From owner-freebsd-security@FreeBSD.ORG  Fri Jul 18 21:57:40 2014
Return-Path: <owner-freebsd-security@FreeBSD.ORG>
Delivered-To: freebsd-security@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115])
 (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits))
 (No client certificate requested)
 by hub.freebsd.org (Postfix) with ESMTPS id 5AF8B2FF
 for <freebsd-security@freebsd.org>; Fri, 18 Jul 2014 21:57:40 +0000 (UTC)
Received: from mail-qa0-x22b.google.com (mail-qa0-x22b.google.com
 [IPv6:2607:f8b0:400d:c00::22b])
 (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits))
 (Client CN "smtp.gmail.com",
 Issuer "Google Internet Authority G2" (verified OK))
 by mx1.freebsd.org (Postfix) with ESMTPS id 1D2E3238F
 for <freebsd-security@freebsd.org>; Fri, 18 Jul 2014 21:57:40 +0000 (UTC)
Received: by mail-qa0-f43.google.com with SMTP id w8so3434659qac.2
 for <freebsd-security@freebsd.org>; Fri, 18 Jul 2014 14:57:39 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113;
 h=mime-version:sender:in-reply-to:references:date:message-id:subject
 :from:to:cc:content-type;
 bh=5E3N9G7BqZHcomE/qijZ01R0N2dFXI9fr5+VgIn4C14=;
 b=OIxFfwqx06eRZfPGvVIWuQjJT39jF2g0fnfVjVlh2x/c3Ant6a8sidOvG1ioSQSUNe
 x/gPk1h65wg7D57/jkYWJ1HMOLfHxqc99Gt0eC2tbwgaDF5cih02pP0+CEw47oAmugY0
 uHGuGRSW/ytY28pnn7M3oekk4g2nZy/uP43L4k26iYDSTJKoL1do+yNLalc4nP0OcEZX
 qz7AKA+v7gROhyBEWyOTFN0JivUTzHkuc/3oBQCdAriiKWaphkkei/nCgrGYKTZ1tf1M
 EJYvQtrD9oNx1hZd4Cn4crV6bnstOzwUruA7GZc5C7fDDUlqKuhhTev7lp2RpHkib4FI
 A4PQ==
MIME-Version: 1.0
X-Received: by 10.224.129.130 with SMTP id o2mr13544580qas.64.1405720659199;
 Fri, 18 Jul 2014 14:57:39 -0700 (PDT)
Sender: benlaurie@gmail.com
Received: by 10.96.222.168 with HTTP; Fri, 18 Jul 2014 14:57:39 -0700 (PDT)
In-Reply-To: <53C85F42.1000704@pyro.eu.org>
References: <53C85F42.1000704@pyro.eu.org>
Date: Fri, 18 Jul 2014 22:57:39 +0100
X-Google-Sender-Auth: 1CkjCmnG2gk8COXnUTFN1UCkT5I
Message-ID: <CAG5KPzxVaTEmDq9F9BFGQGWTGGWKZ7kZhgkPQTZ3c2-iWmcZzw@mail.gmail.com>
Subject: Re: Speed and security of /dev/urandom
From: Ben Laurie <benl@freebsd.org>
To: Steven Chamberlain <steven@pyro.eu.org>
Content-Type: text/plain; charset=UTF-8
Cc: "freebsd-security@freebsd.org security" <freebsd-security@freebsd.org>
X-BeenThere: freebsd-security@freebsd.org
X-Mailman-Version: 2.1.18
Precedence: list
List-Id: "Security issues \[members-only posting\]"
 <freebsd-security.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/freebsd-security>, 
 <mailto:freebsd-security-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-security/>
List-Post: <mailto:freebsd-security@freebsd.org>
List-Help: <mailto:freebsd-security-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-security>, 
 <mailto:freebsd-security-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Fri, 18 Jul 2014 21:57:40 -0000

On 18 July 2014 00:41, Steven Chamberlain <steven@pyro.eu.org> wrote:
> So I wonder, could a simplified arc4random for FreeBSD use Yarrow
> directly, to avoid making any of these sorts of mistakes we've seen?

Discovering that its OK to use this mechanism seems as vulnerable to
mistakes as the mistakes we've seen. I don't have good suggestions on
how to fix this.