[FFmpeg-cvslog] avcodec/aacdec_fixed: Fix multiple runtime error: shift exponent 127 is too large for 32-bit type 'int'

[Michael Niedermayer]

ffmpeg | branch: release/2.8 | Michael Niedermayer <michael at niedermayer.cc> | Sun May 28 03:34:09 2017 +0200| [7b1d93ce9ca2bbf05fcbbe3b5d52666311d6fd14] | committer: Michael Niedermayer

avcodec/aacdec_fixed: Fix multiple runtime error: shift exponent 127 is too large for 32-bit type 'int'

Fixes: 1851/clusterfuzz-testcase-minimized-5692607495667712

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 6c3a63fc3d1be7ac947e38a165a299c9e5d37764)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=7b1d93ce9ca2bbf05fcbbe3b5d52666311d6fd14
---

 libavcodec/aacdec_fixed.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/libavcodec/aacdec_fixed.c b/libavcodec/aacdec_fixed.c
index 2bd74293f3..0fcd350019 100644
--- a/libavcodec/aacdec_fixed.c
+++ b/libavcodec/aacdec_fixed.c
@@ -369,7 +369,9 @@ static void apply_dependent_coupling_fixed(AACContext *ac,
                     shift = (gain-1024) >> 3;
                 }
 
-                if (shift < 0) {
+                if (shift < -31) {
+                    // Nothing to do
+                } else if (shift < 0) {
                     shift = -shift;
                     round = 1 << (shift - 1);