Awesome

Mullvad VPN desktop and mobile app

Welcome to the Mullvad VPN client app source code repository. This is the VPN client software for the Mullvad VPN service. For more information about the service, please visit our website, mullvad.net (Also accessible via Tor on our onion service).

This repository contains all the source code for the desktop and mobile versions of the app. For desktop this includes the system service/daemon (mullvad-daemon), a graphical user interface (GUI) and a command line interface (CLI). The Android app uses the same backing system service for the tunnel and security but has a dedicated frontend in android/. iOS consists of a completely standalone implementation that resides in ios/.

Releases

There are built and signed releases for macOS, Windows, Linux and Android available on our website and on Github. The Android app is also available on Google Play and F-Droid and the iOS version on App Store.

You can find our code signing keys as well as instructions for how to cryptographically verify your download on Mullvad's Open Source page.

Platform/OS support

These are the operating systems and their versions that the app officially supports. It might work on many more versions, but we don't test for those and can't guarantee the quality or security.

On Linux we test using the Gnome desktop environment. The app should, and probably does work in other DEs, but we don't regularly test those.

Features

Here is a table containing the features of the app across platforms. This is intended to reflect the current state of the latest code in git, not necessarily any existing release.

* The local network is always accessible on iOS with the current implementation

Security and anonymity

This app is a privacy preserving VPN client. As such it goes to great lengths to stop traffic leaks. And basically all settings default to the more secure/private option. The user has to explicitly allow more loose rules if desired. See the dedicated security document for details on what the app blocks and allows, as well as how it does it.

Checking out the code

This repository contains submodules needed for building the app. However, some of those submodules also have further submodules that are quite large and not needed to build the app. So unless you want the source code for OpenSSL, OpenVPN and a few other projects you should avoid a recursive clone of the repository. Instead clone the repository normally and then get one level of submodules:

git clone https://github.com/mullvad/mullvadvpn-app.git
cd mullvadvpn-app
git submodule update --init

On Android, Linux and macOS you also want to checkout the wireguard-go submodule recursively:

git submodule update --init --recursive --depth=1 wireguard-go-rs

Further details on why this is necessary can be found in the wireguard-go-rs crate.

We sign every commit on the main branch as well as our release tags. If you would like to verify your checkout, you can find our developer keys on Mullvad's Open Source page.

Binaries submodule

This repository has a git submodule at dist-assets/binaries. This submodule contains binaries and build scripts for third party code we need to bundle with the app. Such as OpenVPN, Wintun etc.

This submodule conforms to the same integrity/security standards as this repository. Every merge commit should be signed. And this main repository should only ever point to a signed merge commit of the binaries submodule.

See the binaries submodule's README for more details about that repository.

Building the app

See the build instructions for help building the app on desktop platforms.

For building the Android app, see the instructions for Android.

For building the iOS app, see the instructions for iOS.

Releasing the app

See this for instructions on how to make a new release.

Environment variables used by the service

• TALPID_FIREWALL_DEBUG - Helps debugging the firewall. Does different things depending on platform:

  • Linux: Set to "1" to add packet counters to all firewall rules.
  • macOS: Makes rules log the packets they match to the pflog0 interface.
    • Set to "all" to add logging to all rules.
    • Set to "pass" to add logging to rules allowing packets.
    • Set to "drop" to add logging to rules blocking packets.

• TALPID_FIREWALL_DONT_SET_SRC_VALID_MARK - Set this variable to 1 to stop the daemon from setting the net.ipv4.conf.all.src_valid_mark kernel parameter to 1 on Linux when a tunnel is established. The kernel config parameter is set by default, because otherwise strict reverse path filtering may prevent relay traffic from reaching the daemon. If rp_filter is set to 1 on the interface that will be receiving relay traffic, and src_valid_mark is not set to 1, the daemon will not be able to receive relay traffic.

• TALPID_FIREWALL_DONT_SET_ARP_IGNORE - Set this variable to 1 to stop the daemon from setting the net.ipv4.conf.all.arp_ignore kernel parameter to 2 on Linux when a tunnel is established. The kernel config parameter is set by default, because otherwise an attacker who can send ARP requests to the device running Mullvad can figure out the in-tunnel IP.

• TALPID_DNS_MODULE - Allows changing the method that will be used for DNS configuration. By default this is automatically detected, but you can set it to one of the options below to choose a specific method.

  • Linux

    • "static-file": change the /etc/resolv.conf file directly
    • "resolvconf": use the resolvconf program
    • "systemd": use systemd's resolved service through DBus
    • "network-manager": use NetworkManager service through DBus

  • Windows

    • iphlpapi: use the IP helper API
    • netsh: use the netsh program
    • tcpip: set TCP/IP parameters in the registry

• TALPID_FORCE_USERSPACE_WIREGUARD - Forces the daemon to use the userspace implementation of WireGuard on Linux.

• TALPID_DISABLE_OFFLINE_MONITOR - Forces the daemon to always assume the host is online.

• TALPID_NET_CLS_MOUNT_DIR - On Linux, forces the daemon to mount the net_cls controller in the specified directory if it isn't mounted already.

• MULLVAD_MANAGEMENT_SOCKET_GROUP - On Linux and macOS, this restricts access to the management interface UDS socket to users in the specified group. This means that only users in that group can use the CLI and GUI. By default, everyone has access to the socket.

• MULLVAD_BACKTRACE_ON_FAULT - When enabled, if the daemon encounters a fault (e.g. SIGSEGV), it will log a backtrace to stdout, and to daemon.log. By default, this is disabled in release-builds and enabled in debug-builds. Set variable to 1 or 0 to explicitly enable or disable this feature. Logging the backtrace cause heap allocation. Allocation is not signal safe, but here it runs in the signal handler. This in technically undefined behavior and therefore disabled by default. This usually works, but enable at your own risk.

Development builds only

• MULLVAD_API_HOST - Set the hostname to use in API requests. E.g. api.mullvad.net.

• MULLVAD_API_ADDR - Set the IP address and port to use in API requests. E.g. 10.10.1.2:443.

• MULLVAD_API_DISABLE_TLS - Use plain HTTP for API requests.

• MULLVAD_CONNCHECK_HOST - Set the hostname to use in connection check requests. E.g. am.i.mullvad.net.

Setting environment variables

Windows

Use setx from an elevated shell:

setx TALPID_DISABLE_OFFLINE 1 /m

For the change to take effect, restart the daemon:

sc.exe stop mullvadvpn
sc.exe start mullvadvpn

Linux

Edit the systemd unit file via systemctl edit mullvad-daemon.service:

[Service]
Environment="TALPID_DISABLE_OFFLINE_MONITOR=1"

For the change to take effect, restart the daemon:

sudo systemctl restart mullvad-daemon

macOS

Use plutil:

sudo plutil -replace EnvironmentVariables -json '{"TALPID_DISABLE_OFFLINE_MONITOR": "1"}' /Library/LaunchDaemons/net.mullvad.daemon.plist

For the change to take effect, restart the daemon:

launchctl unload -w /Library/LaunchDaemons/net.mullvad.daemon.plist
launchctl load -w /Library/LaunchDaemons/net.mullvad.daemon.plist

Environment variables used by the desktop frontend

• MULLVAD_PATH - Allows changing the path to the folder with the mullvad-problem-report tool when running in development mode. Defaults to: <repo>/target/debug/.
• MULLVAD_DISABLE_UPDATE_NOTIFICATION - If set to 1, notification will be disabled when an update is available.

Command line tools for Electron app development

• $ npm run develop - develop app with live-reload enabled
• $ npm run lint - lint code
• $ npm run pack:<OS> - prepare app for distribution for your platform. Where <OS> can be linux, mac or win
• $ npm test - run tests

Tray icon on Linux

The requirements for displaying a tray icon varies between different desktop environments. If the tray icon doesn't appear, try installing one of these packages:

• libappindicator3-1
• libappindicator1
• libappindicator

If you're using GNOME, try installing one of these GNOME Shell extensions:

• TopIconsFix
• TopIcons Plus

Repository structure

Electron app and electron-builder packaging assets

• desktop/packages/mullvad-vpn/
  • assets/ - Graphical assets and stylesheets
  • src/
    • main/
      • index.ts - Entry file for the main process
    • renderer/
      • app.tsx - Entry file for the renderer process
      • routes.tsx - Routes configurator
      • transitions.ts - Transition rules between views
    • config.json - App color definitions and URLs to external resources
  • tasks/ - Gulp tasks used to build app and watch for changes during development
    • distribution.js - Configuration for electron-builder
  • test/ - Electron GUI tests
• dist-assets/ - Icons, binaries and other files used when creating the distributables
  • binaries/ - Git submodule containing binaries bundled with the app. For example the statically linked OpenVPN binary. See the README in the submodule for details
  • linux/ - Scripts and configuration files for the deb and rpm artifacts
  • pkg-scripts/ - Scripts bundled with and executed by the macOS pkg installer
  • windows/ - Windows NSIS installer configuration and assets
  • ca.crt - The Mullvad relay server root CA. Bundled with the app and only OpenVPN relays signed by this CA are trusted

Building, testing and misc

• build-windows-modules.sh - Compiles the C++ libraries needed on Windows
• build.sh - Sanity checks the working directory state and then builds installers for the app

Mullvad Daemon

The daemon is implemented in Rust and is implemented in several crates. The main, or top level, crate that builds the final daemon binary is mullvad-daemon which then depend on the others.

In general one can look at the daemon as split into two parts, the crates starting with talpid and the crates starting with mullvad. The talpid crates are supposed to be completely unrelated to Mullvad specific things. A talpid crate is not allowed to know anything about the API through which the daemon fetch Mullvad account details or download VPN server lists for example. The talpid components should be viewed as a generic VPN client with extra privacy and anonymity preserving features. The crates having mullvad in their name on the other hand make use of the talpid components to build a secure and Mullvad specific VPN client.

• Cargo.toml - Main Rust workspace definition. See this file for which folders here are daemon Rust crates.
• mullvad-daemon/ - Main Rust crate building the daemon binary.
• talpid-core/ - Main crate of the VPN client implementation itself. Completely Mullvad agnostic privacy preserving VPN client library.

Vocabulary

Explanations for some common words used in the documentation and code in this repository.

• App - This entire product (everything in this repository) is the "Mullvad VPN App", or App for short.
  • Daemon - Refers to the mullvad-daemon Rust program. This headless program exposes a management interface that can be used to control the daemon
  • Frontend - Term used for any program or component that connects to the daemon management interface and allows a user to control the daemon.
    • GUI - The Electron + React program that is a graphical frontend for the Mullvad VPN App.
    • CLI - The Rust program named mullvad that is a terminal based frontend for the Mullvad VPN app.

File paths used by Mullvad VPN app

A list of file paths written to and read from by the various components of the Mullvad VPN app

Daemon

On Windows, when a process runs as a system service the variable %LOCALAPPDATA% expands to C:\Windows\system32\config\systemprofile\AppData\Local.

All directory paths are defined in, and fetched from, the mullvad-paths crate.

Settings

The settings directory can be changed by setting the MULLVAD_SETTINGS_DIR environment variable.

Logs

The log directory can be changed by setting the MULLVAD_LOG_DIR environment variable.

Cache

The cache directory can be changed by setting the MULLVAD_CACHE_DIR environment variable.

RPC address file

The full path to the RPC address file can be changed by setting the MULLVAD_RPC_SOCKET_PATH environment variable.

Desktop Electron app

The desktop Electron app has a specific settings file that is configured for each user. The path is set in the desktop/packages/mullvad-vpn/src/main/gui-settings.ts file.

Icons

See graphics README for information about icons.

Locales and translations

Instructions for how to handle locales and translations are found here.

For instructions specific to the Android app, see here.

Audits, pentests and external security reviews

Mullvad has used external pentesting companies to carry out security audits of this VPN app. Read more about them in the audits readme.

License

Copyright (C) 2024 Mullvad VPN AB

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

For the full license agreement, see the LICENSE.md file

The source code for the iOS app is GPL-3 licensed like everything else in this repository. But the distributed app on the Apple App Store is not GPL licensed, it falls under the Apple App Store EULA.