[FFmpeg-devel] [PATCH 5/5] avcodec/flacdsp: Fix: runtime error: signed integer overflow: -1027555328 + -1226681270 cannot be represented in type 'int'

[Paul B Mahol]

On 2/25/17, Michael Niedermayer <michael at niedermayer.cc> wrote:
> Fixes: 673/clusterfuzz-testcase-5948736536576000
>
> Found-by: continuous fuzzing process
> https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg
> Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> ---
>  libavcodec/flacdsp.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/libavcodec/flacdsp.c b/libavcodec/flacdsp.c
> index 560091f73a..bc9a5dbed9 100644
> --- a/libavcodec/flacdsp.c
> +++ b/libavcodec/flacdsp.c
> @@ -67,7 +67,7 @@ static void flac_lpc_16_c(int32_t *decoded, const int
> coeffs[32],
>          int sum = 0;
>          for (j = 0; j < pred_order; j++)
>              sum += coeffs[j] * (SUINT)decoded[j];
> -        decoded[j] += sum >> qlevel;
> +        decoded[j] = decoded[j] + (unsigned)(sum >> qlevel);
>      }
>  }
>

What about making sum unsigned instead?