[FFmpeg-devel] [PATCH 1/5] avcodec/binkaudio: Check sample rate

[Michael Niedermayer]

On Fri, Oct 11, 2019 at 08:51:54PM +1100, Peter Ross wrote:
> On Fri, Oct 11, 2019 at 12:40:07AM +0200, Michael Niedermayer wrote:
> > Fixes: signed integer overflow: 1092624416 * 2 cannot be represented in type 'int'
> > Fixes: 18045/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_BINKAUDIO_RDFT_fuzzer-5718519492116480
> > 
> > Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> > Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> > ---
> >  libavcodec/binkaudio.c | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/libavcodec/binkaudio.c b/libavcodec/binkaudio.c
> > index 96cf968c66..2384ebf312 100644
> > --- a/libavcodec/binkaudio.c
> > +++ b/libavcodec/binkaudio.c
> > @@ -95,6 +95,8 @@ static av_cold int decode_init(AVCodecContext *avctx)
> >      if (avctx->codec->id == AV_CODEC_ID_BINKAUDIO_RDFT) {
> >          // audio is already interleaved for the RDFT format variant
> >          avctx->sample_fmt = AV_SAMPLE_FMT_FLT;
> > +        if (sample_rate > INT_MAX / avctx->channels)
> > +            return AVERROR_INVALIDDATA;
> >          sample_rate  *= avctx->channels;
> >          s->channels = 1;
> >          if (!s->version_b)
> > -- 
> > 2.23.0
> 
> i think this checl belongs inside the fuzzer test harness, or as a general
> purpose codec check.
> 
> the bink and smaker demuxers will only ever use BINKAUDIO_RDFT with 1 or 2 channels.

In the case of the overflow channels was 2

what check do you suggest to be done in general code ?
A check specific to the fuzzer would fail to prevent this from happening
outside the fuzzer

Thanks

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Frequently ignored answer#1 FFmpeg bugs should be sent to our bugtracker. User
questions about the command line tools should be sent to the ffmpeg-user ML.
And questions about how to use libav* should be sent to the libav-user ML.
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