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#pragma once
#include "streams.h"
#include <cryptopp/aes.h>
#include <cryptopp/gcm.h>
#include <cryptopp/osrng.h>
#include <cryptopp/rng.h>
#include <cryptopp/secblock.h>
namespace securefs
{
namespace lite
{
class CorruptedStreamException : public ExceptionBase
{
public:
std::string message() const override;
};
class AESGCMCryptStream : public BlockBasedStream
{
private:
CryptoPP::GCM<CryptoPP::AES>::Encryption m_encryptor;
CryptoPP::GCM<CryptoPP::AES>::Decryption m_decryptor;
std::shared_ptr<StreamBase> m_stream;
std::unique_ptr<byte[]> m_buffer, m_auxiliary;
unsigned m_iv_size, m_padding_size;
bool m_check;
public:
length_type get_block_size() const noexcept { return m_block_size; }
length_type get_iv_size() const noexcept { return m_iv_size; }
static constexpr unsigned get_mac_size() noexcept { return 16; }
static constexpr length_type get_id_size() noexcept { return 16; }
length_type get_header_size() const noexcept { return get_id_size() + get_padding_size(); }
length_type get_underlying_block_size() const noexcept
{
return get_block_size() + get_iv_size() + get_mac_size();
}
unsigned get_padding_size() const noexcept { return m_padding_size; }
protected:
length_type read_block(offset_type block_number, void* output) override;
void write_block(offset_type block_number, const void* input, length_type size) override;
void adjust_logical_size(length_type length) override;
public:
explicit AESGCMCryptStream(std::shared_ptr<StreamBase> stream,
const key_type& master_key,
unsigned block_size = 4096,
unsigned iv_size = 12,
bool check = true,
unsigned max_padding_size = 0,
CryptoPP::ECB_Mode<CryptoPP::AES>::Encryption* padding_aes
= nullptr);
~AESGCMCryptStream();
virtual length_type size() const override;
virtual void flush() override;
virtual bool is_sparse() const noexcept override;
// Calculates the size of `AESGCMCryptStream` based on its underlying stream size. This only
// works when padding is not enabled.
static length_type calculate_real_size(length_type underlying_size,
length_type block_size,
length_type iv_size) noexcept;
};
} // namespace lite
} // namespace securefs
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