/**********************************************************************
 *                          gost_ameth.c                              *
 *             Copyright (c) 2005-2006 Cryptocom LTD                  *
 *         This file is distributed under the same license as OpenSSL *
 *                                                                    *
 *       Implementation of RFC 4490/4491 ASN1 method                  *
 *       for OpenSSL                                                  *
 *          Requires OpenSSL 0.9.9 for compilation                    *
 **********************************************************************/
#include <string.h>
#include <openssl/crypto.h>
#include <openssl/err.h>
#include <openssl/engine.h>
#include <openssl/evp.h>
#include <openssl/asn1.h>
#include "gost_params.h"
#include "gost_lcl.h"
#include "e_gost_err.h"

int gost94_nid_by_params(DSA *p)
{
    R3410_params *gost_params;
    BIGNUM *q = BN_new();
    for (gost_params = R3410_paramset; gost_params->q != NULL; gost_params++) {
        BN_dec2bn(&q, gost_params->q);
        if (!BN_cmp(q, p->q)) {
            BN_free(q);
            return gost_params->nid;
        }
    }
    BN_free(q);
    return NID_undef;
}

static ASN1_STRING *encode_gost_algor_params(const EVP_PKEY *key)
{
    ASN1_STRING *params = ASN1_STRING_new();
    GOST_KEY_PARAMS *gkp = GOST_KEY_PARAMS_new();
    int pkey_param_nid = NID_undef;

    if (!params || !gkp) {
        GOSTerr(GOST_F_ENCODE_GOST_ALGOR_PARAMS, ERR_R_MALLOC_FAILURE);
        ASN1_STRING_free(params);
        params = NULL;
        goto err;
    }
    switch (EVP_PKEY_base_id(key)) {
    case NID_id_GostR3410_2001:
        pkey_param_nid =
            EC_GROUP_get_curve_name(EC_KEY_get0_group
                                    (EVP_PKEY_get0((EVP_PKEY *)key)));
        break;
    case NID_id_GostR3410_94:
        pkey_param_nid =
            (int)gost94_nid_by_params(EVP_PKEY_get0((EVP_PKEY *)key));
        if (pkey_param_nid == NID_undef) {
            GOSTerr(GOST_F_ENCODE_GOST_ALGOR_PARAMS,
                    GOST_R_INVALID_GOST94_PARMSET);
            ASN1_STRING_free(params);
            params = NULL;
            goto err;
        }
        break;
    }
    gkp->key_params = OBJ_nid2obj(pkey_param_nid);
    gkp->hash_params = OBJ_nid2obj(NID_id_GostR3411_94_CryptoProParamSet);
    /*
     * gkp->cipher_params = OBJ_nid2obj(cipher_param_nid);
     */
    params->length = i2d_GOST_KEY_PARAMS(gkp, &params->data);
    if (params->length <= 0) {
        GOSTerr(GOST_F_ENCODE_GOST_ALGOR_PARAMS, ERR_R_MALLOC_FAILURE);
        ASN1_STRING_free(params);
        params = NULL;
        goto err;
    }
    params->type = V_ASN1_SEQUENCE;
 err:
    GOST_KEY_PARAMS_free(gkp);
    return params;
}

/*
 * Parses GOST algorithm parameters from X509_ALGOR and modifies pkey setting
 * NID and parameters
 */
static int decode_gost_algor_params(EVP_PKEY *pkey, X509_ALGOR *palg)
{
    ASN1_OBJECT *palg_obj = NULL;
    int ptype = V_ASN1_UNDEF;
    int pkey_nid = NID_undef, param_nid = NID_undef;
    void *_pval;
    ASN1_STRING *pval = NULL;
    const unsigned char *p;
    GOST_KEY_PARAMS *gkp = NULL;

    X509_ALGOR_get0(&palg_obj, &ptype, &_pval, palg);
    pval = _pval;
    if (ptype != V_ASN1_SEQUENCE) {
        GOSTerr(GOST_F_DECODE_GOST_ALGOR_PARAMS,
                GOST_R_BAD_KEY_PARAMETERS_FORMAT);
        return 0;
    }
    p = pval->data;
    pkey_nid = OBJ_obj2nid(palg_obj);

    gkp = d2i_GOST_KEY_PARAMS(NULL, &p, pval->length);
    if (!gkp) {
        GOSTerr(GOST_F_DECODE_GOST_ALGOR_PARAMS,
                GOST_R_BAD_PKEY_PARAMETERS_FORMAT);
        return 0;
    }
    param_nid = OBJ_obj2nid(gkp->key_params);
    GOST_KEY_PARAMS_free(gkp);
    EVP_PKEY_set_type(pkey, pkey_nid);
    switch (pkey_nid) {
    case NID_id_GostR3410_94:
        {
            DSA *dsa = EVP_PKEY_get0(pkey);
            if (!dsa) {
                dsa = DSA_new();
                if (!EVP_PKEY_assign(pkey, pkey_nid, dsa))
                    return 0;
            }
            if (!fill_GOST94_params(dsa, param_nid))
                return 0;
            break;
        }
    case NID_id_GostR3410_2001:
        {
            EC_KEY *ec = EVP_PKEY_get0(pkey);
            if (!ec) {
                ec = EC_KEY_new();
                if (!EVP_PKEY_assign(pkey, pkey_nid, ec))
                    return 0;
            }
            if (!fill_GOST2001_params(ec, param_nid))
                return 0;
        }
    }

    return 1;
}

static int gost_set_priv_key(EVP_PKEY *pkey, BIGNUM *priv)
{
    switch (EVP_PKEY_base_id(pkey)) {
    case NID_id_GostR3410_94:
        {
            DSA *dsa = EVP_PKEY_get0(pkey);
            if (!dsa) {
                dsa = DSA_new();
                EVP_PKEY_assign(pkey, EVP_PKEY_base_id(pkey), dsa);
            }
            dsa->priv_key = BN_dup(priv);
            if (!EVP_PKEY_missing_parameters(pkey))
                gost94_compute_public(dsa);
            break;
        }
    case NID_id_GostR3410_2001:
        {
            EC_KEY *ec = EVP_PKEY_get0(pkey);
            if (!ec) {
                ec = EC_KEY_new();
                EVP_PKEY_assign(pkey, EVP_PKEY_base_id(pkey), ec);
            }
            if (!EC_KEY_set_private_key(ec, priv))
                return 0;
            if (!EVP_PKEY_missing_parameters(pkey))
                gost2001_compute_public(ec);
            break;
        }
    }
    return 1;
}

BIGNUM *gost_get0_priv_key(const EVP_PKEY *pkey)
{
    switch (EVP_PKEY_base_id(pkey)) {
    case NID_id_GostR3410_94:
        {
            DSA *dsa = EVP_PKEY_get0((EVP_PKEY *)pkey);
            if (!dsa) {
                return NULL;
            }
            if (!dsa->priv_key)
                return NULL;
            return dsa->priv_key;
            break;
        }
    case NID_id_GostR3410_2001:
        {
            EC_KEY *ec = EVP_PKEY_get0((EVP_PKEY *)pkey);
            const BIGNUM *priv;
            if (!ec) {
                return NULL;
            }
            if (!(priv = EC_KEY_get0_private_key(ec)))
                return NULL;
            return (BIGNUM *)priv;
            break;
        }
    }
    return NULL;
}

static int pkey_ctrl_gost(EVP_PKEY *pkey, int op, long arg1, void *arg2)
{
    switch (op) {
    case ASN1_PKEY_CTRL_PKCS7_SIGN:
        if (arg1 == 0) {
            X509_ALGOR *alg1 = NULL, *alg2 = NULL;
            int nid = EVP_PKEY_base_id(pkey);
            PKCS7_SIGNER_INFO_get0_algs((PKCS7_SIGNER_INFO *)arg2,
                                        NULL, &alg1, &alg2);
            X509_ALGOR_set0(alg1, OBJ_nid2obj(NID_id_GostR3411_94),
                            V_ASN1_NULL, 0);
            if (nid == NID_undef) {
                return (-1);
            }
            X509_ALGOR_set0(alg2, OBJ_nid2obj(nid), V_ASN1_NULL, 0);
        }
        return 1;
    case ASN1_PKEY_CTRL_PKCS7_ENCRYPT:
        if (arg1 == 0) {
            X509_ALGOR *alg;
            ASN1_STRING *params = encode_gost_algor_params(pkey);
            if (!params) {
                return -1;
            }
            PKCS7_RECIP_INFO_get0_alg((PKCS7_RECIP_INFO *)arg2, &alg);
            X509_ALGOR_set0(alg, OBJ_nid2obj(pkey->type),
                            V_ASN1_SEQUENCE, params);
        }
        return 1;
    case ASN1_PKEY_CTRL_DEFAULT_MD_NID:
        *(int *)arg2 = NID_id_GostR3411_94;
        return 2;
    }

    return -2;
}

/* --------------------- free functions * ------------------------------*/
static void pkey_free_gost94(EVP_PKEY *key)
{
    if (key->pkey.dsa) {
        DSA_free(key->pkey.dsa);
    }
}

static void pkey_free_gost01(EVP_PKEY *key)
{
    if (key->pkey.ec) {
        EC_KEY_free(key->pkey.ec);
    }
}

/* ------------------ private key functions  -----------------------------*/
static int priv_decode_gost(EVP_PKEY *pk, PKCS8_PRIV_KEY_INFO *p8inf)
{
    const unsigned char *pkey_buf = NULL, *p = NULL;
    int priv_len = 0;
    BIGNUM *pk_num = NULL;
    int ret = 0;
    X509_ALGOR *palg = NULL;
    ASN1_OBJECT *palg_obj = NULL;
    ASN1_INTEGER *priv_key = NULL;

    if (!PKCS8_pkey_get0(&palg_obj, &pkey_buf, &priv_len, &palg, p8inf))
        return 0;
    p = pkey_buf;
    if (!decode_gost_algor_params(pk, palg)) {
        return 0;
    }
    if (V_ASN1_OCTET_STRING == *p) {
        /* New format - Little endian octet string */
        unsigned char rev_buf[32];
        int i;
        ASN1_OCTET_STRING *s = d2i_ASN1_OCTET_STRING(NULL, &p, priv_len);
        if (!s || s->length != 32) {
            GOSTerr(GOST_F_PRIV_DECODE_GOST, EVP_R_DECODE_ERROR);
            return 0;
        }
        for (i = 0; i < 32; i++) {
            rev_buf[31 - i] = s->data[i];
        }
        ASN1_STRING_free(s);
        pk_num = getbnfrombuf(rev_buf, 32);
    } else {
        priv_key = d2i_ASN1_INTEGER(NULL, &p, priv_len);
        if (!priv_key)
            return 0;
        ret = ((pk_num = ASN1_INTEGER_to_BN(priv_key, NULL)) != NULL);
        ASN1_INTEGER_free(priv_key);
        if (!ret) {
            GOSTerr(GOST_F_PRIV_DECODE_GOST, EVP_R_DECODE_ERROR);
            return 0;
        }
    }

    ret = gost_set_priv_key(pk, pk_num);
    BN_free(pk_num);
    return ret;
}

/* ----------------------------------------------------------------------*/
static int priv_encode_gost(PKCS8_PRIV_KEY_INFO *p8, const EVP_PKEY *pk)
{
    ASN1_OBJECT *algobj = OBJ_nid2obj(EVP_PKEY_base_id(pk));
    ASN1_STRING *params = encode_gost_algor_params(pk);
    unsigned char *priv_buf = NULL;
    int priv_len;

    ASN1_INTEGER *asn1key = NULL;
    if (!params) {
        return 0;
    }
    asn1key = BN_to_ASN1_INTEGER(gost_get0_priv_key(pk), NULL);
    priv_len = i2d_ASN1_INTEGER(asn1key, &priv_buf);
    ASN1_INTEGER_free(asn1key);
    return PKCS8_pkey_set0(p8, algobj, 0, V_ASN1_SEQUENCE, params,
                           priv_buf, priv_len);
}

/* --------- printing keys --------------------------------*/
static int print_gost_94(BIO *out, const EVP_PKEY *pkey, int indent,
                         ASN1_PCTX *pctx, int type)
{
    int param_nid = NID_undef;

    if (type == 2) {
        BIGNUM *key;

        if (!BIO_indent(out, indent, 128))
            return 0;
        BIO_printf(out, "Private key: ");
        key = gost_get0_priv_key(pkey);
        if (!key)
            BIO_printf(out, "<undefined>");
        else
            BN_print(out, key);
        BIO_printf(out, "\n");
    }
    if (type >= 1) {
        BIGNUM *pubkey;

        pubkey = ((DSA *)EVP_PKEY_get0((EVP_PKEY *)pkey))->pub_key;
        BIO_indent(out, indent, 128);
        BIO_printf(out, "Public key: ");
        BN_print(out, pubkey);
        BIO_printf(out, "\n");
    }

    param_nid = gost94_nid_by_params(EVP_PKEY_get0((EVP_PKEY *)pkey));
    BIO_indent(out, indent, 128);
    BIO_printf(out, "Parameter set: %s\n", OBJ_nid2ln(param_nid));
    return 1;
}

static int param_print_gost94(BIO *out, const EVP_PKEY *pkey, int indent,
                              ASN1_PCTX *pctx)
{
    return print_gost_94(out, pkey, indent, pctx, 0);
}

static int pub_print_gost94(BIO *out, const EVP_PKEY *pkey, int indent,
                            ASN1_PCTX *pctx)
{
    return print_gost_94(out, pkey, indent, pctx, 1);
}

static int priv_print_gost94(BIO *out, const EVP_PKEY *pkey, int indent,
                             ASN1_PCTX *pctx)
{
    return print_gost_94(out, pkey, indent, pctx, 2);
}

static int print_gost_01(BIO *out, const EVP_PKEY *pkey, int indent,
                         ASN1_PCTX *pctx, int type)
{
    int param_nid = NID_undef;
    if (type == 2) {
        BIGNUM *key;

        if (!BIO_indent(out, indent, 128))
            return 0;
        BIO_printf(out, "Private key: ");
        key = gost_get0_priv_key(pkey);
        if (!key)
            BIO_printf(out, "<undefined)");
        else
            BN_print(out, key);
        BIO_printf(out, "\n");
    }
    if (type >= 1) {
        BN_CTX *ctx = BN_CTX_new();
        BIGNUM *X, *Y;
        const EC_POINT *pubkey;
        const EC_GROUP *group;

        if (!ctx) {
            GOSTerr(GOST_F_PRINT_GOST_01, ERR_R_MALLOC_FAILURE);
            return 0;
        }
        BN_CTX_start(ctx);
        X = BN_CTX_get(ctx);
        Y = BN_CTX_get(ctx);
        pubkey =
            EC_KEY_get0_public_key((EC_KEY *)EVP_PKEY_get0((EVP_PKEY *)pkey));
        group = EC_KEY_get0_group((EC_KEY *)EVP_PKEY_get0((EVP_PKEY *)pkey));
        if (!EC_POINT_get_affine_coordinates_GFp(group, pubkey, X, Y, ctx)) {
            GOSTerr(GOST_F_PRINT_GOST_01, ERR_R_EC_LIB);
            BN_CTX_free(ctx);
            return 0;
        }
        if (!BIO_indent(out, indent, 128))
            return 0;
        BIO_printf(out, "Public key:\n");
        if (!BIO_indent(out, indent + 3, 128))
            return 0;
        BIO_printf(out, "X:");
        BN_print(out, X);
        BIO_printf(out, "\n");
        BIO_indent(out, indent + 3, 128);
        BIO_printf(out, "Y:");
        BN_print(out, Y);
        BIO_printf(out, "\n");
        BN_CTX_end(ctx);
        BN_CTX_free(ctx);
    }

    param_nid =
        EC_GROUP_get_curve_name(EC_KEY_get0_group
                                (EVP_PKEY_get0((EVP_PKEY *)pkey)));
    if (!BIO_indent(out, indent, 128))
        return 0;
    BIO_printf(out, "Parameter set: %s\n", OBJ_nid2ln(param_nid));
    return 1;
}

static int param_print_gost01(BIO *out, const EVP_PKEY *pkey, int indent,
                              ASN1_PCTX *pctx)
{
    return print_gost_01(out, pkey, indent, pctx, 0);
}

static int pub_print_gost01(BIO *out, const EVP_PKEY *pkey, int indent,
                            ASN1_PCTX *pctx)
{
    return print_gost_01(out, pkey, indent, pctx, 1);
}

static int priv_print_gost01(BIO *out, const EVP_PKEY *pkey, int indent,
                             ASN1_PCTX *pctx)
{
    return print_gost_01(out, pkey, indent, pctx, 2);
}

/* ---------------------------------------------------------------------*/
static int param_missing_gost94(const EVP_PKEY *pk)
{
    const DSA *dsa = EVP_PKEY_get0((EVP_PKEY *)pk);
    if (!dsa)
        return 1;
    if (!dsa->q)
        return 1;
    return 0;
}

static int param_missing_gost01(const EVP_PKEY *pk)
{
    const EC_KEY *ec = EVP_PKEY_get0((EVP_PKEY *)pk);
    if (!ec)
        return 1;
    if (!EC_KEY_get0_group(ec))
        return 1;
    return 0;
}

static int param_copy_gost94(EVP_PKEY *to, const EVP_PKEY *from)
{
    const DSA *dfrom = EVP_PKEY_get0((EVP_PKEY *)from);
    DSA *dto = EVP_PKEY_get0(to);
    if (EVP_PKEY_base_id(from) != EVP_PKEY_base_id(to)) {
        GOSTerr(GOST_F_PARAM_COPY_GOST94, GOST_R_INCOMPATIBLE_ALGORITHMS);
        return 0;
    }
    if (!dfrom) {
        GOSTerr(GOST_F_PARAM_COPY_GOST94, GOST_R_KEY_PARAMETERS_MISSING);
        return 0;
    }
    if (!dto) {
        dto = DSA_new();
        EVP_PKEY_assign(to, EVP_PKEY_base_id(from), dto);
    }
#define COPYBIGNUM(a,b,x) if (a->x) BN_free(a->x); a->x=BN_dup(b->x);
    COPYBIGNUM(dto, dfrom, p)
        COPYBIGNUM(dto, dfrom, q)
        COPYBIGNUM(dto, dfrom, g)

        if (dto->priv_key)
        gost94_compute_public(dto);
    return 1;
}

static int param_copy_gost01(EVP_PKEY *to, const EVP_PKEY *from)
{
    EC_KEY *eto = EVP_PKEY_get0(to);
    const EC_KEY *efrom = EVP_PKEY_get0((EVP_PKEY *)from);
    if (EVP_PKEY_base_id(from) != EVP_PKEY_base_id(to)) {
        GOSTerr(GOST_F_PARAM_COPY_GOST01, GOST_R_INCOMPATIBLE_ALGORITHMS);
        return 0;
    }
    if (!efrom) {
        GOSTerr(GOST_F_PARAM_COPY_GOST01, GOST_R_KEY_PARAMETERS_MISSING);
        return 0;
    }
    if (!eto) {
        eto = EC_KEY_new();
        EVP_PKEY_assign(to, EVP_PKEY_base_id(from), eto);
    }
    EC_KEY_set_group(eto, EC_KEY_get0_group(efrom));
    if (EC_KEY_get0_private_key(eto)) {
        gost2001_compute_public(eto);
    }
    return 1;
}

static int param_cmp_gost94(const EVP_PKEY *a, const EVP_PKEY *b)
{
    const DSA *da = EVP_PKEY_get0((EVP_PKEY *)a);
    const DSA *db = EVP_PKEY_get0((EVP_PKEY *)b);
    if (!BN_cmp(da->q, db->q))
        return 1;
    return 0;
}

static int param_cmp_gost01(const EVP_PKEY *a, const EVP_PKEY *b)
{
    if (EC_GROUP_get_curve_name
        (EC_KEY_get0_group(EVP_PKEY_get0((EVP_PKEY *)a))) ==
        EC_GROUP_get_curve_name(EC_KEY_get0_group
                                (EVP_PKEY_get0((EVP_PKEY *)b)))) {
        return 1;
    }
    return 0;

}

/* ---------- Public key functions * --------------------------------------*/
static int pub_decode_gost94(EVP_PKEY *pk, X509_PUBKEY *pub)
{
    X509_ALGOR *palg = NULL;
    const unsigned char *pubkey_buf = NULL;
    unsigned char *databuf;
    ASN1_OBJECT *palgobj = NULL;
    int pub_len, i, j;
    DSA *dsa;
    ASN1_OCTET_STRING *octet = NULL;

    if (!X509_PUBKEY_get0_param(&palgobj, &pubkey_buf, &pub_len, &palg, pub))
        return 0;
    EVP_PKEY_assign(pk, OBJ_obj2nid(palgobj), NULL);
    if (!decode_gost_algor_params(pk, palg))
        return 0;
    octet = d2i_ASN1_OCTET_STRING(NULL, &pubkey_buf, pub_len);
    if (!octet) {
        GOSTerr(GOST_F_PUB_DECODE_GOST94, ERR_R_MALLOC_FAILURE);
        return 0;
    }
    databuf = OPENSSL_malloc(octet->length);
    for (i = 0, j = octet->length - 1; i < octet->length; i++, j--) {
        databuf[j] = octet->data[i];
    }
    dsa = EVP_PKEY_get0(pk);
    dsa->pub_key = BN_bin2bn(databuf, octet->length, NULL);
    ASN1_OCTET_STRING_free(octet);
    OPENSSL_free(databuf);
    return 1;

}

static int pub_encode_gost94(X509_PUBKEY *pub, const EVP_PKEY *pk)
{
    ASN1_OBJECT *algobj = NULL;
    ASN1_OCTET_STRING *octet = NULL;
    void *pval = NULL;
    unsigned char *buf = NULL, *databuf, *sptr;
    int i, j, data_len, ret = 0;

    int ptype = V_ASN1_UNDEF;
    DSA *dsa = EVP_PKEY_get0((EVP_PKEY *)pk);
    algobj = OBJ_nid2obj(EVP_PKEY_base_id(pk));
    if (pk->save_parameters) {
        ASN1_STRING *params = encode_gost_algor_params(pk);
        pval = params;
        ptype = V_ASN1_SEQUENCE;
    }
    data_len = BN_num_bytes(dsa->pub_key);
    databuf = OPENSSL_malloc(data_len);
    BN_bn2bin(dsa->pub_key, databuf);
    octet = ASN1_OCTET_STRING_new();
    ASN1_STRING_set(octet, NULL, data_len);
    sptr = ASN1_STRING_data(octet);
    for (i = 0, j = data_len - 1; i < data_len; i++, j--) {
        sptr[i] = databuf[j];
    }
    OPENSSL_free(databuf);
    ret = i2d_ASN1_OCTET_STRING(octet, &buf);
    ASN1_BIT_STRING_free(octet);
    if (ret < 0)
        return 0;
    return X509_PUBKEY_set0_param(pub, algobj, ptype, pval, buf, ret);
}

static int pub_decode_gost01(EVP_PKEY *pk, X509_PUBKEY *pub)
{
    X509_ALGOR *palg = NULL;
    const unsigned char *pubkey_buf = NULL;
    unsigned char *databuf;
    ASN1_OBJECT *palgobj = NULL;
    int pub_len, i, j;
    EC_POINT *pub_key;
    BIGNUM *X, *Y;
    ASN1_OCTET_STRING *octet = NULL;
    int len;
    const EC_GROUP *group;

    if (!X509_PUBKEY_get0_param(&palgobj, &pubkey_buf, &pub_len, &palg, pub))
        return 0;
    EVP_PKEY_assign(pk, OBJ_obj2nid(palgobj), NULL);
    if (!decode_gost_algor_params(pk, palg))
        return 0;
    group = EC_KEY_get0_group(EVP_PKEY_get0(pk));
    octet = d2i_ASN1_OCTET_STRING(NULL, &pubkey_buf, pub_len);
    if (!octet) {
        GOSTerr(GOST_F_PUB_DECODE_GOST01, ERR_R_MALLOC_FAILURE);
        return 0;
    }
    databuf = OPENSSL_malloc(octet->length);
    for (i = 0, j = octet->length - 1; i < octet->length; i++, j--) {
        databuf[j] = octet->data[i];
    }
    len = octet->length / 2;
    ASN1_OCTET_STRING_free(octet);

    Y = getbnfrombuf(databuf, len);
    X = getbnfrombuf(databuf + len, len);
    OPENSSL_free(databuf);
    pub_key = EC_POINT_new(group);
    if (!EC_POINT_set_affine_coordinates_GFp(group, pub_key, X, Y, NULL)) {
        GOSTerr(GOST_F_PUB_DECODE_GOST01, ERR_R_EC_LIB);
        EC_POINT_free(pub_key);
        BN_free(X);
        BN_free(Y);
        return 0;
    }
    BN_free(X);
    BN_free(Y);
    if (!EC_KEY_set_public_key(EVP_PKEY_get0(pk), pub_key)) {
        GOSTerr(GOST_F_PUB_DECODE_GOST01, ERR_R_EC_LIB);
        EC_POINT_free(pub_key);
        return 0;
    }
    EC_POINT_free(pub_key);
    return 1;

}

static int pub_encode_gost01(X509_PUBKEY *pub, const EVP_PKEY *pk)
{
    ASN1_OBJECT *algobj = NULL;
    ASN1_OCTET_STRING *octet = NULL;
    void *pval = NULL;
    unsigned char *buf = NULL, *databuf, *sptr;
    int i, j, data_len, ret = 0;
    const EC_POINT *pub_key;
    BIGNUM *X, *Y, *order;
    const EC_KEY *ec = EVP_PKEY_get0((EVP_PKEY *)pk);
    int ptype = V_ASN1_UNDEF;

    algobj = OBJ_nid2obj(EVP_PKEY_base_id(pk));
    if (pk->save_parameters) {
        ASN1_STRING *params = encode_gost_algor_params(pk);
        pval = params;
        ptype = V_ASN1_SEQUENCE;
    }
    order = BN_new();
    EC_GROUP_get_order(EC_KEY_get0_group(ec), order, NULL);
    pub_key = EC_KEY_get0_public_key(ec);
    if (!pub_key) {
        GOSTerr(GOST_F_PUB_ENCODE_GOST01, GOST_R_PUBLIC_KEY_UNDEFINED);
        return 0;
    }
    X = BN_new();
    Y = BN_new();
    EC_POINT_get_affine_coordinates_GFp(EC_KEY_get0_group(ec),
                                        pub_key, X, Y, NULL);
    data_len = 2 * BN_num_bytes(order);
    BN_free(order);
    databuf = OPENSSL_malloc(data_len);
    memset(databuf, 0, data_len);

    store_bignum(X, databuf + data_len / 2, data_len / 2);
    store_bignum(Y, databuf, data_len / 2);

    BN_free(X);
    BN_free(Y);
    octet = ASN1_OCTET_STRING_new();
    ASN1_STRING_set(octet, NULL, data_len);
    sptr = ASN1_STRING_data(octet);
    for (i = 0, j = data_len - 1; i < data_len; i++, j--) {
        sptr[i] = databuf[j];
    }
    OPENSSL_free(databuf);
    ret = i2d_ASN1_OCTET_STRING(octet, &buf);
    ASN1_BIT_STRING_free(octet);
    if (ret < 0)
        return 0;
    return X509_PUBKEY_set0_param(pub, algobj, ptype, pval, buf, ret);
}

static int pub_cmp_gost94(const EVP_PKEY *a, const EVP_PKEY *b)
{
    const DSA *da = EVP_PKEY_get0((EVP_PKEY *)a);
    const DSA *db = EVP_PKEY_get0((EVP_PKEY *)b);
    if (da && db && da->pub_key && db->pub_key
        && !BN_cmp(da->pub_key, db->pub_key)) {
        return 1;
    }
    return 0;
}

static int pub_cmp_gost01(const EVP_PKEY *a, const EVP_PKEY *b)
{
    const EC_KEY *ea = EVP_PKEY_get0((EVP_PKEY *)a);
    const EC_KEY *eb = EVP_PKEY_get0((EVP_PKEY *)b);
    const EC_POINT *ka, *kb;
    int ret = 0;
    if (!ea || !eb)
        return 0;
    ka = EC_KEY_get0_public_key(ea);
    kb = EC_KEY_get0_public_key(eb);
    if (!ka || !kb)
        return 0;
    ret = (0 == EC_POINT_cmp(EC_KEY_get0_group(ea), ka, kb, NULL));
    return ret;
}

static int pkey_size_gost(const EVP_PKEY *pk)
{
    return 64;
}

static int pkey_bits_gost(const EVP_PKEY *pk)
{
    return 256;
}

/* ---------------------- ASN1 METHOD for GOST MAC  -------------------*/
static void mackey_free_gost(EVP_PKEY *pk)
{
    if (pk->pkey.ptr) {
        OPENSSL_free(pk->pkey.ptr);
    }
}

static int mac_ctrl_gost(EVP_PKEY *pkey, int op, long arg1, void *arg2)
{
    switch (op) {
    case ASN1_PKEY_CTRL_DEFAULT_MD_NID:
        *(int *)arg2 = NID_id_Gost28147_89_MAC;
        return 2;
    }
    return -2;
}

static int gost94_param_encode(const EVP_PKEY *pkey, unsigned char **pder)
{
    int nid = gost94_nid_by_params(EVP_PKEY_get0((EVP_PKEY *)pkey));
    return i2d_ASN1_OBJECT(OBJ_nid2obj(nid), pder);
}

static int gost2001_param_encode(const EVP_PKEY *pkey, unsigned char **pder)
{
    int nid =
        EC_GROUP_get_curve_name(EC_KEY_get0_group
                                (EVP_PKEY_get0((EVP_PKEY *)pkey)));
    return i2d_ASN1_OBJECT(OBJ_nid2obj(nid), pder);
}

static int gost94_param_decode(EVP_PKEY *pkey, const unsigned char **pder,
                               int derlen)
{
    ASN1_OBJECT *obj = NULL;
    DSA *dsa = EVP_PKEY_get0(pkey);
    int nid;
    if (d2i_ASN1_OBJECT(&obj, pder, derlen) == NULL) {
        return 0;
    }
    nid = OBJ_obj2nid(obj);
    ASN1_OBJECT_free(obj);
    if (!dsa) {
        dsa = DSA_new();
        if (!EVP_PKEY_assign(pkey, NID_id_GostR3410_94, dsa))
            return 0;
    }
    if (!fill_GOST94_params(dsa, nid))
        return 0;
    return 1;
}

static int gost2001_param_decode(EVP_PKEY *pkey, const unsigned char **pder,
                                 int derlen)
{
    ASN1_OBJECT *obj = NULL;
    int nid;
    EC_KEY *ec = EVP_PKEY_get0(pkey);
    if (d2i_ASN1_OBJECT(&obj, pder, derlen) == NULL) {
        return 0;
    }
    nid = OBJ_obj2nid(obj);
    ASN1_OBJECT_free(obj);
    if (!ec) {
        ec = EC_KEY_new();
        if (!EVP_PKEY_assign(pkey, NID_id_GostR3410_2001, ec))
            return 0;
    }
    if (!fill_GOST2001_params(ec, nid))
        return 0;
    return 1;
}

/* ----------------------------------------------------------------------*/
int register_ameth_gost(int nid, EVP_PKEY_ASN1_METHOD **ameth,
                        const char *pemstr, const char *info)
{
    *ameth = EVP_PKEY_asn1_new(nid, ASN1_PKEY_SIGPARAM_NULL, pemstr, info);
    if (!*ameth)
        return 0;
    switch (nid) {
    case NID_id_GostR3410_94:
        EVP_PKEY_asn1_set_free(*ameth, pkey_free_gost94);
        EVP_PKEY_asn1_set_private(*ameth,
                                  priv_decode_gost, priv_encode_gost,
                                  priv_print_gost94);

        EVP_PKEY_asn1_set_param(*ameth,
                                gost94_param_decode, gost94_param_encode,
                                param_missing_gost94, param_copy_gost94,
                                param_cmp_gost94, param_print_gost94);
        EVP_PKEY_asn1_set_public(*ameth,
                                 pub_decode_gost94, pub_encode_gost94,
                                 pub_cmp_gost94, pub_print_gost94,
                                 pkey_size_gost, pkey_bits_gost);

        EVP_PKEY_asn1_set_ctrl(*ameth, pkey_ctrl_gost);
        break;
    case NID_id_GostR3410_2001:
        EVP_PKEY_asn1_set_free(*ameth, pkey_free_gost01);
        EVP_PKEY_asn1_set_private(*ameth,
                                  priv_decode_gost, priv_encode_gost,
                                  priv_print_gost01);

        EVP_PKEY_asn1_set_param(*ameth,
                                gost2001_param_decode, gost2001_param_encode,
                                param_missing_gost01, param_copy_gost01,
                                param_cmp_gost01, param_print_gost01);
        EVP_PKEY_asn1_set_public(*ameth,
                                 pub_decode_gost01, pub_encode_gost01,
                                 pub_cmp_gost01, pub_print_gost01,
                                 pkey_size_gost, pkey_bits_gost);

        EVP_PKEY_asn1_set_ctrl(*ameth, pkey_ctrl_gost);
        break;
    case NID_id_Gost28147_89_MAC:
        EVP_PKEY_asn1_set_free(*ameth, mackey_free_gost);
        EVP_PKEY_asn1_set_ctrl(*ameth, mac_ctrl_gost);
        break;
    }
    return 1;
}