freeipa/ipaserver/dcerpc.py
Alexander Bokovoy 7269687822 Add verification of the AD trust
Since we only can perform verification when AD admin credentials are available,
report that trust should be verified from the AD side in other cases,
including unsuccessful verification.

Once trust is added, status of it is never stored anywhere.

https://fedorahosted.org/freeipa/ticket/2763
2012-09-17 21:24:38 -04:00

485 lines
20 KiB
Python

# Authors:
# Alexander Bokovoy <abokovoy@redhat.com>
#
# Copyright (C) 2011 Red Hat
# see file 'COPYING' for use and warranty information
#
# Portions (C) Andrew Tridgell, Andrew Bartlett
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
# Make sure we only run this module at the server where samba4-python
# package is installed to avoid issues with unavailable modules
from ipalib.plugins.baseldap import *
from ipalib import api, Str, Password, DefaultFrom, _, ngettext, Object
from ipalib.parameters import Enum
from ipalib import Command
from ipalib import errors
from ipapython import ipautil
from ipapython.ipa_log_manager import *
from ipaserver.install import installutils
import os, string, struct, copy
import uuid
from samba import param
from samba import credentials
from samba.dcerpc import security, lsa, drsblobs, nbt, netlogon
from samba.ndr import ndr_pack
from samba import net
import samba
import random
import ldap as _ldap
from Crypto.Cipher import ARC4
__doc__ = _("""
Classes to manage trust joins using DCE-RPC calls
The code in this module relies heavily on samba4-python package
and Samba4 python bindings.
""")
access_denied_error = errors.ACIError(info=_('CIFS server denied your credentials'))
dcerpc_error_codes = {
-1073741823:
errors.RemoteRetrieveError(reason=_('communication with CIFS server was unsuccessful')),
-1073741790: access_denied_error,
-1073741715: access_denied_error,
-1073741614: access_denied_error,
-1073741603:
errors.ValidationError(name=_('AD domain controller'), error=_('unsupported functional level')),
}
dcerpc_error_messages = {
"NT_STATUS_OBJECT_NAME_NOT_FOUND":
errors.NotFound(reason=_('Cannot find specified domain or server name')),
"NT_STATUS_INVALID_PARAMETER_MIX":
errors.RequirementError(name=_('At least the domain or IP address should be specified')),
}
def assess_dcerpc_exception(num=None,message=None):
"""
Takes error returned by Samba bindings and converts it into
an IPA error class.
"""
if num and num in dcerpc_error_codes:
return dcerpc_error_codes[num]
if message and message in dcerpc_error_messages:
return dcerpc_error_messages[message]
reason = _('''CIFS server communication error: code "%(num)s",
message "%(message)s" (both may be "None")''') % dict(num=num, message=message)
return errors.RemoteRetrieveError(reason=reason)
class ExtendedDNControl(_ldap.controls.RequestControl):
def __init__(self):
self.controlType = "1.2.840.113556.1.4.529"
self.criticality = False
self.integerValue = 1
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(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=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):
self.parm = param.LoadParm()
self.parm.load(os.path.join(ipautil.SHARE_DIR,"smb.conf.empty"))
if len(hostname) > 0:
self.parm.set('netbios name', hostname)
self.creds = creds
self.hostname = hostname
self.info = {}
self._pipe = None
self._policy_handle = None
self.read_only = False
def __gen_lsa_connection(self, binding):
if self.creds is None:
raise errors.RequirementError(name=_('CIFS credentials object'))
try:
result = lsa.lsarpc(binding, self.parm, self.creds)
return result
except RuntimeError, (num, message):
raise assess_dcerpc_exception(num=num, message=message)
def __init_lsa_pipe(self, remote_host):
"""
Try to initialize connection to the LSA pipe at remote host.
This method tries consequently all possible transport options
and selects one that works. See __gen_lsa_bindings() for details.
The actual result may depend on details of existing credentials.
For example, using signing causes NO_SESSION_KEY with Win2K8 and
using kerberos against Samba with signing does not work.
"""
# short-cut: if LSA pipe is initialized, skip completely
if self._pipe:
return
attempts = 0
bindings = self.__gen_lsa_bindings(remote_host)
for binding in bindings:
try:
self._pipe = self.__gen_lsa_connection(binding)
if self._pipe:
break
except errors.ACIError, e:
attempts = attempts + 1
if self._pipe is None and attempts == len(bindings):
raise errors.ACIError(
info=_('CIFS server %(host)s denied your credentials') % dict(host=remote_host))
if self._pipe is None:
raise errors.RemoteRetrieveError(
reason=_('Cannot establish LSA connection to %(host)s. Is CIFS server running?') % dict(host=remote_host))
self.binding = binding
def __gen_lsa_bindings(self, remote_host):
"""
There are multiple transports to issue LSA calls. However, depending on a
system in use they may be blocked by local operating system policies.
Generate all we can use. __init_lsa_pipe() will try them one by one until
there is one working.
We try NCACN_NP before NCACN_IP_TCP and signed sessions before unsigned.
"""
transports = (u'ncacn_np', u'ncacn_ip_tcp')
options = ( u',', u'')
binding_template=lambda x,y,z: u'%s:%s[%s]' % (x, y, z)
return [binding_template(t, remote_host, o) for t in transports for o in options]
def retrieve_anonymously(self, remote_host, discover_srv=False):
"""
When retrieving DC information anonymously, we can't get SID of the domain
"""
netrc = net.Net(creds=self.creds, lp=self.parm)
try:
if discover_srv:
result = netrc.finddc(domain=remote_host, flags=nbt.NBT_SERVER_LDAP | nbt.NBT_SERVER_DS)
else:
result = netrc.finddc(address=remote_host, flags=nbt.NBT_SERVER_LDAP | nbt.NBT_SERVER_DS)
except RuntimeError, e:
raise assess_dcerpc_exception(message=str(e))
if not result:
return False
self.info['name'] = unicode(result.domain_name)
self.info['dns_domain'] = unicode(result.dns_domain)
self.info['dns_forest'] = unicode(result.forest)
self.info['guid'] = unicode(result.domain_uuid)
self.info['dc'] = unicode(result.pdc_dns_name)
# Netlogon response doesn't contain SID of the domain.
# We need to do rootDSE search with LDAP_SERVER_EXTENDED_DN_OID control to reveal the SID
ldap_uri = 'ldap://%s' % (result.pdc_dns_name)
conn = _ldap.initialize(ldap_uri)
conn.set_option(_ldap.OPT_SERVER_CONTROLS, [ExtendedDNControl()])
result = None
try:
(objtype, res) = conn.search_s('', _ldap.SCOPE_BASE)[0]
result = res['defaultNamingContext'][0]
self.info['dns_hostname'] = res['dnsHostName'][0]
except _ldap.LDAPError, e:
root_logger.error(
"LDAP error when connecting to %(host)s: %(error)s" %
dict(host=unicode(result.pdc_name), error=str(e)))
if result:
self.info['sid'] = self.parse_naming_context(result)
return True
def parse_naming_context(self, context):
naming_ref = re.compile('.*<SID=(S-.*)>.*')
return naming_ref.match(context).group(1)
def retrieve(self, remote_host):
self.__init_lsa_pipe(remote_host)
objectAttribute = lsa.ObjectAttribute()
objectAttribute.sec_qos = lsa.QosInfo()
try:
self._policy_handle = self._pipe.OpenPolicy2(u"", objectAttribute, security.SEC_FLAG_MAXIMUM_ALLOWED)
result = self._pipe.QueryInfoPolicy2(self._policy_handle, lsa.LSA_POLICY_INFO_DNS)
except RuntimeError, (num, message):
raise assess_dcerpc_exception(num=num, message=message)
self.info['name'] = unicode(result.name.string)
self.info['dns_domain'] = unicode(result.dns_domain.string)
self.info['dns_forest'] = unicode(result.dns_forest.string)
self.info['guid'] = unicode(result.domain_guid)
self.info['sid'] = unicode(result.sid)
self.info['dc'] = remote_host
def generate_auth(self, trustdom_secret):
def arcfour_encrypt(key, data):
c = ARC4.new(key)
return c.encrypt(data)
def string_to_array(what):
blob = [0] * len(what)
for i in range(len(what)):
blob[i] = ord(what[i])
return blob
password_blob = string_to_array(trustdom_secret.encode('utf-16-le'))
clear_value = drsblobs.AuthInfoClear()
clear_value.size = len(password_blob)
clear_value.password = password_blob
clear_authentication_information = drsblobs.AuthenticationInformation()
clear_authentication_information.LastUpdateTime = samba.unix2nttime(int(time.time()))
clear_authentication_information.AuthType = lsa.TRUST_AUTH_TYPE_CLEAR
clear_authentication_information.AuthInfo = clear_value
authentication_information_array = drsblobs.AuthenticationInformationArray()
authentication_information_array.count = 1
authentication_information_array.array = [clear_authentication_information]
outgoing = drsblobs.trustAuthInOutBlob()
outgoing.count = 1
outgoing.current = authentication_information_array
confounder = [3]*512
for i in range(512):
confounder[i] = random.randint(0, 255)
trustpass = drsblobs.trustDomainPasswords()
trustpass.confounder = confounder
trustpass.outgoing = outgoing
trustpass.incoming = outgoing
trustpass_blob = ndr_pack(trustpass)
encrypted_trustpass = arcfour_encrypt(self._pipe.session_key, trustpass_blob)
auth_blob = lsa.DATA_BUF2()
auth_blob.size = len(encrypted_trustpass)
auth_blob.data = string_to_array(encrypted_trustpass)
auth_info = lsa.TrustDomainInfoAuthInfoInternal()
auth_info.auth_blob = auth_blob
self.auth_info = auth_info
def establish_trust(self, another_domain, trustdom_secret):
"""
Establishes trust between our and another domain
Input: another_domain -- instance of TrustDomainInstance, initialized with #retrieve call
trustdom_secret -- shared secred used for the trust
"""
self.generate_auth(trustdom_secret)
info = lsa.TrustDomainInfoInfoEx()
info.domain_name.string = another_domain.info['dns_domain']
info.netbios_name.string = another_domain.info['name']
info.sid = security.dom_sid(another_domain.info['sid'])
info.trust_direction = lsa.LSA_TRUST_DIRECTION_INBOUND | lsa.LSA_TRUST_DIRECTION_OUTBOUND
info.trust_type = lsa.LSA_TRUST_TYPE_UPLEVEL
info.trust_attributes = lsa.LSA_TRUST_ATTRIBUTE_FOREST_TRANSITIVE | lsa.LSA_TRUST_ATTRIBUTE_USES_RC4_ENCRYPTION
try:
dname = lsa.String()
dname.string = another_domain.info['dns_domain']
res = self._pipe.QueryTrustedDomainInfoByName(self._policy_handle, dname, lsa.LSA_TRUSTED_DOMAIN_INFO_FULL_INFO)
self._pipe.DeleteTrustedDomain(self._policy_handle, res.info_ex.sid)
except RuntimeError, e:
pass
try:
self._pipe.CreateTrustedDomainEx2(self._policy_handle, info, self.auth_info, security.SEC_STD_DELETE)
except RuntimeError, (num, message):
raise assess_dcerpc_exception(num=num, message=message)
def verify_trust(self, another_domain):
def retrieve_netlogon_info_2(domain, function_code, data):
try:
netr_pipe = netlogon.netlogon(domain.binding, domain.parm, domain.creds)
result = netr_pipe.netr_LogonControl2Ex(logon_server=None,
function_code=function_code,
level=2,
data=data
)
return result
except RuntimeError, (num, message):
raise assess_dcerpc_exception(num=num, message=message)
result = retrieve_netlogon_info_2(self,
netlogon.NETLOGON_CONTROL_TC_VERIFY,
another_domain.info['dns_domain'])
if (unicode(result.trusted_dc_name)[2:] == another_domain.info['dc'] and
result.tc_connection_status == (0, 'WERR_OK')):
return True
return False
class TrustDomainJoins(object):
def __init__(self, api):
self.api = api
self.local_domain = None
self.remote_domain = None
domain_validator = DomainValidator(api)
self.configured = domain_validator.is_configured()
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
ld = TrustDomainInstance(self.local_flatname)
ld.creds = credentials.Credentials()
ld.creds.set_kerberos_state(credentials.MUST_USE_KERBEROS)
ld.creds.guess(ld.parm)
ld.creds.set_workstation(ld.hostname)
ld.retrieve(installutils.get_fqdn())
self.local_domain = ld
def __populate_remote_domain(self, realm, realm_server=None, realm_admin=None, realm_passwd=None):
def get_instance(self):
# Fetch data from foreign domain using password only
rd = TrustDomainInstance('')
rd.parm.set('workgroup', self.local_domain.info['name'])
rd.creds = credentials.Credentials()
rd.creds.set_kerberos_state(credentials.DONT_USE_KERBEROS)
rd.creds.guess(rd.parm)
return rd
rd = get_instance(self)
rd.creds.set_anonymous()
rd.creds.set_workstation(self.local_domain.hostname)
if realm_server is None:
rd.retrieve_anonymously(realm, discover_srv=True)
else:
rd.retrieve_anonymously(realm_server, discover_srv=False)
rd.read_only = True
if realm_admin and realm_passwd:
if 'name' in rd.info:
names = realm_admin.split('\\')
if len(names) > 1:
# realm admin is in DOMAIN\user format
# strip DOMAIN part as we'll enforce the one discovered
realm_admin = names[-1]
auth_string = u"%s\%s%%%s" % (rd.info['name'], realm_admin, realm_passwd)
td = get_instance(self)
td.creds.parse_string(auth_string)
td.creds.set_workstation(self.local_domain.hostname)
if realm_server is None:
# we must have rd.info['dns_hostname'] then, part of anonymous discovery
td.retrieve(rd.info['dns_hostname'])
else:
td.retrieve(realm_server)
td.read_only = False
self.remote_domain = td
return
# Otherwise, use anonymously obtained data
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)
self.remote_domain.establish_trust(self.local_domain, trustdom_pass)
self.local_domain.establish_trust(self.remote_domain, trustdom_pass)
result = self.remote_domain.verify_trust(self.local_domain)
return dict(local=self.local_domain, remote=self.remote_domain, verified=result)
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, verified=False)