1 /* v3_purp.c */
2 /*
3 * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL project
4 * 2001.
5 */
6 /* ====================================================================
7 * Copyright (c) 1999-2004 The OpenSSL Project. All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 *
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 *
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in
18 * the documentation and/or other materials provided with the
19 * distribution.
20 *
21 * 3. All advertising materials mentioning features or use of this
22 * software must display the following acknowledgment:
23 * "This product includes software developed by the OpenSSL Project
24 * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
25 *
26 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
27 * endorse or promote products derived from this software without
28 * prior written permission. For written permission, please contact
29 * licensing@OpenSSL.org.
30 *
31 * 5. Products derived from this software may not be called "OpenSSL"
32 * nor may "OpenSSL" appear in their names without prior written
33 * permission of the OpenSSL Project.
34 *
35 * 6. Redistributions of any form whatsoever must retain the following
36 * acknowledgment:
37 * "This product includes software developed by the OpenSSL Project
38 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
39 *
40 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
41 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
43 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
44 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
45 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
46 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
47 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
49 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
50 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
51 * OF THE POSSIBILITY OF SUCH DAMAGE.
52 * ====================================================================
53 *
54 * This product includes cryptographic software written by Eric Young
55 * (eay@cryptsoft.com). This product includes software written by Tim
56 * Hudson (tjh@cryptsoft.com).
57 *
58 */
59
60 #include <stdio.h>
61 #include "cryptlib.h"
62 #include <openssl/x509v3.h>
63 #include <openssl/x509_vfy.h>
64
65 static void x509v3_cache_extensions(X509 *x);
66
67 static int check_ssl_ca(const X509 *x);
68 static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x,
69 int ca);
70 static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x,
71 int ca);
72 static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x,
73 int ca);
74 static int purpose_smime(const X509 *x, int ca);
75 static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x,
76 int ca);
77 static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x,
78 int ca);
79 static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x,
80 int ca);
81 static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x,
82 int ca);
83 static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca);
84 static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca);
85
86 static int xp_cmp(const X509_PURPOSE *const *a, const X509_PURPOSE *const *b);
87 static void xptable_free(X509_PURPOSE *p);
88
89 static X509_PURPOSE xstandard[] = {
90 {X509_PURPOSE_SSL_CLIENT, X509_TRUST_SSL_CLIENT, 0,
91 check_purpose_ssl_client, "SSL client", "sslclient", NULL},
92 {X509_PURPOSE_SSL_SERVER, X509_TRUST_SSL_SERVER, 0,
93 check_purpose_ssl_server, "SSL server", "sslserver", NULL},
94 {X509_PURPOSE_NS_SSL_SERVER, X509_TRUST_SSL_SERVER, 0,
95 check_purpose_ns_ssl_server, "Netscape SSL server", "nssslserver", NULL},
96 {X509_PURPOSE_SMIME_SIGN, X509_TRUST_EMAIL, 0, check_purpose_smime_sign,
97 "S/MIME signing", "smimesign", NULL},
98 {X509_PURPOSE_SMIME_ENCRYPT, X509_TRUST_EMAIL, 0,
99 check_purpose_smime_encrypt, "S/MIME encryption", "smimeencrypt", NULL},
100 {X509_PURPOSE_CRL_SIGN, X509_TRUST_COMPAT, 0, check_purpose_crl_sign,
101 "CRL signing", "crlsign", NULL},
102 {X509_PURPOSE_ANY, X509_TRUST_DEFAULT, 0, no_check, "Any Purpose", "any",
103 NULL},
104 {X509_PURPOSE_OCSP_HELPER, X509_TRUST_COMPAT, 0, ocsp_helper,
105 "OCSP helper", "ocsphelper", NULL},
106 {X509_PURPOSE_TIMESTAMP_SIGN, X509_TRUST_TSA, 0,
107 check_purpose_timestamp_sign, "Time Stamp signing", "timestampsign",
108 NULL},
109 };
110
111 #define X509_PURPOSE_COUNT (sizeof(xstandard)/sizeof(X509_PURPOSE))
112
113 IMPLEMENT_STACK_OF(X509_PURPOSE)
114
115 static STACK_OF(X509_PURPOSE) *xptable = NULL;
116
xp_cmp(const X509_PURPOSE * const * a,const X509_PURPOSE * const * b)117 static int xp_cmp(const X509_PURPOSE *const *a, const X509_PURPOSE *const *b)
118 {
119 return (*a)->purpose - (*b)->purpose;
120 }
121
122 /*
123 * As much as I'd like to make X509_check_purpose use a "const" X509* I
124 * really can't because it does recalculate hashes and do other non-const
125 * things.
126 */
X509_check_purpose(X509 * x,int id,int ca)127 int X509_check_purpose(X509 *x, int id, int ca)
128 {
129 int idx;
130 const X509_PURPOSE *pt;
131 if (!(x->ex_flags & EXFLAG_SET)) {
132 CRYPTO_w_lock(CRYPTO_LOCK_X509);
133 x509v3_cache_extensions(x);
134 CRYPTO_w_unlock(CRYPTO_LOCK_X509);
135 }
136 if (id == -1)
137 return 1;
138 idx = X509_PURPOSE_get_by_id(id);
139 if (idx == -1)
140 return -1;
141 pt = X509_PURPOSE_get0(idx);
142 return pt->check_purpose(pt, x, ca);
143 }
144
X509_PURPOSE_set(int * p,int purpose)145 int X509_PURPOSE_set(int *p, int purpose)
146 {
147 if (X509_PURPOSE_get_by_id(purpose) == -1) {
148 X509V3err(X509V3_F_X509_PURPOSE_SET, X509V3_R_INVALID_PURPOSE);
149 return 0;
150 }
151 *p = purpose;
152 return 1;
153 }
154
X509_PURPOSE_get_count(void)155 int X509_PURPOSE_get_count(void)
156 {
157 if (!xptable)
158 return X509_PURPOSE_COUNT;
159 return sk_X509_PURPOSE_num(xptable) + X509_PURPOSE_COUNT;
160 }
161
X509_PURPOSE_get0(int idx)162 X509_PURPOSE *X509_PURPOSE_get0(int idx)
163 {
164 if (idx < 0)
165 return NULL;
166 if (idx < (int)X509_PURPOSE_COUNT)
167 return xstandard + idx;
168 return sk_X509_PURPOSE_value(xptable, idx - X509_PURPOSE_COUNT);
169 }
170
X509_PURPOSE_get_by_sname(char * sname)171 int X509_PURPOSE_get_by_sname(char *sname)
172 {
173 int i;
174 X509_PURPOSE *xptmp;
175 for (i = 0; i < X509_PURPOSE_get_count(); i++) {
176 xptmp = X509_PURPOSE_get0(i);
177 if (!strcmp(xptmp->sname, sname))
178 return i;
179 }
180 return -1;
181 }
182
X509_PURPOSE_get_by_id(int purpose)183 int X509_PURPOSE_get_by_id(int purpose)
184 {
185 X509_PURPOSE tmp;
186 int idx;
187 if ((purpose >= X509_PURPOSE_MIN) && (purpose <= X509_PURPOSE_MAX))
188 return purpose - X509_PURPOSE_MIN;
189 tmp.purpose = purpose;
190 if (!xptable)
191 return -1;
192 idx = sk_X509_PURPOSE_find(xptable, &tmp);
193 if (idx == -1)
194 return -1;
195 return idx + X509_PURPOSE_COUNT;
196 }
197
X509_PURPOSE_add(int id,int trust,int flags,int (* ck)(const X509_PURPOSE *,const X509 *,int),char * name,char * sname,void * arg)198 int X509_PURPOSE_add(int id, int trust, int flags,
199 int (*ck) (const X509_PURPOSE *, const X509 *, int),
200 char *name, char *sname, void *arg)
201 {
202 int idx;
203 X509_PURPOSE *ptmp;
204 /*
205 * This is set according to what we change: application can't set it
206 */
207 flags &= ~X509_PURPOSE_DYNAMIC;
208 /* This will always be set for application modified trust entries */
209 flags |= X509_PURPOSE_DYNAMIC_NAME;
210 /* Get existing entry if any */
211 idx = X509_PURPOSE_get_by_id(id);
212 /* Need a new entry */
213 if (idx == -1) {
214 if (!(ptmp = OPENSSL_malloc(sizeof(X509_PURPOSE)))) {
215 X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE);
216 return 0;
217 }
218 ptmp->flags = X509_PURPOSE_DYNAMIC;
219 } else
220 ptmp = X509_PURPOSE_get0(idx);
221
222 /* OPENSSL_free existing name if dynamic */
223 if (ptmp->flags & X509_PURPOSE_DYNAMIC_NAME) {
224 OPENSSL_free(ptmp->name);
225 OPENSSL_free(ptmp->sname);
226 }
227 /* dup supplied name */
228 ptmp->name = BUF_strdup(name);
229 ptmp->sname = BUF_strdup(sname);
230 if (!ptmp->name || !ptmp->sname) {
231 X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE);
232 return 0;
233 }
234 /* Keep the dynamic flag of existing entry */
235 ptmp->flags &= X509_PURPOSE_DYNAMIC;
236 /* Set all other flags */
237 ptmp->flags |= flags;
238
239 ptmp->purpose = id;
240 ptmp->trust = trust;
241 ptmp->check_purpose = ck;
242 ptmp->usr_data = arg;
243
244 /* If its a new entry manage the dynamic table */
245 if (idx == -1) {
246 if (!xptable && !(xptable = sk_X509_PURPOSE_new(xp_cmp))) {
247 X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE);
248 return 0;
249 }
250 if (!sk_X509_PURPOSE_push(xptable, ptmp)) {
251 X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE);
252 return 0;
253 }
254 }
255 return 1;
256 }
257
xptable_free(X509_PURPOSE * p)258 static void xptable_free(X509_PURPOSE *p)
259 {
260 if (!p)
261 return;
262 if (p->flags & X509_PURPOSE_DYNAMIC) {
263 if (p->flags & X509_PURPOSE_DYNAMIC_NAME) {
264 OPENSSL_free(p->name);
265 OPENSSL_free(p->sname);
266 }
267 OPENSSL_free(p);
268 }
269 }
270
X509_PURPOSE_cleanup(void)271 void X509_PURPOSE_cleanup(void)
272 {
273 unsigned int i;
274 sk_X509_PURPOSE_pop_free(xptable, xptable_free);
275 for (i = 0; i < X509_PURPOSE_COUNT; i++)
276 xptable_free(xstandard + i);
277 xptable = NULL;
278 }
279
X509_PURPOSE_get_id(X509_PURPOSE * xp)280 int X509_PURPOSE_get_id(X509_PURPOSE *xp)
281 {
282 return xp->purpose;
283 }
284
X509_PURPOSE_get0_name(X509_PURPOSE * xp)285 char *X509_PURPOSE_get0_name(X509_PURPOSE *xp)
286 {
287 return xp->name;
288 }
289
X509_PURPOSE_get0_sname(X509_PURPOSE * xp)290 char *X509_PURPOSE_get0_sname(X509_PURPOSE *xp)
291 {
292 return xp->sname;
293 }
294
X509_PURPOSE_get_trust(X509_PURPOSE * xp)295 int X509_PURPOSE_get_trust(X509_PURPOSE *xp)
296 {
297 return xp->trust;
298 }
299
nid_cmp(const int * a,const int * b)300 static int nid_cmp(const int *a, const int *b)
301 {
302 return *a - *b;
303 }
304
305 DECLARE_OBJ_BSEARCH_CMP_FN(int, int, nid);
306 IMPLEMENT_OBJ_BSEARCH_CMP_FN(int, int, nid);
307
X509_supported_extension(X509_EXTENSION * ex)308 int X509_supported_extension(X509_EXTENSION *ex)
309 {
310 /*
311 * This table is a list of the NIDs of supported extensions: that is
312 * those which are used by the verify process. If an extension is
313 * critical and doesn't appear in this list then the verify process will
314 * normally reject the certificate. The list must be kept in numerical
315 * order because it will be searched using bsearch.
316 */
317
318 static const int supported_nids[] = {
319 NID_netscape_cert_type, /* 71 */
320 NID_key_usage, /* 83 */
321 NID_subject_alt_name, /* 85 */
322 NID_basic_constraints, /* 87 */
323 NID_certificate_policies, /* 89 */
324 NID_ext_key_usage, /* 126 */
325 #ifndef OPENSSL_NO_RFC3779
326 NID_sbgp_ipAddrBlock, /* 290 */
327 NID_sbgp_autonomousSysNum, /* 291 */
328 #endif
329 NID_policy_constraints, /* 401 */
330 NID_proxyCertInfo, /* 663 */
331 NID_name_constraints, /* 666 */
332 NID_policy_mappings, /* 747 */
333 NID_inhibit_any_policy /* 748 */
334 };
335
336 int ex_nid = OBJ_obj2nid(X509_EXTENSION_get_object(ex));
337
338 if (ex_nid == NID_undef)
339 return 0;
340
341 if (OBJ_bsearch_nid(&ex_nid, supported_nids,
342 sizeof(supported_nids) / sizeof(int)))
343 return 1;
344 return 0;
345 }
346
setup_dp(X509 * x,DIST_POINT * dp)347 static void setup_dp(X509 *x, DIST_POINT *dp)
348 {
349 X509_NAME *iname = NULL;
350 int i;
351 if (dp->reasons) {
352 if (dp->reasons->length > 0)
353 dp->dp_reasons = dp->reasons->data[0];
354 if (dp->reasons->length > 1)
355 dp->dp_reasons |= (dp->reasons->data[1] << 8);
356 dp->dp_reasons &= CRLDP_ALL_REASONS;
357 } else
358 dp->dp_reasons = CRLDP_ALL_REASONS;
359 if (!dp->distpoint || (dp->distpoint->type != 1))
360 return;
361 for (i = 0; i < sk_GENERAL_NAME_num(dp->CRLissuer); i++) {
362 GENERAL_NAME *gen = sk_GENERAL_NAME_value(dp->CRLissuer, i);
363 if (gen->type == GEN_DIRNAME) {
364 iname = gen->d.directoryName;
365 break;
366 }
367 }
368 if (!iname)
369 iname = X509_get_issuer_name(x);
370
371 DIST_POINT_set_dpname(dp->distpoint, iname);
372
373 }
374
setup_crldp(X509 * x)375 static void setup_crldp(X509 *x)
376 {
377 int i;
378 x->crldp = X509_get_ext_d2i(x, NID_crl_distribution_points, NULL, NULL);
379 for (i = 0; i < sk_DIST_POINT_num(x->crldp); i++)
380 setup_dp(x, sk_DIST_POINT_value(x->crldp, i));
381 }
382
x509v3_cache_extensions(X509 * x)383 static void x509v3_cache_extensions(X509 *x)
384 {
385 BASIC_CONSTRAINTS *bs;
386 PROXY_CERT_INFO_EXTENSION *pci;
387 ASN1_BIT_STRING *usage;
388 ASN1_BIT_STRING *ns;
389 EXTENDED_KEY_USAGE *extusage;
390 X509_EXTENSION *ex;
391
392 int i;
393 if (x->ex_flags & EXFLAG_SET)
394 return;
395 #ifndef OPENSSL_NO_SHA
396 X509_digest(x, EVP_sha1(), x->sha1_hash, NULL);
397 #endif
398 /* Does subject name match issuer ? */
399 if (!X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x)))
400 x->ex_flags |= EXFLAG_SI;
401 /* V1 should mean no extensions ... */
402 if (!X509_get_version(x))
403 x->ex_flags |= EXFLAG_V1;
404 /* Handle basic constraints */
405 if ((bs = X509_get_ext_d2i(x, NID_basic_constraints, NULL, NULL))) {
406 if (bs->ca)
407 x->ex_flags |= EXFLAG_CA;
408 if (bs->pathlen) {
409 if ((bs->pathlen->type == V_ASN1_NEG_INTEGER)
410 || !bs->ca) {
411 x->ex_flags |= EXFLAG_INVALID;
412 x->ex_pathlen = 0;
413 } else
414 x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen);
415 } else
416 x->ex_pathlen = -1;
417 BASIC_CONSTRAINTS_free(bs);
418 x->ex_flags |= EXFLAG_BCONS;
419 }
420 /* Handle proxy certificates */
421 if ((pci = X509_get_ext_d2i(x, NID_proxyCertInfo, NULL, NULL))) {
422 if (x->ex_flags & EXFLAG_CA
423 || X509_get_ext_by_NID(x, NID_subject_alt_name, -1) >= 0
424 || X509_get_ext_by_NID(x, NID_issuer_alt_name, -1) >= 0) {
425 x->ex_flags |= EXFLAG_INVALID;
426 }
427 if (pci->pcPathLengthConstraint) {
428 x->ex_pcpathlen = ASN1_INTEGER_get(pci->pcPathLengthConstraint);
429 } else
430 x->ex_pcpathlen = -1;
431 PROXY_CERT_INFO_EXTENSION_free(pci);
432 x->ex_flags |= EXFLAG_PROXY;
433 }
434 /* Handle key usage */
435 if ((usage = X509_get_ext_d2i(x, NID_key_usage, NULL, NULL))) {
436 if (usage->length > 0) {
437 x->ex_kusage = usage->data[0];
438 if (usage->length > 1)
439 x->ex_kusage |= usage->data[1] << 8;
440 } else
441 x->ex_kusage = 0;
442 x->ex_flags |= EXFLAG_KUSAGE;
443 ASN1_BIT_STRING_free(usage);
444 }
445 x->ex_xkusage = 0;
446 if ((extusage = X509_get_ext_d2i(x, NID_ext_key_usage, NULL, NULL))) {
447 x->ex_flags |= EXFLAG_XKUSAGE;
448 for (i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) {
449 switch (OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage, i))) {
450 case NID_server_auth:
451 x->ex_xkusage |= XKU_SSL_SERVER;
452 break;
453
454 case NID_client_auth:
455 x->ex_xkusage |= XKU_SSL_CLIENT;
456 break;
457
458 case NID_email_protect:
459 x->ex_xkusage |= XKU_SMIME;
460 break;
461
462 case NID_code_sign:
463 x->ex_xkusage |= XKU_CODE_SIGN;
464 break;
465
466 case NID_ms_sgc:
467 case NID_ns_sgc:
468 x->ex_xkusage |= XKU_SGC;
469 break;
470
471 case NID_OCSP_sign:
472 x->ex_xkusage |= XKU_OCSP_SIGN;
473 break;
474
475 case NID_time_stamp:
476 x->ex_xkusage |= XKU_TIMESTAMP;
477 break;
478
479 case NID_dvcs:
480 x->ex_xkusage |= XKU_DVCS;
481 break;
482 }
483 }
484 sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free);
485 }
486
487 if ((ns = X509_get_ext_d2i(x, NID_netscape_cert_type, NULL, NULL))) {
488 if (ns->length > 0)
489 x->ex_nscert = ns->data[0];
490 else
491 x->ex_nscert = 0;
492 x->ex_flags |= EXFLAG_NSCERT;
493 ASN1_BIT_STRING_free(ns);
494 }
495 x->skid = X509_get_ext_d2i(x, NID_subject_key_identifier, NULL, NULL);
496 x->akid = X509_get_ext_d2i(x, NID_authority_key_identifier, NULL, NULL);
497 x->altname = X509_get_ext_d2i(x, NID_subject_alt_name, NULL, NULL);
498 x->nc = X509_get_ext_d2i(x, NID_name_constraints, &i, NULL);
499 if (!x->nc && (i != -1))
500 x->ex_flags |= EXFLAG_INVALID;
501 setup_crldp(x);
502
503 #ifndef OPENSSL_NO_RFC3779
504 x->rfc3779_addr = X509_get_ext_d2i(x, NID_sbgp_ipAddrBlock, NULL, NULL);
505 x->rfc3779_asid = X509_get_ext_d2i(x, NID_sbgp_autonomousSysNum,
506 NULL, NULL);
507 #endif
508 for (i = 0; i < X509_get_ext_count(x); i++) {
509 ex = X509_get_ext(x, i);
510 if (OBJ_obj2nid(X509_EXTENSION_get_object(ex))
511 == NID_freshest_crl)
512 x->ex_flags |= EXFLAG_FRESHEST;
513 if (!X509_EXTENSION_get_critical(ex))
514 continue;
515 if (!X509_supported_extension(ex)) {
516 x->ex_flags |= EXFLAG_CRITICAL;
517 break;
518 }
519 }
520 x->ex_flags |= EXFLAG_SET;
521 }
522
523 /*-
524 * CA checks common to all purposes
525 * return codes:
526 * 0 not a CA
527 * 1 is a CA
528 * 2 basicConstraints absent so "maybe" a CA
529 * 3 basicConstraints absent but self signed V1.
530 * 4 basicConstraints absent but keyUsage present and keyCertSign asserted.
531 */
532
533 #define V1_ROOT (EXFLAG_V1|EXFLAG_SS)
534 #define ku_reject(x, usage) \
535 (((x)->ex_flags & EXFLAG_KUSAGE) && !((x)->ex_kusage & (usage)))
536 #define xku_reject(x, usage) \
537 (((x)->ex_flags & EXFLAG_XKUSAGE) && !((x)->ex_xkusage & (usage)))
538 #define ns_reject(x, usage) \
539 (((x)->ex_flags & EXFLAG_NSCERT) && !((x)->ex_nscert & (usage)))
540
check_ca(const X509 * x)541 static int check_ca(const X509 *x)
542 {
543 /* keyUsage if present should allow cert signing */
544 if (ku_reject(x, KU_KEY_CERT_SIGN))
545 return 0;
546 if (x->ex_flags & EXFLAG_BCONS) {
547 if (x->ex_flags & EXFLAG_CA)
548 return 1;
549 /* If basicConstraints says not a CA then say so */
550 else
551 return 0;
552 } else {
553 /* we support V1 roots for... uh, I don't really know why. */
554 if ((x->ex_flags & V1_ROOT) == V1_ROOT)
555 return 3;
556 /*
557 * If key usage present it must have certSign so tolerate it
558 */
559 else if (x->ex_flags & EXFLAG_KUSAGE)
560 return 4;
561 /* Older certificates could have Netscape-specific CA types */
562 else if (x->ex_flags & EXFLAG_NSCERT && x->ex_nscert & NS_ANY_CA)
563 return 5;
564 /* can this still be regarded a CA certificate? I doubt it */
565 return 0;
566 }
567 }
568
X509_check_ca(X509 * x)569 int X509_check_ca(X509 *x)
570 {
571 if (!(x->ex_flags & EXFLAG_SET)) {
572 CRYPTO_w_lock(CRYPTO_LOCK_X509);
573 x509v3_cache_extensions(x);
574 CRYPTO_w_unlock(CRYPTO_LOCK_X509);
575 }
576
577 return check_ca(x);
578 }
579
580 /* Check SSL CA: common checks for SSL client and server */
check_ssl_ca(const X509 * x)581 static int check_ssl_ca(const X509 *x)
582 {
583 int ca_ret;
584 ca_ret = check_ca(x);
585 if (!ca_ret)
586 return 0;
587 /* check nsCertType if present */
588 if (ca_ret != 5 || x->ex_nscert & NS_SSL_CA)
589 return ca_ret;
590 else
591 return 0;
592 }
593
check_purpose_ssl_client(const X509_PURPOSE * xp,const X509 * x,int ca)594 static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x,
595 int ca)
596 {
597 if (xku_reject(x, XKU_SSL_CLIENT))
598 return 0;
599 if (ca)
600 return check_ssl_ca(x);
601 /* We need to do digital signatures with it */
602 if (ku_reject(x, KU_DIGITAL_SIGNATURE))
603 return 0;
604 /* nsCertType if present should allow SSL client use */
605 if (ns_reject(x, NS_SSL_CLIENT))
606 return 0;
607 return 1;
608 }
609
check_purpose_ssl_server(const X509_PURPOSE * xp,const X509 * x,int ca)610 static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x,
611 int ca)
612 {
613 if (xku_reject(x, XKU_SSL_SERVER | XKU_SGC))
614 return 0;
615 if (ca)
616 return check_ssl_ca(x);
617
618 if (ns_reject(x, NS_SSL_SERVER))
619 return 0;
620 /* Now as for keyUsage: we'll at least need to sign OR encipher */
621 if (ku_reject(x, KU_DIGITAL_SIGNATURE | KU_KEY_ENCIPHERMENT))
622 return 0;
623
624 return 1;
625
626 }
627
check_purpose_ns_ssl_server(const X509_PURPOSE * xp,const X509 * x,int ca)628 static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x,
629 int ca)
630 {
631 int ret;
632 ret = check_purpose_ssl_server(xp, x, ca);
633 if (!ret || ca)
634 return ret;
635 /* We need to encipher or Netscape complains */
636 if (ku_reject(x, KU_KEY_ENCIPHERMENT))
637 return 0;
638 return ret;
639 }
640
641 /* common S/MIME checks */
purpose_smime(const X509 * x,int ca)642 static int purpose_smime(const X509 *x, int ca)
643 {
644 if (xku_reject(x, XKU_SMIME))
645 return 0;
646 if (ca) {
647 int ca_ret;
648 ca_ret = check_ca(x);
649 if (!ca_ret)
650 return 0;
651 /* check nsCertType if present */
652 if (ca_ret != 5 || x->ex_nscert & NS_SMIME_CA)
653 return ca_ret;
654 else
655 return 0;
656 }
657 if (x->ex_flags & EXFLAG_NSCERT) {
658 if (x->ex_nscert & NS_SMIME)
659 return 1;
660 /* Workaround for some buggy certificates */
661 if (x->ex_nscert & NS_SSL_CLIENT)
662 return 2;
663 return 0;
664 }
665 return 1;
666 }
667
check_purpose_smime_sign(const X509_PURPOSE * xp,const X509 * x,int ca)668 static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x,
669 int ca)
670 {
671 int ret;
672 ret = purpose_smime(x, ca);
673 if (!ret || ca)
674 return ret;
675 if (ku_reject(x, KU_DIGITAL_SIGNATURE | KU_NON_REPUDIATION))
676 return 0;
677 return ret;
678 }
679
check_purpose_smime_encrypt(const X509_PURPOSE * xp,const X509 * x,int ca)680 static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x,
681 int ca)
682 {
683 int ret;
684 ret = purpose_smime(x, ca);
685 if (!ret || ca)
686 return ret;
687 if (ku_reject(x, KU_KEY_ENCIPHERMENT))
688 return 0;
689 return ret;
690 }
691
check_purpose_crl_sign(const X509_PURPOSE * xp,const X509 * x,int ca)692 static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x,
693 int ca)
694 {
695 if (ca) {
696 int ca_ret;
697 if ((ca_ret = check_ca(x)) != 2)
698 return ca_ret;
699 else
700 return 0;
701 }
702 if (ku_reject(x, KU_CRL_SIGN))
703 return 0;
704 return 1;
705 }
706
707 /*
708 * OCSP helper: this is *not* a full OCSP check. It just checks that each CA
709 * is valid. Additional checks must be made on the chain.
710 */
711
ocsp_helper(const X509_PURPOSE * xp,const X509 * x,int ca)712 static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca)
713 {
714 /*
715 * Must be a valid CA. Should we really support the "I don't know" value
716 * (2)?
717 */
718 if (ca)
719 return check_ca(x);
720 /* leaf certificate is checked in OCSP_verify() */
721 return 1;
722 }
723
check_purpose_timestamp_sign(const X509_PURPOSE * xp,const X509 * x,int ca)724 static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x,
725 int ca)
726 {
727 int i_ext;
728
729 /* If ca is true we must return if this is a valid CA certificate. */
730 if (ca)
731 return check_ca(x);
732
733 /*
734 * Check the optional key usage field:
735 * if Key Usage is present, it must be one of digitalSignature
736 * and/or nonRepudiation (other values are not consistent and shall
737 * be rejected).
738 */
739 if ((x->ex_flags & EXFLAG_KUSAGE)
740 && ((x->ex_kusage & ~(KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE)) ||
741 !(x->ex_kusage & (KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE))))
742 return 0;
743
744 /* Only time stamp key usage is permitted and it's required. */
745 if (!(x->ex_flags & EXFLAG_XKUSAGE) || x->ex_xkusage != XKU_TIMESTAMP)
746 return 0;
747
748 /* Extended Key Usage MUST be critical */
749 i_ext = X509_get_ext_by_NID((X509 *)x, NID_ext_key_usage, -1);
750 if (i_ext >= 0) {
751 X509_EXTENSION *ext = X509_get_ext((X509 *)x, i_ext);
752 if (!X509_EXTENSION_get_critical(ext))
753 return 0;
754 }
755
756 return 1;
757 }
758
no_check(const X509_PURPOSE * xp,const X509 * x,int ca)759 static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca)
760 {
761 return 1;
762 }
763
764 /*-
765 * Various checks to see if one certificate issued the second.
766 * This can be used to prune a set of possible issuer certificates
767 * which have been looked up using some simple method such as by
768 * subject name.
769 * These are:
770 * 1. Check issuer_name(subject) == subject_name(issuer)
771 * 2. If akid(subject) exists check it matches issuer
772 * 3. If key_usage(issuer) exists check it supports certificate signing
773 * returns 0 for OK, positive for reason for mismatch, reasons match
774 * codes for X509_verify_cert()
775 */
776
X509_check_issued(X509 * issuer,X509 * subject)777 int X509_check_issued(X509 *issuer, X509 *subject)
778 {
779 if (X509_NAME_cmp(X509_get_subject_name(issuer),
780 X509_get_issuer_name(subject)))
781 return X509_V_ERR_SUBJECT_ISSUER_MISMATCH;
782 x509v3_cache_extensions(issuer);
783 x509v3_cache_extensions(subject);
784
785 if (subject->akid) {
786 int ret = X509_check_akid(issuer, subject->akid);
787 if (ret != X509_V_OK)
788 return ret;
789 }
790
791 if (subject->ex_flags & EXFLAG_PROXY) {
792 if (ku_reject(issuer, KU_DIGITAL_SIGNATURE))
793 return X509_V_ERR_KEYUSAGE_NO_DIGITAL_SIGNATURE;
794 } else if (ku_reject(issuer, KU_KEY_CERT_SIGN))
795 return X509_V_ERR_KEYUSAGE_NO_CERTSIGN;
796 return X509_V_OK;
797 }
798
X509_check_akid(X509 * issuer,AUTHORITY_KEYID * akid)799 int X509_check_akid(X509 *issuer, AUTHORITY_KEYID *akid)
800 {
801
802 if (!akid)
803 return X509_V_OK;
804
805 /* Check key ids (if present) */
806 if (akid->keyid && issuer->skid &&
807 ASN1_OCTET_STRING_cmp(akid->keyid, issuer->skid))
808 return X509_V_ERR_AKID_SKID_MISMATCH;
809 /* Check serial number */
810 if (akid->serial &&
811 ASN1_INTEGER_cmp(X509_get_serialNumber(issuer), akid->serial))
812 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH;
813 /* Check issuer name */
814 if (akid->issuer) {
815 /*
816 * Ugh, for some peculiar reason AKID includes SEQUENCE OF
817 * GeneralName. So look for a DirName. There may be more than one but
818 * we only take any notice of the first.
819 */
820 GENERAL_NAMES *gens;
821 GENERAL_NAME *gen;
822 X509_NAME *nm = NULL;
823 int i;
824 gens = akid->issuer;
825 for (i = 0; i < sk_GENERAL_NAME_num(gens); i++) {
826 gen = sk_GENERAL_NAME_value(gens, i);
827 if (gen->type == GEN_DIRNAME) {
828 nm = gen->d.dirn;
829 break;
830 }
831 }
832 if (nm && X509_NAME_cmp(nm, X509_get_issuer_name(issuer)))
833 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH;
834 }
835 return X509_V_OK;
836 }
837