[FFmpeg-devel] [PATCH 2/3] avcodec/iff: Check length before memcpy() in decode_deep_rle32()

[Peter Ross]

On Tue, Apr 21, 2020 at 12:03:40AM +0200, Michael Niedermayer wrote:
> Fixes: out of array read
> Fixes: 20796/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_IFF_ILBM_fuzzer-5111364702175232.fuzz
> 
> 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/iff.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/libavcodec/iff.c b/libavcodec/iff.c
> index 2e65e266d0..23d19d8a25 100644
> --- a/libavcodec/iff.c
> +++ b/libavcodec/iff.c
> @@ -722,6 +722,8 @@ static void decode_deep_rle32(uint8_t *dst, const uint8_t *src, int src_size, in
>              int size = opcode + 1;
>              for (i = 0; i < size; i++) {
>                  int length = FFMIN(size - i, width);
> +                if (src_end - src < length)
> +                    return;
>                  memcpy(dst + y*linesize + x * 4, src, length * 4);
>                  src += length * 4;
>                  x += length;

hi michael.

i think the guard should be:

if (src_end - src < length * 4)
    return;

cheers,

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