[FFmpeg-devel] [PATCH 1/3] avcodec/cbs_h265_syntax_template: Check inter_ref_pic_set_prediction_flag

[James Almer]

On 6/6/2020 1:03 PM, Michael Niedermayer wrote:
> Fixes: out of array access
> Fixes: 23034/clusterfuzz-testcase-minimized-ffmpeg_BSF_HEVC_METADATA_fuzzer-5074645169733632.fuzz
> 
> Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> ---
>  libavcodec/cbs_h265_syntax_template.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/libavcodec/cbs_h265_syntax_template.c b/libavcodec/cbs_h265_syntax_template.c
> index 5b7d1aa837..900764a3cf 100644
> --- a/libavcodec/cbs_h265_syntax_template.c
> +++ b/libavcodec/cbs_h265_syntax_template.c
> @@ -518,8 +518,11 @@ static int FUNC(st_ref_pic_set)(CodedBitstreamContext *ctx, RWContext *rw,
>  
>      if (st_rps_idx != 0)
>          flag(inter_ref_pic_set_prediction_flag);
> -    else
> +    else {
>          infer(inter_ref_pic_set_prediction_flag, 0);
> +        if (current->inter_ref_pic_set_prediction_flag)

This makes no sense. The infer(inter_ref_pic_set_prediction_flag, 0)
line sets current->inter_ref_pic_set_prediction_flag to 0. How can this
check even succeed?

Can you give some context?

> +            return AVERROR_INVALIDDATA;
> +    }
>  
>      if (current->inter_ref_pic_set_prediction_flag) {
>          unsigned int ref_rps_idx, num_delta_pocs, num_ref_pics;
>