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synapse/synapse/http/client.py
Patrick Cloke 30fba62108
Apply an IP range blacklist to push and key revocation requests. (#8821) 
Replaces the `federation_ip_range_blacklist` configuration setting with an
`ip_range_blacklist` setting with wider scope. It now applies to:

* Federation
* Identity servers
* Push notifications
* Checking key validitity for third-party invite events

The old `federation_ip_range_blacklist` setting is still honored if present, but
with reduced scope (it only applies to federation and identity servers).
2020-12-02 11:09:24 -05:00

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Python
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# -*- coding: utf-8 -*-
# Copyright 2014-2016 OpenMarket Ltd
# Copyright 2018 New Vector Ltd
#
# 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 logging
import urllib.parse
from io import BytesIO
from typing import (
TYPE_CHECKING,
Any,
BinaryIO,
Dict,
Iterable,
List,
Mapping,
Optional,
Sequence,
Tuple,
Union,
)
import treq
from canonicaljson import encode_canonical_json
from netaddr import IPAddress, IPSet
from prometheus_client import Counter
from zope.interface import implementer, provider
from OpenSSL import SSL
from OpenSSL.SSL import VERIFY_NONE
from twisted.internet import defer, error as twisted_error, protocol, ssl
from twisted.internet.interfaces import (
IAddress,
IHostResolution,
IReactorPluggableNameResolver,
IResolutionReceiver,
)
from twisted.internet.task import Cooperator
from twisted.python.failure import Failure
from twisted.web._newclient import ResponseDone
from twisted.web.client import (
Agent,
HTTPConnectionPool,
ResponseNeverReceived,
readBody,
)
from twisted.web.http import PotentialDataLoss
from twisted.web.http_headers import Headers
from twisted.web.iweb import IAgent, IBodyProducer, IResponse
from synapse.api.errors import Codes, HttpResponseException, SynapseError
from synapse.http import QuieterFileBodyProducer, RequestTimedOutError, redact_uri
from synapse.http.proxyagent import ProxyAgent
from synapse.logging.context import make_deferred_yieldable
from synapse.logging.opentracing import set_tag, start_active_span, tags
from synapse.util import json_decoder
from synapse.util.async_helpers import timeout_deferred
if TYPE_CHECKING:
from synapse.app.homeserver import HomeServer
logger = logging.getLogger(__name__)
outgoing_requests_counter = Counter("synapse_http_client_requests", "", ["method"])
incoming_responses_counter = Counter(
"synapse_http_client_responses", "", ["method", "code"]
)
# the type of the headers list, to be passed to the t.w.h.Headers.
# Actually we can mix str and bytes keys, but Mapping treats 'key' as invariant so
# we simplify.
RawHeaders = Union[Mapping[str, "RawHeaderValue"], Mapping[bytes, "RawHeaderValue"]]
# the value actually has to be a List, but List is invariant so we can't specify that
# the entries can either be Lists or bytes.
RawHeaderValue = Sequence[Union[str, bytes]]
# the type of the query params, to be passed into `urlencode`
QueryParamValue = Union[str, bytes, Iterable[Union[str, bytes]]]
QueryParams = Union[Mapping[str, QueryParamValue], Mapping[bytes, QueryParamValue]]
def check_against_blacklist(
ip_address: IPAddress, ip_whitelist: Optional[IPSet], ip_blacklist: IPSet
) -> bool:
"""
Compares an IP address to allowed and disallowed IP sets.
Args:
ip_address: The IP address to check
ip_whitelist: Allowed IP addresses.
ip_blacklist: Disallowed IP addresses.
Returns:
True if the IP address is in the blacklist and not in the whitelist.
"""
if ip_address in ip_blacklist:
if ip_whitelist is None or ip_address not in ip_whitelist:
return True
return False
_EPSILON = 0.00000001
def _make_scheduler(reactor):
"""Makes a schedular suitable for a Cooperator using the given reactor.
(This is effectively just a copy from `twisted.internet.task`)
"""
def _scheduler(x):
return reactor.callLater(_EPSILON, x)
return _scheduler
class _IPBlacklistingResolver:
"""
A proxy for reactor.nameResolver which only produces non-blacklisted IP
addresses, preventing DNS rebinding attacks on URL preview.
"""
def __init__(
self,
reactor: IReactorPluggableNameResolver,
ip_whitelist: Optional[IPSet],
ip_blacklist: IPSet,
):
"""
Args:
reactor: The twisted reactor.
ip_whitelist: IP addresses to allow.
ip_blacklist: IP addresses to disallow.
"""
self._reactor = reactor
self._ip_whitelist = ip_whitelist
self._ip_blacklist = ip_blacklist
def resolveHostName(
self, recv: IResolutionReceiver, hostname: str, portNumber: int = 0
) -> IResolutionReceiver:
r = recv()
addresses = [] # type: List[IAddress]
def _callback() -> None:
r.resolutionBegan(None)
has_bad_ip = False
for i in addresses:
ip_address = IPAddress(i.host)
if check_against_blacklist(
ip_address, self._ip_whitelist, self._ip_blacklist
):
logger.info(
"Dropped %s from DNS resolution to %s due to blacklist"
% (ip_address, hostname)
)
has_bad_ip = True
# if we have a blacklisted IP, we'd like to raise an error to block the
# request, but all we can really do from here is claim that there were no
# valid results.
if not has_bad_ip:
for i in addresses:
r.addressResolved(i)
r.resolutionComplete()
@provider(IResolutionReceiver)
class EndpointReceiver:
@staticmethod
def resolutionBegan(resolutionInProgress: IHostResolution) -> None:
pass
@staticmethod
def addressResolved(address: IAddress) -> None:
addresses.append(address)
@staticmethod
def resolutionComplete() -> None:
_callback()
self._reactor.nameResolver.resolveHostName(
EndpointReceiver, hostname, portNumber=portNumber
)
return r
@implementer(IReactorPluggableNameResolver)
class BlacklistingReactorWrapper:
"""
A Reactor wrapper which will prevent DNS resolution to blacklisted IP
addresses, to prevent DNS rebinding.
"""
def __init__(
self,
reactor: IReactorPluggableNameResolver,
ip_whitelist: Optional[IPSet],
ip_blacklist: IPSet,
):
self._reactor = reactor
# We need to use a DNS resolver which filters out blacklisted IP
# addresses, to prevent DNS rebinding.
self._nameResolver = _IPBlacklistingResolver(
self._reactor, ip_whitelist, ip_blacklist
)
def __getattr__(self, attr: str) -> Any:
# Passthrough to the real reactor except for the DNS resolver.
if attr == "nameResolver":
return self._nameResolver
else:
return getattr(self._reactor, attr)
class BlacklistingAgentWrapper(Agent):
"""
An Agent wrapper which will prevent access to IP addresses being accessed
directly (without an IP address lookup).
"""
def __init__(
self,
agent: IAgent,
ip_whitelist: Optional[IPSet] = None,
ip_blacklist: Optional[IPSet] = None,
):
"""
Args:
agent: The Agent to wrap.
ip_whitelist: IP addresses to allow.
ip_blacklist: IP addresses to disallow.
"""
self._agent = agent
self._ip_whitelist = ip_whitelist
self._ip_blacklist = ip_blacklist
def request(
self,
method: bytes,
uri: bytes,
headers: Optional[Headers] = None,
bodyProducer: Optional[IBodyProducer] = None,
) -> defer.Deferred:
h = urllib.parse.urlparse(uri.decode("ascii"))
try:
ip_address = IPAddress(h.hostname)
if check_against_blacklist(
ip_address, self._ip_whitelist, self._ip_blacklist
):
logger.info("Blocking access to %s due to blacklist" % (ip_address,))
e = SynapseError(403, "IP address blocked by IP blacklist entry")
return defer.fail(Failure(e))
except Exception:
# Not an IP
pass
return self._agent.request(
method, uri, headers=headers, bodyProducer=bodyProducer
)
class SimpleHttpClient:
"""
A simple, no-frills HTTP client with methods that wrap up common ways of
using HTTP in Matrix
"""
def __init__(
self,
hs: "HomeServer",
treq_args: Dict[str, Any] = {},
ip_whitelist: Optional[IPSet] = None,
ip_blacklist: Optional[IPSet] = None,
http_proxy: Optional[bytes] = None,
https_proxy: Optional[bytes] = None,
):
"""
Args:
hs
treq_args: Extra keyword arguments to be given to treq.request.
ip_blacklist: The IP addresses that are blacklisted that
we may not request.
ip_whitelist: The whitelisted IP addresses, that we can
request if it were otherwise caught in a blacklist.
http_proxy: proxy server to use for http connections. host[:port]
https_proxy: proxy server to use for https connections. host[:port]
"""
self.hs = hs
self._ip_whitelist = ip_whitelist
self._ip_blacklist = ip_blacklist
self._extra_treq_args = treq_args
self.user_agent = hs.version_string
self.clock = hs.get_clock()
if hs.config.user_agent_suffix:
self.user_agent = "%s %s" % (self.user_agent, hs.config.user_agent_suffix)
# We use this for our body producers to ensure that they use the correct
# reactor.
self._cooperator = Cooperator(scheduler=_make_scheduler(hs.get_reactor()))
self.user_agent = self.user_agent.encode("ascii")
if self._ip_blacklist:
# If we have an IP blacklist, we need to use a DNS resolver which
# filters out blacklisted IP addresses, to prevent DNS rebinding.
self.reactor = BlacklistingReactorWrapper(
hs.get_reactor(), self._ip_whitelist, self._ip_blacklist
)
else:
self.reactor = hs.get_reactor()
# the pusher makes lots of concurrent SSL connections to sygnal, and
# tends to do so in batches, so we need to allow the pool to keep
# lots of idle connections around.
pool = HTTPConnectionPool(self.reactor)
# XXX: The justification for using the cache factor here is that larger instances
# will need both more cache and more connections.
# Still, this should probably be a separate dial
pool.maxPersistentPerHost = max((100 * hs.config.caches.global_factor, 5))
pool.cachedConnectionTimeout = 2 * 60
self.agent = ProxyAgent(
self.reactor,
connectTimeout=15,
contextFactory=self.hs.get_http_client_context_factory(),
pool=pool,
http_proxy=http_proxy,
https_proxy=https_proxy,
)
if self._ip_blacklist:
# If we have an IP blacklist, we then install the blacklisting Agent
# which prevents direct access to IP addresses, that are not caught
# by the DNS resolution.
self.agent = BlacklistingAgentWrapper(
self.agent,
ip_whitelist=self._ip_whitelist,
ip_blacklist=self._ip_blacklist,
)
async def request(
self,
method: str,
uri: str,
data: Optional[bytes] = None,
headers: Optional[Headers] = None,
) -> IResponse:
"""
Args:
method: HTTP method to use.
uri: URI to query.
data: Data to send in the request body, if applicable.
headers: Request headers.
Returns:
Response object, once the headers have been read.
Raises:
RequestTimedOutError if the request times out before the headers are read
"""
outgoing_requests_counter.labels(method).inc()
# log request but strip `access_token` (AS requests for example include this)
logger.debug("Sending request %s %s", method, redact_uri(uri))
with start_active_span(
"outgoing-client-request",
tags={
tags.SPAN_KIND: tags.SPAN_KIND_RPC_CLIENT,
tags.HTTP_METHOD: method,
tags.HTTP_URL: uri,
},
finish_on_close=True,
):
try:
body_producer = None
if data is not None:
body_producer = QuieterFileBodyProducer(
BytesIO(data), cooperator=self._cooperator,
)
request_deferred = treq.request(
method,
uri,
agent=self.agent,
data=body_producer,
headers=headers,
**self._extra_treq_args,
) # type: defer.Deferred
# we use our own timeout mechanism rather than treq's as a workaround
# for https://twistedmatrix.com/trac/ticket/9534.
request_deferred = timeout_deferred(
request_deferred, 60, self.hs.get_reactor(),
)
# turn timeouts into RequestTimedOutErrors
request_deferred.addErrback(_timeout_to_request_timed_out_error)
response = await make_deferred_yieldable(request_deferred)
incoming_responses_counter.labels(method, response.code).inc()
logger.info(
"Received response to %s %s: %s",
method,
redact_uri(uri),
response.code,
)
return response
except Exception as e:
incoming_responses_counter.labels(method, "ERR").inc()
logger.info(
"Error sending request to %s %s: %s %s",
method,
redact_uri(uri),
type(e).__name__,
e.args[0],
)
set_tag(tags.ERROR, True)
set_tag("error_reason", e.args[0])
raise
async def post_urlencoded_get_json(
self,
uri: str,
args: Optional[Mapping[str, Union[str, List[str]]]] = None,
headers: Optional[RawHeaders] = None,
) -> Any:
"""
Args:
uri: uri to query
args: parameters to be url-encoded in the body
headers: a map from header name to a list of values for that header
Returns:
parsed json
Raises:
RequestTimedOutError: if there is a timeout before the response headers
are received. Note there is currently no timeout on reading the response
body.
HttpResponseException: On a non-2xx HTTP response.
ValueError: if the response was not JSON
"""
# TODO: Do we ever want to log message contents?
logger.debug("post_urlencoded_get_json args: %s", args)
query_bytes = encode_query_args(args)
actual_headers = {
b"Content-Type": [b"application/x-www-form-urlencoded"],
b"User-Agent": [self.user_agent],
b"Accept": [b"application/json"],
}
if headers:
actual_headers.update(headers) # type: ignore
response = await self.request(
"POST", uri, headers=Headers(actual_headers), data=query_bytes
)
body = await make_deferred_yieldable(readBody(response))
if 200 <= response.code < 300:
return json_decoder.decode(body.decode("utf-8"))
else:
raise HttpResponseException(
response.code, response.phrase.decode("ascii", errors="replace"), body
)
async def post_json_get_json(
self, uri: str, post_json: Any, headers: Optional[RawHeaders] = None
) -> Any:
"""
Args:
uri: URI to query.
post_json: request body, to be encoded as json
headers: a map from header name to a list of values for that header
Returns:
parsed json
Raises:
RequestTimedOutError: if there is a timeout before the response headers
are received. Note there is currently no timeout on reading the response
body.
HttpResponseException: On a non-2xx HTTP response.
ValueError: if the response was not JSON
"""
json_str = encode_canonical_json(post_json)
logger.debug("HTTP POST %s -> %s", json_str, uri)
actual_headers = {
b"Content-Type": [b"application/json"],
b"User-Agent": [self.user_agent],
b"Accept": [b"application/json"],
}
if headers:
actual_headers.update(headers) # type: ignore
response = await self.request(
"POST", uri, headers=Headers(actual_headers), data=json_str
)
body = await make_deferred_yieldable(readBody(response))
if 200 <= response.code < 300:
return json_decoder.decode(body.decode("utf-8"))
else:
raise HttpResponseException(
response.code, response.phrase.decode("ascii", errors="replace"), body
)
async def get_json(
self,
uri: str,
args: Optional[QueryParams] = None,
headers: Optional[RawHeaders] = None,
) -> Any:
"""Gets some json from the given URI.
Args:
uri: The URI to request, not including query parameters
args: A dictionary used to create query string
headers: a map from header name to a list of values for that header
Returns:
Succeeds when we get a 2xx HTTP response, with the HTTP body as JSON.
Raises:
RequestTimedOutError: if there is a timeout before the response headers
are received. Note there is currently no timeout on reading the response
body.
HttpResponseException On a non-2xx HTTP response.
ValueError: if the response was not JSON
"""
actual_headers = {b"Accept": [b"application/json"]}
if headers:
actual_headers.update(headers) # type: ignore
body = await self.get_raw(uri, args, headers=headers)
return json_decoder.decode(body.decode("utf-8"))
async def put_json(
self,
uri: str,
json_body: Any,
args: Optional[QueryParams] = None,
headers: RawHeaders = None,
) -> Any:
"""Puts some json to the given URI.
Args:
uri: The URI to request, not including query parameters
json_body: The JSON to put in the HTTP body,
args: A dictionary used to create query strings
headers: a map from header name to a list of values for that header
Returns:
Succeeds when we get a 2xx HTTP response, with the HTTP body as JSON.
Raises:
RequestTimedOutError: if there is a timeout before the response headers
are received. Note there is currently no timeout on reading the response
body.
HttpResponseException On a non-2xx HTTP response.
ValueError: if the response was not JSON
"""
if args:
query_str = urllib.parse.urlencode(args, True)
uri = "%s?%s" % (uri, query_str)
json_str = encode_canonical_json(json_body)
actual_headers = {
b"Content-Type": [b"application/json"],
b"User-Agent": [self.user_agent],
b"Accept": [b"application/json"],
}
if headers:
actual_headers.update(headers) # type: ignore
response = await self.request(
"PUT", uri, headers=Headers(actual_headers), data=json_str
)
body = await make_deferred_yieldable(readBody(response))
if 200 <= response.code < 300:
return json_decoder.decode(body.decode("utf-8"))
else:
raise HttpResponseException(
response.code, response.phrase.decode("ascii", errors="replace"), body
)
async def get_raw(
self,
uri: str,
args: Optional[QueryParams] = None,
headers: Optional[RawHeaders] = None,
) -> bytes:
"""Gets raw text from the given URI.
Args:
uri: The URI to request, not including query parameters
args: A dictionary used to create query strings
headers: a map from header name to a list of values for that header
Returns:
Succeeds when we get a 2xx HTTP response, with the
HTTP body as bytes.
Raises:
RequestTimedOutError: if there is a timeout before the response headers
are received. Note there is currently no timeout on reading the response
body.
HttpResponseException on a non-2xx HTTP response.
"""
if args:
query_str = urllib.parse.urlencode(args, True)
uri = "%s?%s" % (uri, query_str)
actual_headers = {b"User-Agent": [self.user_agent]}
if headers:
actual_headers.update(headers) # type: ignore
response = await self.request("GET", uri, headers=Headers(actual_headers))
body = await make_deferred_yieldable(readBody(response))
if 200 <= response.code < 300:
return body
else:
raise HttpResponseException(
response.code, response.phrase.decode("ascii", errors="replace"), body
)
# XXX: FIXME: This is horribly copy-pasted from matrixfederationclient.
# The two should be factored out.
async def get_file(
self,
url: str,
output_stream: BinaryIO,
max_size: Optional[int] = None,
headers: Optional[RawHeaders] = None,
) -> Tuple[int, Dict[bytes, List[bytes]], str, int]:
"""GETs a file from a given URL
Args:
url: The URL to GET
output_stream: File to write the response body to.
headers: A map from header name to a list of values for that header
Returns:
A tuple of the file length, dict of the response
headers, absolute URI of the response and HTTP response code.
Raises:
RequestTimedOutError: if there is a timeout before the response headers
are received. Note there is currently no timeout on reading the response
body.
SynapseError: if the response is not a 2xx, the remote file is too large, or
another exception happens during the download.
"""
actual_headers = {b"User-Agent": [self.user_agent]}
if headers:
actual_headers.update(headers) # type: ignore
response = await self.request("GET", url, headers=Headers(actual_headers))
resp_headers = dict(response.headers.getAllRawHeaders())
if (
b"Content-Length" in resp_headers
and max_size
and int(resp_headers[b"Content-Length"][0]) > max_size
):
logger.warning("Requested URL is too large > %r bytes" % (max_size,))
raise SynapseError(
502,
"Requested file is too large > %r bytes" % (max_size,),
Codes.TOO_LARGE,
)
if response.code > 299:
logger.warning("Got %d when downloading %s" % (response.code, url))
raise SynapseError(502, "Got error %d" % (response.code,), Codes.UNKNOWN)
# TODO: if our Content-Type is HTML or something, just read the first
# N bytes into RAM rather than saving it all to disk only to read it
# straight back in again
try:
length = await make_deferred_yieldable(
readBodyToFile(response, output_stream, max_size)
)
except SynapseError:
# This can happen e.g. because the body is too large.
raise
except Exception as e:
raise SynapseError(502, ("Failed to download remote body: %s" % e)) from e
return (
length,
resp_headers,
response.request.absoluteURI.decode("ascii"),
response.code,
)
def _timeout_to_request_timed_out_error(f: Failure):
if f.check(twisted_error.TimeoutError, twisted_error.ConnectingCancelledError):
# The TCP connection has its own timeout (set by the 'connectTimeout' param
# on the Agent), which raises twisted_error.TimeoutError exception.
raise RequestTimedOutError("Timeout connecting to remote server")
elif f.check(defer.TimeoutError, ResponseNeverReceived):
# this one means that we hit our overall timeout on the request
raise RequestTimedOutError("Timeout waiting for response from remote server")
return f
class _ReadBodyToFileProtocol(protocol.Protocol):
def __init__(
self, stream: BinaryIO, deferred: defer.Deferred, max_size: Optional[int]
):
self.stream = stream
self.deferred = deferred
self.length = 0
self.max_size = max_size
def dataReceived(self, data: bytes) -> None:
self.stream.write(data)
self.length += len(data)
if self.max_size is not None and self.length >= self.max_size:
self.deferred.errback(
SynapseError(
502,
"Requested file is too large > %r bytes" % (self.max_size,),
Codes.TOO_LARGE,
)
)
self.deferred = defer.Deferred()
self.transport.loseConnection()
def connectionLost(self, reason: Failure) -> None:
if reason.check(ResponseDone):
self.deferred.callback(self.length)
elif reason.check(PotentialDataLoss):
# stolen from https://github.com/twisted/treq/pull/49/files
# http://twistedmatrix.com/trac/ticket/4840
self.deferred.callback(self.length)
else:
self.deferred.errback(reason)
def readBodyToFile(
response: IResponse, stream: BinaryIO, max_size: Optional[int]
) -> defer.Deferred:
"""
Read a HTTP response body to a file-object. Optionally enforcing a maximum file size.
Args:
response: The HTTP response to read from.
stream: The file-object to write to.
max_size: The maximum file size to allow.
Returns:
A Deferred which resolves to the length of the read body.
"""
d = defer.Deferred()
response.deliverBody(_ReadBodyToFileProtocol(stream, d, max_size))
return d
def encode_query_args(args: Optional[Mapping[str, Union[str, List[str]]]]) -> bytes:
"""
Encodes a map of query arguments to bytes which can be appended to a URL.
Args:
args: The query arguments, a mapping of string to string or list of strings.
Returns:
The query arguments encoded as bytes.
"""
if args is None:
return b""
encoded_args = {}
for k, vs in args.items():
if isinstance(vs, str):
vs = [vs]
encoded_args[k] = [v.encode("utf8") for v in vs]
query_str = urllib.parse.urlencode(encoded_args, True)
return query_str.encode("utf8")
class InsecureInterceptableContextFactory(ssl.ContextFactory):
"""
Factory for PyOpenSSL SSL contexts which accepts any certificate for any domain.
Do not use this since it allows an attacker to intercept your communications.
"""
def __init__(self):
self._context = SSL.Context(SSL.SSLv23_METHOD)
self._context.set_verify(VERIFY_NONE, lambda *_: None)
def getContext(self, hostname=None, port=None):
return self._context
def creatorForNetloc(self, hostname, port):
return self
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