async def _receive_handshake(self, reader: asyncio.StreamReader,
writer: asyncio.StreamWriter) -> None:
msg = await self.wait(reader.read(ENCRYPTED_AUTH_MSG_LEN),
timeout=REPLY_TIMEOUT)
ip, socket, *_ = writer.get_extra_info("peername")
remote_address = Address(ip, socket)
self.logger.debug("Receiving handshake from %s", remote_address)
got_eip8 = False
try:
ephem_pubkey, initiator_nonce, initiator_pubkey = decode_authentication(
msg, self.privkey)
except DecryptionError:
# Try to decode as EIP8
got_eip8 = True
msg_size = big_endian_to_int(msg[:2])
remaining_bytes = msg_size - ENCRYPTED_AUTH_MSG_LEN + 2
msg += await self.wait(reader.read(remaining_bytes),
timeout=REPLY_TIMEOUT)
try:
ephem_pubkey, initiator_nonce, initiator_pubkey = decode_authentication(
msg, self.privkey)
except DecryptionError as e:
self.logger.debug("Failed to decrypt handshake: %s", e)
return
initiator_remote = Node(initiator_pubkey, remote_address)
responder = HandshakeResponder(initiator_remote, self.privkey,
got_eip8, self.cancel_token)
responder_nonce = numpy.random.bytes(HASH_LEN)
auth_ack_msg = responder.create_auth_ack_message(responder_nonce)
auth_ack_ciphertext = responder.encrypt_auth_ack_message(auth_ack_msg)
# Use the `writer` to send the reply to the remote
writer.write(auth_ack_ciphertext)
await self.wait(writer.drain())
# Call `HandshakeResponder.derive_shared_secrets()` and use return values to create `Peer`
aes_secret, mac_secret, egress_mac, ingress_mac = responder.derive_secrets(
initiator_nonce=initiator_nonce,
responder_nonce=responder_nonce,
remote_ephemeral_pubkey=ephem_pubkey,
auth_init_ciphertext=msg,
auth_ack_ciphertext=auth_ack_ciphertext,
)
connection = PeerConnection(
reader=reader,
writer=writer,
aes_secret=aes_secret,
mac_secret=mac_secret,
egress_mac=egress_mac,
ingress_mac=ingress_mac,
)
# Create and register peer in peer_pool
peer = self.peer_pool.get_peer_factory().create_peer(
remote=initiator_remote, connection=connection, inbound=True)
if self.peer_pool.is_full:
await peer.disconnect(DisconnectReason.too_many_peers)
return
elif not self.peer_pool.is_valid_connection_candidate(peer.remote):
await peer.disconnect(DisconnectReason.useless_peer)
return
total_peers = len(self.peer_pool)
inbound_peer_count = len([
peer for peer in self.peer_pool.connected_nodes.values()
if peer.inbound
])
if total_peers > 1 and inbound_peer_count / total_peers > DIAL_IN_OUT_RATIO:
# make sure to have at least 1/4 outbound connections
await peer.disconnect(DisconnectReason.too_many_peers)
else:
# We use self.wait() here as a workaround for
# https://github.com/ethereum/py-evm/issues/670.
await self.wait(self.do_handshake(peer))
async def test_handshake():
# TODO: this test should be re-written to not depend on functionality in the `ETHPeer` class.
cancel_token = CancelToken("test_handshake")
use_eip8 = False
initiator_remote = kademlia.Node(
keys.PrivateKey(test_values["receiver_private_key"]).public_key,
kademlia.Address("0.0.0.0", 0, 0),
)
initiator = HandshakeInitiator(
initiator_remote,
keys.PrivateKey(test_values["initiator_private_key"]),
use_eip8,
cancel_token,
)
initiator.ephemeral_privkey = keys.PrivateKey(
test_values["initiator_ephemeral_private_key"])
responder_remote = kademlia.Node(
keys.PrivateKey(test_values["initiator_private_key"]).public_key,
kademlia.Address("0.0.0.0", 0, 0),
)
responder = HandshakeResponder(
responder_remote,
keys.PrivateKey(test_values["receiver_private_key"]),
use_eip8,
cancel_token,
)
responder.ephemeral_privkey = keys.PrivateKey(
test_values["receiver_ephemeral_private_key"])
# Check that the auth message generated by the initiator is what we expect. Notice that we
# can't use the auth_init generated here because the non-deterministic prefix would cause the
# derived secrets to not match the expected values.
_auth_init = initiator.create_auth_message(test_values["initiator_nonce"])
assert len(_auth_init) == len(test_values["auth_plaintext"])
assert (_auth_init[65:] == test_values["auth_plaintext"][65:]
) # starts with non deterministic k
# Check that encrypting and decrypting the auth_init gets us the orig msg.
_auth_init_ciphertext = initiator.encrypt_auth_message(_auth_init)
assert _auth_init == ecies.decrypt(_auth_init_ciphertext,
responder.privkey)
# Check that the responder correctly decodes the auth msg.
auth_msg_ciphertext = test_values["auth_ciphertext"]
initiator_ephemeral_pubkey, initiator_nonce, _ = decode_authentication(
auth_msg_ciphertext, responder.privkey)
assert initiator_nonce == test_values["initiator_nonce"]
assert initiator_ephemeral_pubkey == (keys.PrivateKey(
test_values["initiator_ephemeral_private_key"]).public_key)
# Check that the auth_ack msg generated by the responder is what we expect.
auth_ack_msg = responder.create_auth_ack_message(
test_values["receiver_nonce"])
assert auth_ack_msg == test_values["authresp_plaintext"]
# Check that the secrets derived from ephemeral key agreements match the expected values.
auth_ack_ciphertext = test_values["authresp_ciphertext"]
aes_secret, mac_secret, egress_mac, ingress_mac = responder.derive_secrets(
initiator_nonce,
test_values["receiver_nonce"],
initiator_ephemeral_pubkey,
auth_msg_ciphertext,
auth_ack_ciphertext,
)
assert aes_secret == test_values["aes_secret"]
assert mac_secret == test_values["mac_secret"]
# Test values are from initiator perspective, so they're reversed here.
assert ingress_mac.digest() == test_values["initial_egress_MAC"]
assert egress_mac.digest() == test_values["initial_ingress_MAC"]
# Check that the initiator secrets match as well.
responder_ephemeral_pubkey, responder_nonce = initiator.decode_auth_ack_message(
test_values["authresp_ciphertext"])
(
initiator_aes_secret,
initiator_mac_secret,
initiator_egress_mac,
initiator_ingress_mac,
) = initiator.derive_secrets(
initiator_nonce,
responder_nonce,
responder_ephemeral_pubkey,
auth_msg_ciphertext,
auth_ack_ciphertext,
)
assert initiator_aes_secret == aes_secret
assert initiator_mac_secret == mac_secret
assert initiator_ingress_mac.digest() == test_values["initial_ingress_MAC"]
assert initiator_egress_mac.digest() == test_values["initial_egress_MAC"]
# Finally, check that two Peers configured with the secrets generated above understand each
# other.
(
(responder_reader, responder_writer),
(initiator_reader, initiator_writer),
) = get_directly_connected_streams()
initiator_connection = PeerConnection(
reader=initiator_reader,
writer=initiator_writer,
aes_secret=initiator_aes_secret,
mac_secret=initiator_mac_secret,
egress_mac=initiator_egress_mac,
ingress_mac=initiator_ingress_mac,
)
initiator_peer = ParagonPeer(
remote=initiator.remote,
privkey=initiator.privkey,
connection=initiator_connection,
context=ParagonContext(),
)
initiator_peer.base_protocol.send_handshake()
responder_connection = PeerConnection(
reader=responder_reader,
writer=responder_writer,
aes_secret=aes_secret,
mac_secret=mac_secret,
egress_mac=egress_mac,
ingress_mac=ingress_mac,
)
responder_peer = ParagonPeer(
remote=responder.remote,
privkey=responder.privkey,
connection=responder_connection,
context=ParagonContext(),
)
responder_peer.base_protocol.send_handshake()
# The handshake msgs sent by each peer (above) are going to be fed directly into their remote's
# reader, and thus the read_msg() calls will return immediately.
responder_hello, _ = await responder_peer.read_msg()
initiator_hello, _ = await initiator_peer.read_msg()
assert isinstance(responder_hello, Hello)
assert isinstance(initiator_hello, Hello)
async def get_directly_linked_peers_without_handshake(
alice_factory: BasePeerFactory = None, bob_factory: BasePeerFactory = None
) -> Tuple[BasePeer, BasePeer]:
"""
See get_directly_linked_peers().
Neither the P2P handshake nor the sub-protocol handshake will be performed here.
"""
cancel_token = CancelToken("get_directly_linked_peers_without_handshake")
if alice_factory is None:
alice_factory = ParagonPeerFactory(
privkey=ecies.generate_privkey(),
context=ParagonContext(),
token=cancel_token,
listen_port=30303,
)
if bob_factory is None:
bob_factory = ParagonPeerFactory(
privkey=ecies.generate_privkey(),
context=ParagonContext(),
token=cancel_token,
listen_port=30303,
)
alice_private_key = alice_factory.privkey
bob_private_key = bob_factory.privkey
alice_remote = kademlia.Node(
bob_private_key.public_key, kademlia.Address("0.0.0.0", 0, 0)
)
bob_remote = kademlia.Node(
alice_private_key.public_key, kademlia.Address("0.0.0.0", 0, 0)
)
use_eip8 = False
initiator = auth.HandshakeInitiator(
alice_remote, alice_private_key, use_eip8, cancel_token
)
f_alice = asyncio.Future() # : 'asyncio.Future[BasePeer]'
handshake_finished = asyncio.Event()
(
(alice_reader, alice_writer),
(bob_reader, bob_writer),
) = get_directly_connected_streams()
async def do_handshake() -> None:
aes_secret, mac_secret, egress_mac, ingress_mac = await auth._handshake(
initiator, alice_reader, alice_writer, cancel_token
)
connection = PeerConnection(
reader=alice_reader,
writer=alice_writer,
aes_secret=aes_secret,
mac_secret=mac_secret,
egress_mac=egress_mac,
ingress_mac=ingress_mac,
)
alice = alice_factory.create_peer(alice_remote, connection)
f_alice.set_result(alice)
handshake_finished.set()
asyncio.ensure_future(do_handshake())
use_eip8 = False
responder = auth.HandshakeResponder(
bob_remote, bob_private_key, use_eip8, cancel_token
)
auth_cipher = await bob_reader.read(constants.ENCRYPTED_AUTH_MSG_LEN)
initiator_ephemeral_pubkey, initiator_nonce, _ = decode_authentication(
auth_cipher, bob_private_key
)
responder_nonce = keccak(os.urandom(constants.HASH_LEN))
auth_ack_msg = responder.create_auth_ack_message(responder_nonce)
auth_ack_ciphertext = responder.encrypt_auth_ack_message(auth_ack_msg)
bob_writer.write(auth_ack_ciphertext)
await handshake_finished.wait()
alice = await f_alice
aes_secret, mac_secret, egress_mac, ingress_mac = responder.derive_secrets(
initiator_nonce,
responder_nonce,
initiator_ephemeral_pubkey,
auth_cipher,
auth_ack_ciphertext,
)
assert egress_mac.digest() == alice.ingress_mac.digest()
assert ingress_mac.digest() == alice.egress_mac.digest()
connection = PeerConnection(
reader=bob_reader,
writer=bob_writer,
aes_secret=aes_secret,
mac_secret=mac_secret,
egress_mac=egress_mac,
ingress_mac=ingress_mac,
)
bob = bob_factory.create_peer(bob_remote, connection)
return alice, bob
async def test_handshake_eip8():
cancel_token = CancelToken("test_handshake_eip8")
use_eip8 = True
initiator_remote = kademlia.Node(
keys.PrivateKey(eip8_values["receiver_private_key"]).public_key,
kademlia.Address("0.0.0.0", 0, 0),
)
initiator = HandshakeInitiator(
initiator_remote,
keys.PrivateKey(eip8_values["initiator_private_key"]),
use_eip8,
cancel_token,
)
initiator.ephemeral_privkey = keys.PrivateKey(
eip8_values["initiator_ephemeral_private_key"])
responder_remote = kademlia.Node(
keys.PrivateKey(eip8_values["initiator_private_key"]).public_key,
kademlia.Address("0.0.0.0", 0, 0),
)
responder = HandshakeResponder(
responder_remote,
keys.PrivateKey(eip8_values["receiver_private_key"]),
use_eip8,
cancel_token,
)
responder.ephemeral_privkey = keys.PrivateKey(
eip8_values["receiver_ephemeral_private_key"])
auth_init_ciphertext = eip8_values["auth_init_ciphertext"]
# Check that we can decrypt/decode the EIP-8 auth init message.
initiator_ephemeral_pubkey, initiator_nonce, _ = decode_authentication(
auth_init_ciphertext, responder.privkey)
assert initiator_nonce == eip8_values["initiator_nonce"]
assert initiator_ephemeral_pubkey == (keys.PrivateKey(
eip8_values["initiator_ephemeral_private_key"]).public_key)
responder_nonce = eip8_values["receiver_nonce"]
auth_ack_ciphertext = eip8_values["auth_ack_ciphertext"]
aes_secret, mac_secret, egress_mac, ingress_mac = responder.derive_secrets(
initiator_nonce,
responder_nonce,
initiator_ephemeral_pubkey,
auth_init_ciphertext,
auth_ack_ciphertext,
)
# Check that the secrets derived by the responder match the expected values.
assert aes_secret == eip8_values["expected_aes_secret"]
assert mac_secret == eip8_values["expected_mac_secret"]
# Also according to https://github.com/ethereum/EIPs/blob/master/EIPS/eip-8.md, running B's
# ingress-mac keccak state on the string "foo" yields the following hash:
ingress_mac_copy = ingress_mac.copy()
ingress_mac_copy.update(b"foo")
assert ingress_mac_copy.digest().hex() == (
"0c7ec6340062cc46f5e9f1e3cf86f8c8c403c5a0964f5df0ebd34a75ddc86db5")
responder_ephemeral_pubkey, responder_nonce = initiator.decode_auth_ack_message(
auth_ack_ciphertext)
(
initiator_aes_secret,
initiator_mac_secret,
initiator_egress_mac,
initiator_ingress_mac,
) = initiator.derive_secrets(
initiator_nonce,
responder_nonce,
responder_ephemeral_pubkey,
auth_init_ciphertext,
auth_ack_ciphertext,
)
# Check that the secrets derived by the initiator match the expected values.
assert initiator_aes_secret == eip8_values["expected_aes_secret"]
assert initiator_mac_secret == eip8_values["expected_mac_secret"]
# Finally, check that two Peers configured with the secrets generated above understand each
# other.
(
(responder_reader, responder_writer),
(initiator_reader, initiator_writer),
) = get_directly_connected_streams()
initiator_connection = PeerConnection(
reader=initiator_reader,
writer=initiator_writer,
aes_secret=initiator_aes_secret,
mac_secret=initiator_mac_secret,
egress_mac=initiator_egress_mac,
ingress_mac=initiator_ingress_mac,
)
initiator_peer = ParagonPeer(
remote=initiator.remote,
privkey=initiator.privkey,
connection=initiator_connection,
context=ParagonContext(),
)
initiator_peer.base_protocol.send_handshake()
responder_connection = PeerConnection(
reader=responder_reader,
writer=responder_writer,
aes_secret=aes_secret,
mac_secret=mac_secret,
egress_mac=egress_mac,
ingress_mac=ingress_mac,
)
responder_peer = ParagonPeer(
remote=responder.remote,
privkey=responder.privkey,
connection=responder_connection,
context=ParagonContext(),
)
responder_peer.base_protocol.send_handshake()
# The handshake msgs sent by each peer (above) are going to be fed directly into their remote's
# reader, and thus the read_msg() calls will return immediately.
responder_hello, _ = await responder_peer.read_msg()
initiator_hello, _ = await initiator_peer.read_msg()
assert isinstance(responder_hello, Hello)
assert isinstance(initiator_hello, Hello)
