MollySocket

MollySocket allows getting signal notifications via UnifiedPush. It works like a linked device, which doesn't have an encryption key, connected to the Signal server. Everytime it receives an encrypted event, it notifies your mobile via UnifiedPush.

Overview

---
title: Message flow
---
graph TD
    
    MS[fa:fa-tablets MollySocket]
    S[fa:fa-comment Signal Server]
    P[fa:fa-server Push server]
    subgraph "fa:fa-mobile Android"
        D[fa:fa-tower-broadcast Distributor App]
        MA[fa:fa-tablets Molly Android]
    end
    MS -- 1. Persistent connection --> S
    MS -- 2. 'Notifications present' --> P
    P -- 3. 'Notications present for Molly' --> D
    D -- 4. 'Check Signal servers' --> MA
    MA -- 5. 'Got messages?' --> S
    S -- 6. Messages --> MA

Setup

1. You need the right flavor of Molly to use UnifiedPush: https://github.com/mollyim/mollyim-android-unifiedpush.
2. You can install MollySocket via:
   1. Docker/Podman: docker pull ghcr.io/mollyim/mollysocket:latest
   2. Crates.io: cargo install mollysocket (see INSTALL.md for the setup)
   3. Direct download: https://github.com/mollyim/mollysocket/releases (see INSTALL.md for the setup)
3. A distributor app (easiest is ntfy)

You can optionally install your own push server like ntfy or NextPush. For beginners, you can use a free service like ntfy.sh (do consider donating if you have the means).

Web Server

MollySocket exposes a web server so that Molly can send the information it needs to operate. You must configure TLS with a reverse proxy in front of MollySocket. Molly can only connect to the server over HTTPS.

It is possible to use MollySocket without the web server, but you will have to manually register the information MollySocket needs: see the Air Gapped mode on Android settings.

Configuration

The configuration file uses the TOML format. Below is an overview of configuration options. You can configure each parameter using either the conf file, the environment variable or the cli option (if available).

* Takes the precedence

allowed_endpoints

These are the UnifiedPush endpoints that MollySocket may use to push notifications with.

⚠️ If you self-host your push server, add your push server to the allowed_endpoints. ⚠️

That's because, for security reasons, endpoints on your local network must be allowed explicitly. You just have to set the scheme (https), the domain and the port if required. For instance allowed_endpoints=['https://push.mydomain.tld']

allowed_uuids

You can allow registration for all accounts by setting allowed_uuids to ['*']. Else set your account ids in the array: ['account_id1','account_id2'].

The account IDs are showing in the Molly application under Settings > Notifications > UnifiedPush. You need to activate UnifiedPush first before your account ID is shown.

Troubleshoot

• On the Android app, the status states MollySocket server not found

You haven't entered the right url.

This must be the one where MollySocket is reachable. To test it, open the link you have entered in a browser: you should see a json containing the version of MollySocket. For instance {"mollysocket":{"version":"1.2.0"}}.

If you can access the web server, make sure it is accessible over HTTPS. Molly can't connect to the server over HTTP.

• On the Android app, the status states The account ID is refused by the server

You have restricted the allowed account ID who can use your MollySocket server.

Add your account ID[1] to allowed_uuids to allow your account, or add a wildcard ["*"] to allow all the accounts to use your server. See Configuration to configure your server correctly.

[1] Your account ID can be copied on the Android app, under the UnifiedPush settings

• On the Android app, the status states The endpoint is forbidden by the server

You have restricted the allowed UnifiedPush endpoints, or you are using a self-hosted server you haven't whitelisted.

Add your server to the allowed_endpoints: ["https://push.mydomain.tld"]. This is NOT your MollySocket URL but the one from your push provider. See Configuration to configure your server correctly.

• I use the Air-gapped mode and I don't receive notifications.

If you use air-gapped mode, then Molly (android) can't test the setup and it assumes you have correctly setup everything. You should double check that the account ID is accepted by your mollysocket server and the endpoint is allowed by your mollysocket server (check the output logs).

• The status is "OK" or "OK: Air Gapped" but I still don't get notifications

If you are using Molly version >= 7.1.3-1.up1 and MollySocket version >= 1.3.0, you can run this command:

$ mollysocket connection ping c8d44128-5c99-4810-a7d3-71c079891c27 # Replace this UUID with your account Id

If you receive a test notification (image bellow), then you should check that Molly and your distributor have unrestricted battery usage. You should check if you have additional configuration for your device regarding battery management: https://dontkillmyapp.com/.

If you don't receive a test notification, then your MollySocket server can't reach your push server or your phone don't have network access.

About security

Relative to Signal security

MollySocket never has any encryption key

MollySocket receives the credentials for a linked device and does not receive any encryption key. Which means:

• Someone with access to MollySocket database can't change the identity key, to impersonate users. See setKeys.
• Someone with access to MollySocket database may be able to use the credentials of linked devices to spam the Signal server and hit the rate limits. I haven't checked if this would temporarily block the account or just the linked device. (Availability risk)
• Someone with access to MollySocket database may be able to change some account field in a destructive way. For instance changing the account Name to something random. The cleartext will be random since these field are encrypted and require encryption keys to be properly encrypted.

License

AGPLv3: see LICENSE.txt.

Disclaimer

This project is NOT sponsored by or affiliated to Signal Messenger or Signal Foundation.

The software is produced independently of Signal and carries no guarantee about quality, security or anything else. Use at your own risk.