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avcodec/apedec: Fix integer overflows in predictor_update_3930() 

Fixes: signed integer overflow: 1074134419 - -1075212485 cannot be represented in type 'int'
Fixes: 43273/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_APE_fuzzer-4706880883130368

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2022-01-03 19:15:18 +01:00
parent 217c90aac7
commit 0c9c9bbd01
1 changed files with 8 additions and 8 deletions
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16
libavcodec/apedec.c
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@ -1088,13 +1088,13 @@ static av_always_inline int predictor_update_3930(APEPredictor *p,
const int delayA)
{
int32_t predictionA, sign;
int32_t d0, d1, d2, d3;
uint32_t d0, d1, d2, d3;
p->buf[delayA] = p->lastA[filter];
d0 = p->buf[delayA ];
d1 = p->buf[delayA ] - p->buf[delayA - 1];
d2 = p->buf[delayA - 1] - p->buf[delayA - 2];
d3 = p->buf[delayA - 2] - p->buf[delayA - 3];
d1 = p->buf[delayA ] - (unsigned)p->buf[delayA - 1];
d2 = p->buf[delayA - 1] - (unsigned)p->buf[delayA - 2];
d3 = p->buf[delayA - 2] - (unsigned)p->buf[delayA - 3];
predictionA = d0 * p->coeffsA[filter][0] +
d1 * p->coeffsA[filter][1] +
@ -1105,10 +1105,10 @@ static av_always_inline int predictor_update_3930(APEPredictor *p,
p->filterA[filter] = p->lastA[filter] + ((int)(p->filterA[filter] * 31U) >> 5);
sign = APESIGN(decoded);
p->coeffsA[filter][0] += ((d0 < 0) * 2 - 1) * sign;
p->coeffsA[filter][1] += ((d1 < 0) * 2 - 1) * sign;
p->coeffsA[filter][2] += ((d2 < 0) * 2 - 1) * sign;
p->coeffsA[filter][3] += ((d3 < 0) * 2 - 1) * sign;
p->coeffsA[filter][0] += (((int32_t)d0 < 0) * 2 - 1) * sign;
p->coeffsA[filter][1] += (((int32_t)d1 < 0) * 2 - 1) * sign;
p->coeffsA[filter][2] += (((int32_t)d2 < 0) * 2 - 1) * sign;
p->coeffsA[filter][3] += (((int32_t)d3 < 0) * 2 - 1) * sign;
return p->filterA[filter];
}