[FFmpeg-devel] [PATCH 1/2] avformat/wtvdec: Check len in parse_chunks() to avoid overflow

[Michael Niedermayer]

On Tue, Feb 09, 2021 at 02:20:41AM +1100, Peter Ross wrote:
> On Mon, Feb 08, 2021 at 02:29:01PM +0100, Michael Niedermayer wrote:
> > Fixes: signed integer overflow: 2147483647 + 7 cannot be represented in type 'int'
> > Fixes: 30084/clusterfuzz-testcase-minimized-ffmpeg_dem_WTV_fuzzer-6192261941559296
> > 
> > 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/wtvdec.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/libavformat/wtvdec.c b/libavformat/wtvdec.c
> > index 6c41e3c1a3..7def9d2348 100644
> > --- a/libavformat/wtvdec.c
> > +++ b/libavformat/wtvdec.c
> > @@ -794,7 +794,7 @@ static int parse_chunks(AVFormatContext *s, int mode, int64_t seekts, int *len_p
> >  
> >          ff_get_guid(pb, &g);
> >          len = avio_rl32(pb);
> > -        if (len < 32) {
> > +        if (len < 32 || len > INT_MAX - 7) {
> >              int ret;
> >              if (avio_feof(pb))
> >                  return AVERROR_EOF;
> 
> the + 7 comes from WTV_PAD calculation

yes


> looks good

will apply

thx

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

Those who are best at talking, realize last or never when they are wrong.
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