1/* v3_purp.c */ 2/* 3 * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL project 4 * 2001. 5 */ 6/* ==================================================================== 7 * Copyright (c) 1999-2004 The OpenSSL Project. All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in 18 * the documentation and/or other materials provided with the 19 * distribution. 20 * 21 * 3. All advertising materials mentioning features or use of this 22 * software must display the following acknowledgment: 23 * "This product includes software developed by the OpenSSL Project 24 * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)" 25 * 26 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to 27 * endorse or promote products derived from this software without 28 * prior written permission. For written permission, please contact 29 * licensing@OpenSSL.org. 30 * 31 * 5. Products derived from this software may not be called "OpenSSL" 32 * nor may "OpenSSL" appear in their names without prior written 33 * permission of the OpenSSL Project. 34 * 35 * 6. Redistributions of any form whatsoever must retain the following 36 * acknowledgment: 37 * "This product includes software developed by the OpenSSL Project 38 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)" 39 * 40 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY 41 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 43 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR 44 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 45 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 46 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 47 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 49 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 50 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 51 * OF THE POSSIBILITY OF SUCH DAMAGE. 52 * ==================================================================== 53 * 54 * This product includes cryptographic software written by Eric Young 55 * (eay@cryptsoft.com). This product includes software written by Tim 56 * Hudson (tjh@cryptsoft.com). 57 * 58 */ 59 60#include <stdio.h> 61#include "cryptlib.h" 62#include <openssl/x509v3.h> 63#include <openssl/x509_vfy.h> 64 65static void x509v3_cache_extensions(X509 *x); 66 67static int check_ssl_ca(const X509 *x); 68static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, 69 int ca); 70static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, 71 int ca); 72static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, 73 int ca); 74static int purpose_smime(const X509 *x, int ca); 75static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, 76 int ca); 77static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, 78 int ca); 79static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, 80 int ca); 81static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x, 82 int ca); 83static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca); 84static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca); 85 86static int xp_cmp(const X509_PURPOSE *const *a, const X509_PURPOSE *const *b); 87static void xptable_free(X509_PURPOSE *p); 88 89static 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 113IMPLEMENT_STACK_OF(X509_PURPOSE) 114 115static STACK_OF(X509_PURPOSE) *xptable = NULL; 116 117static 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 */ 127int X509_check_purpose(X509 *x, int id, int ca) 128{ 129 int idx; 130 const X509_PURPOSE *pt; 131 if (!(x->ex_flags & EXFLAG_SET)) { 132 CRYPTO_w_lock(CRYPTO_LOCK_X509); 133 x509v3_cache_extensions(x); 134 CRYPTO_w_unlock(CRYPTO_LOCK_X509); 135 } 136 if (id == -1) 137 return 1; 138 idx = X509_PURPOSE_get_by_id(id); 139 if (idx == -1) 140 return -1; 141 pt = X509_PURPOSE_get0(idx); 142 return pt->check_purpose(pt, x, ca); 143} 144 145int X509_PURPOSE_set(int *p, int purpose) 146{ 147 if (X509_PURPOSE_get_by_id(purpose) == -1) { 148 X509V3err(X509V3_F_X509_PURPOSE_SET, X509V3_R_INVALID_PURPOSE); 149 return 0; 150 } 151 *p = purpose; 152 return 1; 153} 154 155int X509_PURPOSE_get_count(void) 156{ 157 if (!xptable) 158 return X509_PURPOSE_COUNT; 159 return sk_X509_PURPOSE_num(xptable) + X509_PURPOSE_COUNT; 160} 161 162X509_PURPOSE *X509_PURPOSE_get0(int idx) 163{ 164 if (idx < 0) 165 return NULL; 166 if (idx < (int)X509_PURPOSE_COUNT) 167 return xstandard + idx; 168 return sk_X509_PURPOSE_value(xptable, idx - X509_PURPOSE_COUNT); 169} 170 171int X509_PURPOSE_get_by_sname(char *sname) 172{ 173 int i; 174 X509_PURPOSE *xptmp; 175 for (i = 0; i < X509_PURPOSE_get_count(); i++) { 176 xptmp = X509_PURPOSE_get0(i); 177 if (!strcmp(xptmp->sname, sname)) 178 return i; 179 } 180 return -1; 181} 182 183int X509_PURPOSE_get_by_id(int purpose) 184{ 185 X509_PURPOSE tmp; 186 int idx; 187 if ((purpose >= X509_PURPOSE_MIN) && (purpose <= X509_PURPOSE_MAX)) 188 return purpose - X509_PURPOSE_MIN; 189 tmp.purpose = purpose; 190 if (!xptable) 191 return -1; 192 idx = sk_X509_PURPOSE_find(xptable, &tmp); 193 if (idx == -1) 194 return -1; 195 return idx + X509_PURPOSE_COUNT; 196} 197 198int X509_PURPOSE_add(int id, int trust, int flags, 199 int (*ck) (const X509_PURPOSE *, const X509 *, int), 200 char *name, char *sname, void *arg) 201{ 202 int idx; 203 X509_PURPOSE *ptmp; 204 /* 205 * This is set according to what we change: application can't set it 206 */ 207 flags &= ~X509_PURPOSE_DYNAMIC; 208 /* This will always be set for application modified trust entries */ 209 flags |= X509_PURPOSE_DYNAMIC_NAME; 210 /* Get existing entry if any */ 211 idx = X509_PURPOSE_get_by_id(id); 212 /* Need a new entry */ 213 if (idx == -1) { 214 if (!(ptmp = OPENSSL_malloc(sizeof(X509_PURPOSE)))) { 215 X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE); 216 return 0; 217 } 218 ptmp->flags = X509_PURPOSE_DYNAMIC; 219 } else 220 ptmp = X509_PURPOSE_get0(idx); 221 222 /* OPENSSL_free existing name if dynamic */ 223 if (ptmp->flags & X509_PURPOSE_DYNAMIC_NAME) { 224 OPENSSL_free(ptmp->name); 225 OPENSSL_free(ptmp->sname); 226 } 227 /* dup supplied name */ 228 ptmp->name = BUF_strdup(name); 229 ptmp->sname = BUF_strdup(sname); 230 if (!ptmp->name || !ptmp->sname) { 231 X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE); 232 return 0; 233 } 234 /* Keep the dynamic flag of existing entry */ 235 ptmp->flags &= X509_PURPOSE_DYNAMIC; 236 /* Set all other flags */ 237 ptmp->flags |= flags; 238 239 ptmp->purpose = id; 240 ptmp->trust = trust; 241 ptmp->check_purpose = ck; 242 ptmp->usr_data = arg; 243 244 /* If its a new entry manage the dynamic table */ 245 if (idx == -1) { 246 if (!xptable && !(xptable = sk_X509_PURPOSE_new(xp_cmp))) { 247 X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE); 248 return 0; 249 } 250 if (!sk_X509_PURPOSE_push(xptable, ptmp)) { 251 X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE); 252 return 0; 253 } 254 } 255 return 1; 256} 257 258static void xptable_free(X509_PURPOSE *p) 259{ 260 if (!p) 261 return; 262 if (p->flags & X509_PURPOSE_DYNAMIC) { 263 if (p->flags & X509_PURPOSE_DYNAMIC_NAME) { 264 OPENSSL_free(p->name); 265 OPENSSL_free(p->sname); 266 } 267 OPENSSL_free(p); 268 } 269} 270 271void X509_PURPOSE_cleanup(void) 272{ 273 unsigned int i; 274 sk_X509_PURPOSE_pop_free(xptable, xptable_free); 275 for (i = 0; i < X509_PURPOSE_COUNT; i++) 276 xptable_free(xstandard + i); 277 xptable = NULL; 278} 279 280int X509_PURPOSE_get_id(X509_PURPOSE *xp) 281{ 282 return xp->purpose; 283} 284 285char *X509_PURPOSE_get0_name(X509_PURPOSE *xp) 286{ 287 return xp->name; 288} 289 290char *X509_PURPOSE_get0_sname(X509_PURPOSE *xp) 291{ 292 return xp->sname; 293} 294 295int X509_PURPOSE_get_trust(X509_PURPOSE *xp) 296{ 297 return xp->trust; 298} 299 300static int nid_cmp(const int *a, const int *b) 301{ 302 return *a - *b; 303} 304 305DECLARE_OBJ_BSEARCH_CMP_FN(int, int, nid); 306IMPLEMENT_OBJ_BSEARCH_CMP_FN(int, int, nid); 307 308int X509_supported_extension(X509_EXTENSION *ex) 309{ 310 /* 311 * This table is a list of the NIDs of supported extensions: that is 312 * those which are used by the verify process. If an extension is 313 * critical and doesn't appear in this list then the verify process will 314 * normally reject the certificate. The list must be kept in numerical 315 * order because it will be searched using bsearch. 316 */ 317 318 static const int supported_nids[] = { 319 NID_netscape_cert_type, /* 71 */ 320 NID_key_usage, /* 83 */ 321 NID_subject_alt_name, /* 85 */ 322 NID_basic_constraints, /* 87 */ 323 NID_certificate_policies, /* 89 */ 324 NID_ext_key_usage, /* 126 */ 325#ifndef OPENSSL_NO_RFC3779 326 NID_sbgp_ipAddrBlock, /* 290 */ 327 NID_sbgp_autonomousSysNum, /* 291 */ 328#endif 329 NID_policy_constraints, /* 401 */ 330 NID_proxyCertInfo, /* 663 */ 331 NID_name_constraints, /* 666 */ 332 NID_policy_mappings, /* 747 */ 333 NID_inhibit_any_policy /* 748 */ 334 }; 335 336 int ex_nid = OBJ_obj2nid(X509_EXTENSION_get_object(ex)); 337 338 if (ex_nid == NID_undef) 339 return 0; 340 341 if (OBJ_bsearch_nid(&ex_nid, supported_nids, 342 sizeof(supported_nids) / sizeof(int))) 343 return 1; 344 return 0; 345} 346 347static 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 375static 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 391static 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; 399 400 int i; 401 if (x->ex_flags & EXFLAG_SET) 402 return; 403#ifndef OPENSSL_NO_SHA 404 X509_digest(x, EVP_sha1(), x->sha1_hash, NULL); 405#endif 406 /* V1 should mean no extensions ... */ 407 if (!X509_get_version(x)) 408 x->ex_flags |= EXFLAG_V1; 409 /* Handle basic constraints */ 410 if ((bs = X509_get_ext_d2i(x, NID_basic_constraints, NULL, NULL))) { 411 if (bs->ca) 412 x->ex_flags |= EXFLAG_CA; 413 if (bs->pathlen) { 414 if ((bs->pathlen->type == V_ASN1_NEG_INTEGER) 415 || !bs->ca) { 416 x->ex_flags |= EXFLAG_INVALID; 417 x->ex_pathlen = 0; 418 } else 419 x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen); 420 } else 421 x->ex_pathlen = -1; 422 BASIC_CONSTRAINTS_free(bs); 423 x->ex_flags |= EXFLAG_BCONS; 424 } 425 /* Handle proxy certificates */ 426 if ((pci = X509_get_ext_d2i(x, NID_proxyCertInfo, NULL, NULL))) { 427 if (x->ex_flags & EXFLAG_CA 428 || X509_get_ext_by_NID(x, NID_subject_alt_name, -1) >= 0 429 || X509_get_ext_by_NID(x, NID_issuer_alt_name, -1) >= 0) { 430 x->ex_flags |= EXFLAG_INVALID; 431 } 432 if (pci->pcPathLengthConstraint) { 433 x->ex_pcpathlen = ASN1_INTEGER_get(pci->pcPathLengthConstraint); 434 } else 435 x->ex_pcpathlen = -1; 436 PROXY_CERT_INFO_EXTENSION_free(pci); 437 x->ex_flags |= EXFLAG_PROXY; 438 } 439 /* Handle key usage */ 440 if ((usage = X509_get_ext_d2i(x, NID_key_usage, NULL, NULL))) { 441 if (usage->length > 0) { 442 x->ex_kusage = usage->data[0]; 443 if (usage->length > 1) 444 x->ex_kusage |= usage->data[1] << 8; 445 } else 446 x->ex_kusage = 0; 447 x->ex_flags |= EXFLAG_KUSAGE; 448 ASN1_BIT_STRING_free(usage); 449 } 450 x->ex_xkusage = 0; 451 if ((extusage = X509_get_ext_d2i(x, NID_ext_key_usage, NULL, NULL))) { 452 x->ex_flags |= EXFLAG_XKUSAGE; 453 for (i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) { 454 switch (OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage, i))) { 455 case NID_server_auth: 456 x->ex_xkusage |= XKU_SSL_SERVER; 457 break; 458 459 case NID_client_auth: 460 x->ex_xkusage |= XKU_SSL_CLIENT; 461 break; 462 463 case NID_email_protect: 464 x->ex_xkusage |= XKU_SMIME; 465 break; 466 467 case NID_code_sign: 468 x->ex_xkusage |= XKU_CODE_SIGN; 469 break; 470 471 case NID_ms_sgc: 472 case NID_ns_sgc: 473 x->ex_xkusage |= XKU_SGC; 474 break; 475 476 case NID_OCSP_sign: 477 x->ex_xkusage |= XKU_OCSP_SIGN; 478 break; 479 480 case NID_time_stamp: 481 x->ex_xkusage |= XKU_TIMESTAMP; 482 break; 483 484 case NID_dvcs: 485 x->ex_xkusage |= XKU_DVCS; 486 break; 487 488 case NID_anyExtendedKeyUsage: 489 x->ex_xkusage |= XKU_ANYEKU; 490 break; 491 } 492 } 493 sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free); 494 } 495 496 if ((ns = X509_get_ext_d2i(x, NID_netscape_cert_type, NULL, NULL))) { 497 if (ns->length > 0) 498 x->ex_nscert = ns->data[0]; 499 else 500 x->ex_nscert = 0; 501 x->ex_flags |= EXFLAG_NSCERT; 502 ASN1_BIT_STRING_free(ns); 503 } 504 x->skid = X509_get_ext_d2i(x, NID_subject_key_identifier, NULL, NULL); 505 x->akid = X509_get_ext_d2i(x, NID_authority_key_identifier, NULL, NULL); 506 /* Does subject name match issuer ? */ 507 if (!X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x))) { 508 x->ex_flags |= EXFLAG_SI; 509 /* If SKID matches AKID also indicate self signed */ 510 if (X509_check_akid(x, x->akid) == X509_V_OK && 511 !ku_reject(x, KU_KEY_CERT_SIGN)) 512 x->ex_flags |= EXFLAG_SS; 513 } 514 x->altname = X509_get_ext_d2i(x, NID_subject_alt_name, NULL, NULL); 515 x->nc = X509_get_ext_d2i(x, NID_name_constraints, &i, NULL); 516 if (!x->nc && (i != -1)) 517 x->ex_flags |= EXFLAG_INVALID; 518 setup_crldp(x); 519 520#ifndef OPENSSL_NO_RFC3779 521 x->rfc3779_addr = X509_get_ext_d2i(x, NID_sbgp_ipAddrBlock, NULL, NULL); 522 x->rfc3779_asid = X509_get_ext_d2i(x, NID_sbgp_autonomousSysNum, 523 NULL, NULL); 524#endif 525 for (i = 0; i < X509_get_ext_count(x); i++) { 526 ex = X509_get_ext(x, i); 527 if (OBJ_obj2nid(X509_EXTENSION_get_object(ex)) 528 == NID_freshest_crl) 529 x->ex_flags |= EXFLAG_FRESHEST; 530 if (!X509_EXTENSION_get_critical(ex)) 531 continue; 532 if (!X509_supported_extension(ex)) { 533 x->ex_flags |= EXFLAG_CRITICAL; 534 break; 535 } 536 } 537 x->ex_flags |= EXFLAG_SET; 538} 539 540/*- 541 * CA checks common to all purposes 542 * return codes: 543 * 0 not a CA 544 * 1 is a CA 545 * 2 basicConstraints absent so "maybe" a CA 546 * 3 basicConstraints absent but self signed V1. 547 * 4 basicConstraints absent but keyUsage present and keyCertSign asserted. 548 */ 549 550static int check_ca(const X509 *x) 551{ 552 /* keyUsage if present should allow cert signing */ 553 if (ku_reject(x, KU_KEY_CERT_SIGN)) 554 return 0; 555 if (x->ex_flags & EXFLAG_BCONS) { 556 if (x->ex_flags & EXFLAG_CA) 557 return 1; 558 /* If basicConstraints says not a CA then say so */ 559 else 560 return 0; 561 } else { 562 /* we support V1 roots for... uh, I don't really know why. */ 563 if ((x->ex_flags & V1_ROOT) == V1_ROOT) 564 return 3; 565 /* 566 * If key usage present it must have certSign so tolerate it 567 */ 568 else if (x->ex_flags & EXFLAG_KUSAGE) 569 return 4; 570 /* Older certificates could have Netscape-specific CA types */ 571 else if (x->ex_flags & EXFLAG_NSCERT && x->ex_nscert & NS_ANY_CA) 572 return 5; 573 /* can this still be regarded a CA certificate? I doubt it */ 574 return 0; 575 } 576} 577 578int X509_check_ca(X509 *x) 579{ 580 if (!(x->ex_flags & EXFLAG_SET)) { 581 CRYPTO_w_lock(CRYPTO_LOCK_X509); 582 x509v3_cache_extensions(x); 583 CRYPTO_w_unlock(CRYPTO_LOCK_X509); 584 } 585 586 return check_ca(x); 587} 588 589/* Check SSL CA: common checks for SSL client and server */ 590static int check_ssl_ca(const X509 *x) 591{ 592 int ca_ret; 593 ca_ret = check_ca(x); 594 if (!ca_ret) 595 return 0; 596 /* check nsCertType if present */ 597 if (ca_ret != 5 || x->ex_nscert & NS_SSL_CA) 598 return ca_ret; 599 else 600 return 0; 601} 602 603static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, 604 int ca) 605{ 606 if (xku_reject(x, XKU_SSL_CLIENT)) 607 return 0; 608 if (ca) 609 return check_ssl_ca(x); 610 /* We need to do digital signatures or key agreement */ 611 if (ku_reject(x, KU_DIGITAL_SIGNATURE | KU_KEY_AGREEMENT)) 612 return 0; 613 /* nsCertType if present should allow SSL client use */ 614 if (ns_reject(x, NS_SSL_CLIENT)) 615 return 0; 616 return 1; 617} 618 619/* 620 * Key usage needed for TLS/SSL server: digital signature, encipherment or 621 * key agreement. The ssl code can check this more thoroughly for individual 622 * key types. 623 */ 624#define KU_TLS \ 625 KU_DIGITAL_SIGNATURE|KU_KEY_ENCIPHERMENT|KU_KEY_AGREEMENT 626 627static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, 628 int ca) 629{ 630 if (xku_reject(x, XKU_SSL_SERVER | XKU_SGC)) 631 return 0; 632 if (ca) 633 return check_ssl_ca(x); 634 635 if (ns_reject(x, NS_SSL_SERVER)) 636 return 0; 637 if (ku_reject(x, KU_TLS)) 638 return 0; 639 640 return 1; 641 642} 643 644static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, 645 int ca) 646{ 647 int ret; 648 ret = check_purpose_ssl_server(xp, x, ca); 649 if (!ret || ca) 650 return ret; 651 /* We need to encipher or Netscape complains */ 652 if (ku_reject(x, KU_KEY_ENCIPHERMENT)) 653 return 0; 654 return ret; 655} 656 657/* common S/MIME checks */ 658static int purpose_smime(const X509 *x, int ca) 659{ 660 if (xku_reject(x, XKU_SMIME)) 661 return 0; 662 if (ca) { 663 int ca_ret; 664 ca_ret = check_ca(x); 665 if (!ca_ret) 666 return 0; 667 /* check nsCertType if present */ 668 if (ca_ret != 5 || x->ex_nscert & NS_SMIME_CA) 669 return ca_ret; 670 else 671 return 0; 672 } 673 if (x->ex_flags & EXFLAG_NSCERT) { 674 if (x->ex_nscert & NS_SMIME) 675 return 1; 676 /* Workaround for some buggy certificates */ 677 if (x->ex_nscert & NS_SSL_CLIENT) 678 return 2; 679 return 0; 680 } 681 return 1; 682} 683 684static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, 685 int ca) 686{ 687 int ret; 688 ret = purpose_smime(x, ca); 689 if (!ret || ca) 690 return ret; 691 if (ku_reject(x, KU_DIGITAL_SIGNATURE | KU_NON_REPUDIATION)) 692 return 0; 693 return ret; 694} 695 696static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, 697 int ca) 698{ 699 int ret; 700 ret = purpose_smime(x, ca); 701 if (!ret || ca) 702 return ret; 703 if (ku_reject(x, KU_KEY_ENCIPHERMENT)) 704 return 0; 705 return ret; 706} 707 708static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, 709 int ca) 710{ 711 if (ca) { 712 int ca_ret; 713 if ((ca_ret = check_ca(x)) != 2) 714 return ca_ret; 715 else 716 return 0; 717 } 718 if (ku_reject(x, KU_CRL_SIGN)) 719 return 0; 720 return 1; 721} 722 723/* 724 * OCSP helper: this is *not* a full OCSP check. It just checks that each CA 725 * is valid. Additional checks must be made on the chain. 726 */ 727 728static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca) 729{ 730 /* 731 * Must be a valid CA. Should we really support the "I don't know" value 732 * (2)? 733 */ 734 if (ca) 735 return check_ca(x); 736 /* leaf certificate is checked in OCSP_verify() */ 737 return 1; 738} 739 740static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x, 741 int ca) 742{ 743 int i_ext; 744 745 /* If ca is true we must return if this is a valid CA certificate. */ 746 if (ca) 747 return check_ca(x); 748 749 /* 750 * Check the optional key usage field: 751 * if Key Usage is present, it must be one of digitalSignature 752 * and/or nonRepudiation (other values are not consistent and shall 753 * be rejected). 754 */ 755 if ((x->ex_flags & EXFLAG_KUSAGE) 756 && ((x->ex_kusage & ~(KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE)) || 757 !(x->ex_kusage & (KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE)))) 758 return 0; 759 760 /* Only time stamp key usage is permitted and it's required. */ 761 if (!(x->ex_flags & EXFLAG_XKUSAGE) || x->ex_xkusage != XKU_TIMESTAMP) 762 return 0; 763 764 /* Extended Key Usage MUST be critical */ 765 i_ext = X509_get_ext_by_NID((X509 *)x, NID_ext_key_usage, -1); 766 if (i_ext >= 0) { 767 X509_EXTENSION *ext = X509_get_ext((X509 *)x, i_ext); 768 if (!X509_EXTENSION_get_critical(ext)) 769 return 0; 770 } 771 772 return 1; 773} 774 775static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca) 776{ 777 return 1; 778} 779 780/*- 781 * Various checks to see if one certificate issued the second. 782 * This can be used to prune a set of possible issuer certificates 783 * which have been looked up using some simple method such as by 784 * subject name. 785 * These are: 786 * 1. Check issuer_name(subject) == subject_name(issuer) 787 * 2. If akid(subject) exists check it matches issuer 788 * 3. If key_usage(issuer) exists check it supports certificate signing 789 * returns 0 for OK, positive for reason for mismatch, reasons match 790 * codes for X509_verify_cert() 791 */ 792 793int X509_check_issued(X509 *issuer, X509 *subject) 794{ 795 if (X509_NAME_cmp(X509_get_subject_name(issuer), 796 X509_get_issuer_name(subject))) 797 return X509_V_ERR_SUBJECT_ISSUER_MISMATCH; 798 x509v3_cache_extensions(issuer); 799 x509v3_cache_extensions(subject); 800 801 if (subject->akid) { 802 int ret = X509_check_akid(issuer, subject->akid); 803 if (ret != X509_V_OK) 804 return ret; 805 } 806 807 if (subject->ex_flags & EXFLAG_PROXY) { 808 if (ku_reject(issuer, KU_DIGITAL_SIGNATURE)) 809 return X509_V_ERR_KEYUSAGE_NO_DIGITAL_SIGNATURE; 810 } else if (ku_reject(issuer, KU_KEY_CERT_SIGN)) 811 return X509_V_ERR_KEYUSAGE_NO_CERTSIGN; 812 return X509_V_OK; 813} 814 815int X509_check_akid(X509 *issuer, AUTHORITY_KEYID *akid) 816{ 817 818 if (!akid) 819 return X509_V_OK; 820 821 /* Check key ids (if present) */ 822 if (akid->keyid && issuer->skid && 823 ASN1_OCTET_STRING_cmp(akid->keyid, issuer->skid)) 824 return X509_V_ERR_AKID_SKID_MISMATCH; 825 /* Check serial number */ 826 if (akid->serial && 827 ASN1_INTEGER_cmp(X509_get_serialNumber(issuer), akid->serial)) 828 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH; 829 /* Check issuer name */ 830 if (akid->issuer) { 831 /* 832 * Ugh, for some peculiar reason AKID includes SEQUENCE OF 833 * GeneralName. So look for a DirName. There may be more than one but 834 * we only take any notice of the first. 835 */ 836 GENERAL_NAMES *gens; 837 GENERAL_NAME *gen; 838 X509_NAME *nm = NULL; 839 int i; 840 gens = akid->issuer; 841 for (i = 0; i < sk_GENERAL_NAME_num(gens); i++) { 842 gen = sk_GENERAL_NAME_value(gens, i); 843 if (gen->type == GEN_DIRNAME) { 844 nm = gen->d.dirn; 845 break; 846 } 847 } 848 if (nm && X509_NAME_cmp(nm, X509_get_issuer_name(issuer))) 849 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH; 850 } 851 return X509_V_OK; 852} 853