diff --git a/synapse/handlers/e2e_keys.py b/synapse/handlers/e2e_keys.py
index 997ad66f8f..9747b517ff 100644
--- a/synapse/handlers/e2e_keys.py
+++ b/synapse/handlers/e2e_keys.py
@@ -608,6 +608,194 @@ class E2eKeysHandler(object):
return {}
+ @defer.inlineCallbacks
+ def upload_signatures_for_device_keys(self, user_id, signatures):
+ """Upload device signatures for cross-signing
+
+ Args:
+ user_id (string): the user uploading the signatures
+ signatures (dict[string, dict[string, dict]]): map of users to
+ devices to signed keys
+ """
+ failures = {}
+
+ signature_list = [] # signatures to be stored
+ self_device_ids = [] # what devices have been updated, for notifying
+
+ # split between checking signatures for own user and signatures for
+ # other users, since we verify them with different keys
+ if user_id in signatures:
+ self_signatures = signatures[user_id]
+ del signatures[user_id]
+ self_device_ids = list(self_signatures.keys())
+ try:
+ # get our self-signing key to verify the signatures
+ self_signing_key = yield self.store.get_e2e_cross_signing_key(
+ user_id, "self_signing"
+ )
+ if self_signing_key is None:
+ raise SynapseError(
+ 404,
+ "No self-signing key found",
+ Codes.NOT_FOUND
+ )
+
+ self_signing_key_id, self_signing_verify_key \
+ = get_verify_key_from_cross_signing_key(self_signing_key)
+
+ # fetch our stored devices so that we can compare with what was sent
+ user_devices = []
+ for device in self_signatures.keys():
+ user_devices.append((user_id, device))
+ devices = yield self.store.get_e2e_device_keys(user_devices)
+
+ if user_id not in devices:
+ raise SynapseError(
+ 404,
+ "No device key found",
+ Codes.NOT_FOUND
+ )
+
+ devices = devices[user_id]
+ for device_id, device in self_signatures.items():
+ try:
+ if ("signatures" not in device or
+ user_id not in device["signatures"] or
+ self_signing_key_id not in device["signatures"][user_id]):
+ # no signature was sent
+ raise SynapseError(
+ 400,
+ "Invalid signature",
+ Codes.INVALID_SIGNATURE
+ )
+
+ stored_device = devices[device_id]["keys"]
+ if self_signing_key_id in stored_device.get("signatures", {}) \
+ .get(user_id, {}):
+ # we already have a signature on this device, so we
+ # can skip it, since it should be exactly the same
+ continue
+
+ _check_device_signature(
+ user_id, self_signing_verify_key, device, stored_device
+ )
+
+ signature = device["signatures"][user_id][self_signing_key_id]
+ signature_list.append(
+ (self_signing_key_id, user_id, device_id, signature)
+ )
+ except SynapseError as e:
+ failures.setdefault(user_id, {})[device_id] \
+ = _exception_to_failure(e)
+ except SynapseError as e:
+ failures[user_id] = {
+ device: _exception_to_failure(e)
+ for device in self_signatures.keys()
+ }
+
+ signed_users = [] # what user have been signed, for notifying
+ if len(signatures):
+ # if signatures isn't empty, then we have signatures for other
+ # users. These signatures will be signed by the user signing key
+
+ # get our user-signing key to verify the signatures
+ user_signing_key = yield self.store.get_e2e_cross_signing_key(
+ user_id, "user_signing"
+ )
+ if user_signing_key is None:
+ for user, devicemap in signatures.items():
+ failures[user] = {
+ device: _exception_to_failure(SynapseError(
+ 404,
+ "No user-signing key found",
+ Codes.NOT_FOUND
+ ))
+ for device in devicemap.keys()
+ }
+ else:
+ user_signing_key_id, user_signing_verify_key \
+ = get_verify_key_from_cross_signing_key(user_signing_key)
+
+ for user, devicemap in signatures.items():
+ device_id = None
+ try:
+ # get the user's master key, to make sure it matches
+ # what was sent
+ stored_key = yield self.store.get_e2e_cross_signing_key(
+ user, "master", user_id
+ )
+ if stored_key is None:
+ logger.error(
+ "upload signature: no user key found for %s", user
+ )
+ raise SynapseError(
+ 404,
+ "User's master key not found",
+ Codes.NOT_FOUND
+ )
+
+ # make sure that the user's master key is the one that
+ # was signed (and no others)
+ device_id = get_verify_key_from_cross_signing_key(stored_key)[0] \
+ .split(":", 1)[1]
+ if device_id not in devicemap:
+ logger.error(
+ "upload signature: wrong device: %s vs %s",
+ device, devicemap
+ )
+ raise SynapseError(
+ 404,
+ "Unknown device",
+ Codes.NOT_FOUND
+ )
+ if len(devicemap) > 1:
+ logger.error("upload signature: too many devices specified")
+ failures[user] = {
+ device: _exception_to_failure(SynapseError(
+ 404,
+ "Unknown device",
+ Codes.NOT_FOUND
+ ))
+ for device in devicemap.keys()
+ }
+
+ key = devicemap[device_id]
+
+ if user_signing_key_id in stored_key.get("signatures", {}) \
+ .get(user_id, {}):
+ # we already have the signature, so we can skip it
+ continue
+
+ _check_device_signature(
+ user_id, user_signing_verify_key, key, stored_key
+ )
+
+ signature = key["signatures"][user_id][user_signing_key_id]
+
+ signed_users.append(user)
+ signature_list.append(
+ (user_signing_key_id, user, device_id, signature)
+ )
+ except SynapseError as e:
+ if device_id is None:
+ failures[user] = {
+ device_id: _exception_to_failure(e)
+ for device_id in devicemap.keys()
+ }
+ else:
+ failures.setdefault(user, {})[device_id] \
+ = _exception_to_failure(e)
+
+ # store the signature, and send the appropriate notifications for sync
+ logger.debug("upload signature failures: %r", failures)
+ yield self.store.store_e2e_device_signatures(user_id, signature_list)
+
+ if len(self_device_ids):
+ yield self.device_handler.notify_device_update(user_id, self_device_ids)
+ if len(signed_users):
+ yield self.device_handler.notify_user_signature_update(user_id, signed_users)
+
+ defer.returnValue({"failures": failures})
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
@@ -636,6 +824,68 @@ def _check_cross_signing_key(key, user_id, key_type, signing_key=None):
)
+def _check_device_signature(user_id, verify_key, signed_device, stored_device):
+ """Check that a device signature is correct and matches the copy of the device
+ that we have. Throws an exception if an error is detected.
+
+ Args:
+ user_id (str): the user ID whose signature is being checked
+ verify_key (VerifyKey): the key to verify the device with
+ signed_device (dict): the signed device data
+ stored_device (dict): our previous copy of the device
+ """
+
+ key_id = "%s:%s" % (verify_key.alg, verify_key.version)
+
+ # make sure the device is signed
+ if ("signatures" not in signed_device or user_id not in signed_device["signatures"]
+ or key_id not in signed_device["signatures"][user_id]):
+ logger.error("upload signature: user not found in signatures")
+ raise SynapseError(
+ 400,
+ "Invalid signature",
+ Codes.INVALID_SIGNATURE
+ )
+
+ signature = signed_device["signatures"][user_id][key_id]
+
+ # make sure that the device submitted matches what we have stored
+ del signed_device["signatures"]
+ if "unsigned" in signed_device:
+ del signed_device["unsigned"]
+ if "signatures" in stored_device:
+ del stored_device["signatures"]
+ if "unsigned" in stored_device:
+ del stored_device["unsigned"]
+ if signed_device != stored_device:
+ logger.error(
+ "upload signatures: key does not match %s vs %s",
+ signed_device, stored_device
+ )
+ raise SynapseError(
+ 400,
+ "Key does not match",
+ "M_MISMATCHED_KEY"
+ )
+
+ # check the signature
+ signed_device["signatures"] = {
+ user_id: {
+ key_id: signature
+ }
+ }
+
+ try:
+ verify_signed_json(signed_device, user_id, verify_key)
+ except SignatureVerifyException:
+ logger.error("invalid signature on key")
+ raise SynapseError(
+ 400,
+ "Invalid signature",
+ Codes.INVALID_SIGNATURE
+ )
+
+
def _exception_to_failure(e):
if isinstance(e, CodeMessageException):
return {"status": e.code, "message": str(e)}
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