// SPDX-License-Identifier: GPL-2.0-or-later/* * Cryptographic API. * * RNG operations. * * Copyright (c) 2008 Neil Horman <nhorman@tuxdriver.com> * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au> */ #include <crypto/internal/rng.h>#include <linux/atomic.h>#include <linux/cryptouser.h>#include <linux/err.h>#include <linux/kernel.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 <net/netlink.h> #include "internal.h" static DEFINE_MUTEX(crypto_default_rng_lock);static struct crypto_rng *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:	kfree_sensitive(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;} static int __maybe_unused crypto_rng_report(	struct sk_buff *skb, struct crypto_alg *alg){	struct crypto_report_rng rrng = {		.type = "rng",	}; 	rrng.seedsize = seedsize(alg); 	return nla_put(skb, CRYPTOCFGA_REPORT_RNG, sizeof(rrng), &rrng);} static void __maybe_unused 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#if IS_ENABLED(CONFIG_CRYPTO_USER)	.report = crypto_rng_report,#endif	.maskclear = ~CRYPTO_ALG_TYPE_MASK,	.maskset = CRYPTO_ALG_TYPE_MASK,	.type = CRYPTO_ALG_TYPE_RNG,	.tfmsize = offsetof(struct crypto_rng, base),	.algsize = offsetof(struct rng_alg, 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); static 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;} static void crypto_put_default_rng(void){	mutex_lock(&crypto_default_rng_lock);	crypto_default_rng_refcnt--;	mutex_unlock(&crypto_default_rng_lock);} int __crypto_stdrng_get_bytes(void *buf, unsigned int len){	int err; 	err = crypto_get_default_rng();	if (err)		return err; 	err = crypto_rng_get_bytes(crypto_default_rng, buf, len);	crypto_put_default_rng();	return err;}EXPORT_SYMBOL_GPL(__crypto_stdrng_get_bytes); #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 static void rng_default_set_ent(struct crypto_rng *tfm, const u8 *data,				unsigned int len){} 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; 	if (!alg->set_ent)		alg->set_ent = rng_default_set_ent; 	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) {			crypto_unregister_rngs(algs, i);			return ret;		}	} 	return 0;}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); static void __exit rng_exit(void){	int err; 	err = crypto_del_default_rng();	if (err)		pr_err("Failed delete default RNG: %d\n", err);} module_exit(rng_exit); MODULE_LICENSE("GPL");MODULE_DESCRIPTION("Random Number Generator");