v3_purp.c revision 72613
1/* v3_purp.c */ 2/* Written by Dr Stephen N Henson (shenson@bigfoot.com) for the OpenSSL 3 * project 1999. 4 */ 5/* ==================================================================== 6 * Copyright (c) 1999 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 64 65static void x509v3_cache_extensions(X509 *x); 66 67static int ca_check(const X509 *x); 68static int check_ssl_ca(const X509 *x); 69static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, int ca); 70static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca); 71static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca); 72static int purpose_smime(const X509 *x, int ca); 73static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, int ca); 74static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, int ca); 75static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, int ca); 76static int no_check(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}; 91 92#define X509_PURPOSE_COUNT (sizeof(xstandard)/sizeof(X509_PURPOSE)) 93 94IMPLEMENT_STACK_OF(X509_PURPOSE) 95 96static STACK_OF(X509_PURPOSE) *xptable = NULL; 97 98static int xp_cmp(const X509_PURPOSE * const *a, 99 const X509_PURPOSE * const *b) 100{ 101 return (*a)->purpose - (*b)->purpose; 102} 103 104/* As much as I'd like to make X509_check_purpose use a "const" X509* 105 * I really can't because it does recalculate hashes and do other non-const 106 * things. */ 107int X509_check_purpose(X509 *x, int id, int ca) 108{ 109 int idx; 110 const X509_PURPOSE *pt; 111 if(!(x->ex_flags & EXFLAG_SET)) { 112 CRYPTO_w_lock(CRYPTO_LOCK_X509); 113 x509v3_cache_extensions(x); 114 CRYPTO_w_unlock(CRYPTO_LOCK_X509); 115 } 116 if(id == -1) return 1; 117 idx = X509_PURPOSE_get_by_id(id); 118 if(idx == -1) return -1; 119 pt = X509_PURPOSE_get0(idx); 120 return pt->check_purpose(pt, x, ca); 121} 122 123int X509_PURPOSE_get_count(void) 124{ 125 if(!xptable) return X509_PURPOSE_COUNT; 126 return sk_X509_PURPOSE_num(xptable) + X509_PURPOSE_COUNT; 127} 128 129X509_PURPOSE * X509_PURPOSE_get0(int idx) 130{ 131 if(idx < 0) return NULL; 132 if(idx < X509_PURPOSE_COUNT) return xstandard + idx; 133 return sk_X509_PURPOSE_value(xptable, idx - X509_PURPOSE_COUNT); 134} 135 136int X509_PURPOSE_get_by_sname(char *sname) 137{ 138 int i; 139 X509_PURPOSE *xptmp; 140 for(i = 0; i < X509_PURPOSE_get_count(); i++) { 141 xptmp = X509_PURPOSE_get0(i); 142 if(!strcmp(xptmp->sname, sname)) return i; 143 } 144 return -1; 145} 146 147 148int X509_PURPOSE_get_by_id(int purpose) 149{ 150 X509_PURPOSE tmp; 151 int idx; 152 if((purpose >= X509_PURPOSE_MIN) && (purpose <= X509_PURPOSE_MAX)) 153 return purpose - X509_PURPOSE_MIN; 154 tmp.purpose = purpose; 155 if(!xptable) return -1; 156 idx = sk_X509_PURPOSE_find(xptable, &tmp); 157 if(idx == -1) return -1; 158 return idx + X509_PURPOSE_COUNT; 159} 160 161int X509_PURPOSE_add(int id, int trust, int flags, 162 int (*ck)(const X509_PURPOSE *, const X509 *, int), 163 char *name, char *sname, void *arg) 164{ 165 int idx; 166 X509_PURPOSE *ptmp; 167 /* This is set according to what we change: application can't set it */ 168 flags &= ~X509_PURPOSE_DYNAMIC; 169 /* This will always be set for application modified trust entries */ 170 flags |= X509_PURPOSE_DYNAMIC_NAME; 171 /* Get existing entry if any */ 172 idx = X509_PURPOSE_get_by_id(id); 173 /* Need a new entry */ 174 if(idx == -1) { 175 if(!(ptmp = OPENSSL_malloc(sizeof(X509_PURPOSE)))) { 176 X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE); 177 return 0; 178 } 179 ptmp->flags = X509_PURPOSE_DYNAMIC; 180 } else ptmp = X509_PURPOSE_get0(idx); 181 182 /* OPENSSL_free existing name if dynamic */ 183 if(ptmp->flags & X509_PURPOSE_DYNAMIC_NAME) { 184 OPENSSL_free(ptmp->name); 185 OPENSSL_free(ptmp->sname); 186 } 187 /* dup supplied name */ 188 ptmp->name = BUF_strdup(name); 189 ptmp->sname = BUF_strdup(sname); 190 if(!ptmp->name || !ptmp->sname) { 191 X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE); 192 return 0; 193 } 194 /* Keep the dynamic flag of existing entry */ 195 ptmp->flags &= X509_PURPOSE_DYNAMIC; 196 /* Set all other flags */ 197 ptmp->flags |= flags; 198 199 ptmp->purpose = id; 200 ptmp->trust = trust; 201 ptmp->check_purpose = ck; 202 ptmp->usr_data = arg; 203 204 /* If its a new entry manage the dynamic table */ 205 if(idx == -1) { 206 if(!xptable && !(xptable = sk_X509_PURPOSE_new(xp_cmp))) { 207 X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE); 208 return 0; 209 } 210 if (!sk_X509_PURPOSE_push(xptable, ptmp)) { 211 X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE); 212 return 0; 213 } 214 } 215 return 1; 216} 217 218static void xptable_free(X509_PURPOSE *p) 219 { 220 if(!p) return; 221 if (p->flags & X509_PURPOSE_DYNAMIC) 222 { 223 if (p->flags & X509_PURPOSE_DYNAMIC_NAME) { 224 OPENSSL_free(p->name); 225 OPENSSL_free(p->sname); 226 } 227 OPENSSL_free(p); 228 } 229 } 230 231void X509_PURPOSE_cleanup(void) 232{ 233 int i; 234 sk_X509_PURPOSE_pop_free(xptable, xptable_free); 235 for(i = 0; i < X509_PURPOSE_COUNT; i++) xptable_free(xstandard + i); 236 xptable = NULL; 237} 238 239int X509_PURPOSE_get_id(X509_PURPOSE *xp) 240{ 241 return xp->purpose; 242} 243 244char *X509_PURPOSE_get0_name(X509_PURPOSE *xp) 245{ 246 return xp->name; 247} 248 249char *X509_PURPOSE_get0_sname(X509_PURPOSE *xp) 250{ 251 return xp->sname; 252} 253 254int X509_PURPOSE_get_trust(X509_PURPOSE *xp) 255{ 256 return xp->trust; 257} 258 259static void x509v3_cache_extensions(X509 *x) 260{ 261 BASIC_CONSTRAINTS *bs; 262 ASN1_BIT_STRING *usage; 263 ASN1_BIT_STRING *ns; 264 STACK_OF(ASN1_OBJECT) *extusage; 265 266 int i; 267 if(x->ex_flags & EXFLAG_SET) return; 268#ifndef NO_SHA 269 X509_digest(x, EVP_sha1(), x->sha1_hash, NULL); 270#endif 271 /* Does subject name match issuer ? */ 272 if(!X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x))) 273 x->ex_flags |= EXFLAG_SS; 274 /* V1 should mean no extensions ... */ 275 if(!X509_get_version(x)) x->ex_flags |= EXFLAG_V1; 276 /* Handle basic constraints */ 277 if((bs=X509_get_ext_d2i(x, NID_basic_constraints, NULL, NULL))) { 278 if(bs->ca) x->ex_flags |= EXFLAG_CA; 279 if(bs->pathlen) { 280 if((bs->pathlen->type == V_ASN1_NEG_INTEGER) 281 || !bs->ca) { 282 x->ex_flags |= EXFLAG_INVALID; 283 x->ex_pathlen = 0; 284 } else x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen); 285 } else x->ex_pathlen = -1; 286 BASIC_CONSTRAINTS_free(bs); 287 x->ex_flags |= EXFLAG_BCONS; 288 } 289 /* Handle key usage */ 290 if((usage=X509_get_ext_d2i(x, NID_key_usage, NULL, NULL))) { 291 if(usage->length > 0) { 292 x->ex_kusage = usage->data[0]; 293 if(usage->length > 1) 294 x->ex_kusage |= usage->data[1] << 8; 295 } else x->ex_kusage = 0; 296 x->ex_flags |= EXFLAG_KUSAGE; 297 ASN1_BIT_STRING_free(usage); 298 } 299 x->ex_xkusage = 0; 300 if((extusage=X509_get_ext_d2i(x, NID_ext_key_usage, NULL, NULL))) { 301 x->ex_flags |= EXFLAG_XKUSAGE; 302 for(i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) { 303 switch(OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage,i))) { 304 case NID_server_auth: 305 x->ex_xkusage |= XKU_SSL_SERVER; 306 break; 307 308 case NID_client_auth: 309 x->ex_xkusage |= XKU_SSL_CLIENT; 310 break; 311 312 case NID_email_protect: 313 x->ex_xkusage |= XKU_SMIME; 314 break; 315 316 case NID_code_sign: 317 x->ex_xkusage |= XKU_CODE_SIGN; 318 break; 319 320 case NID_ms_sgc: 321 case NID_ns_sgc: 322 x->ex_xkusage |= XKU_SGC; 323 } 324 } 325 sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free); 326 } 327 328 if((ns=X509_get_ext_d2i(x, NID_netscape_cert_type, NULL, NULL))) { 329 if(ns->length > 0) x->ex_nscert = ns->data[0]; 330 else x->ex_nscert = 0; 331 x->ex_flags |= EXFLAG_NSCERT; 332 ASN1_BIT_STRING_free(ns); 333 } 334 x->skid =X509_get_ext_d2i(x, NID_subject_key_identifier, NULL, NULL); 335 x->akid =X509_get_ext_d2i(x, NID_authority_key_identifier, NULL, NULL); 336 x->ex_flags |= EXFLAG_SET; 337} 338 339/* CA checks common to all purposes 340 * return codes: 341 * 0 not a CA 342 * 1 is a CA 343 * 2 basicConstraints absent so "maybe" a CA 344 * 3 basicConstraints absent but self signed V1. 345 */ 346 347#define V1_ROOT (EXFLAG_V1|EXFLAG_SS) 348#define ku_reject(x, usage) \ 349 (((x)->ex_flags & EXFLAG_KUSAGE) && !((x)->ex_kusage & (usage))) 350#define xku_reject(x, usage) \ 351 (((x)->ex_flags & EXFLAG_XKUSAGE) && !((x)->ex_xkusage & (usage))) 352#define ns_reject(x, usage) \ 353 (((x)->ex_flags & EXFLAG_NSCERT) && !((x)->ex_nscert & (usage))) 354 355static int ca_check(const X509 *x) 356{ 357 /* keyUsage if present should allow cert signing */ 358 if(ku_reject(x, KU_KEY_CERT_SIGN)) return 0; 359 if(x->ex_flags & EXFLAG_BCONS) { 360 if(x->ex_flags & EXFLAG_CA) return 1; 361 /* If basicConstraints says not a CA then say so */ 362 else return 0; 363 } else { 364 if((x->ex_flags & V1_ROOT) == V1_ROOT) return 3; 365 /* If key usage present it must have certSign so tolerate it */ 366 else if (x->ex_flags & EXFLAG_KUSAGE) return 3; 367 else return 2; 368 } 369} 370 371/* Check SSL CA: common checks for SSL client and server */ 372static int check_ssl_ca(const X509 *x) 373{ 374 int ca_ret; 375 ca_ret = ca_check(x); 376 if(!ca_ret) return 0; 377 /* check nsCertType if present */ 378 if(x->ex_flags & EXFLAG_NSCERT) { 379 if(x->ex_nscert & NS_SSL_CA) return ca_ret; 380 return 0; 381 } 382 if(ca_ret != 2) return ca_ret; 383 else return 0; 384} 385 386 387static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, int ca) 388{ 389 if(xku_reject(x,XKU_SSL_CLIENT)) return 0; 390 if(ca) return check_ssl_ca(x); 391 /* We need to do digital signatures with it */ 392 if(ku_reject(x,KU_DIGITAL_SIGNATURE)) return 0; 393 /* nsCertType if present should allow SSL client use */ 394 if(ns_reject(x, NS_SSL_CLIENT)) return 0; 395 return 1; 396} 397 398static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca) 399{ 400 if(xku_reject(x,XKU_SSL_SERVER|XKU_SGC)) return 0; 401 if(ca) return check_ssl_ca(x); 402 403 if(ns_reject(x, NS_SSL_SERVER)) return 0; 404 /* Now as for keyUsage: we'll at least need to sign OR encipher */ 405 if(ku_reject(x, KU_DIGITAL_SIGNATURE|KU_KEY_ENCIPHERMENT)) return 0; 406 407 return 1; 408 409} 410 411static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca) 412{ 413 int ret; 414 ret = check_purpose_ssl_server(xp, x, ca); 415 if(!ret || ca) return ret; 416 /* We need to encipher or Netscape complains */ 417 if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0; 418 return ret; 419} 420 421/* common S/MIME checks */ 422static int purpose_smime(const X509 *x, int ca) 423{ 424 if(xku_reject(x,XKU_SMIME)) return 0; 425 if(ca) { 426 int ca_ret; 427 ca_ret = ca_check(x); 428 if(!ca_ret) return 0; 429 /* check nsCertType if present */ 430 if(x->ex_flags & EXFLAG_NSCERT) { 431 if(x->ex_nscert & NS_SMIME_CA) return ca_ret; 432 return 0; 433 } 434 if(ca_ret != 2) return ca_ret; 435 else return 0; 436 } 437 if(x->ex_flags & EXFLAG_NSCERT) { 438 if(x->ex_nscert & NS_SMIME) return 1; 439 /* Workaround for some buggy certificates */ 440 if(x->ex_nscert & NS_SSL_CLIENT) return 2; 441 return 0; 442 } 443 return 1; 444} 445 446static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, int ca) 447{ 448 int ret; 449 ret = purpose_smime(x, ca); 450 if(!ret || ca) return ret; 451 if(ku_reject(x, KU_DIGITAL_SIGNATURE|KU_NON_REPUDIATION)) return 0; 452 return ret; 453} 454 455static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, int ca) 456{ 457 int ret; 458 ret = purpose_smime(x, ca); 459 if(!ret || ca) return ret; 460 if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0; 461 return ret; 462} 463 464static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, int ca) 465{ 466 if(ca) { 467 int ca_ret; 468 if((ca_ret = ca_check(x)) != 2) return ca_ret; 469 else return 0; 470 } 471 if(ku_reject(x, KU_CRL_SIGN)) return 0; 472 return 1; 473} 474 475static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca) 476{ 477 return 1; 478} 479 480/* Various checks to see if one certificate issued the second. 481 * This can be used to prune a set of possible issuer certificates 482 * which have been looked up using some simple method such as by 483 * subject name. 484 * These are: 485 * 1. Check issuer_name(subject) == subject_name(issuer) 486 * 2. If akid(subject) exists check it matches issuer 487 * 3. If key_usage(issuer) exists check it supports certificate signing 488 * returns 0 for OK, positive for reason for mismatch, reasons match 489 * codes for X509_verify_cert() 490 */ 491 492int X509_check_issued(X509 *issuer, X509 *subject) 493{ 494 if(X509_NAME_cmp(X509_get_subject_name(issuer), 495 X509_get_issuer_name(subject))) 496 return X509_V_ERR_SUBJECT_ISSUER_MISMATCH; 497 x509v3_cache_extensions(issuer); 498 x509v3_cache_extensions(subject); 499 if(subject->akid) { 500 /* Check key ids (if present) */ 501 if(subject->akid->keyid && issuer->skid && 502 ASN1_OCTET_STRING_cmp(subject->akid->keyid, issuer->skid) ) 503 return X509_V_ERR_AKID_SKID_MISMATCH; 504 /* Check serial number */ 505 if(subject->akid->serial && 506 ASN1_INTEGER_cmp(X509_get_serialNumber(issuer), 507 subject->akid->serial)) 508 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH; 509 /* Check issuer name */ 510 if(subject->akid->issuer) { 511 /* Ugh, for some peculiar reason AKID includes 512 * SEQUENCE OF GeneralName. So look for a DirName. 513 * There may be more than one but we only take any 514 * notice of the first. 515 */ 516 STACK_OF(GENERAL_NAME) *gens; 517 GENERAL_NAME *gen; 518 X509_NAME *nm = NULL; 519 int i; 520 gens = subject->akid->issuer; 521 for(i = 0; i < sk_GENERAL_NAME_num(gens); i++) { 522 gen = sk_GENERAL_NAME_value(gens, i); 523 if(gen->type == GEN_DIRNAME) { 524 nm = gen->d.dirn; 525 break; 526 } 527 } 528 if(nm && X509_NAME_cmp(nm, X509_get_issuer_name(issuer))) 529 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH; 530 } 531 } 532 if(ku_reject(issuer, KU_KEY_CERT_SIGN)) return X509_V_ERR_KEYUSAGE_NO_CERTSIGN; 533 return X509_V_OK; 534} 535 536