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| author | Michael Niedermayer <michael@niedermayer.cc> | 2020-05-02 21:25:17 +0200 |
|---|---|---|
| committer | Michael Niedermayer <michael@niedermayer.cc> | 2020-05-21 09:31:08 +0200 |
| commit | 620236e4d2ac46821911b99fa4551868675d4ed9 (patch) | |
| tree | dfb2e9af0c10cb6b38b52b193bd326254e6ad98d /libavcodec/xvididct.c | |
| parent | e9a4c4fe9918220be492a4a9d74c2293fd706be3 (diff) | |
avcodec/xvididct: Fix integer overflow in idct_row()
Fixes: signed integer overflow: -1238335488 + -1003634688 cannot be represented in type 'int'
Fixes: 21649/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MJPEG_fuzzer-5112005765890048
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
Diffstat (limited to 'libavcodec/xvididct.c')
| -rw-r--r-- | libavcodec/xvididct.c | 36 |
1 files changed, 18 insertions, 18 deletions
diff --git a/libavcodec/xvididct.c b/libavcodec/xvididct.c index 14116bd6d3..360deb3244 100644 --- a/libavcodec/xvididct.c +++ b/libavcodec/xvididct.c @@ -115,24 +115,24 @@ static int idct_row(short *in, const int *const tab, int rnd) in[6] = a1; } else { const int k = c4 * in[0] + rnd; - const int a0 = k + c2 * in[2] + c4 * in[4] + c6 * in[6]; - const int a1 = k + c6 * in[2] - c4 * in[4] - c2 * in[6]; - const int a2 = k - c6 * in[2] - c4 * in[4] + c2 * in[6]; - const int a3 = k - c2 * in[2] + c4 * in[4] - c6 * in[6]; - - const int b0 = c1 * in[1] + c3 * in[3] + c5 * in[5] + c7 * in[7]; - const int b1 = c3 * in[1] - c7 * in[3] - c1 * in[5] - c5 * in[7]; - const int b2 = c5 * in[1] - c1 * in[3] + c7 * in[5] + c3 * in[7]; - const int b3 = c7 * in[1] - c5 * in[3] + c3 * in[5] - c1 * in[7]; - - in[0] = (a0 + b0) >> ROW_SHIFT; - in[1] = (a1 + b1) >> ROW_SHIFT; - in[2] = (a2 + b2) >> ROW_SHIFT; - in[3] = (a3 + b3) >> ROW_SHIFT; - in[4] = (a3 - b3) >> ROW_SHIFT; - in[5] = (a2 - b2) >> ROW_SHIFT; - in[6] = (a1 - b1) >> ROW_SHIFT; - in[7] = (a0 - b0) >> ROW_SHIFT; + const unsigned int a0 = k + c2 * in[2] + c4 * in[4] + c6 * in[6]; + const unsigned int a1 = k + c6 * in[2] - c4 * in[4] - c2 * in[6]; + const unsigned int a2 = k - c6 * in[2] - c4 * in[4] + c2 * in[6]; + const unsigned int a3 = k - c2 * in[2] + c4 * in[4] - c6 * in[6]; + + const unsigned int b0 = c1 * in[1] + c3 * in[3] + c5 * in[5] + c7 * in[7]; + const unsigned int b1 = c3 * in[1] - c7 * in[3] - c1 * in[5] - c5 * in[7]; + const unsigned int b2 = c5 * in[1] - c1 * in[3] + c7 * in[5] + c3 * in[7]; + const unsigned int b3 = c7 * in[1] - c5 * in[3] + c3 * in[5] - c1 * in[7]; + + in[0] = (int)(a0 + b0) >> ROW_SHIFT; + in[1] = (int)(a1 + b1) >> ROW_SHIFT; + in[2] = (int)(a2 + b2) >> ROW_SHIFT; + in[3] = (int)(a3 + b3) >> ROW_SHIFT; + in[4] = (int)(a3 - b3) >> ROW_SHIFT; + in[5] = (int)(a2 - b2) >> ROW_SHIFT; + in[6] = (int)(a1 - b1) >> ROW_SHIFT; + in[7] = (int)(a0 - b0) >> ROW_SHIFT; } return 1; } |