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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/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * RNG: Random Number Generator algorithms under the crypto API
4 *
5 * Copyright (c) 2008 Neil Horman <nhorman@tuxdriver.com>
6 * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
7 */
8
9#ifndef _CRYPTO_RNG_H
10#define _CRYPTO_RNG_H
11
12#include <linux/atomic.h>
13#include <linux/container_of.h>
14#include <linux/crypto.h>
15
16struct crypto_rng;
17
18/*
19 * struct crypto_istat_rng: statistics for RNG algorithm
20 * @generate_cnt: number of RNG generate requests
21 * @generate_tlen: total data size of generated data by the RNG
22 * @seed_cnt: number of times the RNG was seeded
23 * @err_cnt: number of error for RNG requests
24 */
25struct crypto_istat_rng {
26 atomic64_t generate_cnt;
27 atomic64_t generate_tlen;
28 atomic64_t seed_cnt;
29 atomic64_t err_cnt;
30};
31
32/**
33 * struct rng_alg - random number generator definition
34 *
35 * @generate: The function defined by this variable obtains a
36 * random number. The random number generator transform
37 * must generate the random number out of the context
38 * provided with this call, plus any additional data
39 * if provided to the call.
40 * @seed: Seed or reseed the random number generator. With the
41 * invocation of this function call, the random number
42 * generator shall become ready for generation. If the
43 * random number generator requires a seed for setting
44 * up a new state, the seed must be provided by the
45 * consumer while invoking this function. The required
46 * size of the seed is defined with @seedsize .
47 * @set_ent: Set entropy that would otherwise be obtained from
48 * entropy source. Internal use only.
49 * @stat: Statistics for rng algorithm
50 * @seedsize: The seed size required for a random number generator
51 * initialization defined with this variable. Some
52 * random number generators does not require a seed
53 * as the seeding is implemented internally without
54 * the need of support by the consumer. In this case,
55 * the seed size is set to zero.
56 * @base: Common crypto API algorithm data structure.
57 */
58struct rng_alg {
59 int (*generate)(struct crypto_rng *tfm,
60 const u8 *src, unsigned int slen,
61 u8 *dst, unsigned int dlen);
62 int (*seed)(struct crypto_rng *tfm, const u8 *seed, unsigned int slen);
63 void (*set_ent)(struct crypto_rng *tfm, const u8 *data,
64 unsigned int len);
65
66#ifdef CONFIG_CRYPTO_STATS
67 struct crypto_istat_rng stat;
68#endif
69
70 unsigned int seedsize;
71
72 struct crypto_alg base;
73};
74
75struct crypto_rng {
76 struct crypto_tfm base;
77};
78
79extern struct crypto_rng *crypto_default_rng;
80
81int crypto_get_default_rng(void);
82void crypto_put_default_rng(void);
83
84/**
85 * DOC: Random number generator API
86 *
87 * The random number generator API is used with the ciphers of type
88 * CRYPTO_ALG_TYPE_RNG (listed as type "rng" in /proc/crypto)
89 */
90
91/**
92 * crypto_alloc_rng() -- allocate RNG handle
93 * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
94 * message digest cipher
95 * @type: specifies the type of the cipher
96 * @mask: specifies the mask for the cipher
97 *
98 * Allocate a cipher handle for a random number generator. The returned struct
99 * crypto_rng is the cipher handle that is required for any subsequent
100 * API invocation for that random number generator.
101 *
102 * For all random number generators, this call creates a new private copy of
103 * the random number generator that does not share a state with other
104 * instances. The only exception is the "krng" random number generator which
105 * is a kernel crypto API use case for the get_random_bytes() function of the
106 * /dev/random driver.
107 *
108 * Return: allocated cipher handle in case of success; IS_ERR() is true in case
109 * of an error, PTR_ERR() returns the error code.
110 */
111struct crypto_rng *crypto_alloc_rng(const char *alg_name, u32 type, u32 mask);
112
113static inline struct crypto_tfm *crypto_rng_tfm(struct crypto_rng *tfm)
114{
115 return &tfm->base;
116}
117
118static inline struct rng_alg *__crypto_rng_alg(struct crypto_alg *alg)
119{
120 return container_of(alg, struct rng_alg, base);
121}
122
123/**
124 * crypto_rng_alg - obtain name of RNG
125 * @tfm: cipher handle
126 *
127 * Return the generic name (cra_name) of the initialized random number generator
128 *
129 * Return: generic name string
130 */
131static inline struct rng_alg *crypto_rng_alg(struct crypto_rng *tfm)
132{
133 return __crypto_rng_alg(crypto_rng_tfm(tfm)->__crt_alg);
134}
135
136/**
137 * crypto_free_rng() - zeroize and free RNG handle
138 * @tfm: cipher handle to be freed
139 *
140 * If @tfm is a NULL or error pointer, this function does nothing.
141 */
142static inline void crypto_free_rng(struct crypto_rng *tfm)
143{
144 crypto_destroy_tfm(tfm, crypto_rng_tfm(tfm));
145}
146
147static inline struct crypto_istat_rng *rng_get_stat(struct rng_alg *alg)
148{
149#ifdef CONFIG_CRYPTO_STATS
150 return &alg->stat;
151#else
152 return NULL;
153#endif
154}
155
156static inline int crypto_rng_errstat(struct rng_alg *alg, int err)
157{
158 if (!IS_ENABLED(CONFIG_CRYPTO_STATS))
159 return err;
160
161 if (err && err != -EINPROGRESS && err != -EBUSY)
162 atomic64_inc(&rng_get_stat(alg)->err_cnt);
163
164 return err;
165}
166
167/**
168 * crypto_rng_generate() - get random number
169 * @tfm: cipher handle
170 * @src: Input buffer holding additional data, may be NULL
171 * @slen: Length of additional data
172 * @dst: output buffer holding the random numbers
173 * @dlen: length of the output buffer
174 *
175 * This function fills the caller-allocated buffer with random
176 * numbers using the random number generator referenced by the
177 * cipher handle.
178 *
179 * Return: 0 function was successful; < 0 if an error occurred
180 */
181static inline int crypto_rng_generate(struct crypto_rng *tfm,
182 const u8 *src, unsigned int slen,
183 u8 *dst, unsigned int dlen)
184{
185 struct rng_alg *alg = crypto_rng_alg(tfm);
186
187 if (IS_ENABLED(CONFIG_CRYPTO_STATS)) {
188 struct crypto_istat_rng *istat = rng_get_stat(alg);
189
190 atomic64_inc(&istat->generate_cnt);
191 atomic64_add(dlen, &istat->generate_tlen);
192 }
193
194 return crypto_rng_errstat(alg,
195 alg->generate(tfm, src, slen, dst, dlen));
196}
197
198/**
199 * crypto_rng_get_bytes() - get random number
200 * @tfm: cipher handle
201 * @rdata: output buffer holding the random numbers
202 * @dlen: length of the output buffer
203 *
204 * This function fills the caller-allocated buffer with random numbers using the
205 * random number generator referenced by the cipher handle.
206 *
207 * Return: 0 function was successful; < 0 if an error occurred
208 */
209static inline int crypto_rng_get_bytes(struct crypto_rng *tfm,
210 u8 *rdata, unsigned int dlen)
211{
212 return crypto_rng_generate(tfm, NULL, 0, rdata, dlen);
213}
214
215/**
216 * crypto_rng_reset() - re-initialize the RNG
217 * @tfm: cipher handle
218 * @seed: seed input data
219 * @slen: length of the seed input data
220 *
221 * The reset function completely re-initializes the random number generator
222 * referenced by the cipher handle by clearing the current state. The new state
223 * is initialized with the caller provided seed or automatically, depending
224 * on the random number generator type (the ANSI X9.31 RNG requires
225 * caller-provided seed, the SP800-90A DRBGs perform an automatic seeding).
226 * The seed is provided as a parameter to this function call. The provided seed
227 * should have the length of the seed size defined for the random number
228 * generator as defined by crypto_rng_seedsize.
229 *
230 * Return: 0 if the setting of the key was successful; < 0 if an error occurred
231 */
232int crypto_rng_reset(struct crypto_rng *tfm, const u8 *seed,
233 unsigned int slen);
234
235/**
236 * crypto_rng_seedsize() - obtain seed size of RNG
237 * @tfm: cipher handle
238 *
239 * The function returns the seed size for the random number generator
240 * referenced by the cipher handle. This value may be zero if the random
241 * number generator does not implement or require a reseeding. For example,
242 * the SP800-90A DRBGs implement an automated reseeding after reaching a
243 * pre-defined threshold.
244 *
245 * Return: seed size for the random number generator
246 */
247static inline int crypto_rng_seedsize(struct crypto_rng *tfm)
248{
249 return crypto_rng_alg(tfm)->seedsize;
250}
251
252#endif