text: /* $OpenBSD: v3_akey.c,v 1.18 2016/12/30 15:54:49 jsing Exp $ */
  /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
   * project 1999.
   */
  /* ====================================================================
   * Copyright (c) 1999 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/asn1.h>
  #include <openssl/asn1t.h>
  #include <openssl/conf.h>
  #include <openssl/err.h>
  #include <openssl/x509v3.h>
  
  static STACK_OF(CONF_VALUE) *i2v_AUTHORITY_KEYID(X509V3_EXT_METHOD *method,
      AUTHORITY_KEYID *akeyid, STACK_OF(CONF_VALUE) *extlist);
  static AUTHORITY_KEYID *v2i_AUTHORITY_KEYID(X509V3_EXT_METHOD *method,
      X509V3_CTX *ctx, STACK_OF(CONF_VALUE) *values);
  
  const X509V3_EXT_METHOD v3_akey_id = {
  	.ext_nid = NID_authority_key_identifier,
  	.ext_flags = X509V3_EXT_MULTILINE,
  	.it = &AUTHORITY_KEYID_it,
  	.ext_new = NULL,
  	.ext_free = NULL,
  	.d2i = NULL,
  	.i2d = NULL,
  	.i2s = NULL,
  	.s2i = NULL,
  	.i2v = (X509V3_EXT_I2V)i2v_AUTHORITY_KEYID,
  	.v2i = (X509V3_EXT_V2I)v2i_AUTHORITY_KEYID,
  	.i2r = NULL,
  	.r2i = NULL,
  	.usr_data = NULL,
  };
  
  static
  STACK_OF(CONF_VALUE) *i2v_AUTHORITY_KEYID(X509V3_EXT_METHOD *method,
      AUTHORITY_KEYID *akeyid, STACK_OF(CONF_VALUE) *extlist)
  {
  	char *tmp;
  
  	if (akeyid->keyid) {
  		tmp = hex_to_string(akeyid->keyid->data, akeyid->keyid->length);
  		X509V3_add_value("keyid", tmp, &extlist);
  		free(tmp);
  	}
  	if (akeyid->issuer)
  		extlist = i2v_GENERAL_NAMES(NULL, akeyid->issuer, extlist);
  	if (akeyid->serial) {
  		tmp = hex_to_string(akeyid->serial->data,
  		    akeyid->serial->length);
  		X509V3_add_value("serial", tmp, &extlist);
  		free(tmp);
  	}
  	return extlist;
  }
  
  /* Currently two options:
   * keyid: use the issuers subject keyid, the value 'always' means its is
   * an error if the issuer certificate doesn't have a key id.
   * issuer: use the issuers cert issuer and serial number. The default is
   * to only use this if keyid is not present. With the option 'always'
   * this is always included.
   */
  
  static AUTHORITY_KEYID *
  v2i_AUTHORITY_KEYID(X509V3_EXT_METHOD *method, X509V3_CTX *ctx,
      STACK_OF(CONF_VALUE) *values)
  {
  	char keyid = 0, issuer = 0;
  	int i;
  	CONF_VALUE *cnf;
  	ASN1_OCTET_STRING *ikeyid = NULL;
  	X509_NAME *isname = NULL;
  	STACK_OF(GENERAL_NAME) *gens = NULL;
  	GENERAL_NAME *gen = NULL;
  	ASN1_INTEGER *serial = NULL;
  	X509_EXTENSION *ext;
  	X509 *cert;
  	AUTHORITY_KEYID *akeyid = NULL;
  
  	for (i = 0; i < sk_CONF_VALUE_num(values); i++) {
  		cnf = sk_CONF_VALUE_value(values, i);
  		if (!strcmp(cnf->name, "keyid")) {
  			keyid = 1;
  			if (cnf->value && !strcmp(cnf->value, "always"))
  				keyid = 2;
  		}
  		else if (!strcmp(cnf->name, "issuer")) {
  			issuer = 1;
  			if (cnf->value && !strcmp(cnf->value, "always"))
  				issuer = 2;
  		} else {
  			X509V3error(X509V3_R_UNKNOWN_OPTION);
  			ERR_asprintf_error_data("name=%s", cnf->name);
  			return NULL;
  		}
  	}
  
  	if (!ctx || !ctx->issuer_cert) {
  		if (ctx && (ctx->flags == CTX_TEST))
  			return AUTHORITY_KEYID_new();
  		X509V3error(X509V3_R_NO_ISSUER_CERTIFICATE);
  		return NULL;
  	}
  
  	cert = ctx->issuer_cert;
  
  	if (keyid) {
  		i = X509_get_ext_by_NID(cert, NID_subject_key_identifier, -1);
  		if ((i >= 0)  && (ext = X509_get_ext(cert, i)))
  			ikeyid = X509V3_EXT_d2i(ext);
  		if (keyid == 2 && !ikeyid) {
  			X509V3error(X509V3_R_UNABLE_TO_GET_ISSUER_KEYID);
  			return NULL;
  		}
  	}
  
  	if ((issuer && !ikeyid) || (issuer == 2)) {
  		isname = X509_NAME_dup(X509_get_issuer_name(cert));
  		serial = ASN1_INTEGER_dup(X509_get_serialNumber(cert));
  		if (!isname || !serial) {
  			X509V3error(X509V3_R_UNABLE_TO_GET_ISSUER_DETAILS);
  			goto err;
  		}
  	}
  
  	if (!(akeyid = AUTHORITY_KEYID_new()))
  		goto err;
  
  	if (isname) {
  		if (!(gens = sk_GENERAL_NAME_new_null()) ||
  		    !(gen = GENERAL_NAME_new()) ||
  		    !sk_GENERAL_NAME_push(gens, gen)) {
  			X509V3error(ERR_R_MALLOC_FAILURE);
  			goto err;
  		}
  		gen->type = GEN_DIRNAME;
  		gen->d.dirn = isname;
  	}
  
  	akeyid->issuer = gens;
  	akeyid->serial = serial;
  	akeyid->keyid = ikeyid;
  
  	return akeyid;
  
  err:
  	AUTHORITY_KEYID_free(akeyid);
  	GENERAL_NAME_free(gen);
  	sk_GENERAL_NAME_free(gens);
  	X509_NAME_free(isname);
  	ASN1_INTEGER_free(serial);
  	ASN1_OCTET_STRING_free(ikeyid);
  	return NULL;
  }
  