audk/SecurityPkg/Library/DxeImageVerificationLib/Measurement.c

/** @file
  Measure TrEE required variable.

Copyright (c) 2013 - 2014, 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 <Guid/ImageAuthentication.h>
#include <IndustryStandard/UefiTcgPlatform.h>
#include <Protocol/TrEEProtocol.h>

#include <Library/UefiBootServicesTableLib.h>
#include <Library/UefiRuntimeServicesTableLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/DebugLib.h>
#include <Library/BaseLib.h>
#include <Library/TpmMeasurementLib.h>

typedef struct {
  CHAR16                                 *VariableName;
  EFI_GUID                               *VendorGuid;
} VARIABLE_TYPE;

typedef struct {
  CHAR16                                 *VariableName;
  EFI_GUID                               *VendorGuid;
  VOID                                   *Data;
  UINTN                                  Size;
} VARIABLE_RECORD;

#define  MEASURED_AUTHORITY_COUNT_MAX  0x100

UINTN            mMeasuredAuthorityCount    = 0;
UINTN            mMeasuredAuthorityCountMax = 0;
VARIABLE_RECORD  *mMeasuredAuthorityList    = NULL;

VARIABLE_TYPE  mVariableType[] = {
  {EFI_IMAGE_SECURITY_DATABASE,  &gEfiImageSecurityDatabaseGuid},
};

/**
  This function will check if VarName should be recorded and return the address of VarName if it is needed.

  @param[in]  VarName           A Null-terminated string that is the name of the vendor's variable.

  @return the address of VarName.
**/
CHAR16 *
AssignVarName (
  IN      CHAR16                    *VarName
  )
{
  UINTN  Index;

  for (Index = 0; Index < sizeof(mVariableType)/sizeof(mVariableType[0]); Index++) {
    if (StrCmp (VarName, mVariableType[Index].VariableName) == 0) {
      return mVariableType[Index].VariableName;
    }
  }

  return NULL;
}

/**
  This function will check if VendorGuid should be recorded and return the address of VendorGuid if it is needed.

  @param[in]  VendorGuid        A unique identifier for the vendor.

  @return the address of VendorGuid.
**/
EFI_GUID *
AssignVendorGuid (
  IN      EFI_GUID                  *VendorGuid
  )
{
  UINTN  Index;

  for (Index = 0; Index < sizeof(mVariableType)/sizeof(mVariableType[0]); Index++) {
    if (CompareGuid (VendorGuid, mVariableType[Index].VendorGuid)) {
      return mVariableType[Index].VendorGuid;
    }
  }

  return NULL;
}

/**
  This function will add variable information to MeasuredAuthorityList.

  @param[in]  VarName           A Null-terminated string that is the name of the vendor's variable.
  @param[in]  VendorGuid        A unique identifier for the vendor.
  @param[in]  VarData           The content of the variable data.  
  @param[in]  VarSize           The size of the variable data.  
 
  @retval EFI_SUCCESS           Operation completed successfully.
  @retval EFI_OUT_OF_RESOURCES  Out of memory.
**/
EFI_STATUS
AddDataMeasured (
  IN      CHAR16                    *VarName,
  IN      EFI_GUID                  *VendorGuid,
  IN      VOID                      *Data,
  IN      UINTN                     Size
  )
{
  VARIABLE_RECORD  *NewMeasuredAuthorityList;

  ASSERT (mMeasuredAuthorityCount <= mMeasuredAuthorityCountMax);
  if (mMeasuredAuthorityCount == mMeasuredAuthorityCountMax) {
    //
    // Need enlarge
    //
    NewMeasuredAuthorityList = AllocateZeroPool (sizeof(VARIABLE_RECORD) * (mMeasuredAuthorityCountMax + MEASURED_AUTHORITY_COUNT_MAX));
    if (NewMeasuredAuthorityList == NULL) {
      return EFI_OUT_OF_RESOURCES;
    }
    if (mMeasuredAuthorityList != NULL) {
      CopyMem (NewMeasuredAuthorityList, mMeasuredAuthorityList, sizeof(VARIABLE_RECORD) * mMeasuredAuthorityCount);
      FreePool (mMeasuredAuthorityList);
    }
    mMeasuredAuthorityList     = NewMeasuredAuthorityList;
    mMeasuredAuthorityCountMax += MEASURED_AUTHORITY_COUNT_MAX;
  }

  //
  // Add new entry
  //
  mMeasuredAuthorityList[mMeasuredAuthorityCount].VariableName = AssignVarName (VarName);
  mMeasuredAuthorityList[mMeasuredAuthorityCount].VendorGuid   = AssignVendorGuid (VendorGuid);
  mMeasuredAuthorityList[mMeasuredAuthorityCount].Size         = Size;
  mMeasuredAuthorityList[mMeasuredAuthorityCount].Data         = AllocatePool (Size);
  if (mMeasuredAuthorityList[mMeasuredAuthorityCount].Data == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }
  CopyMem (mMeasuredAuthorityList[mMeasuredAuthorityCount].Data, Data, Size);
  mMeasuredAuthorityCount++;

  return EFI_SUCCESS;
}

/**
  This function will return if this variable is already measured.

  @param[in]  VarName           A Null-terminated string that is the name of the vendor's variable.
  @param[in]  VendorGuid        A unique identifier for the vendor.
  @param[in]  VarData           The content of the variable data.  
  @param[in]  VarSize           The size of the variable data.  

  @retval TRUE  The data is already measured.
  @retval FALSE The data is not measured yet.
**/
BOOLEAN
IsDataMeasured (
  IN      CHAR16                    *VarName,
  IN      EFI_GUID                  *VendorGuid,
  IN      VOID                      *Data,
  IN      UINTN                     Size
  )
{
  UINTN  Index;

  for (Index = 0; Index < mMeasuredAuthorityCount; Index++) {
    if ((StrCmp (VarName, mMeasuredAuthorityList[Index].VariableName) == 0) &&
        (CompareGuid (VendorGuid, mMeasuredAuthorityList[Index].VendorGuid)) &&
        (CompareMem (Data, mMeasuredAuthorityList[Index].Data, Size) == 0) &&
        (Size == mMeasuredAuthorityList[Index].Size)) {
      return TRUE;
    }
  }

  return FALSE;
}

/**
  This function will return if this variable is SecureAuthority Variable.

  @param[in]  VariableName      A Null-terminated string that is the name of the vendor's variable.
  @param[in]  VendorGuid        A unique identifier for the vendor.

  @retval TRUE  This is SecureAuthority Variable
  @retval FALSE This is not SecureAuthority Variable
**/
BOOLEAN
IsSecureAuthorityVariable (
  IN CHAR16                                 *VariableName,
  IN EFI_GUID                               *VendorGuid
  )
{
  UINTN   Index;

  for (Index = 0; Index < sizeof(mVariableType)/sizeof(mVariableType[0]); Index++) {
    if ((StrCmp (VariableName, mVariableType[Index].VariableName) == 0) && 
        (CompareGuid (VendorGuid, mVariableType[Index].VendorGuid))) {
      return TRUE;
    }
  }
  return FALSE;
}

/**
  Measure and log an EFI variable, and extend the measurement result into a specific PCR.

  @param[in]  VarName           A Null-terminated string that is the name of the vendor's variable.
  @param[in]  VendorGuid        A unique identifier for the vendor.
  @param[in]  VarData           The content of the variable data.  
  @param[in]  VarSize           The size of the variable data.  
 
  @retval EFI_SUCCESS           Operation completed successfully.
  @retval EFI_OUT_OF_RESOURCES  Out of memory.
  @retval EFI_DEVICE_ERROR      The operation was unsuccessful.

**/
EFI_STATUS
EFIAPI
MeasureVariable (
  IN      CHAR16                    *VarName,
  IN      EFI_GUID                  *VendorGuid,
  IN      VOID                      *VarData,
  IN      UINTN                     VarSize
  )
{
  EFI_STATUS                        Status;
  UINTN                             VarNameLength;
  EFI_VARIABLE_DATA_TREE            *VarLog;
  UINT32                            VarLogSize;

  //
  // The EFI_VARIABLE_DATA_TREE.VariableData value shall be the EFI_SIGNATURE_DATA value
  // from the EFI_SIGNATURE_LIST that contained the authority that was used to validate the image
  //
  VarNameLength      = StrLen (VarName);
  VarLogSize = (UINT32)(sizeof (*VarLog) + VarNameLength * sizeof (*VarName) + VarSize
                        - sizeof (VarLog->UnicodeName) - sizeof (VarLog->VariableData));

  VarLog = (EFI_VARIABLE_DATA_TREE *) AllocateZeroPool (VarLogSize);
  if (VarLog == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }

  CopyMem (&VarLog->VariableName, VendorGuid, sizeof(VarLog->VariableName));
  VarLog->UnicodeNameLength  = VarNameLength;
  VarLog->VariableDataLength = VarSize;
  CopyMem (
     VarLog->UnicodeName,
     VarName,
     VarNameLength * sizeof (*VarName)
     );
  CopyMem (
     (CHAR16 *)VarLog->UnicodeName + VarNameLength,
     VarData,
     VarSize
     );

  DEBUG ((EFI_D_INFO, "DxeImageVerification: MeasureVariable (Pcr - %x, EventType - %x, ", (UINTN)7, (UINTN)EV_EFI_VARIABLE_AUTHORITY));
  DEBUG ((EFI_D_INFO, "VariableName - %s, VendorGuid - %g)\n", VarName, VendorGuid));

  Status = TpmMeasureAndLogData (
             7,
             EV_EFI_VARIABLE_AUTHORITY,
             VarLog,
             VarLogSize,
             VarLog,
             VarLogSize
             );
  FreePool (VarLog);

  return Status;
}

/**
  SecureBoot Hook for processing image verification.

  @param[in] VariableName                 Name of Variable to be found.
  @param[in] VendorGuid                   Variable vendor GUID.
  @param[in] DataSize                     Size of Data found. If size is less than the
                                          data, this value contains the required size.
  @param[in] Data                         Data pointer.

**/
VOID
EFIAPI
SecureBootHook (
  IN CHAR16                                 *VariableName,
  IN EFI_GUID                               *VendorGuid,
  IN UINTN                                  DataSize,
  IN VOID                                   *Data
  )
{
  EFI_STATUS                        Status;

  if (!IsSecureAuthorityVariable (VariableName, VendorGuid)) {
    return ;
  }

  if (IsDataMeasured (VariableName, VendorGuid, Data, DataSize)) {
    DEBUG ((EFI_D_ERROR, "MeasureSecureAuthorityVariable - IsDataMeasured\n"));
    return ;
  }

  Status = MeasureVariable (
             VariableName,
             VendorGuid,
             Data,
             DataSize
             );
  DEBUG ((EFI_D_INFO, "MeasureBootPolicyVariable - %r\n", Status));

  if (!EFI_ERROR (Status)) {
    AddDataMeasured (VariableName, VendorGuid, Data, DataSize);
  }

  return ;
}