[FFmpeg-devel] [PATCH 1/2] avcodec/cinepak: Check slice_size before allocating image

[Tomas Härdin]

sön 2019-04-28 klockan 11:42 +0200 skrev Michael Niedermayer:
> Fixes: Timeout (16sec -> 125msec)
> Fixes: 14283/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_CINEPAK_fuzzer-5742851457024000
> 
> 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/cinepak.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/libavcodec/cinepak.c b/libavcodec/cinepak.c
> index 9b0077402f..d26c505222 100644
> --- a/libavcodec/cinepak.c
> +++ b/libavcodec/cinepak.c
> @@ -353,6 +353,13 @@ static int cinepak_predecode_check (CinepakContext *s)
>      if (s->size < 10 + s->sega_film_skip_bytes + num_strips * 12)
>          return AVERROR_INVALIDDATA;
>  
> +    if (num_strips) {
> +        uint8_t *data = s->data + 10 + s->sega_film_skip_bytes;
> +        int strip_size = AV_RB24 (data + 1);

Should be OK since the check just before this ensures data[0..11] are
valid

/Tomas