PubkeyAcceptedKeyTypes with + in Match block not working correctly.

[Andy Bradford]

Hello,

I notice that if I configure sshd_config with:

PubkeyAcceptedKeyTypes +ssh-dss

Everything works as expected and the algorithm is appended to the
default list, but if I place that same option in a Match block it does
not extend the setting, but instead replaces it with a literal string of
``+ssh-dss'' which effectively disables all algorithms.

# tail -2 /etc/ssh/sshd_config
Match Address 192.168.1.0/24
PubkeyAcceptedKeyTypes +ssh-dss

# sshd -T -C user=tester,host=example.dom,addr=192.168.1.1,laddr=192.168.1.2,lport=22 | grep pubkey
pubkeyauthentication yes
pubkeyacceptedkeytypes +ssh-dss

I found a similar bug mentioned here regarding HostkeyAlgorithms but as
far as I can tell the fix didn't extend to cover the above mentioned
scenario:

http://marc.info/?l=openssh-unix-dev&m=144019508104294&w=2

Does this need to go reported also to bugs@ or is this list sufficient?

Thanks,

Andy

[Damien Miller]

Post by Andy Bradford
Hello,
PubkeyAcceptedKeyTypes +ssh-dss
Everything works as expected and the algorithm is appended to the
default list, but if I place that same option in a Match block it does
not extend the setting, but instead replaces it with a literal string of
``+ssh-dss'' which effectively disables all algorithms.

This was fixed in commit ed08510d38 and will be in openssh-7.2, which
is due real soon now (~weeks).

https://anongit.mindrot.org/openssh.git/commit/?id=ed08510d38

-d