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Allow providing credentials to HTTPS_PROXY (#9657) 

Addresses https://github.com/matrix-org/synapse-dinsic/issues/70

This PR causes `ProxyAgent` to attempt to extract credentials from an `HTTPS_PROXY` env var. If credentials are found, a `Proxy-Authorization` header ([details](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Proxy-Authorization)) is sent to the proxy server to authenticate against it. The headers are *not* passed to the remote server.

Also added some type hints.
This commit is contained in:
Andrew Morgan 2021-03-22 17:20:47 +00:00 committed by GitHub
parent 4612302399
commit 5b268997bd
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4 changed files with 184 additions and 34 deletions
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1
changelog.d/9657.feature Normal file
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@ -0,0 +1 @@
Add support for credentials for proxy authentication in the `HTTPS_PROXY` environment variable.

96
synapse/http/connectproxyclient.py
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@ -19,9 +19,10 @@ from zope.interface import implementer
from twisted.internet import defer, protocol
from twisted.internet.error import ConnectError
from twisted.internet.interfaces import IStreamClientEndpoint
from twisted.internet.protocol import connectionDone
from twisted.internet.interfaces import IReactorCore, IStreamClientEndpoint
from twisted.internet.protocol import ClientFactory, Protocol, connectionDone
from twisted.web import http
from twisted.web.http_headers import Headers
logger = logging.getLogger(__name__)
@ -43,23 +44,33 @@ class HTTPConnectProxyEndpoint:
Args:
reactor: the Twisted reactor to use for the connection
proxy_endpoint (IStreamClientEndpoint): the endpoint to use to connect to the
proxy
host (bytes): hostname that we want to CONNECT to
port (int): port that we want to connect to
proxy_endpoint: the endpoint to use to connect to the proxy
host: hostname that we want to CONNECT to
port: port that we want to connect to
headers: Extra HTTP headers to include in the CONNECT request
"""
def __init__(self, reactor, proxy_endpoint, host, port):
def __init__(
self,
reactor: IReactorCore,
proxy_endpoint: IStreamClientEndpoint,
host: bytes,
port: int,
headers: Headers,
):
self._reactor = reactor
self._proxy_endpoint = proxy_endpoint
self._host = host
self._port = port
self._headers = headers
def __repr__(self):
return "<HTTPConnectProxyEndpoint %s>" % (self._proxy_endpoint,)
def connect(self, protocolFactory):
f = HTTPProxiedClientFactory(self._host, self._port, protocolFactory)
def connect(self, protocolFactory: ClientFactory):
f = HTTPProxiedClientFactory(
self._host, self._port, protocolFactory, self._headers
)
d = self._proxy_endpoint.connect(f)
# once the tcp socket connects successfully, we need to wait for the
# CONNECT to complete.
@ -74,15 +85,23 @@ class HTTPProxiedClientFactory(protocol.ClientFactory):
HTTP Protocol object and run the rest of the connection.
Args:
dst_host (bytes): hostname that we want to CONNECT to
dst_port (int): port that we want to connect to
wrapped_factory (protocol.ClientFactory): The original Factory
dst_host: hostname that we want to CONNECT to
dst_port: port that we want to connect to
wrapped_factory: The original Factory
headers: Extra HTTP headers to include in the CONNECT request
"""
def __init__(self, dst_host, dst_port, wrapped_factory):
def __init__(
self,
dst_host: bytes,
dst_port: int,
wrapped_factory: ClientFactory,
headers: Headers,
):
self.dst_host = dst_host
self.dst_port = dst_port
self.wrapped_factory = wrapped_factory
self.headers = headers
self.on_connection = defer.Deferred()
def startedConnecting(self, connector):
@ -92,7 +111,11 @@ class HTTPProxiedClientFactory(protocol.ClientFactory):
wrapped_protocol = self.wrapped_factory.buildProtocol(addr)
return HTTPConnectProtocol(
self.dst_host, self.dst_port, wrapped_protocol, self.on_connection
self.dst_host,
self.dst_port,
wrapped_protocol,
self.on_connection,
self.headers,
)
def clientConnectionFailed(self, connector, reason):
@ -112,24 +135,37 @@ class HTTPConnectProtocol(protocol.Protocol):
"""Protocol that wraps an existing Protocol to do a CONNECT handshake at connect
Args:
host (bytes): The original HTTP(s) hostname or IPv4 or IPv6 address literal
host: The original HTTP(s) hostname or IPv4 or IPv6 address literal
to put in the CONNECT request
port (int): The original HTTP(s) port to put in the CONNECT request
port: The original HTTP(s) port to put in the CONNECT request
wrapped_protocol (interfaces.IProtocol): the original protocol (probably
HTTPChannel or TLSMemoryBIOProtocol, but could be anything really)
wrapped_protocol: the original protocol (probably HTTPChannel or
TLSMemoryBIOProtocol, but could be anything really)
connected_deferred (Deferred): a Deferred which will be callbacked with
connected_deferred: a Deferred which will be callbacked with
wrapped_protocol when the CONNECT completes
headers: Extra HTTP headers to include in the CONNECT request
"""
def __init__(self, host, port, wrapped_protocol, connected_deferred):
def __init__(
self,
host: bytes,
port: int,
wrapped_protocol: Protocol,
connected_deferred: defer.Deferred,
headers: Headers,
):
self.host = host
self.port = port
self.wrapped_protocol = wrapped_protocol
self.connected_deferred = connected_deferred
self.http_setup_client = HTTPConnectSetupClient(self.host, self.port)
self.headers = headers
self.http_setup_client = HTTPConnectSetupClient(
self.host, self.port, self.headers
)
self.http_setup_client.on_connected.addCallback(self.proxyConnected)
def connectionMade(self):
@ -154,7 +190,7 @@ class HTTPConnectProtocol(protocol.Protocol):
if buf:
self.wrapped_protocol.dataReceived(buf)
def dataReceived(self, data):
def dataReceived(self, data: bytes):
# if we've set up the HTTP protocol, we can send the data there
if self.wrapped_protocol.connected:
return self.wrapped_protocol.dataReceived(data)
@ -168,21 +204,29 @@ class HTTPConnectSetupClient(http.HTTPClient):
"""HTTPClient protocol to send a CONNECT message for proxies and read the response.
Args:
host (bytes): The hostname to send in the CONNECT message
port (int): The port to send in the CONNECT message
host: The hostname to send in the CONNECT message
port: The port to send in the CONNECT message
headers: Extra headers to send with the CONNECT message
"""
def __init__(self, host, port):
def __init__(self, host: bytes, port: int, headers: Headers):
self.host = host
self.port = port
self.headers = headers
self.on_connected = defer.Deferred()
def connectionMade(self):
logger.debug("Connected to proxy, sending CONNECT")
self.sendCommand(b"CONNECT", b"%s:%d" % (self.host, self.port))
# Send any additional specified headers
for name, values in self.headers.getAllRawHeaders():
for value in values:
self.sendHeader(name, value)
self.endHeaders()
def handleStatus(self, version, status, message):
def handleStatus(self, version: bytes, status: bytes, message: bytes):
logger.debug("Got Status: %s %s %s", status, message, version)
if status != b"200":
raise ProxyConnectError("Unexpected status on CONNECT: %s" % status)

81
synapse/http/proxyagent.py
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@ -12,10 +12,13 @@
# 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.
import base64
import logging
import re
from typing import Optional, Tuple
from urllib.request import getproxies_environment, proxy_bypass_environment
import attr
from zope.interface import implementer
from twisted.internet import defer
@ -23,6 +26,7 @@ from twisted.internet.endpoints import HostnameEndpoint, wrapClientTLS
from twisted.python.failure import Failure
from twisted.web.client import URI, BrowserLikePolicyForHTTPS, _AgentBase
from twisted.web.error import SchemeNotSupported
from twisted.web.http_headers import Headers
from twisted.web.iweb import IAgent
from synapse.http.connectproxyclient import HTTPConnectProxyEndpoint
@ -32,6 +36,22 @@ logger = logging.getLogger(__name__)
_VALID_URI = re.compile(br"\A[\x21-\x7e]+\Z")
@attr.s
class ProxyCredentials:
username_password = attr.ib(type=bytes)
def as_proxy_authorization_value(self) -> bytes:
"""
Return the value for a Proxy-Authorization header (i.e. 'Basic abdef==').
Returns:
A transformation of the authentication string the encoded value for
a Proxy-Authorization header.
"""
# Encode as base64 and prepend the authorization type
return b"Basic " + base64.encodebytes(self.username_password)
@implementer(IAgent)
class ProxyAgent(_AgentBase):
"""An Agent implementation which will use an HTTP proxy if one was requested
@ -96,6 +116,9 @@ class ProxyAgent(_AgentBase):
https_proxy = proxies["https"].encode() if "https" in proxies else None
no_proxy = proxies["no"] if "no" in proxies else None
# Parse credentials from https proxy connection string if present
self.https_proxy_creds, https_proxy = parse_username_password(https_proxy)
self.http_proxy_endpoint = _http_proxy_endpoint(
http_proxy, self.proxy_reactor, **self._endpoint_kwargs
)
@ -175,11 +198,22 @@ class ProxyAgent(_AgentBase):
and self.https_proxy_endpoint
and not should_skip_proxy
):
connect_headers = Headers()
# Determine whether we need to set Proxy-Authorization headers
if self.https_proxy_creds:
# Set a Proxy-Authorization header
connect_headers.addRawHeader(
b"Proxy-Authorization",
self.https_proxy_creds.as_proxy_authorization_value(),
)
endpoint = HTTPConnectProxyEndpoint(
self.proxy_reactor,
self.https_proxy_endpoint,
parsed_uri.host,
parsed_uri.port,
headers=connect_headers,
)
else:
# not using a proxy
@ -208,12 +242,16 @@ class ProxyAgent(_AgentBase):
)
def _http_proxy_endpoint(proxy, reactor, **kwargs):
def _http_proxy_endpoint(proxy: Optional[bytes], reactor, **kwargs):
"""Parses an http proxy setting and returns an endpoint for the proxy
Args:
proxy (bytes|None): the proxy setting
proxy: the proxy setting in the form: [<username>:<password>@]<host>[:<port>]
Note that compared to other apps, this function currently lacks support
for specifying a protocol schema (i.e. protocol://...).
reactor: reactor to be used to connect to the proxy
kwargs: other args to be passed to HostnameEndpoint
Returns:
@ -223,16 +261,43 @@ def _http_proxy_endpoint(proxy, reactor, **kwargs):
if proxy is None:
return None
# currently we only support hostname:port. Some apps also support
# protocol://<host>[:port], which allows a way of requiring a TLS connection to the
# proxy.
# Parse the connection string
host, port = parse_host_port(proxy, default_port=1080)
return HostnameEndpoint(reactor, host, port, **kwargs)
def parse_host_port(hostport, default_port=None):
# could have sworn we had one of these somewhere else...
def parse_username_password(proxy: bytes) -> Tuple[Optional[ProxyCredentials], bytes]:
"""
Parses the username and password from a proxy declaration e.g
username:password@hostname:port.
Args:
proxy: The proxy connection string.
Returns
An instance of ProxyCredentials and the proxy connection string with any credentials
stripped, i.e u:p@host:port -> host:port. If no credentials were found, the
ProxyCredentials instance is replaced with None.
"""
if proxy and b"@" in proxy:
# We use rsplit here as the password could contain an @ character
credentials, proxy_without_credentials = proxy.rsplit(b"@", 1)
return ProxyCredentials(credentials), proxy_without_credentials
return None, proxy
def parse_host_port(hostport: bytes, default_port: int = None) -> Tuple[bytes, int]:
"""
Parse the hostname and port from a proxy connection byte string.
Args:
hostport: The proxy connection string. Must be in the form 'host[:port]'.
default_port: The default port to return if one is not found in `hostport`.
Returns:
A tuple containing the hostname and port. Uses `default_port` if one was not found.
"""
if b":" in hostport:
host, port = hostport.rsplit(b":", 1)
try:

40
tests/http/test_proxyagent.py
View File

@ -12,8 +12,10 @@
# 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.
import base64
import logging
import os
from typing import Optional
from unittest.mock import patch
import treq
@ -242,6 +244,21 @@ class MatrixFederationAgentTests(TestCase):
@patch.dict(os.environ, {"https_proxy": "proxy.com", "no_proxy": "unused.com"})
def test_https_request_via_proxy(self):
"""Tests that TLS-encrypted requests can be made through a proxy"""
self._do_https_request_via_proxy(auth_credentials=None)
@patch.dict(
os.environ,
{"https_proxy": "bob:pinkponies@proxy.com", "no_proxy": "unused.com"},
)
def test_https_request_via_proxy_with_auth(self):
"""Tests that authenticated, TLS-encrypted requests can be made through a proxy"""
self._do_https_request_via_proxy(auth_credentials="bob:pinkponies")
def _do_https_request_via_proxy(
self,
auth_credentials: Optional[str] = None,
):
agent = ProxyAgent(
self.reactor,
contextFactory=get_test_https_policy(),
@ -278,6 +295,22 @@ class MatrixFederationAgentTests(TestCase):
self.assertEqual(request.method, b"CONNECT")
self.assertEqual(request.path, b"test.com:443")
# Check whether auth credentials have been supplied to the proxy
proxy_auth_header_values = request.requestHeaders.getRawHeaders(
b"Proxy-Authorization"
)
if auth_credentials is not None:
# Compute the correct header value for Proxy-Authorization
encoded_credentials = base64.b64encode(b"bob:pinkponies")
expected_header_value = b"Basic " + encoded_credentials
# Validate the header's value
self.assertIn(expected_header_value, proxy_auth_header_values)
else:
# Check that the Proxy-Authorization header has not been supplied to the proxy
self.assertIsNone(proxy_auth_header_values)
# tell the proxy server not to close the connection
proxy_server.persistent = True
@ -312,6 +345,13 @@ class MatrixFederationAgentTests(TestCase):
self.assertEqual(request.method, b"GET")
self.assertEqual(request.path, b"/abc")
self.assertEqual(request.requestHeaders.getRawHeaders(b"host"), [b"test.com"])
# Check that the destination server DID NOT receive proxy credentials
proxy_auth_header_values = request.requestHeaders.getRawHeaders(
b"Proxy-Authorization"
)
self.assertIsNone(proxy_auth_header_values)
request.write(b"result")
request.finish()