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Commit | Line | Data |
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17f0f4a4 NH |
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 | ||
60063497 | 15 | #include <linux/atomic.h> |
17f0f4a4 NH |
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> | |
5a0e3ad6 | 22 | #include <linux/slab.h> |
17f0f4a4 | 23 | #include <linux/string.h> |
792608e9 SK |
24 | #include <linux/cryptouser.h> |
25 | #include <net/netlink.h> | |
17f0f4a4 NH |
26 | |
27 | static DEFINE_MUTEX(crypto_default_rng_lock); | |
28 | struct crypto_rng *crypto_default_rng; | |
29 | EXPORT_SYMBOL_GPL(crypto_default_rng); | |
30 | static int crypto_default_rng_refcnt; | |
31 | ||
32 | static 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 | ||
52 | static 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 | ||
792608e9 SK |
63 | static 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 | ||
76 | nla_put_failure: | |
77 | return -EMSGSIZE; | |
78 | } | |
79 | ||
17f0f4a4 NH |
80 | static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg) |
81 | __attribute__ ((unused)); | |
82 | static 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 | ||
88 | static unsigned int crypto_rng_ctxsize(struct crypto_alg *alg, u32 type, | |
89 | u32 mask) | |
90 | { | |
91 | return alg->cra_ctxsize; | |
92 | } | |
93 | ||
94 | const 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 | |
792608e9 | 100 | .report = crypto_rng_report, |
17f0f4a4 NH |
101 | }; |
102 | EXPORT_SYMBOL_GPL(crypto_rng_type); | |
103 | ||
104 | int 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 | ||
128 | unlock: | |
129 | mutex_unlock(&crypto_default_rng_lock); | |
130 | ||
131 | return err; | |
132 | } | |
133 | EXPORT_SYMBOL_GPL(crypto_get_default_rng); | |
134 | ||
135 | void 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 | } | |
144 | EXPORT_SYMBOL_GPL(crypto_put_default_rng); | |
145 | ||
146 | MODULE_LICENSE("GPL"); | |
a8ccc393 | 147 | MODULE_DESCRIPTION("Random Number Generator"); |