crypto/libressl/crypto/x509/x509_ncons.c

   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 }