127 lines
2.8 KiB
C
127 lines
2.8 KiB
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 <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/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");
|