diff --git a/changelog.d/5895.feature b/changelog.d/5895.feature
new file mode 100644
index 0000000000..c394a3772c
--- /dev/null
+++ b/changelog.d/5895.feature
@@ -0,0 +1 @@
+Add config option to sign remote key query responses with a separate key.
diff --git a/docs/sample_config.yaml b/docs/sample_config.yaml
index 0c6be30e51..ae1cafc5f3 100644
--- a/docs/sample_config.yaml
+++ b/docs/sample_config.yaml
@@ -1027,6 +1027,14 @@ signing_key_path: "CONFDIR/SERVERNAME.signing.key"
#
#trusted_key_servers:
# - server_name: "matrix.org"
+#
+
+# The signing keys to use when acting as a trusted key server. If not specified
+# defaults to the server signing key.
+#
+# Can contain multiple keys, one per line.
+#
+#key_server_signing_keys_path: "key_server_signing_keys.key"
# Enable SAML2 for registration and login. Uses pysaml2.
diff --git a/synapse/config/key.py b/synapse/config/key.py
index fe8386985c..ba2199bceb 100644
--- a/synapse/config/key.py
+++ b/synapse/config/key.py
@@ -76,7 +76,7 @@ class KeyConfig(Config):
config_dir_path, config["server_name"] + ".signing.key"
)
- self.signing_key = self.read_signing_key(signing_key_path)
+ self.signing_key = self.read_signing_keys(signing_key_path, "signing_key")
self.old_signing_keys = self.read_old_signing_keys(
config.get("old_signing_keys", {})
@@ -85,6 +85,14 @@ class KeyConfig(Config):
config.get("key_refresh_interval", "1d")
)
+ key_server_signing_keys_path = config.get("key_server_signing_keys_path")
+ if key_server_signing_keys_path:
+ self.key_server_signing_keys = self.read_signing_keys(
+ key_server_signing_keys_path, "key_server_signing_keys_path"
+ )
+ else:
+ self.key_server_signing_keys = list(self.signing_key)
+
# if neither trusted_key_servers nor perspectives are given, use the default.
if "perspectives" not in config and "trusted_key_servers" not in config:
key_servers = [{"server_name": "matrix.org"}]
@@ -210,16 +218,34 @@ class KeyConfig(Config):
#
#trusted_key_servers:
# - server_name: "matrix.org"
+ #
+
+ # The signing keys to use when acting as a trusted key server. If not specified
+ # defaults to the server signing key.
+ #
+ # Can contain multiple keys, one per line.
+ #
+ #key_server_signing_keys_path: "key_server_signing_keys.key"
"""
% locals()
)
- def read_signing_key(self, signing_key_path):
- signing_keys = self.read_file(signing_key_path, "signing_key")
+ def read_signing_keys(self, signing_key_path, name):
+ """Read the signing keys in the given path.
+
+ Args:
+ signing_key_path (str)
+ name (str): Associated config key name
+
+ Returns:
+ list[SigningKey]
+ """
+
+ signing_keys = self.read_file(signing_key_path, name)
try:
return read_signing_keys(signing_keys.splitlines(True))
except Exception as e:
- raise ConfigError("Error reading signing_key: %s" % (str(e)))
+ raise ConfigError("Error reading %s: %s" % (name, str(e)))
def read_old_signing_keys(self, old_signing_keys):
keys = {}
diff --git a/synapse/crypto/keyring.py b/synapse/crypto/keyring.py
index 654accc843..7cfad192e8 100644
--- a/synapse/crypto/keyring.py
+++ b/synapse/crypto/keyring.py
@@ -29,7 +29,6 @@ from signedjson.key import (
from signedjson.sign import (
SignatureVerifyException,
encode_canonical_json,
- sign_json,
signature_ids,
verify_signed_json,
)
@@ -539,13 +538,7 @@ class BaseV2KeyFetcher(object):
verify_key=verify_key, valid_until_ts=key_data["expired_ts"]
)
- # re-sign the json with our own key, so that it is ready if we are asked to
- # give it out as a notary server
- signed_key_json = sign_json(
- response_json, self.config.server_name, self.config.signing_key[0]
- )
-
- signed_key_json_bytes = encode_canonical_json(signed_key_json)
+ key_json_bytes = encode_canonical_json(response_json)
yield make_deferred_yieldable(
defer.gatherResults(
@@ -557,7 +550,7 @@ class BaseV2KeyFetcher(object):
from_server=from_server,
ts_now_ms=time_added_ms,
ts_expires_ms=ts_valid_until_ms,
- key_json_bytes=signed_key_json_bytes,
+ key_json_bytes=key_json_bytes,
)
for key_id in verify_keys
],
diff --git a/synapse/rest/key/v2/remote_key_resource.py b/synapse/rest/key/v2/remote_key_resource.py
index 031a316693..55580bc59e 100644
--- a/synapse/rest/key/v2/remote_key_resource.py
+++ b/synapse/rest/key/v2/remote_key_resource.py
@@ -13,7 +13,9 @@
# limitations under the License.
import logging
-from io import BytesIO
+
+from canonicaljson import encode_canonical_json, json
+from signedjson.sign import sign_json
from twisted.internet import defer
@@ -95,6 +97,7 @@ class RemoteKey(DirectServeResource):
self.store = hs.get_datastore()
self.clock = hs.get_clock()
self.federation_domain_whitelist = hs.config.federation_domain_whitelist
+ self.config = hs.config
@wrap_json_request_handler
async def _async_render_GET(self, request):
@@ -214,15 +217,14 @@ class RemoteKey(DirectServeResource):
yield self.fetcher.get_keys(cache_misses)
yield self.query_keys(request, query, query_remote_on_cache_miss=False)
else:
- result_io = BytesIO()
- result_io.write(b'{"server_keys":')
- sep = b"["
- for json_bytes in json_results:
- result_io.write(sep)
- result_io.write(json_bytes)
- sep = b","
- if sep == b"[":
- result_io.write(sep)
- result_io.write(b"]}")
-
- respond_with_json_bytes(request, 200, result_io.getvalue())
+ signed_keys = []
+ for key_json in json_results:
+ key_json = json.loads(key_json)
+ for signing_key in self.config.key_server_signing_keys:
+ key_json = sign_json(key_json, self.config.server_name, signing_key)
+
+ signed_keys.append(key_json)
+
+ results = {"server_keys": signed_keys}
+
+ respond_with_json_bytes(request, 200, encode_canonical_json(results))
|
