summaryrefslogtreecommitdiff
path: root/source4/heimdal/lib/krb5/keytab.c
blob: fcc74e847ea976e78572cd8cfae8b2da63aa18a9 (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
/*
 * Copyright (c) 1997 - 2005 Kungliga Tekniska Högskolan
 * (Royal Institute of Technology, Stockholm, Sweden).
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include "krb5_locl.h"

/**
 * @page krb5_keytab_intro The keytab handing functions
 * @section section_krb5_keytab Kerberos Keytabs
 *
 * See the library functions here: @ref krb5_keytab
 *
 * Keytabs are long term key storage for servers, their equvalment of
 * password files.
 *
 * Normally the only function that useful for server are to specify
 * what keytab to use to other core functions like krb5_rd_req()
 * krb5_kt_resolve(), and krb5_kt_close().
 *
 * @subsection krb5_keytab_names Keytab names
 *
 * A keytab name is on the form type:residual. The residual part is
 * specific to each keytab-type.
 * 
 * When a keytab-name is resolved, the type is matched with an internal
 * list of keytab types. If there is no matching keytab type,
 * the default keytab is used. The current default type is FILE.
 *
 * The default value can be changed in the configuration file
 * /etc/krb5.conf by setting the variable
 * [defaults]default_keytab_name.
 *
 * The keytab types that are implemented in Heimdal are:
 * - file 
 *   store the keytab in a file, the type's name is FILE .  The
 *   residual part is a filename. For compatibility with other
 *   Kerberos implemtation WRFILE and JAVA14 is also accepted.  WRFILE
 *   has the same format as FILE. JAVA14 have a format that is
 *   compatible with older versions of MIT kerberos and SUN's Java
 *   based installation.  They store a truncted kvno, so when the knvo
 *   excess 255, they are truncted in this format.
 *
 * - keytab
 *   store the keytab in a AFS keyfile (usually /usr/afs/etc/KeyFile ),
 *   the type's name is AFSKEYFILE. The residual part is a filename.
 *
 * - krb4
 *   the keytab is a Kerberos 4 srvtab that is on-the-fly converted to
 *   a keytab. The type's name is krb4 The residual part is a
 *   filename.
 *
 * - memory
 *   The keytab is stored in a memory segment. This allows sensitive
 *   and/or temporary data not to be stored on disk. The type's name
 *   is MEMORY. Each MEMORY keytab is referenced counted by and
 *   opened by the residual name, so two handles can point to the
 *   same memory area.  When the last user closes the entry, it
 *   disappears.
 *
 *
 * @subsection krb5_keytab_example Keytab example
 *
 *  This is a minimalistic version of ktutil.
 *
 * @code
int
main (int argc, char **argv)
{
    krb5_context context;
    krb5_keytab keytab;
    krb5_kt_cursor cursor;
    krb5_keytab_entry entry;
    krb5_error_code ret;
    char *principal;

    if (krb5_init_context (&context) != 0)
	errx(1, "krb5_context");

    ret = krb5_kt_default (context, &keytab);
    if (ret)
	krb5_err(context, 1, ret, "krb5_kt_default");

    ret = krb5_kt_start_seq_get(context, keytab, &cursor);
    if (ret)
	krb5_err(context, 1, ret, "krb5_kt_start_seq_get");
    while((ret = krb5_kt_next_entry(context, keytab, &entry, &cursor)) == 0){
	krb5_unparse_name_short(context, entry.principal, &principal);
	printf("principal: %s\n", principal);
	free(principal);
	krb5_kt_free_entry(context, &entry);
    }
    ret = krb5_kt_end_seq_get(context, keytab, &cursor);
    if (ret)
	krb5_err(context, 1, ret, "krb5_kt_end_seq_get");
    ret = krb5_kt_close(context, keytab);
    if (ret)
	krb5_err(context, 1, ret, "krb5_kt_close");
    krb5_free_context(context);
    return 0;
}
 * @endcode
 *
 */


/**
 * Register a new keytab backend.
 *
 * @param context a Keberos context.
 * @param ops a backend to register.
 *
 * @return Return an error code or 0, see krb5_get_error_message().
 *
 * @ingroup krb5_keytab
 */

krb5_error_code KRB5_LIB_FUNCTION
krb5_kt_register(krb5_context context,
		 const krb5_kt_ops *ops)
{
    struct krb5_keytab_data *tmp;

    if (strlen(ops->prefix) > KRB5_KT_PREFIX_MAX_LEN - 1) {
	krb5_set_error_message(context, KRB5_KT_BADNAME,
			       N_("can't register cache type, prefix too long", ""));
	return KRB5_KT_BADNAME;
    }

    tmp = realloc(context->kt_types,
		  (context->num_kt_types + 1) * sizeof(*context->kt_types));
    if(tmp == NULL) {
	krb5_set_error_message(context, ENOMEM,
			       N_("malloc: out of memory", ""));
	return ENOMEM;
    }
    memcpy(&tmp[context->num_kt_types], ops,
	   sizeof(tmp[context->num_kt_types]));
    context->kt_types = tmp;
    context->num_kt_types++;
    return 0;
}

/**
 * Resolve the keytab name (of the form `type:residual') in `name'
 * into a keytab in `id'.
 *
 * @param context a Keberos context.
 * @param name name to resolve
 * @param id resulting keytab, free with krb5_kt_close().
 *
 * @return Return an error code or 0, see krb5_get_error_message().
 *
 * @ingroup krb5_keytab
 */


krb5_error_code KRB5_LIB_FUNCTION
krb5_kt_resolve(krb5_context context,
		const char *name,
		krb5_keytab *id)
{
    krb5_keytab k;
    int i;
    const char *type, *residual;
    size_t type_len;
    krb5_error_code ret;

    residual = strchr(name, ':');
    if(residual == NULL) {
	type = "FILE";
	type_len = strlen(type);
	residual = name;
    } else {
	type = name;
	type_len = residual - name;
	residual++;
    }

    for(i = 0; i < context->num_kt_types; i++) {
	if(strncasecmp(type, context->kt_types[i].prefix, type_len) == 0)
	    break;
    }
    if(i == context->num_kt_types) {
	krb5_set_error_message(context, KRB5_KT_UNKNOWN_TYPE,
			       N_("unknown keytab type %.*s", "type"),
			       (int)type_len, type);
	return KRB5_KT_UNKNOWN_TYPE;
    }

    k = malloc (sizeof(*k));
    if (k == NULL) {
	krb5_set_error_message(context, ENOMEM, N_("malloc: out of memory", ""));
	return ENOMEM;
    }
    memcpy(k, &context->kt_types[i], sizeof(*k));
    k->data = NULL;
    ret = (*k->resolve)(context, residual, k);
    if(ret) {
	free(k);
	k = NULL;
    }
    *id = k;
    return ret;
}

/**
 * copy the name of the default keytab into `name'.
 *
 * @param context a Keberos context.
 * @param name buffer where the name will be written
 * @param namesize length of name
 *
 * @return Return an error code or 0, see krb5_get_error_message().
 *
 * @ingroup krb5_keytab
 */

krb5_error_code KRB5_LIB_FUNCTION
krb5_kt_default_name(krb5_context context, char *name, size_t namesize)
{
    if (strlcpy (name, context->default_keytab, namesize) >= namesize) {
	krb5_clear_error_message (context);
	return KRB5_CONFIG_NOTENUFSPACE;
    }
    return 0;
}

/**
 * Copy the name of the default modify keytab into `name'.
 *
 * @param context a Keberos context.
 * @param name buffer where the name will be written
 * @param namesize length of name
 *
 * @return Return an error code or 0, see krb5_get_error_message().
 *
 * @ingroup krb5_keytab
 */

krb5_error_code KRB5_LIB_FUNCTION
krb5_kt_default_modify_name(krb5_context context, char *name, size_t namesize)
{
    const char *kt = NULL;
    if(context->default_keytab_modify == NULL) {
	if(strncasecmp(context->default_keytab, "ANY:", 4) != 0)
	    kt = context->default_keytab;
	else {
	    size_t len = strcspn(context->default_keytab + 4, ",");
	    if(len >= namesize) {
		krb5_clear_error_message(context);
		return KRB5_CONFIG_NOTENUFSPACE;
	    }
	    strlcpy(name, context->default_keytab + 4, namesize);
	    name[len] = '\0';
	    return 0;
	}
    } else
	kt = context->default_keytab_modify;
    if (strlcpy (name, kt, namesize) >= namesize) {
	krb5_clear_error_message (context);
	return KRB5_CONFIG_NOTENUFSPACE;
    }
    return 0;
}

/**
 * Set `id' to the default keytab.
 *
 * @param context a Keberos context.
 * @param id the new default keytab.
 *
 * @return Return an error code or 0, see krb5_get_error_message().
 *
 * @ingroup krb5_keytab
 */

krb5_error_code KRB5_LIB_FUNCTION
krb5_kt_default(krb5_context context, krb5_keytab *id)
{
    return krb5_kt_resolve (context, context->default_keytab, id);
}

/**
 * Read the key identified by `(principal, vno, enctype)' from the
 * keytab in `keyprocarg' (the default if == NULL) into `*key'.
 *
 * @param context a Keberos context.
 * @param keyprocarg
 * @param principal
 * @param vno
 * @param enctype
 * @param key
 *
 * @return Return an error code or 0, see krb5_get_error_message().
 *
 * @ingroup krb5_keytab
 */

krb5_error_code KRB5_LIB_FUNCTION
krb5_kt_read_service_key(krb5_context context,
			 krb5_pointer keyprocarg,
			 krb5_principal principal,
			 krb5_kvno vno,
			 krb5_enctype enctype,
			 krb5_keyblock **key)
{
    krb5_keytab keytab;
    krb5_keytab_entry entry;
    krb5_error_code ret;

    if (keyprocarg)
	ret = krb5_kt_resolve (context, keyprocarg, &keytab);
    else
	ret = krb5_kt_default (context, &keytab);

    if (ret)
	return ret;

    ret = krb5_kt_get_entry (context, keytab, principal, vno, enctype, &entry);
    krb5_kt_close (context, keytab);
    if (ret)
	return ret;
    ret = krb5_copy_keyblock (context, &entry.keyblock, key);
    krb5_kt_free_entry(context, &entry);
    return ret;
}

/**
 * Return the type of the `keytab' in the string `prefix of length
 * `prefixsize'.
 *
 * @param context a Keberos context.
 * @param keytab the keytab to get the prefix for
 * @param prefix prefix buffer
 * @param prefixsize length of prefix buffer
 *
 * @return Return an error code or 0, see krb5_get_error_message().
 *
 * @ingroup krb5_keytab
 */

krb5_error_code KRB5_LIB_FUNCTION
krb5_kt_get_type(krb5_context context,
		 krb5_keytab keytab,
		 char *prefix,
		 size_t prefixsize)
{
    strlcpy(prefix, keytab->prefix, prefixsize);
    return 0;
}

/**
 * Retrieve the name of the keytab `keytab' into `name', `namesize'
 *
 * @param context a Keberos context.
 * @param keytab the keytab to get the name for.
 * @param name name buffer.
 * @param namesize size of name buffer.
 *
 * @return Return an error code or 0, see krb5_get_error_message().
 *
 * @ingroup krb5_keytab
 */

krb5_error_code KRB5_LIB_FUNCTION
krb5_kt_get_name(krb5_context context,
		 krb5_keytab keytab,
		 char *name,
		 size_t namesize)
{
    return (*keytab->get_name)(context, keytab, name, namesize);
}

/**
 * Retrieve the full name of the keytab `keytab' and store the name in
 * `str'.
 *
 * @param context a Keberos context.
 * @param keytab keytab to get name for.
 * @param str the name of the keytab name, usee krb5_xfree() to free
 *        the string.  On error, *str is set to NULL.
 *
 * @return Return an error code or 0, see krb5_get_error_message().
 *
 * @ingroup krb5_keytab
 */

krb5_error_code KRB5_LIB_FUNCTION
krb5_kt_get_full_name(krb5_context context,
		      krb5_keytab keytab,
		      char **str)
{
    char type[KRB5_KT_PREFIX_MAX_LEN];
    char name[MAXPATHLEN];
    krb5_error_code ret;
	
    *str = NULL;

    ret = krb5_kt_get_type(context, keytab, type, sizeof(type));
    if (ret)
	return ret;

    ret = krb5_kt_get_name(context, keytab, name, sizeof(name));
    if (ret)
	return ret;

    if (asprintf(str, "%s:%s", type, name) == -1) {
	krb5_set_error_message(context, ENOMEM, N_("malloc: out of memory", ""));
	*str = NULL;
	return ENOMEM;
    }

    return 0;
}

/**
 * Finish using the keytab in `id'.  All resources will be released,
 * even on errors.
 *
 * @param context a Keberos context.
 * @param id keytab to close.
 *
 * @return Return an error code or 0, see krb5_get_error_message().
 *
 * @ingroup krb5_keytab
 */

krb5_error_code KRB5_LIB_FUNCTION
krb5_kt_close(krb5_context context,
	      krb5_keytab id)
{
    krb5_error_code ret;

    ret = (*id->close)(context, id);
    memset(id, 0, sizeof(*id));
    free(id);
    return ret;
}

/**
 * Destroy (remove) the keytab in `id'.  All resources will be released,
 * even on errors, does the equvalment of krb5_kt_close() on the resources.
 *
 * @param context a Keberos context.
 * @param id keytab to destroy.
 *
 * @return Return an error code or 0, see krb5_get_error_message().
 *
 * @ingroup krb5_keytab
 */

krb5_error_code KRB5_LIB_FUNCTION
krb5_kt_destroy(krb5_context context,
		krb5_keytab id)
{
    krb5_error_code ret;

    ret = (*id->destroy)(context, id);
    krb5_kt_close(context, id);
    return ret;
}

/*
 * Match any aliases in keytab `entry' with `principal'.
 */

static krb5_boolean
compare_aliseses(krb5_context context,
		 krb5_keytab_entry *entry,
		 krb5_const_principal principal)
{
    unsigned int i;
    if (entry->aliases == NULL)
	return FALSE;
    for (i = 0; i < entry->aliases->len; i++)
	if (krb5_principal_compare(context, &entry->aliases->val[i], principal))
	    return TRUE;
    return FALSE;
}

/**
 * Compare `entry' against `principal, vno, enctype'.
 * Any of `principal, vno, enctype' might be 0 which acts as a wildcard.
 * Return TRUE if they compare the same, FALSE otherwise.
 *
 * @param context a Keberos context.
 * @param entry an entry to match with.
 * @param principal principal to match, NULL matches all principals.
 * @param vno key version to match, 0 matches all key version numbers.
 * @param enctype encryption type to match, 0 matches all encryption types.
 *
 * @return Return TRUE or match, FALSE if not matched.
 *
 * @ingroup krb5_keytab
 */

krb5_boolean KRB5_LIB_FUNCTION
krb5_kt_compare(krb5_context context,
		krb5_keytab_entry *entry,
		krb5_const_principal principal,
		krb5_kvno vno,
		krb5_enctype enctype)
{
    if(principal != NULL &&
       !(krb5_principal_compare(context, entry->principal, principal) ||
	 compare_aliseses(context, entry, principal)))
	return FALSE;
    if(vno && vno != entry->vno)
	return FALSE;
    if(enctype && enctype != entry->keyblock.keytype)
	return FALSE;
    return TRUE;
}

krb5_error_code
_krb5_kt_principal_not_found(krb5_context context,
			     krb5_error_code ret,
			     krb5_keytab id,
			     krb5_const_principal principal,
			     krb5_enctype enctype,
			     int kvno)
{
    char princ[256], kvno_str[25], *kt_name;
    char *enctype_str = NULL;
    
    krb5_unparse_name_fixed (context, principal, princ, sizeof(princ));
    krb5_kt_get_full_name (context, id, &kt_name);
    krb5_enctype_to_string(context, enctype, &enctype_str);
    
    if (kvno)
	snprintf(kvno_str, sizeof(kvno_str), "(kvno %d)", kvno);
    else
	kvno_str[0] = '\0';
    
    krb5_set_error_message (context, ret,
			    N_("Failed to find %s%s in keytab %s (%s)",
			       "principal, kvno, keytab file, enctype"),
			    princ,
			    kvno_str,
			    kt_name ? kt_name : "unknown keytab",
			    enctype_str ? enctype_str : "unknown enctype");
    free(kt_name);
    free(enctype_str);
    return ret;
}


/**
 * Retrieve the keytab entry for `principal, kvno, enctype' into `entry'
 * from the keytab `id'. Matching is done like krb5_kt_compare().
 *
 * @param context a Keberos context.
 * @param id a keytab.
 * @param principal principal to match, NULL matches all principals.
 * @param kvno key version to match, 0 matches all key version numbers.
 * @param enctype encryption type to match, 0 matches all encryption types.
 * @param entry the returned entry, free with krb5_kt_free_entry().
 *
 * @return Return an error code or 0, see krb5_get_error_message().
 *
 * @ingroup krb5_keytab
 */

krb5_error_code KRB5_LIB_FUNCTION
krb5_kt_get_entry(krb5_context context,
		  krb5_keytab id,
		  krb5_const_principal principal,
		  krb5_kvno kvno,
		  krb5_enctype enctype,
		  krb5_keytab_entry *entry)
{
    krb5_keytab_entry tmp;
    krb5_error_code ret;
    krb5_kt_cursor cursor;

    if(id->get)
	return (*id->get)(context, id, principal, kvno, enctype, entry);

    ret = krb5_kt_start_seq_get (context, id, &cursor);
    if (ret) {
	/* This is needed for krb5_verify_init_creds, but keep error
	 * string from previous error for the human. */
	context->error_code = KRB5_KT_NOTFOUND;
	return KRB5_KT_NOTFOUND;
    }

    entry->vno = 0;
    while (krb5_kt_next_entry(context, id, &tmp, &cursor) == 0) {
	if (krb5_kt_compare(context, &tmp, principal, 0, enctype)) {
	    /* the file keytab might only store the lower 8 bits of
	       the kvno, so only compare those bits */
	    if (kvno == tmp.vno
		|| (tmp.vno < 256 && kvno % 256 == tmp.vno)) {
		krb5_kt_copy_entry_contents (context, &tmp, entry);
		krb5_kt_free_entry (context, &tmp);
		krb5_kt_end_seq_get(context, id, &cursor);
		return 0;
	    } else if (kvno == 0 && tmp.vno > entry->vno) {
		if (entry->vno)
		    krb5_kt_free_entry (context, entry);
		krb5_kt_copy_entry_contents (context, &tmp, entry);
	    }
	}
	krb5_kt_free_entry(context, &tmp);
    }
    krb5_kt_end_seq_get (context, id, &cursor);
    if (entry->vno == 0)
	return _krb5_kt_principal_not_found(context, KRB5_KT_NOTFOUND,
					    id, principal, enctype, kvno);
    return 0;
}

/**
 * Copy the contents of `in' into `out'.
 *
 * @param context a Keberos context.
 * @param in the keytab entry to copy.
 * @param out the copy of the keytab entry, free with krb5_kt_free_entry().
 *
 * @return Return an error code or 0, see krb5_get_error_message().
 *
 * @ingroup krb5_keytab
 */

krb5_error_code KRB5_LIB_FUNCTION
krb5_kt_copy_entry_contents(krb5_context context,
			    const krb5_keytab_entry *in,
			    krb5_keytab_entry *out)
{
    krb5_error_code ret;

    memset(out, 0, sizeof(*out));
    out->vno = in->vno;

    ret = krb5_copy_principal (context, in->principal, &out->principal);
    if (ret)
	goto fail;
    ret = krb5_copy_keyblock_contents (context,
				       &in->keyblock,
				       &out->keyblock);
    if (ret)
	goto fail;
    out->timestamp = in->timestamp;
    return 0;
fail:
    krb5_kt_free_entry (context, out);
    return ret;
}

/**
 * Free the contents of `entry'.
 *
 * @param context a Keberos context.
 * @param entry the entry to free
 *
 * @return Return an error code or 0, see krb5_get_error_message().
 *
 * @ingroup krb5_keytab
 */

krb5_error_code KRB5_LIB_FUNCTION
krb5_kt_free_entry(krb5_context context,
		   krb5_keytab_entry *entry)
{
    krb5_free_principal (context, entry->principal);
    krb5_free_keyblock_contents (context, &entry->keyblock);
    memset(entry, 0, sizeof(*entry));
    return 0;
}

/**
 * Set `cursor' to point at the beginning of `id'.
 *
 * @param context a Keberos context.
 * @param id a keytab.
 * @param cursor a newly allocated cursor, free with krb5_kt_end_seq_get().
 *
 * @return Return an error code or 0, see krb5_get_error_message().
 *
 * @ingroup krb5_keytab
 */

krb5_error_code KRB5_LIB_FUNCTION
krb5_kt_start_seq_get(krb5_context context,
		      krb5_keytab id,
		      krb5_kt_cursor *cursor)
{
    if(id->start_seq_get == NULL) {
	krb5_set_error_message(context, HEIM_ERR_OPNOTSUPP,
			       N_("start_seq_get is not supported "
				  "in the %s keytab type", ""),
			       id->prefix);
	return HEIM_ERR_OPNOTSUPP;
    }
    return (*id->start_seq_get)(context, id, cursor);
}

/**
 * Get the next entry from keytab, advance the cursor.  On last entry
 * the function will return KRB5_KT_END.
 *
 * @param context a Keberos context.
 * @param id a keytab.
 * @param entry the returned entry, free with krb5_kt_free_entry().
 * @param cursor the cursor of the iteration.
 *
 * @return Return an error code or 0, see krb5_get_error_message().
 *
 * @ingroup krb5_keytab
 */

krb5_error_code KRB5_LIB_FUNCTION
krb5_kt_next_entry(krb5_context context,
		   krb5_keytab id,
		   krb5_keytab_entry *entry,
		   krb5_kt_cursor *cursor)
{
    if(id->next_entry == NULL) {
	krb5_set_error_message(context, HEIM_ERR_OPNOTSUPP,
			       N_("next_entry is not supported in the %s "
				  " keytab", ""),
			       id->prefix);
	return HEIM_ERR_OPNOTSUPP;
    }
    return (*id->next_entry)(context, id, entry, cursor);
}

/**
 * Release all resources associated with `cursor'.
 *
 * @param context a Keberos context.
 * @param id a keytab.
 * @param cursor the cursor to free.
 *
 * @return Return an error code or 0, see krb5_get_error_message().
 *
 * @ingroup krb5_keytab
 */

krb5_error_code KRB5_LIB_FUNCTION
krb5_kt_end_seq_get(krb5_context context,
		    krb5_keytab id,
		    krb5_kt_cursor *cursor)
{
    if(id->end_seq_get == NULL) {
	krb5_set_error_message(context, HEIM_ERR_OPNOTSUPP,
			       "end_seq_get is not supported in the %s "
			       " keytab", id->prefix);
	return HEIM_ERR_OPNOTSUPP;
    }
    return (*id->end_seq_get)(context, id, cursor);
}

/**
 * Add the entry in `entry' to the keytab `id'.
 *
 * @param context a Keberos context.
 * @param id a keytab.
 * @param entry the entry to add
 *
 * @return Return an error code or 0, see krb5_get_error_message().
 *
 * @ingroup krb5_keytab
 */

krb5_error_code KRB5_LIB_FUNCTION
krb5_kt_add_entry(krb5_context context,
		  krb5_keytab id,
		  krb5_keytab_entry *entry)
{
    if(id->add == NULL) {
	krb5_set_error_message(context, KRB5_KT_NOWRITE,
			       N_("Add is not supported in the %s keytab", ""),
			       id->prefix);
	return KRB5_KT_NOWRITE;
    }
    entry->timestamp = time(NULL);
    return (*id->add)(context, id,entry);
}

/**
 * Remove an entry from the keytab, matching is done using
 * krb5_kt_compare().

 * @param context a Keberos context.
 * @param id a keytab.
 * @param entry the entry to remove
 *
 * @return Return an error code or 0, see krb5_get_error_message().
 *
 * @ingroup krb5_keytab
 */

krb5_error_code KRB5_LIB_FUNCTION
krb5_kt_remove_entry(krb5_context context,
		     krb5_keytab id,
		     krb5_keytab_entry *entry)
{
    if(id->remove == NULL) {
	krb5_set_error_message(context, KRB5_KT_NOWRITE,
			       N_("Remove is not supported in the %s keytab", ""),
			       id->prefix);
	return KRB5_KT_NOWRITE;
    }
    return (*id->remove)(context, id, entry);
}