blob: b81cffb13babc35cc2203ce5355ac6a04b18c5c4
1 | /* |
2 | * Cryptographic API. |
3 | * |
4 | * RNG operations. |
5 | * |
6 | * Copyright (c) 2008 Neil Horman <nhorman@tuxdriver.com> |
7 | * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au> |
8 | * |
9 | * This program is free software; you can redistribute it and/or modify it |
10 | * under the terms of the GNU General Public License as published by the Free |
11 | * Software Foundation; either version 2 of the License, or (at your option) |
12 | * any later version. |
13 | * |
14 | */ |
15 | |
16 | #include <linux/atomic.h> |
17 | #include <crypto/internal/rng.h> |
18 | #include <linux/err.h> |
19 | #include <linux/module.h> |
20 | #include <linux/mutex.h> |
21 | #include <linux/random.h> |
22 | #include <linux/seq_file.h> |
23 | #include <linux/slab.h> |
24 | #include <linux/string.h> |
25 | #include <linux/cryptouser.h> |
26 | #include <net/netlink.h> |
27 | |
28 | #include "internal.h" |
29 | |
30 | static DEFINE_MUTEX(crypto_default_rng_lock); |
31 | struct crypto_rng *crypto_default_rng; |
32 | EXPORT_SYMBOL_GPL(crypto_default_rng); |
33 | static int crypto_default_rng_refcnt; |
34 | |
35 | static inline struct crypto_rng *__crypto_rng_cast(struct crypto_tfm *tfm) |
36 | { |
37 | return container_of(tfm, struct crypto_rng, base); |
38 | } |
39 | |
40 | int crypto_rng_reset(struct crypto_rng *tfm, const u8 *seed, unsigned int slen) |
41 | { |
42 | u8 *buf = NULL; |
43 | int err; |
44 | |
45 | if (!seed && slen) { |
46 | buf = kmalloc(slen, GFP_KERNEL); |
47 | if (!buf) |
48 | return -ENOMEM; |
49 | |
50 | get_random_bytes(buf, slen); |
51 | seed = buf; |
52 | } |
53 | |
54 | err = crypto_rng_alg(tfm)->seed(tfm, seed, slen); |
55 | |
56 | kzfree(buf); |
57 | return err; |
58 | } |
59 | EXPORT_SYMBOL_GPL(crypto_rng_reset); |
60 | |
61 | static int crypto_rng_init_tfm(struct crypto_tfm *tfm) |
62 | { |
63 | return 0; |
64 | } |
65 | |
66 | static unsigned int seedsize(struct crypto_alg *alg) |
67 | { |
68 | struct rng_alg *ralg = container_of(alg, struct rng_alg, base); |
69 | |
70 | return ralg->seedsize; |
71 | } |
72 | |
73 | #ifdef CONFIG_NET |
74 | static int crypto_rng_report(struct sk_buff *skb, struct crypto_alg *alg) |
75 | { |
76 | struct crypto_report_rng rrng; |
77 | |
78 | strncpy(rrng.type, "rng", sizeof(rrng.type)); |
79 | |
80 | rrng.seedsize = seedsize(alg); |
81 | |
82 | if (nla_put(skb, CRYPTOCFGA_REPORT_RNG, |
83 | sizeof(struct crypto_report_rng), &rrng)) |
84 | goto nla_put_failure; |
85 | return 0; |
86 | |
87 | nla_put_failure: |
88 | return -EMSGSIZE; |
89 | } |
90 | #else |
91 | static int crypto_rng_report(struct sk_buff *skb, struct crypto_alg *alg) |
92 | { |
93 | return -ENOSYS; |
94 | } |
95 | #endif |
96 | |
97 | static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg) |
98 | __attribute__ ((unused)); |
99 | static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg) |
100 | { |
101 | seq_printf(m, "type : rng\n"); |
102 | seq_printf(m, "seedsize : %u\n", seedsize(alg)); |
103 | } |
104 | |
105 | static const struct crypto_type crypto_rng_type = { |
106 | .extsize = crypto_alg_extsize, |
107 | .init_tfm = crypto_rng_init_tfm, |
108 | #ifdef CONFIG_PROC_FS |
109 | .show = crypto_rng_show, |
110 | #endif |
111 | .report = crypto_rng_report, |
112 | .maskclear = ~CRYPTO_ALG_TYPE_MASK, |
113 | .maskset = CRYPTO_ALG_TYPE_MASK, |
114 | .type = CRYPTO_ALG_TYPE_RNG, |
115 | .tfmsize = offsetof(struct crypto_rng, base), |
116 | }; |
117 | |
118 | struct crypto_rng *crypto_alloc_rng(const char *alg_name, u32 type, u32 mask) |
119 | { |
120 | return crypto_alloc_tfm(alg_name, &crypto_rng_type, type, mask); |
121 | } |
122 | EXPORT_SYMBOL_GPL(crypto_alloc_rng); |
123 | |
124 | int crypto_get_default_rng(void) |
125 | { |
126 | struct crypto_rng *rng; |
127 | int err; |
128 | |
129 | mutex_lock(&crypto_default_rng_lock); |
130 | if (!crypto_default_rng) { |
131 | rng = crypto_alloc_rng("stdrng", 0, 0); |
132 | err = PTR_ERR(rng); |
133 | if (IS_ERR(rng)) |
134 | goto unlock; |
135 | |
136 | err = crypto_rng_reset(rng, NULL, crypto_rng_seedsize(rng)); |
137 | if (err) { |
138 | crypto_free_rng(rng); |
139 | goto unlock; |
140 | } |
141 | |
142 | crypto_default_rng = rng; |
143 | } |
144 | |
145 | crypto_default_rng_refcnt++; |
146 | err = 0; |
147 | |
148 | unlock: |
149 | mutex_unlock(&crypto_default_rng_lock); |
150 | |
151 | return err; |
152 | } |
153 | EXPORT_SYMBOL_GPL(crypto_get_default_rng); |
154 | |
155 | void crypto_put_default_rng(void) |
156 | { |
157 | mutex_lock(&crypto_default_rng_lock); |
158 | crypto_default_rng_refcnt--; |
159 | mutex_unlock(&crypto_default_rng_lock); |
160 | } |
161 | EXPORT_SYMBOL_GPL(crypto_put_default_rng); |
162 | |
163 | #if defined(CONFIG_CRYPTO_RNG) || defined(CONFIG_CRYPTO_RNG_MODULE) |
164 | int crypto_del_default_rng(void) |
165 | { |
166 | int err = -EBUSY; |
167 | |
168 | mutex_lock(&crypto_default_rng_lock); |
169 | if (crypto_default_rng_refcnt) |
170 | goto out; |
171 | |
172 | crypto_free_rng(crypto_default_rng); |
173 | crypto_default_rng = NULL; |
174 | |
175 | err = 0; |
176 | |
177 | out: |
178 | mutex_unlock(&crypto_default_rng_lock); |
179 | |
180 | return err; |
181 | } |
182 | EXPORT_SYMBOL_GPL(crypto_del_default_rng); |
183 | #endif |
184 | |
185 | int crypto_register_rng(struct rng_alg *alg) |
186 | { |
187 | struct crypto_alg *base = &alg->base; |
188 | |
189 | if (alg->seedsize > PAGE_SIZE / 8) |
190 | return -EINVAL; |
191 | |
192 | base->cra_type = &crypto_rng_type; |
193 | base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK; |
194 | base->cra_flags |= CRYPTO_ALG_TYPE_RNG; |
195 | |
196 | return crypto_register_alg(base); |
197 | } |
198 | EXPORT_SYMBOL_GPL(crypto_register_rng); |
199 | |
200 | void crypto_unregister_rng(struct rng_alg *alg) |
201 | { |
202 | crypto_unregister_alg(&alg->base); |
203 | } |
204 | EXPORT_SYMBOL_GPL(crypto_unregister_rng); |
205 | |
206 | int crypto_register_rngs(struct rng_alg *algs, int count) |
207 | { |
208 | int i, ret; |
209 | |
210 | for (i = 0; i < count; i++) { |
211 | ret = crypto_register_rng(algs + i); |
212 | if (ret) |
213 | goto err; |
214 | } |
215 | |
216 | return 0; |
217 | |
218 | err: |
219 | for (--i; i >= 0; --i) |
220 | crypto_unregister_rng(algs + i); |
221 | |
222 | return ret; |
223 | } |
224 | EXPORT_SYMBOL_GPL(crypto_register_rngs); |
225 | |
226 | void crypto_unregister_rngs(struct rng_alg *algs, int count) |
227 | { |
228 | int i; |
229 | |
230 | for (i = count - 1; i >= 0; --i) |
231 | crypto_unregister_rng(algs + i); |
232 | } |
233 | EXPORT_SYMBOL_GPL(crypto_unregister_rngs); |
234 | |
235 | MODULE_LICENSE("GPL"); |
236 | MODULE_DESCRIPTION("Random Number Generator"); |
237 |