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Date:   Tue, 27 Jun 2023 16:06:40 +0200
From:   Alain Volmat <alain.volmat@foss.st.com>
To:     <yqsun1997@gmail.com>
CC:     <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>, <499671216@qq.com>
Subject: Re: [PATCH] OOB read and write in mdp_prepare_buffer
Message-ID: <20230627140640.GA3605278@gnbcxd0016.gnb.st.com>
Mail-Followup-To: yqsun1997@gmail.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,
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References: <20230627082731.1769620-1-yqsun1997@gmail.com>
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In-Reply-To: <20230627082731.1769620-1-yqsun1997@gmail.com>
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Hi,

On Tue, Jun 27, 2023 at 04:27:31PM +0800, yqsun1997@gmail.com wrote:
> From: yqsun1997 <yqsun1997@gmail.com>
> 
> Because format in struct img_image_buffer max index is IMG_MAX_PLANES ==3,
> The num_planes max index is 8.so will be OOB like in mdp_prepare_buffer.

Similarly as your other patch, could you describe why you need to
increase the IMG_MAX_PLANES while I suspect your driver only needs to
deal with 3 planes.  While the maximum num_planes value that can be
given by the user is 8, this has to be first compared to the configured
format prior to reaching this function.

> 
> static void mdp_prepare_buffer(struct img_image_buffer *b,
>                                struct mdp_frame *frame, struct vb2_buffer *vb)
> {
>         struct v4l2_pix_format_mplane *pix_mp = &frame->format.fmt.pix_mp;
>         unsigned int i;
> 
>         b->format.colorformat = frame->mdp_fmt->mdp_color;
>         b->format.ycbcr_prof = frame->ycbcr_prof;
>         for (i = 0; i < pix_mp->num_planes; ++i) {
>                 u32 stride = mdp_fmt_get_stride(frame->mdp_fmt,
>                         pix_mp->plane_fmt[i].bytesperline, i);
> 
>                 b->format.plane_fmt[i].stride = stride;  //oob
>                 ......
> 
> Signed-off-by: yqsun1997 <yqsun1997@gmail.com>
> ---
>  drivers/media/platform/mediatek/mdp3/mtk-mdp3-type.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/media/platform/mediatek/mdp3/mtk-mdp3-type.h b/drivers/media/platform/mediatek/mdp3/mtk-mdp3-type.h
> index ae0396806..e2e991a34 100644
> --- a/drivers/media/platform/mediatek/mdp3/mtk-mdp3-type.h
> +++ b/drivers/media/platform/mediatek/mdp3/mtk-mdp3-type.h
> @@ -11,7 +11,7 @@
>  
>  #define IMG_MAX_HW_INPUTS	3
>  #define IMG_MAX_HW_OUTPUTS	4
> -#define IMG_MAX_PLANES		3
> +#define IMG_MAX_PLANES		8
>  #define IMG_MAX_COMPONENTS	20
>  
>  struct img_crop {
> -- 
> 2.39.2
> 

Regards,
Alain