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 2A3DBC3A59B for ; Mon, 19 Aug 2019 06:12:47 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 55E9A2087E for ; Mon, 19 Aug 2019 06:12:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 55E9A2087E 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-16793-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 1283 invoked by uid 550); 19 Aug 2019 06:12:36 -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 1242 invoked from network); 19 Aug 2019 06:12:35 -0000 Subject: Re: [PATCH v6 00/12] implement KASLR for powerpc/fsl_booke/32 To: , , , , , , , , CC: , , , , , , References: <20190809100800.5426-1-yanaijie@huawei.com> From: Jason Yan Message-ID: Date: Mon, 19 Aug 2019 14:12:09 +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: <20190809100800.5426-1-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 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 >