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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> | |
94f1bb15 | 5 | * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au> |
17f0f4a4 NH |
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 | ||
acec27ff HX |
19 | struct 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 | |
12f7c14a | 31 | * generator shall become ready for generation. If the |
acec27ff HX |
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 . | |
7ca99d81 HX |
36 | * @set_ent: Set entropy that would otherwise be obtained from |
37 | * entropy source. Internal use only. | |
acec27ff HX |
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 | */ | |
46 | struct 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); | |
7ca99d81 HX |
51 | void (*set_ent)(struct crypto_rng *tfm, const u8 *data, |
52 | unsigned int len); | |
acec27ff HX |
53 | |
54 | unsigned int seedsize; | |
55 | ||
56 | struct crypto_alg base; | |
57 | }; | |
58 | ||
d0e83059 | 59 | struct crypto_rng { |
d0e83059 HX |
60 | struct crypto_tfm base; |
61 | }; | |
62 | ||
17f0f4a4 NH |
63 | extern struct crypto_rng *crypto_default_rng; |
64 | ||
65 | int crypto_get_default_rng(void); | |
66 | void crypto_put_default_rng(void); | |
67 | ||
aa1b6fbc SM |
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 | ||
aa1b6fbc SM |
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 | */ | |
d0e83059 | 95 | struct crypto_rng *crypto_alloc_rng(const char *alg_name, u32 type, u32 mask); |
17f0f4a4 NH |
96 | |
97 | static inline struct crypto_tfm *crypto_rng_tfm(struct crypto_rng *tfm) | |
98 | { | |
99 | return &tfm->base; | |
100 | } | |
101 | ||
aa1b6fbc SM |
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 | */ | |
17f0f4a4 NH |
110 | static inline struct rng_alg *crypto_rng_alg(struct crypto_rng *tfm) |
111 | { | |
acec27ff HX |
112 | return container_of(crypto_rng_tfm(tfm)->__crt_alg, |
113 | struct rng_alg, base); | |
17f0f4a4 NH |
114 | } |
115 | ||
aa1b6fbc SM |
116 | /** |
117 | * crypto_free_rng() - zeroize and free RNG handle | |
118 | * @tfm: cipher handle to be freed | |
119 | */ | |
17f0f4a4 NH |
120 | static inline void crypto_free_rng(struct crypto_rng *tfm) |
121 | { | |
d0e83059 | 122 | crypto_destroy_tfm(tfm, crypto_rng_tfm(tfm)); |
17f0f4a4 NH |
123 | } |
124 | ||
ff030b09 HX |
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 | */ | |
139 | static inline int crypto_rng_generate(struct crypto_rng *tfm, | |
140 | const u8 *src, unsigned int slen, | |
141 | u8 *dst, unsigned int dlen) | |
142 | { | |
f7d76e05 | 143 | struct crypto_alg *alg = tfm->base.__crt_alg; |
cac5818c CL |
144 | int ret; |
145 | ||
f7d76e05 | 146 | crypto_stats_get(alg); |
cac5818c | 147 | ret = crypto_rng_alg(tfm)->generate(tfm, src, slen, dst, dlen); |
f7d76e05 | 148 | crypto_stats_rng_generate(alg, dlen, ret); |
cac5818c | 149 | return ret; |
ff030b09 HX |
150 | } |
151 | ||
aa1b6fbc SM |
152 | /** |
153 | * crypto_rng_get_bytes() - get random number | |
154 | * @tfm: cipher handle | |
155 | * @rdata: output buffer holding the random numbers | |
156 | * @dlen: length of the output buffer | |
157 | * | |
158 | * This function fills the caller-allocated buffer with random numbers using the | |
159 | * random number generator referenced by the cipher handle. | |
160 | * | |
cde001e4 | 161 | * Return: 0 function was successful; < 0 if an error occurred |
aa1b6fbc | 162 | */ |
17f0f4a4 NH |
163 | static inline int crypto_rng_get_bytes(struct crypto_rng *tfm, |
164 | u8 *rdata, unsigned int dlen) | |
165 | { | |
ff030b09 | 166 | return crypto_rng_generate(tfm, NULL, 0, rdata, dlen); |
17f0f4a4 NH |
167 | } |
168 | ||
aa1b6fbc SM |
169 | /** |
170 | * crypto_rng_reset() - re-initialize the RNG | |
171 | * @tfm: cipher handle | |
172 | * @seed: seed input data | |
173 | * @slen: length of the seed input data | |
174 | * | |
175 | * The reset function completely re-initializes the random number generator | |
176 | * referenced by the cipher handle by clearing the current state. The new state | |
177 | * is initialized with the caller provided seed or automatically, depending | |
178 | * on the random number generator type (the ANSI X9.31 RNG requires | |
179 | * caller-provided seed, the SP800-90A DRBGs perform an automatic seeding). | |
180 | * The seed is provided as a parameter to this function call. The provided seed | |
181 | * should have the length of the seed size defined for the random number | |
182 | * generator as defined by crypto_rng_seedsize. | |
183 | * | |
184 | * Return: 0 if the setting of the key was successful; < 0 if an error occurred | |
185 | */ | |
3c5d8fa9 HX |
186 | int crypto_rng_reset(struct crypto_rng *tfm, const u8 *seed, |
187 | unsigned int slen); | |
17f0f4a4 | 188 | |
aa1b6fbc SM |
189 | /** |
190 | * crypto_rng_seedsize() - obtain seed size of RNG | |
191 | * @tfm: cipher handle | |
192 | * | |
193 | * The function returns the seed size for the random number generator | |
194 | * referenced by the cipher handle. This value may be zero if the random | |
195 | * number generator does not implement or require a reseeding. For example, | |
196 | * the SP800-90A DRBGs implement an automated reseeding after reaching a | |
197 | * pre-defined threshold. | |
198 | * | |
199 | * Return: seed size for the random number generator | |
200 | */ | |
17f0f4a4 NH |
201 | static inline int crypto_rng_seedsize(struct crypto_rng *tfm) |
202 | { | |
94f1bb15 | 203 | return crypto_rng_alg(tfm)->seedsize; |
17f0f4a4 NH |
204 | } |
205 | ||
206 | #endif |