uvcvideo: Fix uvc_fixup_video_ctrl() format search

commit 38a66824 upstream.

The scheme used to index format in uvc_fixup_video_ctrl() is not robust:
format index is based on descriptor ordering, which does not necessarily
match bFormatIndex ordering.  Searching for first matching format will
prevent uvc_fixup_video_ctrl() from using the wrong format/frame to make
adjustments.
Signed-off-by: Stephan Lachowsky <stephan.lachowsky@maxim-ic.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/media/video/uvc/uvc_video.c

@@ -64,15 +64,19 @@ int uvc_query_ctrl(struct uvc_device *dev, __u8 query, __u8 unit,
 static void uvc_fixup_video_ctrl(struct uvc_streaming *stream,
 	struct uvc_streaming_control *ctrl)
 {
-	struct uvc_format *format;
+	struct uvc_format *format = NULL;
 	struct uvc_frame *frame = NULL;
 	unsigned int i;
 
-	if (ctrl->bFormatIndex <= 0 ||
-	    ctrl->bFormatIndex > stream->nformats)
-		return;
+	for (i = 0; i < stream->nformats; ++i) {
+		if (stream->format[i].index == ctrl->bFormatIndex) {
+			format = &stream->format[i];
+			break;
+		}
+	}
 
-	format = &stream->format[ctrl->bFormatIndex - 1];
+	if (format == NULL)
+		return;
 
 	for (i = 0; i < format->nframes; ++i) {
 		if (format->frame[i].bFrameIndex == ctrl->bFrameIndex) {