lkml.org 
[lkml]   [2023]   [Aug]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH v6 0/5] riscv: Introduce KASLR
From


在 2023/8/17 21:10, Alexandre Ghiti 写道:
> Hi Song,
>
> On Tue, Aug 15, 2023 at 1:24 PM Song Shuai <songshuaishuai@tinylab.org> wrote:
>>
>>
>> Hi, Alex:
>>
>> 在 2023/7/22 20:38, Alexandre Ghiti 写道:
>>> The following KASLR implementation allows to randomize the kernel mapping:
>>>
>>> - virtually: we expect the bootloader to provide a seed in the device-tree
>>> - physically: only implemented in the EFI stub, it relies on the firmware to
>>> provide a seed using EFI_RNG_PROTOCOL. arm64 has a similar implementation
>>> hence the patch 3 factorizes KASLR related functions for riscv to take
>>> advantage.
>>>
>>> The new virtual kernel location is limited by the early page table that only
>>> has one PUD and with the PMD alignment constraint, the kernel can only take
>>> < 512 positions.
>>>
>>
>> I have gone through the code and tested this series with RiscVVirt edk2.
>> All seems good to me, you can add :
>>
>> Tested-by: Song Shuai <songshuaishuai@tinylab.org>
>>
>> And a few questions about patch 2 ("riscv: Dump out kernel offset
>> information on panic"):
>>
>> 1. The dump_kernel_offset() function would output "Kernel Offset: 0x0
>> from 0xffffffff80000000" when booting with "nokaslr" option.
>>
>> How about disabling the registration of "kernel_offset_notifier" with
>> "nokaslr" option?
>
> I'd rather keep it as it shows the "nokaslr" flag was taken into account.
>
>>
>> 2. Inspired by patch 2, I added the Crash KASLR support based on this
>> series [1].
>> So is it necessary to keep this patch if we have Crash KASLR support?
>
> I don't understand your question here

Crash can automatically calculate virt_offset by comparing the vmlinux
and vmcore. If this patch is just intended to assist Crash in setting
the "--kaslr offset," it might be deleted; if not just keep it.

>
>>
>>
>> [1]:
>> https://lore.kernel.org/linux-riscv/20230815104800.705753-1-songshuaishuai@tinylab.org/T/#u
>>
>>> base-commit-tag: v6.5-rc1
>>>
>>> Changes in v6:
>>> * Fix reintroduced build failures by compiling kaslr.c only for arm64
>>> and riscv, as suggested by Ard
>>>
>>> Changes in v5:
>>> * Renamed efi-stub-kaslr.c into kaslr.c and fix commit log of patch 3,
>>> as suggested by Ard
>>> * Removed stubs since the kaslr functions were moved to their own file
>>> (and then does not trigger any build failure for architectures that do
>>> not call those functions since they are in their own compilation unit)
>>>
>>> Changes in v4:
>>> * Fix efi_get_kimg macro that returned nothing
>>> * Moved new kaslr functions into their own files to avoid zboot link
>>> failures, as suggested by Ard
>>>
>>> Changes in v3:
>>> * Rebase on top of 6.4-rc2
>>> * Make RANDOMIZE_BASE depend on 64bit
>>> * Fix efi_icache_sync and efi_get_kimg_min_align which were undefined
>>> in x86 (and certainly other archs)
>>> * Add patch 4 to fix warning on rv32
>>>
>>> Changes in v2:
>>> * Rebase on top of 6.3-rc1
>>> * Add a riscv cache sync after memcpying the kernel
>>> * Add kaslr_offset implementation for KCOV
>>> * Add forward declaration to quiet LLVM
>>>
>>> Alexandre Ghiti (5):
>>> riscv: Introduce virtual kernel mapping KASLR
>>> riscv: Dump out kernel offset information on panic
>>> arm64: libstub: Move KASLR handling functions to kaslr.c
>>> libstub: Fix compilation warning for rv32
>>> riscv: libstub: Implement KASLR by using generic functions
>>>
>>> arch/arm64/include/asm/efi.h | 2 +
>>> arch/riscv/Kconfig | 19 +++
>>> arch/riscv/include/asm/efi.h | 2 +
>>> arch/riscv/include/asm/page.h | 3 +
>>> arch/riscv/kernel/image-vars.h | 1 +
>>> arch/riscv/kernel/pi/Makefile | 2 +-
>>> arch/riscv/kernel/pi/cmdline_early.c | 13 ++
>>> arch/riscv/kernel/pi/fdt_early.c | 30 ++++
>>> arch/riscv/kernel/setup.c | 25 ++++
>>> arch/riscv/mm/init.c | 36 ++++-
>>> drivers/firmware/efi/libstub/Makefile | 4 +-
>>> drivers/firmware/efi/libstub/arm64-stub.c | 117 ++--------------
>>> drivers/firmware/efi/libstub/efistub.h | 8 ++
>>> drivers/firmware/efi/libstub/kaslr.c | 159 ++++++++++++++++++++++
>>> drivers/firmware/efi/libstub/riscv-stub.c | 33 ++---
>>> 15 files changed, 328 insertions(+), 126 deletions(-)
>>> create mode 100644 arch/riscv/kernel/pi/fdt_early.c
>>> create mode 100644 drivers/firmware/efi/libstub/kaslr.c
>>>
>>
>> --
>> Thanks
>> Song Shuai
>
> Thanks for testing this and your suggestions!
>
> Alex
>

--
Thanks
Song Shuai

\
 
 \ /
  Last update: 2023-08-17 15:30    [W:0.073 / U:3.116 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site