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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 AEF5BECDE5F for ; Mon, 23 Jul 2018 11:50:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6F2AD20854 for ; Mon, 23 Jul 2018 11:50:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6F2AD20854 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388131AbeGWMvG (ORCPT ); Mon, 23 Jul 2018 08:51:06 -0400 Received: from mx2.suse.de ([195.135.220.15]:35902 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2387842AbeGWMvG (ORCPT ); Mon, 23 Jul 2018 08:51:06 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id C211FAFC8; Mon, 23 Jul 2018 11:50:13 +0000 (UTC) Message-ID: <1532346156.3057.11.camel@suse.com> Subject: Re: [PATCH 0/4][RFC v2] Introduce the in-kernel hibernation encryption From: Oliver Neukum To: Pavel Machek , Yu Chen Cc: "Rafael J . Wysocki" , Eric Biggers , "Lee, Chun-Yi" , Theodore Ts o , Stephan Mueller , Denis Kenzior , linux-pm@vger.kernel.org, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, "Gu, Kookoo" , "Zhang, Rui" Date: Mon, 23 Jul 2018 13:42:36 +0200 In-Reply-To: <20180720102532.GA20284@amd> References: <20180718202235.GA4132@amd> <20180718235851.GA22170@sandybridge-desktop> <20180719110149.GA4679@amd> <20180719132003.GA30981@sandybridge-desktop> <20180720102532.GA20284@amd> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.26.6 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fr, 2018-07-20 at 12:25 +0200, Pavel Machek wrote: > Hi! Hello, > > Let me paste the log here: > > > > 1. (This is not to compare with uswsusp but other > > tools) One advantage is: Users do not have to > > encrypt the whole swap partition as other tools. > > Well.. encrypting the partition seems like good idea anyway. Yes, but it is a policy decision the kernel should not force. STD needs to work anyway. > > 2. Ideally kernel memory should be encrypted by the > > kernel itself. We have uswsusp to support user > > space hibernation, however doing the encryption > > in kernel space has more advantages: > > 2.1 Not having to transfer plain text kernel memory to > > user space. Per Lee, Chun-Yi, uswsusp is disabled > > when the kernel is locked down: > > https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/ > > linux-fs.git/commit/?h=lockdown-20180410& > > id=8732c1663d7c0305ae01ba5a1ee4d2299b7b4612 > > due to: > > "There have some functions be locked-down because > > there have no appropriate mechanisms to check the > > integrity of writing data." > > https://patchwork.kernel.org/patch/10476751/ > > So your goal is to make hibernation compatible with kernel > lockdown? Do your patches provide sufficient security that hibernation > can be enabled with kernel lockdown? OK, maybe I am dense, but if the key comes from user space, will that be enough? > > 2.2 Not having to copy each page to user space > > one by one not in parallel, which might introduce > > significant amount of copy_to_user() and it might > > not be efficient on servers having large amount of DRAM. > > So how big speedup can be attributed by not doing copy_to_user? That would be an argument for compression in kernel space. Not encrpting would always be faster. > > 2.3 Distribution has requirement to do snapshot > > signature for verification, which can be built > > by leveraging this patch set. > > Signatures can be done by uswsusp, too, right? Not if you want to keep the chain of trust intact. User space is not signed. > > 2.4 The encryption is in the kernel, so it doesn't > > have to worry too much about bugs in user space > > utilities and similar, for example. > > Answer to bugs in userspace is _not_ to move code from userspace to kernel. Indeed. > > Joey Lee and I had a discussion on his previous work at > > https://patchwork.kernel.org/patch/10476751 > > We collaborate on this task and his snapshot signature > > feature can be based on this patch set. > > Well, his work can also work without your patchset, right? Yes. But you are objecting to encryption in kernel space at all, aren't you? Regards Oliver