On 6/16/19, Reimar Döffinger <reimar.doeffin...@gmx.de> wrote: > > > 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.
I disagree, overflows in DSP are normal. > _______________________________________________ > 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". _______________________________________________ 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".
