sshd blocks SIGALRM

[Damien Miller]

Loic Domaigne wrote:
> Gidday everbody, 
> 
> We have just found an interesting issue regarding the sshd daemon on our
> SuSE system. For some reasons, the /usr/sbin/sshd process blocks SIGALRM as
> shown in the /proc/pid/status:
> 
> $ cat /proc/`cat /var/run/sshd.init.pid`/status
> Name:   sshd
> State:  S (sleeping)
> SleepAVG:       0%
> [...]
> SigPnd: 0000000000000000
> ShdPnd: 0000000000000000
> SigBlk: 0000000000002000  <-- SIGALRM is blocked
> SigIgn: 0000000000001000

you are looking at the wrong thing. You should look at the signal masks
of the descendant processes. We clear the ALRM handler in the parent
after accept().