diff options
Diffstat (limited to 'crypto/rng.c')
| -rw-r--r-- | crypto/rng.c | 234 |
1 files changed, 234 insertions, 0 deletions
diff --git a/crypto/rng.c b/crypto/rng.c new file mode 100644 index 000000000..b4a618668 --- /dev/null +++ b/crypto/rng.c @@ -0,0 +1,234 @@ +/* + * Cryptographic API. + * + * RNG operations. + * + * Copyright (c) 2008 Neil Horman <nhorman@tuxdriver.com> + * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au> + * + * 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 <linux/compiler.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; + +int crypto_rng_reset(struct crypto_rng *tfm, const u8 *seed, unsigned int slen) +{ + u8 *buf = NULL; + int err; + + if (!seed && slen) { + buf = kmalloc(slen, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + err = get_random_bytes_wait(buf, slen); + if (err) + goto out; + seed = buf; + } + + err = crypto_rng_alg(tfm)->seed(tfm, seed, slen); +out: + kzfree(buf); + return err; +} +EXPORT_SYMBOL_GPL(crypto_rng_reset); + +static int crypto_rng_init_tfm(struct crypto_tfm *tfm) +{ + return 0; +} + +static unsigned int seedsize(struct crypto_alg *alg) +{ + struct rng_alg *ralg = container_of(alg, struct rng_alg, base); + + return ralg->seedsize; +} + +#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 = seedsize(alg); + + 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) + __maybe_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", seedsize(alg)); +} + +static 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), +}; + +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); + crypto_default_rng_refcnt--; + mutex_unlock(&crypto_default_rng_lock); +} +EXPORT_SYMBOL_GPL(crypto_put_default_rng); + +#if defined(CONFIG_CRYPTO_RNG) || defined(CONFIG_CRYPTO_RNG_MODULE) +int crypto_del_default_rng(void) +{ + int err = -EBUSY; + + mutex_lock(&crypto_default_rng_lock); + if (crypto_default_rng_refcnt) + goto out; + + crypto_free_rng(crypto_default_rng); + crypto_default_rng = NULL; + + err = 0; + +out: + mutex_unlock(&crypto_default_rng_lock); + + return err; +} +EXPORT_SYMBOL_GPL(crypto_del_default_rng); +#endif + +int crypto_register_rng(struct rng_alg *alg) +{ + struct crypto_alg *base = &alg->base; + + if (alg->seedsize > PAGE_SIZE / 8) + return -EINVAL; + + base->cra_type = &crypto_rng_type; + base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK; + base->cra_flags |= CRYPTO_ALG_TYPE_RNG; + + return crypto_register_alg(base); +} +EXPORT_SYMBOL_GPL(crypto_register_rng); + +void crypto_unregister_rng(struct rng_alg *alg) +{ + crypto_unregister_alg(&alg->base); +} +EXPORT_SYMBOL_GPL(crypto_unregister_rng); + +int crypto_register_rngs(struct rng_alg *algs, int count) +{ + int i, ret; + + for (i = 0; i < count; i++) { + ret = crypto_register_rng(algs + i); + if (ret) + goto err; + } + + return 0; + +err: + for (--i; i >= 0; --i) + crypto_unregister_rng(algs + i); + + return ret; +} +EXPORT_SYMBOL_GPL(crypto_register_rngs); + +void crypto_unregister_rngs(struct rng_alg *algs, int count) +{ + int i; + + for (i = count - 1; i >= 0; --i) + crypto_unregister_rng(algs + i); +} +EXPORT_SYMBOL_GPL(crypto_unregister_rngs); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Random Number Generator"); |