/* $OpenBSD: ec_ameth.c,v 1.74 2025/05/10 05:54:38 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 <stddef.h>
#include <stdlib.h>

#include <openssl/opensslconf.h>

#include <openssl/asn1.h>
#include <openssl/bio.h>
#include <openssl/bn.h>
#include <openssl/cms.h>
#include <openssl/ec.h>
#include <openssl/evp.h>
#include <openssl/pkcs7.h>
#include <openssl/objects.h>
#include <openssl/x509.h>

#include "asn1_local.h"
#include "bn_local.h"
#include "err_local.h"
#include "evp_local.h"
#include "x509_local.h"

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

static void
eckey_param_free(int ptype, void *pval)
{
        if (pval == NULL)
                return;
        if (ptype == V_ASN1_OBJECT)
                ASN1_OBJECT_free(pval);         /* XXX - really necessary? */
        else
                ASN1_STRING_free(pval);
}

static int
eckey_get_curve_name(const EC_KEY *eckey, int *nid)
{
        const EC_GROUP *group;

        *nid = NID_undef;

        if ((group = EC_KEY_get0_group(eckey)) == NULL) {
                ECerror(EC_R_MISSING_PARAMETERS);
                return 0;
        }
        if ((EC_GROUP_get_asn1_flag(group) & OPENSSL_EC_NAMED_CURVE) != 0)
                *nid = EC_GROUP_get_curve_name(group);

        return 1;
}

static int
eckey_to_explicit_params(EC_KEY *eckey, void **out_val)
{
        ASN1_STRING *astr = NULL;
        unsigned char *params = NULL;
        int params_len = 0;
        int ret = 0;

        *out_val = NULL;

        if ((params_len = i2d_ECParameters(eckey, &params)) <= 0) {
                ECerror(ERR_R_EC_LIB);
                params_len = 0;
                goto err;
        }

        if ((astr = ASN1_STRING_new()) == NULL)
                goto err;
        ASN1_STRING_set0(astr, params, params_len);
        params = NULL;
        params_len = 0;

        *out_val = astr;
        astr = NULL;

        ret = 1;

 err:
        freezero(params, params_len);
        ASN1_STRING_free(astr);

        return ret;
}

static int
eckey_from_explicit_params(const ASN1_STRING *astr, EC_KEY **out_eckey)
{
        const unsigned char *params = astr->data;
        int params_len = astr->length;

        EC_KEY_free(*out_eckey);
        if ((*out_eckey = d2i_ECParameters(NULL, &params, params_len)) == NULL) {
                ECerror(EC_R_DECODE_ERROR);
                return 0;
        }

        return 1;
}

static int
eckey_to_object(const EC_KEY *eckey, void **out_val)
{
        int nid = NID_undef;

        *out_val = NULL;

        if (!eckey_get_curve_name(eckey, &nid))
                return 0;
        if ((*out_val = OBJ_nid2obj(nid)) == NULL)
                return 0;

        return 1;
}

static int
eckey_from_object(const ASN1_OBJECT *aobj, EC_KEY **out_eckey)
{
        int nid;

        EC_KEY_free(*out_eckey);
        *out_eckey = NULL;

        if ((nid = OBJ_obj2nid(aobj)) == NID_undef)
                return 0;
        if ((*out_eckey = EC_KEY_new_by_curve_name(nid)) == NULL)
                return 0;

        return 1;
}

static int
eckey_to_params(EC_KEY *eckey, int *out_type, void **out_val)
{
        int nid;

        *out_type = NID_undef;
        *out_val = NULL;

        if (!eckey_get_curve_name(eckey, &nid))
                return 0;

        if (nid == NID_undef) {
                *out_type = V_ASN1_SEQUENCE;
                return eckey_to_explicit_params(eckey, out_val);
        } else {
                *out_type = V_ASN1_OBJECT;
                return eckey_to_object(eckey, out_val);
        }
}

static int
eckey_from_params(int ptype, const void *pval, EC_KEY **out_eckey)
{
        EC_KEY_free(*out_eckey);
        *out_eckey = NULL;

        if (ptype == V_ASN1_SEQUENCE)
                return eckey_from_explicit_params(pval, out_eckey);
        if (ptype == V_ASN1_OBJECT)
                return eckey_from_object(pval, out_eckey);

        ECerror(EC_R_DECODE_ERROR);
        return 0;
}

static int
eckey_pub_encode(X509_PUBKEY *pk, const EVP_PKEY *pkey)
{
        EC_KEY *eckey = pkey->pkey.ec;
        int ptype = V_ASN1_UNDEF;
        void *pval = NULL;
        ASN1_OBJECT *aobj;
        unsigned char *key = NULL;
        int key_len = 0;
        int ret = 0;

        if (!eckey_to_params(eckey, &ptype, &pval)) {
                ECerror(ERR_R_EC_LIB);
                goto err;
        }
        if ((key_len = i2o_ECPublicKey(eckey, &key)) <= 0) {
                key_len = 0;
                goto err;
        }
        if ((aobj = OBJ_nid2obj(EVP_PKEY_EC)) == NULL)
                goto err;
        if (!X509_PUBKEY_set0_param(pk, aobj, ptype, pval, key, key_len))
                goto err;
        pval = NULL;
        key = NULL;
        key_len = 0;

        ret = 1;

 err:
        eckey_param_free(ptype, pval);
        freezero(key, key_len);

        return ret;
}

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;
        int ret = 0;

        if (!X509_PUBKEY_get0_param(NULL, &p, &pklen, &palg, pubkey))
                goto err;

        X509_ALGOR_get0(NULL, &ptype, &pval, palg);
        if (!eckey_from_params(ptype, pval, &eckey))
                goto err;

        if (!o2i_ECPublicKey(&eckey, &p, pklen)) {
                ECerror(EC_R_DECODE_ERROR);
                goto err;
        }
        if (!EVP_PKEY_assign_EC_KEY(pkey, eckey))
                goto err;
        eckey = NULL;

        ret = 1;

 err:
        EC_KEY_free(eckey);

        return ret;
}

static int
eckey_pub_cmp(const EVP_PKEY *a, const EVP_PKEY *b)
{
        const EC_GROUP *group = EC_KEY_get0_group(b->pkey.ec);
        const EC_POINT *pa = EC_KEY_get0_public_key(a->pkey.ec);
        const EC_POINT *pb = EC_KEY_get0_public_key(b->pkey.ec);
        int r;

        r = EC_POINT_cmp(group, pa, pb, NULL);
        if (r == 0)
                return 1;
        if (r == 1)
                return 0;
        return -2;
}

int
eckey_compute_pubkey(EC_KEY *eckey)
{
        const BIGNUM *priv_key;
        const EC_GROUP *group;
        EC_POINT *pub_key = NULL;
        int ret = 0;

        if ((priv_key = EC_KEY_get0_private_key(eckey)) == NULL)
                goto err;
        if ((group = EC_KEY_get0_group(eckey)) == NULL)
                goto err;
        if ((pub_key = EC_POINT_new(group)) == NULL)
                goto err;
        if (!EC_POINT_mul(group, pub_key, priv_key, NULL, NULL, NULL))
                goto err;
        if (!EC_KEY_set_public_key(eckey, pub_key))
                goto err;

        ret = 1;

 err:
        EC_POINT_free(pub_key);

        return ret;
}

static int
eckey_priv_decode(EVP_PKEY *pkey, const PKCS8_PRIV_KEY_INFO *p8)
{
        const unsigned char *priv = NULL;
        int priv_len;
        const void *pval;
        int ptype;
        EC_KEY *eckey = NULL;
        const X509_ALGOR *palg;
        int ret = 0;

        if (!PKCS8_pkey_get0(NULL, &priv, &priv_len, &palg, p8))
                goto err;

        X509_ALGOR_get0(NULL, &ptype, &pval, palg);
        if (!eckey_from_params(ptype, pval, &eckey))
                goto err;

        /* Decode private key into eckey. */
        if (d2i_ECPrivateKey(&eckey, &priv, priv_len) == NULL) {
                ECerror(EC_R_DECODE_ERROR);
                goto err;
        }
        /* If public key was missing from SEC1 key, compute it. */
        if (EC_KEY_get0_public_key(eckey) == NULL) {
                if (!eckey_compute_pubkey(eckey))
                        goto err;
        }

        if (!EVP_PKEY_assign_EC_KEY(pkey, eckey))
                goto err;
        eckey = NULL;

        ret = 1;

 err:
        EC_KEY_free(eckey);

        return ret;
}

static int
eckey_priv_encode(PKCS8_PRIV_KEY_INFO *p8, const EVP_PKEY *pkey)
{
        EC_KEY *eckey = pkey->pkey.ec;
        void *pval = NULL;
        int ptype = V_ASN1_UNDEF;
        ASN1_OBJECT *aobj;
        unsigned char *key = NULL;
        int key_len = 0;
        unsigned int flags;
        int ret = 0;

        flags = EC_KEY_get_enc_flags(eckey);

        if (!eckey_to_params(eckey, &ptype, &pval)) {
                ECerror(EC_R_DECODE_ERROR);
                goto err;
        }

        /* PKCS#11 12.11: don't include parameters in the SEC1 private key. */
        EC_KEY_set_enc_flags(eckey, flags | EC_PKEY_NO_PARAMETERS);

        if ((key_len = i2d_ECPrivateKey(eckey, &key)) <= 0) {
                ECerror(ERR_R_EC_LIB);
                key_len = 0;
                goto err;
        }
        if ((aobj = OBJ_nid2obj(NID_X9_62_id_ecPublicKey)) == NULL)
                goto err;
        if (!PKCS8_pkey_set0(p8, aobj, 0, ptype, pval, key, key_len))
                goto err;
        pval = NULL;
        key = NULL;
        key_len = 0;

        ret = 1;

 err:
        eckey_param_free(ptype, pval);
        freezero(key, key_len);

        EC_KEY_set_enc_flags(eckey, flags);

        return ret;
}

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

static int
ec_bits(const EVP_PKEY *pkey)
{
        const EC_GROUP *group;

        if ((group = EC_KEY_get0_group(pkey->pkey.ec)) == NULL)
                return 0;

        return EC_GROUP_order_bits(group);
}

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);
        const EC_GROUP *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
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)
{
        const char *ecstr;
        int ret = 0, reason = ERR_R_BIO_LIB;
        BIGNUM *pub_key = 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 (ktype == 2) {
                priv_key = EC_KEY_get0_private_key(x);
        } else
                priv_key = NULL;

        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 (BIO_printf(bp, "%s: (%d bit)\n", ecstr,
            EC_GROUP_order_bits(group)) <= 0)
                goto err;

        if (!bn_printf(bp, priv_key, off, "priv:"))
                goto err;
        if (!bn_printf(bp, pub_key, off, "pub: "))
                goto err;
        if (!ECPKParameters_print(bp, group, off))
                goto err;

        ret = 1;

 err:
        if (!ret)
                ECerror(reason);
        BN_free(pub_key);
        BN_CTX_free(ctx);

        return (ret);
}

static int
eckey_param_decode(EVP_PKEY *pkey, const unsigned char **param, int param_len)
{
        EC_KEY *eckey;
        int ret = 0;

        if ((eckey = d2i_ECParameters(NULL, param, param_len)) == NULL)
                goto err;
        if (!EVP_PKEY_assign_EC_KEY(pkey, eckey))
                goto err;
        eckey = NULL;

        ret = 1;

 err:
        EC_KEY_free(eckey);

        return ret;
}

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

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 **priv, int priv_len)
{
        EC_KEY *eckey;
        int ret = 0;

        if ((eckey = d2i_ECPrivateKey(NULL, priv, priv_len)) == NULL)
                goto err;
        if (!EVP_PKEY_assign_EC_KEY(pkey, eckey))
                goto err;
        eckey = NULL;

        ret = 1;

 err:
        EC_KEY_free(eckey);

        return ret;
}

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

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;
                        if (!X509_ALGOR_set0_by_nid(alg2, snid, V_ASN1_UNDEF,
                            NULL))
                                return -1;
                }
                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;
                        if (!X509_ALGOR_set0_by_nid(alg2, snid, V_ASN1_UNDEF,
                            NULL))
                                return -1;
                }
                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;

        }

}

#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 {
                if (!eckey_from_params(atype, aval, &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;
        const ASN1_OBJECT *obj;
        int nid;
        const void *parameter;
        int parameter_type;
        ASN1_OCTET_STRING *ukm;
        const unsigned char *p;
        unsigned char *der = NULL;
        int plen, keylen;
        const EVP_CIPHER *kekcipher;
        EVP_CIPHER_CTX *kekctx;
        int ret = 0;

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

        X509_ALGOR_get0(&obj, &parameter_type, &parameter, alg);

        if ((nid = OBJ_obj2nid(obj)) == NID_undef)
                goto err;
        if (!ecdh_cms_set_kdf_param(pctx, nid)) {
                ECerror(EC_R_KDF_PARAMETER_ERROR);
                goto err;
        }

        if (parameter_type != V_ASN1_SEQUENCE)
                goto err;
        if ((p = ASN1_STRING_get0_data(parameter)) == NULL)
                goto err;
        plen = ASN1_STRING_length(parameter);
        if ((kekalg = d2i_X509_ALGOR(NULL, &p, plen)) == NULL)
                goto err;

        /*
         * XXX - the reaching into kekalg below is ugly, but unfortunately the
         * now internal legacy EVP_CIPHER_asn1_to_param() API doesn't interact
         * nicely with the X509_ALGOR API.
         */

        if ((kekctx = CMS_RecipientInfo_kari_get0_ctx(ri)) == NULL)
                goto err;
        if ((kekcipher = EVP_get_cipherbyobj(kekalg->algorithm)) == NULL)
                goto err;
        if (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;

        if ((plen = CMS_SharedInfo_encode(&der, kekalg, ukm, keylen)) <= 0)
                goto err;

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

        ret = 1;

 err:
        X509_ALGOR_free(kekalg);
        free(der);

        return ret;
}

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_CIPHER_CTX *ctx;
        int keylen;
        X509_ALGOR *talg, *wrap_alg = NULL;
        const ASN1_OBJECT *aoid;
        ASN1_BIT_STRING *pubkey;
        ASN1_STRING *wrap_str = NULL;
        ASN1_OCTET_STRING *ukm;
        unsigned char *penc = NULL;
        int penclen;
        int ecdh_nid, kdf_nid, wrap_nid;
        const EVP_MD *kdf_md;
        int ret = 0;

        if ((pctx = CMS_RecipientInfo_get0_pkey_ctx(ri)) == NULL)
                goto err;
        if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &talg, &pubkey,
            NULL, NULL, NULL))
                goto err;

        X509_ALGOR_get0(&aoid, NULL, NULL, talg);
        if (aoid == OBJ_nid2obj(NID_undef)) {
                EVP_PKEY *pkey;

                if ((pkey = EVP_PKEY_CTX_get0_pkey(pctx)) == NULL)
                        goto err;

                penc = NULL;
                if ((penclen = i2o_ECPublicKey(pkey->pkey.ec, &penc)) <= 0)
                        goto err;

                ASN1_STRING_set0(pubkey, penc, penclen);
                penc = NULL;

                if (!asn1_abs_set_unused_bits(pubkey, 0))
                        goto err;

                if (!X509_ALGOR_set0_by_nid(talg, NID_X9_62_id_ecPublicKey,
                    V_ASN1_UNDEF, NULL))
                        goto err;
        }

        if (EVP_PKEY_CTX_get_ecdh_kdf_type(pctx) != EVP_PKEY_ECDH_KDF_NONE)
                goto err;
        if (EVP_PKEY_CTX_set_ecdh_kdf_type(pctx, EVP_PKEY_ECDH_KDF_X9_63) <= 0)
                goto err;

        if ((ecdh_nid = EVP_PKEY_CTX_get_ecdh_cofactor_mode(pctx)) < 0)
                goto err;
        if (ecdh_nid == 0)
                ecdh_nid = NID_dh_std_kdf;
        else if (ecdh_nid == 1)
                ecdh_nid = NID_dh_cofactor_kdf;

        if (!EVP_PKEY_CTX_get_ecdh_kdf_md(pctx, &kdf_md))
                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.
         *
         * Incompatibility of X509_ALGOR_set0() with EVP_CIPHER_param_to_asn1()
         * makes this really gross. See the XXX in ecdh_cms_set_shared_info().
         */

        if ((wrap_alg = X509_ALGOR_new()) == NULL)
                goto err;
        if ((wrap_alg->algorithm = OBJ_nid2obj(wrap_nid)) == NULL)
                goto err;
        if ((wrap_alg->parameter = ASN1_TYPE_new()) == NULL)
                goto err;
        if (EVP_CIPHER_param_to_asn1(ctx, wrap_alg->parameter) <= 0)
                goto err;
        if (ASN1_TYPE_get(wrap_alg->parameter) == V_ASN1_UNDEF) {
                ASN1_TYPE_free(wrap_alg->parameter);
                wrap_alg->parameter = NULL;
        }

        if ((penclen = CMS_SharedInfo_encode(&penc, wrap_alg, ukm, keylen)) <= 0)
                goto err;

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

        /*
         * Wrap encoded wrap AlgorithmIdentifier into parameter of another
         * AlgorithmIdentifier.
         */

        if ((penclen = i2d_X509_ALGOR(wrap_alg, &penc)) <= 0)
                goto err;

        if ((wrap_str = ASN1_STRING_new()) == NULL)
                goto err;
        ASN1_STRING_set0(wrap_str, penc, penclen);
        penc = NULL;

        if (!X509_ALGOR_set0_by_nid(talg, kdf_nid, V_ASN1_SEQUENCE, wrap_str))
                goto err;
        wrap_str = NULL;

        ret = 1;

 err:
        free(penc);
        ASN1_STRING_free(wrap_str);
        X509_ALGOR_free(wrap_alg);

        return ret;
}

#endif

const EVP_PKEY_ASN1_METHOD eckey_asn1_meth = {
        .base_method = &eckey_asn1_meth,
        .pkey_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 = 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 = ec_free,
        .pkey_ctrl = ec_pkey_ctrl,
        .old_priv_decode = old_ec_priv_decode,
        .old_priv_encode = old_ec_priv_encode,
};