1 /* v3_purp.c */
2 /* Written by Dr Stephen N Henson (steve@openssl.org) 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 *
25 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
26 * endorse or promote products derived from this software without
27 * prior written permission. For written permission, please contact
28 * licensing@OpenSSL.org.
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
40 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
41 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
42 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
43 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * (eay@cryptsoft.com). This product includes software written by Tim
55 * Hudson (tjh@cryptsoft.com). */
56
57 #include <stdio.h>
58
59 #include <openssl/buf.h>
60 #include <openssl/err.h>
61 #include <openssl/digest.h>
62 #include <openssl/mem.h>
63 #include <openssl/obj.h>
64 #include <openssl/x509_vfy.h>
65 #include <openssl/x509v3.h>
66
67
68 static void x509v3_cache_extensions(X509 *x);
69
70 static int check_ssl_ca(const X509 *x);
71 static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, int ca);
72 static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca);
73 static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, 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, int ca);
76 static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, int ca);
77 static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, int ca);
78 static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x, int ca);
79 static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca);
80 static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca);
81
82 static int xp_cmp(const X509_PURPOSE **a, const X509_PURPOSE **b);
83 static void xptable_free(X509_PURPOSE *p);
84
85 static X509_PURPOSE xstandard[] = {
86 {X509_PURPOSE_SSL_CLIENT, X509_TRUST_SSL_CLIENT, 0, check_purpose_ssl_client, (char *) "SSL client", (char *) "sslclient", NULL},
87 {X509_PURPOSE_SSL_SERVER, X509_TRUST_SSL_SERVER, 0, check_purpose_ssl_server, (char *) "SSL server", (char *) "sslserver", NULL},
88 {X509_PURPOSE_NS_SSL_SERVER, X509_TRUST_SSL_SERVER, 0, check_purpose_ns_ssl_server, (char *) "Netscape SSL server", (char *) "nssslserver", NULL},
89 {X509_PURPOSE_SMIME_SIGN, X509_TRUST_EMAIL, 0, check_purpose_smime_sign, (char *) "S/MIME signing", (char *) "smimesign", NULL},
90 {X509_PURPOSE_SMIME_ENCRYPT, X509_TRUST_EMAIL, 0, check_purpose_smime_encrypt, (char *) "S/MIME encryption", (char *) "smimeencrypt", NULL},
91 {X509_PURPOSE_CRL_SIGN, X509_TRUST_COMPAT, 0, check_purpose_crl_sign, (char *) "CRL signing", (char *) "crlsign", NULL},
92 {X509_PURPOSE_ANY, X509_TRUST_DEFAULT, 0, no_check, (char *) "Any Purpose", (char *) "any", NULL},
93 {X509_PURPOSE_OCSP_HELPER, X509_TRUST_COMPAT, 0, ocsp_helper, (char *) "OCSP helper", (char *) "ocsphelper", NULL},
94 {X509_PURPOSE_TIMESTAMP_SIGN, X509_TRUST_TSA, 0, check_purpose_timestamp_sign, (char *) "Time Stamp signing", (char *) "timestampsign", NULL},
95 };
96
97 #define X509_PURPOSE_COUNT (sizeof(xstandard)/sizeof(X509_PURPOSE))
98
99 static STACK_OF(X509_PURPOSE) *xptable = NULL;
100
xp_cmp(const X509_PURPOSE ** a,const X509_PURPOSE ** b)101 static int xp_cmp(const X509_PURPOSE **a, const X509_PURPOSE **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. */
X509_check_purpose(X509 * x,int id,int ca)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)) {
114 CRYPTO_w_lock(CRYPTO_LOCK_X509);
115 x509v3_cache_extensions(x);
116 CRYPTO_w_unlock(CRYPTO_LOCK_X509);
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
X509_PURPOSE_set(int * p,int purpose)125 int X509_PURPOSE_set(int *p, int purpose)
126 {
127 if(X509_PURPOSE_get_by_id(purpose) == -1) {
128 OPENSSL_PUT_ERROR(X509V3, X509_PURPOSE_set, X509V3_R_INVALID_PURPOSE);
129 return 0;
130 }
131 *p = purpose;
132 return 1;
133 }
134
X509_PURPOSE_get_count(void)135 int X509_PURPOSE_get_count(void)
136 {
137 if(!xptable) return X509_PURPOSE_COUNT;
138 return sk_X509_PURPOSE_num(xptable) + X509_PURPOSE_COUNT;
139 }
140
X509_PURPOSE_get0(int idx)141 X509_PURPOSE * X509_PURPOSE_get0(int idx)
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
X509_PURPOSE_get_by_sname(char * sname)148 int X509_PURPOSE_get_by_sname(char *sname)
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
X509_PURPOSE_get_by_id(int purpose)159 int X509_PURPOSE_get_by_id(int purpose)
160 {
161 X509_PURPOSE tmp;
162 size_t idx;
163
164 if((purpose >= X509_PURPOSE_MIN) && (purpose <= X509_PURPOSE_MAX))
165 return purpose - X509_PURPOSE_MIN;
166 tmp.purpose = purpose;
167 if(!xptable) return -1;
168
169 if (!sk_X509_PURPOSE_find(xptable, &idx, &tmp))
170 return -1;
171 return idx + X509_PURPOSE_COUNT;
172 }
173
X509_PURPOSE_add(int id,int trust,int flags,int (* ck)(const X509_PURPOSE *,const X509 *,int),char * name,char * sname,void * arg)174 int X509_PURPOSE_add(int id, int trust, int flags,
175 int (*ck)(const X509_PURPOSE *, const X509 *, int),
176 char *name, char *sname, void *arg)
177 {
178 int idx;
179 X509_PURPOSE *ptmp;
180 /* This is set according to what we change: application can't set it */
181 flags &= ~X509_PURPOSE_DYNAMIC;
182 /* This will always be set for application modified trust entries */
183 flags |= X509_PURPOSE_DYNAMIC_NAME;
184 /* Get existing entry if any */
185 idx = X509_PURPOSE_get_by_id(id);
186 /* Need a new entry */
187 if(idx == -1) {
188 if(!(ptmp = OPENSSL_malloc(sizeof(X509_PURPOSE)))) {
189 OPENSSL_PUT_ERROR(X509V3, X509_PURPOSE_add, ERR_R_MALLOC_FAILURE);
190 return 0;
191 }
192 ptmp->flags = X509_PURPOSE_DYNAMIC;
193 } else ptmp = X509_PURPOSE_get0(idx);
194
195 /* OPENSSL_free existing name if dynamic */
196 if(ptmp->flags & X509_PURPOSE_DYNAMIC_NAME) {
197 OPENSSL_free(ptmp->name);
198 OPENSSL_free(ptmp->sname);
199 }
200 /* dup supplied name */
201 ptmp->name = BUF_strdup(name);
202 ptmp->sname = BUF_strdup(sname);
203 if(!ptmp->name || !ptmp->sname) {
204 OPENSSL_PUT_ERROR(X509V3, X509_PURPOSE_add, ERR_R_MALLOC_FAILURE);
205 return 0;
206 }
207 /* Keep the dynamic flag of existing entry */
208 ptmp->flags &= X509_PURPOSE_DYNAMIC;
209 /* Set all other flags */
210 ptmp->flags |= flags;
211
212 ptmp->purpose = id;
213 ptmp->trust = trust;
214 ptmp->check_purpose = ck;
215 ptmp->usr_data = arg;
216
217 /* If its a new entry manage the dynamic table */
218 if(idx == -1) {
219 if(!xptable && !(xptable = sk_X509_PURPOSE_new(xp_cmp))) {
220 OPENSSL_PUT_ERROR(X509V3, X509_PURPOSE_add, ERR_R_MALLOC_FAILURE);
221 return 0;
222 }
223 if (!sk_X509_PURPOSE_push(xptable, ptmp)) {
224 OPENSSL_PUT_ERROR(X509V3, X509_PURPOSE_add, ERR_R_MALLOC_FAILURE);
225 return 0;
226 }
227 }
228 return 1;
229 }
230
xptable_free(X509_PURPOSE * p)231 static void xptable_free(X509_PURPOSE *p)
232 {
233 if(!p) return;
234 if (p->flags & X509_PURPOSE_DYNAMIC)
235 {
236 if (p->flags & X509_PURPOSE_DYNAMIC_NAME) {
237 OPENSSL_free(p->name);
238 OPENSSL_free(p->sname);
239 }
240 OPENSSL_free(p);
241 }
242 }
243
X509_PURPOSE_cleanup(void)244 void X509_PURPOSE_cleanup(void)
245 {
246 unsigned int i;
247 sk_X509_PURPOSE_pop_free(xptable, xptable_free);
248 for(i = 0; i < X509_PURPOSE_COUNT; i++) xptable_free(xstandard + i);
249 xptable = NULL;
250 }
251
X509_PURPOSE_get_id(X509_PURPOSE * xp)252 int X509_PURPOSE_get_id(X509_PURPOSE *xp)
253 {
254 return xp->purpose;
255 }
256
X509_PURPOSE_get0_name(X509_PURPOSE * xp)257 char *X509_PURPOSE_get0_name(X509_PURPOSE *xp)
258 {
259 return xp->name;
260 }
261
X509_PURPOSE_get0_sname(X509_PURPOSE * xp)262 char *X509_PURPOSE_get0_sname(X509_PURPOSE *xp)
263 {
264 return xp->sname;
265 }
266
X509_PURPOSE_get_trust(X509_PURPOSE * xp)267 int X509_PURPOSE_get_trust(X509_PURPOSE *xp)
268 {
269 return xp->trust;
270 }
271
nid_cmp(const void * void_a,const void * void_b)272 static int nid_cmp(const void *void_a, const void *void_b)
273 {
274 const int *a = void_a, *b = void_b;
275
276 return *a - *b;
277 }
278
X509_supported_extension(X509_EXTENSION * ex)279 int X509_supported_extension(X509_EXTENSION *ex)
280 {
281 /* This table is a list of the NIDs of supported extensions:
282 * that is those which are used by the verify process. If
283 * an extension is critical and doesn't appear in this list
284 * then the verify process will normally reject the certificate.
285 * The list must be kept in numerical order because it will be
286 * searched using bsearch.
287 */
288
289 static const int supported_nids[] = {
290 NID_netscape_cert_type, /* 71 */
291 NID_key_usage, /* 83 */
292 NID_subject_alt_name, /* 85 */
293 NID_basic_constraints, /* 87 */
294 NID_certificate_policies, /* 89 */
295 NID_ext_key_usage, /* 126 */
296 NID_policy_constraints, /* 401 */
297 NID_proxyCertInfo, /* 663 */
298 NID_name_constraints, /* 666 */
299 NID_policy_mappings, /* 747 */
300 NID_inhibit_any_policy /* 748 */
301 };
302
303 int ex_nid = OBJ_obj2nid(X509_EXTENSION_get_object(ex));
304
305 if (ex_nid == NID_undef)
306 return 0;
307
308 if (bsearch(&ex_nid, supported_nids, sizeof(supported_nids)/sizeof(int), sizeof(int), nid_cmp) != NULL)
309 return 1;
310 return 0;
311 }
312
setup_dp(X509 * x,DIST_POINT * dp)313 static void setup_dp(X509 *x, DIST_POINT *dp)
314 {
315 X509_NAME *iname = NULL;
316 size_t i;
317 if (dp->reasons)
318 {
319 if (dp->reasons->length > 0)
320 dp->dp_reasons = dp->reasons->data[0];
321 if (dp->reasons->length > 1)
322 dp->dp_reasons |= (dp->reasons->data[1] << 8);
323 dp->dp_reasons &= CRLDP_ALL_REASONS;
324 }
325 else
326 dp->dp_reasons = CRLDP_ALL_REASONS;
327 if (!dp->distpoint || (dp->distpoint->type != 1))
328 return;
329 for (i = 0; i < sk_GENERAL_NAME_num(dp->CRLissuer); i++)
330 {
331 GENERAL_NAME *gen = sk_GENERAL_NAME_value(dp->CRLissuer, i);
332 if (gen->type == GEN_DIRNAME)
333 {
334 iname = gen->d.directoryName;
335 break;
336 }
337 }
338 if (!iname)
339 iname = X509_get_issuer_name(x);
340
341 DIST_POINT_set_dpname(dp->distpoint, iname);
342
343 }
344
setup_crldp(X509 * x)345 static void setup_crldp(X509 *x)
346 {
347 size_t i;
348 x->crldp = X509_get_ext_d2i(x, NID_crl_distribution_points, NULL, NULL);
349 for (i = 0; i < sk_DIST_POINT_num(x->crldp); i++)
350 setup_dp(x, sk_DIST_POINT_value(x->crldp, i));
351 }
352
x509v3_cache_extensions(X509 * x)353 static void x509v3_cache_extensions(X509 *x)
354 {
355 BASIC_CONSTRAINTS *bs;
356 PROXY_CERT_INFO_EXTENSION *pci;
357 ASN1_BIT_STRING *usage;
358 ASN1_BIT_STRING *ns;
359 EXTENDED_KEY_USAGE *extusage;
360 X509_EXTENSION *ex;
361 size_t i;
362 int j;
363 if(x->ex_flags & EXFLAG_SET) return;
364 X509_digest(x, EVP_sha1(), x->sha1_hash, NULL);
365 /* V1 should mean no extensions ... */
366 if(!X509_get_version(x)) x->ex_flags |= EXFLAG_V1;
367 /* Handle basic constraints */
368 if((bs=X509_get_ext_d2i(x, NID_basic_constraints, NULL, NULL))) {
369 if(bs->ca) x->ex_flags |= EXFLAG_CA;
370 if(bs->pathlen) {
371 if((bs->pathlen->type == V_ASN1_NEG_INTEGER)
372 || !bs->ca) {
373 x->ex_flags |= EXFLAG_INVALID;
374 x->ex_pathlen = 0;
375 } else x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen);
376 } else x->ex_pathlen = -1;
377 BASIC_CONSTRAINTS_free(bs);
378 x->ex_flags |= EXFLAG_BCONS;
379 }
380 /* Handle proxy certificates */
381 if((pci=X509_get_ext_d2i(x, NID_proxyCertInfo, NULL, NULL))) {
382 if (x->ex_flags & EXFLAG_CA
383 || X509_get_ext_by_NID(x, NID_subject_alt_name, -1) >= 0
384 || X509_get_ext_by_NID(x, NID_issuer_alt_name, -1) >= 0) {
385 x->ex_flags |= EXFLAG_INVALID;
386 }
387 if (pci->pcPathLengthConstraint) {
388 x->ex_pcpathlen =
389 ASN1_INTEGER_get(pci->pcPathLengthConstraint);
390 } else x->ex_pcpathlen = -1;
391 PROXY_CERT_INFO_EXTENSION_free(pci);
392 x->ex_flags |= EXFLAG_PROXY;
393 }
394 /* Handle key usage */
395 if((usage=X509_get_ext_d2i(x, NID_key_usage, NULL, NULL))) {
396 if(usage->length > 0) {
397 x->ex_kusage = usage->data[0];
398 if(usage->length > 1)
399 x->ex_kusage |= usage->data[1] << 8;
400 } else x->ex_kusage = 0;
401 x->ex_flags |= EXFLAG_KUSAGE;
402 ASN1_BIT_STRING_free(usage);
403 }
404 x->ex_xkusage = 0;
405 if((extusage=X509_get_ext_d2i(x, NID_ext_key_usage, NULL, NULL))) {
406 x->ex_flags |= EXFLAG_XKUSAGE;
407 for(i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) {
408 switch(OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage,i))) {
409 case NID_server_auth:
410 x->ex_xkusage |= XKU_SSL_SERVER;
411 break;
412
413 case NID_client_auth:
414 x->ex_xkusage |= XKU_SSL_CLIENT;
415 break;
416
417 case NID_email_protect:
418 x->ex_xkusage |= XKU_SMIME;
419 break;
420
421 case NID_code_sign:
422 x->ex_xkusage |= XKU_CODE_SIGN;
423 break;
424
425 case NID_ms_sgc:
426 case NID_ns_sgc:
427 x->ex_xkusage |= XKU_SGC;
428 break;
429
430 case NID_OCSP_sign:
431 x->ex_xkusage |= XKU_OCSP_SIGN;
432 break;
433
434 case NID_time_stamp:
435 x->ex_xkusage |= XKU_TIMESTAMP;
436 break;
437
438 case NID_dvcs:
439 x->ex_xkusage |= XKU_DVCS;
440 break;
441
442 case NID_anyExtendedKeyUsage:
443 x->ex_xkusage |= XKU_ANYEKU;
444 break;
445 }
446 }
447 sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free);
448 }
449
450 if((ns=X509_get_ext_d2i(x, NID_netscape_cert_type, NULL, NULL))) {
451 if(ns->length > 0) x->ex_nscert = ns->data[0];
452 else x->ex_nscert = 0;
453 x->ex_flags |= EXFLAG_NSCERT;
454 ASN1_BIT_STRING_free(ns);
455 }
456 x->skid =X509_get_ext_d2i(x, NID_subject_key_identifier, NULL, NULL);
457 x->akid =X509_get_ext_d2i(x, NID_authority_key_identifier, NULL, NULL);
458 /* Does subject name match issuer ? */
459 if(!X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x)))
460 {
461 x->ex_flags |= EXFLAG_SI;
462 /* If SKID matches AKID also indicate self signed */
463 if (X509_check_akid(x, x->akid) == X509_V_OK)
464 x->ex_flags |= EXFLAG_SS;
465 }
466 x->altname = X509_get_ext_d2i(x, NID_subject_alt_name, NULL, NULL);
467 x->nc = X509_get_ext_d2i(x, NID_name_constraints, &j, NULL);
468 if (!x->nc && (j != -1))
469 x->ex_flags |= EXFLAG_INVALID;
470 setup_crldp(x);
471
472 for (j = 0; j < X509_get_ext_count(x); j++)
473 {
474 ex = X509_get_ext(x, j);
475 if (OBJ_obj2nid(X509_EXTENSION_get_object(ex))
476 == NID_freshest_crl)
477 x->ex_flags |= EXFLAG_FRESHEST;
478 if (!X509_EXTENSION_get_critical(ex))
479 continue;
480 if (!X509_supported_extension(ex))
481 {
482 x->ex_flags |= EXFLAG_CRITICAL;
483 break;
484 }
485 }
486 x->ex_flags |= EXFLAG_SET;
487 }
488
489 /* CA checks common to all purposes
490 * return codes:
491 * 0 not a CA
492 * 1 is a CA
493 * 2 basicConstraints absent so "maybe" a CA
494 * 3 basicConstraints absent but self signed V1.
495 * 4 basicConstraints absent but keyUsage present and keyCertSign asserted.
496 */
497
498 #define V1_ROOT (EXFLAG_V1|EXFLAG_SS)
499 #define ku_reject(x, usage) \
500 (((x)->ex_flags & EXFLAG_KUSAGE) && !((x)->ex_kusage & (usage)))
501 #define xku_reject(x, usage) \
502 (((x)->ex_flags & EXFLAG_XKUSAGE) && !((x)->ex_xkusage & (usage)))
503 #define ns_reject(x, usage) \
504 (((x)->ex_flags & EXFLAG_NSCERT) && !((x)->ex_nscert & (usage)))
505
check_ca(const X509 * x)506 static int check_ca(const X509 *x)
507 {
508 /* keyUsage if present should allow cert signing */
509 if(ku_reject(x, KU_KEY_CERT_SIGN)) return 0;
510 if(x->ex_flags & EXFLAG_BCONS) {
511 if(x->ex_flags & EXFLAG_CA) return 1;
512 /* If basicConstraints says not a CA then say so */
513 else return 0;
514 } else {
515 /* we support V1 roots for... uh, I don't really know why. */
516 if((x->ex_flags & V1_ROOT) == V1_ROOT) return 3;
517 /* If key usage present it must have certSign so tolerate it */
518 else if (x->ex_flags & EXFLAG_KUSAGE) return 4;
519 /* Older certificates could have Netscape-specific CA types */
520 else if (x->ex_flags & EXFLAG_NSCERT
521 && x->ex_nscert & NS_ANY_CA) return 5;
522 /* can this still be regarded a CA certificate? I doubt it */
523 return 0;
524 }
525 }
526
X509_check_ca(X509 * x)527 int X509_check_ca(X509 *x)
528 {
529 if(!(x->ex_flags & EXFLAG_SET)) {
530 CRYPTO_w_lock(CRYPTO_LOCK_X509);
531 x509v3_cache_extensions(x);
532 CRYPTO_w_unlock(CRYPTO_LOCK_X509);
533 }
534
535 return check_ca(x);
536 }
537
538 /* Check SSL CA: common checks for SSL client and server */
check_ssl_ca(const X509 * x)539 static int check_ssl_ca(const X509 *x)
540 {
541 int ca_ret;
542 ca_ret = check_ca(x);
543 if(!ca_ret) return 0;
544 /* check nsCertType if present */
545 if(ca_ret != 5 || x->ex_nscert & NS_SSL_CA) return ca_ret;
546 else return 0;
547 }
548
549
check_purpose_ssl_client(const X509_PURPOSE * xp,const X509 * x,int ca)550 static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, int ca)
551 {
552 if(xku_reject(x,XKU_SSL_CLIENT)) return 0;
553 if(ca) return check_ssl_ca(x);
554 /* We need to do digital signatures or key agreement */
555 if(ku_reject(x,KU_DIGITAL_SIGNATURE|KU_KEY_AGREEMENT)) return 0;
556 /* nsCertType if present should allow SSL client use */
557 if(ns_reject(x, NS_SSL_CLIENT)) return 0;
558 return 1;
559 }
560 /* Key usage needed for TLS/SSL server: digital signature, encipherment or
561 * key agreement. The ssl code can check this more thoroughly for individual
562 * key types.
563 */
564 #define KU_TLS \
565 KU_DIGITAL_SIGNATURE|KU_KEY_ENCIPHERMENT|KU_KEY_AGREEMENT
566
check_purpose_ssl_server(const X509_PURPOSE * xp,const X509 * x,int ca)567 static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca)
568 {
569 if(xku_reject(x,XKU_SSL_SERVER|XKU_SGC)) return 0;
570 if(ca) return check_ssl_ca(x);
571
572 if(ns_reject(x, NS_SSL_SERVER)) return 0;
573 if(ku_reject(x, KU_TLS)) return 0;
574
575 return 1;
576
577 }
578
check_purpose_ns_ssl_server(const X509_PURPOSE * xp,const X509 * x,int ca)579 static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca)
580 {
581 int ret;
582 ret = check_purpose_ssl_server(xp, x, ca);
583 if(!ret || ca) return ret;
584 /* We need to encipher or Netscape complains */
585 if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0;
586 return ret;
587 }
588
589 /* common S/MIME checks */
purpose_smime(const X509 * x,int ca)590 static int purpose_smime(const X509 *x, int ca)
591 {
592 if(xku_reject(x,XKU_SMIME)) return 0;
593 if(ca) {
594 int ca_ret;
595 ca_ret = check_ca(x);
596 if(!ca_ret) return 0;
597 /* check nsCertType if present */
598 if(ca_ret != 5 || x->ex_nscert & NS_SMIME_CA) return ca_ret;
599 else return 0;
600 }
601 if(x->ex_flags & EXFLAG_NSCERT) {
602 if(x->ex_nscert & NS_SMIME) return 1;
603 /* Workaround for some buggy certificates */
604 if(x->ex_nscert & NS_SSL_CLIENT) return 2;
605 return 0;
606 }
607 return 1;
608 }
609
check_purpose_smime_sign(const X509_PURPOSE * xp,const X509 * x,int ca)610 static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, int ca)
611 {
612 int ret;
613 ret = purpose_smime(x, ca);
614 if(!ret || ca) return ret;
615 if(ku_reject(x, KU_DIGITAL_SIGNATURE|KU_NON_REPUDIATION)) return 0;
616 return ret;
617 }
618
check_purpose_smime_encrypt(const X509_PURPOSE * xp,const X509 * x,int ca)619 static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, int ca)
620 {
621 int ret;
622 ret = purpose_smime(x, ca);
623 if(!ret || ca) return ret;
624 if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0;
625 return ret;
626 }
627
check_purpose_crl_sign(const X509_PURPOSE * xp,const X509 * x,int ca)628 static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, int ca)
629 {
630 if(ca) {
631 int ca_ret;
632 if((ca_ret = check_ca(x)) != 2) return ca_ret;
633 else return 0;
634 }
635 if(ku_reject(x, KU_CRL_SIGN)) return 0;
636 return 1;
637 }
638
639 /* OCSP helper: this is *not* a full OCSP check. It just checks that
640 * each CA is valid. Additional checks must be made on the chain.
641 */
642
ocsp_helper(const X509_PURPOSE * xp,const X509 * x,int ca)643 static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca)
644 {
645 /* Must be a valid CA. Should we really support the "I don't know"
646 value (2)? */
647 if(ca) return check_ca(x);
648 /* leaf certificate is checked in OCSP_verify() */
649 return 1;
650 }
651
check_purpose_timestamp_sign(const X509_PURPOSE * xp,const X509 * x,int ca)652 static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x,
653 int ca)
654 {
655 int i_ext;
656
657 /* If ca is true we must return if this is a valid CA certificate. */
658 if (ca) return check_ca(x);
659
660 /*
661 * Check the optional key usage field:
662 * if Key Usage is present, it must be one of digitalSignature
663 * and/or nonRepudiation (other values are not consistent and shall
664 * be rejected).
665 */
666 if ((x->ex_flags & EXFLAG_KUSAGE)
667 && ((x->ex_kusage & ~(KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE)) ||
668 !(x->ex_kusage & (KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE))))
669 return 0;
670
671 /* Only time stamp key usage is permitted and it's required. */
672 if (!(x->ex_flags & EXFLAG_XKUSAGE) || x->ex_xkusage != XKU_TIMESTAMP)
673 return 0;
674
675 /* Extended Key Usage MUST be critical */
676 i_ext = X509_get_ext_by_NID((X509 *) x, NID_ext_key_usage, -1);
677 if (i_ext >= 0)
678 {
679 X509_EXTENSION *ext = X509_get_ext((X509 *) x, i_ext);
680 if (!X509_EXTENSION_get_critical(ext))
681 return 0;
682 }
683
684 return 1;
685 }
686
no_check(const X509_PURPOSE * xp,const X509 * x,int ca)687 static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca)
688 {
689 return 1;
690 }
691
692 /* Various checks to see if one certificate issued the second.
693 * This can be used to prune a set of possible issuer certificates
694 * which have been looked up using some simple method such as by
695 * subject name.
696 * These are:
697 * 1. Check issuer_name(subject) == subject_name(issuer)
698 * 2. If akid(subject) exists check it matches issuer
699 * 3. If key_usage(issuer) exists check it supports certificate signing
700 * returns 0 for OK, positive for reason for mismatch, reasons match
701 * codes for X509_verify_cert()
702 */
703
X509_check_issued(X509 * issuer,X509 * subject)704 int X509_check_issued(X509 *issuer, X509 *subject)
705 {
706 if(X509_NAME_cmp(X509_get_subject_name(issuer),
707 X509_get_issuer_name(subject)))
708 return X509_V_ERR_SUBJECT_ISSUER_MISMATCH;
709 x509v3_cache_extensions(issuer);
710 x509v3_cache_extensions(subject);
711
712 if(subject->akid)
713 {
714 int ret = X509_check_akid(issuer, subject->akid);
715 if (ret != X509_V_OK)
716 return ret;
717 }
718
719 if(subject->ex_flags & EXFLAG_PROXY)
720 {
721 if(ku_reject(issuer, KU_DIGITAL_SIGNATURE))
722 return X509_V_ERR_KEYUSAGE_NO_DIGITAL_SIGNATURE;
723 }
724 else if(ku_reject(issuer, KU_KEY_CERT_SIGN))
725 return X509_V_ERR_KEYUSAGE_NO_CERTSIGN;
726 return X509_V_OK;
727 }
728
X509_check_akid(X509 * issuer,AUTHORITY_KEYID * akid)729 int X509_check_akid(X509 *issuer, AUTHORITY_KEYID *akid)
730 {
731
732 if(!akid)
733 return X509_V_OK;
734
735 /* Check key ids (if present) */
736 if(akid->keyid && issuer->skid &&
737 ASN1_OCTET_STRING_cmp(akid->keyid, issuer->skid) )
738 return X509_V_ERR_AKID_SKID_MISMATCH;
739 /* Check serial number */
740 if(akid->serial &&
741 ASN1_INTEGER_cmp(X509_get_serialNumber(issuer), akid->serial))
742 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH;
743 /* Check issuer name */
744 if(akid->issuer)
745 {
746 /* Ugh, for some peculiar reason AKID includes
747 * SEQUENCE OF GeneralName. So look for a DirName.
748 * There may be more than one but we only take any
749 * notice of the first.
750 */
751 GENERAL_NAMES *gens;
752 GENERAL_NAME *gen;
753 X509_NAME *nm = NULL;
754 size_t i;
755 gens = akid->issuer;
756 for(i = 0; i < sk_GENERAL_NAME_num(gens); i++)
757 {
758 gen = sk_GENERAL_NAME_value(gens, i);
759 if(gen->type == GEN_DIRNAME)
760 {
761 nm = gen->d.dirn;
762 break;
763 }
764 }
765 if(nm && X509_NAME_cmp(nm, X509_get_issuer_name(issuer)))
766 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH;
767 }
768 return X509_V_OK;
769 }
770
771