Re: Loose sandbox

[Luiz Henrique de Figueiredo <lhf@...>]

> I am writing a program where an external user script is loaded and
> executed. Therefore it is AFAIK good practice to implement a sandbox which
> restricts the user to use only a certain set of functions. Still I would
> like to enable the user to use most of Lua's functions and restrict only
> those functions which would enable the user to break the sandbox and e.g.
> access _G.

Here's what is done in http://www.lua.org/cgi-bin/demo :

local E=debug.getregistry()
E._LOADED={}
E._LOADLIB=nil
E=nil
arg=nil
debug.debug=nil
debug.getregistry=nil
dofile=nil
io={write=io.write}
loadfile=nil
os.execute=nil
os.getenv=nil
os.remove=nil
os.rename=nil
os.tmpname=nil
package=nil
require=nil