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

/*
 * Cryptographic API.
 *
 * RNG operations.
 *
 * Copyright (c) 2008 Neil Horman <nhorman@tuxdriver.com>
 *
 * 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>

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;
}

#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 = alg->cra_rng.seedsize;

	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", 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
	.report = crypto_rng_report,
};
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 <nhorman@tuxdriver.com>
	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
60063497	15	#include <linux/atomic.h>
17f0f4a4 NH	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	23	#include <linux/string.h>
792608e9 SK	24	#include <linux/cryptouser.h>
792608e9 SK	25	#include <net/netlink.h>
17f0f4a4 NH	26
	27	static DEFINE_MUTEX(crypto_default_rng_lock);
	28	struct crypto_rng *crypto_default_rng;
	29	EXPORT_SYMBOL_GPL(crypto_default_rng);
	30	static int crypto_default_rng_refcnt;
	31
	32	static int rngapi_reset(struct crypto_rng tfm, u8 seed, unsigned int slen)
	33	{
	34	u8 *buf = NULL;
	35	int err;
	36
	37	if (!seed && slen) {
	38	buf = kmalloc(slen, GFP_KERNEL);
	39	if (!buf)
	40	return -ENOMEM;
	41
	42	get_random_bytes(buf, slen);
	43	seed = buf;
	44	}
	45
	46	err = crypto_rng_alg(tfm)->rng_reset(tfm, seed, slen);
	47
	48	kfree(buf);
	49	return err;
	50	}
	51
	52	static int crypto_init_rng_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
	53	{
	54	struct rng_alg *alg = &tfm->__crt_alg->cra_rng;
	55	struct rng_tfm *ops = &tfm->crt_rng;
	56
	57	ops->rng_gen_random = alg->rng_make_random;
	58	ops->rng_reset = rngapi_reset;
	59
	60	return 0;
	61	}
	62
3acc8473	63	#ifdef CONFIG_NET
792608e9 SK	64	static int crypto_rng_report(struct sk_buff skb, struct crypto_alg alg)
	65	{
	66	struct crypto_report_rng rrng;
	67
9a5467bf	68	strncpy(rrng.type, "rng", sizeof(rrng.type));
792608e9 SK	69
	70	rrng.seedsize = alg->cra_rng.seedsize;
	71
6662df33 DM	72	if (nla_put(skb, CRYPTOCFGA_REPORT_RNG,
	73	sizeof(struct crypto_report_rng), &rrng))
	74	goto nla_put_failure;
792608e9 SK	75	return 0;
	76
	77	nla_put_failure:
	78	return -EMSGSIZE;
	79	}
3acc8473 HX	80	#else
	81	static int crypto_rng_report(struct sk_buff skb, struct crypto_alg alg)
	82	{
	83	return -ENOSYS;
	84	}
	85	#endif
792608e9	86
17f0f4a4 NH	87	static void crypto_rng_show(struct seq_file m, struct crypto_alg alg)
	88	__attribute__ ((unused));
	89	static void crypto_rng_show(struct seq_file m, struct crypto_alg alg)
	90	{
	91	seq_printf(m, "type : rng\n");
	92	seq_printf(m, "seedsize : %u\n", alg->cra_rng.seedsize);
	93	}
	94
	95	static unsigned int crypto_rng_ctxsize(struct crypto_alg *alg, u32 type,
	96	u32 mask)
	97	{
	98	return alg->cra_ctxsize;
	99	}
	100
	101	const struct crypto_type crypto_rng_type = {
	102	.ctxsize = crypto_rng_ctxsize,
	103	.init = crypto_init_rng_ops,
	104	#ifdef CONFIG_PROC_FS
	105	.show = crypto_rng_show,
	106	#endif
792608e9	107	.report = crypto_rng_report,
17f0f4a4 NH	108	};
	109	EXPORT_SYMBOL_GPL(crypto_rng_type);
	110
	111	int crypto_get_default_rng(void)
	112	{
	113	struct crypto_rng *rng;
	114	int err;
	115
	116	mutex_lock(&crypto_default_rng_lock);
	117	if (!crypto_default_rng) {
	118	rng = crypto_alloc_rng("stdrng", 0, 0);
	119	err = PTR_ERR(rng);
	120	if (IS_ERR(rng))
	121	goto unlock;
	122
	123	err = crypto_rng_reset(rng, NULL, crypto_rng_seedsize(rng));
	124	if (err) {
	125	crypto_free_rng(rng);
	126	goto unlock;
	127	}
	128
	129	crypto_default_rng = rng;
	130	}
	131
	132	crypto_default_rng_refcnt++;
	133	err = 0;
	134
	135	unlock:
	136	mutex_unlock(&crypto_default_rng_lock);
	137
	138	return err;
	139	}
	140	EXPORT_SYMBOL_GPL(crypto_get_default_rng);
	141
	142	void crypto_put_default_rng(void)
	143	{
	144	mutex_lock(&crypto_default_rng_lock);
	145	if (!--crypto_default_rng_refcnt) {
	146	crypto_free_rng(crypto_default_rng);
	147	crypto_default_rng = NULL;
	148	}
	149	mutex_unlock(&crypto_default_rng_lock);
	150	}
	151	EXPORT_SYMBOL_GPL(crypto_put_default_rng);
	152
	153	MODULE_LICENSE("GPL");
a8ccc393	154	MODULE_DESCRIPTION("Random Number Generator");