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SubjectRe: [PATCH v12 0/5] x86/boot/KASLR: Parse ACPI table and limit KASLR to choosing immovable memory
On Thu, Nov 29, 2018 at 12:32:46PM -0500, Masayoshi Mizuma wrote:
>Hi Chao,
>
>Thank you for your continued working.

Thanks for your test.

>
>Could you please build your patches before sending?

Sorry for the mistake, I build it with the whole patches.
I found there are some problems with the method to splite patch.
I will rework on it and build every commit.

Thanks,
Chao Fan

>Your patches depend on the following kconfig,
>so please build them under the config combination.
>
>RANDOMIZE_BASE
>MEMORY_HOTREMOVE
>EARLY_PARSE_RSDP
>KEXEC
>EFI
>
>Thanks,
>Masa
>
>On Thu, Nov 29, 2018 at 04:16:26PM +0800, Chao Fan wrote:
>> ***Background:
>> People reported that KASLR may randomly choose some positions
>> which are located in movable memory regions. This will break memory
>> hotplug feature and make the movable memory chosen by KASLR can't be
>> removed.
>>
>> ***Solutions:
>> Get the information of memory hot-remove, then KASLR will know the
>> right regions. Information about memory hot-remove is in ACPI
>> tables, which will be parsed after start_kernel(), so that KASLR
>> can't get the information.
>>
>> Somebody suggest to add a kernel parameter to specify the
>> immovable memory so that limit KASLR in these regions. Then I make
>> a patchset. After several versions, Ingo gave a suggestion:
>> https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1634024.html
>> Follow Ingo's suggestion, imitate the ACPI code to parse the ACPI
>> tables, so that the kaslr can get necessary memory information in
>> ACPI tables.
>> I think ACPI code is an independent part, so imitate the codes
>> and functions to 'compressed/' directory, so that kaslr won't
>> influence the initialization of ACPI.
>>
>> PATCH 1/5 Add get_acpi_rsdp() to parse RSDP in cmdline from KEXEC
>> PATCH 2/5 Add efi_get_rsdp_addr() to find RSDP from EFI table when
>> booting from EFI.
>> PATCH 3/5 Add bios_get_rsdp_addr() to search RSDP in memory when EFI
>> table not found.
>> PATCH 4/5 Compute SRAT table from RSDP and walk SRAT table to store
>> the immovable memory regions.
>> PATCH 5/5 Calculate the intersection between memory regions from e820/efi
>> memory table and immovable memory regions. Limit KASLR to
>> choosing these regions for randomization.
>>
>> v1->v2:
>> - Simplify some code.
>> Follow Baoquan He's suggestion:
>> - Reuse the head file of acpi code.
>>
>> v2->v3:
>> - Test in more conditions, so remove the 'RFC' tag.
>> - Change some comments.
>>
>> v3->v4:
>> Follow Thomas Gleixner's suggetsion:
>> - Put the whole efi related function into #define CONFIG_EFI and return
>> false in the other stub.
>>
>> v4->v5:
>> Follow Dou Liyang's suggestion:
>> - Add more comments about some functions based on kernel code.
>> - Change some typo in comments.
>> - Clean useless variable.
>> - Add check for the boundary of array.
>> - Add check for 'movable_node' parameter
>>
>> v5->v6:
>> Follow Baoquan He's suggestion:
>> - Change some log.
>> - Add the check for acpi_rsdp
>> - Change some code logical to make code clear
>>
>> v6->v7:
>> Follow Rafael's suggestion:
>> - Add more comments and patch log.
>> Follow test robot's suggestion:
>> - Add "static" tag for function
>>
>> v7-v8:
>> Follow Kees Cook's suggestion:
>> - Use mem_overlaps() to check memory region.
>> - Use #ifdef in the definition of function.
>>
>> v8-v9:
>> Follow Boris' suggestion:
>> - Change code style.
>> - Splite PATCH 1/3 to more path.
>> - Introduce some new function
>> - Use existing function to rework some code
>> Follow Masayoshi's suggetion:
>> - Make code more readable
>>
>> v9->v10:
>> Follow Baoquan's suggestion:
>> - Change some log
>> - Merge last two patch together.
>>
>> v10->v11:
>> Follow Boris' suggestion:
>> - Link kstrtoull() instead of copying it.
>> - Drop the useless wrapped function.
>>
>> v11->v12:
>> Follow Boris' suggestion:
>> - Change patch log and code comments.
>> - Add 'CONFIG_EARLY_PARSE_RSDP' to make code easy to read
>> - Put strtoull() to misc.c
>> Follow Masa's suggestion:
>> - Remove the detection for 'movable_node'
>> - Change the code logical about cmdline_find_option()
>>
>> Any comments will be welcome.
>>
>>
>> Chao Fan (5):
>> x86/boot: Add get_acpi_rsdp() to parse RSDP in cmdline from KEXEC
>> x86/boot: Add efi_get_rsdp_addr() to find RSDP from EFI table
>> x86/boot: Add bios_get_rsdp_addr() to search RSDP in memory
>> x86/boot: Parse SRAT table from RSDP and store immovable memory
>> x86/boot/KASLR: Limit KASLR to extracting kernel in immovable memory
>>
>> arch/x86/Kconfig | 10 +
>> arch/x86/boot/compressed/Makefile | 2 +
>> arch/x86/boot/compressed/acpitb.c | 322 ++++++++++++++++++++++++++++++
>> arch/x86/boot/compressed/kaslr.c | 79 ++++++--
>> arch/x86/boot/compressed/misc.c | 5 +
>> arch/x86/boot/compressed/misc.h | 24 +++
>> lib/kstrtox.c | 5 +
>> 7 files changed, 432 insertions(+), 15 deletions(-)
>> create mode 100644 arch/x86/boot/compressed/acpitb.c
>>
>> --
>> 2.19.1
>>
>>
>>
>
>


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