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Message-ID: <5a70c141736e91f635f71d9922a3bbe993a76c69.camel@ndufresne.ca>
Date: Thu, 10 Aug 2023 09:58:17 -0400
From: Nicolas Dufresne <nicolas@...fresne.ca>
To: Wei Chen <harperchen1110@...il.com>, tiffany.lin@...iatek.com
Cc: andrew-ct.chen@...iatek.com, yunfei.dong@...iatek.com,
mchehab@...nel.org, matthias.bgg@...il.com,
angelogioacchino.delregno@...labora.com,
linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
linux-mediatek@...ts.infradead.org, stable@...r.kernel.org
Subject: Re: [PATCH v2] media: vcodec: Fix potential array out-of-bounds in
encoder queue_setup
Hi,
Le jeudi 10 août 2023 à 08:23 +0000, Wei Chen a écrit :
> 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.
>
> Fixes: 4e855a6efa54 ("[media] vcodec: mediatek: Add Mediatek V4L2 Video Encoder Driver")
> Signed-off-by: Wei Chen <harperchen1110@...il.com>
> Cc: stable@...r.kernel.org
> ---
> Changes in v2:
> - Add Fixes tag and CC stable email address
> - Change the title to be more expressive
>
> 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/drivers/media/platform/mediatek/vcodec/mtk_vcodec_enc.c
> index 9ff439a50f53..9e8817863cb8 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 != q_data->fmt->num_planes)
> + return -EINVAL;
I don't think the claim really exists. For this driver, when *nplane is set,
it will be:
case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
requested_planes = f->fmt.pix_mp.num_planes;
if (requested_planes == 0 ||
requested_planes > VIDEO_MAX_PLANES)
return -EINVAL;
for (i = 0; i < requested_planes; i++)
requested_sizes[i] =
f->fmt.pix_mp.plane_fmt[i].sizeimage;
break;
Or the value the driver have set it in the previous call with *nplane == 0. So
unless there is a bug, this should not happen, and more importantly, the core
should not let that happen, meaning it should not be driver jobs to validate
this.
my 2 cents,
Nicolas
> for (i = 0; i < *nplanes; i++)
> if (sizes[i] < q_data->sizeimage[i])
> return -EINVAL;
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