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17f0f4a4 NH |
1 | /* |
2 | * RNG: Random Number Generator algorithms under the crypto API | |
3 | * | |
4 | * Copyright (c) 2008 Neil Horman <nhorman@tuxdriver.com> | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify it | |
7 | * under the terms of the GNU General Public License as published by the Free | |
8 | * Software Foundation; either version 2 of the License, or (at your option) | |
9 | * any later version. | |
10 | * | |
11 | */ | |
12 | ||
13 | #ifndef _CRYPTO_RNG_H | |
14 | #define _CRYPTO_RNG_H | |
15 | ||
16 | #include <linux/crypto.h> | |
17 | ||
18 | extern struct crypto_rng *crypto_default_rng; | |
19 | ||
20 | int crypto_get_default_rng(void); | |
21 | void crypto_put_default_rng(void); | |
22 | ||
aa1b6fbc SM |
23 | /** |
24 | * DOC: Random number generator API | |
25 | * | |
26 | * The random number generator API is used with the ciphers of type | |
27 | * CRYPTO_ALG_TYPE_RNG (listed as type "rng" in /proc/crypto) | |
28 | */ | |
29 | ||
17f0f4a4 NH |
30 | static inline struct crypto_rng *__crypto_rng_cast(struct crypto_tfm *tfm) |
31 | { | |
32 | return (struct crypto_rng *)tfm; | |
33 | } | |
34 | ||
aa1b6fbc SM |
35 | /** |
36 | * crypto_alloc_rng() -- allocate RNG handle | |
37 | * @alg_name: is the cra_name / name or cra_driver_name / driver name of the | |
38 | * message digest cipher | |
39 | * @type: specifies the type of the cipher | |
40 | * @mask: specifies the mask for the cipher | |
41 | * | |
42 | * Allocate a cipher handle for a random number generator. The returned struct | |
43 | * crypto_rng is the cipher handle that is required for any subsequent | |
44 | * API invocation for that random number generator. | |
45 | * | |
46 | * For all random number generators, this call creates a new private copy of | |
47 | * the random number generator that does not share a state with other | |
48 | * instances. The only exception is the "krng" random number generator which | |
49 | * is a kernel crypto API use case for the get_random_bytes() function of the | |
50 | * /dev/random driver. | |
51 | * | |
52 | * Return: allocated cipher handle in case of success; IS_ERR() is true in case | |
53 | * of an error, PTR_ERR() returns the error code. | |
54 | */ | |
17f0f4a4 NH |
55 | static inline struct crypto_rng *crypto_alloc_rng(const char *alg_name, |
56 | u32 type, u32 mask) | |
57 | { | |
58 | type &= ~CRYPTO_ALG_TYPE_MASK; | |
59 | type |= CRYPTO_ALG_TYPE_RNG; | |
60 | mask |= CRYPTO_ALG_TYPE_MASK; | |
61 | ||
62 | return __crypto_rng_cast(crypto_alloc_base(alg_name, type, mask)); | |
63 | } | |
64 | ||
65 | static inline struct crypto_tfm *crypto_rng_tfm(struct crypto_rng *tfm) | |
66 | { | |
67 | return &tfm->base; | |
68 | } | |
69 | ||
aa1b6fbc SM |
70 | /** |
71 | * crypto_rng_alg - obtain name of RNG | |
72 | * @tfm: cipher handle | |
73 | * | |
74 | * Return the generic name (cra_name) of the initialized random number generator | |
75 | * | |
76 | * Return: generic name string | |
77 | */ | |
17f0f4a4 NH |
78 | static inline struct rng_alg *crypto_rng_alg(struct crypto_rng *tfm) |
79 | { | |
80 | return &crypto_rng_tfm(tfm)->__crt_alg->cra_rng; | |
81 | } | |
82 | ||
83 | static inline struct rng_tfm *crypto_rng_crt(struct crypto_rng *tfm) | |
84 | { | |
85 | return &crypto_rng_tfm(tfm)->crt_rng; | |
86 | } | |
87 | ||
aa1b6fbc SM |
88 | /** |
89 | * crypto_free_rng() - zeroize and free RNG handle | |
90 | * @tfm: cipher handle to be freed | |
91 | */ | |
17f0f4a4 NH |
92 | static inline void crypto_free_rng(struct crypto_rng *tfm) |
93 | { | |
94 | crypto_free_tfm(crypto_rng_tfm(tfm)); | |
95 | } | |
96 | ||
aa1b6fbc SM |
97 | /** |
98 | * crypto_rng_get_bytes() - get random number | |
99 | * @tfm: cipher handle | |
100 | * @rdata: output buffer holding the random numbers | |
101 | * @dlen: length of the output buffer | |
102 | * | |
103 | * This function fills the caller-allocated buffer with random numbers using the | |
104 | * random number generator referenced by the cipher handle. | |
105 | * | |
cde001e4 | 106 | * Return: 0 function was successful; < 0 if an error occurred |
aa1b6fbc | 107 | */ |
17f0f4a4 NH |
108 | static inline int crypto_rng_get_bytes(struct crypto_rng *tfm, |
109 | u8 *rdata, unsigned int dlen) | |
110 | { | |
111 | return crypto_rng_crt(tfm)->rng_gen_random(tfm, rdata, dlen); | |
112 | } | |
113 | ||
aa1b6fbc SM |
114 | /** |
115 | * crypto_rng_reset() - re-initialize the RNG | |
116 | * @tfm: cipher handle | |
117 | * @seed: seed input data | |
118 | * @slen: length of the seed input data | |
119 | * | |
120 | * The reset function completely re-initializes the random number generator | |
121 | * referenced by the cipher handle by clearing the current state. The new state | |
122 | * is initialized with the caller provided seed or automatically, depending | |
123 | * on the random number generator type (the ANSI X9.31 RNG requires | |
124 | * caller-provided seed, the SP800-90A DRBGs perform an automatic seeding). | |
125 | * The seed is provided as a parameter to this function call. The provided seed | |
126 | * should have the length of the seed size defined for the random number | |
127 | * generator as defined by crypto_rng_seedsize. | |
128 | * | |
129 | * Return: 0 if the setting of the key was successful; < 0 if an error occurred | |
130 | */ | |
17f0f4a4 NH |
131 | static inline int crypto_rng_reset(struct crypto_rng *tfm, |
132 | u8 *seed, unsigned int slen) | |
133 | { | |
134 | return crypto_rng_crt(tfm)->rng_reset(tfm, seed, slen); | |
135 | } | |
136 | ||
aa1b6fbc SM |
137 | /** |
138 | * crypto_rng_seedsize() - obtain seed size of RNG | |
139 | * @tfm: cipher handle | |
140 | * | |
141 | * The function returns the seed size for the random number generator | |
142 | * referenced by the cipher handle. This value may be zero if the random | |
143 | * number generator does not implement or require a reseeding. For example, | |
144 | * the SP800-90A DRBGs implement an automated reseeding after reaching a | |
145 | * pre-defined threshold. | |
146 | * | |
147 | * Return: seed size for the random number generator | |
148 | */ | |
17f0f4a4 NH |
149 | static inline int crypto_rng_seedsize(struct crypto_rng *tfm) |
150 | { | |
151 | return crypto_rng_alg(tfm)->seedsize; | |
152 | } | |
153 | ||
154 | #endif |