Non-existent home directory entry in /etc/passwd

[Patrick Goetz]

This bug applies to both Ubuntu 18.04 and Ubuntu 20.04, the two distros I've checked.

This is likely a packaging error. The cups-pk-helper user appears in /etc/passwd as:

cups-pk-helper:x:111:118:user for cups-pk-helper service,,,:/home/cups-pk-helper:/usr/sbin/nologin

Of course there is no directory /home/cups-pk-helper. This appears innocuous, but can cause problems for users that have, say autofs mounted home directories. To cite one example, the python virtual environment anaconda trolls through /etc/passwd looking for environments in /home/USER. This triggers autofs to try and mount /home/cups-pk--helper, which doesn't exist, causing the automounter to hang under certain circumstances. In, for example, Arch linux, this entry would appear as the considerably more sensible

cups-pk-helper:x:111:118:user for cups-pk-helper service,,,:/:/usr/sbin/nologin

While an edge case in the current compute environment, this is also a very easy fix. Don't reference non-existent directories. Many Ubuntu packages make this packaging error when creating local users with non-existent home directories; e.g. syslog.