1973458 - Pref cleanup: Enforce `security_disallow_privilegedabout_remote_script_loads` by default and remove pref

Status: NEW

(Core :: DOM: Security, enhancement, P3)

Comment 1

[Frederik Braun [:freddy] (OOO until August 18th)]

Attachment: Bug 1973458 - Replace security_disallow_privilegedabout_remote_script_loads with finer graind check r?tschuster

Comment 2

[Frederik Braun [:freddy] (OOO until August 18th)]

Attachment: WIP: Bug 1973458 - some logging to make it easier --- SKIP

Depends on D254657

Comment 3

[Frederik Braun [:freddy] (OOO until August 18th)]

Looks like this pref was used incorrectly, e.g.,

nsresult nsContentSecurityManager::CheckAllowLoadInPrivilegedAboutContext(
    nsIChannel* aChannel) {
  // bail out if check is disabled
  if (StaticPrefs::security_disallow_privilegedabout_remote_script_loads()) {
    return NS_OK;
  }
// ... actual permission checks

The pref currently being true results in the whole block of checks skipped with an early return. The code line should have been if (!StaticPrefs... instead.

I am running into some test failures when the pref is removed, see https://treeherder.mozilla.org/jobs?repo=try&revision=a3c77d8d28001272d848b59d9816c233e4eefd15

Will keep poking at this, but not sure if that's something I can commit to finish.