aboutsummaryrefslogtreecommitdiff
path: root/include/mbedtls/x509_crt.h
blob: 3f1a1e7619d2323e07462710a3dcdcbb3dd689ca (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
/**
 * \file x509_crt.h
 *
 * \brief X.509 certificate parsing and writing
 */
/*
 *  Copyright The Mbed TLS Contributors
 *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
 */
#ifndef MBEDTLS_X509_CRT_H
#define MBEDTLS_X509_CRT_H
#include "mbedtls/private_access.h"

#include "mbedtls/build_info.h"

#include "mbedtls/x509.h"
#include "mbedtls/x509_crl.h"
#include "mbedtls/bignum.h"

/**
 * \addtogroup x509_module
 * \{
 */

#ifdef __cplusplus
extern "C" {
#endif

/**
 * \name Structures and functions for parsing and writing X.509 certificates
 * \{
 */

/**
 * Container for an X.509 certificate. The certificate may be chained.
 *
 * Some fields of this structure are publicly readable. Do not modify
 * them except via Mbed TLS library functions: the effect of modifying
 * those fields or the data that those fields points to is unspecified.
 */
typedef struct mbedtls_x509_crt {
    int MBEDTLS_PRIVATE(own_buffer);                     /**< Indicates if \c raw is owned
                                                          *   by the structure or not.        */
    mbedtls_x509_buf raw;               /**< The raw certificate data (DER). */
    mbedtls_x509_buf tbs;               /**< The raw certificate body (DER). The part that is To Be Signed. */

    int version;                /**< The X.509 version. (1=v1, 2=v2, 3=v3) */
    mbedtls_x509_buf serial;            /**< Unique id for certificate issued by a specific CA. */
    mbedtls_x509_buf sig_oid;           /**< Signature algorithm, e.g. sha1RSA */

    mbedtls_x509_buf issuer_raw;        /**< The raw issuer data (DER). Used for quick comparison. */
    mbedtls_x509_buf subject_raw;       /**< The raw subject data (DER). Used for quick comparison. */

    mbedtls_x509_name issuer;           /**< The parsed issuer data (named information object). */
    mbedtls_x509_name subject;          /**< The parsed subject data (named information object). */

    mbedtls_x509_time valid_from;       /**< Start time of certificate validity. */
    mbedtls_x509_time valid_to;         /**< End time of certificate validity. */

    mbedtls_x509_buf pk_raw;
    mbedtls_pk_context pk;              /**< Container for the public key context. */

    mbedtls_x509_buf issuer_id;         /**< Optional X.509 v2/v3 issuer unique identifier. */
    mbedtls_x509_buf subject_id;        /**< Optional X.509 v2/v3 subject unique identifier. */
    mbedtls_x509_buf v3_ext;            /**< Optional X.509 v3 extensions.  */
    mbedtls_x509_sequence subject_alt_names; /**< Optional list of raw entries of Subject Alternative Names extension. These can be later parsed by mbedtls_x509_parse_subject_alt_name. */
    mbedtls_x509_buf subject_key_id;    /**< Optional X.509 v3 extension subject key identifier. */
    mbedtls_x509_authority authority_key_id;    /**< Optional X.509 v3 extension authority key identifier. */

    mbedtls_x509_sequence certificate_policies; /**< Optional list of certificate policies (Only anyPolicy is printed and enforced, however the rest of the policies are still listed). */

    int MBEDTLS_PRIVATE(ext_types);              /**< Bit string containing detected and parsed extensions */
    int MBEDTLS_PRIVATE(ca_istrue);              /**< Optional Basic Constraint extension value: 1 if this certificate belongs to a CA, 0 otherwise. */
    int MBEDTLS_PRIVATE(max_pathlen);            /**< Optional Basic Constraint extension value: The maximum path length to the root certificate. Path length is 1 higher than RFC 5280 'meaning', so 1+ */

    unsigned int MBEDTLS_PRIVATE(key_usage);     /**< Optional key usage extension value: See the values in x509.h */

    mbedtls_x509_sequence ext_key_usage; /**< Optional list of extended key usage OIDs. */

    unsigned char MBEDTLS_PRIVATE(ns_cert_type); /**< Optional Netscape certificate type extension value: See the values in x509.h */

    mbedtls_x509_buf MBEDTLS_PRIVATE(sig);               /**< Signature: hash of the tbs part signed with the private key. */
    mbedtls_md_type_t MBEDTLS_PRIVATE(sig_md);           /**< Internal representation of the MD algorithm of the signature algorithm, e.g. MBEDTLS_MD_SHA256 */
    mbedtls_pk_type_t MBEDTLS_PRIVATE(sig_pk);           /**< Internal representation of the Public Key algorithm of the signature algorithm, e.g. MBEDTLS_PK_RSA */
    void *MBEDTLS_PRIVATE(sig_opts);             /**< Signature options to be passed to mbedtls_pk_verify_ext(), e.g. for RSASSA-PSS */

    /** Next certificate in the linked list that constitutes the CA chain.
     * \p NULL indicates the end of the list.
     * Do not modify this field directly. */
    struct mbedtls_x509_crt *next;
}
mbedtls_x509_crt;

/**
 * Build flag from an algorithm/curve identifier (pk, md, ecp)
 * Since 0 is always XXX_NONE, ignore it.
 */
#define MBEDTLS_X509_ID_FLAG(id)   (1 << ((id) - 1))

/**
 * Security profile for certificate verification.
 *
 * All lists are bitfields, built by ORing flags from MBEDTLS_X509_ID_FLAG().
 *
 * The fields of this structure are part of the public API and can be
 * manipulated directly by applications. Future versions of the library may
 * add extra fields or reorder existing fields.
 *
 * You can create custom profiles by starting from a copy of
 * an existing profile, such as mbedtls_x509_crt_profile_default or
 * mbedtls_x509_ctr_profile_none and then tune it to your needs.
 *
 * For example to allow SHA-224 in addition to the default:
 *
 *  mbedtls_x509_crt_profile my_profile = mbedtls_x509_crt_profile_default;
 *  my_profile.allowed_mds |= MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA224 );
 *
 * Or to allow only RSA-3072+ with SHA-256:
 *
 *  mbedtls_x509_crt_profile my_profile = mbedtls_x509_crt_profile_none;
 *  my_profile.allowed_mds = MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA256 );
 *  my_profile.allowed_pks = MBEDTLS_X509_ID_FLAG( MBEDTLS_PK_RSA );
 *  my_profile.rsa_min_bitlen = 3072;
 */
typedef struct mbedtls_x509_crt_profile {
    uint32_t allowed_mds;       /**< MDs for signatures         */
    uint32_t allowed_pks;       /**< PK algs for public keys;
                                 *   this applies to all certificates
                                 *   in the provided chain.     */
    uint32_t allowed_curves;    /**< Elliptic curves for ECDSA  */
    uint32_t rsa_min_bitlen;    /**< Minimum size for RSA keys  */
}
mbedtls_x509_crt_profile;

#define MBEDTLS_X509_CRT_VERSION_1              0
#define MBEDTLS_X509_CRT_VERSION_2              1
#define MBEDTLS_X509_CRT_VERSION_3              2

#define MBEDTLS_X509_RFC5280_MAX_SERIAL_LEN 20
#define MBEDTLS_X509_RFC5280_UTC_TIME_LEN   15

#if !defined(MBEDTLS_X509_MAX_FILE_PATH_LEN)
#define MBEDTLS_X509_MAX_FILE_PATH_LEN 512
#endif

/* This macro unfolds to the concatenation of macro invocations
 * X509_CRT_ERROR_INFO( error code,
 *                             error code as string,
 *                             human readable description )
 * where X509_CRT_ERROR_INFO is defined by the user.
 * See x509_crt.c for an example of how to use this. */
#define MBEDTLS_X509_CRT_ERROR_INFO_LIST                                  \
    X509_CRT_ERROR_INFO(MBEDTLS_X509_BADCERT_EXPIRED,            \
                        "MBEDTLS_X509_BADCERT_EXPIRED",          \
                        "The certificate validity has expired") \
    X509_CRT_ERROR_INFO(MBEDTLS_X509_BADCERT_REVOKED,            \
                        "MBEDTLS_X509_BADCERT_REVOKED",          \
                        "The certificate has been revoked (is on a CRL)") \
    X509_CRT_ERROR_INFO(MBEDTLS_X509_BADCERT_CN_MISMATCH,                  \
                        "MBEDTLS_X509_BADCERT_CN_MISMATCH",                \
                        "The certificate Common Name (CN) does not match with the expected CN") \
    X509_CRT_ERROR_INFO(MBEDTLS_X509_BADCERT_NOT_TRUSTED,                             \
                        "MBEDTLS_X509_BADCERT_NOT_TRUSTED",                           \
                        "The certificate is not correctly signed by the trusted CA") \
    X509_CRT_ERROR_INFO(MBEDTLS_X509_BADCRL_NOT_TRUSTED,                      \
                        "MBEDTLS_X509_BADCRL_NOT_TRUSTED",                    \
                        "The CRL is not correctly signed by the trusted CA") \
    X509_CRT_ERROR_INFO(MBEDTLS_X509_BADCRL_EXPIRED,    \
                        "MBEDTLS_X509_BADCRL_EXPIRED",  \
                        "The CRL is expired")          \
    X509_CRT_ERROR_INFO(MBEDTLS_X509_BADCERT_MISSING,   \
                        "MBEDTLS_X509_BADCERT_MISSING", \
                        "Certificate was missing")     \
    X509_CRT_ERROR_INFO(MBEDTLS_X509_BADCERT_SKIP_VERIFY,         \
                        "MBEDTLS_X509_BADCERT_SKIP_VERIFY",       \
                        "Certificate verification was skipped")  \
    X509_CRT_ERROR_INFO(MBEDTLS_X509_BADCERT_OTHER,                          \
                        "MBEDTLS_X509_BADCERT_OTHER",                        \
                        "Other reason (can be used by verify callback)")    \
    X509_CRT_ERROR_INFO(MBEDTLS_X509_BADCERT_FUTURE,                         \
                        "MBEDTLS_X509_BADCERT_FUTURE",                       \
                        "The certificate validity starts in the future")    \
    X509_CRT_ERROR_INFO(MBEDTLS_X509_BADCRL_FUTURE,     \
                        "MBEDTLS_X509_BADCRL_FUTURE",   \
                        "The CRL is from the future")  \
    X509_CRT_ERROR_INFO(MBEDTLS_X509_BADCERT_KEY_USAGE,                      \
                        "MBEDTLS_X509_BADCERT_KEY_USAGE",                    \
                        "Usage does not match the keyUsage extension")      \
    X509_CRT_ERROR_INFO(MBEDTLS_X509_BADCERT_EXT_KEY_USAGE,                       \
                        "MBEDTLS_X509_BADCERT_EXT_KEY_USAGE",                     \
                        "Usage does not match the extendedKeyUsage extension")   \
    X509_CRT_ERROR_INFO(MBEDTLS_X509_BADCERT_NS_CERT_TYPE,                        \
                        "MBEDTLS_X509_BADCERT_NS_CERT_TYPE",                      \
                        "Usage does not match the nsCertType extension")         \
    X509_CRT_ERROR_INFO(MBEDTLS_X509_BADCERT_BAD_MD,                              \
                        "MBEDTLS_X509_BADCERT_BAD_MD",                            \
                        "The certificate is signed with an unacceptable hash.")  \
    X509_CRT_ERROR_INFO(MBEDTLS_X509_BADCERT_BAD_PK,                                                  \
                        "MBEDTLS_X509_BADCERT_BAD_PK",                                                \
                        "The certificate is signed with an unacceptable PK alg (eg RSA vs ECDSA).")  \
    X509_CRT_ERROR_INFO(MBEDTLS_X509_BADCERT_BAD_KEY,                                                            \
                        "MBEDTLS_X509_BADCERT_BAD_KEY",                                                          \
                        "The certificate is signed with an unacceptable key (eg bad curve, RSA too short).")    \
    X509_CRT_ERROR_INFO(MBEDTLS_X509_BADCRL_BAD_MD,                          \
                        "MBEDTLS_X509_BADCRL_BAD_MD",                        \
                        "The CRL is signed with an unacceptable hash.")     \
    X509_CRT_ERROR_INFO(MBEDTLS_X509_BADCRL_BAD_PK,                                            \
                        "MBEDTLS_X509_BADCRL_BAD_PK",                                          \
                        "The CRL is signed with an unacceptable PK alg (eg RSA vs ECDSA).")   \
    X509_CRT_ERROR_INFO(MBEDTLS_X509_BADCRL_BAD_KEY,                                                    \
                        "MBEDTLS_X509_BADCRL_BAD_KEY",                                                  \
                        "The CRL is signed with an unacceptable key (eg bad curve, RSA too short).")

/**
 * Container for writing a certificate (CRT)
 */
typedef struct mbedtls_x509write_cert {
    int MBEDTLS_PRIVATE(version);
    unsigned char MBEDTLS_PRIVATE(serial)[MBEDTLS_X509_RFC5280_MAX_SERIAL_LEN];
    size_t MBEDTLS_PRIVATE(serial_len);
    mbedtls_pk_context *MBEDTLS_PRIVATE(subject_key);
    mbedtls_pk_context *MBEDTLS_PRIVATE(issuer_key);
    mbedtls_asn1_named_data *MBEDTLS_PRIVATE(subject);
    mbedtls_asn1_named_data *MBEDTLS_PRIVATE(issuer);
    mbedtls_md_type_t MBEDTLS_PRIVATE(md_alg);
    char MBEDTLS_PRIVATE(not_before)[MBEDTLS_X509_RFC5280_UTC_TIME_LEN + 1];
    char MBEDTLS_PRIVATE(not_after)[MBEDTLS_X509_RFC5280_UTC_TIME_LEN + 1];
    mbedtls_asn1_named_data *MBEDTLS_PRIVATE(extensions);
}
mbedtls_x509write_cert;

/**
 * \brief           Set Subject Alternative Name
 *
 * \param ctx       Certificate context to use
 * \param san_list  List of SAN values
 *
 * \return          0 if successful, or MBEDTLS_ERR_X509_ALLOC_FAILED
 *
 * \note            "dnsName", "uniformResourceIdentifier", "IP address",
 *                  "otherName", and "DirectoryName", as defined in RFC 5280,
 *                  are supported.
 */
int mbedtls_x509write_crt_set_subject_alternative_name(mbedtls_x509write_cert *ctx,
                                                       const mbedtls_x509_san_list *san_list);

/**
 * Item in a verification chain: cert and flags for it
 */
typedef struct {
    mbedtls_x509_crt *MBEDTLS_PRIVATE(crt);
    uint32_t MBEDTLS_PRIVATE(flags);
} mbedtls_x509_crt_verify_chain_item;

/**
 * Max size of verification chain: end-entity + intermediates + trusted root
 */
#define MBEDTLS_X509_MAX_VERIFY_CHAIN_SIZE  (MBEDTLS_X509_MAX_INTERMEDIATE_CA + 2)

/**
 * Verification chain as built by \c mbedtls_crt_verify_chain()
 */
typedef struct {
    mbedtls_x509_crt_verify_chain_item MBEDTLS_PRIVATE(items)[MBEDTLS_X509_MAX_VERIFY_CHAIN_SIZE];
    unsigned MBEDTLS_PRIVATE(len);

#if defined(MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK)
    /* This stores the list of potential trusted signers obtained from
     * the CA callback used for the CRT verification, if configured.
     * We must track it somewhere because the callback passes its
     * ownership to the caller. */
    mbedtls_x509_crt *MBEDTLS_PRIVATE(trust_ca_cb_result);
#endif /* MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK */
} mbedtls_x509_crt_verify_chain;

#if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)

/**
 * \brief       Context for resuming X.509 verify operations
 */
typedef struct {
    /* for check_signature() */
    mbedtls_pk_restart_ctx MBEDTLS_PRIVATE(pk);

    /* for find_parent_in() */
    mbedtls_x509_crt *MBEDTLS_PRIVATE(parent); /* non-null iff parent_in in progress */
    mbedtls_x509_crt *MBEDTLS_PRIVATE(fallback_parent);
    int MBEDTLS_PRIVATE(fallback_signature_is_good);

    /* for find_parent() */
    int MBEDTLS_PRIVATE(parent_is_trusted); /* -1 if find_parent is not in progress */

    /* for verify_chain() */
    enum {
        x509_crt_rs_none,
        x509_crt_rs_find_parent,
    } MBEDTLS_PRIVATE(in_progress);  /* none if no operation is in progress */
    int MBEDTLS_PRIVATE(self_cnt);
    mbedtls_x509_crt_verify_chain MBEDTLS_PRIVATE(ver_chain);

} mbedtls_x509_crt_restart_ctx;

#else /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */

/* Now we can declare functions that take a pointer to that */
typedef void mbedtls_x509_crt_restart_ctx;

#endif /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */

#if defined(MBEDTLS_X509_CRT_PARSE_C)
/**
 * Default security profile. Should provide a good balance between security
 * and compatibility with current deployments.
 *
 * This profile permits:
 * - SHA2 hashes with at least 256 bits: SHA-256, SHA-384, SHA-512.
 * - Elliptic curves with 255 bits and above except secp256k1.
 * - RSA with 2048 bits and above.
 *
 * New minor versions of Mbed TLS may extend this profile, for example if
 * new algorithms are added to the library. New minor versions of Mbed TLS will
 * not reduce this profile unless serious security concerns require it.
 */
extern const mbedtls_x509_crt_profile mbedtls_x509_crt_profile_default;

/**
 * Expected next default profile. Recommended for new deployments.
 * Currently targets a 128-bit security level, except for allowing RSA-2048.
 * This profile may change at any time.
 */
extern const mbedtls_x509_crt_profile mbedtls_x509_crt_profile_next;

/**
 * NSA Suite B profile.
 */
extern const mbedtls_x509_crt_profile mbedtls_x509_crt_profile_suiteb;

/**
 * Empty profile that allows nothing. Useful as a basis for constructing
 * custom profiles.
 */
extern const mbedtls_x509_crt_profile mbedtls_x509_crt_profile_none;

/**
 * \brief          Parse a single DER formatted certificate and add it
 *                 to the end of the provided chained list.
 *
 * \note           If #MBEDTLS_USE_PSA_CRYPTO is enabled, the PSA crypto
 *                 subsystem must have been initialized by calling
 *                 psa_crypto_init() before calling this function.
 *
 * \param chain    The pointer to the start of the CRT chain to attach to.
 *                 When parsing the first CRT in a chain, this should point
 *                 to an instance of ::mbedtls_x509_crt initialized through
 *                 mbedtls_x509_crt_init().
 * \param buf      The buffer holding the DER encoded certificate.
 * \param buflen   The size in Bytes of \p buf.
 *
 * \note           This function makes an internal copy of the CRT buffer
 *                 \p buf. In particular, \p buf may be destroyed or reused
 *                 after this call returns. To avoid duplicating the CRT
 *                 buffer (at the cost of stricter lifetime constraints),
 *                 use mbedtls_x509_crt_parse_der_nocopy() instead.
 *
 * \return         \c 0 if successful.
 * \return         A negative error code on failure.
 */
int mbedtls_x509_crt_parse_der(mbedtls_x509_crt *chain,
                               const unsigned char *buf,
                               size_t buflen);

/**
 * \brief          The type of certificate extension callbacks.
 *
 *                 Callbacks of this type are passed to and used by the
 *                 mbedtls_x509_crt_parse_der_with_ext_cb() routine when
 *                 it encounters either an unsupported extension or a
 *                 "certificate policies" extension containing any
 *                 unsupported certificate policies.
 *                 Future versions of the library may invoke the callback
 *                 in other cases, if and when the need arises.
 *
 * \param p_ctx    An opaque context passed to the callback.
 * \param crt      The certificate being parsed.
 * \param oid      The OID of the extension.
 * \param critical Whether the extension is critical.
 * \param p        Pointer to the start of the extension value
 *                 (the content of the OCTET STRING).
 * \param end      End of extension value.
 *
 * \note           The callback must fail and return a negative error code
 *                 if it can not parse or does not support the extension.
 *                 When the callback fails to parse a critical extension
 *                 mbedtls_x509_crt_parse_der_with_ext_cb() also fails.
 *                 When the callback fails to parse a non critical extension
 *                 mbedtls_x509_crt_parse_der_with_ext_cb() simply skips
 *                 the extension and continues parsing.
 *
 * \return         \c 0 on success.
 * \return         A negative error code on failure.
 */
typedef int (*mbedtls_x509_crt_ext_cb_t)(void *p_ctx,
                                         mbedtls_x509_crt const *crt,
                                         mbedtls_x509_buf const *oid,
                                         int critical,
                                         const unsigned char *p,
                                         const unsigned char *end);

/**
 * \brief            Parse a single DER formatted certificate and add it
 *                   to the end of the provided chained list.
 *
 * \note             If #MBEDTLS_USE_PSA_CRYPTO is enabled, the PSA crypto
 *                   subsystem must have been initialized by calling
 *                   psa_crypto_init() before calling this function.
 *
 * \param chain      The pointer to the start of the CRT chain to attach to.
 *                   When parsing the first CRT in a chain, this should point
 *                   to an instance of ::mbedtls_x509_crt initialized through
 *                   mbedtls_x509_crt_init().
 * \param buf        The buffer holding the DER encoded certificate.
 * \param buflen     The size in Bytes of \p buf.
 * \param make_copy  When not zero this function makes an internal copy of the
 *                   CRT buffer \p buf. In particular, \p buf may be destroyed
 *                   or reused after this call returns.
 *                   When zero this function avoids duplicating the CRT buffer
 *                   by taking temporary ownership thereof until the CRT
 *                   is destroyed (like mbedtls_x509_crt_parse_der_nocopy())
 * \param cb         A callback invoked for every unsupported certificate
 *                   extension.
 * \param p_ctx      An opaque context passed to the callback.
 *
 * \note             This call is functionally equivalent to
 *                   mbedtls_x509_crt_parse_der(), and/or
 *                   mbedtls_x509_crt_parse_der_nocopy()
 *                   but it calls the callback with every unsupported
 *                   certificate extension and additionally the
 *                   "certificate policies" extension if it contains any
 *                   unsupported certificate policies.
 *                   The callback must return a negative error code if it
 *                   does not know how to handle such an extension.
 *                   When the callback fails to parse a critical extension
 *                   mbedtls_x509_crt_parse_der_with_ext_cb() also fails.
 *                   When the callback fails to parse a non critical extension
 *                   mbedtls_x509_crt_parse_der_with_ext_cb() simply skips
 *                   the extension and continues parsing.
 *                   Future versions of the library may invoke the callback
 *                   in other cases, if and when the need arises.
 *
 * \return           \c 0 if successful.
 * \return           A negative error code on failure.
 */
int mbedtls_x509_crt_parse_der_with_ext_cb(mbedtls_x509_crt *chain,
                                           const unsigned char *buf,
                                           size_t buflen,
                                           int make_copy,
                                           mbedtls_x509_crt_ext_cb_t cb,
                                           void *p_ctx);

/**
 * \brief          Parse a single DER formatted certificate and add it
 *                 to the end of the provided chained list. This is a
 *                 variant of mbedtls_x509_crt_parse_der() which takes
 *                 temporary ownership of the CRT buffer until the CRT
 *                 is destroyed.
 *
 * \note           If #MBEDTLS_USE_PSA_CRYPTO is enabled, the PSA crypto
 *                 subsystem must have been initialized by calling
 *                 psa_crypto_init() before calling this function.
 *
 * \param chain    The pointer to the start of the CRT chain to attach to.
 *                 When parsing the first CRT in a chain, this should point
 *                 to an instance of ::mbedtls_x509_crt initialized through
 *                 mbedtls_x509_crt_init().
 * \param buf      The address of the readable buffer holding the DER encoded
 *                 certificate to use. On success, this buffer must be
 *                 retained and not be changed for the lifetime of the
 *                 CRT chain \p chain, that is, until \p chain is destroyed
 *                 through a call to mbedtls_x509_crt_free().
 * \param buflen   The size in Bytes of \p buf.
 *
 * \note           This call is functionally equivalent to
 *                 mbedtls_x509_crt_parse_der(), but it avoids creating a
 *                 copy of the input buffer at the cost of stronger lifetime
 *                 constraints. This is useful in constrained environments
 *                 where duplication of the CRT cannot be tolerated.
 *
 * \return         \c 0 if successful.
 * \return         A negative error code on failure.
 */
int mbedtls_x509_crt_parse_der_nocopy(mbedtls_x509_crt *chain,
                                      const unsigned char *buf,
                                      size_t buflen);

/**
 * \brief          Parse one DER-encoded or one or more concatenated PEM-encoded
 *                 certificates and add them to the chained list.
 *
 *                 For CRTs in PEM encoding, the function parses permissively:
 *                 if at least one certificate can be parsed, the function
 *                 returns the number of certificates for which parsing failed
 *                 (hence \c 0 if all certificates were parsed successfully).
 *                 If no certificate could be parsed, the function returns
 *                 the first (negative) error encountered during parsing.
 *
 *                 PEM encoded certificates may be interleaved by other data
 *                 such as human readable descriptions of their content, as
 *                 long as the certificates are enclosed in the PEM specific
 *                 '-----{BEGIN/END} CERTIFICATE-----' delimiters.
 *
 * \note           If #MBEDTLS_USE_PSA_CRYPTO is enabled, the PSA crypto
 *                 subsystem must have been initialized by calling
 *                 psa_crypto_init() before calling this function.
 *
 * \param chain    The chain to which to add the parsed certificates.
 * \param buf      The buffer holding the certificate data in PEM or DER format.
 *                 For certificates in PEM encoding, this may be a concatenation
 *                 of multiple certificates; for DER encoding, the buffer must
 *                 comprise exactly one certificate.
 * \param buflen   The size of \p buf, including the terminating \c NULL byte
 *                 in case of PEM encoded data.
 *
 * \return         \c 0 if all certificates were parsed successfully.
 * \return         The (positive) number of certificates that couldn't
 *                 be parsed if parsing was partly successful (see above).
 * \return         A negative X509 or PEM error code otherwise.
 *
 */
int mbedtls_x509_crt_parse(mbedtls_x509_crt *chain, const unsigned char *buf, size_t buflen);

#if defined(MBEDTLS_FS_IO)
/**
 * \brief          Load one or more certificates and add them
 *                 to the chained list. Parses permissively. If some
 *                 certificates can be parsed, the result is the number
 *                 of failed certificates it encountered. If none complete
 *                 correctly, the first error is returned.
 *
 * \note           If #MBEDTLS_USE_PSA_CRYPTO is enabled, the PSA crypto
 *                 subsystem must have been initialized by calling
 *                 psa_crypto_init() before calling this function.
 *
 * \param chain    points to the start of the chain
 * \param path     filename to read the certificates from
 *
 * \return         0 if all certificates parsed successfully, a positive number
 *                 if partly successful or a specific X509 or PEM error code
 */
int mbedtls_x509_crt_parse_file(mbedtls_x509_crt *chain, const char *path);

/**
 * \brief          Load one or more certificate files from a path and add them
 *                 to the chained list. Parses permissively. If some
 *                 certificates can be parsed, the result is the number
 *                 of failed certificates it encountered. If none complete
 *                 correctly, the first error is returned.
 *
 * \param chain    points to the start of the chain
 * \param path     directory / folder to read the certificate files from
 *
 * \return         0 if all certificates parsed successfully, a positive number
 *                 if partly successful or a specific X509 or PEM error code
 */
int mbedtls_x509_crt_parse_path(mbedtls_x509_crt *chain, const char *path);

#endif /* MBEDTLS_FS_IO */

#if !defined(MBEDTLS_X509_REMOVE_INFO)
/**
 * \brief          Returns an informational string about the
 *                 certificate.
 *
 * \param buf      Buffer to write to
 * \param size     Maximum size of buffer
 * \param prefix   A line prefix
 * \param crt      The X509 certificate to represent
 *
 * \return         The length of the string written (not including the
 *                 terminated nul byte), or a negative error code.
 */
int mbedtls_x509_crt_info(char *buf, size_t size, const char *prefix,
                          const mbedtls_x509_crt *crt);

/**
 * \brief          Returns an informational string about the
 *                 verification status of a certificate.
 *
 * \param buf      Buffer to write to
 * \param size     Maximum size of buffer
 * \param prefix   A line prefix
 * \param flags    Verification flags created by mbedtls_x509_crt_verify()
 *
 * \return         The length of the string written (not including the
 *                 terminated nul byte), or a negative error code.
 */
int mbedtls_x509_crt_verify_info(char *buf, size_t size, const char *prefix,
                                 uint32_t flags);
#endif /* !MBEDTLS_X509_REMOVE_INFO */

/**
 * \brief          Verify a chain of certificates.
 *
 *                 The verify callback is a user-supplied callback that
 *                 can clear / modify / add flags for a certificate. If set,
 *                 the verification callback is called for each
 *                 certificate in the chain (from the trust-ca down to the
 *                 presented crt). The parameters for the callback are:
 *                 (void *parameter, mbedtls_x509_crt *crt, int certificate_depth,
 *                 int *flags). With the flags representing current flags for
 *                 that specific certificate and the certificate depth from
 *                 the bottom (Peer cert depth = 0).
 *
 *                 All flags left after returning from the callback
 *                 are also returned to the application. The function should
 *                 return 0 for anything (including invalid certificates)
 *                 other than fatal error, as a non-zero return code
 *                 immediately aborts the verification process. For fatal
 *                 errors, a specific error code should be used (different
 *                 from MBEDTLS_ERR_X509_CERT_VERIFY_FAILED which should not
 *                 be returned at this point), or MBEDTLS_ERR_X509_FATAL_ERROR
 *                 can be used if no better code is available.
 *
 * \note           In case verification failed, the results can be displayed
 *                 using \c mbedtls_x509_crt_verify_info()
 *
 * \note           Same as \c mbedtls_x509_crt_verify_with_profile() with the
 *                 default security profile.
 *
 * \note           It is your responsibility to provide up-to-date CRLs for
 *                 all trusted CAs. If no CRL is provided for the CA that was
 *                 used to sign the certificate, CRL verification is skipped
 *                 silently, that is *without* setting any flag.
 *
 * \note           The \c trust_ca list can contain two types of certificates:
 *                 (1) those of trusted root CAs, so that certificates
 *                 chaining up to those CAs will be trusted, and (2)
 *                 self-signed end-entity certificates to be trusted (for
 *                 specific peers you know) - in that case, the self-signed
 *                 certificate doesn't need to have the CA bit set.
 *
 * \param crt      The certificate chain to be verified.
 * \param trust_ca The list of trusted CAs.
 * \param ca_crl   The list of CRLs for trusted CAs.
 * \param cn       The expected Common Name. This will be checked to be
 *                 present in the certificate's subjectAltNames extension or,
 *                 if this extension is absent, as a CN component in its
 *                 Subject name. DNS names and IP addresses are fully
 *                 supported, while the URI subtype is partially supported:
 *                 only exact matching, without any normalization procedures
 *                 described in 7.4 of RFC5280, will result in a positive
 *                 URI verification.
 *                 This may be \c NULL if the CN need not be verified.
 * \param flags    The address at which to store the result of the verification.
 *                 If the verification couldn't be completed, the flag value is
 *                 set to (uint32_t) -1.
 * \param f_vrfy   The verification callback to use. See the documentation
 *                 of mbedtls_x509_crt_verify() for more information.
 * \param p_vrfy   The context to be passed to \p f_vrfy.
 *
 * \return         \c 0 if the chain is valid with respect to the
 *                 passed CN, CAs, CRLs and security profile.
 * \return         #MBEDTLS_ERR_X509_CERT_VERIFY_FAILED in case the
 *                 certificate chain verification failed. In this case,
 *                 \c *flags will have one or more
 *                 \c MBEDTLS_X509_BADCERT_XXX or \c MBEDTLS_X509_BADCRL_XXX
 *                 flags set.
 * \return         Another negative error code in case of a fatal error
 *                 encountered during the verification process.
 */
int mbedtls_x509_crt_verify(mbedtls_x509_crt *crt,
                            mbedtls_x509_crt *trust_ca,
                            mbedtls_x509_crl *ca_crl,
                            const char *cn, uint32_t *flags,
                            int (*f_vrfy)(void *, mbedtls_x509_crt *, int, uint32_t *),
                            void *p_vrfy);

/**
 * \brief          Verify a chain of certificates with respect to
 *                 a configurable security profile.
 *
 * \note           Same as \c mbedtls_x509_crt_verify(), but with explicit
 *                 security profile.
 *
 * \note           The restrictions on keys (RSA minimum size, allowed curves
 *                 for ECDSA) apply to all certificates: trusted root,
 *                 intermediate CAs if any, and end entity certificate.
 *
 * \param crt      The certificate chain to be verified.
 * \param trust_ca The list of trusted CAs.
 * \param ca_crl   The list of CRLs for trusted CAs.
 * \param profile  The security profile to use for the verification.
 * \param cn       The expected Common Name. This may be \c NULL if the
 *                 CN need not be verified.
 * \param flags    The address at which to store the result of the verification.
 *                 If the verification couldn't be completed, the flag value is
 *                 set to (uint32_t) -1.
 * \param f_vrfy   The verification callback to use. See the documentation
 *                 of mbedtls_x509_crt_verify() for more information.
 * \param p_vrfy   The context to be passed to \p f_vrfy.
 *
 * \return         \c 0 if the chain is valid with respect to the
 *                 passed CN, CAs, CRLs and security profile.
 * \return         #MBEDTLS_ERR_X509_CERT_VERIFY_FAILED in case the
 *                 certificate chain verification failed. In this case,
 *                 \c *flags will have one or more
 *                 \c MBEDTLS_X509_BADCERT_XXX or \c MBEDTLS_X509_BADCRL_XXX
 *                 flags set.
 * \return         Another negative error code in case of a fatal error
 *                 encountered during the verification process.
 */
int mbedtls_x509_crt_verify_with_profile(mbedtls_x509_crt *crt,
                                         mbedtls_x509_crt *trust_ca,
                                         mbedtls_x509_crl *ca_crl,
                                         const mbedtls_x509_crt_profile *profile,
                                         const char *cn, uint32_t *flags,
                                         int (*f_vrfy)(void *, mbedtls_x509_crt *, int, uint32_t *),
                                         void *p_vrfy);

/**
 * \brief          Restartable version of \c mbedtls_crt_verify_with_profile()
 *
 * \note           Performs the same job as \c mbedtls_crt_verify_with_profile()
 *                 but can return early and restart according to the limit
 *                 set with \c mbedtls_ecp_set_max_ops() to reduce blocking.
 *
 * \param crt      The certificate chain to be verified.
 * \param trust_ca The list of trusted CAs.
 * \param ca_crl   The list of CRLs for trusted CAs.
 * \param profile  The security profile to use for the verification.
 * \param cn       The expected Common Name. This may be \c NULL if the
 *                 CN need not be verified.
 * \param flags    The address at which to store the result of the verification.
 *                 If the verification couldn't be completed, the flag value is
 *                 set to (uint32_t) -1.
 * \param f_vrfy   The verification callback to use. See the documentation
 *                 of mbedtls_x509_crt_verify() for more information.
 * \param p_vrfy   The context to be passed to \p f_vrfy.
 * \param rs_ctx   The restart context to use. This may be set to \c NULL
 *                 to disable restartable ECC.
 *
 * \return         See \c mbedtls_crt_verify_with_profile(), or
 * \return         #MBEDTLS_ERR_ECP_IN_PROGRESS if maximum number of
 *                 operations was reached: see \c mbedtls_ecp_set_max_ops().
 */
int mbedtls_x509_crt_verify_restartable(mbedtls_x509_crt *crt,
                                        mbedtls_x509_crt *trust_ca,
                                        mbedtls_x509_crl *ca_crl,
                                        const mbedtls_x509_crt_profile *profile,
                                        const char *cn, uint32_t *flags,
                                        int (*f_vrfy)(void *, mbedtls_x509_crt *, int, uint32_t *),
                                        void *p_vrfy,
                                        mbedtls_x509_crt_restart_ctx *rs_ctx);

/**
 * \brief               The type of trusted certificate callbacks.
 *
 *                      Callbacks of this type are passed to and used by the CRT
 *                      verification routine mbedtls_x509_crt_verify_with_ca_cb()
 *                      when looking for trusted signers of a given certificate.
 *
 *                      On success, the callback returns a list of trusted
 *                      certificates to be considered as potential signers
 *                      for the input certificate.
 *
 * \param p_ctx         An opaque context passed to the callback.
 * \param child         The certificate for which to search a potential signer.
 *                      This will point to a readable certificate.
 * \param candidate_cas The address at which to store the address of the first
 *                      entry in the generated linked list of candidate signers.
 *                      This will not be \c NULL.
 *
 * \note                The callback must only return a non-zero value on a
 *                      fatal error. If, in contrast, the search for a potential
 *                      signer completes without a single candidate, the
 *                      callback must return \c 0 and set \c *candidate_cas
 *                      to \c NULL.
 *
 * \return              \c 0 on success. In this case, \c *candidate_cas points
 *                      to a heap-allocated linked list of instances of
 *                      ::mbedtls_x509_crt, and ownership of this list is passed
 *                      to the caller.
 * \return              A negative error code on failure.
 */
typedef int (*mbedtls_x509_crt_ca_cb_t)(void *p_ctx,
                                        mbedtls_x509_crt const *child,
                                        mbedtls_x509_crt **candidate_cas);

#if defined(MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK)
/**
 * \brief          Version of \c mbedtls_x509_crt_verify_with_profile() which
 *                 uses a callback to acquire the list of trusted CA
 *                 certificates.
 *
 * \param crt      The certificate chain to be verified.
 * \param f_ca_cb  The callback to be used to query for potential signers
 *                 of a given child certificate. See the documentation of
 *                 ::mbedtls_x509_crt_ca_cb_t for more information.
 * \param p_ca_cb  The opaque context to be passed to \p f_ca_cb.
 * \param profile  The security profile for the verification.
 * \param cn       The expected Common Name. This may be \c NULL if the
 *                 CN need not be verified.
 * \param flags    The address at which to store the result of the verification.
 *                 If the verification couldn't be completed, the flag value is
 *                 set to (uint32_t) -1.
 * \param f_vrfy   The verification callback to use. See the documentation
 *                 of mbedtls_x509_crt_verify() for more information.
 * \param p_vrfy   The context to be passed to \p f_vrfy.
 *
 * \return         See \c mbedtls_crt_verify_with_profile().
 */
int mbedtls_x509_crt_verify_with_ca_cb(mbedtls_x509_crt *crt,
                                       mbedtls_x509_crt_ca_cb_t f_ca_cb,
                                       void *p_ca_cb,
                                       const mbedtls_x509_crt_profile *profile,
                                       const char *cn, uint32_t *flags,
                                       int (*f_vrfy)(void *, mbedtls_x509_crt *, int, uint32_t *),
                                       void *p_vrfy);

#endif /* MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK */

/**
 * \brief          Check usage of certificate against keyUsage extension.
 *
 * \param crt      Leaf certificate used.
 * \param usage    Intended usage(s) (eg MBEDTLS_X509_KU_KEY_ENCIPHERMENT
 *                 before using the certificate to perform an RSA key
 *                 exchange).
 *
 * \note           Except for decipherOnly and encipherOnly, a bit set in the
 *                 usage argument means this bit MUST be set in the
 *                 certificate. For decipherOnly and encipherOnly, it means
 *                 that bit MAY be set.
 *
 * \return         0 is these uses of the certificate are allowed,
 *                 MBEDTLS_ERR_X509_BAD_INPUT_DATA if the keyUsage extension
 *                 is present but does not match the usage argument.
 *
 * \note           You should only call this function on leaf certificates, on
 *                 (intermediate) CAs the keyUsage extension is automatically
 *                 checked by \c mbedtls_x509_crt_verify().
 */
int mbedtls_x509_crt_check_key_usage(const mbedtls_x509_crt *crt,
                                     unsigned int usage);

/**
 * \brief           Check usage of certificate against extendedKeyUsage.
 *
 * \param crt       Leaf certificate used.
 * \param usage_oid Intended usage (eg MBEDTLS_OID_SERVER_AUTH or
 *                  MBEDTLS_OID_CLIENT_AUTH).
 * \param usage_len Length of usage_oid (eg given by MBEDTLS_OID_SIZE()).
 *
 * \return          0 if this use of the certificate is allowed,
 *                  MBEDTLS_ERR_X509_BAD_INPUT_DATA if not.
 *
 * \note            Usually only makes sense on leaf certificates.
 */
int mbedtls_x509_crt_check_extended_key_usage(const mbedtls_x509_crt *crt,
                                              const char *usage_oid,
                                              size_t usage_len);

#if defined(MBEDTLS_X509_CRL_PARSE_C)
/**
 * \brief          Verify the certificate revocation status
 *
 * \param crt      a certificate to be verified
 * \param crl      the CRL to verify against
 *
 * \return         1 if the certificate is revoked, 0 otherwise
 *
 */
int mbedtls_x509_crt_is_revoked(const mbedtls_x509_crt *crt, const mbedtls_x509_crl *crl);
#endif /* MBEDTLS_X509_CRL_PARSE_C */

/**
 * \brief          Initialize a certificate (chain)
 *
 * \param crt      Certificate chain to initialize
 */
void mbedtls_x509_crt_init(mbedtls_x509_crt *crt);

/**
 * \brief          Unallocate all certificate data
 *
 * \param crt      Certificate chain to free
 */
void mbedtls_x509_crt_free(mbedtls_x509_crt *crt);

#if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
/**
 * \brief           Initialize a restart context
 */
void mbedtls_x509_crt_restart_init(mbedtls_x509_crt_restart_ctx *ctx);

/**
 * \brief           Free the components of a restart context
 */
void mbedtls_x509_crt_restart_free(mbedtls_x509_crt_restart_ctx *ctx);
#endif /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */
#endif /* MBEDTLS_X509_CRT_PARSE_C */

/**
 * \brief               Query certificate for given extension type
 *
 * \param[in] ctx       Certificate context to be queried, must not be \c NULL
 * \param ext_type      Extension type being queried for, must be a valid
 *                      extension type. Must be one of the MBEDTLS_X509_EXT_XXX
 *                      values
 *
 * \return              0 if the given extension type is not present,
 *                      non-zero otherwise
 */
static inline int mbedtls_x509_crt_has_ext_type(const mbedtls_x509_crt *ctx,
                                                int ext_type)
{
    return ctx->MBEDTLS_PRIVATE(ext_types) & ext_type;
}

/** \} name Structures and functions for parsing and writing X.509 certificates */

#if defined(MBEDTLS_X509_CRT_WRITE_C)
/**
 * \brief           Initialize a CRT writing context
 *
 * \param ctx       CRT context to initialize
 */
void mbedtls_x509write_crt_init(mbedtls_x509write_cert *ctx);

/**
 * \brief           Set the version for a Certificate
 *                  Default: MBEDTLS_X509_CRT_VERSION_3
 *
 * \param ctx       CRT context to use
 * \param version   version to set (MBEDTLS_X509_CRT_VERSION_1, MBEDTLS_X509_CRT_VERSION_2 or
 *                                  MBEDTLS_X509_CRT_VERSION_3)
 */
void mbedtls_x509write_crt_set_version(mbedtls_x509write_cert *ctx, int version);

#if defined(MBEDTLS_BIGNUM_C) && !defined(MBEDTLS_DEPRECATED_REMOVED)
/**
 * \brief           Set the serial number for a Certificate.
 *
 * \deprecated      This function is deprecated and will be removed in a
 *                  future version of the library. Please use
 *                  mbedtls_x509write_crt_set_serial_raw() instead.
 *
 * \note            Even though the MBEDTLS_BIGNUM_C guard looks redundant since
 *                  X509 depends on PK and PK depends on BIGNUM, this emphasizes
 *                  a direct dependency between X509 and BIGNUM which is going
 *                  to be deprecated in the future.
 *
 * \param ctx       CRT context to use
 * \param serial    serial number to set
 *
 * \return          0 if successful
 */
int MBEDTLS_DEPRECATED mbedtls_x509write_crt_set_serial(
    mbedtls_x509write_cert *ctx, const mbedtls_mpi *serial);
#endif // MBEDTLS_BIGNUM_C && !MBEDTLS_DEPRECATED_REMOVED

/**
 * \brief           Set the serial number for a Certificate.
 *
 * \param ctx          CRT context to use
 * \param serial       A raw array of bytes containing the serial number in big
 *                     endian format
 * \param serial_len   Length of valid bytes (expressed in bytes) in \p serial
 *                     input buffer
 *
 * \return          0 if successful, or
 *                  MBEDTLS_ERR_X509_BAD_INPUT_DATA if the provided input buffer
 *                  is too big (longer than MBEDTLS_X509_RFC5280_MAX_SERIAL_LEN)
 */
int mbedtls_x509write_crt_set_serial_raw(mbedtls_x509write_cert *ctx,
                                         unsigned char *serial, size_t serial_len);

/**
 * \brief           Set the validity period for a Certificate
 *                  Timestamps should be in string format for UTC timezone
 *                  i.e. "YYYYMMDDhhmmss"
 *                  e.g. "20131231235959" for December 31st 2013
 *                       at 23:59:59
 *
 * \param ctx       CRT context to use
 * \param not_before    not_before timestamp
 * \param not_after     not_after timestamp
 *
 * \return          0 if timestamp was parsed successfully, or
 *                  a specific error code
 */
int mbedtls_x509write_crt_set_validity(mbedtls_x509write_cert *ctx, const char *not_before,
                                       const char *not_after);

/**
 * \brief           Set the issuer name for a Certificate
 *                  Issuer names should contain a comma-separated list
 *                  of OID types and values:
 *                  e.g. "C=UK,O=ARM,CN=Mbed TLS CA"
 *
 * \param ctx           CRT context to use
 * \param issuer_name   issuer name to set
 *
 * \return          0 if issuer name was parsed successfully, or
 *                  a specific error code
 */
int mbedtls_x509write_crt_set_issuer_name(mbedtls_x509write_cert *ctx,
                                          const char *issuer_name);

/**
 * \brief           Set the subject name for a Certificate
 *                  Subject names should contain a comma-separated list
 *                  of OID types and values:
 *                  e.g. "C=UK,O=ARM,CN=Mbed TLS Server 1"
 *
 * \param ctx           CRT context to use
 * \param subject_name  subject name to set
 *
 * \return          0 if subject name was parsed successfully, or
 *                  a specific error code
 */
int mbedtls_x509write_crt_set_subject_name(mbedtls_x509write_cert *ctx,
                                           const char *subject_name);

/**
 * \brief           Set the subject public key for the certificate
 *
 * \param ctx       CRT context to use
 * \param key       public key to include
 */
void mbedtls_x509write_crt_set_subject_key(mbedtls_x509write_cert *ctx, mbedtls_pk_context *key);

/**
 * \brief           Set the issuer key used for signing the certificate
 *
 * \param ctx       CRT context to use
 * \param key       private key to sign with
 */
void mbedtls_x509write_crt_set_issuer_key(mbedtls_x509write_cert *ctx, mbedtls_pk_context *key);

/**
 * \brief           Set the MD algorithm to use for the signature
 *                  (e.g. MBEDTLS_MD_SHA1)
 *
 * \param ctx       CRT context to use
 * \param md_alg    MD algorithm to use
 */
void mbedtls_x509write_crt_set_md_alg(mbedtls_x509write_cert *ctx, mbedtls_md_type_t md_alg);

/**
 * \brief           Generic function to add to or replace an extension in the
 *                  CRT
 *
 * \param ctx       CRT context to use
 * \param oid       OID of the extension
 * \param oid_len   length of the OID
 * \param critical  if the extension is critical (per the RFC's definition)
 * \param val       value of the extension OCTET STRING
 * \param val_len   length of the value data
 *
 * \return          0 if successful, or a MBEDTLS_ERR_X509_ALLOC_FAILED
 */
int mbedtls_x509write_crt_set_extension(mbedtls_x509write_cert *ctx,
                                        const char *oid, size_t oid_len,
                                        int critical,
                                        const unsigned char *val, size_t val_len);

/**
 * \brief           Set the basicConstraints extension for a CRT
 *
 * \param ctx       CRT context to use
 * \param is_ca     is this a CA certificate
 * \param max_pathlen   maximum length of certificate chains below this
 *                      certificate (only for CA certificates, -1 is
 *                      unlimited)
 *
 * \return          0 if successful, or a MBEDTLS_ERR_X509_ALLOC_FAILED
 */
int mbedtls_x509write_crt_set_basic_constraints(mbedtls_x509write_cert *ctx,
                                                int is_ca, int max_pathlen);

#if defined(MBEDTLS_MD_CAN_SHA1)
/**
 * \brief           Set the subjectKeyIdentifier extension for a CRT
 *                  Requires that mbedtls_x509write_crt_set_subject_key() has been
 *                  called before
 *
 * \param ctx       CRT context to use
 *
 * \return          0 if successful, or a MBEDTLS_ERR_X509_ALLOC_FAILED
 */
int mbedtls_x509write_crt_set_subject_key_identifier(mbedtls_x509write_cert *ctx);

/**
 * \brief           Set the authorityKeyIdentifier extension for a CRT
 *                  Requires that mbedtls_x509write_crt_set_issuer_key() has been
 *                  called before
 *
 * \param ctx       CRT context to use
 *
 * \return          0 if successful, or a MBEDTLS_ERR_X509_ALLOC_FAILED
 */
int mbedtls_x509write_crt_set_authority_key_identifier(mbedtls_x509write_cert *ctx);
#endif /* MBEDTLS_MD_CAN_SHA1 */

/**
 * \brief           Set the Key Usage Extension flags
 *                  (e.g. MBEDTLS_X509_KU_DIGITAL_SIGNATURE | MBEDTLS_X509_KU_KEY_CERT_SIGN)
 *
 * \param ctx       CRT context to use
 * \param key_usage key usage flags to set
 *
 * \return          0 if successful, or MBEDTLS_ERR_X509_ALLOC_FAILED
 */
int mbedtls_x509write_crt_set_key_usage(mbedtls_x509write_cert *ctx,
                                        unsigned int key_usage);

/**
 * \brief           Set the Extended Key Usage Extension
 *                  (e.g. MBEDTLS_OID_SERVER_AUTH)
 *
 * \param ctx       CRT context to use
 * \param exts      extended key usage extensions to set, a sequence of
 *                  MBEDTLS_ASN1_OID objects
 *
 * \return          0 if successful, or MBEDTLS_ERR_X509_ALLOC_FAILED
 */
int mbedtls_x509write_crt_set_ext_key_usage(mbedtls_x509write_cert *ctx,
                                            const mbedtls_asn1_sequence *exts);

/**
 * \brief           Set the Netscape Cert Type flags
 *                  (e.g. MBEDTLS_X509_NS_CERT_TYPE_SSL_CLIENT | MBEDTLS_X509_NS_CERT_TYPE_EMAIL)
 *
 * \param ctx           CRT context to use
 * \param ns_cert_type  Netscape Cert Type flags to set
 *
 * \return          0 if successful, or MBEDTLS_ERR_X509_ALLOC_FAILED
 */
int mbedtls_x509write_crt_set_ns_cert_type(mbedtls_x509write_cert *ctx,
                                           unsigned char ns_cert_type);

/**
 * \brief           Free the contents of a CRT write context
 *
 * \param ctx       CRT context to free
 */
void mbedtls_x509write_crt_free(mbedtls_x509write_cert *ctx);

/**
 * \brief           Write a built up certificate to a X509 DER structure
 *                  Note: data is written at the end of the buffer! Use the
 *                        return value to determine where you should start
 *                        using the buffer
 *
 * \param ctx       certificate to write away
 * \param buf       buffer to write to
 * \param size      size of the buffer
 * \param f_rng     RNG function. This must not be \c NULL.
 * \param p_rng     RNG parameter
 *
 * \return          length of data written if successful, or a specific
 *                  error code
 *
 * \note            \p f_rng is used for the signature operation.
 */
int mbedtls_x509write_crt_der(mbedtls_x509write_cert *ctx, unsigned char *buf, size_t size,
                              int (*f_rng)(void *, unsigned char *, size_t),
                              void *p_rng);

#if defined(MBEDTLS_PEM_WRITE_C)
/**
 * \brief           Write a built up certificate to a X509 PEM string
 *
 * \param ctx       certificate to write away
 * \param buf       buffer to write to
 * \param size      size of the buffer
 * \param f_rng     RNG function. This must not be \c NULL.
 * \param p_rng     RNG parameter
 *
 * \return          0 if successful, or a specific error code
 *
 * \note            \p f_rng is used for the signature operation.
 */
int mbedtls_x509write_crt_pem(mbedtls_x509write_cert *ctx, unsigned char *buf, size_t size,
                              int (*f_rng)(void *, unsigned char *, size_t),
                              void *p_rng);
#endif /* MBEDTLS_PEM_WRITE_C */
#endif /* MBEDTLS_X509_CRT_WRITE_C */

/** \} addtogroup x509_module */

#ifdef __cplusplus
}
#endif

#endif /* mbedtls_x509_crt.h */