1 /* 2 * Asynchronous Cryptographic Hash operations. 3 * 4 * This is the asynchronous version of hash.c with notification of 5 * completion via a callback. 6 * 7 * Copyright (c) 2008 Loc Ho <lho@amcc.com> 8 * 9 * This program is free software; you can redistribute it and/or modify it 10 * under the terms of the GNU General Public License as published by the Free 11 * Software Foundation; either version 2 of the License, or (at your option) 12 * any later version. 13 * 14 */ 15 16 #include <crypto/internal/hash.h> 17 #include <crypto/scatterwalk.h> 18 #include <linux/bug.h> 19 #include <linux/err.h> 20 #include <linux/kernel.h> 21 #include <linux/module.h> 22 #include <linux/sched.h> 23 #include <linux/slab.h> 24 #include <linux/seq_file.h> 25 #include <linux/cryptouser.h> 26 #include <net/netlink.h> 27 28 #include "internal.h" 29 30 struct ahash_request_priv { 31 crypto_completion_t complete; 32 void *data; 33 u8 *result; 34 void *ubuf[] CRYPTO_MINALIGN_ATTR; 35 }; 36 37 static inline struct ahash_alg *crypto_ahash_alg(struct crypto_ahash *hash) 38 { 39 return container_of(crypto_hash_alg_common(hash), struct ahash_alg, 40 halg); 41 } 42 43 static int hash_walk_next(struct crypto_hash_walk *walk) 44 { 45 unsigned int alignmask = walk->alignmask; 46 unsigned int offset = walk->offset; 47 unsigned int nbytes = min(walk->entrylen, 48 ((unsigned int)(PAGE_SIZE)) - offset); 49 50 if (walk->flags & CRYPTO_ALG_ASYNC) 51 walk->data = kmap(walk->pg); 52 else 53 walk->data = kmap_atomic(walk->pg); 54 walk->data += offset; 55 56 if (offset & alignmask) { 57 unsigned int unaligned = alignmask + 1 - (offset & alignmask); 58 59 if (nbytes > unaligned) 60 nbytes = unaligned; 61 } 62 63 walk->entrylen -= nbytes; 64 return nbytes; 65 } 66 67 static int hash_walk_new_entry(struct crypto_hash_walk *walk) 68 { 69 struct scatterlist *sg; 70 71 sg = walk->sg; 72 walk->offset = sg->offset; 73 walk->pg = sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT); 74 walk->offset = offset_in_page(walk->offset); 75 walk->entrylen = sg->length; 76 77 if (walk->entrylen > walk->total) 78 walk->entrylen = walk->total; 79 walk->total -= walk->entrylen; 80 81 return hash_walk_next(walk); 82 } 83 84 int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err) 85 { 86 unsigned int alignmask = walk->alignmask; 87 unsigned int nbytes = walk->entrylen; 88 89 walk->data -= walk->offset; 90 91 if (nbytes && walk->offset & alignmask && !err) { 92 walk->offset = ALIGN(walk->offset, alignmask + 1); 93 walk->data += walk->offset; 94 95 nbytes = min(nbytes, 96 ((unsigned int)(PAGE_SIZE)) - walk->offset); 97 walk->entrylen -= nbytes; 98 99 return nbytes; 100 } 101 102 if (walk->flags & CRYPTO_ALG_ASYNC) 103 kunmap(walk->pg); 104 else { 105 kunmap_atomic(walk->data); 106 /* 107 * The may sleep test only makes sense for sync users. 108 * Async users don't need to sleep here anyway. 109 */ 110 crypto_yield(walk->flags); 111 } 112 113 if (err) 114 return err; 115 116 if (nbytes) { 117 walk->offset = 0; 118 walk->pg++; 119 return hash_walk_next(walk); 120 } 121 122 if (!walk->total) 123 return 0; 124 125 walk->sg = sg_next(walk->sg); 126 127 return hash_walk_new_entry(walk); 128 } 129 EXPORT_SYMBOL_GPL(crypto_hash_walk_done); 130 131 int crypto_hash_walk_first(struct ahash_request *req, 132 struct crypto_hash_walk *walk) 133 { 134 walk->total = req->nbytes; 135 136 if (!walk->total) { 137 walk->entrylen = 0; 138 return 0; 139 } 140 141 walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req)); 142 walk->sg = req->src; 143 walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK; 144 145 return hash_walk_new_entry(walk); 146 } 147 EXPORT_SYMBOL_GPL(crypto_hash_walk_first); 148 149 int crypto_ahash_walk_first(struct ahash_request *req, 150 struct crypto_hash_walk *walk) 151 { 152 walk->total = req->nbytes; 153 154 if (!walk->total) { 155 walk->entrylen = 0; 156 return 0; 157 } 158 159 walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req)); 160 walk->sg = req->src; 161 walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK; 162 walk->flags |= CRYPTO_ALG_ASYNC; 163 164 BUILD_BUG_ON(CRYPTO_TFM_REQ_MASK & CRYPTO_ALG_ASYNC); 165 166 return hash_walk_new_entry(walk); 167 } 168 EXPORT_SYMBOL_GPL(crypto_ahash_walk_first); 169 170 static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key, 171 unsigned int keylen) 172 { 173 unsigned long alignmask = crypto_ahash_alignmask(tfm); 174 int ret; 175 u8 *buffer, *alignbuffer; 176 unsigned long absize; 177 178 absize = keylen + alignmask; 179 buffer = kmalloc(absize, GFP_KERNEL); 180 if (!buffer) 181 return -ENOMEM; 182 183 alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1); 184 memcpy(alignbuffer, key, keylen); 185 ret = tfm->setkey(tfm, alignbuffer, keylen); 186 kzfree(buffer); 187 return ret; 188 } 189 190 int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key, 191 unsigned int keylen) 192 { 193 unsigned long alignmask = crypto_ahash_alignmask(tfm); 194 195 if ((unsigned long)key & alignmask) 196 return ahash_setkey_unaligned(tfm, key, keylen); 197 198 return tfm->setkey(tfm, key, keylen); 199 } 200 EXPORT_SYMBOL_GPL(crypto_ahash_setkey); 201 202 static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key, 203 unsigned int keylen) 204 { 205 return -ENOSYS; 206 } 207 208 static inline unsigned int ahash_align_buffer_size(unsigned len, 209 unsigned long mask) 210 { 211 return len + (mask & ~(crypto_tfm_ctx_alignment() - 1)); 212 } 213 214 static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt) 215 { 216 struct crypto_ahash *tfm = crypto_ahash_reqtfm(req); 217 unsigned long alignmask = crypto_ahash_alignmask(tfm); 218 unsigned int ds = crypto_ahash_digestsize(tfm); 219 struct ahash_request_priv *priv; 220 221 priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask), 222 (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ? 223 GFP_KERNEL : GFP_ATOMIC); 224 if (!priv) 225 return -ENOMEM; 226 227 /* 228 * WARNING: Voodoo programming below! 229 * 230 * The code below is obscure and hard to understand, thus explanation 231 * is necessary. See include/crypto/hash.h and include/linux/crypto.h 232 * to understand the layout of structures used here! 233 * 234 * The code here will replace portions of the ORIGINAL request with 235 * pointers to new code and buffers so the hashing operation can store 236 * the result in aligned buffer. We will call the modified request 237 * an ADJUSTED request. 238 * 239 * The newly mangled request will look as such: 240 * 241 * req { 242 * .result = ADJUSTED[new aligned buffer] 243 * .base.complete = ADJUSTED[pointer to completion function] 244 * .base.data = ADJUSTED[*req (pointer to self)] 245 * .priv = ADJUSTED[new priv] { 246 * .result = ORIGINAL(result) 247 * .complete = ORIGINAL(base.complete) 248 * .data = ORIGINAL(base.data) 249 * } 250 */ 251 252 priv->result = req->result; 253 priv->complete = req->base.complete; 254 priv->data = req->base.data; 255 /* 256 * WARNING: We do not backup req->priv here! The req->priv 257 * is for internal use of the Crypto API and the 258 * user must _NOT_ _EVER_ depend on it's content! 259 */ 260 261 req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1); 262 req->base.complete = cplt; 263 req->base.data = req; 264 req->priv = priv; 265 266 return 0; 267 } 268 269 static void ahash_restore_req(struct ahash_request *req) 270 { 271 struct ahash_request_priv *priv = req->priv; 272 273 /* Restore the original crypto request. */ 274 req->result = priv->result; 275 req->base.complete = priv->complete; 276 req->base.data = priv->data; 277 req->priv = NULL; 278 279 /* Free the req->priv.priv from the ADJUSTED request. */ 280 kzfree(priv); 281 } 282 283 static void ahash_op_unaligned_finish(struct ahash_request *req, int err) 284 { 285 struct ahash_request_priv *priv = req->priv; 286 287 if (err == -EINPROGRESS) 288 return; 289 290 if (!err) 291 memcpy(priv->result, req->result, 292 crypto_ahash_digestsize(crypto_ahash_reqtfm(req))); 293 294 ahash_restore_req(req); 295 } 296 297 static void ahash_op_unaligned_done(struct crypto_async_request *req, int err) 298 { 299 struct ahash_request *areq = req->data; 300 301 /* 302 * Restore the original request, see ahash_op_unaligned() for what 303 * goes where. 304 * 305 * The "struct ahash_request *req" here is in fact the "req.base" 306 * from the ADJUSTED request from ahash_op_unaligned(), thus as it 307 * is a pointer to self, it is also the ADJUSTED "req" . 308 */ 309 310 /* First copy req->result into req->priv.result */ 311 ahash_op_unaligned_finish(areq, err); 312 313 /* Complete the ORIGINAL request. */ 314 areq->base.complete(&areq->base, err); 315 } 316 317 static int ahash_op_unaligned(struct ahash_request *req, 318 int (*op)(struct ahash_request *)) 319 { 320 int err; 321 322 err = ahash_save_req(req, ahash_op_unaligned_done); 323 if (err) 324 return err; 325 326 err = op(req); 327 ahash_op_unaligned_finish(req, err); 328 329 return err; 330 } 331 332 static int crypto_ahash_op(struct ahash_request *req, 333 int (*op)(struct ahash_request *)) 334 { 335 struct crypto_ahash *tfm = crypto_ahash_reqtfm(req); 336 unsigned long alignmask = crypto_ahash_alignmask(tfm); 337 338 if ((unsigned long)req->result & alignmask) 339 return ahash_op_unaligned(req, op); 340 341 return op(req); 342 } 343 344 int crypto_ahash_final(struct ahash_request *req) 345 { 346 return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final); 347 } 348 EXPORT_SYMBOL_GPL(crypto_ahash_final); 349 350 int crypto_ahash_finup(struct ahash_request *req) 351 { 352 return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup); 353 } 354 EXPORT_SYMBOL_GPL(crypto_ahash_finup); 355 356 int crypto_ahash_digest(struct ahash_request *req) 357 { 358 return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->digest); 359 } 360 EXPORT_SYMBOL_GPL(crypto_ahash_digest); 361 362 static void ahash_def_finup_finish2(struct ahash_request *req, int err) 363 { 364 struct ahash_request_priv *priv = req->priv; 365 366 if (err == -EINPROGRESS) 367 return; 368 369 if (!err) 370 memcpy(priv->result, req->result, 371 crypto_ahash_digestsize(crypto_ahash_reqtfm(req))); 372 373 ahash_restore_req(req); 374 } 375 376 static void ahash_def_finup_done2(struct crypto_async_request *req, int err) 377 { 378 struct ahash_request *areq = req->data; 379 380 ahash_def_finup_finish2(areq, err); 381 382 areq->base.complete(&areq->base, err); 383 } 384 385 static int ahash_def_finup_finish1(struct ahash_request *req, int err) 386 { 387 if (err) 388 goto out; 389 390 req->base.complete = ahash_def_finup_done2; 391 req->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP; 392 err = crypto_ahash_reqtfm(req)->final(req); 393 394 out: 395 ahash_def_finup_finish2(req, err); 396 return err; 397 } 398 399 static void ahash_def_finup_done1(struct crypto_async_request *req, int err) 400 { 401 struct ahash_request *areq = req->data; 402 403 err = ahash_def_finup_finish1(areq, err); 404 405 areq->base.complete(&areq->base, err); 406 } 407 408 static int ahash_def_finup(struct ahash_request *req) 409 { 410 struct crypto_ahash *tfm = crypto_ahash_reqtfm(req); 411 int err; 412 413 err = ahash_save_req(req, ahash_def_finup_done1); 414 if (err) 415 return err; 416 417 err = tfm->update(req); 418 return ahash_def_finup_finish1(req, err); 419 } 420 421 static int ahash_no_export(struct ahash_request *req, void *out) 422 { 423 return -ENOSYS; 424 } 425 426 static int ahash_no_import(struct ahash_request *req, const void *in) 427 { 428 return -ENOSYS; 429 } 430 431 static int crypto_ahash_init_tfm(struct crypto_tfm *tfm) 432 { 433 struct crypto_ahash *hash = __crypto_ahash_cast(tfm); 434 struct ahash_alg *alg = crypto_ahash_alg(hash); 435 436 hash->setkey = ahash_nosetkey; 437 hash->has_setkey = false; 438 hash->export = ahash_no_export; 439 hash->import = ahash_no_import; 440 441 if (tfm->__crt_alg->cra_type != &crypto_ahash_type) 442 return crypto_init_shash_ops_async(tfm); 443 444 hash->init = alg->init; 445 hash->update = alg->update; 446 hash->final = alg->final; 447 hash->finup = alg->finup ?: ahash_def_finup; 448 hash->digest = alg->digest; 449 450 if (alg->setkey) { 451 hash->setkey = alg->setkey; 452 hash->has_setkey = true; 453 } 454 if (alg->export) 455 hash->export = alg->export; 456 if (alg->import) 457 hash->import = alg->import; 458 459 return 0; 460 } 461 462 static unsigned int crypto_ahash_extsize(struct crypto_alg *alg) 463 { 464 if (alg->cra_type != &crypto_ahash_type) 465 return sizeof(struct crypto_shash *); 466 467 return crypto_alg_extsize(alg); 468 } 469 470 #ifdef CONFIG_NET 471 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg) 472 { 473 struct crypto_report_hash rhash; 474 475 strncpy(rhash.type, "ahash", sizeof(rhash.type)); 476 477 rhash.blocksize = alg->cra_blocksize; 478 rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize; 479 480 if (nla_put(skb, CRYPTOCFGA_REPORT_HASH, 481 sizeof(struct crypto_report_hash), &rhash)) 482 goto nla_put_failure; 483 return 0; 484 485 nla_put_failure: 486 return -EMSGSIZE; 487 } 488 #else 489 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg) 490 { 491 return -ENOSYS; 492 } 493 #endif 494 495 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg) 496 __attribute__ ((unused)); 497 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg) 498 { 499 seq_printf(m, "type : ahash\n"); 500 seq_printf(m, "async : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ? 501 "yes" : "no"); 502 seq_printf(m, "blocksize : %u\n", alg->cra_blocksize); 503 seq_printf(m, "digestsize : %u\n", 504 __crypto_hash_alg_common(alg)->digestsize); 505 } 506 507 const struct crypto_type crypto_ahash_type = { 508 .extsize = crypto_ahash_extsize, 509 .init_tfm = crypto_ahash_init_tfm, 510 #ifdef CONFIG_PROC_FS 511 .show = crypto_ahash_show, 512 #endif 513 .report = crypto_ahash_report, 514 .maskclear = ~CRYPTO_ALG_TYPE_MASK, 515 .maskset = CRYPTO_ALG_TYPE_AHASH_MASK, 516 .type = CRYPTO_ALG_TYPE_AHASH, 517 .tfmsize = offsetof(struct crypto_ahash, base), 518 }; 519 EXPORT_SYMBOL_GPL(crypto_ahash_type); 520 521 struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type, 522 u32 mask) 523 { 524 return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask); 525 } 526 EXPORT_SYMBOL_GPL(crypto_alloc_ahash); 527 528 int crypto_has_ahash(const char *alg_name, u32 type, u32 mask) 529 { 530 return crypto_type_has_alg(alg_name, &crypto_ahash_type, type, mask); 531 } 532 EXPORT_SYMBOL_GPL(crypto_has_ahash); 533 534 static int ahash_prepare_alg(struct ahash_alg *alg) 535 { 536 struct crypto_alg *base = &alg->halg.base; 537 538 if (alg->halg.digestsize > PAGE_SIZE / 8 || 539 alg->halg.statesize > PAGE_SIZE / 8 || 540 alg->halg.statesize == 0) 541 return -EINVAL; 542 543 base->cra_type = &crypto_ahash_type; 544 base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK; 545 base->cra_flags |= CRYPTO_ALG_TYPE_AHASH; 546 547 return 0; 548 } 549 550 int crypto_register_ahash(struct ahash_alg *alg) 551 { 552 struct crypto_alg *base = &alg->halg.base; 553 int err; 554 555 err = ahash_prepare_alg(alg); 556 if (err) 557 return err; 558 559 return crypto_register_alg(base); 560 } 561 EXPORT_SYMBOL_GPL(crypto_register_ahash); 562 563 int crypto_unregister_ahash(struct ahash_alg *alg) 564 { 565 return crypto_unregister_alg(&alg->halg.base); 566 } 567 EXPORT_SYMBOL_GPL(crypto_unregister_ahash); 568 569 int ahash_register_instance(struct crypto_template *tmpl, 570 struct ahash_instance *inst) 571 { 572 int err; 573 574 err = ahash_prepare_alg(&inst->alg); 575 if (err) 576 return err; 577 578 return crypto_register_instance(tmpl, ahash_crypto_instance(inst)); 579 } 580 EXPORT_SYMBOL_GPL(ahash_register_instance); 581 582 void ahash_free_instance(struct crypto_instance *inst) 583 { 584 crypto_drop_spawn(crypto_instance_ctx(inst)); 585 kfree(ahash_instance(inst)); 586 } 587 EXPORT_SYMBOL_GPL(ahash_free_instance); 588 589 int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn, 590 struct hash_alg_common *alg, 591 struct crypto_instance *inst) 592 { 593 return crypto_init_spawn2(&spawn->base, &alg->base, inst, 594 &crypto_ahash_type); 595 } 596 EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn); 597 598 struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask) 599 { 600 struct crypto_alg *alg; 601 602 alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask); 603 return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg); 604 } 605 EXPORT_SYMBOL_GPL(ahash_attr_alg); 606 607 MODULE_LICENSE("GPL"); 608 MODULE_DESCRIPTION("Asynchronous cryptographic hash type"); 609