diff options
Diffstat (limited to 'NorthstarDLL/exploitfixes.cpp')
| -rw-r--r-- | NorthstarDLL/exploitfixes.cpp | 458 |
1 files changed, 0 insertions, 458 deletions
diff --git a/NorthstarDLL/exploitfixes.cpp b/NorthstarDLL/exploitfixes.cpp deleted file mode 100644 index 240c352c..00000000 --- a/NorthstarDLL/exploitfixes.cpp +++ /dev/null @@ -1,458 +0,0 @@ -#include "pch.h" -#include "cvar.h" -#include "limits.h" -#include "dedicated.h" -#include "tier0.h" -#include "r2engine.h" -#include "r2client.h" -#include "vector.h" - -AUTOHOOK_INIT() - -ConVar* Cvar_ns_exploitfixes_log; -ConVar* Cvar_ns_should_log_all_clientcommands; - -ConVar* Cvar_sv_cheats; - -#define BLOCKED_INFO(s) \ - ( \ - [=]() -> bool \ - { \ - if (Cvar_ns_exploitfixes_log->GetBool()) \ - { \ - std::stringstream stream; \ - stream << "ExploitFixes.cpp: " << BLOCK_PREFIX << s; \ - spdlog::error(stream.str()); \ - } \ - return false; \ - }()) - -// block bad netmessages -// Servers can literally request a screenshot from any client, yeah no -// clang-format off -AUTOHOOK(CLC_Screenshot_WriteToBuffer, engine.dll + 0x22AF20, -bool, __fastcall, (void* thisptr, void* buffer)) // 48 89 5C 24 ? 57 48 83 EC 20 8B 42 10 -// clang-format on -{ - return false; -} - -// clang-format off -AUTOHOOK(CLC_Screenshot_ReadFromBuffer, engine.dll + 0x221F00, -bool, __fastcall, (void* thisptr, void* buffer)) // 48 89 5C 24 ? 48 89 6C 24 ? 48 89 74 24 ? 57 48 83 EC 20 48 8B DA 48 8B 52 38 -// clang-format on -{ - return false; -} - -// This is unused ingame and a big client=>server=>client exploit vector -// clang-format off -AUTOHOOK(Base_CmdKeyValues_ReadFromBuffer, engine.dll + 0x220040, -bool, __fastcall, (void* thisptr, void* buffer)) // 40 55 48 81 EC ? ? ? ? 48 8D 6C 24 ? 48 89 5D 70 -// clang-format on -{ - return false; -} - -// clang-format off -AUTOHOOK(CClient_ProcessSetConVar, engine.dll + 0x75CF0, -bool, __fastcall, (void* pMsg)) // 48 8B D1 48 8B 49 18 48 8B 01 48 FF 60 10 -// clang-format on -{ - - 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 bIsServerFrame = Tier0::ThreadInServerFrameThread(); - - std::string BLOCK_PREFIX = - std::string {"NET_SetConVar ("} + (bIsServerFrame ? "server" : "client") + "): Blocked dangerous/invalid msg: "; - - if (bIsServerFrame) - { - 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 (MemoryAddress(entry).IsMemoryReadable(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"); - - ConVar* pVar = R2::g_pCVar->FindVar(entry->name); - - if (pVar) - { - memcpy( - entry->name, - pVar->m_ConCommandBase.m_pszName, - strlen(pVar->m_ConCommandBase.m_pszName) + 1); // Force name to match case - - int iFlags = bIsServerFrame ? FCVAR_USERINFO : FCVAR_REPLICATED; - if (!pVar->IsFlagSet(iFlags)) - return BLOCKED_INFO( - "Invalid flags (" << std::hex << "0x" << pVar->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 CClient_ProcessSetConVar(msg); -} - -// prevent invalid user CMDs -// clang-format off -AUTOHOOK(CClient_ProcessUsercmds, engine.dll + 0x1040F0, -bool, __fastcall, (void* thisptr, void* pMsg)) // 40 55 56 48 83 EC 58 -// clang-format on -{ - 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 << ")"); - } - - if (msg->m_nLength <= 0) - return BLOCKED_INFO("Invalid message length (" << msg->m_nLength << ")"); - - return CClient_ProcessUsercmds(thisptr, pMsg); -} - -// clang-format off -AUTOHOOK(ReadUsercmd, server.dll + 0x2603F0, -void, __fastcall, (void* buf, void* pCmd_move, void* pCmd_from)) // 4C 89 44 24 ? 53 55 56 57 -// clang-format on -{ - // Let normal usercmd read happen first, it's safe - ReadUsercmd(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; - Vector3 worldViewAngles; - BYTE gap18[4]; - Vector3 localViewAngles; - Vector3 attackangles; - Vector3 move; - DWORD buttons; - BYTE impulse; - short weaponselect; - DWORD meleetarget; - BYTE gap4C[24]; - char headoffset; - BYTE gap65[11]; - Vector3 cameraPos; - Vector3 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->frameTime <= 0 || 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; -} - -// ensure that GetLocalBaseClient().m_bRestrictServerCommands is set correctly, which the return value of this function controls -// this is IsValveMod in source, but we're making it IsRespawnMod now since valve didn't make this one -// clang-format off -AUTOHOOK(IsRespawnMod, engine.dll + 0x1C6360, -bool, __fastcall, (const char* pModName)) // 48 83 EC 28 48 8B 0D ? ? ? ? 48 8D 15 ? ? ? ? E8 ? ? ? ? 85 C0 74 63 -// clang-format on -{ - // somewhat temp, store the modname here, since we don't have a proper ptr in engine to it rn - int iSize = strlen(pModName); - R2::g_pModName = new char[iSize + 1]; - strcpy(R2::g_pModName, pModName); - - return (!strcmp("r2", pModName) || !strcmp("r1", pModName)) && !Tier0::CommandLine()->CheckParm("-norestrictservercommands"); -} - -// ratelimit stringcmds, and prevent remote clients from calling commands that they shouldn't -bool (*CCommand__Tokenize)(CCommand& self, const char* pCommandString, R2::cmd_source_t commandSource); - -// clang-format off -AUTOHOOK(CGameClient__ExecuteStringCommand, engine.dll + 0x1022E0, -bool, __fastcall, (R2::CBaseClient* self, uint32_t unknown, const char* pCommandString)) -// clang-format on -{ - if (Cvar_ns_should_log_all_clientcommands->GetBool()) - spdlog::info("player {} (UID: {}) sent command: \"{}\"", self->m_Name, self->m_UID, pCommandString); - - if (!g_pServerLimits->CheckStringCommandLimits(self)) - { - R2::CBaseClient__Disconnect(self, 1, "Sent too many stringcmd commands"); - return false; - } - - // verify the command we're trying to execute is FCVAR_GAMEDLL_FOR_REMOTE_CLIENTS, if it's a concommand - char* commandBuf[1040]; // assumedly this is the size of CCommand since we don't have an actual constructor - memset(commandBuf, 0, sizeof(commandBuf)); - CCommand tempCommand = *(CCommand*)&commandBuf; - - if (!CCommand__Tokenize(tempCommand, pCommandString, R2::cmd_source_t::kCommandSrcCode) || !tempCommand.ArgC()) - return false; - - ConCommand* command = R2::g_pCVar->FindCommand(tempCommand.Arg(0)); - - // if the command doesn't exist pass it on to ExecuteStringCommand for script clientcommands and stuff - if (command && !command->IsFlagSet(FCVAR_GAMEDLL_FOR_REMOTE_CLIENTS)) - { - // ensure FCVAR_GAMEDLL concommands without FCVAR_GAMEDLL_FOR_REMOTE_CLIENTS can't be executed by remote clients - if (IsDedicatedServer()) - return false; - - if (strcmp(self->m_UID, R2::g_pLocalPlayerUserID)) - return false; - } - - // check for and block abusable legacy portal 2 commands - // these aren't actually concommands weirdly enough, they seem to just be hardcoded - if (!Cvar_sv_cheats->GetBool()) - { - 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() - }; - - int iCmdLength = strlen(tempCommand.Arg(0)); - - bool bIsBadCommand = false; - for (auto& blockedCommand : blockedCommands) - { - if (iCmdLength != strlen(blockedCommand)) - continue; - - for (int i = 0; tempCommand.Arg(0)[i]; i++) - if (tolower(tempCommand.Arg(0)[i]) != blockedCommand[i]) - goto NEXT_COMMAND; // break out of this loop, then go to next command - - // this is a command we need to block - return false; - NEXT_COMMAND:; - } - } - - return CGameClient__ExecuteStringCommand(self, unknown, pCommandString); -} - -// prevent clients from crashing servers through overflowing CNetworkStringTableContainer::WriteBaselines -bool bWasWritingStringTableSuccessful; - -// clang-format off -AUTOHOOK(CBaseClient__SendServerInfo, engine.dll + 0x104FB0, -void, __fastcall, (void* self)) -// clang-format on -{ - bWasWritingStringTableSuccessful = true; - CBaseClient__SendServerInfo(self); - if (!bWasWritingStringTableSuccessful) - R2::CBaseClient__Disconnect( - self, 1, "Overflowed CNetworkStringTableContainer::WriteBaselines, try restarting your client and reconnecting"); -} - -// return null when GetEntByIndex is passed an index >= 0x4000 -// this is called from exactly 1 script clientcommand that can be given an arbitrary index, and going above 0x4000 crashes -// clang-format off -AUTOHOOK(GetEntByIndex, server.dll + 0x2A8A50, -void*, __fastcall, (int i)) -// clang-format on -{ - const int MAX_ENT_IDX = 0x4000; - - if (i >= MAX_ENT_IDX) - { - spdlog::warn("GetEntByIndex {} is out of bounds (max {})", i, MAX_ENT_IDX); - return nullptr; - } - - return GetEntByIndex(i); -} -// clang-format off -AUTOHOOK(CL_CopyExistingEntity, engine.dll + 0x6F940, -bool, __fastcall, (void* a1)) -// clang-format on -{ - struct CEntityReadInfo - { - BYTE gap[40]; - int nNewEntity; - }; - - CEntityReadInfo* pReadInfo = (CEntityReadInfo*)a1; - if (pReadInfo->nNewEntity >= 0x1000 || pReadInfo->nNewEntity < 0) - { - // Value isn't sanitized in release builds for - // every game powered by the Source Engine 1 - // causing read/write outside of array bounds. - // This defect has let to the achievement of a - // full-chain RCE exploit. We hook and perform - // sanity checks for the value of m_nNewEntity - // here to prevent this behavior from happening. - return false; - } - - return CL_CopyExistingEntity(a1); -} - -ON_DLL_LOAD("engine.dll", EngineExploitFixes, (CModule module)) -{ - AUTOHOOK_DISPATCH_MODULE(engine.dll) - - CCommand__Tokenize = module.Offset(0x418380).As<bool (*)(CCommand&, const char*, R2::cmd_source_t)>(); - - // allow client/ui to run clientcommands despite restricting servercommands - module.Offset(0x4FB65).Patch("EB 11"); - module.Offset(0x4FBAC).Patch("EB 16"); - - // patch to set bWasWritingStringTableSuccessful in CNetworkStringTableContainer::WriteBaselines if it fails - { - MemoryAddress writeAddress(&bWasWritingStringTableSuccessful - module.Offset(0x234EDC).m_nAddress); - - MemoryAddress addr = module.Offset(0x234ED2); - addr.Patch("C7 05"); - addr.Offset(2).Patch((BYTE*)&writeAddress, sizeof(writeAddress)); - - addr.Offset(6).Patch("00 00 00 00"); - - addr.Offset(10).NOP(5); - } -} - -ON_DLL_LOAD_RELIESON("server.dll", ServerExploitFixes, ConVar, (CModule module)) -{ - AUTOHOOK_DISPATCH_MODULE(server.dll) - - // ret at the start of CServerGameClients::ClientCommandKeyValues as it has no benefit and is forwarded to client (i.e. security issue) - // this prevents the attack vector of client=>server=>client, however server=>client also has clientside patches - module.Offset(0x153920).Patch("C3"); - - // Dumb ANTITAMPER patches (they negatively impact performance and security) - constexpr const char* ANTITAMPER_EXPORTS[] = { - "ANTITAMPER_SPOTCHECK_CODEMARKER", - "ANTITAMPER_TESTVALUE_CODEMARKER", - "ANTITAMPER_TRIGGER_CODEMARKER", - }; - - // Prevent these from actually doing anything - for (auto exportName : ANTITAMPER_EXPORTS) - { - MemoryAddress exportAddr = module.GetExport(exportName); - if (exportAddr) - { - // Just return, none of them have any args or are userpurge - exportAddr.Patch("C3"); - spdlog::info("Patched AntiTamper function export \"{}\"", exportName); - } - } - - Cvar_ns_exploitfixes_log = - new ConVar("ns_exploitfixes_log", "1", FCVAR_GAMEDLL, "Whether to log whenever ExploitFixes.cpp blocks/corrects something"); - Cvar_ns_should_log_all_clientcommands = - new ConVar("ns_should_log_all_clientcommands", "0", FCVAR_NONE, "Whether to log all clientcommands"); - - Cvar_sv_cheats = R2::g_pCVar->FindVar("sv_cheats"); -} |