> So how is dropping privileges done correctly to avoid getting killed by the user? I think you got the wrong idea from the article, which is partly author's f

> So how is dropping privileges done correctly to avoid getting killed by the user? I think you got the wrong idea from the article, which is partly author's fault. He claims user should not be able to do that, but that is a highly anti-user anti-unix viewpoint. Creating a destroying (crashing) processes running with uid of any non-root user is something like an obvious inalienable right of that unix user. It is expected that this works. The problem to solve is that the crash of the user daemon confuses gdm (a root process) which then behaves as if the computer is in the installation phase and the user is to be trusted with setting up high-privilege account. The solution for Ubuntu is obvious, fix gdm. For administrators / power users, use something simpler such as xdm, where these kinds of errors are unlikely to occur.