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743edf57 HX |
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> | |
3a282bd2 | 18 | #include <linux/slab.h> |
743edf57 | 19 | |
5d1d65f8 HX |
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 asynchronous block cipher operation | |
35 | * applies here as well. Naturally all *ablkcipher* symbols must be exchanged | |
36 | * the *aead* pendants discussed in the following. In addtion, for the AEAD | |
37 | * operation, the aead_request_set_assoc 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 | ||
50 | /** | |
51 | * struct aead_request - AEAD request | |
52 | * @base: Common attributes for async crypto requests | |
53 | * @assoclen: Length in bytes of associated data for authentication | |
54 | * @cryptlen: Length of data to be encrypted or decrypted | |
55 | * @iv: Initialisation vector | |
56 | * @assoc: Associated data | |
57 | * @src: Source data | |
58 | * @dst: Destination data | |
59 | * @__ctx: Start of private context data | |
60 | */ | |
61 | struct aead_request { | |
62 | struct crypto_async_request base; | |
63 | ||
64 | unsigned int assoclen; | |
65 | unsigned int cryptlen; | |
66 | ||
67 | u8 *iv; | |
68 | ||
69 | struct scatterlist *assoc; | |
70 | struct scatterlist *src; | |
71 | struct scatterlist *dst; | |
72 | ||
73 | void *__ctx[] CRYPTO_MINALIGN_ATTR; | |
74 | }; | |
75 | ||
743edf57 HX |
76 | /** |
77 | * struct aead_givcrypt_request - AEAD request with IV generation | |
78 | * @seq: Sequence number for IV generation | |
79 | * @giv: Space for generated IV | |
80 | * @areq: The AEAD request itself | |
81 | */ | |
82 | struct aead_givcrypt_request { | |
83 | u64 seq; | |
84 | u8 *giv; | |
85 | ||
86 | struct aead_request areq; | |
87 | }; | |
88 | ||
5d1d65f8 HX |
89 | struct crypto_aead { |
90 | int (*encrypt)(struct aead_request *req); | |
91 | int (*decrypt)(struct aead_request *req); | |
92 | int (*givencrypt)(struct aead_givcrypt_request *req); | |
93 | int (*givdecrypt)(struct aead_givcrypt_request *req); | |
94 | ||
95 | struct crypto_aead *child; | |
96 | ||
97 | unsigned int ivsize; | |
98 | unsigned int authsize; | |
99 | unsigned int reqsize; | |
100 | ||
101 | struct crypto_tfm base; | |
102 | }; | |
103 | ||
104 | static inline struct crypto_aead *__crypto_aead_cast(struct crypto_tfm *tfm) | |
105 | { | |
106 | return container_of(tfm, struct crypto_aead, base); | |
107 | } | |
108 | ||
109 | /** | |
110 | * crypto_alloc_aead() - allocate AEAD cipher handle | |
111 | * @alg_name: is the cra_name / name or cra_driver_name / driver name of the | |
112 | * AEAD cipher | |
113 | * @type: specifies the type of the cipher | |
114 | * @mask: specifies the mask for the cipher | |
115 | * | |
116 | * Allocate a cipher handle for an AEAD. The returned struct | |
117 | * crypto_aead is the cipher handle that is required for any subsequent | |
118 | * API invocation for that AEAD. | |
119 | * | |
120 | * Return: allocated cipher handle in case of success; IS_ERR() is true in case | |
121 | * of an error, PTR_ERR() returns the error code. | |
122 | */ | |
123 | struct crypto_aead *crypto_alloc_aead(const char *alg_name, u32 type, u32 mask); | |
124 | ||
125 | static inline struct crypto_tfm *crypto_aead_tfm(struct crypto_aead *tfm) | |
126 | { | |
127 | return &tfm->base; | |
128 | } | |
129 | ||
130 | /** | |
131 | * crypto_free_aead() - zeroize and free aead handle | |
132 | * @tfm: cipher handle to be freed | |
133 | */ | |
134 | static inline void crypto_free_aead(struct crypto_aead *tfm) | |
135 | { | |
136 | crypto_destroy_tfm(tfm, crypto_aead_tfm(tfm)); | |
137 | } | |
138 | ||
139 | static inline struct crypto_aead *crypto_aead_crt(struct crypto_aead *tfm) | |
140 | { | |
141 | return tfm; | |
142 | } | |
143 | ||
144 | /** | |
145 | * crypto_aead_ivsize() - obtain IV size | |
146 | * @tfm: cipher handle | |
147 | * | |
148 | * The size of the IV for the aead referenced by the cipher handle is | |
149 | * returned. This IV size may be zero if the cipher does not need an IV. | |
150 | * | |
151 | * Return: IV size in bytes | |
152 | */ | |
153 | static inline unsigned int crypto_aead_ivsize(struct crypto_aead *tfm) | |
154 | { | |
155 | return tfm->ivsize; | |
156 | } | |
157 | ||
158 | /** | |
159 | * crypto_aead_authsize() - obtain maximum authentication data size | |
160 | * @tfm: cipher handle | |
161 | * | |
162 | * The maximum size of the authentication data for the AEAD cipher referenced | |
163 | * by the AEAD cipher handle is returned. The authentication data size may be | |
164 | * zero if the cipher implements a hard-coded maximum. | |
165 | * | |
166 | * The authentication data may also be known as "tag value". | |
167 | * | |
168 | * Return: authentication data size / tag size in bytes | |
169 | */ | |
170 | static inline unsigned int crypto_aead_authsize(struct crypto_aead *tfm) | |
171 | { | |
172 | return tfm->authsize; | |
173 | } | |
174 | ||
175 | /** | |
176 | * crypto_aead_blocksize() - obtain block size of cipher | |
177 | * @tfm: cipher handle | |
178 | * | |
179 | * The block size for the AEAD referenced with the cipher handle is returned. | |
180 | * The caller may use that information to allocate appropriate memory for the | |
181 | * data returned by the encryption or decryption operation | |
182 | * | |
183 | * Return: block size of cipher | |
184 | */ | |
185 | static inline unsigned int crypto_aead_blocksize(struct crypto_aead *tfm) | |
186 | { | |
187 | return crypto_tfm_alg_blocksize(crypto_aead_tfm(tfm)); | |
188 | } | |
189 | ||
190 | static inline unsigned int crypto_aead_alignmask(struct crypto_aead *tfm) | |
191 | { | |
192 | return crypto_tfm_alg_alignmask(crypto_aead_tfm(tfm)); | |
193 | } | |
194 | ||
195 | static inline u32 crypto_aead_get_flags(struct crypto_aead *tfm) | |
196 | { | |
197 | return crypto_tfm_get_flags(crypto_aead_tfm(tfm)); | |
198 | } | |
199 | ||
200 | static inline void crypto_aead_set_flags(struct crypto_aead *tfm, u32 flags) | |
201 | { | |
202 | crypto_tfm_set_flags(crypto_aead_tfm(tfm), flags); | |
203 | } | |
204 | ||
205 | static inline void crypto_aead_clear_flags(struct crypto_aead *tfm, u32 flags) | |
206 | { | |
207 | crypto_tfm_clear_flags(crypto_aead_tfm(tfm), flags); | |
208 | } | |
209 | ||
210 | /** | |
211 | * crypto_aead_setkey() - set key for cipher | |
212 | * @tfm: cipher handle | |
213 | * @key: buffer holding the key | |
214 | * @keylen: length of the key in bytes | |
215 | * | |
216 | * The caller provided key is set for the AEAD referenced by the cipher | |
217 | * handle. | |
218 | * | |
219 | * Note, the key length determines the cipher type. Many block ciphers implement | |
220 | * different cipher modes depending on the key size, such as AES-128 vs AES-192 | |
221 | * vs. AES-256. When providing a 16 byte key for an AES cipher handle, AES-128 | |
222 | * is performed. | |
223 | * | |
224 | * Return: 0 if the setting of the key was successful; < 0 if an error occurred | |
225 | */ | |
226 | int crypto_aead_setkey(struct crypto_aead *tfm, | |
227 | const u8 *key, unsigned int keylen); | |
228 | ||
229 | /** | |
230 | * crypto_aead_setauthsize() - set authentication data size | |
231 | * @tfm: cipher handle | |
232 | * @authsize: size of the authentication data / tag in bytes | |
233 | * | |
234 | * Set the authentication data size / tag size. AEAD requires an authentication | |
235 | * tag (or MAC) in addition to the associated data. | |
236 | * | |
237 | * Return: 0 if the setting of the key was successful; < 0 if an error occurred | |
238 | */ | |
239 | int crypto_aead_setauthsize(struct crypto_aead *tfm, unsigned int authsize); | |
240 | ||
241 | static inline struct crypto_aead *crypto_aead_reqtfm(struct aead_request *req) | |
242 | { | |
243 | return __crypto_aead_cast(req->base.tfm); | |
244 | } | |
245 | ||
246 | /** | |
247 | * crypto_aead_encrypt() - encrypt plaintext | |
248 | * @req: reference to the aead_request handle that holds all information | |
249 | * needed to perform the cipher operation | |
250 | * | |
251 | * Encrypt plaintext data using the aead_request handle. That data structure | |
252 | * and how it is filled with data is discussed with the aead_request_* | |
253 | * functions. | |
254 | * | |
255 | * IMPORTANT NOTE The encryption operation creates the authentication data / | |
256 | * tag. That data is concatenated with the created ciphertext. | |
257 | * The ciphertext memory size is therefore the given number of | |
258 | * block cipher blocks + the size defined by the | |
259 | * crypto_aead_setauthsize invocation. The caller must ensure | |
260 | * that sufficient memory is available for the ciphertext and | |
261 | * the authentication tag. | |
262 | * | |
263 | * Return: 0 if the cipher operation was successful; < 0 if an error occurred | |
264 | */ | |
265 | static inline int crypto_aead_encrypt(struct aead_request *req) | |
266 | { | |
267 | return crypto_aead_reqtfm(req)->encrypt(req); | |
268 | } | |
269 | ||
270 | /** | |
271 | * crypto_aead_decrypt() - decrypt ciphertext | |
272 | * @req: reference to the ablkcipher_request handle that holds all information | |
273 | * needed to perform the cipher operation | |
274 | * | |
275 | * Decrypt ciphertext data using the aead_request handle. That data structure | |
276 | * and how it is filled with data is discussed with the aead_request_* | |
277 | * functions. | |
278 | * | |
279 | * IMPORTANT NOTE The caller must concatenate the ciphertext followed by the | |
280 | * authentication data / tag. That authentication data / tag | |
281 | * must have the size defined by the crypto_aead_setauthsize | |
282 | * invocation. | |
283 | * | |
284 | * | |
285 | * Return: 0 if the cipher operation was successful; -EBADMSG: The AEAD | |
286 | * cipher operation performs the authentication of the data during the | |
287 | * decryption operation. Therefore, the function returns this error if | |
288 | * the authentication of the ciphertext was unsuccessful (i.e. the | |
289 | * integrity of the ciphertext or the associated data was violated); | |
290 | * < 0 if an error occurred. | |
291 | */ | |
292 | static inline int crypto_aead_decrypt(struct aead_request *req) | |
293 | { | |
294 | if (req->cryptlen < crypto_aead_authsize(crypto_aead_reqtfm(req))) | |
295 | return -EINVAL; | |
296 | ||
297 | return crypto_aead_reqtfm(req)->decrypt(req); | |
298 | } | |
299 | ||
300 | /** | |
301 | * DOC: Asynchronous AEAD Request Handle | |
302 | * | |
303 | * The aead_request data structure contains all pointers to data required for | |
304 | * the AEAD cipher operation. This includes the cipher handle (which can be | |
305 | * used by multiple aead_request instances), pointer to plaintext and | |
306 | * ciphertext, asynchronous callback function, etc. It acts as a handle to the | |
307 | * aead_request_* API calls in a similar way as AEAD handle to the | |
308 | * crypto_aead_* API calls. | |
309 | */ | |
310 | ||
311 | /** | |
312 | * crypto_aead_reqsize() - obtain size of the request data structure | |
313 | * @tfm: cipher handle | |
314 | * | |
315 | * Return: number of bytes | |
316 | */ | |
317 | static inline unsigned int crypto_aead_reqsize(struct crypto_aead *tfm) | |
318 | { | |
319 | return tfm->reqsize; | |
320 | } | |
321 | ||
322 | /** | |
323 | * aead_request_set_tfm() - update cipher handle reference in request | |
324 | * @req: request handle to be modified | |
325 | * @tfm: cipher handle that shall be added to the request handle | |
326 | * | |
327 | * Allow the caller to replace the existing aead handle in the request | |
328 | * data structure with a different one. | |
329 | */ | |
330 | static inline void aead_request_set_tfm(struct aead_request *req, | |
331 | struct crypto_aead *tfm) | |
332 | { | |
333 | req->base.tfm = crypto_aead_tfm(tfm->child); | |
334 | } | |
335 | ||
336 | /** | |
337 | * aead_request_alloc() - allocate request data structure | |
338 | * @tfm: cipher handle to be registered with the request | |
339 | * @gfp: memory allocation flag that is handed to kmalloc by the API call. | |
340 | * | |
341 | * Allocate the request data structure that must be used with the AEAD | |
342 | * encrypt and decrypt API calls. During the allocation, the provided aead | |
343 | * handle is registered in the request data structure. | |
344 | * | |
345 | * Return: allocated request handle in case of success; IS_ERR() is true in case | |
346 | * of an error, PTR_ERR() returns the error code. | |
347 | */ | |
348 | static inline struct aead_request *aead_request_alloc(struct crypto_aead *tfm, | |
349 | gfp_t gfp) | |
350 | { | |
351 | struct aead_request *req; | |
352 | ||
353 | req = kmalloc(sizeof(*req) + crypto_aead_reqsize(tfm), gfp); | |
354 | ||
355 | if (likely(req)) | |
356 | aead_request_set_tfm(req, tfm); | |
357 | ||
358 | return req; | |
359 | } | |
360 | ||
361 | /** | |
362 | * aead_request_free() - zeroize and free request data structure | |
363 | * @req: request data structure cipher handle to be freed | |
364 | */ | |
365 | static inline void aead_request_free(struct aead_request *req) | |
366 | { | |
367 | kzfree(req); | |
368 | } | |
369 | ||
370 | /** | |
371 | * aead_request_set_callback() - set asynchronous callback function | |
372 | * @req: request handle | |
373 | * @flags: specify zero or an ORing of the flags | |
374 | * CRYPTO_TFM_REQ_MAY_BACKLOG the request queue may back log and | |
375 | * increase the wait queue beyond the initial maximum size; | |
376 | * CRYPTO_TFM_REQ_MAY_SLEEP the request processing may sleep | |
377 | * @compl: callback function pointer to be registered with the request handle | |
378 | * @data: The data pointer refers to memory that is not used by the kernel | |
379 | * crypto API, but provided to the callback function for it to use. Here, | |
380 | * the caller can provide a reference to memory the callback function can | |
381 | * operate on. As the callback function is invoked asynchronously to the | |
382 | * related functionality, it may need to access data structures of the | |
383 | * related functionality which can be referenced using this pointer. The | |
384 | * callback function can access the memory via the "data" field in the | |
385 | * crypto_async_request data structure provided to the callback function. | |
386 | * | |
387 | * Setting the callback function that is triggered once the cipher operation | |
388 | * completes | |
389 | * | |
390 | * The callback function is registered with the aead_request handle and | |
391 | * must comply with the following template | |
392 | * | |
393 | * void callback_function(struct crypto_async_request *req, int error) | |
394 | */ | |
395 | static inline void aead_request_set_callback(struct aead_request *req, | |
396 | u32 flags, | |
397 | crypto_completion_t compl, | |
398 | void *data) | |
399 | { | |
400 | req->base.complete = compl; | |
401 | req->base.data = data; | |
402 | req->base.flags = flags; | |
403 | } | |
404 | ||
405 | /** | |
406 | * aead_request_set_crypt - set data buffers | |
407 | * @req: request handle | |
408 | * @src: source scatter / gather list | |
409 | * @dst: destination scatter / gather list | |
410 | * @cryptlen: number of bytes to process from @src | |
411 | * @iv: IV for the cipher operation which must comply with the IV size defined | |
412 | * by crypto_aead_ivsize() | |
413 | * | |
414 | * Setting the source data and destination data scatter / gather lists. | |
415 | * | |
416 | * For encryption, the source is treated as the plaintext and the | |
417 | * destination is the ciphertext. For a decryption operation, the use is | |
418 | * reversed - the source is the ciphertext and the destination is the plaintext. | |
419 | * | |
420 | * IMPORTANT NOTE AEAD requires an authentication tag (MAC). For decryption, | |
421 | * the caller must concatenate the ciphertext followed by the | |
422 | * authentication tag and provide the entire data stream to the | |
423 | * decryption operation (i.e. the data length used for the | |
424 | * initialization of the scatterlist and the data length for the | |
425 | * decryption operation is identical). For encryption, however, | |
426 | * the authentication tag is created while encrypting the data. | |
427 | * The destination buffer must hold sufficient space for the | |
428 | * ciphertext and the authentication tag while the encryption | |
429 | * invocation must only point to the plaintext data size. The | |
430 | * following code snippet illustrates the memory usage | |
431 | * buffer = kmalloc(ptbuflen + (enc ? authsize : 0)); | |
432 | * sg_init_one(&sg, buffer, ptbuflen + (enc ? authsize : 0)); | |
433 | * aead_request_set_crypt(req, &sg, &sg, ptbuflen, iv); | |
434 | */ | |
435 | static inline void aead_request_set_crypt(struct aead_request *req, | |
436 | struct scatterlist *src, | |
437 | struct scatterlist *dst, | |
438 | unsigned int cryptlen, u8 *iv) | |
439 | { | |
440 | req->src = src; | |
441 | req->dst = dst; | |
442 | req->cryptlen = cryptlen; | |
443 | req->iv = iv; | |
444 | } | |
445 | ||
446 | /** | |
447 | * aead_request_set_assoc() - set the associated data scatter / gather list | |
448 | * @req: request handle | |
449 | * @assoc: associated data scatter / gather list | |
450 | * @assoclen: number of bytes to process from @assoc | |
451 | * | |
452 | * For encryption, the memory is filled with the associated data. For | |
453 | * decryption, the memory must point to the associated data. | |
454 | */ | |
455 | static inline void aead_request_set_assoc(struct aead_request *req, | |
456 | struct scatterlist *assoc, | |
457 | unsigned int assoclen) | |
458 | { | |
459 | req->assoc = assoc; | |
460 | req->assoclen = assoclen; | |
461 | } | |
462 | ||
743edf57 HX |
463 | static inline struct crypto_aead *aead_givcrypt_reqtfm( |
464 | struct aead_givcrypt_request *req) | |
465 | { | |
466 | return crypto_aead_reqtfm(&req->areq); | |
467 | } | |
468 | ||
3a282bd2 HX |
469 | static inline int crypto_aead_givencrypt(struct aead_givcrypt_request *req) |
470 | { | |
5d1d65f8 | 471 | return aead_givcrypt_reqtfm(req)->givencrypt(req); |
3a282bd2 HX |
472 | }; |
473 | ||
474 | static inline int crypto_aead_givdecrypt(struct aead_givcrypt_request *req) | |
475 | { | |
5d1d65f8 | 476 | return aead_givcrypt_reqtfm(req)->givdecrypt(req); |
3a282bd2 HX |
477 | }; |
478 | ||
479 | static inline void aead_givcrypt_set_tfm(struct aead_givcrypt_request *req, | |
480 | struct crypto_aead *tfm) | |
481 | { | |
482 | req->areq.base.tfm = crypto_aead_tfm(tfm); | |
483 | } | |
484 | ||
485 | static inline struct aead_givcrypt_request *aead_givcrypt_alloc( | |
486 | struct crypto_aead *tfm, gfp_t gfp) | |
487 | { | |
488 | struct aead_givcrypt_request *req; | |
489 | ||
490 | req = kmalloc(sizeof(struct aead_givcrypt_request) + | |
491 | crypto_aead_reqsize(tfm), gfp); | |
492 | ||
493 | if (likely(req)) | |
494 | aead_givcrypt_set_tfm(req, tfm); | |
495 | ||
496 | return req; | |
497 | } | |
498 | ||
499 | static inline void aead_givcrypt_free(struct aead_givcrypt_request *req) | |
500 | { | |
501 | kfree(req); | |
502 | } | |
503 | ||
504 | static inline void aead_givcrypt_set_callback( | |
505 | struct aead_givcrypt_request *req, u32 flags, | |
3e3dc25f | 506 | crypto_completion_t compl, void *data) |
3a282bd2 | 507 | { |
3e3dc25f | 508 | aead_request_set_callback(&req->areq, flags, compl, data); |
3a282bd2 HX |
509 | } |
510 | ||
511 | static inline void aead_givcrypt_set_crypt(struct aead_givcrypt_request *req, | |
512 | struct scatterlist *src, | |
513 | struct scatterlist *dst, | |
514 | unsigned int nbytes, void *iv) | |
515 | { | |
516 | aead_request_set_crypt(&req->areq, src, dst, nbytes, iv); | |
517 | } | |
518 | ||
519 | static inline void aead_givcrypt_set_assoc(struct aead_givcrypt_request *req, | |
520 | struct scatterlist *assoc, | |
521 | unsigned int assoclen) | |
522 | { | |
523 | aead_request_set_assoc(&req->areq, assoc, assoclen); | |
524 | } | |
525 | ||
526 | static inline void aead_givcrypt_set_giv(struct aead_givcrypt_request *req, | |
527 | u8 *giv, u64 seq) | |
528 | { | |
529 | req->giv = giv; | |
530 | req->seq = seq; | |
531 | } | |
532 | ||
743edf57 | 533 | #endif /* _CRYPTO_AEAD_H */ |