crypto.h

  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/errno.h>
 17#include <linux/refcount_types.h>
 18#include <linux/slab.h>
 19#include <linux/types.h>
 20
 21/*
 22 * Algorithm masks and types.
 23 */
 24#define CRYPTO_ALG_TYPE_MASK		0x0000000f
 25#define CRYPTO_ALG_TYPE_CIPHER		0x00000001
 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 data structure should be duplicated into
 54 * kmalloc memory before registration.  This is useful for hardware
 55 * that can be disconnected at will.  Do not use this if the data
 56 * structure is embedded into a bigger one.  Duplicate the overall
 57 * data structure in the driver in that case.
 58 */
 59#define CRYPTO_ALG_DUP_FIRST		0x00000200
 60
 61/*
 62 * Set if the algorithm has passed automated run-time testing.  Note that
 63 * if there is no run-time testing for a given algorithm it is considered
 64 * to have passed.
 65 */
 66
 67#define CRYPTO_ALG_TESTED		0x00000400
 68
 69/*
 70 * Set if the algorithm is an instance that is built from templates.
 71 */
 72#define CRYPTO_ALG_INSTANCE		0x00000800
 73
 74/* Set this bit if the algorithm provided is hardware accelerated but
 75 * not available to userspace via instruction set or so.
 76 */
 77#define CRYPTO_ALG_KERN_DRIVER_ONLY	0x00001000
 78
 79/*
 80 * Mark a cipher as a service implementation only usable by another
 81 * cipher and never by a normal user of the kernel crypto API
 82 */
 83#define CRYPTO_ALG_INTERNAL		0x00002000
 84
 85/*
 86 * Set if the algorithm has a ->setkey() method but can be used without
 87 * calling it first, i.e. there is a default key.
 88 */
 89#define CRYPTO_ALG_OPTIONAL_KEY		0x00004000
 90
 91/*
 92 * Don't trigger module loading
 93 */
 94#define CRYPTO_NOLOAD			0x00008000
 95
 96/*
 97 * The algorithm may allocate memory during request processing, i.e. during
 98 * encryption, decryption, or hashing.  Users can request an algorithm with this
 99 * flag unset if they can't handle memory allocation failures.
100 *
101 * This flag is currently only implemented for algorithms of type "skcipher",
102 * "aead", "ahash", "shash", and "cipher".  Algorithms of other types might not
103 * have this flag set even if they allocate memory.
104 *
105 * In some edge cases, algorithms can allocate memory regardless of this flag.
106 * To avoid these cases, users must obey the following usage constraints:
107 *    skcipher:
108 *	- The IV buffer and all scatterlist elements must be aligned to the
109 *	  algorithm's alignmask.
110 *	- If the data were to be divided into chunks of size
111 *	  crypto_skcipher_walksize() (with any remainder going at the end), no
112 *	  chunk can cross a page boundary or a scatterlist element boundary.
113 *    aead:
114 *	- The IV buffer and all scatterlist elements must be aligned to the
115 *	  algorithm's alignmask.
116 *	- The first scatterlist element must contain all the associated data,
117 *	  and its pages must be !PageHighMem.
118 *	- If the plaintext/ciphertext were to be divided into chunks of size
119 *	  crypto_aead_walksize() (with the remainder going at the end), no chunk
120 *	  can cross a page boundary or a scatterlist element boundary.
121 *    ahash:
122 *	- crypto_ahash_finup() must not be used unless the algorithm implements
123 *	  ->finup() natively.
124 */
125#define CRYPTO_ALG_ALLOCATES_MEMORY	0x00010000
126
127/*
128 * Mark an algorithm as a service implementation only usable by a
129 * template and never by a normal user of the kernel crypto API.
130 * This is intended to be used by algorithms that are themselves
131 * not FIPS-approved but may instead be used to implement parts of
132 * a FIPS-approved algorithm (e.g., dh vs. ffdhe2048(dh)).
133 */
134#define CRYPTO_ALG_FIPS_INTERNAL	0x00020000
135
136/* Set if the algorithm supports virtual addresses. */
137#define CRYPTO_ALG_REQ_VIRT		0x00040000
138
139/* Set if the algorithm cannot have a fallback (e.g., phmac). */
140#define CRYPTO_ALG_NO_FALLBACK		0x00080000
141
142/* The high bits 0xff000000 are reserved for type-specific flags. */
143
144/*
145 * Transform masks and values (for crt_flags).
146 */
147#define CRYPTO_TFM_NEED_KEY		0x00000001
148
149#define CRYPTO_TFM_REQ_MASK		0x000fff00
150#define CRYPTO_TFM_REQ_FORBID_WEAK_KEYS	0x00000100
151#define CRYPTO_TFM_REQ_MAY_SLEEP	0x00000200
152#define CRYPTO_TFM_REQ_MAY_BACKLOG	0x00000400
153#define CRYPTO_TFM_REQ_ON_STACK		0x00000800
154
155/*
156 * Miscellaneous stuff.
157 */
158#define CRYPTO_MAX_ALG_NAME		128
159
160/*
161 * The macro CRYPTO_MINALIGN_ATTR (along with the void * type in the actual
162 * declaration) is used to ensure that the crypto_tfm context structure is
163 * aligned correctly for the given architecture so that there are no alignment
164 * faults for C data types.  On architectures that support non-cache coherent
165 * DMA, such as ARM or arm64, it also takes into account the minimal alignment
166 * that is required to ensure that the context struct member does not share any
167 * cachelines with the rest of the struct. This is needed to ensure that cache
168 * maintenance for non-coherent DMA (cache invalidation in particular) does not
169 * affect data that may be accessed by the CPU concurrently.
170 */
171#define CRYPTO_MINALIGN ARCH_KMALLOC_MINALIGN
172
173#define CRYPTO_MINALIGN_ATTR __attribute__ ((__aligned__(CRYPTO_MINALIGN)))
174
175struct crypto_tfm;
176struct crypto_type;
177struct module;
178
179typedef void (*crypto_completion_t)(void *req, int err);
180
181/**
182 * DOC: Block Cipher Context Data Structures
183 *
184 * These data structures define the operating context for each block cipher
185 * type.
186 */
187
188struct crypto_async_request {
189	struct list_head list;
190	crypto_completion_t complete;
191	void *data;
192	struct crypto_tfm *tfm;
193
194	u32 flags;
195};
196
197/**
198 * DOC: Block Cipher Algorithm Definitions
199 *
200 * These data structures define modular crypto algorithm implementations,
201 * managed via crypto_register_alg() and crypto_unregister_alg().
202 */
203
204/**
205 * struct cipher_alg - single-block symmetric ciphers definition
206 * @cia_min_keysize: Minimum key size supported by the transformation. This is
207 *		     the smallest key length supported by this transformation
208 *		     algorithm. This must be set to one of the pre-defined
209 *		     values as this is not hardware specific. Possible values
210 *		     for this field can be found via git grep "_MIN_KEY_SIZE"
211 *		     include/crypto/
212 * @cia_max_keysize: Maximum key size supported by the transformation. This is
213 *		    the largest key length supported by this transformation
214 *		    algorithm. This must be set to one of the pre-defined values
215 *		    as this is not hardware specific. Possible values for this
216 *		    field can be found via git grep "_MAX_KEY_SIZE"
217 *		    include/crypto/
218 * @cia_setkey: Set key for the transformation. This function is used to either
219 *	        program a supplied key into the hardware or store the key in the
220 *	        transformation context for programming it later. Note that this
221 *	        function does modify the transformation context. This function
222 *	        can be called multiple times during the existence of the
223 *	        transformation object, so one must make sure the key is properly
224 *	        reprogrammed into the hardware. This function is also
225 *	        responsible for checking the key length for validity.
226 * @cia_encrypt: Encrypt a single block. This function is used to encrypt a
227 *		 single block of data, which must be @cra_blocksize big. This
228 *		 always operates on a full @cra_blocksize and it is not possible
229 *		 to encrypt a block of smaller size. The supplied buffers must
230 *		 therefore also be at least of @cra_blocksize size. Both the
231 *		 input and output buffers are always aligned to @cra_alignmask.
232 *		 In case either of the input or output buffer supplied by user
233 *		 of the crypto API is not aligned to @cra_alignmask, the crypto
234 *		 API will re-align the buffers. The re-alignment means that a
235 *		 new buffer will be allocated, the data will be copied into the
236 *		 new buffer, then the processing will happen on the new buffer,
237 *		 then the data will be copied back into the original buffer and
238 *		 finally the new buffer will be freed. In case a software
239 *		 fallback was put in place in the @cra_init call, this function
240 *		 might need to use the fallback if the algorithm doesn't support
241 *		 all of the key sizes. In case the key was stored in
242 *		 transformation context, the key might need to be re-programmed
243 *		 into the hardware in this function. This function shall not
244 *		 modify the transformation context, as this function may be
245 *		 called in parallel with the same transformation object.
246 * @cia_decrypt: Decrypt a single block. This is a reverse counterpart to
247 *		 @cia_encrypt, and the conditions are exactly the same.
248 *
249 * All fields are mandatory and must be filled.
250 */
251struct cipher_alg {
252	unsigned int cia_min_keysize;
253	unsigned int cia_max_keysize;
254	int (*cia_setkey)(struct crypto_tfm *tfm, const u8 *key,
255	                  unsigned int keylen);
256	void (*cia_encrypt)(struct crypto_tfm *tfm, u8 *dst, const u8 *src);
257	void (*cia_decrypt)(struct crypto_tfm *tfm, u8 *dst, const u8 *src);
258};
259
260#define cra_cipher	cra_u.cipher
261
262/**
263 * struct crypto_alg - definition of a cryptograpic cipher algorithm
264 * @cra_flags: Flags describing this transformation. See include/linux/crypto.h
265 *	       CRYPTO_ALG_* flags for the flags which go in here. Those are
266 *	       used for fine-tuning the description of the transformation
267 *	       algorithm.
268 * @cra_blocksize: Minimum block size of this transformation. The size in bytes
269 *		   of the smallest possible unit which can be transformed with
270 *		   this algorithm. The users must respect this value.
271 *		   In case of HASH transformation, it is possible for a smaller
272 *		   block than @cra_blocksize to be passed to the crypto API for
273 *		   transformation, in case of any other transformation type, an
274 * 		   error will be returned upon any attempt to transform smaller
275 *		   than @cra_blocksize chunks.
276 * @cra_ctxsize: Size of the operational context of the transformation. This
277 *		 value informs the kernel crypto API about the memory size
278 *		 needed to be allocated for the transformation context.
279 * @cra_alignmask: For cipher, skcipher, lskcipher, and aead algorithms this is
280 *		   1 less than the alignment, in bytes, that the algorithm
281 *		   implementation requires for input and output buffers.  When
282 *		   the crypto API is invoked with buffers that are not aligned
283 *		   to this alignment, the crypto API automatically utilizes
284 *		   appropriately aligned temporary buffers to comply with what
285 *		   the algorithm needs.  (For scatterlists this happens only if
286 *		   the algorithm uses the skcipher_walk helper functions.)  This
287 *		   misalignment handling carries a performance penalty, so it is
288 *		   preferred that algorithms do not set a nonzero alignmask.
289 *		   Also, crypto API users may wish to allocate buffers aligned
290 *		   to the alignmask of the algorithm being used, in order to
291 *		   avoid the API having to realign them.  Note: the alignmask is
292 *		   not supported for hash algorithms and is always 0 for them.
293 * @cra_reqsize: Size of the request context for this algorithm.
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.
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: Deprecated, do not use.
319 * @cra_exit: Deprecated, do not use.
320 * @cra_u.cipher: Union member which contains a single-block symmetric cipher
321 *		  definition. See @struct @cipher_alg.
322 * @cra_module: Owner of this transformation implementation. Set to THIS_MODULE
323 * @cra_list: internally used
324 * @cra_users: internally used
325 * @cra_refcnt: internally used
326 * @cra_destroy: internally used
327 *
328 * The struct crypto_alg describes a generic Crypto API algorithm and is common
329 * for all of the transformations. Any variable not documented here shall not
330 * be used by a cipher implementation as it is internal to the Crypto API.
331 */
332struct crypto_alg {
333	struct list_head cra_list;
334	struct list_head cra_users;
335
336	u32 cra_flags;
337	unsigned int cra_blocksize;
338	unsigned int cra_ctxsize;
339	unsigned int cra_alignmask;
340	unsigned int cra_reqsize;
341
342	int cra_priority;
343	refcount_t cra_refcnt;
344
345	char cra_name[CRYPTO_MAX_ALG_NAME];
346	char cra_driver_name[CRYPTO_MAX_ALG_NAME];
347
348	const struct crypto_type *cra_type;
349
350	union {
351		struct cipher_alg cipher;
352	} cra_u;
353
354	int (*cra_init)(struct crypto_tfm *tfm);
355	void (*cra_exit)(struct crypto_tfm *tfm);
356	void (*cra_destroy)(struct crypto_alg *alg);
357	
358	struct module *cra_module;
359} CRYPTO_MINALIGN_ATTR;
360
361/*
362 * A helper struct for waiting for completion of async crypto ops
363 */
364struct crypto_wait {
365	struct completion completion;
366	int err;
367};
368
369/*
370 * Macro for declaring a crypto op async wait object on stack
371 */
372#define DECLARE_CRYPTO_WAIT(_wait) \
373	struct crypto_wait _wait = { \
374		COMPLETION_INITIALIZER_ONSTACK((_wait).completion), 0 }
375
376/*
377 * Async ops completion helper functioons
378 */
379void crypto_req_done(void *req, int err);
380
381static inline int crypto_wait_req(int err, struct crypto_wait *wait)
382{
383	switch (err) {
384	case -EINPROGRESS:
385	case -EBUSY:
386		wait_for_completion(&wait->completion);
387		reinit_completion(&wait->completion);
388		err = wait->err;
389		break;
390	}
391
392	return err;
393}
394
395static inline void crypto_init_wait(struct crypto_wait *wait)
396{
397	init_completion(&wait->completion);
398}
399
400/*
401 * Algorithm query interface.
402 */
403int crypto_has_alg(const char *name, u32 type, u32 mask);
404
405/*
406 * Transforms: user-instantiated objects which encapsulate algorithms
407 * and core processing logic.  Managed via crypto_alloc_*() and
408 * crypto_free_*(), as well as the various helpers below.
409 */
410
411struct crypto_tfm {
412	refcount_t refcnt;
413
414	u32 crt_flags;
415
416	int node;
417
418	struct crypto_tfm *fb;
419
420	void (*exit)(struct crypto_tfm *tfm);
421
422	struct crypto_alg *__crt_alg;
423
424	void *__crt_ctx[] CRYPTO_MINALIGN_ATTR;
425};
426
427/* 
428 * Transform user interface.
429 */
430 
431struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask);
432void crypto_destroy_tfm(void *mem, struct crypto_tfm *tfm);
433
434static inline void crypto_free_tfm(struct crypto_tfm *tfm)
435{
436	return crypto_destroy_tfm(tfm, tfm);
437}
438
439/*
440 * Transform helpers which query the underlying algorithm.
441 */
442static inline const char *crypto_tfm_alg_name(struct crypto_tfm *tfm)
443{
444	return tfm->__crt_alg->cra_name;
445}
446
447static inline const char *crypto_tfm_alg_driver_name(struct crypto_tfm *tfm)
448{
449	return tfm->__crt_alg->cra_driver_name;
450}
451
452static inline unsigned int crypto_tfm_alg_blocksize(struct crypto_tfm *tfm)
453{
454	return tfm->__crt_alg->cra_blocksize;
455}
456
457static inline unsigned int crypto_tfm_alg_alignmask(struct crypto_tfm *tfm)
458{
459	return tfm->__crt_alg->cra_alignmask;
460}
461
462static inline unsigned int crypto_tfm_alg_reqsize(struct crypto_tfm *tfm)
463{
464	return tfm->__crt_alg->cra_reqsize;
465}
466
467static inline u32 crypto_tfm_get_flags(struct crypto_tfm *tfm)
468{
469	return tfm->crt_flags;
470}
471
472static inline void crypto_tfm_set_flags(struct crypto_tfm *tfm, u32 flags)
473{
474	tfm->crt_flags |= flags;
475}
476
477static inline void crypto_tfm_clear_flags(struct crypto_tfm *tfm, u32 flags)
478{
479	tfm->crt_flags &= ~flags;
480}
481
482static inline unsigned int crypto_tfm_ctx_alignment(void)
483{
484	struct crypto_tfm *tfm;
485	return __alignof__(tfm->__crt_ctx);
486}
487
488static inline bool crypto_tfm_is_async(struct crypto_tfm *tfm)
489{
490	return tfm->__crt_alg->cra_flags & CRYPTO_ALG_ASYNC;
491}
492
493static inline bool crypto_req_on_stack(struct crypto_async_request *req)
494{
495	return req->flags & CRYPTO_TFM_REQ_ON_STACK;
496}
497
498static inline void crypto_request_set_callback(
499	struct crypto_async_request *req, u32 flags,
500	crypto_completion_t compl, void *data)
501{
502	u32 keep = CRYPTO_TFM_REQ_ON_STACK;
503
504	req->complete = compl;
505	req->data = data;
506	req->flags &= keep;
507	req->flags |= flags & ~keep;
508}
509
510static inline void crypto_request_set_tfm(struct crypto_async_request *req,
511					  struct crypto_tfm *tfm)
512{
513	req->tfm = tfm;
514	req->flags &= ~CRYPTO_TFM_REQ_ON_STACK;
515}
516
517struct crypto_async_request *crypto_request_clone(
518	struct crypto_async_request *req, size_t total, gfp_t gfp);
519
520static inline void crypto_stack_request_init(struct crypto_async_request *req,
521					     struct crypto_tfm *tfm)
522{
523	req->flags = 0;
524	crypto_request_set_tfm(req, tfm);
525	req->flags |= CRYPTO_TFM_REQ_ON_STACK;
526}
527
528#endif	/* _LINUX_CRYPTO_H */
529