• Oleg Nesterov's avatar
    signals: send_sigio: use do_send_sig_info() to avoid check_kill_permission() · 06f1631a
    Oleg Nesterov authored
    group_send_sig_info()->check_kill_permission() assumes that current is the
    sender and uses current_cred().
    This is not true in send_sigio_to_task() case.  From the security pov the
    sender is not current, but the task which did fcntl(F_SETOWN), that is why
    we have sigio_perm() which uses the right creds to check.
    Fortunately, send_sigio() always sends either SEND_SIG_PRIV or
    SI_FROMKERNEL() signal, so check_kill_permission() does nothing.  But
    still it would be tidier to avoid this bogus security check and save a
    couple of cycles.
    Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
    Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
    Cc: stephane eranian <eranian@googlemail.com>
    Cc: Ingo Molnar <mingo@elte.hu>
    Cc: Roland McGrath <roland@redhat.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
fcntl.c 14 KB