Re: [PATCH v9 0/8] Carry forward IMA measurement log on kexec on ARM64
From: Lakshmi Ramasubramanian
Date: Sat Nov 21 2020 - 14:47:09 EST
On 11/21/20 6:38 AM, Lakshmi Ramasubramanian wrote:
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.
The following two arch independent kexec functions are required only
when CONFIG_IMA is enabled. So I moved them under security/integrity/ima
=> ima_get_kexec_buffer()
=> ima_free_kexec_buffer()
But the other arch independent kexec functions have been moved to
drivers/of.
I am not sure if you wanted ima_get_kexec_buffer() and
ima_free_kexec_buffer() to also be moved to "drivers/of". Please clarify.
thanks,
-lakshmi
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@xxxxxxxxxxxxxxxxxxx>
- 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