text: /* $OpenBSD: ec_key.c,v 1.10 2015/02/08 22:25:03 miod Exp $ */
  /*
   * Written by Nils Larsch for the OpenSSL project.
   */
  /* ====================================================================
   * Copyright (c) 1998-2005 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
   *    openssl-core@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).
   *
   */
  /* ====================================================================
   * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
   * Portions originally developed by SUN MICROSYSTEMS, INC., and
   * contributed to the OpenSSL project.
   */
  
  #include <string.h>
  
  #include <openssl/opensslconf.h>
  
  #include "ec_lcl.h"
  #include <openssl/err.h>
  
  EC_KEY *
  EC_KEY_new(void)
  {
  	EC_KEY *ret;
  
  	ret = malloc(sizeof(EC_KEY));
  	if (ret == NULL) {
  		ECerr(EC_F_EC_KEY_NEW, ERR_R_MALLOC_FAILURE);
  		return (NULL);
  	}
  	ret->version = 1;
  	ret->flags = 0;
  	ret->group = NULL;
  	ret->pub_key = NULL;
  	ret->priv_key = NULL;
  	ret->enc_flag = 0;
  	ret->conv_form = POINT_CONVERSION_UNCOMPRESSED;
  	ret->references = 1;
  	ret->method_data = NULL;
  	return (ret);
  }
  
  EC_KEY *
  EC_KEY_new_by_curve_name(int nid)
  {
  	EC_KEY *ret = EC_KEY_new();
  	if (ret == NULL)
  		return NULL;
  	ret->group = EC_GROUP_new_by_curve_name(nid);
  	if (ret->group == NULL) {
  		EC_KEY_free(ret);
  		return NULL;
  	}
  	return ret;
  }
  
  void 
  EC_KEY_free(EC_KEY * r)
  {
  	int i;
  
  	if (r == NULL)
  		return;
  
  	i = CRYPTO_add(&r->references, -1, CRYPTO_LOCK_EC);
  	if (i > 0)
  		return;
  
  	EC_GROUP_free(r->group);
  	EC_POINT_free(r->pub_key);
  	BN_clear_free(r->priv_key);
  
  	EC_EX_DATA_free_all_data(&r->method_data);
  
  	OPENSSL_cleanse((void *) r, sizeof(EC_KEY));
  
  	free(r);
  }
  
  EC_KEY *
  EC_KEY_copy(EC_KEY * dest, const EC_KEY * src)
  {
  	EC_EXTRA_DATA *d;
  
  	if (dest == NULL || src == NULL) {
  		ECerr(EC_F_EC_KEY_COPY, ERR_R_PASSED_NULL_PARAMETER);
  		return NULL;
  	}
  	/* copy the parameters */
  	if (src->group) {
  		const EC_METHOD *meth = EC_GROUP_method_of(src->group);
  		/* clear the old group */
  		EC_GROUP_free(dest->group);
  		dest->group = EC_GROUP_new(meth);
  		if (dest->group == NULL)
  			return NULL;
  		if (!EC_GROUP_copy(dest->group, src->group))
  			return NULL;
  	}
  	/* copy the public key */
  	if (src->pub_key && src->group) {
  		EC_POINT_free(dest->pub_key);
  		dest->pub_key = EC_POINT_new(src->group);
  		if (dest->pub_key == NULL)
  			return NULL;
  		if (!EC_POINT_copy(dest->pub_key, src->pub_key))
  			return NULL;
  	}
  	/* copy the private key */
  	if (src->priv_key) {
  		if (dest->priv_key == NULL) {
  			dest->priv_key = BN_new();
  			if (dest->priv_key == NULL)
  				return NULL;
  		}
  		if (!BN_copy(dest->priv_key, src->priv_key))
  			return NULL;
  	}
  	/* copy method/extra data */
  	EC_EX_DATA_free_all_data(&dest->method_data);
  
  	for (d = src->method_data; d != NULL; d = d->next) {
  		void *t = d->dup_func(d->data);
  
  		if (t == NULL)
  			return 0;
  		if (!EC_EX_DATA_set_data(&dest->method_data, t, d->dup_func,
  		    d->free_func, d->clear_free_func))
  			return 0;
  	}
  
  	/* copy the rest */
  	dest->enc_flag = src->enc_flag;
  	dest->conv_form = src->conv_form;
  	dest->version = src->version;
  	dest->flags = src->flags;
  
  	return dest;
  }
  
  EC_KEY *
  EC_KEY_dup(const EC_KEY * ec_key)
  {
  	EC_KEY *ret = EC_KEY_new();
  	if (ret == NULL)
  		return NULL;
  	if (EC_KEY_copy(ret, ec_key) == NULL) {
  		EC_KEY_free(ret);
  		return NULL;
  	}
  	return ret;
  }
  
  int 
  EC_KEY_up_ref(EC_KEY * r)
  {
  	int i = CRYPTO_add(&r->references, 1, CRYPTO_LOCK_EC);
  	return ((i > 1) ? 1 : 0);
  }
  
  int 
  EC_KEY_generate_key(EC_KEY * eckey)
  {
  	int ok = 0;
  	BN_CTX *ctx = NULL;
  	BIGNUM *priv_key = NULL, *order = NULL;
  	EC_POINT *pub_key = NULL;
  
  	if (!eckey || !eckey->group) {
  		ECerr(EC_F_EC_KEY_GENERATE_KEY, ERR_R_PASSED_NULL_PARAMETER);
  		return 0;
  	}
  	if ((order = BN_new()) == NULL)
  		goto err;
  	if ((ctx = BN_CTX_new()) == NULL)
  		goto err;
  
  	if (eckey->priv_key == NULL) {
  		priv_key = BN_new();
  		if (priv_key == NULL)
  			goto err;
  	} else
  		priv_key = eckey->priv_key;
  
  	if (!EC_GROUP_get_order(eckey->group, order, ctx))
  		goto err;
  
  	do
  		if (!BN_rand_range(priv_key, order))
  			goto err;
  	while (BN_is_zero(priv_key));
  
  	if (eckey->pub_key == NULL) {
  		pub_key = EC_POINT_new(eckey->group);
  		if (pub_key == NULL)
  			goto err;
  	} else
  		pub_key = eckey->pub_key;
  
  	if (!EC_POINT_mul(eckey->group, pub_key, priv_key, NULL, NULL, ctx))
  		goto err;
  
  	eckey->priv_key = priv_key;
  	eckey->pub_key = pub_key;
  
  	ok = 1;
  
  err:
  	BN_free(order);
  	if (pub_key != NULL && eckey->pub_key == NULL)
  		EC_POINT_free(pub_key);
  	if (priv_key != NULL && eckey->priv_key == NULL)
  		BN_free(priv_key);
  	BN_CTX_free(ctx);
  	return (ok);
  }
  
  int 
  EC_KEY_check_key(const EC_KEY * eckey)
  {
  	int ok = 0;
  	BN_CTX *ctx = NULL;
  	const BIGNUM *order = NULL;
  	EC_POINT *point = NULL;
  
  	if (!eckey || !eckey->group || !eckey->pub_key) {
  		ECerr(EC_F_EC_KEY_CHECK_KEY, ERR_R_PASSED_NULL_PARAMETER);
  		return 0;
  	}
  	if (EC_POINT_is_at_infinity(eckey->group, eckey->pub_key) > 0) {
  		ECerr(EC_F_EC_KEY_CHECK_KEY, EC_R_POINT_AT_INFINITY);
  		goto err;
  	}
  	if ((ctx = BN_CTX_new()) == NULL)
  		goto err;
  	if ((point = EC_POINT_new(eckey->group)) == NULL)
  		goto err;
  
  	/* testing whether the pub_key is on the elliptic curve */
  	if (EC_POINT_is_on_curve(eckey->group, eckey->pub_key, ctx) <= 0) {
  		ECerr(EC_F_EC_KEY_CHECK_KEY, EC_R_POINT_IS_NOT_ON_CURVE);
  		goto err;
  	}
  	/* testing whether pub_key * order is the point at infinity */
  	order = &eckey->group->order;
  	if (BN_is_zero(order)) {
  		ECerr(EC_F_EC_KEY_CHECK_KEY, EC_R_INVALID_GROUP_ORDER);
  		goto err;
  	}
  	if (!EC_POINT_mul(eckey->group, point, NULL, eckey->pub_key, order, ctx)) {
  		ECerr(EC_F_EC_KEY_CHECK_KEY, ERR_R_EC_LIB);
  		goto err;
  	}
  	if (EC_POINT_is_at_infinity(eckey->group, point) <= 0) {
  		ECerr(EC_F_EC_KEY_CHECK_KEY, EC_R_WRONG_ORDER);
  		goto err;
  	}
  	/*
  	 * in case the priv_key is present : check if generator * priv_key ==
  	 * pub_key
  	 */
  	if (eckey->priv_key) {
  		if (BN_cmp(eckey->priv_key, order) >= 0) {
  			ECerr(EC_F_EC_KEY_CHECK_KEY, EC_R_WRONG_ORDER);
  			goto err;
  		}
  		if (!EC_POINT_mul(eckey->group, point, eckey->priv_key,
  			NULL, NULL, ctx)) {
  			ECerr(EC_F_EC_KEY_CHECK_KEY, ERR_R_EC_LIB);
  			goto err;
  		}
  		if (EC_POINT_cmp(eckey->group, point, eckey->pub_key,
  			ctx) != 0) {
  			ECerr(EC_F_EC_KEY_CHECK_KEY, EC_R_INVALID_PRIVATE_KEY);
  			goto err;
  		}
  	}
  	ok = 1;
  err:
  	BN_CTX_free(ctx);
  	EC_POINT_free(point);
  	return (ok);
  }
  
  int 
  EC_KEY_set_public_key_affine_coordinates(EC_KEY * key, BIGNUM * x, BIGNUM * y)
  {
  	BN_CTX *ctx = NULL;
  	BIGNUM *tx, *ty;
  	EC_POINT *point = NULL;
  	int ok = 0, tmp_nid, is_char_two = 0;
  
  	if (!key || !key->group || !x || !y) {
  		ECerr(EC_F_EC_KEY_SET_PUBLIC_KEY_AFFINE_COORDINATES,
  		    ERR_R_PASSED_NULL_PARAMETER);
  		return 0;
  	}
  	ctx = BN_CTX_new();
  	if (!ctx)
  		goto err;
  
  	point = EC_POINT_new(key->group);
  
  	if (!point)
  		goto err;
  
  	tmp_nid = EC_METHOD_get_field_type(EC_GROUP_method_of(key->group));
  
  	if (tmp_nid == NID_X9_62_characteristic_two_field)
  		is_char_two = 1;
  
  	if ((tx = BN_CTX_get(ctx)) == NULL)
  		goto err;
  	if ((ty = BN_CTX_get(ctx)) == NULL)
  		goto err;
  
  #ifndef OPENSSL_NO_EC2M
  	if (is_char_two) {
  		if (!EC_POINT_set_affine_coordinates_GF2m(key->group, point,
  			x, y, ctx))
  			goto err;
  		if (!EC_POINT_get_affine_coordinates_GF2m(key->group, point,
  			tx, ty, ctx))
  			goto err;
  	} else
  #endif
  	{
  		if (!EC_POINT_set_affine_coordinates_GFp(key->group, point,
  			x, y, ctx))
  			goto err;
  		if (!EC_POINT_get_affine_coordinates_GFp(key->group, point,
  			tx, ty, ctx))
  			goto err;
  	}
  	/*
  	 * Check if retrieved coordinates match originals: if not values are
  	 * out of range.
  	 */
  	if (BN_cmp(x, tx) || BN_cmp(y, ty)) {
  		ECerr(EC_F_EC_KEY_SET_PUBLIC_KEY_AFFINE_COORDINATES,
  		    EC_R_COORDINATES_OUT_OF_RANGE);
  		goto err;
  	}
  	if (!EC_KEY_set_public_key(key, point))
  		goto err;
  
  	if (EC_KEY_check_key(key) == 0)
  		goto err;
  
  	ok = 1;
  
  err:
  	BN_CTX_free(ctx);
  	EC_POINT_free(point);
  	return ok;
  
  }
  
  const EC_GROUP *
  EC_KEY_get0_group(const EC_KEY * key)
  {
  	return key->group;
  }
  
  int 
  EC_KEY_set_group(EC_KEY * key, const EC_GROUP * group)
  {
  	EC_GROUP_free(key->group);
  	key->group = EC_GROUP_dup(group);
  	return (key->group == NULL) ? 0 : 1;
  }
  
  const BIGNUM *
  EC_KEY_get0_private_key(const EC_KEY * key)
  {
  	return key->priv_key;
  }
  
  int 
  EC_KEY_set_private_key(EC_KEY * key, const BIGNUM * priv_key)
  {
  	BN_clear_free(key->priv_key);
  	key->priv_key = BN_dup(priv_key);
  	return (key->priv_key == NULL) ? 0 : 1;
  }
  
  const EC_POINT *
  EC_KEY_get0_public_key(const EC_KEY * key)
  {
  	return key->pub_key;
  }
  
  int 
  EC_KEY_set_public_key(EC_KEY * key, const EC_POINT * pub_key)
  {
  	EC_POINT_free(key->pub_key);
  	key->pub_key = EC_POINT_dup(pub_key, key->group);
  	return (key->pub_key == NULL) ? 0 : 1;
  }
  
  unsigned int 
  EC_KEY_get_enc_flags(const EC_KEY * key)
  {
  	return key->enc_flag;
  }
  
  void 
  EC_KEY_set_enc_flags(EC_KEY * key, unsigned int flags)
  {
  	key->enc_flag = flags;
  }
  
  point_conversion_form_t 
  EC_KEY_get_conv_form(const EC_KEY * key)
  {
  	return key->conv_form;
  }
  
  void 
  EC_KEY_set_conv_form(EC_KEY * key, point_conversion_form_t cform)
  {
  	key->conv_form = cform;
  	if (key->group != NULL)
  		EC_GROUP_set_point_conversion_form(key->group, cform);
  }
  
  void *
  EC_KEY_get_key_method_data(EC_KEY *key,
      void *(*dup_func) (void *),
      void (*free_func) (void *),
      void (*clear_free_func) (void *))
  {
  	void *ret;
  
  	CRYPTO_r_lock(CRYPTO_LOCK_EC);
  	ret = EC_EX_DATA_get_data(key->method_data, dup_func, free_func, clear_free_func);
  	CRYPTO_r_unlock(CRYPTO_LOCK_EC);
  
  	return ret;
  }
  
  void *
  EC_KEY_insert_key_method_data(EC_KEY * key, void *data,
      void *(*dup_func) (void *),
      void (*free_func) (void *),
      void (*clear_free_func) (void *))
  {
  	EC_EXTRA_DATA *ex_data;
  
  	CRYPTO_w_lock(CRYPTO_LOCK_EC);
  	ex_data = EC_EX_DATA_get_data(key->method_data, dup_func, free_func, clear_free_func);
  	if (ex_data == NULL)
  		EC_EX_DATA_set_data(&key->method_data, data, dup_func, free_func, clear_free_func);
  	CRYPTO_w_unlock(CRYPTO_LOCK_EC);
  
  	return ex_data;
  }
  
  void 
  EC_KEY_set_asn1_flag(EC_KEY * key, int flag)
  {
  	if (key->group != NULL)
  		EC_GROUP_set_asn1_flag(key->group, flag);
  }
  
  int 
  EC_KEY_precompute_mult(EC_KEY * key, BN_CTX * ctx)
  {
  	if (key->group == NULL)
  		return 0;
  	return EC_GROUP_precompute_mult(key->group, ctx);
  }
  
  int 
  EC_KEY_get_flags(const EC_KEY * key)
  {
  	return key->flags;
  }
  
  void 
  EC_KEY_set_flags(EC_KEY * key, int flags)
  {
  	key->flags |= flags;
  }
  
  void 
  EC_KEY_clear_flags(EC_KEY * key, int flags)
  {
  	key->flags &= ~flags;
  }
  