cups-pk-helper makes system-config-printer asking for a password when adding a new printer

It seems you have cups-pk-helper installed. This hasn't been integrated into Ubuntu yet (we are about to), so until this is done, please remove the package again.

Thanks for your report!

pitti, that's it. thank you.

I removed cups-pk-helper and it works correctly again.

Moving to cups-pk-helper ...

Current status:

system-config-printer continues to work correctly if cups-pk-helper is not installed.

If cups-pk-helper is installed, the password dialog appears. Choosing a user with system admin privileges and entering his password makes system-config-printer working normally. "Cancel" on the dialog makes system-config-printer not being able to do administrative tasks with CUPS, even listing available printers (equivalent of "lpinfo -m") does not work. If one SSHes into the machine from a remote box and starts system-config-printer, the password dialog does not appear and system-config-printer has no admin access to CUPS, the user has no chance to authenticate.

What I expect is that if the caller of system-config-printer is in the "lpadmin" group (or root), no password dialog should appear and all admin access to CUPS should be possible. If system-config-printer is called by another user, the password dialog should appear and admin access should be granted if the user who logs in is either root, or in the "lpadmin" group, or a user who can do root tasks in Ubuntu via "sudo" (like the first user). This should work independent whether the user is logged in via SSH or locally.

Currently, cups-pk-helper is recommended by the gnome-shell package which has made it getting installed with one of recent updates.

Why does gnome-shell recommend cups-pk-helper? We especially need to take into account that we have hidden away the new printer setup tool of GNOME completely in Ubuntu. Should we perhaps drop the Recommends?

Generally, system-config-printer should work with cups-pk-helper. cups-pk-helper needs to be configured/fixed so that it supports the "lpadmin" group (and also users logged in via SSH).

If cups-pk-helper cannot be fixed for Oneiric, we need to let cups-pk-helper and system-config-printer conflict, which would suppress the fulfilling of the "Recommends: cups-pk-helper" in gnome-shell when system-config-printer is installed. If we do so, in which package the conflict should be defined? cups-pk-helper or system-config-printer?

For Oneiric we will apply a simple patch to system-config-printer to drop the PolicyKit support. This way system-config-printer will continue to behave like in Natty, also with cups-pk-helper being installed.

This is only a temporary solution. After Oneiric we will do improvements on PolicyKit and or cups-pk-helper to implement an easy-to-use PolicyKit-based authentication in system-config-printer.

This bug was fixed in the package system-config-printer - 1.3.6+20110831-0ubuntu4

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system-config-printer (1.3.6+20110831-0ubuntu4) oneiric; urgency=low

  * debian/patches/27_disable-policy-kit-support.patch: Disable the support
    for PolicyKit, as it leads to a password prompt dialog when doing any
    administrative action, even if the calling user is in the "lpadmin"
    group (LP: #807261). Note that this is a temporary solution for
    Oneiric only.
 -- Till Kamppeter <email address hidden> Mon, 12 Sep 2011 15:41:24 +0200

See bug 847896 for the work on a real fix to be done by doing changes on PolicyKit.