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FreeBSD Errata Notice FreeBSD-EN-24:01.tzdata

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FreeBSD-EN-24:01.tzdata                                         Errata Notice
                                                          The FreeBSD Project

Topic:          Timezone database information update

Category:       contrib
Module:         zoneinfo
Announced:      2024-02-14
Affects:        All supported versions of FreeBSD
Corrected:      2024-02-05 00:30:01 UTC (stable/14, 14.0-STABLE)
                2024-02-14 06:21:06 UTC (releng/14.0, 14.0-RELEASE-p5)
                2024-02-05 00:30:42 UTC (stable/13, 13.2-STABLE)
                2024-02-14 06:27:47 UTC (releng/13.2, 13.2-RELEASE-p10)

For general information regarding FreeBSD Errata Notices and Security
Advisories, including descriptions of the fields above, security
branches, and the following sections, please visit

I.   Background

The IANA Time Zone Database (often called tz or zoneinfo) contains code and
data that represent the history of local time for many representative
locations around the globe.  It is updated periodically to reflect changes
made by political bodies to time zone boundaries, UTC offsets, and
daylight-saving rules.

Leap seconds are occasional adjustments added to -- or potentially subtracted
from -- Coordinated Universal Time (UTC).  An authoritative list of leap
second adjustments is maintained by the International Earth Rotation and
Reference Systems Service (IERS).

FreeBSD releases install the IANA Time Zone Database in /usr/share/zoneinfo.
The tzsetup(8) utility allows the user to specify the default local time
zone.  Based on the selected time zone, tzsetup(8) copies one of the files
from /usr/share/zoneinfo to /etc/localtime.  A time zone may also be selected
for an individual process by setting its TZ environment variable to a desired
time zone name.

The latest list of leap seconds at the time of release is installed on FreeBSD
in /var/db/ntpd.leap-seconds.list.  The startup rc(8) scripts of the ntpd(8)
Network Time Protocol implementation included in the FreeBSD base system can
periodically download an updated leap-seconds.list file from configurable
internet sites.

II.  Problem Description

Several changes to future and past timestamps have been recorded in the IANA
Time Zone Database after previous FreeBSD releases were released.  This
affects many users in different parts of the world.  Because of these
changes, the data in the zoneinfo files need to be updated.  If the local
timezone on the running system is affected, tzsetup(8) needs to be run to
update /etc/localtime.

In the default configuration, the ntpd(8) startup script included with FreeBSD
checks for an updated leap-seconds.list on the IETF's web server.  As of 2023,
the IETF no longer distributes a copy of this file.

III. Impact

An incorrect time will be displayed on a system configured to use one of the
affected time zones if the /usr/share/zoneinfo and /etc/localtime files are
not updated, and all applications on the system that rely on the system time,
such as cron(8) and syslog(8), will be affected.

With the default configuration, FreeBSD systems cannot file updates to the
installed leap-seconds.list file.  Since no leap second was introduced at the
end of 2023, the leap-seconds.list file included with all supported FreeBSD
releases is still accurate.  Moreover, ntpd(8) is able to receive updated leap
second information from its peers.  However, a diagnostic warning about an
expired leap-seconds.list is printed at startup.

IV.  Workaround

The system administrator can install an updated version of the IANA Time Zone
Database from the misc/zoneinfo port and run tzsetup(8).

Applications that store and display times in Coordinated Universal Time (UTC)
are not affected.

The ntpd(8) startup script can be configured to download an updated
leap-seconds.list file from IERS with the following rc.conf(5) setting:


Larger sites, or sites without reliable connectivity to the internet, may wish
to point to their locally maintained copy of this file.

V.   Solution

Upgrade your system to a supported FreeBSD stable or release / security
branch (releng) dated after the correction date.

Please note that some third party software, for instance PHP, Ruby, Java,
Perl and Python, may be using different zoneinfo data sources, in such cases
this software must be updated separately.  Software packages that are
installed via binary packages can be upgraded by executing 'pkg upgrade'.

Following the instructions in this Errata Notice will only update the IANA
Time Zone Database installed in /usr/share/zoneinfo.

Perform one of the following:

1) To update your system via a binary patch:

Systems running a RELEASE version of FreeBSD on the amd64 or arm64 platforms,
or the i386 platform on FreeBSD 13, can be updated via the freebsd-update(8)

# freebsd-update fetch
# freebsd-update install

Restart all the affected applications and daemons, or reboot the system.

2) To update your system via a source code patch:

The following patches have been verified to apply to the applicable
FreeBSD release branches.

a) Download the relevant patch from the location below, and verify the
detached PGP signature using your PGP utility.

# fetch
# fetch
# gpg --verify tzdata-2024a.patch.asc

b) Apply the patch.  Execute the following commands as root:

# cd /usr/src
# patch < /path/to/patch

c) Recompile the operating system using buildworld and installworld as
described in <URL:>.

Restart all the affected applications and daemons, or reboot the system.

VI.  Correction details

This issue is corrected as of the corresponding Git commit hash in the
following stable and release branches:

Branch/path                             Hash                     Revision
- -------------------------------------------------------------------------
stable/14/                              26fe22019cb2    stable/14-n266642
releng/14.0/                            a3b7bafd2acc  releng/14.0-n265409
stable/13/                              f4256acec1c9    stable/13-n257384
releng/13.2/                            66bb668fe5f2  releng/13.2-n254660
- -------------------------------------------------------------------------

Run the following command to see which files were modified by a
particular commit:

# git show --stat <commit hash>

Or visit the following URL, replacing NNNNNN with the hash:


To determine the commit count in a working tree (for comparison against
nNNNNNN in the table above), run:

# git rev-list --count --first-parent HEAD

VII. References


The latest revision of this advisory is available at