Re: [PATCH v6 0/2] enhance TPM 2.0 extend function to support multiple PCR banks

[Jarkko Sakkinen]

On Fri, Jan 20, 2017 at 12:05:11PM -0500, Nayna Jain wrote:
> IMA extends its hash measurements in the TPM PCRs, based on policy.
> The existing in-kernel TPM extend function extends only the SHA1
> PCR bank. TPM 2.0 defines multiple PCR banks, to support different
> hash algorithms. The TCG TPM 2.0 Specification[1] recommends
> extending all active PCR banks to prevent malicious users from
> setting unused PCR banks with fake measurements and quoting them.
> This patch set adds support for extending all active PCR banks,
> as recommended.
> 
> The first patch implements the TPM 2.0 capability to retrieve
> the list of active PCR banks.
> 
> The second patch modifies the tpm_pcr_extend() and tpm2_pcr_extend()
> interface to support extending multiple PCR banks. The existing
> tpm_pcr_extend() interface expects only a SHA1 digest. Hence, to
> extend all active PCR banks with differing digest sizes for TPM 2.0,
> the SHA1 digest is padded with 0's as needed.
> 
> [1] TPM 2.0 Specification referred here is "TCG PC Client Specific
> Platform Firmware Profile for TPM 2.0"
> 
> Changelog v6:
> - Patch "tpm: implement TPM 2.0 capability to get active PCR banks"
>   - Fixed the regression - missing tpm_buf_destroy() in
>   in tpm2_get_pcr_allocation(). Thanks Jarkko for noticing.
>   - Added TPM2_ALG_ERROR = 0x0000 to represent invalid algorithm.
> 
> Changelog v5:
> - Patch "tpm: implement TPM 2.0 capability to get active PCR banks"
>  - Included Jarkko's feedbacks
>    - Moved variable declaration to start of function in
>    tpm_pcr_extend()
> 
> 
> Changelog v4:
> - Updated cover letter as per Mimi's feedback.
> - Rebased to Jarkko's latest master branch (4064b6b tpm_tis: use
>   default timeout value if chip reports it as zero)
> - Patch "tpm: implement TPM 2.0 capability to get active PCR banks"
>  - Included Jarkko's feedbacks
>    - Moved call to tpm2_get_pcr_allocation to Patch 2
>    - Renamed struct tpm2_tpms_pcr_selection to struct tpm2_pcr_selection 
>    and moved the struct to before tpm2_get_pcr_allocation()
>    - Fixed code formatting
> - Patch "tpm: enchance TPM 2.0 PCR extend to support multiple banks"
>  - Included Jarkkos' feedbacks
>    - Updated commit msg to mention dependency on CRYPTO_HASH_INFO
>    - Renamed struct tpmt_hash to struct tpm2_digest 
>    - Removed struct tpml_digest_values, tpm2_pcr_extend() now accepts
>    count and digests list as two separate arguments. Added check for
>    count of hashes passed.
>  - Cleaned up struct tpm2_pcr_extend_in as not required anymore with
>  use of tpm_buf
>  - Moved struct tpm2_null_auth_area just before tpm2_pcr_extend() as
>  it is the only function using it for now.
>  - Fixed code formatting
> 
> Changelog v3:
> - Rebased to the Jarkko's latest master branch (8e25809 tpm:
>   Do not print an error message when doing TPM auto startup)
> - Patch "tpm: implement TPM 2.0 capability to get active PCR banks"
>   - Included Jarkko's feedbacks
>      - Removed getcap_in, getcap_out and used tpm_buf for getting
>      capability.
>      - Used ARRAY_SIZE in place of TPM_MAX_PCR_BANKS and included
>      other feedbacks.
> - Patch "tpm: enhance TPM 2.0 PCR extend to support multiple banks"
>      - Fixed kbuild errors
>        - Fixed buf.data uninitialized warning.
>        - Added TCG_TPM dependency on CONFIG_CRYPTO_HASH_INFO in Kconfig.
> 
> Changelog v2:
> 
> - Patch "tpm: implement TPM 2.0 capability to get active PCR banks"
>   - defined structs definition in tpm2-cmd.c.
>   - no_of_active_banks field is removed. Instead, constant
>   TPM2_MAX_PCR_BANKS is defined.
>   - renamed tpm2_get_active_pcr_banks() to tpm2_get_pcr_allocation()
>   - removed generic function tpm2_get_capability().
> 
> - Patch "tpm: enchance TPM 2.0 PCR extend to support multiple banks"
>  - Removed tpm2.h, and defined structs common for extend and event log
>   in tpm_eventlog.h
>  - uses tpm_buf in tpm2_pcr_extend().
> 
> Nayna Jain (2):
>   tpm: implement TPM 2.0 capability to get active PCR banks
>   tpm: enhance TPM 2.0 PCR extend to support multiple banks
> 
>  drivers/char/tpm/Kconfig         |   1 +
>  drivers/char/tpm/tpm-interface.c |  15 +++-
>  drivers/char/tpm/tpm.h           |   8 ++-
>  drivers/char/tpm/tpm2-cmd.c      | 150 ++++++++++++++++++++++++++++-----------
>  drivers/char/tpm/tpm_eventlog.h  |   7 ++
>  5 files changed, 137 insertions(+), 44 deletions(-)
> 
> -- 
> 2.5.0
> 

I need to test these patches but otherwise they're fine...

/Jarkko