time: settimeofday: Validate the values of tv from user

commit 6ada1fc0e1c4775de0e043e1bd3ae9d065491aa5 upstream.

An unvalidated user input is multiplied by a constant, which can result in
an undefined behaviour for large values. While this is validated later,
we should avoid triggering undefined behaviour.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
[jstultz: include trivial milisecond->microsecond correction noticed
by Andy]
Signed-off-by: John Stultz <john.stultz@linaro.org>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/include/linux/time.h b/include/linux/time.h
index 8c0216e..a87b440 100644 (file)
--- a/include/linux/time.h
+++ b/include/linux/time.h
@@ -138,6 +138,19 @@ static inline bool timespec_valid_strict(const struct timespec *ts)
        return true;
 }
 
+static inline bool timeval_valid(const struct timeval *tv)
+{
+       /* Dates before 1970 are bogus */
+       if (tv->tv_sec < 0)
+               return false;
+
+       /* Can't have more microseconds then a second */
+       if (tv->tv_usec < 0 || tv->tv_usec >= USEC_PER_SEC)
+               return false;
+
+       return true;
+}
+
 extern void read_persistent_clock(struct timespec *ts);
 extern void read_boot_clock(struct timespec *ts);
 extern int update_persistent_clock(struct timespec now);

diff --cc kernel/time.c
Simple merge