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 3001BC7618B for ; Fri, 26 Jul 2019 07:26:40 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 8B39822BE8 for ; Fri, 26 Jul 2019 07:26:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8B39822BE8 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-16592-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 27975 invoked by uid 550); 26 Jul 2019 07:26:33 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Received: (qmail 27937 invoked from network); 26 Jul 2019 07:26:32 -0000 Subject: Re: [RFC PATCH 00/10] implement KASLR for powerpc/fsl_booke/32 To: Diana Madalina Craciun , "mpe@ellerman.id.au" , "linuxppc-dev@lists.ozlabs.org" , "christophe.leroy@c-s.fr" , "benh@kernel.crashing.org" , "paulus@samba.org" , "npiggin@gmail.com" , "keescook@chromium.org" , "kernel-hardening@lists.openwall.com" CC: "linux-kernel@vger.kernel.org" , "wangkefeng.wang@huawei.com" , "yebin10@huawei.com" , "thunder.leizhen@huawei.com" , "jingxiangfeng@huawei.com" , "fanchengyang@huawei.com" , Laurentiu Tudor References: <20190717080621.40424-1-yanaijie@huawei.com> From: Jason Yan Message-ID: Date: Fri, 26 Jul 2019 15:26:12 +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: 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 On 2019/7/26 15:04, Diana Madalina Craciun wrote: > Hi Jason, > > I have briefly tested yesterday on a P4080 board and did not see any > issues. I do not have much expertise on KASLR, but I will take a look > over the code. > Hi Diana, thanks. Looking forward to your suggestions. > Regards, > Diana > > On 7/25/2019 10:16 AM, Jason Yan wrote: >> 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 >>> >> > > > . >