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References: <20230328092608.523933-1-harperchen1110@gmail.com>
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From:   Tomasz Figa <tfiga@chromium.org>
Date:   Thu, 15 Jun 2023 01:23:52 +0900
Message-ID: <CAAFQd5CqhZgtCJ_-6M0=dYAfVs0TFeBjPURvosS_24qgour=Ow@mail.gmail.com>
Subject: Re: [PATCH] media: vcodec: Fix potential array out-of-bounds in vb2ops_venc_queue_setup
To:     Wei Chen <harperchen1110@gmail.com>
Cc:     tiffany.lin@mediatek.com, andrew-ct.chen@mediatek.com,
        yunfei.dong@mediatek.com, mchehab@kernel.org,
        matthias.bgg@gmail.com, angelogioacchino.delregno@collabora.com,
        linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org
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On Tue, Mar 28, 2023 at 6:26=E2=80=AFPM Wei Chen <harperchen1110@gmail.com>=
 wrote:
>
> variable *nplanes is provided by user via system call argument. The
> possible value of q_data->fmt->num_planes is 1-3, while the value
> of *nplanes can be 1-8. The array access by index i can cause array
> out-of-bounds.
>
> Fix this bug by checking *nplanes against the array size.
>
> Signed-off-by: Wei Chen <harperchen1110@gmail.com>
> ---
>  drivers/media/platform/mediatek/vcodec/mtk_vcodec_enc.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/drivers/media/platform/mediatek/vcodec/mtk_vcodec_enc.c b/dr=
ivers/media/platform/mediatek/vcodec/mtk_vcodec_enc.c
> index d65800a3b89d..1ea02f9136f6 100644
> --- a/drivers/media/platform/mediatek/vcodec/mtk_vcodec_enc.c
> +++ b/drivers/media/platform/mediatek/vcodec/mtk_vcodec_enc.c
> @@ -821,6 +821,8 @@ static int vb2ops_venc_queue_setup(struct vb2_queue *=
vq,
>                 return -EINVAL;
>
>         if (*nplanes) {
> +               if (*nplanes !=3D q_data->fmt->num_planes)
> +                       return -EINVAL;
>                 for (i =3D 0; i < *nplanes; i++)
>                         if (sizes[i] < q_data->sizeimage[i])
>                                 return -EINVAL;
> --
> 2.25.1
>

Thanks for the patch, it makes sense indeed.

Reviewed-by: Tomasz Figa <tfiga@chromium.org>

Best regards,
Tomasz