On Dec 31, 2012, at 7:28 AM, Brandon Benvie wrote:
>
> On Monday, December 31, 2012, Tom Van Cutsem wrote:
> That said, I think this issue is orthogonal to our choice of whether or not
> to expose "setPrototypeOf" as part of the MOP. Even if we do expose it, any
> sandbox that wants to take away the ability the set the prototype can simply
> poison Reflect.setPrototypeOf in addition to deleting
> Object.prototype.__proto__.
>
> Ive realized this is actually a potentially serious flaw with the module
> system with regards to how the builtin modules expose features. If you
> introduce Reflect.setPrototypeOf (or more generally, anything exposed as an
> export of a system module) there is no way for something like SES (user
> level) to remove access to it. There's no way to monkey patch these things or
> remove them or add new features to them because the modules aren't externally
> mutable. `delete Reflect.setPrototypeOf` is not currently an option.
I'll leave it to Dave or Sam to elaborate, but I don't think this is correct.
My understanding, is that such censoring can be accomplished by configuring a
module loader to return an alternative implementation of the "@Reflect" (or
however it is identified) which could either not export Reflect.setPrototypeOf
or export an alternative implementation.
Allen
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