Re: Secure tables in Lua: Summary

[Diego Nehab <diego@...>]

Hi,

> Your example suffers from the same issue. Take the following code:
>
> t = get_secure_table()
> mt = getmetatable(t)
> oldindex = mt.__index
> mt.__index = function(t, k)
>  log_key(k)
> end
> setmetatable(t, mt)

If the object's metatable has a "__metatable" field,
getmetatable() returns the associated value.  Can't you use
this trick to protect the datastructure? setmetatable() will
also honor __metatable by raising an error.

[]s,
Diego