Highlights from the release notes are reproduced below. Some security
and bug fixes were previously merged into FreeBSD and have been elided.
See the upstream release notes for full details
(https://www.openssh.com/releasenotes.html).
---
Future deprecation notice
=========================
OpenSSH plans to remove support for the DSA signature algorithm in
early 2025.
Potentially-incompatible changes
--------------------------------
* sshd(8): the server will now block client addresses that
repeatedly fail authentication, repeatedly connect without ever
completing authentication or that crash the server. See the
discussion of PerSourcePenalties below for more information.
Operators of servers that accept connections from many users, or
servers that accept connections from addresses behind NAT or
proxies may need to consider these settings.
* sshd(8): the server has been split into a listener binary, sshd(8),
and a per-session binary "sshd-session". This allows for a much
smaller listener binary, as it no longer needs to support the SSH
protocol. As part of this work, support for disabling privilege
separation (which previously required code changes to disable) and
disabling re-execution of sshd(8) has been removed. Further
separation of sshd-session into additional, minimal binaries is
planned for the future.
* sshd(8): several log messages have changed. In particular, some
log messages will be tagged with as originating from a process
named "sshd-session" rather than "sshd".
* ssh-keyscan(1): this tool previously emitted comment lines
containing the hostname and SSH protocol banner to standard error.
This release now emits them to standard output, but adds a new
"-q" flag to silence them altogether.
* sshd(8): (portable OpenSSH only) sshd will no longer use argv[0]
as the PAM service name. A new "PAMServiceName" sshd_config(5)
directive allows selecting the service name at runtime. This
defaults to "sshd". bz2101
New features
------------
* sshd(8): sshd(8) will now penalise client addresses that, for various
reasons, do not successfully complete authentication. This feature is
controlled by a new sshd_config(5) PerSourcePenalties option and is
on by default.
* ssh(8): allow the HostkeyAlgorithms directive to disable the
implicit fallback from certificate host key to plain host keys.
Portability
-----------
* sshd(8): expose SSH_AUTH_INFO_0 always to PAM auth modules
unconditionally. The previous behaviour was to expose it only when
particular authentication methods were in use.
* ssh(1), ssh-agent(8): allow the presence of the WAYLAND_DISPLAY
environment variable to enable SSH_ASKPASS, similarly to the X11
DISPLAY environment variable. GHPR479
---
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D48914
(cherry picked from commit 0fdf8fae8b)
(cherry picked from commit b4bb480ae9)
(cherry picked from commit e95979047a)
(cherry picked from commit dcb4ae528d)
Approved by: re (accelerated MFC)
This release fixes a number of security bugs and has minor new
features and bug fixes. Security fixes, from the release notes
(https://www.openssh.com/txt/release-9.3):
This release contains fixes for a security problem 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.
* ssh-add(1): when adding smartcard keys to ssh-agent(1) with the
per-hop destination constraints (ssh-add -h ...) added in OpenSSH
8.9, a logic error prevented the constraints from being
communicated to the agent. This resulted in the keys being added
without constraints. The common cases of non-smartcard keys and
keys without destination constraints are unaffected. This problem
was reported by Luci Stanescu.
* ssh(1): Portable OpenSSH provides an implementation of the
getrrsetbyname(3) function if the standard library does not
provide it, for use by the VerifyHostKeyDNS feature. A
specifically crafted DNS response could cause this function to
perform an out-of-bounds read of adjacent stack data, but this
condition does not appear to be exploitable beyond denial-of-
service to the ssh(1) client.
The getrrsetbyname(3) replacement is only included if the system's
standard library lacks this function and portable OpenSSH was not
compiled with the ldns library (--with-ldns). getrrsetbyname(3) is
only invoked if using VerifyHostKeyDNS to fetch SSHFP records. This
problem was found by the Coverity static analyzer.
Sponsored by: The FreeBSD Foundation
Release notes are available at https://www.openssh.com/txt/release-9.1
9.1 contains fixes for three minor memory safety problems; these have
lready been merged to the copy of OpenSSH 9.0 that is in the FreeBSD base
system.
Some highlights copied from the release notes:
Potentially-incompatible changes
--------------------------------
* ssh(1), sshd(8): SetEnv directives in ssh_config and sshd_config
are now first-match-wins to match other directives. Previously
if an environment variable was multiply specified the last set
value would have been used. bz3438
* ssh-keygen(8): ssh-keygen -A (generate all default host key types)
will no longer generate DSA keys, as these are insecure and have
not been used by default for some years.
New features
------------
* ssh(1), sshd(8): add a RequiredRSASize directive to set a minimum
RSA key length. Keys below this length will be ignored for user
authentication and for host authentication in sshd(8).
* sftp-server(8): add a "users-groups-by-id@openssh.com" extension
request that allows the client to obtain user/group names that
correspond to a set of uids/gids.
* sftp(1): use "users-groups-by-id@openssh.com" sftp-server
extension (when available) to fill in user/group names for
directory listings.
* sftp-server(8): support the "home-directory" extension request
defined in draft-ietf-secsh-filexfer-extensions-00. This overlaps
a bit with the existing "expand-path@openssh.com", but some other
clients support it.
* ssh-keygen(1), sshd(8): allow certificate validity intervals,
sshsig verification times and authorized_keys expiry-time options
to accept dates in the UTC time zone in addition to the default
of interpreting them in the system time zone. YYYYMMDD and
YYMMDDHHMM[SS] dates/times will be interpreted as UTC if suffixed
with a 'Z' character.
Also allow certificate validity intervals to be specified in raw
seconds-since-epoch as hex value, e.g. -V 0x1234:0x4567890. This
is intended for use by regress tests and other tools that call
ssh-keygen as part of a CA workflow. bz3468
* sftp(1): allow arguments to the sftp -D option, e.g. sftp -D
"/usr/libexec/sftp-server -el debug3"
* ssh-keygen(1): allow the existing -U (use agent) flag to work
with "-Y sign" operations, where it will be interpreted to require
that the private keys is hosted in an agent; bz3429
MFC after: 2 weeks
Relnotes: Yes
Sponsored by: The FreeBSD Foundation
Release notes are available at https://www.openssh.com/txt/release-8.9
Some highlights:
* 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)
* 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.
* 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.
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.
MFC after: 1 month
Relnotes: Yes
Sponsored by: The FreeBSD Foundation
Some notable changes, from upstream's release notes:
- sshd(8): Remove support for obsolete "host/port" syntax.
- ssh(1): When prompting whether to record a new host key, accept the key
fingerprint as a synonym for "yes".
- ssh-keygen(1): when acting as a CA and signing certificates with an RSA
key, default to using the rsa-sha2-512 signature algorithm.
- ssh(1), sshd(8), ssh-keygen(1): this release removes the "ssh-rsa"
(RSA/SHA1) algorithm from those accepted for certificate signatures.
- ssh-sk-helper(8): this is a new binary. It is used by the FIDO/U2F
support to provide address-space isolation for token middleware
libraries (including the internal one).
- ssh(1): this release enables UpdateHostkeys by default subject to some
conservative preconditions.
- scp(1): this release changes the behaviour of remote to remote copies
(e.g. "scp host-a:/path host-b:") to transfer through the local host
by default.
- scp(1): experimental support for transfers using the SFTP protocol as
a replacement for the venerable SCP/RCP protocol that it has
traditionally used.
Additional integration work is needed to support FIDO/U2F in the base
system.
Deprecation Notice
------------------
OpenSSH will disable the ssh-rsa signature scheme by default in the
next release.
Reviewed by: imp
MFC after: 1 month
Relnotes: Yes
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D29985
This completely removes client-side support for the SSH 1 protocol,
which was already disabled in 12 but is still enabled in 11. For that
reason, we will not be able to merge 7.6p1 or newer back to 11.
I have worked hard to reduce diffs against the vendor branch. One
notable change in that respect is that we no longer prefer DSA over
RSA - the reasons for doing so went away years ago. This may cause
some surprises, as ssh will warn about unknown host keys even for
hosts whose keys haven't changed.
MFC after: 6 weeks
