Apple goes least authority in “Lion”

[kpreid]

Whoa. They even called it a powerbox as we do.

Apple has chosen to solve this problem by providing heightened permissions to a particular class of actions: those explicitly initiated by the user. Lion includes a trusted daemon process called Powerbox (pboxd) whose job is to present and control open/save dialog boxes on behalf of sandboxed applications. After the user selects a file or directory into which a file should be saved, Powerbox pokes a hole in the application sandbox that allows it to perform the specific action.

— Mac OS X 10.7 Lion: the Ars Technica review

It probably ain't capabilities (no bundling of designation of the resource with authority to access it, unless they've replaced file pathnames, which I doubt), but it's a big step in a good direction. UPDATE: Ivan Krstić says “The implementation uses actual capabilities under the hood.”