Add support for AD users to hbactest command

How this works:
  1. When a trusted domain user is tested, AD GC is searched
     for the user entry Distinguished Name
  2. The user entry is then read from AD GC and its SID and SIDs
     of all its assigned groups (tokenGroups attribute) are retrieved
  3. The SIDs are then used to search IPA LDAP database to find
     all external groups which have any of these SIDs as external
     members
  4. All these groups having these groups as direct or indirect
     members are added to hbactest allowing it to perform the search

LIMITATIONS:
- only Trusted Admins group members can use this function as it
  uses secret for IPA-Trusted domain link
- List of group SIDs does not contain group memberships outside
  of the trusted domain

https://fedorahosted.org/freeipa/ticket/2997

ipaserver/dcerpc.py

@@ -275,6 +275,62 @@ class DomainValidator(object):
             raise errors.ValidationError(name=_('trusted domain object'),
                error= _('Trusted domain did not return a valid SID for the object'))
 
+    def get_trusted_domain_user_and_groups(self, object_name):
+        """
+        Returns a tuple with user SID and a list of SIDs of all groups he is
+        a member of.
+
+        LIMITATIONS:
+            - only Trusted Admins group members can use this function as it
+              uses secret for IPA-Trusted domain link
+            - List of group SIDs does not contain group memberships outside
+              of the trusted domain
+        """
+        components = normalize_name(object_name)
+        domain = components.get('domain')
+        flatname = components.get('flatname')
+        name = components.get('name')
+
+        is_valid_sid = is_sid_valid(object_name)
+        if is_valid_sid:
+            # Find a trusted domain for the SID
+            domain = self.get_domain_by_sid(object_name)
+            # Now search a trusted domain for a user with this SID
+            attrs = ['cn']
+            filter = '(&(objectClass=user)(objectSid=%(sid)s))' \
+                    % dict(sid=object_name)
+            try:
+                entries = self.get_trusted_domain_objects(domain=domain, filter=filter,
+                        attrs=attrs, scope=_ldap.SCOPE_SUBTREE)
+            except errors.NotFound:
+                raise errors.NotFound(reason=_('trusted domain user not found'))
+            user_dn = entries[0][0]
+        elif domain or flatname:
+            attrs = ['cn']
+            filter = '(&(sAMAccountName=%(name)s)(objectClass=user))' \
+                    % dict(name=name)
+            try:
+                entries = self.get_trusted_domain_objects(domain,
+                        flatname, filter, attrs, _ldap.SCOPE_SUBTREE)
+            except errors.NotFound:
+                raise errors.NotFound(reason=_('trusted domain user not found'))
+            user_dn = entries[0][0]
+        else:
+            # No domain or realm specified, ambiguous search
+            raise errors.ValidationError(name=_('trusted domain object'),
+                   error= _('Ambiguous search, user domain was not specified'))
+
+        # Get SIDs of user object and it's groups
+        # tokenGroups attribute must be read with a scope BASE for a known user
+        # distinguished name to avoid search error
+        attrs = ['objectSID', 'tokenGroups']
+        filter = "(objectClass=user)"
+        entries = self.get_trusted_domain_objects(domain,
+            flatname, filter, attrs, _ldap.SCOPE_BASE, user_dn)
+        object_sid = self.__sid_to_str(entries[0][1]['objectSid'][0])
+        group_sids = [self.__sid_to_str(sid) for sid in entries[0][1]['tokenGroups']]
+        return (object_sid, group_sids)
+
     def __sid_to_str(self, sid):
         """
         Converts binary SID to string representation