PySecretHandshake/secret_handshake/network.py
2023-10-31 07:34:57 +01:00

196 lines
5.9 KiB
Python

# Copyright (c) 2017 PySecretHandshake contributors (see AUTHORS for more details)
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
"""Networking functionality"""
import asyncio
from .boxstream import get_stream_pair
from .crypto import SHSClientCrypto, SHSServerCrypto
class SHSClientException(Exception):
"""Base exception class for client errors"""
class SHSDuplexStream:
"""SHS duplex stream"""
def __init__(self):
self.write_stream = None
self.read_stream = None
self.is_connected = False
def write(self, data):
"""Write data to the write stream"""
self.write_stream.write(data)
async def read(self):
"""Read data from the read stream"""
return await self.read_stream.read()
def close(self):
"""Close the duplex stream"""
self.write_stream.close()
self.read_stream.close()
self.is_connected = False
def __aiter__(self):
return self
async def __anext__(self):
msg = await self.read()
if msg is None:
raise StopAsyncIteration()
return msg
class SHSEndpoint:
"""SHS endpoint"""
def __init__(self):
self._on_connect = None
self.crypto = None
def on_connect(self, cb):
"""Set the function to be called when a new connection arrives"""
self._on_connect = cb
def disconnect(self):
"""Disconnect the endpoint"""
raise NotImplementedError
class SHSServer(SHSEndpoint):
"""SHS server"""
def __init__(self, host, port, server_kp, application_key=None):
super().__init__()
self.host = host
self.port = port
self.crypto = SHSServerCrypto(server_kp, application_key=application_key)
self.connections = []
async def _handshake(self, reader, writer):
data = await reader.readexactly(64)
if not self.crypto.verify_challenge(data):
raise SHSClientException("Client challenge is not valid")
writer.write(self.crypto.generate_challenge())
data = await reader.readexactly(112)
if not self.crypto.verify_client_auth(data):
raise SHSClientException("Client auth is not valid")
writer.write(self.crypto.generate_accept())
async def handle_connection(self, reader, writer):
"""Handle incoming connections"""
self.crypto.clean()
await self._handshake(reader, writer)
keys = self.crypto.get_box_keys()
self.crypto.clean()
conn = SHSServerConnection.from_byte_streams(reader, writer, **keys)
self.connections.append(conn)
if self._on_connect:
asyncio.ensure_future(self._on_connect(conn))
async def listen(self):
"""Listen for connections"""
await asyncio.start_server(self.handle_connection, self.host, self.port)
def disconnect(self):
for connection in self.connections:
connection.close()
class SHSServerConnection(SHSDuplexStream):
"""SHS server connection"""
def __init__(self, read_stream, write_stream):
super().__init__()
self.read_stream = read_stream
self.write_stream = write_stream
@classmethod
def from_byte_streams(cls, reader, writer, **keys):
"""Create a server connection from an existing byte stream"""
reader, writer = get_stream_pair(reader, writer, **keys)
return cls(reader, writer)
class SHSClient(SHSDuplexStream, SHSEndpoint):
"""SHS client"""
def __init__( # pylint: disable=too-many-arguments
self, host, port, client_kp, server_pub_key, ephemeral_key=None, application_key=None
):
SHSDuplexStream.__init__(self)
SHSEndpoint.__init__(self)
self.host = host
self.port = port
self.writer = None
self.crypto = SHSClientCrypto(
client_kp, server_pub_key, ephemeral_key=ephemeral_key, application_key=application_key
)
async def _handshake(self, reader, writer):
writer.write(self.crypto.generate_challenge())
data = await reader.readexactly(64)
if not self.crypto.verify_server_challenge(data):
raise SHSClientException("Server challenge is not valid")
writer.write(self.crypto.generate_client_auth())
data = await reader.readexactly(80)
if not self.crypto.verify_server_accept(data):
raise SHSClientException("Server accept is not valid")
async def open(self):
"""Open the TCP connection"""
reader, writer = await asyncio.open_connection(self.host, self.port)
await self._handshake(reader, writer)
keys = self.crypto.get_box_keys()
self.crypto.clean()
self.read_stream, self.write_stream = get_stream_pair(reader, writer, **keys)
self.writer = writer
self.is_connected = True
if self._on_connect:
await self._on_connect()
def disconnect(self):
self.close()