From: Stephan Mueller Subject: [PATCH v2 11/11] crypto: Documentation - HASH API documentation Date: Sun, 02 Nov 2014 21:42:06 +0100 Message-ID: <1602710.mIQNeDGnzH@tachyon.chronox.de> References: <6375771.bx7QqLJLuR@tachyon.chronox.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Cc: "David S. Miller" , Marek Vasut , Jason Cooper , Grant Likely , Geert Uytterhoeven , Linux Kernel Developers List , linux-crypto@vger.kernel.org To: Herbert Xu Return-path: Received: from mail.eperm.de ([89.247.134.16]:54169 "EHLO mail.eperm.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752363AbaKBUne (ORCPT ); Sun, 2 Nov 2014 15:43:34 -0500 Received: from tachyon.chronox.de by mail.eperm.de with [XMail 1.27 ESMTP Server] id for from ; Sun, 2 Nov 2014 21:43:29 +0100 In-Reply-To: <6375771.bx7QqLJLuR@tachyon.chronox.de> Sender: linux-crypto-owner@vger.kernel.org List-ID: The API function calls exported by the kernel crypto API for message digests to be used by consumers are documented. Signed-off-by: Stephan Mueller CC: Marek Vasut --- include/linux/crypto.h | 117 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 117 insertions(+) diff --git a/include/linux/crypto.h b/include/linux/crypto.h index b2c3ebb..de44f2d 100644 --- a/include/linux/crypto.h +++ b/include/linux/crypto.h @@ -2190,6 +2190,11 @@ static inline void crypto_cipher_decrypt_one(struct crypto_cipher *tfm, dst, src); } +/** + * Synchronous message digest API to use the ciphers of type + * CRYPTO_ALG_TYPE_HASH (listed as type "hash" in /proc/crypto) + */ + static inline struct crypto_hash *__crypto_hash_cast(struct crypto_tfm *tfm) { return (struct crypto_hash *)tfm; @@ -2202,6 +2207,20 @@ static inline struct crypto_hash *crypto_hash_cast(struct crypto_tfm *tfm) return __crypto_hash_cast(tfm); } +/** + * Allocate a cipher handle for a message digest. The returned struct + * crypto_hash is the cipher handle that is required for any subsequent + * API invocation for that message digest. + * + * @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 (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. + */ static inline struct crypto_hash *crypto_alloc_hash(const char *alg_name, u32 type, u32 mask) { @@ -2218,11 +2237,29 @@ static inline struct crypto_tfm *crypto_hash_tfm(struct crypto_hash *tfm) return &tfm->base; } +/** + * The referenced message digest handle is zeroized and subsequently + * freed. + * + * @tfm cipher handle to be freed + */ static inline void crypto_free_hash(struct crypto_hash *tfm) { crypto_free_tfm(crypto_hash_tfm(tfm)); } +/** + * Lookup function to search for the availability of a message digest cipher. + * + * @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 (see Documentation/crypto/) + * @mask specifies the mask for the cipher (see Documentation/crypto/) + + * return value: + * true when the message digest cipher is known to the kernel crypto API. + * false otherwise + */ static inline int crypto_has_hash(const char *alg_name, u32 type, u32 mask) { type &= ~CRYPTO_ALG_TYPE_MASK; @@ -2238,6 +2275,15 @@ static inline struct hash_tfm *crypto_hash_crt(struct crypto_hash *tfm) return &crypto_hash_tfm(tfm)->crt_hash; } +/** + * The block size for 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_hash_blocksize(struct crypto_hash *tfm) { return crypto_tfm_alg_blocksize(crypto_hash_tfm(tfm)); @@ -2248,6 +2294,15 @@ static inline unsigned int crypto_hash_alignmask(struct crypto_hash *tfm) return crypto_tfm_alg_alignmask(crypto_hash_tfm(tfm)); } +/** + * 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_hash_digestsize(struct crypto_hash *tfm) { return crypto_hash_crt(tfm)->digestsize; @@ -2268,11 +2323,38 @@ static inline void crypto_hash_clear_flags(struct crypto_hash *tfm, u32 flags) crypto_tfm_clear_flags(crypto_hash_tfm(tfm), flags); } +/** + * The call (re-)initializes the message digest referenced by the hash cipher + * request handle. Any potentially existing state created by previous + * operations is discarded. + * + * @desc cipher request handle that to be filled by caller as follows: + * desc.tfm is filled with the hash cipher handle + * desc.flags is filled with either CRYPTO_TFM_REQ_MAY_SLEEP or 0 + * + * return value: + * 0 if the message digest initialization was successful + * < 0 if an error occurred + */ static inline int crypto_hash_init(struct hash_desc *desc) { return crypto_hash_crt(desc->tfm)->init(desc); } +/** + * Updates the message digest state of the cipher handle pointed to by the + * hash cipher request handle with the input data pointed to by the + * scatter/gather list. + * + * @desc cipher request handle + * @sg scatter / gather list pointing to the data to be added to the message + * digest + * @nbytes number of bytes to be processed from @sg + * + * return value: + * 0 if the message digest update was successful + * < 0 if an error occurred + */ static inline int crypto_hash_update(struct hash_desc *desc, struct scatterlist *sg, unsigned int nbytes) @@ -2280,11 +2362,34 @@ static inline int crypto_hash_update(struct hash_desc *desc, return crypto_hash_crt(desc->tfm)->update(desc, sg, nbytes); } +/** + * 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. + * + * @desc cipher request handle + * @out message digest output buffer -- The caller must ensure that the out + * buffer has a sufficient size (e.g. by using the crypto_hash_digestsize + * function). + * + * return value: + * 0 if the message digest creation was successful + * < 0 if an error occurred + */ static inline int crypto_hash_final(struct hash_desc *desc, u8 *out) { return crypto_hash_crt(desc->tfm)->final(desc, out); } +/** + * This function is a "short-hand" for the function calls of crypto_hash_init, + * crypto_hash_update and crypto_hash_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 + */ static inline int crypto_hash_digest(struct hash_desc *desc, struct scatterlist *sg, unsigned int nbytes, u8 *out) @@ -2292,6 +2397,18 @@ static inline int crypto_hash_digest(struct hash_desc *desc, return crypto_hash_crt(desc->tfm)->digest(desc, sg, nbytes, out); } +/** + * The caller provided key is set for the message digest 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 + */ static inline int crypto_hash_setkey(struct crypto_hash *hash, const u8 *key, unsigned int keylen) { -- 2.1.0