src/ssl/t1_enc.cc

/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * 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 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 acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS 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 AUTHOR OR 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.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */
/* ====================================================================
 * 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).
 *
 */
/* ====================================================================
 * Copyright 2005 Nokia. All rights reserved.
 *
 * The portions of the attached software ("Contribution") is developed by
 * Nokia Corporation and is licensed pursuant to the OpenSSL open source
 * license.
 *
 * The Contribution, originally written by Mika Kousa and Pasi Eronen of
 * Nokia Corporation, consists of the "PSK" (Pre-Shared Key) ciphersuites
 * support (see RFC 4279) to OpenSSL.
 *
 * No patent licenses or other rights except those expressly stated in
 * the OpenSSL open source license shall be deemed granted or received
 * expressly, by implication, estoppel, or otherwise.
 *
 * No assurances are provided by Nokia that the Contribution does not
 * infringe the patent or other intellectual property rights of any third
 * party or that the license provides you with all the necessary rights
 * to make use of the Contribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. IN
 * ADDITION TO THE DISCLAIMERS INCLUDED IN THE LICENSE, NOKIA
 * SPECIFICALLY DISCLAIMS ANY LIABILITY FOR CLAIMS BROUGHT BY YOU OR ANY
 * OTHER ENTITY BASED ON INFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS OR
 * OTHERWISE. */

#include <openssl/ssl.h>

#include <assert.h>
#include <string.h>

#include <utility>

#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/hmac.h>
#include <openssl/md5.h>
#include <openssl/mem.h>
#include <openssl/nid.h>
#include <openssl/rand.h>

#include "../crypto/fipsmodule/tls/internal.h"
#include "../crypto/internal.h"
#include "internal.h"


BSSL_NAMESPACE_BEGIN

bool tls1_prf(const EVP_MD *digest, Span<uint8_t> out,
              Span<const uint8_t> secret, Span<const char> label,
              Span<const uint8_t> seed1, Span<const uint8_t> seed2) {
  return 1 == CRYPTO_tls1_prf(digest, out.data(), out.size(), secret.data(),
                              secret.size(), label.data(), label.size(),
                              seed1.data(), seed1.size(), seed2.data(),
                              seed2.size());
}

static bool get_key_block_lengths(const SSL *ssl, size_t *out_mac_secret_len,
                                  size_t *out_key_len, size_t *out_iv_len,
                                  const SSL_CIPHER *cipher) {
  const EVP_AEAD *aead = NULL;
  if (!ssl_cipher_get_evp_aead(&aead, out_mac_secret_len, out_iv_len, cipher,
                               ssl_protocol_version(ssl))) {
    OPENSSL_PUT_ERROR(SSL, SSL_R_CIPHER_OR_HASH_UNAVAILABLE);
    return false;
  }

  *out_key_len = EVP_AEAD_key_length(aead);
  if (*out_mac_secret_len > 0) {
    // For "stateful" AEADs (i.e. compatibility with pre-AEAD cipher suites) the
    // key length reported by |EVP_AEAD_key_length| will include the MAC key
    // bytes and initial implicit IV.
    if (*out_key_len < *out_mac_secret_len + *out_iv_len) {
      OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
      return false;
    }
    *out_key_len -= *out_mac_secret_len + *out_iv_len;
  }

  return true;
}

static bool generate_key_block(const SSL *ssl, Span<uint8_t> out,
                               const SSL_SESSION *session) {
  static const char kLabel[] = "key expansion";
  auto label = MakeConstSpan(kLabel, sizeof(kLabel) - 1);

  const EVP_MD *digest = ssl_session_get_digest(session);
  // Note this function assumes that |session|'s key material corresponds to
  // |ssl->s3->client_random| and |ssl->s3->server_random|.
  return tls1_prf(digest, out, session->secret, label, ssl->s3->server_random,
                  ssl->s3->client_random);
}

bool tls1_configure_aead(SSL *ssl, evp_aead_direction_t direction,
                         Array<uint8_t> *key_block_cache,
                         const SSL_SESSION *session,
                         Span<const uint8_t> iv_override) {
  size_t mac_secret_len, key_len, iv_len;
  if (!get_key_block_lengths(ssl, &mac_secret_len, &key_len, &iv_len,
                             session->cipher)) {
    return false;
  }

  // Ensure that |key_block_cache| is set up.
  const size_t key_block_size = 2 * (mac_secret_len + key_len + iv_len);
  if (key_block_cache->empty()) {
    if (!key_block_cache->InitForOverwrite(key_block_size) ||
        !generate_key_block(ssl, MakeSpan(*key_block_cache), session)) {
      return false;
    }
  }
  assert(key_block_cache->size() == key_block_size);

  Span<const uint8_t> key_block = *key_block_cache;
  Span<const uint8_t> mac_secret, key, iv;
  if (direction == (ssl->server ? evp_aead_open : evp_aead_seal)) {
    // Use the client write (server read) keys.
    mac_secret = key_block.subspan(0, mac_secret_len);
    key = key_block.subspan(2 * mac_secret_len, key_len);
    iv = key_block.subspan(2 * mac_secret_len + 2 * key_len, iv_len);
  } else {
    // Use the server write (client read) keys.
    mac_secret = key_block.subspan(mac_secret_len, mac_secret_len);
    key = key_block.subspan(2 * mac_secret_len + key_len, key_len);
    iv = key_block.subspan(2 * mac_secret_len + 2 * key_len + iv_len, iv_len);
  }

  if (!iv_override.empty()) {
    if (iv_override.size() != iv_len) {
      return false;
    }
    iv = iv_override;
  }

  UniquePtr<SSLAEADContext> aead_ctx = SSLAEADContext::Create(
      direction, ssl->s3->version, session->cipher, key, mac_secret, iv);
  if (!aead_ctx) {
    return false;
  }

  if (direction == evp_aead_open) {
    return ssl->method->set_read_state(ssl, ssl_encryption_application,
                                       std::move(aead_ctx),
                                       /*traffic_secret=*/{});
  }

  return ssl->method->set_write_state(ssl, ssl_encryption_application,
                                      std::move(aead_ctx),
                                      /*traffic_secret=*/{});
}

bool tls1_change_cipher_state(SSL_HANDSHAKE *hs,
                              evp_aead_direction_t direction) {
  return tls1_configure_aead(hs->ssl, direction, &hs->key_block,
                             ssl_handshake_session(hs), {});
}

bool tls1_generate_master_secret(SSL_HANDSHAKE *hs, Span<uint8_t> out,
                                 Span<const uint8_t> premaster) {
  static const char kMasterSecretLabel[] = "master secret";
  static const char kExtendedMasterSecretLabel[] = "extended master secret";
  BSSL_CHECK(out.size() == SSL3_MASTER_SECRET_SIZE);

  const SSL *ssl = hs->ssl;
  if (hs->extended_master_secret) {
    auto label = MakeConstSpan(kExtendedMasterSecretLabel,
                               sizeof(kExtendedMasterSecretLabel) - 1);
    uint8_t digests[EVP_MAX_MD_SIZE];
    size_t digests_len;
    if (!hs->transcript.GetHash(digests, &digests_len) ||
        !tls1_prf(hs->transcript.Digest(), out, premaster, label,
                  MakeConstSpan(digests, digests_len), {})) {
      return false;
    }
  } else {
    auto label =
        MakeConstSpan(kMasterSecretLabel, sizeof(kMasterSecretLabel) - 1);
    if (!tls1_prf(hs->transcript.Digest(), out, premaster, label,
                  ssl->s3->client_random, ssl->s3->server_random)) {
      return false;
    }
  }

  return true;
}

BSSL_NAMESPACE_END

using namespace bssl;

size_t SSL_get_key_block_len(const SSL *ssl) {
  // See |SSL_generate_key_block|.
  if (SSL_in_init(ssl) || ssl_protocol_version(ssl) > TLS1_2_VERSION) {
    return 0;
  }

  size_t mac_secret_len, key_len, fixed_iv_len;
  if (!get_key_block_lengths(ssl, &mac_secret_len, &key_len, &fixed_iv_len,
                             SSL_get_current_cipher(ssl))) {
    ERR_clear_error();
    return 0;
  }

  return 2 * (mac_secret_len + key_len + fixed_iv_len);
}

int SSL_generate_key_block(const SSL *ssl, uint8_t *out, size_t out_len) {
  // Which cipher state to use is ambiguous during a handshake. In particular,
  // there are points where read and write states are from different epochs.
  // During a handshake, before ChangeCipherSpec, the encryption states may not
  // match |ssl->s3->client_random| and |ssl->s3->server_random|.
  if (SSL_in_init(ssl) || ssl_protocol_version(ssl) > TLS1_2_VERSION) {
    OPENSSL_PUT_ERROR(SSL, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
    return 0;
  }

  return generate_key_block(ssl, MakeSpan(out, out_len), SSL_get_session(ssl));
}

int SSL_export_keying_material(SSL *ssl, uint8_t *out, size_t out_len,
                               const char *label, size_t label_len,
                               const uint8_t *context, size_t context_len,
                               int use_context) {
  // In TLS 1.3, the exporter may be used whenever the secret has been derived.
  if (ssl->s3->version != 0 && ssl_protocol_version(ssl) >= TLS1_3_VERSION) {
    if (ssl->s3->exporter_secret.empty()) {
      OPENSSL_PUT_ERROR(SSL, SSL_R_HANDSHAKE_NOT_COMPLETE);
      return 0;
    }
    if (!use_context) {
      context = nullptr;
      context_len = 0;
    }
    return tls13_export_keying_material(
        ssl, MakeSpan(out, out_len), ssl->s3->exporter_secret,
        MakeConstSpan(label, label_len), MakeConstSpan(context, context_len));
  }

  // Exporters may be used in False Start, where the handshake has progressed
  // enough. Otherwise, they may not be used during a handshake.
  if (SSL_in_init(ssl) && !SSL_in_false_start(ssl)) {
    OPENSSL_PUT_ERROR(SSL, SSL_R_HANDSHAKE_NOT_COMPLETE);
    return 0;
  }

  size_t seed_len = 2 * SSL3_RANDOM_SIZE;
  if (use_context) {
    if (context_len >= 1u << 16) {
      OPENSSL_PUT_ERROR(SSL, ERR_R_OVERFLOW);
      return 0;
    }
    seed_len += 2 + context_len;
  }
  Array<uint8_t> seed;
  if (!seed.InitForOverwrite(seed_len)) {
    return 0;
  }

  OPENSSL_memcpy(seed.data(), ssl->s3->client_random, SSL3_RANDOM_SIZE);
  OPENSSL_memcpy(seed.data() + SSL3_RANDOM_SIZE, ssl->s3->server_random,
                 SSL3_RANDOM_SIZE);
  if (use_context) {
    seed[2 * SSL3_RANDOM_SIZE] = static_cast<uint8_t>(context_len >> 8);
    seed[2 * SSL3_RANDOM_SIZE + 1] = static_cast<uint8_t>(context_len);
    OPENSSL_memcpy(seed.data() + 2 * SSL3_RANDOM_SIZE + 2, context,
                   context_len);
  }

  const SSL_SESSION *session = SSL_get_session(ssl);
  const EVP_MD *digest = ssl_session_get_digest(session);
  return tls1_prf(digest, MakeSpan(out, out_len), session->secret,
                  MakeConstSpan(label, label_len), seed, {});
}