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

Eddie James
2023-02-22T14:59:52Z

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
>>>>