ec_pmeth.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/asn1t.h>
#include <openssl/x509.h>
#include <openssl/ec.h>
#include <openssl/ecdsa.h>
#include <openssl/evp.h>
#include "evp_locl.h"

/* EC pkey context structure */

typedef struct
    {
    /* Key and paramgen group */
    EC_GROUP *gen_group;
    /* message digest */
    const EVP_MD *md;
    } EC_PKEY_CTX;

static int pkey_ec_init(EVP_PKEY_CTX *ctx)
    {
    EC_PKEY_CTX *dctx;
    dctx = OPENSSL_malloc(sizeof(EC_PKEY_CTX));
    if (!dctx)
        return 0;
    dctx->gen_group = NULL;
    dctx->md = NULL;

    ctx->data = dctx;

    return 1;
    }

static int pkey_ec_copy(EVP_PKEY_CTX *dst, EVP_PKEY_CTX *src)
    {
    EC_PKEY_CTX *dctx, *sctx;
    if (!pkey_ec_init(dst))
        return 0;
        sctx = src->data;
    dctx = dst->data;
    if (sctx->gen_group)
        {
        dctx->gen_group = EC_GROUP_dup(sctx->gen_group);
        if (!dctx->gen_group)
            return 0;
        }
    dctx->md = sctx->md;
    return 1;
    }

static void pkey_ec_cleanup(EVP_PKEY_CTX *ctx)
    {
    EC_PKEY_CTX *dctx = ctx->data;
    if (dctx)
        {
        if (dctx->gen_group)
            EC_GROUP_free(dctx->gen_group);
        OPENSSL_free(dctx);
        }
    }

static int pkey_ec_sign(EVP_PKEY_CTX *ctx, unsigned char *sig, size_t *siglen,
                    const unsigned char *tbs, size_t tbslen)
    {
    int ret, type;
    unsigned int sltmp;
    EC_PKEY_CTX *dctx = ctx->data;
    EC_KEY *ec = ctx->pkey->pkey.ec;

    if (!sig)
        {
        *siglen = ECDSA_size(ec);
        return 1;
        }
    else if(*siglen < (size_t)ECDSA_size(ec))
        {
        ECerr(EC_F_PKEY_EC_SIGN, EC_R_BUFFER_TOO_SMALL);
        return 0;
        }

    if (dctx->md)
        type = EVP_MD_type(dctx->md);
    else
        type = NID_sha1;


    ret = ECDSA_sign(type, tbs, tbslen, sig, &sltmp, ec);

    if (ret <= 0)
        return ret;
    *siglen = (size_t)sltmp;
    return 1;
    }

static int pkey_ec_verify(EVP_PKEY_CTX *ctx,
                    const unsigned char *sig, size_t siglen,
                    const unsigned char *tbs, size_t tbslen)
    {
    int ret, type;
    EC_PKEY_CTX *dctx = ctx->data;
    EC_KEY *ec = ctx->pkey->pkey.ec;

    if (dctx->md)
        type = EVP_MD_type(dctx->md);
    else
        type = NID_sha1;

    ret = ECDSA_verify(type, tbs, tbslen, sig, siglen, ec);

    return ret;
    }

static int pkey_ec_derive(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *keylen)
    {
    int ret;
    size_t outlen;
    const EC_POINT *pubkey = NULL;
    if (!ctx->pkey || !ctx->peerkey)
        {
        ECerr(EC_F_PKEY_EC_DERIVE, EC_R_KEYS_NOT_SET);
        return 0;
        }

    if (!key)
        {
        const EC_GROUP *group;
        group = EC_KEY_get0_group(ctx->pkey->pkey.ec);
        *keylen = (EC_GROUP_get_degree(group) + 7)/8;
        return 1;
        }

    pubkey = EC_KEY_get0_public_key(ctx->peerkey->pkey.ec);

    /* NB: unlike PKS#3 DH, if *outlen is less than maximum size this is
     * not an error, the result is truncated.
     */

    outlen = *keylen;
        
    ret = ECDH_compute_key(key, outlen, pubkey, ctx->pkey->pkey.ec, 0);
    if (ret < 0)
        return ret;
    *keylen = ret;
    return 1;
    }

static int pkey_ec_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)
    {
    EC_PKEY_CTX *dctx = ctx->data;
    EC_GROUP *group;
    switch (type)
        {
        case EVP_PKEY_CTRL_EC_PARAMGEN_CURVE_NID:
        group = EC_GROUP_new_by_curve_name(p1);
        if (group == NULL)
            {
            ECerr(EC_F_PKEY_EC_CTRL, EC_R_INVALID_CURVE);
            return 0;
            }
        if (dctx->gen_group)
            EC_GROUP_free(dctx->gen_group);
        dctx->gen_group = group;
        return 1;

        case EVP_PKEY_CTRL_MD:
        if (EVP_MD_type((const EVP_MD *)p2) != NID_sha1 &&
            EVP_MD_type((const EVP_MD *)p2) != NID_ecdsa_with_SHA1 &&
            EVP_MD_type((const EVP_MD *)p2) != NID_sha224 &&
            EVP_MD_type((const EVP_MD *)p2) != NID_sha256 &&
            EVP_MD_type((const EVP_MD *)p2) != NID_sha384 &&
            EVP_MD_type((const EVP_MD *)p2) != NID_sha512)
            {
            ECerr(EC_F_PKEY_EC_CTRL, EC_R_INVALID_DIGEST_TYPE);
            return 0;
            }
        dctx->md = p2;
        return 1;

        case EVP_PKEY_CTRL_PEER_KEY:
        /* Default behaviour is OK */
        case EVP_PKEY_CTRL_DIGESTINIT:
        case EVP_PKEY_CTRL_PKCS7_SIGN:
        case EVP_PKEY_CTRL_CMS_SIGN:
        return 1;

        default:
        return -2;

        }
    }
            
static int pkey_ec_ctrl_str(EVP_PKEY_CTX *ctx,
            const char *type, const char *value)
    {
    if (!strcmp(type, "ec_paramgen_curve"))
        {
        int nid;
        nid = OBJ_sn2nid(value);
        if (nid == NID_undef)
            nid = OBJ_ln2nid(value);
        if (nid == NID_undef)
            {
            ECerr(EC_F_PKEY_EC_CTRL_STR, EC_R_INVALID_CURVE);
            return 0;
            }
        return EVP_PKEY_CTX_set_ec_paramgen_curve_nid(ctx, nid);
        }
    return -2;
    }

static int pkey_ec_paramgen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
    {
    EC_KEY *ec = NULL;
    EC_PKEY_CTX *dctx = ctx->data;
    int ret = 0;
    if (dctx->gen_group == NULL)
        {
        ECerr(EC_F_PKEY_EC_PARAMGEN, EC_R_NO_PARAMETERS_SET);
        return 0;
        }
    ec = EC_KEY_new();
    if (!ec)
        return 0;
    ret = EC_KEY_set_group(ec, dctx->gen_group);
    if (ret)
        EVP_PKEY_assign_EC_KEY(pkey, ec);
    else
        EC_KEY_free(ec);
    return ret;
    }

static int pkey_ec_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
    {
    EC_KEY *ec = NULL;
    if (ctx->pkey == NULL)
        {
        ECerr(EC_F_PKEY_EC_KEYGEN, EC_R_NO_PARAMETERS_SET);
        return 0;
        }
    ec = EC_KEY_new();
    if (!ec)
        return 0;
    EVP_PKEY_assign_EC_KEY(pkey, ec);
    /* Note: if error return, pkey is freed by parent routine */
    if (!EVP_PKEY_copy_parameters(pkey, ctx->pkey))
        return 0;
    return EC_KEY_generate_key(pkey->pkey.ec);
    }

const EVP_PKEY_METHOD ec_pkey_meth = 
    {
    EVP_PKEY_EC,
    0,
    pkey_ec_init,
    pkey_ec_copy,
    pkey_ec_cleanup,

    0,
    pkey_ec_paramgen,

    0,
    pkey_ec_keygen,

    0,
    pkey_ec_sign,

    0,
    pkey_ec_verify,

    0,0,

    0,0,0,0,

    0,0,

    0,0,

    0,
    pkey_ec_derive,

    pkey_ec_ctrl,
    pkey_ec_ctrl_str

    };