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