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 "HMAC_Start_fp.h"
10//
11//
12//     Error Returns                     Meaning
13//
14//     TPM_RC_ATTRIBUTES                 key referenced by handle is not a signing key or is restricted
15//     TPM_RC_OBJECT_MEMORY              no space to create an internal object
16//     TPM_RC_KEY                        key referenced by handle is not an HMAC key
17//     TPM_RC_VALUE                      hashAlg is not compatible with the hash algorithm of the scheme of
18//                                       the object referenced by handle
19//
20TPM_RC
21TPM2_HMAC_Start(
22   HMAC_Start_In     *in,                 // IN: input parameter list
23   HMAC_Start_Out    *out                 // OUT: output parameter list
24   )
25{
26   OBJECT                    *hmacObject;
27   TPMT_PUBLIC               *publicArea;
28   TPM_ALG_ID                 hashAlg;
29
30// Input Validation
31
32   // Get HMAC key object and public area pointers
33   hmacObject = ObjectGet(in->handle);
34   publicArea = &hmacObject->publicArea;
35
36   // Make sure that the key is an HMAC key
37   if(publicArea->type != TPM_ALG_KEYEDHASH)
38       return TPM_RC_TYPE + RC_HMAC_Start_handle;
39
40   // and that it is unrestricted
41   if(publicArea->objectAttributes.restricted == SET)
42       return TPM_RC_ATTRIBUTES + RC_HMAC_Start_handle;
43
44   // and that it is a signing key
45   if(publicArea->objectAttributes.sign != SET)
46       return TPM_RC_KEY + RC_HMAC_Start_handle;
47
48   // See if the key has a default
49   if(publicArea->parameters.keyedHashDetail.scheme.scheme == TPM_ALG_NULL)
50       // it doesn't so use the input value
51       hashAlg = in->hashAlg;
52   else
53   {
54       // key has a default so use it
55       hashAlg
56           = publicArea->parameters.keyedHashDetail.scheme.details.hmac.hashAlg;
57       // and verify that the input was either the TPM_ALG_NULL or the default
58       if(in->hashAlg != TPM_ALG_NULL && in->hashAlg != hashAlg)
59           hashAlg = TPM_ALG_NULL;
60   }
61   // if we ended up without a hash algorith then return an error
62   if(hashAlg == TPM_ALG_NULL)
63       return TPM_RC_VALUE + RC_HMAC_Start_hashAlg;
64
65// Internal Data Update
66
67  // Create a HMAC sequence object. A TPM_RC_OBJECT_MEMORY error may be
68  // returned at this point
69  return ObjectCreateHMACSequence(hashAlg,
70                                  in->handle,
71                                  &in->auth,
72                                  &out->sequenceHandle);
73}
74