diff options
Diffstat (limited to 'comm/third_party/botan/src/lib/tls/tls_session_key.cpp')
-rw-r--r-- | comm/third_party/botan/src/lib/tls/tls_session_key.cpp | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/comm/third_party/botan/src/lib/tls/tls_session_key.cpp b/comm/third_party/botan/src/lib/tls/tls_session_key.cpp new file mode 100644 index 0000000000..2066810413 --- /dev/null +++ b/comm/third_party/botan/src/lib/tls/tls_session_key.cpp @@ -0,0 +1,101 @@ +/* +* TLS Session Key +* (C) 2004-2006,2011,2016,2019 Jack Lloyd +* +* Botan is released under the Simplified BSD License (see license.txt) +*/ + +#include <botan/internal/tls_session_key.h> +#include <botan/internal/tls_handshake_state.h> +#include <botan/tls_messages.h> +#include <botan/kdf.h> + +namespace Botan { + +namespace TLS { + +/** +* Session_Keys Constructor +*/ +Session_Keys::Session_Keys(const Handshake_State* state, + const secure_vector<uint8_t>& pre_master_secret, + bool resuming) + { + const size_t cipher_keylen = state->ciphersuite().cipher_keylen(); + const size_t mac_keylen = state->ciphersuite().mac_keylen(); + const size_t cipher_nonce_bytes = state->ciphersuite().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 }; + + std::unique_ptr<KDF> 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(state->version(), + state->ciphersuite().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); + + copy_mem(&m_c_aead[0], key_data, mac_keylen); + copy_mem(&m_s_aead[0], key_data + mac_keylen, mac_keylen); + + 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); + + m_c_nonce.resize(cipher_nonce_bytes); + m_s_nonce.resize(cipher_nonce_bytes); + + copy_mem(&m_c_nonce[0], key_data + 2*(mac_keylen + cipher_keylen), cipher_nonce_bytes); + copy_mem(&m_s_nonce[0], key_data + 2*(mac_keylen + cipher_keylen) + cipher_nonce_bytes, cipher_nonce_bytes); + } + +} + +} |