diff options
Diffstat (limited to 'kernel/drivers/md/dm-verity.c')
| -rw-r--r-- | kernel/drivers/md/dm-verity.c | 1026 |
1 files changed, 1026 insertions, 0 deletions
diff --git a/kernel/drivers/md/dm-verity.c b/kernel/drivers/md/dm-verity.c new file mode 100644 index 000000000..66616db33 --- /dev/null +++ b/kernel/drivers/md/dm-verity.c @@ -0,0 +1,1026 @@ +/* + * Copyright (C) 2012 Red Hat, Inc. + * + * Author: Mikulas Patocka <mpatocka@redhat.com> + * + * Based on Chromium dm-verity driver (C) 2011 The Chromium OS Authors + * + * This file is released under the GPLv2. + * + * In the file "/sys/module/dm_verity/parameters/prefetch_cluster" you can set + * default prefetch value. Data are read in "prefetch_cluster" chunks from the + * hash device. Setting this greatly improves performance when data and hash + * are on the same disk on different partitions on devices with poor random + * access behavior. + */ + +#include "dm-bufio.h" + +#include <linux/module.h> +#include <linux/device-mapper.h> +#include <linux/reboot.h> +#include <crypto/hash.h> + +#define DM_MSG_PREFIX "verity" + +#define DM_VERITY_ENV_LENGTH 42 +#define DM_VERITY_ENV_VAR_NAME "DM_VERITY_ERR_BLOCK_NR" + +#define DM_VERITY_IO_VEC_INLINE 16 +#define DM_VERITY_MEMPOOL_SIZE 4 +#define DM_VERITY_DEFAULT_PREFETCH_SIZE 262144 + +#define DM_VERITY_MAX_LEVELS 63 +#define DM_VERITY_MAX_CORRUPTED_ERRS 100 + +#define DM_VERITY_OPT_LOGGING "ignore_corruption" +#define DM_VERITY_OPT_RESTART "restart_on_corruption" + +static unsigned dm_verity_prefetch_cluster = DM_VERITY_DEFAULT_PREFETCH_SIZE; + +module_param_named(prefetch_cluster, dm_verity_prefetch_cluster, uint, S_IRUGO | S_IWUSR); + +enum verity_mode { + DM_VERITY_MODE_EIO, + DM_VERITY_MODE_LOGGING, + DM_VERITY_MODE_RESTART +}; + +enum verity_block_type { + DM_VERITY_BLOCK_TYPE_DATA, + DM_VERITY_BLOCK_TYPE_METADATA +}; + +struct dm_verity { + struct dm_dev *data_dev; + struct dm_dev *hash_dev; + struct dm_target *ti; + struct dm_bufio_client *bufio; + char *alg_name; + struct crypto_shash *tfm; + u8 *root_digest; /* digest of the root block */ + u8 *salt; /* salt: its size is salt_size */ + unsigned salt_size; + sector_t data_start; /* data offset in 512-byte sectors */ + sector_t hash_start; /* hash start in blocks */ + sector_t data_blocks; /* the number of data blocks */ + sector_t hash_blocks; /* the number of hash blocks */ + unsigned char data_dev_block_bits; /* log2(data blocksize) */ + unsigned char hash_dev_block_bits; /* log2(hash blocksize) */ + unsigned char hash_per_block_bits; /* log2(hashes in hash block) */ + unsigned char levels; /* the number of tree levels */ + unsigned char version; + unsigned digest_size; /* digest size for the current hash algorithm */ + unsigned shash_descsize;/* the size of temporary space for crypto */ + int hash_failed; /* set to 1 if hash of any block failed */ + enum verity_mode mode; /* mode for handling verification errors */ + unsigned corrupted_errs;/* Number of errors for corrupted blocks */ + + mempool_t *vec_mempool; /* mempool of bio vector */ + + struct workqueue_struct *verify_wq; + + /* starting blocks for each tree level. 0 is the lowest level. */ + sector_t hash_level_block[DM_VERITY_MAX_LEVELS]; +}; + +struct dm_verity_io { + struct dm_verity *v; + + /* original values of bio->bi_end_io and bio->bi_private */ + bio_end_io_t *orig_bi_end_io; + void *orig_bi_private; + + sector_t block; + unsigned n_blocks; + + struct bvec_iter iter; + + struct work_struct work; + + /* + * Three variably-size fields follow this struct: + * + * u8 hash_desc[v->shash_descsize]; + * u8 real_digest[v->digest_size]; + * u8 want_digest[v->digest_size]; + * + * To access them use: io_hash_desc(), io_real_digest() and io_want_digest(). + */ +}; + +struct dm_verity_prefetch_work { + struct work_struct work; + struct dm_verity *v; + sector_t block; + unsigned n_blocks; +}; + +static struct shash_desc *io_hash_desc(struct dm_verity *v, struct dm_verity_io *io) +{ + return (struct shash_desc *)(io + 1); +} + +static u8 *io_real_digest(struct dm_verity *v, struct dm_verity_io *io) +{ + return (u8 *)(io + 1) + v->shash_descsize; +} + +static u8 *io_want_digest(struct dm_verity *v, struct dm_verity_io *io) +{ + return (u8 *)(io + 1) + v->shash_descsize + v->digest_size; +} + +/* + * Auxiliary structure appended to each dm-bufio buffer. If the value + * hash_verified is nonzero, hash of the block has been verified. + * + * The variable hash_verified is set to 0 when allocating the buffer, then + * it can be changed to 1 and it is never reset to 0 again. + * + * There is no lock around this value, a race condition can at worst cause + * that multiple processes verify the hash of the same buffer simultaneously + * and write 1 to hash_verified simultaneously. + * This condition is harmless, so we don't need locking. + */ +struct buffer_aux { + int hash_verified; +}; + +/* + * Initialize struct buffer_aux for a freshly created buffer. + */ +static void dm_bufio_alloc_callback(struct dm_buffer *buf) +{ + struct buffer_aux *aux = dm_bufio_get_aux_data(buf); + + aux->hash_verified = 0; +} + +/* + * Translate input sector number to the sector number on the target device. + */ +static sector_t verity_map_sector(struct dm_verity *v, sector_t bi_sector) +{ + return v->data_start + dm_target_offset(v->ti, bi_sector); +} + +/* + * Return hash position of a specified block at a specified tree level + * (0 is the lowest level). + * The lowest "hash_per_block_bits"-bits of the result denote hash position + * inside a hash block. The remaining bits denote location of the hash block. + */ +static sector_t verity_position_at_level(struct dm_verity *v, sector_t block, + int level) +{ + return block >> (level * v->hash_per_block_bits); +} + +static void verity_hash_at_level(struct dm_verity *v, sector_t block, int level, + sector_t *hash_block, unsigned *offset) +{ + sector_t position = verity_position_at_level(v, block, level); + unsigned idx; + + *hash_block = v->hash_level_block[level] + (position >> v->hash_per_block_bits); + + if (!offset) + return; + + idx = position & ((1 << v->hash_per_block_bits) - 1); + if (!v->version) + *offset = idx * v->digest_size; + else + *offset = idx << (v->hash_dev_block_bits - v->hash_per_block_bits); +} + +/* + * Handle verification errors. + */ +static int verity_handle_err(struct dm_verity *v, enum verity_block_type type, + unsigned long long block) +{ + char verity_env[DM_VERITY_ENV_LENGTH]; + char *envp[] = { verity_env, NULL }; + const char *type_str = ""; + struct mapped_device *md = dm_table_get_md(v->ti->table); + + /* Corruption should be visible in device status in all modes */ + v->hash_failed = 1; + + if (v->corrupted_errs >= DM_VERITY_MAX_CORRUPTED_ERRS) + goto out; + + v->corrupted_errs++; + + switch (type) { + case DM_VERITY_BLOCK_TYPE_DATA: + type_str = "data"; + break; + case DM_VERITY_BLOCK_TYPE_METADATA: + type_str = "metadata"; + break; + default: + BUG(); + } + + DMERR("%s: %s block %llu is corrupted", v->data_dev->name, type_str, + block); + + if (v->corrupted_errs == DM_VERITY_MAX_CORRUPTED_ERRS) + DMERR("%s: reached maximum errors", v->data_dev->name); + + snprintf(verity_env, DM_VERITY_ENV_LENGTH, "%s=%d,%llu", + DM_VERITY_ENV_VAR_NAME, type, block); + + kobject_uevent_env(&disk_to_dev(dm_disk(md))->kobj, KOBJ_CHANGE, envp); + +out: + if (v->mode == DM_VERITY_MODE_LOGGING) + return 0; + + if (v->mode == DM_VERITY_MODE_RESTART) + kernel_restart("dm-verity device corrupted"); + + return 1; +} + +/* + * Verify hash of a metadata block pertaining to the specified data block + * ("block" argument) at a specified level ("level" argument). + * + * On successful return, io_want_digest(v, io) contains the hash value for + * a lower tree level or for the data block (if we're at the lowest leve). + * + * If "skip_unverified" is true, unverified buffer is skipped and 1 is returned. + * If "skip_unverified" is false, unverified buffer is hashed and verified + * against current value of io_want_digest(v, io). + */ +static int verity_verify_level(struct dm_verity_io *io, sector_t block, + int level, bool skip_unverified) +{ + struct dm_verity *v = io->v; + struct dm_buffer *buf; + struct buffer_aux *aux; + u8 *data; + int r; + sector_t hash_block; + unsigned offset; + + verity_hash_at_level(v, block, level, &hash_block, &offset); + + data = dm_bufio_read(v->bufio, hash_block, &buf); + if (unlikely(IS_ERR(data))) + return PTR_ERR(data); + + aux = dm_bufio_get_aux_data(buf); + + if (!aux->hash_verified) { + struct shash_desc *desc; + u8 *result; + + if (skip_unverified) { + r = 1; + goto release_ret_r; + } + + desc = io_hash_desc(v, io); + desc->tfm = v->tfm; + desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; + r = crypto_shash_init(desc); + if (r < 0) { + DMERR("crypto_shash_init failed: %d", r); + goto release_ret_r; + } + + if (likely(v->version >= 1)) { + r = crypto_shash_update(desc, v->salt, v->salt_size); + if (r < 0) { + DMERR("crypto_shash_update failed: %d", r); + goto release_ret_r; + } + } + + r = crypto_shash_update(desc, data, 1 << v->hash_dev_block_bits); + if (r < 0) { + DMERR("crypto_shash_update failed: %d", r); + goto release_ret_r; + } + + if (!v->version) { + r = crypto_shash_update(desc, v->salt, v->salt_size); + if (r < 0) { + DMERR("crypto_shash_update failed: %d", r); + goto release_ret_r; + } + } + + result = io_real_digest(v, io); + r = crypto_shash_final(desc, result); + if (r < 0) { + DMERR("crypto_shash_final failed: %d", r); + goto release_ret_r; + } + if (unlikely(memcmp(result, io_want_digest(v, io), v->digest_size))) { + if (verity_handle_err(v, DM_VERITY_BLOCK_TYPE_METADATA, + hash_block)) { + r = -EIO; + goto release_ret_r; + } + } else + aux->hash_verified = 1; + } + + data += offset; + + memcpy(io_want_digest(v, io), data, v->digest_size); + + dm_bufio_release(buf); + return 0; + +release_ret_r: + dm_bufio_release(buf); + + return r; +} + +/* + * Verify one "dm_verity_io" structure. + */ +static int verity_verify_io(struct dm_verity_io *io) +{ + struct dm_verity *v = io->v; + struct bio *bio = dm_bio_from_per_bio_data(io, + v->ti->per_bio_data_size); + unsigned b; + int i; + + for (b = 0; b < io->n_blocks; b++) { + struct shash_desc *desc; + u8 *result; + int r; + unsigned todo; + + if (likely(v->levels)) { + /* + * First, we try to get the requested hash for + * the current block. If the hash block itself is + * verified, zero is returned. If it isn't, this + * function returns 0 and we fall back to whole + * chain verification. + */ + int r = verity_verify_level(io, io->block + b, 0, true); + if (likely(!r)) + goto test_block_hash; + if (r < 0) + return r; + } + + memcpy(io_want_digest(v, io), v->root_digest, v->digest_size); + + for (i = v->levels - 1; i >= 0; i--) { + int r = verity_verify_level(io, io->block + b, i, false); + if (unlikely(r)) + return r; + } + +test_block_hash: + desc = io_hash_desc(v, io); + desc->tfm = v->tfm; + desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; + r = crypto_shash_init(desc); + if (r < 0) { + DMERR("crypto_shash_init failed: %d", r); + return r; + } + + if (likely(v->version >= 1)) { + r = crypto_shash_update(desc, v->salt, v->salt_size); + if (r < 0) { + DMERR("crypto_shash_update failed: %d", r); + return r; + } + } + todo = 1 << v->data_dev_block_bits; + do { + u8 *page; + unsigned len; + struct bio_vec bv = bio_iter_iovec(bio, io->iter); + + page = kmap_atomic(bv.bv_page); + len = bv.bv_len; + if (likely(len >= todo)) + len = todo; + r = crypto_shash_update(desc, page + bv.bv_offset, len); + kunmap_atomic(page); + + if (r < 0) { + DMERR("crypto_shash_update failed: %d", r); + return r; + } + + bio_advance_iter(bio, &io->iter, len); + todo -= len; + } while (todo); + + if (!v->version) { + r = crypto_shash_update(desc, v->salt, v->salt_size); + if (r < 0) { + DMERR("crypto_shash_update failed: %d", r); + return r; + } + } + + result = io_real_digest(v, io); + r = crypto_shash_final(desc, result); + if (r < 0) { + DMERR("crypto_shash_final failed: %d", r); + return r; + } + if (unlikely(memcmp(result, io_want_digest(v, io), v->digest_size))) { + if (verity_handle_err(v, DM_VERITY_BLOCK_TYPE_DATA, + io->block + b)) + return -EIO; + } + } + + return 0; +} + +/* + * End one "io" structure with a given error. + */ +static void verity_finish_io(struct dm_verity_io *io, int error) +{ + struct dm_verity *v = io->v; + struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_bio_data_size); + + bio->bi_end_io = io->orig_bi_end_io; + bio->bi_private = io->orig_bi_private; + + bio_endio_nodec(bio, error); +} + +static void verity_work(struct work_struct *w) +{ + struct dm_verity_io *io = container_of(w, struct dm_verity_io, work); + + verity_finish_io(io, verity_verify_io(io)); +} + +static void verity_end_io(struct bio *bio, int error) +{ + struct dm_verity_io *io = bio->bi_private; + + if (error) { + verity_finish_io(io, error); + return; + } + + INIT_WORK(&io->work, verity_work); + queue_work(io->v->verify_wq, &io->work); +} + +/* + * Prefetch buffers for the specified io. + * The root buffer is not prefetched, it is assumed that it will be cached + * all the time. + */ +static void verity_prefetch_io(struct work_struct *work) +{ + struct dm_verity_prefetch_work *pw = + container_of(work, struct dm_verity_prefetch_work, work); + struct dm_verity *v = pw->v; + int i; + + for (i = v->levels - 2; i >= 0; i--) { + sector_t hash_block_start; + sector_t hash_block_end; + verity_hash_at_level(v, pw->block, i, &hash_block_start, NULL); + verity_hash_at_level(v, pw->block + pw->n_blocks - 1, i, &hash_block_end, NULL); + if (!i) { + unsigned cluster = ACCESS_ONCE(dm_verity_prefetch_cluster); + + cluster >>= v->data_dev_block_bits; + if (unlikely(!cluster)) + goto no_prefetch_cluster; + + if (unlikely(cluster & (cluster - 1))) + cluster = 1 << __fls(cluster); + + hash_block_start &= ~(sector_t)(cluster - 1); + hash_block_end |= cluster - 1; + if (unlikely(hash_block_end >= v->hash_blocks)) + hash_block_end = v->hash_blocks - 1; + } +no_prefetch_cluster: + dm_bufio_prefetch(v->bufio, hash_block_start, + hash_block_end - hash_block_start + 1); + } + + kfree(pw); +} + +static void verity_submit_prefetch(struct dm_verity *v, struct dm_verity_io *io) +{ + struct dm_verity_prefetch_work *pw; + + pw = kmalloc(sizeof(struct dm_verity_prefetch_work), + GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN); + + if (!pw) + return; + + INIT_WORK(&pw->work, verity_prefetch_io); + pw->v = v; + pw->block = io->block; + pw->n_blocks = io->n_blocks; + queue_work(v->verify_wq, &pw->work); +} + +/* + * Bio map function. It allocates dm_verity_io structure and bio vector and + * fills them. Then it issues prefetches and the I/O. + */ +static int verity_map(struct dm_target *ti, struct bio *bio) +{ + struct dm_verity *v = ti->private; + struct dm_verity_io *io; + + bio->bi_bdev = v->data_dev->bdev; + bio->bi_iter.bi_sector = verity_map_sector(v, bio->bi_iter.bi_sector); + + if (((unsigned)bio->bi_iter.bi_sector | bio_sectors(bio)) & + ((1 << (v->data_dev_block_bits - SECTOR_SHIFT)) - 1)) { + DMERR_LIMIT("unaligned io"); + return -EIO; + } + + if (bio_end_sector(bio) >> + (v->data_dev_block_bits - SECTOR_SHIFT) > v->data_blocks) { + DMERR_LIMIT("io out of range"); + return -EIO; + } + + if (bio_data_dir(bio) == WRITE) + return -EIO; + + io = dm_per_bio_data(bio, ti->per_bio_data_size); + io->v = v; + io->orig_bi_end_io = bio->bi_end_io; + io->orig_bi_private = bio->bi_private; + io->block = bio->bi_iter.bi_sector >> (v->data_dev_block_bits - SECTOR_SHIFT); + io->n_blocks = bio->bi_iter.bi_size >> v->data_dev_block_bits; + + bio->bi_end_io = verity_end_io; + bio->bi_private = io; + io->iter = bio->bi_iter; + + verity_submit_prefetch(v, io); + + generic_make_request(bio); + + return DM_MAPIO_SUBMITTED; +} + +/* + * Status: V (valid) or C (corruption found) + */ +static void verity_status(struct dm_target *ti, status_type_t type, + unsigned status_flags, char *result, unsigned maxlen) +{ + struct dm_verity *v = ti->private; + unsigned sz = 0; + unsigned x; + + switch (type) { + case STATUSTYPE_INFO: + DMEMIT("%c", v->hash_failed ? 'C' : 'V'); + break; + case STATUSTYPE_TABLE: + DMEMIT("%u %s %s %u %u %llu %llu %s ", + v->version, + v->data_dev->name, + v->hash_dev->name, + 1 << v->data_dev_block_bits, + 1 << v->hash_dev_block_bits, + (unsigned long long)v->data_blocks, + (unsigned long long)v->hash_start, + v->alg_name + ); + for (x = 0; x < v->digest_size; x++) + DMEMIT("%02x", v->root_digest[x]); + DMEMIT(" "); + if (!v->salt_size) + DMEMIT("-"); + else + for (x = 0; x < v->salt_size; x++) + DMEMIT("%02x", v->salt[x]); + if (v->mode != DM_VERITY_MODE_EIO) { + DMEMIT(" 1 "); + switch (v->mode) { + case DM_VERITY_MODE_LOGGING: + DMEMIT(DM_VERITY_OPT_LOGGING); + break; + case DM_VERITY_MODE_RESTART: + DMEMIT(DM_VERITY_OPT_RESTART); + break; + default: + BUG(); + } + } + break; + } +} + +static int verity_ioctl(struct dm_target *ti, unsigned cmd, + unsigned long arg) +{ + struct dm_verity *v = ti->private; + int r = 0; + + if (v->data_start || + ti->len != i_size_read(v->data_dev->bdev->bd_inode) >> SECTOR_SHIFT) + r = scsi_verify_blk_ioctl(NULL, cmd); + + return r ? : __blkdev_driver_ioctl(v->data_dev->bdev, v->data_dev->mode, + cmd, arg); +} + +static int verity_merge(struct dm_target *ti, struct bvec_merge_data *bvm, + struct bio_vec *biovec, int max_size) +{ + struct dm_verity *v = ti->private; + struct request_queue *q = bdev_get_queue(v->data_dev->bdev); + + if (!q->merge_bvec_fn) + return max_size; + + bvm->bi_bdev = v->data_dev->bdev; + bvm->bi_sector = verity_map_sector(v, bvm->bi_sector); + + return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); +} + +static int verity_iterate_devices(struct dm_target *ti, + iterate_devices_callout_fn fn, void *data) +{ + struct dm_verity *v = ti->private; + + return fn(ti, v->data_dev, v->data_start, ti->len, data); +} + +static void verity_io_hints(struct dm_target *ti, struct queue_limits *limits) +{ + struct dm_verity *v = ti->private; + + if (limits->logical_block_size < 1 << v->data_dev_block_bits) + limits->logical_block_size = 1 << v->data_dev_block_bits; + + if (limits->physical_block_size < 1 << v->data_dev_block_bits) + limits->physical_block_size = 1 << v->data_dev_block_bits; + + blk_limits_io_min(limits, limits->logical_block_size); +} + +static void verity_dtr(struct dm_target *ti) +{ + struct dm_verity *v = ti->private; + + if (v->verify_wq) + destroy_workqueue(v->verify_wq); + + if (v->vec_mempool) + mempool_destroy(v->vec_mempool); + + if (v->bufio) + dm_bufio_client_destroy(v->bufio); + + kfree(v->salt); + kfree(v->root_digest); + + if (v->tfm) + crypto_free_shash(v->tfm); + + kfree(v->alg_name); + + if (v->hash_dev) + dm_put_device(ti, v->hash_dev); + + if (v->data_dev) + dm_put_device(ti, v->data_dev); + + kfree(v); +} + +/* + * Target parameters: + * <version> The current format is version 1. + * Vsn 0 is compatible with original Chromium OS releases. + * <data device> + * <hash device> + * <data block size> + * <hash block size> + * <the number of data blocks> + * <hash start block> + * <algorithm> + * <digest> + * <salt> Hex string or "-" if no salt. + */ +static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv) +{ + struct dm_verity *v; + struct dm_arg_set as; + const char *opt_string; + unsigned int num, opt_params; + unsigned long long num_ll; + int r; + int i; + sector_t hash_position; + char dummy; + + static struct dm_arg _args[] = { + {0, 1, "Invalid number of feature args"}, + }; + + v = kzalloc(sizeof(struct dm_verity), GFP_KERNEL); + if (!v) { + ti->error = "Cannot allocate verity structure"; + return -ENOMEM; + } + ti->private = v; + v->ti = ti; + + if ((dm_table_get_mode(ti->table) & ~FMODE_READ)) { + ti->error = "Device must be readonly"; + r = -EINVAL; + goto bad; + } + + if (argc < 10) { + ti->error = "Not enough arguments"; + r = -EINVAL; + goto bad; + } + + if (sscanf(argv[0], "%u%c", &num, &dummy) != 1 || + num > 1) { + ti->error = "Invalid version"; + r = -EINVAL; + goto bad; + } + v->version = num; + + r = dm_get_device(ti, argv[1], FMODE_READ, &v->data_dev); + if (r) { + ti->error = "Data device lookup failed"; + goto bad; + } + + r = dm_get_device(ti, argv[2], FMODE_READ, &v->hash_dev); + if (r) { + ti->error = "Data device lookup failed"; + goto bad; + } + + if (sscanf(argv[3], "%u%c", &num, &dummy) != 1 || + !num || (num & (num - 1)) || + num < bdev_logical_block_size(v->data_dev->bdev) || + num > PAGE_SIZE) { + ti->error = "Invalid data device block size"; + r = -EINVAL; + goto bad; + } + v->data_dev_block_bits = __ffs(num); + + if (sscanf(argv[4], "%u%c", &num, &dummy) != 1 || + !num || (num & (num - 1)) || + num < bdev_logical_block_size(v->hash_dev->bdev) || + num > INT_MAX) { + ti->error = "Invalid hash device block size"; + r = -EINVAL; + goto bad; + } + v->hash_dev_block_bits = __ffs(num); + + if (sscanf(argv[5], "%llu%c", &num_ll, &dummy) != 1 || + (sector_t)(num_ll << (v->data_dev_block_bits - SECTOR_SHIFT)) + >> (v->data_dev_block_bits - SECTOR_SHIFT) != num_ll) { + ti->error = "Invalid data blocks"; + r = -EINVAL; + goto bad; + } + v->data_blocks = num_ll; + + if (ti->len > (v->data_blocks << (v->data_dev_block_bits - SECTOR_SHIFT))) { + ti->error = "Data device is too small"; + r = -EINVAL; + goto bad; + } + + if (sscanf(argv[6], "%llu%c", &num_ll, &dummy) != 1 || + (sector_t)(num_ll << (v->hash_dev_block_bits - SECTOR_SHIFT)) + >> (v->hash_dev_block_bits - SECTOR_SHIFT) != num_ll) { + ti->error = "Invalid hash start"; + r = -EINVAL; + goto bad; + } + v->hash_start = num_ll; + + v->alg_name = kstrdup(argv[7], GFP_KERNEL); + if (!v->alg_name) { + ti->error = "Cannot allocate algorithm name"; + r = -ENOMEM; + goto bad; + } + + v->tfm = crypto_alloc_shash(v->alg_name, 0, 0); + if (IS_ERR(v->tfm)) { + ti->error = "Cannot initialize hash function"; + r = PTR_ERR(v->tfm); + v->tfm = NULL; + goto bad; + } + v->digest_size = crypto_shash_digestsize(v->tfm); + if ((1 << v->hash_dev_block_bits) < v->digest_size * 2) { + ti->error = "Digest size too big"; + r = -EINVAL; + goto bad; + } + v->shash_descsize = + sizeof(struct shash_desc) + crypto_shash_descsize(v->tfm); + + v->root_digest = kmalloc(v->digest_size, GFP_KERNEL); + if (!v->root_digest) { + ti->error = "Cannot allocate root digest"; + r = -ENOMEM; + goto bad; + } + if (strlen(argv[8]) != v->digest_size * 2 || + hex2bin(v->root_digest, argv[8], v->digest_size)) { + ti->error = "Invalid root digest"; + r = -EINVAL; + goto bad; + } + + if (strcmp(argv[9], "-")) { + v->salt_size = strlen(argv[9]) / 2; + v->salt = kmalloc(v->salt_size, GFP_KERNEL); + if (!v->salt) { + ti->error = "Cannot allocate salt"; + r = -ENOMEM; + goto bad; + } + if (strlen(argv[9]) != v->salt_size * 2 || + hex2bin(v->salt, argv[9], v->salt_size)) { + ti->error = "Invalid salt"; + r = -EINVAL; + goto bad; + } + } + + argv += 10; + argc -= 10; + + /* Optional parameters */ + if (argc) { + as.argc = argc; + as.argv = argv; + + r = dm_read_arg_group(_args, &as, &opt_params, &ti->error); + if (r) + goto bad; + + while (opt_params) { + opt_params--; + opt_string = dm_shift_arg(&as); + if (!opt_string) { + ti->error = "Not enough feature arguments"; + r = -EINVAL; + goto bad; + } + + if (!strcasecmp(opt_string, DM_VERITY_OPT_LOGGING)) + v->mode = DM_VERITY_MODE_LOGGING; + else if (!strcasecmp(opt_string, DM_VERITY_OPT_RESTART)) + v->mode = DM_VERITY_MODE_RESTART; + else { + ti->error = "Invalid feature arguments"; + r = -EINVAL; + goto bad; + } + } + } + + v->hash_per_block_bits = + __fls((1 << v->hash_dev_block_bits) / v->digest_size); + + v->levels = 0; + if (v->data_blocks) + while (v->hash_per_block_bits * v->levels < 64 && + (unsigned long long)(v->data_blocks - 1) >> + (v->hash_per_block_bits * v->levels)) + v->levels++; + + if (v->levels > DM_VERITY_MAX_LEVELS) { + ti->error = "Too many tree levels"; + r = -E2BIG; + goto bad; + } + + hash_position = v->hash_start; + for (i = v->levels - 1; i >= 0; i--) { + sector_t s; + v->hash_level_block[i] = hash_position; + s = (v->data_blocks + ((sector_t)1 << ((i + 1) * v->hash_per_block_bits)) - 1) + >> ((i + 1) * v->hash_per_block_bits); + if (hash_position + s < hash_position) { + ti->error = "Hash device offset overflow"; + r = -E2BIG; + goto bad; + } + hash_position += s; + } + v->hash_blocks = hash_position; + + v->bufio = dm_bufio_client_create(v->hash_dev->bdev, + 1 << v->hash_dev_block_bits, 1, sizeof(struct buffer_aux), + dm_bufio_alloc_callback, NULL); + if (IS_ERR(v->bufio)) { + ti->error = "Cannot initialize dm-bufio"; + r = PTR_ERR(v->bufio); + v->bufio = NULL; + goto bad; + } + + if (dm_bufio_get_device_size(v->bufio) < v->hash_blocks) { + ti->error = "Hash device is too small"; + r = -E2BIG; + goto bad; + } + + ti->per_bio_data_size = roundup(sizeof(struct dm_verity_io) + v->shash_descsize + v->digest_size * 2, __alignof__(struct dm_verity_io)); + + v->vec_mempool = mempool_create_kmalloc_pool(DM_VERITY_MEMPOOL_SIZE, + BIO_MAX_PAGES * sizeof(struct bio_vec)); + if (!v->vec_mempool) { + ti->error = "Cannot allocate vector mempool"; + r = -ENOMEM; + goto bad; + } + + /* WQ_UNBOUND greatly improves performance when running on ramdisk */ + v->verify_wq = alloc_workqueue("kverityd", WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM | WQ_UNBOUND, num_online_cpus()); + if (!v->verify_wq) { + ti->error = "Cannot allocate workqueue"; + r = -ENOMEM; + goto bad; + } + + return 0; + +bad: + verity_dtr(ti); + + return r; +} + +static struct target_type verity_target = { + .name = "verity", + .version = {1, 2, 0}, + .module = THIS_MODULE, + .ctr = verity_ctr, + .dtr = verity_dtr, + .map = verity_map, + .status = verity_status, + .ioctl = verity_ioctl, + .merge = verity_merge, + .iterate_devices = verity_iterate_devices, + .io_hints = verity_io_hints, +}; + +static int __init dm_verity_init(void) +{ + int r; + + r = dm_register_target(&verity_target); + if (r < 0) + DMERR("register failed %d", r); + + return r; +} + +static void __exit dm_verity_exit(void) +{ + dm_unregister_target(&verity_target); +} + +module_init(dm_verity_init); +module_exit(dm_verity_exit); + +MODULE_AUTHOR("Mikulas Patocka <mpatocka@redhat.com>"); +MODULE_AUTHOR("Mandeep Baines <msb@chromium.org>"); +MODULE_AUTHOR("Will Drewry <wad@chromium.org>"); +MODULE_DESCRIPTION(DM_NAME " target for transparent disk integrity checking"); +MODULE_LICENSE("GPL"); |