1 /* $OpenBSD: x509_ncons.c,v 1.5 2021/11/01 20:53:08 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_lcl.h" 68 69 static void *v2i_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method, 70 X509V3_CTX *ctx, STACK_OF(CONF_VALUE) *nval); 71 static int i2r_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method, 72 void *a, BIO *bp, int ind); 73 static int do_i2r_name_constraints(const X509V3_EXT_METHOD *method, 74 STACK_OF(GENERAL_SUBTREE) *trees, BIO *bp, int ind, char *name); 75 static int print_nc_ipadd(BIO *bp, ASN1_OCTET_STRING *ip); 76 77 static int nc_match(GENERAL_NAME *gen, NAME_CONSTRAINTS *nc); 78 static int nc_match_single(GENERAL_NAME *sub, GENERAL_NAME *gen); 79 static int nc_dn(X509_NAME *sub, X509_NAME *nm); 80 static int nc_dns(ASN1_IA5STRING *sub, ASN1_IA5STRING *dns); 81 static int nc_email(ASN1_IA5STRING *sub, ASN1_IA5STRING *eml); 82 static int nc_uri(ASN1_IA5STRING *uri, ASN1_IA5STRING *base); 83 84 const 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 }; 100 101 static 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 }; 124 125 const 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 }; 134 135 static 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 }; 151 152 const 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 }; 161 162 163 GENERAL_SUBTREE * 164 GENERAL_SUBTREE_new(void) 165 { 166 return (GENERAL_SUBTREE*)ASN1_item_new(&GENERAL_SUBTREE_it); 167 } 168 169 void 170 GENERAL_SUBTREE_free(GENERAL_SUBTREE *a) 171 { 172 ASN1_item_free((ASN1_VALUE *)a, &GENERAL_SUBTREE_it); 173 } 174 175 NAME_CONSTRAINTS * 176 NAME_CONSTRAINTS_new(void) 177 { 178 return (NAME_CONSTRAINTS*)ASN1_item_new(&NAME_CONSTRAINTS_it); 179 } 180 181 void 182 NAME_CONSTRAINTS_free(NAME_CONSTRAINTS *a) 183 { 184 ASN1_item_free((ASN1_VALUE *)a, &NAME_CONSTRAINTS_it); 185 } 186 187 static void * 188 v2i_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method, X509V3_CTX *ctx, 189 STACK_OF(CONF_VALUE) *nval) 190 { 191 int i; 192 CONF_VALUE tval, *val; 193 STACK_OF(GENERAL_SUBTREE) **ptree = NULL; 194 NAME_CONSTRAINTS *ncons = NULL; 195 GENERAL_SUBTREE *sub = NULL; 196 197 ncons = NAME_CONSTRAINTS_new(); 198 if (!ncons) 199 goto memerr; 200 for (i = 0; i < sk_CONF_VALUE_num(nval); i++) { 201 val = sk_CONF_VALUE_value(nval, i); 202 if (!strncmp(val->name, "permitted", 9) && val->name[9]) { 203 ptree = &ncons->permittedSubtrees; 204 tval.name = val->name + 10; 205 } else if (!strncmp(val->name, "excluded", 8) && val->name[8]) { 206 ptree = &ncons->excludedSubtrees; 207 tval.name = val->name + 9; 208 } else { 209 X509V3error(X509V3_R_INVALID_SYNTAX); 210 goto err; 211 } 212 tval.value = val->value; 213 sub = GENERAL_SUBTREE_new(); 214 if (!v2i_GENERAL_NAME_ex(sub->base, method, ctx, &tval, 1)) 215 goto err; 216 if (!*ptree) 217 *ptree = sk_GENERAL_SUBTREE_new_null(); 218 if (!*ptree || !sk_GENERAL_SUBTREE_push(*ptree, sub)) 219 goto memerr; 220 sub = NULL; 221 } 222 223 return ncons; 224 225 memerr: 226 X509V3error(ERR_R_MALLOC_FAILURE); 227 err: 228 NAME_CONSTRAINTS_free(ncons); 229 GENERAL_SUBTREE_free(sub); 230 return NULL; 231 } 232 233 static int 234 i2r_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method, void *a, BIO *bp, int ind) 235 { 236 NAME_CONSTRAINTS *ncons = a; 237 238 do_i2r_name_constraints(method, ncons->permittedSubtrees, 239 bp, ind, "Permitted"); 240 do_i2r_name_constraints(method, ncons->excludedSubtrees, 241 bp, ind, "Excluded"); 242 return 1; 243 } 244 245 static int 246 do_i2r_name_constraints(const X509V3_EXT_METHOD *method, 247 STACK_OF(GENERAL_SUBTREE) *trees, BIO *bp, int ind, char *name) 248 { 249 GENERAL_SUBTREE *tree; 250 int i; 251 252 if (sk_GENERAL_SUBTREE_num(trees) > 0) 253 BIO_printf(bp, "%*s%s:\n", ind, "", name); 254 for (i = 0; i < sk_GENERAL_SUBTREE_num(trees); i++) { 255 tree = sk_GENERAL_SUBTREE_value(trees, i); 256 BIO_printf(bp, "%*s", ind + 2, ""); 257 if (tree->base->type == GEN_IPADD) 258 print_nc_ipadd(bp, tree->base->d.ip); 259 else 260 GENERAL_NAME_print(bp, tree->base); 261 BIO_puts(bp, "\n"); 262 } 263 return 1; 264 } 265 266 static int 267 print_nc_ipadd(BIO *bp, ASN1_OCTET_STRING *ip) 268 { 269 int i, len; 270 unsigned char *p; 271 272 p = ip->data; 273 len = ip->length; 274 BIO_puts(bp, "IP:"); 275 if (len == 8) { 276 BIO_printf(bp, "%d.%d.%d.%d/%d.%d.%d.%d", 277 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7]); 278 } else if (len == 32) { 279 for (i = 0; i < 16; i++) { 280 BIO_printf(bp, "%X", p[0] << 8 | p[1]); 281 p += 2; 282 if (i == 7) 283 BIO_puts(bp, "/"); 284 else if (i != 15) 285 BIO_puts(bp, ":"); 286 } 287 } else 288 BIO_printf(bp, "IP Address:<invalid>"); 289 return 1; 290 } 291 292 /* Check a certificate conforms to a specified set of constraints. 293 * Return values: 294 * X509_V_OK: All constraints obeyed. 295 * X509_V_ERR_PERMITTED_VIOLATION: Permitted subtree violation. 296 * X509_V_ERR_EXCLUDED_VIOLATION: Excluded subtree violation. 297 * X509_V_ERR_SUBTREE_MINMAX: Min or max values present and matching type. 298 * X509_V_ERR_UNSUPPORTED_CONSTRAINT_TYPE: Unsupported constraint type. 299 * X509_V_ERR_UNSUPPORTED_CONSTRAINT_SYNTAX: bad unsupported constraint syntax. 300 * X509_V_ERR_UNSUPPORTED_NAME_SYNTAX: bad or unsupported syntax of name 301 */ 302 303 int 304 NAME_CONSTRAINTS_check(X509 *x, NAME_CONSTRAINTS *nc) 305 { 306 int r, i; 307 X509_NAME *nm; 308 309 nm = X509_get_subject_name(x); 310 311 if (X509_NAME_entry_count(nm) > 0) { 312 GENERAL_NAME gntmp; 313 gntmp.type = GEN_DIRNAME; 314 gntmp.d.directoryName = nm; 315 316 r = nc_match(&gntmp, nc); 317 318 if (r != X509_V_OK) 319 return r; 320 321 gntmp.type = GEN_EMAIL; 322 323 /* Process any email address attributes in subject name */ 324 325 for (i = -1;;) { 326 X509_NAME_ENTRY *ne; 327 i = X509_NAME_get_index_by_NID(nm, 328 NID_pkcs9_emailAddress, i); 329 if (i == -1) 330 break; 331 ne = X509_NAME_get_entry(nm, i); 332 gntmp.d.rfc822Name = X509_NAME_ENTRY_get_data(ne); 333 if (gntmp.d.rfc822Name->type != V_ASN1_IA5STRING) 334 return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX; 335 336 r = nc_match(&gntmp, nc); 337 338 if (r != X509_V_OK) 339 return r; 340 } 341 342 } 343 344 for (i = 0; i < sk_GENERAL_NAME_num(x->altname); i++) { 345 GENERAL_NAME *gen = sk_GENERAL_NAME_value(x->altname, i); 346 r = nc_match(gen, nc); 347 if (r != X509_V_OK) 348 return r; 349 } 350 return X509_V_OK; 351 } 352 static int 353 nc_match(GENERAL_NAME *gen, NAME_CONSTRAINTS *nc) 354 { 355 GENERAL_SUBTREE *sub; 356 int i, r, match = 0; 357 358 /* Permitted subtrees: if any subtrees exist of matching the type 359 * at least one subtree must match. 360 */ 361 362 for (i = 0; i < sk_GENERAL_SUBTREE_num(nc->permittedSubtrees); i++) { 363 sub = sk_GENERAL_SUBTREE_value(nc->permittedSubtrees, i); 364 if (gen->type != sub->base->type) 365 continue; 366 if (sub->minimum || sub->maximum) 367 return X509_V_ERR_SUBTREE_MINMAX; 368 /* If we already have a match don't bother trying any more */ 369 if (match == 2) 370 continue; 371 if (match == 0) 372 match = 1; 373 r = nc_match_single(gen, sub->base); 374 if (r == X509_V_OK) 375 match = 2; 376 else if (r != X509_V_ERR_PERMITTED_VIOLATION) 377 return r; 378 } 379 380 if (match == 1) 381 return X509_V_ERR_PERMITTED_VIOLATION; 382 383 /* Excluded subtrees: must not match any of these */ 384 385 for (i = 0; i < sk_GENERAL_SUBTREE_num(nc->excludedSubtrees); i++) { 386 sub = sk_GENERAL_SUBTREE_value(nc->excludedSubtrees, i); 387 if (gen->type != sub->base->type) 388 continue; 389 if (sub->minimum || sub->maximum) 390 return X509_V_ERR_SUBTREE_MINMAX; 391 392 r = nc_match_single(gen, sub->base); 393 if (r == X509_V_OK) 394 return X509_V_ERR_EXCLUDED_VIOLATION; 395 else if (r != X509_V_ERR_PERMITTED_VIOLATION) 396 return r; 397 398 } 399 400 return X509_V_OK; 401 } 402 403 static int 404 nc_match_single(GENERAL_NAME *gen, GENERAL_NAME *base) 405 { 406 switch (base->type) { 407 case GEN_DIRNAME: 408 return nc_dn(gen->d.directoryName, base->d.directoryName); 409 410 case GEN_DNS: 411 return nc_dns(gen->d.dNSName, base->d.dNSName); 412 413 case GEN_EMAIL: 414 return nc_email(gen->d.rfc822Name, base->d.rfc822Name); 415 416 case GEN_URI: 417 return nc_uri(gen->d.uniformResourceIdentifier, 418 base->d.uniformResourceIdentifier); 419 420 default: 421 return X509_V_ERR_UNSUPPORTED_CONSTRAINT_TYPE; 422 } 423 } 424 425 /* directoryName name constraint matching. 426 * The canonical encoding of X509_NAME makes this comparison easy. It is 427 * matched if the subtree is a subset of the name. 428 */ 429 430 static int 431 nc_dn(X509_NAME *nm, X509_NAME *base) 432 { 433 /* Ensure canonical encodings are up to date. */ 434 if (nm->modified && i2d_X509_NAME(nm, NULL) < 0) 435 return X509_V_ERR_OUT_OF_MEM; 436 if (base->modified && i2d_X509_NAME(base, NULL) < 0) 437 return X509_V_ERR_OUT_OF_MEM; 438 if (base->canon_enclen > nm->canon_enclen) 439 return X509_V_ERR_PERMITTED_VIOLATION; 440 if (memcmp(base->canon_enc, nm->canon_enc, base->canon_enclen)) 441 return X509_V_ERR_PERMITTED_VIOLATION; 442 return X509_V_OK; 443 } 444 445 static int 446 nc_dns(ASN1_IA5STRING *dns, ASN1_IA5STRING *base) 447 { 448 char *baseptr = (char *)base->data; 449 char *dnsptr = (char *)dns->data; 450 451 /* Empty matches everything */ 452 if (!*baseptr) 453 return X509_V_OK; 454 /* Otherwise can add zero or more components on the left so 455 * compare RHS and if dns is longer and expect '.' as preceding 456 * character. 457 */ 458 if (dns->length > base->length) { 459 dnsptr += dns->length - base->length; 460 if (baseptr[0] != '.' && dnsptr[-1] != '.') 461 return X509_V_ERR_PERMITTED_VIOLATION; 462 } 463 464 if (strcasecmp(baseptr, dnsptr)) 465 return X509_V_ERR_PERMITTED_VIOLATION; 466 467 return X509_V_OK; 468 } 469 470 static int 471 nc_email(ASN1_IA5STRING *eml, ASN1_IA5STRING *base) 472 { 473 const char *baseptr = (char *)base->data; 474 const char *emlptr = (char *)eml->data; 475 const char *baseat = strchr(baseptr, '@'); 476 const char *emlat = strchr(emlptr, '@'); 477 478 if (!emlat) 479 return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX; 480 /* Special case: inital '.' is RHS match */ 481 if (!baseat && (*baseptr == '.')) { 482 if (eml->length > base->length) { 483 emlptr += eml->length - base->length; 484 if (!strcasecmp(baseptr, emlptr)) 485 return X509_V_OK; 486 } 487 return X509_V_ERR_PERMITTED_VIOLATION; 488 } 489 490 /* If we have anything before '@' match local part */ 491 492 if (baseat) { 493 if (baseat != baseptr) { 494 if ((baseat - baseptr) != (emlat - emlptr)) 495 return X509_V_ERR_PERMITTED_VIOLATION; 496 /* Case sensitive match of local part */ 497 if (strncmp(baseptr, emlptr, emlat - emlptr)) 498 return X509_V_ERR_PERMITTED_VIOLATION; 499 } 500 /* Position base after '@' */ 501 baseptr = baseat + 1; 502 } 503 emlptr = emlat + 1; 504 /* Just have hostname left to match: case insensitive */ 505 if (strcasecmp(baseptr, emlptr)) 506 return X509_V_ERR_PERMITTED_VIOLATION; 507 508 return X509_V_OK; 509 } 510 511 static int 512 nc_uri(ASN1_IA5STRING *uri, ASN1_IA5STRING *base) 513 { 514 const char *baseptr = (char *)base->data; 515 const char *hostptr = (char *)uri->data; 516 const char *p = strchr(hostptr, ':'); 517 int hostlen; 518 519 /* Check for foo:// and skip past it */ 520 if (!p || (p[1] != '/') || (p[2] != '/')) 521 return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX; 522 hostptr = p + 3; 523 524 /* Determine length of hostname part of URI */ 525 526 /* Look for a port indicator as end of hostname first */ 527 528 p = strchr(hostptr, ':'); 529 /* Otherwise look for trailing slash */ 530 if (!p) 531 p = strchr(hostptr, '/'); 532 533 if (!p) 534 hostlen = strlen(hostptr); 535 else 536 hostlen = p - hostptr; 537 538 if (hostlen == 0) 539 return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX; 540 541 /* Special case: inital '.' is RHS match */ 542 if (*baseptr == '.') { 543 if (hostlen > base->length) { 544 p = hostptr + hostlen - base->length; 545 if (!strncasecmp(p, baseptr, base->length)) 546 return X509_V_OK; 547 } 548 return X509_V_ERR_PERMITTED_VIOLATION; 549 } 550 551 if ((base->length != (int)hostlen) || 552 strncasecmp(hostptr, baseptr, hostlen)) 553 return X509_V_ERR_PERMITTED_VIOLATION; 554 555 return X509_V_OK; 556 } 557