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