From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40315) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W602Z-0002oE-Ef for qemu-devel@nongnu.org; Wed, 22 Jan 2014 10:48:35 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1W602V-0002mY-9B for qemu-devel@nongnu.org; Wed, 22 Jan 2014 10:48:31 -0500 Received: from mx1.redhat.com ([209.132.183.28]:10353) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W602U-0002mK-W0 for qemu-devel@nongnu.org; Wed, 22 Jan 2014 10:48:27 -0500 Date: Wed, 22 Jan 2014 15:48:19 +0000 From: "Daniel P. Berrange" Message-ID: <20140122154819.GY9434@redhat.com> References: <1390393704-16067-1-git-send-email-berrange@redhat.com> <52DFE290.5080401@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <52DFE290.5080401@redhat.com> Subject: Re: [Qemu-devel] [PATCH v2] Describe flaws in qcow/qcow2 encryption in the docs Reply-To: "Daniel P. Berrange" List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eric Blake Cc: Kevin Wolf , Paolo Bonzini , qemu-devel@nongnu.org, Stefan Hajnoczi , Peter Maydell On Wed, Jan 22, 2014 at 08:24:00AM -0700, Eric Blake wrote: > On 01/22/2014 05:28 AM, Daniel P. Berrange wrote: > > > > > Recommend against any use of QCow/QCow2 encryption, directing > > users to dm-crypt / LUKS which can meet modern cryptography > > best practices. > > > > Signed-off-by: Daniel P. Berrange > > --- > > qemu-doc.texi | 23 ++++++++++++++++++++--- > > qemu-img.texi | 23 ++++++++++++++++++++--- > > 2 files changed, 40 insertions(+), 6 deletions(-) > > > + > > +@itemize @minus > > +@item The AES-CBC cipher is used with predictable initialization vectors based > > +on the sector number. This makes it vulnerable to chosen plaintext attacks > > +which can reveal the existence of encrypted data. > > +@item The user passphrase is directly used as the encryption key. A poorly > > +choosen or short passphrase will compromise the security of the encryption. > > s/choosen/chosen/ (both files) > > > +In the event of the passphrase being compromised there is no way to change > > and still my question whether this deserves a third @item. I was considering this to be a result of using the passphrase as the key. It does however read better if split out, so I've made that change. 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 :|