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1 | /** @file\r |
2 | Pseudorandom Number Generator Wrapper Implementation over OpenSSL.\r |
3 | \r |
4 | Copyright (c) 2012, Intel Corporation. All rights reserved.<BR>\r |
5 | This program and the accompanying materials\r |
6 | are licensed and made available under the terms and conditions of the BSD License\r |
7 | which accompanies this distribution. The full text of the license may be found at\r |
8 | http://opensource.org/licenses/bsd-license.php\r |
9 | \r |
10 | THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r |
11 | WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r |
12 | \r |
13 | **/\r |
14 | \r |
15 | #include "InternalCryptLib.h"\r |
16 | #include <openssl/rand.h>\r |
17 | #include <Library/PrintLib.h>\r |
18 | \r |
19 | /**\r |
20 | Sets up the seed value for the pseudorandom number generator.\r |
21 | \r |
22 | This function sets up the seed value for the pseudorandom number generator.\r |
23 | If Seed is not NULL, then the seed passed in is used.\r |
24 | If Seed is NULL, then default seed is used.\r |
25 | \r |
26 | @param[in] Seed Pointer to seed value.\r |
27 | If NULL, default seed is used.\r |
28 | @param[in] SeedSize Size of seed value.\r |
29 | If Seed is NULL, this parameter is ignored.\r |
30 | \r |
31 | @retval TRUE Pseudorandom number generator has enough entropy for random generation.\r |
32 | @retval FALSE Pseudorandom number generator does not have enough entropy for random generation.\r |
33 | \r |
34 | **/\r |
35 | BOOLEAN\r |
36 | EFIAPI\r |
37 | RandomSeed (\r |
38 | IN CONST UINT8 *Seed OPTIONAL,\r |
39 | IN UINTN SeedSize\r |
40 | )\r |
41 | {\r |
42 | CHAR8 DefaultSeed[128];\r |
43 | \r |
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44 | if (SeedSize > INT_MAX) {\r |
45 | return FALSE;\r |
46 | }\r |
47 | \r |
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48 | //\r |
49 | // Seed the pseudorandom number generator with user-supplied value.\r |
50 | // NOTE: A cryptographic PRNG must be seeded with unpredictable data.\r |
51 | //\r |
52 | if (Seed != NULL) {\r |
53 | RAND_seed (Seed, (UINT32) SeedSize);\r |
54 | } else {\r |
55 | //\r |
56 | // Retrieve current time.\r |
57 | //\r |
58 | AsciiSPrint (\r |
59 | DefaultSeed,\r |
60 | sizeof (DefaultSeed),\r |
61 | "UEFI Crypto Library default seed (%ld)",\r |
62 | AsmReadItc ()\r |
63 | ); \r |
64 | \r |
65 | RAND_seed (DefaultSeed, sizeof (DefaultSeed));\r |
66 | }\r |
67 | \r |
68 | return TRUE;\r |
69 | }\r |
70 | \r |
71 | /**\r |
72 | Generates a pseudorandom byte stream of the specified size.\r |
73 | \r |
74 | If Output is NULL, then return FALSE.\r |
75 | \r |
76 | @param[out] Output Pointer to buffer to receive random value.\r |
77 | @param[in] Size Size of randome bytes to generate.\r |
78 | \r |
79 | @retval TRUE Pseudorandom byte stream generated successfully.\r |
80 | @retval FALSE Pseudorandom number generator fails to generate due to lack of entropy.\r |
81 | \r |
82 | **/\r |
83 | BOOLEAN\r |
84 | EFIAPI\r |
85 | RandomBytes (\r |
86 | OUT UINT8 *Output,\r |
87 | IN UINTN Size\r |
88 | )\r |
89 | {\r |
90 | //\r |
91 | // Check input parameters.\r |
92 | //\r |
dda39f3a |
93 | if (Output == NULL || Size > INT_MAX) {\r |
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94 | return FALSE;\r |
95 | }\r |
96 | \r |
97 | //\r |
98 | // Generate random data.\r |
99 | //\r |
100 | if (RAND_bytes (Output, (UINT32) Size) != 1) {\r |
101 | return FALSE;\r |
102 | }\r |
103 | \r |
104 | return TRUE;\r |
105 | }\r |