/* * Copyright (C) 2003 Christophe Saout <christophe@saout.de> * Copyright (C) 2004 Clemens Fruhwirth <clemens@endorphin.org> * Copyright (C) 2006-2009 Red Hat, Inc. All rights reserved. * * 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/backing-dev.h> #include <linux/percpu.h> #include <linux/atomic.h> #include <linux/scatterlist.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; unsigned int offset_in; unsigned int offset_out; unsigned int idx_in; unsigned int idx_out; sector_t cc_sector; atomic_t cc_pending; }; /* * 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 dm_crypt_io *base_io; }; 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; }; /* * 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 }; /* * Duplicated per-CPU state for cipher. */ struct crypt_cpu { struct ablkcipher_request *req; }; /* * The fields in here must be read only after initialization, * changing state should be in crypt_cpu. */ 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 *io_pool; mempool_t *req_pool; mempool_t *page_pool; struct bio_set *bs; struct workqueue_struct *io_queue; struct workqueue_struct *crypt_queue; 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; } iv_gen_private; sector_t iv_offset; unsigned int iv_size; /* * Duplicated per cpu state. Access through * per_cpu_ptr() only. */ struct crypt_cpu __percpu *cpu; /* 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 long flags; unsigned int key_size; unsigned int key_parts; u8 key[0]; }; #define MIN_IOS 16 #define MIN_POOL_PAGES 32 static struct kmem_cache *_crypt_io_pool; 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); static struct crypt_cpu *this_crypt_config(struct crypt_config *cc) { return this_cpu_ptr(cc->cpu); } /* * 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) * * 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; struct { struct shash_desc desc; char ctx[crypto_shash_descsize(lmk->hash_tfm)]; } sdesc; struct md5_state md5state; u32 buf[4]; int i, r; sdesc.desc.tfm = lmk->hash_tfm; sdesc.desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; r = crypto_shash_init(&sdesc.desc); if (r) return r; if (lmk->seed) { r = crypto_shash_update(&sdesc.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(&sdesc.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(&sdesc.desc, (u8 *)buf, sizeof(buf)); if (r) return r; /* No MD5 padding here */ r = crypto_shash_export(&sdesc.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 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 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; ctx->offset_in = 0; ctx->offset_out = 0; ctx->idx_in = bio_in ? bio_in->bi_idx : 0; ctx->idx_out = bio_out ? bio_out->bi_idx : 0; 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_iovec_idx(ctx->bio_in, ctx->idx_in); struct bio_vec *bv_out = bio_iovec_idx(ctx->bio_out, ctx->idx_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 + ctx->offset_in); sg_init_table(&dmreq->sg_out, 1); sg_set_page(&dmreq->sg_out, bv_out->bv_page, 1 << SECTOR_SHIFT, bv_out->bv_offset + ctx->offset_out); ctx->offset_in += 1 << SECTOR_SHIFT; if (ctx->offset_in >= bv_in->bv_len) { ctx->offset_in = 0; ctx->idx_in++; } ctx->offset_out += 1 << SECTOR_SHIFT; if (ctx->offset_out >= bv_out->bv_len) { ctx->offset_out = 0; ctx->idx_out++; } 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) { struct crypt_cpu *this_cc = this_crypt_config(cc); unsigned key_index = ctx->cc_sector & (cc->tfms_count - 1); if (!this_cc->req) this_cc->req = mempool_alloc(cc->req_pool, GFP_NOIO); ablkcipher_request_set_tfm(this_cc->req, cc->tfms[key_index]); ablkcipher_request_set_callback(this_cc->req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, kcryptd_async_done, dmreq_of_req(cc, this_cc->req)); } /* * 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) { struct crypt_cpu *this_cc = this_crypt_config(cc); int r; atomic_set(&ctx->cc_pending, 1); while(ctx->idx_in < ctx->bio_in->bi_vcnt && ctx->idx_out < ctx->bio_out->bi_vcnt) { crypt_alloc_req(cc, ctx); atomic_inc(&ctx->cc_pending); r = crypt_convert_block(cc, ctx, this_cc->req); switch (r) { /* async */ case -EBUSY: wait_for_completion(&ctx->restart); INIT_COMPLETION(ctx->restart); /* fall through*/ case -EINPROGRESS: this_cc->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; } /* * Generate a new unfragmented bio with the given size * This should never violate the device limitations * May return a smaller bio when running out of pages, indicated by * *out_of_pages set to 1. */ static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size, unsigned *out_of_pages) { struct crypt_config *cc = io->cc; struct bio *clone; unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM; unsigned i, len; struct page *page; clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs); if (!clone) return NULL; clone_init(io, clone); *out_of_pages = 0; for (i = 0; i < nr_iovecs; i++) { page = mempool_alloc(cc->page_pool, gfp_mask); if (!page) { *out_of_pages = 1; break; } /* * If additional pages cannot be allocated without waiting, * return a partially-allocated bio. The caller will then try * to allocate more bios while submitting this partial bio. */ gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT; len = (size > PAGE_SIZE) ? PAGE_SIZE : size; if (!bio_add_page(clone, page, len, 0)) { mempool_free(page, cc->page_pool); break; } size -= len; } if (!clone->bi_size) { bio_put(clone); return NULL; } return clone; } static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone) { unsigned int i; struct bio_vec *bv; for (i = 0; i < clone->bi_vcnt; i++) { bv = bio_iovec_idx(clone, i); BUG_ON(!bv->bv_page); mempool_free(bv->bv_page, cc->page_pool); bv->bv_page = NULL; } } static struct dm_crypt_io *crypt_io_alloc(struct crypt_config *cc, struct bio *bio, sector_t sector) { struct dm_crypt_io *io; io = mempool_alloc(cc->io_pool, GFP_NOIO); io->cc = cc; io->base_bio = bio; io->sector = sector; io->error = 0; io->base_io = NULL; atomic_set(&io->io_pending, 0); return io; } 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. * If base_io is set, wait for the last fragment to complete. */ static void crypt_dec_pending(struct dm_crypt_io *io) { struct crypt_config *cc = io->cc; struct bio *base_bio = io->base_bio; struct dm_crypt_io *base_io = io->base_io; int error = io->error; if (!atomic_dec_and_test(&io->io_pending)) return; mempool_free(io, cc->io_pool); if (likely(!base_io)) bio_endio(base_bio, error); else { if (error && !base_io->error) base_io->error = error; crypt_dec_pending(base_io); } } /* * 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 *base_bio = io->base_bio; struct bio *clone; /* * The block layer might modify the bvec array, so always * copy the required bvecs because we need the original * one in order to decrypt the whole bio data *afterwards*. */ clone = bio_clone_bioset(base_bio, gfp, cc->bs); if (!clone) return 1; crypt_inc_pending(io); clone_init(io, clone); clone->bi_sector = cc->start + io->sector; generic_make_request(clone); return 0; } static void kcryptd_io_write(struct dm_crypt_io *io) { struct bio *clone = io->ctx.bio_out; generic_make_request(clone); } static void kcryptd_io(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) { crypt_inc_pending(io); if (kcryptd_io_read(io, GFP_NOIO)) io->error = -ENOMEM; crypt_dec_pending(io); } else kcryptd_io_write(io); } static void kcryptd_queue_io(struct dm_crypt_io *io) { struct crypt_config *cc = io->cc; INIT_WORK(&io->work, kcryptd_io); queue_work(cc->io_queue, &io->work); } 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; 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.idx_out < clone->bi_vcnt); clone->bi_sector = cc->start + io->sector; if (async) kcryptd_queue_io(io); else generic_make_request(clone); } static void kcryptd_crypt_write_convert(struct dm_crypt_io *io) { struct crypt_config *cc = io->cc; struct bio *clone; struct dm_crypt_io *new_io; int crypt_finished; unsigned out_of_pages = 0; unsigned remaining = io->base_bio->bi_size; 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); /* * The allocated buffers can be smaller than the whole bio, * so repeat the whole process until all the data can be handled. */ while (remaining) { clone = crypt_alloc_buffer(io, remaining, &out_of_pages); if (unlikely(!clone)) { io->error = -ENOMEM; break; } io->ctx.bio_out = clone; io->ctx.idx_out = 0; remaining -= clone->bi_size; sector += bio_sectors(clone); crypt_inc_pending(io); r = crypt_convert(cc, &io->ctx); if (r < 0) 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); /* * If there was an error, do not try next fragments. * For async, error is processed in async handler. */ if (unlikely(r < 0)) break; io->sector = sector; } /* * Out of memory -> run queues * But don't wait if split was due to the io size restriction */ if (unlikely(out_of_pages)) congestion_wait(BLK_RW_ASYNC, HZ/100); /* * With async crypto it is unsafe to share the crypto context * between fragments, so switch to a new dm_crypt_io structure. */ if (unlikely(!crypt_finished && remaining)) { new_io = crypt_io_alloc(io->cc, io->base_bio, sector); crypt_inc_pending(new_io); crypt_convert_init(cc, &new_io->ctx, NULL, io->base_bio, sector); new_io->ctx.idx_in = io->ctx.idx_in; new_io->ctx.offset_in = io->ctx.offset_in; /* * Fragments after the first use the base_io * pending count. */ if (!io->base_io) new_io->base_io = io; else { new_io->base_io = io->base_io; crypt_inc_pending(io->base_io); crypt_dec_pending(io); } io = new_io; } } 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; mempool_free(req_of_dmreq(cc, dmreq), cc->req_pool); 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; } /* * Encode key into its hex representation */ static void crypt_encode_key(char *hex, u8 *key, unsigned int size) { unsigned int i; for (i = 0; i < size; i++) { sprintf(hex, "%02x", *key); hex += 2; key++; } } 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 = cc->key_size >> ilog2(cc->tfms_count); int err = 0, i, r; 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; struct crypt_cpu *cpu_cc; int cpu; ti->private = NULL; if (!cc) return; if (cc->io_queue) destroy_workqueue(cc->io_queue); if (cc->crypt_queue) destroy_workqueue(cc->crypt_queue); if (cc->cpu) for_each_possible_cpu(cpu) { cpu_cc = per_cpu_ptr(cc->cpu, cpu); if (cpu_cc->req) mempool_free(cpu_cc->req, cc->req_pool); } 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->io_pool) mempool_destroy(cc->io_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); if (cc->cpu) free_percpu(cc->cpu); 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->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"); cc->cpu = __alloc_percpu(sizeof(*(cc->cpu)), __alignof__(struct crypt_cpu)); if (!cc->cpu) { ti->error = "Cannot allocate per cpu state"; goto bad_mem; } /* * 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 and set key */ ret = crypt_set_key(cc, key); if (ret < 0) { ti->error = "Error decoding and setting key"; 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. */ if (cc->key_size % cc->key_parts) cc->key_parts++; } else { ret = -EINVAL; ti->error = "Invalid IV mode"; 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; struct dm_arg_set as; const char *opt_string; char dummy; static struct dm_arg _args[] = { {0, 1, "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; ret = -ENOMEM; cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool); if (!cc->io_pool) { ti->error = "Cannot allocate crypt io mempool"; 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, crypto_tfm_ctx_alignment()); cc->dmreq_start += crypto_ablkcipher_alignmask(any_tfm(cc)) & ~(crypto_tfm_ctx_alignment() - 1); cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start + sizeof(struct dm_crypt_request) + cc->iv_size); if (!cc->req_pool) { ti->error = "Cannot allocate crypt request mempool"; goto bad; } cc->page_pool = mempool_create_page_pool(MIN_POOL_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; } 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; opt_string = dm_shift_arg(&as); if (opt_params == 1 && opt_string && !strcasecmp(opt_string, "allow_discards")) ti->num_discard_requests = 1; else if (opt_params) { ret = -EINVAL; ti->error = "Invalid feature arguments"; goto bad; } } ret = -ENOMEM; cc->io_queue = alloc_workqueue("kcryptd_io", WQ_NON_REENTRANT| WQ_MEM_RECLAIM, 1); if (!cc->io_queue) { ti->error = "Couldn't create kcryptd io queue"; goto bad; } cc->crypt_queue = alloc_workqueue("kcryptd", WQ_NON_REENTRANT| WQ_CPU_INTENSIVE| WQ_MEM_RECLAIM, 1); if (!cc->crypt_queue) { ti->error = "Couldn't create kcryptd queue"; goto bad; } ti->num_flush_requests = 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_sector = cc->start + dm_target_offset(ti, bio->bi_sector); return DM_MAPIO_REMAPPED; } io = crypt_io_alloc(cc, bio, dm_target_offset(ti, bio->bi_sector)); if (bio_data_dir(io->base_bio) == READ) { if (kcryptd_io_read(io, GFP_NOWAIT)) kcryptd_queue_io(io); } else kcryptd_queue_crypt(io); return DM_MAPIO_SUBMITTED; } static int crypt_status(struct dm_target *ti, status_type_t type, unsigned status_flags, char *result, unsigned maxlen) { struct crypt_config *cc = ti->private; unsigned int sz = 0; switch (type) { case STATUSTYPE_INFO: result[0] = '\0'; break; case STATUSTYPE_TABLE: DMEMIT("%s ", cc->cipher_string); if (cc->key_size > 0) { if ((maxlen - sz) < ((cc->key_size << 1) + 1)) return -ENOMEM; crypt_encode_key(result + sz, cc->key, cc->key_size); sz += cc->key_size << 1; } else { if (sz >= maxlen) return -ENOMEM; result[sz++] = '-'; } DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset, cc->dev->name, (unsigned long long)cc->start); if (ti->num_discard_requests) DMEMIT(" 1 allow_discards"); break; } return 0; } 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, 12, 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; _crypt_io_pool = KMEM_CACHE(dm_crypt_io, 0); if (!_crypt_io_pool) return -ENOMEM; r = dm_register_target(&crypt_target); if (r < 0) { DMERR("register failed %d", r); kmem_cache_destroy(_crypt_io_pool); } return r; } static void __exit dm_crypt_exit(void) { dm_unregister_target(&crypt_target); kmem_cache_destroy(_crypt_io_pool); } module_init(dm_crypt_init); module_exit(dm_crypt_exit); MODULE_AUTHOR("Christophe Saout <christophe@saout.de>"); MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption"); MODULE_LICENSE("GPL");