1/* SPDX-License-Identifier: GPL-2.0-or-later */
  2/*
  3 * AEAD: Authenticated Encryption with Associated Data
  4 * 
  5 * Copyright (c) 2007-2015 Herbert Xu <herbert@gondor.apana.org.au>
 
 
 
 
 
 
  6 */
  7
  8#ifndef _CRYPTO_AEAD_H
  9#define _CRYPTO_AEAD_H
 10
 11#include <linux/crypto.h>
 12#include <linux/kernel.h>
 13#include <linux/slab.h>
 14
 15/**
 16 * DOC: Authenticated Encryption With Associated Data (AEAD) Cipher API
 17 *
 18 * The AEAD cipher API is used with the ciphers of type CRYPTO_ALG_TYPE_AEAD
 19 * (listed as type "aead" in /proc/crypto)
 20 *
 21 * The most prominent examples for this type of encryption is GCM and CCM.
 22 * However, the kernel supports other types of AEAD ciphers which are defined
 23 * with the following cipher string:
 24 *
 25 *	authenc(keyed message digest, block cipher)
 26 *
 27 * For example: authenc(hmac(sha256), cbc(aes))
 28 *
 29 * The example code provided for the symmetric key cipher operation
 30 * applies here as well. Naturally all *skcipher* symbols must be exchanged
 31 * the *aead* pendants discussed in the following. In addition, for the AEAD
 32 * operation, the aead_request_set_ad function must be used to set the
 33 * pointer to the associated data memory location before performing the
 34 * encryption or decryption operation. In case of an encryption, the associated
 35 * data memory is filled during the encryption operation. For decryption, the
 36 * associated data memory must contain data that is used to verify the integrity
 37 * of the decrypted data. Another deviation from the asynchronous block cipher
 38 * operation is that the caller should explicitly check for -EBADMSG of the
 39 * crypto_aead_decrypt. That error indicates an authentication error, i.e.
 40 * a breach in the integrity of the message. In essence, that -EBADMSG error
 41 * code is the key bonus an AEAD cipher has over "standard" block chaining
 42 * modes.
 43 *
 44 * Memory Structure:
 45 *
 46 * The source scatterlist must contain the concatenation of
 47 * associated data || plaintext or ciphertext.
 48 *
 49 * The destination scatterlist has the same layout, except that the plaintext
 50 * (resp. ciphertext) will grow (resp. shrink) by the authentication tag size
 51 * during encryption (resp. decryption).
 52 *
 53 * In-place encryption/decryption is enabled by using the same scatterlist
 54 * pointer for both the source and destination.
 55 *
 56 * Even in the out-of-place case, space must be reserved in the destination for
 57 * the associated data, even though it won't be written to.  This makes the
 58 * in-place and out-of-place cases more consistent.  It is permissible for the
 59 * "destination" associated data to alias the "source" associated data.
 60 *
 61 * As with the other scatterlist crypto APIs, zero-length scatterlist elements
 62 * are not allowed in the used part of the scatterlist.  Thus, if there is no
 63 * associated data, the first element must point to the plaintext/ciphertext.
 64 *
 65 * To meet the needs of IPsec, a special quirk applies to rfc4106, rfc4309,
 66 * rfc4543, and rfc7539esp ciphers.  For these ciphers, the final 'ivsize' bytes
 67 * of the associated data buffer must contain a second copy of the IV.  This is
 68 * in addition to the copy passed to aead_request_set_crypt().  These two IV
 69 * copies must not differ; different implementations of the same algorithm may
 70 * behave differently in that case.  Note that the algorithm might not actually
 71 * treat the IV as associated data; nevertheless the length passed to
 72 * aead_request_set_ad() must include it.
 73 */
 74
 75struct crypto_aead;
 76
 77/**
 78 *	struct aead_request - AEAD request
 79 *	@base: Common attributes for async crypto requests
 80 *	@assoclen: Length in bytes of associated data for authentication
 81 *	@cryptlen: Length of data to be encrypted or decrypted
 82 *	@iv: Initialisation vector
 83 *	@src: Source data
 84 *	@dst: Destination data
 85 *	@__ctx: Start of private context data
 86 */
 87struct aead_request {
 88	struct crypto_async_request base;
 89
 90	unsigned int assoclen;
 91	unsigned int cryptlen;
 92
 93	u8 *iv;
 94
 95	struct scatterlist *src;
 96	struct scatterlist *dst;
 97
 98	void *__ctx[] CRYPTO_MINALIGN_ATTR;
 99};
100
101/**
102 * struct aead_alg - AEAD cipher definition
103 * @maxauthsize: Set the maximum authentication tag size supported by the
104 *		 transformation. A transformation may support smaller tag sizes.
105 *		 As the authentication tag is a message digest to ensure the
106 *		 integrity of the encrypted data, a consumer typically wants the
107 *		 largest authentication tag possible as defined by this
108 *		 variable.
109 * @setauthsize: Set authentication size for the AEAD transformation. This
110 *		 function is used to specify the consumer requested size of the
111 * 		 authentication tag to be either generated by the transformation
112 *		 during encryption or the size of the authentication tag to be
113 *		 supplied during the decryption operation. This function is also
114 *		 responsible for checking the authentication tag size for
115 *		 validity.
116 * @setkey: see struct skcipher_alg
117 * @encrypt: see struct skcipher_alg
118 * @decrypt: see struct skcipher_alg
 
119 * @ivsize: see struct skcipher_alg
120 * @chunksize: see struct skcipher_alg
121 * @init: Initialize the cryptographic transformation object. This function
122 *	  is used to initialize the cryptographic transformation object.
123 *	  This function is called only once at the instantiation time, right
124 *	  after the transformation context was allocated. In case the
125 *	  cryptographic hardware has some special requirements which need to
126 *	  be handled by software, this function shall check for the precise
127 *	  requirement of the transformation and put any software fallbacks
128 *	  in place.
129 * @exit: Deinitialize the cryptographic transformation object. This is a
130 *	  counterpart to @init, used to remove various changes set in
131 *	  @init.
132 * @base: Definition of a generic crypto cipher algorithm.
133 *
134 * All fields except @ivsize is mandatory and must be filled.
135 */
136struct aead_alg {
137	int (*setkey)(struct crypto_aead *tfm, const u8 *key,
138	              unsigned int keylen);
139	int (*setauthsize)(struct crypto_aead *tfm, unsigned int authsize);
140	int (*encrypt)(struct aead_request *req);
141	int (*decrypt)(struct aead_request *req);
142	int (*init)(struct crypto_aead *tfm);
143	void (*exit)(struct crypto_aead *tfm);
144
 
 
145	unsigned int ivsize;
146	unsigned int maxauthsize;
147	unsigned int chunksize;
148
149	struct crypto_alg base;
150};
151
152struct crypto_aead {
153	unsigned int authsize;
154	unsigned int reqsize;
155
156	struct crypto_tfm base;
157};
158
159static inline struct crypto_aead *__crypto_aead_cast(struct crypto_tfm *tfm)
160{
161	return container_of(tfm, struct crypto_aead, base);
162}
163
164/**
165 * crypto_alloc_aead() - allocate AEAD cipher handle
166 * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
167 *	     AEAD cipher
168 * @type: specifies the type of the cipher
169 * @mask: specifies the mask for the cipher
170 *
171 * Allocate a cipher handle for an AEAD. The returned struct
172 * crypto_aead is the cipher handle that is required for any subsequent
173 * API invocation for that AEAD.
174 *
175 * Return: allocated cipher handle in case of success; IS_ERR() is true in case
176 *	   of an error, PTR_ERR() returns the error code.
177 */
178struct crypto_aead *crypto_alloc_aead(const char *alg_name, u32 type, u32 mask);
179
180static inline struct crypto_tfm *crypto_aead_tfm(struct crypto_aead *tfm)
181{
182	return &tfm->base;
183}
184
185/**
186 * crypto_free_aead() - zeroize and free aead handle
187 * @tfm: cipher handle to be freed
188 *
189 * If @tfm is a NULL or error pointer, this function does nothing.
190 */
191static inline void crypto_free_aead(struct crypto_aead *tfm)
192{
193	crypto_destroy_tfm(tfm, crypto_aead_tfm(tfm));
194}
195
196static inline const char *crypto_aead_driver_name(struct crypto_aead *tfm)
197{
198	return crypto_tfm_alg_driver_name(crypto_aead_tfm(tfm));
199}
200
201static inline struct aead_alg *crypto_aead_alg(struct crypto_aead *tfm)
202{
203	return container_of(crypto_aead_tfm(tfm)->__crt_alg,
204			    struct aead_alg, base);
205}
206
207static inline unsigned int crypto_aead_alg_ivsize(struct aead_alg *alg)
208{
209	return alg->ivsize;
210}
211
212/**
213 * crypto_aead_ivsize() - obtain IV size
214 * @tfm: cipher handle
215 *
216 * The size of the IV for the aead referenced by the cipher handle is
217 * returned. This IV size may be zero if the cipher does not need an IV.
218 *
219 * Return: IV size in bytes
220 */
221static inline unsigned int crypto_aead_ivsize(struct crypto_aead *tfm)
222{
223	return crypto_aead_alg_ivsize(crypto_aead_alg(tfm));
224}
225
226/**
227 * crypto_aead_authsize() - obtain maximum authentication data size
228 * @tfm: cipher handle
229 *
230 * The maximum size of the authentication data for the AEAD cipher referenced
231 * by the AEAD cipher handle is returned. The authentication data size may be
232 * zero if the cipher implements a hard-coded maximum.
233 *
234 * The authentication data may also be known as "tag value".
235 *
236 * Return: authentication data size / tag size in bytes
237 */
238static inline unsigned int crypto_aead_authsize(struct crypto_aead *tfm)
239{
240	return tfm->authsize;
241}
242
243static inline unsigned int crypto_aead_alg_maxauthsize(struct aead_alg *alg)
244{
245	return alg->maxauthsize;
246}
247
248static inline unsigned int crypto_aead_maxauthsize(struct crypto_aead *aead)
249{
250	return crypto_aead_alg_maxauthsize(crypto_aead_alg(aead));
251}
252
253/**
254 * crypto_aead_blocksize() - obtain block size of cipher
255 * @tfm: cipher handle
256 *
257 * The block size for the AEAD referenced with the cipher handle is returned.
258 * The caller may use that information to allocate appropriate memory for the
259 * data returned by the encryption or decryption operation
260 *
261 * Return: block size of cipher
262 */
263static inline unsigned int crypto_aead_blocksize(struct crypto_aead *tfm)
264{
265	return crypto_tfm_alg_blocksize(crypto_aead_tfm(tfm));
266}
267
268static inline unsigned int crypto_aead_alignmask(struct crypto_aead *tfm)
269{
270	return crypto_tfm_alg_alignmask(crypto_aead_tfm(tfm));
271}
272
273static inline u32 crypto_aead_get_flags(struct crypto_aead *tfm)
274{
275	return crypto_tfm_get_flags(crypto_aead_tfm(tfm));
276}
277
278static inline void crypto_aead_set_flags(struct crypto_aead *tfm, u32 flags)
279{
280	crypto_tfm_set_flags(crypto_aead_tfm(tfm), flags);
281}
282
283static inline void crypto_aead_clear_flags(struct crypto_aead *tfm, u32 flags)
284{
285	crypto_tfm_clear_flags(crypto_aead_tfm(tfm), flags);
286}
287
288/**
289 * crypto_aead_setkey() - set key for cipher
290 * @tfm: cipher handle
291 * @key: buffer holding the key
292 * @keylen: length of the key in bytes
293 *
294 * The caller provided key is set for the AEAD referenced by the cipher
295 * handle.
296 *
297 * Note, the key length determines the cipher type. Many block ciphers implement
298 * different cipher modes depending on the key size, such as AES-128 vs AES-192
299 * vs. AES-256. When providing a 16 byte key for an AES cipher handle, AES-128
300 * is performed.
301 *
302 * Return: 0 if the setting of the key was successful; < 0 if an error occurred
303 */
304int crypto_aead_setkey(struct crypto_aead *tfm,
305		       const u8 *key, unsigned int keylen);
306
307/**
308 * crypto_aead_setauthsize() - set authentication data size
309 * @tfm: cipher handle
310 * @authsize: size of the authentication data / tag in bytes
311 *
312 * Set the authentication data size / tag size. AEAD requires an authentication
313 * tag (or MAC) in addition to the associated data.
314 *
315 * Return: 0 if the setting of the key was successful; < 0 if an error occurred
316 */
317int crypto_aead_setauthsize(struct crypto_aead *tfm, unsigned int authsize);
318
319static inline struct crypto_aead *crypto_aead_reqtfm(struct aead_request *req)
320{
321	return __crypto_aead_cast(req->base.tfm);
322}
323
324/**
325 * crypto_aead_encrypt() - encrypt plaintext
326 * @req: reference to the aead_request handle that holds all information
327 *	 needed to perform the cipher operation
328 *
329 * Encrypt plaintext data using the aead_request handle. That data structure
330 * and how it is filled with data is discussed with the aead_request_*
331 * functions.
332 *
333 * IMPORTANT NOTE The encryption operation creates the authentication data /
334 *		  tag. That data is concatenated with the created ciphertext.
335 *		  The ciphertext memory size is therefore the given number of
336 *		  block cipher blocks + the size defined by the
337 *		  crypto_aead_setauthsize invocation. The caller must ensure
338 *		  that sufficient memory is available for the ciphertext and
339 *		  the authentication tag.
340 *
341 * Return: 0 if the cipher operation was successful; < 0 if an error occurred
342 */
343int crypto_aead_encrypt(struct aead_request *req);
 
 
 
 
 
 
 
 
344
345/**
346 * crypto_aead_decrypt() - decrypt ciphertext
347 * @req: reference to the aead_request handle that holds all information
348 *	 needed to perform the cipher operation
349 *
350 * Decrypt ciphertext data using the aead_request handle. That data structure
351 * and how it is filled with data is discussed with the aead_request_*
352 * functions.
353 *
354 * IMPORTANT NOTE The caller must concatenate the ciphertext followed by the
355 *		  authentication data / tag. That authentication data / tag
356 *		  must have the size defined by the crypto_aead_setauthsize
357 *		  invocation.
358 *
359 *
360 * Return: 0 if the cipher operation was successful; -EBADMSG: The AEAD
361 *	   cipher operation performs the authentication of the data during the
362 *	   decryption operation. Therefore, the function returns this error if
363 *	   the authentication of the ciphertext was unsuccessful (i.e. the
364 *	   integrity of the ciphertext or the associated data was violated);
365 *	   < 0 if an error occurred.
366 */
367int crypto_aead_decrypt(struct aead_request *req);
 
 
 
 
 
 
 
 
 
 
 
368
369/**
370 * DOC: Asynchronous AEAD Request Handle
371 *
372 * The aead_request data structure contains all pointers to data required for
373 * the AEAD cipher operation. This includes the cipher handle (which can be
374 * used by multiple aead_request instances), pointer to plaintext and
375 * ciphertext, asynchronous callback function, etc. It acts as a handle to the
376 * aead_request_* API calls in a similar way as AEAD handle to the
377 * crypto_aead_* API calls.
378 */
379
380/**
381 * crypto_aead_reqsize() - obtain size of the request data structure
382 * @tfm: cipher handle
383 *
384 * Return: number of bytes
385 */
386static inline unsigned int crypto_aead_reqsize(struct crypto_aead *tfm)
387{
388	return tfm->reqsize;
389}
390
391/**
392 * aead_request_set_tfm() - update cipher handle reference in request
393 * @req: request handle to be modified
394 * @tfm: cipher handle that shall be added to the request handle
395 *
396 * Allow the caller to replace the existing aead handle in the request
397 * data structure with a different one.
398 */
399static inline void aead_request_set_tfm(struct aead_request *req,
400					struct crypto_aead *tfm)
401{
402	req->base.tfm = crypto_aead_tfm(tfm);
403}
404
405/**
406 * aead_request_alloc() - allocate request data structure
407 * @tfm: cipher handle to be registered with the request
408 * @gfp: memory allocation flag that is handed to kmalloc by the API call.
409 *
410 * Allocate the request data structure that must be used with the AEAD
411 * encrypt and decrypt API calls. During the allocation, the provided aead
412 * handle is registered in the request data structure.
413 *
414 * Return: allocated request handle in case of success, or NULL if out of memory
415 */
416static inline struct aead_request *aead_request_alloc(struct crypto_aead *tfm,
417						      gfp_t gfp)
418{
419	struct aead_request *req;
420
421	req = kmalloc(sizeof(*req) + crypto_aead_reqsize(tfm), gfp);
422
423	if (likely(req))
424		aead_request_set_tfm(req, tfm);
425
426	return req;
427}
428
429/**
430 * aead_request_free() - zeroize and free request data structure
431 * @req: request data structure cipher handle to be freed
432 */
433static inline void aead_request_free(struct aead_request *req)
434{
435	kfree_sensitive(req);
436}
437
438/**
439 * aead_request_set_callback() - set asynchronous callback function
440 * @req: request handle
441 * @flags: specify zero or an ORing of the flags
442 *	   CRYPTO_TFM_REQ_MAY_BACKLOG the request queue may back log and
443 *	   increase the wait queue beyond the initial maximum size;
444 *	   CRYPTO_TFM_REQ_MAY_SLEEP the request processing may sleep
445 * @compl: callback function pointer to be registered with the request handle
446 * @data: The data pointer refers to memory that is not used by the kernel
447 *	  crypto API, but provided to the callback function for it to use. Here,
448 *	  the caller can provide a reference to memory the callback function can
449 *	  operate on. As the callback function is invoked asynchronously to the
450 *	  related functionality, it may need to access data structures of the
451 *	  related functionality which can be referenced using this pointer. The
452 *	  callback function can access the memory via the "data" field in the
453 *	  crypto_async_request data structure provided to the callback function.
454 *
455 * Setting the callback function that is triggered once the cipher operation
456 * completes
457 *
458 * The callback function is registered with the aead_request handle and
459 * must comply with the following template::
460 *
461 *	void callback_function(struct crypto_async_request *req, int error)
462 */
463static inline void aead_request_set_callback(struct aead_request *req,
464					     u32 flags,
465					     crypto_completion_t compl,
466					     void *data)
467{
468	req->base.complete = compl;
469	req->base.data = data;
470	req->base.flags = flags;
471}
472
473/**
474 * aead_request_set_crypt - set data buffers
475 * @req: request handle
476 * @src: source scatter / gather list
477 * @dst: destination scatter / gather list
478 * @cryptlen: number of bytes to process from @src
479 * @iv: IV for the cipher operation which must comply with the IV size defined
480 *      by crypto_aead_ivsize()
481 *
482 * Setting the source data and destination data scatter / gather lists which
483 * hold the associated data concatenated with the plaintext or ciphertext. See
484 * below for the authentication tag.
485 *
486 * For encryption, the source is treated as the plaintext and the
487 * destination is the ciphertext. For a decryption operation, the use is
488 * reversed - the source is the ciphertext and the destination is the plaintext.
489 *
490 * The memory structure for cipher operation has the following structure:
491 *
492 * - AEAD encryption input:  assoc data || plaintext
493 * - AEAD encryption output: assoc data || ciphertext || auth tag
494 * - AEAD decryption input:  assoc data || ciphertext || auth tag
495 * - AEAD decryption output: assoc data || plaintext
496 *
497 * Albeit the kernel requires the presence of the AAD buffer, however,
498 * the kernel does not fill the AAD buffer in the output case. If the
499 * caller wants to have that data buffer filled, the caller must either
500 * use an in-place cipher operation (i.e. same memory location for
501 * input/output memory location).
502 */
503static inline void aead_request_set_crypt(struct aead_request *req,
504					  struct scatterlist *src,
505					  struct scatterlist *dst,
506					  unsigned int cryptlen, u8 *iv)
507{
508	req->src = src;
509	req->dst = dst;
510	req->cryptlen = cryptlen;
511	req->iv = iv;
512}
513
514/**
515 * aead_request_set_ad - set associated data information
516 * @req: request handle
517 * @assoclen: number of bytes in associated data
518 *
519 * Setting the AD information.  This function sets the length of
520 * the associated data.
521 */
522static inline void aead_request_set_ad(struct aead_request *req,
523				       unsigned int assoclen)
524{
525	req->assoclen = assoclen;
526}
527
528#endif	/* _CRYPTO_AEAD_H */

 
  1/*
  2 * AEAD: Authenticated Encryption with Associated Data
  3 * 
  4 * Copyright (c) 2007-2015 Herbert Xu <herbert@gondor.apana.org.au>
  5 *
  6 * This program is free software; you can redistribute it and/or modify it
  7 * under the terms of the GNU General Public License as published by the Free
  8 * Software Foundation; either version 2 of the License, or (at your option) 
  9 * any later version.
 10 *
 11 */
 12
 13#ifndef _CRYPTO_AEAD_H
 14#define _CRYPTO_AEAD_H
 15
 16#include <linux/crypto.h>
 17#include <linux/kernel.h>
 18#include <linux/slab.h>
 19
 20/**
 21 * DOC: Authenticated Encryption With Associated Data (AEAD) Cipher API
 22 *
 23 * The AEAD cipher API is used with the ciphers of type CRYPTO_ALG_TYPE_AEAD
 24 * (listed as type "aead" in /proc/crypto)
 25 *
 26 * The most prominent examples for this type of encryption is GCM and CCM.
 27 * However, the kernel supports other types of AEAD ciphers which are defined
 28 * with the following cipher string:
 29 *
 30 *	authenc(keyed message digest, block cipher)
 31 *
 32 * For example: authenc(hmac(sha256), cbc(aes))
 33 *
 34 * The example code provided for the symmetric key cipher operation
 35 * applies here as well. Naturally all *skcipher* symbols must be exchanged
 36 * the *aead* pendants discussed in the following. In addition, for the AEAD
 37 * operation, the aead_request_set_ad function must be used to set the
 38 * pointer to the associated data memory location before performing the
 39 * encryption or decryption operation. In case of an encryption, the associated
 40 * data memory is filled during the encryption operation. For decryption, the
 41 * associated data memory must contain data that is used to verify the integrity
 42 * of the decrypted data. Another deviation from the asynchronous block cipher
 43 * operation is that the caller should explicitly check for -EBADMSG of the
 44 * crypto_aead_decrypt. That error indicates an authentication error, i.e.
 45 * a breach in the integrity of the message. In essence, that -EBADMSG error
 46 * code is the key bonus an AEAD cipher has over "standard" block chaining
 47 * modes.
 48 *
 49 * Memory Structure:
 50 *
 51 * To support the needs of the most prominent user of AEAD ciphers, namely
 52 * IPSEC, the AEAD ciphers have a special memory layout the caller must adhere
 53 * to.
 54 *
 55 * The scatter list pointing to the input data must contain:
 56 *
 57 * * for RFC4106 ciphers, the concatenation of
 58 *   associated authentication data || IV || plaintext or ciphertext. Note, the
 59 *   same IV (buffer) is also set with the aead_request_set_crypt call. Note,
 60 *   the API call of aead_request_set_ad must provide the length of the AAD and
 61 *   the IV. The API call of aead_request_set_crypt only points to the size of
 62 *   the input plaintext or ciphertext.
 63 *
 64 * * for "normal" AEAD ciphers, the concatenation of
 65 *   associated authentication data || plaintext or ciphertext.
 66 *
 67 * It is important to note that if multiple scatter gather list entries form
 68 * the input data mentioned above, the first entry must not point to a NULL
 69 * buffer. If there is any potential where the AAD buffer can be NULL, the
 70 * calling code must contain a precaution to ensure that this does not result
 71 * in the first scatter gather list entry pointing to a NULL buffer.
 
 
 
 
 
 
 72 */
 73
 74struct crypto_aead;
 75
 76/**
 77 *	struct aead_request - AEAD request
 78 *	@base: Common attributes for async crypto requests
 79 *	@assoclen: Length in bytes of associated data for authentication
 80 *	@cryptlen: Length of data to be encrypted or decrypted
 81 *	@iv: Initialisation vector
 82 *	@src: Source data
 83 *	@dst: Destination data
 84 *	@__ctx: Start of private context data
 85 */
 86struct aead_request {
 87	struct crypto_async_request base;
 88
 89	unsigned int assoclen;
 90	unsigned int cryptlen;
 91
 92	u8 *iv;
 93
 94	struct scatterlist *src;
 95	struct scatterlist *dst;
 96
 97	void *__ctx[] CRYPTO_MINALIGN_ATTR;
 98};
 99
100/**
101 * struct aead_alg - AEAD cipher definition
102 * @maxauthsize: Set the maximum authentication tag size supported by the
103 *		 transformation. A transformation may support smaller tag sizes.
104 *		 As the authentication tag is a message digest to ensure the
105 *		 integrity of the encrypted data, a consumer typically wants the
106 *		 largest authentication tag possible as defined by this
107 *		 variable.
108 * @setauthsize: Set authentication size for the AEAD transformation. This
109 *		 function is used to specify the consumer requested size of the
110 * 		 authentication tag to be either generated by the transformation
111 *		 during encryption or the size of the authentication tag to be
112 *		 supplied during the decryption operation. This function is also
113 *		 responsible for checking the authentication tag size for
114 *		 validity.
115 * @setkey: see struct skcipher_alg
116 * @encrypt: see struct skcipher_alg
117 * @decrypt: see struct skcipher_alg
118 * @geniv: see struct skcipher_alg
119 * @ivsize: see struct skcipher_alg
120 * @chunksize: see struct skcipher_alg
121 * @init: Initialize the cryptographic transformation object. This function
122 *	  is used to initialize the cryptographic transformation object.
123 *	  This function is called only once at the instantiation time, right
124 *	  after the transformation context was allocated. In case the
125 *	  cryptographic hardware has some special requirements which need to
126 *	  be handled by software, this function shall check for the precise
127 *	  requirement of the transformation and put any software fallbacks
128 *	  in place.
129 * @exit: Deinitialize the cryptographic transformation object. This is a
130 *	  counterpart to @init, used to remove various changes set in
131 *	  @init.
132 * @base: Definition of a generic crypto cipher algorithm.
133 *
134 * All fields except @ivsize is mandatory and must be filled.
135 */
136struct aead_alg {
137	int (*setkey)(struct crypto_aead *tfm, const u8 *key,
138	              unsigned int keylen);
139	int (*setauthsize)(struct crypto_aead *tfm, unsigned int authsize);
140	int (*encrypt)(struct aead_request *req);
141	int (*decrypt)(struct aead_request *req);
142	int (*init)(struct crypto_aead *tfm);
143	void (*exit)(struct crypto_aead *tfm);
144
145	const char *geniv;
146
147	unsigned int ivsize;
148	unsigned int maxauthsize;
149	unsigned int chunksize;
150
151	struct crypto_alg base;
152};
153
154struct crypto_aead {
155	unsigned int authsize;
156	unsigned int reqsize;
157
158	struct crypto_tfm base;
159};
160
161static inline struct crypto_aead *__crypto_aead_cast(struct crypto_tfm *tfm)
162{
163	return container_of(tfm, struct crypto_aead, base);
164}
165
166/**
167 * crypto_alloc_aead() - allocate AEAD cipher handle
168 * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
169 *	     AEAD cipher
170 * @type: specifies the type of the cipher
171 * @mask: specifies the mask for the cipher
172 *
173 * Allocate a cipher handle for an AEAD. The returned struct
174 * crypto_aead is the cipher handle that is required for any subsequent
175 * API invocation for that AEAD.
176 *
177 * Return: allocated cipher handle in case of success; IS_ERR() is true in case
178 *	   of an error, PTR_ERR() returns the error code.
179 */
180struct crypto_aead *crypto_alloc_aead(const char *alg_name, u32 type, u32 mask);
181
182static inline struct crypto_tfm *crypto_aead_tfm(struct crypto_aead *tfm)
183{
184	return &tfm->base;
185}
186
187/**
188 * crypto_free_aead() - zeroize and free aead handle
189 * @tfm: cipher handle to be freed
 
 
190 */
191static inline void crypto_free_aead(struct crypto_aead *tfm)
192{
193	crypto_destroy_tfm(tfm, crypto_aead_tfm(tfm));
194}
195
 
 
 
 
 
196static inline struct aead_alg *crypto_aead_alg(struct crypto_aead *tfm)
197{
198	return container_of(crypto_aead_tfm(tfm)->__crt_alg,
199			    struct aead_alg, base);
200}
201
202static inline unsigned int crypto_aead_alg_ivsize(struct aead_alg *alg)
203{
204	return alg->ivsize;
205}
206
207/**
208 * crypto_aead_ivsize() - obtain IV size
209 * @tfm: cipher handle
210 *
211 * The size of the IV for the aead referenced by the cipher handle is
212 * returned. This IV size may be zero if the cipher does not need an IV.
213 *
214 * Return: IV size in bytes
215 */
216static inline unsigned int crypto_aead_ivsize(struct crypto_aead *tfm)
217{
218	return crypto_aead_alg_ivsize(crypto_aead_alg(tfm));
219}
220
221/**
222 * crypto_aead_authsize() - obtain maximum authentication data size
223 * @tfm: cipher handle
224 *
225 * The maximum size of the authentication data for the AEAD cipher referenced
226 * by the AEAD cipher handle is returned. The authentication data size may be
227 * zero if the cipher implements a hard-coded maximum.
228 *
229 * The authentication data may also be known as "tag value".
230 *
231 * Return: authentication data size / tag size in bytes
232 */
233static inline unsigned int crypto_aead_authsize(struct crypto_aead *tfm)
234{
235	return tfm->authsize;
236}
237
 
 
 
 
 
 
 
 
 
 
238/**
239 * crypto_aead_blocksize() - obtain block size of cipher
240 * @tfm: cipher handle
241 *
242 * The block size for the AEAD referenced with the cipher handle is returned.
243 * The caller may use that information to allocate appropriate memory for the
244 * data returned by the encryption or decryption operation
245 *
246 * Return: block size of cipher
247 */
248static inline unsigned int crypto_aead_blocksize(struct crypto_aead *tfm)
249{
250	return crypto_tfm_alg_blocksize(crypto_aead_tfm(tfm));
251}
252
253static inline unsigned int crypto_aead_alignmask(struct crypto_aead *tfm)
254{
255	return crypto_tfm_alg_alignmask(crypto_aead_tfm(tfm));
256}
257
258static inline u32 crypto_aead_get_flags(struct crypto_aead *tfm)
259{
260	return crypto_tfm_get_flags(crypto_aead_tfm(tfm));
261}
262
263static inline void crypto_aead_set_flags(struct crypto_aead *tfm, u32 flags)
264{
265	crypto_tfm_set_flags(crypto_aead_tfm(tfm), flags);
266}
267
268static inline void crypto_aead_clear_flags(struct crypto_aead *tfm, u32 flags)
269{
270	crypto_tfm_clear_flags(crypto_aead_tfm(tfm), flags);
271}
272
273/**
274 * crypto_aead_setkey() - set key for cipher
275 * @tfm: cipher handle
276 * @key: buffer holding the key
277 * @keylen: length of the key in bytes
278 *
279 * The caller provided key is set for the AEAD referenced by the cipher
280 * handle.
281 *
282 * Note, the key length determines the cipher type. Many block ciphers implement
283 * different cipher modes depending on the key size, such as AES-128 vs AES-192
284 * vs. AES-256. When providing a 16 byte key for an AES cipher handle, AES-128
285 * is performed.
286 *
287 * Return: 0 if the setting of the key was successful; < 0 if an error occurred
288 */
289int crypto_aead_setkey(struct crypto_aead *tfm,
290		       const u8 *key, unsigned int keylen);
291
292/**
293 * crypto_aead_setauthsize() - set authentication data size
294 * @tfm: cipher handle
295 * @authsize: size of the authentication data / tag in bytes
296 *
297 * Set the authentication data size / tag size. AEAD requires an authentication
298 * tag (or MAC) in addition to the associated data.
299 *
300 * Return: 0 if the setting of the key was successful; < 0 if an error occurred
301 */
302int crypto_aead_setauthsize(struct crypto_aead *tfm, unsigned int authsize);
303
304static inline struct crypto_aead *crypto_aead_reqtfm(struct aead_request *req)
305{
306	return __crypto_aead_cast(req->base.tfm);
307}
308
309/**
310 * crypto_aead_encrypt() - encrypt plaintext
311 * @req: reference to the aead_request handle that holds all information
312 *	 needed to perform the cipher operation
313 *
314 * Encrypt plaintext data using the aead_request handle. That data structure
315 * and how it is filled with data is discussed with the aead_request_*
316 * functions.
317 *
318 * IMPORTANT NOTE The encryption operation creates the authentication data /
319 *		  tag. That data is concatenated with the created ciphertext.
320 *		  The ciphertext memory size is therefore the given number of
321 *		  block cipher blocks + the size defined by the
322 *		  crypto_aead_setauthsize invocation. The caller must ensure
323 *		  that sufficient memory is available for the ciphertext and
324 *		  the authentication tag.
325 *
326 * Return: 0 if the cipher operation was successful; < 0 if an error occurred
327 */
328static inline int crypto_aead_encrypt(struct aead_request *req)
329{
330	struct crypto_aead *aead = crypto_aead_reqtfm(req);
331
332	if (crypto_aead_get_flags(aead) & CRYPTO_TFM_NEED_KEY)
333		return -ENOKEY;
334
335	return crypto_aead_alg(aead)->encrypt(req);
336}
337
338/**
339 * crypto_aead_decrypt() - decrypt ciphertext
340 * @req: reference to the ablkcipher_request handle that holds all information
341 *	 needed to perform the cipher operation
342 *
343 * Decrypt ciphertext data using the aead_request handle. That data structure
344 * and how it is filled with data is discussed with the aead_request_*
345 * functions.
346 *
347 * IMPORTANT NOTE The caller must concatenate the ciphertext followed by the
348 *		  authentication data / tag. That authentication data / tag
349 *		  must have the size defined by the crypto_aead_setauthsize
350 *		  invocation.
351 *
352 *
353 * Return: 0 if the cipher operation was successful; -EBADMSG: The AEAD
354 *	   cipher operation performs the authentication of the data during the
355 *	   decryption operation. Therefore, the function returns this error if
356 *	   the authentication of the ciphertext was unsuccessful (i.e. the
357 *	   integrity of the ciphertext or the associated data was violated);
358 *	   < 0 if an error occurred.
359 */
360static inline int crypto_aead_decrypt(struct aead_request *req)
361{
362	struct crypto_aead *aead = crypto_aead_reqtfm(req);
363
364	if (crypto_aead_get_flags(aead) & CRYPTO_TFM_NEED_KEY)
365		return -ENOKEY;
366
367	if (req->cryptlen < crypto_aead_authsize(aead))
368		return -EINVAL;
369
370	return crypto_aead_alg(aead)->decrypt(req);
371}
372
373/**
374 * DOC: Asynchronous AEAD Request Handle
375 *
376 * The aead_request data structure contains all pointers to data required for
377 * the AEAD cipher operation. This includes the cipher handle (which can be
378 * used by multiple aead_request instances), pointer to plaintext and
379 * ciphertext, asynchronous callback function, etc. It acts as a handle to the
380 * aead_request_* API calls in a similar way as AEAD handle to the
381 * crypto_aead_* API calls.
382 */
383
384/**
385 * crypto_aead_reqsize() - obtain size of the request data structure
386 * @tfm: cipher handle
387 *
388 * Return: number of bytes
389 */
390static inline unsigned int crypto_aead_reqsize(struct crypto_aead *tfm)
391{
392	return tfm->reqsize;
393}
394
395/**
396 * aead_request_set_tfm() - update cipher handle reference in request
397 * @req: request handle to be modified
398 * @tfm: cipher handle that shall be added to the request handle
399 *
400 * Allow the caller to replace the existing aead handle in the request
401 * data structure with a different one.
402 */
403static inline void aead_request_set_tfm(struct aead_request *req,
404					struct crypto_aead *tfm)
405{
406	req->base.tfm = crypto_aead_tfm(tfm);
407}
408
409/**
410 * aead_request_alloc() - allocate request data structure
411 * @tfm: cipher handle to be registered with the request
412 * @gfp: memory allocation flag that is handed to kmalloc by the API call.
413 *
414 * Allocate the request data structure that must be used with the AEAD
415 * encrypt and decrypt API calls. During the allocation, the provided aead
416 * handle is registered in the request data structure.
417 *
418 * Return: allocated request handle in case of success, or NULL if out of memory
419 */
420static inline struct aead_request *aead_request_alloc(struct crypto_aead *tfm,
421						      gfp_t gfp)
422{
423	struct aead_request *req;
424
425	req = kmalloc(sizeof(*req) + crypto_aead_reqsize(tfm), gfp);
426
427	if (likely(req))
428		aead_request_set_tfm(req, tfm);
429
430	return req;
431}
432
433/**
434 * aead_request_free() - zeroize and free request data structure
435 * @req: request data structure cipher handle to be freed
436 */
437static inline void aead_request_free(struct aead_request *req)
438{
439	kzfree(req);
440}
441
442/**
443 * aead_request_set_callback() - set asynchronous callback function
444 * @req: request handle
445 * @flags: specify zero or an ORing of the flags
446 *	   CRYPTO_TFM_REQ_MAY_BACKLOG the request queue may back log and
447 *	   increase the wait queue beyond the initial maximum size;
448 *	   CRYPTO_TFM_REQ_MAY_SLEEP the request processing may sleep
449 * @compl: callback function pointer to be registered with the request handle
450 * @data: The data pointer refers to memory that is not used by the kernel
451 *	  crypto API, but provided to the callback function for it to use. Here,
452 *	  the caller can provide a reference to memory the callback function can
453 *	  operate on. As the callback function is invoked asynchronously to the
454 *	  related functionality, it may need to access data structures of the
455 *	  related functionality which can be referenced using this pointer. The
456 *	  callback function can access the memory via the "data" field in the
457 *	  crypto_async_request data structure provided to the callback function.
458 *
459 * Setting the callback function that is triggered once the cipher operation
460 * completes
461 *
462 * The callback function is registered with the aead_request handle and
463 * must comply with the following template::
464 *
465 *	void callback_function(struct crypto_async_request *req, int error)
466 */
467static inline void aead_request_set_callback(struct aead_request *req,
468					     u32 flags,
469					     crypto_completion_t compl,
470					     void *data)
471{
472	req->base.complete = compl;
473	req->base.data = data;
474	req->base.flags = flags;
475}
476
477/**
478 * aead_request_set_crypt - set data buffers
479 * @req: request handle
480 * @src: source scatter / gather list
481 * @dst: destination scatter / gather list
482 * @cryptlen: number of bytes to process from @src
483 * @iv: IV for the cipher operation which must comply with the IV size defined
484 *      by crypto_aead_ivsize()
485 *
486 * Setting the source data and destination data scatter / gather lists which
487 * hold the associated data concatenated with the plaintext or ciphertext. See
488 * below for the authentication tag.
489 *
490 * For encryption, the source is treated as the plaintext and the
491 * destination is the ciphertext. For a decryption operation, the use is
492 * reversed - the source is the ciphertext and the destination is the plaintext.
493 *
494 * The memory structure for cipher operation has the following structure:
495 *
496 * - AEAD encryption input:  assoc data || plaintext
497 * - AEAD encryption output: assoc data || cipherntext || auth tag
498 * - AEAD decryption input:  assoc data || ciphertext || auth tag
499 * - AEAD decryption output: assoc data || plaintext
500 *
501 * Albeit the kernel requires the presence of the AAD buffer, however,
502 * the kernel does not fill the AAD buffer in the output case. If the
503 * caller wants to have that data buffer filled, the caller must either
504 * use an in-place cipher operation (i.e. same memory location for
505 * input/output memory location).
506 */
507static inline void aead_request_set_crypt(struct aead_request *req,
508					  struct scatterlist *src,
509					  struct scatterlist *dst,
510					  unsigned int cryptlen, u8 *iv)
511{
512	req->src = src;
513	req->dst = dst;
514	req->cryptlen = cryptlen;
515	req->iv = iv;
516}
517
518/**
519 * aead_request_set_ad - set associated data information
520 * @req: request handle
521 * @assoclen: number of bytes in associated data
522 *
523 * Setting the AD information.  This function sets the length of
524 * the associated data.
525 */
526static inline void aead_request_set_ad(struct aead_request *req,
527				       unsigned int assoclen)
528{
529	req->assoclen = assoclen;
530}
531
532#endif	/* _CRYPTO_AEAD_H */