[PATCH 1/7] time: make sure tz_minuteswest is set to a valid value when setting time

John Stultz
2015-05-20T17:19:53Z

From: Sasha Levin <sasha.levin@oracle.com>

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>
---
kernel/time/time.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/kernel/time/time.c b/kernel/time/time.c
index c42c2c3..972e3bb 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) {
--
1.9.1