Your IP : 3.141.2.157
"""
Make Twisted use M2Crypto for SSL
Copyright (c) 2004-2007 Open Source Applications Foundation.
All rights reserved.
"""
__all__ = ['connectSSL', 'connectTCP', 'listenSSL', 'listenTCP',
'TLSProtocolWrapper']
import twisted.protocols.policies as policies
import twisted.internet.reactor
from twisted.protocols.policies import ProtocolWrapper
from twisted.internet.interfaces import ITLSTransport
from zope.interface import implements
import M2Crypto # for M2Crypto.BIO.BIOError
from M2Crypto import m2, X509
from M2Crypto.SSL import Checker
def _alwaysSucceedsPostConnectionCheck(peerX509, expectedHost):
return 1
def connectSSL(host, port, factory, contextFactory, timeout=30,
bindAddress=None,
reactor=twisted.internet.reactor,
postConnectionCheck=Checker.Checker()):
"""
A convenience function to start an SSL/TLS connection using Twisted.
See IReactorSSL interface in Twisted.
"""
wrappingFactory = policies.WrappingFactory(factory)
wrappingFactory.protocol = lambda factory, wrappedProtocol: \
TLSProtocolWrapper(factory,
wrappedProtocol,
startPassThrough=0,
client=1,
contextFactory=contextFactory,
postConnectionCheck=postConnectionCheck)
return reactor.connectTCP(host, port, wrappingFactory, timeout, bindAddress)
def connectTCP(host, port, factory, timeout=30, bindAddress=None,
reactor=twisted.internet.reactor,
postConnectionCheck=Checker.Checker()):
"""
A convenience function to start a TCP connection using Twisted.
NOTE: You must call startTLS(ctx) to go into SSL/TLS mode.
See IReactorTCP interface in Twisted.
"""
wrappingFactory = policies.WrappingFactory(factory)
wrappingFactory.protocol = lambda factory, wrappedProtocol: \
TLSProtocolWrapper(factory,
wrappedProtocol,
startPassThrough=1,
client=1,
contextFactory=None,
postConnectionCheck=postConnectionCheck)
return reactor.connectTCP(host, port, wrappingFactory, timeout, bindAddress)
def listenSSL(port, factory, contextFactory, backlog=5, interface='',
reactor=twisted.internet.reactor,
postConnectionCheck=_alwaysSucceedsPostConnectionCheck):
"""
A convenience function to listen for SSL/TLS connections using Twisted.
See IReactorSSL interface in Twisted.
"""
wrappingFactory = policies.WrappingFactory(factory)
wrappingFactory.protocol = lambda factory, wrappedProtocol: \
TLSProtocolWrapper(factory,
wrappedProtocol,
startPassThrough=0,
client=0,
contextFactory=contextFactory,
postConnectionCheck=postConnectionCheck)
return reactor.listenTCP(port, wrappingFactory, backlog, interface)
def listenTCP(port, factory, backlog=5, interface='',
reactor=twisted.internet.reactor,
postConnectionCheck=None):
"""
A convenience function to listen for TCP connections using Twisted.
NOTE: You must call startTLS(ctx) to go into SSL/TLS mode.
See IReactorTCP interface in Twisted.
"""
wrappingFactory = policies.WrappingFactory(factory)
wrappingFactory.protocol = lambda factory, wrappedProtocol: \
TLSProtocolWrapper(factory,
wrappedProtocol,
startPassThrough=1,
client=0,
contextFactory=None,
postConnectionCheck=postConnectionCheck)
return reactor.listenTCP(port, wrappingFactory, backlog, interface)
class _BioProxy:
"""
The purpose of this class is to eliminate the __del__ method from
TLSProtocolWrapper, and thus letting it be garbage collected.
"""
m2_bio_free_all = m2.bio_free_all
def __init__(self, bio):
self.bio = bio
def _ptr(self):
return self.bio
def __del__(self):
if self.bio is not None:
self.m2_bio_free_all(self.bio)
class _SSLProxy:
"""
The purpose of this class is to eliminate the __del__ method from
TLSProtocolWrapper, and thus letting it be garbage collected.
"""
m2_ssl_free = m2.ssl_free
def __init__(self, ssl):
self.ssl = ssl
def _ptr(self):
return self.ssl
def __del__(self):
if self.ssl is not None:
self.m2_ssl_free(self.ssl)
class TLSProtocolWrapper(ProtocolWrapper):
"""
A SSL/TLS protocol wrapper to be used with Twisted. Typically
you would not use this class directly. Use connectTCP,
connectSSL, listenTCP, listenSSL functions defined above,
which will hook in this class.
"""
implements(ITLSTransport)
def __init__(self, factory, wrappedProtocol, startPassThrough, client,
contextFactory, postConnectionCheck):
"""
@param factory:
@param wrappedProtocol:
@param startPassThrough: If true we won't encrypt at all. Need to
call startTLS() later to switch to SSL/TLS.
@param client: True if this should be a client protocol.
@param contextFactory: Factory that creates SSL.Context objects.
The called function is getContext().
@param postConnectionCheck: The post connection check callback that
will be called just after connection has
been established but before any real data
has been exchanged. The first argument to
this function is an X509 object, the second
is the expected host name string.
"""
#ProtocolWrapper.__init__(self, factory, wrappedProtocol)
#XXX: Twisted 2.0 has a new addition where the wrappingFactory is
# set as the factory of the wrappedProtocol. This is an issue
# as the wrap should be transparent. What we want is
# the factory of the wrappedProtocol to be the wrappedFactory and
# not the outer wrappingFactory. This is how it was implemented in
# Twisted 1.3
self.factory = factory
self.wrappedProtocol = wrappedProtocol
# wrappedProtocol == client/server instance
# factory.wrappedFactory == client/server factory
self.data = '' # Clear text to encrypt and send
self.encrypted = '' # Encrypted data we need to decrypt and pass on
self.tlsStarted = 0 # SSL/TLS mode or pass through
self.checked = 0 # Post connection check done or not
self.isClient = client
self.helloDone = 0 # True when hello has been sent
if postConnectionCheck is None:
self.postConnectionCheck = _alwaysSucceedsPostConnectionCheck
else:
self.postConnectionCheck = postConnectionCheck
if not startPassThrough:
self.startTLS(contextFactory.getContext())
def clear(self):
"""
Clear this instance, after which it is ready for reuse.
"""
if getattr(self, 'tlsStarted', 0):
self.sslBio = None
self.ssl = None
self.internalBio = None
self.networkBio = None
self.data = ''
self.encrypted = ''
self.tlsStarted = 0
self.checked = 0
self.isClient = 1
self.helloDone = 0
# We can reuse self.ctx and it will be deleted automatically
# when this instance dies
def startTLS(self, ctx):
"""
Start SSL/TLS. If this is not called, this instance just passes data
through untouched.
"""
# NOTE: This method signature must match the startTLS() method Twisted
# expects transports to have. This will be called automatically
# by Twisted in STARTTLS situations, for example with SMTP.
if self.tlsStarted:
raise Exception, 'TLS already started'
self.ctx = ctx
self.internalBio = m2.bio_new(m2.bio_s_bio())
m2.bio_set_write_buf_size(self.internalBio, 0)
self.networkBio = _BioProxy(m2.bio_new(m2.bio_s_bio()))
m2.bio_set_write_buf_size(self.networkBio._ptr(), 0)
m2.bio_make_bio_pair(self.internalBio, self.networkBio._ptr())
self.sslBio = _BioProxy(m2.bio_new(m2.bio_f_ssl()))
self.ssl = _SSLProxy(m2.ssl_new(self.ctx.ctx))
if self.isClient:
m2.ssl_set_connect_state(self.ssl._ptr())
else:
m2.ssl_set_accept_state(self.ssl._ptr())
m2.ssl_set_bio(self.ssl._ptr(), self.internalBio, self.internalBio)
m2.bio_set_ssl(self.sslBio._ptr(), self.ssl._ptr(), m2.bio_noclose)
# Need this for writes that are larger than BIO pair buffers
mode = m2.ssl_get_mode(self.ssl._ptr())
m2.ssl_set_mode(self.ssl._ptr(),
mode |
m2.SSL_MODE_ENABLE_PARTIAL_WRITE |
m2.SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER)
self.tlsStarted = 1
def write(self, data):
if not self.tlsStarted:
ProtocolWrapper.write(self, data)
return
try:
encryptedData = self._encrypt(data)
ProtocolWrapper.write(self, encryptedData)
self.helloDone = 1
except M2Crypto.BIO.BIOError, e:
# See http://www.openssl.org/docs/apps/verify.html#DIAGNOSTICS
# for the error codes returned by SSL_get_verify_result.
e.args = (m2.ssl_get_verify_result(self.ssl._ptr()), e.args[0])
raise e
def writeSequence(self, data):
if not self.tlsStarted:
ProtocolWrapper.writeSequence(self, ''.join(data))
return
self.write(''.join(data))
def loseConnection(self):
# XXX Do we need to do m2.ssl_shutdown(self.ssl._ptr())?
ProtocolWrapper.loseConnection(self)
def connectionMade(self):
ProtocolWrapper.connectionMade(self)
if self.tlsStarted and self.isClient and not self.helloDone:
self._clientHello()
def dataReceived(self, data):
if not self.tlsStarted:
ProtocolWrapper.dataReceived(self, data)
return
self.encrypted += data
try:
while 1:
decryptedData = self._decrypt()
self._check()
encryptedData = self._encrypt()
ProtocolWrapper.write(self, encryptedData)
ProtocolWrapper.dataReceived(self, decryptedData)
if decryptedData == '' and encryptedData == '':
break
except M2Crypto.BIO.BIOError, e:
# See http://www.openssl.org/docs/apps/verify.html#DIAGNOSTICS
# for the error codes returned by SSL_get_verify_result.
e.args = (m2.ssl_get_verify_result(self.ssl._ptr()), e.args[0])
raise e
def connectionLost(self, reason):
self.clear()
ProtocolWrapper.connectionLost(self, reason)
def _check(self):
if not self.checked and m2.ssl_is_init_finished(self.ssl._ptr()):
x509 = m2.ssl_get_peer_cert(self.ssl._ptr())
if x509 is not None:
x509 = X509.X509(x509, 1)
if self.isClient:
host = self.transport.addr[0]
else:
host = self.transport.getPeer().host
if not self.postConnectionCheck(x509, host):
raise Checker.SSLVerificationError, 'post connection check'
self.checked = 1
def _clientHello(self):
try:
# We rely on OpenSSL implicitly starting with client hello
# when we haven't yet established an SSL connection
encryptedData = self._encrypt(clientHello=1)
ProtocolWrapper.write(self, encryptedData)
self.helloDone = 1
except M2Crypto.BIO.BIOError, e:
# See http://www.openssl.org/docs/apps/verify.html#DIAGNOSTICS
# for the error codes returned by SSL_get_verify_result.
e.args = (m2.ssl_get_verify_result(self.ssl._ptr()), e.args[0])
raise e
def _encrypt(self, data='', clientHello=0):
# XXX near mirror image of _decrypt - refactor
encryptedData = ''
self.data += data
# Optimizations to reduce attribute accesses
sslBioPtr = self.sslBio._ptr()
networkBio = self.networkBio._ptr()
m2bio_ctrl_get_write_guarantee = m2.bio_ctrl_get_write_guarantee
m2bio_write = m2.bio_write
m2bio_should_retry = m2.bio_should_retry
m2bio_ctrl_pending = m2.bio_ctrl_pending
m2bio_read = m2.bio_read
while 1:
g = m2bio_ctrl_get_write_guarantee(sslBioPtr)
if g > 0 and self.data != '' or clientHello:
r = m2bio_write(sslBioPtr, self.data)
if r <= 0:
assert(m2bio_should_retry(sslBioPtr))
else:
assert(self.checked)
self.data = self.data[r:]
pending = m2bio_ctrl_pending(networkBio)
if pending:
d = m2bio_read(networkBio, pending)
if d is not None: # This is strange, but d can be None
encryptedData += d
else:
assert(m2bio_should_retry(networkBio))
else:
break
return encryptedData
def _decrypt(self, data=''):
# XXX near mirror image of _encrypt - refactor
self.encrypted += data
decryptedData = ''
# Optimizations to reduce attribute accesses
sslBioPtr = self.sslBio._ptr()
networkBio = self.networkBio._ptr()
m2bio_ctrl_get_write_guarantee = m2.bio_ctrl_get_write_guarantee
m2bio_write = m2.bio_write
m2bio_should_retry = m2.bio_should_retry
m2bio_ctrl_pending = m2.bio_ctrl_pending
m2bio_read = m2.bio_read
while 1:
g = m2bio_ctrl_get_write_guarantee(networkBio)
if g > 0 and self.encrypted != '':
r = m2bio_write(networkBio, self.encrypted)
if r <= 0:
assert(m2bio_should_retry(networkBio))
else:
self.encrypted = self.encrypted[r:]
pending = m2bio_ctrl_pending(sslBioPtr)
if pending:
d = m2bio_read(sslBioPtr, pending)
if d is not None: # This is strange, but d can be None
decryptedData += d
else:
assert(m2bio_should_retry(sslBioPtr))
else:
break
return decryptedData