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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 A4BC2C4BA0A for ; Wed, 26 Feb 2020 08:18:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7D7D22084E for ; Wed, 26 Feb 2020 08:18:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727709AbgBZISq (ORCPT ); Wed, 26 Feb 2020 03:18:46 -0500 Received: from szxga06-in.huawei.com ([45.249.212.32]:43254 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727247AbgBZISp (ORCPT ); Wed, 26 Feb 2020 03:18:45 -0500 Received: from DGGEMS404-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 4AFED4A428E75A358071; Wed, 26 Feb 2020 16:18:37 +0800 (CST) Received: from [127.0.0.1] (10.173.221.195) by DGGEMS404-HUB.china.huawei.com (10.3.19.204) with Microsoft SMTP Server id 14.3.439.0; Wed, 26 Feb 2020 16:18:29 +0800 Subject: Re: [PATCH v3 0/6] implement KASLR for powerpc/fsl_booke/64 To: Daniel Axtens , , , , , , , , , , CC: , References: <20200206025825.22934-1-yanaijie@huawei.com> <87tv3drf79.fsf@dja-thinkpad.axtens.net> From: Jason Yan Message-ID: <8171d326-5138-4f5c-cff6-ad3ee606f0c2@huawei.com> Date: Wed, 26 Feb 2020 16:18:27 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.4.2 MIME-Version: 1.0 In-Reply-To: <87tv3drf79.fsf@dja-thinkpad.axtens.net> Content-Type: text/plain; charset="gbk"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.173.221.195] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Daniel, ÔÚ 2020/2/26 15:16, Daniel Axtens дµÀ: > Hi Jason, > >> This is a try to implement KASLR for Freescale BookE64 which is based on >> my earlier implementation for Freescale BookE32: >> https://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=131718 >> >> The implementation for Freescale BookE64 is similar as BookE32. One >> difference is that Freescale BookE64 set up a TLB mapping of 1G during >> booting. Another difference is that ppc64 needs the kernel to be >> 64K-aligned. So we can randomize the kernel in this 1G mapping and make >> it 64K-aligned. This can save some code to creat another TLB map at >> early boot. The disadvantage is that we only have about 1G/64K = 16384 >> slots to put the kernel in. >> >> KERNELBASE >> >> 64K |--> kernel <--| >> | | | >> +--+--+--+ +--+--+--+--+--+--+--+--+--+ +--+--+ >> | | | |....| | | | | | | | | |....| | | >> +--+--+--+ +--+--+--+--+--+--+--+--+--+ +--+--+ >> | | 1G >> |-----> offset <-----| >> >> kernstart_virt_addr >> >> I'm not sure if the slot numbers is enough or the design has any >> defects. If you have some better ideas, I would be happy to hear that. >> >> Thank you all. >> > > Are you making any attempt to hide kernel address leaks in this series? Yes. > I've just been looking at the stackdump code just now, and it directly > prints link registers and stack pointers, which is probably enough to > determine the kernel base address: > > SPs: LRs: %pS pointer > [ 0.424506] [c0000000de403970] [c000000001fc0458] dump_stack+0xfc/0x154 (unreliable) > [ 0.424593] [c0000000de4039c0] [c000000000267eec] panic+0x258/0x5ac > [ 0.424659] [c0000000de403a60] [c0000000024d7a00] mount_block_root+0x634/0x7c0 > [ 0.424734] [c0000000de403be0] [c0000000024d8100] prepare_namespace+0x1ec/0x23c > [ 0.424811] [c0000000de403c60] [c0000000024d7010] kernel_init_freeable+0x804/0x880 > > git grep \\\"REG\\\" arch/powerpc shows a few other uses like this, all > in process.c or in xmon. > Thanks for reminding this. > Maybe replacing the REG format string in KASLR mode would be sufficient? > Most archs have removed the address printing when dumping stack. Do we really have to print this? If we have to do this, maybe we can use "%pK" so that they will be hidden from unprivileged users. Thanks, Jason > Regards, > Daniel > > >> v2->v3: >> Fix build error when KASLR is disabled. >> v1->v2: >> Add __kaslr_offset for the secondary cpu boot up. >> >> Jason Yan (6): >> powerpc/fsl_booke/kaslr: refactor kaslr_legal_offset() and >> kaslr_early_init() >> powerpc/fsl_booke/64: introduce reloc_kernel_entry() helper >> powerpc/fsl_booke/64: implement KASLR for fsl_booke64 >> powerpc/fsl_booke/64: do not clear the BSS for the second pass >> powerpc/fsl_booke/64: clear the original kernel if randomized >> powerpc/fsl_booke/kaslr: rename kaslr-booke32.rst to kaslr-booke.rst >> and add 64bit part >> >> .../{kaslr-booke32.rst => kaslr-booke.rst} | 35 +++++++-- >> arch/powerpc/Kconfig | 2 +- >> arch/powerpc/kernel/exceptions-64e.S | 23 ++++++ >> arch/powerpc/kernel/head_64.S | 14 ++++ >> arch/powerpc/kernel/setup_64.c | 4 +- >> arch/powerpc/mm/mmu_decl.h | 19 ++--- >> arch/powerpc/mm/nohash/kaslr_booke.c | 71 +++++++++++++------ >> 7 files changed, 132 insertions(+), 36 deletions(-) >> rename Documentation/powerpc/{kaslr-booke32.rst => kaslr-booke.rst} (59%) >> >> -- >> 2.17.2 > > . > 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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 F1FDDC4BA0B for ; Wed, 26 Feb 2020 08:20:40 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A747D20714 for ; Wed, 26 Feb 2020 08:20:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A747D20714 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 48S7z66CgSzDqn5 for ; Wed, 26 Feb 2020 19:20:34 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=huawei.com (client-ip=45.249.212.32; helo=huawei.com; envelope-from=yanaijie@huawei.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=huawei.com Received: from huawei.com (szxga06-in.huawei.com [45.249.212.32]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 48S7xH0H3qzDqjc for ; Wed, 26 Feb 2020 19:18:59 +1100 (AEDT) Received: from DGGEMS404-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 4AFED4A428E75A358071; Wed, 26 Feb 2020 16:18:37 +0800 (CST) Received: from [127.0.0.1] (10.173.221.195) by DGGEMS404-HUB.china.huawei.com (10.3.19.204) with Microsoft SMTP Server id 14.3.439.0; Wed, 26 Feb 2020 16:18:29 +0800 Subject: Re: [PATCH v3 0/6] implement KASLR for powerpc/fsl_booke/64 To: Daniel Axtens , , , , , , , , , , References: <20200206025825.22934-1-yanaijie@huawei.com> <87tv3drf79.fsf@dja-thinkpad.axtens.net> From: Jason Yan Message-ID: <8171d326-5138-4f5c-cff6-ad3ee606f0c2@huawei.com> Date: Wed, 26 Feb 2020 16:18:27 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.4.2 MIME-Version: 1.0 In-Reply-To: <87tv3drf79.fsf@dja-thinkpad.axtens.net> Content-Type: text/plain; charset="gbk"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.173.221.195] X-CFilter-Loop: Reflected X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-kernel@vger.kernel.org, zhaohongjiang@huawei.com Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Hi Daniel, ÔÚ 2020/2/26 15:16, Daniel Axtens дµÀ: > Hi Jason, > >> This is a try to implement KASLR for Freescale BookE64 which is based on >> my earlier implementation for Freescale BookE32: >> https://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=131718 >> >> The implementation for Freescale BookE64 is similar as BookE32. One >> difference is that Freescale BookE64 set up a TLB mapping of 1G during >> booting. Another difference is that ppc64 needs the kernel to be >> 64K-aligned. So we can randomize the kernel in this 1G mapping and make >> it 64K-aligned. This can save some code to creat another TLB map at >> early boot. The disadvantage is that we only have about 1G/64K = 16384 >> slots to put the kernel in. >> >> KERNELBASE >> >> 64K |--> kernel <--| >> | | | >> +--+--+--+ +--+--+--+--+--+--+--+--+--+ +--+--+ >> | | | |....| | | | | | | | | |....| | | >> +--+--+--+ +--+--+--+--+--+--+--+--+--+ +--+--+ >> | | 1G >> |-----> offset <-----| >> >> kernstart_virt_addr >> >> I'm not sure if the slot numbers is enough or the design has any >> defects. If you have some better ideas, I would be happy to hear that. >> >> Thank you all. >> > > Are you making any attempt to hide kernel address leaks in this series? Yes. > I've just been looking at the stackdump code just now, and it directly > prints link registers and stack pointers, which is probably enough to > determine the kernel base address: > > SPs: LRs: %pS pointer > [ 0.424506] [c0000000de403970] [c000000001fc0458] dump_stack+0xfc/0x154 (unreliable) > [ 0.424593] [c0000000de4039c0] [c000000000267eec] panic+0x258/0x5ac > [ 0.424659] [c0000000de403a60] [c0000000024d7a00] mount_block_root+0x634/0x7c0 > [ 0.424734] [c0000000de403be0] [c0000000024d8100] prepare_namespace+0x1ec/0x23c > [ 0.424811] [c0000000de403c60] [c0000000024d7010] kernel_init_freeable+0x804/0x880 > > git grep \\\"REG\\\" arch/powerpc shows a few other uses like this, all > in process.c or in xmon. > Thanks for reminding this. > Maybe replacing the REG format string in KASLR mode would be sufficient? > Most archs have removed the address printing when dumping stack. Do we really have to print this? If we have to do this, maybe we can use "%pK" so that they will be hidden from unprivileged users. Thanks, Jason > Regards, > Daniel > > >> v2->v3: >> Fix build error when KASLR is disabled. >> v1->v2: >> Add __kaslr_offset for the secondary cpu boot up. >> >> Jason Yan (6): >> powerpc/fsl_booke/kaslr: refactor kaslr_legal_offset() and >> kaslr_early_init() >> powerpc/fsl_booke/64: introduce reloc_kernel_entry() helper >> powerpc/fsl_booke/64: implement KASLR for fsl_booke64 >> powerpc/fsl_booke/64: do not clear the BSS for the second pass >> powerpc/fsl_booke/64: clear the original kernel if randomized >> powerpc/fsl_booke/kaslr: rename kaslr-booke32.rst to kaslr-booke.rst >> and add 64bit part >> >> .../{kaslr-booke32.rst => kaslr-booke.rst} | 35 +++++++-- >> arch/powerpc/Kconfig | 2 +- >> arch/powerpc/kernel/exceptions-64e.S | 23 ++++++ >> arch/powerpc/kernel/head_64.S | 14 ++++ >> arch/powerpc/kernel/setup_64.c | 4 +- >> arch/powerpc/mm/mmu_decl.h | 19 ++--- >> arch/powerpc/mm/nohash/kaslr_booke.c | 71 +++++++++++++------ >> 7 files changed, 132 insertions(+), 36 deletions(-) >> rename Documentation/powerpc/{kaslr-booke32.rst => kaslr-booke.rst} (59%) >> >> -- >> 2.17.2 > > . >