Enable safe Os functions

Author: Dezash

Server/mods/deathmatch/logic/lua/CLuaMain.cpp

@@ -172,6 +172,23 @@ void CLuaMain::InitVM(void)
     luaopen_table(m_luaVM);
     luaopen_debug(m_luaVM);
     luaopen_utf8(m_luaVM);
+    luaopen_os(m_luaVM);
+
+    // Disable dangerous Lua Os library functions
+    lua_getglobal(m_luaVM, "os");
+    lua_pushnil(m_luaVM);
+    lua_setfield(m_luaVM, -2, "execute");
+    lua_pushnil(m_luaVM);
+    lua_setfield(m_luaVM, -2, "rename");
+    lua_pushnil(m_luaVM);
+    lua_setfield(m_luaVM, -2, "remove");
+    lua_pushnil(m_luaVM);
+    lua_setfield(m_luaVM, -2, "exit");
+    lua_pushnil(m_luaVM);
+    lua_setfield(m_luaVM, -2, "getenv");
+    lua_pushnil(m_luaVM);
+    lua_setfield(m_luaVM, -2, "tmpname");
+    lua_pop(m_luaVM, 1);
 
     // Initialize security restrictions. Very important to prevent lua trojans and viruses!
     InitSecurity();