Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
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
26static DEFINE_MUTEX(crypto_default_rng_lock);
27struct crypto_rng *crypto_default_rng;
28EXPORT_SYMBOL_GPL(crypto_default_rng);
29static int crypto_default_rng_refcnt;
30
31int crypto_rng_reset(struct crypto_rng *tfm, const u8 *seed, unsigned int slen)
32{
33 u8 *buf = NULL;
34 int err;
35
36 if (!seed && slen) {
37 buf = kmalloc(slen, GFP_KERNEL);
38 if (!buf)
39 return -ENOMEM;
40
41 err = get_random_bytes_wait(buf, slen);
42 if (err)
43 goto out;
44 seed = buf;
45 }
46
47 err = crypto_rng_alg(tfm)->seed(tfm, seed, slen);
48out:
49 kfree_sensitive(buf);
50 return err;
51}
52EXPORT_SYMBOL_GPL(crypto_rng_reset);
53
54static int crypto_rng_init_tfm(struct crypto_tfm *tfm)
55{
56 return 0;
57}
58
59static unsigned int seedsize(struct crypto_alg *alg)
60{
61 struct rng_alg *ralg = container_of(alg, struct rng_alg, base);
62
63 return ralg->seedsize;
64}
65
66static int __maybe_unused crypto_rng_report(
67 struct sk_buff *skb, struct crypto_alg *alg)
68{
69 struct crypto_report_rng rrng;
70
71 memset(&rrng, 0, sizeof(rrng));
72
73 strscpy(rrng.type, "rng", sizeof(rrng.type));
74
75 rrng.seedsize = seedsize(alg);
76
77 return nla_put(skb, CRYPTOCFGA_REPORT_RNG, sizeof(rrng), &rrng);
78}
79
80static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg)
81 __maybe_unused;
82static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg)
83{
84 seq_printf(m, "type : rng\n");
85 seq_printf(m, "seedsize : %u\n", seedsize(alg));
86}
87
88static const struct crypto_type crypto_rng_type = {
89 .extsize = crypto_alg_extsize,
90 .init_tfm = crypto_rng_init_tfm,
91#ifdef CONFIG_PROC_FS
92 .show = crypto_rng_show,
93#endif
94#if IS_ENABLED(CONFIG_CRYPTO_USER)
95 .report = crypto_rng_report,
96#endif
97 .maskclear = ~CRYPTO_ALG_TYPE_MASK,
98 .maskset = CRYPTO_ALG_TYPE_MASK,
99 .type = CRYPTO_ALG_TYPE_RNG,
100 .tfmsize = offsetof(struct crypto_rng, base),
101 .algsize = offsetof(struct rng_alg, base),
102};
103
104struct crypto_rng *crypto_alloc_rng(const char *alg_name, u32 type, u32 mask)
105{
106 return crypto_alloc_tfm(alg_name, &crypto_rng_type, type, mask);
107}
108EXPORT_SYMBOL_GPL(crypto_alloc_rng);
109
110int crypto_get_default_rng(void)
111{
112 struct crypto_rng *rng;
113 int err;
114
115 mutex_lock(&crypto_default_rng_lock);
116 if (!crypto_default_rng) {
117 rng = crypto_alloc_rng("stdrng", 0, 0);
118 err = PTR_ERR(rng);
119 if (IS_ERR(rng))
120 goto unlock;
121
122 err = crypto_rng_reset(rng, NULL, crypto_rng_seedsize(rng));
123 if (err) {
124 crypto_free_rng(rng);
125 goto unlock;
126 }
127
128 crypto_default_rng = rng;
129 }
130
131 crypto_default_rng_refcnt++;
132 err = 0;
133
134unlock:
135 mutex_unlock(&crypto_default_rng_lock);
136
137 return err;
138}
139EXPORT_SYMBOL_GPL(crypto_get_default_rng);
140
141void crypto_put_default_rng(void)
142{
143 mutex_lock(&crypto_default_rng_lock);
144 crypto_default_rng_refcnt--;
145 mutex_unlock(&crypto_default_rng_lock);
146}
147EXPORT_SYMBOL_GPL(crypto_put_default_rng);
148
149#if defined(CONFIG_CRYPTO_RNG) || defined(CONFIG_CRYPTO_RNG_MODULE)
150int crypto_del_default_rng(void)
151{
152 int err = -EBUSY;
153
154 mutex_lock(&crypto_default_rng_lock);
155 if (crypto_default_rng_refcnt)
156 goto out;
157
158 crypto_free_rng(crypto_default_rng);
159 crypto_default_rng = NULL;
160
161 err = 0;
162
163out:
164 mutex_unlock(&crypto_default_rng_lock);
165
166 return err;
167}
168EXPORT_SYMBOL_GPL(crypto_del_default_rng);
169#endif
170
171static void rng_default_set_ent(struct crypto_rng *tfm, const u8 *data,
172 unsigned int len)
173{
174}
175
176int crypto_register_rng(struct rng_alg *alg)
177{
178 struct crypto_alg *base = &alg->base;
179
180 if (alg->seedsize > PAGE_SIZE / 8)
181 return -EINVAL;
182
183 base->cra_type = &crypto_rng_type;
184 base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
185 base->cra_flags |= CRYPTO_ALG_TYPE_RNG;
186
187 if (!alg->set_ent)
188 alg->set_ent = rng_default_set_ent;
189
190 return crypto_register_alg(base);
191}
192EXPORT_SYMBOL_GPL(crypto_register_rng);
193
194void crypto_unregister_rng(struct rng_alg *alg)
195{
196 crypto_unregister_alg(&alg->base);
197}
198EXPORT_SYMBOL_GPL(crypto_unregister_rng);
199
200int crypto_register_rngs(struct rng_alg *algs, int count)
201{
202 int i, ret;
203
204 for (i = 0; i < count; i++) {
205 ret = crypto_register_rng(algs + i);
206 if (ret)
207 goto err;
208 }
209
210 return 0;
211
212err:
213 for (--i; i >= 0; --i)
214 crypto_unregister_rng(algs + i);
215
216 return ret;
217}
218EXPORT_SYMBOL_GPL(crypto_register_rngs);
219
220void crypto_unregister_rngs(struct rng_alg *algs, int count)
221{
222 int i;
223
224 for (i = count - 1; i >= 0; --i)
225 crypto_unregister_rng(algs + i);
226}
227EXPORT_SYMBOL_GPL(crypto_unregister_rngs);
228
229MODULE_LICENSE("GPL");
230MODULE_DESCRIPTION("Random Number Generator");