[FFmpeg-devel] [PATCH 2/3] avcodec/h274: fix bad left shifts

Michael Niedermayer michael at niedermayer.cc
Tue Sep 14 23:58:19 EEST 2021


Fixes: left shift of negative value -3
Fixes: 37788/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_H264_fuzzer-6024714540154880

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/h274.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavcodec/h274.c b/libavcodec/h274.c
index 262106733ce..20401ba06bb 100644
--- a/libavcodec/h274.c
+++ b/libavcodec/h274.c
@@ -250,8 +250,8 @@ int ff_h274_apply_film_grain(AVFrame *out_frame, const AVFrame *in_frame,
             // Adaptation for 4:2:0 chroma subsampling
             for (int i = 0; i < h274.num_intensity_intervals[c]; i++) {
                 h274.comp_model_value[c][i][0] >>= 1;
-                h274.comp_model_value[c][i][1] <<= 1;
-                h274.comp_model_value[c][i][2] <<= 1;
+                h274.comp_model_value[c][i][1] *= 2;
+                h274.comp_model_value[c][i][2] *= 2;
             }
         }
 
-- 
2.17.1



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