On 16.06.2019, at 12:30, Lynne <d...@lynne.ee> wrote:
> Jun 16, 2019, 10:57 AM by mich...@niedermayer.cc: > >> 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 >> >> Found-by: continuous fuzzing process >> https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg >> Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> >> --- >> libavcodec/apedec.c | 16 ++++++++-------- >> 1 file changed, 8 insertions(+), 8 deletions(-) >> >> diff --git a/libavcodec/apedec.c b/libavcodec/apedec.c >> index 61ebfdafd5..f1bfc634c2 100644 >> --- a/libavcodec/apedec.c >> +++ b/libavcodec/apedec.c >> @@ -859,22 +859,22 @@ 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); >> + d1 = (p->buf[delayA] - p->buf[delayA - 1]) * 2; >> + d0 = p->buf[delayA] + ((p->buf[delayA - 2] - p->buf[delayA - 1]) * 8); >> d3 = p->buf[delayB] * 2 - p->buf[delayB - 1]; >> d4 = p->buf[delayB]; >> >> - predictionA = d0 * p->coeffsA[filter][0] + >> - d1 * p->coeffsA[filter][1] + >> - d2 * p->coeffsA[filter][2]; >> + predictionA = d0 * (unsigned)p->coeffsA[filter][0] + >> + d1 * (unsigned)p->coeffsA[filter][1] + >> + d2 * (unsigned)p->coeffsA[filter][2]; >> >> sign = APESIGN(decoded); >> p->coeffsA[filter][0] += (((d0 >> 30) & 2) - 1) * sign; >> p->coeffsA[filter][1] += (((d1 >> 28) & 8) - 4) * sign; >> p->coeffsA[filter][2] += (((d2 >> 28) & 8) - 4) * sign; >> >> - predictionB = d3 * p->coeffsB[filter][0] - >> - d4 * p->coeffsB[filter][1]; >> + predictionB = d3 * (unsigned)p->coeffsB[filter][0] - >> + d4 * (unsigned)p->coeffsB[filter][1]; >> p->lastA[filter] = decoded + (predictionA >> 11); >> sign = APESIGN(p->lastA[filter]); >> p->coeffsB[filter][0] += (((d3 >> 29) & 4) - 2) * sign; >> @@ -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; >> > > This code is DSP, overflows should be allowed in case input is corrupt. Then get the C standard changed or use a different language. But in C overflows on signed types absolutely are not Ok. _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
