summaryrefslogtreecommitdiff
path: root/source3/libads/kerberos.c
blob: 4fc23956bdef17689263021d2715bedff73bbd62 (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
/* 
   Unix SMB/CIFS implementation.
   kerberos utility library
   Copyright (C) Andrew Tridgell 2001
   Copyright (C) Remus Koos 2001
   Copyright (C) Nalin Dahyabhai <nalin@redhat.com> 2004.
   Copyright (C) Jeremy Allison 2004.
   Copyright (C) Gerald Carter 2006.

   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"

#ifdef HAVE_KRB5

#define LIBADS_CCACHE_NAME "MEMORY:libads"

/*
  we use a prompter to avoid a crash bug in the kerberos libs when 
  dealing with empty passwords
  this prompter is just a string copy ...
*/
static krb5_error_code 
kerb_prompter(krb5_context ctx, void *data,
	       const char *name,
	       const char *banner,
	       int num_prompts,
	       krb5_prompt prompts[])
{
	if (num_prompts == 0) return 0;

	memset(prompts[0].reply->data, '\0', prompts[0].reply->length);
	if (prompts[0].reply->length > 0) {
		if (data) {
			strncpy(prompts[0].reply->data, (const char *)data,
				prompts[0].reply->length-1);
			prompts[0].reply->length = strlen(prompts[0].reply->data);
		} else {
			prompts[0].reply->length = 0;
		}
	}
	return 0;
}

static bool smb_krb5_err_io_nstatus(TALLOC_CTX *mem_ctx, 
				    DATA_BLOB *edata_blob, 
				    KRB5_EDATA_NTSTATUS *edata)
{
	bool ret = False;
	prs_struct ps;

	if (!mem_ctx || !edata_blob || !edata) 
		return False;

	if (!prs_init(&ps, edata_blob->length, mem_ctx, UNMARSHALL))
		return False;

	if (!prs_copy_data_in(&ps, (char *)edata_blob->data, edata_blob->length))
		goto out;

	prs_set_offset(&ps, 0);

	if (!prs_ntstatus("ntstatus", &ps, 1, &edata->ntstatus))
		goto out;

	if (!prs_uint32("unknown1", &ps, 1, &edata->unknown1))
		goto out;

	if (!prs_uint32("unknown2", &ps, 1, &edata->unknown2)) /* only seen 00000001 here */
		goto out;

	ret = True;
 out:
	prs_mem_free(&ps);

	return ret;
}

 static bool smb_krb5_get_ntstatus_from_krb5_error(krb5_error *error,
						   NTSTATUS *nt_status)
{
	DATA_BLOB edata;
	DATA_BLOB unwrapped_edata;
	TALLOC_CTX *mem_ctx;
	KRB5_EDATA_NTSTATUS parsed_edata;

#ifdef HAVE_E_DATA_POINTER_IN_KRB5_ERROR
	edata = data_blob(error->e_data->data, error->e_data->length);
#else
	edata = data_blob(error->e_data.data, error->e_data.length);
#endif /* HAVE_E_DATA_POINTER_IN_KRB5_ERROR */

#ifdef DEVELOPER
	dump_data(10, edata.data, edata.length);
#endif /* DEVELOPER */

	mem_ctx = talloc_init("smb_krb5_get_ntstatus_from_krb5_error");
	if (mem_ctx == NULL) {
		data_blob_free(&edata);
		return False;
	}

	if (!unwrap_edata_ntstatus(mem_ctx, &edata, &unwrapped_edata)) {
		data_blob_free(&edata);
		TALLOC_FREE(mem_ctx);
		return False;
	}

	data_blob_free(&edata);

	if (!smb_krb5_err_io_nstatus(mem_ctx, &unwrapped_edata, &parsed_edata)) {
		data_blob_free(&unwrapped_edata);
		TALLOC_FREE(mem_ctx);
		return False;
	}

	data_blob_free(&unwrapped_edata);

	if (nt_status) {
		*nt_status = parsed_edata.ntstatus;
	}

	TALLOC_FREE(mem_ctx);

	return True;
}

 static bool smb_krb5_get_ntstatus_from_krb5_error_init_creds_opt(krb5_context ctx, 
 								  krb5_get_init_creds_opt *opt, 
								  NTSTATUS *nt_status)
{
	bool ret = False;
	krb5_error *error = NULL;

#ifdef HAVE_KRB5_GET_INIT_CREDS_OPT_GET_ERROR
	ret = krb5_get_init_creds_opt_get_error(ctx, opt, &error);
	if (ret) {
		DEBUG(1,("krb5_get_init_creds_opt_get_error gave: %s\n", 
			error_message(ret)));
		return False;
	}
#endif /* HAVE_KRB5_GET_INIT_CREDS_OPT_GET_ERROR */

	if (!error) {
		DEBUG(1,("no krb5_error\n"));
		return False;
	}

#ifdef HAVE_E_DATA_POINTER_IN_KRB5_ERROR
	if (!error->e_data) {
#else
	if (error->e_data.data == NULL) {
#endif /* HAVE_E_DATA_POINTER_IN_KRB5_ERROR */
		DEBUG(1,("no edata in krb5_error\n")); 
		krb5_free_error(ctx, error);
		return False;
	}

	ret = smb_krb5_get_ntstatus_from_krb5_error(error, nt_status);

	krb5_free_error(ctx, error);

	return ret;
}

/*
  simulate a kinit, putting the tgt in the given cache location. If cache_name == NULL
  place in default cache location.
  remus@snapserver.com
*/
int kerberos_kinit_password_ext(const char *principal,
				const char *password,
				int time_offset,
				time_t *expire_time,
				time_t *renew_till_time,
				const char *cache_name,
				bool request_pac,
				bool add_netbios_addr,
				time_t renewable_time,
				NTSTATUS *ntstatus)
{
	krb5_context ctx = NULL;
	krb5_error_code code = 0;
	krb5_ccache cc = NULL;
	krb5_principal me = NULL;
	krb5_creds my_creds;
	krb5_get_init_creds_opt *opt = NULL;
	smb_krb5_addresses *addr = NULL;

	ZERO_STRUCT(my_creds);

	initialize_krb5_error_table();
	if ((code = krb5_init_context(&ctx)))
		goto out;

	if (time_offset != 0) {
		krb5_set_real_time(ctx, time(NULL) + time_offset, 0);
	}

	DEBUG(10,("kerberos_kinit_password: using [%s] as ccache and config [%s]\n",
			cache_name ? cache_name: krb5_cc_default_name(ctx),
			getenv("KRB5_CONFIG")));

	if ((code = krb5_cc_resolve(ctx, cache_name ? cache_name : krb5_cc_default_name(ctx), &cc))) {
		goto out;
	}
	
	if ((code = smb_krb5_parse_name(ctx, principal, &me))) {
		goto out;
	}

	if ((code = smb_krb5_get_init_creds_opt_alloc(ctx, &opt))) {
		goto out;
	}

	krb5_get_init_creds_opt_set_renew_life(opt, renewable_time);
	krb5_get_init_creds_opt_set_forwardable(opt, True);
#if 0
	/* insane testing */
	krb5_get_init_creds_opt_set_tkt_life(opt, 60);
#endif

#ifdef HAVE_KRB5_GET_INIT_CREDS_OPT_SET_PAC_REQUEST
	if (request_pac) {
		if ((code = krb5_get_init_creds_opt_set_pac_request(ctx, opt, (krb5_boolean)request_pac))) {
			goto out;
		}
	}
#endif
	if (add_netbios_addr) {
		if ((code = smb_krb5_gen_netbios_krb5_address(&addr))) {
			goto out;
		}
		krb5_get_init_creds_opt_set_address_list(opt, addr->addrs);
	}

	if ((code = krb5_get_init_creds_password(ctx, &my_creds, me, CONST_DISCARD(char *,password), 
						 kerb_prompter, CONST_DISCARD(char *,password),
						 0, NULL, opt))) {
		goto out;
	}

	if ((code = krb5_cc_initialize(ctx, cc, me))) {
		goto out;
	}
	
	if ((code = krb5_cc_store_cred(ctx, cc, &my_creds))) {
		goto out;
	}

	if (expire_time) {
		*expire_time = (time_t) my_creds.times.endtime;
	}

	if (renew_till_time) {
		*renew_till_time = (time_t) my_creds.times.renew_till;
	}
 out:
	if (ntstatus) {

		NTSTATUS status;

		/* fast path */
		if (code == 0) {
			*ntstatus = NT_STATUS_OK;
			goto cleanup;
		}

		/* try to get ntstatus code out of krb5_error when we have it
		 * inside the krb5_get_init_creds_opt - gd */

		if (opt && smb_krb5_get_ntstatus_from_krb5_error_init_creds_opt(ctx, opt, &status)) {
			*ntstatus = status;
			goto cleanup;
		}

		/* fall back to self-made-mapping */
		*ntstatus = krb5_to_nt_status(code);
	}

 cleanup:
	krb5_free_cred_contents(ctx, &my_creds);
	if (me) {
		krb5_free_principal(ctx, me);
	}
	if (addr) {
		smb_krb5_free_addresses(ctx, addr);
	}
 	if (opt) {
		smb_krb5_get_init_creds_opt_free(ctx, opt);
	}
	if (cc) {
		krb5_cc_close(ctx, cc);
	}
	if (ctx) {
		krb5_free_context(ctx);
	}
	return code;
}



/* run kinit to setup our ccache */
int ads_kinit_password(ADS_STRUCT *ads)
{
	char *s;
	int ret;
	const char *account_name;
	fstring acct_name;

	if ( IS_DC ) {
		/* this will end up getting a ticket for DOMAIN@RUSTED.REA.LM */
		account_name = lp_workgroup();
	} else {
		/* always use the sAMAccountName for security = domain */
		/* global_myname()$@REA.LM */
		if ( lp_security() == SEC_DOMAIN ) {
			fstr_sprintf( acct_name, "%s$", global_myname() );
			account_name = acct_name;
		}
		else 
			/* This looks like host/global_myname()@REA.LM */
			account_name = ads->auth.user_name;
	}

	if (asprintf(&s, "%s@%s", account_name, ads->auth.realm) == -1) {
		return KRB5_CC_NOMEM;
	}

	if (!ads->auth.password) {
		SAFE_FREE(s);
		return KRB5_LIBOS_CANTREADPWD;
	}
	
	ret = kerberos_kinit_password_ext(s, ads->auth.password, ads->auth.time_offset,
			&ads->auth.tgt_expire, NULL, NULL, False, False, ads->auth.renewable, 
			NULL);

	if (ret) {
		DEBUG(0,("kerberos_kinit_password %s failed: %s\n", 
			 s, error_message(ret)));
	}
	SAFE_FREE(s);
	return ret;
}

int ads_kdestroy(const char *cc_name)
{
	krb5_error_code code;
	krb5_context ctx = NULL;
	krb5_ccache cc = NULL;

	initialize_krb5_error_table();
	if ((code = krb5_init_context (&ctx))) {
		DEBUG(3, ("ads_kdestroy: kdb5_init_context failed: %s\n", 
			error_message(code)));
		return code;
	}
  
	if (!cc_name) {
		if ((code = krb5_cc_default(ctx, &cc))) {
			krb5_free_context(ctx);
			return code;
		}
	} else {
		if ((code = krb5_cc_resolve(ctx, cc_name, &cc))) {
			DEBUG(3, ("ads_kdestroy: krb5_cc_resolve failed: %s\n",
				  error_message(code)));
			krb5_free_context(ctx);
			return code;
		}
	}

	if ((code = krb5_cc_destroy (ctx, cc))) {
		DEBUG(3, ("ads_kdestroy: krb5_cc_destroy failed: %s\n", 
			error_message(code)));
	}

	krb5_free_context (ctx);
	return code;
}

/************************************************************************
 Routine to fetch the salting principal for a service.  Active
 Directory may use a non-obvious principal name to generate the salt
 when it determines the key to use for encrypting tickets for a service,
 and hopefully we detected that when we joined the domain.
 ************************************************************************/

static char *kerberos_secrets_fetch_salting_principal(const char *service, int enctype)
{
	char *key = NULL;
	char *ret = NULL;

	asprintf(&key, "%s/%s/enctype=%d", SECRETS_SALTING_PRINCIPAL, service, enctype);
	if (!key) {
		return NULL;
	}
	ret = (char *)secrets_fetch(key, NULL);
	SAFE_FREE(key);
	return ret;
}

/************************************************************************
 Return the standard DES salt key
************************************************************************/

char* kerberos_standard_des_salt( void )
{
	fstring salt;

	fstr_sprintf( salt, "host/%s.%s@", global_myname(), lp_realm() );
	strlower_m( salt );
	fstrcat( salt, lp_realm() );

	return SMB_STRDUP( salt );
}

/************************************************************************
************************************************************************/

static char* des_salt_key( void )
{
	char *key;

	asprintf(&key, "%s/DES/%s", SECRETS_SALTING_PRINCIPAL, lp_realm());

	return key;
}

/************************************************************************
************************************************************************/

bool kerberos_secrets_store_des_salt( const char* salt )
{
	char* key;
	bool ret;

	if ( (key = des_salt_key()) == NULL ) {
		DEBUG(0,("kerberos_secrets_store_des_salt: failed to generate key!\n"));
		return False;
	}

	if ( !salt ) {
		DEBUG(8,("kerberos_secrets_store_des_salt: deleting salt\n"));
		secrets_delete( key );
		return True;
	}

	DEBUG(3,("kerberos_secrets_store_des_salt: Storing salt \"%s\"\n", salt));

	ret = secrets_store( key, salt, strlen(salt)+1 );

	SAFE_FREE( key );

	return ret;
}

/************************************************************************
************************************************************************/

char* kerberos_secrets_fetch_des_salt( void )
{
	char *salt, *key;

	if ( (key = des_salt_key()) == NULL ) {
		DEBUG(0,("kerberos_secrets_fetch_des_salt: failed to generate key!\n"));
		return False;
	}

	salt = (char*)secrets_fetch( key, NULL );

	SAFE_FREE( key );

	return salt;
}

/************************************************************************
 Routine to get the default realm from the kerberos credentials cache.
 Caller must free if the return value is not NULL.
************************************************************************/

char *kerberos_get_default_realm_from_ccache( void )
{
	char *realm = NULL;
	krb5_context ctx = NULL;
	krb5_ccache cc = NULL;
	krb5_principal princ = NULL;

	initialize_krb5_error_table();
	if (krb5_init_context(&ctx)) {
		return NULL;
	}

	DEBUG(5,("kerberos_get_default_realm_from_ccache: "
		"Trying to read krb5 cache: %s\n",
		krb5_cc_default_name(ctx)));
	if (krb5_cc_default(ctx, &cc)) {
		DEBUG(0,("kerberos_get_default_realm_from_ccache: "
			"failed to read default cache\n"));
		goto out;
	}
	if (krb5_cc_get_principal(ctx, cc, &princ)) {
		DEBUG(0,("kerberos_get_default_realm_from_ccache: "
			"failed to get default principal\n"));
		goto out;
	}

#if defined(HAVE_KRB5_PRINCIPAL_GET_REALM)
	realm = SMB_STRDUP(krb5_principal_get_realm(ctx, princ));
#elif defined(HAVE_KRB5_PRINC_REALM)
	{
		krb5_data *realm_data = krb5_princ_realm(ctx, princ);
		realm = SMB_STRNDUP(realm_data->data, realm_data->length);
	}
#endif

  out:

	if (princ) {
		krb5_free_principal(ctx, princ);
	}
	if (cc) {
		krb5_cc_close(ctx, cc);
	}
	if (ctx) {
		krb5_free_context(ctx);
	}

	return realm;
}


/************************************************************************
 Routine to get the salting principal for this service.  This is 
 maintained for backwards compatibilty with releases prior to 3.0.24.
 Since we store the salting principal string only at join, we may have 
 to look for the older tdb keys.  Caller must free if return is not null.
 ************************************************************************/

krb5_principal kerberos_fetch_salt_princ_for_host_princ(krb5_context context,
							krb5_principal host_princ,
							int enctype)
{
	char *unparsed_name = NULL, *salt_princ_s = NULL;
	krb5_principal ret_princ = NULL;
	
	/* lookup new key first */

	if ( (salt_princ_s = kerberos_secrets_fetch_des_salt()) == NULL ) {
	
		/* look under the old key.  If this fails, just use the standard key */

		if (smb_krb5_unparse_name(context, host_princ, &unparsed_name) != 0) {
			return (krb5_principal)NULL;
		}
		if ((salt_princ_s = kerberos_secrets_fetch_salting_principal(unparsed_name, enctype)) == NULL) {
			/* fall back to host/machine.realm@REALM */
			salt_princ_s = kerberos_standard_des_salt();
		}
	}

	if (smb_krb5_parse_name(context, salt_princ_s, &ret_princ) != 0) {
		ret_princ = NULL;
	}
	
	SAFE_FREE(unparsed_name);
	SAFE_FREE(salt_princ_s);
	
	return ret_princ;
}

/************************************************************************
 Routine to set the salting principal for this service.  Active
 Directory may use a non-obvious principal name to generate the salt
 when it determines the key to use for encrypting tickets for a service,
 and hopefully we detected that when we joined the domain.
 Setting principal to NULL deletes this entry.
 ************************************************************************/

bool kerberos_secrets_store_salting_principal(const char *service,
					      int enctype,
					      const char *principal)
{
	char *key = NULL;
	bool ret = False;
	krb5_context context = NULL;
	krb5_principal princ = NULL;
	char *princ_s = NULL;
	char *unparsed_name = NULL;

	krb5_init_context(&context);
	if (!context) {
		return False;
	}
	if (strchr_m(service, '@')) {
		asprintf(&princ_s, "%s", service);
	} else {
		asprintf(&princ_s, "%s@%s", service, lp_realm());
	}

	if (smb_krb5_parse_name(context, princ_s, &princ) != 0) {
		goto out;
		
	}
	if (smb_krb5_unparse_name(context, princ, &unparsed_name) != 0) {
		goto out;
	}

	asprintf(&key, "%s/%s/enctype=%d", SECRETS_SALTING_PRINCIPAL, unparsed_name, enctype);
	if (!key)  {
		goto out;
	}

	if ((principal != NULL) && (strlen(principal) > 0)) {
		ret = secrets_store(key, principal, strlen(principal) + 1);
	} else {
		ret = secrets_delete(key);
	}

 out:

	SAFE_FREE(key);
	SAFE_FREE(princ_s);
	SAFE_FREE(unparsed_name);

	if (context) {
		krb5_free_context(context);
	}

	return ret;
}


/************************************************************************
************************************************************************/

int kerberos_kinit_password(const char *principal,
			    const char *password,
			    int time_offset,
			    const char *cache_name)
{
	return kerberos_kinit_password_ext(principal, 
					   password, 
					   time_offset, 
					   0, 
					   0,
					   cache_name,
					   False,
					   False,
					   0,
					   NULL);
}

/************************************************************************
 Create a string list of available kdc's, possibly searching by sitename.
 Does DNS queries.
************************************************************************/

static char *get_kdc_ip_string(char *mem_ctx,
		const char *realm,
		const char *sitename,
		struct sockaddr_storage *pss)
{
	int i;
	struct ip_service *ip_srv_site = NULL;
	struct ip_service *ip_srv_nonsite;
	int count_site = 0;
	int count_nonsite;
	char *kdc_str = talloc_asprintf(mem_ctx, "\tkdc = %s\n",
					print_canonical_sockaddr(mem_ctx,
							pss));

	if (kdc_str == NULL) {
		return NULL;
	}

	/* Get the KDC's only in this site. */

	if (sitename) {

		get_kdc_list(realm, sitename, &ip_srv_site, &count_site);

		for (i = 0; i < count_site; i++) {
			if (addr_equal(&ip_srv_site[i].ss, pss)) {
				continue;
			}
			/* Append to the string - inefficient
			 * but not done often. */
			kdc_str = talloc_asprintf(mem_ctx, "%s\tkdc = %s\n",
				kdc_str,
				print_canonical_sockaddr(mem_ctx,
							&ip_srv_site[i].ss));
			if (!kdc_str) {
				SAFE_FREE(ip_srv_site);
				return NULL;
			}
		}
	}

	/* Get all KDC's. */

	get_kdc_list(realm, NULL, &ip_srv_nonsite, &count_nonsite);

	for (i = 0; i < count_nonsite; i++) {
		int j;

		if (addr_equal(&ip_srv_nonsite[i].ss, pss)) {
			continue;
		}

		/* Ensure this isn't an IP already seen (YUK! this is n*n....) */
		for (j = 0; j < count_site; j++) {
			if (addr_equal(&ip_srv_nonsite[i].ss,
						&ip_srv_site[j].ss)) {
				break;
			}
			/* As the lists are sorted we can break early if nonsite > site. */
			if (ip_service_compare(&ip_srv_nonsite[i], &ip_srv_site[j]) > 0) {
				break;
			}
		}
		if (j != i) {
			continue;
		}

		/* Append to the string - inefficient but not done often. */
		kdc_str = talloc_asprintf(mem_ctx, "%s\tkdc = %s\n",
				kdc_str,
				print_canonical_sockaddr(mem_ctx,
						&ip_srv_nonsite[i].ss));
		if (!kdc_str) {
			SAFE_FREE(ip_srv_site);
			SAFE_FREE(ip_srv_nonsite);
			return NULL;
		}
	}


	SAFE_FREE(ip_srv_site);
	SAFE_FREE(ip_srv_nonsite);

	DEBUG(10,("get_kdc_ip_string: Returning %s\n",
		kdc_str ));

	return kdc_str;
}

/************************************************************************
 Create  a specific krb5.conf file in the private directory pointing
 at a specific kdc for a realm. Keyed off domain name. Sets
 KRB5_CONFIG environment variable to point to this file. Must be
 run as root or will fail (which is a good thing :-).
************************************************************************/

bool create_local_private_krb5_conf_for_domain(const char *realm,
						const char *domain,
						const char *sitename,
						struct sockaddr_storage *pss)
{
	char *dname = talloc_asprintf(NULL, "%s/smb_krb5", lp_lockdir());
	char *tmpname = NULL;
	char *fname = NULL;
	char *file_contents = NULL;
	char *kdc_ip_string = NULL;
	size_t flen = 0;
	ssize_t ret;
	int fd;
	char *realm_upper = NULL;

	if (!dname) {
		return False;
	}
	if ((mkdir(dname, 0755)==-1) && (errno != EEXIST)) {
		DEBUG(0,("create_local_private_krb5_conf_for_domain: "
			"failed to create directory %s. Error was %s\n",
			dname, strerror(errno) ));
		TALLOC_FREE(dname);
		return False;
	}

	tmpname = talloc_asprintf(dname, "%s/smb_tmp_krb5.XXXXXX", lp_lockdir());
	if (!tmpname) {
		TALLOC_FREE(dname);
		return False;
	}

	fname = talloc_asprintf(dname, "%s/krb5.conf.%s", dname, domain);
	if (!fname) {
		TALLOC_FREE(dname);
		return False;
	}

	DEBUG(10,("create_local_private_krb5_conf_for_domain: fname = %s, realm = %s, domain = %s\n",
		fname, realm, domain ));

	realm_upper = talloc_strdup(fname, realm);
	strupper_m(realm_upper);

	kdc_ip_string = get_kdc_ip_string(dname, realm, sitename, pss);
	if (!kdc_ip_string) {
		TALLOC_FREE(dname);
		return False;
	}

	file_contents = talloc_asprintf(fname, "[libdefaults]\n\tdefault_realm = %s\n\n"
				"[realms]\n\t%s = {\n"
				"\t%s\t}\n",
				realm_upper, realm_upper, kdc_ip_string);

	if (!file_contents) {
		TALLOC_FREE(dname);
		return False;
	}

	flen = strlen(file_contents);

	fd = smb_mkstemp(tmpname);
	if (fd == -1) {
		DEBUG(0,("create_local_private_krb5_conf_for_domain: smb_mkstemp failed,"
			" for file %s. Errno %s\n",
			tmpname, strerror(errno) ));
	}

	if (fchmod(fd, 0644)==-1) {
		DEBUG(0,("create_local_private_krb5_conf_for_domain: fchmod failed for %s."
			" Errno %s\n",
			tmpname, strerror(errno) ));
		unlink(tmpname);
		close(fd);
		TALLOC_FREE(dname);
		return False;
	}

	ret = write(fd, file_contents, flen);
	if (flen != ret) {
		DEBUG(0,("create_local_private_krb5_conf_for_domain: write failed,"
			" returned %d (should be %u). Errno %s\n",
			(int)ret, (unsigned int)flen, strerror(errno) ));
		unlink(tmpname);
		close(fd);
		TALLOC_FREE(dname);
		return False;
	}
	if (close(fd)==-1) {
		DEBUG(0,("create_local_private_krb5_conf_for_domain: close failed."
			" Errno %s\n", strerror(errno) ));
		unlink(tmpname);
		TALLOC_FREE(dname);
		return False;
	}

	if (rename(tmpname, fname) == -1) {
		DEBUG(0,("create_local_private_krb5_conf_for_domain: rename "
			"of %s to %s failed. Errno %s\n",
			tmpname, fname, strerror(errno) ));
		unlink(tmpname);
		TALLOC_FREE(dname);
		return False;
	}

	DEBUG(5,("create_local_private_krb5_conf_for_domain: wrote "
		"file %s with realm %s KDC = %s\n",
		fname, realm_upper, print_canonical_sockaddr(dname, pss) ));

	/* Set the environment variable to this file. */
	setenv("KRB5_CONFIG", fname, 1);

#if defined(OVERWRITE_SYSTEM_KRB5_CONF)

#define SYSTEM_KRB5_CONF_PATH "/etc/krb5.conf"
	/* Insanity, sheer insanity..... */

	if (strequal(realm, lp_realm())) {
		char linkpath[PATH_MAX+1];
		int lret;

		lret = readlink(SYSTEM_KRB5_CONF_PATH, linkpath, sizeof(linkpath)-1);
		if (lret != -1) {
			linkpath[lret] = '\0';
		}

		if (lret != -1 || strcmp(linkpath, fname) == 0) {
			/* Symlink already exists. */
			TALLOC_FREE(dname);
			return True;
		}

		/* Try and replace with a symlink. */
		if (symlink(fname, SYSTEM_KRB5_CONF_PATH) == -1) {
			const char *newpath = SYSTEM_KRB5_CONF_PATH ## ".saved";
			if (errno != EEXIST) {
				DEBUG(0,("create_local_private_krb5_conf_for_domain: symlink "
					"of %s to %s failed. Errno %s\n",
					fname, SYSTEM_KRB5_CONF_PATH, strerror(errno) ));
				TALLOC_FREE(dname);
				return True; /* Not a fatal error. */
			}

			/* Yes, this is a race conditon... too bad. */
			if (rename(SYSTEM_KRB5_CONF_PATH, newpath) == -1) {
				DEBUG(0,("create_local_private_krb5_conf_for_domain: rename "
					"of %s to %s failed. Errno %s\n",
					SYSTEM_KRB5_CONF_PATH, newpath,
					strerror(errno) ));
				TALLOC_FREE(dname);
				return True; /* Not a fatal error. */
			}

			if (symlink(fname, SYSTEM_KRB5_CONF_PATH) == -1) {
				DEBUG(0,("create_local_private_krb5_conf_for_domain: "
					"forced symlink of %s to /etc/krb5.conf failed. Errno %s\n",
					fname, strerror(errno) ));
				TALLOC_FREE(dname);
				return True; /* Not a fatal error. */
			}
		}
	}
#endif

	TALLOC_FREE(dname);

	return True;
}
#endif