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3aa8dc6c LQ |
1 | /** @file\r |
2 | Support routines for RDRAND instruction access.\r | |
3 | \r | |
b3548d32 | 4 | Copyright (c) 2013 - 2018, Intel Corporation. All rights reserved.<BR>\r |
3b60842c | 5 | (C) Copyright 2015 Hewlett Packard Enterprise Development LP<BR>\r |
289b714b | 6 | SPDX-License-Identifier: BSD-2-Clause-Patent\r |
3aa8dc6c LQ |
7 | \r |
8 | **/\r | |
3b60842c | 9 | #include <Library/RngLib.h>\r |
3aa8dc6c LQ |
10 | \r |
11 | #include "RdRand.h"\r | |
12 | #include "AesCore.h"\r | |
13 | \r | |
3aa8dc6c LQ |
14 | /**\r |
15 | Calls RDRAND to fill a buffer of arbitrary size with random bytes.\r | |
16 | \r | |
17 | @param[in] Length Size of the buffer, in bytes, to fill with.\r | |
18 | @param[out] RandBuffer Pointer to the buffer to store the random result.\r | |
19 | \r | |
20 | @retval EFI_SUCCESS Random bytes generation succeeded.\r | |
21 | @retval EFI_NOT_READY Failed to request random bytes.\r | |
22 | \r | |
23 | **/\r | |
24 | EFI_STATUS\r | |
25 | EFIAPI\r | |
26 | RdRandGetBytes (\r | |
27 | IN UINTN Length,\r | |
28 | OUT UINT8 *RandBuffer\r | |
29 | )\r | |
30 | {\r | |
3b60842c TP |
31 | BOOLEAN IsRandom;\r |
32 | UINT64 TempRand[2];\r | |
3aa8dc6c | 33 | \r |
3b60842c TP |
34 | while (Length > 0) {\r |
35 | IsRandom = GetRandomNumber128 (TempRand);\r | |
36 | if (!IsRandom) {\r | |
37 | return EFI_NOT_READY;\r | |
3aa8dc6c | 38 | }\r |
3b60842c TP |
39 | if (Length >= sizeof (TempRand)) {\r |
40 | WriteUnaligned64 ((UINT64*)RandBuffer, TempRand[0]);\r | |
41 | RandBuffer += sizeof (UINT64);\r | |
42 | WriteUnaligned64 ((UINT64*)RandBuffer, TempRand[1]);\r | |
43 | RandBuffer += sizeof (UINT64);\r | |
44 | Length -= sizeof (TempRand);\r | |
45 | } else {\r | |
46 | CopyMem (RandBuffer, TempRand, Length);\r | |
47 | Length = 0;\r | |
3aa8dc6c LQ |
48 | }\r |
49 | }\r | |
50 | \r | |
51 | return EFI_SUCCESS;\r | |
52 | }\r | |
53 | \r | |
54 | /**\r | |
55 | Creates a 128bit random value that is fully forward and backward prediction resistant,\r | |
56 | suitable for seeding a NIST SP800-90 Compliant, FIPS 1402-2 certifiable SW DRBG.\r | |
57 | This function takes multiple random numbers through RDRAND without intervening\r | |
58 | delays to ensure reseeding and performs AES-CBC-MAC over the data to compute the\r | |
59 | seed value.\r | |
b3548d32 | 60 | \r |
3aa8dc6c LQ |
61 | @param[out] SeedBuffer Pointer to a 128bit buffer to store the random seed.\r |
62 | \r | |
63 | @retval EFI_SUCCESS Random seed generation succeeded.\r | |
64 | @retval EFI_NOT_READY Failed to request random bytes.\r | |
65 | \r | |
66 | **/\r | |
67 | EFI_STATUS\r | |
68 | EFIAPI\r | |
69 | RdRandGetSeed128 (\r | |
70 | OUT UINT8 *SeedBuffer\r | |
71 | )\r | |
72 | {\r | |
73 | EFI_STATUS Status;\r | |
74 | UINT8 RandByte[16];\r | |
75 | UINT8 Key[16];\r | |
76 | UINT8 Ffv[16];\r | |
77 | UINT8 Xored[16];\r | |
78 | UINT32 Index;\r | |
79 | UINT32 Index2;\r | |
80 | \r | |
81 | //\r | |
82 | // Chose an arbitary key and zero the feed_forward_value (FFV)\r | |
83 | //\r | |
84 | for (Index = 0; Index < 16; Index++) {\r | |
85 | Key[Index] = (UINT8) Index;\r | |
86 | Ffv[Index] = 0;\r | |
87 | }\r | |
88 | \r | |
89 | //\r | |
90 | // Perform CBC_MAC over 32 * 128 bit values, with 10us gaps between 128 bit value\r | |
91 | // The 10us gaps will ensure multiple reseeds within the HW RNG with a large design margin.\r | |
92 | //\r | |
93 | for (Index = 0; Index < 32; Index++) {\r | |
94 | MicroSecondDelay (10);\r | |
95 | Status = RdRandGetBytes (16, RandByte);\r | |
96 | if (EFI_ERROR (Status)) {\r | |
97 | return Status;\r | |
98 | }\r | |
99 | \r | |
100 | //\r | |
101 | // Perform XOR operations on two 128-bit value.\r | |
102 | //\r | |
103 | for (Index2 = 0; Index2 < 16; Index2++) {\r | |
104 | Xored[Index2] = RandByte[Index2] ^ Ffv[Index2];\r | |
105 | }\r | |
106 | \r | |
107 | AesEncrypt (Key, Xored, Ffv);\r | |
108 | }\r | |
109 | \r | |
110 | for (Index = 0; Index < 16; Index++) {\r | |
111 | SeedBuffer[Index] = Ffv[Index];\r | |
112 | }\r | |
113 | \r | |
114 | return EFI_SUCCESS;\r | |
115 | }\r | |
116 | \r | |
117 | /**\r | |
118 | Generate high-quality entropy source through RDRAND.\r | |
119 | \r | |
120 | @param[in] Length Size of the buffer, in bytes, to fill with.\r | |
121 | @param[out] Entropy Pointer to the buffer to store the entropy data.\r | |
122 | \r | |
123 | @retval EFI_SUCCESS Entropy generation succeeded.\r | |
124 | @retval EFI_NOT_READY Failed to request random data.\r | |
125 | \r | |
126 | **/\r | |
127 | EFI_STATUS\r | |
128 | EFIAPI\r | |
129 | RdRandGenerateEntropy (\r | |
130 | IN UINTN Length,\r | |
131 | OUT UINT8 *Entropy\r | |
132 | )\r | |
133 | {\r | |
134 | EFI_STATUS Status;\r | |
135 | UINTN BlockCount;\r | |
136 | UINT8 Seed[16];\r | |
137 | UINT8 *Ptr;\r | |
138 | \r | |
139 | Status = EFI_NOT_READY;\r | |
140 | BlockCount = Length / 16;\r | |
141 | Ptr = (UINT8 *)Entropy;\r | |
142 | \r | |
143 | //\r | |
144 | // Generate high-quality seed for DRBG Entropy\r | |
145 | //\r | |
146 | while (BlockCount > 0) {\r | |
147 | Status = RdRandGetSeed128 (Seed);\r | |
148 | if (EFI_ERROR (Status)) {\r | |
149 | return Status;\r | |
150 | }\r | |
151 | CopyMem (Ptr, Seed, 16);\r | |
152 | \r | |
153 | BlockCount--;\r | |
154 | Ptr = Ptr + 16;\r | |
155 | }\r | |
156 | \r | |
157 | //\r | |
158 | // Populate the remained data as request.\r | |
159 | //\r | |
160 | Status = RdRandGetSeed128 (Seed);\r | |
161 | if (EFI_ERROR (Status)) {\r | |
162 | return Status;\r | |
163 | }\r | |
164 | CopyMem (Ptr, Seed, (Length % 16));\r | |
165 | \r | |
166 | return Status;\r | |
167 | }\r |