1817701 - No daylight savings with Firefox snap when /etc/localtime is a regular file

Status: RESOLVED FIXED

(Firefox Build System :: Third Party Packaging, defect)

Description

[Tim Starling]

User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/110.0

Steps to reproduce:

In Xubuntu 22.04 I used time-admin to set the timezone to Australia/Sydney. I started Firefox, using the snap version 110.0-3. I noticed that the time reported by the browser was incorrect. It was off by one hour, as if daylight savings time was not in effect.

I installed Firefox nightly but was not able to reproduce the problem. I suspect that it is specific to the snap package.

I discovered that the problem only occurs if /etc/localtime is a regular file. time-admin uses system-tools-backends to set the timezone, which contains the Perl code:

unlink $localtime;  # Important, since it might be a symlink.

&Utils::Report::enter ();
$res = copy ($tz, $localtime);
&Utils::Report::leave ();

Arguably this is the wrong way to update the timezone, since man localtime(5) says that /etc/localtime should be a symlink. But it is old code, with a copyright date of 2000-2001, and is apparently widely used.

To reproduce, make /etc/localtime be a regular file:

sudo rm /etc/localtime
sudo cp /usr/share/zoneinfo/Australia/Sydney /etc/localtime

Start firefox from the snap, and in the console, type

new Date()

Actual results:

Date Mon Feb 20 2023 11:26:19 GMT+1000 (GMT+10:00)

Expected results:

Date Mon Feb 20 2023 12:26:19 GMT+1100 (GMT+11:00)

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Core::Widget: Gtk' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 2

[Tim Starling]

The libc in the container is 2.31-0ubuntu9.9 from the "core20" snap. The libc in the host is 2.35-0ubuntu3.1. When /etc/localtime is a regular file, it is copied into the container and read by libc 2.31. Evidently libc 2.31 has a limited ability to read zoneinfo files made by libc 2.35.

Using a more recent libc would probably fix it.

Comment 3

[Tim Starling]

I proposed a patch for system-tools-backends at https://bugs.launchpad.net/ubuntu/+source/system-tools-backends/+bug/2007806

Comment 4

[BugBot [:suhaib / :marco/ :calixte]]

The severity field is not set for this bug.
:gerard-majax, could you have a look please?

For more information, please visit auto_nag documentation.

Comment 5

[:gerard-majax]

Amin, there's an upstream patch, can you have a look ?

Comment 6

[Tim Starling]

Note that the real upstream is https://system-tools-backends.freedesktop.org/ , which hasn't had a release or a commit to its git repo since 2009. It's not used by Gnome anymore, but it's still used by Xubuntu (Xfce). The Debian package has been updated more recently, with a patch added in 2016. I filed my bug against the Ubuntu package because forcing Firefox users to use Snap is an Ubuntu decision, Debian is not doing that.

Comment 7

[Amin Bandali [:bandali]]

Thanks, the patch has been applied. Though, based on the above descriptions, this issue might be mitigated with our upcoming switch from core20 to core22 for the Firefox snap anyway.

Comment 8

[:gerard-majax]

Thanks all, I'm going to mark this as fixed now since the patch was applied. Please reopen if the issue persists