- Update from 8.7p1 to 8.8p1
- Update of rootfile not required
- Changelog
OpenSSH 8.8p1
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
sshd(8) from OpenSSH 6.2 through 8.7 failed to correctly initialise
supplemental groups when executing an AuthorizedKeysCommand or
AuthorizedPrincipalsCommand, where a AuthorizedKeysCommandUser or
AuthorizedPrincipalsCommandUser directive has been set to run the
command as a different user. Instead these commands would inherit
the groups that sshd(8) was started with.
Depending on system configuration, inherited groups may allow
AuthorizedKeysCommand/AuthorizedPrincipalsCommand helper programs to
gain unintended privilege.
Neither AuthorizedKeysCommand nor AuthorizedPrincipalsCommand are
enabled by default in sshd_config(5).
Potentially-incompatible changes
This release disables RSA signatures using the SHA-1 hash algorithm
by default. This change has been made as the SHA-1 hash algorithm is
cryptographically broken, and it is possible to create chosen-prefix
hash collisions for <USD$50K [1]
For most users, this change should be invisible and there is
no need to replace ssh-rsa keys. OpenSSH has supported RFC8332
RSA/SHA-256/512 signatures since release 7.2 and existing ssh-rsa keys
will automatically use the stronger algorithm where possible.
Changes since OpenSSH 8.7p1
This release is motivated primarily by the above deprecation and
security fix.
New features
* ssh(1): allow the ssh_config(5) CanonicalizePermittedCNAMEs
directive to accept a "none" argument to specify the default
behaviour.
Bugfixes
* scp(1): when using the SFTP protocol, continue transferring files
after a transfer error occurs, better matching original scp/rcp
behaviour.
* ssh(1): fixed a number of memory leaks in multiplexing,
* ssh-keygen(1): avoid crash when using the -Y find-principals
command.
* A number of documentation and manual improvements, including
bz#3340, PR139, PR215, PR241, PR257
Portability
* ssh-agent(1): on FreeBSD, use procctl to disable ptrace(2)
* ssh(1)/sshd(8): some fixes to the pselect(2) replacement
compatibility code. bz#3345
Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>
This reverts commit a9fb87809e.
This prevents the SSH configuration being parsed by the web user
interface.
Reported-by: Arne Fitzenreiter <arne_f@ipfire.org>
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
This file does not have to be readable by anybody else than the user
running an OpenSSH server. While it does not really contain confidential
information, exposing it to the rest of the world makes no sense either.
This will silence a Lynis warning. :-)
Signed-off-by: Peter Müller <peter.mueller@ipfire.org>
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
- Update from 8.5p1 to 8.6p1
- Update of rootfile not needed
- Changelog
Future deprecation notice
It is now possible[1] to perform chosen-prefix attacks against the
SHA-1 algorithm for less than USD$50K.
In the SSH protocol, the "ssh-rsa" signature scheme uses the SHA-1
hash algorithm in conjunction with the RSA public key algorithm.
OpenSSH will disable this signature scheme by default in the near
future.
Note that the deactivation of "ssh-rsa" signatures does not necessarily
require cessation of use for RSA keys. In the SSH protocol, keys may be
capable of signing using multiple algorithms. In particular, "ssh-rsa"
keys are capable of signing using "rsa-sha2-256" (RSA/SHA256),
"rsa-sha2-512" (RSA/SHA512) and "ssh-rsa" (RSA/SHA1). Only the last of
these is being turned off by default.
This algorithm is unfortunately still used widely despite the
existence of better alternatives, being the only remaining public key
signature algorithm specified by the original SSH RFCs that is still
enabled by default.
The better alternatives include:
* The RFC8332 RSA SHA-2 signature algorithms rsa-sha2-256/512. These
algorithms have the advantage of using the same key type as
"ssh-rsa" but use the safe SHA-2 hash algorithms. These have been
supported since OpenSSH 7.2 and are already used by default if the
client and server support them.
* The RFC8709 ssh-ed25519 signature algorithm. It has been supported
in OpenSSH since release 6.5.
* The RFC5656 ECDSA algorithms: ecdsa-sha2-nistp256/384/521. These
have been supported by OpenSSH since release 5.7.
To check whether a server is using the weak ssh-rsa public key
algorithm, for host authentication, try to connect to it after
removing the ssh-rsa algorithm from ssh(1)'s allowed list:
ssh -oHostKeyAlgorithms=-ssh-rsa user@host
If the host key verification fails and no other supported host key
types are available, the server software on that host should be
upgraded.
OpenSSH recently enabled the UpdateHostKeys option by default to assist
the client by automatically migrating to better algorithms.
[1] "SHA-1 is a Shambles: First Chosen-Prefix Collision on SHA-1 and
Application to the PGP Web of Trust" Leurent, G and Peyrin, T
(2020) https://eprint.iacr.org/2020/014.pdf
Security
* sshd(8): OpenSSH 8.5 introduced the LogVerbose keyword. When this
option was enabled with a set of patterns that activated logging
in code that runs in the low-privilege sandboxed sshd process, the
log messages were constructed in such a way that printf(3) format
strings could effectively be specified the low-privilege code.
An attacker who had sucessfully exploited the low-privilege
process could use this to escape OpenSSH's sandboxing and attack
the high-privilege process. Exploitation of this weakness is
highly unlikely in practice as the LogVerbose option is not
enabled by default and is typically only used for debugging. No
vulnerabilities in the low-privilege process are currently known
to exist.
Thanks to Ilja Van Sprundel for reporting this bug.
Changes since OpenSSH 8.5
This release contains mostly bug fixes.
New features
* sftp-server(8): add a new limits@openssh.com protocol extension
that allows a client to discover various server limits, including
maximum packet size and maximum read/write length.
* sftp(1): use the new limits@openssh.com extension (when available)
to select better transfer lengths in the client.
* sshd(8): Add ModuliFile keyword to sshd_config to specify the
location of the "moduli" file containing the groups for DH-GEX.
* unit tests: Add a TEST_SSH_ELAPSED_TIMES environment variable to
enable printing of the elapsed time in seconds of each test.
Bugfixes
* ssh_config(5), sshd_config(5): sync CASignatureAlgorithms lists in
manual pages with the current default. GHPR174
* ssh(1): ensure that pkcs11_del_provider() is called before exit.
GHPR234
* ssh(1), sshd(8): fix problems in string->argv conversion. Multiple
backslashes were not being dequoted correctly and quoted space in
the middle of a string was being incorrectly split. GHPR223
* ssh(1): return non-zero exit status when killed by signal; bz#3281
* sftp-server(8): increase maximum SSH2_FXP_READ to match the maximum
packet size. Also handle zero-length reads that are not explicitly
banned by the spec.
Portability
* sshd(8): don't mistakenly exit on transient read errors on the
network socket (e.g. EINTR, EAGAIN); bz3297
* Create a dedicated contrib/gnome-ssk-askpass3.c source instead of
building it from the same file as used for GNOME2. Use the GNOME3
gdk_seat_grab() to manage keyboard/mouse/server grabs for better
compatibility with Wayland.
* Fix portability build errors bz3293 bz3292 bz3291 bz3278
* sshd(8): soft-disallow the fstatat64 syscall in the Linux
seccomp-bpf sandbox. bz3276
* unit tests: enable autoopt and misc unit tests that were
previously skipped
Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
- Update Openssh from 8.4p1 to 8.5p1
- rootfiles not changed
- ssh access by keys tested with 8.5p1 and successfully worked
- Full Release notes can be read at https://www.openssh.com/releasenotes.html
- Future deprecation notice
It is now possible[1] to perform chosen-prefix attacks against the
SHA-1 algorithm for less than USD$50K.
In the SSH protocol, the "ssh-rsa" signature scheme uses the SHA-1
hash algorithm in conjunction with the RSA public key algorithm.
OpenSSH will disable this signature scheme by default in the near
future.
Note that the deactivation of "ssh-rsa" signatures does not necessarily
require cessation of use for RSA keys. In the SSH protocol, keys may be
capable of signing using multiple algorithms. In particular, "ssh-rsa"
keys are capable of signing using "rsa-sha2-256" (RSA/SHA256),
"rsa-sha2-512" (RSA/SHA512) and "ssh-rsa" (RSA/SHA1). Only the last of
these is being turned off by default.
- Checked if the weak ssh-rsa public key algorithm was being used with
openssh8.4p1 by running
ssh -oHostKeyAlgorithms=-ssh-rsa user@host
host verification was successful with no issue so IPFire will not be
affected by this deprecation when it happens
- Potentially-incompatible changes
* ssh(1), sshd(8): this release changes the first-preference signature
algorithm from ECDSA to ED25519.
This did not affect my use of ssh login but I use ED25519 as the only
key algorithm that I use. It might be good to get it tested by
someone who has ECDSA and ED25519 keys and prefers ECDSA
Remaining changes don't look likely to affect IPFire users
- Bugfixes
* ssh(1): Prefix keyboard interactive prompts with "(user@host)" to
make it easier to determine which connection they are associated
with in cases like scp -3, ProxyJump, etc. bz#3224
* sshd(8): fix sshd_config SetEnv directives located inside Match
blocks. GHPR201
* ssh(1): when requesting a FIDO token touch on stderr, inform the
user once the touch has been recorded.
* ssh(1): prevent integer overflow when ridiculously large
ConnectTimeout values are specified, capping the effective value
(for most platforms) at 24 days. bz#3229
* ssh(1): consider the ECDSA key subtype when ordering host key
algorithms in the client.
* ssh(1), sshd(8): rename the PubkeyAcceptedKeyTypes keyword to
PubkeyAcceptedAlgorithms. The previous name incorrectly suggested
that it control allowed key algorithms, when this option actually
specifies the signature algorithms that are accepted. The previous
name remains available as an alias. bz#3253
* ssh(1), sshd(8): similarly, rename HostbasedKeyTypes (ssh) and
HostbasedAcceptedKeyTypes (sshd) to HostbasedAcceptedAlgorithms.
* sftp-server(8): add missing lsetstat@openssh.com documentation
and advertisement in the server's SSH2_FXP_VERSION hello packet.
* ssh(1), sshd(8): more strictly enforce KEX state-machine by
banning packet types once they are received. Fixes memleak caused
by duplicate SSH2_MSG_KEX_DH_GEX_REQUEST (oss-fuzz #30078).
* sftp(1): allow the full range of UIDs/GIDs for chown/chgrp on 32bit
platforms instead of being limited by LONG_MAX. bz#3206
* Minor man page fixes (capitalization, commas, etc.) bz#3223
* sftp(1): when doing an sftp recursive upload or download of a
read-only directory, ensure that the directory is created with
write and execute permissions in the interim so that the transfer
can actually complete, then set the directory permission as the
final step. bz#3222
* ssh-keygen(1): document the -Z, check the validity of its argument
earlier and provide a better error message if it's not correct.
bz#2879
* ssh(1): ignore comments at the end of config lines in ssh_config,
similar to what we already do for sshd_config. bz#2320
* sshd_config(5): mention that DisableForwarding is valid in a
sshd_config Match block. bz3239
* sftp(1): fix incorrect sorting of "ls -ltr" under some
circumstances. bz3248.
* ssh(1), sshd(8): fix potential integer truncation of (unlikely)
timeout values. bz#3250
* ssh(1): make hostbased authentication send the signature algorithm
in its SSH2_MSG_USERAUTH_REQUEST packets instead of the key type.
This make HostbasedAcceptedAlgorithms do what it is supposed to -
filter on signature algorithm and not key type.
Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>
Reviewed-by: Peter Müller <peter.mueller@ipfire.org>
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
glibc calls clock_nanosleep_time64 syscall even if it not defined in
the headers for this arch and the seccomp filter kills the process
with because an unknown syscall.
Signed-off-by: Arne Fitzenreiter <arne_f@ipfire.org>
Includes various security fixes:
* sshd(8): Mitigate a potential denial-of-service attack against
the system's crypt(3) function via sshd(8). An attacker could
send very long passwords that would cause excessive CPU use in
crypt(3). sshd(8) now refuses to accept password authentication
requests of length greater than 1024 characters. Independently
reported by Tomas Kuthan (Oracle), Andres Rojas and Javier Nieto.
* sshd(8): Mitigate timing differences in password authentication
that could be used to discern valid from invalid account names
when long passwords were sent and particular password hashing
algorithms are in use on the server. CVE-2016-6210, reported by
EddieEzra.Harari at verint.com
* ssh(1), sshd(8): Fix observable timing weakness in the CBC padding
oracle countermeasures. Reported by Jean Paul Degabriele, Kenny
Paterson, Torben Hansen and Martin Albrecht. Note that CBC ciphers
are disabled by default and only included for legacy compatibility.
* ssh(1), sshd(8): Improve operation ordering of MAC verification for
Encrypt-then-MAC (EtM) mode transport MAC algorithms to verify the
MAC before decrypting any ciphertext. This removes the possibility
of timing differences leaking facts about the plaintext, though no
such leakage has been observed. Reported by Jean Paul Degabriele,
Kenny Paterson, Torben Hansen and Martin Albrecht.
* sshd(8): (portable only) Ignore PAM environment vars when
UseLogin=yes. If PAM is configured to read user-specified
environment variables and UseLogin=yes in sshd_config, then a
hostile local user may attack /bin/login via LD_PRELOAD or
similar environment variables set via PAM. CVE-2015-8325,
found by Shayan Sadigh.
Fixes: #11160
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
Previous we had not configured it so the ssh default order was used.
Now we define it to disable dsa so we had to give the correct order but
in the example cfg rsa is prefered.
Signed-off-by: Arne Fitzenreiter <arne_f@ipfire.org>
