diff --git a/synapse/federation/transport/client.py b/synapse/federation/transport/client.py
index dc563538de..c35637a571 100644
--- a/synapse/federation/transport/client.py
+++ b/synapse/federation/transport/client.py
@@ -406,13 +406,19 @@ class TransportLayerClient(object):
"device_keys": {
"<user_id>": {
"<device_id>": {...}
+ } }
+ "master_keys": {
+ "<user_id>": {...}
+ } }
+ "self_signing_keys": {
+ "<user_id>": {...}
} } }
Args:
destination(str): The server to query.
query_content(dict): The user ids to query.
Returns:
- A dict containg the device keys.
+ A dict containing device and cross-signing keys.
"""
path = _create_v1_path("/user/keys/query")
@@ -429,14 +435,16 @@ class TransportLayerClient(object):
Response:
{
"stream_id": "...",
- "devices": [ { ... } ]
+ "devices": [ { ... } ],
+ "master_key": { ... },
+ "self_signing_key: { ... }
}
Args:
destination(str): The server to query.
query_content(dict): The user ids to query.
Returns:
- A dict containg the device keys.
+ A dict containing device and cross-signing keys.
"""
path = _create_v1_path("/user/devices/%s", user_id)
diff --git a/synapse/handlers/e2e_keys.py b/synapse/handlers/e2e_keys.py
index 8d7075f2eb..afc173ab2f 100644
--- a/synapse/handlers/e2e_keys.py
+++ b/synapse/handlers/e2e_keys.py
@@ -16,6 +16,7 @@
# limitations under the License.
import logging
+from typing import Dict, Optional, Tuple
from six import iteritems
@@ -23,6 +24,7 @@ import attr
from canonicaljson import encode_canonical_json, json
from signedjson.key import decode_verify_key_bytes
from signedjson.sign import SignatureVerifyException, verify_signed_json
+from signedjson.types import VerifyKey
from unpaddedbase64 import decode_base64
from twisted.internet import defer
@@ -174,8 +176,8 @@ class E2eKeysHandler(object):
"""This is called when we are querying the device list of a user on
a remote homeserver and their device list is not in the device list
cache. If we share a room with this user and we're not querying for
- specific user we will update the cache
- with their device list."""
+ specific user we will update the cache with their device list.
+ """
destination_query = remote_queries_not_in_cache[destination]
@@ -961,13 +963,19 @@ class E2eKeysHandler(object):
return signature_list, failures
@defer.inlineCallbacks
- def _get_e2e_cross_signing_verify_key(self, user_id, key_type, from_user_id=None):
- """Fetch the cross-signing public key from storage and interpret it.
+ def _get_e2e_cross_signing_verify_key(
+ self, user_id: str, key_type: str, from_user_id: str = None
+ ):
+ """Fetch locally or remotely query for a cross-signing public key.
+
+ First, attempt to fetch the cross-signing public key from storage.
+ If that fails, query the keys from the homeserver they belong to
+ and update our local copy.
Args:
- user_id (str): the user whose key should be fetched
- key_type (str): the type of key to fetch
- from_user_id (str): the user that we are fetching the keys for.
+ user_id: the user whose key should be fetched
+ key_type: the type of key to fetch
+ from_user_id: the user that we are fetching the keys for.
This affects what signatures are fetched.
Returns:
@@ -976,16 +984,128 @@ class E2eKeysHandler(object):
Raises:
NotFoundError: if the key is not found
+ SynapseError: if `user_id` is invalid
"""
+ user = UserID.from_string(user_id)
+ key_id = None
+ verify_key = None
+
key = yield self.store.get_e2e_cross_signing_key(
user_id, key_type, from_user_id
)
+
+ # If we couldn't find the key locally, and we're looking for keys of
+ # another user then attempt to fetch the missing key from the remote
+ # user's server.
+ #
+ # We may run into this in possible edge cases where a user tries to
+ # cross-sign a remote user, but does not share any rooms with them yet.
+ # Thus, we would not have their key list yet. We fetch the key here,
+ # store it and notify clients of new, associated device IDs.
+ if (
+ key is None
+ and not self.is_mine(user)
+ # We only get "master" and "self_signing" keys from remote servers
+ and key_type in ["master", "self_signing"]
+ ):
+ key = yield self._retrieve_cross_signing_keys_for_remote_user(
+ user, key_type
+ )
+
if key is None:
- logger.debug("no %s key found for %s", key_type, user_id)
+ logger.debug("No %s key found for %s", key_type, user_id)
raise NotFoundError("No %s key found for %s" % (key_type, user_id))
- key_id, verify_key = get_verify_key_from_cross_signing_key(key)
+
+ # If we retrieved the keys remotely, these values will already be set
+ if key_id is None or verify_key is None:
+ try:
+ key_id, verify_key = get_verify_key_from_cross_signing_key(key)
+ except ValueError as e:
+ logger.debug(
+ "Invalid %s key retrieved: %s - %s %s", key_type, key, type(e), e,
+ )
+ raise SynapseError(
+ 502, "Invalid %s key retrieved from remote server", key_type
+ )
+
return key, key_id, verify_key
+ @defer.inlineCallbacks
+ def _retrieve_cross_signing_keys_for_remote_user(
+ self, user: UserID, desired_key_type: str,
+ ) -> Tuple[Optional[Dict], Optional[str], Optional[VerifyKey]]:
+ """Queries cross-signing keys for a remote user and saves them to the database
+
+ Only the key specified by `key_type` will be returned, while all retrieved keys
+ will be saved regardless
+
+ Args:
+ user: The user to query remote keys for
+ desired_key_type: The type of key to receive. One of "master", "self_signing"
+
+ Returns:
+ A tuple of the retrieved key content, the key's ID and the matching VerifyKey.
+ If the key cannot be retrieved, all values in the tuple will instead be None.
+ """
+ try:
+ remote_result = yield self.federation.query_user_devices(
+ user.domain, user.to_string()
+ )
+ except Exception as e:
+ logger.warning(
+ "Unable to query %s for cross-signing keys of user %s: %s %s",
+ user.domain,
+ user.to_string(),
+ type(e),
+ e,
+ )
+ return None
+
+ # Process each of the retrieved cross-signing keys
+ final_key = None
+ final_key_id = None
+ final_verify_key = None
+ device_ids = []
+ for key_type in ["master", "self_signing"]:
+ key_content = remote_result.get(key_type + "_key")
+ if not key_content:
+ continue
+
+ # At the same time, store this key in the db for
+ # subsequent queries
+ yield self.store.set_e2e_cross_signing_key(
+ user.to_string(), key_type, key_content
+ )
+
+ # Note down the device ID attached to this key
+ try:
+ # verify_key is a VerifyKey from signedjson, which uses
+ # .version to denote the portion of the key ID after the
+ # algorithm and colon, which is the device ID
+ key_id, verify_key = get_verify_key_from_cross_signing_key(key_content)
+ except ValueError as e:
+ logger.debug(
+ "Invalid %s key retrieved: %s - %s %s",
+ key_type,
+ key_content,
+ type(e),
+ e,
+ )
+ continue
+ device_ids.append(verify_key.version)
+
+ # If this is the desired key type, save it and it's ID/VerifyKey
+ if key_type == desired_key_type:
+ final_key = key_content
+ final_verify_key = verify_key
+ final_key_id = key_id
+
+ # Notify clients that new devices for this user have been discovered
+ if device_ids:
+ yield self.device_handler.notify_device_update(user.to_string(), device_ids)
+
+ return final_key, final_key_id, final_verify_key
+
def _check_cross_signing_key(key, user_id, key_type, signing_key=None):
"""Check a cross-signing key uploaded by a user. Performs some basic sanity
|
