Replace HTTP auth server with Atlas connectionless packet

5 files changed, 41 insertions, 123 deletions

diff --git a/NorthstarDLL/server/auth/serverauthentication.cpp b/NorthstarDLL/server/auth/serverauthentication.cpp
index 4d9eb19f..8f62e1dd 100644
--- a/NorthstarDLL/server/auth/serverauthentication.cpp
+++ b/NorthstarDLL/server/auth/serverauthentication.cpp
@@ -14,104 +14,30 @@
 #include "client/r2client.h"
 #include "server/r2server.h"
 
-#include "httplib.h"
-
 #include <fstream>
 #include <filesystem>
+#include <string>
 #include <thread>
 
 AUTOHOOK_INIT()
 
-const char* AUTHSERVER_VERIFY_STRING = "I am a northstar server!";
-
 // global vars
 ServerAuthenticationManager* g_pServerAuthentication;
 CBaseServer__RejectConnectionType CBaseServer__RejectConnection;
 
-void ServerAuthenticationManager::StartPlayerAuthServer()
+void ServerAuthenticationManager::AddRemotePlayer(std::string token, uint64_t uid, std::string username, std::string pdata)
 {
-	if (m_bRunningPlayerAuthThread)
-	{
-		spdlog::warn("ServerAuthenticationManager::StartPlayerAuthServer was called while m_bRunningPlayerAuthThread is true");
-		return;
-	}
-
-	g_pServerPresence->SetAuthPort(Cvar_ns_player_auth_port->GetInt()); // set auth port for presence
-	m_bRunningPlayerAuthThread = true;
-
-	// listen is a blocking call so thread this
-	std::thread serverThread(
-		[this]
-		{
-			// this is just a super basic way to verify that servers have ports open, masterserver will try to read this before ensuring
-			// server is legit
-			m_PlayerAuthServer.Get(
-				"/verify",
-				[](const httplib::Request& request, httplib::Response& response)
-				{ response.set_content(AUTHSERVER_VERIFY_STRING, "text/plain"); });
-
-			m_PlayerAuthServer.Post(
-				"/authenticate_incoming_player",
-				[this](const httplib::Request& request, httplib::Response& response)
-				{
-					if (!request.has_param("id") || !request.has_param("authToken") || request.body.size() >= R2::PERSISTENCE_MAX_SIZE ||
-						!request.has_param("serverAuthToken") ||
-						strcmp(g_pMasterServerManager->m_sOwnServerAuthToken, request.get_param_value("serverAuthToken").c_str()))
-					{
-						response.set_content("{\"success\":false}", "application/json");
-						return;
-					}
-
-					uint64_t uid;
-					try
-					{
-						uid = std::strtoull(request.get_param_value("id").c_str(), nullptr, 10);
-					}
-					catch (std::exception const& ex)
-					{
-						response.set_content("{\"success\":false}", "application/json");
-						return;
-					}
-					if (!g_pBanSystem->IsUIDAllowed(uid))
-					{
-						response.set_content("{\"success\":false,\"reject\":\"Banned from this server.\"}", "application/json");
-						return;
-					}
-
-					RemoteAuthData newAuthData {};
-					strncpy_s(newAuthData.uid, sizeof(newAuthData.uid), request.get_param_value("id").c_str(), sizeof(newAuthData.uid) - 1);
-					strncpy_s(
-						newAuthData.username,
-						sizeof(newAuthData.username),
-						request.get_param_value("username").c_str(),
-						sizeof(newAuthData.username) - 1);
-
-					newAuthData.pdataSize = request.body.size();
-					newAuthData.pdata = new char[newAuthData.pdataSize];
-					memcpy(newAuthData.pdata, request.body.c_str(), newAuthData.pdataSize);
-
-					std::lock_guard<std::mutex> guard(m_AuthDataMutex);
-					m_RemoteAuthenticationData.insert(std::make_pair(request.get_param_value("authToken"), newAuthData));
-
-					response.set_content("{\"success\":true}", "application/json");
-				});
-
-			m_PlayerAuthServer.listen("0.0.0.0", Cvar_ns_player_auth_port->GetInt());
-		});
-
-	serverThread.detach();
-}
+	std::string uidS = std::to_string(uid);
 
-void ServerAuthenticationManager::StopPlayerAuthServer()
-{
-	if (!m_bRunningPlayerAuthThread)
-	{
-		spdlog::warn("ServerAuthenticationManager::StopPlayerAuthServer was called while m_bRunningPlayerAuthThread is false");
-		return;
-	}
+	RemoteAuthData newAuthData {};
+	strncpy_s(newAuthData.uid, sizeof(newAuthData.uid), uidS.c_str(), uidS.length());
+	strncpy_s(newAuthData.username, sizeof(newAuthData.username), username.c_str(), username.length());
+	newAuthData.pdata = new char[pdata.length()];
+	newAuthData.pdataSize = pdata.length();
+	memcpy(newAuthData.pdata, pdata.c_str(), newAuthData.pdataSize);
 
-	m_bRunningPlayerAuthThread = false;
-	m_PlayerAuthServer.stop();
+	std::lock_guard<std::mutex> guard(m_AuthDataMutex);
+	m_RemoteAuthenticationData[token] = newAuthData;
 }
 
 void ServerAuthenticationManager::AddPlayer(R2::CBaseClient* pPlayer, const char* pToken)
@@ -323,11 +249,11 @@ bool,, (R2::CBaseClient* self, char* pName, void* pNetChannel, char bFakePlayer,
 	if (!bFakePlayer)
 	{
 		if (!g_pServerAuthentication->VerifyPlayerName(pNextPlayerToken, pName, pVerifiedName))
-			pAuthenticationFailure = "Invalid name.";
+			pAuthenticationFailure = "Invalid Name.";
 		else if (!g_pBanSystem->IsUIDAllowed(iNextPlayerUid))
-			pAuthenticationFailure = "Banned from this server.";
+			pAuthenticationFailure = "Banned From server.";
 		else if (!g_pServerAuthentication->CheckAuthentication(self, iNextPlayerUid, pNextPlayerToken))
-			pAuthenticationFailure = "Authentication failed.";
+			pAuthenticationFailure = "Authentication Failed.";
 	}
 	else // need to copy name for bots still
 		strncpy_s(pVerifiedName, pName, 63);
@@ -423,7 +349,6 @@ ON_DLL_LOAD_RELIESON("engine.dll", ServerAuthentication, (ConCommand, ConVar), (
 
 	g_pServerAuthentication = new ServerAuthenticationManager;
 
-	g_pServerAuthentication->Cvar_ns_player_auth_port = new ConVar("ns_player_auth_port", "8081", FCVAR_GAMEDLL, "");
 	g_pServerAuthentication->Cvar_ns_erase_auth_info =
 		new ConVar("ns_erase_auth_info", "1", FCVAR_GAMEDLL, "Whether auth info should be erased from this server on disconnect or crash");
 	g_pServerAuthentication->Cvar_ns_auth_allow_insecure =
diff --git a/NorthstarDLL/server/auth/serverauthentication.h b/NorthstarDLL/server/auth/serverauthentication.h
index 2ca07a8a..dd0e13af 100644
--- a/NorthstarDLL/server/auth/serverauthentication.h
+++ b/NorthstarDLL/server/auth/serverauthentication.h
@@ -1,6 +1,5 @@
 #pragma once
 #include "core/convar/convar.h"
-#include "httplib.h"
 #include "engine/r2engine.h"
 #include <unordered_map>
 #include <string>
@@ -27,11 +26,7 @@ extern CBaseServer__RejectConnectionType CBaseServer__RejectConnection;
 
 class ServerAuthenticationManager
 {
-  private:
-	httplib::Server m_PlayerAuthServer;
-
   public:
-	ConVar* Cvar_ns_player_auth_port;
 	ConVar* Cvar_ns_erase_auth_info;
 	ConVar* Cvar_ns_auth_allow_insecure;
 	ConVar* Cvar_ns_auth_allow_insecure_write;
@@ -41,14 +36,12 @@ class ServerAuthenticationManager
 	std::unordered_map<R2::CBaseClient*, PlayerAuthenticationData> m_PlayerAuthenticationData;
 
 	bool m_bAllowDuplicateAccounts = false;
-	bool m_bRunningPlayerAuthThread = false;
 	bool m_bNeedLocalAuthForNewgame = false;
 	bool m_bForceResetLocalPlayerPersistence = false;
 	bool m_bStartingLocalSPGame = false;
 
   public:
-	void StartPlayerAuthServer();
-	void StopPlayerAuthServer();
+	void AddRemotePlayer(std::string token, uint64_t uid, std::string username, std::string pdata);
 
 	void AddPlayer(R2::CBaseClient* pPlayer, const char* pAuthToken);
 	void RemovePlayer(R2::CBaseClient* pPlayer);
diff --git a/NorthstarDLL/server/servernethooks.cpp b/NorthstarDLL/server/servernethooks.cpp
index c367c1e1..905d3251 100644
--- a/NorthstarDLL/server/servernethooks.cpp
+++ b/NorthstarDLL/server/servernethooks.cpp
@@ -12,8 +12,8 @@ AUTOHOOK_INIT()
 static ConVar* Cvar_net_debug_atlas_packet;
 static ConVar* Cvar_net_debug_atlas_packet_insecure;
 
-#define HMACSHA256_LEN (256 / 8)
-BCRYPT_ALG_HANDLE HMACSHA256;
+static BCRYPT_ALG_HANDLE HMACSHA256;
+constexpr size_t HMACSHA256_LEN = 256 / 8;
 
 static bool InitHMACSHA256()
 {
@@ -42,13 +42,10 @@ static bool InitHMACSHA256()
 	return true;
 }
 
-// note: all Atlas connectionless packets should be idempotent so multiple attempts can be made to mitigate packet loss
-// note: all long-running Atlas connectionless packet handlers should be started in a new thread (with copies of the data) to avoid blocking
-// networking
-
+// compare the HMAC-SHA256(data, key) against sig (note: all strings are treated as raw binary data)
 static bool VerifyHMACSHA256(std::string key, std::string sig, std::string data)
 {
-	bool result = false;
+	uint8_t invalid = 1;
 	char hash[HMACSHA256_LEN];
 
 	NTSTATUS status;
@@ -72,18 +69,21 @@ static bool VerifyHMACSHA256(std::string key, std::string sig, std::string data)
 		goto cleanup;
 	}
 
-	if (std::string(hash, sizeof(hash)) == sig)
+	// constant-time compare
+	if (sig.length() == sizeof(hash))
 	{
-		result = true;
-		goto cleanup;
+		invalid = 0;
+		for (size_t i = 0; i < sizeof(hash); i++)
+			invalid |= (uint8_t)(sig[i]) ^ (uint8_t)(hash[i]);
 	}
 
 cleanup:
 	if (h)
 		BCryptDestroyHash(h);
-	return result;
+	return !invalid;
 }
 
+// v1 HMACSHA256-signed masterserver request (HMAC-SHA256(JSONData, MasterServerToken) + JSONData)
 static void ProcessAtlasConnectionlessPacketSigreq1(R2::netpacket_t* packet, bool dbg, std::string pType, std::string pData)
 {
 	if (pData.length() < HMACSHA256_LEN)
@@ -129,7 +129,7 @@ static void ProcessAtlasConnectionlessPacketSigreq1(R2::netpacket_t* packet, boo
 	if (dbg)
 		spdlog::info("got Atlas connectionless packet (size={} type={} data={})", packet->size, pType, pData);
 
-	std::thread t([pData] { g_pMasterServerManager->ProcessConnectionlessPacketSigreq1(pData); });
+	std::thread t(&MasterServerManager::ProcessConnectionlessPacketSigreq1, g_pMasterServerManager, pData);
 	t.detach();
 
 	return;
@@ -152,6 +152,10 @@ static void ProcessAtlasConnectionlessPacket(R2::netpacket_t* packet)
 		}
 	}
 
+	// note: all Atlas connectionless packets should be idempotent so multiple attempts can be made to mitigate packet loss
+	// note: all long-running Atlas connectionless packet handlers should be started in a new thread (with copies of the data) to avoid
+	// blocking networking
+
 	// v1 HMACSHA256-signed masterserver request
 	if (pType == "sigreq1")
 	{
@@ -166,13 +170,22 @@ static void ProcessAtlasConnectionlessPacket(R2::netpacket_t* packet)
 
 AUTOHOOK(ProcessConnectionlessPacket, engine.dll + 0x117800, bool, , (void* a1, R2::netpacket_t* packet))
 {
+	// packet->data consists of 0xFFFFFFFF (int32 -1) to indicate packets aren't split, followed by a header consisting of a single
+	// character, which is used to uniquely identify the packet kind. Most kinds follow this with a null-terminated string payload
+	// then an arbitrary amoount of data.
+
+	// T (no rate limits since we authenticate packets before doing anything expensive)
 	if (4 < packet->size && packet->data[4] == 'T')
 	{
 		ProcessAtlasConnectionlessPacket(packet);
 		return false;
 	}
+
+	// check rate limits for the original unconnected packets
 	if (!g_pServerLimits->CheckConnectionlessPacketLimits(packet))
 		return false;
+
+	// A, H, I, N
 	return ProcessConnectionlessPacket(a1, packet);
 }
 
@@ -202,7 +215,4 @@ ON_DLL_LOAD_RELIESON("engine.dll", ServerNetHooks, ConVar, (CModule module))
 		"0",
 		FCVAR_NONE,
 		"Whether to disable signature verification for Atlas connectionless packets (DANGEROUS: this allows anyone to impersonate Atlas)");
-
-	if (Cvar_net_debug_atlas_packet_insecure->GetBool())
-		spdlog::warn("DANGEROUS: Atlas connectionless packet signature verification disabled; anyone will be able to impersonate Atlas");
 }
diff --git a/NorthstarDLL/server/serverpresence.cpp b/NorthstarDLL/server/serverpresence.cpp
index e0b29cb6..945f5810 100644
--- a/NorthstarDLL/server/serverpresence.cpp
+++ b/NorthstarDLL/server/serverpresence.cpp
@@ -106,9 +106,8 @@ void ServerPresenceManager::AddPresenceReporter(ServerPresenceReporter* reporter
 void ServerPresenceManager::CreatePresence()
 {
 	// reset presence fields that rely on runtime server state
-	// these being: port/auth port, map/playlist name, and playercount/maxplayers
+	// these being: port, map/playlist name, and playercount/maxplayers
 	m_ServerPresence.m_iPort = 0;
-	m_ServerPresence.m_iAuthPort = 0;
 
 	m_ServerPresence.m_iPlayerCount = 0; // this should actually be 0 at this point, so shouldn't need updating later
 	m_ServerPresence.m_iMaxPlayers = 0;
@@ -170,12 +169,6 @@ void ServerPresenceManager::SetPort(const int iPort)
 	m_ServerPresence.m_iPort = iPort;
 }
 
-void ServerPresenceManager::SetAuthPort(const int iAuthPort)
-{
-	// update authport
-	m_ServerPresence.m_iAuthPort = iAuthPort;
-}
-
 void ServerPresenceManager::SetName(const std::string sServerNameUnicode)
 {
 	// update name
diff --git a/NorthstarDLL/server/serverpresence.h b/NorthstarDLL/server/serverpresence.h
index 3df2b68d..3aabecde 100644
--- a/NorthstarDLL/server/serverpresence.h
+++ b/NorthstarDLL/server/serverpresence.h
@@ -5,7 +5,6 @@ struct ServerPresence
 {
   public:
 	int m_iPort;
-	int m_iAuthPort;
 
 	std::string m_sServerId;
 
@@ -28,7 +27,6 @@ struct ServerPresence
 	ServerPresence(const ServerPresence* obj)
 	{
 		m_iPort = obj->m_iPort;
-		m_iAuthPort = obj->m_iAuthPort;
 
 		m_sServerId = obj->m_sServerId;
 
@@ -83,7 +81,6 @@ class ServerPresenceManager
 	void RunFrame(double flCurrentTime);
 
 	void SetPort(const int iPort);
-	void SetAuthPort(const int iPort);
 
 	void SetName(const std::string sServerNameUnicode);
 	void SetDescription(const std::string sServerDescUnicode);