2 * Copyright (C) 2003 Jana Saout <jana@saout.de>
3 * Copyright (C) 2004 Clemens Fruhwirth <clemens@endorphin.org>
4 * Copyright (C) 2006-2015 Red Hat, Inc. All rights reserved.
5 * Copyright (C) 2013 Milan Broz <gmazyland@gmail.com>
7 * This file is released under the GPL.
10 #include <linux/completion.h>
11 #include <linux/err.h>
12 #include <linux/module.h>
13 #include <linux/init.h>
14 #include <linux/kernel.h>
15 #include <linux/bio.h>
16 #include <linux/blkdev.h>
17 #include <linux/mempool.h>
18 #include <linux/slab.h>
19 #include <linux/crypto.h>
20 #include <linux/workqueue.h>
21 #include <linux/kthread.h>
22 #include <linux/backing-dev.h>
23 #include <linux/atomic.h>
24 #include <linux/scatterlist.h>
25 #include <linux/rbtree.h>
27 #include <asm/unaligned.h>
28 #include <crypto/hash.h>
29 #include <crypto/md5.h>
30 #include <crypto/algapi.h>
31 #include <crypto/skcipher.h>
33 #include <linux/device-mapper.h>
35 #define DM_MSG_PREFIX "crypt"
38 * context holding the current state of a multi-part conversion
40 struct convert_context {
41 struct completion restart;
44 struct bvec_iter iter_in;
45 struct bvec_iter iter_out;
48 struct skcipher_request *req;
52 * per bio private data
55 struct crypt_config *cc;
57 struct work_struct work;
59 struct convert_context ctx;
65 struct rb_node rb_node;
66 } CRYPTO_MINALIGN_ATTR;
68 struct dm_crypt_request {
69 struct convert_context *ctx;
70 struct scatterlist sg_in;
71 struct scatterlist sg_out;
77 struct crypt_iv_operations {
78 int (*ctr)(struct crypt_config *cc, struct dm_target *ti,
80 void (*dtr)(struct crypt_config *cc);
81 int (*init)(struct crypt_config *cc);
82 int (*wipe)(struct crypt_config *cc);
83 int (*generator)(struct crypt_config *cc, u8 *iv,
84 struct dm_crypt_request *dmreq);
85 int (*post)(struct crypt_config *cc, u8 *iv,
86 struct dm_crypt_request *dmreq);
89 struct iv_essiv_private {
90 struct crypto_ahash *hash_tfm;
94 struct iv_benbi_private {
98 #define LMK_SEED_SIZE 64 /* hash + 0 */
99 struct iv_lmk_private {
100 struct crypto_shash *hash_tfm;
104 #define TCW_WHITENING_SIZE 16
105 struct iv_tcw_private {
106 struct crypto_shash *crc32_tfm;
112 * Crypt: maps a linear range of a block device
113 * and encrypts / decrypts at the same time.
115 enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID,
116 DM_CRYPT_SAME_CPU, DM_CRYPT_NO_OFFLOAD };
119 * The fields in here must be read only after initialization.
121 struct crypt_config {
126 * pool for per bio private data, crypto requests and
127 * encryption requeusts/buffer pages
130 mempool_t *page_pool;
132 struct mutex bio_alloc_lock;
134 struct workqueue_struct *io_queue;
135 struct workqueue_struct *crypt_queue;
137 struct task_struct *write_thread;
138 wait_queue_head_t write_thread_wait;
139 struct rb_root write_tree;
144 struct crypt_iv_operations *iv_gen_ops;
146 struct iv_essiv_private essiv;
147 struct iv_benbi_private benbi;
148 struct iv_lmk_private lmk;
149 struct iv_tcw_private tcw;
152 unsigned int iv_size;
154 /* ESSIV: struct crypto_cipher *essiv_tfm */
156 struct crypto_skcipher **tfms;
160 * Layout of each crypto request:
162 * struct skcipher_request
165 * struct dm_crypt_request
169 * The padding is added so that dm_crypt_request and the IV are
172 unsigned int dmreq_start;
174 unsigned int per_bio_data_size;
177 unsigned int key_size;
178 unsigned int key_parts; /* independent parts in key buffer */
179 unsigned int key_extra_size; /* additional keys length */
185 static void clone_init(struct dm_crypt_io *, struct bio *);
186 static void kcryptd_queue_crypt(struct dm_crypt_io *io);
187 static u8 *iv_of_dmreq(struct crypt_config *cc, struct dm_crypt_request *dmreq);
190 * Use this to access cipher attributes that are the same for each CPU.
192 static struct crypto_skcipher *any_tfm(struct crypt_config *cc)
198 * Different IV generation algorithms:
200 * plain: the initial vector is the 32-bit little-endian version of the sector
201 * number, padded with zeros if necessary.
203 * plain64: the initial vector is the 64-bit little-endian version of the sector
204 * number, padded with zeros if necessary.
206 * essiv: "encrypted sector|salt initial vector", the sector number is
207 * encrypted with the bulk cipher using a salt as key. The salt
208 * should be derived from the bulk cipher's key via hashing.
210 * benbi: the 64-bit "big-endian 'narrow block'-count", starting at 1
211 * (needed for LRW-32-AES and possible other narrow block modes)
213 * null: the initial vector is always zero. Provides compatibility with
214 * obsolete loop_fish2 devices. Do not use for new devices.
216 * lmk: Compatible implementation of the block chaining mode used
217 * by the Loop-AES block device encryption system
218 * designed by Jari Ruusu. See http://loop-aes.sourceforge.net/
219 * It operates on full 512 byte sectors and uses CBC
220 * with an IV derived from the sector number, the data and
221 * optionally extra IV seed.
222 * This means that after decryption the first block
223 * of sector must be tweaked according to decrypted data.
224 * Loop-AES can use three encryption schemes:
225 * version 1: is plain aes-cbc mode
226 * version 2: uses 64 multikey scheme with lmk IV generator
227 * version 3: the same as version 2 with additional IV seed
228 * (it uses 65 keys, last key is used as IV seed)
230 * tcw: Compatible implementation of the block chaining mode used
231 * by the TrueCrypt device encryption system (prior to version 4.1).
232 * For more info see: https://gitlab.com/cryptsetup/cryptsetup/wikis/TrueCryptOnDiskFormat
233 * It operates on full 512 byte sectors and uses CBC
234 * with an IV derived from initial key and the sector number.
235 * In addition, whitening value is applied on every sector, whitening
236 * is calculated from initial key, sector number and mixed using CRC32.
237 * Note that this encryption scheme is vulnerable to watermarking attacks
238 * and should be used for old compatible containers access only.
240 * plumb: unimplemented, see:
241 * http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454
244 static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv,
245 struct dm_crypt_request *dmreq)
247 memset(iv, 0, cc->iv_size);
248 *(__le32 *)iv = cpu_to_le32(dmreq->iv_sector & 0xffffffff);
253 static int crypt_iv_plain64_gen(struct crypt_config *cc, u8 *iv,
254 struct dm_crypt_request *dmreq)
256 memset(iv, 0, cc->iv_size);
257 *(__le64 *)iv = cpu_to_le64(dmreq->iv_sector);
262 /* Initialise ESSIV - compute salt but no local memory allocations */
263 static int crypt_iv_essiv_init(struct crypt_config *cc)
265 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
266 AHASH_REQUEST_ON_STACK(req, essiv->hash_tfm);
267 struct scatterlist sg;
268 struct crypto_cipher *essiv_tfm;
271 sg_init_one(&sg, cc->key, cc->key_size);
272 ahash_request_set_tfm(req, essiv->hash_tfm);
273 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
274 ahash_request_set_crypt(req, &sg, essiv->salt, cc->key_size);
276 err = crypto_ahash_digest(req);
277 ahash_request_zero(req);
281 essiv_tfm = cc->iv_private;
283 err = crypto_cipher_setkey(essiv_tfm, essiv->salt,
284 crypto_ahash_digestsize(essiv->hash_tfm));
291 /* Wipe salt and reset key derived from volume key */
292 static int crypt_iv_essiv_wipe(struct crypt_config *cc)
294 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
295 unsigned salt_size = crypto_ahash_digestsize(essiv->hash_tfm);
296 struct crypto_cipher *essiv_tfm;
299 memset(essiv->salt, 0, salt_size);
301 essiv_tfm = cc->iv_private;
302 r = crypto_cipher_setkey(essiv_tfm, essiv->salt, salt_size);
309 /* Set up per cpu cipher state */
310 static struct crypto_cipher *setup_essiv_cpu(struct crypt_config *cc,
311 struct dm_target *ti,
312 u8 *salt, unsigned saltsize)
314 struct crypto_cipher *essiv_tfm;
317 /* Setup the essiv_tfm with the given salt */
318 essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC);
319 if (IS_ERR(essiv_tfm)) {
320 ti->error = "Error allocating crypto tfm for ESSIV";
324 if (crypto_cipher_blocksize(essiv_tfm) !=
325 crypto_skcipher_ivsize(any_tfm(cc))) {
326 ti->error = "Block size of ESSIV cipher does "
327 "not match IV size of block cipher";
328 crypto_free_cipher(essiv_tfm);
329 return ERR_PTR(-EINVAL);
332 err = crypto_cipher_setkey(essiv_tfm, salt, saltsize);
334 ti->error = "Failed to set key for ESSIV cipher";
335 crypto_free_cipher(essiv_tfm);
342 static void crypt_iv_essiv_dtr(struct crypt_config *cc)
344 struct crypto_cipher *essiv_tfm;
345 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
347 crypto_free_ahash(essiv->hash_tfm);
348 essiv->hash_tfm = NULL;
353 essiv_tfm = cc->iv_private;
356 crypto_free_cipher(essiv_tfm);
358 cc->iv_private = NULL;
361 static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,
364 struct crypto_cipher *essiv_tfm = NULL;
365 struct crypto_ahash *hash_tfm = NULL;
370 ti->error = "Digest algorithm missing for ESSIV mode";
374 /* Allocate hash algorithm */
375 hash_tfm = crypto_alloc_ahash(opts, 0, CRYPTO_ALG_ASYNC);
376 if (IS_ERR(hash_tfm)) {
377 ti->error = "Error initializing ESSIV hash";
378 err = PTR_ERR(hash_tfm);
382 salt = kzalloc(crypto_ahash_digestsize(hash_tfm), GFP_KERNEL);
384 ti->error = "Error kmallocing salt storage in ESSIV";
389 cc->iv_gen_private.essiv.salt = salt;
390 cc->iv_gen_private.essiv.hash_tfm = hash_tfm;
392 essiv_tfm = setup_essiv_cpu(cc, ti, salt,
393 crypto_ahash_digestsize(hash_tfm));
394 if (IS_ERR(essiv_tfm)) {
395 crypt_iv_essiv_dtr(cc);
396 return PTR_ERR(essiv_tfm);
398 cc->iv_private = essiv_tfm;
403 if (hash_tfm && !IS_ERR(hash_tfm))
404 crypto_free_ahash(hash_tfm);
409 static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv,
410 struct dm_crypt_request *dmreq)
412 struct crypto_cipher *essiv_tfm = cc->iv_private;
414 memset(iv, 0, cc->iv_size);
415 *(__le64 *)iv = cpu_to_le64(dmreq->iv_sector);
416 crypto_cipher_encrypt_one(essiv_tfm, iv, iv);
421 static int crypt_iv_benbi_ctr(struct crypt_config *cc, struct dm_target *ti,
424 unsigned bs = crypto_skcipher_blocksize(any_tfm(cc));
427 /* we need to calculate how far we must shift the sector count
428 * to get the cipher block count, we use this shift in _gen */
430 if (1 << log != bs) {
431 ti->error = "cypher blocksize is not a power of 2";
436 ti->error = "cypher blocksize is > 512";
440 cc->iv_gen_private.benbi.shift = 9 - log;
445 static void crypt_iv_benbi_dtr(struct crypt_config *cc)
449 static int crypt_iv_benbi_gen(struct crypt_config *cc, u8 *iv,
450 struct dm_crypt_request *dmreq)
454 memset(iv, 0, cc->iv_size - sizeof(u64)); /* rest is cleared below */
456 val = cpu_to_be64(((u64)dmreq->iv_sector << cc->iv_gen_private.benbi.shift) + 1);
457 put_unaligned(val, (__be64 *)(iv + cc->iv_size - sizeof(u64)));
462 static int crypt_iv_null_gen(struct crypt_config *cc, u8 *iv,
463 struct dm_crypt_request *dmreq)
465 memset(iv, 0, cc->iv_size);
470 static void crypt_iv_lmk_dtr(struct crypt_config *cc)
472 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
474 if (lmk->hash_tfm && !IS_ERR(lmk->hash_tfm))
475 crypto_free_shash(lmk->hash_tfm);
476 lmk->hash_tfm = NULL;
482 static int crypt_iv_lmk_ctr(struct crypt_config *cc, struct dm_target *ti,
485 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
487 lmk->hash_tfm = crypto_alloc_shash("md5", 0, 0);
488 if (IS_ERR(lmk->hash_tfm)) {
489 ti->error = "Error initializing LMK hash";
490 return PTR_ERR(lmk->hash_tfm);
493 /* No seed in LMK version 2 */
494 if (cc->key_parts == cc->tfms_count) {
499 lmk->seed = kzalloc(LMK_SEED_SIZE, GFP_KERNEL);
501 crypt_iv_lmk_dtr(cc);
502 ti->error = "Error kmallocing seed storage in LMK";
509 static int crypt_iv_lmk_init(struct crypt_config *cc)
511 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
512 int subkey_size = cc->key_size / cc->key_parts;
514 /* LMK seed is on the position of LMK_KEYS + 1 key */
516 memcpy(lmk->seed, cc->key + (cc->tfms_count * subkey_size),
517 crypto_shash_digestsize(lmk->hash_tfm));
522 static int crypt_iv_lmk_wipe(struct crypt_config *cc)
524 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
527 memset(lmk->seed, 0, LMK_SEED_SIZE);
532 static int crypt_iv_lmk_one(struct crypt_config *cc, u8 *iv,
533 struct dm_crypt_request *dmreq,
536 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
537 SHASH_DESC_ON_STACK(desc, lmk->hash_tfm);
538 struct md5_state md5state;
542 desc->tfm = lmk->hash_tfm;
543 desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
545 r = crypto_shash_init(desc);
550 r = crypto_shash_update(desc, lmk->seed, LMK_SEED_SIZE);
555 /* Sector is always 512B, block size 16, add data of blocks 1-31 */
556 r = crypto_shash_update(desc, data + 16, 16 * 31);
560 /* Sector is cropped to 56 bits here */
561 buf[0] = cpu_to_le32(dmreq->iv_sector & 0xFFFFFFFF);
562 buf[1] = cpu_to_le32((((u64)dmreq->iv_sector >> 32) & 0x00FFFFFF) | 0x80000000);
563 buf[2] = cpu_to_le32(4024);
565 r = crypto_shash_update(desc, (u8 *)buf, sizeof(buf));
569 /* No MD5 padding here */
570 r = crypto_shash_export(desc, &md5state);
574 for (i = 0; i < MD5_HASH_WORDS; i++)
575 __cpu_to_le32s(&md5state.hash[i]);
576 memcpy(iv, &md5state.hash, cc->iv_size);
581 static int crypt_iv_lmk_gen(struct crypt_config *cc, u8 *iv,
582 struct dm_crypt_request *dmreq)
587 if (bio_data_dir(dmreq->ctx->bio_in) == WRITE) {
588 src = kmap_atomic(sg_page(&dmreq->sg_in));
589 r = crypt_iv_lmk_one(cc, iv, dmreq, src + dmreq->sg_in.offset);
592 memset(iv, 0, cc->iv_size);
597 static int crypt_iv_lmk_post(struct crypt_config *cc, u8 *iv,
598 struct dm_crypt_request *dmreq)
603 if (bio_data_dir(dmreq->ctx->bio_in) == WRITE)
606 dst = kmap_atomic(sg_page(&dmreq->sg_out));
607 r = crypt_iv_lmk_one(cc, iv, dmreq, dst + dmreq->sg_out.offset);
609 /* Tweak the first block of plaintext sector */
611 crypto_xor(dst + dmreq->sg_out.offset, iv, cc->iv_size);
617 static void crypt_iv_tcw_dtr(struct crypt_config *cc)
619 struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
621 kzfree(tcw->iv_seed);
623 kzfree(tcw->whitening);
624 tcw->whitening = NULL;
626 if (tcw->crc32_tfm && !IS_ERR(tcw->crc32_tfm))
627 crypto_free_shash(tcw->crc32_tfm);
628 tcw->crc32_tfm = NULL;
631 static int crypt_iv_tcw_ctr(struct crypt_config *cc, struct dm_target *ti,
634 struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
636 if (cc->key_size <= (cc->iv_size + TCW_WHITENING_SIZE)) {
637 ti->error = "Wrong key size for TCW";
641 tcw->crc32_tfm = crypto_alloc_shash("crc32", 0, 0);
642 if (IS_ERR(tcw->crc32_tfm)) {
643 ti->error = "Error initializing CRC32 in TCW";
644 return PTR_ERR(tcw->crc32_tfm);
647 tcw->iv_seed = kzalloc(cc->iv_size, GFP_KERNEL);
648 tcw->whitening = kzalloc(TCW_WHITENING_SIZE, GFP_KERNEL);
649 if (!tcw->iv_seed || !tcw->whitening) {
650 crypt_iv_tcw_dtr(cc);
651 ti->error = "Error allocating seed storage in TCW";
658 static int crypt_iv_tcw_init(struct crypt_config *cc)
660 struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
661 int key_offset = cc->key_size - cc->iv_size - TCW_WHITENING_SIZE;
663 memcpy(tcw->iv_seed, &cc->key[key_offset], cc->iv_size);
664 memcpy(tcw->whitening, &cc->key[key_offset + cc->iv_size],
670 static int crypt_iv_tcw_wipe(struct crypt_config *cc)
672 struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
674 memset(tcw->iv_seed, 0, cc->iv_size);
675 memset(tcw->whitening, 0, TCW_WHITENING_SIZE);
680 static int crypt_iv_tcw_whitening(struct crypt_config *cc,
681 struct dm_crypt_request *dmreq,
684 struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
685 __le64 sector = cpu_to_le64(dmreq->iv_sector);
686 u8 buf[TCW_WHITENING_SIZE];
687 SHASH_DESC_ON_STACK(desc, tcw->crc32_tfm);
690 /* xor whitening with sector number */
691 memcpy(buf, tcw->whitening, TCW_WHITENING_SIZE);
692 crypto_xor(buf, (u8 *)§or, 8);
693 crypto_xor(&buf[8], (u8 *)§or, 8);
695 /* calculate crc32 for every 32bit part and xor it */
696 desc->tfm = tcw->crc32_tfm;
697 desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
698 for (i = 0; i < 4; i++) {
699 r = crypto_shash_init(desc);
702 r = crypto_shash_update(desc, &buf[i * 4], 4);
705 r = crypto_shash_final(desc, &buf[i * 4]);
709 crypto_xor(&buf[0], &buf[12], 4);
710 crypto_xor(&buf[4], &buf[8], 4);
712 /* apply whitening (8 bytes) to whole sector */
713 for (i = 0; i < ((1 << SECTOR_SHIFT) / 8); i++)
714 crypto_xor(data + i * 8, buf, 8);
716 memzero_explicit(buf, sizeof(buf));
720 static int crypt_iv_tcw_gen(struct crypt_config *cc, u8 *iv,
721 struct dm_crypt_request *dmreq)
723 struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
724 __le64 sector = cpu_to_le64(dmreq->iv_sector);
728 /* Remove whitening from ciphertext */
729 if (bio_data_dir(dmreq->ctx->bio_in) != WRITE) {
730 src = kmap_atomic(sg_page(&dmreq->sg_in));
731 r = crypt_iv_tcw_whitening(cc, dmreq, src + dmreq->sg_in.offset);
736 memcpy(iv, tcw->iv_seed, cc->iv_size);
737 crypto_xor(iv, (u8 *)§or, 8);
739 crypto_xor(&iv[8], (u8 *)§or, cc->iv_size - 8);
744 static int crypt_iv_tcw_post(struct crypt_config *cc, u8 *iv,
745 struct dm_crypt_request *dmreq)
750 if (bio_data_dir(dmreq->ctx->bio_in) != WRITE)
753 /* Apply whitening on ciphertext */
754 dst = kmap_atomic(sg_page(&dmreq->sg_out));
755 r = crypt_iv_tcw_whitening(cc, dmreq, dst + dmreq->sg_out.offset);
761 static struct crypt_iv_operations crypt_iv_plain_ops = {
762 .generator = crypt_iv_plain_gen
765 static struct crypt_iv_operations crypt_iv_plain64_ops = {
766 .generator = crypt_iv_plain64_gen
769 static struct crypt_iv_operations crypt_iv_essiv_ops = {
770 .ctr = crypt_iv_essiv_ctr,
771 .dtr = crypt_iv_essiv_dtr,
772 .init = crypt_iv_essiv_init,
773 .wipe = crypt_iv_essiv_wipe,
774 .generator = crypt_iv_essiv_gen
777 static struct crypt_iv_operations crypt_iv_benbi_ops = {
778 .ctr = crypt_iv_benbi_ctr,
779 .dtr = crypt_iv_benbi_dtr,
780 .generator = crypt_iv_benbi_gen
783 static struct crypt_iv_operations crypt_iv_null_ops = {
784 .generator = crypt_iv_null_gen
787 static struct crypt_iv_operations crypt_iv_lmk_ops = {
788 .ctr = crypt_iv_lmk_ctr,
789 .dtr = crypt_iv_lmk_dtr,
790 .init = crypt_iv_lmk_init,
791 .wipe = crypt_iv_lmk_wipe,
792 .generator = crypt_iv_lmk_gen,
793 .post = crypt_iv_lmk_post
796 static struct crypt_iv_operations crypt_iv_tcw_ops = {
797 .ctr = crypt_iv_tcw_ctr,
798 .dtr = crypt_iv_tcw_dtr,
799 .init = crypt_iv_tcw_init,
800 .wipe = crypt_iv_tcw_wipe,
801 .generator = crypt_iv_tcw_gen,
802 .post = crypt_iv_tcw_post
805 static void crypt_convert_init(struct crypt_config *cc,
806 struct convert_context *ctx,
807 struct bio *bio_out, struct bio *bio_in,
810 ctx->bio_in = bio_in;
811 ctx->bio_out = bio_out;
813 ctx->iter_in = bio_in->bi_iter;
815 ctx->iter_out = bio_out->bi_iter;
816 ctx->cc_sector = sector + cc->iv_offset;
817 init_completion(&ctx->restart);
820 static struct dm_crypt_request *dmreq_of_req(struct crypt_config *cc,
821 struct skcipher_request *req)
823 return (struct dm_crypt_request *)((char *)req + cc->dmreq_start);
826 static struct skcipher_request *req_of_dmreq(struct crypt_config *cc,
827 struct dm_crypt_request *dmreq)
829 return (struct skcipher_request *)((char *)dmreq - cc->dmreq_start);
832 static u8 *iv_of_dmreq(struct crypt_config *cc,
833 struct dm_crypt_request *dmreq)
835 return (u8 *)ALIGN((unsigned long)(dmreq + 1),
836 crypto_skcipher_alignmask(any_tfm(cc)) + 1);
839 static int crypt_convert_block(struct crypt_config *cc,
840 struct convert_context *ctx,
841 struct skcipher_request *req)
843 struct bio_vec bv_in = bio_iter_iovec(ctx->bio_in, ctx->iter_in);
844 struct bio_vec bv_out = bio_iter_iovec(ctx->bio_out, ctx->iter_out);
845 struct dm_crypt_request *dmreq;
849 dmreq = dmreq_of_req(cc, req);
850 iv = iv_of_dmreq(cc, dmreq);
852 dmreq->iv_sector = ctx->cc_sector;
854 sg_init_table(&dmreq->sg_in, 1);
855 sg_set_page(&dmreq->sg_in, bv_in.bv_page, 1 << SECTOR_SHIFT,
858 sg_init_table(&dmreq->sg_out, 1);
859 sg_set_page(&dmreq->sg_out, bv_out.bv_page, 1 << SECTOR_SHIFT,
862 bio_advance_iter(ctx->bio_in, &ctx->iter_in, 1 << SECTOR_SHIFT);
863 bio_advance_iter(ctx->bio_out, &ctx->iter_out, 1 << SECTOR_SHIFT);
865 if (cc->iv_gen_ops) {
866 r = cc->iv_gen_ops->generator(cc, iv, dmreq);
871 skcipher_request_set_crypt(req, &dmreq->sg_in, &dmreq->sg_out,
872 1 << SECTOR_SHIFT, iv);
874 if (bio_data_dir(ctx->bio_in) == WRITE)
875 r = crypto_skcipher_encrypt(req);
877 r = crypto_skcipher_decrypt(req);
879 if (!r && cc->iv_gen_ops && cc->iv_gen_ops->post)
880 r = cc->iv_gen_ops->post(cc, iv, dmreq);
885 static void kcryptd_async_done(struct crypto_async_request *async_req,
888 static void crypt_alloc_req(struct crypt_config *cc,
889 struct convert_context *ctx)
891 unsigned key_index = ctx->cc_sector & (cc->tfms_count - 1);
894 ctx->req = mempool_alloc(cc->req_pool, GFP_NOIO);
896 skcipher_request_set_tfm(ctx->req, cc->tfms[key_index]);
899 * Use REQ_MAY_BACKLOG so a cipher driver internally backlogs
900 * requests if driver request queue is full.
902 skcipher_request_set_callback(ctx->req,
903 CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
904 kcryptd_async_done, dmreq_of_req(cc, ctx->req));
907 static void crypt_free_req(struct crypt_config *cc,
908 struct skcipher_request *req, struct bio *base_bio)
910 struct dm_crypt_io *io = dm_per_bio_data(base_bio, cc->per_bio_data_size);
912 if ((struct skcipher_request *)(io + 1) != req)
913 mempool_free(req, cc->req_pool);
917 * Encrypt / decrypt data from one bio to another one (can be the same one)
919 static int crypt_convert(struct crypt_config *cc,
920 struct convert_context *ctx)
924 atomic_set(&ctx->cc_pending, 1);
926 while (ctx->iter_in.bi_size && ctx->iter_out.bi_size) {
928 crypt_alloc_req(cc, ctx);
930 atomic_inc(&ctx->cc_pending);
932 r = crypt_convert_block(cc, ctx, ctx->req);
936 * The request was queued by a crypto driver
937 * but the driver request queue is full, let's wait.
940 wait_for_completion(&ctx->restart);
941 reinit_completion(&ctx->restart);
944 * The request is queued and processed asynchronously,
945 * completion function kcryptd_async_done() will be called.
952 * The request was already processed (synchronously).
955 atomic_dec(&ctx->cc_pending);
960 /* There was an error while processing the request. */
962 atomic_dec(&ctx->cc_pending);
970 static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone);
973 * Generate a new unfragmented bio with the given size
974 * This should never violate the device limitations (but only because
975 * max_segment_size is being constrained to PAGE_SIZE).
977 * This function may be called concurrently. If we allocate from the mempool
978 * concurrently, there is a possibility of deadlock. For example, if we have
979 * mempool of 256 pages, two processes, each wanting 256, pages allocate from
980 * the mempool concurrently, it may deadlock in a situation where both processes
981 * have allocated 128 pages and the mempool is exhausted.
983 * In order to avoid this scenario we allocate the pages under a mutex.
985 * In order to not degrade performance with excessive locking, we try
986 * non-blocking allocations without a mutex first but on failure we fallback
987 * to blocking allocations with a mutex.
989 static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size)
991 struct crypt_config *cc = io->cc;
993 unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
994 gfp_t gfp_mask = GFP_NOWAIT | __GFP_HIGHMEM;
995 unsigned i, len, remaining_size;
997 struct bio_vec *bvec;
1000 if (unlikely(gfp_mask & __GFP_DIRECT_RECLAIM))
1001 mutex_lock(&cc->bio_alloc_lock);
1003 clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs);
1007 clone_init(io, clone);
1009 remaining_size = size;
1011 for (i = 0; i < nr_iovecs; i++) {
1012 page = mempool_alloc(cc->page_pool, gfp_mask);
1014 crypt_free_buffer_pages(cc, clone);
1016 gfp_mask |= __GFP_DIRECT_RECLAIM;
1020 len = (remaining_size > PAGE_SIZE) ? PAGE_SIZE : remaining_size;
1022 bvec = &clone->bi_io_vec[clone->bi_vcnt++];
1023 bvec->bv_page = page;
1025 bvec->bv_offset = 0;
1027 clone->bi_iter.bi_size += len;
1029 remaining_size -= len;
1033 if (unlikely(gfp_mask & __GFP_DIRECT_RECLAIM))
1034 mutex_unlock(&cc->bio_alloc_lock);
1039 static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone)
1044 bio_for_each_segment_all(bv, clone, i) {
1045 BUG_ON(!bv->bv_page);
1046 mempool_free(bv->bv_page, cc->page_pool);
1051 static void crypt_io_init(struct dm_crypt_io *io, struct crypt_config *cc,
1052 struct bio *bio, sector_t sector)
1056 io->sector = sector;
1059 atomic_set(&io->io_pending, 0);
1062 static void crypt_inc_pending(struct dm_crypt_io *io)
1064 atomic_inc(&io->io_pending);
1068 * One of the bios was finished. Check for completion of
1069 * the whole request and correctly clean up the buffer.
1071 static void crypt_dec_pending(struct dm_crypt_io *io)
1073 struct crypt_config *cc = io->cc;
1074 struct bio *base_bio = io->base_bio;
1075 int error = io->error;
1077 if (!atomic_dec_and_test(&io->io_pending))
1081 crypt_free_req(cc, io->ctx.req, base_bio);
1083 base_bio->bi_error = error;
1084 bio_endio(base_bio);
1088 * kcryptd/kcryptd_io:
1090 * Needed because it would be very unwise to do decryption in an
1091 * interrupt context.
1093 * kcryptd performs the actual encryption or decryption.
1095 * kcryptd_io performs the IO submission.
1097 * They must be separated as otherwise the final stages could be
1098 * starved by new requests which can block in the first stages due
1099 * to memory allocation.
1101 * The work is done per CPU global for all dm-crypt instances.
1102 * They should not depend on each other and do not block.
1104 static void crypt_endio(struct bio *clone)
1106 struct dm_crypt_io *io = clone->bi_private;
1107 struct crypt_config *cc = io->cc;
1108 unsigned rw = bio_data_dir(clone);
1112 * free the processed pages
1115 crypt_free_buffer_pages(cc, clone);
1117 error = clone->bi_error;
1120 if (rw == READ && !error) {
1121 kcryptd_queue_crypt(io);
1125 if (unlikely(error))
1128 crypt_dec_pending(io);
1131 static void clone_init(struct dm_crypt_io *io, struct bio *clone)
1133 struct crypt_config *cc = io->cc;
1135 clone->bi_private = io;
1136 clone->bi_end_io = crypt_endio;
1137 clone->bi_bdev = cc->dev->bdev;
1138 clone->bi_opf = io->base_bio->bi_opf;
1141 static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp)
1143 struct crypt_config *cc = io->cc;
1147 * We need the original biovec array in order to decrypt
1148 * the whole bio data *afterwards* -- thanks to immutable
1149 * biovecs we don't need to worry about the block layer
1150 * modifying the biovec array; so leverage bio_clone_fast().
1152 clone = bio_clone_fast(io->base_bio, gfp, cc->bs);
1156 crypt_inc_pending(io);
1158 clone_init(io, clone);
1159 clone->bi_iter.bi_sector = cc->start + io->sector;
1161 generic_make_request(clone);
1165 static void kcryptd_io_read_work(struct work_struct *work)
1167 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
1169 crypt_inc_pending(io);
1170 if (kcryptd_io_read(io, GFP_NOIO))
1171 io->error = -ENOMEM;
1172 crypt_dec_pending(io);
1175 static void kcryptd_queue_read(struct dm_crypt_io *io)
1177 struct crypt_config *cc = io->cc;
1179 INIT_WORK(&io->work, kcryptd_io_read_work);
1180 queue_work(cc->io_queue, &io->work);
1183 static void kcryptd_io_write(struct dm_crypt_io *io)
1185 struct bio *clone = io->ctx.bio_out;
1187 generic_make_request(clone);
1190 #define crypt_io_from_node(node) rb_entry((node), struct dm_crypt_io, rb_node)
1192 static int dmcrypt_write(void *data)
1194 struct crypt_config *cc = data;
1195 struct dm_crypt_io *io;
1198 struct rb_root write_tree;
1199 struct blk_plug plug;
1201 DECLARE_WAITQUEUE(wait, current);
1203 spin_lock_irq(&cc->write_thread_wait.lock);
1206 if (!RB_EMPTY_ROOT(&cc->write_tree))
1209 set_current_state(TASK_INTERRUPTIBLE);
1210 __add_wait_queue(&cc->write_thread_wait, &wait);
1212 spin_unlock_irq(&cc->write_thread_wait.lock);
1214 if (unlikely(kthread_should_stop())) {
1215 set_task_state(current, TASK_RUNNING);
1216 remove_wait_queue(&cc->write_thread_wait, &wait);
1222 set_task_state(current, TASK_RUNNING);
1223 spin_lock_irq(&cc->write_thread_wait.lock);
1224 __remove_wait_queue(&cc->write_thread_wait, &wait);
1225 goto continue_locked;
1228 write_tree = cc->write_tree;
1229 cc->write_tree = RB_ROOT;
1230 spin_unlock_irq(&cc->write_thread_wait.lock);
1232 BUG_ON(rb_parent(write_tree.rb_node));
1235 * Note: we cannot walk the tree here with rb_next because
1236 * the structures may be freed when kcryptd_io_write is called.
1238 blk_start_plug(&plug);
1240 io = crypt_io_from_node(rb_first(&write_tree));
1241 rb_erase(&io->rb_node, &write_tree);
1242 kcryptd_io_write(io);
1243 } while (!RB_EMPTY_ROOT(&write_tree));
1244 blk_finish_plug(&plug);
1249 static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io, int async)
1251 struct bio *clone = io->ctx.bio_out;
1252 struct crypt_config *cc = io->cc;
1253 unsigned long flags;
1255 struct rb_node **rbp, *parent;
1257 if (unlikely(io->error < 0)) {
1258 crypt_free_buffer_pages(cc, clone);
1260 crypt_dec_pending(io);
1264 /* crypt_convert should have filled the clone bio */
1265 BUG_ON(io->ctx.iter_out.bi_size);
1267 clone->bi_iter.bi_sector = cc->start + io->sector;
1269 if (likely(!async) && test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags)) {
1270 generic_make_request(clone);
1274 spin_lock_irqsave(&cc->write_thread_wait.lock, flags);
1275 rbp = &cc->write_tree.rb_node;
1277 sector = io->sector;
1280 if (sector < crypt_io_from_node(parent)->sector)
1281 rbp = &(*rbp)->rb_left;
1283 rbp = &(*rbp)->rb_right;
1285 rb_link_node(&io->rb_node, parent, rbp);
1286 rb_insert_color(&io->rb_node, &cc->write_tree);
1288 wake_up_locked(&cc->write_thread_wait);
1289 spin_unlock_irqrestore(&cc->write_thread_wait.lock, flags);
1292 static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
1294 struct crypt_config *cc = io->cc;
1297 sector_t sector = io->sector;
1301 * Prevent io from disappearing until this function completes.
1303 crypt_inc_pending(io);
1304 crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, sector);
1306 clone = crypt_alloc_buffer(io, io->base_bio->bi_iter.bi_size);
1307 if (unlikely(!clone)) {
1312 io->ctx.bio_out = clone;
1313 io->ctx.iter_out = clone->bi_iter;
1315 sector += bio_sectors(clone);
1317 crypt_inc_pending(io);
1318 r = crypt_convert(cc, &io->ctx);
1321 crypt_finished = atomic_dec_and_test(&io->ctx.cc_pending);
1323 /* Encryption was already finished, submit io now */
1324 if (crypt_finished) {
1325 kcryptd_crypt_write_io_submit(io, 0);
1326 io->sector = sector;
1330 crypt_dec_pending(io);
1333 static void kcryptd_crypt_read_done(struct dm_crypt_io *io)
1335 crypt_dec_pending(io);
1338 static void kcryptd_crypt_read_convert(struct dm_crypt_io *io)
1340 struct crypt_config *cc = io->cc;
1343 crypt_inc_pending(io);
1345 crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio,
1348 r = crypt_convert(cc, &io->ctx);
1352 if (atomic_dec_and_test(&io->ctx.cc_pending))
1353 kcryptd_crypt_read_done(io);
1355 crypt_dec_pending(io);
1358 static void kcryptd_async_done(struct crypto_async_request *async_req,
1361 struct dm_crypt_request *dmreq = async_req->data;
1362 struct convert_context *ctx = dmreq->ctx;
1363 struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx);
1364 struct crypt_config *cc = io->cc;
1367 * A request from crypto driver backlog is going to be processed now,
1368 * finish the completion and continue in crypt_convert().
1369 * (Callback will be called for the second time for this request.)
1371 if (error == -EINPROGRESS) {
1372 complete(&ctx->restart);
1376 if (!error && cc->iv_gen_ops && cc->iv_gen_ops->post)
1377 error = cc->iv_gen_ops->post(cc, iv_of_dmreq(cc, dmreq), dmreq);
1382 crypt_free_req(cc, req_of_dmreq(cc, dmreq), io->base_bio);
1384 if (!atomic_dec_and_test(&ctx->cc_pending))
1387 if (bio_data_dir(io->base_bio) == READ)
1388 kcryptd_crypt_read_done(io);
1390 kcryptd_crypt_write_io_submit(io, 1);
1393 static void kcryptd_crypt(struct work_struct *work)
1395 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
1397 if (bio_data_dir(io->base_bio) == READ)
1398 kcryptd_crypt_read_convert(io);
1400 kcryptd_crypt_write_convert(io);
1403 static void kcryptd_queue_crypt(struct dm_crypt_io *io)
1405 struct crypt_config *cc = io->cc;
1407 INIT_WORK(&io->work, kcryptd_crypt);
1408 queue_work(cc->crypt_queue, &io->work);
1412 * Decode key from its hex representation
1414 static int crypt_decode_key(u8 *key, char *hex, unsigned int size)
1421 for (i = 0; i < size; i++) {
1425 if (kstrtou8(buffer, 16, &key[i]))
1435 static void crypt_free_tfms(struct crypt_config *cc)
1442 for (i = 0; i < cc->tfms_count; i++)
1443 if (cc->tfms[i] && !IS_ERR(cc->tfms[i])) {
1444 crypto_free_skcipher(cc->tfms[i]);
1452 static int crypt_alloc_tfms(struct crypt_config *cc, char *ciphermode)
1457 cc->tfms = kzalloc(cc->tfms_count * sizeof(struct crypto_skcipher *),
1462 for (i = 0; i < cc->tfms_count; i++) {
1463 cc->tfms[i] = crypto_alloc_skcipher(ciphermode, 0, 0);
1464 if (IS_ERR(cc->tfms[i])) {
1465 err = PTR_ERR(cc->tfms[i]);
1466 crypt_free_tfms(cc);
1474 static int crypt_setkey_allcpus(struct crypt_config *cc)
1476 unsigned subkey_size;
1479 /* Ignore extra keys (which are used for IV etc) */
1480 subkey_size = (cc->key_size - cc->key_extra_size) >> ilog2(cc->tfms_count);
1482 for (i = 0; i < cc->tfms_count; i++) {
1483 r = crypto_skcipher_setkey(cc->tfms[i],
1484 cc->key + (i * subkey_size),
1493 static int crypt_set_key(struct crypt_config *cc, char *key)
1496 int key_string_len = strlen(key);
1498 /* The key size may not be changed. */
1499 if (cc->key_size != (key_string_len >> 1))
1502 /* Hyphen (which gives a key_size of zero) means there is no key. */
1503 if (!cc->key_size && strcmp(key, "-"))
1506 if (cc->key_size && crypt_decode_key(cc->key, key, cc->key_size) < 0)
1509 set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
1511 r = crypt_setkey_allcpus(cc);
1514 /* Hex key string not needed after here, so wipe it. */
1515 memset(key, '0', key_string_len);
1520 static int crypt_wipe_key(struct crypt_config *cc)
1522 clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
1523 memset(&cc->key, 0, cc->key_size * sizeof(u8));
1525 return crypt_setkey_allcpus(cc);
1528 static void crypt_dtr(struct dm_target *ti)
1530 struct crypt_config *cc = ti->private;
1537 if (cc->write_thread)
1538 kthread_stop(cc->write_thread);
1541 destroy_workqueue(cc->io_queue);
1542 if (cc->crypt_queue)
1543 destroy_workqueue(cc->crypt_queue);
1545 crypt_free_tfms(cc);
1548 bioset_free(cc->bs);
1550 mempool_destroy(cc->page_pool);
1551 mempool_destroy(cc->req_pool);
1553 if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
1554 cc->iv_gen_ops->dtr(cc);
1557 dm_put_device(ti, cc->dev);
1560 kzfree(cc->cipher_string);
1562 /* Must zero key material before freeing */
1566 static int crypt_ctr_cipher(struct dm_target *ti,
1567 char *cipher_in, char *key)
1569 struct crypt_config *cc = ti->private;
1570 char *tmp, *cipher, *chainmode, *ivmode, *ivopts, *keycount;
1571 char *cipher_api = NULL;
1575 /* Convert to crypto api definition? */
1576 if (strchr(cipher_in, '(')) {
1577 ti->error = "Bad cipher specification";
1581 cc->cipher_string = kstrdup(cipher_in, GFP_KERNEL);
1582 if (!cc->cipher_string)
1586 * Legacy dm-crypt cipher specification
1587 * cipher[:keycount]-mode-iv:ivopts
1590 keycount = strsep(&tmp, "-");
1591 cipher = strsep(&keycount, ":");
1595 else if (sscanf(keycount, "%u%c", &cc->tfms_count, &dummy) != 1 ||
1596 !is_power_of_2(cc->tfms_count)) {
1597 ti->error = "Bad cipher key count specification";
1600 cc->key_parts = cc->tfms_count;
1601 cc->key_extra_size = 0;
1603 cc->cipher = kstrdup(cipher, GFP_KERNEL);
1607 chainmode = strsep(&tmp, "-");
1608 ivopts = strsep(&tmp, "-");
1609 ivmode = strsep(&ivopts, ":");
1612 DMWARN("Ignoring unexpected additional cipher options");
1615 * For compatibility with the original dm-crypt mapping format, if
1616 * only the cipher name is supplied, use cbc-plain.
1618 if (!chainmode || (!strcmp(chainmode, "plain") && !ivmode)) {
1623 if (strcmp(chainmode, "ecb") && !ivmode) {
1624 ti->error = "IV mechanism required";
1628 cipher_api = kmalloc(CRYPTO_MAX_ALG_NAME, GFP_KERNEL);
1632 ret = snprintf(cipher_api, CRYPTO_MAX_ALG_NAME,
1633 "%s(%s)", chainmode, cipher);
1639 /* Allocate cipher */
1640 ret = crypt_alloc_tfms(cc, cipher_api);
1642 ti->error = "Error allocating crypto tfm";
1647 cc->iv_size = crypto_skcipher_ivsize(any_tfm(cc));
1649 /* at least a 64 bit sector number should fit in our buffer */
1650 cc->iv_size = max(cc->iv_size,
1651 (unsigned int)(sizeof(u64) / sizeof(u8)));
1653 DMWARN("Selected cipher does not support IVs");
1657 /* Choose ivmode, see comments at iv code. */
1659 cc->iv_gen_ops = NULL;
1660 else if (strcmp(ivmode, "plain") == 0)
1661 cc->iv_gen_ops = &crypt_iv_plain_ops;
1662 else if (strcmp(ivmode, "plain64") == 0)
1663 cc->iv_gen_ops = &crypt_iv_plain64_ops;
1664 else if (strcmp(ivmode, "essiv") == 0)
1665 cc->iv_gen_ops = &crypt_iv_essiv_ops;
1666 else if (strcmp(ivmode, "benbi") == 0)
1667 cc->iv_gen_ops = &crypt_iv_benbi_ops;
1668 else if (strcmp(ivmode, "null") == 0)
1669 cc->iv_gen_ops = &crypt_iv_null_ops;
1670 else if (strcmp(ivmode, "lmk") == 0) {
1671 cc->iv_gen_ops = &crypt_iv_lmk_ops;
1673 * Version 2 and 3 is recognised according
1674 * to length of provided multi-key string.
1675 * If present (version 3), last key is used as IV seed.
1676 * All keys (including IV seed) are always the same size.
1678 if (cc->key_size % cc->key_parts) {
1680 cc->key_extra_size = cc->key_size / cc->key_parts;
1682 } else if (strcmp(ivmode, "tcw") == 0) {
1683 cc->iv_gen_ops = &crypt_iv_tcw_ops;
1684 cc->key_parts += 2; /* IV + whitening */
1685 cc->key_extra_size = cc->iv_size + TCW_WHITENING_SIZE;
1688 ti->error = "Invalid IV mode";
1692 /* Initialize and set key */
1693 ret = crypt_set_key(cc, key);
1695 ti->error = "Error decoding and setting key";
1700 if (cc->iv_gen_ops && cc->iv_gen_ops->ctr) {
1701 ret = cc->iv_gen_ops->ctr(cc, ti, ivopts);
1703 ti->error = "Error creating IV";
1708 /* Initialize IV (set keys for ESSIV etc) */
1709 if (cc->iv_gen_ops && cc->iv_gen_ops->init) {
1710 ret = cc->iv_gen_ops->init(cc);
1712 ti->error = "Error initialising IV";
1723 ti->error = "Cannot allocate cipher strings";
1728 * Construct an encryption mapping:
1729 * <cipher> <key> <iv_offset> <dev_path> <start>
1731 static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
1733 struct crypt_config *cc;
1734 unsigned int key_size, opt_params;
1735 unsigned long long tmpll;
1737 size_t iv_size_padding;
1738 struct dm_arg_set as;
1739 const char *opt_string;
1742 static struct dm_arg _args[] = {
1743 {0, 3, "Invalid number of feature args"},
1747 ti->error = "Not enough arguments";
1751 key_size = strlen(argv[1]) >> 1;
1753 cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
1755 ti->error = "Cannot allocate encryption context";
1758 cc->key_size = key_size;
1761 ret = crypt_ctr_cipher(ti, argv[0], argv[1]);
1765 cc->dmreq_start = sizeof(struct skcipher_request);
1766 cc->dmreq_start += crypto_skcipher_reqsize(any_tfm(cc));
1767 cc->dmreq_start = ALIGN(cc->dmreq_start, __alignof__(struct dm_crypt_request));
1769 if (crypto_skcipher_alignmask(any_tfm(cc)) < CRYPTO_MINALIGN) {
1770 /* Allocate the padding exactly */
1771 iv_size_padding = -(cc->dmreq_start + sizeof(struct dm_crypt_request))
1772 & crypto_skcipher_alignmask(any_tfm(cc));
1775 * If the cipher requires greater alignment than kmalloc
1776 * alignment, we don't know the exact position of the
1777 * initialization vector. We must assume worst case.
1779 iv_size_padding = crypto_skcipher_alignmask(any_tfm(cc));
1783 cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start +
1784 sizeof(struct dm_crypt_request) + iv_size_padding + cc->iv_size);
1785 if (!cc->req_pool) {
1786 ti->error = "Cannot allocate crypt request mempool";
1790 cc->per_bio_data_size = ti->per_io_data_size =
1791 ALIGN(sizeof(struct dm_crypt_io) + cc->dmreq_start +
1792 sizeof(struct dm_crypt_request) + iv_size_padding + cc->iv_size,
1793 ARCH_KMALLOC_MINALIGN);
1795 cc->page_pool = mempool_create_page_pool(BIO_MAX_PAGES, 0);
1796 if (!cc->page_pool) {
1797 ti->error = "Cannot allocate page mempool";
1801 cc->bs = bioset_create(MIN_IOS, 0);
1803 ti->error = "Cannot allocate crypt bioset";
1807 mutex_init(&cc->bio_alloc_lock);
1810 if (sscanf(argv[2], "%llu%c", &tmpll, &dummy) != 1) {
1811 ti->error = "Invalid iv_offset sector";
1814 cc->iv_offset = tmpll;
1816 ret = dm_get_device(ti, argv[3], dm_table_get_mode(ti->table), &cc->dev);
1818 ti->error = "Device lookup failed";
1823 if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1) {
1824 ti->error = "Invalid device sector";
1832 /* Optional parameters */
1837 ret = dm_read_arg_group(_args, &as, &opt_params, &ti->error);
1842 while (opt_params--) {
1843 opt_string = dm_shift_arg(&as);
1845 ti->error = "Not enough feature arguments";
1849 if (!strcasecmp(opt_string, "allow_discards"))
1850 ti->num_discard_bios = 1;
1852 else if (!strcasecmp(opt_string, "same_cpu_crypt"))
1853 set_bit(DM_CRYPT_SAME_CPU, &cc->flags);
1855 else if (!strcasecmp(opt_string, "submit_from_crypt_cpus"))
1856 set_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags);
1859 ti->error = "Invalid feature arguments";
1866 cc->io_queue = alloc_workqueue("kcryptd_io", WQ_MEM_RECLAIM, 1);
1867 if (!cc->io_queue) {
1868 ti->error = "Couldn't create kcryptd io queue";
1872 if (test_bit(DM_CRYPT_SAME_CPU, &cc->flags))
1873 cc->crypt_queue = alloc_workqueue("kcryptd", WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM, 1);
1875 cc->crypt_queue = alloc_workqueue("kcryptd", WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM | WQ_UNBOUND,
1877 if (!cc->crypt_queue) {
1878 ti->error = "Couldn't create kcryptd queue";
1882 init_waitqueue_head(&cc->write_thread_wait);
1883 cc->write_tree = RB_ROOT;
1885 cc->write_thread = kthread_create(dmcrypt_write, cc, "dmcrypt_write");
1886 if (IS_ERR(cc->write_thread)) {
1887 ret = PTR_ERR(cc->write_thread);
1888 cc->write_thread = NULL;
1889 ti->error = "Couldn't spawn write thread";
1892 wake_up_process(cc->write_thread);
1894 ti->num_flush_bios = 1;
1895 ti->discard_zeroes_data_unsupported = true;
1904 static int crypt_map(struct dm_target *ti, struct bio *bio)
1906 struct dm_crypt_io *io;
1907 struct crypt_config *cc = ti->private;
1910 * If bio is REQ_PREFLUSH or REQ_OP_DISCARD, just bypass crypt queues.
1911 * - for REQ_PREFLUSH device-mapper core ensures that no IO is in-flight
1912 * - for REQ_OP_DISCARD caller must use flush if IO ordering matters
1914 if (unlikely(bio->bi_opf & REQ_PREFLUSH ||
1915 bio_op(bio) == REQ_OP_DISCARD)) {
1916 bio->bi_bdev = cc->dev->bdev;
1917 if (bio_sectors(bio))
1918 bio->bi_iter.bi_sector = cc->start +
1919 dm_target_offset(ti, bio->bi_iter.bi_sector);
1920 return DM_MAPIO_REMAPPED;
1924 * Check if bio is too large, split as needed.
1926 if (unlikely(bio->bi_iter.bi_size > (BIO_MAX_PAGES << PAGE_SHIFT)) &&
1927 bio_data_dir(bio) == WRITE)
1928 dm_accept_partial_bio(bio, ((BIO_MAX_PAGES << PAGE_SHIFT) >> SECTOR_SHIFT));
1930 io = dm_per_bio_data(bio, cc->per_bio_data_size);
1931 crypt_io_init(io, cc, bio, dm_target_offset(ti, bio->bi_iter.bi_sector));
1932 io->ctx.req = (struct skcipher_request *)(io + 1);
1934 if (bio_data_dir(io->base_bio) == READ) {
1935 if (kcryptd_io_read(io, GFP_NOWAIT))
1936 kcryptd_queue_read(io);
1938 kcryptd_queue_crypt(io);
1940 return DM_MAPIO_SUBMITTED;
1943 static void crypt_status(struct dm_target *ti, status_type_t type,
1944 unsigned status_flags, char *result, unsigned maxlen)
1946 struct crypt_config *cc = ti->private;
1948 int num_feature_args = 0;
1951 case STATUSTYPE_INFO:
1955 case STATUSTYPE_TABLE:
1956 DMEMIT("%s ", cc->cipher_string);
1958 if (cc->key_size > 0)
1959 for (i = 0; i < cc->key_size; i++)
1960 DMEMIT("%02x", cc->key[i]);
1964 DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset,
1965 cc->dev->name, (unsigned long long)cc->start);
1967 num_feature_args += !!ti->num_discard_bios;
1968 num_feature_args += test_bit(DM_CRYPT_SAME_CPU, &cc->flags);
1969 num_feature_args += test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags);
1970 if (num_feature_args) {
1971 DMEMIT(" %d", num_feature_args);
1972 if (ti->num_discard_bios)
1973 DMEMIT(" allow_discards");
1974 if (test_bit(DM_CRYPT_SAME_CPU, &cc->flags))
1975 DMEMIT(" same_cpu_crypt");
1976 if (test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags))
1977 DMEMIT(" submit_from_crypt_cpus");
1984 static void crypt_postsuspend(struct dm_target *ti)
1986 struct crypt_config *cc = ti->private;
1988 set_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1991 static int crypt_preresume(struct dm_target *ti)
1993 struct crypt_config *cc = ti->private;
1995 if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) {
1996 DMERR("aborting resume - crypt key is not set.");
2003 static void crypt_resume(struct dm_target *ti)
2005 struct crypt_config *cc = ti->private;
2007 clear_bit(DM_CRYPT_SUSPENDED, &cc->flags);
2010 /* Message interface
2014 static int crypt_message(struct dm_target *ti, unsigned argc, char **argv)
2016 struct crypt_config *cc = ti->private;
2022 if (!strcasecmp(argv[0], "key")) {
2023 if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) {
2024 DMWARN("not suspended during key manipulation.");
2027 if (argc == 3 && !strcasecmp(argv[1], "set")) {
2028 ret = crypt_set_key(cc, argv[2]);
2031 if (cc->iv_gen_ops && cc->iv_gen_ops->init)
2032 ret = cc->iv_gen_ops->init(cc);
2035 if (argc == 2 && !strcasecmp(argv[1], "wipe")) {
2036 if (cc->iv_gen_ops && cc->iv_gen_ops->wipe) {
2037 ret = cc->iv_gen_ops->wipe(cc);
2041 return crypt_wipe_key(cc);
2046 DMWARN("unrecognised message received.");
2050 static int crypt_iterate_devices(struct dm_target *ti,
2051 iterate_devices_callout_fn fn, void *data)
2053 struct crypt_config *cc = ti->private;
2055 return fn(ti, cc->dev, cc->start, ti->len, data);
2058 static void crypt_io_hints(struct dm_target *ti, struct queue_limits *limits)
2061 * Unfortunate constraint that is required to avoid the potential
2062 * for exceeding underlying device's max_segments limits -- due to
2063 * crypt_alloc_buffer() possibly allocating pages for the encryption
2064 * bio that are not as physically contiguous as the original bio.
2066 limits->max_segment_size = PAGE_SIZE;
2069 static struct target_type crypt_target = {
2071 .version = {1, 14, 1},
2072 .module = THIS_MODULE,
2076 .status = crypt_status,
2077 .postsuspend = crypt_postsuspend,
2078 .preresume = crypt_preresume,
2079 .resume = crypt_resume,
2080 .message = crypt_message,
2081 .iterate_devices = crypt_iterate_devices,
2082 .io_hints = crypt_io_hints,
2085 static int __init dm_crypt_init(void)
2089 r = dm_register_target(&crypt_target);
2091 DMERR("register failed %d", r);
2096 static void __exit dm_crypt_exit(void)
2098 dm_unregister_target(&crypt_target);
2101 module_init(dm_crypt_init);
2102 module_exit(dm_crypt_exit);
2104 MODULE_AUTHOR("Jana Saout <jana@saout.de>");
2105 MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption");
2106 MODULE_LICENSE("GPL");