[FFmpeg-devel] [PATCH 3/3] avcodec/huffyuvdec: Check input buffer size

[Michael Niedermayer]

On Thu, Feb 01, 2018 at 02:36:16AM +0100, Michael Niedermayer wrote:
> On Wed, Jan 31, 2018 at 07:56:06PM +0100, Paul B Mahol wrote:
> > On 1/31/18, Michael Niedermayer <michael at niedermayer.cc> wrote:
> > > Fixes: Timeout
> > > Fixes: 5487/clusterfuzz-testcase-4696837035393024
> > >
> > > 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/huffyuvdec.c | 3 +++
> > >  1 file changed, 3 insertions(+)
> > >
> > > diff --git a/libavcodec/huffyuvdec.c b/libavcodec/huffyuvdec.c
> > > index 979c4b9d5c..66357bfb40 100644
> > > --- a/libavcodec/huffyuvdec.c
> > > +++ b/libavcodec/huffyuvdec.c
> > > @@ -919,6 +919,9 @@ static int decode_frame(AVCodecContext *avctx, void
> > > *data, int *got_frame,
> > >      AVFrame *const p = data;
> > >      int table_size = 0, ret;
> > >
> > > +    if (buf_size < (width * height + 7)/8)
> > > +        return AVERROR_INVALIDDATA;
> > > +
> > 
> > Are you sure this is enough?
> 
> I dont know if thats the only way the decoder can be made to waste
> large amounts of CPU with little input data
> 
> I do belive it stops this specific class of issues though
> 
> 
> > 
> > Something similar you had already posted long ago.
> 
> for other decoders, yes. Did i forget a patch for huffyuv ?

i will apply this in a few days unless someone has objections or
sees some possible imrpovment

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Asymptotically faster algorithms should always be preferred if you have
asymptotical amounts of data
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