[FFmpeg-devel] [PATCH 1/7] avformat/asfdec_o: shrink extradata to the initialized size

[James Almer]

On 4/23/2021 2:50 PM, Michael Niedermayer wrote:
> Fixes: OOM
> Fixes: 27240/clusterfuzz-testcase-minimized-ffmpeg_dem_ASF_O_fuzzer-5937469859823616
> 
> Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> ---
>   libavformat/asfdec_o.c | 6 +++++-
>   1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/libavformat/asfdec_o.c b/libavformat/asfdec_o.c
> index 6cfcd8b088..d08a09c14d 100644
> --- a/libavformat/asfdec_o.c
> +++ b/libavformat/asfdec_o.c
> @@ -600,8 +600,12 @@ static int parse_video_info(AVIOContext *pb, AVStream *st)
>           memset(st->codecpar->extradata + st->codecpar->extradata_size , 0,
>                  AV_INPUT_BUFFER_PADDING_SIZE);
>           if ((ret = avio_read(pb, st->codecpar->extradata,
> -                             st->codecpar->extradata_size)) < 0)
> +                             st->codecpar->extradata_size)) < 0) {
> +            st->codecpar->extradata_size = 0;
> +            av_freep(&st->codecpar->extradata);
>               return ret;
> +        }
> +        st->codecpar->extradata_size = ret;

Use ff_get_extradata() instead. It will simplify the code considerably 
and get the same result.

>       }
>       return 0;
>   }
>