Reference client for Bitmessage: a P2P encrypted decentralised communication protocol:
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"""
SSL/TLS negotiation.
"""
import os
import socket
import ssl
import sys
from debug import logger
from network.advanceddispatcher import AdvancedDispatcher
import network.asyncore_pollchoose as asyncore
import paths
import protocol
class TLSDispatcher(AdvancedDispatcher):
def __init__(self, address=None, sock=None,
certfile=None, keyfile=None, server_side=False, ciphers=protocol.sslProtocolCiphers):
self.want_read = self.want_write = True
if certfile is None:
self.certfile = os.path.join(paths.codePath(), 'sslkeys', 'cert.pem')
else:
self.certfile = certfile
if keyfile is None:
self.keyfile = os.path.join(paths.codePath(), 'sslkeys', 'key.pem')
else:
self.keyfile = keyfile
self.server_side = server_side
self.ciphers = ciphers
self.tlsStarted = False
self.tlsDone = False
self.isSSL = False
def state_tls_init(self):
self.isSSL = True
self.tlsStarted = True
# Once the connection has been established, it's safe to wrap the
# socket.
if sys.version_info >= (2,7,9):
context = ssl.create_default_context(purpose = ssl.Purpose.SERVER_AUTH if self.server_side else ssl.Purpose.CLIENT_AUTH)
context.set_ciphers(self.ciphers)
context.set_ecdh_curve("secp256k1")
context.check_hostname = False
context.verify_mode = ssl.CERT_NONE
# also exclude TLSv1 and TLSv1.1 in the future
context.options = ssl.OP_ALL | ssl.OP_NO_SSLv2 | ssl.OP_NO_SSLv3 | ssl.OP_SINGLE_ECDH_USE | ssl.OP_CIPHER_SERVER_PREFERENCE
self.sslSocket = context.wrap_socket(self.socket, server_side = self.server_side, do_handshake_on_connect=False)
else:
self.sslSocket = ssl.wrap_socket(self.socket,
server_side=self.server_side,
ssl_version=protocol.sslProtocolVersion,
certfile=self.certfile,
keyfile=self.keyfile,
ciphers=self.ciphers,
do_handshake_on_connect=False)
self.sslSocket.setblocking(0)
self.want_read = self.want_write = True
self.set_state("bm_header")
# if hasattr(self.socket, "context"):
# self.socket.context.set_ecdh_curve("secp256k1")
def writable(self):
try:
if self.tlsStarted and not self.tlsDone and len(self.write_buf) == 0 and self.writeQueue.empty():
#print "tls writable, %r" % (self.want_write)
return self.want_write
else:
return AdvancedDispatcher.writable(self)
except AttributeError:
return AdvancedDispatcher.writable(self)
def readable(self):
try:
if self.tlsStarted and not self.tlsDone and len(self.write_buf) == 0 and self.writeQueue.empty():
#print "tls readable, %r" % (self.want_read)
return self.want_read
else:
return AdvancedDispatcher.readable(self)
except AttributeError:
return AdvancedDispatcher.readable(self)
def handle_read(self):
try:
# wait for write buffer flush
if self.tlsStarted and not self.tlsDone and len(self.write_buf) == 0 and self.writeQueue.empty():
#print "handshaking (read)"
self.tls_handshake()
else:
#print "not handshaking (read)"
return AdvancedDispatcher.handle_read(self)
except AttributeError:
return AdvancedDispatcher.handle_read(self)
def handle_write(self):
try:
# wait for write buffer flush
if self.tlsStarted and not self.tlsDone and len(self.write_buf) == 0 and self.writeQueue.empty():
#print "handshaking (write)"
self.tls_handshake()
else:
#print "not handshaking (write)"
return AdvancedDispatcher.handle_write(self)
except AttributeError:
return AdvancedDispatcher.handle_read(self)
def tls_handshake(self):
# wait for flush
if len(self.write_buf) > 0:
return False
# Perform the handshake.
try:
#print "handshaking (internal)"
self.sslSocket.do_handshake()
except ssl.SSLError, err:
#print "%s:%i: handshake fail" % (self.destination.host, self.destination.port)
self.want_read = self.want_write = False
if err.args[0] == ssl.SSL_ERROR_WANT_READ:
#print "want read"
self.want_read = True
if err.args[0] == ssl.SSL_ERROR_WANT_WRITE:
#print "want write"
self.want_write = True
if not (self.want_write or self.want_read):
raise
else:
logger.debug("%s:%i: TLS handshake success%s", self.destination.host, self.destination.port, ", TLS protocol version: %s" % (self.sslSocket.version()) if sys.version_info >= (2, 7, 9) else "")
# The handshake has completed, so remove this channel and...
self.del_channel()
self.set_socket(self.sslSocket)
self.tlsDone = True
self.set_state("bm_header")
self.set_connection_fully_established()
return False