From 9024da84c9a4c3f4358f310d4be5df37723ec70c Mon Sep 17 00:00:00 2001
From: Henrik Lundin <henrik.lundin@webrtc.org>
Date: Mon, 21 May 2018 13:41:16 +0200
Subject: [PATCH] NetEq: Fixing an overflow bug in expand.cc

The overflow currently does not cause any problems, but it has been
found that it can cause crashes after a refactoring that is coming in
the near future.

Bug: webrtc:9180
Change-Id: Ia2c4e545c062c4f8ad13cbc47b8796c6e8a4e906
Reviewed-on: https://webrtc-review.googlesource.com/77667
Reviewed-by: Ivo Creusen <ivoc@webrtc.org>
Commit-Queue: Henrik Lundin <henrik.lundin@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23327}
---
 modules/audio_coding/neteq/expand.cc         |  6 +++---
 modules/audio_coding/neteq/neteq_unittest.cc | 12 ++++++------
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/modules/audio_coding/neteq/expand.cc b/modules/audio_coding/neteq/expand.cc
index 03bcc77ff0..73e8d07e0d 100644
--- a/modules/audio_coding/neteq/expand.cc
+++ b/modules/audio_coding/neteq/expand.cc
@@ -743,9 +743,9 @@ void Expand::AnalyzeSignal(int16_t* random_vector) {
       // the division.
       // Shift the denominator from Q13 to Q5 before the division. The result of
       // the division will then be in Q20.
-      int temp_ratio = WebRtcSpl_DivW32W16(
-          (slope - 8192) << 12,
-          static_cast<int16_t>((distortion_lag * slope) >> 8));
+      int16_t denom =
+          rtc::saturated_cast<int16_t>((distortion_lag * slope) >> 8);
+      int temp_ratio = WebRtcSpl_DivW32W16((slope - 8192) << 12, denom);
       if (slope > 14746) {
         // slope > 1.8.
         // Divide by 2, with proper rounding.
diff --git a/modules/audio_coding/neteq/neteq_unittest.cc b/modules/audio_coding/neteq/neteq_unittest.cc
index 4cd3014b38..42dbcf3536 100644
--- a/modules/audio_coding/neteq/neteq_unittest.cc
+++ b/modules/audio_coding/neteq/neteq_unittest.cc
@@ -502,15 +502,15 @@ TEST_F(NetEqDecodingTest, MAYBE_TestOpusBitExactness) {
       webrtc::test::ResourcePath("audio_coding/neteq_opus", "rtp");
 
   const std::string output_checksum = PlatformChecksum(
-      "7ea28d7edf9395f4ac8e8d8dd3a9e5c620b1bf48",
-      "5b1e691ab1c4465c742d6d944bc71e3b1c0e4c0e",
-      "b096114dd8c233eaf2b0ce9802ac95af13933772",
-      "7ea28d7edf9395f4ac8e8d8dd3a9e5c620b1bf48",
-      "7ea28d7edf9395f4ac8e8d8dd3a9e5c620b1bf48");
+      "e0e4063d55941792a725fde1f781ebbbe83b8165",
+      "b77d2f25db1e59e054160a89e7defc7bfdb12f31",
+      "a8a525c476a922456a35b5b13861b55cd8c9c7b8",
+      "e0e4063d55941792a725fde1f781ebbbe83b8165",
+      "e0e4063d55941792a725fde1f781ebbbe83b8165");
 
   const std::string network_stats_checksum =
       PlatformChecksum("9e72233c78baf685e500dd6c94212b30a4c5f27d",
-                       "9a37270e4242fbd31e80bb47dc5e7ab82cf2d557",
+                       "c237d7ca04cbb1ea2e3b27a7c8963015deb985e7",
                        "4f1e9734bc80a290faaf9d611efcb8d7802dbc4f",
                        "9e72233c78baf685e500dd6c94212b30a4c5f27d",
                        "9e72233c78baf685e500dd6c94212b30a4c5f27d");