1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
|
// 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 "ContextSave_fp.h"
#include "Context_spt_fp.h"
//
//
// Error Returns Meaning
//
// TPM_RC_CONTEXT_GAP a contextID could not be assigned for a session context save
// TPM_RC_TOO_MANY_CONTEXTS no more contexts can be saved as the counter has maxed out
//
TPM_RC
TPM2_ContextSave(
ContextSave_In *in, // IN: input parameter list
ContextSave_Out *out // OUT: output parameter list
)
{
TPM_RC result;
UINT16 fingerprintSize; // The size of fingerprint in context
// blob.
UINT64 contextID = 0; // session context ID
TPM2B_SYM_KEY symKey;
TPM2B_IV iv;
TPM2B_DIGEST integrity;
UINT16 integritySize;
BYTE *buffer;
INT32 bufferSize;
// This command may cause the orderlyState to be cleared due to
// the update of state reset data. If this is the case, check if NV is
// available first
if(gp.orderlyState != SHUTDOWN_NONE)
{
// The command needs NV update. Check if NV is available.
// A TPM_RC_NV_UNAVAILABLE or TPM_RC_NV_RATE error may be returned at
// this point
result = NvIsAvailable();
if(result != TPM_RC_SUCCESS) return result;
}
// Internal Data Update
// Initialize output handle. At the end of command action, the output
// handle of an object will be replaced, while the output handle
// for a session will be the same as input
out->context.savedHandle = in->saveHandle;
// Get the size of fingerprint in context blob. The sequence value in
// TPMS_CONTEXT structure is used as the fingerprint
fingerprintSize = sizeof(out->context.sequence);
// Compute the integrity size at the beginning of context blob
integritySize = sizeof(integrity.t.size)
+ CryptGetHashDigestSize(CONTEXT_INTEGRITY_HASH_ALG);
// Perform object or session specific context save
switch(HandleGetType(in->saveHandle))
{
case TPM_HT_TRANSIENT:
{
OBJECT *object = ObjectGet(in->saveHandle);
OBJECT *outObject =
(OBJECT *)(out->context.contextBlob.t.buffer
+ integritySize + fingerprintSize);
// Set size of the context data. The contents of context blob is vendor
// defined. In this implementation, the size is size of integrity
// plus fingerprint plus the whole internal OBJECT structure
out->context.contextBlob.t.size = integritySize +
fingerprintSize + sizeof(OBJECT);
// Make sure things fit
pAssert(out->context.contextBlob.t.size
< sizeof(out->context.contextBlob.t.buffer));
// Copy the whole internal OBJECT structure to context blob, leave
// the size for fingerprint
*outObject = *object;
// Increment object context ID
gr.objectContextID++;
// If object context ID overflows, TPM should be put in failure mode
if(gr.objectContextID == 0)
FAIL(FATAL_ERROR_INTERNAL);
// Fill in other return values for an object.
out->context.sequence = gr.objectContextID;
// For regular object, savedHandle is 0x80000000. For sequence object,
// savedHandle is 0x80000001. For object with stClear, savedHandle
// is 0x80000002
if(ObjectIsSequence(object))
{
out->context.savedHandle = 0x80000001;
SequenceDataImportExport(object, outObject, EXPORT_STATE);
}
else if(object->attributes.stClear == SET)
{
out->context.savedHandle = 0x80000002;
}
else
{
out->context.savedHandle = 0x80000000;
}
// Get object hierarchy
out->context.hierarchy = ObjectDataGetHierarchy(object);
break;
}
case TPM_HT_HMAC_SESSION:
case TPM_HT_POLICY_SESSION:
{
SESSION *session = SessionGet(in->saveHandle);
// Set size of the context data. The contents of context blob is vendor
// defined. In this implementation, the size of context blob is the
// size of a internal session structure plus the size of
// fingerprint plus the size of integrity
out->context.contextBlob.t.size = integritySize +
fingerprintSize + sizeof(*session);
// Make sure things fit
pAssert(out->context.contextBlob.t.size
< sizeof(out->context.contextBlob.t.buffer));
// Copy the whole internal SESSION structure to context blob.
// Save space for fingerprint at the beginning of the buffer
// This is done before anything else so that the actual context
// can be reclaimed after this call
MemoryCopy(out->context.contextBlob.t.buffer
+ integritySize + fingerprintSize,
session, sizeof(*session),
sizeof(out->context.contextBlob.t.buffer)
- integritySize - fingerprintSize);
// Fill in the other return parameters for a session
// Get a context ID and set the session tracking values appropriately
// TPM_RC_CONTEXT_GAP is a possible error.
// SessionContextSave() will flush the in-memory context
// so no additional errors may occur after this call.
result = SessionContextSave(out->context.savedHandle, &contextID);
if(result != TPM_RC_SUCCESS) return result;
// sequence number is the current session contextID
out->context.sequence = contextID;
// use TPM_RH_NULL as hierarchy for session context
out->context.hierarchy = TPM_RH_NULL;
break;
}
default:
// SaveContext may only take an object handle or a session handle.
// All the other handle type should be filtered out at unmarshal
pAssert(FALSE);
break;
}
// Save fingerprint at the beginning of encrypted area of context blob.
// Reserve the integrity space
MemoryCopy(out->context.contextBlob.t.buffer + integritySize,
&out->context.sequence, sizeof(out->context.sequence),
sizeof(out->context.contextBlob.t.buffer) - integritySize);
// Compute context encryption key
ComputeContextProtectionKey(&out->context, &symKey, &iv);
// Encrypt context blob
CryptSymmetricEncrypt(out->context.contextBlob.t.buffer + integritySize,
CONTEXT_ENCRYPT_ALG, CONTEXT_ENCRYPT_KEY_BITS,
TPM_ALG_CFB, symKey.t.buffer, &iv,
out->context.contextBlob.t.size - integritySize,
out->context.contextBlob.t.buffer + integritySize);
// Compute integrity hash for the object
// In this implementation, the same routine is used for both sessions
// and objects.
ComputeContextIntegrity(&out->context, &integrity);
// add integrity at the beginning of context blob
buffer = out->context.contextBlob.t.buffer;
bufferSize = sizeof(TPM2B_DIGEST);
TPM2B_DIGEST_Marshal(&integrity, &buffer, &bufferSize);
// orderly state should be cleared because of the update of state reset and
// state clear data
g_clearOrderly = TRUE;
return TPM_RC_SUCCESS;
}
|
