1 /* Microsoft Reference Implementation for TPM 2.0
2 *
3 * The copyright in this software is being made available under the BSD License,
4 * included below. This software may be subject to other third party and
5 * contributor rights, including patent rights, and no such rights are granted
6 * under this license.
7 *
8 * Copyright (c) Microsoft Corporation
9 *
10 * All rights reserved.
11 *
12 * BSD License
13 *
14 * Redistribution and use in source and binary forms, with or without modification,
15 * are permitted provided that the following conditions are met:
16 *
17 * Redistributions of source code must retain the above copyright notice, this list
18 * of conditions and the following disclaimer.
19 *
20 * Redistributions in binary form must reproduce the above copyright notice, this
21 * list of conditions and the following disclaimer in the documentation and/or
22 * other materials provided with the distribution.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ""AS IS""
25 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
27 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
28 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
29 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
30 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
31 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
32 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
33 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34 */
35 #include "Tpm.h"
36 #include "ContextLoad_fp.h"
37
38 #if CC_ContextLoad // Conditional expansion of this file
39
40 #include "Context_spt_fp.h"
41
42 /*(See part 3 specification)
43 // Load context
44 */
45
46 // Return Type: TPM_RC
47 // TPM_RC_CONTEXT_GAP there is only one available slot and this is not
48 // the oldest saved session context
49 // TPM_RC_HANDLE 'context.savedHandle' does not reference a saved
50 // session
51 // TPM_RC_HIERARCHY 'context.hierarchy' is disabled
52 // TPM_RC_INTEGRITY 'context' integrity check fail
53 // TPM_RC_OBJECT_MEMORY no free slot for an object
54 // TPM_RC_SESSION_MEMORY no free session slots
55 // TPM_RC_SIZE incorrect context blob size
56 TPM_RC
TPM2_ContextLoad(ContextLoad_In * in,ContextLoad_Out * out)57 TPM2_ContextLoad(
58 ContextLoad_In *in, // IN: input parameter list
59 ContextLoad_Out *out // OUT: output parameter list
60 )
61 {
62 TPM_RC result;
63 TPM2B_DIGEST integrityToCompare;
64 TPM2B_DIGEST integrity;
65 BYTE *buffer; // defined to save some typing
66 INT32 size; // defined to save some typing
67 TPM_HT handleType;
68 TPM2B_SYM_KEY symKey;
69 TPM2B_IV iv;
70
71 // Input Validation
72
73 // See discussion about the context format in TPM2_ContextSave Detailed Actions
74
75 // IF this is a session context, make sure that the sequence number is
76 // consistent with the version in the slot
77
78 // Check context blob size
79 handleType = HandleGetType(in->context.savedHandle);
80
81 // Get integrity from context blob
82 buffer = in->context.contextBlob.t.buffer;
83 size = (INT32)in->context.contextBlob.t.size;
84 result = TPM2B_DIGEST_Unmarshal(&integrity, &buffer, &size);
85 if(result != TPM_RC_SUCCESS)
86 return result;
87
88 // the size of the integrity value has to match the size of digest produced
89 // by the integrity hash
90 if(integrity.t.size != CryptHashGetDigestSize(CONTEXT_INTEGRITY_HASH_ALG))
91 return TPM_RCS_SIZE + RC_ContextLoad_context;
92
93 // Make sure that the context blob has enough space for the fingerprint. This
94 // is elastic pants to go with the belt and suspenders we already have to make
95 // sure that the context is complete and untampered.
96 if((unsigned)size < sizeof(in->context.sequence))
97 return TPM_RCS_SIZE + RC_ContextLoad_context;
98
99 // After unmarshaling the integrity value, 'buffer' is pointing at the first
100 // byte of the integrity protected and encrypted buffer and 'size' is the number
101 // of integrity protected and encrypted bytes.
102
103 // Compute context integrity
104 ComputeContextIntegrity(&in->context, &integrityToCompare);
105
106 // Compare integrity
107 if(!MemoryEqual2B(&integrity.b, &integrityToCompare.b))
108 return TPM_RCS_INTEGRITY + RC_ContextLoad_context;
109 // Compute context encryption key
110 ComputeContextProtectionKey(&in->context, &symKey, &iv);
111
112 // Decrypt context data in place
113 CryptSymmetricDecrypt(buffer, CONTEXT_ENCRYPT_ALG, CONTEXT_ENCRYPT_KEY_BITS,
114 symKey.t.buffer, &iv, TPM_ALG_CFB, size, buffer);
115 // See if the fingerprint value matches. If not, it is symptomatic of either
116 // a broken TPM or that the TPM is under attack so go into failure mode.
117 if(!MemoryEqual(buffer, &in->context.sequence, sizeof(in->context.sequence)))
118 FAIL(FATAL_ERROR_INTERNAL);
119
120 // step over fingerprint
121 buffer += sizeof(in->context.sequence);
122
123 // set the remaining size of the context
124 size -= sizeof(in->context.sequence);
125
126 // Perform object or session specific input check
127 switch(handleType)
128 {
129 case TPM_HT_TRANSIENT:
130 {
131 OBJECT *outObject;
132
133 if(size > (INT32)sizeof(OBJECT))
134 FAIL(FATAL_ERROR_INTERNAL);
135
136 // Discard any changes to the handle that the TRM might have made
137 in->context.savedHandle = TRANSIENT_FIRST;
138
139 // If hierarchy is disabled, no object context can be loaded in this
140 // hierarchy
141 if(!HierarchyIsEnabled(in->context.hierarchy))
142 return TPM_RCS_HIERARCHY + RC_ContextLoad_context;
143
144 // Restore object. If there is no empty space, indicate as much
145 outObject = ObjectContextLoad((ANY_OBJECT_BUFFER *)buffer,
146 &out->loadedHandle);
147 if(outObject == NULL)
148 return TPM_RC_OBJECT_MEMORY;
149
150 break;
151 }
152 case TPM_HT_POLICY_SESSION:
153 case TPM_HT_HMAC_SESSION:
154 {
155 if(size != sizeof(SESSION))
156 FAIL(FATAL_ERROR_INTERNAL);
157
158 // This command may cause the orderlyState to be cleared due to
159 // the update of state reset data. If this is the case, check if NV is
160 // available first
161 RETURN_IF_ORDERLY;
162
163 // Check if input handle points to a valid saved session and that the
164 // sequence number makes sense
165 if(!SequenceNumberForSavedContextIsValid(&in->context))
166 return TPM_RCS_HANDLE + RC_ContextLoad_context;
167
168 // Restore session. A TPM_RC_SESSION_MEMORY, TPM_RC_CONTEXT_GAP error
169 // may be returned at this point
170 result = SessionContextLoad((SESSION_BUF *)buffer,
171 &in->context.savedHandle);
172 if(result != TPM_RC_SUCCESS)
173 return result;
174
175 out->loadedHandle = in->context.savedHandle;
176
177 // orderly state should be cleared because of the update of state
178 // reset and state clear data
179 g_clearOrderly = TRUE;
180
181 break;
182 }
183 default:
184 // Context blob may only have an object handle or a session handle.
185 // All the other handle type should be filtered out at unmarshal
186 FAIL(FATAL_ERROR_INTERNAL);
187 break;
188 }
189
190 return TPM_RC_SUCCESS;
191 }
192
193 #endif // CC_ContextLoad