Commit 1a010e29 authored Feb 27, 2019 by Konstantin Khlebnikov Committed by Ingo Molnar Apr 19, 2019

sched/rt: Check integer overflow at usec to nsec conversion



Example of unhandled overflows:

 # echo 18446744073709651 > cpu.rt_runtime_us
 # cat cpu.rt_runtime_us
 99

 # echo 18446744073709900 > cpu.rt_period_us
 # cat cpu.rt_period_us
 348

After this patch they will fail with -EINVAL.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/155125501739.293431.5252197504404771496.stgit@buzz


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent bee98539

kernel/sched/rt.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -2555,6 +2555,8 @@ int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us)
		rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC;
		if (rt_runtime_us < 0)
		rt_runtime = RUNTIME_INF;
		else if ((u64)rt_runtime_us > U64_MAX / NSEC_PER_USEC)
		return -EINVAL;

		return tg_set_rt_bandwidth(tg, rt_period, rt_runtime);
		}
		@@ -2575,6 +2577,9 @@ int sched_group_set_rt_period(struct task_group *tg, u64 rt_period_us)
		{
		u64 rt_runtime, rt_period;

		if (rt_period_us > U64_MAX / NSEC_PER_USEC)
		return -EINVAL;

		rt_period = rt_period_us * NSEC_PER_USEC;
		rt_runtime = tg->rt_bandwidth.rt_runtime;

Admin message