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 cipher
222 * @mask: specifies the mask for the cipher
224 * Return: true when the skcipher is known to the kernel crypto API; false
227 static inline int crypto_has_skcipher(const char *alg_name
, u32 type
,
230 return crypto_has_alg(alg_name
, crypto_skcipher_type(type
),
231 crypto_skcipher_mask(mask
));
235 * crypto_has_skcipher2() - Search for the availability of an skcipher.
236 * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
238 * @type: specifies the type of the skcipher
239 * @mask: specifies the mask for the skcipher
241 * Return: true when the skcipher is known to the kernel crypto API; false
244 int crypto_has_skcipher2(const char *alg_name
, u32 type
, u32 mask
);
246 static inline const char *crypto_skcipher_driver_name(
247 struct crypto_skcipher
*tfm
)
249 return crypto_tfm_alg_driver_name(crypto_skcipher_tfm(tfm
));
252 static inline struct skcipher_alg
*crypto_skcipher_alg(
253 struct crypto_skcipher
*tfm
)
255 return container_of(crypto_skcipher_tfm(tfm
)->__crt_alg
,
256 struct skcipher_alg
, base
);
259 static inline unsigned int crypto_skcipher_alg_ivsize(struct skcipher_alg
*alg
)
261 if ((alg
->base
.cra_flags
& CRYPTO_ALG_TYPE_MASK
) ==
262 CRYPTO_ALG_TYPE_BLKCIPHER
)
263 return alg
->base
.cra_blkcipher
.ivsize
;
265 if (alg
->base
.cra_ablkcipher
.encrypt
)
266 return alg
->base
.cra_ablkcipher
.ivsize
;
272 * crypto_skcipher_ivsize() - obtain IV size
273 * @tfm: cipher handle
275 * The size of the IV for the skcipher referenced by the cipher handle is
276 * returned. This IV size may be zero if the cipher does not need an IV.
278 * Return: IV size in bytes
280 static inline unsigned int crypto_skcipher_ivsize(struct crypto_skcipher
*tfm
)
285 static inline unsigned int crypto_sync_skcipher_ivsize(
286 struct crypto_sync_skcipher
*tfm
)
288 return crypto_skcipher_ivsize(&tfm
->base
);
291 static inline unsigned int crypto_skcipher_alg_chunksize(
292 struct skcipher_alg
*alg
)
294 if ((alg
->base
.cra_flags
& CRYPTO_ALG_TYPE_MASK
) ==
295 CRYPTO_ALG_TYPE_BLKCIPHER
)
296 return alg
->base
.cra_blocksize
;
298 if (alg
->base
.cra_ablkcipher
.encrypt
)
299 return alg
->base
.cra_blocksize
;
301 return alg
->chunksize
;
304 static inline unsigned int crypto_skcipher_alg_walksize(
305 struct skcipher_alg
*alg
)
307 if ((alg
->base
.cra_flags
& CRYPTO_ALG_TYPE_MASK
) ==
308 CRYPTO_ALG_TYPE_BLKCIPHER
)
309 return alg
->base
.cra_blocksize
;
311 if (alg
->base
.cra_ablkcipher
.encrypt
)
312 return alg
->base
.cra_blocksize
;
314 return alg
->walksize
;
318 * crypto_skcipher_chunksize() - obtain chunk size
319 * @tfm: cipher handle
321 * The block size is set to one for ciphers such as CTR. However,
322 * you still need to provide incremental updates in multiples of
323 * the underlying block size as the IV does not have sub-block
324 * granularity. This is known in this API as the chunk size.
326 * Return: chunk size in bytes
328 static inline unsigned int crypto_skcipher_chunksize(
329 struct crypto_skcipher
*tfm
)
331 return crypto_skcipher_alg_chunksize(crypto_skcipher_alg(tfm
));
335 * crypto_skcipher_walksize() - obtain walk size
336 * @tfm: cipher handle
338 * In some cases, algorithms can only perform optimally when operating on
339 * multiple blocks in parallel. This is reflected by the walksize, which
340 * must be a multiple of the chunksize (or equal if the concern does not
343 * Return: walk size in bytes
345 static inline unsigned int crypto_skcipher_walksize(
346 struct crypto_skcipher
*tfm
)
348 return crypto_skcipher_alg_walksize(crypto_skcipher_alg(tfm
));
352 * crypto_skcipher_blocksize() - obtain block size of cipher
353 * @tfm: cipher handle
355 * The block size for the skcipher referenced with the cipher handle is
356 * returned. The caller may use that information to allocate appropriate
357 * memory for the data returned by the encryption or decryption operation
359 * Return: block size of cipher
361 static inline unsigned int crypto_skcipher_blocksize(
362 struct crypto_skcipher
*tfm
)
364 return crypto_tfm_alg_blocksize(crypto_skcipher_tfm(tfm
));
367 static inline unsigned int crypto_sync_skcipher_blocksize(
368 struct crypto_sync_skcipher
*tfm
)
370 return crypto_skcipher_blocksize(&tfm
->base
);
373 static inline unsigned int crypto_skcipher_alignmask(
374 struct crypto_skcipher
*tfm
)
376 return crypto_tfm_alg_alignmask(crypto_skcipher_tfm(tfm
));
379 static inline u32
crypto_skcipher_get_flags(struct crypto_skcipher
*tfm
)
381 return crypto_tfm_get_flags(crypto_skcipher_tfm(tfm
));
384 static inline void crypto_skcipher_set_flags(struct crypto_skcipher
*tfm
,
387 crypto_tfm_set_flags(crypto_skcipher_tfm(tfm
), flags
);
390 static inline void crypto_skcipher_clear_flags(struct crypto_skcipher
*tfm
,
393 crypto_tfm_clear_flags(crypto_skcipher_tfm(tfm
), flags
);
396 static inline u32
crypto_sync_skcipher_get_flags(
397 struct crypto_sync_skcipher
*tfm
)
399 return crypto_skcipher_get_flags(&tfm
->base
);
402 static inline void crypto_sync_skcipher_set_flags(
403 struct crypto_sync_skcipher
*tfm
, u32 flags
)
405 crypto_skcipher_set_flags(&tfm
->base
, flags
);
408 static inline void crypto_sync_skcipher_clear_flags(
409 struct crypto_sync_skcipher
*tfm
, u32 flags
)
411 crypto_skcipher_clear_flags(&tfm
->base
, flags
);
415 * crypto_skcipher_setkey() - set key for cipher
416 * @tfm: cipher handle
417 * @key: buffer holding the key
418 * @keylen: length of the key in bytes
420 * The caller provided key is set for the skcipher referenced by the cipher
423 * Note, the key length determines the cipher type. Many block ciphers implement
424 * different cipher modes depending on the key size, such as AES-128 vs AES-192
425 * vs. AES-256. When providing a 16 byte key for an AES cipher handle, AES-128
428 * Return: 0 if the setting of the key was successful; < 0 if an error occurred
430 static inline int crypto_skcipher_setkey(struct crypto_skcipher
*tfm
,
431 const u8
*key
, unsigned int keylen
)
433 return tfm
->setkey(tfm
, key
, keylen
);
436 static inline int crypto_sync_skcipher_setkey(struct crypto_sync_skcipher
*tfm
,
437 const u8
*key
, unsigned int keylen
)
439 return crypto_skcipher_setkey(&tfm
->base
, key
, keylen
);
442 static inline unsigned int crypto_skcipher_default_keysize(
443 struct crypto_skcipher
*tfm
)
449 * crypto_skcipher_reqtfm() - obtain cipher handle from request
450 * @req: skcipher_request out of which the cipher handle is to be obtained
452 * Return the crypto_skcipher handle when furnishing an skcipher_request
455 * Return: crypto_skcipher handle
457 static inline struct crypto_skcipher
*crypto_skcipher_reqtfm(
458 struct skcipher_request
*req
)
460 return __crypto_skcipher_cast(req
->base
.tfm
);
463 static inline struct crypto_sync_skcipher
*crypto_sync_skcipher_reqtfm(
464 struct skcipher_request
*req
)
466 struct crypto_skcipher
*tfm
= crypto_skcipher_reqtfm(req
);
468 return container_of(tfm
, struct crypto_sync_skcipher
, base
);
472 * crypto_skcipher_encrypt() - encrypt plaintext
473 * @req: reference to the skcipher_request handle that holds all information
474 * needed to perform the cipher operation
476 * Encrypt plaintext data using the skcipher_request handle. That data
477 * structure and how it is filled with data is discussed with the
478 * skcipher_request_* functions.
480 * Return: 0 if the cipher operation was successful; < 0 if an error occurred
482 static inline int crypto_skcipher_encrypt(struct skcipher_request
*req
)
484 struct crypto_skcipher
*tfm
= crypto_skcipher_reqtfm(req
);
485 struct crypto_alg
*alg
= tfm
->base
.__crt_alg
;
486 unsigned int cryptlen
= req
->cryptlen
;
489 crypto_stats_get(alg
);
490 if (crypto_skcipher_get_flags(tfm
) & CRYPTO_TFM_NEED_KEY
)
493 ret
= tfm
->encrypt(req
);
494 crypto_stats_skcipher_encrypt(cryptlen
, ret
, alg
);
499 * crypto_skcipher_decrypt() - decrypt ciphertext
500 * @req: reference to the skcipher_request handle that holds all information
501 * needed to perform the cipher operation
503 * Decrypt ciphertext data using the skcipher_request handle. That data
504 * structure and how it is filled with data is discussed with the
505 * skcipher_request_* functions.
507 * Return: 0 if the cipher operation was successful; < 0 if an error occurred
509 static inline int crypto_skcipher_decrypt(struct skcipher_request
*req
)
511 struct crypto_skcipher
*tfm
= crypto_skcipher_reqtfm(req
);
512 struct crypto_alg
*alg
= tfm
->base
.__crt_alg
;
513 unsigned int cryptlen
= req
->cryptlen
;
516 crypto_stats_get(alg
);
517 if (crypto_skcipher_get_flags(tfm
) & CRYPTO_TFM_NEED_KEY
)
520 ret
= tfm
->decrypt(req
);
521 crypto_stats_skcipher_decrypt(cryptlen
, ret
, alg
);
526 * DOC: Symmetric Key Cipher Request Handle
528 * The skcipher_request data structure contains all pointers to data
529 * required for the symmetric key cipher operation. This includes the cipher
530 * handle (which can be used by multiple skcipher_request instances), pointer
531 * to plaintext and ciphertext, asynchronous callback function, etc. It acts
532 * as a handle to the skcipher_request_* API calls in a similar way as
533 * skcipher handle to the crypto_skcipher_* API calls.
537 * crypto_skcipher_reqsize() - obtain size of the request data structure
538 * @tfm: cipher handle
540 * Return: number of bytes
542 static inline unsigned int crypto_skcipher_reqsize(struct crypto_skcipher
*tfm
)
548 * skcipher_request_set_tfm() - update cipher handle reference in request
549 * @req: request handle to be modified
550 * @tfm: cipher handle that shall be added to the request handle
552 * Allow the caller to replace the existing skcipher handle in the request
553 * data structure with a different one.
555 static inline void skcipher_request_set_tfm(struct skcipher_request
*req
,
556 struct crypto_skcipher
*tfm
)
558 req
->base
.tfm
= crypto_skcipher_tfm(tfm
);
561 static inline void skcipher_request_set_sync_tfm(struct skcipher_request
*req
,
562 struct crypto_sync_skcipher
*tfm
)
564 skcipher_request_set_tfm(req
, &tfm
->base
);
567 static inline struct skcipher_request
*skcipher_request_cast(
568 struct crypto_async_request
*req
)
570 return container_of(req
, struct skcipher_request
, base
);
574 * skcipher_request_alloc() - allocate request data structure
575 * @tfm: cipher handle to be registered with the request
576 * @gfp: memory allocation flag that is handed to kmalloc by the API call.
578 * Allocate the request data structure that must be used with the skcipher
579 * encrypt and decrypt API calls. During the allocation, the provided skcipher
580 * handle is registered in the request data structure.
582 * Return: allocated request handle in case of success, or NULL if out of memory
584 static inline struct skcipher_request
*skcipher_request_alloc(
585 struct crypto_skcipher
*tfm
, gfp_t gfp
)
587 struct skcipher_request
*req
;
589 req
= kmalloc(sizeof(struct skcipher_request
) +
590 crypto_skcipher_reqsize(tfm
), gfp
);
593 skcipher_request_set_tfm(req
, tfm
);
599 * skcipher_request_free() - zeroize and free request data structure
600 * @req: request data structure cipher handle to be freed
602 static inline void skcipher_request_free(struct skcipher_request
*req
)
607 static inline void skcipher_request_zero(struct skcipher_request
*req
)
609 struct crypto_skcipher
*tfm
= crypto_skcipher_reqtfm(req
);
611 memzero_explicit(req
, sizeof(*req
) + crypto_skcipher_reqsize(tfm
));
615 * skcipher_request_set_callback() - set asynchronous callback function
616 * @req: request handle
617 * @flags: specify zero or an ORing of the flags
618 * CRYPTO_TFM_REQ_MAY_BACKLOG the request queue may back log and
619 * increase the wait queue beyond the initial maximum size;
620 * CRYPTO_TFM_REQ_MAY_SLEEP the request processing may sleep
621 * @compl: callback function pointer to be registered with the request handle
622 * @data: The data pointer refers to memory that is not used by the kernel
623 * crypto API, but provided to the callback function for it to use. Here,
624 * the caller can provide a reference to memory the callback function can
625 * operate on. As the callback function is invoked asynchronously to the
626 * related functionality, it may need to access data structures of the
627 * related functionality which can be referenced using this pointer. The
628 * callback function can access the memory via the "data" field in the
629 * crypto_async_request data structure provided to the callback function.
631 * This function allows setting the callback function that is triggered once the
632 * cipher operation completes.
634 * The callback function is registered with the skcipher_request handle and
635 * must comply with the following template::
637 * void callback_function(struct crypto_async_request *req, int error)
639 static inline void skcipher_request_set_callback(struct skcipher_request
*req
,
641 crypto_completion_t
compl,
644 req
->base
.complete
= compl;
645 req
->base
.data
= data
;
646 req
->base
.flags
= flags
;
650 * skcipher_request_set_crypt() - set data buffers
651 * @req: request handle
652 * @src: source scatter / gather list
653 * @dst: destination scatter / gather list
654 * @cryptlen: number of bytes to process from @src
655 * @iv: IV for the cipher operation which must comply with the IV size defined
656 * by crypto_skcipher_ivsize
658 * This function allows setting of the source data and destination data
659 * scatter / gather lists.
661 * For encryption, the source is treated as the plaintext and the
662 * destination is the ciphertext. For a decryption operation, the use is
663 * reversed - the source is the ciphertext and the destination is the plaintext.
665 static inline void skcipher_request_set_crypt(
666 struct skcipher_request
*req
,
667 struct scatterlist
*src
, struct scatterlist
*dst
,
668 unsigned int cryptlen
, void *iv
)
672 req
->cryptlen
= cryptlen
;
676 #endif /* _CRYPTO_SKCIPHER_H */