| Date | Mon, 04 Mar 2013 03:38:10 +0000 | From | Ben Hutchings <> | Subject | [ 063/153] posix-cpu-timers: Fix nanosleep task_struct leak |
| |
3.2-stable review patch. If anyone has any objections, please let me know.
------------------
From: Stanislaw Gruszka <sgruszka@redhat.com>
commit e6c42c295e071dd74a66b5a9fcf4f44049888ed8 upstream.
The trinity fuzzer triggered a task_struct reference leak via clock_nanosleep with CPU_TIMERs. do_cpu_nanosleep() calls posic_cpu_timer_create(), but misses a corresponding posix_cpu_timer_del() which leads to the task_struct reference leak.
Reported-and-tested-by: Tommi Rantala <tt.rantala@gmail.com> Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Dave Jones <davej@redhat.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Oleg Nesterov <oleg@redhat.com> Link: http://lkml.kernel.org/r/20130215100810.GF4392@redhat.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- kernel/posix-cpu-timers.c | 23 +++++++++++++++++++++-- 1 file changed, 21 insertions(+), 2 deletions(-)
--- a/kernel/posix-cpu-timers.c +++ b/kernel/posix-cpu-timers.c @@ -1450,8 +1450,10 @@ static int do_cpu_nanosleep(const clocki while (!signal_pending(current)) { if (timer.it.cpu.expires.sched == 0) { /* - * Our timer fired and was reset. + * Our timer fired and was reset, below + * deletion can not fail. */ + posix_cpu_timer_del(&timer); spin_unlock_irq(&timer.it_lock); return 0; } @@ -1469,9 +1471,26 @@ static int do_cpu_nanosleep(const clocki * We were interrupted by a signal. */ sample_to_timespec(which_clock, timer.it.cpu.expires, rqtp); - posix_cpu_timer_set(&timer, 0, &zero_it, it); + error = posix_cpu_timer_set(&timer, 0, &zero_it, it); + if (!error) { + /* + * Timer is now unarmed, deletion can not fail. + */ + posix_cpu_timer_del(&timer); + } spin_unlock_irq(&timer.it_lock); + while (error == TIMER_RETRY) { + /* + * We need to handle case when timer was or is in the + * middle of firing. In other cases we already freed + * resources. + */ + spin_lock_irq(&timer.it_lock); + error = posix_cpu_timer_del(&timer); + spin_unlock_irq(&timer.it_lock); + } + if ((it->it_value.tv_sec | it->it_value.tv_nsec) == 0) { /* * It actually did fire already.
|