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7ce960e7 | 1 | /** @file\r |
2 | Pseudorandom Number Generator Wrapper Implementation over OpenSSL.\r | |
3 | \r | |
38d91622 | 4 | Copyright (c) 2012 - 2013, Intel Corporation. All rights reserved.<BR>\r |
7ce960e7 | 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 | |
38d91622 | 17 | #include <openssl/evp.h>\r |
7ce960e7 | 18 | #include <Library/PrintLib.h>\r |
19 | \r | |
20 | /**\r | |
21 | Sets up the seed value for the pseudorandom number generator.\r | |
22 | \r | |
23 | This function sets up the seed value for the pseudorandom number generator.\r | |
24 | If Seed is not NULL, then the seed passed in is used.\r | |
25 | If Seed is NULL, then default seed is used.\r | |
26 | \r | |
27 | @param[in] Seed Pointer to seed value.\r | |
28 | If NULL, default seed is used.\r | |
29 | @param[in] SeedSize Size of seed value.\r | |
30 | If Seed is NULL, this parameter is ignored.\r | |
31 | \r | |
32 | @retval TRUE Pseudorandom number generator has enough entropy for random generation.\r | |
33 | @retval FALSE Pseudorandom number generator does not have enough entropy for random generation.\r | |
34 | \r | |
35 | **/\r | |
36 | BOOLEAN\r | |
37 | EFIAPI\r | |
38 | RandomSeed (\r | |
39 | IN CONST UINT8 *Seed OPTIONAL,\r | |
40 | IN UINTN SeedSize\r | |
41 | )\r | |
42 | {\r | |
43 | CHAR8 DefaultSeed[128];\r | |
44 | \r | |
dda39f3a | 45 | if (SeedSize > INT_MAX) {\r |
46 | return FALSE;\r | |
47 | }\r | |
48 | \r | |
38d91622 LQ |
49 | //\r |
50 | // The software PRNG implementation built in OpenSSL depends on message digest algorithm.\r | |
51 | // Make sure SHA-1 digest algorithm is available here.\r | |
52 | //\r | |
53 | if (EVP_add_digest (EVP_sha1 ()) == 0) {\r | |
54 | return FALSE;\r | |
55 | }\r | |
56 | \r | |
7ce960e7 | 57 | //\r |
58 | // Seed the pseudorandom number generator with user-supplied value.\r | |
59 | // NOTE: A cryptographic PRNG must be seeded with unpredictable data.\r | |
60 | //\r | |
61 | if (Seed != NULL) {\r | |
62 | RAND_seed (Seed, (UINT32) SeedSize);\r | |
63 | } else {\r | |
64 | //\r | |
65 | // Retrieve current time.\r | |
66 | //\r | |
67 | AsciiSPrint (\r | |
68 | DefaultSeed,\r | |
69 | sizeof (DefaultSeed),\r | |
70 | "UEFI Crypto Library default seed (%ld)",\r | |
71 | AsmReadTsc ()\r | |
72 | ); \r | |
73 | \r | |
74 | RAND_seed (DefaultSeed, sizeof (DefaultSeed));\r | |
75 | }\r | |
76 | \r | |
b3a18a1a | 77 | if (RAND_status () == 1) {\r |
78 | return TRUE;\r | |
79 | }\r | |
80 | \r | |
81 | return FALSE;\r | |
7ce960e7 | 82 | }\r |
83 | \r | |
84 | /**\r | |
85 | Generates a pseudorandom byte stream of the specified size.\r | |
86 | \r | |
87 | If Output is NULL, then return FALSE.\r | |
88 | \r | |
89 | @param[out] Output Pointer to buffer to receive random value.\r | |
90 | @param[in] Size Size of randome bytes to generate.\r | |
91 | \r | |
92 | @retval TRUE Pseudorandom byte stream generated successfully.\r | |
93 | @retval FALSE Pseudorandom number generator fails to generate due to lack of entropy.\r | |
94 | \r | |
95 | **/\r | |
96 | BOOLEAN\r | |
97 | EFIAPI\r | |
98 | RandomBytes (\r | |
99 | OUT UINT8 *Output,\r | |
100 | IN UINTN Size\r | |
101 | )\r | |
102 | {\r | |
103 | //\r | |
104 | // Check input parameters.\r | |
105 | //\r | |
dda39f3a | 106 | if (Output == NULL || Size > INT_MAX) {\r |
7ce960e7 | 107 | return FALSE;\r |
108 | }\r | |
109 | \r | |
110 | //\r | |
111 | // Generate random data.\r | |
112 | //\r | |
113 | if (RAND_bytes (Output, (UINT32) Size) != 1) {\r | |
114 | return FALSE;\r | |
115 | }\r | |
116 | \r | |
117 | return TRUE;\r | |
118 | }\r |