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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 726A5C32792 for ; Mon, 30 Sep 2019 20:47:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3BA1C224FE for ; Mon, 30 Sep 2019 20:47:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="NmmtdnRN" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729415AbfI3Urm (ORCPT ); Mon, 30 Sep 2019 16:47:42 -0400 Received: from mail-io1-f49.google.com ([209.85.166.49]:33119 "EHLO mail-io1-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726425AbfI3Urm (ORCPT ); Mon, 30 Sep 2019 16:47:42 -0400 Received: by mail-io1-f49.google.com with SMTP id z19so42109170ior.0 for ; Mon, 30 Sep 2019 13:47:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=xVE7UhrvOn/gSJ8sR6VSbxHfHmyx3hbL0Hq7OBVF+qs=; b=NmmtdnRNpJGvs1EGQkSFVydi8Yfuu/G4fbedduH4jOUM+zUpCagbcZBWf9xrOtvHJ2 838PUD1dxGSbZDAIShIumwHq3Pi3JlqBuyWDv7Is2VuNrP7mD5jWfjwKP++YOzvEQGpI m9WG5M1zzY5L+HPTxS8Di+i1ecZqpAkUFWkb8= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=xVE7UhrvOn/gSJ8sR6VSbxHfHmyx3hbL0Hq7OBVF+qs=; b=P6+sS6zVWdyd6phi09wqUqyHbcog0dssO8phHSdEtJsybeW5VAAVTntqVC53JY0iB4 frvPuTNu01mXPRli0oj2rurjbD6Qe8rXAQxPH++iE+fpIZD6MdNgQ3ank6Su1Izab6Mu bcJaJXpxY4B28C8BILim0yf4R166FCtez9CvE05dYNwzNVAcfcy44RSFjO52drVb7GA8 Ix+P8urWiCYEBIGQS4WgU6zfN0gui+Z9xdFnAo0rxLXxJQ4DYCZUGtM46BqPAQ0w2L7s DJbz4KdHKDDR+dNBblMsvB0xWErj5vbXyC1A8bA9VJfPjFKSsgZFra62beEnO5eiqJSt xetA== X-Gm-Message-State: APjAAAUxYjjdSW/LJ5yAN/9AKBARA8owPS0R0MSw4nTs2bsR82w8zZc7 wFMpoGWeB5fcPr76KkwQHPk2pqnkgk8= X-Google-Smtp-Source: APXvYqzt8KCP+v3EQ6jxpJhI/Ik/ikaaZvJfTSFfX3rpR4ycYZhpUDVrE0XihtpcoeJ5Gm87okLXhg== X-Received: by 2002:a63:2301:: with SMTP id j1mr25533599pgj.411.1569866722202; Mon, 30 Sep 2019 11:05:22 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id h1sm13176567pfk.124.2019.09.30.11.05.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 30 Sep 2019 11:05:21 -0700 (PDT) Date: Mon, 30 Sep 2019 11:05:20 -0700 From: Kees Cook To: Borislav Petkov Cc: Linus Torvalds , Thomas Gleixner , "Ahmed S. Darwish" , LKML , Theodore Ts'o , Nicholas Mc Guire , the arch/x86 maintainers , Andy Lutomirski Subject: Re: x86/random: Speculation to the rescue Message-ID: <201909301054.4E4F12B6D7@keescook> References: <20190930061014.GC29694@zn.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190930061014.GC29694@zn.tnic> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 30, 2019 at 08:10:15AM +0200, Borislav Petkov wrote: > On Sun, Sep 29, 2019 at 07:59:19PM -0700, Linus Torvalds wrote: > > All my smoke testing looked fine - I disabled trusting the CPU, I > > increased the required entropy a lot, and to actually trigger the > > lockup issue without the broken user space, I made /dev/urandom do > > that "wait for entropy" thing too. > > Hohum, seems to get rid of the longish delay during boot on my test > boxes here: Yes; for me too. This makes a huge difference in my ARM emulation environments (where I wasn't using virtio-rng-device). Those VMs were very boot entropy starved -- I was waiting minutes for sshd to start. I doubt running something like dieharder on urandom would actually show any deficiencies, but I've started a test up anyway. I'll yell in a few hours if it actually has something bad to say. :) -- Kees Cook