mirrors listed at http://www.openssh.com/ shortly.
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:
==========
- SHA1 (openssh-7.7.tar.gz) = 24812e05fa233014c847c7775748316e7f8a836c
- SHA256 (openssh-7.7.tar.gz) = T4ua1L/vgAYqwB0muRahvnm5ZUr3PLY9nPljaG8egvo=
- SHA1 (openssh-7.7p1.tar.gz) = 446fe9ed171f289f0d62197dffdbfdaaf21c49f2
- SHA256 (openssh-7.7p1.tar.gz) = 1zvn5oTpnvzQJL4Vowv/y+QbASsvezyQhK7WIXdea48=
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:
===============
- Please read http://www.openssh.com/report.html
Security bugs should be reported directly to openssh@openssh.com
================================
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.
mirrors listed at http://www.openssh.com/ shortly.
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).
OpenSSH 7.4 has just been released. It will be available from the
mirrors listed at http://www.openssh.com/ shortly.
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.
mirrors listed at http://www.openssh.com/ shortly.
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:
==========
- SHA1 (openssh-7.3.tar.gz) = b1641e5265d9ec68a9a19decc3a7edd1203cbd33
- SHA256 (openssh-7.3.tar.gz) = vS0X35qrX9OOPBkyDMYhOje/DBwHBVEV7nv5rkzw4vM=
- SHA1 (openssh-7.3p1.tar.gz) = bfade84283fcba885e2084343ab19a08c7d123a5
- SHA256 (openssh-7.3p1.tar.gz) = P/uYmm3KppWUw7VQ1IVaWi4XGMzd5/XjY4e0JCIPvsw=
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:
===============
- Please read http://www.openssh.com/report.html
Security bugs should be reported directly to openssh@openssh.com
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.
=========================
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
=========================
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 compatability workarounds for FuTTY
* ssh(1), sshd(8): refine compatability 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.
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 compatability 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 wth
empty CKA_ID; bz#2429
* sshd(8): clarify documentation for UseDNS option; bz#2045
=========================
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
=========================
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:
==========
- SHA1 (openssh-6.8.tar.gz) = 99903c6ca76e0a2c044711017f81127e12459d37
- SHA256 (openssh-6.8.tar.gz) = N1uzVarFbrm2CzAwuDu3sRoszmqpK+5phAChP/QNyuw=
- SHA1 (openssh-6.8p1.tar.gz) = cdbc51e46a902b30d263b05fdc71340920e91c92
- SHA256 (openssh-6.8p1.tar.gz) = P/ZM5z7hJEgLW/dnuYMNfTwDu8tqvnFrePAZLDfOFg4=
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:
===============
- Please read http://www.openssh.com/report.html
Security bugs should be reported directly to openssh@openssh.com
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.
=========================
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 identifer 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}
Changes since OpenSSH 6.5
=========================
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 enviornment 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.
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 retart.
* 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.
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:
==========
- SHA1 (openssh-6.4.tar.gz) = 4caf1a50eb3a3da821c16298c4aaa576fe24210c
- SHA1 (openssh-6.4p1.tar.gz) = cf5fe0eb118d7e4f9296fbc5d6884965885fc55d
Reporting Bugs:
===============
- Please read http://www.openssh.com/report.html
Security bugs should be reported directly to openssh@openssh.com
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.
christos