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SecurityPkg: Fix Tcg2SubmitCommand in TPM field upgrade scenario

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There's a bug that after the device was forced shut down during the tpm
firmware update process, then the TPM will stay in field upgrade mode and
refuse to work properly. This will block TPM startup and cause the device
to bootloop.

Now in the TCG_DXE_DATA struct we don’t have a flag to indicate the
current TPM mode, and we will simply treat the upper Scenario with this
DEVICE_ERROR and set the TPMPresentFlag to FALSE.

Later in Tcg2SubmitCommand we will just return DEVICE_ERROR and skip the
actual TPM recovery.

We should have an extra flag that check for the TPM response code and if
it's TPM_RC_UPGRADE, we knew the device is in field upgrade mode and should
continue the workflow.

We should only return EFI_DEVICE_ERROR when both TPMPresentFlag and
TpmUpdateFlag are false.

The field upgrade is part of TCG spec, and the capsule update/recovery
is part of UEFI spec.
Make this PR to bring in the fix for this corner case.

Signed-off-by: Liqi Qi <liqiqi@microsoft.com>
This commit is contained in:
Liqi Qi 2025-12-08 15:30:00 -08:00 • committed by mergify[bot]
parent 02c88f25f3
commit ba8296810c
1 changed files with 59 additions and 11 deletions
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70
SecurityPkg/Tcg/Tcg2Dxe/Tcg2Dxe.c
View file

@ -79,8 +79,17 @@ typedef struct {
UINTN Next800155EventOffset;
} TCG_EVENT_LOG_AREA_STRUCT;
// Mapping of TPM return status to BIOS/OS TPM support and related flags (TPMPresentFlag, TpmUpdateFlag)
// +-------------------+---------------------+-------------------+----------------+---------------+
// | TPM Return Status | Support TPM in BIOS | Support TPM in OS | TPMPresentFlag | TpmUpdateFlag |
// |-------------------|---------------------|-------------------|----------------|---------------|
// | SUCCESS | YES | YES | TRUE | FALSE |
// | FIELD_UPGRADE | YES | NO | FALSE | TRUE |
// | Other FAIL | NO | NO | FALSE | FALSE |
// +-------------------+---------------------+-------------------+----------------+---------------+
typedef struct _TCG_DXE_DATA {
EFI_TCG2_BOOT_SERVICE_CAPABILITY BsCap;
BOOLEAN TpmUpdateFlag;
TCG_EVENT_LOG_AREA_STRUCT EventLogAreaStruct[TCG_EVENT_LOG_AREA_COUNT_MAX];
BOOLEAN GetEventLogCalled[TCG_EVENT_LOG_AREA_COUNT_MAX];
TCG_EVENT_LOG_AREA_STRUCT FinalEventLogAreaStruct[TCG_EVENT_LOG_AREA_COUNT_MAX];
@ -101,6 +110,7 @@ TCG_DXE_DATA mTcgDxeData = {
0, // NumberOfPCRBanks
0, // ActivePcrBanks
},
FALSE,
};
UINTN mBootAttempts = 0;
@ -1407,6 +1417,8 @@ Tcg2SubmitCommand (
)
{
EFI_STATUS Status;
TPM_RC ResponseCode;
UINT32 CurrentOutputBlockSize;
if ((This == NULL) ||
(InputParameterBlockSize == 0) || (InputParameterBlock == NULL) ||
@ -1415,10 +1427,6 @@ Tcg2SubmitCommand (
return EFI_INVALID_PARAMETER;
}
if (!mTcgDxeData.BsCap.TPMPresentFlag) {
return EFI_DEVICE_ERROR;
}
if (InputParameterBlockSize > mTcgDxeData.BsCap.MaxCommandSize) {
return EFI_INVALID_PARAMETER;
}
@ -1427,13 +1435,53 @@ Tcg2SubmitCommand (
return EFI_INVALID_PARAMETER;
}
Status = Tpm2SubmitCommand (
InputParameterBlockSize,
InputParameterBlock,
&OutputParameterBlockSize,
OutputParameterBlock
);
return Status;
//
// Always attempt to submit the command, but if the TPM is already flagged
// as not present, we expect it to fail other than the capsule update scenario.
//
CurrentOutputBlockSize = OutputParameterBlockSize;
Status = Tpm2SubmitCommand (
InputParameterBlockSize,
InputParameterBlock,
&CurrentOutputBlockSize,
OutputParameterBlock
);
if (EFI_ERROR (Status)) {
return mTcgDxeData.BsCap.TPMPresentFlag ? Status : EFI_DEVICE_ERROR;
}
if (CurrentOutputBlockSize < sizeof (TPM2_RESPONSE_HEADER)) {
DEBUG ((DEBUG_ERROR, "%a: Response buffer too small!\n", __func__));
return EFI_DEVICE_ERROR;
}
//
// Correctly read the response code and swap bytes from Big-Endian to Host order.
// The responseCode field is at offset 6 of the response header.
//
ResponseCode = SwapBytes32 (ReadUnaligned32 ((UINT32 *)(OutputParameterBlock + 6)));
DEBUG ((DEBUG_ERROR, "Response code is %x", ResponseCode));
// If the response code ever equals to TPM_RC_UPGRADE, it means the TPM is in field
// upgrade mode, we set TpmUpdateFlag to TRUE.
if (ResponseCode == TPM_RC_UPGRADE) {
DEBUG ((DEBUG_INFO, "TPM response code TPM_RC_UPDATE received. Setting flag.\n"));
mTcgDxeData.TpmUpdateFlag = TRUE;
}
// Now that we have set the TPMPresentFlag, it should be able to reflect the actual TPM presence
// as long as the device is not in field update mode.
if ((mTcgDxeData.BsCap.TPMPresentFlag == FALSE) && (mTcgDxeData.TpmUpdateFlag == FALSE)) {
DEBUG ((DEBUG_WARN, "%a: TPMPresentFlag is FALSE. Expecting command to fail.\n", __func__));
return EFI_DEVICE_ERROR;
}
// If the response code is not TPM_RC_SUCCESS and the device is not in field update mode, return error.
if ((ResponseCode != TPM_RC_SUCCESS) && (mTcgDxeData.TpmUpdateFlag == FALSE)) {
DEBUG ((DEBUG_ERROR, "%a: Command failed with response code 0x%x\n", __func__, ResponseCode));
return EFI_DEVICE_ERROR;
}
return EFI_SUCCESS;
}
/**