diff options
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/Kconfig | 45 | ||||
| -rw-r--r-- | drivers/md/Makefile | 6 | ||||
| -rw-r--r-- | drivers/md/dm-android-verity.c | 925 | ||||
| -rw-r--r-- | drivers/md/dm-android-verity.h | 121 | ||||
| -rw-r--r-- | drivers/md/dm-cache-target.c | 3 | ||||
| -rw-r--r-- | drivers/md/dm-crypt.c | 14 | ||||
| -rw-r--r-- | drivers/md/dm-ioctl.c | 39 | ||||
| -rw-r--r-- | drivers/md/dm-linear.c | 30 | ||||
| -rw-r--r-- | drivers/md/dm-snap.c | 6 | ||||
| -rw-r--r-- | drivers/md/dm-table.c | 1 | ||||
| -rw-r--r-- | drivers/md/dm-verity-fec.c | 870 | ||||
| -rw-r--r-- | drivers/md/dm-verity-fec.h | 159 | ||||
| -rw-r--r-- | drivers/md/dm-verity-target.c (renamed from drivers/md/dm-verity.c) | 632 | ||||
| -rw-r--r-- | drivers/md/dm-verity.h | 139 |
14 files changed, 2707 insertions, 283 deletions
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig index 7913fdcfc849..3d237a03dab3 100644 --- a/drivers/md/Kconfig +++ b/drivers/md/Kconfig @@ -458,6 +458,33 @@ config DM_VERITY If unsure, say N. +config DM_VERITY_HASH_PREFETCH_MIN_SIZE_128 + bool "Prefetch size 128" + +config DM_VERITY_HASH_PREFETCH_MIN_SIZE + int "Verity hash prefetch minimum size" + depends on DM_VERITY + range 1 4096 + default 128 if DM_VERITY_HASH_PREFETCH_MIN_SIZE_128 + default 1 + ---help--- + This sets minimum number of hash blocks to prefetch for dm-verity. + For devices like eMMC, having larger prefetch size like 128 can improve + performance with increased memory consumption for keeping more hashes + in RAM. + +config DM_VERITY_FEC + bool "Verity forward error correction support" + depends on DM_VERITY + select REED_SOLOMON + select REED_SOLOMON_DEC8 + ---help--- + Add forward error correction support to dm-verity. This option + makes it possible to use pre-generated error correction data to + recover from corrupted blocks. + + If unsure, say N. + config DM_SWITCH tristate "Switch target support (EXPERIMENTAL)" depends on BLK_DEV_DM @@ -488,4 +515,22 @@ config DM_LOG_WRITES If unsure, say N. +config DM_ANDROID_VERITY + tristate "Android verity target support" + depends on DM_VERITY + depends on X509_CERTIFICATE_PARSER + depends on SYSTEM_TRUSTED_KEYRING + depends on PUBLIC_KEY_ALGO_RSA + depends on KEYS + depends on ASYMMETRIC_KEY_TYPE + depends on ASYMMETRIC_PUBLIC_KEY_SUBTYPE + depends on MD_LINEAR + select DM_VERITY_HASH_PREFETCH_MIN_SIZE_128 + ---help--- + This device-mapper target is virtually a VERITY target. This + target is setup by reading the metadata contents piggybacked + to the actual data blocks in the block device. The signature + of the metadata contents are verified against the key included + in the system keyring. Upon success, the underlying verity + target is setup. endif # MD diff --git a/drivers/md/Makefile b/drivers/md/Makefile index f34979cd141a..32b5d0a90d60 100644 --- a/drivers/md/Makefile +++ b/drivers/md/Makefile @@ -16,6 +16,7 @@ dm-cache-mq-y += dm-cache-policy-mq.o dm-cache-smq-y += dm-cache-policy-smq.o dm-cache-cleaner-y += dm-cache-policy-cleaner.o dm-era-y += dm-era-target.o +dm-verity-y += dm-verity-target.o md-mod-y += md.o bitmap.o raid456-y += raid5.o raid5-cache.o @@ -59,7 +60,12 @@ obj-$(CONFIG_DM_CACHE_SMQ) += dm-cache-smq.o obj-$(CONFIG_DM_CACHE_CLEANER) += dm-cache-cleaner.o obj-$(CONFIG_DM_ERA) += dm-era.o obj-$(CONFIG_DM_LOG_WRITES) += dm-log-writes.o +obj-$(CONFIG_DM_ANDROID_VERITY) += dm-android-verity.o ifeq ($(CONFIG_DM_UEVENT),y) dm-mod-objs += dm-uevent.o endif + +ifeq ($(CONFIG_DM_VERITY_FEC),y) +dm-verity-objs += dm-verity-fec.o +endif diff --git a/drivers/md/dm-android-verity.c b/drivers/md/dm-android-verity.c new file mode 100644 index 000000000000..bb6c1285e499 --- /dev/null +++ b/drivers/md/dm-android-verity.c @@ -0,0 +1,925 @@ +/* + * Copyright (C) 2015 Google, Inc. + * + * This software is licensed under the terms of the GNU General Public + * License version 2, as published by the Free Software Foundation, and + * may be copied, distributed, and modified under those terms. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ + +#include <linux/buffer_head.h> +#include <linux/debugfs.h> +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/device-mapper.h> +#include <linux/errno.h> +#include <linux/fs.h> +#include <linux/fcntl.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/key.h> +#include <linux/module.h> +#include <linux/mount.h> +#include <linux/namei.h> +#include <linux/of.h> +#include <linux/reboot.h> +#include <linux/string.h> +#include <linux/vmalloc.h> + +#include <asm/setup.h> +#include <crypto/hash.h> +#include <crypto/public_key.h> +#include <crypto/sha.h> +#include <keys/asymmetric-type.h> +#include <keys/system_keyring.h> + +#include "dm-verity.h" +#include "dm-android-verity.h" + +static char verifiedbootstate[VERITY_COMMANDLINE_PARAM_LENGTH]; +static char veritymode[VERITY_COMMANDLINE_PARAM_LENGTH]; +static char veritykeyid[VERITY_DEFAULT_KEY_ID_LENGTH]; +static char buildvariant[BUILD_VARIANT]; + +static bool target_added; +static bool verity_enabled = true; +struct dentry *debug_dir; +static int android_verity_ctr(struct dm_target *ti, unsigned argc, char **argv); + +static struct target_type android_verity_target = { + .name = "android-verity", + .version = {1, 0, 0}, + .module = THIS_MODULE, + .ctr = android_verity_ctr, + .dtr = verity_dtr, + .map = verity_map, + .status = verity_status, + .prepare_ioctl = verity_prepare_ioctl, + .iterate_devices = verity_iterate_devices, + .io_hints = verity_io_hints, +}; + +static int __init verified_boot_state_param(char *line) +{ + strlcpy(verifiedbootstate, line, sizeof(verifiedbootstate)); + return 1; +} + +__setup("androidboot.verifiedbootstate=", verified_boot_state_param); + +static int __init verity_mode_param(char *line) +{ + strlcpy(veritymode, line, sizeof(veritymode)); + return 1; +} + +__setup("androidboot.veritymode=", verity_mode_param); + +static int __init verity_keyid_param(char *line) +{ + strlcpy(veritykeyid, line, sizeof(veritykeyid)); + return 1; +} + +__setup("veritykeyid=", verity_keyid_param); + +static int __init verity_buildvariant(char *line) +{ + strlcpy(buildvariant, line, sizeof(buildvariant)); + return 1; +} + +__setup("buildvariant=", verity_buildvariant); + +static inline bool default_verity_key_id(void) +{ + return veritykeyid[0] != '\0'; +} + +static inline bool is_eng(void) +{ + static const char typeeng[] = "eng"; + + return !strncmp(buildvariant, typeeng, sizeof(typeeng)); +} + +static inline bool is_userdebug(void) +{ + static const char typeuserdebug[] = "userdebug"; + + return !strncmp(buildvariant, typeuserdebug, sizeof(typeuserdebug)); +} + + +static int table_extract_mpi_array(struct public_key_signature *pks, + const void *data, size_t len) +{ + MPI mpi = mpi_read_raw_data(data, len); + + if (!mpi) { + DMERR("Error while allocating mpi array"); + return -ENOMEM; + } + + pks->mpi[0] = mpi; + pks->nr_mpi = 1; + return 0; +} + +static struct public_key_signature *table_make_digest( + enum hash_algo hash, + const void *table, + unsigned long table_len) +{ + struct public_key_signature *pks = NULL; + struct crypto_shash *tfm; + struct shash_desc *desc; + size_t digest_size, desc_size; + int ret; + + /* Allocate the hashing algorithm we're going to need and find out how + * big the hash operational data will be. + */ + tfm = crypto_alloc_shash(hash_algo_name[hash], 0, 0); + if (IS_ERR(tfm)) + return ERR_CAST(tfm); + + desc_size = crypto_shash_descsize(tfm) + sizeof(*desc); + digest_size = crypto_shash_digestsize(tfm); + + /* We allocate the hash operational data storage on the end of out + * context data and the digest output buffer on the end of that. + */ + ret = -ENOMEM; + pks = kzalloc(digest_size + sizeof(*pks) + desc_size, GFP_KERNEL); + if (!pks) + goto error; + + pks->pkey_hash_algo = hash; + pks->digest = (u8 *)pks + sizeof(*pks) + desc_size; + pks->digest_size = digest_size; + + desc = (struct shash_desc *)(pks + 1); + desc->tfm = tfm; + desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; + + ret = crypto_shash_init(desc); + if (ret < 0) + goto error; + + ret = crypto_shash_finup(desc, table, table_len, pks->digest); + if (ret < 0) + goto error; + + crypto_free_shash(tfm); + return pks; + +error: + kfree(pks); + crypto_free_shash(tfm); + return ERR_PTR(ret); +} + +static int read_block_dev(struct bio_read *payload, struct block_device *bdev, + sector_t offset, int length) +{ + struct bio *bio; + int err = 0, i; + + payload->number_of_pages = DIV_ROUND_UP(length, PAGE_SIZE); + + bio = bio_alloc(GFP_KERNEL, payload->number_of_pages); + if (!bio) { + DMERR("Error while allocating bio"); + return -ENOMEM; + } + + bio->bi_bdev = bdev; + bio->bi_iter.bi_sector = offset; + + payload->page_io = kzalloc(sizeof(struct page *) * + payload->number_of_pages, GFP_KERNEL); + if (!payload->page_io) { + DMERR("page_io array alloc failed"); + err = -ENOMEM; + goto free_bio; + } + + for (i = 0; i < payload->number_of_pages; i++) { + payload->page_io[i] = alloc_page(GFP_KERNEL); + if (!payload->page_io[i]) { + DMERR("alloc_page failed"); + err = -ENOMEM; + goto free_pages; + } + if (!bio_add_page(bio, payload->page_io[i], PAGE_SIZE, 0)) { + DMERR("bio_add_page error"); + err = -EIO; + goto free_pages; + } + } + + if (!submit_bio_wait(READ, bio)) + /* success */ + goto free_bio; + DMERR("bio read failed"); + err = -EIO; + +free_pages: + for (i = 0; i < payload->number_of_pages; i++) + if (payload->page_io[i]) + __free_page(payload->page_io[i]); + kfree(payload->page_io); +free_bio: + bio_put(bio); + return err; +} + +static inline u64 fec_div_round_up(u64 x, u64 y) +{ + u64 remainder; + + return div64_u64_rem(x, y, &remainder) + + (remainder > 0 ? 1 : 0); +} + +static inline void populate_fec_metadata(struct fec_header *header, + struct fec_ecc_metadata *ecc) +{ + ecc->blocks = fec_div_round_up(le64_to_cpu(header->inp_size), + FEC_BLOCK_SIZE); + ecc->roots = le32_to_cpu(header->roots); + ecc->start = le64_to_cpu(header->inp_size); +} + +static inline int validate_fec_header(struct fec_header *header, u64 offset) +{ + /* move offset to make the sanity check work for backup header + * as well. */ + offset -= offset % FEC_BLOCK_SIZE; + if (le32_to_cpu(header->magic) != FEC_MAGIC || + le32_to_cpu(header->version) != FEC_VERSION || + le32_to_cpu(header->size) != sizeof(struct fec_header) || + le32_to_cpu(header->roots) == 0 || + le32_to_cpu(header->roots) >= FEC_RSM) + return -EINVAL; + + return 0; +} + +static int extract_fec_header(dev_t dev, struct fec_header *fec, + struct fec_ecc_metadata *ecc) +{ + u64 device_size; + struct bio_read payload; + int i, err = 0; + struct block_device *bdev; + + bdev = blkdev_get_by_dev(dev, FMODE_READ, NULL); + + if (IS_ERR_OR_NULL(bdev)) { + DMERR("bdev get error"); + return PTR_ERR(bdev); + } + + device_size = i_size_read(bdev->bd_inode); + + /* fec metadata size is a power of 2 and PAGE_SIZE + * is a power of 2 as well. + */ + BUG_ON(FEC_BLOCK_SIZE > PAGE_SIZE); + /* 512 byte sector alignment */ + BUG_ON(((device_size - FEC_BLOCK_SIZE) % (1 << SECTOR_SHIFT)) != 0); + + err = read_block_dev(&payload, bdev, (device_size - + FEC_BLOCK_SIZE) / (1 << SECTOR_SHIFT), FEC_BLOCK_SIZE); + if (err) { + DMERR("Error while reading verity metadata"); + goto error; + } + + BUG_ON(sizeof(struct fec_header) > PAGE_SIZE); + memcpy(fec, page_address(payload.page_io[0]), + sizeof(*fec)); + + ecc->valid = true; + if (validate_fec_header(fec, device_size - FEC_BLOCK_SIZE)) { + /* Try the backup header */ + memcpy(fec, page_address(payload.page_io[0]) + FEC_BLOCK_SIZE + - sizeof(*fec) , + sizeof(*fec)); + if (validate_fec_header(fec, device_size - + sizeof(struct fec_header))) + ecc->valid = false; + } + + if (ecc->valid) + populate_fec_metadata(fec, ecc); + + for (i = 0; i < payload.number_of_pages; i++) + __free_page(payload.page_io[i]); + kfree(payload.page_io); + +error: + blkdev_put(bdev, FMODE_READ); + return err; +} +static void find_metadata_offset(struct fec_header *fec, + struct block_device *bdev, u64 *metadata_offset) +{ + u64 device_size; + + device_size = i_size_read(bdev->bd_inode); + + if (le32_to_cpu(fec->magic) == FEC_MAGIC) + *metadata_offset = le64_to_cpu(fec->inp_size) - + VERITY_METADATA_SIZE; + else + *metadata_offset = device_size - VERITY_METADATA_SIZE; +} + +static int find_size(dev_t dev, u64 *device_size) +{ + struct block_device *bdev; + + bdev = blkdev_get_by_dev(dev, FMODE_READ, NULL); + if (IS_ERR_OR_NULL(bdev)) { + DMERR("blkdev_get_by_dev failed"); + return PTR_ERR(bdev); + } + + *device_size = i_size_read(bdev->bd_inode); + *device_size >>= SECTOR_SHIFT; + + DMINFO("blkdev size in sectors: %llu", *device_size); + blkdev_put(bdev, FMODE_READ); + return 0; +} + +static int verify_header(struct android_metadata_header *header) +{ + int retval = -EINVAL; + + if (is_userdebug() && le32_to_cpu(header->magic_number) == + VERITY_METADATA_MAGIC_DISABLE) + return VERITY_STATE_DISABLE; + + if (!(le32_to_cpu(header->magic_number) == + VERITY_METADATA_MAGIC_NUMBER) || + (le32_to_cpu(header->magic_number) == + VERITY_METADATA_MAGIC_DISABLE)) { + DMERR("Incorrect magic number"); + return retval; + } + + if (le32_to_cpu(header->protocol_version) != + VERITY_METADATA_VERSION) { + DMERR("Unsupported version %u", + le32_to_cpu(header->protocol_version)); + return retval; + } + + return 0; +} + +static int extract_metadata(dev_t dev, struct fec_header *fec, + struct android_metadata **metadata, + bool *verity_enabled) +{ + struct block_device *bdev; + struct android_metadata_header *header; + int i; + u32 table_length, copy_length, offset; + u64 metadata_offset; + struct bio_read payload; + int err = 0; + + bdev = blkdev_get_by_dev(dev, FMODE_READ, NULL); + + if (IS_ERR_OR_NULL(bdev)) { + DMERR("blkdev_get_by_dev failed"); + return -ENODEV; + } + + find_metadata_offset(fec, bdev, &metadata_offset); + + /* Verity metadata size is a power of 2 and PAGE_SIZE + * is a power of 2 as well. + * PAGE_SIZE is also a multiple of 512 bytes. + */ + if (VERITY_METADATA_SIZE > PAGE_SIZE) + BUG_ON(VERITY_METADATA_SIZE % PAGE_SIZE != 0); + /* 512 byte sector alignment */ + BUG_ON(metadata_offset % (1 << SECTOR_SHIFT) != 0); + + err = read_block_dev(&payload, bdev, metadata_offset / + (1 << SECTOR_SHIFT), VERITY_METADATA_SIZE); + if (err) { + DMERR("Error while reading verity metadata"); + goto blkdev_release; + } + + header = kzalloc(sizeof(*header), GFP_KERNEL); + if (!header) { + DMERR("kzalloc failed for header"); + err = -ENOMEM; + goto free_payload; + } + + memcpy(header, page_address(payload.page_io[0]), + sizeof(*header)); + + DMINFO("bio magic_number:%u protocol_version:%d table_length:%u", + le32_to_cpu(header->magic_number), + le32_to_cpu(header->protocol_version), + le32_to_cpu(header->table_length)); + + err = verify_header(header); + + if (err == VERITY_STATE_DISABLE) { + DMERR("Mounting root with verity disabled"); + *verity_enabled = false; + /* we would still have to read the metadata to figure out + * the data blocks size. Or may be could map the entire + * partition similar to mounting the device. + * + * Reset error as well as the verity_enabled flag is changed. + */ + err = 0; + } else if (err) + goto free_header; + + *metadata = kzalloc(sizeof(**metadata), GFP_KERNEL); + if (!*metadata) { + DMERR("kzalloc for metadata failed"); + err = -ENOMEM; + goto free_header; + } + + (*metadata)->header = header; + table_length = le32_to_cpu(header->table_length); + + if (table_length == 0 || + table_length > (VERITY_METADATA_SIZE - + sizeof(struct android_metadata_header))) { + DMERR("table_length too long"); + err = -EINVAL; + goto free_metadata; + } + + (*metadata)->verity_table = kzalloc(table_length + 1, GFP_KERNEL); + + if (!(*metadata)->verity_table) { + DMERR("kzalloc verity_table failed"); + err = -ENOMEM; + goto free_metadata; + } + + if (sizeof(struct android_metadata_header) + + table_length <= PAGE_SIZE) { + memcpy((*metadata)->verity_table, + page_address(payload.page_io[0]) + + sizeof(struct android_metadata_header), + table_length); + } else { + copy_length = PAGE_SIZE - + sizeof(struct android_metadata_header); + memcpy((*metadata)->verity_table, + page_address(payload.page_io[0]) + + sizeof(struct android_metadata_header), + copy_length); + table_length -= copy_length; + offset = copy_length; + i = 1; + while (table_length != 0) { + if (table_length > PAGE_SIZE) { + memcpy((*metadata)->verity_table + offset, + page_address(payload.page_io[i]), + PAGE_SIZE); + offset += PAGE_SIZE; + table_length -= PAGE_SIZE; + } else { + memcpy((*metadata)->verity_table + offset, + page_address(payload.page_io[i]), + table_length); + table_length = 0; + } + i++; + } + } + (*metadata)->verity_table[table_length] = '\0'; + + DMINFO("verity_table: %s", (*metadata)->verity_table); + goto free_payload; + +free_metadata: + kfree(*metadata); +free_header: + kfree(header); +free_payload: + for (i = 0; i < payload.number_of_pages; i++) + if (payload.page_io[i]) + __free_page(payload.page_io[i]); + kfree(payload.page_io); +blkdev_release: + blkdev_put(bdev, FMODE_READ); + return err; +} + +/* helper functions to extract properties from dts */ +const char *find_dt_value(const char *name) +{ + struct device_node *firmware; + const char *value; + + firmware = of_find_node_by_path("/firmware/android"); + if (!firmware) + return NULL; + value = of_get_property(firmware, name, NULL); + of_node_put(firmware); + + return value; +} + +static int verity_mode(void) +{ + static const char enforcing[] = "enforcing"; + static const char verified_mode_prop[] = "veritymode"; + const char *value; + + value = find_dt_value(verified_mode_prop); + if (!value) + value = veritymode; + if (!strncmp(value, enforcing, sizeof(enforcing) - 1)) + return DM_VERITY_MODE_RESTART; + + return DM_VERITY_MODE_EIO; +} + +static int verify_verity_signature(char *key_id, + struct android_metadata *metadata) +{ + key_ref_t key_ref; + struct key *key; + struct public_key_signature *pks = NULL; + int retval = -EINVAL; + + key_ref = keyring_search(make_key_ref(system_trusted_keyring, 1), + &key_type_asymmetric, key_id); + + if (IS_ERR(key_ref)) { + DMERR("keyring: key not found"); + return -ENOKEY; + } + + key = key_ref_to_ptr(key_ref); + + pks = table_make_digest(HASH_ALGO_SHA256, + (const void *)metadata->verity_table, + le32_to_cpu(metadata->header->table_length)); + + if (IS_ERR(pks)) { + DMERR("hashing failed"); + goto error; + } + + retval = table_extract_mpi_array(pks, &metadata->header->signature[0], + RSANUMBYTES); + if (retval < 0) { + DMERR("Error extracting mpi %d", retval); + goto error; + } + + retval = verify_signature(key, pks); + mpi_free(pks->rsa.s); +error: + kfree(pks); + key_put(key); + + return retval; +} + +static void handle_error(void) +{ + int mode = verity_mode(); + if (mode == DM_VERITY_MODE_RESTART) { + DMERR("triggering restart"); + kernel_restart("dm-verity device corrupted"); + } else { + DMERR("Mounting verity root failed"); + } +} + +static inline bool test_mult_overflow(sector_t a, u32 b) +{ + sector_t r = (sector_t)~0ULL; + + sector_div(r, b); + return a > r; +} + +static int add_as_linear_device(struct dm_target *ti, char *dev) +{ + /*Move to linear mapping defines*/ + char *linear_table_args[DM_LINEAR_ARGS] = {dev, + DM_LINEAR_TARGET_OFFSET}; + int err = 0; + + android_verity_target.dtr = dm_linear_dtr, + android_verity_target.map = dm_linear_map, + android_verity_target.status = dm_linear_status, + android_verity_target.prepare_ioctl = dm_linear_prepare_ioctl, + android_verity_target.iterate_devices = dm_linear_iterate_devices, + android_verity_target.io_hints = NULL; + + err = dm_linear_ctr(ti, DM_LINEAR_ARGS, linear_table_args); + + if (!err) { + DMINFO("Added android-verity as a linear target"); + target_added = true; + } else + DMERR("Failed to add android-verity as linear target"); + + return err; +} + +/* + * Target parameters: + * <key id> Key id of the public key in the system keyring. + * Verity metadata's signature would be verified against + * this. If the key id contains spaces, replace them + * with '#'. + * <block device> The block device for which dm-verity is being setup. + */ +static int android_verity_ctr(struct dm_target *ti, unsigned argc, char **argv) +{ + dev_t uninitialized_var(dev); + struct android_metadata *metadata = NULL; + int err = 0, i, mode; + char *key_id, *table_ptr, dummy, *target_device, + *verity_table_args[VERITY_TABLE_ARGS + 2 + VERITY_TABLE_OPT_FEC_ARGS]; + /* One for specifying number of opt args and one for mode */ + sector_t data_sectors; + u32 data_block_size; + unsigned int no_of_args = VERITY_TABLE_ARGS + 2 + VERITY_TABLE_OPT_FEC_ARGS; + struct fec_header uninitialized_var(fec); + struct fec_ecc_metadata uninitialized_var(ecc); + char buf[FEC_ARG_LENGTH], *buf_ptr; + unsigned long long tmpll; + u64 uninitialized_var(device_size); + + if (argc == 1) { + /* Use the default keyid */ + if (default_verity_key_id()) + key_id = veritykeyid; + else if (!is_eng()) { + DMERR("veritykeyid= is not set"); + handle_error(); + return -EINVAL; + } + } else if (argc == 2) + key_id = argv[1]; + else { + DMERR("Incorrect number of arguments"); + handle_error(); + return -EINVAL; + } + + target_device = argv[0]; + + dev = name_to_dev_t(target_device); + if (!dev) { + DMERR("no dev found for %s", target_device); + handle_error(); + return -EINVAL; + } + + if (is_eng()) { + err = find_size(dev, &device_size); + if (err) { + DMERR("error finding bdev size"); + handle_error(); + return err; + } + + ti->len = device_size; + err = add_as_linear_device(ti, target_device); + if (err) { + handle_error(); + return err; + } + verity_enabled = false; + return 0; + } + + strreplace(key_id, '#', ' '); + + DMINFO("key:%s dev:%s", key_id, target_device); + + if (extract_fec_header(dev, &fec, &ecc)) { + DMERR("Error while extracting fec header"); + handle_error(); + return -EINVAL; + } + + err = extract_metadata(dev, &fec, &metadata, &verity_enabled); + + if (err) { + DMERR("Error while extracting metadata"); + handle_error(); + goto free_metadata; + } + + if (verity_enabled) { + err = verify_verity_signature(key_id, metadata); + + if (err) { + DMERR("Signature verification failed"); + handle_error(); + goto free_metadata; + } else + DMINFO("Signature verification success"); + } + + table_ptr = metadata->verity_table; + + for (i = 0; i < VERITY_TABLE_ARGS; i++) { + verity_table_args[i] = strsep(&table_ptr, " "); + if (verity_table_args[i] == NULL) + break; + } + + if (i != VERITY_TABLE_ARGS) { + DMERR("Verity table not in the expected format"); + err = -EINVAL; + handle_error(); + goto free_metadata; + } + + if (sscanf(verity_table_args[5], "%llu%c", &tmpll, &dummy) + != 1) { + DMERR("Verity table not in the expected format"); + handle_error(); + err = -EINVAL; + goto free_metadata; + } + + if (tmpll > ULONG_MAX) { + DMERR("<num_data_blocks> too large. Forgot to turn on CONFIG_LBDAF?"); + handle_error(); + err = -EINVAL; + goto free_metadata; + } + + data_sectors = tmpll; + + if (sscanf(verity_table_args[3], "%u%c", &data_block_size, &dummy) + != 1) { + DMERR("Verity table not in the expected format"); + handle_error(); + err = -EINVAL; + goto free_metadata; + } + + if (test_mult_overflow(data_sectors, data_block_size >> + SECTOR_SHIFT)) { + DMERR("data_sectors too large"); + handle_error(); + err = -EOVERFLOW; + goto free_metadata; + } + + data_sectors *= data_block_size >> SECTOR_SHIFT; + DMINFO("Data sectors %llu", (unsigned long long)data_sectors); + + /* update target length */ + ti->len = data_sectors; + + /* Setup linear target and free */ + if (!verity_enabled) { + err = add_as_linear_device(ti, target_device); + goto free_metadata; + } + + /*substitute data_dev and hash_dev*/ + verity_table_args[1] = target_device; + verity_table_args[2] = target_device; + + mode = verity_mode(); + + if (ecc.valid && IS_BUILTIN(CONFIG_DM_VERITY_FEC)) { + if (mode) { + err = snprintf(buf, FEC_ARG_LENGTH, + "%u %s " VERITY_TABLE_OPT_FEC_FORMAT, + 1 + VERITY_TABLE_OPT_FEC_ARGS, + mode == DM_VERITY_MODE_RESTART ? + VERITY_TABLE_OPT_RESTART : + VERITY_TABLE_OPT_LOGGING, + target_device, + ecc.start / FEC_BLOCK_SIZE, ecc.blocks, + ecc.roots); + } else { + err = snprintf(buf, FEC_ARG_LENGTH, + "%u " VERITY_TABLE_OPT_FEC_FORMAT, + VERITY_TABLE_OPT_FEC_ARGS, target_device, + ecc.start / FEC_BLOCK_SIZE, ecc.blocks, + ecc.roots); + } + } else if (mode) { + err = snprintf(buf, FEC_ARG_LENGTH, + "2 " VERITY_TABLE_OPT_IGNZERO " %s", + mode == DM_VERITY_MODE_RESTART ? + VERITY_TABLE_OPT_RESTART : VERITY_TABLE_OPT_LOGGING); + } else { + err = snprintf(buf, FEC_ARG_LENGTH, "1 %s", + "ignore_zero_blocks"); + } + + if (err < 0 || err >= FEC_ARG_LENGTH) + goto free_metadata; + + buf_ptr = buf; + + for (i = VERITY_TABLE_ARGS; i < (VERITY_TABLE_ARGS + + VERITY_TABLE_OPT_FEC_ARGS + 2); i++) { + verity_table_args[i] = strsep(&buf_ptr, " "); + if (verity_table_args[i] == NULL) { + no_of_args = i; + break; + } + } + + err = verity_ctr(ti, no_of_args, verity_table_args); + + if (err) + DMERR("android-verity failed to mount as verity target"); + else { + target_added = true; + DMINFO("android-verity mounted as verity target"); + } + +free_metadata: + if (metadata) { + kfree(metadata->header); + kfree(metadata->verity_table); + } + kfree(metadata); + return err; +} + +static int __init dm_android_verity_init(void) +{ + int r; + struct dentry *file; + + r = dm_register_target(&android_verity_target); + if (r < 0) + DMERR("register failed %d", r); + + /* Tracks the status of the last added target */ + debug_dir = debugfs_create_dir("android_verity", NULL); + + if (IS_ERR_OR_NULL(debug_dir)) { + DMERR("Cannot create android_verity debugfs directory: %ld", + PTR_ERR(debug_dir)); + goto end; + } + + file = debugfs_create_bool("target_added", S_IRUGO, debug_dir, + &target_added); + + if (IS_ERR_OR_NULL(file)) { + DMERR("Cannot create android_verity debugfs directory: %ld", + PTR_ERR(debug_dir)); + debugfs_remove_recursive(debug_dir); + goto end; + } + + file = debugfs_create_bool("verity_enabled", S_IRUGO, debug_dir, + &verity_enabled); + + if (IS_ERR_OR_NULL(file)) { + DMERR("Cannot create android_verity debugfs directory: %ld", + PTR_ERR(debug_dir)); + debugfs_remove_recursive(debug_dir); + } + +end: + return r; +} + +static void __exit dm_android_verity_exit(void) +{ + if (!IS_ERR_OR_NULL(debug_dir)) + debugfs_remove_recursive(debug_dir); + + dm_unregister_target(&android_verity_target); +} + +module_init(dm_android_verity_init); +module_exit(dm_android_verity_exit); diff --git a/drivers/md/dm-android-verity.h b/drivers/md/dm-android-verity.h new file mode 100644 index 000000000000..0c7ff6afec69 --- /dev/null +++ b/drivers/md/dm-android-verity.h @@ -0,0 +1,121 @@ +/* + * Copyright (C) 2015 Google, Inc. + * + * This software is licensed under the terms of the GNU General Public + * License version 2, as published by the Free Software Foundation, and + * may be copied, distributed, and modified under those terms. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ + +#ifndef DM_ANDROID_VERITY_H +#define DM_ANDROID_VERITY_H + +#include <crypto/sha.h> + +#define RSANUMBYTES 256 +#define VERITY_METADATA_MAGIC_NUMBER 0xb001b001 +#define VERITY_METADATA_MAGIC_DISABLE 0x46464f56 +#define VERITY_METADATA_VERSION 0 +#define VERITY_STATE_DISABLE 1 +#define DATA_BLOCK_SIZE (4 * 1024) +#define VERITY_METADATA_SIZE (8 * DATA_BLOCK_SIZE) +#define VERITY_TABLE_ARGS 10 +#define VERITY_COMMANDLINE_PARAM_LENGTH 20 +#define BUILD_VARIANT 20 + +/* + * <subject>:<sha1-id> is the format for the identifier. + * subject can either be the Common Name(CN) + Organization Name(O) or + * just the CN if the it is prefixed with O + * From https://tools.ietf.org/html/rfc5280#appendix-A + * ub-organization-name-length INTEGER ::= 64 + * ub-common-name-length INTEGER ::= 64 + * + * http://lxr.free-electrons.com/source/crypto/asymmetric_keys/x509_cert_parser.c?v=3.9#L278 + * ctx->o_size + 2 + ctx->cn_size + 1 + * + 41 characters for ":" and sha1 id + * 64 + 2 + 64 + 1 + 1 + 40 (172) + * setting VERITY_DEFAULT_KEY_ID_LENGTH to 200 characters. + */ +#define VERITY_DEFAULT_KEY_ID_LENGTH 200 + +#define FEC_MAGIC 0xFECFECFE +#define FEC_BLOCK_SIZE (4 * 1024) +#define FEC_VERSION 0 +#define FEC_RSM 255 +#define FEC_ARG_LENGTH 300 + +#define VERITY_TABLE_OPT_RESTART "restart_on_corruption" +#define VERITY_TABLE_OPT_LOGGING "ignore_corruption" +#define VERITY_TABLE_OPT_IGNZERO "ignore_zero_blocks" + +#define VERITY_TABLE_OPT_FEC_FORMAT \ + "use_fec_from_device %s fec_start %llu fec_blocks %llu fec_roots %u ignore_zero_blocks" +#define VERITY_TABLE_OPT_FEC_ARGS 9 + +#define VERITY_DEBUG 0 + +#define DM_MSG_PREFIX "android-verity" + +#define DM_LINEAR_ARGS 2 +#define DM_LINEAR_TARGET_OFFSET "0" + +/* + * There can be two formats. + * if fec is present + * <data_blocks> <verity_tree> <verity_metdata_32K><fec_data><fec_data_4K> + * if fec is not present + * <data_blocks> <verity_tree> <verity_metdata_32K> + */ +struct fec_header { + __le32 magic; + __le32 version; + __le32 size; + __le32 roots; + __le32 fec_size; + __le64 inp_size; + u8 hash[SHA256_DIGEST_SIZE]; +} __attribute__((packed)); + +struct android_metadata_header { + __le32 magic_number; + __le32 protocol_version; + char signature[RSANUMBYTES]; + __le32 table_length; +}; + +struct android_metadata { + struct android_metadata_header *header; + char *verity_table; +}; + +struct fec_ecc_metadata { + bool valid; + u32 roots; + u64 blocks; + u64 rounds; + u64 start; +}; + +struct bio_read { + struct page **page_io; + int number_of_pages; +}; + +extern struct target_type linear_target; + +extern void dm_linear_dtr(struct dm_target *ti); +extern int dm_linear_map(struct dm_target *ti, struct bio *bio); +extern void dm_linear_status(struct dm_target *ti, status_type_t type, + unsigned status_flags, char *result, unsigned maxlen); +extern int dm_linear_prepare_ioctl(struct dm_target *ti, + struct block_device **bdev, fmode_t *mode); +extern int dm_linear_iterate_devices(struct dm_target *ti, + iterate_devices_callout_fn fn, void *data); +extern int dm_linear_ctr(struct dm_target *ti, unsigned int argc, char **argv); +#endif /* DM_ANDROID_VERITY_H */ diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c index 515f83e7d9ab..bb9b92ebbf8e 100644 --- a/drivers/md/dm-cache-target.c +++ b/drivers/md/dm-cache-target.c @@ -118,14 +118,12 @@ static void iot_io_end(struct io_tracker *iot, sector_t len) */ struct dm_hook_info { bio_end_io_t *bi_end_io; - void *bi_private; }; static void dm_hook_bio(struct dm_hook_info *h, struct bio *bio, bio_end_io_t *bi_end_io, void *bi_private) { h->bi_end_io = bio->bi_end_io; - h->bi_private = bio->bi_private; bio->bi_end_io = bi_end_io; bio->bi_private = bi_private; @@ -134,7 +132,6 @@ static void dm_hook_bio(struct dm_hook_info *h, struct bio *bio, static void dm_unhook_bio(struct dm_hook_info *h, struct bio *bio) { bio->bi_end_io = h->bi_end_io; - bio->bi_private = h->bi_private; } /*----------------------------------------------------------------*/ diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c index de628883ee3d..799b9a5ad4f5 100644 --- a/drivers/md/dm-crypt.c +++ b/drivers/md/dm-crypt.c @@ -1863,16 +1863,24 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv) } ret = -ENOMEM; - cc->io_queue = alloc_workqueue("kcryptd_io", WQ_MEM_RECLAIM, 1); + cc->io_queue = alloc_workqueue("kcryptd_io", + WQ_HIGHPRI | + WQ_MEM_RECLAIM, + 1); if (!cc->io_queue) { ti->error = "Couldn't create kcryptd io queue"; goto bad; } if (test_bit(DM_CRYPT_SAME_CPU, &cc->flags)) - cc->crypt_queue = alloc_workqueue("kcryptd", WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM, 1); + cc->crypt_queue = alloc_workqueue("kcryptd", + WQ_HIGHPRI | + WQ_MEM_RECLAIM, 1); else - cc->crypt_queue = alloc_workqueue("kcryptd", WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM | WQ_UNBOUND, + cc->crypt_queue = alloc_workqueue("kcryptd", + WQ_HIGHPRI | + WQ_MEM_RECLAIM | + WQ_UNBOUND, num_online_cpus()); if (!cc->crypt_queue) { ti->error = "Couldn't create kcryptd queue"; diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c index 80a439543259..bc5e9a5b1f30 100644 --- a/drivers/md/dm-ioctl.c +++ b/drivers/md/dm-ioctl.c @@ -1923,6 +1923,45 @@ void dm_interface_exit(void) dm_hash_exit(); } + +/** + * dm_ioctl_export - Permanently export a mapped device via the ioctl interface + * @md: Pointer to mapped_device + * @name: Buffer (size DM_NAME_LEN) for name + * @uuid: Buffer (size DM_UUID_LEN) for uuid or NULL if not desired + */ +int dm_ioctl_export(struct mapped_device *md, const char *name, + const char *uuid) +{ + int r = 0; + struct hash_cell *hc; + + if (!md) { + r = -ENXIO; + goto out; + } + + /* The name and uuid can only be set once. */ + mutex_lock(&dm_hash_cells_mutex); + hc = dm_get_mdptr(md); + mutex_unlock(&dm_hash_cells_mutex); + if (hc) { + DMERR("%s: already exported", dm_device_name(md)); + r = -ENXIO; + goto out; + } + + r = dm_hash_insert(name, uuid, md); + if (r) { + DMERR("%s: could not bind to '%s'", dm_device_name(md), name); + goto out; + } + + /* Let udev know we've changed. */ + dm_kobject_uevent(md, KOBJ_CHANGE, dm_get_event_nr(md)); +out: + return r; +} /** * dm_copy_name_and_uuid - Copy mapped device name & uuid into supplied buffers * @md: Pointer to mapped_device diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c index 05c35aacb3aa..2ff5f32a4b99 100644 --- a/drivers/md/dm-linear.c +++ b/drivers/md/dm-linear.c @@ -25,7 +25,7 @@ struct linear_c { /* * Construct a linear mapping: <dev_path> <offset> */ -static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv) +int dm_linear_ctr(struct dm_target *ti, unsigned int argc, char **argv) { struct linear_c *lc; unsigned long long tmp; @@ -66,14 +66,16 @@ static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv) kfree(lc); return ret; } +EXPORT_SYMBOL_GPL(dm_linear_ctr); -static void linear_dtr(struct dm_target *ti) +void dm_linear_dtr(struct dm_target *ti) { struct linear_c *lc = (struct linear_c *) ti->private; dm_put_device(ti, lc->dev); kfree(lc); } +EXPORT_SYMBOL_GPL(dm_linear_dtr); static sector_t linear_map_sector(struct dm_target *ti, sector_t bi_sector) { @@ -92,14 +94,15 @@ static void linear_map_bio(struct dm_target *ti, struct bio *bio) linear_map_sector(ti, bio->bi_iter.bi_sector); } -static int linear_map(struct dm_target *ti, struct bio *bio) +int dm_linear_map(struct dm_target *ti, struct bio *bio) { linear_map_bio(ti, bio); return DM_MAPIO_REMAPPED; } +EXPORT_SYMBOL_GPL(dm_linear_map); -static void linear_status(struct dm_target *ti, status_type_t type, +void dm_linear_status(struct dm_target *ti, status_type_t type, unsigned status_flags, char *result, unsigned maxlen) { struct linear_c *lc = (struct linear_c *) ti->private; @@ -115,8 +118,9 @@ static void linear_status(struct dm_target *ti, status_type_t type, break; } } +EXPORT_SYMBOL_GPL(dm_linear_status); -static int linear_prepare_ioctl(struct dm_target *ti, +int dm_linear_prepare_ioctl(struct dm_target *ti, struct block_device **bdev, fmode_t *mode) { struct linear_c *lc = (struct linear_c *) ti->private; @@ -132,25 +136,27 @@ static int linear_prepare_ioctl(struct dm_target *ti, return 1; return 0; } +EXPORT_SYMBOL_GPL(dm_linear_prepare_ioctl); -static int linear_iterate_devices(struct dm_target *ti, +int dm_linear_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data) { struct linear_c *lc = ti->private; return fn(ti, lc->dev, lc->start, ti->len, data); } +EXPORT_SYMBOL_GPL(dm_linear_iterate_devices); static struct target_type linear_target = { .name = "linear", .version = {1, 2, 1}, .module = THIS_MODULE, - .ctr = linear_ctr, - .dtr = linear_dtr, - .map = linear_map, - .status = linear_status, - .prepare_ioctl = linear_prepare_ioctl, - .iterate_devices = linear_iterate_devices, + .ctr = dm_linear_ctr, + .dtr = dm_linear_dtr, + .map = dm_linear_map, + .status = dm_linear_status, + .prepare_ioctl = dm_linear_prepare_ioctl, + .iterate_devices = dm_linear_iterate_devices, }; int __init dm_linear_init(void) diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index e108deebbaaa..e4d1bafe78c1 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -207,7 +207,6 @@ struct dm_snap_pending_exception { */ struct bio *full_bio; bio_end_io_t *full_bio_end_io; - void *full_bio_private; }; /* @@ -1495,10 +1494,8 @@ out: snapshot_bios = bio_list_get(&pe->snapshot_bios); origin_bios = bio_list_get(&pe->origin_bios); full_bio = pe->full_bio; - if (full_bio) { + if (full_bio) full_bio->bi_end_io = pe->full_bio_end_io; - full_bio->bi_private = pe->full_bio_private; - } increment_pending_exceptions_done_count(); up_write(&s->lock); @@ -1604,7 +1601,6 @@ static void start_full_bio(struct dm_snap_pending_exception *pe, pe->full_bio = bio; pe->full_bio_end_io = bio->bi_end_io; - pe->full_bio_private = bio->bi_private; callback_data = dm_kcopyd_prepare_callback(s->kcopyd_client, copy_callback, pe); diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index cb5d0daf53bb..b3d78bba3a79 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -11,6 +11,7 @@ #include <linux/vmalloc.h> #include <linux/blkdev.h> #include <linux/namei.h> +#include <linux/mount.h> #include <linux/ctype.h> #include <linux/string.h> #include <linux/slab.h> diff --git a/drivers/md/dm-verity-fec.c b/drivers/md/dm-verity-fec.c new file mode 100644 index 000000000000..1dd667b97530 --- /dev/null +++ b/drivers/md/dm-verity-fec.c @@ -0,0 +1,870 @@ +/* + * Copyright (C) 2015 Google, Inc. + * + * Author: Sami Tolvanen <samitolvanen@google.com> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the Free + * Software Foundation; either version 2 of the License, or (at your option) + * any later version. + */ + +#include "dm-verity-fec.h" +#include <linux/math64.h> +#include <linux/sysfs.h> + +#define DM_MSG_PREFIX "verity-fec" + +/* + * If error correction has been configured, returns true. + */ +bool verity_fec_is_enabled(struct dm_verity *v) +{ + return v->fec && v->fec->dev; +} + +/* + * Return a pointer to dm_verity_fec_io after dm_verity_io and its variable + * length fields. + */ +static inline struct dm_verity_fec_io *fec_io(struct dm_verity_io *io) +{ + return (struct dm_verity_fec_io *) verity_io_digest_end(io->v, io); +} + +/* + * Return an interleaved offset for a byte in RS block. + */ +static inline u64 fec_interleave(struct dm_verity *v, u64 offset) +{ + u32 mod; + + mod = do_div(offset, v->fec->rsn); + return offset + mod * (v->fec->rounds << v->data_dev_block_bits); +} + +/* + * Decode an RS block using Reed-Solomon. + */ +static int fec_decode_rs8(struct dm_verity *v, struct dm_verity_fec_io *fio, + u8 *data, u8 *fec, int neras) +{ + int i; + uint16_t par[DM_VERITY_FEC_RSM - DM_VERITY_FEC_MIN_RSN]; + + for (i = 0; i < v->fec->roots; i++) + par[i] = fec[i]; + + return decode_rs8(fio->rs, data, par, v->fec->rsn, NULL, neras, + fio->erasures, 0, NULL); +} + +/* + * Read error-correcting codes for the requested RS block. Returns a pointer + * to the data block. Caller is responsible for releasing buf. + */ +static u8 *fec_read_parity(struct dm_verity *v, u64 rsb, int index, + unsigned *offset, struct dm_buffer **buf) +{ + u64 position, block; + u8 *res; + + position = (index + rsb) * v->fec->roots; + block = position >> v->data_dev_block_bits; + *offset = (unsigned)(position - (block << v->data_dev_block_bits)); + + res = dm_bufio_read(v->fec->bufio, v->fec->start + block, buf); + if (unlikely(IS_ERR(res))) { + DMERR("%s: FEC %llu: parity read failed (block %llu): %ld", + v->data_dev->name, (unsigned long long)rsb, + (unsigned long long)(v->fec->start + block), + PTR_ERR(res)); + *buf = NULL; + } + + return res; +} + +/* Loop over each preallocated buffer slot. */ +#define fec_for_each_prealloc_buffer(__i) \ + for (__i = 0; __i < DM_VERITY_FEC_BUF_PREALLOC; __i++) + +/* Loop over each extra buffer slot. */ +#define fec_for_each_extra_buffer(io, __i) \ + for (__i = DM_VERITY_FEC_BUF_PREALLOC; __i < DM_VERITY_FEC_BUF_MAX; __i++) + +/* Loop over each allocated buffer. */ +#define fec_for_each_buffer(io, __i) \ + for (__i = 0; __i < (io)->nbufs; __i++) + +/* Loop over each RS block in each allocated buffer. */ +#define fec_for_each_buffer_rs_block(io, __i, __j) \ + fec_for_each_buffer(io, __i) \ + for (__j = 0; __j < 1 << DM_VERITY_FEC_BUF_RS_BITS; __j++) + +/* + * Return a pointer to the current RS block when called inside + * fec_for_each_buffer_rs_block. + */ +static inline u8 *fec_buffer_rs_block(struct dm_verity *v, + struct dm_verity_fec_io *fio, + unsigned i, unsigned j) +{ + return &fio->bufs[i][j * v->fec->rsn]; +} + +/* + * Return an index to the current RS block when called inside + * fec_for_each_buffer_rs_block. + */ +static inline unsigned fec_buffer_rs_index(unsigned i, unsigned j) +{ + return (i << DM_VERITY_FEC_BUF_RS_BITS) + j; +} + +/* + * Decode all RS blocks from buffers and copy corrected bytes into fio->output + * starting from block_offset. + */ +static int fec_decode_bufs(struct dm_verity *v, struct dm_verity_fec_io *fio, + u64 rsb, int byte_index, unsigned block_offset, + int neras) +{ + int r, corrected = 0, res; + struct dm_buffer *buf; + unsigned n, i, offset; + u8 *par, *block; + + par = fec_read_parity(v, rsb, block_offset, &offset, &buf); + if (IS_ERR(par)) + return PTR_ERR(par); + + /* + * Decode the RS blocks we have in bufs. Each RS block results in + * one corrected target byte and consumes fec->roots parity bytes. + */ + fec_for_each_buffer_rs_block(fio, n, i) { + block = fec_buffer_rs_block(v, fio, n, i); + res = fec_decode_rs8(v, fio, block, &par[offset], neras); + if (res < 0) { + dm_bufio_release(buf); + + r = res; + goto error; + } + + corrected += res; + fio->output[block_offset] = block[byte_index]; + + block_offset++; + if (block_offset >= 1 << v->data_dev_block_bits) + goto done; + + /* read the next block when we run out of parity bytes */ + offset += v->fec->roots; + if (offset >= 1 << v->data_dev_block_bits) { + dm_bufio_release(buf); + + par = fec_read_parity(v, rsb, block_offset, &offset, &buf); + if (unlikely(IS_ERR(par))) + return PTR_ERR(par); + } + } +done: + r = corrected; +error: + if (r < 0 && neras) + DMERR_LIMIT("%s: FEC %llu: failed to correct: %d", + v->data_dev->name, (unsigned long long)rsb, r); + else if (r > 0) { + DMWARN_LIMIT("%s: FEC %llu: corrected %d errors", + v->data_dev->name, (unsigned long long)rsb, r); + atomic_add_unless(&v->fec->corrected, 1, INT_MAX); + } + + return r; +} + +/* + * Locate data block erasures using verity hashes. + */ +static int fec_is_erasure(struct dm_verity *v, struct dm_verity_io *io, + u8 *want_digest, u8 *data) +{ + if (unlikely(verity_hash(v, verity_io_hash_desc(v, io), + data, 1 << v->data_dev_block_bits, + verity_io_real_digest(v, io)))) + return 0; + + return memcmp(verity_io_real_digest(v, io), want_digest, + v->digest_size) != 0; +} + +/* + * Read data blocks that are part of the RS block and deinterleave as much as + * fits into buffers. Check for erasure locations if @neras is non-NULL. + */ +static int fec_read_bufs(struct dm_verity *v, struct dm_verity_io *io, + u64 rsb, u64 target, unsigned block_offset, + int *neras) +{ + bool is_zero; + int i, j, target_index = -1; + struct dm_buffer *buf; + struct dm_bufio_client *bufio; + struct dm_verity_fec_io *fio = fec_io(io); + u64 block, ileaved; + u8 *bbuf, *rs_block; + u8 want_digest[v->digest_size]; + unsigned n, k; + + if (neras) + *neras = 0; + + /* + * read each of the rsn data blocks that are part of the RS block, and + * interleave contents to available bufs + */ + for (i = 0; i < v->fec->rsn; i++) { + ileaved = fec_interleave(v, rsb * v->fec->rsn + i); + + /* + * target is the data block we want to correct, target_index is + * the index of this block within the rsn RS blocks + */ + if (ileaved == target) + target_index = i; + + block = ileaved >> v->data_dev_block_bits; + bufio = v->fec->data_bufio; + + if (block >= v->data_blocks) { + block -= v->data_blocks; + + /* + * blocks outside the area were assumed to contain + * zeros when encoding data was generated + */ + if (unlikely(block >= v->fec->hash_blocks)) + continue; + + block += v->hash_start; + bufio = v->bufio; + } + + bbuf = dm_bufio_read(bufio, block, &buf); + if (unlikely(IS_ERR(bbuf))) { + DMWARN_LIMIT("%s: FEC %llu: read failed (%llu): %ld", + v->data_dev->name, + (unsigned long long)rsb, + (unsigned long long)block, PTR_ERR(bbuf)); + + /* assume the block is corrupted */ + if (neras && *neras <= v->fec->roots) + fio->erasures[(*neras)++] = i; + + continue; + } + + /* locate erasures if the block is on the data device */ + if (bufio == v->fec->data_bufio && + verity_hash_for_block(v, io, block, want_digest, + &is_zero) == 0) { + /* skip known zero blocks entirely */ + if (is_zero) + continue; + + /* + * skip if we have already found the theoretical + * maximum number (i.e. fec->roots) of erasures + */ + if (neras && *neras <= v->fec->roots && + fec_is_erasure(v, io, want_digest, bbuf)) + fio->erasures[(*neras)++] = i; + } + + /* + * deinterleave and copy the bytes that fit into bufs, + * starting from block_offset + */ + fec_for_each_buffer_rs_block(fio, n, j) { + k = fec_buffer_rs_index(n, j) + block_offset; + + if (k >= 1 << v->data_dev_block_bits) + goto done; + + rs_block = fec_buffer_rs_block(v, fio, n, j); + rs_block[i] = bbuf[k]; + } +done: + dm_bufio_release(buf); + } + + return target_index; +} + +/* + * Allocate RS control structure and FEC buffers from preallocated mempools, + * and attempt to allocate as many extra buffers as available. + */ +static int fec_alloc_bufs(struct dm_verity *v, struct dm_verity_fec_io *fio) +{ + unsigned n; + + if (!fio->rs) { + fio->rs = mempool_alloc(v->fec->rs_pool, 0); + if (unlikely(!fio->rs)) { + DMERR("failed to allocate RS"); + return -ENOMEM; + } + } + + fec_for_each_prealloc_buffer(n) { + if (fio->bufs[n]) + continue; + + fio->bufs[n] = mempool_alloc(v->fec->prealloc_pool, GFP_NOIO); + if (unlikely(!fio->bufs[n])) { + DMERR("failed to allocate FEC buffer"); + return -ENOMEM; + } + } + + /* try to allocate the maximum number of buffers */ + fec_for_each_extra_buffer(fio, n) { + if (fio->bufs[n]) + continue; + + fio->bufs[n] = mempool_alloc(v->fec->extra_pool, GFP_NOIO); + /* we can manage with even one buffer if necessary */ + if (unlikely(!fio->bufs[n])) + break; + } + fio->nbufs = n; + + if (!fio->output) { + fio->output = mempool_alloc(v->fec->output_pool, GFP_NOIO); + + if (!fio->output) { + DMERR("failed to allocate FEC page"); + return -ENOMEM; + } + } + + return 0; +} + +/* + * Initialize buffers and clear erasures. fec_read_bufs() assumes buffers are + * zeroed before deinterleaving. + */ +static void fec_init_bufs(struct dm_verity *v, struct dm_verity_fec_io *fio) +{ + unsigned n; + + fec_for_each_buffer(fio, n) + memset(fio->bufs[n], 0, v->fec->rsn << DM_VERITY_FEC_BUF_RS_BITS); + + memset(fio->erasures, 0, sizeof(fio->erasures)); +} + +/* + * Decode all RS blocks in a single data block and return the target block + * (indicated by @offset) in fio->output. If @use_erasures is non-zero, uses + * hashes to locate erasures. + */ +static int fec_decode_rsb(struct dm_verity *v, struct dm_verity_io *io, + struct dm_verity_fec_io *fio, u64 rsb, u64 offset, + bool use_erasures) +{ + int r, neras = 0; + unsigned pos; + + r = fec_alloc_bufs(v, fio); + if (unlikely(r < 0)) + return r; + + for (pos = 0; pos < 1 << v->data_dev_block_bits; ) { + fec_init_bufs(v, fio); + + r = fec_read_bufs(v, io, rsb, offset, pos, + use_erasures ? &neras : NULL); + if (unlikely(r < 0)) + return r; + + r = fec_decode_bufs(v, fio, rsb, r, pos, neras); + if (r < 0) + return r; + + pos += fio->nbufs << DM_VERITY_FEC_BUF_RS_BITS; + } + + /* Always re-validate the corrected block against the expected hash */ + r = verity_hash(v, verity_io_hash_desc(v, io), fio->output, + 1 << v->data_dev_block_bits, + verity_io_real_digest(v, io)); + if (unlikely(r < 0)) + return r; + + if (memcmp(verity_io_real_digest(v, io), verity_io_want_digest(v, io), + v->digest_size)) { + DMERR_LIMIT("%s: FEC %llu: failed to correct (%d erasures)", + v->data_dev->name, (unsigned long long)rsb, neras); + return -EILSEQ; + } + + return 0; +} + +static int fec_bv_copy(struct dm_verity *v, struct dm_verity_io *io, u8 *data, + size_t len) +{ + struct dm_verity_fec_io *fio = fec_io(io); + + memcpy(data, &fio->output[fio->output_pos], len); + fio->output_pos += len; + + return 0; +} + +/* + * Correct errors in a block. Copies corrected block to dest if non-NULL, + * otherwise to a bio_vec starting from iter. + */ +int verity_fec_decode(struct dm_verity *v, struct dm_verity_io *io, + enum verity_block_type type, sector_t block, u8 *dest, + struct bvec_iter *iter) +{ + int r; + struct dm_verity_fec_io *fio = fec_io(io); + u64 offset, res, rsb; + + if (!verity_fec_is_enabled(v)) + return -EOPNOTSUPP; + + if (fio->level >= DM_VERITY_FEC_MAX_RECURSION) { + DMWARN_LIMIT("%s: FEC: recursion too deep", v->data_dev->name); + return -EIO; + } + + fio->level++; + + if (type == DM_VERITY_BLOCK_TYPE_METADATA) + block += v->data_blocks; + + /* + * For RS(M, N), the continuous FEC data is divided into blocks of N + * bytes. Since block size may not be divisible by N, the last block + * is zero padded when decoding. + * + * Each byte of the block is covered by a different RS(M, N) code, + * and each code is interleaved over N blocks to make it less likely + * that bursty corruption will leave us in unrecoverable state. + */ + + offset = block << v->data_dev_block_bits; + res = div64_u64(offset, v->fec->rounds << v->data_dev_block_bits); + + /* + * The base RS block we can feed to the interleaver to find out all + * blocks required for decoding. + */ + rsb = offset - res * (v->fec->rounds << v->data_dev_block_bits); + + /* + * Locating erasures is slow, so attempt to recover the block without + * them first. Do a second attempt with erasures if the corruption is + * bad enough. + */ + r = fec_decode_rsb(v, io, fio, rsb, offset, false); + if (r < 0) { + r = fec_decode_rsb(v, io, fio, rsb, offset, true); + if (r < 0) + goto done; + } + + if (dest) + memcpy(dest, fio->output, 1 << v->data_dev_block_bits); + else if (iter) { + fio->output_pos = 0; + r = verity_for_bv_block(v, io, iter, fec_bv_copy); + } + +done: + fio->level--; + return r; +} + +/* + * Clean up per-bio data. + */ +void verity_fec_finish_io(struct dm_verity_io *io) +{ + unsigned n; + struct dm_verity_fec *f = io->v->fec; + struct dm_verity_fec_io *fio = fec_io(io); + + if (!verity_fec_is_enabled(io->v)) + return; + + mempool_free(fio->rs, f->rs_pool); + + fec_for_each_prealloc_buffer(n) + mempool_free(fio->bufs[n], f->prealloc_pool); + + fec_for_each_extra_buffer(fio, n) + mempool_free(fio->bufs[n], f->extra_pool); + + mempool_free(fio->output, f->output_pool); +} + +/* + * Initialize per-bio data. + */ +void verity_fec_init_io(struct dm_verity_io *io) +{ + struct dm_verity_fec_io *fio = fec_io(io); + + if (!verity_fec_is_enabled(io->v)) + return; + + fio->rs = NULL; + memset(fio->bufs, 0, sizeof(fio->bufs)); + fio->nbufs = 0; + fio->output = NULL; + fio->level = 0; +} + +/* + * Append feature arguments and values to the status table. + */ +unsigned verity_fec_status_table(struct dm_verity *v, unsigned sz, + char *result, unsigned maxlen) +{ + if (!verity_fec_is_enabled(v)) + return sz; + + DMEMIT(" " DM_VERITY_OPT_FEC_DEV " %s " + DM_VERITY_OPT_FEC_BLOCKS " %llu " + DM_VERITY_OPT_FEC_START " %llu " + DM_VERITY_OPT_FEC_ROOTS " %d", + v->fec->dev->name, + (unsigned long long)v->fec->blocks, + (unsigned long long)v->fec->start, + v->fec->roots); + + return sz; +} + +void verity_fec_dtr(struct dm_verity *v) +{ + struct dm_verity_fec *f = v->fec; + struct kobject *kobj = &f->kobj_holder.kobj; + + if (!verity_fec_is_enabled(v)) + goto out; + + mempool_destroy(f->rs_pool); + mempool_destroy(f->prealloc_pool); + mempool_destroy(f->extra_pool); + kmem_cache_destroy(f->cache); + + if (f->data_bufio) + dm_bufio_client_destroy(f->data_bufio); + if (f->bufio) + dm_bufio_client_destroy(f->bufio); + + if (f->dev) + dm_put_device(v->ti, f->dev); + + if (kobj->state_initialized) { + kobject_put(kobj); + wait_for_completion(dm_get_completion_from_kobject(kobj)); + } + +out: + kfree(f); + v->fec = NULL; +} + +static void *fec_rs_alloc(gfp_t gfp_mask, void *pool_data) +{ + struct dm_verity *v = (struct dm_verity *)pool_data; + + return init_rs(8, 0x11d, 0, 1, v->fec->roots); +} + +static void fec_rs_free(void *element, void *pool_data) +{ + struct rs_control *rs = (struct rs_control *)element; + + if (rs) + free_rs(rs); +} + +bool verity_is_fec_opt_arg(const char *arg_name) +{ + return (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_DEV) || + !strcasecmp(arg_name, DM_VERITY_OPT_FEC_BLOCKS) || + !strcasecmp(arg_name, DM_VERITY_OPT_FEC_START) || + !strcasecmp(arg_name, DM_VERITY_OPT_FEC_ROOTS)); +} + +int verity_fec_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v, + unsigned *argc, const char *arg_name) +{ + int r; + struct dm_target *ti = v->ti; + const char *arg_value; + unsigned long long num_ll; + unsigned char num_c; + char dummy; + + if (!*argc) { + ti->error = "FEC feature arguments require a value"; + return -EINVAL; + } + + arg_value = dm_shift_arg(as); + (*argc)--; + + if (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_DEV)) { + r = dm_get_device(ti, arg_value, FMODE_READ, &v->fec->dev); + if (r) { + ti->error = "FEC device lookup failed"; + return r; + } + + } else if (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_BLOCKS)) { + if (sscanf(arg_value, "%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 " DM_VERITY_OPT_FEC_BLOCKS; + return -EINVAL; + } + v->fec->blocks = num_ll; + + } else if (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_START)) { + if (sscanf(arg_value, "%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 " DM_VERITY_OPT_FEC_START; + return -EINVAL; + } + v->fec->start = num_ll; + + } else if (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_ROOTS)) { + if (sscanf(arg_value, "%hhu%c", &num_c, &dummy) != 1 || !num_c || + num_c < (DM_VERITY_FEC_RSM - DM_VERITY_FEC_MAX_RSN) || + num_c > (DM_VERITY_FEC_RSM - DM_VERITY_FEC_MIN_RSN)) { + ti->error = "Invalid " DM_VERITY_OPT_FEC_ROOTS; + return -EINVAL; + } + v->fec->roots = num_c; + + } else { + ti->error = "Unrecognized verity FEC feature request"; + return -EINVAL; + } + + return 0; +} + +static ssize_t corrected_show(struct kobject *kobj, struct kobj_attribute *attr, + char *buf) +{ + struct dm_verity_fec *f = container_of(kobj, struct dm_verity_fec, + kobj_holder.kobj); + + return sprintf(buf, "%d\n", atomic_read(&f->corrected)); +} + +static struct kobj_attribute attr_corrected = __ATTR_RO(corrected); + +static struct attribute *fec_attrs[] = { + &attr_corrected.attr, + NULL +}; + +static struct kobj_type fec_ktype = { + .sysfs_ops = &kobj_sysfs_ops, + .default_attrs = fec_attrs, + .release = dm_kobject_release +}; + +/* + * Allocate dm_verity_fec for v->fec. Must be called before verity_fec_ctr. + */ +int verity_fec_ctr_alloc(struct dm_verity *v) +{ + struct dm_verity_fec *f; + + f = kzalloc(sizeof(struct dm_verity_fec), GFP_KERNEL); + if (!f) { + v->ti->error = "Cannot allocate FEC structure"; + return -ENOMEM; + } + v->fec = f; + + return 0; +} + +/* + * Validate arguments and preallocate memory. Must be called after arguments + * have been parsed using verity_fec_parse_opt_args. + */ +int verity_fec_ctr(struct dm_verity *v) +{ + int r; + struct dm_verity_fec *f = v->fec; + struct dm_target *ti = v->ti; + struct mapped_device *md = dm_table_get_md(ti->table); + u64 hash_blocks; + + if (!verity_fec_is_enabled(v)) { + verity_fec_dtr(v); + return 0; + } + + /* Create a kobject and sysfs attributes */ + init_completion(&f->kobj_holder.completion); + + r = kobject_init_and_add(&f->kobj_holder.kobj, &fec_ktype, + &disk_to_dev(dm_disk(md))->kobj, "%s", "fec"); + if (r) { + ti->error = "Cannot create kobject"; + return r; + } + + /* + * FEC is computed over data blocks, possible metadata, and + * hash blocks. In other words, FEC covers total of fec_blocks + * blocks consisting of the following: + * + * data blocks | hash blocks | metadata (optional) + * + * We allow metadata after hash blocks to support a use case + * where all data is stored on the same device and FEC covers + * the entire area. + * + * If metadata is included, we require it to be available on the + * hash device after the hash blocks. + */ + + hash_blocks = v->hash_blocks - v->hash_start; + + /* + * Require matching block sizes for data and hash devices for + * simplicity. + */ + if (v->data_dev_block_bits != v->hash_dev_block_bits) { + ti->error = "Block sizes must match to use FEC"; + return -EINVAL; + } + + if (!f->roots) { + ti->error = "Missing " DM_VERITY_OPT_FEC_ROOTS; + return -EINVAL; + } + f->rsn = DM_VERITY_FEC_RSM - f->roots; + + if (!f->blocks) { + ti->error = "Missing " DM_VERITY_OPT_FEC_BLOCKS; + return -EINVAL; + } + + f->rounds = f->blocks; + if (sector_div(f->rounds, f->rsn)) + f->rounds++; + + /* + * Due to optional metadata, f->blocks can be larger than + * data_blocks and hash_blocks combined. + */ + if (f->blocks < v->data_blocks + hash_blocks || !f->rounds) { + ti->error = "Invalid " DM_VERITY_OPT_FEC_BLOCKS; + return -EINVAL; + } + + /* + * Metadata is accessed through the hash device, so we require + * it to be large enough. + */ + f->hash_blocks = f->blocks - v->data_blocks; + if (dm_bufio_get_device_size(v->bufio) < f->hash_blocks) { + ti->error = "Hash device is too small for " + DM_VERITY_OPT_FEC_BLOCKS; + return -E2BIG; + } + + f->bufio = dm_bufio_client_create(f->dev->bdev, + 1 << v->data_dev_block_bits, + 1, 0, NULL, NULL); + if (IS_ERR(f->bufio)) { + ti->error = "Cannot initialize FEC bufio client"; + return PTR_ERR(f->bufio); + } + + if (dm_bufio_get_device_size(f->bufio) < + ((f->start + f->rounds * f->roots) >> v->data_dev_block_bits)) { + ti->error = "FEC device is too small"; + return -E2BIG; + } + + f->data_bufio = dm_bufio_client_create(v->data_dev->bdev, + 1 << v->data_dev_block_bits, + 1, 0, NULL, NULL); + if (IS_ERR(f->data_bufio)) { + ti->error = "Cannot initialize FEC data bufio client"; + return PTR_ERR(f->data_bufio); + } + + if (dm_bufio_get_device_size(f->data_bufio) < v->data_blocks) { + ti->error = "Data device is too small"; + return -E2BIG; + } + + /* Preallocate an rs_control structure for each worker thread */ + f->rs_pool = mempool_create(num_online_cpus(), fec_rs_alloc, + fec_rs_free, (void *) v); + if (!f->rs_pool) { + ti->error = "Cannot allocate RS pool"; + return -ENOMEM; + } + + f->cache = kmem_cache_create("dm_verity_fec_buffers", + f->rsn << DM_VERITY_FEC_BUF_RS_BITS, + 0, 0, NULL); + if (!f->cache) { + ti->error = "Cannot create FEC buffer cache"; + return -ENOMEM; + } + + /* Preallocate DM_VERITY_FEC_BUF_PREALLOC buffers for each thread */ + f->prealloc_pool = mempool_create_slab_pool(num_online_cpus() * + DM_VERITY_FEC_BUF_PREALLOC, + f->cache); + if (!f->prealloc_pool) { + ti->error = "Cannot allocate FEC buffer prealloc pool"; + return -ENOMEM; + } + + f->extra_pool = mempool_create_slab_pool(0, f->cache); + if (!f->extra_pool) { + ti->error = "Cannot allocate FEC buffer extra pool"; + return -ENOMEM; + } + + /* Preallocate an output buffer for each thread */ + f->output_pool = mempool_create_kmalloc_pool(num_online_cpus(), + 1 << v->data_dev_block_bits); + if (!f->output_pool) { + ti->error = "Cannot allocate FEC output pool"; + return -ENOMEM; + } + + /* Reserve space for our per-bio data */ + ti->per_bio_data_size += sizeof(struct dm_verity_fec_io); + + return 0; +} diff --git a/drivers/md/dm-verity-fec.h b/drivers/md/dm-verity-fec.h new file mode 100644 index 000000000000..b8e21cef3ad1 --- /dev/null +++ b/drivers/md/dm-verity-fec.h @@ -0,0 +1,159 @@ +/* + * Copyright (C) 2015 Google, Inc. + * + * Author: Sami Tolvanen <samitolvanen@google.com> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the Free + * Software Foundation; either version 2 of the License, or (at your option) + * any later version. + */ + +#ifndef DM_VERITY_FEC_H +#define DM_VERITY_FEC_H + +#include "dm.h" +#include "dm-verity.h" +#include <linux/rslib.h> + +/* Reed-Solomon(M, N) parameters */ +#define DM_VERITY_FEC_RSM 255 +#define DM_VERITY_FEC_MAX_RSN 253 +#define DM_VERITY_FEC_MIN_RSN 231 /* ~10% space overhead */ + +/* buffers for deinterleaving and decoding */ +#define DM_VERITY_FEC_BUF_PREALLOC 1 /* buffers to preallocate */ +#define DM_VERITY_FEC_BUF_RS_BITS 4 /* 1 << RS blocks per buffer */ +/* we need buffers for at most 1 << block size RS blocks */ +#define DM_VERITY_FEC_BUF_MAX \ + (1 << (PAGE_SHIFT - DM_VERITY_FEC_BUF_RS_BITS)) + +/* maximum recursion level for verity_fec_decode */ +#define DM_VERITY_FEC_MAX_RECURSION 4 + +#define DM_VERITY_OPT_FEC_DEV "use_fec_from_device" +#define DM_VERITY_OPT_FEC_BLOCKS "fec_blocks" +#define DM_VERITY_OPT_FEC_START "fec_start" +#define DM_VERITY_OPT_FEC_ROOTS "fec_roots" + +/* configuration */ +struct dm_verity_fec { + struct dm_dev *dev; /* parity data device */ + struct dm_bufio_client *data_bufio; /* for data dev access */ + struct dm_bufio_client *bufio; /* for parity data access */ + sector_t start; /* parity data start in blocks */ + sector_t blocks; /* number of blocks covered */ + sector_t rounds; /* number of interleaving rounds */ + sector_t hash_blocks; /* blocks covered after v->hash_start */ + unsigned char roots; /* number of parity bytes, M-N of RS(M, N) */ + unsigned char rsn; /* N of RS(M, N) */ + mempool_t *rs_pool; /* mempool for fio->rs */ + mempool_t *prealloc_pool; /* mempool for preallocated buffers */ + mempool_t *extra_pool; /* mempool for extra buffers */ + mempool_t *output_pool; /* mempool for output */ + struct kmem_cache *cache; /* cache for buffers */ + atomic_t corrected; /* corrected errors */ + struct dm_kobject_holder kobj_holder; /* for sysfs attributes */ +}; + +/* per-bio data */ +struct dm_verity_fec_io { + struct rs_control *rs; /* Reed-Solomon state */ + int erasures[DM_VERITY_FEC_MAX_RSN]; /* erasures for decode_rs8 */ + u8 *bufs[DM_VERITY_FEC_BUF_MAX]; /* bufs for deinterleaving */ + unsigned nbufs; /* number of buffers allocated */ + u8 *output; /* buffer for corrected output */ + size_t output_pos; + unsigned level; /* recursion level */ +}; + +#ifdef CONFIG_DM_VERITY_FEC + +/* each feature parameter requires a value */ +#define DM_VERITY_OPTS_FEC 8 + +extern bool verity_fec_is_enabled(struct dm_verity *v); + +extern int verity_fec_decode(struct dm_verity *v, struct dm_verity_io *io, + enum verity_block_type type, sector_t block, + u8 *dest, struct bvec_iter *iter); + +extern unsigned verity_fec_status_table(struct dm_verity *v, unsigned sz, + char *result, unsigned maxlen); + +extern void verity_fec_finish_io(struct dm_verity_io *io); +extern void verity_fec_init_io(struct dm_verity_io *io); + +extern bool verity_is_fec_opt_arg(const char *arg_name); +extern int verity_fec_parse_opt_args(struct dm_arg_set *as, + struct dm_verity *v, unsigned *argc, + const char *arg_name); + +extern void verity_fec_dtr(struct dm_verity *v); + +extern int verity_fec_ctr_alloc(struct dm_verity *v); +extern int verity_fec_ctr(struct dm_verity *v); + +#else /* !CONFIG_DM_VERITY_FEC */ + +#define DM_VERITY_OPTS_FEC 0 + +static inline bool verity_fec_is_enabled(struct dm_verity *v) +{ + return false; +} + +static inline int verity_fec_decode(struct dm_verity *v, + struct dm_verity_io *io, + enum verity_block_type type, + sector_t block, u8 *dest, + struct bvec_iter *iter) +{ + return -EOPNOTSUPP; +} + +static inline unsigned verity_fec_status_table(struct dm_verity *v, + unsigned sz, char *result, + unsigned maxlen) +{ + return sz; +} + +static inline void verity_fec_finish_io(struct dm_verity_io *io) +{ +} + +static inline void verity_fec_init_io(struct dm_verity_io *io) +{ +} + +static inline bool verity_is_fec_opt_arg(const char *arg_name) +{ + return false; +} + +static inline int verity_fec_parse_opt_args(struct dm_arg_set *as, + struct dm_verity *v, + unsigned *argc, + const char *arg_name) +{ + return -EINVAL; +} + +static inline void verity_fec_dtr(struct dm_verity *v) +{ +} + +static inline int verity_fec_ctr_alloc(struct dm_verity *v) +{ + return 0; +} + +static inline int verity_fec_ctr(struct dm_verity *v) +{ + return 0; +} + +#endif /* CONFIG_DM_VERITY_FEC */ + +#endif /* DM_VERITY_FEC_H */ diff --git a/drivers/md/dm-verity.c b/drivers/md/dm-verity-target.c index ccf41886ebcf..c7e97cf6e7fb 100644 --- a/drivers/md/dm-verity.c +++ b/drivers/md/dm-verity-target.c @@ -14,12 +14,11 @@ * access behavior. */ -#include "dm-bufio.h" +#include "dm-verity.h" +#include "dm-verity-fec.h" #include <linux/module.h> -#include <linux/device-mapper.h> #include <linux/reboot.h> -#include <crypto/hash.h> #define DM_MSG_PREFIX "verity" @@ -28,83 +27,18 @@ #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" +#define DM_VERITY_OPT_IGN_ZEROES "ignore_zero_blocks" + +#define DM_VERITY_OPTS_MAX (2 + DM_VERITY_OPTS_FEC) 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 */ - - 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; @@ -112,21 +46,6 @@ struct dm_verity_prefetch_work { 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. @@ -173,6 +92,84 @@ static sector_t verity_position_at_level(struct dm_verity *v, sector_t block, return block >> (level * v->hash_per_block_bits); } +/* + * Wrapper for crypto_shash_init, which handles verity salting. + */ +static int verity_hash_init(struct dm_verity *v, struct shash_desc *desc) +{ + int r; + + desc->tfm = v->tfm; + desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; + + r = crypto_shash_init(desc); + + if (unlikely(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 (unlikely(r < 0)) { + DMERR("crypto_shash_update failed: %d", r); + return r; + } + } + + return 0; +} + +static int verity_hash_update(struct dm_verity *v, struct shash_desc *desc, + const u8 *data, size_t len) +{ + int r = crypto_shash_update(desc, data, len); + + if (unlikely(r < 0)) + DMERR("crypto_shash_update failed: %d", r); + + return r; +} + +static int verity_hash_final(struct dm_verity *v, struct shash_desc *desc, + u8 *digest) +{ + int r; + + if (unlikely(!v->version)) { + r = crypto_shash_update(desc, v->salt, v->salt_size); + + if (r < 0) { + DMERR("crypto_shash_update failed: %d", r); + return r; + } + } + + r = crypto_shash_final(desc, digest); + + if (unlikely(r < 0)) + DMERR("crypto_shash_final failed: %d", r); + + return r; +} + +int verity_hash(struct dm_verity *v, struct shash_desc *desc, + const u8 *data, size_t len, u8 *digest) +{ + int r; + + r = verity_hash_init(v, desc); + if (unlikely(r < 0)) + return r; + + r = verity_hash_update(v, desc, data, len); + if (unlikely(r < 0)) + return r; + + return verity_hash_final(v, desc, digest); +} + static void verity_hash_at_level(struct dm_verity *v, sector_t block, int level, sector_t *hash_block, unsigned *offset) { @@ -246,17 +243,17 @@ out: * 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). + * On successful return, verity_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 level). * * 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). + * against current value of verity_io_want_digest(v, io). */ -static int verity_verify_level(struct dm_verity_io *io, sector_t block, - int level, bool skip_unverified) +static int verity_verify_level(struct dm_verity *v, struct dm_verity_io *io, + sector_t block, int level, bool skip_unverified, + u8 *want_digest) { - struct dm_verity *v = io->v; struct dm_buffer *buf; struct buffer_aux *aux; u8 *data; @@ -273,72 +270,128 @@ static int verity_verify_level(struct dm_verity_io *io, sector_t block, 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); + r = verity_hash(v, verity_io_hash_desc(v, io), + data, 1 << v->hash_dev_block_bits, + verity_io_real_digest(v, io)); + if (unlikely(r < 0)) 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); + if (likely(memcmp(verity_io_real_digest(v, io), want_digest, + v->digest_size) == 0)) + aux->hash_verified = 1; + else if (verity_fec_decode(v, io, + DM_VERITY_BLOCK_TYPE_METADATA, + hash_block, data, NULL) == 0) + aux->hash_verified = 1; + else if (verity_handle_err(v, + DM_VERITY_BLOCK_TYPE_METADATA, + hash_block)) { + r = -EIO; 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; - } - } + data += offset; + memcpy(want_digest, data, v->digest_size); + r = 0; - 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; +release_ret_r: + dm_bufio_release(buf); + return r; +} + +/* + * Find a hash for a given block, write it to digest and verify the integrity + * of the hash tree if necessary. + */ +int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io, + sector_t block, u8 *digest, bool *is_zero) +{ + int r = 0, i; + + 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 1 and we fall back to whole + * chain verification. + */ + r = verity_verify_level(v, io, block, 0, true, digest); + if (likely(r <= 0)) + goto out; } - data += offset; + memcpy(digest, v->root_digest, v->digest_size); + + for (i = v->levels - 1; i >= 0; i--) { + r = verity_verify_level(v, io, block, i, false, digest); + if (unlikely(r)) + goto out; + } +out: + if (!r && v->zero_digest) + *is_zero = !memcmp(v->zero_digest, digest, v->digest_size); + else + *is_zero = false; - memcpy(io_want_digest(v, io), data, v->digest_size); + return r; +} + +/* + * Calls function process for 1 << v->data_dev_block_bits bytes in the bio_vec + * starting from iter. + */ +int verity_for_bv_block(struct dm_verity *v, struct dm_verity_io *io, + struct bvec_iter *iter, + int (*process)(struct dm_verity *v, + struct dm_verity_io *io, u8 *data, + size_t len)) +{ + unsigned todo = 1 << v->data_dev_block_bits; + struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_bio_data_size); + + do { + int r; + u8 *page; + unsigned len; + struct bio_vec bv = bio_iter_iovec(bio, *iter); + + page = kmap_atomic(bv.bv_page); + len = bv.bv_len; + + if (likely(len >= todo)) + len = todo; + + r = process(v, io, page + bv.bv_offset, len); + kunmap_atomic(page); + + if (r < 0) + return r; + + bio_advance_iter(bio, iter, len); + todo -= len; + } while (todo); - dm_bufio_release(buf); return 0; +} -release_ret_r: - dm_bufio_release(buf); +static int verity_bv_hash_update(struct dm_verity *v, struct dm_verity_io *io, + u8 *data, size_t len) +{ + return verity_hash_update(v, verity_io_hash_desc(v, io), data, len); +} - return r; +static int verity_bv_zero(struct dm_verity *v, struct dm_verity_io *io, + u8 *data, size_t len) +{ + memset(data, 0, len); + return 0; } /* @@ -346,99 +399,56 @@ release_ret_r: */ static int verity_verify_io(struct dm_verity_io *io) { + bool is_zero; struct dm_verity *v = io->v; - struct bio *bio = dm_bio_from_per_bio_data(io, - v->ti->per_bio_data_size); + struct bvec_iter start; unsigned b; - int i; for (b = 0; b < io->n_blocks; b++) { - struct shash_desc *desc; - u8 *result; int r; - unsigned todo; + struct shash_desc *desc = verity_io_hash_desc(v, io); - if (likely(v->levels)) { + r = verity_hash_for_block(v, io, io->block + b, + verity_io_want_digest(v, io), + &is_zero); + if (unlikely(r < 0)) + return r; + + if (is_zero) { /* - * 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. + * If we expect a zero block, don't validate, just + * return zeros. */ - int r = verity_verify_level(io, io->block + b, 0, true); - if (likely(!r)) - goto test_block_hash; - if (r < 0) + r = verity_for_bv_block(v, io, &io->iter, + verity_bv_zero); + if (unlikely(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; + continue; } -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); + r = verity_hash_init(v, desc); + if (unlikely(r < 0)) 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; - } - } + start = io->iter; + r = verity_for_bv_block(v, io, &io->iter, verity_bv_hash_update); + if (unlikely(r < 0)) + return r; - result = io_real_digest(v, io); - r = crypto_shash_final(desc, result); - if (r < 0) { - DMERR("crypto_shash_final failed: %d", r); + r = verity_hash_final(v, desc, verity_io_real_digest(v, io)); + if (unlikely(r < 0)) 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; - } + + if (likely(memcmp(verity_io_real_digest(v, io), + verity_io_want_digest(v, io), v->digest_size) == 0)) + continue; + else if (verity_fec_decode(v, io, DM_VERITY_BLOCK_TYPE_DATA, + io->block + b, NULL, &start) == 0) + continue; + else if (verity_handle_err(v, DM_VERITY_BLOCK_TYPE_DATA, + io->block + b)) + return -EIO; } return 0; @@ -453,9 +463,10 @@ static void verity_finish_io(struct dm_verity_io *io, int error) 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->bi_error = error; + verity_fec_finish_io(io); + bio_endio(bio); } @@ -470,7 +481,7 @@ static void verity_end_io(struct bio *bio) { struct dm_verity_io *io = bio->bi_private; - if (bio->bi_error) { + if (bio->bi_error && !verity_fec_is_enabled(io->v)) { verity_finish_io(io, bio->bi_error); return; } @@ -490,6 +501,7 @@ static void verity_prefetch_io(struct work_struct *work) container_of(work, struct dm_verity_prefetch_work, work); struct dm_verity *v = pw->v; int i; + sector_t prefetch_size; for (i = v->levels - 2; i >= 0; i--) { sector_t hash_block_start; @@ -512,8 +524,14 @@ static void verity_prefetch_io(struct work_struct *work) hash_block_end = v->hash_blocks - 1; } no_prefetch_cluster: + // for emmc, it is more efficient to send bigger read + prefetch_size = max((sector_t)CONFIG_DM_VERITY_HASH_PREFETCH_MIN_SIZE, + hash_block_end - hash_block_start + 1); + if ((hash_block_start + prefetch_size) >= (v->hash_start + v->hash_blocks)) { + prefetch_size = hash_block_end - hash_block_start + 1; + } dm_bufio_prefetch(v->bufio, hash_block_start, - hash_block_end - hash_block_start + 1); + prefetch_size); } kfree(pw); @@ -540,7 +558,7 @@ static void verity_submit_prefetch(struct dm_verity *v, struct dm_verity_io *io) * 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) +int verity_map(struct dm_target *ti, struct bio *bio) { struct dm_verity *v = ti->private; struct dm_verity_io *io; @@ -566,7 +584,6 @@ static int verity_map(struct dm_target *ti, struct bio *bio) 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; @@ -574,20 +591,24 @@ static int verity_map(struct dm_target *ti, struct bio *bio) bio->bi_private = io; io->iter = bio->bi_iter; + verity_fec_init_io(io); + verity_submit_prefetch(v, io); generic_make_request(bio); return DM_MAPIO_SUBMITTED; } +EXPORT_SYMBOL_GPL(verity_map); /* * Status: V (valid) or C (corruption found) */ -static void verity_status(struct dm_target *ti, status_type_t type, +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 args = 0; unsigned sz = 0; unsigned x; @@ -614,8 +635,17 @@ static void verity_status(struct dm_target *ti, status_type_t type, else for (x = 0; x < v->salt_size; x++) DMEMIT("%02x", v->salt[x]); + if (v->mode != DM_VERITY_MODE_EIO) + args++; + if (verity_fec_is_enabled(v)) + args += DM_VERITY_OPTS_FEC; + if (v->zero_digest) + args++; + if (!args) + return; + DMEMIT(" %u", args); if (v->mode != DM_VERITY_MODE_EIO) { - DMEMIT(" 1 "); + DMEMIT(" "); switch (v->mode) { case DM_VERITY_MODE_LOGGING: DMEMIT(DM_VERITY_OPT_LOGGING); @@ -627,11 +657,15 @@ static void verity_status(struct dm_target *ti, status_type_t type, BUG(); } } + if (v->zero_digest) + DMEMIT(" " DM_VERITY_OPT_IGN_ZEROES); + sz = verity_fec_status_table(v, sz, result, maxlen); break; } } +EXPORT_SYMBOL_GPL(verity_status); -static int verity_prepare_ioctl(struct dm_target *ti, +int verity_prepare_ioctl(struct dm_target *ti, struct block_device **bdev, fmode_t *mode) { struct dm_verity *v = ti->private; @@ -643,16 +677,18 @@ static int verity_prepare_ioctl(struct dm_target *ti, return 1; return 0; } +EXPORT_SYMBOL_GPL(verity_prepare_ioctl); -static int verity_iterate_devices(struct dm_target *ti, +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); } +EXPORT_SYMBOL_GPL(verity_iterate_devices); -static void verity_io_hints(struct dm_target *ti, struct queue_limits *limits) +void verity_io_hints(struct dm_target *ti, struct queue_limits *limits) { struct dm_verity *v = ti->private; @@ -664,8 +700,9 @@ static void verity_io_hints(struct dm_target *ti, struct queue_limits *limits) blk_limits_io_min(limits, limits->logical_block_size); } +EXPORT_SYMBOL_GPL(verity_io_hints); -static void verity_dtr(struct dm_target *ti) +void verity_dtr(struct dm_target *ti) { struct dm_verity *v = ti->private; @@ -677,6 +714,7 @@ static void verity_dtr(struct dm_target *ti) kfree(v->salt); kfree(v->root_digest); + kfree(v->zero_digest); if (v->tfm) crypto_free_shash(v->tfm); @@ -689,8 +727,94 @@ static void verity_dtr(struct dm_target *ti) if (v->data_dev) dm_put_device(ti, v->data_dev); + verity_fec_dtr(v); + kfree(v); } +EXPORT_SYMBOL_GPL(verity_dtr); + +static int verity_alloc_zero_digest(struct dm_verity *v) +{ + int r = -ENOMEM; + struct shash_desc *desc; + u8 *zero_data; + + v->zero_digest = kmalloc(v->digest_size, GFP_KERNEL); + + if (!v->zero_digest) + return r; + + desc = kmalloc(v->shash_descsize, GFP_KERNEL); + + if (!desc) + return r; /* verity_dtr will free zero_digest */ + + zero_data = kzalloc(1 << v->data_dev_block_bits, GFP_KERNEL); + + if (!zero_data) + goto out; + + r = verity_hash(v, desc, zero_data, 1 << v->data_dev_block_bits, + v->zero_digest); + +out: + kfree(desc); + kfree(zero_data); + + return r; +} + +static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v) +{ + int r; + unsigned argc; + struct dm_target *ti = v->ti; + const char *arg_name; + + static struct dm_arg _args[] = { + {0, DM_VERITY_OPTS_MAX, "Invalid number of feature args"}, + }; + + r = dm_read_arg_group(_args, as, &argc, &ti->error); + if (r) + return -EINVAL; + + if (!argc) + return 0; + + do { + arg_name = dm_shift_arg(as); + argc--; + + if (!strcasecmp(arg_name, DM_VERITY_OPT_LOGGING)) { + v->mode = DM_VERITY_MODE_LOGGING; + continue; + + } else if (!strcasecmp(arg_name, DM_VERITY_OPT_RESTART)) { + v->mode = DM_VERITY_MODE_RESTART; + continue; + + } else if (!strcasecmp(arg_name, DM_VERITY_OPT_IGN_ZEROES)) { + r = verity_alloc_zero_digest(v); + if (r) { + ti->error = "Cannot allocate zero digest"; + return r; + } + continue; + + } else if (verity_is_fec_opt_arg(arg_name)) { + r = verity_fec_parse_opt_args(as, v, &argc, arg_name); + if (r) + return r; + continue; + } + + ti->error = "Unrecognized verity feature request"; + return -EINVAL; + } while (argc && !r); + + return r; +} /* * Target parameters: @@ -706,22 +830,17 @@ static void verity_dtr(struct dm_target *ti) * <digest> * <salt> Hex string or "-" if no salt. */ -static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv) +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 int num; 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"; @@ -730,6 +849,10 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv) ti->private = v; v->ti = ti; + r = verity_fec_ctr_alloc(v); + if (r) + goto bad; + if ((dm_table_get_mode(ti->table) & ~FMODE_READ)) { ti->error = "Device must be readonly"; r = -EINVAL; @@ -866,29 +989,9 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv) as.argc = argc; as.argv = argv; - r = dm_read_arg_group(_args, &as, &opt_params, &ti->error); - if (r) + r = verity_parse_opt_args(&as, v); + if (r < 0) 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 = @@ -938,8 +1041,6 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv) 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)); - /* 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) { @@ -948,6 +1049,16 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv) goto bad; } + ti->per_bio_data_size = sizeof(struct dm_verity_io) + + v->shash_descsize + v->digest_size * 2; + + r = verity_fec_ctr(v); + if (r) + goto bad; + + ti->per_bio_data_size = roundup(ti->per_bio_data_size, + __alignof__(struct dm_verity_io)); + return 0; bad: @@ -955,10 +1066,11 @@ bad: return r; } +EXPORT_SYMBOL_GPL(verity_ctr); static struct target_type verity_target = { .name = "verity", - .version = {1, 2, 0}, + .version = {1, 3, 0}, .module = THIS_MODULE, .ctr = verity_ctr, .dtr = verity_dtr, diff --git a/drivers/md/dm-verity.h b/drivers/md/dm-verity.h new file mode 100644 index 000000000000..75effca400a3 --- /dev/null +++ b/drivers/md/dm-verity.h @@ -0,0 +1,139 @@ +/* + * Copyright (C) 2012 Red Hat, Inc. + * Copyright (C) 2015 Google, 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. + */ + +#ifndef DM_VERITY_H +#define DM_VERITY_H + +#include "dm-bufio.h" +#include <linux/device-mapper.h> +#include <crypto/hash.h> + +#define DM_VERITY_MAX_LEVELS 63 + +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_fec; + +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 */ + u8 *zero_digest; /* digest for a zero block */ + 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 */ + + 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_fec *fec; /* forward error correction */ +}; + +struct dm_verity_io { + struct dm_verity *v; + + /* original value of bio->bi_end_io */ + bio_end_io_t *orig_bi_end_io; + + 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: verity_io_hash_desc(), verity_io_real_digest() + * and verity_io_want_digest(). + */ +}; + +static inline struct shash_desc *verity_io_hash_desc(struct dm_verity *v, + struct dm_verity_io *io) +{ + return (struct shash_desc *)(io + 1); +} + +static inline u8 *verity_io_real_digest(struct dm_verity *v, + struct dm_verity_io *io) +{ + return (u8 *)(io + 1) + v->shash_descsize; +} + +static inline u8 *verity_io_want_digest(struct dm_verity *v, + struct dm_verity_io *io) +{ + return (u8 *)(io + 1) + v->shash_descsize + v->digest_size; +} + +static inline u8 *verity_io_digest_end(struct dm_verity *v, + struct dm_verity_io *io) +{ + return verity_io_want_digest(v, io) + v->digest_size; +} + +extern int verity_for_bv_block(struct dm_verity *v, struct dm_verity_io *io, + struct bvec_iter *iter, + int (*process)(struct dm_verity *v, + struct dm_verity_io *io, + u8 *data, size_t len)); + +extern int verity_hash(struct dm_verity *v, struct shash_desc *desc, + const u8 *data, size_t len, u8 *digest); + +extern int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io, + sector_t block, u8 *digest, bool *is_zero); + +extern void verity_status(struct dm_target *ti, status_type_t type, + unsigned status_flags, char *result, unsigned maxlen); +extern int verity_prepare_ioctl(struct dm_target *ti, + struct block_device **bdev, fmode_t *mode); +extern int verity_iterate_devices(struct dm_target *ti, + iterate_devices_callout_fn fn, void *data); +extern void verity_io_hints(struct dm_target *ti, struct queue_limits *limits); +extern void verity_dtr(struct dm_target *ti); +extern int verity_ctr(struct dm_target *ti, unsigned argc, char **argv); +extern int verity_map(struct dm_target *ti, struct bio *bio); +#endif /* DM_VERITY_H */ |