Re: [PATCH] SecurityPkg: Fix TPM2 ACPI measurement.

["Yao, Jiewen" <jiewen.yao@intel.com>]

Reviewed by: Jiewen Yao <Jiewen.yao@intel.com>

> -----Original Message-----
> From: Derek Lin <derek.lin2@hpe.com>
> Sent: Wednesday, November 6, 2019 9:01 AM
> To: derek.lin2@hpe.com; devel@edk2.groups.io
> Cc: jason.spottswood@hpe.com; Yao, Jiewen <jiewen.yao@intel.com>; Wang,
> Jian J <jian.j.wang@intel.com>; Zhang, Chao B <chao.b.zhang@intel.com>
> Subject: [PATCH] SecurityPkg: Fix TPM2 ACPI measurement.
> 
> We have discussed in this thread.
> https://edk2.groups.io/g/devel/topic/32205028
> 
> Before the change, TPM FW upgrade will impact TPM2 ACPI PCR value because
> TPM2 ACPI HID include FW version.
> 
> This change make the measurement before TPM2 HID fixup. So, after TPM FW
> upgrade, the ACPI PCR record remains the same.
> 
> Signed-off-by: Derek Lin <derek.lin2@hpe.com>
> ---
>  SecurityPkg/Tcg/Tcg2Smm/Tcg2Smm.c | 30 ++++++++++++++++--------------
>  1 file changed, 16 insertions(+), 14 deletions(-)
> 
> diff --git a/SecurityPkg/Tcg/Tcg2Smm/Tcg2Smm.c
> b/SecurityPkg/Tcg/Tcg2Smm/Tcg2Smm.c
> index bd786bf479..54966c83ce 100644
> --- a/SecurityPkg/Tcg/Tcg2Smm/Tcg2Smm.c
> +++ b/SecurityPkg/Tcg/Tcg2Smm/Tcg2Smm.c
> @@ -664,7 +664,22 @@ PublishAcpiTable (
>      ));
> 
>    //
> -  // Update TPM2 HID before measuring it to PCR
> +  // Measure to PCR[0] with event EV_POST_CODE ACPI DATA.
> +  // The measurement has to be done before UpdateHID since TPM2 ACPI HID
> +  // imply TPM Firmware Version. Otherwise, the PCR record would be
> +  // different after TPM FW update.
> +  //
> +  TpmMeasureAndLogData(
> +    0,
> +    EV_POST_CODE,
> +    EV_POSTCODE_INFO_ACPI_DATA,
> +    ACPI_DATA_LEN,
> +    Table,
> +    TableSize
> +    );
> +
> +  //
> +  // Update TPM2 HID after measuring it to PCR
>    //
>    Status = UpdateHID(Table);
>    if (EFI_ERROR(Status)) {
> @@ -694,19 +709,6 @@ PublishAcpiTable (
>      }
>    }
> 
> -  //
> -  // Measure to PCR[0] with event EV_POST_CODE ACPI DATA
> -  //
> -  TpmMeasureAndLogData(
> -    0,
> -    EV_POST_CODE,
> -    EV_POSTCODE_INFO_ACPI_DATA,
> -    ACPI_DATA_LEN,
> -    Table,
> -    TableSize
> -    );
> -
> -
>    ASSERT (Table->OemTableId == SIGNATURE_64 ('T', 'p', 'm', '2', 'T', 'a', 'b', 'l'));
>    CopyMem (Table->OemId, PcdGetPtr (PcdAcpiDefaultOemId), sizeof (Table-
> >OemId) );
>    mTcgNvs = AssignOpRegion (Table, SIGNATURE_32 ('T', 'N', 'V', 'S'), (UINT16)
> sizeof (TCG_NVS));
> --
> 2.20.1.windows.1