[mirror_ubuntu-artful-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;

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