Filter evil characters in name and message (bug 5912, bug 6301)

amxmodx/amxmodx.h

@@ -142,6 +142,7 @@ unsigned int UTIL_ReplaceAll(char *subject, size_t maxlength, const char *search
 char *UTIL_ReplaceEx(char *subject, size_t maxLen, const char *search, size_t searchLen, const char *replace, size_t replaceLen, bool caseSensitive);
 void UTIL_TrimLeft(char *buffer);
 void UTIL_TrimRight(char *buffer);
+size_t UTIL_FilterEvilCharacters(const char *in, char *out, size_t out_maxlen, bool name_only);
 
 #define GET_PLAYER_POINTER(e)   (&g_players[ENTINDEX(e)])
 //#define GET_PLAYER_POINTER(e)   (&g_players[(((int)e-g_edict_point)/sizeof(edict_t))])

amxmodx/meta_api.cpp

@@ -149,6 +149,7 @@ int FF_ClientConnectEx = -1;
 
 IFileSystem* g_FileSystem;
 HLTypeConversion TypeConversion;
+server_static_t *ServerStatic;
 
 bool ColoredMenus(const char *ModName)
 {
@@ -929,6 +930,27 @@ void C_ClientPutInServer_Post(edict_t *pEntity)
 	RETURN_META(MRES_IGNORED);
 }
 
+void C_ClientUserInfoChanged_Pre(edict_t *pEntity, char *infobuffer)
+{
+	if (ServerStatic)
+	{
+		auto clientIndex = TypeConversion.edict_to_id(pEntity);
+
+		const char *oldName = ServerStatic->clients[clientIndex - 1].name;
+		const char *newName = INFOKEY_VALUE(infobuffer, "name");
+
+		if (oldName[0] == '\0' || strcmp(newName, oldName) != 0)
+		{
+			char safeNewName[MAX_NAME];
+			UTIL_FilterEvilCharacters(newName, safeNewName, sizeof(safeNewName), true);
+
+			SET_CLIENT_KEYVALUE(clientIndex, infobuffer, "name", safeNewName);
+		}
+	}
+
+	RETURN_META(MRES_IGNORED);
+}
+
 void C_ClientUserInfoChanged_Post(edict_t *pEntity, char *infobuffer)
 {
 	CPlayer *pPlayer = GET_PLAYER_POINTER(pEntity);
@@ -1009,6 +1031,19 @@ void C_ClientCommand(edict_t *pEntity)
 		}
 	}
 
+	if (!strcmp(cmd, "say") || !strcmp(cmd, "say_team"))
+	{
+		auto args = CMD_ARGS();
+
+		if (args && *args)
+		{
+			char safeMessage[128];
+			auto length = UTIL_FilterEvilCharacters(args, safeMessage, sizeof(safeMessage), false);
+
+			memcpy(const_cast<char*>(args), safeMessage, length + 1);
+		}
+	}
+
 	if (executeForwards(FF_ClientCommand, static_cast<cell>(pPlayer->index)) > 0)
 		RETURN_META(MRES_SUPERCEDE);
 
@@ -1586,15 +1621,37 @@ C_DLLEXPORT	int	Meta_Attach(PLUG_LOADTIME now, META_FUNCTIONS *pFunctionTable, m
 
 	g_CvarManager.CreateCvarHook();
 
-	void *address = nullptr;
-
-	if (CommonConfig && CommonConfig->GetMemSig("SV_DropClient", &address) && address)
+	if (CommonConfig)
 	{
-		DropClientDetour = DETOUR_CREATE_STATIC_FIXED(SV_DropClient, address);
-	}
-	else
-	{
-		AMXXLOG_Log("client_disconnected forward has been disabled - check your gamedata files.");
+		void *address = nullptr;
+
+#if defined(KE_WINDOWS)
+		TypeDescription typeDesc;
+
+		if (CommonConfig->GetOffset("svs", &typeDesc))
+		{
+			auto base = *reinterpret_cast<uintptr_t*>(reinterpret_cast<byte*>(g_engfuncs.pfnGetCurrentPlayer) + typeDesc.fieldOffset);
+			ServerStatic = reinterpret_cast<decltype(ServerStatic)>(base - 4);
+		}
+#else
+		if (CommonConfig->GetMemSig("svs", &address))
+		{
+			ServerStatic = reinterpret_cast<decltype(ServerStatic)>(address);
+		}
+#endif
+		else
+		{
+			AMXXLOG_Log("svs global variable is not available - check your gamedata files.");
+		}
+
+		if (CommonConfig->GetMemSig("SV_DropClient", &address) && address)
+		{
+			DropClientDetour = DETOUR_CREATE_STATIC_FIXED(SV_DropClient, address);
+		}
+		else
+		{
+			AMXXLOG_Log("client_disconnected forward has been disabled - check your gamedata files.");
+		}
 	}
 
 	GET_IFACE<IFileSystem>("filesystem_stdio", g_FileSystem, FILESYSTEM_INTERFACE_VERSION);
@@ -1739,6 +1796,7 @@ C_DLLEXPORT	int	GetEntityAPI2(DLL_FUNCTIONS *pFunctionTable, int *interfaceVersi
 	gFunctionTable.pfnInconsistentFile = C_InconsistentFile;
 	gFunctionTable.pfnServerActivate = C_ServerActivate;
 	gFunctionTable.pfnClientConnect = C_ClientConnect;
+	gFunctionTable.pfnClientUserInfoChanged = C_ClientUserInfoChanged_Pre;
 
 	memcpy(pFunctionTable, &gFunctionTable, sizeof(DLL_FUNCTIONS));
 

amxmodx/util.cpp

@@ -717,4 +717,42 @@ void UTIL_TrimRight(char *buffer)
 			}
 		}
 	}
-}
+}
+
+size_t UTIL_FilterEvilCharacters(const char *in, char *out, size_t out_maxlen, bool name_only)
+{
+	auto remainChars = out_maxlen - 1;
+	auto n = 0;
+
+	for (auto s = in; *s != '\0' && remainChars; ++s)
+	{
+		if (*s == '#' ||
+			*s == '%' ||
+			(name_only &&
+				*s == '&' ||
+				(n && out[n - 1] == '+' && static_cast<signed char>(*s) > 0 && isalnum(*s))
+			))
+		{
+			if (remainChars < 3)
+			{
+				break;
+			}
+
+			// http://unicode-table.com/blocks/halfwidth-and-fullwidth-forms/
+			out[n++] = 0xEF;
+			out[n++] = 0xBC | (((*s - 0x20) & 0x40) >> 6);
+			out[n++] = 0x80 + ((*s - 0x20) & 0x3F);
+
+			remainChars -= 3;
+		}
+		else
+		{
+			out[n++] = *s;
+			remainChars--;
+		}
+	}
+
+	out[n] = '\0';
+
+	return n;
+}