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 static void dm_crypt_bio_destructor(struct bio *bio) 802 { 803 struct dm_crypt_io *io = bio->bi_private; 804 struct crypt_config *cc = io->cc; 805 806 bio_free(bio, cc->bs); 807 } 808 809 /* 810 * Generate a new unfragmented bio with the given size 811 * This should never violate the device limitations 812 * May return a smaller bio when running out of pages, indicated by 813 * *out_of_pages set to 1. 814 */ 815 static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size, 816 unsigned *out_of_pages) 817 { 818 struct crypt_config *cc = io->cc; 819 struct bio *clone; 820 unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; 821 gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM; 822 unsigned i, len; 823 struct page *page; 824 825 clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs); 826 if (!clone) 827 return NULL; 828 829 clone_init(io, clone); 830 *out_of_pages = 0; 831 832 for (i = 0; i < nr_iovecs; i++) { 833 page = mempool_alloc(cc->page_pool, gfp_mask); 834 if (!page) { 835 *out_of_pages = 1; 836 break; 837 } 838 839 /* 840 * If additional pages cannot be allocated without waiting, 841 * return a partially-allocated bio. The caller will then try 842 * to allocate more bios while submitting this partial bio. 843 */ 844 gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT; 845 846 len = (size > PAGE_SIZE) ? PAGE_SIZE : size; 847 848 if (!bio_add_page(clone, page, len, 0)) { 849 mempool_free(page, cc->page_pool); 850 break; 851 } 852 853 size -= len; 854 } 855 856 if (!clone->bi_size) { 857 bio_put(clone); 858 return NULL; 859 } 860 861 return clone; 862 } 863 864 static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone) 865 { 866 unsigned int i; 867 struct bio_vec *bv; 868 869 for (i = 0; i < clone->bi_vcnt; i++) { 870 bv = bio_iovec_idx(clone, i); 871 BUG_ON(!bv->bv_page); 872 mempool_free(bv->bv_page, cc->page_pool); 873 bv->bv_page = NULL; 874 } 875 } 876 877 static struct dm_crypt_io *crypt_io_alloc(struct crypt_config *cc, 878 struct bio *bio, sector_t sector) 879 { 880 struct dm_crypt_io *io; 881 882 io = mempool_alloc(cc->io_pool, GFP_NOIO); 883 io->cc = cc; 884 io->base_bio = bio; 885 io->sector = sector; 886 io->error = 0; 887 io->base_io = NULL; 888 atomic_set(&io->io_pending, 0); 889 890 return io; 891 } 892 893 static void crypt_inc_pending(struct dm_crypt_io *io) 894 { 895 atomic_inc(&io->io_pending); 896 } 897 898 /* 899 * One of the bios was finished. Check for completion of 900 * the whole request and correctly clean up the buffer. 901 * If base_io is set, wait for the last fragment to complete. 902 */ 903 static void crypt_dec_pending(struct dm_crypt_io *io) 904 { 905 struct crypt_config *cc = io->cc; 906 struct bio *base_bio = io->base_bio; 907 struct dm_crypt_io *base_io = io->base_io; 908 int error = io->error; 909 910 if (!atomic_dec_and_test(&io->io_pending)) 911 return; 912 913 mempool_free(io, cc->io_pool); 914 915 if (likely(!base_io)) 916 bio_endio(base_bio, error); 917 else { 918 if (error && !base_io->error) 919 base_io->error = error; 920 crypt_dec_pending(base_io); 921 } 922 } 923 924 /* 925 * kcryptd/kcryptd_io: 926 * 927 * Needed because it would be very unwise to do decryption in an 928 * interrupt context. 929 * 930 * kcryptd performs the actual encryption or decryption. 931 * 932 * kcryptd_io performs the IO submission. 933 * 934 * They must be separated as otherwise the final stages could be 935 * starved by new requests which can block in the first stages due 936 * to memory allocation. 937 * 938 * The work is done per CPU global for all dm-crypt instances. 939 * They should not depend on each other and do not block. 940 */ 941 static void crypt_endio(struct bio *clone, int error) 942 { 943 struct dm_crypt_io *io = clone->bi_private; 944 struct crypt_config *cc = io->cc; 945 unsigned rw = bio_data_dir(clone); 946 947 if (unlikely(!bio_flagged(clone, BIO_UPTODATE) && !error)) 948 error = -EIO; 949 950 /* 951 * free the processed pages 952 */ 953 if (rw == WRITE) 954 crypt_free_buffer_pages(cc, clone); 955 956 bio_put(clone); 957 958 if (rw == READ && !error) { 959 kcryptd_queue_crypt(io); 960 return; 961 } 962 963 if (unlikely(error)) 964 io->error = error; 965 966 crypt_dec_pending(io); 967 } 968 969 static void clone_init(struct dm_crypt_io *io, struct bio *clone) 970 { 971 struct crypt_config *cc = io->cc; 972 973 clone->bi_private = io; 974 clone->bi_end_io = crypt_endio; 975 clone->bi_bdev = cc->dev->bdev; 976 clone->bi_rw = io->base_bio->bi_rw; 977 clone->bi_destructor = dm_crypt_bio_destructor; 978 } 979 980 static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp) 981 { 982 struct crypt_config *cc = io->cc; 983 struct bio *base_bio = io->base_bio; 984 struct bio *clone; 985 986 /* 987 * The block layer might modify the bvec array, so always 988 * copy the required bvecs because we need the original 989 * one in order to decrypt the whole bio data *afterwards*. 990 */ 991 clone = bio_alloc_bioset(gfp, bio_segments(base_bio), cc->bs); 992 if (!clone) 993 return 1; 994 995 crypt_inc_pending(io); 996 997 clone_init(io, clone); 998 clone->bi_idx = 0; 999 clone->bi_vcnt = bio_segments(base_bio); 1000 clone->bi_size = base_bio->bi_size; 1001 clone->bi_sector = cc->start + io->sector; 1002 memcpy(clone->bi_io_vec, bio_iovec(base_bio), 1003 sizeof(struct bio_vec) * clone->bi_vcnt); 1004 1005 generic_make_request(clone); 1006 return 0; 1007 } 1008 1009 static void kcryptd_io_write(struct dm_crypt_io *io) 1010 { 1011 struct bio *clone = io->ctx.bio_out; 1012 generic_make_request(clone); 1013 } 1014 1015 static void kcryptd_io(struct work_struct *work) 1016 { 1017 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work); 1018 1019 if (bio_data_dir(io->base_bio) == READ) { 1020 crypt_inc_pending(io); 1021 if (kcryptd_io_read(io, GFP_NOIO)) 1022 io->error = -ENOMEM; 1023 crypt_dec_pending(io); 1024 } else 1025 kcryptd_io_write(io); 1026 } 1027 1028 static void kcryptd_queue_io(struct dm_crypt_io *io) 1029 { 1030 struct crypt_config *cc = io->cc; 1031 1032 INIT_WORK(&io->work, kcryptd_io); 1033 queue_work(cc->io_queue, &io->work); 1034 } 1035 1036 static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io, int async) 1037 { 1038 struct bio *clone = io->ctx.bio_out; 1039 struct crypt_config *cc = io->cc; 1040 1041 if (unlikely(io->error < 0)) { 1042 crypt_free_buffer_pages(cc, clone); 1043 bio_put(clone); 1044 crypt_dec_pending(io); 1045 return; 1046 } 1047 1048 /* crypt_convert should have filled the clone bio */ 1049 BUG_ON(io->ctx.idx_out < clone->bi_vcnt); 1050 1051 clone->bi_sector = cc->start + io->sector; 1052 1053 if (async) 1054 kcryptd_queue_io(io); 1055 else 1056 generic_make_request(clone); 1057 } 1058 1059 static void kcryptd_crypt_write_convert(struct dm_crypt_io *io) 1060 { 1061 struct crypt_config *cc = io->cc; 1062 struct bio *clone; 1063 struct dm_crypt_io *new_io; 1064 int crypt_finished; 1065 unsigned out_of_pages = 0; 1066 unsigned remaining = io->base_bio->bi_size; 1067 sector_t sector = io->sector; 1068 int r; 1069 1070 /* 1071 * Prevent io from disappearing until this function completes. 1072 */ 1073 crypt_inc_pending(io); 1074 crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, sector); 1075 1076 /* 1077 * The allocated buffers can be smaller than the whole bio, 1078 * so repeat the whole process until all the data can be handled. 1079 */ 1080 while (remaining) { 1081 clone = crypt_alloc_buffer(io, remaining, &out_of_pages); 1082 if (unlikely(!clone)) { 1083 io->error = -ENOMEM; 1084 break; 1085 } 1086 1087 io->ctx.bio_out = clone; 1088 io->ctx.idx_out = 0; 1089 1090 remaining -= clone->bi_size; 1091 sector += bio_sectors(clone); 1092 1093 crypt_inc_pending(io); 1094 1095 r = crypt_convert(cc, &io->ctx); 1096 if (r < 0) 1097 io->error = -EIO; 1098 1099 crypt_finished = atomic_dec_and_test(&io->ctx.cc_pending); 1100 1101 /* Encryption was already finished, submit io now */ 1102 if (crypt_finished) { 1103 kcryptd_crypt_write_io_submit(io, 0); 1104 1105 /* 1106 * If there was an error, do not try next fragments. 1107 * For async, error is processed in async handler. 1108 */ 1109 if (unlikely(r < 0)) 1110 break; 1111 1112 io->sector = sector; 1113 } 1114 1115 /* 1116 * Out of memory -> run queues 1117 * But don't wait if split was due to the io size restriction 1118 */ 1119 if (unlikely(out_of_pages)) 1120 congestion_wait(BLK_RW_ASYNC, HZ/100); 1121 1122 /* 1123 * With async crypto it is unsafe to share the crypto context 1124 * between fragments, so switch to a new dm_crypt_io structure. 1125 */ 1126 if (unlikely(!crypt_finished && remaining)) { 1127 new_io = crypt_io_alloc(io->cc, io->base_bio, 1128 sector); 1129 crypt_inc_pending(new_io); 1130 crypt_convert_init(cc, &new_io->ctx, NULL, 1131 io->base_bio, sector); 1132 new_io->ctx.idx_in = io->ctx.idx_in; 1133 new_io->ctx.offset_in = io->ctx.offset_in; 1134 1135 /* 1136 * Fragments after the first use the base_io 1137 * pending count. 1138 */ 1139 if (!io->base_io) 1140 new_io->base_io = io; 1141 else { 1142 new_io->base_io = io->base_io; 1143 crypt_inc_pending(io->base_io); 1144 crypt_dec_pending(io); 1145 } 1146 1147 io = new_io; 1148 } 1149 } 1150 1151 crypt_dec_pending(io); 1152 } 1153 1154 static void kcryptd_crypt_read_done(struct dm_crypt_io *io) 1155 { 1156 crypt_dec_pending(io); 1157 } 1158 1159 static void kcryptd_crypt_read_convert(struct dm_crypt_io *io) 1160 { 1161 struct crypt_config *cc = io->cc; 1162 int r = 0; 1163 1164 crypt_inc_pending(io); 1165 1166 crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio, 1167 io->sector); 1168 1169 r = crypt_convert(cc, &io->ctx); 1170 if (r < 0) 1171 io->error = -EIO; 1172 1173 if (atomic_dec_and_test(&io->ctx.cc_pending)) 1174 kcryptd_crypt_read_done(io); 1175 1176 crypt_dec_pending(io); 1177 } 1178 1179 static void kcryptd_async_done(struct crypto_async_request *async_req, 1180 int error) 1181 { 1182 struct dm_crypt_request *dmreq = async_req->data; 1183 struct convert_context *ctx = dmreq->ctx; 1184 struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx); 1185 struct crypt_config *cc = io->cc; 1186 1187 if (error == -EINPROGRESS) { 1188 complete(&ctx->restart); 1189 return; 1190 } 1191 1192 if (!error && cc->iv_gen_ops && cc->iv_gen_ops->post) 1193 error = cc->iv_gen_ops->post(cc, iv_of_dmreq(cc, dmreq), dmreq); 1194 1195 if (error < 0) 1196 io->error = -EIO; 1197 1198 mempool_free(req_of_dmreq(cc, dmreq), cc->req_pool); 1199 1200 if (!atomic_dec_and_test(&ctx->cc_pending)) 1201 return; 1202 1203 if (bio_data_dir(io->base_bio) == READ) 1204 kcryptd_crypt_read_done(io); 1205 else 1206 kcryptd_crypt_write_io_submit(io, 1); 1207 } 1208 1209 static void kcryptd_crypt(struct work_struct *work) 1210 { 1211 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work); 1212 1213 if (bio_data_dir(io->base_bio) == READ) 1214 kcryptd_crypt_read_convert(io); 1215 else 1216 kcryptd_crypt_write_convert(io); 1217 } 1218 1219 static void kcryptd_queue_crypt(struct dm_crypt_io *io) 1220 { 1221 struct crypt_config *cc = io->cc; 1222 1223 INIT_WORK(&io->work, kcryptd_crypt); 1224 queue_work(cc->crypt_queue, &io->work); 1225 } 1226 1227 /* 1228 * Decode key from its hex representation 1229 */ 1230 static int crypt_decode_key(u8 *key, char *hex, unsigned int size) 1231 { 1232 char buffer[3]; 1233 unsigned int i; 1234 1235 buffer[2] = '\0'; 1236 1237 for (i = 0; i < size; i++) { 1238 buffer[0] = *hex++; 1239 buffer[1] = *hex++; 1240 1241 if (kstrtou8(buffer, 16, &key[i])) 1242 return -EINVAL; 1243 } 1244 1245 if (*hex != '\0') 1246 return -EINVAL; 1247 1248 return 0; 1249 } 1250 1251 /* 1252 * Encode key into its hex representation 1253 */ 1254 static void crypt_encode_key(char *hex, u8 *key, unsigned int size) 1255 { 1256 unsigned int i; 1257 1258 for (i = 0; i < size; i++) { 1259 sprintf(hex, "%02x", *key); 1260 hex += 2; 1261 key++; 1262 } 1263 } 1264 1265 static void crypt_free_tfms(struct crypt_config *cc) 1266 { 1267 unsigned i; 1268 1269 if (!cc->tfms) 1270 return; 1271 1272 for (i = 0; i < cc->tfms_count; i++) 1273 if (cc->tfms[i] && !IS_ERR(cc->tfms[i])) { 1274 crypto_free_ablkcipher(cc->tfms[i]); 1275 cc->tfms[i] = NULL; 1276 } 1277 1278 kfree(cc->tfms); 1279 cc->tfms = NULL; 1280 } 1281 1282 static int crypt_alloc_tfms(struct crypt_config *cc, char *ciphermode) 1283 { 1284 unsigned i; 1285 int err; 1286 1287 cc->tfms = kmalloc(cc->tfms_count * sizeof(struct crypto_ablkcipher *), 1288 GFP_KERNEL); 1289 if (!cc->tfms) 1290 return -ENOMEM; 1291 1292 for (i = 0; i < cc->tfms_count; i++) { 1293 cc->tfms[i] = crypto_alloc_ablkcipher(ciphermode, 0, 0); 1294 if (IS_ERR(cc->tfms[i])) { 1295 err = PTR_ERR(cc->tfms[i]); 1296 crypt_free_tfms(cc); 1297 return err; 1298 } 1299 } 1300 1301 return 0; 1302 } 1303 1304 static int crypt_setkey_allcpus(struct crypt_config *cc) 1305 { 1306 unsigned subkey_size = cc->key_size >> ilog2(cc->tfms_count); 1307 int err = 0, i, r; 1308 1309 for (i = 0; i < cc->tfms_count; i++) { 1310 r = crypto_ablkcipher_setkey(cc->tfms[i], 1311 cc->key + (i * subkey_size), 1312 subkey_size); 1313 if (r) 1314 err = r; 1315 } 1316 1317 return err; 1318 } 1319 1320 static int crypt_set_key(struct crypt_config *cc, char *key) 1321 { 1322 int r = -EINVAL; 1323 int key_string_len = strlen(key); 1324 1325 /* The key size may not be changed. */ 1326 if (cc->key_size != (key_string_len >> 1)) 1327 goto out; 1328 1329 /* Hyphen (which gives a key_size of zero) means there is no key. */ 1330 if (!cc->key_size && strcmp(key, "-")) 1331 goto out; 1332 1333 if (cc->key_size && crypt_decode_key(cc->key, key, cc->key_size) < 0) 1334 goto out; 1335 1336 set_bit(DM_CRYPT_KEY_VALID, &cc->flags); 1337 1338 r = crypt_setkey_allcpus(cc); 1339 1340 out: 1341 /* Hex key string not needed after here, so wipe it. */ 1342 memset(key, '0', key_string_len); 1343 1344 return r; 1345 } 1346 1347 static int crypt_wipe_key(struct crypt_config *cc) 1348 { 1349 clear_bit(DM_CRYPT_KEY_VALID, &cc->flags); 1350 memset(&cc->key, 0, cc->key_size * sizeof(u8)); 1351 1352 return crypt_setkey_allcpus(cc); 1353 } 1354 1355 static void crypt_dtr(struct dm_target *ti) 1356 { 1357 struct crypt_config *cc = ti->private; 1358 struct crypt_cpu *cpu_cc; 1359 int cpu; 1360 1361 ti->private = NULL; 1362 1363 if (!cc) 1364 return; 1365 1366 if (cc->io_queue) 1367 destroy_workqueue(cc->io_queue); 1368 if (cc->crypt_queue) 1369 destroy_workqueue(cc->crypt_queue); 1370 1371 if (cc->cpu) 1372 for_each_possible_cpu(cpu) { 1373 cpu_cc = per_cpu_ptr(cc->cpu, cpu); 1374 if (cpu_cc->req) 1375 mempool_free(cpu_cc->req, cc->req_pool); 1376 } 1377 1378 crypt_free_tfms(cc); 1379 1380 if (cc->bs) 1381 bioset_free(cc->bs); 1382 1383 if (cc->page_pool) 1384 mempool_destroy(cc->page_pool); 1385 if (cc->req_pool) 1386 mempool_destroy(cc->req_pool); 1387 if (cc->io_pool) 1388 mempool_destroy(cc->io_pool); 1389 1390 if (cc->iv_gen_ops && cc->iv_gen_ops->dtr) 1391 cc->iv_gen_ops->dtr(cc); 1392 1393 if (cc->dev) 1394 dm_put_device(ti, cc->dev); 1395 1396 if (cc->cpu) 1397 free_percpu(cc->cpu); 1398 1399 kzfree(cc->cipher); 1400 kzfree(cc->cipher_string); 1401 1402 /* Must zero key material before freeing */ 1403 kzfree(cc); 1404 } 1405 1406 static int crypt_ctr_cipher(struct dm_target *ti, 1407 char *cipher_in, char *key) 1408 { 1409 struct crypt_config *cc = ti->private; 1410 char *tmp, *cipher, *chainmode, *ivmode, *ivopts, *keycount; 1411 char *cipher_api = NULL; 1412 int ret = -EINVAL; 1413 char dummy; 1414 1415 /* Convert to crypto api definition? */ 1416 if (strchr(cipher_in, '(')) { 1417 ti->error = "Bad cipher specification"; 1418 return -EINVAL; 1419 } 1420 1421 cc->cipher_string = kstrdup(cipher_in, GFP_KERNEL); 1422 if (!cc->cipher_string) 1423 goto bad_mem; 1424 1425 /* 1426 * Legacy dm-crypt cipher specification 1427 * cipher[:keycount]-mode-iv:ivopts 1428 */ 1429 tmp = cipher_in; 1430 keycount = strsep(&tmp, "-"); 1431 cipher = strsep(&keycount, ":"); 1432 1433 if (!keycount) 1434 cc->tfms_count = 1; 1435 else if (sscanf(keycount, "%u%c", &cc->tfms_count, &dummy) != 1 || 1436 !is_power_of_2(cc->tfms_count)) { 1437 ti->error = "Bad cipher key count specification"; 1438 return -EINVAL; 1439 } 1440 cc->key_parts = cc->tfms_count; 1441 1442 cc->cipher = kstrdup(cipher, GFP_KERNEL); 1443 if (!cc->cipher) 1444 goto bad_mem; 1445 1446 chainmode = strsep(&tmp, "-"); 1447 ivopts = strsep(&tmp, "-"); 1448 ivmode = strsep(&ivopts, ":"); 1449 1450 if (tmp) 1451 DMWARN("Ignoring unexpected additional cipher options"); 1452 1453 cc->cpu = __alloc_percpu(sizeof(*(cc->cpu)), 1454 __alignof__(struct crypt_cpu)); 1455 if (!cc->cpu) { 1456 ti->error = "Cannot allocate per cpu state"; 1457 goto bad_mem; 1458 } 1459 1460 /* 1461 * For compatibility with the original dm-crypt mapping format, if 1462 * only the cipher name is supplied, use cbc-plain. 1463 */ 1464 if (!chainmode || (!strcmp(chainmode, "plain") && !ivmode)) { 1465 chainmode = "cbc"; 1466 ivmode = "plain"; 1467 } 1468 1469 if (strcmp(chainmode, "ecb") && !ivmode) { 1470 ti->error = "IV mechanism required"; 1471 return -EINVAL; 1472 } 1473 1474 cipher_api = kmalloc(CRYPTO_MAX_ALG_NAME, GFP_KERNEL); 1475 if (!cipher_api) 1476 goto bad_mem; 1477 1478 ret = snprintf(cipher_api, CRYPTO_MAX_ALG_NAME, 1479 "%s(%s)", chainmode, cipher); 1480 if (ret < 0) { 1481 kfree(cipher_api); 1482 goto bad_mem; 1483 } 1484 1485 /* Allocate cipher */ 1486 ret = crypt_alloc_tfms(cc, cipher_api); 1487 if (ret < 0) { 1488 ti->error = "Error allocating crypto tfm"; 1489 goto bad; 1490 } 1491 1492 /* Initialize and set key */ 1493 ret = crypt_set_key(cc, key); 1494 if (ret < 0) { 1495 ti->error = "Error decoding and setting key"; 1496 goto bad; 1497 } 1498 1499 /* Initialize IV */ 1500 cc->iv_size = crypto_ablkcipher_ivsize(any_tfm(cc)); 1501 if (cc->iv_size) 1502 /* at least a 64 bit sector number should fit in our buffer */ 1503 cc->iv_size = max(cc->iv_size, 1504 (unsigned int)(sizeof(u64) / sizeof(u8))); 1505 else if (ivmode) { 1506 DMWARN("Selected cipher does not support IVs"); 1507 ivmode = NULL; 1508 } 1509 1510 /* Choose ivmode, see comments at iv code. */ 1511 if (ivmode == NULL) 1512 cc->iv_gen_ops = NULL; 1513 else if (strcmp(ivmode, "plain") == 0) 1514 cc->iv_gen_ops = &crypt_iv_plain_ops; 1515 else if (strcmp(ivmode, "plain64") == 0) 1516 cc->iv_gen_ops = &crypt_iv_plain64_ops; 1517 else if (strcmp(ivmode, "essiv") == 0) 1518 cc->iv_gen_ops = &crypt_iv_essiv_ops; 1519 else if (strcmp(ivmode, "benbi") == 0) 1520 cc->iv_gen_ops = &crypt_iv_benbi_ops; 1521 else if (strcmp(ivmode, "null") == 0) 1522 cc->iv_gen_ops = &crypt_iv_null_ops; 1523 else if (strcmp(ivmode, "lmk") == 0) { 1524 cc->iv_gen_ops = &crypt_iv_lmk_ops; 1525 /* Version 2 and 3 is recognised according 1526 * to length of provided multi-key string. 1527 * If present (version 3), last key is used as IV seed. 1528 */ 1529 if (cc->key_size % cc->key_parts) 1530 cc->key_parts++; 1531 } else { 1532 ret = -EINVAL; 1533 ti->error = "Invalid IV mode"; 1534 goto bad; 1535 } 1536 1537 /* Allocate IV */ 1538 if (cc->iv_gen_ops && cc->iv_gen_ops->ctr) { 1539 ret = cc->iv_gen_ops->ctr(cc, ti, ivopts); 1540 if (ret < 0) { 1541 ti->error = "Error creating IV"; 1542 goto bad; 1543 } 1544 } 1545 1546 /* Initialize IV (set keys for ESSIV etc) */ 1547 if (cc->iv_gen_ops && cc->iv_gen_ops->init) { 1548 ret = cc->iv_gen_ops->init(cc); 1549 if (ret < 0) { 1550 ti->error = "Error initialising IV"; 1551 goto bad; 1552 } 1553 } 1554 1555 ret = 0; 1556 bad: 1557 kfree(cipher_api); 1558 return ret; 1559 1560 bad_mem: 1561 ti->error = "Cannot allocate cipher strings"; 1562 return -ENOMEM; 1563 } 1564 1565 /* 1566 * Construct an encryption mapping: 1567 * <cipher> <key> <iv_offset> <dev_path> <start> 1568 */ 1569 static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv) 1570 { 1571 struct crypt_config *cc; 1572 unsigned int key_size, opt_params; 1573 unsigned long long tmpll; 1574 int ret; 1575 struct dm_arg_set as; 1576 const char *opt_string; 1577 char dummy; 1578 1579 static struct dm_arg _args[] = { 1580 {0, 1, "Invalid number of feature args"}, 1581 }; 1582 1583 if (argc < 5) { 1584 ti->error = "Not enough arguments"; 1585 return -EINVAL; 1586 } 1587 1588 key_size = strlen(argv[1]) >> 1; 1589 1590 cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL); 1591 if (!cc) { 1592 ti->error = "Cannot allocate encryption context"; 1593 return -ENOMEM; 1594 } 1595 cc->key_size = key_size; 1596 1597 ti->private = cc; 1598 ret = crypt_ctr_cipher(ti, argv[0], argv[1]); 1599 if (ret < 0) 1600 goto bad; 1601 1602 ret = -ENOMEM; 1603 cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool); 1604 if (!cc->io_pool) { 1605 ti->error = "Cannot allocate crypt io mempool"; 1606 goto bad; 1607 } 1608 1609 cc->dmreq_start = sizeof(struct ablkcipher_request); 1610 cc->dmreq_start += crypto_ablkcipher_reqsize(any_tfm(cc)); 1611 cc->dmreq_start = ALIGN(cc->dmreq_start, crypto_tfm_ctx_alignment()); 1612 cc->dmreq_start += crypto_ablkcipher_alignmask(any_tfm(cc)) & 1613 ~(crypto_tfm_ctx_alignment() - 1); 1614 1615 cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start + 1616 sizeof(struct dm_crypt_request) + cc->iv_size); 1617 if (!cc->req_pool) { 1618 ti->error = "Cannot allocate crypt request mempool"; 1619 goto bad; 1620 } 1621 1622 cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0); 1623 if (!cc->page_pool) { 1624 ti->error = "Cannot allocate page mempool"; 1625 goto bad; 1626 } 1627 1628 cc->bs = bioset_create(MIN_IOS, 0); 1629 if (!cc->bs) { 1630 ti->error = "Cannot allocate crypt bioset"; 1631 goto bad; 1632 } 1633 1634 ret = -EINVAL; 1635 if (sscanf(argv[2], "%llu%c", &tmpll, &dummy) != 1) { 1636 ti->error = "Invalid iv_offset sector"; 1637 goto bad; 1638 } 1639 cc->iv_offset = tmpll; 1640 1641 if (dm_get_device(ti, argv[3], dm_table_get_mode(ti->table), &cc->dev)) { 1642 ti->error = "Device lookup failed"; 1643 goto bad; 1644 } 1645 1646 if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1) { 1647 ti->error = "Invalid device sector"; 1648 goto bad; 1649 } 1650 cc->start = tmpll; 1651 1652 argv += 5; 1653 argc -= 5; 1654 1655 /* Optional parameters */ 1656 if (argc) { 1657 as.argc = argc; 1658 as.argv = argv; 1659 1660 ret = dm_read_arg_group(_args, &as, &opt_params, &ti->error); 1661 if (ret) 1662 goto bad; 1663 1664 opt_string = dm_shift_arg(&as); 1665 1666 if (opt_params == 1 && opt_string && 1667 !strcasecmp(opt_string, "allow_discards")) 1668 ti->num_discard_requests = 1; 1669 else if (opt_params) { 1670 ret = -EINVAL; 1671 ti->error = "Invalid feature arguments"; 1672 goto bad; 1673 } 1674 } 1675 1676 ret = -ENOMEM; 1677 cc->io_queue = alloc_workqueue("kcryptd_io", 1678 WQ_NON_REENTRANT| 1679 WQ_MEM_RECLAIM, 1680 1); 1681 if (!cc->io_queue) { 1682 ti->error = "Couldn't create kcryptd io queue"; 1683 goto bad; 1684 } 1685 1686 cc->crypt_queue = alloc_workqueue("kcryptd", 1687 WQ_NON_REENTRANT| 1688 WQ_CPU_INTENSIVE| 1689 WQ_MEM_RECLAIM, 1690 1); 1691 if (!cc->crypt_queue) { 1692 ti->error = "Couldn't create kcryptd queue"; 1693 goto bad; 1694 } 1695 1696 ti->num_flush_requests = 1; 1697 ti->discard_zeroes_data_unsupported = true; 1698 1699 return 0; 1700 1701 bad: 1702 crypt_dtr(ti); 1703 return ret; 1704 } 1705 1706 static int crypt_map(struct dm_target *ti, struct bio *bio, 1707 union map_info *map_context) 1708 { 1709 struct dm_crypt_io *io; 1710 struct crypt_config *cc = ti->private; 1711 1712 /* 1713 * If bio is REQ_FLUSH or REQ_DISCARD, just bypass crypt queues. 1714 * - for REQ_FLUSH device-mapper core ensures that no IO is in-flight 1715 * - for REQ_DISCARD caller must use flush if IO ordering matters 1716 */ 1717 if (unlikely(bio->bi_rw & (REQ_FLUSH | REQ_DISCARD))) { 1718 bio->bi_bdev = cc->dev->bdev; 1719 if (bio_sectors(bio)) 1720 bio->bi_sector = cc->start + dm_target_offset(ti, bio->bi_sector); 1721 return DM_MAPIO_REMAPPED; 1722 } 1723 1724 io = crypt_io_alloc(cc, bio, dm_target_offset(ti, bio->bi_sector)); 1725 1726 if (bio_data_dir(io->base_bio) == READ) { 1727 if (kcryptd_io_read(io, GFP_NOWAIT)) 1728 kcryptd_queue_io(io); 1729 } else 1730 kcryptd_queue_crypt(io); 1731 1732 return DM_MAPIO_SUBMITTED; 1733 } 1734 1735 static int crypt_status(struct dm_target *ti, status_type_t type, 1736 unsigned status_flags, char *result, unsigned maxlen) 1737 { 1738 struct crypt_config *cc = ti->private; 1739 unsigned int sz = 0; 1740 1741 switch (type) { 1742 case STATUSTYPE_INFO: 1743 result[0] = '\0'; 1744 break; 1745 1746 case STATUSTYPE_TABLE: 1747 DMEMIT("%s ", cc->cipher_string); 1748 1749 if (cc->key_size > 0) { 1750 if ((maxlen - sz) < ((cc->key_size << 1) + 1)) 1751 return -ENOMEM; 1752 1753 crypt_encode_key(result + sz, cc->key, cc->key_size); 1754 sz += cc->key_size << 1; 1755 } else { 1756 if (sz >= maxlen) 1757 return -ENOMEM; 1758 result[sz++] = '-'; 1759 } 1760 1761 DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset, 1762 cc->dev->name, (unsigned long long)cc->start); 1763 1764 if (ti->num_discard_requests) 1765 DMEMIT(" 1 allow_discards"); 1766 1767 break; 1768 } 1769 return 0; 1770 } 1771 1772 static void crypt_postsuspend(struct dm_target *ti) 1773 { 1774 struct crypt_config *cc = ti->private; 1775 1776 set_bit(DM_CRYPT_SUSPENDED, &cc->flags); 1777 } 1778 1779 static int crypt_preresume(struct dm_target *ti) 1780 { 1781 struct crypt_config *cc = ti->private; 1782 1783 if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) { 1784 DMERR("aborting resume - crypt key is not set."); 1785 return -EAGAIN; 1786 } 1787 1788 return 0; 1789 } 1790 1791 static void crypt_resume(struct dm_target *ti) 1792 { 1793 struct crypt_config *cc = ti->private; 1794 1795 clear_bit(DM_CRYPT_SUSPENDED, &cc->flags); 1796 } 1797 1798 /* Message interface 1799 * key set <key> 1800 * key wipe 1801 */ 1802 static int crypt_message(struct dm_target *ti, unsigned argc, char **argv) 1803 { 1804 struct crypt_config *cc = ti->private; 1805 int ret = -EINVAL; 1806 1807 if (argc < 2) 1808 goto error; 1809 1810 if (!strcasecmp(argv[0], "key")) { 1811 if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) { 1812 DMWARN("not suspended during key manipulation."); 1813 return -EINVAL; 1814 } 1815 if (argc == 3 && !strcasecmp(argv[1], "set")) { 1816 ret = crypt_set_key(cc, argv[2]); 1817 if (ret) 1818 return ret; 1819 if (cc->iv_gen_ops && cc->iv_gen_ops->init) 1820 ret = cc->iv_gen_ops->init(cc); 1821 return ret; 1822 } 1823 if (argc == 2 && !strcasecmp(argv[1], "wipe")) { 1824 if (cc->iv_gen_ops && cc->iv_gen_ops->wipe) { 1825 ret = cc->iv_gen_ops->wipe(cc); 1826 if (ret) 1827 return ret; 1828 } 1829 return crypt_wipe_key(cc); 1830 } 1831 } 1832 1833 error: 1834 DMWARN("unrecognised message received."); 1835 return -EINVAL; 1836 } 1837 1838 static int crypt_merge(struct dm_target *ti, struct bvec_merge_data *bvm, 1839 struct bio_vec *biovec, int max_size) 1840 { 1841 struct crypt_config *cc = ti->private; 1842 struct request_queue *q = bdev_get_queue(cc->dev->bdev); 1843 1844 if (!q->merge_bvec_fn) 1845 return max_size; 1846 1847 bvm->bi_bdev = cc->dev->bdev; 1848 bvm->bi_sector = cc->start + dm_target_offset(ti, bvm->bi_sector); 1849 1850 return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); 1851 } 1852 1853 static int crypt_iterate_devices(struct dm_target *ti, 1854 iterate_devices_callout_fn fn, void *data) 1855 { 1856 struct crypt_config *cc = ti->private; 1857 1858 return fn(ti, cc->dev, cc->start, ti->len, data); 1859 } 1860 1861 static struct target_type crypt_target = { 1862 .name = "crypt", 1863 .version = {1, 11, 0}, 1864 .module = THIS_MODULE, 1865 .ctr = crypt_ctr, 1866 .dtr = crypt_dtr, 1867 .map = crypt_map, 1868 .status = crypt_status, 1869 .postsuspend = crypt_postsuspend, 1870 .preresume = crypt_preresume, 1871 .resume = crypt_resume, 1872 .message = crypt_message, 1873 .merge = crypt_merge, 1874 .iterate_devices = crypt_iterate_devices, 1875 }; 1876 1877 static int __init dm_crypt_init(void) 1878 { 1879 int r; 1880 1881 _crypt_io_pool = KMEM_CACHE(dm_crypt_io, 0); 1882 if (!_crypt_io_pool) 1883 return -ENOMEM; 1884 1885 r = dm_register_target(&crypt_target); 1886 if (r < 0) { 1887 DMERR("register failed %d", r); 1888 kmem_cache_destroy(_crypt_io_pool); 1889 } 1890 1891 return r; 1892 } 1893 1894 static void __exit dm_crypt_exit(void) 1895 { 1896 dm_unregister_target(&crypt_target); 1897 kmem_cache_destroy(_crypt_io_pool); 1898 } 1899 1900 module_init(dm_crypt_init); 1901 module_exit(dm_crypt_exit); 1902 1903 MODULE_AUTHOR("Christophe Saout <christophe@saout.de>"); 1904 MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption"); 1905 MODULE_LICENSE("GPL"); 1906