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

[Ilias Apalodimas <ilias.apalodimas@linaro.org>]

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.

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 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
> > >