KeyScheduler.h

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/*
 *  Copyright (c) 2018-present, Facebook, Inc.
 *  All rights reserved.
 *
 *  This source code is licensed under the BSD-style license found in the
 *  LICENSE file in the root directory of this source tree.
 */

#pragma once

#include <fizz/crypto/KeyDerivation.h>
#include <fizz/crypto/aead/Aead.h>
#include <folly/Optional.h>

namespace fizz {

enum class EarlySecrets {
  ExternalPskBinder,
  ResumptionPskBinder,
  ClientEarlyTraffic,
  EarlyExporter
};

enum class HandshakeSecrets { ClientHandshakeTraffic, ServerHandshakeTraffic };

enum class MasterSecrets { ExporterMaster, ResumptionMaster };

enum class AppTrafficSecrets { ClientAppTraffic, ServerAppTraffic };

class KeyScheduler {
 public:
  explicit KeyScheduler(std::unique_ptr<KeyDerivation> deriver)
      : deriver_(std::move(deriver)) {}
  virtual ~KeyScheduler() = default;

  virtual void deriveEarlySecret(folly::ByteRange psk);

  virtual void deriveHandshakeSecret();

  virtual void deriveHandshakeSecret(folly::ByteRange ecdhe);

  virtual void deriveMasterSecret();

  virtual void deriveAppTrafficSecrets(folly::ByteRange transcript);

  virtual void clearMasterSecret();

  virtual uint32_t clientKeyUpdate();

  virtual uint32_t serverKeyUpdate();

  virtual std::vector<uint8_t> getSecret(
      EarlySecrets s,
      folly::ByteRange transcript) const;
  virtual std::vector<uint8_t> getSecret(
      HandshakeSecrets s,
      folly::ByteRange transcript) const;
  virtual std::vector<uint8_t> getSecret(
      MasterSecrets s,
      folly::ByteRange transcript) const;
  virtual std::vector<uint8_t> getSecret(AppTrafficSecrets s) const;

  virtual TrafficKey getTrafficKey(
      folly::ByteRange trafficSecret,
      size_t keyLength,
      size_t ivLength) const;

  virtual Buf getResumptionSecret(
      folly::ByteRange resumptionMasterSecret,
      folly::ByteRange ticketNonce) const;

 private:
  struct EarlySecret {
    std::vector<uint8_t> secret;
  };
  struct HandshakeSecret {
    std::vector<uint8_t> secret;
  };
  struct MasterSecret {
    std::vector<uint8_t> secret;
  };
  struct AppTrafficSecret {
    std::vector<uint8_t> client;
    uint32_t clientGeneration{0};
    std::vector<uint8_t> server;
    uint32_t serverGeneration{0};
  };

  folly::Optional<boost::variant<EarlySecret, HandshakeSecret, MasterSecret>>
      secret_;
  folly::Optional<AppTrafficSecret> appTrafficSecret_;

  std::unique_ptr<KeyDerivation> deriver_;
};
} // namespace fizz