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 <string.h> 60 61#include <openssl/buf.h> 62#include <openssl/err.h> 63#include <openssl/digest.h> 64#include <openssl/mem.h> 65#include <openssl/obj.h> 66#include <openssl/thread.h> 67#include <openssl/x509_vfy.h> 68#include <openssl/x509v3.h> 69 70#include "../internal.h" 71 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 81static void x509v3_cache_extensions(X509 *x); 82 83static int check_ssl_ca(const X509 *x); 84static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, int ca); 85static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca); 86static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca); 87static int purpose_smime(const X509 *x, int ca); 88static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, int ca); 89static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, int ca); 90static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, int ca); 91static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x, int ca); 92static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca); 93static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca); 94 95static int xp_cmp(const X509_PURPOSE **a, const X509_PURPOSE **b); 96static void xptable_free(X509_PURPOSE *p); 97 98static X509_PURPOSE xstandard[] = { 99 {X509_PURPOSE_SSL_CLIENT, X509_TRUST_SSL_CLIENT, 0, check_purpose_ssl_client, (char *) "SSL client", (char *) "sslclient", NULL}, 100 {X509_PURPOSE_SSL_SERVER, X509_TRUST_SSL_SERVER, 0, check_purpose_ssl_server, (char *) "SSL server", (char *) "sslserver", NULL}, 101 {X509_PURPOSE_NS_SSL_SERVER, X509_TRUST_SSL_SERVER, 0, check_purpose_ns_ssl_server, (char *) "Netscape SSL server", (char *) "nssslserver", NULL}, 102 {X509_PURPOSE_SMIME_SIGN, X509_TRUST_EMAIL, 0, check_purpose_smime_sign, (char *) "S/MIME signing", (char *) "smimesign", NULL}, 103 {X509_PURPOSE_SMIME_ENCRYPT, X509_TRUST_EMAIL, 0, check_purpose_smime_encrypt, (char *) "S/MIME encryption", (char *) "smimeencrypt", NULL}, 104 {X509_PURPOSE_CRL_SIGN, X509_TRUST_COMPAT, 0, check_purpose_crl_sign, (char *) "CRL signing", (char *) "crlsign", NULL}, 105 {X509_PURPOSE_ANY, X509_TRUST_DEFAULT, 0, no_check, (char *) "Any Purpose", (char *) "any", NULL}, 106 {X509_PURPOSE_OCSP_HELPER, X509_TRUST_COMPAT, 0, ocsp_helper, (char *) "OCSP helper", (char *) "ocsphelper", NULL}, 107 {X509_PURPOSE_TIMESTAMP_SIGN, X509_TRUST_TSA, 0, check_purpose_timestamp_sign, (char *) "Time Stamp signing", (char *) "timestampsign", NULL}, 108}; 109 110#define X509_PURPOSE_COUNT (sizeof(xstandard)/sizeof(X509_PURPOSE)) 111 112static STACK_OF(X509_PURPOSE) *xptable = NULL; 113 114static int xp_cmp(const X509_PURPOSE **a, const X509_PURPOSE **b) 115{ 116 return (*a)->purpose - (*b)->purpose; 117} 118 119/* As much as I'd like to make X509_check_purpose use a "const" X509* 120 * I really can't because it does recalculate hashes and do other non-const 121 * things. */ 122int X509_check_purpose(X509 *x, int id, int ca) 123{ 124 int idx; 125 const X509_PURPOSE *pt; 126 if(!(x->ex_flags & EXFLAG_SET)) { 127 x509v3_cache_extensions(x); 128 } 129 if(id == -1) return 1; 130 idx = X509_PURPOSE_get_by_id(id); 131 if(idx == -1) return -1; 132 pt = X509_PURPOSE_get0(idx); 133 return pt->check_purpose(pt, x, ca); 134} 135 136int X509_PURPOSE_set(int *p, int purpose) 137{ 138 if(X509_PURPOSE_get_by_id(purpose) == -1) { 139 OPENSSL_PUT_ERROR(X509V3, X509V3_R_INVALID_PURPOSE); 140 return 0; 141 } 142 *p = purpose; 143 return 1; 144} 145 146int X509_PURPOSE_get_count(void) 147{ 148 if(!xptable) return X509_PURPOSE_COUNT; 149 return sk_X509_PURPOSE_num(xptable) + X509_PURPOSE_COUNT; 150} 151 152X509_PURPOSE * X509_PURPOSE_get0(int idx) 153{ 154 if(idx < 0) return NULL; 155 if(idx < (int)X509_PURPOSE_COUNT) return xstandard + idx; 156 return sk_X509_PURPOSE_value(xptable, idx - X509_PURPOSE_COUNT); 157} 158 159int X509_PURPOSE_get_by_sname(char *sname) 160{ 161 int i; 162 X509_PURPOSE *xptmp; 163 for(i = 0; i < X509_PURPOSE_get_count(); i++) { 164 xptmp = X509_PURPOSE_get0(i); 165 if(!strcmp(xptmp->sname, sname)) return i; 166 } 167 return -1; 168} 169 170int X509_PURPOSE_get_by_id(int purpose) 171{ 172 X509_PURPOSE tmp; 173 size_t idx; 174 175 if((purpose >= X509_PURPOSE_MIN) && (purpose <= X509_PURPOSE_MAX)) 176 return purpose - X509_PURPOSE_MIN; 177 tmp.purpose = purpose; 178 if(!xptable) return -1; 179 180 if (!sk_X509_PURPOSE_find(xptable, &idx, &tmp)) 181 return -1; 182 return idx + X509_PURPOSE_COUNT; 183} 184 185int X509_PURPOSE_add(int id, int trust, int flags, 186 int (*ck)(const X509_PURPOSE *, const X509 *, int), 187 char *name, char *sname, void *arg) 188{ 189 int idx; 190 X509_PURPOSE *ptmp; 191 char *name_dup, *sname_dup; 192 193 /* This is set according to what we change: application can't set it */ 194 flags &= ~X509_PURPOSE_DYNAMIC; 195 /* This will always be set for application modified trust entries */ 196 flags |= X509_PURPOSE_DYNAMIC_NAME; 197 /* Get existing entry if any */ 198 idx = X509_PURPOSE_get_by_id(id); 199 /* Need a new entry */ 200 if(idx == -1) { 201 if(!(ptmp = OPENSSL_malloc(sizeof(X509_PURPOSE)))) { 202 OPENSSL_PUT_ERROR(X509V3, ERR_R_MALLOC_FAILURE); 203 return 0; 204 } 205 ptmp->flags = X509_PURPOSE_DYNAMIC; 206 } else ptmp = X509_PURPOSE_get0(idx); 207 208 /* Duplicate the supplied names. */ 209 name_dup = BUF_strdup(name); 210 sname_dup = BUF_strdup(sname); 211 if (name_dup == NULL || sname_dup == NULL) { 212 OPENSSL_PUT_ERROR(X509V3, ERR_R_MALLOC_FAILURE); 213 if (name_dup != NULL) 214 OPENSSL_free(name_dup); 215 if (sname_dup != NULL) 216 OPENSSL_free(sname_dup); 217 if (idx == -1) 218 OPENSSL_free(ptmp); 219 return 0; 220 } 221 222 /* OPENSSL_free existing name if dynamic */ 223 if(ptmp->flags & X509_PURPOSE_DYNAMIC_NAME) { 224 OPENSSL_free(ptmp->name); 225 OPENSSL_free(ptmp->sname); 226 } 227 /* dup supplied name */ 228 ptmp->name = name_dup; 229 ptmp->sname = sname_dup; 230 /* Keep the dynamic flag of existing entry */ 231 ptmp->flags &= X509_PURPOSE_DYNAMIC; 232 /* Set all other flags */ 233 ptmp->flags |= flags; 234 235 ptmp->purpose = id; 236 ptmp->trust = trust; 237 ptmp->check_purpose = ck; 238 ptmp->usr_data = arg; 239 240 /* If its a new entry manage the dynamic table */ 241 if(idx == -1) { 242 if(!xptable && !(xptable = sk_X509_PURPOSE_new(xp_cmp))) { 243 OPENSSL_PUT_ERROR(X509V3, ERR_R_MALLOC_FAILURE); 244 xptable_free(ptmp); 245 return 0; 246 } 247 if (!sk_X509_PURPOSE_push(xptable, ptmp)) { 248 OPENSSL_PUT_ERROR(X509V3, ERR_R_MALLOC_FAILURE); 249 xptable_free(ptmp); 250 return 0; 251 } 252 } 253 return 1; 254} 255 256static void xptable_free(X509_PURPOSE *p) 257 { 258 if(!p) return; 259 if (p->flags & X509_PURPOSE_DYNAMIC) 260 { 261 if (p->flags & X509_PURPOSE_DYNAMIC_NAME) { 262 OPENSSL_free(p->name); 263 OPENSSL_free(p->sname); 264 } 265 OPENSSL_free(p); 266 } 267 } 268 269void X509_PURPOSE_cleanup(void) 270{ 271 unsigned int i; 272 sk_X509_PURPOSE_pop_free(xptable, xptable_free); 273 for(i = 0; i < X509_PURPOSE_COUNT; i++) xptable_free(xstandard + i); 274 xptable = NULL; 275} 276 277int X509_PURPOSE_get_id(X509_PURPOSE *xp) 278{ 279 return xp->purpose; 280} 281 282char *X509_PURPOSE_get0_name(X509_PURPOSE *xp) 283{ 284 return xp->name; 285} 286 287char *X509_PURPOSE_get0_sname(X509_PURPOSE *xp) 288{ 289 return xp->sname; 290} 291 292int X509_PURPOSE_get_trust(X509_PURPOSE *xp) 293{ 294 return xp->trust; 295} 296 297static int nid_cmp(const void *void_a, const void *void_b) 298 { 299 const int *a = void_a, *b = void_b; 300 301 return *a - *b; 302 } 303 304int X509_supported_extension(X509_EXTENSION *ex) 305 { 306 /* This table is a list of the NIDs of supported extensions: 307 * that is those which are used by the verify process. If 308 * an extension is critical and doesn't appear in this list 309 * then the verify process will normally reject the certificate. 310 * The list must be kept in numerical order because it will be 311 * searched using bsearch. 312 */ 313 314 static const int supported_nids[] = { 315 NID_netscape_cert_type, /* 71 */ 316 NID_key_usage, /* 83 */ 317 NID_subject_alt_name, /* 85 */ 318 NID_basic_constraints, /* 87 */ 319 NID_certificate_policies, /* 89 */ 320 NID_ext_key_usage, /* 126 */ 321 NID_policy_constraints, /* 401 */ 322 NID_proxyCertInfo, /* 663 */ 323 NID_name_constraints, /* 666 */ 324 NID_policy_mappings, /* 747 */ 325 NID_inhibit_any_policy /* 748 */ 326 }; 327 328 int ex_nid = OBJ_obj2nid(X509_EXTENSION_get_object(ex)); 329 330 if (ex_nid == NID_undef) 331 return 0; 332 333 if (bsearch(&ex_nid, supported_nids, sizeof(supported_nids)/sizeof(int), sizeof(int), nid_cmp) != NULL) 334 return 1; 335 return 0; 336 } 337 338static void setup_dp(X509 *x, DIST_POINT *dp) 339 { 340 X509_NAME *iname = NULL; 341 size_t i; 342 if (dp->reasons) 343 { 344 if (dp->reasons->length > 0) 345 dp->dp_reasons = dp->reasons->data[0]; 346 if (dp->reasons->length > 1) 347 dp->dp_reasons |= (dp->reasons->data[1] << 8); 348 dp->dp_reasons &= CRLDP_ALL_REASONS; 349 } 350 else 351 dp->dp_reasons = CRLDP_ALL_REASONS; 352 if (!dp->distpoint || (dp->distpoint->type != 1)) 353 return; 354 for (i = 0; i < sk_GENERAL_NAME_num(dp->CRLissuer); i++) 355 { 356 GENERAL_NAME *gen = sk_GENERAL_NAME_value(dp->CRLissuer, i); 357 if (gen->type == GEN_DIRNAME) 358 { 359 iname = gen->d.directoryName; 360 break; 361 } 362 } 363 if (!iname) 364 iname = X509_get_issuer_name(x); 365 366 DIST_POINT_set_dpname(dp->distpoint, iname); 367 368 } 369 370static void setup_crldp(X509 *x) 371 { 372 size_t i; 373 x->crldp = X509_get_ext_d2i(x, NID_crl_distribution_points, NULL, NULL); 374 for (i = 0; i < sk_DIST_POINT_num(x->crldp); i++) 375 setup_dp(x, sk_DIST_POINT_value(x->crldp, i)); 376 } 377 378/* g_x509_cache_extensions_lock is used to protect against concurrent calls to 379 * |x509v3_cache_extensions|. Ideally this would be done with a |CRYPTO_once_t| 380 * in the |X509| structure, but |CRYPTO_once_t| isn't public. 381 * 382 * Note: it's not entirely clear whether this lock is needed. Not all paths to 383 * this function took a lock in OpenSSL. */ 384static struct CRYPTO_STATIC_MUTEX g_x509_cache_extensions_lock = 385 CRYPTO_STATIC_MUTEX_INIT; 386 387static void x509v3_cache_extensions(X509 *x) 388{ 389 BASIC_CONSTRAINTS *bs; 390 PROXY_CERT_INFO_EXTENSION *pci; 391 ASN1_BIT_STRING *usage; 392 ASN1_BIT_STRING *ns; 393 EXTENDED_KEY_USAGE *extusage; 394 X509_EXTENSION *ex; 395 size_t i; 396 int j; 397 398 CRYPTO_STATIC_MUTEX_lock_write(&g_x509_cache_extensions_lock); 399 400 if(x->ex_flags & EXFLAG_SET) 401 { 402 CRYPTO_STATIC_MUTEX_unlock(&g_x509_cache_extensions_lock); 403 return; 404 } 405 406 X509_digest(x, EVP_sha1(), x->sha1_hash, NULL); 407 /* V1 should mean no extensions ... */ 408 if(!X509_get_version(x)) x->ex_flags |= EXFLAG_V1; 409 /* Handle basic constraints */ 410 if((bs=X509_get_ext_d2i(x, NID_basic_constraints, NULL, NULL))) { 411 if(bs->ca) x->ex_flags |= EXFLAG_CA; 412 if(bs->pathlen) { 413 if((bs->pathlen->type == V_ASN1_NEG_INTEGER) 414 || !bs->ca) { 415 x->ex_flags |= EXFLAG_INVALID; 416 x->ex_pathlen = 0; 417 } else x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen); 418 } else x->ex_pathlen = -1; 419 BASIC_CONSTRAINTS_free(bs); 420 x->ex_flags |= EXFLAG_BCONS; 421 } 422 /* Handle proxy certificates */ 423 if((pci=X509_get_ext_d2i(x, NID_proxyCertInfo, NULL, NULL))) { 424 if (x->ex_flags & EXFLAG_CA 425 || X509_get_ext_by_NID(x, NID_subject_alt_name, -1) >= 0 426 || X509_get_ext_by_NID(x, NID_issuer_alt_name, -1) >= 0) { 427 x->ex_flags |= EXFLAG_INVALID; 428 } 429 if (pci->pcPathLengthConstraint) { 430 x->ex_pcpathlen = 431 ASN1_INTEGER_get(pci->pcPathLengthConstraint); 432 } else x->ex_pcpathlen = -1; 433 PROXY_CERT_INFO_EXTENSION_free(pci); 434 x->ex_flags |= EXFLAG_PROXY; 435 } 436 /* Handle key usage */ 437 if((usage=X509_get_ext_d2i(x, NID_key_usage, NULL, NULL))) { 438 if(usage->length > 0) { 439 x->ex_kusage = usage->data[0]; 440 if(usage->length > 1) 441 x->ex_kusage |= usage->data[1] << 8; 442 } else x->ex_kusage = 0; 443 x->ex_flags |= EXFLAG_KUSAGE; 444 ASN1_BIT_STRING_free(usage); 445 } 446 x->ex_xkusage = 0; 447 if((extusage=X509_get_ext_d2i(x, NID_ext_key_usage, NULL, NULL))) { 448 x->ex_flags |= EXFLAG_XKUSAGE; 449 for(i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) { 450 switch(OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage,i))) { 451 case NID_server_auth: 452 x->ex_xkusage |= XKU_SSL_SERVER; 453 break; 454 455 case NID_client_auth: 456 x->ex_xkusage |= XKU_SSL_CLIENT; 457 break; 458 459 case NID_email_protect: 460 x->ex_xkusage |= XKU_SMIME; 461 break; 462 463 case NID_code_sign: 464 x->ex_xkusage |= XKU_CODE_SIGN; 465 break; 466 467 case NID_ms_sgc: 468 case NID_ns_sgc: 469 x->ex_xkusage |= XKU_SGC; 470 break; 471 472 case NID_OCSP_sign: 473 x->ex_xkusage |= XKU_OCSP_SIGN; 474 break; 475 476 case NID_time_stamp: 477 x->ex_xkusage |= XKU_TIMESTAMP; 478 break; 479 480 case NID_dvcs: 481 x->ex_xkusage |= XKU_DVCS; 482 break; 483 484 case NID_anyExtendedKeyUsage: 485 x->ex_xkusage |= XKU_ANYEKU; 486 break; 487 } 488 } 489 sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free); 490 } 491 492 if((ns=X509_get_ext_d2i(x, NID_netscape_cert_type, NULL, NULL))) { 493 if(ns->length > 0) x->ex_nscert = ns->data[0]; 494 else x->ex_nscert = 0; 495 x->ex_flags |= EXFLAG_NSCERT; 496 ASN1_BIT_STRING_free(ns); 497 } 498 x->skid =X509_get_ext_d2i(x, NID_subject_key_identifier, NULL, NULL); 499 x->akid =X509_get_ext_d2i(x, NID_authority_key_identifier, NULL, NULL); 500 /* Does subject name match issuer ? */ 501 if(!X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x))) 502 { 503 x->ex_flags |= EXFLAG_SI; 504 /* If SKID matches AKID also indicate self signed */ 505 if (X509_check_akid(x, x->akid) == X509_V_OK && 506 !ku_reject(x, KU_KEY_CERT_SIGN)) 507 x->ex_flags |= EXFLAG_SS; 508 } 509 x->altname = X509_get_ext_d2i(x, NID_subject_alt_name, NULL, NULL); 510 x->nc = X509_get_ext_d2i(x, NID_name_constraints, &j, NULL); 511 if (!x->nc && (j != -1)) 512 x->ex_flags |= EXFLAG_INVALID; 513 setup_crldp(x); 514 515 for (j = 0; j < X509_get_ext_count(x); j++) 516 { 517 ex = X509_get_ext(x, j); 518 if (OBJ_obj2nid(X509_EXTENSION_get_object(ex)) 519 == NID_freshest_crl) 520 x->ex_flags |= EXFLAG_FRESHEST; 521 if (!X509_EXTENSION_get_critical(ex)) 522 continue; 523 if (!X509_supported_extension(ex)) 524 { 525 x->ex_flags |= EXFLAG_CRITICAL; 526 break; 527 } 528 } 529 x->ex_flags |= EXFLAG_SET; 530 531 CRYPTO_STATIC_MUTEX_unlock(&g_x509_cache_extensions_lock); 532} 533 534/* CA checks common to all purposes 535 * return codes: 536 * 0 not a CA 537 * 1 is a CA 538 * 2 basicConstraints absent so "maybe" a CA 539 * 3 basicConstraints absent but self signed V1. 540 * 4 basicConstraints absent but keyUsage present and keyCertSign asserted. 541 */ 542 543static int check_ca(const X509 *x) 544{ 545 /* keyUsage if present should allow cert signing */ 546 if(ku_reject(x, KU_KEY_CERT_SIGN)) return 0; 547 if(x->ex_flags & EXFLAG_BCONS) { 548 if(x->ex_flags & EXFLAG_CA) return 1; 549 /* If basicConstraints says not a CA then say so */ 550 else return 0; 551 } else { 552 /* we support V1 roots for... uh, I don't really know why. */ 553 if((x->ex_flags & V1_ROOT) == V1_ROOT) return 3; 554 /* If key usage present it must have certSign so tolerate it */ 555 else if (x->ex_flags & EXFLAG_KUSAGE) return 4; 556 /* Older certificates could have Netscape-specific CA types */ 557 else if (x->ex_flags & EXFLAG_NSCERT 558 && x->ex_nscert & NS_ANY_CA) return 5; 559 /* can this still be regarded a CA certificate? I doubt it */ 560 return 0; 561 } 562} 563 564int X509_check_ca(X509 *x) 565{ 566 if(!(x->ex_flags & EXFLAG_SET)) { 567 x509v3_cache_extensions(x); 568 } 569 570 return check_ca(x); 571} 572 573/* Check SSL CA: common checks for SSL client and server */ 574static int check_ssl_ca(const X509 *x) 575{ 576 int ca_ret; 577 ca_ret = check_ca(x); 578 if(!ca_ret) return 0; 579 /* check nsCertType if present */ 580 if(ca_ret != 5 || x->ex_nscert & NS_SSL_CA) return ca_ret; 581 else return 0; 582} 583 584 585static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, int ca) 586{ 587 if(xku_reject(x,XKU_SSL_CLIENT)) return 0; 588 if(ca) return check_ssl_ca(x); 589 /* We need to do digital signatures or key agreement */ 590 if(ku_reject(x,KU_DIGITAL_SIGNATURE|KU_KEY_AGREEMENT)) return 0; 591 /* nsCertType if present should allow SSL client use */ 592 if(ns_reject(x, NS_SSL_CLIENT)) return 0; 593 return 1; 594} 595/* Key usage needed for TLS/SSL server: digital signature, encipherment or 596 * key agreement. The ssl code can check this more thoroughly for individual 597 * key types. 598 */ 599#define KU_TLS \ 600 KU_DIGITAL_SIGNATURE|KU_KEY_ENCIPHERMENT|KU_KEY_AGREEMENT 601 602static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca) 603{ 604 if(xku_reject(x,XKU_SSL_SERVER|XKU_SGC)) return 0; 605 if(ca) return check_ssl_ca(x); 606 607 if(ns_reject(x, NS_SSL_SERVER)) return 0; 608 if(ku_reject(x, KU_TLS)) return 0; 609 610 return 1; 611 612} 613 614static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca) 615{ 616 int ret; 617 ret = check_purpose_ssl_server(xp, x, ca); 618 if(!ret || ca) return ret; 619 /* We need to encipher or Netscape complains */ 620 if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0; 621 return ret; 622} 623 624/* common S/MIME checks */ 625static int purpose_smime(const X509 *x, int ca) 626{ 627 if(xku_reject(x,XKU_SMIME)) return 0; 628 if(ca) { 629 int ca_ret; 630 ca_ret = check_ca(x); 631 if(!ca_ret) return 0; 632 /* check nsCertType if present */ 633 if(ca_ret != 5 || x->ex_nscert & NS_SMIME_CA) return ca_ret; 634 else return 0; 635 } 636 if(x->ex_flags & EXFLAG_NSCERT) { 637 if(x->ex_nscert & NS_SMIME) return 1; 638 /* Workaround for some buggy certificates */ 639 if(x->ex_nscert & NS_SSL_CLIENT) return 2; 640 return 0; 641 } 642 return 1; 643} 644 645static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, int ca) 646{ 647 int ret; 648 ret = purpose_smime(x, ca); 649 if(!ret || ca) return ret; 650 if(ku_reject(x, KU_DIGITAL_SIGNATURE|KU_NON_REPUDIATION)) return 0; 651 return ret; 652} 653 654static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, int ca) 655{ 656 int ret; 657 ret = purpose_smime(x, ca); 658 if(!ret || ca) return ret; 659 if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0; 660 return ret; 661} 662 663static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, int ca) 664{ 665 if(ca) { 666 int ca_ret; 667 if((ca_ret = check_ca(x)) != 2) return ca_ret; 668 else return 0; 669 } 670 if(ku_reject(x, KU_CRL_SIGN)) return 0; 671 return 1; 672} 673 674/* OCSP helper: this is *not* a full OCSP check. It just checks that 675 * each CA is valid. Additional checks must be made on the chain. 676 */ 677 678static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca) 679{ 680 /* Must be a valid CA. Should we really support the "I don't know" 681 value (2)? */ 682 if(ca) return check_ca(x); 683 /* leaf certificate is checked in OCSP_verify() */ 684 return 1; 685} 686 687static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x, 688 int ca) 689{ 690 int i_ext; 691 692 /* If ca is true we must return if this is a valid CA certificate. */ 693 if (ca) return check_ca(x); 694 695 /* 696 * Check the optional key usage field: 697 * if Key Usage is present, it must be one of digitalSignature 698 * and/or nonRepudiation (other values are not consistent and shall 699 * be rejected). 700 */ 701 if ((x->ex_flags & EXFLAG_KUSAGE) 702 && ((x->ex_kusage & ~(KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE)) || 703 !(x->ex_kusage & (KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE)))) 704 return 0; 705 706 /* Only time stamp key usage is permitted and it's required. */ 707 if (!(x->ex_flags & EXFLAG_XKUSAGE) || x->ex_xkusage != XKU_TIMESTAMP) 708 return 0; 709 710 /* Extended Key Usage MUST be critical */ 711 i_ext = X509_get_ext_by_NID((X509 *) x, NID_ext_key_usage, -1); 712 if (i_ext >= 0) 713 { 714 X509_EXTENSION *ext = X509_get_ext((X509 *) x, i_ext); 715 if (!X509_EXTENSION_get_critical(ext)) 716 return 0; 717 } 718 719 return 1; 720} 721 722static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca) 723{ 724 return 1; 725} 726 727/* Various checks to see if one certificate issued the second. 728 * This can be used to prune a set of possible issuer certificates 729 * which have been looked up using some simple method such as by 730 * subject name. 731 * These are: 732 * 1. Check issuer_name(subject) == subject_name(issuer) 733 * 2. If akid(subject) exists check it matches issuer 734 * 3. If key_usage(issuer) exists check it supports certificate signing 735 * returns 0 for OK, positive for reason for mismatch, reasons match 736 * codes for X509_verify_cert() 737 */ 738 739int X509_check_issued(X509 *issuer, X509 *subject) 740{ 741 if(X509_NAME_cmp(X509_get_subject_name(issuer), 742 X509_get_issuer_name(subject))) 743 return X509_V_ERR_SUBJECT_ISSUER_MISMATCH; 744 x509v3_cache_extensions(issuer); 745 x509v3_cache_extensions(subject); 746 747 if(subject->akid) 748 { 749 int ret = X509_check_akid(issuer, subject->akid); 750 if (ret != X509_V_OK) 751 return ret; 752 } 753 754 if(subject->ex_flags & EXFLAG_PROXY) 755 { 756 if(ku_reject(issuer, KU_DIGITAL_SIGNATURE)) 757 return X509_V_ERR_KEYUSAGE_NO_DIGITAL_SIGNATURE; 758 } 759 else if(ku_reject(issuer, KU_KEY_CERT_SIGN)) 760 return X509_V_ERR_KEYUSAGE_NO_CERTSIGN; 761 return X509_V_OK; 762} 763 764int X509_check_akid(X509 *issuer, AUTHORITY_KEYID *akid) 765 { 766 767 if(!akid) 768 return X509_V_OK; 769 770 /* Check key ids (if present) */ 771 if(akid->keyid && issuer->skid && 772 ASN1_OCTET_STRING_cmp(akid->keyid, issuer->skid) ) 773 return X509_V_ERR_AKID_SKID_MISMATCH; 774 /* Check serial number */ 775 if(akid->serial && 776 ASN1_INTEGER_cmp(X509_get_serialNumber(issuer), akid->serial)) 777 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH; 778 /* Check issuer name */ 779 if(akid->issuer) 780 { 781 /* Ugh, for some peculiar reason AKID includes 782 * SEQUENCE OF GeneralName. So look for a DirName. 783 * There may be more than one but we only take any 784 * notice of the first. 785 */ 786 GENERAL_NAMES *gens; 787 GENERAL_NAME *gen; 788 X509_NAME *nm = NULL; 789 size_t i; 790 gens = akid->issuer; 791 for(i = 0; i < sk_GENERAL_NAME_num(gens); i++) 792 { 793 gen = sk_GENERAL_NAME_value(gens, i); 794 if(gen->type == GEN_DIRNAME) 795 { 796 nm = gen->d.dirn; 797 break; 798 } 799 } 800 if(nm && X509_NAME_cmp(nm, X509_get_issuer_name(issuer))) 801 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH; 802 } 803 return X509_V_OK; 804 } 805 806