From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <glkdd-dm-crypt@m.gmane.org>
Received: from blaine.gmane.org (unknown [195.159.176.226])
 (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits))
 (No client certificate requested)
 by mail.server123.net (Postfix) with ESMTPS
 for <dm-crypt@saout.de>; Thu, 13 Apr 2017 15:21:54 +0200 (CEST)
Received: from list by blaine.gmane.org with local (Exim 4.84_2)
 (envelope-from <glkdd-dm-crypt@m.gmane.org>) id 1cyeh1-0006dZ-8k
 for dm-crypt@saout.de; Thu, 13 Apr 2017 15:21:47 +0200
From: Robert Nichols <rnicholsNOSPAM@comcast.net>
Date: Thu, 13 Apr 2017 08:21:47 -0500
Message-ID: <ocnu15$ogs$1@blaine.gmane.org>
References: <d0cba900-05da-2be0-caaa-03014302a933@mail.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=windows-1252; format=flowed
Content-Transfer-Encoding: 7bit
In-Reply-To: <d0cba900-05da-2be0-caaa-03014302a933@mail.com>
Subject: Re: [dm-crypt] Detached header offset
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 04/13/2017 05:18 AM, 7heo wrote:
>
> So is there a way to place a detached header arbitrarily on a disk, and not at the start of a partition?

It's not supported within cryptsetup, but you can always use "losetup" to create a loop device starting at the needed offset and then specify that loop device as the detached header:

     Loopdev=$(losetup -f --show -o 65536 /dev/{whatever}
     cryptsetup luksOpen --header $Loopdev ...
     losetup -d $Loopdev

-- 
Bob Nichols     "NOSPAM" is really part of my email address.
                 Do NOT delete it.