diff options
Diffstat (limited to 'NorthstarDLL/exploitfixes.cpp')
-rw-r--r-- | NorthstarDLL/exploitfixes.cpp | 911 |
1 files changed, 481 insertions, 430 deletions
diff --git a/NorthstarDLL/exploitfixes.cpp b/NorthstarDLL/exploitfixes.cpp index c9f7dd61..8b5783d6 100644 --- a/NorthstarDLL/exploitfixes.cpp +++ b/NorthstarDLL/exploitfixes.cpp @@ -1,430 +1,481 @@ -#include "pch.h"
-#include "cvar.h"
-#include "limits.h"
-#include "dedicated.h"
-#include "tier0.h"
-#include "r2engine.h"
-#include "r2client.h"
-
-AUTOHOOK_INIT()
-
-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; \
- }())
-
-// Make sure 3 or less floats are valid
-bool ValidateFloats(float a, float b = 0, float c = 0)
-{
- return !isnan(a) && !isnan(b) && !isnan(c);
-}
-
-struct Vector
-{
- float x, y, z;
-
- Vector(float x = 0, float y = 0, float z = 0) : x(x), y(y), z(z) {}
-
- bool IsValid()
- {
- return ValidateFloats(x, y, z);
- }
-};
-
-struct Angle
-{
- float pitch, yaw, roll;
-
- Angle(float pitch = 0, float yaw = 0, float roll = 0) : pitch(pitch), yaw(yaw), roll(roll) {}
-
- bool IsInvalid()
- {
- return !ValidateFloats(pitch, yaw, roll);
-
- if (!ValidateFloats(pitch, yaw, roll))
- return false;
-
- return (pitch > 90 || pitch < -90) || (yaw > 180 || yaw < -180) || (roll > 180 || roll < -180);
- }
-};
-
-// block bad netmessages
-// Servers can literally request a screenshot from any client, yeah no
-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
-{
- return false;
-}
-
-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
-{
- return false;
-}
-
-// This is unused ingame and a big client=>server=>client exploit vector
-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
-{
- return false;
-}
-
-AUTOHOOK(CClient_ProcessSetConVar, engine.dll + 0x75CF0,
-bool, __fastcall, (void* pMsg)) // 48 8B D1 48 8B 49 18 48 8B 01 48 FF 60 10
-{
-
- 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");
-
- auto realVar = R2::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 (bIsServerFrame)
- {
- if (realVar)
- isValidFlags = realVar->IsFlagSet(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 CClient_ProcessSetConVar(msg);
-}
-
-// prevent invalid user CMDs
-AUTOHOOK(CClient_ProcessUsercmds, engine.dll + 0x1040F0,
-bool, __fastcall, (void* thisptr, void* pMsg)) // 40 55 56 48 83 EC 58
-{
- 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 << ")");
- }
-
- // removing, as vanilla already limits num usercmds per frame
- /*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 CClient_ProcessUsercmds(thisptr, pMsg);
-}
-
-AUTOHOOK(ReadUsercmd, server.dll + 0x2603F0,
-void, __fastcall, (void* buf, void* pCmd_move, void* pCmd_from)) // 4C 89 44 24 ? 53 55 56 57
-{
- // 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 __declspec(align(4)) SV_CUserCmd
- {
- DWORD command_number;
- DWORD tick_count;
- float command_time;
- Angle worldViewAngles;
- BYTE gap18[4];
- Angle localViewAngles;
- Angle attackangles;
- Vector move;
- DWORD buttons;
- BYTE impulse;
- short weaponselect;
- DWORD meleetarget;
- BYTE gap4C[24];
- char headoffset;
- BYTE gap65[11];
- Vector cameraPos;
- Angle 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) + "): ";
-
- if (cmd->worldViewAngles.IsInvalid())
- {
- BLOCKED_INFO("CMD has invalid worldViewAngles");
- goto INVALID_CMD;
- }
-
- if (cmd->attackangles.IsInvalid())
- {
- BLOCKED_INFO("CMD has invalid attackangles");
- goto INVALID_CMD;
- }
-
- if (cmd->localViewAngles.IsInvalid())
- {
- BLOCKED_INFO("CMD has invalid localViewAngles");
- goto INVALID_CMD;
- }
-
- if (cmd->cameraAngles.IsInvalid())
- {
- BLOCKED_INFO("CMD has invalid cameraAngles");
- goto INVALID_CMD;
- }
-
- 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
- }
-
- if (!cmd->move.IsValid())
- {
- BLOCKED_INFO("Invalid move vector");
- goto INVALID_CMD;
- }
-
- if (!cmd->cameraPos.IsValid())
- {
- BLOCKED_INFO("Invalid cameraPos"); // IIRC this can crash spectating clients or anyone watching replays
- goto INVALID_CMD;
- }
-
- 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 = Angle(0, 0, 0);
- cmd->tick_count = cmd->frameTime = 0;
- cmd->move = cmd->cameraPos = Vector(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
-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
-{
- return (!strcmp("r2", pModName) || !strcmp("r1", pModName))
- && !Tier0::CommandLine()->CheckParm("-norestrictservercommands");
-}
-
-// ratelimit stringcmds, and prevent remote clients from calling non-FCVAR_GAMEDLL_FOR_REMOTE_CLIENTS commands
-bool (*CCommand__Tokenize)(CCommand& self, const char* pCommandString, R2::cmd_source_t commandSource);
-AUTOHOOK(CGameClient__ExecuteStringCommand,
-engine.dll + 0x1022E0, bool, , (R2::CBaseClient* self, uint32_t unknown, const char* 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;
- }
-
- return CGameClient__ExecuteStringCommand(self, unknown, pCommandString);
-}
-
-// prevent clients from crashing servers through overflowing CNetworkStringTableContainer::WriteBaselines
-bool bWasWritingStringTableSuccessful;
-AUTOHOOK(CBaseClient__SendServerInfo,
-engine.dll + 0x104FB0, void, , (void* self))
-{
- bWasWritingStringTableSuccessful = true;
- CBaseClient__SendServerInfo(self);
- if (!bWasWritingStringTableSuccessful)
- R2::CBaseClient__Disconnect(
- self, 1, "Overflowed CNetworkStringTableContainer::WriteBaselines, try restarting your client and reconnecting");
-}
-
-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);
- }
- }
-
- ns_exploitfixes_log =
- new ConVar("ns_exploitfixes_log", "1", FCVAR_GAMEDLL, "Whether to log whenever ExploitFixes.cpp blocks/corrects something");
-}
\ No newline at end of file +#include "pch.h" +#include "cvar.h" +#include "limits.h" +#include "dedicated.h" +#include "tier0.h" +#include "r2engine.h" +#include "r2client.h" + +AUTOHOOK_INIT() + +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; \ + }()) + +// Make sure 3 or less floats are valid +bool ValidateFloats(float a, float b = 0, float c = 0) +{ + return !isnan(a) && !isnan(b) && !isnan(c); +} + +struct Vector +{ + float x, y, z; + + Vector(float x = 0, float y = 0, float z = 0) : x(x), y(y), z(z) {} + + bool IsValid() + { + return ValidateFloats(x, y, z); + } +}; + +struct Angle +{ + float pitch, yaw, roll; + + Angle(float pitch = 0, float yaw = 0, float roll = 0) : pitch(pitch), yaw(yaw), roll(roll) {} + + bool IsInvalid() + { + return !ValidateFloats(pitch, yaw, roll); + + if (!ValidateFloats(pitch, yaw, roll)) + return false; + + return (pitch > 90 || pitch < -90) || (yaw > 180 || yaw < -180) || (roll > 180 || roll < -180); + } +}; + +// block bad netmessages +// Servers can literally request a screenshot from any client, yeah no +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 +{ + return false; +} + +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 +{ + return false; +} + +// This is unused ingame and a big client=>server=>client exploit vector +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 +{ + return false; +} + +AUTOHOOK(CClient_ProcessSetConVar, engine.dll + 0x75CF0, +bool, __fastcall, (void* pMsg)) // 48 8B D1 48 8B 49 18 48 8B 01 48 FF 60 10 +{ + + 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"); + + auto realVar = R2::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 (bIsServerFrame) + { + if (realVar) + isValidFlags = realVar->IsFlagSet(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 CClient_ProcessSetConVar(msg); +} + +// prevent invalid user CMDs +AUTOHOOK(CClient_ProcessUsercmds, engine.dll + 0x1040F0, +bool, __fastcall, (void* thisptr, void* pMsg)) // 40 55 56 48 83 EC 58 +{ + 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 << ")"); + } + + // removing, as vanilla already limits num usercmds per frame + /*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 CClient_ProcessUsercmds(thisptr, pMsg); +} + +AUTOHOOK(ReadUsercmd, server.dll + 0x2603F0, +void, __fastcall, (void* buf, void* pCmd_move, void* pCmd_from)) // 4C 89 44 24 ? 53 55 56 57 +{ + // 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 __declspec(align(4)) SV_CUserCmd + { + DWORD command_number; + DWORD tick_count; + float command_time; + Angle worldViewAngles; + BYTE gap18[4]; + Angle localViewAngles; + Angle attackangles; + Vector move; + DWORD buttons; + BYTE impulse; + short weaponselect; + DWORD meleetarget; + BYTE gap4C[24]; + char headoffset; + BYTE gap65[11]; + Vector cameraPos; + Angle 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) + "): "; + + if (cmd->worldViewAngles.IsInvalid()) + { + BLOCKED_INFO("CMD has invalid worldViewAngles"); + goto INVALID_CMD; + } + + if (cmd->attackangles.IsInvalid()) + { + BLOCKED_INFO("CMD has invalid attackangles"); + goto INVALID_CMD; + } + + if (cmd->localViewAngles.IsInvalid()) + { + BLOCKED_INFO("CMD has invalid localViewAngles"); + goto INVALID_CMD; + } + + if (cmd->cameraAngles.IsInvalid()) + { + BLOCKED_INFO("CMD has invalid cameraAngles"); + goto INVALID_CMD; + } + + 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 + } + + if (!cmd->move.IsValid()) + { + BLOCKED_INFO("Invalid move vector"); + goto INVALID_CMD; + } + + if (!cmd->cameraPos.IsValid()) + { + BLOCKED_INFO("Invalid cameraPos"); // IIRC this can crash spectating clients or anyone watching replays + goto INVALID_CMD; + } + + 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 = Angle(0, 0, 0); + cmd->tick_count = cmd->frameTime = 0; + cmd->move = cmd->cameraPos = Vector(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 +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 +{ + return (!strcmp("r2", pModName) || !strcmp("r1", pModName)) + && !Tier0::CommandLine()->CheckParm("-norestrictservercommands"); +} + +// ratelimit stringcmds, and prevent remote clients from calling non-FCVAR_GAMEDLL_FOR_REMOTE_CLIENTS commands +bool (*CCommand__Tokenize)(CCommand& self, const char* pCommandString, R2::cmd_source_t commandSource); +AUTOHOOK(CGameClient__ExecuteStringCommand, +engine.dll + 0x1022E0, bool, , (R2::CBaseClient* self, uint32_t unknown, const char* pCommandString)) +{ + static ConVar* Cvar_sv_cheats = R2::g_pCVar->FindVar("sv_cheats"); // doing this here is temp + + 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; +AUTOHOOK(CBaseClient__SendServerInfo, +engine.dll + 0x104FB0, void, , (void* self)) +{ + 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 +AUTOHOOK(GetEntByIndex, engine.dll + 0x2A8A50, +void*,, (int i)) +{ + 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); +} + +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); + } + } + + ns_exploitfixes_log = + new ConVar("ns_exploitfixes_log", "1", FCVAR_GAMEDLL, "Whether to log whenever ExploitFixes.cpp blocks/corrects something"); +} |