Re: [PATCH v5 1/4] media: uvcvideo: Do not mark valid metadata as invalid

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Ricardo,

Thank you for the patch.

On Fri, Apr 04, 2025 at 06:37:34AM +0000, Ricardo Ribalda wrote:
> Currently, the driver performs a length check of the metadata buffer
> before the actual metadata size is known and before the metadata is
> decided to be copied. This results in valid metadata buffers being
> incorrectly marked as invalid.
> 
> Move the length check to occur after the metadata size is determined and
> is decided to be copied.
> 
> Cc: stable@vger.kernel.org
> Fixes: 088ead255245 ("media: uvcvideo: Add a metadata device node")
> Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> ---
>  drivers/media/usb/uvc/uvc_video.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
> index e3567aeb0007c1f0a766f331e4e744359e95a863..b113297dac61f1b2eecd72c36ea61ef2c1e7d28a 100644
> --- a/drivers/media/usb/uvc/uvc_video.c
> +++ b/drivers/media/usb/uvc/uvc_video.c
> @@ -1433,12 +1433,6 @@ static void uvc_video_decode_meta(struct uvc_streaming *stream,
>  	if (!meta_buf || length == 2)
>  		return;
>  
> -	if (meta_buf->length - meta_buf->bytesused <
> -	    length + sizeof(meta->ns) + sizeof(meta->sof)) {
> -		meta_buf->error = 1;
> -		return;
> -	}
> -
>  	has_pts = mem[1] & UVC_STREAM_PTS;
>  	has_scr = mem[1] & UVC_STREAM_SCR;
>  
> @@ -1459,6 +1453,12 @@ static void uvc_video_decode_meta(struct uvc_streaming *stream,
>  				  !memcmp(scr, stream->clock.last_scr, 6)))
>  		return;
>  
> +	if (meta_buf->length - meta_buf->bytesused <
> +	    length + sizeof(meta->ns) + sizeof(meta->sof)) {
> +		meta_buf->error = 1;
> +		return;
> +	}
> +
>  	meta = (struct uvc_meta_buf *)((u8 *)meta_buf->mem + meta_buf->bytesused);
>  	local_irq_save(flags);
>  	time = uvc_video_get_time();

-- 
Regards,

Laurent Pinchart