Commit 71fabd5e authored by George Anzinger's avatar George Anzinger Committed by Linus Torvalds
Browse files

[PATCH] sigaction should clear all signals on SIG_IGN, not just < 32 



While rooting aroung in the signal code trying to understand how to fix the
SIG_IGN ploy (set sig handler to SIG_IGN and flood system with high speed
repeating timers) I came across what, I think, is a problem in sigaction()
in that when processing a SIG_IGN request it flushes signals from 1 to
SIGRTMIN and leaves the rest.  Attempt to fix this.

Signed-off-by: default avatarGeorge Anzinger <george@mvista.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: default avatarAdrian Bunk <bunk@stusta.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent b5f545c8

include/linux/signal.h

+17 −0
Original line number Diff line number Diff line
@@ -94,6 +94,23 @@ static inline int sigfindinword(unsigned long word) 


#endif /* __HAVE_ARCH_SIG_BITOPS */



static inline int sigisemptyset(sigset_t *set)

{

	extern void _NSIG_WORDS_is_unsupported_size(void);

	switch (_NSIG_WORDS) {

	case 4:

		return (set->sig[3] | set->sig[2] |

			set->sig[1] | set->sig[0]) == 0;

	case 2:

		return (set->sig[1] | set->sig[0]) == 0;

	case 1:

		return set->sig[0] == 0;

	default:

		_NSIG_WORDS_is_unsupported_size();

		return 0;

	}

}



#define sigmask(sig)	(1UL << ((sig) - 1))



#ifndef __HAVE_ARCH_SIG_SETOPS

kernel/signal.c

+32 −2
Original line number Diff line number Diff line
@@ -620,6 +620,33 @@ void signal_wake_up(struct task_struct *t, int resume) 
		kick_process(t);

}



/*

 * Remove signals in mask from the pending set and queue.

 * Returns 1 if any signals were found.

 *

 * All callers must be holding the siglock.

 *

 * This version takes a sigset mask and looks at all signals,

 * not just those in the first mask word.

 */

static int rm_from_queue_full(sigset_t *mask, struct sigpending *s)

{

	struct sigqueue *q, *n;

	sigset_t m;



	sigandsets(&m, mask, &s->signal);

	if (sigisemptyset(&m))

		return 0;



	signandsets(&s->signal, &s->signal, mask);

	list_for_each_entry_safe(q, n, &s->list, list) {

		if (sigismember(mask, q->info.si_signo)) {

			list_del_init(&q->list);

			__sigqueue_free(q);

		}

	}

	return 1;

}

/*

 * Remove signals in mask from the pending set and queue.

 * Returns 1 if any signals were found.
@@ -2408,6 +2435,7 @@ int 
do_sigaction(int sig, const struct k_sigaction *act, struct k_sigaction *oact)

{

	struct k_sigaction *k;

	sigset_t mask;



	if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))

		return -EINVAL;
@@ -2455,9 +2483,11 @@ do_sigaction(int sig, const struct k_sigaction *act, struct k_sigaction *oact) 
			*k = *act;

			sigdelsetmask(&k->sa.sa_mask,

				      sigmask(SIGKILL) | sigmask(SIGSTOP));

			rm_from_queue(sigmask(sig), &t->signal->shared_pending);

			sigemptyset(&mask);

			sigaddset(&mask, sig);

			rm_from_queue_full(&mask, &t->signal->shared_pending);

			do {

				rm_from_queue(sigmask(sig), &t->pending);

				rm_from_queue_full(&mask, &t->pending);

				recalc_sigpending_tsk(t);

				t = next_thread(t);

			} while (t != current);

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