From: Sasha Levin <sasha.levin@oracle.com>
Date: Tue, 2 Dec 2014 04:04:06 +0000 (-0500)
Subject: time: Make sure tz_minuteswest is set to a valid value when setting time
X-Git-Tag: v4.2-rc1~165^2~38
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=6f7d79849a00bba82d3139ff91ff2aaabd12841e;p=karo-tx-linux.git

time: Make sure tz_minuteswest is set to a valid value when setting time

Invalid values may overflow later, leading to undefined behaviour when
multiplied by 60 to get the amount of seconds.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---

diff --git a/kernel/time/time.c b/kernel/time/time.c
index c42c2c3214fe..972e3bbac963 100644
--- a/kernel/time/time.c
+++ b/kernel/time/time.c
@@ -173,6 +173,10 @@ int do_sys_settimeofday(const struct timespec *tv, const struct timezone *tz)
 		return error;
 
 	if (tz) {
+		/* Verify we're witin the +-15 hrs range */
+		if (tz->tz_minuteswest > 15*60 || tz->tz_minuteswest < -15*60)
+			return -EINVAL;
+
 		sys_tz = *tz;
 		update_vsyscall_tz();
 		if (firsttime) {