From patchwork Fri Aug 9 10:07:48 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Yan X-Patchwork-Id: 11086137 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 66FA61709 for ; Fri, 9 Aug 2019 09:52:33 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 54C6428C2B for ; Fri, 9 Aug 2019 09:52:33 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4813B28C5E; Fri, 9 Aug 2019 09:52:33 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 581B928C2B for ; Fri, 9 Aug 2019 09:52:32 +0000 (UTC) Received: (qmail 12123 invoked by uid 550); 9 Aug 2019 09:52:12 -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: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 12001 invoked from network); 9 Aug 2019 09:52:11 -0000 From: Jason Yan To: , , , , , , , , CC: , , , , , , , Jason Yan Subject: [PATCH v6 00/12] implement KASLR for powerpc/fsl_booke/32 Date: Fri, 9 Aug 2019 18:07:48 +0800 Message-ID: <20190809100800.5426-1-yanaijie@huawei.com> X-Mailer: git-send-email 2.17.2 MIME-Version: 1.0 X-Originating-IP: [10.175.124.28] X-CFilter-Loop: Reflected X-Virus-Scanned: ClamAV using ClamSMTP 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