media: rc: check for integer overflow

BugLink: http://bugs.launchpad.net/bugs/1744873

commit 3e45067f upstream.

The ioctl LIRC_SET_REC_TIMEOUT would set a timeout of 704ns if called
with a timeout of 4294968us.
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

drivers/media/rc/ir-lirc-codec.c

@@ -286,10 +286,13 @@ static long ir_lirc_ioctl(struct file *filep, unsigned int cmd,
 		if (!dev->max_timeout)
 			return -ENOSYS;
 
+		/* Check for multiply overflow */
+		if (val > U32_MAX / 1000)
+			return -EINVAL;
+
 		tmp = val * 1000;
 
-		if (tmp < dev->min_timeout ||
-		    tmp > dev->max_timeout)
+		if (tmp < dev->min_timeout || tmp > dev->max_timeout)
 			return -EINVAL;
 
 		dev->timeout = tmp;