[PATCH] [233/275] uvcvideo: Fix uvc_fixup_video_ctrl() format search

[Andi Kleen]

2.6.35-longterm review patch.  If anyone has any objections, please let me know.

------------------
From: Stephan Lachowsky <stephan.lachowsky@xxxxxxxxxxxx>

commit 38a66824d96de8aeeb915e6f46f0d3fe55828eb1 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@xxxxxxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>

---
 drivers/media/video/uvc/uvc_video.c |   14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

Index: linux-2.6.35.y/drivers/media/video/uvc/uvc_video.c
===================================================================
--- linux-2.6.35.y.orig/drivers/media/video/uvc/uvc_video.c	2011-03-29 22:50:21.561706709 -0700
+++ linux-2.6.35.y/drivers/media/video/uvc/uvc_video.c	2011-03-29 23:03:03.081221330 -0700
@@ -65,15 +65,19 @@
 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) {
--
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