text: /* v3_ncons.c */
  /*
   * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
   * project.
   */
  /* ====================================================================
   * Copyright (c) 2003 The OpenSSL Project.  All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   *
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   *
   * 3. All advertising materials mentioning features or use of this
   *    software must display the following acknowledgment:
   *    "This product includes software developed by the OpenSSL Project
   *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
   *
   * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
   *    endorse or promote products derived from this software without
   *    prior written permission. For written permission, please contact
   *    licensing@OpenSSL.org.
   *
   * 5. Products derived from this software may not be called "OpenSSL"
   *    nor may "OpenSSL" appear in their names without prior written
   *    permission of the OpenSSL Project.
   *
   * 6. Redistributions of any form whatsoever must retain the following
   *    acknowledgment:
   *    "This product includes software developed by the OpenSSL Project
   *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
   *
   * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
   * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
   * OF THE POSSIBILITY OF SUCH DAMAGE.
   * ====================================================================
   *
   * This product includes cryptographic software written by Eric Young
   * (eay@cryptsoft.com).  This product includes software written by Tim
   * Hudson (tjh@cryptsoft.com). */
  
  #include <stdio.h>
  #include <string.h>
  
  #include <openssl/asn1t.h>
  #include <openssl/conf.h>
  #include <openssl/err.h>
  #include <openssl/mem.h>
  #include <openssl/obj.h>
  #include <openssl/x509v3.h>
  
  #include "../internal.h"
  
  
  static void *v2i_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method,
                                    X509V3_CTX *ctx,
                                    STACK_OF(CONF_VALUE) *nval);
  static int i2r_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method, void *a,
                                  BIO *bp, int ind);
  static int do_i2r_name_constraints(const X509V3_EXT_METHOD *method,
                                     STACK_OF(GENERAL_SUBTREE) *trees, BIO *bp,
                                     int ind, const char *name);
  static int print_nc_ipadd(BIO *bp, ASN1_OCTET_STRING *ip);
  
  static int nc_match(GENERAL_NAME *gen, NAME_CONSTRAINTS *nc);
  static int nc_match_single(GENERAL_NAME *sub, GENERAL_NAME *gen);
  static int nc_dn(X509_NAME *sub, X509_NAME *nm);
  static int nc_dns(ASN1_IA5STRING *sub, ASN1_IA5STRING *dns);
  static int nc_email(ASN1_IA5STRING *sub, ASN1_IA5STRING *eml);
  static int nc_uri(ASN1_IA5STRING *uri, ASN1_IA5STRING *base);
  
  const X509V3_EXT_METHOD v3_name_constraints = {
      NID_name_constraints, 0,
      ASN1_ITEM_ref(NAME_CONSTRAINTS),
      0, 0, 0, 0,
      0, 0,
      0, v2i_NAME_CONSTRAINTS,
      i2r_NAME_CONSTRAINTS, 0,
      NULL
  };
  
  ASN1_SEQUENCE(GENERAL_SUBTREE) = {
          ASN1_SIMPLE(GENERAL_SUBTREE, base, GENERAL_NAME),
          ASN1_IMP_OPT(GENERAL_SUBTREE, minimum, ASN1_INTEGER, 0),
          ASN1_IMP_OPT(GENERAL_SUBTREE, maximum, ASN1_INTEGER, 1)
  } ASN1_SEQUENCE_END(GENERAL_SUBTREE)
  
  ASN1_SEQUENCE(NAME_CONSTRAINTS) = {
          ASN1_IMP_SEQUENCE_OF_OPT(NAME_CONSTRAINTS, permittedSubtrees,
                                                          GENERAL_SUBTREE, 0),
          ASN1_IMP_SEQUENCE_OF_OPT(NAME_CONSTRAINTS, excludedSubtrees,
                                                          GENERAL_SUBTREE, 1),
  } ASN1_SEQUENCE_END(NAME_CONSTRAINTS)
  
  
  IMPLEMENT_ASN1_ALLOC_FUNCTIONS(GENERAL_SUBTREE)
  IMPLEMENT_ASN1_ALLOC_FUNCTIONS(NAME_CONSTRAINTS)
  
  static void *v2i_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method,
                                    X509V3_CTX *ctx, STACK_OF(CONF_VALUE) *nval)
  {
      size_t i;
      CONF_VALUE tval, *val;
      STACK_OF(GENERAL_SUBTREE) **ptree = NULL;
      NAME_CONSTRAINTS *ncons = NULL;
      GENERAL_SUBTREE *sub = NULL;
      ncons = NAME_CONSTRAINTS_new();
      if (!ncons)
          goto memerr;
      for (i = 0; i < sk_CONF_VALUE_num(nval); i++) {
          val = sk_CONF_VALUE_value(nval, i);
          if (!strncmp(val->name, "permitted", 9) && val->name[9]) {
              ptree = &ncons->permittedSubtrees;
              tval.name = val->name + 10;
          } else if (!strncmp(val->name, "excluded", 8) && val->name[8]) {
              ptree = &ncons->excludedSubtrees;
              tval.name = val->name + 9;
          } else {
              OPENSSL_PUT_ERROR(X509V3, X509V3_R_INVALID_SYNTAX);
              goto err;
          }
          tval.value = val->value;
          sub = GENERAL_SUBTREE_new();
          if (!v2i_GENERAL_NAME_ex(sub->base, method, ctx, &tval, 1))
              goto err;
          if (!*ptree)
              *ptree = sk_GENERAL_SUBTREE_new_null();
          if (!*ptree || !sk_GENERAL_SUBTREE_push(*ptree, sub))
              goto memerr;
          sub = NULL;
      }
  
      return ncons;
  
   memerr:
      OPENSSL_PUT_ERROR(X509V3, ERR_R_MALLOC_FAILURE);
   err:
      if (ncons)
          NAME_CONSTRAINTS_free(ncons);
      if (sub)
          GENERAL_SUBTREE_free(sub);
  
      return NULL;
  }
  
  static int i2r_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method, void *a,
                                  BIO *bp, int ind)
  {
      NAME_CONSTRAINTS *ncons = a;
      do_i2r_name_constraints(method, ncons->permittedSubtrees,
                              bp, ind, "Permitted");
      do_i2r_name_constraints(method, ncons->excludedSubtrees,
                              bp, ind, "Excluded");
      return 1;
  }
  
  static int do_i2r_name_constraints(const X509V3_EXT_METHOD *method,
                                     STACK_OF(GENERAL_SUBTREE) *trees,
                                     BIO *bp, int ind, const char *name)
  {
      GENERAL_SUBTREE *tree;
      size_t i;
      if (sk_GENERAL_SUBTREE_num(trees) > 0)
          BIO_printf(bp, "%*s%s:\n", ind, "", name);
      for (i = 0; i < sk_GENERAL_SUBTREE_num(trees); i++) {
          tree = sk_GENERAL_SUBTREE_value(trees, i);
          BIO_printf(bp, "%*s", ind + 2, "");
          if (tree->base->type == GEN_IPADD)
              print_nc_ipadd(bp, tree->base->d.ip);
          else
              GENERAL_NAME_print(bp, tree->base);
          BIO_puts(bp, "\n");
      }
      return 1;
  }
  
  static int print_nc_ipadd(BIO *bp, ASN1_OCTET_STRING *ip)
  {
      int i, len;
      unsigned char *p;
      p = ip->data;
      len = ip->length;
      BIO_puts(bp, "IP:");
      if (len == 8) {
          BIO_printf(bp, "%d.%d.%d.%d/%d.%d.%d.%d",
                     p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7]);
      } else if (len == 32) {
          for (i = 0; i < 16; i++) {
              BIO_printf(bp, "%X", p[0] << 8 | p[1]);
              p += 2;
              if (i == 7)
                  BIO_puts(bp, "/");
              else if (i != 15)
                  BIO_puts(bp, ":");
          }
      } else
          BIO_printf(bp, "IP Address:<invalid>");
      return 1;
  }
  
  /*-
   * Check a certificate conforms to a specified set of constraints.
   * Return values:
   *   X509_V_OK: All constraints obeyed.
   *   X509_V_ERR_PERMITTED_VIOLATION: Permitted subtree violation.
   *   X509_V_ERR_EXCLUDED_VIOLATION: Excluded subtree violation.
   *   X509_V_ERR_SUBTREE_MINMAX: Min or max values present and matching type.
   *   X509_V_ERR_UNSPECIFIED: Unspecified error.
   *   X509_V_ERR_UNSUPPORTED_CONSTRAINT_TYPE: Unsupported constraint type.
   *   X509_V_ERR_UNSUPPORTED_CONSTRAINT_SYNTAX: Bad or unsupported constraint
   *     syntax.
   *   X509_V_ERR_UNSUPPORTED_NAME_SYNTAX: Bad or unsupported syntax of name.
   */
  
  int NAME_CONSTRAINTS_check(X509 *x, NAME_CONSTRAINTS *nc)
  {
      int r, i;
      size_t j;
      X509_NAME *nm;
  
      nm = X509_get_subject_name(x);
  
      /* Guard against certificates with an excessive number of names or
       * constraints causing a computationally expensive name constraints
       * check. */
      size_t name_count =
          X509_NAME_entry_count(nm) + sk_GENERAL_NAME_num(x->altname);
      size_t constraint_count = sk_GENERAL_SUBTREE_num(nc->permittedSubtrees) +
                                sk_GENERAL_SUBTREE_num(nc->excludedSubtrees);
      size_t check_count = constraint_count * name_count;
      if (name_count < (size_t)X509_NAME_entry_count(nm) ||
          constraint_count < sk_GENERAL_SUBTREE_num(nc->permittedSubtrees) ||
          (constraint_count && check_count / constraint_count != name_count) ||
          check_count > 1 << 20) {
        return X509_V_ERR_UNSPECIFIED;
      }
  
      if (X509_NAME_entry_count(nm) > 0) {
          GENERAL_NAME gntmp;
          gntmp.type = GEN_DIRNAME;
          gntmp.d.directoryName = nm;
  
          r = nc_match(&gntmp, nc);
  
          if (r != X509_V_OK)
              return r;
  
          gntmp.type = GEN_EMAIL;
  
          /* Process any email address attributes in subject name */
  
          for (i = -1;;) {
              X509_NAME_ENTRY *ne;
              i = X509_NAME_get_index_by_NID(nm, NID_pkcs9_emailAddress, i);
              if (i == -1)
                  break;
              ne = X509_NAME_get_entry(nm, i);
              gntmp.d.rfc822Name = X509_NAME_ENTRY_get_data(ne);
              if (gntmp.d.rfc822Name->type != V_ASN1_IA5STRING)
                  return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
  
              r = nc_match(&gntmp, nc);
  
              if (r != X509_V_OK)
                  return r;
          }
  
      }
  
      for (j = 0; j < sk_GENERAL_NAME_num(x->altname); j++) {
          GENERAL_NAME *gen = sk_GENERAL_NAME_value(x->altname, j);
          r = nc_match(gen, nc);
          if (r != X509_V_OK)
              return r;
      }
  
      return X509_V_OK;
  
  }
  
  static int nc_match(GENERAL_NAME *gen, NAME_CONSTRAINTS *nc)
  {
      GENERAL_SUBTREE *sub;
      int r, match = 0;
      size_t i;
  
      /*
       * Permitted subtrees: if any subtrees exist of matching the type at
       * least one subtree must match.
       */
  
      for (i = 0; i < sk_GENERAL_SUBTREE_num(nc->permittedSubtrees); i++) {
          sub = sk_GENERAL_SUBTREE_value(nc->permittedSubtrees, i);
          if (gen->type != sub->base->type)
              continue;
          if (sub->minimum || sub->maximum)
              return X509_V_ERR_SUBTREE_MINMAX;
          /* If we already have a match don't bother trying any more */
          if (match == 2)
              continue;
          if (match == 0)
              match = 1;
          r = nc_match_single(gen, sub->base);
          if (r == X509_V_OK)
              match = 2;
          else if (r != X509_V_ERR_PERMITTED_VIOLATION)
              return r;
      }
  
      if (match == 1)
          return X509_V_ERR_PERMITTED_VIOLATION;
  
      /* Excluded subtrees: must not match any of these */
  
      for (i = 0; i < sk_GENERAL_SUBTREE_num(nc->excludedSubtrees); i++) {
          sub = sk_GENERAL_SUBTREE_value(nc->excludedSubtrees, i);
          if (gen->type != sub->base->type)
              continue;
          if (sub->minimum || sub->maximum)
              return X509_V_ERR_SUBTREE_MINMAX;
  
          r = nc_match_single(gen, sub->base);
          if (r == X509_V_OK)
              return X509_V_ERR_EXCLUDED_VIOLATION;
          else if (r != X509_V_ERR_PERMITTED_VIOLATION)
              return r;
  
      }
  
      return X509_V_OK;
  
  }
  
  static int nc_match_single(GENERAL_NAME *gen, GENERAL_NAME *base)
  {
      switch (base->type) {
      case GEN_DIRNAME:
          return nc_dn(gen->d.directoryName, base->d.directoryName);
  
      case GEN_DNS:
          return nc_dns(gen->d.dNSName, base->d.dNSName);
  
      case GEN_EMAIL:
          return nc_email(gen->d.rfc822Name, base->d.rfc822Name);
  
      case GEN_URI:
          return nc_uri(gen->d.uniformResourceIdentifier,
                        base->d.uniformResourceIdentifier);
  
      default:
          return X509_V_ERR_UNSUPPORTED_CONSTRAINT_TYPE;
      }
  
  }
  
  /*
   * directoryName name constraint matching. The canonical encoding of
   * X509_NAME makes this comparison easy. It is matched if the subtree is a
   * subset of the name.
   */
  
  static int nc_dn(X509_NAME *nm, X509_NAME *base)
  {
      /* Ensure canonical encodings are up to date.  */
      if (nm->modified && i2d_X509_NAME(nm, NULL) < 0)
          return X509_V_ERR_OUT_OF_MEM;
      if (base->modified && i2d_X509_NAME(base, NULL) < 0)
          return X509_V_ERR_OUT_OF_MEM;
      if (base->canon_enclen > nm->canon_enclen)
          return X509_V_ERR_PERMITTED_VIOLATION;
      if (OPENSSL_memcmp(base->canon_enc, nm->canon_enc, base->canon_enclen))
          return X509_V_ERR_PERMITTED_VIOLATION;
      return X509_V_OK;
  }
  
  static int starts_with(const CBS *cbs, uint8_t c)
  {
      return CBS_len(cbs) > 0 && CBS_data(cbs)[0] == c;
  }
  
  static int equal_case(const CBS *a, const CBS *b)
  {
      if (CBS_len(a) != CBS_len(b)) {
          return 0;
      }
      /* Note we cannot use |OPENSSL_strncasecmp| because that would stop
       * iterating at NUL. */
      const uint8_t *a_data = CBS_data(a), *b_data = CBS_data(b);
      for (size_t i = 0; i < CBS_len(a); i++) {
          if (OPENSSL_tolower(a_data[i]) != OPENSSL_tolower(b_data[i])) {
              return 0;
          }
      }
      return 1;
  }
  
  static int has_suffix_case(const CBS *a, const CBS *b)
  {
      if (CBS_len(a) < CBS_len(b)) {
          return 0;
      }
      CBS copy = *a;
      CBS_skip(&copy, CBS_len(a) - CBS_len(b));
      return equal_case(&copy, b);
  }
  
  static int nc_dns(ASN1_IA5STRING *dns, ASN1_IA5STRING *base)
  {
      CBS dns_cbs, base_cbs;
      CBS_init(&dns_cbs, dns->data, dns->length);
      CBS_init(&base_cbs, base->data, base->length);
  
      /* Empty matches everything */
      if (CBS_len(&base_cbs) == 0) {
          return X509_V_OK;
      }
  
      /* If |base_cbs| begins with a '.', do a simple suffix comparison. This is
       * not part of RFC5280, but is part of OpenSSL's original behavior. */
      if (starts_with(&base_cbs, '.')) {
          if (has_suffix_case(&dns_cbs, &base_cbs)) {
              return X509_V_OK;
          }
          return X509_V_ERR_PERMITTED_VIOLATION;
      }
  
      /*
       * Otherwise can add zero or more components on the left so compare RHS
       * and if dns is longer and expect '.' as preceding character.
       */
      if (CBS_len(&dns_cbs) > CBS_len(&base_cbs)) {
          uint8_t dot;
          if (!CBS_skip(&dns_cbs, CBS_len(&dns_cbs) - CBS_len(&base_cbs) - 1) ||
              !CBS_get_u8(&dns_cbs, &dot) ||
              dot != '.') {
              return X509_V_ERR_PERMITTED_VIOLATION;
          }
      }
  
      if (!equal_case(&dns_cbs, &base_cbs)) {
          return X509_V_ERR_PERMITTED_VIOLATION;
      }
  
      return X509_V_OK;
  
  }
  
  static int nc_email(ASN1_IA5STRING *eml, ASN1_IA5STRING *base)
  {
      CBS eml_cbs, base_cbs;
      CBS_init(&eml_cbs, eml->data, eml->length);
      CBS_init(&base_cbs, base->data, base->length);
  
      /* TODO(davidben): In OpenSSL 1.1.1, this switched from the first '@' to the
       * last one. Match them here, or perhaps do an actual parse. Looks like
       * multiple '@'s may be allowed in quoted strings. */
      CBS eml_local, base_local;
      if (!CBS_get_until_first(&eml_cbs, &eml_local, '@')) {
          return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
      }
      int base_has_at = CBS_get_until_first(&base_cbs, &base_local, '@');
  
      /* Special case: inital '.' is RHS match */
      if (!base_has_at && starts_with(&base_cbs, '.')) {
          if (has_suffix_case(&eml_cbs, &base_cbs)) {
              return X509_V_OK;
          }
          return X509_V_ERR_PERMITTED_VIOLATION;
      }
  
      /* If we have anything before '@' match local part */
      if (base_has_at) {
          /* TODO(davidben): This interprets a constraint of "@example.com" as
           * "example.com", which is not part of RFC5280. */
          if (CBS_len(&base_local) > 0) {
              /* Case sensitive match of local part */
              if (!CBS_mem_equal(&base_local, CBS_data(&eml_local),
                                 CBS_len(&eml_local))) {
                  return X509_V_ERR_PERMITTED_VIOLATION;
              }
          }
          /* Position base after '@' */
          assert(starts_with(&base_cbs, '@'));
          CBS_skip(&base_cbs, 1);
      }
  
      /* Just have hostname left to match: case insensitive */
      assert(starts_with(&eml_cbs, '@'));
      CBS_skip(&eml_cbs, 1);
      if (!equal_case(&base_cbs, &eml_cbs)) {
          return X509_V_ERR_PERMITTED_VIOLATION;
      }
  
      return X509_V_OK;
  }
  
  static int nc_uri(ASN1_IA5STRING *uri, ASN1_IA5STRING *base)
  {
      CBS uri_cbs, base_cbs;
      CBS_init(&uri_cbs, uri->data, uri->length);
      CBS_init(&base_cbs, base->data, base->length);
  
      /* Check for foo:// and skip past it */
      CBS scheme;
      uint8_t byte;
      if (!CBS_get_until_first(&uri_cbs, &scheme, ':') ||
          !CBS_skip(&uri_cbs, 1) ||  // Skip the colon
          !CBS_get_u8(&uri_cbs, &byte) || byte != '/' ||
          !CBS_get_u8(&uri_cbs, &byte) || byte != '/') {
          return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
      }
  
      /* Look for a port indicator as end of hostname first. Otherwise look for
       * trailing slash, or the end of the string.
       * TODO(davidben): This is not a correct URI parser and mishandles IPv6
       * literals. */
      CBS host;
      if (!CBS_get_until_first(&uri_cbs, &host, ':') &&
          !CBS_get_until_first(&uri_cbs, &host, '/')) {
          host = uri_cbs;
      }
  
      if (CBS_len(&host) == 0) {
          return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
      }
  
      /* Special case: inital '.' is RHS match */
      if (starts_with(&base_cbs, '.')) {
          if (has_suffix_case(&host, &base_cbs)) {
              return X509_V_OK;
          }
          return X509_V_ERR_PERMITTED_VIOLATION;
      }
  
      if (!equal_case(&base_cbs, &host)) {
          return X509_V_ERR_PERMITTED_VIOLATION;
      }
  
      return X509_V_OK;
  
  }
  