sshd blocks SIGALRM

[Loic Domaigne]

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

As a result, any descendent processes shall inherit this mask. The bad news
is that some commands rely on SIGALRM being unmasked, e.g. those invoking
alarm() or similar. If those commands are started from a "ssh shell", then
they won't work correctly (e.g. never times out). That's really annoying. 

Do you have an idea where the problem lies?
Below you shall find the relevant information about the system. 

Thanks in advance! 
Loic. 

******************* System information ******************

* Hardware:
HP Proliant, intel PIII 1.4Ghz

* SuSE release: 
SuSE Professional v9.2

* uname -a:
Linux mucltpa04 2.6.8-24-smp #1 SMP Wed Oct 6 09:16:23 UTC 2004 i686 i686
i386 GNU/Linux

* openssh
based on the following RPMs:
openssh-3.9p1-3
openssh-askpass-3.9p1-3

* let me know if you need more information

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