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![Eric Biggers](/assets/img/avatar_default.png)
Similar to what was done for the hash API, update the skcipher API to track whether each transform has been keyed, and reject encryption/decryption if a key is needed but one hasn't been set. This isn't as important as the equivalent fix for the hash API because symmetric ciphers almost always require a key (the "null cipher" is the only exception), so are unlikely to be used without one. Still, tracking the key will prevent accidental unkeyed use. algif_skcipher also had to track the key anyway, so the new flag replaces that and simplifies the algif_skcipher implementation. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
613 lines
21 KiB
C
613 lines
21 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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/**
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* struct skcipher_alg - symmetric key cipher definition
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* @min_keysize: Minimum key size supported by the transformation. This is the
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* smallest key length supported by this transformation algorithm.
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* This must be set to one of the pre-defined values as this is
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* not hardware specific. Possible values for this field can be
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* found via git grep "_MIN_KEY_SIZE" include/crypto/
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* @max_keysize: Maximum key size supported by the transformation. This is the
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* largest key length supported by this transformation algorithm.
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* This must be set to one of the pre-defined values as this is
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* not hardware specific. Possible values for this field can be
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* found via git grep "_MAX_KEY_SIZE" include/crypto/
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* @setkey: Set key for the transformation. This function is used to either
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* program a supplied key into the hardware or store the key in the
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* transformation context for programming it later. Note that this
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* function does modify the transformation context. This function can
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* be called multiple times during the existence of the transformation
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* object, so one must make sure the key is properly reprogrammed into
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* the hardware. This function is also responsible for checking the key
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* length for validity. In case a software fallback was put in place in
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* the @cra_init call, this function might need to use the fallback if
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* the algorithm doesn't support all of the key sizes.
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* @encrypt: Encrypt a scatterlist of blocks. This function is used to encrypt
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* the supplied scatterlist containing the blocks of data. The crypto
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* API consumer is responsible for aligning the entries of the
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* scatterlist properly and making sure the chunks are correctly
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* sized. In case a software fallback was put in place in the
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* @cra_init call, this function might need to use the fallback if
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* the algorithm doesn't support all of the key sizes. In case the
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* key was stored in transformation context, the key might need to be
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* re-programmed into the hardware in this function. This function
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* shall not modify the transformation context, as this function may
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* be called in parallel with the same transformation object.
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* @decrypt: Decrypt a single block. This is a reverse counterpart to @encrypt
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* and the conditions are exactly the same.
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* @init: Initialize the cryptographic transformation object. This function
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* is used to initialize the cryptographic transformation object.
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* This function is called only once at the instantiation time, right
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* after the transformation context was allocated. In case the
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* cryptographic hardware has some special requirements which need to
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* be handled by software, this function shall check for the precise
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* requirement of the transformation and put any software fallbacks
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* in place.
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* @exit: Deinitialize the cryptographic transformation object. This is a
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* counterpart to @init, used to remove various changes set in
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* @init.
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* @ivsize: IV size applicable for transformation. The consumer must provide an
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* IV of exactly that size to perform the encrypt or decrypt operation.
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* @chunksize: Equal to the block size except for stream ciphers such as
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* CTR where it is set to the underlying block size.
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* @walksize: Equal to the chunk size except in cases where the algorithm is
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* considerably more efficient if it can operate on multiple chunks
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* in parallel. Should be a multiple of chunksize.
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* @base: Definition of a generic crypto algorithm.
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*
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* All fields except @ivsize are mandatory and must be filled.
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*/
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struct skcipher_alg {
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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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int (*init)(struct crypto_skcipher *tfm);
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void (*exit)(struct crypto_skcipher *tfm);
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unsigned int min_keysize;
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unsigned int max_keysize;
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unsigned int ivsize;
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unsigned int chunksize;
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unsigned int walksize;
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struct crypto_alg 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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/**
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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_has_skcipher2() - 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 skcipher
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* @mask: specifies the mask for the skcipher
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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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int crypto_has_skcipher2(const char *alg_name, u32 type, u32 mask);
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static inline const char *crypto_skcipher_driver_name(
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struct crypto_skcipher *tfm)
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{
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return crypto_tfm_alg_driver_name(crypto_skcipher_tfm(tfm));
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}
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static inline struct skcipher_alg *crypto_skcipher_alg(
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struct crypto_skcipher *tfm)
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{
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return container_of(crypto_skcipher_tfm(tfm)->__crt_alg,
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struct skcipher_alg, base);
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}
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static inline unsigned int crypto_skcipher_alg_ivsize(struct skcipher_alg *alg)
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{
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if ((alg->base.cra_flags & CRYPTO_ALG_TYPE_MASK) ==
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CRYPTO_ALG_TYPE_BLKCIPHER)
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return alg->base.cra_blkcipher.ivsize;
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if (alg->base.cra_ablkcipher.encrypt)
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return alg->base.cra_ablkcipher.ivsize;
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return alg->ivsize;
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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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static inline unsigned int crypto_skcipher_alg_chunksize(
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struct skcipher_alg *alg)
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{
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if ((alg->base.cra_flags & CRYPTO_ALG_TYPE_MASK) ==
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CRYPTO_ALG_TYPE_BLKCIPHER)
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return alg->base.cra_blocksize;
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if (alg->base.cra_ablkcipher.encrypt)
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return alg->base.cra_blocksize;
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return alg->chunksize;
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}
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static inline unsigned int crypto_skcipher_alg_walksize(
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struct skcipher_alg *alg)
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{
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if ((alg->base.cra_flags & CRYPTO_ALG_TYPE_MASK) ==
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CRYPTO_ALG_TYPE_BLKCIPHER)
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return alg->base.cra_blocksize;
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if (alg->base.cra_ablkcipher.encrypt)
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return alg->base.cra_blocksize;
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return alg->walksize;
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}
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/**
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* crypto_skcipher_chunksize() - obtain chunk size
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* @tfm: cipher handle
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*
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* The block size is set to one for ciphers such as CTR. However,
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* you still need to provide incremental updates in multiples of
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* the underlying block size as the IV does not have sub-block
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* granularity. This is known in this API as the chunk size.
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*
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* Return: chunk size in bytes
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*/
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static inline unsigned int crypto_skcipher_chunksize(
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struct crypto_skcipher *tfm)
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{
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return crypto_skcipher_alg_chunksize(crypto_skcipher_alg(tfm));
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}
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/**
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* crypto_skcipher_walksize() - obtain walk size
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* @tfm: cipher handle
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*
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* In some cases, algorithms can only perform optimally when operating on
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* multiple blocks in parallel. This is reflected by the walksize, which
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* must be a multiple of the chunksize (or equal if the concern does not
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* apply)
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*
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* Return: walk size in bytes
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*/
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static inline unsigned int crypto_skcipher_walksize(
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struct crypto_skcipher *tfm)
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{
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return crypto_skcipher_alg_walksize(crypto_skcipher_alg(tfm));
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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 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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if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
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return -ENOKEY;
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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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if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
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return -ENOKEY;
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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
|
|
* 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, or NULL if out of memory
|
|
*/
|
|
static inline struct skcipher_request *skcipher_request_alloc(
|
|
struct crypto_skcipher *tfm, gfp_t gfp)
|
|
{
|
|
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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|
|
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if (likely(req))
|
|
skcipher_request_set_tfm(req, tfm);
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|
|
|
return req;
|
|
}
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|
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|
/**
|
|
* 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);
|
|
}
|
|
|
|
static inline void skcipher_request_zero(struct skcipher_request *req)
|
|
{
|
|
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
|
|
|
|
memzero_explicit(req, sizeof(*req) + crypto_skcipher_reqsize(tfm));
|
|
}
|
|
|
|
/**
|
|
* 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 */
|
|
|