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 sector;
  46        atomic_t pending;
  47};
  48
  49/*
  50 * per bio private data
  51 */
  52struct dm_crypt_io {
  53        struct dm_target *target;
  54        struct bio *base_bio;
  55        struct work_struct work;
  56
  57        struct convert_context ctx;
  58
  59        atomic_t 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        /* ESSIV: struct crypto_cipher *essiv_tfm */
 113        void *iv_private;
 114        struct crypto_ablkcipher *tfms[0];
 115};
 116
 117/*
 118 * The fields in here must be read only after initialization,
 119 * changing state should be in crypt_cpu.
 120 */
 121struct crypt_config {
 122        struct dm_dev *dev;
 123        sector_t start;
 124
 125        /*
 126         * pool for per bio private data, crypto requests and
 127         * encryption requeusts/buffer pages
 128         */
 129        mempool_t *io_pool;
 130        mempool_t *req_pool;
 131        mempool_t *page_pool;
 132        struct bio_set *bs;
 133
 134        struct workqueue_struct *io_queue;
 135        struct workqueue_struct *crypt_queue;
 136
 137        char *cipher;
 138        char *cipher_string;
 139
 140        struct crypt_iv_operations *iv_gen_ops;
 141        union {
 142                struct iv_essiv_private essiv;
 143                struct iv_benbi_private benbi;
 144                struct iv_lmk_private lmk;
 145        } iv_gen_private;
 146        sector_t iv_offset;
 147        unsigned int iv_size;
 148
 149        /*
 150         * Duplicated per cpu state. Access through
 151         * per_cpu_ptr() only.
 152         */
 153        struct crypt_cpu __percpu *cpu;
 154        unsigned tfms_count;
 155
 156        /*
 157         * Layout of each crypto request:
 158         *
 159         *   struct ablkcipher_request
 160         *      context
 161         *      padding
 162         *   struct dm_crypt_request
 163         *      padding
 164         *   IV
 165         *
 166         * The padding is added so that dm_crypt_request and the IV are
 167         * correctly aligned.
 168         */
 169        unsigned int dmreq_start;
 170
 171        unsigned long flags;
 172        unsigned int key_size;
 173        unsigned int key_parts;
 174        u8 key[0];
 175};
 176
 177#define MIN_IOS        16
 178#define MIN_POOL_PAGES 32
 179
 180static struct kmem_cache *_crypt_io_pool;
 181
 182static void clone_init(struct dm_crypt_io *, struct bio *);
 183static void kcryptd_queue_crypt(struct dm_crypt_io *io);
 184static u8 *iv_of_dmreq(struct crypt_config *cc, struct dm_crypt_request *dmreq);
 185
 186static struct crypt_cpu *this_crypt_config(struct crypt_config *cc)
 187{
 188        return this_cpu_ptr(cc->cpu);
 189}
 190
 191/*
 192 * Use this to access cipher attributes that are the same for each CPU.
 193 */
 194static struct crypto_ablkcipher *any_tfm(struct crypt_config *cc)
 195{
 196        return __this_cpu_ptr(cc->cpu)->tfms[0];
 197}
 198
 199/*
 200 * Different IV generation algorithms:
 201 *
 202 * plain: the initial vector is the 32-bit little-endian version of the sector
 203 *        number, padded with zeros if necessary.
 204 *
 205 * plain64: the initial vector is the 64-bit little-endian version of the sector
 206 *        number, padded with zeros if necessary.
 207 *
 208 * essiv: "encrypted sector|salt initial vector", the sector number is
 209 *        encrypted with the bulk cipher using a salt as key. The salt
 210 *        should be derived from the bulk cipher's key via hashing.
 211 *
 212 * benbi: the 64-bit "big-endian 'narrow block'-count", starting at 1
 213 *        (needed for LRW-32-AES and possible other narrow block modes)
 214 *
 215 * null: the initial vector is always zero.  Provides compatibility with
 216 *       obsolete loop_fish2 devices.  Do not use for new devices.
 217 *
 218 * lmk:  Compatible implementation of the block chaining mode used
 219 *       by the Loop-AES block device encryption system
 220 *       designed by Jari Ruusu. See http://loop-aes.sourceforge.net/
 221 *       It operates on full 512 byte sectors and uses CBC
 222 *       with an IV derived from the sector number, the data and
 223 *       optionally extra IV seed.
 224 *       This means that after decryption the first block
 225 *       of sector must be tweaked according to decrypted data.
 226 *       Loop-AES can use three encryption schemes:
 227 *         version 1: is plain aes-cbc mode
 228 *         version 2: uses 64 multikey scheme with lmk IV generator
 229 *         version 3: the same as version 2 with additional IV seed
 230 *                   (it uses 65 keys, last key is used as IV seed)
 231 *
 232 * plumb: unimplemented, see:
 233 * http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454
 234 */
 235
 236static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv,
 237                              struct dm_crypt_request *dmreq)
 238{
 239        memset(iv, 0, cc->iv_size);
 240        *(__le32 *)iv = cpu_to_le32(dmreq->iv_sector & 0xffffffff);
 241
 242        return 0;
 243}
 244
 245static int crypt_iv_plain64_gen(struct crypt_config *cc, u8 *iv,
 246                                struct dm_crypt_request *dmreq)
 247{
 248        memset(iv, 0, cc->iv_size);
 249        *(__le64 *)iv = cpu_to_le64(dmreq->iv_sector);
 250
 251        return 0;
 252}
 253
 254/* Initialise ESSIV - compute salt but no local memory allocations */
 255static int crypt_iv_essiv_init(struct crypt_config *cc)
 256{
 257        struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
 258        struct hash_desc desc;
 259        struct scatterlist sg;
 260        struct crypto_cipher *essiv_tfm;
 261        int err, cpu;
 262
 263        sg_init_one(&sg, cc->key, cc->key_size);
 264        desc.tfm = essiv->hash_tfm;
 265        desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 266
 267        err = crypto_hash_digest(&desc, &sg, cc->key_size, essiv->salt);
 268        if (err)
 269                return err;
 270
 271        for_each_possible_cpu(cpu) {
 272                essiv_tfm = per_cpu_ptr(cc->cpu, cpu)->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
 280        return 0;
 281}
 282
 283/* Wipe salt and reset key derived from volume key */
 284static int crypt_iv_essiv_wipe(struct crypt_config *cc)
 285{
 286        struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
 287        unsigned salt_size = crypto_hash_digestsize(essiv->hash_tfm);
 288        struct crypto_cipher *essiv_tfm;
 289        int cpu, r, err = 0;
 290
 291        memset(essiv->salt, 0, salt_size);
 292
 293        for_each_possible_cpu(cpu) {
 294                essiv_tfm = per_cpu_ptr(cc->cpu, cpu)->iv_private;
 295                r = crypto_cipher_setkey(essiv_tfm, essiv->salt, salt_size);
 296                if (r)
 297                        err = r;
 298        }
 299
 300        return err;
 301}
 302
 303/* Set up per cpu cipher state */
 304static struct crypto_cipher *setup_essiv_cpu(struct crypt_config *cc,
 305                                             struct dm_target *ti,
 306                                             u8 *salt, unsigned saltsize)
 307{
 308        struct crypto_cipher *essiv_tfm;
 309        int err;
 310
 311        /* Setup the essiv_tfm with the given salt */
 312        essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC);
 313        if (IS_ERR(essiv_tfm)) {
 314                ti->error = "Error allocating crypto tfm for ESSIV";
 315                return essiv_tfm;
 316        }
 317
 318        if (crypto_cipher_blocksize(essiv_tfm) !=
 319            crypto_ablkcipher_ivsize(any_tfm(cc))) {
 320                ti->error = "Block size of ESSIV cipher does "
 321                            "not match IV size of block cipher";
 322                crypto_free_cipher(essiv_tfm);
 323                return ERR_PTR(-EINVAL);
 324        }
 325
 326        err = crypto_cipher_setkey(essiv_tfm, salt, saltsize);
 327        if (err) {
 328                ti->error = "Failed to set key for ESSIV cipher";
 329                crypto_free_cipher(essiv_tfm);
 330                return ERR_PTR(err);
 331        }
 332
 333        return essiv_tfm;
 334}
 335
 336static void crypt_iv_essiv_dtr(struct crypt_config *cc)
 337{
 338        int cpu;
 339        struct crypt_cpu *cpu_cc;
 340        struct crypto_cipher *essiv_tfm;
 341        struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
 342
 343        crypto_free_hash(essiv->hash_tfm);
 344        essiv->hash_tfm = NULL;
 345
 346        kzfree(essiv->salt);
 347        essiv->salt = NULL;
 348
 349        for_each_possible_cpu(cpu) {
 350                cpu_cc = per_cpu_ptr(cc->cpu, cpu);
 351                essiv_tfm = cpu_cc->iv_private;
 352
 353                if (essiv_tfm)
 354                        crypto_free_cipher(essiv_tfm);
 355
 356                cpu_cc->iv_private = NULL;
 357        }
 358}
 359
 360static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,
 361                              const char *opts)
 362{
 363        struct crypto_cipher *essiv_tfm = NULL;
 364        struct crypto_hash *hash_tfm = NULL;
 365        u8 *salt = NULL;
 366        int err, cpu;
 367
 368        if (!opts) {
 369                ti->error = "Digest algorithm missing for ESSIV mode";
 370                return -EINVAL;
 371        }
 372
 373        /* Allocate hash algorithm */
 374        hash_tfm = crypto_alloc_hash(opts, 0, CRYPTO_ALG_ASYNC);
 375        if (IS_ERR(hash_tfm)) {
 376                ti->error = "Error initializing ESSIV hash";
 377                err = PTR_ERR(hash_tfm);
 378                goto bad;
 379        }
 380
 381        salt = kzalloc(crypto_hash_digestsize(hash_tfm), GFP_KERNEL);
 382        if (!salt) {
 383                ti->error = "Error kmallocing salt storage in ESSIV";
 384                err = -ENOMEM;
 385                goto bad;
 386        }
 387
 388        cc->iv_gen_private.essiv.salt = salt;
 389        cc->iv_gen_private.essiv.hash_tfm = hash_tfm;
 390
 391        for_each_possible_cpu(cpu) {
 392                essiv_tfm = setup_essiv_cpu(cc, ti, salt,
 393                                        crypto_hash_digestsize(hash_tfm));
 394                if (IS_ERR(essiv_tfm)) {
 395                        crypt_iv_essiv_dtr(cc);
 396                        return PTR_ERR(essiv_tfm);
 397                }
 398                per_cpu_ptr(cc->cpu, cpu)->iv_private = essiv_tfm;
 399        }
 400
 401        return 0;
 402
 403bad:
 404        if (hash_tfm && !IS_ERR(hash_tfm))
 405                crypto_free_hash(hash_tfm);
 406        kfree(salt);
 407        return err;
 408}
 409
 410static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv,
 411                              struct dm_crypt_request *dmreq)
 412{
 413        struct crypto_cipher *essiv_tfm = this_crypt_config(cc)->iv_private;
 414
 415        memset(iv, 0, cc->iv_size);
 416        *(__le64 *)iv = cpu_to_le64(dmreq->iv_sector);
 417        crypto_cipher_encrypt_one(essiv_tfm, iv, iv);
 418
 419        return 0;
 420}
 421
 422static int crypt_iv_benbi_ctr(struct crypt_config *cc, struct dm_target *ti,
 423                              const char *opts)
 424{
 425        unsigned bs = crypto_ablkcipher_blocksize(any_tfm(cc));
 426        int log = ilog2(bs);
 427
 428        /* we need to calculate how far we must shift the sector count
 429         * to get the cipher block count, we use this shift in _gen */
 430
 431        if (1 << log != bs) {
 432                ti->error = "cypher blocksize is not a power of 2";
 433                return -EINVAL;
 434        }
 435
 436        if (log > 9) {
 437                ti->error = "cypher blocksize is > 512";
 438                return -EINVAL;
 439        }
 440
 441        cc->iv_gen_private.benbi.shift = 9 - log;
 442
 443        return 0;
 444}
 445
 446static void crypt_iv_benbi_dtr(struct crypt_config *cc)
 447{
 448}
 449
 450static int crypt_iv_benbi_gen(struct crypt_config *cc, u8 *iv,
 451                              struct dm_crypt_request *dmreq)
 452{
 453        __be64 val;
 454
 455        memset(iv, 0, cc->iv_size - sizeof(u64)); /* rest is cleared below */
 456
 457        val = cpu_to_be64(((u64)dmreq->iv_sector << cc->iv_gen_private.benbi.shift) + 1);
 458        put_unaligned(val, (__be64 *)(iv + cc->iv_size - sizeof(u64)));
 459
 460        return 0;
 461}
 462
 463static int crypt_iv_null_gen(struct crypt_config *cc, u8 *iv,
 464                             struct dm_crypt_request *dmreq)
 465{
 466        memset(iv, 0, cc->iv_size);
 467
 468        return 0;
 469}
 470
 471static void crypt_iv_lmk_dtr(struct crypt_config *cc)
 472{
 473        struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
 474
 475        if (lmk->hash_tfm && !IS_ERR(lmk->hash_tfm))
 476                crypto_free_shash(lmk->hash_tfm);
 477        lmk->hash_tfm = NULL;
 478
 479        kzfree(lmk->seed);
 480        lmk->seed = NULL;
 481}
 482
 483static int crypt_iv_lmk_ctr(struct crypt_config *cc, struct dm_target *ti,
 484                            const char *opts)
 485{
 486        struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
 487
 488        lmk->hash_tfm = crypto_alloc_shash("md5", 0, 0);
 489        if (IS_ERR(lmk->hash_tfm)) {
 490                ti->error = "Error initializing LMK hash";
 491                return PTR_ERR(lmk->hash_tfm);
 492        }
 493
 494        /* No seed in LMK version 2 */
 495        if (cc->key_parts == cc->tfms_count) {
 496                lmk->seed = NULL;
 497                return 0;
 498        }
 499
 500        lmk->seed = kzalloc(LMK_SEED_SIZE, GFP_KERNEL);
 501        if (!lmk->seed) {
 502                crypt_iv_lmk_dtr(cc);
 503                ti->error = "Error kmallocing seed storage in LMK";
 504                return -ENOMEM;
 505        }
 506
 507        return 0;
 508}
 509
 510static int crypt_iv_lmk_init(struct crypt_config *cc)
 511{
 512        struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
 513        int subkey_size = cc->key_size / cc->key_parts;
 514
 515        /* LMK seed is on the position of LMK_KEYS + 1 key */
 516        if (lmk->seed)
 517                memcpy(lmk->seed, cc->key + (cc->tfms_count * subkey_size),
 518                       crypto_shash_digestsize(lmk->hash_tfm));
 519
 520        return 0;
 521}
 522
 523static int crypt_iv_lmk_wipe(struct crypt_config *cc)
 524{
 525        struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
 526
 527        if (lmk->seed)
 528                memset(lmk->seed, 0, LMK_SEED_SIZE);
 529
 530        return 0;
 531}
 532
 533static int crypt_iv_lmk_one(struct crypt_config *cc, u8 *iv,
 534                            struct dm_crypt_request *dmreq,
 535                            u8 *data)
 536{
 537        struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
 538        struct {
 539                struct shash_desc desc;
 540                char ctx[crypto_shash_descsize(lmk->hash_tfm)];
 541        } sdesc;
 542        struct md5_state md5state;
 543        u32 buf[4];
 544        int i, r;
 545
 546        sdesc.desc.tfm = lmk->hash_tfm;
 547        sdesc.desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 548
 549        r = crypto_shash_init(&sdesc.desc);
 550        if (r)
 551                return r;
 552
 553        if (lmk->seed) {
 554                r = crypto_shash_update(&sdesc.desc, lmk->seed, LMK_SEED_SIZE);
 555                if (r)
 556                        return r;
 557        }
 558
 559        /* Sector is always 512B, block size 16, add data of blocks 1-31 */
 560        r = crypto_shash_update(&sdesc.desc, data + 16, 16 * 31);
 561        if (r)
 562                return r;
 563
 564        /* Sector is cropped to 56 bits here */
 565        buf[0] = cpu_to_le32(dmreq->iv_sector & 0xFFFFFFFF);
 566        buf[1] = cpu_to_le32((((u64)dmreq->iv_sector >> 32) & 0x00FFFFFF) | 0x80000000);
 567        buf[2] = cpu_to_le32(4024);
 568        buf[3] = 0;
 569        r = crypto_shash_update(&sdesc.desc, (u8 *)buf, sizeof(buf));
 570        if (r)
 571                return r;
 572
 573        /* No MD5 padding here */
 574        r = crypto_shash_export(&sdesc.desc, &md5state);
 575        if (r)
 576                return r;
 577
 578        for (i = 0; i < MD5_HASH_WORDS; i++)
 579                __cpu_to_le32s(&md5state.hash[i]);
 580        memcpy(iv, &md5state.hash, cc->iv_size);
 581
 582        return 0;
 583}
 584
 585static int crypt_iv_lmk_gen(struct crypt_config *cc, u8 *iv,
 586                            struct dm_crypt_request *dmreq)
 587{
 588        u8 *src;
 589        int r = 0;
 590
 591        if (bio_data_dir(dmreq->ctx->bio_in) == WRITE) {
 592                src = kmap_atomic(sg_page(&dmreq->sg_in), KM_USER0);
 593                r = crypt_iv_lmk_one(cc, iv, dmreq, src + dmreq->sg_in.offset);
 594                kunmap_atomic(src, KM_USER0);
 595        } else
 596                memset(iv, 0, cc->iv_size);
 597
 598        return r;
 599}
 600
 601static int crypt_iv_lmk_post(struct crypt_config *cc, u8 *iv,
 602                             struct dm_crypt_request *dmreq)
 603{
 604        u8 *dst;
 605        int r;
 606
 607        if (bio_data_dir(dmreq->ctx->bio_in) == WRITE)
 608                return 0;
 609
 610        dst = kmap_atomic(sg_page(&dmreq->sg_out), KM_USER0);
 611        r = crypt_iv_lmk_one(cc, iv, dmreq, dst + dmreq->sg_out.offset);
 612
 613        /* Tweak the first block of plaintext sector */
 614        if (!r)
 615                crypto_xor(dst + dmreq->sg_out.offset, iv, cc->iv_size);
 616
 617        kunmap_atomic(dst, KM_USER0);
 618        return r;
 619}
 620
 621static struct crypt_iv_operations crypt_iv_plain_ops = {
 622        .generator = crypt_iv_plain_gen
 623};
 624
 625static struct crypt_iv_operations crypt_iv_plain64_ops = {
 626        .generator = crypt_iv_plain64_gen
 627};
 628
 629static struct crypt_iv_operations crypt_iv_essiv_ops = {
 630        .ctr       = crypt_iv_essiv_ctr,
 631        .dtr       = crypt_iv_essiv_dtr,
 632        .init      = crypt_iv_essiv_init,
 633        .wipe      = crypt_iv_essiv_wipe,
 634        .generator = crypt_iv_essiv_gen
 635};
 636
 637static struct crypt_iv_operations crypt_iv_benbi_ops = {
 638        .ctr       = crypt_iv_benbi_ctr,
 639        .dtr       = crypt_iv_benbi_dtr,
 640        .generator = crypt_iv_benbi_gen
 641};
 642
 643static struct crypt_iv_operations crypt_iv_null_ops = {
 644        .generator = crypt_iv_null_gen
 645};
 646
 647static struct crypt_iv_operations crypt_iv_lmk_ops = {
 648        .ctr       = crypt_iv_lmk_ctr,
 649        .dtr       = crypt_iv_lmk_dtr,
 650        .init      = crypt_iv_lmk_init,
 651        .wipe      = crypt_iv_lmk_wipe,
 652        .generator = crypt_iv_lmk_gen,
 653        .post      = crypt_iv_lmk_post
 654};
 655
 656static void crypt_convert_init(struct crypt_config *cc,
 657                               struct convert_context *ctx,
 658                               struct bio *bio_out, struct bio *bio_in,
 659                               sector_t sector)
 660{
 661        ctx->bio_in = bio_in;
 662        ctx->bio_out = bio_out;
 663        ctx->offset_in = 0;
 664        ctx->offset_out = 0;
 665        ctx->idx_in = bio_in ? bio_in->bi_idx : 0;
 666        ctx->idx_out = bio_out ? bio_out->bi_idx : 0;
 667        ctx->sector = sector + cc->iv_offset;
 668        init_completion(&ctx->restart);
 669}
 670
 671static struct dm_crypt_request *dmreq_of_req(struct crypt_config *cc,
 672                                             struct ablkcipher_request *req)
 673{
 674        return (struct dm_crypt_request *)((char *)req + cc->dmreq_start);
 675}
 676
 677static struct ablkcipher_request *req_of_dmreq(struct crypt_config *cc,
 678                                               struct dm_crypt_request *dmreq)
 679{
 680        return (struct ablkcipher_request *)((char *)dmreq - cc->dmreq_start);
 681}
 682
 683static u8 *iv_of_dmreq(struct crypt_config *cc,
 684                       struct dm_crypt_request *dmreq)
 685{
 686        return (u8 *)ALIGN((unsigned long)(dmreq + 1),
 687                crypto_ablkcipher_alignmask(any_tfm(cc)) + 1);
 688}
 689
 690static int crypt_convert_block(struct crypt_config *cc,
 691                               struct convert_context *ctx,
 692                               struct ablkcipher_request *req)
 693{
 694        struct bio_vec *bv_in = bio_iovec_idx(ctx->bio_in, ctx->idx_in);
 695        struct bio_vec *bv_out = bio_iovec_idx(ctx->bio_out, ctx->idx_out);
 696        struct dm_crypt_request *dmreq;
 697        u8 *iv;
 698        int r = 0;
 699
 700        dmreq = dmreq_of_req(cc, req);
 701        iv = iv_of_dmreq(cc, dmreq);
 702
 703        dmreq->iv_sector = ctx->sector;
 704        dmreq->ctx = ctx;
 705        sg_init_table(&dmreq->sg_in, 1);
 706        sg_set_page(&dmreq->sg_in, bv_in->bv_page, 1 << SECTOR_SHIFT,
 707                    bv_in->bv_offset + ctx->offset_in);
 708
 709        sg_init_table(&dmreq->sg_out, 1);
 710        sg_set_page(&dmreq->sg_out, bv_out->bv_page, 1 << SECTOR_SHIFT,
 711                    bv_out->bv_offset + ctx->offset_out);
 712
 713        ctx->offset_in += 1 << SECTOR_SHIFT;
 714        if (ctx->offset_in >= bv_in->bv_len) {
 715                ctx->offset_in = 0;
 716                ctx->idx_in++;
 717        }
 718
 719        ctx->offset_out += 1 << SECTOR_SHIFT;
 720        if (ctx->offset_out >= bv_out->bv_len) {
 721                ctx->offset_out = 0;
 722                ctx->idx_out++;
 723        }
 724
 725        if (cc->iv_gen_ops) {
 726                r = cc->iv_gen_ops->generator(cc, iv, dmreq);
 727                if (r < 0)
 728                        return r;
 729        }
 730
 731        ablkcipher_request_set_crypt(req, &dmreq->sg_in, &dmreq->sg_out,
 732                                     1 << SECTOR_SHIFT, iv);
 733
 734        if (bio_data_dir(ctx->bio_in) == WRITE)
 735                r = crypto_ablkcipher_encrypt(req);
 736        else
 737                r = crypto_ablkcipher_decrypt(req);
 738
 739        if (!r && cc->iv_gen_ops && cc->iv_gen_ops->post)
 740                r = cc->iv_gen_ops->post(cc, iv, dmreq);
 741
 742        return r;
 743}
 744
 745static void kcryptd_async_done(struct crypto_async_request *async_req,
 746                               int error);
 747
 748static void crypt_alloc_req(struct crypt_config *cc,
 749                            struct convert_context *ctx)
 750{
 751        struct crypt_cpu *this_cc = this_crypt_config(cc);
 752        unsigned key_index = ctx->sector & (cc->tfms_count - 1);
 753
 754        if (!this_cc->req)
 755                this_cc->req = mempool_alloc(cc->req_pool, GFP_NOIO);
 756
 757        ablkcipher_request_set_tfm(this_cc->req, this_cc->tfms[key_index]);
 758        ablkcipher_request_set_callback(this_cc->req,
 759            CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
 760            kcryptd_async_done, dmreq_of_req(cc, this_cc->req));
 761}
 762
 763/*
 764 * Encrypt / decrypt data from one bio to another one (can be the same one)
 765 */
 766static int crypt_convert(struct crypt_config *cc,
 767                         struct convert_context *ctx)
 768{
 769        struct crypt_cpu *this_cc = this_crypt_config(cc);
 770        int r;
 771
 772        atomic_set(&ctx->pending, 1);
 773
 774        while(ctx->idx_in < ctx->bio_in->bi_vcnt &&
 775              ctx->idx_out < ctx->bio_out->bi_vcnt) {
 776
 777                crypt_alloc_req(cc, ctx);
 778
 779                atomic_inc(&ctx->pending);
 780
 781                r = crypt_convert_block(cc, ctx, this_cc->req);
 782
 783                switch (r) {
 784                /* async */
 785                case -EBUSY:
 786                        wait_for_completion(&ctx->restart);
 787                        INIT_COMPLETION(ctx->restart);
 788                        /* fall through*/
 789                case -EINPROGRESS:
 790                        this_cc->req = NULL;
 791                        ctx->sector++;
 792                        continue;
 793
 794                /* sync */
 795                case 0:
 796                        atomic_dec(&ctx->pending);
 797                        ctx->sector++;
 798                        cond_resched();
 799                        continue;
 800
 801                /* error */
 802                default:
 803                        atomic_dec(&ctx->pending);
 804                        return r;
 805                }
 806        }
 807
 808        return 0;
 809}
 810
 811static void dm_crypt_bio_destructor(struct bio *bio)
 812{
 813        struct dm_crypt_io *io = bio->bi_private;
 814        struct crypt_config *cc = io->target->private;
 815
 816        bio_free(bio, cc->bs);
 817}
 818
 819/*
 820 * Generate a new unfragmented bio with the given size
 821 * This should never violate the device limitations
 822 * May return a smaller bio when running out of pages, indicated by
 823 * *out_of_pages set to 1.
 824 */
 825static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size,
 826                                      unsigned *out_of_pages)
 827{
 828        struct crypt_config *cc = io->target->private;
 829        struct bio *clone;
 830        unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
 831        gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
 832        unsigned i, len;
 833        struct page *page;
 834
 835        clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs);
 836        if (!clone)
 837                return NULL;
 838
 839        clone_init(io, clone);
 840        *out_of_pages = 0;
 841
 842        for (i = 0; i < nr_iovecs; i++) {
 843                page = mempool_alloc(cc->page_pool, gfp_mask);
 844                if (!page) {
 845                        *out_of_pages = 1;
 846                        break;
 847                }
 848
 849                /*
 850                 * If additional pages cannot be allocated without waiting,
 851                 * return a partially-allocated bio.  The caller will then try
 852                 * to allocate more bios while submitting this partial bio.
 853                 */
 854                gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT;
 855
 856                len = (size > PAGE_SIZE) ? PAGE_SIZE : size;
 857
 858                if (!bio_add_page(clone, page, len, 0)) {
 859                        mempool_free(page, cc->page_pool);
 860                        break;
 861                }
 862
 863                size -= len;
 864        }
 865
 866        if (!clone->bi_size) {
 867                bio_put(clone);
 868                return NULL;
 869        }
 870
 871        return clone;
 872}
 873
 874static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone)
 875{
 876        unsigned int i;
 877        struct bio_vec *bv;
 878
 879        for (i = 0; i < clone->bi_vcnt; i++) {
 880                bv = bio_iovec_idx(clone, i);
 881                BUG_ON(!bv->bv_page);
 882                mempool_free(bv->bv_page, cc->page_pool);
 883                bv->bv_page = NULL;
 884        }
 885}
 886
 887static struct dm_crypt_io *crypt_io_alloc(struct dm_target *ti,
 888                                          struct bio *bio, sector_t sector)
 889{
 890        struct crypt_config *cc = ti->private;
 891        struct dm_crypt_io *io;
 892
 893        io = mempool_alloc(cc->io_pool, GFP_NOIO);
 894        io->target = ti;
 895        io->base_bio = bio;
 896        io->sector = sector;
 897        io->error = 0;
 898        io->base_io = NULL;
 899        atomic_set(&io->pending, 0);
 900
 901        return io;
 902}
 903
 904static void crypt_inc_pending(struct dm_crypt_io *io)
 905{
 906        atomic_inc(&io->pending);
 907}
 908
 909/*
 910 * One of the bios was finished. Check for completion of
 911 * the whole request and correctly clean up the buffer.
 912 * If base_io is set, wait for the last fragment to complete.
 913 */
 914static void crypt_dec_pending(struct dm_crypt_io *io)
 915{
 916        struct crypt_config *cc = io->target->private;
 917        struct bio *base_bio = io->base_bio;
 918        struct dm_crypt_io *base_io = io->base_io;
 919        int error = io->error;
 920
 921        if (!atomic_dec_and_test(&io->pending))
 922                return;
 923
 924        mempool_free(io, cc->io_pool);
 925
 926        if (likely(!base_io))
 927                bio_endio(base_bio, error);
 928        else {
 929                if (error && !base_io->error)
 930                        base_io->error = error;
 931                crypt_dec_pending(base_io);
 932        }
 933}
 934
 935/*
 936 * kcryptd/kcryptd_io:
 937 *
 938 * Needed because it would be very unwise to do decryption in an
 939 * interrupt context.
 940 *
 941 * kcryptd performs the actual encryption or decryption.
 942 *
 943 * kcryptd_io performs the IO submission.
 944 *
 945 * They must be separated as otherwise the final stages could be
 946 * starved by new requests which can block in the first stages due
 947 * to memory allocation.
 948 *
 949 * The work is done per CPU global for all dm-crypt instances.
 950 * They should not depend on each other and do not block.
 951 */
 952static void crypt_endio(struct bio *clone, int error)
 953{
 954        struct dm_crypt_io *io = clone->bi_private;
 955        struct crypt_config *cc = io->target->private;
 956        unsigned rw = bio_data_dir(clone);
 957
 958        if (unlikely(!bio_flagged(clone, BIO_UPTODATE) && !error))
 959                error = -EIO;
 960
 961        /*
 962         * free the processed pages
 963         */
 964        if (rw == WRITE)
 965                crypt_free_buffer_pages(cc, clone);
 966
 967        bio_put(clone);
 968
 969        if (rw == READ && !error) {
 970                kcryptd_queue_crypt(io);
 971                return;
 972        }
 973
 974        if (unlikely(error))
 975                io->error = error;
 976
 977        crypt_dec_pending(io);
 978}
 979
 980static void clone_init(struct dm_crypt_io *io, struct bio *clone)
 981{
 982        struct crypt_config *cc = io->target->private;
 983
 984        clone->bi_private = io;
 985        clone->bi_end_io  = crypt_endio;
 986        clone->bi_bdev    = cc->dev->bdev;
 987        clone->bi_rw      = io->base_bio->bi_rw;
 988        clone->bi_destructor = dm_crypt_bio_destructor;
 989}
 990
 991static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp)
 992{
 993        struct crypt_config *cc = io->target->private;
 994        struct bio *base_bio = io->base_bio;
 995        struct bio *clone;
 996
 997        /*
 998         * The block layer might modify the bvec array, so always
 999         * copy the required bvecs because we need the original
1000         * one in order to decrypt the whole bio data *afterwards*.
1001         */
1002        clone = bio_alloc_bioset(gfp, bio_segments(base_bio), cc->bs);
1003        if (!clone)
1004                return 1;
1005
1006        crypt_inc_pending(io);
1007
1008        clone_init(io, clone);
1009        clone->bi_idx = 0;
1010        clone->bi_vcnt = bio_segments(base_bio);
1011        clone->bi_size = base_bio->bi_size;
1012        clone->bi_sector = cc->start + io->sector;
1013        memcpy(clone->bi_io_vec, bio_iovec(base_bio),
1014               sizeof(struct bio_vec) * clone->bi_vcnt);
1015
1016        generic_make_request(clone);
1017        return 0;
1018}
1019
1020static void kcryptd_io_write(struct dm_crypt_io *io)
1021{
1022        struct bio *clone = io->ctx.bio_out;
1023        generic_make_request(clone);
1024}
1025
1026static void kcryptd_io(struct work_struct *work)
1027{
1028        struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
1029
1030        if (bio_data_dir(io->base_bio) == READ) {
1031                crypt_inc_pending(io);
1032                if (kcryptd_io_read(io, GFP_NOIO))
1033                        io->error = -ENOMEM;
1034                crypt_dec_pending(io);
1035        } else
1036                kcryptd_io_write(io);
1037}
1038
1039static void kcryptd_queue_io(struct dm_crypt_io *io)
1040{
1041        struct crypt_config *cc = io->target->private;
1042
1043        INIT_WORK(&io->work, kcryptd_io);
1044        queue_work(cc->io_queue, &io->work);
1045}
1046
1047static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io, int async)
1048{
1049        struct bio *clone = io->ctx.bio_out;
1050        struct crypt_config *cc = io->target->private;
1051
1052        if (unlikely(io->error < 0)) {
1053                crypt_free_buffer_pages(cc, clone);
1054                bio_put(clone);
1055                crypt_dec_pending(io);
1056                return;
1057        }
1058
1059        /* crypt_convert should have filled the clone bio */
1060        BUG_ON(io->ctx.idx_out < clone->bi_vcnt);
1061
1062        clone->bi_sector = cc->start + io->sector;
1063
1064        if (async)
1065                kcryptd_queue_io(io);
1066        else
1067                generic_make_request(clone);
1068}
1069
1070static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
1071{
1072        struct crypt_config *cc = io->target->private;
1073        struct bio *clone;
1074        struct dm_crypt_io *new_io;
1075        int crypt_finished;
1076        unsigned out_of_pages = 0;
1077        unsigned remaining = io->base_bio->bi_size;
1078        sector_t sector = io->sector;
1079        int r;
1080
1081        /*
1082         * Prevent io from disappearing until this function completes.
1083         */
1084        crypt_inc_pending(io);
1085        crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, sector);
1086
1087        /*
1088         * The allocated buffers can be smaller than the whole bio,
1089         * so repeat the whole process until all the data can be handled.
1090         */
1091        while (remaining) {
1092                clone = crypt_alloc_buffer(io, remaining, &out_of_pages);
1093                if (unlikely(!clone)) {
1094                        io->error = -ENOMEM;
1095                        break;
1096                }
1097
1098                io->ctx.bio_out = clone;
1099                io->ctx.idx_out = 0;
1100
1101                remaining -= clone->bi_size;
1102                sector += bio_sectors(clone);
1103
1104                crypt_inc_pending(io);
1105
1106                r = crypt_convert(cc, &io->ctx);
1107                if (r < 0)
1108                        io->error = -EIO;
1109
1110                crypt_finished = atomic_dec_and_test(&io->ctx.pending);
1111
1112                /* Encryption was already finished, submit io now */
1113                if (crypt_finished) {
1114                        kcryptd_crypt_write_io_submit(io, 0);
1115
1116                        /*
1117                         * If there was an error, do not try next fragments.
1118                         * For async, error is processed in async handler.
1119                         */
1120                        if (unlikely(r < 0))
1121                                break;
1122
1123                        io->sector = sector;
1124                }
1125
1126                /*
1127                 * Out of memory -> run queues
1128                 * But don't wait if split was due to the io size restriction
1129                 */
1130                if (unlikely(out_of_pages))
1131                        congestion_wait(BLK_RW_ASYNC, HZ/100);
1132
1133                /*
1134                 * With async crypto it is unsafe to share the crypto context
1135                 * between fragments, so switch to a new dm_crypt_io structure.
1136                 */
1137                if (unlikely(!crypt_finished && remaining)) {
1138                        new_io = crypt_io_alloc(io->target, io->base_bio,
1139                                                sector);
1140                        crypt_inc_pending(new_io);
1141                        crypt_convert_init(cc, &new_io->ctx, NULL,
1142                                           io->base_bio, sector);
1143                        new_io->ctx.idx_in = io->ctx.idx_in;
1144                        new_io->ctx.offset_in = io->ctx.offset_in;
1145
1146                        /*
1147                         * Fragments after the first use the base_io
1148                         * pending count.
1149                         */
1150                        if (!io->base_io)
1151                                new_io->base_io = io;
1152                        else {
1153                                new_io->base_io = io->base_io;
1154                                crypt_inc_pending(io->base_io);
1155                                crypt_dec_pending(io);
1156                        }
1157
1158                        io = new_io;
1159                }
1160        }
1161
1162        crypt_dec_pending(io);
1163}
1164
1165static void kcryptd_crypt_read_done(struct dm_crypt_io *io)
1166{
1167        crypt_dec_pending(io);
1168}
1169
1170static void kcryptd_crypt_read_convert(struct dm_crypt_io *io)
1171{
1172        struct crypt_config *cc = io->target->private;
1173        int r = 0;
1174
1175        crypt_inc_pending(io);
1176
1177        crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio,
1178                           io->sector);
1179
1180        r = crypt_convert(cc, &io->ctx);
1181        if (r < 0)
1182                io->error = -EIO;
1183
1184        if (atomic_dec_and_test(&io->ctx.pending))
1185                kcryptd_crypt_read_done(io);
1186
1187        crypt_dec_pending(io);
1188}
1189
1190static void kcryptd_async_done(struct crypto_async_request *async_req,
1191                               int error)
1192{
1193        struct dm_crypt_request *dmreq = async_req->data;
1194        struct convert_context *ctx = dmreq->ctx;
1195        struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx);
1196        struct crypt_config *cc = io->target->private;
1197
1198        if (error == -EINPROGRESS) {
1199                complete(&ctx->restart);
1200                return;
1201        }
1202
1203        if (!error && cc->iv_gen_ops && cc->iv_gen_ops->post)
1204                error = cc->iv_gen_ops->post(cc, iv_of_dmreq(cc, dmreq), dmreq);
1205
1206        if (error < 0)
1207                io->error = -EIO;
1208
1209        mempool_free(req_of_dmreq(cc, dmreq), cc->req_pool);
1210
1211        if (!atomic_dec_and_test(&ctx->pending))
1212                return;
1213
1214        if (bio_data_dir(io->base_bio) == READ)
1215                kcryptd_crypt_read_done(io);
1216        else
1217                kcryptd_crypt_write_io_submit(io, 1);
1218}
1219
1220static void kcryptd_crypt(struct work_struct *work)
1221{
1222        struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
1223
1224        if (bio_data_dir(io->base_bio) == READ)
1225                kcryptd_crypt_read_convert(io);
1226        else
1227                kcryptd_crypt_write_convert(io);
1228}
1229
1230static void kcryptd_queue_crypt(struct dm_crypt_io *io)
1231{
1232        struct crypt_config *cc = io->target->private;
1233
1234        INIT_WORK(&io->work, kcryptd_crypt);
1235        queue_work(cc->crypt_queue, &io->work);
1236}
1237
1238/*
1239 * Decode key from its hex representation
1240 */
1241static int crypt_decode_key(u8 *key, char *hex, unsigned int size)
1242{
1243        char buffer[3];
1244        char *endp;
1245        unsigned int i;
1246
1247        buffer[2] = '\0';
1248
1249        for (i = 0; i < size; i++) {
1250                buffer[0] = *hex++;
1251                buffer[1] = *hex++;
1252
1253                key[i] = (u8)simple_strtoul(buffer, &endp, 16);
1254
1255                if (endp != &buffer[2])
1256                        return -EINVAL;
1257        }
1258
1259        if (*hex != '\0')
1260                return -EINVAL;
1261
1262        return 0;
1263}
1264
1265/*
1266 * Encode key into its hex representation
1267 */
1268static void crypt_encode_key(char *hex, u8 *key, unsigned int size)
1269{
1270        unsigned int i;
1271
1272        for (i = 0; i < size; i++) {
1273                sprintf(hex, "%02x", *key);
1274                hex += 2;
1275                key++;
1276        }
1277}
1278
1279static void crypt_free_tfms(struct crypt_config *cc, int cpu)
1280{
1281        struct crypt_cpu *cpu_cc = per_cpu_ptr(cc->cpu, cpu);
1282        unsigned i;
1283
1284        for (i = 0; i < cc->tfms_count; i++)
1285                if (cpu_cc->tfms[i] && !IS_ERR(cpu_cc->tfms[i])) {
1286                        crypto_free_ablkcipher(cpu_cc->tfms[i]);
1287                        cpu_cc->tfms[i] = NULL;
1288                }
1289}
1290
1291static int crypt_alloc_tfms(struct crypt_config *cc, int cpu, char *ciphermode)
1292{
1293        struct crypt_cpu *cpu_cc = per_cpu_ptr(cc->cpu, cpu);
1294        unsigned i;
1295        int err;
1296
1297        for (i = 0; i < cc->tfms_count; i++) {
1298                cpu_cc->tfms[i] = crypto_alloc_ablkcipher(ciphermode, 0, 0);
1299                if (IS_ERR(cpu_cc->tfms[i])) {
1300                        err = PTR_ERR(cpu_cc->tfms[i]);
1301                        crypt_free_tfms(cc, cpu);
1302                        return err;
1303                }
1304        }
1305
1306        return 0;
1307}
1308
1309static int crypt_setkey_allcpus(struct crypt_config *cc)
1310{
1311        unsigned subkey_size = cc->key_size >> ilog2(cc->tfms_count);
1312        int cpu, err = 0, i, r;
1313
1314        for_each_possible_cpu(cpu) {
1315                for (i = 0; i < cc->tfms_count; i++) {
1316                        r = crypto_ablkcipher_setkey(per_cpu_ptr(cc->cpu, cpu)->tfms[i],
1317                                                     cc->key + (i * subkey_size), subkey_size);
1318                        if (r)
1319                                err = r;
1320                }
1321        }
1322
1323        return err;
1324}
1325
1326static int crypt_set_key(struct crypt_config *cc, char *key)
1327{
1328        int r = -EINVAL;
1329        int key_string_len = strlen(key);
1330
1331        /* The key size may not be changed. */
1332        if (cc->key_size != (key_string_len >> 1))
1333                goto out;
1334
1335        /* Hyphen (which gives a key_size of zero) means there is no key. */
1336        if (!cc->key_size && strcmp(key, "-"))
1337                goto out;
1338
1339        if (cc->key_size && crypt_decode_key(cc->key, key, cc->key_size) < 0)
1340                goto out;
1341
1342        set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
1343
1344        r = crypt_setkey_allcpus(cc);
1345
1346out:
1347        /* Hex key string not needed after here, so wipe it. */
1348        memset(key, '0', key_string_len);
1349
1350        return r;
1351}
1352
1353static int crypt_wipe_key(struct crypt_config *cc)
1354{
1355        clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
1356        memset(&cc->key, 0, cc->key_size * sizeof(u8));
1357
1358        return crypt_setkey_allcpus(cc);
1359}
1360
1361static void crypt_dtr(struct dm_target *ti)
1362{
1363        struct crypt_config *cc = ti->private;
1364        struct crypt_cpu *cpu_cc;
1365        int cpu;
1366
1367        ti->private = NULL;
1368
1369        if (!cc)
1370                return;
1371
1372        if (cc->io_queue)
1373                destroy_workqueue(cc->io_queue);
1374        if (cc->crypt_queue)
1375                destroy_workqueue(cc->crypt_queue);
1376
1377        if (cc->cpu)
1378                for_each_possible_cpu(cpu) {
1379                        cpu_cc = per_cpu_ptr(cc->cpu, cpu);
1380                        if (cpu_cc->req)
1381                                mempool_free(cpu_cc->req, cc->req_pool);
1382                        crypt_free_tfms(cc, cpu);
1383                }
1384
1385        if (cc->bs)
1386                bioset_free(cc->bs);
1387
1388        if (cc->page_pool)
1389                mempool_destroy(cc->page_pool);
1390        if (cc->req_pool)
1391                mempool_destroy(cc->req_pool);
1392        if (cc->io_pool)
1393                mempool_destroy(cc->io_pool);
1394
1395        if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
1396                cc->iv_gen_ops->dtr(cc);
1397
1398        if (cc->dev)
1399                dm_put_device(ti, cc->dev);
1400
1401        if (cc->cpu)
1402                free_percpu(cc->cpu);
1403
1404        kzfree(cc->cipher);
1405        kzfree(cc->cipher_string);
1406
1407        /* Must zero key material before freeing */
1408        kzfree(cc);
1409}
1410
1411static int crypt_ctr_cipher(struct dm_target *ti,
1412                            char *cipher_in, char *key)
1413{
1414        struct crypt_config *cc = ti->private;
1415        char *tmp, *cipher, *chainmode, *ivmode, *ivopts, *keycount;
1416        char *cipher_api = NULL;
1417        int cpu, ret = -EINVAL;
1418
1419        /* Convert to crypto api definition? */
1420        if (strchr(cipher_in, '(')) {
1421                ti->error = "Bad cipher specification";
1422                return -EINVAL;
1423        }
1424
1425        cc->cipher_string = kstrdup(cipher_in, GFP_KERNEL);
1426        if (!cc->cipher_string)
1427                goto bad_mem;
1428
1429        /*
1430         * Legacy dm-crypt cipher specification
1431         * cipher[:keycount]-mode-iv:ivopts
1432         */
1433        tmp = cipher_in;
1434        keycount = strsep(&tmp, "-");
1435        cipher = strsep(&keycount, ":");
1436
1437        if (!keycount)
1438                cc->tfms_count = 1;
1439        else if (sscanf(keycount, "%u", &cc->tfms_count) != 1 ||
1440                 !is_power_of_2(cc->tfms_count)) {
1441                ti->error = "Bad cipher key count specification";
1442                return -EINVAL;
1443        }
1444        cc->key_parts = cc->tfms_count;
1445
1446        cc->cipher = kstrdup(cipher, GFP_KERNEL);
1447        if (!cc->cipher)
1448                goto bad_mem;
1449
1450        chainmode = strsep(&tmp, "-");
1451        ivopts = strsep(&tmp, "-");
1452        ivmode = strsep(&ivopts, ":");
1453
1454        if (tmp)
1455                DMWARN("Ignoring unexpected additional cipher options");
1456
1457        cc->cpu = __alloc_percpu(sizeof(*(cc->cpu)) +
1458                                 cc->tfms_count * sizeof(*(cc->cpu->tfms)),
1459                                 __alignof__(struct crypt_cpu));
1460        if (!cc->cpu) {
1461                ti->error = "Cannot allocate per cpu state";
1462                goto bad_mem;
1463        }
1464
1465        /*
1466         * For compatibility with the original dm-crypt mapping format, if
1467         * only the cipher name is supplied, use cbc-plain.
1468         */
1469        if (!chainmode || (!strcmp(chainmode, "plain") && !ivmode)) {
1470                chainmode = "cbc";
1471                ivmode = "plain";
1472        }
1473
1474        if (strcmp(chainmode, "ecb") && !ivmode) {
1475                ti->error = "IV mechanism required";
1476                return -EINVAL;
1477        }
1478
1479        cipher_api = kmalloc(CRYPTO_MAX_ALG_NAME, GFP_KERNEL);
1480        if (!cipher_api)
1481                goto bad_mem;
1482
1483        ret = snprintf(cipher_api, CRYPTO_MAX_ALG_NAME,
1484                       "%s(%s)", chainmode, cipher);
1485        if (ret < 0) {
1486                kfree(cipher_api);
1487                goto bad_mem;
1488        }
1489
1490        /* Allocate cipher */
1491        for_each_possible_cpu(cpu) {
1492                ret = crypt_alloc_tfms(cc, cpu, cipher_api);
1493                if (ret < 0) {
1494                        ti->error = "Error allocating crypto tfm";
1495                        goto bad;
1496                }
1497        }
1498
1499        /* Initialize and set key */
1500        ret = crypt_set_key(cc, key);
1501        if (ret < 0) {
1502                ti->error = "Error decoding and setting key";
1503                goto bad;
1504        }
1505
1506        /* Initialize IV */
1507        cc->iv_size = crypto_ablkcipher_ivsize(any_tfm(cc));
1508        if (cc->iv_size)
1509                /* at least a 64 bit sector number should fit in our buffer */
1510                cc->iv_size = max(cc->iv_size,
1511                                  (unsigned int)(sizeof(u64) / sizeof(u8)));
1512        else if (ivmode) {
1513                DMWARN("Selected cipher does not support IVs");
1514                ivmode = NULL;
1515        }
1516
1517        /* Choose ivmode, see comments at iv code. */
1518        if (ivmode == NULL)
1519                cc->iv_gen_ops = NULL;
1520        else if (strcmp(ivmode, "plain") == 0)
1521                cc->iv_gen_ops = &crypt_iv_plain_ops;
1522        else if (strcmp(ivmode, "plain64") == 0)
1523                cc->iv_gen_ops = &crypt_iv_plain64_ops;
1524        else if (strcmp(ivmode, "essiv") == 0)
1525                cc->iv_gen_ops = &crypt_iv_essiv_ops;
1526        else if (strcmp(ivmode, "benbi") == 0)
1527                cc->iv_gen_ops = &crypt_iv_benbi_ops;
1528        else if (strcmp(ivmode, "null") == 0)
1529                cc->iv_gen_ops = &crypt_iv_null_ops;
1530        else if (strcmp(ivmode, "lmk") == 0) {
1531                cc->iv_gen_ops = &crypt_iv_lmk_ops;
1532                /* Version 2 and 3 is recognised according
1533                 * to length of provided multi-key string.
1534                 * If present (version 3), last key is used as IV seed.
1535                 */
1536                if (cc->key_size % cc->key_parts)
1537                        cc->key_parts++;
1538        } else {
1539                ret = -EINVAL;
1540                ti->error = "Invalid IV mode";
1541                goto bad;
1542        }
1543
1544        /* Allocate IV */
1545        if (cc->iv_gen_ops && cc->iv_gen_ops->ctr) {
1546                ret = cc->iv_gen_ops->ctr(cc, ti, ivopts);
1547                if (ret < 0) {
1548                        ti->error = "Error creating IV";
1549                        goto bad;
1550                }
1551        }
1552
1553        /* Initialize IV (set keys for ESSIV etc) */
1554        if (cc->iv_gen_ops && cc->iv_gen_ops->init) {
1555                ret = cc->iv_gen_ops->init(cc);
1556                if (ret < 0) {
1557                        ti->error = "Error initialising IV";
1558                        goto bad;
1559                }
1560        }
1561
1562        ret = 0;
1563bad:
1564        kfree(cipher_api);
1565        return ret;
1566
1567bad_mem:
1568        ti->error = "Cannot allocate cipher strings";
1569        return -ENOMEM;
1570}
1571
1572/*
1573 * Construct an encryption mapping:
1574 * <cipher> <key> <iv_offset> <dev_path> <start>
1575 */
1576static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
1577{
1578        struct crypt_config *cc;
1579        unsigned int key_size, opt_params;
1580        unsigned long long tmpll;
1581        int ret;
1582        struct dm_arg_set as;
1583        const char *opt_string;
1584
1585        static struct dm_arg _args[] = {
1586                {0, 1, "Invalid number of feature args"},
1587        };
1588
1589        if (argc < 5) {
1590                ti->error = "Not enough arguments";
1591                return -EINVAL;
1592        }
1593
1594        key_size = strlen(argv[1]) >> 1;
1595
1596        cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
1597        if (!cc) {
1598                ti->error = "Cannot allocate encryption context";
1599                return -ENOMEM;
1600        }
1601        cc->key_size = key_size;
1602
1603        ti->private = cc;
1604        ret = crypt_ctr_cipher(ti, argv[0], argv[1]);
1605        if (ret < 0)
1606                goto bad;
1607
1608        ret = -ENOMEM;
1609        cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool);
1610        if (!cc->io_pool) {
1611                ti->error = "Cannot allocate crypt io mempool";
1612                goto bad;
1613        }
1614
1615        cc->dmreq_start = sizeof(struct ablkcipher_request);
1616        cc->dmreq_start += crypto_ablkcipher_reqsize(any_tfm(cc));
1617        cc->dmreq_start = ALIGN(cc->dmreq_start, crypto_tfm_ctx_alignment());
1618        cc->dmreq_start += crypto_ablkcipher_alignmask(any_tfm(cc)) &
1619                           ~(crypto_tfm_ctx_alignment() - 1);
1620
1621        cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start +
1622                        sizeof(struct dm_crypt_request) + cc->iv_size);
1623        if (!cc->req_pool) {
1624                ti->error = "Cannot allocate crypt request mempool";
1625                goto bad;
1626        }
1627
1628        cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0);
1629        if (!cc->page_pool) {
1630                ti->error = "Cannot allocate page mempool";
1631                goto bad;
1632        }
1633
1634        cc->bs = bioset_create(MIN_IOS, 0);
1635        if (!cc->bs) {
1636                ti->error = "Cannot allocate crypt bioset";
1637                goto bad;
1638        }
1639
1640        ret = -EINVAL;
1641        if (sscanf(argv[2], "%llu", &tmpll) != 1) {
1642                ti->error = "Invalid iv_offset sector";
1643                goto bad;
1644        }
1645        cc->iv_offset = tmpll;
1646
1647        if (dm_get_device(ti, argv[3], dm_table_get_mode(ti->table), &cc->dev)) {
1648                ti->error = "Device lookup failed";
1649                goto bad;
1650        }
1651
1652        if (sscanf(argv[4], "%llu", &tmpll) != 1) {
1653                ti->error = "Invalid device sector";
1654                goto bad;
1655        }
1656        cc->start = tmpll;
1657
1658        argv += 5;
1659        argc -= 5;
1660
1661        /* Optional parameters */
1662        if (argc) {
1663                as.argc = argc;
1664                as.argv = argv;
1665
1666                ret = dm_read_arg_group(_args, &as, &opt_params, &ti->error);
1667                if (ret)
1668                        goto bad;
1669
1670                opt_string = dm_shift_arg(&as);
1671
1672                if (opt_params == 1 && opt_string &&
1673                    !strcasecmp(opt_string, "allow_discards"))
1674                        ti->num_discard_requests = 1;
1675                else if (opt_params) {
1676                        ret = -EINVAL;
1677                        ti->error = "Invalid feature arguments";
1678                        goto bad;
1679                }
1680        }
1681
1682        ret = -ENOMEM;
1683        cc->io_queue = alloc_workqueue("kcryptd_io",
1684                                       WQ_NON_REENTRANT|
1685                                       WQ_MEM_RECLAIM,
1686                                       1);
1687        if (!cc->io_queue) {
1688                ti->error = "Couldn't create kcryptd io queue";
1689                goto bad;
1690        }
1691
1692        cc->crypt_queue = alloc_workqueue("kcryptd",
1693                                          WQ_NON_REENTRANT|
1694                                          WQ_CPU_INTENSIVE|
1695                                          WQ_MEM_RECLAIM,
1696                                          1);
1697        if (!cc->crypt_queue) {
1698                ti->error = "Couldn't create kcryptd queue";
1699                goto bad;
1700        }
1701
1702        ti->num_flush_requests = 1;
1703        ti->discard_zeroes_data_unsupported = 1;
1704
1705        return 0;
1706
1707bad:
1708        crypt_dtr(ti);
1709        return ret;
1710}
1711
1712static int crypt_map(struct dm_target *ti, struct bio *bio,
1713                     union map_info *map_context)
1714{
1715        struct dm_crypt_io *io;
1716        struct crypt_config *cc;
1717
1718        /*
1719         * If bio is REQ_FLUSH or REQ_DISCARD, just bypass crypt queues.
1720         * - for REQ_FLUSH device-mapper core ensures that no IO is in-flight
1721         * - for REQ_DISCARD caller must use flush if IO ordering matters
1722         */
1723        if (unlikely(bio->bi_rw & (REQ_FLUSH | REQ_DISCARD))) {
1724                cc = ti->private;
1725                bio->bi_bdev = cc->dev->bdev;
1726                if (bio_sectors(bio))
1727                        bio->bi_sector = cc->start + dm_target_offset(ti, bio->bi_sector);
1728                return DM_MAPIO_REMAPPED;
1729        }
1730
1731        io = crypt_io_alloc(ti, bio, dm_target_offset(ti, bio->bi_sector));
1732
1733        if (bio_data_dir(io->base_bio) == READ) {
1734                if (kcryptd_io_read(io, GFP_NOWAIT))
1735                        kcryptd_queue_io(io);
1736        } else
1737                kcryptd_queue_crypt(io);
1738
1739        return DM_MAPIO_SUBMITTED;
1740}
1741
1742static int crypt_status(struct dm_target *ti, status_type_t type,
1743                        char *result, unsigned int maxlen)
1744{
1745        struct crypt_config *cc = ti->private;
1746        unsigned int sz = 0;
1747
1748        switch (type) {
1749        case STATUSTYPE_INFO:
1750                result[0] = '\0';
1751                break;
1752
1753        case STATUSTYPE_TABLE:
1754                DMEMIT("%s ", cc->cipher_string);
1755
1756                if (cc->key_size > 0) {
1757                        if ((maxlen - sz) < ((cc->key_size << 1) + 1))
1758                                return -ENOMEM;
1759
1760                        crypt_encode_key(result + sz, cc->key, cc->key_size);
1761                        sz += cc->key_size << 1;
1762                } else {
1763                        if (sz >= maxlen)
1764                                return -ENOMEM;
1765                        result[sz++] = '-';
1766                }
1767
1768                DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset,
1769                                cc->dev->name, (unsigned long long)cc->start);
1770
1771                if (ti->num_discard_requests)
1772                        DMEMIT(" 1 allow_discards");
1773
1774                break;
1775        }
1776        return 0;
1777}
1778
1779static void crypt_postsuspend(struct dm_target *ti)
1780{
1781        struct crypt_config *cc = ti->private;
1782
1783        set_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1784}
1785
1786static int crypt_preresume(struct dm_target *ti)
1787{
1788        struct crypt_config *cc = ti->private;
1789
1790        if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) {
1791                DMERR("aborting resume - crypt key is not set.");
1792                return -EAGAIN;
1793        }
1794
1795        return 0;
1796}
1797
1798static void crypt_resume(struct dm_target *ti)
1799{
1800        struct crypt_config *cc = ti->private;
1801
1802        clear_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1803}
1804
1805/* Message interface
1806 *      key set <key>
1807 *      key wipe
1808 */
1809static int crypt_message(struct dm_target *ti, unsigned argc, char **argv)
1810{
1811        struct crypt_config *cc = ti->private;
1812        int ret = -EINVAL;
1813
1814        if (argc < 2)
1815                goto error;
1816
1817        if (!strcasecmp(argv[0], "key")) {
1818                if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) {
1819                        DMWARN("not suspended during key manipulation.");
1820                        return -EINVAL;
1821                }
1822                if (argc == 3 && !strcasecmp(argv[1], "set")) {
1823                        ret = crypt_set_key(cc, argv[2]);
1824                        if (ret)
1825                                return ret;
1826                        if (cc->iv_gen_ops && cc->iv_gen_ops->init)
1827                                ret = cc->iv_gen_ops->init(cc);
1828                        return ret;
1829                }
1830                if (argc == 2 && !strcasecmp(argv[1], "wipe")) {
1831                        if (cc->iv_gen_ops && cc->iv_gen_ops->wipe) {
1832                                ret = cc->iv_gen_ops->wipe(cc);
1833                                if (ret)
1834                                        return ret;
1835                        }
1836                        return crypt_wipe_key(cc);
1837                }
1838        }
1839
1840error:
1841        DMWARN("unrecognised message received.");
1842        return -EINVAL;
1843}
1844
1845static int crypt_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
1846                       struct bio_vec *biovec, int max_size)
1847{
1848        struct crypt_config *cc = ti->private;
1849        struct request_queue *q = bdev_get_queue(cc->dev->bdev);
1850
1851        if (!q->merge_bvec_fn)
1852                return max_size;
1853
1854        bvm->bi_bdev = cc->dev->bdev;
1855        bvm->bi_sector = cc->start + dm_target_offset(ti, bvm->bi_sector);
1856
1857        return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
1858}
1859
1860static int crypt_iterate_devices(struct dm_target *ti,
1861                                 iterate_devices_callout_fn fn, void *data)
1862{
1863        struct crypt_config *cc = ti->private;
1864
1865        return fn(ti, cc->dev, cc->start, ti->len, data);
1866}
1867
1868static struct target_type crypt_target = {
1869        .name   = "crypt",
1870        .version = {1, 11, 0},
1871        .module = THIS_MODULE,
1872        .ctr    = crypt_ctr,
1873        .dtr    = crypt_dtr,
1874        .map    = crypt_map,
1875        .status = crypt_status,
1876        .postsuspend = crypt_postsuspend,
1877        .preresume = crypt_preresume,
1878        .resume = crypt_resume,
1879        .message = crypt_message,
1880        .merge  = crypt_merge,
1881        .iterate_devices = crypt_iterate_devices,
1882};
1883
1884static int __init dm_crypt_init(void)
1885{
1886        int r;
1887
1888        _crypt_io_pool = KMEM_CACHE(dm_crypt_io, 0);
1889        if (!_crypt_io_pool)
1890                return -ENOMEM;
1891
1892        r = dm_register_target(&crypt_target);
1893        if (r < 0) {
1894                DMERR("register failed %d", r);
1895                kmem_cache_destroy(_crypt_io_pool);
1896        }
1897
1898        return r;
1899}
1900
1901static void __exit dm_crypt_exit(void)
1902{
1903        dm_unregister_target(&crypt_target);
1904        kmem_cache_destroy(_crypt_io_pool);
1905}
1906
1907module_init(dm_crypt_init);
1908module_exit(dm_crypt_exit);
1909
1910MODULE_AUTHOR("Christophe Saout <christophe@saout.de>");
1911MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption");
1912MODULE_LICENSE("GPL");
1913