crypto/ec/ec_ameth.c

/* $OpenBSD: ec_ameth.c,v 1.25 2018/08/24 20:22:15 tb Exp $ */
/* Written by Dr Stephen N Henson (steve@openssl.org) 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 <openssl/opensslconf.h>

#include <openssl/bn.h>
#include <openssl/ec.h>
#include <openssl/err.h>
#include <openssl/x509.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) {
		ECerror(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);
			ECerror(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)) {
		ECerror(ERR_R_EC_LIB);
		return 0;
	}
	penclen = i2o_ECPublicKey(ec_key, NULL);
	if (penclen <= 0)
		goto err;
	penc = 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);
	free(penc);
	return 0;
}

static EC_KEY *
eckey_type2param(int ptype, const void *pval)
{
	EC_KEY *eckey = NULL;

	if (ptype == V_ASN1_SEQUENCE) {
		const ASN1_STRING *pstr = pval;
		const unsigned char *pm = NULL;
		int pmlen;

		pm = pstr->data;
		pmlen = pstr->length;
		if (!(eckey = d2i_ECParameters(NULL, &pm, pmlen))) {
			ECerror(EC_R_DECODE_ERROR);
			goto ecerr;
		}
	} else if (ptype == V_ASN1_OBJECT) {
		const 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) {
			ECerror(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 {
		ECerror(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;
	const 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) {
		ECerror(ERR_R_EC_LIB);
		return 0;
	}
	/* We have parameters now set public key */
	if (!o2i_ECPublicKey(&eckey, &p, pklen)) {
		ECerror(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, const PKCS8_PRIV_KEY_INFO * p8)
{
	const unsigned char *p = NULL;
	const void *pval;
	int ptype, pklen;
	EC_KEY *eckey = NULL;
	const 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)) {
		ECerror(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) {
			ECerror(ERR_R_EC_LIB);
			goto ecliberr;
		}
		if (!EC_POINT_copy(pub_key, EC_GROUP_get0_generator(group))) {
			EC_POINT_free(pub_key);
			ECerror(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);
			ECerror(ERR_R_EC_LIB);
			goto ecliberr;
		}
		if (EC_KEY_set_public_key(eckey, pub_key) == 0) {
			EC_POINT_free(pub_key);
			ECerror(ERR_R_EC_LIB);
			goto ecliberr;
		}
		EC_POINT_free(pub_key);
	}
	EVP_PKEY_assign_EC_KEY(pkey, eckey);
	return 1;

 ecliberr:
	ECerror(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)) {
		ECerror(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);
		ECerror(ERR_R_EC_LIB);
		return 0;
	}
	ep = malloc(eplen);
	if (!ep) {
		EC_KEY_set_enc_flags(ec_key, old_flags);
		ECerror(ERR_R_MALLOC_FAILURE);
		return 0;
	}
	p = ep;
	if (!i2d_ECPrivateKey(ec_key, &p)) {
		EC_KEY_set_enc_flags(ec_key, old_flags);
		free(ep);
		ECerror(ERR_R_EC_LIB);
		return 0;
	}
	/* 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)) {
		BN_free(order);
		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;
}

static int
ec_copy_parameters(EVP_PKEY * to, const EVP_PKEY * from)
{
	return EC_KEY_set_group(to->pkey.ec, EC_KEY_get0_group(from->pkey.ec));
}

static 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 (public_key != NULL) {
			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 = 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)
		ECerror(reason);
	BN_free(pub_key);
	BN_free(order);
	BN_CTX_free(ctx);
	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))) {
		ECerror(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))) {
		ECerror(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);
}

static int
ec_pkey_ctrl(EVP_PKEY * pkey, int op, long arg1, void *arg2)
{
	switch (op) {
	case ASN1_PKEY_CTRL_PKCS7_SIGN:
		if (arg1 == 0) {
			int snid, hnid;
			X509_ALGOR *alg1, *alg2;
			PKCS7_SIGNER_INFO_get0_algs(arg2, NULL, &alg1, &alg2);
			if (alg1 == NULL || alg1->algorithm == NULL)
				return -1;
			hnid = OBJ_obj2nid(alg1->algorithm);
			if (hnid == NID_undef)
				return -1;
			if (!OBJ_find_sigid_by_algs(&snid, hnid, EVP_PKEY_id(pkey)))
				return -1;
			X509_ALGOR_set0(alg2, OBJ_nid2obj(snid), V_ASN1_UNDEF, 0);
		}
		return 1;

	case ASN1_PKEY_CTRL_DEFAULT_MD_NID:
		*(int *) arg2 = NID_sha1;
		return 2;

	default:
		return -2;

	}

}

const EVP_PKEY_ASN1_METHOD eckey_asn1_meth = {
	.pkey_id = EVP_PKEY_EC,
	.pkey_base_id = EVP_PKEY_EC,

	.pem_str = "EC",
	.info = "OpenSSL EC algorithm",

	.pub_decode = eckey_pub_decode,
	.pub_encode = eckey_pub_encode,
	.pub_cmp = eckey_pub_cmp,
	.pub_print = eckey_pub_print,

	.priv_decode = eckey_priv_decode,
	.priv_encode = eckey_priv_encode,
	.priv_print = eckey_priv_print,

	.pkey_size = int_ec_size,
	.pkey_bits = ec_bits,

	.param_decode = eckey_param_decode,
	.param_encode = eckey_param_encode,
	.param_missing = ec_missing_parameters,
	.param_copy = ec_copy_parameters,
	.param_cmp = ec_cmp_parameters,
	.param_print = eckey_param_print,

	.pkey_free = int_ec_free,
	.pkey_ctrl = ec_pkey_ctrl,
	.old_priv_decode = old_ec_priv_decode,
	.old_priv_encode = old_ec_priv_encode
};