Root/drivers/md/dm-crypt.c

1/*
2 * Copyright (C) 2003 Christophe Saout <christophe@saout.de>
3 * Copyright (C) 2004 Clemens Fruhwirth <clemens@endorphin.org>
4 * Copyright (C) 2006-2009 Red Hat, Inc. All rights reserved.
5 *
6 * This file is released under the GPL.
7 */
8
9#include <linux/completion.h>
10#include <linux/err.h>
11#include <linux/module.h>
12#include <linux/init.h>
13#include <linux/kernel.h>
14#include <linux/bio.h>
15#include <linux/blkdev.h>
16#include <linux/mempool.h>
17#include <linux/slab.h>
18#include <linux/crypto.h>
19#include <linux/workqueue.h>
20#include <linux/backing-dev.h>
21#include <linux/percpu.h>
22#include <linux/atomic.h>
23#include <linux/scatterlist.h>
24#include <asm/page.h>
25#include <asm/unaligned.h>
26#include <crypto/hash.h>
27#include <crypto/md5.h>
28#include <crypto/algapi.h>
29
30#include <linux/device-mapper.h>
31
32#define DM_MSG_PREFIX "crypt"
33
34/*
35 * context holding the current state of a multi-part conversion
36 */
37struct convert_context {
38    struct completion restart;
39    struct bio *bio_in;
40    struct bio *bio_out;
41    unsigned int offset_in;
42    unsigned int offset_out;
43    unsigned int idx_in;
44    unsigned int idx_out;
45    sector_t cc_sector;
46    atomic_t cc_pending;
47};
48
49/*
50 * per bio private data
51 */
52struct dm_crypt_io {
53    struct crypt_config *cc;
54    struct bio *base_bio;
55    struct work_struct work;
56
57    struct convert_context ctx;
58
59    atomic_t io_pending;
60    int error;
61    sector_t sector;
62    struct dm_crypt_io *base_io;
63};
64
65struct dm_crypt_request {
66    struct convert_context *ctx;
67    struct scatterlist sg_in;
68    struct scatterlist sg_out;
69    sector_t iv_sector;
70};
71
72struct crypt_config;
73
74struct crypt_iv_operations {
75    int (*ctr)(struct crypt_config *cc, struct dm_target *ti,
76           const char *opts);
77    void (*dtr)(struct crypt_config *cc);
78    int (*init)(struct crypt_config *cc);
79    int (*wipe)(struct crypt_config *cc);
80    int (*generator)(struct crypt_config *cc, u8 *iv,
81             struct dm_crypt_request *dmreq);
82    int (*post)(struct crypt_config *cc, u8 *iv,
83            struct dm_crypt_request *dmreq);
84};
85
86struct iv_essiv_private {
87    struct crypto_hash *hash_tfm;
88    u8 *salt;
89};
90
91struct iv_benbi_private {
92    int shift;
93};
94
95#define LMK_SEED_SIZE 64 /* hash + 0 */
96struct iv_lmk_private {
97    struct crypto_shash *hash_tfm;
98    u8 *seed;
99};
100
101/*
102 * Crypt: maps a linear range of a block device
103 * and encrypts / decrypts at the same time.
104 */
105enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID };
106
107/*
108 * Duplicated per-CPU state for cipher.
109 */
110struct crypt_cpu {
111    struct ablkcipher_request *req;
112};
113
114/*
115 * The fields in here must be read only after initialization,
116 * changing state should be in crypt_cpu.
117 */
118struct crypt_config {
119    struct dm_dev *dev;
120    sector_t start;
121
122    /*
123     * pool for per bio private data, crypto requests and
124     * encryption requeusts/buffer pages
125     */
126    mempool_t *io_pool;
127    mempool_t *req_pool;
128    mempool_t *page_pool;
129    struct bio_set *bs;
130
131    struct workqueue_struct *io_queue;
132    struct workqueue_struct *crypt_queue;
133
134    char *cipher;
135    char *cipher_string;
136
137    struct crypt_iv_operations *iv_gen_ops;
138    union {
139        struct iv_essiv_private essiv;
140        struct iv_benbi_private benbi;
141        struct iv_lmk_private lmk;
142    } iv_gen_private;
143    sector_t iv_offset;
144    unsigned int iv_size;
145
146    /*
147     * Duplicated per cpu state. Access through
148     * per_cpu_ptr() only.
149     */
150    struct crypt_cpu __percpu *cpu;
151
152    /* ESSIV: struct crypto_cipher *essiv_tfm */
153    void *iv_private;
154    struct crypto_ablkcipher **tfms;
155    unsigned tfms_count;
156
157    /*
158     * Layout of each crypto request:
159     *
160     * struct ablkcipher_request
161     * context
162     * padding
163     * struct dm_crypt_request
164     * padding
165     * IV
166     *
167     * The padding is added so that dm_crypt_request and the IV are
168     * correctly aligned.
169     */
170    unsigned int dmreq_start;
171
172    unsigned long flags;
173    unsigned int key_size;
174    unsigned int key_parts;
175    u8 key[0];
176};
177
178#define MIN_IOS 16
179#define MIN_POOL_PAGES 32
180
181static struct kmem_cache *_crypt_io_pool;
182
183static void clone_init(struct dm_crypt_io *, struct bio *);
184static void kcryptd_queue_crypt(struct dm_crypt_io *io);
185static u8 *iv_of_dmreq(struct crypt_config *cc, struct dm_crypt_request *dmreq);
186
187static struct crypt_cpu *this_crypt_config(struct crypt_config *cc)
188{
189    return this_cpu_ptr(cc->cpu);
190}
191
192/*
193 * Use this to access cipher attributes that are the same for each CPU.
194 */
195static struct crypto_ablkcipher *any_tfm(struct crypt_config *cc)
196{
197    return cc->tfms[0];
198}
199
200/*
201 * Different IV generation algorithms:
202 *
203 * plain: the initial vector is the 32-bit little-endian version of the sector
204 * number, padded with zeros if necessary.
205 *
206 * plain64: the initial vector is the 64-bit little-endian version of the sector
207 * number, padded with zeros if necessary.
208 *
209 * essiv: "encrypted sector|salt initial vector", the sector number is
210 * encrypted with the bulk cipher using a salt as key. The salt
211 * should be derived from the bulk cipher's key via hashing.
212 *
213 * benbi: the 64-bit "big-endian 'narrow block'-count", starting at 1
214 * (needed for LRW-32-AES and possible other narrow block modes)
215 *
216 * null: the initial vector is always zero. Provides compatibility with
217 * obsolete loop_fish2 devices. Do not use for new devices.
218 *
219 * lmk: Compatible implementation of the block chaining mode used
220 * by the Loop-AES block device encryption system
221 * designed by Jari Ruusu. See http://loop-aes.sourceforge.net/
222 * It operates on full 512 byte sectors and uses CBC
223 * with an IV derived from the sector number, the data and
224 * optionally extra IV seed.
225 * This means that after decryption the first block
226 * of sector must be tweaked according to decrypted data.
227 * Loop-AES can use three encryption schemes:
228 * version 1: is plain aes-cbc mode
229 * version 2: uses 64 multikey scheme with lmk IV generator
230 * version 3: the same as version 2 with additional IV seed
231 * (it uses 65 keys, last key is used as IV seed)
232 *
233 * plumb: unimplemented, see:
234 * http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454
235 */
236
237static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv,
238                  struct dm_crypt_request *dmreq)
239{
240    memset(iv, 0, cc->iv_size);
241    *(__le32 *)iv = cpu_to_le32(dmreq->iv_sector & 0xffffffff);
242
243    return 0;
244}
245
246static int crypt_iv_plain64_gen(struct crypt_config *cc, u8 *iv,
247                struct dm_crypt_request *dmreq)
248{
249    memset(iv, 0, cc->iv_size);
250    *(__le64 *)iv = cpu_to_le64(dmreq->iv_sector);
251
252    return 0;
253}
254
255/* Initialise ESSIV - compute salt but no local memory allocations */
256static int crypt_iv_essiv_init(struct crypt_config *cc)
257{
258    struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
259    struct hash_desc desc;
260    struct scatterlist sg;
261    struct crypto_cipher *essiv_tfm;
262    int err;
263
264    sg_init_one(&sg, cc->key, cc->key_size);
265    desc.tfm = essiv->hash_tfm;
266    desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
267
268    err = crypto_hash_digest(&desc, &sg, cc->key_size, essiv->salt);
269    if (err)
270        return err;
271
272    essiv_tfm = cc->iv_private;
273
274    err = crypto_cipher_setkey(essiv_tfm, essiv->salt,
275                crypto_hash_digestsize(essiv->hash_tfm));
276    if (err)
277        return err;
278
279    return 0;
280}
281
282/* Wipe salt and reset key derived from volume key */
283static int crypt_iv_essiv_wipe(struct crypt_config *cc)
284{
285    struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
286    unsigned salt_size = crypto_hash_digestsize(essiv->hash_tfm);
287    struct crypto_cipher *essiv_tfm;
288    int r, err = 0;
289
290    memset(essiv->salt, 0, salt_size);
291
292    essiv_tfm = cc->iv_private;
293    r = crypto_cipher_setkey(essiv_tfm, essiv->salt, salt_size);
294    if (r)
295        err = r;
296
297    return err;
298}
299
300/* Set up per cpu cipher state */
301static struct crypto_cipher *setup_essiv_cpu(struct crypt_config *cc,
302                         struct dm_target *ti,
303                         u8 *salt, unsigned saltsize)
304{
305    struct crypto_cipher *essiv_tfm;
306    int err;
307
308    /* Setup the essiv_tfm with the given salt */
309    essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC);
310    if (IS_ERR(essiv_tfm)) {
311        ti->error = "Error allocating crypto tfm for ESSIV";
312        return essiv_tfm;
313    }
314
315    if (crypto_cipher_blocksize(essiv_tfm) !=
316        crypto_ablkcipher_ivsize(any_tfm(cc))) {
317        ti->error = "Block size of ESSIV cipher does "
318                "not match IV size of block cipher";
319        crypto_free_cipher(essiv_tfm);
320        return ERR_PTR(-EINVAL);
321    }
322
323    err = crypto_cipher_setkey(essiv_tfm, salt, saltsize);
324    if (err) {
325        ti->error = "Failed to set key for ESSIV cipher";
326        crypto_free_cipher(essiv_tfm);
327        return ERR_PTR(err);
328    }
329
330    return essiv_tfm;
331}
332
333static void crypt_iv_essiv_dtr(struct crypt_config *cc)
334{
335    struct crypto_cipher *essiv_tfm;
336    struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
337
338    crypto_free_hash(essiv->hash_tfm);
339    essiv->hash_tfm = NULL;
340
341    kzfree(essiv->salt);
342    essiv->salt = NULL;
343
344    essiv_tfm = cc->iv_private;
345
346    if (essiv_tfm)
347        crypto_free_cipher(essiv_tfm);
348
349    cc->iv_private = NULL;
350}
351
352static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,
353                  const char *opts)
354{
355    struct crypto_cipher *essiv_tfm = NULL;
356    struct crypto_hash *hash_tfm = NULL;
357    u8 *salt = NULL;
358    int err;
359
360    if (!opts) {
361        ti->error = "Digest algorithm missing for ESSIV mode";
362        return -EINVAL;
363    }
364
365    /* Allocate hash algorithm */
366    hash_tfm = crypto_alloc_hash(opts, 0, CRYPTO_ALG_ASYNC);
367    if (IS_ERR(hash_tfm)) {
368        ti->error = "Error initializing ESSIV hash";
369        err = PTR_ERR(hash_tfm);
370        goto bad;
371    }
372
373    salt = kzalloc(crypto_hash_digestsize(hash_tfm), GFP_KERNEL);
374    if (!salt) {
375        ti->error = "Error kmallocing salt storage in ESSIV";
376        err = -ENOMEM;
377        goto bad;
378    }
379
380    cc->iv_gen_private.essiv.salt = salt;
381    cc->iv_gen_private.essiv.hash_tfm = hash_tfm;
382
383    essiv_tfm = setup_essiv_cpu(cc, ti, salt,
384                crypto_hash_digestsize(hash_tfm));
385    if (IS_ERR(essiv_tfm)) {
386        crypt_iv_essiv_dtr(cc);
387        return PTR_ERR(essiv_tfm);
388    }
389    cc->iv_private = essiv_tfm;
390
391    return 0;
392
393bad:
394    if (hash_tfm && !IS_ERR(hash_tfm))
395        crypto_free_hash(hash_tfm);
396    kfree(salt);
397    return err;
398}
399
400static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv,
401                  struct dm_crypt_request *dmreq)
402{
403    struct crypto_cipher *essiv_tfm = cc->iv_private;
404
405    memset(iv, 0, cc->iv_size);
406    *(__le64 *)iv = cpu_to_le64(dmreq->iv_sector);
407    crypto_cipher_encrypt_one(essiv_tfm, iv, iv);
408
409    return 0;
410}
411
412static int crypt_iv_benbi_ctr(struct crypt_config *cc, struct dm_target *ti,
413                  const char *opts)
414{
415    unsigned bs = crypto_ablkcipher_blocksize(any_tfm(cc));
416    int log = ilog2(bs);
417
418    /* we need to calculate how far we must shift the sector count
419     * to get the cipher block count, we use this shift in _gen */
420
421    if (1 << log != bs) {
422        ti->error = "cypher blocksize is not a power of 2";
423        return -EINVAL;
424    }
425
426    if (log > 9) {
427        ti->error = "cypher blocksize is > 512";
428        return -EINVAL;
429    }
430
431    cc->iv_gen_private.benbi.shift = 9 - log;
432
433    return 0;
434}
435
436static void crypt_iv_benbi_dtr(struct crypt_config *cc)
437{
438}
439
440static int crypt_iv_benbi_gen(struct crypt_config *cc, u8 *iv,
441                  struct dm_crypt_request *dmreq)
442{
443    __be64 val;
444
445    memset(iv, 0, cc->iv_size - sizeof(u64)); /* rest is cleared below */
446
447    val = cpu_to_be64(((u64)dmreq->iv_sector << cc->iv_gen_private.benbi.shift) + 1);
448    put_unaligned(val, (__be64 *)(iv + cc->iv_size - sizeof(u64)));
449
450    return 0;
451}
452
453static int crypt_iv_null_gen(struct crypt_config *cc, u8 *iv,
454                 struct dm_crypt_request *dmreq)
455{
456    memset(iv, 0, cc->iv_size);
457
458    return 0;
459}
460
461static void crypt_iv_lmk_dtr(struct crypt_config *cc)
462{
463    struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
464
465    if (lmk->hash_tfm && !IS_ERR(lmk->hash_tfm))
466        crypto_free_shash(lmk->hash_tfm);
467    lmk->hash_tfm = NULL;
468
469    kzfree(lmk->seed);
470    lmk->seed = NULL;
471}
472
473static int crypt_iv_lmk_ctr(struct crypt_config *cc, struct dm_target *ti,
474                const char *opts)
475{
476    struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
477
478    lmk->hash_tfm = crypto_alloc_shash("md5", 0, 0);
479    if (IS_ERR(lmk->hash_tfm)) {
480        ti->error = "Error initializing LMK hash";
481        return PTR_ERR(lmk->hash_tfm);
482    }
483
484    /* No seed in LMK version 2 */
485    if (cc->key_parts == cc->tfms_count) {
486        lmk->seed = NULL;
487        return 0;
488    }
489
490    lmk->seed = kzalloc(LMK_SEED_SIZE, GFP_KERNEL);
491    if (!lmk->seed) {
492        crypt_iv_lmk_dtr(cc);
493        ti->error = "Error kmallocing seed storage in LMK";
494        return -ENOMEM;
495    }
496
497    return 0;
498}
499
500static int crypt_iv_lmk_init(struct crypt_config *cc)
501{
502    struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
503    int subkey_size = cc->key_size / cc->key_parts;
504
505    /* LMK seed is on the position of LMK_KEYS + 1 key */
506    if (lmk->seed)
507        memcpy(lmk->seed, cc->key + (cc->tfms_count * subkey_size),
508               crypto_shash_digestsize(lmk->hash_tfm));
509
510    return 0;
511}
512
513static int crypt_iv_lmk_wipe(struct crypt_config *cc)
514{
515    struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
516
517    if (lmk->seed)
518        memset(lmk->seed, 0, LMK_SEED_SIZE);
519
520    return 0;
521}
522
523static int crypt_iv_lmk_one(struct crypt_config *cc, u8 *iv,
524                struct dm_crypt_request *dmreq,
525                u8 *data)
526{
527    struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
528    struct {
529        struct shash_desc desc;
530        char ctx[crypto_shash_descsize(lmk->hash_tfm)];
531    } sdesc;
532    struct md5_state md5state;
533    u32 buf[4];
534    int i, r;
535
536    sdesc.desc.tfm = lmk->hash_tfm;
537    sdesc.desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
538
539    r = crypto_shash_init(&sdesc.desc);
540    if (r)
541        return r;
542
543    if (lmk->seed) {
544        r = crypto_shash_update(&sdesc.desc, lmk->seed, LMK_SEED_SIZE);
545        if (r)
546            return r;
547    }
548
549    /* Sector is always 512B, block size 16, add data of blocks 1-31 */
550    r = crypto_shash_update(&sdesc.desc, data + 16, 16 * 31);
551    if (r)
552        return r;
553
554    /* Sector is cropped to 56 bits here */
555    buf[0] = cpu_to_le32(dmreq->iv_sector & 0xFFFFFFFF);
556    buf[1] = cpu_to_le32((((u64)dmreq->iv_sector >> 32) & 0x00FFFFFF) | 0x80000000);
557    buf[2] = cpu_to_le32(4024);
558    buf[3] = 0;
559    r = crypto_shash_update(&sdesc.desc, (u8 *)buf, sizeof(buf));
560    if (r)
561        return r;
562
563    /* No MD5 padding here */
564    r = crypto_shash_export(&sdesc.desc, &md5state);
565    if (r)
566        return r;
567
568    for (i = 0; i < MD5_HASH_WORDS; i++)
569        __cpu_to_le32s(&md5state.hash[i]);
570    memcpy(iv, &md5state.hash, cc->iv_size);
571
572    return 0;
573}
574
575static int crypt_iv_lmk_gen(struct crypt_config *cc, u8 *iv,
576                struct dm_crypt_request *dmreq)
577{
578    u8 *src;
579    int r = 0;
580
581    if (bio_data_dir(dmreq->ctx->bio_in) == WRITE) {
582        src = kmap_atomic(sg_page(&dmreq->sg_in));
583        r = crypt_iv_lmk_one(cc, iv, dmreq, src + dmreq->sg_in.offset);
584        kunmap_atomic(src);
585    } else
586        memset(iv, 0, cc->iv_size);
587
588    return r;
589}
590
591static int crypt_iv_lmk_post(struct crypt_config *cc, u8 *iv,
592                 struct dm_crypt_request *dmreq)
593{
594    u8 *dst;
595    int r;
596
597    if (bio_data_dir(dmreq->ctx->bio_in) == WRITE)
598        return 0;
599
600    dst = kmap_atomic(sg_page(&dmreq->sg_out));
601    r = crypt_iv_lmk_one(cc, iv, dmreq, dst + dmreq->sg_out.offset);
602
603    /* Tweak the first block of plaintext sector */
604    if (!r)
605        crypto_xor(dst + dmreq->sg_out.offset, iv, cc->iv_size);
606
607    kunmap_atomic(dst);
608    return r;
609}
610
611static struct crypt_iv_operations crypt_iv_plain_ops = {
612    .generator = crypt_iv_plain_gen
613};
614
615static struct crypt_iv_operations crypt_iv_plain64_ops = {
616    .generator = crypt_iv_plain64_gen
617};
618
619static struct crypt_iv_operations crypt_iv_essiv_ops = {
620    .ctr = crypt_iv_essiv_ctr,
621    .dtr = crypt_iv_essiv_dtr,
622    .init = crypt_iv_essiv_init,
623    .wipe = crypt_iv_essiv_wipe,
624    .generator = crypt_iv_essiv_gen
625};
626
627static struct crypt_iv_operations crypt_iv_benbi_ops = {
628    .ctr = crypt_iv_benbi_ctr,
629    .dtr = crypt_iv_benbi_dtr,
630    .generator = crypt_iv_benbi_gen
631};
632
633static struct crypt_iv_operations crypt_iv_null_ops = {
634    .generator = crypt_iv_null_gen
635};
636
637static struct crypt_iv_operations crypt_iv_lmk_ops = {
638    .ctr = crypt_iv_lmk_ctr,
639    .dtr = crypt_iv_lmk_dtr,
640    .init = crypt_iv_lmk_init,
641    .wipe = crypt_iv_lmk_wipe,
642    .generator = crypt_iv_lmk_gen,
643    .post = crypt_iv_lmk_post
644};
645
646static void crypt_convert_init(struct crypt_config *cc,
647                   struct convert_context *ctx,
648                   struct bio *bio_out, struct bio *bio_in,
649                   sector_t sector)
650{
651    ctx->bio_in = bio_in;
652    ctx->bio_out = bio_out;
653    ctx->offset_in = 0;
654    ctx->offset_out = 0;
655    ctx->idx_in = bio_in ? bio_in->bi_idx : 0;
656    ctx->idx_out = bio_out ? bio_out->bi_idx : 0;
657    ctx->cc_sector = sector + cc->iv_offset;
658    init_completion(&ctx->restart);
659}
660
661static struct dm_crypt_request *dmreq_of_req(struct crypt_config *cc,
662                         struct ablkcipher_request *req)
663{
664    return (struct dm_crypt_request *)((char *)req + cc->dmreq_start);
665}
666
667static struct ablkcipher_request *req_of_dmreq(struct crypt_config *cc,
668                           struct dm_crypt_request *dmreq)
669{
670    return (struct ablkcipher_request *)((char *)dmreq - cc->dmreq_start);
671}
672
673static u8 *iv_of_dmreq(struct crypt_config *cc,
674               struct dm_crypt_request *dmreq)
675{
676    return (u8 *)ALIGN((unsigned long)(dmreq + 1),
677        crypto_ablkcipher_alignmask(any_tfm(cc)) + 1);
678}
679
680static int crypt_convert_block(struct crypt_config *cc,
681                   struct convert_context *ctx,
682                   struct ablkcipher_request *req)
683{
684    struct bio_vec *bv_in = bio_iovec_idx(ctx->bio_in, ctx->idx_in);
685    struct bio_vec *bv_out = bio_iovec_idx(ctx->bio_out, ctx->idx_out);
686    struct dm_crypt_request *dmreq;
687    u8 *iv;
688    int r;
689
690    dmreq = dmreq_of_req(cc, req);
691    iv = iv_of_dmreq(cc, dmreq);
692
693    dmreq->iv_sector = ctx->cc_sector;
694    dmreq->ctx = ctx;
695    sg_init_table(&dmreq->sg_in, 1);
696    sg_set_page(&dmreq->sg_in, bv_in->bv_page, 1 << SECTOR_SHIFT,
697            bv_in->bv_offset + ctx->offset_in);
698
699    sg_init_table(&dmreq->sg_out, 1);
700    sg_set_page(&dmreq->sg_out, bv_out->bv_page, 1 << SECTOR_SHIFT,
701            bv_out->bv_offset + ctx->offset_out);
702
703    ctx->offset_in += 1 << SECTOR_SHIFT;
704    if (ctx->offset_in >= bv_in->bv_len) {
705        ctx->offset_in = 0;
706        ctx->idx_in++;
707    }
708
709    ctx->offset_out += 1 << SECTOR_SHIFT;
710    if (ctx->offset_out >= bv_out->bv_len) {
711        ctx->offset_out = 0;
712        ctx->idx_out++;
713    }
714
715    if (cc->iv_gen_ops) {
716        r = cc->iv_gen_ops->generator(cc, iv, dmreq);
717        if (r < 0)
718            return r;
719    }
720
721    ablkcipher_request_set_crypt(req, &dmreq->sg_in, &dmreq->sg_out,
722                     1 << SECTOR_SHIFT, iv);
723
724    if (bio_data_dir(ctx->bio_in) == WRITE)
725        r = crypto_ablkcipher_encrypt(req);
726    else
727        r = crypto_ablkcipher_decrypt(req);
728
729    if (!r && cc->iv_gen_ops && cc->iv_gen_ops->post)
730        r = cc->iv_gen_ops->post(cc, iv, dmreq);
731
732    return r;
733}
734
735static void kcryptd_async_done(struct crypto_async_request *async_req,
736                   int error);
737
738static void crypt_alloc_req(struct crypt_config *cc,
739                struct convert_context *ctx)
740{
741    struct crypt_cpu *this_cc = this_crypt_config(cc);
742    unsigned key_index = ctx->cc_sector & (cc->tfms_count - 1);
743
744    if (!this_cc->req)
745        this_cc->req = mempool_alloc(cc->req_pool, GFP_NOIO);
746
747    ablkcipher_request_set_tfm(this_cc->req, cc->tfms[key_index]);
748    ablkcipher_request_set_callback(this_cc->req,
749        CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
750        kcryptd_async_done, dmreq_of_req(cc, this_cc->req));
751}
752
753/*
754 * Encrypt / decrypt data from one bio to another one (can be the same one)
755 */
756static int crypt_convert(struct crypt_config *cc,
757             struct convert_context *ctx)
758{
759    struct crypt_cpu *this_cc = this_crypt_config(cc);
760    int r;
761
762    atomic_set(&ctx->cc_pending, 1);
763
764    while(ctx->idx_in < ctx->bio_in->bi_vcnt &&
765          ctx->idx_out < ctx->bio_out->bi_vcnt) {
766
767        crypt_alloc_req(cc, ctx);
768
769        atomic_inc(&ctx->cc_pending);
770
771        r = crypt_convert_block(cc, ctx, this_cc->req);
772
773        switch (r) {
774        /* async */
775        case -EBUSY:
776            wait_for_completion(&ctx->restart);
777            INIT_COMPLETION(ctx->restart);
778            /* fall through*/
779        case -EINPROGRESS:
780            this_cc->req = NULL;
781            ctx->cc_sector++;
782            continue;
783
784        /* sync */
785        case 0:
786            atomic_dec(&ctx->cc_pending);
787            ctx->cc_sector++;
788            cond_resched();
789            continue;
790
791        /* error */
792        default:
793            atomic_dec(&ctx->cc_pending);
794            return r;
795        }
796    }
797
798    return 0;
799}
800
801/*
802 * Generate a new unfragmented bio with the given size
803 * This should never violate the device limitations
804 * May return a smaller bio when running out of pages, indicated by
805 * *out_of_pages set to 1.
806 */
807static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size,
808                      unsigned *out_of_pages)
809{
810    struct crypt_config *cc = io->cc;
811    struct bio *clone;
812    unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
813    gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
814    unsigned i, len;
815    struct page *page;
816
817    clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs);
818    if (!clone)
819        return NULL;
820
821    clone_init(io, clone);
822    *out_of_pages = 0;
823
824    for (i = 0; i < nr_iovecs; i++) {
825        page = mempool_alloc(cc->page_pool, gfp_mask);
826        if (!page) {
827            *out_of_pages = 1;
828            break;
829        }
830
831        /*
832         * If additional pages cannot be allocated without waiting,
833         * return a partially-allocated bio. The caller will then try
834         * to allocate more bios while submitting this partial bio.
835         */
836        gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT;
837
838        len = (size > PAGE_SIZE) ? PAGE_SIZE : size;
839
840        if (!bio_add_page(clone, page, len, 0)) {
841            mempool_free(page, cc->page_pool);
842            break;
843        }
844
845        size -= len;
846    }
847
848    if (!clone->bi_size) {
849        bio_put(clone);
850        return NULL;
851    }
852
853    return clone;
854}
855
856static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone)
857{
858    unsigned int i;
859    struct bio_vec *bv;
860
861    for (i = 0; i < clone->bi_vcnt; i++) {
862        bv = bio_iovec_idx(clone, i);
863        BUG_ON(!bv->bv_page);
864        mempool_free(bv->bv_page, cc->page_pool);
865        bv->bv_page = NULL;
866    }
867}
868
869static struct dm_crypt_io *crypt_io_alloc(struct crypt_config *cc,
870                      struct bio *bio, sector_t sector)
871{
872    struct dm_crypt_io *io;
873
874    io = mempool_alloc(cc->io_pool, GFP_NOIO);
875    io->cc = cc;
876    io->base_bio = bio;
877    io->sector = sector;
878    io->error = 0;
879    io->base_io = NULL;
880    atomic_set(&io->io_pending, 0);
881
882    return io;
883}
884
885static void crypt_inc_pending(struct dm_crypt_io *io)
886{
887    atomic_inc(&io->io_pending);
888}
889
890/*
891 * One of the bios was finished. Check for completion of
892 * the whole request and correctly clean up the buffer.
893 * If base_io is set, wait for the last fragment to complete.
894 */
895static void crypt_dec_pending(struct dm_crypt_io *io)
896{
897    struct crypt_config *cc = io->cc;
898    struct bio *base_bio = io->base_bio;
899    struct dm_crypt_io *base_io = io->base_io;
900    int error = io->error;
901
902    if (!atomic_dec_and_test(&io->io_pending))
903        return;
904
905    mempool_free(io, cc->io_pool);
906
907    if (likely(!base_io))
908        bio_endio(base_bio, error);
909    else {
910        if (error && !base_io->error)
911            base_io->error = error;
912        crypt_dec_pending(base_io);
913    }
914}
915
916/*
917 * kcryptd/kcryptd_io:
918 *
919 * Needed because it would be very unwise to do decryption in an
920 * interrupt context.
921 *
922 * kcryptd performs the actual encryption or decryption.
923 *
924 * kcryptd_io performs the IO submission.
925 *
926 * They must be separated as otherwise the final stages could be
927 * starved by new requests which can block in the first stages due
928 * to memory allocation.
929 *
930 * The work is done per CPU global for all dm-crypt instances.
931 * They should not depend on each other and do not block.
932 */
933static void crypt_endio(struct bio *clone, int error)
934{
935    struct dm_crypt_io *io = clone->bi_private;
936    struct crypt_config *cc = io->cc;
937    unsigned rw = bio_data_dir(clone);
938
939    if (unlikely(!bio_flagged(clone, BIO_UPTODATE) && !error))
940        error = -EIO;
941
942    /*
943     * free the processed pages
944     */
945    if (rw == WRITE)
946        crypt_free_buffer_pages(cc, clone);
947
948    bio_put(clone);
949
950    if (rw == READ && !error) {
951        kcryptd_queue_crypt(io);
952        return;
953    }
954
955    if (unlikely(error))
956        io->error = error;
957
958    crypt_dec_pending(io);
959}
960
961static void clone_init(struct dm_crypt_io *io, struct bio *clone)
962{
963    struct crypt_config *cc = io->cc;
964
965    clone->bi_private = io;
966    clone->bi_end_io = crypt_endio;
967    clone->bi_bdev = cc->dev->bdev;
968    clone->bi_rw = io->base_bio->bi_rw;
969}
970
971static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp)
972{
973    struct crypt_config *cc = io->cc;
974    struct bio *base_bio = io->base_bio;
975    struct bio *clone;
976
977    /*
978     * The block layer might modify the bvec array, so always
979     * copy the required bvecs because we need the original
980     * one in order to decrypt the whole bio data *afterwards*.
981     */
982    clone = bio_clone_bioset(base_bio, gfp, cc->bs);
983    if (!clone)
984        return 1;
985
986    crypt_inc_pending(io);
987
988    clone_init(io, clone);
989    clone->bi_sector = cc->start + io->sector;
990
991    generic_make_request(clone);
992    return 0;
993}
994
995static void kcryptd_io_write(struct dm_crypt_io *io)
996{
997    struct bio *clone = io->ctx.bio_out;
998    generic_make_request(clone);
999}
1000
1001static void kcryptd_io(struct work_struct *work)
1002{
1003    struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
1004
1005    if (bio_data_dir(io->base_bio) == READ) {
1006        crypt_inc_pending(io);
1007        if (kcryptd_io_read(io, GFP_NOIO))
1008            io->error = -ENOMEM;
1009        crypt_dec_pending(io);
1010    } else
1011        kcryptd_io_write(io);
1012}
1013
1014static void kcryptd_queue_io(struct dm_crypt_io *io)
1015{
1016    struct crypt_config *cc = io->cc;
1017
1018    INIT_WORK(&io->work, kcryptd_io);
1019    queue_work(cc->io_queue, &io->work);
1020}
1021
1022static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io, int async)
1023{
1024    struct bio *clone = io->ctx.bio_out;
1025    struct crypt_config *cc = io->cc;
1026
1027    if (unlikely(io->error < 0)) {
1028        crypt_free_buffer_pages(cc, clone);
1029        bio_put(clone);
1030        crypt_dec_pending(io);
1031        return;
1032    }
1033
1034    /* crypt_convert should have filled the clone bio */
1035    BUG_ON(io->ctx.idx_out < clone->bi_vcnt);
1036
1037    clone->bi_sector = cc->start + io->sector;
1038
1039    if (async)
1040        kcryptd_queue_io(io);
1041    else
1042        generic_make_request(clone);
1043}
1044
1045static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
1046{
1047    struct crypt_config *cc = io->cc;
1048    struct bio *clone;
1049    struct dm_crypt_io *new_io;
1050    int crypt_finished;
1051    unsigned out_of_pages = 0;
1052    unsigned remaining = io->base_bio->bi_size;
1053    sector_t sector = io->sector;
1054    int r;
1055
1056    /*
1057     * Prevent io from disappearing until this function completes.
1058     */
1059    crypt_inc_pending(io);
1060    crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, sector);
1061
1062    /*
1063     * The allocated buffers can be smaller than the whole bio,
1064     * so repeat the whole process until all the data can be handled.
1065     */
1066    while (remaining) {
1067        clone = crypt_alloc_buffer(io, remaining, &out_of_pages);
1068        if (unlikely(!clone)) {
1069            io->error = -ENOMEM;
1070            break;
1071        }
1072
1073        io->ctx.bio_out = clone;
1074        io->ctx.idx_out = 0;
1075
1076        remaining -= clone->bi_size;
1077        sector += bio_sectors(clone);
1078
1079        crypt_inc_pending(io);
1080
1081        r = crypt_convert(cc, &io->ctx);
1082        if (r < 0)
1083            io->error = -EIO;
1084
1085        crypt_finished = atomic_dec_and_test(&io->ctx.cc_pending);
1086
1087        /* Encryption was already finished, submit io now */
1088        if (crypt_finished) {
1089            kcryptd_crypt_write_io_submit(io, 0);
1090
1091            /*
1092             * If there was an error, do not try next fragments.
1093             * For async, error is processed in async handler.
1094             */
1095            if (unlikely(r < 0))
1096                break;
1097
1098            io->sector = sector;
1099        }
1100
1101        /*
1102         * Out of memory -> run queues
1103         * But don't wait if split was due to the io size restriction
1104         */
1105        if (unlikely(out_of_pages))
1106            congestion_wait(BLK_RW_ASYNC, HZ/100);
1107
1108        /*
1109         * With async crypto it is unsafe to share the crypto context
1110         * between fragments, so switch to a new dm_crypt_io structure.
1111         */
1112        if (unlikely(!crypt_finished && remaining)) {
1113            new_io = crypt_io_alloc(io->cc, io->base_bio,
1114                        sector);
1115            crypt_inc_pending(new_io);
1116            crypt_convert_init(cc, &new_io->ctx, NULL,
1117                       io->base_bio, sector);
1118            new_io->ctx.idx_in = io->ctx.idx_in;
1119            new_io->ctx.offset_in = io->ctx.offset_in;
1120
1121            /*
1122             * Fragments after the first use the base_io
1123             * pending count.
1124             */
1125            if (!io->base_io)
1126                new_io->base_io = io;
1127            else {
1128                new_io->base_io = io->base_io;
1129                crypt_inc_pending(io->base_io);
1130                crypt_dec_pending(io);
1131            }
1132
1133            io = new_io;
1134        }
1135    }
1136
1137    crypt_dec_pending(io);
1138}
1139
1140static void kcryptd_crypt_read_done(struct dm_crypt_io *io)
1141{
1142    crypt_dec_pending(io);
1143}
1144
1145static void kcryptd_crypt_read_convert(struct dm_crypt_io *io)
1146{
1147    struct crypt_config *cc = io->cc;
1148    int r = 0;
1149
1150    crypt_inc_pending(io);
1151
1152    crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio,
1153               io->sector);
1154
1155    r = crypt_convert(cc, &io->ctx);
1156    if (r < 0)
1157        io->error = -EIO;
1158
1159    if (atomic_dec_and_test(&io->ctx.cc_pending))
1160        kcryptd_crypt_read_done(io);
1161
1162    crypt_dec_pending(io);
1163}
1164
1165static void kcryptd_async_done(struct crypto_async_request *async_req,
1166                   int error)
1167{
1168    struct dm_crypt_request *dmreq = async_req->data;
1169    struct convert_context *ctx = dmreq->ctx;
1170    struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx);
1171    struct crypt_config *cc = io->cc;
1172
1173    if (error == -EINPROGRESS) {
1174        complete(&ctx->restart);
1175        return;
1176    }
1177
1178    if (!error && cc->iv_gen_ops && cc->iv_gen_ops->post)
1179        error = cc->iv_gen_ops->post(cc, iv_of_dmreq(cc, dmreq), dmreq);
1180
1181    if (error < 0)
1182        io->error = -EIO;
1183
1184    mempool_free(req_of_dmreq(cc, dmreq), cc->req_pool);
1185
1186    if (!atomic_dec_and_test(&ctx->cc_pending))
1187        return;
1188
1189    if (bio_data_dir(io->base_bio) == READ)
1190        kcryptd_crypt_read_done(io);
1191    else
1192        kcryptd_crypt_write_io_submit(io, 1);
1193}
1194
1195static void kcryptd_crypt(struct work_struct *work)
1196{
1197    struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
1198
1199    if (bio_data_dir(io->base_bio) == READ)
1200        kcryptd_crypt_read_convert(io);
1201    else
1202        kcryptd_crypt_write_convert(io);
1203}
1204
1205static void kcryptd_queue_crypt(struct dm_crypt_io *io)
1206{
1207    struct crypt_config *cc = io->cc;
1208
1209    INIT_WORK(&io->work, kcryptd_crypt);
1210    queue_work(cc->crypt_queue, &io->work);
1211}
1212
1213/*
1214 * Decode key from its hex representation
1215 */
1216static int crypt_decode_key(u8 *key, char *hex, unsigned int size)
1217{
1218    char buffer[3];
1219    unsigned int i;
1220
1221    buffer[2] = '\0';
1222
1223    for (i = 0; i < size; i++) {
1224        buffer[0] = *hex++;
1225        buffer[1] = *hex++;
1226
1227        if (kstrtou8(buffer, 16, &key[i]))
1228            return -EINVAL;
1229    }
1230
1231    if (*hex != '\0')
1232        return -EINVAL;
1233
1234    return 0;
1235}
1236
1237static void crypt_free_tfms(struct crypt_config *cc)
1238{
1239    unsigned i;
1240
1241    if (!cc->tfms)
1242        return;
1243
1244    for (i = 0; i < cc->tfms_count; i++)
1245        if (cc->tfms[i] && !IS_ERR(cc->tfms[i])) {
1246            crypto_free_ablkcipher(cc->tfms[i]);
1247            cc->tfms[i] = NULL;
1248        }
1249
1250    kfree(cc->tfms);
1251    cc->tfms = NULL;
1252}
1253
1254static int crypt_alloc_tfms(struct crypt_config *cc, char *ciphermode)
1255{
1256    unsigned i;
1257    int err;
1258
1259    cc->tfms = kmalloc(cc->tfms_count * sizeof(struct crypto_ablkcipher *),
1260               GFP_KERNEL);
1261    if (!cc->tfms)
1262        return -ENOMEM;
1263
1264    for (i = 0; i < cc->tfms_count; i++) {
1265        cc->tfms[i] = crypto_alloc_ablkcipher(ciphermode, 0, 0);
1266        if (IS_ERR(cc->tfms[i])) {
1267            err = PTR_ERR(cc->tfms[i]);
1268            crypt_free_tfms(cc);
1269            return err;
1270        }
1271    }
1272
1273    return 0;
1274}
1275
1276static int crypt_setkey_allcpus(struct crypt_config *cc)
1277{
1278    unsigned subkey_size = cc->key_size >> ilog2(cc->tfms_count);
1279    int err = 0, i, r;
1280
1281    for (i = 0; i < cc->tfms_count; i++) {
1282        r = crypto_ablkcipher_setkey(cc->tfms[i],
1283                         cc->key + (i * subkey_size),
1284                         subkey_size);
1285        if (r)
1286            err = r;
1287    }
1288
1289    return err;
1290}
1291
1292static int crypt_set_key(struct crypt_config *cc, char *key)
1293{
1294    int r = -EINVAL;
1295    int key_string_len = strlen(key);
1296
1297    /* The key size may not be changed. */
1298    if (cc->key_size != (key_string_len >> 1))
1299        goto out;
1300
1301    /* Hyphen (which gives a key_size of zero) means there is no key. */
1302    if (!cc->key_size && strcmp(key, "-"))
1303        goto out;
1304
1305    if (cc->key_size && crypt_decode_key(cc->key, key, cc->key_size) < 0)
1306        goto out;
1307
1308    set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
1309
1310    r = crypt_setkey_allcpus(cc);
1311
1312out:
1313    /* Hex key string not needed after here, so wipe it. */
1314    memset(key, '0', key_string_len);
1315
1316    return r;
1317}
1318
1319static int crypt_wipe_key(struct crypt_config *cc)
1320{
1321    clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
1322    memset(&cc->key, 0, cc->key_size * sizeof(u8));
1323
1324    return crypt_setkey_allcpus(cc);
1325}
1326
1327static void crypt_dtr(struct dm_target *ti)
1328{
1329    struct crypt_config *cc = ti->private;
1330    struct crypt_cpu *cpu_cc;
1331    int cpu;
1332
1333    ti->private = NULL;
1334
1335    if (!cc)
1336        return;
1337
1338    if (cc->io_queue)
1339        destroy_workqueue(cc->io_queue);
1340    if (cc->crypt_queue)
1341        destroy_workqueue(cc->crypt_queue);
1342
1343    if (cc->cpu)
1344        for_each_possible_cpu(cpu) {
1345            cpu_cc = per_cpu_ptr(cc->cpu, cpu);
1346            if (cpu_cc->req)
1347                mempool_free(cpu_cc->req, cc->req_pool);
1348        }
1349
1350    crypt_free_tfms(cc);
1351
1352    if (cc->bs)
1353        bioset_free(cc->bs);
1354
1355    if (cc->page_pool)
1356        mempool_destroy(cc->page_pool);
1357    if (cc->req_pool)
1358        mempool_destroy(cc->req_pool);
1359    if (cc->io_pool)
1360        mempool_destroy(cc->io_pool);
1361
1362    if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
1363        cc->iv_gen_ops->dtr(cc);
1364
1365    if (cc->dev)
1366        dm_put_device(ti, cc->dev);
1367
1368    if (cc->cpu)
1369        free_percpu(cc->cpu);
1370
1371    kzfree(cc->cipher);
1372    kzfree(cc->cipher_string);
1373
1374    /* Must zero key material before freeing */
1375    kzfree(cc);
1376}
1377
1378static int crypt_ctr_cipher(struct dm_target *ti,
1379                char *cipher_in, char *key)
1380{
1381    struct crypt_config *cc = ti->private;
1382    char *tmp, *cipher, *chainmode, *ivmode, *ivopts, *keycount;
1383    char *cipher_api = NULL;
1384    int ret = -EINVAL;
1385    char dummy;
1386
1387    /* Convert to crypto api definition? */
1388    if (strchr(cipher_in, '(')) {
1389        ti->error = "Bad cipher specification";
1390        return -EINVAL;
1391    }
1392
1393    cc->cipher_string = kstrdup(cipher_in, GFP_KERNEL);
1394    if (!cc->cipher_string)
1395        goto bad_mem;
1396
1397    /*
1398     * Legacy dm-crypt cipher specification
1399     * cipher[:keycount]-mode-iv:ivopts
1400     */
1401    tmp = cipher_in;
1402    keycount = strsep(&tmp, "-");
1403    cipher = strsep(&keycount, ":");
1404
1405    if (!keycount)
1406        cc->tfms_count = 1;
1407    else if (sscanf(keycount, "%u%c", &cc->tfms_count, &dummy) != 1 ||
1408         !is_power_of_2(cc->tfms_count)) {
1409        ti->error = "Bad cipher key count specification";
1410        return -EINVAL;
1411    }
1412    cc->key_parts = cc->tfms_count;
1413
1414    cc->cipher = kstrdup(cipher, GFP_KERNEL);
1415    if (!cc->cipher)
1416        goto bad_mem;
1417
1418    chainmode = strsep(&tmp, "-");
1419    ivopts = strsep(&tmp, "-");
1420    ivmode = strsep(&ivopts, ":");
1421
1422    if (tmp)
1423        DMWARN("Ignoring unexpected additional cipher options");
1424
1425    cc->cpu = __alloc_percpu(sizeof(*(cc->cpu)),
1426                 __alignof__(struct crypt_cpu));
1427    if (!cc->cpu) {
1428        ti->error = "Cannot allocate per cpu state";
1429        goto bad_mem;
1430    }
1431
1432    /*
1433     * For compatibility with the original dm-crypt mapping format, if
1434     * only the cipher name is supplied, use cbc-plain.
1435     */
1436    if (!chainmode || (!strcmp(chainmode, "plain") && !ivmode)) {
1437        chainmode = "cbc";
1438        ivmode = "plain";
1439    }
1440
1441    if (strcmp(chainmode, "ecb") && !ivmode) {
1442        ti->error = "IV mechanism required";
1443        return -EINVAL;
1444    }
1445
1446    cipher_api = kmalloc(CRYPTO_MAX_ALG_NAME, GFP_KERNEL);
1447    if (!cipher_api)
1448        goto bad_mem;
1449
1450    ret = snprintf(cipher_api, CRYPTO_MAX_ALG_NAME,
1451               "%s(%s)", chainmode, cipher);
1452    if (ret < 0) {
1453        kfree(cipher_api);
1454        goto bad_mem;
1455    }
1456
1457    /* Allocate cipher */
1458    ret = crypt_alloc_tfms(cc, cipher_api);
1459    if (ret < 0) {
1460        ti->error = "Error allocating crypto tfm";
1461        goto bad;
1462    }
1463
1464    /* Initialize and set key */
1465    ret = crypt_set_key(cc, key);
1466    if (ret < 0) {
1467        ti->error = "Error decoding and setting key";
1468        goto bad;
1469    }
1470
1471    /* Initialize IV */
1472    cc->iv_size = crypto_ablkcipher_ivsize(any_tfm(cc));
1473    if (cc->iv_size)
1474        /* at least a 64 bit sector number should fit in our buffer */
1475        cc->iv_size = max(cc->iv_size,
1476                  (unsigned int)(sizeof(u64) / sizeof(u8)));
1477    else if (ivmode) {
1478        DMWARN("Selected cipher does not support IVs");
1479        ivmode = NULL;
1480    }
1481
1482    /* Choose ivmode, see comments at iv code. */
1483    if (ivmode == NULL)
1484        cc->iv_gen_ops = NULL;
1485    else if (strcmp(ivmode, "plain") == 0)
1486        cc->iv_gen_ops = &crypt_iv_plain_ops;
1487    else if (strcmp(ivmode, "plain64") == 0)
1488        cc->iv_gen_ops = &crypt_iv_plain64_ops;
1489    else if (strcmp(ivmode, "essiv") == 0)
1490        cc->iv_gen_ops = &crypt_iv_essiv_ops;
1491    else if (strcmp(ivmode, "benbi") == 0)
1492        cc->iv_gen_ops = &crypt_iv_benbi_ops;
1493    else if (strcmp(ivmode, "null") == 0)
1494        cc->iv_gen_ops = &crypt_iv_null_ops;
1495    else if (strcmp(ivmode, "lmk") == 0) {
1496        cc->iv_gen_ops = &crypt_iv_lmk_ops;
1497        /* Version 2 and 3 is recognised according
1498         * to length of provided multi-key string.
1499         * If present (version 3), last key is used as IV seed.
1500         */
1501        if (cc->key_size % cc->key_parts)
1502            cc->key_parts++;
1503    } else {
1504        ret = -EINVAL;
1505        ti->error = "Invalid IV mode";
1506        goto bad;
1507    }
1508
1509    /* Allocate IV */
1510    if (cc->iv_gen_ops && cc->iv_gen_ops->ctr) {
1511        ret = cc->iv_gen_ops->ctr(cc, ti, ivopts);
1512        if (ret < 0) {
1513            ti->error = "Error creating IV";
1514            goto bad;
1515        }
1516    }
1517
1518    /* Initialize IV (set keys for ESSIV etc) */
1519    if (cc->iv_gen_ops && cc->iv_gen_ops->init) {
1520        ret = cc->iv_gen_ops->init(cc);
1521        if (ret < 0) {
1522            ti->error = "Error initialising IV";
1523            goto bad;
1524        }
1525    }
1526
1527    ret = 0;
1528bad:
1529    kfree(cipher_api);
1530    return ret;
1531
1532bad_mem:
1533    ti->error = "Cannot allocate cipher strings";
1534    return -ENOMEM;
1535}
1536
1537/*
1538 * Construct an encryption mapping:
1539 * <cipher> <key> <iv_offset> <dev_path> <start>
1540 */
1541static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
1542{
1543    struct crypt_config *cc;
1544    unsigned int key_size, opt_params;
1545    unsigned long long tmpll;
1546    int ret;
1547    struct dm_arg_set as;
1548    const char *opt_string;
1549    char dummy;
1550
1551    static struct dm_arg _args[] = {
1552        {0, 1, "Invalid number of feature args"},
1553    };
1554
1555    if (argc < 5) {
1556        ti->error = "Not enough arguments";
1557        return -EINVAL;
1558    }
1559
1560    key_size = strlen(argv[1]) >> 1;
1561
1562    cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
1563    if (!cc) {
1564        ti->error = "Cannot allocate encryption context";
1565        return -ENOMEM;
1566    }
1567    cc->key_size = key_size;
1568
1569    ti->private = cc;
1570    ret = crypt_ctr_cipher(ti, argv[0], argv[1]);
1571    if (ret < 0)
1572        goto bad;
1573
1574    ret = -ENOMEM;
1575    cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool);
1576    if (!cc->io_pool) {
1577        ti->error = "Cannot allocate crypt io mempool";
1578        goto bad;
1579    }
1580
1581    cc->dmreq_start = sizeof(struct ablkcipher_request);
1582    cc->dmreq_start += crypto_ablkcipher_reqsize(any_tfm(cc));
1583    cc->dmreq_start = ALIGN(cc->dmreq_start, crypto_tfm_ctx_alignment());
1584    cc->dmreq_start += crypto_ablkcipher_alignmask(any_tfm(cc)) &
1585               ~(crypto_tfm_ctx_alignment() - 1);
1586
1587    cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start +
1588            sizeof(struct dm_crypt_request) + cc->iv_size);
1589    if (!cc->req_pool) {
1590        ti->error = "Cannot allocate crypt request mempool";
1591        goto bad;
1592    }
1593
1594    cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0);
1595    if (!cc->page_pool) {
1596        ti->error = "Cannot allocate page mempool";
1597        goto bad;
1598    }
1599
1600    cc->bs = bioset_create(MIN_IOS, 0);
1601    if (!cc->bs) {
1602        ti->error = "Cannot allocate crypt bioset";
1603        goto bad;
1604    }
1605
1606    ret = -EINVAL;
1607    if (sscanf(argv[2], "%llu%c", &tmpll, &dummy) != 1) {
1608        ti->error = "Invalid iv_offset sector";
1609        goto bad;
1610    }
1611    cc->iv_offset = tmpll;
1612
1613    if (dm_get_device(ti, argv[3], dm_table_get_mode(ti->table), &cc->dev)) {
1614        ti->error = "Device lookup failed";
1615        goto bad;
1616    }
1617
1618    if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1) {
1619        ti->error = "Invalid device sector";
1620        goto bad;
1621    }
1622    cc->start = tmpll;
1623
1624    argv += 5;
1625    argc -= 5;
1626
1627    /* Optional parameters */
1628    if (argc) {
1629        as.argc = argc;
1630        as.argv = argv;
1631
1632        ret = dm_read_arg_group(_args, &as, &opt_params, &ti->error);
1633        if (ret)
1634            goto bad;
1635
1636        opt_string = dm_shift_arg(&as);
1637
1638        if (opt_params == 1 && opt_string &&
1639            !strcasecmp(opt_string, "allow_discards"))
1640            ti->num_discard_bios = 1;
1641        else if (opt_params) {
1642            ret = -EINVAL;
1643            ti->error = "Invalid feature arguments";
1644            goto bad;
1645        }
1646    }
1647
1648    ret = -ENOMEM;
1649    cc->io_queue = alloc_workqueue("kcryptd_io",
1650                       WQ_NON_REENTRANT|
1651                       WQ_MEM_RECLAIM,
1652                       1);
1653    if (!cc->io_queue) {
1654        ti->error = "Couldn't create kcryptd io queue";
1655        goto bad;
1656    }
1657
1658    cc->crypt_queue = alloc_workqueue("kcryptd",
1659                      WQ_NON_REENTRANT|
1660                      WQ_CPU_INTENSIVE|
1661                      WQ_MEM_RECLAIM,
1662                      1);
1663    if (!cc->crypt_queue) {
1664        ti->error = "Couldn't create kcryptd queue";
1665        goto bad;
1666    }
1667
1668    ti->num_flush_bios = 1;
1669    ti->discard_zeroes_data_unsupported = true;
1670
1671    return 0;
1672
1673bad:
1674    crypt_dtr(ti);
1675    return ret;
1676}
1677
1678static int crypt_map(struct dm_target *ti, struct bio *bio)
1679{
1680    struct dm_crypt_io *io;
1681    struct crypt_config *cc = ti->private;
1682
1683    /*
1684     * If bio is REQ_FLUSH or REQ_DISCARD, just bypass crypt queues.
1685     * - for REQ_FLUSH device-mapper core ensures that no IO is in-flight
1686     * - for REQ_DISCARD caller must use flush if IO ordering matters
1687     */
1688    if (unlikely(bio->bi_rw & (REQ_FLUSH | REQ_DISCARD))) {
1689        bio->bi_bdev = cc->dev->bdev;
1690        if (bio_sectors(bio))
1691            bio->bi_sector = cc->start + dm_target_offset(ti, bio->bi_sector);
1692        return DM_MAPIO_REMAPPED;
1693    }
1694
1695    io = crypt_io_alloc(cc, bio, dm_target_offset(ti, bio->bi_sector));
1696
1697    if (bio_data_dir(io->base_bio) == READ) {
1698        if (kcryptd_io_read(io, GFP_NOWAIT))
1699            kcryptd_queue_io(io);
1700    } else
1701        kcryptd_queue_crypt(io);
1702
1703    return DM_MAPIO_SUBMITTED;
1704}
1705
1706static void crypt_status(struct dm_target *ti, status_type_t type,
1707             unsigned status_flags, char *result, unsigned maxlen)
1708{
1709    struct crypt_config *cc = ti->private;
1710    unsigned i, sz = 0;
1711
1712    switch (type) {
1713    case STATUSTYPE_INFO:
1714        result[0] = '\0';
1715        break;
1716
1717    case STATUSTYPE_TABLE:
1718        DMEMIT("%s ", cc->cipher_string);
1719
1720        if (cc->key_size > 0)
1721            for (i = 0; i < cc->key_size; i++)
1722                DMEMIT("%02x", cc->key[i]);
1723        else
1724            DMEMIT("-");
1725
1726        DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset,
1727                cc->dev->name, (unsigned long long)cc->start);
1728
1729        if (ti->num_discard_bios)
1730            DMEMIT(" 1 allow_discards");
1731
1732        break;
1733    }
1734}
1735
1736static void crypt_postsuspend(struct dm_target *ti)
1737{
1738    struct crypt_config *cc = ti->private;
1739
1740    set_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1741}
1742
1743static int crypt_preresume(struct dm_target *ti)
1744{
1745    struct crypt_config *cc = ti->private;
1746
1747    if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) {
1748        DMERR("aborting resume - crypt key is not set.");
1749        return -EAGAIN;
1750    }
1751
1752    return 0;
1753}
1754
1755static void crypt_resume(struct dm_target *ti)
1756{
1757    struct crypt_config *cc = ti->private;
1758
1759    clear_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1760}
1761
1762/* Message interface
1763 * key set <key>
1764 * key wipe
1765 */
1766static int crypt_message(struct dm_target *ti, unsigned argc, char **argv)
1767{
1768    struct crypt_config *cc = ti->private;
1769    int ret = -EINVAL;
1770
1771    if (argc < 2)
1772        goto error;
1773
1774    if (!strcasecmp(argv[0], "key")) {
1775        if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) {
1776            DMWARN("not suspended during key manipulation.");
1777            return -EINVAL;
1778        }
1779        if (argc == 3 && !strcasecmp(argv[1], "set")) {
1780            ret = crypt_set_key(cc, argv[2]);
1781            if (ret)
1782                return ret;
1783            if (cc->iv_gen_ops && cc->iv_gen_ops->init)
1784                ret = cc->iv_gen_ops->init(cc);
1785            return ret;
1786        }
1787        if (argc == 2 && !strcasecmp(argv[1], "wipe")) {
1788            if (cc->iv_gen_ops && cc->iv_gen_ops->wipe) {
1789                ret = cc->iv_gen_ops->wipe(cc);
1790                if (ret)
1791                    return ret;
1792            }
1793            return crypt_wipe_key(cc);
1794        }
1795    }
1796
1797error:
1798    DMWARN("unrecognised message received.");
1799    return -EINVAL;
1800}
1801
1802static int crypt_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
1803               struct bio_vec *biovec, int max_size)
1804{
1805    struct crypt_config *cc = ti->private;
1806    struct request_queue *q = bdev_get_queue(cc->dev->bdev);
1807
1808    if (!q->merge_bvec_fn)
1809        return max_size;
1810
1811    bvm->bi_bdev = cc->dev->bdev;
1812    bvm->bi_sector = cc->start + dm_target_offset(ti, bvm->bi_sector);
1813
1814    return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
1815}
1816
1817static int crypt_iterate_devices(struct dm_target *ti,
1818                 iterate_devices_callout_fn fn, void *data)
1819{
1820    struct crypt_config *cc = ti->private;
1821
1822    return fn(ti, cc->dev, cc->start, ti->len, data);
1823}
1824
1825static struct target_type crypt_target = {
1826    .name = "crypt",
1827    .version = {1, 12, 1},
1828    .module = THIS_MODULE,
1829    .ctr = crypt_ctr,
1830    .dtr = crypt_dtr,
1831    .map = crypt_map,
1832    .status = crypt_status,
1833    .postsuspend = crypt_postsuspend,
1834    .preresume = crypt_preresume,
1835    .resume = crypt_resume,
1836    .message = crypt_message,
1837    .merge = crypt_merge,
1838    .iterate_devices = crypt_iterate_devices,
1839};
1840
1841static int __init dm_crypt_init(void)
1842{
1843    int r;
1844
1845    _crypt_io_pool = KMEM_CACHE(dm_crypt_io, 0);
1846    if (!_crypt_io_pool)
1847        return -ENOMEM;
1848
1849    r = dm_register_target(&crypt_target);
1850    if (r < 0) {
1851        DMERR("register failed %d", r);
1852        kmem_cache_destroy(_crypt_io_pool);
1853    }
1854
1855    return r;
1856}
1857
1858static void __exit dm_crypt_exit(void)
1859{
1860    dm_unregister_target(&crypt_target);
1861    kmem_cache_destroy(_crypt_io_pool);
1862}
1863
1864module_init(dm_crypt_init);
1865module_exit(dm_crypt_exit);
1866
1867MODULE_AUTHOR("Christophe Saout <christophe@saout.de>");
1868MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption");
1869MODULE_LICENSE("GPL");
1870

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