Closed Mixesoft closed 1 year ago
Yes this is intended.
Why does the fenced frame require all the permissions set for the topmost frame?
It does not require "all the permissions". Please see https://github.com/WICG/fenced-frame/blob/master/explainer/README.md#security-considerations which points to a document that describes in detail which sandbox flags must be allowed for an embedding environment to be considered suitable for a fenced frame. At the moment the set is static across fenced frames but will soon be actually defined by each config-generating API (i.e., Protected Audience and Shared Storage at the moment), who define which sandbox flags must be enabled for a given FencedFrameConfig object to load in an environment. These considerations are made based on what the content represented by each FencedFrameConfig expects to be able to do in its environment.
Thanks for the detailed answer! It's just that currently we can't use sandbox for the topmost window., because AdSense code (https://securepubads.g.doubleclick.net/static/topics/topics_frame.html) can't create fenced frame.
You can use CSP sandbox flags, just limited to a certain set of flags. If we allowed any flags, including ones that prevented ads from doing what they expect or need to do, this could be used as a trivial communication channel between the top page and the ad, which harms user privacy and is precisely the thing we're trying to prevent with this proposal. If possible, using a more lenient set of flags would be the best way forward.
I'm going to close this since I don't think there is any action we can take here that won't compromise user privacy. Please feel free to comment further or re-open the issue if you'd like to continue the dialogue, as we're happy to help further if we can.
When the topmost frame document have the following CSP header: Content-Security-Policy: sandbox allow-same-origin allow-scripts allow-top-navigation-by-user-activation;
In the Chrome console the following warning appears: Can't create a fenced frame. A sandboxed document can load fenced frames only when all of the following permissions are set: allow-same-origin, allow-forms, allow-scripts, allow-popups, allow-popups-to-escape-sandbox and allow-top-navigation-by-user-activation.
Latest Chrome stable channel, Privacy Sandbox trial on. Is this the intended functionality? Why does the fenced frame require all the permissions set for the topmost frame? it's a lack of security at all for the top frame. So what is the goal then?