From 06f1631a1671bce2d59d58cb1debdf23e1803ebf Mon Sep 17 00:00:00 2001 From: Oleg Nesterov <oleg@redhat.com> Date: Wed, 23 Sep 2009 15:57:01 -0700 Subject: [PATCH] signals: send_sigio: use do_send_sig_info() to avoid check_kill_permission() 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: Oleg 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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> --- fs/fcntl.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/fcntl.c b/fs/fcntl.c index ae413086db978..50a9889932625 100644 --- a/fs/fcntl.c +++ b/fs/fcntl.c @@ -461,11 +461,11 @@ static void send_sigio_to_task(struct task_struct *p, else si.si_band = band_table[reason - POLL_IN]; si.si_fd = fd; - if (!group_send_sig_info(signum, &si, p)) + if (!do_send_sig_info(signum, &si, p, true)) break; /* fall-through: fall back on the old plain SIGIO signal */ case 0: - group_send_sig_info(SIGIO, SEND_SIG_PRIV, p); + do_send_sig_info(SIGIO, SEND_SIG_PRIV, p, true); } } -- GitLab