text: /* v3_conf.c */
  /*
   * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL project
   * 1999.
   */
  /* ====================================================================
   * Copyright (c) 1999-2002 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). */
  
  /* extension creation utilities */
  
  #include <ctype.h>
  #include <stdio.h>
  #include <string.h>
  
  #include <openssl/conf.h>
  #include <openssl/err.h>
  #include <openssl/mem.h>
  #include <openssl/obj.h>
  #include <openssl/x509.h>
  #include <openssl/x509v3.h>
  
  #include "../internal.h"
  
  static int v3_check_critical(char **value);
  static int v3_check_generic(char **value);
  static X509_EXTENSION *do_ext_nconf(CONF *conf, X509V3_CTX *ctx, int ext_nid,
                                      int crit, char *value);
  static X509_EXTENSION *v3_generic_extension(const char *ext, char *value,
                                              int crit, int type,
                                              X509V3_CTX *ctx);
  static X509_EXTENSION *do_ext_i2d(const X509V3_EXT_METHOD *method,
                                    int ext_nid, int crit, void *ext_struc);
  static unsigned char *generic_asn1(char *value, X509V3_CTX *ctx,
                                     long *ext_len);
  /* CONF *conf:  Config file    */
  /* char *name:  Name    */
  /* char *value:  Value    */
  X509_EXTENSION *X509V3_EXT_nconf(CONF *conf, X509V3_CTX *ctx, char *name,
                                   char *value)
  {
      int crit;
      int ext_type;
      X509_EXTENSION *ret;
      crit = v3_check_critical(&value);
      if ((ext_type = v3_check_generic(&value)))
          return v3_generic_extension(name, value, crit, ext_type, ctx);
      ret = do_ext_nconf(conf, ctx, OBJ_sn2nid(name), crit, value);
      if (!ret) {
          OPENSSL_PUT_ERROR(X509V3, X509V3_R_ERROR_IN_EXTENSION);
          ERR_add_error_data(4, "name=", name, ", value=", value);
      }
      return ret;
  }
  
  /* CONF *conf:  Config file    */
  /* char *value:  Value    */
  X509_EXTENSION *X509V3_EXT_nconf_nid(CONF *conf, X509V3_CTX *ctx, int ext_nid,
                                       char *value)
  {
      int crit;
      int ext_type;
      crit = v3_check_critical(&value);
      if ((ext_type = v3_check_generic(&value)))
          return v3_generic_extension(OBJ_nid2sn(ext_nid),
                                      value, crit, ext_type, ctx);
      return do_ext_nconf(conf, ctx, ext_nid, crit, value);
  }
  
  /* CONF *conf:  Config file    */
  /* char *value:  Value    */
  static X509_EXTENSION *do_ext_nconf(CONF *conf, X509V3_CTX *ctx, int ext_nid,
                                      int crit, char *value)
  {
      const X509V3_EXT_METHOD *method;
      X509_EXTENSION *ext;
      STACK_OF(CONF_VALUE) *nval;
      void *ext_struc;
      if (ext_nid == NID_undef) {
          OPENSSL_PUT_ERROR(X509V3, X509V3_R_UNKNOWN_EXTENSION_NAME);
          return NULL;
      }
      if (!(method = X509V3_EXT_get_nid(ext_nid))) {
          OPENSSL_PUT_ERROR(X509V3, X509V3_R_UNKNOWN_EXTENSION);
          return NULL;
      }
      /* Now get internal extension representation based on type */
      if (method->v2i) {
          if (*value == '@')
              nval = NCONF_get_section(conf, value + 1);
          else
              nval = X509V3_parse_list(value);
          if (sk_CONF_VALUE_num(nval) <= 0) {
              OPENSSL_PUT_ERROR(X509V3, X509V3_R_INVALID_EXTENSION_STRING);
              ERR_add_error_data(4, "name=", OBJ_nid2sn(ext_nid), ",section=",
                                 value);
              return NULL;
          }
          ext_struc = method->v2i(method, ctx, nval);
          if (*value != '@')
              sk_CONF_VALUE_pop_free(nval, X509V3_conf_free);
          if (!ext_struc)
              return NULL;
      } else if (method->s2i) {
          if (!(ext_struc = method->s2i(method, ctx, value)))
              return NULL;
      } else if (method->r2i) {
          if (!ctx->db || !ctx->db_meth) {
              OPENSSL_PUT_ERROR(X509V3, X509V3_R_NO_CONFIG_DATABASE);
              return NULL;
          }
          if (!(ext_struc = method->r2i(method, ctx, value)))
              return NULL;
      } else {
          OPENSSL_PUT_ERROR(X509V3, X509V3_R_EXTENSION_SETTING_NOT_SUPPORTED);
          ERR_add_error_data(2, "name=", OBJ_nid2sn(ext_nid));
          return NULL;
      }
  
      ext = do_ext_i2d(method, ext_nid, crit, ext_struc);
      if (method->it)
          ASN1_item_free(ext_struc, ASN1_ITEM_ptr(method->it));
      else
          method->ext_free(ext_struc);
      return ext;
  
  }
  
  static X509_EXTENSION *do_ext_i2d(const X509V3_EXT_METHOD *method,
                                    int ext_nid, int crit, void *ext_struc)
  {
      unsigned char *ext_der;
      int ext_len;
      ASN1_OCTET_STRING *ext_oct;
      X509_EXTENSION *ext;
      /* Convert internal representation to DER */
      if (method->it) {
          ext_der = NULL;
          ext_len =
              ASN1_item_i2d(ext_struc, &ext_der, ASN1_ITEM_ptr(method->it));
          if (ext_len < 0)
              goto merr;
      } else {
          unsigned char *p;
          ext_len = method->i2d(ext_struc, NULL);
          if (!(ext_der = OPENSSL_malloc(ext_len)))
              goto merr;
          p = ext_der;
          method->i2d(ext_struc, &p);
      }
      if (!(ext_oct = M_ASN1_OCTET_STRING_new()))
          goto merr;
      ext_oct->data = ext_der;
      ext_oct->length = ext_len;
  
      ext = X509_EXTENSION_create_by_NID(NULL, ext_nid, crit, ext_oct);
      if (!ext)
          goto merr;
      M_ASN1_OCTET_STRING_free(ext_oct);
  
      return ext;
  
   merr:
      OPENSSL_PUT_ERROR(X509V3, ERR_R_MALLOC_FAILURE);
      return NULL;
  
  }
  
  /* Given an internal structure, nid and critical flag create an extension */
  
  X509_EXTENSION *X509V3_EXT_i2d(int ext_nid, int crit, void *ext_struc)
  {
      const X509V3_EXT_METHOD *method;
      if (!(method = X509V3_EXT_get_nid(ext_nid))) {
          OPENSSL_PUT_ERROR(X509V3, X509V3_R_UNKNOWN_EXTENSION);
          return NULL;
      }
      return do_ext_i2d(method, ext_nid, crit, ext_struc);
  }
  
  /* Check the extension string for critical flag */
  static int v3_check_critical(char **value)
  {
      char *p = *value;
      if ((strlen(p) < 9) || strncmp(p, "critical,", 9))
          return 0;
      p += 9;
      while (isspace((unsigned char)*p))
          p++;
      *value = p;
      return 1;
  }
  
  /* Check extension string for generic extension and return the type */
  static int v3_check_generic(char **value)
  {
      int gen_type = 0;
      char *p = *value;
      if ((strlen(p) >= 4) && !strncmp(p, "DER:", 4)) {
          p += 4;
          gen_type = 1;
      } else if ((strlen(p) >= 5) && !strncmp(p, "ASN1:", 5)) {
          p += 5;
          gen_type = 2;
      } else
          return 0;
  
      while (isspace((unsigned char)*p))
          p++;
      *value = p;
      return gen_type;
  }
  
  /* Create a generic extension: for now just handle DER type */
  static X509_EXTENSION *v3_generic_extension(const char *ext, char *value,
                                              int crit, int gen_type,
                                              X509V3_CTX *ctx)
  {
      unsigned char *ext_der = NULL;
      long ext_len = 0;
      ASN1_OBJECT *obj = NULL;
      ASN1_OCTET_STRING *oct = NULL;
      X509_EXTENSION *extension = NULL;
      if (!(obj = OBJ_txt2obj(ext, 0))) {
          OPENSSL_PUT_ERROR(X509V3, X509V3_R_EXTENSION_NAME_ERROR);
          ERR_add_error_data(2, "name=", ext);
          goto err;
      }
  
      if (gen_type == 1)
          ext_der = string_to_hex(value, &ext_len);
      else if (gen_type == 2)
          ext_der = generic_asn1(value, ctx, &ext_len);
  
      if (ext_der == NULL) {
          OPENSSL_PUT_ERROR(X509V3, X509V3_R_EXTENSION_VALUE_ERROR);
          ERR_add_error_data(2, "value=", value);
          goto err;
      }
  
      if (!(oct = M_ASN1_OCTET_STRING_new())) {
          OPENSSL_PUT_ERROR(X509V3, ERR_R_MALLOC_FAILURE);
          goto err;
      }
  
      oct->data = ext_der;
      oct->length = ext_len;
      ext_der = NULL;
  
      extension = X509_EXTENSION_create_by_OBJ(NULL, obj, crit, oct);
  
   err:
      ASN1_OBJECT_free(obj);
      M_ASN1_OCTET_STRING_free(oct);
      if (ext_der)
          OPENSSL_free(ext_der);
      return extension;
  
  }
  
  static unsigned char *generic_asn1(char *value, X509V3_CTX *ctx,
                                     long *ext_len)
  {
      ASN1_TYPE *typ;
      unsigned char *ext_der = NULL;
      typ = ASN1_generate_v3(value, ctx);
      if (typ == NULL)
          return NULL;
      *ext_len = i2d_ASN1_TYPE(typ, &ext_der);
      ASN1_TYPE_free(typ);
      return ext_der;
  }
  
  /*
   * This is the main function: add a bunch of extensions based on a config
   * file section to an extension STACK.
   */
  
  int X509V3_EXT_add_nconf_sk(CONF *conf, X509V3_CTX *ctx, char *section,
                              STACK_OF(X509_EXTENSION) **sk)
  {
      X509_EXTENSION *ext;
      STACK_OF(CONF_VALUE) *nval;
      CONF_VALUE *val;
      size_t i;
      if (!(nval = NCONF_get_section(conf, section)))
          return 0;
      for (i = 0; i < sk_CONF_VALUE_num(nval); i++) {
          val = sk_CONF_VALUE_value(nval, i);
          if (!(ext = X509V3_EXT_nconf(conf, ctx, val->name, val->value)))
              return 0;
          if (sk)
              X509v3_add_ext(sk, ext, -1);
          X509_EXTENSION_free(ext);
      }
      return 1;
  }
  
  /*
   * Convenience functions to add extensions to a certificate, CRL and request
   */
  
  int X509V3_EXT_add_nconf(CONF *conf, X509V3_CTX *ctx, char *section,
                           X509 *cert)
  {
      STACK_OF(X509_EXTENSION) **sk = NULL;
      if (cert)
          sk = &cert->cert_info->extensions;
      return X509V3_EXT_add_nconf_sk(conf, ctx, section, sk);
  }
  
  /* Same as above but for a CRL */
  
  int X509V3_EXT_CRL_add_nconf(CONF *conf, X509V3_CTX *ctx, char *section,
                               X509_CRL *crl)
  {
      STACK_OF(X509_EXTENSION) **sk = NULL;
      if (crl)
          sk = &crl->crl->extensions;
      return X509V3_EXT_add_nconf_sk(conf, ctx, section, sk);
  }
  
  /* Add extensions to certificate request */
  
  int X509V3_EXT_REQ_add_nconf(CONF *conf, X509V3_CTX *ctx, char *section,
                               X509_REQ *req)
  {
      STACK_OF(X509_EXTENSION) *extlist = NULL, **sk = NULL;
      int i;
      if (req)
          sk = &extlist;
      i = X509V3_EXT_add_nconf_sk(conf, ctx, section, sk);
      if (!i || !sk)
          return i;
      i = X509_REQ_add_extensions(req, extlist);
      sk_X509_EXTENSION_pop_free(extlist, X509_EXTENSION_free);
      return i;
  }
  
  /* Config database functions */
  
  char *X509V3_get_string(X509V3_CTX *ctx, char *name, char *section)
  {
      if (!ctx->db || !ctx->db_meth || !ctx->db_meth->get_string) {
          OPENSSL_PUT_ERROR(X509V3, X509V3_R_OPERATION_NOT_DEFINED);
          return NULL;
      }
      if (ctx->db_meth->get_string)
          return ctx->db_meth->get_string(ctx->db, name, section);
      return NULL;
  }
  
  STACK_OF(CONF_VALUE) *X509V3_get_section(X509V3_CTX *ctx, char *section)
  {
      if (!ctx->db || !ctx->db_meth || !ctx->db_meth->get_section) {
          OPENSSL_PUT_ERROR(X509V3, X509V3_R_OPERATION_NOT_DEFINED);
          return NULL;
      }
      if (ctx->db_meth->get_section)
          return ctx->db_meth->get_section(ctx->db, section);
      return NULL;
  }
  
  void X509V3_string_free(X509V3_CTX *ctx, char *str)
  {
      if (!str)
          return;
      if (ctx->db_meth->free_string)
          ctx->db_meth->free_string(ctx->db, str);
  }
  
  void X509V3_section_free(X509V3_CTX *ctx, STACK_OF(CONF_VALUE) *section)
  {
      if (!section)
          return;
      if (ctx->db_meth->free_section)
          ctx->db_meth->free_section(ctx->db, section);
  }
  
  static char *nconf_get_string(void *db, char *section, char *value)
  {
      /* TODO(fork): this should return a const value. */
      return (char *)NCONF_get_string(db, section, value);
  }
  
  static STACK_OF(CONF_VALUE) *nconf_get_section(void *db, char *section)
  {
      return NCONF_get_section(db, section);
  }
  
  static const X509V3_CONF_METHOD nconf_method = {
      nconf_get_string,
      nconf_get_section,
      NULL,
      NULL
  };
  
  void X509V3_set_nconf(X509V3_CTX *ctx, CONF *conf)
  {
      ctx->db_meth = &nconf_method;
      ctx->db = conf;
  }
  
  void X509V3_set_ctx(X509V3_CTX *ctx, X509 *issuer, X509 *subj, X509_REQ *req,
                      X509_CRL *crl, int flags)
  {
      ctx->issuer_cert = issuer;
      ctx->subject_cert = subj;
      ctx->crl = crl;
      ctx->subject_req = req;
      ctx->flags = flags;
  }
  