[FFmpeg-devel] [PATCH 5/8] avcodec/hevc_ps: check scaling_list_dc_coef

[Michael Niedermayer]

On Fri, Dec 18, 2020 at 08:45:32PM -0300, James Almer wrote:
> On 12/18/2020 8:22 PM, Michael Niedermayer wrote:
> > Fixes: signed integer overflow: 2147483640 + 8 cannot be represented in type 'int'
> > Fixes: 28449/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_HEVC_fuzzer-5686013259284480
> > 
> > Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> > ---
> >   libavcodec/hevc_ps.c | 6 +++++-
> >   1 file changed, 5 insertions(+), 1 deletion(-)
> > 
> > diff --git a/libavcodec/hevc_ps.c b/libavcodec/hevc_ps.c
> > index ea6fd536c6..139f3deeda 100644
> > --- a/libavcodec/hevc_ps.c
> > +++ b/libavcodec/hevc_ps.c
> > @@ -816,7 +816,11 @@ static int scaling_list_data(GetBitContext *gb, AVCodecContext *avctx, ScalingLi
> >                   next_coef = 8;
> >                   coef_num  = FFMIN(64, 1 << (4 + (size_id << 1)));
> >                   if (size_id > 1) {
> > -                    scaling_list_dc_coef[size_id - 2][matrix_id] = get_se_golomb(gb) + 8;
> > +                    int scaling_list_coeff_minus8 = get_se_golomb(gb);
> > +                    if (scaling_list_coeff_minus8 < -7 ||
> > +                        scaling_list_coeff_minus8 > 247)
> 
> LGTM, this check is also done in CBS so i assume it's taken from the spec.

yes

> 
> > +                        return AVERROR_INVALIDDATA;
> > +                    scaling_list_dc_coef[size_id - 2][matrix_id] = scaling_list_coeff_minus8 + 8;
> 
> Not strictly related to this patch, but this array could be made into an
> uint8_t now.

yes, will change that too

thx

[...]
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