For a public surfstation available for free we needed to have a system, that just simply always works. No user should be able to reset any configuration-settins, change the wallpaper, modify favorites or anything like that. The decision of the operating system was easy: Linux!
The needed tasks to install this system are the following:
- Download and install Ubuntu (the “Gnome Edition”) with all updates (there should be tons of howtos for this in the net)
- During the installation create a user that will be automatically logged in.
- Disable all keyboard-shortcuts in the system-settings dialogue.
- Install the following two addons in Firefox: BlockSite and OpenKiosk
In the OpenKiosk Adminscreen (can be started directly from Firefox) you can customize your “hardened” Firefox. I personally set fullscreen mode, increased the reset interval to 3 minutes, enabled a 30 seconds warning before the reset and removed the Print button and zoom controls.
- Configure Firefox to start automatically when the user logs in.
- Create the file /etc/X11/xorg.conf with the following content. This disables the Ctrl+Alt+F1,Ctrl+Alt+F2, etc. shortcuts for switching through the gettys.
Option "DontVTSwitch" "true"
- Mount the root Filesystem readonly with the aufs Filesystem. This ensures that a reboot of the Surfstation/Terminal resets everything to default settings (although there shouldn’t be many changes besides the browser history) Here is a great Tutorial for that.