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avcodec/apedec: Fix multiple integer overflows and undefined behaviorin filter_3800()

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Fixes: left shift of negative value -4
Fixes: signed integer overflow: -15091694 * 167 cannot be represented in type 'int'
Fixes: signed integer overflow: 1898547155 + 453967445 cannot be represented in type 'int'
Fixes: 15258/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_APE_fuzzer-5759095564402688
Fixes: signed integer overflow: 962196438 * 31 cannot be represented in type 'int'
Fixes: 15364/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_APE_fuzzer-5718799845687296

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 2019-06-16 11:39:15 +02:00
parent da5039415c
commit 267eb2ab7f
1 changed files with 5 additions and 5 deletions
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10
libavcodec/apedec.c
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@ -859,9 +859,9 @@ static av_always_inline int filter_3800(APEPredictor *p,
return predictionA;
}
d2 = p->buf[delayA];
d1 = (p->buf[delayA] - p->buf[delayA - 1]) << 1;
d0 = p->buf[delayA] + ((p->buf[delayA - 2] - p->buf[delayA - 1]) << 3);
d3 = p->buf[delayB] * 2 - p->buf[delayB - 1];
d1 = (p->buf[delayA] - p->buf[delayA - 1]) * 2U;
d0 = p->buf[delayA] + ((p->buf[delayA - 2] - p->buf[delayA - 1]) * 8U);
d3 = p->buf[delayB] * 2U - p->buf[delayB - 1];
d4 = p->buf[delayB];
predictionA = d0 * p->coeffsA[filter][0] +
@ -881,7 +881,7 @@ static av_always_inline int filter_3800(APEPredictor *p,
p->coeffsB[filter][1] -= (((d4 >> 30) & 2) - 1) * sign;
p->filterB[filter] = p->lastA[filter] + (predictionB >> shift);
p->filterA[filter] = p->filterB[filter] + ((p->filterA[filter] * 31) >> 5);
p->filterA[filter] = p->filterB[filter] + ((int)(p->filterA[filter] * 31U) >> 5);
return p->filterA[filter];
}
@ -902,7 +902,7 @@ static void long_filter_high_3800(int32_t *buffer, int order, int shift, int len
dotprod = 0;
sign = APESIGN(buffer[i]);
for (j = 0; j < order; j++) {
dotprod += delay[j] * coeffs[j];
dotprod += delay[j] * (unsigned)coeffs[j];
coeffs[j] += ((delay[j] >> 31) | 1) * sign;
}
buffer[i] -= dotprod >> shift;