[FFmpeg-devel] [PATCH 1/3] avcodec/vp3: Do not initialize unused tables for keyframes in unpack_superblock()

[James Almer]

On 10/28/2018 11:04 AM, Michael Niedermayer wrote:
> Fixes: Timeout (139sec -> 102sec)
> Fixes: 9642/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_VP3_fuzzer-6676767875006464
> 
> 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/vp3.c | 16 +++++++++++++++-
>  1 file changed, 15 insertions(+), 1 deletion(-)
> 
> diff --git a/libavcodec/vp3.c b/libavcodec/vp3.c
> index 0e6da89abb..348416b25d 100644
> --- a/libavcodec/vp3.c
> +++ b/libavcodec/vp3.c
> @@ -544,8 +544,21 @@ static int unpack_superblocks(Vp3DecodeContext *s, GetBitContext *gb)
>                                           : s->y_superblock_count);
>          int num_coded_frags = 0;
>  
> +        if (s->keyframe) {
> +            for (i = sb_start; i < sb_end; i++) {
> +                /* iterate through all 16 fragments in a superblock */
> +                for (j = 0; j < 16; j++) {
> +                    /* if the fragment is in bounds, check its coding status */
> +                    current_fragment = s->superblock_fragments[i * 16 + j];
> +                    if (current_fragment != -1) {
> +                        s->coded_fragment_list[plane][num_coded_frags++] =
> +                            current_fragment;
> +                    }
> +                }
> +            }
> +        } else {
>          for (i = sb_start; i < sb_end && get_bits_left(gb) > 0; i++) {
> -            if (s->keyframe == 0 && get_bits_left(gb) < plane0_num_coded_frags >> 2) {
> +            if (get_bits_left(gb) < plane0_num_coded_frags >> 2) {
>                  return AVERROR_INVALIDDATA;
>              }
>              /* iterate through all 16 fragments in a superblock */
> @@ -580,6 +593,7 @@ static int unpack_superblocks(Vp3DecodeContext *s, GetBitContext *gb)
>                  }
>              }
>          }
> +        }
>          if (!plane)
>              plane0_num_coded_frags = num_coded_frags;
>          s->total_num_coded_frags += num_coded_frags;

Please reindent before you push, either as a separate commit or directly
in this one.