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3aa8dc6c LQ |
1 | /** @file\r |
2 | Support routines for RDRAND instruction access.\r | |
3 | \r | |
4 | Copyright (c) 2013, Intel Corporation. All rights reserved.<BR>\r | |
3b60842c | 5 | (C) Copyright 2015 Hewlett Packard Enterprise Development LP<BR>\r |
3aa8dc6c LQ |
6 | This program and the accompanying materials\r |
7 | are licensed and made available under the terms and conditions of the BSD License\r | |
8 | which accompanies this distribution. The full text of the license may be found at\r | |
9 | http://opensource.org/licenses/bsd-license.php\r | |
10 | \r | |
11 | THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r | |
12 | WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r | |
13 | \r | |
14 | **/\r | |
3b60842c | 15 | #include <Library/RngLib.h>\r |
3aa8dc6c LQ |
16 | \r |
17 | #include "RdRand.h"\r | |
18 | #include "AesCore.h"\r | |
19 | \r | |
3aa8dc6c LQ |
20 | /**\r |
21 | Calls RDRAND to fill a buffer of arbitrary size with random bytes.\r | |
22 | \r | |
23 | @param[in] Length Size of the buffer, in bytes, to fill with.\r | |
24 | @param[out] RandBuffer Pointer to the buffer to store the random result.\r | |
25 | \r | |
26 | @retval EFI_SUCCESS Random bytes generation succeeded.\r | |
27 | @retval EFI_NOT_READY Failed to request random bytes.\r | |
28 | \r | |
29 | **/\r | |
30 | EFI_STATUS\r | |
31 | EFIAPI\r | |
32 | RdRandGetBytes (\r | |
33 | IN UINTN Length,\r | |
34 | OUT UINT8 *RandBuffer\r | |
35 | )\r | |
36 | {\r | |
3b60842c TP |
37 | BOOLEAN IsRandom;\r |
38 | UINT64 TempRand[2];\r | |
3aa8dc6c | 39 | \r |
3b60842c TP |
40 | while (Length > 0) {\r |
41 | IsRandom = GetRandomNumber128 (TempRand);\r | |
42 | if (!IsRandom) {\r | |
43 | return EFI_NOT_READY;\r | |
3aa8dc6c | 44 | }\r |
3b60842c TP |
45 | if (Length >= sizeof (TempRand)) {\r |
46 | WriteUnaligned64 ((UINT64*)RandBuffer, TempRand[0]);\r | |
47 | RandBuffer += sizeof (UINT64);\r | |
48 | WriteUnaligned64 ((UINT64*)RandBuffer, TempRand[1]);\r | |
49 | RandBuffer += sizeof (UINT64);\r | |
50 | Length -= sizeof (TempRand);\r | |
51 | } else {\r | |
52 | CopyMem (RandBuffer, TempRand, Length);\r | |
53 | Length = 0;\r | |
3aa8dc6c LQ |
54 | }\r |
55 | }\r | |
56 | \r | |
57 | return EFI_SUCCESS;\r | |
58 | }\r | |
59 | \r | |
60 | /**\r | |
61 | Creates a 128bit random value that is fully forward and backward prediction resistant,\r | |
62 | suitable for seeding a NIST SP800-90 Compliant, FIPS 1402-2 certifiable SW DRBG.\r | |
63 | This function takes multiple random numbers through RDRAND without intervening\r | |
64 | delays to ensure reseeding and performs AES-CBC-MAC over the data to compute the\r | |
65 | seed value.\r | |
66 | \r | |
67 | @param[out] SeedBuffer Pointer to a 128bit buffer to store the random seed.\r | |
68 | \r | |
69 | @retval EFI_SUCCESS Random seed generation succeeded.\r | |
70 | @retval EFI_NOT_READY Failed to request random bytes.\r | |
71 | \r | |
72 | **/\r | |
73 | EFI_STATUS\r | |
74 | EFIAPI\r | |
75 | RdRandGetSeed128 (\r | |
76 | OUT UINT8 *SeedBuffer\r | |
77 | )\r | |
78 | {\r | |
79 | EFI_STATUS Status;\r | |
80 | UINT8 RandByte[16];\r | |
81 | UINT8 Key[16];\r | |
82 | UINT8 Ffv[16];\r | |
83 | UINT8 Xored[16];\r | |
84 | UINT32 Index;\r | |
85 | UINT32 Index2;\r | |
86 | \r | |
87 | //\r | |
88 | // Chose an arbitary key and zero the feed_forward_value (FFV)\r | |
89 | //\r | |
90 | for (Index = 0; Index < 16; Index++) {\r | |
91 | Key[Index] = (UINT8) Index;\r | |
92 | Ffv[Index] = 0;\r | |
93 | }\r | |
94 | \r | |
95 | //\r | |
96 | // Perform CBC_MAC over 32 * 128 bit values, with 10us gaps between 128 bit value\r | |
97 | // The 10us gaps will ensure multiple reseeds within the HW RNG with a large design margin.\r | |
98 | //\r | |
99 | for (Index = 0; Index < 32; Index++) {\r | |
100 | MicroSecondDelay (10);\r | |
101 | Status = RdRandGetBytes (16, RandByte);\r | |
102 | if (EFI_ERROR (Status)) {\r | |
103 | return Status;\r | |
104 | }\r | |
105 | \r | |
106 | //\r | |
107 | // Perform XOR operations on two 128-bit value.\r | |
108 | //\r | |
109 | for (Index2 = 0; Index2 < 16; Index2++) {\r | |
110 | Xored[Index2] = RandByte[Index2] ^ Ffv[Index2];\r | |
111 | }\r | |
112 | \r | |
113 | AesEncrypt (Key, Xored, Ffv);\r | |
114 | }\r | |
115 | \r | |
116 | for (Index = 0; Index < 16; Index++) {\r | |
117 | SeedBuffer[Index] = Ffv[Index];\r | |
118 | }\r | |
119 | \r | |
120 | return EFI_SUCCESS;\r | |
121 | }\r | |
122 | \r | |
123 | /**\r | |
124 | Generate high-quality entropy source through RDRAND.\r | |
125 | \r | |
126 | @param[in] Length Size of the buffer, in bytes, to fill with.\r | |
127 | @param[out] Entropy Pointer to the buffer to store the entropy data.\r | |
128 | \r | |
129 | @retval EFI_SUCCESS Entropy generation succeeded.\r | |
130 | @retval EFI_NOT_READY Failed to request random data.\r | |
131 | \r | |
132 | **/\r | |
133 | EFI_STATUS\r | |
134 | EFIAPI\r | |
135 | RdRandGenerateEntropy (\r | |
136 | IN UINTN Length,\r | |
137 | OUT UINT8 *Entropy\r | |
138 | )\r | |
139 | {\r | |
140 | EFI_STATUS Status;\r | |
141 | UINTN BlockCount;\r | |
142 | UINT8 Seed[16];\r | |
143 | UINT8 *Ptr;\r | |
144 | \r | |
145 | Status = EFI_NOT_READY;\r | |
146 | BlockCount = Length / 16;\r | |
147 | Ptr = (UINT8 *)Entropy;\r | |
148 | \r | |
149 | //\r | |
150 | // Generate high-quality seed for DRBG Entropy\r | |
151 | //\r | |
152 | while (BlockCount > 0) {\r | |
153 | Status = RdRandGetSeed128 (Seed);\r | |
154 | if (EFI_ERROR (Status)) {\r | |
155 | return Status;\r | |
156 | }\r | |
157 | CopyMem (Ptr, Seed, 16);\r | |
158 | \r | |
159 | BlockCount--;\r | |
160 | Ptr = Ptr + 16;\r | |
161 | }\r | |
162 | \r | |
163 | //\r | |
164 | // Populate the remained data as request.\r | |
165 | //\r | |
166 | Status = RdRandGetSeed128 (Seed);\r | |
167 | if (EFI_ERROR (Status)) {\r | |
168 | return Status;\r | |
169 | }\r | |
170 | CopyMem (Ptr, Seed, (Length % 16));\r | |
171 | \r | |
172 | return Status;\r | |
173 | }\r |