commit cb50c54b31a83ac598530780fa8c145a3cb4a2de
author Chad Brubaker <cbrubaker@google.com> Wed Oct 07 14:20:10 2015 -0700
committer Chad Brubaker <cbrubaker@google.com> Mon Oct 12 13:37:09 2015 -0700
tree fcd28903c829729ebfc68ac3de7c1f0025e1da0d
parent 3cce4937ae9bb3a522bee74a47807c8cf0b462d5

Fix benign unsigned overflow in AuidoTrackShared

fsanitize=integer adds unsigned checks to int32_t - uint32_t, force both
operands to int32_t to avoid such checks being added.

Change-Id: I76fce38f9636f5322ad95fdb81abb690503f4d08

media/libmedia/AudioTrackShared.cpp

diff --git a/media/libmedia/AudioTrackShared.cpp b/media/libmedia/AudioTrackShared.cpp
index a5b516c..5e45c85 100644
--- a/media/libmedia/AudioTrackShared.cpp
+++ b/media/libmedia/AudioTrackShared.cpp
@@ -38,7 +38,7 @@
 // In general, this means (new_self) returned is max(self, other) + 1.
 
 static uint32_t incrementSequence(uint32_t self, uint32_t other) {
-    int32_t diff = (int32_t) self - other;
+    int32_t diff = (int32_t) self - (int32_t) other;
     if (diff >= 0 && diff < INT32_MAX) {
         return self + 1; // we're already ahead of other.
     }
@@ -894,7 +894,7 @@
     if (mObserver.poll(state)) {
         StaticAudioTrackState trystate = mState;
         bool result;
-        const int32_t diffSeq = state.mLoopSequence - state.mPositionSequence;
+        const int32_t diffSeq = (int32_t) state.mLoopSequence - (int32_t) state.mPositionSequence;
 
         if (diffSeq < 0) {
             result = updateStateWithLoop(&trystate, state) == OK &&