diff options
Diffstat (limited to 'synapse/handlers/e2e_keys.py')
| -rw-r--r-- | synapse/handlers/e2e_keys.py | 232 |
1 files changed, 150 insertions, 82 deletions
diff --git a/synapse/handlers/e2e_keys.py b/synapse/handlers/e2e_keys.py index 9747b517ff..1148803c1e 100644 --- a/synapse/handlers/e2e_keys.py +++ b/synapse/handlers/e2e_keys.py @@ -20,7 +20,9 @@ import logging from six import iteritems from canonicaljson import encode_canonical_json, json +from signedjson.key import decode_verify_key_bytes from signedjson.sign import SignatureVerifyException, verify_signed_json +from unpaddedbase64 import decode_base64 from twisted.internet import defer @@ -619,8 +621,11 @@ class E2eKeysHandler(object): """ failures = {} - signature_list = [] # signatures to be stored - self_device_ids = [] # what devices have been updated, for notifying + # signatures to be stored. Each item will be a tuple of + # (signing_key_id, target_user_id, target_device_id, signature) + signature_list = [] + # what devices have been updated, for notifying + self_device_ids = [] # split between checking signatures for own user and signatures for # other users, since we verify them with different keys @@ -630,46 +635,107 @@ class E2eKeysHandler(object): 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, self_signing_key_id, self_signing_verify_key \ + = yield self._get_e2e_cross_signing_verify_key( + user_id, "self_signing" ) - self_signing_key_id, self_signing_verify_key \ - = get_verify_key_from_cross_signing_key(self_signing_key) + # 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( + user_id, "master" + ) - # 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) + # fetch our stored devices. This is used to 1. verify + # signatures on the master key, and 2. to can 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 key found", - Codes.NOT_FOUND + 404, "No device keys 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]): + user_id not in device["signatures"]): + # no signature was sent + raise SynapseError( + 400, "Invalid signature", Codes.INVALID_SIGNATURE + ) + + 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 = [] + for signing_key_id, signature in device["signatures"][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 + ) + + sigs = device["signatures"] + del device["signatures"] + # use pop to avoid exception if key doesn't exist + device.pop("unsigned", None) + master_key.pop("signature", None) + master_key.pop("unsigned", None) + + if master_key != device: + raise SynapseError( + 400, "Key does not match" + ) + + # 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) + ) + device["signatures"] = sigs + try: + verify_signed_json(device, user_id, verify_key) + except SignatureVerifyException: + raise SynapseError( + 400, "Invalid signature", Codes.INVALID_SIGNATURE + ) + + master_key_signature_list.append( + (signing_key_id, user_id, device_id, signature) + ) + + signature_list.extend(master_key_signature_list) + continue + + # at this point, we have a device that should be signed + # by the self-signing key + if self_signing_key_id not in device["signatures"][user_id]: # no signature was sent raise SynapseError( - 400, - "Invalid signature", - Codes.INVALID_SIGNATURE + 400, "Invalid signature", Codes.INVALID_SIGNATURE ) - stored_device = devices[device_id]["keys"] + stored_device = None + try: + stored_device = devices[device_id]["keys"] + except KeyError: + raise SynapseError( + 404, "Unknown device", Codes.NOT_FOUND + ) if self_signing_key_id in stored_device.get("signatures", {}) \ .get(user_id, {}): # we already have a signature on this device, so we @@ -698,69 +764,50 @@ class E2eKeysHandler(object): # 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) + try: + # get our user-signing key to verify the signatures + user_signing_key, user_signing_key_id, user_signing_verify_key \ + = yield self._get_e2e_cross_signing_verify_key( + user_id, "user_signing" + ) 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 + stored_key, stored_key_id, _ \ + = yield self._get_e2e_cross_signing_verify_key( + user, "master", user_id ) # 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] + device_id = stored_key_id.split(":", 1)[1] if device_id not in devicemap: + # set device to None so that the failure gets + # marked on all the signatures + device_id = None logger.error( "upload signature: wrong device: %s vs %s", device, devicemap ) raise SynapseError( - 404, - "Unknown device", - Codes.NOT_FOUND + 404, "Unknown device", Codes.NOT_FOUND ) - if len(devicemap) > 1: + key = devicemap[device_id] + del devicemap[device_id] + if len(devicemap) > 0: + # 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: _exception_to_failure(SynapseError( - 404, - "Unknown device", - Codes.NOT_FOUND - )) + device: failure 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 @@ -770,25 +817,31 @@ class E2eKeysHandler(object): user_id, user_signing_verify_key, key, stored_key ) - signature = key["signatures"][user_id][user_signing_key_id] - signed_users.append(user) + signature = key["signatures"][user_id][user_signing_key_id] signature_list.append( (user_signing_key_id, user, device_id, signature) ) except SynapseError as e: + failure = _exception_to_failure(e) if device_id is None: failures[user] = { - device_id: _exception_to_failure(e) + device_id: failure for device_id in devicemap.keys() } else: - failures.setdefault(user, {})[device_id] \ - = _exception_to_failure(e) + failures.setdefault(user, {})[device_id] = failure + except SynapseError as e: + failure = _exception_to_failure(e) + for user, devicemap in signature.items(): + failures[user] = { + device_id: failure + for device_id in devicemap.keys() + } # 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) + yield self.store.store_e2e_cross_signing_signatures(user_id, signature_list) if len(self_device_ids): yield self.device_handler.notify_device_update(user_id, self_device_ids) @@ -797,6 +850,22 @@ class E2eKeysHandler(object): defer.returnValue({"failures": failures}) + @defer.inlineCallbacks + def _get_e2e_cross_signing_verify_key(self, user_id, key_type, from_user_id=None): + 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 + ) + key_id, verify_key = get_verify_key_from_cross_signing_key(key) + return key, key_id, 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 checking, and ensures that it is signed, if a signature is required. @@ -851,21 +920,17 @@ def _check_device_signature(user_id, verify_key, signed_device, stored_device): # 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"] + # 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: 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" + 400, "Key does not match", ) # check the signature @@ -887,6 +952,9 @@ def _check_device_signature(user_id, verify_key, signed_device, stored_device): def _exception_to_failure(e): + if isinstance(e, SynapseError): + return {"status": e.code, "errcode": e.errcode, "message": str(e)} + if isinstance(e, CodeMessageException): return {"status": e.code, "message": str(e)} |