From: Jason Yan <yanaijie@huawei.com>
To: <mpe@ellerman.id.au>, <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>
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>
Subject: Re: [PATCH v6 00/12] implement KASLR for powerpc/fsl_booke/32
Date: Mon, 19 Aug 2019 14:12:09 +0800 [thread overview]
Message-ID: <ed96199d-715c-3f1c-39db-10a569ba6601@huawei.com> (raw)
In-Reply-To: <20190809100800.5426-1-yanaijie@huawei.com>
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
>
next prev parent reply other threads:[~2019-08-19 6:12 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-09 10:07 [PATCH v6 00/12] implement KASLR for powerpc/fsl_booke/32 Jason Yan
2019-08-09 10:07 ` [PATCH v6 01/12] powerpc: unify definition of M_IF_NEEDED Jason Yan
2019-08-09 10:07 ` [PATCH v6 02/12] powerpc: move memstart_addr and kernstart_addr to init-common.c Jason Yan
2019-08-09 10:07 ` [PATCH v6 03/12] powerpc: introduce kernstart_virt_addr to store the kernel base Jason Yan
2019-08-09 10:07 ` [PATCH v6 04/12] powerpc/fsl_booke/32: introduce create_tlb_entry() helper Jason Yan
2019-08-27 22:07 ` Scott Wood
2019-08-28 5:33 ` Jason Yan
2019-08-09 10:07 ` [PATCH v6 05/12] powerpc/fsl_booke/32: introduce reloc_kernel_entry() helper Jason Yan
2019-08-09 10:07 ` [PATCH v6 06/12] powerpc/fsl_booke/32: implement KASLR infrastructure Jason Yan
2019-08-28 4:54 ` Scott Wood
2019-08-28 5:47 ` Christophe Leroy
2019-08-29 6:26 ` Jason Yan
2019-08-28 11:03 ` Jason Yan
2019-08-28 16:44 ` Scott Wood
2019-08-09 10:07 ` [PATCH v6 07/12] powerpc/fsl_booke/32: randomize the kernel image offset Jason Yan
2019-08-09 10:07 ` [PATCH v6 08/12] powerpc/fsl_booke/kaslr: clear the original kernel if randomized Jason Yan
2019-08-09 10:07 ` [PATCH v6 09/12] powerpc/fsl_booke/kaslr: support nokaslr cmdline parameter Jason Yan
2019-08-09 10:07 ` [PATCH v6 10/12] powerpc/fsl_booke/kaslr: dump out kernel offset information on panic Jason Yan
2019-08-09 10:07 ` [PATCH v6 11/12] powerpc/fsl_booke/kaslr: export offset in VMCOREINFO ELF notes Jason Yan
2019-08-09 10:08 ` [PATCH v6 12/12] powerpc/fsl_booke/32: Document KASLR implementation Jason Yan
2019-08-19 6:12 ` Jason Yan [this message]
2019-08-27 0:39 ` [PATCH v6 00/12] implement KASLR for powerpc/fsl_booke/32 Jason Yan
2019-08-27 1:33 ` Michael Ellerman
2019-08-28 5:08 ` Scott Wood
2019-08-28 13:01 ` Michael Ellerman
2019-08-28 4:05 ` Scott Wood
2019-08-28 4:59 ` Scott Wood
2019-08-29 2:41 ` Jason Yan
2019-08-29 1:57 ` Jason Yan
2019-09-10 5:34 ` Jason Yan
2019-09-14 14:28 ` Scott Wood
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