media: uvcvideo: Skip parsing frames of type UVC_VS_UNDEFINED in uvc_…

…parse_format

This can lead to out of bounds writes since frames of this type were not
taken into account when calculating the size of the frames buffer in
uvc_parse_streaming.

Fixes: c0efd23 ("V4L/DVB (8145a): USB Video Class driver")
Signed-off-by: Benoit Sevens <bsevens@google.com>
Cc: stable@vger.kernel.org
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>

drivers/media/usb/uvc/uvc_driver.c

@@ -371,7 +371,7 @@ static int uvc_parse_format(struct uvc_device *dev,
 	 * Parse the frame descriptors. Only uncompressed, MJPEG and frame
 	 * based formats have frame descriptors.
 	 */
-	while (buflen > 2 && buffer[1] == USB_DT_CS_INTERFACE &&
+	while (ftype && buflen > 2 && buffer[1] == USB_DT_CS_INTERFACE &&
 	       buffer[2] == ftype) {
 		unsigned int maxIntervalIndex;