aboutsummaryrefslogtreecommitdiffstats
path: root/crypto/x509v3/v3_purp.c
blob: 2b06dba0539812dc894fa5ad02125a9f4b5ca1f9 (plain) (blame)
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
/*
 * Copyright 1999-2020 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the OpenSSL license (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

#include <stdio.h>
#include "internal/cryptlib.h"
#include "internal/numbers.h"
#include <openssl/x509v3.h>
#include <openssl/x509_vfy.h>
#include "crypto/x509.h"
#include "../x509/x509_local.h" /* for x509_signing_allowed() */
#include "internal/tsan_assist.h"

static void x509v3_cache_extensions(X509 *x);

static int check_ssl_ca(const X509 *x);
static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x,
                                    int ca);
static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x,
                                    int ca);
static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x,
                                       int ca);
static int purpose_smime(const X509 *x, int ca);
static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x,
                                    int ca);
static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x,
                                       int ca);
static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x,
                                  int ca);
static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x,
                                        int ca);
static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca);
static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca);

static int xp_cmp(const X509_PURPOSE *const *a, const X509_PURPOSE *const *b);
static void xptable_free(X509_PURPOSE *p);

static X509_PURPOSE xstandard[] = {
    {X509_PURPOSE_SSL_CLIENT, X509_TRUST_SSL_CLIENT, 0,
     check_purpose_ssl_client, "SSL client", "sslclient", NULL},
    {X509_PURPOSE_SSL_SERVER, X509_TRUST_SSL_SERVER, 0,
     check_purpose_ssl_server, "SSL server", "sslserver", NULL},
    {X509_PURPOSE_NS_SSL_SERVER, X509_TRUST_SSL_SERVER, 0,
     check_purpose_ns_ssl_server, "Netscape SSL server", "nssslserver", NULL},
    {X509_PURPOSE_SMIME_SIGN, X509_TRUST_EMAIL, 0, check_purpose_smime_sign,
     "S/MIME signing", "smimesign", NULL},
    {X509_PURPOSE_SMIME_ENCRYPT, X509_TRUST_EMAIL, 0,
     check_purpose_smime_encrypt, "S/MIME encryption", "smimeencrypt", NULL},
    {X509_PURPOSE_CRL_SIGN, X509_TRUST_COMPAT, 0, check_purpose_crl_sign,
     "CRL signing", "crlsign", NULL},
    {X509_PURPOSE_ANY, X509_TRUST_DEFAULT, 0, no_check, "Any Purpose", "any",
     NULL},
    {X509_PURPOSE_OCSP_HELPER, X509_TRUST_COMPAT, 0, ocsp_helper,
     "OCSP helper", "ocsphelper", NULL},
    {X509_PURPOSE_TIMESTAMP_SIGN, X509_TRUST_TSA, 0,
     check_purpose_timestamp_sign, "Time Stamp signing", "timestampsign",
     NULL},
};

#define X509_PURPOSE_COUNT OSSL_NELEM(xstandard)

static STACK_OF(X509_PURPOSE) *xptable = NULL;

static int xp_cmp(const X509_PURPOSE *const *a, const X509_PURPOSE *const *b)
{
    return (*a)->purpose - (*b)->purpose;
}

/*
 * As much as I'd like to make X509_check_purpose use a "const" X509* I
 * really can't because it does recalculate hashes and do other non-const
 * things.
 */
int X509_check_purpose(X509 *x, int id, int ca)
{
    int idx;
    const X509_PURPOSE *pt;

    x509v3_cache_extensions(x);
    if (x->ex_flags & EXFLAG_INVALID)
        return -1;

    /* Return if side-effect only call */
    if (id == -1)
        return 1;
    idx = X509_PURPOSE_get_by_id(id);
    if (idx == -1)
        return -1;
    pt = X509_PURPOSE_get0(idx);
    return pt->check_purpose(pt, x, ca);
}

int X509_PURPOSE_set(int *p, int purpose)
{
    if (X509_PURPOSE_get_by_id(purpose) == -1) {
        X509V3err(X509V3_F_X509_PURPOSE_SET, X509V3_R_INVALID_PURPOSE);
        return 0;
    }
    *p = purpose;
    return 1;
}

int X509_PURPOSE_get_count(void)
{
    if (!xptable)
        return X509_PURPOSE_COUNT;
    return sk_X509_PURPOSE_num(xptable) + X509_PURPOSE_COUNT;
}

X509_PURPOSE *X509_PURPOSE_get0(int idx)
{
    if (idx < 0)
        return NULL;
    if (idx < (int)X509_PURPOSE_COUNT)
        return xstandard + idx;
    return sk_X509_PURPOSE_value(xptable, idx - X509_PURPOSE_COUNT);
}

int X509_PURPOSE_get_by_sname(const char *sname)
{
    int i;
    X509_PURPOSE *xptmp;
    for (i = 0; i < X509_PURPOSE_get_count(); i++) {
        xptmp = X509_PURPOSE_get0(i);
        if (strcmp(xptmp->sname, sname) == 0)
            return i;
    }
    return -1;
}

int X509_PURPOSE_get_by_id(int purpose)
{
    X509_PURPOSE tmp;
    int idx;

    if ((purpose >= X509_PURPOSE_MIN) && (purpose <= X509_PURPOSE_MAX))
        return purpose - X509_PURPOSE_MIN;
    if (xptable == NULL)
        return -1;
    tmp.purpose = purpose;
    idx = sk_X509_PURPOSE_find(xptable, &tmp);
    if (idx < 0)
        return -1;
    return idx + X509_PURPOSE_COUNT;
}

int X509_PURPOSE_add(int id, int trust, int flags,
                     int (*ck) (const X509_PURPOSE *, const X509 *, int),
                     const char *name, const char *sname, void *arg)
{
    int idx;
    X509_PURPOSE *ptmp;
    /*
     * This is set according to what we change: application can't set it
     */
    flags &= ~X509_PURPOSE_DYNAMIC;
    /* This will always be set for application modified trust entries */
    flags |= X509_PURPOSE_DYNAMIC_NAME;
    /* Get existing entry if any */
    idx = X509_PURPOSE_get_by_id(id);
    /* Need a new entry */
    if (idx == -1) {
        if ((ptmp = OPENSSL_malloc(sizeof(*ptmp))) == NULL) {
            X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE);
            return 0;
        }
        ptmp->flags = X509_PURPOSE_DYNAMIC;
    } else
        ptmp = X509_PURPOSE_get0(idx);

    /* OPENSSL_free existing name if dynamic */
    if (ptmp->flags & X509_PURPOSE_DYNAMIC_NAME) {
        OPENSSL_free(ptmp->name);
        OPENSSL_free(ptmp->sname);
    }
    /* dup supplied name */
    ptmp->name = OPENSSL_strdup(name);
    ptmp->sname = OPENSSL_strdup(sname);
    if (!ptmp->name || !ptmp->sname) {
        X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE);
        goto err;
    }
    /* Keep the dynamic flag of existing entry */
    ptmp->flags &= X509_PURPOSE_DYNAMIC;
    /* Set all other flags */
    ptmp->flags |= flags;

    ptmp->purpose = id;
    ptmp->trust = trust;
    ptmp->check_purpose = ck;
    ptmp->usr_data = arg;

    /* If its a new entry manage the dynamic table */
    if (idx == -1) {
        if (xptable == NULL
            && (xptable = sk_X509_PURPOSE_new(xp_cmp)) == NULL) {
            X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE);
            goto err;
        }
        if (!sk_X509_PURPOSE_push(xptable, ptmp)) {
            X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE);
            goto err;
        }
    }
    return 1;
 err:
    if (idx == -1) {
        OPENSSL_free(ptmp->name);
        OPENSSL_free(ptmp->sname);
        OPENSSL_free(ptmp);
    }
    return 0;
}

static void xptable_free(X509_PURPOSE *p)
{
    if (!p)
        return;
    if (p->flags & X509_PURPOSE_DYNAMIC) {
        if (p->flags & X509_PURPOSE_DYNAMIC_NAME) {
            OPENSSL_free(p->name);
            OPENSSL_free(p->sname);
        }
        OPENSSL_free(p);
    }
}

void X509_PURPOSE_cleanup(void)
{
    sk_X509_PURPOSE_pop_free(xptable, xptable_free);
    xptable = NULL;
}

int X509_PURPOSE_get_id(const X509_PURPOSE *xp)
{
    return xp->purpose;
}

char *X509_PURPOSE_get0_name(const X509_PURPOSE *xp)
{
    return xp->name;
}

char *X509_PURPOSE_get0_sname(const X509_PURPOSE *xp)
{
    return xp->sname;
}

int X509_PURPOSE_get_trust(const X509_PURPOSE *xp)
{
    return xp->trust;
}

static int nid_cmp(const int *a, const int *b)
{
    return *a - *b;
}

DECLARE_OBJ_BSEARCH_CMP_FN(int, int, nid);
IMPLEMENT_OBJ_BSEARCH_CMP_FN(int, int, nid);

int X509_supported_extension(X509_EXTENSION *ex)
{
    /*
     * This table is a list of the NIDs of supported extensions: that is
     * those which are used by the verify process. If an extension is
     * critical and doesn't appear in this list then the verify process will
     * normally reject the certificate. The list must be kept in numerical
     * order because it will be searched using bsearch.
     */

    static const int supported_nids[] = {
        NID_netscape_cert_type, /* 71 */
        NID_key_usage,          /* 83 */
        NID_subject_alt_name,   /* 85 */
        NID_basic_constraints,  /* 87 */
        NID_certificate_policies, /* 89 */
        NID_crl_distribution_points, /* 103 */
        NID_ext_key_usage,      /* 126 */
#ifndef OPENSSL_NO_RFC3779
        NID_sbgp_ipAddrBlock,   /* 290 */
        NID_sbgp_autonomousSysNum, /* 291 */
#endif
        NID_policy_constraints, /* 401 */
        NID_proxyCertInfo,      /* 663 */
        NID_name_constraints,   /* 666 */
        NID_policy_mappings,    /* 747 */
        NID_inhibit_any_policy  /* 748 */
    };

    int ex_nid = OBJ_obj2nid(X509_EXTENSION_get_object(ex));

    if (ex_nid == NID_undef)
        return 0;

    if (OBJ_bsearch_nid(&ex_nid, supported_nids, OSSL_NELEM(supported_nids)))
        return 1;
    return 0;
}

static int setup_dp(X509 *x, DIST_POINT *dp)
{
    X509_NAME *iname = NULL;
    int i;

    if (dp->reasons) {
        if (dp->reasons->length > 0)
            dp->dp_reasons = dp->reasons->data[0];
        if (dp->reasons->length > 1)
            dp->dp_reasons |= (dp->reasons->data[1] << 8);
        dp->dp_reasons &= CRLDP_ALL_REASONS;
    } else
        dp->dp_reasons = CRLDP_ALL_REASONS;
    if (!dp->distpoint || (dp->distpoint->type != 1))
        return 1;
    for (i = 0; i < sk_GENERAL_NAME_num(dp->CRLissuer); i++) {
        GENERAL_NAME *gen = sk_GENERAL_NAME_value(dp->CRLissuer, i);
        if (gen->type == GEN_DIRNAME) {
            iname = gen->d.directoryName;
            break;
        }
    }
    if (!iname)
        iname = X509_get_issuer_name(x);

    return DIST_POINT_set_dpname(dp->distpoint, iname);
}

static int setup_crldp(X509 *x)
{
    int i;

    x->crldp = X509_get_ext_d2i(x, NID_crl_distribution_points, &i, NULL);
    if (x->crldp == NULL && i != -1)
        return 0;
    for (i = 0; i < sk_DIST_POINT_num(x->crldp); i++) {
        if (!setup_dp(x, sk_DIST_POINT_value(x->crldp, i)))
            return 0;
    }
    return 1;
}

/* Check that issuer public key algorithm matches subject signature algorithm */
static int check_sig_alg_match(const EVP_PKEY *pkey, const X509 *subject)
{
    int pkey_nid;

    if (pkey == NULL)
        return X509_V_ERR_NO_ISSUER_PUBLIC_KEY;
    if (OBJ_find_sigid_algs(OBJ_obj2nid(subject->cert_info.signature.algorithm),
                            NULL, &pkey_nid) == 0)
        return X509_V_ERR_UNSUPPORTED_SIGNATURE_ALGORITHM;
    if (EVP_PKEY_type(pkey_nid) != EVP_PKEY_base_id(pkey))
        return X509_V_ERR_SIGNATURE_ALGORITHM_MISMATCH;
    return X509_V_OK;
}

#define V1_ROOT (EXFLAG_V1|EXFLAG_SS)
#define ku_reject(x, usage) \
        (((x)->ex_flags & EXFLAG_KUSAGE) && !((x)->ex_kusage & (usage)))
#define xku_reject(x, usage) \
        (((x)->ex_flags & EXFLAG_XKUSAGE) && !((x)->ex_xkusage & (usage)))
#define ns_reject(x, usage) \
        (((x)->ex_flags & EXFLAG_NSCERT) && !((x)->ex_nscert & (usage)))

static void x509v3_cache_extensions(X509 *x)
{
    BASIC_CONSTRAINTS *bs;
    PROXY_CERT_INFO_EXTENSION *pci;
    ASN1_BIT_STRING *usage;
    ASN1_BIT_STRING *ns;
    EXTENDED_KEY_USAGE *extusage;
    X509_EXTENSION *ex;
    int i;

#ifdef tsan_ld_acq
    /* fast lock-free check, see end of the function for details. */
    if (tsan_ld_acq((TSAN_QUALIFIER int *)&x->ex_cached))
        return;
#endif

    CRYPTO_THREAD_write_lock(x->lock);
    if (x->ex_flags & EXFLAG_SET) {
        CRYPTO_THREAD_unlock(x->lock);
        return;
    }

    if (!X509_digest(x, EVP_sha1(), x->sha1_hash, NULL))
        x->ex_flags |= EXFLAG_INVALID;
    /* V1 should mean no extensions ... */
    if (!X509_get_version(x))
        x->ex_flags |= EXFLAG_V1;
    /* Handle basic constraints */
    if ((bs = X509_get_ext_d2i(x, NID_basic_constraints, &i, NULL))) {
        if (bs->ca)
            x->ex_flags |= EXFLAG_CA;
        if (bs->pathlen) {
            if (bs->pathlen->type == V_ASN1_NEG_INTEGER) {
                x->ex_flags |= EXFLAG_INVALID;
                x->ex_pathlen = 0;
            } else {
                x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen);
                if (!bs->ca && x->ex_pathlen != 0) {
                    x->ex_flags |= EXFLAG_INVALID;
                    x->ex_pathlen = 0;
                }
            }
        } else
            x->ex_pathlen = -1;
        BASIC_CONSTRAINTS_free(bs);
        x->ex_flags |= EXFLAG_BCONS;
    } else if (i != -1) {
        x->ex_flags |= EXFLAG_INVALID;
    }
    /* Handle proxy certificates */
    if ((pci = X509_get_ext_d2i(x, NID_proxyCertInfo, &i, NULL))) {
        if (x->ex_flags & EXFLAG_CA
            || X509_get_ext_by_NID(x, NID_subject_alt_name, -1) >= 0
            || X509_get_ext_by_NID(x, NID_issuer_alt_name, -1) >= 0) {
            x->ex_flags |= EXFLAG_INVALID;
        }
        if (pci->pcPathLengthConstraint) {
            x->ex_pcpathlen = ASN1_INTEGER_get(pci->pcPathLengthConstraint);
        } else
            x->ex_pcpathlen = -1;
        PROXY_CERT_INFO_EXTENSION_free(pci);
        x->ex_flags |= EXFLAG_PROXY;
    } else if (i != -1) {
        x->ex_flags |= EXFLAG_INVALID;
    }
    /* Handle key usage */
    if ((usage = X509_get_ext_d2i(x, NID_key_usage, &i, NULL))) {
        if (usage->length > 0) {
            x->ex_kusage = usage->data[0];
            if (usage->length > 1)
                x->ex_kusage |= usage->data[1] << 8;
        } else
            x->ex_kusage = 0;
        x->ex_flags |= EXFLAG_KUSAGE;
        ASN1_BIT_STRING_free(usage);
    } else if (i != -1) {
        x->ex_flags |= EXFLAG_INVALID;
    }
    x->ex_xkusage = 0;
    if ((extusage = X509_get_ext_d2i(x, NID_ext_key_usage, &i, NULL))) {
        x->ex_flags |= EXFLAG_XKUSAGE;
        for (i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) {
            switch (OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage, i))) {
            case NID_server_auth:
                x->ex_xkusage |= XKU_SSL_SERVER;
                break;

            case NID_client_auth:
                x->ex_xkusage |= XKU_SSL_CLIENT;
                break;

            case NID_email_protect:
                x->ex_xkusage |= XKU_SMIME;
                break;

            case NID_code_sign:
                x->ex_xkusage |= XKU_CODE_SIGN;
                break;

            case NID_ms_sgc:
            case NID_ns_sgc:
                x->ex_xkusage |= XKU_SGC;
                break;

            case NID_OCSP_sign:
                x->ex_xkusage |= XKU_OCSP_SIGN;
                break;

            case NID_time_stamp:
                x->ex_xkusage |= XKU_TIMESTAMP;
                break;

            case NID_dvcs:
                x->ex_xkusage |= XKU_DVCS;
                break;

            case NID_anyExtendedKeyUsage:
                x->ex_xkusage |= XKU_ANYEKU;
                break;
            }
        }
        sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free);
    } else if (i != -1) {
        x->ex_flags |= EXFLAG_INVALID;
    }

    if ((ns = X509_get_ext_d2i(x, NID_netscape_cert_type, &i, NULL))) {
        if (ns->length > 0)
            x->ex_nscert = ns->data[0];
        else
            x->ex_nscert = 0;
        x->ex_flags |= EXFLAG_NSCERT;
        ASN1_BIT_STRING_free(ns);
    } else if (i != -1) {
        x->ex_flags |= EXFLAG_INVALID;
    }
    x->skid = X509_get_ext_d2i(x, NID_subject_key_identifier, &i, NULL);
    if (x->skid == NULL && i != -1)
        x->ex_flags |= EXFLAG_INVALID;
    x->akid = X509_get_ext_d2i(x, NID_authority_key_identifier, &i, NULL);
    if (x->akid == NULL && i != -1)
        x->ex_flags |= EXFLAG_INVALID;
    /* Does subject name match issuer ? */
    if (!X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x))) {
        x->ex_flags |= EXFLAG_SI; /* cert is self-issued */
        if (X509_check_akid(x, x->akid) == X509_V_OK /* SKID matches AKID */
                /* .. and the signature alg matches the PUBKEY alg: */
                && check_sig_alg_match(X509_get0_pubkey(x), x) == X509_V_OK)
            x->ex_flags |= EXFLAG_SS; /* indicate self-signed */
    }
    x->altname = X509_get_ext_d2i(x, NID_subject_alt_name, &i, NULL);
    if (x->altname == NULL && i != -1)
        x->ex_flags |= EXFLAG_INVALID;
    x->nc = X509_get_ext_d2i(x, NID_name_constraints, &i, NULL);
    if (x->nc == NULL && i != -1)
        x->ex_flags |= EXFLAG_INVALID;
    if (!setup_crldp(x))
        x->ex_flags |= EXFLAG_INVALID;

#ifndef OPENSSL_NO_RFC3779
    x->rfc3779_addr = X509_get_ext_d2i(x, NID_sbgp_ipAddrBlock, &i, NULL);
    if (x->rfc3779_addr == NULL && i != -1)
        x->ex_flags |= EXFLAG_INVALID;
    x->rfc3779_asid = X509_get_ext_d2i(x, NID_sbgp_autonomousSysNum, &i, NULL);
    if (x->rfc3779_asid == NULL && i != -1)
        x->ex_flags |= EXFLAG_INVALID;
#endif
    for (i = 0; i < X509_get_ext_count(x); i++) {
        ex = X509_get_ext(x, i);
        if (OBJ_obj2nid(X509_EXTENSION_get_object(ex))
            == NID_freshest_crl)
            x->ex_flags |= EXFLAG_FRESHEST;
        if (!X509_EXTENSION_get_critical(ex))
            continue;
        if (!X509_supported_extension(ex)) {
            x->ex_flags |= EXFLAG_CRITICAL;
            break;
        }
    }
    x509_init_sig_info(x);
    x->ex_flags |= EXFLAG_SET;
#ifdef tsan_st_rel
    tsan_st_rel((TSAN_QUALIFIER int *)&x->ex_cached, 1);
    /*
     * Above store triggers fast lock-free check in the beginning of the
     * function. But one has to ensure that the structure is "stable", i.e.
     * all stores are visible on all processors. Hence the release fence.
     */
#endif
    CRYPTO_THREAD_unlock(x->lock);
}

/*-
 * CA checks common to all purposes
 * return codes:
 * 0 not a CA
 * 1 is a CA
 * 2 Only possible in older versions of openSSL when basicConstraints are absent
 *   new versions will not return this value. May be a CA
 * 3 basicConstraints absent but self signed V1.
 * 4 basicConstraints absent but keyUsage present and keyCertSign asserted.
 * 5 Netscape specific CA Flags present
 */

static int check_ca(const X509 *x)
{
    /* keyUsage if present should allow cert signing */
    if (ku_reject(x, KU_KEY_CERT_SIGN))
        return 0;
    if (x->ex_flags & EXFLAG_BCONS) {
        if (x->ex_flags & EXFLAG_CA)
            return 1;
        /* If basicConstraints says not a CA then say so */
        else
            return 0;
    } else {
        /* we support V1 roots for...  uh, I don't really know why. */
        if ((x->ex_flags & V1_ROOT) == V1_ROOT)
            return 3;
        /*
         * If key usage present it must have certSign so tolerate it
         */
        else if (x->ex_flags & EXFLAG_KUSAGE)
            return 4;
        /* Older certificates could have Netscape-specific CA types */
        else if (x->ex_flags & EXFLAG_NSCERT && x->ex_nscert & NS_ANY_CA)
            return 5;
        /* can this still be regarded a CA certificate?  I doubt it */
        return 0;
    }
}

void X509_set_proxy_flag(X509 *x)
{
    x->ex_flags |= EXFLAG_PROXY;
}

void X509_set_proxy_pathlen(X509 *x, long l)
{
    x->ex_pcpathlen = l;
}

int X509_check_ca(X509 *x)
{
    x509v3_cache_extensions(x);

    return check_ca(x);
}

/* Check SSL CA: common checks for SSL client and server */
static int check_ssl_ca(const X509 *x)
{
    int ca_ret;
    ca_ret = check_ca(x);
    if (!ca_ret)
        return 0;
    /* check nsCertType if present */
    if (ca_ret != 5 || x->ex_nscert & NS_SSL_CA)
        return ca_ret;
    else
        return 0;
}

static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x,
                                    int ca)
{
    if (xku_reject(x, XKU_SSL_CLIENT))
        return 0;
    if (ca)
        return check_ssl_ca(x);
    /* We need to do digital signatures or key agreement */
    if (ku_reject(x, KU_DIGITAL_SIGNATURE | KU_KEY_AGREEMENT))
        return 0;
    /* nsCertType if present should allow SSL client use */
    if (ns_reject(x, NS_SSL_CLIENT))
        return 0;
    return 1;
}

/*
 * Key usage needed for TLS/SSL server: digital signature, encipherment or
 * key agreement. The ssl code can check this more thoroughly for individual
 * key types.
 */
#define KU_TLS \
        KU_DIGITAL_SIGNATURE|KU_KEY_ENCIPHERMENT|KU_KEY_AGREEMENT

static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x,
                                    int ca)
{
    if (xku_reject(x, XKU_SSL_SERVER | XKU_SGC))
        return 0;
    if (ca)
        return check_ssl_ca(x);

    if (ns_reject(x, NS_SSL_SERVER))
        return 0;
    if (ku_reject(x, KU_TLS))
        return 0;

    return 1;

}

static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x,
                                       int ca)
{
    int ret;
    ret = check_purpose_ssl_server(xp, x, ca);
    if (!ret || ca)
        return ret;
    /* We need to encipher or Netscape complains */
    if (ku_reject(x, KU_KEY_ENCIPHERMENT))
        return 0;
    return ret;
}

/* common S/MIME checks */
static int purpose_smime(const X509 *x, int ca)
{
    if (xku_reject(x, XKU_SMIME))
        return 0;
    if (ca) {
        int ca_ret;
        ca_ret = check_ca(x);
        if (!ca_ret)
            return 0;
        /* check nsCertType if present */
        if (ca_ret != 5 || x->ex_nscert & NS_SMIME_CA)
            return ca_ret;
        else
            return 0;
    }
    if (x->ex_flags & EXFLAG_NSCERT) {
        if (x->ex_nscert & NS_SMIME)
            return 1;
        /* Workaround for some buggy certificates */
        if (x->ex_nscert & NS_SSL_CLIENT)
            return 2;
        return 0;
    }
    return 1;
}

static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x,
                                    int ca)
{
    int ret;
    ret = purpose_smime(x, ca);
    if (!ret || ca)
        return ret;
    if (ku_reject(x, KU_DIGITAL_SIGNATURE | KU_NON_REPUDIATION))
        return 0;
    return ret;
}

static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x,
                                       int ca)
{
    int ret;
    ret = purpose_smime(x, ca);
    if (!ret || ca)
        return ret;
    if (ku_reject(x, KU_KEY_ENCIPHERMENT))
        return 0;
    return ret;
}

static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x,
                                  int ca)
{
    if (ca) {
        int ca_ret;
        if ((ca_ret = check_ca(x)) != 2)
            return ca_ret;
        else
            return 0;
    }
    if (ku_reject(x, KU_CRL_SIGN))
        return 0;
    return 1;
}

/*
 * OCSP helper: this is *not* a full OCSP check. It just checks that each CA
 * is valid. Additional checks must be made on the chain.
 */

static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca)
{
    /*
     * Must be a valid CA.  Should we really support the "I don't know" value
     * (2)?
     */
    if (ca)
        return check_ca(x);
    /* leaf certificate is checked in OCSP_verify() */
    return 1;
}

static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x,
                                        int ca)
{
    int i_ext;

    /* If ca is true we must return if this is a valid CA certificate. */
    if (ca)
        return check_ca(x);

    /*
     * Check the optional key usage field:
     * if Key Usage is present, it must be one of digitalSignature
     * and/or nonRepudiation (other values are not consistent and shall
     * be rejected).
     */
    if ((x->ex_flags & EXFLAG_KUSAGE)
        && ((x->ex_kusage & ~(KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE)) ||
            !(x->ex_kusage & (KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE))))
        return 0;

    /* Only time stamp key usage is permitted and it's required. */
    if (!(x->ex_flags & EXFLAG_XKUSAGE) || x->ex_xkusage != XKU_TIMESTAMP)
        return 0;

    /* Extended Key Usage MUST be critical */
    i_ext = X509_get_ext_by_NID(x, NID_ext_key_usage, -1);
    if (i_ext >= 0) {
        X509_EXTENSION *ext = X509_get_ext((X509 *)x, i_ext);
        if (!X509_EXTENSION_get_critical(ext))
            return 0;
    }

    return 1;
}

static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca)
{
    return 1;
}

/*-
 * Check if certificate I<issuer> is allowed to issue certificate I<subject>
 * according to the B<keyUsage> field of I<issuer> if present
 * depending on any proxyCertInfo extension of I<subject>.
 * Returns 0 for OK, or positive for reason for rejection
 * where reason codes match those for X509_verify_cert().
 */
int x509_signing_allowed(const X509 *issuer, const X509 *subject)
{
    if (subject->ex_flags & EXFLAG_PROXY) {
        if (ku_reject(issuer, KU_DIGITAL_SIGNATURE))
            return X509_V_ERR_KEYUSAGE_NO_DIGITAL_SIGNATURE;
    } else if (ku_reject(issuer, KU_KEY_CERT_SIGN))
        return X509_V_ERR_KEYUSAGE_NO_CERTSIGN;
    return X509_V_OK;
}

/*-
 * Various checks to see if one certificate issued the second.
 * This can be used to prune a set of possible issuer certificates
 * which have been looked up using some simple method such as by
 * subject name.
 * These are:
 * 1. Check issuer_name(subject) == subject_name(issuer)
 * 2. If akid(subject) exists check it matches issuer
 * 3. Check that issuer public key algorithm matches subject signature algorithm
 * 4. If key_usage(issuer) exists check it supports certificate signing
 * returns 0 for OK, positive for reason for mismatch, reasons match
 * codes for X509_verify_cert()
 */

int X509_check_issued(X509 *issuer, X509 *subject)
{
    int ret;

    if ((ret = x509_likely_issued(issuer, subject)) != X509_V_OK)
        return ret;
    return x509_signing_allowed(issuer, subject);
}

/* do the checks 1., 2., and 3. as described above for X509_check_issued() */
int x509_likely_issued(X509 *issuer, X509 *subject)
{
    if (X509_NAME_cmp(X509_get_subject_name(issuer),
                      X509_get_issuer_name(subject)))
        return X509_V_ERR_SUBJECT_ISSUER_MISMATCH;

    x509v3_cache_extensions(issuer);
    if (issuer->ex_flags & EXFLAG_INVALID)
        return X509_V_ERR_UNSPECIFIED;
    x509v3_cache_extensions(subject);
    if (subject->ex_flags & EXFLAG_INVALID)
        return X509_V_ERR_UNSPECIFIED;

    if (subject->akid) {
        int ret = X509_check_akid(issuer, subject->akid);
        if (ret != X509_V_OK)
            return ret;
    }

    /* check if the subject signature alg matches the issuer's PUBKEY alg */
    return check_sig_alg_match(X509_get0_pubkey(issuer), subject);
}

int X509_check_akid(X509 *issuer, AUTHORITY_KEYID *akid)
{

    if (!akid)
        return X509_V_OK;

    /* Check key ids (if present) */
    if (akid->keyid && issuer->skid &&
        ASN1_OCTET_STRING_cmp(akid->keyid, issuer->skid))
        return X509_V_ERR_AKID_SKID_MISMATCH;
    /* Check serial number */
    if (akid->serial &&
        ASN1_INTEGER_cmp(X509_get_serialNumber(issuer), akid->serial))
        return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH;
    /* Check issuer name */
    if (akid->issuer) {
        /*
         * Ugh, for some peculiar reason AKID includes SEQUENCE OF
         * GeneralName. So look for a DirName. There may be more than one but
         * we only take any notice of the first.
         */
        GENERAL_NAMES *gens;
        GENERAL_NAME *gen;
        X509_NAME *nm = NULL;
        int i;
        gens = akid->issuer;
        for (i = 0; i < sk_GENERAL_NAME_num(gens); i++) {
            gen = sk_GENERAL_NAME_value(gens, i);
            if (gen->type == GEN_DIRNAME) {
                nm = gen->d.dirn;
                break;
            }
        }
        if (nm && X509_NAME_cmp(nm, X509_get_issuer_name(issuer)))
            return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH;
    }
    return X509_V_OK;
}

uint32_t X509_get_extension_flags(X509 *x)
{
    /* Call for side-effect of computing hash and caching extensions */
    X509_check_purpose(x, -1, -1);
    return x->ex_flags;
}

uint32_t X509_get_key_usage(X509 *x)
{
    /* Call for side-effect of computing hash and caching extensions */
    if (X509_check_purpose(x, -1, -1) != 1)
        return 0;
    if (x->ex_flags & EXFLAG_KUSAGE)
        return x->ex_kusage;
    return UINT32_MAX;
}

uint32_t X509_get_extended_key_usage(X509 *x)
{
    /* Call for side-effect of computing hash and caching extensions */
    if (X509_check_purpose(x, -1, -1) != 1)
        return 0;
    if (x->ex_flags & EXFLAG_XKUSAGE)
        return x->ex_xkusage;
    return UINT32_MAX;
}

const ASN1_OCTET_STRING *X509_get0_subject_key_id(X509 *x)
{
    /* Call for side-effect of computing hash and caching extensions */
    if (X509_check_purpose(x, -1, -1) != 1)
        return NULL;
    return x->skid;
}

const ASN1_OCTET_STRING *X509_get0_authority_key_id(X509 *x)
{
    /* Call for side-effect of computing hash and caching extensions */
    if (X509_check_purpose(x, -1, -1) != 1)
        return NULL;
    return (x->akid != NULL ? x->akid->keyid : NULL);
}

const GENERAL_NAMES *X509_get0_authority_issuer(X509 *x)
{
    /* Call for side-effect of computing hash and caching extensions */
    if (X509_check_purpose(x, -1, -1) != 1)
        return NULL;
    return (x->akid != NULL ? x->akid->issuer : NULL);
}

const ASN1_INTEGER *X509_get0_authority_serial(X509 *x)
{
    /* Call for side-effect of computing hash and caching extensions */
    if (X509_check_purpose(x, -1, -1) != 1)
        return NULL;
    return (x->akid != NULL ? x->akid->serial : NULL);
}

long X509_get_pathlen(X509 *x)
{
    /* Called for side effect of caching extensions */
    if (X509_check_purpose(x, -1, -1) != 1
            || (x->ex_flags & EXFLAG_BCONS) == 0)
        return -1;
    return x->ex_pathlen;
}

long X509_get_proxy_pathlen(X509 *x)
{
    /* Called for side effect of caching extensions */
    if (X509_check_purpose(x, -1, -1) != 1
            || (x->ex_flags & EXFLAG_PROXY) == 0)
        return -1;
    return x->ex_pcpathlen;
}