Call for testing: OpenSSH 8.1
djm at mindrot.org
Tue Oct 1 21:33:43 AEST 2019
OpenSSH 8.1p1 is almost ready for release, so we would appreciate testing
on as many platforms and systems as possible. This is a bugfix release.
Snapshot releases for portable OpenSSH are available from
The OpenBSD version is available in CVS HEAD:
Portable OpenSSH is also available via git using the
instructions at http://www.openssh.com/portable.html#cvs
At https://anongit.mindrot.org/openssh.git/ or via a mirror at Github:
Running the regression tests supplied with Portable OpenSSH does not
require installation and is a simply:
$ ./configure && make tests
Live testing on suitable non-production systems is also appreciated.
Please send reports of success or failure to
openssh-unix-dev at mindrot.org. Security bugs should be reported
directly to openssh at openssh.com.
Below is a summary of changes. More detail may be found in the ChangeLog
in the portable OpenSSH tarballs.
Thanks to the many people who contributed to this release.
* ssh(1), sshd(8), ssh-agent(1): add protection for private keys at
rest in RAM against speculation and memory sidechannel attacks like
Spectre, Meltdown and Rambleed. This release encrypts private keys
when they are not in use with a symmetic key that is derived from a
relatively large "prekey" consisting of random data (currently 16KB).
Attackers must recover the entire prekey before they are able to
decrypt the protected private keys, but the current generation of
attacks have bit error rates that render this unlikely to be
This release includes one change that may affect existing
* ssh-keygen(1): when acting as a CA and signing certificates with
an RSA key, default to using the rsa-sha2-512 signature algorithm.
Certificates signed by RSA keys will therefore be incompatible
with OpenSSH versions prior to 7.2 unless the default is
overridden (using "ssh-keygen -t ssh-rsa -s ...").
Changes since OpenSSH 8.0
This release is focused on bugfixing.
* ssh(1): Allow %n to be expanded in ProxyCommand strings
* ssh(1), sshd(8): Allow prepending a list of algorithms to the
default set by starting the list with the '^' character, E.g.
* ssh-keygen(1): add an experimental lightweight signature and
verification ability. Signatures may be made using regular ssh keys
held on disk or stored in a ssh-agent and verified against an
authorized_keys-like list of allowed keys. Signatures embed a
namespace that prevents confusion and attacks between different
usage domains (e.g. files vs email).
* ssh-keygen(1): print key comment when extracting publc key from a
private key. bz#3052
* ssh-keygen(1): accept the verbose flag when searching for host keys
in known hosts (i.e. "ssh-keygen -vF host") to print the matching
host's random-art signature too. bz#3003
* All: support PKCS8 as an optional format for storage of private
keys to disk. The OpenSSH native key format remains the default,
but PKCS8 is a superior format to PEM if interoperability with
non-OpenSSH software is required, as it may use a less insecure
key derivation function than PEM's.
* ssh(1): if a PKCS#11 token returns no keys then try to login and
refetch them. Based on patch from Jakub Jelen; bz#2430
* ssh(1): produce a useful error message if the user's shell is set
incorrectly during "match exec" processing. bz#2791
* sftp(1): allow the maximimum uint32 value for the argument passed
to -b which allows better error messages from later validation.
* ssh(1): avoid pledge sandbox violations in some combinations of
remote forwarding, connection multiplexing and ControlMaster.
* ssh-keyscan(1): include SHA2-variant RSA key algorithms in KEX
proposal; allows ssh-keyscan to harvest keys from servers that
disable olde SHA1 ssh-rsa. bz#3029
* sftp(1): print explicit "not modified" message if a file was
requested for resumed download but was considered already complete.
* sftp(1): fix a typo and make <esc><right> move right to the
closest end of a word just like <esc><left> moves left to the
closest beginning of a word.
* sshd(8): cap the number of permiopen/permitlisten directives
allowed to appear on a single authorized_keys line.
* All: fix a number of memory leaks (one-off or on exit paths).
* Regression tests: a number of fixes and improvments, including
fixes to the interop tests, adding the ability to run most tests
on builds that disable OpenSSL support, better support for running
tests under Valgrind and a number of bugfixes.
* ssh(1), sshd(8): check for convtime() refusing to accept times that
resolve to LONG_MAX Reported by Kirk Wolf bz2977
* ssh(1): slightly more instructive error message when the user
specifies multiple -J options on the commandline. bz3015
* ssh-agent(1): process agent requests for RSA certificate private
keys using correct signature algorithm when requested. bz3016
* sftp(1): check for user at host when parsing sftp target. This
allows email@example.com to work without a path. bz#2999
* sshd(8): enlarge format buffer size for certificate serial
number so the log message can record any 64-bit integer without
* sshd(8): for PermitOpen violations add the remote host and port to
be able to more easily ascertain the source of the request. Add the
same logging for PermitListen violations which where not previously
logged at all.
* scp(1), sftp(1): use the correct POSIX format style for left
justification for the transfer progress meter. bz#3002
* sshd(8) when examining a configureation using sshd -T, assume any
attibute not provided by -C does not match, which allows it to work
when sshd_config contains a Match directive with or without -C.
* ssh(1), ssh-keygen(1): downgrade PKCS#11 "provider returned no
slots" warning from log level error to debug. This is common when
attempting to enumerate keys on smartcard readers with no cards
plugged in. bz#3058
* ssh(1), ssh-keygen(1): do not unconditionally log in to PKCS#11
tokens. Avoids spurious PIN prompts for keys not selected for
authentication in ssh(1) and when listing public keys available in
a token using ssh-keygen(1). bz#3006
* ssh(1): fix SIGWINCH delivery of Solaris for multiplexed sessions
* ssh(1), sshd(8): fix typo that prevented detection of Linux VRF
* sshd(8): add no-op implementation of pam_putenv to avoid build
breakage on platforms where the PAM implementation lacks this
function (e.g. HP-UX). bz#3008
* sftp-server(8): fix Solaris privilege sandbox from preventing
the legacy sftp rename operation from working (was refusing to
allow hard links to files owned by other users). bz#3036
* All: add a proc_pidinfo()-based closefrom() for OS X to avoid
the need to brute-force close all high-numbered file descriptors.
* sshd(8): in the Linux seccomp-bpf sandbox, allow mprotect(2) with
PROT_(READ|WRITE|NONE) only. This syscall is used by some hardened
heap allocators. Github PR#142
* sshd(8): in the Linux seccomp-bpf sandbox, allow the s390-specific
ioctl for ecc hardware support.
* All: use "doc" man page format if the mandoc(1) tool is present on
the system. Previously configure would not select the "doc" man
page format if mandoc was present but nroff was not.
* sshd(8): don't install duplicate STREAMS modules on Solaris; check
if STREAMS modules are already installed on a pty before installing
since when compiling with XPG>=4 they will likely be installed
already. Prevents hangs and duplicate lines on the terminal.
bz#2945 and bz#2998,
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