128 lines
4.8 KiB
Python
128 lines
4.8 KiB
Python
###############################################################################
|
|
#
|
|
# The MIT License (MIT)
|
|
#
|
|
# Copyright (c) Tavendo GmbH
|
|
#
|
|
# Permission is hereby granted, free of charge, to any person obtaining a copy
|
|
# of this software and associated documentation files (the "Software"), to deal
|
|
# in the Software without restriction, including without limitation the rights
|
|
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
|
|
# copies of the Software, and to permit persons to whom the Software is
|
|
# furnished to do so, subject to the following conditions:
|
|
#
|
|
# The above copyright notice and this permission notice shall be included in
|
|
# all copies or substantial portions of the Software.
|
|
#
|
|
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
|
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
|
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
|
|
# THE SOFTWARE.
|
|
#
|
|
###############################################################################
|
|
|
|
import re
|
|
|
|
from twisted.internet.protocol import Protocol, Factory
|
|
|
|
__all__ = (
|
|
'FlashPolicyProtocol',
|
|
'FlashPolicyFactory'
|
|
)
|
|
|
|
|
|
class FlashPolicyProtocol(Protocol):
|
|
"""
|
|
Flash Player 9 (version 9.0.124.0 and above) implements a strict new access
|
|
policy for Flash applications that make Socket or XMLSocket connections to
|
|
a remote host. It now requires the presence of a socket policy file
|
|
on the server.
|
|
|
|
We want this to support the Flash WebSockets bridge which is needed for
|
|
older browser, in particular MSIE9/8.
|
|
|
|
.. seealso::
|
|
* `Autobahn WebSocket fallbacks example <https://github.com/tavendo/AutobahnPython/tree/master/examples/twisted/websocket/echo_wsfallbacks>`_
|
|
* `Flash policy files background <http://www.lightsphere.com/dev/articles/flash_socket_policy.html>`_
|
|
"""
|
|
|
|
REQUESTPAT = re.compile("^\s*<policy-file-request\s*/>")
|
|
REQUESTMAXLEN = 200
|
|
REQUESTTIMEOUT = 5
|
|
POLICYFILE = """<?xml version="1.0"?><cross-domain-policy><allow-access-from domain="%s" to-ports="%s" /></cross-domain-policy>"""
|
|
|
|
def __init__(self, allowedDomain, allowedPorts):
|
|
"""
|
|
|
|
:param allowedPort: The port to which Flash player should be allowed to connect.
|
|
:type allowedPort: int
|
|
"""
|
|
self._allowedDomain = allowedDomain
|
|
self._allowedPorts = allowedPorts
|
|
self.received = ""
|
|
self.dropConnection = None
|
|
|
|
def connectionMade(self):
|
|
# DoS protection
|
|
##
|
|
def dropConnection():
|
|
self.transport.abortConnection()
|
|
self.dropConnection = None
|
|
self.dropConnection = self.factory.reactor.callLater(FlashPolicyProtocol.REQUESTTIMEOUT, dropConnection)
|
|
|
|
def connectionLost(self, reason):
|
|
if self.dropConnection:
|
|
self.dropConnection.cancel()
|
|
self.dropConnection = None
|
|
|
|
def dataReceived(self, data):
|
|
self.received += data
|
|
if FlashPolicyProtocol.REQUESTPAT.match(self.received):
|
|
# got valid request: send policy file
|
|
##
|
|
self.transport.write(FlashPolicyProtocol.POLICYFILE % (self._allowedDomain, self._allowedPorts))
|
|
self.transport.loseConnection()
|
|
elif len(self.received) > FlashPolicyProtocol.REQUESTMAXLEN:
|
|
# possible DoS attack
|
|
##
|
|
self.transport.abortConnection()
|
|
else:
|
|
# need more data
|
|
##
|
|
pass
|
|
|
|
|
|
class FlashPolicyFactory(Factory):
|
|
|
|
def __init__(self, allowedDomain=None, allowedPorts=None, reactor=None):
|
|
"""
|
|
|
|
:param allowedDomain: The domain from which to allow Flash to connect from.
|
|
If ``None``, allow from anywhere.
|
|
:type allowedDomain: str or None
|
|
:param allowedPorts: The ports to which Flash player should be allowed to connect.
|
|
If ``None``, allow any ports.
|
|
:type allowedPorts: list of int or None
|
|
:param reactor: Twisted reactor to use. If not given, autoimport.
|
|
:type reactor: obj
|
|
"""
|
|
# lazy import to avoid reactor install upon module import
|
|
if reactor is None:
|
|
from twisted.internet import reactor
|
|
self.reactor = reactor
|
|
|
|
self._allowedDomain = str(allowedDomain) or "*"
|
|
|
|
if allowedPorts:
|
|
self._allowedPorts = ",".join([str(port) for port in allowedPorts])
|
|
else:
|
|
self._allowedPorts = "*"
|
|
|
|
def buildProtocol(self, addr):
|
|
proto = FlashPolicyProtocol(self._allowedDomain, self._allowedPorts)
|
|
proto.factory = self
|
|
return proto
|