py-libp2p/libp2p/security/insecure/transport.py
2020-02-06 10:39:54 +08:00

141 lines
5.6 KiB
Python

from typing import Optional
from libp2p.crypto.exceptions import MissingDeserializerError
from libp2p.crypto.keys import PrivateKey, PublicKey
from libp2p.crypto.pb import crypto_pb2
from libp2p.crypto.serialization import deserialize_public_key
from libp2p.io.abc import ReadWriteCloser
from libp2p.network.connection.exceptions import RawConnError
from libp2p.network.connection.raw_connection_interface import IRawConnection
from libp2p.peer.id import ID
from libp2p.security.base_session import BaseSession
from libp2p.security.base_transport import BaseSecureTransport
from libp2p.security.exceptions import HandshakeFailure
from libp2p.security.secure_conn_interface import ISecureConn
from libp2p.typing import TProtocol
from libp2p.utils import encode_fixedint_prefixed, read_fixedint_prefixed
from .pb import plaintext_pb2
# Reference: https://github.com/libp2p/go-libp2p-core/blob/master/sec/insecure/insecure.go
PLAINTEXT_PROTOCOL_ID = TProtocol("/plaintext/2.0.0")
class InsecureSession(BaseSession):
def __init__(
self,
local_peer: ID,
local_private_key: PrivateKey,
conn: ReadWriteCloser,
is_initiator: bool,
peer_id: Optional[ID] = None,
) -> None:
super().__init__(local_peer, local_private_key, is_initiator, peer_id)
self.conn = conn
async def write(self, data: bytes) -> int:
await self.conn.write(data)
return len(data)
async def read(self, n: int = None) -> bytes:
return await self.conn.read(n)
async def close(self) -> None:
await self.conn.close()
async def run_handshake(self) -> None:
"""Raise `HandshakeFailure` when handshake failed."""
msg = make_exchange_message(self.local_private_key.get_public_key())
msg_bytes = msg.SerializeToString()
encoded_msg_bytes = encode_fixedint_prefixed(msg_bytes)
try:
await self.write(encoded_msg_bytes)
except RawConnError as e:
raise HandshakeFailure("connection closed") from e
try:
remote_msg_bytes = await read_fixedint_prefixed(self.conn)
except RawConnError as e:
raise HandshakeFailure("connection closed") from e
remote_msg = plaintext_pb2.Exchange()
remote_msg.ParseFromString(remote_msg_bytes)
received_peer_id = ID(remote_msg.id)
# Verify if the receive `ID` matches the one we originally initialize the session.
# We only need to check it when we are the initiator, because only in that condition
# we possibly knows the `ID` of the remote.
if self.is_initiator and self.remote_peer_id != received_peer_id:
raise HandshakeFailure(
"remote peer sent unexpected peer ID. "
f"expected={self.remote_peer_id} received={received_peer_id}"
)
# Verify if the given `pubkey` matches the given `peer_id`
try:
received_pubkey = deserialize_public_key(
remote_msg.pubkey.SerializeToString()
)
except ValueError as e:
raise HandshakeFailure(
f"unknown `key_type` of remote_msg.pubkey={remote_msg.pubkey}"
) from e
except MissingDeserializerError as error:
raise HandshakeFailure() from error
peer_id_from_received_pubkey = ID.from_pubkey(received_pubkey)
if peer_id_from_received_pubkey != received_peer_id:
raise HandshakeFailure(
"peer id and pubkey from the remote mismatch: "
f"received_peer_id={received_peer_id}, remote_pubkey={received_pubkey}, "
f"peer_id_from_received_pubkey={peer_id_from_received_pubkey}"
)
# Nothing is wrong. Store the `pubkey` and `peer_id` in the session.
self.remote_permanent_pubkey = received_pubkey
# Only need to set peer's id when we don't know it before,
# i.e. we are not the connection initiator.
if not self.is_initiator:
self.remote_peer_id = received_peer_id
# TODO: Store `pubkey` and `peer_id` to `PeerStore`
class InsecureTransport(BaseSecureTransport):
"""``InsecureTransport`` provides the "identity" upgrader for a
``IRawConnection``, i.e. the upgraded transport does not add any additional
security."""
async def secure_inbound(self, conn: IRawConnection) -> ISecureConn:
"""
Secure the connection, either locally or by communicating with opposing
node via conn, for an inbound connection (i.e. we are not the
initiator)
:return: secure connection object (that implements secure_conn_interface)
"""
session = InsecureSession(self.local_peer, self.local_private_key, conn, False)
await session.run_handshake()
return session
async def secure_outbound(self, conn: IRawConnection, peer_id: ID) -> ISecureConn:
"""
Secure the connection, either locally or by communicating with opposing
node via conn, for an inbound connection (i.e. we are the initiator)
:return: secure connection object (that implements secure_conn_interface)
"""
session = InsecureSession(
self.local_peer, self.local_private_key, conn, True, peer_id
)
await session.run_handshake()
return session
def make_exchange_message(pubkey: PublicKey) -> plaintext_pb2.Exchange:
pubkey_pb = crypto_pb2.PublicKey(
key_type=pubkey.get_type().value, data=pubkey.to_bytes()
)
id_bytes = ID.from_pubkey(pubkey).to_bytes()
return plaintext_pb2.Exchange(id=id_bytes, pubkey=pubkey_pb)