[webkit-dev] ExecState::thisObject()

[Adam Barth]

On Mon, Jul 13, 2009 at 4:59 PM, Maciej Stachowiak<mjs at apple.com> wrote:
> If security is one motivation for this work, then I'd like us to understand
> the pattern we want to use for cross-origin-accessible objects. Should they
> use the "home global object" prototype but protect it from mutation or
> access to extended properties, should they use the prototype of the
> referencing frame (lexical global object) or something else?

I can study this question, but I believe Firefox solves this problem
by having cross-origin viewers of these properties see a "fresh" copy
of the object that isn't === the object as seen by same-origin
viewers.  The fresh copy ignores any changes the page might has made
to the object and has a prototype chain connects to the viewer's
prototypes.  If two different cross-origin viewers look at the same
object, they each see fresh copies.

> Doing the change incrementally seems wise, if it is feasible to do so. Maybe
> even a patch demonstrating how it would work for a single class could be a
> good way to evaluate the change. Perhaps separate trailblazing examples
> could be given for both an ordinary class and one that is cross-origin
> accessible.

Sounds like a plan.

Thanks for all your input on this topic.

Adam