/* * 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 <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; static inline struct crypto_rng *__crypto_rng_cast(struct crypto_tfm *tfm) { return container_of(tfm, struct crypto_rng, base); } 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; get_random_bytes(buf, slen); seed = buf; } err = crypto_rng_alg(tfm)->seed(tfm, seed, slen); 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) __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", 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");