(In reply to Jonathan Kew (:jfkthame) from comment #3)
(In reply to Bob Owen (:bobowen) from comment #2)
(In reply to Bobby Holley (:bholley) from comment #1)
Is this something that we could also turn off for content processes, or is it only for utility processes?
I'm hoping we can turn it off for all sandboxed processes, chromium appear to.
jfkthame - I think we only load fonts actually installed on the system on Windows. Does that sound correct?
Almost. We ship an emoji font with the browser (Twemoji Mozilla), and rely on this on Win7 as the system doesn't ship with any color-emoji support. On Win10 we recently stopped loading it by default (bug 1686274), as Segoe UI Emoji provides most of the same characters (with a different design), though we have a pref that can re-enable it. (Note that we've already had bug reports as a result of switching it off -- Segoe UI Emoji doesn't have support for the country-flag emoji -- so it appears users do notice.)
This blocking is win10 only, so we might be OK.
Assuming the way we do web fonts still works (for DirectWrite, I guess the GDI method will be stymied by win32k lockdown either way), I wonder if we could we use that, if we do need to go back to loading this.
I believe the Tor browser also relies on shipping a collection of fonts with the browser, and making these available. So they might need to be able to override this.
Ah OK, I remember something about them limiting the fonts that could be used, but I didn't realise they shipped them/some of them.
Sure enough I can see 5 fonts on top of the emoji one in a Tor browser installation.
Do we know exactly what this option means? Offhand I didn't find a clear explanation of it. Does it apply to DirectWrite APIs or only GDI?
Yeah, the documentation is detail-lite.
I'll have to experiment, but my guess is that is will allow loading from
%WINDDIR%\Fonts\ and probably from
Not sure if it will affect DirectWrite as well as GDI. It doesn't say specifically, although if it is the same mechanism as , then that page seems to suggest it might be just GDI. Again I'll have to try it out.