system76-edk2/SecurityPkg/Library/Tpm2CommandLib/Tpm2Session.c

/** @file
  Implement TPM2 Session 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_OBJECT            TpmKey;
  TPMI_DH_ENTITY            Bind;
  TPM2B_NONCE               NonceCaller;
  TPM2B_ENCRYPTED_SECRET    Salt;
  TPM_SE                    SessionType;
  TPMT_SYM_DEF              Symmetric;
  TPMI_ALG_HASH             AuthHash;
} TPM2_START_AUTH_SESSION_COMMAND;

typedef struct {
  TPM2_RESPONSE_HEADER      Header;
  TPMI_SH_AUTH_SESSION      SessionHandle;
  TPM2B_NONCE               NonceTPM;
} TPM2_START_AUTH_SESSION_RESPONSE;

#pragma pack()

/**
  This command is used to start an authorization session using alternative methods of
  establishing the session key (sessionKey) that is used for authorization and encrypting value.

  @param[in]  TpmKey             Handle of a loaded decrypt key used to encrypt salt.
  @param[in]  Bind               Entity providing the authValue.
  @param[in]  NonceCaller        Initial nonceCaller, sets nonce size for the session.
  @param[in]  Salt               Value encrypted according to the type of tpmKey.
  @param[in]  SessionType        Indicates the type of the session.
  @param[in]  Symmetric          The algorithm and key size for parameter encryption.
  @param[in]  AuthHash           Hash algorithm to use for the session.
  @param[out] SessionHandle      Handle for the newly created session.
  @param[out] NonceTPM           The initial nonce from the TPM, used in the computation of the sessionKey.
  
  @retval EFI_SUCCESS            Operation completed successfully.
  @retval EFI_DEVICE_ERROR       The command was unsuccessful.
**/
EFI_STATUS
EFIAPI
Tpm2StartAuthSession (
  IN      TPMI_DH_OBJECT            TpmKey,
  IN      TPMI_DH_ENTITY            Bind,
  IN      TPM2B_NONCE               *NonceCaller,
  IN      TPM2B_ENCRYPTED_SECRET    *Salt,
  IN      TPM_SE                    SessionType,
  IN      TPMT_SYM_DEF              *Symmetric,
  IN      TPMI_ALG_HASH             AuthHash,
     OUT  TPMI_SH_AUTH_SESSION      *SessionHandle,
     OUT  TPM2B_NONCE               *NonceTPM
  )
{
  EFI_STATUS                        Status;
  TPM2_START_AUTH_SESSION_COMMAND   SendBuffer;
  TPM2_START_AUTH_SESSION_RESPONSE  RecvBuffer;
  UINT32                            SendBufferSize;
  UINT32                            RecvBufferSize;
  UINT8                             *Buffer;

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

  SendBuffer.TpmKey = SwapBytes32 (TpmKey);
  SendBuffer.Bind = SwapBytes32 (Bind);
  Buffer = (UINT8 *)&SendBuffer.NonceCaller;

  WriteUnaligned16 ((UINT16 *)Buffer, SwapBytes16 (NonceCaller->size));
  Buffer += sizeof(UINT16);
  CopyMem (Buffer, NonceCaller->buffer, NonceCaller->size);
  Buffer += NonceCaller->size;

  WriteUnaligned16 ((UINT16 *)Buffer, SwapBytes16 (Salt->size));
  Buffer += sizeof(UINT16);
  CopyMem (Buffer, Salt->secret, Salt->size);
  Buffer += Salt->size;

  *(TPM_SE *)Buffer = SessionType;
  Buffer++;

  WriteUnaligned16 ((UINT16 *)Buffer, SwapBytes16 (Symmetric->algorithm));
  Buffer += sizeof(UINT16);
  switch (Symmetric->algorithm) {
  case TPM_ALG_NULL:
    break;
  case TPM_ALG_AES:
    WriteUnaligned16 ((UINT16 *)Buffer, SwapBytes16 (Symmetric->keyBits.aes));
    Buffer += sizeof(UINT16);
    WriteUnaligned16 ((UINT16 *)Buffer, SwapBytes16 (Symmetric->mode.aes));
    Buffer += sizeof(UINT16);
    break;
  case TPM_ALG_SM4:
    WriteUnaligned16 ((UINT16 *)Buffer, SwapBytes16 (Symmetric->keyBits.SM4));
    Buffer += sizeof(UINT16);
    WriteUnaligned16 ((UINT16 *)Buffer, SwapBytes16 (Symmetric->mode.SM4));
    Buffer += sizeof(UINT16);
    break;
  case TPM_ALG_SYMCIPHER:
    WriteUnaligned16 ((UINT16 *)Buffer, SwapBytes16 (Symmetric->keyBits.sym));
    Buffer += sizeof(UINT16);
    WriteUnaligned16 ((UINT16 *)Buffer, SwapBytes16 (Symmetric->mode.sym));
    Buffer += sizeof(UINT16);
    break;
  case TPM_ALG_XOR:
    WriteUnaligned16 ((UINT16 *)Buffer, SwapBytes16 (Symmetric->keyBits.xor));
    Buffer += sizeof(UINT16);
    break;
  default:
    ASSERT (FALSE);
    DEBUG ((EFI_D_ERROR, "Tpm2StartAuthSession - Symmetric->algorithm - %x\n", Symmetric->algorithm));
    return EFI_UNSUPPORTED;
  }

  WriteUnaligned16 ((UINT16 *)Buffer, SwapBytes16 (AuthHash));
  Buffer += sizeof(UINT16);
 
  SendBufferSize = (UINT32) ((UINTN)Buffer - (UINTN)&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, "Tpm2StartAuthSession - RecvBufferSize Error - %x\n", RecvBufferSize));
    return EFI_DEVICE_ERROR;
  }
  if (SwapBytes32(RecvBuffer.Header.responseCode) != TPM_RC_SUCCESS) {
    DEBUG ((EFI_D_ERROR, "Tpm2StartAuthSession - responseCode - %x\n", SwapBytes32(RecvBuffer.Header.responseCode)));
    return EFI_DEVICE_ERROR;
  }

  //
  // Return the response
  //
  *SessionHandle = SwapBytes32 (RecvBuffer.SessionHandle);
  NonceTPM->size = SwapBytes16 (RecvBuffer.NonceTPM.size);
  CopyMem (NonceTPM->buffer, &RecvBuffer.NonceTPM.buffer, NonceTPM->size);

  return EFI_SUCCESS;
}