privsec.dev/content/posts/qubes/Using Mullvad VPN on Qubes OS.md

---
title: "Using Mullvad VPN on Qubes OS"
date: 2022-09-03
tags: ['Applications', 'Qubes OS', 'Privacy']
author: Tommy
---

![Mullvad VPN](/images/mullvad-vpn.png)

Mullvad is a fairly popular and generally trustworthy VPN provider. In this post, I will walk you through how to use the official Mullvad client in a ProxyVM on Qubes OS. This method is a lot more convenient than the [official guide](https://mullvad.net/en/help/qubes-os-4-and-mullvad-vpn/) from Mullvad (which recommends that you manually load in OpenVPN or Wireguard profiles) and will let you seamlessly switch between different location and network setups just as you would on a normal Linux installation.

## Preparing your TemplateVM

I recommend that you make a new TemplateVM based on the latest Fedora GNOME template and remove all unnecessary packages that you might not use. This way, you can minimize the attack surface while not having to deal with missing dependencies like on a minimal template. With that being said, if you do manage to get the minimal template to fully work with Mullvad, feel free to [open a discussion on GitHub](https://github.com/orgs/PrivSec-dev/discussions) or [contact me directly](https://tommytran.io/contact) and I will update the post accordingly.

I run [this script](https://github.com/TommyTran732/QubesOS-Scripts/blob/main/fedora-gnome/fedora-gnome.sh) on my template to trim it down.

Next, you need to create the bind directories for Mullvad's configurations:

```bash
sudo mkdir -p /etc/qubes-bind-dirs.d
echo 'binds+=( '\'''/etc/mullvad-vpn''\'' )' | sudo tee /etc/qubes-bind-dirs.d/50_user.conf 
```

## Installing the Mullvad App

Inside of the TemplateVM you have just created, do the following:

```bash
sudo dnf config-manager --add-repo https://repository.mullvad.net/rpm/stable/mullvad.repo
sudo dnf install -y mullvad-vpn
```

To work around [issue 3803](https://github.com/mullvad/mullvadvpn-app/issues/3803), we will be using systemd path to run `/usr/lib/qubes/qubes-setup-dnat-to-ns` every time Mullvad modifies `/etc/resolv.conf`. Create the following files:

- `/etc/systemd/system/dnat-to-ns.service`
```
[Unit]
Description=Run /usr/lib/qubes/qubes-setup-dnat-to-ns
StartLimitIntervalSec=0

[Service]
Type=oneshot
ExecStart=/usr/bin/systemctl restart systemd-resolved
ExecStart=/usr/lib/qubes/qubes-setup-dnat-to-ns
```

- `/etc/systemd/system/dnat-to-ns.path`

```
[Unit]
Description=Run /usr/lib/qubes/qubes-setup-dnat-to-ns when /etc/resolv.conf changes

[Path]
PathChanged=/etc/resolv.conf
Unit=dnat-to-ns.service

[Install]
WantedBy=multi-user.target
```

Create `/etc/systemd/system/systemd-resolved.conf.d/override.conf` to disable rate limiting on systemd-resolved restarting:

```
[Unit]
StartLimitIntervalSec=0
```

Next, enable the systemd path:

```bash
sudo systemctl enable dnat-to-ns.path
```

Finally, shut down the TemplateVM:

```bash
sudo shutdown now
```

## Creating the ProxyVM

Create an AppVM based on the TemplateVM you have just created. Set `sys-firewall` (or whatever FirewallVM you have connected to your `sys-net`) as the net qube. If you do not have such FirewallVM, use `sys-net` as the net qube. Next, go to the advanced tab and tick the `provides network access to other qubes` box.

![Provides Network](/images/provides-network.png)

Open the Mullvad VPN app. Go to `Settings` → `VPN settings` and toggle `Local network sharing`. Due to some strange interaction between qubes services and Mullvad VPN, certain apps will get internet connections while others do not if this toggle is not enabled. This toggle will **not** actually allow AppVMs connected to the ProxyVM to connect to the local network.

Enable `Lockdown mode` to ensure that the killswitch stays on even when the tunnel is disconnected.

## Additional Assurances

For additional assurances against VPN leaks, you can optionally add these 2 lines to `/rw/config/qubes-firewall-user-script`:

```bash
nft add rule qubes custom-forward oifname eth0 counter drop
nft add rule ip6 qubes custom-forward oifname eth0 counter drop
```

This is not strictly necessary, as I have not observed any leaks with the VPN killswitch provided by the app.

## Notes

With this current setup, the ProxyVM you have just created will be responsible for handling Firewall rules for the qubes behind it. This is not ideal, as this is still a fairly large VM, and there is a risk that Mullvad or some other apps may interfere with its firewall handling.

Instead, I highly recommend that you [create a minimal Mirage FirewallVM](/posts/qubes/firewalling-with-mirageos-on-qubes-os/) and use it as a firewall **behind** the Mullvad ProxyVM. Other AppVMs then should use the Mirage Firewall as the net qube instead. This way, you can make sure that firewall rules are properly enforced.

![MirageOS](/images/mirageos.png)