Changelog
openssh (1:6.9p1-1) unstable; urgency=medium
* New upstream release (http://www.openssh.com/txt/release-6.8):
- 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.
- 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 avoids needless DNS lookups in some cases.
- 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 (closes: #481133). 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".
- ssh-keyscan(1): ssh-keyscan has been made much more robust against
servers that hang or violate the SSH protocol (closes: #241119).
- ssh(1), ssh-keygen(1): Fix regression bz#2306: Key path names were
being lost as comment fields (closes: #787776).
- ssh(1): Allow ssh_config Port options set in the second config parse
phase to be applied (they were being ignored; closes: #774369).
- 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)
- ssh(1): Fix passing of wildcard forward bind addresses when connection
multiplexing is in use.
- ssh-keygen(1): Fix broken private key conversion from non-OpenSSH
formats.
- ssh-keygen(1): Fix KRL generation bug when multiple CAs are in use.
* New upstream release (http://www.openssh.com/txt/release-6.9):
- CVE-2015-5352: 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 (closes: #790798). This problem was reported
by Jann Horn.
- SECURITY: 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.
- sshd(8): Support admin-specified arguments to AuthorizedKeysCommand
(closes: #740494).
- 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.
- 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.
- 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).
- 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 (closes: #740307, LP: #1287222).
- ssh(1): Fix out-of-bound read in EscapeChar configuration option
parsing.
- sshd(8): Fix application of PermitTunnel, LoginGraceTime,
AuthenticationMethods and StreamLocalBindMask options in Match blocks.
- ssh(1), sshd(8): Improve disconnection message on TCP reset.
- ssh(1): Remove failed remote forwards established by multiplexing from
the list of active forwards.
- sshd(8): Make parsing of authorized_keys "environment=" options
independent of PermitUserEnv being enabled.
- sshd(8): Fix post-auth crash with permitopen=none (closes: #778807).
- ssh(1), ssh-add(1), ssh-keygen(1): Allow new-format private keys to be
encrypted with AEAD ciphers.
- ssh(1): Allow ListenAddress, Port and AddressFamily configuration
options to appear in any order.
- sshd(8): Check for and reject missing arguments for VersionAddendum
and ForceCommand.
- ssh(1), sshd(8): Don't treat unknown certificate extensions as fatal.
- ssh-keygen(1): Make stdout and stderr output consistent.
- ssh(1): Mention missing DISPLAY environment in debug log when X11
forwarding requested.
- sshd(8): Correctly record login when UseLogin is set.
- sshd(8): Add some missing options to sshd -T output and fix output of
VersionAddendum and HostCertificate.
- Document and improve consistency of options that accept a "none"
argument: TrustedUserCAKeys, RevokedKeys, AuthorizedPrincipalsFile.
- ssh(1): Include remote username in debug output.
- sshd(8): Avoid compatibility problem with some versions of Tera Term,
which would crash when they received the hostkeys notification message
(<email address hidden>).
- sshd(8): Mention ssh-keygen -E as useful when comparing legacy MD5
host key fingerprints.
- ssh(1): Clarify pseudo-terminal request behaviour and make manual
language consistent.
- ssh(1): Document that the TERM environment variable is not subject to
SendEnv and AcceptEnv; bz#2386
- sshd(8): Format UsePAM setting when using sshd -T (closes: #767648).
- moduli(5): Update DH-GEX moduli (closes: #787037).
* There are some things I want to fix before upgrading to 7.0p1, though I
intend to do that soon. In the meantime, backport some patches, mainly
to fix security issues:
- 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.
- SECURITY: sshd(8): 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.
- SECURITY: sshd(8): 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 (closes:
#795711). Also reported by Moritz Jodeit.
- CVE-2015-5600: sshd(8): Fix circumvention of MaxAuthTries using
keyboard-interactive authentication (closes: #793616). 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.
- Let principals-command.sh work for noexec /var/run.
* Thanks to Jakub Jelen of Red Hat for Fedora's rebased version of the
GSSAPI key exchange patch.
* Document the Debian-specific change to the default value of
ForwardX11Trusted in ssh(1) (closes: #781469).
-- Colin Watson <email address hidden> Thu, 20 Aug 2015 10:38:58 +0100
