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avcodec/h264idct_template: Fix multiple runtime error: signed integer overflow

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Fixes: 712/clusterfuzz-testcase-6647676227551232

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2017-03-24 03:09:32 +01:00
parent 73fb40dc87
commit 0ba22831e1
1 changed files with 24 additions and 24 deletions
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48
libavcodec/h264idct_template.c
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@ -107,34 +107,34 @@ void FUNCC(ff_h264_idct8_add)(uint8_t *_dst, int16_t *_block, int stride){
}
for( i = 0; i < 8; i++ )
{
const int a0 = block[0+i*8] + block[4+i*8];
const int a2 = block[0+i*8] - block[4+i*8];
const int a4 = (block[2+i*8]>>1) - block[6+i*8];
const int a6 = (block[6+i*8]>>1) + block[2+i*8];
const unsigned a0 = block[0+i*8] + block[4+i*8];
const unsigned a2 = block[0+i*8] - block[4+i*8];
const unsigned a4 = (block[2+i*8]>>1) - block[6+i*8];
const unsigned a6 = (block[6+i*8]>>1) + block[2+i*8];
const int b0 = a0 + a6;
const int b2 = a2 + a4;
const int b4 = a2 - a4;
const int b6 = a0 - a6;
const unsigned b0 = a0 + a6;
const unsigned b2 = a2 + a4;
const unsigned b4 = a2 - a4;
const unsigned b6 = a0 - a6;
const int a1 = -block[3+i*8] + block[5+i*8] - block[7+i*8] - (block[7+i*8]>>1);
const int a3 = block[1+i*8] + block[7+i*8] - block[3+i*8] - (block[3+i*8]>>1);
const int a5 = -block[1+i*8] + block[7+i*8] + block[5+i*8] + (block[5+i*8]>>1);
const int a7 = block[3+i*8] + block[5+i*8] + block[1+i*8] + (block[1+i*8]>>1);
const int a1 = -(unsigned)block[3+i*8] + block[5+i*8] - block[7+i*8] - (block[7+i*8]>>1);
const int a3 = (unsigned)block[1+i*8] + block[7+i*8] - block[3+i*8] - (block[3+i*8]>>1);
const int a5 = -(unsigned)block[1+i*8] + block[7+i*8] + block[5+i*8] + (block[5+i*8]>>1);
const int a7 = (unsigned)block[3+i*8] + block[5+i*8] + block[1+i*8] + (block[1+i*8]>>1);
const int b1 = (a7>>2) + a1;
const int b3 = a3 + (a5>>2);
const int b5 = (a3>>2) - a5;
const int b7 = a7 - (a1>>2);
const unsigned b1 = (a7>>2) + (unsigned)a1;
const unsigned b3 = (unsigned)a3 + (a5>>2);
const unsigned b5 = (a3>>2) - (unsigned)a5;
const unsigned b7 = (unsigned)a7 - (a1>>2);
dst[i + 0*stride] = av_clip_pixel( dst[i + 0*stride] + ((b0 + b7) >> 6) );
dst[i + 1*stride] = av_clip_pixel( dst[i + 1*stride] + ((b2 + b5) >> 6) );
dst[i + 2*stride] = av_clip_pixel( dst[i + 2*stride] + ((b4 + b3) >> 6) );
dst[i + 3*stride] = av_clip_pixel( dst[i + 3*stride] + ((b6 + b1) >> 6) );
dst[i + 4*stride] = av_clip_pixel( dst[i + 4*stride] + ((b6 - b1) >> 6) );
dst[i + 5*stride] = av_clip_pixel( dst[i + 5*stride] + ((b4 - b3) >> 6) );
dst[i + 6*stride] = av_clip_pixel( dst[i + 6*stride] + ((b2 - b5) >> 6) );
dst[i + 7*stride] = av_clip_pixel( dst[i + 7*stride] + ((b0 - b7) >> 6) );
dst[i + 0*stride] = av_clip_pixel( dst[i + 0*stride] + ((int)(b0 + b7) >> 6) );
dst[i + 1*stride] = av_clip_pixel( dst[i + 1*stride] + ((int)(b2 + b5) >> 6) );
dst[i + 2*stride] = av_clip_pixel( dst[i + 2*stride] + ((int)(b4 + b3) >> 6) );
dst[i + 3*stride] = av_clip_pixel( dst[i + 3*stride] + ((int)(b6 + b1) >> 6) );
dst[i + 4*stride] = av_clip_pixel( dst[i + 4*stride] + ((int)(b6 - b1) >> 6) );
dst[i + 5*stride] = av_clip_pixel( dst[i + 5*stride] + ((int)(b4 - b3) >> 6) );
dst[i + 6*stride] = av_clip_pixel( dst[i + 6*stride] + ((int)(b2 - b5) >> 6) );
dst[i + 7*stride] = av_clip_pixel( dst[i + 7*stride] + ((int)(b0 - b7) >> 6) );
}
memset(block, 0, 64 * sizeof(dctcoef));