NetworkChangeNotifierMac: lock access to network_reachable_ as it may be read

net/base/network_change_notifier_mac.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/base/network_change_notifier_mac.h"
 
 #include <netinet/in.h>
 #include <SystemConfiguration/SCDynamicStoreKey.h>
 #include <SystemConfiguration/SCNetworkReachability.h>
 #include <SystemConfiguration/SCSchemaDefinitions.h>
 
 #include "base/mac/scoped_cftyperef.h"
+#include "base/synchronization/lock.h"
 
 namespace net {
 
 NetworkChangeNotifierMac::NetworkChangeNotifierMac()
     : forwarder_(this),
       config_watcher_(&forwarder_),
       network_reachable_(true) {}
 
 NetworkChangeNotifierMac::~NetworkChangeNotifierMac() {
   if (reachability_.get() && run_loop_.get()) {
     SCNetworkReachabilityUnscheduleFromRunLoop(reachability_.get(),
                                                run_loop_.get(),
                                                kCFRunLoopCommonModes);
   }
 }
 
 bool NetworkChangeNotifierMac::IsCurrentlyOffline() const {
+  base::AutoLock lock(network_reachable_lock_);
   return !network_reachable_;
 }
 
 void NetworkChangeNotifierMac::SetDynamicStoreNotificationKeys(
     SCDynamicStoreRef store) {
   // Called on notifier thread.
   run_loop_.reset(CFRunLoopGetCurrent());
   CFRetain(run_loop_.get());
 
   base::mac::ScopedCFTypeRef<CFMutableArrayRef> notification_keys(
@@ skipping 73 matching lines @@
     SCNetworkConnectionFlags flags,
     void* notifier) {
   NetworkChangeNotifierMac* notifier_mac =
       static_cast<NetworkChangeNotifierMac*>(notifier);
 
   DCHECK_EQ(notifier_mac->run_loop_.get(), CFRunLoopGetCurrent());
 
   bool reachable = flags & kSCNetworkFlagsReachable;
   bool connection_required = flags & kSCNetworkFlagsConnectionRequired;
   bool old_reachability = notifier_mac->network_reachable_;
-  notifier_mac->network_reachable_ = reachable && !connection_required;
+  {
+    base::AutoLock lock(notifier_mac->network_reachable_lock_);
+    notifier_mac->network_reachable_ = reachable && !connection_required;
+  }
   if (old_reachability != notifier_mac->network_reachable_)
     NotifyObserversOfOnlineStateChange();
 }
 
 }  // namespace net