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Neil Horman17f0f4a2008-08-14 22:15:52 +10001/*
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
Arun Sharma600634972011-07-26 16:09:06 -070015#include <linux/atomic.h>
Neil Horman17f0f4a2008-08-14 22:15:52 +100016#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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090022#include <linux/slab.h>
Neil Horman17f0f4a2008-08-14 22:15:52 +100023#include <linux/string.h>
Steffen Klassert792608e2011-09-27 07:47:11 +020024#include <linux/cryptouser.h>
25#include <net/netlink.h>
Neil Horman17f0f4a2008-08-14 22:15:52 +100026
27static DEFINE_MUTEX(crypto_default_rng_lock);
28struct crypto_rng *crypto_default_rng;
29EXPORT_SYMBOL_GPL(crypto_default_rng);
30static int crypto_default_rng_refcnt;
31
32static int rngapi_reset(struct crypto_rng *tfm, u8 *seed, unsigned int slen)
33{
34 u8 *buf = NULL;
35 int err;
36
37 if (!seed && slen) {
38 buf = kmalloc(slen, GFP_KERNEL);
39 if (!buf)
40 return -ENOMEM;
41
42 get_random_bytes(buf, slen);
43 seed = buf;
44 }
45
46 err = crypto_rng_alg(tfm)->rng_reset(tfm, seed, slen);
47
48 kfree(buf);
49 return err;
50}
51
52static int crypto_init_rng_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
53{
54 struct rng_alg *alg = &tfm->__crt_alg->cra_rng;
55 struct rng_tfm *ops = &tfm->crt_rng;
56
57 ops->rng_gen_random = alg->rng_make_random;
58 ops->rng_reset = rngapi_reset;
59
60 return 0;
61}
62
Steffen Klassert792608e2011-09-27 07:47:11 +020063static int crypto_rng_report(struct sk_buff *skb, struct crypto_alg *alg)
64{
65 struct crypto_report_rng rrng;
66
67 snprintf(rrng.type, CRYPTO_MAX_ALG_NAME, "%s", "rng");
68
69 rrng.seedsize = alg->cra_rng.seedsize;
70
71 NLA_PUT(skb, CRYPTOCFGA_REPORT_RNG,
72 sizeof(struct crypto_report_rng), &rrng);
73
74 return 0;
75
76nla_put_failure:
77 return -EMSGSIZE;
78}
79
Neil Horman17f0f4a2008-08-14 22:15:52 +100080static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg)
81 __attribute__ ((unused));
82static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg)
83{
84 seq_printf(m, "type : rng\n");
85 seq_printf(m, "seedsize : %u\n", alg->cra_rng.seedsize);
86}
87
88static unsigned int crypto_rng_ctxsize(struct crypto_alg *alg, u32 type,
89 u32 mask)
90{
91 return alg->cra_ctxsize;
92}
93
94const struct crypto_type crypto_rng_type = {
95 .ctxsize = crypto_rng_ctxsize,
96 .init = crypto_init_rng_ops,
97#ifdef CONFIG_PROC_FS
98 .show = crypto_rng_show,
99#endif
Steffen Klassert792608e2011-09-27 07:47:11 +0200100 .report = crypto_rng_report,
Neil Horman17f0f4a2008-08-14 22:15:52 +1000101};
102EXPORT_SYMBOL_GPL(crypto_rng_type);
103
104int crypto_get_default_rng(void)
105{
106 struct crypto_rng *rng;
107 int err;
108
109 mutex_lock(&crypto_default_rng_lock);
110 if (!crypto_default_rng) {
111 rng = crypto_alloc_rng("stdrng", 0, 0);
112 err = PTR_ERR(rng);
113 if (IS_ERR(rng))
114 goto unlock;
115
116 err = crypto_rng_reset(rng, NULL, crypto_rng_seedsize(rng));
117 if (err) {
118 crypto_free_rng(rng);
119 goto unlock;
120 }
121
122 crypto_default_rng = rng;
123 }
124
125 crypto_default_rng_refcnt++;
126 err = 0;
127
128unlock:
129 mutex_unlock(&crypto_default_rng_lock);
130
131 return err;
132}
133EXPORT_SYMBOL_GPL(crypto_get_default_rng);
134
135void crypto_put_default_rng(void)
136{
137 mutex_lock(&crypto_default_rng_lock);
138 if (!--crypto_default_rng_refcnt) {
139 crypto_free_rng(crypto_default_rng);
140 crypto_default_rng = NULL;
141 }
142 mutex_unlock(&crypto_default_rng_lock);
143}
144EXPORT_SYMBOL_GPL(crypto_put_default_rng);
145
146MODULE_LICENSE("GPL");
Christian Kujaua8ccc392009-08-13 11:53:56 +1000147MODULE_DESCRIPTION("Random Number Generator");