GBDE protecting the user?

[Michael W. Lucas]

Hi,

Been playing with GBDE a while, trying to make it protect me.

One of the features of GBDE is that it should "provide tangible
feedback" that the data has been destroyed. (See PHK's paper at
http://phk.freebsd.dk/pubs/bsdcon-03.gbde.paper.pdf, section 4.1.)

The man page doesn't mention this, so what the heck, I decided to play
with it.

Creating GBDE devices is very simple.

# gbde init /dev/gpt/encrypted -L /etc/encrypted.lock

I created a filesystem, mounted it, put files on it, unmounted.

There's two operations to wipe out a GBDE: nuke and destroy. Nuke
looks like the right thing. I nuke all the keys:

# gbde nuke gpt/encrypted -l /etc/encrypted.lock -n -1
Enter passphrase:
Opened with key 0
Nuked key 0
Nuked key 1
Nuked key 2
Nuked key 3
# gbde attach gpt/encrypted -l /etc/encrypted.lock
Enter passphrase:
#

The .bde device isn't there, and my filesystem is gone. But I received
no confirmation that the keys were destroyed.

I also didn't get a message that the device couldn't be attached,
although it clearly isn't.

Fine. Let's try gbde destroy.

gbde init /dev/gpt/encrypted -L /etc/encrypted.lock
Enter new passphrase:
Reenter new passphrase:
# gbde destroy gpt/encrypted -l /etc/encrypted.lock
Enter passphrase:
Opened with key 0
# gbde attach gpt/encrypted -l /etc/encrypted.lock
Enter passphrase:
# 

The device isn't attached, it just fails silently.

Did I misunderstand the GBDE functionality? Am I missing something
daft? Has this code just decayed with GELI's arrival?

Thanks,
==ml
-- 
Michael W. Lucas  -  mwlucas at michaelwlucas.com, Twitter @mwlauthor 
http://www.MichaelWLucas.com/, http://blather.MichaelWLucas.com/