From b3180551851d6f736a98eb059d5b46b0872666e2 Mon Sep 17 00:00:00 2001 From: Mark Haines Date: Wed, 19 Aug 2015 17:18:09 +0100 Subject: Replace hard coded references to the 32-byte key length with a constant, add utilities for copying data to and from fixed sized arrays --- src/session.cpp | 123 +++++++++++++++++++++++++++----------------------------- 1 file changed, 59 insertions(+), 64 deletions(-) (limited to 'src/session.cpp') diff --git a/src/session.cpp b/src/session.cpp index 18f0000..71c80e4 100644 --- a/src/session.cpp +++ b/src/session.cpp @@ -24,7 +24,6 @@ namespace { -static const std::size_t KEY_LENGTH = 32; static const std::uint8_t PROTOCOL_VERSION = 0x3; static const std::uint8_t ROOT_KDF_INFO[] = "OLM_ROOT"; @@ -51,7 +50,7 @@ olm::Session::Session( std::size_t olm::Session::new_outbound_session_random_length() { - return KEY_LENGTH * 2; + return olm::KEY_LENGTH * 2; } @@ -66,35 +65,35 @@ std::size_t olm::Session::new_outbound_session( return std::size_t(-1); } - Curve25519KeyPair base_key; + olm::Curve25519KeyPair base_key; olm::curve25519_generate_key(random, base_key); - Curve25519KeyPair ratchet_key; - olm::curve25519_generate_key(random + 32, ratchet_key); + olm::Curve25519KeyPair ratchet_key; + olm::curve25519_generate_key(random + olm::KEY_LENGTH, ratchet_key); + + olm::Curve25519KeyPair const & alice_identity_key_pair = ( + local_account.identity_keys.curve25519_key + ); received_message = false; - alice_identity_key = local_account.identity_keys.curve25519_key; + alice_identity_key = alice_identity_key_pair; alice_base_key = base_key; bob_one_time_key = one_time_key; - std::uint8_t shared_secret[96]; + std::uint8_t secret[3 * olm::KEY_LENGTH]; + std::uint8_t * pos = secret; - olm::curve25519_shared_secret( - local_account.identity_keys.curve25519_key, - one_time_key, shared_secret - ); - olm::curve25519_shared_secret( - base_key, identity_key, shared_secret + 32 - ); - olm::curve25519_shared_secret( - base_key, one_time_key, shared_secret + 64 - ); + olm::curve25519_shared_secret(alice_identity_key_pair, one_time_key, pos); + pos += olm::KEY_LENGTH; + olm::curve25519_shared_secret(base_key, identity_key, pos); + pos += olm::KEY_LENGTH; + olm::curve25519_shared_secret(base_key, one_time_key, pos); - ratchet.initialise_as_alice(shared_secret, 96, ratchet_key); + ratchet.initialise_as_alice(secret, sizeof(secret), ratchet_key); olm::unset(base_key); olm::unset(ratchet_key); - olm::unset(shared_secret); + olm::unset(secret); return std::size_t(0); } @@ -107,13 +106,13 @@ static bool check_message_fields( bool ok = true; ok = ok && (have_their_identity_key || reader.identity_key); if (reader.identity_key) { - ok = ok && reader.identity_key_length == KEY_LENGTH; + ok = ok && reader.identity_key_length == olm::KEY_LENGTH; } ok = ok && reader.message; ok = ok && reader.base_key; - ok = ok && reader.base_key_length == KEY_LENGTH; + ok = ok && reader.base_key_length == olm::KEY_LENGTH; ok = ok && reader.one_time_key; - ok = ok && reader.one_time_key_length == KEY_LENGTH; + ok = ok && reader.one_time_key_length == olm::KEY_LENGTH; return ok; } @@ -135,7 +134,7 @@ std::size_t olm::Session::new_inbound_session( if (reader.identity_key && their_identity_key) { bool same = 0 == std::memcmp( - their_identity_key->public_key, reader.identity_key, KEY_LENGTH + their_identity_key->public_key, reader.identity_key, olm::KEY_LENGTH ); if (!same) { last_error = olm::ErrorCode::BAD_MESSAGE_KEY_ID; @@ -150,16 +149,16 @@ std::size_t olm::Session::new_inbound_session( ); if (!message_reader.ratchet_key - || message_reader.ratchet_key_length != KEY_LENGTH) { + || message_reader.ratchet_key_length != olm::KEY_LENGTH) { last_error = olm::ErrorCode::BAD_MESSAGE_FORMAT; return std::size_t(-1); } - std::memcpy(alice_identity_key.public_key, reader.identity_key, 32); - std::memcpy(alice_base_key.public_key, reader.base_key, 32); - std::memcpy(bob_one_time_key.public_key, reader.one_time_key, 32); + olm::load_array(alice_identity_key.public_key, reader.identity_key); + olm::load_array(alice_base_key.public_key, reader.base_key); + olm::load_array(bob_one_time_key.public_key, reader.one_time_key); olm::Curve25519PublicKey ratchet_key; - std::memcpy(ratchet_key.public_key, message_reader.ratchet_key, 32); + olm::load_array(ratchet_key.public_key, message_reader.ratchet_key); olm::OneTimeKey const * our_one_time_key = local_account.lookup_key( bob_one_time_key @@ -170,27 +169,28 @@ std::size_t olm::Session::new_inbound_session( return std::size_t(-1); } - std::uint8_t shared_secret[96]; - - olm::curve25519_shared_secret( - our_one_time_key->key, alice_identity_key, shared_secret - ); - olm::curve25519_shared_secret( - local_account.identity_keys.curve25519_key, - alice_base_key, shared_secret + 32 - ); - olm::curve25519_shared_secret( - our_one_time_key->key, alice_base_key, shared_secret + 64 + olm::Curve25519KeyPair const & bob_identity_key = ( + local_account.identity_keys.curve25519_key ); + olm::Curve25519KeyPair const & bob_one_time_key = our_one_time_key->key; + + std::uint8_t secret[olm::KEY_LENGTH * 3]; + std::uint8_t * pos = secret; + olm::curve25519_shared_secret(bob_one_time_key, alice_identity_key, pos); + pos += olm::KEY_LENGTH; + olm::curve25519_shared_secret(bob_identity_key, alice_base_key, pos); + pos += olm::KEY_LENGTH; + olm::curve25519_shared_secret(bob_one_time_key, alice_base_key, pos); - ratchet.initialise_as_bob(shared_secret, 96, ratchet_key); + ratchet.initialise_as_bob(secret, sizeof(secret), ratchet_key); + olm::unset(secret); return std::size_t(0); } std::size_t olm::Session::session_id_length() { - return 32; + return olm::SHA256_OUTPUT_LENGTH; } @@ -201,10 +201,11 @@ std::size_t olm::Session::session_id( last_error = olm::ErrorCode::OUTPUT_BUFFER_TOO_SMALL; return std::size_t(-1); } - std::uint8_t tmp[96]; - std::memcpy(tmp, alice_identity_key.public_key, 32); - std::memcpy(tmp + 32, alice_base_key.public_key, 32); - std::memcpy(tmp + 64, bob_one_time_key.public_key, 32); + std::uint8_t tmp[olm::KEY_LENGTH * 3]; + std::uint8_t * pos = tmp; + pos = olm::store_array(pos, alice_identity_key.public_key); + pos = olm::store_array(pos, alice_base_key.public_key); + pos = olm::store_array(pos, bob_one_time_key.public_key); olm::sha256(tmp, sizeof(tmp), id); return session_id_length(); } @@ -224,20 +225,20 @@ bool olm::Session::matches_inbound_session( bool same = true; if (reader.identity_key) { same = same && 0 == std::memcmp( - reader.identity_key, alice_identity_key.public_key, KEY_LENGTH + reader.identity_key, alice_identity_key.public_key, olm::KEY_LENGTH ); } if (their_identity_key) { same = same && 0 == std::memcmp( their_identity_key->public_key, alice_identity_key.public_key, - KEY_LENGTH + olm::KEY_LENGTH ); } same = same && 0 == std::memcmp( - reader.base_key, alice_base_key.public_key, KEY_LENGTH + reader.base_key, alice_base_key.public_key, olm::KEY_LENGTH ); same = same && 0 == std::memcmp( - reader.one_time_key, bob_one_time_key.public_key, KEY_LENGTH + reader.one_time_key, bob_one_time_key.public_key, olm::KEY_LENGTH ); return same; } @@ -264,9 +265,9 @@ std::size_t olm::Session::encrypt_message_length( } return encode_one_time_key_message_length( - KEY_LENGTH, - KEY_LENGTH, - KEY_LENGTH, + olm::KEY_LENGTH, + olm::KEY_LENGTH, + olm::KEY_LENGTH, message_length ); } @@ -298,21 +299,15 @@ std::size_t olm::Session::encrypt( encode_one_time_key_message( writer, PROTOCOL_VERSION, - KEY_LENGTH, - KEY_LENGTH, - KEY_LENGTH, + olm::KEY_LENGTH, + olm::KEY_LENGTH, + olm::KEY_LENGTH, message_body_length, message ); - std::memcpy( - writer.one_time_key, bob_one_time_key.public_key, KEY_LENGTH - ); - std::memcpy( - writer.identity_key, alice_identity_key.public_key, KEY_LENGTH - ); - std::memcpy( - writer.base_key, alice_base_key.public_key, KEY_LENGTH - ); + olm::store_array(writer.one_time_key, bob_one_time_key.public_key); + olm::store_array(writer.identity_key, alice_identity_key.public_key); + olm::store_array(writer.base_key, alice_base_key.public_key); message_body = writer.message; } -- cgit v1.2.3