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v3_purp.c
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1 /* v3_purp.c */
2 /* Written by Dr Stephen N Henson ([email protected]) for the OpenSSL
3  * project 2001.
4  */
5 /* ====================================================================
6  * Copyright (c) 1999-2004 The OpenSSL Project. All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  *
12  * 1. Redistributions of source code must retain the above copyright
13  * notice, this list of conditions and the following disclaimer.
14  *
15  * 2. Redistributions in binary form must reproduce the above copyright
16  * notice, this list of conditions and the following disclaimer in
17  * the documentation and/or other materials provided with the
18  * distribution.
19  *
20  * 3. All advertising materials mentioning features or use of this
21  * software must display the following acknowledgment:
22  * "This product includes software developed by the OpenSSL Project
23  * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
24  *
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29  *
30  * 5. Products derived from this software may not be called "OpenSSL"
31  * nor may "OpenSSL" appear in their names without prior written
32  * permission of the OpenSSL Project.
33  *
34  * 6. Redistributions of any form whatsoever must retain the following
35  * acknowledgment:
36  * "This product includes software developed by the OpenSSL Project
37  * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
38  *
39  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
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45  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
46  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
48  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
49  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
50  * OF THE POSSIBILITY OF SUCH DAMAGE.
51  * ====================================================================
52  *
53  * This product includes cryptographic software written by Eric Young
54  * ([email protected]). This product includes software written by Tim
55  * Hudson ([email protected]).
56  *
57  */
58 
59 #include <stdio.h>
60 #include "cryptlib.h"
61 #include <openssl/x509v3.h>
62 #include <openssl/x509_vfy.h>
63 
64 static void x509v3_cache_extensions(X509 *x);
65 
66 static int check_ssl_ca(const X509 *x);
67 static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, int ca);
68 static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca);
69 static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca);
70 static int purpose_smime(const X509 *x, int ca);
71 static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, int ca);
72 static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, int ca);
73 static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, int ca);
74 static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x, int ca);
75 static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca);
76 static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca);
77 
78 static int xp_cmp(const X509_PURPOSE * const *a,
79  const X509_PURPOSE * const *b);
80 static void xptable_free(X509_PURPOSE *p);
81 
82 static X509_PURPOSE xstandard[] = {
83  {X509_PURPOSE_SSL_CLIENT, X509_TRUST_SSL_CLIENT, 0, check_purpose_ssl_client, "SSL client", "sslclient", NULL},
84  {X509_PURPOSE_SSL_SERVER, X509_TRUST_SSL_SERVER, 0, check_purpose_ssl_server, "SSL server", "sslserver", NULL},
85  {X509_PURPOSE_NS_SSL_SERVER, X509_TRUST_SSL_SERVER, 0, check_purpose_ns_ssl_server, "Netscape SSL server", "nssslserver", NULL},
86  {X509_PURPOSE_SMIME_SIGN, X509_TRUST_EMAIL, 0, check_purpose_smime_sign, "S/MIME signing", "smimesign", NULL},
87  {X509_PURPOSE_SMIME_ENCRYPT, X509_TRUST_EMAIL, 0, check_purpose_smime_encrypt, "S/MIME encryption", "smimeencrypt", NULL},
88  {X509_PURPOSE_CRL_SIGN, X509_TRUST_COMPAT, 0, check_purpose_crl_sign, "CRL signing", "crlsign", NULL},
89  {X509_PURPOSE_ANY, X509_TRUST_DEFAULT, 0, no_check, "Any Purpose", "any", NULL},
90  {X509_PURPOSE_OCSP_HELPER, X509_TRUST_COMPAT, 0, ocsp_helper, "OCSP helper", "ocsphelper", NULL},
91  {X509_PURPOSE_TIMESTAMP_SIGN, X509_TRUST_TSA, 0, check_purpose_timestamp_sign, "Time Stamp signing", "timestampsign", NULL},
92 };
93 
94 #define X509_PURPOSE_COUNT (sizeof(xstandard)/sizeof(X509_PURPOSE))
95 
97 
98 static STACK_OF(X509_PURPOSE) *xptable = NULL;
99 
100 static int xp_cmp(const X509_PURPOSE * const *a,
101  const X509_PURPOSE * const *b)
102 {
103  return (*a)->purpose - (*b)->purpose;
104 }
105 
106 /* As much as I'd like to make X509_check_purpose use a "const" X509*
107  * I really can't because it does recalculate hashes and do other non-const
108  * things. */
109 int X509_check_purpose(X509 *x, int id, int ca)
110 {
111  int idx;
112  const X509_PURPOSE *pt;
113  if(!(x->ex_flags & EXFLAG_SET)) {
115  x509v3_cache_extensions(x);
117  }
118  if(id == -1) return 1;
119  idx = X509_PURPOSE_get_by_id(id);
120  if(idx == -1) return -1;
121  pt = X509_PURPOSE_get0(idx);
122  return pt->check_purpose(pt, x, ca);
123 }
124 
125 int X509_PURPOSE_set(int *p, int purpose)
126 {
127  if(X509_PURPOSE_get_by_id(purpose) == -1) {
129  return 0;
130  }
131  *p = purpose;
132  return 1;
133 }
134 
136 {
137  if(!xptable) return X509_PURPOSE_COUNT;
138  return sk_X509_PURPOSE_num(xptable) + X509_PURPOSE_COUNT;
139 }
140 
142 {
143  if(idx < 0) return NULL;
144  if(idx < (int)X509_PURPOSE_COUNT) return xstandard + idx;
145  return sk_X509_PURPOSE_value(xptable, idx - X509_PURPOSE_COUNT);
146 }
147 
149 {
150  int i;
151  X509_PURPOSE *xptmp;
152  for(i = 0; i < X509_PURPOSE_get_count(); i++) {
153  xptmp = X509_PURPOSE_get0(i);
154  if(!strcmp(xptmp->sname, sname)) return i;
155  }
156  return -1;
157 }
158 
159 int X509_PURPOSE_get_by_id(int purpose)
160 {
161  X509_PURPOSE tmp;
162  int idx;
163  if((purpose >= X509_PURPOSE_MIN) && (purpose <= X509_PURPOSE_MAX))
164  return purpose - X509_PURPOSE_MIN;
165  tmp.purpose = purpose;
166  if(!xptable) return -1;
167  idx = sk_X509_PURPOSE_find(xptable, &tmp);
168  if(idx == -1) return -1;
169  return idx + X509_PURPOSE_COUNT;
170 }
171 
172 int X509_PURPOSE_add(int id, int trust, int flags,
173  int (*ck)(const X509_PURPOSE *, const X509 *, int),
174  char *name, char *sname, void *arg)
175 {
176  int idx;
177  X509_PURPOSE *ptmp;
178  /* This is set according to what we change: application can't set it */
179  flags &= ~X509_PURPOSE_DYNAMIC;
180  /* This will always be set for application modified trust entries */
181  flags |= X509_PURPOSE_DYNAMIC_NAME;
182  /* Get existing entry if any */
183  idx = X509_PURPOSE_get_by_id(id);
184  /* Need a new entry */
185  if(idx == -1) {
186  if(!(ptmp = OPENSSL_malloc(sizeof(X509_PURPOSE)))) {
188  return 0;
189  }
190  ptmp->flags = X509_PURPOSE_DYNAMIC;
191  } else ptmp = X509_PURPOSE_get0(idx);
192 
193  /* OPENSSL_free existing name if dynamic */
194  if(ptmp->flags & X509_PURPOSE_DYNAMIC_NAME) {
195  OPENSSL_free(ptmp->name);
196  OPENSSL_free(ptmp->sname);
197  }
198  /* dup supplied name */
199  ptmp->name = BUF_strdup(name);
200  ptmp->sname = BUF_strdup(sname);
201  if(!ptmp->name || !ptmp->sname) {
203  return 0;
204  }
205  /* Keep the dynamic flag of existing entry */
206  ptmp->flags &= X509_PURPOSE_DYNAMIC;
207  /* Set all other flags */
208  ptmp->flags |= flags;
209 
210  ptmp->purpose = id;
211  ptmp->trust = trust;
212  ptmp->check_purpose = ck;
213  ptmp->usr_data = arg;
214 
215  /* If its a new entry manage the dynamic table */
216  if(idx == -1) {
217  if(!xptable && !(xptable = sk_X509_PURPOSE_new(xp_cmp))) {
219  return 0;
220  }
221  if (!sk_X509_PURPOSE_push(xptable, ptmp)) {
223  return 0;
224  }
225  }
226  return 1;
227 }
228 
229 static void xptable_free(X509_PURPOSE *p)
230  {
231  if(!p) return;
232  if (p->flags & X509_PURPOSE_DYNAMIC)
233  {
234  if (p->flags & X509_PURPOSE_DYNAMIC_NAME) {
235  OPENSSL_free(p->name);
236  OPENSSL_free(p->sname);
237  }
238  OPENSSL_free(p);
239  }
240  }
241 
243 {
244  unsigned int i;
245  sk_X509_PURPOSE_pop_free(xptable, xptable_free);
246  for(i = 0; i < X509_PURPOSE_COUNT; i++) xptable_free(xstandard + i);
247  xptable = NULL;
248 }
249 
251 {
252  return xp->purpose;
253 }
254 
256 {
257  return xp->name;
258 }
259 
261 {
262  return xp->sname;
263 }
264 
266 {
267  return xp->trust;
268 }
269 
270 static int nid_cmp(const int *a, const int *b)
271  {
272  return *a - *b;
273  }
274 
277 
279  {
280  /* This table is a list of the NIDs of supported extensions:
281  * that is those which are used by the verify process. If
282  * an extension is critical and doesn't appear in this list
283  * then the verify process will normally reject the certificate.
284  * The list must be kept in numerical order because it will be
285  * searched using bsearch.
286  */
287 
288  static const int supported_nids[] = {
289  NID_netscape_cert_type, /* 71 */
290  NID_key_usage, /* 83 */
291  NID_subject_alt_name, /* 85 */
292  NID_basic_constraints, /* 87 */
293  NID_certificate_policies, /* 89 */
294  NID_ext_key_usage, /* 126 */
295 #ifndef OPENSSL_NO_RFC3779
296  NID_sbgp_ipAddrBlock, /* 290 */
297  NID_sbgp_autonomousSysNum, /* 291 */
298 #endif
299  NID_policy_constraints, /* 401 */
300  NID_proxyCertInfo, /* 663 */
301  NID_name_constraints, /* 666 */
302  NID_policy_mappings, /* 747 */
303  NID_inhibit_any_policy /* 748 */
304  };
305 
306  int ex_nid = OBJ_obj2nid(X509_EXTENSION_get_object(ex));
307 
308  if (ex_nid == NID_undef)
309  return 0;
310 
311  if (OBJ_bsearch_nid(&ex_nid, supported_nids,
312  sizeof(supported_nids)/sizeof(int)))
313  return 1;
314  return 0;
315  }
316 
317 static void setup_dp(X509 *x, DIST_POINT *dp)
318  {
319  X509_NAME *iname = NULL;
320  int i;
321  if (dp->reasons)
322  {
323  if (dp->reasons->length > 0)
324  dp->dp_reasons = dp->reasons->data[0];
325  if (dp->reasons->length > 1)
326  dp->dp_reasons |= (dp->reasons->data[1] << 8);
328  }
329  else
331  if (!dp->distpoint || (dp->distpoint->type != 1))
332  return;
333  for (i = 0; i < sk_GENERAL_NAME_num(dp->CRLissuer); i++)
334  {
336  if (gen->type == GEN_DIRNAME)
337  {
338  iname = gen->d.directoryName;
339  break;
340  }
341  }
342  if (!iname)
343  iname = X509_get_issuer_name(x);
344 
345  DIST_POINT_set_dpname(dp->distpoint, iname);
346 
347  }
348 
349 static void setup_crldp(X509 *x)
350  {
351  int i;
352  x->crldp = X509_get_ext_d2i(x, NID_crl_distribution_points, NULL, NULL);
353  for (i = 0; i < sk_DIST_POINT_num(x->crldp); i++)
354  setup_dp(x, sk_DIST_POINT_value(x->crldp, i));
355  }
356 
357 static void x509v3_cache_extensions(X509 *x)
358 {
359  BASIC_CONSTRAINTS *bs;
362  ASN1_BIT_STRING *ns;
363  EXTENDED_KEY_USAGE *extusage;
365 
366  int i;
367  if(x->ex_flags & EXFLAG_SET) return;
368 #ifndef OPENSSL_NO_SHA
369  X509_digest(x, EVP_sha1(), x->sha1_hash, NULL);
370 #endif
371  /* Does subject name match issuer ? */
373  x->ex_flags |= EXFLAG_SI;
374  /* V1 should mean no extensions ... */
375  if(!X509_get_version(x)) x->ex_flags |= EXFLAG_V1;
376  /* Handle basic constraints */
377  if((bs=X509_get_ext_d2i(x, NID_basic_constraints, NULL, NULL))) {
378  if(bs->ca) x->ex_flags |= EXFLAG_CA;
379  if(bs->pathlen) {
380  if((bs->pathlen->type == V_ASN1_NEG_INTEGER)
381  || !bs->ca) {
382  x->ex_flags |= EXFLAG_INVALID;
383  x->ex_pathlen = 0;
384  } else x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen);
385  } else x->ex_pathlen = -1;
386  BASIC_CONSTRAINTS_free(bs);
387  x->ex_flags |= EXFLAG_BCONS;
388  }
389  /* Handle proxy certificates */
390  if((pci=X509_get_ext_d2i(x, NID_proxyCertInfo, NULL, NULL))) {
391  if (x->ex_flags & EXFLAG_CA
393  || X509_get_ext_by_NID(x, NID_issuer_alt_name, 0) >= 0) {
394  x->ex_flags |= EXFLAG_INVALID;
395  }
396  if (pci->pcPathLengthConstraint) {
397  x->ex_pcpathlen =
399  } else x->ex_pcpathlen = -1;
400  PROXY_CERT_INFO_EXTENSION_free(pci);
401  x->ex_flags |= EXFLAG_PROXY;
402  }
403  /* Handle key usage */
404  if((usage=X509_get_ext_d2i(x, NID_key_usage, NULL, NULL))) {
405  if(usage->length > 0) {
406  x->ex_kusage = usage->data[0];
407  if(usage->length > 1)
408  x->ex_kusage |= usage->data[1] << 8;
409  } else x->ex_kusage = 0;
410  x->ex_flags |= EXFLAG_KUSAGE;
411  ASN1_BIT_STRING_free(usage);
412  }
413  x->ex_xkusage = 0;
414  if((extusage=X509_get_ext_d2i(x, NID_ext_key_usage, NULL, NULL))) {
415  x->ex_flags |= EXFLAG_XKUSAGE;
416  for(i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) {
417  switch(OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage,i))) {
418  case NID_server_auth:
420  break;
421 
422  case NID_client_auth:
424  break;
425 
426  case NID_email_protect:
427  x->ex_xkusage |= XKU_SMIME;
428  break;
429 
430  case NID_code_sign:
432  break;
433 
434  case NID_ms_sgc:
435  case NID_ns_sgc:
436  x->ex_xkusage |= XKU_SGC;
437  break;
438 
439  case NID_OCSP_sign:
441  break;
442 
443  case NID_time_stamp:
445  break;
446 
447  case NID_dvcs:
448  x->ex_xkusage |= XKU_DVCS;
449  break;
450  }
451  }
453  }
454 
455  if((ns=X509_get_ext_d2i(x, NID_netscape_cert_type, NULL, NULL))) {
456  if(ns->length > 0) x->ex_nscert = ns->data[0];
457  else x->ex_nscert = 0;
458  x->ex_flags |= EXFLAG_NSCERT;
459  ASN1_BIT_STRING_free(ns);
460  }
463  x->altname = X509_get_ext_d2i(x, NID_subject_alt_name, NULL, NULL);
464  x->nc = X509_get_ext_d2i(x, NID_name_constraints, &i, NULL);
465  if (!x->nc && (i != -1))
466  x->ex_flags |= EXFLAG_INVALID;
467  setup_crldp(x);
468 
469 #ifndef OPENSSL_NO_RFC3779
470  x->rfc3779_addr =X509_get_ext_d2i(x, NID_sbgp_ipAddrBlock, NULL, NULL);
472  NULL, NULL);
473 #endif
474  for (i = 0; i < X509_get_ext_count(x); i++)
475  {
476  ex = X509_get_ext(x, i);
478  continue;
480  == NID_freshest_crl)
482  if (!X509_supported_extension(ex))
483  {
485  break;
486  }
487  }
488  x->ex_flags |= EXFLAG_SET;
489 }
490 
491 /* CA checks common to all purposes
492  * return codes:
493  * 0 not a CA
494  * 1 is a CA
495  * 2 basicConstraints absent so "maybe" a CA
496  * 3 basicConstraints absent but self signed V1.
497  * 4 basicConstraints absent but keyUsage present and keyCertSign asserted.
498  */
499 
500 #define V1_ROOT (EXFLAG_V1|EXFLAG_SS)
501 #define ku_reject(x, usage) \
502  (((x)->ex_flags & EXFLAG_KUSAGE) && !((x)->ex_kusage & (usage)))
503 #define xku_reject(x, usage) \
504  (((x)->ex_flags & EXFLAG_XKUSAGE) && !((x)->ex_xkusage & (usage)))
505 #define ns_reject(x, usage) \
506  (((x)->ex_flags & EXFLAG_NSCERT) && !((x)->ex_nscert & (usage)))
507 
508 static int check_ca(const X509 *x)
509 {
510  /* keyUsage if present should allow cert signing */
511  if(ku_reject(x, KU_KEY_CERT_SIGN)) return 0;
512  if(x->ex_flags & EXFLAG_BCONS) {
513  if(x->ex_flags & EXFLAG_CA) return 1;
514  /* If basicConstraints says not a CA then say so */
515  else return 0;
516  } else {
517  /* we support V1 roots for... uh, I don't really know why. */
518  if((x->ex_flags & V1_ROOT) == V1_ROOT) return 3;
519  /* If key usage present it must have certSign so tolerate it */
520  else if (x->ex_flags & EXFLAG_KUSAGE) return 4;
521  /* Older certificates could have Netscape-specific CA types */
522  else if (x->ex_flags & EXFLAG_NSCERT
523  && x->ex_nscert & NS_ANY_CA) return 5;
524  /* can this still be regarded a CA certificate? I doubt it */
525  return 0;
526  }
527 }
528 
530 {
531  if(!(x->ex_flags & EXFLAG_SET)) {
533  x509v3_cache_extensions(x);
535  }
536 
537  return check_ca(x);
538 }
539 
540 /* Check SSL CA: common checks for SSL client and server */
541 static int check_ssl_ca(const X509 *x)
542 {
543  int ca_ret;
544  ca_ret = check_ca(x);
545  if(!ca_ret) return 0;
546  /* check nsCertType if present */
547  if(ca_ret != 5 || x->ex_nscert & NS_SSL_CA) return ca_ret;
548  else return 0;
549 }
550 
551 
552 static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, int ca)
553 {
554  if(xku_reject(x,XKU_SSL_CLIENT)) return 0;
555  if(ca) return check_ssl_ca(x);
556  /* We need to do digital signatures with it */
557  if(ku_reject(x,KU_DIGITAL_SIGNATURE)) return 0;
558  /* nsCertType if present should allow SSL client use */
559  if(ns_reject(x, NS_SSL_CLIENT)) return 0;
560  return 1;
561 }
562 
563 static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca)
564 {
565  if(xku_reject(x,XKU_SSL_SERVER|XKU_SGC)) return 0;
566  if(ca) return check_ssl_ca(x);
567 
568  if(ns_reject(x, NS_SSL_SERVER)) return 0;
569  /* Now as for keyUsage: we'll at least need to sign OR encipher */
571 
572  return 1;
573 
574 }
575 
576 static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca)
577 {
578  int ret;
579  ret = check_purpose_ssl_server(xp, x, ca);
580  if(!ret || ca) return ret;
581  /* We need to encipher or Netscape complains */
582  if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0;
583  return ret;
584 }
585 
586 /* common S/MIME checks */
587 static int purpose_smime(const X509 *x, int ca)
588 {
589  if(xku_reject(x,XKU_SMIME)) return 0;
590  if(ca) {
591  int ca_ret;
592  ca_ret = check_ca(x);
593  if(!ca_ret) return 0;
594  /* check nsCertType if present */
595  if(ca_ret != 5 || x->ex_nscert & NS_SMIME_CA) return ca_ret;
596  else return 0;
597  }
598  if(x->ex_flags & EXFLAG_NSCERT) {
599  if(x->ex_nscert & NS_SMIME) return 1;
600  /* Workaround for some buggy certificates */
601  if(x->ex_nscert & NS_SSL_CLIENT) return 2;
602  return 0;
603  }
604  return 1;
605 }
606 
607 static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, int ca)
608 {
609  int ret;
610  ret = purpose_smime(x, ca);
611  if(!ret || ca) return ret;
613  return ret;
614 }
615 
616 static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, int ca)
617 {
618  int ret;
619  ret = purpose_smime(x, ca);
620  if(!ret || ca) return ret;
621  if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0;
622  return ret;
623 }
624 
625 static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, int ca)
626 {
627  if(ca) {
628  int ca_ret;
629  if((ca_ret = check_ca(x)) != 2) return ca_ret;
630  else return 0;
631  }
632  if(ku_reject(x, KU_CRL_SIGN)) return 0;
633  return 1;
634 }
635 
636 /* OCSP helper: this is *not* a full OCSP check. It just checks that
637  * each CA is valid. Additional checks must be made on the chain.
638  */
639 
640 static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca)
641 {
642  /* Must be a valid CA. Should we really support the "I don't know"
643  value (2)? */
644  if(ca) return check_ca(x);
645  /* leaf certificate is checked in OCSP_verify() */
646  return 1;
647 }
648 
649 static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x,
650  int ca)
651 {
652  int i_ext;
653 
654  /* If ca is true we must return if this is a valid CA certificate. */
655  if (ca) return check_ca(x);
656 
657  /*
658  * Check the optional key usage field:
659  * if Key Usage is present, it must be one of digitalSignature
660  * and/or nonRepudiation (other values are not consistent and shall
661  * be rejected).
662  */
663  if ((x->ex_flags & EXFLAG_KUSAGE)
666  return 0;
667 
668  /* Only time stamp key usage is permitted and it's required. */
669  if (!(x->ex_flags & EXFLAG_XKUSAGE) || x->ex_xkusage != XKU_TIMESTAMP)
670  return 0;
671 
672  /* Extended Key Usage MUST be critical */
673  i_ext = X509_get_ext_by_NID((X509 *) x, NID_ext_key_usage, 0);
674  if (i_ext >= 0)
675  {
676  X509_EXTENSION *ext = X509_get_ext((X509 *) x, i_ext);
677  if (!X509_EXTENSION_get_critical(ext))
678  return 0;
679  }
680 
681  return 1;
682 }
683 
684 static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca)
685 {
686  return 1;
687 }
688 
689 /* Various checks to see if one certificate issued the second.
690  * This can be used to prune a set of possible issuer certificates
691  * which have been looked up using some simple method such as by
692  * subject name.
693  * These are:
694  * 1. Check issuer_name(subject) == subject_name(issuer)
695  * 2. If akid(subject) exists check it matches issuer
696  * 3. If key_usage(issuer) exists check it supports certificate signing
697  * returns 0 for OK, positive for reason for mismatch, reasons match
698  * codes for X509_verify_cert()
699  */
700 
701 int X509_check_issued(X509 *issuer, X509 *subject)
702 {
704  X509_get_issuer_name(subject)))
706  x509v3_cache_extensions(issuer);
707  x509v3_cache_extensions(subject);
708 
709  if(subject->akid)
710  {
711  int ret = X509_check_akid(issuer, subject->akid);
712  if (ret != X509_V_OK)
713  return ret;
714  }
715 
716  if(subject->ex_flags & EXFLAG_PROXY)
717  {
718  if(ku_reject(issuer, KU_DIGITAL_SIGNATURE))
720  }
721  else if(ku_reject(issuer, KU_KEY_CERT_SIGN))
723  return X509_V_OK;
724 }
725 
727  {
728 
729  if(!akid)
730  return X509_V_OK;
731 
732  /* Check key ids (if present) */
733  if(akid->keyid && issuer->skid &&
734  ASN1_OCTET_STRING_cmp(akid->keyid, issuer->skid) )
736  /* Check serial number */
737  if(akid->serial &&
740  /* Check issuer name */
741  if(akid->issuer)
742  {
743  /* Ugh, for some peculiar reason AKID includes
744  * SEQUENCE OF GeneralName. So look for a DirName.
745  * There may be more than one but we only take any
746  * notice of the first.
747  */
748  GENERAL_NAMES *gens;
749  GENERAL_NAME *gen;
750  X509_NAME *nm = NULL;
751  int i;
752  gens = akid->issuer;
753  for(i = 0; i < sk_GENERAL_NAME_num(gens); i++)
754  {
755  gen = sk_GENERAL_NAME_value(gens, i);
756  if(gen->type == GEN_DIRNAME)
757  {
758  nm = gen->d.dirn;
759  break;
760  }
761  }
762  if(nm && X509_NAME_cmp(nm, X509_get_issuer_name(issuer)))
764  }
765  return X509_V_OK;
766  }
767