SecurityPkg/Library/Tpm2CommandLib/Tpm2Context.c

/** @file
  Implement TPM2 Context related command.

Copyright (c) 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 <IndustryStandard/UefiTcgPlatform.h>
#include <Library/Tpm2CommandLib.h>
#include <Library/Tpm2DeviceLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/BaseLib.h>
#include <Library/DebugLib.h>

#pragma pack(1)

typedef struct {
  TPM2_COMMAND_HEADER       Header;
  TPMI_DH_CONTEXT           FlushHandle;
} TPM2_FLUSH_CONTEXT_COMMAND;

typedef struct {
  TPM2_RESPONSE_HEADER      Header;
} TPM2_FLUSH_CONTEXT_RESPONSE;

#pragma pack()

/**
  This command causes all context associated with a loaded object or session to be removed from TPM memory.

  @param[in]  FlushHandle        The handle of the item to flush.
  
  @retval EFI_SUCCESS            Operation completed successfully.
  @retval EFI_DEVICE_ERROR       The command was unsuccessful.
**/
EFI_STATUS
EFIAPI
Tpm2FlushContext (
  IN      TPMI_DH_CONTEXT           FlushHandle
  )
{
  EFI_STATUS                        Status;
  TPM2_FLUSH_CONTEXT_COMMAND        SendBuffer;
  TPM2_FLUSH_CONTEXT_RESPONSE       RecvBuffer;
  UINT32                            SendBufferSize;
  UINT32                            RecvBufferSize;

  //
  // Construct command
  //
  SendBuffer.Header.tag = SwapBytes16(TPM_ST_NO_SESSIONS);
  SendBuffer.Header.commandCode = SwapBytes32(TPM_CC_FlushContext);

  SendBuffer.FlushHandle = SwapBytes32 (FlushHandle);
 
  SendBufferSize = (UINT32) sizeof (SendBuffer);
  SendBuffer.Header.paramSize = SwapBytes32 (SendBufferSize);

  //
  // send Tpm command
  //
  RecvBufferSize = sizeof (RecvBuffer);
  Status = Tpm2SubmitCommand (SendBufferSize, (UINT8 *)&SendBuffer, &RecvBufferSize, (UINT8 *)&RecvBuffer);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  if (RecvBufferSize < sizeof (TPM2_RESPONSE_HEADER)) {
    DEBUG ((EFI_D_ERROR, "Tpm2FlushContext - RecvBufferSize Error - %x\n", RecvBufferSize));
    return EFI_DEVICE_ERROR;
  }
  if (SwapBytes32(RecvBuffer.Header.responseCode) != TPM_RC_SUCCESS) {
    DEBUG ((EFI_D_ERROR, "Tpm2FlushContext - responseCode - %x\n", SwapBytes32(RecvBuffer.Header.responseCode)));
    return EFI_DEVICE_ERROR;
  }

  return EFI_SUCCESS;
}