Migrating notes from Notion - Initial stage

content/notes/wsl2.md

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+---
+tags:
+  - notes
+  - os
+author: TrudeEH
+draft: false
+showToc: true
+title: WSL2
+---
+Windows' `WSL` allows for installing a Linux subsystem on a Windows host. `WSL2` enhances `WSL` with support for launching GUI apps as if they were regular Windows programs (or any [X.org](http://X.org) window).
+
+## Install WSL2
+
+On recent `WSL` versions, this process is quite simple:
+
+```PowerShell
+wsl --list --online           # See available distros
+wsl --install -d <distro>     # Select & Install distro
+wsl --set-default-version 2   # Set WSL 2 as the default version
+```
+
+If the previous steps fail, `WSL` can still be installed manually:
+
+```PowerShell
+# Enable WSL
+dism.exe /online /enable-feature /featurename:Microsoft-Windows-Subsystem-Linux /all /norestart
+# Enable VMP
+dism.exe /online /enable-feature /featurename:VirtualMachinePlatform /all /norestart
+# If the previous command fails:
+Enable-WindowsOptionalFeature -Online -FeatureName VirtualMachinePlatform -NoRestart
+wsl --set-default-version 2 # Set WSL 2 as the default version
+```
+
+Then, visit the Microsoft Store to download any distribution available. For this example, I selected [Ubuntu](https://www.microsoft.com/en-gb/p/ubuntu-2004-lts/9n6svws3rx71).  
+If Ubuntu was installed previously, it can be promoted to `WSL2` using the following command:
+
+```PowerShell
+wsl --set-version Ubuntu 2
+```
+
+## Encrypt WSL2 Disks
+
+To further isolate Linux files and programs from Windows, the home directory can be encrypted into a disk file. This also facilitates backups, as any user files will be stored there.
+
+### Setup the Disk
+
+This file will be later mounted as the current user's home directory, so it must be stored outside of it.
+
+> These commands are for `WSL`, not Windows Powershell.
+
+```Bash
+sudo install -o ${USER} -g ${USER} -d "/home/.${USER}"
+```
+
+Next, the file has to be populated. Usually, `EXT4` filesystems use 4kB block sizes. With this in mind, use the following formula to determine the number of blocks needed to fill the disk, where x is the result and y is the amount of space, in GB, that you want the disk to occupy.  
+
+$$x = y * 1024^2 / 4$$
+
+```Bash
+dd if=/dev/zero of="/home/.${USER}/disk.img" bs=4k count=<X> # Replace <X> with the result.
+sudo losetup /dev/loop0 "/home/.${USER}/disk.img"   # Setup the loopback device
+sudo cryptsetup -q luksFormat -y /dev/loop0         # Encrypt the disk with a password
+sudo cryptsetup open /dev/loop0 loop0               # Setup the decrypted block device
+sudo mkfs.ext4 /dev/mapper/loop0                    # Format the decrypted block device
+sudo mount /dev/mapper/loop0 "/home/${USER}"        # Mount the disk over your existing home directory
+sudo chown "${USER}:${USER}" "/home/${USER}"        # Fix permissions
+# Finally, get a new bash session with the new changes.
+bash -l; cd
+```
+
+### Helper Scripts
+
+To facilitate mounting and unmounting the encrypted disk, the following scripts can be useful:  
+**mount-home.sh**
+
+```Bash
+#!/bin/bash
+sudo echo -n
+cd /
+sudo losetup /dev/loop0 "/home/.${USER}/disk.img"
+sudo cryptsetup open /dev/loop0 loop0
+sudo mount /dev/mapper/loop0 "/home/${USER}"
+echo 'Home successfully mounted. Open a new terminal window or type: bash -l; cd'
+```
+
+> Add this script to your `.bashrc` to automate mounting the disk. If you do so, and later decide to undo your changes, you'll have to use an external editor, as `Bash` won't be able to load unless the correct password is provided.  
+
+**unmount-home.sh**
+
+```Bash
+#!/bin/bash
+cd /
+sudo umount /home/${USER}
+sudo cryptsetup close loop0
+sudo losetup -d /dev/loop0
+```