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 //** Introduction
36 // In some implementations of the TPM, the hardware can provide a secret
37 // value to the TPM. This secret value is statistically unique to the
38 // instance of the TPM. Typical uses of this value are to provide
39 // personalization to the random number generation and as a shared secret
40 // between the TPM and the manufacturer.
41
42 //** Includes
43 #include "PlatformData.h"
44 #include "Platform_fp.h"
45
46 #include <tee_internal_api.h>
47 #include <assert.h>
48
49 //static TEE_UUID deviceUniqueValue = { 0 };
50 static char *deviceUniqueValue[sizeof(TEE_UUID)+1];
51 static bool initializedUniqueValue = false;
52
53 //** _plat__GetUnique()
54 // This function is used to access the platform-specific unique value.
55 // This function places the unique value in the provided buffer ('b')
56 // and returns the number of bytes transferred. The function will not
57 // copy more data than 'bSize'.
58 // NOTE: If a platform unique value has unequal distribution of uniqueness
59 // and 'bSize' is smaller than the size of the unique value, the 'bSize'
60 // portion with the most uniqueness should be returned.
61 LIB_EXPORT uint32_t
_plat__GetUnique(uint32_t which,uint32_t bSize,unsigned char * b)62 _plat__GetUnique(
63 uint32_t which, // authorities (0) or details
64 uint32_t bSize, // size of the buffer
65 unsigned char *b // output buffer
66 )
67 {
68 const char *from = (char *)&deviceUniqueValue;
69 uint32_t uSize = sizeof(TEE_UUID) + 1;
70 uint32_t retVal = 0;
71 TEE_Result teeResult;
72
73 // Check if we've initialized our unique platform value.
74 if (!initializedUniqueValue) {
75 teeResult = TEE_GetPropertyAsUUID(TEE_PROPSET_TEE_IMPLEMENTATION,
76 "gpd.tee.deviceID",
77 (TEE_UUID*)&deviceUniqueValue);
78 assert(teeResult == TEE_SUCCESS);
79 }
80 deviceUniqueValue[uSize-1] = '\0';
81
82 if(which == 0) // the authorities value
83 {
84 for(retVal = 0;
85 *from != 0 && retVal < bSize;
86 retVal++)
87 {
88 *b++ = *from++;
89 }
90 }
91 else
92 {
93 b = &b[((bSize < uSize) ? bSize : uSize) - 1];
94 for(retVal = 0;
95 *from != 0 && retVal < bSize;
96 retVal++)
97 {
98 *b-- = *from++;
99 }
100 }
101 return retVal;
102 }