Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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 <linux/compiler.h>
27#include <net/netlink.h>
28
29#include "internal.h"
30
31static DEFINE_MUTEX(crypto_default_rng_lock);
32struct crypto_rng *crypto_default_rng;
33EXPORT_SYMBOL_GPL(crypto_default_rng);
34static int crypto_default_rng_refcnt;
35
36int crypto_rng_reset(struct crypto_rng *tfm, const u8 *seed, unsigned int slen)
37{
38 u8 *buf = NULL;
39 int err;
40
41 if (!seed && slen) {
42 buf = kmalloc(slen, GFP_KERNEL);
43 if (!buf)
44 return -ENOMEM;
45
46 err = get_random_bytes_wait(buf, slen);
47 if (err)
48 goto out;
49 seed = buf;
50 }
51
52 err = crypto_rng_alg(tfm)->seed(tfm, seed, slen);
53out:
54 kzfree(buf);
55 return err;
56}
57EXPORT_SYMBOL_GPL(crypto_rng_reset);
58
59static int crypto_rng_init_tfm(struct crypto_tfm *tfm)
60{
61 return 0;
62}
63
64static unsigned int seedsize(struct crypto_alg *alg)
65{
66 struct rng_alg *ralg = container_of(alg, struct rng_alg, base);
67
68 return ralg->seedsize;
69}
70
71#ifdef CONFIG_NET
72static int crypto_rng_report(struct sk_buff *skb, struct crypto_alg *alg)
73{
74 struct crypto_report_rng rrng;
75
76 strncpy(rrng.type, "rng", sizeof(rrng.type));
77
78 rrng.seedsize = seedsize(alg);
79
80 if (nla_put(skb, CRYPTOCFGA_REPORT_RNG,
81 sizeof(struct crypto_report_rng), &rrng))
82 goto nla_put_failure;
83 return 0;
84
85nla_put_failure:
86 return -EMSGSIZE;
87}
88#else
89static int crypto_rng_report(struct sk_buff *skb, struct crypto_alg *alg)
90{
91 return -ENOSYS;
92}
93#endif
94
95static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg)
96 __maybe_unused;
97static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg)
98{
99 seq_printf(m, "type : rng\n");
100 seq_printf(m, "seedsize : %u\n", seedsize(alg));
101}
102
103static const struct crypto_type crypto_rng_type = {
104 .extsize = crypto_alg_extsize,
105 .init_tfm = crypto_rng_init_tfm,
106#ifdef CONFIG_PROC_FS
107 .show = crypto_rng_show,
108#endif
109 .report = crypto_rng_report,
110 .maskclear = ~CRYPTO_ALG_TYPE_MASK,
111 .maskset = CRYPTO_ALG_TYPE_MASK,
112 .type = CRYPTO_ALG_TYPE_RNG,
113 .tfmsize = offsetof(struct crypto_rng, base),
114};
115
116struct crypto_rng *crypto_alloc_rng(const char *alg_name, u32 type, u32 mask)
117{
118 return crypto_alloc_tfm(alg_name, &crypto_rng_type, type, mask);
119}
120EXPORT_SYMBOL_GPL(crypto_alloc_rng);
121
122int crypto_get_default_rng(void)
123{
124 struct crypto_rng *rng;
125 int err;
126
127 mutex_lock(&crypto_default_rng_lock);
128 if (!crypto_default_rng) {
129 rng = crypto_alloc_rng("stdrng", 0, 0);
130 err = PTR_ERR(rng);
131 if (IS_ERR(rng))
132 goto unlock;
133
134 err = crypto_rng_reset(rng, NULL, crypto_rng_seedsize(rng));
135 if (err) {
136 crypto_free_rng(rng);
137 goto unlock;
138 }
139
140 crypto_default_rng = rng;
141 }
142
143 crypto_default_rng_refcnt++;
144 err = 0;
145
146unlock:
147 mutex_unlock(&crypto_default_rng_lock);
148
149 return err;
150}
151EXPORT_SYMBOL_GPL(crypto_get_default_rng);
152
153void crypto_put_default_rng(void)
154{
155 mutex_lock(&crypto_default_rng_lock);
156 crypto_default_rng_refcnt--;
157 mutex_unlock(&crypto_default_rng_lock);
158}
159EXPORT_SYMBOL_GPL(crypto_put_default_rng);
160
161#if defined(CONFIG_CRYPTO_RNG) || defined(CONFIG_CRYPTO_RNG_MODULE)
162int crypto_del_default_rng(void)
163{
164 int err = -EBUSY;
165
166 mutex_lock(&crypto_default_rng_lock);
167 if (crypto_default_rng_refcnt)
168 goto out;
169
170 crypto_free_rng(crypto_default_rng);
171 crypto_default_rng = NULL;
172
173 err = 0;
174
175out:
176 mutex_unlock(&crypto_default_rng_lock);
177
178 return err;
179}
180EXPORT_SYMBOL_GPL(crypto_del_default_rng);
181#endif
182
183int crypto_register_rng(struct rng_alg *alg)
184{
185 struct crypto_alg *base = &alg->base;
186
187 if (alg->seedsize > PAGE_SIZE / 8)
188 return -EINVAL;
189
190 base->cra_type = &crypto_rng_type;
191 base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
192 base->cra_flags |= CRYPTO_ALG_TYPE_RNG;
193
194 return crypto_register_alg(base);
195}
196EXPORT_SYMBOL_GPL(crypto_register_rng);
197
198void crypto_unregister_rng(struct rng_alg *alg)
199{
200 crypto_unregister_alg(&alg->base);
201}
202EXPORT_SYMBOL_GPL(crypto_unregister_rng);
203
204int crypto_register_rngs(struct rng_alg *algs, int count)
205{
206 int i, ret;
207
208 for (i = 0; i < count; i++) {
209 ret = crypto_register_rng(algs + i);
210 if (ret)
211 goto err;
212 }
213
214 return 0;
215
216err:
217 for (--i; i >= 0; --i)
218 crypto_unregister_rng(algs + i);
219
220 return ret;
221}
222EXPORT_SYMBOL_GPL(crypto_register_rngs);
223
224void crypto_unregister_rngs(struct rng_alg *algs, int count)
225{
226 int i;
227
228 for (i = count - 1; i >= 0; --i)
229 crypto_unregister_rng(algs + i);
230}
231EXPORT_SYMBOL_GPL(crypto_unregister_rngs);
232
233MODULE_LICENSE("GPL");
234MODULE_DESCRIPTION("Random Number Generator");