[FFmpeg-devel] [PATCH] avcodec/dirac_vlc: Fix integer overflow in ff_dirac_golomb_read_32bit()

[Lynne]

Apr 24, 2020, 23:04 by michael at niedermayer.cc:

> Fixes: left shift of 1073741824 by 1 places cannot be represented in type 'int32_t' (aka 'int')
> Fixes: 21245/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_DIRAC_fuzzer-5683334274613248
>
> 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/dirac_vlc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/libavcodec/dirac_vlc.c b/libavcodec/dirac_vlc.c
> index fbe28017bc..6d53078fc0 100644
> --- a/libavcodec/dirac_vlc.c
> +++ b/libavcodec/dirac_vlc.c
> @@ -1115,7 +1115,7 @@ int ff_dirac_golomb_read_32bit(const uint8_t *buf, int bytes,
>  {
>  LUTState lut = ff_dirac_golomb_lut[*buf++];
>  int32_t *dst = (int32_t *)_dst, *last = dst + coeffs;
> -    int32_t val = 0;
> +    uint32_t val = 0;
>  
>  for (int i = 1; i < bytes; i++)
>  PROCESS_VALS;
> -- 
> 2.17.1
>
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LGTM.
You should change the same variable in ff_dirac_golomb_read_16bit to a uint16_t too, to be safe.