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 | |
16 | struct 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 | */ |
25 | struct 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 | */ |
58 | struct 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 | |
75 | struct crypto_rng { |
76 | struct crypto_tfm base; |
77 | }; |
78 | |
79 | extern struct crypto_rng *crypto_default_rng; |
80 | |
81 | int crypto_get_default_rng(void); |
82 | void 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 | */ |
111 | struct crypto_rng *crypto_alloc_rng(const char *alg_name, u32 type, u32 mask); |
112 | |
113 | static inline struct crypto_tfm *crypto_rng_tfm(struct crypto_rng *tfm) |
114 | { |
115 | return &tfm->base; |
116 | } |
117 | |
118 | static 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 | */ |
131 | static inline struct rng_alg *crypto_rng_alg(struct crypto_rng *tfm) |
132 | { |
133 | return __crypto_rng_alg(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 | */ |
142 | static inline void crypto_free_rng(struct crypto_rng *tfm) |
143 | { |
144 | crypto_destroy_tfm(mem: tfm, tfm: crypto_rng_tfm(tfm)); |
145 | } |
146 | |
147 | static 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 | |
156 | static 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(v: &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 | */ |
181 | static 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(v: &istat->generate_cnt); |
191 | atomic64_add(i: dlen, v: &istat->generate_tlen); |
192 | } |
193 | |
194 | return crypto_rng_errstat(alg, |
195 | err: 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 | */ |
209 | static inline int crypto_rng_get_bytes(struct crypto_rng *tfm, |
210 | u8 *rdata, unsigned int dlen) |
211 | { |
212 | return crypto_rng_generate(tfm, NULL, slen: 0, dst: 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 | */ |
232 | int 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 | */ |
247 | static inline int crypto_rng_seedsize(struct crypto_rng *tfm) |
248 | { |
249 | return crypto_rng_alg(tfm)->seedsize; |
250 | } |
251 | |
252 | #endif |
253 | |