summaryrefslogtreecommitdiff
path: root/include/crypto/skcipher.h
blob: 080d1ba3611d8d924f82178c2fc4cad4d54b425a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * Symmetric key ciphers.
 * 
 * Copyright (c) 2007-2015 Herbert Xu <herbert@gondor.apana.org.au>
 */

#ifndef _CRYPTO_SKCIPHER_H
#define _CRYPTO_SKCIPHER_H

#include <linux/atomic.h>
#include <linux/container_of.h>
#include <linux/crypto.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/types.h>

struct scatterlist;

/**
 *	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
 *	@__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 crypto_skcipher {
	unsigned int reqsize;

	struct crypto_tfm base;
};

struct crypto_sync_skcipher {
	struct crypto_skcipher base;
};

/*
 * struct crypto_istat_cipher - statistics for cipher algorithm
 * @encrypt_cnt:	number of encrypt requests
 * @encrypt_tlen:	total data size handled by encrypt requests
 * @decrypt_cnt:	number of decrypt requests
 * @decrypt_tlen:	total data size handled by decrypt requests
 * @err_cnt:		number of error for cipher requests
 */
struct crypto_istat_cipher {
	atomic64_t encrypt_cnt;
	atomic64_t encrypt_tlen;
	atomic64_t decrypt_cnt;
	atomic64_t decrypt_tlen;
	atomic64_t err_cnt;
};

/**
 * 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.
 * @stat: Statistics for cipher algorithm
 * @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;

#ifdef CONFIG_CRYPTO_STATS
	struct crypto_istat_cipher stat;
#endif

	struct crypto_alg base;
};

#define MAX_SYNC_SKCIPHER_REQSIZE      384
/*
 * This performs a type-check against the "tfm" argument to make sure
 * all users have the correct skcipher tfm for doing on-stack requests.
 */
#define SYNC_SKCIPHER_REQUEST_ON_STACK(name, tfm) \
	char __##name##_desc[sizeof(struct skcipher_request) + \
			     MAX_SYNC_SKCIPHER_REQSIZE + \
			     (!(sizeof((struct crypto_sync_skcipher *)1 == \
				       (typeof(tfm))1))) \
			    ] 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);

struct crypto_sync_skcipher *crypto_alloc_sync_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));
}

static inline void crypto_free_sync_skcipher(struct crypto_sync_skcipher *tfm)
{
	crypto_free_skcipher(&tfm->base);
}

/**
 * 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 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_skcipher(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)
{
	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 crypto_skcipher_alg(tfm)->ivsize;
}

static inline unsigned int crypto_sync_skcipher_ivsize(
	struct crypto_sync_skcipher *tfm)
{
	return crypto_skcipher_ivsize(&tfm->base);
}

/**
 * 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_alg_chunksize(
	struct skcipher_alg *alg)
{
	return alg->chunksize;
}

/**
 * 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));
}

static inline unsigned int crypto_sync_skcipher_blocksize(
	struct crypto_sync_skcipher *tfm)
{
	return crypto_skcipher_blocksize(&tfm->base);
}

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);
}

static inline u32 crypto_sync_skcipher_get_flags(
	struct crypto_sync_skcipher *tfm)
{
	return crypto_skcipher_get_flags(&tfm->base);
}

static inline void crypto_sync_skcipher_set_flags(
	struct crypto_sync_skcipher *tfm, u32 flags)
{
	crypto_skcipher_set_flags(&tfm->base, flags);
}

static inline void crypto_sync_skcipher_clear_flags(
	struct crypto_sync_skcipher *tfm, u32 flags)
{
	crypto_skcipher_clear_flags(&tfm->base, 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
 */
int crypto_skcipher_setkey(struct crypto_skcipher *tfm,
			   const u8 *key, unsigned int keylen);

static inline int crypto_sync_skcipher_setkey(struct crypto_sync_skcipher *tfm,
					 const u8 *key, unsigned int keylen)
{
	return crypto_skcipher_setkey(&tfm->base, key, keylen);
}

static inline unsigned int crypto_skcipher_min_keysize(
	struct crypto_skcipher *tfm)
{
	return crypto_skcipher_alg(tfm)->min_keysize;
}

static inline unsigned int crypto_skcipher_max_keysize(
	struct crypto_skcipher *tfm)
{
	return crypto_skcipher_alg(tfm)->max_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);
}

static inline struct crypto_sync_skcipher *crypto_sync_skcipher_reqtfm(
	struct skcipher_request *req)
{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);

	return container_of(tfm, struct crypto_sync_skcipher, base);
}

/**
 * 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
 */
int crypto_skcipher_encrypt(struct skcipher_request *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
 */
int crypto_skcipher_decrypt(struct skcipher_request *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 void skcipher_request_set_sync_tfm(struct skcipher_request *req,
					    struct crypto_sync_skcipher *tfm)
{
	skcipher_request_set_tfm(req, &tfm->base);
}

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)
{
	kfree_sensitive(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 */