Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2012 Red Hat, Inc. |
| 3 | * |
| 4 | * Author: Mikulas Patocka <mpatocka@redhat.com> |
| 5 | * |
| 6 | * Based on Chromium dm-verity driver (C) 2011 The Chromium OS Authors |
| 7 | * |
| 8 | * This file is released under the GPLv2. |
| 9 | * |
| 10 | * In the file "/sys/module/dm_verity/parameters/prefetch_cluster" you can set |
| 11 | * default prefetch value. Data are read in "prefetch_cluster" chunks from the |
| 12 | * hash device. Setting this greatly improves performance when data and hash |
| 13 | * are on the same disk on different partitions on devices with poor random |
| 14 | * access behavior. |
| 15 | */ |
| 16 | |
| 17 | #include "dm-bufio.h" |
| 18 | |
| 19 | #include <linux/module.h> |
| 20 | #include <linux/device-mapper.h> |
| 21 | #include <crypto/hash.h> |
| 22 | |
| 23 | #define DM_MSG_PREFIX "verity" |
| 24 | |
| 25 | #define DM_VERITY_IO_VEC_INLINE 16 |
| 26 | #define DM_VERITY_MEMPOOL_SIZE 4 |
| 27 | #define DM_VERITY_DEFAULT_PREFETCH_SIZE 262144 |
| 28 | |
| 29 | #define DM_VERITY_MAX_LEVELS 63 |
| 30 | |
| 31 | static unsigned dm_verity_prefetch_cluster = DM_VERITY_DEFAULT_PREFETCH_SIZE; |
| 32 | |
| 33 | module_param_named(prefetch_cluster, dm_verity_prefetch_cluster, uint, S_IRUGO | S_IWUSR); |
| 34 | |
| 35 | struct dm_verity { |
| 36 | struct dm_dev *data_dev; |
| 37 | struct dm_dev *hash_dev; |
| 38 | struct dm_target *ti; |
| 39 | struct dm_bufio_client *bufio; |
| 40 | char *alg_name; |
| 41 | struct crypto_shash *tfm; |
| 42 | u8 *root_digest; /* digest of the root block */ |
| 43 | u8 *salt; /* salt: its size is salt_size */ |
| 44 | unsigned salt_size; |
| 45 | sector_t data_start; /* data offset in 512-byte sectors */ |
| 46 | sector_t hash_start; /* hash start in blocks */ |
| 47 | sector_t data_blocks; /* the number of data blocks */ |
| 48 | sector_t hash_blocks; /* the number of hash blocks */ |
| 49 | unsigned char data_dev_block_bits; /* log2(data blocksize) */ |
| 50 | unsigned char hash_dev_block_bits; /* log2(hash blocksize) */ |
| 51 | unsigned char hash_per_block_bits; /* log2(hashes in hash block) */ |
| 52 | unsigned char levels; /* the number of tree levels */ |
| 53 | unsigned char version; |
| 54 | unsigned digest_size; /* digest size for the current hash algorithm */ |
| 55 | unsigned shash_descsize;/* the size of temporary space for crypto */ |
| 56 | int hash_failed; /* set to 1 if hash of any block failed */ |
| 57 | |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 58 | mempool_t *vec_mempool; /* mempool of bio vector */ |
| 59 | |
| 60 | struct workqueue_struct *verify_wq; |
| 61 | |
| 62 | /* starting blocks for each tree level. 0 is the lowest level. */ |
| 63 | sector_t hash_level_block[DM_VERITY_MAX_LEVELS]; |
| 64 | }; |
| 65 | |
| 66 | struct dm_verity_io { |
| 67 | struct dm_verity *v; |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 68 | |
| 69 | /* original values of bio->bi_end_io and bio->bi_private */ |
| 70 | bio_end_io_t *orig_bi_end_io; |
| 71 | void *orig_bi_private; |
| 72 | |
| 73 | sector_t block; |
| 74 | unsigned n_blocks; |
| 75 | |
| 76 | /* saved bio vector */ |
| 77 | struct bio_vec *io_vec; |
| 78 | unsigned io_vec_size; |
| 79 | |
| 80 | struct work_struct work; |
| 81 | |
| 82 | /* A space for short vectors; longer vectors are allocated separately. */ |
| 83 | struct bio_vec io_vec_inline[DM_VERITY_IO_VEC_INLINE]; |
| 84 | |
| 85 | /* |
| 86 | * Three variably-size fields follow this struct: |
| 87 | * |
| 88 | * u8 hash_desc[v->shash_descsize]; |
| 89 | * u8 real_digest[v->digest_size]; |
| 90 | * u8 want_digest[v->digest_size]; |
| 91 | * |
| 92 | * To access them use: io_hash_desc(), io_real_digest() and io_want_digest(). |
| 93 | */ |
| 94 | }; |
| 95 | |
Mikulas Patocka | 3b6b781 | 2013-03-20 17:21:25 +0000 | [diff] [blame] | 96 | struct dm_verity_prefetch_work { |
| 97 | struct work_struct work; |
| 98 | struct dm_verity *v; |
| 99 | sector_t block; |
| 100 | unsigned n_blocks; |
| 101 | }; |
| 102 | |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 103 | static struct shash_desc *io_hash_desc(struct dm_verity *v, struct dm_verity_io *io) |
| 104 | { |
| 105 | return (struct shash_desc *)(io + 1); |
| 106 | } |
| 107 | |
| 108 | static u8 *io_real_digest(struct dm_verity *v, struct dm_verity_io *io) |
| 109 | { |
| 110 | return (u8 *)(io + 1) + v->shash_descsize; |
| 111 | } |
| 112 | |
| 113 | static u8 *io_want_digest(struct dm_verity *v, struct dm_verity_io *io) |
| 114 | { |
| 115 | return (u8 *)(io + 1) + v->shash_descsize + v->digest_size; |
| 116 | } |
| 117 | |
| 118 | /* |
| 119 | * Auxiliary structure appended to each dm-bufio buffer. If the value |
| 120 | * hash_verified is nonzero, hash of the block has been verified. |
| 121 | * |
| 122 | * The variable hash_verified is set to 0 when allocating the buffer, then |
| 123 | * it can be changed to 1 and it is never reset to 0 again. |
| 124 | * |
| 125 | * There is no lock around this value, a race condition can at worst cause |
| 126 | * that multiple processes verify the hash of the same buffer simultaneously |
| 127 | * and write 1 to hash_verified simultaneously. |
| 128 | * This condition is harmless, so we don't need locking. |
| 129 | */ |
| 130 | struct buffer_aux { |
| 131 | int hash_verified; |
| 132 | }; |
| 133 | |
| 134 | /* |
| 135 | * Initialize struct buffer_aux for a freshly created buffer. |
| 136 | */ |
| 137 | static void dm_bufio_alloc_callback(struct dm_buffer *buf) |
| 138 | { |
| 139 | struct buffer_aux *aux = dm_bufio_get_aux_data(buf); |
| 140 | |
| 141 | aux->hash_verified = 0; |
| 142 | } |
| 143 | |
| 144 | /* |
| 145 | * Translate input sector number to the sector number on the target device. |
| 146 | */ |
| 147 | static sector_t verity_map_sector(struct dm_verity *v, sector_t bi_sector) |
| 148 | { |
| 149 | return v->data_start + dm_target_offset(v->ti, bi_sector); |
| 150 | } |
| 151 | |
| 152 | /* |
| 153 | * Return hash position of a specified block at a specified tree level |
| 154 | * (0 is the lowest level). |
| 155 | * The lowest "hash_per_block_bits"-bits of the result denote hash position |
| 156 | * inside a hash block. The remaining bits denote location of the hash block. |
| 157 | */ |
| 158 | static sector_t verity_position_at_level(struct dm_verity *v, sector_t block, |
| 159 | int level) |
| 160 | { |
| 161 | return block >> (level * v->hash_per_block_bits); |
| 162 | } |
| 163 | |
| 164 | static void verity_hash_at_level(struct dm_verity *v, sector_t block, int level, |
| 165 | sector_t *hash_block, unsigned *offset) |
| 166 | { |
| 167 | sector_t position = verity_position_at_level(v, block, level); |
| 168 | unsigned idx; |
| 169 | |
| 170 | *hash_block = v->hash_level_block[level] + (position >> v->hash_per_block_bits); |
| 171 | |
| 172 | if (!offset) |
| 173 | return; |
| 174 | |
| 175 | idx = position & ((1 << v->hash_per_block_bits) - 1); |
| 176 | if (!v->version) |
| 177 | *offset = idx * v->digest_size; |
| 178 | else |
| 179 | *offset = idx << (v->hash_dev_block_bits - v->hash_per_block_bits); |
| 180 | } |
| 181 | |
| 182 | /* |
| 183 | * Verify hash of a metadata block pertaining to the specified data block |
| 184 | * ("block" argument) at a specified level ("level" argument). |
| 185 | * |
| 186 | * On successful return, io_want_digest(v, io) contains the hash value for |
| 187 | * a lower tree level or for the data block (if we're at the lowest leve). |
| 188 | * |
| 189 | * If "skip_unverified" is true, unverified buffer is skipped and 1 is returned. |
| 190 | * If "skip_unverified" is false, unverified buffer is hashed and verified |
| 191 | * against current value of io_want_digest(v, io). |
| 192 | */ |
| 193 | static int verity_verify_level(struct dm_verity_io *io, sector_t block, |
| 194 | int level, bool skip_unverified) |
| 195 | { |
| 196 | struct dm_verity *v = io->v; |
| 197 | struct dm_buffer *buf; |
| 198 | struct buffer_aux *aux; |
| 199 | u8 *data; |
| 200 | int r; |
| 201 | sector_t hash_block; |
| 202 | unsigned offset; |
| 203 | |
| 204 | verity_hash_at_level(v, block, level, &hash_block, &offset); |
| 205 | |
| 206 | data = dm_bufio_read(v->bufio, hash_block, &buf); |
| 207 | if (unlikely(IS_ERR(data))) |
| 208 | return PTR_ERR(data); |
| 209 | |
| 210 | aux = dm_bufio_get_aux_data(buf); |
| 211 | |
| 212 | if (!aux->hash_verified) { |
| 213 | struct shash_desc *desc; |
| 214 | u8 *result; |
| 215 | |
| 216 | if (skip_unverified) { |
| 217 | r = 1; |
| 218 | goto release_ret_r; |
| 219 | } |
| 220 | |
| 221 | desc = io_hash_desc(v, io); |
| 222 | desc->tfm = v->tfm; |
| 223 | desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; |
| 224 | r = crypto_shash_init(desc); |
| 225 | if (r < 0) { |
| 226 | DMERR("crypto_shash_init failed: %d", r); |
| 227 | goto release_ret_r; |
| 228 | } |
| 229 | |
| 230 | if (likely(v->version >= 1)) { |
| 231 | r = crypto_shash_update(desc, v->salt, v->salt_size); |
| 232 | if (r < 0) { |
| 233 | DMERR("crypto_shash_update failed: %d", r); |
| 234 | goto release_ret_r; |
| 235 | } |
| 236 | } |
| 237 | |
| 238 | r = crypto_shash_update(desc, data, 1 << v->hash_dev_block_bits); |
| 239 | if (r < 0) { |
| 240 | DMERR("crypto_shash_update failed: %d", r); |
| 241 | goto release_ret_r; |
| 242 | } |
| 243 | |
| 244 | if (!v->version) { |
| 245 | r = crypto_shash_update(desc, v->salt, v->salt_size); |
| 246 | if (r < 0) { |
| 247 | DMERR("crypto_shash_update failed: %d", r); |
| 248 | goto release_ret_r; |
| 249 | } |
| 250 | } |
| 251 | |
| 252 | result = io_real_digest(v, io); |
| 253 | r = crypto_shash_final(desc, result); |
| 254 | if (r < 0) { |
| 255 | DMERR("crypto_shash_final failed: %d", r); |
| 256 | goto release_ret_r; |
| 257 | } |
| 258 | if (unlikely(memcmp(result, io_want_digest(v, io), v->digest_size))) { |
| 259 | DMERR_LIMIT("metadata block %llu is corrupted", |
| 260 | (unsigned long long)hash_block); |
| 261 | v->hash_failed = 1; |
| 262 | r = -EIO; |
| 263 | goto release_ret_r; |
| 264 | } else |
| 265 | aux->hash_verified = 1; |
| 266 | } |
| 267 | |
| 268 | data += offset; |
| 269 | |
| 270 | memcpy(io_want_digest(v, io), data, v->digest_size); |
| 271 | |
| 272 | dm_bufio_release(buf); |
| 273 | return 0; |
| 274 | |
| 275 | release_ret_r: |
| 276 | dm_bufio_release(buf); |
| 277 | |
| 278 | return r; |
| 279 | } |
| 280 | |
| 281 | /* |
| 282 | * Verify one "dm_verity_io" structure. |
| 283 | */ |
| 284 | static int verity_verify_io(struct dm_verity_io *io) |
| 285 | { |
| 286 | struct dm_verity *v = io->v; |
| 287 | unsigned b; |
| 288 | int i; |
| 289 | unsigned vector = 0, offset = 0; |
| 290 | |
| 291 | for (b = 0; b < io->n_blocks; b++) { |
| 292 | struct shash_desc *desc; |
| 293 | u8 *result; |
| 294 | int r; |
| 295 | unsigned todo; |
| 296 | |
| 297 | if (likely(v->levels)) { |
| 298 | /* |
| 299 | * First, we try to get the requested hash for |
| 300 | * the current block. If the hash block itself is |
| 301 | * verified, zero is returned. If it isn't, this |
| 302 | * function returns 0 and we fall back to whole |
| 303 | * chain verification. |
| 304 | */ |
| 305 | int r = verity_verify_level(io, io->block + b, 0, true); |
| 306 | if (likely(!r)) |
| 307 | goto test_block_hash; |
| 308 | if (r < 0) |
| 309 | return r; |
| 310 | } |
| 311 | |
| 312 | memcpy(io_want_digest(v, io), v->root_digest, v->digest_size); |
| 313 | |
| 314 | for (i = v->levels - 1; i >= 0; i--) { |
| 315 | int r = verity_verify_level(io, io->block + b, i, false); |
| 316 | if (unlikely(r)) |
| 317 | return r; |
| 318 | } |
| 319 | |
| 320 | test_block_hash: |
| 321 | desc = io_hash_desc(v, io); |
| 322 | desc->tfm = v->tfm; |
| 323 | desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; |
| 324 | r = crypto_shash_init(desc); |
| 325 | if (r < 0) { |
| 326 | DMERR("crypto_shash_init failed: %d", r); |
| 327 | return r; |
| 328 | } |
| 329 | |
| 330 | if (likely(v->version >= 1)) { |
| 331 | r = crypto_shash_update(desc, v->salt, v->salt_size); |
| 332 | if (r < 0) { |
| 333 | DMERR("crypto_shash_update failed: %d", r); |
| 334 | return r; |
| 335 | } |
| 336 | } |
| 337 | |
| 338 | todo = 1 << v->data_dev_block_bits; |
| 339 | do { |
| 340 | struct bio_vec *bv; |
| 341 | u8 *page; |
| 342 | unsigned len; |
| 343 | |
| 344 | BUG_ON(vector >= io->io_vec_size); |
| 345 | bv = &io->io_vec[vector]; |
| 346 | page = kmap_atomic(bv->bv_page); |
| 347 | len = bv->bv_len - offset; |
| 348 | if (likely(len >= todo)) |
| 349 | len = todo; |
| 350 | r = crypto_shash_update(desc, |
| 351 | page + bv->bv_offset + offset, len); |
| 352 | kunmap_atomic(page); |
| 353 | if (r < 0) { |
| 354 | DMERR("crypto_shash_update failed: %d", r); |
| 355 | return r; |
| 356 | } |
| 357 | offset += len; |
| 358 | if (likely(offset == bv->bv_len)) { |
| 359 | offset = 0; |
| 360 | vector++; |
| 361 | } |
| 362 | todo -= len; |
| 363 | } while (todo); |
| 364 | |
| 365 | if (!v->version) { |
| 366 | r = crypto_shash_update(desc, v->salt, v->salt_size); |
| 367 | if (r < 0) { |
| 368 | DMERR("crypto_shash_update failed: %d", r); |
| 369 | return r; |
| 370 | } |
| 371 | } |
| 372 | |
| 373 | result = io_real_digest(v, io); |
| 374 | r = crypto_shash_final(desc, result); |
| 375 | if (r < 0) { |
| 376 | DMERR("crypto_shash_final failed: %d", r); |
| 377 | return r; |
| 378 | } |
| 379 | if (unlikely(memcmp(result, io_want_digest(v, io), v->digest_size))) { |
| 380 | DMERR_LIMIT("data block %llu is corrupted", |
| 381 | (unsigned long long)(io->block + b)); |
| 382 | v->hash_failed = 1; |
| 383 | return -EIO; |
| 384 | } |
| 385 | } |
| 386 | BUG_ON(vector != io->io_vec_size); |
| 387 | BUG_ON(offset); |
| 388 | |
| 389 | return 0; |
| 390 | } |
| 391 | |
| 392 | /* |
| 393 | * End one "io" structure with a given error. |
| 394 | */ |
| 395 | static void verity_finish_io(struct dm_verity_io *io, int error) |
| 396 | { |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 397 | struct dm_verity *v = io->v; |
Mikulas Patocka | e42c3f9 | 2012-12-21 20:23:38 +0000 | [diff] [blame] | 398 | struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_bio_data_size); |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 399 | |
| 400 | bio->bi_end_io = io->orig_bi_end_io; |
| 401 | bio->bi_private = io->orig_bi_private; |
| 402 | |
| 403 | if (io->io_vec != io->io_vec_inline) |
| 404 | mempool_free(io->io_vec, v->vec_mempool); |
| 405 | |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 406 | bio_endio(bio, error); |
| 407 | } |
| 408 | |
| 409 | static void verity_work(struct work_struct *w) |
| 410 | { |
| 411 | struct dm_verity_io *io = container_of(w, struct dm_verity_io, work); |
| 412 | |
| 413 | verity_finish_io(io, verity_verify_io(io)); |
| 414 | } |
| 415 | |
| 416 | static void verity_end_io(struct bio *bio, int error) |
| 417 | { |
| 418 | struct dm_verity_io *io = bio->bi_private; |
| 419 | |
| 420 | if (error) { |
| 421 | verity_finish_io(io, error); |
| 422 | return; |
| 423 | } |
| 424 | |
| 425 | INIT_WORK(&io->work, verity_work); |
| 426 | queue_work(io->v->verify_wq, &io->work); |
| 427 | } |
| 428 | |
| 429 | /* |
| 430 | * Prefetch buffers for the specified io. |
| 431 | * The root buffer is not prefetched, it is assumed that it will be cached |
| 432 | * all the time. |
| 433 | */ |
Mikulas Patocka | 3b6b781 | 2013-03-20 17:21:25 +0000 | [diff] [blame] | 434 | static void verity_prefetch_io(struct work_struct *work) |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 435 | { |
Mikulas Patocka | 3b6b781 | 2013-03-20 17:21:25 +0000 | [diff] [blame] | 436 | struct dm_verity_prefetch_work *pw = |
| 437 | container_of(work, struct dm_verity_prefetch_work, work); |
| 438 | struct dm_verity *v = pw->v; |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 439 | int i; |
| 440 | |
| 441 | for (i = v->levels - 2; i >= 0; i--) { |
| 442 | sector_t hash_block_start; |
| 443 | sector_t hash_block_end; |
Mikulas Patocka | 3b6b781 | 2013-03-20 17:21:25 +0000 | [diff] [blame] | 444 | verity_hash_at_level(v, pw->block, i, &hash_block_start, NULL); |
| 445 | verity_hash_at_level(v, pw->block + pw->n_blocks - 1, i, &hash_block_end, NULL); |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 446 | if (!i) { |
Mikulas Patocka | fe5fe90 | 2012-10-12 16:59:46 +0100 | [diff] [blame] | 447 | unsigned cluster = ACCESS_ONCE(dm_verity_prefetch_cluster); |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 448 | |
| 449 | cluster >>= v->data_dev_block_bits; |
| 450 | if (unlikely(!cluster)) |
| 451 | goto no_prefetch_cluster; |
| 452 | |
| 453 | if (unlikely(cluster & (cluster - 1))) |
Mikulas Patocka | 553d8fe | 2013-07-10 23:41:17 +0100 | [diff] [blame] | 454 | cluster = 1 << __fls(cluster); |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 455 | |
| 456 | hash_block_start &= ~(sector_t)(cluster - 1); |
| 457 | hash_block_end |= cluster - 1; |
| 458 | if (unlikely(hash_block_end >= v->hash_blocks)) |
| 459 | hash_block_end = v->hash_blocks - 1; |
| 460 | } |
| 461 | no_prefetch_cluster: |
| 462 | dm_bufio_prefetch(v->bufio, hash_block_start, |
| 463 | hash_block_end - hash_block_start + 1); |
| 464 | } |
Mikulas Patocka | 3b6b781 | 2013-03-20 17:21:25 +0000 | [diff] [blame] | 465 | |
| 466 | kfree(pw); |
| 467 | } |
| 468 | |
| 469 | static void verity_submit_prefetch(struct dm_verity *v, struct dm_verity_io *io) |
| 470 | { |
| 471 | struct dm_verity_prefetch_work *pw; |
| 472 | |
| 473 | pw = kmalloc(sizeof(struct dm_verity_prefetch_work), |
| 474 | GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN); |
| 475 | |
| 476 | if (!pw) |
| 477 | return; |
| 478 | |
| 479 | INIT_WORK(&pw->work, verity_prefetch_io); |
| 480 | pw->v = v; |
| 481 | pw->block = io->block; |
| 482 | pw->n_blocks = io->n_blocks; |
| 483 | queue_work(v->verify_wq, &pw->work); |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 484 | } |
| 485 | |
| 486 | /* |
| 487 | * Bio map function. It allocates dm_verity_io structure and bio vector and |
| 488 | * fills them. Then it issues prefetches and the I/O. |
| 489 | */ |
Mikulas Patocka | 7de3ee5 | 2012-12-21 20:23:41 +0000 | [diff] [blame] | 490 | static int verity_map(struct dm_target *ti, struct bio *bio) |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 491 | { |
| 492 | struct dm_verity *v = ti->private; |
| 493 | struct dm_verity_io *io; |
| 494 | |
| 495 | bio->bi_bdev = v->data_dev->bdev; |
| 496 | bio->bi_sector = verity_map_sector(v, bio->bi_sector); |
| 497 | |
| 498 | if (((unsigned)bio->bi_sector | bio_sectors(bio)) & |
| 499 | ((1 << (v->data_dev_block_bits - SECTOR_SHIFT)) - 1)) { |
| 500 | DMERR_LIMIT("unaligned io"); |
| 501 | return -EIO; |
| 502 | } |
| 503 | |
Kent Overstreet | f73a1c7 | 2012-09-25 15:05:12 -0700 | [diff] [blame] | 504 | if (bio_end_sector(bio) >> |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 505 | (v->data_dev_block_bits - SECTOR_SHIFT) > v->data_blocks) { |
| 506 | DMERR_LIMIT("io out of range"); |
| 507 | return -EIO; |
| 508 | } |
| 509 | |
| 510 | if (bio_data_dir(bio) == WRITE) |
| 511 | return -EIO; |
| 512 | |
Mikulas Patocka | e42c3f9 | 2012-12-21 20:23:38 +0000 | [diff] [blame] | 513 | io = dm_per_bio_data(bio, ti->per_bio_data_size); |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 514 | io->v = v; |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 515 | io->orig_bi_end_io = bio->bi_end_io; |
| 516 | io->orig_bi_private = bio->bi_private; |
| 517 | io->block = bio->bi_sector >> (v->data_dev_block_bits - SECTOR_SHIFT); |
| 518 | io->n_blocks = bio->bi_size >> v->data_dev_block_bits; |
| 519 | |
| 520 | bio->bi_end_io = verity_end_io; |
| 521 | bio->bi_private = io; |
Kent Overstreet | 4f2ac93 | 2012-09-04 15:23:14 -0700 | [diff] [blame] | 522 | io->io_vec_size = bio_segments(bio); |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 523 | if (io->io_vec_size < DM_VERITY_IO_VEC_INLINE) |
| 524 | io->io_vec = io->io_vec_inline; |
| 525 | else |
| 526 | io->io_vec = mempool_alloc(v->vec_mempool, GFP_NOIO); |
| 527 | memcpy(io->io_vec, bio_iovec(bio), |
| 528 | io->io_vec_size * sizeof(struct bio_vec)); |
| 529 | |
Mikulas Patocka | 3b6b781 | 2013-03-20 17:21:25 +0000 | [diff] [blame] | 530 | verity_submit_prefetch(v, io); |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 531 | |
| 532 | generic_make_request(bio); |
| 533 | |
| 534 | return DM_MAPIO_SUBMITTED; |
| 535 | } |
| 536 | |
| 537 | /* |
| 538 | * Status: V (valid) or C (corruption found) |
| 539 | */ |
Mikulas Patocka | fd7c092e | 2013-03-01 22:45:44 +0000 | [diff] [blame] | 540 | static void verity_status(struct dm_target *ti, status_type_t type, |
| 541 | unsigned status_flags, char *result, unsigned maxlen) |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 542 | { |
| 543 | struct dm_verity *v = ti->private; |
| 544 | unsigned sz = 0; |
| 545 | unsigned x; |
| 546 | |
| 547 | switch (type) { |
| 548 | case STATUSTYPE_INFO: |
| 549 | DMEMIT("%c", v->hash_failed ? 'C' : 'V'); |
| 550 | break; |
| 551 | case STATUSTYPE_TABLE: |
| 552 | DMEMIT("%u %s %s %u %u %llu %llu %s ", |
| 553 | v->version, |
| 554 | v->data_dev->name, |
| 555 | v->hash_dev->name, |
| 556 | 1 << v->data_dev_block_bits, |
| 557 | 1 << v->hash_dev_block_bits, |
| 558 | (unsigned long long)v->data_blocks, |
| 559 | (unsigned long long)v->hash_start, |
| 560 | v->alg_name |
| 561 | ); |
| 562 | for (x = 0; x < v->digest_size; x++) |
| 563 | DMEMIT("%02x", v->root_digest[x]); |
| 564 | DMEMIT(" "); |
| 565 | if (!v->salt_size) |
| 566 | DMEMIT("-"); |
| 567 | else |
| 568 | for (x = 0; x < v->salt_size; x++) |
| 569 | DMEMIT("%02x", v->salt[x]); |
| 570 | break; |
| 571 | } |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 572 | } |
| 573 | |
| 574 | static int verity_ioctl(struct dm_target *ti, unsigned cmd, |
| 575 | unsigned long arg) |
| 576 | { |
| 577 | struct dm_verity *v = ti->private; |
| 578 | int r = 0; |
| 579 | |
| 580 | if (v->data_start || |
| 581 | ti->len != i_size_read(v->data_dev->bdev->bd_inode) >> SECTOR_SHIFT) |
| 582 | r = scsi_verify_blk_ioctl(NULL, cmd); |
| 583 | |
| 584 | return r ? : __blkdev_driver_ioctl(v->data_dev->bdev, v->data_dev->mode, |
| 585 | cmd, arg); |
| 586 | } |
| 587 | |
| 588 | static int verity_merge(struct dm_target *ti, struct bvec_merge_data *bvm, |
| 589 | struct bio_vec *biovec, int max_size) |
| 590 | { |
| 591 | struct dm_verity *v = ti->private; |
| 592 | struct request_queue *q = bdev_get_queue(v->data_dev->bdev); |
| 593 | |
| 594 | if (!q->merge_bvec_fn) |
| 595 | return max_size; |
| 596 | |
| 597 | bvm->bi_bdev = v->data_dev->bdev; |
| 598 | bvm->bi_sector = verity_map_sector(v, bvm->bi_sector); |
| 599 | |
| 600 | return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); |
| 601 | } |
| 602 | |
| 603 | static int verity_iterate_devices(struct dm_target *ti, |
| 604 | iterate_devices_callout_fn fn, void *data) |
| 605 | { |
| 606 | struct dm_verity *v = ti->private; |
| 607 | |
| 608 | return fn(ti, v->data_dev, v->data_start, ti->len, data); |
| 609 | } |
| 610 | |
| 611 | static void verity_io_hints(struct dm_target *ti, struct queue_limits *limits) |
| 612 | { |
| 613 | struct dm_verity *v = ti->private; |
| 614 | |
| 615 | if (limits->logical_block_size < 1 << v->data_dev_block_bits) |
| 616 | limits->logical_block_size = 1 << v->data_dev_block_bits; |
| 617 | |
| 618 | if (limits->physical_block_size < 1 << v->data_dev_block_bits) |
| 619 | limits->physical_block_size = 1 << v->data_dev_block_bits; |
| 620 | |
| 621 | blk_limits_io_min(limits, limits->logical_block_size); |
| 622 | } |
| 623 | |
| 624 | static void verity_dtr(struct dm_target *ti) |
| 625 | { |
| 626 | struct dm_verity *v = ti->private; |
| 627 | |
| 628 | if (v->verify_wq) |
| 629 | destroy_workqueue(v->verify_wq); |
| 630 | |
| 631 | if (v->vec_mempool) |
| 632 | mempool_destroy(v->vec_mempool); |
| 633 | |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 634 | if (v->bufio) |
| 635 | dm_bufio_client_destroy(v->bufio); |
| 636 | |
| 637 | kfree(v->salt); |
| 638 | kfree(v->root_digest); |
| 639 | |
| 640 | if (v->tfm) |
| 641 | crypto_free_shash(v->tfm); |
| 642 | |
| 643 | kfree(v->alg_name); |
| 644 | |
| 645 | if (v->hash_dev) |
| 646 | dm_put_device(ti, v->hash_dev); |
| 647 | |
| 648 | if (v->data_dev) |
| 649 | dm_put_device(ti, v->data_dev); |
| 650 | |
| 651 | kfree(v); |
| 652 | } |
| 653 | |
| 654 | /* |
| 655 | * Target parameters: |
| 656 | * <version> The current format is version 1. |
| 657 | * Vsn 0 is compatible with original Chromium OS releases. |
| 658 | * <data device> |
| 659 | * <hash device> |
| 660 | * <data block size> |
| 661 | * <hash block size> |
| 662 | * <the number of data blocks> |
| 663 | * <hash start block> |
| 664 | * <algorithm> |
| 665 | * <digest> |
| 666 | * <salt> Hex string or "-" if no salt. |
| 667 | */ |
| 668 | static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv) |
| 669 | { |
| 670 | struct dm_verity *v; |
| 671 | unsigned num; |
| 672 | unsigned long long num_ll; |
| 673 | int r; |
| 674 | int i; |
| 675 | sector_t hash_position; |
| 676 | char dummy; |
| 677 | |
| 678 | v = kzalloc(sizeof(struct dm_verity), GFP_KERNEL); |
| 679 | if (!v) { |
| 680 | ti->error = "Cannot allocate verity structure"; |
| 681 | return -ENOMEM; |
| 682 | } |
| 683 | ti->private = v; |
| 684 | v->ti = ti; |
| 685 | |
| 686 | if ((dm_table_get_mode(ti->table) & ~FMODE_READ)) { |
| 687 | ti->error = "Device must be readonly"; |
| 688 | r = -EINVAL; |
| 689 | goto bad; |
| 690 | } |
| 691 | |
| 692 | if (argc != 10) { |
| 693 | ti->error = "Invalid argument count: exactly 10 arguments required"; |
| 694 | r = -EINVAL; |
| 695 | goto bad; |
| 696 | } |
| 697 | |
Mikulas Patocka | 5d8be84 | 2013-07-10 23:41:17 +0100 | [diff] [blame] | 698 | if (sscanf(argv[0], "%u%c", &num, &dummy) != 1 || |
| 699 | num > 1) { |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 700 | ti->error = "Invalid version"; |
| 701 | r = -EINVAL; |
| 702 | goto bad; |
| 703 | } |
| 704 | v->version = num; |
| 705 | |
| 706 | r = dm_get_device(ti, argv[1], FMODE_READ, &v->data_dev); |
| 707 | if (r) { |
| 708 | ti->error = "Data device lookup failed"; |
| 709 | goto bad; |
| 710 | } |
| 711 | |
| 712 | r = dm_get_device(ti, argv[2], FMODE_READ, &v->hash_dev); |
| 713 | if (r) { |
| 714 | ti->error = "Data device lookup failed"; |
| 715 | goto bad; |
| 716 | } |
| 717 | |
| 718 | if (sscanf(argv[3], "%u%c", &num, &dummy) != 1 || |
| 719 | !num || (num & (num - 1)) || |
| 720 | num < bdev_logical_block_size(v->data_dev->bdev) || |
| 721 | num > PAGE_SIZE) { |
| 722 | ti->error = "Invalid data device block size"; |
| 723 | r = -EINVAL; |
| 724 | goto bad; |
| 725 | } |
Mikulas Patocka | 553d8fe | 2013-07-10 23:41:17 +0100 | [diff] [blame] | 726 | v->data_dev_block_bits = __ffs(num); |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 727 | |
| 728 | if (sscanf(argv[4], "%u%c", &num, &dummy) != 1 || |
| 729 | !num || (num & (num - 1)) || |
| 730 | num < bdev_logical_block_size(v->hash_dev->bdev) || |
| 731 | num > INT_MAX) { |
| 732 | ti->error = "Invalid hash device block size"; |
| 733 | r = -EINVAL; |
| 734 | goto bad; |
| 735 | } |
Mikulas Patocka | 553d8fe | 2013-07-10 23:41:17 +0100 | [diff] [blame] | 736 | v->hash_dev_block_bits = __ffs(num); |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 737 | |
| 738 | if (sscanf(argv[5], "%llu%c", &num_ll, &dummy) != 1 || |
Mikulas Patocka | 1d55f6b | 2012-09-26 23:45:48 +0100 | [diff] [blame] | 739 | (sector_t)(num_ll << (v->data_dev_block_bits - SECTOR_SHIFT)) |
| 740 | >> (v->data_dev_block_bits - SECTOR_SHIFT) != num_ll) { |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 741 | ti->error = "Invalid data blocks"; |
| 742 | r = -EINVAL; |
| 743 | goto bad; |
| 744 | } |
| 745 | v->data_blocks = num_ll; |
| 746 | |
| 747 | if (ti->len > (v->data_blocks << (v->data_dev_block_bits - SECTOR_SHIFT))) { |
| 748 | ti->error = "Data device is too small"; |
| 749 | r = -EINVAL; |
| 750 | goto bad; |
| 751 | } |
| 752 | |
| 753 | if (sscanf(argv[6], "%llu%c", &num_ll, &dummy) != 1 || |
Mikulas Patocka | 1d55f6b | 2012-09-26 23:45:48 +0100 | [diff] [blame] | 754 | (sector_t)(num_ll << (v->hash_dev_block_bits - SECTOR_SHIFT)) |
| 755 | >> (v->hash_dev_block_bits - SECTOR_SHIFT) != num_ll) { |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 756 | ti->error = "Invalid hash start"; |
| 757 | r = -EINVAL; |
| 758 | goto bad; |
| 759 | } |
| 760 | v->hash_start = num_ll; |
| 761 | |
| 762 | v->alg_name = kstrdup(argv[7], GFP_KERNEL); |
| 763 | if (!v->alg_name) { |
| 764 | ti->error = "Cannot allocate algorithm name"; |
| 765 | r = -ENOMEM; |
| 766 | goto bad; |
| 767 | } |
| 768 | |
| 769 | v->tfm = crypto_alloc_shash(v->alg_name, 0, 0); |
| 770 | if (IS_ERR(v->tfm)) { |
| 771 | ti->error = "Cannot initialize hash function"; |
| 772 | r = PTR_ERR(v->tfm); |
| 773 | v->tfm = NULL; |
| 774 | goto bad; |
| 775 | } |
| 776 | v->digest_size = crypto_shash_digestsize(v->tfm); |
| 777 | if ((1 << v->hash_dev_block_bits) < v->digest_size * 2) { |
| 778 | ti->error = "Digest size too big"; |
| 779 | r = -EINVAL; |
| 780 | goto bad; |
| 781 | } |
| 782 | v->shash_descsize = |
| 783 | sizeof(struct shash_desc) + crypto_shash_descsize(v->tfm); |
| 784 | |
| 785 | v->root_digest = kmalloc(v->digest_size, GFP_KERNEL); |
| 786 | if (!v->root_digest) { |
| 787 | ti->error = "Cannot allocate root digest"; |
| 788 | r = -ENOMEM; |
| 789 | goto bad; |
| 790 | } |
| 791 | if (strlen(argv[8]) != v->digest_size * 2 || |
| 792 | hex2bin(v->root_digest, argv[8], v->digest_size)) { |
| 793 | ti->error = "Invalid root digest"; |
| 794 | r = -EINVAL; |
| 795 | goto bad; |
| 796 | } |
| 797 | |
| 798 | if (strcmp(argv[9], "-")) { |
| 799 | v->salt_size = strlen(argv[9]) / 2; |
| 800 | v->salt = kmalloc(v->salt_size, GFP_KERNEL); |
| 801 | if (!v->salt) { |
| 802 | ti->error = "Cannot allocate salt"; |
| 803 | r = -ENOMEM; |
| 804 | goto bad; |
| 805 | } |
| 806 | if (strlen(argv[9]) != v->salt_size * 2 || |
| 807 | hex2bin(v->salt, argv[9], v->salt_size)) { |
| 808 | ti->error = "Invalid salt"; |
| 809 | r = -EINVAL; |
| 810 | goto bad; |
| 811 | } |
| 812 | } |
| 813 | |
| 814 | v->hash_per_block_bits = |
Mikulas Patocka | 553d8fe | 2013-07-10 23:41:17 +0100 | [diff] [blame] | 815 | __fls((1 << v->hash_dev_block_bits) / v->digest_size); |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 816 | |
| 817 | v->levels = 0; |
| 818 | if (v->data_blocks) |
| 819 | while (v->hash_per_block_bits * v->levels < 64 && |
| 820 | (unsigned long long)(v->data_blocks - 1) >> |
| 821 | (v->hash_per_block_bits * v->levels)) |
| 822 | v->levels++; |
| 823 | |
| 824 | if (v->levels > DM_VERITY_MAX_LEVELS) { |
| 825 | ti->error = "Too many tree levels"; |
| 826 | r = -E2BIG; |
| 827 | goto bad; |
| 828 | } |
| 829 | |
| 830 | hash_position = v->hash_start; |
| 831 | for (i = v->levels - 1; i >= 0; i--) { |
| 832 | sector_t s; |
| 833 | v->hash_level_block[i] = hash_position; |
Mikulas Patocka | b1bf2de | 2013-07-10 23:41:16 +0100 | [diff] [blame] | 834 | s = (v->data_blocks + ((sector_t)1 << ((i + 1) * v->hash_per_block_bits)) - 1) |
| 835 | >> ((i + 1) * v->hash_per_block_bits); |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 836 | if (hash_position + s < hash_position) { |
| 837 | ti->error = "Hash device offset overflow"; |
| 838 | r = -E2BIG; |
| 839 | goto bad; |
| 840 | } |
| 841 | hash_position += s; |
| 842 | } |
| 843 | v->hash_blocks = hash_position; |
| 844 | |
| 845 | v->bufio = dm_bufio_client_create(v->hash_dev->bdev, |
| 846 | 1 << v->hash_dev_block_bits, 1, sizeof(struct buffer_aux), |
| 847 | dm_bufio_alloc_callback, NULL); |
| 848 | if (IS_ERR(v->bufio)) { |
| 849 | ti->error = "Cannot initialize dm-bufio"; |
| 850 | r = PTR_ERR(v->bufio); |
| 851 | v->bufio = NULL; |
| 852 | goto bad; |
| 853 | } |
| 854 | |
| 855 | if (dm_bufio_get_device_size(v->bufio) < v->hash_blocks) { |
| 856 | ti->error = "Hash device is too small"; |
| 857 | r = -E2BIG; |
| 858 | goto bad; |
| 859 | } |
| 860 | |
Mikulas Patocka | e42c3f9 | 2012-12-21 20:23:38 +0000 | [diff] [blame] | 861 | ti->per_bio_data_size = roundup(sizeof(struct dm_verity_io) + v->shash_descsize + v->digest_size * 2, __alignof__(struct dm_verity_io)); |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 862 | |
| 863 | v->vec_mempool = mempool_create_kmalloc_pool(DM_VERITY_MEMPOOL_SIZE, |
| 864 | BIO_MAX_PAGES * sizeof(struct bio_vec)); |
| 865 | if (!v->vec_mempool) { |
| 866 | ti->error = "Cannot allocate vector mempool"; |
| 867 | r = -ENOMEM; |
| 868 | goto bad; |
| 869 | } |
| 870 | |
| 871 | /* WQ_UNBOUND greatly improves performance when running on ramdisk */ |
| 872 | v->verify_wq = alloc_workqueue("kverityd", WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM | WQ_UNBOUND, num_online_cpus()); |
| 873 | if (!v->verify_wq) { |
| 874 | ti->error = "Cannot allocate workqueue"; |
| 875 | r = -ENOMEM; |
| 876 | goto bad; |
| 877 | } |
| 878 | |
| 879 | return 0; |
| 880 | |
| 881 | bad: |
| 882 | verity_dtr(ti); |
| 883 | |
| 884 | return r; |
| 885 | } |
| 886 | |
| 887 | static struct target_type verity_target = { |
| 888 | .name = "verity", |
Mikulas Patocka | 3b6b781 | 2013-03-20 17:21:25 +0000 | [diff] [blame] | 889 | .version = {1, 2, 0}, |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 890 | .module = THIS_MODULE, |
| 891 | .ctr = verity_ctr, |
| 892 | .dtr = verity_dtr, |
| 893 | .map = verity_map, |
| 894 | .status = verity_status, |
| 895 | .ioctl = verity_ioctl, |
| 896 | .merge = verity_merge, |
| 897 | .iterate_devices = verity_iterate_devices, |
| 898 | .io_hints = verity_io_hints, |
| 899 | }; |
| 900 | |
| 901 | static int __init dm_verity_init(void) |
| 902 | { |
| 903 | int r; |
| 904 | |
| 905 | r = dm_register_target(&verity_target); |
| 906 | if (r < 0) |
| 907 | DMERR("register failed %d", r); |
| 908 | |
| 909 | return r; |
| 910 | } |
| 911 | |
| 912 | static void __exit dm_verity_exit(void) |
| 913 | { |
| 914 | dm_unregister_target(&verity_target); |
| 915 | } |
| 916 | |
| 917 | module_init(dm_verity_init); |
| 918 | module_exit(dm_verity_exit); |
| 919 | |
| 920 | MODULE_AUTHOR("Mikulas Patocka <mpatocka@redhat.com>"); |
| 921 | MODULE_AUTHOR("Mandeep Baines <msb@chromium.org>"); |
| 922 | MODULE_AUTHOR("Will Drewry <wad@chromium.org>"); |
| 923 | MODULE_DESCRIPTION(DM_NAME " target for transparent disk integrity checking"); |
| 924 | MODULE_LICENSE("GPL"); |