Bug#1007018: systemd: Creates broken symlink to stub-resolv.conf since v250

[Arnaud Rebillout]

Package: systemd
Version: 250.3-2
Severity: normal
User: devel at kali.org
Usertags: origin-kali

Dear Maintainer,

Since v250, systemd moved the tmpfiles config for /etc/resolv.conf out
of the file tmpfiles.d/etc.conf and inside a new file
tmpfiles.d/systemd-resolve.conf. Cf:
https://github.com/systemd/systemd/commit/b15f6eae

The Debian package does not install tmpfiles.d/etc.conf, however with
this change it now installs the new file
tmpfiles.d/systemd-resolve.conf. One way to see that:

  +--- (debian stable)
  | # dpkg-query -W | grep '^systemd\s'
  | systemd 247.3-6
  | # grep -rn "resolv\.conf" /usr/lib/tmpfiles.d/
  +---

  +--- (debian unstable)
  | # dpkg-query -W | grep '^systemd\s'
  | systemd 250.3-2
  | # grep -rn "resolv\.conf" /usr/lib/tmpfiles.d/
  | /usr/lib/tmpfiles.d/systemd-resolve.conf:10:L! /etc/resolv.conf - - - - ../run/systemd/resolve/stub-resolv.conf
  +---

The consequence of this change is that, on boot, if there's no file
/etc/resolv.conf, systemd creates a symlink /etc/resolv.conf ->
../run/systemd/resolve/stub-resolv.conf. However, since systemd-resolved
is not enabled, it's a dead symlink, and DNS resolution is broken.

Of course, on most systems there's already a file /etc/resolv.conf, so
an upgrade of the systemd package is unlikely to cause an issue. However
the problem manifests itself when building new systems (eg. with debos),
on first boot there is no file /etc/resolv.conf, and this dead symlink
effectively breaks the network.

>From what I see, I have the impression that this new file
tmpfiles.d/systemd-resolve.conf is shipped in the package by mistake,
and should simply be removed from the package?

Best,

  Arnaud