ipa-adtrust-install: configure compatibility tree to serve trusted domain users

Enables  support  for  trusted  domains  users  for old clients through Schema
Compatibility plugin.  SSSD supports trusted domains natively starting with
version 1.9 platform. For platforms that lack SSSD or run older SSSD version
one needs  to  use  this  option.  When  enabled, slapi-nis  package  needs  to
be  installed  and schema-compat-plugin will be configured to provide lookup of
users and groups from trusted domains via SSSD on IPA server. These users and
groups will be available under  cn=users,cn=compat,$SUFFIX  and
cn=groups,cn=compat,$SUFFIX trees.  SSSD will normalize names of users and
groups to lower case.

In  addition  to  providing  these users and groups through the compat tree,
this option enables authentication over LDAP for trusted domain users with DN
under compat tree, i.e. using bind DN uid=administrator@ad.domain,cn=users,cn=compat,$SUFFIX.

This authentication  is related to  PAM  stack  using  'system-auth' PAM
service. If you have disabled HBAC rule 'allow_all', then make sure there is
special service called 'system-auth' created and HBAC rule to allow access to
anyone to this rule on IPA masters is added. Please note that system-auth PAM
service is  not used directly by any other application, therefore it is safe to
create one specifically to support trusted domain users via compatibility path.

https://fedorahosted.org/freeipa/ticket/3567

1 files changed, 23 insertions, 0 deletions

diff --git a/install/tools/man/ipa-adtrust-install.1 b/install/tools/man/ipa-adtrust-install.1
index 38957f3a4..7f0566e13 100644
--- a/install/tools/man/ipa-adtrust-install.1
+++ b/install/tools/man/ipa-adtrust-install.1
@@ -106,6 +106,29 @@ The password of the user with administrative privileges for this IPA server. Wil
 .TP
 The credentials of the admin user will be used to obtain Kerberos ticket before configuring cross-realm trusts support and afterwards, to ensure that the ticket contains MS-PAC information required to actually add a trust with Active Directory domain via 'ipa trust-add --type=ad' command.
 .TP
+\fB\-\-enable\-compat\fR
+Enables support for trusted domains users for old clients through Schema Compatibility plugin.
+SSSD supports trusted domains natively starting with version 1.9. For platforms that
+lack SSSD or run older SSSD version one needs to use this option. When enabled, slapi\-nis package
+needs to be installed and schema\-compat\-plugin will be configured to provide lookup of
+users and groups from trusted domains via SSSD on IPA server. These users and groups will be
+available under \fBcn=users,cn=compat,$SUFFIX\fR and \fBcn=groups,cn=compat,$SUFFIX\fR trees.
+SSSD will normalize names of users and groups to lower case.
+.IP
+In addition to providing these users and groups through the compat tree, this option enables
+authentication over LDAP for trusted domain users with DN under compat tree, i.e. using bind DN
+\fBuid=administrator@ad.domain,cn=users,cn=compat,$SUFFIX\fR.
+.IP
+LDAP authentication performed by the compat tree is done via PAM '\fBsystem\-auth\fR' service.
+This service exists by default on Linux systems and is provided by pam package as /etc/pam.d/system\-auth.
+If your IPA install does not have default HBAC rule 'allow_all' enabled, then make sure
+to define in IPA special service called '\fBsystem\-auth\fR' and create an HBAC
+rule to allow access to anyone to this rule on IPA masters.
+.IP
+As '\fBsystem\-auth\fR' PAM service is not used directly by any other
+application, it is safe to use it for trusted domain users via compatibility
+path.
+.TP
 .SH "EXIT STATUS"
 0 if the installation was successful