[FFmpeg-devel] [PATCH 5/7] avformat/mxfdec: More offset_temp checks

[Tomas Härdin]

sön 2024-09-15 klockan 22:28 +0200 skrev Tomas Härdin:
> fre 2024-09-13 klockan 01:33 +0200 skrev Michael Niedermayer:
> > Fixes: signed integer overflow: 9223372036854775807 - -
> > 1927491430256034080 cannot be represented in type 'long'
> > Fixes: 70607/clusterfuzz-testcase-minimized-ffmpeg_dem_MXF_fuzzer-
> > 5282235077951488
> > 
> > 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 | 5 +++++
> >  1 file changed, 5 insertions(+)
> > 
> > diff --git a/libavformat/mxfdec.c b/libavformat/mxfdec.c
> > index 8eae9f87afa..41281c5196d 100644
> > --- a/libavformat/mxfdec.c
> > +++ b/libavformat/mxfdec.c
> > @@ -1924,6 +1924,11 @@ static int
> > mxf_edit_unit_absolute_offset(MXFContext *mxf, MXFIndexTable
> > *index_t
> >              return mxf_absolute_bodysid_offset(mxf, index_table-
> > > body_sid, offset_temp, offset_out, partition_out);
> >          } else {
> >              /* EditUnitByteCount == 0 for VBR indexes, which is
> > fine
> > since they use explicit StreamOffsets */
> > +            if (s->edit_unit_byte_count &&  s->index_duration >
> > INT64_MAX / s->edit_unit_byte_count ||
> > +                s->edit_unit_byte_count * s->index_duration >
> > INT64_MAX - offset_temp
> > +            )
> > +                return AVERROR_INVALIDDATA;
> 
> Actually there's one minor issue: kdevelop warns about lack of
> parenthesis around the && and ||

It seems where the () are makes little difference, but I'm guessing we
want them around the || terms simply because that saves a few cycles

/Tomas