... is a tool that receives user's credentials during authentication phase and keeps it for later use. Any tool that want to benefit from it has to implement a "manage_cred's extension" by adding a Python file in /usr/local/lib/manage_cred/ that implements both :

1. FLAG_FILE : points to a file that reports that this extension expects to be run
2. run : function that will receive both the username and the password in order to perform the commands needing the credentials.

The files related to manage_cred :

• /etc/pam.d/common-auth Says that PAM has to run manage_cred.py at authentication step with credentials exposed
• /usr/local/bin/manage_cred.py Main script
• /usr/local/lib/manage_cred Folder that will contain all extensions

... is a tool that stores selected application's config/preferences on the NAS. This is configured by adding right the folders, files and DConf keys in /usr/local/etc/epfl_roaming.conf. With epfl_roaming, the users have a clean session (created from /etc/skel) at every login, plus the important application's settings available across all PCs in a classroom. It directly needs manage_cred, since it has to mount the NAS during session creation at a time when we don't receive the password from PAM.

The files related to epfl_roaming :

• /etc/pam.d/common-session Says that PAM has to run epfl_roaming.py --pam at session opening and closing. Most of the job is done here.
• /etc/skel/.config/autostart/epfl_roaming.desktop Says that Gnome/Unity has to run epfl_roaming.py --session when session is opened (used to apply DConf keys)
• /etc/systemd/system/epfl_roaming_on_shutdown.service Says that systemd has to run epfl_roaming.py --on_halt when the system is shut down or rebooted (since PAM procedure might be skipped or aborted)
• /usr/local/bin/epfl_roaming.py Main script
• /usr/local/etc/epfl_roaming.conf Configuration. This File has to be customized to :
  • replace the path ChangeMeToResponsibleTeam/pool to the expected one
  • choose what app's prefs have to be roaming
• /usr/local/lib/manage_cred/ext_epfl_roaming.py manage_cred's extension for epfl_roaming

sudo make install

Note : This process has been validated on Ubuntu 18.04. Adaptations will be needed for Ubuntu 14.04 or other GNU/Linux flavors.