/*

 * 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 <stdbool.h>

#include <stdio.h>

#include <openssl/err.h>

#include <openssl/opensslv.h>

#include <isc/crypto.h>

#include <isc/iterated_hash.h>

#include <isc/thread.h>

#include <isc/util.h>

#if OPENSSL_VERSION_NUMBER < 0x30000000L

#include <openssl/sha.h>

int

isc_iterated_hash(unsigned char *out, const unsigned int hashalg,

      const int iterations, const unsigned char *salt,

      const int saltlength, const unsigned char *in,

      const int inlength) {

  REQUIRE(out != NULL);

  int n = 0;

  size_t len;

  const unsigned char *buf;

  SHA_CTX ctx;

  if (hashalg != 1) {

    return 0;

  }

  buf = in;

  len = inlength;

  do {

    if (SHA1_Init(&ctx) != 1) {

      ERR_clear_error();

      return 0;

    }

    if (SHA1_Update(&ctx, buf, len) != 1) {

      ERR_clear_error();

      return 0;

    }

    if (SHA1_Update(&ctx, salt, saltlength) != 1) {

      ERR_clear_error();

      return 0;

    }

    if (SHA1_Final(out, &ctx) != 1) {

      ERR_clear_error();

      return 0;

    }

    buf = out;

    len = SHA_DIGEST_LENGTH;

  } while (n++ < iterations);

  return SHA_DIGEST_LENGTH;

}

void

isc__iterated_hash_initialize(void) {

  /* empty */

}

void

isc__iterated_hash_shutdown(void) {

  /* empty */

}

#else /* HAVE_SHA1_INIT */

#include <openssl/evp.h>

static thread_local bool initialized = false;

static thread_local EVP_MD_CTX *mdctx = NULL;

static thread_local EVP_MD_CTX *basectx = NULL;

int

isc_iterated_hash(unsigned char *out, const unsigned int hashalg,

      const int iterations, const unsigned char *salt,

      const int saltlength, const unsigned char *in,

      const int inlength) {

  REQUIRE(out != NULL);

  REQUIRE(mdctx != NULL);

  REQUIRE(basectx != NULL);

  int n = 0;

  size_t len;

  unsigned int outlength = 0;

  const unsigned char *buf;

  if (hashalg != 1) {

    return 0;

  }

  buf = in;

  len = inlength;

  do {

    if (EVP_MD_CTX_copy_ex(mdctx, basectx) != 1) {

      goto fail;

    }

    if (EVP_DigestUpdate(mdctx, buf, len) != 1) {

      goto fail;

    }

    if (EVP_DigestUpdate(mdctx, salt, saltlength) != 1) {

      goto fail;

    }

    if (EVP_DigestFinal_ex(mdctx, out, &outlength) != 1) {

      goto fail;

    }

    buf = out;

    len = outlength;

  } while (n++ < iterations);

  return outlength;

fail:

  ERR_clear_error();

  return 0;

}

void

isc__iterated_hash_initialize(void) {

  if (initialized) {

    return;

  }

  basectx = EVP_MD_CTX_new();

  INSIST(basectx != NULL);

  mdctx = EVP_MD_CTX_new();

  INSIST(mdctx != NULL);

  RUNTIME_CHECK(EVP_DigestInit_ex(basectx, isc__crypto_sha1, NULL) == 1);

  initialized = true;

}

void

isc__iterated_hash_shutdown(void) {

  if (!initialized) {

    return;

  }

  REQUIRE(mdctx != NULL);

  EVP_MD_CTX_free(mdctx);

  mdctx = NULL;

  REQUIRE(basectx != NULL);

  EVP_MD_CTX_free(basectx);

  basectx = NULL;

  initialized = false;

}

#endif /* HAVE_SHA1_INIT */