Re: [PATCH] SecurityPkg: Debug code to audit BIOS TPM extend operations


Yao, Jiewen
 

Pushed: 8ed8568922be9b5f7111fc1297317106aba7ab52

-----Original Message-----
From: Gonzalez Del Cueto, Rodrigo <rodrigo.gonzalez.del.cueto@intel.com>
Sent: Friday, December 17, 2021 10:47 AM
To: devel@edk2.groups.io
Cc: Gonzalez Del Cueto, Rodrigo <rodrigo.gonzalez.del.cueto@intel.com>; Yao,
Jiewen <jiewen.yao@intel.com>; Wang, Jian J <jian.j.wang@intel.com>
Subject: [PATCH] SecurityPkg: Debug code to audit BIOS TPM extend operations

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2858

In V2: Fixed patch format and uncrustify cleanup

In V1: Add debug functionality to examine TPM extend operations
performed by BIOS and inspect the PCR 00 value prior to
any BIOS measurements.

Signed-off-by: Rodrigo Gonzalez del Cueto
<rodrigo.gonzalez.del.cueto@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Jian J Wang <jian.j.wang@intel.com>
---
SecurityPkg/Include/Library/Tpm2CommandLib.h | 33
+++++++++++++++++++++++++--------
SecurityPkg/Library/Tpm2CommandLib/Tpm2Integrity.c | 190
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
SecurityPkg/Tcg/Tcg2Pei/Tcg2Pei.c | 9 ++++++++-
3 files changed, 222 insertions(+), 10 deletions(-)

diff --git a/SecurityPkg/Include/Library/Tpm2CommandLib.h
b/SecurityPkg/Include/Library/Tpm2CommandLib.h
index 2e83a2f474..a2fb97f18d 100644
--- a/SecurityPkg/Include/Library/Tpm2CommandLib.h
+++ b/SecurityPkg/Include/Library/Tpm2CommandLib.h
@@ -1,7 +1,7 @@
/** @file
This library is used by other modules to send TPM2 command.

-Copyright (c) 2013 - 2018, Intel Corporation. All rights reserved. <BR>
+Copyright (c) 2013 - 2021, Intel Corporation. All rights reserved. <BR>
SPDX-License-Identifier: BSD-2-Clause-Patent

**/
@@ -503,9 +503,9 @@ Tpm2PcrExtend (
EFI_STATUS
EFIAPI
Tpm2PcrEvent (
- IN TPMI_DH_PCR PcrHandle,
- IN TPM2B_EVENT *EventData,
- OUT TPML_DIGEST_VALUES *Digests
+ IN TPMI_DH_PCR PcrHandle,
+ IN TPM2B_EVENT *EventData,
+ OUT TPML_DIGEST_VALUES *Digests
);

/**
@@ -522,10 +522,10 @@ Tpm2PcrEvent (
EFI_STATUS
EFIAPI
Tpm2PcrRead (
- IN TPML_PCR_SELECTION *PcrSelectionIn,
- OUT UINT32 *PcrUpdateCounter,
- OUT TPML_PCR_SELECTION *PcrSelectionOut,
- OUT TPML_DIGEST *PcrValues
+ IN TPML_PCR_SELECTION *PcrSelectionIn,
+ OUT UINT32 *PcrUpdateCounter,
+ OUT TPML_PCR_SELECTION *PcrSelectionOut,
+ OUT TPML_DIGEST *PcrValues
);

/**
@@ -1113,4 +1113,21 @@ GetDigestFromDigestList (
OUT VOID *Digest
);

+/**
+ This function will query the TPM to determine which hashing algorithms and
+ get the digests of all active and supported PCR banks of a specific PCR
register.
+
+ @param[in] PcrHandle The index of the PCR register to be read.
+ @param[out] HashList List of digests from PCR register being read.
+
+ @retval EFI_SUCCESS The Pcr was read successfully.
+ @retval EFI_DEVICE_ERROR The command was unsuccessful.
+**/
+EFI_STATUS
+EFIAPI
+Tpm2PcrReadForActiveBank (
+ IN TPMI_DH_PCR PcrHandle,
+ OUT TPML_DIGEST *HashList
+ );
+
#endif
diff --git a/SecurityPkg/Library/Tpm2CommandLib/Tpm2Integrity.c
b/SecurityPkg/Library/Tpm2CommandLib/Tpm2Integrity.c
index 8dde5f34a2..94e93b2642 100644
--- a/SecurityPkg/Library/Tpm2CommandLib/Tpm2Integrity.c
+++ b/SecurityPkg/Library/Tpm2CommandLib/Tpm2Integrity.c
@@ -1,7 +1,7 @@
/** @file
Implement TPM2 Integrity related command.

-Copyright (c) 2013 - 2018, Intel Corporation. All rights reserved. <BR>
+Copyright (c) 2013 - 2021, Intel Corporation. All rights reserved. <BR>
SPDX-License-Identifier: BSD-2-Clause-Patent

**/
@@ -138,6 +138,23 @@ Tpm2PcrExtend (
&Digests->digests[Index].digest,
DigestSize
);
+
+ DEBUG_CODE_BEGIN ();
+ UINTN Index2;
+ DEBUG ((
+ DEBUG_VERBOSE,
+ "Tpm2PcrExtend - Hash = 0x%04x, Pcr[%02d], digest = ",
+ Digests->digests[Index].hashAlg,
+ (UINT8)PcrHandle
+ ));
+
+ for (Index2 = 0; Index2 < DigestSize; Index2++) {
+ DEBUG ((DEBUG_VERBOSE, "%02x ", Buffer[Index2]));
+ }
+
+ DEBUG ((DEBUG_VERBOSE, "\n"));
+ DEBUG_CODE_END ();
+
Buffer += DigestSize;
}

@@ -172,6 +189,11 @@ Tpm2PcrExtend (
return EFI_DEVICE_ERROR;
}

+ DEBUG_CODE_BEGIN ();
+ DEBUG ((DEBUG_VERBOSE, "Tpm2PcrExtend: PCR read after extend...\n"));
+ Tpm2PcrReadForActiveBank (PcrHandle, NULL);
+ DEBUG_CODE_END ();
+
//
// Unmarshal the response
//
@@ -705,3 +727,169 @@ Done:
ZeroMem (&LocalAuthSession.hmac, sizeof (LocalAuthSession.hmac));
return Status;
}
+
+/**
+ This function will query the TPM to determine which hashing algorithms and
+ get the digests of all active and supported PCR banks of a specific PCR
register.
+
+ @param[in] PcrHandle The index of the PCR register to be read.
+ @param[out] HashList List of digests from PCR register being read.
+
+ @retval EFI_SUCCESS The Pcr was read successfully.
+ @retval EFI_DEVICE_ERROR The command was unsuccessful.
+**/
+EFI_STATUS
+EFIAPI
+Tpm2PcrReadForActiveBank (
+ IN TPMI_DH_PCR PcrHandle,
+ OUT TPML_DIGEST *HashList
+ )
+{
+ EFI_STATUS Status;
+ TPML_PCR_SELECTION Pcrs;
+ TPML_PCR_SELECTION PcrSelectionIn;
+ TPML_PCR_SELECTION PcrSelectionOut;
+ TPML_DIGEST PcrValues;
+ UINT32 PcrUpdateCounter;
+ UINT8 PcrIndex;
+ UINT32 TpmHashAlgorithmBitmap;
+ TPMI_ALG_HASH CurrentPcrBankHash;
+ UINT32 ActivePcrBanks;
+ UINT32 TcgRegistryHashAlg;
+ UINTN Index;
+ UINTN Index2;
+
+ PcrIndex = (UINT8)PcrHandle;
+
+ if ((PcrIndex < 0) ||
+ (PcrIndex >= IMPLEMENTATION_PCR))
+ {
+ return EFI_INVALID_PARAMETER;
+ }
+
+ ZeroMem (&PcrSelectionIn, sizeof (PcrSelectionIn));
+ ZeroMem (&PcrUpdateCounter, sizeof (UINT32));
+ ZeroMem (&PcrSelectionOut, sizeof (PcrSelectionOut));
+ ZeroMem (&PcrValues, sizeof (PcrValues));
+ ZeroMem (&Pcrs, sizeof (TPML_PCR_SELECTION));
+
+ DEBUG ((DEBUG_INFO, "ReadPcr - %02d\n", PcrIndex));
+
+ //
+ // Read TPM capabilities
+ //
+ Status = Tpm2GetCapabilityPcrs (&Pcrs);
+
+ if (EFI_ERROR (Status)) {
+ DEBUG ((DEBUG_ERROR, "ReadPcr: Unable to read TPM capabilities\n"));
+ return EFI_DEVICE_ERROR;
+ }
+
+ //
+ // Get Active Pcrs
+ //
+ Status = Tpm2GetCapabilitySupportedAndActivePcrs (
+ &TpmHashAlgorithmBitmap,
+ &ActivePcrBanks
+ );
+
+ if (EFI_ERROR (Status)) {
+ DEBUG ((DEBUG_ERROR, "ReadPcr: Unable to read TPM capabilities and
active PCRs\n"));
+ return EFI_DEVICE_ERROR;
+ }
+
+ //
+ // Select from Active PCRs
+ //
+ for (Index = 0; Index < Pcrs.count; Index++) {
+ CurrentPcrBankHash = Pcrs.pcrSelections[Index].hash;
+
+ switch (CurrentPcrBankHash) {
+ case TPM_ALG_SHA1:
+ DEBUG ((DEBUG_VERBOSE, "HASH_ALG_SHA1 Present\n"));
+ TcgRegistryHashAlg = HASH_ALG_SHA1;
+ break;
+ case TPM_ALG_SHA256:
+ DEBUG ((DEBUG_VERBOSE, "HASH_ALG_SHA256 Present\n"));
+ TcgRegistryHashAlg = HASH_ALG_SHA256;
+ break;
+ case TPM_ALG_SHA384:
+ DEBUG ((DEBUG_VERBOSE, "HASH_ALG_SHA384 Present\n"));
+ TcgRegistryHashAlg = HASH_ALG_SHA384;
+ break;
+ case TPM_ALG_SHA512:
+ DEBUG ((DEBUG_VERBOSE, "HASH_ALG_SHA512 Present\n"));
+ TcgRegistryHashAlg = HASH_ALG_SHA512;
+ break;
+ case TPM_ALG_SM3_256:
+ DEBUG ((DEBUG_VERBOSE, "HASH_ALG_SM3 Present\n"));
+ TcgRegistryHashAlg = HASH_ALG_SM3_256;
+ break;
+ default:
+ //
+ // Unsupported algorithm
+ //
+ DEBUG ((DEBUG_VERBOSE, "Unknown algorithm present\n"));
+ TcgRegistryHashAlg = 0;
+ break;
+ }
+
+ //
+ // Skip unsupported and inactive PCR banks
+ //
+ if ((TcgRegistryHashAlg & ActivePcrBanks) == 0) {
+ DEBUG ((DEBUG_VERBOSE, "Skipping unsupported or inactive bank:
0x%04x\n", CurrentPcrBankHash));
+ continue;
+ }
+
+ //
+ // Select PCR from current active bank
+ //
+ PcrSelectionIn.pcrSelections[PcrSelectionIn.count].hash =
Pcrs.pcrSelections[Index].hash;
+ PcrSelectionIn.pcrSelections[PcrSelectionIn.count].sizeofSelect =
PCR_SELECT_MAX;
+ PcrSelectionIn.pcrSelections[PcrSelectionIn.count].pcrSelect[0] = (PcrIndex <
8) ? 1 << PcrIndex : 0;
+ PcrSelectionIn.pcrSelections[PcrSelectionIn.count].pcrSelect[1] = (PcrIndex >
7) && (PcrIndex < 16) ? 1 << (PcrIndex - 8) : 0;
+ PcrSelectionIn.pcrSelections[PcrSelectionIn.count].pcrSelect[2] = (PcrIndex >
15) ? 1 << (PcrIndex - 16) : 0;
+ PcrSelectionIn.count++;
+ }
+
+ //
+ // Read PCRs
+ //
+ Status = Tpm2PcrRead (
+ &PcrSelectionIn,
+ &PcrUpdateCounter,
+ &PcrSelectionOut,
+ &PcrValues
+ );
+
+ if (EFI_ERROR (Status)) {
+ DEBUG ((DEBUG_ERROR, "Tpm2PcrRead failed Status = %r \n", Status));
+ return EFI_DEVICE_ERROR;
+ }
+
+ for (Index = 0; Index < PcrValues.count; Index++) {
+ DEBUG ((
+ DEBUG_INFO,
+ "ReadPcr - HashAlg = 0x%04x, Pcr[%02d], digest = ",
+ PcrSelectionOut.pcrSelections[Index].hash,
+ PcrIndex
+ ));
+
+ for (Index2 = 0; Index2 < PcrValues.digests[Index].size; Index2++) {
+ DEBUG ((DEBUG_INFO, "%02x ", PcrValues.digests[Index].buffer[Index2]));
+ }
+
+ DEBUG ((DEBUG_INFO, "\n"));
+ }
+
+ if (HashList != NULL) {
+ CopyMem (
+ HashList,
+ &PcrValues,
+ sizeof (TPML_DIGEST)
+ );
+ }
+
+ return EFI_SUCCESS;
+}
diff --git a/SecurityPkg/Tcg/Tcg2Pei/Tcg2Pei.c
b/SecurityPkg/Tcg/Tcg2Pei/Tcg2Pei.c
index a97a4e7f2d..622989aff3 100644
--- a/SecurityPkg/Tcg/Tcg2Pei/Tcg2Pei.c
+++ b/SecurityPkg/Tcg/Tcg2Pei/Tcg2Pei.c
@@ -1,7 +1,7 @@
/** @file
Initialize TPM2 device and measure FVs before handing off control to DXE.

-Copyright (c) 2015 - 2020, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2015 - 2021, Intel Corporation. All rights reserved.<BR>
Copyright (c) 2017, Microsoft Corporation. All rights reserved. <BR>
SPDX-License-Identifier: BSD-2-Clause-Patent

@@ -1106,6 +1106,13 @@ PeimEntryMA (
}
}

+ DEBUG_CODE_BEGIN ();
+ //
+ // Peek into TPM PCR 00 before any BIOS measurement.
+ //
+ Tpm2PcrReadForActiveBank (00, NULL);
+ DEBUG_CODE_END ();
+
//
// Only install TpmInitializedPpi on success
//
--
2.26.2.windows.1

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