rocksdb/env/env_encryption_ctr.h
Mark Rambacher 42ba60b3ba Make EncryptionProvider and BlockCipher into Customizable objects (#8354)
Summary:
Made the EncryptionProvider and BlockCipher classes inherit from Customizable.  Added/fixed the CreateFromString method to these classes to create instances from builtin or registered classes.  Added tests to verify that instances can be registered and retrieved as appropriate.

Added the ability to configure the builtin (CTR, ROT13) classes from configurable properties.  Added the appropriate tests.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8354

Reviewed By: zhichao-cao

Differential Revision: D29558949

Pulled By: mrambacher

fbshipit-source-id: c20286b32d179777e060f51a58943e9b0cf81d04
2021-07-16 07:58:51 -07:00

111 lines
4.3 KiB
C++

// Copyright (c) 2016-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#pragma once
#if !defined(ROCKSDB_LITE)
#include "rocksdb/env_encryption.h"
namespace ROCKSDB_NAMESPACE {
// CTRCipherStream implements BlockAccessCipherStream using an
// Counter operations mode.
// See https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation
//
// Note: This is a possible implementation of BlockAccessCipherStream,
// it is considered suitable for use.
class CTRCipherStream final : public BlockAccessCipherStream {
private:
std::shared_ptr<BlockCipher> cipher_;
std::string iv_;
uint64_t initialCounter_;
public:
CTRCipherStream(const std::shared_ptr<BlockCipher>& c, const char* iv,
uint64_t initialCounter)
: cipher_(c), iv_(iv, c->BlockSize()), initialCounter_(initialCounter){};
virtual ~CTRCipherStream(){};
// BlockSize returns the size of each block supported by this cipher stream.
size_t BlockSize() override { return cipher_->BlockSize(); }
protected:
// Allocate scratch space which is passed to EncryptBlock/DecryptBlock.
void AllocateScratch(std::string&) override;
// Encrypt a block of data at the given block index.
// Length of data is equal to BlockSize();
Status EncryptBlock(uint64_t blockIndex, char* data, char* scratch) override;
// Decrypt a block of data at the given block index.
// Length of data is equal to BlockSize();
Status DecryptBlock(uint64_t blockIndex, char* data, char* scratch) override;
};
// This encryption provider uses a CTR cipher stream, with a given block cipher
// and IV.
//
// Note: This is a possible implementation of EncryptionProvider,
// it is considered suitable for use, provided a safe BlockCipher is used.
class CTREncryptionProvider : public EncryptionProvider {
private:
std::shared_ptr<BlockCipher> cipher_;
protected:
// For optimal performance when using direct IO, the prefix length should be a
// multiple of the page size. This size is to ensure the first real data byte
// is placed at largest known alignment point for direct io.
const static size_t defaultPrefixLength = 4096;
public:
explicit CTREncryptionProvider(
const std::shared_ptr<BlockCipher>& c = nullptr);
virtual ~CTREncryptionProvider() {}
static const char* kClassName() { return "CTR"; }
const char* Name() const override { return kClassName(); }
// GetPrefixLength returns the length of the prefix that is added to every
// file
// and used for storing encryption options.
// For optimal performance when using direct IO, the prefix length should be a
// multiple of the page size.
size_t GetPrefixLength() const override;
// CreateNewPrefix initialized an allocated block of prefix memory
// for a new file.
Status CreateNewPrefix(const std::string& fname, char* prefix,
size_t prefixLength) const override;
// CreateCipherStream creates a block access cipher stream for a file given
// given name and options.
Status CreateCipherStream(
const std::string& fname, const EnvOptions& options, Slice& prefix,
std::unique_ptr<BlockAccessCipherStream>* result) override;
Status AddCipher(const std::string& descriptor, const char* /*cipher*/,
size_t /*len*/, bool /*for_write*/) override;
protected:
// PopulateSecretPrefixPart initializes the data into a new prefix block
// that will be encrypted. This function will store the data in plain text.
// It will be encrypted later (before written to disk).
// Returns the amount of space (starting from the start of the prefix)
// that has been initialized.
virtual size_t PopulateSecretPrefixPart(char* prefix, size_t prefixLength,
size_t blockSize) const;
// CreateCipherStreamFromPrefix creates a block access cipher stream for a
// file given
// given name and options. The given prefix is already decrypted.
virtual Status CreateCipherStreamFromPrefix(
const std::string& fname, const EnvOptions& options,
uint64_t initialCounter, const Slice& iv, const Slice& prefix,
std::unique_ptr<BlockAccessCipherStream>* result);
};
} // namespace ROCKSDB_NAMESPACE
#endif // !defined(ROCKSDB_LITE)