Bug 183292 – Investigate usage of XMLHttpRequest's Permissions Policy usage

• Component: DOM
• Status: RESOLVED DUPLICATE

[Ian Clelland]

XMLHttpRequest objects can have their behavior controlled by feature policy
(https://github.com/whatwg/xhr/pull/177, not merged yet)

If the policy in the active document disallows the 'sync-xhr' feature, then calling .send() on the XMLHttpRequest object should throw a NetworkError (and ideally log a message to the developer console)

Demo: https://xhr.featurepolicy.rocks/
GitHub issue: https://github.com/whatwg/xhr/issues/178
Web Platform Tests: https://wpt.fyi/xhr/xmlhttprequest-sync-default-feature-policy.sub.html

Feature policy itself has been partially implemented as part of https://bugs.webkit.org/show_bug.cgi?id=167430, but I haven't found another bug for the rest of the implementation. Let me know if I should file that as well.

[youenn fablet]

Hi Ian,

I guess that if there are other bugs related to feature policy that are filed, maybe having an umbrella bug might be useful.

The current feature policy "implementation" is minimal in that it only checks for the iframe attribute, (no headers checking) and is specific to media capture.

[Ian Clelland]

Thanks, Youenn --- I filed https://bugs.webkit.org/show_bug.cgi?id=183300; I'm not sure if bugzilla allows me to declare a dependency of this bug on that one.

[Anne van Kesteren]

Letting a top-level site adjust the control flow of an embedded site is generally not a good idea. This has also been removed from XMLHttpRequest.

[Anne van Kesteren]

Actually, there is something implemented. Maybe that needs to be removed.

[Anne van Kesteren]

*** This bug has been marked as a duplicate of bug 202098 ***