summaryrefslogtreecommitdiff
path: root/source4/heimdal/lib/krb5/keytab_file.c
blob: be195d96c26d67104c80d71bb2cf3078ab2a203d (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
/*
 * 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"

RCSID("$Id: keytab_file.c 22532 2008-01-27 11:59:18Z lha $");

#define KRB5_KT_VNO_1 1
#define KRB5_KT_VNO_2 2
#define KRB5_KT_VNO   KRB5_KT_VNO_2

#define KRB5_KT_FL_JAVA 1


/* file operations -------------------------------------------- */

struct fkt_data {
    char *filename;
    int flags;
};

static krb5_error_code
krb5_kt_ret_data(krb5_context context,
		 krb5_storage *sp,
		 krb5_data *data)
{
    int ret;
    int16_t size;
    ret = krb5_ret_int16(sp, &size);
    if(ret)
	return ret;
    data->length = size;
    data->data = malloc(size);
    if (data->data == NULL) {
	krb5_set_error_string (context, "malloc: out of memory");
	return ENOMEM;
    }
    ret = krb5_storage_read(sp, data->data, size);
    if(ret != size)
	return (ret < 0)? errno : KRB5_KT_END;
    return 0;
}

static krb5_error_code
krb5_kt_ret_string(krb5_context context,
		   krb5_storage *sp,
		   heim_general_string *data)
{
    int ret;
    int16_t size;
    ret = krb5_ret_int16(sp, &size);
    if(ret)
	return ret;
    *data = malloc(size + 1);
    if (*data == NULL) {
	krb5_set_error_string (context, "malloc: out of memory");
	return ENOMEM;
    }
    ret = krb5_storage_read(sp, *data, size);
    (*data)[size] = '\0';
    if(ret != size)
	return (ret < 0)? errno : KRB5_KT_END;
    return 0;
}

static krb5_error_code
krb5_kt_store_data(krb5_context context,
		   krb5_storage *sp,
		   krb5_data data)
{
    int ret;
    ret = krb5_store_int16(sp, data.length);
    if(ret < 0)
	return ret;
    ret = krb5_storage_write(sp, data.data, data.length);
    if(ret != data.length){
	if(ret < 0)
	    return errno;
	return KRB5_KT_END;
    }
    return 0;
}

static krb5_error_code
krb5_kt_store_string(krb5_storage *sp,
		     heim_general_string data)
{
    int ret;
    size_t len = strlen(data);
    ret = krb5_store_int16(sp, len);
    if(ret < 0)
	return ret;
    ret = krb5_storage_write(sp, data, len);
    if(ret != len){
	if(ret < 0)
	    return errno;
	return KRB5_KT_END;
    }
    return 0;
}

static krb5_error_code
krb5_kt_ret_keyblock(krb5_context context, krb5_storage *sp, krb5_keyblock *p)
{
    int ret;
    int16_t tmp;

    ret = krb5_ret_int16(sp, &tmp); /* keytype + etype */
    if(ret) return ret;
    p->keytype = tmp;
    ret = krb5_kt_ret_data(context, sp, &p->keyvalue);
    return ret;
}

static krb5_error_code
krb5_kt_store_keyblock(krb5_context context,
		       krb5_storage *sp, 
		       krb5_keyblock *p)
{
    int ret;

    ret = krb5_store_int16(sp, p->keytype); /* keytype + etype */
    if(ret) return ret;
    ret = krb5_kt_store_data(context, sp, p->keyvalue);
    return ret;
}


static krb5_error_code
krb5_kt_ret_principal(krb5_context context,
		      krb5_storage *sp,
		      krb5_principal *princ)
{
    int i;
    int ret;
    krb5_principal p;
    int16_t len;
    
    ALLOC(p, 1);
    if(p == NULL) {
	krb5_set_error_string (context, "malloc: out of memory");
	return ENOMEM;
    }

    ret = krb5_ret_int16(sp, &len);
    if(ret) {
	krb5_set_error_string(context,
			      "Failed decoding length of keytab principal");
	goto out;
    }
    if(krb5_storage_is_flags(sp, KRB5_STORAGE_PRINCIPAL_WRONG_NUM_COMPONENTS))
	len--;
    if (len < 0) {
	krb5_set_error_string(context, 
			      "Keytab principal contains invalid length");
	ret = KRB5_KT_END;
	goto out;
    }
    ret = krb5_kt_ret_string(context, sp, &p->realm);
    if(ret)
	goto out;
    p->name.name_string.val = calloc(len, sizeof(*p->name.name_string.val));
    if(p->name.name_string.val == NULL) {
	krb5_set_error_string (context, "malloc: out of memory");
	ret = ENOMEM;
	goto out;
    }
    p->name.name_string.len = len;
    for(i = 0; i < p->name.name_string.len; i++){
	ret = krb5_kt_ret_string(context, sp, p->name.name_string.val + i);
	if(ret)
	    goto out;
    }
    if (krb5_storage_is_flags(sp, KRB5_STORAGE_PRINCIPAL_NO_NAME_TYPE))
	p->name.name_type = KRB5_NT_UNKNOWN;
    else {
	int32_t tmp32;
	ret = krb5_ret_int32(sp, &tmp32);
	p->name.name_type = tmp32;
	if (ret)
	    goto out;
    }
    *princ = p;
    return 0;
out:
    krb5_free_principal(context, p);
    return ret;
}

static krb5_error_code
krb5_kt_store_principal(krb5_context context,
			krb5_storage *sp,
			krb5_principal p)
{
    int i;
    int ret;
    
    if(krb5_storage_is_flags(sp, KRB5_STORAGE_PRINCIPAL_WRONG_NUM_COMPONENTS))
	ret = krb5_store_int16(sp, p->name.name_string.len + 1);
    else
	ret = krb5_store_int16(sp, p->name.name_string.len);
    if(ret) return ret;
    ret = krb5_kt_store_string(sp, p->realm);
    if(ret) return ret;
    for(i = 0; i < p->name.name_string.len; i++){
	ret = krb5_kt_store_string(sp, p->name.name_string.val[i]);
	if(ret)
	    return ret;
    }
    if(!krb5_storage_is_flags(sp, KRB5_STORAGE_PRINCIPAL_NO_NAME_TYPE)) {
	ret = krb5_store_int32(sp, p->name.name_type);
	if(ret)
	    return ret;
    }

    return 0;
}

static krb5_error_code
fkt_resolve(krb5_context context, const char *name, krb5_keytab id)
{
    struct fkt_data *d;

    d = malloc(sizeof(*d));
    if(d == NULL) {
	krb5_set_error_string (context, "malloc: out of memory");
	return ENOMEM;
    }
    d->filename = strdup(name);
    if(d->filename == NULL) {
	free(d);
	krb5_set_error_string (context, "malloc: out of memory");
	return ENOMEM;
    }
    d->flags = 0;
    id->data = d;
    return 0;
}

static krb5_error_code
fkt_resolve_java14(krb5_context context, const char *name, krb5_keytab id)
{
    krb5_error_code ret;

    ret = fkt_resolve(context, name, id);
    if (ret == 0) {
	struct fkt_data *d = id->data;
	d->flags |= KRB5_KT_FL_JAVA;
    }
    return ret;
}

static krb5_error_code
fkt_close(krb5_context context, krb5_keytab id)
{
    struct fkt_data *d = id->data;
    free(d->filename);
    free(d);
    return 0;
}

static krb5_error_code 
fkt_get_name(krb5_context context, 
	     krb5_keytab id, 
	     char *name, 
	     size_t namesize)
{
    /* This function is XXX */
    struct fkt_data *d = id->data;
    strlcpy(name, d->filename, namesize);
    return 0;
}

static void
storage_set_flags(krb5_context context, krb5_storage *sp, int vno)
{
    int flags = 0;
    switch(vno) {
    case KRB5_KT_VNO_1:
	flags |= KRB5_STORAGE_PRINCIPAL_WRONG_NUM_COMPONENTS;
	flags |= KRB5_STORAGE_PRINCIPAL_NO_NAME_TYPE;
	flags |= KRB5_STORAGE_HOST_BYTEORDER;
	break;
    case KRB5_KT_VNO_2:
	break;
    default:
	krb5_warnx(context, 
		   "storage_set_flags called with bad vno (%d)", vno);
    }
    krb5_storage_set_flags(sp, flags);
}

static krb5_error_code
fkt_start_seq_get_int(krb5_context context, 
		      krb5_keytab id, 
		      int flags,
		      int exclusive,
		      krb5_kt_cursor *c)
{
    int8_t pvno, tag;
    krb5_error_code ret;
    struct fkt_data *d = id->data;
    
    c->fd = open (d->filename, flags);
    if (c->fd < 0) {
	ret = errno;
	krb5_set_error_string(context, "keytab %s open failed: %s", 
			      d->filename, strerror(ret));
	return ret;
    }
    ret = _krb5_xlock(context, c->fd, exclusive, d->filename);
    if (ret) {
	close(c->fd);
	return ret;
    }
    c->sp = krb5_storage_from_fd(c->fd);
    if (c->sp == NULL) {
	_krb5_xunlock(context, c->fd);
	close(c->fd);
	krb5_set_error_string (context, "malloc: out of memory");
	return ENOMEM;
    }
    krb5_storage_set_eof_code(c->sp, KRB5_KT_END);
    ret = krb5_ret_int8(c->sp, &pvno);
    if(ret) {
	krb5_storage_free(c->sp);
	_krb5_xunlock(context, c->fd);
	close(c->fd);
	krb5_clear_error_string(context);
	return ret;
    }
    if(pvno != 5) {
	krb5_storage_free(c->sp);
	_krb5_xunlock(context, c->fd);
	close(c->fd);
	krb5_clear_error_string (context);
	return KRB5_KEYTAB_BADVNO;
    }
    ret = krb5_ret_int8(c->sp, &tag);
    if (ret) {
	krb5_storage_free(c->sp);
	_krb5_xunlock(context, c->fd);
	close(c->fd);
	krb5_clear_error_string(context);
	return ret;
    }
    id->version = tag;
    storage_set_flags(context, c->sp, id->version);
    return 0;
}

static krb5_error_code
fkt_start_seq_get(krb5_context context, 
		  krb5_keytab id, 
		  krb5_kt_cursor *c)
{
    return fkt_start_seq_get_int(context, id, O_RDONLY | O_BINARY, 0, c);
}

static krb5_error_code
fkt_next_entry_int(krb5_context context, 
		   krb5_keytab id, 
		   krb5_keytab_entry *entry, 
		   krb5_kt_cursor *cursor,
		   off_t *start,
		   off_t *end)
{
    int32_t len;
    int ret;
    int8_t tmp8;
    int32_t tmp32;
    off_t pos, curpos;

    pos = krb5_storage_seek(cursor->sp, 0, SEEK_CUR);
loop:
    ret = krb5_ret_int32(cursor->sp, &len);
    if (ret)
	return ret;
    if(len < 0) {
	pos = krb5_storage_seek(cursor->sp, -len, SEEK_CUR);
	goto loop;
    }
    ret = krb5_kt_ret_principal (context, cursor->sp, &entry->principal);
    if (ret)
	goto out;
    ret = krb5_ret_int32(cursor->sp, &tmp32);
    entry->timestamp = tmp32;
    if (ret)
	goto out;
    ret = krb5_ret_int8(cursor->sp, &tmp8);
    if (ret)
	goto out;
    entry->vno = tmp8;
    ret = krb5_kt_ret_keyblock (context, cursor->sp, &entry->keyblock);
    if (ret)
	goto out;
    /* there might be a 32 bit kvno here
     * if it's zero, assume that the 8bit one was right,
     * otherwise trust the new value */
    curpos = krb5_storage_seek(cursor->sp, 0, SEEK_CUR);
    if(len + 4 + pos - curpos >= 4) {
	ret = krb5_ret_int32(cursor->sp, &tmp32);
	if (ret == 0 && tmp32 != 0) {
	    entry->vno = tmp32;
	}
    }
    if(start) *start = pos;
    if(end) *end = pos + 4 + len;
 out:
    krb5_storage_seek(cursor->sp, pos + 4 + len, SEEK_SET);
    return ret;
}

static krb5_error_code
fkt_next_entry(krb5_context context, 
	       krb5_keytab id, 
	       krb5_keytab_entry *entry, 
	       krb5_kt_cursor *cursor)
{
    return fkt_next_entry_int(context, id, entry, cursor, NULL, NULL);
}

static krb5_error_code
fkt_end_seq_get(krb5_context context, 
		krb5_keytab id,
		krb5_kt_cursor *cursor)
{
    krb5_storage_free(cursor->sp);
    _krb5_xunlock(context, cursor->fd);
    close(cursor->fd);
    return 0;
}

static krb5_error_code
fkt_setup_keytab(krb5_context context,
		 krb5_keytab id,
		 krb5_storage *sp)
{
    krb5_error_code ret;
    ret = krb5_store_int8(sp, 5);
    if(ret)
	return ret;
    if(id->version == 0)
	id->version = KRB5_KT_VNO;
    return krb5_store_int8 (sp, id->version);
}
		 
static krb5_error_code
fkt_add_entry(krb5_context context,
	      krb5_keytab id,
	      krb5_keytab_entry *entry)
{
    int ret;
    int fd;
    krb5_storage *sp;
    struct fkt_data *d = id->data;
    krb5_data keytab;
    int32_t len;
    
    fd = open (d->filename, O_RDWR | O_BINARY);
    if (fd < 0) {
	fd = open (d->filename, O_RDWR | O_CREAT | O_EXCL | O_BINARY, 0600);
	if (fd < 0) {
	    ret = errno;
	    krb5_set_error_string(context, "open(%s): %s", d->filename,
				  strerror(ret));
	    return ret;
	}
	ret = _krb5_xlock(context, fd, 1, d->filename);
	if (ret) {
	    close(fd);
	    return ret;
	}
	sp = krb5_storage_from_fd(fd);
	krb5_storage_set_eof_code(sp, KRB5_KT_END);
	ret = fkt_setup_keytab(context, id, sp);
	if(ret) {
	    goto out;
	}
	storage_set_flags(context, sp, id->version);
    } else {
	int8_t pvno, tag;
	ret = _krb5_xlock(context, fd, 1, d->filename);
	if (ret) {
	    close(fd);
	    return ret;
	}
	sp = krb5_storage_from_fd(fd);
	krb5_storage_set_eof_code(sp, KRB5_KT_END);
	ret = krb5_ret_int8(sp, &pvno);
	if(ret) {
	    /* we probably have a zero byte file, so try to set it up
               properly */
	    ret = fkt_setup_keytab(context, id, sp);
	    if(ret) {
		krb5_set_error_string(context, "%s: keytab is corrupted: %s", 
				      d->filename, strerror(ret));
		goto out;
	    }
	    storage_set_flags(context, sp, id->version);
	} else {
	    if(pvno != 5) {
		ret = KRB5_KEYTAB_BADVNO;
		krb5_set_error_string(context, "%s: %s", 
				      d->filename, strerror(ret));
		goto out;
	    }
	    ret = krb5_ret_int8 (sp, &tag);
	    if (ret) {
		krb5_set_error_string(context, "%s: reading tag: %s", 
				      d->filename, strerror(ret));
		goto out;
	    }
	    id->version = tag;
	    storage_set_flags(context, sp, id->version);
	}
    }

    {
	krb5_storage *emem;
	emem = krb5_storage_emem();
	if(emem == NULL) {
	    ret = ENOMEM;
	    krb5_set_error_string (context, "malloc: out of memory");
	    goto out;
	}
	ret = krb5_kt_store_principal(context, emem, entry->principal);
	if(ret) {
	    krb5_storage_free(emem);
	    goto out;
	}
	ret = krb5_store_int32 (emem, entry->timestamp);
	if(ret) {
	    krb5_storage_free(emem);
	    goto out;
	}
	ret = krb5_store_int8 (emem, entry->vno % 256);
	if(ret) {
	    krb5_storage_free(emem);
	    goto out;
	}
	ret = krb5_kt_store_keyblock (context, emem, &entry->keyblock);
	if(ret) {
	    krb5_storage_free(emem);
	    goto out;
	}
	if ((d->flags & KRB5_KT_FL_JAVA) == 0) {
	    ret = krb5_store_int32 (emem, entry->vno);
	    if (ret) {
		krb5_storage_free(emem);
		goto out;
	    }
	}

	ret = krb5_storage_to_data(emem, &keytab);
	krb5_storage_free(emem);
	if(ret)
	    goto out;
    }
    
    while(1) {
	ret = krb5_ret_int32(sp, &len);
	if(ret == KRB5_KT_END) {
	    len = keytab.length;
	    break;
	}
	if(len < 0) {
	    len = -len;
	    if(len >= keytab.length) {
		krb5_storage_seek(sp, -4, SEEK_CUR);
		break;
	    }
	}
	krb5_storage_seek(sp, len, SEEK_CUR);
    }
    ret = krb5_store_int32(sp, len);
    if(krb5_storage_write(sp, keytab.data, keytab.length) < 0)
	ret = errno;
    memset(keytab.data, 0, keytab.length);
    krb5_data_free(&keytab);
  out:
    krb5_storage_free(sp);
    _krb5_xunlock(context, fd);
    close(fd);
    return ret;
}

static krb5_error_code
fkt_remove_entry(krb5_context context,
		 krb5_keytab id,
		 krb5_keytab_entry *entry)
{
    krb5_keytab_entry e;
    krb5_kt_cursor cursor;
    off_t pos_start, pos_end;
    int found = 0;
    krb5_error_code ret;
    
    ret = fkt_start_seq_get_int(context, id, O_RDWR | O_BINARY, 1, &cursor);
    if(ret != 0) 
	goto out; /* return other error here? */
    while(fkt_next_entry_int(context, id, &e, &cursor, 
			     &pos_start, &pos_end) == 0) {
	if(krb5_kt_compare(context, &e, entry->principal, 
			   entry->vno, entry->keyblock.keytype)) {
	    int32_t len;
	    unsigned char buf[128];
	    found = 1;
	    krb5_storage_seek(cursor.sp, pos_start, SEEK_SET);
	    len = pos_end - pos_start - 4;
	    krb5_store_int32(cursor.sp, -len);
	    memset(buf, 0, sizeof(buf));
	    while(len > 0) {
		krb5_storage_write(cursor.sp, buf, min(len, sizeof(buf)));
		len -= min(len, sizeof(buf));
	    }
	}
	krb5_kt_free_entry(context, &e);
    }
    krb5_kt_end_seq_get(context, id, &cursor);
  out:
    if (!found) {
	krb5_clear_error_string (context);
	return KRB5_KT_NOTFOUND;
    }
    return 0;
}

const krb5_kt_ops krb5_fkt_ops = {
    "FILE",
    fkt_resolve,
    fkt_get_name,
    fkt_close,
    NULL, /* get */
    fkt_start_seq_get,
    fkt_next_entry,
    fkt_end_seq_get,
    fkt_add_entry,
    fkt_remove_entry
};

const krb5_kt_ops krb5_wrfkt_ops = {
    "WRFILE",
    fkt_resolve,
    fkt_get_name,
    fkt_close,
    NULL, /* get */
    fkt_start_seq_get,
    fkt_next_entry,
    fkt_end_seq_get,
    fkt_add_entry,
    fkt_remove_entry
};

const krb5_kt_ops krb5_javakt_ops = {
    "JAVA14",
    fkt_resolve_java14,
    fkt_get_name,
    fkt_close,
    NULL, /* get */
    fkt_start_seq_get,
    fkt_next_entry,
    fkt_end_seq_get,
    fkt_add_entry,
    fkt_remove_entry
};