[FFmpeg-devel] [PATCH 1/3] avcodec/vp8: Move end check into MB loop in vp78_decode_mv_mb_modes()

[Peter Ross]

On Mon, Feb 15, 2021 at 09:23:11PM +0100, Michael Niedermayer wrote:
> Fixes: Timeout (long -> 5sec)
> Fixes: 30269/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_VP7_fuzzer-5430325004075008
> 
> 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/vp8.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/libavcodec/vp8.c b/libavcodec/vp8.c
> index 5fa7971f8f..89c48e6cb1 100644
> --- a/libavcodec/vp8.c
> +++ b/libavcodec/vp8.c
> @@ -2293,10 +2293,10 @@ int vp78_decode_mv_mb_modes(AVCodecContext *avctx, VP8Frame *curframe,
>          s->mv_bounds.mv_min.x = -MARGIN;
>          s->mv_bounds.mv_max.x = ((s->mb_width - 1) << 6) + MARGIN;
>  
> -        if (vpX_rac_is_end(&s->c)) {
> -            return AVERROR_INVALIDDATA;
> -        }
>          for (mb_x = 0; mb_x < s->mb_width; mb_x++, mb_xy++, mb++) {
> +            if (vpX_rac_is_end(&s->c)) {
> +                return AVERROR_INVALIDDATA;
> +            }
>              if (mb_y == 0)
>                  AV_WN32A((mb - s->mb_width - 1)->intra4x4_pred_mode_top,
>                           DC_PRED * 0x01010101);

ok

-- Peter
(A907 E02F A6E5 0CD2 34CD 20D2 6760 79C5 AC40 DD6B)
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