crypto/libressl/crypto/x509/x509_ncons.c

   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 }