| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Mikulas Patocka | 3380 | 48.47% | 11 | 14.67% |
| Sami Tolvanen | 1505 | 21.58% | 7 | 9.33% |
| Gilad Ben-Yossef | 410 | 5.88% | 3 | 4.00% |
| Nathan Huckleberry | 272 | 3.90% | 4 | 5.33% |
| Mike Snitzer | 246 | 3.53% | 10 | 13.33% |
| Tushar Sugandhi | 243 | 3.48% | 2 | 2.67% |
| Patrik Torstensson | 226 | 3.24% | 1 | 1.33% |
| JeongHyeon Lee | 153 | 2.19% | 3 | 4.00% |
| Matthias Kaehlcke | 139 | 1.99% | 2 | 2.67% |
| Jaskaran Khurana | 135 | 1.94% | 1 | 1.33% |
| xianrong.zhou | 70 | 1.00% | 1 | 1.33% |
| Christoph Hellwig | 49 | 0.70% | 9 | 12.00% |
| Akilesh Kailash | 33 | 0.47% | 1 | 1.33% |
| hyeongseok.kim | 28 | 0.40% | 1 | 1.33% |
| Eric Biggers | 23 | 0.33% | 3 | 4.00% |
| Heinz Mauelshagen | 23 | 0.33% | 3 | 4.00% |
| Kent Overstreet | 16 | 0.23% | 3 | 4.00% |
| Jun'ichi Nomura | 5 | 0.07% | 1 | 1.33% |
| Sarthak Kukreti | 5 | 0.07% | 1 | 1.33% |
| Alasdair G. Kergon | 3 | 0.04% | 1 | 1.33% |
| Kees Cook | 2 | 0.03% | 1 | 1.33% |
| Linus Torvalds | 2 | 0.03% | 1 | 1.33% |
| Milan Broz | 2 | 0.03% | 2 | 2.67% |
| Thomas Gleixner | 2 | 0.03% | 1 | 1.33% |
| Wei Yongjun | 1 | 0.01% | 1 | 1.33% |
| Mark Rutland | 1 | 0.01% | 1 | 1.33% |
| Total | 6974 | 75 |
// SPDX-License-Identifier: GPL-2.0-only /* * Copyright (C) 2012 Red Hat, Inc. * * Author: Mikulas Patocka <mpatocka@redhat.com> * * Based on Chromium dm-verity driver (C) 2011 The Chromium OS Authors * * In the file "/sys/module/dm_verity/parameters/prefetch_cluster" you can set * default prefetch value. Data are read in "prefetch_cluster" chunks from the * hash device. Setting this greatly improves performance when data and hash * are on the same disk on different partitions on devices with poor random * access behavior. */ #include "dm-verity.h" #include "dm-verity-fec.h" #include "dm-verity-verify-sig.h" #include <linux/module.h> #include <linux/reboot.h> #include <linux/scatterlist.h> #include <linux/string.h> #include <linux/jump_label.h> #define DM_MSG_PREFIX "verity" #define DM_VERITY_ENV_LENGTH 42 #define DM_VERITY_ENV_VAR_NAME "DM_VERITY_ERR_BLOCK_NR" #define DM_VERITY_DEFAULT_PREFETCH_SIZE 262144 #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_PANIC "panic_on_corruption" #define DM_VERITY_OPT_IGN_ZEROES "ignore_zero_blocks" #define DM_VERITY_OPT_AT_MOST_ONCE "check_at_most_once" #define DM_VERITY_OPT_TASKLET_VERIFY "try_verify_in_tasklet" #define DM_VERITY_OPTS_MAX (4 + DM_VERITY_OPTS_FEC + \ DM_VERITY_ROOT_HASH_VERIFICATION_OPTS) static unsigned int dm_verity_prefetch_cluster = DM_VERITY_DEFAULT_PREFETCH_SIZE; module_param_named(prefetch_cluster, dm_verity_prefetch_cluster, uint, 0644); static DEFINE_STATIC_KEY_FALSE(use_tasklet_enabled); struct dm_verity_prefetch_work { struct work_struct work; struct dm_verity *v; sector_t block; unsigned int n_blocks; }; /* * Auxiliary structure appended to each dm-bufio buffer. If the value * hash_verified is nonzero, hash of the block has been verified. * * The variable hash_verified is set to 0 when allocating the buffer, then * it can be changed to 1 and it is never reset to 0 again. * * There is no lock around this value, a race condition can at worst cause * that multiple processes verify the hash of the same buffer simultaneously * and write 1 to hash_verified simultaneously. * This condition is harmless, so we don't need locking. */ struct buffer_aux { int hash_verified; }; /* * Initialize struct buffer_aux for a freshly created buffer. */ static void dm_bufio_alloc_callback(struct dm_buffer *buf) { struct buffer_aux *aux = dm_bufio_get_aux_data(buf); aux->hash_verified = 0; } /* * Translate input sector number to the sector number on the target device. */ static sector_t verity_map_sector(struct dm_verity *v, sector_t bi_sector) { return v->data_start + dm_target_offset(v->ti, bi_sector); } /* * Return hash position of a specified block at a specified tree level * (0 is the lowest level). * The lowest "hash_per_block_bits"-bits of the result denote hash position * inside a hash block. The remaining bits denote location of the hash block. */ static sector_t verity_position_at_level(struct dm_verity *v, sector_t block, int level) { return block >> (level * v->hash_per_block_bits); } static int verity_hash_update(struct dm_verity *v, struct ahash_request *req, const u8 *data, size_t len, struct crypto_wait *wait) { struct scatterlist sg; if (likely(!is_vmalloc_addr(data))) { sg_init_one(&sg, data, len); ahash_request_set_crypt(req, &sg, NULL, len); return crypto_wait_req(crypto_ahash_update(req), wait); } do { int r; size_t this_step = min_t(size_t, len, PAGE_SIZE - offset_in_page(data)); flush_kernel_vmap_range((void *)data, this_step); sg_init_table(&sg, 1); sg_set_page(&sg, vmalloc_to_page(data), this_step, offset_in_page(data)); ahash_request_set_crypt(req, &sg, NULL, this_step); r = crypto_wait_req(crypto_ahash_update(req), wait); if (unlikely(r)) return r; data += this_step; len -= this_step; } while (len); return 0; } /* * Wrapper for crypto_ahash_init, which handles verity salting. */ static int verity_hash_init(struct dm_verity *v, struct ahash_request *req, struct crypto_wait *wait) { int r; ahash_request_set_tfm(req, v->tfm); ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP | CRYPTO_TFM_REQ_MAY_BACKLOG, crypto_req_done, (void *)wait); crypto_init_wait(wait); r = crypto_wait_req(crypto_ahash_init(req), wait); if (unlikely(r < 0)) { DMERR("crypto_ahash_init failed: %d", r); return r; } if (likely(v->salt_size && (v->version >= 1))) r = verity_hash_update(v, req, v->salt, v->salt_size, wait); return r; } static int verity_hash_final(struct dm_verity *v, struct ahash_request *req, u8 *digest, struct crypto_wait *wait) { int r; if (unlikely(v->salt_size && (!v->version))) { r = verity_hash_update(v, req, v->salt, v->salt_size, wait); if (r < 0) { DMERR("%s failed updating salt: %d", __func__, r); goto out; } } ahash_request_set_crypt(req, NULL, digest, 0); r = crypto_wait_req(crypto_ahash_final(req), wait); out: return r; } int verity_hash(struct dm_verity *v, struct ahash_request *req, const u8 *data, size_t len, u8 *digest) { int r; struct crypto_wait wait; r = verity_hash_init(v, req, &wait); if (unlikely(r < 0)) goto out; r = verity_hash_update(v, req, data, len, &wait); if (unlikely(r < 0)) goto out; r = verity_hash_final(v, req, digest, &wait); out: return r; } static void verity_hash_at_level(struct dm_verity *v, sector_t block, int level, sector_t *hash_block, unsigned int *offset) { sector_t position = verity_position_at_level(v, block, level); unsigned int idx; *hash_block = v->hash_level_block[level] + (position >> v->hash_per_block_bits); if (!offset) return; idx = position & ((1 << v->hash_per_block_bits) - 1); if (!v->version) *offset = idx * v->digest_size; else *offset = idx << (v->hash_dev_block_bits - v->hash_per_block_bits); } /* * Handle verification errors. */ static int verity_handle_err(struct dm_verity *v, enum verity_block_type type, unsigned long long block) { char verity_env[DM_VERITY_ENV_LENGTH]; char *envp[] = { verity_env, NULL }; const char *type_str = ""; struct mapped_device *md = dm_table_get_md(v->ti->table); /* Corruption should be visible in device status in all modes */ v->hash_failed = true; if (v->corrupted_errs >= DM_VERITY_MAX_CORRUPTED_ERRS) goto out; v->corrupted_errs++; switch (type) { case DM_VERITY_BLOCK_TYPE_DATA: type_str = "data"; break; case DM_VERITY_BLOCK_TYPE_METADATA: type_str = "metadata"; break; default: BUG(); } DMERR_LIMIT("%s: %s block %llu is corrupted", v->data_dev->name, type_str, block); if (v->corrupted_errs == DM_VERITY_MAX_CORRUPTED_ERRS) DMERR("%s: reached maximum errors", v->data_dev->name); snprintf(verity_env, DM_VERITY_ENV_LENGTH, "%s=%d,%llu", DM_VERITY_ENV_VAR_NAME, type, block); kobject_uevent_env(&disk_to_dev(dm_disk(md))->kobj, KOBJ_CHANGE, envp); out: if (v->mode == DM_VERITY_MODE_LOGGING) return 0; if (v->mode == DM_VERITY_MODE_RESTART) kernel_restart("dm-verity device corrupted"); if (v->mode == DM_VERITY_MODE_PANIC) panic("dm-verity device corrupted"); return 1; } /* * Verify hash of a metadata block pertaining to the specified data block * ("block" argument) at a specified level ("level" argument). * * On successful return, 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 verity_io_want_digest(v, io). */ 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_buffer *buf; struct buffer_aux *aux; u8 *data; int r; sector_t hash_block; unsigned int offset; verity_hash_at_level(v, block, level, &hash_block, &offset); if (static_branch_unlikely(&use_tasklet_enabled) && io->in_tasklet) { data = dm_bufio_get(v->bufio, hash_block, &buf); if (data == NULL) { /* * In tasklet and the hash was not in the bufio cache. * Return early and resume execution from a work-queue * to read the hash from disk. */ return -EAGAIN; } } else data = dm_bufio_read(v->bufio, hash_block, &buf); if (IS_ERR(data)) return PTR_ERR(data); aux = dm_bufio_get_aux_data(buf); if (!aux->hash_verified) { if (skip_unverified) { r = 1; goto release_ret_r; } r = verity_hash(v, verity_io_hash_req(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(memcmp(verity_io_real_digest(v, io), want_digest, v->digest_size) == 0)) aux->hash_verified = 1; else if (static_branch_unlikely(&use_tasklet_enabled) && io->in_tasklet) { /* * Error handling code (FEC included) cannot be run in a * tasklet since it may sleep, so fallback to work-queue. */ r = -EAGAIN; goto release_ret_r; } 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; } } data += offset; memcpy(want_digest, data, v->digest_size); r = 0; 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; } 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; return r; } /* * Calculates the digest for the given bio */ static int verity_for_io_block(struct dm_verity *v, struct dm_verity_io *io, struct bvec_iter *iter, struct crypto_wait *wait) { unsigned int todo = 1 << v->data_dev_block_bits; struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size); struct scatterlist sg; struct ahash_request *req = verity_io_hash_req(v, io); do { int r; unsigned int len; struct bio_vec bv = bio_iter_iovec(bio, *iter); sg_init_table(&sg, 1); len = bv.bv_len; if (likely(len >= todo)) len = todo; /* * Operating on a single page at a time looks suboptimal * until you consider the typical block size is 4,096B. * Going through this loops twice should be very rare. */ sg_set_page(&sg, bv.bv_page, len, bv.bv_offset); ahash_request_set_crypt(req, &sg, NULL, len); r = crypto_wait_req(crypto_ahash_update(req), wait); if (unlikely(r < 0)) { DMERR("%s crypto op failed: %d", __func__, r); return r; } bio_advance_iter(bio, iter, len); todo -= len; } while (todo); return 0; } /* * 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 int todo = 1 << v->data_dev_block_bits; struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size); do { int r; u8 *page; unsigned int len; struct bio_vec bv = bio_iter_iovec(bio, *iter); page = bvec_kmap_local(&bv); len = bv.bv_len; if (likely(len >= todo)) len = todo; r = process(v, io, page, len); kunmap_local(page); if (r < 0) return r; bio_advance_iter(bio, iter, len); todo -= len; } while (todo); return 0; } 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; } /* * Moves the bio iter one data block forward. */ static inline void verity_bv_skip_block(struct dm_verity *v, struct dm_verity_io *io, struct bvec_iter *iter) { struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size); bio_advance_iter(bio, iter, 1 << v->data_dev_block_bits); } /* * Verify one "dm_verity_io" structure. */ static int verity_verify_io(struct dm_verity_io *io) { bool is_zero; struct dm_verity *v = io->v; #if defined(CONFIG_DM_VERITY_FEC) struct bvec_iter start; #endif struct bvec_iter iter_copy; struct bvec_iter *iter; struct crypto_wait wait; struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size); unsigned int b; if (static_branch_unlikely(&use_tasklet_enabled) && io->in_tasklet) { /* * Copy the iterator in case we need to restart * verification in a work-queue. */ iter_copy = io->iter; iter = &iter_copy; } else iter = &io->iter; for (b = 0; b < io->n_blocks; b++) { int r; sector_t cur_block = io->block + b; struct ahash_request *req = verity_io_hash_req(v, io); if (v->validated_blocks && likely(test_bit(cur_block, v->validated_blocks))) { verity_bv_skip_block(v, io, iter); continue; } r = verity_hash_for_block(v, io, cur_block, verity_io_want_digest(v, io), &is_zero); if (unlikely(r < 0)) return r; if (is_zero) { /* * If we expect a zero block, don't validate, just * return zeros. */ r = verity_for_bv_block(v, io, iter, verity_bv_zero); if (unlikely(r < 0)) return r; continue; } r = verity_hash_init(v, req, &wait); if (unlikely(r < 0)) return r; #if defined(CONFIG_DM_VERITY_FEC) if (verity_fec_is_enabled(v)) start = *iter; #endif r = verity_for_io_block(v, io, iter, &wait); if (unlikely(r < 0)) return r; r = verity_hash_final(v, req, verity_io_real_digest(v, io), &wait); if (unlikely(r < 0)) return r; if (likely(memcmp(verity_io_real_digest(v, io), verity_io_want_digest(v, io), v->digest_size) == 0)) { if (v->validated_blocks) set_bit(cur_block, v->validated_blocks); continue; } else if (static_branch_unlikely(&use_tasklet_enabled) && io->in_tasklet) { /* * Error handling code (FEC included) cannot be run in a * tasklet since it may sleep, so fallback to work-queue. */ return -EAGAIN; #if defined(CONFIG_DM_VERITY_FEC) } else if (verity_fec_decode(v, io, DM_VERITY_BLOCK_TYPE_DATA, cur_block, NULL, &start) == 0) { continue; #endif } else { if (bio->bi_status) { /* * Error correction failed; Just return error */ return -EIO; } if (verity_handle_err(v, DM_VERITY_BLOCK_TYPE_DATA, cur_block)) return -EIO; } } return 0; } /* * Skip verity work in response to I/O error when system is shutting down. */ static inline bool verity_is_system_shutting_down(void) { return system_state == SYSTEM_HALT || system_state == SYSTEM_POWER_OFF || system_state == SYSTEM_RESTART; } /* * End one "io" structure with a given error. */ static void verity_finish_io(struct dm_verity_io *io, blk_status_t status) { struct dm_verity *v = io->v; struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size); bio->bi_end_io = io->orig_bi_end_io; bio->bi_status = status; if (!static_branch_unlikely(&use_tasklet_enabled) || !io->in_tasklet) verity_fec_finish_io(io); bio_endio(bio); } static void verity_work(struct work_struct *w) { struct dm_verity_io *io = container_of(w, struct dm_verity_io, work); io->in_tasklet = false; verity_fec_init_io(io); verity_finish_io(io, errno_to_blk_status(verity_verify_io(io))); } static void verity_tasklet(unsigned long data) { struct dm_verity_io *io = (struct dm_verity_io *)data; int err; io->in_tasklet = true; err = verity_verify_io(io); if (err == -EAGAIN) { /* fallback to retrying with work-queue */ INIT_WORK(&io->work, verity_work); queue_work(io->v->verify_wq, &io->work); return; } verity_finish_io(io, errno_to_blk_status(err)); } static void verity_end_io(struct bio *bio) { struct dm_verity_io *io = bio->bi_private; if (bio->bi_status && (!verity_fec_is_enabled(io->v) || verity_is_system_shutting_down())) { verity_finish_io(io, bio->bi_status); return; } if (static_branch_unlikely(&use_tasklet_enabled) && io->v->use_tasklet) { tasklet_init(&io->tasklet, verity_tasklet, (unsigned long)io); tasklet_schedule(&io->tasklet); } else { INIT_WORK(&io->work, verity_work); queue_work(io->v->verify_wq, &io->work); } } /* * Prefetch buffers for the specified io. * The root buffer is not prefetched, it is assumed that it will be cached * all the time. */ static void verity_prefetch_io(struct work_struct *work) { struct dm_verity_prefetch_work *pw = container_of(work, struct dm_verity_prefetch_work, work); struct dm_verity *v = pw->v; int i; for (i = v->levels - 2; i >= 0; i--) { sector_t hash_block_start; sector_t hash_block_end; verity_hash_at_level(v, pw->block, i, &hash_block_start, NULL); verity_hash_at_level(v, pw->block + pw->n_blocks - 1, i, &hash_block_end, NULL); if (!i) { unsigned int cluster = READ_ONCE(dm_verity_prefetch_cluster); cluster >>= v->data_dev_block_bits; if (unlikely(!cluster)) goto no_prefetch_cluster; if (unlikely(cluster & (cluster - 1))) cluster = 1 << __fls(cluster); hash_block_start &= ~(sector_t)(cluster - 1); hash_block_end |= cluster - 1; if (unlikely(hash_block_end >= v->hash_blocks)) hash_block_end = v->hash_blocks - 1; } no_prefetch_cluster: dm_bufio_prefetch(v->bufio, hash_block_start, hash_block_end - hash_block_start + 1); } kfree(pw); } static void verity_submit_prefetch(struct dm_verity *v, struct dm_verity_io *io) { sector_t block = io->block; unsigned int n_blocks = io->n_blocks; struct dm_verity_prefetch_work *pw; if (v->validated_blocks) { while (n_blocks && test_bit(block, v->validated_blocks)) { block++; n_blocks--; } while (n_blocks && test_bit(block + n_blocks - 1, v->validated_blocks)) n_blocks--; if (!n_blocks) return; } pw = kmalloc(sizeof(struct dm_verity_prefetch_work), GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN); if (!pw) return; INIT_WORK(&pw->work, verity_prefetch_io); pw->v = v; pw->block = block; pw->n_blocks = n_blocks; queue_work(v->verify_wq, &pw->work); } /* * Bio map function. It allocates dm_verity_io structure and bio vector and * fills them. Then it issues prefetches and the I/O. */ static int verity_map(struct dm_target *ti, struct bio *bio) { struct dm_verity *v = ti->private; struct dm_verity_io *io; bio_set_dev(bio, v->data_dev->bdev); bio->bi_iter.bi_sector = verity_map_sector(v, bio->bi_iter.bi_sector); if (((unsigned int)bio->bi_iter.bi_sector | bio_sectors(bio)) & ((1 << (v->data_dev_block_bits - SECTOR_SHIFT)) - 1)) { DMERR_LIMIT("unaligned io"); return DM_MAPIO_KILL; } if (bio_end_sector(bio) >> (v->data_dev_block_bits - SECTOR_SHIFT) > v->data_blocks) { DMERR_LIMIT("io out of range"); return DM_MAPIO_KILL; } if (bio_data_dir(bio) == WRITE) return DM_MAPIO_KILL; io = dm_per_bio_data(bio, ti->per_io_data_size); io->v = v; io->orig_bi_end_io = bio->bi_end_io; io->block = bio->bi_iter.bi_sector >> (v->data_dev_block_bits - SECTOR_SHIFT); io->n_blocks = bio->bi_iter.bi_size >> v->data_dev_block_bits; bio->bi_end_io = verity_end_io; bio->bi_private = io; io->iter = bio->bi_iter; verity_submit_prefetch(v, io); submit_bio_noacct(bio); return DM_MAPIO_SUBMITTED; } /* * Status: V (valid) or C (corruption found) */ static void verity_status(struct dm_target *ti, status_type_t type, unsigned int status_flags, char *result, unsigned int maxlen) { struct dm_verity *v = ti->private; unsigned int args = 0; unsigned int sz = 0; unsigned int x; switch (type) { case STATUSTYPE_INFO: DMEMIT("%c", v->hash_failed ? 'C' : 'V'); break; case STATUSTYPE_TABLE: DMEMIT("%u %s %s %u %u %llu %llu %s ", v->version, v->data_dev->name, v->hash_dev->name, 1 << v->data_dev_block_bits, 1 << v->hash_dev_block_bits, (unsigned long long)v->data_blocks, (unsigned long long)v->hash_start, v->alg_name ); for (x = 0; x < v->digest_size; x++) DMEMIT("%02x", v->root_digest[x]); DMEMIT(" "); if (!v->salt_size) DMEMIT("-"); else for (x = 0; x < v->salt_size; x++) DMEMIT("%02x", v->salt[x]); if (v->mode != DM_VERITY_MODE_EIO) args++; if (verity_fec_is_enabled(v)) args += DM_VERITY_OPTS_FEC; if (v->zero_digest) args++; if (v->validated_blocks) args++; if (v->use_tasklet) args++; if (v->signature_key_desc) args += DM_VERITY_ROOT_HASH_VERIFICATION_OPTS; if (!args) return; DMEMIT(" %u", args); if (v->mode != DM_VERITY_MODE_EIO) { DMEMIT(" "); switch (v->mode) { case DM_VERITY_MODE_LOGGING: DMEMIT(DM_VERITY_OPT_LOGGING); break; case DM_VERITY_MODE_RESTART: DMEMIT(DM_VERITY_OPT_RESTART); break; case DM_VERITY_MODE_PANIC: DMEMIT(DM_VERITY_OPT_PANIC); break; default: BUG(); } } if (v->zero_digest) DMEMIT(" " DM_VERITY_OPT_IGN_ZEROES); if (v->validated_blocks) DMEMIT(" " DM_VERITY_OPT_AT_MOST_ONCE); if (v->use_tasklet) DMEMIT(" " DM_VERITY_OPT_TASKLET_VERIFY); sz = verity_fec_status_table(v, sz, result, maxlen); if (v->signature_key_desc) DMEMIT(" " DM_VERITY_ROOT_HASH_VERIFICATION_OPT_SIG_KEY " %s", v->signature_key_desc); break; case STATUSTYPE_IMA: DMEMIT_TARGET_NAME_VERSION(ti->type); DMEMIT(",hash_failed=%c", v->hash_failed ? 'C' : 'V'); DMEMIT(",verity_version=%u", v->version); DMEMIT(",data_device_name=%s", v->data_dev->name); DMEMIT(",hash_device_name=%s", v->hash_dev->name); DMEMIT(",verity_algorithm=%s", v->alg_name); DMEMIT(",root_digest="); for (x = 0; x < v->digest_size; x++) DMEMIT("%02x", v->root_digest[x]); DMEMIT(",salt="); if (!v->salt_size) DMEMIT("-"); else for (x = 0; x < v->salt_size; x++) DMEMIT("%02x", v->salt[x]); DMEMIT(",ignore_zero_blocks=%c", v->zero_digest ? 'y' : 'n'); DMEMIT(",check_at_most_once=%c", v->validated_blocks ? 'y' : 'n'); if (v->signature_key_desc) DMEMIT(",root_hash_sig_key_desc=%s", v->signature_key_desc); if (v->mode != DM_VERITY_MODE_EIO) { DMEMIT(",verity_mode="); switch (v->mode) { case DM_VERITY_MODE_LOGGING: DMEMIT(DM_VERITY_OPT_LOGGING); break; case DM_VERITY_MODE_RESTART: DMEMIT(DM_VERITY_OPT_RESTART); break; case DM_VERITY_MODE_PANIC: DMEMIT(DM_VERITY_OPT_PANIC); break; default: DMEMIT("invalid"); } } DMEMIT(";"); break; } } static int verity_prepare_ioctl(struct dm_target *ti, struct block_device **bdev) { struct dm_verity *v = ti->private; *bdev = v->data_dev->bdev; if (v->data_start || ti->len != bdev_nr_sectors(v->data_dev->bdev)) return 1; return 0; } static int verity_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data) { struct dm_verity *v = ti->private; return fn(ti, v->data_dev, v->data_start, ti->len, data); } static void verity_io_hints(struct dm_target *ti, struct queue_limits *limits) { struct dm_verity *v = ti->private; if (limits->logical_block_size < 1 << v->data_dev_block_bits) limits->logical_block_size = 1 << v->data_dev_block_bits; if (limits->physical_block_size < 1 << v->data_dev_block_bits) limits->physical_block_size = 1 << v->data_dev_block_bits; blk_limits_io_min(limits, limits->logical_block_size); } static void verity_dtr(struct dm_target *ti) { struct dm_verity *v = ti->private; if (v->verify_wq) destroy_workqueue(v->verify_wq); if (v->bufio) dm_bufio_client_destroy(v->bufio); kvfree(v->validated_blocks); kfree(v->salt); kfree(v->root_digest); kfree(v->zero_digest); if (v->tfm) crypto_free_ahash(v->tfm); kfree(v->alg_name); if (v->hash_dev) dm_put_device(ti, v->hash_dev); if (v->data_dev) dm_put_device(ti, v->data_dev); verity_fec_dtr(v); kfree(v->signature_key_desc); if (v->use_tasklet) static_branch_dec(&use_tasklet_enabled); kfree(v); } static int verity_alloc_most_once(struct dm_verity *v) { struct dm_target *ti = v->ti; /* the bitset can only handle INT_MAX blocks */ if (v->data_blocks > INT_MAX) { ti->error = "device too large to use check_at_most_once"; return -E2BIG; } v->validated_blocks = kvcalloc(BITS_TO_LONGS(v->data_blocks), sizeof(unsigned long), GFP_KERNEL); if (!v->validated_blocks) { ti->error = "failed to allocate bitset for check_at_most_once"; return -ENOMEM; } return 0; } static int verity_alloc_zero_digest(struct dm_verity *v) { int r = -ENOMEM; struct ahash_request *req; u8 *zero_data; v->zero_digest = kmalloc(v->digest_size, GFP_KERNEL); if (!v->zero_digest) return r; req = kmalloc(v->ahash_reqsize, GFP_KERNEL); if (!req) 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, req, zero_data, 1 << v->data_dev_block_bits, v->zero_digest); out: kfree(req); kfree(zero_data); return r; } static inline bool verity_is_verity_mode(const char *arg_name) { return (!strcasecmp(arg_name, DM_VERITY_OPT_LOGGING) || !strcasecmp(arg_name, DM_VERITY_OPT_RESTART) || !strcasecmp(arg_name, DM_VERITY_OPT_PANIC)); } static int verity_parse_verity_mode(struct dm_verity *v, const char *arg_name) { if (v->mode) return -EINVAL; if (!strcasecmp(arg_name, DM_VERITY_OPT_LOGGING)) v->mode = DM_VERITY_MODE_LOGGING; else if (!strcasecmp(arg_name, DM_VERITY_OPT_RESTART)) v->mode = DM_VERITY_MODE_RESTART; else if (!strcasecmp(arg_name, DM_VERITY_OPT_PANIC)) v->mode = DM_VERITY_MODE_PANIC; return 0; } static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v, struct dm_verity_sig_opts *verify_args, bool only_modifier_opts) { int r = 0; unsigned int argc; struct dm_target *ti = v->ti; const char *arg_name; static const 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 (verity_is_verity_mode(arg_name)) { if (only_modifier_opts) continue; r = verity_parse_verity_mode(v, arg_name); if (r) { ti->error = "Conflicting error handling parameters"; return r; } continue; } else if (!strcasecmp(arg_name, DM_VERITY_OPT_IGN_ZEROES)) { if (only_modifier_opts) continue; r = verity_alloc_zero_digest(v); if (r) { ti->error = "Cannot allocate zero digest"; return r; } continue; } else if (!strcasecmp(arg_name, DM_VERITY_OPT_AT_MOST_ONCE)) { if (only_modifier_opts) continue; r = verity_alloc_most_once(v); if (r) return r; continue; } else if (!strcasecmp(arg_name, DM_VERITY_OPT_TASKLET_VERIFY)) { v->use_tasklet = true; static_branch_inc(&use_tasklet_enabled); continue; } else if (verity_is_fec_opt_arg(arg_name)) { if (only_modifier_opts) continue; r = verity_fec_parse_opt_args(as, v, &argc, arg_name); if (r) return r; continue; } else if (verity_verify_is_sig_opt_arg(arg_name)) { if (only_modifier_opts) continue; r = verity_verify_sig_parse_opt_args(as, v, verify_args, &argc, arg_name); if (r) return r; continue; } else if (only_modifier_opts) { /* * Ignore unrecognized opt, could easily be an extra * argument to an option whose parsing was skipped. * Normal parsing (@only_modifier_opts=false) will * properly parse all options (and their extra args). */ continue; } DMERR("Unrecognized verity feature request: %s", arg_name); ti->error = "Unrecognized verity feature request"; return -EINVAL; } while (argc && !r); return r; } /* * Target parameters: * <version> The current format is version 1. * Vsn 0 is compatible with original Chromium OS releases. * <data device> * <hash device> * <data block size> * <hash block size> * <the number of data blocks> * <hash start block> * <algorithm> * <digest> * <salt> Hex string or "-" if no salt. */ static int verity_ctr(struct dm_target *ti, unsigned int argc, char **argv) { struct dm_verity *v; struct dm_verity_sig_opts verify_args = {0}; struct dm_arg_set as; unsigned int num; unsigned long long num_ll; int r; int i; sector_t hash_position; char dummy; char *root_hash_digest_to_validate; v = kzalloc(sizeof(struct dm_verity), GFP_KERNEL); if (!v) { ti->error = "Cannot allocate verity structure"; return -ENOMEM; } 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; goto bad; } if (argc < 10) { ti->error = "Not enough arguments"; r = -EINVAL; goto bad; } /* Parse optional parameters that modify primary args */ if (argc > 10) { as.argc = argc - 10; as.argv = argv + 10; r = verity_parse_opt_args(&as, v, &verify_args, true); if (r < 0) goto bad; } if (sscanf(argv[0], "%u%c", &num, &dummy) != 1 || num > 1) { ti->error = "Invalid version"; r = -EINVAL; goto bad; } v->version = num; r = dm_get_device(ti, argv[1], FMODE_READ, &v->data_dev); if (r) { ti->error = "Data device lookup failed"; goto bad; } r = dm_get_device(ti, argv[2], FMODE_READ, &v->hash_dev); if (r) { ti->error = "Hash device lookup failed"; goto bad; } if (sscanf(argv[3], "%u%c", &num, &dummy) != 1 || !num || (num & (num - 1)) || num < bdev_logical_block_size(v->data_dev->bdev) || num > PAGE_SIZE) { ti->error = "Invalid data device block size"; r = -EINVAL; goto bad; } v->data_dev_block_bits = __ffs(num); if (sscanf(argv[4], "%u%c", &num, &dummy) != 1 || !num || (num & (num - 1)) || num < bdev_logical_block_size(v->hash_dev->bdev) || num > INT_MAX) { ti->error = "Invalid hash device block size"; r = -EINVAL; goto bad; } v->hash_dev_block_bits = __ffs(num); if (sscanf(argv[5], "%llu%c", &num_ll, &dummy) != 1 || (sector_t)(num_ll << (v->data_dev_block_bits - SECTOR_SHIFT)) >> (v->data_dev_block_bits - SECTOR_SHIFT) != num_ll) { ti->error = "Invalid data blocks"; r = -EINVAL; goto bad; } v->data_blocks = num_ll; if (ti->len > (v->data_blocks << (v->data_dev_block_bits - SECTOR_SHIFT))) { ti->error = "Data device is too small"; r = -EINVAL; goto bad; } if (sscanf(argv[6], "%llu%c", &num_ll, &dummy) != 1 || (sector_t)(num_ll << (v->hash_dev_block_bits - SECTOR_SHIFT)) >> (v->hash_dev_block_bits - SECTOR_SHIFT) != num_ll) { ti->error = "Invalid hash start"; r = -EINVAL; goto bad; } v->hash_start = num_ll; v->alg_name = kstrdup(argv[7], GFP_KERNEL); if (!v->alg_name) { ti->error = "Cannot allocate algorithm name"; r = -ENOMEM; goto bad; } v->tfm = crypto_alloc_ahash(v->alg_name, 0, v->use_tasklet ? CRYPTO_ALG_ASYNC : 0); if (IS_ERR(v->tfm)) { ti->error = "Cannot initialize hash function"; r = PTR_ERR(v->tfm); v->tfm = NULL; goto bad; } /* * dm-verity performance can vary greatly depending on which hash * algorithm implementation is used. Help people debug performance * problems by logging the ->cra_driver_name. */ DMINFO("%s using implementation \"%s\"", v->alg_name, crypto_hash_alg_common(v->tfm)->base.cra_driver_name); v->digest_size = crypto_ahash_digestsize(v->tfm); if ((1 << v->hash_dev_block_bits) < v->digest_size * 2) { ti->error = "Digest size too big"; r = -EINVAL; goto bad; } v->ahash_reqsize = sizeof(struct ahash_request) + crypto_ahash_reqsize(v->tfm); v->root_digest = kmalloc(v->digest_size, GFP_KERNEL); if (!v->root_digest) { ti->error = "Cannot allocate root digest"; r = -ENOMEM; goto bad; } if (strlen(argv[8]) != v->digest_size * 2 || hex2bin(v->root_digest, argv[8], v->digest_size)) { ti->error = "Invalid root digest"; r = -EINVAL; goto bad; } root_hash_digest_to_validate = argv[8]; if (strcmp(argv[9], "-")) { v->salt_size = strlen(argv[9]) / 2; v->salt = kmalloc(v->salt_size, GFP_KERNEL); if (!v->salt) { ti->error = "Cannot allocate salt"; r = -ENOMEM; goto bad; } if (strlen(argv[9]) != v->salt_size * 2 || hex2bin(v->salt, argv[9], v->salt_size)) { ti->error = "Invalid salt"; r = -EINVAL; goto bad; } } argv += 10; argc -= 10; /* Optional parameters */ if (argc) { as.argc = argc; as.argv = argv; r = verity_parse_opt_args(&as, v, &verify_args, false); if (r < 0) goto bad; } /* Root hash signature is a optional parameter*/ r = verity_verify_root_hash(root_hash_digest_to_validate, strlen(root_hash_digest_to_validate), verify_args.sig, verify_args.sig_size); if (r < 0) { ti->error = "Root hash verification failed"; goto bad; } v->hash_per_block_bits = __fls((1 << v->hash_dev_block_bits) / v->digest_size); v->levels = 0; if (v->data_blocks) while (v->hash_per_block_bits * v->levels < 64 && (unsigned long long)(v->data_blocks - 1) >> (v->hash_per_block_bits * v->levels)) v->levels++; if (v->levels > DM_VERITY_MAX_LEVELS) { ti->error = "Too many tree levels"; r = -E2BIG; goto bad; } hash_position = v->hash_start; for (i = v->levels - 1; i >= 0; i--) { sector_t s; v->hash_level_block[i] = hash_position; s = (v->data_blocks + ((sector_t)1 << ((i + 1) * v->hash_per_block_bits)) - 1) >> ((i + 1) * v->hash_per_block_bits); if (hash_position + s < hash_position) { ti->error = "Hash device offset overflow"; r = -E2BIG; goto bad; } hash_position += s; } v->hash_blocks = hash_position; v->bufio = dm_bufio_client_create(v->hash_dev->bdev, 1 << v->hash_dev_block_bits, 1, sizeof(struct buffer_aux), dm_bufio_alloc_callback, NULL, v->use_tasklet ? DM_BUFIO_CLIENT_NO_SLEEP : 0); if (IS_ERR(v->bufio)) { ti->error = "Cannot initialize dm-bufio"; r = PTR_ERR(v->bufio); v->bufio = NULL; goto bad; } if (dm_bufio_get_device_size(v->bufio) < v->hash_blocks) { ti->error = "Hash device is too small"; r = -E2BIG; goto bad; } /* * Using WQ_HIGHPRI improves throughput and completion latency by * reducing wait times when reading from a dm-verity device. * * Also as required for the "try_verify_in_tasklet" feature: WQ_HIGHPRI * allows verify_wq to preempt softirq since verification in tasklet * will fall-back to using it for error handling (or if the bufio cache * doesn't have required hashes). */ v->verify_wq = alloc_workqueue("kverityd", WQ_MEM_RECLAIM | WQ_HIGHPRI, 0); if (!v->verify_wq) { ti->error = "Cannot allocate workqueue"; r = -ENOMEM; goto bad; } ti->per_io_data_size = sizeof(struct dm_verity_io) + v->ahash_reqsize + v->digest_size * 2; r = verity_fec_ctr(v); if (r) goto bad; ti->per_io_data_size = roundup(ti->per_io_data_size, __alignof__(struct dm_verity_io)); verity_verify_sig_opts_cleanup(&verify_args); return 0; bad: verity_verify_sig_opts_cleanup(&verify_args); verity_dtr(ti); return r; } /* * Check whether a DM target is a verity target. */ bool dm_is_verity_target(struct dm_target *ti) { return ti->type->module == THIS_MODULE; } /* * Get the verity mode (error behavior) of a verity target. * * Returns the verity mode of the target, or -EINVAL if 'ti' is not a verity * target. */ int dm_verity_get_mode(struct dm_target *ti) { struct dm_verity *v = ti->private; if (!dm_is_verity_target(ti)) return -EINVAL; return v->mode; } /* * Get the root digest of a verity target. * * Returns a copy of the root digest, the caller is responsible for * freeing the memory of the digest. */ int dm_verity_get_root_digest(struct dm_target *ti, u8 **root_digest, unsigned int *digest_size) { struct dm_verity *v = ti->private; if (!dm_is_verity_target(ti)) return -EINVAL; *root_digest = kmemdup(v->root_digest, v->digest_size, GFP_KERNEL); if (*root_digest == NULL) return -ENOMEM; *digest_size = v->digest_size; return 0; } static struct target_type verity_target = { .name = "verity", .features = DM_TARGET_IMMUTABLE, .version = {1, 9, 0}, .module = THIS_MODULE, .ctr = 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 dm_verity_init(void) { int r; r = dm_register_target(&verity_target); if (r < 0) DMERR("register failed %d", r); return r; } static void __exit dm_verity_exit(void) { dm_unregister_target(&verity_target); } module_init(dm_verity_init); module_exit(dm_verity_exit); MODULE_AUTHOR("Mikulas Patocka <mpatocka@redhat.com>"); MODULE_AUTHOR("Mandeep Baines <msb@chromium.org>"); MODULE_AUTHOR("Will Drewry <wad@chromium.org>"); MODULE_DESCRIPTION(DM_NAME " target for transparent disk integrity checking"); MODULE_LICENSE("GPL");
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