Re: [FFmpeg-devel] [PATCH v2 1/2] avcodec/vvc_mp4toannexb: check bytes left for nalu_len

[Andreas Rheinhardt <andreas.rheinhardt@outlook.com>]

Nuo Mi:
> Fixes: fuzzer timeout
> Fixes: 65253/clusterfuzz-testcase-minimized-ffmpeg_BSF_VVC_MP4TOANNEXB_fuzzer-4972412487467008
> 
> Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
> ---
>  libavcodec/bsf/vvc_mp4toannexb.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/libavcodec/bsf/vvc_mp4toannexb.c b/libavcodec/bsf/vvc_mp4toannexb.c
> index 25c3726918..36bdae8f49 100644
> --- a/libavcodec/bsf/vvc_mp4toannexb.c
> +++ b/libavcodec/bsf/vvc_mp4toannexb.c
> @@ -155,10 +155,11 @@ static int vvc_extradata_to_annexb(AVBSFContext *ctx)
>          }
>  
>          for (j = 0; j < cnt; j++) {
> -            int nalu_len = bytestream2_get_be16(&gb);
> +            const int nalu_len = bytestream2_get_be16(&gb);
>  
> -            if (4 + AV_INPUT_BUFFER_PADDING_SIZE + nalu_len >
> -                SIZE_MAX - new_extradata_size) {
> +            if (!nalu_len ||
> +                nalu_len > bytestream2_get_bytes_left(&gb) ||
> +                4 + AV_INPUT_BUFFER_PADDING_SIZE + nalu_len > SIZE_MAX - new_extradata_size) {
>                  ret = AVERROR_INVALIDDATA;
>                  goto fail;
>              }

What about growing the packet?

- Andreas

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