Mailing List Archive

Announce: OpenSSH 8.0 released
OpenSSH 8.0 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.

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The scp protocol is outdated, inflexible and not readily fixed.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 establised 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 requring 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 siganture 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:
==========

- SHA1 (openssh-8.0.tar.gz) = 8aaa99091fc7e5a92a4a320e1e5521046b3f95f0
- SHA256 (openssh-8.0.tar.gz) = 1xvSJk1KYSnOLPYEUzyCVwTEQ7MHOaCO65DzeNuuLdo=

- SHA1 (openssh-8.0p1.tar.gz) = 756dbb99193f9541c9206a667eaa27b0fa184a4f
- SHA256 (openssh-8.0p1.tar.gz) = vZQ4eeaUmOgDHra39E0IzcN9WaeraJqgtDcyDDSB/Wg=

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
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