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