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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/*
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 ablkcipher_alg
116 * @encrypt: see struct ablkcipher_alg
117 * @decrypt: see struct ablkcipher_alg
118 * @geniv: see struct ablkcipher_alg
119 * @ivsize: see struct ablkcipher_alg
120 * @init: Initialize the cryptographic transformation object. This function
121 * is used to initialize the cryptographic transformation object.
122 * This function is called only once at the instantiation time, right
123 * after the transformation context was allocated. In case the
124 * cryptographic hardware has some special requirements which need to
125 * be handled by software, this function shall check for the precise
126 * requirement of the transformation and put any software fallbacks
127 * in place.
128 * @exit: Deinitialize the cryptographic transformation object. This is a
129 * counterpart to @init, used to remove various changes set in
130 * @init.
131 * @base: Definition of a generic crypto cipher algorithm.
132 *
133 * All fields except @ivsize is mandatory and must be filled.
134 */
135struct aead_alg {
136 int (*setkey)(struct crypto_aead *tfm, const u8 *key,
137 unsigned int keylen);
138 int (*setauthsize)(struct crypto_aead *tfm, unsigned int authsize);
139 int (*encrypt)(struct aead_request *req);
140 int (*decrypt)(struct aead_request *req);
141 int (*init)(struct crypto_aead *tfm);
142 void (*exit)(struct crypto_aead *tfm);
143
144 const char *geniv;
145
146 unsigned int ivsize;
147 unsigned int maxauthsize;
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
236/**
237 * crypto_aead_blocksize() - obtain block size of cipher
238 * @tfm: cipher handle
239 *
240 * The block size for the AEAD referenced with the cipher handle is returned.
241 * The caller may use that information to allocate appropriate memory for the
242 * data returned by the encryption or decryption operation
243 *
244 * Return: block size of cipher
245 */
246static inline unsigned int crypto_aead_blocksize(struct crypto_aead *tfm)
247{
248 return crypto_tfm_alg_blocksize(crypto_aead_tfm(tfm));
249}
250
251static inline unsigned int crypto_aead_alignmask(struct crypto_aead *tfm)
252{
253 return crypto_tfm_alg_alignmask(crypto_aead_tfm(tfm));
254}
255
256static inline u32 crypto_aead_get_flags(struct crypto_aead *tfm)
257{
258 return crypto_tfm_get_flags(crypto_aead_tfm(tfm));
259}
260
261static inline void crypto_aead_set_flags(struct crypto_aead *tfm, u32 flags)
262{
263 crypto_tfm_set_flags(crypto_aead_tfm(tfm), flags);
264}
265
266static inline void crypto_aead_clear_flags(struct crypto_aead *tfm, u32 flags)
267{
268 crypto_tfm_clear_flags(crypto_aead_tfm(tfm), flags);
269}
270
271/**
272 * crypto_aead_setkey() - set key for cipher
273 * @tfm: cipher handle
274 * @key: buffer holding the key
275 * @keylen: length of the key in bytes
276 *
277 * The caller provided key is set for the AEAD referenced by the cipher
278 * handle.
279 *
280 * Note, the key length determines the cipher type. Many block ciphers implement
281 * different cipher modes depending on the key size, such as AES-128 vs AES-192
282 * vs. AES-256. When providing a 16 byte key for an AES cipher handle, AES-128
283 * is performed.
284 *
285 * Return: 0 if the setting of the key was successful; < 0 if an error occurred
286 */
287int crypto_aead_setkey(struct crypto_aead *tfm,
288 const u8 *key, unsigned int keylen);
289
290/**
291 * crypto_aead_setauthsize() - set authentication data size
292 * @tfm: cipher handle
293 * @authsize: size of the authentication data / tag in bytes
294 *
295 * Set the authentication data size / tag size. AEAD requires an authentication
296 * tag (or MAC) in addition to the associated data.
297 *
298 * Return: 0 if the setting of the key was successful; < 0 if an error occurred
299 */
300int crypto_aead_setauthsize(struct crypto_aead *tfm, unsigned int authsize);
301
302static inline struct crypto_aead *crypto_aead_reqtfm(struct aead_request *req)
303{
304 return __crypto_aead_cast(req->base.tfm);
305}
306
307/**
308 * crypto_aead_encrypt() - encrypt plaintext
309 * @req: reference to the aead_request handle that holds all information
310 * needed to perform the cipher operation
311 *
312 * Encrypt plaintext data using the aead_request handle. That data structure
313 * and how it is filled with data is discussed with the aead_request_*
314 * functions.
315 *
316 * IMPORTANT NOTE The encryption operation creates the authentication data /
317 * tag. That data is concatenated with the created ciphertext.
318 * The ciphertext memory size is therefore the given number of
319 * block cipher blocks + the size defined by the
320 * crypto_aead_setauthsize invocation. The caller must ensure
321 * that sufficient memory is available for the ciphertext and
322 * the authentication tag.
323 *
324 * Return: 0 if the cipher operation was successful; < 0 if an error occurred
325 */
326static inline int crypto_aead_encrypt(struct aead_request *req)
327{
328 return crypto_aead_alg(crypto_aead_reqtfm(req))->encrypt(req);
329}
330
331/**
332 * crypto_aead_decrypt() - decrypt ciphertext
333 * @req: reference to the ablkcipher_request handle that holds all information
334 * needed to perform the cipher operation
335 *
336 * Decrypt ciphertext data using the aead_request handle. That data structure
337 * and how it is filled with data is discussed with the aead_request_*
338 * functions.
339 *
340 * IMPORTANT NOTE The caller must concatenate the ciphertext followed by the
341 * authentication data / tag. That authentication data / tag
342 * must have the size defined by the crypto_aead_setauthsize
343 * invocation.
344 *
345 *
346 * Return: 0 if the cipher operation was successful; -EBADMSG: The AEAD
347 * cipher operation performs the authentication of the data during the
348 * decryption operation. Therefore, the function returns this error if
349 * the authentication of the ciphertext was unsuccessful (i.e. the
350 * integrity of the ciphertext or the associated data was violated);
351 * < 0 if an error occurred.
352 */
353static inline int crypto_aead_decrypt(struct aead_request *req)
354{
355 struct crypto_aead *aead = crypto_aead_reqtfm(req);
356
357 if (req->cryptlen < crypto_aead_authsize(aead))
358 return -EINVAL;
359
360 return crypto_aead_alg(aead)->decrypt(req);
361}
362
363/**
364 * DOC: Asynchronous AEAD Request Handle
365 *
366 * The aead_request data structure contains all pointers to data required for
367 * the AEAD cipher operation. This includes the cipher handle (which can be
368 * used by multiple aead_request instances), pointer to plaintext and
369 * ciphertext, asynchronous callback function, etc. It acts as a handle to the
370 * aead_request_* API calls in a similar way as AEAD handle to the
371 * crypto_aead_* API calls.
372 */
373
374/**
375 * crypto_aead_reqsize() - obtain size of the request data structure
376 * @tfm: cipher handle
377 *
378 * Return: number of bytes
379 */
380static inline unsigned int crypto_aead_reqsize(struct crypto_aead *tfm)
381{
382 return tfm->reqsize;
383}
384
385/**
386 * aead_request_set_tfm() - update cipher handle reference in request
387 * @req: request handle to be modified
388 * @tfm: cipher handle that shall be added to the request handle
389 *
390 * Allow the caller to replace the existing aead handle in the request
391 * data structure with a different one.
392 */
393static inline void aead_request_set_tfm(struct aead_request *req,
394 struct crypto_aead *tfm)
395{
396 req->base.tfm = crypto_aead_tfm(tfm);
397}
398
399/**
400 * aead_request_alloc() - allocate request data structure
401 * @tfm: cipher handle to be registered with the request
402 * @gfp: memory allocation flag that is handed to kmalloc by the API call.
403 *
404 * Allocate the request data structure that must be used with the AEAD
405 * encrypt and decrypt API calls. During the allocation, the provided aead
406 * handle is registered in the request data structure.
407 *
408 * Return: allocated request handle in case of success; IS_ERR() is true in case
409 * of an error, PTR_ERR() returns the error code.
410 */
411static inline struct aead_request *aead_request_alloc(struct crypto_aead *tfm,
412 gfp_t gfp)
413{
414 struct aead_request *req;
415
416 req = kmalloc(sizeof(*req) + crypto_aead_reqsize(tfm), gfp);
417
418 if (likely(req))
419 aead_request_set_tfm(req, tfm);
420
421 return req;
422}
423
424/**
425 * aead_request_free() - zeroize and free request data structure
426 * @req: request data structure cipher handle to be freed
427 */
428static inline void aead_request_free(struct aead_request *req)
429{
430 kzfree(req);
431}
432
433/**
434 * aead_request_set_callback() - set asynchronous callback function
435 * @req: request handle
436 * @flags: specify zero or an ORing of the flags
437 * CRYPTO_TFM_REQ_MAY_BACKLOG the request queue may back log and
438 * increase the wait queue beyond the initial maximum size;
439 * CRYPTO_TFM_REQ_MAY_SLEEP the request processing may sleep
440 * @compl: callback function pointer to be registered with the request handle
441 * @data: The data pointer refers to memory that is not used by the kernel
442 * crypto API, but provided to the callback function for it to use. Here,
443 * the caller can provide a reference to memory the callback function can
444 * operate on. As the callback function is invoked asynchronously to the
445 * related functionality, it may need to access data structures of the
446 * related functionality which can be referenced using this pointer. The
447 * callback function can access the memory via the "data" field in the
448 * crypto_async_request data structure provided to the callback function.
449 *
450 * Setting the callback function that is triggered once the cipher operation
451 * completes
452 *
453 * The callback function is registered with the aead_request handle and
454 * must comply with the following template
455 *
456 * void callback_function(struct crypto_async_request *req, int error)
457 */
458static inline void aead_request_set_callback(struct aead_request *req,
459 u32 flags,
460 crypto_completion_t compl,
461 void *data)
462{
463 req->base.complete = compl;
464 req->base.data = data;
465 req->base.flags = flags;
466}
467
468/**
469 * aead_request_set_crypt - set data buffers
470 * @req: request handle
471 * @src: source scatter / gather list
472 * @dst: destination scatter / gather list
473 * @cryptlen: number of bytes to process from @src
474 * @iv: IV for the cipher operation which must comply with the IV size defined
475 * by crypto_aead_ivsize()
476 *
477 * Setting the source data and destination data scatter / gather lists which
478 * hold the associated data concatenated with the plaintext or ciphertext. See
479 * below for the authentication tag.
480 *
481 * For encryption, the source is treated as the plaintext and the
482 * destination is the ciphertext. For a decryption operation, the use is
483 * reversed - the source is the ciphertext and the destination is the plaintext.
484 *
485 * For both src/dst the layout is associated data, plain/cipher text,
486 * authentication tag.
487 *
488 * The content of the AD in the destination buffer after processing
489 * will either be untouched, or it will contain a copy of the AD
490 * from the source buffer. In order to ensure that it always has
491 * a copy of the AD, the user must copy the AD over either before
492 * or after processing. Of course this is not relevant if the user
493 * is doing in-place processing where src == dst.
494 *
495 * IMPORTANT NOTE AEAD requires an authentication tag (MAC). For decryption,
496 * the caller must concatenate the ciphertext followed by the
497 * authentication tag and provide the entire data stream to the
498 * decryption operation (i.e. the data length used for the
499 * initialization of the scatterlist and the data length for the
500 * decryption operation is identical). For encryption, however,
501 * the authentication tag is created while encrypting the data.
502 * The destination buffer must hold sufficient space for the
503 * ciphertext and the authentication tag while the encryption
504 * invocation must only point to the plaintext data size. The
505 * following code snippet illustrates the memory usage
506 * buffer = kmalloc(ptbuflen + (enc ? authsize : 0));
507 * sg_init_one(&sg, buffer, ptbuflen + (enc ? authsize : 0));
508 * aead_request_set_crypt(req, &sg, &sg, ptbuflen, iv);
509 */
510static inline void aead_request_set_crypt(struct aead_request *req,
511 struct scatterlist *src,
512 struct scatterlist *dst,
513 unsigned int cryptlen, u8 *iv)
514{
515 req->src = src;
516 req->dst = dst;
517 req->cryptlen = cryptlen;
518 req->iv = iv;
519}
520
521/**
522 * aead_request_set_ad - set associated data information
523 * @req: request handle
524 * @assoclen: number of bytes in associated data
525 *
526 * Setting the AD information. This function sets the length of
527 * the associated data.
528 */
529static inline void aead_request_set_ad(struct aead_request *req,
530 unsigned int assoclen)
531{
532 req->assoclen = assoclen;
533}
534
535#endif /* _CRYPTO_AEAD_H */