python/samba/drs_utils.py

   1 # DRS utility code
   2 #
   3 # Copyright Andrew Tridgell 2010
   4 # Copyright Andrew Bartlett 2017
   5 #
   6 # This program is free software; you can redistribute it and/or modify
   7 # it under the terms of the GNU General Public License as published by
   8 # the Free Software Foundation; either version 3 of the License, or
   9 # (at your option) any later version.
  10 #
  11 # This program is distributed in the hope that it will be useful,
  12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 # GNU General Public License for more details.
  15 #
  16 # You should have received a copy of the GNU General Public License
  17 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 #
  19
  20 from samba.dcerpc import drsuapi, misc, drsblobs
  21 from samba.net import Net
  22 from samba.ndr import ndr_unpack
  23 from samba import dsdb
  24 from samba import werror
  25 from samba import WERRORError
  26 import samba
  27 import ldb
  28 from samba.dcerpc.drsuapi import (DRSUAPI_ATTID_name,
  29                                   DRSUAPI_SUPPORTED_EXTENSION_GETCHGREQ_V8,
  30                                   DRSUAPI_SUPPORTED_EXTENSION_GETCHGREQ_V10)
  31 import re
  32
  33
  34 class drsException(Exception):
  35     """Base element for drs errors"""
  36
  37     def __init__(self, value):
  38         self.value = value
  39
  40     def __str__(self):
  41         return "drsException: " + self.value
  42
  43
  44 def drsuapi_connect(server, lp, creds, ip=None):
  45     """Make a DRSUAPI connection to the server.
  46
  47     :param server: the name of the server to connect to
  48     :param lp: a samba line parameter object
  49     :param creds: credential used for the connection
  50     :param ip: Forced target server name
  51     :return: A tuple with the drsuapi bind object, the drsuapi handle
  52                 and the supported extensions.
  53     :raise drsException: if the connection fails
  54     """
  55
  56     binding_options = "seal"
  57     if lp.log_level() >= 9:
  58         binding_options += ",print"
  59
  60     # Allow forcing the IP
  61     if ip is not None:
  62         binding_options += f",target_hostname={server}"
  63         binding_string = f"ncacn_ip_tcp:{ip}[{binding_options}]"
  64     else:
  65         binding_string = "ncacn_ip_tcp:%s[%s]" % (server, binding_options)
  66
  67     try:
  68         drsuapiBind = drsuapi.drsuapi(binding_string, lp, creds)
  69         (drsuapiHandle, bindSupportedExtensions) = drs_DsBind(drsuapiBind)
  70     except Exception as e:
  71         raise drsException("DRS connection to %s failed: %s" % (server, e))
  72
  73     return (drsuapiBind, drsuapiHandle, bindSupportedExtensions)
  74
  75
  76 def sendDsReplicaSync(drsuapiBind, drsuapi_handle, source_dsa_guid,
  77                       naming_context, req_option):
  78     """Send DS replica sync request.
  79
  80     :param drsuapiBind: a drsuapi Bind object
  81     :param drsuapi_handle: a drsuapi handle on the drsuapi connection
  82     :param source_dsa_guid: the guid of the source dsa for the replication
  83     :param naming_context: the DN of the naming context to replicate
  84     :param req_options: replication options for the DsReplicaSync call
  85     :raise drsException: if any error occur while sending and receiving the
  86         reply for the dsReplicaSync
  87     """
  88
  89     nc = drsuapi.DsReplicaObjectIdentifier()
  90     nc.dn = naming_context
  91
  92     req1 = drsuapi.DsReplicaSyncRequest1()
  93     req1.naming_context = nc
  94     req1.options = req_option
  95     req1.source_dsa_guid = misc.GUID(source_dsa_guid)
  96
  97     try:
  98         drsuapiBind.DsReplicaSync(drsuapi_handle, 1, req1)
  99     except Exception as estr:
 100         raise drsException("DsReplicaSync failed %s" % estr)
 101
 102
 103 def drs_DsBind(drs):
 104     """make a DsBind call, returning the binding handle"""
 105     bind_info = drsuapi.DsBindInfoCtr()
 106     bind_info.length = 28
 107     bind_info.info = drsuapi.DsBindInfo28()
 108     bind_info.info.supported_extensions |= drsuapi.DRSUAPI_SUPPORTED_EXTENSION_BASE
 109     bind_info.info.supported_extensions |= drsuapi.DRSUAPI_SUPPORTED_EXTENSION_ASYNC_REPLICATION
 110     bind_info.info.supported_extensions |= drsuapi.DRSUAPI_SUPPORTED_EXTENSION_REMOVEAPI
 111     bind_info.info.supported_extensions |= drsuapi.DRSUAPI_SUPPORTED_EXTENSION_MOVEREQ_V2
 112     bind_info.info.supported_extensions |= drsuapi.DRSUAPI_SUPPORTED_EXTENSION_GETCHG_COMPRESS
 113     bind_info.info.supported_extensions |= drsuapi.DRSUAPI_SUPPORTED_EXTENSION_DCINFO_V1
 114     bind_info.info.supported_extensions |= drsuapi.DRSUAPI_SUPPORTED_EXTENSION_RESTORE_USN_OPTIMIZATION
 115     bind_info.info.supported_extensions |= drsuapi.DRSUAPI_SUPPORTED_EXTENSION_KCC_EXECUTE
 116     bind_info.info.supported_extensions |= drsuapi.DRSUAPI_SUPPORTED_EXTENSION_ADDENTRY_V2
 117     bind_info.info.supported_extensions |= drsuapi.DRSUAPI_SUPPORTED_EXTENSION_LINKED_VALUE_REPLICATION
 118     bind_info.info.supported_extensions |= drsuapi.DRSUAPI_SUPPORTED_EXTENSION_DCINFO_V2
 119     bind_info.info.supported_extensions |= drsuapi.DRSUAPI_SUPPORTED_EXTENSION_INSTANCE_TYPE_NOT_REQ_ON_MOD
 120     bind_info.info.supported_extensions |= drsuapi.DRSUAPI_SUPPORTED_EXTENSION_CRYPTO_BIND
 121     bind_info.info.supported_extensions |= drsuapi.DRSUAPI_SUPPORTED_EXTENSION_GET_REPL_INFO
 122     bind_info.info.supported_extensions |= drsuapi.DRSUAPI_SUPPORTED_EXTENSION_STRONG_ENCRYPTION
 123     bind_info.info.supported_extensions |= drsuapi.DRSUAPI_SUPPORTED_EXTENSION_DCINFO_V01
 124     bind_info.info.supported_extensions |= drsuapi.DRSUAPI_SUPPORTED_EXTENSION_TRANSITIVE_MEMBERSHIP
 125     bind_info.info.supported_extensions |= drsuapi.DRSUAPI_SUPPORTED_EXTENSION_ADD_SID_HISTORY
 126     bind_info.info.supported_extensions |= drsuapi.DRSUAPI_SUPPORTED_EXTENSION_POST_BETA3
 127     bind_info.info.supported_extensions |= drsuapi.DRSUAPI_SUPPORTED_EXTENSION_GET_MEMBERSHIPS2
 128     bind_info.info.supported_extensions |= drsuapi.DRSUAPI_SUPPORTED_EXTENSION_GETCHGREQ_V6
 129     bind_info.info.supported_extensions |= drsuapi.DRSUAPI_SUPPORTED_EXTENSION_NONDOMAIN_NCS
 130     bind_info.info.supported_extensions |= drsuapi.DRSUAPI_SUPPORTED_EXTENSION_GETCHGREQ_V8
 131     bind_info.info.supported_extensions |= drsuapi.DRSUAPI_SUPPORTED_EXTENSION_GETCHGREPLY_V5
 132     bind_info.info.supported_extensions |= drsuapi.DRSUAPI_SUPPORTED_EXTENSION_GETCHGREPLY_V6
 133     bind_info.info.supported_extensions |= drsuapi.DRSUAPI_SUPPORTED_EXTENSION_ADDENTRYREPLY_V3
 134     bind_info.info.supported_extensions |= drsuapi.DRSUAPI_SUPPORTED_EXTENSION_GETCHGREPLY_V7
 135     bind_info.info.supported_extensions |= drsuapi.DRSUAPI_SUPPORTED_EXTENSION_VERIFY_OBJECT
 136     (info, handle) = drs.DsBind(misc.GUID(drsuapi.DRSUAPI_DS_BIND_GUID), bind_info)
 137
 138     return (handle, info.info.supported_extensions)
 139
 140
 141 def drs_get_rodc_partial_attribute_set(samdb):
 142     """get a list of attributes for RODC replication"""
 143     partial_attribute_set = drsuapi.DsPartialAttributeSet()
 144     partial_attribute_set.version = 1
 145
 146     attids = []
 147
 148     # the exact list of attids we send is quite critical. Note that
 149     # we do ask for the secret attributes, but set SPECIAL_SECRET_PROCESSING
 150     # to zero them out
 151     schema_dn = samdb.get_schema_basedn()
 152     res = samdb.search(base=schema_dn, scope=ldb.SCOPE_SUBTREE,
 153                        expression="objectClass=attributeSchema",
 154                        attrs=["lDAPDisplayName", "systemFlags",
 155                               "searchFlags"])
 156
 157     for r in res:
 158         ldap_display_name = str(r["lDAPDisplayName"][0])
 159         if "systemFlags" in r:
 160             system_flags      = r["systemFlags"][0]
 161             if (int(system_flags) & (samba.dsdb.DS_FLAG_ATTR_NOT_REPLICATED |
 162                                      samba.dsdb.DS_FLAG_ATTR_IS_CONSTRUCTED)):
 163                 continue
 164         if "searchFlags" in r:
 165             search_flags = r["searchFlags"][0]
 166             if (int(search_flags) & samba.dsdb.SEARCH_FLAG_RODC_ATTRIBUTE):
 167                 continue
 168         attid = samdb.get_attid_from_lDAPDisplayName(ldap_display_name)
 169         attids.append(int(attid))
 170
 171     # the attids do need to be sorted, or windows doesn't return
 172     # all the attributes we need
 173     attids.sort()
 174     partial_attribute_set.attids         = attids
 175     partial_attribute_set.num_attids = len(attids)
 176     return partial_attribute_set
 177
 178
 179 def drs_copy_highwater_mark(hwm, new_hwm):
 180     """
 181     Copies the highwater mark by value, rather than by object reference. (This
 182     avoids lingering talloc references to old GetNCChanges reply messages).
 183     """
 184     hwm.tmp_highest_usn = new_hwm.tmp_highest_usn
 185     hwm.reserved_usn = new_hwm.reserved_usn
 186     hwm.highest_usn = new_hwm.highest_usn
 187
 188
 189 class drs_Replicate(object):
 190     """DRS replication calls"""
 191
 192     def __init__(self, binding_string, lp, creds, samdb, invocation_id):
 193         self.drs = drsuapi.drsuapi(binding_string, lp, creds)
 194         (self.drs_handle, self.supports_ext) = drs_DsBind(self.drs)
 195         self.net = Net(creds=creds, lp=lp)
 196         self.samdb = samdb
 197         if not isinstance(invocation_id, misc.GUID):
 198             raise RuntimeError("Must supply GUID for invocation_id")
 199         if invocation_id == misc.GUID("00000000-0000-0000-0000-000000000000"):
 200             raise RuntimeError("Must not set GUID 00000000-0000-0000-0000-000000000000 as invocation_id")
 201         self.replication_state = self.net.replicate_init(self.samdb, lp, self.drs, invocation_id)
 202         self.more_flags = 0
 203
 204     def _should_retry_with_get_tgt(self, error_code, req):
 205
 206         # If the error indicates we fail to resolve a target object for a
 207         # linked attribute, then we should retry the request with GET_TGT
 208         # (if we support it and haven't already tried that)
 209         supports_ext = self.supports_ext
 210
 211         return (error_code == werror.WERR_DS_DRA_RECYCLED_TARGET and
 212                 supports_ext & DRSUAPI_SUPPORTED_EXTENSION_GETCHGREQ_V10 and
 213                 (req.more_flags & drsuapi.DRSUAPI_DRS_GET_TGT) == 0)
 214
 215     @staticmethod
 216     def _should_calculate_missing_anc_locally(error_code, req):
 217         # If the error indicates we fail to resolve the parent object
 218         # for a new object, then we assume we are replicating from a
 219         # buggy server (Samba 4.5 and earlier) that doesn't really
 220         # understand how to implement GET_ANC
 221
 222         return ((error_code == werror.WERR_DS_DRA_MISSING_PARENT) and
 223                 (req.replica_flags & drsuapi.DRSUAPI_DRS_GET_ANC) != 0)
 224
 225
 226     def _calculate_missing_anc_locally(self, ctr):
 227         self.guids_seen = set()
 228
 229         # walk objects in ctr, add to guid_seen as we see them
 230         # note if an object doesn't have a parent
 231
 232         object_to_check = ctr.first_object
 233
 234         while True:
 235             if object_to_check is None:
 236                 break
 237
 238             self.guids_seen.add(str(object_to_check.object.identifier.guid))
 239
 240             if object_to_check.parent_object_guid is not None \
 241                and object_to_check.parent_object_guid \
 242                != misc.GUID("00000000-0000-0000-0000-000000000000") \
 243                and str(object_to_check.parent_object_guid) not in self.guids_seen:
 244                 obj_dn = ldb.Dn(self.samdb, object_to_check.object.identifier.dn)
 245                 parent_dn = obj_dn.parent()
 246                 print(f"Object {parent_dn} with "
 247                       f"GUID {object_to_check.parent_object_guid} "
 248                       "was not sent by the server in this chunk")
 249
 250             object_to_check = object_to_check.next_object
 251
 252
 253     def process_chunk(self, level, ctr, schema, req_level, req, first_chunk):
 254         """Processes a single chunk of received replication data"""
 255         # pass the replication into the py_net.c python bindings for processing
 256         self.net.replicate_chunk(self.replication_state, level, ctr,
 257                                  schema=schema, req_level=req_level, req=req)
 258
 259     def replicate(self, dn, source_dsa_invocation_id, destination_dsa_guid,
 260                   schema=False, exop=drsuapi.DRSUAPI_EXOP_NONE, rodc=False,
 261                   replica_flags=None, full_sync=True, sync_forced=False, more_flags=0):
 262         """replicate a single DN"""
 263
 264         # setup for a GetNCChanges call
 265         if self.supports_ext & DRSUAPI_SUPPORTED_EXTENSION_GETCHGREQ_V10:
 266             req = drsuapi.DsGetNCChangesRequest10()
 267             req.more_flags = (more_flags | self.more_flags)
 268             req_level = 10
 269         else:
 270             req_level = 8
 271             req = drsuapi.DsGetNCChangesRequest8()
 272
 273         req.destination_dsa_guid = destination_dsa_guid
 274         req.source_dsa_invocation_id = source_dsa_invocation_id
 275         req.naming_context = drsuapi.DsReplicaObjectIdentifier()
 276         req.naming_context.dn = dn
 277
 278         # Default to a full replication if we don't find an upToDatenessVector
 279         udv = None
 280         hwm = drsuapi.DsReplicaHighWaterMark()
 281         hwm.tmp_highest_usn = 0
 282         hwm.reserved_usn = 0
 283         hwm.highest_usn = 0
 284
 285         if not full_sync:
 286             res = self.samdb.search(base=dn, scope=ldb.SCOPE_BASE,
 287                                     attrs=["repsFrom"])
 288             if "repsFrom" in res[0]:
 289                 for reps_from_packed in res[0]["repsFrom"]:
 290                     reps_from_obj = ndr_unpack(drsblobs.repsFromToBlob, reps_from_packed)
 291                     if reps_from_obj.ctr.source_dsa_invocation_id == source_dsa_invocation_id:
 292                         hwm = reps_from_obj.ctr.highwatermark
 293
 294             udv = drsuapi.DsReplicaCursorCtrEx()
 295             udv.version = 1
 296             udv.reserved1 = 0
 297             udv.reserved2 = 0
 298
 299             cursors_v1 = []
 300             cursors_v2 = dsdb._dsdb_load_udv_v2(self.samdb,
 301                                                 self.samdb.get_default_basedn())
 302             for cursor_v2 in cursors_v2:
 303                 cursor_v1 = drsuapi.DsReplicaCursor()
 304                 cursor_v1.source_dsa_invocation_id = cursor_v2.source_dsa_invocation_id
 305                 cursor_v1.highest_usn = cursor_v2.highest_usn
 306                 cursors_v1.append(cursor_v1)
 307
 308             udv.cursors = cursors_v1
 309             udv.count = len(cursors_v1)
 310
 311         req.highwatermark = hwm
 312         req.uptodateness_vector = udv
 313
 314         if replica_flags is not None:
 315             req.replica_flags = replica_flags
 316         elif exop == drsuapi.DRSUAPI_EXOP_REPL_SECRET:
 317             req.replica_flags = 0
 318         else:
 319             req.replica_flags = (drsuapi.DRSUAPI_DRS_INIT_SYNC |
 320                                  drsuapi.DRSUAPI_DRS_PER_SYNC |
 321                                  drsuapi.DRSUAPI_DRS_GET_ANC |
 322                                  drsuapi.DRSUAPI_DRS_NEVER_SYNCED |
 323                                  drsuapi.DRSUAPI_DRS_GET_ALL_GROUP_MEMBERSHIP)
 324             if rodc:
 325                 req.replica_flags |= (
 326                      drsuapi.DRSUAPI_DRS_SPECIAL_SECRET_PROCESSING)
 327             else:
 328                 req.replica_flags |= drsuapi.DRSUAPI_DRS_WRIT_REP
 329
 330         if sync_forced:
 331             req.replica_flags |= drsuapi.DRSUAPI_DRS_SYNC_FORCED
 332
 333         req.max_object_count = 402
 334         req.max_ndr_size = 402116
 335         req.extended_op = exop
 336         req.fsmo_info = 0
 337         req.partial_attribute_set = None
 338         req.partial_attribute_set_ex = None
 339         req.mapping_ctr.num_mappings = 0
 340         req.mapping_ctr.mappings = None
 341
 342         if not schema and rodc:
 343             req.partial_attribute_set = drs_get_rodc_partial_attribute_set(self.samdb)
 344
 345         if not self.supports_ext & DRSUAPI_SUPPORTED_EXTENSION_GETCHGREQ_V8:
 346             req_level = 5
 347             req5 = drsuapi.DsGetNCChangesRequest5()
 348             for a in dir(req5):
 349                 if a[0] != '_':
 350                     setattr(req5, a, getattr(req, a))
 351             req = req5
 352
 353         num_objects = 0
 354         num_links = 0
 355         first_chunk = True
 356
 357         while True:
 358             (level, ctr) = self.drs.DsGetNCChanges(self.drs_handle, req_level, req)
 359             if ctr.first_object is None and ctr.object_count != 0:
 360                 raise RuntimeError("DsGetNCChanges: NULL first_object with object_count=%u" % (ctr.object_count))
 361
 362             try:
 363                 self.process_chunk(level, ctr, schema, req_level, req, first_chunk)
 364             except WERRORError as e:
 365                 # Check if retrying with the GET_TGT flag set might resolve this error
 366                 if self._should_retry_with_get_tgt(e.args[0], req):
 367
 368                     print("Missing target object - retrying with DRS_GET_TGT")
 369                     req.more_flags |= drsuapi.DRSUAPI_DRS_GET_TGT
 370
 371                     # try sending the request again (this has the side-effect
 372                     # of causing the DC to restart the replication from scratch)
 373                     first_chunk = True
 374                     continue
 375
 376                 if self._should_calculate_missing_anc_locally(e.args[0],
 377                                                               req):
 378                     print("Missing parent object - calculating missing objects locally")
 379
 380                     self._calculate_missing_anc_locally(ctr)
 381                 raise e
 382
 383             first_chunk = False
 384             num_objects += ctr.object_count
 385
 386             # Cope with servers that do not return level 6, so do not return any links
 387             try:
 388                 num_links += ctr.linked_attributes_count
 389             except AttributeError:
 390                 pass
 391
 392             if ctr.more_data == 0:
 393                 break
 394
 395             # update the request's HWM so we get the next chunk
 396             drs_copy_highwater_mark(req.highwatermark, ctr.new_highwatermark)
 397
 398         return (num_objects, num_links)
 399
 400
 401 # Handles the special case of creating a new clone of a DB, while also renaming
 402 # the entire DB's objects on the way through
 403 class drs_ReplicateRenamer(drs_Replicate):
 404     """Uses DRS replication to rename the entire DB"""
 405
 406     def __init__(self, binding_string, lp, creds, samdb, invocation_id,
 407                  old_base_dn, new_base_dn):
 408         super().__init__(binding_string, lp, creds, samdb, invocation_id)
 409         self.old_base_dn = old_base_dn
 410         self.new_base_dn = new_base_dn
 411
 412         # because we're renaming the DNs, we know we're going to have trouble
 413         # resolving link targets. Normally we'd get to the end of replication
 414         # only to find we need to retry the whole replication with the GET_TGT
 415         # flag set. Always setting the GET_TGT flag avoids this extra work.
 416         self.more_flags = drsuapi.DRSUAPI_DRS_GET_TGT
 417
 418     def rename_dn(self, dn_str):
 419         """Uses string substitution to replace the base DN"""
 420         return re.sub('%s$' % self.old_base_dn, self.new_base_dn, dn_str)
 421
 422     def update_name_attr(self, base_obj):
 423         """Updates the 'name' attribute for the base DN object"""
 424         for attr in base_obj.attribute_ctr.attributes:
 425             if attr.attid == DRSUAPI_ATTID_name:
 426                 base_dn = ldb.Dn(self.samdb, base_obj.identifier.dn)
 427                 new_name = base_dn.get_rdn_value()
 428                 attr.value_ctr.values[0].blob = new_name.encode('utf-16-le')
 429
 430     def rename_top_level_object(self, first_obj):
 431         """Renames the first/top-level object in a partition"""
 432         old_dn = first_obj.identifier.dn
 433         first_obj.identifier.dn = self.rename_dn(first_obj.identifier.dn)
 434         print("Renaming partition %s --> %s" % (old_dn,
 435                                                 first_obj.identifier.dn))
 436
 437         # we also need to fix up the 'name' attribute for the base DN,
 438         # otherwise the RDNs won't match
 439         if first_obj.identifier.dn == self.new_base_dn:
 440             self.update_name_attr(first_obj)
 441
 442     def process_chunk(self, level, ctr, schema, req_level, req, first_chunk):
 443         """Processes a single chunk of received replication data"""
 444
 445         # we need to rename the NC in every chunk - this gets used in searches
 446         # when applying the chunk
 447         if ctr.naming_context:
 448             ctr.naming_context.dn = self.rename_dn(ctr.naming_context.dn)
 449
 450         # rename the first object in each partition. This will cause every
 451         # subsequent object in the partition to be renamed as a side-effect
 452         if first_chunk and ctr.object_count != 0:
 453             self.rename_top_level_object(ctr.first_object.object)
 454
 455         # then do the normal repl processing to apply this chunk to our DB
 456         super().process_chunk(level, ctr, schema, req_level, req, first_chunk)