[tor-dev] #3600 tech doc

Tom Ritter tom at ritter.vg
Fri Jan 18 21:19:00 UTC 2019

On Fri, 18 Jan 2019 at 21:00, Richard Pospesel <richard at torproject.org> wrote:
> The Double-Keyed Redirect Cookies + 'Domain Promotion' tries to fix this
> multiple/hidden session problem by promoting the cookies of double-keyed
> websites to first-party status in the case where the originating domain is
> positively identified as solely a redirect. In the gogle.com -> google.com
> scenario, if Tor Browser could identify that gogle.com is used solely to
> redirect to google.com, then we could take the double-keyed gogle.com|google.com
> cookies and move them into the google.com bucket and eliminate the double
> session.

How would we detect this?

Let's say hypothetically (I haven't checked) gogle.com does not set
any cookies; and just sends a 301 permanent redirect.  We then perform
the upgrade from gogle.com|google.com to google.com

If we turn it on its head: google.com decides to redirect you to
tracker342451345.google.com with a 301 (and setting no cookies.) We
upgrade google.com|tracker342451345.google.com to
tracker342451345.google.com and do so for as long as your session is
Does this enabling a tracking vector? I don't think so; couldn't
identify one - but it feels like there might be something here...


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