1 // This file was extracted from the TCG Published 2 // Trusted Platform Module Library 3 // Part 3: Commands 4 // Family "2.0" 5 // Level 00 Revision 01.16 6 // October 30, 2014 7 8 #include "InternalRoutines.h" 9 #include "StartAuthSession_fp.h" 10 // 11 // 12 // Error Returns Meaning 13 // 14 // TPM_RC_ATTRIBUTES tpmKey does not reference a decrypt key 15 // TPM_RC_CONTEXT_GAP the difference between the most recently created active context and 16 // the oldest active context is at the limits of the TPM 17 // TPM_RC_HANDLE input decrypt key handle only has public portion loaded 18 // TPM_RC_MODE symmetric specifies a block cipher but the mode is not 19 // TPM_ALG_CFB. 20 // TPM_RC_SESSION_HANDLES no session handle is available 21 // TPM_RC_SESSION_MEMORY no more slots for loading a session 22 // TPM_RC_SIZE nonce less than 16 octets or greater than the size of the digest 23 // produced by authHash 24 // TPM_RC_VALUE secret size does not match decrypt key type; or the recovered secret 25 // is larger than the digest size of the nameAlg of tpmKey; or, for an 26 // RSA decrypt key, if encryptedSecret is greater than the public 27 // exponent of tpmKey. 28 // 29 TPM_RC 30 TPM2_StartAuthSession( 31 StartAuthSession_In *in, // IN: input parameter buffer 32 StartAuthSession_Out *out // OUT: output parameter buffer 33 ) 34 { 35 TPM_RC result = TPM_RC_SUCCESS; 36 OBJECT *tpmKey; // TPM key for decrypt salt 37 SESSION *session; // session internal data 38 TPM2B_DATA salt; 39 40 // Input Validation 41 42 // Check input nonce size. IT should be at least 16 bytes but not larger 43 // than the digest size of session hash. 44 if( in->nonceCaller.t.size < 16 45 || in->nonceCaller.t.size > CryptGetHashDigestSize(in->authHash)) 46 return TPM_RC_SIZE + RC_StartAuthSession_nonceCaller; 47 48 // If an decrypt key is passed in, check its validation 49 if(in->tpmKey != TPM_RH_NULL) 50 { 51 // secret size cannot be 0 52 if(in->encryptedSalt.t.size == 0) 53 return TPM_RC_VALUE + RC_StartAuthSession_encryptedSalt; 54 55 // Get pointer to loaded decrypt key 56 tpmKey = ObjectGet(in->tpmKey); 57 58 // Decrypting salt requires accessing the private portion of a key. 59 // Therefore, tmpKey can not be a key with only public portion loaded 60 if(tpmKey->attributes.publicOnly) 61 return TPM_RC_HANDLE + RC_StartAuthSession_tpmKey; 62 63 // HMAC session input handle check. 64 // tpmKey should be a decryption key 65 if(tpmKey->publicArea.objectAttributes.decrypt != SET) 66 return TPM_RC_ATTRIBUTES + RC_StartAuthSession_tpmKey; 67 68 // Secret Decryption. A TPM_RC_VALUE, TPM_RC_KEY or Unmarshal errors 69 // may be returned at this point 70 result = CryptSecretDecrypt(in->tpmKey, &in->nonceCaller, "SECRET", 71 &in->encryptedSalt, &salt); 72 if(result != TPM_RC_SUCCESS) 73 return TPM_RC_VALUE + RC_StartAuthSession_encryptedSalt; 74 75 } 76 else 77 { 78 // secret size must be 0 79 if(in->encryptedSalt.t.size != 0) 80 return TPM_RC_VALUE + RC_StartAuthSession_encryptedSalt; 81 salt.t.size = 0; 82 } 83 // If the bind handle references a transient object, make sure that the 84 // sensitive area is loaded so that the authValue can be accessed. 85 if( HandleGetType(in->bind) == TPM_HT_TRANSIENT 86 && ObjectGet(in->bind)->attributes.publicOnly == SET) 87 return TPM_RC_HANDLE + RC_StartAuthSession_bind; 88 89 // If 'symmetric' is a symmetric block cipher (not TPM_ALG_NULL or TPM_ALG_XOR) 90 // then the mode must be CFB. 91 if( in->symmetric.algorithm != TPM_ALG_NULL 92 && in->symmetric.algorithm != TPM_ALG_XOR 93 && in->symmetric.mode.sym != TPM_ALG_CFB) 94 return TPM_RC_MODE + RC_StartAuthSession_symmetric; 95 96 // Internal Data Update 97 98 // Create internal session structure. TPM_RC_CONTEXT_GAP, TPM_RC_NO_HANDLES 99 // or TPM_RC_SESSION_MEMORY errors may be returned returned at this point. 100 // 101 // The detailed actions for creating the session context are not shown here 102 // as the details are implementation dependent 103 // SessionCreate sets the output handle 104 result = SessionCreate(in->sessionType, in->authHash, 105 &in->nonceCaller, &in->symmetric, 106 in->bind, &salt, &out->sessionHandle); 107 108 if(result != TPM_RC_SUCCESS) 109 return result; 110 111 // Command Output 112 113 // Get session pointer 114 session = SessionGet(out->sessionHandle); 115 116 // Copy nonceTPM 117 out->nonceTPM = session->nonceTPM; 118 119 return TPM_RC_SUCCESS; 120 } 121
