[FFmpeg-devel] [PATCH] avformat/ape: Error out in case of EOF in the header

[Michael Niedermayer]

On Sat, Jul 25, 2020 at 06:10:44AM +0200, Andreas Rheinhardt wrote:
> Michael Niedermayer:
> > Fixes: OOM
> > Fixes: 24375/clusterfuzz-testcase-minimized-ffmpeg_DEMUXER_fuzzer-6216862443241472
> > 
> > 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/ape.c | 8 +++++---
> >  1 file changed, 5 insertions(+), 3 deletions(-)
> > 
> > diff --git a/libavformat/ape.c b/libavformat/ape.c
> > index 39a584aa98..e966063ad7 100644
> > --- a/libavformat/ape.c
> > +++ b/libavformat/ape.c
> > @@ -253,7 +253,7 @@ static int ape_read_header(AVFormatContext * s)
> >              avio_skip(pb, ape->wavheaderlength);
> >      }
> >  
> > -    if(!ape->totalframes){
> > +    if(!ape->totalframes || pb->eof_reached){
> >          av_log(s, AV_LOG_ERROR, "No frames in the file!\n");
> >          return AVERROR(EINVAL);
> >      }
> > @@ -298,8 +298,10 @@ static int ape_read_header(AVFormatContext * s)
> >              for (i = 0; i < ape->totalframes && !pb->eof_reached; i++)
> >                  ape->bittable[i] = avio_r8(pb);
> >          }
> > -        if (pb->eof_reached)
> > -            av_log(s, AV_LOG_WARNING, "File truncated\n");
> > +        if (pb->eof_reached) {
> > +            av_log(s, AV_LOG_ERROR, "File truncated\n");
> > +            return AVERROR_INVALIDDATA;
> > +        }
> 
> The above will lead to a memleak as long as cleaning up on read_header
> failure is not automatic. Furthermore, it's the first of the checks that
> fixes the OOM scenario, not the second, isn't it?

yes, will apply with the leak issue fixed


> 
> - Andreas
> 
> PS: One could remove the allocations for seek- and bittable altogether;
> only ape_dumpinfo() needs to have the seektable, the bittable as well as
> the frames at the same time.

will post a patch doing that

thx

[...]
-- 
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/20200725/8e69cb69/attachment.sig>