--- server/scripting/script.c	2010-02-21 19:35:39.000000000 +0100

+++ server/scripting/script.c.old	2010-06-06 09:30:51.000000000 +0200

@@ -44,6 +44,48 @@

 /**************************************************************************

+  Unsafe Lua builtin symbols that we to remove access to.

+

+  If Freeciv's Lua version changes, you have to check how the set of

+  unsafe functions and modules changes in the new version. Update the list of

+  loaded libraries in script_lualibs, then update the unsafe symbols blacklist

+  in script_unsafe_symbols.

+

+  Once the variables are updated for the new version, update the value of

+  SCRIPT_SECURE_LUA_VERSION

+

+  In general, unsafe is all functionality that gives access to:

+  * Reading files and running processes

+  * Loading lua files or libraries

+**************************************************************************/

+#define SCRIPT_SECURE_LUA_VERSION 501

+

+static const char *script_unsafe_symbols[] = {

+  "dofile",

+  "loadfile",

+  NULL

+};

+

+#if LUA_VERSION_NUM != SCRIPT_SECURE_LUA_VERSION

+#warning "The script runtime's unsafe symbols information is not up to date."

+#warning "This can be a big security hole!"

+#endif

+

+/**************************************************************************

+  Lua libraries to load (all default libraries, excluding operating system

+  and library loading modules). See linit.c in Lua 5.1 for the default list.

+**************************************************************************/

+static luaL_Reg script_lualibs[] = {

+  /* Using default libraries excluding: package, io and os */

+  {"", luaopen_base},

+  {LUA_TABLIBNAME, luaopen_table},

+  {LUA_STRLIBNAME, luaopen_string},

+  {LUA_MATHLIBNAME, luaopen_math},

+  {LUA_DBLIBNAME, luaopen_debug},

+  {NULL, NULL}

+};

+

+/**************************************************************************

   Report a lua error.

 **************************************************************************/

 static int script_report(lua_State *L, int status, const char *code)

@@ -383,6 +425,31 @@

 }

 /**************************************************************************

+  Open lua libraries in the array of library definitions in llib.

+**************************************************************************/

+static void script_openlibs(lua_State *L, const luaL_Reg *llib)

+{

+  for (; llib->func; llib++) {

+    lua_pushcfunction(L, llib->func);

+    lua_pushstring(L, llib->name);

+    lua_call(L, 1, 0);

+  }

+}

+

+/**************************************************************************

+  Remove global symbols from lua state L

+**************************************************************************/

+static void script_blacklist(lua_State *L, const char *lsymbols[])

+{

+  int i;

+

+  for (i = 0; lsymbols[i] != NULL; i++) {

+    lua_pushnil(L);

+    lua_setglobal(L, lsymbols[i]);

+  }

+}

+

+/**************************************************************************

   Initialize the scripting state.

 **************************************************************************/

 bool script_init(void)

@@ -393,7 +460,8 @@

       return FALSE;

     }

-    luaL_openlibs(state);

+    script_openlibs(state, script_lualibs);

+    script_blacklist(state, script_unsafe_symbols);

     tolua_api_open(state);