[FFmpeg-devel] [PATCH] avcodec/agm: Fix integer overflow with w/h

[Paul B Mahol]

On 4/5/19, Michael Niedermayer <michael at niedermayer.cc> wrote:
> Fixes: negation of -2147483648 cannot be represented in type 'int'; cast to
> an unsigned type to negate this value to itself
> Fixes:
> 13999/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_AGM_fuzzer-5644405991538688
>
> 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/agm.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/libavcodec/agm.c b/libavcodec/agm.c
> index 2d2092222d..cbd45e8095 100644
> --- a/libavcodec/agm.c
> +++ b/libavcodec/agm.c
> @@ -535,11 +535,13 @@ static int decode_frame(AVCodecContext *avctx, void
> *data,
>
>      s->flags = 0;
>      w = bytestream2_get_le32(gbyte);
> +    h = bytestream2_get_le32(gbyte);
> +    if (w == INT32_MIN || h == INT32_MIN)
> +        return AVERROR_INVALIDDATA;
>      if (w < 0) {
>          w = -w;
>          s->flags |= 2;
>      }
> -    h = bytestream2_get_le32(gbyte);
>      if (h < 0) {
>          h = -h;
>          s->flags |= 1;
> --

OK