Commit 81f3affa authored by Laurent Pinchart's avatar Laurent Pinchart Committed by Mauro Carvalho Chehab
Browse files

media: uvcvideo: Don't expose unsupported formats to userspace 

When the uvcvideo driver encounters a format descriptor with an unknown
format GUID, it creates a corresponding struct uvc_format instance with
the fcc field set to 0. Since commit 50459f10 ("media: uvcvideo:
Remove format descriptions"), the driver relies on the V4L2 core to
provide the format description string, which the V4L2 core can't do
without a valid 4CC. This triggers a WARN_ON.

As a format with a zero 4CC can't be selected, it is unusable for
applications. Ignore the format completely without creating a uvc_format
instance, which fixes the warning.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=217252
Link: https://bugzilla.redhat.com/show_bug.cgi?id=2180107



Fixes: 50459f10 ("media: uvcvideo: Remove format descriptions")
Signed-off-by: default avatarLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: default avatarRicardo Ribalda <ribalda@chromium.org>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@kernel.org>
parent b37a356d

drivers/media/usb/uvc/uvc_driver.c

+11 −5
Original line number Diff line number Diff line
@@ -251,14 +251,17 @@ static int uvc_parse_format(struct uvc_device *dev, 
		/* Find the format descriptor from its GUID. */

		fmtdesc = uvc_format_by_guid(&buffer[5]);



		if (fmtdesc != NULL) {

			format->fcc = fmtdesc->fcc;

		} else {

		if (!fmtdesc) {

			/*

			 * Unknown video formats are not fatal errors, the

			 * caller will skip this descriptor.

			 */

			dev_info(&streaming->intf->dev,

				 "Unknown video format %pUl\n", &buffer[5]);

			format->fcc = 0;

			return 0;

		}



		format->fcc = fmtdesc->fcc;

		format->bpp = buffer[21];



		/*
@@ -675,7 +678,7 @@ static int uvc_parse_streaming(struct uvc_device *dev, 
	interval = (u32 *)&frame[nframes];



	streaming->format = format;

	streaming->nformats = nformats;

	streaming->nformats = 0;



	/* Parse the format descriptors. */

	while (buflen > 2 && buffer[1] == USB_DT_CS_INTERFACE) {
@@ -689,7 +692,10 @@ static int uvc_parse_streaming(struct uvc_device *dev, 
				&interval, buffer, buflen);

			if (ret < 0)

				goto error;

			if (!ret)

				break;



			streaming->nformats++;

			frame += format->nframes;

			format++;