1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 /* 3 * Symmetric key ciphers. 4 * 5 * Copyright (c) 2007-2015 Herbert Xu <herbert@gondor.apana.org.au> 6 */ 7 8 #ifndef _CRYPTO_SKCIPHER_H 9 #define _CRYPTO_SKCIPHER_H 10 11 #include <linux/crypto.h> 12 #include <linux/kernel.h> 13 #include <linux/slab.h> 14 15 /** 16 * struct skcipher_request - Symmetric key cipher request 17 * @cryptlen: Number of bytes to encrypt or decrypt 18 * @iv: Initialisation Vector 19 * @src: Source SG list 20 * @dst: Destination SG list 21 * @base: Underlying async request 22 * @__ctx: Start of private context data 23 */ 24 struct skcipher_request { 25 unsigned int cryptlen; 26 27 u8 *iv; 28 29 struct scatterlist *src; 30 struct scatterlist *dst; 31 32 struct crypto_async_request base; 33 34 void *__ctx[] CRYPTO_MINALIGN_ATTR; 35 }; 36 37 struct crypto_skcipher { 38 unsigned int reqsize; 39 40 struct crypto_tfm base; 41 }; 42 43 struct crypto_sync_skcipher { 44 struct crypto_skcipher base; 45 }; 46 47 /** 48 * struct skcipher_alg - symmetric key cipher definition 49 * @min_keysize: Minimum key size supported by the transformation. This is the 50 * smallest key length supported by this transformation algorithm. 51 * This must be set to one of the pre-defined values as this is 52 * not hardware specific. Possible values for this field can be 53 * found via git grep "_MIN_KEY_SIZE" include/crypto/ 54 * @max_keysize: Maximum key size supported by the transformation. This is the 55 * largest key length supported by this transformation algorithm. 56 * This must be set to one of the pre-defined values as this is 57 * not hardware specific. Possible values for this field can be 58 * found via git grep "_MAX_KEY_SIZE" include/crypto/ 59 * @setkey: Set key for the transformation. This function is used to either 60 * program a supplied key into the hardware or store the key in the 61 * transformation context for programming it later. Note that this 62 * function does modify the transformation context. This function can 63 * be called multiple times during the existence of the transformation 64 * object, so one must make sure the key is properly reprogrammed into 65 * the hardware. This function is also responsible for checking the key 66 * length for validity. In case a software fallback was put in place in 67 * the @cra_init call, this function might need to use the fallback if 68 * the algorithm doesn't support all of the key sizes. 69 * @encrypt: Encrypt a scatterlist of blocks. This function is used to encrypt 70 * the supplied scatterlist containing the blocks of data. The crypto 71 * API consumer is responsible for aligning the entries of the 72 * scatterlist properly and making sure the chunks are correctly 73 * sized. In case a software fallback was put in place in the 74 * @cra_init call, this function might need to use the fallback if 75 * the algorithm doesn't support all of the key sizes. In case the 76 * key was stored in transformation context, the key might need to be 77 * re-programmed into the hardware in this function. This function 78 * shall not modify the transformation context, as this function may 79 * be called in parallel with the same transformation object. 80 * @decrypt: Decrypt a single block. This is a reverse counterpart to @encrypt 81 * and the conditions are exactly the same. 82 * @init: Initialize the cryptographic transformation object. This function 83 * is used to initialize the cryptographic transformation object. 84 * This function is called only once at the instantiation time, right 85 * after the transformation context was allocated. In case the 86 * cryptographic hardware has some special requirements which need to 87 * be handled by software, this function shall check for the precise 88 * requirement of the transformation and put any software fallbacks 89 * in place. 90 * @exit: Deinitialize the cryptographic transformation object. This is a 91 * counterpart to @init, used to remove various changes set in 92 * @init. 93 * @ivsize: IV size applicable for transformation. The consumer must provide an 94 * IV of exactly that size to perform the encrypt or decrypt operation. 95 * @chunksize: Equal to the block size except for stream ciphers such as 96 * CTR where it is set to the underlying block size. 97 * @walksize: Equal to the chunk size except in cases where the algorithm is 98 * considerably more efficient if it can operate on multiple chunks 99 * in parallel. Should be a multiple of chunksize. 100 * @base: Definition of a generic crypto algorithm. 101 * 102 * All fields except @ivsize are mandatory and must be filled. 103 */ 104 struct skcipher_alg { 105 int (*setkey)(struct crypto_skcipher *tfm, const u8 *key, 106 unsigned int keylen); 107 int (*encrypt)(struct skcipher_request *req); 108 int (*decrypt)(struct skcipher_request *req); 109 int (*init)(struct crypto_skcipher *tfm); 110 void (*exit)(struct crypto_skcipher *tfm); 111 112 unsigned int min_keysize; 113 unsigned int max_keysize; 114 unsigned int ivsize; 115 unsigned int chunksize; 116 unsigned int walksize; 117 118 struct crypto_alg base; 119 }; 120 121 #define MAX_SYNC_SKCIPHER_REQSIZE 384 122 /* 123 * This performs a type-check against the "tfm" argument to make sure 124 * all users have the correct skcipher tfm for doing on-stack requests. 125 */ 126 #define SYNC_SKCIPHER_REQUEST_ON_STACK(name, tfm) \ 127 char __##name##_desc[sizeof(struct skcipher_request) + \ 128 MAX_SYNC_SKCIPHER_REQSIZE + \ 129 (!(sizeof((struct crypto_sync_skcipher *)1 == \ 130 (typeof(tfm))1))) \ 131 ] CRYPTO_MINALIGN_ATTR; \ 132 struct skcipher_request *name = (void *)__##name##_desc 133 134 /** 135 * DOC: Symmetric Key Cipher API 136 * 137 * Symmetric key cipher API is used with the ciphers of type 138 * CRYPTO_ALG_TYPE_SKCIPHER (listed as type "skcipher" in /proc/crypto). 139 * 140 * Asynchronous cipher operations imply that the function invocation for a 141 * cipher request returns immediately before the completion of the operation. 142 * The cipher request is scheduled as a separate kernel thread and therefore 143 * load-balanced on the different CPUs via the process scheduler. To allow 144 * the kernel crypto API to inform the caller about the completion of a cipher 145 * request, the caller must provide a callback function. That function is 146 * invoked with the cipher handle when the request completes. 147 * 148 * To support the asynchronous operation, additional information than just the 149 * cipher handle must be supplied to the kernel crypto API. That additional 150 * information is given by filling in the skcipher_request data structure. 151 * 152 * For the symmetric key cipher API, the state is maintained with the tfm 153 * cipher handle. A single tfm can be used across multiple calls and in 154 * parallel. For asynchronous block cipher calls, context data supplied and 155 * only used by the caller can be referenced the request data structure in 156 * addition to the IV used for the cipher request. The maintenance of such 157 * state information would be important for a crypto driver implementer to 158 * have, because when calling the callback function upon completion of the 159 * cipher operation, that callback function may need some information about 160 * which operation just finished if it invoked multiple in parallel. This 161 * state information is unused by the kernel crypto API. 162 */ 163 164 static inline struct crypto_skcipher *__crypto_skcipher_cast( 165 struct crypto_tfm *tfm) 166 { 167 return container_of(tfm, struct crypto_skcipher, base); 168 } 169 170 /** 171 * crypto_alloc_skcipher() - allocate symmetric key cipher handle 172 * @alg_name: is the cra_name / name or cra_driver_name / driver name of the 173 * skcipher cipher 174 * @type: specifies the type of the cipher 175 * @mask: specifies the mask for the cipher 176 * 177 * Allocate a cipher handle for an skcipher. The returned struct 178 * crypto_skcipher is the cipher handle that is required for any subsequent 179 * API invocation for that skcipher. 180 * 181 * Return: allocated cipher handle in case of success; IS_ERR() is true in case 182 * of an error, PTR_ERR() returns the error code. 183 */ 184 struct crypto_skcipher *crypto_alloc_skcipher(const char *alg_name, 185 u32 type, u32 mask); 186 187 struct crypto_sync_skcipher *crypto_alloc_sync_skcipher(const char *alg_name, 188 u32 type, u32 mask); 189 190 static inline struct crypto_tfm *crypto_skcipher_tfm( 191 struct crypto_skcipher *tfm) 192 { 193 return &tfm->base; 194 } 195 196 /** 197 * crypto_free_skcipher() - zeroize and free cipher handle 198 * @tfm: cipher handle to be freed 199 */ 200 static inline void crypto_free_skcipher(struct crypto_skcipher *tfm) 201 { 202 crypto_destroy_tfm(tfm, crypto_skcipher_tfm(tfm)); 203 } 204 205 static inline void crypto_free_sync_skcipher(struct crypto_sync_skcipher *tfm) 206 { 207 crypto_free_skcipher(&tfm->base); 208 } 209 210 /** 211 * crypto_has_skcipher() - Search for the availability of an skcipher. 212 * @alg_name: is the cra_name / name or cra_driver_name / driver name of the 213 * skcipher 214 * @type: specifies the type of the skcipher 215 * @mask: specifies the mask for the skcipher 216 * 217 * Return: true when the skcipher is known to the kernel crypto API; false 218 * otherwise 219 */ 220 int crypto_has_skcipher(const char *alg_name, u32 type, u32 mask); 221 222 static inline const char *crypto_skcipher_driver_name( 223 struct crypto_skcipher *tfm) 224 { 225 return crypto_tfm_alg_driver_name(crypto_skcipher_tfm(tfm)); 226 } 227 228 static inline struct skcipher_alg *crypto_skcipher_alg( 229 struct crypto_skcipher *tfm) 230 { 231 return container_of(crypto_skcipher_tfm(tfm)->__crt_alg, 232 struct skcipher_alg, base); 233 } 234 235 static inline unsigned int crypto_skcipher_alg_ivsize(struct skcipher_alg *alg) 236 { 237 return alg->ivsize; 238 } 239 240 /** 241 * crypto_skcipher_ivsize() - obtain IV size 242 * @tfm: cipher handle 243 * 244 * The size of the IV for the skcipher referenced by the cipher handle is 245 * returned. This IV size may be zero if the cipher does not need an IV. 246 * 247 * Return: IV size in bytes 248 */ 249 static inline unsigned int crypto_skcipher_ivsize(struct crypto_skcipher *tfm) 250 { 251 return crypto_skcipher_alg(tfm)->ivsize; 252 } 253 254 static inline unsigned int crypto_sync_skcipher_ivsize( 255 struct crypto_sync_skcipher *tfm) 256 { 257 return crypto_skcipher_ivsize(&tfm->base); 258 } 259 260 /** 261 * crypto_skcipher_blocksize() - obtain block size of cipher 262 * @tfm: cipher handle 263 * 264 * The block size for the skcipher referenced with the cipher handle is 265 * returned. The caller may use that information to allocate appropriate 266 * memory for the data returned by the encryption or decryption operation 267 * 268 * Return: block size of cipher 269 */ 270 static inline unsigned int crypto_skcipher_blocksize( 271 struct crypto_skcipher *tfm) 272 { 273 return crypto_tfm_alg_blocksize(crypto_skcipher_tfm(tfm)); 274 } 275 276 static inline unsigned int crypto_skcipher_alg_chunksize( 277 struct skcipher_alg *alg) 278 { 279 return alg->chunksize; 280 } 281 282 /** 283 * crypto_skcipher_chunksize() - obtain chunk size 284 * @tfm: cipher handle 285 * 286 * The block size is set to one for ciphers such as CTR. However, 287 * you still need to provide incremental updates in multiples of 288 * the underlying block size as the IV does not have sub-block 289 * granularity. This is known in this API as the chunk size. 290 * 291 * Return: chunk size in bytes 292 */ 293 static inline unsigned int crypto_skcipher_chunksize( 294 struct crypto_skcipher *tfm) 295 { 296 return crypto_skcipher_alg_chunksize(crypto_skcipher_alg(tfm)); 297 } 298 299 static inline unsigned int crypto_sync_skcipher_blocksize( 300 struct crypto_sync_skcipher *tfm) 301 { 302 return crypto_skcipher_blocksize(&tfm->base); 303 } 304 305 static inline unsigned int crypto_skcipher_alignmask( 306 struct crypto_skcipher *tfm) 307 { 308 return crypto_tfm_alg_alignmask(crypto_skcipher_tfm(tfm)); 309 } 310 311 static inline u32 crypto_skcipher_get_flags(struct crypto_skcipher *tfm) 312 { 313 return crypto_tfm_get_flags(crypto_skcipher_tfm(tfm)); 314 } 315 316 static inline void crypto_skcipher_set_flags(struct crypto_skcipher *tfm, 317 u32 flags) 318 { 319 crypto_tfm_set_flags(crypto_skcipher_tfm(tfm), flags); 320 } 321 322 static inline void crypto_skcipher_clear_flags(struct crypto_skcipher *tfm, 323 u32 flags) 324 { 325 crypto_tfm_clear_flags(crypto_skcipher_tfm(tfm), flags); 326 } 327 328 static inline u32 crypto_sync_skcipher_get_flags( 329 struct crypto_sync_skcipher *tfm) 330 { 331 return crypto_skcipher_get_flags(&tfm->base); 332 } 333 334 static inline void crypto_sync_skcipher_set_flags( 335 struct crypto_sync_skcipher *tfm, u32 flags) 336 { 337 crypto_skcipher_set_flags(&tfm->base, flags); 338 } 339 340 static inline void crypto_sync_skcipher_clear_flags( 341 struct crypto_sync_skcipher *tfm, u32 flags) 342 { 343 crypto_skcipher_clear_flags(&tfm->base, flags); 344 } 345 346 /** 347 * crypto_skcipher_setkey() - set key for cipher 348 * @tfm: cipher handle 349 * @key: buffer holding the key 350 * @keylen: length of the key in bytes 351 * 352 * The caller provided key is set for the skcipher referenced by the cipher 353 * handle. 354 * 355 * Note, the key length determines the cipher type. Many block ciphers implement 356 * different cipher modes depending on the key size, such as AES-128 vs AES-192 357 * vs. AES-256. When providing a 16 byte key for an AES cipher handle, AES-128 358 * is performed. 359 * 360 * Return: 0 if the setting of the key was successful; < 0 if an error occurred 361 */ 362 int crypto_skcipher_setkey(struct crypto_skcipher *tfm, 363 const u8 *key, unsigned int keylen); 364 365 static inline int crypto_sync_skcipher_setkey(struct crypto_sync_skcipher *tfm, 366 const u8 *key, unsigned int keylen) 367 { 368 return crypto_skcipher_setkey(&tfm->base, key, keylen); 369 } 370 371 static inline unsigned int crypto_skcipher_min_keysize( 372 struct crypto_skcipher *tfm) 373 { 374 return crypto_skcipher_alg(tfm)->min_keysize; 375 } 376 377 static inline unsigned int crypto_skcipher_max_keysize( 378 struct crypto_skcipher *tfm) 379 { 380 return crypto_skcipher_alg(tfm)->max_keysize; 381 } 382 383 /** 384 * crypto_skcipher_reqtfm() - obtain cipher handle from request 385 * @req: skcipher_request out of which the cipher handle is to be obtained 386 * 387 * Return the crypto_skcipher handle when furnishing an skcipher_request 388 * data structure. 389 * 390 * Return: crypto_skcipher handle 391 */ 392 static inline struct crypto_skcipher *crypto_skcipher_reqtfm( 393 struct skcipher_request *req) 394 { 395 return __crypto_skcipher_cast(req->base.tfm); 396 } 397 398 static inline struct crypto_sync_skcipher *crypto_sync_skcipher_reqtfm( 399 struct skcipher_request *req) 400 { 401 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); 402 403 return container_of(tfm, struct crypto_sync_skcipher, base); 404 } 405 406 /** 407 * crypto_skcipher_encrypt() - encrypt plaintext 408 * @req: reference to the skcipher_request handle that holds all information 409 * needed to perform the cipher operation 410 * 411 * Encrypt plaintext data using the skcipher_request handle. That data 412 * structure and how it is filled with data is discussed with the 413 * skcipher_request_* functions. 414 * 415 * Return: 0 if the cipher operation was successful; < 0 if an error occurred 416 */ 417 int crypto_skcipher_encrypt(struct skcipher_request *req); 418 419 /** 420 * crypto_skcipher_decrypt() - decrypt ciphertext 421 * @req: reference to the skcipher_request handle that holds all information 422 * needed to perform the cipher operation 423 * 424 * Decrypt ciphertext data using the skcipher_request handle. That data 425 * structure and how it is filled with data is discussed with the 426 * skcipher_request_* functions. 427 * 428 * Return: 0 if the cipher operation was successful; < 0 if an error occurred 429 */ 430 int crypto_skcipher_decrypt(struct skcipher_request *req); 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 void skcipher_request_set_sync_tfm(struct skcipher_request *req, 469 struct crypto_sync_skcipher *tfm) 470 { 471 skcipher_request_set_tfm(req, &tfm->base); 472 } 473 474 static inline struct skcipher_request *skcipher_request_cast( 475 struct crypto_async_request *req) 476 { 477 return container_of(req, struct skcipher_request, base); 478 } 479 480 /** 481 * skcipher_request_alloc() - allocate request data structure 482 * @tfm: cipher handle to be registered with the request 483 * @gfp: memory allocation flag that is handed to kmalloc by the API call. 484 * 485 * Allocate the request data structure that must be used with the skcipher 486 * encrypt and decrypt API calls. During the allocation, the provided skcipher 487 * handle is registered in the request data structure. 488 * 489 * Return: allocated request handle in case of success, or NULL if out of memory 490 */ 491 static inline struct skcipher_request *skcipher_request_alloc( 492 struct crypto_skcipher *tfm, gfp_t gfp) 493 { 494 struct skcipher_request *req; 495 496 req = kmalloc(sizeof(struct skcipher_request) + 497 crypto_skcipher_reqsize(tfm), gfp); 498 499 if (likely(req)) 500 skcipher_request_set_tfm(req, tfm); 501 502 return req; 503 } 504 505 /** 506 * skcipher_request_free() - zeroize and free request data structure 507 * @req: request data structure cipher handle to be freed 508 */ 509 static inline void skcipher_request_free(struct skcipher_request *req) 510 { 511 kfree_sensitive(req); 512 } 513 514 static inline void skcipher_request_zero(struct skcipher_request *req) 515 { 516 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); 517 518 memzero_explicit(req, sizeof(*req) + crypto_skcipher_reqsize(tfm)); 519 } 520 521 /** 522 * skcipher_request_set_callback() - set asynchronous callback function 523 * @req: request handle 524 * @flags: specify zero or an ORing of the flags 525 * CRYPTO_TFM_REQ_MAY_BACKLOG the request queue may back log and 526 * increase the wait queue beyond the initial maximum size; 527 * CRYPTO_TFM_REQ_MAY_SLEEP the request processing may sleep 528 * @compl: callback function pointer to be registered with the request handle 529 * @data: The data pointer refers to memory that is not used by the kernel 530 * crypto API, but provided to the callback function for it to use. Here, 531 * the caller can provide a reference to memory the callback function can 532 * operate on. As the callback function is invoked asynchronously to the 533 * related functionality, it may need to access data structures of the 534 * related functionality which can be referenced using this pointer. The 535 * callback function can access the memory via the "data" field in the 536 * crypto_async_request data structure provided to the callback function. 537 * 538 * This function allows setting the callback function that is triggered once the 539 * cipher operation completes. 540 * 541 * The callback function is registered with the skcipher_request handle and 542 * must comply with the following template:: 543 * 544 * void callback_function(struct crypto_async_request *req, int error) 545 */ 546 static inline void skcipher_request_set_callback(struct skcipher_request *req, 547 u32 flags, 548 crypto_completion_t compl, 549 void *data) 550 { 551 req->base.complete = compl; 552 req->base.data = data; 553 req->base.flags = flags; 554 } 555 556 /** 557 * skcipher_request_set_crypt() - set data buffers 558 * @req: request handle 559 * @src: source scatter / gather list 560 * @dst: destination scatter / gather list 561 * @cryptlen: number of bytes to process from @src 562 * @iv: IV for the cipher operation which must comply with the IV size defined 563 * by crypto_skcipher_ivsize 564 * 565 * This function allows setting of the source data and destination data 566 * scatter / gather lists. 567 * 568 * For encryption, the source is treated as the plaintext and the 569 * destination is the ciphertext. For a decryption operation, the use is 570 * reversed - the source is the ciphertext and the destination is the plaintext. 571 */ 572 static inline void skcipher_request_set_crypt( 573 struct skcipher_request *req, 574 struct scatterlist *src, struct scatterlist *dst, 575 unsigned int cryptlen, void *iv) 576 { 577 req->src = src; 578 req->dst = dst; 579 req->cryptlen = cryptlen; 580 req->iv = iv; 581 } 582 583 #endif /* _CRYPTO_SKCIPHER_H */ 584 585