Power Management and Encryption

[feenberg-fCu/yNAGv6M at public.gmane.org (Daniel Feenberg)]

On Tue, 18 May 2010, Matthew Gillen wrote:

> On 05/17/2010 11:57 PM, Bill Bogstad wrote:
>> On Mon, May 17, 2010 at 9:10 PM, Matthew Gillen <me-5yx05kfkO/aqeI1yJSURBw at public.gmane.org> wrote:
>>> On 5/17/2010 4:50 PM, Daniel Feenberg wrote:
>>>>
>>>> We have a desktop Fedora 12 box with encrypted disks. This satisfies a
>>>> government agency worried about confidential data on the machine, but I
>>>> would like the data to revert to encrypted after X minutes of idle time.
>>>> The gnome-power-management GUI only provides for "sleeping" on idle and I
>>>> can't find the appropriate configuration files to improve on that, such as
>>>> by shutting down. I did test and found that one only needs input the Linux
>>>> password to gain access to the disk after sleeping, although if sleeping
>>>> could suitably unmount the encrypted disks, that would be fine also. (It
>>>> might be hard since it is full disk encryption, including the OS).
>>>
...

>
> So my original suggestion won't work.  You could try setting the
> /schemas/apps/gnome-power-manager/buttons/suspend
> key's value to 'shutdown' (that is a legal value for that key, the question is
> whether it treats all suspend events as 'suspend button' pushes).
>

We tried this - the GUI accepted the value "shutdown" in spite of not 
listing it as an accepted value. But idle time still results in sleep, not 
shutdown - the value seems to be ignored.

Further search on google suggests the only way to accomplish this is to 
write a cron job that periodically consults the "w" command for idle 
times. Apparently the powers that be think that an unexpected shutdown 
might cause violence to a running process, and have elected not to make it 
readily available.

In any case, thanks for the suggestions.

Daniel Feenberg
NBER

> If all else fails, this page might help you to customize HAL's actions when it
> gets told to suspend:
> http://chkno.net/hal-power-button.html
>
> HTH,
> Matt
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