/** @file
  The library instance provides security service of TPM measure boot.  

Copyright (c) 2009 - 2011, Intel Corporation. All rights reserved.<BR>
This program and the accompanying materials 
are licensed and made available under the terms and conditions of the BSD License 
which accompanies this distribution.  The full text of the license may be found at 
http://opensource.org/licenses/bsd-license.php

THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.

**/

#include <PiDxe.h>

#include <Protocol/TcgService.h>
#include <Protocol/FirmwareVolume2.h>
#include <Protocol/BlockIo.h>
#include <Protocol/DiskIo.h>
#include <Protocol/DevicePathToText.h>

#include <Library/BaseLib.h>
#include <Library/DebugLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/DevicePathLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/BaseCryptLib.h>
#include <Library/PeCoffLib.h>
#include <Library/SecurityManagementLib.h>

//
// Flag to check GPT partition. It only need be measured once.
//
BOOLEAN                           mMeasureGptTableFlag = FALSE;
EFI_GUID                          mZeroGuid = {0, 0, 0, {0, 0, 0, 0, 0, 0, 0, 0}};
UINTN                             mMeasureGptCount = 0;

/**
  Reads contents of a PE/COFF image in memory buffer.

  @param  FileHandle      Pointer to the file handle to read the PE/COFF image.
  @param  FileOffset      Offset into the PE/COFF image to begin the read operation.
  @param  ReadSize        On input, the size in bytes of the requested read operation.  
                          On output, the number of bytes actually read.
  @param  Buffer          Output buffer that contains the data read from the PE/COFF image.
  
  @retval EFI_SUCCESS     The specified portion of the PE/COFF image was read and the size 
**/
EFI_STATUS
EFIAPI
ImageRead (
  IN     VOID    *FileHandle,
  IN     UINTN   FileOffset,
  IN OUT UINTN   *ReadSize,
  OUT    VOID    *Buffer
  )
{
  CopyMem (Buffer, (UINT8 *)((UINTN) FileHandle + FileOffset), *ReadSize);
  return EFI_SUCCESS;
}

/**
  Measure GPT table data into TPM log.

  @param TcgProtocol             Pointer to the located TCG protocol instance.
  @param GptHandle               Handle that GPT partition was installed.

  @retval EFI_SUCCESS            Successfully measure GPT table.
  @retval EFI_UNSUPPORTED        Not support GPT table on the given handle.
  @retval EFI_DEVICE_ERROR       Can't get GPT table because device error.
  @retval EFI_OUT_OF_RESOURCES   No enough resource to measure GPT table.
  @retval other error value
**/
EFI_STATUS
EFIAPI
TcgMeasureGptTable (
  IN  EFI_TCG_PROTOCOL   *TcgProtocol,
  IN  EFI_HANDLE         GptHandle
  )
{
  EFI_STATUS                        Status;
  EFI_BLOCK_IO_PROTOCOL             *BlockIo;
  EFI_DISK_IO_PROTOCOL              *DiskIo;
  EFI_PARTITION_TABLE_HEADER        *PrimaryHeader;
  EFI_PARTITION_ENTRY               *PartitionEntry;
  UINT8                             *EntryPtr;
  UINTN                             NumberOfPartition;
  UINT32                            Index;
  TCG_PCR_EVENT                     *TcgEvent;
  EFI_GPT_DATA                      *GptData;
  UINT32                            EventSize;
  UINT32                            EventNumber;
  EFI_PHYSICAL_ADDRESS              EventLogLastEntry;

  if (mMeasureGptCount > 0) {
    return EFI_SUCCESS;
  }

  Status = gBS->HandleProtocol (GptHandle, &gEfiBlockIoProtocolGuid, (VOID**)&BlockIo);
  if (EFI_ERROR (Status)) {
    return EFI_UNSUPPORTED;
  }
  Status = gBS->HandleProtocol (GptHandle, &gEfiDiskIoProtocolGuid, (VOID**)&DiskIo);
  if (EFI_ERROR (Status)) {
    return EFI_UNSUPPORTED;
  }
  //
  // Read the EFI Partition Table Header
  //  
  PrimaryHeader = (EFI_PARTITION_TABLE_HEADER *) AllocatePool (BlockIo->Media->BlockSize);
  if (PrimaryHeader == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }  
  Status = DiskIo->ReadDisk (
                     DiskIo,
                     BlockIo->Media->MediaId,
                     1 * BlockIo->Media->BlockSize,
                     BlockIo->Media->BlockSize,
                     (UINT8 *)PrimaryHeader
                     );
  if (EFI_ERROR (Status)) {
    DEBUG ((EFI_D_ERROR, "Failed to Read Partition Table Header!\n"));
    FreePool (PrimaryHeader);
    return EFI_DEVICE_ERROR;
  }  
  //
  // Read the partition entry.
  //
  EntryPtr = (UINT8 *)AllocatePool (PrimaryHeader->NumberOfPartitionEntries * PrimaryHeader->SizeOfPartitionEntry);
  if (EntryPtr == NULL) {
    FreePool (PrimaryHeader);
    return EFI_OUT_OF_RESOURCES;
  }
  Status = DiskIo->ReadDisk (
                     DiskIo,
                     BlockIo->Media->MediaId,
                     MultU64x32(PrimaryHeader->PartitionEntryLBA, BlockIo->Media->BlockSize),
                     PrimaryHeader->NumberOfPartitionEntries * PrimaryHeader->SizeOfPartitionEntry,
                     EntryPtr
                     );
  if (EFI_ERROR (Status)) {
    FreePool (PrimaryHeader);
    FreePool (EntryPtr);
    return EFI_DEVICE_ERROR;
  }
  
  //
  // Count the valid partition
  //
  PartitionEntry    = (EFI_PARTITION_ENTRY *)EntryPtr;
  NumberOfPartition = 0;
  for (Index = 0; Index < PrimaryHeader->NumberOfPartitionEntries; Index++) {
    if (!CompareGuid (&PartitionEntry->PartitionTypeGUID, &mZeroGuid)) {
      NumberOfPartition++;  
    }
    PartitionEntry++;
  }

  //
  // Parepare Data for Measurement
  // 
  EventSize = (UINT32)(sizeof (EFI_GPT_DATA) - sizeof (GptData->Partitions) 
                        + NumberOfPartition * PrimaryHeader->SizeOfPartitionEntry);
  TcgEvent = (TCG_PCR_EVENT *) AllocateZeroPool (EventSize + sizeof (TCG_PCR_EVENT));
  if (TcgEvent == NULL) {
    FreePool (PrimaryHeader);
    FreePool (EntryPtr);
    return EFI_OUT_OF_RESOURCES;
  }

  TcgEvent->PCRIndex   = 5;
  TcgEvent->EventType  = EV_EFI_GPT_EVENT;
  TcgEvent->EventSize  = EventSize;
  GptData = (EFI_GPT_DATA *) TcgEvent->Event;  

  //
  // Copy the EFI_PARTITION_TABLE_HEADER and NumberOfPartition
  //  
  CopyMem ((UINT8 *)GptData, (UINT8*)PrimaryHeader, sizeof (EFI_PARTITION_TABLE_HEADER));
  GptData->NumberOfPartitions = NumberOfPartition;
  //
  // Copy the valid partition entry
  //
  PartitionEntry    = (EFI_PARTITION_ENTRY*)EntryPtr;
  NumberOfPartition = 0;
  for (Index = 0; Index < PrimaryHeader->NumberOfPartitionEntries; Index++) {
    if (!CompareGuid (&PartitionEntry->PartitionTypeGUID, &mZeroGuid)) {
      CopyMem (
        (UINT8 *)&GptData->Partitions + NumberOfPartition * sizeof (EFI_PARTITION_ENTRY),
        (UINT8 *)PartitionEntry,
        sizeof (EFI_PARTITION_ENTRY)
        );
      NumberOfPartition++;
    }
    PartitionEntry++;
  }

  //
  // Measure the GPT data
  //
  EventNumber = 1;
  Status = TcgProtocol->HashLogExtendEvent (
             TcgProtocol,
             (EFI_PHYSICAL_ADDRESS) (UINTN) (VOID *) GptData,
             (UINT64) TcgEvent->EventSize,
             TPM_ALG_SHA,
             TcgEvent,
             &EventNumber,
             &EventLogLastEntry
             );
  if (!EFI_ERROR (Status)) {
    mMeasureGptCount++;
  }

  FreePool (PrimaryHeader);
  FreePool (EntryPtr);
  FreePool (TcgEvent);

  return Status;
}

/**
  Measure PE image into TPM log based on the authenticode image hashing in
  PE/COFF Specification 8.0 Appendix A.

  @param[in] TcgProtocol    Pointer to the located TCG protocol instance.
  @param[in] ImageAddress   Start address of image buffer.
  @param[in] ImageSize      Image size
  @param[in] LinkTimeBase   Address that the image is loaded into memory.
  @param[in] ImageType      Image subsystem type.
  @param[in] FilePath       File path is corresponding to the input image.

  @retval EFI_SUCCESS            Successfully measure image.
  @retval EFI_OUT_OF_RESOURCES   No enough resource to measure image.
  @retval other error value
**/
EFI_STATUS
EFIAPI
TcgMeasurePeImage (
  IN  EFI_TCG_PROTOCOL          *TcgProtocol,
  IN  EFI_PHYSICAL_ADDRESS      ImageAddress,
  IN  UINTN                     ImageSize,
  IN  UINTN                     LinkTimeBase,
  IN  UINT16                    ImageType,
  IN  EFI_DEVICE_PATH_PROTOCOL  *FilePath
  )
{
  EFI_STATUS                        Status;
  TCG_PCR_EVENT                     *TcgEvent;
  EFI_IMAGE_LOAD_EVENT              *ImageLoad;
  UINT32                            FilePathSize;
  VOID                              *Sha1Ctx;
  UINTN                             CtxSize;
  EFI_IMAGE_DOS_HEADER              *DosHdr;
  UINT32                            PeCoffHeaderOffset;
  EFI_IMAGE_SECTION_HEADER          *Section;
  UINT8                             *HashBase;
  UINTN                             HashSize;
  UINTN                             SumOfBytesHashed;
  EFI_IMAGE_SECTION_HEADER          *SectionHeader;
  UINTN                             Index, Pos;
  UINT16                            Magic;
  UINT32                            EventSize;
  UINT32                            EventNumber;
  EFI_PHYSICAL_ADDRESS              EventLogLastEntry;
  EFI_IMAGE_OPTIONAL_HEADER_PTR_UNION  Hdr;

  Status        = EFI_SUCCESS;
  ImageLoad     = NULL;
  SectionHeader = NULL;
  Sha1Ctx       = NULL;
  FilePathSize  = (UINT32) GetDevicePathSize (FilePath);

  //
  // Determine destination PCR by BootPolicy
  //
  EventSize = sizeof (*ImageLoad) - sizeof (ImageLoad->DevicePath) + FilePathSize;
  TcgEvent = AllocateZeroPool (EventSize + sizeof (TCG_PCR_EVENT));
  if (TcgEvent == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }

  TcgEvent->EventSize = EventSize;
  ImageLoad           = (EFI_IMAGE_LOAD_EVENT *) TcgEvent->Event;

  switch (ImageType) {
    case EFI_IMAGE_SUBSYSTEM_EFI_APPLICATION:
      TcgEvent->EventType = EV_EFI_BOOT_SERVICES_APPLICATION;
      TcgEvent->PCRIndex  = 4;
      break;
    case EFI_IMAGE_SUBSYSTEM_EFI_BOOT_SERVICE_DRIVER:
      TcgEvent->EventType = EV_EFI_BOOT_SERVICES_DRIVER;
      TcgEvent->PCRIndex  = 2;
      break;
    case EFI_IMAGE_SUBSYSTEM_EFI_RUNTIME_DRIVER:
      TcgEvent->EventType = EV_EFI_RUNTIME_SERVICES_DRIVER;
      TcgEvent->PCRIndex  = 2;
      break;
    default:
      DEBUG ((
        EFI_D_ERROR,
        "TcgMeasurePeImage: Unknown subsystem type %d",
        ImageType
        ));
      ASSERT (FALSE);
      TcgEvent->EventType = ImageType;
      Status = EFI_UNSUPPORTED;
      goto Finish;
  }

  ImageLoad->ImageLocationInMemory = ImageAddress;
  ImageLoad->ImageLengthInMemory   = ImageSize;
  ImageLoad->ImageLinkTimeAddress  = LinkTimeBase;
  ImageLoad->LengthOfDevicePath    = FilePathSize;
  CopyMem (ImageLoad->DevicePath, FilePath, FilePathSize);

  //
  // Check PE/COFF image
  //
  DosHdr = (EFI_IMAGE_DOS_HEADER *) (UINTN) ImageAddress;
  PeCoffHeaderOffset = 0;
  if (DosHdr->e_magic == EFI_IMAGE_DOS_SIGNATURE) {
    PeCoffHeaderOffset = DosHdr->e_lfanew;
  }
  if (((EFI_TE_IMAGE_HEADER *)((UINT8 *) (UINTN) ImageAddress + PeCoffHeaderOffset))->Signature
       == EFI_TE_IMAGE_HEADER_SIGNATURE) {
    goto Finish;
  }

  //
  // PE/COFF Image Measurement
  //
  //    NOTE: The following codes/steps are based upon the authenticode image hashing in
  //      PE/COFF Specification 8.0 Appendix A.
  //
  //

  // 1.  Load the image header into memory.

  // 2.  Initialize a SHA hash context.
  CtxSize = Sha1GetContextSize ();
  Sha1Ctx = AllocatePool (CtxSize);
  if (Sha1Ctx == NULL) {
    Status = EFI_OUT_OF_RESOURCES;
    goto Finish;
  }

  Sha1Init (Sha1Ctx);

  //
  // Measuring PE/COFF Image Header;
  // But CheckSum field and SECURITY data directory (certificate) are excluded
  //
  Hdr.Pe32 = (EFI_IMAGE_NT_HEADERS32 *)((UINT8 *) (UINTN) ImageAddress + PeCoffHeaderOffset);
  Magic    = Hdr.Pe32->OptionalHeader.Magic;
  
  //
  // 3.  Calculate the distance from the base of the image header to the image checksum address.
  // 4.  Hash the image header from its base to beginning of the image checksum.
  //
  HashBase = (UINT8 *) (UINTN) ImageAddress;
  if (Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
    //
    // Use PE32 offset
    //
    HashSize = (UINTN) ((UINT8 *)(&Hdr.Pe32->OptionalHeader.CheckSum) - HashBase);
  } else {
    //
    // Use PE32+ offset
    //
    HashSize = (UINTN) ((UINT8 *)(&Hdr.Pe32Plus->OptionalHeader.CheckSum) - HashBase);
  }

  Sha1Update (Sha1Ctx, HashBase, HashSize);

  //
  // 5.  Skip over the image checksum (it occupies a single ULONG).
  // 6.  Get the address of the beginning of the Cert Directory.
  // 7.  Hash everything from the end of the checksum to the start of the Cert Directory.
  //
  if (Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
    //
    // Use PE32 offset
    //
    HashBase = (UINT8 *) &Hdr.Pe32->OptionalHeader.CheckSum + sizeof (UINT32);
    HashSize = (UINTN) ((UINT8 *)(&Hdr.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]) - HashBase);
  } else {
    //
    // Use PE32+ offset
    //    
    HashBase = (UINT8 *) &Hdr.Pe32Plus->OptionalHeader.CheckSum + sizeof (UINT32);
    HashSize = (UINTN) ((UINT8 *)(&Hdr.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]) - HashBase);
  }

  Sha1Update (Sha1Ctx, HashBase, HashSize);

  //
  // 8.  Skip over the Cert Directory. (It is sizeof(IMAGE_DATA_DIRECTORY) bytes.)
  // 9.  Hash everything from the end of the Cert Directory to the end of image header.
  //
  if (Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
    //
    // Use PE32 offset
    //
    HashBase = (UINT8 *) &Hdr.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY + 1];
    HashSize = Hdr.Pe32->OptionalHeader.SizeOfHeaders -
             (UINTN) ((UINT8 *)(&Hdr.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY + 1]) - (UINT8 *) (UINTN) ImageAddress);
  } else {
    //
    // Use PE32+ offset
    //
    HashBase = (UINT8 *) &Hdr.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY + 1];
    HashSize = Hdr.Pe32Plus->OptionalHeader.SizeOfHeaders -
             (UINTN) ((UINT8 *)(&Hdr.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY + 1]) - (UINT8 *) (UINTN) ImageAddress);
  }
  
  Sha1Update (Sha1Ctx, HashBase, HashSize);

  //
  // 10. Set the SUM_OF_BYTES_HASHED to the size of the header
  //
  if (Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
    //
    // Use PE32 offset
    //
    SumOfBytesHashed = Hdr.Pe32->OptionalHeader.SizeOfHeaders;
  } else {
    //
    // Use PE32+ offset
    //
    SumOfBytesHashed = Hdr.Pe32Plus->OptionalHeader.SizeOfHeaders;
  }

  //
  // 11. Build a temporary table of pointers to all the IMAGE_SECTION_HEADER
  //     structures in the image. The 'NumberOfSections' field of the image
  //     header indicates how big the table should be. Do not include any
  //     IMAGE_SECTION_HEADERs in the table whose 'SizeOfRawData' field is zero.
  //
  SectionHeader = (EFI_IMAGE_SECTION_HEADER *)AllocateZeroPool (sizeof (EFI_IMAGE_SECTION_HEADER) * Hdr.Pe32->FileHeader.NumberOfSections);
  if (SectionHeader == NULL) {
    Status = EFI_OUT_OF_RESOURCES;
    goto Finish;
  }

  //
  // 12.  Using the 'PointerToRawData' in the referenced section headers as
  //      a key, arrange the elements in the table in ascending order. In other
  //      words, sort the section headers according to the disk-file offset of
  //      the section.
  //
  Section = (EFI_IMAGE_SECTION_HEADER *) (
               (UINT8 *) (UINTN) ImageAddress +
               PeCoffHeaderOffset +
               sizeof(UINT32) +
               sizeof(EFI_IMAGE_FILE_HEADER) +
               Hdr.Pe32->FileHeader.SizeOfOptionalHeader
               );
  for (Index = 0; Index < Hdr.Pe32->FileHeader.NumberOfSections; Index++) {
    Pos = Index;
    while ((Pos > 0) && (Section->PointerToRawData < SectionHeader[Pos - 1].PointerToRawData)) {
      CopyMem (&SectionHeader[Pos], &SectionHeader[Pos - 1], sizeof(EFI_IMAGE_SECTION_HEADER));
      Pos--;
    }
    CopyMem (&SectionHeader[Pos], Section, sizeof(EFI_IMAGE_SECTION_HEADER));
    Section += 1;
  }

  //
  // 13.  Walk through the sorted table, bring the corresponding section
  //      into memory, and hash the entire section (using the 'SizeOfRawData'
  //      field in the section header to determine the amount of data to hash).
  // 14.  Add the section's 'SizeOfRawData' to SUM_OF_BYTES_HASHED .
  // 15.  Repeat steps 13 and 14 for all the sections in the sorted table.
  //
  for (Index = 0; Index < Hdr.Pe32->FileHeader.NumberOfSections; Index++) {
    Section  = (EFI_IMAGE_SECTION_HEADER *) &SectionHeader[Index];
    if (Section->SizeOfRawData == 0) {
      continue;
    }
    HashBase = (UINT8 *) (UINTN) ImageAddress + Section->PointerToRawData;
    HashSize = (UINTN) Section->SizeOfRawData;

    Sha1Update (Sha1Ctx, HashBase, HashSize);

    SumOfBytesHashed += HashSize;
  }

  //
  // 16.  If the file size is greater than SUM_OF_BYTES_HASHED, there is extra
  //      data in the file that needs to be added to the hash. This data begins
  //      at file offset SUM_OF_BYTES_HASHED and its length is:
  //             FileSize  -  (CertDirectory->Size)
  //
  if (ImageSize > SumOfBytesHashed) {
    HashBase = (UINT8 *) (UINTN) ImageAddress + SumOfBytesHashed;
    if (Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
      //
      // Use PE32 offset
      //
      HashSize = (UINTN)(ImageSize -
                 Hdr.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY].Size -
                 SumOfBytesHashed);
    } else {
      //
      // Use PE32+ offset
      //
      HashSize = (UINTN)(ImageSize -
                 Hdr.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY].Size -
                 SumOfBytesHashed);      
    }

    Sha1Update (Sha1Ctx, HashBase, HashSize);
  }

  //
  // 17.  Finalize the SHA hash.
  //
  Sha1Final (Sha1Ctx, (UINT8 *)&TcgEvent->Digest);

  //
  // Log the PE data
  //
  EventNumber = 1;
  Status = TcgProtocol->HashLogExtendEvent (
             TcgProtocol,
             (EFI_PHYSICAL_ADDRESS) (UINTN) (VOID *) NULL,
             0,
             TPM_ALG_SHA,
             TcgEvent,
             &EventNumber,
             &EventLogLastEntry
             );

Finish:
  FreePool (TcgEvent);

  if (SectionHeader != NULL) {
    FreePool (SectionHeader);
  }

  if (Sha1Ctx != NULL ) {
    FreePool (Sha1Ctx);
  }
  return Status;
}

/**
  The security handler is used to abstract platform-specific policy 
  from the DXE core response to an attempt to use a file that returns a 
  given status for the authentication check from the section extraction protocol.  

  The possible responses in a given SAP implementation may include locking 
  flash upon failure to authenticate, attestation logging for all signed drivers, 
  and other exception operations.  The File parameter allows for possible logging 
  within the SAP of the driver.

  If File is NULL, then EFI_INVALID_PARAMETER is returned.

  If the file specified by File with an authentication status specified by 
  AuthenticationStatus is safe for the DXE Core to use, then EFI_SUCCESS is returned.

  If the file specified by File with an authentication status specified by 
  AuthenticationStatus is not safe for the DXE Core to use under any circumstances, 
  then EFI_ACCESS_DENIED is returned.

  If the file specified by File with an authentication status specified by 
  AuthenticationStatus is not safe for the DXE Core to use right now, but it 
  might be possible to use it at a future time, then EFI_SECURITY_VIOLATION is 
  returned.

  @param[in, out] AuthenticationStatus  This is the authentication status returned
                                        from the securitymeasurement services for the
                                        input file.
  @param[in]      File       This is a pointer to the device path of the file that is
                             being dispatched. This will optionally be used for logging.
  @param[in]      FileBuffer File buffer matches the input file device path.
  @param[in]      FileSize   Size of File buffer matches the input file device path.

  @retval EFI_SUCCESS            The file specified by File did authenticate, and the
                                 platform policy dictates that the DXE Core may use File.
  @retval EFI_INVALID_PARAMETER  File is NULL.
  @retval EFI_SECURITY_VIOLATION The file specified by File did not authenticate, and
                                 the platform policy dictates that File should be placed
                                 in the untrusted state. A file may be promoted from
                                 the untrusted to the trusted state at a future time
                                 with a call to the Trust() DXE Service.
  @retval EFI_ACCESS_DENIED      The file specified by File did not authenticate, and
                                 the platform policy dictates that File should not be
                                 used for any purpose.

**/
EFI_STATUS
EFIAPI
DxeTpmMeasureBootHandler (
  IN  OUT   UINT32                     AuthenticationStatus,
  IN  CONST EFI_DEVICE_PATH_PROTOCOL   *File,
  IN  VOID                             *FileBuffer OPTIONAL,
  IN  UINTN                            FileSize OPTIONAL
  )
{
  EFI_TCG_PROTOCOL                  *TcgProtocol;
  EFI_STATUS                        Status;
  TCG_EFI_BOOT_SERVICE_CAPABILITY   ProtocolCapability;
  UINT32                            TCGFeatureFlags;
  EFI_PHYSICAL_ADDRESS              EventLogLocation;
  EFI_PHYSICAL_ADDRESS              EventLogLastEntry;
  EFI_DEVICE_PATH_PROTOCOL          *DevicePathNode;
  EFI_DEVICE_PATH_PROTOCOL          *OrigDevicePathNode;
  EFI_HANDLE                        Handle;
  BOOLEAN                           ApplicationRequired;
  PE_COFF_LOADER_IMAGE_CONTEXT      ImageContext;

  if (File == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  Status = gBS->LocateProtocol (&gEfiTcgProtocolGuid, NULL, (VOID **) &TcgProtocol);
  if (EFI_ERROR (Status)) {
    //
    // TCG protocol is not installed. So, TPM is not present.
    // Don't do any measurement, and directly return EFI_SUCCESS.
    //
    return EFI_SUCCESS;
  }

  ProtocolCapability.Size = (UINT8) sizeof (ProtocolCapability);
  Status = TcgProtocol->StatusCheck (
             TcgProtocol, 
             &ProtocolCapability,
             &TCGFeatureFlags,
             &EventLogLocation,
             &EventLogLastEntry
           );
  if (EFI_ERROR (Status) || ProtocolCapability.TPMDeactivatedFlag) {
    //
    // TPM device doesn't work or activate.
    //
    return EFI_SUCCESS;
  }

  //
  // Copy File Device Path
  //
  OrigDevicePathNode = DuplicateDevicePath (File);
  ASSERT (OrigDevicePathNode != NULL);
  
  //
  // 1. Check whether this device path support BlockIo protocol.
  // Is so, this device path may be a GPT device path.
  //
  DevicePathNode = OrigDevicePathNode;
  Status = gBS->LocateDevicePath (&gEfiBlockIoProtocolGuid, &DevicePathNode, &Handle);
  if (!EFI_ERROR (Status) && !mMeasureGptTableFlag) {
    //
    // Find the gpt partion on the given devicepath
    //
    DevicePathNode = OrigDevicePathNode;
    while (!IsDevicePathEnd (DevicePathNode)) {
      //
      // Find the Gpt partition
      //
      if (DevicePathType (DevicePathNode) == MEDIA_DEVICE_PATH &&
            DevicePathSubType (DevicePathNode) == MEDIA_HARDDRIVE_DP) {
        //
        // Check whether it is a gpt partition or not
        //                           
        if (((HARDDRIVE_DEVICE_PATH *) DevicePathNode)->MBRType == MBR_TYPE_EFI_PARTITION_TABLE_HEADER && 
            ((HARDDRIVE_DEVICE_PATH *) DevicePathNode)->SignatureType == SIGNATURE_TYPE_GUID) {

          //
          // Change the partition device path to its parent device path (disk) and get the handle.
          //
          DevicePathNode->Type    = END_DEVICE_PATH_TYPE;
          DevicePathNode->SubType = END_ENTIRE_DEVICE_PATH_SUBTYPE;
          DevicePathNode          = OrigDevicePathNode;
          Status = gBS->LocateDevicePath (
                         &gEfiDiskIoProtocolGuid,
                         &DevicePathNode,
                         &Handle
                         );
          if (!EFI_ERROR (Status)) {
            //
            // Measure GPT disk.
            //
            Status = TcgMeasureGptTable (TcgProtocol, Handle);
            if (!EFI_ERROR (Status)) {
              //
              // GPT disk check done.
              //
              mMeasureGptTableFlag = TRUE;
            }
          }
          FreePool (OrigDevicePathNode);
          OrigDevicePathNode = DuplicateDevicePath (File);
          ASSERT (OrigDevicePathNode != NULL);
          break;
        }
      }
      DevicePathNode    = NextDevicePathNode (DevicePathNode);
    }
  }
  
  //
  // 2. Measure PE image.
  //
  ApplicationRequired = FALSE;

  //
  // Check whether this device path support FV2 protocol.
  //
  DevicePathNode = OrigDevicePathNode;
  Status = gBS->LocateDevicePath (&gEfiFirmwareVolume2ProtocolGuid, &DevicePathNode, &Handle);
  if (!EFI_ERROR (Status)) {
    //
    // Don't check FV image, and directly return EFI_SUCCESS.
    // It can be extended to the specific FV authentication according to the different requirement.
    //
    if (IsDevicePathEnd (DevicePathNode)) {
      return EFI_SUCCESS;
    }
    //
    // The image from Firmware image will not be mearsured.
    // Current policy doesn't measure PeImage from Firmware if it is driver
    // If the got PeImage is application, it will be still be measured.
    //
    ApplicationRequired = TRUE;
  }
  
  //
  // File is not found.
  //
  if (FileBuffer == NULL) {
    Status = EFI_SECURITY_VIOLATION;
    goto Finish;
  }

  //
  // Measure PE Image
  //
  DevicePathNode = OrigDevicePathNode;
  ZeroMem (&ImageContext, sizeof (ImageContext));
  ImageContext.Handle    = (VOID *) FileBuffer;
  ImageContext.ImageRead = (PE_COFF_LOADER_READ_FILE) ImageRead;

  //
  // Get information about the image being loaded
  //
  Status = PeCoffLoaderGetImageInfo (&ImageContext);
  if (EFI_ERROR (Status)) {
    //
    // The information can't be got from the invalid PeImage
    //
    goto Finish;
  }
  
  //
  // Measure only application if Application flag is set
  // Measure drivers and applications if Application flag is not set
  //
  if ((!ApplicationRequired) || 
        (ApplicationRequired && ImageContext.ImageType == EFI_IMAGE_SUBSYSTEM_EFI_APPLICATION)) {  
    //
    // Print the image path to be measured.
    //    
    DEBUG_CODE_BEGIN ();
      CHAR16                            *ToText;
      EFI_DEVICE_PATH_TO_TEXT_PROTOCOL  *DevPathToText;
      Status = gBS->LocateProtocol (
                      &gEfiDevicePathToTextProtocolGuid,
                      NULL,
                      (VOID **) &DevPathToText
                      );
      if (!EFI_ERROR (Status)) {
        ToText = DevPathToText->ConvertDevicePathToText (
                                  DevicePathNode,
                                  FALSE,
                                  TRUE
                                  );
        if (ToText != NULL) {
          DEBUG ((DEBUG_INFO, "The measured image path is %s.\n", ToText));
        }
      }
    DEBUG_CODE_END ();

    //
    // Measure PE image into TPM log.
    //
    Status = TcgMeasurePeImage (
               TcgProtocol,
               (EFI_PHYSICAL_ADDRESS) (UINTN) FileBuffer, 
               FileSize, 
               (UINTN) ImageContext.ImageAddress, 
               ImageContext.ImageType, 
               DevicePathNode
               );
  }

  //
  // Done, free the allocated resource.
  //
Finish:
  FreePool (OrigDevicePathNode);

  return Status;
}

/**
  Register the security handler to provide TPM measure boot service.

  @param  ImageHandle  ImageHandle of the loaded driver.
  @param  SystemTable  Pointer to the EFI System Table.

  @retval  EFI_SUCCESS            Register successfully.
  @retval  EFI_OUT_OF_RESOURCES   No enough memory to register this handler.
**/
EFI_STATUS
EFIAPI
DxeTpmMeasureBootLibConstructor (
  IN EFI_HANDLE        ImageHandle,
  IN EFI_SYSTEM_TABLE  *SystemTable
  )
{
  return RegisterSecurityHandler (
          DxeTpmMeasureBootHandler,
          EFI_AUTH_OPERATION_MEASURE_IMAGE | EFI_AUTH_OPERATION_IMAGE_REQUIRED
          );
}