text: /* v3_lib.c */
  /* 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).
   *
   */
  /* X509 v3 extension utilities */
  
  #include <stdio.h>
  #include "cryptlib.h"
  #include <openssl/conf.h>
  #include <openssl/x509v3.h>
  
  #include "ext_dat.h"
  
  static STACK_OF(X509V3_EXT_METHOD) *ext_list = NULL;
  
  static int ext_cmp(const X509V3_EXT_METHOD * const *a,
  		const X509V3_EXT_METHOD * const *b);
  static void ext_list_free(X509V3_EXT_METHOD *ext);
  
  int X509V3_EXT_add(X509V3_EXT_METHOD *ext)
  {
  	if(!ext_list && !(ext_list = sk_X509V3_EXT_METHOD_new(ext_cmp))) {
  		X509V3err(X509V3_F_X509V3_EXT_ADD,ERR_R_MALLOC_FAILURE);
  		return 0;
  	}
  	if(!sk_X509V3_EXT_METHOD_push(ext_list, ext)) {
  		X509V3err(X509V3_F_X509V3_EXT_ADD,ERR_R_MALLOC_FAILURE);
  		return 0;
  	}
  	return 1;
  }
  
  static int ext_cmp(const X509V3_EXT_METHOD * const *a,
  		   const X509V3_EXT_METHOD * const *b)
  {
  	return ((*a)->ext_nid - (*b)->ext_nid);
  }
  
  DECLARE_OBJ_BSEARCH_CMP_FN(const X509V3_EXT_METHOD *, const X509V3_EXT_METHOD *,
  			   ext);
  IMPLEMENT_OBJ_BSEARCH_CMP_FN(const X509V3_EXT_METHOD *,
  			     const X509V3_EXT_METHOD *, ext);
  
  const X509V3_EXT_METHOD *X509V3_EXT_get_nid(int nid)
  {
  	X509V3_EXT_METHOD tmp;
  	const X509V3_EXT_METHOD *t = &tmp, * const *ret;
  	int idx;
  	if(nid < 0) return NULL;
  	tmp.ext_nid = nid;
  	ret = OBJ_bsearch_ext(&t, standard_exts, STANDARD_EXTENSION_COUNT);
  	if(ret) return *ret;
  	if(!ext_list) return NULL;
  	idx = sk_X509V3_EXT_METHOD_find(ext_list, &tmp);
  	if(idx == -1) return NULL;
  	return sk_X509V3_EXT_METHOD_value(ext_list, idx);
  }
  
  const X509V3_EXT_METHOD *X509V3_EXT_get(X509_EXTENSION *ext)
  {
  	int nid;
  	if((nid = OBJ_obj2nid(ext->object)) == NID_undef) return NULL;
  	return X509V3_EXT_get_nid(nid);
  }
  
  
  int X509V3_EXT_add_list(X509V3_EXT_METHOD *extlist)
  {
  	for(;extlist->ext_nid!=-1;extlist++) 
  			if(!X509V3_EXT_add(extlist)) return 0;
  	return 1;
  }
  
  int X509V3_EXT_add_alias(int nid_to, int nid_from)
  {
  	const X509V3_EXT_METHOD *ext;
  	X509V3_EXT_METHOD *tmpext;
  
  	if(!(ext = X509V3_EXT_get_nid(nid_from))) {
  		X509V3err(X509V3_F_X509V3_EXT_ADD_ALIAS,X509V3_R_EXTENSION_NOT_FOUND);
  		return 0;
  	}
  	if(!(tmpext = (X509V3_EXT_METHOD *)OPENSSL_malloc(sizeof(X509V3_EXT_METHOD)))) {
  		X509V3err(X509V3_F_X509V3_EXT_ADD_ALIAS,ERR_R_MALLOC_FAILURE);
  		return 0;
  	}
  	*tmpext = *ext;
  	tmpext->ext_nid = nid_to;
  	tmpext->ext_flags |= X509V3_EXT_DYNAMIC;
  	return X509V3_EXT_add(tmpext);
  }
  
  void X509V3_EXT_cleanup(void)
  {
  	sk_X509V3_EXT_METHOD_pop_free(ext_list, ext_list_free);
  	ext_list = NULL;
  }
  
  static void ext_list_free(X509V3_EXT_METHOD *ext)
  {
  	if(ext->ext_flags & X509V3_EXT_DYNAMIC) OPENSSL_free(ext);
  }
  
  /* Legacy function: we don't need to add standard extensions
   * any more because they are now kept in ext_dat.h.
   */
  
  int X509V3_add_standard_extensions(void)
  {
  	return 1;
  }
  
  /* Return an extension internal structure */
  
  void *X509V3_EXT_d2i(X509_EXTENSION *ext)
  {
  	const X509V3_EXT_METHOD *method;
  	const unsigned char *p;
  
  	if(!(method = X509V3_EXT_get(ext))) return NULL;
  	p = ext->value->data;
  	if(method->it) return ASN1_item_d2i(NULL, &p, ext->value->length, ASN1_ITEM_ptr(method->it));
  	return method->d2i(NULL, &p, ext->value->length);
  }
  
  /* Get critical flag and decoded version of extension from a NID.
   * The "idx" variable returns the last found extension and can
   * be used to retrieve multiple extensions of the same NID.
   * However multiple extensions with the same NID is usually
   * due to a badly encoded certificate so if idx is NULL we
   * choke if multiple extensions exist.
   * The "crit" variable is set to the critical value.
   * The return value is the decoded extension or NULL on
   * error. The actual error can have several different causes,
   * the value of *crit reflects the cause:
   * >= 0, extension found but not decoded (reflects critical value).
   * -1 extension not found.
   * -2 extension occurs more than once.
   */
  
  void *X509V3_get_d2i(STACK_OF(X509_EXTENSION) *x, int nid, int *crit, int *idx)
  {
  	int lastpos, i;
  	X509_EXTENSION *ex, *found_ex = NULL;
  	if(!x) {
  		if(idx) *idx = -1;
  		if(crit) *crit = -1;
  		return NULL;
  	}
  	if(idx) lastpos = *idx + 1;
  	else lastpos = 0;
  	if(lastpos < 0) lastpos = 0;
  	for(i = lastpos; i < sk_X509_EXTENSION_num(x); i++)
  	{
  		ex = sk_X509_EXTENSION_value(x, i);
  		if(OBJ_obj2nid(ex->object) == nid) {
  			if(idx) {
  				*idx = i;
  				found_ex = ex;
  				break;
  			} else if(found_ex) {
  				/* Found more than one */
  				if(crit) *crit = -2;
  				return NULL;
  			}
  			found_ex = ex;
  		}
  	}
  	if(found_ex) {
  		/* Found it */
  		if(crit) *crit = X509_EXTENSION_get_critical(found_ex);
  		return X509V3_EXT_d2i(found_ex);
  	}
  
  	/* Extension not found */
  	if(idx) *idx = -1;
  	if(crit) *crit = -1;
  	return NULL;
  }
  
  /* This function is a general extension append, replace and delete utility.
   * The precise operation is governed by the 'flags' value. The 'crit' and
   * 'value' arguments (if relevant) are the extensions internal structure.
   */
  
  int X509V3_add1_i2d(STACK_OF(X509_EXTENSION) **x, int nid, void *value,
  					int crit, unsigned long flags)
  {
  	int extidx = -1;
  	int errcode;
  	X509_EXTENSION *ext, *extmp;
  	unsigned long ext_op = flags & X509V3_ADD_OP_MASK;
  
  	/* If appending we don't care if it exists, otherwise
  	 * look for existing extension.
  	 */
  	if(ext_op != X509V3_ADD_APPEND)
  		extidx = X509v3_get_ext_by_NID(*x, nid, -1);
  
  	/* See if extension exists */
  	if(extidx >= 0) {
  		/* If keep existing, nothing to do */
  		if(ext_op == X509V3_ADD_KEEP_EXISTING)
  			return 1;
  		/* If default then its an error */
  		if(ext_op == X509V3_ADD_DEFAULT) {
  			errcode = X509V3_R_EXTENSION_EXISTS;
  			goto err;
  		}
  		/* If delete, just delete it */
  		if(ext_op == X509V3_ADD_DELETE) {
  			if(!sk_X509_EXTENSION_delete(*x, extidx)) return -1;
  			return 1;
  		}
  	} else {
  		/* If replace existing or delete, error since 
  		 * extension must exist
  		 */
  		if((ext_op == X509V3_ADD_REPLACE_EXISTING) ||
  		   (ext_op == X509V3_ADD_DELETE)) {
  			errcode = X509V3_R_EXTENSION_NOT_FOUND;
  			goto err;
  		}
  	}
  
  	/* If we get this far then we have to create an extension:
  	 * could have some flags for alternative encoding schemes...
  	 */
  
  	ext = X509V3_EXT_i2d(nid, crit, value);
  
  	if(!ext) {
  		X509V3err(X509V3_F_X509V3_ADD1_I2D, X509V3_R_ERROR_CREATING_EXTENSION);
  		return 0;
  	}
  
  	/* If extension exists replace it.. */
  	if(extidx >= 0) {
  		extmp = sk_X509_EXTENSION_value(*x, extidx);
  		X509_EXTENSION_free(extmp);
  		if(!sk_X509_EXTENSION_set(*x, extidx, ext)) return -1;
  		return 1;
  	}
  
  	if(!*x && !(*x = sk_X509_EXTENSION_new_null())) return -1;
  	if(!sk_X509_EXTENSION_push(*x, ext)) return -1;
  
  	return 1;
  
  	err:
  	if(!(flags & X509V3_ADD_SILENT))
  		X509V3err(X509V3_F_X509V3_ADD1_I2D, errcode);
  	return 0;
  }
  
  IMPLEMENT_STACK_OF(X509V3_EXT_METHOD)
  