/* * RNG: Random Number Generator algorithms under the crypto API * * Copyright (c) 2008 Neil Horman * Copyright (c) 2015 Herbert Xu * * 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. * */ #ifndef _CRYPTO_RNG_H #define _CRYPTO_RNG_H #include 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; }; extern struct crypto_rng *crypto_default_rng; int crypto_get_default_rng(void); void crypto_put_default_rng(void); /** * 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; } /** * crypto_rng_alg - obtain name of RNG * @tfm: cipher handle * * Return the generic name (cra_name) of the initialized random number generator * * Return: generic name string */ static inline struct rng_alg *crypto_rng_alg(struct crypto_rng *tfm) { return container_of(crypto_rng_tfm(tfm)->__crt_alg, struct rng_alg, base); } /** * crypto_free_rng() - zeroize and free RNG handle * @tfm: cipher handle to be freed */ 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 ANSI X9.31 RNG requires * caller-provided seed, 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 y Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20170118132921.19319-1-jslaby@suse.cz Signed-off-by: Ingo Molnar <mingo@kernel.org>
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