From 7dcbc33a1be04c46b930699c03c15bc759f4b22c Mon Sep 17 00:00:00 2001 From: Patrick Cloke Date: Tue, 3 Mar 2020 07:12:45 -0500 Subject: Validate the alt_aliases property of canonical alias events (#6971) --- synapse/api/errors.py | 1 + synapse/handlers/directory.py | 14 ++++++------- synapse/handlers/message.py | 47 ++++++++++++++++++++++++++++++++++++++++--- synapse/types.py | 15 +++++++++----- 4 files changed, 62 insertions(+), 15 deletions(-) (limited to 'synapse') diff --git a/synapse/api/errors.py b/synapse/api/errors.py index 0c20601600..616942b057 100644 --- a/synapse/api/errors.py +++ b/synapse/api/errors.py @@ -66,6 +66,7 @@ class Codes(object): EXPIRED_ACCOUNT = "ORG_MATRIX_EXPIRED_ACCOUNT" INVALID_SIGNATURE = "M_INVALID_SIGNATURE" USER_DEACTIVATED = "M_USER_DEACTIVATED" + BAD_ALIAS = "M_BAD_ALIAS" class CodeMessageException(RuntimeError): diff --git a/synapse/handlers/directory.py b/synapse/handlers/directory.py index 0b23ca919a..61eb49059b 100644 --- a/synapse/handlers/directory.py +++ b/synapse/handlers/directory.py @@ -13,8 +13,6 @@ # See the License for the specific language governing permissions and # limitations under the License. - -import collections import logging import string from typing import List @@ -307,15 +305,17 @@ class DirectoryHandler(BaseHandler): send_update = True content.pop("alias", "") - # Filter alt_aliases for the removed alias. - alt_aliases = content.pop("alt_aliases", None) - # If the aliases are not a list (or not found) do not attempt to modify - # the list. - if isinstance(alt_aliases, collections.Sequence): + # Filter the alt_aliases property for the removed alias. Note that the + # value is not modified if alt_aliases is of an unexpected form. + alt_aliases = content.get("alt_aliases") + if isinstance(alt_aliases, (list, tuple)) and alias_str in alt_aliases: send_update = True alt_aliases = [alias for alias in alt_aliases if alias != alias_str] + if alt_aliases: content["alt_aliases"] = alt_aliases + else: + del content["alt_aliases"] if send_update: yield self.event_creation_handler.create_and_send_nonmember_event( diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py index a0103addd3..0c84c6cec4 100644 --- a/synapse/handlers/message.py +++ b/synapse/handlers/message.py @@ -888,19 +888,60 @@ class EventCreationHandler(object): yield self.base_handler.maybe_kick_guest_users(event, context) if event.type == EventTypes.CanonicalAlias: - # Check the alias is acually valid (at this time at least) + # Validate a newly added alias or newly added alt_aliases. + + original_alias = None + original_alt_aliases = set() + + original_event_id = event.unsigned.get("replaces_state") + if original_event_id: + original_event = yield self.store.get_event(original_event_id) + + if original_event: + original_alias = original_event.content.get("alias", None) + original_alt_aliases = original_event.content.get("alt_aliases", []) + + # Check the alias is currently valid (if it has changed). room_alias_str = event.content.get("alias", None) - if room_alias_str: + directory_handler = self.hs.get_handlers().directory_handler + if room_alias_str and room_alias_str != original_alias: room_alias = RoomAlias.from_string(room_alias_str) - directory_handler = self.hs.get_handlers().directory_handler mapping = yield directory_handler.get_association(room_alias) if mapping["room_id"] != event.room_id: raise SynapseError( 400, "Room alias %s does not point to the room" % (room_alias_str,), + Codes.BAD_ALIAS, ) + # Check that alt_aliases is the proper form. + alt_aliases = event.content.get("alt_aliases", []) + if not isinstance(alt_aliases, (list, tuple)): + raise SynapseError( + 400, "The alt_aliases property must be a list.", Codes.INVALID_PARAM + ) + + # If the old version of alt_aliases is of an unknown form, + # completely replace it. + if not isinstance(original_alt_aliases, (list, tuple)): + original_alt_aliases = [] + + # Check that each alias is currently valid. + new_alt_aliases = set(alt_aliases) - set(original_alt_aliases) + if new_alt_aliases: + for alias_str in new_alt_aliases: + room_alias = RoomAlias.from_string(alias_str) + mapping = yield directory_handler.get_association(room_alias) + + if mapping["room_id"] != event.room_id: + raise SynapseError( + 400, + "Room alias %s does not point to the room" + % (room_alias_str,), + Codes.BAD_ALIAS, + ) + federation_handler = self.hs.get_handlers().federation_handler if event.type == EventTypes.Member: diff --git a/synapse/types.py b/synapse/types.py index f3cd465735..acf60baddc 100644 --- a/synapse/types.py +++ b/synapse/types.py @@ -23,7 +23,7 @@ import attr from signedjson.key import decode_verify_key_bytes from unpaddedbase64 import decode_base64 -from synapse.api.errors import SynapseError +from synapse.api.errors import Codes, SynapseError # define a version of typing.Collection that works on python 3.5 if sys.version_info[:3] >= (3, 6, 0): @@ -166,11 +166,13 @@ class DomainSpecificString(namedtuple("DomainSpecificString", ("localpart", "dom return self @classmethod - def from_string(cls, s): + def from_string(cls, s: str): """Parse the string given by 's' into a structure object.""" if len(s) < 1 or s[0:1] != cls.SIGIL: raise SynapseError( - 400, "Expected %s string to start with '%s'" % (cls.__name__, cls.SIGIL) + 400, + "Expected %s string to start with '%s'" % (cls.__name__, cls.SIGIL), + Codes.INVALID_PARAM, ) parts = s[1:].split(":", 1) @@ -179,6 +181,7 @@ class DomainSpecificString(namedtuple("DomainSpecificString", ("localpart", "dom 400, "Expected %s of the form '%slocalname:domain'" % (cls.__name__, cls.SIGIL), + Codes.INVALID_PARAM, ) domain = parts[1] @@ -235,11 +238,13 @@ class GroupID(DomainSpecificString): def from_string(cls, s): group_id = super(GroupID, cls).from_string(s) if not group_id.localpart: - raise SynapseError(400, "Group ID cannot be empty") + raise SynapseError(400, "Group ID cannot be empty", Codes.INVALID_PARAM) if contains_invalid_mxid_characters(group_id.localpart): raise SynapseError( - 400, "Group ID can only contain characters a-z, 0-9, or '=_-./'" + 400, + "Group ID can only contain characters a-z, 0-9, or '=_-./'", + Codes.INVALID_PARAM, ) return group_id -- cgit 1.4.1