Quoting Michael Niedermayer (2021-01-19 19:00:47) > On Mon, Jan 18, 2021 at 09:06:10PM +0100, Anton Khirnov wrote: > > Quoting Michael Niedermayer (2021-01-17 00:07:26) > > > Fixes: signed integer overflow: 80 * 92233009 cannot be represented in > > > type 'int' > > > Fixes: > > > 26910/clusterfuzz-testcase-minimized-ffmpeg_dem_NISTSPHERE_fuzzer-6669100654919680 > > > > > > Found-by: continuous fuzzing process > > > https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg > > > Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> > > > --- > > > libavformat/nistspheredec.c | 4 +++- > > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > > > diff --git a/libavformat/nistspheredec.c b/libavformat/nistspheredec.c > > > index 079369929f..fec5c88892 100644 > > > --- a/libavformat/nistspheredec.c > > > +++ b/libavformat/nistspheredec.c > > > @@ -80,7 +80,9 @@ static int nist_read_header(AVFormatContext *s) > > > > > > avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate); > > > > > > - st->codecpar->block_align = > > > st->codecpar->bits_per_coded_sample * st->codecpar->channels / 8; > > > + if (st->codecpar->bits_per_coded_sample * > > > (uint64_t)st->codecpar->channels / 8 > INT_MAX) > > > + return AVERROR_INVALIDDATA; > > > + st->codecpar->block_align = > > > st->codecpar->bits_per_coded_sample * (uint64_t)st->codecpar->channels / > > > 8; > > > > > > if (avio_tell(s->pb) > header_size) > > > return AVERROR_INVALIDDATA; > > > -- > > > 2.17.1 > > > > Both bits_per_coded_sample and channels seem to be arbitrary ints, so > > you are assuming sizeof(int) < sizeof(int64) > > I wonder if we shouldnt limit these 2 fields in a platform independant way > But if we dont then the change below should do more correct checks
I would be in favor of limiting them both to 16 bits, that should be way beyond anything needed by any reasonable use case. > > @@ -80,7 +80,11 @@ static int nist_read_header(AVFormatContext *s) > > avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate); > > - st->codecpar->block_align = st->codecpar->bits_per_coded_sample > * st->codecpar->channels / 8; > + if (st->codecpar->bits_per_coded_sample < 0 || > st->codecpar->channels <= 0 || > + st->codecpar->bits_per_coded_sample > UINT64_MAX / > st->codecpar->channels || > + st->codecpar->bits_per_coded_sample * > (uint64_t)st->codecpar->channels / 8 > INT_MAX) > + return AVERROR_INVALIDDATA; > + st->codecpar->block_align = st->codecpar->bits_per_coded_sample > * (uint64_t)st->codecpar->channels / 8; > > if (avio_tell(s->pb) > header_size) > return AVERROR_INVALIDDATA; This looks ok. Though it would be even better to sanity-check each value for zero/negative right after the sscanf() that reads it (not insisting you do it). -- Anton Khirnov _______________________________________________ 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".
