diff options
Diffstat (limited to 'NorthstarDLL/exploitfixes.cpp')
| -rw-r--r-- | NorthstarDLL/exploitfixes.cpp | 435 |
1 files changed, 435 insertions, 0 deletions
diff --git a/NorthstarDLL/exploitfixes.cpp b/NorthstarDLL/exploitfixes.cpp new file mode 100644 index 00000000..fbe91e3b --- /dev/null +++ b/NorthstarDLL/exploitfixes.cpp @@ -0,0 +1,435 @@ +#include "pch.h"
+#include "NSMem.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 (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 = 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::CBasePlayer* 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, (HMODULE baseAddress))
+{
+ AUTOHOOK_DISPATCH_MODULE(engine.dll)
+
+ CCommand__Tokenize = (bool(*)(CCommand&, const char*, R2::cmd_source_t))((char*)baseAddress + 0x418380);
+
+ // allow client/ui to run clientcommands despite restricting servercommands
+ NSMem::BytePatch((uintptr_t)baseAddress + 0x4FB65, "EB 11");
+ NSMem::BytePatch((uintptr_t)baseAddress + 0x4FBAC, "EB 16");
+
+ // patch to set bWasWritingStringTableSuccessful in CNetworkStringTableContainer::WriteBaselines if it fails
+ {
+ uintptr_t writeAddress = (uintptr_t)(&bWasWritingStringTableSuccessful - ((uintptr_t)baseAddress + 0x234EDC));
+
+ auto addr = (uintptr_t)baseAddress + 0x234ED2;
+ NSMem::BytePatch(addr, "C7 05");
+ NSMem::BytePatch(addr + 2, (BYTE*)&writeAddress, sizeof(writeAddress));
+
+ NSMem::BytePatch(addr + 6, "00 00 00 00");
+
+ NSMem::NOP(addr + 10, 5);
+ }
+}
+
+ON_DLL_LOAD_RELIESON("server.dll", ServerExploitFixes, ConVar, (HMODULE baseAddress))
+{
+ 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
+ NSMem::BytePatch((uintptr_t)baseAddress + 0x153920, "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)
+ {
+ uintptr_t address = (uintptr_t)GetProcAddress(baseAddress, 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);
+ }
+ }
+
+ 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 |