[cups] Allow remote printer admin, but not edit config file

[daku8938 at gmx.de]

Hello,

running CUPS 2.2.7 on Ubuntu18 server.

I want members of the lpadmin user group to have full remote access to manage printers, print-jobs and view log files.

But those users shall _not_ be allowed to edit (or even view) the /etc/cups/cupsd.conf file and restart cups.

Here is the /etc/cupsd.conf

<Location />
  # Allow remote administration...
  Order allow,deny
  Allow all
</Location>

<Location /admin>
  AuthType Default
  Require user @SYSTEM
  # Allow remote administration...
  Order allow,deny
  Allow all
</Location>

<Location /admin/conf>
  # Allow remote access to the configuration files...
  Order allow,deny
</Location>

<Location /admin/log>
  AuthType Default
  Require user @SYSTEM
  Order allow,deny
  # Allow remote access to the log files...
  Order allow,deny
  Allow all
</Location>

I would guess the location /admin/conf/ would be the point to disallow editing the cupsd.conf file via web interface.
But editing the cupsd.conf goes via /admin/. So here I disallowed /admin/conf/ but it does not have effect.

So how can I prevent the printer admins from remote editing the cupsd.conf file via web interface and restarting cupsd ?

Thank you