--- /dev/null
+/*
+ * 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");
Code Review / kvmfornfv.git / blobdiff