linux/drivers/md/dm-crypt.c
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   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 */
  37struct 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 */
  52struct 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
  65struct 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
  72struct crypt_config;
  73
  74struct 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
  86struct iv_essiv_private {
  87        struct crypto_hash *hash_tfm;
  88        u8 *salt;
  89};
  90
  91struct iv_benbi_private {
  92        int shift;
  93};
  94
  95#define LMK_SEED_SIZE 64 /* hash + 0 */
  96struct 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 */
 105enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID };
 106
 107/*
 108 * Duplicated per-CPU state for cipher.
 109 */
 110struct 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 */
 118struct 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
 181static struct kmem_cache *_crypt_io_pool;
 182
 183static void clone_init(struct dm_crypt_io *, struct bio *);
 184static void kcryptd_queue_crypt(struct dm_crypt_io *io);
 185static u8 *iv_of_dmreq(struct crypt_config *cc, struct dm_crypt_request *dmreq);
 186
 187static 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 */
 195static 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
 237static 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
 246static 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 */
 256static 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 */
 283static 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 */
 301static 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
 333static 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
 352static 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
 393bad:
 394        if (hash_tfm && !IS_ERR(hash_tfm))
 395                crypto_free_hash(hash_tfm);
 396        kfree(salt);
 397        return err;
 398}
 399
 400static 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
 412static 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
 436static void crypt_iv_benbi_dtr(struct crypt_config *cc)
 437{
 438}
 439
 440static 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
 453static 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
 461static 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
 473static 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
 500static 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
 513static 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
 523static 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
 575static 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
 591static 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
 611static struct crypt_iv_operations crypt_iv_plain_ops = {
 612        .generator = crypt_iv_plain_gen
 613};
 614
 615static struct crypt_iv_operations crypt_iv_plain64_ops = {
 616        .generator = crypt_iv_plain64_gen
 617};
 618
 619static 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
 627static 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
 633static struct crypt_iv_operations crypt_iv_null_ops = {
 634        .generator = crypt_iv_null_gen
 635};
 636
 637static 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
 646static 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
 661static 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
 667static 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
 673static 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
 680static 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
 735static void kcryptd_async_done(struct crypto_async_request *async_req,
 736                               int error);
 737
 738static 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 */
 756static int crypt_convert(struct crypt_config *cc,
 757                         struct convert_context *ctx)
 758{
 759        struct crypt_cpu *this_cc = this_crypt_config(cc);
 760        int r;
 761
 762        atomic_set(&ctx->cc_pending, 1);
 763
 764        while(ctx->idx_in < ctx->bio_in->bi_vcnt &&
 765              ctx->idx_out < ctx->bio_out->bi_vcnt) {
 766
 767                crypt_alloc_req(cc, ctx);
 768
 769                atomic_inc(&ctx->cc_pending);
 770
 771                r = crypt_convert_block(cc, ctx, this_cc->req);
 772
 773                switch (r) {
 774                /* async */
 775                case -EBUSY:
 776                        wait_for_completion(&ctx->restart);
 777                        INIT_COMPLETION(ctx->restart);
 778                        /* fall through*/
 779                case -EINPROGRESS:
 780                        this_cc->req = NULL;
 781                        ctx->cc_sector++;
 782                        continue;
 783
 784                /* sync */
 785                case 0:
 786                        atomic_dec(&ctx->cc_pending);
 787                        ctx->cc_sector++;
 788                        cond_resched();
 789                        continue;
 790
 791                /* error */
 792                default:
 793                        atomic_dec(&ctx->cc_pending);
 794                        return r;
 795                }
 796        }
 797
 798        return 0;
 799}
 800
 801/*
 802 * Generate a new unfragmented bio with the given size
 803 * This should never violate the device limitations
 804 * May return a smaller bio when running out of pages, indicated by
 805 * *out_of_pages set to 1.
 806 */
 807static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size,
 808                                      unsigned *out_of_pages)
 809{
 810        struct crypt_config *cc = io->cc;
 811        struct bio *clone;
 812        unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
 813        gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
 814        unsigned i, len;
 815        struct page *page;
 816
 817        clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs);
 818        if (!clone)
 819                return NULL;
 820
 821        clone_init(io, clone);
 822        *out_of_pages = 0;
 823
 824        for (i = 0; i < nr_iovecs; i++) {
 825                page = mempool_alloc(cc->page_pool, gfp_mask);
 826                if (!page) {
 827                        *out_of_pages = 1;
 828                        break;
 829                }
 830
 831                /*
 832                 * If additional pages cannot be allocated without waiting,
 833                 * return a partially-allocated bio.  The caller will then try
 834                 * to allocate more bios while submitting this partial bio.
 835                 */
 836                gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT;
 837
 838                len = (size > PAGE_SIZE) ? PAGE_SIZE : size;
 839
 840                if (!bio_add_page(clone, page, len, 0)) {
 841                        mempool_free(page, cc->page_pool);
 842                        break;
 843                }
 844
 845                size -= len;
 846        }
 847
 848        if (!clone->bi_size) {
 849                bio_put(clone);
 850                return NULL;
 851        }
 852
 853        return clone;
 854}
 855
 856static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone)
 857{
 858        unsigned int i;
 859        struct bio_vec *bv;
 860
 861        for (i = 0; i < clone->bi_vcnt; i++) {
 862                bv = bio_iovec_idx(clone, i);
 863                BUG_ON(!bv->bv_page);
 864                mempool_free(bv->bv_page, cc->page_pool);
 865                bv->bv_page = NULL;
 866        }
 867}
 868
 869static struct dm_crypt_io *crypt_io_alloc(struct crypt_config *cc,
 870                                          struct bio *bio, sector_t sector)
 871{
 872        struct dm_crypt_io *io;
 873
 874        io = mempool_alloc(cc->io_pool, GFP_NOIO);
 875        io->cc = cc;
 876        io->base_bio = bio;
 877        io->sector = sector;
 878        io->error = 0;
 879        io->base_io = NULL;
 880        atomic_set(&io->io_pending, 0);
 881
 882        return io;
 883}
 884
 885static void crypt_inc_pending(struct dm_crypt_io *io)
 886{
 887        atomic_inc(&io->io_pending);
 888}
 889
 890/*
 891 * One of the bios was finished. Check for completion of
 892 * the whole request and correctly clean up the buffer.
 893 * If base_io is set, wait for the last fragment to complete.
 894 */
 895static void crypt_dec_pending(struct dm_crypt_io *io)
 896{
 897        struct crypt_config *cc = io->cc;
 898        struct bio *base_bio = io->base_bio;
 899        struct dm_crypt_io *base_io = io->base_io;
 900        int error = io->error;
 901
 902        if (!atomic_dec_and_test(&io->io_pending))
 903                return;
 904
 905        mempool_free(io, cc->io_pool);
 906
 907        if (likely(!base_io))
 908                bio_endio(base_bio, error);
 909        else {
 910                if (error && !base_io->error)
 911                        base_io->error = error;
 912                crypt_dec_pending(base_io);
 913        }
 914}
 915
 916/*
 917 * kcryptd/kcryptd_io:
 918 *
 919 * Needed because it would be very unwise to do decryption in an
 920 * interrupt context.
 921 *
 922 * kcryptd performs the actual encryption or decryption.
 923 *
 924 * kcryptd_io performs the IO submission.
 925 *
 926 * They must be separated as otherwise the final stages could be
 927 * starved by new requests which can block in the first stages due
 928 * to memory allocation.
 929 *
 930 * The work is done per CPU global for all dm-crypt instances.
 931 * They should not depend on each other and do not block.
 932 */
 933static void crypt_endio(struct bio *clone, int error)
 934{
 935        struct dm_crypt_io *io = clone->bi_private;
 936        struct crypt_config *cc = io->cc;
 937        unsigned rw = bio_data_dir(clone);
 938
 939        if (unlikely(!bio_flagged(clone, BIO_UPTODATE) && !error))
 940                error = -EIO;
 941
 942        /*
 943         * free the processed pages
 944         */
 945        if (rw == WRITE)
 946                crypt_free_buffer_pages(cc, clone);
 947
 948        bio_put(clone);
 949
 950        if (rw == READ && !error) {
 951                kcryptd_queue_crypt(io);
 952                return;
 953        }
 954
 955        if (unlikely(error))
 956                io->error = error;
 957
 958        crypt_dec_pending(io);
 959}
 960
 961static void clone_init(struct dm_crypt_io *io, struct bio *clone)
 962{
 963        struct crypt_config *cc = io->cc;
 964
 965        clone->bi_private = io;
 966        clone->bi_end_io  = crypt_endio;
 967        clone->bi_bdev    = cc->dev->bdev;
 968        clone->bi_rw      = io->base_bio->bi_rw;
 969}
 970
 971static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp)
 972{
 973        struct crypt_config *cc = io->cc;
 974        struct bio *base_bio = io->base_bio;
 975        struct bio *clone;
 976
 977        /*
 978         * The block layer might modify the bvec array, so always
 979         * copy the required bvecs because we need the original
 980         * one in order to decrypt the whole bio data *afterwards*.
 981         */
 982        clone = bio_clone_bioset(base_bio, gfp, cc->bs);
 983        if (!clone)
 984                return 1;
 985
 986        crypt_inc_pending(io);
 987
 988        clone_init(io, clone);
 989        clone->bi_sector = cc->start + io->sector;
 990
 991        generic_make_request(clone);
 992        return 0;
 993}
 994
 995static void kcryptd_io_write(struct dm_crypt_io *io)
 996{
 997        struct bio *clone = io->ctx.bio_out;
 998        generic_make_request(clone);
 999}
1000
1001static void kcryptd_io(struct work_struct *work)
1002{
1003        struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
1004
1005        if (bio_data_dir(io->base_bio) == READ) {
1006                crypt_inc_pending(io);
1007                if (kcryptd_io_read(io, GFP_NOIO))
1008                        io->error = -ENOMEM;
1009                crypt_dec_pending(io);
1010        } else
1011                kcryptd_io_write(io);
1012}
1013
1014static void kcryptd_queue_io(struct dm_crypt_io *io)
1015{
1016        struct crypt_config *cc = io->cc;
1017
1018        INIT_WORK(&io->work, kcryptd_io);
1019        queue_work(cc->io_queue, &io->work);
1020}
1021
1022static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io, int async)
1023{
1024        struct bio *clone = io->ctx.bio_out;
1025        struct crypt_config *cc = io->cc;
1026
1027        if (unlikely(io->error < 0)) {
1028                crypt_free_buffer_pages(cc, clone);
1029                bio_put(clone);
1030                crypt_dec_pending(io);
1031                return;
1032        }
1033
1034        /* crypt_convert should have filled the clone bio */
1035        BUG_ON(io->ctx.idx_out < clone->bi_vcnt);
1036
1037        clone->bi_sector = cc->start + io->sector;
1038
1039        if (async)
1040                kcryptd_queue_io(io);
1041        else
1042                generic_make_request(clone);
1043}
1044
1045static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
1046{
1047        struct crypt_config *cc = io->cc;
1048        struct bio *clone;
1049        struct dm_crypt_io *new_io;
1050        int crypt_finished;
1051        unsigned out_of_pages = 0;
1052        unsigned remaining = io->base_bio->bi_size;
1053        sector_t sector = io->sector;
1054        int r;
1055
1056        /*
1057         * Prevent io from disappearing until this function completes.
1058         */
1059        crypt_inc_pending(io);
1060        crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, sector);
1061
1062        /*
1063         * The allocated buffers can be smaller than the whole bio,
1064         * so repeat the whole process until all the data can be handled.
1065         */
1066        while (remaining) {
1067                clone = crypt_alloc_buffer(io, remaining, &out_of_pages);
1068                if (unlikely(!clone)) {
1069                        io->error = -ENOMEM;
1070                        break;
1071                }
1072
1073                io->ctx.bio_out = clone;
1074                io->ctx.idx_out = 0;
1075
1076                remaining -= clone->bi_size;
1077                sector += bio_sectors(clone);
1078
1079                crypt_inc_pending(io);
1080
1081                r = crypt_convert(cc, &io->ctx);
1082                if (r < 0)
1083                        io->error = -EIO;
1084
1085                crypt_finished = atomic_dec_and_test(&io->ctx.cc_pending);
1086
1087                /* Encryption was already finished, submit io now */
1088                if (crypt_finished) {
1089                        kcryptd_crypt_write_io_submit(io, 0);
1090
1091                        /*
1092                         * If there was an error, do not try next fragments.
1093                         * For async, error is processed in async handler.
1094                         */
1095                        if (unlikely(r < 0))
1096                                break;
1097
1098                        io->sector = sector;
1099                }
1100
1101                /*
1102                 * Out of memory -> run queues
1103                 * But don't wait if split was due to the io size restriction
1104                 */
1105                if (unlikely(out_of_pages))
1106                        congestion_wait(BLK_RW_ASYNC, HZ/100);
1107
1108                /*
1109                 * With async crypto it is unsafe to share the crypto context
1110                 * between fragments, so switch to a new dm_crypt_io structure.
1111                 */
1112                if (unlikely(!crypt_finished && remaining)) {
1113                        new_io = crypt_io_alloc(io->cc, io->base_bio,
1114                                                sector);
1115                        crypt_inc_pending(new_io);
1116                        crypt_convert_init(cc, &new_io->ctx, NULL,
1117                                           io->base_bio, sector);
1118                        new_io->ctx.idx_in = io->ctx.idx_in;
1119                        new_io->ctx.offset_in = io->ctx.offset_in;
1120
1121                        /*
1122                         * Fragments after the first use the base_io
1123                         * pending count.
1124                         */
1125                        if (!io->base_io)
1126                                new_io->base_io = io;
1127                        else {
1128                                new_io->base_io = io->base_io;
1129                                crypt_inc_pending(io->base_io);
1130                                crypt_dec_pending(io);
1131                        }
1132
1133                        io = new_io;
1134                }
1135        }
1136
1137        crypt_dec_pending(io);
1138}
1139
1140static void kcryptd_crypt_read_done(struct dm_crypt_io *io)
1141{
1142        crypt_dec_pending(io);
1143}
1144
1145static void kcryptd_crypt_read_convert(struct dm_crypt_io *io)
1146{
1147        struct crypt_config *cc = io->cc;
1148        int r = 0;
1149
1150        crypt_inc_pending(io);
1151
1152        crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio,
1153                           io->sector);
1154
1155        r = crypt_convert(cc, &io->ctx);
1156        if (r < 0)
1157                io->error = -EIO;
1158
1159        if (atomic_dec_and_test(&io->ctx.cc_pending))
1160                kcryptd_crypt_read_done(io);
1161
1162        crypt_dec_pending(io);
1163}
1164
1165static void kcryptd_async_done(struct crypto_async_request *async_req,
1166                               int error)
1167{
1168        struct dm_crypt_request *dmreq = async_req->data;
1169        struct convert_context *ctx = dmreq->ctx;
1170        struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx);
1171        struct crypt_config *cc = io->cc;
1172
1173        if (error == -EINPROGRESS) {
1174                complete(&ctx->restart);
1175                return;
1176        }
1177
1178        if (!error && cc->iv_gen_ops && cc->iv_gen_ops->post)
1179                error = cc->iv_gen_ops->post(cc, iv_of_dmreq(cc, dmreq), dmreq);
1180
1181        if (error < 0)
1182                io->error = -EIO;
1183
1184        mempool_free(req_of_dmreq(cc, dmreq), cc->req_pool);
1185
1186        if (!atomic_dec_and_test(&ctx->cc_pending))
1187                return;
1188
1189        if (bio_data_dir(io->base_bio) == READ)
1190                kcryptd_crypt_read_done(io);
1191        else
1192                kcryptd_crypt_write_io_submit(io, 1);
1193}
1194
1195static void kcryptd_crypt(struct work_struct *work)
1196{
1197        struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
1198
1199        if (bio_data_dir(io->base_bio) == READ)
1200                kcryptd_crypt_read_convert(io);
1201        else
1202                kcryptd_crypt_write_convert(io);
1203}
1204
1205static void kcryptd_queue_crypt(struct dm_crypt_io *io)
1206{
1207        struct crypt_config *cc = io->cc;
1208
1209        INIT_WORK(&io->work, kcryptd_crypt);
1210        queue_work(cc->crypt_queue, &io->work);
1211}
1212
1213/*
1214 * Decode key from its hex representation
1215 */
1216static int crypt_decode_key(u8 *key, char *hex, unsigned int size)
1217{
1218        char buffer[3];
1219        unsigned int i;
1220
1221        buffer[2] = '\0';
1222
1223        for (i = 0; i < size; i++) {
1224                buffer[0] = *hex++;
1225                buffer[1] = *hex++;
1226
1227                if (kstrtou8(buffer, 16, &key[i]))
1228                        return -EINVAL;
1229        }
1230
1231        if (*hex != '\0')
1232                return -EINVAL;
1233
1234        return 0;
1235}
1236
1237/*
1238 * Encode key into its hex representation
1239 */
1240static void crypt_encode_key(char *hex, u8 *key, unsigned int size)
1241{
1242        unsigned int i;
1243
1244        for (i = 0; i < size; i++) {
1245                sprintf(hex, "%02x", *key);
1246                hex += 2;
1247                key++;
1248        }
1249}
1250
1251static void crypt_free_tfms(struct crypt_config *cc)
1252{
1253        unsigned i;
1254
1255        if (!cc->tfms)
1256                return;
1257
1258        for (i = 0; i < cc->tfms_count; i++)
1259                if (cc->tfms[i] && !IS_ERR(cc->tfms[i])) {
1260                        crypto_free_ablkcipher(cc->tfms[i]);
1261                        cc->tfms[i] = NULL;
1262                }
1263
1264        kfree(cc->tfms);
1265        cc->tfms = NULL;
1266}
1267
1268static int crypt_alloc_tfms(struct crypt_config *cc, char *ciphermode)
1269{
1270        unsigned i;
1271        int err;
1272
1273        cc->tfms = kmalloc(cc->tfms_count * sizeof(struct crypto_ablkcipher *),
1274                           GFP_KERNEL);
1275        if (!cc->tfms)
1276                return -ENOMEM;
1277
1278        for (i = 0; i < cc->tfms_count; i++) {
1279                cc->tfms[i] = crypto_alloc_ablkcipher(ciphermode, 0, 0);
1280                if (IS_ERR(cc->tfms[i])) {
1281                        err = PTR_ERR(cc->tfms[i]);
1282                        crypt_free_tfms(cc);
1283                        return err;
1284                }
1285        }
1286
1287        return 0;
1288}
1289
1290static int crypt_setkey_allcpus(struct crypt_config *cc)
1291{
1292        unsigned subkey_size = cc->key_size >> ilog2(cc->tfms_count);
1293        int err = 0, i, r;
1294
1295        for (i = 0; i < cc->tfms_count; i++) {
1296                r = crypto_ablkcipher_setkey(cc->tfms[i],
1297                                             cc->key + (i * subkey_size),
1298                                             subkey_size);
1299                if (r)
1300                        err = r;
1301        }
1302
1303        return err;
1304}
1305
1306static int crypt_set_key(struct crypt_config *cc, char *key)
1307{
1308        int r = -EINVAL;
1309        int key_string_len = strlen(key);
1310
1311        /* The key size may not be changed. */
1312        if (cc->key_size != (key_string_len >> 1))
1313                goto out;
1314
1315        /* Hyphen (which gives a key_size of zero) means there is no key. */
1316        if (!cc->key_size && strcmp(key, "-"))
1317                goto out;
1318
1319        if (cc->key_size && crypt_decode_key(cc->key, key, cc->key_size) < 0)
1320                goto out;
1321
1322        set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
1323
1324        r = crypt_setkey_allcpus(cc);
1325
1326out:
1327        /* Hex key string not needed after here, so wipe it. */
1328        memset(key, '0', key_string_len);
1329
1330        return r;
1331}
1332
1333static int crypt_wipe_key(struct crypt_config *cc)
1334{
1335        clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
1336        memset(&cc->key, 0, cc->key_size * sizeof(u8));
1337
1338        return crypt_setkey_allcpus(cc);
1339}
1340
1341static void crypt_dtr(struct dm_target *ti)
1342{
1343        struct crypt_config *cc = ti->private;
1344        struct crypt_cpu *cpu_cc;
1345        int cpu;
1346
1347        ti->private = NULL;
1348
1349        if (!cc)
1350                return;
1351
1352        if (cc->io_queue)
1353                destroy_workqueue(cc->io_queue);
1354        if (cc->crypt_queue)
1355                destroy_workqueue(cc->crypt_queue);
1356
1357        if (cc->cpu)
1358                for_each_possible_cpu(cpu) {
1359                        cpu_cc = per_cpu_ptr(cc->cpu, cpu);
1360                        if (cpu_cc->req)
1361                                mempool_free(cpu_cc->req, cc->req_pool);
1362                }
1363
1364        crypt_free_tfms(cc);
1365
1366        if (cc->bs)
1367                bioset_free(cc->bs);
1368
1369        if (cc->page_pool)
1370                mempool_destroy(cc->page_pool);
1371        if (cc->req_pool)
1372                mempool_destroy(cc->req_pool);
1373        if (cc->io_pool)
1374                mempool_destroy(cc->io_pool);
1375
1376        if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
1377                cc->iv_gen_ops->dtr(cc);
1378
1379        if (cc->dev)
1380                dm_put_device(ti, cc->dev);
1381
1382        if (cc->cpu)
1383                free_percpu(cc->cpu);
1384
1385        kzfree(cc->cipher);
1386        kzfree(cc->cipher_string);
1387
1388        /* Must zero key material before freeing */
1389        kzfree(cc);
1390}
1391
1392static int crypt_ctr_cipher(struct dm_target *ti,
1393                            char *cipher_in, char *key)
1394{
1395        struct crypt_config *cc = ti->private;
1396        char *tmp, *cipher, *chainmode, *ivmode, *ivopts, *keycount;
1397        char *cipher_api = NULL;
1398        int ret = -EINVAL;
1399        char dummy;
1400
1401        /* Convert to crypto api definition? */
1402        if (strchr(cipher_in, '(')) {
1403                ti->error = "Bad cipher specification";
1404                return -EINVAL;
1405        }
1406
1407        cc->cipher_string = kstrdup(cipher_in, GFP_KERNEL);
1408        if (!cc->cipher_string)
1409                goto bad_mem;
1410
1411        /*
1412         * Legacy dm-crypt cipher specification
1413         * cipher[:keycount]-mode-iv:ivopts
1414         */
1415        tmp = cipher_in;
1416        keycount = strsep(&tmp, "-");
1417        cipher = strsep(&keycount, ":");
1418
1419        if (!keycount)
1420                cc->tfms_count = 1;
1421        else if (sscanf(keycount, "%u%c", &cc->tfms_count, &dummy) != 1 ||
1422                 !is_power_of_2(cc->tfms_count)) {
1423                ti->error = "Bad cipher key count specification";
1424                return -EINVAL;
1425        }
1426        cc->key_parts = cc->tfms_count;
1427
1428        cc->cipher = kstrdup(cipher, GFP_KERNEL);
1429        if (!cc->cipher)
1430                goto bad_mem;
1431
1432        chainmode = strsep(&tmp, "-");
1433        ivopts = strsep(&tmp, "-");
1434        ivmode = strsep(&ivopts, ":");
1435
1436        if (tmp)
1437                DMWARN("Ignoring unexpected additional cipher options");
1438
1439        cc->cpu = __alloc_percpu(sizeof(*(cc->cpu)),
1440                                 __alignof__(struct crypt_cpu));
1441        if (!cc->cpu) {
1442                ti->error = "Cannot allocate per cpu state";
1443                goto bad_mem;
1444        }
1445
1446        /*
1447         * For compatibility with the original dm-crypt mapping format, if
1448         * only the cipher name is supplied, use cbc-plain.
1449         */
1450        if (!chainmode || (!strcmp(chainmode, "plain") && !ivmode)) {
1451                chainmode = "cbc";
1452                ivmode = "plain";
1453        }
1454
1455        if (strcmp(chainmode, "ecb") && !ivmode) {
1456                ti->error = "IV mechanism required";
1457                return -EINVAL;
1458        }
1459
1460        cipher_api = kmalloc(CRYPTO_MAX_ALG_NAME, GFP_KERNEL);
1461        if (!cipher_api)
1462                goto bad_mem;
1463
1464        ret = snprintf(cipher_api, CRYPTO_MAX_ALG_NAME,
1465                       "%s(%s)", chainmode, cipher);
1466        if (ret < 0) {
1467                kfree(cipher_api);
1468                goto bad_mem;
1469        }
1470
1471        /* Allocate cipher */
1472        ret = crypt_alloc_tfms(cc, cipher_api);
1473        if (ret < 0) {
1474                ti->error = "Error allocating crypto tfm";
1475                goto bad;
1476        }
1477
1478        /* Initialize and set key */
1479        ret = crypt_set_key(cc, key);
1480        if (ret < 0) {
1481                ti->error = "Error decoding and setting key";
1482                goto bad;
1483        }
1484
1485        /* Initialize IV */
1486        cc->iv_size = crypto_ablkcipher_ivsize(any_tfm(cc));
1487        if (cc->iv_size)
1488                /* at least a 64 bit sector number should fit in our buffer */
1489                cc->iv_size = max(cc->iv_size,
1490                                  (unsigned int)(sizeof(u64) / sizeof(u8)));
1491        else if (ivmode) {
1492                DMWARN("Selected cipher does not support IVs");
1493                ivmode = NULL;
1494        }
1495
1496        /* Choose ivmode, see comments at iv code. */
1497        if (ivmode == NULL)
1498                cc->iv_gen_ops = NULL;
1499        else if (strcmp(ivmode, "plain") == 0)
1500                cc->iv_gen_ops = &crypt_iv_plain_ops;
1501        else if (strcmp(ivmode, "plain64") == 0)
1502                cc->iv_gen_ops = &crypt_iv_plain64_ops;
1503        else if (strcmp(ivmode, "essiv") == 0)
1504                cc->iv_gen_ops = &crypt_iv_essiv_ops;
1505        else if (strcmp(ivmode, "benbi") == 0)
1506                cc->iv_gen_ops = &crypt_iv_benbi_ops;
1507        else if (strcmp(ivmode, "null") == 0)
1508                cc->iv_gen_ops = &crypt_iv_null_ops;
1509        else if (strcmp(ivmode, "lmk") == 0) {
1510                cc->iv_gen_ops = &crypt_iv_lmk_ops;
1511                /* Version 2 and 3 is recognised according
1512                 * to length of provided multi-key string.
1513                 * If present (version 3), last key is used as IV seed.
1514                 */
1515                if (cc->key_size % cc->key_parts)
1516                        cc->key_parts++;
1517        } else {
1518                ret = -EINVAL;
1519                ti->error = "Invalid IV mode";
1520                goto bad;
1521        }
1522
1523        /* Allocate IV */
1524        if (cc->iv_gen_ops && cc->iv_gen_ops->ctr) {
1525                ret = cc->iv_gen_ops->ctr(cc, ti, ivopts);
1526                if (ret < 0) {
1527                        ti->error = "Error creating IV";
1528                        goto bad;
1529                }
1530        }
1531
1532        /* Initialize IV (set keys for ESSIV etc) */
1533        if (cc->iv_gen_ops && cc->iv_gen_ops->init) {
1534                ret = cc->iv_gen_ops->init(cc);
1535                if (ret < 0) {
1536                        ti->error = "Error initialising IV";
1537                        goto bad;
1538                }
1539        }
1540
1541        ret = 0;
1542bad:
1543        kfree(cipher_api);
1544        return ret;
1545
1546bad_mem:
1547        ti->error = "Cannot allocate cipher strings";
1548        return -ENOMEM;
1549}
1550
1551/*
1552 * Construct an encryption mapping:
1553 * <cipher> <key> <iv_offset> <dev_path> <start>
1554 */
1555static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
1556{
1557        struct crypt_config *cc;
1558        unsigned int key_size, opt_params;
1559        unsigned long long tmpll;
1560        int ret;
1561        struct dm_arg_set as;
1562        const char *opt_string;
1563        char dummy;
1564
1565        static struct dm_arg _args[] = {
1566                {0, 1, "Invalid number of feature args"},
1567        };
1568
1569        if (argc < 5) {
1570                ti->error = "Not enough arguments";
1571                return -EINVAL;
1572        }
1573
1574        key_size = strlen(argv[1]) >> 1;
1575
1576        cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
1577        if (!cc) {
1578                ti->error = "Cannot allocate encryption context";
1579                return -ENOMEM;
1580        }
1581        cc->key_size = key_size;
1582
1583        ti->private = cc;
1584        ret = crypt_ctr_cipher(ti, argv[0], argv[1]);
1585        if (ret < 0)
1586                goto bad;
1587
1588        ret = -ENOMEM;
1589        cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool);
1590        if (!cc->io_pool) {
1591                ti->error = "Cannot allocate crypt io mempool";
1592                goto bad;
1593        }
1594
1595        cc->dmreq_start = sizeof(struct ablkcipher_request);
1596        cc->dmreq_start += crypto_ablkcipher_reqsize(any_tfm(cc));
1597        cc->dmreq_start = ALIGN(cc->dmreq_start, crypto_tfm_ctx_alignment());
1598        cc->dmreq_start += crypto_ablkcipher_alignmask(any_tfm(cc)) &
1599                           ~(crypto_tfm_ctx_alignment() - 1);
1600
1601        cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start +
1602                        sizeof(struct dm_crypt_request) + cc->iv_size);
1603        if (!cc->req_pool) {
1604                ti->error = "Cannot allocate crypt request mempool";
1605                goto bad;
1606        }
1607
1608        cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0);
1609        if (!cc->page_pool) {
1610                ti->error = "Cannot allocate page mempool";
1611                goto bad;
1612        }
1613
1614        cc->bs = bioset_create(MIN_IOS, 0);
1615        if (!cc->bs) {
1616                ti->error = "Cannot allocate crypt bioset";
1617                goto bad;
1618        }
1619
1620        ret = -EINVAL;
1621        if (sscanf(argv[2], "%llu%c", &tmpll, &dummy) != 1) {
1622                ti->error = "Invalid iv_offset sector";
1623                goto bad;
1624        }
1625        cc->iv_offset = tmpll;
1626
1627        if (dm_get_device(ti, argv[3], dm_table_get_mode(ti->table), &cc->dev)) {
1628                ti->error = "Device lookup failed";
1629                goto bad;
1630        }
1631
1632        if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1) {
1633                ti->error = "Invalid device sector";
1634                goto bad;
1635        }
1636        cc->start = tmpll;
1637
1638        argv += 5;
1639        argc -= 5;
1640
1641        /* Optional parameters */
1642        if (argc) {
1643                as.argc = argc;
1644                as.argv = argv;
1645
1646                ret = dm_read_arg_group(_args, &as, &opt_params, &ti->error);
1647                if (ret)
1648                        goto bad;
1649
1650                opt_string = dm_shift_arg(&as);
1651
1652                if (opt_params == 1 && opt_string &&
1653                    !strcasecmp(opt_string, "allow_discards"))
1654                        ti->num_discard_requests = 1;
1655                else if (opt_params) {
1656                        ret = -EINVAL;
1657                        ti->error = "Invalid feature arguments";
1658                        goto bad;
1659                }
1660        }
1661
1662        ret = -ENOMEM;
1663        cc->io_queue = alloc_workqueue("kcryptd_io",
1664                                       WQ_NON_REENTRANT|
1665                                       WQ_MEM_RECLAIM,
1666                                       1);
1667        if (!cc->io_queue) {
1668                ti->error = "Couldn't create kcryptd io queue";
1669                goto bad;
1670        }
1671
1672        cc->crypt_queue = alloc_workqueue("kcryptd",
1673                                          WQ_NON_REENTRANT|
1674                                          WQ_CPU_INTENSIVE|
1675                                          WQ_MEM_RECLAIM,
1676                                          1);
1677        if (!cc->crypt_queue) {
1678                ti->error = "Couldn't create kcryptd queue";
1679                goto bad;
1680        }
1681
1682        ti->num_flush_requests = 1;
1683        ti->discard_zeroes_data_unsupported = true;
1684
1685        return 0;
1686
1687bad:
1688        crypt_dtr(ti);
1689        return ret;
1690}
1691
1692static int crypt_map(struct dm_target *ti, struct bio *bio,
1693                     union map_info *map_context)
1694{
1695        struct dm_crypt_io *io;
1696        struct crypt_config *cc = ti->private;
1697
1698        /*
1699         * If bio is REQ_FLUSH or REQ_DISCARD, just bypass crypt queues.
1700         * - for REQ_FLUSH device-mapper core ensures that no IO is in-flight
1701         * - for REQ_DISCARD caller must use flush if IO ordering matters
1702         */
1703        if (unlikely(bio->bi_rw & (REQ_FLUSH | REQ_DISCARD))) {
1704                bio->bi_bdev = cc->dev->bdev;
1705                if (bio_sectors(bio))
1706                        bio->bi_sector = cc->start + dm_target_offset(ti, bio->bi_sector);
1707                return DM_MAPIO_REMAPPED;
1708        }
1709
1710        io = crypt_io_alloc(cc, bio, dm_target_offset(ti, bio->bi_sector));
1711
1712        if (bio_data_dir(io->base_bio) == READ) {
1713                if (kcryptd_io_read(io, GFP_NOWAIT))
1714                        kcryptd_queue_io(io);
1715        } else
1716                kcryptd_queue_crypt(io);
1717
1718        return DM_MAPIO_SUBMITTED;
1719}
1720
1721static int crypt_status(struct dm_target *ti, status_type_t type,
1722                        unsigned status_flags, char *result, unsigned maxlen)
1723{
1724        struct crypt_config *cc = ti->private;
1725        unsigned int sz = 0;
1726
1727        switch (type) {
1728        case STATUSTYPE_INFO:
1729                result[0] = '\0';
1730                break;
1731
1732        case STATUSTYPE_TABLE:
1733                DMEMIT("%s ", cc->cipher_string);
1734
1735                if (cc->key_size > 0) {
1736                        if ((maxlen - sz) < ((cc->key_size << 1) + 1))
1737                                return -ENOMEM;
1738
1739                        crypt_encode_key(result + sz, cc->key, cc->key_size);
1740                        sz += cc->key_size << 1;
1741                } else {
1742                        if (sz >= maxlen)
1743                                return -ENOMEM;
1744                        result[sz++] = '-';
1745                }
1746
1747                DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset,
1748                                cc->dev->name, (unsigned long long)cc->start);
1749
1750                if (ti->num_discard_requests)
1751                        DMEMIT(" 1 allow_discards");
1752
1753                break;
1754        }
1755        return 0;
1756}
1757
1758static void crypt_postsuspend(struct dm_target *ti)
1759{
1760        struct crypt_config *cc = ti->private;
1761
1762        set_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1763}
1764
1765static int crypt_preresume(struct dm_target *ti)
1766{
1767        struct crypt_config *cc = ti->private;
1768
1769        if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) {
1770                DMERR("aborting resume - crypt key is not set.");
1771                return -EAGAIN;
1772        }
1773
1774        return 0;
1775}
1776
1777static void crypt_resume(struct dm_target *ti)
1778{
1779        struct crypt_config *cc = ti->private;
1780
1781        clear_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1782}
1783
1784/* Message interface
1785 *      key set <key>
1786 *      key wipe
1787 */
1788static int crypt_message(struct dm_target *ti, unsigned argc, char **argv)
1789{
1790        struct crypt_config *cc = ti->private;
1791        int ret = -EINVAL;
1792
1793        if (argc < 2)
1794                goto error;
1795
1796        if (!strcasecmp(argv[0], "key")) {
1797                if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) {
1798                        DMWARN("not suspended during key manipulation.");
1799                        return -EINVAL;
1800                }
1801                if (argc == 3 && !strcasecmp(argv[1], "set")) {
1802                        ret = crypt_set_key(cc, argv[2]);
1803                        if (ret)
1804                                return ret;
1805                        if (cc->iv_gen_ops && cc->iv_gen_ops->init)
1806                                ret = cc->iv_gen_ops->init(cc);
1807                        return ret;
1808                }
1809                if (argc == 2 && !strcasecmp(argv[1], "wipe")) {
1810                        if (cc->iv_gen_ops && cc->iv_gen_ops->wipe) {
1811                                ret = cc->iv_gen_ops->wipe(cc);
1812                                if (ret)
1813                                        return ret;
1814                        }
1815                        return crypt_wipe_key(cc);
1816                }
1817        }
1818
1819error:
1820        DMWARN("unrecognised message received.");
1821        return -EINVAL;
1822}
1823
1824static int crypt_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
1825                       struct bio_vec *biovec, int max_size)
1826{
1827        struct crypt_config *cc = ti->private;
1828        struct request_queue *q = bdev_get_queue(cc->dev->bdev);
1829
1830        if (!q->merge_bvec_fn)
1831                return max_size;
1832
1833        bvm->bi_bdev = cc->dev->bdev;
1834        bvm->bi_sector = cc->start + dm_target_offset(ti, bvm->bi_sector);
1835
1836        return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
1837}
1838
1839static int crypt_iterate_devices(struct dm_target *ti,
1840                                 iterate_devices_callout_fn fn, void *data)
1841{
1842        struct crypt_config *cc = ti->private;
1843
1844        return fn(ti, cc->dev, cc->start, ti->len, data);
1845}
1846
1847static struct target_type crypt_target = {
1848        .name   = "crypt",
1849        .version = {1, 11, 0},
1850        .module = THIS_MODULE,
1851        .ctr    = crypt_ctr,
1852        .dtr    = crypt_dtr,
1853        .map    = crypt_map,
1854        .status = crypt_status,
1855        .postsuspend = crypt_postsuspend,
1856        .preresume = crypt_preresume,
1857        .resume = crypt_resume,
1858        .message = crypt_message,
1859        .merge  = crypt_merge,
1860        .iterate_devices = crypt_iterate_devices,
1861};
1862
1863static int __init dm_crypt_init(void)
1864{
1865        int r;
1866
1867        _crypt_io_pool = KMEM_CACHE(dm_crypt_io, 0);
1868        if (!_crypt_io_pool)
1869                return -ENOMEM;
1870
1871        r = dm_register_target(&crypt_target);
1872        if (r < 0) {
1873                DMERR("register failed %d", r);
1874                kmem_cache_destroy(_crypt_io_pool);
1875        }
1876
1877        return r;
1878}
1879
1880static void __exit dm_crypt_exit(void)
1881{
1882        dm_unregister_target(&crypt_target);
1883        kmem_cache_destroy(_crypt_io_pool);
1884}
1885
1886module_init(dm_crypt_init);
1887module_exit(dm_crypt_exit);
1888
1889MODULE_AUTHOR("Christophe Saout <christophe@saout.de>");
1890MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption");
1891MODULE_LICENSE("GPL");
1892
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