crypto: doc - AHASH API documentation (90240ffb) · Commits · git / linux-net

include/crypto/hash.h

+228 −0

Original line number	Diff line number	Diff line
		@@ -202,11 +202,35 @@ struct crypto_shash {
		struct crypto_tfm base;
		};

		/**
		* DOC: Asynchronous Message Digest API
		*
		* The asynchronous message digest API is used with 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.
		*/

		static inline struct crypto_ahash __crypto_ahash_cast(struct crypto_tfm tfm)
		{
		return container_of(tfm, struct crypto_ahash, base);
		}

		/**
		* crypto_alloc_ahash() - allocate ahash cipher handle
		* @alg_name: is the cra_name / name or cra_driver_name / driver name of the
		* ahash cipher
		* @type: specifies the type of the cipher
		* @mask: specifies the mask for the cipher
		*
		* 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.
		*
		* 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_ahash crypto_alloc_ahash(const char alg_name, u32 type,
		u32 mask);

		@@ -215,6 +239,10 @@ static inline struct crypto_tfm crypto_ahash_tfm(struct crypto_ahash tfm)
		return &tfm->base;
		}

		/**
		* crypto_free_ahash() - zeroize and free the ahash handle
		* @tfm: cipher handle to be freed
		*/
		static inline void crypto_free_ahash(struct crypto_ahash *tfm)
		{
		crypto_destroy_tfm(tfm, crypto_ahash_tfm(tfm));
		@@ -238,6 +266,16 @@ static inline struct hash_alg_common *crypto_hash_alg_common(
		return __crypto_hash_alg_common(crypto_ahash_tfm(tfm)->__crt_alg);
		}

		/**
		* crypto_ahash_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 of cipher
		*/
		static inline unsigned int crypto_ahash_digestsize(struct crypto_ahash *tfm)
		{
		return crypto_hash_alg_common(tfm)->digestsize;
		@@ -263,12 +301,32 @@ static inline void crypto_ahash_clear_flags(struct crypto_ahash *tfm, u32 flags)
		crypto_tfm_clear_flags(crypto_ahash_tfm(tfm), flags);
		}

		/**
		* crypto_ahash_reqtfm() - obtain cipher handle from request
		* @req: asynchronous request handle that contains the reference to the ahash
		* cipher handle
		*
		* Return the ahash cipher handle that is registered with the asynchronous
		* request handle ahash_request.
		*
		* Return: ahash cipher handle
		*/
		static inline struct crypto_ahash *crypto_ahash_reqtfm(
		struct ahash_request *req)
		{
		return __crypto_ahash_cast(req->base.tfm);
		}

		/**
		* crypto_ahash_reqsize() - obtain size of the request data structure
		* @tfm: cipher handle
		*
		* 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.
		*
		* Return: size of the ahash state
		*/
		static inline unsigned int crypto_ahash_reqsize(struct crypto_ahash *tfm)
		{
		return tfm->reqsize;
		@@ -279,38 +337,166 @@ static inline void ahash_request_ctx(struct ahash_request req)
		return req->__ctx;
		}

		/**
		* crypto_ahash_setkey - set key for cipher handle
		* @tfm: cipher handle
		* @key: buffer holding the key
		* @keylen: length of the key in bytes
		*
		* 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.
		*
		* Return: 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);

		/**
		* crypto_ahash_finup() - update and finalize message digest
		* @req: reference to the ahash_request handle that holds all information
		* needed to perform the cipher operation
		*
		* 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: 0 if the message digest creation was successful; < 0 if an error
		* occurred
		*/
		int crypto_ahash_finup(struct ahash_request *req);

		/**
		* crypto_ahash_final() - calculate message digest
		* @req: reference to the ahash_request handle that holds all information
		* needed to perform the cipher operation
		*
		* 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.
		*
		* Return: 0 if the message digest creation was successful; < 0 if an error
		* occurred
		*/
		int crypto_ahash_final(struct ahash_request *req);

		/**
		* crypto_ahash_digest() - calculate message digest for a buffer
		* @req: reference to the ahash_request handle that holds all information
		* needed to perform the cipher operation
		*
		* 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: 0 if the message digest creation was successful; < 0 if an error
		* occurred
		*/
		int crypto_ahash_digest(struct ahash_request *req);

		/**
		* crypto_ahash_export() - extract current message digest state
		* @req: reference to the ahash_request 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 ahash_request handle into the
		* caller-allocated output buffer out which must have sufficient size (e.g. by
		* calling crypto_ahash_reqsize).
		*
		* Return: 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);
		}

		/**
		* crypto_ahash_import() - import message digest state
		* @req: reference to ahash_request handle the state is imported into
		* @in: buffer holding the state
		*
		* 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.
		*
		* Return: 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);
		}

		/**
		* crypto_ahash_init() - (re)initialize message digest handle
		* @req: ahash_request handle that already is initialized with all necessary
		* data using the ahash_request_* API functions
		*
		* The call (re-)initializes the message digest referenced by the ahash_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_ahash_init(struct ahash_request *req)
		{
		return crypto_ahash_reqtfm(req)->init(req);
		}

		/**
		* crypto_ahash_update() - add data to message digest for processing
		* @req: ahash_request handle that was previously initialized with the
		* crypto_ahash_init call.
		*
		* 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
		*
		* Return: 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);
		}

		/**
		* DOC: Asynchronous Hash Request Handle
		*
		* The &ahash_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.
		*/

		/**
		* ahash_request_set_tfm() - update cipher handle reference in request
		* @req: request handle to be modified
		* @tfm: cipher handle that shall be added to the request handle
		*
		* Allow the caller to replace the existing ahash handle in the request
		* data structure with a different one.
		*/
		static inline void ahash_request_set_tfm(struct ahash_request *req,
		struct crypto_ahash *tfm)
		{
		req->base.tfm = crypto_ahash_tfm(tfm);
		}

		/**
		* ahash_request_alloc() - allocate 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.
		*
		* 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.
		*
		* Return: 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)
		{
		@@ -325,6 +511,10 @@ static inline struct ahash_request *ahash_request_alloc(
		return req;
		}

		/**
		* ahash_request_free() - zeroize and free the request data structure
		* @req: request data structure cipher handle to be freed
		*/
		static inline void ahash_request_free(struct ahash_request *req)
		{
		kzfree(req);
		@@ -336,6 +526,31 @@ static inline struct ahash_request *ahash_request_cast(
		return container_of(req, struct ahash_request, base);
		}

		/**
		* ahash_request_set_callback() - set asynchronous callback function
		* @req: request handle
		* @flags: specify zero or an ORing of the 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.
		*
		* This function allows 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)
		*/
		static inline void ahash_request_set_callback(struct ahash_request *req,
		u32 flags,
		crypto_completion_t compl,
		@@ -346,6 +561,19 @@ static inline void ahash_request_set_callback(struct ahash_request *req,
		req->base.flags = flags;
		}

		/**
		* ahash_request_set_crypt() - set data buffers
		* @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
		*
		* 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.
		*/
		static inline void ahash_request_set_crypt(struct ahash_request *req,
		struct scatterlist src, u8 result,
		unsigned int nbytes)