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Date:      Wed, 16 Feb 2000 11:29:30 +1030
From:      Greg Lehey <grog@lemis.com>
To:        Richard Cotrina <rcc@demo.telefonica.com.pe>
Cc:        freebsd-questions@FreeBSD.ORG
Subject:   Re: CTR+ALT+DEL Sequence
Message-ID:  <20000216112930.G12517@freebie.lemis.com>
In-Reply-To: <007b01bf77ec$f75dcc90$4d01190a@tp.com.pe>
References:  <007b01bf77ec$f75dcc90$4d01190a@tp.com.pe>

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On Tuesday, 15 February 2000 at 14:43:42 -0500, Richard Cotrina wrote:
> Hi Folks:
>
> I found out that anyone can force a shutdown in my FreeBSD box using the
> CTR+AL+DEL Keyboard Sequence at the console. I don't know if it is a bug ,
> but I would like to know if there is something to fix or block this keyboard
> sequence.  I am running a FreeBSD 3.4-Release Box.
>
> However, It doesn't happen when the console is in graphic (X-Win) mode ,
> only works in character mode.
>
> Any points would be appreciated. Thanks in Advance.

Basically, the feeling is "If they can get at the keyboard, they can
usually get at the machine and pull the plug.  This will shut the
machine down too, just not as cleanly."

You can disable the feature by setting a new keymap.  See
kbdcontrol(8) and the files in /usr/share/syscons/keymaps.  For
example, you might start with /usr/share/syscons/keymaps/us.iso.kbd,
which contains the line

  083   del    '.'    '.'    '.'    '.'    '.'    boot   boot    N

Make a copy, say us.iso.mykbd, and change this line to:

  083   del    '.'    '.'    '.'    '.'    '.'    '.'     '.'    N

and reload the keymap:

# kbdcontrol -l /usr/share/syscons/keymaps/us.iso.mykbd

You can set this to happen automatically by putting the appropriate
entry in /etc/rc.conf:

keymap="us.iso.mykbd"	

Greg
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