Botan::TLS::Session_Keys Class Reference

#include <tls_session_key.h>

Public Member Functions
const secure_vector< uint8_t > &	aead_key (Connection_Side side) const
const secure_vector< uint8_t > &	client_aead_key () const
const std::vector< uint8_t > &	client_nonce () const
const secure_vector< uint8_t > &	master_secret () const
const std::vector< uint8_t > &	nonce (Connection_Side side) const
const secure_vector< uint8_t > &	server_aead_key () const
const std::vector< uint8_t > &	server_nonce () const
	Session_Keys ()=default
	Session_Keys (const Handshake_State *state, const secure_vector< uint8_t > &pre_master_secret, bool resuming)

Detailed Description

TLS Session Keys

Definition at line 21 of file tls_session_key.h.

Constructor & Destructor Documentation

Session_Keys() [1/2]

Botan::TLS::Session_Keys::Session_Keys ( )

default

Session_Keys() [2/2]

Botan::TLS::Session_Keys::Session_Keys	(	const Handshake_State *	state,
		const secure_vector< uint8_t > &	pre_master_secret,
		bool	resuming )

Parameters

state	state the handshake state
pre_master_secret	the pre-master secret
resuming	whether this TLS session is resumed

Session_Keys Constructor

Definition at line 20 of file tls_session_key.cpp.

                                          {
   BOTAN_ASSERT_NONNULL(state);
   BOTAN_ASSERT_NONNULL(state->client_hello());
   BOTAN_ASSERT_NONNULL(state->server_hello());
 
   const auto& suite = state->ciphersuite();
   BOTAN_STATE_CHECK(suite.valid());
 
   const size_t cipher_keylen = suite.cipher_keylen();
   const size_t mac_keylen = suite.mac_keylen();
   const size_t cipher_nonce_bytes = suite.nonce_bytes_from_handshake();
 
   const bool extended_master_secret = state->server_hello()->supports_extended_master_secret();
 
   const size_t prf_gen = 2 * (mac_keylen + cipher_keylen + cipher_nonce_bytes);
 
   const uint8_t MASTER_SECRET_MAGIC[] = {0x6D, 0x61, 0x73, 0x74, 0x65, 0x72, 0x20, 0x73, 0x65, 0x63, 0x72, 0x65, 0x74};
 
   const uint8_t EXT_MASTER_SECRET_MAGIC[] = {0x65, 0x78, 0x74, 0x65, 0x6E, 0x64, 0x65, 0x64, 0x20, 0x6D, 0x61,
                                              0x73, 0x74, 0x65, 0x72, 0x20, 0x73, 0x65, 0x63, 0x72, 0x65, 0x74};
 
   const uint8_t KEY_GEN_MAGIC[] = {0x6B, 0x65, 0x79, 0x20, 0x65, 0x78, 0x70, 0x61, 0x6E, 0x73, 0x69, 0x6F, 0x6E};
 
   auto prf = state->protocol_specific_prf();
 
   if(resuming) {
      // This is actually the master secret saved as part of the session
      m_master_sec = pre_master_secret;
   } else {
      std::vector<uint8_t> salt;
      std::vector<uint8_t> label;
      if(extended_master_secret) {
         label.assign(EXT_MASTER_SECRET_MAGIC, EXT_MASTER_SECRET_MAGIC + sizeof(EXT_MASTER_SECRET_MAGIC));
         salt += state->hash().final(suite.prf_algo());
      } else {
         label.assign(MASTER_SECRET_MAGIC, MASTER_SECRET_MAGIC + sizeof(MASTER_SECRET_MAGIC));
         salt += state->client_hello()->random();
         salt += state->server_hello()->random();
      }
 
      m_master_sec = prf->derive_key(48, pre_master_secret, salt, label);
   }
 
   std::vector<uint8_t> salt;
   std::vector<uint8_t> label;
   label.assign(KEY_GEN_MAGIC, KEY_GEN_MAGIC + sizeof(KEY_GEN_MAGIC));
   salt += state->server_hello()->random();
   salt += state->client_hello()->random();
 
   const secure_vector<uint8_t> prf_output = prf->derive_key(
      prf_gen, m_master_sec.data(), m_master_sec.size(), salt.data(), salt.size(), label.data(), label.size());
 
   const uint8_t* key_data = prf_output.data();
 
   m_c_aead.resize(mac_keylen + cipher_keylen);
   m_s_aead.resize(mac_keylen + cipher_keylen);
 
   // NOLINTBEGIN(readability-container-data-pointer)
   copy_mem(&m_c_aead[0], key_data, mac_keylen);
   copy_mem(&m_s_aead[0], key_data + mac_keylen, mac_keylen);
   // NOLINTEND(readability-container-data-pointer)
 
   // Key is not used for NULL suites
   if(cipher_keylen > 0) {
      copy_mem(&m_c_aead[mac_keylen], key_data + 2 * mac_keylen, cipher_keylen);
      copy_mem(&m_s_aead[mac_keylen], key_data + 2 * mac_keylen + cipher_keylen, cipher_keylen);
   } else {
      BOTAN_STATE_CHECK(suite.null_ciphersuite());
   }
 
   // Nonce is not used for NULL suites
   if(cipher_nonce_bytes > 0) {
      const uint8_t* c_nonce_bytes = key_data + 2 * (mac_keylen + cipher_keylen);
      m_c_nonce.assign(c_nonce_bytes, c_nonce_bytes + cipher_nonce_bytes);
 
      const uint8_t* s_nonce_bytes = key_data + 2 * (mac_keylen + cipher_keylen) + cipher_nonce_bytes;
      m_s_nonce.assign(s_nonce_bytes, s_nonce_bytes + cipher_nonce_bytes);
   } else {
      BOTAN_STATE_CHECK(suite.null_ciphersuite());
   }
}

References BOTAN_ASSERT_NONNULL, BOTAN_STATE_CHECK, Botan::TLS::Handshake_State::ciphersuite(), Botan::TLS::Handshake_State::client_hello(), Botan::copy_mem(), Botan::TLS::Handshake_Hash::final(), Botan::TLS::Handshake_State::hash(), Botan::TLS::Handshake_State::protocol_specific_prf(), and Botan::TLS::Handshake_State::server_hello().

Member Function Documentation

aead_key()

const secure_vector< uint8_t > & Botan::TLS::Session_Keys::aead_key ( Connection_Side side ) const

inline

Definition at line 48 of file tls_session_key.h.

                                                                         {
         return (side == Connection_Side::Client) ? client_aead_key() : server_aead_key();
      }

References Botan::TLS::Client, client_aead_key(), and server_aead_key().

Referenced by Botan::TLS::Connection_Cipher_State::Connection_Cipher_State().

client_aead_key()

const secure_vector< uint8_t > & Botan::TLS::Session_Keys::client_aead_key ( ) const

inline

Returns

client AEAD key

Definition at line 26 of file tls_session_key.h.

{ return m_c_aead; }

Referenced by aead_key().

client_nonce()

const std::vector< uint8_t > & Botan::TLS::Session_Keys::client_nonce ( ) const

inline

Returns

client nonce

Definition at line 36 of file tls_session_key.h.

{ return m_c_nonce; }

Referenced by nonce().

master_secret()

const secure_vector< uint8_t > & Botan::TLS::Session_Keys::master_secret ( ) const

inline

Returns

TLS master secret

Definition at line 46 of file tls_session_key.h.

{ return m_master_sec; }

nonce()

const std::vector< uint8_t > & Botan::TLS::Session_Keys::nonce ( Connection_Side side ) const

inline

Definition at line 52 of file tls_session_key.h.

                                                                  {
         return (side == Connection_Side::Client) ? client_nonce() : server_nonce();
      }

References Botan::TLS::Client, client_nonce(), and server_nonce().

Referenced by Botan::TLS::Connection_Cipher_State::Connection_Cipher_State().

server_aead_key()

const secure_vector< uint8_t > & Botan::TLS::Session_Keys::server_aead_key ( ) const

inline

Returns

server AEAD key

Definition at line 31 of file tls_session_key.h.

{ return m_s_aead; }

Referenced by aead_key().

server_nonce()

const std::vector< uint8_t > & Botan::TLS::Session_Keys::server_nonce ( ) const

inline

Returns

server nonce

Definition at line 41 of file tls_session_key.h.

{ return m_s_nonce; }

Referenced by nonce().

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The documentation for this class was generated from the following files:

• src/lib/tls/tls12/tls_session_key.h
• src/lib/tls/tls12/tls_session_key.cpp