[mirror_ubuntu-zesty-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 <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)
	__attribute__ ((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 SK	25	#include <linux/cryptouser.h>
792608e9 SK	26	#include <net/netlink.h>
17f0f4a4	27
d0e83059 HX	28	#include "internal.h"
d0e83059 HX	29
17f0f4a4 NH	30	static DEFINE_MUTEX(crypto_default_rng_lock);
	31	struct crypto_rng *crypto_default_rng;
	32	EXPORT_SYMBOL_GPL(crypto_default_rng);
	33	static int crypto_default_rng_refcnt;
	34
d0e83059 HX	35	static inline struct crypto_rng __crypto_rng_cast(struct crypto_tfm tfm)
	36	{
	37	return container_of(tfm, struct crypto_rng, base);
	38	}
	39
3c5d8fa9	40	int crypto_rng_reset(struct crypto_rng tfm, const u8 seed, unsigned int slen)
17f0f4a4 NH	41	{
	42	u8 *buf = NULL;
	43	int err;
	44
	45	if (!seed && slen) {
	46	buf = kmalloc(slen, GFP_KERNEL);
	47	if (!buf)
	48	return -ENOMEM;
	49
	50	get_random_bytes(buf, slen);
	51	seed = buf;
	52	}
	53
94f1bb15	54	err = crypto_rng_alg(tfm)->seed(tfm, seed, slen);
17f0f4a4	55
b617b702	56	kzfree(buf);
17f0f4a4 NH	57	return err;
17f0f4a4 NH	58	}
3c5d8fa9	59	EXPORT_SYMBOL_GPL(crypto_rng_reset);
17f0f4a4	60
d0e83059	61	static int crypto_rng_init_tfm(struct crypto_tfm *tfm)
17f0f4a4	62	{
17f0f4a4 NH	63	return 0;
	64	}
	65
acec27ff HX	66	static unsigned int seedsize(struct crypto_alg *alg)
	67	{
	68	struct rng_alg *ralg = container_of(alg, struct rng_alg, base);
	69
94f1bb15	70	return ralg->seedsize;
acec27ff HX	71	}
acec27ff HX	72
3acc8473	73	#ifdef CONFIG_NET
792608e9 SK	74	static int crypto_rng_report(struct sk_buff skb, struct crypto_alg alg)
	75	{
	76	struct crypto_report_rng rrng;
	77
9a5467bf	78	strncpy(rrng.type, "rng", sizeof(rrng.type));
792608e9	79
acec27ff	80	rrng.seedsize = seedsize(alg);
792608e9	81
6662df33 DM	82	if (nla_put(skb, CRYPTOCFGA_REPORT_RNG,
	83	sizeof(struct crypto_report_rng), &rrng))
	84	goto nla_put_failure;
792608e9 SK	85	return 0;
	86
	87	nla_put_failure:
	88	return -EMSGSIZE;
	89	}
3acc8473 HX	90	#else
	91	static int crypto_rng_report(struct sk_buff skb, struct crypto_alg alg)
	92	{
	93	return -ENOSYS;
	94	}
	95	#endif
792608e9	96
17f0f4a4 NH	97	static void crypto_rng_show(struct seq_file m, struct crypto_alg alg)
	98	__attribute__ ((unused));
	99	static void crypto_rng_show(struct seq_file m, struct crypto_alg alg)
	100	{
	101	seq_printf(m, "type : rng\n");
acec27ff	102	seq_printf(m, "seedsize : %u\n", seedsize(alg));
17f0f4a4 NH	103	}
17f0f4a4 NH	104
94f1bb15	105	static const struct crypto_type crypto_rng_type = {
d0e83059 HX	106	.extsize = crypto_alg_extsize,
d0e83059 HX	107	.init_tfm = crypto_rng_init_tfm,
17f0f4a4 NH	108	#ifdef CONFIG_PROC_FS
	109	.show = crypto_rng_show,
	110	#endif
792608e9	111	.report = crypto_rng_report,
d0e83059 HX	112	.maskclear = ~CRYPTO_ALG_TYPE_MASK,
	113	.maskset = CRYPTO_ALG_TYPE_MASK,
	114	.type = CRYPTO_ALG_TYPE_RNG,
	115	.tfmsize = offsetof(struct crypto_rng, base),
17f0f4a4	116	};
17f0f4a4	117
d0e83059 HX	118	struct crypto_rng crypto_alloc_rng(const char alg_name, u32 type, u32 mask)
	119	{
	120	return crypto_alloc_tfm(alg_name, &crypto_rng_type, type, mask);
	121	}
	122	EXPORT_SYMBOL_GPL(crypto_alloc_rng);
	123
17f0f4a4 NH	124	int crypto_get_default_rng(void)
	125	{
	126	struct crypto_rng *rng;
	127	int err;
	128
	129	mutex_lock(&crypto_default_rng_lock);
	130	if (!crypto_default_rng) {
	131	rng = crypto_alloc_rng("stdrng", 0, 0);
	132	err = PTR_ERR(rng);
	133	if (IS_ERR(rng))
	134	goto unlock;
	135
	136	err = crypto_rng_reset(rng, NULL, crypto_rng_seedsize(rng));
	137	if (err) {
	138	crypto_free_rng(rng);
	139	goto unlock;
	140	}
	141
	142	crypto_default_rng = rng;
	143	}
	144
	145	crypto_default_rng_refcnt++;
	146	err = 0;
	147
	148	unlock:
	149	mutex_unlock(&crypto_default_rng_lock);
	150
	151	return err;
	152	}
	153	EXPORT_SYMBOL_GPL(crypto_get_default_rng);
	154
	155	void crypto_put_default_rng(void)
	156	{
	157	mutex_lock(&crypto_default_rng_lock);
7cecadb7	158	crypto_default_rng_refcnt--;
17f0f4a4 NH	159	mutex_unlock(&crypto_default_rng_lock);
	160	}
	161	EXPORT_SYMBOL_GPL(crypto_put_default_rng);
	162
7cecadb7 HX	163	#if defined(CONFIG_CRYPTO_RNG) \|\| defined(CONFIG_CRYPTO_RNG_MODULE)
	164	int crypto_del_default_rng(void)
	165	{
	166	int err = -EBUSY;
	167
	168	mutex_lock(&crypto_default_rng_lock);
	169	if (crypto_default_rng_refcnt)
	170	goto out;
	171
	172	crypto_free_rng(crypto_default_rng);
	173	crypto_default_rng = NULL;
	174
	175	err = 0;
	176
	177	out:
	178	mutex_unlock(&crypto_default_rng_lock);
	179
	180	return err;
	181	}
	182	EXPORT_SYMBOL_GPL(crypto_del_default_rng);
	183	#endif
	184
acec27ff HX	185	int crypto_register_rng(struct rng_alg *alg)
	186	{
	187	struct crypto_alg *base = &alg->base;
	188
	189	if (alg->seedsize > PAGE_SIZE / 8)
	190	return -EINVAL;
	191
	192	base->cra_type = &crypto_rng_type;
	193	base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
	194	base->cra_flags \|= CRYPTO_ALG_TYPE_RNG;
	195
	196	return crypto_register_alg(base);
	197	}
	198	EXPORT_SYMBOL_GPL(crypto_register_rng);
	199
	200	void crypto_unregister_rng(struct rng_alg *alg)
	201	{
	202	crypto_unregister_alg(&alg->base);
	203	}
	204	EXPORT_SYMBOL_GPL(crypto_unregister_rng);
	205
881cd6c5 HX	206	int crypto_register_rngs(struct rng_alg *algs, int count)
	207	{
	208	int i, ret;
	209
	210	for (i = 0; i < count; i++) {
	211	ret = crypto_register_rng(algs + i);
	212	if (ret)
	213	goto err;
	214	}
	215
	216	return 0;
	217
	218	err:
	219	for (--i; i >= 0; --i)
	220	crypto_unregister_rng(algs + i);
	221
	222	return ret;
	223	}
	224	EXPORT_SYMBOL_GPL(crypto_register_rngs);
	225
	226	void crypto_unregister_rngs(struct rng_alg *algs, int count)
	227	{
	228	int i;
	229
	230	for (i = count - 1; i >= 0; --i)
	231	crypto_unregister_rng(algs + i);
	232	}
	233	EXPORT_SYMBOL_GPL(crypto_unregister_rngs);
	234
17f0f4a4	235	MODULE_LICENSE("GPL");
a8ccc393	236	MODULE_DESCRIPTION("Random Number Generator");