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) 1999-2018 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
132 x509v3_cache_extensions(x);
133
134 /* Return if side-effect only call */
135 if (id == -1)
136 return 1;
137 idx = X509_PURPOSE_get_by_id(id);
138 if (idx == -1)
139 return -1;
140 pt = X509_PURPOSE_get0(idx);
141 return pt->check_purpose(pt, x, ca);
142 }
143
X509_PURPOSE_set(int * p,int purpose)144 int X509_PURPOSE_set(int *p, int purpose)
145 {
146 if (X509_PURPOSE_get_by_id(purpose) == -1) {
147 X509V3err(X509V3_F_X509_PURPOSE_SET, X509V3_R_INVALID_PURPOSE);
148 return 0;
149 }
150 *p = purpose;
151 return 1;
152 }
153
X509_PURPOSE_get_count(void)154 int X509_PURPOSE_get_count(void)
155 {
156 if (!xptable)
157 return X509_PURPOSE_COUNT;
158 return sk_X509_PURPOSE_num(xptable) + X509_PURPOSE_COUNT;
159 }
160
X509_PURPOSE_get0(int idx)161 X509_PURPOSE *X509_PURPOSE_get0(int idx)
162 {
163 if (idx < 0)
164 return NULL;
165 if (idx < (int)X509_PURPOSE_COUNT)
166 return xstandard + idx;
167 return sk_X509_PURPOSE_value(xptable, idx - X509_PURPOSE_COUNT);
168 }
169
X509_PURPOSE_get_by_sname(char * sname)170 int X509_PURPOSE_get_by_sname(char *sname)
171 {
172 int i;
173 X509_PURPOSE *xptmp;
174 for (i = 0; i < X509_PURPOSE_get_count(); i++) {
175 xptmp = X509_PURPOSE_get0(i);
176 if (!strcmp(xptmp->sname, sname))
177 return i;
178 }
179 return -1;
180 }
181
X509_PURPOSE_get_by_id(int purpose)182 int X509_PURPOSE_get_by_id(int purpose)
183 {
184 X509_PURPOSE tmp;
185 int idx;
186 if ((purpose >= X509_PURPOSE_MIN) && (purpose <= X509_PURPOSE_MAX))
187 return purpose - X509_PURPOSE_MIN;
188 tmp.purpose = purpose;
189 if (!xptable)
190 return -1;
191 idx = sk_X509_PURPOSE_find(xptable, &tmp);
192 if (idx == -1)
193 return -1;
194 return idx + X509_PURPOSE_COUNT;
195 }
196
X509_PURPOSE_add(int id,int trust,int flags,int (* ck)(const X509_PURPOSE *,const X509 *,int),char * name,char * sname,void * arg)197 int X509_PURPOSE_add(int id, int trust, int flags,
198 int (*ck) (const X509_PURPOSE *, const X509 *, int),
199 char *name, char *sname, void *arg)
200 {
201 int idx;
202 X509_PURPOSE *ptmp;
203 /*
204 * This is set according to what we change: application can't set it
205 */
206 flags &= ~X509_PURPOSE_DYNAMIC;
207 /* This will always be set for application modified trust entries */
208 flags |= X509_PURPOSE_DYNAMIC_NAME;
209 /* Get existing entry if any */
210 idx = X509_PURPOSE_get_by_id(id);
211 /* Need a new entry */
212 if (idx == -1) {
213 if (!(ptmp = OPENSSL_malloc(sizeof(X509_PURPOSE)))) {
214 X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE);
215 return 0;
216 }
217 ptmp->flags = X509_PURPOSE_DYNAMIC;
218 } else
219 ptmp = X509_PURPOSE_get0(idx);
220
221 /* OPENSSL_free existing name if dynamic */
222 if (ptmp->flags & X509_PURPOSE_DYNAMIC_NAME) {
223 OPENSSL_free(ptmp->name);
224 OPENSSL_free(ptmp->sname);
225 }
226 /* dup supplied name */
227 ptmp->name = BUF_strdup(name);
228 ptmp->sname = BUF_strdup(sname);
229 if (!ptmp->name || !ptmp->sname) {
230 X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE);
231 return 0;
232 }
233 /* Keep the dynamic flag of existing entry */
234 ptmp->flags &= X509_PURPOSE_DYNAMIC;
235 /* Set all other flags */
236 ptmp->flags |= flags;
237
238 ptmp->purpose = id;
239 ptmp->trust = trust;
240 ptmp->check_purpose = ck;
241 ptmp->usr_data = arg;
242
243 /* If its a new entry manage the dynamic table */
244 if (idx == -1) {
245 if (!xptable && !(xptable = sk_X509_PURPOSE_new(xp_cmp))) {
246 X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE);
247 return 0;
248 }
249 if (!sk_X509_PURPOSE_push(xptable, ptmp)) {
250 X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE);
251 return 0;
252 }
253 }
254 return 1;
255 }
256
xptable_free(X509_PURPOSE * p)257 static void xptable_free(X509_PURPOSE *p)
258 {
259 if (!p)
260 return;
261 if (p->flags & X509_PURPOSE_DYNAMIC) {
262 if (p->flags & X509_PURPOSE_DYNAMIC_NAME) {
263 OPENSSL_free(p->name);
264 OPENSSL_free(p->sname);
265 }
266 OPENSSL_free(p);
267 }
268 }
269
X509_PURPOSE_cleanup(void)270 void X509_PURPOSE_cleanup(void)
271 {
272 unsigned int i;
273 sk_X509_PURPOSE_pop_free(xptable, xptable_free);
274 for (i = 0; i < X509_PURPOSE_COUNT; i++)
275 xptable_free(xstandard + i);
276 xptable = NULL;
277 }
278
X509_PURPOSE_get_id(X509_PURPOSE * xp)279 int X509_PURPOSE_get_id(X509_PURPOSE *xp)
280 {
281 return xp->purpose;
282 }
283
X509_PURPOSE_get0_name(X509_PURPOSE * xp)284 char *X509_PURPOSE_get0_name(X509_PURPOSE *xp)
285 {
286 return xp->name;
287 }
288
X509_PURPOSE_get0_sname(X509_PURPOSE * xp)289 char *X509_PURPOSE_get0_sname(X509_PURPOSE *xp)
290 {
291 return xp->sname;
292 }
293
X509_PURPOSE_get_trust(X509_PURPOSE * xp)294 int X509_PURPOSE_get_trust(X509_PURPOSE *xp)
295 {
296 return xp->trust;
297 }
298
nid_cmp(const int * a,const int * b)299 static int nid_cmp(const int *a, const int *b)
300 {
301 return *a - *b;
302 }
303
304 DECLARE_OBJ_BSEARCH_CMP_FN(int, int, nid);
305 IMPLEMENT_OBJ_BSEARCH_CMP_FN(int, int, nid);
306
X509_supported_extension(X509_EXTENSION * ex)307 int X509_supported_extension(X509_EXTENSION *ex)
308 {
309 /*
310 * This table is a list of the NIDs of supported extensions: that is
311 * those which are used by the verify process. If an extension is
312 * critical and doesn't appear in this list then the verify process will
313 * normally reject the certificate. The list must be kept in numerical
314 * order because it will be searched using bsearch.
315 */
316
317 static const int supported_nids[] = {
318 NID_netscape_cert_type, /* 71 */
319 NID_key_usage, /* 83 */
320 NID_subject_alt_name, /* 85 */
321 NID_basic_constraints, /* 87 */
322 NID_certificate_policies, /* 89 */
323 NID_crl_distribution_points, /* 103 */
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
383 #define V1_ROOT (EXFLAG_V1|EXFLAG_SS)
384 #define ku_reject(x, usage) \
385 (((x)->ex_flags & EXFLAG_KUSAGE) && !((x)->ex_kusage & (usage)))
386 #define xku_reject(x, usage) \
387 (((x)->ex_flags & EXFLAG_XKUSAGE) && !((x)->ex_xkusage & (usage)))
388 #define ns_reject(x, usage) \
389 (((x)->ex_flags & EXFLAG_NSCERT) && !((x)->ex_nscert & (usage)))
390
x509v3_cache_extensions(X509 * x)391 static void x509v3_cache_extensions(X509 *x)
392 {
393 BASIC_CONSTRAINTS *bs;
394 PROXY_CERT_INFO_EXTENSION *pci;
395 ASN1_BIT_STRING *usage;
396 ASN1_BIT_STRING *ns;
397 EXTENDED_KEY_USAGE *extusage;
398 X509_EXTENSION *ex;
399 int i;
400
401 CRYPTO_w_lock(CRYPTO_LOCK_X509);
402 if (x->ex_flags & EXFLAG_SET) {
403 CRYPTO_w_unlock(CRYPTO_LOCK_X509);
404 return;
405 }
406
407 #ifndef OPENSSL_NO_SHA
408 X509_digest(x, EVP_sha1(), x->sha1_hash, NULL);
409 #endif
410 /* V1 should mean no extensions ... */
411 if (!X509_get_version(x))
412 x->ex_flags |= EXFLAG_V1;
413 /* Handle basic constraints */
414 if ((bs = X509_get_ext_d2i(x, NID_basic_constraints, NULL, NULL))) {
415 if (bs->ca)
416 x->ex_flags |= EXFLAG_CA;
417 if (bs->pathlen) {
418 if ((bs->pathlen->type == V_ASN1_NEG_INTEGER)
419 || !bs->ca) {
420 x->ex_flags |= EXFLAG_INVALID;
421 x->ex_pathlen = 0;
422 } else
423 x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen);
424 } else
425 x->ex_pathlen = -1;
426 BASIC_CONSTRAINTS_free(bs);
427 x->ex_flags |= EXFLAG_BCONS;
428 }
429 /* Handle proxy certificates */
430 if ((pci = X509_get_ext_d2i(x, NID_proxyCertInfo, NULL, NULL))) {
431 if (x->ex_flags & EXFLAG_CA
432 || X509_get_ext_by_NID(x, NID_subject_alt_name, -1) >= 0
433 || X509_get_ext_by_NID(x, NID_issuer_alt_name, -1) >= 0) {
434 x->ex_flags |= EXFLAG_INVALID;
435 }
436 if (pci->pcPathLengthConstraint) {
437 x->ex_pcpathlen = ASN1_INTEGER_get(pci->pcPathLengthConstraint);
438 } else
439 x->ex_pcpathlen = -1;
440 PROXY_CERT_INFO_EXTENSION_free(pci);
441 x->ex_flags |= EXFLAG_PROXY;
442 }
443 /* Handle key usage */
444 if ((usage = X509_get_ext_d2i(x, NID_key_usage, NULL, NULL))) {
445 if (usage->length > 0) {
446 x->ex_kusage = usage->data[0];
447 if (usage->length > 1)
448 x->ex_kusage |= usage->data[1] << 8;
449 } else
450 x->ex_kusage = 0;
451 x->ex_flags |= EXFLAG_KUSAGE;
452 ASN1_BIT_STRING_free(usage);
453 }
454 x->ex_xkusage = 0;
455 if ((extusage = X509_get_ext_d2i(x, NID_ext_key_usage, NULL, NULL))) {
456 x->ex_flags |= EXFLAG_XKUSAGE;
457 for (i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) {
458 switch (OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage, i))) {
459 case NID_server_auth:
460 x->ex_xkusage |= XKU_SSL_SERVER;
461 break;
462
463 case NID_client_auth:
464 x->ex_xkusage |= XKU_SSL_CLIENT;
465 break;
466
467 case NID_email_protect:
468 x->ex_xkusage |= XKU_SMIME;
469 break;
470
471 case NID_code_sign:
472 x->ex_xkusage |= XKU_CODE_SIGN;
473 break;
474
475 case NID_ms_sgc:
476 case NID_ns_sgc:
477 x->ex_xkusage |= XKU_SGC;
478 break;
479
480 case NID_OCSP_sign:
481 x->ex_xkusage |= XKU_OCSP_SIGN;
482 break;
483
484 case NID_time_stamp:
485 x->ex_xkusage |= XKU_TIMESTAMP;
486 break;
487
488 case NID_dvcs:
489 x->ex_xkusage |= XKU_DVCS;
490 break;
491
492 case NID_anyExtendedKeyUsage:
493 x->ex_xkusage |= XKU_ANYEKU;
494 break;
495 }
496 }
497 sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free);
498 }
499
500 if ((ns = X509_get_ext_d2i(x, NID_netscape_cert_type, NULL, NULL))) {
501 if (ns->length > 0)
502 x->ex_nscert = ns->data[0];
503 else
504 x->ex_nscert = 0;
505 x->ex_flags |= EXFLAG_NSCERT;
506 ASN1_BIT_STRING_free(ns);
507 }
508 x->skid = X509_get_ext_d2i(x, NID_subject_key_identifier, NULL, NULL);
509 x->akid = X509_get_ext_d2i(x, NID_authority_key_identifier, NULL, NULL);
510 /* Does subject name match issuer ? */
511 if (!X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x))) {
512 x->ex_flags |= EXFLAG_SI;
513 /* If SKID matches AKID also indicate self signed */
514 if (X509_check_akid(x, x->akid) == X509_V_OK &&
515 !ku_reject(x, KU_KEY_CERT_SIGN))
516 x->ex_flags |= EXFLAG_SS;
517 }
518 x->altname = X509_get_ext_d2i(x, NID_subject_alt_name, NULL, NULL);
519 x->nc = X509_get_ext_d2i(x, NID_name_constraints, &i, NULL);
520 if (!x->nc && (i != -1))
521 x->ex_flags |= EXFLAG_INVALID;
522 setup_crldp(x);
523
524 #ifndef OPENSSL_NO_RFC3779
525 x->rfc3779_addr = X509_get_ext_d2i(x, NID_sbgp_ipAddrBlock, NULL, NULL);
526 x->rfc3779_asid = X509_get_ext_d2i(x, NID_sbgp_autonomousSysNum,
527 NULL, NULL);
528 #endif
529 for (i = 0; i < X509_get_ext_count(x); i++) {
530 ex = X509_get_ext(x, i);
531 if (OBJ_obj2nid(X509_EXTENSION_get_object(ex))
532 == NID_freshest_crl)
533 x->ex_flags |= EXFLAG_FRESHEST;
534 if (!X509_EXTENSION_get_critical(ex))
535 continue;
536 if (!X509_supported_extension(ex)) {
537 x->ex_flags |= EXFLAG_CRITICAL;
538 break;
539 }
540 }
541 x->ex_flags |= EXFLAG_SET;
542 CRYPTO_w_unlock(CRYPTO_LOCK_X509);
543 }
544
545 /*-
546 * CA checks common to all purposes
547 * return codes:
548 * 0 not a CA
549 * 1 is a CA
550 * 2 basicConstraints absent so "maybe" a CA
551 * 3 basicConstraints absent but self signed V1.
552 * 4 basicConstraints absent but keyUsage present and keyCertSign asserted.
553 */
554
check_ca(const X509 * x)555 static int check_ca(const X509 *x)
556 {
557 /* keyUsage if present should allow cert signing */
558 if (ku_reject(x, KU_KEY_CERT_SIGN))
559 return 0;
560 if (x->ex_flags & EXFLAG_BCONS) {
561 if (x->ex_flags & EXFLAG_CA)
562 return 1;
563 /* If basicConstraints says not a CA then say so */
564 else
565 return 0;
566 } else {
567 /* we support V1 roots for... uh, I don't really know why. */
568 if ((x->ex_flags & V1_ROOT) == V1_ROOT)
569 return 3;
570 /*
571 * If key usage present it must have certSign so tolerate it
572 */
573 else if (x->ex_flags & EXFLAG_KUSAGE)
574 return 4;
575 /* Older certificates could have Netscape-specific CA types */
576 else if (x->ex_flags & EXFLAG_NSCERT && x->ex_nscert & NS_ANY_CA)
577 return 5;
578 /* can this still be regarded a CA certificate? I doubt it */
579 return 0;
580 }
581 }
582
X509_check_ca(X509 * x)583 int X509_check_ca(X509 *x)
584 {
585 x509v3_cache_extensions(x);
586
587 return check_ca(x);
588 }
589
590 /* Check SSL CA: common checks for SSL client and server */
check_ssl_ca(const X509 * x)591 static int check_ssl_ca(const X509 *x)
592 {
593 int ca_ret;
594 ca_ret = check_ca(x);
595 if (!ca_ret)
596 return 0;
597 /* check nsCertType if present */
598 if (ca_ret != 5 || x->ex_nscert & NS_SSL_CA)
599 return ca_ret;
600 else
601 return 0;
602 }
603
check_purpose_ssl_client(const X509_PURPOSE * xp,const X509 * x,int ca)604 static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x,
605 int ca)
606 {
607 if (xku_reject(x, XKU_SSL_CLIENT))
608 return 0;
609 if (ca)
610 return check_ssl_ca(x);
611 /* We need to do digital signatures or key agreement */
612 if (ku_reject(x, KU_DIGITAL_SIGNATURE | KU_KEY_AGREEMENT))
613 return 0;
614 /* nsCertType if present should allow SSL client use */
615 if (ns_reject(x, NS_SSL_CLIENT))
616 return 0;
617 return 1;
618 }
619
620 /*
621 * Key usage needed for TLS/SSL server: digital signature, encipherment or
622 * key agreement. The ssl code can check this more thoroughly for individual
623 * key types.
624 */
625 #define KU_TLS \
626 KU_DIGITAL_SIGNATURE|KU_KEY_ENCIPHERMENT|KU_KEY_AGREEMENT
627
check_purpose_ssl_server(const X509_PURPOSE * xp,const X509 * x,int ca)628 static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x,
629 int ca)
630 {
631 if (xku_reject(x, XKU_SSL_SERVER | XKU_SGC))
632 return 0;
633 if (ca)
634 return check_ssl_ca(x);
635
636 if (ns_reject(x, NS_SSL_SERVER))
637 return 0;
638 if (ku_reject(x, KU_TLS))
639 return 0;
640
641 return 1;
642
643 }
644
check_purpose_ns_ssl_server(const X509_PURPOSE * xp,const X509 * x,int ca)645 static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x,
646 int ca)
647 {
648 int ret;
649 ret = check_purpose_ssl_server(xp, x, ca);
650 if (!ret || ca)
651 return ret;
652 /* We need to encipher or Netscape complains */
653 if (ku_reject(x, KU_KEY_ENCIPHERMENT))
654 return 0;
655 return ret;
656 }
657
658 /* common S/MIME checks */
purpose_smime(const X509 * x,int ca)659 static int purpose_smime(const X509 *x, int ca)
660 {
661 if (xku_reject(x, XKU_SMIME))
662 return 0;
663 if (ca) {
664 int ca_ret;
665 ca_ret = check_ca(x);
666 if (!ca_ret)
667 return 0;
668 /* check nsCertType if present */
669 if (ca_ret != 5 || x->ex_nscert & NS_SMIME_CA)
670 return ca_ret;
671 else
672 return 0;
673 }
674 if (x->ex_flags & EXFLAG_NSCERT) {
675 if (x->ex_nscert & NS_SMIME)
676 return 1;
677 /* Workaround for some buggy certificates */
678 if (x->ex_nscert & NS_SSL_CLIENT)
679 return 2;
680 return 0;
681 }
682 return 1;
683 }
684
check_purpose_smime_sign(const X509_PURPOSE * xp,const X509 * x,int ca)685 static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x,
686 int ca)
687 {
688 int ret;
689 ret = purpose_smime(x, ca);
690 if (!ret || ca)
691 return ret;
692 if (ku_reject(x, KU_DIGITAL_SIGNATURE | KU_NON_REPUDIATION))
693 return 0;
694 return ret;
695 }
696
check_purpose_smime_encrypt(const X509_PURPOSE * xp,const X509 * x,int ca)697 static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x,
698 int ca)
699 {
700 int ret;
701 ret = purpose_smime(x, ca);
702 if (!ret || ca)
703 return ret;
704 if (ku_reject(x, KU_KEY_ENCIPHERMENT))
705 return 0;
706 return ret;
707 }
708
check_purpose_crl_sign(const X509_PURPOSE * xp,const X509 * x,int ca)709 static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x,
710 int ca)
711 {
712 if (ca) {
713 int ca_ret;
714 if ((ca_ret = check_ca(x)) != 2)
715 return ca_ret;
716 else
717 return 0;
718 }
719 if (ku_reject(x, KU_CRL_SIGN))
720 return 0;
721 return 1;
722 }
723
724 /*
725 * OCSP helper: this is *not* a full OCSP check. It just checks that each CA
726 * is valid. Additional checks must be made on the chain.
727 */
728
ocsp_helper(const X509_PURPOSE * xp,const X509 * x,int ca)729 static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca)
730 {
731 /*
732 * Must be a valid CA. Should we really support the "I don't know" value
733 * (2)?
734 */
735 if (ca)
736 return check_ca(x);
737 /* leaf certificate is checked in OCSP_verify() */
738 return 1;
739 }
740
check_purpose_timestamp_sign(const X509_PURPOSE * xp,const X509 * x,int ca)741 static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x,
742 int ca)
743 {
744 int i_ext;
745
746 /* If ca is true we must return if this is a valid CA certificate. */
747 if (ca)
748 return check_ca(x);
749
750 /*
751 * Check the optional key usage field:
752 * if Key Usage is present, it must be one of digitalSignature
753 * and/or nonRepudiation (other values are not consistent and shall
754 * be rejected).
755 */
756 if ((x->ex_flags & EXFLAG_KUSAGE)
757 && ((x->ex_kusage & ~(KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE)) ||
758 !(x->ex_kusage & (KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE))))
759 return 0;
760
761 /* Only time stamp key usage is permitted and it's required. */
762 if (!(x->ex_flags & EXFLAG_XKUSAGE) || x->ex_xkusage != XKU_TIMESTAMP)
763 return 0;
764
765 /* Extended Key Usage MUST be critical */
766 i_ext = X509_get_ext_by_NID((X509 *)x, NID_ext_key_usage, -1);
767 if (i_ext >= 0) {
768 X509_EXTENSION *ext = X509_get_ext((X509 *)x, i_ext);
769 if (!X509_EXTENSION_get_critical(ext))
770 return 0;
771 }
772
773 return 1;
774 }
775
no_check(const X509_PURPOSE * xp,const X509 * x,int ca)776 static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca)
777 {
778 return 1;
779 }
780
781 /*-
782 * Various checks to see if one certificate issued the second.
783 * This can be used to prune a set of possible issuer certificates
784 * which have been looked up using some simple method such as by
785 * subject name.
786 * These are:
787 * 1. Check issuer_name(subject) == subject_name(issuer)
788 * 2. If akid(subject) exists check it matches issuer
789 * 3. If key_usage(issuer) exists check it supports certificate signing
790 * returns 0 for OK, positive for reason for mismatch, reasons match
791 * codes for X509_verify_cert()
792 */
793
X509_check_issued(X509 * issuer,X509 * subject)794 int X509_check_issued(X509 *issuer, X509 *subject)
795 {
796 if (X509_NAME_cmp(X509_get_subject_name(issuer),
797 X509_get_issuer_name(subject)))
798 return X509_V_ERR_SUBJECT_ISSUER_MISMATCH;
799
800 x509v3_cache_extensions(issuer);
801 x509v3_cache_extensions(subject);
802
803 if (subject->akid) {
804 int ret = X509_check_akid(issuer, subject->akid);
805 if (ret != X509_V_OK)
806 return ret;
807 }
808
809 if (subject->ex_flags & EXFLAG_PROXY) {
810 if (ku_reject(issuer, KU_DIGITAL_SIGNATURE))
811 return X509_V_ERR_KEYUSAGE_NO_DIGITAL_SIGNATURE;
812 } else if (ku_reject(issuer, KU_KEY_CERT_SIGN))
813 return X509_V_ERR_KEYUSAGE_NO_CERTSIGN;
814 return X509_V_OK;
815 }
816
X509_check_akid(X509 * issuer,AUTHORITY_KEYID * akid)817 int X509_check_akid(X509 *issuer, AUTHORITY_KEYID *akid)
818 {
819
820 if (!akid)
821 return X509_V_OK;
822
823 /* Check key ids (if present) */
824 if (akid->keyid && issuer->skid &&
825 ASN1_OCTET_STRING_cmp(akid->keyid, issuer->skid))
826 return X509_V_ERR_AKID_SKID_MISMATCH;
827 /* Check serial number */
828 if (akid->serial &&
829 ASN1_INTEGER_cmp(X509_get_serialNumber(issuer), akid->serial))
830 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH;
831 /* Check issuer name */
832 if (akid->issuer) {
833 /*
834 * Ugh, for some peculiar reason AKID includes SEQUENCE OF
835 * GeneralName. So look for a DirName. There may be more than one but
836 * we only take any notice of the first.
837 */
838 GENERAL_NAMES *gens;
839 GENERAL_NAME *gen;
840 X509_NAME *nm = NULL;
841 int i;
842 gens = akid->issuer;
843 for (i = 0; i < sk_GENERAL_NAME_num(gens); i++) {
844 gen = sk_GENERAL_NAME_value(gens, i);
845 if (gen->type == GEN_DIRNAME) {
846 nm = gen->d.dirn;
847 break;
848 }
849 }
850 if (nm && X509_NAME_cmp(nm, X509_get_issuer_name(issuer)))
851 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH;
852 }
853 return X509_V_OK;
854 }
855