Thanks for the background. Let's continue to discuss on the issue. On Tue, Nov 3, 2020 at 12:32 AM Maciej Stachowiak <m...@apple.com> wrote:
> > > On Nov 2, 2020, at 8:56 AM, Yoav Weiss <y...@yoav.ws> wrote: > > Thanks for re-reviewing, Maciej! > > Adding Mike Taylor, who's likely to take a closer look at this. > > On Mon, Nov 2, 2020 at 2:17 AM Maciej Stachowiak <m...@apple.com> wrote: > >> >> I just did a fresh review of that spec and explainer. Thanks for >> addressing many of the previous issues. This addresses many of the >> potential objections. >> >> Here’s the new issues I filed: >> >> https://github.com/WICG/ua-client-hints/issues/141 >> https://github.com/WICG/ua-client-hints/issues/142 >> https://github.com/WICG/ua-client-hints/issues/143 >> https://github.com/WICG/ua-client-hints/issues/144 >> https://github.com/WICG/ua-client-hints/issues/145 >> https://github.com/WICG/ua-client-hints/issues/146 >> https://github.com/WICG/ua-client-hints/issues/147 >> https://github.com/WICG/ua-client-hints/issues/148 >> https://github.com/WICG/ua-client-hints/issues/149 >> https://github.com/WICG/ua-client-hints/issues/150 >> https://github.com/WICG/ua-client-hints/issues/151 >> >> > Thanks for filing those! We'll take a look and respond shortly. > > >> Most of these are minor/editorial, but I think 151 is potentially a >> deal-breaker. I may be misreading the spec, but as written >> getHighEntropyValues seems to give access to all of the high entropy client >> hints to third-party scripts in the first party context, and scripts >> running in third-party iframes, regardless of which ones the site has opted >> into via the relevant HTTP header. >> > > That's indeed the case, as we didn't consider the Client Hints opt-in to > be something that impacts the availability of the JS API. (as it doesn't do > that for other hints) > > > We’re currently deeply skeptical of implementing any of the other client > hints due to their expansion of fingerprinting surface, so I don’t feel > particularly compelled by that precedent. That said, it’s likely the other > client hints have this same problem, where they expose fingerprinting > surface way more widely than they may be intending to. > > That would be a huge problem, as it would grant a lot of active >> fingerprinting surface unnecessarily >> > > We did discuss > <https://github.com/WICG/ua-client-hints/issues/37#issuecomment-576730548> > adding > a Feature Policy (now Permission Policy) to that effect. Would that help > with your concerns? > > > My understanding is that feature policy applies at the frame level, and > therefore could not be used to control what happens when a third-party > script in a first party context calls the API. Even for third-party > iframes, it seems like Feature Policy could only default-deny this JS API > entirely, and would not be able to filter the results down to the set > delegated via HTTP headers (or otherwise). Maybe you intend a feature > policy per individual high entropy hint, but first of all that seems like > overkill, and second, the spec is clearly not written to support such > filtering. > > So no, it would not address the concerns. > > I think the best approach is to limit the hints to those opted into (or, > in case of a third-party frame, delegated). That or remove the script API > entirely. The origin-based delegation model that works well at the HTTP > level is not well aligned with the widespread practice of including > third-party scripts in the top frame. > > The spec does not eve allow denying the request entirely as written. A > non-normative Note suggests that is allowed, but I can’t find any step in > the algorithm that would ever reject the promise. > > > >> (perhaps even expanding beyond what is currently possible with the UA >> string). >> > > Can you expand on that last point? > > > I mean that the client hints might include info that is not in the UA > sting (possibly not at all, or possibly frozen in UA string but could be > unfrozen in the client hints). > > > >> >> Regards, >> Maciej >> >> >> On Oct 27, 2020, at 12:35 AM, Yoav Weiss <y...@yoav.ws> wrote: >> >> Yet-another ping! :) >> >> On Wed, Oct 7, 2020 at 8:23 AM Yoav Weiss <y...@yoav.ws> wrote: >> >>> Friendly ping! :) >>> >>> On Wed, Sep 30, 2020 at 9:29 AM Yoav Weiss <y...@yoav.ws> wrote: >>> >>>> Hi WebKit folks, >>>> >>>> Circling back on the previous discussion >>>> <https://lists.webkit.org/pipermail/webkit-dev/2020-May/031195.html> about >>>> User-Agent ClientHint. The feature was implemented in Chromium and is being >>>> rolled out in Chrome. >>>> >>>> There were some concerns mentioned in the previous thread, that we >>>> believe were since addressed. Would the feature be something that WebKit >>>> would consider shipping? >>>> >>>> Cheers :) >>>> Yoav >>>> >>> _______________________________________________ >> webkit-dev mailing list >> webkit-dev@lists.webkit.org >> https://lists.webkit.org/mailman/listinfo/webkit-dev >> >> >
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