1420234 - The privacy.resistFingerprinting flag interferes with the JS Date object

Status: RESOLVED DUPLICATE of bug 1364261

(Core :: JavaScript Engine, defect)

Description

[Pomax]

By setting the new privacy.resistFingerprinting flag in about:config to true, JavaScript is no longer able to tell which locale it is running in, and so defaults to UTC time, which for the fast majority of FF users means that websites that rely on correct date information become wildly wrong. Most notably this means services like gmail, which rely on Date to tell the user when emails were sent/received etc, but can also affect things like news filtering, which will can discard data due to timestamps being "the wrong time", with a gap that can be up to 14 hours wide.

It's probably worth not automatically tying locale blanking to the "resistFingerprinting" flag, but either making that a separate flag (e.g. privacy.resistFingerprinting.hideLocale) or taking it out of the fingerprinting as Date will still report information when used for fingerprinting purposes, it'll just return a different, stable-across-sessions, string (making it just as usable as when it had the correct locale information).

Comment 1

[André Bargull [:anba]]

Dup of bug 1364261?

Comment 2

[Pomax]

Close enough to it, it seems.