90 lines
3.1 KiB
Python
90 lines
3.1 KiB
Python
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"""
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SSL/TLS negotiation.
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"""
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import asyncore
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import socket
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import ssl
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class TLSHandshake(asyncore.dispatcher):
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"""
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Negotiates a SSL/TLS connection before handing itself spawning a
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dispatcher that can deal with the overlying protocol as soon as the
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handshake has been completed.
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`handoff` is a function/method called when the handshake has completed.
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`address` is a tuple consisting of hostname/address and port to connect to
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if nothing is passed in `sock`, which can take an already-connected socket.
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`certfile` can take a path to a certificate bundle, and `server_side`
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indicates whether the socket is intended to be a server-side or client-side
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socket.
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"""
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def __init__(self, address=None, sock=None,
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certfile=None, keyfile=None, server_side=False, ciphers=None, init_parent=True):
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if not hasattr(self, '_map'):
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asyncore.dispatcher.__init__(self, sock)
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self.want_read = self.want_write = True
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self.certfile = certfile
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self.keyfile = keyfile
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self.server_side = server_side
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self.ciphers = ciphers
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self.tlsDone = False
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if sock is None:
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self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
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# logger.info('Connecting to %s%d', address[0], address[1])
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self.connect(address)
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elif self.connected:
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# Initiate the handshake for an already-connected socket.
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self.handle_connect()
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def handle_connect(self):
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# Once the connection has been established, it's safe to wrap the
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# socket.
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self.sslSocket = ssl.wrap_socket(self.socket,
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server_side=self.server_side,
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ssl_version=ssl.PROTOCOL_TLSv1,
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certfile=self.certfile,
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keyfile=self.keyfile,
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ciphers=self.ciphers,
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do_handshake_on_connect=False)
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self.sslSocket.setblocking(0)
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self.want_read = self.want_write = True
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# if hasattr(self.socket, "context"):
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# self.socket.context.set_ecdh_curve("secp256k1")
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def writable(self):
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return self.want_write
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def readable(self):
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return self.want_read
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def handle_read(self):
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if not self.tlsDone:
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self._handshake()
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def handle_write(self):
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if not self.tlsDone:
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self._handshake()
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def _handshake(self):
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"""
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Perform the handshake.
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"""
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try:
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self.sslSocket.do_handshake()
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except ssl.SSLError, err:
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self.want_read = self.want_write = False
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if err.args[0] == ssl.SSL_ERROR_WANT_READ:
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self.want_read = True
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elif err.args[0] == ssl.SSL_ERROR_WANT_WRITE:
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self.want_write = True
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else:
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raise
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else:
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# The handshake has completed, so remove this channel and...
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self.del_channel()
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self.set_socket(self.sslSocket)
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self.tlsDone = True
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