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2874c5fd | 1 | /* SPDX-License-Identifier: GPL-2.0-or-later */ |
17f0f4a4 NH |
2 | /* |
3 | * RNG: Random Number Generator algorithms under the crypto API | |
4 | * | |
5 | * Copyright (c) 2008 Neil Horman <nhorman@tuxdriver.com> | |
94f1bb15 | 6 | * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au> |
17f0f4a4 NH |
7 | */ |
8 | ||
9 | #ifndef _CRYPTO_RNG_H | |
10 | #define _CRYPTO_RNG_H | |
11 | ||
9807e49b HX |
12 | #include <linux/atomic.h> |
13 | #include <linux/container_of.h> | |
17f0f4a4 NH |
14 | #include <linux/crypto.h> |
15 | ||
acec27ff HX |
16 | struct crypto_rng; |
17 | ||
18 | /** | |
19 | * struct rng_alg - random number generator definition | |
20 | * | |
21 | * @generate: The function defined by this variable obtains a | |
22 | * random number. The random number generator transform | |
23 | * must generate the random number out of the context | |
24 | * provided with this call, plus any additional data | |
25 | * if provided to the call. | |
26 | * @seed: Seed or reseed the random number generator. With the | |
27 | * invocation of this function call, the random number | |
12f7c14a | 28 | * generator shall become ready for generation. If the |
acec27ff HX |
29 | * random number generator requires a seed for setting |
30 | * up a new state, the seed must be provided by the | |
31 | * consumer while invoking this function. The required | |
32 | * size of the seed is defined with @seedsize . | |
7ca99d81 HX |
33 | * @set_ent: Set entropy that would otherwise be obtained from |
34 | * entropy source. Internal use only. | |
acec27ff HX |
35 | * @seedsize: The seed size required for a random number generator |
36 | * initialization defined with this variable. Some | |
37 | * random number generators does not require a seed | |
38 | * as the seeding is implemented internally without | |
39 | * the need of support by the consumer. In this case, | |
40 | * the seed size is set to zero. | |
41 | * @base: Common crypto API algorithm data structure. | |
42 | */ | |
43 | struct rng_alg { | |
44 | int (*generate)(struct crypto_rng *tfm, | |
45 | const u8 *src, unsigned int slen, | |
46 | u8 *dst, unsigned int dlen); | |
47 | int (*seed)(struct crypto_rng *tfm, const u8 *seed, unsigned int slen); | |
7ca99d81 HX |
48 | void (*set_ent)(struct crypto_rng *tfm, const u8 *data, |
49 | unsigned int len); | |
acec27ff HX |
50 | |
51 | unsigned int seedsize; | |
52 | ||
53 | struct crypto_alg base; | |
54 | }; | |
55 | ||
d0e83059 | 56 | struct crypto_rng { |
d0e83059 HX |
57 | struct crypto_tfm base; |
58 | }; | |
59 | ||
17f0f4a4 NH |
60 | extern struct crypto_rng *crypto_default_rng; |
61 | ||
62 | int crypto_get_default_rng(void); | |
63 | void crypto_put_default_rng(void); | |
64 | ||
aa1b6fbc SM |
65 | /** |
66 | * DOC: Random number generator API | |
67 | * | |
68 | * The random number generator API is used with the ciphers of type | |
69 | * CRYPTO_ALG_TYPE_RNG (listed as type "rng" in /proc/crypto) | |
70 | */ | |
71 | ||
aa1b6fbc SM |
72 | /** |
73 | * crypto_alloc_rng() -- allocate RNG handle | |
74 | * @alg_name: is the cra_name / name or cra_driver_name / driver name of the | |
75 | * message digest cipher | |
76 | * @type: specifies the type of the cipher | |
77 | * @mask: specifies the mask for the cipher | |
78 | * | |
79 | * Allocate a cipher handle for a random number generator. The returned struct | |
80 | * crypto_rng is the cipher handle that is required for any subsequent | |
81 | * API invocation for that random number generator. | |
82 | * | |
83 | * For all random number generators, this call creates a new private copy of | |
84 | * the random number generator that does not share a state with other | |
85 | * instances. The only exception is the "krng" random number generator which | |
86 | * is a kernel crypto API use case for the get_random_bytes() function of the | |
87 | * /dev/random driver. | |
88 | * | |
89 | * Return: allocated cipher handle in case of success; IS_ERR() is true in case | |
90 | * of an error, PTR_ERR() returns the error code. | |
91 | */ | |
d0e83059 | 92 | struct crypto_rng *crypto_alloc_rng(const char *alg_name, u32 type, u32 mask); |
17f0f4a4 NH |
93 | |
94 | static inline struct crypto_tfm *crypto_rng_tfm(struct crypto_rng *tfm) | |
95 | { | |
96 | return &tfm->base; | |
97 | } | |
98 | ||
9807e49b HX |
99 | static inline struct rng_alg *__crypto_rng_alg(struct crypto_alg *alg) |
100 | { | |
101 | return container_of(alg, struct rng_alg, base); | |
102 | } | |
103 | ||
aa1b6fbc SM |
104 | /** |
105 | * crypto_rng_alg - obtain name of RNG | |
106 | * @tfm: cipher handle | |
107 | * | |
108 | * Return the generic name (cra_name) of the initialized random number generator | |
109 | * | |
110 | * Return: generic name string | |
111 | */ | |
17f0f4a4 NH |
112 | static inline struct rng_alg *crypto_rng_alg(struct crypto_rng *tfm) |
113 | { | |
9807e49b | 114 | return __crypto_rng_alg(crypto_rng_tfm(tfm)->__crt_alg); |
17f0f4a4 NH |
115 | } |
116 | ||
aa1b6fbc SM |
117 | /** |
118 | * crypto_free_rng() - zeroize and free RNG handle | |
119 | * @tfm: cipher handle to be freed | |
83681f2b AB |
120 | * |
121 | * If @tfm is a NULL or error pointer, this function does nothing. | |
aa1b6fbc | 122 | */ |
17f0f4a4 NH |
123 | static inline void crypto_free_rng(struct crypto_rng *tfm) |
124 | { | |
d0e83059 | 125 | crypto_destroy_tfm(tfm, crypto_rng_tfm(tfm)); |
17f0f4a4 NH |
126 | } |
127 | ||
ff030b09 HX |
128 | /** |
129 | * crypto_rng_generate() - get random number | |
130 | * @tfm: cipher handle | |
131 | * @src: Input buffer holding additional data, may be NULL | |
132 | * @slen: Length of additional data | |
133 | * @dst: output buffer holding the random numbers | |
134 | * @dlen: length of the output buffer | |
135 | * | |
136 | * This function fills the caller-allocated buffer with random | |
137 | * numbers using the random number generator referenced by the | |
138 | * cipher handle. | |
139 | * | |
140 | * Return: 0 function was successful; < 0 if an error occurred | |
141 | */ | |
142 | static inline int crypto_rng_generate(struct crypto_rng *tfm, | |
143 | const u8 *src, unsigned int slen, | |
144 | u8 *dst, unsigned int dlen) | |
145 | { | |
2beb81fb | 146 | return crypto_rng_alg(tfm)->generate(tfm, src, slen, dst, dlen); |
ff030b09 HX |
147 | } |
148 | ||
aa1b6fbc SM |
149 | /** |
150 | * crypto_rng_get_bytes() - get random number | |
151 | * @tfm: cipher handle | |
152 | * @rdata: output buffer holding the random numbers | |
153 | * @dlen: length of the output buffer | |
154 | * | |
155 | * This function fills the caller-allocated buffer with random numbers using the | |
156 | * random number generator referenced by the cipher handle. | |
157 | * | |
cde001e4 | 158 | * Return: 0 function was successful; < 0 if an error occurred |
aa1b6fbc | 159 | */ |
17f0f4a4 NH |
160 | static inline int crypto_rng_get_bytes(struct crypto_rng *tfm, |
161 | u8 *rdata, unsigned int dlen) | |
162 | { | |
ff030b09 | 163 | return crypto_rng_generate(tfm, NULL, 0, rdata, dlen); |
17f0f4a4 NH |
164 | } |
165 | ||
aa1b6fbc SM |
166 | /** |
167 | * crypto_rng_reset() - re-initialize the RNG | |
168 | * @tfm: cipher handle | |
169 | * @seed: seed input data | |
170 | * @slen: length of the seed input data | |
171 | * | |
172 | * The reset function completely re-initializes the random number generator | |
173 | * referenced by the cipher handle by clearing the current state. The new state | |
174 | * is initialized with the caller provided seed or automatically, depending | |
175 | * on the random number generator type (the ANSI X9.31 RNG requires | |
176 | * caller-provided seed, the SP800-90A DRBGs perform an automatic seeding). | |
177 | * The seed is provided as a parameter to this function call. The provided seed | |
178 | * should have the length of the seed size defined for the random number | |
179 | * generator as defined by crypto_rng_seedsize. | |
180 | * | |
181 | * Return: 0 if the setting of the key was successful; < 0 if an error occurred | |
182 | */ | |
3c5d8fa9 HX |
183 | int crypto_rng_reset(struct crypto_rng *tfm, const u8 *seed, |
184 | unsigned int slen); | |
17f0f4a4 | 185 | |
aa1b6fbc SM |
186 | /** |
187 | * crypto_rng_seedsize() - obtain seed size of RNG | |
188 | * @tfm: cipher handle | |
189 | * | |
190 | * The function returns the seed size for the random number generator | |
191 | * referenced by the cipher handle. This value may be zero if the random | |
192 | * number generator does not implement or require a reseeding. For example, | |
193 | * the SP800-90A DRBGs implement an automated reseeding after reaching a | |
194 | * pre-defined threshold. | |
195 | * | |
196 | * Return: seed size for the random number generator | |
197 | */ | |
17f0f4a4 NH |
198 | static inline int crypto_rng_seedsize(struct crypto_rng *tfm) |
199 | { | |
94f1bb15 | 200 | return crypto_rng_alg(tfm)->seedsize; |
17f0f4a4 NH |
201 | } |
202 | ||
203 | #endif |