[FFmpeg-devel] [PATCH 1/2] avcodec/notchlc: Check uncompressed size against input for LZ4

[Paul B Mahol]

On Wed, Oct 14, 2020 at 05:53:07PM +0200, Michael Niedermayer wrote:
> Fixes: OOM
> Fixes: 26168/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_NOTCHLC_fuzzer-6019839015256064
> 
> 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/notchlc.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/libavcodec/notchlc.c b/libavcodec/notchlc.c
> index 3f7079da70..0254e7d76a 100644
> --- a/libavcodec/notchlc.c
> +++ b/libavcodec/notchlc.c
> @@ -490,6 +490,9 @@ static int decode_frame(AVCodecContext *avctx,
>  
>          bytestream2_init(gb, s->lzf_buffer, uncompressed_size);
>      } else if (s->format == 1) {
> +        if (bytestream2_get_bytes_left(gb) < uncompressed_size / 255)

>From where you picked this division? And expecially 255 number?

> +            return AVERROR_INVALIDDATA;
> +
>          av_fast_padded_malloc(&s->uncompressed_buffer, &s->uncompressed_size,
>                                uncompressed_size);
>          if (!s->uncompressed_buffer)
> -- 
> 2.17.1
> 
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