[FFmpeg-cvslog] avcodec/adpcm: Fix invalid shift in xa_decode()

[Michael Niedermayer]

ffmpeg | branch: release/2.8 | Michael Niedermayer <michael at niedermayer.cc> | Wed Nov 20 19:13:09 2019 +0100| [bf94919fc02b49f09639f36308796a0361eef988] | committer: Michael Niedermayer

avcodec/adpcm: Fix invalid shift in xa_decode()

Fixes: left shift of negative value -1
Fixes: 18859/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_ADPCM_XA_fuzzer-5748474213040128

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 50db30b47d016fc4e7b47067545b15d22d4faddf)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=bf94919fc02b49f09639f36308796a0361eef988
---

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

diff --git a/libavcodec/adpcm.c b/libavcodec/adpcm.c
index e7cf2210ed..9354e57158 100644
--- a/libavcodec/adpcm.c
+++ b/libavcodec/adpcm.c
@@ -367,7 +367,7 @@ static int xa_decode(AVCodecContext *avctx, int16_t *out0, int16_t *out1,
             d = in[16+i+j*4];
 
             t = sign_extend(d, 4);
-            s = ( t<<shift ) + ((s_1*f0 + s_2*f1+32)>>6);
+            s = t*(1<<shift) + ((s_1*f0 + s_2*f1+32)>>6);
             s_2 = s_1;
             s_1 = av_clip_int16(s);
             out0[j] = s_1;
@@ -394,7 +394,7 @@ static int xa_decode(AVCodecContext *avctx, int16_t *out0, int16_t *out1,
             d = in[16+i+j*4];
 
             t = sign_extend(d >> 4, 4);
-            s = ( t<<shift ) + ((s_1*f0 + s_2*f1+32)>>6);
+            s = t*(1<<shift) + ((s_1*f0 + s_2*f1+32)>>6);
             s_2 = s_1;
             s_1 = av_clip_int16(s);
             out1[j] = s_1;