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 * 6 * This file is released under the GPL. 7 */ 8 9 #include <linux/completion.h> 10 #include <linux/err.h> 11 #include <linux/module.h> 12 #include <linux/init.h> 13 #include <linux/kernel.h> 14 #include <linux/bio.h> 15 #include <linux/blkdev.h> 16 #include <linux/mempool.h> 17 #include <linux/slab.h> 18 #include <linux/crypto.h> 19 #include <linux/workqueue.h> 20 #include <linux/backing-dev.h> 21 #include <linux/percpu.h> 22 #include <linux/atomic.h> 23 #include <linux/scatterlist.h> 24 #include <asm/page.h> 25 #include <asm/unaligned.h> 26 #include <crypto/hash.h> 27 #include <crypto/md5.h> 28 #include <crypto/algapi.h> 29 30 #include <linux/device-mapper.h> 31 32 #define DM_MSG_PREFIX "crypt" 33 34 /* 35 * context holding the current state of a multi-part conversion 36 */ 37 struct convert_context { 38 struct completion restart; 39 struct bio *bio_in; 40 struct bio *bio_out; 41 unsigned int offset_in; 42 unsigned int offset_out; 43 unsigned int idx_in; 44 unsigned int idx_out; 45 sector_t cc_sector; 46 atomic_t cc_pending; 47 }; 48 49 /* 50 * per bio private data 51 */ 52 struct dm_crypt_io { 53 struct crypt_config *cc; 54 struct bio *base_bio; 55 struct work_struct work; 56 57 struct convert_context ctx; 58 59 atomic_t io_pending; 60 int error; 61 sector_t sector; 62 struct dm_crypt_io *base_io; 63 }; 64 65 struct dm_crypt_request { 66 struct convert_context *ctx; 67 struct scatterlist sg_in; 68 struct scatterlist sg_out; 69 sector_t iv_sector; 70 }; 71 72 struct crypt_config; 73 74 struct crypt_iv_operations { 75 int (*ctr)(struct crypt_config *cc, struct dm_target *ti, 76 const char *opts); 77 void (*dtr)(struct crypt_config *cc); 78 int (*init)(struct crypt_config *cc); 79 int (*wipe)(struct crypt_config *cc); 80 int (*generator)(struct crypt_config *cc, u8 *iv, 81 struct dm_crypt_request *dmreq); 82 int (*post)(struct crypt_config *cc, u8 *iv, 83 struct dm_crypt_request *dmreq); 84 }; 85 86 struct iv_essiv_private { 87 struct crypto_hash *hash_tfm; 88 u8 *salt; 89 }; 90 91 struct iv_benbi_private { 92 int shift; 93 }; 94 95 #define LMK_SEED_SIZE 64 /* hash + 0 */ 96 struct iv_lmk_private { 97 struct crypto_shash *hash_tfm; 98 u8 *seed; 99 }; 100 101 /* 102 * Crypt: maps a linear range of a block device 103 * and encrypts / decrypts at the same time. 104 */ 105 enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID }; 106 107 /* 108 * Duplicated per-CPU state for cipher. 109 */ 110 struct crypt_cpu { 111 struct ablkcipher_request *req; 112 }; 113 114 /* 115 * The fields in here must be read only after initialization, 116 * changing state should be in crypt_cpu. 117 */ 118 struct crypt_config { 119 struct dm_dev *dev; 120 sector_t start; 121 122 /* 123 * pool for per bio private data, crypto requests and 124 * encryption requeusts/buffer pages 125 */ 126 mempool_t *io_pool; 127 mempool_t *req_pool; 128 mempool_t *page_pool; 129 struct bio_set *bs; 130 131 struct workqueue_struct *io_queue; 132 struct workqueue_struct *crypt_queue; 133 134 char *cipher; 135 char *cipher_string; 136 137 struct crypt_iv_operations *iv_gen_ops; 138 union { 139 struct iv_essiv_private essiv; 140 struct iv_benbi_private benbi; 141 struct iv_lmk_private lmk; 142 } iv_gen_private; 143 sector_t iv_offset; 144 unsigned int iv_size; 145 146 /* 147 * Duplicated per cpu state. Access through 148 * per_cpu_ptr() only. 149 */ 150 struct crypt_cpu __percpu *cpu; 151 152 /* ESSIV: struct crypto_cipher *essiv_tfm */ 153 void *iv_private; 154 struct crypto_ablkcipher **tfms; 155 unsigned tfms_count; 156 157 /* 158 * Layout of each crypto request: 159 * 160 * struct ablkcipher_request 161 * context 162 * padding 163 * struct dm_crypt_request 164 * padding 165 * IV 166 * 167 * The padding is added so that dm_crypt_request and the IV are 168 * correctly aligned. 169 */ 170 unsigned int dmreq_start; 171 172 unsigned long flags; 173 unsigned int key_size; 174 unsigned int key_parts; 175 u8 key[0]; 176 }; 177 178 #define MIN_IOS 16 179 #define MIN_POOL_PAGES 32 180 181 static struct kmem_cache *_crypt_io_pool; 182 183 static void clone_init(struct dm_crypt_io *, struct bio *); 184 static void kcryptd_queue_crypt(struct dm_crypt_io *io); 185 static u8 *iv_of_dmreq(struct crypt_config *cc, struct dm_crypt_request *dmreq); 186 187 static struct crypt_cpu *this_crypt_config(struct crypt_config *cc) 188 { 189 return this_cpu_ptr(cc->cpu); 190 } 191 192 /* 193 * Use this to access cipher attributes that are the same for each CPU. 194 */ 195 static struct crypto_ablkcipher *any_tfm(struct crypt_config *cc) 196 { 197 return cc->tfms[0]; 198 } 199 200 /* 201 * Different IV generation algorithms: 202 * 203 * plain: the initial vector is the 32-bit little-endian version of the sector 204 * number, padded with zeros if necessary. 205 * 206 * plain64: the initial vector is the 64-bit little-endian version of the sector 207 * number, padded with zeros if necessary. 208 * 209 * essiv: "encrypted sector|salt initial vector", the sector number is 210 * encrypted with the bulk cipher using a salt as key. The salt 211 * should be derived from the bulk cipher's key via hashing. 212 * 213 * benbi: the 64-bit "big-endian 'narrow block'-count", starting at 1 214 * (needed for LRW-32-AES and possible other narrow block modes) 215 * 216 * null: the initial vector is always zero. Provides compatibility with 217 * obsolete loop_fish2 devices. Do not use for new devices. 218 * 219 * lmk: Compatible implementation of the block chaining mode used 220 * by the Loop-AES block device encryption system 221 * designed by Jari Ruusu. See http://loop-aes.sourceforge.net/ 222 * It operates on full 512 byte sectors and uses CBC 223 * with an IV derived from the sector number, the data and 224 * optionally extra IV seed. 225 * This means that after decryption the first block 226 * of sector must be tweaked according to decrypted data. 227 * Loop-AES can use three encryption schemes: 228 * version 1: is plain aes-cbc mode 229 * version 2: uses 64 multikey scheme with lmk IV generator 230 * version 3: the same as version 2 with additional IV seed 231 * (it uses 65 keys, last key is used as IV seed) 232 * 233 * plumb: unimplemented, see: 234 * http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454 235 */ 236 237 static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv, 238 struct dm_crypt_request *dmreq) 239 { 240 memset(iv, 0, cc->iv_size); 241 *(__le32 *)iv = cpu_to_le32(dmreq->iv_sector & 0xffffffff); 242 243 return 0; 244 } 245 246 static int crypt_iv_plain64_gen(struct crypt_config *cc, u8 *iv, 247 struct dm_crypt_request *dmreq) 248 { 249 memset(iv, 0, cc->iv_size); 250 *(__le64 *)iv = cpu_to_le64(dmreq->iv_sector); 251 252 return 0; 253 } 254 255 /* Initialise ESSIV - compute salt but no local memory allocations */ 256 static int crypt_iv_essiv_init(struct crypt_config *cc) 257 { 258 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv; 259 struct hash_desc desc; 260 struct scatterlist sg; 261 struct crypto_cipher *essiv_tfm; 262 int err; 263 264 sg_init_one(&sg, cc->key, cc->key_size); 265 desc.tfm = essiv->hash_tfm; 266 desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; 267 268 err = crypto_hash_digest(&desc, &sg, cc->key_size, essiv->salt); 269 if (err) 270 return err; 271 272 essiv_tfm = cc->iv_private; 273 274 err = crypto_cipher_setkey(essiv_tfm, essiv->salt, 275 crypto_hash_digestsize(essiv->hash_tfm)); 276 if (err) 277 return err; 278 279 return 0; 280 } 281 282 /* Wipe salt and reset key derived from volume key */ 283 static int crypt_iv_essiv_wipe(struct crypt_config *cc) 284 { 285 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv; 286 unsigned salt_size = crypto_hash_digestsize(essiv->hash_tfm); 287 struct crypto_cipher *essiv_tfm; 288 int r, err = 0; 289 290 memset(essiv->salt, 0, salt_size); 291 292 essiv_tfm = cc->iv_private; 293 r = crypto_cipher_setkey(essiv_tfm, essiv->salt, salt_size); 294 if (r) 295 err = r; 296 297 return err; 298 } 299 300 /* Set up per cpu cipher state */ 301 static struct crypto_cipher *setup_essiv_cpu(struct crypt_config *cc, 302 struct dm_target *ti, 303 u8 *salt, unsigned saltsize) 304 { 305 struct crypto_cipher *essiv_tfm; 306 int err; 307 308 /* Setup the essiv_tfm with the given salt */ 309 essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC); 310 if (IS_ERR(essiv_tfm)) { 311 ti->error = "Error allocating crypto tfm for ESSIV"; 312 return essiv_tfm; 313 } 314 315 if (crypto_cipher_blocksize(essiv_tfm) != 316 crypto_ablkcipher_ivsize(any_tfm(cc))) { 317 ti->error = "Block size of ESSIV cipher does " 318 "not match IV size of block cipher"; 319 crypto_free_cipher(essiv_tfm); 320 return ERR_PTR(-EINVAL); 321 } 322 323 err = crypto_cipher_setkey(essiv_tfm, salt, saltsize); 324 if (err) { 325 ti->error = "Failed to set key for ESSIV cipher"; 326 crypto_free_cipher(essiv_tfm); 327 return ERR_PTR(err); 328 } 329 330 return essiv_tfm; 331 } 332 333 static void crypt_iv_essiv_dtr(struct crypt_config *cc) 334 { 335 struct crypto_cipher *essiv_tfm; 336 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv; 337 338 crypto_free_hash(essiv->hash_tfm); 339 essiv->hash_tfm = NULL; 340 341 kzfree(essiv->salt); 342 essiv->salt = NULL; 343 344 essiv_tfm = cc->iv_private; 345 346 if (essiv_tfm) 347 crypto_free_cipher(essiv_tfm); 348 349 cc->iv_private = NULL; 350 } 351 352 static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti, 353 const char *opts) 354 { 355 struct crypto_cipher *essiv_tfm = NULL; 356 struct crypto_hash *hash_tfm = NULL; 357 u8 *salt = NULL; 358 int err; 359 360 if (!opts) { 361 ti->error = "Digest algorithm missing for ESSIV mode"; 362 return -EINVAL; 363 } 364 365 /* Allocate hash algorithm */ 366 hash_tfm = crypto_alloc_hash(opts, 0, CRYPTO_ALG_ASYNC); 367 if (IS_ERR(hash_tfm)) { 368 ti->error = "Error initializing ESSIV hash"; 369 err = PTR_ERR(hash_tfm); 370 goto bad; 371 } 372 373 salt = kzalloc(crypto_hash_digestsize(hash_tfm), GFP_KERNEL); 374 if (!salt) { 375 ti->error = "Error kmallocing salt storage in ESSIV"; 376 err = -ENOMEM; 377 goto bad; 378 } 379 380 cc->iv_gen_private.essiv.salt = salt; 381 cc->iv_gen_private.essiv.hash_tfm = hash_tfm; 382 383 essiv_tfm = setup_essiv_cpu(cc, ti, salt, 384 crypto_hash_digestsize(hash_tfm)); 385 if (IS_ERR(essiv_tfm)) { 386 crypt_iv_essiv_dtr(cc); 387 return PTR_ERR(essiv_tfm); 388 } 389 cc->iv_private = essiv_tfm; 390 391 return 0; 392 393 bad: 394 if (hash_tfm && !IS_ERR(hash_tfm)) 395 crypto_free_hash(hash_tfm); 396 kfree(salt); 397 return err; 398 } 399 400 static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv, 401 struct dm_crypt_request *dmreq) 402 { 403 struct crypto_cipher *essiv_tfm = cc->iv_private; 404 405 memset(iv, 0, cc->iv_size); 406 *(__le64 *)iv = cpu_to_le64(dmreq->iv_sector); 407 crypto_cipher_encrypt_one(essiv_tfm, iv, iv); 408 409 return 0; 410 } 411 412 static int crypt_iv_benbi_ctr(struct crypt_config *cc, struct dm_target *ti, 413 const char *opts) 414 { 415 unsigned bs = crypto_ablkcipher_blocksize(any_tfm(cc)); 416 int log = ilog2(bs); 417 418 /* we need to calculate how far we must shift the sector count 419 * to get the cipher block count, we use this shift in _gen */ 420 421 if (1 << log != bs) { 422 ti->error = "cypher blocksize is not a power of 2"; 423 return -EINVAL; 424 } 425 426 if (log > 9) { 427 ti->error = "cypher blocksize is > 512"; 428 return -EINVAL; 429 } 430 431 cc->iv_gen_private.benbi.shift = 9 - log; 432 433 return 0; 434 } 435 436 static void crypt_iv_benbi_dtr(struct crypt_config *cc) 437 { 438 } 439 440 static int crypt_iv_benbi_gen(struct crypt_config *cc, u8 *iv, 441 struct dm_crypt_request *dmreq) 442 { 443 __be64 val; 444 445 memset(iv, 0, cc->iv_size - sizeof(u64)); /* rest is cleared below */ 446 447 val = cpu_to_be64(((u64)dmreq->iv_sector << cc->iv_gen_private.benbi.shift) + 1); 448 put_unaligned(val, (__be64 *)(iv + cc->iv_size - sizeof(u64))); 449 450 return 0; 451 } 452 453 static int crypt_iv_null_gen(struct crypt_config *cc, u8 *iv, 454 struct dm_crypt_request *dmreq) 455 { 456 memset(iv, 0, cc->iv_size); 457 458 return 0; 459 } 460 461 static void crypt_iv_lmk_dtr(struct crypt_config *cc) 462 { 463 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk; 464 465 if (lmk->hash_tfm && !IS_ERR(lmk->hash_tfm)) 466 crypto_free_shash(lmk->hash_tfm); 467 lmk->hash_tfm = NULL; 468 469 kzfree(lmk->seed); 470 lmk->seed = NULL; 471 } 472 473 static int crypt_iv_lmk_ctr(struct crypt_config *cc, struct dm_target *ti, 474 const char *opts) 475 { 476 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk; 477 478 lmk->hash_tfm = crypto_alloc_shash("md5", 0, 0); 479 if (IS_ERR(lmk->hash_tfm)) { 480 ti->error = "Error initializing LMK hash"; 481 return PTR_ERR(lmk->hash_tfm); 482 } 483 484 /* No seed in LMK version 2 */ 485 if (cc->key_parts == cc->tfms_count) { 486 lmk->seed = NULL; 487 return 0; 488 } 489 490 lmk->seed = kzalloc(LMK_SEED_SIZE, GFP_KERNEL); 491 if (!lmk->seed) { 492 crypt_iv_lmk_dtr(cc); 493 ti->error = "Error kmallocing seed storage in LMK"; 494 return -ENOMEM; 495 } 496 497 return 0; 498 } 499 500 static int crypt_iv_lmk_init(struct crypt_config *cc) 501 { 502 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk; 503 int subkey_size = cc->key_size / cc->key_parts; 504 505 /* LMK seed is on the position of LMK_KEYS + 1 key */ 506 if (lmk->seed) 507 memcpy(lmk->seed, cc->key + (cc->tfms_count * subkey_size), 508 crypto_shash_digestsize(lmk->hash_tfm)); 509 510 return 0; 511 } 512 513 static int crypt_iv_lmk_wipe(struct crypt_config *cc) 514 { 515 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk; 516 517 if (lmk->seed) 518 memset(lmk->seed, 0, LMK_SEED_SIZE); 519 520 return 0; 521 } 522 523 static int crypt_iv_lmk_one(struct crypt_config *cc, u8 *iv, 524 struct dm_crypt_request *dmreq, 525 u8 *data) 526 { 527 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk; 528 struct { 529 struct shash_desc desc; 530 char ctx[crypto_shash_descsize(lmk->hash_tfm)]; 531 } sdesc; 532 struct md5_state md5state; 533 u32 buf[4]; 534 int i, r; 535 536 sdesc.desc.tfm = lmk->hash_tfm; 537 sdesc.desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; 538 539 r = crypto_shash_init(&sdesc.desc); 540 if (r) 541 return r; 542 543 if (lmk->seed) { 544 r = crypto_shash_update(&sdesc.desc, lmk->seed, LMK_SEED_SIZE); 545 if (r) 546 return r; 547 } 548 549 /* Sector is always 512B, block size 16, add data of blocks 1-31 */ 550 r = crypto_shash_update(&sdesc.desc, data + 16, 16 * 31); 551 if (r) 552 return r; 553 554 /* Sector is cropped to 56 bits here */ 555 buf[0] = cpu_to_le32(dmreq->iv_sector & 0xFFFFFFFF); 556 buf[1] = cpu_to_le32((((u64)dmreq->iv_sector >> 32) & 0x00FFFFFF) | 0x80000000); 557 buf[2] = cpu_to_le32(4024); 558 buf[3] = 0; 559 r = crypto_shash_update(&sdesc.desc, (u8 *)buf, sizeof(buf)); 560 if (r) 561 return r; 562 563 /* No MD5 padding here */ 564 r = crypto_shash_export(&sdesc.desc, &md5state); 565 if (r) 566 return r; 567 568 for (i = 0; i < MD5_HASH_WORDS; i++) 569 __cpu_to_le32s(&md5state.hash[i]); 570 memcpy(iv, &md5state.hash, cc->iv_size); 571 572 return 0; 573 } 574 575 static int crypt_iv_lmk_gen(struct crypt_config *cc, u8 *iv, 576 struct dm_crypt_request *dmreq) 577 { 578 u8 *src; 579 int r = 0; 580 581 if (bio_data_dir(dmreq->ctx->bio_in) == WRITE) { 582 src = kmap_atomic(sg_page(&dmreq->sg_in)); 583 r = crypt_iv_lmk_one(cc, iv, dmreq, src + dmreq->sg_in.offset); 584 kunmap_atomic(src); 585 } else 586 memset(iv, 0, cc->iv_size); 587 588 return r; 589 } 590 591 static int crypt_iv_lmk_post(struct crypt_config *cc, u8 *iv, 592 struct dm_crypt_request *dmreq) 593 { 594 u8 *dst; 595 int r; 596 597 if (bio_data_dir(dmreq->ctx->bio_in) == WRITE) 598 return 0; 599 600 dst = kmap_atomic(sg_page(&dmreq->sg_out)); 601 r = crypt_iv_lmk_one(cc, iv, dmreq, dst + dmreq->sg_out.offset); 602 603 /* Tweak the first block of plaintext sector */ 604 if (!r) 605 crypto_xor(dst + dmreq->sg_out.offset, iv, cc->iv_size); 606 607 kunmap_atomic(dst); 608 return r; 609 } 610 611 static struct crypt_iv_operations crypt_iv_plain_ops = { 612 .generator = crypt_iv_plain_gen 613 }; 614 615 static struct crypt_iv_operations crypt_iv_plain64_ops = { 616 .generator = crypt_iv_plain64_gen 617 }; 618 619 static struct crypt_iv_operations crypt_iv_essiv_ops = { 620 .ctr = crypt_iv_essiv_ctr, 621 .dtr = crypt_iv_essiv_dtr, 622 .init = crypt_iv_essiv_init, 623 .wipe = crypt_iv_essiv_wipe, 624 .generator = crypt_iv_essiv_gen 625 }; 626 627 static struct crypt_iv_operations crypt_iv_benbi_ops = { 628 .ctr = crypt_iv_benbi_ctr, 629 .dtr = crypt_iv_benbi_dtr, 630 .generator = crypt_iv_benbi_gen 631 }; 632 633 static struct crypt_iv_operations crypt_iv_null_ops = { 634 .generator = crypt_iv_null_gen 635 }; 636 637 static struct crypt_iv_operations crypt_iv_lmk_ops = { 638 .ctr = crypt_iv_lmk_ctr, 639 .dtr = crypt_iv_lmk_dtr, 640 .init = crypt_iv_lmk_init, 641 .wipe = crypt_iv_lmk_wipe, 642 .generator = crypt_iv_lmk_gen, 643 .post = crypt_iv_lmk_post 644 }; 645 646 static void crypt_convert_init(struct crypt_config *cc, 647 struct convert_context *ctx, 648 struct bio *bio_out, struct bio *bio_in, 649 sector_t sector) 650 { 651 ctx->bio_in = bio_in; 652 ctx->bio_out = bio_out; 653 ctx->offset_in = 0; 654 ctx->offset_out = 0; 655 ctx->idx_in = bio_in ? bio_in->bi_idx : 0; 656 ctx->idx_out = bio_out ? bio_out->bi_idx : 0; 657 ctx->cc_sector = sector + cc->iv_offset; 658 init_completion(&ctx->restart); 659 } 660 661 static struct dm_crypt_request *dmreq_of_req(struct crypt_config *cc, 662 struct ablkcipher_request *req) 663 { 664 return (struct dm_crypt_request *)((char *)req + cc->dmreq_start); 665 } 666 667 static struct ablkcipher_request *req_of_dmreq(struct crypt_config *cc, 668 struct dm_crypt_request *dmreq) 669 { 670 return (struct ablkcipher_request *)((char *)dmreq - cc->dmreq_start); 671 } 672 673 static u8 *iv_of_dmreq(struct crypt_config *cc, 674 struct dm_crypt_request *dmreq) 675 { 676 return (u8 *)ALIGN((unsigned long)(dmreq + 1), 677 crypto_ablkcipher_alignmask(any_tfm(cc)) + 1); 678 } 679 680 static int crypt_convert_block(struct crypt_config *cc, 681 struct convert_context *ctx, 682 struct ablkcipher_request *req) 683 { 684 struct bio_vec *bv_in = bio_iovec_idx(ctx->bio_in, ctx->idx_in); 685 struct bio_vec *bv_out = bio_iovec_idx(ctx->bio_out, ctx->idx_out); 686 struct dm_crypt_request *dmreq; 687 u8 *iv; 688 int r; 689 690 dmreq = dmreq_of_req(cc, req); 691 iv = iv_of_dmreq(cc, dmreq); 692 693 dmreq->iv_sector = ctx->cc_sector; 694 dmreq->ctx = ctx; 695 sg_init_table(&dmreq->sg_in, 1); 696 sg_set_page(&dmreq->sg_in, bv_in->bv_page, 1 << SECTOR_SHIFT, 697 bv_in->bv_offset + ctx->offset_in); 698 699 sg_init_table(&dmreq->sg_out, 1); 700 sg_set_page(&dmreq->sg_out, bv_out->bv_page, 1 << SECTOR_SHIFT, 701 bv_out->bv_offset + ctx->offset_out); 702 703 ctx->offset_in += 1 << SECTOR_SHIFT; 704 if (ctx->offset_in >= bv_in->bv_len) { 705 ctx->offset_in = 0; 706 ctx->idx_in++; 707 } 708 709 ctx->offset_out += 1 << SECTOR_SHIFT; 710 if (ctx->offset_out >= bv_out->bv_len) { 711 ctx->offset_out = 0; 712 ctx->idx_out++; 713 } 714 715 if (cc->iv_gen_ops) { 716 r = cc->iv_gen_ops->generator(cc, iv, dmreq); 717 if (r < 0) 718 return r; 719 } 720 721 ablkcipher_request_set_crypt(req, &dmreq->sg_in, &dmreq->sg_out, 722 1 << SECTOR_SHIFT, iv); 723 724 if (bio_data_dir(ctx->bio_in) == WRITE) 725 r = crypto_ablkcipher_encrypt(req); 726 else 727 r = crypto_ablkcipher_decrypt(req); 728 729 if (!r && cc->iv_gen_ops && cc->iv_gen_ops->post) 730 r = cc->iv_gen_ops->post(cc, iv, dmreq); 731 732 return r; 733 } 734 735 static void kcryptd_async_done(struct crypto_async_request *async_req, 736 int error); 737 738 static void crypt_alloc_req(struct crypt_config *cc, 739 struct convert_context *ctx) 740 { 741 struct crypt_cpu *this_cc = this_crypt_config(cc); 742 unsigned key_index = ctx->cc_sector & (cc->tfms_count - 1); 743 744 if (!this_cc->req) 745 this_cc->req = mempool_alloc(cc->req_pool, GFP_NOIO); 746 747 ablkcipher_request_set_tfm(this_cc->req, cc->tfms[key_index]); 748 ablkcipher_request_set_callback(this_cc->req, 749 CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, 750 kcryptd_async_done, dmreq_of_req(cc, this_cc->req)); 751 } 752 753 /* 754 * Encrypt / decrypt data from one bio to another one (can be the same one) 755 */ 756 static int crypt_convert(struct crypt_config *cc, 757 struct convert_context *ctx) 758 { 759 struct crypt_cpu *this_cc = this_crypt_config(cc); 760 int r; 761 762 atomic_set(&ctx->cc_pending, 1); 763 764 while(ctx->idx_in < ctx->bio_in->bi_vcnt && 765 ctx->idx_out < ctx->bio_out->bi_vcnt) { 766 767 crypt_alloc_req(cc, ctx); 768 769 atomic_inc(&ctx->cc_pending); 770 771 r = crypt_convert_block(cc, ctx, this_cc->req); 772 773 switch (r) { 774 /* async */ 775 case -EBUSY: 776 wait_for_completion(&ctx->restart); 777 INIT_COMPLETION(ctx->restart); 778 /* fall through*/ 779 case -EINPROGRESS: 780 this_cc->req = NULL; 781 ctx->cc_sector++; 782 continue; 783 784 /* sync */ 785 case 0: 786 atomic_dec(&ctx->cc_pending); 787 ctx->cc_sector++; 788 cond_resched(); 789 continue; 790 791 /* error */ 792 default: 793 atomic_dec(&ctx->cc_pending); 794 return r; 795 } 796 } 797 798 return 0; 799 } 800 801 /* 802 * Generate a new unfragmented bio with the given size 803 * This should never violate the device limitations 804 * May return a smaller bio when running out of pages, indicated by 805 * *out_of_pages set to 1. 806 */ 807 static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size, 808 unsigned *out_of_pages) 809 { 810 struct crypt_config *cc = io->cc; 811 struct bio *clone; 812 unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; 813 gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM; 814 unsigned i, len; 815 struct page *page; 816 817 clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs); 818 if (!clone) 819 return NULL; 820 821 clone_init(io, clone); 822 *out_of_pages = 0; 823 824 for (i = 0; i < nr_iovecs; i++) { 825 page = mempool_alloc(cc->page_pool, gfp_mask); 826 if (!page) { 827 *out_of_pages = 1; 828 break; 829 } 830 831 /* 832 * If additional pages cannot be allocated without waiting, 833 * return a partially-allocated bio. The caller will then try 834 * to allocate more bios while submitting this partial bio. 835 */ 836 gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT; 837 838 len = (size > PAGE_SIZE) ? PAGE_SIZE : size; 839 840 if (!bio_add_page(clone, page, len, 0)) { 841 mempool_free(page, cc->page_pool); 842 break; 843 } 844 845 size -= len; 846 } 847 848 if (!clone->bi_size) { 849 bio_put(clone); 850 return NULL; 851 } 852 853 return clone; 854 } 855 856 static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone) 857 { 858 unsigned int i; 859 struct bio_vec *bv; 860 861 bio_for_each_segment_all(bv, clone, i) { 862 BUG_ON(!bv->bv_page); 863 mempool_free(bv->bv_page, cc->page_pool); 864 bv->bv_page = NULL; 865 } 866 } 867 868 static struct dm_crypt_io *crypt_io_alloc(struct crypt_config *cc, 869 struct bio *bio, sector_t sector) 870 { 871 struct dm_crypt_io *io; 872 873 io = mempool_alloc(cc->io_pool, GFP_NOIO); 874 io->cc = cc; 875 io->base_bio = bio; 876 io->sector = sector; 877 io->error = 0; 878 io->base_io = NULL; 879 atomic_set(&io->io_pending, 0); 880 881 return io; 882 } 883 884 static void crypt_inc_pending(struct dm_crypt_io *io) 885 { 886 atomic_inc(&io->io_pending); 887 } 888 889 /* 890 * One of the bios was finished. Check for completion of 891 * the whole request and correctly clean up the buffer. 892 * If base_io is set, wait for the last fragment to complete. 893 */ 894 static void crypt_dec_pending(struct dm_crypt_io *io) 895 { 896 struct crypt_config *cc = io->cc; 897 struct bio *base_bio = io->base_bio; 898 struct dm_crypt_io *base_io = io->base_io; 899 int error = io->error; 900 901 if (!atomic_dec_and_test(&io->io_pending)) 902 return; 903 904 mempool_free(io, cc->io_pool); 905 906 if (likely(!base_io)) 907 bio_endio(base_bio, error); 908 else { 909 if (error && !base_io->error) 910 base_io->error = error; 911 crypt_dec_pending(base_io); 912 } 913 } 914 915 /* 916 * kcryptd/kcryptd_io: 917 * 918 * Needed because it would be very unwise to do decryption in an 919 * interrupt context. 920 * 921 * kcryptd performs the actual encryption or decryption. 922 * 923 * kcryptd_io performs the IO submission. 924 * 925 * They must be separated as otherwise the final stages could be 926 * starved by new requests which can block in the first stages due 927 * to memory allocation. 928 * 929 * The work is done per CPU global for all dm-crypt instances. 930 * They should not depend on each other and do not block. 931 */ 932 static void crypt_endio(struct bio *clone, int error) 933 { 934 struct dm_crypt_io *io = clone->bi_private; 935 struct crypt_config *cc = io->cc; 936 unsigned rw = bio_data_dir(clone); 937 938 if (unlikely(!bio_flagged(clone, BIO_UPTODATE) && !error)) 939 error = -EIO; 940 941 /* 942 * free the processed pages 943 */ 944 if (rw == WRITE) 945 crypt_free_buffer_pages(cc, clone); 946 947 bio_put(clone); 948 949 if (rw == READ && !error) { 950 kcryptd_queue_crypt(io); 951 return; 952 } 953 954 if (unlikely(error)) 955 io->error = error; 956 957 crypt_dec_pending(io); 958 } 959 960 static void clone_init(struct dm_crypt_io *io, struct bio *clone) 961 { 962 struct crypt_config *cc = io->cc; 963 964 clone->bi_private = io; 965 clone->bi_end_io = crypt_endio; 966 clone->bi_bdev = cc->dev->bdev; 967 clone->bi_rw = io->base_bio->bi_rw; 968 } 969 970 static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp) 971 { 972 struct crypt_config *cc = io->cc; 973 struct bio *base_bio = io->base_bio; 974 struct bio *clone; 975 976 /* 977 * The block layer might modify the bvec array, so always 978 * copy the required bvecs because we need the original 979 * one in order to decrypt the whole bio data *afterwards*. 980 */ 981 clone = bio_clone_bioset(base_bio, gfp, cc->bs); 982 if (!clone) 983 return 1; 984 985 crypt_inc_pending(io); 986 987 clone_init(io, clone); 988 clone->bi_sector = cc->start + io->sector; 989 990 generic_make_request(clone); 991 return 0; 992 } 993 994 static void kcryptd_io_write(struct dm_crypt_io *io) 995 { 996 struct bio *clone = io->ctx.bio_out; 997 generic_make_request(clone); 998 } 999 1000 static void kcryptd_io(struct work_struct *work) 1001 { 1002 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work); 1003 1004 if (bio_data_dir(io->base_bio) == READ) { 1005 crypt_inc_pending(io); 1006 if (kcryptd_io_read(io, GFP_NOIO)) 1007 io->error = -ENOMEM; 1008 crypt_dec_pending(io); 1009 } else 1010 kcryptd_io_write(io); 1011 } 1012 1013 static void kcryptd_queue_io(struct dm_crypt_io *io) 1014 { 1015 struct crypt_config *cc = io->cc; 1016 1017 INIT_WORK(&io->work, kcryptd_io); 1018 queue_work(cc->io_queue, &io->work); 1019 } 1020 1021 static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io, int async) 1022 { 1023 struct bio *clone = io->ctx.bio_out; 1024 struct crypt_config *cc = io->cc; 1025 1026 if (unlikely(io->error < 0)) { 1027 crypt_free_buffer_pages(cc, clone); 1028 bio_put(clone); 1029 crypt_dec_pending(io); 1030 return; 1031 } 1032 1033 /* crypt_convert should have filled the clone bio */ 1034 BUG_ON(io->ctx.idx_out < clone->bi_vcnt); 1035 1036 clone->bi_sector = cc->start + io->sector; 1037 1038 if (async) 1039 kcryptd_queue_io(io); 1040 else 1041 generic_make_request(clone); 1042 } 1043 1044 static void kcryptd_crypt_write_convert(struct dm_crypt_io *io) 1045 { 1046 struct crypt_config *cc = io->cc; 1047 struct bio *clone; 1048 struct dm_crypt_io *new_io; 1049 int crypt_finished; 1050 unsigned out_of_pages = 0; 1051 unsigned remaining = io->base_bio->bi_size; 1052 sector_t sector = io->sector; 1053 int r; 1054 1055 /* 1056 * Prevent io from disappearing until this function completes. 1057 */ 1058 crypt_inc_pending(io); 1059 crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, sector); 1060 1061 /* 1062 * The allocated buffers can be smaller than the whole bio, 1063 * so repeat the whole process until all the data can be handled. 1064 */ 1065 while (remaining) { 1066 clone = crypt_alloc_buffer(io, remaining, &out_of_pages); 1067 if (unlikely(!clone)) { 1068 io->error = -ENOMEM; 1069 break; 1070 } 1071 1072 io->ctx.bio_out = clone; 1073 io->ctx.idx_out = 0; 1074 1075 remaining -= clone->bi_size; 1076 sector += bio_sectors(clone); 1077 1078 crypt_inc_pending(io); 1079 1080 r = crypt_convert(cc, &io->ctx); 1081 if (r < 0) 1082 io->error = -EIO; 1083 1084 crypt_finished = atomic_dec_and_test(&io->ctx.cc_pending); 1085 1086 /* Encryption was already finished, submit io now */ 1087 if (crypt_finished) { 1088 kcryptd_crypt_write_io_submit(io, 0); 1089 1090 /* 1091 * If there was an error, do not try next fragments. 1092 * For async, error is processed in async handler. 1093 */ 1094 if (unlikely(r < 0)) 1095 break; 1096 1097 io->sector = sector; 1098 } 1099 1100 /* 1101 * Out of memory -> run queues 1102 * But don't wait if split was due to the io size restriction 1103 */ 1104 if (unlikely(out_of_pages)) 1105 congestion_wait(BLK_RW_ASYNC, HZ/100); 1106 1107 /* 1108 * With async crypto it is unsafe to share the crypto context 1109 * between fragments, so switch to a new dm_crypt_io structure. 1110 */ 1111 if (unlikely(!crypt_finished && remaining)) { 1112 new_io = crypt_io_alloc(io->cc, io->base_bio, 1113 sector); 1114 crypt_inc_pending(new_io); 1115 crypt_convert_init(cc, &new_io->ctx, NULL, 1116 io->base_bio, sector); 1117 new_io->ctx.idx_in = io->ctx.idx_in; 1118 new_io->ctx.offset_in = io->ctx.offset_in; 1119 1120 /* 1121 * Fragments after the first use the base_io 1122 * pending count. 1123 */ 1124 if (!io->base_io) 1125 new_io->base_io = io; 1126 else { 1127 new_io->base_io = io->base_io; 1128 crypt_inc_pending(io->base_io); 1129 crypt_dec_pending(io); 1130 } 1131 1132 io = new_io; 1133 } 1134 } 1135 1136 crypt_dec_pending(io); 1137 } 1138 1139 static void kcryptd_crypt_read_done(struct dm_crypt_io *io) 1140 { 1141 crypt_dec_pending(io); 1142 } 1143 1144 static void kcryptd_crypt_read_convert(struct dm_crypt_io *io) 1145 { 1146 struct crypt_config *cc = io->cc; 1147 int r = 0; 1148 1149 crypt_inc_pending(io); 1150 1151 crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio, 1152 io->sector); 1153 1154 r = crypt_convert(cc, &io->ctx); 1155 if (r < 0) 1156 io->error = -EIO; 1157 1158 if (atomic_dec_and_test(&io->ctx.cc_pending)) 1159 kcryptd_crypt_read_done(io); 1160 1161 crypt_dec_pending(io); 1162 } 1163 1164 static void kcryptd_async_done(struct crypto_async_request *async_req, 1165 int error) 1166 { 1167 struct dm_crypt_request *dmreq = async_req->data; 1168 struct convert_context *ctx = dmreq->ctx; 1169 struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx); 1170 struct crypt_config *cc = io->cc; 1171 1172 if (error == -EINPROGRESS) { 1173 complete(&ctx->restart); 1174 return; 1175 } 1176 1177 if (!error && cc->iv_gen_ops && cc->iv_gen_ops->post) 1178 error = cc->iv_gen_ops->post(cc, iv_of_dmreq(cc, dmreq), dmreq); 1179 1180 if (error < 0) 1181 io->error = -EIO; 1182 1183 mempool_free(req_of_dmreq(cc, dmreq), cc->req_pool); 1184 1185 if (!atomic_dec_and_test(&ctx->cc_pending)) 1186 return; 1187 1188 if (bio_data_dir(io->base_bio) == READ) 1189 kcryptd_crypt_read_done(io); 1190 else 1191 kcryptd_crypt_write_io_submit(io, 1); 1192 } 1193 1194 static void kcryptd_crypt(struct work_struct *work) 1195 { 1196 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work); 1197 1198 if (bio_data_dir(io->base_bio) == READ) 1199 kcryptd_crypt_read_convert(io); 1200 else 1201 kcryptd_crypt_write_convert(io); 1202 } 1203 1204 static void kcryptd_queue_crypt(struct dm_crypt_io *io) 1205 { 1206 struct crypt_config *cc = io->cc; 1207 1208 INIT_WORK(&io->work, kcryptd_crypt); 1209 queue_work(cc->crypt_queue, &io->work); 1210 } 1211 1212 /* 1213 * Decode key from its hex representation 1214 */ 1215 static int crypt_decode_key(u8 *key, char *hex, unsigned int size) 1216 { 1217 char buffer[3]; 1218 unsigned int i; 1219 1220 buffer[2] = '\0'; 1221 1222 for (i = 0; i < size; i++) { 1223 buffer[0] = *hex++; 1224 buffer[1] = *hex++; 1225 1226 if (kstrtou8(buffer, 16, &key[i])) 1227 return -EINVAL; 1228 } 1229 1230 if (*hex != '\0') 1231 return -EINVAL; 1232 1233 return 0; 1234 } 1235 1236 static void crypt_free_tfms(struct crypt_config *cc) 1237 { 1238 unsigned i; 1239 1240 if (!cc->tfms) 1241 return; 1242 1243 for (i = 0; i < cc->tfms_count; i++) 1244 if (cc->tfms[i] && !IS_ERR(cc->tfms[i])) { 1245 crypto_free_ablkcipher(cc->tfms[i]); 1246 cc->tfms[i] = NULL; 1247 } 1248 1249 kfree(cc->tfms); 1250 cc->tfms = NULL; 1251 } 1252 1253 static int crypt_alloc_tfms(struct crypt_config *cc, char *ciphermode) 1254 { 1255 unsigned i; 1256 int err; 1257 1258 cc->tfms = kmalloc(cc->tfms_count * sizeof(struct crypto_ablkcipher *), 1259 GFP_KERNEL); 1260 if (!cc->tfms) 1261 return -ENOMEM; 1262 1263 for (i = 0; i < cc->tfms_count; i++) { 1264 cc->tfms[i] = crypto_alloc_ablkcipher(ciphermode, 0, 0); 1265 if (IS_ERR(cc->tfms[i])) { 1266 err = PTR_ERR(cc->tfms[i]); 1267 crypt_free_tfms(cc); 1268 return err; 1269 } 1270 } 1271 1272 return 0; 1273 } 1274 1275 static int crypt_setkey_allcpus(struct crypt_config *cc) 1276 { 1277 unsigned subkey_size = cc->key_size >> ilog2(cc->tfms_count); 1278 int err = 0, i, r; 1279 1280 for (i = 0; i < cc->tfms_count; i++) { 1281 r = crypto_ablkcipher_setkey(cc->tfms[i], 1282 cc->key + (i * subkey_size), 1283 subkey_size); 1284 if (r) 1285 err = r; 1286 } 1287 1288 return err; 1289 } 1290 1291 static int crypt_set_key(struct crypt_config *cc, char *key) 1292 { 1293 int r = -EINVAL; 1294 int key_string_len = strlen(key); 1295 1296 /* The key size may not be changed. */ 1297 if (cc->key_size != (key_string_len >> 1)) 1298 goto out; 1299 1300 /* Hyphen (which gives a key_size of zero) means there is no key. */ 1301 if (!cc->key_size && strcmp(key, "-")) 1302 goto out; 1303 1304 if (cc->key_size && crypt_decode_key(cc->key, key, cc->key_size) < 0) 1305 goto out; 1306 1307 set_bit(DM_CRYPT_KEY_VALID, &cc->flags); 1308 1309 r = crypt_setkey_allcpus(cc); 1310 1311 out: 1312 /* Hex key string not needed after here, so wipe it. */ 1313 memset(key, '0', key_string_len); 1314 1315 return r; 1316 } 1317 1318 static int crypt_wipe_key(struct crypt_config *cc) 1319 { 1320 clear_bit(DM_CRYPT_KEY_VALID, &cc->flags); 1321 memset(&cc->key, 0, cc->key_size * sizeof(u8)); 1322 1323 return crypt_setkey_allcpus(cc); 1324 } 1325 1326 static void crypt_dtr(struct dm_target *ti) 1327 { 1328 struct crypt_config *cc = ti->private; 1329 struct crypt_cpu *cpu_cc; 1330 int cpu; 1331 1332 ti->private = NULL; 1333 1334 if (!cc) 1335 return; 1336 1337 if (cc->io_queue) 1338 destroy_workqueue(cc->io_queue); 1339 if (cc->crypt_queue) 1340 destroy_workqueue(cc->crypt_queue); 1341 1342 if (cc->cpu) 1343 for_each_possible_cpu(cpu) { 1344 cpu_cc = per_cpu_ptr(cc->cpu, cpu); 1345 if (cpu_cc->req) 1346 mempool_free(cpu_cc->req, cc->req_pool); 1347 } 1348 1349 crypt_free_tfms(cc); 1350 1351 if (cc->bs) 1352 bioset_free(cc->bs); 1353 1354 if (cc->page_pool) 1355 mempool_destroy(cc->page_pool); 1356 if (cc->req_pool) 1357 mempool_destroy(cc->req_pool); 1358 if (cc->io_pool) 1359 mempool_destroy(cc->io_pool); 1360 1361 if (cc->iv_gen_ops && cc->iv_gen_ops->dtr) 1362 cc->iv_gen_ops->dtr(cc); 1363 1364 if (cc->dev) 1365 dm_put_device(ti, cc->dev); 1366 1367 if (cc->cpu) 1368 free_percpu(cc->cpu); 1369 1370 kzfree(cc->cipher); 1371 kzfree(cc->cipher_string); 1372 1373 /* Must zero key material before freeing */ 1374 kzfree(cc); 1375 } 1376 1377 static int crypt_ctr_cipher(struct dm_target *ti, 1378 char *cipher_in, char *key) 1379 { 1380 struct crypt_config *cc = ti->private; 1381 char *tmp, *cipher, *chainmode, *ivmode, *ivopts, *keycount; 1382 char *cipher_api = NULL; 1383 int ret = -EINVAL; 1384 char dummy; 1385 1386 /* Convert to crypto api definition? */ 1387 if (strchr(cipher_in, '(')) { 1388 ti->error = "Bad cipher specification"; 1389 return -EINVAL; 1390 } 1391 1392 cc->cipher_string = kstrdup(cipher_in, GFP_KERNEL); 1393 if (!cc->cipher_string) 1394 goto bad_mem; 1395 1396 /* 1397 * Legacy dm-crypt cipher specification 1398 * cipher[:keycount]-mode-iv:ivopts 1399 */ 1400 tmp = cipher_in; 1401 keycount = strsep(&tmp, "-"); 1402 cipher = strsep(&keycount, ":"); 1403 1404 if (!keycount) 1405 cc->tfms_count = 1; 1406 else if (sscanf(keycount, "%u%c", &cc->tfms_count, &dummy) != 1 || 1407 !is_power_of_2(cc->tfms_count)) { 1408 ti->error = "Bad cipher key count specification"; 1409 return -EINVAL; 1410 } 1411 cc->key_parts = cc->tfms_count; 1412 1413 cc->cipher = kstrdup(cipher, GFP_KERNEL); 1414 if (!cc->cipher) 1415 goto bad_mem; 1416 1417 chainmode = strsep(&tmp, "-"); 1418 ivopts = strsep(&tmp, "-"); 1419 ivmode = strsep(&ivopts, ":"); 1420 1421 if (tmp) 1422 DMWARN("Ignoring unexpected additional cipher options"); 1423 1424 cc->cpu = __alloc_percpu(sizeof(*(cc->cpu)), 1425 __alignof__(struct crypt_cpu)); 1426 if (!cc->cpu) { 1427 ti->error = "Cannot allocate per cpu state"; 1428 goto bad_mem; 1429 } 1430 1431 /* 1432 * For compatibility with the original dm-crypt mapping format, if 1433 * only the cipher name is supplied, use cbc-plain. 1434 */ 1435 if (!chainmode || (!strcmp(chainmode, "plain") && !ivmode)) { 1436 chainmode = "cbc"; 1437 ivmode = "plain"; 1438 } 1439 1440 if (strcmp(chainmode, "ecb") && !ivmode) { 1441 ti->error = "IV mechanism required"; 1442 return -EINVAL; 1443 } 1444 1445 cipher_api = kmalloc(CRYPTO_MAX_ALG_NAME, GFP_KERNEL); 1446 if (!cipher_api) 1447 goto bad_mem; 1448 1449 ret = snprintf(cipher_api, CRYPTO_MAX_ALG_NAME, 1450 "%s(%s)", chainmode, cipher); 1451 if (ret < 0) { 1452 kfree(cipher_api); 1453 goto bad_mem; 1454 } 1455 1456 /* Allocate cipher */ 1457 ret = crypt_alloc_tfms(cc, cipher_api); 1458 if (ret < 0) { 1459 ti->error = "Error allocating crypto tfm"; 1460 goto bad; 1461 } 1462 1463 /* Initialize and set key */ 1464 ret = crypt_set_key(cc, key); 1465 if (ret < 0) { 1466 ti->error = "Error decoding and setting key"; 1467 goto bad; 1468 } 1469 1470 /* Initialize IV */ 1471 cc->iv_size = crypto_ablkcipher_ivsize(any_tfm(cc)); 1472 if (cc->iv_size) 1473 /* at least a 64 bit sector number should fit in our buffer */ 1474 cc->iv_size = max(cc->iv_size, 1475 (unsigned int)(sizeof(u64) / sizeof(u8))); 1476 else if (ivmode) { 1477 DMWARN("Selected cipher does not support IVs"); 1478 ivmode = NULL; 1479 } 1480 1481 /* Choose ivmode, see comments at iv code. */ 1482 if (ivmode == NULL) 1483 cc->iv_gen_ops = NULL; 1484 else if (strcmp(ivmode, "plain") == 0) 1485 cc->iv_gen_ops = &crypt_iv_plain_ops; 1486 else if (strcmp(ivmode, "plain64") == 0) 1487 cc->iv_gen_ops = &crypt_iv_plain64_ops; 1488 else if (strcmp(ivmode, "essiv") == 0) 1489 cc->iv_gen_ops = &crypt_iv_essiv_ops; 1490 else if (strcmp(ivmode, "benbi") == 0) 1491 cc->iv_gen_ops = &crypt_iv_benbi_ops; 1492 else if (strcmp(ivmode, "null") == 0) 1493 cc->iv_gen_ops = &crypt_iv_null_ops; 1494 else if (strcmp(ivmode, "lmk") == 0) { 1495 cc->iv_gen_ops = &crypt_iv_lmk_ops; 1496 /* Version 2 and 3 is recognised according 1497 * to length of provided multi-key string. 1498 * If present (version 3), last key is used as IV seed. 1499 */ 1500 if (cc->key_size % cc->key_parts) 1501 cc->key_parts++; 1502 } else { 1503 ret = -EINVAL; 1504 ti->error = "Invalid IV mode"; 1505 goto bad; 1506 } 1507 1508 /* Allocate IV */ 1509 if (cc->iv_gen_ops && cc->iv_gen_ops->ctr) { 1510 ret = cc->iv_gen_ops->ctr(cc, ti, ivopts); 1511 if (ret < 0) { 1512 ti->error = "Error creating IV"; 1513 goto bad; 1514 } 1515 } 1516 1517 /* Initialize IV (set keys for ESSIV etc) */ 1518 if (cc->iv_gen_ops && cc->iv_gen_ops->init) { 1519 ret = cc->iv_gen_ops->init(cc); 1520 if (ret < 0) { 1521 ti->error = "Error initialising IV"; 1522 goto bad; 1523 } 1524 } 1525 1526 ret = 0; 1527 bad: 1528 kfree(cipher_api); 1529 return ret; 1530 1531 bad_mem: 1532 ti->error = "Cannot allocate cipher strings"; 1533 return -ENOMEM; 1534 } 1535 1536 /* 1537 * Construct an encryption mapping: 1538 * <cipher> <key> <iv_offset> <dev_path> <start> 1539 */ 1540 static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv) 1541 { 1542 struct crypt_config *cc; 1543 unsigned int key_size, opt_params; 1544 unsigned long long tmpll; 1545 int ret; 1546 struct dm_arg_set as; 1547 const char *opt_string; 1548 char dummy; 1549 1550 static struct dm_arg _args[] = { 1551 {0, 1, "Invalid number of feature args"}, 1552 }; 1553 1554 if (argc < 5) { 1555 ti->error = "Not enough arguments"; 1556 return -EINVAL; 1557 } 1558 1559 key_size = strlen(argv[1]) >> 1; 1560 1561 cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL); 1562 if (!cc) { 1563 ti->error = "Cannot allocate encryption context"; 1564 return -ENOMEM; 1565 } 1566 cc->key_size = key_size; 1567 1568 ti->private = cc; 1569 ret = crypt_ctr_cipher(ti, argv[0], argv[1]); 1570 if (ret < 0) 1571 goto bad; 1572 1573 ret = -ENOMEM; 1574 cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool); 1575 if (!cc->io_pool) { 1576 ti->error = "Cannot allocate crypt io mempool"; 1577 goto bad; 1578 } 1579 1580 cc->dmreq_start = sizeof(struct ablkcipher_request); 1581 cc->dmreq_start += crypto_ablkcipher_reqsize(any_tfm(cc)); 1582 cc->dmreq_start = ALIGN(cc->dmreq_start, crypto_tfm_ctx_alignment()); 1583 cc->dmreq_start += crypto_ablkcipher_alignmask(any_tfm(cc)) & 1584 ~(crypto_tfm_ctx_alignment() - 1); 1585 1586 cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start + 1587 sizeof(struct dm_crypt_request) + cc->iv_size); 1588 if (!cc->req_pool) { 1589 ti->error = "Cannot allocate crypt request mempool"; 1590 goto bad; 1591 } 1592 1593 cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0); 1594 if (!cc->page_pool) { 1595 ti->error = "Cannot allocate page mempool"; 1596 goto bad; 1597 } 1598 1599 cc->bs = bioset_create(MIN_IOS, 0); 1600 if (!cc->bs) { 1601 ti->error = "Cannot allocate crypt bioset"; 1602 goto bad; 1603 } 1604 1605 ret = -EINVAL; 1606 if (sscanf(argv[2], "%llu%c", &tmpll, &dummy) != 1) { 1607 ti->error = "Invalid iv_offset sector"; 1608 goto bad; 1609 } 1610 cc->iv_offset = tmpll; 1611 1612 if (dm_get_device(ti, argv[3], dm_table_get_mode(ti->table), &cc->dev)) { 1613 ti->error = "Device lookup failed"; 1614 goto bad; 1615 } 1616 1617 if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1) { 1618 ti->error = "Invalid device sector"; 1619 goto bad; 1620 } 1621 cc->start = tmpll; 1622 1623 argv += 5; 1624 argc -= 5; 1625 1626 /* Optional parameters */ 1627 if (argc) { 1628 as.argc = argc; 1629 as.argv = argv; 1630 1631 ret = dm_read_arg_group(_args, &as, &opt_params, &ti->error); 1632 if (ret) 1633 goto bad; 1634 1635 opt_string = dm_shift_arg(&as); 1636 1637 if (opt_params == 1 && opt_string && 1638 !strcasecmp(opt_string, "allow_discards")) 1639 ti->num_discard_bios = 1; 1640 else if (opt_params) { 1641 ret = -EINVAL; 1642 ti->error = "Invalid feature arguments"; 1643 goto bad; 1644 } 1645 } 1646 1647 ret = -ENOMEM; 1648 cc->io_queue = alloc_workqueue("kcryptd_io", WQ_MEM_RECLAIM, 1); 1649 if (!cc->io_queue) { 1650 ti->error = "Couldn't create kcryptd io queue"; 1651 goto bad; 1652 } 1653 1654 cc->crypt_queue = alloc_workqueue("kcryptd", 1655 WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM, 1); 1656 if (!cc->crypt_queue) { 1657 ti->error = "Couldn't create kcryptd queue"; 1658 goto bad; 1659 } 1660 1661 ti->num_flush_bios = 1; 1662 ti->discard_zeroes_data_unsupported = true; 1663 1664 return 0; 1665 1666 bad: 1667 crypt_dtr(ti); 1668 return ret; 1669 } 1670 1671 static int crypt_map(struct dm_target *ti, struct bio *bio) 1672 { 1673 struct dm_crypt_io *io; 1674 struct crypt_config *cc = ti->private; 1675 1676 /* 1677 * If bio is REQ_FLUSH or REQ_DISCARD, just bypass crypt queues. 1678 * - for REQ_FLUSH device-mapper core ensures that no IO is in-flight 1679 * - for REQ_DISCARD caller must use flush if IO ordering matters 1680 */ 1681 if (unlikely(bio->bi_rw & (REQ_FLUSH | REQ_DISCARD))) { 1682 bio->bi_bdev = cc->dev->bdev; 1683 if (bio_sectors(bio)) 1684 bio->bi_sector = cc->start + dm_target_offset(ti, bio->bi_sector); 1685 return DM_MAPIO_REMAPPED; 1686 } 1687 1688 io = crypt_io_alloc(cc, bio, dm_target_offset(ti, bio->bi_sector)); 1689 1690 if (bio_data_dir(io->base_bio) == READ) { 1691 if (kcryptd_io_read(io, GFP_NOWAIT)) 1692 kcryptd_queue_io(io); 1693 } else 1694 kcryptd_queue_crypt(io); 1695 1696 return DM_MAPIO_SUBMITTED; 1697 } 1698 1699 static void crypt_status(struct dm_target *ti, status_type_t type, 1700 unsigned status_flags, char *result, unsigned maxlen) 1701 { 1702 struct crypt_config *cc = ti->private; 1703 unsigned i, sz = 0; 1704 1705 switch (type) { 1706 case STATUSTYPE_INFO: 1707 result[0] = '\0'; 1708 break; 1709 1710 case STATUSTYPE_TABLE: 1711 DMEMIT("%s ", cc->cipher_string); 1712 1713 if (cc->key_size > 0) 1714 for (i = 0; i < cc->key_size; i++) 1715 DMEMIT("%02x", cc->key[i]); 1716 else 1717 DMEMIT("-"); 1718 1719 DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset, 1720 cc->dev->name, (unsigned long long)cc->start); 1721 1722 if (ti->num_discard_bios) 1723 DMEMIT(" 1 allow_discards"); 1724 1725 break; 1726 } 1727 } 1728 1729 static void crypt_postsuspend(struct dm_target *ti) 1730 { 1731 struct crypt_config *cc = ti->private; 1732 1733 set_bit(DM_CRYPT_SUSPENDED, &cc->flags); 1734 } 1735 1736 static int crypt_preresume(struct dm_target *ti) 1737 { 1738 struct crypt_config *cc = ti->private; 1739 1740 if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) { 1741 DMERR("aborting resume - crypt key is not set."); 1742 return -EAGAIN; 1743 } 1744 1745 return 0; 1746 } 1747 1748 static void crypt_resume(struct dm_target *ti) 1749 { 1750 struct crypt_config *cc = ti->private; 1751 1752 clear_bit(DM_CRYPT_SUSPENDED, &cc->flags); 1753 } 1754 1755 /* Message interface 1756 * key set <key> 1757 * key wipe 1758 */ 1759 static int crypt_message(struct dm_target *ti, unsigned argc, char **argv) 1760 { 1761 struct crypt_config *cc = ti->private; 1762 int ret = -EINVAL; 1763 1764 if (argc < 2) 1765 goto error; 1766 1767 if (!strcasecmp(argv[0], "key")) { 1768 if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) { 1769 DMWARN("not suspended during key manipulation."); 1770 return -EINVAL; 1771 } 1772 if (argc == 3 && !strcasecmp(argv[1], "set")) { 1773 ret = crypt_set_key(cc, argv[2]); 1774 if (ret) 1775 return ret; 1776 if (cc->iv_gen_ops && cc->iv_gen_ops->init) 1777 ret = cc->iv_gen_ops->init(cc); 1778 return ret; 1779 } 1780 if (argc == 2 && !strcasecmp(argv[1], "wipe")) { 1781 if (cc->iv_gen_ops && cc->iv_gen_ops->wipe) { 1782 ret = cc->iv_gen_ops->wipe(cc); 1783 if (ret) 1784 return ret; 1785 } 1786 return crypt_wipe_key(cc); 1787 } 1788 } 1789 1790 error: 1791 DMWARN("unrecognised message received."); 1792 return -EINVAL; 1793 } 1794 1795 static int crypt_merge(struct dm_target *ti, struct bvec_merge_data *bvm, 1796 struct bio_vec *biovec, int max_size) 1797 { 1798 struct crypt_config *cc = ti->private; 1799 struct request_queue *q = bdev_get_queue(cc->dev->bdev); 1800 1801 if (!q->merge_bvec_fn) 1802 return max_size; 1803 1804 bvm->bi_bdev = cc->dev->bdev; 1805 bvm->bi_sector = cc->start + dm_target_offset(ti, bvm->bi_sector); 1806 1807 return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); 1808 } 1809 1810 static int crypt_iterate_devices(struct dm_target *ti, 1811 iterate_devices_callout_fn fn, void *data) 1812 { 1813 struct crypt_config *cc = ti->private; 1814 1815 return fn(ti, cc->dev, cc->start, ti->len, data); 1816 } 1817 1818 static struct target_type crypt_target = { 1819 .name = "crypt", 1820 .version = {1, 12, 1}, 1821 .module = THIS_MODULE, 1822 .ctr = crypt_ctr, 1823 .dtr = crypt_dtr, 1824 .map = crypt_map, 1825 .status = crypt_status, 1826 .postsuspend = crypt_postsuspend, 1827 .preresume = crypt_preresume, 1828 .resume = crypt_resume, 1829 .message = crypt_message, 1830 .merge = crypt_merge, 1831 .iterate_devices = crypt_iterate_devices, 1832 }; 1833 1834 static int __init dm_crypt_init(void) 1835 { 1836 int r; 1837 1838 _crypt_io_pool = KMEM_CACHE(dm_crypt_io, 0); 1839 if (!_crypt_io_pool) 1840 return -ENOMEM; 1841 1842 r = dm_register_target(&crypt_target); 1843 if (r < 0) { 1844 DMERR("register failed %d", r); 1845 kmem_cache_destroy(_crypt_io_pool); 1846 } 1847 1848 return r; 1849 } 1850 1851 static void __exit dm_crypt_exit(void) 1852 { 1853 dm_unregister_target(&crypt_target); 1854 kmem_cache_destroy(_crypt_io_pool); 1855 } 1856 1857 module_init(dm_crypt_init); 1858 module_exit(dm_crypt_exit); 1859 1860 MODULE_AUTHOR("Christophe Saout <christophe@saout.de>"); 1861 MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption"); 1862 MODULE_LICENSE("GPL"); 1863