519 lines
16 KiB
C
519 lines
16 KiB
C
/*
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* Symmetric key ciphers.
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*
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* Copyright (c) 2007-2015 Herbert Xu <herbert@gondor.apana.org.au>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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*/
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#ifndef _CRYPTO_SKCIPHER_H
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#define _CRYPTO_SKCIPHER_H
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#include <linux/crypto.h>
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#include <linux/kernel.h>
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#include <linux/slab.h>
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/**
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* struct skcipher_request - Symmetric key cipher request
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* @cryptlen: Number of bytes to encrypt or decrypt
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* @iv: Initialisation Vector
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* @src: Source SG list
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* @dst: Destination SG list
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* @base: Underlying async request request
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* @__ctx: Start of private context data
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*/
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struct skcipher_request {
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unsigned int cryptlen;
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u8 *iv;
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struct scatterlist *src;
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struct scatterlist *dst;
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struct crypto_async_request base;
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void *__ctx[] CRYPTO_MINALIGN_ATTR;
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};
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/**
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* struct skcipher_givcrypt_request - Crypto request with IV generation
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* @seq: Sequence number for IV generation
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* @giv: Space for generated IV
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* @creq: The crypto request itself
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*/
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struct skcipher_givcrypt_request {
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u64 seq;
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u8 *giv;
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struct ablkcipher_request creq;
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};
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struct crypto_skcipher {
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int (*setkey)(struct crypto_skcipher *tfm, const u8 *key,
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unsigned int keylen);
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int (*encrypt)(struct skcipher_request *req);
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int (*decrypt)(struct skcipher_request *req);
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unsigned int ivsize;
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unsigned int reqsize;
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unsigned int keysize;
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struct crypto_tfm base;
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};
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#define SKCIPHER_REQUEST_ON_STACK(name, tfm) \
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char __##name##_desc[sizeof(struct skcipher_request) + \
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crypto_skcipher_reqsize(tfm)] CRYPTO_MINALIGN_ATTR; \
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struct skcipher_request *name = (void *)__##name##_desc
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static inline struct crypto_ablkcipher *skcipher_givcrypt_reqtfm(
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struct skcipher_givcrypt_request *req)
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{
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return crypto_ablkcipher_reqtfm(&req->creq);
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}
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static inline int crypto_skcipher_givencrypt(
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struct skcipher_givcrypt_request *req)
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{
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struct ablkcipher_tfm *crt =
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crypto_ablkcipher_crt(skcipher_givcrypt_reqtfm(req));
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return crt->givencrypt(req);
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};
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static inline int crypto_skcipher_givdecrypt(
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struct skcipher_givcrypt_request *req)
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{
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struct ablkcipher_tfm *crt =
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crypto_ablkcipher_crt(skcipher_givcrypt_reqtfm(req));
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return crt->givdecrypt(req);
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};
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static inline void skcipher_givcrypt_set_tfm(
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struct skcipher_givcrypt_request *req, struct crypto_ablkcipher *tfm)
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{
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req->creq.base.tfm = crypto_ablkcipher_tfm(tfm);
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}
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static inline struct skcipher_givcrypt_request *skcipher_givcrypt_cast(
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struct crypto_async_request *req)
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{
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return container_of(ablkcipher_request_cast(req),
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struct skcipher_givcrypt_request, creq);
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}
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static inline struct skcipher_givcrypt_request *skcipher_givcrypt_alloc(
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struct crypto_ablkcipher *tfm, gfp_t gfp)
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{
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struct skcipher_givcrypt_request *req;
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req = kmalloc(sizeof(struct skcipher_givcrypt_request) +
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crypto_ablkcipher_reqsize(tfm), gfp);
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if (likely(req))
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skcipher_givcrypt_set_tfm(req, tfm);
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return req;
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}
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static inline void skcipher_givcrypt_free(struct skcipher_givcrypt_request *req)
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{
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kfree(req);
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}
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static inline void skcipher_givcrypt_set_callback(
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struct skcipher_givcrypt_request *req, u32 flags,
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crypto_completion_t compl, void *data)
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{
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ablkcipher_request_set_callback(&req->creq, flags, compl, data);
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}
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static inline void skcipher_givcrypt_set_crypt(
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struct skcipher_givcrypt_request *req,
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struct scatterlist *src, struct scatterlist *dst,
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unsigned int nbytes, void *iv)
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{
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ablkcipher_request_set_crypt(&req->creq, src, dst, nbytes, iv);
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}
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static inline void skcipher_givcrypt_set_giv(
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struct skcipher_givcrypt_request *req, u8 *giv, u64 seq)
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{
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req->giv = giv;
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req->seq = seq;
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}
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/**
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* DOC: Symmetric Key Cipher API
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*
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* Symmetric key cipher API is used with the ciphers of type
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* CRYPTO_ALG_TYPE_SKCIPHER (listed as type "skcipher" in /proc/crypto).
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*
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* Asynchronous cipher operations imply that the function invocation for a
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* cipher request returns immediately before the completion of the operation.
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* The cipher request is scheduled as a separate kernel thread and therefore
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* load-balanced on the different CPUs via the process scheduler. To allow
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* the kernel crypto API to inform the caller about the completion of a cipher
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* request, the caller must provide a callback function. That function is
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* invoked with the cipher handle when the request completes.
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*
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* To support the asynchronous operation, additional information than just the
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* cipher handle must be supplied to the kernel crypto API. That additional
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* information is given by filling in the skcipher_request data structure.
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*
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* For the symmetric key cipher API, the state is maintained with the tfm
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* cipher handle. A single tfm can be used across multiple calls and in
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* parallel. For asynchronous block cipher calls, context data supplied and
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* only used by the caller can be referenced the request data structure in
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* addition to the IV used for the cipher request. The maintenance of such
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* state information would be important for a crypto driver implementer to
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* have, because when calling the callback function upon completion of the
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* cipher operation, that callback function may need some information about
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* which operation just finished if it invoked multiple in parallel. This
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* state information is unused by the kernel crypto API.
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*/
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static inline struct crypto_skcipher *__crypto_skcipher_cast(
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struct crypto_tfm *tfm)
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{
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return container_of(tfm, struct crypto_skcipher, base);
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}
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/**
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* crypto_alloc_skcipher() - allocate symmetric key cipher handle
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* @alg_name: is the cra_name / name or cra_driver_name / driver name of the
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* skcipher cipher
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* @type: specifies the type of the cipher
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* @mask: specifies the mask for the cipher
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*
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* Allocate a cipher handle for an skcipher. The returned struct
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* crypto_skcipher is the cipher handle that is required for any subsequent
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* API invocation for that skcipher.
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*
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* Return: allocated cipher handle in case of success; IS_ERR() is true in case
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* of an error, PTR_ERR() returns the error code.
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*/
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struct crypto_skcipher *crypto_alloc_skcipher(const char *alg_name,
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u32 type, u32 mask);
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static inline struct crypto_tfm *crypto_skcipher_tfm(
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struct crypto_skcipher *tfm)
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{
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return &tfm->base;
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}
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/**
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* crypto_free_skcipher() - zeroize and free cipher handle
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* @tfm: cipher handle to be freed
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*/
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static inline void crypto_free_skcipher(struct crypto_skcipher *tfm)
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{
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crypto_destroy_tfm(tfm, crypto_skcipher_tfm(tfm));
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}
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/**
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* crypto_has_skcipher() - Search for the availability of an skcipher.
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* @alg_name: is the cra_name / name or cra_driver_name / driver name of the
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* skcipher
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* @type: specifies the type of the cipher
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* @mask: specifies the mask for the cipher
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*
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* Return: true when the skcipher is known to the kernel crypto API; false
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* otherwise
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*/
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static inline int crypto_has_skcipher(const char *alg_name, u32 type,
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u32 mask)
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{
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return crypto_has_alg(alg_name, crypto_skcipher_type(type),
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crypto_skcipher_mask(mask));
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}
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/**
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* crypto_skcipher_ivsize() - obtain IV size
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* @tfm: cipher handle
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*
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* The size of the IV for the skcipher referenced by the cipher handle is
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* returned. This IV size may be zero if the cipher does not need an IV.
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*
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* Return: IV size in bytes
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*/
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static inline unsigned int crypto_skcipher_ivsize(struct crypto_skcipher *tfm)
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{
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return tfm->ivsize;
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}
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/**
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* crypto_skcipher_blocksize() - obtain block size of cipher
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* @tfm: cipher handle
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*
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* The block size for the skcipher referenced with the cipher handle is
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* returned. The caller may use that information to allocate appropriate
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* memory for the data returned by the encryption or decryption operation
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*
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* Return: block size of cipher
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*/
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static inline unsigned int crypto_skcipher_blocksize(
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struct crypto_skcipher *tfm)
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{
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return crypto_tfm_alg_blocksize(crypto_skcipher_tfm(tfm));
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}
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static inline unsigned int crypto_skcipher_alignmask(
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struct crypto_skcipher *tfm)
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{
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return crypto_tfm_alg_alignmask(crypto_skcipher_tfm(tfm));
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}
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static inline u32 crypto_skcipher_get_flags(struct crypto_skcipher *tfm)
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{
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return crypto_tfm_get_flags(crypto_skcipher_tfm(tfm));
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}
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static inline void crypto_skcipher_set_flags(struct crypto_skcipher *tfm,
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u32 flags)
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{
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crypto_tfm_set_flags(crypto_skcipher_tfm(tfm), flags);
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}
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static inline void crypto_skcipher_clear_flags(struct crypto_skcipher *tfm,
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u32 flags)
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{
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crypto_tfm_clear_flags(crypto_skcipher_tfm(tfm), flags);
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}
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/**
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* crypto_skcipher_setkey() - set key for cipher
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* @tfm: cipher handle
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* @key: buffer holding the key
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* @keylen: length of the key in bytes
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*
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* The caller provided key is set for the skcipher referenced by the cipher
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* handle.
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*
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* Note, the key length determines the cipher type. Many block ciphers implement
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* different cipher modes depending on the key size, such as AES-128 vs AES-192
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* vs. AES-256. When providing a 16 byte key for an AES cipher handle, AES-128
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* is performed.
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*
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* Return: 0 if the setting of the key was successful; < 0 if an error occurred
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*/
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static inline int crypto_skcipher_setkey(struct crypto_skcipher *tfm,
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const u8 *key, unsigned int keylen)
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{
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return tfm->setkey(tfm, key, keylen);
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}
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static inline bool crypto_skcipher_has_setkey(struct crypto_skcipher *tfm)
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{
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return tfm->keysize;
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}
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static inline unsigned int crypto_skcipher_default_keysize(
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struct crypto_skcipher *tfm)
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{
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return tfm->keysize;
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}
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/**
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* crypto_skcipher_reqtfm() - obtain cipher handle from request
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* @req: skcipher_request out of which the cipher handle is to be obtained
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*
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* Return the crypto_skcipher handle when furnishing an skcipher_request
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* data structure.
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*
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* Return: crypto_skcipher handle
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*/
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static inline struct crypto_skcipher *crypto_skcipher_reqtfm(
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struct skcipher_request *req)
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{
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return __crypto_skcipher_cast(req->base.tfm);
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}
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/**
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* crypto_skcipher_encrypt() - encrypt plaintext
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* @req: reference to the skcipher_request handle that holds all information
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* needed to perform the cipher operation
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*
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* Encrypt plaintext data using the skcipher_request handle. That data
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* structure and how it is filled with data is discussed with the
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* skcipher_request_* functions.
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*
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* Return: 0 if the cipher operation was successful; < 0 if an error occurred
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*/
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static inline int crypto_skcipher_encrypt(struct skcipher_request *req)
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{
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struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
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return tfm->encrypt(req);
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}
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/**
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* crypto_skcipher_decrypt() - decrypt ciphertext
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* @req: reference to the skcipher_request handle that holds all information
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* needed to perform the cipher operation
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*
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* Decrypt ciphertext data using the skcipher_request handle. That data
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* structure and how it is filled with data is discussed with the
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* skcipher_request_* functions.
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*
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* Return: 0 if the cipher operation was successful; < 0 if an error occurred
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*/
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static inline int crypto_skcipher_decrypt(struct skcipher_request *req)
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{
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struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
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return tfm->decrypt(req);
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}
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/**
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* DOC: Symmetric Key Cipher Request Handle
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*
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* The skcipher_request data structure contains all pointers to data
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* required for the symmetric key cipher operation. This includes the cipher
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* handle (which can be used by multiple skcipher_request instances), pointer
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* to plaintext and ciphertext, asynchronous callback function, etc. It acts
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* as a handle to the skcipher_request_* API calls in a similar way as
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* skcipher handle to the crypto_skcipher_* API calls.
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*/
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/**
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* crypto_skcipher_reqsize() - obtain size of the request data structure
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* @tfm: cipher handle
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*
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* Return: number of bytes
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*/
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static inline unsigned int crypto_skcipher_reqsize(struct crypto_skcipher *tfm)
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{
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return tfm->reqsize;
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}
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/**
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* skcipher_request_set_tfm() - update cipher handle reference in request
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* @req: request handle to be modified
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* @tfm: cipher handle that shall be added to the request handle
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*
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* Allow the caller to replace the existing skcipher handle in the request
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* data structure with a different one.
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*/
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static inline void skcipher_request_set_tfm(struct skcipher_request *req,
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struct crypto_skcipher *tfm)
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{
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req->base.tfm = crypto_skcipher_tfm(tfm);
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}
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static inline struct skcipher_request *skcipher_request_cast(
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struct crypto_async_request *req)
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{
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return container_of(req, struct skcipher_request, base);
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}
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/**
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* skcipher_request_alloc() - allocate request data structure
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* @tfm: cipher handle to be registered with the request
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* @gfp: memory allocation flag that is handed to kmalloc by the API call.
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*
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* Allocate the request data structure that must be used with the skcipher
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* encrypt and decrypt API calls. During the allocation, the provided skcipher
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* handle is registered in the request data structure.
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*
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* Return: allocated request handle in case of success; IS_ERR() is true in case
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* of an error, PTR_ERR() returns the error code.
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*/
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static inline struct skcipher_request *skcipher_request_alloc(
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struct crypto_skcipher *tfm, gfp_t gfp)
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{
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struct skcipher_request *req;
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req = kmalloc(sizeof(struct skcipher_request) +
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crypto_skcipher_reqsize(tfm), gfp);
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if (likely(req))
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skcipher_request_set_tfm(req, tfm);
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return req;
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}
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/**
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* skcipher_request_free() - zeroize and free request data structure
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* @req: request data structure cipher handle to be freed
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*/
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static inline void skcipher_request_free(struct skcipher_request *req)
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{
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kzfree(req);
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}
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static inline void skcipher_request_zero(struct skcipher_request *req)
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{
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struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
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memzero_explicit(req, sizeof(*req) + crypto_skcipher_reqsize(tfm));
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}
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/**
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* skcipher_request_set_callback() - set asynchronous callback function
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* @req: request handle
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* @flags: specify zero or an ORing of the flags
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* CRYPTO_TFM_REQ_MAY_BACKLOG the request queue may back log and
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* increase the wait queue beyond the initial maximum size;
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* CRYPTO_TFM_REQ_MAY_SLEEP the request processing may sleep
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* @compl: callback function pointer to be registered with the request handle
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* @data: The data pointer refers to memory that is not used by the kernel
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* crypto API, but provided to the callback function for it to use. Here,
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* the caller can provide a reference to memory the callback function can
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* operate on. As the callback function is invoked asynchronously to the
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* related functionality, it may need to access data structures of the
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* related functionality which can be referenced using this pointer. The
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* callback function can access the memory via the "data" field in the
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* crypto_async_request data structure provided to the callback function.
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*
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* This function allows setting the callback function that is triggered once the
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* cipher operation completes.
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*
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* The callback function is registered with the skcipher_request handle and
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* must comply with the following template
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*
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* void callback_function(struct crypto_async_request *req, int error)
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*/
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static inline void skcipher_request_set_callback(struct skcipher_request *req,
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u32 flags,
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crypto_completion_t compl,
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void *data)
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{
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req->base.complete = compl;
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req->base.data = data;
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req->base.flags = flags;
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}
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/**
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* skcipher_request_set_crypt() - set data buffers
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* @req: request handle
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* @src: source scatter / gather list
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* @dst: destination scatter / gather list
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* @cryptlen: number of bytes to process from @src
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* @iv: IV for the cipher operation which must comply with the IV size defined
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* by crypto_skcipher_ivsize
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*
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* This function allows setting of the source data and destination data
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* scatter / gather lists.
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*
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* For encryption, the source is treated as the plaintext and the
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* destination is the ciphertext. For a decryption operation, the use is
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* reversed - the source is the ciphertext and the destination is the plaintext.
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*/
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static inline void skcipher_request_set_crypt(
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struct skcipher_request *req,
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struct scatterlist *src, struct scatterlist *dst,
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unsigned int cryptlen, void *iv)
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{
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req->src = src;
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req->dst = dst;
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req->cryptlen = cryptlen;
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req->iv = iv;
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}
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#endif /* _CRYPTO_SKCIPHER_H */
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