1 /* $OpenBSD: x509_purp.c,v 1.41 2024/04/09 15:00:44 tb Exp $ */ 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 */ 58 59 #include <stdio.h> 60 #include <string.h> 61 62 #include <openssl/opensslconf.h> 63 64 #include <openssl/err.h> 65 #include <openssl/x509v3.h> 66 #include <openssl/x509_vfy.h> 67 68 #include "x509_internal.h" 69 #include "x509_local.h" 70 71 struct x509_purpose_st { 72 int purpose; 73 int trust; /* Default trust ID */ 74 int flags; 75 int (*check_purpose)(const struct x509_purpose_st *, const X509 *, int); 76 char *name; 77 char *sname; 78 void *usr_data; 79 } /* X509_PURPOSE */; 80 81 #define V1_ROOT (EXFLAG_V1|EXFLAG_SS) 82 #define ku_reject(x, usage) \ 83 (((x)->ex_flags & EXFLAG_KUSAGE) && !((x)->ex_kusage & (usage))) 84 #define xku_reject(x, usage) \ 85 (((x)->ex_flags & EXFLAG_XKUSAGE) && !((x)->ex_xkusage & (usage))) 86 #define ns_reject(x, usage) \ 87 (((x)->ex_flags & EXFLAG_NSCERT) && !((x)->ex_nscert & (usage))) 88 89 static int check_ssl_ca(const X509 *x); 90 static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, 91 int ca); 92 static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, 93 int ca); 94 static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, 95 int ca); 96 static int purpose_smime(const X509 *x, int ca); 97 static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, 98 int ca); 99 static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, 100 int ca); 101 static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, 102 int ca); 103 static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x, 104 int ca); 105 static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca); 106 static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca); 107 108 static const X509_PURPOSE xstandard[] = { 109 { 110 .purpose = X509_PURPOSE_SSL_CLIENT, 111 .trust = X509_TRUST_SSL_CLIENT, 112 .check_purpose = check_purpose_ssl_client, 113 .name = "SSL client", 114 .sname = "sslclient", 115 }, 116 { 117 .purpose = X509_PURPOSE_SSL_SERVER, 118 .trust = X509_TRUST_SSL_SERVER, 119 .check_purpose = check_purpose_ssl_server, 120 .name = "SSL server", 121 .sname = "sslserver", 122 }, 123 { 124 .purpose = X509_PURPOSE_NS_SSL_SERVER, 125 .trust = X509_TRUST_SSL_SERVER, 126 .check_purpose = check_purpose_ns_ssl_server, 127 .name = "Netscape SSL server", 128 .sname = "nssslserver", 129 }, 130 { 131 .purpose = X509_PURPOSE_SMIME_SIGN, 132 .trust = X509_TRUST_EMAIL, 133 .check_purpose = check_purpose_smime_sign, 134 .name = "S/MIME signing", 135 .sname = "smimesign", 136 }, 137 { 138 .purpose = X509_PURPOSE_SMIME_ENCRYPT, 139 .trust = X509_TRUST_EMAIL, 140 .check_purpose = check_purpose_smime_encrypt, 141 .name = "S/MIME encryption", 142 .sname = "smimeencrypt", 143 }, 144 { 145 .purpose = X509_PURPOSE_CRL_SIGN, 146 .trust = X509_TRUST_COMPAT, 147 .check_purpose = check_purpose_crl_sign, 148 .name = "CRL signing", 149 .sname = "crlsign", 150 }, 151 { 152 .purpose = X509_PURPOSE_ANY, 153 .trust = X509_TRUST_DEFAULT, 154 .check_purpose = no_check, 155 .name = "Any Purpose", 156 .sname = "any", 157 }, 158 { 159 .purpose = X509_PURPOSE_OCSP_HELPER, 160 .trust = X509_TRUST_COMPAT, 161 .check_purpose = ocsp_helper, 162 .name = "OCSP helper", 163 .sname = "ocsphelper", 164 }, 165 { 166 .purpose = X509_PURPOSE_TIMESTAMP_SIGN, 167 .trust = X509_TRUST_TSA, 168 .check_purpose = check_purpose_timestamp_sign, 169 .name = "Time Stamp signing", 170 .sname = "timestampsign", 171 }, 172 }; 173 174 #define X509_PURPOSE_COUNT (sizeof(xstandard) / sizeof(xstandard[0])) 175 176 /* As much as I'd like to make X509_check_purpose use a "const" X509* 177 * I really can't because it does recalculate hashes and do other non-const 178 * things. */ 179 int 180 X509_check_purpose(X509 *x, int id, int ca) 181 { 182 int idx; 183 const X509_PURPOSE *pt; 184 185 if (!x509v3_cache_extensions(x)) 186 return -1; 187 188 if (id == -1) 189 return 1; 190 191 if ((idx = X509_PURPOSE_get_by_id(id)) == -1) 192 return -1; 193 if ((pt = X509_PURPOSE_get0(idx)) == NULL) 194 return -1; 195 196 return pt->check_purpose(pt, x, ca); 197 } 198 LCRYPTO_ALIAS(X509_check_purpose); 199 200 int 201 X509_PURPOSE_get_count(void) 202 { 203 return X509_PURPOSE_COUNT; 204 } 205 LCRYPTO_ALIAS(X509_PURPOSE_get_count); 206 207 const X509_PURPOSE * 208 X509_PURPOSE_get0(int idx) 209 { 210 if (idx < 0 || (size_t)idx >= X509_PURPOSE_COUNT) 211 return NULL; 212 213 return &xstandard[idx]; 214 } 215 LCRYPTO_ALIAS(X509_PURPOSE_get0); 216 217 int 218 X509_PURPOSE_get_by_sname(const char *sname) 219 { 220 int i; 221 const X509_PURPOSE *xptmp; 222 223 for (i = 0; i < X509_PURPOSE_get_count(); i++) { 224 xptmp = X509_PURPOSE_get0(i); 225 if (!strcmp(xptmp->sname, sname)) 226 return i; 227 } 228 return -1; 229 } 230 LCRYPTO_ALIAS(X509_PURPOSE_get_by_sname); 231 232 int 233 X509_PURPOSE_get_by_id(int purpose) 234 { 235 /* 236 * Ensure the purpose identifier is between MIN and MAX inclusive. 237 * If so, translate it to an index into the xstandard[] table. 238 */ 239 if (purpose < X509_PURPOSE_MIN || purpose > X509_PURPOSE_MAX) 240 return -1; 241 242 return purpose - X509_PURPOSE_MIN; 243 } 244 245 int 246 X509_PURPOSE_get_id(const X509_PURPOSE *xp) 247 { 248 return xp->purpose; 249 } 250 LCRYPTO_ALIAS(X509_PURPOSE_get_id); 251 252 const char * 253 X509_PURPOSE_get0_name(const X509_PURPOSE *xp) 254 { 255 return xp->name; 256 } 257 LCRYPTO_ALIAS(X509_PURPOSE_get0_name); 258 259 const char * 260 X509_PURPOSE_get0_sname(const X509_PURPOSE *xp) 261 { 262 return xp->sname; 263 } 264 LCRYPTO_ALIAS(X509_PURPOSE_get0_sname); 265 266 int 267 X509_PURPOSE_get_trust(const X509_PURPOSE *xp) 268 { 269 return xp->trust; 270 } 271 272 /* 273 * List of NIDs of extensions supported by the verifier. If an extension 274 * is critical and doesn't appear in this list, then the certificate will 275 * normally be rejected. 276 */ 277 int 278 X509_supported_extension(X509_EXTENSION *ext) 279 { 280 switch (OBJ_obj2nid(X509_EXTENSION_get_object(ext))) { 281 case NID_basic_constraints: 282 case NID_certificate_policies: 283 case NID_ext_key_usage: 284 case NID_inhibit_any_policy: 285 case NID_key_usage: 286 case NID_name_constraints: 287 case NID_netscape_cert_type: 288 case NID_policy_constraints: 289 case NID_policy_mappings: 290 #ifndef OPENSSL_NO_RFC3779 291 case NID_sbgp_ipAddrBlock: 292 case NID_sbgp_autonomousSysNum: 293 #endif 294 case NID_subject_alt_name: 295 return 1; 296 default: 297 return 0; 298 } 299 } 300 LCRYPTO_ALIAS(X509_supported_extension); 301 302 static void 303 setup_dp(X509 *x, DIST_POINT *dp) 304 { 305 X509_NAME *iname = NULL; 306 int i; 307 308 if (dp->reasons) { 309 if (dp->reasons->length > 0) 310 dp->dp_reasons = dp->reasons->data[0]; 311 if (dp->reasons->length > 1) 312 dp->dp_reasons |= (dp->reasons->data[1] << 8); 313 dp->dp_reasons &= CRLDP_ALL_REASONS; 314 } else 315 dp->dp_reasons = CRLDP_ALL_REASONS; 316 if (!dp->distpoint || (dp->distpoint->type != 1)) 317 return; 318 for (i = 0; i < sk_GENERAL_NAME_num(dp->CRLissuer); i++) { 319 GENERAL_NAME *gen = sk_GENERAL_NAME_value(dp->CRLissuer, i); 320 if (gen->type == GEN_DIRNAME) { 321 iname = gen->d.directoryName; 322 break; 323 } 324 } 325 if (!iname) 326 iname = X509_get_issuer_name(x); 327 328 DIST_POINT_set_dpname(dp->distpoint, iname); 329 } 330 331 static void 332 setup_crldp(X509 *x) 333 { 334 int i; 335 336 x->crldp = X509_get_ext_d2i(x, NID_crl_distribution_points, &i, NULL); 337 if (x->crldp == NULL && i != -1) { 338 x->ex_flags |= EXFLAG_INVALID; 339 return; 340 } 341 342 for (i = 0; i < sk_DIST_POINT_num(x->crldp); i++) 343 setup_dp(x, sk_DIST_POINT_value(x->crldp, i)); 344 } 345 346 static int 347 x509_extension_oid_cmp(const X509_EXTENSION *const *a, 348 const X509_EXTENSION *const *b) 349 { 350 return OBJ_cmp((*a)->object, (*b)->object); 351 } 352 353 static int 354 x509_extension_oids_are_unique(X509 *x509) 355 { 356 STACK_OF(X509_EXTENSION) *exts = NULL; 357 const X509_EXTENSION *prev_ext, *curr_ext; 358 int i; 359 int ret = 0; 360 361 if (X509_get_ext_count(x509) <= 1) 362 goto done; 363 364 if ((exts = sk_X509_EXTENSION_dup(x509->cert_info->extensions)) == NULL) 365 goto err; 366 367 (void)sk_X509_EXTENSION_set_cmp_func(exts, x509_extension_oid_cmp); 368 sk_X509_EXTENSION_sort(exts); 369 370 prev_ext = sk_X509_EXTENSION_value(exts, 0); 371 for (i = 1; i < sk_X509_EXTENSION_num(exts); i++) { 372 curr_ext = sk_X509_EXTENSION_value(exts, i); 373 if (x509_extension_oid_cmp(&prev_ext, &curr_ext) == 0) 374 goto err; 375 prev_ext = curr_ext; 376 } 377 378 done: 379 ret = 1; 380 381 err: 382 sk_X509_EXTENSION_free(exts); 383 384 return ret; 385 } 386 387 static void 388 x509v3_cache_extensions_internal(X509 *x) 389 { 390 BASIC_CONSTRAINTS *bs; 391 ASN1_BIT_STRING *usage; 392 ASN1_BIT_STRING *ns; 393 EXTENDED_KEY_USAGE *extusage; 394 X509_EXTENSION *ex; 395 long version; 396 int i; 397 398 if (x->ex_flags & EXFLAG_SET) 399 return; 400 401 /* 402 * XXX - this should really only set EXFLAG_INVALID if extensions are 403 * invalid. However, the X509_digest() failure matches OpenSSL/BoringSSL 404 * behavior and the version checks are at least vaguely related to 405 * extensions. 406 */ 407 408 if (!X509_digest(x, X509_CERT_HASH_EVP, x->hash, NULL)) 409 x->ex_flags |= EXFLAG_INVALID; 410 411 version = X509_get_version(x); 412 if (version < 0 || version > 2) 413 x->ex_flags |= EXFLAG_INVALID; 414 if (version == 0) { 415 x->ex_flags |= EXFLAG_V1; 416 /* UIDs may only appear in v2 or v3 certs */ 417 if (x->cert_info->issuerUID != NULL || 418 x->cert_info->subjectUID != NULL) 419 x->ex_flags |= EXFLAG_INVALID; 420 } 421 if (version != 2 && X509_get_ext_count(x) != 0) 422 x->ex_flags |= EXFLAG_INVALID; 423 424 /* Handle basic constraints */ 425 if ((bs = X509_get_ext_d2i(x, NID_basic_constraints, &i, NULL))) { 426 if (bs->ca) 427 x->ex_flags |= EXFLAG_CA; 428 if (bs->pathlen) { 429 if ((bs->pathlen->type == V_ASN1_NEG_INTEGER) || 430 !bs->ca) { 431 x->ex_flags |= EXFLAG_INVALID; 432 x->ex_pathlen = 0; 433 } else 434 x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen); 435 } else 436 x->ex_pathlen = -1; 437 BASIC_CONSTRAINTS_free(bs); 438 x->ex_flags |= EXFLAG_BCONS; 439 } else if (i != -1) { 440 x->ex_flags |= EXFLAG_INVALID; 441 } 442 443 /* Handle key usage */ 444 if ((usage = X509_get_ext_d2i(x, NID_key_usage, &i, 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 } else if (i != -1) { 454 x->ex_flags |= EXFLAG_INVALID; 455 } 456 457 x->ex_xkusage = 0; 458 if ((extusage = X509_get_ext_d2i(x, NID_ext_key_usage, &i, NULL))) { 459 x->ex_flags |= EXFLAG_XKUSAGE; 460 for (i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) { 461 switch (OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage, i))) { 462 case NID_server_auth: 463 x->ex_xkusage |= XKU_SSL_SERVER; 464 break; 465 466 case NID_client_auth: 467 x->ex_xkusage |= XKU_SSL_CLIENT; 468 break; 469 470 case NID_email_protect: 471 x->ex_xkusage |= XKU_SMIME; 472 break; 473 474 case NID_code_sign: 475 x->ex_xkusage |= XKU_CODE_SIGN; 476 break; 477 478 case NID_ms_sgc: 479 case NID_ns_sgc: 480 x->ex_xkusage |= XKU_SGC; 481 break; 482 483 case NID_OCSP_sign: 484 x->ex_xkusage |= XKU_OCSP_SIGN; 485 break; 486 487 case NID_time_stamp: 488 x->ex_xkusage |= XKU_TIMESTAMP; 489 break; 490 491 case NID_dvcs: 492 x->ex_xkusage |= XKU_DVCS; 493 break; 494 495 case NID_anyExtendedKeyUsage: 496 x->ex_xkusage |= XKU_ANYEKU; 497 break; 498 } 499 } 500 sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free); 501 } else if (i != -1) { 502 x->ex_flags |= EXFLAG_INVALID; 503 } 504 505 if ((ns = X509_get_ext_d2i(x, NID_netscape_cert_type, &i, NULL))) { 506 if (ns->length > 0) 507 x->ex_nscert = ns->data[0]; 508 else 509 x->ex_nscert = 0; 510 x->ex_flags |= EXFLAG_NSCERT; 511 ASN1_BIT_STRING_free(ns); 512 } else if (i != -1) { 513 x->ex_flags |= EXFLAG_INVALID; 514 } 515 516 x->skid = X509_get_ext_d2i(x, NID_subject_key_identifier, &i, NULL); 517 if (x->skid == NULL && i != -1) 518 x->ex_flags |= EXFLAG_INVALID; 519 x->akid = X509_get_ext_d2i(x, NID_authority_key_identifier, &i, NULL); 520 if (x->akid == NULL && i != -1) 521 x->ex_flags |= EXFLAG_INVALID; 522 523 /* Does subject name match issuer? */ 524 if (!X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x))) { 525 x->ex_flags |= EXFLAG_SI; 526 /* If SKID matches AKID also indicate self signed. */ 527 if (X509_check_akid(x, x->akid) == X509_V_OK && 528 !ku_reject(x, KU_KEY_CERT_SIGN)) 529 x->ex_flags |= EXFLAG_SS; 530 } 531 532 x->altname = X509_get_ext_d2i(x, NID_subject_alt_name, &i, NULL); 533 if (x->altname == NULL && i != -1) 534 x->ex_flags |= EXFLAG_INVALID; 535 x->nc = X509_get_ext_d2i(x, NID_name_constraints, &i, NULL); 536 if (!x->nc && (i != -1)) 537 x->ex_flags |= EXFLAG_INVALID; 538 setup_crldp(x); 539 540 #ifndef OPENSSL_NO_RFC3779 541 x->rfc3779_addr = X509_get_ext_d2i(x, NID_sbgp_ipAddrBlock, &i, NULL); 542 if (x->rfc3779_addr == NULL && i != -1) 543 x->ex_flags |= EXFLAG_INVALID; 544 if (!X509v3_addr_is_canonical(x->rfc3779_addr)) 545 x->ex_flags |= EXFLAG_INVALID; 546 x->rfc3779_asid = X509_get_ext_d2i(x, NID_sbgp_autonomousSysNum, &i, NULL); 547 if (x->rfc3779_asid == NULL && i != -1) 548 x->ex_flags |= EXFLAG_INVALID; 549 if (!X509v3_asid_is_canonical(x->rfc3779_asid)) 550 x->ex_flags |= EXFLAG_INVALID; 551 #endif 552 553 for (i = 0; i < X509_get_ext_count(x); i++) { 554 ex = X509_get_ext(x, i); 555 if (OBJ_obj2nid(X509_EXTENSION_get_object(ex)) == 556 NID_freshest_crl) 557 x->ex_flags |= EXFLAG_FRESHEST; 558 if (!X509_EXTENSION_get_critical(ex)) 559 continue; 560 if (!X509_supported_extension(ex)) { 561 x->ex_flags |= EXFLAG_CRITICAL; 562 break; 563 } 564 } 565 566 if (!x509_extension_oids_are_unique(x)) 567 x->ex_flags |= EXFLAG_INVALID; 568 569 x->ex_flags |= EXFLAG_SET; 570 } 571 572 int 573 x509v3_cache_extensions(X509 *x) 574 { 575 if ((x->ex_flags & EXFLAG_SET) == 0) { 576 CRYPTO_w_lock(CRYPTO_LOCK_X509); 577 x509v3_cache_extensions_internal(x); 578 CRYPTO_w_unlock(CRYPTO_LOCK_X509); 579 } 580 581 return (x->ex_flags & EXFLAG_INVALID) == 0; 582 } 583 584 /* CA checks common to all purposes 585 * return codes: 586 * 0 not a CA 587 * 1 is a CA 588 * 2 basicConstraints absent so "maybe" a CA 589 * 3 basicConstraints absent but self signed V1. 590 * 4 basicConstraints absent but keyUsage present and keyCertSign asserted. 591 */ 592 593 static int 594 check_ca(const X509 *x) 595 { 596 /* keyUsage if present should allow cert signing */ 597 if (ku_reject(x, KU_KEY_CERT_SIGN)) 598 return 0; 599 if (x->ex_flags & EXFLAG_BCONS) { 600 if (x->ex_flags & EXFLAG_CA) 601 return 1; 602 /* If basicConstraints says not a CA then say so */ 603 else 604 return 0; 605 } else { 606 /* we support V1 roots for... uh, I don't really know why. */ 607 if ((x->ex_flags & V1_ROOT) == V1_ROOT) 608 return 3; 609 /* If key usage present it must have certSign so tolerate it */ 610 else if (x->ex_flags & EXFLAG_KUSAGE) 611 return 4; 612 /* Older certificates could have Netscape-specific CA types */ 613 else if (x->ex_flags & EXFLAG_NSCERT && 614 x->ex_nscert & NS_ANY_CA) 615 return 5; 616 /* can this still be regarded a CA certificate? I doubt it */ 617 return 0; 618 } 619 } 620 621 int 622 X509_check_ca(X509 *x) 623 { 624 x509v3_cache_extensions(x); 625 626 return check_ca(x); 627 } 628 LCRYPTO_ALIAS(X509_check_ca); 629 630 /* Check SSL CA: common checks for SSL client and server */ 631 static int 632 check_ssl_ca(const X509 *x) 633 { 634 int ca_ret; 635 636 ca_ret = check_ca(x); 637 if (!ca_ret) 638 return 0; 639 /* check nsCertType if present */ 640 if (ca_ret != 5 || x->ex_nscert & NS_SSL_CA) 641 return ca_ret; 642 else 643 return 0; 644 } 645 646 static int 647 check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, int ca) 648 { 649 if (xku_reject(x, XKU_SSL_CLIENT)) 650 return 0; 651 if (ca) 652 return check_ssl_ca(x); 653 /* We need to do digital signatures with it */ 654 if (ku_reject(x, KU_DIGITAL_SIGNATURE)) 655 return 0; 656 /* nsCertType if present should allow SSL client use */ 657 if (ns_reject(x, NS_SSL_CLIENT)) 658 return 0; 659 return 1; 660 } 661 662 static int 663 check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca) 664 { 665 if (xku_reject(x, XKU_SSL_SERVER|XKU_SGC)) 666 return 0; 667 if (ca) 668 return check_ssl_ca(x); 669 670 if (ns_reject(x, NS_SSL_SERVER)) 671 return 0; 672 /* Now as for keyUsage: we'll at least need to sign OR encipher */ 673 if (ku_reject(x, KU_DIGITAL_SIGNATURE|KU_KEY_ENCIPHERMENT)) 674 return 0; 675 676 return 1; 677 } 678 679 static int 680 check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca) 681 { 682 int ret; 683 684 ret = check_purpose_ssl_server(xp, x, ca); 685 if (!ret || ca) 686 return ret; 687 /* We need to encipher or Netscape complains */ 688 if (ku_reject(x, KU_KEY_ENCIPHERMENT)) 689 return 0; 690 return ret; 691 } 692 693 /* common S/MIME checks */ 694 static int 695 purpose_smime(const X509 *x, int ca) 696 { 697 if (xku_reject(x, XKU_SMIME)) 698 return 0; 699 if (ca) { 700 int ca_ret; 701 ca_ret = check_ca(x); 702 if (!ca_ret) 703 return 0; 704 /* check nsCertType if present */ 705 if (ca_ret != 5 || x->ex_nscert & NS_SMIME_CA) 706 return ca_ret; 707 else 708 return 0; 709 } 710 if (x->ex_flags & EXFLAG_NSCERT) { 711 if (x->ex_nscert & NS_SMIME) 712 return 1; 713 /* Workaround for some buggy certificates */ 714 if (x->ex_nscert & NS_SSL_CLIENT) 715 return 2; 716 return 0; 717 } 718 return 1; 719 } 720 721 static int 722 check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, int ca) 723 { 724 int ret; 725 726 ret = purpose_smime(x, ca); 727 if (!ret || ca) 728 return ret; 729 if (ku_reject(x, KU_DIGITAL_SIGNATURE|KU_NON_REPUDIATION)) 730 return 0; 731 return ret; 732 } 733 734 static int 735 check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, int ca) 736 { 737 int ret; 738 739 ret = purpose_smime(x, ca); 740 if (!ret || ca) 741 return ret; 742 if (ku_reject(x, KU_KEY_ENCIPHERMENT)) 743 return 0; 744 return ret; 745 } 746 747 static int 748 check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, int ca) 749 { 750 if (ca) { 751 int ca_ret; 752 if ((ca_ret = check_ca(x)) != 2) 753 return ca_ret; 754 else 755 return 0; 756 } 757 if (ku_reject(x, KU_CRL_SIGN)) 758 return 0; 759 return 1; 760 } 761 762 /* OCSP helper: this is *not* a full OCSP check. It just checks that 763 * each CA is valid. Additional checks must be made on the chain. 764 */ 765 static int 766 ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca) 767 { 768 /* Must be a valid CA. Should we really support the "I don't know" 769 value (2)? */ 770 if (ca) 771 return check_ca(x); 772 /* leaf certificate is checked in OCSP_verify() */ 773 return 1; 774 } 775 776 static int 777 check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x, int ca) 778 { 779 int i_ext; 780 781 /* If ca is true we must return if this is a valid CA certificate. */ 782 if (ca) 783 return check_ca(x); 784 785 /* 786 * Check the optional key usage field: 787 * if Key Usage is present, it must be one of digitalSignature 788 * and/or nonRepudiation (other values are not consistent and shall 789 * be rejected). 790 */ 791 if ((x->ex_flags & EXFLAG_KUSAGE) && 792 ((x->ex_kusage & ~(KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE)) || 793 !(x->ex_kusage & (KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE)))) 794 return 0; 795 796 /* Only time stamp key usage is permitted and it's required. */ 797 if (!(x->ex_flags & EXFLAG_XKUSAGE) || x->ex_xkusage != XKU_TIMESTAMP) 798 return 0; 799 800 /* Extended Key Usage MUST be critical */ 801 i_ext = X509_get_ext_by_NID((X509 *) x, NID_ext_key_usage, -1); 802 if (i_ext >= 0) { 803 X509_EXTENSION *ext = X509_get_ext((X509 *) x, i_ext); 804 if (!X509_EXTENSION_get_critical(ext)) 805 return 0; 806 } 807 808 return 1; 809 } 810 811 static int 812 no_check(const X509_PURPOSE *xp, const X509 *x, int ca) 813 { 814 return 1; 815 } 816 817 /* Various checks to see if one certificate issued the second. 818 * This can be used to prune a set of possible issuer certificates 819 * which have been looked up using some simple method such as by 820 * subject name. 821 * These are: 822 * 1. Check issuer_name(subject) == subject_name(issuer) 823 * 2. If akid(subject) exists check it matches issuer 824 * 3. If key_usage(issuer) exists check it supports certificate signing 825 * returns 0 for OK, positive for reason for mismatch, reasons match 826 * codes for X509_verify_cert() 827 */ 828 829 int 830 X509_check_issued(X509 *issuer, X509 *subject) 831 { 832 if (X509_NAME_cmp(X509_get_subject_name(issuer), 833 X509_get_issuer_name(subject))) 834 return X509_V_ERR_SUBJECT_ISSUER_MISMATCH; 835 836 if (!x509v3_cache_extensions(issuer)) 837 return X509_V_ERR_UNSPECIFIED; 838 if (!x509v3_cache_extensions(subject)) 839 return X509_V_ERR_UNSPECIFIED; 840 841 if (subject->akid) { 842 int ret = X509_check_akid(issuer, subject->akid); 843 if (ret != X509_V_OK) 844 return ret; 845 } 846 847 if (ku_reject(issuer, KU_KEY_CERT_SIGN)) 848 return X509_V_ERR_KEYUSAGE_NO_CERTSIGN; 849 return X509_V_OK; 850 } 851 LCRYPTO_ALIAS(X509_check_issued); 852 853 int 854 X509_check_akid(X509 *issuer, AUTHORITY_KEYID *akid) 855 { 856 if (!akid) 857 return X509_V_OK; 858 859 /* Check key ids (if present) */ 860 if (akid->keyid && issuer->skid && 861 ASN1_OCTET_STRING_cmp(akid->keyid, issuer->skid) ) 862 return X509_V_ERR_AKID_SKID_MISMATCH; 863 /* Check serial number */ 864 if (akid->serial && 865 ASN1_INTEGER_cmp(X509_get_serialNumber(issuer), akid->serial)) 866 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH; 867 /* Check issuer name */ 868 if (akid->issuer) { 869 /* Ugh, for some peculiar reason AKID includes 870 * SEQUENCE OF GeneralName. So look for a DirName. 871 * There may be more than one but we only take any 872 * notice of the first. 873 */ 874 GENERAL_NAMES *gens; 875 GENERAL_NAME *gen; 876 X509_NAME *nm = NULL; 877 int i; 878 gens = akid->issuer; 879 for (i = 0; i < sk_GENERAL_NAME_num(gens); i++) { 880 gen = sk_GENERAL_NAME_value(gens, i); 881 if (gen->type == GEN_DIRNAME) { 882 nm = gen->d.dirn; 883 break; 884 } 885 } 886 if (nm && X509_NAME_cmp(nm, X509_get_issuer_name(issuer))) 887 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH; 888 } 889 return X509_V_OK; 890 } 891 LCRYPTO_ALIAS(X509_check_akid); 892 893 uint32_t 894 X509_get_extension_flags(X509 *x) 895 { 896 /* Call for side-effect of computing hash and caching extensions */ 897 if (X509_check_purpose(x, -1, -1) != 1) 898 return EXFLAG_INVALID; 899 900 return x->ex_flags; 901 } 902 LCRYPTO_ALIAS(X509_get_extension_flags); 903 904 uint32_t 905 X509_get_key_usage(X509 *x) 906 { 907 /* Call for side-effect of computing hash and caching extensions */ 908 if (X509_check_purpose(x, -1, -1) != 1) 909 return 0; 910 911 if (x->ex_flags & EXFLAG_KUSAGE) 912 return x->ex_kusage; 913 914 return UINT32_MAX; 915 } 916 LCRYPTO_ALIAS(X509_get_key_usage); 917 918 uint32_t 919 X509_get_extended_key_usage(X509 *x) 920 { 921 /* Call for side-effect of computing hash and caching extensions */ 922 if (X509_check_purpose(x, -1, -1) != 1) 923 return 0; 924 925 if (x->ex_flags & EXFLAG_XKUSAGE) 926 return x->ex_xkusage; 927 928 return UINT32_MAX; 929 } 930 LCRYPTO_ALIAS(X509_get_extended_key_usage); 931