skcipher.h 20 KB

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  1. /*
  2. * Symmetric key ciphers.
  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. #ifndef _CRYPTO_SKCIPHER_H
  13. #define _CRYPTO_SKCIPHER_H
  14. #include <linux/crypto.h>
  15. #include <linux/kernel.h>
  16. #include <linux/slab.h>
  17. /**
  18. * struct skcipher_request - Symmetric key cipher request
  19. * @cryptlen: Number of bytes to encrypt or decrypt
  20. * @iv: Initialisation Vector
  21. * @src: Source SG list
  22. * @dst: Destination SG list
  23. * @base: Underlying async request request
  24. * @__ctx: Start of private context data
  25. */
  26. struct skcipher_request {
  27. unsigned int cryptlen;
  28. u8 *iv;
  29. struct scatterlist *src;
  30. struct scatterlist *dst;
  31. struct crypto_async_request base;
  32. void *__ctx[] CRYPTO_MINALIGN_ATTR;
  33. };
  34. /**
  35. * struct skcipher_givcrypt_request - Crypto request with IV generation
  36. * @seq: Sequence number for IV generation
  37. * @giv: Space for generated IV
  38. * @creq: The crypto request itself
  39. */
  40. struct skcipher_givcrypt_request {
  41. u64 seq;
  42. u8 *giv;
  43. struct ablkcipher_request creq;
  44. };
  45. struct crypto_skcipher {
  46. int (*setkey)(struct crypto_skcipher *tfm, const u8 *key,
  47. unsigned int keylen);
  48. int (*encrypt)(struct skcipher_request *req);
  49. int (*decrypt)(struct skcipher_request *req);
  50. unsigned int ivsize;
  51. unsigned int reqsize;
  52. unsigned int keysize;
  53. struct crypto_tfm base;
  54. };
  55. /**
  56. * struct skcipher_alg - symmetric key cipher definition
  57. * @min_keysize: Minimum key size supported by the transformation. This is the
  58. * smallest key length supported by this transformation algorithm.
  59. * This must be set to one of the pre-defined values as this is
  60. * not hardware specific. Possible values for this field can be
  61. * found via git grep "_MIN_KEY_SIZE" include/crypto/
  62. * @max_keysize: Maximum key size supported by the transformation. This is the
  63. * largest key length supported by this transformation algorithm.
  64. * This must be set to one of the pre-defined values as this is
  65. * not hardware specific. Possible values for this field can be
  66. * found via git grep "_MAX_KEY_SIZE" include/crypto/
  67. * @setkey: Set key for the transformation. This function is used to either
  68. * program a supplied key into the hardware or store the key in the
  69. * transformation context for programming it later. Note that this
  70. * function does modify the transformation context. This function can
  71. * be called multiple times during the existence of the transformation
  72. * object, so one must make sure the key is properly reprogrammed into
  73. * the hardware. This function is also responsible for checking the key
  74. * length for validity. In case a software fallback was put in place in
  75. * the @cra_init call, this function might need to use the fallback if
  76. * the algorithm doesn't support all of the key sizes.
  77. * @encrypt: Encrypt a scatterlist of blocks. This function is used to encrypt
  78. * the supplied scatterlist containing the blocks of data. The crypto
  79. * API consumer is responsible for aligning the entries of the
  80. * scatterlist properly and making sure the chunks are correctly
  81. * sized. In case a software fallback was put in place in the
  82. * @cra_init call, this function might need to use the fallback if
  83. * the algorithm doesn't support all of the key sizes. In case the
  84. * key was stored in transformation context, the key might need to be
  85. * re-programmed into the hardware in this function. This function
  86. * shall not modify the transformation context, as this function may
  87. * be called in parallel with the same transformation object.
  88. * @decrypt: Decrypt a single block. This is a reverse counterpart to @encrypt
  89. * and the conditions are exactly the same.
  90. * @init: Initialize the cryptographic transformation object. This function
  91. * is used to initialize the cryptographic transformation object.
  92. * This function is called only once at the instantiation time, right
  93. * after the transformation context was allocated. In case the
  94. * cryptographic hardware has some special requirements which need to
  95. * be handled by software, this function shall check for the precise
  96. * requirement of the transformation and put any software fallbacks
  97. * in place.
  98. * @exit: Deinitialize the cryptographic transformation object. This is a
  99. * counterpart to @init, used to remove various changes set in
  100. * @init.
  101. * @ivsize: IV size applicable for transformation. The consumer must provide an
  102. * IV of exactly that size to perform the encrypt or decrypt operation.
  103. * @chunksize: Equal to the block size except for stream ciphers such as
  104. * CTR where it is set to the underlying block size.
  105. * @base: Definition of a generic crypto algorithm.
  106. *
  107. * All fields except @ivsize are mandatory and must be filled.
  108. */
  109. struct skcipher_alg {
  110. int (*setkey)(struct crypto_skcipher *tfm, const u8 *key,
  111. unsigned int keylen);
  112. int (*encrypt)(struct skcipher_request *req);
  113. int (*decrypt)(struct skcipher_request *req);
  114. int (*init)(struct crypto_skcipher *tfm);
  115. void (*exit)(struct crypto_skcipher *tfm);
  116. unsigned int min_keysize;
  117. unsigned int max_keysize;
  118. unsigned int ivsize;
  119. unsigned int chunksize;
  120. struct crypto_alg base;
  121. };
  122. #define SKCIPHER_REQUEST_ON_STACK(name, tfm) \
  123. char __##name##_desc[sizeof(struct skcipher_request) + \
  124. crypto_skcipher_reqsize(tfm)] CRYPTO_MINALIGN_ATTR; \
  125. struct skcipher_request *name = (void *)__##name##_desc
  126. /**
  127. * DOC: Symmetric Key Cipher API
  128. *
  129. * Symmetric key cipher API is used with the ciphers of type
  130. * CRYPTO_ALG_TYPE_SKCIPHER (listed as type "skcipher" in /proc/crypto).
  131. *
  132. * Asynchronous cipher operations imply that the function invocation for a
  133. * cipher request returns immediately before the completion of the operation.
  134. * The cipher request is scheduled as a separate kernel thread and therefore
  135. * load-balanced on the different CPUs via the process scheduler. To allow
  136. * the kernel crypto API to inform the caller about the completion of a cipher
  137. * request, the caller must provide a callback function. That function is
  138. * invoked with the cipher handle when the request completes.
  139. *
  140. * To support the asynchronous operation, additional information than just the
  141. * cipher handle must be supplied to the kernel crypto API. That additional
  142. * information is given by filling in the skcipher_request data structure.
  143. *
  144. * For the symmetric key cipher API, the state is maintained with the tfm
  145. * cipher handle. A single tfm can be used across multiple calls and in
  146. * parallel. For asynchronous block cipher calls, context data supplied and
  147. * only used by the caller can be referenced the request data structure in
  148. * addition to the IV used for the cipher request. The maintenance of such
  149. * state information would be important for a crypto driver implementer to
  150. * have, because when calling the callback function upon completion of the
  151. * cipher operation, that callback function may need some information about
  152. * which operation just finished if it invoked multiple in parallel. This
  153. * state information is unused by the kernel crypto API.
  154. */
  155. static inline struct crypto_skcipher *__crypto_skcipher_cast(
  156. struct crypto_tfm *tfm)
  157. {
  158. return container_of(tfm, struct crypto_skcipher, base);
  159. }
  160. /**
  161. * crypto_alloc_skcipher() - allocate symmetric key cipher handle
  162. * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
  163. * skcipher cipher
  164. * @type: specifies the type of the cipher
  165. * @mask: specifies the mask for the cipher
  166. *
  167. * Allocate a cipher handle for an skcipher. The returned struct
  168. * crypto_skcipher is the cipher handle that is required for any subsequent
  169. * API invocation for that skcipher.
  170. *
  171. * Return: allocated cipher handle in case of success; IS_ERR() is true in case
  172. * of an error, PTR_ERR() returns the error code.
  173. */
  174. struct crypto_skcipher *crypto_alloc_skcipher(const char *alg_name,
  175. u32 type, u32 mask);
  176. static inline struct crypto_tfm *crypto_skcipher_tfm(
  177. struct crypto_skcipher *tfm)
  178. {
  179. return &tfm->base;
  180. }
  181. /**
  182. * crypto_free_skcipher() - zeroize and free cipher handle
  183. * @tfm: cipher handle to be freed
  184. */
  185. static inline void crypto_free_skcipher(struct crypto_skcipher *tfm)
  186. {
  187. crypto_destroy_tfm(tfm, crypto_skcipher_tfm(tfm));
  188. }
  189. /**
  190. * crypto_has_skcipher() - Search for the availability of an skcipher.
  191. * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
  192. * skcipher
  193. * @type: specifies the type of the cipher
  194. * @mask: specifies the mask for the cipher
  195. *
  196. * Return: true when the skcipher is known to the kernel crypto API; false
  197. * otherwise
  198. */
  199. static inline int crypto_has_skcipher(const char *alg_name, u32 type,
  200. u32 mask)
  201. {
  202. return crypto_has_alg(alg_name, crypto_skcipher_type(type),
  203. crypto_skcipher_mask(mask));
  204. }
  205. /**
  206. * crypto_has_skcipher2() - Search for the availability of an skcipher.
  207. * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
  208. * skcipher
  209. * @type: specifies the type of the skcipher
  210. * @mask: specifies the mask for the skcipher
  211. *
  212. * Return: true when the skcipher is known to the kernel crypto API; false
  213. * otherwise
  214. */
  215. int crypto_has_skcipher2(const char *alg_name, u32 type, u32 mask);
  216. static inline const char *crypto_skcipher_driver_name(
  217. struct crypto_skcipher *tfm)
  218. {
  219. return crypto_tfm_alg_driver_name(crypto_skcipher_tfm(tfm));
  220. }
  221. static inline struct skcipher_alg *crypto_skcipher_alg(
  222. struct crypto_skcipher *tfm)
  223. {
  224. return container_of(crypto_skcipher_tfm(tfm)->__crt_alg,
  225. struct skcipher_alg, base);
  226. }
  227. static inline unsigned int crypto_skcipher_alg_ivsize(struct skcipher_alg *alg)
  228. {
  229. if ((alg->base.cra_flags & CRYPTO_ALG_TYPE_MASK) ==
  230. CRYPTO_ALG_TYPE_BLKCIPHER)
  231. return alg->base.cra_blkcipher.ivsize;
  232. if (alg->base.cra_ablkcipher.encrypt)
  233. return alg->base.cra_ablkcipher.ivsize;
  234. return alg->ivsize;
  235. }
  236. /**
  237. * crypto_skcipher_ivsize() - obtain IV size
  238. * @tfm: cipher handle
  239. *
  240. * The size of the IV for the skcipher referenced by the cipher handle is
  241. * returned. This IV size may be zero if the cipher does not need an IV.
  242. *
  243. * Return: IV size in bytes
  244. */
  245. static inline unsigned int crypto_skcipher_ivsize(struct crypto_skcipher *tfm)
  246. {
  247. return tfm->ivsize;
  248. }
  249. static inline unsigned int crypto_skcipher_alg_chunksize(
  250. struct skcipher_alg *alg)
  251. {
  252. if ((alg->base.cra_flags & CRYPTO_ALG_TYPE_MASK) ==
  253. CRYPTO_ALG_TYPE_BLKCIPHER)
  254. return alg->base.cra_blocksize;
  255. if (alg->base.cra_ablkcipher.encrypt)
  256. return alg->base.cra_blocksize;
  257. return alg->chunksize;
  258. }
  259. /**
  260. * crypto_skcipher_chunksize() - obtain chunk size
  261. * @tfm: cipher handle
  262. *
  263. * The block size is set to one for ciphers such as CTR. However,
  264. * you still need to provide incremental updates in multiples of
  265. * the underlying block size as the IV does not have sub-block
  266. * granularity. This is known in this API as the chunk size.
  267. *
  268. * Return: chunk size in bytes
  269. */
  270. static inline unsigned int crypto_skcipher_chunksize(
  271. struct crypto_skcipher *tfm)
  272. {
  273. return crypto_skcipher_alg_chunksize(crypto_skcipher_alg(tfm));
  274. }
  275. /**
  276. * crypto_skcipher_blocksize() - obtain block size of cipher
  277. * @tfm: cipher handle
  278. *
  279. * The block size for the skcipher referenced with the cipher handle is
  280. * returned. The caller may use that information to allocate appropriate
  281. * memory for the data returned by the encryption or decryption operation
  282. *
  283. * Return: block size of cipher
  284. */
  285. static inline unsigned int crypto_skcipher_blocksize(
  286. struct crypto_skcipher *tfm)
  287. {
  288. return crypto_tfm_alg_blocksize(crypto_skcipher_tfm(tfm));
  289. }
  290. static inline unsigned int crypto_skcipher_alignmask(
  291. struct crypto_skcipher *tfm)
  292. {
  293. return crypto_tfm_alg_alignmask(crypto_skcipher_tfm(tfm));
  294. }
  295. static inline u32 crypto_skcipher_get_flags(struct crypto_skcipher *tfm)
  296. {
  297. return crypto_tfm_get_flags(crypto_skcipher_tfm(tfm));
  298. }
  299. static inline void crypto_skcipher_set_flags(struct crypto_skcipher *tfm,
  300. u32 flags)
  301. {
  302. crypto_tfm_set_flags(crypto_skcipher_tfm(tfm), flags);
  303. }
  304. static inline void crypto_skcipher_clear_flags(struct crypto_skcipher *tfm,
  305. u32 flags)
  306. {
  307. crypto_tfm_clear_flags(crypto_skcipher_tfm(tfm), flags);
  308. }
  309. /**
  310. * crypto_skcipher_setkey() - set key for cipher
  311. * @tfm: cipher handle
  312. * @key: buffer holding the key
  313. * @keylen: length of the key in bytes
  314. *
  315. * The caller provided key is set for the skcipher referenced by the cipher
  316. * handle.
  317. *
  318. * Note, the key length determines the cipher type. Many block ciphers implement
  319. * different cipher modes depending on the key size, such as AES-128 vs AES-192
  320. * vs. AES-256. When providing a 16 byte key for an AES cipher handle, AES-128
  321. * is performed.
  322. *
  323. * Return: 0 if the setting of the key was successful; < 0 if an error occurred
  324. */
  325. static inline int crypto_skcipher_setkey(struct crypto_skcipher *tfm,
  326. const u8 *key, unsigned int keylen)
  327. {
  328. return tfm->setkey(tfm, key, keylen);
  329. }
  330. static inline bool crypto_skcipher_has_setkey(struct crypto_skcipher *tfm)
  331. {
  332. return tfm->keysize;
  333. }
  334. static inline unsigned int crypto_skcipher_default_keysize(
  335. struct crypto_skcipher *tfm)
  336. {
  337. return tfm->keysize;
  338. }
  339. /**
  340. * crypto_skcipher_reqtfm() - obtain cipher handle from request
  341. * @req: skcipher_request out of which the cipher handle is to be obtained
  342. *
  343. * Return the crypto_skcipher handle when furnishing an skcipher_request
  344. * data structure.
  345. *
  346. * Return: crypto_skcipher handle
  347. */
  348. static inline struct crypto_skcipher *crypto_skcipher_reqtfm(
  349. struct skcipher_request *req)
  350. {
  351. return __crypto_skcipher_cast(req->base.tfm);
  352. }
  353. /**
  354. * crypto_skcipher_encrypt() - encrypt plaintext
  355. * @req: reference to the skcipher_request handle that holds all information
  356. * needed to perform the cipher operation
  357. *
  358. * Encrypt plaintext data using the skcipher_request handle. That data
  359. * structure and how it is filled with data is discussed with the
  360. * skcipher_request_* functions.
  361. *
  362. * Return: 0 if the cipher operation was successful; < 0 if an error occurred
  363. */
  364. static inline int crypto_skcipher_encrypt(struct skcipher_request *req)
  365. {
  366. struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
  367. return tfm->encrypt(req);
  368. }
  369. /**
  370. * crypto_skcipher_decrypt() - decrypt ciphertext
  371. * @req: reference to the skcipher_request handle that holds all information
  372. * needed to perform the cipher operation
  373. *
  374. * Decrypt ciphertext data using the skcipher_request handle. That data
  375. * structure and how it is filled with data is discussed with the
  376. * skcipher_request_* functions.
  377. *
  378. * Return: 0 if the cipher operation was successful; < 0 if an error occurred
  379. */
  380. static inline int crypto_skcipher_decrypt(struct skcipher_request *req)
  381. {
  382. struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
  383. return tfm->decrypt(req);
  384. }
  385. /**
  386. * DOC: Symmetric Key Cipher Request Handle
  387. *
  388. * The skcipher_request data structure contains all pointers to data
  389. * required for the symmetric key cipher operation. This includes the cipher
  390. * handle (which can be used by multiple skcipher_request instances), pointer
  391. * to plaintext and ciphertext, asynchronous callback function, etc. It acts
  392. * as a handle to the skcipher_request_* API calls in a similar way as
  393. * skcipher handle to the crypto_skcipher_* API calls.
  394. */
  395. /**
  396. * crypto_skcipher_reqsize() - obtain size of the request data structure
  397. * @tfm: cipher handle
  398. *
  399. * Return: number of bytes
  400. */
  401. static inline unsigned int crypto_skcipher_reqsize(struct crypto_skcipher *tfm)
  402. {
  403. return tfm->reqsize;
  404. }
  405. /**
  406. * skcipher_request_set_tfm() - update cipher handle reference in request
  407. * @req: request handle to be modified
  408. * @tfm: cipher handle that shall be added to the request handle
  409. *
  410. * Allow the caller to replace the existing skcipher handle in the request
  411. * data structure with a different one.
  412. */
  413. static inline void skcipher_request_set_tfm(struct skcipher_request *req,
  414. struct crypto_skcipher *tfm)
  415. {
  416. req->base.tfm = crypto_skcipher_tfm(tfm);
  417. }
  418. static inline struct skcipher_request *skcipher_request_cast(
  419. struct crypto_async_request *req)
  420. {
  421. return container_of(req, struct skcipher_request, base);
  422. }
  423. /**
  424. * skcipher_request_alloc() - allocate request data structure
  425. * @tfm: cipher handle to be registered with the request
  426. * @gfp: memory allocation flag that is handed to kmalloc by the API call.
  427. *
  428. * Allocate the request data structure that must be used with the skcipher
  429. * encrypt and decrypt API calls. During the allocation, the provided skcipher
  430. * handle is registered in the request data structure.
  431. *
  432. * Return: allocated request handle in case of success, or NULL if out of memory
  433. */
  434. static inline struct skcipher_request *skcipher_request_alloc(
  435. struct crypto_skcipher *tfm, gfp_t gfp)
  436. {
  437. struct skcipher_request *req;
  438. req = kmalloc(sizeof(struct skcipher_request) +
  439. crypto_skcipher_reqsize(tfm), gfp);
  440. if (likely(req))
  441. skcipher_request_set_tfm(req, tfm);
  442. return req;
  443. }
  444. /**
  445. * skcipher_request_free() - zeroize and free request data structure
  446. * @req: request data structure cipher handle to be freed
  447. */
  448. static inline void skcipher_request_free(struct skcipher_request *req)
  449. {
  450. kzfree(req);
  451. }
  452. static inline void skcipher_request_zero(struct skcipher_request *req)
  453. {
  454. struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
  455. memzero_explicit(req, sizeof(*req) + crypto_skcipher_reqsize(tfm));
  456. }
  457. /**
  458. * skcipher_request_set_callback() - set asynchronous callback function
  459. * @req: request handle
  460. * @flags: specify zero or an ORing of the flags
  461. * CRYPTO_TFM_REQ_MAY_BACKLOG the request queue may back log and
  462. * increase the wait queue beyond the initial maximum size;
  463. * CRYPTO_TFM_REQ_MAY_SLEEP the request processing may sleep
  464. * @compl: callback function pointer to be registered with the request handle
  465. * @data: The data pointer refers to memory that is not used by the kernel
  466. * crypto API, but provided to the callback function for it to use. Here,
  467. * the caller can provide a reference to memory the callback function can
  468. * operate on. As the callback function is invoked asynchronously to the
  469. * related functionality, it may need to access data structures of the
  470. * related functionality which can be referenced using this pointer. The
  471. * callback function can access the memory via the "data" field in the
  472. * crypto_async_request data structure provided to the callback function.
  473. *
  474. * This function allows setting the callback function that is triggered once the
  475. * cipher operation completes.
  476. *
  477. * The callback function is registered with the skcipher_request handle and
  478. * must comply with the following template
  479. *
  480. * void callback_function(struct crypto_async_request *req, int error)
  481. */
  482. static inline void skcipher_request_set_callback(struct skcipher_request *req,
  483. u32 flags,
  484. crypto_completion_t compl,
  485. void *data)
  486. {
  487. req->base.complete = compl;
  488. req->base.data = data;
  489. req->base.flags = flags;
  490. }
  491. /**
  492. * skcipher_request_set_crypt() - set data buffers
  493. * @req: request handle
  494. * @src: source scatter / gather list
  495. * @dst: destination scatter / gather list
  496. * @cryptlen: number of bytes to process from @src
  497. * @iv: IV for the cipher operation which must comply with the IV size defined
  498. * by crypto_skcipher_ivsize
  499. *
  500. * This function allows setting of the source data and destination data
  501. * scatter / gather lists.
  502. *
  503. * For encryption, the source is treated as the plaintext and the
  504. * destination is the ciphertext. For a decryption operation, the use is
  505. * reversed - the source is the ciphertext and the destination is the plaintext.
  506. */
  507. static inline void skcipher_request_set_crypt(
  508. struct skcipher_request *req,
  509. struct scatterlist *src, struct scatterlist *dst,
  510. unsigned int cryptlen, void *iv)
  511. {
  512. req->src = src;
  513. req->dst = dst;
  514. req->cryptlen = cryptlen;
  515. req->iv = iv;
  516. }
  517. #endif /* _CRYPTO_SKCIPHER_H */