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 if (nbytes > unaligned) 59 nbytes = unaligned; 60 } 61 62 walk->entrylen -= nbytes; 63 return nbytes; 64 } 65 66 static int hash_walk_new_entry(struct crypto_hash_walk *walk) 67 { 68 struct scatterlist *sg; 69 70 sg = walk->sg; 71 walk->pg = sg_page(sg); 72 walk->offset = sg->offset; 73 walk->entrylen = sg->length; 74 75 if (walk->entrylen > walk->total) 76 walk->entrylen = walk->total; 77 walk->total -= walk->entrylen; 78 79 return hash_walk_next(walk); 80 } 81 82 int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err) 83 { 84 unsigned int alignmask = walk->alignmask; 85 unsigned int nbytes = walk->entrylen; 86 87 walk->data -= walk->offset; 88 89 if (nbytes && walk->offset & alignmask && !err) { 90 walk->offset = ALIGN(walk->offset, alignmask + 1); 91 walk->data += walk->offset; 92 93 nbytes = min(nbytes, 94 ((unsigned int)(PAGE_SIZE)) - walk->offset); 95 walk->entrylen -= nbytes; 96 97 return nbytes; 98 } 99 100 if (walk->flags & CRYPTO_ALG_ASYNC) 101 kunmap(walk->pg); 102 else { 103 kunmap_atomic(walk->data); 104 /* 105 * The may sleep test only makes sense for sync users. 106 * Async users don't need to sleep here anyway. 107 */ 108 crypto_yield(walk->flags); 109 } 110 111 if (err) 112 return err; 113 114 if (nbytes) { 115 walk->offset = 0; 116 walk->pg++; 117 return hash_walk_next(walk); 118 } 119 120 if (!walk->total) 121 return 0; 122 123 walk->sg = scatterwalk_sg_next(walk->sg); 124 125 return hash_walk_new_entry(walk); 126 } 127 EXPORT_SYMBOL_GPL(crypto_hash_walk_done); 128 129 int crypto_hash_walk_first(struct ahash_request *req, 130 struct crypto_hash_walk *walk) 131 { 132 walk->total = req->nbytes; 133 134 if (!walk->total) { 135 walk->entrylen = 0; 136 return 0; 137 } 138 139 walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req)); 140 walk->sg = req->src; 141 walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK; 142 143 return hash_walk_new_entry(walk); 144 } 145 EXPORT_SYMBOL_GPL(crypto_hash_walk_first); 146 147 int crypto_ahash_walk_first(struct ahash_request *req, 148 struct crypto_hash_walk *walk) 149 { 150 walk->total = req->nbytes; 151 152 if (!walk->total) { 153 walk->entrylen = 0; 154 return 0; 155 } 156 157 walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req)); 158 walk->sg = req->src; 159 walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK; 160 walk->flags |= CRYPTO_ALG_ASYNC; 161 162 BUILD_BUG_ON(CRYPTO_TFM_REQ_MASK & CRYPTO_ALG_ASYNC); 163 164 return hash_walk_new_entry(walk); 165 } 166 EXPORT_SYMBOL_GPL(crypto_ahash_walk_first); 167 168 int crypto_hash_walk_first_compat(struct hash_desc *hdesc, 169 struct crypto_hash_walk *walk, 170 struct scatterlist *sg, unsigned int len) 171 { 172 walk->total = len; 173 174 if (!walk->total) { 175 walk->entrylen = 0; 176 return 0; 177 } 178 179 walk->alignmask = crypto_hash_alignmask(hdesc->tfm); 180 walk->sg = sg; 181 walk->flags = hdesc->flags & CRYPTO_TFM_REQ_MASK; 182 183 return hash_walk_new_entry(walk); 184 } 185 186 static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key, 187 unsigned int keylen) 188 { 189 unsigned long alignmask = crypto_ahash_alignmask(tfm); 190 int ret; 191 u8 *buffer, *alignbuffer; 192 unsigned long absize; 193 194 absize = keylen + alignmask; 195 buffer = kmalloc(absize, GFP_KERNEL); 196 if (!buffer) 197 return -ENOMEM; 198 199 alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1); 200 memcpy(alignbuffer, key, keylen); 201 ret = tfm->setkey(tfm, alignbuffer, keylen); 202 kzfree(buffer); 203 return ret; 204 } 205 206 int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key, 207 unsigned int keylen) 208 { 209 unsigned long alignmask = crypto_ahash_alignmask(tfm); 210 211 if ((unsigned long)key & alignmask) 212 return ahash_setkey_unaligned(tfm, key, keylen); 213 214 return tfm->setkey(tfm, key, keylen); 215 } 216 EXPORT_SYMBOL_GPL(crypto_ahash_setkey); 217 218 static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key, 219 unsigned int keylen) 220 { 221 return -ENOSYS; 222 } 223 224 static inline unsigned int ahash_align_buffer_size(unsigned len, 225 unsigned long mask) 226 { 227 return len + (mask & ~(crypto_tfm_ctx_alignment() - 1)); 228 } 229 230 static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt) 231 { 232 struct crypto_ahash *tfm = crypto_ahash_reqtfm(req); 233 unsigned long alignmask = crypto_ahash_alignmask(tfm); 234 unsigned int ds = crypto_ahash_digestsize(tfm); 235 struct ahash_request_priv *priv; 236 237 priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask), 238 (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ? 239 GFP_KERNEL : GFP_ATOMIC); 240 if (!priv) 241 return -ENOMEM; 242 243 /* 244 * WARNING: Voodoo programming below! 245 * 246 * The code below is obscure and hard to understand, thus explanation 247 * is necessary. See include/crypto/hash.h and include/linux/crypto.h 248 * to understand the layout of structures used here! 249 * 250 * The code here will replace portions of the ORIGINAL request with 251 * pointers to new code and buffers so the hashing operation can store 252 * the result in aligned buffer. We will call the modified request 253 * an ADJUSTED request. 254 * 255 * The newly mangled request will look as such: 256 * 257 * req { 258 * .result = ADJUSTED[new aligned buffer] 259 * .base.complete = ADJUSTED[pointer to completion function] 260 * .base.data = ADJUSTED[*req (pointer to self)] 261 * .priv = ADJUSTED[new priv] { 262 * .result = ORIGINAL(result) 263 * .complete = ORIGINAL(base.complete) 264 * .data = ORIGINAL(base.data) 265 * } 266 */ 267 268 priv->result = req->result; 269 priv->complete = req->base.complete; 270 priv->data = req->base.data; 271 /* 272 * WARNING: We do not backup req->priv here! The req->priv 273 * is for internal use of the Crypto API and the 274 * user must _NOT_ _EVER_ depend on it's content! 275 */ 276 277 req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1); 278 req->base.complete = cplt; 279 req->base.data = req; 280 req->priv = priv; 281 282 return 0; 283 } 284 285 static void ahash_restore_req(struct ahash_request *req) 286 { 287 struct ahash_request_priv *priv = req->priv; 288 289 /* Restore the original crypto request. */ 290 req->result = priv->result; 291 req->base.complete = priv->complete; 292 req->base.data = priv->data; 293 req->priv = NULL; 294 295 /* Free the req->priv.priv from the ADJUSTED request. */ 296 kzfree(priv); 297 } 298 299 static void ahash_op_unaligned_finish(struct ahash_request *req, int err) 300 { 301 struct ahash_request_priv *priv = req->priv; 302 303 if (err == -EINPROGRESS) 304 return; 305 306 if (!err) 307 memcpy(priv->result, req->result, 308 crypto_ahash_digestsize(crypto_ahash_reqtfm(req))); 309 310 ahash_restore_req(req); 311 } 312 313 static void ahash_op_unaligned_done(struct crypto_async_request *req, int err) 314 { 315 struct ahash_request *areq = req->data; 316 317 /* 318 * Restore the original request, see ahash_op_unaligned() for what 319 * goes where. 320 * 321 * The "struct ahash_request *req" here is in fact the "req.base" 322 * from the ADJUSTED request from ahash_op_unaligned(), thus as it 323 * is a pointer to self, it is also the ADJUSTED "req" . 324 */ 325 326 /* First copy req->result into req->priv.result */ 327 ahash_op_unaligned_finish(areq, err); 328 329 /* Complete the ORIGINAL request. */ 330 areq->base.complete(&areq->base, err); 331 } 332 333 static int ahash_op_unaligned(struct ahash_request *req, 334 int (*op)(struct ahash_request *)) 335 { 336 int err; 337 338 err = ahash_save_req(req, ahash_op_unaligned_done); 339 if (err) 340 return err; 341 342 err = op(req); 343 ahash_op_unaligned_finish(req, err); 344 345 return err; 346 } 347 348 static int crypto_ahash_op(struct ahash_request *req, 349 int (*op)(struct ahash_request *)) 350 { 351 struct crypto_ahash *tfm = crypto_ahash_reqtfm(req); 352 unsigned long alignmask = crypto_ahash_alignmask(tfm); 353 354 if ((unsigned long)req->result & alignmask) 355 return ahash_op_unaligned(req, op); 356 357 return op(req); 358 } 359 360 int crypto_ahash_final(struct ahash_request *req) 361 { 362 return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final); 363 } 364 EXPORT_SYMBOL_GPL(crypto_ahash_final); 365 366 int crypto_ahash_finup(struct ahash_request *req) 367 { 368 return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup); 369 } 370 EXPORT_SYMBOL_GPL(crypto_ahash_finup); 371 372 int crypto_ahash_digest(struct ahash_request *req) 373 { 374 return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->digest); 375 } 376 EXPORT_SYMBOL_GPL(crypto_ahash_digest); 377 378 static void ahash_def_finup_finish2(struct ahash_request *req, int err) 379 { 380 struct ahash_request_priv *priv = req->priv; 381 382 if (err == -EINPROGRESS) 383 return; 384 385 if (!err) 386 memcpy(priv->result, req->result, 387 crypto_ahash_digestsize(crypto_ahash_reqtfm(req))); 388 389 ahash_restore_req(req); 390 } 391 392 static void ahash_def_finup_done2(struct crypto_async_request *req, int err) 393 { 394 struct ahash_request *areq = req->data; 395 396 ahash_def_finup_finish2(areq, err); 397 398 areq->base.complete(&areq->base, err); 399 } 400 401 static int ahash_def_finup_finish1(struct ahash_request *req, int err) 402 { 403 if (err) 404 goto out; 405 406 req->base.complete = ahash_def_finup_done2; 407 req->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP; 408 err = crypto_ahash_reqtfm(req)->final(req); 409 410 out: 411 ahash_def_finup_finish2(req, err); 412 return err; 413 } 414 415 static void ahash_def_finup_done1(struct crypto_async_request *req, int err) 416 { 417 struct ahash_request *areq = req->data; 418 419 err = ahash_def_finup_finish1(areq, err); 420 421 areq->base.complete(&areq->base, err); 422 } 423 424 static int ahash_def_finup(struct ahash_request *req) 425 { 426 struct crypto_ahash *tfm = crypto_ahash_reqtfm(req); 427 int err; 428 429 err = ahash_save_req(req, ahash_def_finup_done1); 430 if (err) 431 return err; 432 433 err = tfm->update(req); 434 return ahash_def_finup_finish1(req, err); 435 } 436 437 static int ahash_no_export(struct ahash_request *req, void *out) 438 { 439 return -ENOSYS; 440 } 441 442 static int ahash_no_import(struct ahash_request *req, const void *in) 443 { 444 return -ENOSYS; 445 } 446 447 static int crypto_ahash_init_tfm(struct crypto_tfm *tfm) 448 { 449 struct crypto_ahash *hash = __crypto_ahash_cast(tfm); 450 struct ahash_alg *alg = crypto_ahash_alg(hash); 451 452 hash->setkey = ahash_nosetkey; 453 hash->export = ahash_no_export; 454 hash->import = ahash_no_import; 455 456 if (tfm->__crt_alg->cra_type != &crypto_ahash_type) 457 return crypto_init_shash_ops_async(tfm); 458 459 hash->init = alg->init; 460 hash->update = alg->update; 461 hash->final = alg->final; 462 hash->finup = alg->finup ?: ahash_def_finup; 463 hash->digest = alg->digest; 464 465 if (alg->setkey) 466 hash->setkey = alg->setkey; 467 if (alg->export) 468 hash->export = alg->export; 469 if (alg->import) 470 hash->import = alg->import; 471 472 return 0; 473 } 474 475 static unsigned int crypto_ahash_extsize(struct crypto_alg *alg) 476 { 477 if (alg->cra_type == &crypto_ahash_type) 478 return alg->cra_ctxsize; 479 480 return sizeof(struct crypto_shash *); 481 } 482 483 #ifdef CONFIG_NET 484 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg) 485 { 486 struct crypto_report_hash rhash; 487 488 strncpy(rhash.type, "ahash", sizeof(rhash.type)); 489 490 rhash.blocksize = alg->cra_blocksize; 491 rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize; 492 493 if (nla_put(skb, CRYPTOCFGA_REPORT_HASH, 494 sizeof(struct crypto_report_hash), &rhash)) 495 goto nla_put_failure; 496 return 0; 497 498 nla_put_failure: 499 return -EMSGSIZE; 500 } 501 #else 502 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg) 503 { 504 return -ENOSYS; 505 } 506 #endif 507 508 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg) 509 __attribute__ ((unused)); 510 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg) 511 { 512 seq_printf(m, "type : ahash\n"); 513 seq_printf(m, "async : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ? 514 "yes" : "no"); 515 seq_printf(m, "blocksize : %u\n", alg->cra_blocksize); 516 seq_printf(m, "digestsize : %u\n", 517 __crypto_hash_alg_common(alg)->digestsize); 518 } 519 520 const struct crypto_type crypto_ahash_type = { 521 .extsize = crypto_ahash_extsize, 522 .init_tfm = crypto_ahash_init_tfm, 523 #ifdef CONFIG_PROC_FS 524 .show = crypto_ahash_show, 525 #endif 526 .report = crypto_ahash_report, 527 .maskclear = ~CRYPTO_ALG_TYPE_MASK, 528 .maskset = CRYPTO_ALG_TYPE_AHASH_MASK, 529 .type = CRYPTO_ALG_TYPE_AHASH, 530 .tfmsize = offsetof(struct crypto_ahash, base), 531 }; 532 EXPORT_SYMBOL_GPL(crypto_ahash_type); 533 534 struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type, 535 u32 mask) 536 { 537 return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask); 538 } 539 EXPORT_SYMBOL_GPL(crypto_alloc_ahash); 540 541 static int ahash_prepare_alg(struct ahash_alg *alg) 542 { 543 struct crypto_alg *base = &alg->halg.base; 544 545 if (alg->halg.digestsize > PAGE_SIZE / 8 || 546 alg->halg.statesize > PAGE_SIZE / 8) 547 return -EINVAL; 548 549 base->cra_type = &crypto_ahash_type; 550 base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK; 551 base->cra_flags |= CRYPTO_ALG_TYPE_AHASH; 552 553 return 0; 554 } 555 556 int crypto_register_ahash(struct ahash_alg *alg) 557 { 558 struct crypto_alg *base = &alg->halg.base; 559 int err; 560 561 err = ahash_prepare_alg(alg); 562 if (err) 563 return err; 564 565 return crypto_register_alg(base); 566 } 567 EXPORT_SYMBOL_GPL(crypto_register_ahash); 568 569 int crypto_unregister_ahash(struct ahash_alg *alg) 570 { 571 return crypto_unregister_alg(&alg->halg.base); 572 } 573 EXPORT_SYMBOL_GPL(crypto_unregister_ahash); 574 575 int ahash_register_instance(struct crypto_template *tmpl, 576 struct ahash_instance *inst) 577 { 578 int err; 579 580 err = ahash_prepare_alg(&inst->alg); 581 if (err) 582 return err; 583 584 return crypto_register_instance(tmpl, ahash_crypto_instance(inst)); 585 } 586 EXPORT_SYMBOL_GPL(ahash_register_instance); 587 588 void ahash_free_instance(struct crypto_instance *inst) 589 { 590 crypto_drop_spawn(crypto_instance_ctx(inst)); 591 kfree(ahash_instance(inst)); 592 } 593 EXPORT_SYMBOL_GPL(ahash_free_instance); 594 595 int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn, 596 struct hash_alg_common *alg, 597 struct crypto_instance *inst) 598 { 599 return crypto_init_spawn2(&spawn->base, &alg->base, inst, 600 &crypto_ahash_type); 601 } 602 EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn); 603 604 struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask) 605 { 606 struct crypto_alg *alg; 607 608 alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask); 609 return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg); 610 } 611 EXPORT_SYMBOL_GPL(ahash_attr_alg); 612 613 MODULE_LICENSE("GPL"); 614 MODULE_DESCRIPTION("Asynchronous cryptographic hash type"); 615