From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <dpchrist@holgerdanske.com>
Received: from holgerdanske.com (holgerdanske.com
 [IPv6:2001:470:0:19b::b869:801b])
 by mail.server123.net (Postfix) with SMTP
 for <dm-crypt@saout.de>; Wed,  6 Apr 2016 07:59:18 +0200 (CEST)
Received: from ::ffff:99.100.19.101 ([99.100.19.101]) by holgerdanske.com
 for <dm-crypt@saout.de>; Tue, 5 Apr 2016 22:59:15 -0700
References: <57048FA2.7090008@holgerdanske.com> <5704A0C7.2040707@gmail.com>
From: David Christensen <dpchrist@holgerdanske.com>
Message-ID: <5704A5C5.4000002@holgerdanske.com>
Date: Tue, 5 Apr 2016 22:59:33 -0700
MIME-Version: 1.0
In-Reply-To: <5704A0C7.2040707@gmail.com>
Content-Type: text/plain; charset=windows-1252; format=flowed
Content-Transfer-Encoding: 7bit
Subject: Re: [dm-crypt] Debian 7.10 random key swap Device /dev/sda2 is not
 a valid LUKS device.
List-Id: <dm-crypt.saout.de>
List-Unsubscribe: <http://www.saout.de/mailman/options/dm-crypt>,
 <mailto:dm-crypt-request@saout.de?subject=unsubscribe>
List-Archive: <http://www.saout.de/pipermail/dm-crypt/>
List-Post: <mailto:dm-crypt@saout.de>
List-Help: <mailto:dm-crypt-request@saout.de?subject=help>
List-Subscribe: <http://www.saout.de/mailman/listinfo/dm-crypt>,
 <mailto:dm-crypt-request@saout.de?subject=subscribe>
To: dm-crypt@saout.de

On 04/05/2016 10:38 PM, Milan Broz wrote:
> On 04/06/2016 06:25 AM, David Christensen wrote:
> LUKS device cannot be used with random volume key, so I guess you use
> just plain device without header. (So obviously header backup fails because
> there is no header.)

Thank you for the information.


>
> You can verify it by checking entry in /etc/crypttab - no luks keyword:
>
>> # grep sda2 /etc/fstab
>> /dev/mapper/sda2_crypt                    none                    swap
>
> or running "cryptsetup status sda2_crypt" over unlocked device
> (type is LUKS1 for LUKS devices)

# cryptsetup status sda2_crypt
/dev/mapper/sda2_crypt is active and is in use.
   type:    PLAIN
   cipher:  aes-xts-plain64
   keysize: 256 bits
   device:  /dev/sda2
   offset:  0 sectors
   size:    976896 sectors
   mode:    read/write


So, what I'm seeing is expected and correct, because a random-key 
encrypted swap uses dm-crypt on the raw partition, there is no LUKS 
container, and therefore no LUKS header to back up (?).


David