1664056 - about:welcome should only be able to load in the privileged about process

Status: RESOLVED FIXED

(Firefox :: Messaging System, defect, P1)

Description

[Dan Mosedale (:dmosedale, :dmose)]

Nika pointed this out in Element (thanks Nika!)

I presume the consequence of this is that (some of the time? usually?) we have more privileged code running in some random content process, meaning that the attack surface for exploit trampolining from web site holes is larger than it needs to be. Nika, is this the right analysis? Since it's a straightforward fix, is this something we would want to try and uplift into 81? (I don't really have a good sense of the risk of uplifting this fix)

We don't have the remoteTypes attribute set in the JSWINDOWACTORS definition in BrowserGlue.jsm. Nika included a link to where the NewTab code does this correctly:

https://searchfox.org/mozilla-central/rev/8a0745cd346f0cfb89ae71690babbf7bff706113/browser/components/BrowserGlue.jsm#187

Comment 1

[Dan Mosedale (:dmosedale, :dmose)]

Attachment: Bug 1664056 - set about:welcome to always load in the privelegedabout process, r?mconley!

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/8693eaf05cbe
set about:welcome to always load in the privelegedabout process, r=mconley

Comment 3

[Andreea Pavel [:apavel]]

https://hg.mozilla.org/mozilla-central/rev/8693eaf05cbe

Comment 4

[Nika Layzell [:nika] (ni? for response)]

I don't think this sort of thing is worth uplifting, especially considering the regressions it's caused due to CCOV builds not running with a separate privilegedabout process.