diff options
Diffstat (limited to 'NorthstarDLL/ExploitFixes.cpp')
| -rw-r--r-- | NorthstarDLL/ExploitFixes.cpp | 553 |
1 files changed, 0 insertions, 553 deletions
diff --git a/NorthstarDLL/ExploitFixes.cpp b/NorthstarDLL/ExploitFixes.cpp deleted file mode 100644 index 31fa349a..00000000 --- a/NorthstarDLL/ExploitFixes.cpp +++ /dev/null @@ -1,553 +0,0 @@ -#include "pch.h" - -#include "ExploitFixes.h" -#include "ExploitFixes_UTF8Parser.h" -#include "NSMem.h" -#include "cvar.h" -#include "gameutils.h" - -ConVar* ns_exploitfixes_log; -#define SHOULD_LOG (ns_exploitfixes_log->m_Value.m_nValue > 0) -#define BLOCKED_INFO(s) \ - ( \ - [=]() -> bool \ - { \ - if (SHOULD_LOG) \ - { \ - std::stringstream stream; \ - stream << "ExploitFixes.cpp: " << BLOCK_PREFIX << s; \ - spdlog::error(stream.str()); \ - } \ - return false; \ - }()) - -struct Float3 -{ - float vals[3]; - - void MakeValid() - { - for (auto& val : vals) - if (isnan(val)) - val = 0; - } -}; - -#define BLOCK_NETMSG_FUNC(name, pattern) \ - KHOOK(name, ("engine.dll", pattern), bool, __fastcall, (void* thisptr, void* buffer)) \ - { \ - return false; \ - } - -// Servers can literally request a screenshot from any client, yeah no -BLOCK_NETMSG_FUNC(CLC_Screenshot_WriteToBuffer, "48 89 5C 24 ? 57 48 83 EC 20 8B 42 10"); -BLOCK_NETMSG_FUNC(CLC_Screenshot_ReadFromBuffer, "48 89 5C 24 ? 48 89 6C 24 ? 48 89 74 24 ? 57 48 83 EC 20 48 8B DA 48 8B 52 38"); - -// This is unused ingame and a big exploit vector -BLOCK_NETMSG_FUNC(Base_CmdKeyValues_ReadFromBuffer, "40 55 48 81 EC ? ? ? ? 48 8D 6C 24 ? 48 89 5D 70"); - -KHOOK(CClient_ProcessSetConVar, ("engine.dll", "48 8B D1 48 8B 49 18 48 8B 01 48 FF 60 10"), bool, __fastcall, (void* pMsg)) -{ - - constexpr int ENTRY_STR_LEN = 260; - struct SetConVarEntry - { - char name[ENTRY_STR_LEN]; - char val[ENTRY_STR_LEN]; - }; - - struct NET_SetConVar - { - void* vtable; - void* unk1; - void* unk2; - void* m_pMessageHandler; - SetConVarEntry* m_ConVars; // convar entry array - void* unk5; // these 2 unks are just vector capacity or whatever - void* unk6; - int m_ConVars_count; // amount of cvar entries in array (this will not be out of bounds) - }; - - auto msg = (NET_SetConVar*)pMsg; - - bool areWeServer; - - { - // Figure out of we are the client or the server - // To do this, we utilize the msg's m_pMessageHandler pointer - // m_pMessageHandler points to a virtual class that handles all net messages - // The first virtual table function of our m_pMessageHandler will differ if it is IServerMessageHandler or IClientMessageHandler - void* msgHandlerVTableFirstFunc = **(void****)(msg->m_pMessageHandler); - static auto engineBaseAddress = (uintptr_t)GetModuleHandleA("engine.dll"); - auto offset = uintptr_t(msgHandlerVTableFirstFunc) - engineBaseAddress; - - constexpr uintptr_t CLIENTSTATE_FIRST_VFUNC_OFFSET = 0x8A15C; - areWeServer = offset != CLIENTSTATE_FIRST_VFUNC_OFFSET; - } - - std::string BLOCK_PREFIX = std::string {"NET_SetConVar ("} + (areWeServer ? "server" : "client") + "): Blocked dangerous/invalid msg: "; - - if (areWeServer) - { - constexpr int SETCONVAR_SANITY_AMOUNT_LIMIT = 69; - if (msg->m_ConVars_count < 1 || msg->m_ConVars_count > SETCONVAR_SANITY_AMOUNT_LIMIT) - { - return BLOCKED_INFO("Invalid m_ConVars_count (" << msg->m_ConVars_count << ")"); - } - } - - for (int i = 0; i < msg->m_ConVars_count; i++) - { - auto entry = msg->m_ConVars + i; - - // Safety check for memory access - if (NSMem::IsMemoryReadable(entry, sizeof(*entry))) - { - - // Find null terminators - bool nameValid = false, valValid = false; - for (int i = 0; i < ENTRY_STR_LEN; i++) - { - if (!entry->name[i]) - nameValid = true; - if (!entry->val[i]) - valValid = true; - } - - if (!nameValid || !valValid) - return BLOCKED_INFO("Missing null terminators"); - - auto realVar = g_pCVar->FindVar(entry->name); - - if (realVar) - memcpy( - entry->name, - realVar->m_ConCommandBase.m_pszName, - strlen(realVar->m_ConCommandBase.m_pszName) + 1); // Force name to match case - - bool isValidFlags = true; - if (areWeServer) - { - if (realVar) - isValidFlags = ConVar::IsFlagSet(realVar, FCVAR_USERINFO); // ConVar MUST be userinfo var - } - else - { - // TODO: Should probably have some sanity checks, but can't find any that are consistent - } - - if (!isValidFlags) - { - if (!realVar) - { - return BLOCKED_INFO("Invalid flags on nonexistant cvar (how tho???)"); - } - else - { - return BLOCKED_INFO( - "Invalid flags (" << std::hex << "0x" << realVar->m_ConCommandBase.m_nFlags << "), var is " << entry->name); - } - } - } - else - { - return BLOCKED_INFO("Unreadable memory at " << (void*)entry); // Not risking that one, they all gotta be readable - } - } - - return oCClient_ProcessSetConVar(msg); -} - -// Purpose: prevent invalid user CMDs -KHOOK(CClient_ProcessUsercmds, ("engine.dll", "40 55 56 48 83 EC 58"), bool, __fastcall, (void* thisptr, void* pMsg)) -{ - struct CLC_Move - { - BYTE gap0[24]; - void* m_pMessageHandler; - int m_nBackupCommands; - int m_nNewCommands; - int m_nLength; - // bf_read m_DataIn; - // bf_write m_DataOut; - }; - - auto msg = (CLC_Move*)pMsg; - - const char* BLOCK_PREFIX = "ProcessUserCmds: "; - - if (msg->m_nBackupCommands < 0) - { - return BLOCKED_INFO("Invalid m_nBackupCommands (" << msg->m_nBackupCommands << ")"); - } - - if (msg->m_nNewCommands < 0) - { - return BLOCKED_INFO("Invalid m_nNewCommands (" << msg->m_nNewCommands << ")"); - } - - constexpr int NUMCMD_SANITY_LIMIT = 16; - if ((msg->m_nNewCommands + msg->m_nBackupCommands) > NUMCMD_SANITY_LIMIT) - { - return BLOCKED_INFO("Command count is too high (new: " << msg->m_nNewCommands << ", backup: " << msg->m_nBackupCommands << ")"); - } - - if (msg->m_nLength <= 0) - return BLOCKED_INFO("Invalid message length (" << msg->m_nLength << ")"); - - return oCClient_ProcessUsercmds(thisptr, pMsg); -} - -KHOOK(ReadUsercmd, ("server.dll", "4C 89 44 24 ? 53 55 56 57"), void, __fastcall, (void* buf, void* pCmd_move, void* pCmd_from)) -{ - // Let normal usercmd read happen first, it's safe - oReadUsercmd(buf, pCmd_move, pCmd_from); - - // Now let's make sure the CMD we read isnt messed up to prevent numerous exploits (including server crashing) - struct alignas(4) SV_CUserCmd - { - DWORD command_number; - DWORD tick_count; - float command_time; - Float3 worldViewAngles; - BYTE gap18[4]; - Float3 localViewAngles; - Float3 attackangles; - Float3 move; - DWORD buttons; - BYTE impulse; - short weaponselect; - DWORD meleetarget; - BYTE gap4C[24]; - char headoffset; - BYTE gap65[11]; - Float3 cameraPos; - Float3 cameraAngles; - BYTE gap88[4]; - int tickSomething; - DWORD dword90; - DWORD predictedServerEventAck; - DWORD dword98; - float frameTime; - }; - - auto cmd = (SV_CUserCmd*)pCmd_move; - auto fromCmd = (SV_CUserCmd*)pCmd_from; - - std::string BLOCK_PREFIX = - "ReadUsercmd (command_number delta: " + std::to_string(cmd->command_number - fromCmd->command_number) + "): "; - - // Fix invalid player angles - cmd->worldViewAngles.MakeValid(); - cmd->attackangles.MakeValid(); - cmd->localViewAngles.MakeValid(); - - // Fix invalid camera angles - cmd->cameraPos.MakeValid(); - cmd->cameraAngles.MakeValid(); - - // Fix invaid movement vector - cmd->move.MakeValid(); - - if (cmd->tick_count == 0 || cmd->command_time <= 0) - { - BLOCKED_INFO( - "Bogus cmd timing (tick_count: " << cmd->tick_count << ", frameTime: " << cmd->frameTime - << ", commandTime : " << cmd->command_time << ")"); - goto INVALID_CMD; // No simulation of bogus-timed cmds - } - - return; - -INVALID_CMD: - // Fix any gameplay-affecting cmd properties - // NOTE: Currently tickcount/frametime is set to 0, this ~shouldn't~ cause any problems - cmd->worldViewAngles = cmd->localViewAngles = cmd->attackangles = cmd->cameraAngles = {0, 0, 0}; - cmd->tick_count = cmd->frameTime = 0; - cmd->move = cmd->cameraPos = {0, 0, 0}; - cmd->buttons = 0; - cmd->meleetarget = 0; -} - -// basically: by default r2 isn't set as a valve mod, meaning that m_bRestrictServerCommands is false -// this is HORRIBLE for security, because it means servers can run arbitrary concommands on clients -// especially since we have script commands this could theoretically be awful -KHOOK(IsValveMod, ("engine.dll", "48 83 EC 28 48 8B 0D ? ? ? ? 48 8D 15 ? ? ? ? E8 ? ? ? ? 85 C0 74 63"), bool, __fastcall, ()) -{ - bool result = !CommandLine()->CheckParm("-norestrictservercommands"); - spdlog::info("ExploitFixes: Overriding IsValveMod to {}...", result); - return result; -} - -// Fix respawn's crappy UTF8 parser so it doesn't crash -_- -// This also means you can launch multiplayer with "communities_enabled 1" and not crash, you're welcome -KHOOK( - CrashFunc_ParseUTF8, - ("engine.dll", "48 89 5C 24 ? 48 89 6C 24 ? 48 89 74 24 ? 57 41 54 41 55 41 56 41 57 48 83 EC 20 8B 1A"), - bool, - __fastcall, - (INT64 * a1, DWORD* a2, char* strData)) -{ - - static void* targetRetAddr = NSMem::PatternScan("engine.dll", "84 C0 75 2C 49 8B 16"); - -#ifdef _MSC_VER - if (_ReturnAddress() == targetRetAddr) -#else - if (__builtin_return_address(0) == targetRetAddr) -#endif - { - if (!ExploitFixes_UTF8Parser::CheckValid(a1, a2, strData)) - { - const char* BLOCK_PREFIX = "ParseUTF8 Hook: "; - BLOCKED_INFO("Ignoring potentially-crashing utf8 string"); - return false; - } - } - - return oCrashFunc_ParseUTF8(a1, a2, strData); -} - -// GetEntByIndex (called by ScriptGetEntByIndex) doesn't check for the index being out of bounds when it's -// above the max entity count. This allows it to be used to crash servers. -typedef void*(__fastcall* GetEntByIndexType)(int idx); -GetEntByIndexType GetEntByIndex; - -static void* GetEntByIndexHook(int idx) -{ - if (idx >= 0x4000) - { - spdlog::info("GetEntByIndex {} is out of bounds", idx); - return nullptr; - } - return GetEntByIndex(idx); -} - -// RELOCATED FROM https://github.com/R2Northstar/NorthstarLauncher/commit/25dbf729cfc75107a0fcf0186924b58ecc05214b -// Rewrite of CLZSS::SafeUncompress to fix a vulnerability where malicious compressed payloads could cause the decompressor to try to read -// out of the bounds of the output buffer. -KHOOK( - LZSS_SafeUncompress, - ("engine.dll", "48 89 5C 24 ? 48 89 6C 24 ? 48 89 74 24 ? 48 89 7C 24 ? 33 ED 41 8B F9"), - uint32_t, - __fastcall, - (void* self, const unsigned char* pInput, unsigned char* pOutput, unsigned int unBufSize)) -{ - static constexpr int LZSS_LOOKSHIFT = 4; - - uint32_t totalBytes = 0; - int getCmdByte = 0, cmdByte = 0; - - struct lzss_header_t - { - uint32_t id, actualSize; - }; - - lzss_header_t header = *(lzss_header_t*)pInput; - - if (pInput == NULL || header.id != 'SSZL' || header.actualSize == 0 || header.actualSize > unBufSize) - return 0; - - pInput += sizeof(lzss_header_t); - - for (;;) - { - if (!getCmdByte) - cmdByte = *pInput++; - - getCmdByte = (getCmdByte + 1) & 0x07; - - if (cmdByte & 0x01) - { - int position = *pInput++ << LZSS_LOOKSHIFT; - position |= (*pInput >> LZSS_LOOKSHIFT); - position += 1; - - int count = (*pInput++ & 0x0F) + 1; - if (count == 1) - break; - - // Ensure reference chunk exists entirely within our buffer - if (position > totalBytes) - return 0; - - totalBytes += count; - if (totalBytes > unBufSize) - return 0; - - unsigned char* pSource = pOutput - position; - for (int i = 0; i < count; i++) - *pOutput++ = *pSource++; - } - else - { - totalBytes++; - if (totalBytes > unBufSize) - return 0; - - *pOutput++ = *pInput++; - } - cmdByte = cmdByte >> 1; - } - - if (totalBytes == header.actualSize) - { - return totalBytes; - } - else - { - return 0; - } -} - -////////////////////////////////////////////////// - -void DoBytePatches() -{ - uintptr_t engineBase = (uintptr_t)GetModuleHandleA("engine.dll"); - uintptr_t serverBase = (uintptr_t)GetModuleHandleA("server.dll"); - - // patches to make commands run from client/ui script still work - // note: this is likely preventable in a nicer way? test prolly - NSMem::BytePatch(engineBase + 0x4FB65, "EB 11"); - NSMem::BytePatch(engineBase + 0x4FBAC, "EB 16"); - - // disconnect concommand - { - uintptr_t addr = engineBase + 0x5ADA2D; - int val = *(int*)addr | FCVAR_SERVER_CAN_EXECUTE; - NSMem::BytePatch(addr, (BYTE*)&val, sizeof(int)); - } - - { // Dumb ANTITAMPER patches (they negatively impact performance and security) - - constexpr const char* ANTITAMPER_EXPORTS[] = { - "ANTITAMPER_SPOTCHECK_CODEMARKER", - "ANTITAMPER_TESTVALUE_CODEMARKER", - "ANTITAMPER_TRIGGER_CODEMARKER", - }; - - // Prevent thesefrom actually doing anything - for (auto exportName : ANTITAMPER_EXPORTS) - { - - auto address = (uintptr_t)GetProcAddress(GetModuleHandleA("server.dll"), exportName); - if (!address) - { - spdlog::warn("Failed to find AntiTamper function export \"{}\"", exportName); - } - else - { - // Just return, none of them have any args or are userpurge - NSMem::BytePatch(address, "C3"); - - spdlog::info("Patched AntiTamper function export \"{}\"", exportName); - } - } - } -} - -KHOOK( - SpecialClientCommand, - ("server.dll", "48 89 5C 24 ? 48 89 74 24 ? 55 57 41 56 48 8D 6C 24 ? 48 81 EC ? ? ? ? 83 3A 00"), - bool, - __fastcall, - (void* player, CCommand* command)) -{ - - static ConVar* sv_cheats = g_pCVar->FindVar("sv_cheats"); - - if (sv_cheats->GetBool()) - return oSpecialClientCommand(player, command); // Don't block anything if sv_cheats is on - - // These are mostly from Portal 2 (sigh) - constexpr const char* blockedCommands[] = { - "emit", // Sound-playing exploit (likely for Portal 2 coop devs testing splitscreen sound or something) - - // These both execute a command for every single entity for some reason, nice one valve - "pre_go_to_hub", - "pre_go_to_calibration", - - "end_movie", // Calls "__MovieFinished" script function, not sure exactly what this does but it certainly isn't needed - "load_recent_checkpoint" // This is the instant-respawn exploit, literally just calls RespawnPlayer() - }; - - if (command->ArgC() > 0) - { - std::string cmdStr = command->Arg(0); - for (char& c : cmdStr) - c = tolower(c); - - for (const char* blockedCommand : blockedCommands) - { - if (cmdStr.find(blockedCommand) != std::string::npos) - { - // Block this command - spdlog::warn("Blocked exploititive client command \"{}\".", cmdStr); - return true; - } - } - } - - return oSpecialClientCommand(player, command); -} - -void SetupKHook(KHook* hook) -{ - if (hook->Setup()) - { - spdlog::debug("KHook::Setup(): Hooked at {}", hook->targetFuncAddr); - } - else - { - spdlog::critical("\tFAILED to initialize all exploit patches."); - - // Force exit - MessageBoxA(0, "FAILED to initialize all exploit patches.", "Northstar", MB_ICONERROR); - exit(0); - } -} - -void ExploitFixes::LoadCallback_MultiModule(HMODULE baseAddress) -{ - - spdlog::info("ExploitFixes::LoadCallback_MultiModule({}) ...", (void*)baseAddress); - - int hooksEnabled = 0; - for (auto itr = KHook::_allHooks.begin(); itr != KHook::_allHooks.end(); itr++) - { - auto curHook = *itr; - if (GetModuleHandleA(curHook->targetFunc.moduleName) == baseAddress) - { - SetupKHook(curHook); - itr = KHook::_allHooks.erase(itr); // Prevent repeated initialization - - hooksEnabled++; - - if (itr == KHook::_allHooks.end()) - break; - } - } - - spdlog::info("\tEnabled {} hooks.", hooksEnabled); -} - -void ExploitFixes::LoadCallback_Full(HMODULE baseAddress) -{ - spdlog::info("ExploitFixes::LoadCallback_Full ..."); - - spdlog::info("\tByte patching..."); - DoBytePatches(); - - for (KHook* hook : KHook::_allHooks) - SetupKHook(hook); - - spdlog::info("\tInitialized " + std::to_string(KHook::_allHooks.size()) + " late exploit-patch hooks."); - KHook::_allHooks.clear(); - - ns_exploitfixes_log = - new ConVar("ns_exploitfixes_log", "1", FCVAR_GAMEDLL, "Whether to log whenever ExploitFixes.cpp blocks/corrects something"); - - HookEnabler hook; - ENABLER_CREATEHOOK(hook, (char*)baseAddress + 0x2a8a50, &GetEntByIndexHook, reinterpret_cast<LPVOID*>(&GetEntByIndex)); -} |