[FFmpeg-devel] [PATCH 4/8] avcodec/parser: clear padding in combine frame

[Kacper Michajlow]

On Sun, 4 Aug 2024 at 22:53, Michael Niedermayer <michael at niedermayer.cc> wrote:
>
> Fixes: use-of-uninitialized-value
> Fixes: 70852/clusterfuzz-testcase-minimized-ffmpeg_IO_DEMUXER_fuzzer-5179190066872320
>
> 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/parser.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/libavcodec/parser.c b/libavcodec/parser.c
> index af17ee9c156..426cc314fb0 100644
> --- a/libavcodec/parser.c
> +++ b/libavcodec/parser.c
> @@ -236,6 +236,7 @@ int ff_combine_frame(ParseContext *pc, int next,
>          }
>          pc->buffer = new_buffer;
>          memcpy(&pc->buffer[pc->index], *buf, *buf_size);
> +        memset(&pc->buffer[pc->index + *buf_size], 0, AV_INPUT_BUFFER_PADDING_SIZE);
>          pc->index += *buf_size;
>          return -1;
>      }
> --
> 2.45.2

We already had patch like that some time ago,
https://patchwork.ffmpeg.org/project/ffmpeg/patch/20240627004037.1336-2-kasper93@gmail.com/

- Kacper