Network: Defer deletion of client and server game socket handler

This fixes various use after free scenarios in error handling paths

src/network/core/tcp_game.cpp

@@ -21,6 +21,8 @@
 
 #include "../../safeguards.h"
 
+static std::vector<NetworkGameSocketHandler *> _deferred_deletions;
+
 static const char* _packet_game_type_names[] {
 	"SERVER_FULL",
 	"SERVER_BANNED",
@@ -290,3 +292,17 @@ void NetworkGameSocketHandler::LogSentPacket(const Packet &pkt)
 	PacketGameType type = (PacketGameType)pkt.GetPacketType();
 	DEBUG(net, 5, "[tcp/game] sent packet type %d (%s) to client %d, %s", type, GetPacketGameTypeName(type), this->client_id, this->GetDebugInfo().c_str());
 }
+
+void NetworkGameSocketHandler::DeferDeletion()
+{
+	_deferred_deletions.push_back(this);
+	this->is_pending_deletion = true;
+}
+
+/* static */ void NetworkGameSocketHandler::ProcessDeferredDeletions()
+{
+	for (NetworkGameSocketHandler *cs : _deferred_deletions) {
+		delete cs;
+	}
+	_deferred_deletions.clear();
+}

src/network/core/tcp_game.h

@@ -168,7 +168,8 @@ public:
 class NetworkGameSocketHandler : public NetworkTCPSocketHandler {
 /* TODO: rewrite into a proper class */
 private:
-	NetworkClientInfo *info;  ///< Client info related to this socket
+	NetworkClientInfo *info;          ///< Client info related to this socket
+	bool is_pending_deletion = false; ///< Whether this socket is pending deletion
 
 protected:
 	bool ignore_close = false;
@@ -592,6 +593,11 @@ public:
 
 	virtual std::string GetDebugInfo() const;
 	virtual void LogSentPacket(const Packet &pkt) override;
+
+	bool IsPendingDeletion() const { return this->is_pending_deletion; }
+
+	void DeferDeletion();
+	static void ProcessDeferredDeletions();
 };
 
 #endif /* NETWORK_CORE_TCP_GAME_H */