From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44988) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1at0V2-0004d7-KZ for qemu-devel@nongnu.org; Wed, 20 Apr 2016 18:21:33 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1at0Uy-0003GZ-Bc for qemu-devel@nongnu.org; Wed, 20 Apr 2016 18:21:32 -0400 Received: from mx1.redhat.com ([209.132.183.28]:32984) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1at0Uy-0003GV-6Z for qemu-devel@nongnu.org; Wed, 20 Apr 2016 18:21:28 -0400 References: <5710C55E.3030000@redhat.com> From: Cole Robinson Message-ID: <571800E4.4040207@redhat.com> Date: Wed, 20 Apr 2016 18:21:24 -0400 MIME-Version: 1.0 In-Reply-To: <5710C55E.3030000@redhat.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] RFC: virtio-rng and /dev/urandom List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: libvirt-list@redhat.com, qemu-devel Cc: "Richard W.M. Jones" , "Daniel P. Berrange" , Peter Krempa , Amit Shah , mik@miknet.net, jjaburek@redhat.com, hkario@redhat.com, sgrubb@redhat.com, hpa@zytor.com, Paolo Bonzini , Eric Blake On 04/15/2016 06:41 AM, Cole Robinson wrote: > Libvirt currently rejects using host /dev/urandom as an input source for a > virtio-rng device. The only accepted sources are /dev/random and /dev/hwrng. > This is the result of discussions on qemu-devel around when the feature was > first added (2013). Examples: > > http://lists.gnu.org/archive/html/qemu-devel/2012-09/msg02387.html > https://lists.gnu.org/archive/html/qemu-devel/2013-03/threads.html#00023 > > libvirt's rejection of /dev/urandom has generated some complaints from users: > > https://bugzilla.redhat.com/show_bug.cgi?id=1074464 > * cited: http://www.2uo.de/myths-about-urandom/ > http://www.redhat.com/archives/libvir-list/2016-March/msg01062.html > http://www.redhat.com/archives/libvir-list/2016-April/msg00186.html > > I think it's worth having another discussion about this, at least with a > recent argument in one place so we can put it to bed. I'm CCing a bunch of > people. I think the questions are: > > 1) is the original recommendation to never use virtio-rng+/dev/urandom correct? > > 2) regardless of #1, should we continue to reject that config in libvirt? > Even though there's still a debate about whether use of /dev/urandom here is sensible, several people suggested removing the libvirt path restriction, and nobody really spoke up to defend it. So I've posted a patch to fully drop libvirt's rng path whitelist: http://www.redhat.com/archives/libvir-list/2016-April/msg01362.html - Cole