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7ce960e7 1/** @file\r
2 Pseudorandom Number Generator Wrapper Implementation over OpenSSL.\r
3\r
630f67dd 4Copyright (c) 2012 - 2018, Intel Corporation. All rights reserved.<BR>\r
2009f6b4 5SPDX-License-Identifier: BSD-2-Clause-Patent\r
7ce960e7 6\r
7**/\r
8\r
9#include "InternalCryptLib.h"\r
10#include <openssl/rand.h>\r
38d91622 11#include <openssl/evp.h>\r
7ce960e7 12#include <Library/PrintLib.h>\r
13\r
14/**\r
15 Sets up the seed value for the pseudorandom number generator.\r
16\r
17 This function sets up the seed value for the pseudorandom number generator.\r
18 If Seed is not NULL, then the seed passed in is used.\r
19 If Seed is NULL, then default seed is used.\r
20\r
21 @param[in] Seed Pointer to seed value.\r
22 If NULL, default seed is used.\r
23 @param[in] SeedSize Size of seed value.\r
24 If Seed is NULL, this parameter is ignored.\r
25\r
26 @retval TRUE Pseudorandom number generator has enough entropy for random generation.\r
27 @retval FALSE Pseudorandom number generator does not have enough entropy for random generation.\r
28\r
29**/\r
30BOOLEAN\r
31EFIAPI\r
32RandomSeed (\r
33 IN CONST UINT8 *Seed OPTIONAL,\r
34 IN UINTN SeedSize\r
35 )\r
36{\r
37 CHAR8 DefaultSeed[128];\r
38\r
dda39f3a 39 if (SeedSize > INT_MAX) {\r
40 return FALSE;\r
41 }\r
42\r
38d91622
LQ
43 //\r
44 // The software PRNG implementation built in OpenSSL depends on message digest algorithm.\r
45 // Make sure SHA-1 digest algorithm is available here.\r
46 //\r
47 if (EVP_add_digest (EVP_sha1 ()) == 0) {\r
48 return FALSE;\r
49 }\r
50\r
7ce960e7 51 //\r
52 // Seed the pseudorandom number generator with user-supplied value.\r
53 // NOTE: A cryptographic PRNG must be seeded with unpredictable data.\r
54 //\r
55 if (Seed != NULL) {\r
7c342378 56 RAND_seed (Seed, (UINT32)SeedSize);\r
7ce960e7 57 } else {\r
58 //\r
59 // Retrieve current time.\r
60 //\r
61 AsciiSPrint (\r
62 DefaultSeed,\r
63 sizeof (DefaultSeed),\r
64 "UEFI Crypto Library default seed (%ld)",\r
65 AsmReadTsc ()\r
630f67dd 66 );\r
7ce960e7 67\r
68 RAND_seed (DefaultSeed, sizeof (DefaultSeed));\r
69 }\r
70\r
b3a18a1a 71 if (RAND_status () == 1) {\r
72 return TRUE;\r
73 }\r
74\r
75 return FALSE;\r
7ce960e7 76}\r
77\r
78/**\r
79 Generates a pseudorandom byte stream of the specified size.\r
80\r
81 If Output is NULL, then return FALSE.\r
82\r
83 @param[out] Output Pointer to buffer to receive random value.\r
2998af86 84 @param[in] Size Size of random bytes to generate.\r
7ce960e7 85\r
86 @retval TRUE Pseudorandom byte stream generated successfully.\r
87 @retval FALSE Pseudorandom number generator fails to generate due to lack of entropy.\r
88\r
89**/\r
90BOOLEAN\r
91EFIAPI\r
92RandomBytes (\r
93 OUT UINT8 *Output,\r
94 IN UINTN Size\r
95 )\r
96{\r
97 //\r
98 // Check input parameters.\r
99 //\r
7c342378 100 if ((Output == NULL) || (Size > INT_MAX)) {\r
7ce960e7 101 return FALSE;\r
102 }\r
103\r
104 //\r
105 // Generate random data.\r
106 //\r
7c342378 107 if (RAND_bytes (Output, (UINT32)Size) != 1) {\r
7ce960e7 108 return FALSE;\r
109 }\r
110\r
111 return TRUE;\r
112}\r