/*

 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")

 *

 * SPDX-License-Identifier: MPL-2.0

 *

 * This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, you can obtain one at https://mozilla.org/MPL/2.0/.

 *

 * See the COPYRIGHT file distributed with this work for additional

 * information regarding copyright ownership.

 */

#include <openssl/err.h>

#include <openssl/evp.h>

#include <openssl/opensslv.h>

#include <isc/assertions.h>

#include <isc/hmac.h>

#include <isc/md.h>

#include <isc/safe.h>

#include <isc/string.h>

#include <isc/types.h>

#include <isc/util.h>

#include "openssl_shim.h"

isc_hmac_t *

isc_hmac_new(void) {

  EVP_MD_CTX *hmac_st = EVP_MD_CTX_new();

  RUNTIME_CHECK(hmac_st != NULL);

  return (isc_hmac_t *)hmac_st;

}

void

isc_hmac_free(isc_hmac_t *hmac_st) {

  if (hmac_st == NULL) {

    return;

  }

  EVP_MD_CTX_free((EVP_MD_CTX *)hmac_st);

}

isc_result_t

isc_hmac_init(isc_hmac_t *hmac_st, const void *key, const size_t keylen,

        const isc_md_type_t *md_type) {

  EVP_PKEY *pkey;

  REQUIRE(hmac_st != NULL);

  REQUIRE(key != NULL);

  REQUIRE(keylen <= INT_MAX);

  if (md_type == NULL) {

    return ISC_R_NOTIMPLEMENTED;

  }

  pkey = EVP_PKEY_new_raw_private_key(EVP_PKEY_HMAC, NULL, key, keylen);

  if (pkey == NULL) {

    ERR_clear_error();

    return ISC_R_CRYPTOFAILURE;

  }

  if (EVP_DigestSignInit(hmac_st, NULL, md_type, NULL, pkey) != 1) {

    EVP_PKEY_free(pkey);

    ERR_clear_error();

    return ISC_R_CRYPTOFAILURE;

  }

  EVP_PKEY_free(pkey);

  return ISC_R_SUCCESS;

}

isc_result_t

isc_hmac_reset(isc_hmac_t *hmac_st) {

  REQUIRE(hmac_st != NULL);

  if (EVP_MD_CTX_reset(hmac_st) != 1) {

    ERR_clear_error();

    return ISC_R_CRYPTOFAILURE;

  }

  return ISC_R_SUCCESS;

}

isc_result_t

isc_hmac_update(isc_hmac_t *hmac_st, const unsigned char *buf,

    const size_t len) {

  REQUIRE(hmac_st != NULL);

  if (buf == NULL || len == 0) {

    return ISC_R_SUCCESS;

  }

  if (EVP_DigestSignUpdate(hmac_st, buf, len) != 1) {

    ERR_clear_error();

    return ISC_R_CRYPTOFAILURE;

  }

  return ISC_R_SUCCESS;

}

isc_result_t

isc_hmac_final(isc_hmac_t *hmac_st, unsigned char *digest,

         unsigned int *digestlen) {

  REQUIRE(hmac_st != NULL);

  REQUIRE(digest != NULL);

  REQUIRE(digestlen != NULL);

  size_t len = *digestlen;

  if (EVP_DigestSignFinal(hmac_st, digest, &len) != 1) {

    ERR_clear_error();

    return ISC_R_CRYPTOFAILURE;

  }

  *digestlen = (unsigned int)len;

  return ISC_R_SUCCESS;

}

const isc_md_type_t *

isc_hmac_get_md_type(isc_hmac_t *hmac_st) {

  REQUIRE(hmac_st != NULL);

  return EVP_MD_CTX_get0_md(hmac_st);

}

size_t

isc_hmac_get_size(isc_hmac_t *hmac_st) {

  REQUIRE(hmac_st != NULL);

  return (size_t)EVP_MD_CTX_size(hmac_st);

}

int

isc_hmac_get_block_size(isc_hmac_t *hmac_st) {

  REQUIRE(hmac_st != NULL);

  return EVP_MD_CTX_block_size(hmac_st);

}

isc_result_t

isc_hmac(const isc_md_type_t *type, const void *key, const size_t keylen,

   const unsigned char *buf, const size_t len, unsigned char *digest,

   unsigned int *digestlen) {

  isc_result_t res;

  isc_hmac_t *hmac_st = isc_hmac_new();

  res = isc_hmac_init(hmac_st, key, keylen, type);

  if (res != ISC_R_SUCCESS) {

    goto end;

  }

  res = isc_hmac_update(hmac_st, buf, len);

  if (res != ISC_R_SUCCESS) {

    goto end;

  }

  res = isc_hmac_final(hmac_st, digest, digestlen);

  if (res != ISC_R_SUCCESS) {

    goto end;

  }

end:

  isc_hmac_free(hmac_st);

  return res;

}