1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3 * Symmetric key ciphers.
4 *
5 * Copyright (c) 2007-2015 Herbert Xu <herbert@gondor.apana.org.au>
6 */
7
8 #ifndef _CRYPTO_SKCIPHER_H
9 #define _CRYPTO_SKCIPHER_H
10
11 #include <linux/crypto.h>
12 #include <linux/kernel.h>
13 #include <linux/slab.h>
14
15 /**
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
23 */
24 struct skcipher_request {
25 unsigned int cryptlen;
26
27 u8 *iv;
28
29 struct scatterlist *src;
30 struct scatterlist *dst;
31
32 struct crypto_async_request base;
33
34 void *__ctx[] CRYPTO_MINALIGN_ATTR;
35 };
36
37 struct crypto_skcipher {
38 int (*setkey)(struct crypto_skcipher *tfm, const u8 *key,
39 unsigned int keylen);
40 int (*encrypt)(struct skcipher_request *req);
41 int (*decrypt)(struct skcipher_request *req);
42
43 unsigned int ivsize;
44 unsigned int reqsize;
45 unsigned int keysize;
46
47 struct crypto_tfm base;
48 };
49
50 struct crypto_sync_skcipher {
51 struct crypto_skcipher base;
52 };
53
54 /**
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
96 * in place.
97 * @exit: Deinitialize the cryptographic transformation object. This is a
98 * counterpart to @init, used to remove various changes set in
99 * @init.
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.
108 *
109 * All fields except @ivsize are mandatory and must be filled.
110 */
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);
118
119 unsigned int min_keysize;
120 unsigned int max_keysize;
121 unsigned int ivsize;
122 unsigned int chunksize;
123 unsigned int walksize;
124
125 struct crypto_alg base;
126 };
127
128 #define MAX_SYNC_SKCIPHER_REQSIZE 384
129 /*
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.
132 */
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 == \
137 (typeof(tfm))1))) \
138 ] CRYPTO_MINALIGN_ATTR; \
139 struct skcipher_request *name = (void *)__##name##_desc
140
141 /**
142 * DOC: Symmetric Key Cipher API
143 *
144 * Symmetric key cipher API is used with the ciphers of type
145 * CRYPTO_ALG_TYPE_SKCIPHER (listed as type "skcipher" in /proc/crypto).
146 *
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.
154 *
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.
158 *
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.
169 */
170
171 static inline struct crypto_skcipher *__crypto_skcipher_cast(
172 struct crypto_tfm *tfm)
173 {
174 return container_of(tfm, struct crypto_skcipher, base);
175 }
176
177 /**
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
180 * skcipher cipher
181 * @type: specifies the type of the cipher
182 * @mask: specifies the mask for the cipher
183 *
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.
187 *
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.
190 */
191 struct crypto_skcipher *crypto_alloc_skcipher(const char *alg_name,
192 u32 type, u32 mask);
193
194 struct crypto_sync_skcipher *crypto_alloc_sync_skcipher(const char *alg_name,
195 u32 type, u32 mask);
196
197 static inline struct crypto_tfm *crypto_skcipher_tfm(
198 struct crypto_skcipher *tfm)
199 {
200 return &tfm->base;
201 }
202
203 /**
204 * crypto_free_skcipher() - zeroize and free cipher handle
205 * @tfm: cipher handle to be freed
206 */
207 static inline void crypto_free_skcipher(struct crypto_skcipher *tfm)
208 {
209 crypto_destroy_tfm(tfm, crypto_skcipher_tfm(tfm));
210 }
211
212 static inline void crypto_free_sync_skcipher(struct crypto_sync_skcipher *tfm)
213 {
214 crypto_free_skcipher(&tfm->base);
215 }
216
217 /**
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
220 * skcipher
221 * @type: specifies the type of the cipher
222 * @mask: specifies the mask for the cipher
223 *
224 * Return: true when the skcipher is known to the kernel crypto API; false
225 * otherwise
226 */
227 static inline int crypto_has_skcipher(const char *alg_name, u32 type,
228 u32 mask)
229 {
230 return crypto_has_alg(alg_name, crypto_skcipher_type(type),
231 crypto_skcipher_mask(mask));
232 }
233
234 /**
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
237 * skcipher
238 * @type: specifies the type of the skcipher
239 * @mask: specifies the mask for the skcipher
240 *
241 * Return: true when the skcipher is known to the kernel crypto API; false
242 * otherwise
243 */
244 int crypto_has_skcipher2(const char *alg_name, u32 type, u32 mask);
245
246 static inline const char *crypto_skcipher_driver_name(
247 struct crypto_skcipher *tfm)
248 {
249 return crypto_tfm_alg_driver_name(crypto_skcipher_tfm(tfm));
250 }
251
252 static inline struct skcipher_alg *crypto_skcipher_alg(
253 struct crypto_skcipher *tfm)
254 {
255 return container_of(crypto_skcipher_tfm(tfm)->__crt_alg,
256 struct skcipher_alg, base);
257 }
258
259 static inline unsigned int crypto_skcipher_alg_ivsize(struct skcipher_alg *alg)
260 {
261 if ((alg->base.cra_flags & CRYPTO_ALG_TYPE_MASK) ==
262 CRYPTO_ALG_TYPE_BLKCIPHER)
263 return alg->base.cra_blkcipher.ivsize;
264
265 if (alg->base.cra_ablkcipher.encrypt)
266 return alg->base.cra_ablkcipher.ivsize;
267
268 return alg->ivsize;
269 }
270
271 /**
272 * crypto_skcipher_ivsize() - obtain IV size
273 * @tfm: cipher handle
274 *
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.
277 *
278 * Return: IV size in bytes
279 */
280 static inline unsigned int crypto_skcipher_ivsize(struct crypto_skcipher *tfm)
281 {
282 return tfm->ivsize;
283 }
284
285 static inline unsigned int crypto_sync_skcipher_ivsize(
286 struct crypto_sync_skcipher *tfm)
287 {
288 return crypto_skcipher_ivsize(&tfm->base);
289 }
290
291 /**
292 * crypto_skcipher_blocksize() - obtain block size of cipher
293 * @tfm: cipher handle
294 *
295 * The block size for the skcipher referenced with the cipher handle is
296 * returned. The caller may use that information to allocate appropriate
297 * memory for the data returned by the encryption or decryption operation
298 *
299 * Return: block size of cipher
300 */
301 static inline unsigned int crypto_skcipher_blocksize(
302 struct crypto_skcipher *tfm)
303 {
304 return crypto_tfm_alg_blocksize(crypto_skcipher_tfm(tfm));
305 }
306
307 static inline unsigned int crypto_skcipher_alg_chunksize(
308 struct skcipher_alg *alg)
309 {
310 if ((alg->base.cra_flags & CRYPTO_ALG_TYPE_MASK) ==
311 CRYPTO_ALG_TYPE_BLKCIPHER)
312 return alg->base.cra_blocksize;
313
314 if (alg->base.cra_ablkcipher.encrypt)
315 return alg->base.cra_blocksize;
316
317 return alg->chunksize;
318 }
319
320 /**
321 * crypto_skcipher_chunksize() - obtain chunk size
322 * @tfm: cipher handle
323 *
324 * The block size is set to one for ciphers such as CTR. However,
325 * you still need to provide incremental updates in multiples of
326 * the underlying block size as the IV does not have sub-block
327 * granularity. This is known in this API as the chunk size.
328 *
329 * Return: chunk size in bytes
330 */
331 static inline unsigned int crypto_skcipher_chunksize(
332 struct crypto_skcipher *tfm)
333 {
334 return crypto_skcipher_alg_chunksize(crypto_skcipher_alg(tfm));
335 }
336
337 static inline unsigned int crypto_sync_skcipher_blocksize(
338 struct crypto_sync_skcipher *tfm)
339 {
340 return crypto_skcipher_blocksize(&tfm->base);
341 }
342
343 static inline unsigned int crypto_skcipher_alignmask(
344 struct crypto_skcipher *tfm)
345 {
346 return crypto_tfm_alg_alignmask(crypto_skcipher_tfm(tfm));
347 }
348
349 static inline u32 crypto_skcipher_get_flags(struct crypto_skcipher *tfm)
350 {
351 return crypto_tfm_get_flags(crypto_skcipher_tfm(tfm));
352 }
353
354 static inline void crypto_skcipher_set_flags(struct crypto_skcipher *tfm,
355 u32 flags)
356 {
357 crypto_tfm_set_flags(crypto_skcipher_tfm(tfm), flags);
358 }
359
360 static inline void crypto_skcipher_clear_flags(struct crypto_skcipher *tfm,
361 u32 flags)
362 {
363 crypto_tfm_clear_flags(crypto_skcipher_tfm(tfm), flags);
364 }
365
366 static inline u32 crypto_sync_skcipher_get_flags(
367 struct crypto_sync_skcipher *tfm)
368 {
369 return crypto_skcipher_get_flags(&tfm->base);
370 }
371
372 static inline void crypto_sync_skcipher_set_flags(
373 struct crypto_sync_skcipher *tfm, u32 flags)
374 {
375 crypto_skcipher_set_flags(&tfm->base, flags);
376 }
377
378 static inline void crypto_sync_skcipher_clear_flags(
379 struct crypto_sync_skcipher *tfm, u32 flags)
380 {
381 crypto_skcipher_clear_flags(&tfm->base, flags);
382 }
383
384 /**
385 * crypto_skcipher_setkey() - set key for cipher
386 * @tfm: cipher handle
387 * @key: buffer holding the key
388 * @keylen: length of the key in bytes
389 *
390 * The caller provided key is set for the skcipher referenced by the cipher
391 * handle.
392 *
393 * Note, the key length determines the cipher type. Many block ciphers implement
394 * different cipher modes depending on the key size, such as AES-128 vs AES-192
395 * vs. AES-256. When providing a 16 byte key for an AES cipher handle, AES-128
396 * is performed.
397 *
398 * Return: 0 if the setting of the key was successful; < 0 if an error occurred
399 */
400 static inline int crypto_skcipher_setkey(struct crypto_skcipher *tfm,
401 const u8 *key, unsigned int keylen)
402 {
403 return tfm->setkey(tfm, key, keylen);
404 }
405
406 static inline int crypto_sync_skcipher_setkey(struct crypto_sync_skcipher *tfm,
407 const u8 *key, unsigned int keylen)
408 {
409 return crypto_skcipher_setkey(&tfm->base, key, keylen);
410 }
411
412 static inline unsigned int crypto_skcipher_default_keysize(
413 struct crypto_skcipher *tfm)
414 {
415 return tfm->keysize;
416 }
417
418 /**
419 * crypto_skcipher_reqtfm() - obtain cipher handle from request
420 * @req: skcipher_request out of which the cipher handle is to be obtained
421 *
422 * Return the crypto_skcipher handle when furnishing an skcipher_request
423 * data structure.
424 *
425 * Return: crypto_skcipher handle
426 */
427 static inline struct crypto_skcipher *crypto_skcipher_reqtfm(
428 struct skcipher_request *req)
429 {
430 return __crypto_skcipher_cast(req->base.tfm);
431 }
432
433 static inline struct crypto_sync_skcipher *crypto_sync_skcipher_reqtfm(
434 struct skcipher_request *req)
435 {
436 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
437
438 return container_of(tfm, struct crypto_sync_skcipher, base);
439 }
440
441 /**
442 * crypto_skcipher_encrypt() - encrypt plaintext
443 * @req: reference to the skcipher_request handle that holds all information
444 * needed to perform the cipher operation
445 *
446 * Encrypt plaintext data using the skcipher_request handle. That data
447 * structure and how it is filled with data is discussed with the
448 * skcipher_request_* functions.
449 *
450 * Return: 0 if the cipher operation was successful; < 0 if an error occurred
451 */
452 int crypto_skcipher_encrypt(struct skcipher_request *req);
453
454 /**
455 * crypto_skcipher_decrypt() - decrypt ciphertext
456 * @req: reference to the skcipher_request handle that holds all information
457 * needed to perform the cipher operation
458 *
459 * Decrypt ciphertext data using the skcipher_request handle. That data
460 * structure and how it is filled with data is discussed with the
461 * skcipher_request_* functions.
462 *
463 * Return: 0 if the cipher operation was successful; < 0 if an error occurred
464 */
465 int crypto_skcipher_decrypt(struct skcipher_request *req);
466
467 /**
468 * DOC: Symmetric Key Cipher Request Handle
469 *
470 * The skcipher_request data structure contains all pointers to data
471 * required for the symmetric key cipher operation. This includes the cipher
472 * handle (which can be used by multiple skcipher_request instances), pointer
473 * to plaintext and ciphertext, asynchronous callback function, etc. It acts
474 * as a handle to the skcipher_request_* API calls in a similar way as
475 * skcipher handle to the crypto_skcipher_* API calls.
476 */
477
478 /**
479 * crypto_skcipher_reqsize() - obtain size of the request data structure
480 * @tfm: cipher handle
481 *
482 * Return: number of bytes
483 */
484 static inline unsigned int crypto_skcipher_reqsize(struct crypto_skcipher *tfm)
485 {
486 return tfm->reqsize;
487 }
488
489 /**
490 * skcipher_request_set_tfm() - update cipher handle reference in request
491 * @req: request handle to be modified
492 * @tfm: cipher handle that shall be added to the request handle
493 *
494 * Allow the caller to replace the existing skcipher handle in the request
495 * data structure with a different one.
496 */
497 static inline void skcipher_request_set_tfm(struct skcipher_request *req,
498 struct crypto_skcipher *tfm)
499 {
500 req->base.tfm = crypto_skcipher_tfm(tfm);
501 }
502
503 static inline void skcipher_request_set_sync_tfm(struct skcipher_request *req,
504 struct crypto_sync_skcipher *tfm)
505 {
506 skcipher_request_set_tfm(req, &tfm->base);
507 }
508
509 static inline struct skcipher_request *skcipher_request_cast(
510 struct crypto_async_request *req)
511 {
512 return container_of(req, struct skcipher_request, base);
513 }
514
515 /**
516 * skcipher_request_alloc() - allocate request data structure
517 * @tfm: cipher handle to be registered with the request
518 * @gfp: memory allocation flag that is handed to kmalloc by the API call.
519 *
520 * Allocate the request data structure that must be used with the skcipher
521 * encrypt and decrypt API calls. During the allocation, the provided skcipher
522 * handle is registered in the request data structure.
523 *
524 * Return: allocated request handle in case of success, or NULL if out of memory
525 */
526 static inline struct skcipher_request *skcipher_request_alloc(
527 struct crypto_skcipher *tfm, gfp_t gfp)
528 {
529 struct skcipher_request *req;
530
531 req = kmalloc(sizeof(struct skcipher_request) +
532 crypto_skcipher_reqsize(tfm), gfp);
533
534 if (likely(req))
535 skcipher_request_set_tfm(req, tfm);
536
537 return req;
538 }
539
540 /**
541 * skcipher_request_free() - zeroize and free request data structure
542 * @req: request data structure cipher handle to be freed
543 */
544 static inline void skcipher_request_free(struct skcipher_request *req)
545 {
546 kzfree(req);
547 }
548
549 static inline void skcipher_request_zero(struct skcipher_request *req)
550 {
551 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
552
553 memzero_explicit(req, sizeof(*req) + crypto_skcipher_reqsize(tfm));
554 }
555
556 /**
557 * skcipher_request_set_callback() - set asynchronous callback function
558 * @req: request handle
559 * @flags: specify zero or an ORing of the flags
560 * CRYPTO_TFM_REQ_MAY_BACKLOG the request queue may back log and
561 * increase the wait queue beyond the initial maximum size;
562 * CRYPTO_TFM_REQ_MAY_SLEEP the request processing may sleep
563 * @compl: callback function pointer to be registered with the request handle
564 * @data: The data pointer refers to memory that is not used by the kernel
565 * crypto API, but provided to the callback function for it to use. Here,
566 * the caller can provide a reference to memory the callback function can
567 * operate on. As the callback function is invoked asynchronously to the
568 * related functionality, it may need to access data structures of the
569 * related functionality which can be referenced using this pointer. The
570 * callback function can access the memory via the "data" field in the
571 * crypto_async_request data structure provided to the callback function.
572 *
573 * This function allows setting the callback function that is triggered once the
574 * cipher operation completes.
575 *
576 * The callback function is registered with the skcipher_request handle and
577 * must comply with the following template::
578 *
579 * void callback_function(struct crypto_async_request *req, int error)
580 */
581 static inline void skcipher_request_set_callback(struct skcipher_request *req,
582 u32 flags,
583 crypto_completion_t compl,
584 void *data)
585 {
586 req->base.complete = compl;
587 req->base.data = data;
588 req->base.flags = flags;
589 }
590
591 /**
592 * skcipher_request_set_crypt() - set data buffers
593 * @req: request handle
594 * @src: source scatter / gather list
595 * @dst: destination scatter / gather list
596 * @cryptlen: number of bytes to process from @src
597 * @iv: IV for the cipher operation which must comply with the IV size defined
598 * by crypto_skcipher_ivsize
599 *
600 * This function allows setting of the source data and destination data
601 * scatter / gather lists.
602 *
603 * For encryption, the source is treated as the plaintext and the
604 * destination is the ciphertext. For a decryption operation, the use is
605 * reversed - the source is the ciphertext and the destination is the plaintext.
606 */
607 static inline void skcipher_request_set_crypt(
608 struct skcipher_request *req,
609 struct scatterlist *src, struct scatterlist *dst,
610 unsigned int cryptlen, void *iv)
611 {
612 req->src = src;
613 req->dst = dst;
614 req->cryptlen = cryptlen;
615 req->iv = iv;
616 }
617
618 #endif /* _CRYPTO_SKCIPHER_H */
619