include/crypto/skcipher.h

   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  *
 119  * All fields except @ivsize are mandatory and must be filled.
 120  */
 121 struct skcipher_alg {
 122         int (*setkey)(struct crypto_skcipher *tfm, const u8 *key,
 123                       unsigned int keylen);
 124         int (*encrypt)(struct skcipher_request *req);
 125         int (*decrypt)(struct skcipher_request *req);
 126         int (*init)(struct crypto_skcipher *tfm);
 127         void (*exit)(struct crypto_skcipher *tfm);
 128
 129         unsigned int min_keysize;
 130         unsigned int max_keysize;
 131         unsigned int ivsize;
 132         unsigned int chunksize;
 133
 134         struct crypto_alg base;
 135 };
 136
 137 #define SKCIPHER_REQUEST_ON_STACK(name, tfm) \
 138         char __##name##_desc[sizeof(struct skcipher_request) + \
 139                 crypto_skcipher_reqsize(tfm)] CRYPTO_MINALIGN_ATTR; \
 140         struct skcipher_request *name = (void *)__##name##_desc
 141
 142 /**
 143  * DOC: Symmetric Key Cipher API
 144  *
 145  * Symmetric key cipher API is used with the ciphers of type
 146  * CRYPTO_ALG_TYPE_SKCIPHER (listed as type "skcipher" in /proc/crypto).
 147  *
 148  * Asynchronous cipher operations imply that the function invocation for a
 149  * cipher request returns immediately before the completion of the operation.
 150  * The cipher request is scheduled as a separate kernel thread and therefore
 151  * load-balanced on the different CPUs via the process scheduler. To allow
 152  * the kernel crypto API to inform the caller about the completion of a cipher
 153  * request, the caller must provide a callback function. That function is
 154  * invoked with the cipher handle when the request completes.
 155  *
 156  * To support the asynchronous operation, additional information than just the
 157  * cipher handle must be supplied to the kernel crypto API. That additional
 158  * information is given by filling in the skcipher_request data structure.
 159  *
 160  * For the symmetric key cipher API, the state is maintained with the tfm
 161  * cipher handle. A single tfm can be used across multiple calls and in
 162  * parallel. For asynchronous block cipher calls, context data supplied and
 163  * only used by the caller can be referenced the request data structure in
 164  * addition to the IV used for the cipher request. The maintenance of such
 165  * state information would be important for a crypto driver implementer to
 166  * have, because when calling the callback function upon completion of the
 167  * cipher operation, that callback function may need some information about
 168  * which operation just finished if it invoked multiple in parallel. This
 169  * state information is unused by the kernel crypto API.
 170  */
 171
 172 static inline struct crypto_skcipher *__crypto_skcipher_cast(
 173         struct crypto_tfm *tfm)
 174 {
 175         return container_of(tfm, struct crypto_skcipher, base);
 176 }
 177
 178 /**
 179  * crypto_alloc_skcipher() - allocate symmetric key cipher handle
 180  * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
 181  *            skcipher cipher
 182  * @type: specifies the type of the cipher
 183  * @mask: specifies the mask for the cipher
 184  *
 185  * Allocate a cipher handle for an skcipher. The returned struct
 186  * crypto_skcipher is the cipher handle that is required for any subsequent
 187  * API invocation for that skcipher.
 188  *
 189  * Return: allocated cipher handle in case of success; IS_ERR() is true in case
 190  *         of an error, PTR_ERR() returns the error code.
 191  */
 192 struct crypto_skcipher *crypto_alloc_skcipher(const char *alg_name,
 193                                               u32 type, u32 mask);
 194
 195 static inline struct crypto_tfm *crypto_skcipher_tfm(
 196         struct crypto_skcipher *tfm)
 197 {
 198         return &tfm->base;
 199 }
 200
 201 /**
 202  * crypto_free_skcipher() - zeroize and free cipher handle
 203  * @tfm: cipher handle to be freed
 204  */
 205 static inline void crypto_free_skcipher(struct crypto_skcipher *tfm)
 206 {
 207         crypto_destroy_tfm(tfm, crypto_skcipher_tfm(tfm));
 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 cipher
 215  * @mask: specifies the mask for the cipher
 216  *
 217  * Return: true when the skcipher is known to the kernel crypto API; false
 218  *         otherwise
 219  */
 220 static inline int crypto_has_skcipher(const char *alg_name, u32 type,
 221                                         u32 mask)
 222 {
 223         return crypto_has_alg(alg_name, crypto_skcipher_type(type),
 224                               crypto_skcipher_mask(mask));
 225 }
 226
 227 /**
 228  * crypto_has_skcipher2() - Search for the availability of an skcipher.
 229  * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
 230  *            skcipher
 231  * @type: specifies the type of the skcipher
 232  * @mask: specifies the mask for the skcipher
 233  *
 234  * Return: true when the skcipher is known to the kernel crypto API; false
 235  *         otherwise
 236  */
 237 int crypto_has_skcipher2(const char *alg_name, u32 type, u32 mask);
 238
 239 static inline const char *crypto_skcipher_driver_name(
 240         struct crypto_skcipher *tfm)
 241 {
 242         return crypto_tfm_alg_driver_name(crypto_skcipher_tfm(tfm));
 243 }
 244
 245 static inline struct skcipher_alg *crypto_skcipher_alg(
 246         struct crypto_skcipher *tfm)
 247 {
 248         return container_of(crypto_skcipher_tfm(tfm)->__crt_alg,
 249                             struct skcipher_alg, base);
 250 }
 251
 252 static inline unsigned int crypto_skcipher_alg_ivsize(struct skcipher_alg *alg)
 253 {
 254         if ((alg->base.cra_flags & CRYPTO_ALG_TYPE_MASK) ==
 255             CRYPTO_ALG_TYPE_BLKCIPHER)
 256                 return alg->base.cra_blkcipher.ivsize;
 257
 258         if (alg->base.cra_ablkcipher.encrypt)
 259                 return alg->base.cra_ablkcipher.ivsize;
 260
 261         return alg->ivsize;
 262 }
 263
 264 /**
 265  * crypto_skcipher_ivsize() - obtain IV size
 266  * @tfm: cipher handle
 267  *
 268  * The size of the IV for the skcipher referenced by the cipher handle is
 269  * returned. This IV size may be zero if the cipher does not need an IV.
 270  *
 271  * Return: IV size in bytes
 272  */
 273 static inline unsigned int crypto_skcipher_ivsize(struct crypto_skcipher *tfm)
 274 {
 275         return tfm->ivsize;
 276 }
 277
 278 static inline unsigned int crypto_skcipher_alg_chunksize(
 279         struct skcipher_alg *alg)
 280 {
 281         if ((alg->base.cra_flags & CRYPTO_ALG_TYPE_MASK) ==
 282             CRYPTO_ALG_TYPE_BLKCIPHER)
 283                 return alg->base.cra_blocksize;
 284
 285         if (alg->base.cra_ablkcipher.encrypt)
 286                 return alg->base.cra_blocksize;
 287
 288         return alg->chunksize;
 289 }
 290
 291 /**
 292  * crypto_skcipher_chunksize() - obtain chunk size
 293  * @tfm: cipher handle
 294  *
 295  * The block size is set to one for ciphers such as CTR.  However,
 296  * you still need to provide incremental updates in multiples of
 297  * the underlying block size as the IV does not have sub-block
 298  * granularity.  This is known in this API as the chunk size.
 299  *
 300  * Return: chunk size in bytes
 301  */
 302 static inline unsigned int crypto_skcipher_chunksize(
 303         struct crypto_skcipher *tfm)
 304 {
 305         return crypto_skcipher_alg_chunksize(crypto_skcipher_alg(tfm));
 306 }
 307
 308 /**
 309  * crypto_skcipher_blocksize() - obtain block size of cipher
 310  * @tfm: cipher handle
 311  *
 312  * The block size for the skcipher referenced with the cipher handle is
 313  * returned. The caller may use that information to allocate appropriate
 314  * memory for the data returned by the encryption or decryption operation
 315  *
 316  * Return: block size of cipher
 317  */
 318 static inline unsigned int crypto_skcipher_blocksize(
 319         struct crypto_skcipher *tfm)
 320 {
 321         return crypto_tfm_alg_blocksize(crypto_skcipher_tfm(tfm));
 322 }
 323
 324 static inline unsigned int crypto_skcipher_alignmask(
 325         struct crypto_skcipher *tfm)
 326 {
 327         return crypto_tfm_alg_alignmask(crypto_skcipher_tfm(tfm));
 328 }
 329
 330 static inline u32 crypto_skcipher_get_flags(struct crypto_skcipher *tfm)
 331 {
 332         return crypto_tfm_get_flags(crypto_skcipher_tfm(tfm));
 333 }
 334
 335 static inline void crypto_skcipher_set_flags(struct crypto_skcipher *tfm,
 336                                                u32 flags)
 337 {
 338         crypto_tfm_set_flags(crypto_skcipher_tfm(tfm), flags);
 339 }
 340
 341 static inline void crypto_skcipher_clear_flags(struct crypto_skcipher *tfm,
 342                                                  u32 flags)
 343 {
 344         crypto_tfm_clear_flags(crypto_skcipher_tfm(tfm), flags);
 345 }
 346
 347 /**
 348  * crypto_skcipher_setkey() - set key for cipher
 349  * @tfm: cipher handle
 350  * @key: buffer holding the key
 351  * @keylen: length of the key in bytes
 352  *
 353  * The caller provided key is set for the skcipher referenced by the cipher
 354  * handle.
 355  *
 356  * Note, the key length determines the cipher type. Many block ciphers implement
 357  * different cipher modes depending on the key size, such as AES-128 vs AES-192
 358  * vs. AES-256. When providing a 16 byte key for an AES cipher handle, AES-128
 359  * is performed.
 360  *
 361  * Return: 0 if the setting of the key was successful; < 0 if an error occurred
 362  */
 363 static inline int crypto_skcipher_setkey(struct crypto_skcipher *tfm,
 364                                          const u8 *key, unsigned int keylen)
 365 {
 366         return tfm->setkey(tfm, key, keylen);
 367 }
 368
 369 static inline bool crypto_skcipher_has_setkey(struct crypto_skcipher *tfm)
 370 {
 371         return tfm->keysize;
 372 }
 373
 374 static inline unsigned int crypto_skcipher_default_keysize(
 375         struct crypto_skcipher *tfm)
 376 {
 377         return tfm->keysize;
 378 }
 379
 380 /**
 381  * crypto_skcipher_reqtfm() - obtain cipher handle from request
 382  * @req: skcipher_request out of which the cipher handle is to be obtained
 383  *
 384  * Return the crypto_skcipher handle when furnishing an skcipher_request
 385  * data structure.
 386  *
 387  * Return: crypto_skcipher handle
 388  */
 389 static inline struct crypto_skcipher *crypto_skcipher_reqtfm(
 390         struct skcipher_request *req)
 391 {
 392         return __crypto_skcipher_cast(req->base.tfm);
 393 }
 394
 395 /**
 396  * crypto_skcipher_encrypt() - encrypt plaintext
 397  * @req: reference to the skcipher_request handle that holds all information
 398  *       needed to perform the cipher operation
 399  *
 400  * Encrypt plaintext data using the skcipher_request handle. That data
 401  * structure and how it is filled with data is discussed with the
 402  * skcipher_request_* functions.
 403  *
 404  * Return: 0 if the cipher operation was successful; < 0 if an error occurred
 405  */
 406 static inline int crypto_skcipher_encrypt(struct skcipher_request *req)
 407 {
 408         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 409
 410         return tfm->encrypt(req);
 411 }
 412
 413 /**
 414  * crypto_skcipher_decrypt() - decrypt ciphertext
 415  * @req: reference to the skcipher_request handle that holds all information
 416  *       needed to perform the cipher operation
 417  *
 418  * Decrypt ciphertext data using the skcipher_request handle. That data
 419  * structure and how it is filled with data is discussed with the
 420  * skcipher_request_* functions.
 421  *
 422  * Return: 0 if the cipher operation was successful; < 0 if an error occurred
 423  */
 424 static inline int crypto_skcipher_decrypt(struct skcipher_request *req)
 425 {
 426         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 427
 428         return tfm->decrypt(req);
 429 }
 430
 431 /**
 432  * DOC: Symmetric Key Cipher Request Handle
 433  *
 434  * The skcipher_request data structure contains all pointers to data
 435  * required for the symmetric key cipher operation. This includes the cipher
 436  * handle (which can be used by multiple skcipher_request instances), pointer
 437  * to plaintext and ciphertext, asynchronous callback function, etc. It acts
 438  * as a handle to the skcipher_request_* API calls in a similar way as
 439  * skcipher handle to the crypto_skcipher_* API calls.
 440  */
 441
 442 /**
 443  * crypto_skcipher_reqsize() - obtain size of the request data structure
 444  * @tfm: cipher handle
 445  *
 446  * Return: number of bytes
 447  */
 448 static inline unsigned int crypto_skcipher_reqsize(struct crypto_skcipher *tfm)
 449 {
 450         return tfm->reqsize;
 451 }
 452
 453 /**
 454  * skcipher_request_set_tfm() - update cipher handle reference in request
 455  * @req: request handle to be modified
 456  * @tfm: cipher handle that shall be added to the request handle
 457  *
 458  * Allow the caller to replace the existing skcipher handle in the request
 459  * data structure with a different one.
 460  */
 461 static inline void skcipher_request_set_tfm(struct skcipher_request *req,
 462                                             struct crypto_skcipher *tfm)
 463 {
 464         req->base.tfm = crypto_skcipher_tfm(tfm);
 465 }
 466
 467 static inline struct skcipher_request *skcipher_request_cast(
 468         struct crypto_async_request *req)
 469 {
 470         return container_of(req, struct skcipher_request, base);
 471 }
 472
 473 /**
 474  * skcipher_request_alloc() - allocate request data structure
 475  * @tfm: cipher handle to be registered with the request
 476  * @gfp: memory allocation flag that is handed to kmalloc by the API call.
 477  *
 478  * Allocate the request data structure that must be used with the skcipher
 479  * encrypt and decrypt API calls. During the allocation, the provided skcipher
 480  * handle is registered in the request data structure.
 481  *
 482  * Return: allocated request handle in case of success, or NULL if out of memory
 483  */
 484 static inline struct skcipher_request *skcipher_request_alloc(
 485         struct crypto_skcipher *tfm, gfp_t gfp)
 486 {
 487         struct skcipher_request *req;
 488
 489         req = kmalloc(sizeof(struct skcipher_request) +
 490                       crypto_skcipher_reqsize(tfm), gfp);
 491
 492         if (likely(req))
 493                 skcipher_request_set_tfm(req, tfm);
 494
 495         return req;
 496 }
 497
 498 /**
 499  * skcipher_request_free() - zeroize and free request data structure
 500  * @req: request data structure cipher handle to be freed
 501  */
 502 static inline void skcipher_request_free(struct skcipher_request *req)
 503 {
 504         kzfree(req);
 505 }
 506
 507 static inline void skcipher_request_zero(struct skcipher_request *req)
 508 {
 509         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 510
 511         memzero_explicit(req, sizeof(*req) + crypto_skcipher_reqsize(tfm));
 512 }
 513
 514 /**
 515  * skcipher_request_set_callback() - set asynchronous callback function
 516  * @req: request handle
 517  * @flags: specify zero or an ORing of the flags
 518  *         CRYPTO_TFM_REQ_MAY_BACKLOG the request queue may back log and
 519  *         increase the wait queue beyond the initial maximum size;
 520  *         CRYPTO_TFM_REQ_MAY_SLEEP the request processing may sleep
 521  * @compl: callback function pointer to be registered with the request handle
 522  * @data: The data pointer refers to memory that is not used by the kernel
 523  *        crypto API, but provided to the callback function for it to use. Here,
 524  *        the caller can provide a reference to memory the callback function can
 525  *        operate on. As the callback function is invoked asynchronously to the
 526  *        related functionality, it may need to access data structures of the
 527  *        related functionality which can be referenced using this pointer. The
 528  *        callback function can access the memory via the "data" field in the
 529  *        crypto_async_request data structure provided to the callback function.
 530  *
 531  * This function allows setting the callback function that is triggered once the
 532  * cipher operation completes.
 533  *
 534  * The callback function is registered with the skcipher_request handle and
 535  * must comply with the following template
 536  *
 537  *      void callback_function(struct crypto_async_request *req, int error)
 538  */
 539 static inline void skcipher_request_set_callback(struct skcipher_request *req,
 540                                                  u32 flags,
 541                                                  crypto_completion_t compl,
 542                                                  void *data)
 543 {
 544         req->base.complete = compl;
 545         req->base.data = data;
 546         req->base.flags = flags;
 547 }
 548
 549 /**
 550  * skcipher_request_set_crypt() - set data buffers
 551  * @req: request handle
 552  * @src: source scatter / gather list
 553  * @dst: destination scatter / gather list
 554  * @cryptlen: number of bytes to process from @src
 555  * @iv: IV for the cipher operation which must comply with the IV size defined
 556  *      by crypto_skcipher_ivsize
 557  *
 558  * This function allows setting of the source data and destination data
 559  * scatter / gather lists.
 560  *
 561  * For encryption, the source is treated as the plaintext and the
 562  * destination is the ciphertext. For a decryption operation, the use is
 563  * reversed - the source is the ciphertext and the destination is the plaintext.
 564  */
 565 static inline void skcipher_request_set_crypt(
 566         struct skcipher_request *req,
 567         struct scatterlist *src, struct scatterlist *dst,
 568         unsigned int cryptlen, void *iv)
 569 {
 570         req->src = src;
 571         req->dst = dst;
 572         req->cryptlen = cryptlen;
 573         req->iv = iv;
 574 }
 575
 576 #endif  /* _CRYPTO_SKCIPHER_H */
 577