diff options
| -rw-r--r-- | changelog.d/5043.feature | 1 | ||||
| -rw-r--r-- | docs/sample_config.yaml | 18 | ||||
| -rw-r--r-- | synapse/config/server.py | 38 | ||||
| -rw-r--r-- | synapse/http/client.py | 6 | ||||
| -rw-r--r-- | synapse/http/matrixfederationclient.py | 48 | ||||
| -rw-r--r-- | tests/http/test_fedclient.py | 71 |
6 files changed, 168 insertions, 14 deletions
diff --git a/changelog.d/5043.feature b/changelog.d/5043.feature new file mode 100644 index 0000000000..0f1e0ee30e --- /dev/null +++ b/changelog.d/5043.feature @@ -0,0 +1 @@ +Add ability to blacklist IP ranges for the federation client. diff --git a/docs/sample_config.yaml b/docs/sample_config.yaml index bdfc34c6bd..c4e5c4cf39 100644 --- a/docs/sample_config.yaml +++ b/docs/sample_config.yaml @@ -115,6 +115,24 @@ pid_file: DATADIR/homeserver.pid # - nyc.example.com # - syd.example.com +# Prevent federation requests from being sent to the following +# blacklist IP address CIDR ranges. If this option is not specified, or +# specified with an empty list, no ip range blacklist will be enforced. +# +# (0.0.0.0 and :: are always blacklisted, whether or not they are explicitly +# listed here, since they correspond to unroutable addresses.) +# +federation_ip_range_blacklist: + - '127.0.0.0/8' + - '10.0.0.0/8' + - '172.16.0.0/12' + - '192.168.0.0/16' + - '100.64.0.0/10' + - '169.254.0.0/16' + - '::1/128' + - 'fe80::/64' + - 'fc00::/7' + # List of ports that Synapse should listen on, their purpose and their # configuration. # diff --git a/synapse/config/server.py b/synapse/config/server.py index 8dce75c56a..7874cd9da7 100644 --- a/synapse/config/server.py +++ b/synapse/config/server.py @@ -17,6 +17,8 @@ import logging import os.path +from netaddr import IPSet + from synapse.http.endpoint import parse_and_validate_server_name from synapse.python_dependencies import DependencyException, check_requirements @@ -137,6 +139,24 @@ class ServerConfig(Config): for domain in federation_domain_whitelist: self.federation_domain_whitelist[domain] = True + self.federation_ip_range_blacklist = config.get( + "federation_ip_range_blacklist", [], + ) + + # Attempt to create an IPSet from the given ranges + try: + self.federation_ip_range_blacklist = IPSet( + self.federation_ip_range_blacklist + ) + + # Always blacklist 0.0.0.0, :: + self.federation_ip_range_blacklist.update(["0.0.0.0", "::"]) + except Exception as e: + raise ConfigError( + "Invalid range(s) provided in " + "federation_ip_range_blacklist: %s" % e + ) + if self.public_baseurl is not None: if self.public_baseurl[-1] != '/': self.public_baseurl += '/' @@ -386,6 +406,24 @@ class ServerConfig(Config): # - nyc.example.com # - syd.example.com + # Prevent federation requests from being sent to the following + # blacklist IP address CIDR ranges. If this option is not specified, or + # specified with an empty list, no ip range blacklist will be enforced. + # + # (0.0.0.0 and :: are always blacklisted, whether or not they are explicitly + # listed here, since they correspond to unroutable addresses.) + # + federation_ip_range_blacklist: + - '127.0.0.0/8' + - '10.0.0.0/8' + - '172.16.0.0/12' + - '192.168.0.0/16' + - '100.64.0.0/10' + - '169.254.0.0/16' + - '::1/128' + - 'fe80::/64' + - 'fc00::/7' + # List of ports that Synapse should listen on, their purpose and their # configuration. # diff --git a/synapse/http/client.py b/synapse/http/client.py index ddbfb72228..77fe68818b 100644 --- a/synapse/http/client.py +++ b/synapse/http/client.py @@ -165,7 +165,8 @@ class BlacklistingAgentWrapper(Agent): ip_address, self._ip_whitelist, self._ip_blacklist ): logger.info( - "Blocking access to %s because of blacklist" % (ip_address,) + "Blocking access to %s due to blacklist" % + (ip_address,) ) e = SynapseError(403, "IP address blocked by IP blacklist entry") return defer.fail(Failure(e)) @@ -263,9 +264,6 @@ class SimpleHttpClient(object): uri (str): URI to query. data (bytes): Data to send in the request body, if applicable. headers (t.w.http_headers.Headers): Request headers. - - Raises: - SynapseError: If the IP is blacklisted. """ # A small wrapper around self.agent.request() so we can easily attach # counters to it diff --git a/synapse/http/matrixfederationclient.py b/synapse/http/matrixfederationclient.py index ff63d0b2a8..7eefc7b1fc 100644 --- a/synapse/http/matrixfederationclient.py +++ b/synapse/http/matrixfederationclient.py @@ -27,9 +27,11 @@ import treq from canonicaljson import encode_canonical_json from prometheus_client import Counter from signedjson.sign import sign_json +from zope.interface import implementer from twisted.internet import defer, protocol from twisted.internet.error import DNSLookupError +from twisted.internet.interfaces import IReactorPluggableNameResolver from twisted.internet.task import _EPSILON, Cooperator from twisted.web._newclient import ResponseDone from twisted.web.http_headers import Headers @@ -44,6 +46,7 @@ from synapse.api.errors import ( SynapseError, ) from synapse.http import QuieterFileBodyProducer +from synapse.http.client import BlacklistingAgentWrapper, IPBlacklistingResolver from synapse.http.federation.matrix_federation_agent import MatrixFederationAgent from synapse.util.async_helpers import timeout_deferred from synapse.util.logcontext import make_deferred_yieldable @@ -172,19 +175,44 @@ class MatrixFederationHttpClient(object): self.hs = hs self.signing_key = hs.config.signing_key[0] self.server_name = hs.hostname - reactor = hs.get_reactor() + + real_reactor = hs.get_reactor() + + # We need to use a DNS resolver which filters out blacklisted IP + # addresses, to prevent DNS rebinding. + nameResolver = IPBlacklistingResolver( + real_reactor, None, hs.config.federation_ip_range_blacklist, + ) + + @implementer(IReactorPluggableNameResolver) + class Reactor(object): + def __getattr__(_self, attr): + if attr == "nameResolver": + return nameResolver + else: + return getattr(real_reactor, attr) + + self.reactor = Reactor() self.agent = MatrixFederationAgent( - hs.get_reactor(), + self.reactor, tls_client_options_factory, ) + + # Use a BlacklistingAgentWrapper to prevent circumventing the IP + # blacklist via IP literals in server names + self.agent = BlacklistingAgentWrapper( + self.agent, self.reactor, + ip_blacklist=hs.config.federation_ip_range_blacklist, + ) + self.clock = hs.get_clock() self._store = hs.get_datastore() self.version_string_bytes = hs.version_string.encode('ascii') self.default_timeout = 60 def schedule(x): - reactor.callLater(_EPSILON, x) + self.reactor.callLater(_EPSILON, x) self._cooperator = Cooperator(scheduler=schedule) @@ -370,7 +398,7 @@ class MatrixFederationHttpClient(object): request_deferred = timeout_deferred( request_deferred, timeout=_sec_timeout, - reactor=self.hs.get_reactor(), + reactor=self.reactor, ) response = yield request_deferred @@ -397,7 +425,7 @@ class MatrixFederationHttpClient(object): d = timeout_deferred( d, timeout=_sec_timeout, - reactor=self.hs.get_reactor(), + reactor=self.reactor, ) try: @@ -586,7 +614,7 @@ class MatrixFederationHttpClient(object): ) body = yield _handle_json_response( - self.hs.get_reactor(), self.default_timeout, request, response, + self.reactor, self.default_timeout, request, response, ) defer.returnValue(body) @@ -645,7 +673,7 @@ class MatrixFederationHttpClient(object): _sec_timeout = self.default_timeout body = yield _handle_json_response( - self.hs.get_reactor(), _sec_timeout, request, response, + self.reactor, _sec_timeout, request, response, ) defer.returnValue(body) @@ -704,7 +732,7 @@ class MatrixFederationHttpClient(object): ) body = yield _handle_json_response( - self.hs.get_reactor(), self.default_timeout, request, response, + self.reactor, self.default_timeout, request, response, ) defer.returnValue(body) @@ -753,7 +781,7 @@ class MatrixFederationHttpClient(object): ) body = yield _handle_json_response( - self.hs.get_reactor(), self.default_timeout, request, response, + self.reactor, self.default_timeout, request, response, ) defer.returnValue(body) @@ -801,7 +829,7 @@ class MatrixFederationHttpClient(object): try: d = _readBodyToFile(response, output_stream, max_size) - d.addTimeout(self.default_timeout, self.hs.get_reactor()) + d.addTimeout(self.default_timeout, self.reactor) length = yield make_deferred_yieldable(d) except Exception as e: logger.warn( diff --git a/tests/http/test_fedclient.py b/tests/http/test_fedclient.py index 279e456614..ee767f3a5a 100644 --- a/tests/http/test_fedclient.py +++ b/tests/http/test_fedclient.py @@ -15,6 +15,8 @@ from mock import Mock +from netaddr import IPSet + from twisted.internet import defer from twisted.internet.defer import TimeoutError from twisted.internet.error import ConnectingCancelledError, DNSLookupError @@ -209,6 +211,75 @@ class FederationClientTests(HomeserverTestCase): self.assertIsInstance(f.value, RequestSendFailed) self.assertIsInstance(f.value.inner_exception, ResponseNeverReceived) + def test_client_ip_range_blacklist(self): + """Ensure that Synapse does not try to connect to blacklisted IPs""" + + # Set up the ip_range blacklist + self.hs.config.federation_ip_range_blacklist = IPSet([ + "127.0.0.0/8", + "fe80::/64", + ]) + self.reactor.lookups["internal"] = "127.0.0.1" + self.reactor.lookups["internalv6"] = "fe80:0:0:0:0:8a2e:370:7337" + self.reactor.lookups["fine"] = "10.20.30.40" + cl = MatrixFederationHttpClient(self.hs, None) + + # Try making a GET request to a blacklisted IPv4 address + # ------------------------------------------------------ + # Make the request + d = cl.get_json("internal:8008", "foo/bar", timeout=10000) + + # Nothing happened yet + self.assertNoResult(d) + + self.pump(1) + + # Check that it was unable to resolve the address + clients = self.reactor.tcpClients + self.assertEqual(len(clients), 0) + + f = self.failureResultOf(d) + self.assertIsInstance(f.value, RequestSendFailed) + self.assertIsInstance(f.value.inner_exception, DNSLookupError) + + # Try making a POST request to a blacklisted IPv6 address + # ------------------------------------------------------- + # Make the request + d = cl.post_json("internalv6:8008", "foo/bar", timeout=10000) + + # Nothing has happened yet + self.assertNoResult(d) + + # Move the reactor forwards + self.pump(1) + + # Check that it was unable to resolve the address + clients = self.reactor.tcpClients + self.assertEqual(len(clients), 0) + + # Check that it was due to a blacklisted DNS lookup + f = self.failureResultOf(d, RequestSendFailed) + self.assertIsInstance(f.value.inner_exception, DNSLookupError) + + # Try making a GET request to a non-blacklisted IPv4 address + # ---------------------------------------------------------- + # Make the request + d = cl.post_json("fine:8008", "foo/bar", timeout=10000) + + # Nothing has happened yet + self.assertNoResult(d) + + # Move the reactor forwards + self.pump(1) + + # Check that it was able to resolve the address + clients = self.reactor.tcpClients + self.assertNotEqual(len(clients), 0) + + # Connection will still fail as this IP address does not resolve to anything + f = self.failureResultOf(d, RequestSendFailed) + self.assertIsInstance(f.value.inner_exception, ConnectingCancelledError) + def test_client_gets_headers(self): """ Once the client gets the headers, _request returns successfully. |