[FFmpeg-cvslog] avcodec/mv30: Fix several integer overflows in idct_1d()
Michael Niedermayer
git at videolan.org
Tue Sep 29 01:46:22 EEST 2020
ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sat Jul 25 23:35:03 2020 +0200| [ddf2ba54979387740b0b2fb319bb5a2c9f78debe] | committer: Michael Niedermayer
avcodec/mv30: Fix several integer overflows in idct_1d()
Fixes: signed integer overflow: -1846510390 + -361755993 cannot be represented in type 'int'
Fixes: 23941/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MV30_fuzzer-5654696631730176
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=ddf2ba54979387740b0b2fb319bb5a2c9f78debe
---
libavcodec/mv30.c | 34 +++++++++++++++++-----------------
1 file changed, 17 insertions(+), 17 deletions(-)
diff --git a/libavcodec/mv30.c b/libavcodec/mv30.c
index 0dcfef23e0..ff60be881d 100644
--- a/libavcodec/mv30.c
+++ b/libavcodec/mv30.c
@@ -104,23 +104,23 @@ static void get_qtable(int16_t *table, int quant, const uint8_t *quant_tab)
static inline void idct_1d(int *blk, int step)
{
- const int t0 = blk[0 * step] + blk[4 * step];
- const int t1 = blk[0 * step] - blk[4 * step];
- const int t2 = blk[2 * step] + blk[6 * step];
- const int t3 = ((int)((blk[2 * step] - blk[6 * step]) * 362U) >> 8) - t2;
- const int t4 = t0 + t2;
- const int t5 = t0 - t2;
- const int t6 = t1 + t3;
- const int t7 = t1 - t3;
- const int t8 = blk[5 * step] + blk[3 * step];
- const int t9 = blk[5 * step] - blk[3 * step];
- const int tA = blk[1 * step] + blk[7 * step];
- const int tB = blk[1 * step] - blk[7 * step];
- const int tC = t8 + tA;
- const int tD = (int)((tB + t9) * 473U) >> 8;
- const int tE = (((int)(t9 * -669U) >> 8) - tC) + tD;
- const int tF = ((int)((tA - t8) * 362U) >> 8) - tE;
- const int t10 = (((int)(tB * 277U) >> 8) - tD) + tF;
+ const unsigned t0 = blk[0 * step] + blk[4 * step];
+ const unsigned t1 = blk[0 * step] - blk[4 * step];
+ const unsigned t2 = blk[2 * step] + blk[6 * step];
+ const unsigned t3 = ((int)((blk[2 * step] - blk[6 * step]) * 362U) >> 8) - t2;
+ const unsigned t4 = t0 + t2;
+ const unsigned t5 = t0 - t2;
+ const unsigned t6 = t1 + t3;
+ const unsigned t7 = t1 - t3;
+ const unsigned t8 = blk[5 * step] + blk[3 * step];
+ const unsigned t9 = blk[5 * step] - blk[3 * step];
+ const unsigned tA = blk[1 * step] + blk[7 * step];
+ const unsigned tB = blk[1 * step] - blk[7 * step];
+ const unsigned tC = t8 + tA;
+ const unsigned tD = (int)((tB + t9) * 473U) >> 8;
+ const unsigned tE = (((int)(t9 * -669U) >> 8) - tC) + tD;
+ const unsigned tF = ((int)((tA - t8) * 362U) >> 8) - tE;
+ const unsigned t10 = (((int)(tB * 277U) >> 8) - tD) + tF;
blk[0 * step] = t4 + tC;
blk[1 * step] = t6 + tE;
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