Add support for external group members

When using ipaExternalGroup/ipaExternalMember attributes it is
possible to add group members which don't exist in IPA database.
This is primarily is required for AD trusts support and therefore
validation is accepting only secure identifier (SID) format.

https://fedorahosted.org/freeipa/ticket/2664

11 files changed, 358 insertions, 29 deletions

diff --git a/API.txt b/API.txt
index 5cdbc79b0..daaa14025 100644
--- a/API.txt
+++ b/API.txt
@@ -1208,13 +1208,14 @@ output: Output('total', <type 'int'>, None)
 output: Output('count', <type 'int'>, None)
 output: Output('summary', (<type 'unicode'>, <type 'NoneType'>), None)
 command: group_add
-args: 1,8,3
+args: 1,9,3
 arg: Str('cn', attribute=True, cli_name='group_name', maxlength=255, multivalue=False, pattern='^[a-zA-Z0-9_.][a-zA-Z0-9_.-]{0,252}[a-zA-Z0-9_.$-]?$', primary_key=True, required=True)
 option: Str('description', attribute=True, cli_name='desc', multivalue=False, required=True)
 option: Int('gidnumber', attribute=True, cli_name='gid', minvalue=1, multivalue=False, required=False)
 option: Str('setattr*', cli_name='setattr', exclude='webui')
 option: Str('addattr*', cli_name='addattr', exclude='webui')
 option: Flag('nonposix', autofill=True, cli_name='nonposix', default=False)
+option: Flag('external', autofill=True, cli_name='external', default=False)
 option: Flag('all', autofill=True, cli_name='all', default=False, exclude='webui')
 option: Flag('raw', autofill=True, cli_name='raw', default=False, exclude='webui')
 option: Str('version?', exclude='webui')
@@ -1222,8 +1223,9 @@ output: Output('summary', (<type 'unicode'>, <type 'NoneType'>), None)
 output: Entry('result', <type 'dict'>, Gettext('A dictionary representing an LDAP entry', domain='ipa', localedir=None))
 output: Output('value', <type 'unicode'>, None)
 command: group_add_member
-args: 1,5,3
+args: 1,6,3
 arg: Str('cn', attribute=True, cli_name='group_name', maxlength=255, multivalue=False, pattern='^[a-zA-Z0-9_.][a-zA-Z0-9_.-]{0,252}[a-zA-Z0-9_.$-]?$', primary_key=True, query=True, required=True)
+option: Str('ipaexternalmember*', cli_name='external', csv=True)
 option: Flag('all', autofill=True, cli_name='all', default=False, exclude='webui')
 option: Flag('raw', autofill=True, cli_name='raw', default=False, exclude='webui')
 option: Str('version?', exclude='webui')
@@ -1277,7 +1279,7 @@ output: ListOfEntries('result', (<type 'list'>, <type 'tuple'>), Gettext('A list
 output: Output('count', <type 'int'>, None)
 output: Output('truncated', <type 'bool'>, None)
 command: group_mod
-args: 1,11,3
+args: 1,12,3
 arg: Str('cn', attribute=True, cli_name='group_name', maxlength=255, multivalue=False, pattern='^[a-zA-Z0-9_.][a-zA-Z0-9_.-]{0,252}[a-zA-Z0-9_.$-]?$', primary_key=True, query=True, required=True)
 option: Str('description', attribute=True, autofill=False, cli_name='desc', multivalue=False, required=False)
 option: Int('gidnumber', attribute=True, autofill=False, cli_name='gid', minvalue=1, multivalue=False, required=False)
@@ -1286,6 +1288,7 @@ option: Str('addattr*', cli_name='addattr', exclude='webui')
 option: Str('delattr*', cli_name='delattr', exclude='webui')
 option: Flag('rights', autofill=True, default=False)
 option: Flag('posix', autofill=True, cli_name='posix', default=False)
+option: Flag('external', autofill=True, cli_name='external', default=False)
 option: Flag('all', autofill=True, cli_name='all', default=False, exclude='webui')
 option: Flag('raw', autofill=True, cli_name='raw', default=False, exclude='webui')
 option: Str('version?', exclude='webui')
@@ -1294,8 +1297,9 @@ output: Output('summary', (<type 'unicode'>, <type 'NoneType'>), None)
 output: Entry('result', <type 'dict'>, Gettext('A dictionary representing an LDAP entry', domain='ipa', localedir=None))
 output: Output('value', <type 'unicode'>, None)
 command: group_remove_member
-args: 1,5,3
+args: 1,6,3
 arg: Str('cn', attribute=True, cli_name='group_name', maxlength=255, multivalue=False, pattern='^[a-zA-Z0-9_.][a-zA-Z0-9_.-]{0,252}[a-zA-Z0-9_.$-]?$', primary_key=True, query=True, required=True)
+option: Str('ipaexternalmember*', cli_name='external', csv=True)
 option: Flag('all', autofill=True, cli_name='all', default=False, exclude='webui')
 option: Flag('raw', autofill=True, cli_name='raw', default=False, exclude='webui')
 option: Str('version?', exclude='webui')
diff --git a/ipalib/errors.py b/ipalib/errors.py
index 407d9f7db..c25560b8e 100644
--- a/ipalib/errors.py
+++ b/ipalib/errors.py
@@ -1277,6 +1277,56 @@ class SingleMatchExpected(ExecutionError):
     format = _('The search criteria was not specific enough. Expected 1 and found %(found)d.')
 
 
+class AlreadyExternalGroup(ExecutionError):
+    """
+    **4028** Raised when a group is already an external member group
+
+    For example:
+
+    >>> raise AlreadyExternalGroup
+    Traceback (most recent call last):
+      ...
+    AlreadyExternalGroup: This group already allows external members
+
+    """
+
+    errno = 4028
+    format = _('This group already allows external members')
+
+class ExternalGroupViolation(ExecutionError):
+    """
+    **4029** Raised when a group is already an external member group
+             and an attempt is made to use it as posix group
+
+    For example:
+
+    >>> raise ExternalGroupViolation
+    Traceback (most recent call last):
+      ...
+    ExternalGroupViolation: This group cannot be posix because it is external
+
+    """
+
+    errno = 4029
+    format = _('This group cannot be posix because it is external')
+
+class PosixGroupViolation(ExecutionError):
+    """
+    **4030** Raised when a group is already a posix group
+             and cannot be converted to external
+
+    For example:
+
+    >>> raise PosixGroupViolation
+    Traceback (most recent call last):
+      ...
+    PosixGroupViolation: This is already a posix group and cannot be converted to external one
+
+    """
+
+    errno = 4030
+    format = _('This is already a posix group and cannot be converted to external one')
+
 class BuiltinError(ExecutionError):
     """
     **4100** Base class for builtin execution errors (*4100 - 4199*).
diff --git a/ipalib/plugins/baseldap.py b/ipalib/plugins/baseldap.py
index 475222a6a..b841435fd 100644
--- a/ipalib/plugins/baseldap.py
+++ b/ipalib/plugins/baseldap.py
@@ -362,23 +362,29 @@ def add_external_post_callback(memberattr, membertype, externalattr, ldap, compl
     externalattr is one of externaluser,
     """
     completed_external = 0
+    normalize = options.get('external_callback_normalize', True)
     # Sift through the failures. We assume that these are all
     # entries that aren't stored in IPA, aka external entries.
     if memberattr in failed and membertype in failed[memberattr]:
         (dn, entry_attrs_) = ldap.get_entry(dn, [externalattr])
         members = entry_attrs.get(memberattr, [])
         external_entries = entry_attrs_.get(externalattr, [])
+        lc_external_entries = set(e.lower() for e in external_entries)
         failed_entries = []
         for entry in failed[memberattr][membertype]:
             membername = entry[0].lower()
             member_dn = api.Object[membertype].get_dn(membername)
-            if membername not in external_entries and \
-              member_dn not in members:
+            if (membername not in lc_external_entries and
+                member_dn not in members):
                 # Not an IPA entry, assume external
-                external_entries.append(membername)
+                if normalize:
+                    external_entries.append(membername)
+                else:
+                    external_entries.append(entry[0])
+                lc_external_entries.add(membername)
                 completed_external += 1
-            elif membername in external_entries and \
-              member_dn not in members:
+            elif (membername in lc_external_entries and
+               member_dn not in members):
                 # Already an external member, reset the error message
                 msg = unicode(errors.AlreadyGroupMember().message)
                 newerror = (entry[0], msg)
@@ -409,8 +415,11 @@ def remove_external_post_callback(memberattr, membertype, externalattr, ldap, co
         completed_external = 0
         for entry in failed[memberattr][membertype]:
             membername = entry[0].lower()
-            if membername in external_entries:
-                external_entries.remove(membername)
+            if membername in external_entries or entry[0] in external_entries:
+                try:
+                    external_entries.remove(membername)
+                except ValueError:
+                    external_entries.remove(entry[0])
                 completed_external += 1
             else:
                 failed_entries.append(membername)
diff --git a/ipalib/plugins/group.py b/ipalib/plugins/group.py
index 65657363a..74bea1700 100644
--- a/ipalib/plugins/group.py
+++ b/ipalib/plugins/group.py
@@ -22,6 +22,12 @@ from ipalib import api
 from ipalib import Int, Str
 from ipalib.plugins.baseldap import *
 from ipalib import _, ngettext
+if api.env.in_server and api.env.context in ['lite', 'server']:
+    try:
+        import ipaserver.dcerpc
+        _dcerpc_bindings_installed = True
+    except Exception, e:
+        _dcerpc_bindings_installed = False
 
 __doc__ = _("""
 Groups of users
@@ -83,11 +89,11 @@ class group(LDAPObject):
     object_name_plural = _('groups')
     object_class = ['ipausergroup']
     object_class_config = 'ipagroupobjectclasses'
-    possible_objectclasses = ['posixGroup', 'mepManagedEntry']
+    possible_objectclasses = ['posixGroup', 'mepManagedEntry', 'ipaExternalGroup']
     search_attributes_config = 'ipagroupsearchfields'
     default_attributes = [
         'cn', 'description', 'gidnumber', 'member', 'memberof',
-        'memberindirect', 'memberofindirect',
+        'memberindirect', 'memberofindirect', 'ipaexternalmember',
     ]
     uuid_attribute = 'ipauniqueid'
     attribute_members = {
@@ -139,10 +145,22 @@ class group_add(LDAPCreate):
              doc=_('Create as a non-POSIX group'),
              default=False,
         ),
+        Flag('external',
+             cli_name='external',
+             doc=_('Allow adding external non-IPA members from trusted domains'),
+             default=False,
+        ),
     )
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
-        if not options['nonposix']:
+        # As both 'external' and 'nonposix' options have default= set for
+        # them, they will always be present in options dict, thus we can
+        # safely reference the values
+        if options['external']:
+            entry_attrs['objectclass'].append('ipaexternalgroup')
+            if 'gidnumber' in options:
+                raise errors.RequirementError(name='gid')
+        elif not options['nonposix']:
             entry_attrs['objectclass'].append('posixgroup')
             if not 'gidnumber' in options:
                 entry_attrs['gidnumber'] = 999
@@ -194,11 +212,18 @@ class group_mod(LDAPUpdate):
              cli_name='posix',
              doc=_('change to a POSIX group'),
         ),
+        Flag('external',
+             cli_name='external',
+             doc=_('change to support external non-IPA members from trusted domains'),
+             default=False,
+        ),
     )
 
     def pre_callback(self, ldap, dn, entry_attrs, *keys, **options):
-        if options['posix'] or 'gidnumber' in options:
+        if ('posix' in options and options['posix']) or 'gidnumber' in options:
             (dn, old_entry_attrs) = ldap.get_entry(dn, ['objectclass'])
+            if 'ipaexternalgroup' in old_entry_attrs['objectclass']:
+                raise errors.ExternalGroupViolation()
             if 'posixgroup' in old_entry_attrs['objectclass']:
                 if options['posix']:
                     raise errors.AlreadyPosixGroup()
@@ -207,6 +232,15 @@ class group_mod(LDAPUpdate):
                 entry_attrs['objectclass'] = old_entry_attrs['objectclass']
                 if not 'gidnumber' in options:
                     entry_attrs['gidnumber'] = 999
+        if options['external']:
+            (dn, old_entry_attrs) = ldap.get_entry(dn, ['objectclass'])
+            if 'posixgroup' in old_entry_attrs['objectclass']:
+                raise errors.PosixGroupViolation()
+            if 'ipaexternalgroup' in old_entry_attrs['objectclass']:
+                raise errors.AlreadyExternalGroup()
+            else:
+                old_entry_attrs['objectclass'].append('ipaexternalgroup')
+                entry_attrs['objectclass'] = old_entry_attrs['objectclass']
         # Can't check for this in a validator because we lack context
         if 'gidnumber' in options and options['gidnumber'] is None:
             raise errors.RequirementError(name='gid')
@@ -274,12 +308,64 @@ api.register(group_show)
 class group_add_member(LDAPAddMember):
     __doc__ = _('Add members to a group.')
 
+    takes_options = (
+        Str('ipaexternalmember*',
+            cli_name='external',
+            label=_('External member'),
+            doc=_('comma-separated SIDs of members of a trusted domain'),
+            csv=True,
+            flags=['no_create', 'no_update', 'no_search'],
+        ),
+    )
+
+    def post_callback(self, ldap, completed, failed, dn, entry_attrs, *keys, **options):
+        result = (completed, dn)
+        if 'ipaexternalmember' in options:
+            if not _dcerpc_bindings_installed:
+                raise errors.NotFound(name=_('AD Trust'),
+                      reason=_('''Cannot perform external member validation without Samba 4 support installed.
+                                  Make sure you have installed server-trust-ad sub-package of IPA on the server'''))
+            domain_validator = ipaserver.dcerpc.DomainValidator(self.api)
+            if not domain_validator.is_configured():
+                raise errors.NotFound(name=_('AD Trust setup'),
+                      reason=_('''Cannot perform join operation without own domain configured.
+                                  Make sure you have run ipa-adtrust-install on the IPA server first'''))
+            sids = []
+            failed_sids = []
+            for sid in options['ipaexternalmember']:
+                if domain_validator.is_trusted_sid_valid(sid):
+                    sids.append(sid)
+                else:
+                    failed_sids.append((sid, 'Not a trusted domain SID'))
+            if len(sids) == 0:
+                raise errors.ValidationError(name=_('external member'),
+                                             error=_('values are not recognized as valid SIDs from trusted domain'))
+            restore = []
+            if 'member' in failed and 'group' in failed['member']:
+                restore = failed['member']['group']
+            failed['member']['group'] = list((id,id) for id in sids)
+            result = add_external_post_callback('member', 'group', 'ipaexternalmember',
+                                                ldap, completed, failed, dn, entry_attrs,
+                                                keys, options, external_callback_normalize=False)
+            failed['member']['group'] = restore + failed_sids
+        return result
+
 api.register(group_add_member)
 
 
 class group_remove_member(LDAPRemoveMember):
     __doc__ = _('Remove members from a group.')
 
+    takes_options = (
+        Str('ipaexternalmember*',
+            cli_name='external',
+            label=_('External member'),
+            doc=_('comma-separated SIDs of members of a trusted domain'),
+            csv=True,
+            flags=['no_create', 'no_update', 'no_search'],
+        ),
+    )
+
     def pre_callback(self, ldap, dn, found, not_found, *keys, **options):
         if keys[0] == protected_group_name:
             result = api.Command.group_show(protected_group_name)
@@ -290,6 +376,20 @@ class group_remove_member(LDAPRemoveMember):
                     label=_(u'group'), container=protected_group_name)
         return dn
 
+    def post_callback(self, ldap, completed, failed, dn, entry_attrs, *keys, **options):
+        result = (completed, dn)
+        if 'ipaexternalmember' in options:
+            sids = options['ipaexternalmember']
+            restore = list()
+            if 'member' in failed and 'group' in failed['member']:
+                restore = failed['member']['group']
+            failed['member']['group'] = list((id,id) for id in sids)
+            result = remove_external_post_callback('member', 'group', 'ipaexternalmember',
+                                                ldap, completed, failed, dn, entry_attrs,
+                                                keys, options)
+            failed['member']['group'] = restore
+        return result
+
 api.register(group_remove_member)
 
 
diff --git a/ipalib/plugins/trust.py b/ipalib/plugins/trust.py
index 71ca23aba..40bd93e65 100644
--- a/ipalib/plugins/trust.py
+++ b/ipalib/plugins/trust.py
@@ -171,6 +171,10 @@ class trust_add(LDAPCreate):
             realm_server = options['realm_server']
 
         trustinstance = ipaserver.dcerpc.TrustDomainJoins(self.api)
+        if not trustinstance.configured:
+            raise errors.NotFound(name=_('AD Trust setup'),
+                  reason=_('''Cannot perform join operation without own domain configured.
+                              Make sure you have run ipa-adtrust-install on the IPA server first'''))
 
         # 1. Full access to the remote domain. Use admin credentials and
         # generate random trustdom password to do work on both sides
diff --git a/ipaserver/dcerpc.py b/ipaserver/dcerpc.py
index 3bc8b63af..07e40c2d3 100644
--- a/ipaserver/dcerpc.py
+++ b/ipaserver/dcerpc.py
@@ -58,6 +58,79 @@ class ExtendedDNControl(_ldap.controls.RequestControl):
     def encodeControlValue(self):
         return '0\x03\x02\x01\x01'
 
+class DomainValidator(object):
+    ATTR_FLATNAME = 'ipantflatname'
+    ATTR_SID = 'ipantsecurityidentifier'
+    ATTR_TRUSTED_SID = 'ipanttrusteddomainsid'
+
+    def __init__(self, api):
+        self.api = api
+        self.ldap = self.api.Backend.ldap2
+        self.domain = None
+        self.flatname = None
+        self.dn = None
+        self.sid = None
+        self._domains = None
+
+    def is_configured(self):
+        cn_trust_local = DN(('cn', self.api.env.domain), self.api.env.container_cifsdomains, self.api.env.basedn)
+        try:
+            (dn, entry_attrs) = self.ldap.get_entry(unicode(cn_trust_local), [self.ATTR_FLATNAME, self.ATTR_SID])
+            self.flatname = entry_attrs[self.ATTR_FLATNAME][0]
+            self.sid = entry_attrs[self.ATTR_SID][0]
+            self.dn = dn
+            self.domain = self.api.env.domain
+        except errors.NotFound, e:
+            return False
+        return True
+
+    def get_trusted_domains(self):
+        cn_trust = DN(('cn', 'ad'), self.api.env.container_trusts, self.api.env.basedn)
+        try:
+            search_kw = {'objectClass': 'ipaNTTrustedDomain'}
+            filter = self.ldap.make_filter(search_kw, rules=self.ldap.MATCH_ALL)
+            (entries, truncated) = self.ldap.find_entries(filter=filter, base_dn=unicode(cn_trust),
+                                                          attrs_list=[self.ATTR_TRUSTED_SID, 'dn'])
+
+            return entries
+        except errors.NotFound, e:
+            return []
+
+    def is_trusted_sid_valid(self, sid):
+        if not self.domain:
+            # our domain is not configured or self.is_configured() never run
+            # reject SIDs as we can't check correctness of them
+            return False
+        # Parse sid string to see if it is really in a SID format
+        try:
+            test_sid = security.dom_sid(sid)
+        except TypeError:
+            return False
+        (dom, sid_rid) = test_sid.split()
+        sid_dom = str(dom)
+        # Now we have domain prefix of the sid as sid_dom string and can
+        # analyze it against known prefixes
+        if sid_dom.find(security.SID_NT_AUTHORITY) != 0:
+            # Ignore any potential SIDs that are not S-1-5-*
+            return False
+        if sid_dom.find(self.sid) == 0:
+            # A SID from our own domain cannot be treated as trusted domain's SID
+            return False
+        # At this point we have SID_NT_AUTHORITY family SID and really need to
+        # check it against prefixes of domain SIDs we trust to
+        if not self._domains:
+            self._domains = self.get_trusted_domains()
+        if len(self._domains) == 0:
+            # Our domain is configured but no trusted domains are configured
+            # This means we can't check the correctness of a trusted domain SIDs
+            return False
+        # We have non-zero list of trusted domains and have to go through them
+        # one by one and check their sids as prefixes
+        for (dn, domaininfo) in self._domains:
+            if sid_dom.find(domaininfo[self.ATTR_TRUSTED_SID][0]) == 0:
+                return True
+        return False
+
 class TrustDomainInstance(object):
 
     def __init__(self, hostname, creds=None):
@@ -247,20 +320,18 @@ class TrustDomainInstance(object):
         self._pipe.CreateTrustedDomainEx2(self._policy_handle, info, self.auth_info, security.SEC_STD_DELETE)
 
 class TrustDomainJoins(object):
-    ATTR_FLATNAME = 'ipantflatname'
-
     def __init__(self, api):
         self.api = api
         self.local_domain = None
         self.remote_domain = None
 
-        self.ldap = self.api.Backend.ldap2
-        cn_trust_local = DN(('cn', self.api.env.domain), self.api.env.container_cifsdomains, self.api.env.basedn)
-        (dn, entry_attrs) = self.ldap.get_entry(unicode(cn_trust_local), [self.ATTR_FLATNAME])
-        self.local_flatname = entry_attrs[self.ATTR_FLATNAME][0]
-        self.local_dn = dn
+        domain_validator = DomainValidator(api)
+        self.configured = domain_validator.is_configured()
 
-        self.__populate_local_domain()
+        if self.configured:
+            self.local_flatname = domain_validator.flatname
+            self.local_dn = domain_validator.dn
+            self.__populate_local_domain()
 
     def __populate_local_domain(self):
         # Initialize local domain info using kerberos only
@@ -308,6 +379,9 @@ class TrustDomainJoins(object):
         self.remote_domain = rd
 
     def join_ad_full_credentials(self, realm, realm_server, realm_admin, realm_passwd):
+        if not self.configured:
+            return None
+
         self.__populate_remote_domain(realm, realm_server, realm_admin, realm_passwd)
         if not self.remote_domain.read_only:
             trustdom_pass = samba.generate_random_password(128, 128)
@@ -317,6 +391,9 @@ class TrustDomainJoins(object):
         return None
 
     def join_ad_ipa_half(self, realm, realm_server, trustdom_passwd):
+        if not self.configured:
+            return None
+
         self.__populate_remote_domain(realm, realm_server, realm_passwd=None)
         self.local_domain.establish_trust(self.remote_domain, trustdom_passwd)
         return dict(local=self.local_domain, remote=self.remote_domain)
diff --git a/tests/test_cmdline/test_cli.py b/tests/test_cmdline/test_cli.py
index d961f8725..06c6124bb 100644
--- a/tests/test_cmdline/test_cli.py
+++ b/tests/test_cmdline/test_cli.py
@@ -66,6 +66,7 @@ class TestCLIParsing(object):
             cn=u'tgroup1',
             description=u'Test group',
             nonposix=False,
+            external=False,
             raw=False,
             all=False,
             version=API_VERSION)
@@ -88,6 +89,7 @@ class TestCLIParsing(object):
             cn=u'tgroup1',
             description=u'Test group',
             nonposix=True,
+            external=False,
             raw=False,
             all=False,
             version=API_VERSION)
@@ -99,6 +101,7 @@ class TestCLIParsing(object):
             description=u'Test group',
             gidnumber=u'1234',
             nonposix=False,
+            external=False,
             raw=False,
             all=False,
             version=API_VERSION)
@@ -109,6 +112,7 @@ class TestCLIParsing(object):
                 cn=u'tgroup1',
                 description=u'Test group',
                 nonposix=False,
+                external=False,
                 raw=False,
                 all=False,
                 version=API_VERSION)
diff --git a/tests/test_xmlrpc/objectclasses.py b/tests/test_xmlrpc/objectclasses.py
index 4bb2b3510..a173bbe5c 100644
--- a/tests/test_xmlrpc/objectclasses.py
+++ b/tests/test_xmlrpc/objectclasses.py
@@ -45,6 +45,8 @@ group = [
     u'ipaobject',
 ]
 
+externalgroup = group + [u'ipaexternalgroup']
+
 host = [
     u'ipasshhost',
     u'ipaSshGroupOfPubKeys',
diff --git a/tests/test_xmlrpc/test_group_plugin.py b/tests/test_xmlrpc/test_group_plugin.py
index 9597992c5..08cf74185 100644
--- a/tests/test_xmlrpc/test_group_plugin.py
+++ b/tests/test_xmlrpc/test_group_plugin.py
@@ -28,11 +28,18 @@ from ipalib.dn import *
 
 group1 = u'testgroup1'
 group2 = u'testgroup2'
+group3 = u'testgroup3'
 renamedgroup1 = u'testgroup'
 user1 = u'tuser1'
 
 invalidgroup1=u'+tgroup1'
 
+# When adding external SID member to a group we can't test
+# it fully due to possibly missing Samba 4 python bindings
+# and/or not configured AD trusts. Thus, we'll use incorrect
+# SID value to merely test that proper exceptions are raised
+external_sid1=u'S-1-1-123456-789-1'
+
 def get_group_dn(cn):
     return DN(('cn', cn), api.env.container_group, api.env.basedn)
 
@@ -40,6 +47,7 @@ class test_group(Declarative):
     cleanup_commands = [
         ('group_del', [group1], {}),
         ('group_del', [group2], {}),
+        ('group_del', [group3], {}),
         ('user_del', [user1], {}),
     ]
 
@@ -373,6 +381,63 @@ class test_group(Declarative):
             ),
         ),
 
+        ###############
+        # test external SID members for group3:
+        dict(
+            desc='Create external %r' % group3,
+            command=(
+                'group_add', [group3], dict(description=u'Test desc 3',external=True)
+            ),
+            expected=dict(
+                value=group3,
+                summary=u'Added group "testgroup3"',
+                result=dict(
+                    cn=[group3],
+                    description=[u'Test desc 3'],
+                    objectclass=objectclasses.externalgroup,
+                    ipauniqueid=[fuzzy_uuid],
+                    dn=lambda x: DN(x) == get_group_dn(group3),
+                ),
+            ),
+        ),
+
+
+        dict(
+            desc='Convert posix group %r to support external membership' % (group2),
+            command=(
+                'group_mod', [group2], dict(external=True)
+            ),
+            expected=errors.PosixGroupViolation(),
+        ),
+
+
+        dict(
+            desc='Convert external members group %r to posix' % (group3),
+            command=(
+                'group_mod', [group3], dict(posix=True)
+            ),
+            expected=errors.ExternalGroupViolation(),
+        ),
+
+
+        dict(
+            desc='Add external member %r to %r' % (external_sid1, group3),
+            command=(
+                'group_add_member', [group3], dict(ipaexternalmember=external_sid1)
+            ),
+            expected=lambda x, output: type(x) == errors.ValidationError or type(x) == errors.NotFound,
+        ),
+
+
+        dict(
+            desc='Remove group %r with external membership' % (group3),
+            command=('group_del', [group3], {}),
+            expected=dict(
+                result=dict(failed=u''),
+                value=group3,
+                summary=u'Deleted group "testgroup3"',
+            ),
+        ),
 
 
         ###############
diff --git a/tests/test_xmlrpc/test_user_plugin.py b/tests/test_xmlrpc/test_user_plugin.py
index 355a4cbbb..b257a90a3 100644
--- a/tests/test_xmlrpc/test_user_plugin.py
+++ b/tests/test_xmlrpc/test_user_plugin.py
@@ -1059,7 +1059,7 @@ class test_user(Declarative):
             command=(
                 'config_mod', [], dict(ipahomesrootdir=u'/other-home'),
             ),
-            expected=lambda x: True,
+            expected=lambda x, output: x is None,
         ),
 
         dict(
@@ -1107,7 +1107,7 @@ class test_user(Declarative):
             command=(
                 'config_mod', [], dict(ipahomesrootdir=u'/home'),
             ),
-            expected=lambda x: True,
+            expected=lambda x, output: x is None,
         ),
 
         dict(
@@ -1125,7 +1125,7 @@ class test_user(Declarative):
             command=(
                 'config_mod', [], dict(ipadefaultloginshell=u'/usr/bin/ipython'),
             ),
-            expected=lambda x: True,
+            expected=lambda x, output: x is None,
         ),
 
         dict(
@@ -1172,7 +1172,7 @@ class test_user(Declarative):
             command=(
                 'config_mod', [], dict(ipadefaultloginshell=u'/bin/sh'),
             ),
-            expected=lambda x: True,
+            expected=lambda x, output: x is None,
         ),
 
         dict(
@@ -1245,7 +1245,7 @@ class test_user(Declarative):
             command=(
                 'config_mod', [], dict(ipadefaultprimarygroup=group1),
             ),
-            expected=lambda x: True,
+            expected=lambda x, output: x is None,
         ),
 
         dict(
@@ -1328,7 +1328,7 @@ class test_user(Declarative):
             command=(
                 'config_mod', [], dict(ipadefaultprimarygroup=u'ipausers'),
             ),
-            expected=lambda x: True,
+            expected=lambda x, output: x is None,
         ),
 
         dict(
diff --git a/tests/test_xmlrpc/xmlrpc_test.py b/tests/test_xmlrpc/xmlrpc_test.py
index c279107b3..cfba35fc5 100644
--- a/tests/test_xmlrpc/xmlrpc_test.py
+++ b/tests/test_xmlrpc/xmlrpc_test.py
@@ -260,6 +260,8 @@ class Declarative(XMLRPC_test):
             raise nose.SkipTest('%r not in api.Command' % cmd)
         if isinstance(expected, errors.PublicError):
             self.check_exception(nice, cmd, args, options, expected)
+        elif hasattr(expected, '__call__'):
+            self.check_callable(nice, cmd, args, options, expected)
         else:
             self.check_output(nice, cmd, args, options, expected, extra_check)
 
@@ -285,6 +287,18 @@ class Declarative(XMLRPC_test):
         # For now just compare the strings
         assert_deepequal(expected.strerror, e.strerror)
 
+    def check_callable(self, nice, cmd, args, options, expected):
+        output = dict()
+        e = None
+        try:
+            output = api.Command[cmd](*args, **options)
+        except StandardError, e:
+           pass
+        if not expected(e, output):
+            raise AssertionError(
+                UNEXPECTED % (cmd, args, options, e.__class__.__name__, e)
+            )
+
     def check_output(self, nice, cmd, args, options, expected, extra_check):
         got = api.Command[cmd](*args, **options)
         assert_deepequal(expected, got, nice)