1 /* 2 * Copyright (C) 2003 Jana Saout <jana@saout.de> 3 * Copyright (C) 2004 Clemens Fruhwirth <clemens@endorphin.org> 4 * Copyright (C) 2006-2015 Red Hat, Inc. All rights reserved. 5 * Copyright (C) 2013 Milan Broz <gmazyland@gmail.com> 6 * 7 * This file is released under the GPL. 8 */ 9 10 #include <linux/completion.h> 11 #include <linux/err.h> 12 #include <linux/module.h> 13 #include <linux/init.h> 14 #include <linux/kernel.h> 15 #include <linux/bio.h> 16 #include <linux/blkdev.h> 17 #include <linux/mempool.h> 18 #include <linux/slab.h> 19 #include <linux/crypto.h> 20 #include <linux/workqueue.h> 21 #include <linux/kthread.h> 22 #include <linux/backing-dev.h> 23 #include <linux/atomic.h> 24 #include <linux/scatterlist.h> 25 #include <linux/rbtree.h> 26 #include <asm/page.h> 27 #include <asm/unaligned.h> 28 #include <crypto/hash.h> 29 #include <crypto/md5.h> 30 #include <crypto/algapi.h> 31 #include <crypto/skcipher.h> 32 33 #include <linux/device-mapper.h> 34 35 #define DM_MSG_PREFIX "crypt" 36 37 /* 38 * context holding the current state of a multi-part conversion 39 */ 40 struct convert_context { 41 struct completion restart; 42 struct bio *bio_in; 43 struct bio *bio_out; 44 struct bvec_iter iter_in; 45 struct bvec_iter iter_out; 46 sector_t cc_sector; 47 atomic_t cc_pending; 48 struct skcipher_request *req; 49 }; 50 51 /* 52 * per bio private data 53 */ 54 struct dm_crypt_io { 55 struct crypt_config *cc; 56 struct bio *base_bio; 57 struct work_struct work; 58 59 struct convert_context ctx; 60 61 atomic_t io_pending; 62 int error; 63 sector_t sector; 64 65 struct rb_node rb_node; 66 } CRYPTO_MINALIGN_ATTR; 67 68 struct dm_crypt_request { 69 struct convert_context *ctx; 70 struct scatterlist sg_in; 71 struct scatterlist sg_out; 72 sector_t iv_sector; 73 }; 74 75 struct crypt_config; 76 77 struct crypt_iv_operations { 78 int (*ctr)(struct crypt_config *cc, struct dm_target *ti, 79 const char *opts); 80 void (*dtr)(struct crypt_config *cc); 81 int (*init)(struct crypt_config *cc); 82 int (*wipe)(struct crypt_config *cc); 83 int (*generator)(struct crypt_config *cc, u8 *iv, 84 struct dm_crypt_request *dmreq); 85 int (*post)(struct crypt_config *cc, u8 *iv, 86 struct dm_crypt_request *dmreq); 87 }; 88 89 struct iv_essiv_private { 90 struct crypto_ahash *hash_tfm; 91 u8 *salt; 92 }; 93 94 struct iv_benbi_private { 95 int shift; 96 }; 97 98 #define LMK_SEED_SIZE 64 /* hash + 0 */ 99 struct iv_lmk_private { 100 struct crypto_shash *hash_tfm; 101 u8 *seed; 102 }; 103 104 #define TCW_WHITENING_SIZE 16 105 struct iv_tcw_private { 106 struct crypto_shash *crc32_tfm; 107 u8 *iv_seed; 108 u8 *whitening; 109 }; 110 111 /* 112 * Crypt: maps a linear range of a block device 113 * and encrypts / decrypts at the same time. 114 */ 115 enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID, 116 DM_CRYPT_SAME_CPU, DM_CRYPT_NO_OFFLOAD, 117 DM_CRYPT_EXIT_THREAD}; 118 119 /* 120 * The fields in here must be read only after initialization. 121 */ 122 struct crypt_config { 123 struct dm_dev *dev; 124 sector_t start; 125 126 /* 127 * pool for per bio private data, crypto requests and 128 * encryption requeusts/buffer pages 129 */ 130 mempool_t *req_pool; 131 mempool_t *page_pool; 132 struct bio_set *bs; 133 struct mutex bio_alloc_lock; 134 135 struct workqueue_struct *io_queue; 136 struct workqueue_struct *crypt_queue; 137 138 struct task_struct *write_thread; 139 wait_queue_head_t write_thread_wait; 140 struct rb_root write_tree; 141 142 char *cipher; 143 char *cipher_string; 144 145 struct crypt_iv_operations *iv_gen_ops; 146 union { 147 struct iv_essiv_private essiv; 148 struct iv_benbi_private benbi; 149 struct iv_lmk_private lmk; 150 struct iv_tcw_private tcw; 151 } iv_gen_private; 152 sector_t iv_offset; 153 unsigned int iv_size; 154 155 /* ESSIV: struct crypto_cipher *essiv_tfm */ 156 void *iv_private; 157 struct crypto_skcipher **tfms; 158 unsigned tfms_count; 159 160 /* 161 * Layout of each crypto request: 162 * 163 * struct skcipher_request 164 * context 165 * padding 166 * struct dm_crypt_request 167 * padding 168 * IV 169 * 170 * The padding is added so that dm_crypt_request and the IV are 171 * correctly aligned. 172 */ 173 unsigned int dmreq_start; 174 175 unsigned int per_bio_data_size; 176 177 unsigned long flags; 178 unsigned int key_size; 179 unsigned int key_parts; /* independent parts in key buffer */ 180 unsigned int key_extra_size; /* additional keys length */ 181 u8 key[0]; 182 }; 183 184 #define MIN_IOS 16 185 186 static void clone_init(struct dm_crypt_io *, struct bio *); 187 static void kcryptd_queue_crypt(struct dm_crypt_io *io); 188 static u8 *iv_of_dmreq(struct crypt_config *cc, struct dm_crypt_request *dmreq); 189 190 /* 191 * Use this to access cipher attributes that are the same for each CPU. 192 */ 193 static struct crypto_skcipher *any_tfm(struct crypt_config *cc) 194 { 195 return cc->tfms[0]; 196 } 197 198 /* 199 * Different IV generation algorithms: 200 * 201 * plain: the initial vector is the 32-bit little-endian version of the sector 202 * number, padded with zeros if necessary. 203 * 204 * plain64: the initial vector is the 64-bit little-endian version of the sector 205 * number, padded with zeros if necessary. 206 * 207 * essiv: "encrypted sector|salt initial vector", the sector number is 208 * encrypted with the bulk cipher using a salt as key. The salt 209 * should be derived from the bulk cipher's key via hashing. 210 * 211 * benbi: the 64-bit "big-endian 'narrow block'-count", starting at 1 212 * (needed for LRW-32-AES and possible other narrow block modes) 213 * 214 * null: the initial vector is always zero. Provides compatibility with 215 * obsolete loop_fish2 devices. Do not use for new devices. 216 * 217 * lmk: Compatible implementation of the block chaining mode used 218 * by the Loop-AES block device encryption system 219 * designed by Jari Ruusu. See http://loop-aes.sourceforge.net/ 220 * It operates on full 512 byte sectors and uses CBC 221 * with an IV derived from the sector number, the data and 222 * optionally extra IV seed. 223 * This means that after decryption the first block 224 * of sector must be tweaked according to decrypted data. 225 * Loop-AES can use three encryption schemes: 226 * version 1: is plain aes-cbc mode 227 * version 2: uses 64 multikey scheme with lmk IV generator 228 * version 3: the same as version 2 with additional IV seed 229 * (it uses 65 keys, last key is used as IV seed) 230 * 231 * tcw: Compatible implementation of the block chaining mode used 232 * by the TrueCrypt device encryption system (prior to version 4.1). 233 * For more info see: https://gitlab.com/cryptsetup/cryptsetup/wikis/TrueCryptOnDiskFormat 234 * It operates on full 512 byte sectors and uses CBC 235 * with an IV derived from initial key and the sector number. 236 * In addition, whitening value is applied on every sector, whitening 237 * is calculated from initial key, sector number and mixed using CRC32. 238 * Note that this encryption scheme is vulnerable to watermarking attacks 239 * and should be used for old compatible containers access only. 240 * 241 * plumb: unimplemented, see: 242 * http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454 243 */ 244 245 static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv, 246 struct dm_crypt_request *dmreq) 247 { 248 memset(iv, 0, cc->iv_size); 249 *(__le32 *)iv = cpu_to_le32(dmreq->iv_sector & 0xffffffff); 250 251 return 0; 252 } 253 254 static int crypt_iv_plain64_gen(struct crypt_config *cc, u8 *iv, 255 struct dm_crypt_request *dmreq) 256 { 257 memset(iv, 0, cc->iv_size); 258 *(__le64 *)iv = cpu_to_le64(dmreq->iv_sector); 259 260 return 0; 261 } 262 263 /* Initialise ESSIV - compute salt but no local memory allocations */ 264 static int crypt_iv_essiv_init(struct crypt_config *cc) 265 { 266 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv; 267 AHASH_REQUEST_ON_STACK(req, essiv->hash_tfm); 268 struct scatterlist sg; 269 struct crypto_cipher *essiv_tfm; 270 int err; 271 272 sg_init_one(&sg, cc->key, cc->key_size); 273 ahash_request_set_tfm(req, essiv->hash_tfm); 274 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL); 275 ahash_request_set_crypt(req, &sg, essiv->salt, cc->key_size); 276 277 err = crypto_ahash_digest(req); 278 ahash_request_zero(req); 279 if (err) 280 return err; 281 282 essiv_tfm = cc->iv_private; 283 284 err = crypto_cipher_setkey(essiv_tfm, essiv->salt, 285 crypto_ahash_digestsize(essiv->hash_tfm)); 286 if (err) 287 return err; 288 289 return 0; 290 } 291 292 /* Wipe salt and reset key derived from volume key */ 293 static int crypt_iv_essiv_wipe(struct crypt_config *cc) 294 { 295 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv; 296 unsigned salt_size = crypto_ahash_digestsize(essiv->hash_tfm); 297 struct crypto_cipher *essiv_tfm; 298 int r, err = 0; 299 300 memset(essiv->salt, 0, salt_size); 301 302 essiv_tfm = cc->iv_private; 303 r = crypto_cipher_setkey(essiv_tfm, essiv->salt, salt_size); 304 if (r) 305 err = r; 306 307 return err; 308 } 309 310 /* Set up per cpu cipher state */ 311 static struct crypto_cipher *setup_essiv_cpu(struct crypt_config *cc, 312 struct dm_target *ti, 313 u8 *salt, unsigned saltsize) 314 { 315 struct crypto_cipher *essiv_tfm; 316 int err; 317 318 /* Setup the essiv_tfm with the given salt */ 319 essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC); 320 if (IS_ERR(essiv_tfm)) { 321 ti->error = "Error allocating crypto tfm for ESSIV"; 322 return essiv_tfm; 323 } 324 325 if (crypto_cipher_blocksize(essiv_tfm) != 326 crypto_skcipher_ivsize(any_tfm(cc))) { 327 ti->error = "Block size of ESSIV cipher does " 328 "not match IV size of block cipher"; 329 crypto_free_cipher(essiv_tfm); 330 return ERR_PTR(-EINVAL); 331 } 332 333 err = crypto_cipher_setkey(essiv_tfm, salt, saltsize); 334 if (err) { 335 ti->error = "Failed to set key for ESSIV cipher"; 336 crypto_free_cipher(essiv_tfm); 337 return ERR_PTR(err); 338 } 339 340 return essiv_tfm; 341 } 342 343 static void crypt_iv_essiv_dtr(struct crypt_config *cc) 344 { 345 struct crypto_cipher *essiv_tfm; 346 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv; 347 348 crypto_free_ahash(essiv->hash_tfm); 349 essiv->hash_tfm = NULL; 350 351 kzfree(essiv->salt); 352 essiv->salt = NULL; 353 354 essiv_tfm = cc->iv_private; 355 356 if (essiv_tfm) 357 crypto_free_cipher(essiv_tfm); 358 359 cc->iv_private = NULL; 360 } 361 362 static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti, 363 const char *opts) 364 { 365 struct crypto_cipher *essiv_tfm = NULL; 366 struct crypto_ahash *hash_tfm = NULL; 367 u8 *salt = NULL; 368 int err; 369 370 if (!opts) { 371 ti->error = "Digest algorithm missing for ESSIV mode"; 372 return -EINVAL; 373 } 374 375 /* Allocate hash algorithm */ 376 hash_tfm = crypto_alloc_ahash(opts, 0, CRYPTO_ALG_ASYNC); 377 if (IS_ERR(hash_tfm)) { 378 ti->error = "Error initializing ESSIV hash"; 379 err = PTR_ERR(hash_tfm); 380 goto bad; 381 } 382 383 salt = kzalloc(crypto_ahash_digestsize(hash_tfm), GFP_KERNEL); 384 if (!salt) { 385 ti->error = "Error kmallocing salt storage in ESSIV"; 386 err = -ENOMEM; 387 goto bad; 388 } 389 390 cc->iv_gen_private.essiv.salt = salt; 391 cc->iv_gen_private.essiv.hash_tfm = hash_tfm; 392 393 essiv_tfm = setup_essiv_cpu(cc, ti, salt, 394 crypto_ahash_digestsize(hash_tfm)); 395 if (IS_ERR(essiv_tfm)) { 396 crypt_iv_essiv_dtr(cc); 397 return PTR_ERR(essiv_tfm); 398 } 399 cc->iv_private = essiv_tfm; 400 401 return 0; 402 403 bad: 404 if (hash_tfm && !IS_ERR(hash_tfm)) 405 crypto_free_ahash(hash_tfm); 406 kfree(salt); 407 return err; 408 } 409 410 static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv, 411 struct dm_crypt_request *dmreq) 412 { 413 struct crypto_cipher *essiv_tfm = cc->iv_private; 414 415 memset(iv, 0, cc->iv_size); 416 *(__le64 *)iv = cpu_to_le64(dmreq->iv_sector); 417 crypto_cipher_encrypt_one(essiv_tfm, iv, iv); 418 419 return 0; 420 } 421 422 static int crypt_iv_benbi_ctr(struct crypt_config *cc, struct dm_target *ti, 423 const char *opts) 424 { 425 unsigned bs = crypto_skcipher_blocksize(any_tfm(cc)); 426 int log = ilog2(bs); 427 428 /* we need to calculate how far we must shift the sector count 429 * to get the cipher block count, we use this shift in _gen */ 430 431 if (1 << log != bs) { 432 ti->error = "cypher blocksize is not a power of 2"; 433 return -EINVAL; 434 } 435 436 if (log > 9) { 437 ti->error = "cypher blocksize is > 512"; 438 return -EINVAL; 439 } 440 441 cc->iv_gen_private.benbi.shift = 9 - log; 442 443 return 0; 444 } 445 446 static void crypt_iv_benbi_dtr(struct crypt_config *cc) 447 { 448 } 449 450 static int crypt_iv_benbi_gen(struct crypt_config *cc, u8 *iv, 451 struct dm_crypt_request *dmreq) 452 { 453 __be64 val; 454 455 memset(iv, 0, cc->iv_size - sizeof(u64)); /* rest is cleared below */ 456 457 val = cpu_to_be64(((u64)dmreq->iv_sector << cc->iv_gen_private.benbi.shift) + 1); 458 put_unaligned(val, (__be64 *)(iv + cc->iv_size - sizeof(u64))); 459 460 return 0; 461 } 462 463 static int crypt_iv_null_gen(struct crypt_config *cc, u8 *iv, 464 struct dm_crypt_request *dmreq) 465 { 466 memset(iv, 0, cc->iv_size); 467 468 return 0; 469 } 470 471 static void crypt_iv_lmk_dtr(struct crypt_config *cc) 472 { 473 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk; 474 475 if (lmk->hash_tfm && !IS_ERR(lmk->hash_tfm)) 476 crypto_free_shash(lmk->hash_tfm); 477 lmk->hash_tfm = NULL; 478 479 kzfree(lmk->seed); 480 lmk->seed = NULL; 481 } 482 483 static int crypt_iv_lmk_ctr(struct crypt_config *cc, struct dm_target *ti, 484 const char *opts) 485 { 486 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk; 487 488 lmk->hash_tfm = crypto_alloc_shash("md5", 0, 0); 489 if (IS_ERR(lmk->hash_tfm)) { 490 ti->error = "Error initializing LMK hash"; 491 return PTR_ERR(lmk->hash_tfm); 492 } 493 494 /* No seed in LMK version 2 */ 495 if (cc->key_parts == cc->tfms_count) { 496 lmk->seed = NULL; 497 return 0; 498 } 499 500 lmk->seed = kzalloc(LMK_SEED_SIZE, GFP_KERNEL); 501 if (!lmk->seed) { 502 crypt_iv_lmk_dtr(cc); 503 ti->error = "Error kmallocing seed storage in LMK"; 504 return -ENOMEM; 505 } 506 507 return 0; 508 } 509 510 static int crypt_iv_lmk_init(struct crypt_config *cc) 511 { 512 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk; 513 int subkey_size = cc->key_size / cc->key_parts; 514 515 /* LMK seed is on the position of LMK_KEYS + 1 key */ 516 if (lmk->seed) 517 memcpy(lmk->seed, cc->key + (cc->tfms_count * subkey_size), 518 crypto_shash_digestsize(lmk->hash_tfm)); 519 520 return 0; 521 } 522 523 static int crypt_iv_lmk_wipe(struct crypt_config *cc) 524 { 525 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk; 526 527 if (lmk->seed) 528 memset(lmk->seed, 0, LMK_SEED_SIZE); 529 530 return 0; 531 } 532 533 static int crypt_iv_lmk_one(struct crypt_config *cc, u8 *iv, 534 struct dm_crypt_request *dmreq, 535 u8 *data) 536 { 537 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk; 538 SHASH_DESC_ON_STACK(desc, lmk->hash_tfm); 539 struct md5_state md5state; 540 __le32 buf[4]; 541 int i, r; 542 543 desc->tfm = lmk->hash_tfm; 544 desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; 545 546 r = crypto_shash_init(desc); 547 if (r) 548 return r; 549 550 if (lmk->seed) { 551 r = crypto_shash_update(desc, lmk->seed, LMK_SEED_SIZE); 552 if (r) 553 return r; 554 } 555 556 /* Sector is always 512B, block size 16, add data of blocks 1-31 */ 557 r = crypto_shash_update(desc, data + 16, 16 * 31); 558 if (r) 559 return r; 560 561 /* Sector is cropped to 56 bits here */ 562 buf[0] = cpu_to_le32(dmreq->iv_sector & 0xFFFFFFFF); 563 buf[1] = cpu_to_le32((((u64)dmreq->iv_sector >> 32) & 0x00FFFFFF) | 0x80000000); 564 buf[2] = cpu_to_le32(4024); 565 buf[3] = 0; 566 r = crypto_shash_update(desc, (u8 *)buf, sizeof(buf)); 567 if (r) 568 return r; 569 570 /* No MD5 padding here */ 571 r = crypto_shash_export(desc, &md5state); 572 if (r) 573 return r; 574 575 for (i = 0; i < MD5_HASH_WORDS; i++) 576 __cpu_to_le32s(&md5state.hash[i]); 577 memcpy(iv, &md5state.hash, cc->iv_size); 578 579 return 0; 580 } 581 582 static int crypt_iv_lmk_gen(struct crypt_config *cc, u8 *iv, 583 struct dm_crypt_request *dmreq) 584 { 585 u8 *src; 586 int r = 0; 587 588 if (bio_data_dir(dmreq->ctx->bio_in) == WRITE) { 589 src = kmap_atomic(sg_page(&dmreq->sg_in)); 590 r = crypt_iv_lmk_one(cc, iv, dmreq, src + dmreq->sg_in.offset); 591 kunmap_atomic(src); 592 } else 593 memset(iv, 0, cc->iv_size); 594 595 return r; 596 } 597 598 static int crypt_iv_lmk_post(struct crypt_config *cc, u8 *iv, 599 struct dm_crypt_request *dmreq) 600 { 601 u8 *dst; 602 int r; 603 604 if (bio_data_dir(dmreq->ctx->bio_in) == WRITE) 605 return 0; 606 607 dst = kmap_atomic(sg_page(&dmreq->sg_out)); 608 r = crypt_iv_lmk_one(cc, iv, dmreq, dst + dmreq->sg_out.offset); 609 610 /* Tweak the first block of plaintext sector */ 611 if (!r) 612 crypto_xor(dst + dmreq->sg_out.offset, iv, cc->iv_size); 613 614 kunmap_atomic(dst); 615 return r; 616 } 617 618 static void crypt_iv_tcw_dtr(struct crypt_config *cc) 619 { 620 struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw; 621 622 kzfree(tcw->iv_seed); 623 tcw->iv_seed = NULL; 624 kzfree(tcw->whitening); 625 tcw->whitening = NULL; 626 627 if (tcw->crc32_tfm && !IS_ERR(tcw->crc32_tfm)) 628 crypto_free_shash(tcw->crc32_tfm); 629 tcw->crc32_tfm = NULL; 630 } 631 632 static int crypt_iv_tcw_ctr(struct crypt_config *cc, struct dm_target *ti, 633 const char *opts) 634 { 635 struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw; 636 637 if (cc->key_size <= (cc->iv_size + TCW_WHITENING_SIZE)) { 638 ti->error = "Wrong key size for TCW"; 639 return -EINVAL; 640 } 641 642 tcw->crc32_tfm = crypto_alloc_shash("crc32", 0, 0); 643 if (IS_ERR(tcw->crc32_tfm)) { 644 ti->error = "Error initializing CRC32 in TCW"; 645 return PTR_ERR(tcw->crc32_tfm); 646 } 647 648 tcw->iv_seed = kzalloc(cc->iv_size, GFP_KERNEL); 649 tcw->whitening = kzalloc(TCW_WHITENING_SIZE, GFP_KERNEL); 650 if (!tcw->iv_seed || !tcw->whitening) { 651 crypt_iv_tcw_dtr(cc); 652 ti->error = "Error allocating seed storage in TCW"; 653 return -ENOMEM; 654 } 655 656 return 0; 657 } 658 659 static int crypt_iv_tcw_init(struct crypt_config *cc) 660 { 661 struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw; 662 int key_offset = cc->key_size - cc->iv_size - TCW_WHITENING_SIZE; 663 664 memcpy(tcw->iv_seed, &cc->key[key_offset], cc->iv_size); 665 memcpy(tcw->whitening, &cc->key[key_offset + cc->iv_size], 666 TCW_WHITENING_SIZE); 667 668 return 0; 669 } 670 671 static int crypt_iv_tcw_wipe(struct crypt_config *cc) 672 { 673 struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw; 674 675 memset(tcw->iv_seed, 0, cc->iv_size); 676 memset(tcw->whitening, 0, TCW_WHITENING_SIZE); 677 678 return 0; 679 } 680 681 static int crypt_iv_tcw_whitening(struct crypt_config *cc, 682 struct dm_crypt_request *dmreq, 683 u8 *data) 684 { 685 struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw; 686 u64 sector = cpu_to_le64((u64)dmreq->iv_sector); 687 u8 buf[TCW_WHITENING_SIZE]; 688 SHASH_DESC_ON_STACK(desc, tcw->crc32_tfm); 689 int i, r; 690 691 /* xor whitening with sector number */ 692 memcpy(buf, tcw->whitening, TCW_WHITENING_SIZE); 693 crypto_xor(buf, (u8 *)§or, 8); 694 crypto_xor(&buf[8], (u8 *)§or, 8); 695 696 /* calculate crc32 for every 32bit part and xor it */ 697 desc->tfm = tcw->crc32_tfm; 698 desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; 699 for (i = 0; i < 4; i++) { 700 r = crypto_shash_init(desc); 701 if (r) 702 goto out; 703 r = crypto_shash_update(desc, &buf[i * 4], 4); 704 if (r) 705 goto out; 706 r = crypto_shash_final(desc, &buf[i * 4]); 707 if (r) 708 goto out; 709 } 710 crypto_xor(&buf[0], &buf[12], 4); 711 crypto_xor(&buf[4], &buf[8], 4); 712 713 /* apply whitening (8 bytes) to whole sector */ 714 for (i = 0; i < ((1 << SECTOR_SHIFT) / 8); i++) 715 crypto_xor(data + i * 8, buf, 8); 716 out: 717 memzero_explicit(buf, sizeof(buf)); 718 return r; 719 } 720 721 static int crypt_iv_tcw_gen(struct crypt_config *cc, u8 *iv, 722 struct dm_crypt_request *dmreq) 723 { 724 struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw; 725 u64 sector = cpu_to_le64((u64)dmreq->iv_sector); 726 u8 *src; 727 int r = 0; 728 729 /* Remove whitening from ciphertext */ 730 if (bio_data_dir(dmreq->ctx->bio_in) != WRITE) { 731 src = kmap_atomic(sg_page(&dmreq->sg_in)); 732 r = crypt_iv_tcw_whitening(cc, dmreq, src + dmreq->sg_in.offset); 733 kunmap_atomic(src); 734 } 735 736 /* Calculate IV */ 737 memcpy(iv, tcw->iv_seed, cc->iv_size); 738 crypto_xor(iv, (u8 *)§or, 8); 739 if (cc->iv_size > 8) 740 crypto_xor(&iv[8], (u8 *)§or, cc->iv_size - 8); 741 742 return r; 743 } 744 745 static int crypt_iv_tcw_post(struct crypt_config *cc, u8 *iv, 746 struct dm_crypt_request *dmreq) 747 { 748 u8 *dst; 749 int r; 750 751 if (bio_data_dir(dmreq->ctx->bio_in) != WRITE) 752 return 0; 753 754 /* Apply whitening on ciphertext */ 755 dst = kmap_atomic(sg_page(&dmreq->sg_out)); 756 r = crypt_iv_tcw_whitening(cc, dmreq, dst + dmreq->sg_out.offset); 757 kunmap_atomic(dst); 758 759 return r; 760 } 761 762 static struct crypt_iv_operations crypt_iv_plain_ops = { 763 .generator = crypt_iv_plain_gen 764 }; 765 766 static struct crypt_iv_operations crypt_iv_plain64_ops = { 767 .generator = crypt_iv_plain64_gen 768 }; 769 770 static struct crypt_iv_operations crypt_iv_essiv_ops = { 771 .ctr = crypt_iv_essiv_ctr, 772 .dtr = crypt_iv_essiv_dtr, 773 .init = crypt_iv_essiv_init, 774 .wipe = crypt_iv_essiv_wipe, 775 .generator = crypt_iv_essiv_gen 776 }; 777 778 static struct crypt_iv_operations crypt_iv_benbi_ops = { 779 .ctr = crypt_iv_benbi_ctr, 780 .dtr = crypt_iv_benbi_dtr, 781 .generator = crypt_iv_benbi_gen 782 }; 783 784 static struct crypt_iv_operations crypt_iv_null_ops = { 785 .generator = crypt_iv_null_gen 786 }; 787 788 static struct crypt_iv_operations crypt_iv_lmk_ops = { 789 .ctr = crypt_iv_lmk_ctr, 790 .dtr = crypt_iv_lmk_dtr, 791 .init = crypt_iv_lmk_init, 792 .wipe = crypt_iv_lmk_wipe, 793 .generator = crypt_iv_lmk_gen, 794 .post = crypt_iv_lmk_post 795 }; 796 797 static struct crypt_iv_operations crypt_iv_tcw_ops = { 798 .ctr = crypt_iv_tcw_ctr, 799 .dtr = crypt_iv_tcw_dtr, 800 .init = crypt_iv_tcw_init, 801 .wipe = crypt_iv_tcw_wipe, 802 .generator = crypt_iv_tcw_gen, 803 .post = crypt_iv_tcw_post 804 }; 805 806 static void crypt_convert_init(struct crypt_config *cc, 807 struct convert_context *ctx, 808 struct bio *bio_out, struct bio *bio_in, 809 sector_t sector) 810 { 811 ctx->bio_in = bio_in; 812 ctx->bio_out = bio_out; 813 if (bio_in) 814 ctx->iter_in = bio_in->bi_iter; 815 if (bio_out) 816 ctx->iter_out = bio_out->bi_iter; 817 ctx->cc_sector = sector + cc->iv_offset; 818 init_completion(&ctx->restart); 819 } 820 821 static struct dm_crypt_request *dmreq_of_req(struct crypt_config *cc, 822 struct skcipher_request *req) 823 { 824 return (struct dm_crypt_request *)((char *)req + cc->dmreq_start); 825 } 826 827 static struct skcipher_request *req_of_dmreq(struct crypt_config *cc, 828 struct dm_crypt_request *dmreq) 829 { 830 return (struct skcipher_request *)((char *)dmreq - cc->dmreq_start); 831 } 832 833 static u8 *iv_of_dmreq(struct crypt_config *cc, 834 struct dm_crypt_request *dmreq) 835 { 836 return (u8 *)ALIGN((unsigned long)(dmreq + 1), 837 crypto_skcipher_alignmask(any_tfm(cc)) + 1); 838 } 839 840 static int crypt_convert_block(struct crypt_config *cc, 841 struct convert_context *ctx, 842 struct skcipher_request *req) 843 { 844 struct bio_vec bv_in = bio_iter_iovec(ctx->bio_in, ctx->iter_in); 845 struct bio_vec bv_out = bio_iter_iovec(ctx->bio_out, ctx->iter_out); 846 struct dm_crypt_request *dmreq; 847 u8 *iv; 848 int r; 849 850 dmreq = dmreq_of_req(cc, req); 851 iv = iv_of_dmreq(cc, dmreq); 852 853 dmreq->iv_sector = ctx->cc_sector; 854 dmreq->ctx = ctx; 855 sg_init_table(&dmreq->sg_in, 1); 856 sg_set_page(&dmreq->sg_in, bv_in.bv_page, 1 << SECTOR_SHIFT, 857 bv_in.bv_offset); 858 859 sg_init_table(&dmreq->sg_out, 1); 860 sg_set_page(&dmreq->sg_out, bv_out.bv_page, 1 << SECTOR_SHIFT, 861 bv_out.bv_offset); 862 863 bio_advance_iter(ctx->bio_in, &ctx->iter_in, 1 << SECTOR_SHIFT); 864 bio_advance_iter(ctx->bio_out, &ctx->iter_out, 1 << SECTOR_SHIFT); 865 866 if (cc->iv_gen_ops) { 867 r = cc->iv_gen_ops->generator(cc, iv, dmreq); 868 if (r < 0) 869 return r; 870 } 871 872 skcipher_request_set_crypt(req, &dmreq->sg_in, &dmreq->sg_out, 873 1 << SECTOR_SHIFT, iv); 874 875 if (bio_data_dir(ctx->bio_in) == WRITE) 876 r = crypto_skcipher_encrypt(req); 877 else 878 r = crypto_skcipher_decrypt(req); 879 880 if (!r && cc->iv_gen_ops && cc->iv_gen_ops->post) 881 r = cc->iv_gen_ops->post(cc, iv, dmreq); 882 883 return r; 884 } 885 886 static void kcryptd_async_done(struct crypto_async_request *async_req, 887 int error); 888 889 static void crypt_alloc_req(struct crypt_config *cc, 890 struct convert_context *ctx) 891 { 892 unsigned key_index = ctx->cc_sector & (cc->tfms_count - 1); 893 894 if (!ctx->req) 895 ctx->req = mempool_alloc(cc->req_pool, GFP_NOIO); 896 897 skcipher_request_set_tfm(ctx->req, cc->tfms[key_index]); 898 899 /* 900 * Use REQ_MAY_BACKLOG so a cipher driver internally backlogs 901 * requests if driver request queue is full. 902 */ 903 skcipher_request_set_callback(ctx->req, 904 CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, 905 kcryptd_async_done, dmreq_of_req(cc, ctx->req)); 906 } 907 908 static void crypt_free_req(struct crypt_config *cc, 909 struct skcipher_request *req, struct bio *base_bio) 910 { 911 struct dm_crypt_io *io = dm_per_bio_data(base_bio, cc->per_bio_data_size); 912 913 if ((struct skcipher_request *)(io + 1) != req) 914 mempool_free(req, cc->req_pool); 915 } 916 917 /* 918 * Encrypt / decrypt data from one bio to another one (can be the same one) 919 */ 920 static int crypt_convert(struct crypt_config *cc, 921 struct convert_context *ctx) 922 { 923 int r; 924 925 atomic_set(&ctx->cc_pending, 1); 926 927 while (ctx->iter_in.bi_size && ctx->iter_out.bi_size) { 928 929 crypt_alloc_req(cc, ctx); 930 931 atomic_inc(&ctx->cc_pending); 932 933 r = crypt_convert_block(cc, ctx, ctx->req); 934 935 switch (r) { 936 /* 937 * The request was queued by a crypto driver 938 * but the driver request queue is full, let's wait. 939 */ 940 case -EBUSY: 941 wait_for_completion(&ctx->restart); 942 reinit_completion(&ctx->restart); 943 /* fall through */ 944 /* 945 * The request is queued and processed asynchronously, 946 * completion function kcryptd_async_done() will be called. 947 */ 948 case -EINPROGRESS: 949 ctx->req = NULL; 950 ctx->cc_sector++; 951 continue; 952 /* 953 * The request was already processed (synchronously). 954 */ 955 case 0: 956 atomic_dec(&ctx->cc_pending); 957 ctx->cc_sector++; 958 cond_resched(); 959 continue; 960 961 /* There was an error while processing the request. */ 962 default: 963 atomic_dec(&ctx->cc_pending); 964 return r; 965 } 966 } 967 968 return 0; 969 } 970 971 static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone); 972 973 /* 974 * Generate a new unfragmented bio with the given size 975 * This should never violate the device limitations (but only because 976 * max_segment_size is being constrained to PAGE_SIZE). 977 * 978 * This function may be called concurrently. If we allocate from the mempool 979 * concurrently, there is a possibility of deadlock. For example, if we have 980 * mempool of 256 pages, two processes, each wanting 256, pages allocate from 981 * the mempool concurrently, it may deadlock in a situation where both processes 982 * have allocated 128 pages and the mempool is exhausted. 983 * 984 * In order to avoid this scenario we allocate the pages under a mutex. 985 * 986 * In order to not degrade performance with excessive locking, we try 987 * non-blocking allocations without a mutex first but on failure we fallback 988 * to blocking allocations with a mutex. 989 */ 990 static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size) 991 { 992 struct crypt_config *cc = io->cc; 993 struct bio *clone; 994 unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; 995 gfp_t gfp_mask = GFP_NOWAIT | __GFP_HIGHMEM; 996 unsigned i, len, remaining_size; 997 struct page *page; 998 struct bio_vec *bvec; 999 1000 retry: 1001 if (unlikely(gfp_mask & __GFP_DIRECT_RECLAIM)) 1002 mutex_lock(&cc->bio_alloc_lock); 1003 1004 clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs); 1005 if (!clone) 1006 goto return_clone; 1007 1008 clone_init(io, clone); 1009 1010 remaining_size = size; 1011 1012 for (i = 0; i < nr_iovecs; i++) { 1013 page = mempool_alloc(cc->page_pool, gfp_mask); 1014 if (!page) { 1015 crypt_free_buffer_pages(cc, clone); 1016 bio_put(clone); 1017 gfp_mask |= __GFP_DIRECT_RECLAIM; 1018 goto retry; 1019 } 1020 1021 len = (remaining_size > PAGE_SIZE) ? PAGE_SIZE : remaining_size; 1022 1023 bvec = &clone->bi_io_vec[clone->bi_vcnt++]; 1024 bvec->bv_page = page; 1025 bvec->bv_len = len; 1026 bvec->bv_offset = 0; 1027 1028 clone->bi_iter.bi_size += len; 1029 1030 remaining_size -= len; 1031 } 1032 1033 return_clone: 1034 if (unlikely(gfp_mask & __GFP_DIRECT_RECLAIM)) 1035 mutex_unlock(&cc->bio_alloc_lock); 1036 1037 return clone; 1038 } 1039 1040 static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone) 1041 { 1042 unsigned int i; 1043 struct bio_vec *bv; 1044 1045 bio_for_each_segment_all(bv, clone, i) { 1046 BUG_ON(!bv->bv_page); 1047 mempool_free(bv->bv_page, cc->page_pool); 1048 bv->bv_page = NULL; 1049 } 1050 } 1051 1052 static void crypt_io_init(struct dm_crypt_io *io, struct crypt_config *cc, 1053 struct bio *bio, sector_t sector) 1054 { 1055 io->cc = cc; 1056 io->base_bio = bio; 1057 io->sector = sector; 1058 io->error = 0; 1059 io->ctx.req = NULL; 1060 atomic_set(&io->io_pending, 0); 1061 } 1062 1063 static void crypt_inc_pending(struct dm_crypt_io *io) 1064 { 1065 atomic_inc(&io->io_pending); 1066 } 1067 1068 /* 1069 * One of the bios was finished. Check for completion of 1070 * the whole request and correctly clean up the buffer. 1071 */ 1072 static void crypt_dec_pending(struct dm_crypt_io *io) 1073 { 1074 struct crypt_config *cc = io->cc; 1075 struct bio *base_bio = io->base_bio; 1076 int error = io->error; 1077 1078 if (!atomic_dec_and_test(&io->io_pending)) 1079 return; 1080 1081 if (io->ctx.req) 1082 crypt_free_req(cc, io->ctx.req, base_bio); 1083 1084 base_bio->bi_error = error; 1085 bio_endio(base_bio); 1086 } 1087 1088 /* 1089 * kcryptd/kcryptd_io: 1090 * 1091 * Needed because it would be very unwise to do decryption in an 1092 * interrupt context. 1093 * 1094 * kcryptd performs the actual encryption or decryption. 1095 * 1096 * kcryptd_io performs the IO submission. 1097 * 1098 * They must be separated as otherwise the final stages could be 1099 * starved by new requests which can block in the first stages due 1100 * to memory allocation. 1101 * 1102 * The work is done per CPU global for all dm-crypt instances. 1103 * They should not depend on each other and do not block. 1104 */ 1105 static void crypt_endio(struct bio *clone) 1106 { 1107 struct dm_crypt_io *io = clone->bi_private; 1108 struct crypt_config *cc = io->cc; 1109 unsigned rw = bio_data_dir(clone); 1110 int error; 1111 1112 /* 1113 * free the processed pages 1114 */ 1115 if (rw == WRITE) 1116 crypt_free_buffer_pages(cc, clone); 1117 1118 error = clone->bi_error; 1119 bio_put(clone); 1120 1121 if (rw == READ && !error) { 1122 kcryptd_queue_crypt(io); 1123 return; 1124 } 1125 1126 if (unlikely(error)) 1127 io->error = error; 1128 1129 crypt_dec_pending(io); 1130 } 1131 1132 static void clone_init(struct dm_crypt_io *io, struct bio *clone) 1133 { 1134 struct crypt_config *cc = io->cc; 1135 1136 clone->bi_private = io; 1137 clone->bi_end_io = crypt_endio; 1138 clone->bi_bdev = cc->dev->bdev; 1139 clone->bi_rw = io->base_bio->bi_rw; 1140 } 1141 1142 static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp) 1143 { 1144 struct crypt_config *cc = io->cc; 1145 struct bio *clone; 1146 1147 /* 1148 * We need the original biovec array in order to decrypt 1149 * the whole bio data *afterwards* -- thanks to immutable 1150 * biovecs we don't need to worry about the block layer 1151 * modifying the biovec array; so leverage bio_clone_fast(). 1152 */ 1153 clone = bio_clone_fast(io->base_bio, gfp, cc->bs); 1154 if (!clone) 1155 return 1; 1156 1157 crypt_inc_pending(io); 1158 1159 clone_init(io, clone); 1160 clone->bi_iter.bi_sector = cc->start + io->sector; 1161 1162 generic_make_request(clone); 1163 return 0; 1164 } 1165 1166 static void kcryptd_io_read_work(struct work_struct *work) 1167 { 1168 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work); 1169 1170 crypt_inc_pending(io); 1171 if (kcryptd_io_read(io, GFP_NOIO)) 1172 io->error = -ENOMEM; 1173 crypt_dec_pending(io); 1174 } 1175 1176 static void kcryptd_queue_read(struct dm_crypt_io *io) 1177 { 1178 struct crypt_config *cc = io->cc; 1179 1180 INIT_WORK(&io->work, kcryptd_io_read_work); 1181 queue_work(cc->io_queue, &io->work); 1182 } 1183 1184 static void kcryptd_io_write(struct dm_crypt_io *io) 1185 { 1186 struct bio *clone = io->ctx.bio_out; 1187 1188 generic_make_request(clone); 1189 } 1190 1191 #define crypt_io_from_node(node) rb_entry((node), struct dm_crypt_io, rb_node) 1192 1193 static int dmcrypt_write(void *data) 1194 { 1195 struct crypt_config *cc = data; 1196 struct dm_crypt_io *io; 1197 1198 while (1) { 1199 struct rb_root write_tree; 1200 struct blk_plug plug; 1201 1202 DECLARE_WAITQUEUE(wait, current); 1203 1204 spin_lock_irq(&cc->write_thread_wait.lock); 1205 continue_locked: 1206 1207 if (!RB_EMPTY_ROOT(&cc->write_tree)) 1208 goto pop_from_list; 1209 1210 if (unlikely(test_bit(DM_CRYPT_EXIT_THREAD, &cc->flags))) { 1211 spin_unlock_irq(&cc->write_thread_wait.lock); 1212 break; 1213 } 1214 1215 __set_current_state(TASK_INTERRUPTIBLE); 1216 __add_wait_queue(&cc->write_thread_wait, &wait); 1217 1218 spin_unlock_irq(&cc->write_thread_wait.lock); 1219 1220 schedule(); 1221 1222 spin_lock_irq(&cc->write_thread_wait.lock); 1223 __remove_wait_queue(&cc->write_thread_wait, &wait); 1224 goto continue_locked; 1225 1226 pop_from_list: 1227 write_tree = cc->write_tree; 1228 cc->write_tree = RB_ROOT; 1229 spin_unlock_irq(&cc->write_thread_wait.lock); 1230 1231 BUG_ON(rb_parent(write_tree.rb_node)); 1232 1233 /* 1234 * Note: we cannot walk the tree here with rb_next because 1235 * the structures may be freed when kcryptd_io_write is called. 1236 */ 1237 blk_start_plug(&plug); 1238 do { 1239 io = crypt_io_from_node(rb_first(&write_tree)); 1240 rb_erase(&io->rb_node, &write_tree); 1241 kcryptd_io_write(io); 1242 } while (!RB_EMPTY_ROOT(&write_tree)); 1243 blk_finish_plug(&plug); 1244 } 1245 return 0; 1246 } 1247 1248 static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io, int async) 1249 { 1250 struct bio *clone = io->ctx.bio_out; 1251 struct crypt_config *cc = io->cc; 1252 unsigned long flags; 1253 sector_t sector; 1254 struct rb_node **rbp, *parent; 1255 1256 if (unlikely(io->error < 0)) { 1257 crypt_free_buffer_pages(cc, clone); 1258 bio_put(clone); 1259 crypt_dec_pending(io); 1260 return; 1261 } 1262 1263 /* crypt_convert should have filled the clone bio */ 1264 BUG_ON(io->ctx.iter_out.bi_size); 1265 1266 clone->bi_iter.bi_sector = cc->start + io->sector; 1267 1268 if (likely(!async) && test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags)) { 1269 generic_make_request(clone); 1270 return; 1271 } 1272 1273 spin_lock_irqsave(&cc->write_thread_wait.lock, flags); 1274 rbp = &cc->write_tree.rb_node; 1275 parent = NULL; 1276 sector = io->sector; 1277 while (*rbp) { 1278 parent = *rbp; 1279 if (sector < crypt_io_from_node(parent)->sector) 1280 rbp = &(*rbp)->rb_left; 1281 else 1282 rbp = &(*rbp)->rb_right; 1283 } 1284 rb_link_node(&io->rb_node, parent, rbp); 1285 rb_insert_color(&io->rb_node, &cc->write_tree); 1286 1287 wake_up_locked(&cc->write_thread_wait); 1288 spin_unlock_irqrestore(&cc->write_thread_wait.lock, flags); 1289 } 1290 1291 static void kcryptd_crypt_write_convert(struct dm_crypt_io *io) 1292 { 1293 struct crypt_config *cc = io->cc; 1294 struct bio *clone; 1295 int crypt_finished; 1296 sector_t sector = io->sector; 1297 int r; 1298 1299 /* 1300 * Prevent io from disappearing until this function completes. 1301 */ 1302 crypt_inc_pending(io); 1303 crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, sector); 1304 1305 clone = crypt_alloc_buffer(io, io->base_bio->bi_iter.bi_size); 1306 if (unlikely(!clone)) { 1307 io->error = -EIO; 1308 goto dec; 1309 } 1310 1311 io->ctx.bio_out = clone; 1312 io->ctx.iter_out = clone->bi_iter; 1313 1314 sector += bio_sectors(clone); 1315 1316 crypt_inc_pending(io); 1317 r = crypt_convert(cc, &io->ctx); 1318 if (r) 1319 io->error = -EIO; 1320 crypt_finished = atomic_dec_and_test(&io->ctx.cc_pending); 1321 1322 /* Encryption was already finished, submit io now */ 1323 if (crypt_finished) { 1324 kcryptd_crypt_write_io_submit(io, 0); 1325 io->sector = sector; 1326 } 1327 1328 dec: 1329 crypt_dec_pending(io); 1330 } 1331 1332 static void kcryptd_crypt_read_done(struct dm_crypt_io *io) 1333 { 1334 crypt_dec_pending(io); 1335 } 1336 1337 static void kcryptd_crypt_read_convert(struct dm_crypt_io *io) 1338 { 1339 struct crypt_config *cc = io->cc; 1340 int r = 0; 1341 1342 crypt_inc_pending(io); 1343 1344 crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio, 1345 io->sector); 1346 1347 r = crypt_convert(cc, &io->ctx); 1348 if (r < 0) 1349 io->error = -EIO; 1350 1351 if (atomic_dec_and_test(&io->ctx.cc_pending)) 1352 kcryptd_crypt_read_done(io); 1353 1354 crypt_dec_pending(io); 1355 } 1356 1357 static void kcryptd_async_done(struct crypto_async_request *async_req, 1358 int error) 1359 { 1360 struct dm_crypt_request *dmreq = async_req->data; 1361 struct convert_context *ctx = dmreq->ctx; 1362 struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx); 1363 struct crypt_config *cc = io->cc; 1364 1365 /* 1366 * A request from crypto driver backlog is going to be processed now, 1367 * finish the completion and continue in crypt_convert(). 1368 * (Callback will be called for the second time for this request.) 1369 */ 1370 if (error == -EINPROGRESS) { 1371 complete(&ctx->restart); 1372 return; 1373 } 1374 1375 if (!error && cc->iv_gen_ops && cc->iv_gen_ops->post) 1376 error = cc->iv_gen_ops->post(cc, iv_of_dmreq(cc, dmreq), dmreq); 1377 1378 if (error < 0) 1379 io->error = -EIO; 1380 1381 crypt_free_req(cc, req_of_dmreq(cc, dmreq), io->base_bio); 1382 1383 if (!atomic_dec_and_test(&ctx->cc_pending)) 1384 return; 1385 1386 if (bio_data_dir(io->base_bio) == READ) 1387 kcryptd_crypt_read_done(io); 1388 else 1389 kcryptd_crypt_write_io_submit(io, 1); 1390 } 1391 1392 static void kcryptd_crypt(struct work_struct *work) 1393 { 1394 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work); 1395 1396 if (bio_data_dir(io->base_bio) == READ) 1397 kcryptd_crypt_read_convert(io); 1398 else 1399 kcryptd_crypt_write_convert(io); 1400 } 1401 1402 static void kcryptd_queue_crypt(struct dm_crypt_io *io) 1403 { 1404 struct crypt_config *cc = io->cc; 1405 1406 INIT_WORK(&io->work, kcryptd_crypt); 1407 queue_work(cc->crypt_queue, &io->work); 1408 } 1409 1410 /* 1411 * Decode key from its hex representation 1412 */ 1413 static int crypt_decode_key(u8 *key, char *hex, unsigned int size) 1414 { 1415 char buffer[3]; 1416 unsigned int i; 1417 1418 buffer[2] = '\0'; 1419 1420 for (i = 0; i < size; i++) { 1421 buffer[0] = *hex++; 1422 buffer[1] = *hex++; 1423 1424 if (kstrtou8(buffer, 16, &key[i])) 1425 return -EINVAL; 1426 } 1427 1428 if (*hex != '\0') 1429 return -EINVAL; 1430 1431 return 0; 1432 } 1433 1434 static void crypt_free_tfms(struct crypt_config *cc) 1435 { 1436 unsigned i; 1437 1438 if (!cc->tfms) 1439 return; 1440 1441 for (i = 0; i < cc->tfms_count; i++) 1442 if (cc->tfms[i] && !IS_ERR(cc->tfms[i])) { 1443 crypto_free_skcipher(cc->tfms[i]); 1444 cc->tfms[i] = NULL; 1445 } 1446 1447 kfree(cc->tfms); 1448 cc->tfms = NULL; 1449 } 1450 1451 static int crypt_alloc_tfms(struct crypt_config *cc, char *ciphermode) 1452 { 1453 unsigned i; 1454 int err; 1455 1456 cc->tfms = kmalloc(cc->tfms_count * sizeof(struct crypto_skcipher *), 1457 GFP_KERNEL); 1458 if (!cc->tfms) 1459 return -ENOMEM; 1460 1461 for (i = 0; i < cc->tfms_count; i++) { 1462 cc->tfms[i] = crypto_alloc_skcipher(ciphermode, 0, 0); 1463 if (IS_ERR(cc->tfms[i])) { 1464 err = PTR_ERR(cc->tfms[i]); 1465 crypt_free_tfms(cc); 1466 return err; 1467 } 1468 } 1469 1470 return 0; 1471 } 1472 1473 static int crypt_setkey_allcpus(struct crypt_config *cc) 1474 { 1475 unsigned subkey_size; 1476 int err = 0, i, r; 1477 1478 /* Ignore extra keys (which are used for IV etc) */ 1479 subkey_size = (cc->key_size - cc->key_extra_size) >> ilog2(cc->tfms_count); 1480 1481 for (i = 0; i < cc->tfms_count; i++) { 1482 r = crypto_skcipher_setkey(cc->tfms[i], 1483 cc->key + (i * subkey_size), 1484 subkey_size); 1485 if (r) 1486 err = r; 1487 } 1488 1489 return err; 1490 } 1491 1492 static int crypt_set_key(struct crypt_config *cc, char *key) 1493 { 1494 int r = -EINVAL; 1495 int key_string_len = strlen(key); 1496 1497 /* The key size may not be changed. */ 1498 if (cc->key_size != (key_string_len >> 1)) 1499 goto out; 1500 1501 /* Hyphen (which gives a key_size of zero) means there is no key. */ 1502 if (!cc->key_size && strcmp(key, "-")) 1503 goto out; 1504 1505 if (cc->key_size && crypt_decode_key(cc->key, key, cc->key_size) < 0) 1506 goto out; 1507 1508 set_bit(DM_CRYPT_KEY_VALID, &cc->flags); 1509 1510 r = crypt_setkey_allcpus(cc); 1511 1512 out: 1513 /* Hex key string not needed after here, so wipe it. */ 1514 memset(key, '0', key_string_len); 1515 1516 return r; 1517 } 1518 1519 static int crypt_wipe_key(struct crypt_config *cc) 1520 { 1521 clear_bit(DM_CRYPT_KEY_VALID, &cc->flags); 1522 memset(&cc->key, 0, cc->key_size * sizeof(u8)); 1523 1524 return crypt_setkey_allcpus(cc); 1525 } 1526 1527 static void crypt_dtr(struct dm_target *ti) 1528 { 1529 struct crypt_config *cc = ti->private; 1530 1531 ti->private = NULL; 1532 1533 if (!cc) 1534 return; 1535 1536 if (cc->write_thread) { 1537 spin_lock_irq(&cc->write_thread_wait.lock); 1538 set_bit(DM_CRYPT_EXIT_THREAD, &cc->flags); 1539 wake_up_locked(&cc->write_thread_wait); 1540 spin_unlock_irq(&cc->write_thread_wait.lock); 1541 kthread_stop(cc->write_thread); 1542 } 1543 1544 if (cc->io_queue) 1545 destroy_workqueue(cc->io_queue); 1546 if (cc->crypt_queue) 1547 destroy_workqueue(cc->crypt_queue); 1548 1549 crypt_free_tfms(cc); 1550 1551 if (cc->bs) 1552 bioset_free(cc->bs); 1553 1554 mempool_destroy(cc->page_pool); 1555 mempool_destroy(cc->req_pool); 1556 1557 if (cc->iv_gen_ops && cc->iv_gen_ops->dtr) 1558 cc->iv_gen_ops->dtr(cc); 1559 1560 if (cc->dev) 1561 dm_put_device(ti, cc->dev); 1562 1563 kzfree(cc->cipher); 1564 kzfree(cc->cipher_string); 1565 1566 /* Must zero key material before freeing */ 1567 kzfree(cc); 1568 } 1569 1570 static int crypt_ctr_cipher(struct dm_target *ti, 1571 char *cipher_in, char *key) 1572 { 1573 struct crypt_config *cc = ti->private; 1574 char *tmp, *cipher, *chainmode, *ivmode, *ivopts, *keycount; 1575 char *cipher_api = NULL; 1576 int ret = -EINVAL; 1577 char dummy; 1578 1579 /* Convert to crypto api definition? */ 1580 if (strchr(cipher_in, '(')) { 1581 ti->error = "Bad cipher specification"; 1582 return -EINVAL; 1583 } 1584 1585 cc->cipher_string = kstrdup(cipher_in, GFP_KERNEL); 1586 if (!cc->cipher_string) 1587 goto bad_mem; 1588 1589 /* 1590 * Legacy dm-crypt cipher specification 1591 * cipher[:keycount]-mode-iv:ivopts 1592 */ 1593 tmp = cipher_in; 1594 keycount = strsep(&tmp, "-"); 1595 cipher = strsep(&keycount, ":"); 1596 1597 if (!keycount) 1598 cc->tfms_count = 1; 1599 else if (sscanf(keycount, "%u%c", &cc->tfms_count, &dummy) != 1 || 1600 !is_power_of_2(cc->tfms_count)) { 1601 ti->error = "Bad cipher key count specification"; 1602 return -EINVAL; 1603 } 1604 cc->key_parts = cc->tfms_count; 1605 cc->key_extra_size = 0; 1606 1607 cc->cipher = kstrdup(cipher, GFP_KERNEL); 1608 if (!cc->cipher) 1609 goto bad_mem; 1610 1611 chainmode = strsep(&tmp, "-"); 1612 ivopts = strsep(&tmp, "-"); 1613 ivmode = strsep(&ivopts, ":"); 1614 1615 if (tmp) 1616 DMWARN("Ignoring unexpected additional cipher options"); 1617 1618 /* 1619 * For compatibility with the original dm-crypt mapping format, if 1620 * only the cipher name is supplied, use cbc-plain. 1621 */ 1622 if (!chainmode || (!strcmp(chainmode, "plain") && !ivmode)) { 1623 chainmode = "cbc"; 1624 ivmode = "plain"; 1625 } 1626 1627 if (strcmp(chainmode, "ecb") && !ivmode) { 1628 ti->error = "IV mechanism required"; 1629 return -EINVAL; 1630 } 1631 1632 cipher_api = kmalloc(CRYPTO_MAX_ALG_NAME, GFP_KERNEL); 1633 if (!cipher_api) 1634 goto bad_mem; 1635 1636 ret = snprintf(cipher_api, CRYPTO_MAX_ALG_NAME, 1637 "%s(%s)", chainmode, cipher); 1638 if (ret < 0) { 1639 kfree(cipher_api); 1640 goto bad_mem; 1641 } 1642 1643 /* Allocate cipher */ 1644 ret = crypt_alloc_tfms(cc, cipher_api); 1645 if (ret < 0) { 1646 ti->error = "Error allocating crypto tfm"; 1647 goto bad; 1648 } 1649 1650 /* Initialize IV */ 1651 cc->iv_size = crypto_skcipher_ivsize(any_tfm(cc)); 1652 if (cc->iv_size) 1653 /* at least a 64 bit sector number should fit in our buffer */ 1654 cc->iv_size = max(cc->iv_size, 1655 (unsigned int)(sizeof(u64) / sizeof(u8))); 1656 else if (ivmode) { 1657 DMWARN("Selected cipher does not support IVs"); 1658 ivmode = NULL; 1659 } 1660 1661 /* Choose ivmode, see comments at iv code. */ 1662 if (ivmode == NULL) 1663 cc->iv_gen_ops = NULL; 1664 else if (strcmp(ivmode, "plain") == 0) 1665 cc->iv_gen_ops = &crypt_iv_plain_ops; 1666 else if (strcmp(ivmode, "plain64") == 0) 1667 cc->iv_gen_ops = &crypt_iv_plain64_ops; 1668 else if (strcmp(ivmode, "essiv") == 0) 1669 cc->iv_gen_ops = &crypt_iv_essiv_ops; 1670 else if (strcmp(ivmode, "benbi") == 0) 1671 cc->iv_gen_ops = &crypt_iv_benbi_ops; 1672 else if (strcmp(ivmode, "null") == 0) 1673 cc->iv_gen_ops = &crypt_iv_null_ops; 1674 else if (strcmp(ivmode, "lmk") == 0) { 1675 cc->iv_gen_ops = &crypt_iv_lmk_ops; 1676 /* 1677 * Version 2 and 3 is recognised according 1678 * to length of provided multi-key string. 1679 * If present (version 3), last key is used as IV seed. 1680 * All keys (including IV seed) are always the same size. 1681 */ 1682 if (cc->key_size % cc->key_parts) { 1683 cc->key_parts++; 1684 cc->key_extra_size = cc->key_size / cc->key_parts; 1685 } 1686 } else if (strcmp(ivmode, "tcw") == 0) { 1687 cc->iv_gen_ops = &crypt_iv_tcw_ops; 1688 cc->key_parts += 2; /* IV + whitening */ 1689 cc->key_extra_size = cc->iv_size + TCW_WHITENING_SIZE; 1690 } else { 1691 ret = -EINVAL; 1692 ti->error = "Invalid IV mode"; 1693 goto bad; 1694 } 1695 1696 /* Initialize and set key */ 1697 ret = crypt_set_key(cc, key); 1698 if (ret < 0) { 1699 ti->error = "Error decoding and setting key"; 1700 goto bad; 1701 } 1702 1703 /* Allocate IV */ 1704 if (cc->iv_gen_ops && cc->iv_gen_ops->ctr) { 1705 ret = cc->iv_gen_ops->ctr(cc, ti, ivopts); 1706 if (ret < 0) { 1707 ti->error = "Error creating IV"; 1708 goto bad; 1709 } 1710 } 1711 1712 /* Initialize IV (set keys for ESSIV etc) */ 1713 if (cc->iv_gen_ops && cc->iv_gen_ops->init) { 1714 ret = cc->iv_gen_ops->init(cc); 1715 if (ret < 0) { 1716 ti->error = "Error initialising IV"; 1717 goto bad; 1718 } 1719 } 1720 1721 ret = 0; 1722 bad: 1723 kfree(cipher_api); 1724 return ret; 1725 1726 bad_mem: 1727 ti->error = "Cannot allocate cipher strings"; 1728 return -ENOMEM; 1729 } 1730 1731 /* 1732 * Construct an encryption mapping: 1733 * <cipher> <key> <iv_offset> <dev_path> <start> 1734 */ 1735 static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv) 1736 { 1737 struct crypt_config *cc; 1738 unsigned int key_size, opt_params; 1739 unsigned long long tmpll; 1740 int ret; 1741 size_t iv_size_padding; 1742 struct dm_arg_set as; 1743 const char *opt_string; 1744 char dummy; 1745 1746 static struct dm_arg _args[] = { 1747 {0, 3, "Invalid number of feature args"}, 1748 }; 1749 1750 if (argc < 5) { 1751 ti->error = "Not enough arguments"; 1752 return -EINVAL; 1753 } 1754 1755 key_size = strlen(argv[1]) >> 1; 1756 1757 cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL); 1758 if (!cc) { 1759 ti->error = "Cannot allocate encryption context"; 1760 return -ENOMEM; 1761 } 1762 cc->key_size = key_size; 1763 1764 ti->private = cc; 1765 ret = crypt_ctr_cipher(ti, argv[0], argv[1]); 1766 if (ret < 0) 1767 goto bad; 1768 1769 cc->dmreq_start = sizeof(struct skcipher_request); 1770 cc->dmreq_start += crypto_skcipher_reqsize(any_tfm(cc)); 1771 cc->dmreq_start = ALIGN(cc->dmreq_start, __alignof__(struct dm_crypt_request)); 1772 1773 if (crypto_skcipher_alignmask(any_tfm(cc)) < CRYPTO_MINALIGN) { 1774 /* Allocate the padding exactly */ 1775 iv_size_padding = -(cc->dmreq_start + sizeof(struct dm_crypt_request)) 1776 & crypto_skcipher_alignmask(any_tfm(cc)); 1777 } else { 1778 /* 1779 * If the cipher requires greater alignment than kmalloc 1780 * alignment, we don't know the exact position of the 1781 * initialization vector. We must assume worst case. 1782 */ 1783 iv_size_padding = crypto_skcipher_alignmask(any_tfm(cc)); 1784 } 1785 1786 ret = -ENOMEM; 1787 cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start + 1788 sizeof(struct dm_crypt_request) + iv_size_padding + cc->iv_size); 1789 if (!cc->req_pool) { 1790 ti->error = "Cannot allocate crypt request mempool"; 1791 goto bad; 1792 } 1793 1794 cc->per_bio_data_size = ti->per_io_data_size = 1795 ALIGN(sizeof(struct dm_crypt_io) + cc->dmreq_start + 1796 sizeof(struct dm_crypt_request) + iv_size_padding + cc->iv_size, 1797 ARCH_KMALLOC_MINALIGN); 1798 1799 cc->page_pool = mempool_create_page_pool(BIO_MAX_PAGES, 0); 1800 if (!cc->page_pool) { 1801 ti->error = "Cannot allocate page mempool"; 1802 goto bad; 1803 } 1804 1805 cc->bs = bioset_create(MIN_IOS, 0); 1806 if (!cc->bs) { 1807 ti->error = "Cannot allocate crypt bioset"; 1808 goto bad; 1809 } 1810 1811 mutex_init(&cc->bio_alloc_lock); 1812 1813 ret = -EINVAL; 1814 if (sscanf(argv[2], "%llu%c", &tmpll, &dummy) != 1) { 1815 ti->error = "Invalid iv_offset sector"; 1816 goto bad; 1817 } 1818 cc->iv_offset = tmpll; 1819 1820 ret = dm_get_device(ti, argv[3], dm_table_get_mode(ti->table), &cc->dev); 1821 if (ret) { 1822 ti->error = "Device lookup failed"; 1823 goto bad; 1824 } 1825 1826 ret = -EINVAL; 1827 if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1) { 1828 ti->error = "Invalid device sector"; 1829 goto bad; 1830 } 1831 cc->start = tmpll; 1832 1833 argv += 5; 1834 argc -= 5; 1835 1836 /* Optional parameters */ 1837 if (argc) { 1838 as.argc = argc; 1839 as.argv = argv; 1840 1841 ret = dm_read_arg_group(_args, &as, &opt_params, &ti->error); 1842 if (ret) 1843 goto bad; 1844 1845 ret = -EINVAL; 1846 while (opt_params--) { 1847 opt_string = dm_shift_arg(&as); 1848 if (!opt_string) { 1849 ti->error = "Not enough feature arguments"; 1850 goto bad; 1851 } 1852 1853 if (!strcasecmp(opt_string, "allow_discards")) 1854 ti->num_discard_bios = 1; 1855 1856 else if (!strcasecmp(opt_string, "same_cpu_crypt")) 1857 set_bit(DM_CRYPT_SAME_CPU, &cc->flags); 1858 1859 else if (!strcasecmp(opt_string, "submit_from_crypt_cpus")) 1860 set_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags); 1861 1862 else { 1863 ti->error = "Invalid feature arguments"; 1864 goto bad; 1865 } 1866 } 1867 } 1868 1869 ret = -ENOMEM; 1870 cc->io_queue = alloc_workqueue("kcryptd_io", WQ_MEM_RECLAIM, 1); 1871 if (!cc->io_queue) { 1872 ti->error = "Couldn't create kcryptd io queue"; 1873 goto bad; 1874 } 1875 1876 if (test_bit(DM_CRYPT_SAME_CPU, &cc->flags)) 1877 cc->crypt_queue = alloc_workqueue("kcryptd", WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM, 1); 1878 else 1879 cc->crypt_queue = alloc_workqueue("kcryptd", WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM | WQ_UNBOUND, 1880 num_online_cpus()); 1881 if (!cc->crypt_queue) { 1882 ti->error = "Couldn't create kcryptd queue"; 1883 goto bad; 1884 } 1885 1886 init_waitqueue_head(&cc->write_thread_wait); 1887 cc->write_tree = RB_ROOT; 1888 1889 cc->write_thread = kthread_create(dmcrypt_write, cc, "dmcrypt_write"); 1890 if (IS_ERR(cc->write_thread)) { 1891 ret = PTR_ERR(cc->write_thread); 1892 cc->write_thread = NULL; 1893 ti->error = "Couldn't spawn write thread"; 1894 goto bad; 1895 } 1896 wake_up_process(cc->write_thread); 1897 1898 ti->num_flush_bios = 1; 1899 ti->discard_zeroes_data_unsupported = true; 1900 1901 return 0; 1902 1903 bad: 1904 crypt_dtr(ti); 1905 return ret; 1906 } 1907 1908 static int crypt_map(struct dm_target *ti, struct bio *bio) 1909 { 1910 struct dm_crypt_io *io; 1911 struct crypt_config *cc = ti->private; 1912 1913 /* 1914 * If bio is REQ_FLUSH or REQ_DISCARD, just bypass crypt queues. 1915 * - for REQ_FLUSH device-mapper core ensures that no IO is in-flight 1916 * - for REQ_DISCARD caller must use flush if IO ordering matters 1917 */ 1918 if (unlikely(bio->bi_rw & (REQ_FLUSH | REQ_DISCARD))) { 1919 bio->bi_bdev = cc->dev->bdev; 1920 if (bio_sectors(bio)) 1921 bio->bi_iter.bi_sector = cc->start + 1922 dm_target_offset(ti, bio->bi_iter.bi_sector); 1923 return DM_MAPIO_REMAPPED; 1924 } 1925 1926 io = dm_per_bio_data(bio, cc->per_bio_data_size); 1927 crypt_io_init(io, cc, bio, dm_target_offset(ti, bio->bi_iter.bi_sector)); 1928 io->ctx.req = (struct skcipher_request *)(io + 1); 1929 1930 if (bio_data_dir(io->base_bio) == READ) { 1931 if (kcryptd_io_read(io, GFP_NOWAIT)) 1932 kcryptd_queue_read(io); 1933 } else 1934 kcryptd_queue_crypt(io); 1935 1936 return DM_MAPIO_SUBMITTED; 1937 } 1938 1939 static void crypt_status(struct dm_target *ti, status_type_t type, 1940 unsigned status_flags, char *result, unsigned maxlen) 1941 { 1942 struct crypt_config *cc = ti->private; 1943 unsigned i, sz = 0; 1944 int num_feature_args = 0; 1945 1946 switch (type) { 1947 case STATUSTYPE_INFO: 1948 result[0] = '\0'; 1949 break; 1950 1951 case STATUSTYPE_TABLE: 1952 DMEMIT("%s ", cc->cipher_string); 1953 1954 if (cc->key_size > 0) 1955 for (i = 0; i < cc->key_size; i++) 1956 DMEMIT("%02x", cc->key[i]); 1957 else 1958 DMEMIT("-"); 1959 1960 DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset, 1961 cc->dev->name, (unsigned long long)cc->start); 1962 1963 num_feature_args += !!ti->num_discard_bios; 1964 num_feature_args += test_bit(DM_CRYPT_SAME_CPU, &cc->flags); 1965 num_feature_args += test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags); 1966 if (num_feature_args) { 1967 DMEMIT(" %d", num_feature_args); 1968 if (ti->num_discard_bios) 1969 DMEMIT(" allow_discards"); 1970 if (test_bit(DM_CRYPT_SAME_CPU, &cc->flags)) 1971 DMEMIT(" same_cpu_crypt"); 1972 if (test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags)) 1973 DMEMIT(" submit_from_crypt_cpus"); 1974 } 1975 1976 break; 1977 } 1978 } 1979 1980 static void crypt_postsuspend(struct dm_target *ti) 1981 { 1982 struct crypt_config *cc = ti->private; 1983 1984 set_bit(DM_CRYPT_SUSPENDED, &cc->flags); 1985 } 1986 1987 static int crypt_preresume(struct dm_target *ti) 1988 { 1989 struct crypt_config *cc = ti->private; 1990 1991 if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) { 1992 DMERR("aborting resume - crypt key is not set."); 1993 return -EAGAIN; 1994 } 1995 1996 return 0; 1997 } 1998 1999 static void crypt_resume(struct dm_target *ti) 2000 { 2001 struct crypt_config *cc = ti->private; 2002 2003 clear_bit(DM_CRYPT_SUSPENDED, &cc->flags); 2004 } 2005 2006 /* Message interface 2007 * key set <key> 2008 * key wipe 2009 */ 2010 static int crypt_message(struct dm_target *ti, unsigned argc, char **argv) 2011 { 2012 struct crypt_config *cc = ti->private; 2013 int ret = -EINVAL; 2014 2015 if (argc < 2) 2016 goto error; 2017 2018 if (!strcasecmp(argv[0], "key")) { 2019 if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) { 2020 DMWARN("not suspended during key manipulation."); 2021 return -EINVAL; 2022 } 2023 if (argc == 3 && !strcasecmp(argv[1], "set")) { 2024 ret = crypt_set_key(cc, argv[2]); 2025 if (ret) 2026 return ret; 2027 if (cc->iv_gen_ops && cc->iv_gen_ops->init) 2028 ret = cc->iv_gen_ops->init(cc); 2029 return ret; 2030 } 2031 if (argc == 2 && !strcasecmp(argv[1], "wipe")) { 2032 if (cc->iv_gen_ops && cc->iv_gen_ops->wipe) { 2033 ret = cc->iv_gen_ops->wipe(cc); 2034 if (ret) 2035 return ret; 2036 } 2037 return crypt_wipe_key(cc); 2038 } 2039 } 2040 2041 error: 2042 DMWARN("unrecognised message received."); 2043 return -EINVAL; 2044 } 2045 2046 static int crypt_iterate_devices(struct dm_target *ti, 2047 iterate_devices_callout_fn fn, void *data) 2048 { 2049 struct crypt_config *cc = ti->private; 2050 2051 return fn(ti, cc->dev, cc->start, ti->len, data); 2052 } 2053 2054 static void crypt_io_hints(struct dm_target *ti, struct queue_limits *limits) 2055 { 2056 /* 2057 * Unfortunate constraint that is required to avoid the potential 2058 * for exceeding underlying device's max_segments limits -- due to 2059 * crypt_alloc_buffer() possibly allocating pages for the encryption 2060 * bio that are not as physically contiguous as the original bio. 2061 */ 2062 limits->max_segment_size = PAGE_SIZE; 2063 } 2064 2065 static struct target_type crypt_target = { 2066 .name = "crypt", 2067 .version = {1, 14, 1}, 2068 .module = THIS_MODULE, 2069 .ctr = crypt_ctr, 2070 .dtr = crypt_dtr, 2071 .map = crypt_map, 2072 .status = crypt_status, 2073 .postsuspend = crypt_postsuspend, 2074 .preresume = crypt_preresume, 2075 .resume = crypt_resume, 2076 .message = crypt_message, 2077 .iterate_devices = crypt_iterate_devices, 2078 .io_hints = crypt_io_hints, 2079 }; 2080 2081 static int __init dm_crypt_init(void) 2082 { 2083 int r; 2084 2085 r = dm_register_target(&crypt_target); 2086 if (r < 0) 2087 DMERR("register failed %d", r); 2088 2089 return r; 2090 } 2091 2092 static void __exit dm_crypt_exit(void) 2093 { 2094 dm_unregister_target(&crypt_target); 2095 } 2096 2097 module_init(dm_crypt_init); 2098 module_exit(dm_crypt_exit); 2099 2100 MODULE_AUTHOR("Jana Saout <jana@saout.de>"); 2101 MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption"); 2102 MODULE_LICENSE("GPL"); 2103