// Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL project 2007.
// Copyright (c) 2007 The OpenSSL Project.  All rights reserved.
// SPDX-License-Identifier: Apache-2.0

#include <openssl/digest.h>
#include <openssl/evp.h>
#include <openssl/mem.h>

#include "../internal.h"
#include "internal.h"


static int hmac_size(OPENSSL_UNUSED const EVP_PKEY *pkey) {
  return EVP_MAX_MD_SIZE;
}

static void hmac_key_free(EVP_PKEY *pkey) {
  HMAC_KEY *key = pkey->pkey.ptr;
  if (key != NULL) {
    OPENSSL_free(key->key);
  }
  OPENSSL_free(key);
}

static int hmac_set_key(EVP_PKEY *pkey, const uint8_t *priv, size_t len,
                        OPENSSL_UNUSED const uint8_t *pubkey,
                        OPENSSL_UNUSED size_t pubkey_len) {
  if (pkey->pkey.ptr != NULL) {
    return 0;
  }

  HMAC_KEY *key = HMAC_KEY_new();
  if (key == NULL) {
    return 0;
  }

  key->key = OPENSSL_memdup(priv, len);
  if (key->key == NULL && len > 0) {
    OPENSSL_free(key);
    return 0;
  }
  key->key_len = len;
  pkey->pkey.ptr = key;
  return 1;
}

static int hmac_get_key(const EVP_PKEY *pkey, uint8_t *priv, size_t *len) {
  HMAC_KEY *key = pkey->pkey.ptr;
  if (key == NULL || len == NULL) {
    return 0;
  }

  // The semantics of the EVP APIs are to return the length, if |priv| is NULL.
  if (priv == NULL) {
    *len = key->key_len;
    return 1;
  }

  // Retrieve the key, if |*len| has a large enough length.
  if (*len < key->key_len) {
    return 0;
  }
  *len = key->key_len;
  OPENSSL_memcpy(priv, key->key, key->key_len);
  return 1;
}


const EVP_PKEY_ASN1_METHOD hmac_asn1_meth = {
    EVP_PKEY_HMAC,
    {0xff} /* placeholder oid */,
    0 /* oid_len */,

    "HMAC",
    "OpenSSL HMAC method",

    NULL /* pub_decode */,
    NULL /* pub_encode */,
    NULL /* pub_cmp */,
    NULL /*priv_decode */,
    NULL /* priv_encode */,
    NULL /* priv_encode_v2 */,
    hmac_set_key /* set_priv_raw */,
    NULL /* set_pub_raw */,
    hmac_get_key /* get_priv_raw */,
    NULL /* get_pub_raw */,
    NULL /* pkey_opaque */,
    hmac_size /* pkey_size */,
    NULL /* pkey_bits */,
    NULL /* param_missing */,
    NULL /* param_copy */,
    NULL /* param_cmp */,
    hmac_key_free /* pkey_free */
};
