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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Konstantin Khlebnikov <khlebnikov@yandex-team.ru>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@kernel.org>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 137/276] sched/rt: Check integer overflow at usec to nsec conversion
Date:   Wed, 29 May 2019 20:04:55 -0700
Message-Id: <20190530030534.285509068@linuxfoundation.org>
In-Reply-To: <20190530030523.133519668@linuxfoundation.org>
References: <20190530030523.133519668@linuxfoundation.org>
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[ Upstream commit 1a010e29cfa00fee2888fd2fd4983f848cbafb58 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/sched/rt.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 2e2955a8cf8fe..b980cc96604fa 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -2559,6 +2559,8 @@ 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);
 }
@@ -2579,6 +2581,9 @@ 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;
 
-- 
2.20.1