154 lines
6.5 KiB
Python
154 lines
6.5 KiB
Python
###############################################################################
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#
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# The MIT License (MIT)
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#
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# Copyright (c) Crossbar.io Technologies GmbH
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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
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# all 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
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# THE SOFTWARE.
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#
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###############################################################################
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import hashlib
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from typing import Optional
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from twisted.internet.defer import Deferred
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from twisted.internet.address import IPv4Address, UNIXAddress
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try:
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from twisted.internet.stdio import PipeAddress
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except ImportError:
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# stdio.PipeAddress is only avail on Twisted 13.0+
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PipeAddress = type(None)
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try:
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from twisted.internet.address import IPv6Address
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_HAS_IPV6 = True
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except ImportError:
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_HAS_IPV6 = False
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__all = (
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'sleep',
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'peer2str',
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'transport_channel_id'
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)
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def sleep(delay, reactor=None):
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"""
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Inline sleep for use in co-routines (Twisted ``inlineCallback`` decorated functions).
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.. seealso::
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* `twisted.internet.defer.inlineCallbacks <http://twistedmatrix.com/documents/current/api/twisted.internet.defer.html#inlineCallbacks>`__
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* `twisted.internet.interfaces.IReactorTime <http://twistedmatrix.com/documents/current/api/twisted.internet.interfaces.IReactorTime.html>`__
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:param delay: Time to sleep in seconds.
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:type delay: float
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:param reactor: The Twisted reactor to use.
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:type reactor: None or provider of ``IReactorTime``.
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"""
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if not reactor:
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from twisted.internet import reactor
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d = Deferred()
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reactor.callLater(delay, d.callback, None)
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return d
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def peer2str(addr):
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"""
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Convert a Twisted address as returned from ``self.transport.getPeer()`` to a string.
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:returns: Returns a string representation of the peer on a Twisted transport.
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:rtype: unicode
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"""
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if isinstance(addr, IPv4Address):
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res = "tcp4:{0}:{1}".format(addr.host, addr.port)
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elif _HAS_IPV6 and isinstance(addr, IPv6Address):
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res = "tcp6:{0}:{1}".format(addr.host, addr.port)
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elif isinstance(addr, UNIXAddress):
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res = "unix:{0}".format(addr.name)
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elif isinstance(addr, PipeAddress):
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res = "<pipe>"
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else:
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# gracefully fallback if we can't map the peer's address
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res = "?:{0}".format(addr)
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return res
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try:
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from twisted.protocols.tls import TLSMemoryBIOProtocol
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except ImportError:
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def transport_channel_id(transport: object, is_server: bool, channel_id_type: Optional[str] = None) -> bytes:
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if channel_id_type is None:
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return b'\x00' * 32
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else:
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def transport_channel_id(transport: TLSMemoryBIOProtocol, is_server: bool, channel_id_type: Optional[str] = None) -> bytes:
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"""
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Application-layer user authentication protocols are vulnerable to generic
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credential forwarding attacks, where an authentication credential sent by
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a client C to a server M may then be used by M to impersonate C at another
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server S. To prevent such credential forwarding attacks, modern authentication
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protocols rely on channel bindings. For example, WAMP-cryptosign can use
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the tls-unique channel identifier provided by the TLS layer to strongly bind
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authentication credentials to the underlying channel, so that a credential
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received on one TLS channel cannot be forwarded on another.
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:param transport: The Twisted TLS transport to extract the TLS channel ID from.
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:param is_server: Flag indicating the transport is for a server.
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:param channel_id_type: TLS channel ID type, currently only "tls-unique" is supported.
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:returns: The TLS channel id (32 bytes).
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"""
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if channel_id_type is None:
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return b'\x00' * 32
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if channel_id_type not in ['tls-unique']:
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raise Exception("invalid channel ID type {}".format(channel_id_type))
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# transport: instance of :class:`twisted.protocols.tls.TLSMemoryBIOProtocol`
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# transport._tlsConnection: instance of :class:`OpenSSL.SSL.Connection`
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if not hasattr(transport, '_tlsConnection'):
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print("TLS transport channel_id for tls-unique requested, but _tlsConnection not found on transport {}".format(dir(transport)))
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return b'\x00' * 32
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# Obtain latest TLS Finished message that we expected from peer, or None if handshake is not completed.
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# http://www.pyopenssl.org/en/stable/api/ssl.html#OpenSSL.SSL.Connection.get_peer_finished
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is_not_resumed = True
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if channel_id_type == 'tls-unique':
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# see also: https://bugs.python.org/file22646/tls_channel_binding.patch
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if is_server != is_not_resumed:
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# for routers (=servers) XOR new sessions, the channel ID is based on the TLS Finished message we
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# expected to receive from the client
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tls_finished_msg = transport._tlsConnection.get_peer_finished()
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else:
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# for clients XOR resumed sessions, the channel ID is based on the TLS Finished message we sent
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# to the router (=server)
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tls_finished_msg = transport._tlsConnection.get_finished()
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if tls_finished_msg is None:
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# this can occur if we made a successful connection (in a
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# TCP sense) but something failed with the TLS handshake
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# (e.g. invalid certificate)
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return b'\x00' * 32
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else:
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m = hashlib.sha256()
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m.update(tls_finished_msg)
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return m.digest()
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else:
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assert False, 'should not arrive here'
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