linux/include/crypto/skcipher.h
Ard Biesheuvel c821f6ab2e crypto: skcipher - introduce walksize attribute for SIMD algos
In some cases, SIMD algorithms can only perform optimally when
allowed to operate on multiple input blocks in parallel. This is
especially true for bit slicing algorithms, which typically take
the same amount of time processing a single block or 8 blocks in
parallel. However, other SIMD algorithms may benefit as well from
bigger strides.

So add a walksize attribute to the skcipher algorithm definition, and
wire it up to the skcipher walk API. To avoid confusion between the
skcipher and AEAD attributes, rename the skcipher_walk chunksize
attribute to 'stride', and set it from the walksize (in the skcipher
case) or from the chunksize (in the AEAD case).

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-12-30 19:52:47 +08:00

613 lines
21 KiB
C

/*
* Symmetric key ciphers.
*
* 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
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
*/
#ifndef _CRYPTO_SKCIPHER_H
#define _CRYPTO_SKCIPHER_H
#include <linux/crypto.h>
#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
* @giv: Space for generated IV
* @creq: The crypto request itself
*/
struct skcipher_givcrypt_request {
u64 seq;
u8 *giv;
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;
unsigned int keysize;
struct crypto_tfm base;
};
/**
* struct skcipher_alg - symmetric key cipher definition
* @min_keysize: Minimum key size supported by the transformation. This is the
* smallest key length supported by this transformation algorithm.
* This must be set to one of the pre-defined values as this is
* not hardware specific. Possible values for this field can be
* found via git grep "_MIN_KEY_SIZE" include/crypto/
* @max_keysize: Maximum key size supported by the transformation. This is the
* largest key length supported by this transformation algorithm.
* This must be set to one of the pre-defined values as this is
* not hardware specific. Possible values for this field can be
* found via git grep "_MAX_KEY_SIZE" include/crypto/
* @setkey: Set key for the transformation. This function is used to either
* program a supplied key into the hardware or store the key in the
* transformation context for programming it later. Note that this
* function does modify the transformation context. This function can
* be called multiple times during the existence of the transformation
* object, so one must make sure the key is properly reprogrammed into
* the hardware. This function is also responsible for checking the key
* length for validity. In case a software fallback was put in place in
* the @cra_init call, this function might need to use the fallback if
* the algorithm doesn't support all of the key sizes.
* @encrypt: Encrypt a scatterlist of blocks. This function is used to encrypt
* the supplied scatterlist containing the blocks of data. The crypto
* API consumer is responsible for aligning the entries of the
* scatterlist properly and making sure the chunks are correctly
* sized. In case a software fallback was put in place in the
* @cra_init call, this function might need to use the fallback if
* the algorithm doesn't support all of the key sizes. In case the
* key was stored in transformation context, the key might need to be
* re-programmed into the hardware in this function. This function
* shall not modify the transformation context, as this function may
* be called in parallel with the same transformation object.
* @decrypt: Decrypt a single block. This is a reverse counterpart to @encrypt
* and the conditions are exactly the same.
* @init: Initialize the cryptographic transformation object. This function
* is used to initialize the cryptographic transformation object.
* This function is called only once at the instantiation time, right
* after the transformation context was allocated. In case the
* cryptographic hardware has some special requirements which need to
* be handled by software, this function shall check for the precise
* requirement of the transformation and put any software fallbacks
* in place.
* @exit: Deinitialize the cryptographic transformation object. This is a
* counterpart to @init, used to remove various changes set in
* @init.
* @ivsize: IV size applicable for transformation. The consumer must provide an
* IV of exactly that size to perform the encrypt or decrypt operation.
* @chunksize: Equal to the block size except for stream ciphers such as
* CTR where it is set to the underlying block size.
* @walksize: Equal to the chunk size except in cases where the algorithm is
* considerably more efficient if it can operate on multiple chunks
* in parallel. Should be a multiple of chunksize.
* @base: Definition of a generic crypto algorithm.
*
* All fields except @ivsize are mandatory and must be filled.
*/
struct skcipher_alg {
int (*setkey)(struct crypto_skcipher *tfm, const u8 *key,
unsigned int keylen);
int (*encrypt)(struct skcipher_request *req);
int (*decrypt)(struct skcipher_request *req);
int (*init)(struct crypto_skcipher *tfm);
void (*exit)(struct crypto_skcipher *tfm);
unsigned int min_keysize;
unsigned int max_keysize;
unsigned int ivsize;
unsigned int chunksize;
unsigned int walksize;
struct crypto_alg 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
/**
* 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_has_skcipher2() - 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 skcipher
* @mask: specifies the mask for the skcipher
*
* Return: true when the skcipher is known to the kernel crypto API; false
* otherwise
*/
int crypto_has_skcipher2(const char *alg_name, u32 type, u32 mask);
static inline const char *crypto_skcipher_driver_name(
struct crypto_skcipher *tfm)
{
return crypto_tfm_alg_driver_name(crypto_skcipher_tfm(tfm));
}
static inline struct skcipher_alg *crypto_skcipher_alg(
struct crypto_skcipher *tfm)
{
return container_of(crypto_skcipher_tfm(tfm)->__crt_alg,
struct skcipher_alg, base);
}
static inline unsigned int crypto_skcipher_alg_ivsize(struct skcipher_alg *alg)
{
if ((alg->base.cra_flags & CRYPTO_ALG_TYPE_MASK) ==
CRYPTO_ALG_TYPE_BLKCIPHER)
return alg->base.cra_blkcipher.ivsize;
if (alg->base.cra_ablkcipher.encrypt)
return alg->base.cra_ablkcipher.ivsize;
return alg->ivsize;
}
/**
* 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;
}
static inline unsigned int crypto_skcipher_alg_chunksize(
struct skcipher_alg *alg)
{
if ((alg->base.cra_flags & CRYPTO_ALG_TYPE_MASK) ==
CRYPTO_ALG_TYPE_BLKCIPHER)
return alg->base.cra_blocksize;
if (alg->base.cra_ablkcipher.encrypt)
return alg->base.cra_blocksize;
return alg->chunksize;
}
static inline unsigned int crypto_skcipher_alg_walksize(
struct skcipher_alg *alg)
{
if ((alg->base.cra_flags & CRYPTO_ALG_TYPE_MASK) ==
CRYPTO_ALG_TYPE_BLKCIPHER)
return alg->base.cra_blocksize;
if (alg->base.cra_ablkcipher.encrypt)
return alg->base.cra_blocksize;
return alg->walksize;
}
/**
* crypto_skcipher_chunksize() - obtain chunk size
* @tfm: cipher handle
*
* The block size is set to one for ciphers such as CTR. However,
* you still need to provide incremental updates in multiples of
* the underlying block size as the IV does not have sub-block
* granularity. This is known in this API as the chunk size.
*
* Return: chunk size in bytes
*/
static inline unsigned int crypto_skcipher_chunksize(
struct crypto_skcipher *tfm)
{
return crypto_skcipher_alg_chunksize(crypto_skcipher_alg(tfm));
}
/**
* crypto_skcipher_walksize() - obtain walk size
* @tfm: cipher handle
*
* In some cases, algorithms can only perform optimally when operating on
* multiple blocks in parallel. This is reflected by the walksize, which
* must be a multiple of the chunksize (or equal if the concern does not
* apply)
*
* Return: walk size in bytes
*/
static inline unsigned int crypto_skcipher_walksize(
struct crypto_skcipher *tfm)
{
return crypto_skcipher_alg_walksize(crypto_skcipher_alg(tfm));
}
/**
* 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);
}
static inline bool crypto_skcipher_has_setkey(struct crypto_skcipher *tfm)
{
return tfm->keysize;
}
static inline unsigned int crypto_skcipher_default_keysize(
struct crypto_skcipher *tfm)
{
return tfm->keysize;
}
/**
* 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, 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;
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);
}
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 */