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 <linux/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#include <linux/cryptouser.h>
 25#include <net/netlink.h>
 26
 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
 63#ifdef CONFIG_NET
 64static int crypto_rng_report(struct sk_buff *skb, struct crypto_alg *alg)
 65{
 66	struct crypto_report_rng rrng;
 67
 68	strncpy(rrng.type, "rng", sizeof(rrng.type));
 69
 70	rrng.seedsize = alg->cra_rng.seedsize;
 71
 72	if (nla_put(skb, CRYPTOCFGA_REPORT_RNG,
 73		    sizeof(struct crypto_report_rng), &rrng))
 74		goto nla_put_failure;
 75	return 0;
 76
 77nla_put_failure:
 78	return -EMSGSIZE;
 79}
 80#else
 81static int crypto_rng_report(struct sk_buff *skb, struct crypto_alg *alg)
 82{
 83	return -ENOSYS;
 84}
 85#endif
 86
 87static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg)
 88	__attribute__ ((unused));
 89static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg)
 90{
 91	seq_printf(m, "type         : rng\n");
 92	seq_printf(m, "seedsize     : %u\n", alg->cra_rng.seedsize);
 93}
 94
 95static unsigned int crypto_rng_ctxsize(struct crypto_alg *alg, u32 type,
 96				       u32 mask)
 97{
 98	return alg->cra_ctxsize;
 99}
100
101const struct crypto_type crypto_rng_type = {
102	.ctxsize = crypto_rng_ctxsize,
103	.init = crypto_init_rng_ops,
104#ifdef CONFIG_PROC_FS
105	.show = crypto_rng_show,
106#endif
107	.report = crypto_rng_report,
108};
109EXPORT_SYMBOL_GPL(crypto_rng_type);
110
111int crypto_get_default_rng(void)
112{
113	struct crypto_rng *rng;
114	int err;
115
116	mutex_lock(&crypto_default_rng_lock);
117	if (!crypto_default_rng) {
118		rng = crypto_alloc_rng("stdrng", 0, 0);
119		err = PTR_ERR(rng);
120		if (IS_ERR(rng))
121			goto unlock;
122
123		err = crypto_rng_reset(rng, NULL, crypto_rng_seedsize(rng));
124		if (err) {
125			crypto_free_rng(rng);
126			goto unlock;
127		}
128
129		crypto_default_rng = rng;
130	}
131
132	crypto_default_rng_refcnt++;
133	err = 0;
134
135unlock:
136	mutex_unlock(&crypto_default_rng_lock);
137
138	return err;
139}
140EXPORT_SYMBOL_GPL(crypto_get_default_rng);
141
142void crypto_put_default_rng(void)
143{
144	mutex_lock(&crypto_default_rng_lock);
145	if (!--crypto_default_rng_refcnt) {
146		crypto_free_rng(crypto_default_rng);
147		crypto_default_rng = NULL;
148	}
149	mutex_unlock(&crypto_default_rng_lock);
150}
151EXPORT_SYMBOL_GPL(crypto_put_default_rng);
152
153MODULE_LICENSE("GPL");
154MODULE_DESCRIPTION("Random Number Generator");

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Cryptographic API.
  4 *
  5 * RNG operations.
  6 *
  7 * Copyright (c) 2008 Neil Horman <nhorman@tuxdriver.com>
  8 * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
  9 */
 10
 11#include <linux/atomic.h>
 12#include <crypto/internal/rng.h>
 13#include <linux/err.h>
 14#include <linux/module.h>
 15#include <linux/mutex.h>
 16#include <linux/random.h>
 17#include <linux/seq_file.h>
 18#include <linux/slab.h>
 19#include <linux/string.h>
 20#include <linux/cryptouser.h>
 21#include <linux/compiler.h>
 22#include <net/netlink.h>
 23
 24#include "internal.h"
 25
 26static DEFINE_MUTEX(crypto_default_rng_lock);
 27struct crypto_rng *crypto_default_rng;
 28EXPORT_SYMBOL_GPL(crypto_default_rng);
 29static int crypto_default_rng_refcnt;
 30
 31int crypto_rng_reset(struct crypto_rng *tfm, const u8 *seed, unsigned int slen)
 32{
 33	struct crypto_alg *alg = tfm->base.__crt_alg;
 34	u8 *buf = NULL;
 35	int err;
 36
 37	crypto_stats_get(alg);
 38	if (!seed && slen) {
 39		buf = kmalloc(slen, GFP_KERNEL);
 40		if (!buf)
 41			return -ENOMEM;
 42
 43		err = get_random_bytes_wait(buf, slen);
 44		if (err)
 45			goto out;
 46		seed = buf;
 47	}
 48
 49	err = crypto_rng_alg(tfm)->seed(tfm, seed, slen);
 50	crypto_stats_rng_seed(alg, err);
 51out:
 52	kzfree(buf);
 53	return err;
 54}
 55EXPORT_SYMBOL_GPL(crypto_rng_reset);
 56
 57static int crypto_rng_init_tfm(struct crypto_tfm *tfm)
 58{
 59	return 0;
 60}
 61
 62static unsigned int seedsize(struct crypto_alg *alg)
 63{
 64	struct rng_alg *ralg = container_of(alg, struct rng_alg, base);
 65
 66	return ralg->seedsize;
 67}
 68
 69#ifdef CONFIG_NET
 70static int crypto_rng_report(struct sk_buff *skb, struct crypto_alg *alg)
 71{
 72	struct crypto_report_rng rrng;
 73
 74	memset(&rrng, 0, sizeof(rrng));
 75
 76	strscpy(rrng.type, "rng", sizeof(rrng.type));
 77
 78	rrng.seedsize = seedsize(alg);
 79
 80	return nla_put(skb, CRYPTOCFGA_REPORT_RNG, sizeof(rrng), &rrng);
 81}
 82#else
 83static int crypto_rng_report(struct sk_buff *skb, struct crypto_alg *alg)
 84{
 85	return -ENOSYS;
 86}
 87#endif
 88
 89static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg)
 90	__maybe_unused;
 91static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg)
 92{
 93	seq_printf(m, "type         : rng\n");
 94	seq_printf(m, "seedsize     : %u\n", seedsize(alg));
 95}
 96
 97static const struct crypto_type crypto_rng_type = {
 98	.extsize = crypto_alg_extsize,
 99	.init_tfm = crypto_rng_init_tfm,
100#ifdef CONFIG_PROC_FS
101	.show = crypto_rng_show,
102#endif
103	.report = crypto_rng_report,
104	.maskclear = ~CRYPTO_ALG_TYPE_MASK,
105	.maskset = CRYPTO_ALG_TYPE_MASK,
106	.type = CRYPTO_ALG_TYPE_RNG,
107	.tfmsize = offsetof(struct crypto_rng, base),
108};
109
110struct crypto_rng *crypto_alloc_rng(const char *alg_name, u32 type, u32 mask)
111{
112	return crypto_alloc_tfm(alg_name, &crypto_rng_type, type, mask);
113}
114EXPORT_SYMBOL_GPL(crypto_alloc_rng);
115
116int crypto_get_default_rng(void)
117{
118	struct crypto_rng *rng;
119	int err;
120
121	mutex_lock(&crypto_default_rng_lock);
122	if (!crypto_default_rng) {
123		rng = crypto_alloc_rng("stdrng", 0, 0);
124		err = PTR_ERR(rng);
125		if (IS_ERR(rng))
126			goto unlock;
127
128		err = crypto_rng_reset(rng, NULL, crypto_rng_seedsize(rng));
129		if (err) {
130			crypto_free_rng(rng);
131			goto unlock;
132		}
133
134		crypto_default_rng = rng;
135	}
136
137	crypto_default_rng_refcnt++;
138	err = 0;
139
140unlock:
141	mutex_unlock(&crypto_default_rng_lock);
142
143	return err;
144}
145EXPORT_SYMBOL_GPL(crypto_get_default_rng);
146
147void crypto_put_default_rng(void)
148{
149	mutex_lock(&crypto_default_rng_lock);
150	crypto_default_rng_refcnt--;
151	mutex_unlock(&crypto_default_rng_lock);
152}
153EXPORT_SYMBOL_GPL(crypto_put_default_rng);
154
155#if defined(CONFIG_CRYPTO_RNG) || defined(CONFIG_CRYPTO_RNG_MODULE)
156int crypto_del_default_rng(void)
157{
158	int err = -EBUSY;
159
160	mutex_lock(&crypto_default_rng_lock);
161	if (crypto_default_rng_refcnt)
162		goto out;
163
164	crypto_free_rng(crypto_default_rng);
165	crypto_default_rng = NULL;
166
167	err = 0;
168
169out:
170	mutex_unlock(&crypto_default_rng_lock);
171
172	return err;
173}
174EXPORT_SYMBOL_GPL(crypto_del_default_rng);
175#endif
176
177int crypto_register_rng(struct rng_alg *alg)
178{
179	struct crypto_alg *base = &alg->base;
180
181	if (alg->seedsize > PAGE_SIZE / 8)
182		return -EINVAL;
183
184	base->cra_type = &crypto_rng_type;
185	base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
186	base->cra_flags |= CRYPTO_ALG_TYPE_RNG;
187
188	return crypto_register_alg(base);
189}
190EXPORT_SYMBOL_GPL(crypto_register_rng);
191
192void crypto_unregister_rng(struct rng_alg *alg)
193{
194	crypto_unregister_alg(&alg->base);
195}
196EXPORT_SYMBOL_GPL(crypto_unregister_rng);
197
198int crypto_register_rngs(struct rng_alg *algs, int count)
199{
200	int i, ret;
201
202	for (i = 0; i < count; i++) {
203		ret = crypto_register_rng(algs + i);
204		if (ret)
205			goto err;
206	}
207
208	return 0;
209
210err:
211	for (--i; i >= 0; --i)
212		crypto_unregister_rng(algs + i);
213
214	return ret;
215}
216EXPORT_SYMBOL_GPL(crypto_register_rngs);
217
218void crypto_unregister_rngs(struct rng_alg *algs, int count)
219{
220	int i;
221
222	for (i = count - 1; i >= 0; --i)
223		crypto_unregister_rng(algs + i);
224}
225EXPORT_SYMBOL_GPL(crypto_unregister_rngs);
226
227MODULE_LICENSE("GPL");
228MODULE_DESCRIPTION("Random Number Generator");