From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefano Stabellini Subject: Re: QEMU bumping memory bug analysis Date: Mon, 8 Jun 2015 14:45:10 +0100 Message-ID: References: <20150605164354.GK29102@zion.uk.xensource.com> <20150605181014.GM29102@zion.uk.xensource.com> <20150608131000.GC29102@zion.uk.xensource.com> <20150608133220.GE29102@zion.uk.xensource.com> <55759C25.4070402@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <55759C25.4070402@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Andrew Cooper Cc: Wei Liu , Ian Campbell , Stefano Stabellini , George Dunlap , Ian Jackson , dslutz@verizon.com, xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On Mon, 8 Jun 2015, Andrew Cooper wrote: > On 08/06/15 14:38, Stefano Stabellini wrote: > >> Also device-mode/$domid/state is writable by QEMU so we can't trust > >> > the content as indicator either. > > We can because the write happens before we unpause the guest > > Only when creating the domain fresh. On resume, the guest has possibly > had the chance to code-inject via the qemu save format. There are many > CVEs in this area, and I am not willing to be all of them are fixed. > > In XenServer, even loading VM state from the save file happens in the > deprivilelged environment. QEMU doesn't do any maxmem changes at restore time.