Initial import

1 files changed, 2080 insertions, 0 deletions

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
new file mode 100644
index 000000000..5503e43e5
--- /dev/null
+++ b/drivers/md/dm-crypt.c
@@ -0,0 +1,2080 @@
+/*
+ * Copyright (C) 2003 Jana Saout <jana@saout.de>
+ * Copyright (C) 2004 Clemens Fruhwirth <clemens@endorphin.org>
+ * Copyright (C) 2006-2009 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2013 Milan Broz <gmazyland@gmail.com>
+ *
+ * This file is released under the GPL.
+ */
+
+#include <linux/completion.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/mempool.h>
+#include <linux/slab.h>
+#include <linux/crypto.h>
+#include <linux/workqueue.h>
+#include <linux/kthread.h>
+#include <linux/backing-dev.h>
+#include <linux/atomic.h>
+#include <linux/scatterlist.h>
+#include <linux/rbtree.h>
+#include <asm/page.h>
+#include <asm/unaligned.h>
+#include <crypto/hash.h>
+#include <crypto/md5.h>
+#include <crypto/algapi.h>
+
+#include <linux/device-mapper.h>
+
+#define DM_MSG_PREFIX "crypt"
+
+/*
+ * context holding the current state of a multi-part conversion
+ */
+struct convert_context {
+	struct completion restart;
+	struct bio *bio_in;
+	struct bio *bio_out;
+	struct bvec_iter iter_in;
+	struct bvec_iter iter_out;
+	sector_t cc_sector;
+	atomic_t cc_pending;
+	struct ablkcipher_request *req;
+};
+
+/*
+ * per bio private data
+ */
+struct dm_crypt_io {
+	struct crypt_config *cc;
+	struct bio *base_bio;
+	struct work_struct work;
+
+	struct convert_context ctx;
+
+	atomic_t io_pending;
+	int error;
+	sector_t sector;
+
+	struct rb_node rb_node;
+} CRYPTO_MINALIGN_ATTR;
+
+struct dm_crypt_request {
+	struct convert_context *ctx;
+	struct scatterlist sg_in;
+	struct scatterlist sg_out;
+	sector_t iv_sector;
+};
+
+struct crypt_config;
+
+struct crypt_iv_operations {
+	int (*ctr)(struct crypt_config *cc, struct dm_target *ti,
+		   const char *opts);
+	void (*dtr)(struct crypt_config *cc);
+	int (*init)(struct crypt_config *cc);
+	int (*wipe)(struct crypt_config *cc);
+	int (*generator)(struct crypt_config *cc, u8 *iv,
+			 struct dm_crypt_request *dmreq);
+	int (*post)(struct crypt_config *cc, u8 *iv,
+		    struct dm_crypt_request *dmreq);
+};
+
+struct iv_essiv_private {
+	struct crypto_hash *hash_tfm;
+	u8 *salt;
+};
+
+struct iv_benbi_private {
+	int shift;
+};
+
+#define LMK_SEED_SIZE 64 /* hash + 0 */
+struct iv_lmk_private {
+	struct crypto_shash *hash_tfm;
+	u8 *seed;
+};
+
+#define TCW_WHITENING_SIZE 16
+struct iv_tcw_private {
+	struct crypto_shash *crc32_tfm;
+	u8 *iv_seed;
+	u8 *whitening;
+};
+
+/*
+ * Crypt: maps a linear range of a block device
+ * and encrypts / decrypts at the same time.
+ */
+enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID,
+	     DM_CRYPT_SAME_CPU, DM_CRYPT_NO_OFFLOAD };
+
+/*
+ * The fields in here must be read only after initialization.
+ */
+struct crypt_config {
+	struct dm_dev *dev;
+	sector_t start;
+
+	/*
+	 * pool for per bio private data, crypto requests and
+	 * encryption requeusts/buffer pages
+	 */
+	mempool_t *req_pool;
+	mempool_t *page_pool;
+	struct bio_set *bs;
+	struct mutex bio_alloc_lock;
+
+	struct workqueue_struct *io_queue;
+	struct workqueue_struct *crypt_queue;
+
+	struct task_struct *write_thread;
+	wait_queue_head_t write_thread_wait;
+	struct rb_root write_tree;
+
+	char *cipher;
+	char *cipher_string;
+
+	struct crypt_iv_operations *iv_gen_ops;
+	union {
+		struct iv_essiv_private essiv;
+		struct iv_benbi_private benbi;
+		struct iv_lmk_private lmk;
+		struct iv_tcw_private tcw;
+	} iv_gen_private;
+	sector_t iv_offset;
+	unsigned int iv_size;
+
+	/* ESSIV: struct crypto_cipher *essiv_tfm */
+	void *iv_private;
+	struct crypto_ablkcipher **tfms;
+	unsigned tfms_count;
+
+	/*
+	 * Layout of each crypto request:
+	 *
+	 *   struct ablkcipher_request
+	 *      context
+	 *      padding
+	 *   struct dm_crypt_request
+	 *      padding
+	 *   IV
+	 *
+	 * The padding is added so that dm_crypt_request and the IV are
+	 * correctly aligned.
+	 */
+	unsigned int dmreq_start;
+
+	unsigned int per_bio_data_size;
+
+	unsigned long flags;
+	unsigned int key_size;
+	unsigned int key_parts;      /* independent parts in key buffer */
+	unsigned int key_extra_size; /* additional keys length */
+	u8 key[0];
+};
+
+#define MIN_IOS        16
+
+static void clone_init(struct dm_crypt_io *, struct bio *);
+static void kcryptd_queue_crypt(struct dm_crypt_io *io);
+static u8 *iv_of_dmreq(struct crypt_config *cc, struct dm_crypt_request *dmreq);
+
+/*
+ * Use this to access cipher attributes that are the same for each CPU.
+ */
+static struct crypto_ablkcipher *any_tfm(struct crypt_config *cc)
+{
+	return cc->tfms[0];
+}
+
+/*
+ * Different IV generation algorithms:
+ *
+ * plain: the initial vector is the 32-bit little-endian version of the sector
+ *        number, padded with zeros if necessary.
+ *
+ * plain64: the initial vector is the 64-bit little-endian version of the sector
+ *        number, padded with zeros if necessary.
+ *
+ * essiv: "encrypted sector|salt initial vector", the sector number is
+ *        encrypted with the bulk cipher using a salt as key. The salt
+ *        should be derived from the bulk cipher's key via hashing.
+ *
+ * benbi: the 64-bit "big-endian 'narrow block'-count", starting at 1
+ *        (needed for LRW-32-AES and possible other narrow block modes)
+ *
+ * null: the initial vector is always zero.  Provides compatibility with
+ *       obsolete loop_fish2 devices.  Do not use for new devices.
+ *
+ * lmk:  Compatible implementation of the block chaining mode used
+ *       by the Loop-AES block device encryption system
+ *       designed by Jari Ruusu. See http://loop-aes.sourceforge.net/
+ *       It operates on full 512 byte sectors and uses CBC
+ *       with an IV derived from the sector number, the data and
+ *       optionally extra IV seed.
+ *       This means that after decryption the first block
+ *       of sector must be tweaked according to decrypted data.
+ *       Loop-AES can use three encryption schemes:
+ *         version 1: is plain aes-cbc mode
+ *         version 2: uses 64 multikey scheme with lmk IV generator
+ *         version 3: the same as version 2 with additional IV seed
+ *                   (it uses 65 keys, last key is used as IV seed)
+ *
+ * tcw:  Compatible implementation of the block chaining mode used
+ *       by the TrueCrypt device encryption system (prior to version 4.1).
+ *       For more info see: https://gitlab.com/cryptsetup/cryptsetup/wikis/TrueCryptOnDiskFormat
+ *       It operates on full 512 byte sectors and uses CBC
+ *       with an IV derived from initial key and the sector number.
+ *       In addition, whitening value is applied on every sector, whitening
+ *       is calculated from initial key, sector number and mixed using CRC32.
+ *       Note that this encryption scheme is vulnerable to watermarking attacks
+ *       and should be used for old compatible containers access only.
+ *
+ * plumb: unimplemented, see:
+ * http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454
+ */
+
+static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv,
+			      struct dm_crypt_request *dmreq)
+{
+	memset(iv, 0, cc->iv_size);
+	*(__le32 *)iv = cpu_to_le32(dmreq->iv_sector & 0xffffffff);
+
+	return 0;
+}
+
+static int crypt_iv_plain64_gen(struct crypt_config *cc, u8 *iv,
+				struct dm_crypt_request *dmreq)
+{
+	memset(iv, 0, cc->iv_size);
+	*(__le64 *)iv = cpu_to_le64(dmreq->iv_sector);
+
+	return 0;
+}
+
+/* Initialise ESSIV - compute salt but no local memory allocations */
+static int crypt_iv_essiv_init(struct crypt_config *cc)
+{
+	struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
+	struct hash_desc desc;
+	struct scatterlist sg;
+	struct crypto_cipher *essiv_tfm;
+	int err;
+
+	sg_init_one(&sg, cc->key, cc->key_size);
+	desc.tfm = essiv->hash_tfm;
+	desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
+
+	err = crypto_hash_digest(&desc, &sg, cc->key_size, essiv->salt);
+	if (err)
+		return err;
+
+	essiv_tfm = cc->iv_private;
+
+	err = crypto_cipher_setkey(essiv_tfm, essiv->salt,
+			    crypto_hash_digestsize(essiv->hash_tfm));
+	if (err)
+		return err;
+
+	return 0;
+}
+
+/* Wipe salt and reset key derived from volume key */
+static int crypt_iv_essiv_wipe(struct crypt_config *cc)
+{
+	struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
+	unsigned salt_size = crypto_hash_digestsize(essiv->hash_tfm);
+	struct crypto_cipher *essiv_tfm;
+	int r, err = 0;
+
+	memset(essiv->salt, 0, salt_size);
+
+	essiv_tfm = cc->iv_private;
+	r = crypto_cipher_setkey(essiv_tfm, essiv->salt, salt_size);
+	if (r)
+		err = r;
+
+	return err;
+}
+
+/* Set up per cpu cipher state */
+static struct crypto_cipher *setup_essiv_cpu(struct crypt_config *cc,
+					     struct dm_target *ti,
+					     u8 *salt, unsigned saltsize)
+{
+	struct crypto_cipher *essiv_tfm;
+	int err;
+
+	/* Setup the essiv_tfm with the given salt */
+	essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC);
+	if (IS_ERR(essiv_tfm)) {
+		ti->error = "Error allocating crypto tfm for ESSIV";
+		return essiv_tfm;
+	}
+
+	if (crypto_cipher_blocksize(essiv_tfm) !=
+	    crypto_ablkcipher_ivsize(any_tfm(cc))) {
+		ti->error = "Block size of ESSIV cipher does "
+			    "not match IV size of block cipher";
+		crypto_free_cipher(essiv_tfm);
+		return ERR_PTR(-EINVAL);
+	}
+
+	err = crypto_cipher_setkey(essiv_tfm, salt, saltsize);
+	if (err) {
+		ti->error = "Failed to set key for ESSIV cipher";
+		crypto_free_cipher(essiv_tfm);
+		return ERR_PTR(err);
+	}
+
+	return essiv_tfm;
+}
+
+static void crypt_iv_essiv_dtr(struct crypt_config *cc)
+{
+	struct crypto_cipher *essiv_tfm;
+	struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
+
+	crypto_free_hash(essiv->hash_tfm);
+	essiv->hash_tfm = NULL;
+
+	kzfree(essiv->salt);
+	essiv->salt = NULL;
+
+	essiv_tfm = cc->iv_private;
+
+	if (essiv_tfm)
+		crypto_free_cipher(essiv_tfm);
+
+	cc->iv_private = NULL;
+}
+
+static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,
+			      const char *opts)
+{
+	struct crypto_cipher *essiv_tfm = NULL;
+	struct crypto_hash *hash_tfm = NULL;
+	u8 *salt = NULL;
+	int err;
+
+	if (!opts) {
+		ti->error = "Digest algorithm missing for ESSIV mode";
+		return -EINVAL;
+	}
+
+	/* Allocate hash algorithm */
+	hash_tfm = crypto_alloc_hash(opts, 0, CRYPTO_ALG_ASYNC);
+	if (IS_ERR(hash_tfm)) {
+		ti->error = "Error initializing ESSIV hash";
+		err = PTR_ERR(hash_tfm);
+		goto bad;
+	}
+
+	salt = kzalloc(crypto_hash_digestsize(hash_tfm), GFP_KERNEL);
+	if (!salt) {
+		ti->error = "Error kmallocing salt storage in ESSIV";
+		err = -ENOMEM;
+		goto bad;
+	}
+
+	cc->iv_gen_private.essiv.salt = salt;
+	cc->iv_gen_private.essiv.hash_tfm = hash_tfm;
+
+	essiv_tfm = setup_essiv_cpu(cc, ti, salt,
+				crypto_hash_digestsize(hash_tfm));
+	if (IS_ERR(essiv_tfm)) {
+		crypt_iv_essiv_dtr(cc);
+		return PTR_ERR(essiv_tfm);
+	}
+	cc->iv_private = essiv_tfm;
+
+	return 0;
+
+bad:
+	if (hash_tfm && !IS_ERR(hash_tfm))
+		crypto_free_hash(hash_tfm);
+	kfree(salt);
+	return err;
+}
+
+static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv,
+			      struct dm_crypt_request *dmreq)
+{
+	struct crypto_cipher *essiv_tfm = cc->iv_private;
+
+	memset(iv, 0, cc->iv_size);
+	*(__le64 *)iv = cpu_to_le64(dmreq->iv_sector);
+	crypto_cipher_encrypt_one(essiv_tfm, iv, iv);
+
+	return 0;
+}
+
+static int crypt_iv_benbi_ctr(struct crypt_config *cc, struct dm_target *ti,
+			      const char *opts)
+{
+	unsigned bs = crypto_ablkcipher_blocksize(any_tfm(cc));
+	int log = ilog2(bs);
+
+	/* we need to calculate how far we must shift the sector count
+	 * to get the cipher block count, we use this shift in _gen */
+
+	if (1 << log != bs) {
+		ti->error = "cypher blocksize is not a power of 2";
+		return -EINVAL;
+	}
+
+	if (log > 9) {
+		ti->error = "cypher blocksize is > 512";
+		return -EINVAL;
+	}
+
+	cc->iv_gen_private.benbi.shift = 9 - log;
+
+	return 0;
+}
+
+static void crypt_iv_benbi_dtr(struct crypt_config *cc)
+{
+}
+
+static int crypt_iv_benbi_gen(struct crypt_config *cc, u8 *iv,
+			      struct dm_crypt_request *dmreq)
+{
+	__be64 val;
+
+	memset(iv, 0, cc->iv_size - sizeof(u64)); /* rest is cleared below */
+
+	val = cpu_to_be64(((u64)dmreq->iv_sector << cc->iv_gen_private.benbi.shift) + 1);
+	put_unaligned(val, (__be64 *)(iv + cc->iv_size - sizeof(u64)));
+
+	return 0;
+}
+
+static int crypt_iv_null_gen(struct crypt_config *cc, u8 *iv,
+			     struct dm_crypt_request *dmreq)
+{
+	memset(iv, 0, cc->iv_size);
+
+	return 0;
+}
+
+static void crypt_iv_lmk_dtr(struct crypt_config *cc)
+{
+	struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
+
+	if (lmk->hash_tfm && !IS_ERR(lmk->hash_tfm))
+		crypto_free_shash(lmk->hash_tfm);
+	lmk->hash_tfm = NULL;
+
+	kzfree(lmk->seed);
+	lmk->seed = NULL;
+}
+
+static int crypt_iv_lmk_ctr(struct crypt_config *cc, struct dm_target *ti,
+			    const char *opts)
+{
+	struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
+
+	lmk->hash_tfm = crypto_alloc_shash("md5", 0, 0);
+	if (IS_ERR(lmk->hash_tfm)) {
+		ti->error = "Error initializing LMK hash";
+		return PTR_ERR(lmk->hash_tfm);
+	}
+
+	/* No seed in LMK version 2 */
+	if (cc->key_parts == cc->tfms_count) {
+		lmk->seed = NULL;
+		return 0;
+	}
+
+	lmk->seed = kzalloc(LMK_SEED_SIZE, GFP_KERNEL);
+	if (!lmk->seed) {
+		crypt_iv_lmk_dtr(cc);
+		ti->error = "Error kmallocing seed storage in LMK";
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static int crypt_iv_lmk_init(struct crypt_config *cc)
+{
+	struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
+	int subkey_size = cc->key_size / cc->key_parts;
+
+	/* LMK seed is on the position of LMK_KEYS + 1 key */
+	if (lmk->seed)
+		memcpy(lmk->seed, cc->key + (cc->tfms_count * subkey_size),
+		       crypto_shash_digestsize(lmk->hash_tfm));
+
+	return 0;
+}
+
+static int crypt_iv_lmk_wipe(struct crypt_config *cc)
+{
+	struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
+
+	if (lmk->seed)
+		memset(lmk->seed, 0, LMK_SEED_SIZE);
+
+	return 0;
+}
+
+static int crypt_iv_lmk_one(struct crypt_config *cc, u8 *iv,
+			    struct dm_crypt_request *dmreq,
+			    u8 *data)
+{
+	struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
+	SHASH_DESC_ON_STACK(desc, lmk->hash_tfm);
+	struct md5_state md5state;
+	__le32 buf[4];
+	int i, r;
+
+	desc->tfm = lmk->hash_tfm;
+	desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
+
+	r = crypto_shash_init(desc);
+	if (r)
+		return r;
+
+	if (lmk->seed) {
+		r = crypto_shash_update(desc, lmk->seed, LMK_SEED_SIZE);
+		if (r)
+			return r;
+	}
+
+	/* Sector is always 512B, block size 16, add data of blocks 1-31 */
+	r = crypto_shash_update(desc, data + 16, 16 * 31);
+	if (r)
+		return r;
+
+	/* Sector is cropped to 56 bits here */
+	buf[0] = cpu_to_le32(dmreq->iv_sector & 0xFFFFFFFF);
+	buf[1] = cpu_to_le32((((u64)dmreq->iv_sector >> 32) & 0x00FFFFFF) | 0x80000000);
+	buf[2] = cpu_to_le32(4024);
+	buf[3] = 0;
+	r = crypto_shash_update(desc, (u8 *)buf, sizeof(buf));
+	if (r)
+		return r;
+
+	/* No MD5 padding here */
+	r = crypto_shash_export(desc, &md5state);
+	if (r)
+		return r;
+
+	for (i = 0; i < MD5_HASH_WORDS; i++)
+		__cpu_to_le32s(&md5state.hash[i]);
+	memcpy(iv, &md5state.hash, cc->iv_size);
+
+	return 0;
+}
+
+static int crypt_iv_lmk_gen(struct crypt_config *cc, u8 *iv,
+			    struct dm_crypt_request *dmreq)
+{
+	u8 *src;
+	int r = 0;
+
+	if (bio_data_dir(dmreq->ctx->bio_in) == WRITE) {
+		src = kmap_atomic(sg_page(&dmreq->sg_in));
+		r = crypt_iv_lmk_one(cc, iv, dmreq, src + dmreq->sg_in.offset);
+		kunmap_atomic(src);
+	} else
+		memset(iv, 0, cc->iv_size);
+
+	return r;
+}
+
+static int crypt_iv_lmk_post(struct crypt_config *cc, u8 *iv,
+			     struct dm_crypt_request *dmreq)
+{
+	u8 *dst;
+	int r;
+
+	if (bio_data_dir(dmreq->ctx->bio_in) == WRITE)
+		return 0;
+
+	dst = kmap_atomic(sg_page(&dmreq->sg_out));
+	r = crypt_iv_lmk_one(cc, iv, dmreq, dst + dmreq->sg_out.offset);
+
+	/* Tweak the first block of plaintext sector */
+	if (!r)
+		crypto_xor(dst + dmreq->sg_out.offset, iv, cc->iv_size);
+
+	kunmap_atomic(dst);
+	return r;
+}
+
+static void crypt_iv_tcw_dtr(struct crypt_config *cc)
+{
+	struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
+
+	kzfree(tcw->iv_seed);
+	tcw->iv_seed = NULL;
+	kzfree(tcw->whitening);
+	tcw->whitening = NULL;
+
+	if (tcw->crc32_tfm && !IS_ERR(tcw->crc32_tfm))
+		crypto_free_shash(tcw->crc32_tfm);
+	tcw->crc32_tfm = NULL;
+}
+
+static int crypt_iv_tcw_ctr(struct crypt_config *cc, struct dm_target *ti,
+			    const char *opts)
+{
+	struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
+
+	if (cc->key_size <= (cc->iv_size + TCW_WHITENING_SIZE)) {
+		ti->error = "Wrong key size for TCW";
+		return -EINVAL;
+	}
+
+	tcw->crc32_tfm = crypto_alloc_shash("crc32", 0, 0);
+	if (IS_ERR(tcw->crc32_tfm)) {
+		ti->error = "Error initializing CRC32 in TCW";
+		return PTR_ERR(tcw->crc32_tfm);
+	}
+
+	tcw->iv_seed = kzalloc(cc->iv_size, GFP_KERNEL);
+	tcw->whitening = kzalloc(TCW_WHITENING_SIZE, GFP_KERNEL);
+	if (!tcw->iv_seed || !tcw->whitening) {
+		crypt_iv_tcw_dtr(cc);
+		ti->error = "Error allocating seed storage in TCW";
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static int crypt_iv_tcw_init(struct crypt_config *cc)
+{
+	struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
+	int key_offset = cc->key_size - cc->iv_size - TCW_WHITENING_SIZE;
+
+	memcpy(tcw->iv_seed, &cc->key[key_offset], cc->iv_size);
+	memcpy(tcw->whitening, &cc->key[key_offset + cc->iv_size],
+	       TCW_WHITENING_SIZE);
+
+	return 0;
+}
+
+static int crypt_iv_tcw_wipe(struct crypt_config *cc)
+{
+	struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
+
+	memset(tcw->iv_seed, 0, cc->iv_size);
+	memset(tcw->whitening, 0, TCW_WHITENING_SIZE);
+
+	return 0;
+}
+
+static int crypt_iv_tcw_whitening(struct crypt_config *cc,
+				  struct dm_crypt_request *dmreq,
+				  u8 *data)
+{
+	struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
+	u64 sector = cpu_to_le64((u64)dmreq->iv_sector);
+	u8 buf[TCW_WHITENING_SIZE];
+	SHASH_DESC_ON_STACK(desc, tcw->crc32_tfm);
+	int i, r;
+
+	/* xor whitening with sector number */
+	memcpy(buf, tcw->whitening, TCW_WHITENING_SIZE);
+	crypto_xor(buf, (u8 *)&sector, 8);
+	crypto_xor(&buf[8], (u8 *)&sector, 8);
+
+	/* calculate crc32 for every 32bit part and xor it */
+	desc->tfm = tcw->crc32_tfm;
+	desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
+	for (i = 0; i < 4; i++) {
+		r = crypto_shash_init(desc);
+		if (r)
+			goto out;
+		r = crypto_shash_update(desc, &buf[i * 4], 4);
+		if (r)
+			goto out;
+		r = crypto_shash_final(desc, &buf[i * 4]);
+		if (r)
+			goto out;
+	}
+	crypto_xor(&buf[0], &buf[12], 4);
+	crypto_xor(&buf[4], &buf[8], 4);
+
+	/* apply whitening (8 bytes) to whole sector */
+	for (i = 0; i < ((1 << SECTOR_SHIFT) / 8); i++)
+		crypto_xor(data + i * 8, buf, 8);
+out:
+	memzero_explicit(buf, sizeof(buf));
+	return r;
+}
+
+static int crypt_iv_tcw_gen(struct crypt_config *cc, u8 *iv,
+			    struct dm_crypt_request *dmreq)
+{
+	struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
+	u64 sector = cpu_to_le64((u64)dmreq->iv_sector);
+	u8 *src;
+	int r = 0;
+
+	/* Remove whitening from ciphertext */
+	if (bio_data_dir(dmreq->ctx->bio_in) != WRITE) {
+		src = kmap_atomic(sg_page(&dmreq->sg_in));
+		r = crypt_iv_tcw_whitening(cc, dmreq, src + dmreq->sg_in.offset);
+		kunmap_atomic(src);
+	}
+
+	/* Calculate IV */
+	memcpy(iv, tcw->iv_seed, cc->iv_size);
+	crypto_xor(iv, (u8 *)&sector, 8);
+	if (cc->iv_size > 8)
+		crypto_xor(&iv[8], (u8 *)&sector, cc->iv_size - 8);
+
+	return r;
+}
+
+static int crypt_iv_tcw_post(struct crypt_config *cc, u8 *iv,
+			     struct dm_crypt_request *dmreq)
+{
+	u8 *dst;
+	int r;
+
+	if (bio_data_dir(dmreq->ctx->bio_in) != WRITE)
+		return 0;
+
+	/* Apply whitening on ciphertext */
+	dst = kmap_atomic(sg_page(&dmreq->sg_out));
+	r = crypt_iv_tcw_whitening(cc, dmreq, dst + dmreq->sg_out.offset);
+	kunmap_atomic(dst);
+
+	return r;
+}
+
+static struct crypt_iv_operations crypt_iv_plain_ops = {
+	.generator = crypt_iv_plain_gen
+};
+
+static struct crypt_iv_operations crypt_iv_plain64_ops = {
+	.generator = crypt_iv_plain64_gen
+};
+
+static struct crypt_iv_operations crypt_iv_essiv_ops = {
+	.ctr       = crypt_iv_essiv_ctr,
+	.dtr       = crypt_iv_essiv_dtr,
+	.init      = crypt_iv_essiv_init,
+	.wipe      = crypt_iv_essiv_wipe,
+	.generator = crypt_iv_essiv_gen
+};
+
+static struct crypt_iv_operations crypt_iv_benbi_ops = {
+	.ctr	   = crypt_iv_benbi_ctr,
+	.dtr	   = crypt_iv_benbi_dtr,
+	.generator = crypt_iv_benbi_gen
+};
+
+static struct crypt_iv_operations crypt_iv_null_ops = {
+	.generator = crypt_iv_null_gen
+};
+
+static struct crypt_iv_operations crypt_iv_lmk_ops = {
+	.ctr	   = crypt_iv_lmk_ctr,
+	.dtr	   = crypt_iv_lmk_dtr,
+	.init	   = crypt_iv_lmk_init,
+	.wipe	   = crypt_iv_lmk_wipe,
+	.generator = crypt_iv_lmk_gen,
+	.post	   = crypt_iv_lmk_post
+};
+
+static struct crypt_iv_operations crypt_iv_tcw_ops = {
+	.ctr	   = crypt_iv_tcw_ctr,
+	.dtr	   = crypt_iv_tcw_dtr,
+	.init	   = crypt_iv_tcw_init,
+	.wipe	   = crypt_iv_tcw_wipe,
+	.generator = crypt_iv_tcw_gen,
+	.post	   = crypt_iv_tcw_post
+};
+
+static void crypt_convert_init(struct crypt_config *cc,
+			       struct convert_context *ctx,
+			       struct bio *bio_out, struct bio *bio_in,
+			       sector_t sector)
+{
+	ctx->bio_in = bio_in;
+	ctx->bio_out = bio_out;
+	if (bio_in)
+		ctx->iter_in = bio_in->bi_iter;
+	if (bio_out)
+		ctx->iter_out = bio_out->bi_iter;
+	ctx->cc_sector = sector + cc->iv_offset;
+	init_completion(&ctx->restart);
+}
+
+static struct dm_crypt_request *dmreq_of_req(struct crypt_config *cc,
+					     struct ablkcipher_request *req)
+{
+	return (struct dm_crypt_request *)((char *)req + cc->dmreq_start);
+}
+
+static struct ablkcipher_request *req_of_dmreq(struct crypt_config *cc,
+					       struct dm_crypt_request *dmreq)
+{
+	return (struct ablkcipher_request *)((char *)dmreq - cc->dmreq_start);
+}
+
+static u8 *iv_of_dmreq(struct crypt_config *cc,
+		       struct dm_crypt_request *dmreq)
+{
+	return (u8 *)ALIGN((unsigned long)(dmreq + 1),
+		crypto_ablkcipher_alignmask(any_tfm(cc)) + 1);
+}
+
+static int crypt_convert_block(struct crypt_config *cc,
+			       struct convert_context *ctx,
+			       struct ablkcipher_request *req)
+{
+	struct bio_vec bv_in = bio_iter_iovec(ctx->bio_in, ctx->iter_in);
+	struct bio_vec bv_out = bio_iter_iovec(ctx->bio_out, ctx->iter_out);
+	struct dm_crypt_request *dmreq;
+	u8 *iv;
+	int r;
+
+	dmreq = dmreq_of_req(cc, req);
+	iv = iv_of_dmreq(cc, dmreq);
+
+	dmreq->iv_sector = ctx->cc_sector;
+	dmreq->ctx = ctx;
+	sg_init_table(&dmreq->sg_in, 1);
+	sg_set_page(&dmreq->sg_in, bv_in.bv_page, 1 << SECTOR_SHIFT,
+		    bv_in.bv_offset);
+
+	sg_init_table(&dmreq->sg_out, 1);
+	sg_set_page(&dmreq->sg_out, bv_out.bv_page, 1 << SECTOR_SHIFT,
+		    bv_out.bv_offset);
+
+	bio_advance_iter(ctx->bio_in, &ctx->iter_in, 1 << SECTOR_SHIFT);
+	bio_advance_iter(ctx->bio_out, &ctx->iter_out, 1 << SECTOR_SHIFT);
+
+	if (cc->iv_gen_ops) {
+		r = cc->iv_gen_ops->generator(cc, iv, dmreq);
+		if (r < 0)
+			return r;
+	}
+
+	ablkcipher_request_set_crypt(req, &dmreq->sg_in, &dmreq->sg_out,
+				     1 << SECTOR_SHIFT, iv);
+
+	if (bio_data_dir(ctx->bio_in) == WRITE)
+		r = crypto_ablkcipher_encrypt(req);
+	else
+		r = crypto_ablkcipher_decrypt(req);
+
+	if (!r && cc->iv_gen_ops && cc->iv_gen_ops->post)
+		r = cc->iv_gen_ops->post(cc, iv, dmreq);
+
+	return r;
+}
+
+static void kcryptd_async_done(struct crypto_async_request *async_req,
+			       int error);
+
+static void crypt_alloc_req(struct crypt_config *cc,
+			    struct convert_context *ctx)
+{
+	unsigned key_index = ctx->cc_sector & (cc->tfms_count - 1);
+
+	if (!ctx->req)
+		ctx->req = mempool_alloc(cc->req_pool, GFP_NOIO);
+
+	ablkcipher_request_set_tfm(ctx->req, cc->tfms[key_index]);
+	ablkcipher_request_set_callback(ctx->req,
+	    CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
+	    kcryptd_async_done, dmreq_of_req(cc, ctx->req));
+}
+
+static void crypt_free_req(struct crypt_config *cc,
+			   struct ablkcipher_request *req, struct bio *base_bio)
+{
+	struct dm_crypt_io *io = dm_per_bio_data(base_bio, cc->per_bio_data_size);
+
+	if ((struct ablkcipher_request *)(io + 1) != req)
+		mempool_free(req, cc->req_pool);
+}
+
+/*
+ * Encrypt / decrypt data from one bio to another one (can be the same one)
+ */
+static int crypt_convert(struct crypt_config *cc,
+			 struct convert_context *ctx)
+{
+	int r;
+
+	atomic_set(&ctx->cc_pending, 1);
+
+	while (ctx->iter_in.bi_size && ctx->iter_out.bi_size) {
+
+		crypt_alloc_req(cc, ctx);
+
+		atomic_inc(&ctx->cc_pending);
+
+		r = crypt_convert_block(cc, ctx, ctx->req);
+
+		switch (r) {
+		/* async */
+		case -EBUSY:
+			wait_for_completion(&ctx->restart);
+			reinit_completion(&ctx->restart);
+			/* fall through*/
+		case -EINPROGRESS:
+			ctx->req = NULL;
+			ctx->cc_sector++;
+			continue;
+
+		/* sync */
+		case 0:
+			atomic_dec(&ctx->cc_pending);
+			ctx->cc_sector++;
+			cond_resched();
+			continue;
+
+		/* error */
+		default:
+			atomic_dec(&ctx->cc_pending);
+			return r;
+		}
+	}
+
+	return 0;
+}
+
+static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone);
+
+/*
+ * Generate a new unfragmented bio with the given size
+ * This should never violate the device limitations
+ *
+ * This function may be called concurrently. If we allocate from the mempool
+ * concurrently, there is a possibility of deadlock. For example, if we have
+ * mempool of 256 pages, two processes, each wanting 256, pages allocate from
+ * the mempool concurrently, it may deadlock in a situation where both processes
+ * have allocated 128 pages and the mempool is exhausted.
+ *
+ * In order to avoid this scenario we allocate the pages under a mutex.
+ *
+ * In order to not degrade performance with excessive locking, we try
+ * non-blocking allocations without a mutex first but on failure we fallback
+ * to blocking allocations with a mutex.
+ */
+static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size)
+{
+	struct crypt_config *cc = io->cc;
+	struct bio *clone;
+	unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
+	gfp_t gfp_mask = GFP_NOWAIT | __GFP_HIGHMEM;
+	unsigned i, len, remaining_size;
+	struct page *page;
+	struct bio_vec *bvec;
+
+retry:
+	if (unlikely(gfp_mask & __GFP_WAIT))
+		mutex_lock(&cc->bio_alloc_lock);
+
+	clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs);
+	if (!clone)
+		goto return_clone;
+
+	clone_init(io, clone);
+
+	remaining_size = size;
+
+	for (i = 0; i < nr_iovecs; i++) {
+		page = mempool_alloc(cc->page_pool, gfp_mask);
+		if (!page) {
+			crypt_free_buffer_pages(cc, clone);
+			bio_put(clone);
+			gfp_mask |= __GFP_WAIT;
+			goto retry;
+		}
+
+		len = (remaining_size > PAGE_SIZE) ? PAGE_SIZE : remaining_size;
+
+		bvec = &clone->bi_io_vec[clone->bi_vcnt++];
+		bvec->bv_page = page;
+		bvec->bv_len = len;
+		bvec->bv_offset = 0;
+
+		clone->bi_iter.bi_size += len;
+
+		remaining_size -= len;
+	}
+
+return_clone:
+	if (unlikely(gfp_mask & __GFP_WAIT))
+		mutex_unlock(&cc->bio_alloc_lock);
+
+	return clone;
+}
+
+static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone)
+{
+	unsigned int i;
+	struct bio_vec *bv;
+
+	bio_for_each_segment_all(bv, clone, i) {
+		BUG_ON(!bv->bv_page);
+		mempool_free(bv->bv_page, cc->page_pool);
+		bv->bv_page = NULL;
+	}
+}
+
+static void crypt_io_init(struct dm_crypt_io *io, struct crypt_config *cc,
+			  struct bio *bio, sector_t sector)
+{
+	io->cc = cc;
+	io->base_bio = bio;
+	io->sector = sector;
+	io->error = 0;
+	io->ctx.req = NULL;
+	atomic_set(&io->io_pending, 0);
+}
+
+static void crypt_inc_pending(struct dm_crypt_io *io)
+{
+	atomic_inc(&io->io_pending);
+}
+
+/*
+ * One of the bios was finished. Check for completion of
+ * the whole request and correctly clean up the buffer.
+ */
+static void crypt_dec_pending(struct dm_crypt_io *io)
+{
+	struct crypt_config *cc = io->cc;
+	struct bio *base_bio = io->base_bio;
+	int error = io->error;
+
+	if (!atomic_dec_and_test(&io->io_pending))
+		return;
+
+	if (io->ctx.req)
+		crypt_free_req(cc, io->ctx.req, base_bio);
+
+	bio_endio(base_bio, error);
+}
+
+/*
+ * kcryptd/kcryptd_io:
+ *
+ * Needed because it would be very unwise to do decryption in an
+ * interrupt context.
+ *
+ * kcryptd performs the actual encryption or decryption.
+ *
+ * kcryptd_io performs the IO submission.
+ *
+ * They must be separated as otherwise the final stages could be
+ * starved by new requests which can block in the first stages due
+ * to memory allocation.
+ *
+ * The work is done per CPU global for all dm-crypt instances.
+ * They should not depend on each other and do not block.
+ */
+static void crypt_endio(struct bio *clone, int error)
+{
+	struct dm_crypt_io *io = clone->bi_private;
+	struct crypt_config *cc = io->cc;
+	unsigned rw = bio_data_dir(clone);
+
+	if (unlikely(!bio_flagged(clone, BIO_UPTODATE) && !error))
+		error = -EIO;
+
+	/*
+	 * free the processed pages
+	 */
+	if (rw == WRITE)
+		crypt_free_buffer_pages(cc, clone);
+
+	bio_put(clone);
+
+	if (rw == READ && !error) {
+		kcryptd_queue_crypt(io);
+		return;
+	}
+
+	if (unlikely(error))
+		io->error = error;
+
+	crypt_dec_pending(io);
+}
+
+static void clone_init(struct dm_crypt_io *io, struct bio *clone)
+{
+	struct crypt_config *cc = io->cc;
+
+	clone->bi_private = io;
+	clone->bi_end_io  = crypt_endio;
+	clone->bi_bdev    = cc->dev->bdev;
+	clone->bi_rw      = io->base_bio->bi_rw;
+}
+
+static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp)
+{
+	struct crypt_config *cc = io->cc;
+	struct bio *clone;
+
+	/*
+	 * We need the original biovec array in order to decrypt
+	 * the whole bio data *afterwards* -- thanks to immutable
+	 * biovecs we don't need to worry about the block layer
+	 * modifying the biovec array; so leverage bio_clone_fast().
+	 */
+	clone = bio_clone_fast(io->base_bio, gfp, cc->bs);
+	if (!clone)
+		return 1;
+
+	crypt_inc_pending(io);
+
+	clone_init(io, clone);
+	clone->bi_iter.bi_sector = cc->start + io->sector;
+
+	generic_make_request(clone);
+	return 0;
+}
+
+static void kcryptd_io_read_work(struct work_struct *work)
+{
+	struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
+
+	crypt_inc_pending(io);
+	if (kcryptd_io_read(io, GFP_NOIO))
+		io->error = -ENOMEM;
+	crypt_dec_pending(io);
+}
+
+static void kcryptd_queue_read(struct dm_crypt_io *io)
+{
+	struct crypt_config *cc = io->cc;
+
+	INIT_WORK(&io->work, kcryptd_io_read_work);
+	queue_work(cc->io_queue, &io->work);
+}
+
+static void kcryptd_io_write(struct dm_crypt_io *io)
+{
+	struct bio *clone = io->ctx.bio_out;
+
+	generic_make_request(clone);
+}
+
+#define crypt_io_from_node(node) rb_entry((node), struct dm_crypt_io, rb_node)
+
+static int dmcrypt_write(void *data)
+{
+	struct crypt_config *cc = data;
+	struct dm_crypt_io *io;
+
+	while (1) {
+		struct rb_root write_tree;
+		struct blk_plug plug;
+
+		DECLARE_WAITQUEUE(wait, current);
+
+		spin_lock_irq(&cc->write_thread_wait.lock);
+continue_locked:
+
+		if (!RB_EMPTY_ROOT(&cc->write_tree))
+			goto pop_from_list;
+
+		__set_current_state(TASK_INTERRUPTIBLE);
+		__add_wait_queue(&cc->write_thread_wait, &wait);
+
+		spin_unlock_irq(&cc->write_thread_wait.lock);
+
+		if (unlikely(kthread_should_stop())) {
+			set_task_state(current, TASK_RUNNING);
+			remove_wait_queue(&cc->write_thread_wait, &wait);
+			break;
+		}
+
+		schedule();
+
+		set_task_state(current, TASK_RUNNING);
+		spin_lock_irq(&cc->write_thread_wait.lock);
+		__remove_wait_queue(&cc->write_thread_wait, &wait);
+		goto continue_locked;
+
+pop_from_list:
+		write_tree = cc->write_tree;
+		cc->write_tree = RB_ROOT;
+		spin_unlock_irq(&cc->write_thread_wait.lock);
+
+		BUG_ON(rb_parent(write_tree.rb_node));
+
+		/*
+		 * Note: we cannot walk the tree here with rb_next because
+		 * the structures may be freed when kcryptd_io_write is called.
+		 */
+		blk_start_plug(&plug);
+		do {
+			io = crypt_io_from_node(rb_first(&write_tree));
+			rb_erase(&io->rb_node, &write_tree);
+			kcryptd_io_write(io);
+		} while (!RB_EMPTY_ROOT(&write_tree));
+		blk_finish_plug(&plug);
+	}
+	return 0;
+}
+
+static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io, int async)
+{
+	struct bio *clone = io->ctx.bio_out;
+	struct crypt_config *cc = io->cc;
+	unsigned long flags;
+	sector_t sector;
+	struct rb_node **rbp, *parent;
+
+	if (unlikely(io->error < 0)) {
+		crypt_free_buffer_pages(cc, clone);
+		bio_put(clone);
+		crypt_dec_pending(io);
+		return;
+	}
+
+	/* crypt_convert should have filled the clone bio */
+	BUG_ON(io->ctx.iter_out.bi_size);
+
+	clone->bi_iter.bi_sector = cc->start + io->sector;
+
+	if (likely(!async) && test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags)) {
+		generic_make_request(clone);
+		return;
+	}
+
+	spin_lock_irqsave(&cc->write_thread_wait.lock, flags);
+	rbp = &cc->write_tree.rb_node;
+	parent = NULL;
+	sector = io->sector;
+	while (*rbp) {
+		parent = *rbp;
+		if (sector < crypt_io_from_node(parent)->sector)
+			rbp = &(*rbp)->rb_left;
+		else
+			rbp = &(*rbp)->rb_right;
+	}
+	rb_link_node(&io->rb_node, parent, rbp);
+	rb_insert_color(&io->rb_node, &cc->write_tree);
+
+	wake_up_locked(&cc->write_thread_wait);
+	spin_unlock_irqrestore(&cc->write_thread_wait.lock, flags);
+}
+
+static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
+{
+	struct crypt_config *cc = io->cc;
+	struct bio *clone;
+	int crypt_finished;
+	sector_t sector = io->sector;
+	int r;
+
+	/*
+	 * Prevent io from disappearing until this function completes.
+	 */
+	crypt_inc_pending(io);
+	crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, sector);
+
+	clone = crypt_alloc_buffer(io, io->base_bio->bi_iter.bi_size);
+	if (unlikely(!clone)) {
+		io->error = -EIO;
+		goto dec;
+	}
+
+	io->ctx.bio_out = clone;
+	io->ctx.iter_out = clone->bi_iter;
+
+	sector += bio_sectors(clone);
+
+	crypt_inc_pending(io);
+	r = crypt_convert(cc, &io->ctx);
+	if (r)
+		io->error = -EIO;
+	crypt_finished = atomic_dec_and_test(&io->ctx.cc_pending);
+
+	/* Encryption was already finished, submit io now */
+	if (crypt_finished) {
+		kcryptd_crypt_write_io_submit(io, 0);
+		io->sector = sector;
+	}
+
+dec:
+	crypt_dec_pending(io);
+}
+
+static void kcryptd_crypt_read_done(struct dm_crypt_io *io)
+{
+	crypt_dec_pending(io);
+}
+
+static void kcryptd_crypt_read_convert(struct dm_crypt_io *io)
+{
+	struct crypt_config *cc = io->cc;
+	int r = 0;
+
+	crypt_inc_pending(io);
+
+	crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio,
+			   io->sector);
+
+	r = crypt_convert(cc, &io->ctx);
+	if (r < 0)
+		io->error = -EIO;
+
+	if (atomic_dec_and_test(&io->ctx.cc_pending))
+		kcryptd_crypt_read_done(io);
+
+	crypt_dec_pending(io);
+}
+
+static void kcryptd_async_done(struct crypto_async_request *async_req,
+			       int error)
+{
+	struct dm_crypt_request *dmreq = async_req->data;
+	struct convert_context *ctx = dmreq->ctx;
+	struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx);
+	struct crypt_config *cc = io->cc;
+
+	if (error == -EINPROGRESS) {
+		complete(&ctx->restart);
+		return;
+	}
+
+	if (!error && cc->iv_gen_ops && cc->iv_gen_ops->post)
+		error = cc->iv_gen_ops->post(cc, iv_of_dmreq(cc, dmreq), dmreq);
+
+	if (error < 0)
+		io->error = -EIO;
+
+	crypt_free_req(cc, req_of_dmreq(cc, dmreq), io->base_bio);
+
+	if (!atomic_dec_and_test(&ctx->cc_pending))
+		return;
+
+	if (bio_data_dir(io->base_bio) == READ)
+		kcryptd_crypt_read_done(io);
+	else
+		kcryptd_crypt_write_io_submit(io, 1);
+}
+
+static void kcryptd_crypt(struct work_struct *work)
+{
+	struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
+
+	if (bio_data_dir(io->base_bio) == READ)
+		kcryptd_crypt_read_convert(io);
+	else
+		kcryptd_crypt_write_convert(io);
+}
+
+static void kcryptd_queue_crypt(struct dm_crypt_io *io)
+{
+	struct crypt_config *cc = io->cc;
+
+	INIT_WORK(&io->work, kcryptd_crypt);
+	queue_work(cc->crypt_queue, &io->work);
+}
+
+/*
+ * Decode key from its hex representation
+ */
+static int crypt_decode_key(u8 *key, char *hex, unsigned int size)
+{
+	char buffer[3];
+	unsigned int i;
+
+	buffer[2] = '\0';
+
+	for (i = 0; i < size; i++) {
+		buffer[0] = *hex++;
+		buffer[1] = *hex++;
+
+		if (kstrtou8(buffer, 16, &key[i]))
+			return -EINVAL;
+	}
+
+	if (*hex != '\0')
+		return -EINVAL;
+
+	return 0;
+}
+
+static void crypt_free_tfms(struct crypt_config *cc)
+{
+	unsigned i;
+
+	if (!cc->tfms)
+		return;
+
+	for (i = 0; i < cc->tfms_count; i++)
+		if (cc->tfms[i] && !IS_ERR(cc->tfms[i])) {
+			crypto_free_ablkcipher(cc->tfms[i]);
+			cc->tfms[i] = NULL;
+		}
+
+	kfree(cc->tfms);
+	cc->tfms = NULL;
+}
+
+static int crypt_alloc_tfms(struct crypt_config *cc, char *ciphermode)
+{
+	unsigned i;
+	int err;
+
+	cc->tfms = kmalloc(cc->tfms_count * sizeof(struct crypto_ablkcipher *),
+			   GFP_KERNEL);
+	if (!cc->tfms)
+		return -ENOMEM;
+
+	for (i = 0; i < cc->tfms_count; i++) {
+		cc->tfms[i] = crypto_alloc_ablkcipher(ciphermode, 0, 0);
+		if (IS_ERR(cc->tfms[i])) {
+			err = PTR_ERR(cc->tfms[i]);
+			crypt_free_tfms(cc);
+			return err;
+		}
+	}
+
+	return 0;
+}
+
+static int crypt_setkey_allcpus(struct crypt_config *cc)
+{
+	unsigned subkey_size;
+	int err = 0, i, r;
+
+	/* Ignore extra keys (which are used for IV etc) */
+	subkey_size = (cc->key_size - cc->key_extra_size) >> ilog2(cc->tfms_count);
+
+	for (i = 0; i < cc->tfms_count; i++) {
+		r = crypto_ablkcipher_setkey(cc->tfms[i],
+					     cc->key + (i * subkey_size),
+					     subkey_size);
+		if (r)
+			err = r;
+	}
+
+	return err;
+}
+
+static int crypt_set_key(struct crypt_config *cc, char *key)
+{
+	int r = -EINVAL;
+	int key_string_len = strlen(key);
+
+	/* The key size may not be changed. */
+	if (cc->key_size != (key_string_len >> 1))
+		goto out;
+
+	/* Hyphen (which gives a key_size of zero) means there is no key. */
+	if (!cc->key_size && strcmp(key, "-"))
+		goto out;
+
+	if (cc->key_size && crypt_decode_key(cc->key, key, cc->key_size) < 0)
+		goto out;
+
+	set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
+
+	r = crypt_setkey_allcpus(cc);
+
+out:
+	/* Hex key string not needed after here, so wipe it. */
+	memset(key, '0', key_string_len);
+
+	return r;
+}
+
+static int crypt_wipe_key(struct crypt_config *cc)
+{
+	clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
+	memset(&cc->key, 0, cc->key_size * sizeof(u8));
+
+	return crypt_setkey_allcpus(cc);
+}
+
+static void crypt_dtr(struct dm_target *ti)
+{
+	struct crypt_config *cc = ti->private;
+
+	ti->private = NULL;
+
+	if (!cc)
+		return;
+
+	if (cc->write_thread)
+		kthread_stop(cc->write_thread);
+
+	if (cc->io_queue)
+		destroy_workqueue(cc->io_queue);
+	if (cc->crypt_queue)
+		destroy_workqueue(cc->crypt_queue);
+
+	crypt_free_tfms(cc);
+
+	if (cc->bs)
+		bioset_free(cc->bs);
+
+	if (cc->page_pool)
+		mempool_destroy(cc->page_pool);
+	if (cc->req_pool)
+		mempool_destroy(cc->req_pool);
+
+	if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
+		cc->iv_gen_ops->dtr(cc);
+
+	if (cc->dev)
+		dm_put_device(ti, cc->dev);
+
+	kzfree(cc->cipher);
+	kzfree(cc->cipher_string);
+
+	/* Must zero key material before freeing */
+	kzfree(cc);
+}
+
+static int crypt_ctr_cipher(struct dm_target *ti,
+			    char *cipher_in, char *key)
+{
+	struct crypt_config *cc = ti->private;
+	char *tmp, *cipher, *chainmode, *ivmode, *ivopts, *keycount;
+	char *cipher_api = NULL;
+	int ret = -EINVAL;
+	char dummy;
+
+	/* Convert to crypto api definition? */
+	if (strchr(cipher_in, '(')) {
+		ti->error = "Bad cipher specification";
+		return -EINVAL;
+	}
+
+	cc->cipher_string = kstrdup(cipher_in, GFP_KERNEL);
+	if (!cc->cipher_string)
+		goto bad_mem;
+
+	/*
+	 * Legacy dm-crypt cipher specification
+	 * cipher[:keycount]-mode-iv:ivopts
+	 */
+	tmp = cipher_in;
+	keycount = strsep(&tmp, "-");
+	cipher = strsep(&keycount, ":");
+
+	if (!keycount)
+		cc->tfms_count = 1;
+	else if (sscanf(keycount, "%u%c", &cc->tfms_count, &dummy) != 1 ||
+		 !is_power_of_2(cc->tfms_count)) {
+		ti->error = "Bad cipher key count specification";
+		return -EINVAL;
+	}
+	cc->key_parts = cc->tfms_count;
+	cc->key_extra_size = 0;
+
+	cc->cipher = kstrdup(cipher, GFP_KERNEL);
+	if (!cc->cipher)
+		goto bad_mem;
+
+	chainmode = strsep(&tmp, "-");
+	ivopts = strsep(&tmp, "-");
+	ivmode = strsep(&ivopts, ":");
+
+	if (tmp)
+		DMWARN("Ignoring unexpected additional cipher options");
+
+	/*
+	 * For compatibility with the original dm-crypt mapping format, if
+	 * only the cipher name is supplied, use cbc-plain.
+	 */
+	if (!chainmode || (!strcmp(chainmode, "plain") && !ivmode)) {
+		chainmode = "cbc";
+		ivmode = "plain";
+	}
+
+	if (strcmp(chainmode, "ecb") && !ivmode) {
+		ti->error = "IV mechanism required";
+		return -EINVAL;
+	}
+
+	cipher_api = kmalloc(CRYPTO_MAX_ALG_NAME, GFP_KERNEL);
+	if (!cipher_api)
+		goto bad_mem;
+
+	ret = snprintf(cipher_api, CRYPTO_MAX_ALG_NAME,
+		       "%s(%s)", chainmode, cipher);
+	if (ret < 0) {
+		kfree(cipher_api);
+		goto bad_mem;
+	}
+
+	/* Allocate cipher */
+	ret = crypt_alloc_tfms(cc, cipher_api);
+	if (ret < 0) {
+		ti->error = "Error allocating crypto tfm";
+		goto bad;
+	}
+
+	/* Initialize IV */
+	cc->iv_size = crypto_ablkcipher_ivsize(any_tfm(cc));
+	if (cc->iv_size)
+		/* at least a 64 bit sector number should fit in our buffer */
+		cc->iv_size = max(cc->iv_size,
+				  (unsigned int)(sizeof(u64) / sizeof(u8)));
+	else if (ivmode) {
+		DMWARN("Selected cipher does not support IVs");
+		ivmode = NULL;
+	}
+
+	/* Choose ivmode, see comments at iv code. */
+	if (ivmode == NULL)
+		cc->iv_gen_ops = NULL;
+	else if (strcmp(ivmode, "plain") == 0)
+		cc->iv_gen_ops = &crypt_iv_plain_ops;
+	else if (strcmp(ivmode, "plain64") == 0)
+		cc->iv_gen_ops = &crypt_iv_plain64_ops;
+	else if (strcmp(ivmode, "essiv") == 0)
+		cc->iv_gen_ops = &crypt_iv_essiv_ops;
+	else if (strcmp(ivmode, "benbi") == 0)
+		cc->iv_gen_ops = &crypt_iv_benbi_ops;
+	else if (strcmp(ivmode, "null") == 0)
+		cc->iv_gen_ops = &crypt_iv_null_ops;
+	else if (strcmp(ivmode, "lmk") == 0) {
+		cc->iv_gen_ops = &crypt_iv_lmk_ops;
+		/*
+		 * Version 2 and 3 is recognised according
+		 * to length of provided multi-key string.
+		 * If present (version 3), last key is used as IV seed.
+		 * All keys (including IV seed) are always the same size.
+		 */
+		if (cc->key_size % cc->key_parts) {
+			cc->key_parts++;
+			cc->key_extra_size = cc->key_size / cc->key_parts;
+		}
+	} else if (strcmp(ivmode, "tcw") == 0) {
+		cc->iv_gen_ops = &crypt_iv_tcw_ops;
+		cc->key_parts += 2; /* IV + whitening */
+		cc->key_extra_size = cc->iv_size + TCW_WHITENING_SIZE;
+	} else {
+		ret = -EINVAL;
+		ti->error = "Invalid IV mode";
+		goto bad;
+	}
+
+	/* Initialize and set key */
+	ret = crypt_set_key(cc, key);
+	if (ret < 0) {
+		ti->error = "Error decoding and setting key";
+		goto bad;
+	}
+
+	/* Allocate IV */
+	if (cc->iv_gen_ops && cc->iv_gen_ops->ctr) {
+		ret = cc->iv_gen_ops->ctr(cc, ti, ivopts);
+		if (ret < 0) {
+			ti->error = "Error creating IV";
+			goto bad;
+		}
+	}
+
+	/* Initialize IV (set keys for ESSIV etc) */
+	if (cc->iv_gen_ops && cc->iv_gen_ops->init) {
+		ret = cc->iv_gen_ops->init(cc);
+		if (ret < 0) {
+			ti->error = "Error initialising IV";
+			goto bad;
+		}
+	}
+
+	ret = 0;
+bad:
+	kfree(cipher_api);
+	return ret;
+
+bad_mem:
+	ti->error = "Cannot allocate cipher strings";
+	return -ENOMEM;
+}
+
+/*
+ * Construct an encryption mapping:
+ * <cipher> <key> <iv_offset> <dev_path> <start>
+ */
+static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
+{
+	struct crypt_config *cc;
+	unsigned int key_size, opt_params;
+	unsigned long long tmpll;
+	int ret;
+	size_t iv_size_padding;
+	struct dm_arg_set as;
+	const char *opt_string;
+	char dummy;
+
+	static struct dm_arg _args[] = {
+		{0, 3, "Invalid number of feature args"},
+	};
+
+	if (argc < 5) {
+		ti->error = "Not enough arguments";
+		return -EINVAL;
+	}
+
+	key_size = strlen(argv[1]) >> 1;
+
+	cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
+	if (!cc) {
+		ti->error = "Cannot allocate encryption context";
+		return -ENOMEM;
+	}
+	cc->key_size = key_size;
+
+	ti->private = cc;
+	ret = crypt_ctr_cipher(ti, argv[0], argv[1]);
+	if (ret < 0)
+		goto bad;
+
+	cc->dmreq_start = sizeof(struct ablkcipher_request);
+	cc->dmreq_start += crypto_ablkcipher_reqsize(any_tfm(cc));
+	cc->dmreq_start = ALIGN(cc->dmreq_start, __alignof__(struct dm_crypt_request));
+
+	if (crypto_ablkcipher_alignmask(any_tfm(cc)) < CRYPTO_MINALIGN) {
+		/* Allocate the padding exactly */
+		iv_size_padding = -(cc->dmreq_start + sizeof(struct dm_crypt_request))
+				& crypto_ablkcipher_alignmask(any_tfm(cc));
+	} else {
+		/*
+		 * If the cipher requires greater alignment than kmalloc
+		 * alignment, we don't know the exact position of the
+		 * initialization vector. We must assume worst case.
+		 */
+		iv_size_padding = crypto_ablkcipher_alignmask(any_tfm(cc));
+	}
+
+	ret = -ENOMEM;
+	cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start +
+			sizeof(struct dm_crypt_request) + iv_size_padding + cc->iv_size);
+	if (!cc->req_pool) {
+		ti->error = "Cannot allocate crypt request mempool";
+		goto bad;
+	}
+
+	cc->per_bio_data_size = ti->per_bio_data_size =
+		ALIGN(sizeof(struct dm_crypt_io) + cc->dmreq_start +
+		      sizeof(struct dm_crypt_request) + iv_size_padding + cc->iv_size,
+		      ARCH_KMALLOC_MINALIGN);
+
+	cc->page_pool = mempool_create_page_pool(BIO_MAX_PAGES, 0);
+	if (!cc->page_pool) {
+		ti->error = "Cannot allocate page mempool";
+		goto bad;
+	}
+
+	cc->bs = bioset_create(MIN_IOS, 0);
+	if (!cc->bs) {
+		ti->error = "Cannot allocate crypt bioset";
+		goto bad;
+	}
+
+	mutex_init(&cc->bio_alloc_lock);
+
+	ret = -EINVAL;
+	if (sscanf(argv[2], "%llu%c", &tmpll, &dummy) != 1) {
+		ti->error = "Invalid iv_offset sector";
+		goto bad;
+	}
+	cc->iv_offset = tmpll;
+
+	if (dm_get_device(ti, argv[3], dm_table_get_mode(ti->table), &cc->dev)) {
+		ti->error = "Device lookup failed";
+		goto bad;
+	}
+
+	if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1) {
+		ti->error = "Invalid device sector";
+		goto bad;
+	}
+	cc->start = tmpll;
+
+	argv += 5;
+	argc -= 5;
+
+	/* Optional parameters */
+	if (argc) {
+		as.argc = argc;
+		as.argv = argv;
+
+		ret = dm_read_arg_group(_args, &as, &opt_params, &ti->error);
+		if (ret)
+			goto bad;
+
+		ret = -EINVAL;
+		while (opt_params--) {
+			opt_string = dm_shift_arg(&as);
+			if (!opt_string) {
+				ti->error = "Not enough feature arguments";
+				goto bad;
+			}
+
+			if (!strcasecmp(opt_string, "allow_discards"))
+				ti->num_discard_bios = 1;
+
+			else if (!strcasecmp(opt_string, "same_cpu_crypt"))
+				set_bit(DM_CRYPT_SAME_CPU, &cc->flags);
+
+			else if (!strcasecmp(opt_string, "submit_from_crypt_cpus"))
+				set_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags);
+
+			else {
+				ti->error = "Invalid feature arguments";
+				goto bad;
+			}
+		}
+	}
+
+	ret = -ENOMEM;
+	cc->io_queue = alloc_workqueue("kcryptd_io", WQ_MEM_RECLAIM, 1);
+	if (!cc->io_queue) {
+		ti->error = "Couldn't create kcryptd io queue";
+		goto bad;
+	}
+
+	if (test_bit(DM_CRYPT_SAME_CPU, &cc->flags))
+		cc->crypt_queue = alloc_workqueue("kcryptd", WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM, 1);
+	else
+		cc->crypt_queue = alloc_workqueue("kcryptd", WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM | WQ_UNBOUND,
+						  num_online_cpus());
+	if (!cc->crypt_queue) {
+		ti->error = "Couldn't create kcryptd queue";
+		goto bad;
+	}
+
+	init_waitqueue_head(&cc->write_thread_wait);
+	cc->write_tree = RB_ROOT;
+
+	cc->write_thread = kthread_create(dmcrypt_write, cc, "dmcrypt_write");
+	if (IS_ERR(cc->write_thread)) {
+		ret = PTR_ERR(cc->write_thread);
+		cc->write_thread = NULL;
+		ti->error = "Couldn't spawn write thread";
+		goto bad;
+	}
+	wake_up_process(cc->write_thread);
+
+	ti->num_flush_bios = 1;
+	ti->discard_zeroes_data_unsupported = true;
+
+	return 0;
+
+bad:
+	crypt_dtr(ti);
+	return ret;
+}
+
+static int crypt_map(struct dm_target *ti, struct bio *bio)
+{
+	struct dm_crypt_io *io;
+	struct crypt_config *cc = ti->private;
+
+	/*
+	 * If bio is REQ_FLUSH or REQ_DISCARD, just bypass crypt queues.
+	 * - for REQ_FLUSH device-mapper core ensures that no IO is in-flight
+	 * - for REQ_DISCARD caller must use flush if IO ordering matters
+	 */
+	if (unlikely(bio->bi_rw & (REQ_FLUSH | REQ_DISCARD))) {
+		bio->bi_bdev = cc->dev->bdev;
+		if (bio_sectors(bio))
+			bio->bi_iter.bi_sector = cc->start +
+				dm_target_offset(ti, bio->bi_iter.bi_sector);
+		return DM_MAPIO_REMAPPED;
+	}
+
+	io = dm_per_bio_data(bio, cc->per_bio_data_size);
+	crypt_io_init(io, cc, bio, dm_target_offset(ti, bio->bi_iter.bi_sector));
+	io->ctx.req = (struct ablkcipher_request *)(io + 1);
+
+	if (bio_data_dir(io->base_bio) == READ) {
+		if (kcryptd_io_read(io, GFP_NOWAIT))
+			kcryptd_queue_read(io);
+	} else
+		kcryptd_queue_crypt(io);
+
+	return DM_MAPIO_SUBMITTED;
+}
+
+static void crypt_status(struct dm_target *ti, status_type_t type,
+			 unsigned status_flags, char *result, unsigned maxlen)
+{
+	struct crypt_config *cc = ti->private;
+	unsigned i, sz = 0;
+	int num_feature_args = 0;
+
+	switch (type) {
+	case STATUSTYPE_INFO:
+		result[0] = '\0';
+		break;
+
+	case STATUSTYPE_TABLE:
+		DMEMIT("%s ", cc->cipher_string);
+
+		if (cc->key_size > 0)
+			for (i = 0; i < cc->key_size; i++)
+				DMEMIT("%02x", cc->key[i]);
+		else
+			DMEMIT("-");
+
+		DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset,
+				cc->dev->name, (unsigned long long)cc->start);
+
+		num_feature_args += !!ti->num_discard_bios;
+		num_feature_args += test_bit(DM_CRYPT_SAME_CPU, &cc->flags);
+		num_feature_args += test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags);
+		if (num_feature_args) {
+			DMEMIT(" %d", num_feature_args);
+			if (ti->num_discard_bios)
+				DMEMIT(" allow_discards");
+			if (test_bit(DM_CRYPT_SAME_CPU, &cc->flags))
+				DMEMIT(" same_cpu_crypt");
+			if (test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags))
+				DMEMIT(" submit_from_crypt_cpus");
+		}
+
+		break;
+	}
+}
+
+static void crypt_postsuspend(struct dm_target *ti)
+{
+	struct crypt_config *cc = ti->private;
+
+	set_bit(DM_CRYPT_SUSPENDED, &cc->flags);
+}
+
+static int crypt_preresume(struct dm_target *ti)
+{
+	struct crypt_config *cc = ti->private;
+
+	if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) {
+		DMERR("aborting resume - crypt key is not set.");
+		return -EAGAIN;
+	}
+
+	return 0;
+}
+
+static void crypt_resume(struct dm_target *ti)
+{
+	struct crypt_config *cc = ti->private;
+
+	clear_bit(DM_CRYPT_SUSPENDED, &cc->flags);
+}
+
+/* Message interface
+ *	key set <key>
+ *	key wipe
+ */
+static int crypt_message(struct dm_target *ti, unsigned argc, char **argv)
+{
+	struct crypt_config *cc = ti->private;
+	int ret = -EINVAL;
+
+	if (argc < 2)
+		goto error;
+
+	if (!strcasecmp(argv[0], "key")) {
+		if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) {
+			DMWARN("not suspended during key manipulation.");
+			return -EINVAL;
+		}
+		if (argc == 3 && !strcasecmp(argv[1], "set")) {
+			ret = crypt_set_key(cc, argv[2]);
+			if (ret)
+				return ret;
+			if (cc->iv_gen_ops && cc->iv_gen_ops->init)
+				ret = cc->iv_gen_ops->init(cc);
+			return ret;
+		}
+		if (argc == 2 && !strcasecmp(argv[1], "wipe")) {
+			if (cc->iv_gen_ops && cc->iv_gen_ops->wipe) {
+				ret = cc->iv_gen_ops->wipe(cc);
+				if (ret)
+					return ret;
+			}
+			return crypt_wipe_key(cc);
+		}
+	}
+
+error:
+	DMWARN("unrecognised message received.");
+	return -EINVAL;
+}
+
+static int crypt_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
+		       struct bio_vec *biovec, int max_size)
+{
+	struct crypt_config *cc = ti->private;
+	struct request_queue *q = bdev_get_queue(cc->dev->bdev);
+
+	if (!q->merge_bvec_fn)
+		return max_size;
+
+	bvm->bi_bdev = cc->dev->bdev;
+	bvm->bi_sector = cc->start + dm_target_offset(ti, bvm->bi_sector);
+
+	return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
+}
+
+static int crypt_iterate_devices(struct dm_target *ti,
+				 iterate_devices_callout_fn fn, void *data)
+{
+	struct crypt_config *cc = ti->private;
+
+	return fn(ti, cc->dev, cc->start, ti->len, data);
+}
+
+static struct target_type crypt_target = {
+	.name   = "crypt",
+	.version = {1, 14, 0},
+	.module = THIS_MODULE,
+	.ctr    = crypt_ctr,
+	.dtr    = crypt_dtr,
+	.map    = crypt_map,
+	.status = crypt_status,
+	.postsuspend = crypt_postsuspend,
+	.preresume = crypt_preresume,
+	.resume = crypt_resume,
+	.message = crypt_message,
+	.merge  = crypt_merge,
+	.iterate_devices = crypt_iterate_devices,
+};
+
+static int __init dm_crypt_init(void)
+{
+	int r;
+
+	r = dm_register_target(&crypt_target);
+	if (r < 0)
+		DMERR("register failed %d", r);
+
+	return r;
+}
+
+static void __exit dm_crypt_exit(void)
+{
+	dm_unregister_target(&crypt_target);
+}
+
+module_init(dm_crypt_init);
+module_exit(dm_crypt_exit);
+
+MODULE_AUTHOR("Jana Saout <jana@saout.de>");
+MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption");
+MODULE_LICENSE("GPL");