linux-kernel - [PATCH] time: verify time values in adjtimex ADJ

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Date:	Thu,  3 Dec 2015 22:09:31 -0500
From:	Sasha Levin <sasha.levin@...cle.com>
To:	john.stultz@...aro.org, tglx@...utronix.de
Cc:	linux-kernel@...r.kernel.org, Sasha Levin <sasha.levin@...cle.com>
Subject: [PATCH] time: verify time values in adjtimex ADJ_SETOFFSET to avoid overflow

Make sure the tv_usec makes sense. We might multiply them later which can
cause an overflow and undefined behavior.

Signed-off-by: Sasha Levin <sasha.levin@...cle.com>
---
 kernel/time/timekeeping.c |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index d563c19..aa3c1c2 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1987,6 +1987,10 @@ int do_adjtimex(struct timex *txc)
 
 	if (txc->modes & ADJ_SETOFFSET) {
 		struct timespec delta;
+
+		if (txc->time.tv_usec >= USEC_PER_SEC || txc->time.tv_usec <= -USEC_PER_SEC)
+			return -EINVAL;
+
 		delta.tv_sec  = txc->time.tv_sec;
 		delta.tv_nsec = txc->time.tv_usec;
 		if (!(txc->modes & ADJ_NANO))
-- 
1.7.10.4

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