When trust is established, ipasam module creates a number of objects in LDAP
to represent the trust information. Among them, for one-way trust we create
a principal named IPA$@AD where IPA is a NetBIOS (flat) name of the IPA forest
and AD is a realm of the trusted Active Directory forest root domain.

This principal is then used by SSSD on IPA masters to authenticate against
trusted Active Directory domain controllers and retrieve information about
user and group identities.

FreeIPA also uses this principal's credentials to retrieve domain topology.

The access to the keys of the principal should be well-protected. We only
allow to retrieve the keytab for it for members of cn=adtrust agents group.
This group is populated with host/ and cifs/ principals from IPA masters.

Starting with FreeIPA 4.2 the group will also have host/ principals of IPA masters
where no ipa-adtrust-install was run. To add them, run ipa-adtrust-install
on the master which will be configured to be a domain controller (e.g.
run Samba with ipasam), and specify --add-agents option to trigger activation
of the interactive mode to specify which IPA masters to enable.

Fixes https://fedorahosted.org/freeipa/ticket/4962
Part of fixes for https://fedorahosted.org/freeipa/ticket/4546

Reviewed-By: Tomas Babej <tbabej@redhat.com>

1. Samba project renamed libpdb to libsamba-passdb
   https://bugzilla.samba.org/show_bug.cgi?id=10355

2. With interface version 24, Samba removed uid_to_sid()/gid_to_sid()
   from the PASSDB interface and united them as id_to_sid().

Make sure FreeIPA ipa_sam code supports new and old versions of
the PASSDB API.

https://fedorahosted.org/freeipa/ticket/4778

Reviewed-By: Sumit Bose <sbose@redhat.com>

https://fedorahosted.org/freeipa/ticket/4713

Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>

Add idmap_cache calls to ipa-sam to prevent huge numbers of LDAP calls to the
directory service for gid/uid<->sid resolution.

Additionally, this patch further reduces number of queries by:
 - fast fail on uidNumber=0 which doesn't exist in FreeIPA,
 - return fallback group correctly when looking up user primary group as is
   done during init,
 - checking for group objectclass in case insensitive way

Patch by Jason Woods <devel@jasonwoods.me.uk>

Reviewed-by: Alexander Bokovoy <abokovoy@redhat.com>

https://fedorahosted.org/freeipa/ticket/4234
and
https://bugzilla.redhat.com/show_bug.cgi?id=1073829
https://bugzilla.redhat.com/show_bug.cgi?id=1074314

Reviewed-By: Sumit Bose <sbose@redhat.com>

LDAP protocol doesn't allow deleting non-leaf entries. One needs to
remove all leaves first before removing the tree node.

https://fedorahosted.org/freeipa/ticket/4126

https://fedorahosted.org/freeipa/ticket/3896

https://fedorahosted.org/freeipa/ticket/3795

We don't store trust type, attributes, and direction for subdomains
of the existing trust. Since trust is always forest level, these parameters
can be added as defaults when they are missing.

We store Kerberos realm configuration in cn=REALM,cn=kerberos,$SUFFIX.
Along other configuration options, this container has list of default
supported encryption types, in krbDefaultEncSaltTypes.

Fetch krbDefaultEncSaltTypes value on ipa-sam initialization and convert
discovered list to the mask of supported encryption types according to
security.idl from Samba:
        typedef [public,bitmap32bit] bitmap {
                KERB_ENCTYPE_DES_CBC_CRC             = 0x00000001,
                KERB_ENCTYPE_DES_CBC_MD5             = 0x00000002,
                KERB_ENCTYPE_RC4_HMAC_MD5            = 0x00000004,
                KERB_ENCTYPE_AES128_CTS_HMAC_SHA1_96 = 0x00000008,
                KERB_ENCTYPE_AES256_CTS_HMAC_SHA1_96 = 0x00000010
        } kerb_EncTypes;

Part of https://fedorahosted.org/freeipa/ticket/3898

We used to handle some of code paths to free memory allocated by the LDAP library
but there are few more unhandled. In addition, search result wasn't freed on successful
initialization, leaking for long time.

https://fedorahosted.org/freeipa/ticket/3913