/*
* 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 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);
if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
return -ENOKEY;
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);
if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
return -ENOKEY;
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 */
