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