1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
|
#!/usr/bin/env python3
# vim: expandtab
#
# update our DNS names using TSIG-GSS
#
# Copyright (C) Andrew Tridgell 2010
#
# 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 os
import fcntl
import sys
import tempfile
import subprocess
# ensure we get messages out immediately, so they get in the samba logs,
# and don't get swallowed by a timeout
os.environ['PYTHONUNBUFFERED'] = '1'
# forcing GMT avoids a problem in some timezones with kerberos. Both MIT
# heimdal can get mutual authentication errors due to the 24 second difference
# between UTC and GMT when using some zone files (eg. the PDT zone from
# the US)
os.environ["TZ"] = "GMT"
# Find right directory when running from source tree
sys.path.insert(0, "bin/python")
import samba
import optparse
from samba import getopt as options
from ldb import SCOPE_BASE
from samba import dsdb
from samba.auth import system_session
from samba.samdb import SamDB
from samba.dcerpc import netlogon, winbind
from samba.netcmd.dns import cmd_dns
from samba import gensec
from samba.kcc import kcc_utils
from samba.compat import get_string
from samba.compat import text_type
import ldb
import dns.resolver
import dns.exception
default_ttl = 900
am_rodc = False
error_count = 0
parser = optparse.OptionParser("samba_dnsupdate [options]")
sambaopts = options.SambaOptions(parser)
parser.add_option_group(sambaopts)
parser.add_option_group(options.VersionOptions(parser))
parser.add_option("--verbose", action="store_true")
parser.add_option("--use-samba-tool", action="store_true", help="Use samba-tool to make updates over RPC, rather than over DNS")
parser.add_option("--use-nsupdate", action="store_true", help="Use nsupdate command to make updates over DNS (default, if kinit successful)")
parser.add_option("--all-names", action="store_true")
parser.add_option("--all-interfaces", action="store_true")
parser.add_option("--current-ip", action="append", help="IP address to update DNS to match (helpful if behind NAT, valid multiple times, defaults to values from interfaces=)")
parser.add_option("--rpc-server-ip", type="string", help="IP address of server to use with samba-tool (defaults to first --current-ip)")
parser.add_option("--use-file", type="string", help="Use a file, rather than real DNS calls")
parser.add_option("--update-list", type="string", help="Add DNS names from the given file")
parser.add_option("--update-cache", type="string", help="Cache database of already registered records")
parser.add_option("--fail-immediately", action='store_true', help="Exit on first failure")
parser.add_option("--no-credentials", dest='nocreds', action='store_true', help="don't try and get credentials")
parser.add_option("--no-substitutions", dest='nosubs', action='store_true', help="don't try and expands variables in file specified by --update-list")
creds = None
ccachename = None
opts, args = parser.parse_args()
if len(args) != 0:
parser.print_usage()
sys.exit(1)
lp = sambaopts.get_loadparm()
domain = lp.get("realm")
host = lp.get("netbios name")
all_interfaces = opts.all_interfaces
IPs = opts.current_ip or samba.interface_ips(lp, bool(all_interfaces)) or []
nsupdate_cmd = lp.get('nsupdate command')
dns_zone_scavenging = lp.get("dns zone scavenging")
if len(IPs) == 0:
print("No IP interfaces - skipping DNS updates\n")
parser.print_usage()
sys.exit(0)
rpc_server_ip = opts.rpc_server_ip or IPs[0]
IP6s = [ip for ip in IPs if ':' in ip]
IP4s = [ip for ip in IPs if ':' not in ip]
smb_conf = sambaopts.get_loadparm_path()
if opts.verbose:
print("IPs: %s" % IPs)
def get_possible_rw_dns_server(creds, domain):
"""Get a list of possible read-write DNS servers, starting with
the SOA. The SOA is the correct answer, but old Samba domains
(4.6 and prior) do not maintain this value, so add NS servers
as well"""
ans_soa = check_one_dns_name(domain, 'SOA')
# Actually there is only one
hosts_soa = [str(a.mname).rstrip('.') for a in ans_soa]
# This is not strictly legit, but old Samba domains may have an
# unmaintained SOA record, so go for any NS that we can get a
# ticket to.
ans_ns = check_one_dns_name(domain, 'NS')
# Actually there is only one
hosts_ns = [str(a.target).rstrip('.') for a in ans_ns]
return hosts_soa + hosts_ns
def get_krb5_rw_dns_server(creds, domain):
"""Get a list of read-write DNS servers that we can obtain a ticket
for, starting with the SOA. The SOA is the correct answer, but
old Samba domains (4.6 and prior) do not maintain this value,
so continue with the NS servers as well until we get one that
the KDC will issue a ticket to.
"""
rw_dns_servers = get_possible_rw_dns_server(creds, domain)
# Actually there is only one
for i, target_hostname in enumerate(rw_dns_servers):
settings = {}
settings["lp_ctx"] = lp
settings["target_hostname"] = target_hostname
gensec_client = gensec.Security.start_client(settings)
gensec_client.set_credentials(creds)
gensec_client.set_target_service("DNS")
gensec_client.set_target_hostname(target_hostname)
gensec_client.want_feature(gensec.FEATURE_SEAL)
gensec_client.start_mech_by_sasl_name("GSSAPI")
server_to_client = b""
try:
(client_finished, client_to_server) = gensec_client.update(server_to_client)
if opts.verbose:
print("Successfully obtained Kerberos ticket to DNS/%s as %s" \
% (target_hostname, creds.get_username()))
return target_hostname
except RuntimeError:
# Only raise an exception if they all failed
if i == len(rw_dns_servers) - 1:
raise
def get_credentials(lp):
"""# get credentials if we haven't got them already."""
from samba import credentials
global ccachename
creds = credentials.Credentials()
creds.guess(lp)
creds.set_machine_account(lp)
creds.set_krb_forwardable(credentials.NO_KRB_FORWARDABLE)
(tmp_fd, ccachename) = tempfile.mkstemp()
try:
if opts.use_file is not None:
return
creds.get_named_ccache(lp, ccachename)
# Now confirm we can get a ticket to the DNS server
get_krb5_rw_dns_server(creds, sub_vars['DNSDOMAIN'] + '.')
return creds
except RuntimeError as e:
os.unlink(ccachename)
raise e
class dnsobj(object):
"""an object to hold a parsed DNS line"""
def __init__(self, string_form):
list = string_form.split()
if len(list) < 3:
raise Exception("Invalid DNS entry %r" % string_form)
self.dest = None
self.port = None
self.ip = None
self.existing_port = None
self.existing_weight = None
self.existing_cname_target = None
self.rpc = False
self.zone = None
if list[0] == "RPC":
self.rpc = True
self.zone = list[1]
list = list[2:]
self.type = list[0]
self.name = list[1]
self.nameservers = []
if self.type == 'SRV':
if len(list) < 4:
raise Exception("Invalid DNS entry %r" % string_form)
self.dest = list[2]
self.port = list[3]
elif self.type in ['A', 'AAAA']:
self.ip = list[2] # usually $IP, which gets replaced
elif self.type == 'CNAME':
self.dest = list[2]
elif self.type == 'NS':
self.dest = list[2]
else:
raise Exception("Received unexpected DNS reply of type %s: %s" % (self.type, string_form))
def __str__(self):
if self.type == "A":
return "%s %s %s" % (self.type, self.name, self.ip)
if self.type == "AAAA":
return "%s %s %s" % (self.type, self.name, self.ip)
if self.type == "SRV":
return "%s %s %s %s" % (self.type, self.name, self.dest, self.port)
if self.type == "CNAME":
return "%s %s %s" % (self.type, self.name, self.dest)
if self.type == "NS":
return "%s %s %s" % (self.type, self.name, self.dest)
def parse_dns_line(line, sub_vars):
"""parse a DNS line from."""
if line.startswith("SRV _ldap._tcp.pdc._msdcs.") and not samdb.am_pdc():
# We keep this as compat to the dns_update_list of 4.0/4.1
if opts.verbose:
print("Skipping PDC entry (%s) as we are not a PDC" % line)
return None
subline = samba.substitute_var(line, sub_vars)
if subline == '' or subline[0] == "#":
return None
return dnsobj(subline)
def hostname_match(h1, h2):
"""see if two hostnames match."""
h1 = str(h1)
h2 = str(h2)
return h1.lower().rstrip('.') == h2.lower().rstrip('.')
def get_resolver(d=None):
resolv_conf = os.getenv('RESOLV_CONF', default='/etc/resolv.conf')
resolver = dns.resolver.Resolver(filename=resolv_conf, configure=True)
if d is not None and d.nameservers != []:
resolver.nameservers = d.nameservers
return resolver
def check_one_dns_name(name, name_type, d=None):
resolver = get_resolver(d)
if d and not d.nameservers:
d.nameservers = resolver.nameservers
# dns.resolver.Answer
return resolver.query(name, name_type)
def check_dns_name(d):
"""check that a DNS entry exists."""
normalised_name = d.name.rstrip('.') + '.'
if opts.verbose:
print("Looking for DNS entry %s as %s" % (d, normalised_name))
if opts.use_file is not None:
try:
dns_file = open(opts.use_file, "r")
except IOError:
return False
for line in dns_file:
line = line.strip()
if line == '' or line[0] == "#":
continue
if line.lower() == str(d).lower():
return True
return False
try:
ans = check_one_dns_name(normalised_name, d.type, d)
except dns.exception.Timeout:
raise Exception("Timeout while waiting to contact a working DNS server while looking for %s as %s" % (d, normalised_name))
except dns.resolver.NoNameservers:
raise Exception("Unable to contact a working DNS server while looking for %s as %s" % (d, normalised_name))
except dns.resolver.NXDOMAIN:
if opts.verbose:
print("The DNS entry %s, queried as %s does not exist" % (d, normalised_name))
return False
except dns.resolver.NoAnswer:
if opts.verbose:
print("The DNS entry %s, queried as %s does not hold this record type" % (d, normalised_name))
return False
except dns.exception.DNSException:
raise Exception("Failure while trying to resolve %s as %s" % (d, normalised_name))
if d.type in ['A', 'AAAA']:
# we need to be sure that our IP is there
for rdata in ans:
if str(rdata) == str(d.ip):
return True
elif d.type == 'CNAME':
for i in range(len(ans)):
if hostname_match(ans[i].target, d.dest):
return True
else:
d.existing_cname_target = str(ans[i].target)
elif d.type == 'NS':
for i in range(len(ans)):
if hostname_match(ans[i].target, d.dest):
return True
elif d.type == 'SRV':
for rdata in ans:
if opts.verbose:
print("Checking %s against %s" % (rdata, d))
if hostname_match(rdata.target, d.dest):
if str(rdata.port) == str(d.port):
return True
else:
d.existing_port = str(rdata.port)
d.existing_weight = str(rdata.weight)
if opts.verbose:
print("Lookup of %s succeeded, but we failed to find a matching DNS entry for %s" % (normalised_name, d))
return False
def get_subst_vars(samdb):
"""get the list of substitution vars."""
global lp, am_rodc
vars = {}
vars['DNSDOMAIN'] = samdb.domain_dns_name()
vars['DNSFOREST'] = samdb.forest_dns_name()
vars['HOSTNAME'] = samdb.host_dns_name()
vars['NTDSGUID'] = samdb.get_ntds_GUID()
vars['SITE'] = samdb.server_site_name()
res = samdb.search(base=samdb.get_default_basedn(), scope=SCOPE_BASE, attrs=["objectGUID"])
guid = samdb.schema_format_value("objectGUID", res[0]['objectGUID'][0])
vars['DOMAINGUID'] = get_string(guid)
vars['IF_DC'] = ""
vars['IF_RWDC'] = "# "
vars['IF_RODC'] = "# "
vars['IF_PDC'] = "# "
vars['IF_GC'] = "# "
vars['IF_RWGC'] = "# "
vars['IF_ROGC'] = "# "
vars['IF_DNS_DOMAIN'] = "# "
vars['IF_RWDNS_DOMAIN'] = "# "
vars['IF_RODNS_DOMAIN'] = "# "
vars['IF_DNS_FOREST'] = "# "
vars['IF_RWDNS_FOREST'] = "# "
vars['IF_R0DNS_FOREST'] = "# "
am_rodc = samdb.am_rodc()
if am_rodc:
vars['IF_RODC'] = ""
else:
vars['IF_RWDC'] = ""
if samdb.am_pdc():
vars['IF_PDC'] = ""
# check if we "are DNS server"
res = samdb.search(base=samdb.get_config_basedn(),
expression='(objectguid=%s)' % vars['NTDSGUID'],
attrs=["options", "msDS-hasMasterNCs"])
if len(res) == 1:
if "options" in res[0]:
options = int(res[0]["options"][0])
if (options & dsdb.DS_NTDSDSA_OPT_IS_GC) != 0:
vars['IF_GC'] = ""
if am_rodc:
vars['IF_ROGC'] = ""
else:
vars['IF_RWGC'] = ""
basedn = str(samdb.get_default_basedn())
forestdn = str(samdb.get_root_basedn())
if "msDS-hasMasterNCs" in res[0]:
for e in res[0]["msDS-hasMasterNCs"]:
if str(e) == "DC=DomainDnsZones,%s" % basedn:
vars['IF_DNS_DOMAIN'] = ""
if am_rodc:
vars['IF_RODNS_DOMAIN'] = ""
else:
vars['IF_RWDNS_DOMAIN'] = ""
if str(e) == "DC=ForestDnsZones,%s" % forestdn:
vars['IF_DNS_FOREST'] = ""
if am_rodc:
vars['IF_RODNS_FOREST'] = ""
else:
vars['IF_RWDNS_FOREST'] = ""
return vars
def call_nsupdate(d, op="add"):
"""call nsupdate for an entry."""
global ccachename, nsupdate_cmd, krb5conf
assert(op in ["add", "delete"])
if opts.use_file is not None:
if opts.verbose:
print("Use File instead of nsupdate for %s (%s)" % (d, op))
try:
rfile = open(opts.use_file, 'r+')
except IOError:
# Perhaps create it
rfile = open(opts.use_file, 'w+')
# Open it for reading again, in case someone else got to it first
rfile = open(opts.use_file, 'r+')
fcntl.lockf(rfile, fcntl.LOCK_EX)
(file_dir, file_name) = os.path.split(opts.use_file)
(tmp_fd, tmpfile) = tempfile.mkstemp(dir=file_dir, prefix=file_name, suffix="XXXXXX")
wfile = os.fdopen(tmp_fd, 'a')
rfile.seek(0)
for line in rfile:
if op == "delete":
l = parse_dns_line(line, {})
if str(l).lower() == str(d).lower():
continue
wfile.write(line)
if op == "add":
wfile.write(str(d)+"\n")
os.rename(tmpfile, opts.use_file)
fcntl.lockf(rfile, fcntl.LOCK_UN)
return
if opts.verbose:
print("Calling nsupdate for %s (%s)" % (d, op))
normalised_name = d.name.rstrip('.') + '.'
(tmp_fd, tmpfile) = tempfile.mkstemp()
f = os.fdopen(tmp_fd, 'w')
resolver = get_resolver(d)
# Local the zone for this name
zone = dns.resolver.zone_for_name(normalised_name,
resolver=resolver)
# Now find the SOA, or if we can't get a ticket to the SOA,
# any server with an NS record we can get a ticket for.
#
# Thanks to the Kerberos Credentials cache this is not
# expensive inside the loop
server = get_krb5_rw_dns_server(creds, zone)
f.write('server %s\n' % server)
if d.type == "A":
f.write("update %s %s %u A %s\n" % (op, normalised_name, default_ttl, d.ip))
if d.type == "AAAA":
f.write("update %s %s %u AAAA %s\n" % (op, normalised_name, default_ttl, d.ip))
if d.type == "SRV":
if op == "add" and d.existing_port is not None:
f.write("update delete %s SRV 0 %s %s %s\n" % (normalised_name, d.existing_weight,
d.existing_port, d.dest))
f.write("update %s %s %u SRV 0 100 %s %s\n" % (op, normalised_name, default_ttl, d.port, d.dest))
if d.type == "CNAME":
f.write("update %s %s %u CNAME %s\n" % (op, normalised_name, default_ttl, d.dest))
if d.type == "NS":
f.write("update %s %s %u NS %s\n" % (op, normalised_name, default_ttl, d.dest))
if opts.verbose:
f.write("show\n")
f.write("send\n")
f.close()
# Set a bigger MTU size to work around a bug in nsupdate's doio_send()
os.environ["SOCKET_WRAPPER_MTU"] = "2000"
global error_count
if ccachename:
os.environ["KRB5CCNAME"] = ccachename
try:
cmd = nsupdate_cmd[:]
cmd.append(tmpfile)
env = os.environ
if krb5conf:
env["KRB5_CONFIG"] = krb5conf
if ccachename:
env["KRB5CCNAME"] = ccachename
ret = subprocess.call(cmd, shell=False, env=env)
if ret != 0:
if opts.fail_immediately:
if opts.verbose:
print("Failed update with %s" % tmpfile)
sys.exit(1)
error_count = error_count + 1
if opts.verbose:
print("Failed nsupdate: %d" % ret)
except Exception as estr:
if opts.fail_immediately:
sys.exit(1)
error_count = error_count + 1
if opts.verbose:
print("Failed nsupdate: %s : %s" % (str(d), estr))
os.unlink(tmpfile)
# Let socket_wrapper set the default MTU size
os.environ["SOCKET_WRAPPER_MTU"] = "0"
def call_samba_tool(d, op="add", zone=None):
"""call samba-tool dns to update an entry."""
assert(op in ["add", "delete"])
if (sub_vars['DNSFOREST'] != sub_vars['DNSDOMAIN']) and \
sub_vars['DNSFOREST'].endswith('.' + sub_vars['DNSDOMAIN']):
print("Refusing to use samba-tool when forest %s is under domain %s" \
% (sub_vars['DNSFOREST'], sub_vars['DNSDOMAIN']))
if opts.verbose:
print("Calling samba-tool dns for %s (%s)" % (d, op))
normalised_name = d.name.rstrip('.') + '.'
if zone is None:
if normalised_name == (sub_vars['DNSDOMAIN'] + '.'):
short_name = '@'
zone = sub_vars['DNSDOMAIN']
elif normalised_name == (sub_vars['DNSFOREST'] + '.'):
short_name = '@'
zone = sub_vars['DNSFOREST']
elif normalised_name == ('_msdcs.' + sub_vars['DNSFOREST'] + '.'):
short_name = '@'
zone = '_msdcs.' + sub_vars['DNSFOREST']
else:
if not normalised_name.endswith('.' + sub_vars['DNSDOMAIN'] + '.'):
print("Not Calling samba-tool dns for %s (%s), %s not in %s" % (d, op, normalised_name, sub_vars['DNSDOMAIN'] + '.'))
return False
elif normalised_name.endswith('._msdcs.' + sub_vars['DNSFOREST'] + '.'):
zone = '_msdcs.' + sub_vars['DNSFOREST']
else:
zone = sub_vars['DNSDOMAIN']
len_zone = len(zone)+2
short_name = normalised_name[:-len_zone]
else:
len_zone = len(zone)+2
short_name = normalised_name[:-len_zone]
if d.type == "A":
args = [rpc_server_ip, zone, short_name, "A", d.ip]
if d.type == "AAAA":
args = [rpc_server_ip, zone, short_name, "AAAA", d.ip]
if d.type == "SRV":
if op == "add" and d.existing_port is not None:
print("Not handling modify of exising SRV %s using samba-tool" % d)
return False
op = "update"
args = [rpc_server_ip, zone, short_name, "SRV",
"%s %s %s %s" % (d.existing_weight,
d.existing_port, "0", "100"),
"%s %s %s %s" % (d.dest, d.port, "0", "100")]
else:
args = [rpc_server_ip, zone, short_name, "SRV", "%s %s %s %s" % (d.dest, d.port, "0", "100")]
if d.type == "CNAME":
if d.existing_cname_target is None:
args = [rpc_server_ip, zone, short_name, "CNAME", d.dest]
else:
op = "update"
args = [rpc_server_ip, zone, short_name, "CNAME",
d.existing_cname_target.rstrip('.'), d.dest]
if d.type == "NS":
args = [rpc_server_ip, zone, short_name, "NS", d.dest]
if smb_conf and args:
args += ["--configfile=" + smb_conf]
global error_count
try:
cmd = cmd_dns()
if opts.verbose:
print("Calling samba-tool dns %s -k no -P %s" % (op, args))
ret = cmd._run("dns", op, "-k", "no", "-P", *args)
if ret == -1:
if opts.fail_immediately:
sys.exit(1)
error_count = error_count + 1
if opts.verbose:
print("Failed 'samba-tool dns' based update of %s" % (str(d)))
except Exception as estr:
if opts.fail_immediately:
sys.exit(1)
error_count = error_count + 1
if opts.verbose:
print("Failed 'samba-tool dns' based update: %s : %s" % (str(d), estr))
raise
irpc_wb = None
def cached_irpc_wb(lp):
global irpc_wb
if irpc_wb is not None:
return irpc_wb
irpc_wb = winbind.winbind("irpc:winbind_server", lp)
return irpc_wb
def rodc_dns_update(d, t, op):
'''a single DNS update via the RODC netlogon call'''
global sub_vars
assert(op in ["add", "delete"])
if opts.verbose:
print("Calling netlogon RODC update for %s" % d)
typemap = {
netlogon.NlDnsLdapAtSite : netlogon.NlDnsInfoTypeNone,
netlogon.NlDnsGcAtSite : netlogon.NlDnsDomainNameAlias,
netlogon.NlDnsDsaCname : netlogon.NlDnsDomainNameAlias,
netlogon.NlDnsKdcAtSite : netlogon.NlDnsInfoTypeNone,
netlogon.NlDnsDcAtSite : netlogon.NlDnsInfoTypeNone,
netlogon.NlDnsRfc1510KdcAtSite : netlogon.NlDnsInfoTypeNone,
netlogon.NlDnsGenericGcAtSite : netlogon.NlDnsDomainNameAlias
}
w = cached_irpc_wb(lp)
dns_names = netlogon.NL_DNS_NAME_INFO_ARRAY()
dns_names.count = 1
name = netlogon.NL_DNS_NAME_INFO()
name.type = t
name.dns_domain_info_type = typemap[t]
name.priority = 0
name.weight = 0
if d.port is not None:
name.port = int(d.port)
if op == "add":
name.dns_register = True
else:
name.dns_register = False
dns_names.names = [ name ]
site_name = text_type(sub_vars['SITE'])
global error_count
try:
ret_names = w.DsrUpdateReadOnlyServerDnsRecords(site_name, default_ttl, dns_names)
if ret_names.names[0].status != 0:
print("Failed to set DNS entry: %s (status %u)" % (d, ret_names.names[0].status))
error_count = error_count + 1
except RuntimeError as reason:
print("Error setting DNS entry of type %u: %s: %s" % (t, d, reason))
error_count = error_count + 1
if opts.verbose:
print("Called netlogon RODC update for %s" % d)
if error_count != 0 and opts.fail_immediately:
sys.exit(1)
def call_rodc_update(d, op="add"):
'''RODCs need to use the netlogon API for nsupdate'''
global lp, sub_vars
assert(op in ["add", "delete"])
# we expect failure for 3268 if we aren't a GC
if d.port is not None and int(d.port) == 3268:
return
# map the DNS request to a netlogon update type
map = {
netlogon.NlDnsLdapAtSite : '_ldap._tcp.${SITE}._sites.${DNSDOMAIN}',
netlogon.NlDnsGcAtSite : '_ldap._tcp.${SITE}._sites.gc._msdcs.${DNSDOMAIN}',
netlogon.NlDnsDsaCname : '${NTDSGUID}._msdcs.${DNSFOREST}',
netlogon.NlDnsKdcAtSite : '_kerberos._tcp.${SITE}._sites.dc._msdcs.${DNSDOMAIN}',
netlogon.NlDnsDcAtSite : '_ldap._tcp.${SITE}._sites.dc._msdcs.${DNSDOMAIN}',
netlogon.NlDnsRfc1510KdcAtSite : '_kerberos._tcp.${SITE}._sites.${DNSDOMAIN}',
netlogon.NlDnsGenericGcAtSite : '_gc._tcp.${SITE}._sites.${DNSFOREST}'
}
for t in map:
subname = samba.substitute_var(map[t], sub_vars)
if subname.lower() == d.name.lower():
# found a match - do the update
rodc_dns_update(d, t, op)
return
if opts.verbose:
print("Unable to map to netlogon DNS update: %s" % d)
# get the list of DNS entries we should have
dns_update_list = opts.update_list or lp.private_path('dns_update_list')
dns_update_cache = opts.update_cache or lp.private_path('dns_update_cache')
krb5conf = None
# only change the krb5.conf if we are not in selftest
if 'SOCKET_WRAPPER_DIR' not in os.environ:
# use our private krb5.conf to avoid problems with the wrong domain
# bind9 nsupdate wants the default domain set
krb5conf = lp.private_path('krb5.conf')
os.environ['KRB5_CONFIG'] = krb5conf
try:
file = open(dns_update_list, "r")
except OSError as e:
if opts.update_cache:
print("The specified update list does not exist")
else:
print("The server update list was not found, "
"and --update-list was not provided.")
print(e)
print()
parser.print_usage()
sys.exit(1)
if opts.nosubs:
sub_vars = {}
else:
samdb = SamDB(url=lp.samdb_url(), session_info=system_session(), lp=lp)
# get the substitution dictionary
sub_vars = get_subst_vars(samdb)
# build up a list of update commands to pass to nsupdate
update_list = []
dns_list = []
cache_list = []
delete_list = []
dup_set = set()
cache_set = set()
rebuild_cache = False
try:
cfile = open(dns_update_cache, 'r+')
except IOError:
# Perhaps create it
cfile = open(dns_update_cache, 'w+')
# Open it for reading again, in case someone else got to it first
cfile = open(dns_update_cache, 'r+')
fcntl.lockf(cfile, fcntl.LOCK_EX)
for line in cfile:
line = line.strip()
if line == '' or line[0] == "#":
continue
c = parse_dns_line(line, {})
if c is None:
continue
if str(c) not in cache_set:
cache_list.append(c)
cache_set.add(str(c))
site_specific_rec = []
# read each line, and check that the DNS name exists
for line in file:
line = line.strip()
if '${SITE}' in line:
site_specific_rec.append(line)
if line == '' or line[0] == "#":
continue
d = parse_dns_line(line, sub_vars)
if d is None:
continue
if d.type == 'A' and len(IP4s) == 0:
continue
if d.type == 'AAAA' and len(IP6s) == 0:
continue
if str(d) not in dup_set:
dns_list.append(d)
dup_set.add(str(d))
# Perform automatic site coverage by default
auto_coverage = True
if not am_rodc and auto_coverage:
site_names = kcc_utils.uncovered_sites_to_cover(samdb,
samdb.server_site_name())
# Duplicate all site specific records for the uncovered site
for site in site_names:
to_add = [samba.substitute_var(line, {'SITE': site})
for line in site_specific_rec]
for site_line in to_add:
d = parse_dns_line(site_line,
sub_vars=sub_vars)
if d is not None and str(d) not in dup_set:
dns_list.append(d)
dup_set.add(str(d))
# now expand the entries, if any are A record with ip set to $IP
# then replace with multiple entries, one for each interface IP
for d in dns_list:
if d.ip != "$IP":
continue
if d.type == 'A':
d.ip = IP4s[0]
for i in range(len(IP4s)-1):
d2 = dnsobj(str(d))
d2.ip = IP4s[i+1]
dns_list.append(d2)
if d.type == 'AAAA':
d.ip = IP6s[0]
for i in range(len(IP6s)-1):
d2 = dnsobj(str(d))
d2.ip = IP6s[i+1]
dns_list.append(d2)
# now check if the entries already exist on the DNS server
for d in dns_list:
found = False
for c in cache_list:
if str(c).lower() == str(d).lower():
found = True
break
if not found:
rebuild_cache = True
if opts.verbose:
print("need cache add: %s" % d)
if dns_zone_scavenging:
update_list.append(d)
if opts.verbose:
print("scavenging requires update: %s" % d)
elif opts.all_names:
update_list.append(d)
if opts.verbose:
print("force update: %s" % d)
elif not check_dns_name(d):
update_list.append(d)
if opts.verbose:
print("need update: %s" % d)
for c in cache_list:
found = False
for d in dns_list:
if str(c).lower() == str(d).lower():
found = True
break
if found:
continue
rebuild_cache = True
if opts.verbose:
print("need cache remove: %s" % c)
if not opts.all_names and not check_dns_name(c):
continue
delete_list.append(c)
if opts.verbose:
print("need delete: %s" % c)
if len(delete_list) == 0 and len(update_list) == 0 and not rebuild_cache:
if opts.verbose:
print("No DNS updates needed")
sys.exit(0)
else:
if opts.verbose:
print("%d DNS updates and %d DNS deletes needed" % (len(update_list), len(delete_list)))
use_samba_tool = opts.use_samba_tool
use_nsupdate = opts.use_nsupdate
# get our krb5 creds
if delete_list or update_list and not opts.nocreds:
try:
creds = get_credentials(lp)
except RuntimeError as e:
ccachename = None
if sub_vars['IF_RWDNS_DOMAIN'] == "# ":
raise
if use_nsupdate:
raise
print("Failed to get Kerberos credentials, falling back to samba-tool: %s" % e)
use_samba_tool = True
# ask nsupdate to delete entries as needed
for d in delete_list:
if d.rpc or (not use_nsupdate and use_samba_tool):
if opts.verbose:
print("update (samba-tool): %s" % d)
call_samba_tool(d, op="delete", zone=d.zone)
elif am_rodc:
if d.name.lower() == domain.lower():
if opts.verbose:
print("skip delete (rodc): %s" % d)
continue
if not d.type in [ 'A', 'AAAA' ]:
if opts.verbose:
print("delete (rodc): %s" % d)
call_rodc_update(d, op="delete")
else:
if opts.verbose:
print("delete (nsupdate): %s" % d)
call_nsupdate(d, op="delete")
else:
if opts.verbose:
print("delete (nsupdate): %s" % d)
call_nsupdate(d, op="delete")
# ask nsupdate to add entries as needed
for d in update_list:
if d.rpc or (not use_nsupdate and use_samba_tool):
if opts.verbose:
print("update (samba-tool): %s" % d)
call_samba_tool(d, zone=d.zone)
elif am_rodc:
if d.name.lower() == domain.lower():
if opts.verbose:
print("skip (rodc): %s" % d)
continue
if not d.type in [ 'A', 'AAAA' ]:
if opts.verbose:
print("update (rodc): %s" % d)
call_rodc_update(d)
else:
if opts.verbose:
print("update (nsupdate): %s" % d)
call_nsupdate(d)
else:
if opts.verbose:
print("update(nsupdate): %s" % d)
call_nsupdate(d)
if rebuild_cache:
print("Rebuilding cache at %s" % dns_update_cache)
(file_dir, file_name) = os.path.split(dns_update_cache)
(tmp_fd, tmpfile) = tempfile.mkstemp(dir=file_dir, prefix=file_name, suffix="XXXXXX")
wfile = os.fdopen(tmp_fd, 'a')
for d in dns_list:
if opts.verbose:
print("Adding %s to %s" % (str(d), file_name))
wfile.write(str(d)+"\n")
wfile.flush()
os.rename(tmpfile, dns_update_cache)
fcntl.lockf(cfile, fcntl.LOCK_UN)
# delete the ccache if we created it
if ccachename is not None:
os.unlink(ccachename)
if error_count != 0:
print("Failed update of %u entries" % error_count)
sys.exit(error_count)
|