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

Paul B Mahol onemda at gmail.com
Mon Feb 5 11:04:47 EET 2018


On 2/5/18, Michael Niedermayer <michael at niedermayer.cc> wrote:
> 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

Are you sure this does not break decoding of valid files?


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