[FFmpeg-devel] [PATCH] avcodec/vp6: Check alpha_context for allocation failures

[Andreas Rheinhardt]

Steven Liu:
> Fixes: null pointer dereference
> 
> Reported-by: TOTE Robot <oslab at tsinghua.edu.cn>
> Signed-off-by: Steven Liu <lq at chinaffmpeg.org>
> ---
>  libavcodec/vp6.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/libavcodec/vp6.c b/libavcodec/vp6.c
> index d024370793..7ddabbff80 100644
> --- a/libavcodec/vp6.c
> +++ b/libavcodec/vp6.c
> @@ -653,6 +653,8 @@ static av_cold int vp6_decode_init(AVCodecContext *avctx)
>  
>      if (s->has_alpha) {
>          s->alpha_context = av_mallocz(sizeof(VP56Context));
> +        if (!s->alpha_context)
> +            return AVERROR(ENOMEM);
>          ff_vp56_init_context(avctx, s->alpha_context,
>                               s->flip == -1, s->has_alpha);
>          ff_vp6dsp_init(&s->alpha_context->vp56dsp);

Already fixed by
https://ffmpeg.org/pipermail/ffmpeg-devel/2022-February/292714.html
(pushed as c4d63dbc9417ddf77f6e33f6144b23da7e97cb3b). Furthermore, your
patch would leak in case of allocation failure.

- Andreas