1/* $OpenBSD: x509_ncons.c,v 1.9 2023/02/16 08:38:17 tb Exp $ */ 2/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL 3 * project. 4 */ 5/* ==================================================================== 6 * Copyright (c) 2003 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/asn1t.h> 63#include <openssl/conf.h> 64#include <openssl/err.h> 65#include <openssl/x509v3.h> 66 67#include "x509_local.h" 68 69static void *v2i_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method, 70 X509V3_CTX *ctx, STACK_OF(CONF_VALUE) *nval); 71static int i2r_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method, 72 void *a, BIO *bp, int ind); 73static int do_i2r_name_constraints(const X509V3_EXT_METHOD *method, 74 STACK_OF(GENERAL_SUBTREE) *trees, BIO *bp, int ind, char *name); 75static int print_nc_ipadd(BIO *bp, ASN1_OCTET_STRING *ip); 76 77static int nc_match(GENERAL_NAME *gen, NAME_CONSTRAINTS *nc); 78static int nc_match_single(GENERAL_NAME *sub, GENERAL_NAME *gen); 79static int nc_dn(X509_NAME *sub, X509_NAME *nm); 80static int nc_dns(ASN1_IA5STRING *sub, ASN1_IA5STRING *dns); 81static int nc_email(ASN1_IA5STRING *sub, ASN1_IA5STRING *eml); 82static int nc_uri(ASN1_IA5STRING *uri, ASN1_IA5STRING *base); 83 84const X509V3_EXT_METHOD v3_name_constraints = { 85 .ext_nid = NID_name_constraints, 86 .ext_flags = 0, 87 .it = &NAME_CONSTRAINTS_it, 88 .ext_new = NULL, 89 .ext_free = NULL, 90 .d2i = NULL, 91 .i2d = NULL, 92 .i2s = NULL, 93 .s2i = NULL, 94 .i2v = NULL, 95 .v2i = v2i_NAME_CONSTRAINTS, 96 .i2r = i2r_NAME_CONSTRAINTS, 97 .r2i = NULL, 98 .usr_data = NULL, 99}; 100 101static const ASN1_TEMPLATE GENERAL_SUBTREE_seq_tt[] = { 102 { 103 .flags = 0, 104 .tag = 0, 105 .offset = offsetof(GENERAL_SUBTREE, base), 106 .field_name = "base", 107 .item = &GENERAL_NAME_it, 108 }, 109 { 110 .flags = ASN1_TFLG_IMPLICIT | ASN1_TFLG_OPTIONAL, 111 .tag = 0, 112 .offset = offsetof(GENERAL_SUBTREE, minimum), 113 .field_name = "minimum", 114 .item = &ASN1_INTEGER_it, 115 }, 116 { 117 .flags = ASN1_TFLG_IMPLICIT | ASN1_TFLG_OPTIONAL, 118 .tag = 1, 119 .offset = offsetof(GENERAL_SUBTREE, maximum), 120 .field_name = "maximum", 121 .item = &ASN1_INTEGER_it, 122 }, 123}; 124 125const ASN1_ITEM GENERAL_SUBTREE_it = { 126 .itype = ASN1_ITYPE_SEQUENCE, 127 .utype = V_ASN1_SEQUENCE, 128 .templates = GENERAL_SUBTREE_seq_tt, 129 .tcount = sizeof(GENERAL_SUBTREE_seq_tt) / sizeof(ASN1_TEMPLATE), 130 .funcs = NULL, 131 .size = sizeof(GENERAL_SUBTREE), 132 .sname = "GENERAL_SUBTREE", 133}; 134 135static const ASN1_TEMPLATE NAME_CONSTRAINTS_seq_tt[] = { 136 { 137 .flags = ASN1_TFLG_IMPLICIT | ASN1_TFLG_SEQUENCE_OF | ASN1_TFLG_OPTIONAL, 138 .tag = 0, 139 .offset = offsetof(NAME_CONSTRAINTS, permittedSubtrees), 140 .field_name = "permittedSubtrees", 141 .item = &GENERAL_SUBTREE_it, 142 }, 143 { 144 .flags = ASN1_TFLG_IMPLICIT | ASN1_TFLG_SEQUENCE_OF | ASN1_TFLG_OPTIONAL, 145 .tag = 1, 146 .offset = offsetof(NAME_CONSTRAINTS, excludedSubtrees), 147 .field_name = "excludedSubtrees", 148 .item = &GENERAL_SUBTREE_it, 149 }, 150}; 151 152const ASN1_ITEM NAME_CONSTRAINTS_it = { 153 .itype = ASN1_ITYPE_SEQUENCE, 154 .utype = V_ASN1_SEQUENCE, 155 .templates = NAME_CONSTRAINTS_seq_tt, 156 .tcount = sizeof(NAME_CONSTRAINTS_seq_tt) / sizeof(ASN1_TEMPLATE), 157 .funcs = NULL, 158 .size = sizeof(NAME_CONSTRAINTS), 159 .sname = "NAME_CONSTRAINTS", 160}; 161 162 163GENERAL_SUBTREE * 164GENERAL_SUBTREE_new(void) 165{ 166 return (GENERAL_SUBTREE*)ASN1_item_new(&GENERAL_SUBTREE_it); 167} 168LCRYPTO_ALIAS(GENERAL_SUBTREE_new); 169 170void 171GENERAL_SUBTREE_free(GENERAL_SUBTREE *a) 172{ 173 ASN1_item_free((ASN1_VALUE *)a, &GENERAL_SUBTREE_it); 174} 175LCRYPTO_ALIAS(GENERAL_SUBTREE_free); 176 177NAME_CONSTRAINTS * 178NAME_CONSTRAINTS_new(void) 179{ 180 return (NAME_CONSTRAINTS*)ASN1_item_new(&NAME_CONSTRAINTS_it); 181} 182LCRYPTO_ALIAS(NAME_CONSTRAINTS_new); 183 184void 185NAME_CONSTRAINTS_free(NAME_CONSTRAINTS *a) 186{ 187 ASN1_item_free((ASN1_VALUE *)a, &NAME_CONSTRAINTS_it); 188} 189LCRYPTO_ALIAS(NAME_CONSTRAINTS_free); 190 191static void * 192v2i_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method, X509V3_CTX *ctx, 193 STACK_OF(CONF_VALUE) *nval) 194{ 195 int i; 196 CONF_VALUE tval, *val; 197 STACK_OF(GENERAL_SUBTREE) **ptree = NULL; 198 NAME_CONSTRAINTS *ncons = NULL; 199 GENERAL_SUBTREE *sub = NULL; 200 201 ncons = NAME_CONSTRAINTS_new(); 202 if (!ncons) 203 goto memerr; 204 for (i = 0; i < sk_CONF_VALUE_num(nval); i++) { 205 val = sk_CONF_VALUE_value(nval, i); 206 if (!strncmp(val->name, "permitted", 9) && val->name[9]) { 207 ptree = &ncons->permittedSubtrees; 208 tval.name = val->name + 10; 209 } else if (!strncmp(val->name, "excluded", 8) && val->name[8]) { 210 ptree = &ncons->excludedSubtrees; 211 tval.name = val->name + 9; 212 } else { 213 X509V3error(X509V3_R_INVALID_SYNTAX); 214 goto err; 215 } 216 tval.value = val->value; 217 sub = GENERAL_SUBTREE_new(); 218 if (!v2i_GENERAL_NAME_ex(sub->base, method, ctx, &tval, 1)) 219 goto err; 220 if (!*ptree) 221 *ptree = sk_GENERAL_SUBTREE_new_null(); 222 if (!*ptree || !sk_GENERAL_SUBTREE_push(*ptree, sub)) 223 goto memerr; 224 sub = NULL; 225 } 226 227 return ncons; 228 229memerr: 230 X509V3error(ERR_R_MALLOC_FAILURE); 231err: 232 NAME_CONSTRAINTS_free(ncons); 233 GENERAL_SUBTREE_free(sub); 234 return NULL; 235} 236 237static int 238i2r_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method, void *a, BIO *bp, int ind) 239{ 240 NAME_CONSTRAINTS *ncons = a; 241 242 do_i2r_name_constraints(method, ncons->permittedSubtrees, 243 bp, ind, "Permitted"); 244 do_i2r_name_constraints(method, ncons->excludedSubtrees, 245 bp, ind, "Excluded"); 246 return 1; 247} 248 249static int 250do_i2r_name_constraints(const X509V3_EXT_METHOD *method, 251 STACK_OF(GENERAL_SUBTREE) *trees, BIO *bp, int ind, char *name) 252{ 253 GENERAL_SUBTREE *tree; 254 int i; 255 256 if (sk_GENERAL_SUBTREE_num(trees) > 0) 257 BIO_printf(bp, "%*s%s:\n", ind, "", name); 258 for (i = 0; i < sk_GENERAL_SUBTREE_num(trees); i++) { 259 tree = sk_GENERAL_SUBTREE_value(trees, i); 260 BIO_printf(bp, "%*s", ind + 2, ""); 261 if (tree->base->type == GEN_IPADD) 262 print_nc_ipadd(bp, tree->base->d.ip); 263 else 264 GENERAL_NAME_print(bp, tree->base); 265 BIO_puts(bp, "\n"); 266 } 267 return 1; 268} 269 270static int 271print_nc_ipadd(BIO *bp, ASN1_OCTET_STRING *ip) 272{ 273 int i, len; 274 unsigned char *p; 275 276 p = ip->data; 277 len = ip->length; 278 BIO_puts(bp, "IP:"); 279 if (len == 8) { 280 BIO_printf(bp, "%d.%d.%d.%d/%d.%d.%d.%d", 281 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7]); 282 } else if (len == 32) { 283 for (i = 0; i < 16; i++) { 284 BIO_printf(bp, "%X", p[0] << 8 | p[1]); 285 p += 2; 286 if (i == 7) 287 BIO_puts(bp, "/"); 288 else if (i != 15) 289 BIO_puts(bp, ":"); 290 } 291 } else 292 BIO_printf(bp, "IP Address:<invalid>"); 293 return 1; 294} 295 296/* Check a certificate conforms to a specified set of constraints. 297 * Return values: 298 * X509_V_OK: All constraints obeyed. 299 * X509_V_ERR_PERMITTED_VIOLATION: Permitted subtree violation. 300 * X509_V_ERR_EXCLUDED_VIOLATION: Excluded subtree violation. 301 * X509_V_ERR_SUBTREE_MINMAX: Min or max values present and matching type. 302 * X509_V_ERR_UNSUPPORTED_CONSTRAINT_TYPE: Unsupported constraint type. 303 * X509_V_ERR_UNSUPPORTED_CONSTRAINT_SYNTAX: bad unsupported constraint syntax. 304 * X509_V_ERR_UNSUPPORTED_NAME_SYNTAX: bad or unsupported syntax of name 305 */ 306 307int 308NAME_CONSTRAINTS_check(X509 *x, NAME_CONSTRAINTS *nc) 309{ 310 int r, i; 311 X509_NAME *nm; 312 313 nm = X509_get_subject_name(x); 314 315 if (X509_NAME_entry_count(nm) > 0) { 316 GENERAL_NAME gntmp; 317 gntmp.type = GEN_DIRNAME; 318 gntmp.d.directoryName = nm; 319 320 r = nc_match(&gntmp, nc); 321 322 if (r != X509_V_OK) 323 return r; 324 325 gntmp.type = GEN_EMAIL; 326 327 /* Process any email address attributes in subject name */ 328 329 for (i = -1;;) { 330 X509_NAME_ENTRY *ne; 331 i = X509_NAME_get_index_by_NID(nm, 332 NID_pkcs9_emailAddress, i); 333 if (i == -1) 334 break; 335 ne = X509_NAME_get_entry(nm, i); 336 gntmp.d.rfc822Name = X509_NAME_ENTRY_get_data(ne); 337 if (gntmp.d.rfc822Name->type != V_ASN1_IA5STRING) 338 return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX; 339 340 r = nc_match(&gntmp, nc); 341 342 if (r != X509_V_OK) 343 return r; 344 } 345 346 } 347 348 for (i = 0; i < sk_GENERAL_NAME_num(x->altname); i++) { 349 GENERAL_NAME *gen = sk_GENERAL_NAME_value(x->altname, i); 350 r = nc_match(gen, nc); 351 if (r != X509_V_OK) 352 return r; 353 } 354 return X509_V_OK; 355} 356LCRYPTO_ALIAS(NAME_CONSTRAINTS_check); 357static int 358nc_match(GENERAL_NAME *gen, NAME_CONSTRAINTS *nc) 359{ 360 GENERAL_SUBTREE *sub; 361 int i, r, match = 0; 362 363 /* Permitted subtrees: if any subtrees exist of matching the type 364 * at least one subtree must match. 365 */ 366 367 for (i = 0; i < sk_GENERAL_SUBTREE_num(nc->permittedSubtrees); i++) { 368 sub = sk_GENERAL_SUBTREE_value(nc->permittedSubtrees, i); 369 if (gen->type != sub->base->type) 370 continue; 371 if (sub->minimum || sub->maximum) 372 return X509_V_ERR_SUBTREE_MINMAX; 373 /* If we already have a match don't bother trying any more */ 374 if (match == 2) 375 continue; 376 if (match == 0) 377 match = 1; 378 r = nc_match_single(gen, sub->base); 379 if (r == X509_V_OK) 380 match = 2; 381 else if (r != X509_V_ERR_PERMITTED_VIOLATION) 382 return r; 383 } 384 385 if (match == 1) 386 return X509_V_ERR_PERMITTED_VIOLATION; 387 388 /* Excluded subtrees: must not match any of these */ 389 390 for (i = 0; i < sk_GENERAL_SUBTREE_num(nc->excludedSubtrees); i++) { 391 sub = sk_GENERAL_SUBTREE_value(nc->excludedSubtrees, i); 392 if (gen->type != sub->base->type) 393 continue; 394 if (sub->minimum || sub->maximum) 395 return X509_V_ERR_SUBTREE_MINMAX; 396 397 r = nc_match_single(gen, sub->base); 398 if (r == X509_V_OK) 399 return X509_V_ERR_EXCLUDED_VIOLATION; 400 else if (r != X509_V_ERR_PERMITTED_VIOLATION) 401 return r; 402 403 } 404 405 return X509_V_OK; 406} 407 408static int 409nc_match_single(GENERAL_NAME *gen, GENERAL_NAME *base) 410{ 411 switch (base->type) { 412 case GEN_DIRNAME: 413 return nc_dn(gen->d.directoryName, base->d.directoryName); 414 415 case GEN_DNS: 416 return nc_dns(gen->d.dNSName, base->d.dNSName); 417 418 case GEN_EMAIL: 419 return nc_email(gen->d.rfc822Name, base->d.rfc822Name); 420 421 case GEN_URI: 422 return nc_uri(gen->d.uniformResourceIdentifier, 423 base->d.uniformResourceIdentifier); 424 425 default: 426 return X509_V_ERR_UNSUPPORTED_CONSTRAINT_TYPE; 427 } 428} 429 430/* directoryName name constraint matching. 431 * The canonical encoding of X509_NAME makes this comparison easy. It is 432 * matched if the subtree is a subset of the name. 433 */ 434 435static int 436nc_dn(X509_NAME *nm, X509_NAME *base) 437{ 438 /* Ensure canonical encodings are up to date. */ 439 if (nm->modified && i2d_X509_NAME(nm, NULL) < 0) 440 return X509_V_ERR_OUT_OF_MEM; 441 if (base->modified && i2d_X509_NAME(base, NULL) < 0) 442 return X509_V_ERR_OUT_OF_MEM; 443 if (base->canon_enclen > nm->canon_enclen) 444 return X509_V_ERR_PERMITTED_VIOLATION; 445 if (memcmp(base->canon_enc, nm->canon_enc, base->canon_enclen)) 446 return X509_V_ERR_PERMITTED_VIOLATION; 447 return X509_V_OK; 448} 449 450static int 451nc_dns(ASN1_IA5STRING *dns, ASN1_IA5STRING *base) 452{ 453 char *baseptr = (char *)base->data; 454 char *dnsptr = (char *)dns->data; 455 456 /* Empty matches everything */ 457 if (!*baseptr) 458 return X509_V_OK; 459 /* Otherwise can add zero or more components on the left so 460 * compare RHS and if dns is longer and expect '.' as preceding 461 * character. 462 */ 463 if (dns->length > base->length) { 464 dnsptr += dns->length - base->length; 465 if (baseptr[0] != '.' && dnsptr[-1] != '.') 466 return X509_V_ERR_PERMITTED_VIOLATION; 467 } 468 469 if (strcasecmp(baseptr, dnsptr)) 470 return X509_V_ERR_PERMITTED_VIOLATION; 471 472 return X509_V_OK; 473} 474 475static int 476nc_email(ASN1_IA5STRING *eml, ASN1_IA5STRING *base) 477{ 478 const char *baseptr = (char *)base->data; 479 const char *emlptr = (char *)eml->data; 480 const char *baseat = strchr(baseptr, '@'); 481 const char *emlat = strchr(emlptr, '@'); 482 483 if (!emlat) 484 return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX; 485 /* Special case: initial '.' is RHS match */ 486 if (!baseat && (*baseptr == '.')) { 487 if (eml->length > base->length) { 488 emlptr += eml->length - base->length; 489 if (!strcasecmp(baseptr, emlptr)) 490 return X509_V_OK; 491 } 492 return X509_V_ERR_PERMITTED_VIOLATION; 493 } 494 495 /* If we have anything before '@' match local part */ 496 497 if (baseat) { 498 if (baseat != baseptr) { 499 if ((baseat - baseptr) != (emlat - emlptr)) 500 return X509_V_ERR_PERMITTED_VIOLATION; 501 /* Case sensitive match of local part */ 502 if (strncmp(baseptr, emlptr, emlat - emlptr)) 503 return X509_V_ERR_PERMITTED_VIOLATION; 504 } 505 /* Position base after '@' */ 506 baseptr = baseat + 1; 507 } 508 emlptr = emlat + 1; 509 /* Just have hostname left to match: case insensitive */ 510 if (strcasecmp(baseptr, emlptr)) 511 return X509_V_ERR_PERMITTED_VIOLATION; 512 513 return X509_V_OK; 514} 515 516static int 517nc_uri(ASN1_IA5STRING *uri, ASN1_IA5STRING *base) 518{ 519 const char *baseptr = (char *)base->data; 520 const char *hostptr = (char *)uri->data; 521 const char *p = strchr(hostptr, ':'); 522 int hostlen; 523 524 /* Check for foo:// and skip past it */ 525 if (!p || (p[1] != '/') || (p[2] != '/')) 526 return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX; 527 hostptr = p + 3; 528 529 /* Determine length of hostname part of URI */ 530 531 /* Look for a port indicator as end of hostname first */ 532 533 p = strchr(hostptr, ':'); 534 /* Otherwise look for trailing slash */ 535 if (!p) 536 p = strchr(hostptr, '/'); 537 538 if (!p) 539 hostlen = strlen(hostptr); 540 else 541 hostlen = p - hostptr; 542 543 if (hostlen == 0) 544 return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX; 545 546 /* Special case: initial '.' is RHS match */ 547 if (*baseptr == '.') { 548 if (hostlen > base->length) { 549 p = hostptr + hostlen - base->length; 550 if (!strncasecmp(p, baseptr, base->length)) 551 return X509_V_OK; 552 } 553 return X509_V_ERR_PERMITTED_VIOLATION; 554 } 555 556 if ((base->length != (int)hostlen) || 557 strncasecmp(hostptr, baseptr, hostlen)) 558 return X509_V_ERR_PERMITTED_VIOLATION; 559 560 return X509_V_OK; 561} 562