[FFmpeg-devel] [PATCH 1/6] avcodec/huffyuvdec: Fix undefined behavior with shift

[Michael Niedermayer]

Fixes: left shift of negative value -1
Fixes: 57554/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_FFVHUFF_fuzzer-4853603839115264

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 | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavcodec/huffyuvdec.c b/libavcodec/huffyuvdec.c
index 7d3515cc889..8ba67bbdeb5 100644
--- a/libavcodec/huffyuvdec.c
+++ b/libavcodec/huffyuvdec.c
@@ -695,9 +695,9 @@ static void decode_422_bitstream(HYuvDecContext *s, int count)
 /* TODO instead of restarting the read when the code isn't in the first level
  * of the joint table, jump into the 2nd level of the individual table. */
 #define READ_2PIX_PLANE16(dst0, dst1, plane){\
-    dst0 = get_vlc2(&s->gb, s->vlc[plane].table, VLC_BITS, 3)<<2;\
+    dst0 = get_vlc2(&s->gb, s->vlc[plane].table, VLC_BITS, 3)*4;\
     dst0 += get_bits(&s->gb, 2);\
-    dst1 = get_vlc2(&s->gb, s->vlc[plane].table, VLC_BITS, 3)<<2;\
+    dst1 = get_vlc2(&s->gb, s->vlc[plane].table, VLC_BITS, 3)*4;\
     dst1 += get_bits(&s->gb, 2);\
 }
 static void decode_plane_bitstream(HYuvDecContext *s, int width, int plane)
-- 
2.17.1