Relax si_code check in rt_sigqueueinfo and rt_tgsigqueueinfo
commit 243b422af9ea9af4ead07a8ad54c90d4f9b6081a upstream
Commit da48524eb206 ("Prevent rt_sigqueueinfo and rt_tgsigqueueinfo
from spoofing the signal code") made the check on si_code too strict.
There are several legitimate places where glibc wants to queue a
negative si_code different from SI_QUEUE:
- This was first noticed with glibc's aio implementation, which wants
to queue a signal with si_code SI_ASYNCIO; the current kernel
causes glibc's tst-aio4 test to fail because rt_sigqueueinfo()
fails with EPERM.
- Further examination of the glibc source shows that getaddrinfo_a()
wants to use SI_ASYNCNL (which the kernel does not even define).
The timer_create() fallback code wants to queue signals with SI_TIMER.
As suggested by Oleg Nesterov <firstname.lastname@example.org>, loosen the check to
forbid only the problematic SI_TKILL case.
Reported-by: Klaus Dittrich <email@example.com>
Acked-by: Julien Tinnes <firstname.lastname@example.org>
Signed-off-by: Roland Dreier <email@example.com>
Signed-off-by: Linus Torvalds <firstname.lastname@example.org>
Tested-by: Krzysztof Mazur <email@example.com>
Signed-off-by: Willy Tarreau <firstname.lastname@example.org>
1 file changed