signals: don't abuse __flush_signals() in selinux_bprm_committed_creds()
selinux_bprm_committed_creds()->__flush_signals() is not right, we
shouldn't clear TIF_SIGPENDING unconditionally. There can be other
reasons for signal_pending(): freezing(), JOBCTL_PENDING_MASK, and
potentially more.
Also change this code to check fatal_signal_pending() rather than
SIGNAL_GROUP_EXIT, it looks a bit better.
Now we can kill __flush_signals() before it finds another buggy user.
Note: this code looks racy, we can flush a signal which was sent after
the task SID has been updated.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Paul Moore <pmoore@redhat.com>
diff --git a/kernel/signal.c b/kernel/signal.c
index d51c5dd..d497250 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -414,21 +414,16 @@
}
/*
- * Flush all pending signals for a task.
+ * Flush all pending signals for this kthread.
*/
-void __flush_signals(struct task_struct *t)
-{
- clear_tsk_thread_flag(t, TIF_SIGPENDING);
- flush_sigqueue(&t->pending);
- flush_sigqueue(&t->signal->shared_pending);
-}
-
void flush_signals(struct task_struct *t)
{
unsigned long flags;
spin_lock_irqsave(&t->sighand->siglock, flags);
- __flush_signals(t);
+ clear_tsk_thread_flag(t, TIF_SIGPENDING);
+ flush_sigqueue(&t->pending);
+ flush_sigqueue(&t->signal->shared_pending);
spin_unlock_irqrestore(&t->sighand->siglock, flags);
}