/* ====================================================================

 * Copyright (c) 1998-2007 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

 *    openssl-core@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 <assert.h>

#include <openssl/bytestring.h>

#include <openssl/digest.h>

#include <openssl/hkdf.h>

#include <openssl/hmac.h>

#include <openssl/mem.h>

#include "internal.h"

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

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

// tls1_P_hash computes the TLS P_<hash> function as described in RFC 5246,

// section 5. It XORs |out_len| bytes to |out|, using |md| as the hash and

// |secret| as the secret. |label|, |seed1|, and |seed2| are concatenated to

// form the seed parameter. It returns true on success and false on failure.

static int tls1_P_hash(uint8_t *out, size_t out_len,

                       const EVP_MD *md,

                       const uint8_t *secret, size_t secret_len,

                       const char *label, size_t label_len,

                       const uint8_t *seed1, size_t seed1_len,

                       const uint8_t *seed2, size_t seed2_len) {

  HMAC_CTX ctx, ctx_tmp, ctx_init;

  uint8_t A1[EVP_MAX_MD_SIZE];

  unsigned A1_len;

  int ret = 0;

  const size_t chunk = EVP_MD_size(md);

  HMAC_CTX_init(&ctx);

  HMAC_CTX_init(&ctx_tmp);

  HMAC_CTX_init(&ctx_init);

  if (!HMAC_Init_ex(&ctx_init, secret, secret_len, md, NULL) ||

      !HMAC_CTX_copy_ex(&ctx, &ctx_init) ||

      !HMAC_Update(&ctx, (const uint8_t *) label, label_len) ||

      !HMAC_Update(&ctx, seed1, seed1_len) ||

      !HMAC_Update(&ctx, seed2, seed2_len) ||

      !HMAC_Final(&ctx, A1, &A1_len)) {

    goto err;

  }

  for (;;) {

    unsigned len_u;

    uint8_t hmac[EVP_MAX_MD_SIZE];

    if (!HMAC_CTX_copy_ex(&ctx, &ctx_init) ||

        !HMAC_Update(&ctx, A1, A1_len) ||

        // Save a copy of |ctx| to compute the next A1 value below.

        (out_len > chunk && !HMAC_CTX_copy_ex(&ctx_tmp, &ctx)) ||

        !HMAC_Update(&ctx, (const uint8_t *) label, label_len) ||

        !HMAC_Update(&ctx, seed1, seed1_len) ||

        !HMAC_Update(&ctx, seed2, seed2_len) ||

        !HMAC_Final(&ctx, hmac, &len_u)) {

      goto err;

    }

    size_t len = len_u;

    assert(len == chunk);

    // XOR the result into |out|.

    if (len > out_len) {

      len = out_len;

    }

    for (size_t i = 0; i < len; i++) {

      out[i] ^= hmac[i];

    }

    out += len;

    out_len -= len;

    if (out_len == 0) {

      break;

    }

    // Calculate the next A1 value.

    if (!HMAC_Final(&ctx_tmp, A1, &A1_len)) {

      goto err;

    }

  }

  ret = 1;

err:

  OPENSSL_cleanse(A1, sizeof(A1));

  HMAC_CTX_cleanup(&ctx);

  HMAC_CTX_cleanup(&ctx_tmp);

  HMAC_CTX_cleanup(&ctx_init);

  return ret;

}

int CRYPTO_tls1_prf(const EVP_MD *digest,

                    uint8_t *out, size_t out_len,

                    const uint8_t *secret, size_t secret_len,

                    const char *label, size_t label_len,

                    const uint8_t *seed1, size_t seed1_len,

                    const uint8_t *seed2, size_t seed2_len) {

  if (out_len == 0) {

    return 1;

  }

  OPENSSL_memset(out, 0, out_len);

  const EVP_MD *const original_digest = digest;

  FIPS_service_indicator_lock_state();

  int ret = 0;

  if (digest == EVP_md5_sha1()) {

    // If using the MD5/SHA1 PRF, |secret| is partitioned between MD5 and SHA-1.

    size_t secret_half = secret_len - (secret_len / 2);

    if (!tls1_P_hash(out, out_len, EVP_md5(), secret, secret_half, label,

                     label_len, seed1, seed1_len, seed2, seed2_len)) {

      goto end;

    }

    // Note that, if |secret_len| is odd, the two halves share a byte.

    secret += secret_len - secret_half;

    secret_len = secret_half;

    digest = EVP_sha1();

  }

  ret = tls1_P_hash(out, out_len, digest, secret, secret_len, label, label_len,

                    seed1, seed1_len, seed2, seed2_len);

end:

  FIPS_service_indicator_unlock_state();

  if (ret) {

    TLSKDF_verify_service_indicator(original_digest);

  }

  return ret;

}

int CRYPTO_tls13_hkdf_expand_label(uint8_t *out, size_t out_len,

                                   const EVP_MD *digest,  //

                                   const uint8_t *secret, size_t secret_len,

                                   const uint8_t *label, size_t label_len,

                                   const uint8_t *hash, size_t hash_len) {

  static const uint8_t kProtocolLabel[] = "tls13 ";

  CBB cbb, child;

  uint8_t *hkdf_label = NULL;

  size_t hkdf_label_len;

  FIPS_service_indicator_lock_state();

  CBB_zero(&cbb);

  if (!CBB_init(&cbb, 2 + 1 + sizeof(kProtocolLabel) - 1 + label_len + 1 +

                          hash_len) ||

      !CBB_add_u16(&cbb, out_len) ||

      !CBB_add_u8_length_prefixed(&cbb, &child) ||

      !CBB_add_bytes(&child, kProtocolLabel, sizeof(kProtocolLabel) - 1) ||

      !CBB_add_bytes(&child, label, label_len) ||

      !CBB_add_u8_length_prefixed(&cbb, &child) ||

      !CBB_add_bytes(&child, hash, hash_len) ||

      !CBB_finish(&cbb, &hkdf_label, &hkdf_label_len)) {

    CBB_cleanup(&cbb);

    FIPS_service_indicator_unlock_state();

    return 0;

  }

  const int ret = HKDF_expand(out, out_len, digest, secret, secret_len,

                              hkdf_label, hkdf_label_len);

  OPENSSL_free(hkdf_label);

  FIPS_service_indicator_unlock_state();

  if (ret) {

    TLSKDF_verify_service_indicator(digest);

  }

  return ret;

}