From 526fbce5b0e44c67a97c57656b3be9911f0a9b9b Mon Sep 17 00:00:00 2001
From: Laura Abbott <labbott@fedoraproject.org>
Date: Tue, 29 Sep 2015 16:59:20 -0700
Subject: [PATCH 2/2] si2157: Bounds check firmware
To: Antti Palosaari <crope@iki.fi>
To: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Cc: Olli Salonen <olli.salonen@iki.fi>
Cc: linux-media@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

When reading the firmware and sending commands, the length
must be bounds checked to avoid overrunning the size of the command
buffer and smashing the stack if the firmware is not in the
expected format. Add the proper check.

Cc: stable@kernel.org
Signed-off-by: Laura Abbott <labbott@fedoraproject.org>
---
 drivers/media/tuners/si2157.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/media/tuners/si2157.c b/drivers/media/tuners/si2157.c
index 5073821..ce157ed 100644
--- a/drivers/media/tuners/si2157.c
+++ b/drivers/media/tuners/si2157.c
@@ -166,6 +166,10 @@ static int si2157_init(struct dvb_frontend *fe)
 
 	for (remaining = fw->size; remaining > 0; remaining -= 17) {
 		len = fw->data[fw->size - remaining];
+		if (len > SI2157_ARGLEN) {
+			dev_err(&client->dev, "Bad firmware length\n");
+			goto err_release_firmware;
+		}
 		memcpy(cmd.args, &fw->data[(fw->size - remaining) + 1], len);
 		cmd.wlen = len;
 		cmd.rlen = 1;
-- 
2.4.3