summaryrefslogtreecommitdiff
path: root/lib/x509/crl.c
blob: 82deb5e60a88d1afba757bbf40098aaf05d1e72d (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
/*
 * Copyright (C) 2003-2016 Free Software Foundation, Inc.
 * Copyright (C) 2015-2016 Red Hat, Inc.
 *
 * Author: Nikos Mavrogiannopoulos
 *
 * This file is part of GnuTLS.
 *
 * The GnuTLS is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>
 *
 */

#include "gnutls_int.h"
#include <libtasn1.h>

#include <datum.h>
#include <global.h>
#include "errors.h"
#include <common.h>
#include <x509_b64.h>
#include <x509_int.h>
#include <x509.h>

static int crl_reinit(gnutls_x509_crl_t crl)
{
int result;

	if (crl->crl)
		asn1_delete_structure(&crl->crl);

	result = asn1_create_element(_gnutls_get_pkix(),
				 "PKIX1.CertificateList",
				 &crl->crl);
	if (result != ASN1_SUCCESS) {
		gnutls_assert();
		return _gnutls_asn2err(result);
	}
	crl->rcache = NULL;
	crl->rcache_idx = 0;
	crl->raw_issuer_dn.size = 0;

	return 0;
}

/**
 * gnutls_x509_crl_init:
 * @crl: A pointer to the type to be initialized
 *
 * This function will initialize a CRL structure. CRL stands for
 * Certificate Revocation List. A revocation list usually contains
 * lists of certificate serial numbers that have been revoked by an
 * Authority. The revocation lists are always signed with the
 * authority's private key.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 **/
int gnutls_x509_crl_init(gnutls_x509_crl_t * crl)
{
	FAIL_IF_LIB_ERROR;

	*crl = gnutls_calloc(1, sizeof(gnutls_x509_crl_int));

	if (*crl) {
		int result = crl_reinit(*crl);
		if (result < 0) {
			gnutls_assert();
			gnutls_free(*crl);
			return result;
		}
		return 0;	/* success */
	}
	return GNUTLS_E_MEMORY_ERROR;
}

/**
 * gnutls_x509_crl_deinit:
 * @crl: The data to be deinitialized
 *
 * This function will deinitialize a CRL structure.
 **/
void gnutls_x509_crl_deinit(gnutls_x509_crl_t crl)
{
	if (!crl)
		return;

	if (crl->crl)
		asn1_delete_structure(&crl->crl);
	gnutls_free(crl->der.data);

	gnutls_free(crl);
}

/**
 * gnutls_x509_crl_import:
 * @crl: The data to store the parsed CRL.
 * @data: The DER or PEM encoded CRL.
 * @format: One of DER or PEM
 *
 * This function will convert the given DER or PEM encoded CRL
 * to the native #gnutls_x509_crl_t format. The output will be stored in 'crl'.
 *
 * If the CRL is PEM encoded it should have a header of "X509 CRL".
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 **/
int
gnutls_x509_crl_import(gnutls_x509_crl_t crl,
		       const gnutls_datum_t * data,
		       gnutls_x509_crt_fmt_t format)
{
	int result = 0;

	if (crl == NULL) {
		gnutls_assert();
		return GNUTLS_E_INVALID_REQUEST;
	}

	_gnutls_free_datum(&crl->der);

	/* If the CRL is in PEM format then decode it
	 */
	if (format == GNUTLS_X509_FMT_PEM) {
		result =
		    _gnutls_fbase64_decode(PEM_CRL, data->data, data->size,
					   &crl->der);

		if (result < 0) {
			gnutls_assert();
			return result;
		}
	} else {
		result = _gnutls_set_datum(&crl->der, data->data, data->size);
		if (result < 0) {
			gnutls_assert();
			return result;
		}
	}

	if (crl->expanded) {
		result = crl_reinit(crl);
		if (result < 0) {
			gnutls_assert();
			goto cleanup;
		}
	}
	crl->expanded = 1;

	result =
	    _asn1_strict_der_decode(&crl->crl, crl->der.data, crl->der.size, NULL);
	if (result != ASN1_SUCCESS) {
		result = _gnutls_asn2err(result);
		gnutls_assert();
		goto cleanup;
	}

	result = _gnutls_x509_get_raw_field2(crl->crl, &crl->der,
					  "tbsCertList.issuer.rdnSequence",
					  &crl->raw_issuer_dn);
	if (result < 0) {
		gnutls_assert();
		goto cleanup;
	}

	return 0;

      cleanup:
	_gnutls_free_datum(&crl->der);
	return result;
}


/**
 * gnutls_x509_crl_get_issuer_dn:
 * @crl: should contain a gnutls_x509_crl_t type
 * @buf: a pointer to a structure to hold the peer's name (may be null)
 * @sizeof_buf: initially holds the size of @buf
 *
 * This function will copy the name of the CRL issuer in the provided
 * buffer. The name will be in the form "C=xxxx,O=yyyy,CN=zzzz" as
 * described in RFC4514. The output string will be ASCII or UTF-8
 * encoded, depending on the certificate data.
 *
 * If buf is %NULL then only the size will be filled.
 *
 * This function does not output a fully RFC4514 compliant string, if
 * that is required see gnutls_x509_crl_get_issuer_dn3().
 *
 * Returns: %GNUTLS_E_SHORT_MEMORY_BUFFER if the provided buffer is
 * not long enough, and in that case the sizeof_buf will be updated
 * with the required size, and 0 on success.
 *
 **/
int
gnutls_x509_crl_get_issuer_dn(gnutls_x509_crl_t crl, char *buf,
			      size_t * sizeof_buf)
{
	if (crl == NULL) {
		gnutls_assert();
		return GNUTLS_E_INVALID_REQUEST;
	}

	return _gnutls_x509_parse_dn(crl->crl,
				     "tbsCertList.issuer.rdnSequence",
				     buf, sizeof_buf, GNUTLS_X509_DN_FLAG_COMPAT);
}

/**
 * gnutls_x509_crl_get_issuer_dn_by_oid:
 * @crl: should contain a gnutls_x509_crl_t type
 * @oid: holds an Object Identified in null terminated string
 * @indx: In case multiple same OIDs exist in the RDN, this specifies which to send. Use (0) to get the first one.
 * @raw_flag: If non-zero returns the raw DER data of the DN part.
 * @buf: a pointer to a structure to hold the peer's name (may be null)
 * @sizeof_buf: initially holds the size of @buf
 *
 * This function will extract the part of the name of the CRL issuer
 * specified by the given OID. The output will be encoded as described
 * in RFC4514. The output string will be ASCII or UTF-8 encoded,
 * depending on the certificate data.
 *
 * Some helper macros with popular OIDs can be found in gnutls/x509.h
 * If raw flag is (0), this function will only return known OIDs as
 * text. Other OIDs will be DER encoded, as described in RFC4514 -- in
 * hex format with a '#' prefix.  You can check about known OIDs
 * using gnutls_x509_dn_oid_known().
 *
 * If buf is null then only the size will be filled.
 *
 * Returns: %GNUTLS_E_SHORT_MEMORY_BUFFER if the provided buffer is
 * not long enough, and in that case the sizeof_buf will be updated
 * with the required size, and 0 on success.
 **/
int
gnutls_x509_crl_get_issuer_dn_by_oid(gnutls_x509_crl_t crl,
				     const char *oid, unsigned indx,
				     unsigned int raw_flag, void *buf,
				     size_t * sizeof_buf)
{
	gnutls_datum_t td;
	int ret;

	if (crl == NULL) {
		gnutls_assert();
		return GNUTLS_E_INVALID_REQUEST;
	}

	ret = _gnutls_x509_parse_dn_oid(crl->crl,
					"tbsCertList.issuer.rdnSequence",
					oid, indx, raw_flag, &td);
	if (ret < 0)
		return gnutls_assert_val(ret);

	return _gnutls_strdatum_to_buf(&td, buf, sizeof_buf);
}


/**
 * gnutls_x509_crl_get_dn_oid:
 * @crl: should contain a gnutls_x509_crl_t type
 * @indx: Specifies which DN OID to send. Use (0) to get the first one.
 * @oid: a pointer to store the OID (may be null)
 * @sizeof_oid: initially holds the size of 'oid'
 *
 * This function will extract the requested OID of the name of the CRL
 * issuer, specified by the given index.
 *
 * If oid is null then only the size will be filled.
 *
 * Returns: %GNUTLS_E_SHORT_MEMORY_BUFFER if the provided buffer is
 * not long enough, and in that case the sizeof_oid will be updated
 * with the required size.  On success 0 is returned.
 **/
int
gnutls_x509_crl_get_dn_oid(gnutls_x509_crl_t crl,
			   unsigned indx, void *oid, size_t * sizeof_oid)
{
	if (crl == NULL) {
		gnutls_assert();
		return GNUTLS_E_INVALID_REQUEST;
	}

	return _gnutls_x509_get_dn_oid(crl->crl,
				       "tbsCertList.issuer.rdnSequence",
				       indx, oid, sizeof_oid);
}

/**
 * gnutls_x509_crl_get_issuer_dn2:
 * @crl: should contain a #gnutls_x509_crl_t type
 * @dn: a pointer to a structure to hold the name
 *
 * This function will allocate buffer and copy the name of the CRL issuer.
 * The name will be in the form "C=xxxx,O=yyyy,CN=zzzz" as
 * described in RFC4514. The output string will be ASCII or UTF-8
 * encoded, depending on the certificate data.
 *
 * This function does not output a fully RFC4514 compliant string, if
 * that is required see gnutls_x509_crl_get_issuer_dn3().
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 3.1.10
 **/
int
gnutls_x509_crl_get_issuer_dn2(gnutls_x509_crl_t crl, gnutls_datum_t * dn)
{
	if (crl == NULL) {
		gnutls_assert();
		return GNUTLS_E_INVALID_REQUEST;
	}

	return _gnutls_x509_get_dn(crl->crl,
				   "tbsCertList.issuer.rdnSequence",
				   dn, GNUTLS_X509_DN_FLAG_COMPAT);
}

/**
 * gnutls_x509_crl_get_issuer_dn3:
 * @crl: should contain a #gnutls_x509_crl_t type
 * @dn: a pointer to a structure to hold the name
 * @flags: zero or %GNUTLS_X509_DN_FLAG_COMPAT
 *
 * This function will allocate buffer and copy the name of the CRL issuer.
 * The name will be in the form "C=xxxx,O=yyyy,CN=zzzz" as
 * described in RFC4514. The output string will be ASCII or UTF-8
 * encoded, depending on the certificate data.
 *
 * When the flag %GNUTLS_X509_DN_FLAG_COMPAT is specified, the output
 * format will match the format output by previous to 3.5.6 versions of GnuTLS
 * which was not not fully RFC4514-compliant.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 3.5.7
 **/
int
gnutls_x509_crl_get_issuer_dn3(gnutls_x509_crl_t crl, gnutls_datum_t * dn, unsigned flags)
{
	if (crl == NULL) {
		gnutls_assert();
		return GNUTLS_E_INVALID_REQUEST;
	}

	return _gnutls_x509_get_dn(crl->crl,
				   "tbsCertList.issuer.rdnSequence",
				   dn, flags);
}

/**
 * gnutls_x509_crl_get_signature_algorithm:
 * @crl: should contain a #gnutls_x509_crl_t type
 *
 * This function will return a value of the #gnutls_sign_algorithm_t
 * enumeration that is the signature algorithm.
 *
 * Since 3.6.0 this function never returns a negative error code.
 * Error cases and unknown/unsupported signature algorithms are
 * mapped to %GNUTLS_SIGN_UNKNOWN.
 *
 * Returns: a #gnutls_sign_algorithm_t value
 **/
int gnutls_x509_crl_get_signature_algorithm(gnutls_x509_crl_t crl)
{
	return map_errs_to_zero(_gnutls_x509_get_signature_algorithm(crl->crl,
						    "signatureAlgorithm"));
}

/**
 * gnutls_x509_crl_get_signature_oid:
 * @crl: should contain a #gnutls_x509_crl_t type
 * @oid: a pointer to a buffer to hold the OID (may be null)
 * @oid_size: initially holds the size of @oid
 *
 * This function will return the OID of the signature algorithm
 * that has been used to sign this CRL. This is function
 * is useful in the case gnutls_x509_crl_get_signature_algorithm()
 * returned %GNUTLS_SIGN_UNKNOWN.
 *
 * Returns: zero or a negative error code on error.
 *
 * Since: 3.5.0
 **/
int gnutls_x509_crl_get_signature_oid(gnutls_x509_crl_t crl, char *oid, size_t *oid_size)
{
	char str[MAX_OID_SIZE];
	int len, result, ret;
	gnutls_datum_t out;

	len = sizeof(str);
	result = asn1_read_value(crl->crl, "signatureAlgorithm.algorithm", str, &len);
	if (result != ASN1_SUCCESS) {
		gnutls_assert();
		return _gnutls_asn2err(result);
	}

	out.data = (void*)str;
	out.size = len;

	ret = _gnutls_copy_string(&out, (void*)oid, oid_size);
	if (ret < 0) {
		gnutls_assert();
		return ret;
	}

	return 0;
}

/**
 * gnutls_x509_crl_get_signature:
 * @crl: should contain a gnutls_x509_crl_t type
 * @sig: a pointer where the signature part will be copied (may be null).
 * @sizeof_sig: initially holds the size of @sig
 *
 * This function will extract the signature field of a CRL.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value. 
 **/
int
gnutls_x509_crl_get_signature(gnutls_x509_crl_t crl,
			      char *sig, size_t * sizeof_sig)
{
	int result;
	unsigned int bits;
	int len;

	if (crl == NULL) {
		gnutls_assert();
		return GNUTLS_E_INVALID_REQUEST;
	}

	len = 0;
	result = asn1_read_value(crl->crl, "signature", NULL, &len);

	if (result != ASN1_MEM_ERROR) {
		gnutls_assert();
		return _gnutls_asn2err(result);
	}

	bits = len;
	if (bits % 8 != 0) {
		gnutls_assert();
		return GNUTLS_E_CERTIFICATE_ERROR;
	}

	len = bits / 8;

	if (*sizeof_sig < (unsigned) len) {
		*sizeof_sig = bits / 8;
		return GNUTLS_E_SHORT_MEMORY_BUFFER;
	}

	result = asn1_read_value(crl->crl, "signature", sig, &len);
	if (result != ASN1_SUCCESS) {
		gnutls_assert();
		return _gnutls_asn2err(result);
	}

	return 0;
}

/**
 * gnutls_x509_crl_get_version:
 * @crl: should contain a #gnutls_x509_crl_t type
 *
 * This function will return the version of the specified CRL.
 *
 * Returns: The version number, or a negative error code on error.
 **/
int gnutls_x509_crl_get_version(gnutls_x509_crl_t crl)
{
	uint8_t version[8];
	int len, result;

	if (crl == NULL) {
		gnutls_assert();
		return GNUTLS_E_INVALID_REQUEST;
	}

	len = sizeof(version);
	if ((result =
	     asn1_read_value(crl->crl, "tbsCertList.version", version,
			     &len)) != ASN1_SUCCESS) {
		gnutls_assert();
		return _gnutls_asn2err(result);
	}

	return (int) version[0] + 1;
}

/**
 * gnutls_x509_crl_get_this_update:
 * @crl: should contain a #gnutls_x509_crl_t type
 *
 * This function will return the time this CRL was issued.
 *
 * Returns: when the CRL was issued, or (time_t)-1 on error.
 **/
time_t gnutls_x509_crl_get_this_update(gnutls_x509_crl_t crl)
{
	if (crl == NULL) {
		gnutls_assert();
		return (time_t) - 1;
	}

	return _gnutls_x509_get_time(crl->crl, "tbsCertList.thisUpdate",
				     0);
}

/**
 * gnutls_x509_crl_get_next_update:
 * @crl: should contain a #gnutls_x509_crl_t type
 *
 * This function will return the time the next CRL will be issued.
 * This field is optional in a CRL so it might be normal to get an
 * error instead.
 *
 * Returns: when the next CRL will be issued, or (time_t)-1 on error.
 **/
time_t gnutls_x509_crl_get_next_update(gnutls_x509_crl_t crl)
{
	if (crl == NULL) {
		gnutls_assert();
		return (time_t) - 1;
	}

	return _gnutls_x509_get_time(crl->crl, "tbsCertList.nextUpdate",
				     0);
}

/**
 * gnutls_x509_crl_get_crt_count:
 * @crl: should contain a #gnutls_x509_crl_t type
 *
 * This function will return the number of revoked certificates in the
 * given CRL.
 *
 * Returns: number of certificates, a negative error code on failure.
 **/
int gnutls_x509_crl_get_crt_count(gnutls_x509_crl_t crl)
{

	int count, result;

	if (crl == NULL) {
		gnutls_assert();
		return GNUTLS_E_INVALID_REQUEST;
	}

	result =
	    asn1_number_of_elements(crl->crl,
				    "tbsCertList.revokedCertificates",
				    &count);

	if (result != ASN1_SUCCESS) {
		gnutls_assert();
		return 0;	/* no certificates */
	}

	return count;
}

/**
 * gnutls_x509_crl_get_crt_serial:
 * @crl: should contain a #gnutls_x509_crl_t type
 * @indx: the index of the certificate to extract (starting from 0)
 * @serial: where the serial number will be copied
 * @serial_size: initially holds the size of serial
 * @t: if non null, will hold the time this certificate was revoked
 *
 * This function will retrieve the serial number of the specified, by
 * the index, revoked certificate.
 *
 * Note that this function will have performance issues in large sequences
 * of revoked certificates. In that case use gnutls_x509_crl_iter_crt_serial().
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 **/
int
gnutls_x509_crl_get_crt_serial(gnutls_x509_crl_t crl, unsigned indx,
			       unsigned char *serial,
			       size_t * serial_size, time_t * t)
{

	int result, _serial_size;
	char serial_name[MAX_NAME_SIZE];
	char date_name[MAX_NAME_SIZE];

	if (crl == NULL) {
		gnutls_assert();
		return GNUTLS_E_INVALID_REQUEST;
	}

	snprintf(serial_name, sizeof(serial_name),
		 "tbsCertList.revokedCertificates.?%u.userCertificate",
		 indx + 1);
	snprintf(date_name, sizeof(date_name),
		 "tbsCertList.revokedCertificates.?%u.revocationDate",
		 indx + 1);

	_serial_size = *serial_size;
	result =
	    asn1_read_value(crl->crl, serial_name, serial, &_serial_size);

	*serial_size = _serial_size;
	if (result != ASN1_SUCCESS) {
		gnutls_assert();
		if (result == ASN1_ELEMENT_NOT_FOUND)
			return GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE;
		return _gnutls_asn2err(result);
	}

	if (t) {
		*t = _gnutls_x509_get_time(crl->crl, date_name, 0);
	}

	return 0;
}

/**
 * gnutls_x509_crl_iter_deinit:
 * @iter: The iterator to be deinitialized
 *
 * This function will deinitialize an iterator type.
 **/
void gnutls_x509_crl_iter_deinit(gnutls_x509_crl_iter_t iter)
{
	if (!iter)
		return;

	gnutls_free(iter);
}

/**
 * gnutls_x509_crl_iter_crt_serial:
 * @crl: should contain a #gnutls_x509_crl_t type
 * @iter: A pointer to an iterator (initially the iterator should be %NULL)
 * @serial: where the serial number will be copied
 * @serial_size: initially holds the size of serial
 * @t: if non null, will hold the time this certificate was revoked
 *
 * This function performs the same as gnutls_x509_crl_get_crt_serial(),
 * but reads sequentially and keeps state in the iterator 
 * between calls. That allows it to provide better performance in sequences 
 * with many elements (50000+).
 *
 * When past the last element is accessed %GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE
 * is returned and the iterator is reset.
 *
 * After use, the iterator must be deinitialized using gnutls_x509_crl_iter_deinit().
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 **/
int
gnutls_x509_crl_iter_crt_serial(gnutls_x509_crl_t crl,
				gnutls_x509_crl_iter_t *iter,
				unsigned char *serial,
				size_t * serial_size, time_t * t)
{

	int result, _serial_size;
	char serial_name[MAX_NAME_SIZE];
	char date_name[MAX_NAME_SIZE];

	if (crl == NULL || iter == NULL) {
		gnutls_assert();
		return GNUTLS_E_INVALID_REQUEST;
	}

	if (*iter == NULL) {
		*iter = gnutls_calloc(1, sizeof(struct gnutls_x509_crl_iter));
		if (*iter == NULL)
			return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);
	}

	if ((*iter)->rcache == NULL) {
		(*iter)->rcache = asn1_find_node (crl->crl, "tbsCertList.revokedCertificates.?1");
		(*iter)->rcache_idx = 1;
	} else {
		snprintf(serial_name, sizeof(serial_name),
			 "?%d", (*iter)->rcache_idx);
		(*iter)->rcache = asn1_find_node ((*iter)->rcache, serial_name);
	}
	if ((*iter)->rcache == NULL) {
		/* reset */
		(*iter)->rcache = NULL;
		return gnutls_assert_val(GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE);
	}

	snprintf(serial_name, sizeof(serial_name),
		 "?%d.userCertificate", (*iter)->rcache_idx);

	_serial_size = *serial_size;
	result =
	    asn1_read_value((*iter)->rcache, serial_name, serial, &_serial_size);

	*serial_size = _serial_size;
	if (result != ASN1_SUCCESS) {
		gnutls_assert();
		if (result == ASN1_ELEMENT_NOT_FOUND) {
			/* reset */
			(*iter)->rcache = NULL;
			return GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE;
		}
		return _gnutls_asn2err(result);
	}

	if (t) {
		snprintf(date_name, sizeof(date_name),
			 "?%d.revocationDate", (*iter)->rcache_idx);
		*t = _gnutls_x509_get_time((*iter)->rcache, date_name, 0);
	}

	(*iter)->rcache_idx++;

	return 0;
}

/**
 * gnutls_x509_crl_get_raw_issuer_dn:
 * @crl: should contain a gnutls_x509_crl_t type
 * @dn: will hold the starting point of the DN
 *
 * This function will return a pointer to the DER encoded DN structure
 * and the length.
 *
 * Returns: a negative error code on error, and (0) on success.
 *
 * Since: 2.12.0
 **/
int
gnutls_x509_crl_get_raw_issuer_dn(gnutls_x509_crl_t crl,
				  gnutls_datum_t * dn)
{
	if (crl->raw_issuer_dn.size != 0) {
		return _gnutls_set_datum(dn, crl->raw_issuer_dn.data,
					 crl->raw_issuer_dn.size);
	} else {
		return _gnutls_x509_get_raw_field(crl->crl, "tbsCertList.issuer.rdnSequence", dn);
	}
}

/**
 * gnutls_x509_crl_export:
 * @crl: Holds the revocation list
 * @format: the format of output params. One of PEM or DER.
 * @output_data: will contain a private key PEM or DER encoded
 * @output_data_size: holds the size of output_data (and will
 *   be replaced by the actual size of parameters)
 *
 * This function will export the revocation list to DER or PEM format.
 *
 * If the buffer provided is not long enough to hold the output, then
 * %GNUTLS_E_SHORT_MEMORY_BUFFER will be returned.
 *
 * If the structure is PEM encoded, it will have a header
 * of "BEGIN X509 CRL".
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 **/
int
gnutls_x509_crl_export(gnutls_x509_crl_t crl,
		       gnutls_x509_crt_fmt_t format, void *output_data,
		       size_t * output_data_size)
{
	if (crl == NULL) {
		gnutls_assert();
		return GNUTLS_E_INVALID_REQUEST;
	}

	return _gnutls_x509_export_int(crl->crl, format, PEM_CRL,
				       output_data, output_data_size);
}

/**
 * gnutls_x509_crl_export2:
 * @crl: Holds the revocation list
 * @format: the format of output params. One of PEM or DER.
 * @out: will contain a private key PEM or DER encoded
 *
 * This function will export the revocation list to DER or PEM format.
 *
 * The output buffer is allocated using gnutls_malloc().
 *
 * If the structure is PEM encoded, it will have a header
 * of "BEGIN X509 CRL".
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since 3.1.3
 **/
int
gnutls_x509_crl_export2(gnutls_x509_crl_t crl,
			gnutls_x509_crt_fmt_t format, gnutls_datum_t * out)
{
	if (crl == NULL) {
		gnutls_assert();
		return GNUTLS_E_INVALID_REQUEST;
	}

	return _gnutls_x509_export_int2(crl->crl, format, PEM_CRL, out);
}

/*-
 * _gnutls_x509_crl_cpy - This function copies a gnutls_x509_crl_t type
 * @dest: The data where to copy
 * @src: The data to be copied
 *
 * This function will copy an X.509 certificate structure.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 -*/
int _gnutls_x509_crl_cpy(gnutls_x509_crl_t dest, gnutls_x509_crl_t src)
{
	int ret;
	gnutls_datum_t tmp;

	ret = gnutls_x509_crl_export2(src, GNUTLS_X509_FMT_DER, &tmp);
	if (ret < 0)
		return gnutls_assert_val(ret);

	ret = gnutls_x509_crl_import(dest, &tmp, GNUTLS_X509_FMT_DER);

	gnutls_free(tmp.data);

	if (ret < 0) {
		gnutls_assert();
		return ret;
	}

	return 0;

}

static int
_get_authority_key_id(gnutls_x509_crl_t cert, ASN1_TYPE * c2,
		      unsigned int *critical)
{
	int ret;
	gnutls_datum_t id;

	*c2 = ASN1_TYPE_EMPTY;

	if (cert == NULL) {
		gnutls_assert();
		return GNUTLS_E_INVALID_REQUEST;
	}

	if ((ret =
	     _gnutls_x509_crl_get_extension(cert, "2.5.29.35", 0, &id,
					    critical)) < 0) {
		return gnutls_assert_val(ret);
	}

	if (id.size == 0 || id.data == NULL) {
		gnutls_assert();
		return GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE;
	}

	ret = asn1_create_element
	    (_gnutls_get_pkix(), "PKIX1.AuthorityKeyIdentifier", c2);
	if (ret != ASN1_SUCCESS) {
		gnutls_assert();
		_gnutls_free_datum(&id);
		return _gnutls_asn2err(ret);
	}

	ret = _asn1_strict_der_decode(c2, id.data, id.size, NULL);
	_gnutls_free_datum(&id);

	if (ret != ASN1_SUCCESS) {
		gnutls_assert();
		asn1_delete_structure(c2);
		return _gnutls_asn2err(ret);
	}

	return 0;
}

/**
 * gnutls_x509_crl_get_authority_key_gn_serial:
 * @crl: should contain a #gnutls_x509_crl_t type
 * @seq: specifies the sequence number of the alt name (0 for the first one, 1 for the second etc.)
 * @alt: is the place where the alternative name will be copied to
 * @alt_size: holds the size of alt.
 * @alt_type: holds the type of the alternative name (one of gnutls_x509_subject_alt_name_t).
 * @serial: buffer to store the serial number (may be null)
 * @serial_size: Holds the size of the serial field (may be null)
 * @critical: will be non-zero if the extension is marked as critical (may be null)
 *
 * This function will return the X.509 authority key
 * identifier when stored as a general name (authorityCertIssuer) 
 * and serial number.
 *
 * Because more than one general names might be stored
 * @seq can be used as a counter to request them all until 
 * %GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE is returned.
 *
 * Returns: Returns 0 on success, or an error code.
 *
 * Since: 3.0
 **/
int
gnutls_x509_crl_get_authority_key_gn_serial(gnutls_x509_crl_t crl,
					    unsigned int seq,
					    void *alt,
					    size_t * alt_size,
					    unsigned int *alt_type,
					    void *serial,
					    size_t * serial_size,
					    unsigned int *critical)
{
	int ret, result, len;
	ASN1_TYPE c2;

	ret = _get_authority_key_id(crl, &c2, critical);
	if (ret < 0)
		return gnutls_assert_val(ret);

	ret =
	    _gnutls_parse_general_name(c2, "authorityCertIssuer", seq, alt,
				       alt_size, alt_type, 0);
	if (ret < 0) {
		ret = gnutls_assert_val(ret);
		goto fail;
	}

	if (serial) {
		len = *serial_size;
		result =
		    asn1_read_value(c2, "authorityCertSerialNumber",
				    serial, &len);

		*serial_size = len;

		if (result < 0) {
			ret = _gnutls_asn2err(result);
			goto fail;
		}

	}

	ret = 0;

      fail:
	asn1_delete_structure(&c2);

	return ret;
}


/**
 * gnutls_x509_crl_get_authority_key_id:
 * @crl: should contain a #gnutls_x509_crl_t type
 * @id: The place where the identifier will be copied
 * @id_size: Holds the size of the result field.
 * @critical: will be non-zero if the extension is marked as critical
 *   (may be null)
 *
 * This function will return the CRL authority's key identifier.  This
 * is obtained by the X.509 Authority Key identifier extension field
 * (2.5.29.35).  Note that this function 
 * only returns the keyIdentifier field of the extension and
 * %GNUTLS_E_X509_UNSUPPORTED_EXTENSION, if the extension contains
 * the name and serial number of the certificate. In that case
 * gnutls_x509_crl_get_authority_key_gn_serial() may be used.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error code in case of an error.
 *
 * Since: 2.8.0
 **/
int
gnutls_x509_crl_get_authority_key_id(gnutls_x509_crl_t crl, void *id,
				     size_t * id_size,
				     unsigned int *critical)
{
	int result, len, ret;
	ASN1_TYPE c2;

	ret = _get_authority_key_id(crl, &c2, critical);
	if (ret < 0)
		return gnutls_assert_val(ret);

	len = *id_size;
	result = asn1_read_value(c2, "keyIdentifier", id, &len);

	*id_size = len;
	asn1_delete_structure(&c2);

	if (result == ASN1_VALUE_NOT_FOUND
	    || result == ASN1_ELEMENT_NOT_FOUND)
		return
		    gnutls_assert_val(GNUTLS_E_X509_UNSUPPORTED_EXTENSION);

	if (result != ASN1_SUCCESS) {
		gnutls_assert();
		return _gnutls_asn2err(result);
	}

	return 0;
}

/**
 * gnutls_x509_crl_get_number:
 * @crl: should contain a #gnutls_x509_crl_t type
 * @ret: The place where the number will be copied
 * @ret_size: Holds the size of the result field.
 * @critical: will be non-zero if the extension is marked as critical
 *   (may be null)
 *
 * This function will return the CRL number extension.  This is
 * obtained by the CRL Number extension field (2.5.29.20).
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error code in case of an error.
 *
 * Since: 2.8.0
 **/
int
gnutls_x509_crl_get_number(gnutls_x509_crl_t crl, void *ret,
			   size_t * ret_size, unsigned int *critical)
{
	int result;
	gnutls_datum_t id;

	if (crl == NULL) {
		gnutls_assert();
		return GNUTLS_E_INVALID_REQUEST;
	}

	if (ret)
		memset(ret, 0, *ret_size);
	else
		*ret_size = 0;

	if ((result =
	     _gnutls_x509_crl_get_extension(crl, "2.5.29.20", 0, &id,
					    critical)) < 0) {
		return result;
	}

	if (id.size == 0 || id.data == NULL) {
		gnutls_assert();
		return GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE;
	}

	result =
	    _gnutls_x509_ext_extract_number(ret, ret_size, id.data,
					    id.size);

	_gnutls_free_datum(&id);

	if (result < 0) {
		gnutls_assert();
		return result;
	}

	return 0;
}

/**
 * gnutls_x509_crl_get_extension_oid:
 * @crl: should contain a #gnutls_x509_crl_t type
 * @indx: Specifies which extension OID to send, use (0) to get the first one.
 * @oid: a pointer to store the OID (may be null)
 * @sizeof_oid: initially holds the size of @oid
 *
 * This function will return the requested extension OID in the CRL.
 * The extension OID will be stored as a string in the provided
 * buffer.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error code in case of an error.  If your have reached the
 *   last extension available %GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE
 *   will be returned.
 *
 * Since: 2.8.0
 **/
int
gnutls_x509_crl_get_extension_oid(gnutls_x509_crl_t crl, unsigned indx,
				  void *oid, size_t * sizeof_oid)
{
	int result;

	if (crl == NULL) {
		gnutls_assert();
		return GNUTLS_E_INVALID_REQUEST;
	}

	result =
	    _gnutls_x509_crl_get_extension_oid(crl, indx, oid, sizeof_oid);
	if (result < 0) {
		return result;
	}

	return 0;

}

/**
 * gnutls_x509_crl_get_extension_info:
 * @crl: should contain a #gnutls_x509_crl_t type
 * @indx: Specifies which extension OID to send, use (0) to get the first one.
 * @oid: a pointer to store the OID
 * @sizeof_oid: initially holds the maximum size of @oid, on return
 *   holds actual size of @oid.
 * @critical: output variable with critical flag, may be NULL.
 *
 * This function will return the requested extension OID in the CRL,
 * and the critical flag for it.  The extension OID will be stored as
 * a string in the provided buffer.  Use
 * gnutls_x509_crl_get_extension_data() to extract the data.
 *
 * If the buffer provided is not long enough to hold the output, then
 * *@sizeof_oid is updated and %GNUTLS_E_SHORT_MEMORY_BUFFER will be
 * returned.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error code in case of an error.  If your have reached the
 *   last extension available %GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE
 *   will be returned.
 *
 * Since: 2.8.0
 **/
int
gnutls_x509_crl_get_extension_info(gnutls_x509_crl_t crl, unsigned indx,
				   void *oid, size_t * sizeof_oid,
				   unsigned int *critical)
{
	int result;
	char str_critical[10];
	char name[MAX_NAME_SIZE];
	int len;

	if (!crl) {
		gnutls_assert();
		return GNUTLS_E_INVALID_REQUEST;
	}

	snprintf(name, sizeof(name),
		 "tbsCertList.crlExtensions.?%u.extnID", indx + 1);

	len = *sizeof_oid;
	result = asn1_read_value(crl->crl, name, oid, &len);
	*sizeof_oid = len;

	if (result == ASN1_ELEMENT_NOT_FOUND)
		return GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE;
	else if (result != ASN1_SUCCESS) {
		gnutls_assert();
		return _gnutls_asn2err(result);
	}

	snprintf(name, sizeof(name),
		 "tbsCertList.crlExtensions.?%u.critical", indx + 1);
	len = sizeof(str_critical);
	result = asn1_read_value(crl->crl, name, str_critical, &len);
	if (result != ASN1_SUCCESS) {
		gnutls_assert();
		return _gnutls_asn2err(result);
	}

	if (critical) {
		if (str_critical[0] == 'T')
			*critical = 1;
		else
			*critical = 0;
	}

	return 0;

}

/**
 * gnutls_x509_crl_get_extension_data:
 * @crl: should contain a #gnutls_x509_crl_t type
 * @indx: Specifies which extension OID to send. Use (0) to get the first one.
 * @data: a pointer to a structure to hold the data (may be null)
 * @sizeof_data: initially holds the size of @oid
 *
 * This function will return the requested extension data in the CRL.
 * The extension data will be stored as a string in the provided
 * buffer.
 *
 * Use gnutls_x509_crl_get_extension_info() to extract the OID and
 * critical flag.  Use gnutls_x509_crl_get_extension_info() instead,
 * if you want to get data indexed by the extension OID rather than
 * sequence.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error code in case of an error.  If your have reached the
 *   last extension available %GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE
 *   will be returned.
 *
 * Since: 2.8.0
 **/
int
gnutls_x509_crl_get_extension_data(gnutls_x509_crl_t crl, unsigned indx,
				   void *data, size_t * sizeof_data)
{
	int result, len;
	char name[MAX_NAME_SIZE];

	if (!crl) {
		gnutls_assert();
		return GNUTLS_E_INVALID_REQUEST;
	}

	snprintf(name, sizeof(name),
		 "tbsCertList.crlExtensions.?%u.extnValue", indx + 1);

	len = *sizeof_data;
	result = asn1_read_value(crl->crl, name, data, &len);
	*sizeof_data = len;

	if (result == ASN1_ELEMENT_NOT_FOUND)
		return GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE;
	else if (result < 0) {
		gnutls_assert();
		return _gnutls_asn2err(result);
	}

	return 0;
}

/**
 * gnutls_x509_crl_list_import2:
 * @crls: Will contain the parsed crl list.
 * @size: It will contain the size of the list.
 * @data: The PEM encoded CRL.
 * @format: One of DER or PEM.
 * @flags: must be (0) or an OR'd sequence of gnutls_certificate_import_flags.
 *
 * This function will convert the given PEM encoded CRL list
 * to the native gnutls_x509_crl_t format. The output will be stored
 * in @crls.  They will be automatically initialized.
 *
 * If the Certificate is PEM encoded it should have a header of "X509
 * CRL".
 *
 * Returns: the number of certificates read or a negative error value.
 *
 * Since: 3.0
 **/
int
gnutls_x509_crl_list_import2(gnutls_x509_crl_t ** crls,
			     unsigned int *size,
			     const gnutls_datum_t * data,
			     gnutls_x509_crt_fmt_t format,
			     unsigned int flags)
{
	unsigned int init = 1024;
	int ret;

	*crls = gnutls_malloc(sizeof(gnutls_x509_crl_t) * init);
	if (*crls == NULL) {
		gnutls_assert();
		return GNUTLS_E_MEMORY_ERROR;
	}

	ret =
	    gnutls_x509_crl_list_import(*crls, &init, data, format,
					flags | GNUTLS_X509_CRT_LIST_IMPORT_FAIL_IF_EXCEED);
	if (ret == GNUTLS_E_SHORT_MEMORY_BUFFER) {
		*crls =
		    gnutls_realloc_fast(*crls,
					sizeof(gnutls_x509_crl_t) * init);
		if (*crls == NULL) {
			gnutls_assert();
			return GNUTLS_E_MEMORY_ERROR;
		}

		ret =
		    gnutls_x509_crl_list_import(*crls, &init, data, format,
						flags);
	}

	if (ret < 0) {
		gnutls_free(*crls);
		*crls = NULL;
		return ret;
	}

	*size = init;
	return 0;
}

/**
 * gnutls_x509_crl_list_import:
 * @crls: Indicates where the parsed CRLs will be copied to. Must not be initialized.
 * @crl_max: Initially must hold the maximum number of crls. It will be updated with the number of crls available.
 * @data: The PEM encoded CRLs
 * @format: One of DER or PEM.
 * @flags: must be (0) or an OR'd sequence of gnutls_certificate_import_flags.
 *
 * This function will convert the given PEM encoded CRL list
 * to the native gnutls_x509_crl_t format. The output will be stored
 * in @crls.  They will be automatically initialized.
 *
 * If the Certificate is PEM encoded it should have a header of "X509 CRL".
 *
 * Returns: the number of certificates read or a negative error value.
 *
 * Since: 3.0
 **/
int
gnutls_x509_crl_list_import(gnutls_x509_crl_t * crls,
			    unsigned int *crl_max,
			    const gnutls_datum_t * data,
			    gnutls_x509_crt_fmt_t format,
			    unsigned int flags)
{
	int size;
	const char *ptr;
	gnutls_datum_t tmp;
	int ret, nocopy = 0;
	unsigned int count = 0, j;

	if (format == GNUTLS_X509_FMT_DER) {
		if (*crl_max < 1) {
			*crl_max = 1;
			return GNUTLS_E_SHORT_MEMORY_BUFFER;
		}

		count = 1;	/* import only the first one */

		ret = gnutls_x509_crl_init(&crls[0]);
		if (ret < 0) {
			gnutls_assert();
			goto error;
		}

		ret = gnutls_x509_crl_import(crls[0], data, format);
		if (ret < 0) {
			gnutls_assert();
			goto error;
		}

		*crl_max = 1;
		return 1;
	}

	/* move to the certificate
	 */
	ptr = memmem(data->data, data->size,
		     PEM_CRL_SEP, sizeof(PEM_CRL_SEP) - 1);
	if (ptr == NULL) {
		gnutls_assert();
		return GNUTLS_E_BASE64_DECODING_ERROR;
	}

	count = 0;

	do {
		if (count >= *crl_max) {
			if (!
			    (flags &
			     GNUTLS_X509_CRT_LIST_IMPORT_FAIL_IF_EXCEED)) {
				break;
			} else if (nocopy == 0) {
				for (j = 0; j < count; j++)
					gnutls_x509_crl_deinit(crls[j]);
				nocopy = 1;
			}
		}

		if (!nocopy) {
			ret = gnutls_x509_crl_init(&crls[count]);
			if (ret < 0) {
				gnutls_assert();
				goto error;
			}

			tmp.data = (void *) ptr;
			tmp.size =
			    data->size - (ptr - (char *) data->data);
			ret =
			    gnutls_x509_crl_import(crls[count], &tmp,
						   GNUTLS_X509_FMT_PEM);
			if (ret < 0) {
				gnutls_assert();
				count++;
				goto error;
			}
		}

		/* now we move ptr after the pem header 
		 */
		ptr++;
		/* find the next certificate (if any)
		 */
		size = data->size - (ptr - (char *) data->data);

		if (size > 0) {
			ptr =
			    memmem(ptr, size, PEM_CRL_SEP,
				   sizeof(PEM_CRL_SEP) - 1);
		} else
			ptr = NULL;

		count++;
	}
	while (ptr != NULL);

	*crl_max = count;

	if (nocopy == 0)
		return count;
	else
		return GNUTLS_E_SHORT_MEMORY_BUFFER;

      error:
	for (j = 0; j < count; j++)
		gnutls_x509_crl_deinit(crls[j]);
	return ret;
}