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References: <20220325022337.10893-1-hbh25y@gmail.com>
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From:   Ricardo Ribalda <ribalda@chromium.org>
Date:   Fri, 25 Mar 2022 16:37:21 +0100
Message-ID: <CANiDSCuprLdo0i2VE3Vhe=t9cSYwW_Czvyyps=nOqLmrWn_uJA@mail.gmail.com>
Subject: Re: [PATCH v2] media: uvc_video: fix bit overflow in uvc_probe_video
To:     Hangyu Hua <hbh25y@gmail.com>
Cc:     laurent.pinchart@ideasonboard.com, mchehab@kernel.org,
        linux-media@vger.kernel.org, linux-kernel@vger.kernel.org
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On Fri, 25 Mar 2022 at 16:34, Hangyu Hua <hbh25y@gmail.com> wrote:
>
> probe->dwMaxPayloadTransferSize is a 32bit value, but bandwidth is 16bit. This
> may lead to a bit overflow.
>
> Fix this by using probe->dwMaxPayloadTransferSize directly.
>
> Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
Reviewed-by: Ricardo Ribalda <ribalda@chromium.org>
> ---
>
> v2:
> Use probe->dwMaxPayloadTransferSize directly instead of changing temporary
> variable.
>
>  drivers/media/usb/uvc/uvc_video.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
> index 1b4cc934109e..e016f88bdf96 100644
> --- a/drivers/media/usb/uvc/uvc_video.c
> +++ b/drivers/media/usb/uvc/uvc_video.c
> @@ -383,7 +383,6 @@ int uvc_probe_video(struct uvc_streaming *stream,
>         struct uvc_streaming_control *probe)
>  {
>         struct uvc_streaming_control probe_min, probe_max;
> -       u16 bandwidth;
>         unsigned int i;
>         int ret;
>
> @@ -421,8 +420,7 @@ int uvc_probe_video(struct uvc_streaming *stream,
>                 if (stream->intf->num_altsetting == 1)
>                         break;
>
> -               bandwidth = probe->dwMaxPayloadTransferSize;
> -               if (bandwidth <= stream->maxpsize)
> +               if (probe->dwMaxPayloadTransferSize <= stream->maxpsize)
>                         break;
>
>                 if (stream->dev->quirks & UVC_QUIRK_PROBE_MINMAX) {
> --
> 2.25.1
>


-- 
Ricardo Ribalda