net/quic/quic_crypto_server_stream.cc

// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "net/quic/quic_crypto_server_stream.h"

#include "base/base64.h"
#include "crypto/secure_hash.h"
#include "net/quic/crypto/crypto_protocol.h"
#include "net/quic/crypto/crypto_utils.h"
#include "net/quic/crypto/quic_crypto_server_config.h"
#include "net/quic/crypto/source_address_token.h"
#include "net/quic/quic_config.h"
#include "net/quic/quic_flags.h"
#include "net/quic/quic_protocol.h"
#include "net/quic/quic_session.h"

namespace net {

void ServerHelloNotifier::OnAckNotification(
    int num_original_packets,
    int num_original_bytes,
    int num_retransmitted_packets,
    int num_retransmitted_bytes,
    QuicTime::Delta delta_largest_observed) {
  server_stream_->OnServerHelloAcked();
}

QuicCryptoServerStream::QuicCryptoServerStream(
    const QuicCryptoServerConfig& crypto_config,
    QuicSession* session)
    : QuicCryptoStream(session),
      crypto_config_(crypto_config),
      validate_client_hello_cb_(nullptr),
      num_handshake_messages_(0),
      num_server_config_update_messages_sent_(0) {}

QuicCryptoServerStream::~QuicCryptoServerStream() {
  CancelOutstandingCallbacks();
}

void QuicCryptoServerStream::CancelOutstandingCallbacks() {
  // Detach from the validation callback.  Calling this multiple times is safe.
  if (validate_client_hello_cb_ != nullptr) {
    validate_client_hello_cb_->Cancel();
  }
}

void QuicCryptoServerStream::OnHandshakeMessage(
    const CryptoHandshakeMessage& message) {
  QuicCryptoStream::OnHandshakeMessage(message);
  ++num_handshake_messages_;

  // Do not process handshake messages after the handshake is confirmed.
  if (handshake_confirmed_) {
    CloseConnection(QUIC_CRYPTO_MESSAGE_AFTER_HANDSHAKE_COMPLETE);
    return;
  }

  if (message.tag() != kCHLO) {
    CloseConnection(QUIC_INVALID_CRYPTO_MESSAGE_TYPE);
    return;
  }

  if (validate_client_hello_cb_ != nullptr) {
    // Already processing some other handshake message.  The protocol
    // does not allow for clients to send multiple handshake messages
    // before the server has a chance to respond.
    CloseConnection(QUIC_CRYPTO_MESSAGE_WHILE_VALIDATING_CLIENT_HELLO);
    return;
  }

  validate_client_hello_cb_ = new ValidateCallback(this);
  return crypto_config_.ValidateClientHello(
      message,
      session()->connection()->peer_address(),
      session()->connection()->clock(),
      validate_client_hello_cb_);
}

void QuicCryptoServerStream::FinishProcessingHandshakeMessage(
    const CryptoHandshakeMessage& message,
    const ValidateClientHelloResultCallback::Result& result) {
  // Clear the callback that got us here.
  DCHECK(validate_client_hello_cb_ != nullptr);
  validate_client_hello_cb_ = nullptr;

  string error_details;
  CryptoHandshakeMessage reply;
  QuicErrorCode error = ProcessClientHello(
      message, result, &reply, &error_details);

  if (error != QUIC_NO_ERROR) {
    CloseConnectionWithDetails(error, error_details);
    return;
  }

  if (reply.tag() != kSHLO) {
    SendHandshakeMessage(reply);
    return;
  }

  // If we are returning a SHLO then we accepted the handshake.
  QuicConfig* config = session()->config();
  OverrideQuicConfigDefaults(config);
  error = config->ProcessPeerHello(message, CLIENT, &error_details);
  if (error != QUIC_NO_ERROR) {
    CloseConnectionWithDetails(error, error_details);
    return;
  }
  session()->OnConfigNegotiated();

  config->ToHandshakeMessage(&reply);

  // Receiving a full CHLO implies the client is prepared to decrypt with
  // the new server write key.  We can start to encrypt with the new server
  // write key.
  //
  // NOTE: the SHLO will be encrypted with the new server write key.
  session()->connection()->SetEncrypter(
      ENCRYPTION_INITIAL,
      crypto_negotiated_params_.initial_crypters.encrypter.release());
  session()->connection()->SetDefaultEncryptionLevel(
      ENCRYPTION_INITIAL);
  // Set the decrypter immediately so that we no longer accept unencrypted
  // packets.
  session()->connection()->SetDecrypter(
      crypto_negotiated_params_.initial_crypters.decrypter.release(),
      ENCRYPTION_INITIAL);

  // We want to be notified when the SHLO is ACKed so that we can disable
  // HANDSHAKE_MODE in the sent packet manager.
  if (session()->connection()->version() <= QUIC_VERSION_21) {
    SendHandshakeMessage(reply);
  } else {
    scoped_refptr<ServerHelloNotifier> server_hello_notifier(
        new ServerHelloNotifier(this));
    SendHandshakeMessage(reply, server_hello_notifier.get());
  }

  session()->connection()->SetEncrypter(
      ENCRYPTION_FORWARD_SECURE,
      crypto_negotiated_params_.forward_secure_crypters.encrypter.release());
  session()->connection()->SetDefaultEncryptionLevel(
      ENCRYPTION_FORWARD_SECURE);
  session()->connection()->SetAlternativeDecrypter(
      crypto_negotiated_params_.forward_secure_crypters.decrypter.release(),
      ENCRYPTION_FORWARD_SECURE, false /* don't latch */);

  encryption_established_ = true;
  handshake_confirmed_ = true;
  session()->OnCryptoHandshakeEvent(QuicSession::HANDSHAKE_CONFIRMED);

  // Now that the handshake is complete, send an updated server config and
  // source-address token to the client.
  SendServerConfigUpdate(previous_cached_network_params_.get(), true);
}

void QuicCryptoServerStream::SendServerConfigUpdate(
    const CachedNetworkParameters* cached_network_params,
    bool on_handshake_complete) {
  if (session()->connection()->version() <= QUIC_VERSION_21 ||
      !handshake_confirmed_) {
    return;
  }

  CryptoHandshakeMessage server_config_update_message;
  if (!crypto_config_.BuildServerConfigUpdateMessage(
          session()->connection()->peer_address(),
          session()->connection()->clock(),
          session()->connection()->random_generator(),
          crypto_negotiated_params_,
          cached_network_params,
          &server_config_update_message)) {
    DVLOG(1) << "Server: Failed to build server config update (SCUP)!";
    return;
  }

  DVLOG(1) << "Server: Sending server config update"
           << (on_handshake_complete ? " immediately after handshake: " : ": ")
           << server_config_update_message.DebugString();
  const QuicData& data = server_config_update_message.GetSerialized();
  WriteOrBufferData(string(data.data(), data.length()), false, nullptr);

  ++num_server_config_update_messages_sent_;
}

void QuicCryptoServerStream::OnServerHelloAcked() {
  session()->connection()->OnHandshakeComplete();
}

void QuicCryptoServerStream::set_previous_cached_network_params(
    CachedNetworkParameters cached_network_params) {
  previous_cached_network_params_.reset(
      new CachedNetworkParameters(cached_network_params));
}

bool QuicCryptoServerStream::GetBase64SHA256ClientChannelID(
    string* output) const {
  if (!encryption_established_ ||
      crypto_negotiated_params_.channel_id.empty()) {
    return false;
  }

  const string& channel_id(crypto_negotiated_params_.channel_id);
  scoped_ptr<crypto::SecureHash> hash(
      crypto::SecureHash::Create(crypto::SecureHash::SHA256));
  hash->Update(channel_id.data(), channel_id.size());
  uint8 digest[32];
  hash->Finish(digest, sizeof(digest));

  base::Base64Encode(string(
      reinterpret_cast<const char*>(digest), sizeof(digest)), output);
  // Remove padding.
  size_t len = output->size();
  if (len >= 2) {
    if ((*output)[len - 1] == '=') {
      len--;
      if ((*output)[len - 1] == '=') {
        len--;
      }
      output->resize(len);
    }
  }
  return true;
}

QuicErrorCode QuicCryptoServerStream::ProcessClientHello(
    const CryptoHandshakeMessage& message,
    const ValidateClientHelloResultCallback::Result& result,
    CryptoHandshakeMessage* reply,
    string* error_details) {
  // Store the bandwidth estimate from the client.
  if (FLAGS_quic_store_cached_network_params_from_chlo &&
      result.cached_network_params.bandwidth_estimate_bytes_per_second() > 0) {
    previous_cached_network_params_.reset(
        new CachedNetworkParameters(result.cached_network_params));
  }

  return crypto_config_.ProcessClientHello(
      result,
      session()->connection()->connection_id(),
      session()->connection()->peer_address(),
      session()->connection()->version(),
      session()->connection()->supported_versions(),
      session()->connection()->clock(),
      session()->connection()->random_generator(),
      &crypto_negotiated_params_, reply, error_details);
}

void QuicCryptoServerStream::OverrideQuicConfigDefaults(QuicConfig* config) {
}

CachedNetworkParameters*
QuicCryptoServerStream::get_previous_cached_network_params() {
  return previous_cached_network_params_.get();
}

QuicCryptoServerStream::ValidateCallback::ValidateCallback(
    QuicCryptoServerStream* parent) : parent_(parent) {
}

void QuicCryptoServerStream::ValidateCallback::Cancel() { parent_ = nullptr; }

void QuicCryptoServerStream::ValidateCallback::RunImpl(
    const CryptoHandshakeMessage& client_hello,
    const Result& result) {
  if (parent_ != nullptr) {
    parent_->FinishProcessingHandshakeMessage(client_hello, result);
  }
}

}  // namespace net