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) 1999-2018 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; 131 132 x509v3_cache_extensions(x); 133 134 /* Return if side-effect only call */ 135 if (id == -1) 136 return 1; 137 idx = X509_PURPOSE_get_by_id(id); 138 if (idx == -1) 139 return -1; 140 pt = X509_PURPOSE_get0(idx); 141 return pt->check_purpose(pt, x, ca); 142} 143 144int X509_PURPOSE_set(int *p, int purpose) 145{ 146 if (X509_PURPOSE_get_by_id(purpose) == -1) { 147 X509V3err(X509V3_F_X509_PURPOSE_SET, X509V3_R_INVALID_PURPOSE); 148 return 0; 149 } 150 *p = purpose; 151 return 1; 152} 153 154int X509_PURPOSE_get_count(void) 155{ 156 if (!xptable) 157 return X509_PURPOSE_COUNT; 158 return sk_X509_PURPOSE_num(xptable) + X509_PURPOSE_COUNT; 159} 160 161X509_PURPOSE *X509_PURPOSE_get0(int idx) 162{ 163 if (idx < 0) 164 return NULL; 165 if (idx < (int)X509_PURPOSE_COUNT) 166 return xstandard + idx; 167 return sk_X509_PURPOSE_value(xptable, idx - X509_PURPOSE_COUNT); 168} 169 170int X509_PURPOSE_get_by_sname(char *sname) 171{ 172 int i; 173 X509_PURPOSE *xptmp; 174 for (i = 0; i < X509_PURPOSE_get_count(); i++) { 175 xptmp = X509_PURPOSE_get0(i); 176 if (!strcmp(xptmp->sname, sname)) 177 return i; 178 } 179 return -1; 180} 181 182int X509_PURPOSE_get_by_id(int purpose) 183{ 184 X509_PURPOSE tmp; 185 int idx; 186 if ((purpose >= X509_PURPOSE_MIN) && (purpose <= X509_PURPOSE_MAX)) 187 return purpose - X509_PURPOSE_MIN; 188 tmp.purpose = purpose; 189 if (!xptable) 190 return -1; 191 idx = sk_X509_PURPOSE_find(xptable, &tmp); 192 if (idx == -1) 193 return -1; 194 return idx + X509_PURPOSE_COUNT; 195} 196 197int X509_PURPOSE_add(int id, int trust, int flags, 198 int (*ck) (const X509_PURPOSE *, const X509 *, int), 199 char *name, char *sname, void *arg) 200{ 201 int idx; 202 X509_PURPOSE *ptmp; 203 /* 204 * This is set according to what we change: application can't set it 205 */ 206 flags &= ~X509_PURPOSE_DYNAMIC; 207 /* This will always be set for application modified trust entries */ 208 flags |= X509_PURPOSE_DYNAMIC_NAME; 209 /* Get existing entry if any */ 210 idx = X509_PURPOSE_get_by_id(id); 211 /* Need a new entry */ 212 if (idx == -1) { 213 if (!(ptmp = OPENSSL_malloc(sizeof(X509_PURPOSE)))) { 214 X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE); 215 return 0; 216 } 217 ptmp->flags = X509_PURPOSE_DYNAMIC; 218 } else 219 ptmp = X509_PURPOSE_get0(idx); 220 221 /* OPENSSL_free existing name if dynamic */ 222 if (ptmp->flags & X509_PURPOSE_DYNAMIC_NAME) { 223 OPENSSL_free(ptmp->name); 224 OPENSSL_free(ptmp->sname); 225 } 226 /* dup supplied name */ 227 ptmp->name = BUF_strdup(name); 228 ptmp->sname = BUF_strdup(sname); 229 if (!ptmp->name || !ptmp->sname) { 230 X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE); 231 return 0; 232 } 233 /* Keep the dynamic flag of existing entry */ 234 ptmp->flags &= X509_PURPOSE_DYNAMIC; 235 /* Set all other flags */ 236 ptmp->flags |= flags; 237 238 ptmp->purpose = id; 239 ptmp->trust = trust; 240 ptmp->check_purpose = ck; 241 ptmp->usr_data = arg; 242 243 /* If its a new entry manage the dynamic table */ 244 if (idx == -1) { 245 if (!xptable && !(xptable = sk_X509_PURPOSE_new(xp_cmp))) { 246 X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE); 247 return 0; 248 } 249 if (!sk_X509_PURPOSE_push(xptable, ptmp)) { 250 X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE); 251 return 0; 252 } 253 } 254 return 1; 255} 256 257static void xptable_free(X509_PURPOSE *p) 258{ 259 if (!p) 260 return; 261 if (p->flags & X509_PURPOSE_DYNAMIC) { 262 if (p->flags & X509_PURPOSE_DYNAMIC_NAME) { 263 OPENSSL_free(p->name); 264 OPENSSL_free(p->sname); 265 } 266 OPENSSL_free(p); 267 } 268} 269 270void X509_PURPOSE_cleanup(void) 271{ 272 unsigned int i; 273 sk_X509_PURPOSE_pop_free(xptable, xptable_free); 274 for (i = 0; i < X509_PURPOSE_COUNT; i++) 275 xptable_free(xstandard + i); 276 xptable = NULL; 277} 278 279int X509_PURPOSE_get_id(X509_PURPOSE *xp) 280{ 281 return xp->purpose; 282} 283 284char *X509_PURPOSE_get0_name(X509_PURPOSE *xp) 285{ 286 return xp->name; 287} 288 289char *X509_PURPOSE_get0_sname(X509_PURPOSE *xp) 290{ 291 return xp->sname; 292} 293 294int X509_PURPOSE_get_trust(X509_PURPOSE *xp) 295{ 296 return xp->trust; 297} 298 299static int nid_cmp(const int *a, const int *b) 300{ 301 return *a - *b; 302} 303 304DECLARE_OBJ_BSEARCH_CMP_FN(int, int, nid); 305IMPLEMENT_OBJ_BSEARCH_CMP_FN(int, int, nid); 306 307int X509_supported_extension(X509_EXTENSION *ex) 308{ 309 /* 310 * This table is a list of the NIDs of supported extensions: that is 311 * those which are used by the verify process. If an extension is 312 * critical and doesn't appear in this list then the verify process will 313 * normally reject the certificate. The list must be kept in numerical 314 * order because it will be searched using bsearch. 315 */ 316 317 static const int supported_nids[] = { 318 NID_netscape_cert_type, /* 71 */ 319 NID_key_usage, /* 83 */ 320 NID_subject_alt_name, /* 85 */ 321 NID_basic_constraints, /* 87 */ 322 NID_certificate_policies, /* 89 */ 323 NID_crl_distribution_points, /* 103 */ 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 int i; 400 401 CRYPTO_w_lock(CRYPTO_LOCK_X509); 402 if (x->ex_flags & EXFLAG_SET) { 403 CRYPTO_w_unlock(CRYPTO_LOCK_X509); 404 return; 405 } 406 407#ifndef OPENSSL_NO_SHA 408 X509_digest(x, EVP_sha1(), x->sha1_hash, NULL); 409#endif 410 /* V1 should mean no extensions ... */ 411 if (!X509_get_version(x)) 412 x->ex_flags |= EXFLAG_V1; 413 /* Handle basic constraints */ 414 if ((bs = X509_get_ext_d2i(x, NID_basic_constraints, NULL, NULL))) { 415 if (bs->ca) 416 x->ex_flags |= EXFLAG_CA; 417 if (bs->pathlen) { 418 if ((bs->pathlen->type == V_ASN1_NEG_INTEGER) 419 || !bs->ca) { 420 x->ex_flags |= EXFLAG_INVALID; 421 x->ex_pathlen = 0; 422 } else 423 x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen); 424 } else 425 x->ex_pathlen = -1; 426 BASIC_CONSTRAINTS_free(bs); 427 x->ex_flags |= EXFLAG_BCONS; 428 } 429 /* Handle proxy certificates */ 430 if ((pci = X509_get_ext_d2i(x, NID_proxyCertInfo, NULL, NULL))) { 431 if (x->ex_flags & EXFLAG_CA 432 || X509_get_ext_by_NID(x, NID_subject_alt_name, -1) >= 0 433 || X509_get_ext_by_NID(x, NID_issuer_alt_name, -1) >= 0) { 434 x->ex_flags |= EXFLAG_INVALID; 435 } 436 if (pci->pcPathLengthConstraint) { 437 x->ex_pcpathlen = ASN1_INTEGER_get(pci->pcPathLengthConstraint); 438 } else 439 x->ex_pcpathlen = -1; 440 PROXY_CERT_INFO_EXTENSION_free(pci); 441 x->ex_flags |= EXFLAG_PROXY; 442 } 443 /* Handle key usage */ 444 if ((usage = X509_get_ext_d2i(x, NID_key_usage, NULL, 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 } 454 x->ex_xkusage = 0; 455 if ((extusage = X509_get_ext_d2i(x, NID_ext_key_usage, NULL, NULL))) { 456 x->ex_flags |= EXFLAG_XKUSAGE; 457 for (i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) { 458 switch (OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage, i))) { 459 case NID_server_auth: 460 x->ex_xkusage |= XKU_SSL_SERVER; 461 break; 462 463 case NID_client_auth: 464 x->ex_xkusage |= XKU_SSL_CLIENT; 465 break; 466 467 case NID_email_protect: 468 x->ex_xkusage |= XKU_SMIME; 469 break; 470 471 case NID_code_sign: 472 x->ex_xkusage |= XKU_CODE_SIGN; 473 break; 474 475 case NID_ms_sgc: 476 case NID_ns_sgc: 477 x->ex_xkusage |= XKU_SGC; 478 break; 479 480 case NID_OCSP_sign: 481 x->ex_xkusage |= XKU_OCSP_SIGN; 482 break; 483 484 case NID_time_stamp: 485 x->ex_xkusage |= XKU_TIMESTAMP; 486 break; 487 488 case NID_dvcs: 489 x->ex_xkusage |= XKU_DVCS; 490 break; 491 492 case NID_anyExtendedKeyUsage: 493 x->ex_xkusage |= XKU_ANYEKU; 494 break; 495 } 496 } 497 sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free); 498 } 499 500 if ((ns = X509_get_ext_d2i(x, NID_netscape_cert_type, NULL, NULL))) { 501 if (ns->length > 0) 502 x->ex_nscert = ns->data[0]; 503 else 504 x->ex_nscert = 0; 505 x->ex_flags |= EXFLAG_NSCERT; 506 ASN1_BIT_STRING_free(ns); 507 } 508 x->skid = X509_get_ext_d2i(x, NID_subject_key_identifier, NULL, NULL); 509 x->akid = X509_get_ext_d2i(x, NID_authority_key_identifier, NULL, NULL); 510 /* Does subject name match issuer ? */ 511 if (!X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x))) { 512 x->ex_flags |= EXFLAG_SI; 513 /* If SKID matches AKID also indicate self signed */ 514 if (X509_check_akid(x, x->akid) == X509_V_OK && 515 !ku_reject(x, KU_KEY_CERT_SIGN)) 516 x->ex_flags |= EXFLAG_SS; 517 } 518 x->altname = X509_get_ext_d2i(x, NID_subject_alt_name, NULL, NULL); 519 x->nc = X509_get_ext_d2i(x, NID_name_constraints, &i, NULL); 520 if (!x->nc && (i != -1)) 521 x->ex_flags |= EXFLAG_INVALID; 522 setup_crldp(x); 523 524#ifndef OPENSSL_NO_RFC3779 525 x->rfc3779_addr = X509_get_ext_d2i(x, NID_sbgp_ipAddrBlock, NULL, NULL); 526 x->rfc3779_asid = X509_get_ext_d2i(x, NID_sbgp_autonomousSysNum, 527 NULL, NULL); 528#endif 529 for (i = 0; i < X509_get_ext_count(x); i++) { 530 ex = X509_get_ext(x, i); 531 if (OBJ_obj2nid(X509_EXTENSION_get_object(ex)) 532 == NID_freshest_crl) 533 x->ex_flags |= EXFLAG_FRESHEST; 534 if (!X509_EXTENSION_get_critical(ex)) 535 continue; 536 if (!X509_supported_extension(ex)) { 537 x->ex_flags |= EXFLAG_CRITICAL; 538 break; 539 } 540 } 541 x->ex_flags |= EXFLAG_SET; 542 CRYPTO_w_unlock(CRYPTO_LOCK_X509); 543} 544 545/*- 546 * CA checks common to all purposes 547 * return codes: 548 * 0 not a CA 549 * 1 is a CA 550 * 2 basicConstraints absent so "maybe" a CA 551 * 3 basicConstraints absent but self signed V1. 552 * 4 basicConstraints absent but keyUsage present and keyCertSign asserted. 553 */ 554 555static int check_ca(const X509 *x) 556{ 557 /* keyUsage if present should allow cert signing */ 558 if (ku_reject(x, KU_KEY_CERT_SIGN)) 559 return 0; 560 if (x->ex_flags & EXFLAG_BCONS) { 561 if (x->ex_flags & EXFLAG_CA) 562 return 1; 563 /* If basicConstraints says not a CA then say so */ 564 else 565 return 0; 566 } else { 567 /* we support V1 roots for... uh, I don't really know why. */ 568 if ((x->ex_flags & V1_ROOT) == V1_ROOT) 569 return 3; 570 /* 571 * If key usage present it must have certSign so tolerate it 572 */ 573 else if (x->ex_flags & EXFLAG_KUSAGE) 574 return 4; 575 /* Older certificates could have Netscape-specific CA types */ 576 else if (x->ex_flags & EXFLAG_NSCERT && x->ex_nscert & NS_ANY_CA) 577 return 5; 578 /* can this still be regarded a CA certificate? I doubt it */ 579 return 0; 580 } 581} 582 583int X509_check_ca(X509 *x) 584{ 585 x509v3_cache_extensions(x); 586 587 return check_ca(x); 588} 589 590/* Check SSL CA: common checks for SSL client and server */ 591static int check_ssl_ca(const X509 *x) 592{ 593 int ca_ret; 594 ca_ret = check_ca(x); 595 if (!ca_ret) 596 return 0; 597 /* check nsCertType if present */ 598 if (ca_ret != 5 || x->ex_nscert & NS_SSL_CA) 599 return ca_ret; 600 else 601 return 0; 602} 603 604static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, 605 int ca) 606{ 607 if (xku_reject(x, XKU_SSL_CLIENT)) 608 return 0; 609 if (ca) 610 return check_ssl_ca(x); 611 /* We need to do digital signatures or key agreement */ 612 if (ku_reject(x, KU_DIGITAL_SIGNATURE | KU_KEY_AGREEMENT)) 613 return 0; 614 /* nsCertType if present should allow SSL client use */ 615 if (ns_reject(x, NS_SSL_CLIENT)) 616 return 0; 617 return 1; 618} 619 620/* 621 * Key usage needed for TLS/SSL server: digital signature, encipherment or 622 * key agreement. The ssl code can check this more thoroughly for individual 623 * key types. 624 */ 625#define KU_TLS \ 626 KU_DIGITAL_SIGNATURE|KU_KEY_ENCIPHERMENT|KU_KEY_AGREEMENT 627 628static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, 629 int ca) 630{ 631 if (xku_reject(x, XKU_SSL_SERVER | XKU_SGC)) 632 return 0; 633 if (ca) 634 return check_ssl_ca(x); 635 636 if (ns_reject(x, NS_SSL_SERVER)) 637 return 0; 638 if (ku_reject(x, KU_TLS)) 639 return 0; 640 641 return 1; 642 643} 644 645static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, 646 int ca) 647{ 648 int ret; 649 ret = check_purpose_ssl_server(xp, x, ca); 650 if (!ret || ca) 651 return ret; 652 /* We need to encipher or Netscape complains */ 653 if (ku_reject(x, KU_KEY_ENCIPHERMENT)) 654 return 0; 655 return ret; 656} 657 658/* common S/MIME checks */ 659static int purpose_smime(const X509 *x, int ca) 660{ 661 if (xku_reject(x, XKU_SMIME)) 662 return 0; 663 if (ca) { 664 int ca_ret; 665 ca_ret = check_ca(x); 666 if (!ca_ret) 667 return 0; 668 /* check nsCertType if present */ 669 if (ca_ret != 5 || x->ex_nscert & NS_SMIME_CA) 670 return ca_ret; 671 else 672 return 0; 673 } 674 if (x->ex_flags & EXFLAG_NSCERT) { 675 if (x->ex_nscert & NS_SMIME) 676 return 1; 677 /* Workaround for some buggy certificates */ 678 if (x->ex_nscert & NS_SSL_CLIENT) 679 return 2; 680 return 0; 681 } 682 return 1; 683} 684 685static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, 686 int ca) 687{ 688 int ret; 689 ret = purpose_smime(x, ca); 690 if (!ret || ca) 691 return ret; 692 if (ku_reject(x, KU_DIGITAL_SIGNATURE | KU_NON_REPUDIATION)) 693 return 0; 694 return ret; 695} 696 697static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, 698 int ca) 699{ 700 int ret; 701 ret = purpose_smime(x, ca); 702 if (!ret || ca) 703 return ret; 704 if (ku_reject(x, KU_KEY_ENCIPHERMENT)) 705 return 0; 706 return ret; 707} 708 709static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, 710 int ca) 711{ 712 if (ca) { 713 int ca_ret; 714 if ((ca_ret = check_ca(x)) != 2) 715 return ca_ret; 716 else 717 return 0; 718 } 719 if (ku_reject(x, KU_CRL_SIGN)) 720 return 0; 721 return 1; 722} 723 724/* 725 * OCSP helper: this is *not* a full OCSP check. It just checks that each CA 726 * is valid. Additional checks must be made on the chain. 727 */ 728 729static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca) 730{ 731 /* 732 * Must be a valid CA. Should we really support the "I don't know" value 733 * (2)? 734 */ 735 if (ca) 736 return check_ca(x); 737 /* leaf certificate is checked in OCSP_verify() */ 738 return 1; 739} 740 741static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x, 742 int ca) 743{ 744 int i_ext; 745 746 /* If ca is true we must return if this is a valid CA certificate. */ 747 if (ca) 748 return check_ca(x); 749 750 /* 751 * Check the optional key usage field: 752 * if Key Usage is present, it must be one of digitalSignature 753 * and/or nonRepudiation (other values are not consistent and shall 754 * be rejected). 755 */ 756 if ((x->ex_flags & EXFLAG_KUSAGE) 757 && ((x->ex_kusage & ~(KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE)) || 758 !(x->ex_kusage & (KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE)))) 759 return 0; 760 761 /* Only time stamp key usage is permitted and it's required. */ 762 if (!(x->ex_flags & EXFLAG_XKUSAGE) || x->ex_xkusage != XKU_TIMESTAMP) 763 return 0; 764 765 /* Extended Key Usage MUST be critical */ 766 i_ext = X509_get_ext_by_NID((X509 *)x, NID_ext_key_usage, -1); 767 if (i_ext >= 0) { 768 X509_EXTENSION *ext = X509_get_ext((X509 *)x, i_ext); 769 if (!X509_EXTENSION_get_critical(ext)) 770 return 0; 771 } 772 773 return 1; 774} 775 776static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca) 777{ 778 return 1; 779} 780 781/*- 782 * Various checks to see if one certificate issued the second. 783 * This can be used to prune a set of possible issuer certificates 784 * which have been looked up using some simple method such as by 785 * subject name. 786 * These are: 787 * 1. Check issuer_name(subject) == subject_name(issuer) 788 * 2. If akid(subject) exists check it matches issuer 789 * 3. If key_usage(issuer) exists check it supports certificate signing 790 * returns 0 for OK, positive for reason for mismatch, reasons match 791 * codes for X509_verify_cert() 792 */ 793 794int X509_check_issued(X509 *issuer, X509 *subject) 795{ 796 if (X509_NAME_cmp(X509_get_subject_name(issuer), 797 X509_get_issuer_name(subject))) 798 return X509_V_ERR_SUBJECT_ISSUER_MISMATCH; 799 800 x509v3_cache_extensions(issuer); 801 x509v3_cache_extensions(subject); 802 803 if (subject->akid) { 804 int ret = X509_check_akid(issuer, subject->akid); 805 if (ret != X509_V_OK) 806 return ret; 807 } 808 809 if (subject->ex_flags & EXFLAG_PROXY) { 810 if (ku_reject(issuer, KU_DIGITAL_SIGNATURE)) 811 return X509_V_ERR_KEYUSAGE_NO_DIGITAL_SIGNATURE; 812 } else if (ku_reject(issuer, KU_KEY_CERT_SIGN)) 813 return X509_V_ERR_KEYUSAGE_NO_CERTSIGN; 814 return X509_V_OK; 815} 816 817int X509_check_akid(X509 *issuer, AUTHORITY_KEYID *akid) 818{ 819 820 if (!akid) 821 return X509_V_OK; 822 823 /* Check key ids (if present) */ 824 if (akid->keyid && issuer->skid && 825 ASN1_OCTET_STRING_cmp(akid->keyid, issuer->skid)) 826 return X509_V_ERR_AKID_SKID_MISMATCH; 827 /* Check serial number */ 828 if (akid->serial && 829 ASN1_INTEGER_cmp(X509_get_serialNumber(issuer), akid->serial)) 830 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH; 831 /* Check issuer name */ 832 if (akid->issuer) { 833 /* 834 * Ugh, for some peculiar reason AKID includes SEQUENCE OF 835 * GeneralName. So look for a DirName. There may be more than one but 836 * we only take any notice of the first. 837 */ 838 GENERAL_NAMES *gens; 839 GENERAL_NAME *gen; 840 X509_NAME *nm = NULL; 841 int i; 842 gens = akid->issuer; 843 for (i = 0; i < sk_GENERAL_NAME_num(gens); i++) { 844 gen = sk_GENERAL_NAME_value(gens, i); 845 if (gen->type == GEN_DIRNAME) { 846 nm = gen->d.dirn; 847 break; 848 } 849 } 850 if (nm && X509_NAME_cmp(nm, X509_get_issuer_name(issuer))) 851 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH; 852 } 853 return X509_V_OK; 854} 855