diff options
Diffstat (limited to 'synapse/handlers')
| -rw-r--r-- | synapse/handlers/e2e_keys.py | 266 |
1 files changed, 159 insertions, 107 deletions
diff --git a/synapse/handlers/e2e_keys.py b/synapse/handlers/e2e_keys.py index cca361b15b..352c8ee93b 100644 --- a/synapse/handlers/e2e_keys.py +++ b/synapse/handlers/e2e_keys.py @@ -19,6 +19,8 @@ import logging from six import iteritems +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 @@ -26,7 +28,7 @@ from unpaddedbase64 import decode_base64 from twisted.internet import defer -from synapse.api.errors import CodeMessageException, Codes, SynapseError +from synapse.api.errors import CodeMessageException, Codes, NotFoundError, SynapseError from synapse.logging.context import make_deferred_yieldable, run_in_background from synapse.logging.opentracing import log_kv, set_tag, tag_args, trace from synapse.types import ( @@ -617,12 +619,18 @@ class E2eKeysHandler(object): Args: user_id (string): the user uploading the signatures signatures (dict[string, dict[string, dict]]): map of users to - devices to signed keys + devices to signed keys. This is the submission from the user; an + exception will be raised if it is malformed. + Returns: + dict: response to be sent back to the client. The response will have + a "failures" key, which will be a dict mapping users to devices + to errors for the signatures that failed. + Raises: + SynapseError: if the signatures dict is not valid. """ failures = {} - # signatures to be stored. Each item will be a tuple of - # (signing_key_id, target_user_id, target_device_id, signature) + # signatures to be stored. Each item will be a SignatureListItem signature_list = [] # split between checking signatures for own user and signatures for @@ -646,10 +654,10 @@ class E2eKeysHandler(object): logger.debug("upload signature failures: %r", failures) yield self.store.store_e2e_cross_signing_signatures(user_id, signature_list) - self_device_ids = [device_id for (_, _, device_id, _) in self_signature_list] + self_device_ids = [item.target_device_id for item in self_signature_list] if self_device_ids: yield self.device_handler.notify_device_update(user_id, self_device_ids) - signed_users = [user_id for (_, user_id, _, _) in other_signature_list] + signed_users = [item.target_user_id for item in other_signature_list] if signed_users: yield self.device_handler.notify_user_signature_update( user_id, signed_users @@ -661,48 +669,58 @@ class E2eKeysHandler(object): def _process_self_signatures(self, user_id, signatures): """Process uploaded signatures of the user's own keys. + Signatures of the user's own keys from this API come in two forms: + - signatures of the user's devices by the user's self-signing key, + - signatures of the user's master key by the user's devices. + Args: user_id (string): the user uploading the keys signatures (dict[string, dict]): map of devices to signed keys Returns: - (list[(string, string, string, string)], dict[string, dict[string, dict]]): - a list of signatures to upload, in the form (signing_key_id, target_user_id, - target_device_id, signature), and a map of users to devices to failure + (list[SignatureListItem], dict[string, dict[string, dict]]): + a list of signatures to upload, and a map of users to devices to failure reasons + + Raises: + SynapseError: if the input is malformed """ signature_list = [] failures = {} if not signatures: return signature_list, failures + if not isinstance(signatures, dict): + raise SynapseError(400, "Invalid parameter", Codes.INVALID_PARAM) + try: # get our self-signing key to verify the signatures - self_signing_key, self_signing_key_id, self_signing_verify_key = yield self._get_e2e_cross_signing_verify_key( + _, self_signing_key_id, self_signing_verify_key = yield self._get_e2e_cross_signing_verify_key( user_id, "self_signing" ) # get our master key, since it may be signed - master_key, master_key_id, master_verify_key = yield self._get_e2e_cross_signing_verify_key( + master_key, _, master_verify_key = yield self._get_e2e_cross_signing_verify_key( user_id, "master" ) # fetch our stored devices. This is used to 1. verify - # signatures on the master key, and 2. to can compare with what + # signatures on the master key, and 2. to compare with what # was sent if the device was signed devices = yield self.store.get_e2e_device_keys([(user_id, None)]) if user_id not in devices: - raise SynapseError(404, "No device keys found", Codes.NOT_FOUND) + raise NotFoundError("No device keys found") devices = devices[user_id] except SynapseError as e: - failures[user_id] = { - device: _exception_to_failure(e) for device in signatures.keys() - } + failure = _exception_to_failure(e) + failures[user_id] = {device: failure for device in signatures.keys()} return signature_list, failures for device_id, device in signatures.items(): + if not isinstance(device, dict): + raise SynapseError(400, "Invalid parameter", Codes.INVALID_PARAM) try: if "signatures" not in device or user_id not in device["signatures"]: # no signature was sent @@ -711,45 +729,9 @@ class E2eKeysHandler(object): ) if device_id == master_verify_key.version: - # we have master key signed by devices: for each - # device that signed, check the signature. Since - # the "failures" property in the response only has - # granularity up to the signed device, either all - # of the signatures on the master key succeed, or - # all fail. So loop over the signatures and add - # them to a separate signature list. If everything - # works out, then add them all to the main - # signature list. (In practice, we're likely to - # only have only one signature anyways.) - master_key_signature_list = [] - sigs = device["signatures"] - for signing_key_id, signature in sigs[user_id].items(): - alg, signing_device_id = signing_key_id.split(":", 1) - if ( - signing_device_id not in devices - or signing_key_id - not in devices[signing_device_id]["keys"]["keys"] - ): - # signed by an unknown device, or the - # device does not have the key - raise SynapseError( - 400, "Invalid signature", Codes.INVALID_SIGNATURE - ) - - # get the key and check the signature - pubkey = devices[signing_device_id]["keys"]["keys"][ - signing_key_id - ] - verify_key = decode_verify_key_bytes( - signing_key_id, decode_base64(pubkey) - ) - _check_device_signature(user_id, verify_key, device, master_key) - device["signatures"] = sigs - - master_key_signature_list.append( - (signing_key_id, user_id, device_id, signature) - ) - + master_key_signature_list = self._check_master_key_signature( + user_id, device_id, device, master_key, devices + ) signature_list.extend(master_key_signature_list) continue @@ -765,7 +747,7 @@ class E2eKeysHandler(object): try: stored_device = devices[device_id]["keys"] except KeyError: - raise SynapseError(404, "Unknown device", Codes.NOT_FOUND) + raise NotFoundError("Unknown device") if self_signing_key_id in stored_device.get("signatures", {}).get( user_id, {} ): @@ -779,26 +761,75 @@ class E2eKeysHandler(object): signature = device["signatures"][user_id][self_signing_key_id] signature_list.append( - (self_signing_key_id, user_id, device_id, signature) + SignatureListItem( + self_signing_key_id, user_id, device_id, signature + ) ) except SynapseError as e: failures.setdefault(user_id, {})[device_id] = _exception_to_failure(e) return signature_list, failures + def _check_master_key_signature( + self, user_id, master_key_id, signed_master_key, stored_master_key, devices + ): + """Check signatures of the user's master key made by their devices. + + Args: + user_id (string): the user uploading the keys + signatures (dict[string, dict]): map of users to devices to signed keys + + Returns: + (list[SignatureListItem], dict[string, dict[string, dict]]): + a list of signatures to upload, and a map of users to devices to failure + reasons + + Raises: + SynapseError: if the input is malformed + """ + # for each device that signed the master key, check the signature. + master_key_signature_list = [] + sigs = signed_master_key["signatures"] + for signing_key_id, signature in sigs[user_id].items(): + _, signing_device_id = signing_key_id.split(":", 1) + if ( + signing_device_id not in devices + or signing_key_id not in devices[signing_device_id]["keys"]["keys"] + ): + # signed by an unknown device, or the + # device does not have the key + raise SynapseError(400, "Invalid signature", Codes.INVALID_SIGNATURE) + + # get the key and check the signature + pubkey = devices[signing_device_id]["keys"]["keys"][signing_key_id] + verify_key = decode_verify_key_bytes(signing_key_id, decode_base64(pubkey)) + _check_device_signature( + user_id, verify_key, signed_master_key, stored_master_key + ) + + master_key_signature_list.append( + SignatureListItem(signing_key_id, user_id, master_key_id, signature) + ) + + return master_key_signature_list + @defer.inlineCallbacks def _process_other_signatures(self, user_id, signatures): - """Process uploaded signatures of other users' keys. + """Process uploaded signatures of other users' keys. These will be the + target user's master keys, signed by the uploading user's user-signing + key. Args: user_id (string): the user uploading the keys signatures (dict[string, dict]): map of users to devices to signed keys Returns: - (list[(string, string, string, string)], dict[string, dict[string, dict]]): - a list of signatures to upload, in the form (signing_key_id, target_user_id, - target_device_id, signature), and a map of users to devices to failure + (list[SignatureListItem], dict[string, dict[string, dict]]): + a list of signatures to upload, and a map of users to devices to failure reasons + + Raises: + SynapseError: if the input is malformed """ signature_list = [] failures = {} @@ -816,70 +847,89 @@ class E2eKeysHandler(object): failures[user] = {device_id: failure for device_id in devicemap.keys()} return signature_list, failures - for user, devicemap in signatures.items(): + for target_user, devicemap in signatures.items(): + if not isinstance(devicemap, dict): + raise SynapseError(400, "Invalid parameter", Codes.INVALID_PARAM) + for device in devicemap.values(): + if not isinstance(device, dict): + raise SynapseError(400, "Invalid parameter", Codes.INVALID_PARAM) device_id = None try: - # get the user's master key, to make sure it matches + # get the target user's master key, to make sure it matches # what was sent - stored_key, stored_key_id, _ = yield self._get_e2e_cross_signing_verify_key( - user, "master", user_id + master_key, master_key_id, _ = yield self._get_e2e_cross_signing_verify_key( + target_user, "master", user_id ) - # make sure that the user's master key is the one that + # make sure that the target user's master key is the one that # was signed (and no others) - device_id = stored_key_id.split(":", 1)[1] + device_id = master_key_id.split(":", 1)[1] if device_id not in devicemap: - logger.error( + logger.debug( "upload signature: could not find signature for device %s", device_id, ) # set device to None so that the failure gets # marked on all the signatures device_id = None - raise SynapseError(404, "Unknown device", Codes.NOT_FOUND) + raise NotFoundError("Unknown device") key = devicemap[device_id] other_devices = [k for k in devicemap.keys() if k != device_id] if other_devices: # other devices were signed -- mark those as failures - logger.error("upload signature: too many devices specified") - failure = _exception_to_failure( - SynapseError(404, "Unknown device", Codes.NOT_FOUND) - ) - failures[user] = {device: failure for device in other_devices} + logger.debug("upload signature: too many devices specified") + failure = _exception_to_failure(NotFoundError("Unknown device")) + failures[target_user] = { + device: failure for device in other_devices + } - if user_signing_key_id in stored_key.get("signatures", {}).get( + if user_signing_key_id in master_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 + user_id, user_signing_verify_key, key, master_key ) signature = key["signatures"][user_id][user_signing_key_id] - signature_list.append((user_signing_key_id, user, device_id, signature)) + signature_list.append( + SignatureListItem( + user_signing_key_id, target_user, device_id, signature + ) + ) except SynapseError as e: failure = _exception_to_failure(e) if device_id is None: - failures[user] = { + failures[target_user] = { device_id: failure for device_id in devicemap.keys() } else: - failures.setdefault(user, {})[device_id] = failure + failures.setdefault(target_user, {})[device_id] = failure 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. + + 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. + This affects what signatures are fetched. + + Returns: + dict, str, VerifyKey: the raw key data, the key ID, and the + signedjson verify key + """ key = yield self.store.get_e2e_cross_signing_key( user_id, key_type, from_user_id ) if key is None: logger.error("no %s key found for %s", key_type, user_id) - raise SynapseError( - 404, "No %s key found for %s" % (key_type, user_id), Codes.NOT_FOUND - ) + raise NotFoundError("No %s key found for %s" % (key_type, user_id)) key_id, verify_key = get_verify_key_from_cross_signing_key(key) return key, key_id, verify_key @@ -912,36 +962,30 @@ 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. + """Check that a signature on a device or cross-signing key is correct and + matches the copy of the device/key that we have stored. 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) + signed_device (dict): the uploaded signed device data + stored_device (dict): our previously stored copy of the device - # 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) + Raises: + SynapseError: if the signature was invalid or the sent device is not the + same as the stored device - signature = signed_device["signatures"][user_id][key_id] + """ # make sure that the device submitted matches what we have stored - del signed_device["signatures"] - # use pop to avoid exception if key doesn't exist - signed_device.pop("unsigned", None) - stored_device.pop("signatures", None) - stored_device.pop("unsigned", None) - if signed_device != stored_device: + stripped_signed_device = { + k: v for k, v in signed_device.items() if k not in ["signatures", "unsigned"] + } + stripped_stored_device = { + k: v for k, v in stored_device.items() if k not in ["signatures", "unsigned"] + } + if stripped_signed_device != stripped_stored_device: logger.error( "upload signatures: key does not match %s vs %s", signed_device, @@ -949,9 +993,6 @@ def _check_device_signature(user_id, verify_key, signed_device, stored_device): ) raise SynapseError(400, "Key does not match") - # check the signature - signed_device["signatures"] = {user_id: {key_id: signature}} - try: verify_signed_json(signed_device, user_id, verify_key) except SignatureVerifyException: @@ -990,3 +1031,14 @@ def _one_time_keys_match(old_key_json, new_key): new_key_copy.pop("signatures", None) return old_key == new_key_copy + + +@attr.s +class SignatureListItem: + """An item in the signature list as used by upload_signatures_for_device_keys. + """ + + signing_key_id = attr.ib() + target_user_id = attr.ib() + target_device_id = attr.ib() + signature = attr.ib() |