Log Message:
Update openssh to 7.3.1 (OpenSSH 7.3p1).

OpenSSH 7.3p1 is primarily a bugfix release and here is summary.

Changes since OpenSSH 7.2
=========================

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