1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * Cryptographic API. |
4 | * |
5 | * RNG operations. |
6 | * |
7 | * Copyright (c) 2008 Neil Horman <nhorman@tuxdriver.com> |
8 | * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au> |
9 | */ |
10 | |
11 | #include <crypto/internal/rng.h> |
12 | #include <linux/atomic.h> |
13 | #include <linux/cryptouser.h> |
14 | #include <linux/err.h> |
15 | #include <linux/kernel.h> |
16 | #include <linux/module.h> |
17 | #include <linux/mutex.h> |
18 | #include <linux/random.h> |
19 | #include <linux/seq_file.h> |
20 | #include <linux/slab.h> |
21 | #include <linux/string.h> |
22 | #include <net/netlink.h> |
23 | |
24 | #include "internal.h" |
25 | |
26 | static DEFINE_MUTEX(crypto_default_rng_lock); |
27 | struct crypto_rng *crypto_default_rng; |
28 | EXPORT_SYMBOL_GPL(crypto_default_rng); |
29 | static int crypto_default_rng_refcnt; |
30 | |
31 | int crypto_rng_reset(struct crypto_rng *tfm, const u8 *seed, unsigned int slen) |
32 | { |
33 | struct rng_alg *alg = crypto_rng_alg(tfm); |
34 | u8 *buf = NULL; |
35 | int err; |
36 | |
37 | if (IS_ENABLED(CONFIG_CRYPTO_STATS)) |
38 | atomic64_inc(v: &rng_get_stat(alg)->seed_cnt); |
39 | |
40 | if (!seed && slen) { |
41 | buf = kmalloc(size: slen, GFP_KERNEL); |
42 | err = -ENOMEM; |
43 | if (!buf) |
44 | goto out; |
45 | |
46 | err = get_random_bytes_wait(buf, nbytes: slen); |
47 | if (err) |
48 | goto free_buf; |
49 | seed = buf; |
50 | } |
51 | |
52 | err = alg->seed(tfm, seed, slen); |
53 | free_buf: |
54 | kfree_sensitive(objp: buf); |
55 | out: |
56 | return crypto_rng_errstat(alg, err); |
57 | } |
58 | EXPORT_SYMBOL_GPL(crypto_rng_reset); |
59 | |
60 | static int crypto_rng_init_tfm(struct crypto_tfm *tfm) |
61 | { |
62 | return 0; |
63 | } |
64 | |
65 | static unsigned int seedsize(struct crypto_alg *alg) |
66 | { |
67 | struct rng_alg *ralg = container_of(alg, struct rng_alg, base); |
68 | |
69 | return ralg->seedsize; |
70 | } |
71 | |
72 | static int __maybe_unused crypto_rng_report( |
73 | struct sk_buff *skb, struct crypto_alg *alg) |
74 | { |
75 | struct crypto_report_rng rrng; |
76 | |
77 | memset(&rrng, 0, sizeof(rrng)); |
78 | |
79 | strscpy(rrng.type, "rng" , sizeof(rrng.type)); |
80 | |
81 | rrng.seedsize = seedsize(alg); |
82 | |
83 | return nla_put(skb, attrtype: CRYPTOCFGA_REPORT_RNG, attrlen: sizeof(rrng), data: &rrng); |
84 | } |
85 | |
86 | static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg) |
87 | __maybe_unused; |
88 | static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg) |
89 | { |
90 | seq_printf(m, fmt: "type : rng\n" ); |
91 | seq_printf(m, fmt: "seedsize : %u\n" , seedsize(alg)); |
92 | } |
93 | |
94 | static int __maybe_unused crypto_rng_report_stat( |
95 | struct sk_buff *skb, struct crypto_alg *alg) |
96 | { |
97 | struct rng_alg *rng = __crypto_rng_alg(alg); |
98 | struct crypto_istat_rng *istat; |
99 | struct crypto_stat_rng rrng; |
100 | |
101 | istat = rng_get_stat(alg: rng); |
102 | |
103 | memset(&rrng, 0, sizeof(rrng)); |
104 | |
105 | strscpy(rrng.type, "rng" , sizeof(rrng.type)); |
106 | |
107 | rrng.stat_generate_cnt = atomic64_read(v: &istat->generate_cnt); |
108 | rrng.stat_generate_tlen = atomic64_read(v: &istat->generate_tlen); |
109 | rrng.stat_seed_cnt = atomic64_read(v: &istat->seed_cnt); |
110 | rrng.stat_err_cnt = atomic64_read(v: &istat->err_cnt); |
111 | |
112 | return nla_put(skb, attrtype: CRYPTOCFGA_STAT_RNG, attrlen: sizeof(rrng), data: &rrng); |
113 | } |
114 | |
115 | static const struct crypto_type crypto_rng_type = { |
116 | .extsize = crypto_alg_extsize, |
117 | .init_tfm = crypto_rng_init_tfm, |
118 | #ifdef CONFIG_PROC_FS |
119 | .show = crypto_rng_show, |
120 | #endif |
121 | #if IS_ENABLED(CONFIG_CRYPTO_USER) |
122 | .report = crypto_rng_report, |
123 | #endif |
124 | #ifdef CONFIG_CRYPTO_STATS |
125 | .report_stat = crypto_rng_report_stat, |
126 | #endif |
127 | .maskclear = ~CRYPTO_ALG_TYPE_MASK, |
128 | .maskset = CRYPTO_ALG_TYPE_MASK, |
129 | .type = CRYPTO_ALG_TYPE_RNG, |
130 | .tfmsize = offsetof(struct crypto_rng, base), |
131 | }; |
132 | |
133 | struct crypto_rng *crypto_alloc_rng(const char *alg_name, u32 type, u32 mask) |
134 | { |
135 | return crypto_alloc_tfm(alg_name, frontend: &crypto_rng_type, type, mask); |
136 | } |
137 | EXPORT_SYMBOL_GPL(crypto_alloc_rng); |
138 | |
139 | int crypto_get_default_rng(void) |
140 | { |
141 | struct crypto_rng *rng; |
142 | int err; |
143 | |
144 | mutex_lock(&crypto_default_rng_lock); |
145 | if (!crypto_default_rng) { |
146 | rng = crypto_alloc_rng("stdrng" , 0, 0); |
147 | err = PTR_ERR(ptr: rng); |
148 | if (IS_ERR(ptr: rng)) |
149 | goto unlock; |
150 | |
151 | err = crypto_rng_reset(rng, NULL, crypto_rng_seedsize(tfm: rng)); |
152 | if (err) { |
153 | crypto_free_rng(tfm: rng); |
154 | goto unlock; |
155 | } |
156 | |
157 | crypto_default_rng = rng; |
158 | } |
159 | |
160 | crypto_default_rng_refcnt++; |
161 | err = 0; |
162 | |
163 | unlock: |
164 | mutex_unlock(lock: &crypto_default_rng_lock); |
165 | |
166 | return err; |
167 | } |
168 | EXPORT_SYMBOL_GPL(crypto_get_default_rng); |
169 | |
170 | void crypto_put_default_rng(void) |
171 | { |
172 | mutex_lock(&crypto_default_rng_lock); |
173 | crypto_default_rng_refcnt--; |
174 | mutex_unlock(lock: &crypto_default_rng_lock); |
175 | } |
176 | EXPORT_SYMBOL_GPL(crypto_put_default_rng); |
177 | |
178 | #if defined(CONFIG_CRYPTO_RNG) || defined(CONFIG_CRYPTO_RNG_MODULE) |
179 | int crypto_del_default_rng(void) |
180 | { |
181 | int err = -EBUSY; |
182 | |
183 | mutex_lock(&crypto_default_rng_lock); |
184 | if (crypto_default_rng_refcnt) |
185 | goto out; |
186 | |
187 | crypto_free_rng(tfm: crypto_default_rng); |
188 | crypto_default_rng = NULL; |
189 | |
190 | err = 0; |
191 | |
192 | out: |
193 | mutex_unlock(lock: &crypto_default_rng_lock); |
194 | |
195 | return err; |
196 | } |
197 | EXPORT_SYMBOL_GPL(crypto_del_default_rng); |
198 | #endif |
199 | |
200 | int crypto_register_rng(struct rng_alg *alg) |
201 | { |
202 | struct crypto_istat_rng *istat = rng_get_stat(alg); |
203 | struct crypto_alg *base = &alg->base; |
204 | |
205 | if (alg->seedsize > PAGE_SIZE / 8) |
206 | return -EINVAL; |
207 | |
208 | base->cra_type = &crypto_rng_type; |
209 | base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK; |
210 | base->cra_flags |= CRYPTO_ALG_TYPE_RNG; |
211 | |
212 | if (IS_ENABLED(CONFIG_CRYPTO_STATS)) |
213 | memset(istat, 0, sizeof(*istat)); |
214 | |
215 | return crypto_register_alg(alg: base); |
216 | } |
217 | EXPORT_SYMBOL_GPL(crypto_register_rng); |
218 | |
219 | void crypto_unregister_rng(struct rng_alg *alg) |
220 | { |
221 | crypto_unregister_alg(alg: &alg->base); |
222 | } |
223 | EXPORT_SYMBOL_GPL(crypto_unregister_rng); |
224 | |
225 | int crypto_register_rngs(struct rng_alg *algs, int count) |
226 | { |
227 | int i, ret; |
228 | |
229 | for (i = 0; i < count; i++) { |
230 | ret = crypto_register_rng(algs + i); |
231 | if (ret) |
232 | goto err; |
233 | } |
234 | |
235 | return 0; |
236 | |
237 | err: |
238 | for (--i; i >= 0; --i) |
239 | crypto_unregister_rng(algs + i); |
240 | |
241 | return ret; |
242 | } |
243 | EXPORT_SYMBOL_GPL(crypto_register_rngs); |
244 | |
245 | void crypto_unregister_rngs(struct rng_alg *algs, int count) |
246 | { |
247 | int i; |
248 | |
249 | for (i = count - 1; i >= 0; --i) |
250 | crypto_unregister_rng(algs + i); |
251 | } |
252 | EXPORT_SYMBOL_GPL(crypto_unregister_rngs); |
253 | |
254 | MODULE_LICENSE("GPL" ); |
255 | MODULE_DESCRIPTION("Random Number Generator" ); |
256 | |