You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
89 lines
4.0 KiB
Plaintext
89 lines
4.0 KiB
Plaintext
---
|
|
title: Server ACL
|
|
description: |-
|
|
An event to indicate which servers are permitted to participate in the
|
|
room. Server ACLs may allow or deny groups of hosts. All servers participating
|
|
in the room, including those that are denied, are expected to uphold the
|
|
server ACL. Servers that do not uphold the ACLs MUST be added to the denied hosts
|
|
list in order for the ACLs to remain effective.
|
|
|
|
The ``allow`` and ``deny`` lists are lists of globs supporting ``?`` and ``*``
|
|
as wildcards. When comparing against the server ACLs, the suspect server's port
|
|
number must not be considered. Therefore ``evil.com``, ``evil.com:8448``, and
|
|
``evil.com:1234`` would all match rules that apply to ``evil.com``, for example.
|
|
|
|
The ACLs are applied to servers when they make requests, and are applied in
|
|
the following order:
|
|
|
|
1. If there is no ``m.room.server_acl`` event in the room state, allow.
|
|
#. If the server name is an IP address (v4 or v6) literal, and ``allow_ip_literals``
|
|
is present and ``false``, deny.
|
|
#. If the server name matches an entry in the ``deny`` list, deny.
|
|
#. If the server name matches an entry in the ``allow`` list, allow.
|
|
#. Otherwise, deny.
|
|
|
|
.. Note::
|
|
Server ACLs do not restrict the events relative to the room DAG via authorisation
|
|
rules, but instead act purely at the network layer to determine which servers are
|
|
allowed to connect and interact with a given room.
|
|
|
|
.. WARNING::
|
|
Failing to provide an ``allow`` rule of some kind will prevent **all**
|
|
servers from participating in the room, including the sender. This renders
|
|
the room unusable. A common allow rule is ``[ "*" ]`` which would still
|
|
permit the use of the ``deny`` list without losing the room.
|
|
|
|
.. WARNING::
|
|
All compliant servers must implement server ACLs. However, legacy or noncompliant
|
|
servers exist which do not uphold ACLs, and these MUST be manually appended to
|
|
the denied hosts list when setting an ACL to prevent them from leaking events from
|
|
banned servers into a room. Currently, the only way to determine noncompliant hosts is
|
|
to check the ``prev_events`` of leaked events, therefore detecting servers which
|
|
are not upholding the ACLs. Server versions can also be used to try to detect hosts that
|
|
will not uphold the ACLs, although this is not comprehensive. Server ACLs were added
|
|
in Synapse v0.32.0, although other server implementations and versions exist in the world.
|
|
allOf:
|
|
- $ref: core-event-schema/state_event.yaml
|
|
type: object
|
|
properties:
|
|
content:
|
|
properties:
|
|
allow_ip_literals:
|
|
type: boolean
|
|
description: |-
|
|
True to allow server names that are IP address literals. False to
|
|
deny. Defaults to true if missing or otherwise not a boolean.
|
|
|
|
This is strongly recommended to be set to ``false`` as servers running
|
|
with IP literal names are strongly discouraged in order to require
|
|
legitimate homeservers to be backed by a valid registered domain name.
|
|
allow:
|
|
type: array
|
|
description: |-
|
|
The server names to allow in the room, excluding any port information.
|
|
Wildcards may be used to cover a wider range of hosts, where ``*``
|
|
matches zero or more characters and ``?`` matches exactly one character.
|
|
|
|
**This defaults to an empty list when not provided, effectively disallowing
|
|
every server.**
|
|
items:
|
|
type: string
|
|
deny:
|
|
type: array
|
|
description: |-
|
|
The server names to disallow in the room, excluding any port information.
|
|
Wildcards may be used to cover a wider range of hosts, where ``*``
|
|
matches zero or more characters and ``?`` matches exactly one character.
|
|
|
|
This defaults to an empty list when not provided.
|
|
items:
|
|
type: string
|
|
type: object
|
|
state_key:
|
|
description: A zero-length string.
|
|
pattern: '^$'
|
|
type: string
|
|
type:
|
|
enum: ['m.room.server_acl']
|
|
type: string
|