1/* v3_purp.c */ 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#include <stdio.h> 58 59#include <openssl/buf.h> 60#include <openssl/err.h> 61#include <openssl/digest.h> 62#include <openssl/mem.h> 63#include <openssl/obj.h> 64#include <openssl/x509_vfy.h> 65#include <openssl/x509v3.h> 66 67 68static void x509v3_cache_extensions(X509 *x); 69 70static int check_ssl_ca(const X509 *x); 71static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, int ca); 72static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca); 73static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca); 74static int purpose_smime(const X509 *x, int ca); 75static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, int ca); 76static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, int ca); 77static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, int ca); 78static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x, int ca); 79static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca); 80static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca); 81 82static int xp_cmp(const X509_PURPOSE **a, const X509_PURPOSE **b); 83static void xptable_free(X509_PURPOSE *p); 84 85static X509_PURPOSE xstandard[] = { 86 {X509_PURPOSE_SSL_CLIENT, X509_TRUST_SSL_CLIENT, 0, check_purpose_ssl_client, (char *) "SSL client", (char *) "sslclient", NULL}, 87 {X509_PURPOSE_SSL_SERVER, X509_TRUST_SSL_SERVER, 0, check_purpose_ssl_server, (char *) "SSL server", (char *) "sslserver", NULL}, 88 {X509_PURPOSE_NS_SSL_SERVER, X509_TRUST_SSL_SERVER, 0, check_purpose_ns_ssl_server, (char *) "Netscape SSL server", (char *) "nssslserver", NULL}, 89 {X509_PURPOSE_SMIME_SIGN, X509_TRUST_EMAIL, 0, check_purpose_smime_sign, (char *) "S/MIME signing", (char *) "smimesign", NULL}, 90 {X509_PURPOSE_SMIME_ENCRYPT, X509_TRUST_EMAIL, 0, check_purpose_smime_encrypt, (char *) "S/MIME encryption", (char *) "smimeencrypt", NULL}, 91 {X509_PURPOSE_CRL_SIGN, X509_TRUST_COMPAT, 0, check_purpose_crl_sign, (char *) "CRL signing", (char *) "crlsign", NULL}, 92 {X509_PURPOSE_ANY, X509_TRUST_DEFAULT, 0, no_check, (char *) "Any Purpose", (char *) "any", NULL}, 93 {X509_PURPOSE_OCSP_HELPER, X509_TRUST_COMPAT, 0, ocsp_helper, (char *) "OCSP helper", (char *) "ocsphelper", NULL}, 94 {X509_PURPOSE_TIMESTAMP_SIGN, X509_TRUST_TSA, 0, check_purpose_timestamp_sign, (char *) "Time Stamp signing", (char *) "timestampsign", NULL}, 95}; 96 97#define X509_PURPOSE_COUNT (sizeof(xstandard)/sizeof(X509_PURPOSE)) 98 99static STACK_OF(X509_PURPOSE) *xptable = NULL; 100 101static int xp_cmp(const X509_PURPOSE **a, const X509_PURPOSE **b) 102{ 103 return (*a)->purpose - (*b)->purpose; 104} 105 106/* As much as I'd like to make X509_check_purpose use a "const" X509* 107 * I really can't because it does recalculate hashes and do other non-const 108 * things. */ 109int X509_check_purpose(X509 *x, int id, int ca) 110{ 111 int idx; 112 const X509_PURPOSE *pt; 113 if(!(x->ex_flags & EXFLAG_SET)) { 114 CRYPTO_w_lock(CRYPTO_LOCK_X509); 115 x509v3_cache_extensions(x); 116 CRYPTO_w_unlock(CRYPTO_LOCK_X509); 117 } 118 if(id == -1) return 1; 119 idx = X509_PURPOSE_get_by_id(id); 120 if(idx == -1) return -1; 121 pt = X509_PURPOSE_get0(idx); 122 return pt->check_purpose(pt, x, ca); 123} 124 125int X509_PURPOSE_set(int *p, int purpose) 126{ 127 if(X509_PURPOSE_get_by_id(purpose) == -1) { 128 OPENSSL_PUT_ERROR(X509V3, X509_PURPOSE_set, X509V3_R_INVALID_PURPOSE); 129 return 0; 130 } 131 *p = purpose; 132 return 1; 133} 134 135int X509_PURPOSE_get_count(void) 136{ 137 if(!xptable) return X509_PURPOSE_COUNT; 138 return sk_X509_PURPOSE_num(xptable) + X509_PURPOSE_COUNT; 139} 140 141X509_PURPOSE * X509_PURPOSE_get0(int idx) 142{ 143 if(idx < 0) return NULL; 144 if(idx < (int)X509_PURPOSE_COUNT) return xstandard + idx; 145 return sk_X509_PURPOSE_value(xptable, idx - X509_PURPOSE_COUNT); 146} 147 148int X509_PURPOSE_get_by_sname(char *sname) 149{ 150 int i; 151 X509_PURPOSE *xptmp; 152 for(i = 0; i < X509_PURPOSE_get_count(); i++) { 153 xptmp = X509_PURPOSE_get0(i); 154 if(!strcmp(xptmp->sname, sname)) return i; 155 } 156 return -1; 157} 158 159int X509_PURPOSE_get_by_id(int purpose) 160{ 161 X509_PURPOSE tmp; 162 size_t idx; 163 164 if((purpose >= X509_PURPOSE_MIN) && (purpose <= X509_PURPOSE_MAX)) 165 return purpose - X509_PURPOSE_MIN; 166 tmp.purpose = purpose; 167 if(!xptable) return -1; 168 169 if (!sk_X509_PURPOSE_find(xptable, &idx, &tmp)) 170 return -1; 171 return idx + X509_PURPOSE_COUNT; 172} 173 174int X509_PURPOSE_add(int id, int trust, int flags, 175 int (*ck)(const X509_PURPOSE *, const X509 *, int), 176 char *name, char *sname, void *arg) 177{ 178 int idx; 179 X509_PURPOSE *ptmp; 180 /* This is set according to what we change: application can't set it */ 181 flags &= ~X509_PURPOSE_DYNAMIC; 182 /* This will always be set for application modified trust entries */ 183 flags |= X509_PURPOSE_DYNAMIC_NAME; 184 /* Get existing entry if any */ 185 idx = X509_PURPOSE_get_by_id(id); 186 /* Need a new entry */ 187 if(idx == -1) { 188 if(!(ptmp = OPENSSL_malloc(sizeof(X509_PURPOSE)))) { 189 OPENSSL_PUT_ERROR(X509V3, X509_PURPOSE_add, ERR_R_MALLOC_FAILURE); 190 return 0; 191 } 192 ptmp->flags = X509_PURPOSE_DYNAMIC; 193 } else ptmp = X509_PURPOSE_get0(idx); 194 195 /* OPENSSL_free existing name if dynamic */ 196 if(ptmp->flags & X509_PURPOSE_DYNAMIC_NAME) { 197 OPENSSL_free(ptmp->name); 198 OPENSSL_free(ptmp->sname); 199 } 200 /* dup supplied name */ 201 ptmp->name = BUF_strdup(name); 202 ptmp->sname = BUF_strdup(sname); 203 if(!ptmp->name || !ptmp->sname) { 204 OPENSSL_PUT_ERROR(X509V3, X509_PURPOSE_add, ERR_R_MALLOC_FAILURE); 205 return 0; 206 } 207 /* Keep the dynamic flag of existing entry */ 208 ptmp->flags &= X509_PURPOSE_DYNAMIC; 209 /* Set all other flags */ 210 ptmp->flags |= flags; 211 212 ptmp->purpose = id; 213 ptmp->trust = trust; 214 ptmp->check_purpose = ck; 215 ptmp->usr_data = arg; 216 217 /* If its a new entry manage the dynamic table */ 218 if(idx == -1) { 219 if(!xptable && !(xptable = sk_X509_PURPOSE_new(xp_cmp))) { 220 OPENSSL_PUT_ERROR(X509V3, X509_PURPOSE_add, ERR_R_MALLOC_FAILURE); 221 return 0; 222 } 223 if (!sk_X509_PURPOSE_push(xptable, ptmp)) { 224 OPENSSL_PUT_ERROR(X509V3, X509_PURPOSE_add, ERR_R_MALLOC_FAILURE); 225 return 0; 226 } 227 } 228 return 1; 229} 230 231static void xptable_free(X509_PURPOSE *p) 232 { 233 if(!p) return; 234 if (p->flags & X509_PURPOSE_DYNAMIC) 235 { 236 if (p->flags & X509_PURPOSE_DYNAMIC_NAME) { 237 OPENSSL_free(p->name); 238 OPENSSL_free(p->sname); 239 } 240 OPENSSL_free(p); 241 } 242 } 243 244void X509_PURPOSE_cleanup(void) 245{ 246 unsigned int i; 247 sk_X509_PURPOSE_pop_free(xptable, xptable_free); 248 for(i = 0; i < X509_PURPOSE_COUNT; i++) xptable_free(xstandard + i); 249 xptable = NULL; 250} 251 252int X509_PURPOSE_get_id(X509_PURPOSE *xp) 253{ 254 return xp->purpose; 255} 256 257char *X509_PURPOSE_get0_name(X509_PURPOSE *xp) 258{ 259 return xp->name; 260} 261 262char *X509_PURPOSE_get0_sname(X509_PURPOSE *xp) 263{ 264 return xp->sname; 265} 266 267int X509_PURPOSE_get_trust(X509_PURPOSE *xp) 268{ 269 return xp->trust; 270} 271 272static int nid_cmp(const void *void_a, const void *void_b) 273 { 274 const int *a = void_a, *b = void_b; 275 276 return *a - *b; 277 } 278 279int X509_supported_extension(X509_EXTENSION *ex) 280 { 281 /* This table is a list of the NIDs of supported extensions: 282 * that is those which are used by the verify process. If 283 * an extension is critical and doesn't appear in this list 284 * then the verify process will normally reject the certificate. 285 * The list must be kept in numerical order because it will be 286 * searched using bsearch. 287 */ 288 289 static const int supported_nids[] = { 290 NID_netscape_cert_type, /* 71 */ 291 NID_key_usage, /* 83 */ 292 NID_subject_alt_name, /* 85 */ 293 NID_basic_constraints, /* 87 */ 294 NID_certificate_policies, /* 89 */ 295 NID_ext_key_usage, /* 126 */ 296 NID_policy_constraints, /* 401 */ 297 NID_proxyCertInfo, /* 663 */ 298 NID_name_constraints, /* 666 */ 299 NID_policy_mappings, /* 747 */ 300 NID_inhibit_any_policy /* 748 */ 301 }; 302 303 int ex_nid = OBJ_obj2nid(X509_EXTENSION_get_object(ex)); 304 305 if (ex_nid == NID_undef) 306 return 0; 307 308 if (bsearch(&ex_nid, supported_nids, sizeof(supported_nids)/sizeof(int), sizeof(int), nid_cmp) != NULL) 309 return 1; 310 return 0; 311 } 312 313static void setup_dp(X509 *x, DIST_POINT *dp) 314 { 315 X509_NAME *iname = NULL; 316 size_t i; 317 if (dp->reasons) 318 { 319 if (dp->reasons->length > 0) 320 dp->dp_reasons = dp->reasons->data[0]; 321 if (dp->reasons->length > 1) 322 dp->dp_reasons |= (dp->reasons->data[1] << 8); 323 dp->dp_reasons &= CRLDP_ALL_REASONS; 324 } 325 else 326 dp->dp_reasons = CRLDP_ALL_REASONS; 327 if (!dp->distpoint || (dp->distpoint->type != 1)) 328 return; 329 for (i = 0; i < sk_GENERAL_NAME_num(dp->CRLissuer); i++) 330 { 331 GENERAL_NAME *gen = sk_GENERAL_NAME_value(dp->CRLissuer, i); 332 if (gen->type == GEN_DIRNAME) 333 { 334 iname = gen->d.directoryName; 335 break; 336 } 337 } 338 if (!iname) 339 iname = X509_get_issuer_name(x); 340 341 DIST_POINT_set_dpname(dp->distpoint, iname); 342 343 } 344 345static void setup_crldp(X509 *x) 346 { 347 size_t i; 348 x->crldp = X509_get_ext_d2i(x, NID_crl_distribution_points, NULL, NULL); 349 for (i = 0; i < sk_DIST_POINT_num(x->crldp); i++) 350 setup_dp(x, sk_DIST_POINT_value(x->crldp, i)); 351 } 352 353static void x509v3_cache_extensions(X509 *x) 354{ 355 BASIC_CONSTRAINTS *bs; 356 PROXY_CERT_INFO_EXTENSION *pci; 357 ASN1_BIT_STRING *usage; 358 ASN1_BIT_STRING *ns; 359 EXTENDED_KEY_USAGE *extusage; 360 X509_EXTENSION *ex; 361 size_t i; 362 int j; 363 if(x->ex_flags & EXFLAG_SET) return; 364 X509_digest(x, EVP_sha1(), x->sha1_hash, NULL); 365 /* V1 should mean no extensions ... */ 366 if(!X509_get_version(x)) x->ex_flags |= EXFLAG_V1; 367 /* Handle basic constraints */ 368 if((bs=X509_get_ext_d2i(x, NID_basic_constraints, NULL, NULL))) { 369 if(bs->ca) x->ex_flags |= EXFLAG_CA; 370 if(bs->pathlen) { 371 if((bs->pathlen->type == V_ASN1_NEG_INTEGER) 372 || !bs->ca) { 373 x->ex_flags |= EXFLAG_INVALID; 374 x->ex_pathlen = 0; 375 } else x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen); 376 } else x->ex_pathlen = -1; 377 BASIC_CONSTRAINTS_free(bs); 378 x->ex_flags |= EXFLAG_BCONS; 379 } 380 /* Handle proxy certificates */ 381 if((pci=X509_get_ext_d2i(x, NID_proxyCertInfo, NULL, NULL))) { 382 if (x->ex_flags & EXFLAG_CA 383 || X509_get_ext_by_NID(x, NID_subject_alt_name, -1) >= 0 384 || X509_get_ext_by_NID(x, NID_issuer_alt_name, -1) >= 0) { 385 x->ex_flags |= EXFLAG_INVALID; 386 } 387 if (pci->pcPathLengthConstraint) { 388 x->ex_pcpathlen = 389 ASN1_INTEGER_get(pci->pcPathLengthConstraint); 390 } else x->ex_pcpathlen = -1; 391 PROXY_CERT_INFO_EXTENSION_free(pci); 392 x->ex_flags |= EXFLAG_PROXY; 393 } 394 /* Handle key usage */ 395 if((usage=X509_get_ext_d2i(x, NID_key_usage, NULL, NULL))) { 396 if(usage->length > 0) { 397 x->ex_kusage = usage->data[0]; 398 if(usage->length > 1) 399 x->ex_kusage |= usage->data[1] << 8; 400 } else x->ex_kusage = 0; 401 x->ex_flags |= EXFLAG_KUSAGE; 402 ASN1_BIT_STRING_free(usage); 403 } 404 x->ex_xkusage = 0; 405 if((extusage=X509_get_ext_d2i(x, NID_ext_key_usage, NULL, NULL))) { 406 x->ex_flags |= EXFLAG_XKUSAGE; 407 for(i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) { 408 switch(OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage,i))) { 409 case NID_server_auth: 410 x->ex_xkusage |= XKU_SSL_SERVER; 411 break; 412 413 case NID_client_auth: 414 x->ex_xkusage |= XKU_SSL_CLIENT; 415 break; 416 417 case NID_email_protect: 418 x->ex_xkusage |= XKU_SMIME; 419 break; 420 421 case NID_code_sign: 422 x->ex_xkusage |= XKU_CODE_SIGN; 423 break; 424 425 case NID_ms_sgc: 426 case NID_ns_sgc: 427 x->ex_xkusage |= XKU_SGC; 428 break; 429 430 case NID_OCSP_sign: 431 x->ex_xkusage |= XKU_OCSP_SIGN; 432 break; 433 434 case NID_time_stamp: 435 x->ex_xkusage |= XKU_TIMESTAMP; 436 break; 437 438 case NID_dvcs: 439 x->ex_xkusage |= XKU_DVCS; 440 break; 441 442 case NID_anyExtendedKeyUsage: 443 x->ex_xkusage |= XKU_ANYEKU; 444 break; 445 } 446 } 447 sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free); 448 } 449 450 if((ns=X509_get_ext_d2i(x, NID_netscape_cert_type, NULL, NULL))) { 451 if(ns->length > 0) x->ex_nscert = ns->data[0]; 452 else x->ex_nscert = 0; 453 x->ex_flags |= EXFLAG_NSCERT; 454 ASN1_BIT_STRING_free(ns); 455 } 456 x->skid =X509_get_ext_d2i(x, NID_subject_key_identifier, NULL, NULL); 457 x->akid =X509_get_ext_d2i(x, NID_authority_key_identifier, NULL, NULL); 458 /* Does subject name match issuer ? */ 459 if(!X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x))) 460 { 461 x->ex_flags |= EXFLAG_SI; 462 /* If SKID matches AKID also indicate self signed */ 463 if (X509_check_akid(x, x->akid) == X509_V_OK) 464 x->ex_flags |= EXFLAG_SS; 465 } 466 x->altname = X509_get_ext_d2i(x, NID_subject_alt_name, NULL, NULL); 467 x->nc = X509_get_ext_d2i(x, NID_name_constraints, &j, NULL); 468 if (!x->nc && (j != -1)) 469 x->ex_flags |= EXFLAG_INVALID; 470 setup_crldp(x); 471 472 for (j = 0; j < X509_get_ext_count(x); j++) 473 { 474 ex = X509_get_ext(x, j); 475 if (OBJ_obj2nid(X509_EXTENSION_get_object(ex)) 476 == NID_freshest_crl) 477 x->ex_flags |= EXFLAG_FRESHEST; 478 if (!X509_EXTENSION_get_critical(ex)) 479 continue; 480 if (!X509_supported_extension(ex)) 481 { 482 x->ex_flags |= EXFLAG_CRITICAL; 483 break; 484 } 485 } 486 x->ex_flags |= EXFLAG_SET; 487} 488 489/* CA checks common to all purposes 490 * return codes: 491 * 0 not a CA 492 * 1 is a CA 493 * 2 basicConstraints absent so "maybe" a CA 494 * 3 basicConstraints absent but self signed V1. 495 * 4 basicConstraints absent but keyUsage present and keyCertSign asserted. 496 */ 497 498#define V1_ROOT (EXFLAG_V1|EXFLAG_SS) 499#define ku_reject(x, usage) \ 500 (((x)->ex_flags & EXFLAG_KUSAGE) && !((x)->ex_kusage & (usage))) 501#define xku_reject(x, usage) \ 502 (((x)->ex_flags & EXFLAG_XKUSAGE) && !((x)->ex_xkusage & (usage))) 503#define ns_reject(x, usage) \ 504 (((x)->ex_flags & EXFLAG_NSCERT) && !((x)->ex_nscert & (usage))) 505 506static int check_ca(const X509 *x) 507{ 508 /* keyUsage if present should allow cert signing */ 509 if(ku_reject(x, KU_KEY_CERT_SIGN)) return 0; 510 if(x->ex_flags & EXFLAG_BCONS) { 511 if(x->ex_flags & EXFLAG_CA) return 1; 512 /* If basicConstraints says not a CA then say so */ 513 else return 0; 514 } else { 515 /* we support V1 roots for... uh, I don't really know why. */ 516 if((x->ex_flags & V1_ROOT) == V1_ROOT) return 3; 517 /* If key usage present it must have certSign so tolerate it */ 518 else if (x->ex_flags & EXFLAG_KUSAGE) return 4; 519 /* Older certificates could have Netscape-specific CA types */ 520 else if (x->ex_flags & EXFLAG_NSCERT 521 && x->ex_nscert & NS_ANY_CA) return 5; 522 /* can this still be regarded a CA certificate? I doubt it */ 523 return 0; 524 } 525} 526 527int X509_check_ca(X509 *x) 528{ 529 if(!(x->ex_flags & EXFLAG_SET)) { 530 CRYPTO_w_lock(CRYPTO_LOCK_X509); 531 x509v3_cache_extensions(x); 532 CRYPTO_w_unlock(CRYPTO_LOCK_X509); 533 } 534 535 return check_ca(x); 536} 537 538/* Check SSL CA: common checks for SSL client and server */ 539static int check_ssl_ca(const X509 *x) 540{ 541 int ca_ret; 542 ca_ret = check_ca(x); 543 if(!ca_ret) return 0; 544 /* check nsCertType if present */ 545 if(ca_ret != 5 || x->ex_nscert & NS_SSL_CA) return ca_ret; 546 else return 0; 547} 548 549 550static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, int ca) 551{ 552 if(xku_reject(x,XKU_SSL_CLIENT)) return 0; 553 if(ca) return check_ssl_ca(x); 554 /* We need to do digital signatures or key agreement */ 555 if(ku_reject(x,KU_DIGITAL_SIGNATURE|KU_KEY_AGREEMENT)) return 0; 556 /* nsCertType if present should allow SSL client use */ 557 if(ns_reject(x, NS_SSL_CLIENT)) return 0; 558 return 1; 559} 560/* Key usage needed for TLS/SSL server: digital signature, encipherment or 561 * key agreement. The ssl code can check this more thoroughly for individual 562 * key types. 563 */ 564#define KU_TLS \ 565 KU_DIGITAL_SIGNATURE|KU_KEY_ENCIPHERMENT|KU_KEY_AGREEMENT 566 567static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca) 568{ 569 if(xku_reject(x,XKU_SSL_SERVER|XKU_SGC)) return 0; 570 if(ca) return check_ssl_ca(x); 571 572 if(ns_reject(x, NS_SSL_SERVER)) return 0; 573 if(ku_reject(x, KU_TLS)) return 0; 574 575 return 1; 576 577} 578 579static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca) 580{ 581 int ret; 582 ret = check_purpose_ssl_server(xp, x, ca); 583 if(!ret || ca) return ret; 584 /* We need to encipher or Netscape complains */ 585 if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0; 586 return ret; 587} 588 589/* common S/MIME checks */ 590static int purpose_smime(const X509 *x, int ca) 591{ 592 if(xku_reject(x,XKU_SMIME)) return 0; 593 if(ca) { 594 int ca_ret; 595 ca_ret = check_ca(x); 596 if(!ca_ret) return 0; 597 /* check nsCertType if present */ 598 if(ca_ret != 5 || x->ex_nscert & NS_SMIME_CA) return ca_ret; 599 else return 0; 600 } 601 if(x->ex_flags & EXFLAG_NSCERT) { 602 if(x->ex_nscert & NS_SMIME) return 1; 603 /* Workaround for some buggy certificates */ 604 if(x->ex_nscert & NS_SSL_CLIENT) return 2; 605 return 0; 606 } 607 return 1; 608} 609 610static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, int ca) 611{ 612 int ret; 613 ret = purpose_smime(x, ca); 614 if(!ret || ca) return ret; 615 if(ku_reject(x, KU_DIGITAL_SIGNATURE|KU_NON_REPUDIATION)) return 0; 616 return ret; 617} 618 619static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, int ca) 620{ 621 int ret; 622 ret = purpose_smime(x, ca); 623 if(!ret || ca) return ret; 624 if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0; 625 return ret; 626} 627 628static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, int ca) 629{ 630 if(ca) { 631 int ca_ret; 632 if((ca_ret = check_ca(x)) != 2) return ca_ret; 633 else return 0; 634 } 635 if(ku_reject(x, KU_CRL_SIGN)) return 0; 636 return 1; 637} 638 639/* OCSP helper: this is *not* a full OCSP check. It just checks that 640 * each CA is valid. Additional checks must be made on the chain. 641 */ 642 643static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca) 644{ 645 /* Must be a valid CA. Should we really support the "I don't know" 646 value (2)? */ 647 if(ca) return check_ca(x); 648 /* leaf certificate is checked in OCSP_verify() */ 649 return 1; 650} 651 652static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x, 653 int ca) 654{ 655 int i_ext; 656 657 /* If ca is true we must return if this is a valid CA certificate. */ 658 if (ca) return check_ca(x); 659 660 /* 661 * Check the optional key usage field: 662 * if Key Usage is present, it must be one of digitalSignature 663 * and/or nonRepudiation (other values are not consistent and shall 664 * be rejected). 665 */ 666 if ((x->ex_flags & EXFLAG_KUSAGE) 667 && ((x->ex_kusage & ~(KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE)) || 668 !(x->ex_kusage & (KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE)))) 669 return 0; 670 671 /* Only time stamp key usage is permitted and it's required. */ 672 if (!(x->ex_flags & EXFLAG_XKUSAGE) || x->ex_xkusage != XKU_TIMESTAMP) 673 return 0; 674 675 /* Extended Key Usage MUST be critical */ 676 i_ext = X509_get_ext_by_NID((X509 *) x, NID_ext_key_usage, -1); 677 if (i_ext >= 0) 678 { 679 X509_EXTENSION *ext = X509_get_ext((X509 *) x, i_ext); 680 if (!X509_EXTENSION_get_critical(ext)) 681 return 0; 682 } 683 684 return 1; 685} 686 687static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca) 688{ 689 return 1; 690} 691 692/* Various checks to see if one certificate issued the second. 693 * This can be used to prune a set of possible issuer certificates 694 * which have been looked up using some simple method such as by 695 * subject name. 696 * These are: 697 * 1. Check issuer_name(subject) == subject_name(issuer) 698 * 2. If akid(subject) exists check it matches issuer 699 * 3. If key_usage(issuer) exists check it supports certificate signing 700 * returns 0 for OK, positive for reason for mismatch, reasons match 701 * codes for X509_verify_cert() 702 */ 703 704int X509_check_issued(X509 *issuer, X509 *subject) 705{ 706 if(X509_NAME_cmp(X509_get_subject_name(issuer), 707 X509_get_issuer_name(subject))) 708 return X509_V_ERR_SUBJECT_ISSUER_MISMATCH; 709 x509v3_cache_extensions(issuer); 710 x509v3_cache_extensions(subject); 711 712 if(subject->akid) 713 { 714 int ret = X509_check_akid(issuer, subject->akid); 715 if (ret != X509_V_OK) 716 return ret; 717 } 718 719 if(subject->ex_flags & EXFLAG_PROXY) 720 { 721 if(ku_reject(issuer, KU_DIGITAL_SIGNATURE)) 722 return X509_V_ERR_KEYUSAGE_NO_DIGITAL_SIGNATURE; 723 } 724 else if(ku_reject(issuer, KU_KEY_CERT_SIGN)) 725 return X509_V_ERR_KEYUSAGE_NO_CERTSIGN; 726 return X509_V_OK; 727} 728 729int X509_check_akid(X509 *issuer, AUTHORITY_KEYID *akid) 730 { 731 732 if(!akid) 733 return X509_V_OK; 734 735 /* Check key ids (if present) */ 736 if(akid->keyid && issuer->skid && 737 ASN1_OCTET_STRING_cmp(akid->keyid, issuer->skid) ) 738 return X509_V_ERR_AKID_SKID_MISMATCH; 739 /* Check serial number */ 740 if(akid->serial && 741 ASN1_INTEGER_cmp(X509_get_serialNumber(issuer), akid->serial)) 742 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH; 743 /* Check issuer name */ 744 if(akid->issuer) 745 { 746 /* Ugh, for some peculiar reason AKID includes 747 * SEQUENCE OF GeneralName. So look for a DirName. 748 * There may be more than one but we only take any 749 * notice of the first. 750 */ 751 GENERAL_NAMES *gens; 752 GENERAL_NAME *gen; 753 X509_NAME *nm = NULL; 754 size_t i; 755 gens = akid->issuer; 756 for(i = 0; i < sk_GENERAL_NAME_num(gens); i++) 757 { 758 gen = sk_GENERAL_NAME_value(gens, i); 759 if(gen->type == GEN_DIRNAME) 760 { 761 nm = gen->d.dirn; 762 break; 763 } 764 } 765 if(nm && X509_NAME_cmp(nm, X509_get_issuer_name(issuer))) 766 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH; 767 } 768 return X509_V_OK; 769 } 770 771