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=-2.2 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 5AE74C7618B for ; Thu, 25 Jul 2019 07:16:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2476421734 for ; Thu, 25 Jul 2019 07:16:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387839AbfGYHQk (ORCPT ); Thu, 25 Jul 2019 03:16:40 -0400 Received: from szxga04-in.huawei.com ([45.249.212.190]:2721 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2387776AbfGYHQj (ORCPT ); Thu, 25 Jul 2019 03:16:39 -0400 Received: from DGGEMS406-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id 6D97166E45FB2AA639F1; Thu, 25 Jul 2019 15:16:37 +0800 (CST) Received: from [127.0.0.1] (10.177.96.203) by DGGEMS406-HUB.china.huawei.com (10.3.19.206) with Microsoft SMTP Server id 14.3.439.0; Thu, 25 Jul 2019 15:16:30 +0800 Subject: Re: [RFC PATCH 00/10] implement KASLR for powerpc/fsl_booke/32 To: , , , , , , , , CC: , , , , , References: <20190717080621.40424-1-yanaijie@huawei.com> From: Jason Yan Message-ID: Date: Thu, 25 Jul 2019 15:16:28 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.5.0 MIME-Version: 1.0 In-Reply-To: <20190717080621.40424-1-yanaijie@huawei.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.96.203] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi all, any comments? On 2019/7/17 16:06, Jason Yan wrote: > This series implements KASLR for powerpc/fsl_booke/32, as a security > feature that deters exploit attempts relying on knowledge of the location > of kernel internals. > > Since CONFIG_RELOCATABLE has already supported, what we need to do is > map or copy kernel to a proper place and relocate. Freescale Book-E > parts expect lowmem to be mapped by fixed TLB entries(TLB1). The TLB1 > entries are not suitable to map the kernel directly in a randomized > region, so we chose to copy the kernel to a proper place and restart to > relocate. > > Entropy is derived from the banner and timer base, which will change every > build and boot. This not so much safe so additionally the bootloader may > pass entropy via the /chosen/kaslr-seed node in device tree. > > We will use the first 512M of the low memory to randomize the kernel > image. The memory will be split in 64M zones. We will use the lower 8 > bit of the entropy to decide the index of the 64M zone. Then we chose a > 16K aligned offset inside the 64M zone to put the kernel in. > > KERNELBASE > > |--> 64M <--| > | | > +---------------+ +----------------+---------------+ > | |....| |kernel| | | > +---------------+ +----------------+---------------+ > | | > |-----> offset <-----| > > kimage_vaddr > > We also check if we will overlap with some areas like the dtb area, the > initrd area or the crashkernel area. If we cannot find a proper area, > kaslr will be disabled and boot from the original kernel. > > Jason Yan (10): > powerpc: unify definition of M_IF_NEEDED > powerpc: move memstart_addr and kernstart_addr to init-common.c > powerpc: introduce kimage_vaddr to store the kernel base > powerpc/fsl_booke/32: introduce create_tlb_entry() helper > powerpc/fsl_booke/32: introduce reloc_kernel_entry() helper > powerpc/fsl_booke/32: implement KASLR infrastructure > powerpc/fsl_booke/32: randomize the kernel image offset > powerpc/fsl_booke/kaslr: clear the original kernel if randomized > powerpc/fsl_booke/kaslr: support nokaslr cmdline parameter > powerpc/fsl_booke/kaslr: dump out kernel offset information on panic > > arch/powerpc/Kconfig | 11 + > arch/powerpc/include/asm/nohash/mmu-book3e.h | 10 + > arch/powerpc/include/asm/page.h | 7 + > arch/powerpc/kernel/Makefile | 1 + > arch/powerpc/kernel/early_32.c | 2 +- > arch/powerpc/kernel/exceptions-64e.S | 10 - > arch/powerpc/kernel/fsl_booke_entry_mapping.S | 23 +- > arch/powerpc/kernel/head_fsl_booke.S | 61 ++- > arch/powerpc/kernel/kaslr_booke.c | 439 ++++++++++++++++++ > arch/powerpc/kernel/machine_kexec.c | 1 + > arch/powerpc/kernel/misc_64.S | 5 - > arch/powerpc/kernel/setup-common.c | 23 + > arch/powerpc/mm/init-common.c | 7 + > arch/powerpc/mm/init_32.c | 5 - > arch/powerpc/mm/init_64.c | 5 - > arch/powerpc/mm/mmu_decl.h | 10 + > arch/powerpc/mm/nohash/fsl_booke.c | 8 +- > 17 files changed, 580 insertions(+), 48 deletions(-) > create mode 100644 arch/powerpc/kernel/kaslr_booke.c >