From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753100AbaHMUbs (ORCPT ); Wed, 13 Aug 2014 16:31:48 -0400 Received: from ozlabs.org ([103.22.144.67]:55980 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751429AbaHMUbr (ORCPT ); Wed, 13 Aug 2014 16:31:47 -0400 From: Rusty Russell To: "Linus Torvalds" Cc: linux-kernel@vger.kernel.org Cc: hpa@linux.intel.com, Amos Kong , ricardo.neri-calderon@linux.intel.com, tytso@mit.edu, Amit Shah Subject: [PATCH] virtio: rng: add derating factor for use by hwrng core User-Agent: Notmuch/0.17 (http://notmuchmail.org) Emacs/24.3.1 (x86_64-pc-linux-gnu) Date: Thu, 14 Aug 2014 04:39:07 +0930 Message-ID: <87zjf88awc.fsf@rustcorp.com.au> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The khwrngd thread is started when a hwrng device of sufficient quality is registered. The virtio-rng device is backed by the hypervisor, and we trust the hypervisor to provide real entropy. A malicious hypervisor is a scenario that's irrelevant -- such a setup is bound to cause all sorts of badness, and a compromised hwrng is not the biggest threat. Given this, we are certain the quality of randomness we receive is perfectly trustworthy. Hence, we use 100% for the factor, indicating maximum confidence in the source. Signed-off-by: Amit Shah Signed-off-by: Rusty Russell --- Pretty small and contained patch; would be great if it is picked up for 3.17. v2: re-word commit msg [Agreed, re-sending to Linus with SOB before jumping on plane] --- drivers/char/hw_random/virtio-rng.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c index 0027137..2e3139e 100644 --- a/drivers/char/hw_random/virtio-rng.c +++ b/drivers/char/hw_random/virtio-rng.c @@ -116,6 +116,7 @@ static int probe_common(struct virtio_device *vdev) .cleanup = virtio_cleanup, .priv = (unsigned long)vi, .name = vi->name, + .quality = 1000, }; vdev->priv = vi;