[media] digitv: limit messages to buffer size

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>
Cc: stable@vger.kernel.org
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

diff --git a/drivers/media/usb/dvb-usb/digitv.c b/drivers/media/usb/dvb-usb/digitv.c
index 4284f6984dc1ffe14698b6fcdc42aad8cf69bf32..475a3c0cdee7f88a9630f337cd9d0aaf59f2e177 100644 (file)
--- 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_usb_device *d,
 
        wo = (rbuf == NULL || rlen == 0); /* write-only */
 
+       if (wlen > 4 || rlen > 4)
+               return -EIO;
+
        memset(st->sndbuf, 0, 7);
        memset(st->rcvbuf, 0, 7);