[U-Boot] [PATCH v4 00/32] Introduce TPMv2.0 support
Tom Rini
trini at konsulko.com
Tue May 15 16:01:10 UTC 2018
On Tue, May 15, 2018 at 11:56:56AM +0200, Miquel Raynal wrote:
> Current U-Boot supports TPM v1.2 specification. The new specification
> (v2.0) is not backward compatible and renames/introduces several
> functions. This series introduces the support for TPMv2.x chips.
>
> First, some cleaning is done in TPM-related code. Then, the code is
> split in two categories: generic code (common for both specifications)
> and specific code (only used by one specification).
>
> Then, basic functionalities are introduced one by one for the v2.x
> specification. TPMv1 vs TPMv2 commands/support distinction is done with
> Kconfig options. Drivers of only one specification can be selected at a
> time.
>
> A new SPI driver following the TPM v2.x specification is introduced. It
> has been tested on a ST TPM but should be usable with others v2.0
> compliant chips.
>
> Finally a full Python test suite is added, as well as a Sandbox driver.
> Regular testing may be done through the test/py/ framework when using
> real hardware as well as the Sandbox driver. The following test has run
> more than 300 times without failing with my setup:
>
> test/py/test.py --bd <board> -k tpm2
>
> Available commands for v2.0 TPMs are:
> * STARTUP
> * SELF TEST
> * CLEAR
> * PCR EXTEND
> * PCR READ
> * GET CAPABILITY
> * DICTIONARY ATTACK LOCK RESET
> * DICTIONARY ATTACK CHANGE PARAMETERS
> * HIERARCHY CHANGE AUTH
>
> Two commands have been written but could not be tested (unsupported by
> the TPM chosen):
> * PCR CHANGE AUTH POLICY
> * PCR CHANGE AUTH VALUE
>
> With this set of function, minimal TPMv2.0 handling is possible with the
> following sequence.
>
> * First, initialize the TPM stack in U-Boot.
>
> > tpm init
>
> * Then send the STARTUP command to the TPM. The flag is slightly
> different between the revisions.
>
> > tpm startup TPM2_SU_CLEAR
>
> * To enable full TPM capabilities, continue the tests (or do them all
> again). It seems like self_test_full always waits for the operation to
> finish, while continue_self_test returns a busy state if called to
> early.
>
> > tpm self_test full
> > tpm self_test continue
>
> * Manage passwords (force_clear also resets a lot of internal stuff).
> Olderly, TAKE OWNERSHIP == CLEAR + CHANGE AUTH. LOCKOUT is an example,
> ENDORSEMENT and PLATFORM hierarchies are available too:
>
> > tpm clear TPM2_RH_LOCKOUT [<pw>]
> > tpm change_auth TPM2_RH_LOCKOUT <new_pw> [<old_pw>]
>
> * Dictionary Attack Mitigation (DAM) parameters can be changed. It is
> possible to reset the failure counter and disable the lockout (values
> erased after a CLEAR). It is then possible to check the parameters
> have been correctly applied.
>
> > tpm dam_reset [<pw>]
> > tpm dam_parameters 0xffff 1 0 [<pw>]
> > tpm get_capability 0x0006 0x020e 0x4000000 4
>
> * PCR policy may be changed (untested).
> PCR can be extended (no protection against packet replay yet).
> PCR can be read (the counter with the number of "extensions" is also
> given).
>
> > tpm pcr_setauthpolicy 0 12345678901234567890123456789012 [<pw>]
> > tpm pcr_read 0 0x4000000
> > tpm pcr_extend 0 0x4000000
>
> Thanks,
> Miquèl
>
> Changes since v3:
> =================
> * Added Simon Glass's RB tags.
> * Moved all the small fixes about lines, alignments, spellings, etc out
> of the big commit splitting the TPM code structure. Multiple commits
> have been made for these changes. Now the split is still done in one
> commit, but it is supposed to be only code moves and headers changes.
> * Used map_sysmem() calls to let Sandbox run TPM commands instead of my
> hack (allocating memory on the go).
> * Updated the documentation to use the new way of declaring parameters:
> s/@param x: y/@x: y/.
> * Added two parameters in the chip private structure to store the number
> of PCRs and the minimum number of bytes needed to address one in a TPM
> command. This should fit all the TIS TPM2 compliant modules.
> * The above change removes some (wrongly) hardcoded values.
> * Changed the error path as suggested in tpm2_get_capability().
> * Minor rephrasing.
> * Explained in tpm2_get_capability() the offset '19'.
> * Removed useless reset of rx_buf[0] in tpm_tis_spi_xfer().
> * Changed the way spi_xfer return code is checked: error out on any
> value != 0 instead of just negative ones.
> * Removed unused functions flagged __maybe_unused as well as well as the
> __maybe_unused flags themselves when not needed.
> * Simplified the validity check of the GPIO as suggested.
> * Updated the compatible property for the SPI modules (as well as the
> bindings docuementation) to be simply "tis,tpm2-spi" which should work
> with most compliant chips. Data is linked to this generic compatible
> in the TPM driver, other values may be added if needed in the future
> to fit other chips that would use different values than the current
> ones (used by Infineon SLB 9670 and ST ST33TPHF20 modules, for
> instance).
Some of the new files have old-style SPDX tags. If there's no further
changes requested, I'll fix these up when applying. Thanks again!
--
Tom
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