| // 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 <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) |
| { |
| struct crypto_alg *alg = tfm->base.__crt_alg; |
| 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; |
| } |
| |
| crypto_stats_get(alg); |
| err = crypto_rng_alg(tfm)->seed(tfm, seed, slen); |
| crypto_stats_rng_seed(alg, err); |
| 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; |
| |
| memset(&rrng, 0, sizeof(rrng)); |
| |
| strscpy(rrng.type, "rng", sizeof(rrng.type)); |
| |
| rrng.seedsize = seedsize(alg); |
| |
| return nla_put(skb, CRYPTOCFGA_REPORT_RNG, sizeof(rrng), &rrng); |
| } |
| #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"); |