diff options
| -rw-r--r-- | src/tls/sessions_sqlite/tls_sqlite_sess_mgr.cpp | 2 | ||||
| -rw-r--r-- | src/tls/tls_session.cpp | 90 |
2 files changed, 54 insertions, 38 deletions
diff --git a/src/tls/sessions_sqlite/tls_sqlite_sess_mgr.cpp b/src/tls/sessions_sqlite/tls_sqlite_sess_mgr.cpp index 04201efe3..4d78a5365 100644 --- a/src/tls/sessions_sqlite/tls_sqlite_sess_mgr.cpp +++ b/src/tls/sessions_sqlite/tls_sqlite_sess_mgr.cpp @@ -211,7 +211,7 @@ Session_Manager_SQLite::Session_Manager_SQLite(const std::string& passphrase, // new database case MemoryVector<byte> salt = rng.random_vec(16); - const size_t iterations = 32000; + const size_t iterations = 64 * 1024; size_t check_val = 0; m_session_key = derive_key(passphrase, &salt[0], salt.size(), diff --git a/src/tls/tls_session.cpp b/src/tls/tls_session.cpp index c01590000..2a532196d 100644 --- a/src/tls/tls_session.cpp +++ b/src/tls/tls_session.cpp @@ -133,7 +133,16 @@ std::string Session::PEM_encode() const namespace { -const u64bit ENCRYPTED_SESSION_MAGIC = 0xACE4480800000000; +const u32bit SESSION_CRYPTO_MAGIC = 0x571B0E4E; +const std::string SESSION_CRYPTO_CIPHER = "AES-256/CBC"; +const std::string SESSION_CRYPTO_MAC = "HMAC(SHA-256)"; +const std::string SESSION_CRYPTO_KDF = "KDF2(SHA-256)"; + +const size_t MAGIC_LENGTH = 4; +const size_t MAC_KEY_LENGTH = 32; +const size_t CIPHER_KEY_LENGTH = 32; +const size_t CIPHER_IV_LENGTH = 16; +const size_t MAC_OUTPUT_LENGTH = 32; } @@ -141,26 +150,30 @@ MemoryVector<byte> Session::encrypt(const SymmetricKey& master_key, RandomNumberGenerator& rng) const { - std::auto_ptr<KDF> kdf(get_kdf("KDF2(SHA-256)")); + std::auto_ptr<KDF> kdf(get_kdf(SESSION_CRYPTO_KDF)); - SymmetricKey aes_key = kdf->derive_key(32, master_key.bits_of(), - "tls.session.cipher-key"); + SymmetricKey cipher_key = + kdf->derive_key(CIPHER_KEY_LENGTH, + master_key.bits_of(), + "tls.session.cipher-key"); - SymmetricKey hmac_key = kdf->derive_key(32, master_key.bits_of(), - "tls.session.mac-key"); + SymmetricKey mac_key = + kdf->derive_key(MAC_KEY_LENGTH, + master_key.bits_of(), + "tls.session.mac-key"); - InitializationVector aes_iv(rng, 16); + InitializationVector cipher_iv(rng, 16); - std::auto_ptr<MessageAuthenticationCode> mac(get_mac("HMAC(SHA-256)")); - mac->set_key(hmac_key); + std::auto_ptr<MessageAuthenticationCode> mac(get_mac(SESSION_CRYPTO_MAC)); + mac->set_key(mac_key); - Pipe pipe(get_cipher("AES-256/CBC", aes_key, aes_iv, ENCRYPTION)); + Pipe pipe(get_cipher(SESSION_CRYPTO_CIPHER, cipher_key, cipher_iv, ENCRYPTION)); pipe.process_msg(this->DER_encode()); MemoryVector<byte> ctext = pipe.read_all(0); - MemoryVector<byte> out(8); - store_be(ENCRYPTED_SESSION_MAGIC, &out[0]); - out += aes_iv.bits_of(); + MemoryVector<byte> out(MAGIC_LENGTH); + store_be(SESSION_CRYPTO_MAGIC, &out[0]); + out += cipher_iv.bits_of(); out += ctext; mac->update(out); @@ -174,42 +187,45 @@ Session Session::decrypt(const byte buf[], size_t buf_len, { try { - /* - 8 bytes header - 16 bytes IV - 32 bytes MAC - 16 bytes per AES block * 4 blocks (absolute min amount due to - 48 bytes master secret) - */ - if(buf_len < (8 + 16 + 32 + 4*16)) + const size_t MIN_CTEXT_SIZE = 4 * 16; // due to 48 byte master secret + + if(buf_len < (MAGIC_LENGTH + + CIPHER_IV_LENGTH + + MIN_CTEXT_SIZE + + MAC_OUTPUT_LENGTH)) throw Decoding_Error("Encrypted TLS session too short to be valid"); - std::auto_ptr<KDF> kdf(get_kdf("KDF2(SHA-256)")); + if(load_be<u32bit>(buf, 0) != SESSION_CRYPTO_MAGIC) + throw Decoding_Error("Unknown header value in encrypted session"); + + std::auto_ptr<KDF> kdf(get_kdf(SESSION_CRYPTO_KDF)); - SymmetricKey hmac_key = kdf->derive_key(32, master_key.bits_of(), - "tls.session.mac-key"); + SymmetricKey mac_key = + kdf->derive_key(MAC_KEY_LENGTH, + master_key.bits_of(), + "tls.session.mac-key"); - std::auto_ptr<MessageAuthenticationCode> mac(get_mac("HMAC(SHA-256)")); - mac->set_key(hmac_key); + std::auto_ptr<MessageAuthenticationCode> mac(get_mac(SESSION_CRYPTO_MAC)); + mac->set_key(mac_key); - mac->update(&buf[0], buf_len - 32); + mac->update(&buf[0], buf_len - MAC_OUTPUT_LENGTH); MemoryVector<byte> computed_mac = mac->final(); - if(!same_mem(&buf[buf_len - 32], &computed_mac[0], computed_mac.size())) + if(!same_mem(&buf[buf_len - MAC_OUTPUT_LENGTH], &computed_mac[0], computed_mac.size())) throw Decoding_Error("MAC verification failed for encrypted session"); - const u64bit header = load_be<u64bit>(buf, 0); - - if(header != ENCRYPTED_SESSION_MAGIC) - throw Decoding_Error("Unknown header value in encrypted session"); + SymmetricKey cipher_key = + kdf->derive_key(CIPHER_KEY_LENGTH, + master_key.bits_of(), + "tls.session.cipher-key"); - SymmetricKey aes_key = kdf->derive_key(32, master_key.bits_of(), - "tls.session.cipher-key"); + InitializationVector cipher_iv(&buf[MAGIC_LENGTH], CIPHER_IV_LENGTH); - InitializationVector aes_iv(&buf[8], 16); + const size_t CTEXT_OFFSET = MAGIC_LENGTH + CIPHER_IV_LENGTH; - Pipe pipe(get_cipher("AES-256/CBC", aes_key, aes_iv, DECRYPTION)); - pipe.process_msg(&buf[8+16], buf_len - (32 + 8 + 16)); + Pipe pipe(get_cipher(SESSION_CRYPTO_CIPHER, cipher_key, cipher_iv, DECRYPTION)); + pipe.process_msg(&buf[CTEXT_OFFSET], + buf_len - (MAC_OUTPUT_LENGTH + CTEXT_OFFSET)); SecureVector<byte> ber = pipe.read_all(); return Session(&ber[0], ber.size()); |