crypto/x509/v3_ncons.c

   1 /*
   2  * Copyright 2003-2021 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 #include "internal/cryptlib.h"
  11 #include "internal/numbers.h"
  12 #include <stdio.h>
  13 #include "crypto/asn1.h"
  14 #include <openssl/asn1t.h>
  15 #include <openssl/conf.h>
  16 #include <openssl/x509v3.h>
  17 #include <openssl/bn.h>
  18
  19 #include "crypto/x509.h"
  20 #include "crypto/punycode.h"
  21 #include "ext_dat.h"
  22
  23 static void *v2i_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method,
  24                                   X509V3_CTX *ctx,
  25                                   STACK_OF(CONF_VALUE) *nval);
  26 static int i2r_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method, void *a,
  27                                 BIO *bp, int ind);
  28 static int do_i2r_name_constraints(const X509V3_EXT_METHOD *method,
  29                                    STACK_OF(GENERAL_SUBTREE) *trees, BIO *bp,
  30                                    int ind, const char *name);
  31 static int print_nc_ipadd(BIO *bp, ASN1_OCTET_STRING *ip);
  32
  33 static int nc_match(GENERAL_NAME *gen, NAME_CONSTRAINTS *nc);
  34 static int nc_match_single(GENERAL_NAME *sub, GENERAL_NAME *gen);
  35 static int nc_dn(const X509_NAME *sub, const X509_NAME *nm);
  36 static int nc_dns(ASN1_IA5STRING *sub, ASN1_IA5STRING *dns);
  37 static int nc_email(ASN1_IA5STRING *sub, ASN1_IA5STRING *eml);
  38 static int nc_email_eai(ASN1_UTF8STRING *sub, ASN1_IA5STRING *eml);
  39 static int nc_uri(ASN1_IA5STRING *uri, ASN1_IA5STRING *base);
  40 static int nc_ip(ASN1_OCTET_STRING *ip, ASN1_OCTET_STRING *base);
  41
  42 const X509V3_EXT_METHOD ossl_v3_name_constraints = {
  43     NID_name_constraints, 0,
  44     ASN1_ITEM_ref(NAME_CONSTRAINTS),
  45     0, 0, 0, 0,
  46     0, 0,
  47     0, v2i_NAME_CONSTRAINTS,
  48     i2r_NAME_CONSTRAINTS, 0,
  49     NULL
  50 };
  51
  52 ASN1_SEQUENCE(GENERAL_SUBTREE) = {
  53         ASN1_SIMPLE(GENERAL_SUBTREE, base, GENERAL_NAME),
  54         ASN1_IMP_OPT(GENERAL_SUBTREE, minimum, ASN1_INTEGER, 0),
  55         ASN1_IMP_OPT(GENERAL_SUBTREE, maximum, ASN1_INTEGER, 1)
  56 } ASN1_SEQUENCE_END(GENERAL_SUBTREE)
  57
  58 ASN1_SEQUENCE(NAME_CONSTRAINTS) = {
  59         ASN1_IMP_SEQUENCE_OF_OPT(NAME_CONSTRAINTS, permittedSubtrees,
  60                                                         GENERAL_SUBTREE, 0),
  61         ASN1_IMP_SEQUENCE_OF_OPT(NAME_CONSTRAINTS, excludedSubtrees,
  62                                                         GENERAL_SUBTREE, 1),
  63 } ASN1_SEQUENCE_END(NAME_CONSTRAINTS)
  64
  65
  66 IMPLEMENT_ASN1_ALLOC_FUNCTIONS(GENERAL_SUBTREE)
  67 IMPLEMENT_ASN1_ALLOC_FUNCTIONS(NAME_CONSTRAINTS)
  68
  69 /*
  70  * We cannot use strncasecmp here because that applies locale specific rules.
  71  * For example in Turkish 'I' is not the uppercase character for 'i'. We need to
  72  * do a simple ASCII case comparison ignoring the locale (that is why we use
  73  * numeric constants below).
  74  */
  75 static int ia5ncasecmp(const char *s1, const char *s2, size_t n)
  76 {
  77     for (; n > 0; n--, s1++, s2++) {
  78         if (*s1 != *s2) {
  79             unsigned char c1 = (unsigned char)*s1, c2 = (unsigned char)*s2;
  80
  81             /* Convert to lower case */
  82             if (c1 >= 0x41 /* A */ && c1 <= 0x5A /* Z */)
  83                 c1 += 0x20;
  84             if (c2 >= 0x41 /* A */ && c2 <= 0x5A /* Z */)
  85                 c2 += 0x20;
  86
  87             if (c1 == c2)
  88                 continue;
  89
  90             if (c1 < c2)
  91                 return -1;
  92
  93             /* c1 > c2 */
  94             return 1;
  95         } else if (*s1 == 0) {
  96             /* If we get here we know that *s2 == 0 too */
  97             return 0;
  98         }
  99     }
 100
 101     return 0;
 102 }
 103
 104 static int ia5casecmp(const char *s1, const char *s2)
 105 {
 106     return ia5ncasecmp(s1, s2, SIZE_MAX);
 107 }
 108
 109 static void *v2i_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method,
 110                                   X509V3_CTX *ctx, STACK_OF(CONF_VALUE) *nval)
 111 {
 112     int i;
 113     CONF_VALUE tval, *val;
 114     STACK_OF(GENERAL_SUBTREE) **ptree = NULL;
 115     NAME_CONSTRAINTS *ncons = NULL;
 116     GENERAL_SUBTREE *sub = NULL;
 117
 118     ncons = NAME_CONSTRAINTS_new();
 119     if (ncons == NULL)
 120         goto memerr;
 121     for (i = 0; i < sk_CONF_VALUE_num(nval); i++) {
 122         val = sk_CONF_VALUE_value(nval, i);
 123         if (strncmp(val->name, "permitted", 9) == 0 && val->name[9]) {
 124             ptree = &ncons->permittedSubtrees;
 125             tval.name = val->name + 10;
 126         } else if (strncmp(val->name, "excluded", 8) == 0 && val->name[8]) {
 127             ptree = &ncons->excludedSubtrees;
 128             tval.name = val->name + 9;
 129         } else {
 130             ERR_raise(ERR_LIB_X509V3, X509V3_R_INVALID_SYNTAX);
 131             goto err;
 132         }
 133         tval.value = val->value;
 134         sub = GENERAL_SUBTREE_new();
 135         if (sub == NULL)
 136             goto memerr;
 137         if (!v2i_GENERAL_NAME_ex(sub->base, method, ctx, &tval, 1))
 138             goto err;
 139         if (*ptree == NULL)
 140             *ptree = sk_GENERAL_SUBTREE_new_null();
 141         if (*ptree == NULL || !sk_GENERAL_SUBTREE_push(*ptree, sub))
 142             goto memerr;
 143         sub = NULL;
 144     }
 145
 146     return ncons;
 147
 148  memerr:
 149     ERR_raise(ERR_LIB_X509V3, ERR_R_MALLOC_FAILURE);
 150  err:
 151     NAME_CONSTRAINTS_free(ncons);
 152     GENERAL_SUBTREE_free(sub);
 153
 154     return NULL;
 155 }
 156
 157 static int i2r_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method, void *a,
 158                                 BIO *bp, int ind)
 159 {
 160     NAME_CONSTRAINTS *ncons = a;
 161     do_i2r_name_constraints(method, ncons->permittedSubtrees,
 162                             bp, ind, "Permitted");
 163     if (ncons->permittedSubtrees && ncons->excludedSubtrees)
 164         BIO_puts(bp, "\n");
 165     do_i2r_name_constraints(method, ncons->excludedSubtrees,
 166                             bp, ind, "Excluded");
 167     return 1;
 168 }
 169
 170 static int do_i2r_name_constraints(const X509V3_EXT_METHOD *method,
 171                                    STACK_OF(GENERAL_SUBTREE) *trees,
 172                                    BIO *bp, int ind, const char *name)
 173 {
 174     GENERAL_SUBTREE *tree;
 175     int i;
 176     if (sk_GENERAL_SUBTREE_num(trees) > 0)
 177         BIO_printf(bp, "%*s%s:\n", ind, "", name);
 178     for (i = 0; i < sk_GENERAL_SUBTREE_num(trees); i++) {
 179         if (i > 0)
 180             BIO_puts(bp, "\n");
 181         tree = sk_GENERAL_SUBTREE_value(trees, i);
 182         BIO_printf(bp, "%*s", ind + 2, "");
 183         if (tree->base->type == GEN_IPADD)
 184             print_nc_ipadd(bp, tree->base->d.ip);
 185         else
 186             GENERAL_NAME_print(bp, tree->base);
 187     }
 188     return 1;
 189 }
 190
 191 static int print_nc_ipadd(BIO *bp, ASN1_OCTET_STRING *ip)
 192 {
 193     /* ip->length should be 8 or 32 and len1 == len2 == 4 or len1 == len2 == 16 */
 194     int len1 = ip->length >= 16 ? 16 : ip->length >= 4 ? 4 : ip->length;
 195     int len2 = ip->length - len1;
 196     char *ip1 = ossl_ipaddr_to_asc(ip->data, len1);
 197     char *ip2 = ossl_ipaddr_to_asc(ip->data + len1, len2);
 198     int ret = ip1 != NULL && ip2 != NULL
 199         && BIO_printf(bp, "IP:%s/%s", ip1, ip2) > 0;
 200
 201     OPENSSL_free(ip1);
 202     OPENSSL_free(ip2);
 203     return ret;
 204 }
 205
 206 #define NAME_CHECK_MAX (1 << 20)
 207
 208 static int add_lengths(int *out, int a, int b)
 209 {
 210     /* sk_FOO_num(NULL) returns -1 but is effectively 0 when iterating. */
 211     if (a < 0)
 212         a = 0;
 213     if (b < 0)
 214         b = 0;
 215
 216     if (a > INT_MAX - b)
 217         return 0;
 218     *out = a + b;
 219     return 1;
 220 }
 221
 222 /*-
 223  * Check a certificate conforms to a specified set of constraints.
 224  * Return values:
 225  *  X509_V_OK: All constraints obeyed.
 226  *  X509_V_ERR_PERMITTED_VIOLATION: Permitted subtree violation.
 227  *  X509_V_ERR_EXCLUDED_VIOLATION: Excluded subtree violation.
 228  *  X509_V_ERR_SUBTREE_MINMAX: Min or max values present and matching type.
 229  *  X509_V_ERR_UNSUPPORTED_CONSTRAINT_TYPE:  Unsupported constraint type.
 230  *  X509_V_ERR_UNSUPPORTED_CONSTRAINT_SYNTAX: bad unsupported constraint syntax.
 231  *  X509_V_ERR_UNSUPPORTED_NAME_SYNTAX: bad or unsupported syntax of name
 232  */
 233
 234 int NAME_CONSTRAINTS_check(X509 *x, NAME_CONSTRAINTS *nc)
 235 {
 236     int r, i, name_count, constraint_count;
 237     X509_NAME *nm;
 238
 239     nm = X509_get_subject_name(x);
 240
 241     /*
 242      * Guard against certificates with an excessive number of names or
 243      * constraints causing a computationally expensive name constraints check.
 244      */
 245     if (!add_lengths(&name_count, X509_NAME_entry_count(nm),
 246                      sk_GENERAL_NAME_num(x->altname))
 247         || !add_lengths(&constraint_count,
 248                         sk_GENERAL_SUBTREE_num(nc->permittedSubtrees),
 249                         sk_GENERAL_SUBTREE_num(nc->excludedSubtrees))
 250         || (name_count > 0 && constraint_count > NAME_CHECK_MAX / name_count))
 251         return X509_V_ERR_UNSPECIFIED;
 252
 253     if (X509_NAME_entry_count(nm) > 0) {
 254         GENERAL_NAME gntmp;
 255         gntmp.type = GEN_DIRNAME;
 256         gntmp.d.directoryName = nm;
 257
 258         r = nc_match(&gntmp, nc);
 259
 260         if (r != X509_V_OK)
 261             return r;
 262
 263         gntmp.type = GEN_EMAIL;
 264
 265         /* Process any email address attributes in subject name */
 266
 267         for (i = -1;;) {
 268             const X509_NAME_ENTRY *ne;
 269
 270             i = X509_NAME_get_index_by_NID(nm, NID_pkcs9_emailAddress, i);
 271             if (i == -1)
 272                 break;
 273             ne = X509_NAME_get_entry(nm, i);
 274             gntmp.d.rfc822Name = X509_NAME_ENTRY_get_data(ne);
 275             if (gntmp.d.rfc822Name->type != V_ASN1_IA5STRING)
 276                 return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
 277
 278             r = nc_match(&gntmp, nc);
 279
 280             if (r != X509_V_OK)
 281                 return r;
 282         }
 283
 284     }
 285
 286     for (i = 0; i < sk_GENERAL_NAME_num(x->altname); i++) {
 287         GENERAL_NAME *gen = sk_GENERAL_NAME_value(x->altname, i);
 288         r = nc_match(gen, nc);
 289         if (r != X509_V_OK)
 290             return r;
 291     }
 292
 293     return X509_V_OK;
 294
 295 }
 296
 297 static int cn2dnsid(ASN1_STRING *cn, unsigned char **dnsid, size_t *idlen)
 298 {
 299     int utf8_length;
 300     unsigned char *utf8_value;
 301     int i;
 302     int isdnsname = 0;
 303
 304     /* Don't leave outputs uninitialized */
 305     *dnsid = NULL;
 306     *idlen = 0;
 307
 308     /*-
 309      * Per RFC 6125, DNS-IDs representing internationalized domain names appear
 310      * in certificates in A-label encoded form:
 311      *
 312      *   https://tools.ietf.org/html/rfc6125#section-6.4.2
 313      *
 314      * The same applies to CNs which are intended to represent DNS names.
 315      * However, while in the SAN DNS-IDs are IA5Strings, as CNs they may be
 316      * needlessly encoded in 16-bit Unicode.  We perform a conversion to UTF-8
 317      * to ensure that we get an ASCII representation of any CNs that are
 318      * representable as ASCII, but just not encoded as ASCII.  The UTF-8 form
 319      * may contain some non-ASCII octets, and that's fine, such CNs are not
 320      * valid legacy DNS names.
 321      *
 322      * Note, 'int' is the return type of ASN1_STRING_to_UTF8() so that's what
 323      * we must use for 'utf8_length'.
 324      */
 325     if ((utf8_length = ASN1_STRING_to_UTF8(&utf8_value, cn)) < 0)
 326         return X509_V_ERR_OUT_OF_MEM;
 327
 328     /*
 329      * Some certificates have had names that include a *trailing* NUL byte.
 330      * Remove these harmless NUL characters. They would otherwise yield false
 331      * alarms with the following embedded NUL check.
 332      */
 333     while (utf8_length > 0 && utf8_value[utf8_length - 1] == '\0')
 334         --utf8_length;
 335
 336     /* Reject *embedded* NULs */
 337     if ((size_t)utf8_length != strlen((char *)utf8_value)) {
 338         OPENSSL_free(utf8_value);
 339         return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
 340     }
 341
 342     /*
 343      * XXX: Deviation from strict DNS name syntax, also check names with '_'
 344      * Check DNS name syntax, any '-' or '.' must be internal,
 345      * and on either side of each '.' we can't have a '-' or '.'.
 346      *
 347      * If the name has just one label, we don't consider it a DNS name.  This
 348      * means that "CN=sometld" cannot be precluded by DNS name constraints, but
 349      * that is not a problem.
 350      */
 351     for (i = 0; i < utf8_length; ++i) {
 352         unsigned char c = utf8_value[i];
 353
 354         if ((c >= 'a' && c <= 'z')
 355             || (c >= 'A' && c <= 'Z')
 356             || (c >= '0' && c <= '9')
 357             || c == '_')
 358             continue;
 359
 360         /* Dot and hyphen cannot be first or last. */
 361         if (i > 0 && i < utf8_length - 1) {
 362             if (c == '-')
 363                 continue;
 364             /*
 365              * Next to a dot the preceding and following characters must not be
 366              * another dot or a hyphen.  Otherwise, record that the name is
 367              * plausible, since it has two or more labels.
 368              */
 369             if (c == '.'
 370                 && utf8_value[i + 1] != '.'
 371                 && utf8_value[i - 1] != '-'
 372                 && utf8_value[i + 1] != '-') {
 373                 isdnsname = 1;
 374                 continue;
 375             }
 376         }
 377         isdnsname = 0;
 378         break;
 379     }
 380
 381     if (isdnsname) {
 382         *dnsid = utf8_value;
 383         *idlen = (size_t)utf8_length;
 384         return X509_V_OK;
 385     }
 386     OPENSSL_free(utf8_value);
 387     return X509_V_OK;
 388 }
 389
 390 /*
 391  * Check CN against DNS-ID name constraints.
 392  */
 393 int NAME_CONSTRAINTS_check_CN(X509 *x, NAME_CONSTRAINTS *nc)
 394 {
 395     int r, i;
 396     const X509_NAME *nm = X509_get_subject_name(x);
 397     ASN1_STRING stmp;
 398     GENERAL_NAME gntmp;
 399
 400     stmp.flags = 0;
 401     stmp.type = V_ASN1_IA5STRING;
 402     gntmp.type = GEN_DNS;
 403     gntmp.d.dNSName = &stmp;
 404
 405     /* Process any commonName attributes in subject name */
 406
 407     for (i = -1;;) {
 408         X509_NAME_ENTRY *ne;
 409         ASN1_STRING *cn;
 410         unsigned char *idval;
 411         size_t idlen;
 412
 413         i = X509_NAME_get_index_by_NID(nm, NID_commonName, i);
 414         if (i == -1)
 415             break;
 416         ne = X509_NAME_get_entry(nm, i);
 417         cn = X509_NAME_ENTRY_get_data(ne);
 418
 419         /* Only process attributes that look like host names */
 420         if ((r = cn2dnsid(cn, &idval, &idlen)) != X509_V_OK)
 421             return r;
 422         if (idlen == 0)
 423             continue;
 424
 425         stmp.length = idlen;
 426         stmp.data = idval;
 427         r = nc_match(&gntmp, nc);
 428         OPENSSL_free(idval);
 429         if (r != X509_V_OK)
 430             return r;
 431     }
 432     return X509_V_OK;
 433 }
 434
 435 /*
 436  * Return nonzero if the GeneralSubtree has valid 'minimum' field
 437  * (must be absent or 0) and valid 'maximum' field (must be absent).
 438  */
 439 static int nc_minmax_valid(GENERAL_SUBTREE *sub) {
 440     BIGNUM *bn = NULL;
 441     int ok = 1;
 442
 443     if (sub->maximum)
 444         ok = 0;
 445
 446     if (sub->minimum) {
 447         bn = ASN1_INTEGER_to_BN(sub->minimum, NULL);
 448         if (bn == NULL || !BN_is_zero(bn))
 449             ok = 0;
 450         BN_free(bn);
 451     }
 452
 453     return ok;
 454 }
 455
 456 static int nc_match(GENERAL_NAME *gen, NAME_CONSTRAINTS *nc)
 457 {
 458     GENERAL_SUBTREE *sub;
 459     int i, r, match = 0;
 460     /*
 461      * We need to compare not gen->type field but an "effective" type because
 462      * the otherName field may contain EAI email address treated specially
 463      * according to RFC 8398, section 6
 464      */
 465     int effective_type = ((gen->type == GEN_OTHERNAME) &&
 466                           (OBJ_obj2nid(gen->d.otherName->type_id) ==
 467                            NID_id_on_SmtpUTF8Mailbox)) ? GEN_EMAIL : gen->type;
 468
 469     /*
 470      * Permitted subtrees: if any subtrees exist of matching the type at
 471      * least one subtree must match.
 472      */
 473
 474     for (i = 0; i < sk_GENERAL_SUBTREE_num(nc->permittedSubtrees); i++) {
 475         sub = sk_GENERAL_SUBTREE_value(nc->permittedSubtrees, i);
 476         if (effective_type != sub->base->type)
 477             continue;
 478         if (!nc_minmax_valid(sub))
 479             return X509_V_ERR_SUBTREE_MINMAX;
 480         /* If we already have a match don't bother trying any more */
 481         if (match == 2)
 482             continue;
 483         if (match == 0)
 484             match = 1;
 485         r = nc_match_single(gen, sub->base);
 486         if (r == X509_V_OK)
 487             match = 2;
 488         else if (r != X509_V_ERR_PERMITTED_VIOLATION)
 489             return r;
 490     }
 491
 492     if (match == 1)
 493         return X509_V_ERR_PERMITTED_VIOLATION;
 494
 495     /* Excluded subtrees: must not match any of these */
 496
 497     for (i = 0; i < sk_GENERAL_SUBTREE_num(nc->excludedSubtrees); i++) {
 498         sub = sk_GENERAL_SUBTREE_value(nc->excludedSubtrees, i);
 499         if (effective_type != sub->base->type)
 500             continue;
 501         if (!nc_minmax_valid(sub))
 502             return X509_V_ERR_SUBTREE_MINMAX;
 503
 504         r = nc_match_single(gen, sub->base);
 505         if (r == X509_V_OK)
 506             return X509_V_ERR_EXCLUDED_VIOLATION;
 507         else if (r != X509_V_ERR_PERMITTED_VIOLATION)
 508             return r;
 509
 510     }
 511
 512     return X509_V_OK;
 513
 514 }
 515
 516 static int nc_match_single(GENERAL_NAME *gen, GENERAL_NAME *base)
 517 {
 518     switch (gen->type) {
 519     case GEN_OTHERNAME:
 520         /*
 521          * We are here only when we have SmtpUTF8 name,
 522          * so we match the value of othername with base->d.rfc822Name
 523          */
 524         return nc_email_eai(gen->d.otherName->value->value.utf8string,
 525                             base->d.rfc822Name);
 526     case GEN_DIRNAME:
 527         return nc_dn(gen->d.directoryName, base->d.directoryName);
 528
 529     case GEN_DNS:
 530         return nc_dns(gen->d.dNSName, base->d.dNSName);
 531
 532     case GEN_EMAIL:
 533         return nc_email(gen->d.rfc822Name, base->d.rfc822Name);
 534
 535     case GEN_URI:
 536         return nc_uri(gen->d.uniformResourceIdentifier,
 537                       base->d.uniformResourceIdentifier);
 538
 539     case GEN_IPADD:
 540         return nc_ip(gen->d.iPAddress, base->d.iPAddress);
 541
 542     default:
 543         return X509_V_ERR_UNSUPPORTED_CONSTRAINT_TYPE;
 544     }
 545
 546 }
 547
 548 /*
 549  * directoryName name constraint matching. The canonical encoding of
 550  * X509_NAME makes this comparison easy. It is matched if the subtree is a
 551  * subset of the name.
 552  */
 553
 554 static int nc_dn(const X509_NAME *nm, const X509_NAME *base)
 555 {
 556     /* Ensure canonical encodings are up to date.  */
 557     if (nm->modified && i2d_X509_NAME(nm, NULL) < 0)
 558         return X509_V_ERR_OUT_OF_MEM;
 559     if (base->modified && i2d_X509_NAME(base, NULL) < 0)
 560         return X509_V_ERR_OUT_OF_MEM;
 561     if (base->canon_enclen > nm->canon_enclen)
 562         return X509_V_ERR_PERMITTED_VIOLATION;
 563     if (memcmp(base->canon_enc, nm->canon_enc, base->canon_enclen))
 564         return X509_V_ERR_PERMITTED_VIOLATION;
 565     return X509_V_OK;
 566 }
 567
 568 static int nc_dns(ASN1_IA5STRING *dns, ASN1_IA5STRING *base)
 569 {
 570     char *baseptr = (char *)base->data;
 571     char *dnsptr = (char *)dns->data;
 572
 573     /* Empty matches everything */
 574     if (*baseptr == '\0')
 575         return X509_V_OK;
 576     /*
 577      * Otherwise can add zero or more components on the left so compare RHS
 578      * and if dns is longer and expect '.' as preceding character.
 579      */
 580     if (dns->length > base->length) {
 581         dnsptr += dns->length - base->length;
 582         if (*baseptr != '.' && dnsptr[-1] != '.')
 583             return X509_V_ERR_PERMITTED_VIOLATION;
 584     }
 585
 586     if (ia5casecmp(baseptr, dnsptr))
 587         return X509_V_ERR_PERMITTED_VIOLATION;
 588
 589     return X509_V_OK;
 590
 591 }
 592
 593 /*
 594  * This function implements comparison between ASCII/U-label in eml
 595  * and A-label in base according to RFC 8398, section 6.
 596  * Convert base to U-label and ASCII-parts of domain names, for base
 597  * Octet-to-octet comparison of `eml` and `base` hostname parts
 598  * (ASCII-parts should be compared in case-insensitive manner)
 599  */
 600 static int nc_email_eai(ASN1_UTF8STRING *eml, ASN1_IA5STRING *base)
 601 {
 602     const char *baseptr = (char *)base->data;
 603     const char *emlptr = (char *)eml->data;
 604     const char *emlat = strrchr(emlptr, '@');
 605
 606     char ulabel[256];
 607     size_t size = sizeof(ulabel) - 1;
 608
 609     if (emlat == NULL)
 610         return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
 611
 612     memset(ulabel, 0, sizeof(ulabel));
 613     /* Special case: initial '.' is RHS match */
 614     if (*baseptr == '.') {
 615         ulabel[0] = '.';
 616         size -= 1;
 617         if (ossl_a2ulabel(baseptr, ulabel + 1, &size) <= 0)
 618             return X509_V_ERR_UNSPECIFIED;
 619
 620         if ((size_t)eml->length > size + 1) {
 621             emlptr += eml->length - (size + 1);
 622             if (ia5casecmp(ulabel, emlptr) == 0)
 623                 return X509_V_OK;
 624         }
 625         return X509_V_ERR_PERMITTED_VIOLATION;
 626     }
 627
 628     emlptr = emlat + 1;
 629     if (ossl_a2ulabel(baseptr, ulabel, &size) <= 0)
 630         return X509_V_ERR_UNSPECIFIED;
 631     /* Just have hostname left to match: case insensitive */
 632     if (ia5casecmp(ulabel, emlptr))
 633         return X509_V_ERR_PERMITTED_VIOLATION;
 634
 635     return X509_V_OK;
 636
 637 }
 638
 639 static int nc_email(ASN1_IA5STRING *eml, ASN1_IA5STRING *base)
 640 {
 641     const char *baseptr = (char *)base->data;
 642     const char *emlptr = (char *)eml->data;
 643
 644     const char *baseat = strrchr(baseptr, '@');
 645     const char *emlat = strrchr(emlptr, '@');
 646     if (!emlat)
 647         return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
 648     /* Special case: initial '.' is RHS match */
 649     if (!baseat && (*baseptr == '.')) {
 650         if (eml->length > base->length) {
 651             emlptr += eml->length - base->length;
 652             if (ia5casecmp(baseptr, emlptr) == 0)
 653                 return X509_V_OK;
 654         }
 655         return X509_V_ERR_PERMITTED_VIOLATION;
 656     }
 657
 658     /* If we have anything before '@' match local part */
 659
 660     if (baseat) {
 661         if (baseat != baseptr) {
 662             if ((baseat - baseptr) != (emlat - emlptr))
 663                 return X509_V_ERR_PERMITTED_VIOLATION;
 664             /* Case sensitive match of local part */
 665             if (strncmp(baseptr, emlptr, emlat - emlptr))
 666                 return X509_V_ERR_PERMITTED_VIOLATION;
 667         }
 668         /* Position base after '@' */
 669         baseptr = baseat + 1;
 670     }
 671     emlptr = emlat + 1;
 672     /* Just have hostname left to match: case insensitive */
 673     if (ia5casecmp(baseptr, emlptr))
 674         return X509_V_ERR_PERMITTED_VIOLATION;
 675
 676     return X509_V_OK;
 677
 678 }
 679
 680 static int nc_uri(ASN1_IA5STRING *uri, ASN1_IA5STRING *base)
 681 {
 682     const char *baseptr = (char *)base->data;
 683     const char *hostptr = (char *)uri->data;
 684     const char *p = strchr(hostptr, ':');
 685     int hostlen;
 686
 687     /* Check for foo:// and skip past it */
 688     if (p == NULL || p[1] != '/' || p[2] != '/')
 689         return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
 690     hostptr = p + 3;
 691
 692     /* Determine length of hostname part of URI */
 693
 694     /* Look for a port indicator as end of hostname first */
 695
 696     p = strchr(hostptr, ':');
 697     /* Otherwise look for trailing slash */
 698     if (p == NULL)
 699         p = strchr(hostptr, '/');
 700
 701     if (p == NULL)
 702         hostlen = strlen(hostptr);
 703     else
 704         hostlen = p - hostptr;
 705
 706     if (hostlen == 0)
 707         return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
 708
 709     /* Special case: initial '.' is RHS match */
 710     if (*baseptr == '.') {
 711         if (hostlen > base->length) {
 712             p = hostptr + hostlen - base->length;
 713             if (ia5ncasecmp(p, baseptr, base->length) == 0)
 714                 return X509_V_OK;
 715         }
 716         return X509_V_ERR_PERMITTED_VIOLATION;
 717     }
 718
 719     if ((base->length != (int)hostlen)
 720         || ia5ncasecmp(hostptr, baseptr, hostlen))
 721         return X509_V_ERR_PERMITTED_VIOLATION;
 722
 723     return X509_V_OK;
 724
 725 }
 726
 727 static int nc_ip(ASN1_OCTET_STRING *ip, ASN1_OCTET_STRING *base)
 728 {
 729     int hostlen, baselen, i;
 730     unsigned char *hostptr, *baseptr, *maskptr;
 731     hostptr = ip->data;
 732     hostlen = ip->length;
 733     baseptr = base->data;
 734     baselen = base->length;
 735
 736     /* Invalid if not IPv4 or IPv6 */
 737     if (!((hostlen == 4) || (hostlen == 16)))
 738         return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
 739     if (!((baselen == 8) || (baselen == 32)))
 740         return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
 741
 742     /* Do not match IPv4 with IPv6 */
 743     if (hostlen * 2 != baselen)
 744         return X509_V_ERR_PERMITTED_VIOLATION;
 745
 746     maskptr = base->data + hostlen;
 747
 748     /* Considering possible not aligned base ipAddress */
 749     /* Not checking for wrong mask definition: i.e.: 255.0.255.0 */
 750     for (i = 0; i < hostlen; i++)
 751         if ((hostptr[i] & maskptr[i]) != (baseptr[i] & maskptr[i]))
 752             return X509_V_ERR_PERMITTED_VIOLATION;
 753
 754     return X509_V_OK;
 755
 756 }