ec_ameth.c

/* Written by Dr Stephen N Henson (shenson@bigfoot.com) for the OpenSSL
 * project 2006.
 */
/* ====================================================================
 * Copyright (c) 2006 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 "cryptlib.h"
#include <openssl/x509.h>
#include <openssl/ec.h>
#include "asn1_locl.h"

static int eckey_param2type(int *pptype, void **ppval, EC_KEY *ec_key)
	{
	const EC_GROUP  *group;
	int nid;
	if (ec_key == NULL || (group = EC_KEY_get0_group(ec_key)) == NULL) 
	{
		ECerr(EC_F_ECKEY_PARAM2TYPE, EC_R_MISSING_PARAMETERS);
		return 0;
	}
	if (EC_GROUP_get_asn1_flag(group)
                     && (nid = EC_GROUP_get_curve_name(group)))
		/* we have a 'named curve' => just set the OID */
		{
		*ppval = OBJ_nid2obj(nid);
		*pptype = V_ASN1_OBJECT;
		}
	else	/* explicit parameters */
		{
		ASN1_STRING *pstr = NULL;
		pstr = ASN1_STRING_new();
		if (!pstr)
			return 0;
		pstr->length = i2d_ECParameters(ec_key, &pstr->data);
		if (pstr->length < 0)
			{
			ASN1_STRING_free(pstr);
			ECerr(EC_F_ECKEY_PARAM2TYPE, ERR_R_EC_LIB);
			return 0;
			}
		*ppval = pstr;
		*pptype = V_ASN1_SEQUENCE;
		}
	return 1;
	}

static int eckey_pub_encode(X509_PUBKEY *pk, const EVP_PKEY *pkey)
	{
	EC_KEY *ec_key = pkey->pkey.ec;
	void *pval = NULL;
	int ptype;
	unsigned char *penc = NULL, *p;
	int penclen;

	if (!eckey_param2type(&ptype, &pval, ec_key))
		{
		ECerr(EC_F_ECKEY_PUB_ENCODE, ERR_R_EC_LIB);
		return 0;
		}
	penclen = i2o_ECPublicKey(ec_key, NULL);
	if (penclen <= 0)
		goto err;
	penc = OPENSSL_malloc(penclen);
	if (!penc)
		goto err;
	p = penc;
	penclen = i2o_ECPublicKey(ec_key, &p);
	if (penclen <= 0)
		goto err;
	if (X509_PUBKEY_set0_param(pk, OBJ_nid2obj(EVP_PKEY_EC),
				ptype, pval, penc, penclen))
		return 1;
	err:
	if (ptype == V_ASN1_OBJECT)
		ASN1_OBJECT_free(pval);
	else
		ASN1_STRING_free(pval);
	if (penc)
		OPENSSL_free(penc);
	return 0;
	}

static EC_KEY *eckey_type2param(int ptype, void *pval)
	{
	EC_KEY *eckey = NULL;
	if (ptype == V_ASN1_SEQUENCE)
		{
		ASN1_STRING *pstr = pval;
		const unsigned char *pm = NULL;
		int pmlen;
		pm = pstr->data;
		pmlen = pstr->length;
		if (!(eckey = d2i_ECParameters(NULL, &pm, pmlen)))
			{
			ECerr(EC_F_ECKEY_TYPE2PARAM, EC_R_DECODE_ERROR);
			goto ecerr;
			}
		}
	else if (ptype == V_ASN1_OBJECT)
		{
		ASN1_OBJECT *poid = pval;
		EC_GROUP *group;

		/* type == V_ASN1_OBJECT => the parameters are given
		 * by an asn1 OID
		 */
		if ((eckey = EC_KEY_new()) == NULL)
			{
			ECerr(EC_F_ECKEY_TYPE2PARAM, ERR_R_MALLOC_FAILURE);
			goto ecerr;
			}
		group = EC_GROUP_new_by_curve_name(OBJ_obj2nid(poid));
		if (group == NULL)
			goto ecerr;
		EC_GROUP_set_asn1_flag(group, OPENSSL_EC_NAMED_CURVE);
		if (EC_KEY_set_group(eckey, group) == 0)
			goto ecerr;
		EC_GROUP_free(group);
		}
	else
		{
		ECerr(EC_F_ECKEY_TYPE2PARAM, EC_R_DECODE_ERROR);
		goto ecerr;
		}

	return eckey;

	ecerr:
	if (eckey)
		EC_KEY_free(eckey);
	return NULL;
	}

static int eckey_pub_decode(EVP_PKEY *pkey, X509_PUBKEY *pubkey)
	{
	const unsigned char *p = NULL;
	void *pval;
	int ptype, pklen;
	EC_KEY *eckey = NULL;
	X509_ALGOR *palg;

	if (!X509_PUBKEY_get0_param(NULL, &p, &pklen, &palg, pubkey))
		return 0;
	X509_ALGOR_get0(NULL, &ptype, &pval, palg);

	eckey = eckey_type2param(ptype, pval);

	if (!eckey)
		{
		ECerr(EC_F_ECKEY_PUB_DECODE, ERR_R_EC_LIB);
		return 0;
		}

	/* We have parameters now set public key */
	if (!o2i_ECPublicKey(&eckey, &p, pklen))
		{
		ECerr(EC_F_ECKEY_PUB_DECODE, EC_R_DECODE_ERROR);
		goto ecerr;
		}

	EVP_PKEY_assign_EC_KEY(pkey, eckey);
	return 1;

	ecerr:
	if (eckey)
		EC_KEY_free(eckey);
	return 0;
	}

static int eckey_pub_cmp(const EVP_PKEY *a, const EVP_PKEY *b)
	{
	int  r;
	const EC_GROUP *group = EC_KEY_get0_group(b->pkey.ec);
	const EC_POINT *pa = EC_KEY_get0_public_key(a->pkey.ec),
	               *pb = EC_KEY_get0_public_key(b->pkey.ec);
	r = EC_POINT_cmp(group, pa, pb, NULL);
	if (r == 0)
		return 1;
	if (r == 1)
		return 0;
	return -2;
	}

static int eckey_priv_decode(EVP_PKEY *pkey, PKCS8_PRIV_KEY_INFO *p8)
	{
	const unsigned char *p = NULL;
	void *pval;
	int ptype, pklen;
	EC_KEY *eckey = NULL;
	X509_ALGOR *palg;

	if (!PKCS8_pkey_get0(NULL, &p, &pklen, &palg, p8))
		return 0;
	X509_ALGOR_get0(NULL, &ptype, &pval, palg);

	eckey = eckey_type2param(ptype, pval);

	if (!eckey)
		goto ecliberr;

	/* We have parameters now set private key */
	if (!d2i_ECPrivateKey(&eckey, &p, pklen))
		{
		ECerr(EC_F_ECKEY_PRIV_DECODE, EC_R_DECODE_ERROR);
		goto ecerr;
		}

	/* calculate public key (if necessary) */
	if (EC_KEY_get0_public_key(eckey) == NULL)
		{
		const BIGNUM *priv_key;
		const EC_GROUP *group;
		EC_POINT *pub_key;
		/* the public key was not included in the SEC1 private
		 * key => calculate the public key */
		group   = EC_KEY_get0_group(eckey);
		pub_key = EC_POINT_new(group);
		if (pub_key == NULL)
			{
			ECerr(EC_F_ECKEY_PRIV_DECODE, ERR_R_EC_LIB);
			goto ecliberr;
			}
		if (!EC_POINT_copy(pub_key, EC_GROUP_get0_generator(group)))
			{
			EC_POINT_free(pub_key);
			ECerr(EC_F_ECKEY_PRIV_DECODE, ERR_R_EC_LIB);
			goto ecliberr;
			}
		priv_key = EC_KEY_get0_private_key(eckey);
		if (!EC_POINT_mul(group, pub_key, priv_key, NULL, NULL, NULL))
			{
			EC_POINT_free(pub_key);
			ECerr(EC_F_ECKEY_PRIV_DECODE, ERR_R_EC_LIB);
			goto ecliberr;
			}
		if (EC_KEY_set_public_key(eckey, pub_key) == 0)
			{
			EC_POINT_free(pub_key);
			ECerr(EC_F_ECKEY_PRIV_DECODE, ERR_R_EC_LIB);
			goto ecliberr;
			}
		EC_POINT_free(pub_key);
		}

	EVP_PKEY_assign_EC_KEY(pkey, eckey);
	return 1;

	ecliberr:
	ECerr(EC_F_ECKEY_PRIV_DECODE, ERR_R_EC_LIB);
	ecerr:
	if (eckey)
		EC_KEY_free(eckey);
	return 0;
	}

static int eckey_priv_encode(PKCS8_PRIV_KEY_INFO *p8, const EVP_PKEY *pkey)
{
	EC_KEY		*ec_key;
	unsigned char	*ep, *p;
	int 		eplen, ptype;
	void		*pval;
	unsigned int    tmp_flags, old_flags;

	ec_key = pkey->pkey.ec;

	if (!eckey_param2type(&ptype, &pval, ec_key))
		{
		ECerr(EC_F_ECKEY_PRIV_ENCODE, EC_R_DECODE_ERROR);
		return 0;
		}

	/* set the private key */

	/* do not include the parameters in the SEC1 private key
	 * see PKCS#11 12.11 */
	old_flags = EC_KEY_get_enc_flags(ec_key);
	tmp_flags = old_flags | EC_PKEY_NO_PARAMETERS;
	EC_KEY_set_enc_flags(ec_key, tmp_flags);
	eplen = i2d_ECPrivateKey(ec_key, NULL);
	if (!eplen)
	{
		EC_KEY_set_enc_flags(ec_key, old_flags);
		ECerr(EC_F_ECKEY_PRIV_ENCODE, ERR_R_EC_LIB);
		return 0;
	}
	ep = (unsigned char *) OPENSSL_malloc(eplen);
	if (!ep)
	{
		EC_KEY_set_enc_flags(ec_key, old_flags);
		ECerr(EC_F_ECKEY_PRIV_ENCODE, ERR_R_MALLOC_FAILURE);
		return 0;
	}
	p = ep;
	if (!i2d_ECPrivateKey(ec_key, &p))
	{
		EC_KEY_set_enc_flags(ec_key, old_flags);
		OPENSSL_free(ep);
		ECerr(EC_F_ECKEY_PRIV_ENCODE, ERR_R_EC_LIB);
	}
	/* restore old encoding flags */
	EC_KEY_set_enc_flags(ec_key, old_flags);

	if (!PKCS8_pkey_set0(p8, OBJ_nid2obj(NID_X9_62_id_ecPublicKey), 0,
				ptype, pval, ep, eplen))
		return 0;

	return 1;
}

static int int_ec_size(const EVP_PKEY *pkey)
	{
	return ECDSA_size(pkey->pkey.ec);
	}

static int ec_bits(const EVP_PKEY *pkey)
	{
	BIGNUM *order = BN_new();
	const EC_GROUP *group;
	int ret;

	if (!order)
		{
		ERR_clear_error();
		return 0;
		}
	group = EC_KEY_get0_group(pkey->pkey.ec);
	if (!EC_GROUP_get_order(group, order, NULL))
		{
		ERR_clear_error();
		return 0;
		}

	ret = BN_num_bits(order);
	BN_free(order);
	return ret;
	}

static int ec_missing_parameters(const EVP_PKEY *pkey)
	{
	if (EC_KEY_get0_group(pkey->pkey.ec) == NULL)
		return 1;
	return 0;
	}

int ec_copy_parameters(EVP_PKEY *to, const EVP_PKEY *from)
	{
	EC_GROUP *group = EC_GROUP_dup(EC_KEY_get0_group(from->pkey.ec));
	if (group == NULL)
		return 0;
	if (EC_KEY_set_group(to->pkey.ec, group) == 0)
		return 0;
	EC_GROUP_free(group);
	return 1;
	}

int ec_cmp_parameters(const EVP_PKEY *a, const EVP_PKEY *b)
	{
	const EC_GROUP *group_a = EC_KEY_get0_group(a->pkey.ec),
	               *group_b = EC_KEY_get0_group(b->pkey.ec);
	if (EC_GROUP_cmp(group_a, group_b, NULL))
		return 0;
	else
		return 1;
	}

static void int_ec_free(EVP_PKEY *pkey)
	{
	EC_KEY_free(pkey->pkey.ec);
	}

static int do_EC_KEY_print(BIO *bp, const EC_KEY *x, int off, int ktype)
	{
	unsigned char *buffer=NULL;
	const char *ecstr;
	size_t	buf_len=0, i;
	int     ret=0, reason=ERR_R_BIO_LIB;
	BIGNUM  *pub_key=NULL, *order=NULL;
	BN_CTX  *ctx=NULL;
	const EC_GROUP *group;
	const EC_POINT *public_key;
	const BIGNUM *priv_key;
 
	if (x == NULL || (group = EC_KEY_get0_group(x)) == NULL)
		{
		reason = ERR_R_PASSED_NULL_PARAMETER;
		goto err;
		}

	ctx = BN_CTX_new();
	if (ctx == NULL)
		{
		reason = ERR_R_MALLOC_FAILURE;
		goto err;
		}

	if (ktype > 0)
		{
		public_key = EC_KEY_get0_public_key(x);
		if ((pub_key = EC_POINT_point2bn(group, public_key,
			EC_KEY_get_conv_form(x), NULL, ctx)) == NULL)
			{
			reason = ERR_R_EC_LIB;
			goto err;
			}
		if (pub_key)
			buf_len = (size_t)BN_num_bytes(pub_key);
		}

	if (ktype == 2)
		{
		priv_key = EC_KEY_get0_private_key(x);
		if (priv_key && (i = (size_t)BN_num_bytes(priv_key)) > buf_len)
			buf_len = i;
		}
	else
		priv_key = NULL;

	if (ktype > 0)
		{
		buf_len += 10;
		if ((buffer = OPENSSL_malloc(buf_len)) == NULL)
			{
			reason = ERR_R_MALLOC_FAILURE;
			goto err;
			}
		}
	if (ktype == 2)
		ecstr = "Private-Key";
	else if (ktype == 1)
		ecstr = "Public-Key";
	else
		ecstr = "ECDSA-Parameters";

	if (!BIO_indent(bp, off, 128))
		goto err;
	if ((order = BN_new()) == NULL)
		goto err;
	if (!EC_GROUP_get_order(group, order, NULL))
		goto err;
	if (BIO_printf(bp, "%s: (%d bit)\n", ecstr,
		BN_num_bits(order)) <= 0) goto err;
  
	if ((priv_key != NULL) && !ASN1_bn_print(bp, "priv:", priv_key, 
		buffer, off))
		goto err;
	if ((pub_key != NULL) && !ASN1_bn_print(bp, "pub: ", pub_key,
		buffer, off))
		goto err;
	if (!ECPKParameters_print(bp, group, off))
		goto err;
	ret=1;
err:
	if (!ret)
 		ECerr(EC_F_EC_KEY_PRINT, reason);
	if (pub_key) 
		BN_free(pub_key);
	if (order)
		BN_free(order);
	if (ctx)
		BN_CTX_free(ctx);
	if (buffer != NULL)
		OPENSSL_free(buffer);
	return(ret);
	}

static int eckey_param_decode(EVP_PKEY *pkey,
					const unsigned char **pder, int derlen)
	{
	EC_KEY *eckey;
	if (!(eckey = d2i_ECParameters(NULL, pder, derlen)))
		{
		ECerr(EC_F_ECKEY_PARAM_DECODE, ERR_R_EC_LIB);
		return 0;
		}
	EVP_PKEY_assign_EC_KEY(pkey, eckey);
	return 1;
	}

static int eckey_param_encode(const EVP_PKEY *pkey, unsigned char **pder)
	{
	return i2d_ECParameters(pkey->pkey.ec, pder);
	}

static int eckey_param_print(BIO *bp, const EVP_PKEY *pkey, int indent,
							ASN1_PCTX *ctx)
	{
	return do_EC_KEY_print(bp, pkey->pkey.ec, indent, 0);
	}

static int eckey_pub_print(BIO *bp, const EVP_PKEY *pkey, int indent,
							ASN1_PCTX *ctx)
	{
	return do_EC_KEY_print(bp, pkey->pkey.ec, indent, 1);
	}


static int eckey_priv_print(BIO *bp, const EVP_PKEY *pkey, int indent,
							ASN1_PCTX *ctx)
	{
	return do_EC_KEY_print(bp, pkey->pkey.ec, indent, 2);
	}

static int old_ec_priv_decode(EVP_PKEY *pkey,
					const unsigned char **pder, int derlen)
	{
	EC_KEY *ec;
	if (!(ec = d2i_ECPrivateKey (NULL, pder, derlen)))
		{
		ECerr(EC_F_ECKEY_PRIV_DECODE, EC_R_DECODE_ERROR);
		return 0;
		}
	EVP_PKEY_assign_EC_KEY(pkey, ec);
	return 1;
	}

static int old_ec_priv_encode(const EVP_PKEY *pkey, unsigned char **pder)
	{
	return i2d_ECPrivateKey(pkey->pkey.ec, pder);
	}

EVP_PKEY_ASN1_METHOD eckey_asn1_meth = 
	{
	EVP_PKEY_EC,
	EVP_PKEY_EC,
	0,
	"EC",
	"OpenSSL EC algorithm",

	eckey_pub_decode,
	eckey_pub_encode,
	eckey_pub_cmp,
	eckey_pub_print,

	eckey_priv_decode,
	eckey_priv_encode,
	eckey_priv_print,

	int_ec_size,
	ec_bits,

	eckey_param_decode,
	eckey_param_encode,
	ec_missing_parameters,
	ec_copy_parameters,
	ec_cmp_parameters,
	eckey_param_print,

	int_ec_free,
	0,
	old_ec_priv_decode,
	old_ec_priv_encode
	};