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| author | Ronald S. Bultje <rsbultje@gmail.com> | 2012-03-05 16:01:19 -0800 |
|---|---|---|
| committer | Ronald S. Bultje <rsbultje@gmail.com> | 2012-03-06 10:47:42 -0800 |
| commit | c23acbaed40101c677dfcfbbfe0d2c230a8e8f44 (patch) | |
| tree | 3fd50a826bbd6fb032f374c1eafd811ca3d8a642 /libavcodec/svq3.c | |
| parent | 2254b559cbcfc0418135f09add37c0a5866b1981 (diff) | |
| download | ffmpeg-c23acbaed40101c677dfcfbbfe0d2c230a8e8f44.tar.gz | |
Don't use ff_cropTbl[] for IDCT.
Results of IDCT can by far outreach the range of ff_cropTbl[], leading
to overreads and potentially crashes.
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable@libav.org
Diffstat (limited to 'libavcodec/svq3.c')
| -rw-r--r-- | libavcodec/svq3.c | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/libavcodec/svq3.c b/libavcodec/svq3.c index e157061f64..caafc49969 100644 --- a/libavcodec/svq3.c +++ b/libavcodec/svq3.c @@ -173,7 +173,6 @@ void ff_svq3_add_idct_c(uint8_t *dst, DCTELEM *block, int stride, int qp, { const int qmul = svq3_dequant_coeff[qp]; int i; - uint8_t *cm = ff_cropTbl + MAX_NEG_CROP; if (dc) { dc = 13*13*((dc == 1) ? 1538*block[0] : ((qmul*(block[0] >> 3)) / 2)); @@ -199,10 +198,10 @@ void ff_svq3_add_idct_c(uint8_t *dst, DCTELEM *block, int stride, int qp, const int z3 = 17* block[i + 4*1] + 7*block[i + 4*3]; const int rr = (dc + 0x80000); - dst[i + stride*0] = cm[ dst[i + stride*0] + (((z0 + z3)*qmul + rr) >> 20) ]; - dst[i + stride*1] = cm[ dst[i + stride*1] + (((z1 + z2)*qmul + rr) >> 20) ]; - dst[i + stride*2] = cm[ dst[i + stride*2] + (((z1 - z2)*qmul + rr) >> 20) ]; - dst[i + stride*3] = cm[ dst[i + stride*3] + (((z0 - z3)*qmul + rr) >> 20) ]; + dst[i + stride*0] = av_clip_uint8( dst[i + stride*0] + (((z0 + z3)*qmul + rr) >> 20) ); + dst[i + stride*1] = av_clip_uint8( dst[i + stride*1] + (((z1 + z2)*qmul + rr) >> 20) ); + dst[i + stride*2] = av_clip_uint8( dst[i + stride*2] + (((z1 - z2)*qmul + rr) >> 20) ); + dst[i + stride*3] = av_clip_uint8( dst[i + stride*3] + (((z0 - z3)*qmul + rr) >> 20) ); } } |