/* * Copyright (C) 2003 Christophe Saout <christophe@saout.de> * Copyright (C) 2004 Clemens Fruhwirth <clemens@endorphin.org> * Copyright (C) 2006-2008 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 <asm/atomic.h> #include <linux/scatterlist.h> #include <asm/page.h> #include <asm/unaligned.h> #include <linux/device-mapper.h> #define DM_MSG_PREFIX "crypt" #define MESG_STR(x) x, sizeof(x) /* * 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 sector; atomic_t pending; }; /* * per bio private data */ struct dm_crypt_io { struct dm_target *target; struct bio *base_bio; struct work_struct work; struct convert_context ctx; atomic_t pending; int error; sector_t sector; struct dm_crypt_io *base_io; }; struct dm_crypt_request { struct scatterlist sg_in; struct scatterlist sg_out; }; 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); const char *(*status)(struct crypt_config *cc); int (*generator)(struct crypt_config *cc, u8 *iv, sector_t sector); }; /* * 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 }; 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; /* * crypto related data */ struct crypt_iv_operations *iv_gen_ops; char *iv_mode; union { struct crypto_cipher *essiv_tfm; int benbi_shift; } iv_gen_private; sector_t iv_offset; unsigned int iv_size; /* * 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; struct ablkcipher_request *req; char cipher[CRYPTO_MAX_ALG_NAME]; char chainmode[CRYPTO_MAX_ALG_NAME]; struct crypto_ablkcipher *tfm; unsigned long flags; unsigned int key_size; u8 key[0]; }; #define MIN_IOS 16 #define MIN_POOL_PAGES 32 #define MIN_BIO_PAGES 8 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); /* * Different IV generation algorithms: * * plain: the initial vector is the 32-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. * * 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, sector_t sector) { memset(iv, 0, cc->iv_size); *(u32 *)iv = cpu_to_le32(sector & 0xffffffff); return 0; } static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti, const char *opts) { struct crypto_cipher *essiv_tfm; struct crypto_hash *hash_tfm; struct hash_desc desc; struct scatterlist sg; unsigned int saltsize; u8 *salt; int err; if (opts == NULL) { ti->error = "Digest algorithm missing for ESSIV mode"; return -EINVAL; } /* Hash the cipher key with the given hash algorithm */ hash_tfm = crypto_alloc_hash(opts, 0, CRYPTO_ALG_ASYNC); if (IS_ERR(hash_tfm)) { ti->error = "Error initializing ESSIV hash"; return PTR_ERR(hash_tfm); } saltsize = crypto_hash_digestsize(hash_tfm); salt = kmalloc(saltsize, GFP_KERNEL); if (salt == NULL) { ti->error = "Error kmallocing salt storage in ESSIV"; crypto_free_hash(hash_tfm); return -ENOMEM; } sg_init_one(&sg, cc->key, cc->key_size); desc.tfm = hash_tfm; desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; err = crypto_hash_digest(&desc, &sg, cc->key_size, salt); crypto_free_hash(hash_tfm); if (err) { ti->error = "Error calculating hash in ESSIV"; kfree(salt); return 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"; kfree(salt); return PTR_ERR(essiv_tfm); } if (crypto_cipher_blocksize(essiv_tfm) != crypto_ablkcipher_ivsize(cc->tfm)) { ti->error = "Block size of ESSIV cipher does " "not match IV size of block cipher"; crypto_free_cipher(essiv_tfm); kfree(salt); return -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); kfree(salt); return err; } kfree(salt); cc->iv_gen_private.essiv_tfm = essiv_tfm; return 0; } static void crypt_iv_essiv_dtr(struct crypt_config *cc) { crypto_free_cipher(cc->iv_gen_private.essiv_tfm); cc->iv_gen_private.essiv_tfm = NULL; } static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv, sector_t sector) { memset(iv, 0, cc->iv_size); *(u64 *)iv = cpu_to_le64(sector); crypto_cipher_encrypt_one(cc->iv_gen_private.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(cc->tfm); 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, sector_t sector) { __be64 val; memset(iv, 0, cc->iv_size - sizeof(u64)); /* rest is cleared below */ val = cpu_to_be64(((u64)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, sector_t sector) { memset(iv, 0, cc->iv_size); return 0; } static struct crypt_iv_operations crypt_iv_plain_ops = { .generator = crypt_iv_plain_gen }; static struct crypt_iv_operations crypt_iv_essiv_ops = { .ctr = crypt_iv_essiv_ctr, .dtr = crypt_iv_essiv_dtr, .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 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->sector = sector + cc->iv_offset; init_completion(&ctx->restart); } 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 = 0; dmreq = (struct dm_crypt_request *)((char *)req + cc->dmreq_start); iv = (u8 *)ALIGN((unsigned long)(dmreq + 1), crypto_ablkcipher_alignmask(cc->tfm) + 1); 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, ctx->sector); 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); 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) { if (!cc->req) cc->req = mempool_alloc(cc->req_pool, GFP_NOIO); ablkcipher_request_set_tfm(cc->req, cc->tfm); ablkcipher_request_set_callback(cc->req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, kcryptd_async_done, ctx); } /* * Encrypt / decrypt data from one bio to another one (can be the same one) */ static int crypt_convert(struct crypt_config *cc, struct convert_context *ctx) { int r; atomic_set(&ctx->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->pending); r = crypt_convert_block(cc, ctx, cc->req); switch (r) { /* async */ case -EBUSY: wait_for_completion(&ctx->restart); INIT_COMPLETION(ctx->restart); /* fall through*/ case -EINPROGRESS: cc->req = NULL; ctx->sector++; continue; /* sync */ case 0: atomic_dec(&ctx->pending); ctx->sector++; cond_resched(); continue; /* error */ default: atomic_dec(&ctx->pending); return r; } } return 0; } static void dm_crypt_bio_destructor(struct bio *bio) { struct dm_crypt_io *io = bio->bi_private; struct crypt_config *cc = io->target->private; bio_free(bio, cc->bs); } /* * 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->target->private; 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 additional bios while submitting this partial bio */ if (i == (MIN_BIO_PAGES - 1)) 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 dm_target *ti, struct bio *bio, sector_t sector) { struct crypt_config *cc = ti->private; struct dm_crypt_io *io; io = mempool_alloc(cc->io_pool, GFP_NOIO); io->target = ti; io->base_bio = bio; io->sector = sector; io->error = 0; io->base_io = NULL; atomic_set(&io->pending, 0); return io; } static void crypt_inc_pending(struct dm_crypt_io *io) { atomic_inc(&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->target->private; if (!atomic_dec_and_test(&io->pending)) return; if (likely(!io->base_io)) bio_endio(io->base_bio, io->error); else { if (io->error && !io->base_io->error) io->base_io->error = io->error; crypt_dec_pending(io->base_io); } mempool_free(io, cc->io_pool); } /* * 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. */ static void crypt_endio(struct bio *clone, int error) { struct dm_crypt_io *io = clone->bi_private; struct crypt_config *cc = io->target->private; 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->target->private; clone->bi_private = io; clone->bi_end_io = crypt_endio; clone->bi_bdev = cc->dev->bdev; clone->bi_rw = io->base_bio->bi_rw; clone->bi_destructor = dm_crypt_bio_destructor; } static void kcryptd_io_read(struct dm_crypt_io *io) { struct crypt_config *cc = io->target->private; struct bio *base_bio = io->base_bio; struct bio *clone; crypt_inc_pending(io); /* * 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_alloc_bioset(GFP_NOIO, bio_segments(base_bio), cc->bs); if (unlikely(!clone)) { io->error = -ENOMEM; crypt_dec_pending(io); return; } clone_init(io, clone); clone->bi_idx = 0; clone->bi_vcnt = bio_segments(base_bio); clone->bi_size = base_bio->bi_size; clone->bi_sector = cc->start + io->sector; memcpy(clone->bi_io_vec, bio_iovec(base_bio), sizeof(struct bio_vec) * clone->bi_vcnt); generic_make_request(clone); } 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) kcryptd_io_read(io); else kcryptd_io_write(io); } static void kcryptd_queue_io(struct dm_crypt_io *io) { struct crypt_config *cc = io->target->private; 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 error, int async) { struct bio *clone = io->ctx.bio_out; struct crypt_config *cc = io->target->private; if (unlikely(error < 0)) { crypt_free_buffer_pages(cc, clone); bio_put(clone); io->error = -EIO; 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->target->private; 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); crypt_finished = atomic_dec_and_test(&io->ctx.pending); /* Encryption was already finished, submit io now */ if (crypt_finished) { kcryptd_crypt_write_io_submit(io, r, 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(WRITE, 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->target, 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, int error) { if (unlikely(error < 0)) io->error = -EIO; crypt_dec_pending(io); } static void kcryptd_crypt_read_convert(struct dm_crypt_io *io) { struct crypt_config *cc = io->target->private; 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 (atomic_dec_and_test(&io->ctx.pending)) kcryptd_crypt_read_done(io, r); crypt_dec_pending(io); } static void kcryptd_async_done(struct crypto_async_request *async_req, int error) { struct convert_context *ctx = async_req->data; struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx); struct crypt_config *cc = io->target->private; if (error == -EINPROGRESS) { complete(&ctx->restart); return; } mempool_free(ablkcipher_request_cast(async_req), cc->req_pool); if (!atomic_dec_and_test(&ctx->pending)) return; if (bio_data_dir(io->base_bio) == READ) kcryptd_crypt_read_done(io, error); else kcryptd_crypt_write_io_submit(io, error, 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->target->private; 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]; char *endp; unsigned int i; buffer[2] = '\0'; for (i = 0; i < size; i++) { buffer[0] = *hex++; buffer[1] = *hex++; key[i] = (u8)simple_strtoul(buffer, &endp, 16); if (endp != &buffer[2]) 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 int crypt_set_key(struct crypt_config *cc, char *key) { unsigned key_size = strlen(key) >> 1; if (cc->key_size && cc->key_size != key_size) return -EINVAL; cc->key_size = key_size; /* initial settings */ if ((!key_size && strcmp(key, "-")) || (key_size && crypt_decode_key(cc->key, key, key_size) < 0)) return -EINVAL; set_bit(DM_CRYPT_KEY_VALID, &cc->flags); return 0; } 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 0; } /* * 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; struct crypto_ablkcipher *tfm; char *tmp; char *cipher; char *chainmode; char *ivmode; char *ivopts; unsigned int key_size; unsigned long long tmpll; if (argc != 5) { ti->error = "Not enough arguments"; return -EINVAL; } tmp = argv[0]; cipher = strsep(&tmp, "-"); chainmode = strsep(&tmp, "-"); ivopts = strsep(&tmp, "-"); ivmode = strsep(&ivopts, ":"); if (tmp) DMWARN("Unexpected additional cipher options"); key_size = strlen(argv[1]) >> 1; cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL); if (cc == NULL) { ti->error = "Cannot allocate transparent encryption context"; return -ENOMEM; } if (crypt_set_key(cc, argv[1])) { ti->error = "Error decoding key"; goto bad_cipher; } /* Compatiblity mode for old dm-crypt cipher strings */ if (!chainmode || (strcmp(chainmode, "plain") == 0 && !ivmode)) { chainmode = "cbc"; ivmode = "plain"; } if (strcmp(chainmode, "ecb") && !ivmode) { ti->error = "This chaining mode requires an IV mechanism"; goto bad_cipher; } if (snprintf(cc->cipher, CRYPTO_MAX_ALG_NAME, "%s(%s)", chainmode, cipher) >= CRYPTO_MAX_ALG_NAME) { ti->error = "Chain mode + cipher name is too long"; goto bad_cipher; } tfm = crypto_alloc_ablkcipher(cc->cipher, 0, 0); if (IS_ERR(tfm)) { ti->error = "Error allocating crypto tfm"; goto bad_cipher; } strcpy(cc->cipher, cipher); strcpy(cc->chainmode, chainmode); cc->tfm = tfm; /* * Choose ivmode. Valid modes: "plain", "essiv:<esshash>", "benbi". * 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, "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 { ti->error = "Invalid IV mode"; goto bad_ivmode; } if (cc->iv_gen_ops && cc->iv_gen_ops->ctr && cc->iv_gen_ops->ctr(cc, ti, ivopts) < 0) goto bad_ivmode; cc->iv_size = crypto_ablkcipher_ivsize(tfm); 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 (cc->iv_gen_ops) { DMWARN("Selected cipher does not support IVs"); if (cc->iv_gen_ops->dtr) cc->iv_gen_ops->dtr(cc); cc->iv_gen_ops = NULL; } } 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_slab_pool; } cc->dmreq_start = sizeof(struct ablkcipher_request); cc->dmreq_start += crypto_ablkcipher_reqsize(tfm); cc->dmreq_start = ALIGN(cc->dmreq_start, crypto_tfm_ctx_alignment()); cc->dmreq_start += crypto_ablkcipher_alignmask(tfm) & ~(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_req_pool; } cc->req = NULL; cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0); if (!cc->page_pool) { ti->error = "Cannot allocate page mempool"; goto bad_page_pool; } cc->bs = bioset_create(MIN_IOS, MIN_IOS); if (!cc->bs) { ti->error = "Cannot allocate crypt bioset"; goto bad_bs; } if (crypto_ablkcipher_setkey(tfm, cc->key, key_size) < 0) { ti->error = "Error setting key"; goto bad_device; } if (sscanf(argv[2], "%llu", &tmpll) != 1) { ti->error = "Invalid iv_offset sector"; goto bad_device; } cc->iv_offset = tmpll; if (sscanf(argv[4], "%llu", &tmpll) != 1) { ti->error = "Invalid device sector"; goto bad_device; } cc->start = tmpll; if (dm_get_device(ti, argv[3], cc->start, ti->len, dm_table_get_mode(ti->table), &cc->dev)) { ti->error = "Device lookup failed"; goto bad_device; } if (ivmode && cc->iv_gen_ops) { if (ivopts) *(ivopts - 1) = ':'; cc->iv_mode = kmalloc(strlen(ivmode) + 1, GFP_KERNEL); if (!cc->iv_mode) { ti->error = "Error kmallocing iv_mode string"; goto bad_ivmode_string; } strcpy(cc->iv_mode, ivmode); } else cc->iv_mode = NULL; cc->io_queue = create_singlethread_workqueue("kcryptd_io"); if (!cc->io_queue) { ti->error = "Couldn't create kcryptd io queue"; goto bad_io_queue; } cc->crypt_queue = create_singlethread_workqueue("kcryptd"); if (!cc->crypt_queue) { ti->error = "Couldn't create kcryptd queue"; goto bad_crypt_queue; } ti->private = cc; return 0; bad_crypt_queue: destroy_workqueue(cc->io_queue); bad_io_queue: kfree(cc->iv_mode); bad_ivmode_string: dm_put_device(ti, cc->dev); bad_device: bioset_free(cc->bs); bad_bs: mempool_destroy(cc->page_pool); bad_page_pool: mempool_destroy(cc->req_pool); bad_req_pool: mempool_destroy(cc->io_pool); bad_slab_pool: if (cc->iv_gen_ops && cc->iv_gen_ops->dtr) cc->iv_gen_ops->dtr(cc); bad_ivmode: crypto_free_ablkcipher(tfm); bad_cipher: /* Must zero key material before freeing */ memset(cc, 0, sizeof(*cc) + cc->key_size * sizeof(u8)); kfree(cc); return -EINVAL; } static void crypt_dtr(struct dm_target *ti) { struct crypt_config *cc = (struct crypt_config *) ti->private; destroy_workqueue(cc->io_queue); destroy_workqueue(cc->crypt_queue); if (cc->req) mempool_free(cc->req, cc->req_pool); bioset_free(cc->bs); mempool_destroy(cc->page_pool); mempool_destroy(cc->req_pool); mempool_destroy(cc->io_pool); kfree(cc->iv_mode); if (cc->iv_gen_ops && cc->iv_gen_ops->dtr) cc->iv_gen_ops->dtr(cc); crypto_free_ablkcipher(cc->tfm); dm_put_device(ti, cc->dev); /* Must zero key material before freeing */ memset(cc, 0, sizeof(*cc) + cc->key_size * sizeof(u8)); kfree(cc); } static int crypt_map(struct dm_target *ti, struct bio *bio, union map_info *map_context) { struct dm_crypt_io *io; io = crypt_io_alloc(ti, bio, bio->bi_sector - ti->begin); if (bio_data_dir(io->base_bio) == READ) 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, char *result, unsigned int maxlen) { struct crypt_config *cc = (struct crypt_config *) ti->private; unsigned int sz = 0; switch (type) { case STATUSTYPE_INFO: result[0] = '\0'; break; case STATUSTYPE_TABLE: if (cc->iv_mode) DMEMIT("%s-%s-%s ", cc->cipher, cc->chainmode, cc->iv_mode); else DMEMIT("%s-%s ", cc->cipher, cc->chainmode); 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); 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; if (argc < 2) goto error; if (!strnicmp(argv[0], MESG_STR("key"))) { if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) { DMWARN("not suspended during key manipulation."); return -EINVAL; } if (argc == 3 && !strnicmp(argv[1], MESG_STR("set"))) return crypt_set_key(cc, argv[2]); if (argc == 2 && !strnicmp(argv[1], MESG_STR("wipe"))) 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 + bvm->bi_sector - ti->begin; return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); } static struct target_type crypt_target = { .name = "crypt", .version= {1, 6, 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, }; 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) { int r = dm_unregister_target(&crypt_target); if (r < 0) DMERR("unregister failed %d", r); 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");