crypto: skcipher - Add top-level skcipher interface (7a7ffe65) · Commits · 戴 / test

crypto/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -17,6 +17,7 @@ obj-$(CONFIG_CRYPTO_AEAD2) += aead.o

		crypto_blkcipher-y := ablkcipher.o
		crypto_blkcipher-y += blkcipher.o
		crypto_blkcipher-y += skcipher.o
		obj-$(CONFIG_CRYPTO_BLKCIPHER2) += crypto_blkcipher.o
		obj-$(CONFIG_CRYPTO_BLKCIPHER2) += chainiv.o
		obj-$(CONFIG_CRYPTO_BLKCIPHER2) += eseqiv.o

crypto/skcipher.c

0 → 100644

+245 −0

Original line number	Diff line number	Diff line
		/*
		* Symmetric key cipher operations.
		*
		* Generic encrypt/decrypt wrapper for ciphers, handles operations across
		* multiple page boundaries by using temporary blocks. In user context,
		* the kernel is given a chance to schedule us once per page.
		*
		* Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
		*
		* This program is free software; you can redistribute it and/or modify it
		* under the terms of the GNU General Public License as published by the Free
		* Software Foundation; either version 2 of the License, or (at your option)
		* any later version.
		*
		*/

		#include <crypto/internal/skcipher.h>
		#include <linux/bug.h>
		#include <linux/module.h>

		#include "internal.h"

		static unsigned int crypto_skcipher_extsize(struct crypto_alg *alg)
		{
		if (alg->cra_type == &crypto_blkcipher_type)
		return sizeof(struct crypto_blkcipher *);

		BUG_ON(alg->cra_type != &crypto_ablkcipher_type &&
		alg->cra_type != &crypto_givcipher_type);

		return sizeof(struct crypto_ablkcipher *);
		}

		static int skcipher_setkey_blkcipher(struct crypto_skcipher *tfm,
		const u8 *key, unsigned int keylen)
		{
		struct crypto_blkcipher **ctx = crypto_skcipher_ctx(tfm);
		struct crypto_blkcipher blkcipher = ctx;
		int err;

		crypto_blkcipher_clear_flags(blkcipher, ~0);
		crypto_blkcipher_set_flags(blkcipher, crypto_skcipher_get_flags(tfm) &
		CRYPTO_TFM_REQ_MASK);
		err = crypto_blkcipher_setkey(blkcipher, key, keylen);
		crypto_skcipher_set_flags(tfm, crypto_blkcipher_get_flags(blkcipher) &
		CRYPTO_TFM_RES_MASK);

		return err;
		}

		static int skcipher_crypt_blkcipher(struct skcipher_request *req,
		int (crypt)(struct blkcipher_desc ,
		struct scatterlist *,
		struct scatterlist *,
		unsigned int))
		{
		struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
		struct crypto_blkcipher **ctx = crypto_skcipher_ctx(tfm);
		struct blkcipher_desc desc = {
		.tfm = *ctx,
		.info = req->iv,
		.flags = req->base.flags,
		};


		return crypt(&desc, req->dst, req->src, req->cryptlen);
		}

		static int skcipher_encrypt_blkcipher(struct skcipher_request *req)
		{
		struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
		struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher);
		struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;

		return skcipher_crypt_blkcipher(req, alg->encrypt);
		}

		static int skcipher_decrypt_blkcipher(struct skcipher_request *req)
		{
		struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
		struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher);
		struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;

		return skcipher_crypt_blkcipher(req, alg->decrypt);
		}

		static void crypto_exit_skcipher_ops_blkcipher(struct crypto_tfm *tfm)
		{
		struct crypto_blkcipher **ctx = crypto_tfm_ctx(tfm);

		crypto_free_blkcipher(*ctx);
		}

		int crypto_init_skcipher_ops_blkcipher(struct crypto_tfm *tfm)
		{
		struct crypto_alg *calg = tfm->__crt_alg;
		struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm);
		struct crypto_blkcipher **ctx = crypto_tfm_ctx(tfm);
		struct crypto_blkcipher *blkcipher;
		struct crypto_tfm *btfm;

		if (!crypto_mod_get(calg))
		return -EAGAIN;

		btfm = __crypto_alloc_tfm(calg, CRYPTO_ALG_TYPE_BLKCIPHER,
		CRYPTO_ALG_TYPE_MASK);
		if (IS_ERR(btfm)) {
		crypto_mod_put(calg);
		return PTR_ERR(btfm);
		}

		blkcipher = __crypto_blkcipher_cast(btfm);
		*ctx = blkcipher;
		tfm->exit = crypto_exit_skcipher_ops_blkcipher;

		skcipher->setkey = skcipher_setkey_blkcipher;
		skcipher->encrypt = skcipher_encrypt_blkcipher;
		skcipher->decrypt = skcipher_decrypt_blkcipher;

		skcipher->ivsize = crypto_blkcipher_ivsize(blkcipher);

		return 0;
		}

		static int skcipher_setkey_ablkcipher(struct crypto_skcipher *tfm,
		const u8 *key, unsigned int keylen)
		{
		struct crypto_ablkcipher **ctx = crypto_skcipher_ctx(tfm);
		struct crypto_ablkcipher ablkcipher = ctx;
		int err;

		crypto_ablkcipher_clear_flags(ablkcipher, ~0);
		crypto_ablkcipher_set_flags(ablkcipher,
		crypto_skcipher_get_flags(tfm) &
		CRYPTO_TFM_REQ_MASK);
		err = crypto_ablkcipher_setkey(ablkcipher, key, keylen);
		crypto_skcipher_set_flags(tfm,
		crypto_ablkcipher_get_flags(ablkcipher) &
		CRYPTO_TFM_RES_MASK);

		return err;
		}

		static int skcipher_crypt_ablkcipher(struct skcipher_request *req,
		int (crypt)(struct ablkcipher_request ))
		{
		struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
		struct crypto_ablkcipher **ctx = crypto_skcipher_ctx(tfm);
		struct ablkcipher_request *subreq = skcipher_request_ctx(req);

		ablkcipher_request_set_tfm(subreq, *ctx);
		ablkcipher_request_set_callback(subreq, skcipher_request_flags(req),
		req->base.complete, req->base.data);
		ablkcipher_request_set_crypt(subreq, req->src, req->dst, req->cryptlen,
		req->iv);

		return crypt(subreq);
		}

		static int skcipher_encrypt_ablkcipher(struct skcipher_request *req)
		{
		struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
		struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher);
		struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;

		return skcipher_crypt_ablkcipher(req, alg->encrypt);
		}

		static int skcipher_decrypt_ablkcipher(struct skcipher_request *req)
		{
		struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
		struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher);
		struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;

		return skcipher_crypt_ablkcipher(req, alg->decrypt);
		}

		static void crypto_exit_skcipher_ops_ablkcipher(struct crypto_tfm *tfm)
		{
		struct crypto_ablkcipher **ctx = crypto_tfm_ctx(tfm);

		crypto_free_ablkcipher(*ctx);
		}

		int crypto_init_skcipher_ops_ablkcipher(struct crypto_tfm *tfm)
		{
		struct crypto_alg *calg = tfm->__crt_alg;
		struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm);
		struct crypto_ablkcipher **ctx = crypto_tfm_ctx(tfm);
		struct crypto_ablkcipher *ablkcipher;
		struct crypto_tfm *abtfm;

		if (!crypto_mod_get(calg))
		return -EAGAIN;

		abtfm = __crypto_alloc_tfm(calg, 0, 0);
		if (IS_ERR(abtfm)) {
		crypto_mod_put(calg);
		return PTR_ERR(abtfm);
		}

		ablkcipher = __crypto_ablkcipher_cast(abtfm);
		*ctx = ablkcipher;
		tfm->exit = crypto_exit_skcipher_ops_ablkcipher;

		skcipher->setkey = skcipher_setkey_ablkcipher;
		skcipher->encrypt = skcipher_encrypt_ablkcipher;
		skcipher->decrypt = skcipher_decrypt_ablkcipher;

		skcipher->ivsize = crypto_ablkcipher_ivsize(ablkcipher);
		skcipher->reqsize = crypto_ablkcipher_reqsize(ablkcipher) +
		sizeof(struct ablkcipher_request);

		return 0;
		}

		static int crypto_skcipher_init_tfm(struct crypto_tfm *tfm)
		{
		if (tfm->__crt_alg->cra_type == &crypto_blkcipher_type)
		return crypto_init_skcipher_ops_blkcipher(tfm);

		BUG_ON(tfm->__crt_alg->cra_type != &crypto_ablkcipher_type &&
		tfm->__crt_alg->cra_type != &crypto_givcipher_type);

		return crypto_init_skcipher_ops_ablkcipher(tfm);
		}

		static const struct crypto_type crypto_skcipher_type2 = {
		.extsize = crypto_skcipher_extsize,
		.init_tfm = crypto_skcipher_init_tfm,
		.maskclear = ~CRYPTO_ALG_TYPE_MASK,
		.maskset = CRYPTO_ALG_TYPE_BLKCIPHER_MASK,
		.type = CRYPTO_ALG_TYPE_BLKCIPHER,
		.tfmsize = offsetof(struct crypto_skcipher, base),
		};

		struct crypto_skcipher crypto_alloc_skcipher(const char alg_name,
		u32 type, u32 mask)
		{
		return crypto_alloc_tfm(alg_name, &crypto_skcipher_type2, type, mask);
		}
		EXPORT_SYMBOL_GPL(crypto_alloc_skcipher);

		MODULE_LICENSE("GPL");
		MODULE_DESCRIPTION("Symmetric key cipher type");

include/crypto/internal/skcipher.h

+15 −0

Original line number	Diff line number	Diff line
		@@ -107,5 +107,20 @@ static inline u32 ablkcipher_request_flags(struct ablkcipher_request *req)
		return req->base.flags;
		}

		static inline void crypto_skcipher_ctx(struct crypto_skcipher tfm)
		{
		return crypto_tfm_ctx(&tfm->base);
		}

		static inline void skcipher_request_ctx(struct skcipher_request req)
		{
		return req->__ctx;
		}

		static inline u32 skcipher_request_flags(struct skcipher_request *req)
		{
		return req->base.flags;
		}

		#endif /* _CRYPTO_INTERNAL_SKCIPHER_H */

include/crypto/skcipher.h

+390 −1

Original line number	Diff line number	Diff line
		/*
		* Symmetric key ciphers.
		*
		* Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
		* Copyright (c) 2007-2015 Herbert Xu <herbert@gondor.apana.org.au>
		*
		* This program is free software; you can redistribute it and/or modify it
		* under the terms of the GNU General Public License as published by the Free
		@@ -17,6 +17,28 @@
		#include <linux/kernel.h>
		#include <linux/slab.h>

		/**
		* struct skcipher_request - Symmetric key cipher request
		* @cryptlen: Number of bytes to encrypt or decrypt
		* @iv: Initialisation Vector
		* @src: Source SG list
		* @dst: Destination SG list
		* @base: Underlying async request request
		* @__ctx: Start of private context data
		*/
		struct skcipher_request {
		unsigned int cryptlen;

		u8 *iv;

		struct scatterlist *src;
		struct scatterlist *dst;

		struct crypto_async_request base;

		void *__ctx[] CRYPTO_MINALIGN_ATTR;
		};

		/**
		* struct skcipher_givcrypt_request - Crypto request with IV generation
		* @seq: Sequence number for IV generation
		@@ -30,6 +52,23 @@ struct skcipher_givcrypt_request {
		struct ablkcipher_request creq;
		};

		struct crypto_skcipher {
		int (setkey)(struct crypto_skcipher tfm, const u8 *key,
		unsigned int keylen);
		int (encrypt)(struct skcipher_request req);
		int (decrypt)(struct skcipher_request req);

		unsigned int ivsize;
		unsigned int reqsize;

		struct crypto_tfm base;
		};

		#define SKCIPHER_REQUEST_ON_STACK(name, tfm) \
		char __##name##_desc[sizeof(struct skcipher_request) + \
		crypto_skcipher_reqsize(tfm)] CRYPTO_MINALIGN_ATTR; \
		struct skcipher_request name = (void )__##name##_desc

		static inline struct crypto_ablkcipher *skcipher_givcrypt_reqtfm(
		struct skcipher_givcrypt_request *req)
		{
		@@ -106,5 +145,355 @@ static inline void skcipher_givcrypt_set_giv(
		req->seq = seq;
		}

		/**
		* DOC: Symmetric Key Cipher API
		*
		* Symmetric key cipher API is used with the ciphers of type
		* CRYPTO_ALG_TYPE_SKCIPHER (listed as type "skcipher" in /proc/crypto).
		*
		* Asynchronous cipher operations imply that the function invocation for a
		* cipher request returns immediately before the completion of the operation.
		* The cipher request is scheduled as a separate kernel thread and therefore
		* load-balanced on the different CPUs via the process scheduler. To allow
		* the kernel crypto API to inform the caller about the completion of a cipher
		* request, the caller must provide a callback function. That function is
		* invoked with the cipher handle when the request completes.
		*
		* To support the asynchronous operation, additional information than just the
		* cipher handle must be supplied to the kernel crypto API. That additional
		* information is given by filling in the skcipher_request data structure.
		*
		* For the symmetric key cipher API, the state is maintained with the tfm
		* cipher handle. A single tfm can be used across multiple calls and in
		* parallel. For asynchronous block cipher calls, context data supplied and
		* only used by the caller can be referenced the request data structure in
		* addition to the IV used for the cipher request. The maintenance of such
		* state information would be important for a crypto driver implementer to
		* have, because when calling the callback function upon completion of the
		* cipher operation, that callback function may need some information about
		* which operation just finished if it invoked multiple in parallel. This
		* state information is unused by the kernel crypto API.
		*/

		static inline struct crypto_skcipher *__crypto_skcipher_cast(
		struct crypto_tfm *tfm)
		{
		return container_of(tfm, struct crypto_skcipher, base);
		}

		/**
		* crypto_alloc_skcipher() - allocate symmetric key cipher handle
		* @alg_name: is the cra_name / name or cra_driver_name / driver name of the
		* skcipher cipher
		* @type: specifies the type of the cipher
		* @mask: specifies the mask for the cipher
		*
		* Allocate a cipher handle for an skcipher. The returned struct
		* crypto_skcipher is the cipher handle that is required for any subsequent
		* API invocation for that skcipher.
		*
		* 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_skcipher crypto_alloc_skcipher(const char alg_name,
		u32 type, u32 mask);

		static inline struct crypto_tfm *crypto_skcipher_tfm(
		struct crypto_skcipher *tfm)
		{
		return &tfm->base;
		}

		/**
		* crypto_free_skcipher() - zeroize and free cipher handle
		* @tfm: cipher handle to be freed
		*/
		static inline void crypto_free_skcipher(struct crypto_skcipher *tfm)
		{
		crypto_destroy_tfm(tfm, crypto_skcipher_tfm(tfm));
		}

		/**
		* crypto_has_skcipher() - Search for the availability of an skcipher.
		* @alg_name: is the cra_name / name or cra_driver_name / driver name of the
		* skcipher
		* @type: specifies the type of the cipher
		* @mask: specifies the mask for the cipher
		*
		* Return: true when the skcipher is known to the kernel crypto API; false
		* otherwise
		*/
		static inline int crypto_has_skcipher(const char *alg_name, u32 type,
		u32 mask)
		{
		return crypto_has_alg(alg_name, crypto_skcipher_type(type),
		crypto_skcipher_mask(mask));
		}

		/**
		* crypto_skcipher_ivsize() - obtain IV size
		* @tfm: cipher handle
		*
		* The size of the IV for the skcipher referenced by the cipher handle is
		* returned. This IV size may be zero if the cipher does not need an IV.
		*
		* Return: IV size in bytes
		*/
		static inline unsigned int crypto_skcipher_ivsize(struct crypto_skcipher *tfm)
		{
		return tfm->ivsize;
		}

		/**
		* crypto_skcipher_blocksize() - obtain block size of cipher
		* @tfm: cipher handle
		*
		* The block size for the skcipher referenced with the cipher handle is
		* returned. The caller may use that information to allocate appropriate
		* memory for the data returned by the encryption or decryption operation
		*
		* Return: block size of cipher
		*/
		static inline unsigned int crypto_skcipher_blocksize(
		struct crypto_skcipher *tfm)
		{
		return crypto_tfm_alg_blocksize(crypto_skcipher_tfm(tfm));
		}

		static inline unsigned int crypto_skcipher_alignmask(
		struct crypto_skcipher *tfm)
		{
		return crypto_tfm_alg_alignmask(crypto_skcipher_tfm(tfm));
		}

		static inline u32 crypto_skcipher_get_flags(struct crypto_skcipher *tfm)
		{
		return crypto_tfm_get_flags(crypto_skcipher_tfm(tfm));
		}

		static inline void crypto_skcipher_set_flags(struct crypto_skcipher *tfm,
		u32 flags)
		{
		crypto_tfm_set_flags(crypto_skcipher_tfm(tfm), flags);
		}

		static inline void crypto_skcipher_clear_flags(struct crypto_skcipher *tfm,
		u32 flags)
		{
		crypto_tfm_clear_flags(crypto_skcipher_tfm(tfm), flags);
		}

		/**
		* crypto_skcipher_setkey() - set key for cipher
		* @tfm: cipher handle
		* @key: buffer holding the key
		* @keylen: length of the key in bytes
		*
		* The caller provided key is set for the skcipher referenced by the cipher
		* handle.
		*
		* Note, the key length determines the cipher type. Many block ciphers implement
		* different cipher modes depending on the key size, such as AES-128 vs AES-192
		* vs. AES-256. When providing a 16 byte key for an AES cipher handle, AES-128
		* is performed.
		*
		* Return: 0 if the setting of the key was successful; < 0 if an error occurred
		*/
		static inline int crypto_skcipher_setkey(struct crypto_skcipher *tfm,
		const u8 *key, unsigned int keylen)
		{
		return tfm->setkey(tfm, key, keylen);
		}

		/**
		* crypto_skcipher_reqtfm() - obtain cipher handle from request
		* @req: skcipher_request out of which the cipher handle is to be obtained
		*
		* Return the crypto_skcipher handle when furnishing an skcipher_request
		* data structure.
		*
		* Return: crypto_skcipher handle
		*/
		static inline struct crypto_skcipher *crypto_skcipher_reqtfm(
		struct skcipher_request *req)
		{
		return __crypto_skcipher_cast(req->base.tfm);
		}

		/**
		* crypto_skcipher_encrypt() - encrypt plaintext
		* @req: reference to the skcipher_request handle that holds all information
		* needed to perform the cipher operation
		*
		* Encrypt plaintext data using the skcipher_request handle. That data
		* structure and how it is filled with data is discussed with the
		* skcipher_request_* functions.
		*
		* Return: 0 if the cipher operation was successful; < 0 if an error occurred
		*/
		static inline int crypto_skcipher_encrypt(struct skcipher_request *req)
		{
		struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);

		return tfm->encrypt(req);
		}

		/**
		* crypto_skcipher_decrypt() - decrypt ciphertext
		* @req: reference to the skcipher_request handle that holds all information
		* needed to perform the cipher operation
		*
		* Decrypt ciphertext data using the skcipher_request handle. That data
		* structure and how it is filled with data is discussed with the
		* skcipher_request_* functions.
		*
		* Return: 0 if the cipher operation was successful; < 0 if an error occurred
		*/
		static inline int crypto_skcipher_decrypt(struct skcipher_request *req)
		{
		struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);

		return tfm->decrypt(req);
		}

		/**
		* DOC: Symmetric Key Cipher Request Handle
		*
		* The skcipher_request data structure contains all pointers to data
		* required for the symmetric key cipher operation. This includes the cipher
		* handle (which can be used by multiple skcipher_request instances), pointer
		* to plaintext and ciphertext, asynchronous callback function, etc. It acts
		* as a handle to the skcipher_request_* API calls in a similar way as
		* skcipher handle to the crypto_skcipher_* API calls.
		*/

		/**
		* crypto_skcipher_reqsize() - obtain size of the request data structure
		* @tfm: cipher handle
		*
		* Return: number of bytes
		*/
		static inline unsigned int crypto_skcipher_reqsize(struct crypto_skcipher *tfm)
		{
		return tfm->reqsize;
		}

		/**
		* skcipher_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 skcipher handle in the request
		* data structure with a different one.
		*/
		static inline void skcipher_request_set_tfm(struct skcipher_request *req,
		struct crypto_skcipher *tfm)
		{
		req->base.tfm = crypto_skcipher_tfm(tfm);
		}

		static inline struct skcipher_request *skcipher_request_cast(
		struct crypto_async_request *req)
		{
		return container_of(req, struct skcipher_request, base);
		}

		/**
		* skcipher_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 skcipher
		* encrypt and decrypt API calls. During the allocation, the provided skcipher
		* 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 skcipher_request *skcipher_request_alloc(
		struct crypto_skcipher *tfm, gfp_t gfp)
		{
		struct skcipher_request *req;

		req = kmalloc(sizeof(struct skcipher_request) +
		crypto_skcipher_reqsize(tfm), gfp);

		if (likely(req))
		skcipher_request_set_tfm(req, tfm);

		return req;
		}

		/**
		* skcipher_request_free() - zeroize and free request data structure
		* @req: request data structure cipher handle to be freed
		*/
		static inline void skcipher_request_free(struct skcipher_request *req)
		{
		kzfree(req);
		}

		/**
		* skcipher_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 skcipher_request handle and
		* must comply with the following template
		*
		* void callback_function(struct crypto_async_request *req, int error)
		*/
		static inline void skcipher_request_set_callback(struct skcipher_request *req,
		u32 flags,
		crypto_completion_t compl,
		void *data)
		{
		req->base.complete = compl;
		req->base.data = data;
		req->base.flags = flags;
		}

		/**
		* skcipher_request_set_crypt() - set data buffers
		* @req: request handle
		* @src: source scatter / gather list
		* @dst: destination scatter / gather list
		* @cryptlen: number of bytes to process from @src
		* @iv: IV for the cipher operation which must comply with the IV size defined
		* by crypto_skcipher_ivsize
		*
		* This function allows setting of the source data and destination data
		* scatter / gather lists.
		*
		* For encryption, the source is treated as the plaintext and the
		* destination is the ciphertext. For a decryption operation, the use is
		* reversed - the source is the ciphertext and the destination is the plaintext.
		*/
		static inline void skcipher_request_set_crypt(
		struct skcipher_request *req,
		struct scatterlist src, struct scatterlist dst,
		unsigned int cryptlen, void *iv)
		{
		req->src = src;
		req->dst = dst;
		req->cryptlen = cryptlen;
		req->iv = iv;
		}

		#endif /* _CRYPTO_SKCIPHER_H */

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