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/*
* TLS CBC+HMAC AEAD
* (C) 2016 Jack Lloyd
* (C) 2016 Daniel Neus, Rohde & Schwarz Cybersecurity
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#ifndef BOTAN_TLS_CBC_HMAC_AEAD_H_
#define BOTAN_TLS_CBC_HMAC_AEAD_H_
#include <botan/aead.h>
#include <botan/block_cipher.h>
#include <botan/mac.h>
#include <botan/tls_version.h>
namespace Botan::TLS {
/**
* TLS CBC+HMAC AEAD base class (GenericBlockCipher in TLS spec)
* This is the weird TLS-specific mode, not for general consumption.
*/
class BOTAN_TEST_API TLS_CBC_HMAC_AEAD_Mode : public AEAD_Mode {
public:
std::string name() const final;
void set_associated_data_n(size_t idx, std::span<const uint8_t> ad) override;
size_t update_granularity() const final;
size_t ideal_granularity() const final;
Key_Length_Specification key_spec() const final;
bool valid_nonce_length(size_t nl) const final;
size_t tag_size() const final { return m_tag_size; }
size_t default_nonce_length() const final { return m_iv_size; }
void clear() final;
void reset() final;
bool has_keying_material() const final;
protected:
TLS_CBC_HMAC_AEAD_Mode(Cipher_Dir direction,
std::unique_ptr<BlockCipher> cipher,
std::unique_ptr<MessageAuthenticationCode> mac,
size_t cipher_keylen,
size_t mac_keylen,
Protocol_Version version,
bool use_encrypt_then_mac);
size_t cipher_keylen() const { return m_cipher_keylen; }
size_t mac_keylen() const { return m_mac_keylen; }
size_t iv_size() const { return m_iv_size; }
size_t block_size() const { return m_block_size; }
bool use_encrypt_then_mac() const { return m_use_encrypt_then_mac; }
bool is_datagram_protocol() const { return m_is_datagram; }
Cipher_Mode& cbc() const { return *m_cbc; }
MessageAuthenticationCode& mac() const { return *m_mac; }
secure_vector<uint8_t>& cbc_state() { return m_cbc_state; }
std::vector<uint8_t>& assoc_data() { return m_ad; }
secure_vector<uint8_t>& msg() { return m_msg; }
std::vector<uint8_t> assoc_data_with_len(uint16_t len);
private:
void start_msg(const uint8_t nonce[], size_t nonce_len) final;
size_t process_msg(uint8_t buf[], size_t sz) final;
void key_schedule(std::span<const uint8_t> key) final;
const std::string m_cipher_name;
const std::string m_mac_name;
size_t m_cipher_keylen;
size_t m_mac_keylen;
size_t m_iv_size;
size_t m_tag_size;
size_t m_block_size;
bool m_use_encrypt_then_mac;
bool m_is_datagram;
std::unique_ptr<Cipher_Mode> m_cbc;
std::unique_ptr<MessageAuthenticationCode> m_mac;
secure_vector<uint8_t> m_cbc_state;
std::vector<uint8_t> m_ad;
secure_vector<uint8_t> m_msg;
};
/**
* TLS_CBC_HMAC_AEAD Encryption
*/
class BOTAN_TEST_API TLS_CBC_HMAC_AEAD_Encryption final : public TLS_CBC_HMAC_AEAD_Mode {
public:
/**
*/
TLS_CBC_HMAC_AEAD_Encryption(std::unique_ptr<BlockCipher> cipher,
std::unique_ptr<MessageAuthenticationCode> mac,
const size_t cipher_keylen,
const size_t mac_keylen,
const Protocol_Version version,
bool use_encrypt_then_mac) :
TLS_CBC_HMAC_AEAD_Mode(Cipher_Dir::Encryption,
std::move(cipher),
std::move(mac),
cipher_keylen,
mac_keylen,
version,
use_encrypt_then_mac) {}
void set_associated_data_n(size_t idx, std::span<const uint8_t> ad) override;
size_t output_length(size_t input_length) const override;
size_t minimum_final_size() const override { return 0; }
private:
void finish_msg(secure_vector<uint8_t>& final_block, size_t offset = 0) override;
void cbc_encrypt_record(secure_vector<uint8_t>& buffer, size_t offset, size_t padding_length);
};
/**
* TLS_CBC_HMAC_AEAD Decryption
*/
class BOTAN_TEST_API TLS_CBC_HMAC_AEAD_Decryption final : public TLS_CBC_HMAC_AEAD_Mode {
public:
/**
*/
TLS_CBC_HMAC_AEAD_Decryption(std::unique_ptr<BlockCipher> cipher,
std::unique_ptr<MessageAuthenticationCode> mac,
const size_t cipher_keylen,
const size_t mac_keylen,
const Protocol_Version version,
bool use_encrypt_then_mac) :
TLS_CBC_HMAC_AEAD_Mode(Cipher_Dir::Decryption,
std::move(cipher),
std::move(mac),
cipher_keylen,
mac_keylen,
version,
use_encrypt_then_mac) {}
size_t output_length(size_t input_length) const override;
size_t minimum_final_size() const override { return tag_size(); }
private:
void finish_msg(secure_vector<uint8_t>& final_block, size_t offset = 0) override;
void cbc_decrypt_record(uint8_t record_contents[], size_t record_len);
void perform_additional_compressions(size_t plen, size_t padlen);
};
/**
* Check the TLS padding of a record
* @param record the record bits
* @param record_len length of record
* @return 0 if padding is invalid, otherwise padding_bytes + 1
*/
BOTAN_TEST_API uint16_t check_tls_cbc_padding(const uint8_t record[], size_t record_len);
} // namespace Botan::TLS
#endif