From: Alyssa Milburn <amilburn@zall.org>
Date: Sat, 1 Apr 2017 17:33:42 +0000 (-0300)
Subject: digitv: limit messages to buffer size
X-Git-Tag: v3.2.92~35
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=1a4b6a9aa3a892f819acf68d1a61765ec4dfc10d;p=thirdparty%2Fkernel%2Fstable.git

digitv: limit messages to buffer size

commit 821117dc21083a99dd99174c10848d70ff43de29 upstream.

Return an error rather than memcpy()ing beyond the end of the buffer.
Internal callers use appropriate sizes, but digitv_i2c_xfer may not.

Signed-off-by: Alyssa Milburn <amilburn@zall.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
[bwh: Backported to 3.2: adjust filename, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

diff --git a/drivers/media/dvb/dvb-usb/digitv.c b/drivers/media/dvb/dvb-usb/digitv.c
index f7184111aa645..67b2bd9ede0a4 100644
--- a/drivers/media/dvb/dvb-usb/digitv.c
+++ b/drivers/media/dvb/dvb-usb/digitv.c
@@ -30,6 +30,10 @@ static int digitv_ctrl_msg(struct dvb_usb_device *d,
 {
 	int wo = (rbuf == NULL || rlen == 0); /* write-only */
 	u8 sndbuf[7],rcvbuf[7];
+
+	if (wlen > 4 || rlen > 4)
+		return -EIO;
+
 	memset(sndbuf,0,7); memset(rcvbuf,0,7);
 
 	sndbuf[0] = cmd;