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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/media/usb/dvb-usb/digitv.c b/drivers/media/usb/dvb-usb/digitv.c
index 4284f69..475a3c0 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);