From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932552Ab3DYOoa (ORCPT ); Thu, 25 Apr 2013 10:44:30 -0400 Received: from terminus.zytor.com ([198.137.202.10]:56563 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932397Ab3DYOo3 (ORCPT ); Thu, 25 Apr 2013 10:44:29 -0400 Message-ID: <51794141.3070205@zytor.com> Date: Thu, 25 Apr 2013 07:44:17 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130311 Thunderbird/17.0.4 MIME-Version: 1.0 To: Linus Torvalds CC: "Ted Ts'o" , DJ Johnston , Linux Kernel Mailing List , "H. Peter Anvin" , stable Subject: Re: [PATCH 2/2] random: Account for entropy loss due to overwrites References: <1366777569-23192-1-git-send-email-hpa@zytor.com> <1366777569-23192-3-git-send-email-hpa@zytor.com> In-Reply-To: X-Enigmail-Version: 1.5.1 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/25/2013 07:38 AM, Linus Torvalds wrote: > This doesn't work AT ALL. You even hint at the reason why in your message. > > On Tue, Apr 23, 2013 at 9:26 PM, H. Peter Anvin wrote: >> >> As such, this conservatism seems more than justified. Note, however, >> that attempting to add one bit of entropy will never succeed; nor will >> two bits unless the pool is completely empty. These roundoff >> artifacts could be improved by using fixed-point arithmetic and adding >> some number of fractional entropy bits. > > Take a look at "add_interrupt_randomness()". Hmm.. > Right. Before July of last year add_interrupt_randomness() called add_timer_randomness() which credits up to 11 bits, but not anymore. -ESTALEBRAIN. OK, so we need to track fractional bits. -hpa