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 for (i = 0; i < clone->bi_vcnt; i++) { 862 bv = bio_iovec_idx(clone, i); 863 BUG_ON(!bv->bv_page); 864 mempool_free(bv->bv_page, cc->page_pool); 865 bv->bv_page = NULL; 866 } 867 } 868 869 static struct dm_crypt_io *crypt_io_alloc(struct crypt_config *cc, 870 struct bio *bio, sector_t sector) 871 { 872 struct dm_crypt_io *io; 873 874 io = mempool_alloc(cc->io_pool, GFP_NOIO); 875 io->cc = cc; 876 io->base_bio = bio; 877 io->sector = sector; 878 io->error = 0; 879 io->base_io = NULL; 880 atomic_set(&io->io_pending, 0); 881 882 return io; 883 } 884 885 static void crypt_inc_pending(struct dm_crypt_io *io) 886 { 887 atomic_inc(&io->io_pending); 888 } 889 890 /* 891 * One of the bios was finished. Check for completion of 892 * the whole request and correctly clean up the buffer. 893 * If base_io is set, wait for the last fragment to complete. 894 */ 895 static void crypt_dec_pending(struct dm_crypt_io *io) 896 { 897 struct crypt_config *cc = io->cc; 898 struct bio *base_bio = io->base_bio; 899 struct dm_crypt_io *base_io = io->base_io; 900 int error = io->error; 901 902 if (!atomic_dec_and_test(&io->io_pending)) 903 return; 904 905 mempool_free(io, cc->io_pool); 906 907 if (likely(!base_io)) 908 bio_endio(base_bio, error); 909 else { 910 if (error && !base_io->error) 911 base_io->error = error; 912 crypt_dec_pending(base_io); 913 } 914 } 915 916 /* 917 * kcryptd/kcryptd_io: 918 * 919 * Needed because it would be very unwise to do decryption in an 920 * interrupt context. 921 * 922 * kcryptd performs the actual encryption or decryption. 923 * 924 * kcryptd_io performs the IO submission. 925 * 926 * They must be separated as otherwise the final stages could be 927 * starved by new requests which can block in the first stages due 928 * to memory allocation. 929 * 930 * The work is done per CPU global for all dm-crypt instances. 931 * They should not depend on each other and do not block. 932 */ 933 static void crypt_endio(struct bio *clone, int error) 934 { 935 struct dm_crypt_io *io = clone->bi_private; 936 struct crypt_config *cc = io->cc; 937 unsigned rw = bio_data_dir(clone); 938 939 if (unlikely(!bio_flagged(clone, BIO_UPTODATE) && !error)) 940 error = -EIO; 941 942 /* 943 * free the processed pages 944 */ 945 if (rw == WRITE) 946 crypt_free_buffer_pages(cc, clone); 947 948 bio_put(clone); 949 950 if (rw == READ && !error) { 951 kcryptd_queue_crypt(io); 952 return; 953 } 954 955 if (unlikely(error)) 956 io->error = error; 957 958 crypt_dec_pending(io); 959 } 960 961 static void clone_init(struct dm_crypt_io *io, struct bio *clone) 962 { 963 struct crypt_config *cc = io->cc; 964 965 clone->bi_private = io; 966 clone->bi_end_io = crypt_endio; 967 clone->bi_bdev = cc->dev->bdev; 968 clone->bi_rw = io->base_bio->bi_rw; 969 } 970 971 static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp) 972 { 973 struct crypt_config *cc = io->cc; 974 struct bio *base_bio = io->base_bio; 975 struct bio *clone; 976 977 /* 978 * The block layer might modify the bvec array, so always 979 * copy the required bvecs because we need the original 980 * one in order to decrypt the whole bio data *afterwards*. 981 */ 982 clone = bio_clone_bioset(base_bio, gfp, cc->bs); 983 if (!clone) 984 return 1; 985 986 crypt_inc_pending(io); 987 988 clone_init(io, clone); 989 clone->bi_sector = cc->start + io->sector; 990 991 generic_make_request(clone); 992 return 0; 993 } 994 995 static void kcryptd_io_write(struct dm_crypt_io *io) 996 { 997 struct bio *clone = io->ctx.bio_out; 998 generic_make_request(clone); 999 } 1000 1001 static void kcryptd_io(struct work_struct *work) 1002 { 1003 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work); 1004 1005 if (bio_data_dir(io->base_bio) == READ) { 1006 crypt_inc_pending(io); 1007 if (kcryptd_io_read(io, GFP_NOIO)) 1008 io->error = -ENOMEM; 1009 crypt_dec_pending(io); 1010 } else 1011 kcryptd_io_write(io); 1012 } 1013 1014 static void kcryptd_queue_io(struct dm_crypt_io *io) 1015 { 1016 struct crypt_config *cc = io->cc; 1017 1018 INIT_WORK(&io->work, kcryptd_io); 1019 queue_work(cc->io_queue, &io->work); 1020 } 1021 1022 static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io, int async) 1023 { 1024 struct bio *clone = io->ctx.bio_out; 1025 struct crypt_config *cc = io->cc; 1026 1027 if (unlikely(io->error < 0)) { 1028 crypt_free_buffer_pages(cc, clone); 1029 bio_put(clone); 1030 crypt_dec_pending(io); 1031 return; 1032 } 1033 1034 /* crypt_convert should have filled the clone bio */ 1035 BUG_ON(io->ctx.idx_out < clone->bi_vcnt); 1036 1037 clone->bi_sector = cc->start + io->sector; 1038 1039 if (async) 1040 kcryptd_queue_io(io); 1041 else 1042 generic_make_request(clone); 1043 } 1044 1045 static void kcryptd_crypt_write_convert(struct dm_crypt_io *io) 1046 { 1047 struct crypt_config *cc = io->cc; 1048 struct bio *clone; 1049 struct dm_crypt_io *new_io; 1050 int crypt_finished; 1051 unsigned out_of_pages = 0; 1052 unsigned remaining = io->base_bio->bi_size; 1053 sector_t sector = io->sector; 1054 int r; 1055 1056 /* 1057 * Prevent io from disappearing until this function completes. 1058 */ 1059 crypt_inc_pending(io); 1060 crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, sector); 1061 1062 /* 1063 * The allocated buffers can be smaller than the whole bio, 1064 * so repeat the whole process until all the data can be handled. 1065 */ 1066 while (remaining) { 1067 clone = crypt_alloc_buffer(io, remaining, &out_of_pages); 1068 if (unlikely(!clone)) { 1069 io->error = -ENOMEM; 1070 break; 1071 } 1072 1073 io->ctx.bio_out = clone; 1074 io->ctx.idx_out = 0; 1075 1076 remaining -= clone->bi_size; 1077 sector += bio_sectors(clone); 1078 1079 crypt_inc_pending(io); 1080 1081 r = crypt_convert(cc, &io->ctx); 1082 if (r < 0) 1083 io->error = -EIO; 1084 1085 crypt_finished = atomic_dec_and_test(&io->ctx.cc_pending); 1086 1087 /* Encryption was already finished, submit io now */ 1088 if (crypt_finished) { 1089 kcryptd_crypt_write_io_submit(io, 0); 1090 1091 /* 1092 * If there was an error, do not try next fragments. 1093 * For async, error is processed in async handler. 1094 */ 1095 if (unlikely(r < 0)) 1096 break; 1097 1098 io->sector = sector; 1099 } 1100 1101 /* 1102 * Out of memory -> run queues 1103 * But don't wait if split was due to the io size restriction 1104 */ 1105 if (unlikely(out_of_pages)) 1106 congestion_wait(BLK_RW_ASYNC, HZ/100); 1107 1108 /* 1109 * With async crypto it is unsafe to share the crypto context 1110 * between fragments, so switch to a new dm_crypt_io structure. 1111 */ 1112 if (unlikely(!crypt_finished && remaining)) { 1113 new_io = crypt_io_alloc(io->cc, io->base_bio, 1114 sector); 1115 crypt_inc_pending(new_io); 1116 crypt_convert_init(cc, &new_io->ctx, NULL, 1117 io->base_bio, sector); 1118 new_io->ctx.idx_in = io->ctx.idx_in; 1119 new_io->ctx.offset_in = io->ctx.offset_in; 1120 1121 /* 1122 * Fragments after the first use the base_io 1123 * pending count. 1124 */ 1125 if (!io->base_io) 1126 new_io->base_io = io; 1127 else { 1128 new_io->base_io = io->base_io; 1129 crypt_inc_pending(io->base_io); 1130 crypt_dec_pending(io); 1131 } 1132 1133 io = new_io; 1134 } 1135 } 1136 1137 crypt_dec_pending(io); 1138 } 1139 1140 static void kcryptd_crypt_read_done(struct dm_crypt_io *io) 1141 { 1142 crypt_dec_pending(io); 1143 } 1144 1145 static void kcryptd_crypt_read_convert(struct dm_crypt_io *io) 1146 { 1147 struct crypt_config *cc = io->cc; 1148 int r = 0; 1149 1150 crypt_inc_pending(io); 1151 1152 crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio, 1153 io->sector); 1154 1155 r = crypt_convert(cc, &io->ctx); 1156 if (r < 0) 1157 io->error = -EIO; 1158 1159 if (atomic_dec_and_test(&io->ctx.cc_pending)) 1160 kcryptd_crypt_read_done(io); 1161 1162 crypt_dec_pending(io); 1163 } 1164 1165 static void kcryptd_async_done(struct crypto_async_request *async_req, 1166 int error) 1167 { 1168 struct dm_crypt_request *dmreq = async_req->data; 1169 struct convert_context *ctx = dmreq->ctx; 1170 struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx); 1171 struct crypt_config *cc = io->cc; 1172 1173 if (error == -EINPROGRESS) { 1174 complete(&ctx->restart); 1175 return; 1176 } 1177 1178 if (!error && cc->iv_gen_ops && cc->iv_gen_ops->post) 1179 error = cc->iv_gen_ops->post(cc, iv_of_dmreq(cc, dmreq), dmreq); 1180 1181 if (error < 0) 1182 io->error = -EIO; 1183 1184 mempool_free(req_of_dmreq(cc, dmreq), cc->req_pool); 1185 1186 if (!atomic_dec_and_test(&ctx->cc_pending)) 1187 return; 1188 1189 if (bio_data_dir(io->base_bio) == READ) 1190 kcryptd_crypt_read_done(io); 1191 else 1192 kcryptd_crypt_write_io_submit(io, 1); 1193 } 1194 1195 static void kcryptd_crypt(struct work_struct *work) 1196 { 1197 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work); 1198 1199 if (bio_data_dir(io->base_bio) == READ) 1200 kcryptd_crypt_read_convert(io); 1201 else 1202 kcryptd_crypt_write_convert(io); 1203 } 1204 1205 static void kcryptd_queue_crypt(struct dm_crypt_io *io) 1206 { 1207 struct crypt_config *cc = io->cc; 1208 1209 INIT_WORK(&io->work, kcryptd_crypt); 1210 queue_work(cc->crypt_queue, &io->work); 1211 } 1212 1213 /* 1214 * Decode key from its hex representation 1215 */ 1216 static int crypt_decode_key(u8 *key, char *hex, unsigned int size) 1217 { 1218 char buffer[3]; 1219 unsigned int i; 1220 1221 buffer[2] = '\0'; 1222 1223 for (i = 0; i < size; i++) { 1224 buffer[0] = *hex++; 1225 buffer[1] = *hex++; 1226 1227 if (kstrtou8(buffer, 16, &key[i])) 1228 return -EINVAL; 1229 } 1230 1231 if (*hex != '\0') 1232 return -EINVAL; 1233 1234 return 0; 1235 } 1236 1237 static void crypt_free_tfms(struct crypt_config *cc) 1238 { 1239 unsigned i; 1240 1241 if (!cc->tfms) 1242 return; 1243 1244 for (i = 0; i < cc->tfms_count; i++) 1245 if (cc->tfms[i] && !IS_ERR(cc->tfms[i])) { 1246 crypto_free_ablkcipher(cc->tfms[i]); 1247 cc->tfms[i] = NULL; 1248 } 1249 1250 kfree(cc->tfms); 1251 cc->tfms = NULL; 1252 } 1253 1254 static int crypt_alloc_tfms(struct crypt_config *cc, char *ciphermode) 1255 { 1256 unsigned i; 1257 int err; 1258 1259 cc->tfms = kmalloc(cc->tfms_count * sizeof(struct crypto_ablkcipher *), 1260 GFP_KERNEL); 1261 if (!cc->tfms) 1262 return -ENOMEM; 1263 1264 for (i = 0; i < cc->tfms_count; i++) { 1265 cc->tfms[i] = crypto_alloc_ablkcipher(ciphermode, 0, 0); 1266 if (IS_ERR(cc->tfms[i])) { 1267 err = PTR_ERR(cc->tfms[i]); 1268 crypt_free_tfms(cc); 1269 return err; 1270 } 1271 } 1272 1273 return 0; 1274 } 1275 1276 static int crypt_setkey_allcpus(struct crypt_config *cc) 1277 { 1278 unsigned subkey_size = cc->key_size >> ilog2(cc->tfms_count); 1279 int err = 0, i, r; 1280 1281 for (i = 0; i < cc->tfms_count; i++) { 1282 r = crypto_ablkcipher_setkey(cc->tfms[i], 1283 cc->key + (i * subkey_size), 1284 subkey_size); 1285 if (r) 1286 err = r; 1287 } 1288 1289 return err; 1290 } 1291 1292 static int crypt_set_key(struct crypt_config *cc, char *key) 1293 { 1294 int r = -EINVAL; 1295 int key_string_len = strlen(key); 1296 1297 /* The key size may not be changed. */ 1298 if (cc->key_size != (key_string_len >> 1)) 1299 goto out; 1300 1301 /* Hyphen (which gives a key_size of zero) means there is no key. */ 1302 if (!cc->key_size && strcmp(key, "-")) 1303 goto out; 1304 1305 if (cc->key_size && crypt_decode_key(cc->key, key, cc->key_size) < 0) 1306 goto out; 1307 1308 set_bit(DM_CRYPT_KEY_VALID, &cc->flags); 1309 1310 r = crypt_setkey_allcpus(cc); 1311 1312 out: 1313 /* Hex key string not needed after here, so wipe it. */ 1314 memset(key, '0', key_string_len); 1315 1316 return r; 1317 } 1318 1319 static int crypt_wipe_key(struct crypt_config *cc) 1320 { 1321 clear_bit(DM_CRYPT_KEY_VALID, &cc->flags); 1322 memset(&cc->key, 0, cc->key_size * sizeof(u8)); 1323 1324 return crypt_setkey_allcpus(cc); 1325 } 1326 1327 static void crypt_dtr(struct dm_target *ti) 1328 { 1329 struct crypt_config *cc = ti->private; 1330 struct crypt_cpu *cpu_cc; 1331 int cpu; 1332 1333 ti->private = NULL; 1334 1335 if (!cc) 1336 return; 1337 1338 if (cc->io_queue) 1339 destroy_workqueue(cc->io_queue); 1340 if (cc->crypt_queue) 1341 destroy_workqueue(cc->crypt_queue); 1342 1343 if (cc->cpu) 1344 for_each_possible_cpu(cpu) { 1345 cpu_cc = per_cpu_ptr(cc->cpu, cpu); 1346 if (cpu_cc->req) 1347 mempool_free(cpu_cc->req, cc->req_pool); 1348 } 1349 1350 crypt_free_tfms(cc); 1351 1352 if (cc->bs) 1353 bioset_free(cc->bs); 1354 1355 if (cc->page_pool) 1356 mempool_destroy(cc->page_pool); 1357 if (cc->req_pool) 1358 mempool_destroy(cc->req_pool); 1359 if (cc->io_pool) 1360 mempool_destroy(cc->io_pool); 1361 1362 if (cc->iv_gen_ops && cc->iv_gen_ops->dtr) 1363 cc->iv_gen_ops->dtr(cc); 1364 1365 if (cc->dev) 1366 dm_put_device(ti, cc->dev); 1367 1368 if (cc->cpu) 1369 free_percpu(cc->cpu); 1370 1371 kzfree(cc->cipher); 1372 kzfree(cc->cipher_string); 1373 1374 /* Must zero key material before freeing */ 1375 kzfree(cc); 1376 } 1377 1378 static int crypt_ctr_cipher(struct dm_target *ti, 1379 char *cipher_in, char *key) 1380 { 1381 struct crypt_config *cc = ti->private; 1382 char *tmp, *cipher, *chainmode, *ivmode, *ivopts, *keycount; 1383 char *cipher_api = NULL; 1384 int ret = -EINVAL; 1385 char dummy; 1386 1387 /* Convert to crypto api definition? */ 1388 if (strchr(cipher_in, '(')) { 1389 ti->error = "Bad cipher specification"; 1390 return -EINVAL; 1391 } 1392 1393 cc->cipher_string = kstrdup(cipher_in, GFP_KERNEL); 1394 if (!cc->cipher_string) 1395 goto bad_mem; 1396 1397 /* 1398 * Legacy dm-crypt cipher specification 1399 * cipher[:keycount]-mode-iv:ivopts 1400 */ 1401 tmp = cipher_in; 1402 keycount = strsep(&tmp, "-"); 1403 cipher = strsep(&keycount, ":"); 1404 1405 if (!keycount) 1406 cc->tfms_count = 1; 1407 else if (sscanf(keycount, "%u%c", &cc->tfms_count, &dummy) != 1 || 1408 !is_power_of_2(cc->tfms_count)) { 1409 ti->error = "Bad cipher key count specification"; 1410 return -EINVAL; 1411 } 1412 cc->key_parts = cc->tfms_count; 1413 1414 cc->cipher = kstrdup(cipher, GFP_KERNEL); 1415 if (!cc->cipher) 1416 goto bad_mem; 1417 1418 chainmode = strsep(&tmp, "-"); 1419 ivopts = strsep(&tmp, "-"); 1420 ivmode = strsep(&ivopts, ":"); 1421 1422 if (tmp) 1423 DMWARN("Ignoring unexpected additional cipher options"); 1424 1425 cc->cpu = __alloc_percpu(sizeof(*(cc->cpu)), 1426 __alignof__(struct crypt_cpu)); 1427 if (!cc->cpu) { 1428 ti->error = "Cannot allocate per cpu state"; 1429 goto bad_mem; 1430 } 1431 1432 /* 1433 * For compatibility with the original dm-crypt mapping format, if 1434 * only the cipher name is supplied, use cbc-plain. 1435 */ 1436 if (!chainmode || (!strcmp(chainmode, "plain") && !ivmode)) { 1437 chainmode = "cbc"; 1438 ivmode = "plain"; 1439 } 1440 1441 if (strcmp(chainmode, "ecb") && !ivmode) { 1442 ti->error = "IV mechanism required"; 1443 return -EINVAL; 1444 } 1445 1446 cipher_api = kmalloc(CRYPTO_MAX_ALG_NAME, GFP_KERNEL); 1447 if (!cipher_api) 1448 goto bad_mem; 1449 1450 ret = snprintf(cipher_api, CRYPTO_MAX_ALG_NAME, 1451 "%s(%s)", chainmode, cipher); 1452 if (ret < 0) { 1453 kfree(cipher_api); 1454 goto bad_mem; 1455 } 1456 1457 /* Allocate cipher */ 1458 ret = crypt_alloc_tfms(cc, cipher_api); 1459 if (ret < 0) { 1460 ti->error = "Error allocating crypto tfm"; 1461 goto bad; 1462 } 1463 1464 /* Initialize and set key */ 1465 ret = crypt_set_key(cc, key); 1466 if (ret < 0) { 1467 ti->error = "Error decoding and setting key"; 1468 goto bad; 1469 } 1470 1471 /* Initialize IV */ 1472 cc->iv_size = crypto_ablkcipher_ivsize(any_tfm(cc)); 1473 if (cc->iv_size) 1474 /* at least a 64 bit sector number should fit in our buffer */ 1475 cc->iv_size = max(cc->iv_size, 1476 (unsigned int)(sizeof(u64) / sizeof(u8))); 1477 else if (ivmode) { 1478 DMWARN("Selected cipher does not support IVs"); 1479 ivmode = NULL; 1480 } 1481 1482 /* Choose ivmode, see comments at iv code. */ 1483 if (ivmode == NULL) 1484 cc->iv_gen_ops = NULL; 1485 else if (strcmp(ivmode, "plain") == 0) 1486 cc->iv_gen_ops = &crypt_iv_plain_ops; 1487 else if (strcmp(ivmode, "plain64") == 0) 1488 cc->iv_gen_ops = &crypt_iv_plain64_ops; 1489 else if (strcmp(ivmode, "essiv") == 0) 1490 cc->iv_gen_ops = &crypt_iv_essiv_ops; 1491 else if (strcmp(ivmode, "benbi") == 0) 1492 cc->iv_gen_ops = &crypt_iv_benbi_ops; 1493 else if (strcmp(ivmode, "null") == 0) 1494 cc->iv_gen_ops = &crypt_iv_null_ops; 1495 else if (strcmp(ivmode, "lmk") == 0) { 1496 cc->iv_gen_ops = &crypt_iv_lmk_ops; 1497 /* Version 2 and 3 is recognised according 1498 * to length of provided multi-key string. 1499 * If present (version 3), last key is used as IV seed. 1500 */ 1501 if (cc->key_size % cc->key_parts) 1502 cc->key_parts++; 1503 } else { 1504 ret = -EINVAL; 1505 ti->error = "Invalid IV mode"; 1506 goto bad; 1507 } 1508 1509 /* Allocate IV */ 1510 if (cc->iv_gen_ops && cc->iv_gen_ops->ctr) { 1511 ret = cc->iv_gen_ops->ctr(cc, ti, ivopts); 1512 if (ret < 0) { 1513 ti->error = "Error creating IV"; 1514 goto bad; 1515 } 1516 } 1517 1518 /* Initialize IV (set keys for ESSIV etc) */ 1519 if (cc->iv_gen_ops && cc->iv_gen_ops->init) { 1520 ret = cc->iv_gen_ops->init(cc); 1521 if (ret < 0) { 1522 ti->error = "Error initialising IV"; 1523 goto bad; 1524 } 1525 } 1526 1527 ret = 0; 1528 bad: 1529 kfree(cipher_api); 1530 return ret; 1531 1532 bad_mem: 1533 ti->error = "Cannot allocate cipher strings"; 1534 return -ENOMEM; 1535 } 1536 1537 /* 1538 * Construct an encryption mapping: 1539 * <cipher> <key> <iv_offset> <dev_path> <start> 1540 */ 1541 static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv) 1542 { 1543 struct crypt_config *cc; 1544 unsigned int key_size, opt_params; 1545 unsigned long long tmpll; 1546 int ret; 1547 struct dm_arg_set as; 1548 const char *opt_string; 1549 char dummy; 1550 1551 static struct dm_arg _args[] = { 1552 {0, 1, "Invalid number of feature args"}, 1553 }; 1554 1555 if (argc < 5) { 1556 ti->error = "Not enough arguments"; 1557 return -EINVAL; 1558 } 1559 1560 key_size = strlen(argv[1]) >> 1; 1561 1562 cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL); 1563 if (!cc) { 1564 ti->error = "Cannot allocate encryption context"; 1565 return -ENOMEM; 1566 } 1567 cc->key_size = key_size; 1568 1569 ti->private = cc; 1570 ret = crypt_ctr_cipher(ti, argv[0], argv[1]); 1571 if (ret < 0) 1572 goto bad; 1573 1574 ret = -ENOMEM; 1575 cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool); 1576 if (!cc->io_pool) { 1577 ti->error = "Cannot allocate crypt io mempool"; 1578 goto bad; 1579 } 1580 1581 cc->dmreq_start = sizeof(struct ablkcipher_request); 1582 cc->dmreq_start += crypto_ablkcipher_reqsize(any_tfm(cc)); 1583 cc->dmreq_start = ALIGN(cc->dmreq_start, crypto_tfm_ctx_alignment()); 1584 cc->dmreq_start += crypto_ablkcipher_alignmask(any_tfm(cc)) & 1585 ~(crypto_tfm_ctx_alignment() - 1); 1586 1587 cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start + 1588 sizeof(struct dm_crypt_request) + cc->iv_size); 1589 if (!cc->req_pool) { 1590 ti->error = "Cannot allocate crypt request mempool"; 1591 goto bad; 1592 } 1593 1594 cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0); 1595 if (!cc->page_pool) { 1596 ti->error = "Cannot allocate page mempool"; 1597 goto bad; 1598 } 1599 1600 cc->bs = bioset_create(MIN_IOS, 0); 1601 if (!cc->bs) { 1602 ti->error = "Cannot allocate crypt bioset"; 1603 goto bad; 1604 } 1605 1606 ret = -EINVAL; 1607 if (sscanf(argv[2], "%llu%c", &tmpll, &dummy) != 1) { 1608 ti->error = "Invalid iv_offset sector"; 1609 goto bad; 1610 } 1611 cc->iv_offset = tmpll; 1612 1613 if (dm_get_device(ti, argv[3], dm_table_get_mode(ti->table), &cc->dev)) { 1614 ti->error = "Device lookup failed"; 1615 goto bad; 1616 } 1617 1618 if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1) { 1619 ti->error = "Invalid device sector"; 1620 goto bad; 1621 } 1622 cc->start = tmpll; 1623 1624 argv += 5; 1625 argc -= 5; 1626 1627 /* Optional parameters */ 1628 if (argc) { 1629 as.argc = argc; 1630 as.argv = argv; 1631 1632 ret = dm_read_arg_group(_args, &as, &opt_params, &ti->error); 1633 if (ret) 1634 goto bad; 1635 1636 opt_string = dm_shift_arg(&as); 1637 1638 if (opt_params == 1 && opt_string && 1639 !strcasecmp(opt_string, "allow_discards")) 1640 ti->num_discard_bios = 1; 1641 else if (opt_params) { 1642 ret = -EINVAL; 1643 ti->error = "Invalid feature arguments"; 1644 goto bad; 1645 } 1646 } 1647 1648 ret = -ENOMEM; 1649 cc->io_queue = alloc_workqueue("kcryptd_io", 1650 WQ_NON_REENTRANT| 1651 WQ_MEM_RECLAIM, 1652 1); 1653 if (!cc->io_queue) { 1654 ti->error = "Couldn't create kcryptd io queue"; 1655 goto bad; 1656 } 1657 1658 cc->crypt_queue = alloc_workqueue("kcryptd", 1659 WQ_NON_REENTRANT| 1660 WQ_CPU_INTENSIVE| 1661 WQ_MEM_RECLAIM, 1662 1); 1663 if (!cc->crypt_queue) { 1664 ti->error = "Couldn't create kcryptd queue"; 1665 goto bad; 1666 } 1667 1668 ti->num_flush_bios = 1; 1669 ti->discard_zeroes_data_unsupported = true; 1670 1671 return 0; 1672 1673 bad: 1674 crypt_dtr(ti); 1675 return ret; 1676 } 1677 1678 static int crypt_map(struct dm_target *ti, struct bio *bio) 1679 { 1680 struct dm_crypt_io *io; 1681 struct crypt_config *cc = ti->private; 1682 1683 /* 1684 * If bio is REQ_FLUSH or REQ_DISCARD, just bypass crypt queues. 1685 * - for REQ_FLUSH device-mapper core ensures that no IO is in-flight 1686 * - for REQ_DISCARD caller must use flush if IO ordering matters 1687 */ 1688 if (unlikely(bio->bi_rw & (REQ_FLUSH | REQ_DISCARD))) { 1689 bio->bi_bdev = cc->dev->bdev; 1690 if (bio_sectors(bio)) 1691 bio->bi_sector = cc->start + dm_target_offset(ti, bio->bi_sector); 1692 return DM_MAPIO_REMAPPED; 1693 } 1694 1695 io = crypt_io_alloc(cc, bio, dm_target_offset(ti, bio->bi_sector)); 1696 1697 if (bio_data_dir(io->base_bio) == READ) { 1698 if (kcryptd_io_read(io, GFP_NOWAIT)) 1699 kcryptd_queue_io(io); 1700 } else 1701 kcryptd_queue_crypt(io); 1702 1703 return DM_MAPIO_SUBMITTED; 1704 } 1705 1706 static void crypt_status(struct dm_target *ti, status_type_t type, 1707 unsigned status_flags, char *result, unsigned maxlen) 1708 { 1709 struct crypt_config *cc = ti->private; 1710 unsigned i, sz = 0; 1711 1712 switch (type) { 1713 case STATUSTYPE_INFO: 1714 result[0] = '\0'; 1715 break; 1716 1717 case STATUSTYPE_TABLE: 1718 DMEMIT("%s ", cc->cipher_string); 1719 1720 if (cc->key_size > 0) 1721 for (i = 0; i < cc->key_size; i++) 1722 DMEMIT("%02x", cc->key[i]); 1723 else 1724 DMEMIT("-"); 1725 1726 DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset, 1727 cc->dev->name, (unsigned long long)cc->start); 1728 1729 if (ti->num_discard_bios) 1730 DMEMIT(" 1 allow_discards"); 1731 1732 break; 1733 } 1734 } 1735 1736 static void crypt_postsuspend(struct dm_target *ti) 1737 { 1738 struct crypt_config *cc = ti->private; 1739 1740 set_bit(DM_CRYPT_SUSPENDED, &cc->flags); 1741 } 1742 1743 static int crypt_preresume(struct dm_target *ti) 1744 { 1745 struct crypt_config *cc = ti->private; 1746 1747 if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) { 1748 DMERR("aborting resume - crypt key is not set."); 1749 return -EAGAIN; 1750 } 1751 1752 return 0; 1753 } 1754 1755 static void crypt_resume(struct dm_target *ti) 1756 { 1757 struct crypt_config *cc = ti->private; 1758 1759 clear_bit(DM_CRYPT_SUSPENDED, &cc->flags); 1760 } 1761 1762 /* Message interface 1763 * key set <key> 1764 * key wipe 1765 */ 1766 static int crypt_message(struct dm_target *ti, unsigned argc, char **argv) 1767 { 1768 struct crypt_config *cc = ti->private; 1769 int ret = -EINVAL; 1770 1771 if (argc < 2) 1772 goto error; 1773 1774 if (!strcasecmp(argv[0], "key")) { 1775 if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) { 1776 DMWARN("not suspended during key manipulation."); 1777 return -EINVAL; 1778 } 1779 if (argc == 3 && !strcasecmp(argv[1], "set")) { 1780 ret = crypt_set_key(cc, argv[2]); 1781 if (ret) 1782 return ret; 1783 if (cc->iv_gen_ops && cc->iv_gen_ops->init) 1784 ret = cc->iv_gen_ops->init(cc); 1785 return ret; 1786 } 1787 if (argc == 2 && !strcasecmp(argv[1], "wipe")) { 1788 if (cc->iv_gen_ops && cc->iv_gen_ops->wipe) { 1789 ret = cc->iv_gen_ops->wipe(cc); 1790 if (ret) 1791 return ret; 1792 } 1793 return crypt_wipe_key(cc); 1794 } 1795 } 1796 1797 error: 1798 DMWARN("unrecognised message received."); 1799 return -EINVAL; 1800 } 1801 1802 static int crypt_merge(struct dm_target *ti, struct bvec_merge_data *bvm, 1803 struct bio_vec *biovec, int max_size) 1804 { 1805 struct crypt_config *cc = ti->private; 1806 struct request_queue *q = bdev_get_queue(cc->dev->bdev); 1807 1808 if (!q->merge_bvec_fn) 1809 return max_size; 1810 1811 bvm->bi_bdev = cc->dev->bdev; 1812 bvm->bi_sector = cc->start + dm_target_offset(ti, bvm->bi_sector); 1813 1814 return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); 1815 } 1816 1817 static int crypt_iterate_devices(struct dm_target *ti, 1818 iterate_devices_callout_fn fn, void *data) 1819 { 1820 struct crypt_config *cc = ti->private; 1821 1822 return fn(ti, cc->dev, cc->start, ti->len, data); 1823 } 1824 1825 static struct target_type crypt_target = { 1826 .name = "crypt", 1827 .version = {1, 12, 1}, 1828 .module = THIS_MODULE, 1829 .ctr = crypt_ctr, 1830 .dtr = crypt_dtr, 1831 .map = crypt_map, 1832 .status = crypt_status, 1833 .postsuspend = crypt_postsuspend, 1834 .preresume = crypt_preresume, 1835 .resume = crypt_resume, 1836 .message = crypt_message, 1837 .merge = crypt_merge, 1838 .iterate_devices = crypt_iterate_devices, 1839 }; 1840 1841 static int __init dm_crypt_init(void) 1842 { 1843 int r; 1844 1845 _crypt_io_pool = KMEM_CACHE(dm_crypt_io, 0); 1846 if (!_crypt_io_pool) 1847 return -ENOMEM; 1848 1849 r = dm_register_target(&crypt_target); 1850 if (r < 0) { 1851 DMERR("register failed %d", r); 1852 kmem_cache_destroy(_crypt_io_pool); 1853 } 1854 1855 return r; 1856 } 1857 1858 static void __exit dm_crypt_exit(void) 1859 { 1860 dm_unregister_target(&crypt_target); 1861 kmem_cache_destroy(_crypt_io_pool); 1862 } 1863 1864 module_init(dm_crypt_init); 1865 module_exit(dm_crypt_exit); 1866 1867 MODULE_AUTHOR("Christophe Saout <christophe@saout.de>"); 1868 MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption"); 1869 MODULE_LICENSE("GPL"); 1870