[sclug] Disable 'Ctrl-Alt-Del' reboots

[Alex Butcher]

On Wed, 2 Feb 2005, John Stumbles wrote:

> Alex Butcher wrote:
>
>> I was not pointing out that DoS by C-A-D was a serious threat, just that it
>> seems incongruous to have C-A-D enabled, but Magic SysRq disabled. I guess
>> the differentiator is that Magic SysRq can cause filesystem damage (e.g.
>> SysRq+O or SysRq+B without a SysRq+U first) whereas C-A-D shouldn't.
>
> Pray what is Magic SysRq? (Inferring from the context above I'm not trying it 
> at home :-)

Read /usr/src/linux/Documentation/sysrq.txt for the details. Essentially,
it's a low-level hook that allows you to dump the current registers, process
table and memory allocations as well as power down (via APM/ACPI), emergency
unmount and sync and reboot.

> And talking about masonic handshakes, anyone know if it's possible to change 
> the behaviour of Ctrl-Alt-Backspace in X?

Change as in 'enable or disable' - yes; read up on the 'DontZap' ServerFlag.

Change in any other way? Sure, if you're prepared to hack the source. ;-)

Best Regards,
Alex.
-- 
Alex Butcher      Brainbench MVP for Internet Security: www.brainbench.com
Bristol, UK                      Need reliable and secure network systems?
PGP/GnuPG ID:0x271fd950                         <http://www.assursys.com/>