webrtc/rtc_base/sslstreamadapter.cc

/*
 *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

#include "rtc_base/sslstreamadapter.h"

#include "rtc_base/opensslstreamadapter.h"

///////////////////////////////////////////////////////////////////////////////

namespace rtc {

// TODO(guoweis): Move this to SDP layer and use int form internally.
// webrtc:5043.
const char CS_AES_CM_128_HMAC_SHA1_80[] = "AES_CM_128_HMAC_SHA1_80";
const char CS_AES_CM_128_HMAC_SHA1_32[] = "AES_CM_128_HMAC_SHA1_32";
const char CS_AEAD_AES_128_GCM[] = "AEAD_AES_128_GCM";
const char CS_AEAD_AES_256_GCM[] = "AEAD_AES_256_GCM";

std::string SrtpCryptoSuiteToName(int crypto_suite) {
  switch (crypto_suite) {
    case SRTP_AES128_CM_SHA1_32:
      return CS_AES_CM_128_HMAC_SHA1_32;
    case SRTP_AES128_CM_SHA1_80:
      return CS_AES_CM_128_HMAC_SHA1_80;
    case SRTP_AEAD_AES_128_GCM:
      return CS_AEAD_AES_128_GCM;
    case SRTP_AEAD_AES_256_GCM:
      return CS_AEAD_AES_256_GCM;
    default:
      return std::string();
  }
}

int SrtpCryptoSuiteFromName(const std::string& crypto_suite) {
  if (crypto_suite == CS_AES_CM_128_HMAC_SHA1_32)
    return SRTP_AES128_CM_SHA1_32;
  if (crypto_suite == CS_AES_CM_128_HMAC_SHA1_80)
    return SRTP_AES128_CM_SHA1_80;
  if (crypto_suite == CS_AEAD_AES_128_GCM)
    return SRTP_AEAD_AES_128_GCM;
  if (crypto_suite == CS_AEAD_AES_256_GCM)
    return SRTP_AEAD_AES_256_GCM;
  return SRTP_INVALID_CRYPTO_SUITE;
}

bool GetSrtpKeyAndSaltLengths(int crypto_suite,
                              int* key_length,
                              int* salt_length) {
  switch (crypto_suite) {
    case SRTP_AES128_CM_SHA1_32:
    case SRTP_AES128_CM_SHA1_80:
      // SRTP_AES128_CM_HMAC_SHA1_32 and SRTP_AES128_CM_HMAC_SHA1_80 are defined
      // in RFC 5764 to use a 128 bits key and 112 bits salt for the cipher.
      *key_length = 16;
      *salt_length = 14;
      break;
    case SRTP_AEAD_AES_128_GCM:
      // SRTP_AEAD_AES_128_GCM is defined in RFC 7714 to use a 128 bits key and
      // a 96 bits salt for the cipher.
      *key_length = 16;
      *salt_length = 12;
      break;
    case SRTP_AEAD_AES_256_GCM:
      // SRTP_AEAD_AES_256_GCM is defined in RFC 7714 to use a 256 bits key and
      // a 96 bits salt for the cipher.
      *key_length = 32;
      *salt_length = 12;
      break;
    default:
      return false;
  }
  return true;
}

bool IsGcmCryptoSuite(int crypto_suite) {
  return (crypto_suite == SRTP_AEAD_AES_256_GCM ||
          crypto_suite == SRTP_AEAD_AES_128_GCM);
}

bool IsGcmCryptoSuiteName(const std::string& crypto_suite) {
  return (crypto_suite == CS_AEAD_AES_256_GCM ||
          crypto_suite == CS_AEAD_AES_128_GCM);
}

// static
CryptoOptions CryptoOptions::NoGcm() {
  CryptoOptions options;
  options.enable_gcm_crypto_suites = false;
  return options;
}

std::vector<int> GetSupportedDtlsSrtpCryptoSuites(
    const rtc::CryptoOptions& crypto_options) {
  std::vector<int> crypto_suites;
  if (crypto_options.enable_gcm_crypto_suites) {
    crypto_suites.push_back(rtc::SRTP_AEAD_AES_256_GCM);
    crypto_suites.push_back(rtc::SRTP_AEAD_AES_128_GCM);
  }
  // Note: SRTP_AES128_CM_SHA1_80 is what is required to be supported (by
  // draft-ietf-rtcweb-security-arch), but SRTP_AES128_CM_SHA1_32 is allowed as
  // well, and saves a few bytes per packet if it ends up selected.
  // As the cipher suite is potentially insecure, it will only be used if
  // enabled by both peers.
  if (crypto_options.enable_aes128_sha1_32_crypto_cipher) {
    crypto_suites.push_back(rtc::SRTP_AES128_CM_SHA1_32);
  }
  crypto_suites.push_back(rtc::SRTP_AES128_CM_SHA1_80);
  return crypto_suites;
}

SSLStreamAdapter* SSLStreamAdapter::Create(StreamInterface* stream) {
  return new OpenSSLStreamAdapter(stream);
}

SSLStreamAdapter::SSLStreamAdapter(StreamInterface* stream)
    : StreamAdapterInterface(stream),
      ignore_bad_cert_(false),
      client_auth_enabled_(true) {}

SSLStreamAdapter::~SSLStreamAdapter() {}

bool SSLStreamAdapter::GetSslCipherSuite(int* cipher_suite) {
  return false;
}

bool SSLStreamAdapter::ExportKeyingMaterial(const std::string& label,
                                            const uint8_t* context,
                                            size_t context_len,
                                            bool use_context,
                                            uint8_t* result,
                                            size_t result_len) {
  return false;  // Default is unsupported
}

bool SSLStreamAdapter::SetDtlsSrtpCryptoSuites(
    const std::vector<int>& crypto_suites) {
  return false;
}

bool SSLStreamAdapter::GetDtlsSrtpCryptoSuite(int* crypto_suite) {
  return false;
}

bool SSLStreamAdapter::IsBoringSsl() {
  return OpenSSLStreamAdapter::IsBoringSsl();
}
bool SSLStreamAdapter::IsAcceptableCipher(int cipher, KeyType key_type) {
  return OpenSSLStreamAdapter::IsAcceptableCipher(cipher, key_type);
}
bool SSLStreamAdapter::IsAcceptableCipher(const std::string& cipher,
                                          KeyType key_type) {
  return OpenSSLStreamAdapter::IsAcceptableCipher(cipher, key_type);
}
std::string SSLStreamAdapter::SslCipherSuiteToName(int cipher_suite) {
  return OpenSSLStreamAdapter::SslCipherSuiteToName(cipher_suite);
}
void SSLStreamAdapter::enable_time_callback_for_testing() {
  OpenSSLStreamAdapter::enable_time_callback_for_testing();
}

///////////////////////////////////////////////////////////////////////////////

}  // namespace rtc