1 /* v3_purp.c */ 2 /* 3 * Written by Dr Stephen N Henson (steve (at) 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 (at) 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 (at) cryptsoft.com). This product includes software written by Tim 56 * Hudson (tjh (at) cryptsoft.com). */ 57 58 #include <stdio.h> 59 60 #include <string.h> 61 62 #include <openssl/buf.h> 63 #include <openssl/err.h> 64 #include <openssl/digest.h> 65 #include <openssl/mem.h> 66 #include <openssl/obj.h> 67 #include <openssl/thread.h> 68 #include <openssl/x509_vfy.h> 69 #include <openssl/x509v3.h> 70 71 #include "../internal.h" 72 73 #define V1_ROOT (EXFLAG_V1|EXFLAG_SS) 74 #define ku_reject(x, usage) \ 75 (((x)->ex_flags & EXFLAG_KUSAGE) && !((x)->ex_kusage & (usage))) 76 #define xku_reject(x, usage) \ 77 (((x)->ex_flags & EXFLAG_XKUSAGE) && !((x)->ex_xkusage & (usage))) 78 #define ns_reject(x, usage) \ 79 (((x)->ex_flags & EXFLAG_NSCERT) && !((x)->ex_nscert & (usage))) 80 81 static void x509v3_cache_extensions(X509 *x); 82 83 static int check_ssl_ca(const X509 *x); 84 static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, 85 int ca); 86 static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, 87 int ca); 88 static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, 89 int ca); 90 static int purpose_smime(const X509 *x, int ca); 91 static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, 92 int ca); 93 static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, 94 int ca); 95 static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, 96 int ca); 97 static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x, 98 int ca); 99 static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca); 100 static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca); 101 102 static int xp_cmp(const X509_PURPOSE **a, const X509_PURPOSE **b); 103 static void xptable_free(X509_PURPOSE *p); 104 105 static X509_PURPOSE xstandard[] = { 106 {X509_PURPOSE_SSL_CLIENT, X509_TRUST_SSL_CLIENT, 0, 107 check_purpose_ssl_client, (char *)"SSL client", (char *)"sslclient", 108 NULL}, 109 {X509_PURPOSE_SSL_SERVER, X509_TRUST_SSL_SERVER, 0, 110 check_purpose_ssl_server, (char *)"SSL server", (char *)"sslserver", 111 NULL}, 112 {X509_PURPOSE_NS_SSL_SERVER, X509_TRUST_SSL_SERVER, 0, 113 check_purpose_ns_ssl_server, (char *)"Netscape SSL server", 114 (char *)"nssslserver", NULL}, 115 {X509_PURPOSE_SMIME_SIGN, X509_TRUST_EMAIL, 0, check_purpose_smime_sign, 116 (char *)"S/MIME signing", (char *)"smimesign", NULL}, 117 {X509_PURPOSE_SMIME_ENCRYPT, X509_TRUST_EMAIL, 0, 118 check_purpose_smime_encrypt, (char *)"S/MIME encryption", 119 (char *)"smimeencrypt", NULL}, 120 {X509_PURPOSE_CRL_SIGN, X509_TRUST_COMPAT, 0, check_purpose_crl_sign, 121 (char *)"CRL signing", (char *)"crlsign", NULL}, 122 {X509_PURPOSE_ANY, X509_TRUST_DEFAULT, 0, no_check, (char *)"Any Purpose", 123 (char *)"any", NULL}, 124 {X509_PURPOSE_OCSP_HELPER, X509_TRUST_COMPAT, 0, ocsp_helper, 125 (char *)"OCSP helper", (char *)"ocsphelper", NULL}, 126 {X509_PURPOSE_TIMESTAMP_SIGN, X509_TRUST_TSA, 0, 127 check_purpose_timestamp_sign, (char *)"Time Stamp signing", 128 (char *)"timestampsign", NULL}, 129 }; 130 131 #define X509_PURPOSE_COUNT (sizeof(xstandard)/sizeof(X509_PURPOSE)) 132 133 static STACK_OF(X509_PURPOSE) *xptable = NULL; 134 135 static int xp_cmp(const X509_PURPOSE **a, const X509_PURPOSE **b) 136 { 137 return (*a)->purpose - (*b)->purpose; 138 } 139 140 /* 141 * As much as I'd like to make X509_check_purpose use a "const" X509* I 142 * really can't because it does recalculate hashes and do other non-const 143 * things. 144 */ 145 int X509_check_purpose(X509 *x, int id, int ca) 146 { 147 int idx; 148 const X509_PURPOSE *pt; 149 x509v3_cache_extensions(x); 150 if (id == -1) 151 return 1; 152 idx = X509_PURPOSE_get_by_id(id); 153 if (idx == -1) 154 return -1; 155 pt = X509_PURPOSE_get0(idx); 156 return pt->check_purpose(pt, x, ca); 157 } 158 159 int X509_PURPOSE_set(int *p, int purpose) 160 { 161 if (X509_PURPOSE_get_by_id(purpose) == -1) { 162 OPENSSL_PUT_ERROR(X509V3, X509V3_R_INVALID_PURPOSE); 163 return 0; 164 } 165 *p = purpose; 166 return 1; 167 } 168 169 int X509_PURPOSE_get_count(void) 170 { 171 if (!xptable) 172 return X509_PURPOSE_COUNT; 173 return sk_X509_PURPOSE_num(xptable) + X509_PURPOSE_COUNT; 174 } 175 176 X509_PURPOSE *X509_PURPOSE_get0(int idx) 177 { 178 if (idx < 0) 179 return NULL; 180 if (idx < (int)X509_PURPOSE_COUNT) 181 return xstandard + idx; 182 return sk_X509_PURPOSE_value(xptable, idx - X509_PURPOSE_COUNT); 183 } 184 185 int X509_PURPOSE_get_by_sname(char *sname) 186 { 187 int i; 188 X509_PURPOSE *xptmp; 189 for (i = 0; i < X509_PURPOSE_get_count(); i++) { 190 xptmp = X509_PURPOSE_get0(i); 191 if (!strcmp(xptmp->sname, sname)) 192 return i; 193 } 194 return -1; 195 } 196 197 int X509_PURPOSE_get_by_id(int purpose) 198 { 199 X509_PURPOSE tmp; 200 size_t idx; 201 202 if ((purpose >= X509_PURPOSE_MIN) && (purpose <= X509_PURPOSE_MAX)) 203 return purpose - X509_PURPOSE_MIN; 204 tmp.purpose = purpose; 205 if (!xptable) 206 return -1; 207 208 if (!sk_X509_PURPOSE_find(xptable, &idx, &tmp)) 209 return -1; 210 return idx + X509_PURPOSE_COUNT; 211 } 212 213 int X509_PURPOSE_add(int id, int trust, int flags, 214 int (*ck) (const X509_PURPOSE *, const X509 *, int), 215 char *name, char *sname, void *arg) 216 { 217 int idx; 218 X509_PURPOSE *ptmp; 219 char *name_dup, *sname_dup; 220 221 /* 222 * This is set according to what we change: application can't set it 223 */ 224 flags &= ~X509_PURPOSE_DYNAMIC; 225 /* This will always be set for application modified trust entries */ 226 flags |= X509_PURPOSE_DYNAMIC_NAME; 227 /* Get existing entry if any */ 228 idx = X509_PURPOSE_get_by_id(id); 229 /* Need a new entry */ 230 if (idx == -1) { 231 if (!(ptmp = OPENSSL_malloc(sizeof(X509_PURPOSE)))) { 232 OPENSSL_PUT_ERROR(X509V3, ERR_R_MALLOC_FAILURE); 233 return 0; 234 } 235 ptmp->flags = X509_PURPOSE_DYNAMIC; 236 } else 237 ptmp = X509_PURPOSE_get0(idx); 238 239 /* Duplicate the supplied names. */ 240 name_dup = BUF_strdup(name); 241 sname_dup = BUF_strdup(sname); 242 if (name_dup == NULL || sname_dup == NULL) { 243 OPENSSL_PUT_ERROR(X509V3, ERR_R_MALLOC_FAILURE); 244 if (name_dup != NULL) 245 OPENSSL_free(name_dup); 246 if (sname_dup != NULL) 247 OPENSSL_free(sname_dup); 248 if (idx == -1) 249 OPENSSL_free(ptmp); 250 return 0; 251 } 252 253 /* OPENSSL_free existing name if dynamic */ 254 if (ptmp->flags & X509_PURPOSE_DYNAMIC_NAME) { 255 OPENSSL_free(ptmp->name); 256 OPENSSL_free(ptmp->sname); 257 } 258 /* dup supplied name */ 259 ptmp->name = name_dup; 260 ptmp->sname = sname_dup; 261 /* Keep the dynamic flag of existing entry */ 262 ptmp->flags &= X509_PURPOSE_DYNAMIC; 263 /* Set all other flags */ 264 ptmp->flags |= flags; 265 266 ptmp->purpose = id; 267 ptmp->trust = trust; 268 ptmp->check_purpose = ck; 269 ptmp->usr_data = arg; 270 271 /* If its a new entry manage the dynamic table */ 272 if (idx == -1) { 273 if (!xptable && !(xptable = sk_X509_PURPOSE_new(xp_cmp))) { 274 OPENSSL_PUT_ERROR(X509V3, ERR_R_MALLOC_FAILURE); 275 xptable_free(ptmp); 276 return 0; 277 } 278 if (!sk_X509_PURPOSE_push(xptable, ptmp)) { 279 OPENSSL_PUT_ERROR(X509V3, ERR_R_MALLOC_FAILURE); 280 xptable_free(ptmp); 281 return 0; 282 } 283 } 284 return 1; 285 } 286 287 static void xptable_free(X509_PURPOSE *p) 288 { 289 if (!p) 290 return; 291 if (p->flags & X509_PURPOSE_DYNAMIC) { 292 if (p->flags & X509_PURPOSE_DYNAMIC_NAME) { 293 OPENSSL_free(p->name); 294 OPENSSL_free(p->sname); 295 } 296 OPENSSL_free(p); 297 } 298 } 299 300 void X509_PURPOSE_cleanup(void) 301 { 302 unsigned int i; 303 sk_X509_PURPOSE_pop_free(xptable, xptable_free); 304 for (i = 0; i < X509_PURPOSE_COUNT; i++) 305 xptable_free(xstandard + i); 306 xptable = NULL; 307 } 308 309 int X509_PURPOSE_get_id(X509_PURPOSE *xp) 310 { 311 return xp->purpose; 312 } 313 314 char *X509_PURPOSE_get0_name(X509_PURPOSE *xp) 315 { 316 return xp->name; 317 } 318 319 char *X509_PURPOSE_get0_sname(X509_PURPOSE *xp) 320 { 321 return xp->sname; 322 } 323 324 int X509_PURPOSE_get_trust(X509_PURPOSE *xp) 325 { 326 return xp->trust; 327 } 328 329 static int nid_cmp(const void *void_a, const void *void_b) 330 { 331 const int *a = void_a, *b = void_b; 332 333 return *a - *b; 334 } 335 336 int X509_supported_extension(X509_EXTENSION *ex) 337 { 338 /* 339 * This table is a list of the NIDs of supported extensions: that is 340 * those which are used by the verify process. If an extension is 341 * critical and doesn't appear in this list then the verify process will 342 * normally reject the certificate. The list must be kept in numerical 343 * order because it will be searched using bsearch. 344 */ 345 346 static const int supported_nids[] = { 347 NID_netscape_cert_type, /* 71 */ 348 NID_key_usage, /* 83 */ 349 NID_subject_alt_name, /* 85 */ 350 NID_basic_constraints, /* 87 */ 351 NID_certificate_policies, /* 89 */ 352 NID_ext_key_usage, /* 126 */ 353 NID_policy_constraints, /* 401 */ 354 NID_proxyCertInfo, /* 663 */ 355 NID_name_constraints, /* 666 */ 356 NID_policy_mappings, /* 747 */ 357 NID_inhibit_any_policy /* 748 */ 358 }; 359 360 int ex_nid = OBJ_obj2nid(X509_EXTENSION_get_object(ex)); 361 362 if (ex_nid == NID_undef) 363 return 0; 364 365 if (bsearch 366 (&ex_nid, supported_nids, sizeof(supported_nids) / sizeof(int), 367 sizeof(int), nid_cmp) != NULL) 368 return 1; 369 return 0; 370 } 371 372 static void setup_dp(X509 *x, DIST_POINT *dp) 373 { 374 X509_NAME *iname = NULL; 375 size_t i; 376 if (dp->reasons) { 377 if (dp->reasons->length > 0) 378 dp->dp_reasons = dp->reasons->data[0]; 379 if (dp->reasons->length > 1) 380 dp->dp_reasons |= (dp->reasons->data[1] << 8); 381 dp->dp_reasons &= CRLDP_ALL_REASONS; 382 } else 383 dp->dp_reasons = CRLDP_ALL_REASONS; 384 if (!dp->distpoint || (dp->distpoint->type != 1)) 385 return; 386 for (i = 0; i < sk_GENERAL_NAME_num(dp->CRLissuer); i++) { 387 GENERAL_NAME *gen = sk_GENERAL_NAME_value(dp->CRLissuer, i); 388 if (gen->type == GEN_DIRNAME) { 389 iname = gen->d.directoryName; 390 break; 391 } 392 } 393 if (!iname) 394 iname = X509_get_issuer_name(x); 395 396 DIST_POINT_set_dpname(dp->distpoint, iname); 397 398 } 399 400 static void setup_crldp(X509 *x) 401 { 402 size_t i; 403 x->crldp = X509_get_ext_d2i(x, NID_crl_distribution_points, NULL, NULL); 404 for (i = 0; i < sk_DIST_POINT_num(x->crldp); i++) 405 setup_dp(x, sk_DIST_POINT_value(x->crldp, i)); 406 } 407 408 static void x509v3_cache_extensions(X509 *x) 409 { 410 BASIC_CONSTRAINTS *bs; 411 PROXY_CERT_INFO_EXTENSION *pci; 412 ASN1_BIT_STRING *usage; 413 ASN1_BIT_STRING *ns; 414 EXTENDED_KEY_USAGE *extusage; 415 X509_EXTENSION *ex; 416 size_t i; 417 int j; 418 419 CRYPTO_MUTEX_lock_read(&x->lock); 420 const int is_set = x->ex_flags & EXFLAG_SET; 421 CRYPTO_MUTEX_unlock_read(&x->lock); 422 423 if (is_set) { 424 return; 425 } 426 427 CRYPTO_MUTEX_lock_write(&x->lock); 428 if (x->ex_flags & EXFLAG_SET) { 429 CRYPTO_MUTEX_unlock_write(&x->lock); 430 return; 431 } 432 433 X509_digest(x, EVP_sha1(), x->sha1_hash, NULL); 434 /* V1 should mean no extensions ... */ 435 if (!X509_get_version(x)) 436 x->ex_flags |= EXFLAG_V1; 437 /* Handle basic constraints */ 438 if ((bs = X509_get_ext_d2i(x, NID_basic_constraints, NULL, NULL))) { 439 if (bs->ca) 440 x->ex_flags |= EXFLAG_CA; 441 if (bs->pathlen) { 442 if ((bs->pathlen->type == V_ASN1_NEG_INTEGER) 443 || !bs->ca) { 444 x->ex_flags |= EXFLAG_INVALID; 445 x->ex_pathlen = 0; 446 } else 447 x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen); 448 } else 449 x->ex_pathlen = -1; 450 BASIC_CONSTRAINTS_free(bs); 451 x->ex_flags |= EXFLAG_BCONS; 452 } 453 /* Handle proxy certificates */ 454 if ((pci = X509_get_ext_d2i(x, NID_proxyCertInfo, NULL, NULL))) { 455 if (x->ex_flags & EXFLAG_CA 456 || X509_get_ext_by_NID(x, NID_subject_alt_name, -1) >= 0 457 || X509_get_ext_by_NID(x, NID_issuer_alt_name, -1) >= 0) { 458 x->ex_flags |= EXFLAG_INVALID; 459 } 460 if (pci->pcPathLengthConstraint) { 461 x->ex_pcpathlen = ASN1_INTEGER_get(pci->pcPathLengthConstraint); 462 } else 463 x->ex_pcpathlen = -1; 464 PROXY_CERT_INFO_EXTENSION_free(pci); 465 x->ex_flags |= EXFLAG_PROXY; 466 } 467 /* Handle key usage */ 468 if ((usage = X509_get_ext_d2i(x, NID_key_usage, NULL, NULL))) { 469 if (usage->length > 0) { 470 x->ex_kusage = usage->data[0]; 471 if (usage->length > 1) 472 x->ex_kusage |= usage->data[1] << 8; 473 } else 474 x->ex_kusage = 0; 475 x->ex_flags |= EXFLAG_KUSAGE; 476 ASN1_BIT_STRING_free(usage); 477 } 478 x->ex_xkusage = 0; 479 if ((extusage = X509_get_ext_d2i(x, NID_ext_key_usage, NULL, NULL))) { 480 x->ex_flags |= EXFLAG_XKUSAGE; 481 for (i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) { 482 switch (OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage, i))) { 483 case NID_server_auth: 484 x->ex_xkusage |= XKU_SSL_SERVER; 485 break; 486 487 case NID_client_auth: 488 x->ex_xkusage |= XKU_SSL_CLIENT; 489 break; 490 491 case NID_email_protect: 492 x->ex_xkusage |= XKU_SMIME; 493 break; 494 495 case NID_code_sign: 496 x->ex_xkusage |= XKU_CODE_SIGN; 497 break; 498 499 case NID_ms_sgc: 500 case NID_ns_sgc: 501 x->ex_xkusage |= XKU_SGC; 502 break; 503 504 case NID_OCSP_sign: 505 x->ex_xkusage |= XKU_OCSP_SIGN; 506 break; 507 508 case NID_time_stamp: 509 x->ex_xkusage |= XKU_TIMESTAMP; 510 break; 511 512 case NID_dvcs: 513 x->ex_xkusage |= XKU_DVCS; 514 break; 515 516 case NID_anyExtendedKeyUsage: 517 x->ex_xkusage |= XKU_ANYEKU; 518 break; 519 } 520 } 521 sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free); 522 } 523 524 if ((ns = X509_get_ext_d2i(x, NID_netscape_cert_type, NULL, NULL))) { 525 if (ns->length > 0) 526 x->ex_nscert = ns->data[0]; 527 else 528 x->ex_nscert = 0; 529 x->ex_flags |= EXFLAG_NSCERT; 530 ASN1_BIT_STRING_free(ns); 531 } 532 x->skid = X509_get_ext_d2i(x, NID_subject_key_identifier, NULL, NULL); 533 x->akid = X509_get_ext_d2i(x, NID_authority_key_identifier, NULL, NULL); 534 /* Does subject name match issuer ? */ 535 if (!X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x))) { 536 x->ex_flags |= EXFLAG_SI; 537 /* If SKID matches AKID also indicate self signed */ 538 if (X509_check_akid(x, x->akid) == X509_V_OK && 539 !ku_reject(x, KU_KEY_CERT_SIGN)) 540 x->ex_flags |= EXFLAG_SS; 541 } 542 x->altname = X509_get_ext_d2i(x, NID_subject_alt_name, NULL, NULL); 543 x->nc = X509_get_ext_d2i(x, NID_name_constraints, &j, NULL); 544 if (!x->nc && (j != -1)) 545 x->ex_flags |= EXFLAG_INVALID; 546 setup_crldp(x); 547 548 for (j = 0; j < X509_get_ext_count(x); j++) { 549 ex = X509_get_ext(x, j); 550 if (OBJ_obj2nid(X509_EXTENSION_get_object(ex)) 551 == NID_freshest_crl) 552 x->ex_flags |= EXFLAG_FRESHEST; 553 if (!X509_EXTENSION_get_critical(ex)) 554 continue; 555 if (!X509_supported_extension(ex)) { 556 x->ex_flags |= EXFLAG_CRITICAL; 557 break; 558 } 559 } 560 x->ex_flags |= EXFLAG_SET; 561 562 CRYPTO_MUTEX_unlock_write(&x->lock); 563 } 564 565 /* 566 * CA checks common to all purposes return codes: 0 not a CA 1 is a CA 2 567 * basicConstraints absent so "maybe" a CA 3 basicConstraints absent but self 568 * signed V1. 4 basicConstraints absent but keyUsage present and keyCertSign 569 * asserted. 570 */ 571 572 static int check_ca(const X509 *x) 573 { 574 /* keyUsage if present should allow cert signing */ 575 if (ku_reject(x, KU_KEY_CERT_SIGN)) 576 return 0; 577 if (x->ex_flags & EXFLAG_BCONS) { 578 if (x->ex_flags & EXFLAG_CA) 579 return 1; 580 /* If basicConstraints says not a CA then say so */ 581 else 582 return 0; 583 } else { 584 /* we support V1 roots for... uh, I don't really know why. */ 585 if ((x->ex_flags & V1_ROOT) == V1_ROOT) 586 return 3; 587 /* 588 * If key usage present it must have certSign so tolerate it 589 */ 590 else if (x->ex_flags & EXFLAG_KUSAGE) 591 return 4; 592 /* Older certificates could have Netscape-specific CA types */ 593 else if (x->ex_flags & EXFLAG_NSCERT && x->ex_nscert & NS_ANY_CA) 594 return 5; 595 /* can this still be regarded a CA certificate? I doubt it */ 596 return 0; 597 } 598 } 599 600 int X509_check_ca(X509 *x) 601 { 602 x509v3_cache_extensions(x); 603 return check_ca(x); 604 } 605 606 /* Check SSL CA: common checks for SSL client and server */ 607 static int check_ssl_ca(const X509 *x) 608 { 609 int ca_ret; 610 ca_ret = check_ca(x); 611 if (!ca_ret) 612 return 0; 613 /* check nsCertType if present */ 614 if (ca_ret != 5 || x->ex_nscert & NS_SSL_CA) 615 return ca_ret; 616 else 617 return 0; 618 } 619 620 static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, 621 int ca) 622 { 623 if (xku_reject(x, XKU_SSL_CLIENT)) 624 return 0; 625 if (ca) 626 return check_ssl_ca(x); 627 /* We need to do digital signatures or key agreement */ 628 if (ku_reject(x, KU_DIGITAL_SIGNATURE | KU_KEY_AGREEMENT)) 629 return 0; 630 /* nsCertType if present should allow SSL client use */ 631 if (ns_reject(x, NS_SSL_CLIENT)) 632 return 0; 633 return 1; 634 } 635 636 /* 637 * Key usage needed for TLS/SSL server: digital signature, encipherment or 638 * key agreement. The ssl code can check this more thoroughly for individual 639 * key types. 640 */ 641 #define KU_TLS \ 642 (KU_DIGITAL_SIGNATURE|KU_KEY_ENCIPHERMENT|KU_KEY_AGREEMENT) 643 644 static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, 645 int ca) 646 { 647 if (xku_reject(x, XKU_SSL_SERVER | XKU_SGC)) 648 return 0; 649 if (ca) 650 return check_ssl_ca(x); 651 652 if (ns_reject(x, NS_SSL_SERVER)) 653 return 0; 654 if (ku_reject(x, KU_TLS)) 655 return 0; 656 657 return 1; 658 659 } 660 661 static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, 662 int ca) 663 { 664 int ret; 665 ret = check_purpose_ssl_server(xp, x, ca); 666 if (!ret || ca) 667 return ret; 668 /* We need to encipher or Netscape complains */ 669 if (ku_reject(x, KU_KEY_ENCIPHERMENT)) 670 return 0; 671 return ret; 672 } 673 674 /* common S/MIME checks */ 675 static int purpose_smime(const X509 *x, int ca) 676 { 677 if (xku_reject(x, XKU_SMIME)) 678 return 0; 679 if (ca) { 680 int ca_ret; 681 ca_ret = check_ca(x); 682 if (!ca_ret) 683 return 0; 684 /* check nsCertType if present */ 685 if (ca_ret != 5 || x->ex_nscert & NS_SMIME_CA) 686 return ca_ret; 687 else 688 return 0; 689 } 690 if (x->ex_flags & EXFLAG_NSCERT) { 691 if (x->ex_nscert & NS_SMIME) 692 return 1; 693 /* Workaround for some buggy certificates */ 694 if (x->ex_nscert & NS_SSL_CLIENT) 695 return 2; 696 return 0; 697 } 698 return 1; 699 } 700 701 static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, 702 int ca) 703 { 704 int ret; 705 ret = purpose_smime(x, ca); 706 if (!ret || ca) 707 return ret; 708 if (ku_reject(x, KU_DIGITAL_SIGNATURE | KU_NON_REPUDIATION)) 709 return 0; 710 return ret; 711 } 712 713 static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, 714 int ca) 715 { 716 int ret; 717 ret = purpose_smime(x, ca); 718 if (!ret || ca) 719 return ret; 720 if (ku_reject(x, KU_KEY_ENCIPHERMENT)) 721 return 0; 722 return ret; 723 } 724 725 static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, 726 int ca) 727 { 728 if (ca) { 729 int ca_ret; 730 if ((ca_ret = check_ca(x)) != 2) 731 return ca_ret; 732 else 733 return 0; 734 } 735 if (ku_reject(x, KU_CRL_SIGN)) 736 return 0; 737 return 1; 738 } 739 740 /* 741 * OCSP helper: this is *not* a full OCSP check. It just checks that each CA 742 * is valid. Additional checks must be made on the chain. 743 */ 744 745 static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca) 746 { 747 /* 748 * Must be a valid CA. Should we really support the "I don't know" value 749 * (2)? 750 */ 751 if (ca) 752 return check_ca(x); 753 /* leaf certificate is checked in OCSP_verify() */ 754 return 1; 755 } 756 757 static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x, 758 int ca) 759 { 760 int i_ext; 761 762 /* If ca is true we must return if this is a valid CA certificate. */ 763 if (ca) 764 return check_ca(x); 765 766 /* 767 * Check the optional key usage field: 768 * if Key Usage is present, it must be one of digitalSignature 769 * and/or nonRepudiation (other values are not consistent and shall 770 * be rejected). 771 */ 772 if ((x->ex_flags & EXFLAG_KUSAGE) 773 && ((x->ex_kusage & ~(KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE)) || 774 !(x->ex_kusage & (KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE)))) 775 return 0; 776 777 /* Only time stamp key usage is permitted and it's required. */ 778 if (!(x->ex_flags & EXFLAG_XKUSAGE) || x->ex_xkusage != XKU_TIMESTAMP) 779 return 0; 780 781 /* Extended Key Usage MUST be critical */ 782 i_ext = X509_get_ext_by_NID((X509 *)x, NID_ext_key_usage, -1); 783 if (i_ext >= 0) { 784 X509_EXTENSION *ext = X509_get_ext((X509 *)x, i_ext); 785 if (!X509_EXTENSION_get_critical(ext)) 786 return 0; 787 } 788 789 return 1; 790 } 791 792 static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca) 793 { 794 return 1; 795 } 796 797 /* 798 * Various checks to see if one certificate issued the second. This can be 799 * used to prune a set of possible issuer certificates which have been looked 800 * up using some simple method such as by subject name. These are: 1. Check 801 * issuer_name(subject) == subject_name(issuer) 2. If akid(subject) exists 802 * check it matches issuer 3. If key_usage(issuer) exists check it supports 803 * certificate signing returns 0 for OK, positive for reason for mismatch, 804 * reasons match codes for X509_verify_cert() 805 */ 806 807 int X509_check_issued(X509 *issuer, X509 *subject) 808 { 809 if (X509_NAME_cmp(X509_get_subject_name(issuer), 810 X509_get_issuer_name(subject))) 811 return X509_V_ERR_SUBJECT_ISSUER_MISMATCH; 812 x509v3_cache_extensions(issuer); 813 x509v3_cache_extensions(subject); 814 815 if (subject->akid) { 816 int ret = X509_check_akid(issuer, subject->akid); 817 if (ret != X509_V_OK) 818 return ret; 819 } 820 821 if (subject->ex_flags & EXFLAG_PROXY) { 822 if (ku_reject(issuer, KU_DIGITAL_SIGNATURE)) 823 return X509_V_ERR_KEYUSAGE_NO_DIGITAL_SIGNATURE; 824 } else if (ku_reject(issuer, KU_KEY_CERT_SIGN)) 825 return X509_V_ERR_KEYUSAGE_NO_CERTSIGN; 826 return X509_V_OK; 827 } 828 829 int X509_check_akid(X509 *issuer, AUTHORITY_KEYID *akid) 830 { 831 832 if (!akid) 833 return X509_V_OK; 834 835 /* Check key ids (if present) */ 836 if (akid->keyid && issuer->skid && 837 ASN1_OCTET_STRING_cmp(akid->keyid, issuer->skid)) 838 return X509_V_ERR_AKID_SKID_MISMATCH; 839 /* Check serial number */ 840 if (akid->serial && 841 ASN1_INTEGER_cmp(X509_get_serialNumber(issuer), akid->serial)) 842 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH; 843 /* Check issuer name */ 844 if (akid->issuer) { 845 /* 846 * Ugh, for some peculiar reason AKID includes SEQUENCE OF 847 * GeneralName. So look for a DirName. There may be more than one but 848 * we only take any notice of the first. 849 */ 850 GENERAL_NAMES *gens; 851 GENERAL_NAME *gen; 852 X509_NAME *nm = NULL; 853 size_t i; 854 gens = akid->issuer; 855 for (i = 0; i < sk_GENERAL_NAME_num(gens); i++) { 856 gen = sk_GENERAL_NAME_value(gens, i); 857 if (gen->type == GEN_DIRNAME) { 858 nm = gen->d.dirn; 859 break; 860 } 861 } 862 if (nm && X509_NAME_cmp(nm, X509_get_issuer_name(issuer))) 863 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH; 864 } 865 return X509_V_OK; 866 } 867
