===================================================================== CERT-Renater Note d'Information No. 2023/VULN048 _____________________________________________________________________ DATE : 03/02/2023 HARDWARE PLATFORM(S): / OPERATING SYSTEM(S): Systems running OpenSSH versions prior to 9.2. ===================================================================== https://lists.mindrot.org/pipermail/openssh-unix-announce/2023-February/000150.html _____________________________________________________________________ OpenSSH 9.2 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 9.1 ========================= This release fixes a number of security bugs. Security ======== This release contains fixes for two security problems and a memory safety problem. The memory safety problem is not believed to be exploitable, but we report most network-reachable memory faults as security bugs. * sshd(8): fix a pre-authentication double-free memory fault introduced in OpenSSH 9.1. This is not believed to be exploitable, and it occurs in the unprivileged pre-auth process that is subject to chroot(2) and is further sandboxed on most major platforms. * ssh(8): in OpenSSH releases after 8.7, the PermitRemoteOpen option would ignore its first argument unless it was one of the special keywords "any" or "none", causing the permission list to fail open if only one permission was specified. bz3515 * ssh(1): if the CanonicalizeHostname and CanonicalizePermittedCNAMEs options were enabled, and the system/libc resolver did not check that names in DNS responses were valid, then use of these options could allow an attacker with control of DNS to include invalid characters (possibly including wildcards) in names added to known_hosts files when they were updated. These names would still have to match the CanonicalizePermittedCNAMEs allow-list, so practical exploitation appears unlikely. Potentially-incompatible changes -------------------------------- * ssh(1): add a new EnableEscapeCommandline ssh_config(5) option that controls whether the client-side ~C escape sequence that provides a command-line is available. Among other things, the ~C command-line could be used to add additional port-forwards at runtime. This option defaults to "no", disabling the ~C command-line that was previously enabled by default. Turning off the command-line allows platforms that support sandboxing of the ssh(1) client (currently only OpenBSD) to use a stricter default sandbox policy. New features ------------ * sshd(8): add support for channel inactivity timeouts via a new sshd_config(5) ChannelTimeout directive. This allows channels that have not seen traffic in a configurable interval to be automatically closed. Different timeouts may be applied to session, X11, agent and TCP forwarding channels. * sshd(8): add a sshd_config UnusedConnectionTimeout option to terminate client connections that have no open channels for a length of time. This complements the ChannelTimeout option above. * sshd(8): add a -V (version) option to sshd like the ssh client has. * ssh(1): add a "Host" line to the output of ssh -G showing the original hostname argument. bz3343 * scp(1), sftp(1): add a -X option to both scp(1) and sftp(1) to allow control over some SFTP protocol parameters: the copy buffer length and the number of in-flight requests, both of which are used during upload/download. Previously these could be controlled in sftp(1) only. This makes them available in both SFTP protocol clients using the same option character sequence. * ssh-keyscan(1): allow scanning of complete CIDR address ranges, e.g. "ssh-keyscan 192.168.0.0/24". If a CIDR range is passed, then it will be expanded to all possible addresses in the range including the all-0s and all-1s addresses. bz#976 * ssh(1): support dynamic remote port forwarding in escape command-line's -R processing. bz#3499 Bugfixes -------- * ssh(1): when restoring non-blocking mode to stdio fds, restore exactly the flags that ssh started with and don't just clobber them with zero, as this could also remove the append flag from the set. bz3523 * ssh(1): avoid printf("%s", NULL) if using UserKnownHostsFile=none and a hostkey in one of the system known hosts file changes. * scp(1): switch scp from using pipes to a socket-pair for communication with its ssh sub-processes, matching how sftp(1) operates. * sshd(8): clear signal mask early in main(); sshd may have been started with one or more signals masked (sigprocmask(2) is not cleared on fork/exec) and this could interfere with various things, e.g. the login grace timer. Execution environments that fail to clear the signal mask before running sshd are clearly broken, but apparently they do exist. * ssh(1): warn if no host keys for hostbased auth can be loaded. * sshd(8): Add server debugging for hostbased auth that is queued and sent to the client after successful authentication, but also logged to assist in diagnosis of HostbasedAuthentication problems. bz3507 * ssh(1): document use of the IdentityFile option as being usable to list public keys as well as private keys. GHPR352 * sshd(8): check for and disallow MaxStartups values less than or equal to zero during config parsing, rather than failing later at runtime. bz3489 * ssh-keygen(1): fix parsing of hex cert expiry times specified on the command-line when acting as a CA. * scp(1): when scp(1) is using the SFTP protocol for transport (the default), better match scp/rcp's handling of globs that don't match the globbed characters but do match literally (e.g. trying to transfer a file named "foo.[1]"). Previously scp(1) in SFTP mode would not match these pathnames but legacy scp/rcp mode would. bz3488 * ssh-agent(1): document the "-O no-restrict-websafe" command-line option. * ssh(1): honour user's umask(2) if it is more restrictive then the ssh default (022). Portability ----------- * sshd(8): allow writev(2) in the Linux seccomp sandbox. This seems to be used by recent glibcs at least in some configurations during error conditions. bz3512. * sshd(8): simply handling of SSH_CONNECTION PAM env var, removing global variable and checking the return value from pam_putenv. bz3508 * sshd(8): disable SANDBOX_SECCOMP_FILTER_DEBUG that was mistakenly enabled during the OpenSSH 9.1 release cycle. * misc: update autotools and regenerate the config files using the latest autotools * all: use -fzero-call-used-regs=used on clang 15 instead of -fzero-call-used-reg=all, as some versions of clang 15 have miscompile code when it was enabled. bz3475 * sshd(8): defer PRNG seeding until after the initial closefrom(2) call. PRNG seeding will initialize OpenSSL, and some engine providers (e.g. Intel's QAT) will open descriptors for their own use that closefrom(2) could clobber. bz3483 * misc: in the poll(2)/ppoll(2) compatibility code, avoid assuming the layout of fd_set. * sftp-server(8), ssh-agent(1): fix ptrace(2) disabling on older FreeBSD kernels. Some versions do not support using id 0 to refer to the current PID for procctl, so try again with getpid() explicitly before failing. * configure.ac: fix -Wstrict-prototypes in configure test code. Clang 16 now warns on this and legacy prototypes will be removed in C23. GHPR355 * configure.ac: fix setres*id checks to work with clang-16. glibc has the prototypes for setresuid behind _GNU_SOURCE, and clang 16 will error out on implicit function definitions. bz3497 Checksums: ========== - SHA1 (openssh-9.2.tar.gz) = e4b806b7c81b87d6c90afe97b3d016ba6cf3ba1c - SHA256 (openssh-9.2.tar.gz) = yYe9uaaWSeetXGXOxuaaEiIsLnvITmGW+l5dgMZb9QU= - SHA1 (openssh-9.2p1.tar.gz) = 3b172b8e971773a7018bbf3231f6589ae539ca4b - SHA256 (openssh-9.2p1.tar.gz) = P2bb8WVftF9Q4cVtpiqwEhjCKIB7ITONY068351xz0Y= 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 ========================================================= + CERT-RENATER | tel : 01-53-94-20-44 + + 23/25 Rue Daviel | fax : 01-53-94-20-41 + + 75013 Paris | email:cert@support.renater.fr + =========================================================