From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752643AbdFVDUh (ORCPT ); Wed, 21 Jun 2017 23:20:37 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44058 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752171AbdFVDUg (ORCPT ); Wed, 21 Jun 2017 23:20:36 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 91826C04D2AC Authentication-Results: ext-mx07.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx07.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=bhe@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 91826C04D2AC Date: Thu, 22 Jun 2017 11:20:32 +0800 From: Baoquan He To: Chao Fan Cc: linux-kernel@vger.kernel.org, keescook@chromium.org, x86@kernel.org, caoj.fnst@cn.fujitsu.com, douly.fnst@cn.fujitsu.com Subject: Re: [RFC][PATCH 0/2] x86/boot/KASLR: Restrict kernel to be randomized in mirror regions if existed Message-ID: <20170622032032.GA9794@x1> References: <1497513169-25283-1-git-send-email-bhe@redhat.com> <20170622031034.GE30941@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170622031034.GE30941@localhost.localdomain> User-Agent: Mutt/1.7.0 (2016-08-17) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Thu, 22 Jun 2017 03:20:35 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/22/17 at 11:10am, Chao Fan wrote: > Hi all, > > After testing this issue for 100 times in total, I think this patchset > works well. Thanks for your effort, Chao! Then I will repost with some modification according to the kbuild test report and your comment, and thanks again for that. Maybe next week, there is urgent rhel bug now I am trying to fix. Thanks Baoquan > > The size of physical memory in my test machine is 229G, the size of > mirror region is 26G. In the 100 times, 50 times are with this patchset, > 50 times are without it. > > Here is my test result: > > ------------------------------------------------ > |total times|in non-mirror|in mirror > ------------|-----------|-------------|--------- > before patch| 50 | 41 | 9 > ------------|-----------|-------------|--------- > with patch | 50 | 0 | 50 > ------------------------------------------------ > > Firstly, I add the earlyprintk to get efi map when walking the efi map. > Then get the range of mirror regions. > In kaslr.c, add the earlyprintk to get random_addr in function > choose_random_location, find_random_phys_addr. Then check if the address > in which is choosen to extract kernel is in mirror region. > > If there are any problems, please let me know. > > Thanks, > Chao Fan > > On Thu, Jun 15, 2017 at 03:52:47PM +0800, Baoquan He wrote: > >Our customer reported that Kernel text may be located on non-mirror > >region (movable zone) when both address range mirroring feature and > >KASLR are enabled. > > > >The functions of address range mirroring feature are as follows. > >- The physical memory region whose descriptors in EFI memory map have > > EFI_MEMORY_MORE_RELIABLE attribute (bit: 16) are mirrored > >- The function arranges such mirror region into normal zone and other region > > into movable zone in order to locate kernel code and data on mirror region > > > >So we need restrict kernel to be located inside mirror region if it > >is existed. > > > >The method is very simple. If efi is enabled, just iterate all efi > >memory map and pick up mirror region to process for adding candidate > >of slot. If efi disabled or no mirror region existed, still process > >e820 memory map. This won't bring much efficiency loss, at worst we > >just go through all efi memory maps and found no mirror. > > > >One question: > >From code, though mirror regions are existed, they are meaningful only > >if kernelcore=mirror kernel option is specified. Not sure if my understanding > >is correct. > > > >NOTE: > >I haven't got a machine with efi mirror region enabled, so only test the > >e820 map processing case and the case of no mirror region on efi machine. > >So set this as a RFC patchset, will post formal one after above question > >is made clear and mirror issue test passed. > > > >Baoquan He (2): > > x86/boot/KASLR: Adapt process_e820_entry for all kinds of memory map > > x86/boot/KASLR: Restrict kernel to be randomized in mirror regions if > > existed > > > > arch/x86/boot/compressed/kaslr.c | 129 +++++++++++++++++++++++++++++++-------- > > 1 file changed, 104 insertions(+), 25 deletions(-) > > > >-- > >2.5.5 > > > > > > > >