[FFmpeg-devel] [PATCH 2/5] avcodec/smacker: Check input before allocation

[Andreas Rheinhardt]

Michael Niedermayer:
> Fixes: Timeout
> Fixes: 421650030/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_SMACKAUD_fuzzer-6144441767493632
> 
> 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/smacker.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/libavcodec/smacker.c b/libavcodec/smacker.c
> index bd08bc7be28..99009bfd361 100644
> --- a/libavcodec/smacker.c
> +++ b/libavcodec/smacker.c
> @@ -662,6 +662,10 @@ static int smka_decode_frame(AVCodecContext *avctx, AVFrame *frame,
>          } else
>              values[i] = h.entries[0].value;
>      }
> +    if (get_bits_left(&gb) < (stereo+1) * (bits+1) * 8) {
> +        ret = AVERROR_INVALIDDATA;
> +        goto error;
> +    }
>  
>      if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
>          return ret;

What about constant output (which you even optimized in
08e82e5b572b440f4faf160d2eac923ca47a59f8)?

- Andreas