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| -rw-r--r-- | include/crypto/skcipher.h | 615 |
1 files changed, 615 insertions, 0 deletions
diff --git a/include/crypto/skcipher.h b/include/crypto/skcipher.h new file mode 100644 index 000000000..c7553f8b1 --- /dev/null +++ b/include/crypto/skcipher.h @@ -0,0 +1,615 @@ +/* + * 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 + * + * If @tfm is a NULL or error pointer, this function does nothing. + */ +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 */ + |