Windows transparent proxy: allow specification of custom WinDivert filter rules

This commit is contained in:
Maximilian Hils 2014-08-30 17:33:43 +02:00
parent 101209ef9f
commit 82730c1c6f

View File

@ -96,6 +96,7 @@ class MIB_TCPROW2(Structure):
('dwOffloadState', DWORD) ('dwOffloadState', DWORD)
] ]
# http://msdn.microsoft.com/en-us/library/windows/desktop/bb485772(v=vs.85).aspx # http://msdn.microsoft.com/en-us/library/windows/desktop/bb485772(v=vs.85).aspx
def MIB_TCPTABLE2(size): def MIB_TCPTABLE2(size):
class _MIB_TCPTABLE2(Structure): class _MIB_TCPTABLE2(Structure):
@ -151,7 +152,7 @@ class TransparentProxy(object):
def __init__(self, def __init__(self,
mode="both", mode="both",
redirect_ports=(80, 443), redirect_ports=(80, 443), custom_filter=None,
proxy_addr=False, proxy_port=8080, proxy_addr=False, proxy_port=8080,
api_host="localhost", api_port=PROXY_API_PORT, api_host="localhost", api_port=PROXY_API_PORT,
cache_size=65536): cache_size=65536):
@ -159,6 +160,8 @@ class TransparentProxy(object):
:param mode: Redirection operation mode: "forward" to only redirect forwarded packets, "local" to only redirect :param mode: Redirection operation mode: "forward" to only redirect forwarded packets, "local" to only redirect
packets originating from the local machine, "both" to redirect both. packets originating from the local machine, "both" to redirect both.
:param redirect_ports: if the destination port is in this tuple, the requests are redirected to the proxy. :param redirect_ports: if the destination port is in this tuple, the requests are redirected to the proxy.
:param custom_filter: specify a custom WinDivert filter to select packets that should be intercepted. Overrides
redirect_ports setting.
:param proxy_addr: IP address of the proxy (IP within a network, 127.0.0.1 does not work). By default, :param proxy_addr: IP address of the proxy (IP within a network, 127.0.0.1 does not work). By default,
this is detected automatically. this is detected automatically.
:param proxy_port: Port the proxy is listenting on. :param proxy_port: Port the proxy is listenting on.
@ -167,7 +170,6 @@ class TransparentProxy(object):
:param cache_size: Maximum number of connection tuples that are stored. Only relevant in very high :param cache_size: Maximum number of connection tuples that are stored. Only relevant in very high
load scenarios. load scenarios.
""" """
if proxy_port in redirect_ports: if proxy_port in redirect_ports:
raise ValueError("The proxy port must not be a redirect port.") raise ValueError("The proxy port must not be a redirect port.")
@ -192,7 +194,7 @@ class TransparentProxy(object):
self.driver = WinDivert() self.driver = WinDivert()
self.driver.register() self.driver.register()
self.request_filter = " or ".join(("tcp.DstPort == %d" % p) for p in redirect_ports) self.request_filter = custom_filter or " or ".join(("tcp.DstPort == %d" % p) for p in redirect_ports)
self.request_forward_handle = None self.request_forward_handle = None
self.request_forward_thread = threading.Thread(target=self.request_forward) self.request_forward_thread = threading.Thread(target=self.request_forward)
self.request_forward_thread.daemon = True self.request_forward_thread.daemon = True
@ -236,7 +238,8 @@ class TransparentProxy(object):
self.response_thread.start() self.response_thread.start()
if self.mode == "forward" or self.mode == "both": if self.mode == "forward" or self.mode == "both":
self.request_forward_handle = self.driver.open_handle(filter=self.request_filter, layer=Layer.NETWORK_FORWARD) self.request_forward_handle = self.driver.open_handle(filter=self.request_filter,
layer=Layer.NETWORK_FORWARD)
self.request_forward_thread.start() self.request_forward_thread.start()
if self.mode == "local" or self.mode == "both": if self.mode == "local" or self.mode == "both":
self.request_local_handle = self.driver.open_handle(filter=self.request_filter, layer=Layer.NETWORK) self.request_local_handle = self.driver.open_handle(filter=self.request_filter, layer=Layer.NETWORK)
@ -329,7 +332,7 @@ class TransparentProxy(object):
metadata.direction = Direction.INBOUND metadata.direction = Direction.INBOUND
packet = self.driver.update_packet_checksums(packet) packet = self.driver.update_packet_checksums(packet)
# Use any handle thats on the NETWORK layer - request_local may be unavailable. # Use any handle thats on the NETWORK layer - request_local may be unavailable.
self.response_handle.send((packet.raw, metadata)) self.response_handle.send((packet.raw, metadata))
def response(self): def response(self):
@ -357,24 +360,28 @@ class TransparentProxy(object):
if __name__ == "__main__": if __name__ == "__main__":
parser = argparse.ArgumentParser(description="Windows Transparent Proxy") parser = argparse.ArgumentParser(description="Windows Transparent Proxy")
parser.add_argument('--mode', choices=['forward', 'local', 'both'], default="both", parser.add_argument('--mode', choices=['forward', 'local', 'both'], default="both",
help='Redirection operation mode: "forward" to only redirect forwarded packets, ' help='redirection operation mode: "forward" to only redirect forwarded packets, '
'"local" to only redirect packets originating from the local machine') '"local" to only redirect packets originating from the local machine')
parser.add_argument("--redirect-ports", nargs="+", type=int, default=[80, 443], metavar="80", group = parser.add_mutually_exclusive_group()
help="ports that should be forwarded to the proxy") group.add_argument("--redirect-ports", nargs="+", type=int, default=[80, 443], metavar="80",
help="ports that should be forwarded to the proxy")
group.add_argument("--custom-filter", default=None, metavar="WINDIVERT_FILTER",
help="Custom WinDivert interception rule.")
parser.add_argument("--proxy-addr", default=False, parser.add_argument("--proxy-addr", default=False,
help="proxy server address") help="Proxy Server Address")
parser.add_argument("--proxy-port", type=int, default=8080, parser.add_argument("--proxy-port", type=int, default=8080,
help="proxy server port") help="Proxy Server Port")
parser.add_argument("--api-host", default="localhost", parser.add_argument("--api-host", default="localhost",
help="API hostname to bind to") help="API hostname to bind to")
parser.add_argument("--api-port", type=int, default=PROXY_API_PORT, parser.add_argument("--api-port", type=int, default=PROXY_API_PORT,
help="API port") help="API port")
parser.add_argument("--cache-size", type=int, default=65536, parser.add_argument("--cache-size", type=int, default=65536,
help="maximum connection cache size") help="Maximum connection cache size")
options = parser.parse_args() options = parser.parse_args()
proxy = TransparentProxy(**vars(options)) proxy = TransparentProxy(**vars(options))
proxy.start() proxy.start()
print(" * Transparent proxy active.") print(" * Transparent proxy active.")
print(" Filter: {0}".format(proxy.request_filter))
try: try:
while True: while True:
time.sleep(1) time.sleep(1)