1 /* $OpenBSD: x509_purp.c,v 1.13 2021/11/04 23:52:34 beck 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_lcl.h" 70 71 #define V1_ROOT (EXFLAG_V1|EXFLAG_SS) 72 #define ku_reject(x, usage) \ 73 (((x)->ex_flags & EXFLAG_KUSAGE) && !((x)->ex_kusage & (usage))) 74 #define xku_reject(x, usage) \ 75 (((x)->ex_flags & EXFLAG_XKUSAGE) && !((x)->ex_xkusage & (usage))) 76 #define ns_reject(x, usage) \ 77 (((x)->ex_flags & EXFLAG_NSCERT) && !((x)->ex_nscert & (usage))) 78 79 void x509v3_cache_extensions(X509 *x); 80 81 static int check_ssl_ca(const X509 *x); 82 static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, 83 int ca); 84 static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, 85 int ca); 86 static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, 87 int ca); 88 static int purpose_smime(const X509 *x, int ca); 89 static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, 90 int ca); 91 static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, 92 int ca); 93 static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, 94 int ca); 95 static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x, 96 int ca); 97 static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca); 98 static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca); 99 100 static int xp_cmp(const X509_PURPOSE * const *a, const X509_PURPOSE * const *b); 101 static void xptable_free(X509_PURPOSE *p); 102 103 static X509_PURPOSE xstandard[] = { 104 {X509_PURPOSE_SSL_CLIENT, X509_TRUST_SSL_CLIENT, 0, check_purpose_ssl_client, "SSL client", "sslclient", NULL}, 105 {X509_PURPOSE_SSL_SERVER, X509_TRUST_SSL_SERVER, 0, check_purpose_ssl_server, "SSL server", "sslserver", NULL}, 106 {X509_PURPOSE_NS_SSL_SERVER, X509_TRUST_SSL_SERVER, 0, check_purpose_ns_ssl_server, "Netscape SSL server", "nssslserver", NULL}, 107 {X509_PURPOSE_SMIME_SIGN, X509_TRUST_EMAIL, 0, check_purpose_smime_sign, "S/MIME signing", "smimesign", NULL}, 108 {X509_PURPOSE_SMIME_ENCRYPT, X509_TRUST_EMAIL, 0, check_purpose_smime_encrypt, "S/MIME encryption", "smimeencrypt", NULL}, 109 {X509_PURPOSE_CRL_SIGN, X509_TRUST_COMPAT, 0, check_purpose_crl_sign, "CRL signing", "crlsign", NULL}, 110 {X509_PURPOSE_ANY, X509_TRUST_DEFAULT, 0, no_check, "Any Purpose", "any", NULL}, 111 {X509_PURPOSE_OCSP_HELPER, X509_TRUST_COMPAT, 0, ocsp_helper, "OCSP helper", "ocsphelper", NULL}, 112 {X509_PURPOSE_TIMESTAMP_SIGN, X509_TRUST_TSA, 0, check_purpose_timestamp_sign, "Time Stamp signing", "timestampsign", NULL}, 113 }; 114 115 #define X509_PURPOSE_COUNT (sizeof(xstandard)/sizeof(X509_PURPOSE)) 116 117 static STACK_OF(X509_PURPOSE) *xptable = NULL; 118 119 static int 120 xp_cmp(const X509_PURPOSE * const *a, const X509_PURPOSE * const *b) 121 { 122 return (*a)->purpose - (*b)->purpose; 123 } 124 125 /* As much as I'd like to make X509_check_purpose use a "const" X509* 126 * I really can't because it does recalculate hashes and do other non-const 127 * things. */ 128 int 129 X509_check_purpose(X509 *x, int id, int ca) 130 { 131 int idx; 132 const X509_PURPOSE *pt; 133 134 if (!(x->ex_flags & EXFLAG_SET)) { 135 CRYPTO_w_lock(CRYPTO_LOCK_X509); 136 x509v3_cache_extensions(x); 137 CRYPTO_w_unlock(CRYPTO_LOCK_X509); 138 if (x->ex_flags & EXFLAG_INVALID) 139 return -1; 140 } 141 if (id == -1) 142 return 1; 143 idx = X509_PURPOSE_get_by_id(id); 144 if (idx == -1) 145 return -1; 146 pt = X509_PURPOSE_get0(idx); 147 return pt->check_purpose(pt, x, ca); 148 } 149 150 int 151 X509_PURPOSE_set(int *p, int purpose) 152 { 153 if (X509_PURPOSE_get_by_id(purpose) == -1) { 154 X509V3error(X509V3_R_INVALID_PURPOSE); 155 return 0; 156 } 157 *p = purpose; 158 return 1; 159 } 160 161 int 162 X509_PURPOSE_get_count(void) 163 { 164 if (!xptable) 165 return X509_PURPOSE_COUNT; 166 return sk_X509_PURPOSE_num(xptable) + X509_PURPOSE_COUNT; 167 } 168 169 X509_PURPOSE * 170 X509_PURPOSE_get0(int idx) 171 { 172 if (idx < 0) 173 return NULL; 174 if (idx < (int)X509_PURPOSE_COUNT) 175 return xstandard + idx; 176 return sk_X509_PURPOSE_value(xptable, idx - X509_PURPOSE_COUNT); 177 } 178 179 int 180 X509_PURPOSE_get_by_sname(const char *sname) 181 { 182 int i; 183 X509_PURPOSE *xptmp; 184 185 for (i = 0; i < X509_PURPOSE_get_count(); i++) { 186 xptmp = X509_PURPOSE_get0(i); 187 if (!strcmp(xptmp->sname, sname)) 188 return i; 189 } 190 return -1; 191 } 192 193 int 194 X509_PURPOSE_get_by_id(int purpose) 195 { 196 X509_PURPOSE tmp; 197 int idx; 198 199 if ((purpose >= X509_PURPOSE_MIN) && (purpose <= X509_PURPOSE_MAX)) 200 return purpose - X509_PURPOSE_MIN; 201 tmp.purpose = purpose; 202 if (!xptable) 203 return -1; 204 idx = sk_X509_PURPOSE_find(xptable, &tmp); 205 if (idx == -1) 206 return -1; 207 return idx + X509_PURPOSE_COUNT; 208 } 209 210 int 211 X509_PURPOSE_add(int id, int trust, int flags, 212 int (*ck)(const X509_PURPOSE *, const X509 *, int), const char *name, 213 const char *sname, void *arg) 214 { 215 int idx; 216 X509_PURPOSE *ptmp; 217 char *name_dup, *sname_dup; 218 219 name_dup = sname_dup = NULL; 220 221 if (name == NULL || sname == NULL) { 222 X509V3error(X509V3_R_INVALID_NULL_ARGUMENT); 223 return 0; 224 } 225 226 /* This is set according to what we change: application can't set it */ 227 flags &= ~X509_PURPOSE_DYNAMIC; 228 /* This will always be set for application modified trust entries */ 229 flags |= X509_PURPOSE_DYNAMIC_NAME; 230 /* Get existing entry if any */ 231 idx = X509_PURPOSE_get_by_id(id); 232 /* Need a new entry */ 233 if (idx == -1) { 234 if ((ptmp = malloc(sizeof(X509_PURPOSE))) == NULL) { 235 X509V3error(ERR_R_MALLOC_FAILURE); 236 return 0; 237 } 238 ptmp->flags = X509_PURPOSE_DYNAMIC; 239 } else 240 ptmp = X509_PURPOSE_get0(idx); 241 242 if ((name_dup = strdup(name)) == NULL) 243 goto err; 244 if ((sname_dup = strdup(sname)) == NULL) 245 goto err; 246 247 /* free existing name if dynamic */ 248 if (ptmp->flags & X509_PURPOSE_DYNAMIC_NAME) { 249 free(ptmp->name); 250 free(ptmp->sname); 251 } 252 /* dup supplied name */ 253 ptmp->name = name_dup; 254 ptmp->sname = sname_dup; 255 /* Keep the dynamic flag of existing entry */ 256 ptmp->flags &= X509_PURPOSE_DYNAMIC; 257 /* Set all other flags */ 258 ptmp->flags |= flags; 259 260 ptmp->purpose = id; 261 ptmp->trust = trust; 262 ptmp->check_purpose = ck; 263 ptmp->usr_data = arg; 264 265 /* If its a new entry manage the dynamic table */ 266 if (idx == -1) { 267 if (xptable == NULL && 268 (xptable = sk_X509_PURPOSE_new(xp_cmp)) == NULL) 269 goto err; 270 if (sk_X509_PURPOSE_push(xptable, ptmp) == 0) 271 goto err; 272 } 273 return 1; 274 275 err: 276 free(name_dup); 277 free(sname_dup); 278 if (idx == -1) 279 free(ptmp); 280 X509V3error(ERR_R_MALLOC_FAILURE); 281 return 0; 282 } 283 284 static void 285 xptable_free(X509_PURPOSE *p) 286 { 287 if (!p) 288 return; 289 if (p->flags & X509_PURPOSE_DYNAMIC) { 290 if (p->flags & X509_PURPOSE_DYNAMIC_NAME) { 291 free(p->name); 292 free(p->sname); 293 } 294 free(p); 295 } 296 } 297 298 void 299 X509_PURPOSE_cleanup(void) 300 { 301 sk_X509_PURPOSE_pop_free(xptable, xptable_free); 302 xptable = NULL; 303 } 304 305 int 306 X509_PURPOSE_get_id(const X509_PURPOSE *xp) 307 { 308 return xp->purpose; 309 } 310 311 char * 312 X509_PURPOSE_get0_name(const X509_PURPOSE *xp) 313 { 314 return xp->name; 315 } 316 317 char * 318 X509_PURPOSE_get0_sname(const X509_PURPOSE *xp) 319 { 320 return xp->sname; 321 } 322 323 int 324 X509_PURPOSE_get_trust(const X509_PURPOSE *xp) 325 { 326 return xp->trust; 327 } 328 329 static int 330 nid_cmp(const int *a, const int *b) 331 { 332 return *a - *b; 333 } 334 335 static int nid_cmp_BSEARCH_CMP_FN(const void *, const void *); 336 static int nid_cmp(int const *, int const *); 337 static int *OBJ_bsearch_nid(int *key, int const *base, int num); 338 339 static int 340 nid_cmp_BSEARCH_CMP_FN(const void *a_, const void *b_) 341 { 342 int const *a = a_; 343 int const *b = b_; 344 return nid_cmp(a, b); 345 } 346 347 static int * 348 OBJ_bsearch_nid(int *key, int const *base, int num) 349 { 350 return (int *)OBJ_bsearch_(key, base, num, sizeof(int), 351 nid_cmp_BSEARCH_CMP_FN); 352 } 353 354 int 355 X509_supported_extension(X509_EXTENSION *ex) 356 { 357 /* This table is a list of the NIDs of supported extensions: 358 * that is those which are used by the verify process. If 359 * an extension is critical and doesn't appear in this list 360 * then the verify process will normally reject the certificate. 361 * The list must be kept in numerical order because it will be 362 * searched using bsearch. 363 */ 364 365 static const int supported_nids[] = { 366 NID_netscape_cert_type, /* 71 */ 367 NID_key_usage, /* 83 */ 368 NID_subject_alt_name, /* 85 */ 369 NID_basic_constraints, /* 87 */ 370 NID_certificate_policies, /* 89 */ 371 NID_ext_key_usage, /* 126 */ 372 #ifndef OPENSSL_NO_RFC3779 373 NID_sbgp_ipAddrBlock, /* 290 */ 374 NID_sbgp_autonomousSysNum, /* 291 */ 375 #endif 376 NID_policy_constraints, /* 401 */ 377 NID_proxyCertInfo, /* 663 */ 378 NID_name_constraints, /* 666 */ 379 NID_policy_mappings, /* 747 */ 380 NID_inhibit_any_policy /* 748 */ 381 }; 382 383 int ex_nid = OBJ_obj2nid(X509_EXTENSION_get_object(ex)); 384 385 if (ex_nid == NID_undef) 386 return 0; 387 388 if (OBJ_bsearch_nid(&ex_nid, supported_nids, 389 sizeof(supported_nids) / sizeof(int))) 390 return 1; 391 return 0; 392 } 393 394 static void 395 setup_dp(X509 *x, DIST_POINT *dp) 396 { 397 X509_NAME *iname = NULL; 398 int i; 399 400 if (dp->reasons) { 401 if (dp->reasons->length > 0) 402 dp->dp_reasons = dp->reasons->data[0]; 403 if (dp->reasons->length > 1) 404 dp->dp_reasons |= (dp->reasons->data[1] << 8); 405 dp->dp_reasons &= CRLDP_ALL_REASONS; 406 } else 407 dp->dp_reasons = CRLDP_ALL_REASONS; 408 if (!dp->distpoint || (dp->distpoint->type != 1)) 409 return; 410 for (i = 0; i < sk_GENERAL_NAME_num(dp->CRLissuer); i++) { 411 GENERAL_NAME *gen = sk_GENERAL_NAME_value(dp->CRLissuer, i); 412 if (gen->type == GEN_DIRNAME) { 413 iname = gen->d.directoryName; 414 break; 415 } 416 } 417 if (!iname) 418 iname = X509_get_issuer_name(x); 419 420 DIST_POINT_set_dpname(dp->distpoint, iname); 421 422 } 423 424 static void 425 setup_crldp(X509 *x) 426 { 427 int i; 428 429 x->crldp = X509_get_ext_d2i(x, NID_crl_distribution_points, &i, NULL); 430 if (x->crldp == NULL && i != -1) { 431 x->ex_flags |= EXFLAG_INVALID; 432 return; 433 } 434 435 for (i = 0; i < sk_DIST_POINT_num(x->crldp); i++) 436 setup_dp(x, sk_DIST_POINT_value(x->crldp, i)); 437 } 438 439 void 440 x509v3_cache_extensions(X509 *x) 441 { 442 BASIC_CONSTRAINTS *bs; 443 PROXY_CERT_INFO_EXTENSION *pci; 444 ASN1_BIT_STRING *usage; 445 ASN1_BIT_STRING *ns; 446 EXTENDED_KEY_USAGE *extusage; 447 X509_EXTENSION *ex; 448 int i; 449 450 if (x->ex_flags & EXFLAG_SET) 451 return; 452 453 X509_digest(x, X509_CERT_HASH_EVP, x->hash, NULL); 454 455 /* V1 should mean no extensions ... */ 456 if (!X509_get_version(x)) 457 x->ex_flags |= EXFLAG_V1; 458 459 /* Handle basic constraints */ 460 if ((bs = X509_get_ext_d2i(x, NID_basic_constraints, &i, NULL))) { 461 if (bs->ca) 462 x->ex_flags |= EXFLAG_CA; 463 if (bs->pathlen) { 464 if ((bs->pathlen->type == V_ASN1_NEG_INTEGER) || 465 !bs->ca) { 466 x->ex_flags |= EXFLAG_INVALID; 467 x->ex_pathlen = 0; 468 } else 469 x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen); 470 } else 471 x->ex_pathlen = -1; 472 BASIC_CONSTRAINTS_free(bs); 473 x->ex_flags |= EXFLAG_BCONS; 474 } else if (i != -1) { 475 x->ex_flags |= EXFLAG_INVALID; 476 } 477 478 /* Handle proxy certificates */ 479 if ((pci = X509_get_ext_d2i(x, NID_proxyCertInfo, &i, NULL))) { 480 if (x->ex_flags & EXFLAG_CA || 481 X509_get_ext_by_NID(x, NID_subject_alt_name, -1) >= 0 || 482 X509_get_ext_by_NID(x, NID_issuer_alt_name, -1) >= 0) { 483 x->ex_flags |= EXFLAG_INVALID; 484 } 485 if (pci->pcPathLengthConstraint) { 486 if (pci->pcPathLengthConstraint->type == 487 V_ASN1_NEG_INTEGER) { 488 x->ex_flags |= EXFLAG_INVALID; 489 x->ex_pcpathlen = 0; 490 } else 491 x->ex_pcpathlen = 492 ASN1_INTEGER_get(pci-> 493 pcPathLengthConstraint); 494 } else 495 x->ex_pcpathlen = -1; 496 PROXY_CERT_INFO_EXTENSION_free(pci); 497 x->ex_flags |= EXFLAG_PROXY; 498 } else if (i != -1) { 499 x->ex_flags |= EXFLAG_INVALID; 500 } 501 502 /* Handle key usage */ 503 if ((usage = X509_get_ext_d2i(x, NID_key_usage, &i, NULL))) { 504 if (usage->length > 0) { 505 x->ex_kusage = usage->data[0]; 506 if (usage->length > 1) 507 x->ex_kusage |= usage->data[1] << 8; 508 } else 509 x->ex_kusage = 0; 510 x->ex_flags |= EXFLAG_KUSAGE; 511 ASN1_BIT_STRING_free(usage); 512 } else if (i != -1) { 513 x->ex_flags |= EXFLAG_INVALID; 514 } 515 516 x->ex_xkusage = 0; 517 if ((extusage = X509_get_ext_d2i(x, NID_ext_key_usage, &i, NULL))) { 518 x->ex_flags |= EXFLAG_XKUSAGE; 519 for (i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) { 520 switch (OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage, i))) { 521 case NID_server_auth: 522 x->ex_xkusage |= XKU_SSL_SERVER; 523 break; 524 525 case NID_client_auth: 526 x->ex_xkusage |= XKU_SSL_CLIENT; 527 break; 528 529 case NID_email_protect: 530 x->ex_xkusage |= XKU_SMIME; 531 break; 532 533 case NID_code_sign: 534 x->ex_xkusage |= XKU_CODE_SIGN; 535 break; 536 537 case NID_ms_sgc: 538 case NID_ns_sgc: 539 x->ex_xkusage |= XKU_SGC; 540 break; 541 542 case NID_OCSP_sign: 543 x->ex_xkusage |= XKU_OCSP_SIGN; 544 break; 545 546 case NID_time_stamp: 547 x->ex_xkusage |= XKU_TIMESTAMP; 548 break; 549 550 case NID_dvcs: 551 x->ex_xkusage |= XKU_DVCS; 552 break; 553 554 case NID_anyExtendedKeyUsage: 555 x->ex_xkusage |= XKU_ANYEKU; 556 break; 557 } 558 } 559 sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free); 560 } else if (i != -1) { 561 x->ex_flags |= EXFLAG_INVALID; 562 } 563 564 if ((ns = X509_get_ext_d2i(x, NID_netscape_cert_type, &i, NULL))) { 565 if (ns->length > 0) 566 x->ex_nscert = ns->data[0]; 567 else 568 x->ex_nscert = 0; 569 x->ex_flags |= EXFLAG_NSCERT; 570 ASN1_BIT_STRING_free(ns); 571 } else if (i != -1) { 572 x->ex_flags |= EXFLAG_INVALID; 573 } 574 575 x->skid = X509_get_ext_d2i(x, NID_subject_key_identifier, &i, NULL); 576 if (x->skid == NULL && i != -1) 577 x->ex_flags |= EXFLAG_INVALID; 578 x->akid = X509_get_ext_d2i(x, NID_authority_key_identifier, &i, NULL); 579 if (x->akid == NULL && i != -1) 580 x->ex_flags |= EXFLAG_INVALID; 581 582 /* Does subject name match issuer? */ 583 if (!X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x))) { 584 x->ex_flags |= EXFLAG_SI; 585 /* If SKID matches AKID also indicate self signed. */ 586 if (X509_check_akid(x, x->akid) == X509_V_OK && 587 !ku_reject(x, KU_KEY_CERT_SIGN)) 588 x->ex_flags |= EXFLAG_SS; 589 } 590 591 x->altname = X509_get_ext_d2i(x, NID_subject_alt_name, &i, NULL); 592 if (x->altname == NULL && i != -1) 593 x->ex_flags |= EXFLAG_INVALID; 594 x->nc = X509_get_ext_d2i(x, NID_name_constraints, &i, NULL); 595 if (!x->nc && (i != -1)) 596 x->ex_flags |= EXFLAG_INVALID; 597 setup_crldp(x); 598 599 #ifndef OPENSSL_NO_RFC3779 600 x->rfc3779_addr = X509_get_ext_d2i(x, NID_sbgp_ipAddrBlock, &i, NULL); 601 if (x->rfc3779_addr == NULL && i != -1) 602 x->ex_flags |= EXFLAG_INVALID; 603 x->rfc3779_asid = X509_get_ext_d2i(x, NID_sbgp_autonomousSysNum, &i, NULL); 604 if (x->rfc3779_asid == NULL && i != -1) 605 x->ex_flags |= EXFLAG_INVALID; 606 #endif 607 608 for (i = 0; i < X509_get_ext_count(x); i++) { 609 ex = X509_get_ext(x, i); 610 if (OBJ_obj2nid(X509_EXTENSION_get_object(ex)) == 611 NID_freshest_crl) 612 x->ex_flags |= EXFLAG_FRESHEST; 613 if (!X509_EXTENSION_get_critical(ex)) 614 continue; 615 if (!X509_supported_extension(ex)) { 616 x->ex_flags |= EXFLAG_CRITICAL; 617 break; 618 } 619 } 620 621 x509_verify_cert_info_populate(x); 622 623 x->ex_flags |= EXFLAG_SET; 624 } 625 626 /* CA checks common to all purposes 627 * return codes: 628 * 0 not a CA 629 * 1 is a CA 630 * 2 basicConstraints absent so "maybe" a CA 631 * 3 basicConstraints absent but self signed V1. 632 * 4 basicConstraints absent but keyUsage present and keyCertSign asserted. 633 */ 634 635 static int 636 check_ca(const X509 *x) 637 { 638 /* keyUsage if present should allow cert signing */ 639 if (ku_reject(x, KU_KEY_CERT_SIGN)) 640 return 0; 641 if (x->ex_flags & EXFLAG_BCONS) { 642 if (x->ex_flags & EXFLAG_CA) 643 return 1; 644 /* If basicConstraints says not a CA then say so */ 645 else 646 return 0; 647 } else { 648 /* we support V1 roots for... uh, I don't really know why. */ 649 if ((x->ex_flags & V1_ROOT) == V1_ROOT) 650 return 3; 651 /* If key usage present it must have certSign so tolerate it */ 652 else if (x->ex_flags & EXFLAG_KUSAGE) 653 return 4; 654 /* Older certificates could have Netscape-specific CA types */ 655 else if (x->ex_flags & EXFLAG_NSCERT && 656 x->ex_nscert & NS_ANY_CA) 657 return 5; 658 /* can this still be regarded a CA certificate? I doubt it */ 659 return 0; 660 } 661 } 662 663 int 664 X509_check_ca(X509 *x) 665 { 666 if (!(x->ex_flags & EXFLAG_SET)) { 667 CRYPTO_w_lock(CRYPTO_LOCK_X509); 668 x509v3_cache_extensions(x); 669 CRYPTO_w_unlock(CRYPTO_LOCK_X509); 670 if (x->ex_flags & EXFLAG_INVALID) 671 return X509_V_ERR_UNSPECIFIED; 672 } 673 674 return check_ca(x); 675 } 676 677 /* Check SSL CA: common checks for SSL client and server */ 678 static int 679 check_ssl_ca(const X509 *x) 680 { 681 int ca_ret; 682 683 ca_ret = check_ca(x); 684 if (!ca_ret) 685 return 0; 686 /* check nsCertType if present */ 687 if (ca_ret != 5 || x->ex_nscert & NS_SSL_CA) 688 return ca_ret; 689 else 690 return 0; 691 } 692 693 static int 694 check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, int ca) 695 { 696 if (xku_reject(x, XKU_SSL_CLIENT)) 697 return 0; 698 if (ca) 699 return check_ssl_ca(x); 700 /* We need to do digital signatures with it */ 701 if (ku_reject(x, KU_DIGITAL_SIGNATURE)) 702 return 0; 703 /* nsCertType if present should allow SSL client use */ 704 if (ns_reject(x, NS_SSL_CLIENT)) 705 return 0; 706 return 1; 707 } 708 709 static int 710 check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca) 711 { 712 if (xku_reject(x, XKU_SSL_SERVER|XKU_SGC)) 713 return 0; 714 if (ca) 715 return check_ssl_ca(x); 716 717 if (ns_reject(x, NS_SSL_SERVER)) 718 return 0; 719 /* Now as for keyUsage: we'll at least need to sign OR encipher */ 720 if (ku_reject(x, KU_DIGITAL_SIGNATURE|KU_KEY_ENCIPHERMENT)) 721 return 0; 722 723 return 1; 724 } 725 726 static int 727 check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca) 728 { 729 int ret; 730 731 ret = check_purpose_ssl_server(xp, x, ca); 732 if (!ret || ca) 733 return ret; 734 /* We need to encipher or Netscape complains */ 735 if (ku_reject(x, KU_KEY_ENCIPHERMENT)) 736 return 0; 737 return ret; 738 } 739 740 /* common S/MIME checks */ 741 static int 742 purpose_smime(const X509 *x, int ca) 743 { 744 if (xku_reject(x, XKU_SMIME)) 745 return 0; 746 if (ca) { 747 int ca_ret; 748 ca_ret = check_ca(x); 749 if (!ca_ret) 750 return 0; 751 /* check nsCertType if present */ 752 if (ca_ret != 5 || x->ex_nscert & NS_SMIME_CA) 753 return ca_ret; 754 else 755 return 0; 756 } 757 if (x->ex_flags & EXFLAG_NSCERT) { 758 if (x->ex_nscert & NS_SMIME) 759 return 1; 760 /* Workaround for some buggy certificates */ 761 if (x->ex_nscert & NS_SSL_CLIENT) 762 return 2; 763 return 0; 764 } 765 return 1; 766 } 767 768 static int 769 check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, int ca) 770 { 771 int ret; 772 773 ret = purpose_smime(x, ca); 774 if (!ret || ca) 775 return ret; 776 if (ku_reject(x, KU_DIGITAL_SIGNATURE|KU_NON_REPUDIATION)) 777 return 0; 778 return ret; 779 } 780 781 static int 782 check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, int ca) 783 { 784 int ret; 785 786 ret = purpose_smime(x, ca); 787 if (!ret || ca) 788 return ret; 789 if (ku_reject(x, KU_KEY_ENCIPHERMENT)) 790 return 0; 791 return ret; 792 } 793 794 static int 795 check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, int ca) 796 { 797 if (ca) { 798 int ca_ret; 799 if ((ca_ret = check_ca(x)) != 2) 800 return ca_ret; 801 else 802 return 0; 803 } 804 if (ku_reject(x, KU_CRL_SIGN)) 805 return 0; 806 return 1; 807 } 808 809 /* OCSP helper: this is *not* a full OCSP check. It just checks that 810 * each CA is valid. Additional checks must be made on the chain. 811 */ 812 static int 813 ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca) 814 { 815 /* Must be a valid CA. Should we really support the "I don't know" 816 value (2)? */ 817 if (ca) 818 return check_ca(x); 819 /* leaf certificate is checked in OCSP_verify() */ 820 return 1; 821 } 822 823 static int 824 check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x, int ca) 825 { 826 int i_ext; 827 828 /* If ca is true we must return if this is a valid CA certificate. */ 829 if (ca) 830 return check_ca(x); 831 832 /* 833 * Check the optional key usage field: 834 * if Key Usage is present, it must be one of digitalSignature 835 * and/or nonRepudiation (other values are not consistent and shall 836 * be rejected). 837 */ 838 if ((x->ex_flags & EXFLAG_KUSAGE) && 839 ((x->ex_kusage & ~(KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE)) || 840 !(x->ex_kusage & (KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE)))) 841 return 0; 842 843 /* Only time stamp key usage is permitted and it's required. */ 844 if (!(x->ex_flags & EXFLAG_XKUSAGE) || x->ex_xkusage != XKU_TIMESTAMP) 845 return 0; 846 847 /* Extended Key Usage MUST be critical */ 848 i_ext = X509_get_ext_by_NID((X509 *) x, NID_ext_key_usage, -1); 849 if (i_ext >= 0) { 850 X509_EXTENSION *ext = X509_get_ext((X509 *) x, i_ext); 851 if (!X509_EXTENSION_get_critical(ext)) 852 return 0; 853 } 854 855 return 1; 856 } 857 858 static int 859 no_check(const X509_PURPOSE *xp, const X509 *x, int ca) 860 { 861 return 1; 862 } 863 864 /* Various checks to see if one certificate issued the second. 865 * This can be used to prune a set of possible issuer certificates 866 * which have been looked up using some simple method such as by 867 * subject name. 868 * These are: 869 * 1. Check issuer_name(subject) == subject_name(issuer) 870 * 2. If akid(subject) exists check it matches issuer 871 * 3. If key_usage(issuer) exists check it supports certificate signing 872 * returns 0 for OK, positive for reason for mismatch, reasons match 873 * codes for X509_verify_cert() 874 */ 875 876 int 877 X509_check_issued(X509 *issuer, X509 *subject) 878 { 879 if (X509_NAME_cmp(X509_get_subject_name(issuer), 880 X509_get_issuer_name(subject))) 881 return X509_V_ERR_SUBJECT_ISSUER_MISMATCH; 882 if (!(issuer->ex_flags & EXFLAG_SET)) { 883 CRYPTO_w_lock(CRYPTO_LOCK_X509); 884 x509v3_cache_extensions(issuer); 885 CRYPTO_w_unlock(CRYPTO_LOCK_X509); 886 } 887 if (issuer->ex_flags & EXFLAG_INVALID) 888 return X509_V_ERR_UNSPECIFIED; 889 if (!(subject->ex_flags & EXFLAG_SET)) { 890 CRYPTO_w_lock(CRYPTO_LOCK_X509); 891 x509v3_cache_extensions(subject); 892 CRYPTO_w_unlock(CRYPTO_LOCK_X509); 893 } 894 if (subject->ex_flags & EXFLAG_INVALID) 895 return X509_V_ERR_UNSPECIFIED; 896 897 if (subject->akid) { 898 int ret = X509_check_akid(issuer, subject->akid); 899 if (ret != X509_V_OK) 900 return ret; 901 } 902 903 if (subject->ex_flags & EXFLAG_PROXY) { 904 if (ku_reject(issuer, KU_DIGITAL_SIGNATURE)) 905 return X509_V_ERR_KEYUSAGE_NO_DIGITAL_SIGNATURE; 906 } else if (ku_reject(issuer, KU_KEY_CERT_SIGN)) 907 return X509_V_ERR_KEYUSAGE_NO_CERTSIGN; 908 return X509_V_OK; 909 } 910 911 int 912 X509_check_akid(X509 *issuer, AUTHORITY_KEYID *akid) 913 { 914 if (!akid) 915 return X509_V_OK; 916 917 /* Check key ids (if present) */ 918 if (akid->keyid && issuer->skid && 919 ASN1_OCTET_STRING_cmp(akid->keyid, issuer->skid) ) 920 return X509_V_ERR_AKID_SKID_MISMATCH; 921 /* Check serial number */ 922 if (akid->serial && 923 ASN1_INTEGER_cmp(X509_get_serialNumber(issuer), akid->serial)) 924 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH; 925 /* Check issuer name */ 926 if (akid->issuer) { 927 /* Ugh, for some peculiar reason AKID includes 928 * SEQUENCE OF GeneralName. So look for a DirName. 929 * There may be more than one but we only take any 930 * notice of the first. 931 */ 932 GENERAL_NAMES *gens; 933 GENERAL_NAME *gen; 934 X509_NAME *nm = NULL; 935 int i; 936 gens = akid->issuer; 937 for (i = 0; i < sk_GENERAL_NAME_num(gens); i++) { 938 gen = sk_GENERAL_NAME_value(gens, i); 939 if (gen->type == GEN_DIRNAME) { 940 nm = gen->d.dirn; 941 break; 942 } 943 } 944 if (nm && X509_NAME_cmp(nm, X509_get_issuer_name(issuer))) 945 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH; 946 } 947 return X509_V_OK; 948 } 949 950 uint32_t 951 X509_get_extension_flags(X509 *x) 952 { 953 /* Call for side-effect of computing hash and caching extensions */ 954 if (X509_check_purpose(x, -1, -1) != 1) 955 return 0; 956 957 return x->ex_flags; 958 } 959 960 uint32_t 961 X509_get_key_usage(X509 *x) 962 { 963 /* Call for side-effect of computing hash and caching extensions */ 964 if (X509_check_purpose(x, -1, -1) != 1) 965 return 0; 966 967 if (x->ex_flags & EXFLAG_KUSAGE) 968 return x->ex_kusage; 969 970 return UINT32_MAX; 971 } 972 973 uint32_t 974 X509_get_extended_key_usage(X509 *x) 975 { 976 /* Call for side-effect of computing hash and caching extensions */ 977 if (X509_check_purpose(x, -1, -1) != 1) 978 return 0; 979 980 if (x->ex_flags & EXFLAG_XKUSAGE) 981 return x->ex_xkusage; 982 983 return UINT32_MAX; 984 } 985