[FFmpeg-cvslog] opus_silk: fix typo causing overflow in silk_stabilize_lsf

[Andreas Cadhalpun]

ffmpeg | branch: release/2.4 | Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com> | Tue Dec 15 22:00:31 2015 +0100| [7a26ea7a7e67cff8c1f3367e4f505f1c650ca0f5] | committer: Andreas Cadhalpun

opus_silk: fix typo causing overflow in silk_stabilize_lsf

Due to this typo max_center can be too large, causing nlsf to be set to
too large values, which in turn can cause nlsf[i - 1] + min_delta[i] to
overflow to a negative value, which is not allowed for nlsf and can
cause an out of bounds read in silk_lsf2lpc.

Reviewed-by: Michael Niedermayer <michael at niedermayer.cc>
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com>
(cherry picked from commit f61d44b74aaae1d306d8a0d38b7b3d4292c89ced)
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=7a26ea7a7e67cff8c1f3367e4f505f1c650ca0f5
---

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

diff --git a/libavcodec/opus_silk.c b/libavcodec/opus_silk.c
index 7a89479..4c64cdf 100644
--- a/libavcodec/opus_silk.c
+++ b/libavcodec/opus_silk.c
@@ -824,7 +824,7 @@ static inline void silk_stabilize_lsf(int16_t nlsf[16], int order, const uint16_
 
             /* upper extent */
             for (i = order; i > k; i--)
-                max_center -= min_delta[k];
+                max_center -= min_delta[i];
             max_center -= min_delta[k] >> 1;
 
             /* move apart */