[FFmpeg-devel] [PATCH 4/5] avcodec/hevc_mp4toannexb_bsf: check that nalu size doesnt overflow

[Andriy Gelman]

On Fri, 13. Dec 01:28, Michael Niedermayer wrote:
> Fixes: Out of array access
> Fixes: 19299/clusterfuzz-testcase-minimized-ffmpeg_BSF_HEVC_MP4TOANNEXB_fuzzer-5169193398042624
> 
> 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/hevc_mp4toannexb_bsf.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/libavcodec/hevc_mp4toannexb_bsf.c b/libavcodec/hevc_mp4toannexb_bsf.c
> index d0f1b94f0e..baa93628ed 100644
> --- a/libavcodec/hevc_mp4toannexb_bsf.c
> +++ b/libavcodec/hevc_mp4toannexb_bsf.c
> @@ -152,8 +152,7 @@ static int hevc_mp4toannexb_filter(AVBSFContext *ctx, AVPacket *out)
>          extra_size    = add_extradata * ctx->par_out->extradata_size;
>          got_irap     |= is_irap;
>  
> -        if (SIZE_MAX - nalu_size < 4 ||
> -            SIZE_MAX - 4 - nalu_size < extra_size) {
> +        if (FFMIN(INT_MAX, SIZE_MAX) < 4ULL + nalu_size + extra_size) {
>              ret = AVERROR_INVALIDDATA;
>              goto fail;
>          }
> -- 
> 2.24.0

I already sent a patch for this:
http://ffmpeg.org/pipermail/ffmpeg-devel/2019-December/253972.html

-- 
Andriy