summaryrefslogtreecommitdiff
path: root/source4/kdc/db-glue.c
blob: a54f8f59cf8bbbafd3069da96d558d844748dc24 (plain)
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
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
/*
   Unix SMB/CIFS implementation.

   Database Glue between Samba and the KDC

   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2005-2009
   Copyright (C) Simo Sorce <idra@samba.org> 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/>.
*/

#include "includes.h"
#include "system/time.h"
#include "../libds/common/flags.h"
#include "lib/ldb/include/ldb.h"
#include "librpc/gen_ndr/netlogon.h"
#include "libcli/security/security.h"
#include "auth/auth.h"
#include "auth/credentials/credentials.h"
#include "auth/auth_sam.h"
#include "../lib/util/util_ldb.h"
#include "dsdb/samdb/samdb.h"
#include "dsdb/common/util.h"
#include "librpc/ndr/libndr.h"
#include "librpc/gen_ndr/ndr_drsblobs.h"
#include "librpc/gen_ndr/lsa.h"
#include "libcli/auth/libcli_auth.h"
#include "param/param.h"
#include "../lib/crypto/md4.h"
#include "system/kerberos.h"
#include <hdb.h>
#include "kdc/samba_kdc.h"
#include "kdc/db-glue.h"

enum samba_kdc_ent_type
{ SAMBA_KDC_ENT_TYPE_CLIENT, SAMBA_KDC_ENT_TYPE_SERVER,
  SAMBA_KDC_ENT_TYPE_KRBTGT, SAMBA_KDC_ENT_TYPE_TRUST, SAMBA_KDC_ENT_TYPE_ANY };

enum trust_direction {
	UNKNOWN = 0,
	INBOUND = LSA_TRUST_DIRECTION_INBOUND,
	OUTBOUND = LSA_TRUST_DIRECTION_OUTBOUND
};

static const char *trust_attrs[] = {
	"trustPartner",
	"trustAuthIncoming",
	"trustAuthOutgoing",
	"whenCreated",
	"msDS-SupportedEncryptionTypes",
	"trustAttributes",
	"trustDirection",
	"trustType",
	NULL
};

static KerberosTime ldb_msg_find_krb5time_ldap_time(struct ldb_message *msg, const char *attr, KerberosTime default_val)
{
    const char *tmp;
    const char *gentime;
    struct tm tm;

    gentime = ldb_msg_find_attr_as_string(msg, attr, NULL);
    if (!gentime)
	return default_val;

    tmp = strptime(gentime, "%Y%m%d%H%M%SZ", &tm);
    if (tmp == NULL) {
	    return default_val;
    }

    return timegm(&tm);
}

static HDBFlags uf2HDBFlags(krb5_context context, int userAccountControl, enum samba_kdc_ent_type ent_type)
{
	HDBFlags flags = int2HDBFlags(0);

	/* we don't allow kadmin deletes */
	flags.immutable = 1;

	/* mark the principal as invalid to start with */
	flags.invalid = 1;

	flags.renewable = 1;

	/* All accounts are servers, but this may be disabled again in the caller */
	flags.server = 1;

	/* Account types - clear the invalid bit if it turns out to be valid */
	if (userAccountControl & UF_NORMAL_ACCOUNT) {
		if (ent_type == SAMBA_KDC_ENT_TYPE_CLIENT || ent_type == SAMBA_KDC_ENT_TYPE_ANY) {
			flags.client = 1;
		}
		flags.invalid = 0;
	}

	if (userAccountControl & UF_INTERDOMAIN_TRUST_ACCOUNT) {
		if (ent_type == SAMBA_KDC_ENT_TYPE_CLIENT || ent_type == SAMBA_KDC_ENT_TYPE_ANY) {
			flags.client = 1;
		}
		flags.invalid = 0;
	}
	if (userAccountControl & UF_WORKSTATION_TRUST_ACCOUNT) {
		if (ent_type == SAMBA_KDC_ENT_TYPE_CLIENT || ent_type == SAMBA_KDC_ENT_TYPE_ANY) {
			flags.client = 1;
		}
		flags.invalid = 0;
	}
	if (userAccountControl & UF_SERVER_TRUST_ACCOUNT) {
		if (ent_type == SAMBA_KDC_ENT_TYPE_CLIENT || ent_type == SAMBA_KDC_ENT_TYPE_ANY) {
			flags.client = 1;
		}
		flags.invalid = 0;
	}

	/* Not permitted to act as a client if disabled */
	if (userAccountControl & UF_ACCOUNTDISABLE) {
		flags.client = 0;
	}
	if (userAccountControl & UF_LOCKOUT) {
		flags.invalid = 1;
	}
/*
	if (userAccountControl & UF_PASSWORD_NOTREQD) {
		flags.invalid = 1;
	}
*/
/*
	UF_PASSWORD_CANT_CHANGE and UF_ENCRYPTED_TEXT_PASSWORD_ALLOWED are irrelevent
*/
	if (userAccountControl & UF_TEMP_DUPLICATE_ACCOUNT) {
		flags.invalid = 1;
	}

/* UF_DONT_EXPIRE_PASSWD and UF_USE_DES_KEY_ONLY handled in samba_kdc_message2entry() */

/*
	if (userAccountControl & UF_MNS_LOGON_ACCOUNT) {
		flags.invalid = 1;
	}
*/
	if (userAccountControl & UF_SMARTCARD_REQUIRED) {
		flags.require_hwauth = 1;
	}
	if (userAccountControl & UF_TRUSTED_FOR_DELEGATION) {
		flags.ok_as_delegate = 1;
	}
	if (!(userAccountControl & UF_NOT_DELEGATED)) {
		flags.forwardable = 1;
		flags.proxiable = 1;
	}

	if (userAccountControl & UF_DONT_REQUIRE_PREAUTH) {
		flags.require_preauth = 0;
	} else {
		flags.require_preauth = 1;

	}
	return flags;
}

static int samba_kdc_entry_destructor(struct samba_kdc_entry *p)
{
    hdb_entry_ex *entry_ex = p->entry_ex;
    free_hdb_entry(&entry_ex->entry);
    return 0;
}

static void samba_kdc_free_entry(krb5_context context, hdb_entry_ex *entry_ex)
{
	/* this function is called only from hdb_free_entry().
	 * Make sure we neutralize the destructor or we will
	 * get a double free later when hdb_free_entry() will
	 * try to call free_hdb_entry() */
	talloc_set_destructor(entry_ex->ctx, NULL);

	/* now proceed to free the talloc part */
	talloc_free(entry_ex->ctx);
}

static krb5_error_code samba_kdc_message2entry_keys(krb5_context context,
					      struct smb_iconv_convenience *iconv_convenience,
					      TALLOC_CTX *mem_ctx,
					      struct ldb_message *msg,
					      unsigned int userAccountControl,
					      hdb_entry_ex *entry_ex)
{
	krb5_error_code ret = 0;
	enum ndr_err_code ndr_err;
	struct samr_Password *hash;
	const struct ldb_val *sc_val;
	struct supplementalCredentialsBlob scb;
	struct supplementalCredentialsPackage *scpk = NULL;
	bool newer_keys = false;
	struct package_PrimaryKerberosBlob _pkb;
	struct package_PrimaryKerberosCtr3 *pkb3 = NULL;
	struct package_PrimaryKerberosCtr4 *pkb4 = NULL;
	uint32_t i;
	uint32_t allocated_keys = 0;

	entry_ex->entry.keys.val = NULL;
	entry_ex->entry.keys.len = 0;

	entry_ex->entry.kvno = ldb_msg_find_attr_as_int(msg, "msDS-KeyVersionNumber", 0);

	/* Get keys from the db */

	hash = samdb_result_hash(mem_ctx, msg, "unicodePwd");
	sc_val = ldb_msg_find_ldb_val(msg, "supplementalCredentials");

	/* unicodePwd for enctype 0x17 (23) if present */
	if (hash) {
		allocated_keys++;
	}

	/* supplementalCredentials if present */
	if (sc_val) {
		ndr_err = ndr_pull_struct_blob_all(sc_val, mem_ctx, iconv_convenience, &scb,
						   (ndr_pull_flags_fn_t)ndr_pull_supplementalCredentialsBlob);
		if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
			dump_data(0, sc_val->data, sc_val->length);
			ret = EINVAL;
			goto out;
		}

		if (scb.sub.signature != SUPPLEMENTAL_CREDENTIALS_SIGNATURE) {
			NDR_PRINT_DEBUG(supplementalCredentialsBlob, &scb);
			ret = EINVAL;
			goto out;
		}

		for (i=0; i < scb.sub.num_packages; i++) {
			if (strcmp("Primary:Kerberos-Newer-Keys", scb.sub.packages[i].name) == 0) {
				scpk = &scb.sub.packages[i];
				if (!scpk->data || !scpk->data[0]) {
					scpk = NULL;
					continue;
				}
				newer_keys = true;
				break;
			} else if (strcmp("Primary:Kerberos", scb.sub.packages[i].name) == 0) {
				scpk = &scb.sub.packages[i];
				if (!scpk->data || !scpk->data[0]) {
					scpk = NULL;
				}
				/*
				 * we don't break here in hope to find
				 * a Kerberos-Newer-Keys package
				 */
			}
		}
	}
	/*
	 * Primary:Kerberos-Newer-Keys or Primary:Kerberos element
	 * of supplementalCredentials
	 */
	if (scpk) {
		DATA_BLOB blob;

		blob = strhex_to_data_blob(mem_ctx, scpk->data);
		if (!blob.data) {
			ret = ENOMEM;
			goto out;
		}

		/* we cannot use ndr_pull_struct_blob_all() here, as w2k and w2k3 add padding bytes */
		ndr_err = ndr_pull_struct_blob(&blob, mem_ctx, iconv_convenience, &_pkb,
					       (ndr_pull_flags_fn_t)ndr_pull_package_PrimaryKerberosBlob);
		if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
			ret = EINVAL;
			krb5_set_error_message(context, ret, "samba_kdc_message2entry_keys: could not parse package_PrimaryKerberosBlob");
			krb5_warnx(context, "samba_kdc_message2entry_keys: could not parse package_PrimaryKerberosBlob");
			goto out;
		}

		if (newer_keys && _pkb.version != 4) {
			ret = EINVAL;
			krb5_set_error_message(context, ret, "samba_kdc_message2entry_keys: Primary:Kerberos-Newer-Keys not version 4");
			krb5_warnx(context, "samba_kdc_message2entry_keys: Primary:Kerberos-Newer-Keys not version 4");
			goto out;
		}

		if (!newer_keys && _pkb.version != 3) {
			ret = EINVAL;
			krb5_set_error_message(context, ret, "samba_kdc_message2entry_keys: could not parse Primary:Kerberos not version 3");
			krb5_warnx(context, "samba_kdc_message2entry_keys: could not parse Primary:Kerberos not version 3");
			goto out;
		}

		if (_pkb.version == 4) {
			pkb4 = &_pkb.ctr.ctr4;
			allocated_keys += pkb4->num_keys;
		} else if (_pkb.version == 3) {
			pkb3 = &_pkb.ctr.ctr3;
			allocated_keys += pkb3->num_keys;
		}
	}

	if (allocated_keys == 0) {
		/* oh, no password.  Apparently (comment in
		 * hdb-ldap.c) this violates the ASN.1, but this
		 * allows an entry with no keys (yet). */
		return 0;
	}

	/* allocate space to decode into */
	entry_ex->entry.keys.len = 0;
	entry_ex->entry.keys.val = calloc(allocated_keys, sizeof(Key));
	if (entry_ex->entry.keys.val == NULL) {
		ret = ENOMEM;
		goto out;
	}

	if (hash && !(userAccountControl & UF_USE_DES_KEY_ONLY)) {
		Key key;

		key.mkvno = 0;
		key.salt = NULL; /* No salt for this enc type */

		ret = krb5_keyblock_init(context,
					 ENCTYPE_ARCFOUR_HMAC,
					 hash->hash, sizeof(hash->hash),
					 &key.key);
		if (ret) {
			goto out;
		}

		entry_ex->entry.keys.val[entry_ex->entry.keys.len] = key;
		entry_ex->entry.keys.len++;
	}

	if (pkb4) {
		for (i=0; i < pkb4->num_keys; i++) {
			bool use = true;
			Key key;

			if (!pkb4->keys[i].value) continue;

			if (userAccountControl & UF_USE_DES_KEY_ONLY) {
				switch (pkb4->keys[i].keytype) {
				case ENCTYPE_DES_CBC_CRC:
				case ENCTYPE_DES_CBC_MD5:
					break;
				default:
					use = false;
					break;
				}
			}

			if (!use) continue;

			key.mkvno = 0;
			key.salt = NULL;

			if (pkb4->salt.string) {
				DATA_BLOB salt;

				salt = data_blob_string_const(pkb4->salt.string);

				key.salt = calloc(1, sizeof(*key.salt));
				if (key.salt == NULL) {
					ret = ENOMEM;
					goto out;
				}

				key.salt->type = hdb_pw_salt;

				ret = krb5_data_copy(&key.salt->salt, salt.data, salt.length);
				if (ret) {
					free(key.salt);
					key.salt = NULL;
					goto out;
				}
			}

			/* TODO: maybe pass the iteration_count somehow... */

			ret = krb5_keyblock_init(context,
						 pkb4->keys[i].keytype,
						 pkb4->keys[i].value->data,
						 pkb4->keys[i].value->length,
						 &key.key);
			if (ret == KRB5_PROG_ETYPE_NOSUPP) {
				DEBUG(2,("Unsupported keytype ignored - type %u\n",
					 pkb4->keys[i].keytype));
				ret = 0;
				continue;
			}
			if (ret) {
				if (key.salt) {
					free_Salt(key.salt);
					free(key.salt);
					key.salt = NULL;
				}
				goto out;
			}

			entry_ex->entry.keys.val[entry_ex->entry.keys.len] = key;
			entry_ex->entry.keys.len++;
		}
	} else if (pkb3) {
		for (i=0; i < pkb3->num_keys; i++) {
			bool use = true;
			Key key;

			if (!pkb3->keys[i].value) continue;

			if (userAccountControl & UF_USE_DES_KEY_ONLY) {
				switch (pkb3->keys[i].keytype) {
				case ENCTYPE_DES_CBC_CRC:
				case ENCTYPE_DES_CBC_MD5:
					break;
				default:
					use = false;
					break;
				}
			}

			if (!use) continue;

			key.mkvno = 0;
			key.salt = NULL;

			if (pkb3->salt.string) {
				DATA_BLOB salt;

				salt = data_blob_string_const(pkb3->salt.string);

				key.salt = calloc(1, sizeof(*key.salt));
				if (key.salt == NULL) {
					ret = ENOMEM;
					goto out;
				}

				key.salt->type = hdb_pw_salt;

				ret = krb5_data_copy(&key.salt->salt, salt.data, salt.length);
				if (ret) {
					free(key.salt);
					key.salt = NULL;
					goto out;
				}
			}

			ret = krb5_keyblock_init(context,
						 pkb3->keys[i].keytype,
						 pkb3->keys[i].value->data,
						 pkb3->keys[i].value->length,
						 &key.key);
			if (ret) {
				if (key.salt) {
					free_Salt(key.salt);
					free(key.salt);
					key.salt = NULL;
				}
				goto out;
			}

			entry_ex->entry.keys.val[entry_ex->entry.keys.len] = key;
			entry_ex->entry.keys.len++;
		}
	}

out:
	if (ret != 0) {
		entry_ex->entry.keys.len = 0;
	}
	if (entry_ex->entry.keys.len == 0 && entry_ex->entry.keys.val) {
		free(entry_ex->entry.keys.val);
		entry_ex->entry.keys.val = NULL;
	}
	return ret;
}

/*
 * Construct an hdb_entry from a directory entry.
 */
static krb5_error_code samba_kdc_message2entry(krb5_context context,
					 struct samba_kdc_db_context *kdc_db_ctx,
					 TALLOC_CTX *mem_ctx, krb5_const_principal principal,
					 enum samba_kdc_ent_type ent_type,
					 struct ldb_dn *realm_dn,
					 struct ldb_message *msg,
					 hdb_entry_ex *entry_ex)
{
	struct loadparm_context *lp_ctx = kdc_db_ctx->lp_ctx;
	unsigned int userAccountControl;
	int i;
	krb5_error_code ret = 0;
	krb5_boolean is_computer = FALSE;
	char *realm = strupper_talloc(mem_ctx, lp_realm(lp_ctx));

	struct samba_kdc_entry *p;
	NTTIME acct_expiry;
	NTSTATUS status;

	uint32_t rid;
	struct ldb_message_element *objectclasses;
	struct ldb_val computer_val;
	const char *samAccountName = ldb_msg_find_attr_as_string(msg, "samAccountName", NULL);
	computer_val.data = discard_const_p(uint8_t,"computer");
	computer_val.length = strlen((const char *)computer_val.data);

	if (!samAccountName) {
		ret = ENOENT;
		krb5_set_error_message(context, ret, "samba_kdc_message2entry: no samAccountName present");
		goto out;
	}

	objectclasses = ldb_msg_find_element(msg, "objectClass");

	if (objectclasses && ldb_msg_find_val(objectclasses, &computer_val)) {
		is_computer = TRUE;
	}

	memset(entry_ex, 0, sizeof(*entry_ex));

	if (!realm) {
		ret = ENOMEM;
		krb5_set_error_message(context, ret, "talloc_strdup: out of memory");
		goto out;
	}

	p = talloc(mem_ctx, struct samba_kdc_entry);
	if (!p) {
		ret = ENOMEM;
		goto out;
	}

	p->kdc_db_ctx = kdc_db_ctx;
	p->entry_ex = entry_ex;
	p->realm_dn = talloc_reference(p, realm_dn);
	if (!p->realm_dn) {
		ret = ENOMEM;
		goto out;
	}

	talloc_set_destructor(p, samba_kdc_entry_destructor);

	/* make sure we do not have bogus data in there */
	memset(&entry_ex->entry, 0, sizeof(hdb_entry));

	entry_ex->ctx = p;
	entry_ex->free_entry = samba_kdc_free_entry;

	userAccountControl = ldb_msg_find_attr_as_uint(msg, "userAccountControl", 0);


	entry_ex->entry.principal = malloc(sizeof(*(entry_ex->entry.principal)));
	if (ent_type == SAMBA_KDC_ENT_TYPE_ANY && principal == NULL) {
		krb5_make_principal(context, &entry_ex->entry.principal, realm, samAccountName, NULL);
	} else {
		ret = copy_Principal(principal, entry_ex->entry.principal);
		if (ret) {
			krb5_clear_error_message(context);
			goto out;
		}

		/* While we have copied the client principal, tests
		 * show that Win2k3 returns the 'corrected' realm, not
		 * the client-specified realm.  This code attempts to
		 * replace the client principal's realm with the one
		 * we determine from our records */

		/* this has to be with malloc() */
		krb5_principal_set_realm(context, entry_ex->entry.principal, realm);
	}

	/* First try and figure out the flags based on the userAccountControl */
	entry_ex->entry.flags = uf2HDBFlags(context, userAccountControl, ent_type);

	/* Windows 2008 seems to enforce this (very sensible) rule by
	 * default - don't allow offline attacks on a user's password
	 * by asking for a ticket to them as a service (encrypted with
	 * their probably patheticly insecure password) */

	if (entry_ex->entry.flags.server
	    && lp_parm_bool(lp_ctx, NULL, "kdc", "require spn for service", true)) {
		if (!is_computer && !ldb_msg_find_attr_as_string(msg, "servicePrincipalName", NULL)) {
			entry_ex->entry.flags.server = 0;
		}
	}

	{
		/* These (created_by, modified_by) parts of the entry are not relevant for Samba4's use
		 * of the Heimdal KDC.  They are stored in a the traditional
		 * DB for audit purposes, and still form part of the structure
		 * we must return */

		/* use 'whenCreated' */
		entry_ex->entry.created_by.time = ldb_msg_find_krb5time_ldap_time(msg, "whenCreated", 0);
		/* use 'kadmin' for now (needed by mit_samba) */
		krb5_make_principal(context,
				    &entry_ex->entry.created_by.principal,
				    realm, "kadmin", NULL);

		entry_ex->entry.modified_by = (Event *) malloc(sizeof(Event));
		if (entry_ex->entry.modified_by == NULL) {
			ret = ENOMEM;
			krb5_set_error_message(context, ret, "malloc: out of memory");
			goto out;
		}

		/* use 'whenChanged' */
		entry_ex->entry.modified_by->time = ldb_msg_find_krb5time_ldap_time(msg, "whenChanged", 0);
		/* use 'kadmin' for now (needed by mit_samba) */
		krb5_make_principal(context,
				    &entry_ex->entry.modified_by->principal,
				    realm, "kadmin", NULL);
	}


	/* The lack of password controls etc applies to krbtgt by
	 * virtue of being that particular RID */
	status = dom_sid_split_rid(NULL, samdb_result_dom_sid(mem_ctx, msg, "objectSid"), NULL, &rid);

	if (!NT_STATUS_IS_OK(status)) {
		ret = EINVAL;
		goto out;
	}

	if (rid == DOMAIN_RID_KRBTGT) {
		entry_ex->entry.valid_end = NULL;
		entry_ex->entry.pw_end = NULL;

		entry_ex->entry.flags.invalid = 0;
		entry_ex->entry.flags.server = 1;

		/* Don't mark all requests for the krbtgt/realm as
		 * 'change password', as otherwise we could get into
		 * trouble, and not enforce the password expirty.
		 * Instead, only do it when request is for the kpasswd service */
		if (ent_type == SAMBA_KDC_ENT_TYPE_SERVER
		    && principal->name.name_string.len == 2
		    && (strcmp(principal->name.name_string.val[0], "kadmin") == 0)
		    && (strcmp(principal->name.name_string.val[1], "changepw") == 0)
		    && lp_is_my_domain_or_realm(lp_ctx, principal->realm)) {
			entry_ex->entry.flags.change_pw = 1;
		}
		entry_ex->entry.flags.client = 0;
		entry_ex->entry.flags.forwardable = 1;
		entry_ex->entry.flags.ok_as_delegate = 1;
	} else if (entry_ex->entry.flags.server && ent_type == SAMBA_KDC_ENT_TYPE_SERVER) {
		/* The account/password expiry only applies when the account is used as a
		 * client (ie password login), not when used as a server */

		/* Make very well sure we don't use this for a client,
		 * it could bypass the password restrictions */
		entry_ex->entry.flags.client = 0;

		entry_ex->entry.valid_end = NULL;
		entry_ex->entry.pw_end = NULL;

	} else {
		NTTIME must_change_time
			= samdb_result_force_password_change(kdc_db_ctx->samdb, mem_ctx,
							     realm_dn, msg);
		if (must_change_time == 0x7FFFFFFFFFFFFFFFULL) {
			entry_ex->entry.pw_end = NULL;
		} else {
			entry_ex->entry.pw_end = malloc(sizeof(*entry_ex->entry.pw_end));
			if (entry_ex->entry.pw_end == NULL) {
				ret = ENOMEM;
				goto out;
			}
			*entry_ex->entry.pw_end = nt_time_to_unix(must_change_time);
		}

		acct_expiry = samdb_result_account_expires(msg);
		if (acct_expiry == 0x7FFFFFFFFFFFFFFFULL) {
			entry_ex->entry.valid_end = NULL;
		} else {
			entry_ex->entry.valid_end = malloc(sizeof(*entry_ex->entry.valid_end));
			if (entry_ex->entry.valid_end == NULL) {
				ret = ENOMEM;
				goto out;
			}
			*entry_ex->entry.valid_end = nt_time_to_unix(acct_expiry);
		}
	}

	entry_ex->entry.valid_start = NULL;

	entry_ex->entry.max_life = NULL;

	entry_ex->entry.max_renew = NULL;

	entry_ex->entry.generation = NULL;

	/* Get keys from the db */
	ret = samba_kdc_message2entry_keys(context, p->kdc_db_ctx->ic_ctx, p,
					    msg, userAccountControl, entry_ex);
	if (ret) {
		/* Could be bougus data in the entry, or out of memory */
		goto out;
	}

	entry_ex->entry.etypes = malloc(sizeof(*(entry_ex->entry.etypes)));
	if (entry_ex->entry.etypes == NULL) {
		krb5_clear_error_message(context);
		ret = ENOMEM;
		goto out;
	}
	entry_ex->entry.etypes->len = entry_ex->entry.keys.len;
	entry_ex->entry.etypes->val = calloc(entry_ex->entry.etypes->len, sizeof(int));
	if (entry_ex->entry.etypes->val == NULL) {
		krb5_clear_error_message(context);
		ret = ENOMEM;
		goto out;
	}
	for (i=0; i < entry_ex->entry.etypes->len; i++) {
		entry_ex->entry.etypes->val[i] = entry_ex->entry.keys.val[i].key.keytype;
	}


	p->msg = talloc_steal(p, msg);

out:
	if (ret != 0) {
		/* This doesn't free ent itself, that is for the eventual caller to do */
		hdb_free_entry(context, entry_ex);
	} else {
		talloc_steal(kdc_db_ctx, entry_ex->ctx);
	}

	return ret;
}

/*
 * Construct an hdb_entry from a directory entry.
 */
static krb5_error_code samba_kdc_trust_message2entry(krb5_context context,
					       struct samba_kdc_db_context *kdc_db_ctx,
					       TALLOC_CTX *mem_ctx, krb5_const_principal principal,
					       enum trust_direction direction,
					       struct ldb_dn *realm_dn,
					       struct ldb_message *msg,
					       hdb_entry_ex *entry_ex)
{
	struct loadparm_context *lp_ctx = kdc_db_ctx->lp_ctx;
	const char *dnsdomain;
	char *realm = strupper_talloc(mem_ctx, lp_realm(lp_ctx));
	DATA_BLOB password_utf16;
	struct samr_Password password_hash;
	const struct ldb_val *password_val;
	struct trustAuthInOutBlob password_blob;
	struct samba_kdc_entry *p;

	enum ndr_err_code ndr_err;
	int i, ret, trust_direction_flags;

	p = talloc(mem_ctx, struct samba_kdc_entry);
	if (!p) {
		ret = ENOMEM;
		goto out;
	}

	p->kdc_db_ctx = kdc_db_ctx;
	p->entry_ex = entry_ex;
	p->realm_dn = realm_dn;

	talloc_set_destructor(p, samba_kdc_entry_destructor);

	/* make sure we do not have bogus data in there */
	memset(&entry_ex->entry, 0, sizeof(hdb_entry));

	entry_ex->ctx = p;
	entry_ex->free_entry = samba_kdc_free_entry;

	/* use 'whenCreated' */
	entry_ex->entry.created_by.time = ldb_msg_find_krb5time_ldap_time(msg, "whenCreated", 0);
	/* use 'kadmin' for now (needed by mit_samba) */
	krb5_make_principal(context,
			    &entry_ex->entry.created_by.principal,
			    realm, "kadmin", NULL);

	entry_ex->entry.valid_start = NULL;

	trust_direction_flags = ldb_msg_find_attr_as_int(msg, "trustDirection", 0);

	if (direction == INBOUND) {
		password_val = ldb_msg_find_ldb_val(msg, "trustAuthIncoming");

	} else { /* OUTBOUND */
		dnsdomain = ldb_msg_find_attr_as_string(msg, "trustPartner", NULL);
		/* replace realm */
		talloc_free(realm);
		realm = strupper_talloc(mem_ctx, dnsdomain);
		password_val = ldb_msg_find_ldb_val(msg, "trustAuthOutgoing");
	}

	if (!password_val || !(trust_direction_flags & direction)) {
		ret = ENOENT;
		goto out;
	}

	ndr_err = ndr_pull_struct_blob(password_val, mem_ctx, p->kdc_db_ctx->ic_ctx, &password_blob,
					   (ndr_pull_flags_fn_t)ndr_pull_trustAuthInOutBlob);
	if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
		ret = EINVAL;
		goto out;
	}

	entry_ex->entry.kvno = -1;
	for (i=0; i < password_blob.count; i++) {
		if (password_blob.current->array[i].AuthType == TRUST_AUTH_TYPE_VERSION) {
			entry_ex->entry.kvno = password_blob.current->array[i].AuthInfo.version.version;
		}
	}

	for (i=0; i < password_blob.count; i++) {
		if (password_blob.current->array[i].AuthType == TRUST_AUTH_TYPE_CLEAR) {
			password_utf16 = data_blob_const(password_blob.current->array[i].AuthInfo.clear.password,
							 password_blob.current->array[i].AuthInfo.clear.size);
			/* In the future, generate all sorts of
			 * hashes, but for now we can't safely convert
			 * the random strings windows uses into
			 * utf8 */

			/* but as it is utf16 already, we can get the NT password/arcfour-hmac-md5 key */
			mdfour(password_hash.hash, password_utf16.data, password_utf16.length);
			break;
		} else if (password_blob.current->array[i].AuthType == TRUST_AUTH_TYPE_NT4OWF) {
			password_hash = password_blob.current->array[i].AuthInfo.nt4owf.password;
			break;
		}
	}

	if (i < password_blob.count) {
		Key key;
		/* Must have found a cleartext or MD4 password */
		entry_ex->entry.keys.val = calloc(1, sizeof(Key));

		key.mkvno = 0;
		key.salt = NULL; /* No salt for this enc type */

		if (entry_ex->entry.keys.val == NULL) {
			ret = ENOMEM;
			goto out;
		}

		ret = krb5_keyblock_init(context,
					 ENCTYPE_ARCFOUR_HMAC,
					 password_hash.hash, sizeof(password_hash.hash),
					 &key.key);

		entry_ex->entry.keys.val[entry_ex->entry.keys.len] = key;
		entry_ex->entry.keys.len++;
	}

	entry_ex->entry.principal = malloc(sizeof(*(entry_ex->entry.principal)));

	ret = copy_Principal(principal, entry_ex->entry.principal);
	if (ret) {
		krb5_clear_error_message(context);
		goto out;
	}

	/* While we have copied the client principal, tests
	 * show that Win2k3 returns the 'corrected' realm, not
	 * the client-specified realm.  This code attempts to
	 * replace the client principal's realm with the one
	 * we determine from our records */

	krb5_principal_set_realm(context, entry_ex->entry.principal, realm);
	entry_ex->entry.flags = int2HDBFlags(0);
	entry_ex->entry.flags.immutable = 1;
	entry_ex->entry.flags.invalid = 0;
	entry_ex->entry.flags.server = 1;
	entry_ex->entry.flags.require_preauth = 1;

	entry_ex->entry.pw_end = NULL;

	entry_ex->entry.max_life = NULL;

	entry_ex->entry.max_renew = NULL;

	entry_ex->entry.generation = NULL;

	entry_ex->entry.etypes = malloc(sizeof(*(entry_ex->entry.etypes)));
	if (entry_ex->entry.etypes == NULL) {
		krb5_clear_error_message(context);
		ret = ENOMEM;
		goto out;
	}
	entry_ex->entry.etypes->len = entry_ex->entry.keys.len;
	entry_ex->entry.etypes->val = calloc(entry_ex->entry.etypes->len, sizeof(int));
	if (entry_ex->entry.etypes->val == NULL) {
		krb5_clear_error_message(context);
		ret = ENOMEM;
		goto out;
	}
	for (i=0; i < entry_ex->entry.etypes->len; i++) {
		entry_ex->entry.etypes->val[i] = entry_ex->entry.keys.val[i].key.keytype;
	}


	p->msg = talloc_steal(p, msg);

out:
	if (ret != 0) {
		/* This doesn't free ent itself, that is for the eventual caller to do */
		hdb_free_entry(context, entry_ex);
	} else {
		talloc_steal(kdc_db_ctx, entry_ex->ctx);
	}

	return ret;

}

static krb5_error_code samba_kdc_lookup_trust(krb5_context context, struct ldb_context *ldb_ctx,
					TALLOC_CTX *mem_ctx,
					const char *realm,
					struct ldb_dn *realm_dn,
					struct ldb_message **pmsg)
{
	int lret;
	krb5_error_code ret;
	char *filter = NULL;
	const char * const *attrs = trust_attrs;

	struct ldb_result *res = NULL;
	filter = talloc_asprintf(mem_ctx, "(&(objectClass=trustedDomain)(|(flatname=%s)(trustPartner=%s)))", realm, realm);

	if (!filter) {
		ret = ENOMEM;
		krb5_set_error_message(context, ret, "talloc_asprintf: out of memory");
		return ret;
	}

	lret = ldb_search(ldb_ctx, mem_ctx, &res,
			  ldb_get_default_basedn(ldb_ctx),
			  LDB_SCOPE_SUBTREE, attrs, "%s", filter);
	if (lret != LDB_SUCCESS) {
		DEBUG(3, ("Failed to search for %s: %s\n", filter, ldb_errstring(ldb_ctx)));
		return HDB_ERR_NOENTRY;
	} else if (res->count == 0 || res->count > 1) {
		DEBUG(3, ("Failed find a single entry for %s: got %d\n", filter, res->count));
		talloc_free(res);
		return HDB_ERR_NOENTRY;
	}
	talloc_steal(mem_ctx, res->msgs);
	*pmsg = res->msgs[0];
	talloc_free(res);
	return 0;
}

static krb5_error_code samba_kdc_lookup_client(krb5_context context,
						struct samba_kdc_db_context *kdc_db_ctx,
						TALLOC_CTX *mem_ctx,
						krb5_const_principal principal,
						const char **attrs,
						struct ldb_dn **realm_dn,
						struct ldb_message **msg) {
	NTSTATUS nt_status;
	char *principal_string;
	krb5_error_code ret;

	ret = krb5_unparse_name(context, principal, &principal_string);

	if (ret != 0) {
		return ret;
	}

	nt_status = sam_get_results_principal(kdc_db_ctx->samdb,
					      mem_ctx, principal_string, attrs,
					      realm_dn, msg);
	free(principal_string);
	if (NT_STATUS_EQUAL(nt_status, NT_STATUS_NO_SUCH_USER)) {
		return HDB_ERR_NOENTRY;
	} else if (NT_STATUS_EQUAL(nt_status, NT_STATUS_NO_MEMORY)) {
		return ENOMEM;
	} else if (!NT_STATUS_IS_OK(nt_status)) {
		return EINVAL;
	}

	return ret;
}

static krb5_error_code samba_kdc_fetch_client(krb5_context context,
					       struct samba_kdc_db_context *kdc_db_ctx,
					       TALLOC_CTX *mem_ctx,
					       krb5_const_principal principal,
					       hdb_entry_ex *entry_ex) {
	struct ldb_dn *realm_dn;
	krb5_error_code ret;
	struct ldb_message *msg = NULL;

	ret = samba_kdc_lookup_client(context, kdc_db_ctx,
				       mem_ctx, principal, user_attrs,
				       &realm_dn, &msg);
	if (ret != 0) {
		return ret;
	}

	ret = samba_kdc_message2entry(context, kdc_db_ctx, mem_ctx,
				       principal, SAMBA_KDC_ENT_TYPE_CLIENT,
				       realm_dn, msg, entry_ex);
	return ret;
}

static krb5_error_code samba_kdc_fetch_krbtgt(krb5_context context,
					struct samba_kdc_db_context *kdc_db_ctx,
					TALLOC_CTX *mem_ctx,
					krb5_const_principal principal,
					hdb_entry_ex *entry_ex)
{
	struct loadparm_context *lp_ctx = kdc_db_ctx->lp_ctx;
	krb5_error_code ret;
	struct ldb_message *msg = NULL;
	struct ldb_dn *realm_dn = ldb_get_default_basedn(kdc_db_ctx->samdb);
	const char *realm;

	krb5_principal alloc_principal = NULL;
	if (principal->name.name_string.len != 2
	    || (strcmp(principal->name.name_string.val[0], KRB5_TGS_NAME) != 0)) {
		/* Not a krbtgt */
		return HDB_ERR_NOENTRY;
	}

	/* krbtgt case.  Either us or a trusted realm */

	if (lp_is_my_domain_or_realm(lp_ctx, principal->realm)
	    && lp_is_my_domain_or_realm(lp_ctx, principal->name.name_string.val[1])) {
		/* us */
 		/* Cludge, cludge cludge.  If the realm part of krbtgt/realm,
 		 * is in our db, then direct the caller at our primary
 		 * krbtgt */

		int lret;
		char *realm_fixed;

		lret = dsdb_search_one(kdc_db_ctx->samdb, mem_ctx,
				       &msg, realm_dn, LDB_SCOPE_SUBTREE,
				       krbtgt_attrs,
				       DSDB_SEARCH_SHOW_EXTENDED_DN,
				       "(&(objectClass=user)(samAccountName=krbtgt))");
		if (lret == LDB_ERR_NO_SUCH_OBJECT) {
			krb5_warnx(context, "samba_kdc_fetch: could not find own KRBTGT in DB!");
			krb5_set_error_message(context, HDB_ERR_NOENTRY, "samba_kdc_fetch: could not find own KRBTGT in DB!");
			return HDB_ERR_NOENTRY;
		} else if (lret != LDB_SUCCESS) {
			krb5_warnx(context, "samba_kdc_fetch: could not find own KRBTGT in DB: %s", ldb_errstring(kdc_db_ctx->samdb));
			krb5_set_error_message(context, HDB_ERR_NOENTRY, "samba_kdc_fetch: could not find own KRBTGT in DB: %s", ldb_errstring(kdc_db_ctx->samdb));
			return HDB_ERR_NOENTRY;
		}

 		realm_fixed = strupper_talloc(mem_ctx, lp_realm(lp_ctx));
 		if (!realm_fixed) {
			ret = ENOMEM;
 			krb5_set_error_message(context, ret, "strupper_talloc: out of memory");
 			return ret;
 		}

 		ret = krb5_copy_principal(context, principal, &alloc_principal);
 		if (ret) {
 			return ret;
 		}

 		free(alloc_principal->name.name_string.val[1]);
		alloc_principal->name.name_string.val[1] = strdup(realm_fixed);
 		talloc_free(realm_fixed);
 		if (!alloc_principal->name.name_string.val[1]) {
			ret = ENOMEM;
 			krb5_set_error_message(context, ret, "samba_kdc_fetch: strdup() failed!");
 			return ret;
 		}
 		principal = alloc_principal;

		ret = samba_kdc_message2entry(context, kdc_db_ctx, mem_ctx,
					principal, SAMBA_KDC_ENT_TYPE_KRBTGT,
					realm_dn, msg, entry_ex);
		if (ret != 0) {
			krb5_warnx(context, "samba_kdc_fetch: self krbtgt message2entry failed");
		}
		return ret;

	} else {
		enum trust_direction direction = UNKNOWN;

		/* Either an inbound or outbound trust */

		if (strcasecmp(lp_realm(lp_ctx), principal->realm) == 0) {
			/* look for inbound trust */
			direction = INBOUND;
			realm = principal->name.name_string.val[1];
		}

		if (strcasecmp(lp_realm(lp_ctx), principal->name.name_string.val[1]) == 0) {
			/* look for outbound trust */
			direction = OUTBOUND;
			realm = principal->realm;
		}

		/* Trusted domains are under CN=system */

		ret = samba_kdc_lookup_trust(context, kdc_db_ctx->samdb,
				       mem_ctx,
				       realm, realm_dn, &msg);

		if (ret != 0) {
			krb5_warnx(context, "samba_kdc_fetch: could not find principal in DB");
			krb5_set_error_message(context, ret, "samba_kdc_fetch: could not find principal in DB");
			return ret;
		}

		ret = samba_kdc_trust_message2entry(context, kdc_db_ctx, mem_ctx,
					      principal, direction,
					      realm_dn, msg, entry_ex);
		if (ret != 0) {
			krb5_warnx(context, "samba_kdc_fetch: trust_message2entry failed");
		}
		return ret;


		/* we should lookup trusted domains */
		return HDB_ERR_NOENTRY;
	}

}

static krb5_error_code samba_kdc_lookup_server(krb5_context context,
						struct samba_kdc_db_context *kdc_db_ctx,
						TALLOC_CTX *mem_ctx,
						krb5_const_principal principal,
						const char **attrs,
						struct ldb_dn **realm_dn,
						struct ldb_message **msg)
{
	krb5_error_code ret;
	const char *realm;
	if (principal->name.name_string.len >= 2) {
		/* 'normal server' case */
		int ldb_ret;
		NTSTATUS nt_status;
		struct ldb_dn *user_dn;
		char *principal_string;

		ret = krb5_unparse_name_flags(context, principal,
					      KRB5_PRINCIPAL_UNPARSE_NO_REALM,
					      &principal_string);
		if (ret != 0) {
			return ret;
		}

		/* At this point we may find the host is known to be
		 * in a different realm, so we should generate a
		 * referral instead */
		nt_status = crack_service_principal_name(kdc_db_ctx->samdb,
							 mem_ctx, principal_string,
							 &user_dn, realm_dn);
		free(principal_string);

		if (!NT_STATUS_IS_OK(nt_status)) {
			return HDB_ERR_NOENTRY;
		}

		ldb_ret = dsdb_search_one(kdc_db_ctx->samdb,
					  mem_ctx,
					  msg, user_dn, LDB_SCOPE_BASE,
					  attrs, DSDB_SEARCH_SHOW_EXTENDED_DN, "(objectClass=*)");
		if (ldb_ret != LDB_SUCCESS) {
			return HDB_ERR_NOENTRY;
		}

	} else {
		int lret;
		char *filter = NULL;
		char *short_princ;
		/* server as client principal case, but we must not lookup userPrincipalNames */
		*realm_dn = ldb_get_default_basedn(kdc_db_ctx->samdb);
		realm = krb5_principal_get_realm(context, principal);

		/* TODO: Check if it is our realm, otherwise give referall */

		ret = krb5_unparse_name_flags(context, principal,  KRB5_PRINCIPAL_UNPARSE_NO_REALM, &short_princ);

		if (ret != 0) {
			krb5_set_error_message(context, ret, "samba_kdc_lookup_principal: could not parse principal");
			krb5_warnx(context, "samba_kdc_lookup_principal: could not parse principal");
			return ret;
		}

		lret = dsdb_search_one(kdc_db_ctx->samdb, mem_ctx, msg,
				       *realm_dn, LDB_SCOPE_SUBTREE,
				       attrs,
				       DSDB_SEARCH_SHOW_EXTENDED_DN,
				       "(&(objectClass=user)(samAccountName=%s))",
				       ldb_binary_encode_string(mem_ctx, short_princ));
		free(short_princ);
		if (lret == LDB_ERR_NO_SUCH_OBJECT) {
			DEBUG(3, ("Failed find a entry for %s\n", filter));
			return HDB_ERR_NOENTRY;
		}
		if (lret != LDB_SUCCESS) {
			DEBUG(3, ("Failed single search for for %s - %s\n",
				  filter, ldb_errstring(kdc_db_ctx->samdb)));
			return HDB_ERR_NOENTRY;
		}
	}

	return 0;
}

static krb5_error_code samba_kdc_fetch_server(krb5_context context,
					       struct samba_kdc_db_context *kdc_db_ctx,
					       TALLOC_CTX *mem_ctx,
					       krb5_const_principal principal,
					       hdb_entry_ex *entry_ex)
{
	krb5_error_code ret;
	struct ldb_dn *realm_dn;
	struct ldb_message *msg;

	ret = samba_kdc_lookup_server(context, kdc_db_ctx, mem_ctx, principal,
				       server_attrs, &realm_dn, &msg);
	if (ret != 0) {
		return ret;
	}

	ret = samba_kdc_message2entry(context, kdc_db_ctx, mem_ctx,
				principal, SAMBA_KDC_ENT_TYPE_SERVER,
				realm_dn, msg, entry_ex);
	if (ret != 0) {
		krb5_warnx(context, "samba_kdc_fetch: message2entry failed");
	}

	return ret;
}

krb5_error_code samba_kdc_fetch(krb5_context context,
				struct samba_kdc_db_context *kdc_db_ctx,
				krb5_const_principal principal,
				unsigned flags,
				hdb_entry_ex *entry_ex)
{
	krb5_error_code ret = HDB_ERR_NOENTRY;
	TALLOC_CTX *mem_ctx = talloc_named(kdc_db_ctx, 0, "samba_kdc_fetch context");

	if (!mem_ctx) {
		ret = ENOMEM;
		krb5_set_error_message(context, ret, "samba_kdc_fetch: talloc_named() failed!");
		return ret;
	}

	if (flags & HDB_F_GET_CLIENT) {
		ret = samba_kdc_fetch_client(context, kdc_db_ctx, mem_ctx, principal, entry_ex);
		if (ret != HDB_ERR_NOENTRY) goto done;
	}
	if (flags & HDB_F_GET_SERVER) {
		/* krbtgt fits into this situation for trusted realms, and for resolving different versions of our own realm name */
		ret = samba_kdc_fetch_krbtgt(context, kdc_db_ctx, mem_ctx, principal, entry_ex);
		if (ret != HDB_ERR_NOENTRY) goto done;

		/* We return 'no entry' if it does not start with krbtgt/, so move to the common case quickly */
		ret = samba_kdc_fetch_server(context, kdc_db_ctx, mem_ctx, principal, entry_ex);
		if (ret != HDB_ERR_NOENTRY) goto done;
	}
	if (flags & HDB_F_GET_KRBTGT) {
		ret = samba_kdc_fetch_krbtgt(context, kdc_db_ctx, mem_ctx, principal, entry_ex);
		if (ret != HDB_ERR_NOENTRY) goto done;
	}

done:
	talloc_free(mem_ctx);
	return ret;
}

struct samba_kdc_seq {
	int index;
	int count;
	struct ldb_message **msgs;
	struct ldb_dn *realm_dn;
};

static krb5_error_code samba_kdc_seq(krb5_context context,
				     struct samba_kdc_db_context *kdc_db_ctx,
				     hdb_entry_ex *entry)
{
	krb5_error_code ret;
	struct samba_kdc_seq *priv = kdc_db_ctx->seq_ctx;
	TALLOC_CTX *mem_ctx;
	hdb_entry_ex entry_ex;
	memset(&entry_ex, '\0', sizeof(entry_ex));

	if (!priv) {
		return HDB_ERR_NOENTRY;
	}

	mem_ctx = talloc_named(priv, 0, "samba_kdc_seq context");

	if (!mem_ctx) {
		ret = ENOMEM;
		krb5_set_error_message(context, ret, "samba_kdc_seq: talloc_named() failed!");
		return ret;
	}

	if (priv->index < priv->count) {
		ret = samba_kdc_message2entry(context, kdc_db_ctx, mem_ctx,
					NULL, SAMBA_KDC_ENT_TYPE_ANY,
					priv->realm_dn, priv->msgs[priv->index++], entry);
	} else {
		ret = HDB_ERR_NOENTRY;
	}

	if (ret != 0) {
		talloc_free(priv);
		kdc_db_ctx->seq_ctx = NULL;
	} else {
		talloc_free(mem_ctx);
	}

	return ret;
}

krb5_error_code samba_kdc_firstkey(krb5_context context,
				   struct samba_kdc_db_context *kdc_db_ctx,
				   hdb_entry_ex *entry)
{
	struct ldb_context *ldb_ctx = kdc_db_ctx->samdb;
	struct samba_kdc_seq *priv = kdc_db_ctx->seq_ctx;
	char *realm;
	struct ldb_result *res = NULL;
	krb5_error_code ret;
	TALLOC_CTX *mem_ctx;
	int lret;

	if (priv) {
		talloc_free(priv);
		kdc_db_ctx->seq_ctx = NULL;
	}

	priv = (struct samba_kdc_seq *) talloc(kdc_db_ctx, struct samba_kdc_seq);
	if (!priv) {
		ret = ENOMEM;
		krb5_set_error_message(context, ret, "talloc: out of memory");
		return ret;
	}

	priv->index = 0;
	priv->msgs = NULL;
	priv->realm_dn = ldb_get_default_basedn(ldb_ctx);
	priv->count = 0;

	mem_ctx = talloc_named(priv, 0, "samba_kdc_firstkey context");

	if (!mem_ctx) {
		ret = ENOMEM;
		krb5_set_error_message(context, ret, "samba_kdc_firstkey: talloc_named() failed!");
		return ret;
	}

	ret = krb5_get_default_realm(context, &realm);
	if (ret != 0) {
		talloc_free(priv);
		return ret;
	}

	lret = ldb_search(ldb_ctx, priv, &res,
			  priv->realm_dn, LDB_SCOPE_SUBTREE, user_attrs,
			  "(objectClass=user)");

	if (lret != LDB_SUCCESS) {
		talloc_free(priv);
		return HDB_ERR_NOENTRY;
	}

	priv->count = res->count;
	priv->msgs = talloc_steal(priv, res->msgs);
	talloc_free(res);

	kdc_db_ctx->seq_ctx = priv;

	ret = samba_kdc_seq(context, kdc_db_ctx, entry);

	if (ret != 0) {
    		talloc_free(priv);
		kdc_db_ctx->seq_ctx = NULL;
	} else {
		talloc_free(mem_ctx);
	}
	return ret;
}

krb5_error_code samba_kdc_nextkey(krb5_context context,
				  struct samba_kdc_db_context *kdc_db_ctx,
				  hdb_entry_ex *entry)
{
	return samba_kdc_seq(context, kdc_db_ctx, entry);
}

/* Check if a given entry may delegate to this target principal
 *
 * This is currently a very nasty hack - allowing only delegation to itself.
 */
krb5_error_code
samba_kdc_check_constrained_delegation(krb5_context context,
				       struct samba_kdc_db_context *kdc_db_ctx,
					hdb_entry_ex *entry,
					krb5_const_principal target_principal)
{
	krb5_error_code ret;
	krb5_principal enterprise_prinicpal = NULL;
	struct ldb_dn *realm_dn;
	struct ldb_message *msg;
	struct dom_sid *orig_sid;
	struct dom_sid *target_sid;
	struct samba_kdc_entry *p = talloc_get_type(entry->ctx, struct samba_kdc_entry);
	const char *delegation_check_attrs[] = {
		"objectSid", NULL
	};

	TALLOC_CTX *mem_ctx = talloc_named(kdc_db_ctx, 0, "samba_kdc_check_constrained_delegation");

	if (!mem_ctx) {
		ret = ENOMEM;
		krb5_set_error_message(context, ret, "samba_kdc_fetch: talloc_named() failed!");
		return ret;
	}

	if (target_principal->name.name_type == KRB5_NT_ENTERPRISE_PRINCIPAL) {
		/* Need to reparse the enterprise principal to find the real target */
		if (target_principal->name.name_string.len != 1) {
			ret = KRB5_PARSE_MALFORMED;
			krb5_set_error_message(context, ret, "samba_kdc_check_constrained_delegation: request for delegation to enterprise principal with wrong (%d) number of components",
					       target_principal->name.name_string.len);
			talloc_free(mem_ctx);
			return ret;
		}
		ret = krb5_parse_name(context, target_principal->name.name_string.val[0],
				      &enterprise_prinicpal);
		if (ret) {
			talloc_free(mem_ctx);
			return ret;
		}
		target_principal = enterprise_prinicpal;
	}

	ret = samba_kdc_lookup_server(context, kdc_db_ctx, mem_ctx, target_principal,
				       delegation_check_attrs, &realm_dn, &msg);

	krb5_free_principal(context, enterprise_prinicpal);

	if (ret != 0) {
		talloc_free(mem_ctx);
		return ret;
	}

	orig_sid = samdb_result_dom_sid(mem_ctx, p->msg, "objectSid");
	target_sid = samdb_result_dom_sid(mem_ctx, msg, "objectSid");

	/* Allow delegation to the same principal, even if by a different
	 * name.  The easy and safe way to prove this is by SID
	 * comparison */
	if (!(orig_sid && target_sid && dom_sid_equal(orig_sid, target_sid))) {
		talloc_free(mem_ctx);
		return KRB5KDC_ERR_BADOPTION;
	}

	talloc_free(mem_ctx);
	return ret;
}

/* Certificates printed by a the Certificate Authority might have a
 * slightly different form of the user principal name to that in the
 * database.  Allow a mismatch where they both refer to the same
 * SID */

krb5_error_code
samba_kdc_check_pkinit_ms_upn_match(krb5_context context,
				    struct samba_kdc_db_context *kdc_db_ctx,
				     hdb_entry_ex *entry,
				     krb5_const_principal certificate_principal)
{
	krb5_error_code ret;
	struct ldb_dn *realm_dn;
	struct ldb_message *msg;
	struct dom_sid *orig_sid;
	struct dom_sid *target_sid;
	struct samba_kdc_entry *p = talloc_get_type(entry->ctx, struct samba_kdc_entry);
	const char *ms_upn_check_attrs[] = {
		"objectSid", NULL
	};

	TALLOC_CTX *mem_ctx = talloc_named(kdc_db_ctx, 0, "samba_kdc_check_pkinit_ms_upn_match");

	if (!mem_ctx) {
		ret = ENOMEM;
		krb5_set_error_message(context, ret, "samba_kdc_fetch: talloc_named() failed!");
		return ret;
	}

	ret = samba_kdc_lookup_client(context, kdc_db_ctx,
				       mem_ctx, certificate_principal,
				       ms_upn_check_attrs, &realm_dn, &msg);

	if (ret != 0) {
		talloc_free(mem_ctx);
		return ret;
	}

	orig_sid = samdb_result_dom_sid(mem_ctx, p->msg, "objectSid");
	target_sid = samdb_result_dom_sid(mem_ctx, msg, "objectSid");

	/* Consider these to be the same principal, even if by a different
	 * name.  The easy and safe way to prove this is by SID
	 * comparison */
	if (!(orig_sid && target_sid && dom_sid_equal(orig_sid, target_sid))) {
		talloc_free(mem_ctx);
		return KRB5_KDC_ERR_CLIENT_NAME_MISMATCH;
	}

	talloc_free(mem_ctx);
	return ret;
}