[FFmpeg-devel] [PATCH 3/4] avformat/mxfdec: Ensure klv->key is initialized

[Tomas Härdin]

tor 2025-07-24 klockan 00:51 +0200 skrev Marton Balint:
> 
> 
> On Wed, 23 Jul 2025, Tomas Härdin wrote:
> 
> > ons 2025-07-23 klockan 13:45 +0200 skrev Michael Niedermayer:
> > > Fixes: read of uninitialized memory
> > > Fixes: 391916474/clusterfuzz-testcase-minimized-
> > > ffmpeg_dem_MXF_fuzzer-4935250956845056
> > > 
> > > Found-by: continuous fuzzing process
> > > https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> > > Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> > > ---
> > >  libavformat/mxfdec.c | 4 +++-
> > >  1 file changed, 3 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/libavformat/mxfdec.c b/libavformat/mxfdec.c
> > > index 0eed13d850d..184e97256cd 100644
> > > --- a/libavformat/mxfdec.c
> > > +++ b/libavformat/mxfdec.c
> > > @@ -491,7 +491,9 @@ static int klv_read_packet(MXFContext *mxf,
> > > KLVPacket *klv, AVIOContext *pb)
> > >          return AVERROR_INVALIDDATA;
> > >  
> > >      memcpy(klv->key, mxf_klv_key, 4);
> > > -    avio_read(pb, klv->key + 4, 12);
> > > +    int ret = ffio_read_size(pb, klv->key + 4, 12);
> > > +    if (ret < 0)
> > > +        return ret;
> > 
> > ret != 12 is better. If it's non-negative then return AVERROR_EOF
> 
> ffio_read_size always returns the requested size or negative.

Herp. Well in that case it's fine yes

/Tomas