From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:50251) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hMf6L-0007T6-BV for qemu-devel@nongnu.org; Fri, 03 May 2019 16:48:14 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hMf6J-0003rt-Gd for qemu-devel@nongnu.org; Fri, 03 May 2019 16:48:13 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51238) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hMf6J-0003pM-BP for qemu-devel@nongnu.org; Fri, 03 May 2019 16:48:11 -0400 Date: Fri, 3 May 2019 22:47:57 +0200 From: Kashyap Chamarthy Message-ID: <20190503204757.GF4675@paraplu> References: <20190503154613.4192-1-kchamart@redhat.com> <20190503154613.4192-2-kchamart@redhat.com> <20190503154905.GJ17905@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20190503154905.GJ17905@redhat.com> Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH] VirtIO-RNG: Update default entropy source to `/dev/urandom` List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Daniel =?iso-8859-1?Q?P=2E_Berrang=E9?= Cc: qemu-devel@nongnu.org, amit@kernel.org, armbru@redhat.com, rjones@redhat.com, peter.maydell@linaro.org On Fri, May 03, 2019 at 04:49:05PM +0100, Daniel P. Berrang=E9 wrote: > On Fri, May 03, 2019 at 05:46:13PM +0200, Kashyap Chamarthy wrote: > > When QEMU exposes a VirtIO-RNG device to the guest, that device needs= a > > source of entropy, and that source needs to be "non-blocking", like > > `/dev/urandom`. However, currently QEMU defaults to the problematic > > `/dev/random`, which is "blocking" (as in, it waits until sufficient > > entropy is available). > >=20 > > So change the entropy source to the recommended `/dev/urandom`. > >=20 > > Related discussion in these[1][2] past threads. > >=20 > > [1] https://lists.nongnu.org/archive/html/qemu-devel/2018-06/msg08335= .html > > -- "RNG: Any reason QEMU doesn't default to `/dev/urandom`?" > > [2] https://lists.nongnu.org/archive/html/qemu-devel/2018-09/msg02724= .html > > -- "[RFC] Virtio RNG: Consider changing the default entropy sourc= e to > > /dev/urandom" > >=20 > > Signed-off-by: Kashyap Chamarthy > > --- > > backends/rng-random.c | 2 +- > > qemu-options.hx | 2 +- > > 2 files changed, 2 insertions(+), 2 deletions(-) >=20 > Reviewed-by: Daniel P. Berrang=E9 I'm wondering if this needs to be mentioned on a Release Notes wiki somewhere -- because we're changing the default. --=20 /kashyap From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.4 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7A2E1C43219 for ; Fri, 3 May 2019 20:49:09 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 4CF772081C for ; Fri, 3 May 2019 20:49:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4CF772081C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([127.0.0.1]:47093 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hMf7E-0007lm-CT for qemu-devel@archiver.kernel.org; Fri, 03 May 2019 16:49:08 -0400 Received: from eggs.gnu.org ([209.51.188.92]:50251) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hMf6L-0007T6-BV for qemu-devel@nongnu.org; Fri, 03 May 2019 16:48:14 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hMf6J-0003rt-Gd for qemu-devel@nongnu.org; Fri, 03 May 2019 16:48:13 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51238) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hMf6J-0003pM-BP for qemu-devel@nongnu.org; Fri, 03 May 2019 16:48:11 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 05EFF2DD43; Fri, 3 May 2019 20:48:02 +0000 (UTC) Received: from paraplu.localdomain (ovpn-116-28.ams2.redhat.com [10.36.116.28]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 7D48E600C7; Fri, 3 May 2019 20:48:01 +0000 (UTC) Received: by paraplu.localdomain (Postfix, from userid 1001) id E678F3E0219; Fri, 3 May 2019 22:47:57 +0200 (CEST) Date: Fri, 3 May 2019 22:47:57 +0200 From: Kashyap Chamarthy To: Daniel =?iso-8859-1?Q?P=2E_Berrang=E9?= Message-ID: <20190503204757.GF4675@paraplu> References: <20190503154613.4192-1-kchamart@redhat.com> <20190503154613.4192-2-kchamart@redhat.com> <20190503154905.GJ17905@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline In-Reply-To: <20190503154905.GJ17905@redhat.com> User-Agent: Mutt/1.11.3 (2019-02-01) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Fri, 03 May 2019 20:48:02 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH] VirtIO-RNG: Update default entropy source to `/dev/urandom` X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: peter.maydell@linaro.org, armbru@redhat.com, rjones@redhat.com, qemu-devel@nongnu.org, amit@kernel.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Message-ID: <20190503204757.JLJX-3DbbKT0NumauFycq2RhJAolbzw2mhQZupqWTDY@z> On Fri, May 03, 2019 at 04:49:05PM +0100, Daniel P. Berrang=E9 wrote: > On Fri, May 03, 2019 at 05:46:13PM +0200, Kashyap Chamarthy wrote: > > When QEMU exposes a VirtIO-RNG device to the guest, that device needs= a > > source of entropy, and that source needs to be "non-blocking", like > > `/dev/urandom`. However, currently QEMU defaults to the problematic > > `/dev/random`, which is "blocking" (as in, it waits until sufficient > > entropy is available). > >=20 > > So change the entropy source to the recommended `/dev/urandom`. > >=20 > > Related discussion in these[1][2] past threads. > >=20 > > [1] https://lists.nongnu.org/archive/html/qemu-devel/2018-06/msg08335= .html > > -- "RNG: Any reason QEMU doesn't default to `/dev/urandom`?" > > [2] https://lists.nongnu.org/archive/html/qemu-devel/2018-09/msg02724= .html > > -- "[RFC] Virtio RNG: Consider changing the default entropy sourc= e to > > /dev/urandom" > >=20 > > Signed-off-by: Kashyap Chamarthy > > --- > > backends/rng-random.c | 2 +- > > qemu-options.hx | 2 +- > > 2 files changed, 2 insertions(+), 2 deletions(-) >=20 > Reviewed-by: Daniel P. Berrang=E9 I'm wondering if this needs to be mentioned on a Release Notes wiki somewhere -- because we're changing the default. --=20 /kashyap