[FFmpeg-devel] [PATCH v3] avformat/mxfdec: Remove this_partition

[Tomas Härdin]

ons 2023-09-27 klockan 23:12 +0200 skrev Michael Niedermayer:
> Hi
> 
> On Wed, Sep 27, 2023 at 01:37:40PM +0200, Tomas Härdin wrote:
> > fre 2023-09-22 klockan 21:13 +0200 skrev Michael Niedermayer:
> > > Suggested-by: Tomas Härdin <git at haerdin.se>
> > > Fixes: 51896/clusterfuzz-testcase-minimized-
> > > ffmpeg_dem_MXF_fuzzer-
> > > 5130394286817280
> > > 
> > > Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> > > ---
> > >  libavformat/mxfdec.c | 28 ++++++++++++++++++----------
> > >  1 file changed, 18 insertions(+), 10 deletions(-)
> > > 
> > > diff --git a/libavformat/mxfdec.c b/libavformat/mxfdec.c
> > > index 4846c5d206a..1313f14fa03 100644
> > > --- a/libavformat/mxfdec.c
> > > +++ b/libavformat/mxfdec.c
> > > @@ -102,7 +102,6 @@ typedef struct MXFPartition {
> > >      uint64_t previous_partition;
> > >      int index_sid;
> > >      int body_sid;
> > > -    int64_t this_partition;
> > >      int64_t essence_offset;         ///< absolute offset of
> > > essence
> > >      int64_t essence_length;
> > >      int32_t kag_size;
> > > @@ -727,10 +726,13 @@ static int mxf_read_partition_pack(void
> > > *arg,
> > > AVIOContext *pb, int tag, int size
> > >      UID op;
> > >      uint64_t footer_partition;
> > >      uint32_t nb_essence_containers;
> > > +    uint64_t this_partition;
> > >  
> > >      if (mxf->partitions_count >= INT_MAX / 2)
> > >          return AVERROR_INVALIDDATA;
> > >  
> > > +    av_assert0(klv_offset >= mxf->run_in);
> > > +
> > >      tmp_part = av_realloc_array(mxf->partitions, mxf-
> > > > partitions_count + 1, sizeof(*mxf->partitions));
> > >      if (!tmp_part)
> > >          return AVERROR(ENOMEM);
> > > @@ -773,7 +775,13 @@ static int mxf_read_partition_pack(void
> > > *arg,
> > > AVIOContext *pb, int tag, int size
> > >      partition->complete = uid[14] > 2;
> > >      avio_skip(pb, 4);
> > >      partition->kag_size = avio_rb32(pb);
> > > -    partition->this_partition = avio_rb64(pb);
> > > +    this_partition = avio_rb64(pb);
> > > +    if (this_partition != klv_offset - mxf->run_in) {
> > > +        av_log(mxf->fc, AV_LOG_WARNING,
> > > +               "this_partition %"PRId64" mismatches
> > > %"PRId64"\n",
> > > +               this_partition, klv_offset - mxf->run_in);
> > 
> > We might want to error out here, since this means offsets are
> > likely to
> > be incorrect across the entire file. We have no files in FATE that
> > demonstrate this problem, and it pays to be strict when it comes to
> > MXF. This helps people writing new MXF muxers from writing broken
> > ones.
> 
> ok, should i ask for a sample here (so we maybe get a sample)
> or just error out with this message at AV_LOG_ERROR ?

Nah, just error out

/Tomas