One-way trust is the default now, use 'trust add --two-way ' to
force bidirectional trust
https://fedorahosted.org/freeipa/ticket/4959
In case of one-way trust we cannot authenticate using cross-realm TGT
against an AD DC. We have to use trusted domain object from within AD
domain and access to this object is limited to avoid compromising the whole
trust configuration.
Instead, IPA framework can call out to oddjob daemon and ask it to
run the script which can have access to the TDO object. This script
(com.redhat.idm.trust-fetch-domains) is using cifs/ipa.master principal
to retrieve TDO object credentials from IPA LDAP if needed and then
authenticate against AD DCs using the TDO object credentials.
The script pulls the trust topology out of AD DCs and updates IPA LDAP
store. Then IPA framework can pick the updated data from the IPA LDAP
under normal access conditions.
Part of https://fedorahosted.org/freeipa/ticket/4546
Reviewed-By: Tomas Babej <tbabej@redhat.com>