From: Sean Young <sean@mess.org>
Date: Sun, 8 Oct 2017 18:18:52 +0000 (-0400)
Subject: media: rc: check for integer overflow
X-Git-Tag: v3.2.99~71
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cddb13de3968493647e4ae5c52311a596a93aa29;p=thirdparty%2Fkernel%2Fstable.git

media: rc: check for integer overflow

commit 3e45067f94bbd61dec0619b1c32744eb0de480c8 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>
[bwh: Backported to 3.2: open-code U32_MAX]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

diff --git a/drivers/media/rc/ir-lirc-codec.c b/drivers/media/rc/ir-lirc-codec.c
index 695fef9ce6b12..4ee9f4e5a71d5 100644
--- a/drivers/media/rc/ir-lirc-codec.c
+++ b/drivers/media/rc/ir-lirc-codec.c
@@ -255,11 +255,14 @@ static long ir_lirc_ioctl(struct file *filep, unsigned int cmd,
 		if (!dev->max_timeout)
 			return -ENOSYS;
 
+		/* Check for multiply overflow */
+		if (val > (u32)(-1) / 1000)
+			return -EINVAL;
+
 		tmp = val * 1000;
 
-		if (tmp < dev->min_timeout ||
-		    tmp > dev->max_timeout)
-				return -EINVAL;
+		if (tmp < dev->min_timeout || tmp > dev->max_timeout)
+			return -EINVAL;
 
 		dev->timeout = tmp;
 		break;