How can I add object classes and other attributes to an account using the
a value of an attribute already present in the account? What I would like
to do is to extend an account with those attributes for linux
authentication( posixAccount, shadowAccount, etc) based on an attribute
that will indicate the user should have those attributes. I may attempt to
use provisioning in the mix.

Can I use a loopback driver for that? If so, where do I put the rules and
what are the things I need to pay attention to? I noticed the loopback
driver configuration in Designer has to be done from scratch and I have
never done that.