Restructuring (#365)

* Remove launcher proxy

* Restructuring

* More restructuring

* Fix include dirs

* Fix merge

* Remove clang thing

* Filters

* Oops

5 files changed, 1086 insertions, 0 deletions

diff --git a/NorthstarDLL/shared/exploit_fixes/exploitfixes.cpp b/NorthstarDLL/shared/exploit_fixes/exploitfixes.cpp
new file mode 100644
index 00000000..e4430fd4
--- /dev/null
+++ b/NorthstarDLL/shared/exploit_fixes/exploitfixes.cpp
@@ -0,0 +1,458 @@
+#include "pch.h"
+#include "core/convar/cvar.h"
+#include "ns_limits.h"
+#include "dedicated/dedicated.h"
+#include "core/tier0.h"
+#include "engine/r2engine.h"
+#include "client/r2client.h"
+#include "core/math/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");
+}
diff --git a/NorthstarDLL/shared/exploit_fixes/exploitfixes_lzss.cpp b/NorthstarDLL/shared/exploit_fixes/exploitfixes_lzss.cpp
new file mode 100644
index 00000000..4205133a
--- /dev/null
+++ b/NorthstarDLL/shared/exploit_fixes/exploitfixes_lzss.cpp
@@ -0,0 +1,79 @@
+#include "pch.h"
+
+AUTOHOOK_INIT()
+
+static constexpr int LZSS_LOOKSHIFT = 4;
+
+struct lzss_header_t
+{
+	unsigned int id;
+	unsigned int actualSize;
+};
+
+// 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.
+// clang-format off
+AUTOHOOK(CLZSS__SafeDecompress, engine.dll + 0x432A10,
+unsigned int, __fastcall, (void* self, const unsigned char* pInput, unsigned char* pOutput, unsigned int unBufSize))
+// clang-format on
+{
+	unsigned int totalBytes = 0;
+	int getCmdByte = 0;
+	int cmdByte = 0;
+
+	lzss_header_t header = *(lzss_header_t*)pInput;
+
+	if (!pInput || !header.actualSize || header.id != 0x53535A4C || 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 0;
+
+	return totalBytes;
+}
+
+ON_DLL_LOAD("engine.dll", ExploitFixes_LZSS, (CModule module))
+{
+	AUTOHOOK_DISPATCH()
+}
diff --git a/NorthstarDLL/shared/exploit_fixes/exploitfixes_utf8parser.cpp b/NorthstarDLL/shared/exploit_fixes/exploitfixes_utf8parser.cpp
new file mode 100644
index 00000000..e2510765
--- /dev/null
+++ b/NorthstarDLL/shared/exploit_fixes/exploitfixes_utf8parser.cpp
@@ -0,0 +1,200 @@
+#include "pch.h"
+
+AUTOHOOK_INIT()
+
+INT64(__fastcall* sub_F1320)(DWORD a1, char* a2);
+
+// Reimplementation of an exploitable UTF decoding function in titanfall
+bool __fastcall CheckUTF8Valid(INT64* a1, DWORD* a2, char* strData)
+{
+	DWORD v3; // eax
+	char* v4; // rbx
+	char v5; // si
+	char* _strData; // rdi
+	char* v7; // rbp
+	char v11; // al
+	DWORD v12; // er9
+	DWORD v13; // ecx
+	DWORD v14; // edx
+	DWORD v15; // er8
+	int v16; // eax
+	DWORD v17; // er9
+	int v18; // eax
+	DWORD v19; // er9
+	DWORD v20; // ecx
+	int v21; // eax
+	int v22; // er9
+	DWORD v23; // edx
+	int v24; // eax
+	int v25; // er9
+	DWORD v26; // er9
+	DWORD v27; // er10
+	DWORD v28; // ecx
+	DWORD v29; // edx
+	DWORD v30; // er8
+	int v31; // eax
+	DWORD v32; // er10
+	int v33; // eax
+	DWORD v34; // er10
+	DWORD v35; // ecx
+	int v36; // eax
+	int v37; // er10
+	DWORD v38; // edx
+	int v39; // eax
+	int v40; // er10
+	DWORD v41; // er10
+	INT64 v43; // r8
+	INT64 v44; // rdx
+	INT64 v45; // rcx
+	INT64 v46; // rax
+	INT64 v47; // rax
+	char v48; // al
+	INT64 v49; // r8
+	INT64 v50; // rdx
+	INT64 v51; // rcx
+	INT64 v52; // rax
+	INT64 v53; // rax
+
+	v3 = a2[2];
+	v4 = (char*)(a1[1] + *a2);
+	v5 = 0;
+	_strData = strData;
+	v7 = &v4[*((UINT16*)a2 + 2)];
+	if (v3 >= 2)
+	{
+		++v4;
+		--v7;
+		if (v3 != 2)
+		{
+			while (1)
+			{
+				if (!MemoryAddress(v4).IsMemoryReadable(1))
+					return false; // INVALID
+
+				v11 = *v4++; // crash potential
+				if (v11 != 92)
+					goto LABEL_6;
+				v11 = *v4++;
+				if (v11 == 110)
+					break;
+				switch (v11)
+				{
+				case 't':
+					v11 = 9;
+					goto LABEL_6;
+				case 'r':
+					v11 = 13;
+					goto LABEL_6;
+				case 'b':
+					v11 = 8;
+					goto LABEL_6;
+				case 'f':
+					v11 = 12;
+					goto LABEL_6;
+				}
+				if (v11 != 117)
+					goto LABEL_6;
+				v12 = *v4 | 0x20;
+				v13 = v4[1] | 0x20;
+				v14 = v4[2] | 0x20;
+				v15 = v4[3] | 0x20;
+				v16 = 87;
+				if (v12 <= 0x39)
+					v16 = 48;
+				v17 = v12 - v16;
+				v18 = 87;
+				v19 = v17 << 12;
+				if (v13 <= 0x39)
+					v18 = 48;
+				v20 = v13 - v18;
+				v21 = 87;
+				v22 = (v20 << 8) | v19;
+				if (v14 <= 0x39)
+					v21 = 48;
+				v23 = v14 - v21;
+				v24 = 87;
+				v25 = (16 * v23) | v22;
+				if (v15 <= 0x39)
+					v24 = 48;
+				v4 += 4;
+				v26 = (v15 - v24) | v25;
+				if (v26 - 55296 <= 0x7FF)
+				{
+					if (v26 >= 0xDC00)
+						return true;
+					if (*v4 != 92 || v4[1] != 117)
+						return true;
+
+					v27 = v4[2] | 0x20;
+					v28 = v4[3] | 0x20;
+					v29 = v4[4] | 0x20;
+					v30 = v4[5] | 0x20;
+					v31 = 87;
+					if (v27 <= 0x39)
+						v31 = 48;
+					v32 = v27 - v31;
+					v33 = 87;
+					v34 = v32 << 12;
+					if (v28 <= 0x39)
+						v33 = 48;
+					v35 = v28 - v33;
+					v36 = 87;
+					v37 = (v35 << 8) | v34;
+					if (v29 <= 0x39)
+						v36 = 48;
+					v38 = v29 - v36;
+					v39 = 87;
+					v40 = (16 * v38) | v37;
+					if (v30 <= 0x39)
+						v39 = 48;
+					v4 += 6;
+					v41 = ((v30 - v39) | v40) - 56320;
+					if (v41 > 0x3FF)
+						return true;
+					v26 = v41 | ((v26 - 55296) << 10);
+				}
+				_strData += (DWORD)sub_F1320(v26, _strData);
+			LABEL_7:
+				if (v4 == v7)
+					goto LABEL_48;
+			}
+			v11 = 10;
+		LABEL_6:
+			v5 |= v11;
+			*_strData++ = v11;
+			goto LABEL_7;
+		}
+	}
+LABEL_48:
+	return true;
+}
+
+// prevent utf8 parser from crashing when provided bad data, which can be sent through user-controlled openinvites
+// clang-format off
+AUTOHOOK(Rson_ParseUTF8, engine.dll + 0xEF670, 
+bool, __fastcall, (INT64* a1, DWORD* a2, char* strData)) // 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
+// clang-format on
+{
+	static void* targetRetAddr = CModule("engine.dll").FindPattern("84 C0 75 2C 49 8B 16");
+
+	// only call if we're parsing utf8 data from the network (i.e. communities), otherwise we get perf issues
+	void* pReturnAddress =
+#ifdef _MSC_VER
+		_ReturnAddress()
+#else
+		__builtin_return_address(0)
+#endif
+		;
+
+	if (pReturnAddress == targetRetAddr && !CheckUTF8Valid(a1, a2, strData))
+		return false;
+
+	return Rson_ParseUTF8(a1, a2, strData);
+}
+
+ON_DLL_LOAD("engine.dll", EngineExploitFixes_UTF8Parser, (CModule module))
+{
+	AUTOHOOK_DISPATCH()
+
+	sub_F1320 = module.FindPattern("83 F9 7F 77 08 88 0A").As<INT64(__fastcall*)(DWORD, char*)>();
+}
diff --git a/NorthstarDLL/shared/exploit_fixes/ns_limits.cpp b/NorthstarDLL/shared/exploit_fixes/ns_limits.cpp
new file mode 100644
index 00000000..49f80bab
--- /dev/null
+++ b/NorthstarDLL/shared/exploit_fixes/ns_limits.cpp
@@ -0,0 +1,298 @@
+#include "pch.h"
+#include "ns_limits.h"
+#include "engine/hoststate.h"
+#include "client/r2client.h"
+#include "engine/r2engine.h"
+#include "server/r2server.h"
+#include "shared/maxplayers.h"
+#include "core/tier0.h"
+#include "core/math/vector.h"
+#include "server/auth/serverauthentication.h"
+
+AUTOHOOK_INIT()
+
+ServerLimitsManager* g_pServerLimits;
+
+// todo: make this work on higher timescales, also possibly disable when sv_cheats is set
+void ServerLimitsManager::RunFrame(double flCurrentTime, float flFrameTime)
+{
+	if (Cvar_sv_antispeedhack_enable->GetBool())
+	{
+		// for each player, set their usercmd processing budget for the frame to the last frametime for the server
+		for (int i = 0; i < R2::GetMaxPlayers(); i++)
+		{
+			R2::CBaseClient* player = &R2::g_pClientArray[i];
+
+			if (m_PlayerLimitData.find(player) != m_PlayerLimitData.end())
+			{
+				PlayerLimitData* pLimitData = &g_pServerLimits->m_PlayerLimitData[player];
+				if (pLimitData->flFrameUserCmdBudget < 0.016666667 * Cvar_sv_antispeedhack_maxtickbudget->GetFloat())
+					pLimitData->flFrameUserCmdBudget +=
+						fmax(flFrameTime, 0.016666667) * g_pServerLimits->Cvar_sv_antispeedhack_budgetincreasemultiplier->GetFloat();
+			}
+		}
+	}
+}
+
+void ServerLimitsManager::AddPlayer(R2::CBaseClient* player)
+{
+	PlayerLimitData limitData;
+	limitData.flFrameUserCmdBudget = 0.016666667 * Cvar_sv_antispeedhack_maxtickbudget->GetFloat();
+
+	m_PlayerLimitData.insert(std::make_pair(player, limitData));
+}
+
+void ServerLimitsManager::RemovePlayer(R2::CBaseClient* player)
+{
+	if (m_PlayerLimitData.find(player) != m_PlayerLimitData.end())
+		m_PlayerLimitData.erase(player);
+}
+
+bool ServerLimitsManager::CheckStringCommandLimits(R2::CBaseClient* player)
+{
+	if (CVar_sv_quota_stringcmdspersecond->GetInt() != -1)
+	{
+		// note: this isn't super perfect, legit clients can trigger it in lobby if they try, mostly good enough tho imo
+		if (Tier0::Plat_FloatTime() - m_PlayerLimitData[player].lastClientCommandQuotaStart >= 1.0)
+		{
+			// reset quota
+			m_PlayerLimitData[player].lastClientCommandQuotaStart = Tier0::Plat_FloatTime();
+			m_PlayerLimitData[player].numClientCommandsInQuota = 0;
+		}
+
+		m_PlayerLimitData[player].numClientCommandsInQuota++;
+		if (m_PlayerLimitData[player].numClientCommandsInQuota > CVar_sv_quota_stringcmdspersecond->GetInt())
+		{
+			// too many stringcmds, dc player
+			return false;
+		}
+	}
+
+	return true;
+}
+
+bool ServerLimitsManager::CheckChatLimits(R2::CBaseClient* player)
+{
+	if (Tier0::Plat_FloatTime() - m_PlayerLimitData[player].lastSayTextLimitStart >= 1.0)
+	{
+		m_PlayerLimitData[player].lastSayTextLimitStart = Tier0::Plat_FloatTime();
+		m_PlayerLimitData[player].sayTextLimitCount = 0;
+	}
+
+	if (m_PlayerLimitData[player].sayTextLimitCount >= Cvar_sv_max_chat_messages_per_sec->GetInt())
+		return false;
+
+	m_PlayerLimitData[player].sayTextLimitCount++;
+	return true;
+}
+
+// clang-format off
+AUTOHOOK(CNetChan__ProcessMessages, engine.dll + 0x2140A0, 
+char, __fastcall, (void* self, void* buf))
+// clang-format on
+{
+	enum eNetChanLimitMode
+	{
+		NETCHANLIMIT_WARN,
+		NETCHANLIMIT_KICK
+	};
+
+	double startTime = Tier0::Plat_FloatTime();
+	char ret = CNetChan__ProcessMessages(self, buf);
+
+	// check processing limits, unless we're in a level transition
+	if (R2::g_pHostState->m_iCurrentState == R2::HostState_t::HS_RUN && Tier0::ThreadInServerFrameThread())
+	{
+		// player that sent the message
+		R2::CBaseClient* sender = *(R2::CBaseClient**)((char*)self + 368);
+
+		// if no sender, return
+		// relatively certain this is fine?
+		if (!sender || !g_pServerLimits->m_PlayerLimitData.count(sender))
+			return ret;
+
+		// reset every second
+		if (startTime - g_pServerLimits->m_PlayerLimitData[sender].lastNetChanProcessingLimitStart >= 1.0 ||
+			g_pServerLimits->m_PlayerLimitData[sender].lastNetChanProcessingLimitStart == -1.0)
+		{
+			g_pServerLimits->m_PlayerLimitData[sender].lastNetChanProcessingLimitStart = startTime;
+			g_pServerLimits->m_PlayerLimitData[sender].netChanProcessingLimitTime = 0.0;
+		}
+		g_pServerLimits->m_PlayerLimitData[sender].netChanProcessingLimitTime += (Tier0::Plat_FloatTime() * 1000) - (startTime * 1000);
+
+		if (g_pServerLimits->m_PlayerLimitData[sender].netChanProcessingLimitTime >=
+			g_pServerLimits->Cvar_net_chan_limit_msec_per_sec->GetInt())
+		{
+			spdlog::warn(
+				"Client {} hit netchan processing limit with {}ms of processing time this second (max is {})",
+				(char*)sender + 0x16,
+				g_pServerLimits->m_PlayerLimitData[sender].netChanProcessingLimitTime,
+				g_pServerLimits->Cvar_net_chan_limit_msec_per_sec->GetInt());
+
+			// never kick local player
+			if (g_pServerLimits->Cvar_net_chan_limit_mode->GetInt() != NETCHANLIMIT_WARN && strcmp(R2::g_pLocalPlayerUserID, sender->m_UID))
+			{
+				R2::CBaseClient__Disconnect(sender, 1, "Exceeded net channel processing limit");
+				return false;
+			}
+		}
+	}
+
+	return ret;
+}
+
+// clang-format off
+AUTOHOOK(ProcessConnectionlessPacket, engine.dll + 0x117800, 
+bool, , (void* a1, R2::netpacket_t* packet))
+// clang-format on
+{
+	static const ConVar* Cvar_net_data_block_enabled = R2::g_pCVar->FindVar("net_data_block_enabled");
+
+	// don't ratelimit datablock packets as long as datablock is enabled
+	if (packet->adr.type == R2::NA_IP &&
+		(!(packet->data[4] == 'N' && Cvar_net_data_block_enabled->GetBool()) || !Cvar_net_data_block_enabled->GetBool()))
+	{
+		// bad lookup: optimise later tm
+		UnconnectedPlayerLimitData* sendData = nullptr;
+		for (UnconnectedPlayerLimitData& foundSendData : g_pServerLimits->m_UnconnectedPlayerLimitData)
+		{
+			if (!memcmp(packet->adr.ip, foundSendData.ip, 16))
+			{
+				sendData = &foundSendData;
+				break;
+			}
+		}
+
+		if (!sendData)
+		{
+			sendData = &g_pServerLimits->m_UnconnectedPlayerLimitData.emplace_back();
+			memcpy(sendData->ip, packet->adr.ip, 16);
+		}
+
+		if (Tier0::Plat_FloatTime() < sendData->timeoutEnd)
+			return false;
+
+		if (Tier0::Plat_FloatTime() - sendData->lastQuotaStart >= 1.0)
+		{
+			sendData->lastQuotaStart = Tier0::Plat_FloatTime();
+			sendData->packetCount = 0;
+		}
+
+		sendData->packetCount++;
+
+		if (sendData->packetCount >= g_pServerLimits->Cvar_sv_querylimit_per_sec->GetInt())
+		{
+			spdlog::warn(
+				"Client went over connectionless ratelimit of {} per sec with packet of type {}",
+				g_pServerLimits->Cvar_sv_querylimit_per_sec->GetInt(),
+				packet->data[4]);
+
+			// timeout for a minute
+			sendData->timeoutEnd = Tier0::Plat_FloatTime() + 60.0;
+			return false;
+		}
+	}
+
+	return ProcessConnectionlessPacket(a1, packet);
+}
+
+// this is weird and i'm not sure if it's correct, so not using for now
+/*AUTOHOOK(CBasePlayer__PhysicsSimulate, server.dll + 0x5A6E50, bool, __fastcall, (void* self, int a2, char a3))
+{
+	spdlog::info("CBasePlayer::PhysicsSimulate");
+	return CBasePlayer__PhysicsSimulate(self, a2, a3);
+}*/
+
+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;
+};
+
+// clang-format off
+AUTOHOOK(CPlayerMove__RunCommand, server.dll + 0x5B8100,
+void, __fastcall, (void* self, R2::CBasePlayer* player, SV_CUserCmd* pUserCmd, uint64_t a4))
+// clang-format on
+{
+	if (g_pServerLimits->Cvar_sv_antispeedhack_enable->GetBool())
+	{
+		R2::CBaseClient* pClient = &R2::g_pClientArray[player->m_nPlayerIndex - 1];
+
+		if (g_pServerLimits->m_PlayerLimitData.find(pClient) != g_pServerLimits->m_PlayerLimitData.end())
+		{
+			PlayerLimitData* pLimitData = &g_pServerLimits->m_PlayerLimitData[pClient];
+
+			pLimitData->flFrameUserCmdBudget = fmax(0.0, pLimitData->flFrameUserCmdBudget - pUserCmd->frameTime);
+
+			if (pLimitData->flFrameUserCmdBudget <= 0.0)
+			{
+				spdlog::warn("player {} went over usercmd budget ({})", pClient->m_Name, pLimitData->flFrameUserCmdBudget);
+				return;
+			}
+			// else
+			//	spdlog::info("{}: {}", pClient->m_Name, pLimitData->flFrameUserCmdBudget);
+		}
+	}
+
+	CPlayerMove__RunCommand(self, player, pUserCmd, a4);
+}
+
+ON_DLL_LOAD_RELIESON("engine.dll", ServerLimits, ConVar, (CModule module))
+{
+	AUTOHOOK_DISPATCH_MODULE(engine.dll)
+
+	g_pServerLimits = new ServerLimitsManager;
+
+	g_pServerLimits->CVar_sv_quota_stringcmdspersecond = new ConVar(
+		"sv_quota_stringcmdspersecond",
+		"60",
+		FCVAR_GAMEDLL,
+		"How many string commands per second clients are allowed to submit, 0 to disallow all string commands, -1 to disable");
+	g_pServerLimits->Cvar_net_chan_limit_mode =
+		new ConVar("net_chan_limit_mode", "0", FCVAR_GAMEDLL, "The mode for netchan processing limits: 0 = warn, 1 = kick");
+	g_pServerLimits->Cvar_net_chan_limit_msec_per_sec = new ConVar(
+		"net_chan_limit_msec_per_sec",
+		"100",
+		FCVAR_GAMEDLL,
+		"Netchannel processing is limited to so many milliseconds, abort connection if exceeding budget");
+	g_pServerLimits->Cvar_sv_querylimit_per_sec = new ConVar("sv_querylimit_per_sec", "15", FCVAR_GAMEDLL, "");
+	g_pServerLimits->Cvar_sv_max_chat_messages_per_sec = new ConVar("sv_max_chat_messages_per_sec", "5", FCVAR_GAMEDLL, "");
+	g_pServerLimits->Cvar_sv_antispeedhack_enable =
+		new ConVar("sv_antispeedhack_enable", "0", FCVAR_NONE, "whether to enable antispeedhack protections");
+	g_pServerLimits->Cvar_sv_antispeedhack_maxtickbudget = new ConVar(
+		"sv_antispeedhack_maxtickbudget",
+		"64",
+		FCVAR_GAMEDLL,
+		"Maximum number of client-issued usercmd ticks that can be replayed in packet loss conditions, 0 to allow no restrictions");
+	g_pServerLimits->Cvar_sv_antispeedhack_budgetincreasemultiplier = new ConVar(
+		"sv_antispeedhack_budgetincreasemultiplier",
+		"1.2",
+		FCVAR_GAMEDLL,
+		"Increase usercmd processing budget by tickinterval * value per tick");
+}
+
+ON_DLL_LOAD("server.dll", ServerLimitsServer, (CModule module))
+{
+	AUTOHOOK_DISPATCH_MODULE(server.dll)
+}
diff --git a/NorthstarDLL/shared/exploit_fixes/ns_limits.h b/NorthstarDLL/shared/exploit_fixes/ns_limits.h
new file mode 100644
index 00000000..bbc0a85f
--- /dev/null
+++ b/NorthstarDLL/shared/exploit_fixes/ns_limits.h
@@ -0,0 +1,51 @@
+#pragma once
+#include "engine/r2engine.h"
+#include "core/convar/convar.h"
+#include <unordered_map>
+
+struct PlayerLimitData
+{
+	double lastClientCommandQuotaStart = -1.0;
+	int numClientCommandsInQuota = 0;
+
+	double lastNetChanProcessingLimitStart = -1.0;
+	double netChanProcessingLimitTime = 0.0;
+
+	double lastSayTextLimitStart = -1.0;
+	int sayTextLimitCount = 0;
+
+	float flFrameUserCmdBudget = 0.0;
+};
+
+struct UnconnectedPlayerLimitData
+{
+	char ip[16];
+	double lastQuotaStart = 0.0;
+	int packetCount = 0;
+	double timeoutEnd = -1.0;
+};
+
+class ServerLimitsManager
+{
+  public:
+	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;
+	ConVar* Cvar_sv_max_chat_messages_per_sec;
+	ConVar* Cvar_sv_antispeedhack_enable;
+	ConVar* Cvar_sv_antispeedhack_maxtickbudget;
+	ConVar* Cvar_sv_antispeedhack_budgetincreasemultiplier;
+
+	std::unordered_map<R2::CBaseClient*, PlayerLimitData> m_PlayerLimitData;
+	std::vector<UnconnectedPlayerLimitData> m_UnconnectedPlayerLimitData;
+
+  public:
+	void RunFrame(double flCurrentTime, float flFrameTime);
+	void AddPlayer(R2::CBaseClient* player);
+	void RemovePlayer(R2::CBaseClient* player);
+	bool CheckStringCommandLimits(R2::CBaseClient* player);
+	bool CheckChatLimits(R2::CBaseClient* player);
+};
+
+extern ServerLimitsManager* g_pServerLimits;