read authorised_keys and .shosts from non-regular files. (bz#1438)
* Ensure that sshd(8)'s umask disallows at least group and world write,
even if a more permissive one has been inherited. (bz#1433)
* Suppress the warning message from sshd(8) when changing to a
non-existent user home directory after chrooting. (bz#1461)
* Mention that scp(1) follows symlinks when performing recursive
copies. (bz#1466)
* Prevent sshd(8) from erroneously applying public key restrictions
leaned from ~/.ssh/authorized_keys to other authentication methods
when public key authentication subsequently fails. (bz#1472)
* Fix protocol keepalive timeouts - in some cases, keepalive packets
were being sent, but the connection was not being closed when the
limit for missing replies was exceeded. (bz#1465)
* Fix ssh(1) sending invalid TTY modes when a TTY was forced (ssh -tt)
but stdin was not a TTY. (bz#1199)
* ssh(1) will now exit with a non-zero exit status if
ExitOnForwardFailure was set and forwardings were disabled due to a
failed host key check.
* Fix MaxAuthTries tests to disallow a free authentication try to
clients that skipped the protocol 2 "none" authentication method.
(part of bz#1432)
* Make keepalive timeouts apply while synchronously waiting
for a packet, particularly during key renegotiation. (bz#1363)
* sshd(8) has been audited to eliminate fd leaks and calls to fatal()
in conditions of file descriptor exhaustion.
Portable OpenSSH-specific bugfixes
* Avoid a sshd(8) hang-on-exit on Solaris caused by depending on the
success of isatty() on a PTY master (undefined behaviour). Probably
affected other platforms too. (bz#1463)
* Fixed test for locked accounts on HP/UX with shadowed
passwords disabled. (bz#1083)
* Disable poll() fallback in atomiciov for Tru64. readv
doesn't seem to be a comparable object there, which lead to
compilation errors. (bz#1386)
* Fall back to racy rename if link returns EXDEV. (bz#1447)
* Explicitly handle EWOULDBLOCK wherever we handle EAGAIN, on
some platforms (HP nonstop) it is a distinct errno. (bz#1467)
* Avoid NULL dereferences in ancient sigaction replacement
code. (bz#1240)
* Avoid linking against libgssapi, which despite its name
doesn't seem to implement all of GSSAPI. (bz#1276)
* Use explicit noreturn attribute instead of __dead, fixing
compilation problems on Interix. (bz#1112)
* Added support password expiry on Tru64 SIA systems. (bz#1241)
* Fixed an UMAC alignment problem that manifested on Itanium
platforms. (bz#1462)
* The sftp-server(8) manual now describes the requirements for
transfer logging in chroot environments. (bz#1488)
* Strip trailing dot from hostnames when the sshd_config(5)
HostbasedUsesNameFromPacketOnly option is set. (bz#1200)
Checksums:
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
OpenSSH 5.0 was released on 2008-04-03. It is available from the
mirrors listed at https://www.openssh.com/.
We apologise for any inconvenience resulting from this release
being made so shortly after 4.9. Unfortunately we only learned of
the below security issue from the public CVE report. The Debian
OpenSSH maintainers responsible for handling the initial report of
this bug failed to report it via either the private OpenSSH security
contact list (openssh@openssh.com) or the portable OpenSSH Bugzilla
(http://bugzilla.mindrot.org/).
We ask anyone wishing to report security bugs in OpenSSH to please use
the openssh@openssh.com contact and to practice responsible disclosure.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots and purchased
T-shirts or posters.
T-shirt, poster and CD sales directly support the project. Pictures
and more information can be found at:
http://www.openbsd.org/tshirts.html and
http://www.openbsd.org/orders.html
For international orders use http://https.openbsd.org/cgi-bin/order
and for European orders, use http://https.openbsd.org/cgi-bin/order.eu
Changes since OpenSSH 4.9:
Security:
* CVE-2008-1483: Avoid possible hijacking of X11-forwarded connections
by refusing to listen on a port unless all address families bind
successfully.
Checksums:
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
OpenSSH 4.9 was released on 2008-03-31. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots and purchased
T-shirts or posters.
T-shirt, poster and CD sales directly support the project. Pictures
and more information can be found at:
http://www.openbsd.org/tshirts.html and
http://www.openbsd.org/orders.html
For international orders use http://https.openbsd.org/cgi-bin/order
and for European orders, use http://https.openbsd.org/cgi-bin/order.eu
Note that OpenSSH 4.8 was an OpenBSD-only release shipped with the
OpenBSD 4.3 CD.
Changes since OpenSSH 4.7:
Security:
* Disable execution of ~/.ssh/rc for sessions where a command has been
forced by the sshd_config ForceCommand directive. Users who had
write access to this file could use it to execute arbitrary commands.
This behaviour was documented, but was an unsafe default and an extra
hassle for administrators.
New features:
* Added chroot(2) support for sshd(8), controlled by a new option
"ChrootDirectory". Please refer to sshd_config(5) for details, and
please use this feature carefully. (bz#177 bz#1352)
* Linked sftp-server(8) into sshd(8). The internal sftp server is
used when the command "internal-sftp" is specified in a Subsystem
or ForceCommand declaration. When used with ChrootDirectory, the
internal sftp server requires no special configuration of files
inside the chroot environment. Please refer to sshd_config(5) for
more information.
* Added a "no-user-rc" option for authorized_keys to disable execution
of ~/.ssh/rc
* Added a protocol extension method "posix-rename@openssh.com" for
sftp-server(8) to perform POSIX atomic rename() operations.
(bz#1400)
* Removed the fixed limit of 100 file handles in sftp-server(8). The
server will now dynamically allocate handles up to the number of
available file descriptors. (bz#1397)
* ssh(8) will now skip generation of SSH protocol 1 ephemeral server
keys when in inetd mode and protocol 2 connections are negotiated.
This speeds up protocol 2 connections to inetd-mode servers that
also allow Protocol 1 (bz#440)
* Accept the PermitRootLogin directive in a sshd_config(5) Match
block. Allows for, e.g. permitting root only from the local
network.
* Reworked sftp(1) argument splitting and escaping to be more
internally consistent (i.e. between sftp commands) and more
consistent with sh(1). Please note that this will change the
interpretation of some quoted strings, especially those with
embedded backslash escape sequences. (bz#778)
* Support "Banner=none" in sshd_config(5) to disable sending of a
pre-login banner (e.g. in a Match block).
* ssh(1) ProxyCommands are now executed with $SHELL rather than
/bin/sh.
* ssh(1)'s ConnectTimeout option is now applied to both the TCP
connection and the SSH banner exchange (previously it just covered
the TCP connection). This allows callers of ssh(1) to better detect
and deal with stuck servers that accept a TCP connection but don't
progress the protocol, and also makes ConnectTimeout useful for
connections via a ProxyCommand.
* Many new regression tests, including interop tests against PuTTY's
plink.
* Support BSM auditing on Mac OS X
The following bugs have been fixed in this release:
- scp(1) incorrectly reported "stalled" on slow copies. (bz#799)
- scp(1) date underflow for timestamps before epoch. (bz#828)
- scp(1) and sftp(1) progressmeter type fixes. (bz#842)
- SSH2_MSG_UNIMPLEMENTED packets did not correctly reset the client
keepalive logic, causing disconnections on servers that did not
explicitly implement "keepalive@openssh.com". (bz#1307)
- ssh(1) used the obsolete SIG DNS RRtype for host keys in DNS,
instead of the current standard RRSIG. (bz#1317)
- Extract magic buffer size constants in scp(1) to #defines.
(bz#1333)
- Correctly drain ACKs when a sftp(1) upload write fails midway,
avoids a fatal() exit from what should be a recoverable condition.
(bz#1354)
- Avoid pointer arithmetic and strict aliasing warnings. (bz#1355)
- Fixed packet size advertisements. Previously TCP and agent
forwarding incorrectly advertised the channel window size as the
packet size, causing fatal errors under some conditions. (bz#1360)
- Document KbdInteractiveAuthentication in sshd_config(5). (bz#1367)
- Fixed sftp(1) file handle leak on download when the local file
could not be opened. (bz#1375)
- Fixed ssh-keygen(1) selective host key hashing (i.e.
"ssh-keygen -HF hostname") to not include any IP address in the
data to be hashed. (bz#1376)
- Fix clobbering of struct passwd from multiple getpwid calls,
resulting in fatal errors inside tilde_expand_filename. (bz#1377)
- Fix parsing of port-forwarding specifications to correctly
detect errors in either specified port number. (bz#1378)
- Fix memory leak in ssh(1) ~ escape commandline handling. (bz#1379)
- Make ssh(1) skip listening on the IPv6 wildcard address when a
binding address of 0.0.0.0 is used against an old SSH server that
does not support the RFC4254 syntax for wildcard bind addresses.
(bz#1381)
- Remove extra backslashes in the RB_PROTOTYPE macro definition.
(bz#1385)
- Support ssh(1) RekeyLimits up to the maximum allowed by the
protocol: 2**32-1. (bz#1390)
- Enable IPV6_V6ONLY socket option on sshd(8) listen socket, as is
already done for X11/TCP forwarding sockets. (bz#1392)
- Fix FD leak that could hang a ssh(1) connection multiplexing
master. (bz#1398)
- Improve error messages when hostname resolution fails due to a
system error. (bz#1417)
- Make ssh(1) -q option documentation consistent with reality.
(bz#1427 bz#1429)
Portable OpenSSH bugs fixed:
- Fixed sshd(8) PAM support not calling pam_session_close(), or
failing to call it with root privileges. (bz#926)
- Made sshd(8) use configuration-specified SyslogFacility for
hosts_access(3) messages for denied connections. (bz#1042)
- Implement getgrouplist(3) for AIX, enabling NSS LDAP to work on
this platform. (bz#1081)
- Fix compilation errors on AIX due to misdefinition of LLONG_MAX.
(bz#1347)
- Force use of local glob(3) implementation on Mac OS X and FreeBSD,
as the platform versions lack features or have unexpected
behaviour. (bz#1407)
- Reduce stdout/stderr noise from ssh-copy-id. (bz#1431)
- Fix activation of OpenSSL engine support when requested in
configure. (bz#1437)
Checksums:
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
OpenSSH 4.8 was an OpenBSD-only release, included on the OpenBSD 4.3
CD only.
Changes since OpenSSH 4.8:
New features:
* Added chroot(2) support for sshd(8), controlled by a new option
"ChrootDirectory". Please refer to sshd_config(5) for details, and
please use this feature carefully. (bz#177 bz#1352)
* Linked sftp-server(8) into sshd(8). The internal sftp server is
used when the command "internal-sftp" is specified in a Subsystem
or ForceCommand declaration. When used with ChrootDirectory, the
internal sftp server requires no special configuration of files
inside the chroot environment. Please refer to sshd_config(5) for
more information.
* Added a protocol extension method "posix-rename@openssh.com" for
sftp-server(8) to perform POSIX atomic rename() operations.
(bz#1400)
* Removed the fixed limit of 100 file handles in sftp-server(8). The
server will now dynamically allocate handles up to the number of
available file descriptors. (bz#1397)
* ssh(8) will now skip generation of SSH protocol 1 ephemeral server
keys when in inetd mode and protocol 2 connections are negotiated.
This speeds up protocol 2 connections to inetd-mode servers that
also allow Protocol 1 (bz#440)
* Accept the PermitRootLogin directive in a sshd_config(5) Match
block. Allows for, e.g. permitting root only from the local
network.
* Reworked sftp(1) argument splitting and escaping to be more
internally consistent (i.e. between sftp commands) and more
consistent with sh(1). Please note that this will change the
interpretation of some quoted strings, especially those with
embedded backslash escape sequences. (bz#778)
* Support "Banner=none" in sshd_config(5) to disable sending of a
pre-login banner (e.g. in a Match block).
* ssh(1) ProxyCommands are now executed with $SHELL rather than
/bin/sh.
* ssh(1)'s ConnectTimeout option is now applied to both the TCP
connection and the SSH banner exchange (previously it just covered
the TCP connection). This allows callers of ssh(1) to better detect
and deal with stuck servers that accept a TCP connection but don't
progress the protocol, and also makes ConnectTimeout useful for
connections via a ProxyCommand.
* Many new regression tests, including interop tests against PuTTY's
plink.
* Support BSM auditing on Mac OS X
The following bugs have been fixed in this release:
- scp(1) incorrectly reported "stalled" on slow copies. (bz#799)
- scp(1) date underflow for timestamps before epoch. (bz#828)
- scp(1) and sftp(1) progressmeter type fixes. (bz#842)
- SSH2_MSG_UNIMPLEMENTED packets did not correctly reset the client
keepalive logic, causing disconnections on servers that did not
explicitly implement "keepalive@openssh.com". (bz#1307)
- ssh(1) used the obsolete SIG DNS RRtype for host keys in DNS,
instead of the current standard RRSIG. (bz#1317)
- Extract magic buffer size constants in scp(1) to #defines.
(bz#1333)
- Correctly drain ACKs when a sftp(1) upload write fails midway,
avoids a fatal() exit from what should be a recoverable condition.
(bz#1354)
- Avoid pointer arithmetic and strict aliasing warnings. (bz#1355)
- Fixed packet size advertisements. Previously TCP and agent
forwarding incorrectly advertised the channel window size as the
packet size, causing fatal errors under some conditions. (bz#1360)
- Document KbdInteractiveAuthentication in sshd_config(5). (bz#1367)
- Fixed sftp(1) file handle leak on download when the local file
could not be opened. (bz#1375)
- Fixed ssh-keygen(1) selective host key hashing (i.e.
"ssh-keygen -HF hostname") to not include any IP address in the
data to be hashed. (bz#1376)
- Fix clobbering of struct passwd from multiple getpwid calls,
resulting in fatal errors inside tilde_expand_filename. (bz#1377)
- Fix parsing of port-forwarding specifications to correctly
detect errors in either specified port number. (bz#1378)
- Fix memory leak in ssh(1) ~ escape commandline handling. (bz#1379)
- Make ssh(1) skip listening on the IPv6 wildcard address when a
binding address of 0.0.0.0 is used against an old SSH server that
does not support the RFC4254 syntax for wildcard bind addresses.
(bz#1381)
- Remove extra backslashes in the RB_PROTOTYPE macro definition.
(bz#1385)
- Support ssh(1) RekeyLimits up to the maximum allowed by the
protocol: 2**32-1. (bz#1390)
- Enable IPV6_V6ONLY socket option on sshd(8) listen socket, as is
already done for X11/TCP forwarding sockets. (bz#1392)
- Fix FD leak that could hang a ssh(1) connection multiplexing
master. (bz#1398)
- Improve error messages when hostname resolution fails due to a
system error. (bz#1417)
- Make ssh(1) -q option documentation consistent with reality.
(bz#1427 bz#1429)
Portable OpenSSH bugs fixed:
- Fixed sshd(8) PAM support not calling pam_session_close(), or
failing to call it with root privileges. (bz#926)
- Made sshd(8) use configuration-specified SyslogFacility for
hosts_access(3) messages for denied connections. (bz#1042)
- Implement getgrouplist(3) for AIX, enabling NSS LDAP to work on
this platform. (bz#1081)
- Fix compilation errors on AIX due to misdefinition of LLONG_MAX.
(bz#1347)
- Force use of local glob(3) implementation on Mac OS X and FreeBSD,
as the platform versions lack features or have unexpected
behaviour. (bz#1407)
- Reduce stdout/stderr noise from ssh-copy-id. (bz#1431)
- Fix activation of OpenSSL engine support when requested in
configure. (bz#1437)
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
OpenSSH 4.7 was released on 2007-09-05. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots and purchased
T-shirts or posters.
T-shirt, poster and CD sales directly support the project. Pictures
and more information can be found at:
http://www.openbsd.org/tshirts.html and
http://www.openbsd.org/orders.html
For international orders use http://https.openbsd.org/cgi-bin/order
and for European orders, use http://https.openbsd.org/cgi-bin/order.eu
Changes since OpenSSH 4.6:
Security bugs resolved in this release:
* Prevent ssh(1) from using a trusted X11 cookie if creation of an
untrusted cookie fails; found and fixed by Jan Pechanec.
Other changes, new functionality and fixes in this release:
* sshd(8) in new installations defaults to SSH Protocol 2 only.
Existing installations are unchanged.
* The SSH channel window size has been increased, and both ssh(1)
sshd(8) now send window updates more aggressively. These improves
performance on high-BDP (Bandwidth Delay Product) networks.
* ssh(1) and sshd(8) now preserve MAC contexts between packets, which
saves 2 hash calls per packet and results in 12-16% speedup for
arcfour256/hmac-md5.
* A new MAC algorithm has been added, UMAC-64 (RFC4418) as
"umac-64@openssh.com". UMAC-64 has been measured to be
approximately 20% faster than HMAC-MD5.
* A -K flag was added to ssh(1) to set GSSAPIAuthentication=Yes
* Failure to establish a ssh(1) TunnelForward is now treated as a
fatal error when the ExitOnForwardFailure option is set.
* ssh(1) returns a sensible exit status if the control master goes
away without passing the full exit status. (bz #1261)
* The following bugs have been fixed in this release:
- When using a ProxyCommand in ssh(1), set the outgoing hostname with
gethostname(2), allowing hostbased authentication to work (bz #616)
- Make scp(1) skip FIFOs rather than hanging (bz #856)
- Encode non-printing characters in scp(1) filenames.
these could cause copies to be aborted with a "protocol error"
(bz #891)
- Handle SIGINT in sshd(8) privilege separation child process to
ensure that wtmp and lastlog records are correctly updated
(bz #1196)
- Report GSSAPI mechanism in errors, for libraries that support
multiple mechanisms (bz #1220)
- Improve documentation for ssh-add(1)'s -d option (bz #1224)
- Rearrange and tidy GSSAPI code, removing server-only code being
linked into the client. (bz #1225)
- Delay execution of ssh(1)'s LocalCommand until after all forwadings
have been established. (bz #1232)
- In scp(1), do not truncate non-regular files (bz #1236)
- Improve exit message from ControlMaster clients. (bz #1262)
- Prevent sftp-server(8) from reading until it runs out of buffer
space, whereupon it would exit with a fatal error. (bz #1286)
* Portable OpenSSH bugs fixed:
- Fix multiple inclusion of paths.h on AIX 5.1 systems. (bz #1243)
- Implement getpeereid for Solaris using getpeerucred. Solaris
systems will now refuse ssh-agent(1) and ssh(1) ControlMaster
clients from different, non-root users (bz #1287)
- Fix compilation warnings by including string.h if found. (bz #1294)
- Remove redefinition of _res in getrrsetbyname.c for platforms that
already define it. (bz #1299)
- Fix spurious "chan_read_failed for istate 3" errors from sshd(8),
a side-effect of the "hang on exit" fix introduced in 4.6p1.
(bz #1306)
- pam_end() was not being called if authentication failed (bz #1322)
- Fix SELinux support when SELinux is in permissive mode. Previously
sshd(8) was treating SELinux errors as always fatal. (bz #1325)
- Ensure that pam_setcred(..., PAM_ESTABLISH_CRED) is called before
pam_setcred(..., PAM_REINITIALIZE_CRED), fixing pam_dhkeys.
(bz #1339)
- Fix privilege separation on QNX - pre-auth only, this platform does
not support file descriptor passing needed for post-auth privilege
separation. (bz #1343)
Thanks to everyone who has contributed patches, reported bugs and
tested releases.
Checksums:
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
OpenSSH 4.6 was released on 2007-03-09. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots and purchased
T-shirts or posters.
T-shirt, poster and CD sales directly support the project. Pictures
and more information can be found at:
http://www.openbsd.org/tshirts.html and
http://www.openbsd.org/orders.html
For international orders use http://https.openbsd.org/cgi-bin/order
and for European orders, use http://https.openbsd.org/cgi-bin/order.eu
Changes since OpenSSH 4.5:
* sshd now allows the enabling and disabling of authentication
methods on a per user, group, host and network basis via the
Match directive in sshd_config.
* The following bugs have been fixed in this release:
- Clear SIGALRM when restarting due to SIGHUP. Prevents stray
signal from taking down sshd if a connection was pending at
the time SIGHUP was received
- sftp returned a zero exit status when upload failed due to write
errors (bugzilla #1252)
- fixed an inconsistent check for a terminal when displaying scp
progress meter (bugzilla #1265)
- Parsing of time values in Match blocks was incorrectly applied
to the global configuration (bugzilla #1275)
- Allow multiple forwarding options to work when specified in a
PermitOpen directive (bugzilla #1267)
- Interoperate with ssh.com versions that do not support binding
remote port forwarding sessions to a hostname (bugzilla #1019)
* Portable OpenSSH bugs fixed:
- "hang on exit" when background processes are running at the time
of exit on a ttyful/login session (bugzilla #52)
- Fix typos in the ssh-rand-helper(8) man page (bugzilla #1259)
- Check that some SIG records have been returned in getrrsetbyname
(bugzilla #1281)
- Fix contrib/findssl for platforms that lack "which" (bugzilla
#1237)
- Work around bug in OpenSSL 0.9.8e that broke aes256-ctr,
aes192-ctr, arcfour256 (bugzilla #1291)
Checksums:
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
OpenSSH 4.5 was released on 2006-11-07. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots and purchased
T-shirts or posters.
T-shirt, poster and CD sales directly support the project. Pictures
and more information can be found at:
http://www.openbsd.org/tshirts.html and
http://www.openbsd.org/orders.html
For international orders use http://https.openbsd.org/cgi-bin/order
and for European orders, use http://https.openbsd.org/cgi-bin/order.eu
Changes since OpenSSH 4.4:
This is a bugfix only release. No new features have been added.
Security bugs resolved in this release:
* Fix a bug in the sshd privilege separation monitor that weakened its
verification of successful authentication. This bug is not known to
be exploitable in the absence of additional vulnerabilities.
This release includes the following non-security fixes:
* Several compilation fixes for portable OpenSSH
* Fixes to Solaris SMF/process contract support (bugzilla #1255)
Thanks to everyone who has contributed patches, reported bugs and
tested releases.
Checksums:
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
OpenSSH 4.4 was released on 2006-09-27. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots and purchased
T-shirts or posters.
T-shirt, poster and CD sales directly support the project. Pictures
and more information can be found at:
http://www.openbsd.org/tshirts.html and
http://www.openbsd.org/orders.html
For international orders use http://https.openbsd.org/cgi-bin/order
and for European orders, use http://https.openbsd.org/cgi-bin/order.eu
Changes since OpenSSH 4.3:
Security bugs resolved in this release:
* Fix a pre-authentication denial of service found by Tavis Ormandy,
that would cause sshd(8) to spin until the login grace time
expired.
* Fix an unsafe signal handler reported by Mark Dowd. The signal
handler was vulnerable to a race condition that could be exploited
to perform a pre-authentication denial of service. On portable
OpenSSH, this vulnerability could theoretically lead to
pre-authentication remote code execution if GSSAPI authentication
is enabled, but the likelihood of successful exploitation appears
remote.
* On portable OpenSSH, fix a GSSAPI authentication abort that could
be used to determine the validity of usernames on some platforms.
This release includes the following new functionality and fixes:
* Implemented conditional configuration in sshd_config(5) using the
"Match" directive. This allows some configuration options to be
selectively overridden if specific criteria (based on user, group,
hostname and/or address) are met. So far a useful subset of post-
authentication options are supported and more are expected to be
added in future releases.
* Add support for Diffie-Hellman group exchange key agreement with a
final hash of SHA256.
* Added a "ForceCommand" directive to sshd_config(5). Similar to the
command="..." option accepted in ~/.ssh/authorized_keys, this forces
the execution of the specified command regardless of what the user
requested. This is very useful in conjunction with the new "Match"
option.
* Add a "PermitOpen" directive to sshd_config(5). This mirrors the
permitopen="..." authorized_keys option, allowing fine-grained
control over the port-forwardings that a user is allowed to
establish.
* Add optional logging of transactions to sftp-server(8).
* ssh(1) will now record port numbers for hosts stored in
~/.ssh/authorized_keys when a non-standard port has been requested.
* Add an "ExitOnForwardFailure" option to cause ssh(1) to exit (with
a non-zero exit code) when requested port forwardings could not be
established.
* Extend sshd_config(5) "SubSystem" declarations to allow the
specification of command-line arguments.
* Replacement of all integer overflow susceptible invocations of
malloc(3) and realloc(3) with overflow-checking equivalents.
* Many manpage fixes and improvements
* New portable OpenSSH-specific features:
Add optional support for SELinux, controlled using the
--with-selinux configure option (experimental)
Add optional support for Solaris process contracts, enabled
using the --with-solaris-contracts configure option (experimental)
This option will also include SMF metadata in Solaris packages
built using the "make package" target
Add optional support for OpenSSL hardware accelerators (engines),
enabled using the --with-ssl-engine configure option.
* Bugs from http://bugzilla.mindrot.org fixed:
#482 - readconf doesn't accept paths with spaces in them.
#906 - syslog messages from sshd [net] lost.
#975 - Kerberos authentication timing can leak information
about account validity.
#981 - Flow stop in SSH2.
#1102 - C program 'write' with zero length hangs.
#1129 - sshd hangs for command-only invocations due to
fork/child signals.
#1131 - error "buffer_append_space:alloc not supported"
#1138 - Passphrase asked for (but ignored) if key file permissions
too liberal..
#1156 - Closes connection after C-c is pressed on QNX.
#1157 - ssh-keygen doesn't handle DOS line breaks.
#1159 - %u and %h not handled in IdentityFile.
#1161 - scp -r fails.
#1162 - Inappropriate sequence of syslog messages.
#1166 - openssh-4.3p1 has some issues compiling.
#1171 - configure can't always figure out LLONG_MAX..
#1173 - scp reports lost connection for very large files.
#1177 - Incorrect sshrc file location in Makefile.in.
#1179 - sshd incorrectly rejects connections due to IP options.
#1181 - configure should detect when openssl-0.9.8x needs -ldl.
#1186 - ssh tries multiple times to open unprotected keys.
#1188 - keyboard-interactive should not allow retry after
pam_acct_mgmt fails.
#1193 - Open ssh will not allow changing of passwords on usernames
greater than 8 characters..
#1201 - Bind address information is not specified in command line
help messages.
#1203 - configure.ac is missing an open [.
#1207 - sshd does not clear unsuccessful login count on
non-interactive logins.
#1218 - GSSAPI client code permits SPNEGO usage.
#1221 - Banner only suppressed at log level = QUIET (used to be
at log level < INFO).
* Fixes to memory and file descriptor leaks reported by the Coverity
static analysis tool
* Fixes to inconsistent pointer checks reported by the Stanford
SATURN tool
Thanks to everyone who has contributed patches, reported bugs and
tested releases.
Checksums:
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
Portable OpenSSH 4.3p2 was released on 2006-02-11. It will be available
from the mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
We have also recently completed another Internet SSH usage scan, the
results of which may be found at http://www.openssh.com/usage.html
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots and purchased
T-shirts or posters.
T-shirt, poster and CD sales directly support the project. Pictures
and more information can be found at:
http://www.openbsd.org/tshirts.html and
http://www.openbsd.org/orders.html
For international orders use http://https.openbsd.org/cgi-bin/order
and for European orders, use http://https.openbsd.org/cgi-bin/order.eu
Changes since Portable OpenSSH 4.3p1:
This is a release of Portable OpenSSH only, to resolve some
portability bugs. There are no new features, only fixes:
* Explicitly test for egrep in ./configure, fixing a problem in 4.3p1
that caused some platforms to fail to detect the available fields
in utmp/wtmp/lastlog records. This bug manifested as missing or
empty login/logout records (as seen by last(1), etc.)
* Fix for logout records not being updated on platforms without
support for post-authentication privilege separation (e.g. Cygwin)
* Fixed compilation problems on Ultrix, NewsOS and QNX
Thanks to everyone who has contributed patches, reported bugs or test
releases.
Checksums:
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
OpenSSH 4.3 was released on 2006-02-01. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
We have also recently completed another Internet SSH usage scan, the
results of which may be found at http://www.openssh.com/usage.html
Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots and purchased
T-shirts or posters.
T-shirt, poster and CD sales directly support the project. Pictures
and more information can be found at:
http://www.openbsd.org/tshirts.html and
http://www.openbsd.org/orders.html
For international orders use http://https.openbsd.org/cgi-bin/order
and for European orders, use http://https.openbsd.org/cgi-bin/order.eu
Changes since OpenSSH 4.2:
Security bugs resolved in this release:
* CVE-2006-0225: scp (as does rcp, on which it is based) invoked a
subshell to perform local to local, and remote to remote copy
operations. This subshell exposed filenames to shell expansion
twice; allowing a local attacker to create filenames containing
shell metacharacters that, if matched by a wildcard, could lead
to execution of attacker-specified commands with the privilege of
the user running scp (Bugzilla #1094)
This is primarily a bug-fix release, only one new feature has been
added:
* Add support for tunneling arbitrary network packets over a
connection between an OpenSSH client and server via tun(4) virtual
network interfaces. This allows the use of OpenSSH (4.3+) to create
a true VPN between the client and server providing real network
connectivity at layer 2 or 3. This feature is experimental and is
currently supported on OpenBSD, Linux, NetBSD (IPv4 only) and
FreeBSD. Other operating systems with tun/tap interface capability
may be added in future portable OpenSSH releases. Please refer to
the README.tun file in the source distribution for further details
and usage examples.
Some of the other bugs resolved and internal improvements are:
* Reduce default key length for new DSA keys generated by ssh-keygen
back to 1024 bits. DSA is not specified for longer lengths and does
not fully benefit from simply making keys longer. As per FIPS 186-2
Change Notice 1, ssh-keygen will refuse to generate a new DSA key
smaller or larger than 1024 bits
* Fixed X forwarding failing to start when a the X11 client is executed
in background at the time of session exit (Bugzilla #1086)
* Change ssh-keygen to generate a protocol 2 RSA key when invoked
without arguments (Bugzilla #1064)
* Fix timing variance for valid vs. invalid accounts when attempting
Kerberos authentication (Bugzilla #975)
* Ensure that ssh always returns code 255 on internal error (Bugzilla
#1137)
* Cleanup wtmp files on SIGTERM when not using privsep (Bugzilla #1029)
* Set SO_REUSEADDR on X11 listeners to avoid problems caused by
lingering sockets from previous session (X11 applications can
sometimes not connect to 127.0.0.1:60xx) (Bugzilla #1076)
* Ensure that fds 0, 1 and 2 are always attached in all programs, by
duping /dev/null to them if necessary.
* Xauth list invocation had bogus "." argument (Bugzilla #1082)
* Remove internal assumptions on key exchange hash algorithm and output
length, preparing OpenSSH for KEX methods with alternate hashes.
* Ignore junk sent by a server before it sends the "SSH-" banner
(Bugzilla #1067)
* The manpages has been significantly improves and rearranged, in
addition to other specific manpage fixes:
#1037 - Man page entries for -L and -R should mention -g.
#1077 - Descriptions for "ssh -D" and DynamicForward should mention
they can specify "bind_address" optionally.
#1088 - Incorrect descriptions in ssh_config man page for
ControlMaster=no.
#1121 - Several corrections for ssh_agent manpages
* Lots of cleanups, including fixes to memory leaks on error paths
(Bugzilla #1109, #1110, #1111 and more) and possible crashes (#1092)
* Portable OpenSSH-specific fixes:
Pass random seed during re-exec for each connection: speeds up
processing of new connections on platforms using the OpenSSH's
builtin entropy collector (ssh-rand-helper)
PAM fixes and improvements:
#1045 - Missing option for ignoring the /etc/nologin file
#1087 - Show PAM password expiry message from LDAP on login
#1028 - Forward final non-query conversations to client
#1126 - Prevent user from being forced to change an expired
password repeatedly on AIX in some PAM configurations.
#1045 - Do not check /etc/nologin when PAM is enabled, instead
allow PAM to handle it. Note that on platforms using
PAM, the pam_nologin module should be used in sshd's
session stack in order to maintain past behaviour
Portability-related fixes:
#989 - Fix multiplexing regress test on Solaris
#1097 - Cross-compile fixes.
#1096 - ssh-keygen broken on HPUX.
#1098 - $MAIL being set incorrectly for HPUX server login.
#1104 - Compile error on Tru64 Unix 4.0f
#1106 - Updated .spec file and startup for SuSE.
#1122 - Use _GNU_SOURCE define in favor of __USE_GNU, fixing
compilation problems on glibc 2.4
Thanks to everyone who has contributed patches, reported bugs or test
releases.
Checksums:
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.
OpenSSH 4.2 was released on 2005-09-01. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
We would like to thank the OpenSSH community for their continued
support of the project, especially those who contributed source,
reported bugs, tested snapshots and purchased T-shirts or posters.
T-shirt, poster and CD sales directly support the project. Pictures
and more information can be found at:
http://www.openbsd.org/tshirts.html and
http://www.openbsd.org/orders.html
For international orders use http://https.openbsd.org/cgi-bin/order
and for European orders, use http://https.openbsd.org/cgi-bin/order.eu
Changes since OpenSSH 4.1:
SECURITY: Fix a bug introduced in OpenSSH 4.0 that caused
GatewayPorts to be incorrectly activated for dynamic ("-D") port
forwardings when no listen address was explicitly specified.
SECURITY: sshd in OpenSSH versions prior to 4.2 allow GSSAPI
credentials to be delegated to users who log in with methods
other than GSSAPI authentication (e.g. public key) when the
client requests it. This behaviour has been changed in OpenSSH
4.2 to only delegate credentials to users who authenticate
using the GSSAPI method. This eliminates the risk of credentials
being inadvertently exposed to an untrusted user/host (though
users should not activate GSSAPIDelegateCredentials to begin
with when the remote user or host is untrusted)
Added a new compression method that delays the start of zlib
compression until the user has been authenticated successfully.
The new method ("Compression delayed") is on by default in the
server. This eliminates the risk of any zlib vulnerability
leading to a compromise of the server from unauthenticated users.
NB. Older OpenSSH (<3.5) versions have a bug that will cause them
to refuse to connect to any server that does not offer compression
when the client has compression requested. Since the new "delayed"
server mode isn't supported by these older clients, they will
refuse to connect to a new server unless compression is disabled
(on the client end) or the original compression method is enabled
on the server ("Compression yes" in sshd_config)
Another round of proactive changes for signed vs unsigned integer
bugs has been completed, including changing the atomicio() API to
encourage safer programming. This work is ongoing.
Added support for the improved arcfour cipher modes from
draft-harris-ssh-arcfour-fixes-02. The improves the cipher's
resistance to a number of attacks by discarding early keystream
output.
Increase the default size of new RSA/DSA keys generated by
ssh-keygen from 1024 to 2048 bits.
Many bugfixes and improvements to connection multiplexing,
including:
Added ControlMaster=auto/autoask options to support opportunistic
multiplexing (see the ssh_config(5) manpage for details).
The client will now gracefully fallback to starting a new TCP
connection if it cannot connect to a specified multiplexing
control socket
Added %h (target hostname), %p (target port) and %r (remote
username) expansion sequences to ControlPath. Also allow
ControlPath=none to disable connection multiplexing.
Implemented support for X11 and agent forwarding over multiplexed
connections. Because of protocol limitations, the slave
connections inherit the master's DISPLAY and SSH_AUTH_SOCK rather
than distinctly forwarding their own.
Portable OpenSSH: Added support for long passwords (> 8-char) on
UnixWare 7.
The following bugs from http://bugzilla.mindrot.org/ were closed:
#471 - Misleading error message if /dev/tty perms wrong
#623 - Don't use $HOME in manpages
#829 - Don't allocate a tty if -n option is set
#1025 - Correctly handle disabled special character in ttymodes
#1033 - Fix compile-time warnings
#1046 - AIX 5.3 Garbage on Login
#1054 - Don't terminate connection on getpeername() failure
#1076 - GSSAPIDelegateCredentials issue mentioned above
Lots of other improvements and fixes. Please refer to the ChangeLog
for details
Thanks to everyone who has contributed patches, problem or test reports.
Checksums:
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Ben Lindstrom, Darren Tucker and Tim Rice.
OpenSSH 4.1 was released on 2005-05-26. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
We would like to thank the OpenSSH community for their continued
support to the project, especially those who contributed source and
bought T-shirts or posters.
We have a new design of T-shirt available, more info on
http://www.openbsd.org/tshirts.html#18
For international orders use http://https.openbsd.org/cgi-bin/order
and for European orders, use http://https.openbsd.org/cgi-bin/order.eu
Changes since OpenSSH 4.0:
* This is a bugfix release, no new features have been added. Some notable
fixes are:
Fix segfault when using forwardings configured in ssh_config(5) and
ClearAllForwardings (bugzilla #996)
Limit input buffer size for channels. A peer could send more data
than the buffer code was willing to accept. This would cause OpenSSH
to abort the connection (bugzilla #896)
* Several improvements to the regression tests
* Portable OpenSSH:
- OpenSSH will now always normalise IPv4 in IPv6 mapped addresses back to
IPv4 addresses. This means that IPv4 addresses in log messages on IPv6
enabled machines will no longer be prefixed by "::ffff:" and AllowUsers,
DenyUsers, AllowGroups, DenyGroups will match IPv4-style addresses only
for 4-in-6 mapped connections. This ensures a consistent representation
of IPv4 addresses regardless of whether or not the machine is IPv6
enabled.
* Other bugfixes, including bugzilla #950, #997, #998, #999, #1005, #1006,
#1024, and #1038
Changes since OpenSSH 3.9:
* ssh(1) now allows the optional specification of an address to bind to
in port forwarding connections (local, remote and dynamic). Please
refer to the documentation for the -L and -R options in the ssh(1)
manual page and the LocalForward and RemoteForward options in the
ssh_config(5) manpage. (Bugzilla #413)
* To control remote bindings while retaining backwards compatibility,
sshd(8)'s GatewayPorts option has been extended. To allow client
specified bind addresses for remote (-R) port forwardings, the server
must be configured with "GatewayPorts clientspecified".
* ssh(1) and ssh-keyscan(1) now support hashing of host names and
addresses added to known_hosts files, controlled by the ssh(1)
HashKnownHosts configuration directive. This option improves user
privacy by hiding which hosts have been visited. At present this
option is off by default, but may be turned on once it receives
sufficient testing.
* Added options for managing keys in known_hosts files to ssh-keygen(1),
including the ability to search for hosts by name, delete hosts by
name and convert an unhashed known_hosts file into one with hashed
names. These are particularly useful for managing known_hosts files
with hashed hostnames.
* Improve account and password expiry support in sshd(8). The server
will now warn in advance for both account and password expiry.
* sshd(8) will now log the source of connections denied by AllowUsers,
DenyUsers, AllowGroups and DenyGroups (Bugzilla #909)
* Added AddressFamily option to sshd(8) to allow global control over
IPv4/IPv6 usage. (Bugzilla #989)
* Improved sftp(1) client, including bugfixes and optimisations for the
``ls'' command and command history and editing support using libedit.
* Improved the handling of bad data in authorized_keys files,
eliminating fatal errors on corrupt or very large keys. (Bugzilla
#884)
* Improved connection multiplexing support in ssh(1). Several bugs
have been fixed and a new "command mode" has been added to allow the
control of a running multiplexing master connection, including
checking that it is up, determining its PID and asking it to exit.
* Have scp(1) and sftp(1) wait for the spawned ssh to exit before they
exit themselves. This prevents ssh from being unable to restore
terminal modes (not normally a problem on OpenBSD but common with
-Portable on POSIX platforms). (Bugzilla #950)
* Portable OpenSSH:
Add *EXPERIMENTAL* BSM audit support for Solaris systems
(Bugzilla #125)
Enable IPv6 on AIX where possible (see README.platform for
details), working around a misfeature of AIX's getnameinfo.
(Bugzilla #835)
Teach sshd(8) to write failed login records to btmp for
unsuccessful auth attempts. Currently this is only for password,
keyboard-interactive and challenge/response authentication methods
and only on Linux and HP-UX.
sshd(8) now sends output from failing PAM session modules to the
user before exiting, similar to the way /etc/nologin is handled
Store credentials from gssapi-with-mic authentication early enough
to be available to PAM session modules when privsep=yes.
Checksums:
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Ben Lindstrom, Darren Tucker and Tim Rice.
OpenSSH 4.0 was released on 2005-03-09. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
We would like to thank the OpenSSH community for their continued
support to the project, especially those who contributed source and
bought T-shirts or posters.
We have a new design of T-shirt available, more info on
http://www.openbsd.org/tshirts.html#18
For international orders use http://https.openbsd.org/cgi-bin/order
and for European orders, use http://https.openbsd.org/cgi-bin/order.eu
Changes since OpenSSH 3.9:
* ssh(1) now allows the optional specification of an address to bind to
in port forwarding connections (local, remote and dynamic). Please
refer to the documentation for the -L and -R options in the ssh(1)
manual page and the LocalForward and RemoteForward options in the
ssh_config(5) manpage. (Bugzilla #413)
* To control remote bindings while retaining backwards compatibility,
sshd(8)'s GatewayPorts option has been extended. To allow client
specified bind addresses for remote (-R) port forwardings, the server
must be configured with "GatewayPorts clientspecified".
* ssh(1) and ssh-keyscan(1) now support hashing of host names and
addresses added to known_hosts files, controlled by the ssh(1)
HashKnownHosts configuration directive. This option improves user
privacy by hiding which hosts have been visited. At present this
option is off by default, but may be turned on once it receives
sufficient testing.
* Added options for managing keys in known_hosts files to ssh-keygen(1),
including the ability to search for hosts by name, delete hosts by
name and convert an unhashed known_hosts file into one with hashed
names. These are particularly useful for managing known_hosts files
with hashed hostnames.
* Improve account and password expiry support in sshd(8). The server
will now warn in advance for both account and password expiry.
* sshd(8) will now log the source of connections denied by AllowUsers,
DenyUsers, AllowGroups and DenyGroups (Bugzilla #909)
* Added AddressFamily option to sshd(8) to allow global control over
IPv4/IPv6 usage. (Bugzilla #989)
* Improved sftp(1) client, including bugfixes and optimisations for the
``ls'' command and command history and editing support using libedit.
* Improved the handling of bad data in authorized_keys files,
eliminating fatal errors on corrupt or very large keys. (Bugzilla
#884)
* Improved connection multiplexing support in ssh(1). Several bugs
have been fixed and a new "command mode" has been added to allow the
control of a running multiplexing master connection, including
checking that it is up, determining its PID and asking it to exit.
* Have scp(1) and sftp(1) wait for the spawned ssh to exit before they
exit themselves. This prevents ssh from being unable to restore
terminal modes (not normally a problem on OpenBSD but common with
-Portable on POSIX platforms). (Bugzilla #950)
* Portable OpenSSH:
Add *EXPERIMENTAL* BSM audit support for Solaris systems
(Bugzilla #125)
Enable IPv6 on AIX where possible (see README.platform for
details), working around a misfeature of AIX's getnameinfo.
(Bugzilla #835)
Teach sshd(8) to write failed login records to btmp for
unsuccessful auth attempts. Currently this is only for password,
keyboard-interactive and challenge/response authentication methods
and only on Linux and HP-UX.
sshd(8) now sends output from failing PAM session modules to the
user before exiting, similar to the way /etc/nologin is handled
Store credentials from gssapi-with-mic authentication early enough
to be available to PAM session modules when privsep=yes.
Checksums:
- MD5 (openssh-4.0.tgz) = 7dbf15fe7c294672e8822127f50107d0
- MD5 (openssh-4.0p1.tar.gz) = 7b36f28fc16e1b7f4ba3c1dca191ac92
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Ben Lindstrom, Darren Tucker and Tim Rice.
OpenSSH 3.9 was released on 2004-08-18. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
We would like to thank the OpenSSH community for their continued
support to the project, especially those who contributed source and
bought T-shirts or posters.
We have a new design of T-shirt available, more info on
http://www.openbsd.org/tshirts.html#18
For international orders use http://https.openbsd.org/cgi-bin/order
and for European orders, use http://https.openbsd.org/cgi-bin/order.eu
Changes since OpenSSH 3.8:
* Added new "IdentitiesOnly" option to ssh(1), which specifies that it should
use keys specified in ssh_config, rather than any keys in ssh-agent(1)
* Make sshd(8) re-execute itself on accepting a new connection. This security
measure ensures that all execute-time randomisations are reapplied for each
connection rather than once, for the master process' lifetime. This includes
mmap and malloc mappings, shared library addressing, shared library mapping
order, ProPolice and StackGhost cookies on systems that support such things
* Add strict permission and ownership checks to programs reading ~/.ssh/config
NB ssh(1) will now exit instead of trying to process a config with poor
ownership or permissions
* Implemented the ability to pass selected environment variables between the
client and the server. See "AcceptEnv" in sshd_config(5) and "SendEnv" in
ssh_config(5) for details
* Added a "MaxAuthTries" option to sshd(8), allowing control over the maximum
number of authentication attempts permitted per connection
* Added support for cancellation of active remote port forwarding sessions.
This may be performed using the ~C escape character, see "Escape Characters"
in ssh(1) for details
* Many sftp(1) interface improvements, including greatly enhanced "ls" support
and the ability to cancel active transfers using SIGINT (^C)
* Implement session multiplexing: a single ssh(1) connection can now carry
multiple login/command/file transfer sessions. Refer to the "ControlMaster"
and "ControlPath" options in ssh_config(5) for more information
* The sftp-server has improved support for non-POSIX filesystems (e.g. FAT)
* Portable OpenSSH: Re-introduce support for PAM password authentication, in
addition to the keyboard-interactive driver. PAM password authentication
is less flexible, and doesn't support pre-authentication password expiry but
runs in-process so Kerberos tokens, etc are retained
* Improved and more extensive regression tests
* Many bugfixes and small improvements
Checksums:
- MD5 (openssh-3.9.tgz) = 93f48bfcc1560895ae53de6bfc41689b
- MD5 (openssh-3.9p1.tar.gz) = 8e1774d0b52aff08f817f3987442a16e
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Ben Lindstrom, Darren Tucker and Tim Rice.
OpenSSH 3.8.1p1 was released on 2004-04-19. It is available from
the mirrors listed at https://www.openssh.com/.
This release is a bug-fix release for the portable version. There are
no feature additions and no corresponding OpenBSD-only release.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
We would like to thank the OpenSSH community for their continued
support to the project, especially those who contributed source, help
with testing and have bought T-shirts or posters.
We have a new design of T-shirt available, more info on
http://www.openbsd.org/tshirts.html#18
For international orders use http://https.openbsd.org/cgi-bin/order
and for European orders, use http://https.openbsd.org/cgi-bin/order.eu
Bugs fixed since OpenSSH 3.8p1:
Bug #673 - Fix compilation on NetBSD with S/Key enabled
Bug #748 - Detect and workaround broken name resolution on HP-UX
Bug #802 - Fix linking on Tru64 when compiled with SIA support
Bug #808 - Fix PAM crash on expired password when not authenticated using
pam/kbdint mechanism
Bug #810 - Fix erroneous clearing of TZ environment variable
Bug #811 - Improve locked password detection across Linux variants
Bug #820 - Fix utmp corruption on Irix
Bug #825 - Fix disconnection problem when using IPv4-in-IPv6 mapped
addresses on Solaris.
Fix compilation on OS X systems with Kerberos/GSSAPI
Many more minor fixes, please refer to the ChangeLog file for details
Checksums:
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Ben Lindstrom, Darren Tucker and Tim Rice.
3.8.1p1 is a Portable-only release, there is no corresponding 3.8.1 release.
See http://www.openssh.com/txt/release-3.8.1p1 for the Portable release notes.
OpenSSH 3.8 was released on 2004-02-24. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
We would like to thank the OpenSSH community for their continued
support to the project, especially those who contributed source and
bought T-shirts or posters.
We have a new design of T-shirt available, more info on
http://www.openbsd.org/tshirts.html#18
For international orders use http://https.openbsd.org/cgi-bin/order
and for European orders, use http://https.openbsd.org/cgi-bin/order.eu
Changes since OpenSSH 3.7.1:
* sshd(8) now supports forced changes of expired passwords via
/usr/bin/passwd or keyboard-interactive authentication.
Note for AIX: sshd will now deny password access to accounts with
passwords expired longer than their maxexpired attribute. For
details, see the AIX section in README.platform.
* ssh(1) now uses untrusted cookies for X11-Forwarding.
Some X11 applications might need full access to the X11 server,
see ForwardX11Trusted in ssh(1) and xauth(1) for more information.
* ssh(1) now supports sending application layer
keep-alive messages to the server. See ServerAliveInterval
in ssh(1) for more information.
* Improved sftp(1) batch file support.
* New KerberosGetAFSToken option for sshd(8).
* Updated /etc/moduli file and improved performance for
protocol version 2.
* Support for host keys in DNS (draft-ietf-secsh-dns-xx.txt).
Please see README.dns in the source distribution for details.
* Fix a number of memory leaks.
* The experimental "gssapi" support has been replaced with
the "gssapi-with-mic" to fix possible MITM attacks.
The two versions are not compatible.
Checksums:
- MD5 (openssh-3.8.tgz) = 7d5590a333d8f8aa1fa6f19e24938700
- MD5 (openssh-3.8p1.tar.gz) = 7861a4c0841ab69a6eec5c747daff6fb
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Ben Lindstrom, Darren Tucker and Tim Rice.
Portable OpenSSH 3.7.1p2 was released on 2003-09-23. It will be available
from the mirrors listed at http://www.openssh.com/portable.html shortly.
Please note that this is a release to address issues in the portable
version only. The items mentioned below do not affect the OpenBSD
version.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
We would like to thank the OpenSSH community for their continued
support to the project, especially those who contributed source and
bought T-shirts or posters.
We have a new design of T-shirt available, more info on
http://www.openbsd.org/tshirts.html#18
For international orders use http://https.openbsd.org/cgi-bin/order
and for European orders, use http://https.openbsd.org/cgi-bin/order.eu
Security Changes:
Portable OpenSSH version 3.7p1 and 3.7.1p1 contain multiple
vulnerabilities in the new PAM authentication code. At least one of
these bugs is remotely exploitable (under a non-standard
configuration, with privsep disabled).
OpenSSH 3.7.1p2 fixes these bugs. Please note that these bugs do not
exist in OpenBSD's releases of OpenSSH.
Changes since OpenSSH 3.7.1p1:
* This release disables PAM by default. To enable it, set "UsePAM yes" in
sshd_config. Due to complexity, inconsistencies in the specification and
differences between vendors' PAM implementations we recommend that PAM
be left disabled in sshd_config unless there is a need for its use.
Sites using only public key or simple password authentication usually
have little need to enable PAM support.
* This release now requires zlib 1.1.4 to build correctly. Previous
versions have security problems.
* Fix compilation for versions of OpenSSL before 0.9.6. Some cipher modes
are not supported for older OpenSSL versions.
* Fix compilation problems on systems with a missing or lacking inet_ntoa()
function.
* Workaround problems related to unimplemented or broken setresuid/setreuid
functions on several platforms.
* Fix compilation on older OpenBSD systems.
* Fix handling of password-less authentication (PermitEmptyPasswords=yes)
that has not worked since the 3.7p1 release.
Checksums:
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Ben Lindstrom, Darren Tucker and Tim Rice.
OpenSSH 3.7.1 was released on 2004-02-25. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
We would like to thank the OpenSSH community for their continued
support to the project, especially those who contributed source and
bought T-shirts or posters.
We have a new design of T-shirt available, more info on
http://www.openbsd.org/tshirts.html#18
For international orders use https://https.openbsd.org/cgi-bin/order
and for European orders, use https://https.openbsd.org/cgi-bin/order.eu
Security Changes:
All versions of OpenSSH's sshd prior to 3.7.1 contain buffer
management errors. It is uncertain whether these errors are
potentially exploitable, however, we prefer to see bugs
fixed proactively.
OpenSSH 3.7 fixed one of these bugs.
OpenSSH 3.7.1 fixes more similar bugs.
Changes since OpenSSH 3.6.1:
* The entire OpenSSH code-base has undergone a license review. As
a result, all non-ssh1.x code is under a BSD-style license with no
advertising requirement. Please refer to README in the source
distribution for the exact license terms.
* Rhosts authentication has been removed in ssh(1) and sshd(8).
* Changes in Kerberos support:
- KerberosV password support now uses a file cache instead of
a memory cache.
- KerberosIV and AFS support has been removed.
- KerberosV support has been removed from SSH protocol 1.
- KerberosV password authentication support remains for SSH
protocols 1 and 2.
- This release contains some GSSAPI user authentication support
to replace legacy KerberosV authentication support. At present
this code is still considered experimental and SHOULD NOT BE
USED.
* Changed order that keys are tried in public key authentication.
The ssh(1) client tries the keys in the following order:
1. [ssh-agent(1)](https://man.openbsd.org/ssh-agent.1) keys that are found in the [ssh\_config(5)](https://man.openbsd.org/ssh_config.5) file
2. remaining [ssh-agent(1)](https://man.openbsd.org/ssh-agent.1) keys
3. keys that are only listed in the [ssh\_config(5)](https://man.openbsd.org/ssh_config.5) file
This helps when an ssh-agent(1) has many keys, where the sshd(8)
server might close the connection before the correct key is tried.
* SOCKS5 support has been added to the dynamic forwarding mode
in ssh(1).
* Removed implementation barriers to operation of SSH over SCTP.
* sftp(1) client can now transfer files with quote characters in
their filenames.
* Replaced sshd(8)'s VerifyReverseMapping with UseDNS option.
When UseDNS option is on, reverse hostname lookups are always
performed.
* Fix a number of memory leaks.
* Support for sending tty BREAK over SSH protocol 2.
* Workaround for other vendor bugs in KEX guess handling.
* Support for generating KEX-GEX groups (/etc/moduli) in ssh-keygen(1).
* Automatic re-keying based on amount of data sent over connection.
* New AddressFamily option on client to select protocol to use (IPv4
or IPv6).
* Experimental support for the "aes128-ctr", "aes192-ctr", and
"aes256-ctr" ciphers for SSH protocol 2.
* Experimental support for host keys in DNS (draft-ietf-secsh-dns-xx.txt).
Please see README.dns in the source distribution for details.
* Portable OpenSSH:
- Replace PAM password authentication kludge with a more correct
PAM challenge-response module from FreeBSD.
- PAM support may now be enabled/disabled at runtime using the
UsePAM directive.
- Many improvements to the OpenSC smartcard support.
- Regression tests now work with portable OpenSSH.
Please refer to regress/README.regress in the source distribution.
- On platforms that support it, portable OpenSSH now honors the
UMASK, PATH and SUPATH attributes set in /etc/default/login.
- Deny access to locked accounts, regardless of authentication
method in use.
Checksums:
- MD5 (openssh-3.7.1.tgz) = 3d2f1644d6a3d3267e5e2421f1385129
- MD5 (openssh-3.7.1p1.tar.gz) = f54e574e606c08ef63ebb1ab2f7689dc
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Ben Lindstrom, Darren Tucker and Tim Rice.
OpenSSH 3.7 was released on 2003-09-16. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
We would like to thank the OpenSSH community for their continued
support to the project, especially those who contributed source and
bought T-shirts or posters.
We have a new design of T-shirt available, more info on
http://www.openbsd.org/tshirts.html#18
For international orders use http://https.openbsd.org/cgi-bin/order
and for European orders, use http://https.openbsd.org/cgi-bin/order.eu
Security Changes:
All versions of OpenSSH's sshd prior to 3.7 contain a buffer
management error. It is uncertain whether this error is
potentially exploitable, however, we prefer to see bugs
fixed proactively.
OpenSSH 3.7 fixes this bug.
Changes since OpenSSH 3.6.1:
* The entire OpenSSH code-base has undergone a license review. As
a result, all non-ssh1.x code is under a BSD-style license with no
advertising requirement. Please refer to README in the source
distribution for the exact license terms.
* Rhosts authentication has been removed in ssh(1) and sshd(8).
* Changes in Kerberos support:
- KerberosV password support now uses a file cache instead of
a memory cache.
- KerberosIV and AFS support has been removed.
- KerberosV support has been removed from SSH protocol 1.
- KerberosV password authentication support remains for SSH
protocols 1 and 2.
- This release contains some GSSAPI user authentication support
to replace legacy KerberosV authentication support. At present
this code is still considered experimental and SHOULD NOT BE
USED.
* Changed order that keys are tried in public key authentication.
The ssh(1) client tries the keys in the following order:
1. [ssh-agent(1)](https://man.openbsd.org/ssh-agent.1) keys that are found in the [ssh\_config(5)](https://man.openbsd.org/ssh_config.5) file
2. remaining [ssh-agent(1)](https://man.openbsd.org/ssh-agent.1) keys
3. keys that are only listed in the [ssh\_config(5)](https://man.openbsd.org/ssh_config.5) file
This helps when an ssh-agent(1) has many keys, where the sshd(8)
server might close the connection before the correct key is tried.
* SOCKS5 support has been added to the dynamic forwarding mode
in ssh(1).
* Removed implementation barriers to operation of SSH over SCTP.
* sftp(1) client can now transfer files with quote characters in
their filenames.
* Replaced sshd(8)'s VerifyReverseMapping with UseDNS option.
When UseDNS option is on, reverse hostname lookups are always
performed.
* Fix a number of memory leaks.
* Support for sending tty BREAK over SSH protocol 2.
* Workaround for other vendor bugs in KEX guess handling.
* Support for generating KEX-GEX groups (/etc/moduli) in ssh-keygen(1).
* Automatic re-keying based on amount of data sent over connection.
* New AddressFamily option on client to select protocol to use (IPv4
or IPv6).
* Experimental support for the "aes128-ctr", "aes192-ctr", and
"aes256-ctr" ciphers for SSH protocol 2.
* Experimental support for host keys in DNS (draft-ietf-secsh-dns-xx.txt).
Please see README.dns in the source distribution for details.
* Portable OpenSSH:
- Replace PAM password authentication kludge with a more correct
PAM challenge-response module from FreeBSD.
- PAM support may now be enabled/disabled at runtime using the
UsePAM directive.
- Many improvements to the OpenSC smartcard support.
- Regression tests now work with portable OpenSSH.
Please refer to regress/README.regress in the source distribution.
- On platforms that support it, portable OpenSSH now honors the
UMASK, PATH and SUPATH attributes set in /etc/default/login.
- Deny access to locked accounts, regardless of authentication
method in use.
Checksums:
- MD5 (openssh-3.7.tgz) = 86864ecc276c5f75b06d4872a553fa70
- MD5 (openssh-3.7p1.tar.gz) = 77662801ba2a9cadc0ac10054bc6cb37
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Ben Lindstrom, Darren Tucker and Tim Rice.
OpenSSH 3.6.1p2 was released on 2003-04-30. It is available from the
mirrors listed at https://www.openssh.com/.This is a release
of the Portable version only.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
We would like to thank the OpenSSH community for their continued
support and encouragement.
Changes since OpenSSH 3.6.1p1:
* Security: corrected linking problem on AIX/gcc. AIX users are
advised to upgrade immediately. For details, please refer to
separate advisory (aixgcc.adv).
* Corrected build problems on Irix
* Corrected build problem when building with AFS support
* Merged some changes from Openwall Linux
Checksums:
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller and Ben Lindstrom.
OpenSSH 3.6.1 was released on 2003-04-01. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
We would like to thank the OpenSSH community for their continued
support to the project, especially those who contributed source and
bought T-shirts or posters.
We have a new design of T-shirt available, more info on
http://www.openbsd.org/tshirts.html#18
For international orders use http://https.openbsd.org/cgi-bin/order
and for European orders, use http://https.openbsd.org/cgi-bin/order.eu
Changes since OpenSSH 3.6:
* The 'kex guesses' bugfix from OpenSSH 3.6 triggers a bug
in a few other SSH v2 implementations and causes connections to
stall. OpenSSH 3.6.1 disables this bugfix when interoperating
with these implementations.
Changes between OpenSSH 3.5 and OpenSSH 3.6:
* RSA blinding is now used by ssh(1), sshd(8) and ssh-agent(1).
in order to avoid potential timing attacks against the RSA keys.
Older versions of OpenSSH have been using RSA blinding in
ssh-keysign(1) only.
Please note that there is no evidence that the SSH protocol is
vulnerable to the OpenSSL/TLS timing attack described in
http://crypto.stanford.edu/~dabo/papers/ssl-timing.pdf
* ssh-agent(1) optionally requires user confirmation if a key gets
used, see '-c' in ssh-add(1).
* sshd(8) now handles PermitRootLogin correctly when UsePrivilegeSeparation
is enabled.
* sshd(8) now removes X11 cookies when a session gets closed.
* ssh-keysign(8) is disabled by default and only enabled if the
new EnableSSHKeysign option is set in the global ssh_config(5)
file.
* ssh(1) and sshd(8) now handle 'kex guesses' correctly (key exchange
guesses).
* ssh(1) no longer overwrites SIG_IGN. This matches behaviour from
rsh(1) and is used by backup tools.
* setting ProxyCommand to 'none' disables the proxy feature, see
ssh_config(5).
* scp(1) supports add -1 and -2.
* scp(1) supports bandwidth limiting.
* sftp(1) displays a progressmeter.
* sftp(1) has improved error handling for scripting.
Checksums:
- MD5 (openssh-3.6.1p1.tar.gz) = d4c2c88b883f097fe88e327cbb4b2e2a
- MD5 (openssh-3.6.1.tgz) = aa2acd2be17dc3fd514a1e09336aab51
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller and Ben Lindstrom.
OpenSSH 3.6 was released on 2003-03-31. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
We would like to thank the OpenSSH community for their continued
support to the project, especially those who contributed source and
bought T-shirts or posters.
We have a new design of T-shirt available, more info on
http://www.openbsd.org/tshirts.html#18
For international orders use http://https.openbsd.org/cgi-bin/order
and for European orders, use http://https.openbsd.org/cgi-bin/order.eu
Changes since OpenSSH 3.5:
* RSA blinding is now used by ssh(1), sshd(8) and ssh-agent(1).
in order to avoid potential timing attacks against the RSA keys.
Older versions of OpenSSH have been using RSA blinding in
ssh-keysign(1) only.
Please note that there is no evidence that the SSH protocol is
vulnerable to the OpenSSL/TLS timing attack described in
http://crypto.stanford.edu/~dabo/papers/ssl-timing.pdf
* ssh-agent(1) optionally requires user confirmation if a key gets
used, see '-c' in ssh-add(1).
* sshd(8) now handles PermitRootLogin correctly when UsePrivilegeSeparation
is enabled.
* sshd(8) now removes X11 cookies when a session gets closed.
* ssh-keysign(8) is disabled by default and only enabled if the
new EnableSSHKeysign option is set in the global ssh_config(5)
file.
* ssh(1) and sshd(8) now handle 'kex guesses' correctly (key exchange
guesses).
* ssh(1) no longer overwrites SIG_IGN. This matches behaviour from
rsh(1) and is used by backup tools.
* setting ProxyCommand to 'none' disables the proxy feature, see
ssh_config(5).
* scp(1) supports add -1 and -2.
* scp(1) supports bandwidth limiting.
* sftp(1) displays a progressmeter.
* sftp(1) has improved error handling for scripting.
Checksums:
- MD5 (openssh-3.6p1.tar.gz) = 72ef1134d521cb6926c99256dad17fe0
- MD5 (openssh-3.6.tgz) = 758822b888c5c3f83a98045aef904254
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller and Ben Lindstrom.
OpenSSH 3.5 was released on 2002-10-15. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
We would like to thank the OpenSSH community for their continued
support and encouragement.
Changes since OpenSSH 3.4:
* Improved support for Privilege Separation (Portability, Kerberos,
PermitRootLogin handling).
* ssh(1) prints out all known host keys for a host if it receives an
unknown host key of a different type.
* Fixed AES/Rijndael EVP integration for OpenSSL < 0.9.7 (caused
problems with bounds checking patches for gcc).
* ssh-keysign(8) is disabled by default and only enabled if the
HostbasedAuthentication option is enabled in the global ssh_config(5)
file.
* ssh-keysign(8) uses RSA blinding in order to avoid timing attacks
against the RSA host key.
* A use-after-free bug was fixed in ssh-keysign(8). This bug
broke hostbased authentication on several platforms.
* ssh-agent(1) is now installed setgid in order to avoid ptrace(2)
attacks.
* ssh-agent(1) now restricts the access with getpeereid(2) (or
equivalent, where available).
* sshd(8) no longer uses the ASN.1 parsing code from libcrypto when
verifying RSA signatures.
* sshd(8) now sets the SSH_CONNECTION environment variable.
* Enhanced "ls" support for the sftp(1) client, including globbing and
detailed listings.
* ssh(1) now always falls back to uncompressed sessions, if the
server does not support compression.
* The default behavior of sshd(8) with regard to user settable
environ variables has changed: the new option PermitUserEnvironment
is disabled by default, see sshd_config(5).
* The default value for LoginGraceTime has been changed from 600 to 120
seconds, see sshd_config(5).
* Removed erroneous SO_LINGER handling.
Checksums:
- MD5 (openssh-3.5p1.tar.gz) = 42bd78508d208b55843c84dd54dea848
- MD5 (openssh-3.5.tgz) = 79fc225dbe0fe71ebb6910f449101d23
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller and Ben Lindstrom.
OpenSSH 3.4 was released on 2002-06-26. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
We would like to thank the OpenSSH community for their continued
support and encouragement.
Changes since OpenSSH 3.3:
Security Changes:
All versions of OpenSSH's sshd between 2.9.9 and 3.3
contain an input validation error that can result in
an integer overflow and privilege escalation.
OpenSSH 3.4 fixes this bug.
In addition, OpenSSH 3.4 adds many checks to detect
invalid input and mitigate resource exhaustion attacks.
OpenSSH 3.2 and later prevent privilege escalation
if UsePrivilegeSeparation is enabled in sshd_config.
OpenSSH 3.3 enables UsePrivilegeSeparation by
default.
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller and Ben Lindstrom.
OpenSSH 3.3 was released on 2002-06-21. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
We would like to thank the OpenSSH community for their continued
support and encouragement.
Changes since OpenSSH 3.2.3:
Security Changes:
improved support for privilege separation:
privilege separation is now enabled by default
See UsePrivilegeSeparation in sshd_config(5)
and http://www.citi.umich.edu/u/provos/ssh/privsep.html for more
information.
ssh no longer needs to be installed setuid root for protocol
version 2 hostbased authentication, see ssh-keysign(8).
protocol version 1 rhosts-rsa authentication still requires privileges
and is not recommended.
Other Changes:
- documentation for the client and server configuration options have
been moved to ssh_config(5) and sshd_config(5).
- the server now supports the Compression option, see sshd_config(5).
- the client options RhostsRSAAuthentication and RhostsAuthentication now
default to no, see ssh_config(5).
- the client options FallBackToRsh and UseRsh are deprecated.
- ssh-agent now supports locking and timeouts for keys, see ssh-add(1).
- ssh-agent can now bind to unix-domain sockets given on the command line,
see ssh-agent(1).
- fixes problems with valid RSA signatures from putty clients.
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller and Ben Lindstrom.
OpenSSH 3.2.3 was released on 2002-05-23. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
We would like to thank the OpenSSH community for their continued
support and encouragement.
Changes since OpenSSH 3.2.2:
This release fixes several problems in OpenSSH 3.2.2:
- a defect in the BSD\_AUTH access control handling for
OpenBSD and BSD/OS systems:
Under certain conditions, on systems using YP with netgroups
in the password database, it is possible that sshd does ACL
checks for the requested user name but uses the password
database entry of a different user for authentication. This
means that denied users might authenticate successfully while
permitted users could be locked out (OpenBSD PR 2659).
- login/tty problems on Solaris (bug #245)
- build problems on Cygwin systems
Changes between OpenSSH 3.1 and OpenSSH 3.2.2:
Security Changes:
- fixed buffer overflow in Kerberos/AFS token passing
- fixed overflow in Kerberos client code
- sshd no longer auto-enables Kerberos/AFS
- experimental support for privilege separation,
see UsePrivilegeSeparation in sshd(8) and
http://www.citi.umich.edu/u/provos/ssh/privsep.html
for more information.
- only accept RSA keys of size SSH_RSA_MINIMUM_MODULUS_SIZE (768) or larger
Other Changes:
- improved smartcard support (including support for OpenSC,
see www.opensc.org)
- improved Kerberos support (including support for MIT-Kerberos V)
- fixed stderr handling in protocol v2
- client reports failure if -R style TCP forwarding fails in protocol v2
- support configuration of TCP forwarding during interactive sessions (~C)
- improved support for older sftp servers
- improved support for importing old DSA keys (from ssh.com software).
- client side support for PASSWD_CHANGEREQ in protocol v2
- fixed waitpid race conditions
- record correct lastlogin time
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller and Ben Lindstrom.
OpenSSH 3.2.2 was released on 2002-05-16. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
We would like to thank the OpenSSH community for their continued
support and encouragement.
Security Changes:
- fixed buffer overflow in Kerberos/AFS token passing
- fixed overflow in Kerberos client code
- sshd no longer auto-enables Kerberos/AFS
- experimental support for privilege separation,
see UsePrivilegeSeparation in sshd(8) and
http://www.citi.umich.edu/u/provos/ssh/privsep.html
for more information.
- only accept RSA keys of size SSH_RSA_MINIMUM_MODULUS_SIZE (768) or larger
Other Changes:
- improved smartcard support (including support for OpenSC, see www.opensc.org)
- improved Kerberos support (including support for MIT-Kerberos V)
- fixed stderr handling in protocol v2
- client reports failure if -R style TCP forwarding fails in protocol v2
- support configuration of TCP forwarding during interactive sessions (~C)
- improved support for older sftp servers
- improved support for importing old DSA keys (from ssh.com software).
- client side support for PASSWD_CHANGEREQ in protocol v2
- fixed waitpid race conditions
- record correct lastlogin time
Reporting Bugs:
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller and Ben Lindstrom.
OpenSSH 3.1 was released on 2004-04-09. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
We would like to thank the OpenSSH community for their continued
support and encouragement.
Important Changes:
- /etc/ssh/ now default directory for keys and configuration files
- ssh-keygen no longer defaults to a specific key type (rsa1);
use ssh-keygen -t {rsa,dsa,rsa1}
- sshd x11 forwarding listens on localhost by default;
see sshd X11UseLocalhost option to revert to prior behaviour
if your older X11 clients do not function with this configuration
Other Changes:
- ssh ~& escape char functions now for both protocol versions
- sshd ReverseMappingCheck option changed to VerifyReverseMapping
to clarify its function; ReverseMappingCheck can still be used
- public key fingerprint is now logged with LogLevel=VERBOSE
- reason logged for disallowed logins (e.g., no shell, etc.)
- more robust error handling for x11 forwarding
- improved packet/window size handling in ssh2
- use of regex(3) has been removed
- fix SIGCHLD races in sshd (seen on Solaris)
- sshd -o option added
- sftp -B -R -P options added
- ssh-add now adds all 3 default keys
- ssh-keyscan bug fixes
- ssh-askpass for hostkey dialog
- fix fd leak in sshd on SIGHUP
- TCP_NODELAY set on X11 and TCP forwarding endpoints
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller and Ben Lindstrom.
OpenSSH 3.0.2 was released on 2002-12-04. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
We would like to thank the OpenSSH community for their continued
support and encouragement.
Important Changes:
This release fixes a vulnerability in the UseLogin option
of OpenSSH. This option is not enabled in the default
installation of OpenSSH.
However, if UseLogin is enabled by the administrator, all
versions of OpenSSH prior to 3.0.2 may be vulnerable to
local attacks.
The vulnerability allows local users to pass environment
variables (e.g. LD\_PRELOAD) to the login process. The login
process is run with the same privilege as sshd (usually
with root privilege).
Do not enable UseLogin on your machines or disable UseLogin
again in /etc/sshd\_config:
UseLogin no
We also have received many reports about attacks against the crc32
bug. This bug has been fixed about 12 months ago in OpenSSH 2.3.0.
However, these attacks cause non-vulnerable daemons to chew a lot
of cpu since the crc32 attack sends a tremendously large amount of
data which must be processed.
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller and Ben Lindstrom.
The following patch fixes the UseLogin vulnerability in OpenSSH 3.0.1 and
earlier releases.
--- session.c 11 Oct 2001 13:45:21 -0000 1.108
+++ session.c 1 Dec 2001 22:14:39 -0000
@@ -875,6 +875,7 @@
child_set_env(&env, &envsize, "TZ", getenv("TZ"));
/\* Set custom environment options from RSA authentication. \*/
- if (!options.use_login)
while (custom_environment) {
struct envstring *ce = custom_environment;
char *s = ce->s;
OpenSSH 3.0.1 was released on 2001-11-19. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
We would like to thank the OpenSSH community for their continued
support and encouragement.
Important Changes:
A security hole that may allow an attacker to authenticate
if -- and only if -- the administrator has enabled KerberosV.
By default, OpenSSH KerberosV support only becomes active
after KerberosV has been properly configured.
An excessive memory clearing bug (which we believe to be
unexploitable) also exists, but since this may cause daemon
crashes, we are providing a fix as well.
Various other non-critical fixes (~& support and more).
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller and Ben Lindstrom.
OpenSSH 3.0 was released on 2001-11-06. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
This release contains many portability bug-fixes (listed in the
ChangeLog) as well as several new features (listed below).
We would like to thank the OpenSSH community for their continued
support and encouragement.
Important Changes:
SSH protocol v2 is now the default protocol version
use the 'Protocol' option from ssh(1) and sshd(8) if
you need to change this.
The files
/etc/ssh_known_hosts2
~/.ssh/known_hosts2
~/.ssh/authorized_keys2
are now obsolete, you can use
/etc/ssh_known_hosts
~/.ssh/known_hosts
~/.ssh/authorized_keys
For backward compatibility ~/.ssh/authorized_keys2 will still used for
authentication and hostkeys are still read from the known_hosts2.
However, those deprecated files are considered 'readonly'. Future
releases are likely not to read these files.
The CheckMail option in sshd_config is deprecated, as sshd(8) no longer
checks for new mail.
X11 cookies are now stored in $HOME.
New Features:
Smartcard support in the ssh client and agent based on work by
University of Michigan CITI (http://www.citi.umich.edu/projects/smartcard/).
support for Rekeying in protocol version 2
improved Kerberos support in protocol v1 (KerbIV and KerbV)
backward compatibility with older commercial SSH versions >= 2.0.10
getopt(3) is now used by all programs
dynamic forwarding (use ssh(1) as your socks server)
ClearAllForwardings in ssh(1)
ssh(1) now checks the hostkey for localhost (NoHostAuthenticationForLocalhost yes/no).
-F option in ssh(1)
ssh(1) now has a '-b bindaddress' option
scp(1) allows "scp /file localhost:/file"
The AuthorizedKeysFile option allows specification of alternative
files that contain the public keys that can be used for user authentication
(e.g. /etc/ssh_keys/%u, see sshd(8))
extended AllowUsers user@host syntax in sshd(8)
improved challenge-response support (especially for systems supporting BSD_AUTH)
sshd(8) can specify time args as 1h, 2h30s etc.
sshd(8) transmits the correct exit status for remote execution with protocol version 2.
ssh-keygen(1) can import private RSA/DSA keys generated with the commercial version
ssh-keyscan(1) supports protocol version 2
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller and Ben Lindstrom.
Portable OpenSSH 2.9p2 has just been uploaded and shall be making its
way to the mirrors listed at http://www.openssh.com/portable.html
shortly.
This release fixes the "cookies" file deletion problem reported on
BUGTRAQ as well as a few other minor (non-security) bugs. No new
features have been added in this release.
Regards,
Damien Miller
OpenSSH 2.9.9 has just been uploaded. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH 2.9.9 fixes a weakness in the key file option handling,
including source IP based access control.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
This release contains many portability bug-fixes (listed in the
ChangeLog) as well as several new features (listed below).
We would like to thank the OpenSSH community for their continued
support and encouragement.
Security Notes:
This release fixes weakness in the source IP based access control
for SSH protocol v2 public key authentication:
Versions of OpenSSH between 2.5 and 2.9.9 are
affected if they use the 'from=' key file option in
combination with both RSA and DSA keys in
~/.ssh/authorized\_keys2.
Depending on the order of the user keys in
~/.ssh/authorized\_keys2 sshd might fail to apply the
source IP based access control restriction (e.g.
from="10.0.0.1") to the correct key:
If a source IP restricted key (e.g. DSA key) is
immediately followed by a key of a different type
(e.g. RSA key), then key options for the second key
are applied to both keys, which includes 'from='.
This means that users can circumvent the system policy
and login from disallowed source IP addresses.
Important Changes:
OpenSSH 2.9.9 might have upgrade issues introduced by the long time
between releases, which may affect people in unforeseen ways:
The files
/etc/ssh_known_hosts2
~/.ssh/known_hosts2
~/.ssh/authorized_keys2
are now obsolete, you can use
/etc/ssh_known_hosts
~/.ssh/known_hosts
~/.ssh/authorized_keys
For backward compatibility ~/.ssh/authorized_keys2 is still used for
authentication and hostkeys are still read from the known_hosts2.
However, old files are considered 'readonly'. Future releases are
likely to not read these files.
The CheckMail option in sshd_config is deprecated, sshd no longer
checks for new mail.
X11 cookies are stored in $HOME
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller and Ben Lindstrom.
OpenSSH 2.9 has just been uploaded. It is available from the
mirrors listed at https://www.openssh.com/.
OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0
implementation and includes sftp client and server support.
This release contains many portability bug-fixes (listed in the
ChangeLog) as well as several new features (listed below).
We would like to thank the OpenSSH community for their continued
support and encouragement.
Important Changes:
WARNING: SSH protocol v2 is now the default protocol version
use the 'Protocol' option from [ssh(1)](https://man.openbsd.org/ssh.1) and [sshd(8)](https://man.openbsd.org/sshd.8) if
you want to change this.
SSH protocol v2 implementation adds support for:
HostbasedAuthentication, similar to RhostsRSA in SSH protocol
v1
Rekeying (negotiate new encryption keys for the current SSH
session, try ~R in interactive SSH sessions)
updated DH group exchange:
draft-ietf-secsh-dh-group-exchange-01.txt
client option HostKeyAlgorithms
server options ClientAliveInterval and ClientAliveCountMax
tty mode passing
general:
gid swapping in sshd (fixes access to /home/group/user based
directory structures)
Dan Kaminsky <dankamin@cisco.com> contributed an experimental
SOCKS4 proxy to the ssh client (yes, client not the server).
Use 'ssh -D 1080 server' if you want to try this out.
server option PrintLastLog
improvements for scp > 2GB
improved ListenAddress option.
You can now use ListenAddress host:port
improved interoperability (bug detection for older implementations)
improved documentation
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller and Ben Lindstrom.
Portable OpenSSH 2.5.2p2 is now available from the mirror sites
listed at http://www.openssh.com/portable.html
Security related changes:
Improved countermeasure against "Passive Analysis of SSH
(Secure Shell) Traffic"
http://openwall.com/advisories/OW-003-ssh-traffic-analysis.txt
The countermeasures introduced in earlier OpenSSH-2.5.x versions
caused interoperability problems with some other implementations.
Improved countermeasure against "SSH protocol 1.5 session
key recovery vulnerability"
[http://www.core-sdi.com/advisories/ssh1\_sessionkey\_recovery.htm](http://www.core-sdi.com/advisories/ssh1_sessionkey_recovery.htm)
New options:
permitopen authorized_keys option to restrict portforwarding.
PreferredAuthentications allows client to specify the order in which
authentication methods are tried.
Sftp:
sftp client supports globbing (get *, put *).
Support for sftp protocol v3 (draft-ietf-secsh-filexfer-01.txt).
Batch file (-b) support for automated transfers
Performance:
Speedup DH exchange. OpenSSH should now be significantly faster when
connecting use SSH protocol 2.
Preferred SSH protocol 2 cipher is AES with hmac-md5. AES offers
much faster throughput in a well scrutinised cipher.
Bugfixes:
stderr handling fixes in SSH protocol 2.
Improved interoperability.
Client:
The client no longer asks for the passphrase if the key
will not be accepted by the server (SSH2_MSG_USERAUTH_PK_OK)
Miscellaneous:
scp should now work for files > 2GB
ssh-keygen can now generate fingerprints in the "bubble babble"
format for exchanging fingerprints with SSH.COM's SSH protocol 2
implementation.
Portable version:
Better support for the PRNGd[1] entropy collection daemon. The
--with-egd-pool configure option has been deprecated in favour
of --with-prngd-socket and the new --with-prngd-port options.
The latter allows collection of entropy from a localhost
socket.
configure ensures that scp is in the $PATH set by the server
(unless a custom path is specified).
-d
[1] http://www.aet.tu-cottbus.de/personen/jaenicke/postfix_tls/prngd.html
Portable OpenSSH 2.5.1p2 has just been uploaded and will be making its
way to the mirror sites (http://www.openssh.com/portable.html)in due
course.
This release contains primarily bug-fixes over 2.5.1p1 but an upgrade is
recommended. Specific bug-fixes include:
- Fixed endianness issue causing failures when using Rijndael/AES cipher
- Fix PAM failures on Solaris and Linux
- Fix RPM spec file for Redhat systems
- Fixed several compatibility functions
- Fix entropy collection code for SCO3 and NeXTStep
- Many other minor fixes (see Changelog for details)
This release includes Mark Roth's mdoc2man.pl script which can be used
to fix up the manpages on systems that lack the full andoc set of
macros (e.g. Solaris). A future release of portable OpenSSH will automate
this scripts use for systems that require it.
-d
Portable OpenSSH 2.5.1p1 has just been uploaded. It will be available
from the mirrors listed at http://www.openssh.com/portable.html shortly.
OpenSSH is a 100% complete SSH 1.3 & 1.5 protocol implementation and
a 99% SSH 2 protocol implementation, including sftp client and server
support.
This release contains many portability bug-fixes (listed in the
ChangeLog) as well as several new features (listed below).
OpenSSH 2.5.0p1 was skipped because of interoperability issues with
ssh-1.2.18 => ssh-1.2.22.
We would like to thank the OpenSSH community for their continued support
and encouragement.
Important Changes:
Features added to the implementation of the SSH 2 protocol:
* agent forwarding
* support for -R forwarding
* RSA host and userkeys
* extended support for older SSH 2 protocol implementations
OpenSSH still lacks support for rekeying, so you have to turn off
rekeying if your server tries to force this feature.
The next release of OpenSSH will probably support rekeying.
Damien Miller contributed an interactive sftp client.
The sftp client works for both SSH protocol versions.
David Mazieres' ssh-keyscan has been added to the OpenSSH distribution.
Now there are three types of keys in OpenSSH:
RSA1 is used by the SSH 1 protocol only,
RSA and DSA keys are used by the SSH 2 protocol implementation.
You can generate RSA keys for use with SSH 2 protocol with:
$ ssh-keygen -t rsa -f /etc/ssh\_host\_rsa\_key
To use RSA or DSA keys in SSH 2 protocol, simply
add the public keys to the .ssh/authorised\_keys2 file.
IdentityFile2, HostDsaKey and DSAAuthentication are obsolete:
You can use multiple IdentityFile and HostKey options instead, e.g
HostKey /etc/ssh_host_key
HostKey /etc/ssh_host_dsa_key
HostKey /etc/ssh_host_rsa_key
in /etc/sshd_config
The option DSAAuthentication has been replaced by PubkeyAuthentication.
Fingerprinting works for all types of keys:
$ ssh-keygen -l -f $HOME/.ssh/{authorized\_keys,known\_hosts}{,2}
Important changes in the implementation of SSH 1 protocol:
The OpenSSH server does not require a privileged source port for
RhostsRsaAuthentication, since it adds no additional security.
Interoperation with SSH 1.4 protocol
New option HostKeyAlias
This option allows the user to record the host key under a
different name. This is useful for tunneling over
forwarded connections or if you run multiple sshd's on
different ports on the same machine.
Alternatively you can use the UserKnownHostsFile or
UserKnownHostsFile2 options to specify separate host key
files for the connection.
The ReverseMappingCheck is now optional in sshd_config.
If you combine this with the 'sshd -u0' option the server
will not do DNS lookups when a client connects.
Stricter Hostkey Checking
Option Change Summary:
a) New or changed:
ChallengeResponseAuthentication
MACs
PubkeyAuthentication
HostkeyAlias (Client only)
Banner (Server only)
ReverseMappingCheck (Server only)
PermitRootLogin {yes,without-password,forced-commands-only,no}
{Allow,Deny}Groups now support supplementary groups
sshd -D for monitoring scripts or inittab
ssh -t multiple -t force tty allocation
b) Obsolete:
DsaAuthentication (use PubkeyAuthentication instead)
HostDsaKey (use HostKey)
Identityfile2 (use Identityfile or -i)
SkeyAuthentication (use ChallengeResponseAuthentication)
TisAuthentication (use ChallengeResponseAuthentication)
OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller and Ben Lindstrom.
This is to announce the release of portable openssh-2.3.0p1. This
release includes many new features and bug fixes. This is a
recommended upgrade if you are using 2.2.0p1 or an older release.
Portable OpenSSH is available from one of the many mirrors listed at
http://www.openssh.com/portable.html
Some of the more notable features include:
Please refer to the ChangeLog for a full list of features and bugfixes.
Regards,
Damien Miller
Version 2.2.0p1 of portable OpenSSH has just been uploaded to the
master site and should be making its way to the mirrors in due
course.
http://www.openssh.com/portable.html
This release contains several new features and bugfixes relative to
the previous 2.1.1p4 release. In particular:
- DSA key support in ssh-agent. Please not that this will not
interop with ssh.com's ssh-agent (Markus Friedl)
- sshd now implements Random Early Drop connection rate limiting,
which can help mitigate DoS attacks against sshd. See the
`MaxStartups' option in the sshd manpage for details (Markus Friedl)
- `-u' option to sshd allow logging of hostnames (rather than IP
addresses) in wtmp when `UseLogin' is set to `yes'. (Markus Friedl)
- Escape character `~' support in SSH2 (Markus Friedl)
- Interop with SSH.COM ssh 2.3.0 (Markus Friedl)
- Fix problems when sshd is run from inetd
- Better SunOS 4.1.x support (Nate Itkin and Charles Levert)
- Solaris package support, see contrib/solaris (Rip Loomis)
- Work around connection freezes on HPUX and SunOS 4 (Lutz Jaenicke,
Tamito KAJIYAMA)
- Fix ^C ignored issue on Solaris. (Gert Doering, John Horne and
Garrick James)
- Further improved NeXT support. (Ben Lindstrom, Mark Miller)
- Lots of other minor fixes (see ChangeLog for details)
This release has been tested on HPUX (10.20, 11.00), Irix (5.3,
6.5), Linux (Debian, Redhat, Slackware, SuSE), NeXTstep 3 (HPPA,
i386, m68k), OpenStep (i386, m68k, Sparc), SCO Unixware 7.1.0, SCO
OpenServer 5.0.5, Solaris 2.7 (Sparc), Solaris 2.8 (i386, Sparc),
SNI/Reliant Unix, DEC OSF/Tru64 5.0.
Many thanks to those who contributed bug reports, fixes and testing
time.
Regards,
Damien Miller
I have just uploaded portable OpenSSH 2.1.1p4, it should be making
its way to the mirrors listed at http://www.openssh.com/portable.html
soon.
This release contains several bugfixes from the OpenBSD team,
primarily the config file parsing problem reported by Ralf
Engelschall rse@engelschall.com
Regards,
Damien Miller
--------------- Changelog:
20000716
20000715
- (djm) OpenBSD CVS updates
- Fixes for SunOS 4.1.4 from Gordon Atwood gordon@cs.ualberta.ca
- Include floatingpoint.h for entropy.c
- strerror replacement
The 2.1.1p3 release of portable OpenSSH has been uploaded to the
OpenBSD ftp master site. In a few hours it will be available from one
of the many mirrors listed at:
http://www.openssh.com/portable.html
This release fixes several bugs reported since the previous release
and extends portability to NeXT and Reliant Unix.
As usual, the OpenBSD team has been hard at work further polishing and
enhancing OpenSSH. This release brings a new configuration directive
"MaxStartups" which mitigates connection flooding attacks, further
details are in the sshd man-page.
Another noteworthy difference from previous releases is that
'FallBackToRsh' now defaults to 'no'. Users of this feature may need
to edit their /etc/ssh_config or ~/.ssh/config files to achieve the
same behavior.
Again, thanks to those who reported bugs, tested the snapshot and sent
fixes.
Regards,
Damien Miller
------------------ Changelog
20000712
- (djm) Remove -lresolve for Reliant Unix
- (djm) OpenBSD CVS Updates:
- (djm) Replace in_addr_t with u_int32_t in bsd-inet_aton.c. Report from
Ben Lindstrom mouring@pconline.com
- (djm) Make building of X11-Askpass and GNOME-Askpass optional in RPM
spec file.
- (djm) Released 2.1.1p3
20000711
- (djm) Fixup for AIX getuserattr() support from Tom Bertelson
tbert@abac.com
- (djm) ReliantUNIX support from Udo Schweigert ust@cert.siemens.de
- (djm) NeXT: dirent structures to get scp working from Ben Lindstrom
mouring@pconline.com
- (djm) Fix broken inet_ntoa check and ut_user/ut_name confusion, report
from Jim Watt jimw@peisj.pebio.com
- (djm) Replaced bsd-snprintf.c with one from Mutt source tree, it is known
to compile on more platforms (incl NeXT).
- (djm) Added bsd-inet_aton and configure support for NeXT
- (djm) Misc NeXT fixes from Ben Lindstrom mouring@pconline.com
- (djm) OpenBSD CVS updates:
- (djm) Fix problem with debug mode and MaxStartups
- (djm) Don't generate host keys when $(DESTDIR) is set (e.g. during RPM
builds)
- (djm) Add strsep function from OpenBSD libc for systems that lack it
20000709
- (djm) Only enable PAM_TTY kludge for Linux. Problem report from
Kevin Steves stevesk@sweden.hp.com
- (djm) Match prototype and function declaration for rresvport_af.
Problem report from Niklas Edmundsson nikke@ing.umu.se
- (djm) Missing $(DESTDIR) on host-key target causing problems with RPM
builds. Problem report from Gregory Leblanc GLeblanc@cu-portland.edu
- (djm) Replace ut_name with ut_user. Patch from Jim Watt
jimw@peisj.pebio.com
- (djm) Fix pam sprintf fix
- (djm) Cleanup entropy collection code a little more. Split initialisation
from seeding, perform initialisation immediately at start, be careful with
uids. Based on problem report from Jim Watt jimw@peisj.pebio.com
- (djm) More NeXT compatibility from Ben Lindstrom mouring@pconline.com
Including sigaction() et al. replacements
- (djm) AIX getuserattr() session initialisation from Tom Bertelson
tbert@abac.com
20000708
20000702
- (djm) Fix brace mismatch from Corinna Vinschen vinschen@cygnus.com
- (djm) Stop shadow expiry checking from preventing logins with NIS. Based
on fix from HARUYAMA Seigo haruyama@nt.phys.s.u-tokyo.ac.jp
- (djm) Use standard OpenSSL functions in auth-skey.c. Patch from
Chris, the Young One cky@pobox.com
- (djm) Fix scp progress meter on really wide terminals. Based on patch
from James H. Cloos Jr. cloos@jhcloos.com
Announcing the release of portable OpenSSH 2.1.1p2.
This release primarily contains fixes to the bugs that have been
reported over the last month, in particular:
Invalid time bring written to utmp/wtmp on systems using bash2
Several lastlog fixes
AIX, SCO, Irix portability fixes
Avoid failures on PAM systems when using PAM authentication modules
which require a tty.
Entropy collection fixes for Solaris.
EGD robustness improvements
Fixes and enhancements from the OpenBSD team:
- Fixed options processing in authorized_keys2 file
- Compatibility with commercial SSH 2.0.13 and 2.2.0
- Numerous minor fixes
There are also a couple of new features:
Shadow password expiry support (no password change support yet)
Irix 6.x array sessions, project IDs and system audit trail IDs
Beginnings of Tru64 / OSF SIA (Security Integration Architecture)
support
Beginnings of NeXT support
Version 2.1.1p2 will be available from the mirrors listed at
http://www.openssh.com/portable.html (as soon as they update).
Many thanks to all those who tested the snapshots and/or contributed
bug reports and patches
Regards,
Damien Miller
Announcing the availability of portable OpenSSH 2.1.1p1.
This release contains the fix for the "UseLogin yes" vulnerability
identified in Markus' release and several other enhancements and
bugfixes. Including:
Better login code. Andre Lucas has rewritten the login code to
be much more modular and extensible. In the process he has fixed
the problems with Solaris utmp[x].
Revised the entropy collection code to be faster and more reliable.
Fix for RSA host restrictions ("from=" in authorized_keys)
It is recommended that all users upgrade to this version.
Portable OpenSSH 2.1.1p1 is available from one of the many mirrors
listed at: http://www.openssh.com/portable.html
Regards,
Damien Miller
This is to announce the release of openssh-2.1.0, the first stable
release of portable OpenSSH to incorporate support for the SSH2
protocol.
The SSH2 protocol offers a number of advantages over the SSH1 protocol
including standards compliance (SSH2 is on the IETF standards
track[1]), improved security and operation without RSA (which is
patented in some countries).
The SSH2 support in OpenSSH has been developed by Markus Friedl, with
support from the OpenBSD team.
This is also the first version of the portable version of OpenSSH
to offer built-in entropy collection. This removes the requirement
for EGD on systems that lack a /dev/random driver. As a result,
OpenSSH-2.1.0 now requires a recent version of OpenSSL[2] to compile
(version 0.9.5 or later).
NB. The portable version of OpenSSH is currently in the
process of merging its webpages with the official OpenBSD
project. Please use http://www.openssh.com/ from now
on. Distribution files are also available from the mirrors listed at
http://violet.ibs.com.au/openssh/files/MIRRORS.html
Please read http://www.openssh.com/report.html before reporting bugs.
Patches, bug reports, developer and user queries are welcome on the
mailing list (http://www.openssh.com/list.html).
Regards,
Damien Miller
[1] http://www.ietf.org/html.charters/secsh-charter.html
[2] http://www.openssl.org/
The Unix/Linux port of OpenSSH 1.2.3 was released yesterday and should
be available from a mirror near you. A mirror list is available from:
http://violet.ibs.com.au/openssh/files/MIRRORS.html
This release fixes the bugs reported since 1.2.2p1 and contains many
cleanups from the OpenBSD tree.
In particular, the OpenSSL detection problems have been resolved.
The layout has changed a little bit. The packages/ subdirectory has
been replaced with a contrib/ subdirectory which contains platform
specific code and other patches. Submissions are welcome.
Enjoy,
Damien Miller
20000317
- Clarified --with-default-path option.
- Added -blibpath handling for AIX to work around stupid runtime linking.
Problem elucidated by gshapiro@SENDMAIL.ORG by way of Jim Knoble
jmknoble@pobox.com
- Checks for 64 bit int types. Problem report from Mats Fredholm
matsf@init.se
- OpenBSD CVS updates:
- [atomicio.c auth-krb4.c bufaux.c channels.c compress.c fingerprint.c]
[packet.h radix.c rsa.c scp.c ssh-agent.c ssh-keygen.c sshconnect.c]
[sshd.c]
pedantic: signed vs. unsigned, void*-arithm, etc
- [ssh.1 sshd.8]
Various cleanups and standardizations.
- Runtime error fix for HPUX from Otmar Stahl
O.Stahl@lsw.uni-heidelberg.de
20000316
- Fixed configure not passing LDFLAGS to Solaris. Report from David G.
Hesprich dghespri@sprintparanet.com
- Propagate LD through to Makefile
- Doc cleanups
- Added blurb about "scp: command not found" errors to UPGRADING
20000315
- Fix broken CFLAGS handling during search for OpenSSL. Fixes va_list
problems with gcc/Solaris.
- Don't free argument to putenv() after use (in setenv() replacement).
Report from Seigo Tanimura tanimura@r.dl.itc.u-tokyo.ac.jp
- Created contrib/ subdirectory. Included helpers from Phil Hands'
Debian package, README file and chroot patch from Ricardo Cerqueira
rmcc@clix.pt
- Moved gnome-ssh-askpass.c to contrib directory and removed config
option.
- Slight cleanup to doc files
- Configure fix from Bratislav ILICH bilic@zepter.ru
20000314
- Include macro for IN6_IS_ADDR_V4MAPPED. Report from
peter@frontierflying.com
- Include /usr/local/include and /usr/local/lib for systems that don't
do it themselves
- -R/usr/local/lib for Solaris
- Fix RSAref detection
- Fix IN6_IS_ADDR_V4MAPPED macro
20000311
- Detect RSAref
- OpenBSD CVS change
[sshd.c]
- disallow guessing of root password
- More configure fixes
- IPv6 workarounds from Hideaki YOSHIFUJI yoshfuji@ecei.tohoku.ac.jp
20000309
- OpenBSD CVS updates to v1.2.3
[ssh.h atomicio.c]
- int atomicio -> ssize_t (for alpha). ok deraadt@
[auth-rsa.c]
- delay MD5 computation until client sends response, free() early, cleanup.
[cipher.c]
- void* -> unsigned char*, ok niels@
[hostfile.c]
- remove unused variable 'len'. fix comments.
- remove unused variable
[log-client.c log-server.c]
- rename a cpp symbol, to avoid param.h collision
[packet.c]
- missing xfree()
- getsockname() requires initialized tolen; andy@guildsoftware.com
- use getpeername() in packet_connection_is_on_socket(), fixes sshd -i;
from Holger.Trapp@Informatik.TU-Chemnitz.DE
[pty.c pty.h]
- register cleanup for pty earlier. move code for pty-owner handling to
pty.c ok provos@, dugsong@
[readconf.c]
- turn off x11-fwd for the client, too.
[rsa.c]
- PKCS#1 padding
[scp.c]
- allow '.' in usernames; from jedgar@fxp.org
[servconf.c]
- typo: ignore_user_known_hosts int->flag; naddy@mips.rhein-neckar.de
- sync with sshd_config
[ssh-keygen.c]
- enable ssh-keygen -l -f ~/.ssh/known_hosts, ok deraadt@
[ssh.1]
- Change invalid 'CHAT' loglevel to 'VERBOSE'
[ssh.c]
- suppress AAAA query host when '-4' is used; from shin@nd.net.fujitsu.co.jp
- turn off x11-fwd for the client, too.
[sshconnect.c]
- missing xfree()
- retry rresvport_af(), too. from sumikawa@ebina.hitachi.co.jp.
- read error vs. "Connection closed by remote host"
[sshd.8]
- ie. -> i.e.,
- do not link to a commercial page..
- sync with sshd_config
[sshd.c]
- no need for poll.h; from bright@wintelcom.net
- log with level log() not fatal() if peer behaves badly.
- don't panic if client behaves strange. ok deraadt@
- make no-port-forwarding for RSA keys deny both -L and -R style fwding
- delay close() of pty until the pty has been chowned back to root
- oops, fix comment, too.
- missing xfree()
- move XAUTHORITY to subdir. ok dugsong@. fixes debian bug #57907, too.
(http://cgi.debian.org/cgi-bin/bugreport.cgi?archive=no&bug=57907) - register cleanup for pty earlier. move code for pty-owner handling to
pty.c ok provos@, dugsong@
- create x11 cookie file
- fix pr 1113, fclose() -> pclose(), todo: remote popen()
- version 1.2.3
- Cleaned up
- Removed warning workaround for Linux and devpts filesystems (no longer
required after OpenBSD updates)
20000308
It gives me no little pleasure to announce the first stable release
of the Unix port of OpenSSH.
It is available in tar.gz and RPM format from one of the mirrors
listed at:
http://violet.ibs.com.au/openssh/files/MIRRORS.html
This release fixes all known issues and is known to compile and
function on (at least) recent releases on Linux, Solaris, HPUX and SCO
Unixware.
Please review the ChangeLog[1] for details on what has changed since
the last release.
I am holding off on a wider announcement until the mirrors have
updated.
Thanks to everyone who assisted with testing, bug reports, success
stories and most of all, patches :) Special thanks to the OpenBSD
developers for giving us OpenSSH to begin with.
Regards,
Damien Miller
[1] http://violet.ibs.com.au/openssh/files/ChangeLog
$OpenBSD: releasenotes.html,v 1.94 2026/10/06 17:17:07 tj Exp $
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