1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * This file is part of UBIFS. 4 * 5 * Copyright (C) 2006-2008 Nokia Corporation. 6 * 7 * Authors: Artem Bityutskiy (Битюцкий Артём) 8 * Adrian Hunter 9 */ 10 11 /* 12 * This file implements UBIFS superblock. The superblock is stored at the first 13 * LEB of the volume and is never changed by UBIFS. Only user-space tools may 14 * change it. The superblock node mostly contains geometry information. 15 */ 16 17 #include "ubifs.h" 18 #include <linux/slab.h> 19 #include <linux/math64.h> 20 #include <linux/uuid.h> 21 22 /* 23 * Default journal size in logical eraseblocks as a percent of total 24 * flash size. 25 */ 26 #define DEFAULT_JNL_PERCENT 5 27 28 /* Default maximum journal size in bytes */ 29 #define DEFAULT_MAX_JNL (32*1024*1024) 30 31 /* Default indexing tree fanout */ 32 #define DEFAULT_FANOUT 8 33 34 /* Default number of data journal heads */ 35 #define DEFAULT_JHEADS_CNT 1 36 37 /* Default positions of different LEBs in the main area */ 38 #define DEFAULT_IDX_LEB 0 39 #define DEFAULT_DATA_LEB 1 40 #define DEFAULT_GC_LEB 2 41 42 /* Default number of LEB numbers in LPT's save table */ 43 #define DEFAULT_LSAVE_CNT 256 44 45 /* Default reserved pool size as a percent of maximum free space */ 46 #define DEFAULT_RP_PERCENT 5 47 48 /* The default maximum size of reserved pool in bytes */ 49 #define DEFAULT_MAX_RP_SIZE (5*1024*1024) 50 51 /* Default time granularity in nanoseconds */ 52 #define DEFAULT_TIME_GRAN 1000000000 53 54 static int get_default_compressor(struct ubifs_info *c) 55 { 56 if (ubifs_compr_present(c, UBIFS_COMPR_LZO)) 57 return UBIFS_COMPR_LZO; 58 59 if (ubifs_compr_present(c, UBIFS_COMPR_ZLIB)) 60 return UBIFS_COMPR_ZLIB; 61 62 return UBIFS_COMPR_NONE; 63 } 64 65 /** 66 * create_default_filesystem - format empty UBI volume. 67 * @c: UBIFS file-system description object 68 * 69 * This function creates default empty file-system. Returns zero in case of 70 * success and a negative error code in case of failure. 71 */ 72 static int create_default_filesystem(struct ubifs_info *c) 73 { 74 struct ubifs_sb_node *sup; 75 struct ubifs_mst_node *mst; 76 struct ubifs_idx_node *idx; 77 struct ubifs_branch *br; 78 struct ubifs_ino_node *ino; 79 struct ubifs_cs_node *cs; 80 union ubifs_key key; 81 int err, tmp, jnl_lebs, log_lebs, max_buds, main_lebs, main_first; 82 int lpt_lebs, lpt_first, orph_lebs, big_lpt, ino_waste, sup_flags = 0; 83 int min_leb_cnt = UBIFS_MIN_LEB_CNT; 84 int idx_node_size; 85 long long tmp64, main_bytes; 86 __le64 tmp_le64; 87 struct timespec64 ts; 88 u8 hash[UBIFS_HASH_ARR_SZ]; 89 u8 hash_lpt[UBIFS_HASH_ARR_SZ]; 90 91 /* Some functions called from here depend on the @c->key_len filed */ 92 c->key_len = UBIFS_SK_LEN; 93 94 /* 95 * First of all, we have to calculate default file-system geometry - 96 * log size, journal size, etc. 97 */ 98 if (c->leb_cnt < 0x7FFFFFFF / DEFAULT_JNL_PERCENT) 99 /* We can first multiply then divide and have no overflow */ 100 jnl_lebs = c->leb_cnt * DEFAULT_JNL_PERCENT / 100; 101 else 102 jnl_lebs = (c->leb_cnt / 100) * DEFAULT_JNL_PERCENT; 103 104 if (jnl_lebs < UBIFS_MIN_JNL_LEBS) 105 jnl_lebs = UBIFS_MIN_JNL_LEBS; 106 if (jnl_lebs * c->leb_size > DEFAULT_MAX_JNL) 107 jnl_lebs = DEFAULT_MAX_JNL / c->leb_size; 108 109 /* 110 * The log should be large enough to fit reference nodes for all bud 111 * LEBs. Because buds do not have to start from the beginning of LEBs 112 * (half of the LEB may contain committed data), the log should 113 * generally be larger, make it twice as large. 114 */ 115 tmp = 2 * (c->ref_node_alsz * jnl_lebs) + c->leb_size - 1; 116 log_lebs = tmp / c->leb_size; 117 /* Plus one LEB reserved for commit */ 118 log_lebs += 1; 119 if (c->leb_cnt - min_leb_cnt > 8) { 120 /* And some extra space to allow writes while committing */ 121 log_lebs += 1; 122 min_leb_cnt += 1; 123 } 124 125 max_buds = jnl_lebs - log_lebs; 126 if (max_buds < UBIFS_MIN_BUD_LEBS) 127 max_buds = UBIFS_MIN_BUD_LEBS; 128 129 /* 130 * Orphan nodes are stored in a separate area. One node can store a lot 131 * of orphan inode numbers, but when new orphan comes we just add a new 132 * orphan node. At some point the nodes are consolidated into one 133 * orphan node. 134 */ 135 orph_lebs = UBIFS_MIN_ORPH_LEBS; 136 if (c->leb_cnt - min_leb_cnt > 1) 137 /* 138 * For debugging purposes it is better to have at least 2 139 * orphan LEBs, because the orphan subsystem would need to do 140 * consolidations and would be stressed more. 141 */ 142 orph_lebs += 1; 143 144 main_lebs = c->leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS - log_lebs; 145 main_lebs -= orph_lebs; 146 147 lpt_first = UBIFS_LOG_LNUM + log_lebs; 148 c->lsave_cnt = DEFAULT_LSAVE_CNT; 149 c->max_leb_cnt = c->leb_cnt; 150 err = ubifs_create_dflt_lpt(c, &main_lebs, lpt_first, &lpt_lebs, 151 &big_lpt, hash_lpt); 152 if (err) 153 return err; 154 155 dbg_gen("LEB Properties Tree created (LEBs %d-%d)", lpt_first, 156 lpt_first + lpt_lebs - 1); 157 158 main_first = c->leb_cnt - main_lebs; 159 160 sup = kzalloc(ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size), GFP_KERNEL); 161 mst = kzalloc(c->mst_node_alsz, GFP_KERNEL); 162 idx_node_size = ubifs_idx_node_sz(c, 1); 163 idx = kzalloc(ALIGN(idx_node_size, c->min_io_size), GFP_KERNEL); 164 ino = kzalloc(ALIGN(UBIFS_INO_NODE_SZ, c->min_io_size), GFP_KERNEL); 165 cs = kzalloc(ALIGN(UBIFS_CS_NODE_SZ, c->min_io_size), GFP_KERNEL); 166 167 if (!sup || !mst || !idx || !ino || !cs) { 168 err = -ENOMEM; 169 goto out; 170 } 171 172 /* Create default superblock */ 173 174 tmp64 = (long long)max_buds * c->leb_size; 175 if (big_lpt) 176 sup_flags |= UBIFS_FLG_BIGLPT; 177 sup_flags |= UBIFS_FLG_DOUBLE_HASH; 178 179 if (ubifs_authenticated(c)) { 180 sup_flags |= UBIFS_FLG_AUTHENTICATION; 181 sup->hash_algo = cpu_to_le16(c->auth_hash_algo); 182 err = ubifs_hmac_wkm(c, sup->hmac_wkm); 183 if (err) 184 goto out; 185 } else { 186 sup->hash_algo = cpu_to_le16(0xffff); 187 } 188 189 sup->ch.node_type = UBIFS_SB_NODE; 190 sup->key_hash = UBIFS_KEY_HASH_R5; 191 sup->flags = cpu_to_le32(sup_flags); 192 sup->min_io_size = cpu_to_le32(c->min_io_size); 193 sup->leb_size = cpu_to_le32(c->leb_size); 194 sup->leb_cnt = cpu_to_le32(c->leb_cnt); 195 sup->max_leb_cnt = cpu_to_le32(c->max_leb_cnt); 196 sup->max_bud_bytes = cpu_to_le64(tmp64); 197 sup->log_lebs = cpu_to_le32(log_lebs); 198 sup->lpt_lebs = cpu_to_le32(lpt_lebs); 199 sup->orph_lebs = cpu_to_le32(orph_lebs); 200 sup->jhead_cnt = cpu_to_le32(DEFAULT_JHEADS_CNT); 201 sup->fanout = cpu_to_le32(DEFAULT_FANOUT); 202 sup->lsave_cnt = cpu_to_le32(c->lsave_cnt); 203 sup->fmt_version = cpu_to_le32(UBIFS_FORMAT_VERSION); 204 sup->time_gran = cpu_to_le32(DEFAULT_TIME_GRAN); 205 if (c->mount_opts.override_compr) 206 sup->default_compr = cpu_to_le16(c->mount_opts.compr_type); 207 else 208 sup->default_compr = cpu_to_le16(get_default_compressor(c)); 209 210 generate_random_uuid(sup->uuid); 211 212 main_bytes = (long long)main_lebs * c->leb_size; 213 tmp64 = div_u64(main_bytes * DEFAULT_RP_PERCENT, 100); 214 if (tmp64 > DEFAULT_MAX_RP_SIZE) 215 tmp64 = DEFAULT_MAX_RP_SIZE; 216 sup->rp_size = cpu_to_le64(tmp64); 217 sup->ro_compat_version = cpu_to_le32(UBIFS_RO_COMPAT_VERSION); 218 219 dbg_gen("default superblock created at LEB 0:0"); 220 221 /* Create default master node */ 222 223 mst->ch.node_type = UBIFS_MST_NODE; 224 mst->log_lnum = cpu_to_le32(UBIFS_LOG_LNUM); 225 mst->highest_inum = cpu_to_le64(UBIFS_FIRST_INO); 226 mst->cmt_no = 0; 227 mst->root_lnum = cpu_to_le32(main_first + DEFAULT_IDX_LEB); 228 mst->root_offs = 0; 229 tmp = ubifs_idx_node_sz(c, 1); 230 mst->root_len = cpu_to_le32(tmp); 231 mst->gc_lnum = cpu_to_le32(main_first + DEFAULT_GC_LEB); 232 mst->ihead_lnum = cpu_to_le32(main_first + DEFAULT_IDX_LEB); 233 mst->ihead_offs = cpu_to_le32(ALIGN(tmp, c->min_io_size)); 234 mst->index_size = cpu_to_le64(ALIGN(tmp, 8)); 235 mst->lpt_lnum = cpu_to_le32(c->lpt_lnum); 236 mst->lpt_offs = cpu_to_le32(c->lpt_offs); 237 mst->nhead_lnum = cpu_to_le32(c->nhead_lnum); 238 mst->nhead_offs = cpu_to_le32(c->nhead_offs); 239 mst->ltab_lnum = cpu_to_le32(c->ltab_lnum); 240 mst->ltab_offs = cpu_to_le32(c->ltab_offs); 241 mst->lsave_lnum = cpu_to_le32(c->lsave_lnum); 242 mst->lsave_offs = cpu_to_le32(c->lsave_offs); 243 mst->lscan_lnum = cpu_to_le32(main_first); 244 mst->empty_lebs = cpu_to_le32(main_lebs - 2); 245 mst->idx_lebs = cpu_to_le32(1); 246 mst->leb_cnt = cpu_to_le32(c->leb_cnt); 247 ubifs_copy_hash(c, hash_lpt, mst->hash_lpt); 248 249 /* Calculate lprops statistics */ 250 tmp64 = main_bytes; 251 tmp64 -= ALIGN(ubifs_idx_node_sz(c, 1), c->min_io_size); 252 tmp64 -= ALIGN(UBIFS_INO_NODE_SZ, c->min_io_size); 253 mst->total_free = cpu_to_le64(tmp64); 254 255 tmp64 = ALIGN(ubifs_idx_node_sz(c, 1), c->min_io_size); 256 ino_waste = ALIGN(UBIFS_INO_NODE_SZ, c->min_io_size) - 257 UBIFS_INO_NODE_SZ; 258 tmp64 += ino_waste; 259 tmp64 -= ALIGN(ubifs_idx_node_sz(c, 1), 8); 260 mst->total_dirty = cpu_to_le64(tmp64); 261 262 /* The indexing LEB does not contribute to dark space */ 263 tmp64 = ((long long)(c->main_lebs - 1) * c->dark_wm); 264 mst->total_dark = cpu_to_le64(tmp64); 265 266 mst->total_used = cpu_to_le64(UBIFS_INO_NODE_SZ); 267 268 dbg_gen("default master node created at LEB %d:0", UBIFS_MST_LNUM); 269 270 /* Create the root indexing node */ 271 272 c->key_fmt = UBIFS_SIMPLE_KEY_FMT; 273 c->key_hash = key_r5_hash; 274 275 idx->ch.node_type = UBIFS_IDX_NODE; 276 idx->child_cnt = cpu_to_le16(1); 277 ino_key_init(c, &key, UBIFS_ROOT_INO); 278 br = ubifs_idx_branch(c, idx, 0); 279 key_write_idx(c, &key, &br->key); 280 br->lnum = cpu_to_le32(main_first + DEFAULT_DATA_LEB); 281 br->len = cpu_to_le32(UBIFS_INO_NODE_SZ); 282 283 dbg_gen("default root indexing node created LEB %d:0", 284 main_first + DEFAULT_IDX_LEB); 285 286 /* Create default root inode */ 287 288 ino_key_init_flash(c, &ino->key, UBIFS_ROOT_INO); 289 ino->ch.node_type = UBIFS_INO_NODE; 290 ino->creat_sqnum = cpu_to_le64(++c->max_sqnum); 291 ino->nlink = cpu_to_le32(2); 292 293 ktime_get_coarse_real_ts64(&ts); 294 tmp_le64 = cpu_to_le64(ts.tv_sec); 295 ino->atime_sec = tmp_le64; 296 ino->ctime_sec = tmp_le64; 297 ino->mtime_sec = tmp_le64; 298 ino->atime_nsec = 0; 299 ino->ctime_nsec = 0; 300 ino->mtime_nsec = 0; 301 ino->mode = cpu_to_le32(S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO); 302 ino->size = cpu_to_le64(UBIFS_INO_NODE_SZ); 303 304 /* Set compression enabled by default */ 305 ino->flags = cpu_to_le32(UBIFS_COMPR_FL); 306 307 dbg_gen("root inode created at LEB %d:0", 308 main_first + DEFAULT_DATA_LEB); 309 310 /* 311 * The first node in the log has to be the commit start node. This is 312 * always the case during normal file-system operation. Write a fake 313 * commit start node to the log. 314 */ 315 316 cs->ch.node_type = UBIFS_CS_NODE; 317 318 err = ubifs_write_node_hmac(c, sup, UBIFS_SB_NODE_SZ, 0, 0, 319 offsetof(struct ubifs_sb_node, hmac)); 320 if (err) 321 goto out; 322 323 err = ubifs_write_node(c, ino, UBIFS_INO_NODE_SZ, 324 main_first + DEFAULT_DATA_LEB, 0); 325 if (err) 326 goto out; 327 328 ubifs_node_calc_hash(c, ino, hash); 329 ubifs_copy_hash(c, hash, ubifs_branch_hash(c, br)); 330 331 err = ubifs_write_node(c, idx, idx_node_size, main_first + DEFAULT_IDX_LEB, 0); 332 if (err) 333 goto out; 334 335 ubifs_node_calc_hash(c, idx, hash); 336 ubifs_copy_hash(c, hash, mst->hash_root_idx); 337 338 err = ubifs_write_node_hmac(c, mst, UBIFS_MST_NODE_SZ, UBIFS_MST_LNUM, 0, 339 offsetof(struct ubifs_mst_node, hmac)); 340 if (err) 341 goto out; 342 343 err = ubifs_write_node_hmac(c, mst, UBIFS_MST_NODE_SZ, UBIFS_MST_LNUM + 1, 344 0, offsetof(struct ubifs_mst_node, hmac)); 345 if (err) 346 goto out; 347 348 err = ubifs_write_node(c, cs, UBIFS_CS_NODE_SZ, UBIFS_LOG_LNUM, 0); 349 if (err) 350 goto out; 351 352 ubifs_msg(c, "default file-system created"); 353 354 err = 0; 355 out: 356 kfree(sup); 357 kfree(mst); 358 kfree(idx); 359 kfree(ino); 360 kfree(cs); 361 362 return err; 363 } 364 365 /** 366 * validate_sb - validate superblock node. 367 * @c: UBIFS file-system description object 368 * @sup: superblock node 369 * 370 * This function validates superblock node @sup. Since most of data was read 371 * from the superblock and stored in @c, the function validates fields in @c 372 * instead. Returns zero in case of success and %-EINVAL in case of validation 373 * failure. 374 */ 375 static int validate_sb(struct ubifs_info *c, struct ubifs_sb_node *sup) 376 { 377 long long max_bytes; 378 int err = 1, min_leb_cnt; 379 380 if (!c->key_hash) { 381 err = 2; 382 goto failed; 383 } 384 385 if (sup->key_fmt != UBIFS_SIMPLE_KEY_FMT) { 386 err = 3; 387 goto failed; 388 } 389 390 if (le32_to_cpu(sup->min_io_size) != c->min_io_size) { 391 ubifs_err(c, "min. I/O unit mismatch: %d in superblock, %d real", 392 le32_to_cpu(sup->min_io_size), c->min_io_size); 393 goto failed; 394 } 395 396 if (le32_to_cpu(sup->leb_size) != c->leb_size) { 397 ubifs_err(c, "LEB size mismatch: %d in superblock, %d real", 398 le32_to_cpu(sup->leb_size), c->leb_size); 399 goto failed; 400 } 401 402 if (c->log_lebs < UBIFS_MIN_LOG_LEBS || 403 c->lpt_lebs < UBIFS_MIN_LPT_LEBS || 404 c->orph_lebs < UBIFS_MIN_ORPH_LEBS || 405 c->main_lebs < UBIFS_MIN_MAIN_LEBS) { 406 err = 4; 407 goto failed; 408 } 409 410 /* 411 * Calculate minimum allowed amount of main area LEBs. This is very 412 * similar to %UBIFS_MIN_LEB_CNT, but we take into account real what we 413 * have just read from the superblock. 414 */ 415 min_leb_cnt = UBIFS_SB_LEBS + UBIFS_MST_LEBS + c->log_lebs; 416 min_leb_cnt += c->lpt_lebs + c->orph_lebs + c->jhead_cnt + 6; 417 418 if (c->leb_cnt < min_leb_cnt || c->leb_cnt > c->vi.size) { 419 ubifs_err(c, "bad LEB count: %d in superblock, %d on UBI volume, %d minimum required", 420 c->leb_cnt, c->vi.size, min_leb_cnt); 421 goto failed; 422 } 423 424 if (c->max_leb_cnt < c->leb_cnt) { 425 ubifs_err(c, "max. LEB count %d less than LEB count %d", 426 c->max_leb_cnt, c->leb_cnt); 427 goto failed; 428 } 429 430 if (c->main_lebs < UBIFS_MIN_MAIN_LEBS) { 431 ubifs_err(c, "too few main LEBs count %d, must be at least %d", 432 c->main_lebs, UBIFS_MIN_MAIN_LEBS); 433 goto failed; 434 } 435 436 max_bytes = (long long)c->leb_size * UBIFS_MIN_BUD_LEBS; 437 if (c->max_bud_bytes < max_bytes) { 438 ubifs_err(c, "too small journal (%lld bytes), must be at least %lld bytes", 439 c->max_bud_bytes, max_bytes); 440 goto failed; 441 } 442 443 max_bytes = (long long)c->leb_size * c->main_lebs; 444 if (c->max_bud_bytes > max_bytes) { 445 ubifs_err(c, "too large journal size (%lld bytes), only %lld bytes available in the main area", 446 c->max_bud_bytes, max_bytes); 447 goto failed; 448 } 449 450 if (c->jhead_cnt < NONDATA_JHEADS_CNT + 1 || 451 c->jhead_cnt > NONDATA_JHEADS_CNT + UBIFS_MAX_JHEADS) { 452 err = 9; 453 goto failed; 454 } 455 456 if (c->fanout < UBIFS_MIN_FANOUT || 457 ubifs_idx_node_sz(c, c->fanout) > c->leb_size) { 458 err = 10; 459 goto failed; 460 } 461 462 if (c->lsave_cnt < 0 || (c->lsave_cnt > DEFAULT_LSAVE_CNT && 463 c->lsave_cnt > c->max_leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS - 464 c->log_lebs - c->lpt_lebs - c->orph_lebs)) { 465 err = 11; 466 goto failed; 467 } 468 469 if (UBIFS_SB_LEBS + UBIFS_MST_LEBS + c->log_lebs + c->lpt_lebs + 470 c->orph_lebs + c->main_lebs != c->leb_cnt) { 471 err = 12; 472 goto failed; 473 } 474 475 if (c->default_compr >= UBIFS_COMPR_TYPES_CNT) { 476 err = 13; 477 goto failed; 478 } 479 480 if (c->rp_size < 0 || max_bytes < c->rp_size) { 481 err = 14; 482 goto failed; 483 } 484 485 if (le32_to_cpu(sup->time_gran) > 1000000000 || 486 le32_to_cpu(sup->time_gran) < 1) { 487 err = 15; 488 goto failed; 489 } 490 491 if (!c->double_hash && c->fmt_version >= 5) { 492 err = 16; 493 goto failed; 494 } 495 496 if (c->encrypted && c->fmt_version < 5) { 497 err = 17; 498 goto failed; 499 } 500 501 return 0; 502 503 failed: 504 ubifs_err(c, "bad superblock, error %d", err); 505 ubifs_dump_node(c, sup); 506 return -EINVAL; 507 } 508 509 /** 510 * ubifs_read_sb_node - read superblock node. 511 * @c: UBIFS file-system description object 512 * 513 * This function returns a pointer to the superblock node or a negative error 514 * code. Note, the user of this function is responsible of kfree()'ing the 515 * returned superblock buffer. 516 */ 517 static struct ubifs_sb_node *ubifs_read_sb_node(struct ubifs_info *c) 518 { 519 struct ubifs_sb_node *sup; 520 int err; 521 522 sup = kmalloc(ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size), GFP_NOFS); 523 if (!sup) 524 return ERR_PTR(-ENOMEM); 525 526 err = ubifs_read_node(c, sup, UBIFS_SB_NODE, UBIFS_SB_NODE_SZ, 527 UBIFS_SB_LNUM, 0); 528 if (err) { 529 kfree(sup); 530 return ERR_PTR(err); 531 } 532 533 return sup; 534 } 535 536 static int authenticate_sb_node(struct ubifs_info *c, 537 const struct ubifs_sb_node *sup) 538 { 539 unsigned int sup_flags = le32_to_cpu(sup->flags); 540 u8 hmac_wkm[UBIFS_HMAC_ARR_SZ]; 541 int authenticated = !!(sup_flags & UBIFS_FLG_AUTHENTICATION); 542 int hash_algo; 543 int err; 544 545 if (c->authenticated && !authenticated) { 546 ubifs_err(c, "authenticated FS forced, but found FS without authentication"); 547 return -EINVAL; 548 } 549 550 if (!c->authenticated && authenticated) { 551 ubifs_err(c, "authenticated FS found, but no key given"); 552 return -EINVAL; 553 } 554 555 ubifs_msg(c, "Mounting in %sauthenticated mode", 556 c->authenticated ? "" : "un"); 557 558 if (!c->authenticated) 559 return 0; 560 561 if (!IS_ENABLED(CONFIG_UBIFS_FS_AUTHENTICATION)) 562 return -EOPNOTSUPP; 563 564 hash_algo = le16_to_cpu(sup->hash_algo); 565 if (hash_algo >= HASH_ALGO__LAST) { 566 ubifs_err(c, "superblock uses unknown hash algo %d", 567 hash_algo); 568 return -EINVAL; 569 } 570 571 if (strcmp(hash_algo_name[hash_algo], c->auth_hash_name)) { 572 ubifs_err(c, "This filesystem uses %s for hashing," 573 " but %s is specified", hash_algo_name[hash_algo], 574 c->auth_hash_name); 575 return -EINVAL; 576 } 577 578 /* 579 * The super block node can either be authenticated by a HMAC or 580 * by a signature in a ubifs_sig_node directly following the 581 * super block node to support offline image creation. 582 */ 583 if (ubifs_hmac_zero(c, sup->hmac)) { 584 err = ubifs_sb_verify_signature(c, sup); 585 } else { 586 err = ubifs_hmac_wkm(c, hmac_wkm); 587 if (err) 588 return err; 589 if (ubifs_check_hmac(c, hmac_wkm, sup->hmac_wkm)) { 590 ubifs_err(c, "provided key does not fit"); 591 return -ENOKEY; 592 } 593 err = ubifs_node_verify_hmac(c, sup, sizeof(*sup), 594 offsetof(struct ubifs_sb_node, 595 hmac)); 596 } 597 598 if (err) 599 ubifs_err(c, "Failed to authenticate superblock: %d", err); 600 601 return err; 602 } 603 604 /** 605 * ubifs_write_sb_node - write superblock node. 606 * @c: UBIFS file-system description object 607 * @sup: superblock node read with 'ubifs_read_sb_node()' 608 * 609 * This function returns %0 on success and a negative error code on failure. 610 */ 611 int ubifs_write_sb_node(struct ubifs_info *c, struct ubifs_sb_node *sup) 612 { 613 int len = ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size); 614 int err; 615 616 err = ubifs_prepare_node_hmac(c, sup, UBIFS_SB_NODE_SZ, 617 offsetof(struct ubifs_sb_node, hmac), 1); 618 if (err) 619 return err; 620 621 return ubifs_leb_change(c, UBIFS_SB_LNUM, sup, len); 622 } 623 624 /** 625 * ubifs_read_superblock - read superblock. 626 * @c: UBIFS file-system description object 627 * 628 * This function finds, reads and checks the superblock. If an empty UBI volume 629 * is being mounted, this function creates default superblock. Returns zero in 630 * case of success, and a negative error code in case of failure. 631 */ 632 int ubifs_read_superblock(struct ubifs_info *c) 633 { 634 int err, sup_flags; 635 struct ubifs_sb_node *sup; 636 637 if (c->empty) { 638 err = create_default_filesystem(c); 639 if (err) 640 return err; 641 } 642 643 sup = ubifs_read_sb_node(c); 644 if (IS_ERR(sup)) 645 return PTR_ERR(sup); 646 647 c->sup_node = sup; 648 649 c->fmt_version = le32_to_cpu(sup->fmt_version); 650 c->ro_compat_version = le32_to_cpu(sup->ro_compat_version); 651 652 /* 653 * The software supports all previous versions but not future versions, 654 * due to the unavailability of time-travelling equipment. 655 */ 656 if (c->fmt_version > UBIFS_FORMAT_VERSION) { 657 ubifs_assert(c, !c->ro_media || c->ro_mount); 658 if (!c->ro_mount || 659 c->ro_compat_version > UBIFS_RO_COMPAT_VERSION) { 660 ubifs_err(c, "on-flash format version is w%d/r%d, but software only supports up to version w%d/r%d", 661 c->fmt_version, c->ro_compat_version, 662 UBIFS_FORMAT_VERSION, 663 UBIFS_RO_COMPAT_VERSION); 664 if (c->ro_compat_version <= UBIFS_RO_COMPAT_VERSION) { 665 ubifs_msg(c, "only R/O mounting is possible"); 666 err = -EROFS; 667 } else 668 err = -EINVAL; 669 goto out; 670 } 671 672 /* 673 * The FS is mounted R/O, and the media format is 674 * R/O-compatible with the UBIFS implementation, so we can 675 * mount. 676 */ 677 c->rw_incompat = 1; 678 } 679 680 if (c->fmt_version < 3) { 681 ubifs_err(c, "on-flash format version %d is not supported", 682 c->fmt_version); 683 err = -EINVAL; 684 goto out; 685 } 686 687 switch (sup->key_hash) { 688 case UBIFS_KEY_HASH_R5: 689 c->key_hash = key_r5_hash; 690 c->key_hash_type = UBIFS_KEY_HASH_R5; 691 break; 692 693 case UBIFS_KEY_HASH_TEST: 694 c->key_hash = key_test_hash; 695 c->key_hash_type = UBIFS_KEY_HASH_TEST; 696 break; 697 } 698 699 c->key_fmt = sup->key_fmt; 700 701 switch (c->key_fmt) { 702 case UBIFS_SIMPLE_KEY_FMT: 703 c->key_len = UBIFS_SK_LEN; 704 break; 705 default: 706 ubifs_err(c, "unsupported key format"); 707 err = -EINVAL; 708 goto out; 709 } 710 711 c->leb_cnt = le32_to_cpu(sup->leb_cnt); 712 c->max_leb_cnt = le32_to_cpu(sup->max_leb_cnt); 713 c->max_bud_bytes = le64_to_cpu(sup->max_bud_bytes); 714 c->log_lebs = le32_to_cpu(sup->log_lebs); 715 c->lpt_lebs = le32_to_cpu(sup->lpt_lebs); 716 c->orph_lebs = le32_to_cpu(sup->orph_lebs); 717 c->jhead_cnt = le32_to_cpu(sup->jhead_cnt) + NONDATA_JHEADS_CNT; 718 c->fanout = le32_to_cpu(sup->fanout); 719 c->lsave_cnt = le32_to_cpu(sup->lsave_cnt); 720 c->rp_size = le64_to_cpu(sup->rp_size); 721 c->rp_uid = make_kuid(&init_user_ns, le32_to_cpu(sup->rp_uid)); 722 c->rp_gid = make_kgid(&init_user_ns, le32_to_cpu(sup->rp_gid)); 723 sup_flags = le32_to_cpu(sup->flags); 724 if (!c->mount_opts.override_compr) 725 c->default_compr = le16_to_cpu(sup->default_compr); 726 727 c->vfs_sb->s_time_gran = le32_to_cpu(sup->time_gran); 728 memcpy(&c->uuid, &sup->uuid, 16); 729 c->big_lpt = !!(sup_flags & UBIFS_FLG_BIGLPT); 730 c->space_fixup = !!(sup_flags & UBIFS_FLG_SPACE_FIXUP); 731 c->double_hash = !!(sup_flags & UBIFS_FLG_DOUBLE_HASH); 732 c->encrypted = !!(sup_flags & UBIFS_FLG_ENCRYPTION); 733 734 err = authenticate_sb_node(c, sup); 735 if (err) 736 goto out; 737 738 if ((sup_flags & ~UBIFS_FLG_MASK) != 0) { 739 ubifs_err(c, "Unknown feature flags found: %#x", 740 sup_flags & ~UBIFS_FLG_MASK); 741 err = -EINVAL; 742 goto out; 743 } 744 745 if (!IS_ENABLED(CONFIG_FS_ENCRYPTION) && c->encrypted) { 746 ubifs_err(c, "file system contains encrypted files but UBIFS" 747 " was built without crypto support."); 748 err = -EINVAL; 749 goto out; 750 } 751 752 /* Automatically increase file system size to the maximum size */ 753 if (c->leb_cnt < c->vi.size && c->leb_cnt < c->max_leb_cnt) { 754 int old_leb_cnt = c->leb_cnt; 755 756 c->leb_cnt = min_t(int, c->max_leb_cnt, c->vi.size); 757 sup->leb_cnt = cpu_to_le32(c->leb_cnt); 758 759 c->superblock_need_write = 1; 760 761 dbg_mnt("Auto resizing from %d LEBs to %d LEBs", 762 old_leb_cnt, c->leb_cnt); 763 } 764 765 c->log_bytes = (long long)c->log_lebs * c->leb_size; 766 c->log_last = UBIFS_LOG_LNUM + c->log_lebs - 1; 767 c->lpt_first = UBIFS_LOG_LNUM + c->log_lebs; 768 c->lpt_last = c->lpt_first + c->lpt_lebs - 1; 769 c->orph_first = c->lpt_last + 1; 770 c->orph_last = c->orph_first + c->orph_lebs - 1; 771 c->main_lebs = c->leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS; 772 c->main_lebs -= c->log_lebs + c->lpt_lebs + c->orph_lebs; 773 c->main_first = c->leb_cnt - c->main_lebs; 774 775 err = validate_sb(c, sup); 776 out: 777 return err; 778 } 779 780 /** 781 * fixup_leb - fixup/unmap an LEB containing free space. 782 * @c: UBIFS file-system description object 783 * @lnum: the LEB number to fix up 784 * @len: number of used bytes in LEB (starting at offset 0) 785 * 786 * This function reads the contents of the given LEB number @lnum, then fixes 787 * it up, so that empty min. I/O units in the end of LEB are actually erased on 788 * flash (rather than being just all-0xff real data). If the LEB is completely 789 * empty, it is simply unmapped. 790 */ 791 static int fixup_leb(struct ubifs_info *c, int lnum, int len) 792 { 793 int err; 794 795 ubifs_assert(c, len >= 0); 796 ubifs_assert(c, len % c->min_io_size == 0); 797 ubifs_assert(c, len < c->leb_size); 798 799 if (len == 0) { 800 dbg_mnt("unmap empty LEB %d", lnum); 801 return ubifs_leb_unmap(c, lnum); 802 } 803 804 dbg_mnt("fixup LEB %d, data len %d", lnum, len); 805 err = ubifs_leb_read(c, lnum, c->sbuf, 0, len, 1); 806 if (err) 807 return err; 808 809 return ubifs_leb_change(c, lnum, c->sbuf, len); 810 } 811 812 /** 813 * fixup_free_space - find & remap all LEBs containing free space. 814 * @c: UBIFS file-system description object 815 * 816 * This function walks through all LEBs in the filesystem and fiexes up those 817 * containing free/empty space. 818 */ 819 static int fixup_free_space(struct ubifs_info *c) 820 { 821 int lnum, err = 0; 822 struct ubifs_lprops *lprops; 823 824 ubifs_get_lprops(c); 825 826 /* Fixup LEBs in the master area */ 827 for (lnum = UBIFS_MST_LNUM; lnum < UBIFS_LOG_LNUM; lnum++) { 828 err = fixup_leb(c, lnum, c->mst_offs + c->mst_node_alsz); 829 if (err) 830 goto out; 831 } 832 833 /* Unmap unused log LEBs */ 834 lnum = ubifs_next_log_lnum(c, c->lhead_lnum); 835 while (lnum != c->ltail_lnum) { 836 err = fixup_leb(c, lnum, 0); 837 if (err) 838 goto out; 839 lnum = ubifs_next_log_lnum(c, lnum); 840 } 841 842 /* 843 * Fixup the log head which contains the only a CS node at the 844 * beginning. 845 */ 846 err = fixup_leb(c, c->lhead_lnum, 847 ALIGN(UBIFS_CS_NODE_SZ, c->min_io_size)); 848 if (err) 849 goto out; 850 851 /* Fixup LEBs in the LPT area */ 852 for (lnum = c->lpt_first; lnum <= c->lpt_last; lnum++) { 853 int free = c->ltab[lnum - c->lpt_first].free; 854 855 if (free > 0) { 856 err = fixup_leb(c, lnum, c->leb_size - free); 857 if (err) 858 goto out; 859 } 860 } 861 862 /* Unmap LEBs in the orphans area */ 863 for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) { 864 err = fixup_leb(c, lnum, 0); 865 if (err) 866 goto out; 867 } 868 869 /* Fixup LEBs in the main area */ 870 for (lnum = c->main_first; lnum < c->leb_cnt; lnum++) { 871 lprops = ubifs_lpt_lookup(c, lnum); 872 if (IS_ERR(lprops)) { 873 err = PTR_ERR(lprops); 874 goto out; 875 } 876 877 if (lprops->free > 0) { 878 err = fixup_leb(c, lnum, c->leb_size - lprops->free); 879 if (err) 880 goto out; 881 } 882 } 883 884 out: 885 ubifs_release_lprops(c); 886 return err; 887 } 888 889 /** 890 * ubifs_fixup_free_space - find & fix all LEBs with free space. 891 * @c: UBIFS file-system description object 892 * 893 * This function fixes up LEBs containing free space on first mount, if the 894 * appropriate flag was set when the FS was created. Each LEB with one or more 895 * empty min. I/O unit (i.e. free-space-count > 0) is re-written, to make sure 896 * the free space is actually erased. E.g., this is necessary for some NAND 897 * chips, since the free space may have been programmed like real "0xff" data 898 * (generating a non-0xff ECC), causing future writes to the not-really-erased 899 * NAND pages to behave badly. After the space is fixed up, the superblock flag 900 * is cleared, so that this is skipped for all future mounts. 901 */ 902 int ubifs_fixup_free_space(struct ubifs_info *c) 903 { 904 int err; 905 struct ubifs_sb_node *sup = c->sup_node; 906 907 ubifs_assert(c, c->space_fixup); 908 ubifs_assert(c, !c->ro_mount); 909 910 ubifs_msg(c, "start fixing up free space"); 911 912 err = fixup_free_space(c); 913 if (err) 914 return err; 915 916 /* Free-space fixup is no longer required */ 917 c->space_fixup = 0; 918 sup->flags &= cpu_to_le32(~UBIFS_FLG_SPACE_FIXUP); 919 920 c->superblock_need_write = 1; 921 922 ubifs_msg(c, "free space fixup complete"); 923 return err; 924 } 925 926 int ubifs_enable_encryption(struct ubifs_info *c) 927 { 928 int err; 929 struct ubifs_sb_node *sup = c->sup_node; 930 931 if (!IS_ENABLED(CONFIG_FS_ENCRYPTION)) 932 return -EOPNOTSUPP; 933 934 if (c->encrypted) 935 return 0; 936 937 if (c->ro_mount || c->ro_media) 938 return -EROFS; 939 940 if (c->fmt_version < 5) { 941 ubifs_err(c, "on-flash format version 5 is needed for encryption"); 942 return -EINVAL; 943 } 944 945 sup->flags |= cpu_to_le32(UBIFS_FLG_ENCRYPTION); 946 947 err = ubifs_write_sb_node(c, sup); 948 if (!err) 949 c->encrypted = 1; 950 951 return err; 952 } 953