TCPConnection: Defer FailAndPrune by signaling to self

What steps will reproduce the problem?
1. Connect a TCPPort, creating a TCPConnection
2. Disconnect the interface (e.g turn it off in android)
3. Send Ping on the TCPConnection

Crash.
The TCPConnection calls FailAndPrune when it fails to reconnect
the TCPConnection. FailAndPrune which removes the StunRequests.
When this is called from the Ping() code,
that will still access the StunRequest after the call to the Connection.

Solution: Instead of calling FailAndPrune deep down in the Ping()-stack
post a message to self to do this with a "clean" stack instead.

BUG: webrtc:11315
Change-Id: Id328b1b7c92311fa5b9adbfd2eb1dd14bf19805d
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/167522
Commit-Queue: Jonas Oreland <jonaso@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Qingsi Wang <qingsi@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#30389}

p2p/base/port_unittest.cc

@@ -955,9 +955,7 @@ void PortTest::TestConnectivity(const char* name1,
 class FakePacketSocketFactory : public rtc::PacketSocketFactory {
  public:
   FakePacketSocketFactory()
-      : next_udp_socket_(NULL),
-        next_server_tcp_socket_(NULL),
-        next_client_tcp_socket_(NULL) {}
+      : next_udp_socket_(NULL), next_server_tcp_socket_(NULL) {}
   ~FakePacketSocketFactory() override {}
 
   AsyncPacketSocket* CreateUdpSocket(const SocketAddress& address,
@@ -985,9 +983,9 @@ class FakePacketSocketFactory : public rtc::PacketSocketFactory {
       const rtc::ProxyInfo& proxy_info,
       const std::string& user_agent,
       const rtc::PacketSocketTcpOptions& opts) override {
-    EXPECT_TRUE(next_client_tcp_socket_ != NULL);
-    AsyncPacketSocket* result = next_client_tcp_socket_;
-    next_client_tcp_socket_ = NULL;
+    EXPECT_TRUE(next_client_tcp_socket_.has_value());
+    AsyncPacketSocket* result = *next_client_tcp_socket_;
+    next_client_tcp_socket_ = nullptr;
     return result;
   }
 
@@ -1005,29 +1003,37 @@ class FakePacketSocketFactory : public rtc::PacketSocketFactory {
  private:
   AsyncPacketSocket* next_udp_socket_;
   AsyncPacketSocket* next_server_tcp_socket_;
-  AsyncPacketSocket* next_client_tcp_socket_;
+  absl::optional<AsyncPacketSocket*> next_client_tcp_socket_;
 };
 
 class FakeAsyncPacketSocket : public AsyncPacketSocket {
  public:
   // Returns current local address. Address may be set to NULL if the
   // socket is not bound yet (GetState() returns STATE_BINDING).
-  virtual SocketAddress GetLocalAddress() const { return SocketAddress(); }
+  virtual SocketAddress GetLocalAddress() const { return local_address_; }
 
   // Returns remote address. Returns zeroes if this is not a client TCP socket.
-  virtual SocketAddress GetRemoteAddress() const { return SocketAddress(); }
+  virtual SocketAddress GetRemoteAddress() const { return remote_address_; }
 
   // Send a packet.
   virtual int Send(const void* pv,
                    size_t cb,
                    const rtc::PacketOptions& options) {
-    return static_cast<int>(cb);
+    if (error_ == 0) {
+      return static_cast<int>(cb);
+    } else {
+      return -1;
+    }
   }
   virtual int SendTo(const void* pv,
                      size_t cb,
                      const SocketAddress& addr,
                      const rtc::PacketOptions& options) {
-    return static_cast<int>(cb);
+    if (error_ == 0) {
+      return static_cast<int>(cb);
+    } else {
+      return -1;
+    }
   }
   virtual int Close() { return 0; }
 
@@ -1035,11 +1041,15 @@ class FakeAsyncPacketSocket : public AsyncPacketSocket {
   virtual int GetOption(Socket::Option opt, int* value) { return 0; }
   virtual int SetOption(Socket::Option opt, int value) { return 0; }
   virtual int GetError() const { return 0; }
-  virtual void SetError(int error) {}
+  virtual void SetError(int error) { error_ = error; }
 
   void set_state(State state) { state_ = state; }
 
+  SocketAddress local_address_;
+  SocketAddress remote_address_;
+
  private:
+  int error_ = 0;
   State state_;
 };
 
@@ -1435,6 +1445,52 @@ TEST_F(PortTest, TestDelayedBindingTcp) {
   EXPECT_EQ(1U, port->Candidates().size());
 }
 
+TEST_F(PortTest, TestDisableInterfaceOfTcpPort) {
+  FakeAsyncPacketSocket* lsocket = new FakeAsyncPacketSocket();
+  FakeAsyncPacketSocket* rsocket = new FakeAsyncPacketSocket();
+  FakePacketSocketFactory socket_factory;
+
+  socket_factory.set_next_server_tcp_socket(lsocket);
+  auto lport = CreateTcpPort(kLocalAddr1, &socket_factory);
+
+  socket_factory.set_next_server_tcp_socket(rsocket);
+  auto rport = CreateTcpPort(kLocalAddr2, &socket_factory);
+
+  lsocket->set_state(AsyncPacketSocket::STATE_BINDING);
+  lsocket->SignalAddressReady(lsocket, kLocalAddr1);
+  rsocket->set_state(AsyncPacketSocket::STATE_BINDING);
+  rsocket->SignalAddressReady(rsocket, kLocalAddr2);
+
+  lport->SetIceRole(cricket::ICEROLE_CONTROLLING);
+  lport->SetIceTiebreaker(kTiebreaker1);
+  rport->SetIceRole(cricket::ICEROLE_CONTROLLED);
+  rport->SetIceTiebreaker(kTiebreaker2);
+
+  lport->PrepareAddress();
+  rport->PrepareAddress();
+  ASSERT_FALSE(rport->Candidates().empty());
+
+  // A client socket.
+  FakeAsyncPacketSocket* socket = new FakeAsyncPacketSocket();
+  socket->local_address_ = kLocalAddr1;
+  socket->remote_address_ = kLocalAddr2;
+  socket_factory.set_next_client_tcp_socket(socket);
+  Connection* lconn =
+      lport->CreateConnection(rport->Candidates()[0], Port::ORIGIN_MESSAGE);
+  ASSERT_NE(lconn, nullptr);
+  socket->SignalConnect(socket);
+  lconn->Ping(0);
+
+  // Now disconnect the client socket...
+  socket->SignalClose(socket, 1);
+
+  // And prevent new sockets from being created.
+  socket_factory.set_next_client_tcp_socket(nullptr);
+
+  // Test that Ping() does not cause SEGV.
+  lconn->Ping(0);
+}
+
 void PortTest::TestCrossFamilyPorts(int type) {
   FakePacketSocketFactory factory;
   std::unique_ptr<Port> ports[4];

p2p/base/tcp_port.cc

@@ -520,6 +520,9 @@ void TCPConnection::OnMessage(rtc::Message* pmsg) {
         Destroy();
       }
       break;
+    case MSG_TCPCONNECTION_FAILED_CREATE_SOCKET:
+      FailAndPrune();
+      break;
     default:
       Connection::OnMessage(pmsg);
   }
@@ -576,7 +579,13 @@ void TCPConnection::CreateOutgoingTcpSocket() {
   } else {
     RTC_LOG(LS_WARNING) << ToString() << ": Failed to create connection to "
                         << remote_candidate().address().ToSensitiveString();
-    FailAndPrune();
+    // We can't FailAndPrune directly here. FailAndPrune and deletes all
+    // the StunRequests from the request_map_. And if this is in the stack
+    // of Connection::Ping(), we are still using the request.
+    // Unwind the stack and defer the FailAndPrune.
+    set_state(IceCandidatePairState::FAILED);
+    port()->thread()->Post(RTC_FROM_HERE, this,
+                           MSG_TCPCONNECTION_FAILED_CREATE_SOCKET);
   }
 }
 

p2p/base/tcp_port.h

@@ -139,6 +139,7 @@ class TCPConnection : public Connection {
  protected:
   enum {
     MSG_TCPCONNECTION_DELAYED_ONCLOSE = Connection::MSG_FIRST_AVAILABLE,
+    MSG_TCPCONNECTION_FAILED_CREATE_SOCKET,
   };
 
   // Set waiting_for_stun_binding_complete_ to false to allow data packets in