[PATCH 4.9 105/164] [media] digitv: limit messages to buffer size

From: Greg Kroah-Hartman
Date: Tue May 23 2017 - 17:35:53 EST


4.9-stable review patch. If anyone has any objections, please let me know.

------------------

From: Alyssa Milburn <amilburn@xxxxxxxx>

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@xxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/media/usb/dvb-usb/digitv.c | 3 +++
1 file changed, 3 insertions(+)

--- a/drivers/media/usb/dvb-usb/digitv.c
+++ b/drivers/media/usb/dvb-usb/digitv.c
@@ -33,6 +33,9 @@ static int digitv_ctrl_msg(struct dvb_us

wo = (rbuf == NULL || rlen == 0); /* write-only */

+ if (wlen > 4 || rlen > 4)
+ return -EIO;
+
memset(st->sndbuf, 0, 7);
memset(st->rcvbuf, 0, 7);