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 <asm/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 #define MESG_STR(x) x, sizeof(x) 34 35 /* 36 * context holding the current state of a multi-part conversion 37 */ 38 struct convert_context { 39 struct completion restart; 40 struct bio *bio_in; 41 struct bio *bio_out; 42 unsigned int offset_in; 43 unsigned int offset_out; 44 unsigned int idx_in; 45 unsigned int idx_out; 46 sector_t sector; 47 atomic_t pending; 48 }; 49 50 /* 51 * per bio private data 52 */ 53 struct dm_crypt_io { 54 struct dm_target *target; 55 struct bio *base_bio; 56 struct work_struct work; 57 58 struct convert_context ctx; 59 60 atomic_t pending; 61 int error; 62 sector_t sector; 63 struct dm_crypt_io *base_io; 64 }; 65 66 struct dm_crypt_request { 67 struct convert_context *ctx; 68 struct scatterlist sg_in; 69 struct scatterlist sg_out; 70 sector_t iv_sector; 71 }; 72 73 struct crypt_config; 74 75 struct crypt_iv_operations { 76 int (*ctr)(struct crypt_config *cc, struct dm_target *ti, 77 const char *opts); 78 void (*dtr)(struct crypt_config *cc); 79 int (*init)(struct crypt_config *cc); 80 int (*wipe)(struct crypt_config *cc); 81 int (*generator)(struct crypt_config *cc, u8 *iv, 82 struct dm_crypt_request *dmreq); 83 int (*post)(struct crypt_config *cc, u8 *iv, 84 struct dm_crypt_request *dmreq); 85 }; 86 87 struct iv_essiv_private { 88 struct crypto_hash *hash_tfm; 89 u8 *salt; 90 }; 91 92 struct iv_benbi_private { 93 int shift; 94 }; 95 96 #define LMK_SEED_SIZE 64 /* hash + 0 */ 97 struct iv_lmk_private { 98 struct crypto_shash *hash_tfm; 99 u8 *seed; 100 }; 101 102 /* 103 * Crypt: maps a linear range of a block device 104 * and encrypts / decrypts at the same time. 105 */ 106 enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID }; 107 108 /* 109 * Duplicated per-CPU state for cipher. 110 */ 111 struct crypt_cpu { 112 struct ablkcipher_request *req; 113 /* ESSIV: struct crypto_cipher *essiv_tfm */ 114 void *iv_private; 115 struct crypto_ablkcipher *tfms[0]; 116 }; 117 118 /* 119 * The fields in here must be read only after initialization, 120 * changing state should be in crypt_cpu. 121 */ 122 struct crypt_config { 123 struct dm_dev *dev; 124 sector_t start; 125 126 /* 127 * pool for per bio private data, crypto requests and 128 * encryption requeusts/buffer pages 129 */ 130 mempool_t *io_pool; 131 mempool_t *req_pool; 132 mempool_t *page_pool; 133 struct bio_set *bs; 134 135 struct workqueue_struct *io_queue; 136 struct workqueue_struct *crypt_queue; 137 138 char *cipher; 139 char *cipher_string; 140 141 struct crypt_iv_operations *iv_gen_ops; 142 union { 143 struct iv_essiv_private essiv; 144 struct iv_benbi_private benbi; 145 struct iv_lmk_private lmk; 146 } iv_gen_private; 147 sector_t iv_offset; 148 unsigned int iv_size; 149 150 /* 151 * Duplicated per cpu state. Access through 152 * per_cpu_ptr() only. 153 */ 154 struct crypt_cpu __percpu *cpu; 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 #define MIN_BIO_PAGES 8 181 182 static struct kmem_cache *_crypt_io_pool; 183 184 static void clone_init(struct dm_crypt_io *, struct bio *); 185 static void kcryptd_queue_crypt(struct dm_crypt_io *io); 186 static u8 *iv_of_dmreq(struct crypt_config *cc, struct dm_crypt_request *dmreq); 187 188 static struct crypt_cpu *this_crypt_config(struct crypt_config *cc) 189 { 190 return this_cpu_ptr(cc->cpu); 191 } 192 193 /* 194 * Use this to access cipher attributes that are the same for each CPU. 195 */ 196 static struct crypto_ablkcipher *any_tfm(struct crypt_config *cc) 197 { 198 return __this_cpu_ptr(cc->cpu)->tfms[0]; 199 } 200 201 /* 202 * Different IV generation algorithms: 203 * 204 * plain: the initial vector is the 32-bit little-endian version of the sector 205 * number, padded with zeros if necessary. 206 * 207 * plain64: the initial vector is the 64-bit little-endian version of the sector 208 * number, padded with zeros if necessary. 209 * 210 * essiv: "encrypted sector|salt initial vector", the sector number is 211 * encrypted with the bulk cipher using a salt as key. The salt 212 * should be derived from the bulk cipher's key via hashing. 213 * 214 * benbi: the 64-bit "big-endian 'narrow block'-count", starting at 1 215 * (needed for LRW-32-AES and possible other narrow block modes) 216 * 217 * null: the initial vector is always zero. Provides compatibility with 218 * obsolete loop_fish2 devices. Do not use for new devices. 219 * 220 * lmk: Compatible implementation of the block chaining mode used 221 * by the Loop-AES block device encryption system 222 * designed by Jari Ruusu. See http://loop-aes.sourceforge.net/ 223 * It operates on full 512 byte sectors and uses CBC 224 * with an IV derived from the sector number, the data and 225 * optionally extra IV seed. 226 * This means that after decryption the first block 227 * of sector must be tweaked according to decrypted data. 228 * Loop-AES can use three encryption schemes: 229 * version 1: is plain aes-cbc mode 230 * version 2: uses 64 multikey scheme with lmk IV generator 231 * version 3: the same as version 2 with additional IV seed 232 * (it uses 65 keys, last key is used as IV seed) 233 * 234 * plumb: unimplemented, see: 235 * http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454 236 */ 237 238 static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv, 239 struct dm_crypt_request *dmreq) 240 { 241 memset(iv, 0, cc->iv_size); 242 *(u32 *)iv = cpu_to_le32(dmreq->iv_sector & 0xffffffff); 243 244 return 0; 245 } 246 247 static int crypt_iv_plain64_gen(struct crypt_config *cc, u8 *iv, 248 struct dm_crypt_request *dmreq) 249 { 250 memset(iv, 0, cc->iv_size); 251 *(u64 *)iv = cpu_to_le64(dmreq->iv_sector); 252 253 return 0; 254 } 255 256 /* Initialise ESSIV - compute salt but no local memory allocations */ 257 static int crypt_iv_essiv_init(struct crypt_config *cc) 258 { 259 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv; 260 struct hash_desc desc; 261 struct scatterlist sg; 262 struct crypto_cipher *essiv_tfm; 263 int err, cpu; 264 265 sg_init_one(&sg, cc->key, cc->key_size); 266 desc.tfm = essiv->hash_tfm; 267 desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; 268 269 err = crypto_hash_digest(&desc, &sg, cc->key_size, essiv->salt); 270 if (err) 271 return err; 272 273 for_each_possible_cpu(cpu) { 274 essiv_tfm = per_cpu_ptr(cc->cpu, cpu)->iv_private, 275 276 err = crypto_cipher_setkey(essiv_tfm, essiv->salt, 277 crypto_hash_digestsize(essiv->hash_tfm)); 278 if (err) 279 return err; 280 } 281 282 return 0; 283 } 284 285 /* Wipe salt and reset key derived from volume key */ 286 static int crypt_iv_essiv_wipe(struct crypt_config *cc) 287 { 288 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv; 289 unsigned salt_size = crypto_hash_digestsize(essiv->hash_tfm); 290 struct crypto_cipher *essiv_tfm; 291 int cpu, r, err = 0; 292 293 memset(essiv->salt, 0, salt_size); 294 295 for_each_possible_cpu(cpu) { 296 essiv_tfm = per_cpu_ptr(cc->cpu, cpu)->iv_private; 297 r = crypto_cipher_setkey(essiv_tfm, essiv->salt, salt_size); 298 if (r) 299 err = r; 300 } 301 302 return err; 303 } 304 305 /* Set up per cpu cipher state */ 306 static struct crypto_cipher *setup_essiv_cpu(struct crypt_config *cc, 307 struct dm_target *ti, 308 u8 *salt, unsigned saltsize) 309 { 310 struct crypto_cipher *essiv_tfm; 311 int err; 312 313 /* Setup the essiv_tfm with the given salt */ 314 essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC); 315 if (IS_ERR(essiv_tfm)) { 316 ti->error = "Error allocating crypto tfm for ESSIV"; 317 return essiv_tfm; 318 } 319 320 if (crypto_cipher_blocksize(essiv_tfm) != 321 crypto_ablkcipher_ivsize(any_tfm(cc))) { 322 ti->error = "Block size of ESSIV cipher does " 323 "not match IV size of block cipher"; 324 crypto_free_cipher(essiv_tfm); 325 return ERR_PTR(-EINVAL); 326 } 327 328 err = crypto_cipher_setkey(essiv_tfm, salt, saltsize); 329 if (err) { 330 ti->error = "Failed to set key for ESSIV cipher"; 331 crypto_free_cipher(essiv_tfm); 332 return ERR_PTR(err); 333 } 334 335 return essiv_tfm; 336 } 337 338 static void crypt_iv_essiv_dtr(struct crypt_config *cc) 339 { 340 int cpu; 341 struct crypt_cpu *cpu_cc; 342 struct crypto_cipher *essiv_tfm; 343 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv; 344 345 crypto_free_hash(essiv->hash_tfm); 346 essiv->hash_tfm = NULL; 347 348 kzfree(essiv->salt); 349 essiv->salt = NULL; 350 351 for_each_possible_cpu(cpu) { 352 cpu_cc = per_cpu_ptr(cc->cpu, cpu); 353 essiv_tfm = cpu_cc->iv_private; 354 355 if (essiv_tfm) 356 crypto_free_cipher(essiv_tfm); 357 358 cpu_cc->iv_private = NULL; 359 } 360 } 361 362 static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti, 363 const char *opts) 364 { 365 struct crypto_cipher *essiv_tfm = NULL; 366 struct crypto_hash *hash_tfm = NULL; 367 u8 *salt = NULL; 368 int err, cpu; 369 370 if (!opts) { 371 ti->error = "Digest algorithm missing for ESSIV mode"; 372 return -EINVAL; 373 } 374 375 /* Allocate hash algorithm */ 376 hash_tfm = crypto_alloc_hash(opts, 0, CRYPTO_ALG_ASYNC); 377 if (IS_ERR(hash_tfm)) { 378 ti->error = "Error initializing ESSIV hash"; 379 err = PTR_ERR(hash_tfm); 380 goto bad; 381 } 382 383 salt = kzalloc(crypto_hash_digestsize(hash_tfm), GFP_KERNEL); 384 if (!salt) { 385 ti->error = "Error kmallocing salt storage in ESSIV"; 386 err = -ENOMEM; 387 goto bad; 388 } 389 390 cc->iv_gen_private.essiv.salt = salt; 391 cc->iv_gen_private.essiv.hash_tfm = hash_tfm; 392 393 for_each_possible_cpu(cpu) { 394 essiv_tfm = setup_essiv_cpu(cc, ti, salt, 395 crypto_hash_digestsize(hash_tfm)); 396 if (IS_ERR(essiv_tfm)) { 397 crypt_iv_essiv_dtr(cc); 398 return PTR_ERR(essiv_tfm); 399 } 400 per_cpu_ptr(cc->cpu, cpu)->iv_private = essiv_tfm; 401 } 402 403 return 0; 404 405 bad: 406 if (hash_tfm && !IS_ERR(hash_tfm)) 407 crypto_free_hash(hash_tfm); 408 kfree(salt); 409 return err; 410 } 411 412 static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv, 413 struct dm_crypt_request *dmreq) 414 { 415 struct crypto_cipher *essiv_tfm = this_crypt_config(cc)->iv_private; 416 417 memset(iv, 0, cc->iv_size); 418 *(u64 *)iv = cpu_to_le64(dmreq->iv_sector); 419 crypto_cipher_encrypt_one(essiv_tfm, iv, iv); 420 421 return 0; 422 } 423 424 static int crypt_iv_benbi_ctr(struct crypt_config *cc, struct dm_target *ti, 425 const char *opts) 426 { 427 unsigned bs = crypto_ablkcipher_blocksize(any_tfm(cc)); 428 int log = ilog2(bs); 429 430 /* we need to calculate how far we must shift the sector count 431 * to get the cipher block count, we use this shift in _gen */ 432 433 if (1 << log != bs) { 434 ti->error = "cypher blocksize is not a power of 2"; 435 return -EINVAL; 436 } 437 438 if (log > 9) { 439 ti->error = "cypher blocksize is > 512"; 440 return -EINVAL; 441 } 442 443 cc->iv_gen_private.benbi.shift = 9 - log; 444 445 return 0; 446 } 447 448 static void crypt_iv_benbi_dtr(struct crypt_config *cc) 449 { 450 } 451 452 static int crypt_iv_benbi_gen(struct crypt_config *cc, u8 *iv, 453 struct dm_crypt_request *dmreq) 454 { 455 __be64 val; 456 457 memset(iv, 0, cc->iv_size - sizeof(u64)); /* rest is cleared below */ 458 459 val = cpu_to_be64(((u64)dmreq->iv_sector << cc->iv_gen_private.benbi.shift) + 1); 460 put_unaligned(val, (__be64 *)(iv + cc->iv_size - sizeof(u64))); 461 462 return 0; 463 } 464 465 static int crypt_iv_null_gen(struct crypt_config *cc, u8 *iv, 466 struct dm_crypt_request *dmreq) 467 { 468 memset(iv, 0, cc->iv_size); 469 470 return 0; 471 } 472 473 static void crypt_iv_lmk_dtr(struct crypt_config *cc) 474 { 475 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk; 476 477 if (lmk->hash_tfm && !IS_ERR(lmk->hash_tfm)) 478 crypto_free_shash(lmk->hash_tfm); 479 lmk->hash_tfm = NULL; 480 481 kzfree(lmk->seed); 482 lmk->seed = NULL; 483 } 484 485 static int crypt_iv_lmk_ctr(struct crypt_config *cc, struct dm_target *ti, 486 const char *opts) 487 { 488 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk; 489 490 lmk->hash_tfm = crypto_alloc_shash("md5", 0, 0); 491 if (IS_ERR(lmk->hash_tfm)) { 492 ti->error = "Error initializing LMK hash"; 493 return PTR_ERR(lmk->hash_tfm); 494 } 495 496 /* No seed in LMK version 2 */ 497 if (cc->key_parts == cc->tfms_count) { 498 lmk->seed = NULL; 499 return 0; 500 } 501 502 lmk->seed = kzalloc(LMK_SEED_SIZE, GFP_KERNEL); 503 if (!lmk->seed) { 504 crypt_iv_lmk_dtr(cc); 505 ti->error = "Error kmallocing seed storage in LMK"; 506 return -ENOMEM; 507 } 508 509 return 0; 510 } 511 512 static int crypt_iv_lmk_init(struct crypt_config *cc) 513 { 514 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk; 515 int subkey_size = cc->key_size / cc->key_parts; 516 517 /* LMK seed is on the position of LMK_KEYS + 1 key */ 518 if (lmk->seed) 519 memcpy(lmk->seed, cc->key + (cc->tfms_count * subkey_size), 520 crypto_shash_digestsize(lmk->hash_tfm)); 521 522 return 0; 523 } 524 525 static int crypt_iv_lmk_wipe(struct crypt_config *cc) 526 { 527 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk; 528 529 if (lmk->seed) 530 memset(lmk->seed, 0, LMK_SEED_SIZE); 531 532 return 0; 533 } 534 535 static int crypt_iv_lmk_one(struct crypt_config *cc, u8 *iv, 536 struct dm_crypt_request *dmreq, 537 u8 *data) 538 { 539 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk; 540 struct { 541 struct shash_desc desc; 542 char ctx[crypto_shash_descsize(lmk->hash_tfm)]; 543 } sdesc; 544 struct md5_state md5state; 545 u32 buf[4]; 546 int i, r; 547 548 sdesc.desc.tfm = lmk->hash_tfm; 549 sdesc.desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; 550 551 r = crypto_shash_init(&sdesc.desc); 552 if (r) 553 return r; 554 555 if (lmk->seed) { 556 r = crypto_shash_update(&sdesc.desc, lmk->seed, LMK_SEED_SIZE); 557 if (r) 558 return r; 559 } 560 561 /* Sector is always 512B, block size 16, add data of blocks 1-31 */ 562 r = crypto_shash_update(&sdesc.desc, data + 16, 16 * 31); 563 if (r) 564 return r; 565 566 /* Sector is cropped to 56 bits here */ 567 buf[0] = cpu_to_le32(dmreq->iv_sector & 0xFFFFFFFF); 568 buf[1] = cpu_to_le32((((u64)dmreq->iv_sector >> 32) & 0x00FFFFFF) | 0x80000000); 569 buf[2] = cpu_to_le32(4024); 570 buf[3] = 0; 571 r = crypto_shash_update(&sdesc.desc, (u8 *)buf, sizeof(buf)); 572 if (r) 573 return r; 574 575 /* No MD5 padding here */ 576 r = crypto_shash_export(&sdesc.desc, &md5state); 577 if (r) 578 return r; 579 580 for (i = 0; i < MD5_HASH_WORDS; i++) 581 __cpu_to_le32s(&md5state.hash[i]); 582 memcpy(iv, &md5state.hash, cc->iv_size); 583 584 return 0; 585 } 586 587 static int crypt_iv_lmk_gen(struct crypt_config *cc, u8 *iv, 588 struct dm_crypt_request *dmreq) 589 { 590 u8 *src; 591 int r = 0; 592 593 if (bio_data_dir(dmreq->ctx->bio_in) == WRITE) { 594 src = kmap_atomic(sg_page(&dmreq->sg_in), KM_USER0); 595 r = crypt_iv_lmk_one(cc, iv, dmreq, src + dmreq->sg_in.offset); 596 kunmap_atomic(src, KM_USER0); 597 } else 598 memset(iv, 0, cc->iv_size); 599 600 return r; 601 } 602 603 static int crypt_iv_lmk_post(struct crypt_config *cc, u8 *iv, 604 struct dm_crypt_request *dmreq) 605 { 606 u8 *dst; 607 int r; 608 609 if (bio_data_dir(dmreq->ctx->bio_in) == WRITE) 610 return 0; 611 612 dst = kmap_atomic(sg_page(&dmreq->sg_out), KM_USER0); 613 r = crypt_iv_lmk_one(cc, iv, dmreq, dst + dmreq->sg_out.offset); 614 615 /* Tweak the first block of plaintext sector */ 616 if (!r) 617 crypto_xor(dst + dmreq->sg_out.offset, iv, cc->iv_size); 618 619 kunmap_atomic(dst, KM_USER0); 620 return r; 621 } 622 623 static struct crypt_iv_operations crypt_iv_plain_ops = { 624 .generator = crypt_iv_plain_gen 625 }; 626 627 static struct crypt_iv_operations crypt_iv_plain64_ops = { 628 .generator = crypt_iv_plain64_gen 629 }; 630 631 static struct crypt_iv_operations crypt_iv_essiv_ops = { 632 .ctr = crypt_iv_essiv_ctr, 633 .dtr = crypt_iv_essiv_dtr, 634 .init = crypt_iv_essiv_init, 635 .wipe = crypt_iv_essiv_wipe, 636 .generator = crypt_iv_essiv_gen 637 }; 638 639 static struct crypt_iv_operations crypt_iv_benbi_ops = { 640 .ctr = crypt_iv_benbi_ctr, 641 .dtr = crypt_iv_benbi_dtr, 642 .generator = crypt_iv_benbi_gen 643 }; 644 645 static struct crypt_iv_operations crypt_iv_null_ops = { 646 .generator = crypt_iv_null_gen 647 }; 648 649 static struct crypt_iv_operations crypt_iv_lmk_ops = { 650 .ctr = crypt_iv_lmk_ctr, 651 .dtr = crypt_iv_lmk_dtr, 652 .init = crypt_iv_lmk_init, 653 .wipe = crypt_iv_lmk_wipe, 654 .generator = crypt_iv_lmk_gen, 655 .post = crypt_iv_lmk_post 656 }; 657 658 static void crypt_convert_init(struct crypt_config *cc, 659 struct convert_context *ctx, 660 struct bio *bio_out, struct bio *bio_in, 661 sector_t sector) 662 { 663 ctx->bio_in = bio_in; 664 ctx->bio_out = bio_out; 665 ctx->offset_in = 0; 666 ctx->offset_out = 0; 667 ctx->idx_in = bio_in ? bio_in->bi_idx : 0; 668 ctx->idx_out = bio_out ? bio_out->bi_idx : 0; 669 ctx->sector = sector + cc->iv_offset; 670 init_completion(&ctx->restart); 671 } 672 673 static struct dm_crypt_request *dmreq_of_req(struct crypt_config *cc, 674 struct ablkcipher_request *req) 675 { 676 return (struct dm_crypt_request *)((char *)req + cc->dmreq_start); 677 } 678 679 static struct ablkcipher_request *req_of_dmreq(struct crypt_config *cc, 680 struct dm_crypt_request *dmreq) 681 { 682 return (struct ablkcipher_request *)((char *)dmreq - cc->dmreq_start); 683 } 684 685 static u8 *iv_of_dmreq(struct crypt_config *cc, 686 struct dm_crypt_request *dmreq) 687 { 688 return (u8 *)ALIGN((unsigned long)(dmreq + 1), 689 crypto_ablkcipher_alignmask(any_tfm(cc)) + 1); 690 } 691 692 static int crypt_convert_block(struct crypt_config *cc, 693 struct convert_context *ctx, 694 struct ablkcipher_request *req) 695 { 696 struct bio_vec *bv_in = bio_iovec_idx(ctx->bio_in, ctx->idx_in); 697 struct bio_vec *bv_out = bio_iovec_idx(ctx->bio_out, ctx->idx_out); 698 struct dm_crypt_request *dmreq; 699 u8 *iv; 700 int r = 0; 701 702 dmreq = dmreq_of_req(cc, req); 703 iv = iv_of_dmreq(cc, dmreq); 704 705 dmreq->iv_sector = ctx->sector; 706 dmreq->ctx = ctx; 707 sg_init_table(&dmreq->sg_in, 1); 708 sg_set_page(&dmreq->sg_in, bv_in->bv_page, 1 << SECTOR_SHIFT, 709 bv_in->bv_offset + ctx->offset_in); 710 711 sg_init_table(&dmreq->sg_out, 1); 712 sg_set_page(&dmreq->sg_out, bv_out->bv_page, 1 << SECTOR_SHIFT, 713 bv_out->bv_offset + ctx->offset_out); 714 715 ctx->offset_in += 1 << SECTOR_SHIFT; 716 if (ctx->offset_in >= bv_in->bv_len) { 717 ctx->offset_in = 0; 718 ctx->idx_in++; 719 } 720 721 ctx->offset_out += 1 << SECTOR_SHIFT; 722 if (ctx->offset_out >= bv_out->bv_len) { 723 ctx->offset_out = 0; 724 ctx->idx_out++; 725 } 726 727 if (cc->iv_gen_ops) { 728 r = cc->iv_gen_ops->generator(cc, iv, dmreq); 729 if (r < 0) 730 return r; 731 } 732 733 ablkcipher_request_set_crypt(req, &dmreq->sg_in, &dmreq->sg_out, 734 1 << SECTOR_SHIFT, iv); 735 736 if (bio_data_dir(ctx->bio_in) == WRITE) 737 r = crypto_ablkcipher_encrypt(req); 738 else 739 r = crypto_ablkcipher_decrypt(req); 740 741 if (!r && cc->iv_gen_ops && cc->iv_gen_ops->post) 742 r = cc->iv_gen_ops->post(cc, iv, dmreq); 743 744 return r; 745 } 746 747 static void kcryptd_async_done(struct crypto_async_request *async_req, 748 int error); 749 750 static void crypt_alloc_req(struct crypt_config *cc, 751 struct convert_context *ctx) 752 { 753 struct crypt_cpu *this_cc = this_crypt_config(cc); 754 unsigned key_index = ctx->sector & (cc->tfms_count - 1); 755 756 if (!this_cc->req) 757 this_cc->req = mempool_alloc(cc->req_pool, GFP_NOIO); 758 759 ablkcipher_request_set_tfm(this_cc->req, this_cc->tfms[key_index]); 760 ablkcipher_request_set_callback(this_cc->req, 761 CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, 762 kcryptd_async_done, dmreq_of_req(cc, this_cc->req)); 763 } 764 765 /* 766 * Encrypt / decrypt data from one bio to another one (can be the same one) 767 */ 768 static int crypt_convert(struct crypt_config *cc, 769 struct convert_context *ctx) 770 { 771 struct crypt_cpu *this_cc = this_crypt_config(cc); 772 int r; 773 774 atomic_set(&ctx->pending, 1); 775 776 while(ctx->idx_in < ctx->bio_in->bi_vcnt && 777 ctx->idx_out < ctx->bio_out->bi_vcnt) { 778 779 crypt_alloc_req(cc, ctx); 780 781 atomic_inc(&ctx->pending); 782 783 r = crypt_convert_block(cc, ctx, this_cc->req); 784 785 switch (r) { 786 /* async */ 787 case -EBUSY: 788 wait_for_completion(&ctx->restart); 789 INIT_COMPLETION(ctx->restart); 790 /* fall through*/ 791 case -EINPROGRESS: 792 this_cc->req = NULL; 793 ctx->sector++; 794 continue; 795 796 /* sync */ 797 case 0: 798 atomic_dec(&ctx->pending); 799 ctx->sector++; 800 cond_resched(); 801 continue; 802 803 /* error */ 804 default: 805 atomic_dec(&ctx->pending); 806 return r; 807 } 808 } 809 810 return 0; 811 } 812 813 static void dm_crypt_bio_destructor(struct bio *bio) 814 { 815 struct dm_crypt_io *io = bio->bi_private; 816 struct crypt_config *cc = io->target->private; 817 818 bio_free(bio, cc->bs); 819 } 820 821 /* 822 * Generate a new unfragmented bio with the given size 823 * This should never violate the device limitations 824 * May return a smaller bio when running out of pages, indicated by 825 * *out_of_pages set to 1. 826 */ 827 static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size, 828 unsigned *out_of_pages) 829 { 830 struct crypt_config *cc = io->target->private; 831 struct bio *clone; 832 unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; 833 gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM; 834 unsigned i, len; 835 struct page *page; 836 837 clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs); 838 if (!clone) 839 return NULL; 840 841 clone_init(io, clone); 842 *out_of_pages = 0; 843 844 for (i = 0; i < nr_iovecs; i++) { 845 page = mempool_alloc(cc->page_pool, gfp_mask); 846 if (!page) { 847 *out_of_pages = 1; 848 break; 849 } 850 851 /* 852 * if additional pages cannot be allocated without waiting, 853 * return a partially allocated bio, the caller will then try 854 * to allocate additional bios while submitting this partial bio 855 */ 856 if (i == (MIN_BIO_PAGES - 1)) 857 gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT; 858 859 len = (size > PAGE_SIZE) ? PAGE_SIZE : size; 860 861 if (!bio_add_page(clone, page, len, 0)) { 862 mempool_free(page, cc->page_pool); 863 break; 864 } 865 866 size -= len; 867 } 868 869 if (!clone->bi_size) { 870 bio_put(clone); 871 return NULL; 872 } 873 874 return clone; 875 } 876 877 static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone) 878 { 879 unsigned int i; 880 struct bio_vec *bv; 881 882 for (i = 0; i < clone->bi_vcnt; i++) { 883 bv = bio_iovec_idx(clone, i); 884 BUG_ON(!bv->bv_page); 885 mempool_free(bv->bv_page, cc->page_pool); 886 bv->bv_page = NULL; 887 } 888 } 889 890 static struct dm_crypt_io *crypt_io_alloc(struct dm_target *ti, 891 struct bio *bio, sector_t sector) 892 { 893 struct crypt_config *cc = ti->private; 894 struct dm_crypt_io *io; 895 896 io = mempool_alloc(cc->io_pool, GFP_NOIO); 897 io->target = ti; 898 io->base_bio = bio; 899 io->sector = sector; 900 io->error = 0; 901 io->base_io = NULL; 902 atomic_set(&io->pending, 0); 903 904 return io; 905 } 906 907 static void crypt_inc_pending(struct dm_crypt_io *io) 908 { 909 atomic_inc(&io->pending); 910 } 911 912 /* 913 * One of the bios was finished. Check for completion of 914 * the whole request and correctly clean up the buffer. 915 * If base_io is set, wait for the last fragment to complete. 916 */ 917 static void crypt_dec_pending(struct dm_crypt_io *io) 918 { 919 struct crypt_config *cc = io->target->private; 920 struct bio *base_bio = io->base_bio; 921 struct dm_crypt_io *base_io = io->base_io; 922 int error = io->error; 923 924 if (!atomic_dec_and_test(&io->pending)) 925 return; 926 927 mempool_free(io, cc->io_pool); 928 929 if (likely(!base_io)) 930 bio_endio(base_bio, error); 931 else { 932 if (error && !base_io->error) 933 base_io->error = error; 934 crypt_dec_pending(base_io); 935 } 936 } 937 938 /* 939 * kcryptd/kcryptd_io: 940 * 941 * Needed because it would be very unwise to do decryption in an 942 * interrupt context. 943 * 944 * kcryptd performs the actual encryption or decryption. 945 * 946 * kcryptd_io performs the IO submission. 947 * 948 * They must be separated as otherwise the final stages could be 949 * starved by new requests which can block in the first stages due 950 * to memory allocation. 951 * 952 * The work is done per CPU global for all dm-crypt instances. 953 * They should not depend on each other and do not block. 954 */ 955 static void crypt_endio(struct bio *clone, int error) 956 { 957 struct dm_crypt_io *io = clone->bi_private; 958 struct crypt_config *cc = io->target->private; 959 unsigned rw = bio_data_dir(clone); 960 961 if (unlikely(!bio_flagged(clone, BIO_UPTODATE) && !error)) 962 error = -EIO; 963 964 /* 965 * free the processed pages 966 */ 967 if (rw == WRITE) 968 crypt_free_buffer_pages(cc, clone); 969 970 bio_put(clone); 971 972 if (rw == READ && !error) { 973 kcryptd_queue_crypt(io); 974 return; 975 } 976 977 if (unlikely(error)) 978 io->error = error; 979 980 crypt_dec_pending(io); 981 } 982 983 static void clone_init(struct dm_crypt_io *io, struct bio *clone) 984 { 985 struct crypt_config *cc = io->target->private; 986 987 clone->bi_private = io; 988 clone->bi_end_io = crypt_endio; 989 clone->bi_bdev = cc->dev->bdev; 990 clone->bi_rw = io->base_bio->bi_rw; 991 clone->bi_destructor = dm_crypt_bio_destructor; 992 } 993 994 static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp) 995 { 996 struct crypt_config *cc = io->target->private; 997 struct bio *base_bio = io->base_bio; 998 struct bio *clone; 999 1000 /* 1001 * The block layer might modify the bvec array, so always 1002 * copy the required bvecs because we need the original 1003 * one in order to decrypt the whole bio data *afterwards*. 1004 */ 1005 clone = bio_alloc_bioset(gfp, bio_segments(base_bio), cc->bs); 1006 if (!clone) 1007 return 1; 1008 1009 crypt_inc_pending(io); 1010 1011 clone_init(io, clone); 1012 clone->bi_idx = 0; 1013 clone->bi_vcnt = bio_segments(base_bio); 1014 clone->bi_size = base_bio->bi_size; 1015 clone->bi_sector = cc->start + io->sector; 1016 memcpy(clone->bi_io_vec, bio_iovec(base_bio), 1017 sizeof(struct bio_vec) * clone->bi_vcnt); 1018 1019 generic_make_request(clone); 1020 return 0; 1021 } 1022 1023 static void kcryptd_io_write(struct dm_crypt_io *io) 1024 { 1025 struct bio *clone = io->ctx.bio_out; 1026 generic_make_request(clone); 1027 } 1028 1029 static void kcryptd_io(struct work_struct *work) 1030 { 1031 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work); 1032 1033 if (bio_data_dir(io->base_bio) == READ) { 1034 crypt_inc_pending(io); 1035 if (kcryptd_io_read(io, GFP_NOIO)) 1036 io->error = -ENOMEM; 1037 crypt_dec_pending(io); 1038 } else 1039 kcryptd_io_write(io); 1040 } 1041 1042 static void kcryptd_queue_io(struct dm_crypt_io *io) 1043 { 1044 struct crypt_config *cc = io->target->private; 1045 1046 INIT_WORK(&io->work, kcryptd_io); 1047 queue_work(cc->io_queue, &io->work); 1048 } 1049 1050 static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io, 1051 int error, int async) 1052 { 1053 struct bio *clone = io->ctx.bio_out; 1054 struct crypt_config *cc = io->target->private; 1055 1056 if (unlikely(error < 0)) { 1057 crypt_free_buffer_pages(cc, clone); 1058 bio_put(clone); 1059 io->error = -EIO; 1060 crypt_dec_pending(io); 1061 return; 1062 } 1063 1064 /* crypt_convert should have filled the clone bio */ 1065 BUG_ON(io->ctx.idx_out < clone->bi_vcnt); 1066 1067 clone->bi_sector = cc->start + io->sector; 1068 1069 if (async) 1070 kcryptd_queue_io(io); 1071 else 1072 generic_make_request(clone); 1073 } 1074 1075 static void kcryptd_crypt_write_convert(struct dm_crypt_io *io) 1076 { 1077 struct crypt_config *cc = io->target->private; 1078 struct bio *clone; 1079 struct dm_crypt_io *new_io; 1080 int crypt_finished; 1081 unsigned out_of_pages = 0; 1082 unsigned remaining = io->base_bio->bi_size; 1083 sector_t sector = io->sector; 1084 int r; 1085 1086 /* 1087 * Prevent io from disappearing until this function completes. 1088 */ 1089 crypt_inc_pending(io); 1090 crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, sector); 1091 1092 /* 1093 * The allocated buffers can be smaller than the whole bio, 1094 * so repeat the whole process until all the data can be handled. 1095 */ 1096 while (remaining) { 1097 clone = crypt_alloc_buffer(io, remaining, &out_of_pages); 1098 if (unlikely(!clone)) { 1099 io->error = -ENOMEM; 1100 break; 1101 } 1102 1103 io->ctx.bio_out = clone; 1104 io->ctx.idx_out = 0; 1105 1106 remaining -= clone->bi_size; 1107 sector += bio_sectors(clone); 1108 1109 crypt_inc_pending(io); 1110 r = crypt_convert(cc, &io->ctx); 1111 crypt_finished = atomic_dec_and_test(&io->ctx.pending); 1112 1113 /* Encryption was already finished, submit io now */ 1114 if (crypt_finished) { 1115 kcryptd_crypt_write_io_submit(io, r, 0); 1116 1117 /* 1118 * If there was an error, do not try next fragments. 1119 * For async, error is processed in async handler. 1120 */ 1121 if (unlikely(r < 0)) 1122 break; 1123 1124 io->sector = sector; 1125 } 1126 1127 /* 1128 * Out of memory -> run queues 1129 * But don't wait if split was due to the io size restriction 1130 */ 1131 if (unlikely(out_of_pages)) 1132 congestion_wait(BLK_RW_ASYNC, HZ/100); 1133 1134 /* 1135 * With async crypto it is unsafe to share the crypto context 1136 * between fragments, so switch to a new dm_crypt_io structure. 1137 */ 1138 if (unlikely(!crypt_finished && remaining)) { 1139 new_io = crypt_io_alloc(io->target, io->base_bio, 1140 sector); 1141 crypt_inc_pending(new_io); 1142 crypt_convert_init(cc, &new_io->ctx, NULL, 1143 io->base_bio, sector); 1144 new_io->ctx.idx_in = io->ctx.idx_in; 1145 new_io->ctx.offset_in = io->ctx.offset_in; 1146 1147 /* 1148 * Fragments after the first use the base_io 1149 * pending count. 1150 */ 1151 if (!io->base_io) 1152 new_io->base_io = io; 1153 else { 1154 new_io->base_io = io->base_io; 1155 crypt_inc_pending(io->base_io); 1156 crypt_dec_pending(io); 1157 } 1158 1159 io = new_io; 1160 } 1161 } 1162 1163 crypt_dec_pending(io); 1164 } 1165 1166 static void kcryptd_crypt_read_done(struct dm_crypt_io *io, int error) 1167 { 1168 if (unlikely(error < 0)) 1169 io->error = -EIO; 1170 1171 crypt_dec_pending(io); 1172 } 1173 1174 static void kcryptd_crypt_read_convert(struct dm_crypt_io *io) 1175 { 1176 struct crypt_config *cc = io->target->private; 1177 int r = 0; 1178 1179 crypt_inc_pending(io); 1180 1181 crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio, 1182 io->sector); 1183 1184 r = crypt_convert(cc, &io->ctx); 1185 1186 if (atomic_dec_and_test(&io->ctx.pending)) 1187 kcryptd_crypt_read_done(io, r); 1188 1189 crypt_dec_pending(io); 1190 } 1191 1192 static void kcryptd_async_done(struct crypto_async_request *async_req, 1193 int error) 1194 { 1195 struct dm_crypt_request *dmreq = async_req->data; 1196 struct convert_context *ctx = dmreq->ctx; 1197 struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx); 1198 struct crypt_config *cc = io->target->private; 1199 1200 if (error == -EINPROGRESS) { 1201 complete(&ctx->restart); 1202 return; 1203 } 1204 1205 if (!error && cc->iv_gen_ops && cc->iv_gen_ops->post) 1206 error = cc->iv_gen_ops->post(cc, iv_of_dmreq(cc, dmreq), dmreq); 1207 1208 mempool_free(req_of_dmreq(cc, dmreq), cc->req_pool); 1209 1210 if (!atomic_dec_and_test(&ctx->pending)) 1211 return; 1212 1213 if (bio_data_dir(io->base_bio) == READ) 1214 kcryptd_crypt_read_done(io, error); 1215 else 1216 kcryptd_crypt_write_io_submit(io, error, 1); 1217 } 1218 1219 static void kcryptd_crypt(struct work_struct *work) 1220 { 1221 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work); 1222 1223 if (bio_data_dir(io->base_bio) == READ) 1224 kcryptd_crypt_read_convert(io); 1225 else 1226 kcryptd_crypt_write_convert(io); 1227 } 1228 1229 static void kcryptd_queue_crypt(struct dm_crypt_io *io) 1230 { 1231 struct crypt_config *cc = io->target->private; 1232 1233 INIT_WORK(&io->work, kcryptd_crypt); 1234 queue_work(cc->crypt_queue, &io->work); 1235 } 1236 1237 /* 1238 * Decode key from its hex representation 1239 */ 1240 static int crypt_decode_key(u8 *key, char *hex, unsigned int size) 1241 { 1242 char buffer[3]; 1243 char *endp; 1244 unsigned int i; 1245 1246 buffer[2] = '\0'; 1247 1248 for (i = 0; i < size; i++) { 1249 buffer[0] = *hex++; 1250 buffer[1] = *hex++; 1251 1252 key[i] = (u8)simple_strtoul(buffer, &endp, 16); 1253 1254 if (endp != &buffer[2]) 1255 return -EINVAL; 1256 } 1257 1258 if (*hex != '\0') 1259 return -EINVAL; 1260 1261 return 0; 1262 } 1263 1264 /* 1265 * Encode key into its hex representation 1266 */ 1267 static void crypt_encode_key(char *hex, u8 *key, unsigned int size) 1268 { 1269 unsigned int i; 1270 1271 for (i = 0; i < size; i++) { 1272 sprintf(hex, "%02x", *key); 1273 hex += 2; 1274 key++; 1275 } 1276 } 1277 1278 static void crypt_free_tfms(struct crypt_config *cc, int cpu) 1279 { 1280 struct crypt_cpu *cpu_cc = per_cpu_ptr(cc->cpu, cpu); 1281 unsigned i; 1282 1283 for (i = 0; i < cc->tfms_count; i++) 1284 if (cpu_cc->tfms[i] && !IS_ERR(cpu_cc->tfms[i])) { 1285 crypto_free_ablkcipher(cpu_cc->tfms[i]); 1286 cpu_cc->tfms[i] = NULL; 1287 } 1288 } 1289 1290 static int crypt_alloc_tfms(struct crypt_config *cc, int cpu, char *ciphermode) 1291 { 1292 struct crypt_cpu *cpu_cc = per_cpu_ptr(cc->cpu, cpu); 1293 unsigned i; 1294 int err; 1295 1296 for (i = 0; i < cc->tfms_count; i++) { 1297 cpu_cc->tfms[i] = crypto_alloc_ablkcipher(ciphermode, 0, 0); 1298 if (IS_ERR(cpu_cc->tfms[i])) { 1299 err = PTR_ERR(cpu_cc->tfms[i]); 1300 crypt_free_tfms(cc, cpu); 1301 return err; 1302 } 1303 } 1304 1305 return 0; 1306 } 1307 1308 static int crypt_setkey_allcpus(struct crypt_config *cc) 1309 { 1310 unsigned subkey_size = cc->key_size >> ilog2(cc->tfms_count); 1311 int cpu, err = 0, i, r; 1312 1313 for_each_possible_cpu(cpu) { 1314 for (i = 0; i < cc->tfms_count; i++) { 1315 r = crypto_ablkcipher_setkey(per_cpu_ptr(cc->cpu, cpu)->tfms[i], 1316 cc->key + (i * subkey_size), subkey_size); 1317 if (r) 1318 err = r; 1319 } 1320 } 1321 1322 return err; 1323 } 1324 1325 static int crypt_set_key(struct crypt_config *cc, char *key) 1326 { 1327 int r = -EINVAL; 1328 int key_string_len = strlen(key); 1329 1330 /* The key size may not be changed. */ 1331 if (cc->key_size != (key_string_len >> 1)) 1332 goto out; 1333 1334 /* Hyphen (which gives a key_size of zero) means there is no key. */ 1335 if (!cc->key_size && strcmp(key, "-")) 1336 goto out; 1337 1338 if (cc->key_size && crypt_decode_key(cc->key, key, cc->key_size) < 0) 1339 goto out; 1340 1341 set_bit(DM_CRYPT_KEY_VALID, &cc->flags); 1342 1343 r = crypt_setkey_allcpus(cc); 1344 1345 out: 1346 /* Hex key string not needed after here, so wipe it. */ 1347 memset(key, '0', key_string_len); 1348 1349 return r; 1350 } 1351 1352 static int crypt_wipe_key(struct crypt_config *cc) 1353 { 1354 clear_bit(DM_CRYPT_KEY_VALID, &cc->flags); 1355 memset(&cc->key, 0, cc->key_size * sizeof(u8)); 1356 1357 return crypt_setkey_allcpus(cc); 1358 } 1359 1360 static void crypt_dtr(struct dm_target *ti) 1361 { 1362 struct crypt_config *cc = ti->private; 1363 struct crypt_cpu *cpu_cc; 1364 int cpu; 1365 1366 ti->private = NULL; 1367 1368 if (!cc) 1369 return; 1370 1371 if (cc->io_queue) 1372 destroy_workqueue(cc->io_queue); 1373 if (cc->crypt_queue) 1374 destroy_workqueue(cc->crypt_queue); 1375 1376 if (cc->cpu) 1377 for_each_possible_cpu(cpu) { 1378 cpu_cc = per_cpu_ptr(cc->cpu, cpu); 1379 if (cpu_cc->req) 1380 mempool_free(cpu_cc->req, cc->req_pool); 1381 crypt_free_tfms(cc, cpu); 1382 } 1383 1384 if (cc->bs) 1385 bioset_free(cc->bs); 1386 1387 if (cc->page_pool) 1388 mempool_destroy(cc->page_pool); 1389 if (cc->req_pool) 1390 mempool_destroy(cc->req_pool); 1391 if (cc->io_pool) 1392 mempool_destroy(cc->io_pool); 1393 1394 if (cc->iv_gen_ops && cc->iv_gen_ops->dtr) 1395 cc->iv_gen_ops->dtr(cc); 1396 1397 if (cc->dev) 1398 dm_put_device(ti, cc->dev); 1399 1400 if (cc->cpu) 1401 free_percpu(cc->cpu); 1402 1403 kzfree(cc->cipher); 1404 kzfree(cc->cipher_string); 1405 1406 /* Must zero key material before freeing */ 1407 kzfree(cc); 1408 } 1409 1410 static int crypt_ctr_cipher(struct dm_target *ti, 1411 char *cipher_in, char *key) 1412 { 1413 struct crypt_config *cc = ti->private; 1414 char *tmp, *cipher, *chainmode, *ivmode, *ivopts, *keycount; 1415 char *cipher_api = NULL; 1416 int cpu, ret = -EINVAL; 1417 1418 /* Convert to crypto api definition? */ 1419 if (strchr(cipher_in, '(')) { 1420 ti->error = "Bad cipher specification"; 1421 return -EINVAL; 1422 } 1423 1424 cc->cipher_string = kstrdup(cipher_in, GFP_KERNEL); 1425 if (!cc->cipher_string) 1426 goto bad_mem; 1427 1428 /* 1429 * Legacy dm-crypt cipher specification 1430 * cipher[:keycount]-mode-iv:ivopts 1431 */ 1432 tmp = cipher_in; 1433 keycount = strsep(&tmp, "-"); 1434 cipher = strsep(&keycount, ":"); 1435 1436 if (!keycount) 1437 cc->tfms_count = 1; 1438 else if (sscanf(keycount, "%u", &cc->tfms_count) != 1 || 1439 !is_power_of_2(cc->tfms_count)) { 1440 ti->error = "Bad cipher key count specification"; 1441 return -EINVAL; 1442 } 1443 cc->key_parts = cc->tfms_count; 1444 1445 cc->cipher = kstrdup(cipher, GFP_KERNEL); 1446 if (!cc->cipher) 1447 goto bad_mem; 1448 1449 chainmode = strsep(&tmp, "-"); 1450 ivopts = strsep(&tmp, "-"); 1451 ivmode = strsep(&ivopts, ":"); 1452 1453 if (tmp) 1454 DMWARN("Ignoring unexpected additional cipher options"); 1455 1456 cc->cpu = __alloc_percpu(sizeof(*(cc->cpu)) + 1457 cc->tfms_count * sizeof(*(cc->cpu->tfms)), 1458 __alignof__(struct crypt_cpu)); 1459 if (!cc->cpu) { 1460 ti->error = "Cannot allocate per cpu state"; 1461 goto bad_mem; 1462 } 1463 1464 /* 1465 * For compatibility with the original dm-crypt mapping format, if 1466 * only the cipher name is supplied, use cbc-plain. 1467 */ 1468 if (!chainmode || (!strcmp(chainmode, "plain") && !ivmode)) { 1469 chainmode = "cbc"; 1470 ivmode = "plain"; 1471 } 1472 1473 if (strcmp(chainmode, "ecb") && !ivmode) { 1474 ti->error = "IV mechanism required"; 1475 return -EINVAL; 1476 } 1477 1478 cipher_api = kmalloc(CRYPTO_MAX_ALG_NAME, GFP_KERNEL); 1479 if (!cipher_api) 1480 goto bad_mem; 1481 1482 ret = snprintf(cipher_api, CRYPTO_MAX_ALG_NAME, 1483 "%s(%s)", chainmode, cipher); 1484 if (ret < 0) { 1485 kfree(cipher_api); 1486 goto bad_mem; 1487 } 1488 1489 /* Allocate cipher */ 1490 for_each_possible_cpu(cpu) { 1491 ret = crypt_alloc_tfms(cc, cpu, cipher_api); 1492 if (ret < 0) { 1493 ti->error = "Error allocating crypto tfm"; 1494 goto bad; 1495 } 1496 } 1497 1498 /* Initialize and set key */ 1499 ret = crypt_set_key(cc, key); 1500 if (ret < 0) { 1501 ti->error = "Error decoding and setting key"; 1502 goto bad; 1503 } 1504 1505 /* Initialize IV */ 1506 cc->iv_size = crypto_ablkcipher_ivsize(any_tfm(cc)); 1507 if (cc->iv_size) 1508 /* at least a 64 bit sector number should fit in our buffer */ 1509 cc->iv_size = max(cc->iv_size, 1510 (unsigned int)(sizeof(u64) / sizeof(u8))); 1511 else if (ivmode) { 1512 DMWARN("Selected cipher does not support IVs"); 1513 ivmode = NULL; 1514 } 1515 1516 /* Choose ivmode, see comments at iv code. */ 1517 if (ivmode == NULL) 1518 cc->iv_gen_ops = NULL; 1519 else if (strcmp(ivmode, "plain") == 0) 1520 cc->iv_gen_ops = &crypt_iv_plain_ops; 1521 else if (strcmp(ivmode, "plain64") == 0) 1522 cc->iv_gen_ops = &crypt_iv_plain64_ops; 1523 else if (strcmp(ivmode, "essiv") == 0) 1524 cc->iv_gen_ops = &crypt_iv_essiv_ops; 1525 else if (strcmp(ivmode, "benbi") == 0) 1526 cc->iv_gen_ops = &crypt_iv_benbi_ops; 1527 else if (strcmp(ivmode, "null") == 0) 1528 cc->iv_gen_ops = &crypt_iv_null_ops; 1529 else if (strcmp(ivmode, "lmk") == 0) { 1530 cc->iv_gen_ops = &crypt_iv_lmk_ops; 1531 /* Version 2 and 3 is recognised according 1532 * to length of provided multi-key string. 1533 * If present (version 3), last key is used as IV seed. 1534 */ 1535 if (cc->key_size % cc->key_parts) 1536 cc->key_parts++; 1537 } else { 1538 ret = -EINVAL; 1539 ti->error = "Invalid IV mode"; 1540 goto bad; 1541 } 1542 1543 /* Allocate IV */ 1544 if (cc->iv_gen_ops && cc->iv_gen_ops->ctr) { 1545 ret = cc->iv_gen_ops->ctr(cc, ti, ivopts); 1546 if (ret < 0) { 1547 ti->error = "Error creating IV"; 1548 goto bad; 1549 } 1550 } 1551 1552 /* Initialize IV (set keys for ESSIV etc) */ 1553 if (cc->iv_gen_ops && cc->iv_gen_ops->init) { 1554 ret = cc->iv_gen_ops->init(cc); 1555 if (ret < 0) { 1556 ti->error = "Error initialising IV"; 1557 goto bad; 1558 } 1559 } 1560 1561 ret = 0; 1562 bad: 1563 kfree(cipher_api); 1564 return ret; 1565 1566 bad_mem: 1567 ti->error = "Cannot allocate cipher strings"; 1568 return -ENOMEM; 1569 } 1570 1571 /* 1572 * Construct an encryption mapping: 1573 * <cipher> <key> <iv_offset> <dev_path> <start> 1574 */ 1575 static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv) 1576 { 1577 struct crypt_config *cc; 1578 unsigned int key_size; 1579 unsigned long long tmpll; 1580 int ret; 1581 1582 if (argc != 5) { 1583 ti->error = "Not enough arguments"; 1584 return -EINVAL; 1585 } 1586 1587 key_size = strlen(argv[1]) >> 1; 1588 1589 cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL); 1590 if (!cc) { 1591 ti->error = "Cannot allocate encryption context"; 1592 return -ENOMEM; 1593 } 1594 cc->key_size = key_size; 1595 1596 ti->private = cc; 1597 ret = crypt_ctr_cipher(ti, argv[0], argv[1]); 1598 if (ret < 0) 1599 goto bad; 1600 1601 ret = -ENOMEM; 1602 cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool); 1603 if (!cc->io_pool) { 1604 ti->error = "Cannot allocate crypt io mempool"; 1605 goto bad; 1606 } 1607 1608 cc->dmreq_start = sizeof(struct ablkcipher_request); 1609 cc->dmreq_start += crypto_ablkcipher_reqsize(any_tfm(cc)); 1610 cc->dmreq_start = ALIGN(cc->dmreq_start, crypto_tfm_ctx_alignment()); 1611 cc->dmreq_start += crypto_ablkcipher_alignmask(any_tfm(cc)) & 1612 ~(crypto_tfm_ctx_alignment() - 1); 1613 1614 cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start + 1615 sizeof(struct dm_crypt_request) + cc->iv_size); 1616 if (!cc->req_pool) { 1617 ti->error = "Cannot allocate crypt request mempool"; 1618 goto bad; 1619 } 1620 1621 cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0); 1622 if (!cc->page_pool) { 1623 ti->error = "Cannot allocate page mempool"; 1624 goto bad; 1625 } 1626 1627 cc->bs = bioset_create(MIN_IOS, 0); 1628 if (!cc->bs) { 1629 ti->error = "Cannot allocate crypt bioset"; 1630 goto bad; 1631 } 1632 1633 ret = -EINVAL; 1634 if (sscanf(argv[2], "%llu", &tmpll) != 1) { 1635 ti->error = "Invalid iv_offset sector"; 1636 goto bad; 1637 } 1638 cc->iv_offset = tmpll; 1639 1640 if (dm_get_device(ti, argv[3], dm_table_get_mode(ti->table), &cc->dev)) { 1641 ti->error = "Device lookup failed"; 1642 goto bad; 1643 } 1644 1645 if (sscanf(argv[4], "%llu", &tmpll) != 1) { 1646 ti->error = "Invalid device sector"; 1647 goto bad; 1648 } 1649 cc->start = tmpll; 1650 1651 ret = -ENOMEM; 1652 cc->io_queue = alloc_workqueue("kcryptd_io", 1653 WQ_NON_REENTRANT| 1654 WQ_MEM_RECLAIM, 1655 1); 1656 if (!cc->io_queue) { 1657 ti->error = "Couldn't create kcryptd io queue"; 1658 goto bad; 1659 } 1660 1661 cc->crypt_queue = alloc_workqueue("kcryptd", 1662 WQ_NON_REENTRANT| 1663 WQ_CPU_INTENSIVE| 1664 WQ_MEM_RECLAIM, 1665 1); 1666 if (!cc->crypt_queue) { 1667 ti->error = "Couldn't create kcryptd queue"; 1668 goto bad; 1669 } 1670 1671 ti->num_flush_requests = 1; 1672 return 0; 1673 1674 bad: 1675 crypt_dtr(ti); 1676 return ret; 1677 } 1678 1679 static int crypt_map(struct dm_target *ti, struct bio *bio, 1680 union map_info *map_context) 1681 { 1682 struct dm_crypt_io *io; 1683 struct crypt_config *cc; 1684 1685 if (bio->bi_rw & REQ_FLUSH) { 1686 cc = ti->private; 1687 bio->bi_bdev = cc->dev->bdev; 1688 return DM_MAPIO_REMAPPED; 1689 } 1690 1691 io = crypt_io_alloc(ti, bio, dm_target_offset(ti, bio->bi_sector)); 1692 1693 if (bio_data_dir(io->base_bio) == READ) { 1694 if (kcryptd_io_read(io, GFP_NOWAIT)) 1695 kcryptd_queue_io(io); 1696 } else 1697 kcryptd_queue_crypt(io); 1698 1699 return DM_MAPIO_SUBMITTED; 1700 } 1701 1702 static int crypt_status(struct dm_target *ti, status_type_t type, 1703 char *result, unsigned int maxlen) 1704 { 1705 struct crypt_config *cc = ti->private; 1706 unsigned int sz = 0; 1707 1708 switch (type) { 1709 case STATUSTYPE_INFO: 1710 result[0] = '\0'; 1711 break; 1712 1713 case STATUSTYPE_TABLE: 1714 DMEMIT("%s ", cc->cipher_string); 1715 1716 if (cc->key_size > 0) { 1717 if ((maxlen - sz) < ((cc->key_size << 1) + 1)) 1718 return -ENOMEM; 1719 1720 crypt_encode_key(result + sz, cc->key, cc->key_size); 1721 sz += cc->key_size << 1; 1722 } else { 1723 if (sz >= maxlen) 1724 return -ENOMEM; 1725 result[sz++] = '-'; 1726 } 1727 1728 DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset, 1729 cc->dev->name, (unsigned long long)cc->start); 1730 break; 1731 } 1732 return 0; 1733 } 1734 1735 static void crypt_postsuspend(struct dm_target *ti) 1736 { 1737 struct crypt_config *cc = ti->private; 1738 1739 set_bit(DM_CRYPT_SUSPENDED, &cc->flags); 1740 } 1741 1742 static int crypt_preresume(struct dm_target *ti) 1743 { 1744 struct crypt_config *cc = ti->private; 1745 1746 if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) { 1747 DMERR("aborting resume - crypt key is not set."); 1748 return -EAGAIN; 1749 } 1750 1751 return 0; 1752 } 1753 1754 static void crypt_resume(struct dm_target *ti) 1755 { 1756 struct crypt_config *cc = ti->private; 1757 1758 clear_bit(DM_CRYPT_SUSPENDED, &cc->flags); 1759 } 1760 1761 /* Message interface 1762 * key set <key> 1763 * key wipe 1764 */ 1765 static int crypt_message(struct dm_target *ti, unsigned argc, char **argv) 1766 { 1767 struct crypt_config *cc = ti->private; 1768 int ret = -EINVAL; 1769 1770 if (argc < 2) 1771 goto error; 1772 1773 if (!strnicmp(argv[0], MESG_STR("key"))) { 1774 if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) { 1775 DMWARN("not suspended during key manipulation."); 1776 return -EINVAL; 1777 } 1778 if (argc == 3 && !strnicmp(argv[1], MESG_STR("set"))) { 1779 ret = crypt_set_key(cc, argv[2]); 1780 if (ret) 1781 return ret; 1782 if (cc->iv_gen_ops && cc->iv_gen_ops->init) 1783 ret = cc->iv_gen_ops->init(cc); 1784 return ret; 1785 } 1786 if (argc == 2 && !strnicmp(argv[1], MESG_STR("wipe"))) { 1787 if (cc->iv_gen_ops && cc->iv_gen_ops->wipe) { 1788 ret = cc->iv_gen_ops->wipe(cc); 1789 if (ret) 1790 return ret; 1791 } 1792 return crypt_wipe_key(cc); 1793 } 1794 } 1795 1796 error: 1797 DMWARN("unrecognised message received."); 1798 return -EINVAL; 1799 } 1800 1801 static int crypt_merge(struct dm_target *ti, struct bvec_merge_data *bvm, 1802 struct bio_vec *biovec, int max_size) 1803 { 1804 struct crypt_config *cc = ti->private; 1805 struct request_queue *q = bdev_get_queue(cc->dev->bdev); 1806 1807 if (!q->merge_bvec_fn) 1808 return max_size; 1809 1810 bvm->bi_bdev = cc->dev->bdev; 1811 bvm->bi_sector = cc->start + dm_target_offset(ti, bvm->bi_sector); 1812 1813 return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); 1814 } 1815 1816 static int crypt_iterate_devices(struct dm_target *ti, 1817 iterate_devices_callout_fn fn, void *data) 1818 { 1819 struct crypt_config *cc = ti->private; 1820 1821 return fn(ti, cc->dev, cc->start, ti->len, data); 1822 } 1823 1824 static struct target_type crypt_target = { 1825 .name = "crypt", 1826 .version = {1, 10, 0}, 1827 .module = THIS_MODULE, 1828 .ctr = crypt_ctr, 1829 .dtr = crypt_dtr, 1830 .map = crypt_map, 1831 .status = crypt_status, 1832 .postsuspend = crypt_postsuspend, 1833 .preresume = crypt_preresume, 1834 .resume = crypt_resume, 1835 .message = crypt_message, 1836 .merge = crypt_merge, 1837 .iterate_devices = crypt_iterate_devices, 1838 }; 1839 1840 static int __init dm_crypt_init(void) 1841 { 1842 int r; 1843 1844 _crypt_io_pool = KMEM_CACHE(dm_crypt_io, 0); 1845 if (!_crypt_io_pool) 1846 return -ENOMEM; 1847 1848 r = dm_register_target(&crypt_target); 1849 if (r < 0) { 1850 DMERR("register failed %d", r); 1851 kmem_cache_destroy(_crypt_io_pool); 1852 } 1853 1854 return r; 1855 } 1856 1857 static void __exit dm_crypt_exit(void) 1858 { 1859 dm_unregister_target(&crypt_target); 1860 kmem_cache_destroy(_crypt_io_pool); 1861 } 1862 1863 module_init(dm_crypt_init); 1864 module_exit(dm_crypt_exit); 1865 1866 MODULE_AUTHOR("Christophe Saout <christophe@saout.de>"); 1867 MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption"); 1868 MODULE_LICENSE("GPL"); 1869