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_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 DF8BFC3A59F for ; Tue, 27 Aug 2019 01:33:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A752420850 for ; Tue, 27 Aug 2019 01:33:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728527AbfH0Bd5 convert rfc822-to-8bit (ORCPT ); Mon, 26 Aug 2019 21:33:57 -0400 Received: from bilbo.ozlabs.org ([203.11.71.1]:50255 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726257AbfH0Bd5 (ORCPT ); Mon, 26 Aug 2019 21:33:57 -0400 Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 46HWcH4NZ4z9s00; Tue, 27 Aug 2019 11:33:51 +1000 (AEST) From: Michael Ellerman To: Scott Wood Cc: linux-kernel@vger.kernel.org, wangkefeng.wang@huawei.com, yebin10@huawei.com, thunder.leizhen@huawei.com, jingxiangfeng@huawei.com, fanchengyang@huawei.com, zhaohongjiang@huawei.com, Jason Yan , linuxppc-dev@lists.ozlabs.org, diana.craciun@nxp.com, christophe.leroy@c-s.fr, benh@kernel.crashing.org, paulus@samba.org, npiggin@gmail.com, keescook@chromium.org, kernel-hardening@lists.openwall.com Subject: Re: [PATCH v6 00/12] implement KASLR for powerpc/fsl_booke/32 In-Reply-To: <529fd908-42d6-f96f-daa2-9010f3035879@huawei.com> References: <20190809100800.5426-1-yanaijie@huawei.com> <529fd908-42d6-f96f-daa2-9010f3035879@huawei.com> Date: Tue, 27 Aug 2019 11:33:51 +1000 Message-ID: <878srf4cjk.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jason Yan writes: > A polite ping :) > > What else should I do now? That's a good question. Scott, are you still maintaining FSL bits, and if so any comments? Or should I take this. cheers > On 2019/8/19 14:12, Jason Yan wrote: >> Hi Michael, >> >> Is there anything more I should do to get this feature meeting the >> requirements of the mainline? >> >> Thanks, >> Jason >> >> On 2019/8/9 18:07, 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    <-----| >>> >>>                                kernstart_virt_addr >>> >>> 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. >>> >>> Changes since v5: >>>   - Rename M_IF_NEEDED to MAS2_M_IF_NEEDED >>>   - Define some global variable as __ro_after_init >>>   - Replace kimage_vaddr with kernstart_virt_addr >>>   - Depend on RELOCATABLE, not select it >>>   - Modify the comment block below the SPDX tag >>>   - Remove some useless headers in kaslr_booke.c and move is_second_reloc >>>     declarationto mmu_decl.h >>>   - Remove DBG() and use pr_debug() and rewrite comment above >>> get_boot_seed(). >>>   - Add a patch to document the KASLR implementation. >>>   - Split a patch from patch #10 which exports kaslr offset in >>> VMCOREINFO ELF notes. >>>   - Remove extra logic around finding nokaslr string in cmdline. >>>   - Make regions static global and __initdata >>> >>> Changes since v4: >>>   - Add Reviewed-by tag from Christophe >>>   - Remove an unnecessary cast >>>   - Remove unnecessary parenthesis >>>   - Fix checkpatch warning >>> >>> Changes since v3: >>>   - Add Reviewed-by and Tested-by tag from Diana >>>   - Change the comment in fsl_booke_entry_mapping.S to be consistent >>>     with the new code. >>> >>> Changes since v2: >>>   - Remove unnecessary #ifdef >>>   - Use SZ_64M instead of0x4000000 >>>   - Call early_init_dt_scan_chosen() to init boot_command_line >>>   - Rename kaslr_second_init() to kaslr_late_init() >>> >>> Changes since v1: >>>   - Remove some useless 'extern' keyword. >>>   - Replace EXPORT_SYMBOL with EXPORT_SYMBOL_GPL >>>   - Improve some assembly code >>>   - Use memzero_explicit instead of memset >>>   - Use boot_command_line and remove early_command_line >>>   - Do not print kaslr offset if kaslr is disabled >>> >>> Jason Yan (12): >>>    powerpc: unify definition of M_IF_NEEDED >>>    powerpc: move memstart_addr and kernstart_addr to init-common.c >>>    powerpc: introduce kernstart_virt_addr 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 >>>    powerpc/fsl_booke/kaslr: export offset in VMCOREINFO ELF notes >>>    powerpc/fsl_booke/32: Document KASLR implementation >>> >>>   Documentation/powerpc/kaslr-booke32.rst       |  42 ++ >>>   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          |  12 +- >>>   arch/powerpc/kernel/fsl_booke_entry_mapping.S |  27 +- >>>   arch/powerpc/kernel/head_fsl_booke.S          |  55 ++- >>>   arch/powerpc/kernel/kaslr_booke.c             | 393 ++++++++++++++++++ >>>   arch/powerpc/kernel/machine_kexec.c           |   1 + >>>   arch/powerpc/kernel/misc_64.S                 |   7 +- >>>   arch/powerpc/kernel/setup-common.c            |  20 + >>>   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                    |  11 + >>>   arch/powerpc/mm/nohash/fsl_booke.c            |   8 +- >>>   18 files changed, 572 insertions(+), 52 deletions(-) >>>   create mode 100644 Documentation/powerpc/kaslr-booke32.rst >>>   create mode 100644 arch/powerpc/kernel/kaslr_booke.c >>>