Shortening the rope [LWN.net]

Shortening the rope

Posted Apr 3, 2009 19:38 UTC (Fri) by SLi (subscriber, #53131)
In reply to: Shortening the rope by joey
Parent article: Shortening the rope

Seriously, SAK is the one thing that is seriously lacking in Linux. The
Windows model of using Ctrl-Alt-delete for an uncatchable (by a non-root)
thing always before having to enter a password is really a good thing and
prevents malicious programs from capturing things. Although I hear the
implementation is not that good, but the idea is a correct one, and the
Linux world lacks even the idea. (There's a SAK in Magic SysRq and one can
be done with loadkeys, but they are not integrated at all with
X/KDE/Gnome/whatever and hence of limited use.)

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Shortening the rope

Posted Apr 7, 2009 13:34 UTC (Tue) by hmh (subscriber, #3838) [Link]

Properly done SAK should done by the kernel, for it to have a chance of being somewhat secure. It doesn't have to, nor should it be "integrated" to anything: that goes completely against what SAK is supposed to do.

What one should do is to make sure the kernel will select the correct crap for killing, and that it resets the VT (and the keyboard translation mode, damn PeeCee legacy crap) to something that can work with getty for when X doesn't come back up. And to have init or another process supervisor bring gdm/kdm back to life.

For all I know, it even already does the above :-) I should try it one of these days.

Shortening the rope

Posted Apr 19, 2009 9:44 UTC (Sun) by TRS-80 (subscriber, #1804) [Link]

With GDM at least, the SAK kills the child gdm process on the terminal, but not the parent daemon, which then spawns a new child that starts X. I tested this yesterday, as I needed to restart X to get back the 1.5GB of RAM mozilla had leaked into it. Keyboard-wise X should be using the same translation as the VT thanks to input-hotplug, not that there's a getty on that VT.