Re: [FFmpeg-devel] [PATCH 6/6] avformat/mxfdec: Check body_offset

[Michael Niedermayer <michael@niedermayer.cc>]

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On Mon, Apr 29, 2024 at 10:25:33PM +0200, Tomas Härdin wrote:
> fre 2024-04-26 klockan 05:08 +0200 skrev Michael Niedermayer:
> > Fixes: signed integer overflow: 538976288 - -9223372036315799520
> > cannot be represented in type 'long'
> > Fixes: 68060/clusterfuzz-testcase-minimized-ffmpeg_dem_MXF_fuzzer-
> > 5523457266745344
> > 
> > Found-by: continuous fuzzing process
> > https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> > ---
> >  libavformat/mxfdec.c | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/libavformat/mxfdec.c b/libavformat/mxfdec.c
> > index 233d614f783..e65cec74c23 100644
> > --- a/libavformat/mxfdec.c
> > +++ b/libavformat/mxfdec.c
> > @@ -791,6 +791,9 @@ static int mxf_read_partition_pack(void *arg,
> > AVIOContext *pb, int tag, int size
> >      partition->index_sid = avio_rb32(pb);
> >      partition->body_offset = avio_rb64(pb);
> >      partition->body_sid = avio_rb32(pb);
> > +    if (partition->body_offset < 0)
> > +        return AVERROR_INVALIDDATA;
> 
> The spec says BodyOffset is UInt64, so this means we drop support for
> files >= 2^63 bytes. This is probably fine though. Supporting such
> large files would be a pain in more places than here.
> 
> MXF is sometimes used to archive scanned copies of film, but even raw
> 16k rgb48 essence @ 120 Hz takes over 1000 days of footage to hit the
> 2^63 limit..
> 
> I took a look at the body_offset logic and it looks like it should be
> correct when we force them to be non-negative.
> 
> TL;DR: looks OK

will apply
will also apply 2,3,5 of this set

thanks

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

I have never wished to cater to the crowd; for what I know they do not
approve, and what they approve I do not know. -- Epicurus

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