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I'm planning an exhibition where I need to run an app which needs a keyboard, but no mouse. I want to lock the viewers into one fullscreen application. They should never be able to see anything except this one app. Nothing whatsoever.
So I'd set up a new user which will start the app (in fullscreen mode) as soon as the user logs in. The machine it's running on will be physically secured.
But they have access to the keyboard and could do unwanted things (even closing or switching applications is unwanted). Is there any way of preventing all keyboard based application switching, launching, shutting down, access to tty, login prompt... - such that the only way to leave the application (or simply see anything else) is using the power off button on the (secured) hardware?
The app is intended for Ubuntu 17.10.