time: settimeofday: Validate the values of tv from user

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>
Cc: stable <stable@vger.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>

1 files changed, 4 insertions, 0 deletions

diff --git a/kernel/time/time.c b/kernel/time/time.c
index a9ae20fb0b11..22d5d3b73970 100644
--- a/kernel/time/time.c
+++ b/kernel/time/time.c
@@ -196,6 +196,10 @@ SYSCALL_DEFINE2(settimeofday, struct timeval __user *, tv,
         if (tv) {
                 if (copy_from_user(&user_tv, tv, sizeof(*tv)))
                         return -EFAULT;
+
+                if (!timeval_valid(&user_tv))
+                        return -EINVAL;
+
                 new_ts.tv_sec = user_tv.tv_sec;
                 new_ts.tv_nsec = user_tv.tv_usec * NSEC_PER_USEC;
         }