diff options
Diffstat (limited to 'crypto/rng.c')
-rw-r--r-- | crypto/rng.c | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/crypto/rng.c b/crypto/rng.c new file mode 100644 index 0000000..6e94bc7 --- /dev/null +++ b/crypto/rng.c @@ -0,0 +1,126 @@ +/* + * 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"); |