/* SPDX-License-Identifier: GPL-2.0-or-later *//* * RNG: Random Number Generator  algorithms under the crypto API * * Copyright (c) 2008 Neil Horman <nhorman@tuxdriver.com> * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au> */ #ifndef _CRYPTO_RNG_H#define _CRYPTO_RNG_H #include <linux/atomic.h>#include <linux/container_of.h>#include <linux/crypto.h>#include <linux/fips.h>#include <linux/random.h> struct crypto_rng; /** * struct rng_alg - random number generator definition * * @generate:	The function defined by this variable obtains a *		random number. The random number generator transform *		must generate the random number out of the context *		provided with this call, plus any additional data *		if provided to the call. * @seed:	Seed or reseed the random number generator.  With the *		invocation of this function call, the random number *		generator shall become ready for generation.  If the *		random number generator requires a seed for setting *		up a new state, the seed must be provided by the *		consumer while invoking this function. The required *		size of the seed is defined with @seedsize . * @set_ent:	Set entropy that would otherwise be obtained from *		entropy source.  Internal use only. * @seedsize:	The seed size required for a random number generator *		initialization defined with this variable. Some *		random number generators does not require a seed *		as the seeding is implemented internally without *		the need of support by the consumer. In this case, *		the seed size is set to zero. * @base:	Common crypto API algorithm data structure. */struct rng_alg {	int (*generate)(struct crypto_rng *tfm,			const u8 *src, unsigned int slen,			u8 *dst, unsigned int dlen);	int (*seed)(struct crypto_rng *tfm, const u8 *seed, unsigned int slen);	void (*set_ent)(struct crypto_rng *tfm, const u8 *data,			unsigned int len); 	unsigned int seedsize; 	struct crypto_alg base;}; struct crypto_rng {	struct crypto_tfm base;}; int __crypto_stdrng_get_bytes(void *buf, unsigned int len); /** * crypto_stdrng_get_bytes() - get cryptographically secure random bytes * @buf: output buffer holding the random numbers * @len: length of the output buffer * * This function fills the caller-allocated buffer with random numbers using the * normal Linux RNG if fips_enabled=0, or the highest-priority "stdrng" * algorithm in the crypto_rng subsystem if fips_enabled=1. * * Context: May sleep * Return: 0 function was successful; < 0 if an error occurred */static inline int crypto_stdrng_get_bytes(void *buf, unsigned int len){	might_sleep();	if (fips_enabled)		return __crypto_stdrng_get_bytes(buf, len);	return get_random_bytes_wait(buf, len);} /** * DOC: Random number generator API * * The random number generator API is used with the ciphers of type * CRYPTO_ALG_TYPE_RNG (listed as type "rng" in /proc/crypto) */ /** * crypto_alloc_rng() -- allocate RNG handle * @alg_name: is the cra_name / name or cra_driver_name / driver name of the *	      message digest cipher * @type: specifies the type of the cipher * @mask: specifies the mask for the cipher * * Allocate a cipher handle for a random number generator. The returned struct * crypto_rng is the cipher handle that is required for any subsequent * API invocation for that random number generator. * * For all random number generators, this call creates a new private copy of * the random number generator that does not share a state with other * instances. The only exception is the "krng" random number generator which * is a kernel crypto API use case for the get_random_bytes() function of the * /dev/random driver. * * Return: allocated cipher handle in case of success; IS_ERR() is true in case *	   of an error, PTR_ERR() returns the error code. */struct crypto_rng *crypto_alloc_rng(const char *alg_name, u32 type, u32 mask); static inline struct crypto_tfm *crypto_rng_tfm(struct crypto_rng *tfm){	return &tfm->base;} static inline struct rng_alg *__crypto_rng_alg(struct crypto_alg *alg){	return container_of(alg, struct rng_alg, base);} /** * crypto_rng_alg() - obtain 'struct rng_alg' pointer from RNG handle * @tfm: RNG handle * * Return: Pointer to 'struct rng_alg', derived from @tfm RNG handle */static inline struct rng_alg *crypto_rng_alg(struct crypto_rng *tfm){	return __crypto_rng_alg(crypto_rng_tfm(tfm)->__crt_alg);} /** * crypto_free_rng() - zeroize and free RNG handle * @tfm: cipher handle to be freed * * If @tfm is a NULL or error pointer, this function does nothing. */static inline void crypto_free_rng(struct crypto_rng *tfm){	crypto_destroy_tfm(tfm, crypto_rng_tfm(tfm));} /** * crypto_rng_generate() - get random number * @tfm: cipher handle * @src: Input buffer holding additional data, may be NULL * @slen: Length of additional data * @dst: output buffer holding the random numbers * @dlen: length of the output buffer * * This function fills the caller-allocated buffer with random * numbers using the random number generator referenced by the * cipher handle. * * Return: 0 function was successful; < 0 if an error occurred */static inline int crypto_rng_generate(struct crypto_rng *tfm,				      const u8 *src, unsigned int slen,				      u8 *dst, unsigned int dlen){	return crypto_rng_alg(tfm)->generate(tfm, src, slen, dst, dlen);} /** * crypto_rng_get_bytes() - get random number * @tfm: cipher handle * @rdata: output buffer holding the random numbers * @dlen: length of the output buffer * * This function fills the caller-allocated buffer with random numbers using the * random number generator referenced by the cipher handle. * * Return: 0 function was successful; < 0 if an error occurred */static inline int crypto_rng_get_bytes(struct crypto_rng *tfm,				       u8 *rdata, unsigned int dlen){	return crypto_rng_generate(tfm, NULL, 0, rdata, dlen);} /** * crypto_rng_reset() - re-initialize the RNG * @tfm: cipher handle * @seed: seed input data * @slen: length of the seed input data * * The reset function completely re-initializes the random number generator * referenced by the cipher handle by clearing the current state. The new state * is initialized with the caller provided seed or automatically, depending on * the random number generator type. (The SP800-90A DRBGs perform an automatic * seeding.) The seed is provided as a parameter to this function call. The * provided seed should have the length of the seed size defined for the random * number generator as defined by crypto_rng_seedsize. * * Return: 0 if the setting of the key was successful; < 0 if an error occurred */int crypto_rng_reset(struct crypto_rng *tfm, const u8 *seed,		     unsigned int slen); /** * crypto_rng_seedsize() - obtain seed size of RNG * @tfm: cipher handle * * The function returns the seed size for the random number generator * referenced by the cipher handle. This value may be zero if the random * number generator does not implement or require a reseeding. For example, * the SP800-90A DRBGs implement an automated reseeding after reaching a * pre-defined threshold. * * Return: seed size for the random number generator */static inline int crypto_rng_seedsize(struct crypto_rng *tfm){	return crypto_rng_alg(tfm)->seedsize;} #endif