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 v4 00/10] implement KASLR for powerpc/fsl_booke/32
Date: Tue, 6 Aug 2019 09:29:58 +0800 [thread overview]
Message-ID: <50bc5134-231d-f518-07f9-41451361a7c3@huawei.com> (raw)
In-Reply-To: <20190805064335.19156-1-yanaijie@huawei.com>
Hi Christophe ,
Can you take a look at patch 6,7,9 of this version?
Thank you,
Jason
On 2019/8/5 14:43, 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.
>
> 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 (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 | 27 +-
> arch/powerpc/kernel/head_fsl_booke.S | 55 ++-
> arch/powerpc/kernel/kaslr_booke.c | 427 ++++++++++++++++++
> arch/powerpc/kernel/machine_kexec.c | 1 +
> arch/powerpc/kernel/misc_64.S | 5 -
> arch/powerpc/kernel/setup-common.c | 19 +
> 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, 560 insertions(+), 50 deletions(-)
> create mode 100644 arch/powerpc/kernel/kaslr_booke.c
>
prev parent reply other threads:[~2019-08-06 1:30 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-05 6:43 [PATCH v4 00/10] implement KASLR for powerpc/fsl_booke/32 Jason Yan
2019-08-05 6:43 ` [PATCH v4 01/10] powerpc: unify definition of M_IF_NEEDED Jason Yan
2019-08-05 6:43 ` [PATCH v4 02/10] powerpc: move memstart_addr and kernstart_addr to init-common.c Jason Yan
2019-08-05 6:43 ` [PATCH v4 03/10] powerpc: introduce kimage_vaddr to store the kernel base Jason Yan
2019-08-05 6:43 ` [PATCH v4 04/10] powerpc/fsl_booke/32: introduce create_tlb_entry() helper Jason Yan
2019-08-05 6:43 ` [PATCH v4 05/10] powerpc/fsl_booke/32: introduce reloc_kernel_entry() helper Jason Yan
2019-08-05 6:43 ` [PATCH v4 06/10] powerpc/fsl_booke/32: implement KASLR infrastructure Jason Yan
2019-08-06 7:52 ` Christophe Leroy
2019-08-05 6:43 ` [PATCH v4 07/10] powerpc/fsl_booke/32: randomize the kernel image offset Jason Yan
2019-08-06 7:56 ` Christophe Leroy
2019-08-07 3:16 ` Jason Yan
2019-08-05 6:43 ` [PATCH v4 08/10] powerpc/fsl_booke/kaslr: clear the original kernel if randomized Jason Yan
2019-08-05 6:43 ` [PATCH v4 09/10] powerpc/fsl_booke/kaslr: support nokaslr cmdline parameter Jason Yan
2019-08-06 7:59 ` Christophe Leroy
2019-08-07 3:22 ` Jason Yan
2019-08-05 6:43 ` [PATCH v4 10/10] powerpc/fsl_booke/kaslr: dump out kernel offset information on panic Jason Yan
2019-08-06 1:29 ` Jason Yan [this message]
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