199 lines
6.9 KiB
Python
199 lines
6.9 KiB
Python
# -*- coding: utf-8 -*- #
|
|
# Copyright 2023 Google LLC. All Rights Reserved.
|
|
#
|
|
# Licensed under the Apache License, Version 2.0 (the "License");
|
|
# you may not use this file except in compliance with the License.
|
|
# You may obtain a copy of the License at
|
|
#
|
|
# http://www.apache.org/licenses/LICENSE-2.0
|
|
#
|
|
# Unless required by applicable law or agreed to in writing, software
|
|
# distributed under the License is distributed on an "AS IS" BASIS,
|
|
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
# See the License for the specific language governing permissions and
|
|
# limitations under the License.
|
|
"""Implementation for tunneling through Security Gateway."""
|
|
|
|
from __future__ import absolute_import
|
|
from __future__ import division
|
|
from __future__ import unicode_literals
|
|
|
|
import http.client
|
|
import logging
|
|
import select
|
|
import socket
|
|
import ssl
|
|
import threading
|
|
|
|
from googlecloudsdk.api_lib.compute import iap_tunnel_websocket_utils as iap_utils
|
|
from googlecloudsdk.api_lib.compute import sg_tunnel_utils as sg_utils
|
|
from googlecloudsdk.core import exceptions
|
|
from googlecloudsdk.core import log
|
|
from googlecloudsdk.core import transport
|
|
|
|
|
|
MAX_BYTES_SOCKET_READ = 32768
|
|
RECV_TIMEOUT_SECONDS = 5
|
|
SEND_TIMEOUT_SECONDS = 5
|
|
|
|
RESOURCE_KEY_HEADER = 'X-Resource-Key'
|
|
PROXY_AUTH_HEADER = 'Proxy-Authorization'
|
|
USER_AGENT_HEADER = 'User-Agent'
|
|
|
|
|
|
class SGConnectionError(exceptions.Error):
|
|
pass
|
|
|
|
|
|
class SecurityGatewayTunnel(object):
|
|
"""Creates the tunnel connection to the destination."""
|
|
|
|
def __init__(
|
|
self,
|
|
target,
|
|
access_token_callback,
|
|
send_local_data_callback,
|
|
close_local_connection_callback,
|
|
ignore_certs=False,
|
|
):
|
|
self._ignore_certs = ignore_certs
|
|
|
|
self._get_access_token_callback = access_token_callback
|
|
self._send_local_data_callback = send_local_data_callback
|
|
self._close_local_connection_callback = close_local_connection_callback
|
|
|
|
self._target = target
|
|
|
|
self._sock = None
|
|
self._sending_thread = None
|
|
self._stopping = False
|
|
|
|
# Used to unblock the sending thread immediately instead of waiting for a
|
|
# timeout.
|
|
self._spair, self._rpair = socket.socketpair()
|
|
|
|
def __del__(self):
|
|
self.Close()
|
|
|
|
def InitiateConnection(self):
|
|
"""Starts a tunnel to the destination through Security Gateway."""
|
|
|
|
sg_utils.ValidateParameters(self._target)
|
|
ca_certs = iap_utils.CheckCACertsFile(self._ignore_certs)
|
|
if self._ignore_certs:
|
|
ssl_ctx = ssl._create_unverified_context(cafile=ca_certs) # pylint: disable=protected-access
|
|
else:
|
|
ssl_ctx = ssl.create_default_context(cafile=ca_certs)
|
|
|
|
proxy_host, proxy_port = sg_utils.GetProxyHostPort(
|
|
self._target.url_override)
|
|
|
|
conn = http.client.HTTPSConnection(proxy_host, proxy_port, context=ssl_ctx)
|
|
dst_addr = '{}:{}'.format(self._target.host, self._target.port)
|
|
headers = {}
|
|
if callable(self._get_access_token_callback):
|
|
headers[PROXY_AUTH_HEADER] = 'Bearer {}'.format(
|
|
self._get_access_token_callback())
|
|
if self._target.use_dest_group:
|
|
headers[RESOURCE_KEY_HEADER] = sg_utils.GenerateDestGroupResourcePath(
|
|
self._target.project,
|
|
self._target.region,
|
|
self._target.security_gateway)
|
|
else:
|
|
headers[RESOURCE_KEY_HEADER] = (
|
|
sg_utils.GenerateSecurityGatewayResourcePath(
|
|
self._target.project,
|
|
self._target.region,
|
|
self._target.security_gateway))
|
|
headers[USER_AGENT_HEADER] = transport.MakeUserAgentString()
|
|
log.debug('Sending headers: %s', headers)
|
|
|
|
conn.request('CONNECT', dst_addr, headers=headers)
|
|
resp = http.client.HTTPResponse(conn.sock, method='CONNECT', url=dst_addr)
|
|
(_, code, reason) = resp._read_status() # pylint: disable=protected-access
|
|
if code != http.client.OK:
|
|
log.error('Connection request status [%s] with reason: %s', code, reason)
|
|
raise SGConnectionError(
|
|
'Security Gateway failed to connect to destination url: ' + dst_addr)
|
|
# This is the raw connection to the backend (no SSL wrapping).
|
|
self._sock = conn.sock
|
|
self._sock.setblocking(False)
|
|
log.info('Connected to [%s]', dst_addr)
|
|
|
|
self._sending_thread = threading.Thread(target=self._RunReceive)
|
|
self._sending_thread.daemon = True
|
|
self._sending_thread.start()
|
|
|
|
def ShouldStop(self):
|
|
"""Signals to parent thread that this connection should be closed."""
|
|
|
|
return self._stopping
|
|
|
|
def Close(self):
|
|
"""Attempts to close both the local and tunnel connections."""
|
|
if not self._stopping and self._sending_thread:
|
|
# Attempt to close the sending thread first before continuing to prevent
|
|
# any data races while closing the sockets.
|
|
self._spair.send(b'0')
|
|
self._sending_thread.join()
|
|
|
|
self._close_local_connection_callback()
|
|
|
|
if self._sock is None:
|
|
return
|
|
try:
|
|
# It's recommended to explicitly call shutdown before calling close().
|
|
# See https://docs.python.org/3/howto/sockets.html#disconnecting .
|
|
self._sock.shutdown(socket.SHUT_RDWR)
|
|
self._sock.close()
|
|
except (socket.error, EnvironmentError) as e:
|
|
log.debug('Failed to close connection to remote endpoint: [%s]', e)
|
|
|
|
def Send(self, data):
|
|
"""Attempts to send all bytes in data to the remote endpoint."""
|
|
data_len = len(data)
|
|
if log.GetVerbosity() == logging.DEBUG:
|
|
log.err.GetConsoleWriterStream().write(
|
|
'DEBUG: SEND data_len [%d] data[:20] %r\n' % (data_len, data[:20]))
|
|
sent_data = 0
|
|
while sent_data < data_len:
|
|
try:
|
|
sent_data += self._sock.send(data)
|
|
except (ssl.SSLWantWriteError, ssl.SSLWantReadError, BlockingIOError):
|
|
select.select((), [self._sock], (), SEND_TIMEOUT_SECONDS)
|
|
|
|
def _RunReceive(self):
|
|
"""Receives server data and sends to the local connection."""
|
|
try:
|
|
while not self._stopping:
|
|
if not self._sock:
|
|
break
|
|
ready = [[self._sock]]
|
|
if not self._sock.pending():
|
|
ready = select.select([self._sock, self._rpair], (), (),
|
|
RECV_TIMEOUT_SECONDS)
|
|
for s in ready[0]:
|
|
if s is self._rpair:
|
|
# Another thread is calling Close(), so this thread should stop.
|
|
self._stopping = True
|
|
break
|
|
if s is self._sock:
|
|
data, data_len = self._Read()
|
|
if log.GetVerbosity() == logging.DEBUG:
|
|
log.err.GetConsoleWriterStream().write(
|
|
'DEBUG: RECV data_len [%d] data[:20] %r\n' % (
|
|
data_len, data[:20]))
|
|
if data_len >= 0:
|
|
self._send_local_data_callback(data)
|
|
finally:
|
|
self._stopping = True
|
|
|
|
def _Read(self):
|
|
"""Reads MAX_BYTES_SOCKET_READ bytes of data from the remote endpoint."""
|
|
data = b''
|
|
try:
|
|
data = self._sock.recv(MAX_BYTES_SOCKET_READ)
|
|
except (ssl.SSLWantWriteError, ssl.SSLWantReadError, BlockingIOError):
|
|
return data, -1
|
|
return data, len(data)
|