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 <asm/atomic.h> 22 #include <linux/scatterlist.h> 23 #include <asm/page.h> 24 #include <asm/unaligned.h> 25 26 #include <linux/device-mapper.h> 27 28 #define DM_MSG_PREFIX "crypt" 29 #define MESG_STR(x) x, sizeof(x) 30 31 /* 32 * context holding the current state of a multi-part conversion 33 */ 34 struct convert_context { 35 struct completion restart; 36 struct bio *bio_in; 37 struct bio *bio_out; 38 unsigned int offset_in; 39 unsigned int offset_out; 40 unsigned int idx_in; 41 unsigned int idx_out; 42 sector_t sector; 43 atomic_t pending; 44 }; 45 46 /* 47 * per bio private data 48 */ 49 struct dm_crypt_io { 50 struct dm_target *target; 51 struct bio *base_bio; 52 struct work_struct work; 53 54 struct convert_context ctx; 55 56 atomic_t pending; 57 int error; 58 sector_t sector; 59 struct dm_crypt_io *base_io; 60 }; 61 62 struct dm_crypt_request { 63 struct convert_context *ctx; 64 struct scatterlist sg_in; 65 struct scatterlist sg_out; 66 }; 67 68 struct crypt_config; 69 70 struct crypt_iv_operations { 71 int (*ctr)(struct crypt_config *cc, struct dm_target *ti, 72 const char *opts); 73 void (*dtr)(struct crypt_config *cc); 74 int (*init)(struct crypt_config *cc); 75 int (*wipe)(struct crypt_config *cc); 76 int (*generator)(struct crypt_config *cc, u8 *iv, sector_t sector); 77 }; 78 79 struct iv_essiv_private { 80 struct crypto_cipher *tfm; 81 struct crypto_hash *hash_tfm; 82 u8 *salt; 83 }; 84 85 struct iv_benbi_private { 86 int shift; 87 }; 88 89 /* 90 * Crypt: maps a linear range of a block device 91 * and encrypts / decrypts at the same time. 92 */ 93 enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID }; 94 struct crypt_config { 95 struct dm_dev *dev; 96 sector_t start; 97 98 /* 99 * pool for per bio private data, crypto requests and 100 * encryption requeusts/buffer pages 101 */ 102 mempool_t *io_pool; 103 mempool_t *req_pool; 104 mempool_t *page_pool; 105 struct bio_set *bs; 106 107 struct workqueue_struct *io_queue; 108 struct workqueue_struct *crypt_queue; 109 110 /* 111 * crypto related data 112 */ 113 struct crypt_iv_operations *iv_gen_ops; 114 char *iv_mode; 115 union { 116 struct iv_essiv_private essiv; 117 struct iv_benbi_private benbi; 118 } iv_gen_private; 119 sector_t iv_offset; 120 unsigned int iv_size; 121 122 /* 123 * Layout of each crypto request: 124 * 125 * struct ablkcipher_request 126 * context 127 * padding 128 * struct dm_crypt_request 129 * padding 130 * IV 131 * 132 * The padding is added so that dm_crypt_request and the IV are 133 * correctly aligned. 134 */ 135 unsigned int dmreq_start; 136 struct ablkcipher_request *req; 137 138 char cipher[CRYPTO_MAX_ALG_NAME]; 139 char chainmode[CRYPTO_MAX_ALG_NAME]; 140 struct crypto_ablkcipher *tfm; 141 unsigned long flags; 142 unsigned int key_size; 143 u8 key[0]; 144 }; 145 146 #define MIN_IOS 16 147 #define MIN_POOL_PAGES 32 148 #define MIN_BIO_PAGES 8 149 150 static struct kmem_cache *_crypt_io_pool; 151 152 static void clone_init(struct dm_crypt_io *, struct bio *); 153 static void kcryptd_queue_crypt(struct dm_crypt_io *io); 154 155 /* 156 * Different IV generation algorithms: 157 * 158 * plain: the initial vector is the 32-bit little-endian version of the sector 159 * number, padded with zeros if necessary. 160 * 161 * plain64: the initial vector is the 64-bit little-endian version of the sector 162 * number, padded with zeros if necessary. 163 * 164 * essiv: "encrypted sector|salt initial vector", the sector number is 165 * encrypted with the bulk cipher using a salt as key. The salt 166 * should be derived from the bulk cipher's key via hashing. 167 * 168 * benbi: the 64-bit "big-endian 'narrow block'-count", starting at 1 169 * (needed for LRW-32-AES and possible other narrow block modes) 170 * 171 * null: the initial vector is always zero. Provides compatibility with 172 * obsolete loop_fish2 devices. Do not use for new devices. 173 * 174 * plumb: unimplemented, see: 175 * http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454 176 */ 177 178 static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv, sector_t sector) 179 { 180 memset(iv, 0, cc->iv_size); 181 *(u32 *)iv = cpu_to_le32(sector & 0xffffffff); 182 183 return 0; 184 } 185 186 static int crypt_iv_plain64_gen(struct crypt_config *cc, u8 *iv, 187 sector_t sector) 188 { 189 memset(iv, 0, cc->iv_size); 190 *(u64 *)iv = cpu_to_le64(sector); 191 192 return 0; 193 } 194 195 /* Initialise ESSIV - compute salt but no local memory allocations */ 196 static int crypt_iv_essiv_init(struct crypt_config *cc) 197 { 198 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv; 199 struct hash_desc desc; 200 struct scatterlist sg; 201 int err; 202 203 sg_init_one(&sg, cc->key, cc->key_size); 204 desc.tfm = essiv->hash_tfm; 205 desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; 206 207 err = crypto_hash_digest(&desc, &sg, cc->key_size, essiv->salt); 208 if (err) 209 return err; 210 211 return crypto_cipher_setkey(essiv->tfm, essiv->salt, 212 crypto_hash_digestsize(essiv->hash_tfm)); 213 } 214 215 /* Wipe salt and reset key derived from volume key */ 216 static int crypt_iv_essiv_wipe(struct crypt_config *cc) 217 { 218 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv; 219 unsigned salt_size = crypto_hash_digestsize(essiv->hash_tfm); 220 221 memset(essiv->salt, 0, salt_size); 222 223 return crypto_cipher_setkey(essiv->tfm, essiv->salt, salt_size); 224 } 225 226 static void crypt_iv_essiv_dtr(struct crypt_config *cc) 227 { 228 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv; 229 230 crypto_free_cipher(essiv->tfm); 231 essiv->tfm = NULL; 232 233 crypto_free_hash(essiv->hash_tfm); 234 essiv->hash_tfm = NULL; 235 236 kzfree(essiv->salt); 237 essiv->salt = NULL; 238 } 239 240 static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti, 241 const char *opts) 242 { 243 struct crypto_cipher *essiv_tfm = NULL; 244 struct crypto_hash *hash_tfm = NULL; 245 u8 *salt = NULL; 246 int err; 247 248 if (!opts) { 249 ti->error = "Digest algorithm missing for ESSIV mode"; 250 return -EINVAL; 251 } 252 253 /* Allocate hash algorithm */ 254 hash_tfm = crypto_alloc_hash(opts, 0, CRYPTO_ALG_ASYNC); 255 if (IS_ERR(hash_tfm)) { 256 ti->error = "Error initializing ESSIV hash"; 257 err = PTR_ERR(hash_tfm); 258 goto bad; 259 } 260 261 salt = kzalloc(crypto_hash_digestsize(hash_tfm), GFP_KERNEL); 262 if (!salt) { 263 ti->error = "Error kmallocing salt storage in ESSIV"; 264 err = -ENOMEM; 265 goto bad; 266 } 267 268 /* Allocate essiv_tfm */ 269 essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC); 270 if (IS_ERR(essiv_tfm)) { 271 ti->error = "Error allocating crypto tfm for ESSIV"; 272 err = PTR_ERR(essiv_tfm); 273 goto bad; 274 } 275 if (crypto_cipher_blocksize(essiv_tfm) != 276 crypto_ablkcipher_ivsize(cc->tfm)) { 277 ti->error = "Block size of ESSIV cipher does " 278 "not match IV size of block cipher"; 279 err = -EINVAL; 280 goto bad; 281 } 282 283 cc->iv_gen_private.essiv.salt = salt; 284 cc->iv_gen_private.essiv.tfm = essiv_tfm; 285 cc->iv_gen_private.essiv.hash_tfm = hash_tfm; 286 287 return 0; 288 289 bad: 290 if (essiv_tfm && !IS_ERR(essiv_tfm)) 291 crypto_free_cipher(essiv_tfm); 292 if (hash_tfm && !IS_ERR(hash_tfm)) 293 crypto_free_hash(hash_tfm); 294 kfree(salt); 295 return err; 296 } 297 298 static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv, sector_t sector) 299 { 300 memset(iv, 0, cc->iv_size); 301 *(u64 *)iv = cpu_to_le64(sector); 302 crypto_cipher_encrypt_one(cc->iv_gen_private.essiv.tfm, iv, iv); 303 return 0; 304 } 305 306 static int crypt_iv_benbi_ctr(struct crypt_config *cc, struct dm_target *ti, 307 const char *opts) 308 { 309 unsigned bs = crypto_ablkcipher_blocksize(cc->tfm); 310 int log = ilog2(bs); 311 312 /* we need to calculate how far we must shift the sector count 313 * to get the cipher block count, we use this shift in _gen */ 314 315 if (1 << log != bs) { 316 ti->error = "cypher blocksize is not a power of 2"; 317 return -EINVAL; 318 } 319 320 if (log > 9) { 321 ti->error = "cypher blocksize is > 512"; 322 return -EINVAL; 323 } 324 325 cc->iv_gen_private.benbi.shift = 9 - log; 326 327 return 0; 328 } 329 330 static void crypt_iv_benbi_dtr(struct crypt_config *cc) 331 { 332 } 333 334 static int crypt_iv_benbi_gen(struct crypt_config *cc, u8 *iv, sector_t sector) 335 { 336 __be64 val; 337 338 memset(iv, 0, cc->iv_size - sizeof(u64)); /* rest is cleared below */ 339 340 val = cpu_to_be64(((u64)sector << cc->iv_gen_private.benbi.shift) + 1); 341 put_unaligned(val, (__be64 *)(iv + cc->iv_size - sizeof(u64))); 342 343 return 0; 344 } 345 346 static int crypt_iv_null_gen(struct crypt_config *cc, u8 *iv, sector_t sector) 347 { 348 memset(iv, 0, cc->iv_size); 349 350 return 0; 351 } 352 353 static struct crypt_iv_operations crypt_iv_plain_ops = { 354 .generator = crypt_iv_plain_gen 355 }; 356 357 static struct crypt_iv_operations crypt_iv_plain64_ops = { 358 .generator = crypt_iv_plain64_gen 359 }; 360 361 static struct crypt_iv_operations crypt_iv_essiv_ops = { 362 .ctr = crypt_iv_essiv_ctr, 363 .dtr = crypt_iv_essiv_dtr, 364 .init = crypt_iv_essiv_init, 365 .wipe = crypt_iv_essiv_wipe, 366 .generator = crypt_iv_essiv_gen 367 }; 368 369 static struct crypt_iv_operations crypt_iv_benbi_ops = { 370 .ctr = crypt_iv_benbi_ctr, 371 .dtr = crypt_iv_benbi_dtr, 372 .generator = crypt_iv_benbi_gen 373 }; 374 375 static struct crypt_iv_operations crypt_iv_null_ops = { 376 .generator = crypt_iv_null_gen 377 }; 378 379 static void crypt_convert_init(struct crypt_config *cc, 380 struct convert_context *ctx, 381 struct bio *bio_out, struct bio *bio_in, 382 sector_t sector) 383 { 384 ctx->bio_in = bio_in; 385 ctx->bio_out = bio_out; 386 ctx->offset_in = 0; 387 ctx->offset_out = 0; 388 ctx->idx_in = bio_in ? bio_in->bi_idx : 0; 389 ctx->idx_out = bio_out ? bio_out->bi_idx : 0; 390 ctx->sector = sector + cc->iv_offset; 391 init_completion(&ctx->restart); 392 } 393 394 static struct dm_crypt_request *dmreq_of_req(struct crypt_config *cc, 395 struct ablkcipher_request *req) 396 { 397 return (struct dm_crypt_request *)((char *)req + cc->dmreq_start); 398 } 399 400 static struct ablkcipher_request *req_of_dmreq(struct crypt_config *cc, 401 struct dm_crypt_request *dmreq) 402 { 403 return (struct ablkcipher_request *)((char *)dmreq - cc->dmreq_start); 404 } 405 406 static int crypt_convert_block(struct crypt_config *cc, 407 struct convert_context *ctx, 408 struct ablkcipher_request *req) 409 { 410 struct bio_vec *bv_in = bio_iovec_idx(ctx->bio_in, ctx->idx_in); 411 struct bio_vec *bv_out = bio_iovec_idx(ctx->bio_out, ctx->idx_out); 412 struct dm_crypt_request *dmreq; 413 u8 *iv; 414 int r = 0; 415 416 dmreq = dmreq_of_req(cc, req); 417 iv = (u8 *)ALIGN((unsigned long)(dmreq + 1), 418 crypto_ablkcipher_alignmask(cc->tfm) + 1); 419 420 dmreq->ctx = ctx; 421 sg_init_table(&dmreq->sg_in, 1); 422 sg_set_page(&dmreq->sg_in, bv_in->bv_page, 1 << SECTOR_SHIFT, 423 bv_in->bv_offset + ctx->offset_in); 424 425 sg_init_table(&dmreq->sg_out, 1); 426 sg_set_page(&dmreq->sg_out, bv_out->bv_page, 1 << SECTOR_SHIFT, 427 bv_out->bv_offset + ctx->offset_out); 428 429 ctx->offset_in += 1 << SECTOR_SHIFT; 430 if (ctx->offset_in >= bv_in->bv_len) { 431 ctx->offset_in = 0; 432 ctx->idx_in++; 433 } 434 435 ctx->offset_out += 1 << SECTOR_SHIFT; 436 if (ctx->offset_out >= bv_out->bv_len) { 437 ctx->offset_out = 0; 438 ctx->idx_out++; 439 } 440 441 if (cc->iv_gen_ops) { 442 r = cc->iv_gen_ops->generator(cc, iv, ctx->sector); 443 if (r < 0) 444 return r; 445 } 446 447 ablkcipher_request_set_crypt(req, &dmreq->sg_in, &dmreq->sg_out, 448 1 << SECTOR_SHIFT, iv); 449 450 if (bio_data_dir(ctx->bio_in) == WRITE) 451 r = crypto_ablkcipher_encrypt(req); 452 else 453 r = crypto_ablkcipher_decrypt(req); 454 455 return r; 456 } 457 458 static void kcryptd_async_done(struct crypto_async_request *async_req, 459 int error); 460 static void crypt_alloc_req(struct crypt_config *cc, 461 struct convert_context *ctx) 462 { 463 if (!cc->req) 464 cc->req = mempool_alloc(cc->req_pool, GFP_NOIO); 465 ablkcipher_request_set_tfm(cc->req, cc->tfm); 466 ablkcipher_request_set_callback(cc->req, CRYPTO_TFM_REQ_MAY_BACKLOG | 467 CRYPTO_TFM_REQ_MAY_SLEEP, 468 kcryptd_async_done, 469 dmreq_of_req(cc, cc->req)); 470 } 471 472 /* 473 * Encrypt / decrypt data from one bio to another one (can be the same one) 474 */ 475 static int crypt_convert(struct crypt_config *cc, 476 struct convert_context *ctx) 477 { 478 int r; 479 480 atomic_set(&ctx->pending, 1); 481 482 while(ctx->idx_in < ctx->bio_in->bi_vcnt && 483 ctx->idx_out < ctx->bio_out->bi_vcnt) { 484 485 crypt_alloc_req(cc, ctx); 486 487 atomic_inc(&ctx->pending); 488 489 r = crypt_convert_block(cc, ctx, cc->req); 490 491 switch (r) { 492 /* async */ 493 case -EBUSY: 494 wait_for_completion(&ctx->restart); 495 INIT_COMPLETION(ctx->restart); 496 /* fall through*/ 497 case -EINPROGRESS: 498 cc->req = NULL; 499 ctx->sector++; 500 continue; 501 502 /* sync */ 503 case 0: 504 atomic_dec(&ctx->pending); 505 ctx->sector++; 506 cond_resched(); 507 continue; 508 509 /* error */ 510 default: 511 atomic_dec(&ctx->pending); 512 return r; 513 } 514 } 515 516 return 0; 517 } 518 519 static void dm_crypt_bio_destructor(struct bio *bio) 520 { 521 struct dm_crypt_io *io = bio->bi_private; 522 struct crypt_config *cc = io->target->private; 523 524 bio_free(bio, cc->bs); 525 } 526 527 /* 528 * Generate a new unfragmented bio with the given size 529 * This should never violate the device limitations 530 * May return a smaller bio when running out of pages, indicated by 531 * *out_of_pages set to 1. 532 */ 533 static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size, 534 unsigned *out_of_pages) 535 { 536 struct crypt_config *cc = io->target->private; 537 struct bio *clone; 538 unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; 539 gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM; 540 unsigned i, len; 541 struct page *page; 542 543 clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs); 544 if (!clone) 545 return NULL; 546 547 clone_init(io, clone); 548 *out_of_pages = 0; 549 550 for (i = 0; i < nr_iovecs; i++) { 551 page = mempool_alloc(cc->page_pool, gfp_mask); 552 if (!page) { 553 *out_of_pages = 1; 554 break; 555 } 556 557 /* 558 * if additional pages cannot be allocated without waiting, 559 * return a partially allocated bio, the caller will then try 560 * to allocate additional bios while submitting this partial bio 561 */ 562 if (i == (MIN_BIO_PAGES - 1)) 563 gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT; 564 565 len = (size > PAGE_SIZE) ? PAGE_SIZE : size; 566 567 if (!bio_add_page(clone, page, len, 0)) { 568 mempool_free(page, cc->page_pool); 569 break; 570 } 571 572 size -= len; 573 } 574 575 if (!clone->bi_size) { 576 bio_put(clone); 577 return NULL; 578 } 579 580 return clone; 581 } 582 583 static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone) 584 { 585 unsigned int i; 586 struct bio_vec *bv; 587 588 for (i = 0; i < clone->bi_vcnt; i++) { 589 bv = bio_iovec_idx(clone, i); 590 BUG_ON(!bv->bv_page); 591 mempool_free(bv->bv_page, cc->page_pool); 592 bv->bv_page = NULL; 593 } 594 } 595 596 static struct dm_crypt_io *crypt_io_alloc(struct dm_target *ti, 597 struct bio *bio, sector_t sector) 598 { 599 struct crypt_config *cc = ti->private; 600 struct dm_crypt_io *io; 601 602 io = mempool_alloc(cc->io_pool, GFP_NOIO); 603 io->target = ti; 604 io->base_bio = bio; 605 io->sector = sector; 606 io->error = 0; 607 io->base_io = NULL; 608 atomic_set(&io->pending, 0); 609 610 return io; 611 } 612 613 static void crypt_inc_pending(struct dm_crypt_io *io) 614 { 615 atomic_inc(&io->pending); 616 } 617 618 /* 619 * One of the bios was finished. Check for completion of 620 * the whole request and correctly clean up the buffer. 621 * If base_io is set, wait for the last fragment to complete. 622 */ 623 static void crypt_dec_pending(struct dm_crypt_io *io) 624 { 625 struct crypt_config *cc = io->target->private; 626 struct bio *base_bio = io->base_bio; 627 struct dm_crypt_io *base_io = io->base_io; 628 int error = io->error; 629 630 if (!atomic_dec_and_test(&io->pending)) 631 return; 632 633 mempool_free(io, cc->io_pool); 634 635 if (likely(!base_io)) 636 bio_endio(base_bio, error); 637 else { 638 if (error && !base_io->error) 639 base_io->error = error; 640 crypt_dec_pending(base_io); 641 } 642 } 643 644 /* 645 * kcryptd/kcryptd_io: 646 * 647 * Needed because it would be very unwise to do decryption in an 648 * interrupt context. 649 * 650 * kcryptd performs the actual encryption or decryption. 651 * 652 * kcryptd_io performs the IO submission. 653 * 654 * They must be separated as otherwise the final stages could be 655 * starved by new requests which can block in the first stages due 656 * to memory allocation. 657 */ 658 static void crypt_endio(struct bio *clone, int error) 659 { 660 struct dm_crypt_io *io = clone->bi_private; 661 struct crypt_config *cc = io->target->private; 662 unsigned rw = bio_data_dir(clone); 663 664 if (unlikely(!bio_flagged(clone, BIO_UPTODATE) && !error)) 665 error = -EIO; 666 667 /* 668 * free the processed pages 669 */ 670 if (rw == WRITE) 671 crypt_free_buffer_pages(cc, clone); 672 673 bio_put(clone); 674 675 if (rw == READ && !error) { 676 kcryptd_queue_crypt(io); 677 return; 678 } 679 680 if (unlikely(error)) 681 io->error = error; 682 683 crypt_dec_pending(io); 684 } 685 686 static void clone_init(struct dm_crypt_io *io, struct bio *clone) 687 { 688 struct crypt_config *cc = io->target->private; 689 690 clone->bi_private = io; 691 clone->bi_end_io = crypt_endio; 692 clone->bi_bdev = cc->dev->bdev; 693 clone->bi_rw = io->base_bio->bi_rw; 694 clone->bi_destructor = dm_crypt_bio_destructor; 695 } 696 697 static void kcryptd_io_read(struct dm_crypt_io *io) 698 { 699 struct crypt_config *cc = io->target->private; 700 struct bio *base_bio = io->base_bio; 701 struct bio *clone; 702 703 crypt_inc_pending(io); 704 705 /* 706 * The block layer might modify the bvec array, so always 707 * copy the required bvecs because we need the original 708 * one in order to decrypt the whole bio data *afterwards*. 709 */ 710 clone = bio_alloc_bioset(GFP_NOIO, bio_segments(base_bio), cc->bs); 711 if (unlikely(!clone)) { 712 io->error = -ENOMEM; 713 crypt_dec_pending(io); 714 return; 715 } 716 717 clone_init(io, clone); 718 clone->bi_idx = 0; 719 clone->bi_vcnt = bio_segments(base_bio); 720 clone->bi_size = base_bio->bi_size; 721 clone->bi_sector = cc->start + io->sector; 722 memcpy(clone->bi_io_vec, bio_iovec(base_bio), 723 sizeof(struct bio_vec) * clone->bi_vcnt); 724 725 generic_make_request(clone); 726 } 727 728 static void kcryptd_io_write(struct dm_crypt_io *io) 729 { 730 struct bio *clone = io->ctx.bio_out; 731 generic_make_request(clone); 732 } 733 734 static void kcryptd_io(struct work_struct *work) 735 { 736 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work); 737 738 if (bio_data_dir(io->base_bio) == READ) 739 kcryptd_io_read(io); 740 else 741 kcryptd_io_write(io); 742 } 743 744 static void kcryptd_queue_io(struct dm_crypt_io *io) 745 { 746 struct crypt_config *cc = io->target->private; 747 748 INIT_WORK(&io->work, kcryptd_io); 749 queue_work(cc->io_queue, &io->work); 750 } 751 752 static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io, 753 int error, int async) 754 { 755 struct bio *clone = io->ctx.bio_out; 756 struct crypt_config *cc = io->target->private; 757 758 if (unlikely(error < 0)) { 759 crypt_free_buffer_pages(cc, clone); 760 bio_put(clone); 761 io->error = -EIO; 762 crypt_dec_pending(io); 763 return; 764 } 765 766 /* crypt_convert should have filled the clone bio */ 767 BUG_ON(io->ctx.idx_out < clone->bi_vcnt); 768 769 clone->bi_sector = cc->start + io->sector; 770 771 if (async) 772 kcryptd_queue_io(io); 773 else 774 generic_make_request(clone); 775 } 776 777 static void kcryptd_crypt_write_convert(struct dm_crypt_io *io) 778 { 779 struct crypt_config *cc = io->target->private; 780 struct bio *clone; 781 struct dm_crypt_io *new_io; 782 int crypt_finished; 783 unsigned out_of_pages = 0; 784 unsigned remaining = io->base_bio->bi_size; 785 sector_t sector = io->sector; 786 int r; 787 788 /* 789 * Prevent io from disappearing until this function completes. 790 */ 791 crypt_inc_pending(io); 792 crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, sector); 793 794 /* 795 * The allocated buffers can be smaller than the whole bio, 796 * so repeat the whole process until all the data can be handled. 797 */ 798 while (remaining) { 799 clone = crypt_alloc_buffer(io, remaining, &out_of_pages); 800 if (unlikely(!clone)) { 801 io->error = -ENOMEM; 802 break; 803 } 804 805 io->ctx.bio_out = clone; 806 io->ctx.idx_out = 0; 807 808 remaining -= clone->bi_size; 809 sector += bio_sectors(clone); 810 811 crypt_inc_pending(io); 812 r = crypt_convert(cc, &io->ctx); 813 crypt_finished = atomic_dec_and_test(&io->ctx.pending); 814 815 /* Encryption was already finished, submit io now */ 816 if (crypt_finished) { 817 kcryptd_crypt_write_io_submit(io, r, 0); 818 819 /* 820 * If there was an error, do not try next fragments. 821 * For async, error is processed in async handler. 822 */ 823 if (unlikely(r < 0)) 824 break; 825 826 io->sector = sector; 827 } 828 829 /* 830 * Out of memory -> run queues 831 * But don't wait if split was due to the io size restriction 832 */ 833 if (unlikely(out_of_pages)) 834 congestion_wait(BLK_RW_ASYNC, HZ/100); 835 836 /* 837 * With async crypto it is unsafe to share the crypto context 838 * between fragments, so switch to a new dm_crypt_io structure. 839 */ 840 if (unlikely(!crypt_finished && remaining)) { 841 new_io = crypt_io_alloc(io->target, io->base_bio, 842 sector); 843 crypt_inc_pending(new_io); 844 crypt_convert_init(cc, &new_io->ctx, NULL, 845 io->base_bio, sector); 846 new_io->ctx.idx_in = io->ctx.idx_in; 847 new_io->ctx.offset_in = io->ctx.offset_in; 848 849 /* 850 * Fragments after the first use the base_io 851 * pending count. 852 */ 853 if (!io->base_io) 854 new_io->base_io = io; 855 else { 856 new_io->base_io = io->base_io; 857 crypt_inc_pending(io->base_io); 858 crypt_dec_pending(io); 859 } 860 861 io = new_io; 862 } 863 } 864 865 crypt_dec_pending(io); 866 } 867 868 static void kcryptd_crypt_read_done(struct dm_crypt_io *io, int error) 869 { 870 if (unlikely(error < 0)) 871 io->error = -EIO; 872 873 crypt_dec_pending(io); 874 } 875 876 static void kcryptd_crypt_read_convert(struct dm_crypt_io *io) 877 { 878 struct crypt_config *cc = io->target->private; 879 int r = 0; 880 881 crypt_inc_pending(io); 882 883 crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio, 884 io->sector); 885 886 r = crypt_convert(cc, &io->ctx); 887 888 if (atomic_dec_and_test(&io->ctx.pending)) 889 kcryptd_crypt_read_done(io, r); 890 891 crypt_dec_pending(io); 892 } 893 894 static void kcryptd_async_done(struct crypto_async_request *async_req, 895 int error) 896 { 897 struct dm_crypt_request *dmreq = async_req->data; 898 struct convert_context *ctx = dmreq->ctx; 899 struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx); 900 struct crypt_config *cc = io->target->private; 901 902 if (error == -EINPROGRESS) { 903 complete(&ctx->restart); 904 return; 905 } 906 907 mempool_free(req_of_dmreq(cc, dmreq), cc->req_pool); 908 909 if (!atomic_dec_and_test(&ctx->pending)) 910 return; 911 912 if (bio_data_dir(io->base_bio) == READ) 913 kcryptd_crypt_read_done(io, error); 914 else 915 kcryptd_crypt_write_io_submit(io, error, 1); 916 } 917 918 static void kcryptd_crypt(struct work_struct *work) 919 { 920 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work); 921 922 if (bio_data_dir(io->base_bio) == READ) 923 kcryptd_crypt_read_convert(io); 924 else 925 kcryptd_crypt_write_convert(io); 926 } 927 928 static void kcryptd_queue_crypt(struct dm_crypt_io *io) 929 { 930 struct crypt_config *cc = io->target->private; 931 932 INIT_WORK(&io->work, kcryptd_crypt); 933 queue_work(cc->crypt_queue, &io->work); 934 } 935 936 /* 937 * Decode key from its hex representation 938 */ 939 static int crypt_decode_key(u8 *key, char *hex, unsigned int size) 940 { 941 char buffer[3]; 942 char *endp; 943 unsigned int i; 944 945 buffer[2] = '\0'; 946 947 for (i = 0; i < size; i++) { 948 buffer[0] = *hex++; 949 buffer[1] = *hex++; 950 951 key[i] = (u8)simple_strtoul(buffer, &endp, 16); 952 953 if (endp != &buffer[2]) 954 return -EINVAL; 955 } 956 957 if (*hex != '\0') 958 return -EINVAL; 959 960 return 0; 961 } 962 963 /* 964 * Encode key into its hex representation 965 */ 966 static void crypt_encode_key(char *hex, u8 *key, unsigned int size) 967 { 968 unsigned int i; 969 970 for (i = 0; i < size; i++) { 971 sprintf(hex, "%02x", *key); 972 hex += 2; 973 key++; 974 } 975 } 976 977 static int crypt_set_key(struct crypt_config *cc, char *key) 978 { 979 unsigned key_size = strlen(key) >> 1; 980 981 if (cc->key_size && cc->key_size != key_size) 982 return -EINVAL; 983 984 cc->key_size = key_size; /* initial settings */ 985 986 if ((!key_size && strcmp(key, "-")) || 987 (key_size && crypt_decode_key(cc->key, key, key_size) < 0)) 988 return -EINVAL; 989 990 set_bit(DM_CRYPT_KEY_VALID, &cc->flags); 991 992 return crypto_ablkcipher_setkey(cc->tfm, cc->key, cc->key_size); 993 } 994 995 static int crypt_wipe_key(struct crypt_config *cc) 996 { 997 clear_bit(DM_CRYPT_KEY_VALID, &cc->flags); 998 memset(&cc->key, 0, cc->key_size * sizeof(u8)); 999 return crypto_ablkcipher_setkey(cc->tfm, cc->key, cc->key_size); 1000 } 1001 1002 /* 1003 * Construct an encryption mapping: 1004 * <cipher> <key> <iv_offset> <dev_path> <start> 1005 */ 1006 static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv) 1007 { 1008 struct crypt_config *cc; 1009 struct crypto_ablkcipher *tfm; 1010 char *tmp; 1011 char *cipher; 1012 char *chainmode; 1013 char *ivmode; 1014 char *ivopts; 1015 unsigned int key_size; 1016 unsigned long long tmpll; 1017 1018 if (argc != 5) { 1019 ti->error = "Not enough arguments"; 1020 return -EINVAL; 1021 } 1022 1023 tmp = argv[0]; 1024 cipher = strsep(&tmp, "-"); 1025 chainmode = strsep(&tmp, "-"); 1026 ivopts = strsep(&tmp, "-"); 1027 ivmode = strsep(&ivopts, ":"); 1028 1029 if (tmp) 1030 DMWARN("Unexpected additional cipher options"); 1031 1032 key_size = strlen(argv[1]) >> 1; 1033 1034 cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL); 1035 if (cc == NULL) { 1036 ti->error = 1037 "Cannot allocate transparent encryption context"; 1038 return -ENOMEM; 1039 } 1040 1041 /* Compatibility mode for old dm-crypt cipher strings */ 1042 if (!chainmode || (strcmp(chainmode, "plain") == 0 && !ivmode)) { 1043 chainmode = "cbc"; 1044 ivmode = "plain"; 1045 } 1046 1047 if (strcmp(chainmode, "ecb") && !ivmode) { 1048 ti->error = "This chaining mode requires an IV mechanism"; 1049 goto bad_cipher; 1050 } 1051 1052 if (snprintf(cc->cipher, CRYPTO_MAX_ALG_NAME, "%s(%s)", 1053 chainmode, cipher) >= CRYPTO_MAX_ALG_NAME) { 1054 ti->error = "Chain mode + cipher name is too long"; 1055 goto bad_cipher; 1056 } 1057 1058 tfm = crypto_alloc_ablkcipher(cc->cipher, 0, 0); 1059 if (IS_ERR(tfm)) { 1060 ti->error = "Error allocating crypto tfm"; 1061 goto bad_cipher; 1062 } 1063 1064 strcpy(cc->cipher, cipher); 1065 strcpy(cc->chainmode, chainmode); 1066 cc->tfm = tfm; 1067 1068 if (crypt_set_key(cc, argv[1]) < 0) { 1069 ti->error = "Error decoding and setting key"; 1070 goto bad_ivmode; 1071 } 1072 1073 /* 1074 * Choose ivmode. Valid modes: "plain", "essiv:<esshash>", "benbi". 1075 * See comments at iv code 1076 */ 1077 1078 if (ivmode == NULL) 1079 cc->iv_gen_ops = NULL; 1080 else if (strcmp(ivmode, "plain") == 0) 1081 cc->iv_gen_ops = &crypt_iv_plain_ops; 1082 else if (strcmp(ivmode, "plain64") == 0) 1083 cc->iv_gen_ops = &crypt_iv_plain64_ops; 1084 else if (strcmp(ivmode, "essiv") == 0) 1085 cc->iv_gen_ops = &crypt_iv_essiv_ops; 1086 else if (strcmp(ivmode, "benbi") == 0) 1087 cc->iv_gen_ops = &crypt_iv_benbi_ops; 1088 else if (strcmp(ivmode, "null") == 0) 1089 cc->iv_gen_ops = &crypt_iv_null_ops; 1090 else { 1091 ti->error = "Invalid IV mode"; 1092 goto bad_ivmode; 1093 } 1094 1095 if (cc->iv_gen_ops && cc->iv_gen_ops->ctr && 1096 cc->iv_gen_ops->ctr(cc, ti, ivopts) < 0) 1097 goto bad_ivmode; 1098 1099 if (cc->iv_gen_ops && cc->iv_gen_ops->init && 1100 cc->iv_gen_ops->init(cc) < 0) { 1101 ti->error = "Error initialising IV"; 1102 goto bad_slab_pool; 1103 } 1104 1105 cc->iv_size = crypto_ablkcipher_ivsize(tfm); 1106 if (cc->iv_size) 1107 /* at least a 64 bit sector number should fit in our buffer */ 1108 cc->iv_size = max(cc->iv_size, 1109 (unsigned int)(sizeof(u64) / sizeof(u8))); 1110 else { 1111 if (cc->iv_gen_ops) { 1112 DMWARN("Selected cipher does not support IVs"); 1113 if (cc->iv_gen_ops->dtr) 1114 cc->iv_gen_ops->dtr(cc); 1115 cc->iv_gen_ops = NULL; 1116 } 1117 } 1118 1119 cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool); 1120 if (!cc->io_pool) { 1121 ti->error = "Cannot allocate crypt io mempool"; 1122 goto bad_slab_pool; 1123 } 1124 1125 cc->dmreq_start = sizeof(struct ablkcipher_request); 1126 cc->dmreq_start += crypto_ablkcipher_reqsize(tfm); 1127 cc->dmreq_start = ALIGN(cc->dmreq_start, crypto_tfm_ctx_alignment()); 1128 cc->dmreq_start += crypto_ablkcipher_alignmask(tfm) & 1129 ~(crypto_tfm_ctx_alignment() - 1); 1130 1131 cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start + 1132 sizeof(struct dm_crypt_request) + cc->iv_size); 1133 if (!cc->req_pool) { 1134 ti->error = "Cannot allocate crypt request mempool"; 1135 goto bad_req_pool; 1136 } 1137 cc->req = NULL; 1138 1139 cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0); 1140 if (!cc->page_pool) { 1141 ti->error = "Cannot allocate page mempool"; 1142 goto bad_page_pool; 1143 } 1144 1145 cc->bs = bioset_create(MIN_IOS, 0); 1146 if (!cc->bs) { 1147 ti->error = "Cannot allocate crypt bioset"; 1148 goto bad_bs; 1149 } 1150 1151 if (sscanf(argv[2], "%llu", &tmpll) != 1) { 1152 ti->error = "Invalid iv_offset sector"; 1153 goto bad_device; 1154 } 1155 cc->iv_offset = tmpll; 1156 1157 if (sscanf(argv[4], "%llu", &tmpll) != 1) { 1158 ti->error = "Invalid device sector"; 1159 goto bad_device; 1160 } 1161 cc->start = tmpll; 1162 1163 if (dm_get_device(ti, argv[3], cc->start, ti->len, 1164 dm_table_get_mode(ti->table), &cc->dev)) { 1165 ti->error = "Device lookup failed"; 1166 goto bad_device; 1167 } 1168 1169 if (ivmode && cc->iv_gen_ops) { 1170 if (ivopts) 1171 *(ivopts - 1) = ':'; 1172 cc->iv_mode = kmalloc(strlen(ivmode) + 1, GFP_KERNEL); 1173 if (!cc->iv_mode) { 1174 ti->error = "Error kmallocing iv_mode string"; 1175 goto bad_ivmode_string; 1176 } 1177 strcpy(cc->iv_mode, ivmode); 1178 } else 1179 cc->iv_mode = NULL; 1180 1181 cc->io_queue = create_singlethread_workqueue("kcryptd_io"); 1182 if (!cc->io_queue) { 1183 ti->error = "Couldn't create kcryptd io queue"; 1184 goto bad_io_queue; 1185 } 1186 1187 cc->crypt_queue = create_singlethread_workqueue("kcryptd"); 1188 if (!cc->crypt_queue) { 1189 ti->error = "Couldn't create kcryptd queue"; 1190 goto bad_crypt_queue; 1191 } 1192 1193 ti->num_flush_requests = 1; 1194 ti->private = cc; 1195 return 0; 1196 1197 bad_crypt_queue: 1198 destroy_workqueue(cc->io_queue); 1199 bad_io_queue: 1200 kfree(cc->iv_mode); 1201 bad_ivmode_string: 1202 dm_put_device(ti, cc->dev); 1203 bad_device: 1204 bioset_free(cc->bs); 1205 bad_bs: 1206 mempool_destroy(cc->page_pool); 1207 bad_page_pool: 1208 mempool_destroy(cc->req_pool); 1209 bad_req_pool: 1210 mempool_destroy(cc->io_pool); 1211 bad_slab_pool: 1212 if (cc->iv_gen_ops && cc->iv_gen_ops->dtr) 1213 cc->iv_gen_ops->dtr(cc); 1214 bad_ivmode: 1215 crypto_free_ablkcipher(tfm); 1216 bad_cipher: 1217 /* Must zero key material before freeing */ 1218 kzfree(cc); 1219 return -EINVAL; 1220 } 1221 1222 static void crypt_dtr(struct dm_target *ti) 1223 { 1224 struct crypt_config *cc = (struct crypt_config *) ti->private; 1225 1226 destroy_workqueue(cc->io_queue); 1227 destroy_workqueue(cc->crypt_queue); 1228 1229 if (cc->req) 1230 mempool_free(cc->req, cc->req_pool); 1231 1232 bioset_free(cc->bs); 1233 mempool_destroy(cc->page_pool); 1234 mempool_destroy(cc->req_pool); 1235 mempool_destroy(cc->io_pool); 1236 1237 kfree(cc->iv_mode); 1238 if (cc->iv_gen_ops && cc->iv_gen_ops->dtr) 1239 cc->iv_gen_ops->dtr(cc); 1240 crypto_free_ablkcipher(cc->tfm); 1241 dm_put_device(ti, cc->dev); 1242 1243 /* Must zero key material before freeing */ 1244 kzfree(cc); 1245 } 1246 1247 static int crypt_map(struct dm_target *ti, struct bio *bio, 1248 union map_info *map_context) 1249 { 1250 struct dm_crypt_io *io; 1251 struct crypt_config *cc; 1252 1253 if (unlikely(bio_empty_barrier(bio))) { 1254 cc = ti->private; 1255 bio->bi_bdev = cc->dev->bdev; 1256 return DM_MAPIO_REMAPPED; 1257 } 1258 1259 io = crypt_io_alloc(ti, bio, bio->bi_sector - ti->begin); 1260 1261 if (bio_data_dir(io->base_bio) == READ) 1262 kcryptd_queue_io(io); 1263 else 1264 kcryptd_queue_crypt(io); 1265 1266 return DM_MAPIO_SUBMITTED; 1267 } 1268 1269 static int crypt_status(struct dm_target *ti, status_type_t type, 1270 char *result, unsigned int maxlen) 1271 { 1272 struct crypt_config *cc = (struct crypt_config *) ti->private; 1273 unsigned int sz = 0; 1274 1275 switch (type) { 1276 case STATUSTYPE_INFO: 1277 result[0] = '\0'; 1278 break; 1279 1280 case STATUSTYPE_TABLE: 1281 if (cc->iv_mode) 1282 DMEMIT("%s-%s-%s ", cc->cipher, cc->chainmode, 1283 cc->iv_mode); 1284 else 1285 DMEMIT("%s-%s ", cc->cipher, cc->chainmode); 1286 1287 if (cc->key_size > 0) { 1288 if ((maxlen - sz) < ((cc->key_size << 1) + 1)) 1289 return -ENOMEM; 1290 1291 crypt_encode_key(result + sz, cc->key, cc->key_size); 1292 sz += cc->key_size << 1; 1293 } else { 1294 if (sz >= maxlen) 1295 return -ENOMEM; 1296 result[sz++] = '-'; 1297 } 1298 1299 DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset, 1300 cc->dev->name, (unsigned long long)cc->start); 1301 break; 1302 } 1303 return 0; 1304 } 1305 1306 static void crypt_postsuspend(struct dm_target *ti) 1307 { 1308 struct crypt_config *cc = ti->private; 1309 1310 set_bit(DM_CRYPT_SUSPENDED, &cc->flags); 1311 } 1312 1313 static int crypt_preresume(struct dm_target *ti) 1314 { 1315 struct crypt_config *cc = ti->private; 1316 1317 if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) { 1318 DMERR("aborting resume - crypt key is not set."); 1319 return -EAGAIN; 1320 } 1321 1322 return 0; 1323 } 1324 1325 static void crypt_resume(struct dm_target *ti) 1326 { 1327 struct crypt_config *cc = ti->private; 1328 1329 clear_bit(DM_CRYPT_SUSPENDED, &cc->flags); 1330 } 1331 1332 /* Message interface 1333 * key set <key> 1334 * key wipe 1335 */ 1336 static int crypt_message(struct dm_target *ti, unsigned argc, char **argv) 1337 { 1338 struct crypt_config *cc = ti->private; 1339 int ret = -EINVAL; 1340 1341 if (argc < 2) 1342 goto error; 1343 1344 if (!strnicmp(argv[0], MESG_STR("key"))) { 1345 if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) { 1346 DMWARN("not suspended during key manipulation."); 1347 return -EINVAL; 1348 } 1349 if (argc == 3 && !strnicmp(argv[1], MESG_STR("set"))) { 1350 ret = crypt_set_key(cc, argv[2]); 1351 if (ret) 1352 return ret; 1353 if (cc->iv_gen_ops && cc->iv_gen_ops->init) 1354 ret = cc->iv_gen_ops->init(cc); 1355 return ret; 1356 } 1357 if (argc == 2 && !strnicmp(argv[1], MESG_STR("wipe"))) { 1358 if (cc->iv_gen_ops && cc->iv_gen_ops->wipe) { 1359 ret = cc->iv_gen_ops->wipe(cc); 1360 if (ret) 1361 return ret; 1362 } 1363 return crypt_wipe_key(cc); 1364 } 1365 } 1366 1367 error: 1368 DMWARN("unrecognised message received."); 1369 return -EINVAL; 1370 } 1371 1372 static int crypt_merge(struct dm_target *ti, struct bvec_merge_data *bvm, 1373 struct bio_vec *biovec, int max_size) 1374 { 1375 struct crypt_config *cc = ti->private; 1376 struct request_queue *q = bdev_get_queue(cc->dev->bdev); 1377 1378 if (!q->merge_bvec_fn) 1379 return max_size; 1380 1381 bvm->bi_bdev = cc->dev->bdev; 1382 bvm->bi_sector = cc->start + bvm->bi_sector - ti->begin; 1383 1384 return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); 1385 } 1386 1387 static int crypt_iterate_devices(struct dm_target *ti, 1388 iterate_devices_callout_fn fn, void *data) 1389 { 1390 struct crypt_config *cc = ti->private; 1391 1392 return fn(ti, cc->dev, cc->start, ti->len, data); 1393 } 1394 1395 static struct target_type crypt_target = { 1396 .name = "crypt", 1397 .version = {1, 7, 0}, 1398 .module = THIS_MODULE, 1399 .ctr = crypt_ctr, 1400 .dtr = crypt_dtr, 1401 .map = crypt_map, 1402 .status = crypt_status, 1403 .postsuspend = crypt_postsuspend, 1404 .preresume = crypt_preresume, 1405 .resume = crypt_resume, 1406 .message = crypt_message, 1407 .merge = crypt_merge, 1408 .iterate_devices = crypt_iterate_devices, 1409 }; 1410 1411 static int __init dm_crypt_init(void) 1412 { 1413 int r; 1414 1415 _crypt_io_pool = KMEM_CACHE(dm_crypt_io, 0); 1416 if (!_crypt_io_pool) 1417 return -ENOMEM; 1418 1419 r = dm_register_target(&crypt_target); 1420 if (r < 0) { 1421 DMERR("register failed %d", r); 1422 kmem_cache_destroy(_crypt_io_pool); 1423 } 1424 1425 return r; 1426 } 1427 1428 static void __exit dm_crypt_exit(void) 1429 { 1430 dm_unregister_target(&crypt_target); 1431 kmem_cache_destroy(_crypt_io_pool); 1432 } 1433 1434 module_init(dm_crypt_init); 1435 module_exit(dm_crypt_exit); 1436 1437 MODULE_AUTHOR("Christophe Saout <christophe@saout.de>"); 1438 MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption"); 1439 MODULE_LICENSE("GPL"); 1440