From 0ba22831e1fcc88c755190b08a9cfc235df3a9a9 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Fri, 24 Mar 2017 03:09:32 +0100 Subject: avcodec/h264idct_template: Fix multiple runtime error: signed integer overflow 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 --- libavcodec/h264idct_template.c | 56 +++++++++++++++++++++--------------------- 1 file changed, 28 insertions(+), 28 deletions(-) (limited to 'libavcodec') diff --git a/libavcodec/h264idct_template.c b/libavcodec/h264idct_template.c index 229a9ac36b..e1ef68756c 100644 --- a/libavcodec/h264idct_template.c +++ b/libavcodec/h264idct_template.c @@ -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 int b0 = a0 + a6; - const int b2 = a2 + a4; - const int b4 = a2 - a4; - const int 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 b1 = (a7>>2) + a1; - const int b3 = a3 + (a5>>2); - const int b5 = (a3>>2) - a5; - const int b7 = 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) ); + 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 unsigned b0 = a0 + a6; + const unsigned b2 = a2 + a4; + const unsigned b4 = a2 - a4; + const unsigned b6 = a0 - a6; + + 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 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] + ((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)); -- cgit v1.2.3