From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33198) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bguRe-0006hA-DH for qemu-devel@nongnu.org; Mon, 05 Sep 2016 10:00:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bguRZ-0004vO-2k for qemu-devel@nongnu.org; Mon, 05 Sep 2016 10:00:17 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52126) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bguRY-0004v2-UV for qemu-devel@nongnu.org; Mon, 05 Sep 2016 10:00:13 -0400 Date: Mon, 5 Sep 2016 15:00:09 +0100 From: "Daniel P. Berrange" Message-ID: <20160905140009.GE24656@redhat.com> Reply-To: "Daniel P. Berrange" References: <110743700.1285610.1472475080274.ref@mail.yahoo.com> <110743700.1285610.1472475080274@mail.yahoo.com> <20160905135214.GA22496@work-vm> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20160905135214.GA22496@work-vm> Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] A question about postcopy safety List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Dr. David Alan Gilbert" Cc: liutgnu@yahoo.com, qemu-devel@nongnu.org On Mon, Sep 05, 2016 at 02:52:14PM +0100, Dr. David Alan Gilbert wrote: > * liutgnu@yahoo.com (liutgnu@yahoo.com) wrote: > > Hi=C2=A0David, >=20 > Hi Liutao, >=20 > > I'm studying the process of postcopy migration, and I found that the = memory pages migrated from source to destination are not encrypted. Does = this make the VM vulnerable if it's memory has been tampered with during = postcopy migration? > >=20 > > I think precopy has less risk because the source's memory is always a= ltering. If one page is tampered with during network transfer, with sourc= e still running, then a later version of that page may keep updating. So = it would be quite difficult to track all different page versions, and tam= per with the final version of one page. > >=20 > > But when it comes to postcopy, the situation is riskier because one s= pecific page is only transferred once. It's easy to capture all transferr= ing memory pages, tamper and resend. >=20 > I don't think there's much difference between precopy and postcopy for = security; > the only secure way to do migration is over an encrypted transport and = that solves > it for both precopy and postcopy. Agreed, there's no real world difference in the security of pre & post co= py. If you care about security there's no avoiding the need to use an encrypt= ed transport. Regards, Daniel --=20 |: http://berrange.com -o- http://www.flickr.com/photos/dberrange= / :| |: http://libvirt.org -o- http://virt-manager.or= g :| |: http://autobuild.org -o- http://search.cpan.org/~danberr= / :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vn= c :|