On Mon, Jul 27, 2020 at 09:55:31AM +0530, Gautam Ramakrishnan wrote: > On Mon, Jul 27, 2020 at 9:48 AM Gautam Ramakrishnan > <gautamr...@gmail.com> wrote: > > > > On Mon, Jul 27, 2020 at 3:16 AM Michael Niedermayer > > <mich...@niedermayer.cc> wrote: > > > > > > Fixes: division by zero > > > Fixes: > > > 24201/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_JPEG2000_fuzzer-5665813827420160 > > > Fixes: > > > 24245/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_JPEG2000_fuzzer-6285831682392064 > > > > > > Found-by: continuous fuzzing process > > > https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg > > > Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> > > > --- > > > libavcodec/jpeg2000dec.c | 6 +++--- > > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > > > diff --git a/libavcodec/jpeg2000dec.c b/libavcodec/jpeg2000dec.c > > > index a470cf47da..b168e52db6 100644 > > > --- a/libavcodec/jpeg2000dec.c > > > +++ b/libavcodec/jpeg2000dec.c > > > @@ -1401,12 +1401,12 @@ static int > > > jpeg2000_decode_packets_po_iteration(Jpeg2000DecoderContext *s, Jpeg2 > > > if (!s->cdx[compno] || !s->cdy[compno]) > > > return AVERROR_INVALIDDATA; > > > > > > - trx0 = ff_jpeg2000_ceildiv(tile->coord[0][0], > > > s->cdx[compno] << reducedresno); > > > - try0 = ff_jpeg2000_ceildiv(tile->coord[1][0], > > > s->cdy[compno] << reducedresno); > > > - > > > if (reslevelno >= codsty->nreslevels) > > > continue; > > > > > > + trx0 = ff_jpeg2000_ceildiv(tile->coord[0][0], > > > s->cdx[compno] << reducedresno); > > > + try0 = ff_jpeg2000_ceildiv(tile->coord[1][0], > > > s->cdy[compno] << reducedresno); > > > + > > > if (!(y % ((uint64_t)s->cdy[compno] << > > > (rlevel->log2_prec_height + reducedresno)) == 0 || > > > (y == tile->coord[1][0] && (try0 << > > > reducedresno) % (1U << (reducedresno + rlevel->log2_prec_height))))) > > > continue; > > > -- > > > 2.17.1 > > > > > > _______________________________________________ > > > 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". > > > > Looks good to me. > > I guess the division by zero happens because shifting by reducedresno > > overflows?
yes > > > > -- > > ------------- > > Gautam | > Just realized, this might happen in one more place, shall send a > patch for the same. yes thx [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Dictatorship naturally arises out of democracy, and the most aggravated form of tyranny and slavery out of the most extreme liberty. -- Plato
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