[Samba] [Solved] A working CUPS authentication now fails without change anything...

[Daniel Carrasco Marín]

2015-05-12 21:28 GMT+02:00 Andrey Repin <anrdaemon at yandex.ru>:

> Greetings, Daniel Carrasco Marín!
>
> >>>  Hi again!!, this time is not for help request as always :P finally
> i've
> >>>> found the solution and I want to share it.
> >>>> The problem was just permissions. If you change the keytab permission
> to
> >>>> 644 it works perfect: chmod 644 /etc/krb5.keytab
> >>>> Anyway I don't understand why the daemons can't read that file when
> are
> >>>> running as root.
> >>>>
> >>>
> >>> Not all daemons are run as root, far from that.
> >>> Most of single-purpose daemons, such as cups, run as their own users.
> >>>
> >>
> >> Yep, this is done for security purposes so that if one process is
> >> compromised, it doesn't have administrative access to the rest of the
> >> system.
> >>
> >> In a similar vein, you don't generally want any process on the machine
> to
> >> have access to some things.  The system kerberos keytab is probably one
> of
> >> those.  If cups is running as it's own user, a better solution would be
> to
> >> either generate a new keytab just for cups, or copy the existing keytab
> and
> >> make it only readable by the cups user.
> >> --
> >> To unsubscribe from this list go to the following URL and read the
> >> instructions:  https://lists.samba.org/mailman/options/samba
> >>
>
> > Yes, for now keytab is compromised.
>
> > Cups calls pam authentication, and pam use winbind then I need to give
> > permissions to winbind daemon but i don't know what account is using that
> > daemon. How i can see it?, because ps aux shows the most as root.
>
> winbind normally have access to Kerberos keytab by default.
> I see no reason why it would not.
>

I don't know why, but winbind was failing (access denied) until i''ve
changed the permissions to 644. I've tried a lot of things and the file was
created by samba but was failing until i've changed the permissions.

Greetings!!


>
> --
> With best regards,
> Andrey Repin
> Tuesday, May 12, 2015 22:28:05
>
> Sorry for my terrible english...
>