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author | Roland Dreier <roland@purestorage.com> | 2011-03-28 14:13:35 -0700 |
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committer | Willy Tarreau <w@1wt.eu> | 2012-10-06 00:35:00 +0200 |
commit | e294a2074f0059de7c69b30fe3048fe61f971b83 (patch) | |
tree | 10dd8fbd6e6e34d8e2a1b67b57ac18ec20522a6b | |
parent | 82582b970d04ad4bcfaa9d3f9c3c256619fd889f (diff) | |
download | linux-2.4-e294a2074f0059de7c69b30fe3048fe61f971b83.tar.gz |
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 <oleg@redhat.com>, loosen the check to
forbid only the problematic SI_TKILL case.
Reported-by: Klaus Dittrich <kladit@arcor.de>
Acked-by: Julien Tinnes <jln@google.com>
Cc: <stable@kernel.org>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Tested-by: Krzysztof Mazur <krzysiek@podlesie.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
-rw-r--r-- | kernel/signal.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/signal.c b/kernel/signal.c index b368505a7b22fc..461885de3ff24d 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -1076,7 +1076,7 @@ sys_rt_sigqueueinfo(int pid, int sig, siginfo_t *uinfo) /* Not even root can pretend to send signals from the kernel. * Nor can they impersonate a kill()/tgkill(), which adds source info. */ - if (info.si_code != SI_QUEUE) { + if (info.si_code >= 0 || info.si_code == SI_TKILL) { /* We used to allow any < 0 si_code */ return -EPERM; } |