From: Michael Ellerman <mpe@ellerman.id.au>
To: Scott Wood <oss@buserror.net>
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 <yanaijie@huawei.com>,
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
Date: Tue, 27 Aug 2019 11:33:51 +1000 [thread overview]
Message-ID: <878srf4cjk.fsf@concordia.ellerman.id.au> (raw)
In-Reply-To: <529fd908-42d6-f96f-daa2-9010f3035879@huawei.com>
Jason Yan <yanaijie@huawei.com> 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
>>>
next prev parent reply other threads:[~2019-08-27 1:33 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 ` [PATCH v6 00/12] implement KASLR for powerpc/fsl_booke/32 Jason Yan
2019-08-27 0:39 ` Jason Yan
2019-08-27 1:33 ` Michael Ellerman [this message]
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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