323 lines
12 KiB
Python
323 lines
12 KiB
Python
# Copyright 2019 The Matrix.org Foundation C.I.C.
|
|
#
|
|
# 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.
|
|
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
|
|
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, IPolicyForHTTPS
|
|
|
|
from synapse.http.connectproxyclient import HTTPConnectProxyEndpoint
|
|
|
|
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
|
|
|
|
Args:
|
|
reactor: twisted reactor to place outgoing
|
|
connections.
|
|
|
|
proxy_reactor: twisted reactor to use for connections to the proxy server
|
|
reactor might have some blacklisting applied (i.e. for DNS queries),
|
|
but we need unblocked access to the proxy.
|
|
|
|
contextFactory (IPolicyForHTTPS): A factory for TLS contexts, to control the
|
|
verification parameters of OpenSSL. The default is to use a
|
|
`BrowserLikePolicyForHTTPS`, so unless you have special
|
|
requirements you can leave this as-is.
|
|
|
|
connectTimeout (Optional[float]): The amount of time that this Agent will wait
|
|
for the peer to accept a connection, in seconds. If 'None',
|
|
HostnameEndpoint's default (30s) will be used.
|
|
|
|
This is used for connections to both proxies and destination servers.
|
|
|
|
bindAddress (bytes): The local address for client sockets to bind to.
|
|
|
|
pool (HTTPConnectionPool|None): connection pool to be used. If None, a
|
|
non-persistent pool instance will be created.
|
|
|
|
use_proxy (bool): Whether proxy settings should be discovered and used
|
|
from conventional environment variables.
|
|
"""
|
|
|
|
def __init__(
|
|
self,
|
|
reactor,
|
|
proxy_reactor=None,
|
|
contextFactory: Optional[IPolicyForHTTPS] = None,
|
|
connectTimeout=None,
|
|
bindAddress=None,
|
|
pool=None,
|
|
use_proxy=False,
|
|
):
|
|
contextFactory = contextFactory or BrowserLikePolicyForHTTPS()
|
|
|
|
_AgentBase.__init__(self, reactor, pool)
|
|
|
|
if proxy_reactor is None:
|
|
self.proxy_reactor = reactor
|
|
else:
|
|
self.proxy_reactor = proxy_reactor
|
|
|
|
self._endpoint_kwargs = {}
|
|
if connectTimeout is not None:
|
|
self._endpoint_kwargs["timeout"] = connectTimeout
|
|
if bindAddress is not None:
|
|
self._endpoint_kwargs["bindAddress"] = bindAddress
|
|
|
|
http_proxy = None
|
|
https_proxy = None
|
|
no_proxy = None
|
|
if use_proxy:
|
|
proxies = getproxies_environment()
|
|
http_proxy = proxies["http"].encode() if "http" in proxies else None
|
|
https_proxy = proxies["https"].encode() if "https" in proxies else None
|
|
no_proxy = proxies["no"] if "no" in proxies else None
|
|
|
|
# Parse credentials from http and https proxy connection string if present
|
|
self.http_proxy_creds, http_proxy = parse_username_password(http_proxy)
|
|
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
|
|
)
|
|
|
|
self.https_proxy_endpoint = _http_proxy_endpoint(
|
|
https_proxy, self.proxy_reactor, **self._endpoint_kwargs
|
|
)
|
|
|
|
self.no_proxy = no_proxy
|
|
|
|
self._policy_for_https = contextFactory
|
|
self._reactor = reactor
|
|
|
|
def request(self, method, uri, headers=None, bodyProducer=None):
|
|
"""
|
|
Issue a request to the server indicated by the given uri.
|
|
|
|
Supports `http` and `https` schemes.
|
|
|
|
An existing connection from the connection pool may be used or a new one may be
|
|
created.
|
|
|
|
See also: twisted.web.iweb.IAgent.request
|
|
|
|
Args:
|
|
method (bytes): The request method to use, such as `GET`, `POST`, etc
|
|
|
|
uri (bytes): The location of the resource to request.
|
|
|
|
headers (Headers|None): Extra headers to send with the request
|
|
|
|
bodyProducer (IBodyProducer|None): An object which can generate bytes to
|
|
make up the body of this request (for example, the properly encoded
|
|
contents of a file for a file upload). Or, None if the request is to
|
|
have no body.
|
|
|
|
Returns:
|
|
Deferred[IResponse]: completes when the header of the response has
|
|
been received (regardless of the response status code).
|
|
|
|
Can fail with:
|
|
SchemeNotSupported: if the uri is not http or https
|
|
|
|
twisted.internet.error.TimeoutError if the server we are connecting
|
|
to (proxy or destination) does not accept a connection before
|
|
connectTimeout.
|
|
|
|
... other things too.
|
|
"""
|
|
uri = uri.strip()
|
|
if not _VALID_URI.match(uri):
|
|
raise ValueError(f"Invalid URI {uri!r}")
|
|
|
|
parsed_uri = URI.fromBytes(uri)
|
|
pool_key = (parsed_uri.scheme, parsed_uri.host, parsed_uri.port)
|
|
request_path = parsed_uri.originForm
|
|
|
|
should_skip_proxy = False
|
|
if self.no_proxy is not None:
|
|
should_skip_proxy = proxy_bypass_environment(
|
|
parsed_uri.host.decode(),
|
|
proxies={"no": self.no_proxy},
|
|
)
|
|
|
|
if (
|
|
parsed_uri.scheme == b"http"
|
|
and self.http_proxy_endpoint
|
|
and not should_skip_proxy
|
|
):
|
|
# Determine whether we need to set Proxy-Authorization headers
|
|
if self.http_proxy_creds:
|
|
# Set a Proxy-Authorization header
|
|
if headers is None:
|
|
headers = Headers()
|
|
headers.addRawHeader(
|
|
b"Proxy-Authorization",
|
|
self.http_proxy_creds.as_proxy_authorization_value(),
|
|
)
|
|
# Cache *all* connections under the same key, since we are only
|
|
# connecting to a single destination, the proxy:
|
|
pool_key = ("http-proxy", self.http_proxy_endpoint)
|
|
endpoint = self.http_proxy_endpoint
|
|
request_path = uri
|
|
elif (
|
|
parsed_uri.scheme == b"https"
|
|
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
|
|
endpoint = HostnameEndpoint(
|
|
self._reactor, parsed_uri.host, parsed_uri.port, **self._endpoint_kwargs
|
|
)
|
|
|
|
logger.debug("Requesting %s via %s", uri, endpoint)
|
|
|
|
if parsed_uri.scheme == b"https":
|
|
tls_connection_creator = self._policy_for_https.creatorForNetloc(
|
|
parsed_uri.host, parsed_uri.port
|
|
)
|
|
endpoint = wrapClientTLS(tls_connection_creator, endpoint)
|
|
elif parsed_uri.scheme == b"http":
|
|
pass
|
|
else:
|
|
return defer.fail(
|
|
Failure(
|
|
SchemeNotSupported("Unsupported scheme: %r" % (parsed_uri.scheme,))
|
|
)
|
|
)
|
|
|
|
return self._requestWithEndpoint(
|
|
pool_key, endpoint, method, parsed_uri, headers, bodyProducer, request_path
|
|
)
|
|
|
|
|
|
def _http_proxy_endpoint(proxy: Optional[bytes], reactor, **kwargs):
|
|
"""Parses an http proxy setting and returns an endpoint for the proxy
|
|
|
|
Args:
|
|
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:
|
|
interfaces.IStreamClientEndpoint|None: endpoint to use to connect to the proxy,
|
|
or None
|
|
"""
|
|
if proxy is None:
|
|
return None
|
|
|
|
# Parse the connection string
|
|
host, port = parse_host_port(proxy, default_port=1080)
|
|
return HostnameEndpoint(reactor, host, port, **kwargs)
|
|
|
|
|
|
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:
|
|
port = int(port)
|
|
return host, port
|
|
except ValueError:
|
|
# the thing after the : wasn't a valid port; presumably this is an
|
|
# IPv6 address.
|
|
pass
|
|
|
|
return hostport, default_port
|