commit 0ff2b4cd4265a1a3453c42f6ce7ae4220ec08ff1
author Ivo Creusen <ivoc@webrtc.org> Wed Dec 16 16:37:58 2020
committer Commit Bot <commit-bot@chromium.org> Thu Dec 17 11:06:01 2020
tree 7b6c17b71a766ebb7cbd90e7b7610ccdbdf4772d
parent c25a3a3a1e95d0dff27336c1ba9be0fb1019e6ee

Fix for overflow in iLBC code.

The calculation of the necessary number of shifts is not correct, leading to an overflow.

Bug: chromium:1158070
Change-Id: I6545e9da46debf33ce169c33d762915fe755d606
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/197981
Reviewed-by: Henrik Lundin <henrik.lundin@webrtc.org>
Commit-Queue: Ivo Creusen <ivoc@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32855}

modules/audio_coding/codecs/ilbc/enhancer_interface.c

diff --git a/modules/audio_coding/codecs/ilbc/enhancer_interface.c b/modules/audio_coding/codecs/ilbc/enhancer_interface.c
index f85df6d7..74dfebb 100644
--- a/modules/audio_coding/codecs/ilbc/enhancer_interface.c
+++ b/modules/audio_coding/codecs/ilbc/enhancer_interface.c
@@ -202,10 +202,10 @@
 
     /* scaling */
     max16 = WebRtcSpl_MaxAbsValueW16(regressor, plc_blockl + 3 - 1);
-    if (max16>5000)
-      shifts=2;
-    else
-      shifts=0;
+
+    const int64_t max_val = plc_blockl * max16 * max16;
+    const int32_t factor = max_val >> 31;
+    shifts = factor == 0 ? 0 : 31 - WebRtcSpl_NormW32(factor);
 
     /* compute cross correlation */
     WebRtcSpl_CrossCorrelation(corr32, target, regressor, plc_blockl, 3, shifts,