/* $OpenBSD: ec_ameth.c,v 1.33 2022/06/27 12:36:05 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/cms.h>
#include <openssl/ec.h>
#include <openssl/err.h>
#include <openssl/x509.h>

#include "asn1_locl.h"
#include "ec_lcl.h"
#include "evp_locl.h"

#ifndef OPENSSL_NO_CMS
static int ecdh_cms_decrypt(CMS_RecipientInfo *ri);
static int ecdh_cms_encrypt(CMS_RecipientInfo *ri);
#endif

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_GROUP *group = NULL;
        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;

                /*
                 * 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;
        } else {
                ECerror(EC_R_DECODE_ERROR);
                goto ecerr;
        }

        EC_GROUP_free(group);
        return eckey;

 ecerr:
        EC_KEY_free(eckey);
        EC_GROUP_free(group);
        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_security_bits(const EVP_PKEY *pkey)
{
        int ecbits = ec_bits(pkey);

        if (ecbits >= 512)
                return 256;
        if (ecbits >= 384)
                return 192;
        if (ecbits >= 256)
                return 128;
        if (ecbits >= 224)
                return 112;
        if (ecbits >= 160)
                return 80;

        return ecbits / 2;
}

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;

#ifndef OPENSSL_NO_CMS
        case ASN1_PKEY_CTRL_CMS_SIGN:
                if (arg1 == 0) {
                        X509_ALGOR *alg1, *alg2;
                        int snid, hnid;

                        CMS_SignerInfo_get0_algs(arg2, NULL, 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_CMS_ENVELOPE:
                if (arg1 == 0)
                        return ecdh_cms_encrypt(arg2);
                else if (arg1 == 1)
                        return ecdh_cms_decrypt(arg2);
                return -2;

        case ASN1_PKEY_CTRL_CMS_RI_TYPE:
                *(int *)arg2 = CMS_RECIPINFO_AGREE;
                return 1;
#endif

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

        default:
                return -2;

        }

}

static int
ec_pkey_check(const EVP_PKEY *pkey)
{
        EC_KEY *eckey = pkey->pkey.ec;

        if (eckey->priv_key == NULL) {
                ECerror(EC_R_MISSING_PRIVATE_KEY);
                return 0;
        }

        return EC_KEY_check_key(eckey);
}

static int
ec_pkey_public_check(const EVP_PKEY *pkey)
{
        EC_KEY *eckey = pkey->pkey.ec;

        /* This also checks the private key, but oh, well... */
        return EC_KEY_check_key(eckey);
}

static int
ec_pkey_param_check(const EVP_PKEY *pkey)
{
        EC_KEY *eckey = pkey->pkey.ec;

        if (eckey->group == NULL) {
                ECerror(EC_R_MISSING_PARAMETERS);
                return 0;
        }

        return EC_GROUP_check(eckey->group, NULL);
}

#ifndef OPENSSL_NO_CMS

static int
ecdh_cms_set_peerkey(EVP_PKEY_CTX *pctx, X509_ALGOR *alg,
    ASN1_BIT_STRING *pubkey)
{
        const ASN1_OBJECT *aoid;
        int atype;
        const void *aval;
        int rv = 0;
        EVP_PKEY *pkpeer = NULL;
        EC_KEY *ecpeer = NULL;
        const unsigned char *p;
        int plen;

        X509_ALGOR_get0(&aoid, &atype, &aval, alg);
        if (OBJ_obj2nid(aoid) != NID_X9_62_id_ecPublicKey)
                goto err;

        /* If absent parameters get group from main key */
        if (atype == V_ASN1_UNDEF || atype == V_ASN1_NULL) {
                const EC_GROUP *grp;
                EVP_PKEY *pk;

                pk = EVP_PKEY_CTX_get0_pkey(pctx);
                if (!pk)
                        goto err;
                grp = EC_KEY_get0_group(pk->pkey.ec);
                ecpeer = EC_KEY_new();
                if (ecpeer == NULL)
                        goto err;
                if (!EC_KEY_set_group(ecpeer, grp))
                        goto err;
        } else {
                ecpeer = eckey_type2param(atype, aval);
                if (!ecpeer)
                        goto err;
        }

        /* We have parameters now set public key */
        plen = ASN1_STRING_length(pubkey);
        p = ASN1_STRING_get0_data(pubkey);
        if (!p || !plen)
                goto err;
        if (!o2i_ECPublicKey(&ecpeer, &p, plen))
                goto err;
        pkpeer = EVP_PKEY_new();
        if (pkpeer == NULL)
                goto err;
        EVP_PKEY_set1_EC_KEY(pkpeer, ecpeer);
        if (EVP_PKEY_derive_set_peer(pctx, pkpeer) > 0)
                rv = 1;
 err:
        EC_KEY_free(ecpeer);
        EVP_PKEY_free(pkpeer);
        return rv;
}

/* Set KDF parameters based on KDF NID */
static int
ecdh_cms_set_kdf_param(EVP_PKEY_CTX *pctx, int eckdf_nid)
{
        int kdf_nid, kdfmd_nid, cofactor;
        const EVP_MD *kdf_md;

        if (eckdf_nid == NID_undef)
                return 0;

        /* Lookup KDF type, cofactor mode and digest */
        if (!OBJ_find_sigid_algs(eckdf_nid, &kdfmd_nid, &kdf_nid))
                return 0;

        if (kdf_nid == NID_dh_std_kdf)
                cofactor = 0;
        else if (kdf_nid == NID_dh_cofactor_kdf)
                cofactor = 1;
        else
                return 0;

        if (EVP_PKEY_CTX_set_ecdh_cofactor_mode(pctx, cofactor) <= 0)
                return 0;

        if (EVP_PKEY_CTX_set_ecdh_kdf_type(pctx, EVP_PKEY_ECDH_KDF_X9_63) <= 0)
                return 0;

        kdf_md = EVP_get_digestbynid(kdfmd_nid);
        if (!kdf_md)
                return 0;

        if (EVP_PKEY_CTX_set_ecdh_kdf_md(pctx, kdf_md) <= 0)
                return 0;

        return 1;
}

static int
ecdh_cms_set_shared_info(EVP_PKEY_CTX *pctx, CMS_RecipientInfo *ri)
{
        X509_ALGOR *alg, *kekalg = NULL;
        ASN1_OCTET_STRING *ukm;
        const unsigned char *p;
        unsigned char *der = NULL;
        int plen, keylen;
        const EVP_CIPHER *kekcipher;
        EVP_CIPHER_CTX *kekctx;
        int rv = 0;

        if (!CMS_RecipientInfo_kari_get0_alg(ri, &alg, &ukm))
                return 0;

        if (!ecdh_cms_set_kdf_param(pctx, OBJ_obj2nid(alg->algorithm))) {
                ECerror(EC_R_KDF_PARAMETER_ERROR);
                return 0;
        }

        if (alg->parameter->type != V_ASN1_SEQUENCE)
                return 0;

        p = alg->parameter->value.sequence->data;
        plen = alg->parameter->value.sequence->length;
        kekalg = d2i_X509_ALGOR(NULL, &p, plen);
        if (!kekalg)
                goto err;
        kekctx = CMS_RecipientInfo_kari_get0_ctx(ri);
        if (!kekctx)
                goto err;
        kekcipher = EVP_get_cipherbyobj(kekalg->algorithm);
        if (!kekcipher || EVP_CIPHER_mode(kekcipher) != EVP_CIPH_WRAP_MODE)
                goto err;
        if (!EVP_EncryptInit_ex(kekctx, kekcipher, NULL, NULL, NULL))
                goto err;
        if (EVP_CIPHER_asn1_to_param(kekctx, kekalg->parameter) <= 0)
                goto err;

        keylen = EVP_CIPHER_CTX_key_length(kekctx);
        if (EVP_PKEY_CTX_set_ecdh_kdf_outlen(pctx, keylen) <= 0)
                goto err;

        plen = CMS_SharedInfo_encode(&der, kekalg, ukm, keylen);
        if (!plen)
                goto err;

        if (EVP_PKEY_CTX_set0_ecdh_kdf_ukm(pctx, der, plen) <= 0)
                goto err;
        der = NULL;

        rv = 1;
 err:
        X509_ALGOR_free(kekalg);
        free(der);
        return rv;
}

static int
ecdh_cms_decrypt(CMS_RecipientInfo *ri)
{
        EVP_PKEY_CTX *pctx;

        pctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
        if (!pctx)
                return 0;

        /* See if we need to set peer key */
        if (!EVP_PKEY_CTX_get0_peerkey(pctx)) {
                X509_ALGOR *alg;
                ASN1_BIT_STRING *pubkey;

                if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &alg, &pubkey,
                    NULL, NULL, NULL))
                        return 0;
                if (!alg || !pubkey)
                        return 0;
                if (!ecdh_cms_set_peerkey(pctx, alg, pubkey)) {
                        ECerror(EC_R_PEER_KEY_ERROR);
                        return 0;
                }
        }

        /* Set ECDH derivation parameters and initialise unwrap context */
        if (!ecdh_cms_set_shared_info(pctx, ri)) {
                ECerror(EC_R_SHARED_INFO_ERROR);
                return 0;
        }

        return 1;
}

static int
ecdh_cms_encrypt(CMS_RecipientInfo *ri)
{
        EVP_PKEY_CTX *pctx;
        EVP_PKEY *pkey;
        EVP_CIPHER_CTX *ctx;
        int keylen;
        X509_ALGOR *talg, *wrap_alg = NULL;
        const ASN1_OBJECT *aoid;
        ASN1_BIT_STRING *pubkey;
        ASN1_STRING *wrap_str;
        ASN1_OCTET_STRING *ukm;
        unsigned char *penc = NULL;
        int penclen;
        int ecdh_nid, kdf_type, kdf_nid, wrap_nid;
        const EVP_MD *kdf_md;
        int rv = 0;

        pctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
        if (!pctx)
                return 0;
        /* Get ephemeral key */
        pkey = EVP_PKEY_CTX_get0_pkey(pctx);
        if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &talg, &pubkey,
            NULL, NULL, NULL))
                goto err;
        X509_ALGOR_get0(&aoid, NULL, NULL, talg);

        /* Is everything uninitialised? */
        if (aoid == OBJ_nid2obj(NID_undef)) {
                EC_KEY *eckey = pkey->pkey.ec;
                unsigned char *p;

                /* Set the key */
                penclen = i2o_ECPublicKey(eckey, NULL);
                if (penclen <= 0)
                        goto err;
                penc = malloc(penclen);
                if (penc == NULL)
                        goto err;
                p = penc;
                penclen = i2o_ECPublicKey(eckey, &p);
                if (penclen <= 0)
                        goto err;
                ASN1_STRING_set0(pubkey, penc, penclen);
                if (!asn1_abs_set_unused_bits(pubkey, 0))
                        goto err;
                penc = NULL;

                X509_ALGOR_set0(talg, OBJ_nid2obj(NID_X9_62_id_ecPublicKey),
                    V_ASN1_UNDEF, NULL);
        }

        /* See if custom parameters set */
        kdf_type = EVP_PKEY_CTX_get_ecdh_kdf_type(pctx);
        if (kdf_type <= 0)
                goto err;
        if (!EVP_PKEY_CTX_get_ecdh_kdf_md(pctx, &kdf_md))
                goto err;
        ecdh_nid = EVP_PKEY_CTX_get_ecdh_cofactor_mode(pctx);
        if (ecdh_nid < 0)
                goto err;
        else if (ecdh_nid == 0)
                ecdh_nid = NID_dh_std_kdf;
        else if (ecdh_nid == 1)
                ecdh_nid = NID_dh_cofactor_kdf;

        if (kdf_type == EVP_PKEY_ECDH_KDF_NONE) {
                kdf_type = EVP_PKEY_ECDH_KDF_X9_63;
                if (EVP_PKEY_CTX_set_ecdh_kdf_type(pctx, kdf_type) <= 0)
                        goto err;
        } else {
                /* Unknown KDF */
                goto err;
        }
        if (kdf_md == NULL) {
                /* Fixme later for better MD */
                kdf_md = EVP_sha1();
                if (EVP_PKEY_CTX_set_ecdh_kdf_md(pctx, kdf_md) <= 0)
                        goto err;
        }

        if (!CMS_RecipientInfo_kari_get0_alg(ri, &talg, &ukm))
                goto err;

        /* Lookup NID for KDF+cofactor+digest */
        if (!OBJ_find_sigid_by_algs(&kdf_nid, EVP_MD_type(kdf_md), ecdh_nid))
                goto err;

        /* Get wrap NID */
        ctx = CMS_RecipientInfo_kari_get0_ctx(ri);
        wrap_nid = EVP_CIPHER_CTX_type(ctx);
        keylen = EVP_CIPHER_CTX_key_length(ctx);

        /* Package wrap algorithm in an AlgorithmIdentifier */

        wrap_alg = X509_ALGOR_new();
        if (wrap_alg == NULL)
                goto err;
        wrap_alg->algorithm = OBJ_nid2obj(wrap_nid);
        wrap_alg->parameter = ASN1_TYPE_new();
        if (wrap_alg->parameter == NULL)
                goto err;
        if (EVP_CIPHER_param_to_asn1(ctx, wrap_alg->parameter) <= 0)
                goto err;
        if (ASN1_TYPE_get(wrap_alg->parameter) == NID_undef) {
                ASN1_TYPE_free(wrap_alg->parameter);
                wrap_alg->parameter = NULL;
        }

        if (EVP_PKEY_CTX_set_ecdh_kdf_outlen(pctx, keylen) <= 0)
                goto err;

        penclen = CMS_SharedInfo_encode(&penc, wrap_alg, ukm, keylen);
        if (!penclen)
                goto err;

        if (EVP_PKEY_CTX_set0_ecdh_kdf_ukm(pctx, penc, penclen) <= 0)
                goto err;
        penc = NULL;

        /*
         * Now need to wrap encoding of wrap AlgorithmIdentifier into parameter
         * of another AlgorithmIdentifier.
         */
        penclen = i2d_X509_ALGOR(wrap_alg, &penc);
        if (!penc || !penclen)
                goto err;
        wrap_str = ASN1_STRING_new();
        if (wrap_str == NULL)
                goto err;
        ASN1_STRING_set0(wrap_str, penc, penclen);
        penc = NULL;
        X509_ALGOR_set0(talg, OBJ_nid2obj(kdf_nid), V_ASN1_SEQUENCE, wrap_str);

        rv = 1;

 err:
        free(penc);
        X509_ALGOR_free(wrap_alg);
        return rv;
}

#endif

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,
        .pkey_security_bits = ec_security_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,

        .pkey_check = ec_pkey_check,
        .pkey_public_check = ec_pkey_public_check,
        .pkey_param_check = ec_pkey_param_check,
};