ec_ameth.c

Go to the documentation of this file.

/* Written by Dr Stephen N Henson ([email protected]) 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
 *    [email protected].
 *
 * 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
 * ([email protected]).  This product includes software written by Tim
 * Hudson ([email protected]).
 *
 */

#include <stdio.h>
#include "cryptlib.h"
#include <openssl/x509.h>
#include <openssl/ec.h>
#include <openssl/bn.h>
#ifndef OPENSSL_NO_CMS
#include <openssl/cms.h>
#endif
#include "asn1_locl.h"

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

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

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

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

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

    return eckey;

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

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

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

    eckey = eckey_type2param(ptype, pval);

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

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

    EVP_PKEY_assign_EC_KEY(pkey, eckey);
    return 1;

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

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

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

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

    eckey = eckey_type2param(ptype, pval);

    if (!eckey)
        goto ecliberr;

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

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

    EVP_PKEY_assign_EC_KEY(pkey, eckey);
    return 1;

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

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

    ec_key = pkey->pkey.ec;

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

    /* set the private key */

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

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

    return 1;
}

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

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

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

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

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

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

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

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

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

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

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

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

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

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


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

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

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

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)
            {
            int snid, hnid;
            X509_ALGOR *alg1, *alg2;
            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;
#endif

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

        default:
        return -2;

        }

    }

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

    eckey_pub_decode,
    eckey_pub_encode,
    eckey_pub_cmp,
    eckey_pub_print,

    eckey_priv_decode,
    eckey_priv_encode,
    eckey_priv_print,

    int_ec_size,
    ec_bits,

    eckey_param_decode,
    eckey_param_encode,
    ec_missing_parameters,
    ec_copy_parameters,
    ec_cmp_parameters,
    eckey_param_print,
    0,

    int_ec_free,
    ec_pkey_ctrl,
    old_ec_priv_decode,
    old_ec_priv_encode
    };