backport: Prevent SEGFAULT when disabling listener (#13515) (#13882)

* Prevent SEGFAULT when disabling listener (#13515)

This prevents the stop_listening overload action from causing
segmentation faults that can occur if the action is enabled after the
listener has already shut down.

Signed-off-by: Alex Konradi <akonradi@google.com>
Signed-off-by: Christoph Pakulski <christoph@tetrate.io>

docs/root/version_history/current.rst

@@ -12,6 +12,7 @@ Minor Behavior Changes
 Bug Fixes
 ---------
 *Changes expected to improve the state of the world and are unlikely to have negative effects*
+* listener: fix crash when disabling or re-enabling listeners due to overload while processing LDS updates.
 
 Removed Config or Runtime
 -------------------------

docs/root/version_history/version_history.rst

@@ -7,6 +7,7 @@ Version history
   :titlesonly:
 
   current
+  v1.16.0
   v1.15.2
   v1.15.1
   v1.15.0

source/server/connection_handler_impl.cc

@@ -423,6 +423,18 @@ void ConnectionHandlerImpl::ActiveTcpListener::onAcceptWorker(
   }
 }
 
+void ConnectionHandlerImpl::ActiveTcpListener::pauseListening() {
+  if (listener_ != nullptr) {
+    listener_->disable();
+  }
+}
+
+void ConnectionHandlerImpl::ActiveTcpListener::resumeListening() {
+  if (listener_ != nullptr) {
+    listener_->enable();
+  }
+}
+
 void ConnectionHandlerImpl::ActiveTcpListener::newConnection(
     Network::ConnectionSocketPtr&& socket, std::unique_ptr<StreamInfo::StreamInfo> stream_info) {
   // Find matching filter chain.

source/server/connection_handler_impl.h

@@ -137,8 +137,8 @@ class ConnectionHandlerImpl : public Network::ConnectionHandler,
 
     // ActiveListenerImplBase
     Network::Listener* listener() override { return listener_.get(); }
-    void pauseListening() override { listener_->disable(); }
-    void resumeListening() override { listener_->enable(); }
+    void pauseListening() override;
+    void resumeListening() override;
     void shutdownListener() override { listener_.reset(); }
 
     // Network::BalancedConnectionHandler

test/server/connection_handler_test.cc

@@ -451,6 +451,22 @@ TEST_F(ConnectionHandlerTest, AddDisabledListener) {
   handler_->addListener(absl::nullopt, *test_listener);
 }
 
+TEST_F(ConnectionHandlerTest, DisableListenerAfterStop) {
+  InSequence s;
+
+  Network::TcpListenerCallbacks* listener_callbacks;
+  auto listener = new NiceMock<Network::MockListener>();
+  TestListener* test_listener =
+      addListener(1, false, false, "test_listener", listener, &listener_callbacks);
+  EXPECT_CALL(*socket_factory_, localAddress()).WillOnce(ReturnRef(local_address_));
+  handler_->addListener(absl::nullopt, *test_listener);
+
+  EXPECT_CALL(*listener, onDestroy());
+
+  handler_->stopListeners();
+  handler_->disableListeners();
+}
+
 TEST_F(ConnectionHandlerTest, DestroyCloseConnections) {
   InSequence s;