v3_purp.c revision 127128
1/* v3_purp.c */ 2/* Written by Dr Stephen N Henson (shenson@bigfoot.com) 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 "cryptlib.h" 61#include <openssl/x509v3.h> 62#include <openssl/x509_vfy.h> 63 64static void x509v3_cache_extensions(X509 *x); 65 66static int ca_check(const X509 *x); 67static int check_ssl_ca(const X509 *x); 68static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, int ca); 69static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca); 70static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca); 71static int purpose_smime(const X509 *x, int ca); 72static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, int ca); 73static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, int ca); 74static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, int ca); 75static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca); 76static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca); 77 78static int xp_cmp(const X509_PURPOSE * const *a, 79 const X509_PURPOSE * const *b); 80static void xptable_free(X509_PURPOSE *p); 81 82static X509_PURPOSE xstandard[] = { 83 {X509_PURPOSE_SSL_CLIENT, X509_TRUST_SSL_CLIENT, 0, check_purpose_ssl_client, "SSL client", "sslclient", NULL}, 84 {X509_PURPOSE_SSL_SERVER, X509_TRUST_SSL_SERVER, 0, check_purpose_ssl_server, "SSL server", "sslserver", NULL}, 85 {X509_PURPOSE_NS_SSL_SERVER, X509_TRUST_SSL_SERVER, 0, check_purpose_ns_ssl_server, "Netscape SSL server", "nssslserver", NULL}, 86 {X509_PURPOSE_SMIME_SIGN, X509_TRUST_EMAIL, 0, check_purpose_smime_sign, "S/MIME signing", "smimesign", NULL}, 87 {X509_PURPOSE_SMIME_ENCRYPT, X509_TRUST_EMAIL, 0, check_purpose_smime_encrypt, "S/MIME encryption", "smimeencrypt", NULL}, 88 {X509_PURPOSE_CRL_SIGN, X509_TRUST_COMPAT, 0, check_purpose_crl_sign, "CRL signing", "crlsign", NULL}, 89 {X509_PURPOSE_ANY, X509_TRUST_DEFAULT, 0, no_check, "Any Purpose", "any", NULL}, 90 {X509_PURPOSE_OCSP_HELPER, X509_TRUST_COMPAT, 0, ocsp_helper, "OCSP helper", "ocsphelper", NULL}, 91}; 92 93#define X509_PURPOSE_COUNT (sizeof(xstandard)/sizeof(X509_PURPOSE)) 94 95IMPLEMENT_STACK_OF(X509_PURPOSE) 96 97static STACK_OF(X509_PURPOSE) *xptable = NULL; 98 99static int xp_cmp(const X509_PURPOSE * const *a, 100 const X509_PURPOSE * const *b) 101{ 102 return (*a)->purpose - (*b)->purpose; 103} 104 105/* As much as I'd like to make X509_check_purpose use a "const" X509* 106 * I really can't because it does recalculate hashes and do other non-const 107 * things. */ 108int X509_check_purpose(X509 *x, int id, int ca) 109{ 110 int idx; 111 const X509_PURPOSE *pt; 112 if(!(x->ex_flags & EXFLAG_SET)) { 113 CRYPTO_w_lock(CRYPTO_LOCK_X509); 114 x509v3_cache_extensions(x); 115 CRYPTO_w_unlock(CRYPTO_LOCK_X509); 116 } 117 if(id == -1) return 1; 118 idx = X509_PURPOSE_get_by_id(id); 119 if(idx == -1) return -1; 120 pt = X509_PURPOSE_get0(idx); 121 return pt->check_purpose(pt, x, ca); 122} 123 124int X509_PURPOSE_set(int *p, int purpose) 125{ 126 if(X509_PURPOSE_get_by_id(purpose) == -1) { 127 X509V3err(X509V3_F_X509_PURPOSE_SET, X509V3_R_INVALID_PURPOSE); 128 return 0; 129 } 130 *p = purpose; 131 return 1; 132} 133 134int X509_PURPOSE_get_count(void) 135{ 136 if(!xptable) return X509_PURPOSE_COUNT; 137 return sk_X509_PURPOSE_num(xptable) + X509_PURPOSE_COUNT; 138} 139 140X509_PURPOSE * X509_PURPOSE_get0(int idx) 141{ 142 if(idx < 0) return NULL; 143 if(idx < X509_PURPOSE_COUNT) return xstandard + idx; 144 return sk_X509_PURPOSE_value(xptable, idx - X509_PURPOSE_COUNT); 145} 146 147int X509_PURPOSE_get_by_sname(char *sname) 148{ 149 int i; 150 X509_PURPOSE *xptmp; 151 for(i = 0; i < X509_PURPOSE_get_count(); i++) { 152 xptmp = X509_PURPOSE_get0(i); 153 if(!strcmp(xptmp->sname, sname)) return i; 154 } 155 return -1; 156} 157 158int X509_PURPOSE_get_by_id(int purpose) 159{ 160 X509_PURPOSE tmp; 161 int idx; 162 if((purpose >= X509_PURPOSE_MIN) && (purpose <= X509_PURPOSE_MAX)) 163 return purpose - X509_PURPOSE_MIN; 164 tmp.purpose = purpose; 165 if(!xptable) return -1; 166 idx = sk_X509_PURPOSE_find(xptable, &tmp); 167 if(idx == -1) return -1; 168 return idx + X509_PURPOSE_COUNT; 169} 170 171int X509_PURPOSE_add(int id, int trust, int flags, 172 int (*ck)(const X509_PURPOSE *, const X509 *, int), 173 char *name, char *sname, void *arg) 174{ 175 int idx; 176 X509_PURPOSE *ptmp; 177 /* This is set according to what we change: application can't set it */ 178 flags &= ~X509_PURPOSE_DYNAMIC; 179 /* This will always be set for application modified trust entries */ 180 flags |= X509_PURPOSE_DYNAMIC_NAME; 181 /* Get existing entry if any */ 182 idx = X509_PURPOSE_get_by_id(id); 183 /* Need a new entry */ 184 if(idx == -1) { 185 if(!(ptmp = OPENSSL_malloc(sizeof(X509_PURPOSE)))) { 186 X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE); 187 return 0; 188 } 189 ptmp->flags = X509_PURPOSE_DYNAMIC; 190 } else ptmp = X509_PURPOSE_get0(idx); 191 192 /* OPENSSL_free existing name if dynamic */ 193 if(ptmp->flags & X509_PURPOSE_DYNAMIC_NAME) { 194 OPENSSL_free(ptmp->name); 195 OPENSSL_free(ptmp->sname); 196 } 197 /* dup supplied name */ 198 ptmp->name = BUF_strdup(name); 199 ptmp->sname = BUF_strdup(sname); 200 if(!ptmp->name || !ptmp->sname) { 201 X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE); 202 return 0; 203 } 204 /* Keep the dynamic flag of existing entry */ 205 ptmp->flags &= X509_PURPOSE_DYNAMIC; 206 /* Set all other flags */ 207 ptmp->flags |= flags; 208 209 ptmp->purpose = id; 210 ptmp->trust = trust; 211 ptmp->check_purpose = ck; 212 ptmp->usr_data = arg; 213 214 /* If its a new entry manage the dynamic table */ 215 if(idx == -1) { 216 if(!xptable && !(xptable = sk_X509_PURPOSE_new(xp_cmp))) { 217 X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE); 218 return 0; 219 } 220 if (!sk_X509_PURPOSE_push(xptable, ptmp)) { 221 X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE); 222 return 0; 223 } 224 } 225 return 1; 226} 227 228static void xptable_free(X509_PURPOSE *p) 229 { 230 if(!p) return; 231 if (p->flags & X509_PURPOSE_DYNAMIC) 232 { 233 if (p->flags & X509_PURPOSE_DYNAMIC_NAME) { 234 OPENSSL_free(p->name); 235 OPENSSL_free(p->sname); 236 } 237 OPENSSL_free(p); 238 } 239 } 240 241void X509_PURPOSE_cleanup(void) 242{ 243 int i; 244 sk_X509_PURPOSE_pop_free(xptable, xptable_free); 245 for(i = 0; i < X509_PURPOSE_COUNT; i++) xptable_free(xstandard + i); 246 xptable = NULL; 247} 248 249int X509_PURPOSE_get_id(X509_PURPOSE *xp) 250{ 251 return xp->purpose; 252} 253 254char *X509_PURPOSE_get0_name(X509_PURPOSE *xp) 255{ 256 return xp->name; 257} 258 259char *X509_PURPOSE_get0_sname(X509_PURPOSE *xp) 260{ 261 return xp->sname; 262} 263 264int X509_PURPOSE_get_trust(X509_PURPOSE *xp) 265{ 266 return xp->trust; 267} 268 269static int nid_cmp(int *a, int *b) 270 { 271 return *a - *b; 272 } 273 274int X509_supported_extension(X509_EXTENSION *ex) 275 { 276 /* This table is a list of the NIDs of supported extensions: 277 * that is those which are used by the verify process. If 278 * an extension is critical and doesn't appear in this list 279 * then the verify process will normally reject the certificate. 280 * The list must be kept in numerical order because it will be 281 * searched using bsearch. 282 */ 283 284 static int supported_nids[] = { 285 NID_netscape_cert_type, /* 71 */ 286 NID_key_usage, /* 83 */ 287 NID_subject_alt_name, /* 85 */ 288 NID_basic_constraints, /* 87 */ 289 NID_ext_key_usage /* 126 */ 290 }; 291 292 int ex_nid; 293 294 ex_nid = OBJ_obj2nid(X509_EXTENSION_get_object(ex)); 295 296 if (ex_nid == NID_undef) 297 return 0; 298 299 if (OBJ_bsearch((char *)&ex_nid, (char *)supported_nids, 300 sizeof(supported_nids)/sizeof(int), sizeof(int), 301 (int (*)(const void *, const void *))nid_cmp)) 302 return 1; 303 return 0; 304 } 305 306 307static void x509v3_cache_extensions(X509 *x) 308{ 309 BASIC_CONSTRAINTS *bs; 310 ASN1_BIT_STRING *usage; 311 ASN1_BIT_STRING *ns; 312 EXTENDED_KEY_USAGE *extusage; 313 X509_EXTENSION *ex; 314 315 int i; 316 if(x->ex_flags & EXFLAG_SET) return; 317#ifndef OPENSSL_NO_SHA 318 X509_digest(x, EVP_sha1(), x->sha1_hash, NULL); 319#endif 320 /* Does subject name match issuer ? */ 321 if(!X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x))) 322 x->ex_flags |= EXFLAG_SS; 323 /* V1 should mean no extensions ... */ 324 if(!X509_get_version(x)) x->ex_flags |= EXFLAG_V1; 325 /* Handle basic constraints */ 326 if((bs=X509_get_ext_d2i(x, NID_basic_constraints, NULL, NULL))) { 327 if(bs->ca) x->ex_flags |= EXFLAG_CA; 328 if(bs->pathlen) { 329 if((bs->pathlen->type == V_ASN1_NEG_INTEGER) 330 || !bs->ca) { 331 x->ex_flags |= EXFLAG_INVALID; 332 x->ex_pathlen = 0; 333 } else x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen); 334 } else x->ex_pathlen = -1; 335 BASIC_CONSTRAINTS_free(bs); 336 x->ex_flags |= EXFLAG_BCONS; 337 } 338 /* Handle key usage */ 339 if((usage=X509_get_ext_d2i(x, NID_key_usage, NULL, NULL))) { 340 if(usage->length > 0) { 341 x->ex_kusage = usage->data[0]; 342 if(usage->length > 1) 343 x->ex_kusage |= usage->data[1] << 8; 344 } else x->ex_kusage = 0; 345 x->ex_flags |= EXFLAG_KUSAGE; 346 ASN1_BIT_STRING_free(usage); 347 } 348 x->ex_xkusage = 0; 349 if((extusage=X509_get_ext_d2i(x, NID_ext_key_usage, NULL, NULL))) { 350 x->ex_flags |= EXFLAG_XKUSAGE; 351 for(i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) { 352 switch(OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage,i))) { 353 case NID_server_auth: 354 x->ex_xkusage |= XKU_SSL_SERVER; 355 break; 356 357 case NID_client_auth: 358 x->ex_xkusage |= XKU_SSL_CLIENT; 359 break; 360 361 case NID_email_protect: 362 x->ex_xkusage |= XKU_SMIME; 363 break; 364 365 case NID_code_sign: 366 x->ex_xkusage |= XKU_CODE_SIGN; 367 break; 368 369 case NID_ms_sgc: 370 case NID_ns_sgc: 371 x->ex_xkusage |= XKU_SGC; 372 break; 373 374 case NID_OCSP_sign: 375 x->ex_xkusage |= XKU_OCSP_SIGN; 376 break; 377 378 case NID_time_stamp: 379 x->ex_xkusage |= XKU_TIMESTAMP; 380 break; 381 382 case NID_dvcs: 383 x->ex_xkusage |= XKU_DVCS; 384 break; 385 } 386 } 387 sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free); 388 } 389 390 if((ns=X509_get_ext_d2i(x, NID_netscape_cert_type, NULL, NULL))) { 391 if(ns->length > 0) x->ex_nscert = ns->data[0]; 392 else x->ex_nscert = 0; 393 x->ex_flags |= EXFLAG_NSCERT; 394 ASN1_BIT_STRING_free(ns); 395 } 396 x->skid =X509_get_ext_d2i(x, NID_subject_key_identifier, NULL, NULL); 397 x->akid =X509_get_ext_d2i(x, NID_authority_key_identifier, NULL, NULL); 398 for (i = 0; i < X509_get_ext_count(x); i++) 399 { 400 ex = X509_get_ext(x, i); 401 if (!X509_EXTENSION_get_critical(ex)) 402 continue; 403 if (!X509_supported_extension(ex)) 404 { 405 x->ex_flags |= EXFLAG_CRITICAL; 406 break; 407 } 408 } 409 x->ex_flags |= EXFLAG_SET; 410} 411 412/* CA checks common to all purposes 413 * return codes: 414 * 0 not a CA 415 * 1 is a CA 416 * 2 basicConstraints absent so "maybe" a CA 417 * 3 basicConstraints absent but self signed V1. 418 * 4 basicConstraints absent but keyUsage present and keyCertSign asserted. 419 */ 420 421#define V1_ROOT (EXFLAG_V1|EXFLAG_SS) 422#define ku_reject(x, usage) \ 423 (((x)->ex_flags & EXFLAG_KUSAGE) && !((x)->ex_kusage & (usage))) 424#define xku_reject(x, usage) \ 425 (((x)->ex_flags & EXFLAG_XKUSAGE) && !((x)->ex_xkusage & (usage))) 426#define ns_reject(x, usage) \ 427 (((x)->ex_flags & EXFLAG_NSCERT) && !((x)->ex_nscert & (usage))) 428 429static int ca_check(const X509 *x) 430{ 431 /* keyUsage if present should allow cert signing */ 432 if(ku_reject(x, KU_KEY_CERT_SIGN)) return 0; 433 if(x->ex_flags & EXFLAG_BCONS) { 434 if(x->ex_flags & EXFLAG_CA) return 1; 435 /* If basicConstraints says not a CA then say so */ 436 else return 0; 437 } else { 438 if((x->ex_flags & V1_ROOT) == V1_ROOT) return 3; 439 /* If key usage present it must have certSign so tolerate it */ 440 else if (x->ex_flags & EXFLAG_KUSAGE) return 4; 441 else return 2; 442 } 443} 444 445/* Check SSL CA: common checks for SSL client and server */ 446static int check_ssl_ca(const X509 *x) 447{ 448 int ca_ret; 449 ca_ret = ca_check(x); 450 if(!ca_ret) return 0; 451 /* check nsCertType if present */ 452 if(x->ex_flags & EXFLAG_NSCERT) { 453 if(x->ex_nscert & NS_SSL_CA) return ca_ret; 454 return 0; 455 } 456 if(ca_ret != 2) return ca_ret; 457 else return 0; 458} 459 460 461static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, int ca) 462{ 463 if(xku_reject(x,XKU_SSL_CLIENT)) return 0; 464 if(ca) return check_ssl_ca(x); 465 /* We need to do digital signatures with it */ 466 if(ku_reject(x,KU_DIGITAL_SIGNATURE)) return 0; 467 /* nsCertType if present should allow SSL client use */ 468 if(ns_reject(x, NS_SSL_CLIENT)) return 0; 469 return 1; 470} 471 472static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca) 473{ 474 if(xku_reject(x,XKU_SSL_SERVER|XKU_SGC)) return 0; 475 if(ca) return check_ssl_ca(x); 476 477 if(ns_reject(x, NS_SSL_SERVER)) return 0; 478 /* Now as for keyUsage: we'll at least need to sign OR encipher */ 479 if(ku_reject(x, KU_DIGITAL_SIGNATURE|KU_KEY_ENCIPHERMENT)) return 0; 480 481 return 1; 482 483} 484 485static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca) 486{ 487 int ret; 488 ret = check_purpose_ssl_server(xp, x, ca); 489 if(!ret || ca) return ret; 490 /* We need to encipher or Netscape complains */ 491 if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0; 492 return ret; 493} 494 495/* common S/MIME checks */ 496static int purpose_smime(const X509 *x, int ca) 497{ 498 if(xku_reject(x,XKU_SMIME)) return 0; 499 if(ca) { 500 int ca_ret; 501 ca_ret = ca_check(x); 502 if(!ca_ret) return 0; 503 /* check nsCertType if present */ 504 if(x->ex_flags & EXFLAG_NSCERT) { 505 if(x->ex_nscert & NS_SMIME_CA) return ca_ret; 506 return 0; 507 } 508 if(ca_ret != 2) return ca_ret; 509 else return 0; 510 } 511 if(x->ex_flags & EXFLAG_NSCERT) { 512 if(x->ex_nscert & NS_SMIME) return 1; 513 /* Workaround for some buggy certificates */ 514 if(x->ex_nscert & NS_SSL_CLIENT) return 2; 515 return 0; 516 } 517 return 1; 518} 519 520static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, int ca) 521{ 522 int ret; 523 ret = purpose_smime(x, ca); 524 if(!ret || ca) return ret; 525 if(ku_reject(x, KU_DIGITAL_SIGNATURE|KU_NON_REPUDIATION)) return 0; 526 return ret; 527} 528 529static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, int ca) 530{ 531 int ret; 532 ret = purpose_smime(x, ca); 533 if(!ret || ca) return ret; 534 if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0; 535 return ret; 536} 537 538static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, int ca) 539{ 540 if(ca) { 541 int ca_ret; 542 if((ca_ret = ca_check(x)) != 2) return ca_ret; 543 else return 0; 544 } 545 if(ku_reject(x, KU_CRL_SIGN)) return 0; 546 return 1; 547} 548 549/* OCSP helper: this is *not* a full OCSP check. It just checks that 550 * each CA is valid. Additional checks must be made on the chain. 551 */ 552 553static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca) 554{ 555 /* Must be a valid CA */ 556 if(ca) { 557 int ca_ret; 558 ca_ret = ca_check(x); 559 if(ca_ret != 2) return ca_ret; 560 if(x->ex_flags & EXFLAG_NSCERT) { 561 if(x->ex_nscert & NS_ANY_CA) return ca_ret; 562 return 0; 563 } 564 return 0; 565 } 566 /* leaf certificate is checked in OCSP_verify() */ 567 return 1; 568} 569 570static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca) 571{ 572 return 1; 573} 574 575/* Various checks to see if one certificate issued the second. 576 * This can be used to prune a set of possible issuer certificates 577 * which have been looked up using some simple method such as by 578 * subject name. 579 * These are: 580 * 1. Check issuer_name(subject) == subject_name(issuer) 581 * 2. If akid(subject) exists check it matches issuer 582 * 3. If key_usage(issuer) exists check it supports certificate signing 583 * returns 0 for OK, positive for reason for mismatch, reasons match 584 * codes for X509_verify_cert() 585 */ 586 587int X509_check_issued(X509 *issuer, X509 *subject) 588{ 589 if(X509_NAME_cmp(X509_get_subject_name(issuer), 590 X509_get_issuer_name(subject))) 591 return X509_V_ERR_SUBJECT_ISSUER_MISMATCH; 592 x509v3_cache_extensions(issuer); 593 x509v3_cache_extensions(subject); 594 if(subject->akid) { 595 /* Check key ids (if present) */ 596 if(subject->akid->keyid && issuer->skid && 597 ASN1_OCTET_STRING_cmp(subject->akid->keyid, issuer->skid) ) 598 return X509_V_ERR_AKID_SKID_MISMATCH; 599 /* Check serial number */ 600 if(subject->akid->serial && 601 ASN1_INTEGER_cmp(X509_get_serialNumber(issuer), 602 subject->akid->serial)) 603 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH; 604 /* Check issuer name */ 605 if(subject->akid->issuer) { 606 /* Ugh, for some peculiar reason AKID includes 607 * SEQUENCE OF GeneralName. So look for a DirName. 608 * There may be more than one but we only take any 609 * notice of the first. 610 */ 611 GENERAL_NAMES *gens; 612 GENERAL_NAME *gen; 613 X509_NAME *nm = NULL; 614 int i; 615 gens = subject->akid->issuer; 616 for(i = 0; i < sk_GENERAL_NAME_num(gens); i++) { 617 gen = sk_GENERAL_NAME_value(gens, i); 618 if(gen->type == GEN_DIRNAME) { 619 nm = gen->d.dirn; 620 break; 621 } 622 } 623 if(nm && X509_NAME_cmp(nm, X509_get_issuer_name(issuer))) 624 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH; 625 } 626 } 627 if(ku_reject(issuer, KU_KEY_CERT_SIGN)) return X509_V_ERR_KEYUSAGE_NO_CERTSIGN; 628 return X509_V_OK; 629} 630 631