4 files changed, 762 insertions, 0 deletions
diff --git a/NorthstarDLL/server/auth/bansystem.cpp b/NorthstarDLL/server/auth/bansystem.cpp
new file mode 100644
index 00000000..56719ed9
--- /dev/null
+++ b/NorthstarDLL/server/auth/bansystem.cpp
@@ -0,0 +1,222 @@
+#pragma once
+#include "pch.h"
+#include "bansystem.h"
+#include "serverauthentication.h"
+#include "shared/maxplayers.h"
+#include "core/convar/concommand.h"
+#include "server/r2server.h"
+#include "engine/r2engine.h"
+#include "config/profile.h"
+
+#include <filesystem>
+
+const char* BANLIST_PATH_SUFFIX = "/banlist.txt";
+const char BANLIST_COMMENT_CHAR = '#';
+
+ServerBanSystem* g_pBanSystem;
+
+void ServerBanSystem::OpenBanlist()
+{
+	std::ifstream banlistStream(GetNorthstarPrefix() + "/banlist.txt");
+
+	if (!banlistStream.fail())
+	{
+		std::string line;
+		while (std::getline(banlistStream, line))
+		{
+			// ignore line if first char is # or line is empty
+			if (line == "" || line.front() == BANLIST_COMMENT_CHAR)
+				continue;
+
+			// remove tabs which shouldnt be there but maybe someone did the funny
+			line.erase(std::remove(line.begin(), line.end(), '\t'), line.end());
+			// remove spaces to allow for spaces before uids
+			line.erase(std::remove(line.begin(), line.end(), ' '), line.end());
+
+			// check if line is empty to allow for newlines in the file
+			if (line == "")
+				continue;
+
+			// for inline comments like: 123123123 #banned for unfunny
+			std::string uid = line.substr(0, line.find(BANLIST_COMMENT_CHAR));
+
+			m_vBannedUids.push_back(strtoull(uid.c_str(), nullptr, 10));
+		}
+
+		banlistStream.close();
+	}
+
+	// open write stream for banlist // dont do this to allow for all time access
+	// m_sBanlistStream.open(GetNorthstarPrefix() + "/banlist.txt", std::ofstream::out | std::ofstream::binary | std::ofstream::app);
+}
+
+void ServerBanSystem::ReloadBanlist()
+{
+	std::ifstream fsBanlist(GetNorthstarPrefix() + "/banlist.txt");
+
+	if (!fsBanlist.fail())
+	{
+		std::string line;
+		// since we wanna use this as the reload func we need to clear the list
+		m_vBannedUids.clear();
+		while (std::getline(fsBanlist, line))
+			m_vBannedUids.push_back(strtoull(line.c_str(), nullptr, 10));
+
+		fsBanlist.close();
+	}
+}
+
+void ServerBanSystem::ClearBanlist()
+{
+	m_vBannedUids.clear();
+
+	// reopen the file, don't provide std::ofstream::app so it clears on open
+	m_sBanlistStream.close();
+	m_sBanlistStream.open(GetNorthstarPrefix() + "/banlist.txt", std::ofstream::out | std::ofstream::binary);
+	m_sBanlistStream.close();
+}
+
+void ServerBanSystem::BanUID(uint64_t uid)
+{
+	// checking if last char is \n to make sure uids arent getting fucked
+	std::ifstream fsBanlist(GetNorthstarPrefix() + "/banlist.txt");
+	std::string content((std::istreambuf_iterator<char>(fsBanlist)), (std::istreambuf_iterator<char>()));
+	fsBanlist.close();
+
+	m_sBanlistStream.open(GetNorthstarPrefix() + "/banlist.txt", std::ofstream::out | std::ofstream::binary | std::ofstream::app);
+	if (content.back() != '\n')
+		m_sBanlistStream << std::endl;
+
+	m_vBannedUids.push_back(uid);
+	m_sBanlistStream << std::to_string(uid) << std::endl;
+	m_sBanlistStream.close();
+	spdlog::info("{} was banned", uid);
+}
+
+void ServerBanSystem::UnbanUID(uint64_t uid)
+{
+	auto findResult = std::find(m_vBannedUids.begin(), m_vBannedUids.end(), uid);
+	if (findResult == m_vBannedUids.end())
+		return;
+
+	m_vBannedUids.erase(findResult);
+
+	std::vector<std::string> banlistText;
+	std::ifstream fs_readBanlist(GetNorthstarPrefix() + "/banlist.txt");
+
+	if (!fs_readBanlist.fail())
+	{
+		std::string line;
+		while (std::getline(fs_readBanlist, line))
+		{
+			// support for comments and newlines added in https://github.com/R2Northstar/NorthstarLauncher/pull/227
+
+			std::string modLine = line; // copy the line into a free var that we can fuck with, line will be the original
+
+			// remove tabs which shouldnt be there but maybe someone did the funny
+			modLine.erase(std::remove(modLine.begin(), modLine.end(), '\t'), modLine.end());
+			// remove spaces to allow for spaces before uids
+			modLine.erase(std::remove(modLine.begin(), modLine.end(), ' '), modLine.end());
+
+			// ignore line if first char is # or empty line, just add it
+			if (line.front() == BANLIST_COMMENT_CHAR || modLine == "")
+			{
+				banlistText.push_back(line);
+				continue;
+			}
+
+			// for inline comments like: 123123123 #banned for unfunny
+			std::string lineUid = line.substr(0, line.find(BANLIST_COMMENT_CHAR));
+			// have to erase spaces or else inline comments will fuck up the uid finding
+			lineUid.erase(std::remove(lineUid.begin(), lineUid.end(), '\t'), lineUid.end());
+			lineUid.erase(std::remove(lineUid.begin(), lineUid.end(), ' '), lineUid.end());
+
+			// if the uid in the line is the uid we wanna unban
+			if (std::to_string(uid) == lineUid)
+			{
+				// comment the uid out
+				line.insert(0, "# ");
+
+				// add a comment with unban date
+				// not necessary but i feel like this makes it better
+				std::time_t t = std::time(0);
+				std::tm* now = std::localtime(&t);
+
+				std::ostringstream unbanComment;
+
+				//{y}/{m}/{d} {h}:{m}
+				unbanComment << " # unban date: ";
+				unbanComment << now->tm_year + 1900 << "-"; // this lib is so fucking awful
+				unbanComment << std::setw(2) << std::setfill('0') << now->tm_mon + 1 << "-";
+				unbanComment << std::setw(2) << std::setfill('0') << now->tm_mday << " ";
+				unbanComment << std::setw(2) << std::setfill('0') << now->tm_hour << ":";
+				unbanComment << std::setw(2) << std::setfill('0') << now->tm_min;
+
+				line.append(unbanComment.str());
+			}
+
+			banlistText.push_back(line);
+		}
+
+		fs_readBanlist.close();
+	}
+
+	// open write stream for banlist // without append so we clear the file
+	if (m_sBanlistStream.is_open())
+		m_sBanlistStream.close();
+	m_sBanlistStream.open(GetNorthstarPrefix() + "/banlist.txt", std::ofstream::out | std::ofstream::binary);
+
+	for (std::string updatedLine : banlistText)
+		m_sBanlistStream << updatedLine << std::endl;
+
+	m_sBanlistStream.close();
+	spdlog::info("{} was unbanned", uid);
+}
+
+bool ServerBanSystem::IsUIDAllowed(uint64_t uid)
+{
+	ReloadBanlist(); // Reload to have up to date list on join
+	return std::find(m_vBannedUids.begin(), m_vBannedUids.end(), uid) == m_vBannedUids.end();
+}
+
+void ConCommand_ban(const CCommand& args)
+{
+	if (args.ArgC() < 2)
+		return;
+
+	for (int i = 0; i < R2::GetMaxPlayers(); i++)
+	{
+		R2::CBaseClient* player = &R2::g_pClientArray[i];
+
+		if (!strcmp(player->m_Name, args.Arg(1)) || !strcmp(player->m_UID, args.Arg(1)))
+		{
+			g_pBanSystem->BanUID(strtoull(player->m_UID, nullptr, 10));
+			R2::CBaseClient__Disconnect(player, 1, "Banned from server");
+			break;
+		}
+	}
+}
+
+void ConCommand_unban(const CCommand& args)
+{
+	if (args.ArgC() < 2)
+		return;
+
+	// assumedly the player being unbanned here wasn't already connected, so don't need to iterate over players or anything
+	g_pBanSystem->UnbanUID(strtoull(args.Arg(1), nullptr, 10));
+}
+
+void ConCommand_clearbanlist(const CCommand& args)
+{
+	g_pBanSystem->ClearBanlist();
+}
+
+ON_DLL_LOAD_RELIESON("engine.dll", BanSystem, ConCommand, (CModule module))
+{
+	g_pBanSystem = new ServerBanSystem;
+	g_pBanSystem->OpenBanlist();
+
+	RegisterConCommand("ban", ConCommand_ban, "bans a given player by uid or name", FCVAR_GAMEDLL);
+	RegisterConCommand("unban", ConCommand_unban, "unbans a given player by uid", FCVAR_GAMEDLL);
+	RegisterConCommand("clearbanlist", ConCommand_clearbanlist, "clears all uids on the banlist", FCVAR_GAMEDLL);
+}
diff --git a/NorthstarDLL/server/auth/bansystem.h b/NorthstarDLL/server/auth/bansystem.h
new file mode 100644
index 00000000..6f180126
--- /dev/null
+++ b/NorthstarDLL/server/auth/bansystem.h
@@ -0,0 +1,19 @@
+#pragma once
+#include <fstream>
+
+class ServerBanSystem
+{
+  private:
+	std::ofstream m_sBanlistStream;
+	std::vector<uint64_t> m_vBannedUids;
+
+  public:
+	void OpenBanlist();
+	void ReloadBanlist();
+	void ClearBanlist();
+	void BanUID(uint64_t uid);
+	void UnbanUID(uint64_t uid);
+	bool IsUIDAllowed(uint64_t uid);
+};
+
+extern ServerBanSystem* g_pBanSystem;
diff --git a/NorthstarDLL/server/auth/serverauthentication.cpp b/NorthstarDLL/server/auth/serverauthentication.cpp
new file mode 100644
index 00000000..ac1d5f17
--- /dev/null
+++ b/NorthstarDLL/server/auth/serverauthentication.cpp
@@ -0,0 +1,462 @@
+#include "pch.h"
+#include "serverauthentication.h"
+#include "shared/exploit_fixes/ns_limits.h"
+#include "core/convar/cvar.h"
+#include "core/convar/convar.h"
+#include "masterserver/masterserver.h"
+#include "server/serverpresence.h"
+#include "engine/hoststate.h"
+#include "shared/maxplayers.h"
+#include "bansystem.h"
+#include "core/convar/concommand.h"
+#include "dedicated/dedicated.h"
+#include "config/profile.h"
+#include "core/tier0.h"
+#include "engine/r2engine.h"
+#include "client/r2client.h"
+#include "server/r2server.h"
+
+#include "httplib.h"
+
+#include <fstream>
+#include <filesystem>
+#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()
+{
+	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;
+					}
+
+					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();
+}
+
+void ServerAuthenticationManager::StopPlayerAuthServer()
+{
+	if (!m_bRunningPlayerAuthThread)
+	{
+		spdlog::warn("ServerAuthenticationManager::StopPlayerAuthServer was called while m_bRunningPlayerAuthThread is false");
+		return;
+	}
+
+	m_bRunningPlayerAuthThread = false;
+	m_PlayerAuthServer.stop();
+}
+
+void ServerAuthenticationManager::AddPlayer(R2::CBaseClient* player, const char* pToken)
+{
+	PlayerAuthenticationData additionalData;
+	additionalData.pdataSize = m_RemoteAuthenticationData[pToken].pdataSize;
+	additionalData.usingLocalPdata = player->m_iPersistenceReady == R2::ePersistenceReady::READY_INSECURE;
+
+	m_PlayerAuthenticationData.insert(std::make_pair(player, additionalData));
+}
+
+void ServerAuthenticationManager::RemovePlayer(R2::CBaseClient* player)
+{
+	if (m_PlayerAuthenticationData.count(player))
+		m_PlayerAuthenticationData.erase(player);
+}
+
+bool checkIsPlayerNameValid(const char* name)
+{
+	int len = strlen(name);
+	// Restricts name to max 63 characters
+	if (len >= 64)
+		return false;
+	for (int i = 0; i < len; i++)
+	{
+		// Restricts the characters in the name to a restricted range in ASCII
+		if (static_cast<int>(name[i]) < 32 || static_cast<int>(name[i]) > 126)
+		{
+			return false;
+		}
+	}
+	return true;
+}
+
+bool ServerAuthenticationManager::VerifyPlayerName(const char* authToken, const char* name)
+{
+	std::lock_guard<std::mutex> guard(m_AuthDataMutex);
+
+	if (CVar_ns_auth_allow_insecure->GetInt())
+	{
+		spdlog::info("Allowing player with name '{}' because ns_auth_allow_insecure is enabled", name);
+		return true;
+	}
+
+	if (!checkIsPlayerNameValid(name))
+	{
+		spdlog::info("Rejecting player with name '{}' because the name contains forbidden characters", name);
+		return false;
+	}
+	// TODO: We should really have a better way of doing this for singleplayer
+	// Best way of doing this would be to check if server is actually in singleplayer mode, or just running a SP map in multiplayer
+	// Currently there's not an easy way of checking this, so we just disable this check if mapname starts with `sp_`
+	// This means that player names are not checked on singleplayer
+	if ((m_RemoteAuthenticationData.empty() || m_RemoteAuthenticationData.count(std::string(authToken)) == 0) &&
+		strncmp(R2::g_pHostState->m_levelName, "sp_", 3) != 0)
+	{
+		spdlog::info("Rejecting player with name '{}' because authToken '{}' was not found", name, authToken);
+		return false;
+	}
+
+	const RemoteAuthData& authData = m_RemoteAuthenticationData[authToken];
+
+	if (*authData.username && strncmp(name, authData.username, 64) != 0)
+	{
+		spdlog::info("Rejecting player with name '{}' because name does not match expected name '{}'", name, authData.username);
+		return false;
+	}
+
+	return true;
+}
+
+bool ServerAuthenticationManager::CheckDuplicateAccounts(R2::CBaseClient* player)
+{
+	if (m_bAllowDuplicateAccounts)
+		return true;
+
+	bool bHasUidPlayer = false;
+	for (int i = 0; i < R2::GetMaxPlayers(); i++)
+		if (&R2::g_pClientArray[i] != player && !strcmp(R2::g_pClientArray[i].m_UID, player->m_UID))
+			return false;
+
+	return true;
+}
+
+bool ServerAuthenticationManager::AuthenticatePlayer(R2::CBaseClient* player, uint64_t uid, char* authToken)
+{
+	std::string strUid = std::to_string(uid);
+	std::lock_guard<std::mutex> guard(m_AuthDataMutex);
+
+	if (!strncmp(R2::g_pHostState->m_levelName, "sp_", 3))
+		return true;
+
+	// copy uuid
+	strcpy(player->m_UID, strUid.c_str());
+
+	bool authFail = true;
+	if (!m_RemoteAuthenticationData.empty() && m_RemoteAuthenticationData.count(std::string(authToken)))
+	{
+		if (!CheckDuplicateAccounts(player))
+			return false;
+
+		// use stored auth data
+		RemoteAuthData authData = m_RemoteAuthenticationData[authToken];
+
+		if (!strcmp(strUid.c_str(), authData.uid)) // connecting client's uid is the same as auth's uid
+		{
+			// if we're resetting let script handle the reset
+			if (!m_bForceResetLocalPlayerPersistence || strcmp(authData.uid, R2::g_pLocalPlayerUserID))
+			{
+				// copy pdata into buffer
+				memcpy(player->m_PersistenceBuffer, authData.pdata, authData.pdataSize);
+			}
+
+			// set persistent data as ready
+			player->m_iPersistenceReady = R2::ePersistenceReady::READY_REMOTE;
+			authFail = false;
+		}
+	}
+
+	if (authFail)
+	{
+		if (CVar_ns_auth_allow_insecure->GetBool())
+		{
+			// set persistent data as ready
+			// note: actual placeholder persistent data is populated in script with InitPersistentData()
+			player->m_iPersistenceReady = R2::ePersistenceReady::READY_INSECURE;
+			return true;
+		}
+		else
+			return false;
+	}
+
+	return true; // auth successful, client stays on
+}
+
+bool ServerAuthenticationManager::RemovePlayerAuthData(R2::CBaseClient* player)
+{
+	if (!Cvar_ns_erase_auth_info->GetBool()) // keep auth data forever
+		return false;
+
+	// hack for special case where we're on a local server, so we erase our own newly created auth data on disconnect
+	if (m_bNeedLocalAuthForNewgame && !strcmp(player->m_UID, R2::g_pLocalPlayerUserID))
+		return false;
+
+	// we don't have our auth token at this point, so lookup authdata by uid
+	for (auto& auth : m_RemoteAuthenticationData)
+	{
+		if (!strcmp(player->m_UID, auth.second.uid))
+		{
+			// pretty sure this is fine, since we don't iterate after the erase
+			// i think if we iterated after it'd be undefined behaviour tho
+			std::lock_guard<std::mutex> guard(m_AuthDataMutex);
+
+			delete[] auth.second.pdata;
+			m_RemoteAuthenticationData.erase(auth.first);
+			return true;
+		}
+	}
+
+	return false;
+}
+
+void ServerAuthenticationManager::WritePersistentData(R2::CBaseClient* player)
+{
+	if (player->m_iPersistenceReady == R2::ePersistenceReady::READY_REMOTE)
+	{
+		g_pMasterServerManager->WritePlayerPersistentData(
+			player->m_UID, (const char*)player->m_PersistenceBuffer, m_PlayerAuthenticationData[player].pdataSize);
+	}
+	else if (CVar_ns_auth_allow_insecure_write->GetBool())
+	{
+		// todo: write pdata to disk here
+	}
+}
+
+// auth hooks
+
+// store these in vars so we can use them in CBaseClient::Connect
+// this is fine because ptrs won't decay by the time we use this, just don't use it outside of calls from cbaseclient::connectclient
+char* pNextPlayerToken;
+uint64_t iNextPlayerUid;
+
+// clang-format off
+AUTOHOOK(CBaseServer__ConnectClient, engine.dll + 0x114430,
+void*,, (
+	void* self,
+	void* addr,
+	void* a3,
+	uint32_t a4,
+	uint32_t a5,
+	int32_t a6,
+	void* a7,
+	char* playerName,
+	char* serverFilter,
+	void* a10,
+	char a11,
+	void* a12,
+	char a13,
+	char a14,
+	int64_t uid,
+	uint32_t a16,
+	uint32_t a17))
+// clang-format on
+{
+	// auth tokens are sent with serverfilter, can't be accessed from player struct to my knowledge, so have to do this here
+	pNextPlayerToken = serverFilter;
+	iNextPlayerUid = uid;
+
+	spdlog::info(
+		"CBaseServer__ClientConnect attempted connection with uid {}, playerName '{}', serverFilter '{}'", uid, playerName, serverFilter);
+
+	if (!g_pServerAuthentication->VerifyPlayerName(pNextPlayerToken, playerName))
+	{
+		CBaseServer__RejectConnection(self, *((int*)self + 3), addr, "Invalid Name.\n");
+		return nullptr;
+	}
+	if (!g_pBanSystem->IsUIDAllowed(uid))
+	{
+		CBaseServer__RejectConnection(self, *((int*)self + 3), addr, "Banned From server.\n");
+		return nullptr;
+	}
+
+	return CBaseServer__ConnectClient(self, addr, a3, a4, a5, a6, a7, playerName, serverFilter, a10, a11, a12, a13, a14, uid, a16, a17);
+}
+
+// clang-format off
+AUTOHOOK(CBaseClient__Connect, engine.dll + 0x101740,
+bool,, (R2::CBaseClient* self, char* name, void* netchan_ptr_arg, char b_fake_player_arg, void* a5, char* Buffer, void* a7))
+// clang-format on
+{
+	// try to auth player, dc if it fails
+	// we connect regardless of auth, because returning bad from this function can fuck client state p bad
+	bool ret = CBaseClient__Connect(self, name, netchan_ptr_arg, b_fake_player_arg, a5, Buffer, a7);
+	if (!ret)
+		return ret;
+
+	if (!g_pServerAuthentication->VerifyPlayerName(pNextPlayerToken, name))
+	{
+		R2::CBaseClient__Disconnect(self, 1, "Invalid Name.\n");
+		return false;
+	}
+	if (!g_pBanSystem->IsUIDAllowed(iNextPlayerUid))
+	{
+		R2::CBaseClient__Disconnect(self, 1, "Banned From server.\n");
+		return false;
+	}
+	if (!g_pServerAuthentication->AuthenticatePlayer(self, iNextPlayerUid, pNextPlayerToken))
+	{
+		R2::CBaseClient__Disconnect(self, 1, "Authentication Failed.\n");
+		return false;
+	}
+
+	g_pServerAuthentication->AddPlayer(self, pNextPlayerToken);
+	g_pServerLimits->AddPlayer(self);
+
+	return ret;
+}
+
+// clang-format off
+AUTOHOOK(CBaseClient__ActivatePlayer, engine.dll + 0x100F80,
+void,, (R2::CBaseClient* self))
+// clang-format on
+{
+	// if we're authed, write our persistent data
+	// RemovePlayerAuthData returns true if it removed successfully, i.e. on first call only, and we only want to write on >= second call
+	// (since this func is called on map loads)
+	if (self->m_iPersistenceReady >= R2::ePersistenceReady::READY && !g_pServerAuthentication->RemovePlayerAuthData(self))
+	{
+		g_pServerAuthentication->m_bForceResetLocalPlayerPersistence = false;
+		g_pServerAuthentication->WritePersistentData(self);
+		g_pServerPresence->SetPlayerCount(g_pServerAuthentication->m_PlayerAuthenticationData.size());
+	}
+
+	CBaseClient__ActivatePlayer(self);
+}
+
+// clang-format off
+AUTOHOOK(_CBaseClient__Disconnect, engine.dll + 0x1012C0,
+void,, (R2::CBaseClient* self, uint32_t unknownButAlways1, const char* pReason, ...))
+// clang-format on
+{
+	// have to manually format message because can't pass varargs to original func
+	char buf[1024];
+
+	va_list va;
+	va_start(va, pReason);
+	vsprintf(buf, pReason, va);
+	va_end(va);
+
+	// this reason is used while connecting to a local server, hacky, but just ignore it
+	if (strcmp(pReason, "Connection closing"))
+	{
+		spdlog::info("Player {} disconnected: \"{}\"", self->m_Name, buf);
+
+		// dcing, write persistent data
+		if (g_pServerAuthentication->m_PlayerAuthenticationData[self].needPersistenceWriteOnLeave)
+			g_pServerAuthentication->WritePersistentData(self);
+		g_pServerAuthentication->RemovePlayerAuthData(self); // won't do anything 99% of the time, but just in case
+
+		g_pServerAuthentication->RemovePlayer(self);
+		g_pServerLimits->RemovePlayer(self);
+	}
+
+	else if (g_pServerAuthentication->m_RemoteAuthenticationData.count(self->m_Name))
+	{
+		g_pServerAuthentication->RemovePlayer(self);
+		g_pServerLimits->RemovePlayer(self);
+	}
+
+	g_pServerPresence->SetPlayerCount(g_pServerAuthentication->m_PlayerAuthenticationData.size());
+
+	_CBaseClient__Disconnect(self, unknownButAlways1, buf);
+}
+
+void ConCommand_ns_resetpersistence(const CCommand& args)
+{
+	if (*R2::g_pServerState == R2::server_state_t::ss_active)
+	{
+		spdlog::error("ns_resetpersistence must be entered from the main menu");
+		return;
+	}
+
+	spdlog::info("resetting persistence on next lobby load...");
+	g_pServerAuthentication->m_bForceResetLocalPlayerPersistence = true;
+}
+
+ON_DLL_LOAD_RELIESON("engine.dll", ServerAuthentication, (ConCommand, ConVar), (CModule module))
+{
+	AUTOHOOK_DISPATCH()
+
+	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 =
+		new ConVar("ns_auth_allow_insecure", "0", FCVAR_GAMEDLL, "Whether this server will allow unauthenicated players to connect");
+	g_pServerAuthentication->CVar_ns_auth_allow_insecure_write = new ConVar(
+		"ns_auth_allow_insecure_write",
+		"0",
+		FCVAR_GAMEDLL,
+		"Whether the pdata of unauthenticated clients will be written to disk when changed");
+
+	RegisterConCommand(
+		"ns_resetpersistence", ConCommand_ns_resetpersistence, "resets your pdata when you next enter the lobby", FCVAR_NONE);
+
+	// patch to disable kicking based on incorrect serverfilter in connectclient, since we repurpose it for use as an auth token
+	module.Offset(0x114655).Patch("EB");
+
+	// patch to disable fairfight marking players as cheaters and kicking them
+	module.Offset(0x101012).Patch("E9 90 00");
+
+	CBaseServer__RejectConnection = module.Offset(0x1182E0).As<CBaseServer__RejectConnectionType>();
+
+	if (Tier0::CommandLine()->CheckParm("-allowdupeaccounts"))
+	{
+		// patch to allow same of multiple account
+		module.Offset(0x114510).Patch("EB");
+
+		g_pServerAuthentication->m_bAllowDuplicateAccounts = true;
+	}
+}
diff --git a/NorthstarDLL/server/auth/serverauthentication.h b/NorthstarDLL/server/auth/serverauthentication.h
new file mode 100644
index 00000000..4ffbbfd6
--- /dev/null
+++ b/NorthstarDLL/server/auth/serverauthentication.h
@@ -0,0 +1,59 @@
+#pragma once
+#include "core/convar/convar.h"
+#include "httplib.h"
+#include "engine/r2engine.h"
+#include <unordered_map>
+#include <string>
+
+struct RemoteAuthData
+{
+	char uid[33];
+	char username[64];
+
+	// pdata
+	char* pdata;
+	size_t pdataSize;
+};
+
+struct PlayerAuthenticationData
+{
+	bool usingLocalPdata;
+	size_t pdataSize;
+	bool needPersistenceWriteOnLeave = true;
+};
+
+typedef int64_t (*CBaseServer__RejectConnectionType)(void* a1, unsigned int a2, void* a3, const char* a4, ...);
+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;
+
+	std::mutex m_AuthDataMutex;
+	std::unordered_map<std::string, RemoteAuthData> m_RemoteAuthenticationData;
+	std::unordered_map<R2::CBaseClient*, PlayerAuthenticationData> m_PlayerAuthenticationData;
+	bool m_bAllowDuplicateAccounts = false;
+	bool m_bRunningPlayerAuthThread = false;
+	bool m_bNeedLocalAuthForNewgame = false;
+	bool m_bForceResetLocalPlayerPersistence = false;
+
+  public:
+	void StartPlayerAuthServer();
+	void StopPlayerAuthServer();
+	void AddPlayer(R2::CBaseClient* player, const char* pToken);
+	void RemovePlayer(R2::CBaseClient* player);
+	bool CheckDuplicateAccounts(R2::CBaseClient* player);
+	bool AuthenticatePlayer(R2::CBaseClient* player, uint64_t uid, char* authToken);
+	bool VerifyPlayerName(const char* authToken, const char* name);
+	bool RemovePlayerAuthData(R2::CBaseClient* player);
+	void WritePersistentData(R2::CBaseClient* player);
+};
+
+extern ServerAuthenticationManager* g_pServerAuthentication;