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2874c5fd 1// SPDX-License-Identifier: GPL-2.0-or-later
17f0f4a4
NH
2/*
3 * Cryptographic API.
4 *
5 * RNG operations.
6 *
7 * Copyright (c) 2008 Neil Horman <nhorman@tuxdriver.com>
94f1bb15 8 * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
17f0f4a4
NH
9 */
10
60063497 11#include <linux/atomic.h>
17f0f4a4
NH
12#include <crypto/internal/rng.h>
13#include <linux/err.h>
14#include <linux/module.h>
15#include <linux/mutex.h>
16#include <linux/random.h>
17#include <linux/seq_file.h>
5a0e3ad6 18#include <linux/slab.h>
17f0f4a4 19#include <linux/string.h>
792608e9 20#include <linux/cryptouser.h>
d8c34b94 21#include <linux/compiler.h>
792608e9 22#include <net/netlink.h>
17f0f4a4 23
d0e83059
HX
24#include "internal.h"
25
17f0f4a4
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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
3c5d8fa9 31int crypto_rng_reset(struct crypto_rng *tfm, const u8 *seed, unsigned int slen)
17f0f4a4 32{
f7d76e05 33 struct crypto_alg *alg = tfm->base.__crt_alg;
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NH
34 u8 *buf = NULL;
35 int err;
36
f7d76e05 37 crypto_stats_get(alg);
17f0f4a4
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38 if (!seed && slen) {
39 buf = kmalloc(slen, GFP_KERNEL);
eed74b3e
DC
40 if (!buf) {
41 crypto_alg_put(alg);
17f0f4a4 42 return -ENOMEM;
eed74b3e 43 }
17f0f4a4 44
c2176f00 45 err = get_random_bytes_wait(buf, slen);
eed74b3e
DC
46 if (err) {
47 crypto_alg_put(alg);
c2176f00 48 goto out;
eed74b3e 49 }
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50 seed = buf;
51 }
52
94f1bb15 53 err = crypto_rng_alg(tfm)->seed(tfm, seed, slen);
f7d76e05 54 crypto_stats_rng_seed(alg, err);
c2176f00 55out:
453431a5 56 kfree_sensitive(buf);
17f0f4a4
NH
57 return err;
58}
3c5d8fa9 59EXPORT_SYMBOL_GPL(crypto_rng_reset);
17f0f4a4 60
d0e83059 61static int crypto_rng_init_tfm(struct crypto_tfm *tfm)
17f0f4a4 62{
17f0f4a4
NH
63 return 0;
64}
65
acec27ff
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66static unsigned int seedsize(struct crypto_alg *alg)
67{
68 struct rng_alg *ralg = container_of(alg, struct rng_alg, base);
69
94f1bb15 70 return ralg->seedsize;
acec27ff
HX
71}
72
3acc8473 73#ifdef CONFIG_NET
792608e9
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74static int crypto_rng_report(struct sk_buff *skb, struct crypto_alg *alg)
75{
76 struct crypto_report_rng rrng;
77
37db69e0 78 memset(&rrng, 0, sizeof(rrng));
792608e9 79
37db69e0 80 strscpy(rrng.type, "rng", sizeof(rrng.type));
792608e9 81
37db69e0 82 rrng.seedsize = seedsize(alg);
792608e9 83
37db69e0 84 return nla_put(skb, CRYPTOCFGA_REPORT_RNG, sizeof(rrng), &rrng);
792608e9 85}
3acc8473
HX
86#else
87static int crypto_rng_report(struct sk_buff *skb, struct crypto_alg *alg)
88{
89 return -ENOSYS;
90}
91#endif
792608e9 92
17f0f4a4 93static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg)
d8c34b94 94 __maybe_unused;
17f0f4a4
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95static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg)
96{
97 seq_printf(m, "type : rng\n");
acec27ff 98 seq_printf(m, "seedsize : %u\n", seedsize(alg));
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99}
100
94f1bb15 101static const struct crypto_type crypto_rng_type = {
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102 .extsize = crypto_alg_extsize,
103 .init_tfm = crypto_rng_init_tfm,
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104#ifdef CONFIG_PROC_FS
105 .show = crypto_rng_show,
106#endif
792608e9 107 .report = crypto_rng_report,
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108 .maskclear = ~CRYPTO_ALG_TYPE_MASK,
109 .maskset = CRYPTO_ALG_TYPE_MASK,
110 .type = CRYPTO_ALG_TYPE_RNG,
111 .tfmsize = offsetof(struct crypto_rng, base),
17f0f4a4 112};
17f0f4a4 113
d0e83059
HX
114struct crypto_rng *crypto_alloc_rng(const char *alg_name, u32 type, u32 mask)
115{
116 return crypto_alloc_tfm(alg_name, &crypto_rng_type, type, mask);
117}
118EXPORT_SYMBOL_GPL(crypto_alloc_rng);
119
17f0f4a4
NH
120int crypto_get_default_rng(void)
121{
122 struct crypto_rng *rng;
123 int err;
124
125 mutex_lock(&crypto_default_rng_lock);
126 if (!crypto_default_rng) {
127 rng = crypto_alloc_rng("stdrng", 0, 0);
128 err = PTR_ERR(rng);
129 if (IS_ERR(rng))
130 goto unlock;
131
132 err = crypto_rng_reset(rng, NULL, crypto_rng_seedsize(rng));
133 if (err) {
134 crypto_free_rng(rng);
135 goto unlock;
136 }
137
138 crypto_default_rng = rng;
139 }
140
141 crypto_default_rng_refcnt++;
142 err = 0;
143
144unlock:
145 mutex_unlock(&crypto_default_rng_lock);
146
147 return err;
148}
149EXPORT_SYMBOL_GPL(crypto_get_default_rng);
150
151void crypto_put_default_rng(void)
152{
153 mutex_lock(&crypto_default_rng_lock);
7cecadb7 154 crypto_default_rng_refcnt--;
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155 mutex_unlock(&crypto_default_rng_lock);
156}
157EXPORT_SYMBOL_GPL(crypto_put_default_rng);
158
7cecadb7
HX
159#if defined(CONFIG_CRYPTO_RNG) || defined(CONFIG_CRYPTO_RNG_MODULE)
160int crypto_del_default_rng(void)
161{
162 int err = -EBUSY;
163
164 mutex_lock(&crypto_default_rng_lock);
165 if (crypto_default_rng_refcnt)
166 goto out;
167
168 crypto_free_rng(crypto_default_rng);
169 crypto_default_rng = NULL;
170
171 err = 0;
172
173out:
174 mutex_unlock(&crypto_default_rng_lock);
175
176 return err;
177}
178EXPORT_SYMBOL_GPL(crypto_del_default_rng);
179#endif
180
acec27ff
HX
181int crypto_register_rng(struct rng_alg *alg)
182{
183 struct crypto_alg *base = &alg->base;
184
185 if (alg->seedsize > PAGE_SIZE / 8)
186 return -EINVAL;
187
188 base->cra_type = &crypto_rng_type;
189 base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
190 base->cra_flags |= CRYPTO_ALG_TYPE_RNG;
191
192 return crypto_register_alg(base);
193}
194EXPORT_SYMBOL_GPL(crypto_register_rng);
195
196void crypto_unregister_rng(struct rng_alg *alg)
197{
198 crypto_unregister_alg(&alg->base);
199}
200EXPORT_SYMBOL_GPL(crypto_unregister_rng);
201
881cd6c5
HX
202int crypto_register_rngs(struct rng_alg *algs, int count)
203{
204 int i, ret;
205
206 for (i = 0; i < count; i++) {
207 ret = crypto_register_rng(algs + i);
208 if (ret)
209 goto err;
210 }
211
212 return 0;
213
214err:
215 for (--i; i >= 0; --i)
216 crypto_unregister_rng(algs + i);
217
218 return ret;
219}
220EXPORT_SYMBOL_GPL(crypto_register_rngs);
221
222void crypto_unregister_rngs(struct rng_alg *algs, int count)
223{
224 int i;
225
226 for (i = count - 1; i >= 0; --i)
227 crypto_unregister_rng(algs + i);
228}
229EXPORT_SYMBOL_GPL(crypto_unregister_rngs);
230
17f0f4a4 231MODULE_LICENSE("GPL");
a8ccc393 232MODULE_DESCRIPTION("Random Number Generator");