/*

 * 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 "cryptlib.h"

#include <openssl/asn1t.h>

#include <openssl/x509.h>

#include <openssl/ec.h>

#include "ec_lcl.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;

    /* Duplicate key if custom cofactor needed */

    EC_KEY *co_key;

    /* Cofactor mode */

    signed char cofactor_mode;

    /* KDF (if any) to use for ECDH */

    char kdf_type;

    /* Message digest to use for key derivation */

    const EVP_MD *kdf_md;

    /* User key material */

    unsigned char *kdf_ukm;

    size_t kdf_ukmlen;

    /* KDF output length */

    size_t kdf_outlen;

} 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;

    dctx->cofactor_mode = -1;

    dctx->co_key = NULL;

    dctx->kdf_type = EVP_PKEY_ECDH_KDF_NONE;

    dctx->kdf_md = NULL;

    dctx->kdf_outlen = 0;

    dctx->kdf_ukm = NULL;

    dctx->kdf_ukmlen = 0;

    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;

    if (sctx->co_key) {

        dctx->co_key = EC_KEY_dup(sctx->co_key);

        if (!dctx->co_key)

            return 0;

    }

    dctx->kdf_type = sctx->kdf_type;

    dctx->kdf_md = sctx->kdf_md;

    dctx->kdf_outlen = sctx->kdf_outlen;

    if (sctx->kdf_ukm) {

        dctx->kdf_ukm = BUF_memdup(sctx->kdf_ukm, sctx->kdf_ukmlen);

        if (!dctx->kdf_ukm)

            return 0;

    } else

        dctx->kdf_ukm = NULL;

    dctx->kdf_ukmlen = sctx->kdf_ukmlen;

    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);

        if (dctx->co_key)

            EC_KEY_free(dctx->co_key);

        if (dctx->kdf_ukm)

            OPENSSL_free(dctx->kdf_ukm);

        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;

}

#ifndef OPENSSL_NO_ECDH

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;

    EC_KEY *eckey;

    EC_PKEY_CTX *dctx = ctx->data;

    if (!ctx->pkey || !ctx->peerkey) {

        ECerr(EC_F_PKEY_EC_DERIVE, EC_R_KEYS_NOT_SET);

        return 0;

    }

    eckey = dctx->co_key ? dctx->co_key : ctx->pkey->pkey.ec;

    if (!key) {

        const EC_GROUP *group;

        group = EC_KEY_get0_group(eckey);

        *keylen = (EC_GROUP_get_degree(group) + 7) / 8;

        return 1;

    }

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

    /*

     * NB: unlike PKCS#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, eckey, 0);

    if (ret <= 0)

        return 0;

    *keylen = ret;

    return 1;

}

static int pkey_ec_kdf_derive(EVP_PKEY_CTX *ctx,

                              unsigned char *key, size_t *keylen)

{

    EC_PKEY_CTX *dctx = ctx->data;

    unsigned char *ktmp = NULL;

    size_t ktmplen;

    int rv = 0;

    if (dctx->kdf_type == EVP_PKEY_ECDH_KDF_NONE)

        return pkey_ec_derive(ctx, key, keylen);

    if (!key) {

        *keylen = dctx->kdf_outlen;

        return 1;

    }

    if (*keylen != dctx->kdf_outlen)

        return 0;

    if (!pkey_ec_derive(ctx, NULL, &ktmplen))

        return 0;

    ktmp = OPENSSL_malloc(ktmplen);

    if (!ktmp)

        return 0;

    if (!pkey_ec_derive(ctx, ktmp, &ktmplen))

        goto err;

    /* Do KDF stuff */

    if (!ECDH_KDF_X9_62(key, *keylen, ktmp, ktmplen,

                        dctx->kdf_ukm, dctx->kdf_ukmlen, dctx->kdf_md))

        goto err;

    rv = 1;

 err:

    if (ktmp) {

        OPENSSL_cleanse(ktmp, ktmplen);

        OPENSSL_free(ktmp);

    }

    return rv;

}

#endif

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_EC_PARAM_ENC:

        if (!dctx->gen_group) {

            ECerr(EC_F_PKEY_EC_CTRL, EC_R_NO_PARAMETERS_SET);

            return 0;

        }

        EC_GROUP_set_asn1_flag(dctx->gen_group, p1);

        return 1;

#ifndef OPENSSL_NO_ECDH

    case EVP_PKEY_CTRL_EC_ECDH_COFACTOR:

        if (p1 == -2) {

            if (dctx->cofactor_mode != -1)

                return dctx->cofactor_mode;

            else {

                EC_KEY *ec_key = ctx->pkey->pkey.ec;

                return EC_KEY_get_flags(ec_key) & EC_FLAG_COFACTOR_ECDH ? 1 :

                    0;

            }

        } else if (p1 < -1 || p1 > 1)

            return -2;

        dctx->cofactor_mode = p1;

        if (p1 != -1) {

            EC_KEY *ec_key = ctx->pkey->pkey.ec;

            if (!ec_key->group)

                return -2;

            /* If cofactor is 1 cofactor mode does nothing */

            if (BN_is_one(&ec_key->group->cofactor))

                return 1;

            if (!dctx->co_key) {

                dctx->co_key = EC_KEY_dup(ec_key);

                if (!dctx->co_key)

                    return 0;

            }

            if (p1)

                EC_KEY_set_flags(dctx->co_key, EC_FLAG_COFACTOR_ECDH);

            else

                EC_KEY_clear_flags(dctx->co_key, EC_FLAG_COFACTOR_ECDH);

        } else if (dctx->co_key) {

            EC_KEY_free(dctx->co_key);

            dctx->co_key = NULL;

        }

        return 1;

#endif

    case EVP_PKEY_CTRL_EC_KDF_TYPE:

        if (p1 == -2)

            return dctx->kdf_type;

        if (p1 != EVP_PKEY_ECDH_KDF_NONE && p1 != EVP_PKEY_ECDH_KDF_X9_62)

            return -2;

        dctx->kdf_type = p1;

        return 1;

    case EVP_PKEY_CTRL_EC_KDF_MD:

        dctx->kdf_md = p2;

        return 1;

    case EVP_PKEY_CTRL_GET_EC_KDF_MD:

        *(const EVP_MD **)p2 = dctx->kdf_md;

        return 1;

    case EVP_PKEY_CTRL_EC_KDF_OUTLEN:

        if (p1 <= 0)

            return -2;

        dctx->kdf_outlen = (size_t)p1;

        return 1;

    case EVP_PKEY_CTRL_GET_EC_KDF_OUTLEN:

        *(int *)p2 = dctx->kdf_outlen;

        return 1;

    case EVP_PKEY_CTRL_EC_KDF_UKM:

        if (dctx->kdf_ukm)

            OPENSSL_free(dctx->kdf_ukm);

        dctx->kdf_ukm = p2;

        if (p2)

            dctx->kdf_ukmlen = p1;

        else

            dctx->kdf_ukmlen = 0;

        return 1;

    case EVP_PKEY_CTRL_GET_EC_KDF_UKM:

        *(unsigned char **)p2 = dctx->kdf_ukm;

        return dctx->kdf_ukmlen;

    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_GET_MD:

        *(const EVP_MD **)p2 = dctx->md;

        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 = EC_curve_nist2nid(value);

        if (nid == NID_undef)

            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);

    } else if (!strcmp(type, "ec_param_enc")) {

        int param_enc;

        if (!strcmp(value, "explicit"))

            param_enc = 0;

        else if (!strcmp(value, "named_curve"))

            param_enc = OPENSSL_EC_NAMED_CURVE;

        else

            return -2;

        return EVP_PKEY_CTX_set_ec_param_enc(ctx, param_enc);

    } else if (!strcmp(type, "ecdh_kdf_md")) {

        const EVP_MD *md;

        if (!(md = EVP_get_digestbyname(value))) {

            ECerr(EC_F_PKEY_EC_CTRL_STR, EC_R_INVALID_DIGEST);

            return 0;

        }

        return EVP_PKEY_CTX_set_ecdh_kdf_md(ctx, md);

    } else if (!strcmp(type, "ecdh_cofactor_mode")) {

        int co_mode;

        co_mode = atoi(value);

        return EVP_PKEY_CTX_set_ecdh_cofactor_mode(ctx, co_mode);

    }

    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;

    EC_PKEY_CTX *dctx = ctx->data;

    if (ctx->pkey == NULL && dctx->gen_group == 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);

    if (ctx->pkey) {

        /* Note: if error return, pkey is freed by parent routine */

        if (!EVP_PKEY_copy_parameters(pkey, ctx->pkey))

            return 0;

    } else {

        if (!EC_KEY_set_group(ec, dctx->gen_group))

            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,

#ifndef OPENSSL_NO_ECDH

    pkey_ec_kdf_derive,

#else

    0,

#endif

    pkey_ec_ctrl,

    pkey_ec_ctrl_str

};