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 <string.h>
60
61 #include <openssl/buf.h>
62 #include <openssl/err.h>
63 #include <openssl/digest.h>
64 #include <openssl/mem.h>
65 #include <openssl/obj.h>
66 #include <openssl/thread.h>
67 #include <openssl/x509_vfy.h>
68 #include <openssl/x509v3.h>
69
70 #include "../internal.h"
71
72
73 static void x509v3_cache_extensions(X509 *x);
74
75 static int check_ssl_ca(const X509 *x);
76 static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, int ca);
77 static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca);
78 static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca);
79 static int purpose_smime(const X509 *x, int ca);
80 static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, int ca);
81 static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, int ca);
82 static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, int ca);
83 static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x, int ca);
84 static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca);
85 static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca);
86
87 static int xp_cmp(const X509_PURPOSE **a, const X509_PURPOSE **b);
88 static void xptable_free(X509_PURPOSE *p);
89
90 static X509_PURPOSE xstandard[] = {
91 {X509_PURPOSE_SSL_CLIENT, X509_TRUST_SSL_CLIENT, 0, check_purpose_ssl_client, (char *) "SSL client", (char *) "sslclient", NULL},
92 {X509_PURPOSE_SSL_SERVER, X509_TRUST_SSL_SERVER, 0, check_purpose_ssl_server, (char *) "SSL server", (char *) "sslserver", NULL},
93 {X509_PURPOSE_NS_SSL_SERVER, X509_TRUST_SSL_SERVER, 0, check_purpose_ns_ssl_server, (char *) "Netscape SSL server", (char *) "nssslserver", NULL},
94 {X509_PURPOSE_SMIME_SIGN, X509_TRUST_EMAIL, 0, check_purpose_smime_sign, (char *) "S/MIME signing", (char *) "smimesign", NULL},
95 {X509_PURPOSE_SMIME_ENCRYPT, X509_TRUST_EMAIL, 0, check_purpose_smime_encrypt, (char *) "S/MIME encryption", (char *) "smimeencrypt", NULL},
96 {X509_PURPOSE_CRL_SIGN, X509_TRUST_COMPAT, 0, check_purpose_crl_sign, (char *) "CRL signing", (char *) "crlsign", NULL},
97 {X509_PURPOSE_ANY, X509_TRUST_DEFAULT, 0, no_check, (char *) "Any Purpose", (char *) "any", NULL},
98 {X509_PURPOSE_OCSP_HELPER, X509_TRUST_COMPAT, 0, ocsp_helper, (char *) "OCSP helper", (char *) "ocsphelper", NULL},
99 {X509_PURPOSE_TIMESTAMP_SIGN, X509_TRUST_TSA, 0, check_purpose_timestamp_sign, (char *) "Time Stamp signing", (char *) "timestampsign", NULL},
100 };
101
102 #define X509_PURPOSE_COUNT (sizeof(xstandard)/sizeof(X509_PURPOSE))
103
104 static STACK_OF(X509_PURPOSE) *xptable = NULL;
105
xp_cmp(const X509_PURPOSE ** a,const X509_PURPOSE ** b)106 static int xp_cmp(const X509_PURPOSE **a, const X509_PURPOSE **b)
107 {
108 return (*a)->purpose - (*b)->purpose;
109 }
110
111 /* As much as I'd like to make X509_check_purpose use a "const" X509*
112 * I really can't because it does recalculate hashes and do other non-const
113 * things. */
X509_check_purpose(X509 * x,int id,int ca)114 int X509_check_purpose(X509 *x, int id, int ca)
115 {
116 int idx;
117 const X509_PURPOSE *pt;
118 if(!(x->ex_flags & EXFLAG_SET)) {
119 x509v3_cache_extensions(x);
120 }
121 if(id == -1) return 1;
122 idx = X509_PURPOSE_get_by_id(id);
123 if(idx == -1) return -1;
124 pt = X509_PURPOSE_get0(idx);
125 return pt->check_purpose(pt, x, ca);
126 }
127
X509_PURPOSE_set(int * p,int purpose)128 int X509_PURPOSE_set(int *p, int purpose)
129 {
130 if(X509_PURPOSE_get_by_id(purpose) == -1) {
131 OPENSSL_PUT_ERROR(X509V3, X509_PURPOSE_set, X509V3_R_INVALID_PURPOSE);
132 return 0;
133 }
134 *p = purpose;
135 return 1;
136 }
137
X509_PURPOSE_get_count(void)138 int X509_PURPOSE_get_count(void)
139 {
140 if(!xptable) return X509_PURPOSE_COUNT;
141 return sk_X509_PURPOSE_num(xptable) + X509_PURPOSE_COUNT;
142 }
143
X509_PURPOSE_get0(int idx)144 X509_PURPOSE * X509_PURPOSE_get0(int idx)
145 {
146 if(idx < 0) return NULL;
147 if(idx < (int)X509_PURPOSE_COUNT) return xstandard + idx;
148 return sk_X509_PURPOSE_value(xptable, idx - X509_PURPOSE_COUNT);
149 }
150
X509_PURPOSE_get_by_sname(char * sname)151 int X509_PURPOSE_get_by_sname(char *sname)
152 {
153 int i;
154 X509_PURPOSE *xptmp;
155 for(i = 0; i < X509_PURPOSE_get_count(); i++) {
156 xptmp = X509_PURPOSE_get0(i);
157 if(!strcmp(xptmp->sname, sname)) return i;
158 }
159 return -1;
160 }
161
X509_PURPOSE_get_by_id(int purpose)162 int X509_PURPOSE_get_by_id(int purpose)
163 {
164 X509_PURPOSE tmp;
165 size_t idx;
166
167 if((purpose >= X509_PURPOSE_MIN) && (purpose <= X509_PURPOSE_MAX))
168 return purpose - X509_PURPOSE_MIN;
169 tmp.purpose = purpose;
170 if(!xptable) return -1;
171
172 if (!sk_X509_PURPOSE_find(xptable, &idx, &tmp))
173 return -1;
174 return idx + X509_PURPOSE_COUNT;
175 }
176
X509_PURPOSE_add(int id,int trust,int flags,int (* ck)(const X509_PURPOSE *,const X509 *,int),char * name,char * sname,void * arg)177 int X509_PURPOSE_add(int id, int trust, int flags,
178 int (*ck)(const X509_PURPOSE *, const X509 *, int),
179 char *name, char *sname, void *arg)
180 {
181 int idx;
182 X509_PURPOSE *ptmp;
183 char *name_dup, *sname_dup;
184
185 /* This is set according to what we change: application can't set it */
186 flags &= ~X509_PURPOSE_DYNAMIC;
187 /* This will always be set for application modified trust entries */
188 flags |= X509_PURPOSE_DYNAMIC_NAME;
189 /* Get existing entry if any */
190 idx = X509_PURPOSE_get_by_id(id);
191 /* Need a new entry */
192 if(idx == -1) {
193 if(!(ptmp = OPENSSL_malloc(sizeof(X509_PURPOSE)))) {
194 OPENSSL_PUT_ERROR(X509V3, X509_PURPOSE_add, ERR_R_MALLOC_FAILURE);
195 return 0;
196 }
197 ptmp->flags = X509_PURPOSE_DYNAMIC;
198 } else ptmp = X509_PURPOSE_get0(idx);
199
200 /* Duplicate the supplied names. */
201 name_dup = BUF_strdup(name);
202 sname_dup = BUF_strdup(sname);
203 if (name_dup == NULL || sname_dup == NULL) {
204 OPENSSL_PUT_ERROR(X509V3, X509_PURPOSE_add, ERR_R_MALLOC_FAILURE);
205 if (name_dup != NULL)
206 OPENSSL_free(name_dup);
207 if (sname_dup != NULL)
208 OPENSSL_free(sname_dup);
209 if (idx == -1)
210 OPENSSL_free(ptmp);
211 return 0;
212 }
213
214 /* OPENSSL_free existing name if dynamic */
215 if(ptmp->flags & X509_PURPOSE_DYNAMIC_NAME) {
216 OPENSSL_free(ptmp->name);
217 OPENSSL_free(ptmp->sname);
218 }
219 /* dup supplied name */
220 ptmp->name = name_dup;
221 ptmp->sname = sname_dup;
222 /* Keep the dynamic flag of existing entry */
223 ptmp->flags &= X509_PURPOSE_DYNAMIC;
224 /* Set all other flags */
225 ptmp->flags |= flags;
226
227 ptmp->purpose = id;
228 ptmp->trust = trust;
229 ptmp->check_purpose = ck;
230 ptmp->usr_data = arg;
231
232 /* If its a new entry manage the dynamic table */
233 if(idx == -1) {
234 if(!xptable && !(xptable = sk_X509_PURPOSE_new(xp_cmp))) {
235 OPENSSL_PUT_ERROR(X509V3, X509_PURPOSE_add, ERR_R_MALLOC_FAILURE);
236 xptable_free(ptmp);
237 return 0;
238 }
239 if (!sk_X509_PURPOSE_push(xptable, ptmp)) {
240 OPENSSL_PUT_ERROR(X509V3, X509_PURPOSE_add, ERR_R_MALLOC_FAILURE);
241 xptable_free(ptmp);
242 return 0;
243 }
244 }
245 return 1;
246 }
247
xptable_free(X509_PURPOSE * p)248 static void xptable_free(X509_PURPOSE *p)
249 {
250 if(!p) return;
251 if (p->flags & X509_PURPOSE_DYNAMIC)
252 {
253 if (p->flags & X509_PURPOSE_DYNAMIC_NAME) {
254 OPENSSL_free(p->name);
255 OPENSSL_free(p->sname);
256 }
257 OPENSSL_free(p);
258 }
259 }
260
X509_PURPOSE_cleanup(void)261 void X509_PURPOSE_cleanup(void)
262 {
263 unsigned int i;
264 sk_X509_PURPOSE_pop_free(xptable, xptable_free);
265 for(i = 0; i < X509_PURPOSE_COUNT; i++) xptable_free(xstandard + i);
266 xptable = NULL;
267 }
268
X509_PURPOSE_get_id(X509_PURPOSE * xp)269 int X509_PURPOSE_get_id(X509_PURPOSE *xp)
270 {
271 return xp->purpose;
272 }
273
X509_PURPOSE_get0_name(X509_PURPOSE * xp)274 char *X509_PURPOSE_get0_name(X509_PURPOSE *xp)
275 {
276 return xp->name;
277 }
278
X509_PURPOSE_get0_sname(X509_PURPOSE * xp)279 char *X509_PURPOSE_get0_sname(X509_PURPOSE *xp)
280 {
281 return xp->sname;
282 }
283
X509_PURPOSE_get_trust(X509_PURPOSE * xp)284 int X509_PURPOSE_get_trust(X509_PURPOSE *xp)
285 {
286 return xp->trust;
287 }
288
nid_cmp(const void * void_a,const void * void_b)289 static int nid_cmp(const void *void_a, const void *void_b)
290 {
291 const int *a = void_a, *b = void_b;
292
293 return *a - *b;
294 }
295
X509_supported_extension(X509_EXTENSION * ex)296 int X509_supported_extension(X509_EXTENSION *ex)
297 {
298 /* This table is a list of the NIDs of supported extensions:
299 * that is those which are used by the verify process. If
300 * an extension is critical and doesn't appear in this list
301 * then the verify process will normally reject the certificate.
302 * The list must be kept in numerical order because it will be
303 * searched using bsearch.
304 */
305
306 static const int supported_nids[] = {
307 NID_netscape_cert_type, /* 71 */
308 NID_key_usage, /* 83 */
309 NID_subject_alt_name, /* 85 */
310 NID_basic_constraints, /* 87 */
311 NID_certificate_policies, /* 89 */
312 NID_ext_key_usage, /* 126 */
313 NID_policy_constraints, /* 401 */
314 NID_proxyCertInfo, /* 663 */
315 NID_name_constraints, /* 666 */
316 NID_policy_mappings, /* 747 */
317 NID_inhibit_any_policy /* 748 */
318 };
319
320 int ex_nid = OBJ_obj2nid(X509_EXTENSION_get_object(ex));
321
322 if (ex_nid == NID_undef)
323 return 0;
324
325 if (bsearch(&ex_nid, supported_nids, sizeof(supported_nids)/sizeof(int), sizeof(int), nid_cmp) != NULL)
326 return 1;
327 return 0;
328 }
329
setup_dp(X509 * x,DIST_POINT * dp)330 static void setup_dp(X509 *x, DIST_POINT *dp)
331 {
332 X509_NAME *iname = NULL;
333 size_t i;
334 if (dp->reasons)
335 {
336 if (dp->reasons->length > 0)
337 dp->dp_reasons = dp->reasons->data[0];
338 if (dp->reasons->length > 1)
339 dp->dp_reasons |= (dp->reasons->data[1] << 8);
340 dp->dp_reasons &= CRLDP_ALL_REASONS;
341 }
342 else
343 dp->dp_reasons = CRLDP_ALL_REASONS;
344 if (!dp->distpoint || (dp->distpoint->type != 1))
345 return;
346 for (i = 0; i < sk_GENERAL_NAME_num(dp->CRLissuer); i++)
347 {
348 GENERAL_NAME *gen = sk_GENERAL_NAME_value(dp->CRLissuer, i);
349 if (gen->type == GEN_DIRNAME)
350 {
351 iname = gen->d.directoryName;
352 break;
353 }
354 }
355 if (!iname)
356 iname = X509_get_issuer_name(x);
357
358 DIST_POINT_set_dpname(dp->distpoint, iname);
359
360 }
361
setup_crldp(X509 * x)362 static void setup_crldp(X509 *x)
363 {
364 size_t i;
365 x->crldp = X509_get_ext_d2i(x, NID_crl_distribution_points, NULL, NULL);
366 for (i = 0; i < sk_DIST_POINT_num(x->crldp); i++)
367 setup_dp(x, sk_DIST_POINT_value(x->crldp, i));
368 }
369
370 /* g_x509_cache_extensions_lock is used to protect against concurrent calls to
371 * |x509v3_cache_extensions|. Ideally this would be done with a |CRYPTO_once_t|
372 * in the |X509| structure, but |CRYPTO_once_t| isn't public.
373 *
374 * Note: it's not entirely clear whether this lock is needed. Not all paths to
375 * this function took a lock in OpenSSL. */
376 static struct CRYPTO_STATIC_MUTEX g_x509_cache_extensions_lock =
377 CRYPTO_STATIC_MUTEX_INIT;
378
x509v3_cache_extensions(X509 * x)379 static void x509v3_cache_extensions(X509 *x)
380 {
381 BASIC_CONSTRAINTS *bs;
382 PROXY_CERT_INFO_EXTENSION *pci;
383 ASN1_BIT_STRING *usage;
384 ASN1_BIT_STRING *ns;
385 EXTENDED_KEY_USAGE *extusage;
386 X509_EXTENSION *ex;
387 size_t i;
388 int j;
389
390 CRYPTO_STATIC_MUTEX_lock_write(&g_x509_cache_extensions_lock);
391
392 if(x->ex_flags & EXFLAG_SET)
393 {
394 CRYPTO_STATIC_MUTEX_unlock(&g_x509_cache_extensions_lock);
395 return;
396 }
397
398 X509_digest(x, EVP_sha1(), x->sha1_hash, NULL);
399 /* V1 should mean no extensions ... */
400 if(!X509_get_version(x)) x->ex_flags |= EXFLAG_V1;
401 /* Handle basic constraints */
402 if((bs=X509_get_ext_d2i(x, NID_basic_constraints, NULL, NULL))) {
403 if(bs->ca) x->ex_flags |= EXFLAG_CA;
404 if(bs->pathlen) {
405 if((bs->pathlen->type == V_ASN1_NEG_INTEGER)
406 || !bs->ca) {
407 x->ex_flags |= EXFLAG_INVALID;
408 x->ex_pathlen = 0;
409 } else x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen);
410 } else x->ex_pathlen = -1;
411 BASIC_CONSTRAINTS_free(bs);
412 x->ex_flags |= EXFLAG_BCONS;
413 }
414 /* Handle proxy certificates */
415 if((pci=X509_get_ext_d2i(x, NID_proxyCertInfo, NULL, NULL))) {
416 if (x->ex_flags & EXFLAG_CA
417 || X509_get_ext_by_NID(x, NID_subject_alt_name, -1) >= 0
418 || X509_get_ext_by_NID(x, NID_issuer_alt_name, -1) >= 0) {
419 x->ex_flags |= EXFLAG_INVALID;
420 }
421 if (pci->pcPathLengthConstraint) {
422 x->ex_pcpathlen =
423 ASN1_INTEGER_get(pci->pcPathLengthConstraint);
424 } else x->ex_pcpathlen = -1;
425 PROXY_CERT_INFO_EXTENSION_free(pci);
426 x->ex_flags |= EXFLAG_PROXY;
427 }
428 /* Handle key usage */
429 if((usage=X509_get_ext_d2i(x, NID_key_usage, NULL, NULL))) {
430 if(usage->length > 0) {
431 x->ex_kusage = usage->data[0];
432 if(usage->length > 1)
433 x->ex_kusage |= usage->data[1] << 8;
434 } else x->ex_kusage = 0;
435 x->ex_flags |= EXFLAG_KUSAGE;
436 ASN1_BIT_STRING_free(usage);
437 }
438 x->ex_xkusage = 0;
439 if((extusage=X509_get_ext_d2i(x, NID_ext_key_usage, NULL, NULL))) {
440 x->ex_flags |= EXFLAG_XKUSAGE;
441 for(i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) {
442 switch(OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage,i))) {
443 case NID_server_auth:
444 x->ex_xkusage |= XKU_SSL_SERVER;
445 break;
446
447 case NID_client_auth:
448 x->ex_xkusage |= XKU_SSL_CLIENT;
449 break;
450
451 case NID_email_protect:
452 x->ex_xkusage |= XKU_SMIME;
453 break;
454
455 case NID_code_sign:
456 x->ex_xkusage |= XKU_CODE_SIGN;
457 break;
458
459 case NID_ms_sgc:
460 case NID_ns_sgc:
461 x->ex_xkusage |= XKU_SGC;
462 break;
463
464 case NID_OCSP_sign:
465 x->ex_xkusage |= XKU_OCSP_SIGN;
466 break;
467
468 case NID_time_stamp:
469 x->ex_xkusage |= XKU_TIMESTAMP;
470 break;
471
472 case NID_dvcs:
473 x->ex_xkusage |= XKU_DVCS;
474 break;
475
476 case NID_anyExtendedKeyUsage:
477 x->ex_xkusage |= XKU_ANYEKU;
478 break;
479 }
480 }
481 sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free);
482 }
483
484 if((ns=X509_get_ext_d2i(x, NID_netscape_cert_type, NULL, NULL))) {
485 if(ns->length > 0) x->ex_nscert = ns->data[0];
486 else x->ex_nscert = 0;
487 x->ex_flags |= EXFLAG_NSCERT;
488 ASN1_BIT_STRING_free(ns);
489 }
490 x->skid =X509_get_ext_d2i(x, NID_subject_key_identifier, NULL, NULL);
491 x->akid =X509_get_ext_d2i(x, NID_authority_key_identifier, NULL, NULL);
492 /* Does subject name match issuer ? */
493 if(!X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x)))
494 {
495 x->ex_flags |= EXFLAG_SI;
496 /* If SKID matches AKID also indicate self signed */
497 if (X509_check_akid(x, x->akid) == X509_V_OK)
498 x->ex_flags |= EXFLAG_SS;
499 }
500 x->altname = X509_get_ext_d2i(x, NID_subject_alt_name, NULL, NULL);
501 x->nc = X509_get_ext_d2i(x, NID_name_constraints, &j, NULL);
502 if (!x->nc && (j != -1))
503 x->ex_flags |= EXFLAG_INVALID;
504 setup_crldp(x);
505
506 for (j = 0; j < X509_get_ext_count(x); j++)
507 {
508 ex = X509_get_ext(x, j);
509 if (OBJ_obj2nid(X509_EXTENSION_get_object(ex))
510 == NID_freshest_crl)
511 x->ex_flags |= EXFLAG_FRESHEST;
512 if (!X509_EXTENSION_get_critical(ex))
513 continue;
514 if (!X509_supported_extension(ex))
515 {
516 x->ex_flags |= EXFLAG_CRITICAL;
517 break;
518 }
519 }
520 x->ex_flags |= EXFLAG_SET;
521
522 CRYPTO_STATIC_MUTEX_unlock(&g_x509_cache_extensions_lock);
523 }
524
525 /* CA checks common to all purposes
526 * return codes:
527 * 0 not a CA
528 * 1 is a CA
529 * 2 basicConstraints absent so "maybe" a CA
530 * 3 basicConstraints absent but self signed V1.
531 * 4 basicConstraints absent but keyUsage present and keyCertSign asserted.
532 */
533
534 #define V1_ROOT (EXFLAG_V1|EXFLAG_SS)
535 #define ku_reject(x, usage) \
536 (((x)->ex_flags & EXFLAG_KUSAGE) && !((x)->ex_kusage & (usage)))
537 #define xku_reject(x, usage) \
538 (((x)->ex_flags & EXFLAG_XKUSAGE) && !((x)->ex_xkusage & (usage)))
539 #define ns_reject(x, usage) \
540 (((x)->ex_flags & EXFLAG_NSCERT) && !((x)->ex_nscert & (usage)))
541
check_ca(const X509 * x)542 static int check_ca(const X509 *x)
543 {
544 /* keyUsage if present should allow cert signing */
545 if(ku_reject(x, KU_KEY_CERT_SIGN)) return 0;
546 if(x->ex_flags & EXFLAG_BCONS) {
547 if(x->ex_flags & EXFLAG_CA) return 1;
548 /* If basicConstraints says not a CA then say so */
549 else return 0;
550 } else {
551 /* we support V1 roots for... uh, I don't really know why. */
552 if((x->ex_flags & V1_ROOT) == V1_ROOT) return 3;
553 /* If key usage present it must have certSign so tolerate it */
554 else if (x->ex_flags & EXFLAG_KUSAGE) return 4;
555 /* Older certificates could have Netscape-specific CA types */
556 else if (x->ex_flags & EXFLAG_NSCERT
557 && x->ex_nscert & NS_ANY_CA) return 5;
558 /* can this still be regarded a CA certificate? I doubt it */
559 return 0;
560 }
561 }
562
X509_check_ca(X509 * x)563 int X509_check_ca(X509 *x)
564 {
565 if(!(x->ex_flags & EXFLAG_SET)) {
566 x509v3_cache_extensions(x);
567 }
568
569 return check_ca(x);
570 }
571
572 /* Check SSL CA: common checks for SSL client and server */
check_ssl_ca(const X509 * x)573 static int check_ssl_ca(const X509 *x)
574 {
575 int ca_ret;
576 ca_ret = check_ca(x);
577 if(!ca_ret) return 0;
578 /* check nsCertType if present */
579 if(ca_ret != 5 || x->ex_nscert & NS_SSL_CA) return ca_ret;
580 else return 0;
581 }
582
583
check_purpose_ssl_client(const X509_PURPOSE * xp,const X509 * x,int ca)584 static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, int ca)
585 {
586 if(xku_reject(x,XKU_SSL_CLIENT)) return 0;
587 if(ca) return check_ssl_ca(x);
588 /* We need to do digital signatures or key agreement */
589 if(ku_reject(x,KU_DIGITAL_SIGNATURE|KU_KEY_AGREEMENT)) return 0;
590 /* nsCertType if present should allow SSL client use */
591 if(ns_reject(x, NS_SSL_CLIENT)) return 0;
592 return 1;
593 }
594 /* Key usage needed for TLS/SSL server: digital signature, encipherment or
595 * key agreement. The ssl code can check this more thoroughly for individual
596 * key types.
597 */
598 #define KU_TLS \
599 KU_DIGITAL_SIGNATURE|KU_KEY_ENCIPHERMENT|KU_KEY_AGREEMENT
600
check_purpose_ssl_server(const X509_PURPOSE * xp,const X509 * x,int ca)601 static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca)
602 {
603 if(xku_reject(x,XKU_SSL_SERVER|XKU_SGC)) return 0;
604 if(ca) return check_ssl_ca(x);
605
606 if(ns_reject(x, NS_SSL_SERVER)) return 0;
607 if(ku_reject(x, KU_TLS)) return 0;
608
609 return 1;
610
611 }
612
check_purpose_ns_ssl_server(const X509_PURPOSE * xp,const X509 * x,int ca)613 static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca)
614 {
615 int ret;
616 ret = check_purpose_ssl_server(xp, x, ca);
617 if(!ret || ca) return ret;
618 /* We need to encipher or Netscape complains */
619 if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0;
620 return ret;
621 }
622
623 /* common S/MIME checks */
purpose_smime(const X509 * x,int ca)624 static int purpose_smime(const X509 *x, int ca)
625 {
626 if(xku_reject(x,XKU_SMIME)) return 0;
627 if(ca) {
628 int ca_ret;
629 ca_ret = check_ca(x);
630 if(!ca_ret) return 0;
631 /* check nsCertType if present */
632 if(ca_ret != 5 || x->ex_nscert & NS_SMIME_CA) return ca_ret;
633 else return 0;
634 }
635 if(x->ex_flags & EXFLAG_NSCERT) {
636 if(x->ex_nscert & NS_SMIME) return 1;
637 /* Workaround for some buggy certificates */
638 if(x->ex_nscert & NS_SSL_CLIENT) return 2;
639 return 0;
640 }
641 return 1;
642 }
643
check_purpose_smime_sign(const X509_PURPOSE * xp,const X509 * x,int ca)644 static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, int ca)
645 {
646 int ret;
647 ret = purpose_smime(x, ca);
648 if(!ret || ca) return ret;
649 if(ku_reject(x, KU_DIGITAL_SIGNATURE|KU_NON_REPUDIATION)) return 0;
650 return ret;
651 }
652
check_purpose_smime_encrypt(const X509_PURPOSE * xp,const X509 * x,int ca)653 static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, int ca)
654 {
655 int ret;
656 ret = purpose_smime(x, ca);
657 if(!ret || ca) return ret;
658 if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0;
659 return ret;
660 }
661
check_purpose_crl_sign(const X509_PURPOSE * xp,const X509 * x,int ca)662 static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, int ca)
663 {
664 if(ca) {
665 int ca_ret;
666 if((ca_ret = check_ca(x)) != 2) return ca_ret;
667 else return 0;
668 }
669 if(ku_reject(x, KU_CRL_SIGN)) return 0;
670 return 1;
671 }
672
673 /* OCSP helper: this is *not* a full OCSP check. It just checks that
674 * each CA is valid. Additional checks must be made on the chain.
675 */
676
ocsp_helper(const X509_PURPOSE * xp,const X509 * x,int ca)677 static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca)
678 {
679 /* Must be a valid CA. Should we really support the "I don't know"
680 value (2)? */
681 if(ca) return check_ca(x);
682 /* leaf certificate is checked in OCSP_verify() */
683 return 1;
684 }
685
check_purpose_timestamp_sign(const X509_PURPOSE * xp,const X509 * x,int ca)686 static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x,
687 int ca)
688 {
689 int i_ext;
690
691 /* If ca is true we must return if this is a valid CA certificate. */
692 if (ca) return check_ca(x);
693
694 /*
695 * Check the optional key usage field:
696 * if Key Usage is present, it must be one of digitalSignature
697 * and/or nonRepudiation (other values are not consistent and shall
698 * be rejected).
699 */
700 if ((x->ex_flags & EXFLAG_KUSAGE)
701 && ((x->ex_kusage & ~(KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE)) ||
702 !(x->ex_kusage & (KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE))))
703 return 0;
704
705 /* Only time stamp key usage is permitted and it's required. */
706 if (!(x->ex_flags & EXFLAG_XKUSAGE) || x->ex_xkusage != XKU_TIMESTAMP)
707 return 0;
708
709 /* Extended Key Usage MUST be critical */
710 i_ext = X509_get_ext_by_NID((X509 *) x, NID_ext_key_usage, -1);
711 if (i_ext >= 0)
712 {
713 X509_EXTENSION *ext = X509_get_ext((X509 *) x, i_ext);
714 if (!X509_EXTENSION_get_critical(ext))
715 return 0;
716 }
717
718 return 1;
719 }
720
no_check(const X509_PURPOSE * xp,const X509 * x,int ca)721 static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca)
722 {
723 return 1;
724 }
725
726 /* Various checks to see if one certificate issued the second.
727 * This can be used to prune a set of possible issuer certificates
728 * which have been looked up using some simple method such as by
729 * subject name.
730 * These are:
731 * 1. Check issuer_name(subject) == subject_name(issuer)
732 * 2. If akid(subject) exists check it matches issuer
733 * 3. If key_usage(issuer) exists check it supports certificate signing
734 * returns 0 for OK, positive for reason for mismatch, reasons match
735 * codes for X509_verify_cert()
736 */
737
X509_check_issued(X509 * issuer,X509 * subject)738 int X509_check_issued(X509 *issuer, X509 *subject)
739 {
740 if(X509_NAME_cmp(X509_get_subject_name(issuer),
741 X509_get_issuer_name(subject)))
742 return X509_V_ERR_SUBJECT_ISSUER_MISMATCH;
743 x509v3_cache_extensions(issuer);
744 x509v3_cache_extensions(subject);
745
746 if(subject->akid)
747 {
748 int ret = X509_check_akid(issuer, subject->akid);
749 if (ret != X509_V_OK)
750 return ret;
751 }
752
753 if(subject->ex_flags & EXFLAG_PROXY)
754 {
755 if(ku_reject(issuer, KU_DIGITAL_SIGNATURE))
756 return X509_V_ERR_KEYUSAGE_NO_DIGITAL_SIGNATURE;
757 }
758 else if(ku_reject(issuer, KU_KEY_CERT_SIGN))
759 return X509_V_ERR_KEYUSAGE_NO_CERTSIGN;
760 return X509_V_OK;
761 }
762
X509_check_akid(X509 * issuer,AUTHORITY_KEYID * akid)763 int X509_check_akid(X509 *issuer, AUTHORITY_KEYID *akid)
764 {
765
766 if(!akid)
767 return X509_V_OK;
768
769 /* Check key ids (if present) */
770 if(akid->keyid && issuer->skid &&
771 ASN1_OCTET_STRING_cmp(akid->keyid, issuer->skid) )
772 return X509_V_ERR_AKID_SKID_MISMATCH;
773 /* Check serial number */
774 if(akid->serial &&
775 ASN1_INTEGER_cmp(X509_get_serialNumber(issuer), akid->serial))
776 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH;
777 /* Check issuer name */
778 if(akid->issuer)
779 {
780 /* Ugh, for some peculiar reason AKID includes
781 * SEQUENCE OF GeneralName. So look for a DirName.
782 * There may be more than one but we only take any
783 * notice of the first.
784 */
785 GENERAL_NAMES *gens;
786 GENERAL_NAME *gen;
787 X509_NAME *nm = NULL;
788 size_t i;
789 gens = akid->issuer;
790 for(i = 0; i < sk_GENERAL_NAME_num(gens); i++)
791 {
792 gen = sk_GENERAL_NAME_value(gens, i);
793 if(gen->type == GEN_DIRNAME)
794 {
795 nm = gen->d.dirn;
796 break;
797 }
798 }
799 if(nm && X509_NAME_cmp(nm, X509_get_issuer_name(issuer)))
800 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH;
801 }
802 return X509_V_OK;
803 }
804
805