linux/drivers/md/dm-crypt.c
<<
>>
Prefs
   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
 801static void dm_crypt_bio_destructor(struct bio *bio)
 802{
 803        struct dm_crypt_io *io = bio->bi_private;
 804        struct crypt_config *cc = io->cc;
 805
 806        bio_free(bio, cc->bs);
 807}
 808
 809/*
 810 * Generate a new unfragmented bio with the given size
 811 * This should never violate the device limitations
 812 * May return a smaller bio when running out of pages, indicated by
 813 * *out_of_pages set to 1.
 814 */
 815static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size,
 816                                      unsigned *out_of_pages)
 817{
 818        struct crypt_config *cc = io->cc;
 819        struct bio *clone;
 820        unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
 821        gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
 822        unsigned i, len;
 823        struct page *page;
 824
 825        clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs);
 826        if (!clone)
 827                return NULL;
 828
 829        clone_init(io, clone);
 830        *out_of_pages = 0;
 831
 832        for (i = 0; i < nr_iovecs; i++) {
 833                page = mempool_alloc(cc->page_pool, gfp_mask);
 834                if (!page) {
 835                        *out_of_pages = 1;
 836                        break;
 837                }
 838
 839                /*
 840                 * If additional pages cannot be allocated without waiting,
 841                 * return a partially-allocated bio.  The caller will then try
 842                 * to allocate more bios while submitting this partial bio.
 843                 */
 844                gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT;
 845
 846                len = (size > PAGE_SIZE) ? PAGE_SIZE : size;
 847
 848                if (!bio_add_page(clone, page, len, 0)) {
 849                        mempool_free(page, cc->page_pool);
 850                        break;
 851                }
 852
 853                size -= len;
 854        }
 855
 856        if (!clone->bi_size) {
 857                bio_put(clone);
 858                return NULL;
 859        }
 860
 861        return clone;
 862}
 863
 864static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone)
 865{
 866        unsigned int i;
 867        struct bio_vec *bv;
 868
 869        for (i = 0; i < clone->bi_vcnt; i++) {
 870                bv = bio_iovec_idx(clone, i);
 871                BUG_ON(!bv->bv_page);
 872                mempool_free(bv->bv_page, cc->page_pool);
 873                bv->bv_page = NULL;
 874        }
 875}
 876
 877static struct dm_crypt_io *crypt_io_alloc(struct crypt_config *cc,
 878                                          struct bio *bio, sector_t sector)
 879{
 880        struct dm_crypt_io *io;
 881
 882        io = mempool_alloc(cc->io_pool, GFP_NOIO);
 883        io->cc = cc;
 884        io->base_bio = bio;
 885        io->sector = sector;
 886        io->error = 0;
 887        io->base_io = NULL;
 888        atomic_set(&io->io_pending, 0);
 889
 890        return io;
 891}
 892
 893static void crypt_inc_pending(struct dm_crypt_io *io)
 894{
 895        atomic_inc(&io->io_pending);
 896}
 897
 898/*
 899 * One of the bios was finished. Check for completion of
 900 * the whole request and correctly clean up the buffer.
 901 * If base_io is set, wait for the last fragment to complete.
 902 */
 903static void crypt_dec_pending(struct dm_crypt_io *io)
 904{
 905        struct crypt_config *cc = io->cc;
 906        struct bio *base_bio = io->base_bio;
 907        struct dm_crypt_io *base_io = io->base_io;
 908        int error = io->error;
 909
 910        if (!atomic_dec_and_test(&io->io_pending))
 911                return;
 912
 913        mempool_free(io, cc->io_pool);
 914
 915        if (likely(!base_io))
 916                bio_endio(base_bio, error);
 917        else {
 918                if (error && !base_io->error)
 919                        base_io->error = error;
 920                crypt_dec_pending(base_io);
 921        }
 922}
 923
 924/*
 925 * kcryptd/kcryptd_io:
 926 *
 927 * Needed because it would be very unwise to do decryption in an
 928 * interrupt context.
 929 *
 930 * kcryptd performs the actual encryption or decryption.
 931 *
 932 * kcryptd_io performs the IO submission.
 933 *
 934 * They must be separated as otherwise the final stages could be
 935 * starved by new requests which can block in the first stages due
 936 * to memory allocation.
 937 *
 938 * The work is done per CPU global for all dm-crypt instances.
 939 * They should not depend on each other and do not block.
 940 */
 941static void crypt_endio(struct bio *clone, int error)
 942{
 943        struct dm_crypt_io *io = clone->bi_private;
 944        struct crypt_config *cc = io->cc;
 945        unsigned rw = bio_data_dir(clone);
 946
 947        if (unlikely(!bio_flagged(clone, BIO_UPTODATE) && !error))
 948                error = -EIO;
 949
 950        /*
 951         * free the processed pages
 952         */
 953        if (rw == WRITE)
 954                crypt_free_buffer_pages(cc, clone);
 955
 956        bio_put(clone);
 957
 958        if (rw == READ && !error) {
 959                kcryptd_queue_crypt(io);
 960                return;
 961        }
 962
 963        if (unlikely(error))
 964                io->error = error;
 965
 966        crypt_dec_pending(io);
 967}
 968
 969static void clone_init(struct dm_crypt_io *io, struct bio *clone)
 970{
 971        struct crypt_config *cc = io->cc;
 972
 973        clone->bi_private = io;
 974        clone->bi_end_io  = crypt_endio;
 975        clone->bi_bdev    = cc->dev->bdev;
 976        clone->bi_rw      = io->base_bio->bi_rw;
 977        clone->bi_destructor = dm_crypt_bio_destructor;
 978}
 979
 980static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp)
 981{
 982        struct crypt_config *cc = io->cc;
 983        struct bio *base_bio = io->base_bio;
 984        struct bio *clone;
 985
 986        /*
 987         * The block layer might modify the bvec array, so always
 988         * copy the required bvecs because we need the original
 989         * one in order to decrypt the whole bio data *afterwards*.
 990         */
 991        clone = bio_alloc_bioset(gfp, bio_segments(base_bio), cc->bs);
 992        if (!clone)
 993                return 1;
 994
 995        crypt_inc_pending(io);
 996
 997        clone_init(io, clone);
 998        clone->bi_idx = 0;
 999        clone->bi_vcnt = bio_segments(base_bio);
1000        clone->bi_size = base_bio->bi_size;
1001        clone->bi_sector = cc->start + io->sector;
1002        memcpy(clone->bi_io_vec, bio_iovec(base_bio),
1003               sizeof(struct bio_vec) * clone->bi_vcnt);
1004
1005        generic_make_request(clone);
1006        return 0;
1007}
1008
1009static void kcryptd_io_write(struct dm_crypt_io *io)
1010{
1011        struct bio *clone = io->ctx.bio_out;
1012        generic_make_request(clone);
1013}
1014
1015static void kcryptd_io(struct work_struct *work)
1016{
1017        struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
1018
1019        if (bio_data_dir(io->base_bio) == READ) {
1020                crypt_inc_pending(io);
1021                if (kcryptd_io_read(io, GFP_NOIO))
1022                        io->error = -ENOMEM;
1023                crypt_dec_pending(io);
1024        } else
1025                kcryptd_io_write(io);
1026}
1027
1028static void kcryptd_queue_io(struct dm_crypt_io *io)
1029{
1030        struct crypt_config *cc = io->cc;
1031
1032        INIT_WORK(&io->work, kcryptd_io);
1033        queue_work(cc->io_queue, &io->work);
1034}
1035
1036static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io, int async)
1037{
1038        struct bio *clone = io->ctx.bio_out;
1039        struct crypt_config *cc = io->cc;
1040
1041        if (unlikely(io->error < 0)) {
1042                crypt_free_buffer_pages(cc, clone);
1043                bio_put(clone);
1044                crypt_dec_pending(io);
1045                return;
1046        }
1047
1048        /* crypt_convert should have filled the clone bio */
1049        BUG_ON(io->ctx.idx_out < clone->bi_vcnt);
1050
1051        clone->bi_sector = cc->start + io->sector;
1052
1053        if (async)
1054                kcryptd_queue_io(io);
1055        else
1056                generic_make_request(clone);
1057}
1058
1059static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
1060{
1061        struct crypt_config *cc = io->cc;
1062        struct bio *clone;
1063        struct dm_crypt_io *new_io;
1064        int crypt_finished;
1065        unsigned out_of_pages = 0;
1066        unsigned remaining = io->base_bio->bi_size;
1067        sector_t sector = io->sector;
1068        int r;
1069
1070        /*
1071         * Prevent io from disappearing until this function completes.
1072         */
1073        crypt_inc_pending(io);
1074        crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, sector);
1075
1076        /*
1077         * The allocated buffers can be smaller than the whole bio,
1078         * so repeat the whole process until all the data can be handled.
1079         */
1080        while (remaining) {
1081                clone = crypt_alloc_buffer(io, remaining, &out_of_pages);
1082                if (unlikely(!clone)) {
1083                        io->error = -ENOMEM;
1084                        break;
1085                }
1086
1087                io->ctx.bio_out = clone;
1088                io->ctx.idx_out = 0;
1089
1090                remaining -= clone->bi_size;
1091                sector += bio_sectors(clone);
1092
1093                crypt_inc_pending(io);
1094
1095                r = crypt_convert(cc, &io->ctx);
1096                if (r < 0)
1097                        io->error = -EIO;
1098
1099                crypt_finished = atomic_dec_and_test(&io->ctx.cc_pending);
1100
1101                /* Encryption was already finished, submit io now */
1102                if (crypt_finished) {
1103                        kcryptd_crypt_write_io_submit(io, 0);
1104
1105                        /*
1106                         * If there was an error, do not try next fragments.
1107                         * For async, error is processed in async handler.
1108                         */
1109                        if (unlikely(r < 0))
1110                                break;
1111
1112                        io->sector = sector;
1113                }
1114
1115                /*
1116                 * Out of memory -> run queues
1117                 * But don't wait if split was due to the io size restriction
1118                 */
1119                if (unlikely(out_of_pages))
1120                        congestion_wait(BLK_RW_ASYNC, HZ/100);
1121
1122                /*
1123                 * With async crypto it is unsafe to share the crypto context
1124                 * between fragments, so switch to a new dm_crypt_io structure.
1125                 */
1126                if (unlikely(!crypt_finished && remaining)) {
1127                        new_io = crypt_io_alloc(io->cc, io->base_bio,
1128                                                sector);
1129                        crypt_inc_pending(new_io);
1130                        crypt_convert_init(cc, &new_io->ctx, NULL,
1131                                           io->base_bio, sector);
1132                        new_io->ctx.idx_in = io->ctx.idx_in;
1133                        new_io->ctx.offset_in = io->ctx.offset_in;
1134
1135                        /*
1136                         * Fragments after the first use the base_io
1137                         * pending count.
1138                         */
1139                        if (!io->base_io)
1140                                new_io->base_io = io;
1141                        else {
1142                                new_io->base_io = io->base_io;
1143                                crypt_inc_pending(io->base_io);
1144                                crypt_dec_pending(io);
1145                        }
1146
1147                        io = new_io;
1148                }
1149        }
1150
1151        crypt_dec_pending(io);
1152}
1153
1154static void kcryptd_crypt_read_done(struct dm_crypt_io *io)
1155{
1156        crypt_dec_pending(io);
1157}
1158
1159static void kcryptd_crypt_read_convert(struct dm_crypt_io *io)
1160{
1161        struct crypt_config *cc = io->cc;
1162        int r = 0;
1163
1164        crypt_inc_pending(io);
1165
1166        crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio,
1167                           io->sector);
1168
1169        r = crypt_convert(cc, &io->ctx);
1170        if (r < 0)
1171                io->error = -EIO;
1172
1173        if (atomic_dec_and_test(&io->ctx.cc_pending))
1174                kcryptd_crypt_read_done(io);
1175
1176        crypt_dec_pending(io);
1177}
1178
1179static void kcryptd_async_done(struct crypto_async_request *async_req,
1180                               int error)
1181{
1182        struct dm_crypt_request *dmreq = async_req->data;
1183        struct convert_context *ctx = dmreq->ctx;
1184        struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx);
1185        struct crypt_config *cc = io->cc;
1186
1187        if (error == -EINPROGRESS) {
1188                complete(&ctx->restart);
1189                return;
1190        }
1191
1192        if (!error && cc->iv_gen_ops && cc->iv_gen_ops->post)
1193                error = cc->iv_gen_ops->post(cc, iv_of_dmreq(cc, dmreq), dmreq);
1194
1195        if (error < 0)
1196                io->error = -EIO;
1197
1198        mempool_free(req_of_dmreq(cc, dmreq), cc->req_pool);
1199
1200        if (!atomic_dec_and_test(&ctx->cc_pending))
1201                return;
1202
1203        if (bio_data_dir(io->base_bio) == READ)
1204                kcryptd_crypt_read_done(io);
1205        else
1206                kcryptd_crypt_write_io_submit(io, 1);
1207}
1208
1209static void kcryptd_crypt(struct work_struct *work)
1210{
1211        struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
1212
1213        if (bio_data_dir(io->base_bio) == READ)
1214                kcryptd_crypt_read_convert(io);
1215        else
1216                kcryptd_crypt_write_convert(io);
1217}
1218
1219static void kcryptd_queue_crypt(struct dm_crypt_io *io)
1220{
1221        struct crypt_config *cc = io->cc;
1222
1223        INIT_WORK(&io->work, kcryptd_crypt);
1224        queue_work(cc->crypt_queue, &io->work);
1225}
1226
1227/*
1228 * Decode key from its hex representation
1229 */
1230static int crypt_decode_key(u8 *key, char *hex, unsigned int size)
1231{
1232        char buffer[3];
1233        unsigned int i;
1234
1235        buffer[2] = '\0';
1236
1237        for (i = 0; i < size; i++) {
1238                buffer[0] = *hex++;
1239                buffer[1] = *hex++;
1240
1241                if (kstrtou8(buffer, 16, &key[i]))
1242                        return -EINVAL;
1243        }
1244
1245        if (*hex != '\0')
1246                return -EINVAL;
1247
1248        return 0;
1249}
1250
1251/*
1252 * Encode key into its hex representation
1253 */
1254static void crypt_encode_key(char *hex, u8 *key, unsigned int size)
1255{
1256        unsigned int i;
1257
1258        for (i = 0; i < size; i++) {
1259                sprintf(hex, "%02x", *key);
1260                hex += 2;
1261                key++;
1262        }
1263}
1264
1265static void crypt_free_tfms(struct crypt_config *cc)
1266{
1267        unsigned i;
1268
1269        if (!cc->tfms)
1270                return;
1271
1272        for (i = 0; i < cc->tfms_count; i++)
1273                if (cc->tfms[i] && !IS_ERR(cc->tfms[i])) {
1274                        crypto_free_ablkcipher(cc->tfms[i]);
1275                        cc->tfms[i] = NULL;
1276                }
1277
1278        kfree(cc->tfms);
1279        cc->tfms = NULL;
1280}
1281
1282static int crypt_alloc_tfms(struct crypt_config *cc, char *ciphermode)
1283{
1284        unsigned i;
1285        int err;
1286
1287        cc->tfms = kmalloc(cc->tfms_count * sizeof(struct crypto_ablkcipher *),
1288                           GFP_KERNEL);
1289        if (!cc->tfms)
1290                return -ENOMEM;
1291
1292        for (i = 0; i < cc->tfms_count; i++) {
1293                cc->tfms[i] = crypto_alloc_ablkcipher(ciphermode, 0, 0);
1294                if (IS_ERR(cc->tfms[i])) {
1295                        err = PTR_ERR(cc->tfms[i]);
1296                        crypt_free_tfms(cc);
1297                        return err;
1298                }
1299        }
1300
1301        return 0;
1302}
1303
1304static int crypt_setkey_allcpus(struct crypt_config *cc)
1305{
1306        unsigned subkey_size = cc->key_size >> ilog2(cc->tfms_count);
1307        int err = 0, i, r;
1308
1309        for (i = 0; i < cc->tfms_count; i++) {
1310                r = crypto_ablkcipher_setkey(cc->tfms[i],
1311                                             cc->key + (i * subkey_size),
1312                                             subkey_size);
1313                if (r)
1314                        err = r;
1315        }
1316
1317        return err;
1318}
1319
1320static int crypt_set_key(struct crypt_config *cc, char *key)
1321{
1322        int r = -EINVAL;
1323        int key_string_len = strlen(key);
1324
1325        /* The key size may not be changed. */
1326        if (cc->key_size != (key_string_len >> 1))
1327                goto out;
1328
1329        /* Hyphen (which gives a key_size of zero) means there is no key. */
1330        if (!cc->key_size && strcmp(key, "-"))
1331                goto out;
1332
1333        if (cc->key_size && crypt_decode_key(cc->key, key, cc->key_size) < 0)
1334                goto out;
1335
1336        set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
1337
1338        r = crypt_setkey_allcpus(cc);
1339
1340out:
1341        /* Hex key string not needed after here, so wipe it. */
1342        memset(key, '0', key_string_len);
1343
1344        return r;
1345}
1346
1347static int crypt_wipe_key(struct crypt_config *cc)
1348{
1349        clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
1350        memset(&cc->key, 0, cc->key_size * sizeof(u8));
1351
1352        return crypt_setkey_allcpus(cc);
1353}
1354
1355static void crypt_dtr(struct dm_target *ti)
1356{
1357        struct crypt_config *cc = ti->private;
1358        struct crypt_cpu *cpu_cc;
1359        int cpu;
1360
1361        ti->private = NULL;
1362
1363        if (!cc)
1364                return;
1365
1366        if (cc->io_queue)
1367                destroy_workqueue(cc->io_queue);
1368        if (cc->crypt_queue)
1369                destroy_workqueue(cc->crypt_queue);
1370
1371        if (cc->cpu)
1372                for_each_possible_cpu(cpu) {
1373                        cpu_cc = per_cpu_ptr(cc->cpu, cpu);
1374                        if (cpu_cc->req)
1375                                mempool_free(cpu_cc->req, cc->req_pool);
1376                }
1377
1378        crypt_free_tfms(cc);
1379
1380        if (cc->bs)
1381                bioset_free(cc->bs);
1382
1383        if (cc->page_pool)
1384                mempool_destroy(cc->page_pool);
1385        if (cc->req_pool)
1386                mempool_destroy(cc->req_pool);
1387        if (cc->io_pool)
1388                mempool_destroy(cc->io_pool);
1389
1390        if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
1391                cc->iv_gen_ops->dtr(cc);
1392
1393        if (cc->dev)
1394                dm_put_device(ti, cc->dev);
1395
1396        if (cc->cpu)
1397                free_percpu(cc->cpu);
1398
1399        kzfree(cc->cipher);
1400        kzfree(cc->cipher_string);
1401
1402        /* Must zero key material before freeing */
1403        kzfree(cc);
1404}
1405
1406static int crypt_ctr_cipher(struct dm_target *ti,
1407                            char *cipher_in, char *key)
1408{
1409        struct crypt_config *cc = ti->private;
1410        char *tmp, *cipher, *chainmode, *ivmode, *ivopts, *keycount;
1411        char *cipher_api = NULL;
1412        int ret = -EINVAL;
1413        char dummy;
1414
1415        /* Convert to crypto api definition? */
1416        if (strchr(cipher_in, '(')) {
1417                ti->error = "Bad cipher specification";
1418                return -EINVAL;
1419        }
1420
1421        cc->cipher_string = kstrdup(cipher_in, GFP_KERNEL);
1422        if (!cc->cipher_string)
1423                goto bad_mem;
1424
1425        /*
1426         * Legacy dm-crypt cipher specification
1427         * cipher[:keycount]-mode-iv:ivopts
1428         */
1429        tmp = cipher_in;
1430        keycount = strsep(&tmp, "-");
1431        cipher = strsep(&keycount, ":");
1432
1433        if (!keycount)
1434                cc->tfms_count = 1;
1435        else if (sscanf(keycount, "%u%c", &cc->tfms_count, &dummy) != 1 ||
1436                 !is_power_of_2(cc->tfms_count)) {
1437                ti->error = "Bad cipher key count specification";
1438                return -EINVAL;
1439        }
1440        cc->key_parts = cc->tfms_count;
1441
1442        cc->cipher = kstrdup(cipher, GFP_KERNEL);
1443        if (!cc->cipher)
1444                goto bad_mem;
1445
1446        chainmode = strsep(&tmp, "-");
1447        ivopts = strsep(&tmp, "-");
1448        ivmode = strsep(&ivopts, ":");
1449
1450        if (tmp)
1451                DMWARN("Ignoring unexpected additional cipher options");
1452
1453        cc->cpu = __alloc_percpu(sizeof(*(cc->cpu)),
1454                                 __alignof__(struct crypt_cpu));
1455        if (!cc->cpu) {
1456                ti->error = "Cannot allocate per cpu state";
1457                goto bad_mem;
1458        }
1459
1460        /*
1461         * For compatibility with the original dm-crypt mapping format, if
1462         * only the cipher name is supplied, use cbc-plain.
1463         */
1464        if (!chainmode || (!strcmp(chainmode, "plain") && !ivmode)) {
1465                chainmode = "cbc";
1466                ivmode = "plain";
1467        }
1468
1469        if (strcmp(chainmode, "ecb") && !ivmode) {
1470                ti->error = "IV mechanism required";
1471                return -EINVAL;
1472        }
1473
1474        cipher_api = kmalloc(CRYPTO_MAX_ALG_NAME, GFP_KERNEL);
1475        if (!cipher_api)
1476                goto bad_mem;
1477
1478        ret = snprintf(cipher_api, CRYPTO_MAX_ALG_NAME,
1479                       "%s(%s)", chainmode, cipher);
1480        if (ret < 0) {
1481                kfree(cipher_api);
1482                goto bad_mem;
1483        }
1484
1485        /* Allocate cipher */
1486        ret = crypt_alloc_tfms(cc, cipher_api);
1487        if (ret < 0) {
1488                ti->error = "Error allocating crypto tfm";
1489                goto bad;
1490        }
1491
1492        /* Initialize and set key */
1493        ret = crypt_set_key(cc, key);
1494        if (ret < 0) {
1495                ti->error = "Error decoding and setting key";
1496                goto bad;
1497        }
1498
1499        /* Initialize IV */
1500        cc->iv_size = crypto_ablkcipher_ivsize(any_tfm(cc));
1501        if (cc->iv_size)
1502                /* at least a 64 bit sector number should fit in our buffer */
1503                cc->iv_size = max(cc->iv_size,
1504                                  (unsigned int)(sizeof(u64) / sizeof(u8)));
1505        else if (ivmode) {
1506                DMWARN("Selected cipher does not support IVs");
1507                ivmode = NULL;
1508        }
1509
1510        /* Choose ivmode, see comments at iv code. */
1511        if (ivmode == NULL)
1512                cc->iv_gen_ops = NULL;
1513        else if (strcmp(ivmode, "plain") == 0)
1514                cc->iv_gen_ops = &crypt_iv_plain_ops;
1515        else if (strcmp(ivmode, "plain64") == 0)
1516                cc->iv_gen_ops = &crypt_iv_plain64_ops;
1517        else if (strcmp(ivmode, "essiv") == 0)
1518                cc->iv_gen_ops = &crypt_iv_essiv_ops;
1519        else if (strcmp(ivmode, "benbi") == 0)
1520                cc->iv_gen_ops = &crypt_iv_benbi_ops;
1521        else if (strcmp(ivmode, "null") == 0)
1522                cc->iv_gen_ops = &crypt_iv_null_ops;
1523        else if (strcmp(ivmode, "lmk") == 0) {
1524                cc->iv_gen_ops = &crypt_iv_lmk_ops;
1525                /* Version 2 and 3 is recognised according
1526                 * to length of provided multi-key string.
1527                 * If present (version 3), last key is used as IV seed.
1528                 */
1529                if (cc->key_size % cc->key_parts)
1530                        cc->key_parts++;
1531        } else {
1532                ret = -EINVAL;
1533                ti->error = "Invalid IV mode";
1534                goto bad;
1535        }
1536
1537        /* Allocate IV */
1538        if (cc->iv_gen_ops && cc->iv_gen_ops->ctr) {
1539                ret = cc->iv_gen_ops->ctr(cc, ti, ivopts);
1540                if (ret < 0) {
1541                        ti->error = "Error creating IV";
1542                        goto bad;
1543                }
1544        }
1545
1546        /* Initialize IV (set keys for ESSIV etc) */
1547        if (cc->iv_gen_ops && cc->iv_gen_ops->init) {
1548                ret = cc->iv_gen_ops->init(cc);
1549                if (ret < 0) {
1550                        ti->error = "Error initialising IV";
1551                        goto bad;
1552                }
1553        }
1554
1555        ret = 0;
1556bad:
1557        kfree(cipher_api);
1558        return ret;
1559
1560bad_mem:
1561        ti->error = "Cannot allocate cipher strings";
1562        return -ENOMEM;
1563}
1564
1565/*
1566 * Construct an encryption mapping:
1567 * <cipher> <key> <iv_offset> <dev_path> <start>
1568 */
1569static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
1570{
1571        struct crypt_config *cc;
1572        unsigned int key_size, opt_params;
1573        unsigned long long tmpll;
1574        int ret;
1575        struct dm_arg_set as;
1576        const char *opt_string;
1577        char dummy;
1578
1579        static struct dm_arg _args[] = {
1580                {0, 1, "Invalid number of feature args"},
1581        };
1582
1583        if (argc < 5) {
1584                ti->error = "Not enough arguments";
1585                return -EINVAL;
1586        }
1587
1588        key_size = strlen(argv[1]) >> 1;
1589
1590        cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
1591        if (!cc) {
1592                ti->error = "Cannot allocate encryption context";
1593                return -ENOMEM;
1594        }
1595        cc->key_size = key_size;
1596
1597        ti->private = cc;
1598        ret = crypt_ctr_cipher(ti, argv[0], argv[1]);
1599        if (ret < 0)
1600                goto bad;
1601
1602        ret = -ENOMEM;
1603        cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool);
1604        if (!cc->io_pool) {
1605                ti->error = "Cannot allocate crypt io mempool";
1606                goto bad;
1607        }
1608
1609        cc->dmreq_start = sizeof(struct ablkcipher_request);
1610        cc->dmreq_start += crypto_ablkcipher_reqsize(any_tfm(cc));
1611        cc->dmreq_start = ALIGN(cc->dmreq_start, crypto_tfm_ctx_alignment());
1612        cc->dmreq_start += crypto_ablkcipher_alignmask(any_tfm(cc)) &
1613                           ~(crypto_tfm_ctx_alignment() - 1);
1614
1615        cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start +
1616                        sizeof(struct dm_crypt_request) + cc->iv_size);
1617        if (!cc->req_pool) {
1618                ti->error = "Cannot allocate crypt request mempool";
1619                goto bad;
1620        }
1621
1622        cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0);
1623        if (!cc->page_pool) {
1624                ti->error = "Cannot allocate page mempool";
1625                goto bad;
1626        }
1627
1628        cc->bs = bioset_create(MIN_IOS, 0);
1629        if (!cc->bs) {
1630                ti->error = "Cannot allocate crypt bioset";
1631                goto bad;
1632        }
1633
1634        ret = -EINVAL;
1635        if (sscanf(argv[2], "%llu%c", &tmpll, &dummy) != 1) {
1636                ti->error = "Invalid iv_offset sector";
1637                goto bad;
1638        }
1639        cc->iv_offset = tmpll;
1640
1641        if (dm_get_device(ti, argv[3], dm_table_get_mode(ti->table), &cc->dev)) {
1642                ti->error = "Device lookup failed";
1643                goto bad;
1644        }
1645
1646        if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1) {
1647                ti->error = "Invalid device sector";
1648                goto bad;
1649        }
1650        cc->start = tmpll;
1651
1652        argv += 5;
1653        argc -= 5;
1654
1655        /* Optional parameters */
1656        if (argc) {
1657                as.argc = argc;
1658                as.argv = argv;
1659
1660                ret = dm_read_arg_group(_args, &as, &opt_params, &ti->error);
1661                if (ret)
1662                        goto bad;
1663
1664                opt_string = dm_shift_arg(&as);
1665
1666                if (opt_params == 1 && opt_string &&
1667                    !strcasecmp(opt_string, "allow_discards"))
1668                        ti->num_discard_requests = 1;
1669                else if (opt_params) {
1670                        ret = -EINVAL;
1671                        ti->error = "Invalid feature arguments";
1672                        goto bad;
1673                }
1674        }
1675
1676        ret = -ENOMEM;
1677        cc->io_queue = alloc_workqueue("kcryptd_io",
1678                                       WQ_NON_REENTRANT|
1679                                       WQ_MEM_RECLAIM,
1680                                       1);
1681        if (!cc->io_queue) {
1682                ti->error = "Couldn't create kcryptd io queue";
1683                goto bad;
1684        }
1685
1686        cc->crypt_queue = alloc_workqueue("kcryptd",
1687                                          WQ_NON_REENTRANT|
1688                                          WQ_CPU_INTENSIVE|
1689                                          WQ_MEM_RECLAIM,
1690                                          1);
1691        if (!cc->crypt_queue) {
1692                ti->error = "Couldn't create kcryptd queue";
1693                goto bad;
1694        }
1695
1696        ti->num_flush_requests = 1;
1697        ti->discard_zeroes_data_unsupported = true;
1698
1699        return 0;
1700
1701bad:
1702        crypt_dtr(ti);
1703        return ret;
1704}
1705
1706static int crypt_map(struct dm_target *ti, struct bio *bio,
1707                     union map_info *map_context)
1708{
1709        struct dm_crypt_io *io;
1710        struct crypt_config *cc = ti->private;
1711
1712        /*
1713         * If bio is REQ_FLUSH or REQ_DISCARD, just bypass crypt queues.
1714         * - for REQ_FLUSH device-mapper core ensures that no IO is in-flight
1715         * - for REQ_DISCARD caller must use flush if IO ordering matters
1716         */
1717        if (unlikely(bio->bi_rw & (REQ_FLUSH | REQ_DISCARD))) {
1718                bio->bi_bdev = cc->dev->bdev;
1719                if (bio_sectors(bio))
1720                        bio->bi_sector = cc->start + dm_target_offset(ti, bio->bi_sector);
1721                return DM_MAPIO_REMAPPED;
1722        }
1723
1724        io = crypt_io_alloc(cc, bio, dm_target_offset(ti, bio->bi_sector));
1725
1726        if (bio_data_dir(io->base_bio) == READ) {
1727                if (kcryptd_io_read(io, GFP_NOWAIT))
1728                        kcryptd_queue_io(io);
1729        } else
1730                kcryptd_queue_crypt(io);
1731
1732        return DM_MAPIO_SUBMITTED;
1733}
1734
1735static int crypt_status(struct dm_target *ti, status_type_t type,
1736                        unsigned status_flags, char *result, unsigned maxlen)
1737{
1738        struct crypt_config *cc = ti->private;
1739        unsigned int sz = 0;
1740
1741        switch (type) {
1742        case STATUSTYPE_INFO:
1743                result[0] = '\0';
1744                break;
1745
1746        case STATUSTYPE_TABLE:
1747                DMEMIT("%s ", cc->cipher_string);
1748
1749                if (cc->key_size > 0) {
1750                        if ((maxlen - sz) < ((cc->key_size << 1) + 1))
1751                                return -ENOMEM;
1752
1753                        crypt_encode_key(result + sz, cc->key, cc->key_size);
1754                        sz += cc->key_size << 1;
1755                } else {
1756                        if (sz >= maxlen)
1757                                return -ENOMEM;
1758                        result[sz++] = '-';
1759                }
1760
1761                DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset,
1762                                cc->dev->name, (unsigned long long)cc->start);
1763
1764                if (ti->num_discard_requests)
1765                        DMEMIT(" 1 allow_discards");
1766
1767                break;
1768        }
1769        return 0;
1770}
1771
1772static void crypt_postsuspend(struct dm_target *ti)
1773{
1774        struct crypt_config *cc = ti->private;
1775
1776        set_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1777}
1778
1779static int crypt_preresume(struct dm_target *ti)
1780{
1781        struct crypt_config *cc = ti->private;
1782
1783        if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) {
1784                DMERR("aborting resume - crypt key is not set.");
1785                return -EAGAIN;
1786        }
1787
1788        return 0;
1789}
1790
1791static void crypt_resume(struct dm_target *ti)
1792{
1793        struct crypt_config *cc = ti->private;
1794
1795        clear_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1796}
1797
1798/* Message interface
1799 *      key set <key>
1800 *      key wipe
1801 */
1802static int crypt_message(struct dm_target *ti, unsigned argc, char **argv)
1803{
1804        struct crypt_config *cc = ti->private;
1805        int ret = -EINVAL;
1806
1807        if (argc < 2)
1808                goto error;
1809
1810        if (!strcasecmp(argv[0], "key")) {
1811                if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) {
1812                        DMWARN("not suspended during key manipulation.");
1813                        return -EINVAL;
1814                }
1815                if (argc == 3 && !strcasecmp(argv[1], "set")) {
1816                        ret = crypt_set_key(cc, argv[2]);
1817                        if (ret)
1818                                return ret;
1819                        if (cc->iv_gen_ops && cc->iv_gen_ops->init)
1820                                ret = cc->iv_gen_ops->init(cc);
1821                        return ret;
1822                }
1823                if (argc == 2 && !strcasecmp(argv[1], "wipe")) {
1824                        if (cc->iv_gen_ops && cc->iv_gen_ops->wipe) {
1825                                ret = cc->iv_gen_ops->wipe(cc);
1826                                if (ret)
1827                                        return ret;
1828                        }
1829                        return crypt_wipe_key(cc);
1830                }
1831        }
1832
1833error:
1834        DMWARN("unrecognised message received.");
1835        return -EINVAL;
1836}
1837
1838static int crypt_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
1839                       struct bio_vec *biovec, int max_size)
1840{
1841        struct crypt_config *cc = ti->private;
1842        struct request_queue *q = bdev_get_queue(cc->dev->bdev);
1843
1844        if (!q->merge_bvec_fn)
1845                return max_size;
1846
1847        bvm->bi_bdev = cc->dev->bdev;
1848        bvm->bi_sector = cc->start + dm_target_offset(ti, bvm->bi_sector);
1849
1850        return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
1851}
1852
1853static int crypt_iterate_devices(struct dm_target *ti,
1854                                 iterate_devices_callout_fn fn, void *data)
1855{
1856        struct crypt_config *cc = ti->private;
1857
1858        return fn(ti, cc->dev, cc->start, ti->len, data);
1859}
1860
1861static struct target_type crypt_target = {
1862        .name   = "crypt",
1863        .version = {1, 11, 0},
1864        .module = THIS_MODULE,
1865        .ctr    = crypt_ctr,
1866        .dtr    = crypt_dtr,
1867        .map    = crypt_map,
1868        .status = crypt_status,
1869        .postsuspend = crypt_postsuspend,
1870        .preresume = crypt_preresume,
1871        .resume = crypt_resume,
1872        .message = crypt_message,
1873        .merge  = crypt_merge,
1874        .iterate_devices = crypt_iterate_devices,
1875};
1876
1877static int __init dm_crypt_init(void)
1878{
1879        int r;
1880
1881        _crypt_io_pool = KMEM_CACHE(dm_crypt_io, 0);
1882        if (!_crypt_io_pool)
1883                return -ENOMEM;
1884
1885        r = dm_register_target(&crypt_target);
1886        if (r < 0) {
1887                DMERR("register failed %d", r);
1888                kmem_cache_destroy(_crypt_io_pool);
1889        }
1890
1891        return r;
1892}
1893
1894static void __exit dm_crypt_exit(void)
1895{
1896        dm_unregister_target(&crypt_target);
1897        kmem_cache_destroy(_crypt_io_pool);
1898}
1899
1900module_init(dm_crypt_init);
1901module_exit(dm_crypt_exit);
1902
1903MODULE_AUTHOR("Christophe Saout <christophe@saout.de>");
1904MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption");
1905MODULE_LICENSE("GPL");
1906
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.