[FFmpeg-devel] [PATCH 3/4] avcodec/h264idct_template: Fix multiple runtime error: signed integer overflow

[Michael Niedermayer]

On Mon, Feb 27, 2017 at 07:15:57AM +0800, Steven Liu wrote:
> 2017-02-27 3:28 GMT+08:00 Michael Niedermayer <michael at niedermayer.cc>:
> 
> > Fixes: 677/clusterfuzz-testcase-6635120628858880
> >
> > 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/h264idct_template.c | 26 +++++++++++++-------------
> >  1 file changed, 13 insertions(+), 13 deletions(-)
> >
> > diff --git a/libavcodec/h264idct_template.c b/libavcodec/h264idct_
> > template.c
> > index c00900b658..9c5a43ce4f 100644
> > --- a/libavcodec/h264idct_template.c
> > +++ b/libavcodec/h264idct_template.c
> > @@ -40,10 +40,10 @@ void FUNCC(ff_h264_idct_add)(uint8_t *_dst, int16_t
> > *_block, int stride)
> >      block[0] += 1 << 5;
> >
> >      for(i=0; i<4; i++){
> > -        const int z0=  block[i + 4*0]     +  block[i + 4*2];
> > -        const int z1=  block[i + 4*0]     -  block[i + 4*2];
> > -        const int z2= (block[i + 4*1]>>1) -  block[i + 4*3];
> > -        const int z3=  block[i + 4*1]     + (block[i + 4*3]>>1);
> > +        const SUINT z0=  block[i + 4*0]     +  block[i + 4*2];
> > +        const SUINT z1=  block[i + 4*0]     -  block[i + 4*2];
> > +        const SUINT z2= (block[i + 4*1]>>1) -  block[i + 4*3];
> > +        const SUINT z3=  block[i + 4*1]     + (block[i + 4*3]>>1);
> >
> >          block[i + 4*0]= z0 + z3;
> >          block[i + 4*1]= z1 + z2;
> > @@ -52,15 +52,15 @@ void FUNCC(ff_h264_idct_add)(uint8_t *_dst, int16_t
> > *_block, int stride)
> >      }
> >
> >      for(i=0; i<4; i++){
> > -        const int z0=  block[0 + 4*i]     +  block[2 + 4*i];
> > -        const int z1=  block[0 + 4*i]     -  block[2 + 4*i];
> > -        const int z2= (block[1 + 4*i]>>1) -  block[3 + 4*i];
> > -        const int z3=  block[1 + 4*i]     + (block[3 + 4*i]>>1);
> > -
> > -        dst[i + 0*stride]= av_clip_pixel(dst[i + 0*stride] + ((z0 + z3)
> > >> 6));
> > -        dst[i + 1*stride]= av_clip_pixel(dst[i + 1*stride] + ((z1 + z2)
> > >> 6));
> > -        dst[i + 2*stride]= av_clip_pixel(dst[i + 2*stride] + ((z1 - z2)
> > >> 6));
> > -        dst[i + 3*stride]= av_clip_pixel(dst[i + 3*stride] + ((z0 - z3)
> > >> 6));
> > +        const SUINT z0=  block[0 + 4*i]     +  (SUINT)block[2 + 4*i];
> > +        const SUINT z1=  block[0 + 4*i]     -  (SUINT)block[2 + 4*i];
> > +        const SUINT z2= (block[1 + 4*i]>>1) -  (SUINT)block[3 + 4*i];
> > +        const SUINT z3=  block[1 + 4*i]     + (SUINT)(block[3 + 4*i]>>1);
> > +
> > +        dst[i + 0*stride]= av_clip_pixel(dst[i + 0*stride] + ((int)(z0 +
> > z3) >> 6));
> > +        dst[i + 1*stride]= av_clip_pixel(dst[i + 1*stride] + ((int)(z1 +
> > z2) >> 6));
> > +        dst[i + 2*stride]= av_clip_pixel(dst[i + 2*stride] + ((int)(z1 -
> > z2) >> 6));
> > +        dst[i + 3*stride]= av_clip_pixel(dst[i + 3*stride] + ((int)(z0 -
> > z3) >> 6));
> >      }
> >
> >      memset(block, 0, 16 * sizeof(dctcoef));
> > --
> > 2.11.0
> >
> > _______________________________________________
> > ffmpeg-devel mailing list
> > ffmpeg-devel at ffmpeg.org
> > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> >
> 
> lgtm

applied

also remaining patchset applied

thx

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Those who are too smart to engage in politics are punished by being
governed by those who are dumber. -- Plato 
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