Systemd User PAM SSH script

This script has a rather specific use case. If you fit the following demographic then this script might just be for you!

• You use systemd
• You login at the linux VT using a getty
• You have a systemd --user service called ssh-agent.service that starts your ssh agent.
• You have to type your password a second time after logging in in order to decrypt your SSH key.

This script allows you to only type your password once. When logging in, your SSH key will be decrypted and added to your ssh-agent for you.

Usage

There is one pre-requisite for this script:

Your systemd --user instance needs to know about the SSH_AUTH_SOCK. If you're using my systemd-user-sessions package mentioned above then you will want to add this to your ~/.config/bash/environment file as something like SSH_AUTH_SOCK=$XDG_RUNTIME_DIR/ssh-agent.

To enable the script you will want to add this to your pam configuration (probably /etc/pam.d/system-login or /etc/pam.d/login)

auth  optional  pam_exec.so  expose_authtok /path/to/the/systemd-user-pam-ssh

Installation

I would recommend placing the script under /usr/lib/systemd/. If you are using Arch Linux you can use the PKGBUILD located here.