tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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
36static inline struct crypto_rng *__crypto_rng_cast(struct crypto_tfm *tfm)
37{
38 return container_of(tfm, struct crypto_rng, base);
39}
40
41int crypto_rng_reset(struct crypto_rng *tfm, const u8 *seed, unsigned int slen)
42{
43 u8 *buf = NULL;
44 int err;
45
46 if (!seed && slen) {
47 buf = kmalloc(slen, GFP_KERNEL);
48 if (!buf)
49 return -ENOMEM;
50
51 get_random_bytes(buf, slen);
52 seed = buf;
53 }
54
55 err = crypto_rng_alg(tfm)->seed(tfm, seed, slen);
56
57 kzfree(buf);
58 return err;
59}
60EXPORT_SYMBOL_GPL(crypto_rng_reset);
61
62static int crypto_rng_init_tfm(struct crypto_tfm *tfm)
63{
64 return 0;
65}
66
67static unsigned int seedsize(struct crypto_alg *alg)
68{
69 struct rng_alg *ralg = container_of(alg, struct rng_alg, base);
70
71 return ralg->seedsize;
72}
73
74#ifdef CONFIG_NET
75static int crypto_rng_report(struct sk_buff *skb, struct crypto_alg *alg)
76{
77 struct crypto_report_rng rrng;
78
79 strncpy(rrng.type, "rng", sizeof(rrng.type));
80
81 rrng.seedsize = seedsize(alg);
82
83 if (nla_put(skb, CRYPTOCFGA_REPORT_RNG,
84 sizeof(struct crypto_report_rng), &rrng))
85 goto nla_put_failure;
86 return 0;
87
88nla_put_failure:
89 return -EMSGSIZE;
90}
91#else
92static int crypto_rng_report(struct sk_buff *skb, struct crypto_alg *alg)
93{
94 return -ENOSYS;
95}
96#endif
97
98static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg)
99 __maybe_unused;
100static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg)
101{
102 seq_printf(m, "type : rng\n");
103 seq_printf(m, "seedsize : %u\n", seedsize(alg));
104}
105
106static const struct crypto_type crypto_rng_type = {
107 .extsize = crypto_alg_extsize,
108 .init_tfm = crypto_rng_init_tfm,
109#ifdef CONFIG_PROC_FS
110 .show = crypto_rng_show,
111#endif
112 .report = crypto_rng_report,
113 .maskclear = ~CRYPTO_ALG_TYPE_MASK,
114 .maskset = CRYPTO_ALG_TYPE_MASK,
115 .type = CRYPTO_ALG_TYPE_RNG,
116 .tfmsize = offsetof(struct crypto_rng, base),
117};
118
119struct crypto_rng *crypto_alloc_rng(const char *alg_name, u32 type, u32 mask)
120{
121 return crypto_alloc_tfm(alg_name, &crypto_rng_type, type, mask);
122}
123EXPORT_SYMBOL_GPL(crypto_alloc_rng);
124
125int crypto_get_default_rng(void)
126{
127 struct crypto_rng *rng;
128 int err;
129
130 mutex_lock(&crypto_default_rng_lock);
131 if (!crypto_default_rng) {
132 rng = crypto_alloc_rng("stdrng", 0, 0);
133 err = PTR_ERR(rng);
134 if (IS_ERR(rng))
135 goto unlock;
136
137 err = crypto_rng_reset(rng, NULL, crypto_rng_seedsize(rng));
138 if (err) {
139 crypto_free_rng(rng);
140 goto unlock;
141 }
142
143 crypto_default_rng = rng;
144 }
145
146 crypto_default_rng_refcnt++;
147 err = 0;
148
149unlock:
150 mutex_unlock(&crypto_default_rng_lock);
151
152 return err;
153}
154EXPORT_SYMBOL_GPL(crypto_get_default_rng);
155
156void crypto_put_default_rng(void)
157{
158 mutex_lock(&crypto_default_rng_lock);
159 crypto_default_rng_refcnt--;
160 mutex_unlock(&crypto_default_rng_lock);
161}
162EXPORT_SYMBOL_GPL(crypto_put_default_rng);
163
164#if defined(CONFIG_CRYPTO_RNG) || defined(CONFIG_CRYPTO_RNG_MODULE)
165int crypto_del_default_rng(void)
166{
167 int err = -EBUSY;
168
169 mutex_lock(&crypto_default_rng_lock);
170 if (crypto_default_rng_refcnt)
171 goto out;
172
173 crypto_free_rng(crypto_default_rng);
174 crypto_default_rng = NULL;
175
176 err = 0;
177
178out:
179 mutex_unlock(&crypto_default_rng_lock);
180
181 return err;
182}
183EXPORT_SYMBOL_GPL(crypto_del_default_rng);
184#endif
185
186int crypto_register_rng(struct rng_alg *alg)
187{
188 struct crypto_alg *base = &alg->base;
189
190 if (alg->seedsize > PAGE_SIZE / 8)
191 return -EINVAL;
192
193 base->cra_type = &crypto_rng_type;
194 base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
195 base->cra_flags |= CRYPTO_ALG_TYPE_RNG;
196
197 return crypto_register_alg(base);
198}
199EXPORT_SYMBOL_GPL(crypto_register_rng);
200
201void crypto_unregister_rng(struct rng_alg *alg)
202{
203 crypto_unregister_alg(&alg->base);
204}
205EXPORT_SYMBOL_GPL(crypto_unregister_rng);
206
207int crypto_register_rngs(struct rng_alg *algs, int count)
208{
209 int i, ret;
210
211 for (i = 0; i < count; i++) {
212 ret = crypto_register_rng(algs + i);
213 if (ret)
214 goto err;
215 }
216
217 return 0;
218
219err:
220 for (--i; i >= 0; --i)
221 crypto_unregister_rng(algs + i);
222
223 return ret;
224}
225EXPORT_SYMBOL_GPL(crypto_register_rngs);
226
227void crypto_unregister_rngs(struct rng_alg *algs, int count)
228{
229 int i;
230
231 for (i = count - 1; i >= 0; --i)
232 crypto_unregister_rng(algs + i);
233}
234EXPORT_SYMBOL_GPL(crypto_unregister_rngs);
235
236MODULE_LICENSE("GPL");
237MODULE_DESCRIPTION("Random Number Generator");