[FFmpeg-cvslog] avcodec/wmavoice: Fix integer overflow in synth_frame()

[Michael Niedermayer]

ffmpeg | branch: release/3.4 | Michael Niedermayer <michael at niedermayer.cc> | Sat Nov  2 15:15:46 2019 +0100| [66e701af697da60553f2252ab617081b11672854] | committer: Michael Niedermayer

avcodec/wmavoice: Fix integer overflow in synth_frame()

Fixes: left shift of negative value -3
Fixes: 18518/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WMAVOICE_fuzzer-6560514359951360

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 cf323f4d38f5756ecdb8fb4f72c80a8069da832e)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=66e701af697da60553f2252ab617081b11672854
---

 libavcodec/wmavoice.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/wmavoice.c b/libavcodec/wmavoice.c
index 8871935315..abea3a6751 100644
--- a/libavcodec/wmavoice.c
+++ b/libavcodec/wmavoice.c
@@ -1519,7 +1519,7 @@ static int synth_frame(AVCodecContext *ctx, GetBitContext *gb, int frame_idx,
 
         /* "pitch-diff-per-sample" for calculation of pitch per sample */
         s->pitch_diff_sh16 =
-            ((cur_pitch_val - s->last_pitch_val) << 16) / MAX_FRAMESIZE;
+            (cur_pitch_val - s->last_pitch_val) * (1 << 16) / MAX_FRAMESIZE;
     }
 
     /* Global gain (if silence) and pitch-adaptive window coordinates */