[FFmpeg-devel] [PATCH 2/3] avcodec/exr: Fix overflow with many blocks

[Michael Niedermayer]

On Mon, Sep 28, 2020 at 04:13:00PM +0200, Michael Niedermayer wrote:
> On Sun, Sep 27, 2020 at 10:21:25AM +0200, Andreas Rheinhardt wrote:
> > Michael Niedermayer:
> > > Fixes: signed integer overflow: 1073741827 * 8 cannot be represented in type 'int'
> > > Fixes: 25621/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_EXR_fuzzer-6304841641754624
> > > 
> > > Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> > > Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> > > ---
> > >  libavcodec/exr.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/libavcodec/exr.c b/libavcodec/exr.c
> > > index c80e8eb5e0..8621a8cfe4 100644
> > > --- a/libavcodec/exr.c
> > > +++ b/libavcodec/exr.c
> > > @@ -1783,7 +1783,7 @@ static int decode_frame(AVCodecContext *avctx, void *data,
> > >      if ((ret = ff_thread_get_buffer(avctx, &frame, 0)) < 0)
> > >          return ret;
> > >  
> > > -    if (bytestream2_get_bytes_left(&s->gb) < nb_blocks * 8)
> > > +    if (bytestream2_get_bytes_left(&s->gb) < nb_blocks * 8L)
> > 
> > Does this have an advantage over dividing by 8?
> 
> probably not anything thats relevant in this case

will apply with a division

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The real ebay dictionary, page 1
"Used only once"    - "Some unspecified defect prevented a second use"
"In good condition" - "Can be repaird by experienced expert"
"As is" - "You wouldnt want it even if you were payed for it, if you knew ..."
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 195 bytes
Desc: not available
URL: <https://ffmpeg.org/pipermail/ffmpeg-devel/attachments/20201015/e80c2e9b/attachment.sig>