[FFmpeg-cvslog] avcodec/huffyuvdec: Fix undefined behavior with shift

Michael Niedermayer git at videolan.org
Thu Oct 19 14:31:15 EEST 2023


ffmpeg | branch: release/2.8 | Michael Niedermayer <michael at niedermayer.cc> | Sun Apr  9 13:18:42 2023 +0200| [a42455839aaea2b78de414eb6914b7d281173cbd] | committer: Michael Niedermayer

avcodec/huffyuvdec: Fix undefined behavior with shift

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>
(cherry picked from commit 27e7857bd1127974ffe1512293abee83b1035194)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=a42455839aaea2b78de414eb6914b7d281173cbd
---

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

diff --git a/libavcodec/huffyuvdec.c b/libavcodec/huffyuvdec.c
index 58b95f009f..36c37e0eb7 100644
--- a/libavcodec/huffyuvdec.c
+++ b/libavcodec/huffyuvdec.c
@@ -685,9 +685,9 @@ static void decode_422_bitstream(HYuvContext *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(HYuvContext *s, int width, int plane)



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