summaryrefslogtreecommitdiff
path: root/include/linux/crypto.h
blob: b164da5e129e82aac45cc65fb7042fdbdfbf4fa7 (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
/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * Scatterlist Cryptographic API.
 *
 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
 * Copyright (c) 2002 David S. Miller (davem@redhat.com)
 * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>
 *
 * Portions derived from Cryptoapi, by Alexander Kjeldaas <astor@fast.no>
 * and Nettle, by Niels Möller.
 */
#ifndef _LINUX_CRYPTO_H
#define _LINUX_CRYPTO_H

#include <linux/completion.h>
#include <linux/refcount.h>
#include <linux/slab.h>
#include <linux/types.h>

/*
 * Algorithm masks and types.
 */
#define CRYPTO_ALG_TYPE_MASK		0x0000000f
#define CRYPTO_ALG_TYPE_CIPHER		0x00000001
#define CRYPTO_ALG_TYPE_COMPRESS	0x00000002
#define CRYPTO_ALG_TYPE_AEAD		0x00000003
#define CRYPTO_ALG_TYPE_LSKCIPHER	0x00000004
#define CRYPTO_ALG_TYPE_SKCIPHER	0x00000005
#define CRYPTO_ALG_TYPE_AKCIPHER	0x00000006
#define CRYPTO_ALG_TYPE_SIG		0x00000007
#define CRYPTO_ALG_TYPE_KPP		0x00000008
#define CRYPTO_ALG_TYPE_ACOMPRESS	0x0000000a
#define CRYPTO_ALG_TYPE_SCOMPRESS	0x0000000b
#define CRYPTO_ALG_TYPE_RNG		0x0000000c
#define CRYPTO_ALG_TYPE_HASH		0x0000000e
#define CRYPTO_ALG_TYPE_SHASH		0x0000000e
#define CRYPTO_ALG_TYPE_AHASH		0x0000000f

#define CRYPTO_ALG_TYPE_ACOMPRESS_MASK	0x0000000e

#define CRYPTO_ALG_LARVAL		0x00000010
#define CRYPTO_ALG_DEAD			0x00000020
#define CRYPTO_ALG_DYING		0x00000040
#define CRYPTO_ALG_ASYNC		0x00000080

/*
 * Set if the algorithm (or an algorithm which it uses) requires another
 * algorithm of the same type to handle corner cases.
 */
#define CRYPTO_ALG_NEED_FALLBACK	0x00000100

/*
 * Set if the algorithm has passed automated run-time testing.  Note that
 * if there is no run-time testing for a given algorithm it is considered
 * to have passed.
 */

#define CRYPTO_ALG_TESTED		0x00000400

/*
 * Set if the algorithm is an instance that is built from templates.
 */
#define CRYPTO_ALG_INSTANCE		0x00000800

/* Set this bit if the algorithm provided is hardware accelerated but
 * not available to userspace via instruction set or so.
 */
#define CRYPTO_ALG_KERN_DRIVER_ONLY	0x00001000

/*
 * Mark a cipher as a service implementation only usable by another
 * cipher and never by a normal user of the kernel crypto API
 */
#define CRYPTO_ALG_INTERNAL		0x00002000

/*
 * Set if the algorithm has a ->setkey() method but can be used without
 * calling it first, i.e. there is a default key.
 */
#define CRYPTO_ALG_OPTIONAL_KEY		0x00004000

/*
 * Don't trigger module loading
 */
#define CRYPTO_NOLOAD			0x00008000

/*
 * The algorithm may allocate memory during request processing, i.e. during
 * encryption, decryption, or hashing.  Users can request an algorithm with this
 * flag unset if they can't handle memory allocation failures.
 *
 * This flag is currently only implemented for algorithms of type "skcipher",
 * "aead", "ahash", "shash", and "cipher".  Algorithms of other types might not
 * have this flag set even if they allocate memory.
 *
 * In some edge cases, algorithms can allocate memory regardless of this flag.
 * To avoid these cases, users must obey the following usage constraints:
 *    skcipher:
 *	- The IV buffer and all scatterlist elements must be aligned to the
 *	  algorithm's alignmask.
 *	- If the data were to be divided into chunks of size
 *	  crypto_skcipher_walksize() (with any remainder going at the end), no
 *	  chunk can cross a page boundary or a scatterlist element boundary.
 *    aead:
 *	- The IV buffer and all scatterlist elements must be aligned to the
 *	  algorithm's alignmask.
 *	- The first scatterlist element must contain all the associated data,
 *	  and its pages must be !PageHighMem.
 *	- If the plaintext/ciphertext were to be divided into chunks of size
 *	  crypto_aead_walksize() (with the remainder going at the end), no chunk
 *	  can cross a page boundary or a scatterlist element boundary.
 *    ahash:
 *	- crypto_ahash_finup() must not be used unless the algorithm implements
 *	  ->finup() natively.
 */
#define CRYPTO_ALG_ALLOCATES_MEMORY	0x00010000

/*
 * Mark an algorithm as a service implementation only usable by a
 * template and never by a normal user of the kernel crypto API.
 * This is intended to be used by algorithms that are themselves
 * not FIPS-approved but may instead be used to implement parts of
 * a FIPS-approved algorithm (e.g., dh vs. ffdhe2048(dh)).
 */
#define CRYPTO_ALG_FIPS_INTERNAL	0x00020000

/*
 * Transform masks and values (for crt_flags).
 */
#define CRYPTO_TFM_NEED_KEY		0x00000001

#define CRYPTO_TFM_REQ_MASK		0x000fff00
#define CRYPTO_TFM_REQ_FORBID_WEAK_KEYS	0x00000100
#define CRYPTO_TFM_REQ_MAY_SLEEP	0x00000200
#define CRYPTO_TFM_REQ_MAY_BACKLOG	0x00000400

/*
 * Miscellaneous stuff.
 */
#define CRYPTO_MAX_ALG_NAME		128

/*
 * The macro CRYPTO_MINALIGN_ATTR (along with the void * type in the actual
 * declaration) is used to ensure that the crypto_tfm context structure is
 * aligned correctly for the given architecture so that there are no alignment
 * faults for C data types.  On architectures that support non-cache coherent
 * DMA, such as ARM or arm64, it also takes into account the minimal alignment
 * that is required to ensure that the context struct member does not share any
 * cachelines with the rest of the struct. This is needed to ensure that cache
 * maintenance for non-coherent DMA (cache invalidation in particular) does not
 * affect data that may be accessed by the CPU concurrently.
 */
#define CRYPTO_MINALIGN ARCH_KMALLOC_MINALIGN

#define CRYPTO_MINALIGN_ATTR __attribute__ ((__aligned__(CRYPTO_MINALIGN)))

struct crypto_tfm;
struct crypto_type;
struct module;

typedef void (*crypto_completion_t)(void *req, int err);

/**
 * DOC: Block Cipher Context Data Structures
 *
 * These data structures define the operating context for each block cipher
 * type.
 */

struct crypto_async_request {
	struct list_head list;
	crypto_completion_t complete;
	void *data;
	struct crypto_tfm *tfm;

	u32 flags;
};

/**
 * DOC: Block Cipher Algorithm Definitions
 *
 * These data structures define modular crypto algorithm implementations,
 * managed via crypto_register_alg() and crypto_unregister_alg().
 */

/**
 * struct cipher_alg - single-block symmetric ciphers definition
 * @cia_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/
 * @cia_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/
 * @cia_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.
 * @cia_encrypt: Encrypt a single block. This function is used to encrypt a
 *		 single block of data, which must be @cra_blocksize big. This
 *		 always operates on a full @cra_blocksize and it is not possible
 *		 to encrypt a block of smaller size. The supplied buffers must
 *		 therefore also be at least of @cra_blocksize size. Both the
 *		 input and output buffers are always aligned to @cra_alignmask.
 *		 In case either of the input or output buffer supplied by user
 *		 of the crypto API is not aligned to @cra_alignmask, the crypto
 *		 API will re-align the buffers. The re-alignment means that a
 *		 new buffer will be allocated, the data will be copied into the
 *		 new buffer, then the processing will happen on the new buffer,
 *		 then the data will be copied back into the original buffer and
 *		 finally the new buffer will be freed. 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.
 * @cia_decrypt: Decrypt a single block. This is a reverse counterpart to
 *		 @cia_encrypt, and the conditions are exactly the same.
 *
 * All fields are mandatory and must be filled.
 */
struct cipher_alg {
	unsigned int cia_min_keysize;
	unsigned int cia_max_keysize;
	int (*cia_setkey)(struct crypto_tfm *tfm, const u8 *key,
	                  unsigned int keylen);
	void (*cia_encrypt)(struct crypto_tfm *tfm, u8 *dst, const u8 *src);
	void (*cia_decrypt)(struct crypto_tfm *tfm, u8 *dst, const u8 *src);
};

/**
 * struct compress_alg - compression/decompression algorithm
 * @coa_compress: Compress a buffer of specified length, storing the resulting
 *		  data in the specified buffer. Return the length of the
 *		  compressed data in dlen.
 * @coa_decompress: Decompress the source buffer, storing the uncompressed
 *		    data in the specified buffer. The length of the data is
 *		    returned in dlen.
 *
 * All fields are mandatory.
 */
struct compress_alg {
	int (*coa_compress)(struct crypto_tfm *tfm, const u8 *src,
			    unsigned int slen, u8 *dst, unsigned int *dlen);
	int (*coa_decompress)(struct crypto_tfm *tfm, const u8 *src,
			      unsigned int slen, u8 *dst, unsigned int *dlen);
};

#define cra_cipher	cra_u.cipher
#define cra_compress	cra_u.compress

/**
 * struct crypto_alg - definition of a cryptograpic cipher algorithm
 * @cra_flags: Flags describing this transformation. See include/linux/crypto.h
 *	       CRYPTO_ALG_* flags for the flags which go in here. Those are
 *	       used for fine-tuning the description of the transformation
 *	       algorithm.
 * @cra_blocksize: Minimum block size of this transformation. The size in bytes
 *		   of the smallest possible unit which can be transformed with
 *		   this algorithm. The users must respect this value.
 *		   In case of HASH transformation, it is possible for a smaller
 *		   block than @cra_blocksize to be passed to the crypto API for
 *		   transformation, in case of any other transformation type, an
 * 		   error will be returned upon any attempt to transform smaller
 *		   than @cra_blocksize chunks.
 * @cra_ctxsize: Size of the operational context of the transformation. This
 *		 value informs the kernel crypto API about the memory size
 *		 needed to be allocated for the transformation context.
 * @cra_alignmask: For cipher, skcipher, lskcipher, and aead algorithms this is
 *		   1 less than the alignment, in bytes, that the algorithm
 *		   implementation requires for input and output buffers.  When
 *		   the crypto API is invoked with buffers that are not aligned
 *		   to this alignment, the crypto API automatically utilizes
 *		   appropriately aligned temporary buffers to comply with what
 *		   the algorithm needs.  (For scatterlists this happens only if
 *		   the algorithm uses the skcipher_walk helper functions.)  This
 *		   misalignment handling carries a performance penalty, so it is
 *		   preferred that algorithms do not set a nonzero alignmask.
 *		   Also, crypto API users may wish to allocate buffers aligned
 *		   to the alignmask of the algorithm being used, in order to
 *		   avoid the API having to realign them.  Note: the alignmask is
 *		   not supported for hash algorithms and is always 0 for them.
 * @cra_priority: Priority of this transformation implementation. In case
 *		  multiple transformations with same @cra_name are available to
 *		  the Crypto API, the kernel will use the one with highest
 *		  @cra_priority.
 * @cra_name: Generic name (usable by multiple implementations) of the
 *	      transformation algorithm. This is the name of the transformation
 *	      itself. This field is used by the kernel when looking up the
 *	      providers of particular transformation.
 * @cra_driver_name: Unique name of the transformation provider. This is the
 *		     name of the provider of the transformation. This can be any
 *		     arbitrary value, but in the usual case, this contains the
 *		     name of the chip or provider and the name of the
 *		     transformation algorithm.
 * @cra_type: Type of the cryptographic transformation. This is a pointer to
 *	      struct crypto_type, which implements callbacks common for all
 *	      transformation types. There are multiple options, such as
 *	      &crypto_skcipher_type, &crypto_ahash_type, &crypto_rng_type.
 *	      This field might be empty. In that case, there are no common
 *	      callbacks. This is the case for: cipher, compress, shash.
 * @cra_u: Callbacks implementing the transformation. This is a union of
 *	   multiple structures. Depending on the type of transformation selected
 *	   by @cra_type and @cra_flags above, the associated structure must be
 *	   filled with callbacks. This field might be empty. This is the case
 *	   for ahash, shash.
 * @cra_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.
 * @cra_exit: Deinitialize the cryptographic transformation object. This is a
 *	      counterpart to @cra_init, used to remove various changes set in
 *	      @cra_init.
 * @cra_u.cipher: Union member which contains a single-block symmetric cipher
 *		  definition. See @struct @cipher_alg.
 * @cra_u.compress: Union member which contains a (de)compression algorithm.
 *		    See @struct @compress_alg.
 * @cra_module: Owner of this transformation implementation. Set to THIS_MODULE
 * @cra_list: internally used
 * @cra_users: internally used
 * @cra_refcnt: internally used
 * @cra_destroy: internally used
 *
 * The struct crypto_alg describes a generic Crypto API algorithm and is common
 * for all of the transformations. Any variable not documented here shall not
 * be used by a cipher implementation as it is internal to the Crypto API.
 */
struct crypto_alg {
	struct list_head cra_list;
	struct list_head cra_users;

	u32 cra_flags;
	unsigned int cra_blocksize;
	unsigned int cra_ctxsize;
	unsigned int cra_alignmask;

	int cra_priority;
	refcount_t cra_refcnt;

	char cra_name[CRYPTO_MAX_ALG_NAME];
	char cra_driver_name[CRYPTO_MAX_ALG_NAME];

	const struct crypto_type *cra_type;

	union {
		struct cipher_alg cipher;
		struct compress_alg compress;
	} cra_u;

	int (*cra_init)(struct crypto_tfm *tfm);
	void (*cra_exit)(struct crypto_tfm *tfm);
	void (*cra_destroy)(struct crypto_alg *alg);
	
	struct module *cra_module;
} CRYPTO_MINALIGN_ATTR;

/*
 * A helper struct for waiting for completion of async crypto ops
 */
struct crypto_wait {
	struct completion completion;
	int err;
};

/*
 * Macro for declaring a crypto op async wait object on stack
 */
#define DECLARE_CRYPTO_WAIT(_wait) \
	struct crypto_wait _wait = { \
		COMPLETION_INITIALIZER_ONSTACK((_wait).completion), 0 }

/*
 * Async ops completion helper functioons
 */
void crypto_req_done(void *req, int err);

static inline int crypto_wait_req(int err, struct crypto_wait *wait)
{
	switch (err) {
	case -EINPROGRESS:
	case -EBUSY:
		wait_for_completion(&wait->completion);
		reinit_completion(&wait->completion);
		err = wait->err;
		break;
	}

	return err;
}

static inline void crypto_init_wait(struct crypto_wait *wait)
{
	init_completion(&wait->completion);
}

/*
 * Algorithm query interface.
 */
int crypto_has_alg(const char *name, u32 type, u32 mask);

/*
 * Transforms: user-instantiated objects which encapsulate algorithms
 * and core processing logic.  Managed via crypto_alloc_*() and
 * crypto_free_*(), as well as the various helpers below.
 */

struct crypto_tfm {
	refcount_t refcnt;

	u32 crt_flags;

	int node;
	
	void (*exit)(struct crypto_tfm *tfm);
	
	struct crypto_alg *__crt_alg;

	void *__crt_ctx[] CRYPTO_MINALIGN_ATTR;
};

struct crypto_comp {
	struct crypto_tfm base;
};

/* 
 * Transform user interface.
 */
 
struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask);
void crypto_destroy_tfm(void *mem, struct crypto_tfm *tfm);

static inline void crypto_free_tfm(struct crypto_tfm *tfm)
{
	return crypto_destroy_tfm(tfm, tfm);
}

/*
 * Transform helpers which query the underlying algorithm.
 */
static inline const char *crypto_tfm_alg_name(struct crypto_tfm *tfm)
{
	return tfm->__crt_alg->cra_name;
}

static inline const char *crypto_tfm_alg_driver_name(struct crypto_tfm *tfm)
{
	return tfm->__crt_alg->cra_driver_name;
}

static inline unsigned int crypto_tfm_alg_blocksize(struct crypto_tfm *tfm)
{
	return tfm->__crt_alg->cra_blocksize;
}

static inline unsigned int crypto_tfm_alg_alignmask(struct crypto_tfm *tfm)
{
	return tfm->__crt_alg->cra_alignmask;
}

static inline u32 crypto_tfm_get_flags(struct crypto_tfm *tfm)
{
	return tfm->crt_flags;
}

static inline void crypto_tfm_set_flags(struct crypto_tfm *tfm, u32 flags)
{
	tfm->crt_flags |= flags;
}

static inline void crypto_tfm_clear_flags(struct crypto_tfm *tfm, u32 flags)
{
	tfm->crt_flags &= ~flags;
}

static inline unsigned int crypto_tfm_ctx_alignment(void)
{
	struct crypto_tfm *tfm;
	return __alignof__(tfm->__crt_ctx);
}

static inline struct crypto_comp *__crypto_comp_cast(struct crypto_tfm *tfm)
{
	return (struct crypto_comp *)tfm;
}

static inline struct crypto_comp *crypto_alloc_comp(const char *alg_name,
						    u32 type, u32 mask)
{
	type &= ~CRYPTO_ALG_TYPE_MASK;
	type |= CRYPTO_ALG_TYPE_COMPRESS;
	mask |= CRYPTO_ALG_TYPE_MASK;

	return __crypto_comp_cast(crypto_alloc_base(alg_name, type, mask));
}

static inline struct crypto_tfm *crypto_comp_tfm(struct crypto_comp *tfm)
{
	return &tfm->base;
}

static inline void crypto_free_comp(struct crypto_comp *tfm)
{
	crypto_free_tfm(crypto_comp_tfm(tfm));
}

static inline int crypto_has_comp(const char *alg_name, u32 type, u32 mask)
{
	type &= ~CRYPTO_ALG_TYPE_MASK;
	type |= CRYPTO_ALG_TYPE_COMPRESS;
	mask |= CRYPTO_ALG_TYPE_MASK;

	return crypto_has_alg(alg_name, type, mask);
}

static inline const char *crypto_comp_name(struct crypto_comp *tfm)
{
	return crypto_tfm_alg_name(crypto_comp_tfm(tfm));
}

int crypto_comp_compress(struct crypto_comp *tfm,
			 const u8 *src, unsigned int slen,
			 u8 *dst, unsigned int *dlen);

int crypto_comp_decompress(struct crypto_comp *tfm,
			   const u8 *src, unsigned int slen,
			   u8 *dst, unsigned int *dlen);

#endif	/* _LINUX_CRYPTO_H */