py-libp2p/libp2p/security/noise/patterns.py
2020-08-25 15:59:22 -06:00

185 lines
7.0 KiB
Python

from abc import ABC, abstractmethod
from cryptography.hazmat.primitives import serialization
from noise.backends.default.keypairs import KeyPair as NoiseKeyPair
from noise.connection import Keypair as NoiseKeypairEnum
from noise.connection import NoiseConnection as NoiseState
from libp2p.crypto.ed25519 import Ed25519PublicKey
from libp2p.crypto.keys import PrivateKey, PublicKey
from libp2p.network.connection.raw_connection_interface import IRawConnection
from libp2p.peer.id import ID
from libp2p.security.secure_conn_interface import ISecureConn
from libp2p.security.secure_session import SecureSession
from .exceptions import (
HandshakeHasNotFinished,
InvalidSignature,
NoiseStateError,
PeerIDMismatchesPubkey,
)
from .io import NoiseHandshakeReadWriter, NoiseTransportReadWriter
from .messages import (
NoiseHandshakePayload,
make_handshake_payload_sig,
verify_handshake_payload_sig,
)
class IPattern(ABC):
@abstractmethod
async def handshake_inbound(self, conn: IRawConnection) -> ISecureConn:
...
@abstractmethod
async def handshake_outbound(
self, conn: IRawConnection, remote_peer: ID
) -> ISecureConn:
...
class BasePattern(IPattern):
protocol_name: bytes
noise_static_key: PrivateKey
local_peer: ID
libp2p_privkey: PrivateKey
early_data: bytes
def create_noise_state(self) -> NoiseState:
noise_state = NoiseState.from_name(self.protocol_name)
noise_state.set_keypair_from_private_bytes(
NoiseKeypairEnum.STATIC, self.noise_static_key.to_bytes()
)
return noise_state
def make_handshake_payload(self) -> NoiseHandshakePayload:
signature = make_handshake_payload_sig(
self.libp2p_privkey, self.noise_static_key.get_public_key()
)
return NoiseHandshakePayload(self.libp2p_privkey.get_public_key(), signature)
class PatternXX(BasePattern):
def __init__(
self,
local_peer: ID,
libp2p_privkey: PrivateKey,
noise_static_key: PrivateKey,
early_data: bytes = None,
) -> None:
self.protocol_name = b"Noise_XX_25519_ChaChaPoly_SHA256"
self.local_peer = local_peer
self.libp2p_privkey = libp2p_privkey
self.noise_static_key = noise_static_key
self.early_data = early_data
async def handshake_inbound(self, conn: IRawConnection) -> ISecureConn:
noise_state = self.create_noise_state()
noise_state.set_as_responder()
noise_state.start_handshake()
handshake_state = noise_state.noise_protocol.handshake_state
read_writer = NoiseHandshakeReadWriter(conn, noise_state)
# Consume msg#1.
await read_writer.read_msg()
# Send msg#2, which should include our handshake payload.
our_payload = self.make_handshake_payload()
msg_2 = our_payload.serialize()
await read_writer.write_msg(msg_2)
# Receive and consume msg#3.
msg_3 = await read_writer.read_msg()
peer_handshake_payload = NoiseHandshakePayload.deserialize(msg_3)
if handshake_state.rs is None:
raise NoiseStateError(
"something is wrong in the underlying noise `handshake_state`: "
"we received and consumed msg#3, which should have included the"
" remote static public key, but it is not present in the handshake_state"
)
remote_pubkey = self._get_pubkey_from_noise_keypair(handshake_state.rs)
if not verify_handshake_payload_sig(peer_handshake_payload, remote_pubkey):
raise InvalidSignature
remote_peer_id_from_pubkey = ID.from_pubkey(peer_handshake_payload.id_pubkey)
if not noise_state.handshake_finished:
raise HandshakeHasNotFinished(
"handshake is done but it is not marked as finished in `noise_state`"
)
transport_read_writer = NoiseTransportReadWriter(conn, noise_state)
return SecureSession(
local_peer=self.local_peer,
local_private_key=self.libp2p_privkey,
remote_peer=remote_peer_id_from_pubkey,
remote_permanent_pubkey=remote_pubkey,
is_initiator=False,
conn=transport_read_writer,
)
async def handshake_outbound(
self, conn: IRawConnection, remote_peer: ID
) -> ISecureConn:
noise_state = self.create_noise_state()
read_writer = NoiseHandshakeReadWriter(conn, noise_state)
noise_state.set_as_initiator()
noise_state.start_handshake()
handshake_state = noise_state.noise_protocol.handshake_state
# Send msg#1, which is *not* encrypted.
msg_1 = b""
await read_writer.write_msg(msg_1)
# Read msg#2 from the remote, which contains the public key of the peer.
msg_2 = await read_writer.read_msg()
peer_handshake_payload = NoiseHandshakePayload.deserialize(msg_2)
if handshake_state.rs is None:
raise NoiseStateError(
"something is wrong in the underlying noise `handshake_state`: "
"we received and consumed msg#3, which should have included the"
" remote static public key, but it is not present in the handshake_state"
)
remote_pubkey = self._get_pubkey_from_noise_keypair(handshake_state.rs)
if not verify_handshake_payload_sig(peer_handshake_payload, remote_pubkey):
raise InvalidSignature
remote_peer_id_from_pubkey = ID.from_pubkey(peer_handshake_payload.id_pubkey)
if remote_peer_id_from_pubkey != remote_peer:
raise PeerIDMismatchesPubkey(
"peer id does not correspond to the received pubkey: "
f"remote_peer={remote_peer}, "
f"remote_peer_id_from_pubkey={remote_peer_id_from_pubkey}"
)
# Send msg#3, which includes our encrypted payload and our noise static key.
our_payload = self.make_handshake_payload()
msg_3 = our_payload.serialize()
await read_writer.write_msg(msg_3)
if not noise_state.handshake_finished:
raise HandshakeHasNotFinished(
"handshake is done but it is not marked as finished in `noise_state`"
)
transport_read_writer = NoiseTransportReadWriter(conn, noise_state)
return SecureSession(
local_peer=self.local_peer,
local_private_key=self.libp2p_privkey,
remote_peer=remote_peer_id_from_pubkey,
remote_permanent_pubkey=remote_pubkey,
is_initiator=True,
conn=transport_read_writer,
)
@staticmethod
def _get_pubkey_from_noise_keypair(key_pair: NoiseKeyPair) -> PublicKey:
# Use `Ed25519PublicKey` since 25519 is used in our pattern.
raw_bytes = key_pair.public.public_bytes(
# ignore "'Type[...]' has no attribute 'Raw'"
serialization.Encoding.Raw, # type: ignore
serialization.PublicFormat.Raw, # type: ignore
)
return Ed25519PublicKey.from_bytes(raw_bytes)