On Fri, Dec 23, 2022 at 12:47:02PM +0100, Tomas Härdin wrote: > fre 2022-12-23 klockan 00:25 +0100 skrev Michael Niedermayer: > > On Wed, Nov 16, 2022 at 12:49:10PM +0100, Tomas Härdin wrote: > > > sön 2022-11-13 klockan 00:44 +0100 skrev Michael Niedermayer: > > > > Fixes: signed integer overflow: -3741319169 - 9223372036823449370 > > > > cannot be represented in type 'long' > > > > Fixes: 51896/clusterfuzz-testcase-minimized- > > > > ffmpeg_dem_MXF_fuzzer- > > > > 513039428681728 > > > > > > > > Found-by: continuous fuzzing process > > > > https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg > > > > Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> > > > > --- > > > > libavformat/mxfdec.c | 10 +++++++--- > > > > 1 file changed, 7 insertions(+), 3 deletions(-) > > > > > > > > diff --git a/libavformat/mxfdec.c b/libavformat/mxfdec.c > > > > index e6118e141d..42109cb43a 100644 > > > > --- a/libavformat/mxfdec.c > > > > +++ b/libavformat/mxfdec.c > > > > @@ -100,7 +100,7 @@ typedef struct MXFPartition { > > > > uint64_t previous_partition; > > > > int index_sid; > > > > int body_sid; > > > > - int64_t this_partition; > > > > + uint64_t this_partition; > > > > int64_t essence_offset; ///< absolute offset of > > > > essence > > > > int64_t essence_length; > > > > int32_t kag_size; > > > > @@ -3519,8 +3519,12 @@ static void > > > > mxf_compute_essence_containers(AVFormatContext *s) > > > > p->essence_offset = p->first_essence_klv.offset; > > > > > > > > /* essence container spans to the next partition */ > > > > - if (x < mxf->partitions_count - 1) > > > > - p->essence_length = mxf- > > > > > partitions[x+1].this_partition - p->essence_offset; > > > > + if (x < mxf->partitions_count - 1) { > > > > + if (mxf->partitions[x+1].this_partition < p- > > > > > essence_offset) { > > > > + p->essence_length = -1; > > > > + } else > > > > + p->essence_length = mxf- > > > > > partitions[x+1].this_partition - p->essence_offset; > > > > + } > > > > > > A better solution might be to record the actual offset of the > > > partitions rather than relying on ThisPartition. Then we can > > > guarantee > > > that they are strictly increasing. > > > > do you mean that pack_ofs could be used here ? > > this_partition should be == pack_ofs - run_in. I think we can just nuke > this_partition in the struct and use pack_ofs - run_in everywhere. Emit > a warning or bail out if any partition does not obey this contraint, > since such files have likely been written by bad muxers.
ill post a patch doing that thx [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Elect your leaders based on what they did after the last election, not based on what they say before an election.
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