1 /* $OpenBSD: x509_ncons.c,v 1.4 2020/09/16 18:12:06 beck 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 static void *v2i_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method, 68 X509V3_CTX *ctx, STACK_OF(CONF_VALUE) *nval); 69 static int i2r_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method, 70 void *a, BIO *bp, int ind); 71 static int do_i2r_name_constraints(const X509V3_EXT_METHOD *method, 72 STACK_OF(GENERAL_SUBTREE) *trees, BIO *bp, int ind, char *name); 73 static int print_nc_ipadd(BIO *bp, ASN1_OCTET_STRING *ip); 74 75 static int nc_match(GENERAL_NAME *gen, NAME_CONSTRAINTS *nc); 76 static int nc_match_single(GENERAL_NAME *sub, GENERAL_NAME *gen); 77 static int nc_dn(X509_NAME *sub, X509_NAME *nm); 78 static int nc_dns(ASN1_IA5STRING *sub, ASN1_IA5STRING *dns); 79 static int nc_email(ASN1_IA5STRING *sub, ASN1_IA5STRING *eml); 80 static int nc_uri(ASN1_IA5STRING *uri, ASN1_IA5STRING *base); 81 82 const X509V3_EXT_METHOD v3_name_constraints = { 83 .ext_nid = NID_name_constraints, 84 .ext_flags = 0, 85 .it = &NAME_CONSTRAINTS_it, 86 .ext_new = NULL, 87 .ext_free = NULL, 88 .d2i = NULL, 89 .i2d = NULL, 90 .i2s = NULL, 91 .s2i = NULL, 92 .i2v = NULL, 93 .v2i = v2i_NAME_CONSTRAINTS, 94 .i2r = i2r_NAME_CONSTRAINTS, 95 .r2i = NULL, 96 .usr_data = NULL, 97 }; 98 99 static const ASN1_TEMPLATE GENERAL_SUBTREE_seq_tt[] = { 100 { 101 .flags = 0, 102 .tag = 0, 103 .offset = offsetof(GENERAL_SUBTREE, base), 104 .field_name = "base", 105 .item = &GENERAL_NAME_it, 106 }, 107 { 108 .flags = ASN1_TFLG_IMPLICIT | ASN1_TFLG_OPTIONAL, 109 .tag = 0, 110 .offset = offsetof(GENERAL_SUBTREE, minimum), 111 .field_name = "minimum", 112 .item = &ASN1_INTEGER_it, 113 }, 114 { 115 .flags = ASN1_TFLG_IMPLICIT | ASN1_TFLG_OPTIONAL, 116 .tag = 1, 117 .offset = offsetof(GENERAL_SUBTREE, maximum), 118 .field_name = "maximum", 119 .item = &ASN1_INTEGER_it, 120 }, 121 }; 122 123 const ASN1_ITEM GENERAL_SUBTREE_it = { 124 .itype = ASN1_ITYPE_SEQUENCE, 125 .utype = V_ASN1_SEQUENCE, 126 .templates = GENERAL_SUBTREE_seq_tt, 127 .tcount = sizeof(GENERAL_SUBTREE_seq_tt) / sizeof(ASN1_TEMPLATE), 128 .funcs = NULL, 129 .size = sizeof(GENERAL_SUBTREE), 130 .sname = "GENERAL_SUBTREE", 131 }; 132 133 static const ASN1_TEMPLATE NAME_CONSTRAINTS_seq_tt[] = { 134 { 135 .flags = ASN1_TFLG_IMPLICIT | ASN1_TFLG_SEQUENCE_OF | ASN1_TFLG_OPTIONAL, 136 .tag = 0, 137 .offset = offsetof(NAME_CONSTRAINTS, permittedSubtrees), 138 .field_name = "permittedSubtrees", 139 .item = &GENERAL_SUBTREE_it, 140 }, 141 { 142 .flags = ASN1_TFLG_IMPLICIT | ASN1_TFLG_SEQUENCE_OF | ASN1_TFLG_OPTIONAL, 143 .tag = 1, 144 .offset = offsetof(NAME_CONSTRAINTS, excludedSubtrees), 145 .field_name = "excludedSubtrees", 146 .item = &GENERAL_SUBTREE_it, 147 }, 148 }; 149 150 const ASN1_ITEM NAME_CONSTRAINTS_it = { 151 .itype = ASN1_ITYPE_SEQUENCE, 152 .utype = V_ASN1_SEQUENCE, 153 .templates = NAME_CONSTRAINTS_seq_tt, 154 .tcount = sizeof(NAME_CONSTRAINTS_seq_tt) / sizeof(ASN1_TEMPLATE), 155 .funcs = NULL, 156 .size = sizeof(NAME_CONSTRAINTS), 157 .sname = "NAME_CONSTRAINTS", 158 }; 159 160 161 GENERAL_SUBTREE * 162 GENERAL_SUBTREE_new(void) 163 { 164 return (GENERAL_SUBTREE*)ASN1_item_new(&GENERAL_SUBTREE_it); 165 } 166 167 void 168 GENERAL_SUBTREE_free(GENERAL_SUBTREE *a) 169 { 170 ASN1_item_free((ASN1_VALUE *)a, &GENERAL_SUBTREE_it); 171 } 172 173 NAME_CONSTRAINTS * 174 NAME_CONSTRAINTS_new(void) 175 { 176 return (NAME_CONSTRAINTS*)ASN1_item_new(&NAME_CONSTRAINTS_it); 177 } 178 179 void 180 NAME_CONSTRAINTS_free(NAME_CONSTRAINTS *a) 181 { 182 ASN1_item_free((ASN1_VALUE *)a, &NAME_CONSTRAINTS_it); 183 } 184 185 static void * 186 v2i_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method, X509V3_CTX *ctx, 187 STACK_OF(CONF_VALUE) *nval) 188 { 189 int i; 190 CONF_VALUE tval, *val; 191 STACK_OF(GENERAL_SUBTREE) **ptree = NULL; 192 NAME_CONSTRAINTS *ncons = NULL; 193 GENERAL_SUBTREE *sub = NULL; 194 195 ncons = NAME_CONSTRAINTS_new(); 196 if (!ncons) 197 goto memerr; 198 for (i = 0; i < sk_CONF_VALUE_num(nval); i++) { 199 val = sk_CONF_VALUE_value(nval, i); 200 if (!strncmp(val->name, "permitted", 9) && val->name[9]) { 201 ptree = &ncons->permittedSubtrees; 202 tval.name = val->name + 10; 203 } else if (!strncmp(val->name, "excluded", 8) && val->name[8]) { 204 ptree = &ncons->excludedSubtrees; 205 tval.name = val->name + 9; 206 } else { 207 X509V3error(X509V3_R_INVALID_SYNTAX); 208 goto err; 209 } 210 tval.value = val->value; 211 sub = GENERAL_SUBTREE_new(); 212 if (!v2i_GENERAL_NAME_ex(sub->base, method, ctx, &tval, 1)) 213 goto err; 214 if (!*ptree) 215 *ptree = sk_GENERAL_SUBTREE_new_null(); 216 if (!*ptree || !sk_GENERAL_SUBTREE_push(*ptree, sub)) 217 goto memerr; 218 sub = NULL; 219 } 220 221 return ncons; 222 223 memerr: 224 X509V3error(ERR_R_MALLOC_FAILURE); 225 err: 226 NAME_CONSTRAINTS_free(ncons); 227 GENERAL_SUBTREE_free(sub); 228 return NULL; 229 } 230 231 static int 232 i2r_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method, void *a, BIO *bp, int ind) 233 { 234 NAME_CONSTRAINTS *ncons = a; 235 236 do_i2r_name_constraints(method, ncons->permittedSubtrees, 237 bp, ind, "Permitted"); 238 do_i2r_name_constraints(method, ncons->excludedSubtrees, 239 bp, ind, "Excluded"); 240 return 1; 241 } 242 243 static int 244 do_i2r_name_constraints(const X509V3_EXT_METHOD *method, 245 STACK_OF(GENERAL_SUBTREE) *trees, BIO *bp, int ind, char *name) 246 { 247 GENERAL_SUBTREE *tree; 248 int i; 249 250 if (sk_GENERAL_SUBTREE_num(trees) > 0) 251 BIO_printf(bp, "%*s%s:\n", ind, "", name); 252 for (i = 0; i < sk_GENERAL_SUBTREE_num(trees); i++) { 253 tree = sk_GENERAL_SUBTREE_value(trees, i); 254 BIO_printf(bp, "%*s", ind + 2, ""); 255 if (tree->base->type == GEN_IPADD) 256 print_nc_ipadd(bp, tree->base->d.ip); 257 else 258 GENERAL_NAME_print(bp, tree->base); 259 BIO_puts(bp, "\n"); 260 } 261 return 1; 262 } 263 264 static int 265 print_nc_ipadd(BIO *bp, ASN1_OCTET_STRING *ip) 266 { 267 int i, len; 268 unsigned char *p; 269 270 p = ip->data; 271 len = ip->length; 272 BIO_puts(bp, "IP:"); 273 if (len == 8) { 274 BIO_printf(bp, "%d.%d.%d.%d/%d.%d.%d.%d", 275 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7]); 276 } else if (len == 32) { 277 for (i = 0; i < 16; i++) { 278 BIO_printf(bp, "%X", p[0] << 8 | p[1]); 279 p += 2; 280 if (i == 7) 281 BIO_puts(bp, "/"); 282 else if (i != 15) 283 BIO_puts(bp, ":"); 284 } 285 } else 286 BIO_printf(bp, "IP Address:<invalid>"); 287 return 1; 288 } 289 290 /* Check a certificate conforms to a specified set of constraints. 291 * Return values: 292 * X509_V_OK: All constraints obeyed. 293 * X509_V_ERR_PERMITTED_VIOLATION: Permitted subtree violation. 294 * X509_V_ERR_EXCLUDED_VIOLATION: Excluded subtree violation. 295 * X509_V_ERR_SUBTREE_MINMAX: Min or max values present and matching type. 296 * X509_V_ERR_UNSUPPORTED_CONSTRAINT_TYPE: Unsupported constraint type. 297 * X509_V_ERR_UNSUPPORTED_CONSTRAINT_SYNTAX: bad unsupported constraint syntax. 298 * X509_V_ERR_UNSUPPORTED_NAME_SYNTAX: bad or unsupported syntax of name 299 */ 300 301 int 302 NAME_CONSTRAINTS_check(X509 *x, NAME_CONSTRAINTS *nc) 303 { 304 int r, i; 305 X509_NAME *nm; 306 307 nm = X509_get_subject_name(x); 308 309 if (X509_NAME_entry_count(nm) > 0) { 310 GENERAL_NAME gntmp; 311 gntmp.type = GEN_DIRNAME; 312 gntmp.d.directoryName = nm; 313 314 r = nc_match(&gntmp, nc); 315 316 if (r != X509_V_OK) 317 return r; 318 319 gntmp.type = GEN_EMAIL; 320 321 /* Process any email address attributes in subject name */ 322 323 for (i = -1;;) { 324 X509_NAME_ENTRY *ne; 325 i = X509_NAME_get_index_by_NID(nm, 326 NID_pkcs9_emailAddress, i); 327 if (i == -1) 328 break; 329 ne = X509_NAME_get_entry(nm, i); 330 gntmp.d.rfc822Name = X509_NAME_ENTRY_get_data(ne); 331 if (gntmp.d.rfc822Name->type != V_ASN1_IA5STRING) 332 return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX; 333 334 r = nc_match(&gntmp, nc); 335 336 if (r != X509_V_OK) 337 return r; 338 } 339 340 } 341 342 for (i = 0; i < sk_GENERAL_NAME_num(x->altname); i++) { 343 GENERAL_NAME *gen = sk_GENERAL_NAME_value(x->altname, i); 344 r = nc_match(gen, nc); 345 if (r != X509_V_OK) 346 return r; 347 } 348 return X509_V_OK; 349 } 350 static int 351 nc_match(GENERAL_NAME *gen, NAME_CONSTRAINTS *nc) 352 { 353 GENERAL_SUBTREE *sub; 354 int i, r, match = 0; 355 356 /* Permitted subtrees: if any subtrees exist of matching the type 357 * at least one subtree must match. 358 */ 359 360 for (i = 0; i < sk_GENERAL_SUBTREE_num(nc->permittedSubtrees); i++) { 361 sub = sk_GENERAL_SUBTREE_value(nc->permittedSubtrees, i); 362 if (gen->type != sub->base->type) 363 continue; 364 if (sub->minimum || sub->maximum) 365 return X509_V_ERR_SUBTREE_MINMAX; 366 /* If we already have a match don't bother trying any more */ 367 if (match == 2) 368 continue; 369 if (match == 0) 370 match = 1; 371 r = nc_match_single(gen, sub->base); 372 if (r == X509_V_OK) 373 match = 2; 374 else if (r != X509_V_ERR_PERMITTED_VIOLATION) 375 return r; 376 } 377 378 if (match == 1) 379 return X509_V_ERR_PERMITTED_VIOLATION; 380 381 /* Excluded subtrees: must not match any of these */ 382 383 for (i = 0; i < sk_GENERAL_SUBTREE_num(nc->excludedSubtrees); i++) { 384 sub = sk_GENERAL_SUBTREE_value(nc->excludedSubtrees, i); 385 if (gen->type != sub->base->type) 386 continue; 387 if (sub->minimum || sub->maximum) 388 return X509_V_ERR_SUBTREE_MINMAX; 389 390 r = nc_match_single(gen, sub->base); 391 if (r == X509_V_OK) 392 return X509_V_ERR_EXCLUDED_VIOLATION; 393 else if (r != X509_V_ERR_PERMITTED_VIOLATION) 394 return r; 395 396 } 397 398 return X509_V_OK; 399 } 400 401 static int 402 nc_match_single(GENERAL_NAME *gen, GENERAL_NAME *base) 403 { 404 switch (base->type) { 405 case GEN_DIRNAME: 406 return nc_dn(gen->d.directoryName, base->d.directoryName); 407 408 case GEN_DNS: 409 return nc_dns(gen->d.dNSName, base->d.dNSName); 410 411 case GEN_EMAIL: 412 return nc_email(gen->d.rfc822Name, base->d.rfc822Name); 413 414 case GEN_URI: 415 return nc_uri(gen->d.uniformResourceIdentifier, 416 base->d.uniformResourceIdentifier); 417 418 default: 419 return X509_V_ERR_UNSUPPORTED_CONSTRAINT_TYPE; 420 } 421 } 422 423 /* directoryName name constraint matching. 424 * The canonical encoding of X509_NAME makes this comparison easy. It is 425 * matched if the subtree is a subset of the name. 426 */ 427 428 static int 429 nc_dn(X509_NAME *nm, X509_NAME *base) 430 { 431 /* Ensure canonical encodings are up to date. */ 432 if (nm->modified && i2d_X509_NAME(nm, NULL) < 0) 433 return X509_V_ERR_OUT_OF_MEM; 434 if (base->modified && i2d_X509_NAME(base, NULL) < 0) 435 return X509_V_ERR_OUT_OF_MEM; 436 if (base->canon_enclen > nm->canon_enclen) 437 return X509_V_ERR_PERMITTED_VIOLATION; 438 if (memcmp(base->canon_enc, nm->canon_enc, base->canon_enclen)) 439 return X509_V_ERR_PERMITTED_VIOLATION; 440 return X509_V_OK; 441 } 442 443 static int 444 nc_dns(ASN1_IA5STRING *dns, ASN1_IA5STRING *base) 445 { 446 char *baseptr = (char *)base->data; 447 char *dnsptr = (char *)dns->data; 448 449 /* Empty matches everything */ 450 if (!*baseptr) 451 return X509_V_OK; 452 /* Otherwise can add zero or more components on the left so 453 * compare RHS and if dns is longer and expect '.' as preceding 454 * character. 455 */ 456 if (dns->length > base->length) { 457 dnsptr += dns->length - base->length; 458 if (baseptr[0] != '.' && dnsptr[-1] != '.') 459 return X509_V_ERR_PERMITTED_VIOLATION; 460 } 461 462 if (strcasecmp(baseptr, dnsptr)) 463 return X509_V_ERR_PERMITTED_VIOLATION; 464 465 return X509_V_OK; 466 } 467 468 static int 469 nc_email(ASN1_IA5STRING *eml, ASN1_IA5STRING *base) 470 { 471 const char *baseptr = (char *)base->data; 472 const char *emlptr = (char *)eml->data; 473 const char *baseat = strchr(baseptr, '@'); 474 const char *emlat = strchr(emlptr, '@'); 475 476 if (!emlat) 477 return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX; 478 /* Special case: inital '.' is RHS match */ 479 if (!baseat && (*baseptr == '.')) { 480 if (eml->length > base->length) { 481 emlptr += eml->length - base->length; 482 if (!strcasecmp(baseptr, emlptr)) 483 return X509_V_OK; 484 } 485 return X509_V_ERR_PERMITTED_VIOLATION; 486 } 487 488 /* If we have anything before '@' match local part */ 489 490 if (baseat) { 491 if (baseat != baseptr) { 492 if ((baseat - baseptr) != (emlat - emlptr)) 493 return X509_V_ERR_PERMITTED_VIOLATION; 494 /* Case sensitive match of local part */ 495 if (strncmp(baseptr, emlptr, emlat - emlptr)) 496 return X509_V_ERR_PERMITTED_VIOLATION; 497 } 498 /* Position base after '@' */ 499 baseptr = baseat + 1; 500 } 501 emlptr = emlat + 1; 502 /* Just have hostname left to match: case insensitive */ 503 if (strcasecmp(baseptr, emlptr)) 504 return X509_V_ERR_PERMITTED_VIOLATION; 505 506 return X509_V_OK; 507 } 508 509 static int 510 nc_uri(ASN1_IA5STRING *uri, ASN1_IA5STRING *base) 511 { 512 const char *baseptr = (char *)base->data; 513 const char *hostptr = (char *)uri->data; 514 const char *p = strchr(hostptr, ':'); 515 int hostlen; 516 517 /* Check for foo:// and skip past it */ 518 if (!p || (p[1] != '/') || (p[2] != '/')) 519 return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX; 520 hostptr = p + 3; 521 522 /* Determine length of hostname part of URI */ 523 524 /* Look for a port indicator as end of hostname first */ 525 526 p = strchr(hostptr, ':'); 527 /* Otherwise look for trailing slash */ 528 if (!p) 529 p = strchr(hostptr, '/'); 530 531 if (!p) 532 hostlen = strlen(hostptr); 533 else 534 hostlen = p - hostptr; 535 536 if (hostlen == 0) 537 return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX; 538 539 /* Special case: inital '.' is RHS match */ 540 if (*baseptr == '.') { 541 if (hostlen > base->length) { 542 p = hostptr + hostlen - base->length; 543 if (!strncasecmp(p, baseptr, base->length)) 544 return X509_V_OK; 545 } 546 return X509_V_ERR_PERMITTED_VIOLATION; 547 } 548 549 if ((base->length != (int)hostlen) || 550 strncasecmp(hostptr, baseptr, hostlen)) 551 return X509_V_ERR_PERMITTED_VIOLATION; 552 553 return X509_V_OK; 554 } 555