Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 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 | |
Arun Sharma | 6006349 | 2011-07-26 16:09:06 -0700 | [diff] [blame] | 15 | #include <linux/atomic.h> |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 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> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 22 | #include <linux/slab.h> |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 23 | #include <linux/string.h> |
Steffen Klassert | 792608e | 2011-09-27 07:47:11 +0200 | [diff] [blame^] | 24 | #include <linux/cryptouser.h> |
| 25 | #include <net/netlink.h> |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 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 | |
Steffen Klassert | 792608e | 2011-09-27 07:47:11 +0200 | [diff] [blame^] | 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 | |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 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 |
Steffen Klassert | 792608e | 2011-09-27 07:47:11 +0200 | [diff] [blame^] | 100 | .report = crypto_rng_report, |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 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"); |
Christian Kujau | a8ccc39 | 2009-08-13 11:53:56 +1000 | [diff] [blame] | 147 | MODULE_DESCRIPTION("Random Number Generator"); |