[linux-2.6-block.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>

#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);
}

static int generate(struct crypto_rng *tfm, const u8 *src, unsigned int slen,
		    u8 *dst, unsigned int dlen)
{
	return crypto_rng_alg(tfm)->rng_make_random(tfm, dst, dlen);
}

static int rngapi_reset(struct crypto_rng *tfm, const u8 *seed,
			unsigned int slen)
{
	u8 *buf = NULL;
	u8 *src = (u8 *)seed;
	int err;

	if (slen) {
		buf = kmalloc(slen, GFP_KERNEL);
		if (!buf)
			return -ENOMEM;

		memcpy(buf, seed, slen);
		src = buf;
	}

	err = crypto_rng_alg(tfm)->rng_reset(tfm, src, slen);

	kzfree(buf);
	return err;
}

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

	kfree(buf);
	return err;
}
EXPORT_SYMBOL_GPL(crypto_rng_reset);

static int crypto_rng_init_tfm(struct crypto_tfm *tfm)
{
	struct crypto_rng *rng = __crypto_rng_cast(tfm);

	rng->generate = generate;
	rng->seed = 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);
}

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),
};
EXPORT_SYMBOL_GPL(crypto_rng_type);

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);
	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	26
d0e83059 HX	27	#include "internal.h"
d0e83059 HX	28
17f0f4a4 NH	29	static DEFINE_MUTEX(crypto_default_rng_lock);
	30	struct crypto_rng *crypto_default_rng;
	31	EXPORT_SYMBOL_GPL(crypto_default_rng);
	32	static int crypto_default_rng_refcnt;
	33
d0e83059 HX	34	static inline struct crypto_rng __crypto_rng_cast(struct crypto_tfm tfm)
	35	{
	36	return container_of(tfm, struct crypto_rng, base);
	37	}
	38
ff030b09 HX	39	static int generate(struct crypto_rng tfm, const u8 src, unsigned int slen,
	40	u8 *dst, unsigned int dlen)
	41	{
	42	return crypto_rng_alg(tfm)->rng_make_random(tfm, dst, dlen);
	43	}
	44
3c5d8fa9 HX	45	static int rngapi_reset(struct crypto_rng tfm, const u8 seed,
	46	unsigned int slen)
	47	{
	48	u8 *buf = NULL;
	49	u8 src = (u8 )seed;
	50	int err;
	51
	52	if (slen) {
	53	buf = kmalloc(slen, GFP_KERNEL);
	54	if (!buf)
	55	return -ENOMEM;
	56
	57	memcpy(buf, seed, slen);
	58	src = buf;
	59	}
	60
	61	err = crypto_rng_alg(tfm)->rng_reset(tfm, src, slen);
	62
	63	kzfree(buf);
	64	return err;
	65	}
	66
	67	int crypto_rng_reset(struct crypto_rng tfm, const u8 seed, unsigned int slen)
17f0f4a4 NH	68	{
	69	u8 *buf = NULL;
	70	int err;
	71
	72	if (!seed && slen) {
	73	buf = kmalloc(slen, GFP_KERNEL);
	74	if (!buf)
	75	return -ENOMEM;
	76
	77	get_random_bytes(buf, slen);
	78	seed = buf;
	79	}
	80
3c5d8fa9	81	err = tfm->seed(tfm, seed, slen);
17f0f4a4 NH	82
	83	kfree(buf);
	84	return err;
	85	}
3c5d8fa9	86	EXPORT_SYMBOL_GPL(crypto_rng_reset);
17f0f4a4	87
d0e83059	88	static int crypto_rng_init_tfm(struct crypto_tfm *tfm)
17f0f4a4	89	{
d0e83059	90	struct crypto_rng *rng = __crypto_rng_cast(tfm);
17f0f4a4	91
ff030b09	92	rng->generate = generate;
d0e83059	93	rng->seed = rngapi_reset;
17f0f4a4 NH	94
	95	return 0;
	96	}
	97
3acc8473	98	#ifdef CONFIG_NET
792608e9 SK	99	static int crypto_rng_report(struct sk_buff skb, struct crypto_alg alg)
	100	{
	101	struct crypto_report_rng rrng;
	102
9a5467bf	103	strncpy(rrng.type, "rng", sizeof(rrng.type));
792608e9 SK	104
	105	rrng.seedsize = alg->cra_rng.seedsize;
	106
6662df33 DM	107	if (nla_put(skb, CRYPTOCFGA_REPORT_RNG,
	108	sizeof(struct crypto_report_rng), &rrng))
	109	goto nla_put_failure;
792608e9 SK	110	return 0;
	111
	112	nla_put_failure:
	113	return -EMSGSIZE;
	114	}
3acc8473 HX	115	#else
	116	static int crypto_rng_report(struct sk_buff skb, struct crypto_alg alg)
	117	{
	118	return -ENOSYS;
	119	}
	120	#endif
792608e9	121
17f0f4a4 NH	122	static void crypto_rng_show(struct seq_file m, struct crypto_alg alg)
	123	__attribute__ ((unused));
	124	static void crypto_rng_show(struct seq_file m, struct crypto_alg alg)
	125	{
	126	seq_printf(m, "type : rng\n");
	127	seq_printf(m, "seedsize : %u\n", alg->cra_rng.seedsize);
	128	}
	129
17f0f4a4	130	const struct crypto_type crypto_rng_type = {
d0e83059 HX	131	.extsize = crypto_alg_extsize,
d0e83059 HX	132	.init_tfm = crypto_rng_init_tfm,
17f0f4a4 NH	133	#ifdef CONFIG_PROC_FS
	134	.show = crypto_rng_show,
	135	#endif
792608e9	136	.report = crypto_rng_report,
d0e83059 HX	137	.maskclear = ~CRYPTO_ALG_TYPE_MASK,
	138	.maskset = CRYPTO_ALG_TYPE_MASK,
	139	.type = CRYPTO_ALG_TYPE_RNG,
	140	.tfmsize = offsetof(struct crypto_rng, base),
17f0f4a4 NH	141	};
	142	EXPORT_SYMBOL_GPL(crypto_rng_type);
	143
d0e83059 HX	144	struct crypto_rng crypto_alloc_rng(const char alg_name, u32 type, u32 mask)
	145	{
	146	return crypto_alloc_tfm(alg_name, &crypto_rng_type, type, mask);
	147	}
	148	EXPORT_SYMBOL_GPL(crypto_alloc_rng);
	149
17f0f4a4 NH	150	int crypto_get_default_rng(void)
	151	{
	152	struct crypto_rng *rng;
	153	int err;
	154
	155	mutex_lock(&crypto_default_rng_lock);
	156	if (!crypto_default_rng) {
	157	rng = crypto_alloc_rng("stdrng", 0, 0);
	158	err = PTR_ERR(rng);
	159	if (IS_ERR(rng))
	160	goto unlock;
	161
	162	err = crypto_rng_reset(rng, NULL, crypto_rng_seedsize(rng));
	163	if (err) {
	164	crypto_free_rng(rng);
	165	goto unlock;
	166	}
	167
	168	crypto_default_rng = rng;
	169	}
	170
	171	crypto_default_rng_refcnt++;
	172	err = 0;
	173
	174	unlock:
	175	mutex_unlock(&crypto_default_rng_lock);
	176
	177	return err;
	178	}
	179	EXPORT_SYMBOL_GPL(crypto_get_default_rng);
	180
	181	void crypto_put_default_rng(void)
	182	{
	183	mutex_lock(&crypto_default_rng_lock);
	184	if (!--crypto_default_rng_refcnt) {
	185	crypto_free_rng(crypto_default_rng);
	186	crypto_default_rng = NULL;
	187	}
	188	mutex_unlock(&crypto_default_rng_lock);
	189	}
	190	EXPORT_SYMBOL_GPL(crypto_put_default_rng);
	191
	192	MODULE_LICENSE("GPL");
a8ccc393	193	MODULE_DESCRIPTION("Random Number Generator");