[FFmpeg-devel] [PATCH 2/3] avcodec/exr: Fix overflow with many blocks
Andreas Rheinhardt
andreas.rheinhardt at gmail.com
Sun Sep 27 11:21:25 EEST 2020
Michael Niedermayer:
> Fixes: signed integer overflow: 1073741827 * 8 cannot be represented in type 'int'
> Fixes: 25621/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_EXR_fuzzer-6304841641754624
>
> 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/exr.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/libavcodec/exr.c b/libavcodec/exr.c
> index c80e8eb5e0..8621a8cfe4 100644
> --- a/libavcodec/exr.c
> +++ b/libavcodec/exr.c
> @@ -1783,7 +1783,7 @@ static int decode_frame(AVCodecContext *avctx, void *data,
> if ((ret = ff_thread_get_buffer(avctx, &frame, 0)) < 0)
> return ret;
>
> - if (bytestream2_get_bytes_left(&s->gb) < nb_blocks * 8)
> + if (bytestream2_get_bytes_left(&s->gb) < nb_blocks * 8L)
Does this have an advantage over dividing by 8?
> return AVERROR_INVALIDDATA;
>
> // check offset table and recreate it if need
>
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