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