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