OpenSSLEVPCipher.h

Go to the documentation of this file.

/*
 *  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/aead/AESGCM128.h>
#include <fizz/crypto/aead/Aead.h>
#include <fizz/crypto/aead/IOBufUtil.h>
#include <folly/Conv.h>
#include <folly/Memory.h>
#include <folly/Range.h>
#include <folly/String.h>
#include <folly/lang/Bits.h>
#include <folly/ssl/OpenSSLPtrTypes.h>
#include <glog/logging.h>
#include <openssl/evp.h>

namespace fizz {

template <typename EVPImpl>
class OpenSSLEVPCipher : public Aead {
  static_assert(EVPImpl::kIVLength >= sizeof(uint64_t), "iv too small");

 public:
  OpenSSLEVPCipher();
  ~OpenSSLEVPCipher() override = default;

  OpenSSLEVPCipher(OpenSSLEVPCipher&& other) = default;
  OpenSSLEVPCipher& operator=(OpenSSLEVPCipher&& other) = default;

  void setKey(TrafficKey trafficKey) override;

  size_t keyLength() const override {
    return EVPImpl::kKeyLength;
  }

  size_t ivLength() const override {
    return EVPImpl::kIVLength;
  }

  // If plaintext is not shared, encrypt in place and append a tag,
  // either in the tail room if available, or by appending a new buf
  // If plaintext is shared, alloc a new output and encrypt to output.
  // The returned buffer will have head room == headroom_
  std::unique_ptr<folly::IOBuf> encrypt(
      std::unique_ptr<folly::IOBuf>&& plaintext,
      const folly::IOBuf* associatedData,
      uint64_t seqNum) const override;

  folly::Optional<std::unique_ptr<folly::IOBuf>> tryDecrypt(
      std::unique_ptr<folly::IOBuf>&& ciphertext,
      const folly::IOBuf* associatedData,
      uint64_t seqNum) const override;

  size_t getCipherOverhead() const override;

  void setEncryptedBufferHeadroom(size_t headroom) override {
    headroom_ = headroom;
  }

 private:
  std::array<uint8_t, EVPImpl::kIVLength> createIV(uint64_t seqNum) const;

  TrafficKey trafficKey_;
  size_t headroom_{5};

  folly::ssl::EvpCipherCtxUniquePtr encryptCtx_;
  folly::ssl::EvpCipherCtxUniquePtr decryptCtx_;
};
} // namespace fizz
#include <fizz/crypto/aead/OpenSSLEVPCipher-inl.h>