// This file was extracted from the TCG Published

// Trusted Platform Module Library

// Part 3: Commands

// Family "2.0"

// Level 00 Revision 01.16

// October 30, 2014

#include "InternalRoutines.h"

#include "RSA_Decrypt_fp.h"

#ifdef TPM_ALG_RSA

//

//

//     Error Returns                     Meaning

//

//     TPM_RC_ATTRIBUTES                 If the key is restricted or the key is not a decryption key

//     TPM_RC_BINDING                    The public an private parts of the key are not properly bound

//     TPM_RC_KEY                        keyHandle does not reference an unrestricted decrypt key

//     TPM_RC_SCHEME                     incorrect input scheme, or the chosen scheme is not a valid RSA

//                                       decrypt scheme

//     TPM_RC_SIZE                       cipherText is not the size of the modulus of key referenced by

//                                       keyHandle

//     TPM_RC_VALUE                      label is not a null terminated string or the value of cipherText is

//                                       greater that the modulus of keyHandle

//

TPM_RC

TPM2_RSA_Decrypt(

   RSA_Decrypt_In        *in,                   // IN: input parameter list

   RSA_Decrypt_Out       *out                   // OUT: output parameter list

   )

{

   TPM_RC                             result;

   OBJECT                            *rsaKey;

   TPMT_RSA_DECRYPT                  *scheme;

   char                              *label = NULL;

// Input Validation

   rsaKey = ObjectGet(in->keyHandle);

   // The selected key must be an RSA key

   if(rsaKey->publicArea.type != TPM_ALG_RSA)

       return TPM_RC_KEY + RC_RSA_Decrypt_keyHandle;

   // The selected key must be an unrestricted decryption key

   if(   rsaKey->publicArea.objectAttributes.restricted == SET

      || rsaKey->publicArea.objectAttributes.decrypt == CLEAR)

       return TPM_RC_ATTRIBUTES + RC_RSA_Decrypt_keyHandle;

   //   NOTE: Proper operation of this command requires that the sensitive area

   //   of the key is loaded. This is assured because authorization is required

   //   to use the sensitive area of the key. In order to check the authorization,

   //   the sensitive area has to be loaded, even if authorization is with policy.

   // If label is present, make sure that it is a NULL-terminated string

   if(in->label.t.size > 0)

   {

       // Present, so make sure that it is NULL-terminated

       if(in->label.t.buffer[in->label.t.size - 1] != 0)

           return TPM_RC_VALUE + RC_RSA_Decrypt_label;

       label = (char *)in->label.t.buffer;

   }

// Command Output

   // Select a scheme for decrypt.

   scheme = CryptSelectRSAScheme(in->keyHandle, &in->inScheme);

  if(scheme == NULL)

      return TPM_RC_SCHEME + RC_RSA_Decrypt_inScheme;

  // Decryption. TPM_RC_VALUE, TPM_RC_SIZE, and TPM_RC_KEY error may be

  // returned by CryptDecryptRSA.

  // NOTE: CryptDecryptRSA can also return TPM_RC_ATTRIBUTES or TPM_RC_BINDING

  // when the key is not a decryption key but that was checked above.

  out->message.t.size = sizeof(out->message.t.buffer);

  result = CryptDecryptRSA(&out->message.t.size, out->message.t.buffer, rsaKey,

                           scheme, in->cipherText.t.size,

                           in->cipherText.t.buffer,

                           label);

   return result;

}

#endif