system76-edk2/SecurityPkg/Library/SecTpmMeasurementLib/SecTpmMeasurementLibTdx.c

/** @file
  This library is used by other modules to measure data to TPM.

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

**/

#include <PiPei.h>
#include <Guid/CcEventHob.h>
#include <Library/BaseLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/DebugLib.h>
#include <Library/HashLib.h>
#include <Library/HobLib.h>
#include <Library/PrintLib.h>
#include <IndustryStandard/Tpm20.h>
#include <Protocol/CcMeasurement.h>
#include <Library/TpmMeasurementLib.h>

#pragma pack(1)

typedef struct {
  UINT32           Count;
  TPMI_ALG_HASH    HashAlg;
  BYTE             Sha384[SHA384_DIGEST_SIZE];
} TDX_DIGEST_VALUE;

#pragma pack()

#define INVALID_PCR2MR_INDEX  0xFF

/**
  Get the mapped RTMR index based on the input PCRIndex.
  RTMR[0]  => PCR[1,7]
  RTMR[1]  => PCR[2,3,4,5]
  RTMR[2]  => PCR[8~15]
  RTMR[3]  => NA
  Note:
    PCR[0] is mapped to MRTD and should not appear here.
    PCR[6] is reserved for OEM. It is not used.

   @param[in] PCRIndex The input PCR index

   @retval UINT8   The mapped RTMR index.
**/
UINT8
GetMappedRtmrIndex (
  IN UINT32  PCRIndex
  )
{
  UINT8  RtmrIndex;

  if ((PCRIndex == 6) || (PCRIndex == 0) || (PCRIndex > 15)) {
    DEBUG ((DEBUG_ERROR, "Invalid PCRIndex(%d) map to MR Index.\n", PCRIndex));
    ASSERT (FALSE);
    return INVALID_PCR2MR_INDEX;
  }

  RtmrIndex = 0;
  if ((PCRIndex == 1) || (PCRIndex == 7)) {
    RtmrIndex = 0;
  } else if ((PCRIndex >= 2) && (PCRIndex < 6)) {
    RtmrIndex = 1;
  } else if ((PCRIndex >= 8) && (PCRIndex <= 15)) {
    RtmrIndex = 2;
  }

  return RtmrIndex;
}

/**
  Tpm measure and log data, and extend the measurement result into a specific PCR.

  @param[in]  PcrIndex         PCR Index.
  @param[in]  EventType        Event type.
  @param[in]  EventLog         Measurement event log.
  @param[in]  LogLen           Event log length in bytes.
  @param[in]  HashData         The start of the data buffer to be hashed, extended.
  @param[in]  HashDataLen      The length, in bytes, of the buffer referenced by HashData

  @retval EFI_SUCCESS           Operation completed successfully.
  @retval EFI_UNSUPPORTED       TPM device not available.
  @retval EFI_OUT_OF_RESOURCES  Out of memory.
  @retval EFI_DEVICE_ERROR      The operation was unsuccessful.
**/
EFI_STATUS
EFIAPI
TpmMeasureAndLogData (
  IN UINT32  PcrIndex,
  IN UINT32  EventType,
  IN VOID    *EventLog,
  IN UINT32  LogLen,
  IN VOID    *HashData,
  IN UINT64  HashDataLen
  )
{
  EFI_STATUS          Status;
  UINT32              RtmrIndex;
  VOID                *EventHobData;
  TCG_PCR_EVENT2      *TcgPcrEvent2;
  UINT8               *DigestBuffer;
  TDX_DIGEST_VALUE    *TdxDigest;
  TPML_DIGEST_VALUES  DigestList;
  UINT8               *Ptr;

  if (!TdIsEnabled ()) {
    return EFI_UNSUPPORTED;
  }

  RtmrIndex = GetMappedRtmrIndex (PcrIndex);
  if (RtmrIndex == INVALID_PCR2MR_INDEX) {
    return EFI_INVALID_PARAMETER;
  }

  DEBUG ((DEBUG_INFO, "Creating TdTcg2PcrEvent PCR[%d]/RTMR[%d] EventType 0x%x\n", PcrIndex, RtmrIndex, EventType));

  Status = HashAndExtend (
             RtmrIndex,
             (VOID *)HashData,
             HashDataLen,
             &DigestList
             );

  if (EFI_ERROR (Status)) {
    DEBUG ((DEBUG_INFO, "Failed to HashAndExtend. %r\n", Status));
    return Status;
  }

  //
  // Use TDX_DIGEST_VALUE in the GUID HOB DataLength calculation
  // to reserve enough buffer to hold TPML_DIGEST_VALUES compact binary
  // which is limited to a SHA384 digest list
  //
  EventHobData = BuildGuidHob (
                   &gCcEventEntryHobGuid,
                   sizeof (TcgPcrEvent2->PCRIndex) + sizeof (TcgPcrEvent2->EventType) +
                   sizeof (TDX_DIGEST_VALUE) +
                   sizeof (TcgPcrEvent2->EventSize) + LogLen
                   );

  if (EventHobData == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }

  Ptr = (UINT8 *)EventHobData;
  //
  // Initialize PcrEvent data now
  //
  RtmrIndex++;
  CopyMem (Ptr, &RtmrIndex, sizeof (UINT32));
  Ptr += sizeof (UINT32);
  CopyMem (Ptr, &EventType, sizeof (TCG_EVENTTYPE));
  Ptr += sizeof (TCG_EVENTTYPE);

  DigestBuffer = Ptr;

  TdxDigest          = (TDX_DIGEST_VALUE *)DigestBuffer;
  TdxDigest->Count   = 1;
  TdxDigest->HashAlg = TPM_ALG_SHA384;
  CopyMem (
    TdxDigest->Sha384,
    DigestList.digests[0].digest.sha384,
    SHA384_DIGEST_SIZE
    );

  Ptr += sizeof (TDX_DIGEST_VALUE);

  CopyMem (Ptr, &LogLen, sizeof (UINT32));
  Ptr += sizeof (UINT32);
  CopyMem (Ptr, EventLog, LogLen);
  Ptr += LogLen;

  Status = EFI_SUCCESS;
  return Status;
}