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 <net/netlink.h>
27
28#include "internal.h"
29
30static DEFINE_MUTEX(crypto_default_rng_lock);
31struct crypto_rng *crypto_default_rng;
32EXPORT_SYMBOL_GPL(crypto_default_rng);
33static int crypto_default_rng_refcnt;
34
35static inline struct crypto_rng *__crypto_rng_cast(struct crypto_tfm *tfm)
36{
37 return container_of(tfm, struct crypto_rng, base);
38}
39
40int crypto_rng_reset(struct crypto_rng *tfm, const u8 *seed, unsigned int slen)
41{
42 u8 *buf = NULL;
43 int err;
44
45 if (!seed && slen) {
46 buf = kmalloc(slen, GFP_KERNEL);
47 if (!buf)
48 return -ENOMEM;
49
50 get_random_bytes(buf, slen);
51 seed = buf;
52 }
53
54 err = crypto_rng_alg(tfm)->seed(tfm, seed, slen);
55
56 kzfree(buf);
57 return err;
58}
59EXPORT_SYMBOL_GPL(crypto_rng_reset);
60
61static int crypto_rng_init_tfm(struct crypto_tfm *tfm)
62{
63 return 0;
64}
65
66static unsigned int seedsize(struct crypto_alg *alg)
67{
68 struct rng_alg *ralg = container_of(alg, struct rng_alg, base);
69
70 return ralg->seedsize;
71}
72
73#ifdef CONFIG_NET
74static int crypto_rng_report(struct sk_buff *skb, struct crypto_alg *alg)
75{
76 struct crypto_report_rng rrng;
77
78 strncpy(rrng.type, "rng", sizeof(rrng.type));
79
80 rrng.seedsize = seedsize(alg);
81
82 if (nla_put(skb, CRYPTOCFGA_REPORT_RNG,
83 sizeof(struct crypto_report_rng), &rrng))
84 goto nla_put_failure;
85 return 0;
86
87nla_put_failure:
88 return -EMSGSIZE;
89}
90#else
91static int crypto_rng_report(struct sk_buff *skb, struct crypto_alg *alg)
92{
93 return -ENOSYS;
94}
95#endif
96
97static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg)
98 __attribute__ ((unused));
99static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg)
100{
101 seq_printf(m, "type : rng\n");
102 seq_printf(m, "seedsize : %u\n", seedsize(alg));
103}
104
105static const struct crypto_type crypto_rng_type = {
106 .extsize = crypto_alg_extsize,
107 .init_tfm = crypto_rng_init_tfm,
108#ifdef CONFIG_PROC_FS
109 .show = crypto_rng_show,
110#endif
111 .report = crypto_rng_report,
112 .maskclear = ~CRYPTO_ALG_TYPE_MASK,
113 .maskset = CRYPTO_ALG_TYPE_MASK,
114 .type = CRYPTO_ALG_TYPE_RNG,
115 .tfmsize = offsetof(struct crypto_rng, base),
116};
117
118struct crypto_rng *crypto_alloc_rng(const char *alg_name, u32 type, u32 mask)
119{
120 return crypto_alloc_tfm(alg_name, &crypto_rng_type, type, mask);
121}
122EXPORT_SYMBOL_GPL(crypto_alloc_rng);
123
124int crypto_get_default_rng(void)
125{
126 struct crypto_rng *rng;
127 int err;
128
129 mutex_lock(&crypto_default_rng_lock);
130 if (!crypto_default_rng) {
131 rng = crypto_alloc_rng("stdrng", 0, 0);
132 err = PTR_ERR(rng);
133 if (IS_ERR(rng))
134 goto unlock;
135
136 err = crypto_rng_reset(rng, NULL, crypto_rng_seedsize(rng));
137 if (err) {
138 crypto_free_rng(rng);
139 goto unlock;
140 }
141
142 crypto_default_rng = rng;
143 }
144
145 crypto_default_rng_refcnt++;
146 err = 0;
147
148unlock:
149 mutex_unlock(&crypto_default_rng_lock);
150
151 return err;
152}
153EXPORT_SYMBOL_GPL(crypto_get_default_rng);
154
155void crypto_put_default_rng(void)
156{
157 mutex_lock(&crypto_default_rng_lock);
158 crypto_default_rng_refcnt--;
159 mutex_unlock(&crypto_default_rng_lock);
160}
161EXPORT_SYMBOL_GPL(crypto_put_default_rng);
162
163#if defined(CONFIG_CRYPTO_RNG) || defined(CONFIG_CRYPTO_RNG_MODULE)
164int crypto_del_default_rng(void)
165{
166 int err = -EBUSY;
167
168 mutex_lock(&crypto_default_rng_lock);
169 if (crypto_default_rng_refcnt)
170 goto out;
171
172 crypto_free_rng(crypto_default_rng);
173 crypto_default_rng = NULL;
174
175 err = 0;
176
177out:
178 mutex_unlock(&crypto_default_rng_lock);
179
180 return err;
181}
182EXPORT_SYMBOL_GPL(crypto_del_default_rng);
183#endif
184
185int crypto_register_rng(struct rng_alg *alg)
186{
187 struct crypto_alg *base = &alg->base;
188
189 if (alg->seedsize > PAGE_SIZE / 8)
190 return -EINVAL;
191
192 base->cra_type = &crypto_rng_type;
193 base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
194 base->cra_flags |= CRYPTO_ALG_TYPE_RNG;
195
196 return crypto_register_alg(base);
197}
198EXPORT_SYMBOL_GPL(crypto_register_rng);
199
200void crypto_unregister_rng(struct rng_alg *alg)
201{
202 crypto_unregister_alg(&alg->base);
203}
204EXPORT_SYMBOL_GPL(crypto_unregister_rng);
205
206int crypto_register_rngs(struct rng_alg *algs, int count)
207{
208 int i, ret;
209
210 for (i = 0; i < count; i++) {
211 ret = crypto_register_rng(algs + i);
212 if (ret)
213 goto err;
214 }
215
216 return 0;
217
218err:
219 for (--i; i >= 0; --i)
220 crypto_unregister_rng(algs + i);
221
222 return ret;
223}
224EXPORT_SYMBOL_GPL(crypto_register_rngs);
225
226void crypto_unregister_rngs(struct rng_alg *algs, int count)
227{
228 int i;
229
230 for (i = count - 1; i >= 0; --i)
231 crypto_unregister_rng(algs + i);
232}
233EXPORT_SYMBOL_GPL(crypto_unregister_rngs);
234
235MODULE_LICENSE("GPL");
236MODULE_DESCRIPTION("Random Number Generator");