#include "pch.h" #include "serverauthentication.h" #include "convar.h" #include "hookutils.h" #include "masterserver.h" #include "httplib.h" #include "gameutils.h" #include <fstream> #include <filesystem> #include <thread> const char* AUTHSERVER_VERIFY_STRING = "I am a northstar server!"; // hook types typedef void*(*CBaseServer__ConnectClientType)(void* server, void* a2, void* a3, uint32_t a4, uint32_t a5, int32_t a6, void* a7, void* a8, char* serverFilter, void* a10, char a11, void* a12, char a13, char a14, int64_t uid, uint32_t a16, uint32_t a17); CBaseServer__ConnectClientType CBaseServer__ConnectClient; typedef char(*CBaseClient__ConnectType)(void* self, char* name, __int64 netchan_ptr_arg, char b_fake_player_arg, __int64 a5, char* Buffer, int a7); CBaseClient__ConnectType CBaseClient__Connect; typedef void(*CBaseClient__ActivatePlayerType)(void* self); CBaseClient__ActivatePlayerType CBaseClient__ActivatePlayer; typedef void(*CBaseClient__DisconnectType)(void* self, uint32_t unknownButAlways1, const char* reason, ...); CBaseClient__DisconnectType CBaseClient__Disconnect; typedef char(*CGameClient__ExecuteStringCommandType)(void* self, uint32_t unknown, const char* pCommandString); CGameClient__ExecuteStringCommandType CGameClient__ExecuteStringCommand; typedef char(*__fastcall CNetChan___ProcessMessagesType)(void* self, void* buf); CNetChan___ProcessMessagesType CNetChan___ProcessMessages; typedef char(*CBaseClient__SendServerInfoType)(void* self); CBaseClient__SendServerInfoType CBaseClient__SendServerInfo; typedef bool(*ProcessConnectionlessPacketType)(void* a1, netpacket_t* packet); ProcessConnectionlessPacketType ProcessConnectionlessPacket; // global vars ServerAuthenticationManager* g_ServerAuthenticationManager; 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; ConVar* CVar_sv_quota_stringcmdspersecond; ConVar* Cvar_net_chan_limit_mode; ConVar* Cvar_net_chan_limit_msec_per_sec; ConVar* Cvar_sv_querylimit_per_sec; void ServerAuthenticationManager::StartPlayerAuthServer() { if (m_runningPlayerAuthThread) { spdlog::warn("ServerAuthenticationManager::StartPlayerAuthServer was called while m_runningPlayerAuthThread is true"); return; } m_runningPlayerAuthThread = 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) { // can't just do request.remote_addr == Cvar_ns_masterserver_hostname->m_pszString because the cvar can be a url, gotta resolve an ip from it for comparisons unsigned long remoteAddr = inet_addr(request.remote_addr.c_str()); char* addrPtr = Cvar_ns_masterserver_hostname->m_pszString; char* typeStart = strstr(addrPtr, "://"); if (typeStart) addrPtr = typeStart + 3; hostent* resolvedRemoteAddr = gethostbyname((const char*)addrPtr); if (!request.has_param("id") || !request.has_param("authToken") || request.body.size() >= 65335 || !resolvedRemoteAddr || ((in_addr**)resolvedRemoteAddr->h_addr_list)[0]->S_un.S_addr != remoteAddr) { response.set_content("{\"success\":false}", "application/json"); return; } AuthData newAuthData; strncpy(newAuthData.uid, request.get_param_value("id").c_str(), sizeof(newAuthData.uid)); newAuthData.uid[sizeof(newAuthData.uid) - 1] = 0; 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_authData.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->m_nValue); }); serverThread.detach(); } void ServerAuthenticationManager::StopPlayerAuthServer() { if (!m_runningPlayerAuthThread) { spdlog::warn("ServerAuthenticationManager::StopPlayerAuthServer was called while m_runningPlayerAuthThread is false"); return; } m_runningPlayerAuthThread = false; m_playerAuthServer.stop(); } bool ServerAuthenticationManager::AuthenticatePlayer(void* player, int64_t uid, char* authToken) { std::string strUid = std::to_string(uid); std::lock_guard<std::mutex> guard(m_authDataMutex); bool authFail = true; if (!m_authData.empty() && m_authData.count(std::string(authToken))) { // use stored auth data AuthData authData = m_authData[authToken]; if (!strcmp(strUid.c_str(), authData.uid)) // connecting client's uid is the same as auth's uid { authFail = false; // uuid strcpy((char*)player + 0xF500, strUid.c_str()); // copy pdata into buffer memcpy((char*)player + 0x4FA, authData.pdata, authData.pdataSize); // set persistent data as ready, we use 0x4 internally to mark the client as using remote persistence *((char*)player + 0x4a0) = (char)0x4; } } if (authFail) { if (!CVar_ns_auth_allow_insecure->m_nValue) // no auth data and insecure connections aren't allowed, so dc the client return false; // insecure connections are allowed, try reading from disk // uuid strcpy((char*)player + 0xF500, strUid.c_str()); // try reading pdata file for player std::string pdataPath = "R2Northstar/playerdata_"; pdataPath += strUid; pdataPath += ".pdata"; std::fstream pdataStream(pdataPath, std::ios_base::in); if (pdataStream.fail()) // file doesn't exist, use placeholder pdataStream = std::fstream("R2Northstar/placeholder_playerdata.pdata"); // get file length pdataStream.seekg(0, pdataStream.end); int length = pdataStream.tellg(); pdataStream.seekg(0, pdataStream.beg); // copy pdata into buffer pdataStream.read((char*)player + 0x4FA, length); pdataStream.close(); // set persistent data as ready, we use 0x3 internally to mark the client as using local persistence *((char*)player + 0x4a0) = (char)0x3; } return true; // auth successful, client stays on } bool ServerAuthenticationManager::RemovePlayerAuthData(void* player) { if (!Cvar_ns_erase_auth_info->m_nValue) 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((char*)player + 0xF500, g_LocalPlayerUserID)) return false; // we don't have our auth token at this point, so lookup authdata by uid for (auto& auth : m_authData) { if (!strcmp((char*)player + 0xF500, 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_authData.erase(auth.first); return true; } } return false; } void ServerAuthenticationManager::WritePersistentData(void* player) { // we use 0x4 internally to mark clients as using remote persistence if (*((char*)player + 0x4A0) == (char)0x4) { g_MasterServerManager->WritePlayerPersistentData((char*)player + 0xF500, (char*)player + 0x4FA, m_additionalPlayerData[player].pdataSize); } else if (CVar_ns_auth_allow_insecure_write->m_nValue) { // 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 cbaseclient::connect char* nextPlayerToken; int64_t nextPlayerUid; void* CBaseServer__ConnectClientHook(void* server, void* a2, void* a3, uint32_t a4, uint32_t a5, int32_t a6, void* a7, void* a8, char* serverFilter, void* a10, char a11, void* a12, char a13, char a14, int64_t uid, uint32_t a16, uint32_t a17) { // auth tokens are sent with serverfilter, can't be accessed from player struct to my knowledge, so have to do this here nextPlayerToken = serverFilter; nextPlayerUid = uid; return CBaseServer__ConnectClient(server, a2, a3, a4, a5, a6, a7, a8, serverFilter, a10, a11, a12, a13, a14, uid, a16, a17); } char CBaseClient__ConnectHook(void* self, char* name, __int64 netchan_ptr_arg, char b_fake_player_arg, __int64 a5, char* Buffer, int a7) { // try to auth player, dc if it fails // we connect irregardless of auth, because returning bad from this function can fuck client state p bad char ret = CBaseClient__Connect(self, name, netchan_ptr_arg, b_fake_player_arg, a5, Buffer, a7); if (strlen(name) >= 64) // fix for name overflow bug CBaseClient__Disconnect(self, 1, "Invalid name"); else if (!g_ServerAuthenticationManager->AuthenticatePlayer(self, nextPlayerUid, nextPlayerToken) && g_MasterServerManager->m_bRequireClientAuth) CBaseClient__Disconnect(self, 1, "Authentication Failed"); if (!g_ServerAuthenticationManager->m_additionalPlayerData.count(self)) { AdditionalPlayerData additionalData; additionalData.pdataSize = g_ServerAuthenticationManager->m_authData[nextPlayerToken].pdataSize; additionalData.usingLocalPdata = *((char*)self + 0x4a0) == (char)0x3; g_ServerAuthenticationManager->m_additionalPlayerData.insert(std::make_pair(self, additionalData)); } return ret; } void CBaseClient__ActivatePlayerHook(void* self) { // 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 (*((char*)self + 0x4A0) >= (char)0x3 && !g_ServerAuthenticationManager->RemovePlayerAuthData(self)) { g_ServerAuthenticationManager->WritePersistentData(self); g_MasterServerManager->UpdateServerPlayerCount(g_ServerAuthenticationManager->m_additionalPlayerData.size()); } CBaseClient__ActivatePlayer(self); } void CBaseClient__DisconnectHook(void* self, uint32_t unknownButAlways1, const char* reason, ...) { // have to manually format message because can't pass varargs to original func char buf[1024]; va_list va; va_start(va, reason); vsprintf(buf, reason, va); va_end(va); // this reason is used while connecting to a local server, hacky, but just ignore it if (strcmp(reason, "Connection closing")) { spdlog::info("Player {} disconnected: \"{}\"", (char*)self + 0x16, buf); // dcing, write persistent data if (g_ServerAuthenticationManager->m_additionalPlayerData[self].needPersistenceWriteOnLeave) g_ServerAuthenticationManager->WritePersistentData(self); g_ServerAuthenticationManager->RemovePlayerAuthData(self); // won't do anything 99% of the time, but just in case } if (g_ServerAuthenticationManager->m_additionalPlayerData.count(self)) { g_ServerAuthenticationManager->m_additionalPlayerData.erase(self); g_MasterServerManager->UpdateServerPlayerCount(g_ServerAuthenticationManager->m_additionalPlayerData.size()); } CBaseClient__Disconnect(self, unknownButAlways1, buf); } // maybe this should be done outside of auth code, but effort to refactor rn and it sorta fits char CGameClient__ExecuteStringCommandHook(void* self, uint32_t unknown, const char* pCommandString) { if (CVar_sv_quota_stringcmdspersecond->m_nValue != -1) { // note: this isn't super perfect, legit clients can trigger it in lobby, mostly good enough tho imo // https://github.com/perilouswithadollarsign/cstrike15_src/blob/f82112a2388b841d72cb62ca48ab1846dfcc11c8/engine/sv_client.cpp#L1513 if (Plat_FloatTime() - g_ServerAuthenticationManager->m_additionalPlayerData[self].lastClientCommandQuotaStart >= 1.0) { // reset quota g_ServerAuthenticationManager->m_additionalPlayerData[self].lastClientCommandQuotaStart = Plat_FloatTime(); g_ServerAuthenticationManager->m_additionalPlayerData[self].numClientCommandsInQuota = 0; } g_ServerAuthenticationManager->m_additionalPlayerData[self].numClientCommandsInQuota++; if (g_ServerAuthenticationManager->m_additionalPlayerData[self].numClientCommandsInQuota > CVar_sv_quota_stringcmdspersecond->m_nValue) { // too many stringcmds, dc player CBaseClient__Disconnect(self, 1, "Sent too many stringcmd commands"); return false; } } // todo later, basically just limit to CVar_sv_quota_stringcmdspersecond->m_nValue stringcmds per client per second return CGameClient__ExecuteStringCommand(self, unknown, pCommandString); } char __fastcall CNetChan___ProcessMessagesHook(void* self, void* buf) { double startTime = Plat_FloatTime(); char ret = CNetChan___ProcessMessages(self, buf); // check processing limit if (Cvar_net_chan_limit_mode->m_nValue != 0) { // player that sent the message void* sender = *(void**)((char*)self + 368); // if no sender, return // relatively certain this is fine? if (!sender || !g_ServerAuthenticationManager->m_additionalPlayerData.count(sender)) return ret; // reset every second if (startTime - g_ServerAuthenticationManager->m_additionalPlayerData[sender].lastNetChanProcessingLimitStart >= 1.0 || g_ServerAuthenticationManager->m_additionalPlayerData[sender].lastNetChanProcessingLimitStart == -1.0) { g_ServerAuthenticationManager->m_additionalPlayerData[sender].lastNetChanProcessingLimitStart = startTime; g_ServerAuthenticationManager->m_additionalPlayerData[sender].netChanProcessingLimitTime = 0.0; } g_ServerAuthenticationManager->m_additionalPlayerData[sender].netChanProcessingLimitTime += (Plat_FloatTime() * 1000) - (startTime * 1000); int32_t limit = Cvar_net_chan_limit_msec_per_sec->m_nValue; if (g_pHostState->m_iCurrentState != HostState_t::HS_RUN) limit *= 2; // give clients more headroom in these states, as alot of clients will tend to time out here if (g_ServerAuthenticationManager->m_additionalPlayerData[sender].netChanProcessingLimitTime >= limit) { spdlog::warn("Client {} hit netchan processing limit with {}ms of processing time this second (max is {})", (char*)sender + 0x16, g_ServerAuthenticationManager->m_additionalPlayerData[sender].netChanProcessingLimitTime, Cvar_net_chan_limit_msec_per_sec->m_nValue); // mode 1 = kick, mode 2 = log without kicking if (Cvar_net_chan_limit_mode->m_nValue == 1) { CBaseClient__Disconnect(sender, 1, "Exceeded net channel processing limit"); return false; } } } return ret; } bool bWasWritingStringTableSuccessful; void CBaseClient__SendServerInfoHook(void* self) { bWasWritingStringTableSuccessful = true; CBaseClient__SendServerInfo(self); if (!bWasWritingStringTableSuccessful) CBaseClient__Disconnect(self, 1, "Overflowed CNetworkStringTableContainer::WriteBaselines, try restarting your client and reconnecting"); } bool ProcessConnectionlessPacketHook(void* a1, netpacket_t* packet) { if (packet->adr.type == NA_IP) { // bad lookup: optimise later tm UnconnectedPlayerSendData* sendData = nullptr; for (UnconnectedPlayerSendData& foundSendData : g_ServerAuthenticationManager->m_unconnectedPlayerSendData) { if (!memcmp(packet->adr.ip, foundSendData.ip, 16)) { sendData = &foundSendData; break; } } if (!sendData) { sendData = &g_ServerAuthenticationManager->m_unconnectedPlayerSendData.emplace_back(); memcpy(sendData->ip, packet->adr.ip, 16); } if (Plat_FloatTime() < sendData->timeoutEnd) return false; if (Plat_FloatTime() - sendData->lastQuotaStart >= 1.0) { sendData->lastQuotaStart = Plat_FloatTime(); sendData->packetCount = 0; } sendData->packetCount++; if (sendData->packetCount >= Cvar_sv_querylimit_per_sec->m_nValue) { spdlog::warn("Client went over connectionless ratelimit of {} per sec with packet of type {}", Cvar_sv_querylimit_per_sec->m_nValue, packet->data[4]); // timeout for a minute sendData->timeoutEnd = Plat_FloatTime() + 60.0; return false; } } return ProcessConnectionlessPacket(a1, packet); } void InitialiseServerAuthentication(HMODULE baseAddress) { g_ServerAuthenticationManager = new ServerAuthenticationManager; Cvar_ns_erase_auth_info = RegisterConVar("ns_erase_auth_info", "1", FCVAR_GAMEDLL, "Whether auth info should be erased from this server on disconnect or crash"); CVar_ns_auth_allow_insecure = RegisterConVar("ns_auth_allow_insecure", "0", FCVAR_GAMEDLL, "Whether this server will allow unauthenicated players to connect"); CVar_ns_auth_allow_insecure_write = RegisterConVar("ns_auth_allow_insecure_write", "0", FCVAR_GAMEDLL, "Whether the pdata of unauthenticated clients will be written to disk when changed"); // literally just stolen from a fix valve used in csgo CVar_sv_quota_stringcmdspersecond = RegisterConVar("sv_quota_stringcmdspersecond", "60", FCVAR_GAMEDLL, "How many string commands per second clients are allowed to submit, 0 to disallow all string commands"); // https://blog.counter-strike.net/index.php/2019/07/24922/ but different because idk how to check what current tick number is Cvar_net_chan_limit_mode = RegisterConVar("net_chan_limit_mode", "0", FCVAR_GAMEDLL, "The mode for netchan processing limits: 0 = none, 1 = kick, 2 = log"); Cvar_net_chan_limit_msec_per_sec = RegisterConVar("net_chan_limit_msec_per_sec", "0", FCVAR_GAMEDLL, "Netchannel processing is limited to so many milliseconds, abort connection if exceeding budget"); Cvar_ns_player_auth_port = RegisterConVar("ns_player_auth_port", "8081", FCVAR_GAMEDLL, ""); Cvar_sv_querylimit_per_sec = RegisterConVar("sv_querylimit_per_sec", "15", FCVAR_GAMEDLL, ""); HookEnabler hook; ENABLER_CREATEHOOK(hook, (char*)baseAddress + 0x114430, &CBaseServer__ConnectClientHook, reinterpret_cast<LPVOID*>(&CBaseServer__ConnectClient)); ENABLER_CREATEHOOK(hook, (char*)baseAddress + 0x101740, &CBaseClient__ConnectHook, reinterpret_cast<LPVOID*>(&CBaseClient__Connect)); ENABLER_CREATEHOOK(hook, (char*)baseAddress + 0x100F80, &CBaseClient__ActivatePlayerHook, reinterpret_cast<LPVOID*>(&CBaseClient__ActivatePlayer)); ENABLER_CREATEHOOK(hook, (char*)baseAddress + 0x1012C0, &CBaseClient__DisconnectHook, reinterpret_cast<LPVOID*>(&CBaseClient__Disconnect)); ENABLER_CREATEHOOK(hook, (char*)baseAddress + 0x1022E0, &CGameClient__ExecuteStringCommandHook, reinterpret_cast<LPVOID*>(&CGameClient__ExecuteStringCommand)); ENABLER_CREATEHOOK(hook, (char*)baseAddress + 0x2140A0, &CNetChan___ProcessMessagesHook, reinterpret_cast<LPVOID*>(&CNetChan___ProcessMessages)); ENABLER_CREATEHOOK(hook, (char*)baseAddress + 0x104FB0, &CBaseClient__SendServerInfoHook, reinterpret_cast<LPVOID*>(&CBaseClient__SendServerInfo)); ENABLER_CREATEHOOK(hook, (char*)baseAddress + 0x117800, &ProcessConnectionlessPacketHook, reinterpret_cast<LPVOID*>(&ProcessConnectionlessPacket)); // patch to disable kicking based on incorrect serverfilter in connectclient, since we repurpose it for use as an auth token { void* ptr = (char*)baseAddress + 0x114655; TempReadWrite rw(ptr); *((char*)ptr) = (char)0xEB; // jz => jmp } // patch to disable fairfight marking players as cheaters and kicking them { void* ptr = (char*)baseAddress + 0x101012; TempReadWrite rw(ptr); *((char*)ptr) = (char)0xE9; // jz => jmp *((char*)ptr + 1) = (char)0x90; *((char*)ptr + 2) = (char)0x0; } // patch to allow same of multiple account { void* ptr = (char*)baseAddress + 0x114510; TempReadWrite rw(ptr); *((char*)ptr) = (char)0xEB; // jz => jmp } // patch to set bWasWritingStringTableSuccessful in CNetworkStringTableContainer::WriteBaselines if it fails { bool* writeAddress = (bool*)(&bWasWritingStringTableSuccessful - ((bool*)baseAddress + 0x234EDC)); void* ptr = (char*)baseAddress + 0x234ED2; TempReadWrite rw(ptr); *((char*)ptr) = (char)0xC7; *((char*)ptr + 1) = (char)0x05; *(int*)((char*)ptr + 2) = (int)writeAddress; *((char*)ptr + 6) = (char)0x00; *((char*)ptr + 7) = (char)0x00; *((char*)ptr + 8) = (char)0x00; *((char*)ptr + 9) = (char)0x00; *((char*)ptr + 10) = (char)0x90; *((char*)ptr + 11) = (char)0x90; *((char*)ptr + 12) = (char)0x90; *((char*)ptr + 13) = (char)0x90; *((char*)ptr + 14) = (char)0x90; } }