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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
18extern struct crypto_rng *crypto_default_rng;
19
20int crypto_get_default_rng(void);
21void crypto_put_default_rng(void);
22
23static inline struct crypto_rng *__crypto_rng_cast(struct crypto_tfm *tfm)
24{
25 return (struct crypto_rng *)tfm;
26}
27
28static inline struct crypto_rng *crypto_alloc_rng(const char *alg_name,
29 u32 type, u32 mask)
30{
31 type &= ~CRYPTO_ALG_TYPE_MASK;
32 type |= CRYPTO_ALG_TYPE_RNG;
33 mask |= CRYPTO_ALG_TYPE_MASK;
34
35 return __crypto_rng_cast(crypto_alloc_base(alg_name, type, mask));
36}
37
38static inline struct crypto_tfm *crypto_rng_tfm(struct crypto_rng *tfm)
39{
40 return &tfm->base;
41}
42
43static inline struct rng_alg *crypto_rng_alg(struct crypto_rng *tfm)
44{
45 return &crypto_rng_tfm(tfm)->__crt_alg->cra_rng;
46}
47
48static inline struct rng_tfm *crypto_rng_crt(struct crypto_rng *tfm)
49{
50 return &crypto_rng_tfm(tfm)->crt_rng;
51}
52
53static inline void crypto_free_rng(struct crypto_rng *tfm)
54{
55 crypto_free_tfm(crypto_rng_tfm(tfm));
56}
57
58static inline int crypto_rng_get_bytes(struct crypto_rng *tfm,
59 u8 *rdata, unsigned int dlen)
60{
61 return crypto_rng_crt(tfm)->rng_gen_random(tfm, rdata, dlen);
62}
63
64static inline int crypto_rng_reset(struct crypto_rng *tfm,
65 u8 *seed, unsigned int slen)
66{
67 return crypto_rng_crt(tfm)->rng_reset(tfm, seed, slen);
68}
69
70static inline int crypto_rng_seedsize(struct crypto_rng *tfm)
71{
72 return crypto_rng_alg(tfm)->seedsize;
73}
74
75#endif
1/*
2 * RNG: Random Number Generator algorithms under the crypto API
3 *
4 * Copyright (c) 2008 Neil Horman <nhorman@tuxdriver.com>
5 * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License as published by the Free
9 * Software Foundation; either version 2 of the License, or (at your option)
10 * any later version.
11 *
12 */
13
14#ifndef _CRYPTO_RNG_H
15#define _CRYPTO_RNG_H
16
17#include <linux/crypto.h>
18
19struct crypto_rng;
20
21/**
22 * struct rng_alg - random number generator definition
23 *
24 * @generate: The function defined by this variable obtains a
25 * random number. The random number generator transform
26 * must generate the random number out of the context
27 * provided with this call, plus any additional data
28 * if provided to the call.
29 * @seed: Seed or reseed the random number generator. With the
30 * invocation of this function call, the random number
31 * generator shall become ready for generation. If the
32 * random number generator requires a seed for setting
33 * up a new state, the seed must be provided by the
34 * consumer while invoking this function. The required
35 * size of the seed is defined with @seedsize .
36 * @set_ent: Set entropy that would otherwise be obtained from
37 * entropy source. Internal use only.
38 * @seedsize: The seed size required for a random number generator
39 * initialization defined with this variable. Some
40 * random number generators does not require a seed
41 * as the seeding is implemented internally without
42 * the need of support by the consumer. In this case,
43 * the seed size is set to zero.
44 * @base: Common crypto API algorithm data structure.
45 */
46struct rng_alg {
47 int (*generate)(struct crypto_rng *tfm,
48 const u8 *src, unsigned int slen,
49 u8 *dst, unsigned int dlen);
50 int (*seed)(struct crypto_rng *tfm, const u8 *seed, unsigned int slen);
51 void (*set_ent)(struct crypto_rng *tfm, const u8 *data,
52 unsigned int len);
53
54 unsigned int seedsize;
55
56 struct crypto_alg base;
57};
58
59struct crypto_rng {
60 struct crypto_tfm base;
61};
62
63extern struct crypto_rng *crypto_default_rng;
64
65int crypto_get_default_rng(void);
66void crypto_put_default_rng(void);
67
68/**
69 * DOC: Random number generator API
70 *
71 * The random number generator API is used with the ciphers of type
72 * CRYPTO_ALG_TYPE_RNG (listed as type "rng" in /proc/crypto)
73 */
74
75/**
76 * crypto_alloc_rng() -- allocate RNG handle
77 * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
78 * message digest cipher
79 * @type: specifies the type of the cipher
80 * @mask: specifies the mask for the cipher
81 *
82 * Allocate a cipher handle for a random number generator. The returned struct
83 * crypto_rng is the cipher handle that is required for any subsequent
84 * API invocation for that random number generator.
85 *
86 * For all random number generators, this call creates a new private copy of
87 * the random number generator that does not share a state with other
88 * instances. The only exception is the "krng" random number generator which
89 * is a kernel crypto API use case for the get_random_bytes() function of the
90 * /dev/random driver.
91 *
92 * Return: allocated cipher handle in case of success; IS_ERR() is true in case
93 * of an error, PTR_ERR() returns the error code.
94 */
95struct crypto_rng *crypto_alloc_rng(const char *alg_name, u32 type, u32 mask);
96
97static inline struct crypto_tfm *crypto_rng_tfm(struct crypto_rng *tfm)
98{
99 return &tfm->base;
100}
101
102/**
103 * crypto_rng_alg - obtain name of RNG
104 * @tfm: cipher handle
105 *
106 * Return the generic name (cra_name) of the initialized random number generator
107 *
108 * Return: generic name string
109 */
110static inline struct rng_alg *crypto_rng_alg(struct crypto_rng *tfm)
111{
112 return container_of(crypto_rng_tfm(tfm)->__crt_alg,
113 struct rng_alg, base);
114}
115
116/**
117 * crypto_free_rng() - zeroize and free RNG handle
118 * @tfm: cipher handle to be freed
119 */
120static inline void crypto_free_rng(struct crypto_rng *tfm)
121{
122 crypto_destroy_tfm(tfm, crypto_rng_tfm(tfm));
123}
124
125/**
126 * crypto_rng_generate() - get random number
127 * @tfm: cipher handle
128 * @src: Input buffer holding additional data, may be NULL
129 * @slen: Length of additional data
130 * @dst: output buffer holding the random numbers
131 * @dlen: length of the output buffer
132 *
133 * This function fills the caller-allocated buffer with random
134 * numbers using the random number generator referenced by the
135 * cipher handle.
136 *
137 * Return: 0 function was successful; < 0 if an error occurred
138 */
139static inline int crypto_rng_generate(struct crypto_rng *tfm,
140 const u8 *src, unsigned int slen,
141 u8 *dst, unsigned int dlen)
142{
143 return crypto_rng_alg(tfm)->generate(tfm, src, slen, dst, dlen);
144}
145
146/**
147 * crypto_rng_get_bytes() - get random number
148 * @tfm: cipher handle
149 * @rdata: output buffer holding the random numbers
150 * @dlen: length of the output buffer
151 *
152 * This function fills the caller-allocated buffer with random numbers using the
153 * random number generator referenced by the cipher handle.
154 *
155 * Return: 0 function was successful; < 0 if an error occurred
156 */
157static inline int crypto_rng_get_bytes(struct crypto_rng *tfm,
158 u8 *rdata, unsigned int dlen)
159{
160 return crypto_rng_generate(tfm, NULL, 0, rdata, dlen);
161}
162
163/**
164 * crypto_rng_reset() - re-initialize the RNG
165 * @tfm: cipher handle
166 * @seed: seed input data
167 * @slen: length of the seed input data
168 *
169 * The reset function completely re-initializes the random number generator
170 * referenced by the cipher handle by clearing the current state. The new state
171 * is initialized with the caller provided seed or automatically, depending
172 * on the random number generator type (the ANSI X9.31 RNG requires
173 * caller-provided seed, the SP800-90A DRBGs perform an automatic seeding).
174 * The seed is provided as a parameter to this function call. The provided seed
175 * should have the length of the seed size defined for the random number
176 * generator as defined by crypto_rng_seedsize.
177 *
178 * Return: 0 if the setting of the key was successful; < 0 if an error occurred
179 */
180int crypto_rng_reset(struct crypto_rng *tfm, const u8 *seed,
181 unsigned int slen);
182
183/**
184 * crypto_rng_seedsize() - obtain seed size of RNG
185 * @tfm: cipher handle
186 *
187 * The function returns the seed size for the random number generator
188 * referenced by the cipher handle. This value may be zero if the random
189 * number generator does not implement or require a reseeding. For example,
190 * the SP800-90A DRBGs implement an automated reseeding after reaching a
191 * pre-defined threshold.
192 *
193 * Return: seed size for the random number generator
194 */
195static inline int crypto_rng_seedsize(struct crypto_rng *tfm)
196{
197 return crypto_rng_alg(tfm)->seedsize;
198}
199
200#endif