[linux-2.6-block.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;

static inline struct crypto_rng *__crypto_rng_cast(struct crypto_tfm *tfm)
{
	return container_of(tfm, struct crypto_rng, base);
}

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;

		get_random_bytes(buf, slen);
		seed = buf;
	}

	err = crypto_rng_alg(tfm)->seed(tfm, seed, slen);

	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
d0e83059 HX	36	static inline struct crypto_rng __crypto_rng_cast(struct crypto_tfm tfm)
	37	{
	38	return container_of(tfm, struct crypto_rng, base);
	39	}
	40
3c5d8fa9	41	int crypto_rng_reset(struct crypto_rng tfm, const u8 seed, unsigned int slen)
17f0f4a4 NH	42	{
	43	u8 *buf = NULL;
	44	int err;
	45
	46	if (!seed && slen) {
	47	buf = kmalloc(slen, GFP_KERNEL);
	48	if (!buf)
	49	return -ENOMEM;
	50
	51	get_random_bytes(buf, slen);
	52	seed = buf;
	53	}
	54
94f1bb15	55	err = crypto_rng_alg(tfm)->seed(tfm, seed, slen);
17f0f4a4	56
b617b702	57	kzfree(buf);
17f0f4a4 NH	58	return err;
17f0f4a4 NH	59	}
3c5d8fa9	60	EXPORT_SYMBOL_GPL(crypto_rng_reset);
17f0f4a4	61
d0e83059	62	static int crypto_rng_init_tfm(struct crypto_tfm *tfm)
17f0f4a4	63	{
17f0f4a4 NH	64	return 0;
	65	}
	66
acec27ff HX	67	static unsigned int seedsize(struct crypto_alg *alg)
	68	{
	69	struct rng_alg *ralg = container_of(alg, struct rng_alg, base);
	70
94f1bb15	71	return ralg->seedsize;
acec27ff HX	72	}
acec27ff HX	73
3acc8473	74	#ifdef CONFIG_NET
792608e9 SK	75	static int crypto_rng_report(struct sk_buff skb, struct crypto_alg alg)
	76	{
	77	struct crypto_report_rng rrng;
	78
9a5467bf	79	strncpy(rrng.type, "rng", sizeof(rrng.type));
792608e9	80
acec27ff	81	rrng.seedsize = seedsize(alg);
792608e9	82
6662df33 DM	83	if (nla_put(skb, CRYPTOCFGA_REPORT_RNG,
	84	sizeof(struct crypto_report_rng), &rrng))
	85	goto nla_put_failure;
792608e9 SK	86	return 0;
	87
	88	nla_put_failure:
	89	return -EMSGSIZE;
	90	}
3acc8473 HX	91	#else
	92	static int crypto_rng_report(struct sk_buff skb, struct crypto_alg alg)
	93	{
	94	return -ENOSYS;
	95	}
	96	#endif
792608e9	97
17f0f4a4	98	static void crypto_rng_show(struct seq_file m, struct crypto_alg alg)
d8c34b94	99	__maybe_unused;
17f0f4a4 NH	100	static void crypto_rng_show(struct seq_file m, struct crypto_alg alg)
	101	{
	102	seq_printf(m, "type : rng\n");
acec27ff	103	seq_printf(m, "seedsize : %u\n", seedsize(alg));
17f0f4a4 NH	104	}
17f0f4a4 NH	105
94f1bb15	106	static const struct crypto_type crypto_rng_type = {
d0e83059 HX	107	.extsize = crypto_alg_extsize,
d0e83059 HX	108	.init_tfm = crypto_rng_init_tfm,
17f0f4a4 NH	109	#ifdef CONFIG_PROC_FS
	110	.show = crypto_rng_show,
	111	#endif
792608e9	112	.report = crypto_rng_report,
d0e83059 HX	113	.maskclear = ~CRYPTO_ALG_TYPE_MASK,
	114	.maskset = CRYPTO_ALG_TYPE_MASK,
	115	.type = CRYPTO_ALG_TYPE_RNG,
	116	.tfmsize = offsetof(struct crypto_rng, base),
17f0f4a4	117	};
17f0f4a4	118
d0e83059 HX	119	struct crypto_rng crypto_alloc_rng(const char alg_name, u32 type, u32 mask)
	120	{
	121	return crypto_alloc_tfm(alg_name, &crypto_rng_type, type, mask);
	122	}
	123	EXPORT_SYMBOL_GPL(crypto_alloc_rng);
	124
17f0f4a4 NH	125	int crypto_get_default_rng(void)
	126	{
	127	struct crypto_rng *rng;
	128	int err;
	129
	130	mutex_lock(&crypto_default_rng_lock);
	131	if (!crypto_default_rng) {
	132	rng = crypto_alloc_rng("stdrng", 0, 0);
	133	err = PTR_ERR(rng);
	134	if (IS_ERR(rng))
	135	goto unlock;
	136
	137	err = crypto_rng_reset(rng, NULL, crypto_rng_seedsize(rng));
	138	if (err) {
	139	crypto_free_rng(rng);
	140	goto unlock;
	141	}
	142
	143	crypto_default_rng = rng;
	144	}
	145
	146	crypto_default_rng_refcnt++;
	147	err = 0;
	148
	149	unlock:
	150	mutex_unlock(&crypto_default_rng_lock);
	151
	152	return err;
	153	}
	154	EXPORT_SYMBOL_GPL(crypto_get_default_rng);
	155
	156	void crypto_put_default_rng(void)
	157	{
	158	mutex_lock(&crypto_default_rng_lock);
7cecadb7	159	crypto_default_rng_refcnt--;
17f0f4a4 NH	160	mutex_unlock(&crypto_default_rng_lock);
	161	}
	162	EXPORT_SYMBOL_GPL(crypto_put_default_rng);
	163
7cecadb7 HX	164	#if defined(CONFIG_CRYPTO_RNG) \|\| defined(CONFIG_CRYPTO_RNG_MODULE)
	165	int crypto_del_default_rng(void)
	166	{
	167	int err = -EBUSY;
	168
	169	mutex_lock(&crypto_default_rng_lock);
	170	if (crypto_default_rng_refcnt)
	171	goto out;
	172
	173	crypto_free_rng(crypto_default_rng);
	174	crypto_default_rng = NULL;
	175
	176	err = 0;
	177
	178	out:
	179	mutex_unlock(&crypto_default_rng_lock);
	180
	181	return err;
	182	}
	183	EXPORT_SYMBOL_GPL(crypto_del_default_rng);
	184	#endif
	185
acec27ff HX	186	int crypto_register_rng(struct rng_alg *alg)
	187	{
	188	struct crypto_alg *base = &alg->base;
	189
	190	if (alg->seedsize > PAGE_SIZE / 8)
	191	return -EINVAL;
	192
	193	base->cra_type = &crypto_rng_type;
	194	base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
	195	base->cra_flags \|= CRYPTO_ALG_TYPE_RNG;
	196
	197	return crypto_register_alg(base);
	198	}
	199	EXPORT_SYMBOL_GPL(crypto_register_rng);
	200
	201	void crypto_unregister_rng(struct rng_alg *alg)
	202	{
	203	crypto_unregister_alg(&alg->base);
	204	}
	205	EXPORT_SYMBOL_GPL(crypto_unregister_rng);
	206
881cd6c5 HX	207	int crypto_register_rngs(struct rng_alg *algs, int count)
	208	{
	209	int i, ret;
	210
	211	for (i = 0; i < count; i++) {
	212	ret = crypto_register_rng(algs + i);
	213	if (ret)
	214	goto err;
	215	}
	216
	217	return 0;
	218
	219	err:
	220	for (--i; i >= 0; --i)
	221	crypto_unregister_rng(algs + i);
	222
	223	return ret;
	224	}
	225	EXPORT_SYMBOL_GPL(crypto_register_rngs);
	226
	227	void crypto_unregister_rngs(struct rng_alg *algs, int count)
	228	{
	229	int i;
	230
	231	for (i = count - 1; i >= 0; --i)
	232	crypto_unregister_rng(algs + i);
	233	}
	234	EXPORT_SYMBOL_GPL(crypto_unregister_rngs);
	235
17f0f4a4	236	MODULE_LICENSE("GPL");
a8ccc393	237	MODULE_DESCRIPTION("Random Number Generator");