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 13 #ifndef _CRYPTO_SKCIPHER_H 14 #define _CRYPTO_SKCIPHER_H 15 16 #include <linux/crypto.h> 17 #include <linux/kernel.h> 18 #include <linux/slab.h> 19 20 /** 21 * struct skcipher_request - Symmetric key cipher request 22 * @cryptlen: Number of bytes to encrypt or decrypt 23 * @iv: Initialisation Vector 24 * @src: Source SG list 25 * @dst: Destination SG list 26 * @base: Underlying async request request 27 * @__ctx: Start of private context data 28 */ 29 struct skcipher_request { 30 unsigned int cryptlen; 31 32 u8 *iv; 33 34 struct scatterlist *src; 35 struct scatterlist *dst; 36 37 struct crypto_async_request base; 38 39 void *__ctx[] CRYPTO_MINALIGN_ATTR; 40 }; 41 42 /** 43 * struct skcipher_givcrypt_request - Crypto request with IV generation 44 * @seq: Sequence number for IV generation 45 * @giv: Space for generated IV 46 * @creq: The crypto request itself 47 */ 48 struct skcipher_givcrypt_request { 49 u64 seq; 50 u8 *giv; 51 52 struct ablkcipher_request creq; 53 }; 54 55 struct crypto_skcipher { 56 int (*setkey)(struct crypto_skcipher *tfm, const u8 *key, 57 unsigned int keylen); 58 int (*encrypt)(struct skcipher_request *req); 59 int (*decrypt)(struct skcipher_request *req); 60 61 unsigned int ivsize; 62 unsigned int reqsize; 63 unsigned int keysize; 64 65 struct crypto_tfm base; 66 }; 67 68 /** 69 * struct skcipher_alg - symmetric key cipher definition 70 * @min_keysize: Minimum key size supported by the transformation. This is the 71 * smallest key length supported by this transformation algorithm. 72 * This must be set to one of the pre-defined values as this is 73 * not hardware specific. Possible values for this field can be 74 * found via git grep "_MIN_KEY_SIZE" include/crypto/ 75 * @max_keysize: Maximum key size supported by the transformation. This is the 76 * largest key length supported by this transformation algorithm. 77 * This must be set to one of the pre-defined values as this is 78 * not hardware specific. Possible values for this field can be 79 * found via git grep "_MAX_KEY_SIZE" include/crypto/ 80 * @setkey: Set key for the transformation. This function is used to either 81 * program a supplied key into the hardware or store the key in the 82 * transformation context for programming it later. Note that this 83 * function does modify the transformation context. This function can 84 * be called multiple times during the existence of the transformation 85 * object, so one must make sure the key is properly reprogrammed into 86 * the hardware. This function is also responsible for checking the key 87 * length for validity. In case a software fallback was put in place in 88 * the @cra_init call, this function might need to use the fallback if 89 * the algorithm doesn't support all of the key sizes. 90 * @encrypt: Encrypt a scatterlist of blocks. This function is used to encrypt 91 * the supplied scatterlist containing the blocks of data. The crypto 92 * API consumer is responsible for aligning the entries of the 93 * scatterlist properly and making sure the chunks are correctly 94 * sized. In case a software fallback was put in place in the 95 * @cra_init call, this function might need to use the fallback if 96 * the algorithm doesn't support all of the key sizes. In case the 97 * key was stored in transformation context, the key might need to be 98 * re-programmed into the hardware in this function. This function 99 * shall not modify the transformation context, as this function may 100 * be called in parallel with the same transformation object. 101 * @decrypt: Decrypt a single block. This is a reverse counterpart to @encrypt 102 * and the conditions are exactly the same. 103 * @init: Initialize the cryptographic transformation object. This function 104 * is used to initialize the cryptographic transformation object. 105 * This function is called only once at the instantiation time, right 106 * after the transformation context was allocated. In case the 107 * cryptographic hardware has some special requirements which need to 108 * be handled by software, this function shall check for the precise 109 * requirement of the transformation and put any software fallbacks 110 * in place. 111 * @exit: Deinitialize the cryptographic transformation object. This is a 112 * counterpart to @init, used to remove various changes set in 113 * @init. 114 * @ivsize: IV size applicable for transformation. The consumer must provide an 115 * IV of exactly that size to perform the encrypt or decrypt operation. 116 * @chunksize: Equal to the block size except for stream ciphers such as 117 * CTR where it is set to the underlying block size. 118 * @base: Definition of a generic crypto algorithm. 119 * 120 * All fields except @ivsize are mandatory and must be filled. 121 */ 122 struct skcipher_alg { 123 int (*setkey)(struct crypto_skcipher *tfm, const u8 *key, 124 unsigned int keylen); 125 int (*encrypt)(struct skcipher_request *req); 126 int (*decrypt)(struct skcipher_request *req); 127 int (*init)(struct crypto_skcipher *tfm); 128 void (*exit)(struct crypto_skcipher *tfm); 129 130 unsigned int min_keysize; 131 unsigned int max_keysize; 132 unsigned int ivsize; 133 unsigned int chunksize; 134 135 struct crypto_alg base; 136 }; 137 138 #define SKCIPHER_REQUEST_ON_STACK(name, tfm) \ 139 char __##name##_desc[sizeof(struct skcipher_request) + \ 140 crypto_skcipher_reqsize(tfm)] CRYPTO_MINALIGN_ATTR; \ 141 struct skcipher_request *name = (void *)__##name##_desc 142 143 /** 144 * DOC: Symmetric Key Cipher API 145 * 146 * Symmetric key cipher API is used with the ciphers of type 147 * CRYPTO_ALG_TYPE_SKCIPHER (listed as type "skcipher" in /proc/crypto). 148 * 149 * Asynchronous cipher operations imply that the function invocation for a 150 * cipher request returns immediately before the completion of the operation. 151 * The cipher request is scheduled as a separate kernel thread and therefore 152 * load-balanced on the different CPUs via the process scheduler. To allow 153 * the kernel crypto API to inform the caller about the completion of a cipher 154 * request, the caller must provide a callback function. That function is 155 * invoked with the cipher handle when the request completes. 156 * 157 * To support the asynchronous operation, additional information than just the 158 * cipher handle must be supplied to the kernel crypto API. That additional 159 * information is given by filling in the skcipher_request data structure. 160 * 161 * For the symmetric key cipher API, the state is maintained with the tfm 162 * cipher handle. A single tfm can be used across multiple calls and in 163 * parallel. For asynchronous block cipher calls, context data supplied and 164 * only used by the caller can be referenced the request data structure in 165 * addition to the IV used for the cipher request. The maintenance of such 166 * state information would be important for a crypto driver implementer to 167 * have, because when calling the callback function upon completion of the 168 * cipher operation, that callback function may need some information about 169 * which operation just finished if it invoked multiple in parallel. This 170 * state information is unused by the kernel crypto API. 171 */ 172 173 static inline struct crypto_skcipher *__crypto_skcipher_cast( 174 struct crypto_tfm *tfm) 175 { 176 return container_of(tfm, struct crypto_skcipher, base); 177 } 178 179 /** 180 * crypto_alloc_skcipher() - allocate symmetric key cipher handle 181 * @alg_name: is the cra_name / name or cra_driver_name / driver name of the 182 * skcipher cipher 183 * @type: specifies the type of the cipher 184 * @mask: specifies the mask for the cipher 185 * 186 * Allocate a cipher handle for an skcipher. The returned struct 187 * crypto_skcipher is the cipher handle that is required for any subsequent 188 * API invocation for that skcipher. 189 * 190 * Return: allocated cipher handle in case of success; IS_ERR() is true in case 191 * of an error, PTR_ERR() returns the error code. 192 */ 193 struct crypto_skcipher *crypto_alloc_skcipher(const char *alg_name, 194 u32 type, u32 mask); 195 196 static inline struct crypto_tfm *crypto_skcipher_tfm( 197 struct crypto_skcipher *tfm) 198 { 199 return &tfm->base; 200 } 201 202 /** 203 * crypto_free_skcipher() - zeroize and free cipher handle 204 * @tfm: cipher handle to be freed 205 */ 206 static inline void crypto_free_skcipher(struct crypto_skcipher *tfm) 207 { 208 crypto_destroy_tfm(tfm, crypto_skcipher_tfm(tfm)); 209 } 210 211 /** 212 * crypto_has_skcipher() - Search for the availability of an skcipher. 213 * @alg_name: is the cra_name / name or cra_driver_name / driver name of the 214 * skcipher 215 * @type: specifies the type of the cipher 216 * @mask: specifies the mask for the cipher 217 * 218 * Return: true when the skcipher is known to the kernel crypto API; false 219 * otherwise 220 */ 221 static inline int crypto_has_skcipher(const char *alg_name, u32 type, 222 u32 mask) 223 { 224 return crypto_has_alg(alg_name, crypto_skcipher_type(type), 225 crypto_skcipher_mask(mask)); 226 } 227 228 /** 229 * crypto_has_skcipher2() - Search for the availability of an skcipher. 230 * @alg_name: is the cra_name / name or cra_driver_name / driver name of the 231 * skcipher 232 * @type: specifies the type of the skcipher 233 * @mask: specifies the mask for the skcipher 234 * 235 * Return: true when the skcipher is known to the kernel crypto API; false 236 * otherwise 237 */ 238 int crypto_has_skcipher2(const char *alg_name, u32 type, u32 mask); 239 240 static inline const char *crypto_skcipher_driver_name( 241 struct crypto_skcipher *tfm) 242 { 243 return crypto_tfm_alg_driver_name(crypto_skcipher_tfm(tfm)); 244 } 245 246 static inline struct skcipher_alg *crypto_skcipher_alg( 247 struct crypto_skcipher *tfm) 248 { 249 return container_of(crypto_skcipher_tfm(tfm)->__crt_alg, 250 struct skcipher_alg, base); 251 } 252 253 static inline unsigned int crypto_skcipher_alg_ivsize(struct skcipher_alg *alg) 254 { 255 if ((alg->base.cra_flags & CRYPTO_ALG_TYPE_MASK) == 256 CRYPTO_ALG_TYPE_BLKCIPHER) 257 return alg->base.cra_blkcipher.ivsize; 258 259 if (alg->base.cra_ablkcipher.encrypt) 260 return alg->base.cra_ablkcipher.ivsize; 261 262 return alg->ivsize; 263 } 264 265 /** 266 * crypto_skcipher_ivsize() - obtain IV size 267 * @tfm: cipher handle 268 * 269 * The size of the IV for the skcipher referenced by the cipher handle is 270 * returned. This IV size may be zero if the cipher does not need an IV. 271 * 272 * Return: IV size in bytes 273 */ 274 static inline unsigned int crypto_skcipher_ivsize(struct crypto_skcipher *tfm) 275 { 276 return tfm->ivsize; 277 } 278 279 static inline unsigned int crypto_skcipher_alg_chunksize( 280 struct skcipher_alg *alg) 281 { 282 if ((alg->base.cra_flags & CRYPTO_ALG_TYPE_MASK) == 283 CRYPTO_ALG_TYPE_BLKCIPHER) 284 return alg->base.cra_blocksize; 285 286 if (alg->base.cra_ablkcipher.encrypt) 287 return alg->base.cra_blocksize; 288 289 return alg->chunksize; 290 } 291 292 /** 293 * crypto_skcipher_chunksize() - obtain chunk size 294 * @tfm: cipher handle 295 * 296 * The block size is set to one for ciphers such as CTR. However, 297 * you still need to provide incremental updates in multiples of 298 * the underlying block size as the IV does not have sub-block 299 * granularity. This is known in this API as the chunk size. 300 * 301 * Return: chunk size in bytes 302 */ 303 static inline unsigned int crypto_skcipher_chunksize( 304 struct crypto_skcipher *tfm) 305 { 306 return crypto_skcipher_alg_chunksize(crypto_skcipher_alg(tfm)); 307 } 308 309 /** 310 * crypto_skcipher_blocksize() - obtain block size of cipher 311 * @tfm: cipher handle 312 * 313 * The block size for the skcipher referenced with the cipher handle is 314 * returned. The caller may use that information to allocate appropriate 315 * memory for the data returned by the encryption or decryption operation 316 * 317 * Return: block size of cipher 318 */ 319 static inline unsigned int crypto_skcipher_blocksize( 320 struct crypto_skcipher *tfm) 321 { 322 return crypto_tfm_alg_blocksize(crypto_skcipher_tfm(tfm)); 323 } 324 325 static inline unsigned int crypto_skcipher_alignmask( 326 struct crypto_skcipher *tfm) 327 { 328 return crypto_tfm_alg_alignmask(crypto_skcipher_tfm(tfm)); 329 } 330 331 static inline u32 crypto_skcipher_get_flags(struct crypto_skcipher *tfm) 332 { 333 return crypto_tfm_get_flags(crypto_skcipher_tfm(tfm)); 334 } 335 336 static inline void crypto_skcipher_set_flags(struct crypto_skcipher *tfm, 337 u32 flags) 338 { 339 crypto_tfm_set_flags(crypto_skcipher_tfm(tfm), flags); 340 } 341 342 static inline void crypto_skcipher_clear_flags(struct crypto_skcipher *tfm, 343 u32 flags) 344 { 345 crypto_tfm_clear_flags(crypto_skcipher_tfm(tfm), flags); 346 } 347 348 /** 349 * crypto_skcipher_setkey() - set key for cipher 350 * @tfm: cipher handle 351 * @key: buffer holding the key 352 * @keylen: length of the key in bytes 353 * 354 * The caller provided key is set for the skcipher referenced by the cipher 355 * handle. 356 * 357 * Note, the key length determines the cipher type. Many block ciphers implement 358 * different cipher modes depending on the key size, such as AES-128 vs AES-192 359 * vs. AES-256. When providing a 16 byte key for an AES cipher handle, AES-128 360 * is performed. 361 * 362 * Return: 0 if the setting of the key was successful; < 0 if an error occurred 363 */ 364 static inline int crypto_skcipher_setkey(struct crypto_skcipher *tfm, 365 const u8 *key, unsigned int keylen) 366 { 367 return tfm->setkey(tfm, key, keylen); 368 } 369 370 static inline bool crypto_skcipher_has_setkey(struct crypto_skcipher *tfm) 371 { 372 return tfm->keysize; 373 } 374 375 static inline unsigned int crypto_skcipher_default_keysize( 376 struct crypto_skcipher *tfm) 377 { 378 return tfm->keysize; 379 } 380 381 /** 382 * crypto_skcipher_reqtfm() - obtain cipher handle from request 383 * @req: skcipher_request out of which the cipher handle is to be obtained 384 * 385 * Return the crypto_skcipher handle when furnishing an skcipher_request 386 * data structure. 387 * 388 * Return: crypto_skcipher handle 389 */ 390 static inline struct crypto_skcipher *crypto_skcipher_reqtfm( 391 struct skcipher_request *req) 392 { 393 return __crypto_skcipher_cast(req->base.tfm); 394 } 395 396 /** 397 * crypto_skcipher_encrypt() - encrypt plaintext 398 * @req: reference to the skcipher_request handle that holds all information 399 * needed to perform the cipher operation 400 * 401 * Encrypt plaintext data using the skcipher_request handle. That data 402 * structure and how it is filled with data is discussed with the 403 * skcipher_request_* functions. 404 * 405 * Return: 0 if the cipher operation was successful; < 0 if an error occurred 406 */ 407 static inline int crypto_skcipher_encrypt(struct skcipher_request *req) 408 { 409 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); 410 411 return tfm->encrypt(req); 412 } 413 414 /** 415 * crypto_skcipher_decrypt() - decrypt ciphertext 416 * @req: reference to the skcipher_request handle that holds all information 417 * needed to perform the cipher operation 418 * 419 * Decrypt ciphertext data using the skcipher_request handle. That data 420 * structure and how it is filled with data is discussed with the 421 * skcipher_request_* functions. 422 * 423 * Return: 0 if the cipher operation was successful; < 0 if an error occurred 424 */ 425 static inline int crypto_skcipher_decrypt(struct skcipher_request *req) 426 { 427 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); 428 429 return tfm->decrypt(req); 430 } 431 432 /** 433 * DOC: Symmetric Key Cipher Request Handle 434 * 435 * The skcipher_request data structure contains all pointers to data 436 * required for the symmetric key cipher operation. This includes the cipher 437 * handle (which can be used by multiple skcipher_request instances), pointer 438 * to plaintext and ciphertext, asynchronous callback function, etc. It acts 439 * as a handle to the skcipher_request_* API calls in a similar way as 440 * skcipher handle to the crypto_skcipher_* API calls. 441 */ 442 443 /** 444 * crypto_skcipher_reqsize() - obtain size of the request data structure 445 * @tfm: cipher handle 446 * 447 * Return: number of bytes 448 */ 449 static inline unsigned int crypto_skcipher_reqsize(struct crypto_skcipher *tfm) 450 { 451 return tfm->reqsize; 452 } 453 454 /** 455 * skcipher_request_set_tfm() - update cipher handle reference in request 456 * @req: request handle to be modified 457 * @tfm: cipher handle that shall be added to the request handle 458 * 459 * Allow the caller to replace the existing skcipher handle in the request 460 * data structure with a different one. 461 */ 462 static inline void skcipher_request_set_tfm(struct skcipher_request *req, 463 struct crypto_skcipher *tfm) 464 { 465 req->base.tfm = crypto_skcipher_tfm(tfm); 466 } 467 468 static inline struct skcipher_request *skcipher_request_cast( 469 struct crypto_async_request *req) 470 { 471 return container_of(req, struct skcipher_request, base); 472 } 473 474 /** 475 * skcipher_request_alloc() - allocate request data structure 476 * @tfm: cipher handle to be registered with the request 477 * @gfp: memory allocation flag that is handed to kmalloc by the API call. 478 * 479 * Allocate the request data structure that must be used with the skcipher 480 * encrypt and decrypt API calls. During the allocation, the provided skcipher 481 * handle is registered in the request data structure. 482 * 483 * Return: allocated request handle in case of success, or NULL if out of memory 484 */ 485 static inline struct skcipher_request *skcipher_request_alloc( 486 struct crypto_skcipher *tfm, gfp_t gfp) 487 { 488 struct skcipher_request *req; 489 490 req = kmalloc(sizeof(struct skcipher_request) + 491 crypto_skcipher_reqsize(tfm), gfp); 492 493 if (likely(req)) 494 skcipher_request_set_tfm(req, tfm); 495 496 return req; 497 } 498 499 /** 500 * skcipher_request_free() - zeroize and free request data structure 501 * @req: request data structure cipher handle to be freed 502 */ 503 static inline void skcipher_request_free(struct skcipher_request *req) 504 { 505 kzfree(req); 506 } 507 508 static inline void skcipher_request_zero(struct skcipher_request *req) 509 { 510 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); 511 512 memzero_explicit(req, sizeof(*req) + crypto_skcipher_reqsize(tfm)); 513 } 514 515 /** 516 * skcipher_request_set_callback() - set asynchronous callback function 517 * @req: request handle 518 * @flags: specify zero or an ORing of the flags 519 * CRYPTO_TFM_REQ_MAY_BACKLOG the request queue may back log and 520 * increase the wait queue beyond the initial maximum size; 521 * CRYPTO_TFM_REQ_MAY_SLEEP the request processing may sleep 522 * @compl: callback function pointer to be registered with the request handle 523 * @data: The data pointer refers to memory that is not used by the kernel 524 * crypto API, but provided to the callback function for it to use. Here, 525 * the caller can provide a reference to memory the callback function can 526 * operate on. As the callback function is invoked asynchronously to the 527 * related functionality, it may need to access data structures of the 528 * related functionality which can be referenced using this pointer. The 529 * callback function can access the memory via the "data" field in the 530 * crypto_async_request data structure provided to the callback function. 531 * 532 * This function allows setting the callback function that is triggered once the 533 * cipher operation completes. 534 * 535 * The callback function is registered with the skcipher_request handle and 536 * must comply with the following template 537 * 538 * void callback_function(struct crypto_async_request *req, int error) 539 */ 540 static inline void skcipher_request_set_callback(struct skcipher_request *req, 541 u32 flags, 542 crypto_completion_t compl, 543 void *data) 544 { 545 req->base.complete = compl; 546 req->base.data = data; 547 req->base.flags = flags; 548 } 549 550 /** 551 * skcipher_request_set_crypt() - set data buffers 552 * @req: request handle 553 * @src: source scatter / gather list 554 * @dst: destination scatter / gather list 555 * @cryptlen: number of bytes to process from @src 556 * @iv: IV for the cipher operation which must comply with the IV size defined 557 * by crypto_skcipher_ivsize 558 * 559 * This function allows setting of the source data and destination data 560 * scatter / gather lists. 561 * 562 * For encryption, the source is treated as the plaintext and the 563 * destination is the ciphertext. For a decryption operation, the use is 564 * reversed - the source is the ciphertext and the destination is the plaintext. 565 */ 566 static inline void skcipher_request_set_crypt( 567 struct skcipher_request *req, 568 struct scatterlist *src, struct scatterlist *dst, 569 unsigned int cryptlen, void *iv) 570 { 571 req->src = src; 572 req->dst = dst; 573 req->cryptlen = cryptlen; 574 req->iv = iv; 575 } 576 577 #endif /* _CRYPTO_SKCIPHER_H */ 578 579