From 47ca5be9eb066befe284f4e03fc11f21b8321ddc Mon Sep 17 00:00:00 2001 From: Stephan Mueller Date: Wed, 12 Nov 2014 05:30:42 +0100 Subject: [PATCH] crypto: doc - HASH API documentation 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 Signed-off-by: Herbert Xu --- include/linux/crypto.h | 119 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 119 insertions(+) diff --git a/include/linux/crypto.h b/include/linux/crypto.h index 0f95a07aa4df..208a63290b23 100644 --- a/include/linux/crypto.h +++ b/include/linux/crypto.h @@ -2082,6 +2082,13 @@ static inline void crypto_cipher_decrypt_one(struct crypto_cipher *tfm, dst, src); } +/** + * DOC: Synchronous Message Digest API + * + * The synchronous message digest API is used with 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; @@ -2094,6 +2101,20 @@ static inline struct crypto_hash *crypto_hash_cast(struct crypto_tfm *tfm) return __crypto_hash_cast(tfm); } +/** + * crypto_alloc_hash() - allocate synchronous 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_hash 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. + */ static inline struct crypto_hash *crypto_alloc_hash(const char *alg_name, u32 type, u32 mask) { @@ -2110,11 +2131,25 @@ static inline struct crypto_tfm *crypto_hash_tfm(struct crypto_hash *tfm) return &tfm->base; } +/** + * crypto_free_hash() - zeroize and free message digest handle + * @tfm: cipher handle to be freed + */ static inline void crypto_free_hash(struct crypto_hash *tfm) { crypto_free_tfm(crypto_hash_tfm(tfm)); } +/** + * crypto_has_hash() - Search for the availability of a 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 + * @mask: specifies the mask for the cipher + * + * Return: 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; @@ -2130,6 +2165,15 @@ static inline struct hash_tfm *crypto_hash_crt(struct crypto_hash *tfm) return &crypto_hash_tfm(tfm)->crt_hash; } +/** + * crypto_hash_blocksize() - obtain block size for message digest + * @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_hash_blocksize(struct crypto_hash *tfm) { return crypto_tfm_alg_blocksize(crypto_hash_tfm(tfm)); @@ -2140,6 +2184,15 @@ static inline unsigned int crypto_hash_alignmask(struct crypto_hash *tfm) return crypto_tfm_alg_alignmask(crypto_hash_tfm(tfm)); } +/** + * crypto_hash_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: message digest size + */ static inline unsigned int crypto_hash_digestsize(struct crypto_hash *tfm) { return crypto_hash_crt(tfm)->digestsize; @@ -2160,11 +2213,38 @@ static inline void crypto_hash_clear_flags(struct crypto_hash *tfm, u32 flags) crypto_tfm_clear_flags(crypto_hash_tfm(tfm), flags); } +/** + * crypto_hash_init() - (re)initialize message digest handle + * @desc: cipher request handle that to be filled by caller -- + * desc.tfm is filled with the hash cipher handle; + * desc.flags is filled with either CRYPTO_TFM_REQ_MAY_SLEEP or 0. + * + * The call (re-)initializes the message digest referenced by the hash cipher + * request 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_hash_init(struct hash_desc *desc) { return crypto_hash_crt(desc->tfm)->init(desc); } +/** + * crypto_hash_update() - add data to message digest for processing + * @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 + * + * 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. + * + * Return: 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) @@ -2172,11 +2252,39 @@ static inline int crypto_hash_update(struct hash_desc *desc, return crypto_hash_crt(desc->tfm)->update(desc, sg, nbytes); } +/** + * crypto_hash_final() - calculate message digest + * @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). + * + * 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. + * + * Return: 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); } +/** + * crypto_hash_digest() - calculate message digest for a buffer + * @desc: see crypto_hash_final() + * @sg: see crypto_hash_update() + * @nbytes: see crypto_hash_update() + * @out: see crypto_hash_final() + * + * 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: 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) @@ -2184,6 +2292,17 @@ static inline int crypto_hash_digest(struct hash_desc *desc, return crypto_hash_crt(desc->tfm)->digest(desc, sg, nbytes, out); } +/** + * crypto_hash_setkey() - set key for message digest + * @hash: cipher handle + * @key: buffer holding the key + * @keylen: length of the key in bytes + * + * 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. + * + * Return: 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) { -- 2.30.2