Users

It might be nice to add a user to your system.

Doas

Before creating the user install doas for when root is requiered:

# apk add doas

Also configure doas through /etc/doas.d/main.conf:

permit persist :wheel as root
permit nopasss :_power cmd poweroff
permit nopasss :_power cmd reboot

And create a _power group for user's to be able to poweroff the system without root:

# addgroup -S _power

Adding a user

Adding a user in alpine can be done using the setup-user script. Here we can specify the name, fullname, groups and more:

# setup-user -g wheel,plugdev,_seatd,nix,_power -f "<Full Name>" <username>
# passwd <username>

And you (might) have to change the shell of the user in /etc/passwd from /sbin/nologin to a shell from /etc/shells. Alpine Linux comes with /bin/ash by default:

<username>:x:1234:1234:<Full Name>:/home/<username>:/bin/<shell>

It's also recommended to have an "admin" account which is the only one in the wheel group.

Don't login yet if you want to encrypt the directory.

If you have checked that doas works with the user then you can lock the root account because it's insecure to keep open. This can be done with:

# passwd -l root

And editing /etc/passwd to change the login shell from /bin/ash to /sbin/nologin:

root:x:0:0:root:/root:/sbin/nologin

Encrypting the home directory

If you are running a system with multiple users or if you want an extra layer of protection then it's possible to encrypt every user's home directory.

Do note that a second layer of encryption can lead to lower disk performance so in the case where this is important it might be preferred not to encrypt.

Setup

First install the fscrypt, e2fsprogs-extra and util-linux-login packages:

# apk add fscrypt e2fsprogs-extra util-linux-login

Then make sure our filesystem has the encrypt feature enabled and setup fscrypt on the home directory:

# tune2fs -O encrypt /dev/vg<m>/home<n>
# fscrypt setup
# fscrypt setup /home

And edit /etc/pam.d/login and adding these lines to their corresponding sections:

auth     optional    pam_fscrypt.so
...
session  optional    pam_fscrypt.so

Encrypting a user's home

Encrypt the directory with:

# fscrypt encrypt /home/<username> --user=<username>
[Create a new login protector]
[Enter 1 so that it unlocks the directory when the user logs in]

Then reboot and login with the user to check if it worked. It should also have given you a recovery password which should be stored somewhere safely (like Bitwarden). To check the status of the directory run:

$ fscrypt status /home/<username>

TLDR

If you have already set up a system with a user but want to add another do this:

# setup-user -g (wheel,)plugdev,_seatd,nix,_power -f "<Full Name>" <username>
# passwd <username>
[Change shell in /etc/passwd]
# fscrypt encrypt /home/<username> --user=<username>
[Create a new login protector]
[Enter 1 so that it unlocks the directory when the user logs in]

3 KiB Raw Blame History