synapse-product/synapse/http/client.py
Erik Johnston 95d38afe96 Don't log exception when failing to fetch remote content.
In particular, let's not log stack traces when we stop processing
becuase the response body was too large.
2019-06-07 12:39:10 +01:00

681 lines
23 KiB
Python

# -*- 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
from io import BytesIO
from six import raise_from, text_type
from six.moves import urllib
import treq
from canonicaljson import encode_canonical_json, json
from netaddr import IPAddress
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, protocol, ssl
from twisted.internet.interfaces import (
IReactorPluggableNameResolver,
IResolutionReceiver,
)
from twisted.python.failure import Failure
from twisted.web._newclient import ResponseDone
from twisted.web.client import Agent, HTTPConnectionPool, PartialDownloadError, readBody
from twisted.web.http import PotentialDataLoss
from twisted.web.http_headers import Headers
from synapse.api.errors import Codes, HttpResponseException, SynapseError
from synapse.http import (
QuieterFileBodyProducer,
cancelled_to_request_timed_out_error,
redact_uri,
)
from synapse.util.async_helpers import timeout_deferred
from synapse.util.caches import CACHE_SIZE_FACTOR
from synapse.util.logcontext import make_deferred_yieldable
logger = logging.getLogger(__name__)
outgoing_requests_counter = Counter("synapse_http_client_requests", "", ["method"])
incoming_responses_counter = Counter(
"synapse_http_client_responses", "", ["method", "code"]
)
def check_against_blacklist(ip_address, ip_whitelist, ip_blacklist):
"""
Args:
ip_address (netaddr.IPAddress)
ip_whitelist (netaddr.IPSet)
ip_blacklist (netaddr.IPSet)
"""
if ip_address in ip_blacklist:
if ip_whitelist is None or ip_address not in ip_whitelist:
return True
return False
class IPBlacklistingResolver(object):
"""
A proxy for reactor.nameResolver which only produces non-blacklisted IP
addresses, preventing DNS rebinding attacks on URL preview.
"""
def __init__(self, reactor, ip_whitelist, ip_blacklist):
"""
Args:
reactor (twisted.internet.reactor)
ip_whitelist (netaddr.IPSet)
ip_blacklist (netaddr.IPSet)
"""
self._reactor = reactor
self._ip_whitelist = ip_whitelist
self._ip_blacklist = ip_blacklist
def resolveHostName(self, recv, hostname, portNumber=0):
r = recv()
addresses = []
def _callback():
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(object):
@staticmethod
def resolutionBegan(resolutionInProgress):
pass
@staticmethod
def addressResolved(address):
addresses.append(address)
@staticmethod
def resolutionComplete():
_callback()
self._reactor.nameResolver.resolveHostName(
EndpointReceiver, hostname, portNumber=portNumber
)
return r
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, reactor, ip_whitelist=None, ip_blacklist=None):
"""
Args:
agent (twisted.web.client.Agent): The Agent to wrap.
reactor (twisted.internet.reactor)
ip_whitelist (netaddr.IPSet)
ip_blacklist (netaddr.IPSet)
"""
self._agent = agent
self._ip_whitelist = ip_whitelist
self._ip_blacklist = ip_blacklist
def request(self, method, uri, headers=None, bodyProducer=None):
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(object):
"""
A simple, no-frills HTTP client with methods that wrap up common ways of
using HTTP in Matrix
"""
def __init__(self, hs, treq_args={}, ip_whitelist=None, ip_blacklist=None):
"""
Args:
hs (synapse.server.HomeServer)
treq_args (dict): Extra keyword arguments to be given to treq.request.
ip_blacklist (netaddr.IPSet): The IP addresses that are blacklisted that
we may not request.
ip_whitelist (netaddr.IPSet): The whitelisted IP addresses, that we can
request if it were otherwise caught in a blacklist.
"""
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)
self.user_agent = self.user_agent.encode('ascii')
if self._ip_blacklist:
real_reactor = hs.get_reactor()
# If we have an IP blacklist, we need to use a DNS resolver which
# filters out blacklisted IP addresses, to prevent DNS rebinding.
nameResolver = IPBlacklistingResolver(
real_reactor, self._ip_whitelist, self._ip_blacklist
)
@implementer(IReactorPluggableNameResolver)
class Reactor(object):
def __getattr__(_self, attr):
if attr == "nameResolver":
return nameResolver
else:
return getattr(real_reactor, attr)
self.reactor = Reactor()
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)
pool.maxPersistentPerHost = max((100 * CACHE_SIZE_FACTOR, 5))
pool.cachedConnectionTimeout = 2 * 60
# The default context factory in Twisted 14.0.0 (which we require) is
# BrowserLikePolicyForHTTPS which will do regular cert validation
# 'like a browser'
self.agent = Agent(
self.reactor,
connectTimeout=15,
contextFactory=self.hs.get_http_client_context_factory(),
pool=pool,
)
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,
self.reactor,
ip_whitelist=self._ip_whitelist,
ip_blacklist=self._ip_blacklist,
)
@defer.inlineCallbacks
def request(self, method, uri, data=None, headers=None):
"""
Args:
method (str): HTTP method to use.
uri (str): URI to query.
data (bytes): Data to send in the request body, if applicable.
headers (t.w.http_headers.Headers): Request headers.
"""
# A small wrapper around self.agent.request() so we can easily attach
# counters to it
outgoing_requests_counter.labels(method).inc()
# log request but strip `access_token` (AS requests for example include this)
logger.info("Sending request %s %s", method, redact_uri(uri))
try:
body_producer = None
if data is not None:
body_producer = QuieterFileBodyProducer(BytesIO(data))
request_deferred = treq.request(
method,
uri,
agent=self.agent,
data=body_producer,
headers=headers,
**self._extra_treq_args
)
request_deferred = timeout_deferred(
request_deferred,
60,
self.hs.get_reactor(),
cancelled_to_request_timed_out_error,
)
response = yield 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
)
defer.returnValue(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],
)
raise
@defer.inlineCallbacks
def post_urlencoded_get_json(self, uri, args={}, headers=None):
"""
Args:
uri (str):
args (dict[str, str|List[str]]): query params
headers (dict[str, List[str]]|None): If not None, a map from
header name to a list of values for that header
Returns:
Deferred[object]: parsed json
Raises:
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 = urllib.parse.urlencode(encode_urlencode_args(args), True).encode(
"utf8"
)
actual_headers = {
b"Content-Type": [b"application/x-www-form-urlencoded"],
b"User-Agent": [self.user_agent],
}
if headers:
actual_headers.update(headers)
response = yield self.request(
"POST", uri, headers=Headers(actual_headers), data=query_bytes
)
body = yield make_deferred_yieldable(readBody(response))
if 200 <= response.code < 300:
defer.returnValue(json.loads(body))
else:
raise HttpResponseException(response.code, response.phrase, body)
@defer.inlineCallbacks
def post_json_get_json(self, uri, post_json, headers=None):
"""
Args:
uri (str):
post_json (object):
headers (dict[str, List[str]]|None): If not None, a map from
header name to a list of values for that header
Returns:
Deferred[object]: parsed json
Raises:
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],
}
if headers:
actual_headers.update(headers)
response = yield self.request(
"POST", uri, headers=Headers(actual_headers), data=json_str
)
body = yield make_deferred_yieldable(readBody(response))
if 200 <= response.code < 300:
defer.returnValue(json.loads(body))
else:
raise HttpResponseException(response.code, response.phrase, body)
@defer.inlineCallbacks
def get_json(self, uri, args={}, headers=None):
""" Gets some json from the given URI.
Args:
uri (str): The URI to request, not including query parameters
args (dict): A dictionary used to create query strings, defaults to
None.
**Note**: The value of each key is assumed to be an iterable
and *not* a string.
headers (dict[str, List[str]]|None): If not None, a map from
header name to a list of values for that header
Returns:
Deferred: Succeeds when we get *any* 2xx HTTP response, with the
HTTP body as JSON.
Raises:
HttpResponseException On a non-2xx HTTP response.
ValueError: if the response was not JSON
"""
body = yield self.get_raw(uri, args, headers=headers)
defer.returnValue(json.loads(body))
@defer.inlineCallbacks
def put_json(self, uri, json_body, args={}, headers=None):
""" Puts some json to the given URI.
Args:
uri (str): The URI to request, not including query parameters
json_body (dict): The JSON to put in the HTTP body,
args (dict): A dictionary used to create query strings, defaults to
None.
**Note**: The value of each key is assumed to be an iterable
and *not* a string.
headers (dict[str, List[str]]|None): If not None, a map from
header name to a list of values for that header
Returns:
Deferred: Succeeds when we get *any* 2xx HTTP response, with the
HTTP body as JSON.
Raises:
HttpResponseException On a non-2xx HTTP response.
ValueError: if the response was not JSON
"""
if len(args):
query_bytes = urllib.parse.urlencode(args, True)
uri = "%s?%s" % (uri, query_bytes)
json_str = encode_canonical_json(json_body)
actual_headers = {
b"Content-Type": [b"application/json"],
b"User-Agent": [self.user_agent],
}
if headers:
actual_headers.update(headers)
response = yield self.request(
"PUT", uri, headers=Headers(actual_headers), data=json_str
)
body = yield make_deferred_yieldable(readBody(response))
if 200 <= response.code < 300:
defer.returnValue(json.loads(body))
else:
raise HttpResponseException(response.code, response.phrase, body)
@defer.inlineCallbacks
def get_raw(self, uri, args={}, headers=None):
""" Gets raw text from the given URI.
Args:
uri (str): The URI to request, not including query parameters
args (dict): A dictionary used to create query strings, defaults to
None.
**Note**: The value of each key is assumed to be an iterable
and *not* a string.
headers (dict[str, List[str]]|None): If not None, a map from
header name to a list of values for that header
Returns:
Deferred: Succeeds when we get *any* 2xx HTTP response, with the
HTTP body at text.
Raises:
HttpResponseException on a non-2xx HTTP response.
"""
if len(args):
query_bytes = urllib.parse.urlencode(args, True)
uri = "%s?%s" % (uri, query_bytes)
actual_headers = {b"User-Agent": [self.user_agent]}
if headers:
actual_headers.update(headers)
response = yield self.request("GET", uri, headers=Headers(actual_headers))
body = yield make_deferred_yieldable(readBody(response))
if 200 <= response.code < 300:
defer.returnValue(body)
else:
raise HttpResponseException(response.code, response.phrase, body)
# XXX: FIXME: This is horribly copy-pasted from matrixfederationclient.
# The two should be factored out.
@defer.inlineCallbacks
def get_file(self, url, output_stream, max_size=None, headers=None):
"""GETs a file from a given URL
Args:
url (str): The URL to GET
output_stream (file): File to write the response body to.
headers (dict[str, List[str]]|None): If not None, a map from
header name to a list of values for that header
Returns:
A (int,dict,string,int) tuple of the file length, dict of the response
headers, absolute URI of the response and HTTP response code.
"""
actual_headers = {b"User-Agent": [self.user_agent]}
if headers:
actual_headers.update(headers)
response = yield self.request("GET", url, headers=Headers(actual_headers))
resp_headers = dict(response.headers.getAllRawHeaders())
if (
b'Content-Length' in resp_headers
and int(resp_headers[b'Content-Length'][0]) > max_size
):
logger.warn("Requested URL is too large > %r bytes" % (self.max_size,))
raise SynapseError(
502,
"Requested file is too large > %r bytes" % (self.max_size,),
Codes.TOO_LARGE,
)
if response.code > 299:
logger.warn("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 = yield 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_from(
SynapseError(
502, ("Failed to download remote body: %s" % e),
),
e
)
defer.returnValue(
(
length,
resp_headers,
response.request.absoluteURI.decode('ascii'),
response.code,
)
)
# XXX: FIXME: This is horribly copy-pasted from matrixfederationclient.
# The two should be factored out.
class _ReadBodyToFileProtocol(protocol.Protocol):
def __init__(self, stream, deferred, max_size):
self.stream = stream
self.deferred = deferred
self.length = 0
self.max_size = max_size
def dataReceived(self, data):
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):
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)
# XXX: FIXME: This is horribly copy-pasted from matrixfederationclient.
# The two should be factored out.
def _readBodyToFile(response, stream, max_size):
d = defer.Deferred()
response.deliverBody(_ReadBodyToFileProtocol(stream, d, max_size))
return d
class CaptchaServerHttpClient(SimpleHttpClient):
"""
Separate HTTP client for talking to google's captcha servers
Only slightly special because accepts partial download responses
used only by c/s api v1
"""
@defer.inlineCallbacks
def post_urlencoded_get_raw(self, url, args={}):
query_bytes = urllib.parse.urlencode(encode_urlencode_args(args), True)
response = yield self.request(
"POST",
url,
data=query_bytes,
headers=Headers(
{
b"Content-Type": [b"application/x-www-form-urlencoded"],
b"User-Agent": [self.user_agent],
}
),
)
try:
body = yield make_deferred_yieldable(readBody(response))
defer.returnValue(body)
except PartialDownloadError as e:
# twisted dislikes google's response, no content length.
defer.returnValue(e.response)
def encode_urlencode_args(args):
return {k: encode_urlencode_arg(v) for k, v in args.items()}
def encode_urlencode_arg(arg):
if isinstance(arg, text_type):
return arg.encode('utf-8')
elif isinstance(arg, list):
return [encode_urlencode_arg(i) for i in arg]
else:
return arg
def _print_ex(e):
if hasattr(e, "reasons") and e.reasons:
for ex in e.reasons:
_print_ex(ex)
else:
logger.exception(e)
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