»NONEXISTENT« and »PREVENT_NO_AUTH« during update on Debian

[JMLatemby 3]

Hi there, during "dpkg -i emby-server-deb_4.7.6.0_amd64.deb" on Debian updating a running emby server 4.6.4.0 installation, the following warning messages are issued:

dpkg -i emby-server-deb_4.7.6.0_amd64.deb
(Lese Datenbank ... 62781 Dateien und Verzeichnisse sind derzeit installiert.)
Vorbereitung zum Entpacken von emby-server-deb_4.7.6.0_amd64.deb ...
Removed "/etc/systemd/system/multi-user.target.wants/emby-server.service".
Entpacken von emby-server (4.7.6.0) über (4.6.4.0) ...
emby-server (4.7.6.0) wird eingerichtet ...
Neue Version der Konfigurationsdatei /etc/firewalld/services/emby-server.xml wird installiert ...
Neue Version der Konfigurationsdatei /etc/init/emby-server.conf wird installiert ...
Konfigurationsfehler - Element »NONEXISTENT« unbekannt (Administrator verständigen).
Konfigurationsfehler - Element »PREVENT_NO_AUTH« unbekannt (Administrator verständigen).
usermod: Keine Änderungen
Konfigurationsfehler - Element »NONEXISTENT« unbekannt (Administrator verständigen).
Konfigurationsfehler - Element »PREVENT_NO_AUTH« unbekannt (Administrator verständigen).
Konfigurationsfehler - Element »NONEXISTENT« unbekannt (Administrator verständigen).
Konfigurationsfehler - Element »PREVENT_NO_AUTH« unbekannt (Administrator verständigen).
Created symlink /etc/systemd/system/multi-user.target.wants/emby-server.service → /lib/systemd/system/emby-server.service.
Trigger für libc-bin (2.34-4) werden verarbeitet ...

User definitions for user "emby":

cat /etc/passwd | grep ^emby
emby:x:998:998:Emby Server:/var/lib/emby:/usr/sbin/nologin

Also somewhat surprised about new configuration files "/etc/firewalld/services/emby-server.xml" and "/etc/init/emby-server.conf" were created.

My emby server is based on Debian Sid (Bookworm, V12 Testing, Rolling Release), Kernel Linux 5.18.0-4-amd64, SMP Debian 5.18.16-1 (2022-08-10).

Thanks in advance for any advice.

Edited August 30, 2022 by JMLatemby

[alucryd 216]

This is what we run as postinstall:

getent group emby > /dev/null 2>&1 || groupadd -r emby
getent passwd emby > /dev/null 2>&1 && usermod -c 'Emby Server' -g emby -d /var/lib/emby -m -s /usr/sbin/nologin emby
getent passwd emby > /dev/null 2>&1 || (useradd -r -c 'Emby Server' -g emby -d /var/lib/emby -m -s /usr/sbin/nologin emby && passwd -l emby > /dev/null)
getent group video > /dev/null 2>&1 && usermod -aG video emby
getent group render > /dev/null 2>&1 && usermod -aG render emby
if [ -x "$(which systemctl)" ]; then
  systemctl daemon-reload
  systemctl enable emby-server || true
  systemctl start emby-server || true
else
  service emby-server start
fi

Nothing too fancy, can you run these lines as root, see if you get the same errors?

About the new files, I don't speak german but it seems they are new versions of these files, not new files. Which is still weird because they haven't been touched in 5 years. Did you modify any of them in any capacity?

[JMLatemby 3]

Hi @alucryd, these following three commands generate the said error messages, two each:

getent passwd emby > /dev/null 2>&1 && usermod -c 'Emby Server' -g emby -d /var/lib/emby -m -s /usr/sbin/nologin emby
getent group video > /dev/null 2>&1 && usermod -aG video emby
getent group render > /dev/null 2>&1 && usermod -aG render emby

Regarding the added files, both have a timestamp from August 22, 2017, both are the only files in the respective directories and I do not use Init or Firewalld, the last one is not installed at all.

[alucryd 216]

Do you have the getent command on your system? Do you have the video and render groups in /etc/group?

The 2 files are harmless, if you don't use init or firewalld they just won't be used.

[JMLatemby 3]

Yes, both available:

root@xyz:~# getent group render video
render:x:107:emby
video:x:44:peter,emby

root@xyz:~# grep "render\|video" /etc/group
video:x:44:peter,emby
render:x:107:emby
root@xyz:~#

Regarding the two configuration files, in my opinion they were not created in version 4.6.4.0 at least.

Edited August 31, 2022 by JMLatemby

[JMLatemby 3]

I have now done some research and possibly these messages come from the /etc/login.defs file

root@xyz:~# find /etc -type f -exec grep -H NONEXISTENT {} \;
/etc/login.defs:NONEXISTENT     /nonexistent

root@xyz:~# find /etc -type f -exec grep -H PREVENT_NO_AUTH {} \;
/etc/login.defs:PREVENT_NO_AUTH superuser

which contains the following entries:

#
# The pwck(8) utility emits a warning for any system account with a home
# directory that does not exist.  Some system accounts intentionally do
# not have a home directory.  Such accounts may have this string as
# their home directory in /etc/passwd to avoid a spurious warning.
#
NONEXISTENT     /nonexistent

#
# Prevents an empty password field to be interpreted as "no authentication
# required".
# Set to "yes" to prevent for all accounts
# Set to "superuser" to prevent for UID 0 / root (default)
# Set to "no" to not prevent for any account (dangerous, historical default)
PREVENT_NO_AUTH superuser

No idea where what has changed and what kind of impact this has, but I did not get these messages in previous installations for sure.

Edited August 31, 2022 by JMLatemby

[alucryd 216]

I can assure you the files have been present for at least the last 5 years, including in 4.6.4.0 

As for the messages, that's the first time I hear about pwck. `/var/lib/emby` is automatically created, that's what the `-m` is for, unless you deleted it you should not get a warning. As for empty passwords, `passwd -l` with an empty password has been the standard way of creating system accounts for decades, and even then you seem to be set to check superuser only, and emby is hardly superuser, so it doesn't make sense that you're getting a warning.

That makes 3 things that shouldn't have happened, there must be something wrong with your system, I guess it wouldn't hurt to start fresh, I don't know what it is, and what the implications are.

Edited September 1, 2022 by alucryd

[JMLatemby 3]

Thanks for the explanatory notes, @alucryd. Very appreciated!

Directory /var/lib/emby is there, so no problem here. On my server, when I invoke pwck without any arguments, the following messages are shown:

root@xyz:~# pwck
Konfigurationsfehler - Element »NONEXISTENT« unbekannt (Administrator verständigen).
Konfigurationsfehler - Element »PREVENT_NO_AUTH« unbekannt (Administrator verständigen).
Benutzer »lp«: Verzeichnis »/var/spool/lpd« existiert nicht.
Benutzer »news«: Verzeichnis »/var/spool/news« existiert nicht.
Benutzer »uucp«: Verzeichnis »/var/spool/uucp« existiert nicht.
Benutzer »list«: Verzeichnis »/var/list« existiert nicht.
Benutzer »irc«: Verzeichnis »/run/ircd« existiert nicht.
Benutzer »gnats«: Verzeichnis »/var/lib/gnats« existiert nicht.
Benutzer »nobody«: Verzeichnis »/nonexistent« existiert nicht.
Benutzer »_apt«: Verzeichnis »/nonexistent« existiert nicht.
pwck: Keine Änderungen
root@xyz:~#

So it seems obvious to me now that the messages aren't related to the emby installation. I have reported this behavior in the corresponding Debian Shadow tree:
pwck - Element »NONEXISTENT« and »PREVENT_NO_AUTH« unknown

Regarding the two files, you are right, they have always been there, but I never noticed them, firstly because I don't use them, and secondly, because no corresponding messages seem to have been issued about them in previous installations. Here is the terminal output from my former Emby Server V4.6.2.0 installation:

root@xyz:~# dpkg -i emby-server-deb_4.6.2.0_amd64.deb
Vormals nicht ausgewähltes Paket emby-server wird gewählt.
(Lese Datenbank ... 61334 Dateien und Verzeichnisse sind derzeit installiert.)
Vorbereitung zum Entpacken von emby-server-deb_4.6.2.0_amd64.deb ...
Entpacken von emby-server (4.6.2.0) ...
emby-server (4.6.2.0) wird eingerichtet ...
useradd: Warning: missing or non-executable shell '/usr/bin/nologin'
Created symlink /etc/systemd/system/multi-user.target.wants/emby-server.service → /lib/systemd/system/emby-server.service.
Trigger für libc-bin (2.31-12) werden verarbeitet ...

Note: At that time, I corrected the during the installation process missing -respectively wrong defined- shell manually afterwards.

Thanks for supporting me here and for the fantastic work of you all in general!

Edited September 2, 2022 by JMLatemby