[mirror_ubuntu-bionic-kernel.git] / crypto / rng.c

/*
 * Cryptographic API.
 *
 * RNG operations.
 *
 * Copyright (c) 2008 Neil Horman <nhorman@tuxdriver.com>
 * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 */

#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)
{
	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:
	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;

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

	rrng.seedsize = seedsize(alg);

	if (nla_put(skb, CRYPTOCFGA_REPORT_RNG,
		    sizeof(struct crypto_report_rng), &rrng))
		goto nla_put_failure;
	return 0;

nla_put_failure:
	return -EMSGSIZE;
}
#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
17f0f4a4 NH	1	/*
	2	* Cryptographic API.
	3	*
	4	* RNG operations.
	5	*
	6	* Copyright (c) 2008 Neil Horman <nhorman@tuxdriver.com>
94f1bb15	7	* Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
17f0f4a4 NH	8	*
	9	* This program is free software; you can redistribute it and/or modify it
	10	* under the terms of the GNU General Public License as published by the Free
	11	* Software Foundation; either version 2 of the License, or (at your option)
	12	* any later version.
	13	*
	14	*/
	15
60063497	16	#include <linux/atomic.h>
17f0f4a4 NH	17	#include <crypto/internal/rng.h>
	18	#include <linux/err.h>
	19	#include <linux/module.h>
	20	#include <linux/mutex.h>
	21	#include <linux/random.h>
	22	#include <linux/seq_file.h>
5a0e3ad6	23	#include <linux/slab.h>
17f0f4a4	24	#include <linux/string.h>
792608e9	25	#include <linux/cryptouser.h>
d8c34b94	26	#include <linux/compiler.h>
792608e9	27	#include <net/netlink.h>
17f0f4a4	28
d0e83059 HX	29	#include "internal.h"
d0e83059 HX	30
17f0f4a4 NH	31	static DEFINE_MUTEX(crypto_default_rng_lock);
	32	struct crypto_rng *crypto_default_rng;
	33	EXPORT_SYMBOL_GPL(crypto_default_rng);
	34	static int crypto_default_rng_refcnt;
	35
3c5d8fa9	36	int crypto_rng_reset(struct crypto_rng tfm, const u8 seed, unsigned int slen)
17f0f4a4 NH	37	{
	38	u8 *buf = NULL;
	39	int err;
	40
	41	if (!seed && slen) {
	42	buf = kmalloc(slen, GFP_KERNEL);
	43	if (!buf)
	44	return -ENOMEM;
	45
c2176f00 JD	46	err = get_random_bytes_wait(buf, slen);
	47	if (err)
	48	goto out;
17f0f4a4 NH	49	seed = buf;
	50	}
	51
94f1bb15	52	err = crypto_rng_alg(tfm)->seed(tfm, seed, slen);
c2176f00	53	out:
b617b702	54	kzfree(buf);
17f0f4a4 NH	55	return err;
17f0f4a4 NH	56	}
3c5d8fa9	57	EXPORT_SYMBOL_GPL(crypto_rng_reset);
17f0f4a4	58
d0e83059	59	static int crypto_rng_init_tfm(struct crypto_tfm *tfm)
17f0f4a4	60	{
17f0f4a4 NH	61	return 0;
	62	}
	63
acec27ff HX	64	static unsigned int seedsize(struct crypto_alg *alg)
	65	{
	66	struct rng_alg *ralg = container_of(alg, struct rng_alg, base);
	67
94f1bb15	68	return ralg->seedsize;
acec27ff HX	69	}
acec27ff HX	70
3acc8473	71	#ifdef CONFIG_NET
792608e9 SK	72	static int crypto_rng_report(struct sk_buff skb, struct crypto_alg alg)
	73	{
	74	struct crypto_report_rng rrng;
	75
9a5467bf	76	strncpy(rrng.type, "rng", sizeof(rrng.type));
792608e9	77
acec27ff	78	rrng.seedsize = seedsize(alg);
792608e9	79
6662df33 DM	80	if (nla_put(skb, CRYPTOCFGA_REPORT_RNG,
	81	sizeof(struct crypto_report_rng), &rrng))
	82	goto nla_put_failure;
792608e9 SK	83	return 0;
	84
	85	nla_put_failure:
	86	return -EMSGSIZE;
	87	}
3acc8473 HX	88	#else
	89	static int crypto_rng_report(struct sk_buff skb, struct crypto_alg alg)
	90	{
	91	return -ENOSYS;
	92	}
	93	#endif
792608e9	94
17f0f4a4	95	static void crypto_rng_show(struct seq_file m, struct crypto_alg alg)
d8c34b94	96	__maybe_unused;
17f0f4a4 NH	97	static void crypto_rng_show(struct seq_file m, struct crypto_alg alg)
	98	{
	99	seq_printf(m, "type : rng\n");
acec27ff	100	seq_printf(m, "seedsize : %u\n", seedsize(alg));
17f0f4a4 NH	101	}
17f0f4a4 NH	102
94f1bb15	103	static const struct crypto_type crypto_rng_type = {
d0e83059 HX	104	.extsize = crypto_alg_extsize,
d0e83059 HX	105	.init_tfm = crypto_rng_init_tfm,
17f0f4a4 NH	106	#ifdef CONFIG_PROC_FS
	107	.show = crypto_rng_show,
	108	#endif
792608e9	109	.report = crypto_rng_report,
d0e83059 HX	110	.maskclear = ~CRYPTO_ALG_TYPE_MASK,
	111	.maskset = CRYPTO_ALG_TYPE_MASK,
	112	.type = CRYPTO_ALG_TYPE_RNG,
	113	.tfmsize = offsetof(struct crypto_rng, base),
17f0f4a4	114	};
17f0f4a4	115
d0e83059 HX	116	struct crypto_rng crypto_alloc_rng(const char alg_name, u32 type, u32 mask)
	117	{
	118	return crypto_alloc_tfm(alg_name, &crypto_rng_type, type, mask);
	119	}
	120	EXPORT_SYMBOL_GPL(crypto_alloc_rng);
	121
17f0f4a4 NH	122	int crypto_get_default_rng(void)
	123	{
	124	struct crypto_rng *rng;
	125	int err;
	126
	127	mutex_lock(&crypto_default_rng_lock);
	128	if (!crypto_default_rng) {
	129	rng = crypto_alloc_rng("stdrng", 0, 0);
	130	err = PTR_ERR(rng);
	131	if (IS_ERR(rng))
	132	goto unlock;
	133
	134	err = crypto_rng_reset(rng, NULL, crypto_rng_seedsize(rng));
	135	if (err) {
	136	crypto_free_rng(rng);
	137	goto unlock;
	138	}
	139
	140	crypto_default_rng = rng;
	141	}
	142
	143	crypto_default_rng_refcnt++;
	144	err = 0;
	145
	146	unlock:
	147	mutex_unlock(&crypto_default_rng_lock);
	148
	149	return err;
	150	}
	151	EXPORT_SYMBOL_GPL(crypto_get_default_rng);
	152
	153	void crypto_put_default_rng(void)
	154	{
	155	mutex_lock(&crypto_default_rng_lock);
7cecadb7	156	crypto_default_rng_refcnt--;
17f0f4a4 NH	157	mutex_unlock(&crypto_default_rng_lock);
	158	}
	159	EXPORT_SYMBOL_GPL(crypto_put_default_rng);
	160
7cecadb7 HX	161	#if defined(CONFIG_CRYPTO_RNG) \|\| defined(CONFIG_CRYPTO_RNG_MODULE)
	162	int crypto_del_default_rng(void)
	163	{
	164	int err = -EBUSY;
	165
	166	mutex_lock(&crypto_default_rng_lock);
	167	if (crypto_default_rng_refcnt)
	168	goto out;
	169
	170	crypto_free_rng(crypto_default_rng);
	171	crypto_default_rng = NULL;
	172
	173	err = 0;
	174
	175	out:
	176	mutex_unlock(&crypto_default_rng_lock);
	177
	178	return err;
	179	}
	180	EXPORT_SYMBOL_GPL(crypto_del_default_rng);
	181	#endif
	182
acec27ff HX	183	int crypto_register_rng(struct rng_alg *alg)
	184	{
	185	struct crypto_alg *base = &alg->base;
	186
	187	if (alg->seedsize > PAGE_SIZE / 8)
	188	return -EINVAL;
	189
	190	base->cra_type = &crypto_rng_type;
	191	base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
	192	base->cra_flags \|= CRYPTO_ALG_TYPE_RNG;
	193
	194	return crypto_register_alg(base);
	195	}
	196	EXPORT_SYMBOL_GPL(crypto_register_rng);
	197
	198	void crypto_unregister_rng(struct rng_alg *alg)
	199	{
	200	crypto_unregister_alg(&alg->base);
	201	}
	202	EXPORT_SYMBOL_GPL(crypto_unregister_rng);
	203
881cd6c5 HX	204	int crypto_register_rngs(struct rng_alg *algs, int count)
	205	{
	206	int i, ret;
	207
	208	for (i = 0; i < count; i++) {
	209	ret = crypto_register_rng(algs + i);
	210	if (ret)
	211	goto err;
	212	}
	213
	214	return 0;
	215
	216	err:
	217	for (--i; i >= 0; --i)
	218	crypto_unregister_rng(algs + i);
	219
	220	return ret;
	221	}
	222	EXPORT_SYMBOL_GPL(crypto_register_rngs);
	223
	224	void crypto_unregister_rngs(struct rng_alg *algs, int count)
	225	{
	226	int i;
	227
	228	for (i = count - 1; i >= 0; --i)
	229	crypto_unregister_rng(algs + i);
	230	}
	231	EXPORT_SYMBOL_GPL(crypto_unregister_rngs);
	232
17f0f4a4	233	MODULE_LICENSE("GPL");
a8ccc393	234	MODULE_DESCRIPTION("Random Number Generator");