This adds a protocol extension to improve the integrity of the SSH
transport protocol, particular in and around the initial key exchange
(KEX) phase.
Full details of the extension are in the PROTOCOL file.
OpenBSD-Commit-ID: 2a66ac962f0a630d7945fee54004ed9e9c439f14
Approved by: so (implicit)
Obtained from: https://anongit.mindrot.org/openssh.git/patch/?id=1edb00c58f8a6875fad6a497aa2bacf37f9e6cd5
Security: CVE-2023-48795
Excerpts from the release notes:
Potentially incompatible changes
--------------------------------
* ssh-keygen(1): generate Ed25519 keys by default.
[NOTE: This change was already merged into FreeBSD.]
* sshd(8): the Subsystem directive now accurately preserves quoting of
subsystem commands and arguments.
New features
------------
* ssh(1): add keystroke timing obfuscation to the client.
* ssh(1), sshd(8): Introduce a transport-level ping facility.
* sshd(8): allow override of Sybsystem directives in sshd Match blocks.
Full release notes at https://www.openssh.com/txt/release-9.5
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.
the bandwidth of long fat pipes (i.e. 100Mbps+ trans-oceanic or
trans-continental links). Bandwidth-delay products up to 64MB are
supported.
Also add support (not compiled by default) for the None cypher. The
None cypher can only be enabled on non-interactive sessions (those
without a pty where -T was not used) and must be enabled in both
the client and server configuration files and on the client command
line. Additionally, the None cypher will only be activated after
authentication is complete. To enable the None cypher you must add
-DNONE_CIPHER_ENABLED to CFLAGS via the make command line or in
/etc/make.conf.
This code is a style(9) compliant version of these features extracted
from the patches published at:
http://www.psc.edu/networking/projects/hpn-ssh/
Merging this patch has been a collaboration between me and Bjoern.
Reviewed by: bz
Approved by: re (kib), des (maintainer)
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
- sshd fails to set TERM correctly.
- privilege separation may break PAM and is currently turned off.
- man pages have not yet been updated
I will have these issues resolved, and privilege separation turned on by
default, in time for DP2.
Sponsored by: DARPA, NAI Labs
