From: Stephan Mueller Date: Wed, 12 Nov 2014 04:27:16 +0000 (+0100) Subject: crypto: doc - SHASH API documentation X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=968ab291078006de022b2245702a050ccdc32cd3;p=openwrt%2Fstaging%2Fblogic.git crypto: doc - SHASH API documentation The API function calls exported by the kernel crypto API for SHASHes to be used by consumers are documented. Signed-off-by: Stephan Mueller Signed-off-by: Herbert Xu --- diff --git a/include/crypto/hash.h b/include/crypto/hash.h index b2c193acc1ab..3d66e8bd0932 100644 --- a/include/crypto/hash.h +++ b/include/crypto/hash.h @@ -583,6 +583,33 @@ static inline void ahash_request_set_crypt(struct ahash_request *req, req->result = result; } +/** + * DOC: Synchronous Message Digest API + * + * The synchronous message digest API is used with the ciphers of type + * CRYPTO_ALG_TYPE_SHASH (listed as type "shash" in /proc/crypto) + * + * The message digest API is able to maintain state information for the + * caller. + * + * The synchronous message digest API can store user-related context in in its + * shash_desc request data structure. + */ + +/** + * crypto_alloc_shash() - allocate message digest 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 message digest. The returned &struct + * crypto_shash is the cipher handle that is required for any subsequent + * API invocation for that message digest. + * + * 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_shash *crypto_alloc_shash(const char *alg_name, u32 type, u32 mask); @@ -591,6 +618,10 @@ static inline struct crypto_tfm *crypto_shash_tfm(struct crypto_shash *tfm) return &tfm->base; } +/** + * crypto_free_shash() - zeroize and free the message digest handle + * @tfm: cipher handle to be freed + */ static inline void crypto_free_shash(struct crypto_shash *tfm) { crypto_destroy_tfm(tfm, crypto_shash_tfm(tfm)); @@ -602,6 +633,15 @@ static inline unsigned int crypto_shash_alignmask( return crypto_tfm_alg_alignmask(crypto_shash_tfm(tfm)); } +/** + * crypto_shash_blocksize() - obtain block size for cipher + * @tfm: cipher handle + * + * The block size for the message digest cipher referenced with the cipher + * handle is returned. + * + * Return: block size of cipher + */ static inline unsigned int crypto_shash_blocksize(struct crypto_shash *tfm) { return crypto_tfm_alg_blocksize(crypto_shash_tfm(tfm)); @@ -617,6 +657,15 @@ static inline struct shash_alg *crypto_shash_alg(struct crypto_shash *tfm) return __crypto_shash_alg(crypto_shash_tfm(tfm)->__crt_alg); } +/** + * crypto_shash_digestsize() - obtain message digest size + * @tfm: cipher handle + * + * The size for the message digest created by the message digest cipher + * referenced with the cipher handle is returned. + * + * Return: digest size of cipher + */ static inline unsigned int crypto_shash_digestsize(struct crypto_shash *tfm) { return crypto_shash_alg(tfm)->digestsize; @@ -642,6 +691,21 @@ static inline void crypto_shash_clear_flags(struct crypto_shash *tfm, u32 flags) crypto_tfm_clear_flags(crypto_shash_tfm(tfm), flags); } +/** + * crypto_shash_descsize() - obtain the operational state size + * @tfm: cipher handle + * + * The size of the operational state the cipher needs during operation is + * returned for the hash referenced with the cipher handle. This size is + * required to calculate the memory requirements to allow the caller allocating + * sufficient memory for operational state. + * + * The operational state is defined with struct shash_desc where the size of + * that data structure is to be calculated as + * sizeof(struct shash_desc) + crypto_shash_descsize(alg) + * + * Return: size of the operational state + */ static inline unsigned int crypto_shash_descsize(struct crypto_shash *tfm) { return tfm->descsize; @@ -652,29 +716,129 @@ static inline void *shash_desc_ctx(struct shash_desc *desc) return desc->__ctx; } +/** + * crypto_shash_setkey() - set key for message digest + * @tfm: cipher handle + * @key: buffer holding the key + * @keylen: length of the key in bytes + * + * The caller provided key is set for the keyed message digest cipher. The + * cipher handle must point to a keyed message digest cipher in order for this + * function to succeed. + * + * Return: 0 if the setting of the key was successful; < 0 if an error occurred + */ int crypto_shash_setkey(struct crypto_shash *tfm, const u8 *key, unsigned int keylen); + +/** + * crypto_shash_digest() - calculate message digest for buffer + * @desc: see crypto_shash_final() + * @data: see crypto_shash_update() + * @len: see crypto_shash_update() + * @out: see crypto_shash_final() + * + * This function is a "short-hand" for the function calls of crypto_shash_init, + * crypto_shash_update and crypto_shash_final. The parameters have the same + * meaning as discussed for those separate three functions. + * + * Return: 0 if the message digest creation was successful; < 0 if an error + * occurred + */ int crypto_shash_digest(struct shash_desc *desc, const u8 *data, unsigned int len, u8 *out); +/** + * crypto_shash_export() - extract operational state for message digest + * @desc: reference to the operational state handle whose state is exported + * @out: output buffer of sufficient size that can hold the hash state + * + * This function exports the hash state of the operational state handle into the + * caller-allocated output buffer out which must have sufficient size (e.g. by + * calling crypto_shash_descsize). + * + * Return: 0 if the export creation was successful; < 0 if an error occurred + */ static inline int crypto_shash_export(struct shash_desc *desc, void *out) { return crypto_shash_alg(desc->tfm)->export(desc, out); } +/** + * crypto_shash_import() - import operational state + * @desc: reference to the operational state handle the state imported into + * @in: buffer holding the state + * + * This function imports the hash state into the operational state handle from + * the input buffer. That buffer should have been generated with the + * crypto_ahash_export function. + * + * Return: 0 if the import was successful; < 0 if an error occurred + */ static inline int crypto_shash_import(struct shash_desc *desc, const void *in) { return crypto_shash_alg(desc->tfm)->import(desc, in); } +/** + * crypto_shash_init() - (re)initialize message digest + * @desc: operational state handle that is already filled + * + * The call (re-)initializes the message digest referenced by the + * operational state handle. Any potentially existing state created by + * previous operations is discarded. + * + * Return: 0 if the message digest initialization was successful; < 0 if an + * error occurred + */ static inline int crypto_shash_init(struct shash_desc *desc) { return crypto_shash_alg(desc->tfm)->init(desc); } +/** + * crypto_shash_update() - add data to message digest for processing + * @desc: operational state handle that is already initialized + * @data: input data to be added to the message digest + * @len: length of the input data + * + * Updates the message digest state of the operational state handle. + * + * Return: 0 if the message digest update was successful; < 0 if an error + * occurred + */ int crypto_shash_update(struct shash_desc *desc, const u8 *data, unsigned int len); + +/** + * crypto_shash_final() - calculate message digest + * @desc: operational state handle that is already filled with data + * @out: output buffer filled with the message digest + * + * Finalize the message digest operation and create the message digest + * based on all data added to the cipher handle. The message digest is placed + * into the output buffer. The caller must ensure that the output buffer is + * large enough by using crypto_shash_digestsize. + * + * Return: 0 if the message digest creation was successful; < 0 if an error + * occurred + */ int crypto_shash_final(struct shash_desc *desc, u8 *out); + +/** + * crypto_shash_finup() - calculate message digest of buffer + * @desc: see crypto_shash_final() + * @data: see crypto_shash_update() + * @len: see crypto_shash_update() + * @out: see crypto_shash_final() + * + * This function is a "short-hand" for the function calls of + * crypto_shash_update and crypto_shash_final. The parameters have the same + * meaning as discussed for those separate functions. + * + * Return: 0 if the message digest creation was successful; < 0 if an error + * occurred + */ int crypto_shash_finup(struct shash_desc *desc, const u8 *data, unsigned int len, u8 *out);