/* * 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 Genertor");