linux-kernel - [PATCH 2/2] posix-timers: fix RLIMIT_CPU && setitimer(CPUCLOCK

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 27 Mar 2009 01:06:10 +0100
From:	Oleg Nesterov <oleg@...hat.com>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	Peter Lojkin <ia6432@...ox.ru>,
	Peter Zijlstra <peterz@...radead.org>,
	Roland McGrath <roland@...hat.com>,
	linux-kernel@...r.kernel.org, stable@...nel.org
Subject: [PATCH 2/2] posix-timers: fix RLIMIT_CPU &&
	setitimer(CPUCLOCK_PROF)

update_rlimit_cpu() tries to optimize out set_process_cpu_timer() in case
when we already have CPUCLOCK_PROF timer which should expire first. But it
uses cputime_lt() instead of cputime_gt().

Test case:

	int main(void)
	{
		struct itimerval it = {
			.it_value = { .tv_sec = 1000 },
		};

		assert(!setitimer(ITIMER_PROF, &it, NULL));

		struct rlimit rl = {
			.rlim_cur = 1,
			.rlim_max = 1,
		};

		assert(!setrlimit(RLIMIT_CPU, &rl));

		for (;;)
			;

		return 0;
	}

Without this patch, the task is not killed as RLIMIT_CPU demands.

Signed-off-by: Oleg Nesterov <oleg@...hat.com>

--- 6.29/kernel/posix-cpu-timers.c~2_UPDATE_RLIM	2009-03-23 18:13:57.000000000 +0100
+++ 6.29/kernel/posix-cpu-timers.c	2009-03-27 00:45:31.000000000 +0100
@@ -18,7 +18,7 @@ void update_rlimit_cpu(unsigned long rli
 
 	cputime = secs_to_cputime(rlim_new);
 	if (cputime_eq(current->signal->it_prof_expires, cputime_zero) ||
-	    cputime_lt(current->signal->it_prof_expires, cputime)) {
+	    cputime_gt(current->signal->it_prof_expires, cputime)) {
 		spin_lock_irq(&current->sighand->siglock);
 		set_process_cpu_timer(current, CPUCLOCK_PROF, &cputime, NULL);
 		spin_unlock_irq(&current->sighand->siglock);

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/