media: uvcvideo: Skip parsing frames of type UVC_VS_UNDEFINED in uvc_parse_format

commit ecf2b43 upstream.

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

Author: dlelcldkekslele

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;