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Diffstat (limited to 'include/crypto/rng.h')
| -rw-r--r-- | include/crypto/rng.h | 203 |
1 files changed, 203 insertions, 0 deletions
diff --git a/include/crypto/rng.h b/include/crypto/rng.h new file mode 100644 index 000000000..17bb3673d --- /dev/null +++ b/include/crypto/rng.h @@ -0,0 +1,203 @@ +/* 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/crypto.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; +}; + +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 + * + * 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) +{ + struct crypto_alg *alg = tfm->base.__crt_alg; + int ret; + + crypto_stats_get(alg); + ret = crypto_rng_alg(tfm)->generate(tfm, src, slen, dst, dlen); + crypto_stats_rng_generate(alg, dlen, ret); + return ret; +} + +/** + * 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 |