[FFmpeg-cvslog] avcodec/hevc_ps: check scaling_list_dc_coef

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Fri Dec 18 23:05:22 2020 +0100| [f1700bd8bb983bb3b56c3a1f8b9078cb62a44f65] | committer: Michael Niedermayer

avcodec/hevc_ps: check scaling_list_dc_coef

Fixes: signed integer overflow: 2147483640 + 8 cannot be represented in type 'int'
Fixes: 28449/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_HEVC_fuzzer-5686013259284480

Reviewed-by: James Almer <jamrial at gmail.com>
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=f1700bd8bb983bb3b56c3a1f8b9078cb62a44f65
---

 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)
+                        return AVERROR_INVALIDDATA;
+                    scaling_list_dc_coef[size_id - 2][matrix_id] = scaling_list_coeff_minus8 + 8;
                     next_coef = scaling_list_dc_coef[size_id - 2][matrix_id];
                     sl->sl_dc[size_id - 2][matrix_id] = next_coef;
                 }