diff options
Diffstat (limited to 'drivers/md/dm-crypt.c')
| -rw-r--r-- | drivers/md/dm-crypt.c | 977 |
1 files changed, 977 insertions, 0 deletions
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c new file mode 100644 index 0000000..77619a5 --- /dev/null +++ b/drivers/md/dm-crypt.c @@ -0,0 +1,977 @@ +/* + * Copyright (C) 2003 Christophe Saout <christophe@saout.de> + * Copyright (C) 2004 Clemens Fruhwirth <clemens@endorphin.org> + * + * This file is released under the GPL. + */ + +#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 <asm/atomic.h> +#include <asm/scatterlist.h> +#include <asm/page.h> + +#include "dm.h" + +#define PFX "crypt: " + +/* + * per bio private data + */ +struct crypt_io { + struct dm_target *target; + struct bio *bio; + struct bio *first_clone; + struct work_struct work; + atomic_t pending; + int error; +}; + +/* + * context holding the current state of a multi-part conversion + */ +struct convert_context { + 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; + int write; +}; + +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. + */ +struct crypt_config { + struct dm_dev *dev; + sector_t start; + + /* + * pool for per bio private data and + * for encryption buffer pages + */ + mempool_t *io_pool; + mempool_t *page_pool; + + /* + * crypto related data + */ + struct crypt_iv_operations *iv_gen_ops; + char *iv_mode; + void *iv_gen_private; + sector_t iv_offset; + unsigned int iv_size; + + struct crypto_tfm *tfm; + unsigned int key_size; + u8 key[0]; +}; + +#define MIN_IOS 256 +#define MIN_POOL_PAGES 32 +#define MIN_BIO_PAGES 8 + +static kmem_cache_t *_crypt_io_pool; + +/* + * Mempool alloc and free functions for the page + */ +static void *mempool_alloc_page(unsigned int __nocast gfp_mask, void *data) +{ + return alloc_page(gfp_mask); +} + +static void mempool_free_page(void *page, void *data) +{ + __free_page(page); +} + + +/* + * Different IV generation algorithms: + * + * plain: the initial vector is the 32-bit low-endian version of the sector + * number, padded with zeros if neccessary. + * + * ess_iv: "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. + * + * 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_tfm *essiv_tfm; + struct crypto_tfm *hash_tfm; + struct scatterlist sg; + unsigned int saltsize; + u8 *salt; + + if (opts == NULL) { + ti->error = PFX "Digest algorithm missing for ESSIV mode"; + return -EINVAL; + } + + /* Hash the cipher key with the given hash algorithm */ + hash_tfm = crypto_alloc_tfm(opts, 0); + if (hash_tfm == NULL) { + ti->error = PFX "Error initializing ESSIV hash"; + return -EINVAL; + } + + if (crypto_tfm_alg_type(hash_tfm) != CRYPTO_ALG_TYPE_DIGEST) { + ti->error = PFX "Expected digest algorithm for ESSIV hash"; + crypto_free_tfm(hash_tfm); + return -EINVAL; + } + + saltsize = crypto_tfm_alg_digestsize(hash_tfm); + salt = kmalloc(saltsize, GFP_KERNEL); + if (salt == NULL) { + ti->error = PFX "Error kmallocing salt storage in ESSIV"; + crypto_free_tfm(hash_tfm); + return -ENOMEM; + } + + sg.page = virt_to_page(cc->key); + sg.offset = offset_in_page(cc->key); + sg.length = cc->key_size; + crypto_digest_digest(hash_tfm, &sg, 1, salt); + crypto_free_tfm(hash_tfm); + + /* Setup the essiv_tfm with the given salt */ + essiv_tfm = crypto_alloc_tfm(crypto_tfm_alg_name(cc->tfm), + CRYPTO_TFM_MODE_ECB); + if (essiv_tfm == NULL) { + ti->error = PFX "Error allocating crypto tfm for ESSIV"; + kfree(salt); + return -EINVAL; + } + if (crypto_tfm_alg_blocksize(essiv_tfm) + != crypto_tfm_alg_ivsize(cc->tfm)) { + ti->error = PFX "Block size of ESSIV cipher does " + "not match IV size of block cipher"; + crypto_free_tfm(essiv_tfm); + kfree(salt); + return -EINVAL; + } + if (crypto_cipher_setkey(essiv_tfm, salt, saltsize) < 0) { + ti->error = PFX "Failed to set key for ESSIV cipher"; + crypto_free_tfm(essiv_tfm); + kfree(salt); + return -EINVAL; + } + kfree(salt); + + cc->iv_gen_private = (void *)essiv_tfm; + return 0; +} + +static void crypt_iv_essiv_dtr(struct crypt_config *cc) +{ + crypto_free_tfm((struct crypto_tfm *)cc->iv_gen_private); + cc->iv_gen_private = NULL; +} + +static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv, sector_t sector) +{ + struct scatterlist sg = { NULL, }; + + memset(iv, 0, cc->iv_size); + *(u64 *)iv = cpu_to_le64(sector); + + sg.page = virt_to_page(iv); + sg.offset = offset_in_page(iv); + sg.length = cc->iv_size; + crypto_cipher_encrypt((struct crypto_tfm *)cc->iv_gen_private, + &sg, &sg, 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 inline int +crypt_convert_scatterlist(struct crypt_config *cc, struct scatterlist *out, + struct scatterlist *in, unsigned int length, + int write, sector_t sector) +{ + u8 iv[cc->iv_size]; + int r; + + if (cc->iv_gen_ops) { + r = cc->iv_gen_ops->generator(cc, iv, sector); + if (r < 0) + return r; + + if (write) + r = crypto_cipher_encrypt_iv(cc->tfm, out, in, length, iv); + else + r = crypto_cipher_decrypt_iv(cc->tfm, out, in, length, iv); + } else { + if (write) + r = crypto_cipher_encrypt(cc->tfm, out, in, length); + else + r = crypto_cipher_decrypt(cc->tfm, out, in, length); + } + + return r; +} + +static void +crypt_convert_init(struct crypt_config *cc, struct convert_context *ctx, + struct bio *bio_out, struct bio *bio_in, + sector_t sector, int write) +{ + 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; + ctx->write = write; +} + +/* + * 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 = 0; + + while(ctx->idx_in < ctx->bio_in->bi_vcnt && + ctx->idx_out < ctx->bio_out->bi_vcnt) { + 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 scatterlist sg_in = { + .page = bv_in->bv_page, + .offset = bv_in->bv_offset + ctx->offset_in, + .length = 1 << SECTOR_SHIFT + }; + struct scatterlist sg_out = { + .page = bv_out->bv_page, + .offset = bv_out->bv_offset + ctx->offset_out, + .length = 1 << SECTOR_SHIFT + }; + + ctx->offset_in += sg_in.length; + if (ctx->offset_in >= bv_in->bv_len) { + ctx->offset_in = 0; + ctx->idx_in++; + } + + ctx->offset_out += sg_out.length; + if (ctx->offset_out >= bv_out->bv_len) { + ctx->offset_out = 0; + ctx->idx_out++; + } + + r = crypt_convert_scatterlist(cc, &sg_out, &sg_in, sg_in.length, + ctx->write, ctx->sector); + if (r < 0) + break; + + ctx->sector++; + } + + return r; +} + +/* + * 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 + */ +static struct bio * +crypt_alloc_buffer(struct crypt_config *cc, unsigned int size, + struct bio *base_bio, unsigned int *bio_vec_idx) +{ + struct bio *bio; + unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; + int gfp_mask = GFP_NOIO | __GFP_HIGHMEM; + unsigned long flags = current->flags; + unsigned int i; + + /* + * Tell VM to act less aggressively and fail earlier. + * This is not necessary but increases throughput. + * FIXME: Is this really intelligent? + */ + current->flags &= ~PF_MEMALLOC; + + if (base_bio) + bio = bio_clone(base_bio, GFP_NOIO); + else + bio = bio_alloc(GFP_NOIO, nr_iovecs); + if (!bio) { + if (flags & PF_MEMALLOC) + current->flags |= PF_MEMALLOC; + return NULL; + } + + /* if the last bio was not complete, continue where that one ended */ + bio->bi_idx = *bio_vec_idx; + bio->bi_vcnt = *bio_vec_idx; + bio->bi_size = 0; + bio->bi_flags &= ~(1 << BIO_SEG_VALID); + + /* bio->bi_idx pages have already been allocated */ + size -= bio->bi_idx * PAGE_SIZE; + + for(i = bio->bi_idx; i < nr_iovecs; i++) { + struct bio_vec *bv = bio_iovec_idx(bio, i); + + bv->bv_page = mempool_alloc(cc->page_pool, gfp_mask); + if (!bv->bv_page) + 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 - bio->bi_idx) == (MIN_BIO_PAGES - 1)) + gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT; + + bv->bv_offset = 0; + if (size > PAGE_SIZE) + bv->bv_len = PAGE_SIZE; + else + bv->bv_len = size; + + bio->bi_size += bv->bv_len; + bio->bi_vcnt++; + size -= bv->bv_len; + } + + if (flags & PF_MEMALLOC) + current->flags |= PF_MEMALLOC; + + if (!bio->bi_size) { + bio_put(bio); + return NULL; + } + + /* + * Remember the last bio_vec allocated to be able + * to correctly continue after the splitting. + */ + *bio_vec_idx = bio->bi_vcnt; + + return bio; +} + +static void crypt_free_buffer_pages(struct crypt_config *cc, + struct bio *bio, unsigned int bytes) +{ + unsigned int i, start, end; + struct bio_vec *bv; + + /* + * This is ugly, but Jens Axboe thinks that using bi_idx in the + * endio function is too dangerous at the moment, so I calculate the + * correct position using bi_vcnt and bi_size. + * The bv_offset and bv_len fields might already be modified but we + * know that we always allocated whole pages. + * A fix to the bi_idx issue in the kernel is in the works, so + * we will hopefully be able to revert to the cleaner solution soon. + */ + i = bio->bi_vcnt - 1; + bv = bio_iovec_idx(bio, i); + end = (i << PAGE_SHIFT) + (bv->bv_offset + bv->bv_len) - bio->bi_size; + start = end - bytes; + + start >>= PAGE_SHIFT; + if (!bio->bi_size) + end = bio->bi_vcnt; + else + end >>= PAGE_SHIFT; + + for(i = start; i < end; i++) { + bv = bio_iovec_idx(bio, i); + BUG_ON(!bv->bv_page); + mempool_free(bv->bv_page, cc->page_pool); + bv->bv_page = NULL; + } +} + +/* + * One of the bios was finished. Check for completion of + * the whole request and correctly clean up the buffer. + */ +static void dec_pending(struct crypt_io *io, int error) +{ + struct crypt_config *cc = (struct crypt_config *) io->target->private; + + if (error < 0) + io->error = error; + + if (!atomic_dec_and_test(&io->pending)) + return; + + if (io->first_clone) + bio_put(io->first_clone); + + bio_endio(io->bio, io->bio->bi_size, io->error); + + mempool_free(io, cc->io_pool); +} + +/* + * kcryptd: + * + * Needed because it would be very unwise to do decryption in an + * interrupt context, so bios returning from read requests get + * queued here. + */ +static struct workqueue_struct *_kcryptd_workqueue; + +static void kcryptd_do_work(void *data) +{ + struct crypt_io *io = (struct crypt_io *) data; + struct crypt_config *cc = (struct crypt_config *) io->target->private; + struct convert_context ctx; + int r; + + crypt_convert_init(cc, &ctx, io->bio, io->bio, + io->bio->bi_sector - io->target->begin, 0); + r = crypt_convert(cc, &ctx); + + dec_pending(io, r); +} + +static void kcryptd_queue_io(struct crypt_io *io) +{ + INIT_WORK(&io->work, kcryptd_do_work, io); + queue_work(_kcryptd_workqueue, &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++; + } +} + +/* + * 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_tfm *tfm; + char *tmp; + char *cipher; + char *chainmode; + char *ivmode; + char *ivopts; + unsigned int crypto_flags; + unsigned int key_size; + + if (argc != 5) { + ti->error = PFX "Not enough arguments"; + return -EINVAL; + } + + tmp = argv[0]; + cipher = strsep(&tmp, "-"); + chainmode = strsep(&tmp, "-"); + ivopts = strsep(&tmp, "-"); + ivmode = strsep(&ivopts, ":"); + + if (tmp) + DMWARN(PFX "Unexpected additional cipher options"); + + key_size = strlen(argv[1]) >> 1; + + cc = kmalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL); + if (cc == NULL) { + ti->error = + PFX "Cannot allocate transparent encryption context"; + return -ENOMEM; + } + + cc->key_size = key_size; + if ((!key_size && strcmp(argv[1], "-") != 0) || + (key_size && crypt_decode_key(cc->key, argv[1], key_size) < 0)) { + ti->error = PFX "Error decoding key"; + goto bad1; + } + + /* Compatiblity mode for old dm-crypt cipher strings */ + if (!chainmode || (strcmp(chainmode, "plain") == 0 && !ivmode)) { + chainmode = "cbc"; + ivmode = "plain"; + } + + /* Choose crypto_flags according to chainmode */ + if (strcmp(chainmode, "cbc") == 0) + crypto_flags = CRYPTO_TFM_MODE_CBC; + else if (strcmp(chainmode, "ecb") == 0) + crypto_flags = CRYPTO_TFM_MODE_ECB; + else { + ti->error = PFX "Unknown chaining mode"; + goto bad1; + } + + if (crypto_flags != CRYPTO_TFM_MODE_ECB && !ivmode) { + ti->error = PFX "This chaining mode requires an IV mechanism"; + goto bad1; + } + + tfm = crypto_alloc_tfm(cipher, crypto_flags); + if (!tfm) { + ti->error = PFX "Error allocating crypto tfm"; + goto bad1; + } + if (crypto_tfm_alg_type(tfm) != CRYPTO_ALG_TYPE_CIPHER) { + ti->error = PFX "Expected cipher algorithm"; + goto bad2; + } + + cc->tfm = tfm; + + /* + * Choose ivmode. Valid modes: "plain", "essiv:<esshash>". + * 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 { + ti->error = PFX "Invalid IV mode"; + goto bad2; + } + + if (cc->iv_gen_ops && cc->iv_gen_ops->ctr && + cc->iv_gen_ops->ctr(cc, ti, ivopts) < 0) + goto bad2; + + if (tfm->crt_cipher.cit_decrypt_iv && tfm->crt_cipher.cit_encrypt_iv) + /* at least a 64 bit sector number should fit in our buffer */ + cc->iv_size = max(crypto_tfm_alg_ivsize(tfm), + (unsigned int)(sizeof(u64) / sizeof(u8))); + else { + cc->iv_size = 0; + if (cc->iv_gen_ops) { + DMWARN(PFX "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(MIN_IOS, mempool_alloc_slab, + mempool_free_slab, _crypt_io_pool); + if (!cc->io_pool) { + ti->error = PFX "Cannot allocate crypt io mempool"; + goto bad3; + } + + cc->page_pool = mempool_create(MIN_POOL_PAGES, mempool_alloc_page, + mempool_free_page, NULL); + if (!cc->page_pool) { + ti->error = PFX "Cannot allocate page mempool"; + goto bad4; + } + + if (tfm->crt_cipher.cit_setkey(tfm, cc->key, key_size) < 0) { + ti->error = PFX "Error setting key"; + goto bad5; + } + + if (sscanf(argv[2], SECTOR_FORMAT, &cc->iv_offset) != 1) { + ti->error = PFX "Invalid iv_offset sector"; + goto bad5; + } + + if (sscanf(argv[4], SECTOR_FORMAT, &cc->start) != 1) { + ti->error = PFX "Invalid device sector"; + goto bad5; + } + + if (dm_get_device(ti, argv[3], cc->start, ti->len, + dm_table_get_mode(ti->table), &cc->dev)) { + ti->error = PFX "Device lookup failed"; + goto bad5; + } + + 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 = PFX "Error kmallocing iv_mode string"; + goto bad5; + } + strcpy(cc->iv_mode, ivmode); + } else + cc->iv_mode = NULL; + + ti->private = cc; + return 0; + +bad5: + mempool_destroy(cc->page_pool); +bad4: + mempool_destroy(cc->io_pool); +bad3: + if (cc->iv_gen_ops && cc->iv_gen_ops->dtr) + cc->iv_gen_ops->dtr(cc); +bad2: + crypto_free_tfm(tfm); +bad1: + kfree(cc); + return -EINVAL; +} + +static void crypt_dtr(struct dm_target *ti) +{ + struct crypt_config *cc = (struct crypt_config *) ti->private; + + mempool_destroy(cc->page_pool); + mempool_destroy(cc->io_pool); + + if (cc->iv_mode) + kfree(cc->iv_mode); + if (cc->iv_gen_ops && cc->iv_gen_ops->dtr) + cc->iv_gen_ops->dtr(cc); + crypto_free_tfm(cc->tfm); + dm_put_device(ti, cc->dev); + kfree(cc); +} + +static int crypt_endio(struct bio *bio, unsigned int done, int error) +{ + struct crypt_io *io = (struct crypt_io *) bio->bi_private; + struct crypt_config *cc = (struct crypt_config *) io->target->private; + + if (bio_data_dir(bio) == WRITE) { + /* + * free the processed pages, even if + * it's only a partially completed write + */ + crypt_free_buffer_pages(cc, bio, done); + } + + if (bio->bi_size) + return 1; + + bio_put(bio); + + /* + * successful reads are decrypted by the worker thread + */ + if ((bio_data_dir(bio) == READ) + && bio_flagged(bio, BIO_UPTODATE)) { + kcryptd_queue_io(io); + return 0; + } + + dec_pending(io, error); + return error; +} + +static inline struct bio * +crypt_clone(struct crypt_config *cc, struct crypt_io *io, struct bio *bio, + sector_t sector, unsigned int *bvec_idx, + struct convert_context *ctx) +{ + struct bio *clone; + + if (bio_data_dir(bio) == WRITE) { + clone = crypt_alloc_buffer(cc, bio->bi_size, + io->first_clone, bvec_idx); + if (clone) { + ctx->bio_out = clone; + if (crypt_convert(cc, ctx) < 0) { + crypt_free_buffer_pages(cc, clone, + clone->bi_size); + bio_put(clone); + return NULL; + } + } + } else { + /* + * 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(GFP_NOIO, bio_segments(bio)); + if (clone) { + clone->bi_idx = 0; + clone->bi_vcnt = bio_segments(bio); + clone->bi_size = bio->bi_size; + memcpy(clone->bi_io_vec, bio_iovec(bio), + sizeof(struct bio_vec) * clone->bi_vcnt); + } + } + + if (!clone) + return NULL; + + clone->bi_private = io; + clone->bi_end_io = crypt_endio; + clone->bi_bdev = cc->dev->bdev; + clone->bi_sector = cc->start + sector; + clone->bi_rw = bio->bi_rw; + + return clone; +} + +static int crypt_map(struct dm_target *ti, struct bio *bio, + union map_info *map_context) +{ + struct crypt_config *cc = (struct crypt_config *) ti->private; + struct crypt_io *io = mempool_alloc(cc->io_pool, GFP_NOIO); + struct convert_context ctx; + struct bio *clone; + unsigned int remaining = bio->bi_size; + sector_t sector = bio->bi_sector - ti->begin; + unsigned int bvec_idx = 0; + + io->target = ti; + io->bio = bio; + io->first_clone = NULL; + io->error = 0; + atomic_set(&io->pending, 1); /* hold a reference */ + + if (bio_data_dir(bio) == WRITE) + crypt_convert_init(cc, &ctx, NULL, bio, sector, 1); + + /* + * 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_clone(cc, io, bio, sector, &bvec_idx, &ctx); + if (!clone) + goto cleanup; + + if (!io->first_clone) { + /* + * hold a reference to the first clone, because it + * holds the bio_vec array and that can't be freed + * before all other clones are released + */ + bio_get(clone); + io->first_clone = clone; + } + atomic_inc(&io->pending); + + remaining -= clone->bi_size; + sector += bio_sectors(clone); + + generic_make_request(clone); + + /* out of memory -> run queues */ + if (remaining) + blk_congestion_wait(bio_data_dir(clone), HZ/100); + } + + /* drop reference, clones could have returned before we reach this */ + dec_pending(io, 0); + return 0; + +cleanup: + if (io->first_clone) { + dec_pending(io, -ENOMEM); + return 0; + } + + /* if no bio has been dispatched yet, we can directly return the error */ + mempool_free(io, cc->io_pool); + return -ENOMEM; +} + +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; + const char *cipher; + const char *chainmode = NULL; + unsigned int sz = 0; + + switch (type) { + case STATUSTYPE_INFO: + result[0] = '\0'; + break; + + case STATUSTYPE_TABLE: + cipher = crypto_tfm_alg_name(cc->tfm); + + switch(cc->tfm->crt_cipher.cit_mode) { + case CRYPTO_TFM_MODE_CBC: + chainmode = "cbc"; + break; + case CRYPTO_TFM_MODE_ECB: + chainmode = "ecb"; + break; + default: + BUG(); + } + + if (cc->iv_mode) + DMEMIT("%s-%s-%s ", cipher, chainmode, cc->iv_mode); + else + DMEMIT("%s-%s ", cipher, 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(" " SECTOR_FORMAT " %s " SECTOR_FORMAT, + cc->iv_offset, cc->dev->name, cc->start); + break; + } + return 0; +} + +static struct target_type crypt_target = { + .name = "crypt", + .version= {1, 1, 0}, + .module = THIS_MODULE, + .ctr = crypt_ctr, + .dtr = crypt_dtr, + .map = crypt_map, + .status = crypt_status, +}; + +static int __init dm_crypt_init(void) +{ + int r; + + _crypt_io_pool = kmem_cache_create("dm-crypt_io", + sizeof(struct crypt_io), + 0, 0, NULL, NULL); + if (!_crypt_io_pool) + return -ENOMEM; + + _kcryptd_workqueue = create_workqueue("kcryptd"); + if (!_kcryptd_workqueue) { + r = -ENOMEM; + DMERR(PFX "couldn't create kcryptd"); + goto bad1; + } + + r = dm_register_target(&crypt_target); + if (r < 0) { + DMERR(PFX "register failed %d", r); + goto bad2; + } + + return 0; + +bad2: + destroy_workqueue(_kcryptd_workqueue); +bad1: + 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(PFX "unregister failed %d", r); + + destroy_workqueue(_kcryptd_workqueue); + 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"); |
