From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49207) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UsBlp-0006Q8-KZ for qemu-devel@nongnu.org; Thu, 27 Jun 2013 08:57:58 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UsBln-0006gm-F3 for qemu-devel@nongnu.org; Thu, 27 Jun 2013 08:57:53 -0400 Received: from mx1.redhat.com ([209.132.183.28]:20835) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UsBln-0006gT-5v for qemu-devel@nongnu.org; Thu, 27 Jun 2013 08:57:51 -0400 Date: Thu, 27 Jun 2013 13:57:43 +0100 From: "Daniel P. Berrange" Message-ID: <20130627125743.GJ2621@redhat.com> References: <20130627093616.GA2621@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Subject: Re: [Qemu-devel] qemu-img create encryption Reply-To: "Daniel P. Berrange" List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Hamilton, Peter A." Cc: "qemu-devel@nongnu.org" On Thu, Jun 27, 2013 at 08:05:38AM -0400, Hamilton, Peter A. wrote: > > It also means you can't change the password of an existing image - you have > > to create a new image with a new password & re-encrypt the data. > > Following up on this point, since "qemu-img create" cannot be used to specify > a password, is "qemu-img convert" the only command that can be used to provide Any command which actually reads/writes data will take a password. So, yes, I'd expect 'convert' to ask for one. > one? Furthermore, since "convert" conducts a full copy of the source image, > does this mean that it is not possible to have an encrypted CoW image with an > encrypted backing file, where each is encrypted with a different password? The > tests I have conducted up to this point seem to indicate that this is true. I'm honestly not too sure about the status of encryption wrt backing stores. I wouldn't surprise me if you needed to use the same password for both the top & lower level backing files. Equally though, there's no technical reason why this should be required - just an impl limitation, if true. Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|