[linux.git] / crypto / rng.c

/*
 * Cryptographic API.
 *
 * RNG operations.
 *
 * Copyright (c) 2008 Neil Horman <[email protected]>
 *
 * 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 <asm/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>

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 int rngapi_reset(struct crypto_rng *tfm, 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)->rng_reset(tfm, seed, slen);

	kfree(buf);
	return err;
}

static int crypto_init_rng_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
{
	struct rng_alg *alg = &tfm->__crt_alg->cra_rng;
	struct rng_tfm *ops = &tfm->crt_rng;

	ops->rng_gen_random = alg->rng_make_random;
	ops->rng_reset = rngapi_reset;

	return 0;
}

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", alg->cra_rng.seedsize);
}

static unsigned int crypto_rng_ctxsize(struct crypto_alg *alg, u32 type,
				       u32 mask)
{
	return alg->cra_ctxsize;
}

const struct crypto_type crypto_rng_type = {
	.ctxsize = crypto_rng_ctxsize,
	.init = crypto_init_rng_ops,
#ifdef CONFIG_PROC_FS
	.show = crypto_rng_show,
#endif
};
EXPORT_SYMBOL_GPL(crypto_rng_type);

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);
	if (!--crypto_default_rng_refcnt) {
		crypto_free_rng(crypto_default_rng);
		crypto_default_rng = NULL;
	}
	mutex_unlock(&crypto_default_rng_lock);
}
EXPORT_SYMBOL_GPL(crypto_put_default_rng);

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 <[email protected]>
	7	*
	8	* This program is free software; you can redistribute it and/or modify it
	9	* under the terms of the GNU General Public License as published by the Free
	10	* Software Foundation; either version 2 of the License, or (at your option)
	11	* any later version.
	12	*
	13	*/
	14
	15	#include <asm/atomic.h>
	16	#include <crypto/internal/rng.h>
	17	#include <linux/err.h>
	18	#include <linux/module.h>
	19	#include <linux/mutex.h>
	20	#include <linux/random.h>
	21	#include <linux/seq_file.h>
5a0e3ad6	22	#include <linux/slab.h>
17f0f4a4 NH	23	#include <linux/string.h>
	24
	25	static DEFINE_MUTEX(crypto_default_rng_lock);
	26	struct crypto_rng *crypto_default_rng;
	27	EXPORT_SYMBOL_GPL(crypto_default_rng);
	28	static int crypto_default_rng_refcnt;
	29
	30	static int rngapi_reset(struct crypto_rng tfm, u8 seed, unsigned int slen)
	31	{
	32	u8 *buf = NULL;
	33	int err;
	34
	35	if (!seed && slen) {
	36	buf = kmalloc(slen, GFP_KERNEL);
	37	if (!buf)
	38	return -ENOMEM;
	39
	40	get_random_bytes(buf, slen);
	41	seed = buf;
	42	}
	43
	44	err = crypto_rng_alg(tfm)->rng_reset(tfm, seed, slen);
	45
	46	kfree(buf);
	47	return err;
	48	}
	49
	50	static int crypto_init_rng_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
	51	{
	52	struct rng_alg *alg = &tfm->__crt_alg->cra_rng;
	53	struct rng_tfm *ops = &tfm->crt_rng;
	54
	55	ops->rng_gen_random = alg->rng_make_random;
	56	ops->rng_reset = rngapi_reset;
	57
	58	return 0;
	59	}
	60
	61	static void crypto_rng_show(struct seq_file m, struct crypto_alg alg)
	62	__attribute__ ((unused));
	63	static void crypto_rng_show(struct seq_file m, struct crypto_alg alg)
	64	{
	65	seq_printf(m, "type : rng\n");
	66	seq_printf(m, "seedsize : %u\n", alg->cra_rng.seedsize);
	67	}
	68
	69	static unsigned int crypto_rng_ctxsize(struct crypto_alg *alg, u32 type,
	70	u32 mask)
	71	{
	72	return alg->cra_ctxsize;
	73	}
	74
	75	const struct crypto_type crypto_rng_type = {
	76	.ctxsize = crypto_rng_ctxsize,
	77	.init = crypto_init_rng_ops,
	78	#ifdef CONFIG_PROC_FS
	79	.show = crypto_rng_show,
	80	#endif
	81	};
	82	EXPORT_SYMBOL_GPL(crypto_rng_type);
	83
	84	int crypto_get_default_rng(void)
	85	{
	86	struct crypto_rng *rng;
87	int err;
88
89	mutex_lock(&crypto_default_rng_lock);
90	if (!crypto_default_rng) {
91	rng = crypto_alloc_rng("stdrng", 0, 0);
92	err = PTR_ERR(rng);
93	if (IS_ERR(rng))
94	goto unlock;
95
96	err = crypto_rng_reset(rng, NULL, crypto_rng_seedsize(rng));
97	if (err) {
98	crypto_free_rng(rng);
99	goto unlock;
100	}
101
102	crypto_default_rng = rng;
103	}
104
105	crypto_default_rng_refcnt++;
106	err = 0;
107
108	unlock:
109	mutex_unlock(&crypto_default_rng_lock);
110
111	return err;
112	}
113	EXPORT_SYMBOL_GPL(crypto_get_default_rng);
114
115	void crypto_put_default_rng(void)
116	{
117	mutex_lock(&crypto_default_rng_lock);
118	if (!--crypto_default_rng_refcnt) {
119	crypto_free_rng(crypto_default_rng);
120	crypto_default_rng = NULL;
121	}
122	mutex_unlock(&crypto_default_rng_lock);
123	}
124	EXPORT_SYMBOL_GPL(crypto_put_default_rng);
125
126	MODULE_LICENSE("GPL");
a8ccc393	127	MODULE_DESCRIPTION("Random Number Generator");