From aa1b6fbcbeaca21038db3e7a98d739786ae93511 Mon Sep 17 00:00:00 2001 From: Stephan Mueller Date: Wed, 12 Nov 2014 05:25:31 +0100 Subject: crypto: doc - RNG API documentation The API function calls exported by the kernel crypto API for RNGs to be used by consumers are documented. Signed-off-by: Stephan Mueller Signed-off-by: Herbert Xu --- include/crypto/rng.h | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 80 insertions(+) (limited to 'include/crypto') diff --git a/include/crypto/rng.h b/include/crypto/rng.h index c93f9b917925..a16fb10142bf 100644 --- a/include/crypto/rng.h +++ b/include/crypto/rng.h @@ -20,11 +20,38 @@ 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) + */ + static inline struct crypto_rng *__crypto_rng_cast(struct crypto_tfm *tfm) { return (struct crypto_rng *)tfm; } +/** + * 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. + */ static inline struct crypto_rng *crypto_alloc_rng(const char *alg_name, u32 type, u32 mask) { @@ -40,6 +67,14 @@ 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 &crypto_rng_tfm(tfm)->__crt_alg->cra_rng; @@ -50,23 +85,68 @@ static inline struct rng_tfm *crypto_rng_crt(struct crypto_rng *tfm) return &crypto_rng_tfm(tfm)->crt_rng; } +/** + * 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_free_tfm(crypto_rng_tfm(tfm)); } +/** + * 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 and returns the number of generated + * bytes; < 0 if an error occurred + */ static inline int crypto_rng_get_bytes(struct crypto_rng *tfm, u8 *rdata, unsigned int dlen) { return crypto_rng_crt(tfm)->rng_gen_random(tfm, 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 + */ static inline int crypto_rng_reset(struct crypto_rng *tfm, u8 *seed, unsigned int slen) { return crypto_rng_crt(tfm)->rng_reset(tfm, seed, 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; -- cgit v1.2.3-59-g8ed1b