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1/*
2 * AEAD: Authenticated Encryption with Associated Data
3 *
4 * Copyright (c) 2007 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 * struct aead_givcrypt_request - AEAD request with IV generation
22 * @seq: Sequence number for IV generation
23 * @giv: Space for generated IV
24 * @areq: The AEAD request itself
25 */
26struct aead_givcrypt_request {
27 u64 seq;
28 u8 *giv;
29
30 struct aead_request areq;
31};
32
33static inline struct crypto_aead *aead_givcrypt_reqtfm(
34 struct aead_givcrypt_request *req)
35{
36 return crypto_aead_reqtfm(&req->areq);
37}
38
39static inline int crypto_aead_givencrypt(struct aead_givcrypt_request *req)
40{
41 struct aead_tfm *crt = crypto_aead_crt(aead_givcrypt_reqtfm(req));
42 return crt->givencrypt(req);
43};
44
45static inline int crypto_aead_givdecrypt(struct aead_givcrypt_request *req)
46{
47 struct aead_tfm *crt = crypto_aead_crt(aead_givcrypt_reqtfm(req));
48 return crt->givdecrypt(req);
49};
50
51static inline void aead_givcrypt_set_tfm(struct aead_givcrypt_request *req,
52 struct crypto_aead *tfm)
53{
54 req->areq.base.tfm = crypto_aead_tfm(tfm);
55}
56
57static inline struct aead_givcrypt_request *aead_givcrypt_alloc(
58 struct crypto_aead *tfm, gfp_t gfp)
59{
60 struct aead_givcrypt_request *req;
61
62 req = kmalloc(sizeof(struct aead_givcrypt_request) +
63 crypto_aead_reqsize(tfm), gfp);
64
65 if (likely(req))
66 aead_givcrypt_set_tfm(req, tfm);
67
68 return req;
69}
70
71static inline void aead_givcrypt_free(struct aead_givcrypt_request *req)
72{
73 kfree(req);
74}
75
76static inline void aead_givcrypt_set_callback(
77 struct aead_givcrypt_request *req, u32 flags,
78 crypto_completion_t complete, void *data)
79{
80 aead_request_set_callback(&req->areq, flags, complete, data);
81}
82
83static inline void aead_givcrypt_set_crypt(struct aead_givcrypt_request *req,
84 struct scatterlist *src,
85 struct scatterlist *dst,
86 unsigned int nbytes, void *iv)
87{
88 aead_request_set_crypt(&req->areq, src, dst, nbytes, iv);
89}
90
91static inline void aead_givcrypt_set_assoc(struct aead_givcrypt_request *req,
92 struct scatterlist *assoc,
93 unsigned int assoclen)
94{
95 aead_request_set_assoc(&req->areq, assoc, assoclen);
96}
97
98static inline void aead_givcrypt_set_giv(struct aead_givcrypt_request *req,
99 u8 *giv, u64 seq)
100{
101 req->giv = giv;
102 req->seq = seq;
103}
104
105#endif /* _CRYPTO_AEAD_H */
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 */
189static inline void crypto_free_aead(struct crypto_aead *tfm)
190{
191 crypto_destroy_tfm(tfm, crypto_aead_tfm(tfm));
192}
193
194static inline struct aead_alg *crypto_aead_alg(struct crypto_aead *tfm)
195{
196 return container_of(crypto_aead_tfm(tfm)->__crt_alg,
197 struct aead_alg, base);
198}
199
200static inline unsigned int crypto_aead_alg_ivsize(struct aead_alg *alg)
201{
202 return alg->ivsize;
203}
204
205/**
206 * crypto_aead_ivsize() - obtain IV size
207 * @tfm: cipher handle
208 *
209 * The size of the IV for the aead referenced by the cipher handle is
210 * returned. This IV size may be zero if the cipher does not need an IV.
211 *
212 * Return: IV size in bytes
213 */
214static inline unsigned int crypto_aead_ivsize(struct crypto_aead *tfm)
215{
216 return crypto_aead_alg_ivsize(crypto_aead_alg(tfm));
217}
218
219/**
220 * crypto_aead_authsize() - obtain maximum authentication data size
221 * @tfm: cipher handle
222 *
223 * The maximum size of the authentication data for the AEAD cipher referenced
224 * by the AEAD cipher handle is returned. The authentication data size may be
225 * zero if the cipher implements a hard-coded maximum.
226 *
227 * The authentication data may also be known as "tag value".
228 *
229 * Return: authentication data size / tag size in bytes
230 */
231static inline unsigned int crypto_aead_authsize(struct crypto_aead *tfm)
232{
233 return tfm->authsize;
234}
235
236static inline unsigned int crypto_aead_alg_maxauthsize(struct aead_alg *alg)
237{
238 return alg->maxauthsize;
239}
240
241static inline unsigned int crypto_aead_maxauthsize(struct crypto_aead *aead)
242{
243 return crypto_aead_alg_maxauthsize(crypto_aead_alg(aead));
244}
245
246/**
247 * crypto_aead_blocksize() - obtain block size of cipher
248 * @tfm: cipher handle
249 *
250 * The block size for the AEAD referenced with the cipher handle is returned.
251 * The caller may use that information to allocate appropriate memory for the
252 * data returned by the encryption or decryption operation
253 *
254 * Return: block size of cipher
255 */
256static inline unsigned int crypto_aead_blocksize(struct crypto_aead *tfm)
257{
258 return crypto_tfm_alg_blocksize(crypto_aead_tfm(tfm));
259}
260
261static inline unsigned int crypto_aead_alignmask(struct crypto_aead *tfm)
262{
263 return crypto_tfm_alg_alignmask(crypto_aead_tfm(tfm));
264}
265
266static inline u32 crypto_aead_get_flags(struct crypto_aead *tfm)
267{
268 return crypto_tfm_get_flags(crypto_aead_tfm(tfm));
269}
270
271static inline void crypto_aead_set_flags(struct crypto_aead *tfm, u32 flags)
272{
273 crypto_tfm_set_flags(crypto_aead_tfm(tfm), flags);
274}
275
276static inline void crypto_aead_clear_flags(struct crypto_aead *tfm, u32 flags)
277{
278 crypto_tfm_clear_flags(crypto_aead_tfm(tfm), flags);
279}
280
281/**
282 * crypto_aead_setkey() - set key for cipher
283 * @tfm: cipher handle
284 * @key: buffer holding the key
285 * @keylen: length of the key in bytes
286 *
287 * The caller provided key is set for the AEAD referenced by the cipher
288 * handle.
289 *
290 * Note, the key length determines the cipher type. Many block ciphers implement
291 * different cipher modes depending on the key size, such as AES-128 vs AES-192
292 * vs. AES-256. When providing a 16 byte key for an AES cipher handle, AES-128
293 * is performed.
294 *
295 * Return: 0 if the setting of the key was successful; < 0 if an error occurred
296 */
297int crypto_aead_setkey(struct crypto_aead *tfm,
298 const u8 *key, unsigned int keylen);
299
300/**
301 * crypto_aead_setauthsize() - set authentication data size
302 * @tfm: cipher handle
303 * @authsize: size of the authentication data / tag in bytes
304 *
305 * Set the authentication data size / tag size. AEAD requires an authentication
306 * tag (or MAC) in addition to the associated data.
307 *
308 * Return: 0 if the setting of the key was successful; < 0 if an error occurred
309 */
310int crypto_aead_setauthsize(struct crypto_aead *tfm, unsigned int authsize);
311
312static inline struct crypto_aead *crypto_aead_reqtfm(struct aead_request *req)
313{
314 return __crypto_aead_cast(req->base.tfm);
315}
316
317/**
318 * crypto_aead_encrypt() - encrypt plaintext
319 * @req: reference to the aead_request handle that holds all information
320 * needed to perform the cipher operation
321 *
322 * Encrypt plaintext data using the aead_request handle. That data structure
323 * and how it is filled with data is discussed with the aead_request_*
324 * functions.
325 *
326 * IMPORTANT NOTE The encryption operation creates the authentication data /
327 * tag. That data is concatenated with the created ciphertext.
328 * The ciphertext memory size is therefore the given number of
329 * block cipher blocks + the size defined by the
330 * crypto_aead_setauthsize invocation. The caller must ensure
331 * that sufficient memory is available for the ciphertext and
332 * the authentication tag.
333 *
334 * Return: 0 if the cipher operation was successful; < 0 if an error occurred
335 */
336int crypto_aead_encrypt(struct aead_request *req);
337
338/**
339 * crypto_aead_decrypt() - decrypt ciphertext
340 * @req: reference to the aead_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 */
360int crypto_aead_decrypt(struct aead_request *req);
361
362/**
363 * DOC: Asynchronous AEAD Request Handle
364 *
365 * The aead_request data structure contains all pointers to data required for
366 * the AEAD cipher operation. This includes the cipher handle (which can be
367 * used by multiple aead_request instances), pointer to plaintext and
368 * ciphertext, asynchronous callback function, etc. It acts as a handle to the
369 * aead_request_* API calls in a similar way as AEAD handle to the
370 * crypto_aead_* API calls.
371 */
372
373/**
374 * crypto_aead_reqsize() - obtain size of the request data structure
375 * @tfm: cipher handle
376 *
377 * Return: number of bytes
378 */
379static inline unsigned int crypto_aead_reqsize(struct crypto_aead *tfm)
380{
381 return tfm->reqsize;
382}
383
384/**
385 * aead_request_set_tfm() - update cipher handle reference in request
386 * @req: request handle to be modified
387 * @tfm: cipher handle that shall be added to the request handle
388 *
389 * Allow the caller to replace the existing aead handle in the request
390 * data structure with a different one.
391 */
392static inline void aead_request_set_tfm(struct aead_request *req,
393 struct crypto_aead *tfm)
394{
395 req->base.tfm = crypto_aead_tfm(tfm);
396}
397
398/**
399 * aead_request_alloc() - allocate request data structure
400 * @tfm: cipher handle to be registered with the request
401 * @gfp: memory allocation flag that is handed to kmalloc by the API call.
402 *
403 * Allocate the request data structure that must be used with the AEAD
404 * encrypt and decrypt API calls. During the allocation, the provided aead
405 * handle is registered in the request data structure.
406 *
407 * Return: allocated request handle in case of success, or NULL if out of memory
408 */
409static inline struct aead_request *aead_request_alloc(struct crypto_aead *tfm,
410 gfp_t gfp)
411{
412 struct aead_request *req;
413
414 req = kmalloc(sizeof(*req) + crypto_aead_reqsize(tfm), gfp);
415
416 if (likely(req))
417 aead_request_set_tfm(req, tfm);
418
419 return req;
420}
421
422/**
423 * aead_request_free() - zeroize and free request data structure
424 * @req: request data structure cipher handle to be freed
425 */
426static inline void aead_request_free(struct aead_request *req)
427{
428 kfree_sensitive(req);
429}
430
431/**
432 * aead_request_set_callback() - set asynchronous callback function
433 * @req: request handle
434 * @flags: specify zero or an ORing of the flags
435 * CRYPTO_TFM_REQ_MAY_BACKLOG the request queue may back log and
436 * increase the wait queue beyond the initial maximum size;
437 * CRYPTO_TFM_REQ_MAY_SLEEP the request processing may sleep
438 * @compl: callback function pointer to be registered with the request handle
439 * @data: The data pointer refers to memory that is not used by the kernel
440 * crypto API, but provided to the callback function for it to use. Here,
441 * the caller can provide a reference to memory the callback function can
442 * operate on. As the callback function is invoked asynchronously to the
443 * related functionality, it may need to access data structures of the
444 * related functionality which can be referenced using this pointer. The
445 * callback function can access the memory via the "data" field in the
446 * crypto_async_request data structure provided to the callback function.
447 *
448 * Setting the callback function that is triggered once the cipher operation
449 * completes
450 *
451 * The callback function is registered with the aead_request handle and
452 * must comply with the following template::
453 *
454 * void callback_function(struct crypto_async_request *req, int error)
455 */
456static inline void aead_request_set_callback(struct aead_request *req,
457 u32 flags,
458 crypto_completion_t compl,
459 void *data)
460{
461 req->base.complete = compl;
462 req->base.data = data;
463 req->base.flags = flags;
464}
465
466/**
467 * aead_request_set_crypt - set data buffers
468 * @req: request handle
469 * @src: source scatter / gather list
470 * @dst: destination scatter / gather list
471 * @cryptlen: number of bytes to process from @src
472 * @iv: IV for the cipher operation which must comply with the IV size defined
473 * by crypto_aead_ivsize()
474 *
475 * Setting the source data and destination data scatter / gather lists which
476 * hold the associated data concatenated with the plaintext or ciphertext. See
477 * below for the authentication tag.
478 *
479 * For encryption, the source is treated as the plaintext and the
480 * destination is the ciphertext. For a decryption operation, the use is
481 * reversed - the source is the ciphertext and the destination is the plaintext.
482 *
483 * The memory structure for cipher operation has the following structure:
484 *
485 * - AEAD encryption input: assoc data || plaintext
486 * - AEAD encryption output: assoc data || cipherntext || auth tag
487 * - AEAD decryption input: assoc data || ciphertext || auth tag
488 * - AEAD decryption output: assoc data || plaintext
489 *
490 * Albeit the kernel requires the presence of the AAD buffer, however,
491 * the kernel does not fill the AAD buffer in the output case. If the
492 * caller wants to have that data buffer filled, the caller must either
493 * use an in-place cipher operation (i.e. same memory location for
494 * input/output memory location).
495 */
496static inline void aead_request_set_crypt(struct aead_request *req,
497 struct scatterlist *src,
498 struct scatterlist *dst,
499 unsigned int cryptlen, u8 *iv)
500{
501 req->src = src;
502 req->dst = dst;
503 req->cryptlen = cryptlen;
504 req->iv = iv;
505}
506
507/**
508 * aead_request_set_ad - set associated data information
509 * @req: request handle
510 * @assoclen: number of bytes in associated data
511 *
512 * Setting the AD information. This function sets the length of
513 * the associated data.
514 */
515static inline void aead_request_set_ad(struct aead_request *req,
516 unsigned int assoclen)
517{
518 req->assoclen = assoclen;
519}
520
521#endif /* _CRYPTO_AEAD_H */