:: Re: [DNG] F1 and special usernames …
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Author: Didier Kryn
Date:  
To: dng
Subject: Re: [DNG] F1 and special usernames on the login screen
Le 21/07/2016 04:15, Adam Borowski a écrit :
> On Wed, Jul 20, 2016 at 06:27:25PM -0700, Rick Moen wrote:
>> Quoting Didier Kryn (kryn@???):
>>> In any case, any person who has the possibility to push the
>>> power button or cut the power cord should be given the opportunity
>>> to click the halt button instead. ctrl-alt-f1+ctrl-alt-del can be
>>> used to reboot, but there's nothing to halt.
>> Halt is accomplished by first doing ctrl-alt-f1, ctrl-alt-del, then
>> turning the system unit off before significantly into startup (assuming
>> physical access to the system unit in addition to a physical console).
>>
>> Or, as you say, through a hardware button on the system unit, or yanking
>> the mains (AC) cord.
> Which means the defaults for display managers are bogus.
>
> In the default configuration, anyone with physical access can ctrl-alt-del
> or alt-sysrq. This can be disabled, so can be a brief push of the power
> button (ACPI shutdown), but I have yet to see a BIOS that allows disabling
> long push of the power button, or, for that matter, yanking the power cord
> (or the battery of a mobile device).

     Long-push always worked for me. And short-push worked for me on 
Slim - I've now replaced Slim by Lightdm. Dunno what key "sysrq" is.

> Thus, unless someone took extraordinary steps to provide physical security,
> anyone able to login locally can turn the machine off, period. An orderly
> shutdown is better than an unclean one, thus any display manager that
> forbids local users to shutdown is buggy.
>

     I think anyone could agree on this. And this means "no 
authentication required."


     Didier