/* 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 <openssl/evp.h>

#include <openssl/bn.h>

#include <openssl/bytestring.h>

#include <openssl/ec.h>

#include <openssl/ec_key.h>

#include <openssl/ecdsa.h>

#include <openssl/err.h>

#include "internal.h"

static int eckey_pub_encode(CBB *out, const EVP_PKEY *key) {

  const EC_KEY *ec_key = key->pkey;

  const EC_GROUP *group = EC_KEY_get0_group(ec_key);

  const EC_POINT *public_key = EC_KEY_get0_public_key(ec_key);

  // See RFC 5480, section 2.

  CBB spki, algorithm, oid, key_bitstring;

  if (!CBB_add_asn1(out, &spki, CBS_ASN1_SEQUENCE) ||

      !CBB_add_asn1(&spki, &algorithm, CBS_ASN1_SEQUENCE) ||

      !CBB_add_asn1(&algorithm, &oid, CBS_ASN1_OBJECT) ||

      !CBB_add_bytes(&oid, ec_asn1_meth.oid, ec_asn1_meth.oid_len) ||

      !EC_KEY_marshal_curve_name(&algorithm, group) ||

      !CBB_add_asn1(&spki, &key_bitstring, CBS_ASN1_BITSTRING) ||

      !CBB_add_u8(&key_bitstring, 0 /* padding */) ||

      !EC_POINT_point2cbb(&key_bitstring, group, public_key,

                          POINT_CONVERSION_UNCOMPRESSED, NULL) ||

      !CBB_flush(out)) {

    OPENSSL_PUT_ERROR(EVP, EVP_R_ENCODE_ERROR);

    return 0;

  }

  return 1;

}

static int eckey_pub_decode(EVP_PKEY *out, CBS *params, CBS *key) {

  // See RFC 5480, section 2.

  // The parameters are a named curve.

  EC_KEY *eckey = NULL;

  const EC_GROUP *group = EC_KEY_parse_curve_name(params);

  if (group == NULL || CBS_len(params) != 0) {

    OPENSSL_PUT_ERROR(EVP, EVP_R_DECODE_ERROR);

    goto err;

  }

  eckey = EC_KEY_new();

  if (eckey == NULL || //

      !EC_KEY_set_group(eckey, group) ||

      !EC_KEY_oct2key(eckey, CBS_data(key), CBS_len(key), NULL)) {

    goto err;

  }

  EVP_PKEY_assign_EC_KEY(out, eckey);

  return 1;

err:

  EC_KEY_free(eckey);

  return 0;

}

static int eckey_pub_cmp(const EVP_PKEY *a, const EVP_PKEY *b) {

  const EC_KEY *a_ec = a->pkey;

  const EC_KEY *b_ec = b->pkey;

  const EC_GROUP *group = EC_KEY_get0_group(b_ec);

  const EC_POINT *pa = EC_KEY_get0_public_key(a_ec),

                 *pb = EC_KEY_get0_public_key(b_ec);

  int r = EC_POINT_cmp(group, pa, pb, NULL);

  if (r == 0) {

    return 1;

  } else if (r == 1) {

    return 0;

  } else {

    return -2;

  }

}

static int eckey_priv_decode(EVP_PKEY *out, CBS *params, CBS *key) {

  // See RFC 5915.

  const EC_GROUP *group = EC_KEY_parse_parameters(params);

  if (group == NULL || CBS_len(params) != 0) {

    OPENSSL_PUT_ERROR(EVP, EVP_R_DECODE_ERROR);

    return 0;

  }

  EC_KEY *ec_key = EC_KEY_parse_private_key(key, group);

  if (ec_key == NULL || CBS_len(key) != 0) {

    OPENSSL_PUT_ERROR(EVP, EVP_R_DECODE_ERROR);

    EC_KEY_free(ec_key);

    return 0;

  }

  EVP_PKEY_assign_EC_KEY(out, ec_key);

  return 1;

}

static int eckey_priv_encode(CBB *out, const EVP_PKEY *key) {

  const EC_KEY *ec_key = key->pkey;

  // Omit the redundant copy of the curve name. This contradicts RFC 5915 but

  // aligns with PKCS #11. SEC 1 only says they may be omitted if known by other

  // means. Both OpenSSL and NSS omit the redundant parameters, so we omit them

  // as well.

  unsigned enc_flags = EC_KEY_get_enc_flags(ec_key) | EC_PKEY_NO_PARAMETERS;

  // See RFC 5915.

  CBB pkcs8, algorithm, oid, private_key;

  if (!CBB_add_asn1(out, &pkcs8, CBS_ASN1_SEQUENCE) ||

      !CBB_add_asn1_uint64(&pkcs8, 0 /* version */) ||

      !CBB_add_asn1(&pkcs8, &algorithm, CBS_ASN1_SEQUENCE) ||

      !CBB_add_asn1(&algorithm, &oid, CBS_ASN1_OBJECT) ||

      !CBB_add_bytes(&oid, ec_asn1_meth.oid, ec_asn1_meth.oid_len) ||

      !EC_KEY_marshal_curve_name(&algorithm, EC_KEY_get0_group(ec_key)) ||

      !CBB_add_asn1(&pkcs8, &private_key, CBS_ASN1_OCTETSTRING) ||

      !EC_KEY_marshal_private_key(&private_key, ec_key, enc_flags) ||

      !CBB_flush(out)) {

    OPENSSL_PUT_ERROR(EVP, EVP_R_ENCODE_ERROR);

    return 0;

  }

  return 1;

}

static int eckey_set1_tls_encodedpoint(EVP_PKEY *pkey, const uint8_t *in,

                                       size_t len) {

  EC_KEY *ec_key = pkey->pkey;

  if (ec_key == NULL) {

    OPENSSL_PUT_ERROR(EVP, EVP_R_NO_KEY_SET);

    return 0;

  }

  return EC_KEY_oct2key(ec_key, in, len, NULL);

}

static size_t eckey_get1_tls_encodedpoint(const EVP_PKEY *pkey,

                                          uint8_t **out_ptr) {

  const EC_KEY *ec_key = pkey->pkey;

  if (ec_key == NULL) {

    OPENSSL_PUT_ERROR(EVP, EVP_R_NO_KEY_SET);

    return 0;

  }

  return EC_KEY_key2buf(ec_key, POINT_CONVERSION_UNCOMPRESSED, out_ptr, NULL);

}

static int int_ec_size(const EVP_PKEY *pkey) {

  const EC_KEY *ec_key = pkey->pkey;

  return ECDSA_size(ec_key);

}

static int ec_bits(const EVP_PKEY *pkey) {

  const EC_KEY *ec_key = pkey->pkey;

  const EC_GROUP *group = EC_KEY_get0_group(ec_key);

  if (group == NULL) {

    ERR_clear_error();

    return 0;

  }

  return EC_GROUP_order_bits(group);

}

static int ec_missing_parameters(const EVP_PKEY *pkey) {

  const EC_KEY *ec_key = pkey->pkey;

  return ec_key == NULL || EC_KEY_get0_group(ec_key) == NULL;

}

static int ec_copy_parameters(EVP_PKEY *to, const EVP_PKEY *from) {

  const EC_KEY *from_key = from->pkey;

  if (from_key == NULL) {

    OPENSSL_PUT_ERROR(EVP, EVP_R_NO_KEY_SET);

    return 0;

  }

  const EC_GROUP *group = EC_KEY_get0_group(from_key);

  if (group == NULL) {

    OPENSSL_PUT_ERROR(EVP, EVP_R_MISSING_PARAMETERS);

    return 0;

  }

  if (to->pkey == NULL) {

    to->pkey = EC_KEY_new();

    if (to->pkey == NULL) {

      return 0;

    }

  }

  return EC_KEY_set_group(to->pkey, group);

}

static int ec_cmp_parameters(const EVP_PKEY *a, const EVP_PKEY *b) {

  const EC_KEY *a_ec = a->pkey;

  const EC_KEY *b_ec = b->pkey;

  if (a_ec == NULL || b_ec == NULL) {

    return -2;

  }

  const EC_GROUP *group_a = EC_KEY_get0_group(a_ec),

                 *group_b = EC_KEY_get0_group(b_ec);

  if (group_a == NULL || group_b == NULL) {

    return -2;

  }

  if (EC_GROUP_cmp(group_a, group_b, NULL) != 0) {

    // mismatch

    return 0;

  }

  return 1;

}

static void int_ec_free(EVP_PKEY *pkey) {

  EC_KEY_free(pkey->pkey);

  pkey->pkey = NULL;

}

static int eckey_opaque(const EVP_PKEY *pkey) {

  const EC_KEY *ec_key = pkey->pkey;

  return EC_KEY_is_opaque(ec_key);

}

const EVP_PKEY_ASN1_METHOD ec_asn1_meth = {

    EVP_PKEY_EC,

    // 1.2.840.10045.2.1

    {0x2a, 0x86, 0x48, 0xce, 0x3d, 0x02, 0x01},

    7,

    &ec_pkey_meth,

    eckey_pub_decode,

    eckey_pub_encode,

    eckey_pub_cmp,

    eckey_priv_decode,

    eckey_priv_encode,

    /*set_priv_raw=*/NULL,

    /*set_pub_raw=*/NULL,

    /*get_priv_raw=*/NULL,

    /*get_pub_raw=*/NULL,

    eckey_set1_tls_encodedpoint,

    eckey_get1_tls_encodedpoint,

    eckey_opaque,

    int_ec_size,

    ec_bits,

    ec_missing_parameters,

    ec_copy_parameters,

    ec_cmp_parameters,

    int_ec_free,

};

int EVP_PKEY_set1_EC_KEY(EVP_PKEY *pkey, EC_KEY *key) {

  if (EVP_PKEY_assign_EC_KEY(pkey, key)) {

    EC_KEY_up_ref(key);

    return 1;

  }

  return 0;

}

int EVP_PKEY_assign_EC_KEY(EVP_PKEY *pkey, EC_KEY *key) {

  evp_pkey_set_method(pkey, &ec_asn1_meth);

  pkey->pkey = key;

  return key != NULL;

}

EC_KEY *EVP_PKEY_get0_EC_KEY(const EVP_PKEY *pkey) {

  if (pkey->type != EVP_PKEY_EC) {

    OPENSSL_PUT_ERROR(EVP, EVP_R_EXPECTING_AN_EC_KEY_KEY);

    return NULL;

  }

  return pkey->pkey;

}

EC_KEY *EVP_PKEY_get1_EC_KEY(const EVP_PKEY *pkey) {

  EC_KEY *ec_key = EVP_PKEY_get0_EC_KEY(pkey);

  if (ec_key != NULL) {

    EC_KEY_up_ref(ec_key);

  }

  return ec_key;

}