128 lines
2.8 KiB
C
128 lines
2.8 KiB
C
/*
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* Cryptographic API.
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*
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* RNG operations.
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*
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* Copyright (c) 2008 Neil Horman <nhorman@tuxdriver.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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*/
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#include <linux/atomic.h>
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#include <crypto/internal/rng.h>
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#include <linux/err.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/random.h>
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#include <linux/seq_file.h>
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#include <linux/slab.h>
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#include <linux/string.h>
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static DEFINE_MUTEX(crypto_default_rng_lock);
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struct crypto_rng *crypto_default_rng;
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EXPORT_SYMBOL_GPL(crypto_default_rng);
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static int crypto_default_rng_refcnt;
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static int rngapi_reset(struct crypto_rng *tfm, u8 *seed, unsigned int slen)
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{
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u8 *buf = NULL;
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int err;
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if (!seed && slen) {
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buf = kmalloc(slen, GFP_KERNEL);
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if (!buf)
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return -ENOMEM;
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get_random_bytes(buf, slen);
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seed = buf;
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}
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err = crypto_rng_alg(tfm)->rng_reset(tfm, seed, slen);
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kfree(buf);
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return err;
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}
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static int crypto_init_rng_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
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{
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struct rng_alg *alg = &tfm->__crt_alg->cra_rng;
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struct rng_tfm *ops = &tfm->crt_rng;
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ops->rng_gen_random = alg->rng_make_random;
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ops->rng_reset = rngapi_reset;
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return 0;
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}
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static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg)
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__attribute__ ((unused));
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static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg)
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{
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seq_printf(m, "type : rng\n");
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seq_printf(m, "seedsize : %u\n", alg->cra_rng.seedsize);
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}
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static unsigned int crypto_rng_ctxsize(struct crypto_alg *alg, u32 type,
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u32 mask)
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{
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return alg->cra_ctxsize;
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}
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const struct crypto_type crypto_rng_type = {
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.ctxsize = crypto_rng_ctxsize,
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.init = crypto_init_rng_ops,
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#ifdef CONFIG_PROC_FS
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.show = crypto_rng_show,
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#endif
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};
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EXPORT_SYMBOL_GPL(crypto_rng_type);
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int crypto_get_default_rng(void)
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{
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struct crypto_rng *rng;
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int err;
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mutex_lock(&crypto_default_rng_lock);
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if (!crypto_default_rng) {
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rng = crypto_alloc_rng("stdrng", 0, 0);
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err = PTR_ERR(rng);
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if (IS_ERR(rng))
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goto unlock;
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err = crypto_rng_reset(rng, NULL, crypto_rng_seedsize(rng));
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if (err) {
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crypto_free_rng(rng);
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goto unlock;
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}
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crypto_default_rng = rng;
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}
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crypto_default_rng_refcnt++;
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err = 0;
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unlock:
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mutex_unlock(&crypto_default_rng_lock);
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return err;
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}
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EXPORT_SYMBOL_GPL(crypto_get_default_rng);
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void crypto_put_default_rng(void)
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{
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mutex_lock(&crypto_default_rng_lock);
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if (!--crypto_default_rng_refcnt) {
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crypto_free_rng(crypto_default_rng);
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crypto_default_rng = NULL;
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}
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mutex_unlock(&crypto_default_rng_lock);
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}
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EXPORT_SYMBOL_GPL(crypto_put_default_rng);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("Random Number Generator");
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