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