Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752923AbaKBUpe (ORCPT ); Sun, 2 Nov 2014 15:45:34 -0500 Received: from mail.eperm.de ([89.247.134.16]:54228 "EHLO mail.eperm.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752710AbaKBUn4 (ORCPT ); Sun, 2 Nov 2014 15:43:56 -0500 X-AuthUser: sm@eperm.de From: Stephan Mueller To: Herbert Xu Cc: "David S. Miller" , Marek Vasut , Jason Cooper , Grant Likely , Geert Uytterhoeven , Linux Kernel Developers List , linux-crypto@vger.kernel.org Subject: [PATCH v2 04/11] crypto: Documentation - AHASH API documentation Date: Sun, 02 Nov 2014 21:37:35 +0100 Message-ID: <3031970.r1C4nyeuS1@tachyon.chronox.de> User-Agent: KMail/4.14.1 (Linux/3.17.1-302.fc21.x86_64; KDE/4.14.1; x86_64; ; ) In-Reply-To: <6375771.bx7QqLJLuR@tachyon.chronox.de> References: <6375771.bx7QqLJLuR@tachyon.chronox.de> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The API function calls exported by the kernel crypto API for AHASHes to be used by consumers are documented. Signed-off-by: Stephan Mueller CC: Marek Vasut --- include/crypto/hash.h | 224 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 224 insertions(+) diff --git a/include/crypto/hash.h b/include/crypto/hash.h index 74b13ec..0d43dbc 100644 --- a/include/crypto/hash.h +++ b/include/crypto/hash.h @@ -107,11 +107,39 @@ struct crypto_shash { struct crypto_tfm base; }; +/** + * Asynchronous message digest API to use the ciphers of type + * CRYPTO_ALG_TYPE_AHASH (listed as type "ahash" in /proc/crypto) + * + * The asynchronous cipher operation discussion provided for the + * CRYPTO_ALG_TYPE_ABLKCIPHER API applies here as well. + * + * Example code: + * + * The example code given for the asynchronous block cipher operation can be + * used as a template where the ablkcipher function calls are swapped with ahash + * function calls. + */ + static inline struct crypto_ahash *__crypto_ahash_cast(struct crypto_tfm *tfm) { return container_of(tfm, struct crypto_ahash, base); } +/** + * Allocate a cipher handle for an ahash. The returned struct + * crypto_ahash is the cipher handle that is required for any subsequent + * API invocation for that ahash. + * + * @alg_name is the cra_name / name or cra_driver_name / driver name of the + * ahash cipher + * @type specifies the type of the cipher (see Documentation/crypto/) + * @mask specifies the mask for the cipher (see Documentation/crypto/) + * + * return value: + * allocated cipher handle in case of success + * IS_ERR() is true in case of an error, PTR_ERR() returns the error code. + */ struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type, u32 mask); @@ -120,6 +148,11 @@ static inline struct crypto_tfm *crypto_ahash_tfm(struct crypto_ahash *tfm) return &tfm->base; } +/** + * The referenced ahash handle is zeroized and subsequently freed. + * + * @tfm cipher handle to be freed + */ static inline void crypto_free_ahash(struct crypto_ahash *tfm) { crypto_destroy_tfm(tfm, crypto_ahash_tfm(tfm)); @@ -143,6 +176,15 @@ static inline struct hash_alg_common *crypto_hash_alg_common( return __crypto_hash_alg_common(crypto_ahash_tfm(tfm)->__crt_alg); } +/** + * The size for the message digest created by the message digest cipher + * referenced with the cipher handle is returned. + * + * @tfm cipher handle + * + * return value: + * block size of cipher + */ static inline unsigned int crypto_ahash_digestsize(struct crypto_ahash *tfm) { return crypto_hash_alg_common(tfm)->digestsize; @@ -168,12 +210,32 @@ static inline void crypto_ahash_clear_flags(struct crypto_ahash *tfm, u32 flags) crypto_tfm_clear_flags(crypto_ahash_tfm(tfm), flags); } +/** + * Return the ahash cipher handle that is registered with the asynchronous + * request handle ahash_request. + * + * @req asynchronous request handle that contains the reference to the ahash + * cipher handle + * + * return value: + * ahash cipher handle + */ static inline struct crypto_ahash *crypto_ahash_reqtfm( struct ahash_request *req) { return __crypto_ahash_cast(req->base.tfm); } +/** + * Return the size of the ahash state size. With the crypto_ahash_export + * function, the caller can export the state into a buffer whose size is + * defined with this function. + * + * @tfm cipher handle + * + * return value: + * size of the ahash state + */ static inline unsigned int crypto_ahash_reqsize(struct crypto_ahash *tfm) { return tfm->reqsize; @@ -184,38 +246,159 @@ static inline void *ahash_request_ctx(struct ahash_request *req) return req->__ctx; } +/** + * The caller provided key is set for the ahash cipher. The cipher + * handle must point to a keyed hash in order for this function to succeed. + * + * @tfm cipher handle + * @key buffer holding the key + * @keylen length of the key in bytes + * + * return value: + * 0 if the setting of the key was successful + * < 0 if an error occurred + */ int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key, unsigned int keylen); + +/** + * This function is a "short-hand" for the function calls of + * crypto_ahash_update and crypto_shash_final. The parameters have the same + * meaning as discussed for those separate functions. + * + * return value: + * 0 if the message digest creation was successful + * < 0 if an error occurred + */ int crypto_ahash_finup(struct ahash_request *req); + +/** + * 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 registered with the ahash_request handle. + * + * @req reference to the ahash_request handle that holds all information + * needed to perform the cipher operation + * + * return value: + * 0 if the message digest creation was successful + * < 0 if an error occurred + */ int crypto_ahash_final(struct ahash_request *req); + +/** + * This function is a "short-hand" for the function calls of crypto_ahash_init, + * crypto_ahash_update and crypto_ahash_final. The parameters have the same + * meaning as discussed for those separate three functions. + * + * return value: + * 0 if the message digest creation was successful + * < 0 if an error occurred + */ int crypto_ahash_digest(struct ahash_request *req); +/** + * This function exports the hash state of the ahash_request handle into the + * caller-allocated output buffer out which must have sufficient size (e.g. by + * calling crypto_ahash_reqsize). + * + * @req reference to the ahash_request handle whose state is exported + * @out output buffer of sufficient size that can hold the hash state + * + * return value: + * 0 if the export was successful + * < 0 if an error occurred + */ static inline int crypto_ahash_export(struct ahash_request *req, void *out) { return crypto_ahash_reqtfm(req)->export(req, out); } +/** + * This function imports the hash state into the ahash_request handle from the + * input buffer. That buffer should have been generated with the + * crypto_ahash_export function. + * + * @req reference to ahash_request handle the state is imported into + * @in buffer holding the state + * + * return value: + * 0 if the import was successful + * < 0 if an error occurred + */ static inline int crypto_ahash_import(struct ahash_request *req, const void *in) { return crypto_ahash_reqtfm(req)->import(req, in); } +/** + * The call (re-)initializes the message digest referenced by the ahash_request + * handle. Any potentially existing state created by previous operations is + * discarded. + * + * @req ahash_request handle that already is initialized with all necessary + * data using the ahash_request_* API functions + * + * return value: + * 0 if the message digest initialization was successful + * < 0 if an error occurred + */ static inline int crypto_ahash_init(struct ahash_request *req) { return crypto_ahash_reqtfm(req)->init(req); } +/** + * Updates the message digest state of the ahash_request handle. The input data + * is pointed to by the scatter/gather list registered in the ahash_request + * handle + * + * @req ahash_request handle that was previously initialized with the + * crypto_ahash_init call. + * + * return value: + * 0 if the message digest update was successful + * < 0 if an error occurred + */ static inline int crypto_ahash_update(struct ahash_request *req) { return crypto_ahash_reqtfm(req)->update(req); } +/** + * Allow the caller to replace the existing ahash handle in the request + * data structure with a different one. + * + * @req request handle to be modified + * @tfm cipher handle that shall be added to the request handle + */ static inline void ahash_request_set_tfm(struct ahash_request *req, struct crypto_ahash *tfm) { req->base.tfm = crypto_ahash_tfm(tfm); } +/** + * The hash_request data structure contains all pointers to data + * required for the asynchronous cipher operation. This includes the cipher + * handle (which can be used by multiple ahash_request instances), pointer + * to plaintext and the message digest output buffer, asynchronous callback + * function, etc. It acts as a handle to the ahash_request_* API calls in a + * similar way as ahash handle to the crypto_ahash_* API calls. + */ + +/** + * Allocate the request data structure that must be used with the ahash + * message digest API calls. During the allocation, the provided ahash handle + * is registered in the request data structure. + * + * @tfm cipher handle to be registered with the request + * @gfp memory allocation flag that is handed to kmalloc by the API call. + * + * return value: + * allocated request handle in case of success + * IS_ERR() is true in case of an error, PTR_ERR() returns the error code. + */ static inline struct ahash_request *ahash_request_alloc( struct crypto_ahash *tfm, gfp_t gfp) { @@ -230,6 +413,11 @@ static inline struct ahash_request *ahash_request_alloc( return req; } +/** + * The referenced request data structure is zeroized and subsequently freed. + * + * @req request data structure cipher handle to be freed + */ static inline void ahash_request_free(struct ahash_request *req) { kzfree(req); @@ -241,6 +429,30 @@ static inline struct ahash_request *ahash_request_cast( return container_of(req, struct ahash_request, base); } +/** + * Setting the callback function that is triggered once the cipher operation + * completes + * + * The callback function is registered with the ahash_request handle and + * must comply with the following template: + * + * void callback_function(struct crypto_async_request *req, int error) + * + * @req request handle + * @flags specify zero or an ORing of the following flags: + * * CRYPTO_TFM_REQ_MAY_BACKLOG: the request queue may back log and + * increase the wait queue beyond the initial maximum size + * * CRYPTO_TFM_REQ_MAY_SLEEP: the request processing may sleep + * @compl callback function pointer to be registered with the request handle + * @data The data pointer refers to memory that is not used by the kernel + * crypto API, but provided to the callback function for it to use. Here, + * the caller can provide a reference to memory the callback function can + * operate on. As the callback function is invoked asynchronously to the + * related functionality, it may need to access data structures of the + * related functionality which can be referenced using this pointer. The + * callback function can access the memory via the "data" field in the + * crypto_async_request data structure provided to the callback function. + */ static inline void ahash_request_set_callback(struct ahash_request *req, u32 flags, crypto_completion_t compl, @@ -251,6 +463,18 @@ static inline void ahash_request_set_callback(struct ahash_request *req, req->base.flags = flags; } +/** + * By using this call, the caller references the source scatter/gather list. + * The source scatter/gather list points to the data the message digest is to + * be calculated for. + * + * @req ahash_request handle to be updated + * @src source scatter/gather list + * @result buffer that is filled with the message digest -- the caller must + * ensure that the buffer has sufficient space by, for example, calling + * crypto_ahash_digestsize + * @nbytes number of bytes to process from the source scatter/gather list + */ static inline void ahash_request_set_crypt(struct ahash_request *req, struct scatterlist *src, u8 *result, unsigned int nbytes) -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/