From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41386) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1acyjL-00042n-4k for qemu-devel@nongnu.org; Mon, 07 Mar 2016 12:14:03 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1acyjH-0005jq-E4 for qemu-devel@nongnu.org; Mon, 07 Mar 2016 12:14:03 -0500 Received: from mx1.redhat.com ([209.132.183.28]:45895) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1acyjH-0005jf-8u for qemu-devel@nongnu.org; Mon, 07 Mar 2016 12:13:59 -0500 References: <20160303143501.0edf21a2@redhat.com> <20160304111933.GB626@stefanha-x1.localdomain> <20160304082311.5ccd1a33@gandalf.local.home> <20160307151705.GD20937@stefanha-x1.localdomain> <20160307104924.1871dbdb@gandalf.local.home> <56DDA7E2.3050506@redhat.com> <20160307112627.3b94c671@gandalf.local.home> From: Paolo Bonzini Message-ID: <56DDB6D0.7020308@redhat.com> Date: Mon, 7 Mar 2016 18:13:52 +0100 MIME-Version: 1.0 In-Reply-To: <20160307112627.3b94c671@gandalf.local.home> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC] host and guest kernel trace merging List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Steven Rostedt , Eric Blake Cc: kvm@vger.kernel.org, Stefan Hajnoczi , yoshihiro.yunomae.ez@hitachi.com, mtosatti@redhat.com, qemu-devel@nongnu.org, peterx@redhat.com, Luiz Capitulino , linux-trace-users@vger.kernel.org, Stefan Hajnoczi On 07/03/2016 17:26, Steven Rostedt wrote: > > > How's the connection set up. That is, how does it know the commands are > > > coming from the host? And how does it know that the commands from the > > > host is from a trusted source? If the host is compromised, is there > > > anything keeping an intruder from controlling the guest? > > > > qemu-guest-agent uses a virtio channel, so only the host can be driving > > that channel. But how can a guest know that it trusts the host? It > > can't. A compromised host implicitly compromises all guests, and that's > > always been the case. At least qemu-guest-agent doesn't make the window > > any larger. > > I should have been a bit more clear about what I meant by "host is > compromised". I should have asked, what about untrusted tasks on the > host. Is the channel protected where only admin users can access it? The other side of the channel is typically a socket or a pty, so it's protected by file permissions, SELinux, and the like. Paolo