Damien Miller
2024-Sep-20 00:10 UTC
[openssh-unix-announce] Announce: OpenSSH 9.9 released
OpenSSH 9.9 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 Future deprecation notice ======================== OpenSSH plans to remove support for the DSA signature algorithm in early 2025. This release disables DSA by default at compile time. DSA, as specified in the SSHv2 protocol, is inherently weak - being limited to a 160 bit private key and use of the SHA1 digest. Its estimated security level is only 80 bits symmetric equivalent. OpenSSH has disabled DSA keys by default since 2015 but has retained run-time optional support for them. DSA was the only mandatory-to- implement algorithm in the SSHv2 RFCs, mostly because alternative algorithms were encumbered by patents when the SSHv2 protocol was specified. This has not been the case for decades at this point and better algorithms are well supported by all actively-maintained SSH implementations. We do not consider the costs of maintaining DSA in OpenSSH to be justified and hope that removing it from OpenSSH can accelerate its wider deprecation in supporting cryptography libraries. Currently DSA is disabled at compile time. The final step of removing DSA support entirely is planned for the first OpenSSH release of 2025. DSA support may be re-enabled on OpenBSD by setting "DSAKEY=yes" in Makefile.inc. To enable DSA support in portable OpenSSH, pass the "--enable-dsa-keys" option to configure. Potentially-incompatible changes -------------------------------- * ssh(1): remove support for pre-authentication compression. OpenSSH has only supported post-authentication compression in the server for some years. Compression before authentication significantly increases the attack surface of SSH servers and risks creating oracles that reveal information about information sent during authentication. * ssh(1), sshd(8): processing of the arguments to the "Match" configuration directive now follows more shell-like rules for quoted strings, including allowing nested quotes and \-escaped characters. If configurations contained workarounds for the previous simplistic quote handling then they may need to be adjusted. If this is the case, it's most likely to be in the arguments to a "Match exec" confition. In this case, moving the command to be evaluated from the Match line to an external shell script is easiest way to preserve compatibility with both the old and new versions. Changes since OpenSSH 9.8 ======================== This release contains a number of new features and bugfixes. New features ------------ * ssh(1), sshd(8): add support for a new hybrid post-quantum key exchange based on the FIPS 203 Module-Lattice Key Enapsulation mechanism (ML-KEM) combined with X25519 ECDH as described by https://datatracker.ietf.org/doc/html/draft-kampanakis-curdle-ssh-pq-ke-03 This algorithm "mlkem768x25519-sha256" is available by default. * ssh(1): the ssh_config "Include" directive can now expand environment as well as the same set of %-tokens "Match Exec" supports. * sshd(8): add a sshd_config "RefuseConnection" option that, if set will terminate the connection at the first authentication request. * sshd(8): add a "refuseconnection" penalty class to sshd_config PerSourcePenalties that is applied when a connection is dropped by the new RefuseConnection keyword. * sshd(8): add a "Match invalid-user" predicate to sshd_config Match options that matches when the target username is not valid on the server. * ssh(1), sshd(8): update the Streamlined NTRUPrime code to a substantially faster implementation. * ssh(1), sshd(8): the hybrid Streamlined NTRUPrime/X25519 key exchange algorithm now has an IANA-assigned name in addition to the "@openssh.com" vendor extension name. This algorithm is now also available under this name "sntrup761x25519-sha512" * ssh(1), sshd(8), ssh-agent(1): prevent private keys from being included in core dump files for most of their lifespans. This is in addition to pre-existing controls in ssh-agent(1) and sshd(8) that prevented coredumps. This feature is supported on OpenBSD, Linux and FreeBSD. * All: convert key handling to use the libcrypto EVP_PKEY API, with the exception of DSA. * sshd(8): add a random amount of jitter (up to 4 seconds) to the grace login time to make its expiry unpredictable. Bugfixes -------- * sshd(8): relax absolute path requirement back to what it was prior to OpenSSH 9.8, which incorrectly required that sshd was started with an absolute path in inetd mode. bz3717 * sshd(8): fix regression introduced in openssh-9.8 that swapped the order of source and destination addresses in some sshd log messages. * sshd(8): do not apply authorized_keys options when signature verification fails. Prevents more restrictive key options being incorrectly applied to subsequent keys in authorized_keys. bz3733 * ssh-keygen(1): include pathname in some of ssh-keygen's passphrase prompts. Helps the user know what's going on when ssh-keygen is invoked via other tools. Requested in GHPR503 * ssh(1), ssh-add(1): make parsing user at host consistently look for the last '@' in the string rather than the first. This makes it possible to more consistently use usernames that contain '@' characters. * ssh(1), sshd(8): be more strict in parsing key type names. Only allow short names (e.g "rsa") in user-interface code and require full SSH protocol names (e.g. "ssh-rsa") everywhere else. bz3725 * regress: many performance and correctness improvements to the re-keying regression test. * ssh-keygen(1): clarify that ed25519 is the default key type generated and clarify that rsa-sha2-512 is the default signature scheme when RSA is in use. GHPR505 * sshd(8): fix minor memory leak in Subsystem option parsing; GHPR515 * All: additional hardening and consistency checks for the sshbuf code. * sshd(8): reduce default logingrace penalty to ensure that a single forgotton login that times out will be below the penalty threshold. * ssh(1): fix proxy multiplexing (-O proxy) bug. If a mux started with ControlPersist then later has a forwarding added using mux proxy connection and the forwarding was used, then when the mux proxy session terminated, the mux master process would issue a bad message that terminated the connection. Portability ----------- * sync contrib/ssh-copy-id to the latest upstream version. * regress: improve portablility for some awk(1) usage (e.g. Solaris) * In the contrib/redhat RPM spec file, without_openssl was previously incorrectly enabled unconditionally. * sshd(8) restore audit call before exit that regressed in openssh-9.8 Fixes an issue where the SSH_CONNECTION_ABANDON event was not recorded. * sshd(8): add support for class-imposed loging restrictions on FreeBSD. Allowing auth_hostok(3) and auth_timeok(3) to control logins. * Build fixes for Musl libc. * Fix detection of setres*id on GNU/Hurd Checksums: ========= - SHA1 (openssh-9.9.tar.gz) = 080acf6ff0b862e8faa3baa3920a079536d28e85 - SHA256 (openssh-9.9.tar.gz) = h1xwa7CVcJfN7I9MgxxPBpUELzo+tnmLy+6slYHTUtw - SHA1 (openssh-9.9p1.tar.gz) = 5ded7eb0add0b02b5d1a1c4bf5cb2c89d2117b53 - SHA256 (openssh-9.9p1.tar.gz) = s0P7zb/4fxWxmG5uFdbU/Jp9NgZr5rf7UHCHuo+WbAI 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