Add TLS Support for LDAP

Fixes Bug1040115

added several test cases, also provides a full ldap
regression suite. Also added supplemental (simple)
verification for CACERTFILE and CACERTDIR
added a TLS disable option when ldaps URLs are used
and did full regression tests using ldaps URLs
and with TLS
addresses ayoung's comments
addresses dolphm's and Mouad's comments
addresses gyee's doc request and bknudson's comments

Change-Id: I639f2853df0ce5c10ae85b06214b26430d872aca

doc/source/configuration.rst

@@ -1082,3 +1082,25 @@ specified classes in the LDAP module so you can configure them like::
   role_name_attribute      = ou
   role_member_attribute    = roleOccupant
   role_attribute_ignore    =
+
+If you are using a directory server to provide the Identity service,
+it is strongly recommended that you utilize a secure connection from
+Keystone to the directory server.  In addition to supporting ldaps,  Keystone
+also provides Transport Layer Security (TLS) support. There are some
+basic configuration options for enabling TLS, identifying a single
+file or directory that contains certificates for all the Certificate
+Authorities that the Keystone LDAP client will recognize, and declaring
+what checks the client should perform on server certificates.  This
+functionality can easily be configured as follows::
+
+  [ldap]
+  use_tls = True
+  tls_cacertfile = /etc/keystone/ssl/certs/cacert.pem
+  tls_cacertdir = /etc/keystone/ssl/certs/
+  tls_req_cert = demand
+
+A few points worth mentioning regarding the above options.  If both
+tls_cacertfile and tls_cacertdir are set then tls_cacertfile will be
+used and tls_cacertdir is ignored.  Furthermore, valid options for
+tls_req_cert are demand, never, and allow.  These correspond to the
+standard options permitted by the TLS_REQCERT TLS option.

etc/keystone.conf.sample

@@ -212,6 +212,15 @@
 # group_allow_update = True
 # group_allow_delete = True
 
+# ldap TLS options
+# if both tls_cacertfile and tls_cacertdir are set then
+# tls_cacertfile will be used and tls_cacertdir is ignored
+# valid options for tls_req_cert are demand, never, and allow
+# use_tls = False
+# tls_cacertfile =
+# tls_cacertdir =
+# tls_req_cert = demand
+
 [auth]
 methods = password,token
 password = keystone.auth.plugins.password.Password

keystone/common/config.py

@@ -351,6 +351,10 @@ def configure():
     register_bool('domain_allow_delete', group='ldap', default=True)
     register_bool('domain_enabled_emulation', group='ldap', default=False)
     register_str('domain_enabled_emulation_dn', group='ldap', default=None)
+    register_str('tls_cacertfile', group='ldap', default=None)
+    register_str('tls_cacertdir',  group='ldap', default=None)
+    register_bool('use_tls', group='ldap', default=False)
+    register_str('tls_req_cert', group='ldap', default='demand')
 
     # pam
     register_str('url', group='pam', default=None)

keystone/common/ldap/core.py

@@ -14,6 +14,8 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+import os.path
+
 import ldap
 from ldap import filter as ldap_filter
 
@@ -34,6 +36,9 @@ LDAP_DEREF = {'always': ldap.DEREF_ALWAYS,
               'finding': ldap.DEREF_FINDING,
               'never': ldap.DEREF_NEVER,
               'searching': ldap.DEREF_SEARCHING}
+LDAP_TLS_CERTS = {'never': ldap.OPT_X_TLS_NEVER,
+                  'demand': ldap.OPT_X_TLS_DEMAND,
+                  'allow': ldap.OPT_X_TLS_ALLOW}
 
 
 def py2ldap(val):
@@ -75,6 +80,15 @@ def parse_deref(opt):
                          opt) + ', '.join(LDAP_DEREF.keys()))
 
 
+def parse_tls_cert(opt):
+    try:
+        return LDAP_TLS_CERTS[opt]
+    except KeyError:
+        raise ValueError((_('Invalid LDAP tls certs option: %s. '
+                            'Choose one of: ') %
+                         opt) + ', '.join(LDAP_TLS_CERTS.keys()))
+
+
 def ldap_scope(scope):
     try:
         return LDAP_SCOPES[scope]
@@ -106,6 +120,10 @@ class BaseLdap(object):
         self.LDAP_SCOPE = ldap_scope(conf.ldap.query_scope)
         self.alias_dereferencing = parse_deref(conf.ldap.alias_dereferencing)
         self.page_size = conf.ldap.page_size
+        self.use_tls = conf.ldap.use_tls
+        self.tls_cacertfile = conf.ldap.tls_cacertfile
+        self.tls_cacertdir = conf.ldap.tls_cacertdir
+        self.tls_req_cert = parse_tls_cert(conf.ldap.tls_req_cert)
 
         if self.options_name is not None:
             self.suffix = conf.ldap.suffix
@@ -157,7 +175,11 @@ class BaseLdap(object):
         else:
             conn = LdapWrapper(self.LDAP_URL,
                                self.page_size,
-                               alias_dereferencing=self.alias_dereferencing)
+                               alias_dereferencing=self.alias_dereferencing,
+                               use_tls=self.use_tls,
+                               tls_cacertfile=self.tls_cacertfile,
+                               tls_cacertdir=self.tls_cacertdir,
+                               tls_req_cert=self.tls_req_cert)
 
         if user is None:
             user = self.LDAP_USER
@@ -363,13 +385,75 @@ class BaseLdap(object):
 
 
 class LdapWrapper(object):
-    def __init__(self, url, page_size, alias_dereferencing=None):
+    def __init__(self, url, page_size, alias_dereferencing=None,
+                 use_tls=False, tls_cacertfile=None, tls_cacertdir=None,
+                 tls_req_cert='demand'):
         LOG.debug(_("LDAP init: url=%s"), url)
+        LOG.debug(_('LDAP init: use_tls=%(use_tls)s\n'
+                  'tls_cacertfile=%(tls_cacertfile)s\n'
+                  'tls_cacertdir=%(tls_cacertdir)s\n'
+                  'tls_req_cert=%(tls_req_cert)s\n'
+                  'tls_avail=%(tls_avail)s\n') %
+                  {'use_tls': use_tls,
+                   'tls_cacertfile': tls_cacertfile,
+                   'tls_cacertdir': tls_cacertdir,
+                   'tls_req_cert': tls_req_cert,
+                   'tls_avail': ldap.TLS_AVAIL
+                   })
+
+        #NOTE(topol)
+        #for extra debugging uncomment the following line
+        #ldap.set_option(ldap.OPT_DEBUG_LEVEL, 4095)
+
+        using_ldaps = url.lower().startswith("ldaps")
+
+        if use_tls and using_ldaps:
+            raise AssertionError(_('Invalid TLS / LDAPS combination'))
+
+        if use_tls:
+            if not ldap.TLS_AVAIL:
+                raise ValueError(_('Invalid LDAP TLS_AVAIL option: %s. TLS'
+                                   'not available') % ldap.TLS_AVAIL)
+            if tls_cacertfile:
+                #NOTE(topol)
+                #python ldap TLS does not verify CACERTFILE or CACERTDIR
+                #so we add some extra simple sanity check verification
+                #Also, setting these values globally (i.e. on the ldap object)
+                #works but these values are ignored when setting them on the
+                #connection
+                if not os.path.isfile(tls_cacertfile):
+                    raise IOError(_("tls_cacertfile %s not found "
+                                    "or is not a file") %
+                                  tls_cacertfile)
+                ldap.set_option(ldap.OPT_X_TLS_CACERTFILE, tls_cacertfile)
+            elif tls_cacertdir:
+                #NOTE(topol)
+                #python ldap TLS does not verify CACERTFILE or CACERTDIR
+                #so we add some extra simple sanity check verification
+                #Also, setting these values globally (i.e. on the ldap object)
+                #works but these values are ignored when setting them on the
+                #connection
+                if not os.path.isdir(tls_cacertdir):
+                    raise IOError(_("tls_cacertdir %s not found "
+                                    "or is not a directory") %
+                                  tls_cacertdir)
+                ldap.set_option(ldap.OPT_X_TLS_CACERTDIR, tls_cacertdir)
+            if tls_req_cert in LDAP_TLS_CERTS.values():
+                ldap.set_option(ldap.OPT_X_TLS_REQUIRE_CERT, tls_req_cert)
+            else:
+                LOG.debug(_("LDAP TLS: invalid TLS_REQUIRE_CERT Option=%s"),
+                          tls_req_cert)
+
         self.conn = ldap.initialize(url)
+        self.conn.protocol_version = ldap.VERSION3
+
         if alias_dereferencing is not None:
             self.conn.set_option(ldap.OPT_DEREF, alias_dereferencing)
         self.page_size = page_size
 
+        if use_tls:
+            self.conn.start_tls_s()
+
     def simple_bind_s(self, user, password):
         LOG.debug(_("LDAP bind: dn=%s"), user)
         return self.conn.simple_bind_s(user, password)

tests/_ldap_tls_livetest.py

@@ -0,0 +1,118 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright 2013 OpenStack LLC
+# Copyright 2013 IBM Corp.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+import ldap
+import ldap.modlist
+import nose.exc
+import subprocess
+
+from keystone.common import ldap as ldap_common
+from keystone import config
+from keystone import exception
+from keystone.identity.backends import ldap as identity_ldap
+from keystone import identity
+from keystone import test
+
+import default_fixtures
+import _ldap_livetest
+
+
+CONF = config.CONF
+
+
+def create_object(dn, attrs):
+    conn = ldap.initialize(CONF.ldap.url)
+    conn.simple_bind_s(CONF.ldap.user, CONF.ldap.password)
+    ldif = ldap.modlist.addModlist(attrs)
+    conn.add_s(dn, ldif)
+    conn.unbind_s()
+
+
+class LiveTLSLDAPIdentity(_ldap_livetest.LiveLDAPIdentity):
+
+    def _set_config(self):
+        self.config([test.etcdir('keystone.conf.sample'),
+                     test.testsdir('test_overrides.conf'),
+                     test.testsdir('backend_tls_liveldap.conf')])
+
+    def test_tls_certfile_demand_option(self):
+        CONF.ldap.use_tls = True
+        CONF.ldap.tls_cacertdir = None
+        CONF.ldap.tls_req_cert = 'demand'
+        self.identity_api = identity.backends.ldap.Identity()
+
+        user = {'id': 'fake1',
+                'name': 'fake1',
+                'password': 'fakepass1',
+                'tenants': ['bar']}
+        self.identity_api.create_user('fake1', user)
+        user_ref = self.identity_api.get_user('fake1')
+        self.assertEqual(user_ref['id'], 'fake1')
+
+        user['password'] = 'fakepass2'
+        self.identity_api.update_user('fake1', user)
+
+        self.identity_api.delete_user('fake1')
+        self.assertRaises(exception.UserNotFound, self.identity_api.get_user,
+                          'fake1')
+
+    def test_tls_certdir_demand_option(self):
+        CONF.ldap.use_tls = True
+        CONF.ldap.tls_cacertfile = None
+        CONF.ldap.tls_req_cert = 'demand'
+        self.identity_api = identity.backends.ldap.Identity()
+
+        user = {'id': 'fake1',
+                'name': 'fake1',
+                'password': 'fakepass1',
+                'tenants': ['bar']}
+        self.identity_api.create_user('fake1', user)
+        user_ref = self.identity_api.get_user('fake1')
+        self.assertEqual(user_ref['id'], 'fake1')
+
+        user['password'] = 'fakepass2'
+        self.identity_api.update_user('fake1', user)
+
+        self.identity_api.delete_user('fake1')
+        self.assertRaises(exception.UserNotFound, self.identity_api.get_user,
+                          'fake1')
+
+    def test_tls_bad_certfile(self):
+        CONF.ldap.use_tls = True
+        CONF.ldap.tls_req_cert = 'demand'
+        CONF.ldap.tls_cacertfile = '/etc/keystone/ssl/certs/mythicalcert.pem'
+        CONF.ldap.tls_cacertdir = None
+        self.identity_api = identity.backends.ldap.Identity()
+
+        user = {'id': 'fake1',
+                'name': 'fake1',
+                'password': 'fakepass1',
+                'tenants': ['bar']}
+        self.assertRaises(IOError, self.identity_api.create_user, 'fake', user)
+
+    def test_tls_bad_certdir(self):
+        CONF.ldap.use_tls = True
+        CONF.ldap.tls_cacertfile = None
+        CONF.ldap.tls_req_cert = 'demand'
+        CONF.ldap.tls_cacertdir = '/etc/keystone/ssl/mythicalcertdir'
+        self.identity_api = identity.backends.ldap.Identity()
+
+        user = {'id': 'fake1',
+                'name': 'fake1',
+                'password': 'fakepass1',
+                'tenants': ['bar']}
+        self.assertRaises(IOError, self.identity_api.create_user, 'fake', user)

tests/backend_tls_liveldap.conf

@@ -0,0 +1,23 @@
+[ldap]
+url = ldap://
+user = dc=Manager,dc=openstack,dc=org
+password = test
+suffix = dc=openstack,dc=org
+group_tree_dn = ou=UserGroups,dc=openstack,dc=org
+role_tree_dn = ou=Roles,dc=openstack,dc=org
+tenant_tree_dn = ou=Projects,dc=openstack,dc=org
+domain_tree_dn = ou=Domains,dc=openstack,dc=org
+user_tree_dn = ou=Users,dc=openstack,dc=org
+tenant_enabled_emulation = True
+user_enabled_emulation = True
+domain_enabled_emulation = True
+user_mail_attribute = mail
+use_dumb_member = True
+use_tls = True
+tls_cacertfile = /etc/keystone/ssl/certs/cacert.pem
+tls_cacertdir = /etc/keystone/ssl/certs/
+tls_req_cert = demand
+
+[identity]
+driver = keystone.identity.backends.ldap.Identity
+