xref: /linux/include/linux/crypto.h (revision 0ea5c948cb64bab5bc7a5516774eb8536f05aa0d)
1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3  * Scatterlist Cryptographic API.
4  *
5  * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
6  * Copyright (c) 2002 David S. Miller (davem@redhat.com)
7  * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>
8  *
9  * Portions derived from Cryptoapi, by Alexander Kjeldaas <astor@fast.no>
10  * and Nettle, by Niels Möller.
11  */
12 #ifndef _LINUX_CRYPTO_H
13 #define _LINUX_CRYPTO_H
14 
15 #include <linux/completion.h>
16 #include <linux/refcount.h>
17 #include <linux/slab.h>
18 #include <linux/types.h>
19 
20 /*
21  * Algorithm masks and types.
22  */
23 #define CRYPTO_ALG_TYPE_MASK		0x0000000f
24 #define CRYPTO_ALG_TYPE_CIPHER		0x00000001
25 #define CRYPTO_ALG_TYPE_COMPRESS	0x00000002
26 #define CRYPTO_ALG_TYPE_AEAD		0x00000003
27 #define CRYPTO_ALG_TYPE_LSKCIPHER	0x00000004
28 #define CRYPTO_ALG_TYPE_SKCIPHER	0x00000005
29 #define CRYPTO_ALG_TYPE_AKCIPHER	0x00000006
30 #define CRYPTO_ALG_TYPE_SIG		0x00000007
31 #define CRYPTO_ALG_TYPE_KPP		0x00000008
32 #define CRYPTO_ALG_TYPE_ACOMPRESS	0x0000000a
33 #define CRYPTO_ALG_TYPE_SCOMPRESS	0x0000000b
34 #define CRYPTO_ALG_TYPE_RNG		0x0000000c
35 #define CRYPTO_ALG_TYPE_HASH		0x0000000e
36 #define CRYPTO_ALG_TYPE_SHASH		0x0000000e
37 #define CRYPTO_ALG_TYPE_AHASH		0x0000000f
38 
39 #define CRYPTO_ALG_TYPE_ACOMPRESS_MASK	0x0000000e
40 
41 #define CRYPTO_ALG_LARVAL		0x00000010
42 #define CRYPTO_ALG_DEAD			0x00000020
43 #define CRYPTO_ALG_DYING		0x00000040
44 #define CRYPTO_ALG_ASYNC		0x00000080
45 
46 /*
47  * Set if the algorithm (or an algorithm which it uses) requires another
48  * algorithm of the same type to handle corner cases.
49  */
50 #define CRYPTO_ALG_NEED_FALLBACK	0x00000100
51 
52 /*
53  * Set if the algorithm has passed automated run-time testing.  Note that
54  * if there is no run-time testing for a given algorithm it is considered
55  * to have passed.
56  */
57 
58 #define CRYPTO_ALG_TESTED		0x00000400
59 
60 /*
61  * Set if the algorithm is an instance that is built from templates.
62  */
63 #define CRYPTO_ALG_INSTANCE		0x00000800
64 
65 /* Set this bit if the algorithm provided is hardware accelerated but
66  * not available to userspace via instruction set or so.
67  */
68 #define CRYPTO_ALG_KERN_DRIVER_ONLY	0x00001000
69 
70 /*
71  * Mark a cipher as a service implementation only usable by another
72  * cipher and never by a normal user of the kernel crypto API
73  */
74 #define CRYPTO_ALG_INTERNAL		0x00002000
75 
76 /*
77  * Set if the algorithm has a ->setkey() method but can be used without
78  * calling it first, i.e. there is a default key.
79  */
80 #define CRYPTO_ALG_OPTIONAL_KEY		0x00004000
81 
82 /*
83  * Don't trigger module loading
84  */
85 #define CRYPTO_NOLOAD			0x00008000
86 
87 /*
88  * The algorithm may allocate memory during request processing, i.e. during
89  * encryption, decryption, or hashing.  Users can request an algorithm with this
90  * flag unset if they can't handle memory allocation failures.
91  *
92  * This flag is currently only implemented for algorithms of type "skcipher",
93  * "aead", "ahash", "shash", and "cipher".  Algorithms of other types might not
94  * have this flag set even if they allocate memory.
95  *
96  * In some edge cases, algorithms can allocate memory regardless of this flag.
97  * To avoid these cases, users must obey the following usage constraints:
98  *    skcipher:
99  *	- The IV buffer and all scatterlist elements must be aligned to the
100  *	  algorithm's alignmask.
101  *	- If the data were to be divided into chunks of size
102  *	  crypto_skcipher_walksize() (with any remainder going at the end), no
103  *	  chunk can cross a page boundary or a scatterlist element boundary.
104  *    aead:
105  *	- The IV buffer and all scatterlist elements must be aligned to the
106  *	  algorithm's alignmask.
107  *	- The first scatterlist element must contain all the associated data,
108  *	  and its pages must be !PageHighMem.
109  *	- If the plaintext/ciphertext were to be divided into chunks of size
110  *	  crypto_aead_walksize() (with the remainder going at the end), no chunk
111  *	  can cross a page boundary or a scatterlist element boundary.
112  *    ahash:
113  *	- crypto_ahash_finup() must not be used unless the algorithm implements
114  *	  ->finup() natively.
115  */
116 #define CRYPTO_ALG_ALLOCATES_MEMORY	0x00010000
117 
118 /*
119  * Mark an algorithm as a service implementation only usable by a
120  * template and never by a normal user of the kernel crypto API.
121  * This is intended to be used by algorithms that are themselves
122  * not FIPS-approved but may instead be used to implement parts of
123  * a FIPS-approved algorithm (e.g., dh vs. ffdhe2048(dh)).
124  */
125 #define CRYPTO_ALG_FIPS_INTERNAL	0x00020000
126 
127 /*
128  * Transform masks and values (for crt_flags).
129  */
130 #define CRYPTO_TFM_NEED_KEY		0x00000001
131 
132 #define CRYPTO_TFM_REQ_MASK		0x000fff00
133 #define CRYPTO_TFM_REQ_FORBID_WEAK_KEYS	0x00000100
134 #define CRYPTO_TFM_REQ_MAY_SLEEP	0x00000200
135 #define CRYPTO_TFM_REQ_MAY_BACKLOG	0x00000400
136 
137 /*
138  * Miscellaneous stuff.
139  */
140 #define CRYPTO_MAX_ALG_NAME		128
141 
142 /*
143  * The macro CRYPTO_MINALIGN_ATTR (along with the void * type in the actual
144  * declaration) is used to ensure that the crypto_tfm context structure is
145  * aligned correctly for the given architecture so that there are no alignment
146  * faults for C data types.  On architectures that support non-cache coherent
147  * DMA, such as ARM or arm64, it also takes into account the minimal alignment
148  * that is required to ensure that the context struct member does not share any
149  * cachelines with the rest of the struct. This is needed to ensure that cache
150  * maintenance for non-coherent DMA (cache invalidation in particular) does not
151  * affect data that may be accessed by the CPU concurrently.
152  */
153 #define CRYPTO_MINALIGN ARCH_KMALLOC_MINALIGN
154 
155 #define CRYPTO_MINALIGN_ATTR __attribute__ ((__aligned__(CRYPTO_MINALIGN)))
156 
157 struct crypto_tfm;
158 struct crypto_type;
159 struct module;
160 
161 typedef void (*crypto_completion_t)(void *req, int err);
162 
163 /**
164  * DOC: Block Cipher Context Data Structures
165  *
166  * These data structures define the operating context for each block cipher
167  * type.
168  */
169 
170 struct crypto_async_request {
171 	struct list_head list;
172 	crypto_completion_t complete;
173 	void *data;
174 	struct crypto_tfm *tfm;
175 
176 	u32 flags;
177 };
178 
179 /**
180  * DOC: Block Cipher Algorithm Definitions
181  *
182  * These data structures define modular crypto algorithm implementations,
183  * managed via crypto_register_alg() and crypto_unregister_alg().
184  */
185 
186 /**
187  * struct cipher_alg - single-block symmetric ciphers definition
188  * @cia_min_keysize: Minimum key size supported by the transformation. This is
189  *		     the smallest key length supported by this transformation
190  *		     algorithm. This must be set to one of the pre-defined
191  *		     values as this is not hardware specific. Possible values
192  *		     for this field can be found via git grep "_MIN_KEY_SIZE"
193  *		     include/crypto/
194  * @cia_max_keysize: Maximum key size supported by the transformation. This is
195  *		    the largest key length supported by this transformation
196  *		    algorithm. This must be set to one of the pre-defined values
197  *		    as this is not hardware specific. Possible values for this
198  *		    field can be found via git grep "_MAX_KEY_SIZE"
199  *		    include/crypto/
200  * @cia_setkey: Set key for the transformation. This function is used to either
201  *	        program a supplied key into the hardware or store the key in the
202  *	        transformation context for programming it later. Note that this
203  *	        function does modify the transformation context. This function
204  *	        can be called multiple times during the existence of the
205  *	        transformation object, so one must make sure the key is properly
206  *	        reprogrammed into the hardware. This function is also
207  *	        responsible for checking the key length for validity.
208  * @cia_encrypt: Encrypt a single block. This function is used to encrypt a
209  *		 single block of data, which must be @cra_blocksize big. This
210  *		 always operates on a full @cra_blocksize and it is not possible
211  *		 to encrypt a block of smaller size. The supplied buffers must
212  *		 therefore also be at least of @cra_blocksize size. Both the
213  *		 input and output buffers are always aligned to @cra_alignmask.
214  *		 In case either of the input or output buffer supplied by user
215  *		 of the crypto API is not aligned to @cra_alignmask, the crypto
216  *		 API will re-align the buffers. The re-alignment means that a
217  *		 new buffer will be allocated, the data will be copied into the
218  *		 new buffer, then the processing will happen on the new buffer,
219  *		 then the data will be copied back into the original buffer and
220  *		 finally the new buffer will be freed. In case a software
221  *		 fallback was put in place in the @cra_init call, this function
222  *		 might need to use the fallback if the algorithm doesn't support
223  *		 all of the key sizes. In case the key was stored in
224  *		 transformation context, the key might need to be re-programmed
225  *		 into the hardware in this function. This function shall not
226  *		 modify the transformation context, as this function may be
227  *		 called in parallel with the same transformation object.
228  * @cia_decrypt: Decrypt a single block. This is a reverse counterpart to
229  *		 @cia_encrypt, and the conditions are exactly the same.
230  *
231  * All fields are mandatory and must be filled.
232  */
233 struct cipher_alg {
234 	unsigned int cia_min_keysize;
235 	unsigned int cia_max_keysize;
236 	int (*cia_setkey)(struct crypto_tfm *tfm, const u8 *key,
237 	                  unsigned int keylen);
238 	void (*cia_encrypt)(struct crypto_tfm *tfm, u8 *dst, const u8 *src);
239 	void (*cia_decrypt)(struct crypto_tfm *tfm, u8 *dst, const u8 *src);
240 };
241 
242 /**
243  * struct compress_alg - compression/decompression algorithm
244  * @coa_compress: Compress a buffer of specified length, storing the resulting
245  *		  data in the specified buffer. Return the length of the
246  *		  compressed data in dlen.
247  * @coa_decompress: Decompress the source buffer, storing the uncompressed
248  *		    data in the specified buffer. The length of the data is
249  *		    returned in dlen.
250  *
251  * All fields are mandatory.
252  */
253 struct compress_alg {
254 	int (*coa_compress)(struct crypto_tfm *tfm, const u8 *src,
255 			    unsigned int slen, u8 *dst, unsigned int *dlen);
256 	int (*coa_decompress)(struct crypto_tfm *tfm, const u8 *src,
257 			      unsigned int slen, u8 *dst, unsigned int *dlen);
258 };
259 
260 #define cra_cipher	cra_u.cipher
261 #define cra_compress	cra_u.compress
262 
263 /**
264  * struct crypto_alg - definition of a cryptograpic cipher algorithm
265  * @cra_flags: Flags describing this transformation. See include/linux/crypto.h
266  *	       CRYPTO_ALG_* flags for the flags which go in here. Those are
267  *	       used for fine-tuning the description of the transformation
268  *	       algorithm.
269  * @cra_blocksize: Minimum block size of this transformation. The size in bytes
270  *		   of the smallest possible unit which can be transformed with
271  *		   this algorithm. The users must respect this value.
272  *		   In case of HASH transformation, it is possible for a smaller
273  *		   block than @cra_blocksize to be passed to the crypto API for
274  *		   transformation, in case of any other transformation type, an
275  * 		   error will be returned upon any attempt to transform smaller
276  *		   than @cra_blocksize chunks.
277  * @cra_ctxsize: Size of the operational context of the transformation. This
278  *		 value informs the kernel crypto API about the memory size
279  *		 needed to be allocated for the transformation context.
280  * @cra_alignmask: For cipher, skcipher, lskcipher, and aead algorithms this is
281  *		   1 less than the alignment, in bytes, that the algorithm
282  *		   implementation requires for input and output buffers.  When
283  *		   the crypto API is invoked with buffers that are not aligned
284  *		   to this alignment, the crypto API automatically utilizes
285  *		   appropriately aligned temporary buffers to comply with what
286  *		   the algorithm needs.  (For scatterlists this happens only if
287  *		   the algorithm uses the skcipher_walk helper functions.)  This
288  *		   misalignment handling carries a performance penalty, so it is
289  *		   preferred that algorithms do not set a nonzero alignmask.
290  *		   Also, crypto API users may wish to allocate buffers aligned
291  *		   to the alignmask of the algorithm being used, in order to
292  *		   avoid the API having to realign them.  Note: the alignmask is
293  *		   not supported for hash algorithms and is always 0 for them.
294  * @cra_priority: Priority of this transformation implementation. In case
295  *		  multiple transformations with same @cra_name are available to
296  *		  the Crypto API, the kernel will use the one with highest
297  *		  @cra_priority.
298  * @cra_name: Generic name (usable by multiple implementations) of the
299  *	      transformation algorithm. This is the name of the transformation
300  *	      itself. This field is used by the kernel when looking up the
301  *	      providers of particular transformation.
302  * @cra_driver_name: Unique name of the transformation provider. This is the
303  *		     name of the provider of the transformation. This can be any
304  *		     arbitrary value, but in the usual case, this contains the
305  *		     name of the chip or provider and the name of the
306  *		     transformation algorithm.
307  * @cra_type: Type of the cryptographic transformation. This is a pointer to
308  *	      struct crypto_type, which implements callbacks common for all
309  *	      transformation types. There are multiple options, such as
310  *	      &crypto_skcipher_type, &crypto_ahash_type, &crypto_rng_type.
311  *	      This field might be empty. In that case, there are no common
312  *	      callbacks. This is the case for: cipher, compress, shash.
313  * @cra_u: Callbacks implementing the transformation. This is a union of
314  *	   multiple structures. Depending on the type of transformation selected
315  *	   by @cra_type and @cra_flags above, the associated structure must be
316  *	   filled with callbacks. This field might be empty. This is the case
317  *	   for ahash, shash.
318  * @cra_init: Initialize the cryptographic transformation object. This function
319  *	      is used to initialize the cryptographic transformation object.
320  *	      This function is called only once at the instantiation time, right
321  *	      after the transformation context was allocated. In case the
322  *	      cryptographic hardware has some special requirements which need to
323  *	      be handled by software, this function shall check for the precise
324  *	      requirement of the transformation and put any software fallbacks
325  *	      in place.
326  * @cra_exit: Deinitialize the cryptographic transformation object. This is a
327  *	      counterpart to @cra_init, used to remove various changes set in
328  *	      @cra_init.
329  * @cra_u.cipher: Union member which contains a single-block symmetric cipher
330  *		  definition. See @struct @cipher_alg.
331  * @cra_u.compress: Union member which contains a (de)compression algorithm.
332  *		    See @struct @compress_alg.
333  * @cra_module: Owner of this transformation implementation. Set to THIS_MODULE
334  * @cra_list: internally used
335  * @cra_users: internally used
336  * @cra_refcnt: internally used
337  * @cra_destroy: internally used
338  *
339  * The struct crypto_alg describes a generic Crypto API algorithm and is common
340  * for all of the transformations. Any variable not documented here shall not
341  * be used by a cipher implementation as it is internal to the Crypto API.
342  */
343 struct crypto_alg {
344 	struct list_head cra_list;
345 	struct list_head cra_users;
346 
347 	u32 cra_flags;
348 	unsigned int cra_blocksize;
349 	unsigned int cra_ctxsize;
350 	unsigned int cra_alignmask;
351 
352 	int cra_priority;
353 	refcount_t cra_refcnt;
354 
355 	char cra_name[CRYPTO_MAX_ALG_NAME];
356 	char cra_driver_name[CRYPTO_MAX_ALG_NAME];
357 
358 	const struct crypto_type *cra_type;
359 
360 	union {
361 		struct cipher_alg cipher;
362 		struct compress_alg compress;
363 	} cra_u;
364 
365 	int (*cra_init)(struct crypto_tfm *tfm);
366 	void (*cra_exit)(struct crypto_tfm *tfm);
367 	void (*cra_destroy)(struct crypto_alg *alg);
368 
369 	struct module *cra_module;
370 } CRYPTO_MINALIGN_ATTR;
371 
372 /*
373  * A helper struct for waiting for completion of async crypto ops
374  */
375 struct crypto_wait {
376 	struct completion completion;
377 	int err;
378 };
379 
380 /*
381  * Macro for declaring a crypto op async wait object on stack
382  */
383 #define DECLARE_CRYPTO_WAIT(_wait) \
384 	struct crypto_wait _wait = { \
385 		COMPLETION_INITIALIZER_ONSTACK((_wait).completion), 0 }
386 
387 /*
388  * Async ops completion helper functioons
389  */
390 void crypto_req_done(void *req, int err);
391 
crypto_wait_req(int err,struct crypto_wait * wait)392 static inline int crypto_wait_req(int err, struct crypto_wait *wait)
393 {
394 	switch (err) {
395 	case -EINPROGRESS:
396 	case -EBUSY:
397 		wait_for_completion(&wait->completion);
398 		reinit_completion(&wait->completion);
399 		err = wait->err;
400 		break;
401 	}
402 
403 	return err;
404 }
405 
crypto_init_wait(struct crypto_wait * wait)406 static inline void crypto_init_wait(struct crypto_wait *wait)
407 {
408 	init_completion(&wait->completion);
409 }
410 
411 /*
412  * Algorithm query interface.
413  */
414 int crypto_has_alg(const char *name, u32 type, u32 mask);
415 
416 /*
417  * Transforms: user-instantiated objects which encapsulate algorithms
418  * and core processing logic.  Managed via crypto_alloc_*() and
419  * crypto_free_*(), as well as the various helpers below.
420  */
421 
422 struct crypto_tfm {
423 	refcount_t refcnt;
424 
425 	u32 crt_flags;
426 
427 	int node;
428 
429 	void (*exit)(struct crypto_tfm *tfm);
430 
431 	struct crypto_alg *__crt_alg;
432 
433 	void *__crt_ctx[] CRYPTO_MINALIGN_ATTR;
434 };
435 
436 struct crypto_comp {
437 	struct crypto_tfm base;
438 };
439 
440 /*
441  * Transform user interface.
442  */
443 
444 struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask);
445 void crypto_destroy_tfm(void *mem, struct crypto_tfm *tfm);
446 
crypto_free_tfm(struct crypto_tfm * tfm)447 static inline void crypto_free_tfm(struct crypto_tfm *tfm)
448 {
449 	return crypto_destroy_tfm(tfm, tfm);
450 }
451 
452 /*
453  * Transform helpers which query the underlying algorithm.
454  */
crypto_tfm_alg_name(struct crypto_tfm * tfm)455 static inline const char *crypto_tfm_alg_name(struct crypto_tfm *tfm)
456 {
457 	return tfm->__crt_alg->cra_name;
458 }
459 
crypto_tfm_alg_driver_name(struct crypto_tfm * tfm)460 static inline const char *crypto_tfm_alg_driver_name(struct crypto_tfm *tfm)
461 {
462 	return tfm->__crt_alg->cra_driver_name;
463 }
464 
crypto_tfm_alg_blocksize(struct crypto_tfm * tfm)465 static inline unsigned int crypto_tfm_alg_blocksize(struct crypto_tfm *tfm)
466 {
467 	return tfm->__crt_alg->cra_blocksize;
468 }
469 
crypto_tfm_alg_alignmask(struct crypto_tfm * tfm)470 static inline unsigned int crypto_tfm_alg_alignmask(struct crypto_tfm *tfm)
471 {
472 	return tfm->__crt_alg->cra_alignmask;
473 }
474 
crypto_tfm_get_flags(struct crypto_tfm * tfm)475 static inline u32 crypto_tfm_get_flags(struct crypto_tfm *tfm)
476 {
477 	return tfm->crt_flags;
478 }
479 
crypto_tfm_set_flags(struct crypto_tfm * tfm,u32 flags)480 static inline void crypto_tfm_set_flags(struct crypto_tfm *tfm, u32 flags)
481 {
482 	tfm->crt_flags |= flags;
483 }
484 
crypto_tfm_clear_flags(struct crypto_tfm * tfm,u32 flags)485 static inline void crypto_tfm_clear_flags(struct crypto_tfm *tfm, u32 flags)
486 {
487 	tfm->crt_flags &= ~flags;
488 }
489 
crypto_tfm_ctx_alignment(void)490 static inline unsigned int crypto_tfm_ctx_alignment(void)
491 {
492 	struct crypto_tfm *tfm;
493 	return __alignof__(tfm->__crt_ctx);
494 }
495 
__crypto_comp_cast(struct crypto_tfm * tfm)496 static inline struct crypto_comp *__crypto_comp_cast(struct crypto_tfm *tfm)
497 {
498 	return (struct crypto_comp *)tfm;
499 }
500 
crypto_alloc_comp(const char * alg_name,u32 type,u32 mask)501 static inline struct crypto_comp *crypto_alloc_comp(const char *alg_name,
502 						    u32 type, u32 mask)
503 {
504 	type &= ~CRYPTO_ALG_TYPE_MASK;
505 	type |= CRYPTO_ALG_TYPE_COMPRESS;
506 	mask |= CRYPTO_ALG_TYPE_MASK;
507 
508 	return __crypto_comp_cast(crypto_alloc_base(alg_name, type, mask));
509 }
510 
crypto_comp_tfm(struct crypto_comp * tfm)511 static inline struct crypto_tfm *crypto_comp_tfm(struct crypto_comp *tfm)
512 {
513 	return &tfm->base;
514 }
515 
crypto_free_comp(struct crypto_comp * tfm)516 static inline void crypto_free_comp(struct crypto_comp *tfm)
517 {
518 	crypto_free_tfm(crypto_comp_tfm(tfm));
519 }
520 
crypto_has_comp(const char * alg_name,u32 type,u32 mask)521 static inline int crypto_has_comp(const char *alg_name, u32 type, u32 mask)
522 {
523 	type &= ~CRYPTO_ALG_TYPE_MASK;
524 	type |= CRYPTO_ALG_TYPE_COMPRESS;
525 	mask |= CRYPTO_ALG_TYPE_MASK;
526 
527 	return crypto_has_alg(alg_name, type, mask);
528 }
529 
crypto_comp_name(struct crypto_comp * tfm)530 static inline const char *crypto_comp_name(struct crypto_comp *tfm)
531 {
532 	return crypto_tfm_alg_name(crypto_comp_tfm(tfm));
533 }
534 
535 int crypto_comp_compress(struct crypto_comp *tfm,
536 			 const u8 *src, unsigned int slen,
537 			 u8 *dst, unsigned int *dlen);
538 
539 int crypto_comp_decompress(struct crypto_comp *tfm,
540 			   const u8 *src, unsigned int slen,
541 			   u8 *dst, unsigned int *dlen);
542 
543 #endif	/* _LINUX_CRYPTO_H */
544 
545