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    SubjectRe: [PATCH v7 2/2] tpm: add securityfs support for TPM 2.0 firmware event log
    On Tue, Jan 03, 2017 at 01:09:18PM +0530, Nayna wrote:
    >
    >
    > On 01/03/2017 03:42 AM, Jarkko Sakkinen wrote:
    > > On Sun, Dec 11, 2016 at 12:35:33AM -0500, Nayna Jain wrote:
    > > > Unlike the device driver support for TPM 1.2, the TPM 2.0 does
    > > > not support the securityfs pseudo files for displaying the
    > > > firmware event log.
    > > >
    > > > This patch enables support for providing the TPM 2.0 event log in
    > > > binary form. TPM 2.0 event log supports a crypto agile format that
    > > > records multiple digests, which is different from TPM 1.2. This
    > > > patch enables the tpm_bios_log_setup for TPM 2.0 and adds the
    > > > event log parser which understand the TPM 2.0 crypto agile format.
    > > >
    > > > Signed-off-by: Nayna Jain <nayna@linux.vnet.ibm.com>
    > >
    > > There is something fundamentally wrong in this commit.
    > >
    > > You must not allow this feature unless CONFIG_OF is set. It is the only
    > > interface where the supply path of the event log is well defined on
    > > platforms that include a TPM 2.0 chip.
    >
    > As per current implementation, if ACPI with TPM 2.0 doesn't support event
    > log, tpm_read_log_acpi() is expected to return rc and tpm_bios_log_setup
    > will not create securityfs. This is inline with our design for TPM 1.2 event
    > log.

    At minimum you must have a check for TPM_CHIP_FLAG_TPM2 in the beginning
    of tpm_read_log_acpi. It is wrong to even try to open TCPA in this case.

    /Jarkko

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