• Roland Dreier's avatar
    Relax si_code check in rt_sigqueueinfo and rt_tgsigqueueinfo · 243b422a
    Roland Dreier authored
    Commit da48524e ("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: default avatarKlaus Dittrich <kladit@arcor.de>
    Acked-by: default avatarJulien Tinnes <jln@google.com>
    Cc: <stable@kernel.org>
    Signed-off-by: default avatarRoland Dreier <roland@purestorage.com>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    243b422a
signal.c 70.1 KB