Root/crypto/rng.c

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/slab.h>
23#include <linux/string.h>
24
25static DEFINE_MUTEX(crypto_default_rng_lock);
26struct crypto_rng *crypto_default_rng;
27EXPORT_SYMBOL_GPL(crypto_default_rng);
28static int crypto_default_rng_refcnt;
29
30static int rngapi_reset(struct crypto_rng *tfm, u8 *seed, unsigned int slen)
31{
32    u8 *buf = NULL;
33    int err;
34
35    if (!seed && slen) {
36        buf = kmalloc(slen, GFP_KERNEL);
37        if (!buf)
38            return -ENOMEM;
39
40        get_random_bytes(buf, slen);
41        seed = buf;
42    }
43
44    err = crypto_rng_alg(tfm)->rng_reset(tfm, seed, slen);
45
46    kfree(buf);
47    return err;
48}
49
50static int crypto_init_rng_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
51{
52    struct rng_alg *alg = &tfm->__crt_alg->cra_rng;
53    struct rng_tfm *ops = &tfm->crt_rng;
54
55    ops->rng_gen_random = alg->rng_make_random;
56    ops->rng_reset = rngapi_reset;
57
58    return 0;
59}
60
61static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg)
62    __attribute__ ((unused));
63static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg)
64{
65    seq_printf(m, "type : rng\n");
66    seq_printf(m, "seedsize : %u\n", alg->cra_rng.seedsize);
67}
68
69static unsigned int crypto_rng_ctxsize(struct crypto_alg *alg, u32 type,
70                       u32 mask)
71{
72    return alg->cra_ctxsize;
73}
74
75const struct crypto_type crypto_rng_type = {
76    .ctxsize = crypto_rng_ctxsize,
77    .init = crypto_init_rng_ops,
78#ifdef CONFIG_PROC_FS
79    .show = crypto_rng_show,
80#endif
81};
82EXPORT_SYMBOL_GPL(crypto_rng_type);
83
84int crypto_get_default_rng(void)
85{
86    struct crypto_rng *rng;
87    int err;
88
89    mutex_lock(&crypto_default_rng_lock);
90    if (!crypto_default_rng) {
91        rng = crypto_alloc_rng("stdrng", 0, 0);
92        err = PTR_ERR(rng);
93        if (IS_ERR(rng))
94            goto unlock;
95
96        err = crypto_rng_reset(rng, NULL, crypto_rng_seedsize(rng));
97        if (err) {
98            crypto_free_rng(rng);
99            goto unlock;
100        }
101
102        crypto_default_rng = rng;
103    }
104
105    crypto_default_rng_refcnt++;
106    err = 0;
107
108unlock:
109    mutex_unlock(&crypto_default_rng_lock);
110
111    return err;
112}
113EXPORT_SYMBOL_GPL(crypto_get_default_rng);
114
115void crypto_put_default_rng(void)
116{
117    mutex_lock(&crypto_default_rng_lock);
118    if (!--crypto_default_rng_refcnt) {
119        crypto_free_rng(crypto_default_rng);
120        crypto_default_rng = NULL;
121    }
122    mutex_unlock(&crypto_default_rng_lock);
123}
124EXPORT_SYMBOL_GPL(crypto_put_default_rng);
125
126MODULE_LICENSE("GPL");
127MODULE_DESCRIPTION("Random Number Generator");
128

Archive Download this file

Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master

Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9



interactive