Re: [gentoo-user] How to poweroff the system from user?

[Rich Freeman]

On Sun, Mar 29, 2015 at 7:20 PM, Walter Dnes <waltdnes@××××××××.org> wrote:
> On Sun, Mar 29, 2015 at 12:43:12PM +0200, lee wrote
>
>> That leaves the question why a user who isn't even logged in should
>> be able to reboot, which IIRC they can by default with Ctrl+Alt+Del.
>> Such users shouldn't be allowed to do anything but to log in.
>
>   As the old saying goes... "If you don't have physical security, you
> don't have any security".  A malicious person at the physical keyboard
> of the machine could just as easily yank the power cord of out of the
> wall, insert a USB key into the machine, plug the machine back in, boot
> up from the USB key, and copy over malicious binaries.
>

With TPM, full-disk encryption, and a verified boot path, you could
actually protect against that scenario (they'd have to tear apart the
TPM chip and try to access the non-volatile storage directly, and the
chips are specifically designed to defeat this).  Secure boot would
not hurt either (with your own keys).  Of course, they could still try
to hack in via USB/PCI/etc, or plant keyloggers and such.  I'm not
suggesting physical security isn't important.  It just isn't a good
reason to completely neglect console security.

-- 
Rich