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mjolnir

A moderation tool for Matrix. Visit #mjolnir:matrix.org for more information.

Features

As an all-in-one moderation tool, it can protect your server from malicious invites, spam messages, and whatever else you don't want. In addition to server-level protection, Mjolnir is great for communities wanting to protect their rooms without having to use their personal accounts for moderation.

The bot by default includes support for bans, redactions, anti-spam, server ACLs, room directory changes, room alias transfers, account deactivation, room shutdown, and more.

A Synapse module is also available to apply the same rulesets the bot uses across an entire homeserver.

Setting up

See the setup documentation for first-time setup documentation.

See the configuration sample with documentation for detailed information about Mjolnir's configuration.

See the synapse module documentation for information on how to setup Mjolnir's accompanying Synapse Module.

Quickstart guide

After your bot is up and running, you'll want to run a couple commands to get everything set up:

  1. !mjolnir list create COC code-of-conduct-ban-list - This will create a new ban list with the shortcode COC and an alias of #code-of-conduct-ban-list:example.org. You will be invited to the room it creates automatically where you can change settings such as the visibility of the room.
  2. !mjolnir default COC - This sets the default ban list to the list we just created to help with the ban commands later on.
  3. Review the Moderator's Guide.
  4. Review !mjolnir help to see what else the bot can do.

Enabling readable abuse reports

Since version 1.2, Mjölnir offers the ability to replace the Matrix endpoint used to report abuse and display it into a room, instead of requiring you to request this data from an admin API.

This requires two configuration steps:

  1. In your Mjölnir configuration file, typically /etc/mjolnir/config/production.yaml, copy and paste the web section from default.yaml, if you don't have it yet (it appears with version 1.20) and set enabled: true for both web and abuseReporting.
  2. Setup a reverse proxy that will redirect requests from ^/_matrix/client/(r0|v3)/rooms/([^/]*)/report/(.*)$ to http://host:port/api/1/report/$2/$3, where host is the host where you run Mjölnir, and port is the port you configured in production.yaml. For an example nginx configuration, see test/nginx.conf. It's the confirmation we use during runtime testing.

Security note

This mechanism can extract some information from unencrypted rooms. We have taken precautions to ensure that this cannot be abused: the only case in which this feature will publish information from room foo is:

  1. If it is used by a member of room foo; AND
  2. If said member did witness the event; AND
  3. If the event was unencrypted; AND
  4. If the event was not redacted/removed/...

Essentially, this is a more restricted variant of the Admin APIs available on homeservers.

However, if you are uncomfortable with this, please do not activate this feature. Also, you should probably setup your production.yaml to ensure that the web server can only receive requests from your reverse proxy (e.g. localhost).

Development

TODO. It's a TypeScript project with a linter.

Development and testing with mx-tester

WARNING: mx-tester is currently work in progress, but it can still save you some time and is better than struggling with nothing.

If you have docker installed you can quickly get setup with a development environment by using mx-tester.

To use mx-tester you will need to have rust installed. You can do that at rustup or here, you should probably also check your distro's documentation first to see if they have specific instructions for installing rust.

Once rust is installed you can install mx-tester like so.

$ cargo install mx-tester

Once you have mx-tester installed you we will want to build a synapse image with synapse_antispam from the Mjolnir project root.

$ mx-tester build

Then we can start a container that uses that image and the config in mx-tester.yml.

$ mx-tester up

Once you have called mx-tester up you can run the integration tests.

$ yarn test:integration

After calling mx-tester up, if we want to play with mojlnir locally we can run the following and then point a matrix client to http://localhost:9999. You should then be able to join the management room at #moderators:localhost:9999.

yarn test:manual

Once we are finished developing we can stop the synapse container.

mx-tester down

Running integration tests

The integration tests can be run with yarn test:integration. The config that the tests use is in config/harness.yaml and by default this is configured to work with the server specified in mx-tester.yml, but you can configure it however you like to run against your own setup.