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SubjectRe: [PATCH v9 0/8] Carry forward IMA measurement log on kexec on ARM64
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On 11/21/20 5:57 AM, Rob Herring wrote:
> On Fri, Nov 13, 2020 at 11:22:35AM -0800, Lakshmi Ramasubramanian wrote:
>> On kexec file load Integrity Measurement Architecture (IMA) subsystem
>> may verify the IMA signature of the kernel and initramfs, and measure
>> it. The command line parameters passed to the kernel in the kexec call
>> may also be measured by IMA. A remote attestation service can verify
>> a TPM quote based on the TPM event log, the IMA measurement list, and
>> the TPM PCR data. This can be achieved only if the IMA measurement log
>> is carried over from the current kernel to the next kernel across
>> the kexec call.
>>
>> powerpc already supports carrying forward the IMA measurement log on
>> kexec. This patch set adds support for carrying forward the IMA
>> measurement log on kexec on ARM64.
>>
>> This patch set moves the platform independent code defined for powerpc
>> such that it can be reused for other platforms as well. A chosen node
>> namely "linux,ima-kexec-buffer" is added to the DTB for ARM64 to hold
>> the address and the size of the memory reserved to carry
>> the IMA measurement log.
>>
>> This patch set has been tested for ARM64 platform using QEMU.
>> I would like help from the community for testing this change on powerpc.
>> Thanks.
>
> As I mentioned previously, please move the kexec code to drivers/of/. Or
> at least put the infrastructure in place so we're not defining public
> IMA functions and then making them static later.

I am not sure I am following you. Could you please clarify -
In this patch series, per your suggestion, I have moved the architecture
independent kexec code to "drivers/of".

=> drivers/of/ima_kexec.c
=> drivers/of/kexec_fdt.c

Please let me know if I missed something.

>
>> This patch set is based on
>> commit af5043c89a8e ("Merge tag 'acpi-5.10-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm")
>> in https://github.com/torvalds/linux "master" branch.
>>
>> Changelog:
>>
>> v9
>> - Moved delete_fdt_mem_rsv() to drivers/of/kexec_fdt.c
>> - Defined a new function get_ima_kexec_buffer() in
>> drivers/of/ima_kexec.c to replace do_get_kexec_buffer()
>> - Changed remove_ima_kexec_buffer() to the original function name
>> remove_ima_buffer()
>> - Moved remove_ima_buffer() to drivers/of/ima_kexec.c
>> - Moved ima_get_kexec_buffer() and ima_free_kexec_buffer()
>> to security/integrity/ima/ima_kexec.c
>>
>> v8:
>> - Moved remove_ima_kexec_buffer(), do_get_kexec_buffer(), and
>> delete_fdt_mem_rsv() to drivers/of/fdt.c
>> - Moved ima_dump_measurement_list() and ima_add_kexec_buffer()
>> back to security/integrity/ima/ima_kexec.c
>>
>> v7:
>> - Renamed remove_ima_buffer() to remove_ima_kexec_buffer() and moved
>> this function definition to kernel.
>> - Moved delete_fdt_mem_rsv() definition to kernel
>> - Moved ima_dump_measurement_list() and ima_add_kexec_buffer() to
>> a new file namely ima_kexec_fdt.c in IMA
>>
>> v6:
>> - Remove any existing FDT_PROP_IMA_KEXEC_BUFFER property in the device
>> tree and also its corresponding memory reservation in the currently
>> running kernel.
>> - Moved the function remove_ima_buffer() defined for powerpc to IMA
>> and renamed the function to ima_remove_kexec_buffer(). Also, moved
>> delete_fdt_mem_rsv() from powerpc to IMA.
>>
>> v5:
>> - Merged get_addr_size_cells() and do_get_kexec_buffer() into a single
>> function when moving the arch independent code from powerpc to IMA
>> - Reverted the change to use FDT functions in powerpc code and added
>> back the original code in get_addr_size_cells() and
>> do_get_kexec_buffer() for powerpc.
>> - Added fdt_add_mem_rsv() for ARM64 to reserve the memory for
>> the IMA log buffer during kexec.
>> - Fixed the warning reported by kernel test bot for ARM64
>> arch_ima_add_kexec_buffer() - moved this function to a new file
>> namely arch/arm64/kernel/ima_kexec.c
>>
>> v4:
>> - Submitting the patch series on behalf of the original author
>> Prakhar Srivastava <prsriva@linux.microsoft.com>
>> - Moved FDT_PROP_IMA_KEXEC_BUFFER ("linux,ima-kexec-buffer") to
>> libfdt.h so that it can be shared by multiple platforms.
>>
>> v3:
>> Breakup patches further into separate patches.
>> - Refactoring non architecture specific code out of powerpc
>> - Update powerpc related code to use fdt functions
>> - Update IMA buffer read related code to use of functions
>> - Add support to store the memory information of the IMA
>> measurement logs to be carried forward.
>> - Update the property strings to align with documented nodes
>> https://github.com/devicetree-org/dt-schema/pull/46
>>
>> v2:
>> Break patches into separate patches.
>> - Powerpc related Refactoring
>> - Updating the docuemntation for chosen node
>> - Updating arm64 to support IMA buffer pass
>>
>> v1:
>> Refactoring carrying over IMA measuremnet logs over Kexec. This patch
>> moves the non-architecture specific code out of powerpc and adds to
>> security/ima.(Suggested by Thiago)
>> Add Documentation regarding the ima-kexec-buffer node in the chosen
>> node documentation
>>
>> v0:
>> Add a layer of abstraction to use the memory reserved by device tree
>> for ima buffer pass.
>> Add support for ima buffer pass using reserved memory for arm64 kexec.
>> Update the arch sepcific code path in kexec file load to store the
>> ima buffer in the reserved memory. The same reserved memory is read
>> on kexec or cold boot.
>>
>> Lakshmi Ramasubramanian (8):
>> powerpc: fix compiler warnings and errors
>> powerpc: Move delete_fdt_mem_rsv() to drivers/of
>> ima: Define get_ima_kexec_buffer() in drivers/of
>> powerpc: Use get_ima_kexec_buffer to get ima kexec buffer
>> powerpc: Move remove_ima_buffer() to drivers/of
>> powerpc: Move ima_get_kexec_buffer() and ima_free_kexec_buffer() to
>> ima
>> arm64: Store IMA log information in kimage used for kexec
>> arm64: Add IMA kexec buffer to DTB
>>
>> arch/arm64/Kconfig | 1 +
>> arch/arm64/include/asm/ima.h | 18 +++++
>> arch/arm64/include/asm/kexec.h | 3 +
>> arch/arm64/kernel/Makefile | 1 +
>> arch/arm64/kernel/ima_kexec.c | 34 ++++++++
>> arch/arm64/kernel/machine_kexec_file.c | 18 +++++
>> arch/powerpc/include/asm/ima.h | 11 +--
>> arch/powerpc/include/asm/kexec.h | 1 -
>> arch/powerpc/kexec/Makefile | 7 +-
>> arch/powerpc/kexec/file_load.c | 32 --------
>> arch/powerpc/kexec/ima.c | 106 ++-----------------------
>> drivers/of/Makefile | 9 +++
>
>> drivers/of/ima_kexec.c | 91 +++++++++++++++++++++
>> drivers/of/kexec_fdt.c | 55 +++++++++++++
>
> Does this need to be 2 files? Just kexec.c?

Since the functions defined in "ima_kexec.c" and "kexec_fdt.c" are
enabled on 2 different kernel CONFIGs, keeping them in 2 files enables
us to avoid using "#ifdef" in C files.

thanks,
-lakshmi

>
>> include/linux/kexec.h | 24 ++++++
>> security/integrity/ima/ima_kexec.c | 51 ++++++++++++
>> 16 files changed, 313 insertions(+), 149 deletions(-)
>> create mode 100644 arch/arm64/include/asm/ima.h
>> create mode 100644 arch/arm64/kernel/ima_kexec.c
>> create mode 100644 drivers/of/ima_kexec.c
>> create mode 100644 drivers/of/kexec_fdt.c
>>
>> --
>> 2.29.2
>>

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