1 /* SPDX-License-Identifier: GPL-2.0-or-later */
3 * Symmetric key ciphers.
5 * Copyright (c) 2007-2015 Herbert Xu <herbert@gondor.apana.org.au>
8 #ifndef _CRYPTO_SKCIPHER_H
9 #define _CRYPTO_SKCIPHER_H
11 #include <linux/crypto.h>
12 #include <linux/kernel.h>
13 #include <linux/slab.h>
16 * struct skcipher_request - Symmetric key cipher request
17 * @cryptlen: Number of bytes to encrypt or decrypt
18 * @iv: Initialisation Vector
19 * @src: Source SG list
20 * @dst: Destination SG list
21 * @base: Underlying async request request
22 * @__ctx: Start of private context data
24 struct skcipher_request {
25 unsigned int cryptlen;
29 struct scatterlist *src;
30 struct scatterlist *dst;
32 struct crypto_async_request base;
34 void *__ctx[] CRYPTO_MINALIGN_ATTR;
37 struct crypto_skcipher {
38 int (*setkey)(struct crypto_skcipher *tfm, const u8 *key,
40 int (*encrypt)(struct skcipher_request *req);
41 int (*decrypt)(struct skcipher_request *req);
47 struct crypto_tfm base;
50 struct crypto_sync_skcipher {
51 struct crypto_skcipher base;
55 * struct skcipher_alg - symmetric key cipher definition
56 * @min_keysize: Minimum key size supported by the transformation. This is the
57 * smallest key length supported by this transformation algorithm.
58 * This must be set to one of the pre-defined values as this is
59 * not hardware specific. Possible values for this field can be
60 * found via git grep "_MIN_KEY_SIZE" include/crypto/
61 * @max_keysize: Maximum key size supported by the transformation. This is the
62 * largest key length supported by this transformation algorithm.
63 * This must be set to one of the pre-defined values as this is
64 * not hardware specific. Possible values for this field can be
65 * found via git grep "_MAX_KEY_SIZE" include/crypto/
66 * @setkey: Set key for the transformation. This function is used to either
67 * program a supplied key into the hardware or store the key in the
68 * transformation context for programming it later. Note that this
69 * function does modify the transformation context. This function can
70 * be called multiple times during the existence of the transformation
71 * object, so one must make sure the key is properly reprogrammed into
72 * the hardware. This function is also responsible for checking the key
73 * length for validity. In case a software fallback was put in place in
74 * the @cra_init call, this function might need to use the fallback if
75 * the algorithm doesn't support all of the key sizes.
76 * @encrypt: Encrypt a scatterlist of blocks. This function is used to encrypt
77 * the supplied scatterlist containing the blocks of data. The crypto
78 * API consumer is responsible for aligning the entries of the
79 * scatterlist properly and making sure the chunks are correctly
80 * sized. In case a software fallback was put in place in the
81 * @cra_init call, this function might need to use the fallback if
82 * the algorithm doesn't support all of the key sizes. In case the
83 * key was stored in transformation context, the key might need to be
84 * re-programmed into the hardware in this function. This function
85 * shall not modify the transformation context, as this function may
86 * be called in parallel with the same transformation object.
87 * @decrypt: Decrypt a single block. This is a reverse counterpart to @encrypt
88 * and the conditions are exactly the same.
89 * @init: Initialize the cryptographic transformation object. This function
90 * is used to initialize the cryptographic transformation object.
91 * This function is called only once at the instantiation time, right
92 * after the transformation context was allocated. In case the
93 * cryptographic hardware has some special requirements which need to
94 * be handled by software, this function shall check for the precise
95 * requirement of the transformation and put any software fallbacks
97 * @exit: Deinitialize the cryptographic transformation object. This is a
98 * counterpart to @init, used to remove various changes set in
100 * @ivsize: IV size applicable for transformation. The consumer must provide an
101 * IV of exactly that size to perform the encrypt or decrypt operation.
102 * @chunksize: Equal to the block size except for stream ciphers such as
103 * CTR where it is set to the underlying block size.
104 * @walksize: Equal to the chunk size except in cases where the algorithm is
105 * considerably more efficient if it can operate on multiple chunks
106 * in parallel. Should be a multiple of chunksize.
107 * @base: Definition of a generic crypto algorithm.
109 * All fields except @ivsize are mandatory and must be filled.
111 struct skcipher_alg {
112 int (*setkey)(struct crypto_skcipher *tfm, const u8 *key,
113 unsigned int keylen);
114 int (*encrypt)(struct skcipher_request *req);
115 int (*decrypt)(struct skcipher_request *req);
116 int (*init)(struct crypto_skcipher *tfm);
117 void (*exit)(struct crypto_skcipher *tfm);
119 unsigned int min_keysize;
120 unsigned int max_keysize;
122 unsigned int chunksize;
123 unsigned int walksize;
125 struct crypto_alg base;
128 #define MAX_SYNC_SKCIPHER_REQSIZE 384
130 * This performs a type-check against the "tfm" argument to make sure
131 * all users have the correct skcipher tfm for doing on-stack requests.
133 #define SYNC_SKCIPHER_REQUEST_ON_STACK(name, tfm) \
134 char __##name##_desc[sizeof(struct skcipher_request) + \
135 MAX_SYNC_SKCIPHER_REQSIZE + \
136 (!(sizeof((struct crypto_sync_skcipher *)1 == \
138 ] CRYPTO_MINALIGN_ATTR; \
139 struct skcipher_request *name = (void *)__##name##_desc
142 * DOC: Symmetric Key Cipher API
144 * Symmetric key cipher API is used with the ciphers of type
145 * CRYPTO_ALG_TYPE_SKCIPHER (listed as type "skcipher" in /proc/crypto).
147 * Asynchronous cipher operations imply that the function invocation for a
148 * cipher request returns immediately before the completion of the operation.
149 * The cipher request is scheduled as a separate kernel thread and therefore
150 * load-balanced on the different CPUs via the process scheduler. To allow
151 * the kernel crypto API to inform the caller about the completion of a cipher
152 * request, the caller must provide a callback function. That function is
153 * invoked with the cipher handle when the request completes.
155 * To support the asynchronous operation, additional information than just the
156 * cipher handle must be supplied to the kernel crypto API. That additional
157 * information is given by filling in the skcipher_request data structure.
159 * For the symmetric key cipher API, the state is maintained with the tfm
160 * cipher handle. A single tfm can be used across multiple calls and in
161 * parallel. For asynchronous block cipher calls, context data supplied and
162 * only used by the caller can be referenced the request data structure in
163 * addition to the IV used for the cipher request. The maintenance of such
164 * state information would be important for a crypto driver implementer to
165 * have, because when calling the callback function upon completion of the
166 * cipher operation, that callback function may need some information about
167 * which operation just finished if it invoked multiple in parallel. This
168 * state information is unused by the kernel crypto API.
171 static inline struct crypto_skcipher *__crypto_skcipher_cast(
172 struct crypto_tfm *tfm)
174 return container_of(tfm, struct crypto_skcipher, base);
178 * crypto_alloc_skcipher() - allocate symmetric key cipher handle
179 * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
181 * @type: specifies the type of the cipher
182 * @mask: specifies the mask for the cipher
184 * Allocate a cipher handle for an skcipher. The returned struct
185 * crypto_skcipher is the cipher handle that is required for any subsequent
186 * API invocation for that skcipher.
188 * Return: allocated cipher handle in case of success; IS_ERR() is true in case
189 * of an error, PTR_ERR() returns the error code.
191 struct crypto_skcipher *crypto_alloc_skcipher(const char *alg_name,
194 struct crypto_sync_skcipher *crypto_alloc_sync_skcipher(const char *alg_name,
197 static inline struct crypto_tfm *crypto_skcipher_tfm(
198 struct crypto_skcipher *tfm)
204 * crypto_free_skcipher() - zeroize and free cipher handle
205 * @tfm: cipher handle to be freed
207 static inline void crypto_free_skcipher(struct crypto_skcipher *tfm)
209 crypto_destroy_tfm(tfm, crypto_skcipher_tfm(tfm));
212 static inline void crypto_free_sync_skcipher(struct crypto_sync_skcipher *tfm)
214 crypto_free_skcipher(&tfm->base);
218 * crypto_has_skcipher() - Search for the availability of an skcipher.
219 * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
221 * @type: specifies the type of the skcipher
222 * @mask: specifies the mask for the skcipher
224 * Return: true when the skcipher is known to the kernel crypto API; false
227 int crypto_has_skcipher(const char *alg_name, u32 type, u32 mask);
229 static inline const char *crypto_skcipher_driver_name(
230 struct crypto_skcipher *tfm)
232 return crypto_tfm_alg_driver_name(crypto_skcipher_tfm(tfm));
235 static inline struct skcipher_alg *crypto_skcipher_alg(
236 struct crypto_skcipher *tfm)
238 return container_of(crypto_skcipher_tfm(tfm)->__crt_alg,
239 struct skcipher_alg, base);
242 static inline unsigned int crypto_skcipher_alg_ivsize(struct skcipher_alg *alg)
248 * crypto_skcipher_ivsize() - obtain IV size
249 * @tfm: cipher handle
251 * The size of the IV for the skcipher referenced by the cipher handle is
252 * returned. This IV size may be zero if the cipher does not need an IV.
254 * Return: IV size in bytes
256 static inline unsigned int crypto_skcipher_ivsize(struct crypto_skcipher *tfm)
261 static inline unsigned int crypto_sync_skcipher_ivsize(
262 struct crypto_sync_skcipher *tfm)
264 return crypto_skcipher_ivsize(&tfm->base);
268 * crypto_skcipher_blocksize() - obtain block size of cipher
269 * @tfm: cipher handle
271 * The block size for the skcipher referenced with the cipher handle is
272 * returned. The caller may use that information to allocate appropriate
273 * memory for the data returned by the encryption or decryption operation
275 * Return: block size of cipher
277 static inline unsigned int crypto_skcipher_blocksize(
278 struct crypto_skcipher *tfm)
280 return crypto_tfm_alg_blocksize(crypto_skcipher_tfm(tfm));
283 static inline unsigned int crypto_skcipher_alg_chunksize(
284 struct skcipher_alg *alg)
286 return alg->chunksize;
290 * crypto_skcipher_chunksize() - obtain chunk size
291 * @tfm: cipher handle
293 * The block size is set to one for ciphers such as CTR. However,
294 * you still need to provide incremental updates in multiples of
295 * the underlying block size as the IV does not have sub-block
296 * granularity. This is known in this API as the chunk size.
298 * Return: chunk size in bytes
300 static inline unsigned int crypto_skcipher_chunksize(
301 struct crypto_skcipher *tfm)
303 return crypto_skcipher_alg_chunksize(crypto_skcipher_alg(tfm));
306 static inline unsigned int crypto_sync_skcipher_blocksize(
307 struct crypto_sync_skcipher *tfm)
309 return crypto_skcipher_blocksize(&tfm->base);
312 static inline unsigned int crypto_skcipher_alignmask(
313 struct crypto_skcipher *tfm)
315 return crypto_tfm_alg_alignmask(crypto_skcipher_tfm(tfm));
318 static inline u32 crypto_skcipher_get_flags(struct crypto_skcipher *tfm)
320 return crypto_tfm_get_flags(crypto_skcipher_tfm(tfm));
323 static inline void crypto_skcipher_set_flags(struct crypto_skcipher *tfm,
326 crypto_tfm_set_flags(crypto_skcipher_tfm(tfm), flags);
329 static inline void crypto_skcipher_clear_flags(struct crypto_skcipher *tfm,
332 crypto_tfm_clear_flags(crypto_skcipher_tfm(tfm), flags);
335 static inline u32 crypto_sync_skcipher_get_flags(
336 struct crypto_sync_skcipher *tfm)
338 return crypto_skcipher_get_flags(&tfm->base);
341 static inline void crypto_sync_skcipher_set_flags(
342 struct crypto_sync_skcipher *tfm, u32 flags)
344 crypto_skcipher_set_flags(&tfm->base, flags);
347 static inline void crypto_sync_skcipher_clear_flags(
348 struct crypto_sync_skcipher *tfm, u32 flags)
350 crypto_skcipher_clear_flags(&tfm->base, flags);
354 * crypto_skcipher_setkey() - set key for cipher
355 * @tfm: cipher handle
356 * @key: buffer holding the key
357 * @keylen: length of the key in bytes
359 * The caller provided key is set for the skcipher referenced by the cipher
362 * Note, the key length determines the cipher type. Many block ciphers implement
363 * different cipher modes depending on the key size, such as AES-128 vs AES-192
364 * vs. AES-256. When providing a 16 byte key for an AES cipher handle, AES-128
367 * Return: 0 if the setting of the key was successful; < 0 if an error occurred
369 static inline int crypto_skcipher_setkey(struct crypto_skcipher *tfm,
370 const u8 *key, unsigned int keylen)
372 return tfm->setkey(tfm, key, keylen);
375 static inline int crypto_sync_skcipher_setkey(struct crypto_sync_skcipher *tfm,
376 const u8 *key, unsigned int keylen)
378 return crypto_skcipher_setkey(&tfm->base, key, keylen);
381 static inline unsigned int crypto_skcipher_default_keysize(
382 struct crypto_skcipher *tfm)
388 * crypto_skcipher_reqtfm() - obtain cipher handle from request
389 * @req: skcipher_request out of which the cipher handle is to be obtained
391 * Return the crypto_skcipher handle when furnishing an skcipher_request
394 * Return: crypto_skcipher handle
396 static inline struct crypto_skcipher *crypto_skcipher_reqtfm(
397 struct skcipher_request *req)
399 return __crypto_skcipher_cast(req->base.tfm);
402 static inline struct crypto_sync_skcipher *crypto_sync_skcipher_reqtfm(
403 struct skcipher_request *req)
405 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
407 return container_of(tfm, struct crypto_sync_skcipher, base);
411 * crypto_skcipher_encrypt() - encrypt plaintext
412 * @req: reference to the skcipher_request handle that holds all information
413 * needed to perform the cipher operation
415 * Encrypt plaintext data using the skcipher_request handle. That data
416 * structure and how it is filled with data is discussed with the
417 * skcipher_request_* functions.
419 * Return: 0 if the cipher operation was successful; < 0 if an error occurred
421 int crypto_skcipher_encrypt(struct skcipher_request *req);
424 * crypto_skcipher_decrypt() - decrypt ciphertext
425 * @req: reference to the skcipher_request handle that holds all information
426 * needed to perform the cipher operation
428 * Decrypt ciphertext data using the skcipher_request handle. That data
429 * structure and how it is filled with data is discussed with the
430 * skcipher_request_* functions.
432 * Return: 0 if the cipher operation was successful; < 0 if an error occurred
434 int crypto_skcipher_decrypt(struct skcipher_request *req);
437 * DOC: Symmetric Key Cipher Request Handle
439 * The skcipher_request data structure contains all pointers to data
440 * required for the symmetric key cipher operation. This includes the cipher
441 * handle (which can be used by multiple skcipher_request instances), pointer
442 * to plaintext and ciphertext, asynchronous callback function, etc. It acts
443 * as a handle to the skcipher_request_* API calls in a similar way as
444 * skcipher handle to the crypto_skcipher_* API calls.
448 * crypto_skcipher_reqsize() - obtain size of the request data structure
449 * @tfm: cipher handle
451 * Return: number of bytes
453 static inline unsigned int crypto_skcipher_reqsize(struct crypto_skcipher *tfm)
459 * skcipher_request_set_tfm() - update cipher handle reference in request
460 * @req: request handle to be modified
461 * @tfm: cipher handle that shall be added to the request handle
463 * Allow the caller to replace the existing skcipher handle in the request
464 * data structure with a different one.
466 static inline void skcipher_request_set_tfm(struct skcipher_request *req,
467 struct crypto_skcipher *tfm)
469 req->base.tfm = crypto_skcipher_tfm(tfm);
472 static inline void skcipher_request_set_sync_tfm(struct skcipher_request *req,
473 struct crypto_sync_skcipher *tfm)
475 skcipher_request_set_tfm(req, &tfm->base);
478 static inline struct skcipher_request *skcipher_request_cast(
479 struct crypto_async_request *req)
481 return container_of(req, struct skcipher_request, base);
485 * skcipher_request_alloc() - allocate request data structure
486 * @tfm: cipher handle to be registered with the request
487 * @gfp: memory allocation flag that is handed to kmalloc by the API call.
489 * Allocate the request data structure that must be used with the skcipher
490 * encrypt and decrypt API calls. During the allocation, the provided skcipher
491 * handle is registered in the request data structure.
493 * Return: allocated request handle in case of success, or NULL if out of memory
495 static inline struct skcipher_request *skcipher_request_alloc(
496 struct crypto_skcipher *tfm, gfp_t gfp)
498 struct skcipher_request *req;
500 req = kmalloc(sizeof(struct skcipher_request) +
501 crypto_skcipher_reqsize(tfm), gfp);
504 skcipher_request_set_tfm(req, tfm);
510 * skcipher_request_free() - zeroize and free request data structure
511 * @req: request data structure cipher handle to be freed
513 static inline void skcipher_request_free(struct skcipher_request *req)
518 static inline void skcipher_request_zero(struct skcipher_request *req)
520 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
522 memzero_explicit(req, sizeof(*req) + crypto_skcipher_reqsize(tfm));
526 * skcipher_request_set_callback() - set asynchronous callback function
527 * @req: request handle
528 * @flags: specify zero or an ORing of the flags
529 * CRYPTO_TFM_REQ_MAY_BACKLOG the request queue may back log and
530 * increase the wait queue beyond the initial maximum size;
531 * CRYPTO_TFM_REQ_MAY_SLEEP the request processing may sleep
532 * @compl: callback function pointer to be registered with the request handle
533 * @data: The data pointer refers to memory that is not used by the kernel
534 * crypto API, but provided to the callback function for it to use. Here,
535 * the caller can provide a reference to memory the callback function can
536 * operate on. As the callback function is invoked asynchronously to the
537 * related functionality, it may need to access data structures of the
538 * related functionality which can be referenced using this pointer. The
539 * callback function can access the memory via the "data" field in the
540 * crypto_async_request data structure provided to the callback function.
542 * This function allows setting the callback function that is triggered once the
543 * cipher operation completes.
545 * The callback function is registered with the skcipher_request handle and
546 * must comply with the following template::
548 * void callback_function(struct crypto_async_request *req, int error)
550 static inline void skcipher_request_set_callback(struct skcipher_request *req,
552 crypto_completion_t compl,
555 req->base.complete = compl;
556 req->base.data = data;
557 req->base.flags = flags;
561 * skcipher_request_set_crypt() - set data buffers
562 * @req: request handle
563 * @src: source scatter / gather list
564 * @dst: destination scatter / gather list
565 * @cryptlen: number of bytes to process from @src
566 * @iv: IV for the cipher operation which must comply with the IV size defined
567 * by crypto_skcipher_ivsize
569 * This function allows setting of the source data and destination data
570 * scatter / gather lists.
572 * For encryption, the source is treated as the plaintext and the
573 * destination is the ciphertext. For a decryption operation, the use is
574 * reversed - the source is the ciphertext and the destination is the plaintext.
576 static inline void skcipher_request_set_crypt(
577 struct skcipher_request *req,
578 struct scatterlist *src, struct scatterlist *dst,
579 unsigned int cryptlen, void *iv)
583 req->cryptlen = cryptlen;
587 #endif /* _CRYPTO_SKCIPHER_H */