1462115 - privacy.resistfingerprinting affects the timezone displayed in native file picker dialogs

Status: RESOLVED DUPLICATE of bug 1709867

(Core :: DOM: Security, defect, P3)

Description

[François Marier [:francois]]

Attachment: native-filepicker-gtk3.png

privacy.resistfingerprinting fakes the user timezone to UTC.

That appears to also affect chrome and so the native file picker UI on my Linux machine shows times in UTC instead of local time.

Steps:

0. set privacy.resistfingerprinting to true in about:config
1. create a new file using `touch foobar`
2. attach that file on Bugzilla
3. look at the time next to the `foobar` file

Expected:

File should show the same time as `ls -l foobar`.

Actual:

File on disk is shown in local (UTC-0700) time:

  ~/bugzilla$ ls -l foobar
  -rw-r--r-- 1 francois francois 0 May 16 12:56 foobar

while the GTK3 file picker in Firefox shows `19:56` (see attached screenshot), which is UTC.

Comment 1

[Andrea Marchesini [:baku]]

This happens because we set TZ env to be 'UTC', when resistfingerprinting is enabled.

https://searchfox.org/mozilla-central/rev/5a744713370ec47969595e369fd5125f123e6d24/toolkit/components/resistfingerprinting/nsRFPService.cpp#809

The filepicker dialog uses the same env variable.

Comment 2

[Ethan Tseng [:ethan]]

This issue shall be fixed by bug 1491343, which plans to use some alternative approach to spoof timezone instead of changing the environment variable.