[FFmpeg-devel] [PATCH 4/4] avcodec/jpeg2000dec: Check PLT data somewhat

[Michael Niedermayer]

On Thu, Apr 25, 2019 at 04:34:00PM +0000, Andreas Rheinhardt wrote:
> Michael Niedermayer:
> > Fixes: Timeout (21sec -> 0.6sec)
> > Fixes: 14134/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_JPEG2000_fuzzer-5768371078955008
> > 
> > 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/jpeg2000dec.c | 8 +++++++-
> >  1 file changed, 7 insertions(+), 1 deletion(-)
> > 
> > diff --git a/libavcodec/jpeg2000dec.c b/libavcodec/jpeg2000dec.c
> > index 9198cf87cb..62b0b1f9b7 100644
> > --- a/libavcodec/jpeg2000dec.c
> > +++ b/libavcodec/jpeg2000dec.c
> > @@ -832,15 +832,21 @@ static uint8_t get_tlm(Jpeg2000DecoderContext *s, int n)
> >  static uint8_t get_plt(Jpeg2000DecoderContext *s, int n)
> >  {
> >      int i;
> > +    int v;
> >  
> >      av_log(s->avctx, AV_LOG_DEBUG,
> >              "PLT marker at pos 0x%X\n", bytestream2_tell(&s->g) - 4);
> >  
> > +    if (n < 4)
> > +        return AVERROR_INVALIDDATA;
> > +
> >      /*Zplt =*/ bytestream2_get_byte(&s->g);
> >  
> >      for (i = 0; i < n - 3; i++) {
> > -        bytestream2_get_byte(&s->g);
> > +        v = bytestream2_get_byte(&s->g);
> >      }
> > +    if (v & 0x80)
> > +        return AVERROR_INVALIDDATA;
> >  
> >      return 0;
> >  }
> > 
> get_tlm should probably return int as uint8_t can't hold the
> AVERROR_INVALIDDATA. gcc gives Woverflow warnings because of that.
> 
> Currently, the return value of get_tlm is always >= 0 and so is the
> return value of jpeg2000_read_main_headers and of
> jpeg2000_decode_frame if one runs into the AVERROR_INVALIDDATA checks.
> (I didn't test it, just took a quick glimpse at the code.)

will fix

thanks

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

If you fake or manipulate statistics in a paper in physics you will never
get a job again.
If you fake or manipulate statistics in a paper in medicin you will get
a job for life at the pharma industry.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 181 bytes
Desc: not available
URL: <http://ffmpeg.org/pipermail/ffmpeg-devel/attachments/20190425/82b785b8/attachment.sig>