[PATCH v5 0/6] tpm: Support boot measurements

[Eddie James]

On 2/22/23 05:33, Ilias Apalodimas wrote:
> Hi Eddie,
>
> On Tue, Feb 21, 2023 at 04:38:58PM -0600, Eddie James wrote:
>> On 2/6/23 06:20, Ilias Apalodimas wrote:
>>> Thanks Eddie,
>>>
>>> I quickly tested this but the EFI subsystem fails to initialize the TCG
>>> protocol properly now.  Unfortunately I am on a business trip and I won't
>>> be able to take a look into why till next week
>>
>> Hi Ilias,
>>
>>
>> I haven't had the opportunity to test this, have you?
>>
>>
>> Thanks,
>>
>> Eddie
>>
>>
>>> Cheers
>>> /Ilias
>>>
> Still going through the code so bear with me.
> It seems that the EFI failure is coming from tcg2_platform_get_log()
> specifically if none of linux,sml-base nor tpm_event_log_addr if present in
> the dtb.
> One thing we should change here is look for tpm_event_log_addr first.  The
> reason is that this is a very 'special' case in which TF-A fills in an
> eventlog for us, while linux,sml-base is more generic so I'd rather
> explicitly prefer TF-A id it prepared an eventlog for us.


OK, thanks, this is helpful, I'll have a look.


>
> On the failure now, if none of the nodes is present we are looking for
> 'memory-region' within the TPM node?  Looking at the DT specs the tpm
> should only support "compatible, label, linux,sml-base/size' am I missing
> something?


I just had a commit merged for the reserved memory region: 
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/drivers/char/tpm/eventlog/of.c?id=1e2714bb83fc783d58701967391bea242c65eaff

It isn't documented anywhere so far...


Thanks,

Eddie


>
> I also had to apply [0] for this to compile.  You can 'easily' test the EFI
> changes by doing a 'printenv -e'.  This will at least initialize the efi
> subsystem and install the needed EFI tables (you need CMD_NVEDIT_EFI=y)
>
> [0] https://source.denx.de/u-boot/custodians/u-boot-tpm/-/commit/d473596cd6900117485014476c70c49f202bd8da
>
>
> Hope this helps a bit. Let me know if I can help in any other way.
> Don't bother *testing* the eventlog for EFI on a full linux boot. I'll run
> that on v6
>
> /Ilias
>
>
>>> On Thu, Feb 02, 2023 at 11:05:25AM -0600, Eddie James wrote:
>>>> This series adds support for measuring the boot images more generically
>>>> than the existing EFI support. Several EFI functions have been moved to
>>>> the TPM layer. The series includes optional measurement from the bootm
>>>> command.
>>>> A new test case has been added for the bootm measurement to test the new
>>>> path, and the sandbox TPM2 driver has been updated to support this use
>>>> case.
>>>> This series is based on Ilias' auto-startup series:
>>>> https://lore.kernel.org/u-boot/20230126081844.591148-1-ilias.apalodimas@linaro.org/
>>>>
>>>> Changes since v4:
>>>>    - Remove tcg2_measure_event function and check for NULL data in
>>>>      tcg2_measure_data
>>>>    - Use tpm_auto_startup
>>>>    - Fix efi_tcg2.c compilation for removing tcg2_pcr_read function
>>>>    - Change PCR indexes for initrd and dtb
>>>>    - Drop u8 casting in measurement test
>>>>    - Use bullets in documentation
>>>>
>>>> Changes since v3:
>>>>    - Reordered headers
>>>>    - Refactored more of EFI code into common code
>>>>       Removed digest_info structure and instead used the common alg_to_mask
>>>>         and alg_to_len
>>>>       Improved event log parsing in common code to get it equivalent to EFI
>>>>         Common code now extends PCR if previous bootloader stage couldn't
>>>>         No need to allocate memory in the common code, so EFI copies the
>>>>         discovered buffer like it did before
>>>>       Rename efi measure_event function
>>>>
>>>> Changes since v2:
>>>>    - Add documentation.
>>>>    - Changed reserved memory address to the top of the RAM for sandbox dts.
>>>>    - Add measure state to booti and bootz.
>>>>    - Skip measurement for EFI images that should be measured
>>>>
>>>> Changes since v1:
>>>>    - Refactor TPM layer functions to allow EFI system to use them, and
>>>>      remove duplicate EFI functions.
>>>>    - Add test case
>>>>    - Drop #ifdefs for bootm
>>>>    - Add devicetree measurement config option
>>>>    - Update sandbox TPM driver
>>>>
>>>> Eddie James (6):
>>>>     tpm: Fix spelling for tpmu_ha union
>>>>     tpm: Support boot measurements
>>>>     bootm: Support boot measurement
>>>>     tpm: sandbox: Update for needed TPM2 capabilities
>>>>     test: Add sandbox TPM boot measurement
>>>>     doc: Add measured boot documentation
>>>>
>>>>    arch/sandbox/dts/sandbox.dtsi  |   14 +
>>>>    arch/sandbox/dts/test.dts      |   13 +
>>>>    boot/Kconfig                   |   23 +
>>>>    boot/bootm.c                   |   70 +++
>>>>    cmd/booti.c                    |    1 +
>>>>    cmd/bootm.c                    |    2 +
>>>>    cmd/bootz.c                    |    1 +
>>>>    configs/sandbox_defconfig      |    1 +
>>>>    doc/usage/index.rst            |    1 +
>>>>    doc/usage/measured_boot.rst    |   23 +
>>>>    drivers/tpm/tpm2_tis_sandbox.c |  100 +++-
>>>>    include/bootm.h                |    2 +
>>>>    include/efi_tcg2.h             |   44 --
>>>>    include/image.h                |    1 +
>>>>    include/test/suites.h          |    1 +
>>>>    include/tpm-v2.h               |  246 +++++++-
>>>>    lib/efi_loader/efi_tcg2.c      | 1010 +++-----------------------------
>>>>    lib/tpm-v2.c                   |  771 ++++++++++++++++++++++++
>>>>    test/boot/Makefile             |    1 +
>>>>    test/boot/measurement.c        |   66 +++
>>>>    test/cmd_ut.c                  |    2 +
>>>>    21 files changed, 1383 insertions(+), 1010 deletions(-)
>>>>    create mode 100644 doc/usage/measured_boot.rst
>>>>    create mode 100644 test/boot/measurement.c
>>>>
>>>> --
>>>> 2.31.1
>>>>