text: /*
   * Copyright (C) 2003 Jana Saout <jana@saout.de>
   * Copyright (C) 2004 Clemens Fruhwirth <clemens@endorphin.org>
   * Copyright (C) 2006-2017 Red Hat, Inc. All rights reserved.
   * Copyright (C) 2013-2017 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/key.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 <linux/ctype.h>
  #include <asm/page.h>
  #include <asm/unaligned.h>
  #include <crypto/hash.h>
  #include <crypto/md5.h>
  #include <crypto/algapi.h>
  #include <crypto/skcipher.h>
  #include <crypto/aead.h>
  #include <crypto/authenc.h>
  #include <linux/rtnetlink.h> /* for struct rtattr and RTA macros only */
  #include <keys/user-type.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;
  	union {
  		struct skcipher_request *req;
  		struct aead_request *req_aead;
  	} r;
  
  };
  
  /*
   * per bio private data
   */
  struct dm_crypt_io {
  	struct crypt_config *cc;
  	struct bio *base_bio;
  	u8 *integrity_metadata;
  	bool integrity_metadata_from_pool;
  	struct work_struct work;
  
  	struct convert_context ctx;
  
  	atomic_t io_pending;
  	blk_status_t error;
  	sector_t sector;
  
  	struct rb_node rb_node;
  } CRYPTO_MINALIGN_ATTR;
  
  struct dm_crypt_request {
  	struct convert_context *ctx;
  	struct scatterlist sg_in[4];
  	struct scatterlist sg_out[4];
  	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_ahash *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 };
  
  enum cipher_flags {
  	CRYPT_MODE_INTEGRITY_AEAD,	/* Use authenticated mode for cihper */
  	CRYPT_IV_LARGE_SECTORS,		/* Calculate IV from sector_size, not 512B sectors */
  };
  
  /*
   * 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,
  	 * encryption requeusts/buffer pages and integrity tags
  	 */
  	mempool_t *req_pool;
  	mempool_t *page_pool;
  	mempool_t *tag_pool;
  	unsigned tag_pool_max_sectors;
  
  	struct percpu_counter n_allocated_pages;
  
  	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;
  	char *cipher_auth;
  	char *key_string;
  
  	const 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;
  	unsigned short int sector_size;
  	unsigned char sector_shift;
  
  	/* ESSIV: struct crypto_cipher *essiv_tfm */
  	void *iv_private;
  	union {
  		struct crypto_skcipher **tfms;
  		struct crypto_aead **tfms_aead;
  	} cipher_tfm;
  	unsigned tfms_count;
  	unsigned long cipher_flags;
  
  	/*
  	 * Layout of each crypto request:
  	 *
  	 *   struct skcipher_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 */
  	unsigned int key_mac_size;   /* MAC key size for authenc(...) */
  
  	unsigned int integrity_tag_size;
  	unsigned int integrity_iv_size;
  	unsigned int on_disk_tag_size;
  
  	u8 *authenc_key; /* space for keys in authenc() format (if used) */
  	u8 key[0];
  };
  
  #define MIN_IOS		64
  #define MAX_TAG_SIZE	480
  #define POOL_ENTRY_SIZE	512
  
  static DEFINE_SPINLOCK(dm_crypt_clients_lock);
  static unsigned dm_crypt_clients_n = 0;
  static volatile unsigned long dm_crypt_pages_per_client;
  #define DM_CRYPT_MEMORY_PERCENT			2
  #define DM_CRYPT_MIN_PAGES_PER_CLIENT		(BIO_MAX_PAGES * 16)
  
  static void clone_init(struct dm_crypt_io *, struct bio *);
  static void kcryptd_queue_crypt(struct dm_crypt_io *io);
  static struct scatterlist *crypt_get_sg_data(struct crypt_config *cc,
  					     struct scatterlist *sg);
  
  /*
   * Use this to access cipher attributes that are independent of the key.
   */
  static struct crypto_skcipher *any_tfm(struct crypt_config *cc)
  {
  	return cc->cipher_tfm.tfms[0];
  }
  
  static struct crypto_aead *any_tfm_aead(struct crypt_config *cc)
  {
  	return cc->cipher_tfm.tfms_aead[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.
   *
   * plain64be: the initial vector is the 64-bit big-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;
  }
  
  static int crypt_iv_plain64be_gen(struct crypt_config *cc, u8 *iv,
  				  struct dm_crypt_request *dmreq)
  {
  	memset(iv, 0, cc->iv_size);
  	/* iv_size is at least of size u64; usually it is 16 bytes */
  	*(__be64 *)&iv[cc->iv_size - sizeof(u64)] = cpu_to_be64(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;
  	AHASH_REQUEST_ON_STACK(req, essiv->hash_tfm);
  	struct scatterlist sg;
  	struct crypto_cipher *essiv_tfm;
  	int err;
  
  	sg_init_one(&sg, cc->key, cc->key_size);
  	ahash_request_set_tfm(req, essiv->hash_tfm);
  	ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
  	ahash_request_set_crypt(req, &sg, essiv->salt, cc->key_size);
  
  	err = crypto_ahash_digest(req);
  	ahash_request_zero(req);
  	if (err)
  		return err;
  
  	essiv_tfm = cc->iv_private;
  
  	err = crypto_cipher_setkey(essiv_tfm, essiv->salt,
  			    crypto_ahash_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_ahash_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;
  }
  
  /* Allocate the cipher for ESSIV */
  static struct crypto_cipher *alloc_essiv_cipher(struct crypt_config *cc,
  						struct dm_target *ti,
  						const u8 *salt,
  						unsigned int 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) != cc->iv_size) {
  		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_ahash(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_ahash *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_ahash(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_ahash_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 = alloc_essiv_cipher(cc, ti, salt,
  				       crypto_ahash_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_ahash(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_skcipher_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;
  
  	if (cc->sector_size != (1 << SECTOR_SHIFT)) {
  		ti->error = "Unsupported sector size for LMK";
  		return -EINVAL;
  	}
  
  	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)
  {
  	struct scatterlist *sg;
  	u8 *src;
  	int r = 0;
  
  	if (bio_data_dir(dmreq->ctx->bio_in) == WRITE) {
  		sg = crypt_get_sg_data(cc, dmreq->sg_in);
  		src = kmap_atomic(sg_page(sg));
  		r = crypt_iv_lmk_one(cc, iv, dmreq, src + sg->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)
  {
  	struct scatterlist *sg;
  	u8 *dst;
  	int r;
  
  	if (bio_data_dir(dmreq->ctx->bio_in) == WRITE)
  		return 0;
  
  	sg = crypt_get_sg_data(cc, dmreq->sg_out);
  	dst = kmap_atomic(sg_page(sg));
  	r = crypt_iv_lmk_one(cc, iv, dmreq, dst + sg->offset);
  
  	/* Tweak the first block of plaintext sector */
  	if (!r)
  		crypto_xor(dst + sg->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->sector_size != (1 << SECTOR_SHIFT)) {
  		ti->error = "Unsupported sector size for TCW";
  		return -EINVAL;
  	}
  
  	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;
  	__le64 sector = cpu_to_le64(dmreq->iv_sector);
  	u8 buf[TCW_WHITENING_SIZE];
  	SHASH_DESC_ON_STACK(desc, tcw->crc32_tfm);
  	int i, r;
  
  	/* xor whitening with sector number */
  	crypto_xor_cpy(buf, tcw->whitening, (u8 *)&sector, 8);
  	crypto_xor_cpy(&buf[8], tcw->whitening + 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 scatterlist *sg;
  	struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
  	__le64 sector = cpu_to_le64(dmreq->iv_sector);
  	u8 *src;
  	int r = 0;
  
  	/* Remove whitening from ciphertext */
  	if (bio_data_dir(dmreq->ctx->bio_in) != WRITE) {
  		sg = crypt_get_sg_data(cc, dmreq->sg_in);
  		src = kmap_atomic(sg_page(sg));
  		r = crypt_iv_tcw_whitening(cc, dmreq, src + sg->offset);
  		kunmap_atomic(src);
  	}
  
  	/* Calculate IV */
  	crypto_xor_cpy(iv, tcw->iv_seed, (u8 *)&sector, 8);
  	if (cc->iv_size > 8)
  		crypto_xor_cpy(&iv[8], tcw->iv_seed + 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)
  {
  	struct scatterlist *sg;
  	u8 *dst;
  	int r;
  
  	if (bio_data_dir(dmreq->ctx->bio_in) != WRITE)
  		return 0;
  
  	/* Apply whitening on ciphertext */
  	sg = crypt_get_sg_data(cc, dmreq->sg_out);
  	dst = kmap_atomic(sg_page(sg));
  	r = crypt_iv_tcw_whitening(cc, dmreq, dst + sg->offset);
  	kunmap_atomic(dst);
  
  	return r;
  }
  
  static int crypt_iv_random_gen(struct crypt_config *cc, u8 *iv,
  				struct dm_crypt_request *dmreq)
  {
  	/* Used only for writes, there must be an additional space to store IV */
  	get_random_bytes(iv, cc->iv_size);
  	return 0;
  }
  
  static const struct crypt_iv_operations crypt_iv_plain_ops = {
  	.generator = crypt_iv_plain_gen
  };
  
  static const struct crypt_iv_operations crypt_iv_plain64_ops = {
  	.generator = crypt_iv_plain64_gen
  };
  
  static const struct crypt_iv_operations crypt_iv_plain64be_ops = {
  	.generator = crypt_iv_plain64be_gen
  };
  
  static const 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 const struct crypt_iv_operations crypt_iv_benbi_ops = {
  	.ctr	   = crypt_iv_benbi_ctr,
  	.dtr	   = crypt_iv_benbi_dtr,
  	.generator = crypt_iv_benbi_gen
  };
  
  static const struct crypt_iv_operations crypt_iv_null_ops = {
  	.generator = crypt_iv_null_gen
  };
  
  static const 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 const 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 struct crypt_iv_operations crypt_iv_random_ops = {
  	.generator = crypt_iv_random_gen
  };
  
  /*
   * Integrity extensions
   */
  static bool crypt_integrity_aead(struct crypt_config *cc)
  {
  	return test_bit(CRYPT_MODE_INTEGRITY_AEAD, &cc->cipher_flags);
  }
  
  static bool crypt_integrity_hmac(struct crypt_config *cc)
  {
  	return crypt_integrity_aead(cc) && cc->key_mac_size;
  }
  
  /* Get sg containing data */
  static struct scatterlist *crypt_get_sg_data(struct crypt_config *cc,
  					     struct scatterlist *sg)
  {
  	if (unlikely(crypt_integrity_aead(cc)))
  		return &sg[2];
  
  	return sg;
  }
  
  static int dm_crypt_integrity_io_alloc(struct dm_crypt_io *io, struct bio *bio)
  {
  	struct bio_integrity_payload *bip;
  	unsigned int tag_len;
  	int ret;
  
  	if (!bio_sectors(bio) || !io->cc->on_disk_tag_size)
  		return 0;
  
  	bip = bio_integrity_alloc(bio, GFP_NOIO, 1);
  	if (IS_ERR(bip))
  		return PTR_ERR(bip);
  
  	tag_len = io->cc->on_disk_tag_size * bio_sectors(bio);
  
  	bip->bip_iter.bi_size = tag_len;
  	bip->bip_iter.bi_sector = io->cc->start + io->sector;
  
  	ret = bio_integrity_add_page(bio, virt_to_page(io->integrity_metadata),
  				     tag_len, offset_in_page(io->integrity_metadata));
  	if (unlikely(ret != tag_len))
  		return -ENOMEM;
  
  	return 0;
  }
  
  static int crypt_integrity_ctr(struct crypt_config *cc, struct dm_target *ti)
  {
  #ifdef CONFIG_BLK_DEV_INTEGRITY
  	struct blk_integrity *bi = blk_get_integrity(cc->dev->bdev->bd_disk);
  
  	/* From now we require underlying device with our integrity profile */
  	if (!bi || strcasecmp(bi->profile->name, "DM-DIF-EXT-TAG")) {
  		ti->error = "Integrity profile not supported.";
  		return -EINVAL;
  	}
  
  	if (bi->tag_size != cc->on_disk_tag_size ||
  	    bi->tuple_size != cc->on_disk_tag_size) {
  		ti->error = "Integrity profile tag size mismatch.";
  		return -EINVAL;
  	}
  	if (1 << bi->interval_exp != cc->sector_size) {
  		ti->error = "Integrity profile sector size mismatch.";
  		return -EINVAL;
  	}
  
  	if (crypt_integrity_aead(cc)) {
  		cc->integrity_tag_size = cc->on_disk_tag_size - cc->integrity_iv_size;
  		DMINFO("Integrity AEAD, tag size %u, IV size %u.",
  		       cc->integrity_tag_size, cc->integrity_iv_size);
  
  		if (crypto_aead_setauthsize(any_tfm_aead(cc), cc->integrity_tag_size)) {
  			ti->error = "Integrity AEAD auth tag size is not supported.";
  			return -EINVAL;
  		}
  	} else if (cc->integrity_iv_size)
  		DMINFO("Additional per-sector space %u bytes for IV.",
  		       cc->integrity_iv_size);
  
  	if ((cc->integrity_tag_size + cc->integrity_iv_size) != bi->tag_size) {
  		ti->error = "Not enough space for integrity tag in the profile.";
  		return -EINVAL;
  	}
  
  	return 0;
  #else
  	ti->error = "Integrity profile not supported.";
  	return -EINVAL;
  #endif
  }
  
  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,
  					     void *req)
  {
  	return (struct dm_crypt_request *)((char *)req + cc->dmreq_start);
  }
  
  static void *req_of_dmreq(struct crypt_config *cc, struct dm_crypt_request *dmreq)
  {
  	return (void *)((char *)dmreq - cc->dmreq_start);
  }
  
  static u8 *iv_of_dmreq(struct crypt_config *cc,
  		       struct dm_crypt_request *dmreq)
  {
  	if (crypt_integrity_aead(cc))
  		return (u8 *)ALIGN((unsigned long)(dmreq + 1),
  			crypto_aead_alignmask(any_tfm_aead(cc)) + 1);
  	else
  		return (u8 *)ALIGN((unsigned long)(dmreq + 1),
  			crypto_skcipher_alignmask(any_tfm(cc)) + 1);
  }
  
  static u8 *org_iv_of_dmreq(struct crypt_config *cc,
  		       struct dm_crypt_request *dmreq)
  {
  	return iv_of_dmreq(cc, dmreq) + cc->iv_size;
  }
  
  static uint64_t *org_sector_of_dmreq(struct crypt_config *cc,
  		       struct dm_crypt_request *dmreq)
  {
  	u8 *ptr = iv_of_dmreq(cc, dmreq) + cc->iv_size + cc->iv_size;
  	return (uint64_t*) ptr;
  }
  
  static unsigned int *org_tag_of_dmreq(struct crypt_config *cc,
  		       struct dm_crypt_request *dmreq)
  {
  	u8 *ptr = iv_of_dmreq(cc, dmreq) + cc->iv_size +
  		  cc->iv_size + sizeof(uint64_t);
  	return (unsigned int*)ptr;
  }
  
  static void *tag_from_dmreq(struct crypt_config *cc,
  				struct dm_crypt_request *dmreq)
  {
  	struct convert_context *ctx = dmreq->ctx;
  	struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx);
  
  	return &io->integrity_metadata[*org_tag_of_dmreq(cc, dmreq) *
  		cc->on_disk_tag_size];
  }
  
  static void *iv_tag_from_dmreq(struct crypt_config *cc,
  			       struct dm_crypt_request *dmreq)
  {
  	return tag_from_dmreq(cc, dmreq) + cc->integrity_tag_size;
  }
  
  static int crypt_convert_block_aead(struct crypt_config *cc,
  				     struct convert_context *ctx,
  				     struct aead_request *req,
  				     unsigned int tag_offset)
  {
  	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, *org_iv, *tag_iv, *tag;
  	uint64_t *sector;
  	int r = 0;
  
  	BUG_ON(cc->integrity_iv_size && cc->integrity_iv_size != cc->iv_size);
  
  	/* Reject unexpected unaligned bio. */
  	if (unlikely(bv_in.bv_len & (cc->sector_size - 1)))
  		return -EIO;
  
  	dmreq = dmreq_of_req(cc, req);
  	dmreq->iv_sector = ctx->cc_sector;
  	if (test_bit(CRYPT_IV_LARGE_SECTORS, &cc->cipher_flags))
  		dmreq->iv_sector >>= cc->sector_shift;
  	dmreq->ctx = ctx;
  
  	*org_tag_of_dmreq(cc, dmreq) = tag_offset;
  
  	sector = org_sector_of_dmreq(cc, dmreq);
  	*sector = cpu_to_le64(ctx->cc_sector - cc->iv_offset);
  
  	iv = iv_of_dmreq(cc, dmreq);
  	org_iv = org_iv_of_dmreq(cc, dmreq);
  	tag = tag_from_dmreq(cc, dmreq);
  	tag_iv = iv_tag_from_dmreq(cc, dmreq);
  
  	/* AEAD request:
  	 *  |----- AAD -------|------ DATA -------|-- AUTH TAG --|
  	 *  | (authenticated) | (auth+encryption) |              |
  	 *  | sector_LE |  IV |  sector in/out    |  tag in/out  |
  	 */
  	sg_init_table(dmreq->sg_in, 4);
  	sg_set_buf(&dmreq->sg_in[0], sector, sizeof(uint64_t));
  	sg_set_buf(&dmreq->sg_in[1], org_iv, cc->iv_size);
  	sg_set_page(&dmreq->sg_in[2], bv_in.bv_page, cc->sector_size, bv_in.bv_offset);
  	sg_set_buf(&dmreq->sg_in[3], tag, cc->integrity_tag_size);
  
  	sg_init_table(dmreq->sg_out, 4);
  	sg_set_buf(&dmreq->sg_out[0], sector, sizeof(uint64_t));
  	sg_set_buf(&dmreq->sg_out[1], org_iv, cc->iv_size);
  	sg_set_page(&dmreq->sg_out[2], bv_out.bv_page, cc->sector_size, bv_out.bv_offset);
  	sg_set_buf(&dmreq->sg_out[3], tag, cc->integrity_tag_size);
  
  	if (cc->iv_gen_ops) {
  		/* For READs use IV stored in integrity metadata */
  		if (cc->integrity_iv_size && bio_data_dir(ctx->bio_in) != WRITE) {
  			memcpy(org_iv, tag_iv, cc->iv_size);
  		} else {
  			r = cc->iv_gen_ops->generator(cc, org_iv, dmreq);
  			if (r < 0)
  				return r;
  			/* Store generated IV in integrity metadata */
  			if (cc->integrity_iv_size)
  				memcpy(tag_iv, org_iv, cc->iv_size);
  		}
  		/* Working copy of IV, to be modified in crypto API */
  		memcpy(iv, org_iv, cc->iv_size);
  	}
  
  	aead_request_set_ad(req, sizeof(uint64_t) + cc->iv_size);
  	if (bio_data_dir(ctx->bio_in) == WRITE) {
  		aead_request_set_crypt(req, dmreq->sg_in, dmreq->sg_out,
  				       cc->sector_size, iv);
  		r = crypto_aead_encrypt(req);
  		if (cc->integrity_tag_size + cc->integrity_iv_size != cc->on_disk_tag_size)
  			memset(tag + cc->integrity_tag_size + cc->integrity_iv_size, 0,
  			       cc->on_disk_tag_size - (cc->integrity_tag_size + cc->integrity_iv_size));
  	} else {
  		aead_request_set_crypt(req, dmreq->sg_in, dmreq->sg_out,
  				       cc->sector_size + cc->integrity_tag_size, iv);
  		r = crypto_aead_decrypt(req);
  	}
  
  	if (r == -EBADMSG)
  		DMERR_LIMIT("INTEGRITY AEAD ERROR, sector %llu",
  			    (unsigned long long)le64_to_cpu(*sector));
  
  	if (!r && cc->iv_gen_ops && cc->iv_gen_ops->post)
  		r = cc->iv_gen_ops->post(cc, org_iv, dmreq);
  
  	bio_advance_iter(ctx->bio_in, &ctx->iter_in, cc->sector_size);
  	bio_advance_iter(ctx->bio_out, &ctx->iter_out, cc->sector_size);
  
  	return r;
  }
  
  static int crypt_convert_block_skcipher(struct crypt_config *cc,
  					struct convert_context *ctx,
  					struct skcipher_request *req,
  					unsigned int tag_offset)
  {
  	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 scatterlist *sg_in, *sg_out;
  	struct dm_crypt_request *dmreq;
  	u8 *iv, *org_iv, *tag_iv;
  	uint64_t *sector;
  	int r = 0;
  
  	/* Reject unexpected unaligned bio. */
  	if (unlikely(bv_in.bv_len & (cc->sector_size - 1)))
  		return -EIO;
  
  	dmreq = dmreq_of_req(cc, req);
  	dmreq->iv_sector = ctx->cc_sector;
  	if (test_bit(CRYPT_IV_LARGE_SECTORS, &cc->cipher_flags))
  		dmreq->iv_sector >>= cc->sector_shift;
  	dmreq->ctx = ctx;
  
  	*org_tag_of_dmreq(cc, dmreq) = tag_offset;
  
  	iv = iv_of_dmreq(cc, dmreq);
  	org_iv = org_iv_of_dmreq(cc, dmreq);
  	tag_iv = iv_tag_from_dmreq(cc, dmreq);
  
  	sector = org_sector_of_dmreq(cc, dmreq);
  	*sector = cpu_to_le64(ctx->cc_sector - cc->iv_offset);
  
  	/* For skcipher we use only the first sg item */
  	sg_in  = &dmreq->sg_in[0];
  	sg_out = &dmreq->sg_out[0];
  
  	sg_init_table(sg_in, 1);
  	sg_set_page(sg_in, bv_in.bv_page, cc->sector_size, bv_in.bv_offset);
  
  	sg_init_table(sg_out, 1);
  	sg_set_page(sg_out, bv_out.bv_page, cc->sector_size, bv_out.bv_offset);
  
  	if (cc->iv_gen_ops) {
  		/* For READs use IV stored in integrity metadata */
  		if (cc->integrity_iv_size && bio_data_dir(ctx->bio_in) != WRITE) {
  			memcpy(org_iv, tag_iv, cc->integrity_iv_size);
  		} else {
  			r = cc->iv_gen_ops->generator(cc, org_iv, dmreq);
  			if (r < 0)
  				return r;
  			/* Store generated IV in integrity metadata */
  			if (cc->integrity_iv_size)
  				memcpy(tag_iv, org_iv, cc->integrity_iv_size);
  		}
  		/* Working copy of IV, to be modified in crypto API */
  		memcpy(iv, org_iv, cc->iv_size);
  	}
  
  	skcipher_request_set_crypt(req, sg_in, sg_out, cc->sector_size, iv);
  
  	if (bio_data_dir(ctx->bio_in) == WRITE)
  		r = crypto_skcipher_encrypt(req);
  	else
  		r = crypto_skcipher_decrypt(req);
  
  	if (!r && cc->iv_gen_ops && cc->iv_gen_ops->post)
  		r = cc->iv_gen_ops->post(cc, org_iv, dmreq);
  
  	bio_advance_iter(ctx->bio_in, &ctx->iter_in, cc->sector_size);
  	bio_advance_iter(ctx->bio_out, &ctx->iter_out, cc->sector_size);
  
  	return r;
  }
  
  static void kcryptd_async_done(struct crypto_async_request *async_req,
  			       int error);
  
  static void crypt_alloc_req_skcipher(struct crypt_config *cc,
  				     struct convert_context *ctx)
  {
  	unsigned key_index = ctx->cc_sector & (cc->tfms_count - 1);
  
  	if (!ctx->r.req)
  		ctx->r.req = mempool_alloc(cc->req_pool, GFP_NOIO);
  
  	skcipher_request_set_tfm(ctx->r.req, cc->cipher_tfm.tfms[key_index]);
  
  	/*
  	 * Use REQ_MAY_BACKLOG so a cipher driver internally backlogs
  	 * requests if driver request queue is full.
  	 */
  	skcipher_request_set_callback(ctx->r.req,
  	    CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
  	    kcryptd_async_done, dmreq_of_req(cc, ctx->r.req));
  }
  
  static void crypt_alloc_req_aead(struct crypt_config *cc,
  				 struct convert_context *ctx)
  {
  	if (!ctx->r.req_aead)
  		ctx->r.req_aead = mempool_alloc(cc->req_pool, GFP_NOIO);
  
  	aead_request_set_tfm(ctx->r.req_aead, cc->cipher_tfm.tfms_aead[0]);
  
  	/*
  	 * Use REQ_MAY_BACKLOG so a cipher driver internally backlogs
  	 * requests if driver request queue is full.
  	 */
  	aead_request_set_callback(ctx->r.req_aead,
  	    CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
  	    kcryptd_async_done, dmreq_of_req(cc, ctx->r.req_aead));
  }
  
  static void crypt_alloc_req(struct crypt_config *cc,
  			    struct convert_context *ctx)
  {
  	if (crypt_integrity_aead(cc))
  		crypt_alloc_req_aead(cc, ctx);
  	else
  		crypt_alloc_req_skcipher(cc, ctx);
  }
  
  static void crypt_free_req_skcipher(struct crypt_config *cc,
  				    struct skcipher_request *req, struct bio *base_bio)
  {
  	struct dm_crypt_io *io = dm_per_bio_data(base_bio, cc->per_bio_data_size);
  
  	if ((struct skcipher_request *)(io + 1) != req)
  		mempool_free(req, cc->req_pool);
  }
  
  static void crypt_free_req_aead(struct crypt_config *cc,
  				struct aead_request *req, struct bio *base_bio)
  {
  	struct dm_crypt_io *io = dm_per_bio_data(base_bio, cc->per_bio_data_size);
  
  	if ((struct aead_request *)(io + 1) != req)
  		mempool_free(req, cc->req_pool);
  }
  
  static void crypt_free_req(struct crypt_config *cc, void *req, struct bio *base_bio)
  {
  	if (crypt_integrity_aead(cc))
  		crypt_free_req_aead(cc, req, base_bio);
  	else
  		crypt_free_req_skcipher(cc, req, base_bio);
  }
  
  /*
   * Encrypt / decrypt data from one bio to another one (can be the same one)
   */
  static blk_status_t crypt_convert(struct crypt_config *cc,
  			 struct convert_context *ctx)
  {
  	unsigned int tag_offset = 0;
  	unsigned int sector_step = cc->sector_size >> SECTOR_SHIFT;
  	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);
  
  		if (crypt_integrity_aead(cc))
  			r = crypt_convert_block_aead(cc, ctx, ctx->r.req_aead, tag_offset);
  		else
  			r = crypt_convert_block_skcipher(cc, ctx, ctx->r.req, tag_offset);
  
  		switch (r) {
  		/*
  		 * The request was queued by a crypto driver
  		 * but the driver request queue is full, let's wait.
  		 */
  		case -EBUSY:
  			wait_for_completion(&ctx->restart);
  			reinit_completion(&ctx->restart);
  			/* fall through */
  		/*
  		 * The request is queued and processed asynchronously,
  		 * completion function kcryptd_async_done() will be called.
  		 */
  		case -EINPROGRESS:
  			ctx->r.req = NULL;
  			ctx->cc_sector += sector_step;
  			tag_offset++;
  			continue;
  		/*
  		 * The request was already processed (synchronously).
  		 */
  		case 0:
  			atomic_dec(&ctx->cc_pending);
  			ctx->cc_sector += sector_step;
  			tag_offset++;
  			cond_resched();
  			continue;
  		/*
  		 * There was a data integrity error.
  		 */
  		case -EBADMSG:
  			atomic_dec(&ctx->cc_pending);
  			return BLK_STS_PROTECTION;
  		/*
  		 * There was an error while processing the request.
  		 */
  		default:
  			atomic_dec(&ctx->cc_pending);
  			return BLK_STS_IOERR;
  		}
  	}
  
  	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 (but only because
   * max_segment_size is being constrained to PAGE_SIZE).
   *
   * 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;
  
  retry:
  	if (unlikely(gfp_mask & __GFP_DIRECT_RECLAIM))
  		mutex_lock(&cc->bio_alloc_lock);
  
  	clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs);
  	if (!clone)
  		goto out;
  
  	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_DIRECT_RECLAIM;
  			goto retry;
  		}
  
  		len = (remaining_size > PAGE_SIZE) ? PAGE_SIZE : remaining_size;
  
  		bio_add_page(clone, page, len, 0);
  
  		remaining_size -= len;
  	}
  
  	/* Allocate space for integrity tags */
  	if (dm_crypt_integrity_io_alloc(io, clone)) {
  		crypt_free_buffer_pages(cc, clone);
  		bio_put(clone);
  		clone = NULL;
  	}
  out:
  	if (unlikely(gfp_mask & __GFP_DIRECT_RECLAIM))
  		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);
  	}
  }
  
  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.r.req = NULL;
  	io->integrity_metadata = NULL;
  	io->integrity_metadata_from_pool = false;
  	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;
  	blk_status_t error = io->error;
  
  	if (!atomic_dec_and_test(&io->io_pending))
  		return;
  
  	if (io->ctx.r.req)
  		crypt_free_req(cc, io->ctx.r.req, base_bio);
  
  	if (unlikely(io->integrity_metadata_from_pool))
  		mempool_free(io->integrity_metadata, io->cc->tag_pool);
  	else
  		kfree(io->integrity_metadata);
  
  	base_bio->bi_status = error;
  	bio_endio(base_bio);
  }
  
  /*
   * 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)
  {
  	struct dm_crypt_io *io = clone->bi_private;
  	struct crypt_config *cc = io->cc;
  	unsigned rw = bio_data_dir(clone);
  	blk_status_t error;
  
  	/*
  	 * free the processed pages
  	 */
  	if (rw == WRITE)
  		crypt_free_buffer_pages(cc, clone);
  
  	error = clone->bi_status;
  	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;
  	bio_set_dev(clone, cc->dev->bdev);
  	clone->bi_opf	  = io->base_bio->bi_opf;
  }
  
  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;
  
  	if (dm_crypt_integrity_io_alloc(io, clone)) {
  		crypt_dec_pending(io);
  		bio_put(clone);
  		return 1;
  	}
  
  	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 = BLK_STS_RESOURCE;
  	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_current_state(TASK_RUNNING);
  			remove_wait_queue(&cc->write_thread_wait, &wait);
  			break;
  		}
  
  		schedule();
  
  		set_current_state(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)) {
  		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;
  	blk_status_t 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 = BLK_STS_IOERR;
  		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 = r;
  	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;
  	blk_status_t r;
  
  	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)
  		io->error = r;
  
  	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;
  
  	/*
  	 * A request from crypto driver backlog is going to be processed now,
  	 * finish the completion and continue in crypt_convert().
  	 * (Callback will be called for the second time for this request.)
  	 */
  	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, org_iv_of_dmreq(cc, dmreq), dmreq);
  
  	if (error == -EBADMSG) {
  		DMERR_LIMIT("INTEGRITY AEAD ERROR, sector %llu",
  			    (unsigned long long)le64_to_cpu(*org_sector_of_dmreq(cc, dmreq)));
  		io->error = BLK_STS_PROTECTION;
  	} else if (error < 0)
  		io->error = BLK_STS_IOERR;
  
  	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);
  }
  
  static void crypt_free_tfms_aead(struct crypt_config *cc)
  {
  	if (!cc->cipher_tfm.tfms_aead)
  		return;
  
  	if (cc->cipher_tfm.tfms_aead[0] && !IS_ERR(cc->cipher_tfm.tfms_aead[0])) {
  		crypto_free_aead(cc->cipher_tfm.tfms_aead[0]);
  		cc->cipher_tfm.tfms_aead[0] = NULL;
  	}
  
  	kfree(cc->cipher_tfm.tfms_aead);
  	cc->cipher_tfm.tfms_aead = NULL;
  }
  
  static void crypt_free_tfms_skcipher(struct crypt_config *cc)
  {
  	unsigned i;
  
  	if (!cc->cipher_tfm.tfms)
  		return;
  
  	for (i = 0; i < cc->tfms_count; i++)
  		if (cc->cipher_tfm.tfms[i] && !IS_ERR(cc->cipher_tfm.tfms[i])) {
  			crypto_free_skcipher(cc->cipher_tfm.tfms[i]);
  			cc->cipher_tfm.tfms[i] = NULL;
  		}
  
  	kfree(cc->cipher_tfm.tfms);
  	cc->cipher_tfm.tfms = NULL;
  }
  
  static void crypt_free_tfms(struct crypt_config *cc)
  {
  	if (crypt_integrity_aead(cc))
  		crypt_free_tfms_aead(cc);
  	else
  		crypt_free_tfms_skcipher(cc);
  }
  
  static int crypt_alloc_tfms_skcipher(struct crypt_config *cc, char *ciphermode)
  {
  	unsigned i;
  	int err;
  
  	cc->cipher_tfm.tfms = kzalloc(cc->tfms_count *
  				      sizeof(struct crypto_skcipher *), GFP_KERNEL);
  	if (!cc->cipher_tfm.tfms)
  		return -ENOMEM;
  
  	for (i = 0; i < cc->tfms_count; i++) {
  		cc->cipher_tfm.tfms[i] = crypto_alloc_skcipher(ciphermode, 0, 0);
  		if (IS_ERR(cc->cipher_tfm.tfms[i])) {
  			err = PTR_ERR(cc->cipher_tfm.tfms[i]);
  			crypt_free_tfms(cc);
  			return err;
  		}
  	}
  
  	return 0;
  }
  
  static int crypt_alloc_tfms_aead(struct crypt_config *cc, char *ciphermode)
  {
  	int err;
  
  	cc->cipher_tfm.tfms = kmalloc(sizeof(struct crypto_aead *), GFP_KERNEL);
  	if (!cc->cipher_tfm.tfms)
  		return -ENOMEM;
  
  	cc->cipher_tfm.tfms_aead[0] = crypto_alloc_aead(ciphermode, 0, 0);
  	if (IS_ERR(cc->cipher_tfm.tfms_aead[0])) {
  		err = PTR_ERR(cc->cipher_tfm.tfms_aead[0]);
  		crypt_free_tfms(cc);
  		return err;
  	}
  
  	return 0;
  }
  
  static int crypt_alloc_tfms(struct crypt_config *cc, char *ciphermode)
  {
  	if (crypt_integrity_aead(cc))
  		return crypt_alloc_tfms_aead(cc, ciphermode);
  	else
  		return crypt_alloc_tfms_skcipher(cc, ciphermode);
  }
  
  static unsigned crypt_subkey_size(struct crypt_config *cc)
  {
  	return (cc->key_size - cc->key_extra_size) >> ilog2(cc->tfms_count);
  }
  
  static unsigned crypt_authenckey_size(struct crypt_config *cc)
  {
  	return crypt_subkey_size(cc) + RTA_SPACE(sizeof(struct crypto_authenc_key_param));
  }
  
  /*
   * If AEAD is composed like authenc(hmac(sha256),xts(aes)),
   * the key must be for some reason in special format.
   * This funcion converts cc->key to this special format.
   */
  static void crypt_copy_authenckey(char *p, const void *key,
  				  unsigned enckeylen, unsigned authkeylen)
  {
  	struct crypto_authenc_key_param *param;
  	struct rtattr *rta;
  
  	rta = (struct rtattr *)p;
  	param = RTA_DATA(rta);
  	param->enckeylen = cpu_to_be32(enckeylen);
  	rta->rta_len = RTA_LENGTH(sizeof(*param));
  	rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
  	p += RTA_SPACE(sizeof(*param));
  	memcpy(p, key + enckeylen, authkeylen);
  	p += authkeylen;
  	memcpy(p, key, enckeylen);
  }
  
  static int crypt_setkey(struct crypt_config *cc)
  {
  	unsigned subkey_size;
  	int err = 0, i, r;
  
  	/* Ignore extra keys (which are used for IV etc) */
  	subkey_size = crypt_subkey_size(cc);
  
  	if (crypt_integrity_hmac(cc)) {
  		if (subkey_size < cc->key_mac_size)
  			return -EINVAL;
  
  		crypt_copy_authenckey(cc->authenc_key, cc->key,
  				      subkey_size - cc->key_mac_size,
  				      cc->key_mac_size);
  	}
  
  	for (i = 0; i < cc->tfms_count; i++) {
  		if (crypt_integrity_hmac(cc))
  			r = crypto_aead_setkey(cc->cipher_tfm.tfms_aead[i],
  				cc->authenc_key, crypt_authenckey_size(cc));
  		else if (crypt_integrity_aead(cc))
  			r = crypto_aead_setkey(cc->cipher_tfm.tfms_aead[i],
  					       cc->key + (i * subkey_size),
  					       subkey_size);
  		else
  			r = crypto_skcipher_setkey(cc->cipher_tfm.tfms[i],
  						   cc->key + (i * subkey_size),
  						   subkey_size);
  		if (r)
  			err = r;
  	}
  
  	if (crypt_integrity_hmac(cc))
  		memzero_explicit(cc->authenc_key, crypt_authenckey_size(cc));
  
  	return err;
  }
  
  #ifdef CONFIG_KEYS
  
  static bool contains_whitespace(const char *str)
  {
  	while (*str)
  		if (isspace(*str++))
  			return true;
  	return false;
  }
  
  static int crypt_set_keyring_key(struct crypt_config *cc, const char *key_string)
  {
  	char *new_key_string, *key_desc;
  	int ret;
  	struct key *key;
  	const struct user_key_payload *ukp;
  
  	/*
  	 * Reject key_string with whitespace. dm core currently lacks code for
  	 * proper whitespace escaping in arguments on DM_TABLE_STATUS path.
  	 */
  	if (contains_whitespace(key_string)) {
  		DMERR("whitespace chars not allowed in key string");
  		return -EINVAL;
  	}
  
  	/* look for next ':' separating key_type from key_description */
  	key_desc = strpbrk(key_string, ":");
  	if (!key_desc || key_desc == key_string || !strlen(key_desc + 1))
  		return -EINVAL;
  
  	if (strncmp(key_string, "logon:", key_desc - key_string + 1) &&
  	    strncmp(key_string, "user:", key_desc - key_string + 1))
  		return -EINVAL;
  
  	new_key_string = kstrdup(key_string, GFP_KERNEL);
  	if (!new_key_string)
  		return -ENOMEM;
  
  	key = request_key(key_string[0] == 'l' ? &key_type_logon : &key_type_user,
  			  key_desc + 1, NULL);
  	if (IS_ERR(key)) {
  		kzfree(new_key_string);
  		return PTR_ERR(key);
  	}
  
  	down_read(&key->sem);
  
  	ukp = user_key_payload_locked(key);
  	if (!ukp) {
  		up_read(&key->sem);
  		key_put(key);
  		kzfree(new_key_string);
  		return -EKEYREVOKED;
  	}
  
  	if (cc->key_size != ukp->datalen) {
  		up_read(&key->sem);
  		key_put(key);
  		kzfree(new_key_string);
  		return -EINVAL;
  	}
  
  	memcpy(cc->key, ukp->data, cc->key_size);
  
  	up_read(&key->sem);
  	key_put(key);
  
  	/* clear the flag since following operations may invalidate previously valid key */
  	clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
  
  	ret = crypt_setkey(cc);
  
  	if (!ret) {
  		set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
  		kzfree(cc->key_string);
  		cc->key_string = new_key_string;
  	} else
  		kzfree(new_key_string);
  
  	return ret;
  }
  
  static int get_key_size(char **key_string)
  {
  	char *colon, dummy;
  	int ret;
  
  	if (*key_string[0] != ':')
  		return strlen(*key_string) >> 1;
  
  	/* look for next ':' in key string */
  	colon = strpbrk(*key_string + 1, ":");
  	if (!colon)
  		return -EINVAL;
  
  	if (sscanf(*key_string + 1, "%u%c", &ret, &dummy) != 2 || dummy != ':')
  		return -EINVAL;
  
  	*key_string = colon;
  
  	/* remaining key string should be :<logon|user>:<key_desc> */
  
  	return ret;
  }
  
  #else
  
  static int crypt_set_keyring_key(struct crypt_config *cc, const char *key_string)
  {
  	return -EINVAL;
  }
  
  static int get_key_size(char **key_string)
  {
  	return (*key_string[0] == ':') ? -EINVAL : strlen(*key_string) >> 1;
  }
  
  #endif
  
  static int crypt_set_key(struct crypt_config *cc, char *key)
  {
  	int r = -EINVAL;
  	int key_string_len = strlen(key);
  
  	/* Hyphen (which gives a key_size of zero) means there is no key. */
  	if (!cc->key_size && strcmp(key, "-"))
  		goto out;
  
  	/* ':' means the key is in kernel keyring, short-circuit normal key processing */
  	if (key[0] == ':') {
  		r = crypt_set_keyring_key(cc, key + 1);
  		goto out;
  	}
  
  	/* clear the flag since following operations may invalidate previously valid key */
  	clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
  
  	/* wipe references to any kernel keyring key */
  	kzfree(cc->key_string);
  	cc->key_string = NULL;
  
  	/* Decode key from its hex representation. */
  	if (cc->key_size && hex2bin(cc->key, key, cc->key_size) < 0)
  		goto out;
  
  	r = crypt_setkey(cc);
  	if (!r)
  		set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
  
  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)
  {
  	int r;
  
  	clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
  	get_random_bytes(&cc->key, cc->key_size);
  	kzfree(cc->key_string);
  	cc->key_string = NULL;
  	r = crypt_setkey(cc);
  	memset(&cc->key, 0, cc->key_size * sizeof(u8));
  
  	return r;
  }
  
  static void crypt_calculate_pages_per_client(void)
  {
  	unsigned long pages = (totalram_pages - totalhigh_pages) * DM_CRYPT_MEMORY_PERCENT / 100;
  
  	if (!dm_crypt_clients_n)
  		return;
  
  	pages /= dm_crypt_clients_n;
  	if (pages < DM_CRYPT_MIN_PAGES_PER_CLIENT)
  		pages = DM_CRYPT_MIN_PAGES_PER_CLIENT;
  	dm_crypt_pages_per_client = pages;
  }
  
  static void *crypt_page_alloc(gfp_t gfp_mask, void *pool_data)
  {
  	struct crypt_config *cc = pool_data;
  	struct page *page;
  
  	if (unlikely(percpu_counter_compare(&cc->n_allocated_pages, dm_crypt_pages_per_client) >= 0) &&
  	    likely(gfp_mask & __GFP_NORETRY))
  		return NULL;
  
  	page = alloc_page(gfp_mask);
  	if (likely(page != NULL))
  		percpu_counter_add(&cc->n_allocated_pages, 1);
  
  	return page;
  }
  
  static void crypt_page_free(void *page, void *pool_data)
  {
  	struct crypt_config *cc = pool_data;
  
  	__free_page(page);
  	percpu_counter_sub(&cc->n_allocated_pages, 1);
  }
  
  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);
  
  	mempool_destroy(cc->page_pool);
  	mempool_destroy(cc->req_pool);
  	mempool_destroy(cc->tag_pool);
  
  	if (cc->page_pool)
  		WARN_ON(percpu_counter_sum(&cc->n_allocated_pages) != 0);
  	percpu_counter_destroy(&cc->n_allocated_pages);
  
  	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);
  	kzfree(cc->key_string);
  	kzfree(cc->cipher_auth);
  	kzfree(cc->authenc_key);
  
  	mutex_destroy(&cc->bio_alloc_lock);
  
  	/* Must zero key material before freeing */
  	kzfree(cc);
  
  	spin_lock(&dm_crypt_clients_lock);
  	WARN_ON(!dm_crypt_clients_n);
  	dm_crypt_clients_n--;
  	crypt_calculate_pages_per_client();
  	spin_unlock(&dm_crypt_clients_lock);
  }
  
  static int crypt_ctr_ivmode(struct dm_target *ti, const char *ivmode)
  {
  	struct crypt_config *cc = ti->private;
  
  	if (crypt_integrity_aead(cc))
  		cc->iv_size = crypto_aead_ivsize(any_tfm_aead(cc));
  	else
  		cc->iv_size = crypto_skcipher_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, "plain64be") == 0)
  		cc->iv_gen_ops = &crypt_iv_plain64be_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 if (strcmp(ivmode, "random") == 0) {
  		cc->iv_gen_ops = &crypt_iv_random_ops;
  		/* Need storage space in integrity fields. */
  		cc->integrity_iv_size = cc->iv_size;
  	} else {
  		ti->error = "Invalid IV mode";
  		return -EINVAL;
  	}
  
  	return 0;
  }
  
  /*
   * Workaround to parse cipher algorithm from crypto API spec.
   * The cc->cipher is currently used only in ESSIV.
   * This should be probably done by crypto-api calls (once available...)
   */
  static int crypt_ctr_blkdev_cipher(struct crypt_config *cc)
  {
  	const char *alg_name = NULL;
  	char *start, *end;
  
  	if (crypt_integrity_aead(cc)) {
  		alg_name = crypto_tfm_alg_name(crypto_aead_tfm(any_tfm_aead(cc)));
  		if (!alg_name)
  			return -EINVAL;
  		if (crypt_integrity_hmac(cc)) {
  			alg_name = strchr(alg_name, ',');
  			if (!alg_name)
  				return -EINVAL;
  		}
  		alg_name++;
  	} else {
  		alg_name = crypto_tfm_alg_name(crypto_skcipher_tfm(any_tfm(cc)));
  		if (!alg_name)
  			return -EINVAL;
  	}
  
  	start = strchr(alg_name, '(');
  	end = strchr(alg_name, ')');
  
  	if (!start && !end) {
  		cc->cipher = kstrdup(alg_name, GFP_KERNEL);
  		return cc->cipher ? 0 : -ENOMEM;
  	}
  
  	if (!start || !end || ++start >= end)
  		return -EINVAL;
  
  	cc->cipher = kzalloc(end - start + 1, GFP_KERNEL);
  	if (!cc->cipher)
  		return -ENOMEM;
  
  	strncpy(cc->cipher, start, end - start);
  
  	return 0;
  }
  
  /*
   * Workaround to parse HMAC algorithm from AEAD crypto API spec.
   * The HMAC is needed to calculate tag size (HMAC digest size).
   * This should be probably done by crypto-api calls (once available...)
   */
  static int crypt_ctr_auth_cipher(struct crypt_config *cc, char *cipher_api)
  {
  	char *start, *end, *mac_alg = NULL;
  	struct crypto_ahash *mac;
  
  	if (!strstarts(cipher_api, "authenc("))
  		return 0;
  
  	start = strchr(cipher_api, '(');
  	end = strchr(cipher_api, ',');
  	if (!start || !end || ++start > end)
  		return -EINVAL;
  
  	mac_alg = kzalloc(end - start + 1, GFP_KERNEL);
  	if (!mac_alg)
  		return -ENOMEM;
  	strncpy(mac_alg, start, end - start);
  
  	mac = crypto_alloc_ahash(mac_alg, 0, 0);
  	kfree(mac_alg);
  
  	if (IS_ERR(mac))
  		return PTR_ERR(mac);
  
  	cc->key_mac_size = crypto_ahash_digestsize(mac);
  	crypto_free_ahash(mac);
  
  	cc->authenc_key = kmalloc(crypt_authenckey_size(cc), GFP_KERNEL);
  	if (!cc->authenc_key)
  		return -ENOMEM;
  
  	return 0;
  }
  
  static int crypt_ctr_cipher_new(struct dm_target *ti, char *cipher_in, char *key,
  				char **ivmode, char **ivopts)
  {
  	struct crypt_config *cc = ti->private;
  	char *tmp, *cipher_api;
  	int ret = -EINVAL;
  
  	cc->tfms_count = 1;
  
  	/*
  	 * New format (capi: prefix)
  	 * capi:cipher_api_spec-iv:ivopts
  	 */
  	tmp = &cipher_in[strlen("capi:")];
  	cipher_api = strsep(&tmp, "-");
  	*ivmode = strsep(&tmp, ":");
  	*ivopts = tmp;
  
  	if (*ivmode && !strcmp(*ivmode, "lmk"))
  		cc->tfms_count = 64;
  
  	cc->key_parts = cc->tfms_count;
  
  	/* Allocate cipher */
  	ret = crypt_alloc_tfms(cc, cipher_api);
  	if (ret < 0) {
  		ti->error = "Error allocating crypto tfm";
  		return ret;
  	}
  
  	/* Alloc AEAD, can be used only in new format. */
  	if (crypt_integrity_aead(cc)) {
  		ret = crypt_ctr_auth_cipher(cc, cipher_api);
  		if (ret < 0) {
  			ti->error = "Invalid AEAD cipher spec";
  			return -ENOMEM;
  		}
  		cc->iv_size = crypto_aead_ivsize(any_tfm_aead(cc));
  	} else
  		cc->iv_size = crypto_skcipher_ivsize(any_tfm(cc));
  
  	ret = crypt_ctr_blkdev_cipher(cc);
  	if (ret < 0) {
  		ti->error = "Cannot allocate cipher string";
  		return -ENOMEM;
  	}
  
  	return 0;
  }
  
  static int crypt_ctr_cipher_old(struct dm_target *ti, char *cipher_in, char *key,
  				char **ivmode, char **ivopts)
  {
  	struct crypt_config *cc = ti->private;
  	char *tmp, *cipher, *chainmode, *keycount;
  	char *cipher_api = NULL;
  	int ret = -EINVAL;
  	char dummy;
  
  	if (strchr(cipher_in, '(') || crypt_integrity_aead(cc)) {
  		ti->error = "Bad cipher specification";
  		return -EINVAL;
  	}
  
  	/*
  	 * 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->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";
  		kfree(cipher_api);
  		return ret;
  	}
  	kfree(cipher_api);
  
  	return 0;
  bad_mem:
  	ti->error = "Cannot allocate cipher strings";
  	return -ENOMEM;
  }
  
  static int crypt_ctr_cipher(struct dm_target *ti, char *cipher_in, char *key)
  {
  	struct crypt_config *cc = ti->private;
  	char *ivmode = NULL, *ivopts = NULL;
  	int ret;
  
  	cc->cipher_string = kstrdup(cipher_in, GFP_KERNEL);
  	if (!cc->cipher_string) {
  		ti->error = "Cannot allocate cipher strings";
  		return -ENOMEM;
  	}
  
  	if (strstarts(cipher_in, "capi:"))
  		ret = crypt_ctr_cipher_new(ti, cipher_in, key, &ivmode, &ivopts);
  	else
  		ret = crypt_ctr_cipher_old(ti, cipher_in, key, &ivmode, &ivopts);
  	if (ret)
  		return ret;
  
  	/* Initialize IV */
  	ret = crypt_ctr_ivmode(ti, ivmode);
  	if (ret < 0)
  		return ret;
  
  	/* Initialize and set key */
  	ret = crypt_set_key(cc, key);
  	if (ret < 0) {
  		ti->error = "Error decoding and setting key";
  		return ret;
  	}
  
  	/* 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";
  			return ret;
  		}
  	}
  
  	/* 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";
  			return ret;
  		}
  	}
  
  	/* wipe the kernel key payload copy */
  	if (cc->key_string)
  		memset(cc->key, 0, cc->key_size * sizeof(u8));
  
  	return ret;
  }
  
  static int crypt_ctr_optional(struct dm_target *ti, unsigned int argc, char **argv)
  {
  	struct crypt_config *cc = ti->private;
  	struct dm_arg_set as;
  	static const struct dm_arg _args[] = {
  		{0, 6, "Invalid number of feature args"},
  	};
  	unsigned int opt_params, val;
  	const char *opt_string, *sval;
  	char dummy;
  	int ret;
  
  	/* Optional parameters */
  	as.argc = argc;
  	as.argv = argv;
  
  	ret = dm_read_arg_group(_args, &as, &opt_params, &ti->error);
  	if (ret)
  		return ret;
  
  	while (opt_params--) {
  		opt_string = dm_shift_arg(&as);
  		if (!opt_string) {
  			ti->error = "Not enough feature arguments";
  			return -EINVAL;
  		}
  
  		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 if (sscanf(opt_string, "integrity:%u:", &val) == 1) {
  			if (val == 0 || val > MAX_TAG_SIZE) {
  				ti->error = "Invalid integrity arguments";
  				return -EINVAL;
  			}
  			cc->on_disk_tag_size = val;
  			sval = strchr(opt_string + strlen("integrity:"), ':') + 1;
  			if (!strcasecmp(sval, "aead")) {
  				set_bit(CRYPT_MODE_INTEGRITY_AEAD, &cc->cipher_flags);
  			} else  if (strcasecmp(sval, "none")) {
  				ti->error = "Unknown integrity profile";
  				return -EINVAL;
  			}
  
  			cc->cipher_auth = kstrdup(sval, GFP_KERNEL);
  			if (!cc->cipher_auth)
  				return -ENOMEM;
  		} else if (sscanf(opt_string, "sector_size:%hu%c", &cc->sector_size, &dummy) == 1) {
  			if (cc->sector_size < (1 << SECTOR_SHIFT) ||
  			    cc->sector_size > 4096 ||
  			    (cc->sector_size & (cc->sector_size - 1))) {
  				ti->error = "Invalid feature value for sector_size";
  				return -EINVAL;
  			}
  			if (ti->len & ((cc->sector_size >> SECTOR_SHIFT) - 1)) {
  				ti->error = "Device size is not multiple of sector_size feature";
  				return -EINVAL;
  			}
  			cc->sector_shift = __ffs(cc->sector_size) - SECTOR_SHIFT;
  		} else if (!strcasecmp(opt_string, "iv_large_sectors"))
  			set_bit(CRYPT_IV_LARGE_SECTORS, &cc->cipher_flags);
  		else {
  			ti->error = "Invalid feature arguments";
  			return -EINVAL;
  		}
  	}
  
  	return 0;
  }
  
  /*
   * Construct an encryption mapping:
   * <cipher> [<key>|:<key_size>:<user|logon>:<key_description>] <iv_offset> <dev_path> <start>
   */
  static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
  {
  	struct crypt_config *cc;
  	int key_size;
  	unsigned int align_mask;
  	unsigned long long tmpll;
  	int ret;
  	size_t iv_size_padding, additional_req_size;
  	char dummy;
  
  	if (argc < 5) {
  		ti->error = "Not enough arguments";
  		return -EINVAL;
  	}
  
  	key_size = get_key_size(&argv[1]);
  	if (key_size < 0) {
  		ti->error = "Cannot parse key size";
  		return -EINVAL;
  	}
  
  	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;
  	cc->sector_size = (1 << SECTOR_SHIFT);
  	cc->sector_shift = 0;
  
  	ti->private = cc;
  
  	spin_lock(&dm_crypt_clients_lock);
  	dm_crypt_clients_n++;
  	crypt_calculate_pages_per_client();
  	spin_unlock(&dm_crypt_clients_lock);
  
  	ret = percpu_counter_init(&cc->n_allocated_pages, 0, GFP_KERNEL);
  	if (ret < 0)
  		goto bad;
  
  	/* Optional parameters need to be read before cipher constructor */
  	if (argc > 5) {
  		ret = crypt_ctr_optional(ti, argc - 5, &argv[5]);
  		if (ret)
  			goto bad;
  	}
  
  	ret = crypt_ctr_cipher(ti, argv[0], argv[1]);
  	if (ret < 0)
  		goto bad;
  
  	if (crypt_integrity_aead(cc)) {
  		cc->dmreq_start = sizeof(struct aead_request);
  		cc->dmreq_start += crypto_aead_reqsize(any_tfm_aead(cc));
  		align_mask = crypto_aead_alignmask(any_tfm_aead(cc));
  	} else {
  		cc->dmreq_start = sizeof(struct skcipher_request);
  		cc->dmreq_start += crypto_skcipher_reqsize(any_tfm(cc));
  		align_mask = crypto_skcipher_alignmask(any_tfm(cc));
  	}
  	cc->dmreq_start = ALIGN(cc->dmreq_start, __alignof__(struct dm_crypt_request));
  
  	if (align_mask < CRYPTO_MINALIGN) {
  		/* Allocate the padding exactly */
  		iv_size_padding = -(cc->dmreq_start + sizeof(struct dm_crypt_request))
  				& align_mask;
  	} 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 = align_mask;
  	}
  
  	ret = -ENOMEM;
  
  	/*  ...| IV + padding | original IV | original sec. number | bio tag offset | */
  	additional_req_size = sizeof(struct dm_crypt_request) +
  		iv_size_padding + cc->iv_size +
  		cc->iv_size +
  		sizeof(uint64_t) +
  		sizeof(unsigned int);
  
  	cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start + additional_req_size);
  	if (!cc->req_pool) {
  		ti->error = "Cannot allocate crypt request mempool";
  		goto bad;
  	}
  
  	cc->per_bio_data_size = ti->per_io_data_size =
  		ALIGN(sizeof(struct dm_crypt_io) + cc->dmreq_start + additional_req_size,
  		      ARCH_KMALLOC_MINALIGN);
  
  	cc->page_pool = mempool_create(BIO_MAX_PAGES, crypt_page_alloc, crypt_page_free, cc);
  	if (!cc->page_pool) {
  		ti->error = "Cannot allocate page mempool";
  		goto bad;
  	}
  
  	cc->bs = bioset_create(MIN_IOS, 0, BIOSET_NEED_BVECS);
  	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) ||
  	    (tmpll & ((cc->sector_size >> SECTOR_SHIFT) - 1))) {
  		ti->error = "Invalid iv_offset sector";
  		goto bad;
  	}
  	cc->iv_offset = tmpll;
  
  	ret = dm_get_device(ti, argv[3], dm_table_get_mode(ti->table), &cc->dev);
  	if (ret) {
  		ti->error = "Device lookup failed";
  		goto bad;
  	}
  
  	ret = -EINVAL;
  	if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1) {
  		ti->error = "Invalid device sector";
  		goto bad;
  	}
  	cc->start = tmpll;
  
  	if (crypt_integrity_aead(cc) || cc->integrity_iv_size) {
  		ret = crypt_integrity_ctr(cc, ti);
  		if (ret)
  			goto bad;
  
  		cc->tag_pool_max_sectors = POOL_ENTRY_SIZE / cc->on_disk_tag_size;
  		if (!cc->tag_pool_max_sectors)
  			cc->tag_pool_max_sectors = 1;
  
  		cc->tag_pool = mempool_create_kmalloc_pool(MIN_IOS,
  			cc->tag_pool_max_sectors * cc->on_disk_tag_size);
  		if (!cc->tag_pool) {
  			ti->error = "Cannot allocate integrity tags mempool";
  			ret = -ENOMEM;
  			goto bad;
  		}
  
  		cc->tag_pool_max_sectors <<= cc->sector_shift;
  	}
  
  	ret = -ENOMEM;
  	cc->io_queue = alloc_workqueue("kcryptd_io", WQ_HIGHPRI | WQ_CPU_INTENSIVE | 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_HIGHPRI | WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM, 1);
  	else
  		cc->crypt_queue = alloc_workqueue("kcryptd",
  						  WQ_HIGHPRI | 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;
  
  	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_PREFLUSH or REQ_OP_DISCARD, just bypass crypt queues.
  	 * - for REQ_PREFLUSH device-mapper core ensures that no IO is in-flight
  	 * - for REQ_OP_DISCARD caller must use flush if IO ordering matters
  	 */
  	if (unlikely(bio->bi_opf & REQ_PREFLUSH ||
  	    bio_op(bio) == REQ_OP_DISCARD)) {
  		bio_set_dev(bio, 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;
  	}
  
  	/*
  	 * Check if bio is too large, split as needed.
  	 */
  	if (unlikely(bio->bi_iter.bi_size > (BIO_MAX_PAGES << PAGE_SHIFT)) &&
  	    (bio_data_dir(bio) == WRITE || cc->on_disk_tag_size))
  		dm_accept_partial_bio(bio, ((BIO_MAX_PAGES << PAGE_SHIFT) >> SECTOR_SHIFT));
  
  	/*
  	 * Ensure that bio is a multiple of internal sector encryption size
  	 * and is aligned to this size as defined in IO hints.
  	 */
  	if (unlikely((bio->bi_iter.bi_sector & ((cc->sector_size >> SECTOR_SHIFT) - 1)) != 0))
  		return DM_MAPIO_KILL;
  
  	if (unlikely(bio->bi_iter.bi_size & (cc->sector_size - 1)))
  		return DM_MAPIO_KILL;
  
  	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));
  
  	if (cc->on_disk_tag_size) {
  		unsigned tag_len = cc->on_disk_tag_size * (bio_sectors(bio) >> cc->sector_shift);
  
  		if (unlikely(tag_len > KMALLOC_MAX_SIZE) ||
  		    unlikely(!(io->integrity_metadata = kmalloc(tag_len,
  				GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN)))) {
  			if (bio_sectors(bio) > cc->tag_pool_max_sectors)
  				dm_accept_partial_bio(bio, cc->tag_pool_max_sectors);
  			io->integrity_metadata = mempool_alloc(cc->tag_pool, GFP_NOIO);
  			io->integrity_metadata_from_pool = true;
  		}
  	}
  
  	if (crypt_integrity_aead(cc))
  		io->ctx.r.req_aead = (struct aead_request *)(io + 1);
  	else
  		io->ctx.r.req = (struct skcipher_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) {
  			if (cc->key_string)
  				DMEMIT(":%u:%s", cc->key_size, cc->key_string);
  			else
  				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);
  		num_feature_args += cc->sector_size != (1 << SECTOR_SHIFT);
  		num_feature_args += test_bit(CRYPT_IV_LARGE_SECTORS, &cc->cipher_flags);
  		if (cc->on_disk_tag_size)
  			num_feature_args++;
  		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");
  			if (cc->on_disk_tag_size)
  				DMEMIT(" integrity:%u:%s", cc->on_disk_tag_size, cc->cipher_auth);
  			if (cc->sector_size != (1 << SECTOR_SHIFT))
  				DMEMIT(" sector_size:%d", cc->sector_size);
  			if (test_bit(CRYPT_IV_LARGE_SECTORS, &cc->cipher_flags))
  				DMEMIT(" iv_large_sectors");
  		}
  
  		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,
  			 char *result, unsigned maxlen)
  {
  	struct crypt_config *cc = ti->private;
  	int key_size, 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")) {
  			/* The key size may not be changed. */
  			key_size = get_key_size(&argv[2]);
  			if (key_size < 0 || cc->key_size != key_size) {
  				memset(argv[2], '0', strlen(argv[2]));
  				return -EINVAL;
  			}
  
  			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);
  			/* wipe the kernel key payload copy */
  			if (cc->key_string)
  				memset(cc->key, 0, cc->key_size * sizeof(u8));
  			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_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 void crypt_io_hints(struct dm_target *ti, struct queue_limits *limits)
  {
  	struct crypt_config *cc = ti->private;
  
  	/*
  	 * Unfortunate constraint that is required to avoid the potential
  	 * for exceeding underlying device's max_segments limits -- due to
  	 * crypt_alloc_buffer() possibly allocating pages for the encryption
  	 * bio that are not as physically contiguous as the original bio.
  	 */
  	limits->max_segment_size = PAGE_SIZE;
  
  	if (cc->sector_size != (1 << SECTOR_SHIFT)) {
  		limits->logical_block_size = cc->sector_size;
  		limits->physical_block_size = cc->sector_size;
  		blk_limits_io_min(limits, cc->sector_size);
  	}
  }
  
  static struct target_type crypt_target = {
  	.name   = "crypt",
  	.version = {1, 18, 1},
  	.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,
  	.iterate_devices = crypt_iterate_devices,
  	.io_hints = crypt_io_hints,
  };
  
  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");
  