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

[Michael Niedermayer]

On Sun, Feb 26, 2017 at 10:06:57AM +0100, Paul B Mahol wrote:
> On 2/25/17, Michael Niedermayer <michael at niedermayer.cc> wrote:
> > On Sat, Feb 25, 2017 at 10:00:36PM +0100, Paul B Mahol wrote:
> >> 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?
> >
> > in "sum >> qlevel" sum needs to be signed to get the correct
> > result
> >
> > I can also add a check for the overflow and return an error but thats
> > more code
> 
> no need, this is ok

applied

thx

[...]
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