OpenSSH 8.9 was released on 2022-02-23. It is available from the mirrors listed at https://www.openssh.com/. 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 ========================= A near-future release of OpenSSH will switch scp(1) from using the legacy scp/rcp protocol to using SFTP by default. Legacy scp/rcp performs wildcard expansion of remote filenames (e.g. "scp host:* .") through the remote shell. This has the side effect of requiring double quoting of shell meta-characters in file names included on scp(1) command-lines, otherwise they could be interpreted as shell commands on the remote side. This creates one area of potential incompatibility: scp(1) when using the SFTP protocol no longer requires this finicky and brittle quoting, and attempts to use it may cause transfers to fail. We consider the removal of the need for double-quoting shell characters in file names to be a benefit and do not intend to introduce bug-compatibility for legacy scp/rcp in scp(1) when using the SFTP protocol. Another area of potential incompatibility relates to the use of remote paths relative to other user's home directories, for example - "scp host:~user/file /tmp". The SFTP protocol has no native way to expand a ~user path. However, sftp-server(8) in OpenSSH 8.7 and later support a protocol extension "expand-path@openssh.com" to support this. Security Near Miss ================== * sshd(8): fix an integer overflow in the user authentication path that, in conjunction with other logic errors, could have yielded unauthenticated access under difficult to exploit conditions. This situation is not exploitable because of independent checks in the privilege separation monitor. Privilege separation has been enabled by default in since openssh-3.2.2 (released in 2002) and has been mandatory since openssh-7.5 (released in 2017). Moreover, portable OpenSSH has used toolchain features available in most modern compilers to abort on signed integer overflow since openssh-6.5 (released in 2014). Thanks to Malcolm Stagg for finding and reporting this bug. Potentially-incompatible changes ================================ * sshd(8), portable OpenSSH only: this release removes in-built support for MD5-hashed passwords. If you require these on your system then we recommend linking against libxcrypt or similar. * This release modifies the FIDO security key middleware interface and increments SSH_SK_VERSION_MAJOR. Changes since OpenSSH 8.8 ========================= This release includes a number of new features. New features ------------ * ssh(1), sshd(8), ssh-add(1), ssh-agent(1): add a system for restricting forwarding and use of keys added to ssh-agent(1) A detailed description of the feature is available at https://www.openssh.com/agent-restrict.html and the protocol extensions are documented in the PROTOCOL and PROTOCOL.agent files in the source release. * ssh(1), sshd(8): add the sntrup761x25519-sha512@openssh.com hybrid ECDH/x25519 + Streamlined NTRU Prime post-quantum KEX to the default KEXAlgorithms list (after the ECDH methods but before the prime-group DH ones). The next release of OpenSSH is likely to make this key exchange the default method. * ssh-keygen(1): when downloading resident keys from a FIDO token, pass back the user ID that was used when the key was created and append it to the filename the key is written to (if it is not the default). Avoids keys being clobbered if the user created multiple resident keys with the same application string but different user IDs. * ssh-keygen(1), ssh(1), ssh-agent(1): better handling for FIDO keys on tokens that provide user verification (UV) on the device itself, including biometric keys, avoiding unnecessary PIN prompts. * ssh-keygen(1): add "ssh-keygen -Y match-principals" operation to perform matching of principals names against an allowed signers file. To be used towards a TOFU model for SSH signatures in git. * ssh-add(1), ssh-agent(1): allow pin-required FIDO keys to be added to ssh-agent(1). $SSH_ASKPASS will be used to request the PIN at authentication time. * ssh-keygen(1): allow selection of hash at sshsig signing time (either sha512 (default) or sha256). * ssh(1), sshd(8): read network data directly to the packet input buffer instead of indirectly via a small stack buffer. Provides a modest performance improvement. * ssh(1), sshd(8): read data directly to the channel input buffer, providing a similar modest performance improvement. * ssh(1): extend the PubkeyAuthentication configuration directive to accept yes|no|unbound|host-bound to allow control over one of the protocol extensions used to implement agent-restricted keys. Bugfixes -------- * sshd(8): document that CASignatureAlgorithms, ExposeAuthInfo and PubkeyAuthOptions can be used in a Match block. PR#277. * sshd(8): fix possible string truncation when constructing paths to .rhosts/.shosts files with very long user home directory names. * ssh-keysign(1): unbreak for KEX algorithms that use SHA384/512 exchange hashes * ssh(1): don't put the TTY into raw mode when SessionType=none, avoids ^C being unable to kill such a session. bz3360 * scp(1): fix some corner-case bugs in SFTP-mode handling of ~-prefixed paths. * ssh(1): unbreak hostbased auth using RSA keys. Allow ssh(1) to select RSA keys when only RSA/SHA2 signature algorithms are configured (this is the default case). Previously RSA keys were not being considered in the default case. * ssh-keysign(1): make ssh-keysign use the requested signature algorithm and not the default for the key type. Part of unbreaking hostbased auth for RSA/SHA2 keys. * ssh(1): stricter UpdateHostkey signature verification logic on the client- side. Require RSA/SHA2 signatures for RSA hostkeys except when RSA/SHA1 was explicitly negotiated during initial KEX; bz3375 * ssh(1), sshd(8): fix signature algorithm selection logic for UpdateHostkeys on the server side. The previous code tried to prefer RSA/SHA2 for hostkey proofs of RSA keys, but missed some cases. This will use RSA/SHA2 signatures for RSA keys if the client proposed these algorithms in initial KEX. bz3375 * All: convert all uses of select(2)/pselect(2) to poll(2)/ppoll(2). This includes the mainloops in ssh(1), ssh-agent(1), ssh-agent(1) and sftp-server(8), as well as the sshd(8) listen loop and all other FD read/writability checks. On platforms with missing or broken poll(2)/ppoll(2) syscalls a select(2)-based compat shim is available. * ssh-keygen(1): the "-Y find-principals" command was verifying key validity when using ca certs but not with simple key lifetimes within the allowed signers file. * ssh-keygen(1): make sshsig verify-time argument parsing optional * sshd(8): fix truncation in rhosts/shosts path construction. * ssh(1), ssh-agent(1): avoid xmalloc(0) for PKCS#11 keyid for ECDSA keys (we already did this for RSA keys). Avoids fatal errors for PKCS#11 libraries that return empty keyid, e.g. Microchip ATECC608B "cryptoauthlib"; bz#3364 * ssh(1), ssh-agent(1): improve the testing of credentials against inserted FIDO: ask the token whether a particular key belongs to it in cases where the token supports on-token user-verification (e.g. biometrics) rather than just assuming that it will accept it. Will reduce spurious "Confirm user presence" notifications for key handles that relate to FIDO keys that are not currently inserted in at least some cases. bz3366 * ssh(1), sshd(8): correct value for IPTOS_DSCP_LE. It needs to allow for the preceding two ECN bits. bz#3373 * ssh-keygen(1): add missing -O option to usage() for the "-Y sign" option. * ssh-keygen(1): fix a NULL deref when using the find-principals function, when matching an allowed_signers line that contains a namespace restriction, but no restriction specified on the command-line * ssh-agent(1): fix memleak in process_extension(); oss-fuzz issue #42719 * ssh(1): suppress "Connection to xxx closed" messages when LogLevel is set to "error" or above. bz3378 * ssh(1), sshd(8): use correct zlib flags when inflate(3)-ing compressed packet data. bz3372 * scp(1): when recursively transferring files in SFTP mode, create the destination directory if it doesn't already exist to match scp(1) in legacy RCP mode behaviour. * scp(1): many improvements in error message consistency between scp(1) in SFTP mode vs legacy RCP mode. * sshd(8): fix potential race in SIGTERM handling PR#289 * ssh(1), ssh(8): since DSA keys are deprecated, move them to the end of the default list of public keys so that they will be tried last. PR#295 * ssh-keygen(1): allow 'ssh-keygen -Y find-principals' to match wildcard principals in allowed_signers files Portability ----------- * ssh(1), sshd(8): don't trust closefrom(2) on Linux. glibc's implementation does not work in a chroot when the kernel does not have close_range(2). It tries to read from /proc/self/fd and when that fails dies with an assertion of sorts. Instead, call close_range(2) directly from our compat code and fall back if that fails. bz#3349, * OS X poll(2) is broken; use compat replacement. For character- special devices like /dev/null, Darwin's poll(2) returns POLLNVAL when polled with POLLIN. Apparently this is Apple bug 3710161 - not public but a websearch will find other OSS projects rediscovering it periodically since it was first identified in 2005. * Correct handling of exceptfds/POLLPRI in our select(2)-based poll(2)/ppoll(2) compat implementation. * Cygwin: correct checking of mbstowcs() return value. * Add a basic SECURITY.md that refers people to the openssh.com website. * Enable additional compiler warnings and toolchain hardening flags, including -Wbitwise-instead-of-logical, -Wmisleading-indentation, -fzero-call-used-regs and -ftrivial-auto-var-init. * HP/UX. Use compat getline(3) on HP-UX 10.x, where the libc version is not reliable. Checksums: ========== - SHA1 (openssh-8.9.tar.gz) = 653310ba1a63959fe2df503fe7ad556445180127 - SHA256 (openssh-8.9.tar.gz) = mJigktP+Bk0sB7uRPuWgjcCOYZ+mIMdvRlZe66irtQA= - SHA1 (openssh-8.9p1.tar.gz) = 205cdf0040a238047e2c49f43460e03d76e5d650 - SHA256 (openssh-8.9p1.tar.gz) = /Ul2VLerFobaxnL7g9+0ukCW6LX/zazNJiOArli+xec= 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 Please note that the OpenPGP key used to sign releases has been rotated for this release. The new key has been signed by the previous key to provide continuity. Reporting Bugs: =============== - Please read https://www.openssh.com/report.html Security bugs should be reported directly to openssh@openssh.com