Announce: OpenSSH 9.4 released

[Damien Miller]

OpenSSH 9.4 has just been released. It will be available from the
mirrors listed at https://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:
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 signatues 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 expicitly 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:
==========

 - SHA1 (openssh-9.4.tar.gz) = d88126d8d7b8e5bf4656587ac4a16055560641cc
 - SHA256 (openssh-9.4.tar.gz) = 7eqFjx2hAunw+1Jy7f1JQXq//3AMr9B3dKtASDtq8go=

 - SHA1 (openssh-9.4p1.tar.gz) = 5dea1f3c88f9cfe53a711a3c893ee8b7d3ffecff
 - SHA256 (openssh-9.4p1.tar.gz) = Ngj9kIjbIWPOs+YAyFq3nQ3j0iHlkZLqGSPiMmOGaoU=

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:
===============

- Please read https://www.openssh.com/report.html
  Security bugs should be reported directly to openssh at openssh.com