diff options
Diffstat (limited to 'include/crypto/skcipher.h')
| -rw-r--r-- | include/crypto/skcipher.h | 391 |
1 files changed, 390 insertions, 1 deletions
diff --git a/include/crypto/skcipher.h b/include/crypto/skcipher.h index 07d245f07..d8dd41fb0 100644 --- a/include/crypto/skcipher.h +++ b/include/crypto/skcipher.h @@ -1,7 +1,7 @@ /* * 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 @@ -18,6 +18,28 @@ #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 @@ -30,6 +52,23 @@ struct skcipher_givcrypt_request { 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; + + 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) { @@ -106,5 +145,355 @@ static inline void skcipher_givcrypt_set_giv( 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); +} + +/** + * 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 */ |