py-libp2p/libp2p/security/noise/io.py
mhchia 3c2e835725
Security: SecureSession
Make security sessions(secio, noise) share the same implementation
`BaseSession` to avoid duplicate implementation of buffered read.
2020-02-28 15:49:59 +08:00

92 lines
3.3 KiB
Python

from typing import cast
from noise.connection import NoiseConnection as NoiseState
from libp2p.io.abc import EncryptedMsgReadWriter, MsgReadWriteCloser, ReadWriteCloser
from libp2p.io.msgio import BaseMsgReadWriter, encode_msg_with_length
from libp2p.network.connection.raw_connection_interface import IRawConnection
SIZE_NOISE_MESSAGE_LEN = 2
MAX_NOISE_MESSAGE_LEN = 2 ** (8 * SIZE_NOISE_MESSAGE_LEN) - 1
SIZE_NOISE_MESSAGE_BODY_LEN = 2
MAX_NOISE_MESSAGE_BODY_LEN = MAX_NOISE_MESSAGE_LEN - SIZE_NOISE_MESSAGE_BODY_LEN
BYTE_ORDER = "big"
# | Noise packet |
# < 2 bytes -><- 65535 ->
# | noise msg len | noise msg |
# | body len | body | padding |
# <-2 bytes-><- max=65533 bytes ->
class NoisePacketReadWriter(BaseMsgReadWriter):
size_len_bytes = SIZE_NOISE_MESSAGE_LEN
def encode_msg_body(msg_body: bytes) -> bytes:
encoded_msg_body = encode_msg_with_length(msg_body, SIZE_NOISE_MESSAGE_BODY_LEN)
if len(encoded_msg_body) > MAX_NOISE_MESSAGE_BODY_LEN:
raise ValueError(
f"msg_body is too long: {len(msg_body)}, "
f"maximum={MAX_NOISE_MESSAGE_BODY_LEN}"
)
# NOTE: Improvements:
# 1. Senders *SHOULD* use a source of random data to populate the padding field.
# 2. and *may* use any length of padding that does not cause the total length of
# the Noise message to exceed 65535 bytes.
# Ref: https://github.com/libp2p/specs/tree/master/noise#encrypted-payloads
return encoded_msg_body # + padding
def decode_msg_body(noise_msg: bytes) -> bytes:
len_body = int.from_bytes(noise_msg[:SIZE_NOISE_MESSAGE_BODY_LEN], BYTE_ORDER)
# Just ignore the padding
return noise_msg[
SIZE_NOISE_MESSAGE_BODY_LEN : (SIZE_NOISE_MESSAGE_BODY_LEN + len_body)
]
class BaseNoiseMsgReadWriter(EncryptedMsgReadWriter):
"""
The base implementation of noise message reader/writer.
`encrypt` and `decrypt` are not implemented here, which should be
implemented by the subclasses.
"""
read_writer: MsgReadWriteCloser
noise_state: NoiseState
def __init__(self, conn: IRawConnection, noise_state: NoiseState) -> None:
self.read_writer = NoisePacketReadWriter(cast(ReadWriteCloser, conn))
self.noise_state = noise_state
async def write_msg(self, data: bytes) -> None:
noise_msg = encode_msg_body(data)
data_encrypted = self.encrypt(noise_msg)
await self.read_writer.write_msg(data_encrypted)
async def read_msg(self) -> bytes:
noise_msg_encrypted = await self.read_writer.read_msg()
noise_msg = self.decrypt(noise_msg_encrypted)
return decode_msg_body(noise_msg)
async def close(self) -> None:
await self.read_writer.close()
class NoiseHandshakeReadWriter(BaseNoiseMsgReadWriter):
def encrypt(self, data: bytes) -> bytes:
return self.noise_state.write_message(data)
def decrypt(self, data: bytes) -> bytes:
return self.noise_state.read_message(data)
class NoiseTransportReadWriter(BaseNoiseMsgReadWriter):
def encrypt(self, data: bytes) -> bytes:
return self.noise_state.encrypt(data)
def decrypt(self, data: bytes) -> bytes:
return self.noise_state.decrypt(data)