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/*
* 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 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_rng_init_tfm(struct crypto_tfm *tfm)
{
struct crypto_rng *rng = __crypto_rng_cast(tfm);
struct rng_alg *alg = &tfm->__crt_alg->cra_rng;
rng->generate = alg->rng_make_random;
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");
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