1 files changed, 88 insertions, 0 deletions
diff --git a/synapse/config/federation.py b/synapse/config/federation.py
new file mode 100644
index 0000000000..2c77d8f85b
--- /dev/null
+++ b/synapse/config/federation.py
@@ -0,0 +1,88 @@
+# -*- coding: utf-8 -*-
+# Copyright 2020 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.
+
+from typing import Optional
+
+from netaddr import IPSet
+
+from ._base import Config, ConfigError
+
+
+class FederationConfig(Config):
+    section = "federation"
+
+    def read_config(self, config, **kwargs):
+        # FIXME: federation_domain_whitelist needs sytests
+        self.federation_domain_whitelist = None  # type: Optional[dict]
+        federation_domain_whitelist = config.get("federation_domain_whitelist", None)
+
+        if federation_domain_whitelist is not None:
+            # turn the whitelist into a hash for speed of lookup
+            self.federation_domain_whitelist = {}
+
+            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
+            )
+
+    def generate_config_section(self, config_dir_path, server_name, **kwargs):
+        return """\
+        # Restrict federation to the following whitelist of domains.
+        # N.B. we recommend also firewalling your federation listener to limit
+        # inbound federation traffic as early as possible, rather than relying
+        # purely on this application-layer restriction.  If not specified, the
+        # default is to whitelist everything.
+        #
+        #federation_domain_whitelist:
+        #  - lon.example.com
+        #  - 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.
+        #
+        # As of Synapse v1.4.0 this option also affects any outbound requests to identity
+        # servers provided by user input.
+        #
+        # (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'
+        """