Current File : //usr/lib/python3/dist-packages/samba/remove_dc.py
# Unix SMB/CIFS implementation.
# Copyright Matthieu Patou <mat@matws.net> 2011
# Copyright Andrew Bartlett <abartlet@samba.org> 2008-2015
#
# 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/>.
#
import uuid
import ldb
from ldb import LdbError
from samba import werror
from samba.ndr import ndr_unpack
from samba.dcerpc import misc, dnsp
from samba.dcerpc.dnsp import DNS_TYPE_NS, DNS_TYPE_A, DNS_TYPE_AAAA, \
DNS_TYPE_CNAME, DNS_TYPE_SRV, DNS_TYPE_PTR
class DemoteException(Exception):
"""Base element for demote errors"""
def __init__(self, value):
self.value = value
def __str__(self):
return "DemoteException: " + self.value
def remove_sysvol_references(samdb, logger, dc_name):
# DNs under the Configuration DN:
realm = samdb.domain_dns_name()
for s in ("CN=Enterprise,CN=Microsoft System Volumes,CN=System",
"CN=%s,CN=Microsoft System Volumes,CN=System" % realm):
dn = ldb.Dn(samdb, s)
# This is verbose, but it is the safe, escape-proof way
# to add a base and add an arbitrary RDN.
try:
dn.add_base(samdb.get_config_basedn())
except ldb.LdbError:
raise DemoteException("Failed constructing DN %s by adding base %s"
% (dn, samdb.get_config_basedn()))
try:
dn.add_child("CN=X")
except ldb.LdbError:
raise DemoteException("Failed constructing DN %s by adding child CN=X"
% (dn))
dn.set_component(0, "CN", dc_name)
try:
logger.info("Removing Sysvol reference: %s" % dn)
samdb.delete(dn)
except ldb.LdbError as e:
(enum, estr) = e.args
if enum == ldb.ERR_NO_SUCH_OBJECT:
pass
else:
raise
# DNs under the Domain DN:
for s in ("CN=Domain System Volumes (SYSVOL share),CN=File Replication Service,CN=System",
"CN=Topology,CN=Domain System Volume,CN=DFSR-GlobalSettings,CN=System"):
# This is verbose, but it is the safe, escape-proof way
# to add a base and add an arbitrary RDN.
dn = ldb.Dn(samdb, s)
try:
dn.add_base(samdb.get_default_basedn())
except ldb.LdbError:
raise DemoteException("Failed constructing DN %s by adding base %s"
% (dn, samdb.get_default_basedn()))
try:
dn.add_child("CN=X")
except ldb.LdbError:
raise DemoteException("Failed constructing DN %s by adding child "
"CN=X (soon to be CN=%s)" % (dn, dc_name))
dn.set_component(0, "CN", dc_name)
try:
logger.info("Removing Sysvol reference: %s" % dn)
samdb.delete(dn)
except ldb.LdbError as e1:
(enum, estr) = e1.args
if enum == ldb.ERR_NO_SUCH_OBJECT:
pass
else:
raise
def remove_dns_references(samdb, logger, dnsHostName, ignore_no_name=False):
# Check we are using in-database DNS
zones = samdb.search(base="", scope=ldb.SCOPE_SUBTREE,
expression="(&(objectClass=dnsZone)(!(dc=RootDNSServers)))",
attrs=[],
controls=["search_options:0:2"])
if len(zones) == 0:
return
dnsHostNameUpper = dnsHostName.upper()
try:
(dn, primary_recs) = samdb.dns_lookup(dnsHostName)
except RuntimeError as e4:
(enum, estr) = e4.args
if (enum == werror.WERR_DNS_ERROR_NAME_DOES_NOT_EXIST or
enum == werror.WERR_DNS_ERROR_RCODE_NAME_ERROR):
if ignore_no_name:
remove_hanging_dns_references(samdb, logger,
dnsHostNameUpper,
zones)
return
raise DemoteException("lookup of %s failed: %s" % (dnsHostName, estr))
samdb.dns_replace(dnsHostName, [])
res = samdb.search("",
scope=ldb.SCOPE_BASE, attrs=["namingContexts"])
assert len(res) == 1
ncs = res[0]["namingContexts"]
# Work out the set of names we will likely have an A record on by
# default. This is by default all the partitions of type
# domainDNS. By finding the canocial name of all the partitions,
# we find the likely candidates. We only remove the record if it
# matches the IP that was used by the dnsHostName. This avoids us
# needing to look a the dns_update_list file from in the demote
# script.
def dns_name_from_dn(dn):
# The canonical string of DC=example,DC=com is
# example.com/
#
# The canonical string of CN=Configuration,DC=example,DC=com
# is example.com/Configuration
return ldb.Dn(samdb, dn).canonical_str().split('/', 1)[0]
# By using a set here, duplicates via (eg) example.com/Configuration
# do not matter, they become just example.com
a_names_to_remove_from \
= set(dns_name_from_dn(str(dn)) for dn in ncs)
def a_rec_to_remove(dnsRecord):
if dnsRecord.wType == DNS_TYPE_A or dnsRecord.wType == DNS_TYPE_AAAA:
for rec in primary_recs:
if rec.wType == dnsRecord.wType and rec.data == dnsRecord.data:
return True
return False
for a_name in a_names_to_remove_from:
try:
logger.debug("checking for DNS records to remove on %s" % a_name)
(a_rec_dn, a_recs) = samdb.dns_lookup(a_name)
except RuntimeError as e2:
(enum, estr) = e2.args
if enum == werror.WERR_DNS_ERROR_NAME_DOES_NOT_EXIST:
return
raise DemoteException("lookup of %s failed: %s" % (a_name, estr))
orig_num_recs = len(a_recs)
a_recs = [r for r in a_recs if not a_rec_to_remove(r)]
if len(a_recs) != orig_num_recs:
logger.info("updating %s keeping %d values, removing %s values" %
(a_name, len(a_recs), orig_num_recs - len(a_recs)))
samdb.dns_replace(a_name, a_recs)
remove_hanging_dns_references(samdb, logger, dnsHostNameUpper, zones)
def remove_hanging_dns_references(samdb, logger, dnsHostNameUpper, zones):
# Find all the CNAME, NS, PTR and SRV records that point at the
# name we are removing
def to_remove(value):
dnsRecord = ndr_unpack(dnsp.DnssrvRpcRecord, value)
if dnsRecord.wType == DNS_TYPE_NS \
or dnsRecord.wType == DNS_TYPE_CNAME \
or dnsRecord.wType == DNS_TYPE_PTR:
if dnsRecord.data.upper() == dnsHostNameUpper:
return True
elif dnsRecord.wType == DNS_TYPE_SRV:
if dnsRecord.data.nameTarget.upper() == dnsHostNameUpper:
return True
return False
for zone in zones:
logger.debug("checking %s" % zone.dn)
records = samdb.search(base=zone.dn, scope=ldb.SCOPE_SUBTREE,
expression="(&(objectClass=dnsNode)"
"(!(dNSTombstoned=TRUE)))",
attrs=["dnsRecord"])
for record in records:
try:
orig_values = record["dnsRecord"]
except KeyError:
continue
# Remove references to dnsHostName in A, AAAA, NS, CNAME and SRV
values = [ndr_unpack(dnsp.DnssrvRpcRecord, v)
for v in orig_values if not to_remove(v)]
if len(values) != len(orig_values):
logger.info("updating %s keeping %d values, removing %s values"
% (record.dn, len(values),
len(orig_values) - len(values)))
# This requires the values to be unpacked, so this
# has been done in the list comprehension above
samdb.dns_replace_by_dn(record.dn, values)
def offline_remove_server(samdb, logger,
server_dn,
remove_computer_obj=False,
remove_server_obj=False,
remove_sysvol_obj=False,
remove_dns_names=False,
remove_dns_account=False):
res = samdb.search("",
scope=ldb.SCOPE_BASE, attrs=["dsServiceName"])
assert len(res) == 1
my_serviceName = res[0]["dsServiceName"][0]
# Confirm this is really a server object
msgs = samdb.search(base=server_dn,
attrs=["serverReference", "cn",
"dnsHostName"],
scope=ldb.SCOPE_BASE,
expression="(objectClass=server)")
msg = msgs[0]
dc_name = str(msg["cn"][0])
try:
computer_dn = ldb.Dn(samdb, msg["serverReference"][0].decode('utf8'))
except KeyError:
computer_dn = None
try:
dnsHostName = str(msg["dnsHostName"][0])
except KeyError:
dnsHostName = None
if remove_server_obj:
# Remove the server DN (do a tree-delete as it could still have a
# 'DNS Settings' child object if it's a Windows DC)
samdb.delete(server_dn, ["tree_delete:0"])
if computer_dn is not None:
computer_msgs = samdb.search(base=computer_dn,
expression="objectclass=computer",
attrs=["msDS-KrbTgtLink",
"rIDSetReferences",
"cn"],
scope=ldb.SCOPE_BASE)
if "rIDSetReferences" in computer_msgs[0]:
rid_set_dn = str(computer_msgs[0]["rIDSetReferences"][0])
logger.info("Removing RID Set: %s" % rid_set_dn)
samdb.delete(rid_set_dn)
if "msDS-KrbTgtLink" in computer_msgs[0]:
krbtgt_link_dn = str(computer_msgs[0]["msDS-KrbTgtLink"][0])
logger.info("Removing RODC KDC account: %s" % krbtgt_link_dn)
samdb.delete(krbtgt_link_dn)
if remove_computer_obj:
# Delete the computer tree
logger.info("Removing computer account: %s (and any child objects)" % computer_dn)
samdb.delete(computer_dn, ["tree_delete:0"])
if "dnsHostName" in msg:
dnsHostName = str(msg["dnsHostName"][0])
if remove_dns_account:
res = samdb.search(expression="(&(objectclass=user)(cn=dns-%s)(servicePrincipalName=DNS/%s))" %
(ldb.binary_encode(dc_name), dnsHostName),
attrs=[], scope=ldb.SCOPE_SUBTREE,
base=samdb.get_default_basedn())
if len(res) == 1:
logger.info("Removing Samba-specific DNS service account: %s" % res[0].dn)
samdb.delete(res[0].dn)
if dnsHostName is not None and remove_dns_names:
remove_dns_references(samdb, logger, dnsHostName)
if remove_sysvol_obj:
remove_sysvol_references(samdb, logger, dc_name)
def offline_remove_ntds_dc(samdb,
logger,
ntds_dn,
remove_computer_obj=False,
remove_server_obj=False,
remove_connection_obj=False,
seize_stale_fsmo=False,
remove_sysvol_obj=False,
remove_dns_names=False,
remove_dns_account=False):
res = samdb.search("",
scope=ldb.SCOPE_BASE, attrs=["dsServiceName"])
assert len(res) == 1
my_serviceName = ldb.Dn(samdb, res[0]["dsServiceName"][0].decode('utf8'))
server_dn = ntds_dn.parent()
if my_serviceName == ntds_dn:
raise DemoteException("Refusing to demote our own DSA: %s " % my_serviceName)
try:
msgs = samdb.search(base=ntds_dn, expression="objectClass=ntdsDSA",
attrs=["objectGUID"], scope=ldb.SCOPE_BASE)
except LdbError as e5:
(enum, estr) = e5.args
if enum == ldb.ERR_NO_SUCH_OBJECT:
raise DemoteException("Given DN %s doesn't exist" % ntds_dn)
else:
raise
if (len(msgs) == 0):
raise DemoteException("%s is not an ntdsda in %s"
% (ntds_dn, samdb.domain_dns_name()))
msg = msgs[0]
if (msg.dn.get_rdn_name() != "CN" or
msg.dn.get_rdn_value() != "NTDS Settings"):
raise DemoteException("Given DN (%s) wasn't the NTDS Settings DN" %
ntds_dn)
ntds_guid = ndr_unpack(misc.GUID, msg["objectGUID"][0])
if remove_connection_obj:
# Find any nTDSConnection objects with that DC as the fromServer.
# We use the GUID to avoid issues with any () chars in a server
# name.
stale_connections = samdb.search(base=samdb.get_config_basedn(),
expression="(&(objectclass=nTDSConnection)"
"(fromServer=<GUID=%s>))" % ntds_guid)
for conn in stale_connections:
logger.info("Removing nTDSConnection: %s" % conn.dn)
samdb.delete(conn.dn)
if seize_stale_fsmo:
stale_fsmo_roles = samdb.search(base="", scope=ldb.SCOPE_SUBTREE,
expression="(fsmoRoleOwner=<GUID=%s>))"
% ntds_guid,
controls=["search_options:0:2"])
# Find any FSMO roles they have, give them to this server
for role in stale_fsmo_roles:
val = str(my_serviceName)
m = ldb.Message()
m.dn = role.dn
m['value'] = ldb.MessageElement(val, ldb.FLAG_MOD_REPLACE,
'fsmoRoleOwner')
logger.warning("Seizing FSMO role on: %s (now owned by %s)"
% (role.dn, my_serviceName))
samdb.modify(m)
# Remove the NTDS setting tree
try:
logger.info("Removing nTDSDSA: %s (and any children)" % ntds_dn)
samdb.delete(ntds_dn, ["tree_delete:0"])
except LdbError as e6:
(enum, estr) = e6.args
raise DemoteException("Failed to remove the DCs NTDS DSA object: %s"
% estr)
offline_remove_server(samdb, logger, server_dn,
remove_computer_obj=remove_computer_obj,
remove_server_obj=remove_server_obj,
remove_sysvol_obj=remove_sysvol_obj,
remove_dns_names=remove_dns_names,
remove_dns_account=remove_dns_account)
def remove_dc(samdb, logger, dc_name):
# TODO: Check if this is the last server (covered mostly by
# refusing to remove our own name)
samdb.transaction_start()
server_dn = None
# Allow the name to be a the nTDS-DSA GUID
try:
ntds_guid = uuid.UUID(hex=dc_name)
ntds_dn = "<GUID=%s>" % ntds_guid
except ValueError:
try:
server_msgs = samdb.search(base=samdb.get_config_basedn(),
attrs=[],
expression="(&(objectClass=server)"
"(cn=%s))"
% ldb.binary_encode(dc_name))
except LdbError as e3:
(enum, estr) = e3.args
raise DemoteException("Failure checking if %s is an server "
"object in %s: %s"
% (dc_name, samdb.domain_dns_name(), estr))
if (len(server_msgs) == 0):
samdb.transaction_cancel()
raise DemoteException("%s is not an AD DC in %s"
% (dc_name, samdb.domain_dns_name()))
server_dn = server_msgs[0].dn
ntds_dn = ldb.Dn(samdb, "CN=NTDS Settings")
ntds_dn.add_base(server_dn)
# Confirm this is really an ntdsDSA object
try:
ntds_msgs = samdb.search(base=ntds_dn, attrs=[], scope=ldb.SCOPE_BASE,
expression="(objectClass=ntdsdsa)")
except LdbError as e7:
(enum, estr) = e7.args
if enum == ldb.ERR_NO_SUCH_OBJECT:
ntds_msgs = []
else:
samdb.transaction_cancel()
raise DemoteException(
"Failure checking if %s is an NTDS DSA in %s: %s" %
(ntds_dn, samdb.domain_dns_name(), estr))
# If the NTDS Settings child DN wasn't found or wasn't an ntdsDSA
# object, just remove the server object located above
if (len(ntds_msgs) == 0):
if server_dn is None:
samdb.transaction_cancel()
raise DemoteException("%s is not an AD DC in %s"
% (dc_name, samdb.domain_dns_name()))
offline_remove_server(samdb, logger,
server_dn,
remove_computer_obj=True,
remove_server_obj=True,
remove_sysvol_obj=True,
remove_dns_names=True,
remove_dns_account=True)
else:
offline_remove_ntds_dc(samdb, logger,
ntds_msgs[0].dn,
remove_computer_obj=True,
remove_server_obj=True,
remove_connection_obj=True,
seize_stale_fsmo=True,
remove_sysvol_obj=True,
remove_dns_names=True,
remove_dns_account=True)
samdb.transaction_commit()
def offline_remove_dc_RemoveDsServer(samdb, ntds_dn):
samdb.start_transaction()
offline_remove_ntds_dc(samdb, ntds_dn, None)
samdb.commit_transaction()
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