[FFmpeg-devel] [PATCH 4/9] avformat/wtvdec: Improve size overflow checks in parse_chunks()

[Peter Ross]

On Mon, Apr 19, 2021 at 08:23:41PM +0200, Michael Niedermayer wrote:
> Fixes: signed integer overflow: 32 + 2147483647 cannot be represented in type 'int
> Fixes: 32967/clusterfuzz-testcase-minimized-ffmpeg_dem_WTV_fuzzer-5132856218222592
> 
> 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/wtvdec.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/libavformat/wtvdec.c b/libavformat/wtvdec.c
> index 44ca86d517..2f1b192cea 100644
> --- a/libavformat/wtvdec.c
> +++ b/libavformat/wtvdec.c
> @@ -809,7 +809,7 @@ static int parse_chunks(AVFormatContext *s, int mode, int64_t seekts, int *len_p
>                  avio_skip(pb, 12);
>                  ff_get_guid(pb, &formattype);
>                  size = avio_rl32(pb);
> -                if (size < 0 || size > INT_MAX - 92)
> +                if (size < 0 || size > INT_MAX - 92 - consumed)
>                      return AVERROR_INVALIDDATA;
>                  parse_media_type(s, 0, sid, mediatype, subtype, formattype, size);
>                  consumed += 92 + size;
> @@ -825,7 +825,7 @@ static int parse_chunks(AVFormatContext *s, int mode, int64_t seekts, int *len_p
>                  avio_skip(pb, 12);
>                  ff_get_guid(pb, &formattype);
>                  size = avio_rl32(pb);
> -                if (size < 0 || size > INT_MAX - 76)
> +                if (size < 0 || size > INT_MAX - 76 - consumed)
>                      return AVERROR_INVALIDDATA;
>                  parse_media_type(s, s->streams[stream_index], sid, mediatype, subtype, formattype, size);
>                  consumed += 76 + size;
> -- 

please apply

-- Peter
(A907 E02F A6E5 0CD2 34CD 20D2 6760 79C5 AC40 DD6B)
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