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/atomic.h>
12 #include <linux/container_of.h>
13 #include <linux/crypto.h>
14 #include <linux/slab.h>
15 #include <linux/string.h>
16 #include <linux/types.h>
21 * struct skcipher_request - Symmetric key cipher request
22 * @cryptlen: Number of bytes to encrypt or decrypt
23 * @iv: Initialisation Vector
24 * @src: Source SG list
25 * @dst: Destination SG list
26 * @base: Underlying async request
27 * @__ctx: Start of private context data
29 struct skcipher_request {
30 unsigned int cryptlen;
34 struct scatterlist *src;
35 struct scatterlist *dst;
37 struct crypto_async_request base;
39 void *__ctx[] CRYPTO_MINALIGN_ATTR;
42 struct crypto_skcipher {
45 struct crypto_tfm base;
48 struct crypto_sync_skcipher {
49 struct crypto_skcipher base;
53 * struct crypto_istat_cipher - statistics for cipher algorithm
54 * @encrypt_cnt: number of encrypt requests
55 * @encrypt_tlen: total data size handled by encrypt requests
56 * @decrypt_cnt: number of decrypt requests
57 * @decrypt_tlen: total data size handled by decrypt requests
58 * @err_cnt: number of error for cipher requests
60 struct crypto_istat_cipher {
61 atomic64_t encrypt_cnt;
62 atomic64_t encrypt_tlen;
63 atomic64_t decrypt_cnt;
64 atomic64_t decrypt_tlen;
69 * struct skcipher_alg - symmetric key cipher definition
70 * @min_keysize: Minimum key size supported by the transformation. This is the
71 * smallest key length supported by this transformation algorithm.
72 * This must be set to one of the pre-defined values as this is
73 * not hardware specific. Possible values for this field can be
74 * found via git grep "_MIN_KEY_SIZE" include/crypto/
75 * @max_keysize: Maximum key size supported by the transformation. This is the
76 * largest key length supported by this transformation algorithm.
77 * This must be set to one of the pre-defined values as this is
78 * not hardware specific. Possible values for this field can be
79 * found via git grep "_MAX_KEY_SIZE" include/crypto/
80 * @setkey: Set key for the transformation. This function is used to either
81 * program a supplied key into the hardware or store the key in the
82 * transformation context for programming it later. Note that this
83 * function does modify the transformation context. This function can
84 * be called multiple times during the existence of the transformation
85 * object, so one must make sure the key is properly reprogrammed into
86 * the hardware. This function is also responsible for checking the key
87 * length for validity. In case a software fallback was put in place in
88 * the @cra_init call, this function might need to use the fallback if
89 * the algorithm doesn't support all of the key sizes.
90 * @encrypt: Encrypt a scatterlist of blocks. This function is used to encrypt
91 * the supplied scatterlist containing the blocks of data. The crypto
92 * API consumer is responsible for aligning the entries of the
93 * scatterlist properly and making sure the chunks are correctly
94 * sized. In case a software fallback was put in place in the
95 * @cra_init call, this function might need to use the fallback if
96 * the algorithm doesn't support all of the key sizes. In case the
97 * key was stored in transformation context, the key might need to be
98 * re-programmed into the hardware in this function. This function
99 * shall not modify the transformation context, as this function may
100 * be called in parallel with the same transformation object.
101 * @decrypt: Decrypt a single block. This is a reverse counterpart to @encrypt
102 * and the conditions are exactly the same.
103 * @init: Initialize the cryptographic transformation object. This function
104 * is used to initialize the cryptographic transformation object.
105 * This function is called only once at the instantiation time, right
106 * after the transformation context was allocated. In case the
107 * cryptographic hardware has some special requirements which need to
108 * be handled by software, this function shall check for the precise
109 * requirement of the transformation and put any software fallbacks
111 * @exit: Deinitialize the cryptographic transformation object. This is a
112 * counterpart to @init, used to remove various changes set in
114 * @ivsize: IV size applicable for transformation. The consumer must provide an
115 * IV of exactly that size to perform the encrypt or decrypt operation.
116 * @chunksize: Equal to the block size except for stream ciphers such as
117 * CTR where it is set to the underlying block size.
118 * @walksize: Equal to the chunk size except in cases where the algorithm is
119 * considerably more efficient if it can operate on multiple chunks
120 * in parallel. Should be a multiple of chunksize.
121 * @stat: Statistics for cipher algorithm
122 * @base: Definition of a generic crypto algorithm.
124 * All fields except @ivsize are mandatory and must be filled.
126 struct skcipher_alg {
127 int (*setkey)(struct crypto_skcipher *tfm, const u8 *key,
128 unsigned int keylen);
129 int (*encrypt)(struct skcipher_request *req);
130 int (*decrypt)(struct skcipher_request *req);
131 int (*init)(struct crypto_skcipher *tfm);
132 void (*exit)(struct crypto_skcipher *tfm);
134 unsigned int min_keysize;
135 unsigned int max_keysize;
137 unsigned int chunksize;
138 unsigned int walksize;
140 #ifdef CONFIG_CRYPTO_STATS
141 struct crypto_istat_cipher stat;
144 struct crypto_alg base;
147 #define MAX_SYNC_SKCIPHER_REQSIZE 384
149 * This performs a type-check against the "tfm" argument to make sure
150 * all users have the correct skcipher tfm for doing on-stack requests.
152 #define SYNC_SKCIPHER_REQUEST_ON_STACK(name, tfm) \
153 char __##name##_desc[sizeof(struct skcipher_request) + \
154 MAX_SYNC_SKCIPHER_REQSIZE + \
155 (!(sizeof((struct crypto_sync_skcipher *)1 == \
157 ] CRYPTO_MINALIGN_ATTR; \
158 struct skcipher_request *name = (void *)__##name##_desc
161 * DOC: Symmetric Key Cipher API
163 * Symmetric key cipher API is used with the ciphers of type
164 * CRYPTO_ALG_TYPE_SKCIPHER (listed as type "skcipher" in /proc/crypto).
166 * Asynchronous cipher operations imply that the function invocation for a
167 * cipher request returns immediately before the completion of the operation.
168 * The cipher request is scheduled as a separate kernel thread and therefore
169 * load-balanced on the different CPUs via the process scheduler. To allow
170 * the kernel crypto API to inform the caller about the completion of a cipher
171 * request, the caller must provide a callback function. That function is
172 * invoked with the cipher handle when the request completes.
174 * To support the asynchronous operation, additional information than just the
175 * cipher handle must be supplied to the kernel crypto API. That additional
176 * information is given by filling in the skcipher_request data structure.
178 * For the symmetric key cipher API, the state is maintained with the tfm
179 * cipher handle. A single tfm can be used across multiple calls and in
180 * parallel. For asynchronous block cipher calls, context data supplied and
181 * only used by the caller can be referenced the request data structure in
182 * addition to the IV used for the cipher request. The maintenance of such
183 * state information would be important for a crypto driver implementer to
184 * have, because when calling the callback function upon completion of the
185 * cipher operation, that callback function may need some information about
186 * which operation just finished if it invoked multiple in parallel. This
187 * state information is unused by the kernel crypto API.
190 static inline struct crypto_skcipher *__crypto_skcipher_cast(
191 struct crypto_tfm *tfm)
193 return container_of(tfm, struct crypto_skcipher, base);
197 * crypto_alloc_skcipher() - allocate symmetric key cipher handle
198 * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
200 * @type: specifies the type of the cipher
201 * @mask: specifies the mask for the cipher
203 * Allocate a cipher handle for an skcipher. The returned struct
204 * crypto_skcipher is the cipher handle that is required for any subsequent
205 * API invocation for that skcipher.
207 * Return: allocated cipher handle in case of success; IS_ERR() is true in case
208 * of an error, PTR_ERR() returns the error code.
210 struct crypto_skcipher *crypto_alloc_skcipher(const char *alg_name,
213 struct crypto_sync_skcipher *crypto_alloc_sync_skcipher(const char *alg_name,
216 static inline struct crypto_tfm *crypto_skcipher_tfm(
217 struct crypto_skcipher *tfm)
223 * crypto_free_skcipher() - zeroize and free cipher handle
224 * @tfm: cipher handle to be freed
226 * If @tfm is a NULL or error pointer, this function does nothing.
228 static inline void crypto_free_skcipher(struct crypto_skcipher *tfm)
230 crypto_destroy_tfm(tfm, crypto_skcipher_tfm(tfm));
233 static inline void crypto_free_sync_skcipher(struct crypto_sync_skcipher *tfm)
235 crypto_free_skcipher(&tfm->base);
239 * crypto_has_skcipher() - Search for the availability of an skcipher.
240 * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
242 * @type: specifies the type of the skcipher
243 * @mask: specifies the mask for the skcipher
245 * Return: true when the skcipher is known to the kernel crypto API; false
248 int crypto_has_skcipher(const char *alg_name, u32 type, u32 mask);
250 static inline const char *crypto_skcipher_driver_name(
251 struct crypto_skcipher *tfm)
253 return crypto_tfm_alg_driver_name(crypto_skcipher_tfm(tfm));
256 static inline struct skcipher_alg *crypto_skcipher_alg(
257 struct crypto_skcipher *tfm)
259 return container_of(crypto_skcipher_tfm(tfm)->__crt_alg,
260 struct skcipher_alg, base);
263 static inline unsigned int crypto_skcipher_alg_ivsize(struct skcipher_alg *alg)
269 * crypto_skcipher_ivsize() - obtain IV size
270 * @tfm: cipher handle
272 * The size of the IV for the skcipher referenced by the cipher handle is
273 * returned. This IV size may be zero if the cipher does not need an IV.
275 * Return: IV size in bytes
277 static inline unsigned int crypto_skcipher_ivsize(struct crypto_skcipher *tfm)
279 return crypto_skcipher_alg(tfm)->ivsize;
282 static inline unsigned int crypto_sync_skcipher_ivsize(
283 struct crypto_sync_skcipher *tfm)
285 return crypto_skcipher_ivsize(&tfm->base);
289 * crypto_skcipher_blocksize() - obtain block size of cipher
290 * @tfm: cipher handle
292 * The block size for the skcipher referenced with the cipher handle is
293 * returned. The caller may use that information to allocate appropriate
294 * memory for the data returned by the encryption or decryption operation
296 * Return: block size of cipher
298 static inline unsigned int crypto_skcipher_blocksize(
299 struct crypto_skcipher *tfm)
301 return crypto_tfm_alg_blocksize(crypto_skcipher_tfm(tfm));
304 static inline unsigned int crypto_skcipher_alg_chunksize(
305 struct skcipher_alg *alg)
307 return alg->chunksize;
311 * crypto_skcipher_chunksize() - obtain chunk size
312 * @tfm: cipher handle
314 * The block size is set to one for ciphers such as CTR. However,
315 * you still need to provide incremental updates in multiples of
316 * the underlying block size as the IV does not have sub-block
317 * granularity. This is known in this API as the chunk size.
319 * Return: chunk size in bytes
321 static inline unsigned int crypto_skcipher_chunksize(
322 struct crypto_skcipher *tfm)
324 return crypto_skcipher_alg_chunksize(crypto_skcipher_alg(tfm));
327 static inline unsigned int crypto_sync_skcipher_blocksize(
328 struct crypto_sync_skcipher *tfm)
330 return crypto_skcipher_blocksize(&tfm->base);
333 static inline unsigned int crypto_skcipher_alignmask(
334 struct crypto_skcipher *tfm)
336 return crypto_tfm_alg_alignmask(crypto_skcipher_tfm(tfm));
339 static inline u32 crypto_skcipher_get_flags(struct crypto_skcipher *tfm)
341 return crypto_tfm_get_flags(crypto_skcipher_tfm(tfm));
344 static inline void crypto_skcipher_set_flags(struct crypto_skcipher *tfm,
347 crypto_tfm_set_flags(crypto_skcipher_tfm(tfm), flags);
350 static inline void crypto_skcipher_clear_flags(struct crypto_skcipher *tfm,
353 crypto_tfm_clear_flags(crypto_skcipher_tfm(tfm), flags);
356 static inline u32 crypto_sync_skcipher_get_flags(
357 struct crypto_sync_skcipher *tfm)
359 return crypto_skcipher_get_flags(&tfm->base);
362 static inline void crypto_sync_skcipher_set_flags(
363 struct crypto_sync_skcipher *tfm, u32 flags)
365 crypto_skcipher_set_flags(&tfm->base, flags);
368 static inline void crypto_sync_skcipher_clear_flags(
369 struct crypto_sync_skcipher *tfm, u32 flags)
371 crypto_skcipher_clear_flags(&tfm->base, flags);
375 * crypto_skcipher_setkey() - set key for cipher
376 * @tfm: cipher handle
377 * @key: buffer holding the key
378 * @keylen: length of the key in bytes
380 * The caller provided key is set for the skcipher referenced by the cipher
383 * Note, the key length determines the cipher type. Many block ciphers implement
384 * different cipher modes depending on the key size, such as AES-128 vs AES-192
385 * vs. AES-256. When providing a 16 byte key for an AES cipher handle, AES-128
388 * Return: 0 if the setting of the key was successful; < 0 if an error occurred
390 int crypto_skcipher_setkey(struct crypto_skcipher *tfm,
391 const u8 *key, unsigned int keylen);
393 static inline int crypto_sync_skcipher_setkey(struct crypto_sync_skcipher *tfm,
394 const u8 *key, unsigned int keylen)
396 return crypto_skcipher_setkey(&tfm->base, key, keylen);
399 static inline unsigned int crypto_skcipher_min_keysize(
400 struct crypto_skcipher *tfm)
402 return crypto_skcipher_alg(tfm)->min_keysize;
405 static inline unsigned int crypto_skcipher_max_keysize(
406 struct crypto_skcipher *tfm)
408 return crypto_skcipher_alg(tfm)->max_keysize;
412 * crypto_skcipher_reqtfm() - obtain cipher handle from request
413 * @req: skcipher_request out of which the cipher handle is to be obtained
415 * Return the crypto_skcipher handle when furnishing an skcipher_request
418 * Return: crypto_skcipher handle
420 static inline struct crypto_skcipher *crypto_skcipher_reqtfm(
421 struct skcipher_request *req)
423 return __crypto_skcipher_cast(req->base.tfm);
426 static inline struct crypto_sync_skcipher *crypto_sync_skcipher_reqtfm(
427 struct skcipher_request *req)
429 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
431 return container_of(tfm, struct crypto_sync_skcipher, base);
435 * crypto_skcipher_encrypt() - encrypt plaintext
436 * @req: reference to the skcipher_request handle that holds all information
437 * needed to perform the cipher operation
439 * Encrypt plaintext data using the skcipher_request handle. That data
440 * structure and how it is filled with data is discussed with the
441 * skcipher_request_* functions.
443 * Return: 0 if the cipher operation was successful; < 0 if an error occurred
445 int crypto_skcipher_encrypt(struct skcipher_request *req);
448 * crypto_skcipher_decrypt() - decrypt ciphertext
449 * @req: reference to the skcipher_request handle that holds all information
450 * needed to perform the cipher operation
452 * Decrypt ciphertext data using the skcipher_request handle. That data
453 * structure and how it is filled with data is discussed with the
454 * skcipher_request_* functions.
456 * Return: 0 if the cipher operation was successful; < 0 if an error occurred
458 int crypto_skcipher_decrypt(struct skcipher_request *req);
461 * DOC: Symmetric Key Cipher Request Handle
463 * The skcipher_request data structure contains all pointers to data
464 * required for the symmetric key cipher operation. This includes the cipher
465 * handle (which can be used by multiple skcipher_request instances), pointer
466 * to plaintext and ciphertext, asynchronous callback function, etc. It acts
467 * as a handle to the skcipher_request_* API calls in a similar way as
468 * skcipher handle to the crypto_skcipher_* API calls.
472 * crypto_skcipher_reqsize() - obtain size of the request data structure
473 * @tfm: cipher handle
475 * Return: number of bytes
477 static inline unsigned int crypto_skcipher_reqsize(struct crypto_skcipher *tfm)
483 * skcipher_request_set_tfm() - update cipher handle reference in request
484 * @req: request handle to be modified
485 * @tfm: cipher handle that shall be added to the request handle
487 * Allow the caller to replace the existing skcipher handle in the request
488 * data structure with a different one.
490 static inline void skcipher_request_set_tfm(struct skcipher_request *req,
491 struct crypto_skcipher *tfm)
493 req->base.tfm = crypto_skcipher_tfm(tfm);
496 static inline void skcipher_request_set_sync_tfm(struct skcipher_request *req,
497 struct crypto_sync_skcipher *tfm)
499 skcipher_request_set_tfm(req, &tfm->base);
502 static inline struct skcipher_request *skcipher_request_cast(
503 struct crypto_async_request *req)
505 return container_of(req, struct skcipher_request, base);
509 * skcipher_request_alloc() - allocate request data structure
510 * @tfm: cipher handle to be registered with the request
511 * @gfp: memory allocation flag that is handed to kmalloc by the API call.
513 * Allocate the request data structure that must be used with the skcipher
514 * encrypt and decrypt API calls. During the allocation, the provided skcipher
515 * handle is registered in the request data structure.
517 * Return: allocated request handle in case of success, or NULL if out of memory
519 static inline struct skcipher_request *skcipher_request_alloc(
520 struct crypto_skcipher *tfm, gfp_t gfp)
522 struct skcipher_request *req;
524 req = kmalloc(sizeof(struct skcipher_request) +
525 crypto_skcipher_reqsize(tfm), gfp);
528 skcipher_request_set_tfm(req, tfm);
534 * skcipher_request_free() - zeroize and free request data structure
535 * @req: request data structure cipher handle to be freed
537 static inline void skcipher_request_free(struct skcipher_request *req)
539 kfree_sensitive(req);
542 static inline void skcipher_request_zero(struct skcipher_request *req)
544 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
546 memzero_explicit(req, sizeof(*req) + crypto_skcipher_reqsize(tfm));
550 * skcipher_request_set_callback() - set asynchronous callback function
551 * @req: request handle
552 * @flags: specify zero or an ORing of the flags
553 * CRYPTO_TFM_REQ_MAY_BACKLOG the request queue may back log and
554 * increase the wait queue beyond the initial maximum size;
555 * CRYPTO_TFM_REQ_MAY_SLEEP the request processing may sleep
556 * @compl: callback function pointer to be registered with the request handle
557 * @data: The data pointer refers to memory that is not used by the kernel
558 * crypto API, but provided to the callback function for it to use. Here,
559 * the caller can provide a reference to memory the callback function can
560 * operate on. As the callback function is invoked asynchronously to the
561 * related functionality, it may need to access data structures of the
562 * related functionality which can be referenced using this pointer. The
563 * callback function can access the memory via the "data" field in the
564 * crypto_async_request data structure provided to the callback function.
566 * This function allows setting the callback function that is triggered once the
567 * cipher operation completes.
569 * The callback function is registered with the skcipher_request handle and
570 * must comply with the following template::
572 * void callback_function(struct crypto_async_request *req, int error)
574 static inline void skcipher_request_set_callback(struct skcipher_request *req,
576 crypto_completion_t compl,
579 req->base.complete = compl;
580 req->base.data = data;
581 req->base.flags = flags;
585 * skcipher_request_set_crypt() - set data buffers
586 * @req: request handle
587 * @src: source scatter / gather list
588 * @dst: destination scatter / gather list
589 * @cryptlen: number of bytes to process from @src
590 * @iv: IV for the cipher operation which must comply with the IV size defined
591 * by crypto_skcipher_ivsize
593 * This function allows setting of the source data and destination data
594 * scatter / gather lists.
596 * For encryption, the source is treated as the plaintext and the
597 * destination is the ciphertext. For a decryption operation, the use is
598 * reversed - the source is the ciphertext and the destination is the plaintext.
600 static inline void skcipher_request_set_crypt(
601 struct skcipher_request *req,
602 struct scatterlist *src, struct scatterlist *dst,
603 unsigned int cryptlen, void *iv)
607 req->cryptlen = cryptlen;
611 #endif /* _CRYPTO_SKCIPHER_H */