[FFmpeg-devel] [PATCH 2/2] avformat/swfdec: Check outlen before allocation

[Anton Khirnov]

Quoting Michael Niedermayer (2021-01-22 15:09:47)
> Fixes: Timeout (too long -> 241ms)
> Fixes: 29083/clusterfuzz-testcase-minimized-ffmpeg_dem_SWF_fuzzer-6273684478230528
> 
> 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/swfdec.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/libavformat/swfdec.c b/libavformat/swfdec.c
> index 1463f0ad4d..aa4be88f91 100644
> --- a/libavformat/swfdec.c
> +++ b/libavformat/swfdec.c
> @@ -367,6 +367,9 @@ static int swf_read_packet(AVFormatContext *s, AVPacket *pkt)
>              ff_dlog(s, "bitmap: ch=%d fmt=%d %dx%d (linesize=%d) len=%d->%ld pal=%d\n",
>                      ch_id, bmp_fmt, width, height, linesize, len, out_len, colormapsize);
>  
> +            if (len * 17373LL < out_len)

Where does the magic number come from?

-- 
Anton Khirnov