[thirdparty/kernel/stable.git] / crypto / rng.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Cryptographic API.
 *
 * RNG operations.
 *
 * Copyright (c) 2008 Neil Horman <nhorman@tuxdriver.com>
 * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
 */

#include <linux/atomic.h>
#include <crypto/internal/rng.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/random.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/cryptouser.h>
#include <linux/compiler.h>
#include <net/netlink.h>

#include "internal.h"

static DEFINE_MUTEX(crypto_default_rng_lock);
struct crypto_rng *crypto_default_rng;
EXPORT_SYMBOL_GPL(crypto_default_rng);
static int crypto_default_rng_refcnt;

int crypto_rng_reset(struct crypto_rng *tfm, const u8 *seed, unsigned int slen)
{
	struct crypto_alg *alg = tfm->base.__crt_alg;
	u8 *buf = NULL;
	int err;

	crypto_stats_get(alg);
	if (!seed && slen) {
		buf = kmalloc(slen, GFP_KERNEL);
		if (!buf)
			return -ENOMEM;

		err = get_random_bytes_wait(buf, slen);
		if (err)
			goto out;
		seed = buf;
	}

	err = crypto_rng_alg(tfm)->seed(tfm, seed, slen);
	crypto_stats_rng_seed(alg, err);
out:
	kzfree(buf);
	return err;
}
EXPORT_SYMBOL_GPL(crypto_rng_reset);

static int crypto_rng_init_tfm(struct crypto_tfm *tfm)
{
	return 0;
}

static unsigned int seedsize(struct crypto_alg *alg)
{
	struct rng_alg *ralg = container_of(alg, struct rng_alg, base);

	return ralg->seedsize;
}

#ifdef CONFIG_NET
static int crypto_rng_report(struct sk_buff *skb, struct crypto_alg *alg)
{
	struct crypto_report_rng rrng;

	memset(&rrng, 0, sizeof(rrng));

	strscpy(rrng.type, "rng", sizeof(rrng.type));

	rrng.seedsize = seedsize(alg);

	return nla_put(skb, CRYPTOCFGA_REPORT_RNG, sizeof(rrng), &rrng);
}
#else
static int crypto_rng_report(struct sk_buff *skb, struct crypto_alg *alg)
{
	return -ENOSYS;
}
#endif

static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg)
	__maybe_unused;
static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg)
{
	seq_printf(m, "type         : rng\n");
	seq_printf(m, "seedsize     : %u\n", seedsize(alg));
}

static const struct crypto_type crypto_rng_type = {
	.extsize = crypto_alg_extsize,
	.init_tfm = crypto_rng_init_tfm,
#ifdef CONFIG_PROC_FS
	.show = crypto_rng_show,
#endif
	.report = crypto_rng_report,
	.maskclear = ~CRYPTO_ALG_TYPE_MASK,
	.maskset = CRYPTO_ALG_TYPE_MASK,
	.type = CRYPTO_ALG_TYPE_RNG,
	.tfmsize = offsetof(struct crypto_rng, base),
};

struct crypto_rng *crypto_alloc_rng(const char *alg_name, u32 type, u32 mask)
{
	return crypto_alloc_tfm(alg_name, &crypto_rng_type, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_alloc_rng);

int crypto_get_default_rng(void)
{
	struct crypto_rng *rng;
	int err;

	mutex_lock(&crypto_default_rng_lock);
	if (!crypto_default_rng) {
		rng = crypto_alloc_rng("stdrng", 0, 0);
		err = PTR_ERR(rng);
		if (IS_ERR(rng))
			goto unlock;

		err = crypto_rng_reset(rng, NULL, crypto_rng_seedsize(rng));
		if (err) {
			crypto_free_rng(rng);
			goto unlock;
		}

		crypto_default_rng = rng;
	}

	crypto_default_rng_refcnt++;
	err = 0;

unlock:
	mutex_unlock(&crypto_default_rng_lock);

	return err;
}
EXPORT_SYMBOL_GPL(crypto_get_default_rng);

void crypto_put_default_rng(void)
{
	mutex_lock(&crypto_default_rng_lock);
	crypto_default_rng_refcnt--;
	mutex_unlock(&crypto_default_rng_lock);
}
EXPORT_SYMBOL_GPL(crypto_put_default_rng);

#if defined(CONFIG_CRYPTO_RNG) || defined(CONFIG_CRYPTO_RNG_MODULE)
int crypto_del_default_rng(void)
{
	int err = -EBUSY;

	mutex_lock(&crypto_default_rng_lock);
	if (crypto_default_rng_refcnt)
		goto out;

	crypto_free_rng(crypto_default_rng);
	crypto_default_rng = NULL;

	err = 0;

out:
	mutex_unlock(&crypto_default_rng_lock);

	return err;
}
EXPORT_SYMBOL_GPL(crypto_del_default_rng);
#endif

int crypto_register_rng(struct rng_alg *alg)
{
	struct crypto_alg *base = &alg->base;

	if (alg->seedsize > PAGE_SIZE / 8)
		return -EINVAL;

	base->cra_type = &crypto_rng_type;
	base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
	base->cra_flags |= CRYPTO_ALG_TYPE_RNG;

	return crypto_register_alg(base);
}
EXPORT_SYMBOL_GPL(crypto_register_rng);

void crypto_unregister_rng(struct rng_alg *alg)
{
	crypto_unregister_alg(&alg->base);
}
EXPORT_SYMBOL_GPL(crypto_unregister_rng);

int crypto_register_rngs(struct rng_alg *algs, int count)
{
	int i, ret;

	for (i = 0; i < count; i++) {
		ret = crypto_register_rng(algs + i);
		if (ret)
			goto err;
	}

	return 0;

err:
	for (--i; i >= 0; --i)
		crypto_unregister_rng(algs + i);

	return ret;
}
EXPORT_SYMBOL_GPL(crypto_register_rngs);

void crypto_unregister_rngs(struct rng_alg *algs, int count)
{
	int i;

	for (i = count - 1; i >= 0; --i)
		crypto_unregister_rng(algs + i);
}
EXPORT_SYMBOL_GPL(crypto_unregister_rngs);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Random Number Generator");
Commit	Line	Data
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
17f0f4a4 NH	2	/*
	3	* Cryptographic API.
	4	*
	5	* RNG operations.
	6	*
	7	* Copyright (c) 2008 Neil Horman <nhorman@tuxdriver.com>
94f1bb15	8	* Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
17f0f4a4 NH	9	*/
17f0f4a4 NH	10
60063497	11	#include <linux/atomic.h>
17f0f4a4 NH	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>
5a0e3ad6	18	#include <linux/slab.h>
17f0f4a4	19	#include <linux/string.h>
792608e9	20	#include <linux/cryptouser.h>
d8c34b94	21	#include <linux/compiler.h>
792608e9	22	#include <net/netlink.h>
17f0f4a4	23
d0e83059 HX	24	#include "internal.h"
d0e83059 HX	25
17f0f4a4 NH	26	static DEFINE_MUTEX(crypto_default_rng_lock);
	27	struct crypto_rng *crypto_default_rng;
	28	EXPORT_SYMBOL_GPL(crypto_default_rng);
	29	static int crypto_default_rng_refcnt;
	30
3c5d8fa9	31	int crypto_rng_reset(struct crypto_rng tfm, const u8 seed, unsigned int slen)
17f0f4a4	32	{
f7d76e05	33	struct crypto_alg *alg = tfm->base.__crt_alg;
17f0f4a4 NH	34	u8 *buf = NULL;
	35	int err;
	36
f7d76e05	37	crypto_stats_get(alg);
17f0f4a4 NH	38	if (!seed && slen) {
	39	buf = kmalloc(slen, GFP_KERNEL);
	40	if (!buf)
	41	return -ENOMEM;
	42
c2176f00 JD	43	err = get_random_bytes_wait(buf, slen);
	44	if (err)
	45	goto out;
17f0f4a4 NH	46	seed = buf;
	47	}
	48
94f1bb15	49	err = crypto_rng_alg(tfm)->seed(tfm, seed, slen);
f7d76e05	50	crypto_stats_rng_seed(alg, err);
c2176f00	51	out:
b617b702	52	kzfree(buf);
17f0f4a4 NH	53	return err;
17f0f4a4 NH	54	}
3c5d8fa9	55	EXPORT_SYMBOL_GPL(crypto_rng_reset);
17f0f4a4	56
d0e83059	57	static int crypto_rng_init_tfm(struct crypto_tfm *tfm)
17f0f4a4	58	{
17f0f4a4 NH	59	return 0;
	60	}
	61
acec27ff HX	62	static unsigned int seedsize(struct crypto_alg *alg)
	63	{
	64	struct rng_alg *ralg = container_of(alg, struct rng_alg, base);
	65
94f1bb15	66	return ralg->seedsize;
acec27ff HX	67	}
acec27ff HX	68
3acc8473	69	#ifdef CONFIG_NET
792608e9 SK	70	static int crypto_rng_report(struct sk_buff skb, struct crypto_alg alg)
	71	{
	72	struct crypto_report_rng rrng;
	73
37db69e0	74	memset(&rrng, 0, sizeof(rrng));
792608e9	75
37db69e0	76	strscpy(rrng.type, "rng", sizeof(rrng.type));
792608e9	77
37db69e0	78	rrng.seedsize = seedsize(alg);
792608e9	79
37db69e0	80	return nla_put(skb, CRYPTOCFGA_REPORT_RNG, sizeof(rrng), &rrng);
792608e9	81	}
3acc8473 HX	82	#else
	83	static int crypto_rng_report(struct sk_buff skb, struct crypto_alg alg)
	84	{
	85	return -ENOSYS;
	86	}
	87	#endif
792608e9	88
17f0f4a4	89	static void crypto_rng_show(struct seq_file m, struct crypto_alg alg)
d8c34b94	90	__maybe_unused;
17f0f4a4 NH	91	static void crypto_rng_show(struct seq_file m, struct crypto_alg alg)
	92	{
	93	seq_printf(m, "type : rng\n");
acec27ff	94	seq_printf(m, "seedsize : %u\n", seedsize(alg));
17f0f4a4 NH	95	}
17f0f4a4 NH	96
94f1bb15	97	static const struct crypto_type crypto_rng_type = {
d0e83059 HX	98	.extsize = crypto_alg_extsize,
d0e83059 HX	99	.init_tfm = crypto_rng_init_tfm,
17f0f4a4 NH	100	#ifdef CONFIG_PROC_FS
	101	.show = crypto_rng_show,
	102	#endif
792608e9	103	.report = crypto_rng_report,
d0e83059 HX	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),
17f0f4a4	108	};
17f0f4a4	109
d0e83059 HX	110	struct 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	}
	114	EXPORT_SYMBOL_GPL(crypto_alloc_rng);
	115
17f0f4a4 NH	116	int 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
	140	unlock:
	141	mutex_unlock(&crypto_default_rng_lock);
	142
	143	return err;
	144	}
	145	EXPORT_SYMBOL_GPL(crypto_get_default_rng);
	146
	147	void crypto_put_default_rng(void)
	148	{
	149	mutex_lock(&crypto_default_rng_lock);
7cecadb7	150	crypto_default_rng_refcnt--;
17f0f4a4 NH	151	mutex_unlock(&crypto_default_rng_lock);
	152	}
	153	EXPORT_SYMBOL_GPL(crypto_put_default_rng);
	154
7cecadb7 HX	155	#if defined(CONFIG_CRYPTO_RNG) \|\| defined(CONFIG_CRYPTO_RNG_MODULE)
	156	int 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
	169	out:
	170	mutex_unlock(&crypto_default_rng_lock);
	171
	172	return err;
	173	}
	174	EXPORT_SYMBOL_GPL(crypto_del_default_rng);
	175	#endif
	176
acec27ff HX	177	int 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	}
	190	EXPORT_SYMBOL_GPL(crypto_register_rng);
	191
	192	void crypto_unregister_rng(struct rng_alg *alg)
	193	{
	194	crypto_unregister_alg(&alg->base);
	195	}
	196	EXPORT_SYMBOL_GPL(crypto_unregister_rng);
	197
881cd6c5 HX	198	int 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
	210	err:
	211	for (--i; i >= 0; --i)
	212	crypto_unregister_rng(algs + i);
	213
	214	return ret;
	215	}
	216	EXPORT_SYMBOL_GPL(crypto_register_rngs);
	217
	218	void 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	}
	225	EXPORT_SYMBOL_GPL(crypto_unregister_rngs);
	226
17f0f4a4	227	MODULE_LICENSE("GPL");
a8ccc393	228	MODULE_DESCRIPTION("Random Number Generator");