[FFmpeg-devel] [PATCH 1/2] avcodec/cbs_vp9: Check index_size

[James Almer]

On 12/14/2019 9:08 AM, Michael Niedermayer wrote:
> Fixes: out of array read
> Fixes: 19300/clusterfuzz-testcase-minimized-ffmpeg_BSF_VP9_METADATA_fuzzer-5653911730126848
> 
> 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_vp9.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/libavcodec/cbs_vp9.c b/libavcodec/cbs_vp9.c
> index 42e4dcf5ac..98730e03e3 100644
> --- a/libavcodec/cbs_vp9.c
> +++ b/libavcodec/cbs_vp9.c
> @@ -428,6 +428,9 @@ static int cbs_vp9_split_fragment(CodedBitstreamContext *ctx,
>          index_size = 2 + (((superframe_header & 0x18) >> 3) + 1) *
>                            ((superframe_header & 0x07) + 1);
>  
> +        if (index_size > frag->data_size)
> +            return AVERROR_INVALIDDATA;
> +
>          err = init_get_bits(&gbc, frag->data + frag->data_size - index_size,
>                              8 * index_size);
>          if (err < 0)

Should be ok.