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 *
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License as published by the Free
10 * Software Foundation; either version 2 of the License, or (at your option)
11 * any later version.
12 *
13 */
14
15#include <asm/atomic.h>
16#include <crypto/internal/rng.h>
17#include <linux/err.h>
18#include <linux/module.h>
19#include <linux/mutex.h>
20#include <linux/random.h>
21#include <linux/seq_file.h>
22#include <linux/string.h>
23
24static DEFINE_MUTEX(crypto_default_rng_lock);
25struct crypto_rng *crypto_default_rng;
26EXPORT_SYMBOL_GPL(crypto_default_rng);
27static int crypto_default_rng_refcnt;
28
29static int rngapi_reset(struct crypto_rng *tfm, u8 *seed, unsigned int slen)
30{
31 u8 *buf = NULL;
32 int err;
33
34 if (!seed && slen) {
35 buf = kmalloc(slen, GFP_KERNEL);
36 if (!buf)
37 return -ENOMEM;
38
39 get_random_bytes(buf, slen);
40 seed = buf;
41 }
42
43 err = crypto_rng_alg(tfm)->rng_reset(tfm, seed, slen);
44
45 kfree(buf);
46 return err;
47}
48
49static int crypto_init_rng_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
50{
51 struct rng_alg *alg = &tfm->__crt_alg->cra_rng;
52 struct rng_tfm *ops = &tfm->crt_rng;
53
54 ops->rng_gen_random = alg->rng_make_random;
55 ops->rng_reset = rngapi_reset;
56
57 return 0;
58}
59
60static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg)
61 __attribute__ ((unused));
62static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg)
63{
64 seq_printf(m, "type : rng\n");
65 seq_printf(m, "seedsize : %u\n", alg->cra_rng.seedsize);
66}
67
68static unsigned int crypto_rng_ctxsize(struct crypto_alg *alg, u32 type,
69 u32 mask)
70{
71 return alg->cra_ctxsize;
72}
73
74const struct crypto_type crypto_rng_type = {
75 .ctxsize = crypto_rng_ctxsize,
76 .init = crypto_init_rng_ops,
77#ifdef CONFIG_PROC_FS
78 .show = crypto_rng_show,
79#endif
80};
81EXPORT_SYMBOL_GPL(crypto_rng_type);
82
83int crypto_get_default_rng(void)
84{
85 struct crypto_rng *rng;
86 int err;
87
88 mutex_lock(&crypto_default_rng_lock);
89 if (!crypto_default_rng) {
90 rng = crypto_alloc_rng("stdrng", 0, 0);
91 err = PTR_ERR(rng);
92 if (IS_ERR(rng))
93 goto unlock;
94
95 err = crypto_rng_reset(rng, NULL, crypto_rng_seedsize(rng));
96 if (err) {
97 crypto_free_rng(rng);
98 goto unlock;
99 }
100
101 crypto_default_rng = rng;
102 }
103
104 crypto_default_rng_refcnt++;
105 err = 0;
106
107unlock:
108 mutex_unlock(&crypto_default_rng_lock);
109
110 return err;
111}
112EXPORT_SYMBOL_GPL(crypto_get_default_rng);
113
114void crypto_put_default_rng(void)
115{
116 mutex_lock(&crypto_default_rng_lock);
117 if (!--crypto_default_rng_refcnt) {
118 crypto_free_rng(crypto_default_rng);
119 crypto_default_rng = NULL;
120 }
121 mutex_unlock(&crypto_default_rng_lock);
122}
123EXPORT_SYMBOL_GPL(crypto_put_default_rng);
124
125MODULE_LICENSE("GPL");
126MODULE_DESCRIPTION("Random Number Genertor");