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 #include <stdio.h>
59
60 #include <string.h>
61
62 #include <openssl/buf.h>
63 #include <openssl/err.h>
64 #include <openssl/digest.h>
65 #include <openssl/mem.h>
66 #include <openssl/obj.h>
67 #include <openssl/thread.h>
68 #include <openssl/x509_vfy.h>
69 #include <openssl/x509v3.h>
70
71 #include "../internal.h"
72
73 #define V1_ROOT (EXFLAG_V1|EXFLAG_SS)
74 #define ku_reject(x, usage) \
75 (((x)->ex_flags & EXFLAG_KUSAGE) && !((x)->ex_kusage & (usage)))
76 #define xku_reject(x, usage) \
77 (((x)->ex_flags & EXFLAG_XKUSAGE) && !((x)->ex_xkusage & (usage)))
78 #define ns_reject(x, usage) \
79 (((x)->ex_flags & EXFLAG_NSCERT) && !((x)->ex_nscert & (usage)))
80
81 static void x509v3_cache_extensions(X509 *x);
82
83 static int check_ssl_ca(const X509 *x);
84 static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x,
85 int ca);
86 static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x,
87 int ca);
88 static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x,
89 int ca);
90 static int purpose_smime(const X509 *x, int ca);
91 static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x,
92 int ca);
93 static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x,
94 int ca);
95 static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x,
96 int ca);
97 static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x,
98 int ca);
99 static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca);
100 static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca);
101
102 static int xp_cmp(const X509_PURPOSE **a, const X509_PURPOSE **b);
103 static void xptable_free(X509_PURPOSE *p);
104
105 static X509_PURPOSE xstandard[] = {
106 {X509_PURPOSE_SSL_CLIENT, X509_TRUST_SSL_CLIENT, 0,
107 check_purpose_ssl_client, (char *)"SSL client", (char *)"sslclient",
108 NULL},
109 {X509_PURPOSE_SSL_SERVER, X509_TRUST_SSL_SERVER, 0,
110 check_purpose_ssl_server, (char *)"SSL server", (char *)"sslserver",
111 NULL},
112 {X509_PURPOSE_NS_SSL_SERVER, X509_TRUST_SSL_SERVER, 0,
113 check_purpose_ns_ssl_server, (char *)"Netscape SSL server",
114 (char *)"nssslserver", NULL},
115 {X509_PURPOSE_SMIME_SIGN, X509_TRUST_EMAIL, 0, check_purpose_smime_sign,
116 (char *)"S/MIME signing", (char *)"smimesign", NULL},
117 {X509_PURPOSE_SMIME_ENCRYPT, X509_TRUST_EMAIL, 0,
118 check_purpose_smime_encrypt, (char *)"S/MIME encryption",
119 (char *)"smimeencrypt", NULL},
120 {X509_PURPOSE_CRL_SIGN, X509_TRUST_COMPAT, 0, check_purpose_crl_sign,
121 (char *)"CRL signing", (char *)"crlsign", NULL},
122 {X509_PURPOSE_ANY, X509_TRUST_DEFAULT, 0, no_check, (char *)"Any Purpose",
123 (char *)"any", NULL},
124 {X509_PURPOSE_OCSP_HELPER, X509_TRUST_COMPAT, 0, ocsp_helper,
125 (char *)"OCSP helper", (char *)"ocsphelper", NULL},
126 {X509_PURPOSE_TIMESTAMP_SIGN, X509_TRUST_TSA, 0,
127 check_purpose_timestamp_sign, (char *)"Time Stamp signing",
128 (char *)"timestampsign", NULL},
129 };
130
131 #define X509_PURPOSE_COUNT (sizeof(xstandard)/sizeof(X509_PURPOSE))
132
133 static STACK_OF(X509_PURPOSE) *xptable = NULL;
134
xp_cmp(const X509_PURPOSE ** a,const X509_PURPOSE ** b)135 static int xp_cmp(const X509_PURPOSE **a, const X509_PURPOSE **b)
136 {
137 return (*a)->purpose - (*b)->purpose;
138 }
139
140 /*
141 * As much as I'd like to make X509_check_purpose use a "const" X509* I
142 * really can't because it does recalculate hashes and do other non-const
143 * things.
144 */
X509_check_purpose(X509 * x,int id,int ca)145 int X509_check_purpose(X509 *x, int id, int ca)
146 {
147 int idx;
148 const X509_PURPOSE *pt;
149 x509v3_cache_extensions(x);
150 if (id == -1)
151 return 1;
152 idx = X509_PURPOSE_get_by_id(id);
153 if (idx == -1)
154 return -1;
155 pt = X509_PURPOSE_get0(idx);
156 return pt->check_purpose(pt, x, ca);
157 }
158
X509_PURPOSE_set(int * p,int purpose)159 int X509_PURPOSE_set(int *p, int purpose)
160 {
161 if (X509_PURPOSE_get_by_id(purpose) == -1) {
162 OPENSSL_PUT_ERROR(X509V3, X509V3_R_INVALID_PURPOSE);
163 return 0;
164 }
165 *p = purpose;
166 return 1;
167 }
168
X509_PURPOSE_get_count(void)169 int X509_PURPOSE_get_count(void)
170 {
171 if (!xptable)
172 return X509_PURPOSE_COUNT;
173 return sk_X509_PURPOSE_num(xptable) + X509_PURPOSE_COUNT;
174 }
175
X509_PURPOSE_get0(int idx)176 X509_PURPOSE *X509_PURPOSE_get0(int idx)
177 {
178 if (idx < 0)
179 return NULL;
180 if (idx < (int)X509_PURPOSE_COUNT)
181 return xstandard + idx;
182 return sk_X509_PURPOSE_value(xptable, idx - X509_PURPOSE_COUNT);
183 }
184
X509_PURPOSE_get_by_sname(char * sname)185 int X509_PURPOSE_get_by_sname(char *sname)
186 {
187 int i;
188 X509_PURPOSE *xptmp;
189 for (i = 0; i < X509_PURPOSE_get_count(); i++) {
190 xptmp = X509_PURPOSE_get0(i);
191 if (!strcmp(xptmp->sname, sname))
192 return i;
193 }
194 return -1;
195 }
196
X509_PURPOSE_get_by_id(int purpose)197 int X509_PURPOSE_get_by_id(int purpose)
198 {
199 X509_PURPOSE tmp;
200 size_t idx;
201
202 if ((purpose >= X509_PURPOSE_MIN) && (purpose <= X509_PURPOSE_MAX))
203 return purpose - X509_PURPOSE_MIN;
204 tmp.purpose = purpose;
205 if (!xptable)
206 return -1;
207
208 if (!sk_X509_PURPOSE_find(xptable, &idx, &tmp))
209 return -1;
210 return idx + X509_PURPOSE_COUNT;
211 }
212
X509_PURPOSE_add(int id,int trust,int flags,int (* ck)(const X509_PURPOSE *,const X509 *,int),char * name,char * sname,void * arg)213 int X509_PURPOSE_add(int id, int trust, int flags,
214 int (*ck) (const X509_PURPOSE *, const X509 *, int),
215 char *name, char *sname, void *arg)
216 {
217 int idx;
218 X509_PURPOSE *ptmp;
219 char *name_dup, *sname_dup;
220
221 /*
222 * This is set according to what we change: application can't set it
223 */
224 flags &= ~X509_PURPOSE_DYNAMIC;
225 /* This will always be set for application modified trust entries */
226 flags |= X509_PURPOSE_DYNAMIC_NAME;
227 /* Get existing entry if any */
228 idx = X509_PURPOSE_get_by_id(id);
229 /* Need a new entry */
230 if (idx == -1) {
231 if (!(ptmp = OPENSSL_malloc(sizeof(X509_PURPOSE)))) {
232 OPENSSL_PUT_ERROR(X509V3, ERR_R_MALLOC_FAILURE);
233 return 0;
234 }
235 ptmp->flags = X509_PURPOSE_DYNAMIC;
236 } else
237 ptmp = X509_PURPOSE_get0(idx);
238
239 /* Duplicate the supplied names. */
240 name_dup = BUF_strdup(name);
241 sname_dup = BUF_strdup(sname);
242 if (name_dup == NULL || sname_dup == NULL) {
243 OPENSSL_PUT_ERROR(X509V3, ERR_R_MALLOC_FAILURE);
244 if (name_dup != NULL)
245 OPENSSL_free(name_dup);
246 if (sname_dup != NULL)
247 OPENSSL_free(sname_dup);
248 if (idx == -1)
249 OPENSSL_free(ptmp);
250 return 0;
251 }
252
253 /* OPENSSL_free existing name if dynamic */
254 if (ptmp->flags & X509_PURPOSE_DYNAMIC_NAME) {
255 OPENSSL_free(ptmp->name);
256 OPENSSL_free(ptmp->sname);
257 }
258 /* dup supplied name */
259 ptmp->name = name_dup;
260 ptmp->sname = sname_dup;
261 /* Keep the dynamic flag of existing entry */
262 ptmp->flags &= X509_PURPOSE_DYNAMIC;
263 /* Set all other flags */
264 ptmp->flags |= flags;
265
266 ptmp->purpose = id;
267 ptmp->trust = trust;
268 ptmp->check_purpose = ck;
269 ptmp->usr_data = arg;
270
271 /* If its a new entry manage the dynamic table */
272 if (idx == -1) {
273 if (!xptable && !(xptable = sk_X509_PURPOSE_new(xp_cmp))) {
274 OPENSSL_PUT_ERROR(X509V3, ERR_R_MALLOC_FAILURE);
275 xptable_free(ptmp);
276 return 0;
277 }
278 if (!sk_X509_PURPOSE_push(xptable, ptmp)) {
279 OPENSSL_PUT_ERROR(X509V3, ERR_R_MALLOC_FAILURE);
280 xptable_free(ptmp);
281 return 0;
282 }
283 }
284 return 1;
285 }
286
xptable_free(X509_PURPOSE * p)287 static void xptable_free(X509_PURPOSE *p)
288 {
289 if (!p)
290 return;
291 if (p->flags & X509_PURPOSE_DYNAMIC) {
292 if (p->flags & X509_PURPOSE_DYNAMIC_NAME) {
293 OPENSSL_free(p->name);
294 OPENSSL_free(p->sname);
295 }
296 OPENSSL_free(p);
297 }
298 }
299
X509_PURPOSE_cleanup(void)300 void X509_PURPOSE_cleanup(void)
301 {
302 unsigned int i;
303 sk_X509_PURPOSE_pop_free(xptable, xptable_free);
304 for (i = 0; i < X509_PURPOSE_COUNT; i++)
305 xptable_free(xstandard + i);
306 xptable = NULL;
307 }
308
X509_PURPOSE_get_id(X509_PURPOSE * xp)309 int X509_PURPOSE_get_id(X509_PURPOSE *xp)
310 {
311 return xp->purpose;
312 }
313
X509_PURPOSE_get0_name(X509_PURPOSE * xp)314 char *X509_PURPOSE_get0_name(X509_PURPOSE *xp)
315 {
316 return xp->name;
317 }
318
X509_PURPOSE_get0_sname(X509_PURPOSE * xp)319 char *X509_PURPOSE_get0_sname(X509_PURPOSE *xp)
320 {
321 return xp->sname;
322 }
323
X509_PURPOSE_get_trust(X509_PURPOSE * xp)324 int X509_PURPOSE_get_trust(X509_PURPOSE *xp)
325 {
326 return xp->trust;
327 }
328
nid_cmp(const void * void_a,const void * void_b)329 static int nid_cmp(const void *void_a, const void *void_b)
330 {
331 const int *a = void_a, *b = void_b;
332
333 return *a - *b;
334 }
335
X509_supported_extension(X509_EXTENSION * ex)336 int X509_supported_extension(X509_EXTENSION *ex)
337 {
338 /*
339 * This table is a list of the NIDs of supported extensions: that is
340 * those which are used by the verify process. If an extension is
341 * critical and doesn't appear in this list then the verify process will
342 * normally reject the certificate. The list must be kept in numerical
343 * order because it will be searched using bsearch.
344 */
345
346 static const int supported_nids[] = {
347 NID_netscape_cert_type, /* 71 */
348 NID_key_usage, /* 83 */
349 NID_subject_alt_name, /* 85 */
350 NID_basic_constraints, /* 87 */
351 NID_certificate_policies, /* 89 */
352 NID_ext_key_usage, /* 126 */
353 NID_policy_constraints, /* 401 */
354 NID_proxyCertInfo, /* 663 */
355 NID_name_constraints, /* 666 */
356 NID_policy_mappings, /* 747 */
357 NID_inhibit_any_policy /* 748 */
358 };
359
360 int ex_nid = OBJ_obj2nid(X509_EXTENSION_get_object(ex));
361
362 if (ex_nid == NID_undef)
363 return 0;
364
365 if (bsearch
366 (&ex_nid, supported_nids, sizeof(supported_nids) / sizeof(int),
367 sizeof(int), nid_cmp) != NULL)
368 return 1;
369 return 0;
370 }
371
setup_dp(X509 * x,DIST_POINT * dp)372 static void setup_dp(X509 *x, DIST_POINT *dp)
373 {
374 X509_NAME *iname = NULL;
375 size_t i;
376 if (dp->reasons) {
377 if (dp->reasons->length > 0)
378 dp->dp_reasons = dp->reasons->data[0];
379 if (dp->reasons->length > 1)
380 dp->dp_reasons |= (dp->reasons->data[1] << 8);
381 dp->dp_reasons &= CRLDP_ALL_REASONS;
382 } else
383 dp->dp_reasons = CRLDP_ALL_REASONS;
384 if (!dp->distpoint || (dp->distpoint->type != 1))
385 return;
386 for (i = 0; i < sk_GENERAL_NAME_num(dp->CRLissuer); i++) {
387 GENERAL_NAME *gen = sk_GENERAL_NAME_value(dp->CRLissuer, i);
388 if (gen->type == GEN_DIRNAME) {
389 iname = gen->d.directoryName;
390 break;
391 }
392 }
393 if (!iname)
394 iname = X509_get_issuer_name(x);
395
396 DIST_POINT_set_dpname(dp->distpoint, iname);
397
398 }
399
setup_crldp(X509 * x)400 static void setup_crldp(X509 *x)
401 {
402 size_t i;
403 x->crldp = X509_get_ext_d2i(x, NID_crl_distribution_points, NULL, NULL);
404 for (i = 0; i < sk_DIST_POINT_num(x->crldp); i++)
405 setup_dp(x, sk_DIST_POINT_value(x->crldp, i));
406 }
407
x509v3_cache_extensions(X509 * x)408 static void x509v3_cache_extensions(X509 *x)
409 {
410 BASIC_CONSTRAINTS *bs;
411 PROXY_CERT_INFO_EXTENSION *pci;
412 ASN1_BIT_STRING *usage;
413 ASN1_BIT_STRING *ns;
414 EXTENDED_KEY_USAGE *extusage;
415 X509_EXTENSION *ex;
416 size_t i;
417 int j;
418
419 CRYPTO_MUTEX_lock_read(&x->lock);
420 const int is_set = x->ex_flags & EXFLAG_SET;
421 CRYPTO_MUTEX_unlock_read(&x->lock);
422
423 if (is_set) {
424 return;
425 }
426
427 CRYPTO_MUTEX_lock_write(&x->lock);
428 if (x->ex_flags & EXFLAG_SET) {
429 CRYPTO_MUTEX_unlock_write(&x->lock);
430 return;
431 }
432
433 X509_digest(x, EVP_sha1(), x->sha1_hash, NULL);
434 /* V1 should mean no extensions ... */
435 if (!X509_get_version(x))
436 x->ex_flags |= EXFLAG_V1;
437 /* Handle basic constraints */
438 if ((bs = X509_get_ext_d2i(x, NID_basic_constraints, NULL, NULL))) {
439 if (bs->ca)
440 x->ex_flags |= EXFLAG_CA;
441 if (bs->pathlen) {
442 if ((bs->pathlen->type == V_ASN1_NEG_INTEGER)
443 || !bs->ca) {
444 x->ex_flags |= EXFLAG_INVALID;
445 x->ex_pathlen = 0;
446 } else
447 x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen);
448 } else
449 x->ex_pathlen = -1;
450 BASIC_CONSTRAINTS_free(bs);
451 x->ex_flags |= EXFLAG_BCONS;
452 }
453 /* Handle proxy certificates */
454 if ((pci = X509_get_ext_d2i(x, NID_proxyCertInfo, NULL, NULL))) {
455 if (x->ex_flags & EXFLAG_CA
456 || X509_get_ext_by_NID(x, NID_subject_alt_name, -1) >= 0
457 || X509_get_ext_by_NID(x, NID_issuer_alt_name, -1) >= 0) {
458 x->ex_flags |= EXFLAG_INVALID;
459 }
460 if (pci->pcPathLengthConstraint) {
461 x->ex_pcpathlen = ASN1_INTEGER_get(pci->pcPathLengthConstraint);
462 } else
463 x->ex_pcpathlen = -1;
464 PROXY_CERT_INFO_EXTENSION_free(pci);
465 x->ex_flags |= EXFLAG_PROXY;
466 }
467 /* Handle key usage */
468 if ((usage = X509_get_ext_d2i(x, NID_key_usage, NULL, NULL))) {
469 if (usage->length > 0) {
470 x->ex_kusage = usage->data[0];
471 if (usage->length > 1)
472 x->ex_kusage |= usage->data[1] << 8;
473 } else
474 x->ex_kusage = 0;
475 x->ex_flags |= EXFLAG_KUSAGE;
476 ASN1_BIT_STRING_free(usage);
477 }
478 x->ex_xkusage = 0;
479 if ((extusage = X509_get_ext_d2i(x, NID_ext_key_usage, NULL, NULL))) {
480 x->ex_flags |= EXFLAG_XKUSAGE;
481 for (i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) {
482 switch (OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage, i))) {
483 case NID_server_auth:
484 x->ex_xkusage |= XKU_SSL_SERVER;
485 break;
486
487 case NID_client_auth:
488 x->ex_xkusage |= XKU_SSL_CLIENT;
489 break;
490
491 case NID_email_protect:
492 x->ex_xkusage |= XKU_SMIME;
493 break;
494
495 case NID_code_sign:
496 x->ex_xkusage |= XKU_CODE_SIGN;
497 break;
498
499 case NID_ms_sgc:
500 case NID_ns_sgc:
501 x->ex_xkusage |= XKU_SGC;
502 break;
503
504 case NID_OCSP_sign:
505 x->ex_xkusage |= XKU_OCSP_SIGN;
506 break;
507
508 case NID_time_stamp:
509 x->ex_xkusage |= XKU_TIMESTAMP;
510 break;
511
512 case NID_dvcs:
513 x->ex_xkusage |= XKU_DVCS;
514 break;
515
516 case NID_anyExtendedKeyUsage:
517 x->ex_xkusage |= XKU_ANYEKU;
518 break;
519 }
520 }
521 sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free);
522 }
523
524 if ((ns = X509_get_ext_d2i(x, NID_netscape_cert_type, NULL, NULL))) {
525 if (ns->length > 0)
526 x->ex_nscert = ns->data[0];
527 else
528 x->ex_nscert = 0;
529 x->ex_flags |= EXFLAG_NSCERT;
530 ASN1_BIT_STRING_free(ns);
531 }
532 x->skid = X509_get_ext_d2i(x, NID_subject_key_identifier, NULL, NULL);
533 x->akid = X509_get_ext_d2i(x, NID_authority_key_identifier, NULL, NULL);
534 /* Does subject name match issuer ? */
535 if (!X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x))) {
536 x->ex_flags |= EXFLAG_SI;
537 /* If SKID matches AKID also indicate self signed */
538 if (X509_check_akid(x, x->akid) == X509_V_OK &&
539 !ku_reject(x, KU_KEY_CERT_SIGN))
540 x->ex_flags |= EXFLAG_SS;
541 }
542 x->altname = X509_get_ext_d2i(x, NID_subject_alt_name, NULL, NULL);
543 x->nc = X509_get_ext_d2i(x, NID_name_constraints, &j, NULL);
544 if (!x->nc && (j != -1))
545 x->ex_flags |= EXFLAG_INVALID;
546 setup_crldp(x);
547
548 for (j = 0; j < X509_get_ext_count(x); j++) {
549 ex = X509_get_ext(x, j);
550 if (OBJ_obj2nid(X509_EXTENSION_get_object(ex))
551 == NID_freshest_crl)
552 x->ex_flags |= EXFLAG_FRESHEST;
553 if (!X509_EXTENSION_get_critical(ex))
554 continue;
555 if (!X509_supported_extension(ex)) {
556 x->ex_flags |= EXFLAG_CRITICAL;
557 break;
558 }
559 }
560 x->ex_flags |= EXFLAG_SET;
561
562 CRYPTO_MUTEX_unlock_write(&x->lock);
563 }
564
565 /*
566 * CA checks common to all purposes return codes: 0 not a CA 1 is a CA 2
567 * basicConstraints absent so "maybe" a CA 3 basicConstraints absent but self
568 * signed V1. 4 basicConstraints absent but keyUsage present and keyCertSign
569 * asserted.
570 */
571
check_ca(const X509 * x)572 static int check_ca(const X509 *x)
573 {
574 /* keyUsage if present should allow cert signing */
575 if (ku_reject(x, KU_KEY_CERT_SIGN))
576 return 0;
577 if (x->ex_flags & EXFLAG_BCONS) {
578 if (x->ex_flags & EXFLAG_CA)
579 return 1;
580 /* If basicConstraints says not a CA then say so */
581 else
582 return 0;
583 } else {
584 /* we support V1 roots for... uh, I don't really know why. */
585 if ((x->ex_flags & V1_ROOT) == V1_ROOT)
586 return 3;
587 /*
588 * If key usage present it must have certSign so tolerate it
589 */
590 else if (x->ex_flags & EXFLAG_KUSAGE)
591 return 4;
592 /* Older certificates could have Netscape-specific CA types */
593 else if (x->ex_flags & EXFLAG_NSCERT && x->ex_nscert & NS_ANY_CA)
594 return 5;
595 /* can this still be regarded a CA certificate? I doubt it */
596 return 0;
597 }
598 }
599
X509_check_ca(X509 * x)600 int X509_check_ca(X509 *x)
601 {
602 x509v3_cache_extensions(x);
603 return check_ca(x);
604 }
605
606 /* Check SSL CA: common checks for SSL client and server */
check_ssl_ca(const X509 * x)607 static int check_ssl_ca(const X509 *x)
608 {
609 int ca_ret;
610 ca_ret = check_ca(x);
611 if (!ca_ret)
612 return 0;
613 /* check nsCertType if present */
614 if (ca_ret != 5 || x->ex_nscert & NS_SSL_CA)
615 return ca_ret;
616 else
617 return 0;
618 }
619
check_purpose_ssl_client(const X509_PURPOSE * xp,const X509 * x,int ca)620 static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x,
621 int ca)
622 {
623 if (xku_reject(x, XKU_SSL_CLIENT))
624 return 0;
625 if (ca)
626 return check_ssl_ca(x);
627 /* We need to do digital signatures or key agreement */
628 if (ku_reject(x, KU_DIGITAL_SIGNATURE | KU_KEY_AGREEMENT))
629 return 0;
630 /* nsCertType if present should allow SSL client use */
631 if (ns_reject(x, NS_SSL_CLIENT))
632 return 0;
633 return 1;
634 }
635
636 /*
637 * Key usage needed for TLS/SSL server: digital signature, encipherment or
638 * key agreement. The ssl code can check this more thoroughly for individual
639 * key types.
640 */
641 #define KU_TLS \
642 (KU_DIGITAL_SIGNATURE|KU_KEY_ENCIPHERMENT|KU_KEY_AGREEMENT)
643
check_purpose_ssl_server(const X509_PURPOSE * xp,const X509 * x,int ca)644 static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x,
645 int ca)
646 {
647 if (xku_reject(x, XKU_SSL_SERVER | XKU_SGC))
648 return 0;
649 if (ca)
650 return check_ssl_ca(x);
651
652 if (ns_reject(x, NS_SSL_SERVER))
653 return 0;
654 if (ku_reject(x, KU_TLS))
655 return 0;
656
657 return 1;
658
659 }
660
check_purpose_ns_ssl_server(const X509_PURPOSE * xp,const X509 * x,int ca)661 static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x,
662 int ca)
663 {
664 int ret;
665 ret = check_purpose_ssl_server(xp, x, ca);
666 if (!ret || ca)
667 return ret;
668 /* We need to encipher or Netscape complains */
669 if (ku_reject(x, KU_KEY_ENCIPHERMENT))
670 return 0;
671 return ret;
672 }
673
674 /* common S/MIME checks */
purpose_smime(const X509 * x,int ca)675 static int purpose_smime(const X509 *x, int ca)
676 {
677 if (xku_reject(x, XKU_SMIME))
678 return 0;
679 if (ca) {
680 int ca_ret;
681 ca_ret = check_ca(x);
682 if (!ca_ret)
683 return 0;
684 /* check nsCertType if present */
685 if (ca_ret != 5 || x->ex_nscert & NS_SMIME_CA)
686 return ca_ret;
687 else
688 return 0;
689 }
690 if (x->ex_flags & EXFLAG_NSCERT) {
691 if (x->ex_nscert & NS_SMIME)
692 return 1;
693 /* Workaround for some buggy certificates */
694 if (x->ex_nscert & NS_SSL_CLIENT)
695 return 2;
696 return 0;
697 }
698 return 1;
699 }
700
check_purpose_smime_sign(const X509_PURPOSE * xp,const X509 * x,int ca)701 static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x,
702 int ca)
703 {
704 int ret;
705 ret = purpose_smime(x, ca);
706 if (!ret || ca)
707 return ret;
708 if (ku_reject(x, KU_DIGITAL_SIGNATURE | KU_NON_REPUDIATION))
709 return 0;
710 return ret;
711 }
712
check_purpose_smime_encrypt(const X509_PURPOSE * xp,const X509 * x,int ca)713 static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x,
714 int ca)
715 {
716 int ret;
717 ret = purpose_smime(x, ca);
718 if (!ret || ca)
719 return ret;
720 if (ku_reject(x, KU_KEY_ENCIPHERMENT))
721 return 0;
722 return ret;
723 }
724
check_purpose_crl_sign(const X509_PURPOSE * xp,const X509 * x,int ca)725 static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x,
726 int ca)
727 {
728 if (ca) {
729 int ca_ret;
730 if ((ca_ret = check_ca(x)) != 2)
731 return ca_ret;
732 else
733 return 0;
734 }
735 if (ku_reject(x, KU_CRL_SIGN))
736 return 0;
737 return 1;
738 }
739
740 /*
741 * OCSP helper: this is *not* a full OCSP check. It just checks that each CA
742 * is valid. Additional checks must be made on the chain.
743 */
744
ocsp_helper(const X509_PURPOSE * xp,const X509 * x,int ca)745 static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca)
746 {
747 /*
748 * Must be a valid CA. Should we really support the "I don't know" value
749 * (2)?
750 */
751 if (ca)
752 return check_ca(x);
753 /* leaf certificate is checked in OCSP_verify() */
754 return 1;
755 }
756
check_purpose_timestamp_sign(const X509_PURPOSE * xp,const X509 * x,int ca)757 static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x,
758 int ca)
759 {
760 int i_ext;
761
762 /* If ca is true we must return if this is a valid CA certificate. */
763 if (ca)
764 return check_ca(x);
765
766 /*
767 * Check the optional key usage field:
768 * if Key Usage is present, it must be one of digitalSignature
769 * and/or nonRepudiation (other values are not consistent and shall
770 * be rejected).
771 */
772 if ((x->ex_flags & EXFLAG_KUSAGE)
773 && ((x->ex_kusage & ~(KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE)) ||
774 !(x->ex_kusage & (KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE))))
775 return 0;
776
777 /* Only time stamp key usage is permitted and it's required. */
778 if (!(x->ex_flags & EXFLAG_XKUSAGE) || x->ex_xkusage != XKU_TIMESTAMP)
779 return 0;
780
781 /* Extended Key Usage MUST be critical */
782 i_ext = X509_get_ext_by_NID((X509 *)x, NID_ext_key_usage, -1);
783 if (i_ext >= 0) {
784 X509_EXTENSION *ext = X509_get_ext((X509 *)x, i_ext);
785 if (!X509_EXTENSION_get_critical(ext))
786 return 0;
787 }
788
789 return 1;
790 }
791
no_check(const X509_PURPOSE * xp,const X509 * x,int ca)792 static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca)
793 {
794 return 1;
795 }
796
797 /*
798 * Various checks to see if one certificate issued the second. This can be
799 * used to prune a set of possible issuer certificates which have been looked
800 * up using some simple method such as by subject name. These are: 1. Check
801 * issuer_name(subject) == subject_name(issuer) 2. If akid(subject) exists
802 * check it matches issuer 3. If key_usage(issuer) exists check it supports
803 * certificate signing returns 0 for OK, positive for reason for mismatch,
804 * reasons match codes for X509_verify_cert()
805 */
806
X509_check_issued(X509 * issuer,X509 * subject)807 int X509_check_issued(X509 *issuer, X509 *subject)
808 {
809 if (X509_NAME_cmp(X509_get_subject_name(issuer),
810 X509_get_issuer_name(subject)))
811 return X509_V_ERR_SUBJECT_ISSUER_MISMATCH;
812 x509v3_cache_extensions(issuer);
813 x509v3_cache_extensions(subject);
814
815 if (subject->akid) {
816 int ret = X509_check_akid(issuer, subject->akid);
817 if (ret != X509_V_OK)
818 return ret;
819 }
820
821 if (subject->ex_flags & EXFLAG_PROXY) {
822 if (ku_reject(issuer, KU_DIGITAL_SIGNATURE))
823 return X509_V_ERR_KEYUSAGE_NO_DIGITAL_SIGNATURE;
824 } else if (ku_reject(issuer, KU_KEY_CERT_SIGN))
825 return X509_V_ERR_KEYUSAGE_NO_CERTSIGN;
826 return X509_V_OK;
827 }
828
X509_check_akid(X509 * issuer,AUTHORITY_KEYID * akid)829 int X509_check_akid(X509 *issuer, AUTHORITY_KEYID *akid)
830 {
831
832 if (!akid)
833 return X509_V_OK;
834
835 /* Check key ids (if present) */
836 if (akid->keyid && issuer->skid &&
837 ASN1_OCTET_STRING_cmp(akid->keyid, issuer->skid))
838 return X509_V_ERR_AKID_SKID_MISMATCH;
839 /* Check serial number */
840 if (akid->serial &&
841 ASN1_INTEGER_cmp(X509_get_serialNumber(issuer), akid->serial))
842 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH;
843 /* Check issuer name */
844 if (akid->issuer) {
845 /*
846 * Ugh, for some peculiar reason AKID includes SEQUENCE OF
847 * GeneralName. So look for a DirName. There may be more than one but
848 * we only take any notice of the first.
849 */
850 GENERAL_NAMES *gens;
851 GENERAL_NAME *gen;
852 X509_NAME *nm = NULL;
853 size_t i;
854 gens = akid->issuer;
855 for (i = 0; i < sk_GENERAL_NAME_num(gens); i++) {
856 gen = sk_GENERAL_NAME_value(gens, i);
857 if (gen->type == GEN_DIRNAME) {
858 nm = gen->d.dirn;
859 break;
860 }
861 }
862 if (nm && X509_NAME_cmp(nm, X509_get_issuer_name(issuer)))
863 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH;
864 }
865 return X509_V_OK;
866 }
867