[linux-2.6-block.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 <crypto/internal/rng.h>
#include <linux/atomic.h>
#include <linux/cryptouser.h>
#include <linux/err.h>
#include <linux/kernel.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 <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)
{
	u8 *buf = NULL;
	int err;

	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);
out:
	kfree_sensitive(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;
}

static int __maybe_unused 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);
}

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