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 /* This file implements reading and writing the master node */ 12 13 #include "ubifs.h" 14 15 /** 16 * ubifs_compare_master_node - compare two UBIFS master nodes 17 * @c: UBIFS file-system description object 18 * @m1: the first node 19 * @m2: the second node 20 * 21 * This function compares two UBIFS master nodes. Returns 0 if they are equal 22 * and nonzero if not. 23 */ 24 int ubifs_compare_master_node(struct ubifs_info *c, void *m1, void *m2) 25 { 26 int ret; 27 int behind; 28 int hmac_offs = offsetof(struct ubifs_mst_node, hmac); 29 30 /* 31 * Do not compare the common node header since the sequence number and 32 * hence the CRC are different. 33 */ 34 ret = memcmp(m1 + UBIFS_CH_SZ, m2 + UBIFS_CH_SZ, 35 hmac_offs - UBIFS_CH_SZ); 36 if (ret) 37 return ret; 38 39 /* 40 * Do not compare the embedded HMAC aswell which also must be different 41 * due to the different common node header. 42 */ 43 behind = hmac_offs + UBIFS_MAX_HMAC_LEN; 44 45 if (UBIFS_MST_NODE_SZ > behind) 46 return memcmp(m1 + behind, m2 + behind, UBIFS_MST_NODE_SZ - behind); 47 48 return 0; 49 } 50 51 /* mst_node_check_hash - Check hash of a master node 52 * @c: UBIFS file-system description object 53 * @mst: The master node 54 * @expected: The expected hash of the master node 55 * 56 * This checks the hash of a master node against a given expected hash. 57 * Note that we have two master nodes on a UBIFS image which have different 58 * sequence numbers and consequently different CRCs. To be able to match 59 * both master nodes we exclude the common node header containing the sequence 60 * number and CRC from the hash. 61 * 62 * Returns 0 if the hashes are equal, a negative error code otherwise. 63 */ 64 static int mst_node_check_hash(const struct ubifs_info *c, 65 const struct ubifs_mst_node *mst, 66 const u8 *expected) 67 { 68 u8 calc[UBIFS_MAX_HASH_LEN]; 69 const void *node = mst; 70 71 crypto_shash_tfm_digest(c->hash_tfm, node + sizeof(struct ubifs_ch), 72 UBIFS_MST_NODE_SZ - sizeof(struct ubifs_ch), 73 calc); 74 75 if (ubifs_check_hash(c, expected, calc)) 76 return -EPERM; 77 78 return 0; 79 } 80 81 /** 82 * scan_for_master - search the valid master node. 83 * @c: UBIFS file-system description object 84 * 85 * This function scans the master node LEBs and search for the latest master 86 * node. Returns zero in case of success, %-EUCLEAN if there master area is 87 * corrupted and requires recovery, and a negative error code in case of 88 * failure. 89 */ 90 static int scan_for_master(struct ubifs_info *c) 91 { 92 struct ubifs_scan_leb *sleb; 93 struct ubifs_scan_node *snod; 94 int lnum, offs = 0, nodes_cnt, err; 95 96 lnum = UBIFS_MST_LNUM; 97 98 sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1); 99 if (IS_ERR(sleb)) 100 return PTR_ERR(sleb); 101 nodes_cnt = sleb->nodes_cnt; 102 if (nodes_cnt > 0) { 103 snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node, 104 list); 105 if (snod->type != UBIFS_MST_NODE) 106 goto out_dump; 107 memcpy(c->mst_node, snod->node, snod->len); 108 offs = snod->offs; 109 } 110 ubifs_scan_destroy(sleb); 111 112 lnum += 1; 113 114 sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1); 115 if (IS_ERR(sleb)) 116 return PTR_ERR(sleb); 117 if (sleb->nodes_cnt != nodes_cnt) 118 goto out; 119 if (!sleb->nodes_cnt) 120 goto out; 121 snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node, list); 122 if (snod->type != UBIFS_MST_NODE) 123 goto out_dump; 124 if (snod->offs != offs) 125 goto out; 126 if (ubifs_compare_master_node(c, c->mst_node, snod->node)) 127 goto out; 128 129 c->mst_offs = offs; 130 ubifs_scan_destroy(sleb); 131 132 if (!ubifs_authenticated(c)) 133 return 0; 134 135 if (ubifs_hmac_zero(c, c->mst_node->hmac)) { 136 err = mst_node_check_hash(c, c->mst_node, 137 c->sup_node->hash_mst); 138 if (err) 139 ubifs_err(c, "Failed to verify master node hash"); 140 } else { 141 err = ubifs_node_verify_hmac(c, c->mst_node, 142 sizeof(struct ubifs_mst_node), 143 offsetof(struct ubifs_mst_node, hmac)); 144 if (err) 145 ubifs_err(c, "Failed to verify master node HMAC"); 146 } 147 148 if (err) 149 return -EPERM; 150 151 return 0; 152 153 out: 154 ubifs_scan_destroy(sleb); 155 return -EUCLEAN; 156 157 out_dump: 158 ubifs_err(c, "unexpected node type %d master LEB %d:%d", 159 snod->type, lnum, snod->offs); 160 ubifs_scan_destroy(sleb); 161 return -EINVAL; 162 } 163 164 /** 165 * validate_master - validate master node. 166 * @c: UBIFS file-system description object 167 * 168 * This function validates data which was read from master node. Returns zero 169 * if the data is all right and %-EINVAL if not. 170 */ 171 static int validate_master(const struct ubifs_info *c) 172 { 173 long long main_sz; 174 int err; 175 176 if (c->max_sqnum >= SQNUM_WATERMARK) { 177 err = 1; 178 goto out; 179 } 180 181 if (c->cmt_no >= c->max_sqnum) { 182 err = 2; 183 goto out; 184 } 185 186 if (c->highest_inum >= INUM_WATERMARK) { 187 err = 3; 188 goto out; 189 } 190 191 if (c->lhead_lnum < UBIFS_LOG_LNUM || 192 c->lhead_lnum >= UBIFS_LOG_LNUM + c->log_lebs || 193 c->lhead_offs < 0 || c->lhead_offs >= c->leb_size || 194 c->lhead_offs & (c->min_io_size - 1)) { 195 err = 4; 196 goto out; 197 } 198 199 if (c->zroot.lnum >= c->leb_cnt || c->zroot.lnum < c->main_first || 200 c->zroot.offs >= c->leb_size || c->zroot.offs & 7) { 201 err = 5; 202 goto out; 203 } 204 205 if (c->zroot.len < c->ranges[UBIFS_IDX_NODE].min_len || 206 c->zroot.len > c->ranges[UBIFS_IDX_NODE].max_len) { 207 err = 6; 208 goto out; 209 } 210 211 if (c->gc_lnum >= c->leb_cnt || c->gc_lnum < c->main_first) { 212 err = 7; 213 goto out; 214 } 215 216 if (c->ihead_lnum >= c->leb_cnt || c->ihead_lnum < c->main_first || 217 c->ihead_offs % c->min_io_size || c->ihead_offs < 0 || 218 c->ihead_offs > c->leb_size || c->ihead_offs & 7) { 219 err = 8; 220 goto out; 221 } 222 223 main_sz = (long long)c->main_lebs * c->leb_size; 224 if (c->bi.old_idx_sz & 7 || c->bi.old_idx_sz >= main_sz) { 225 err = 9; 226 goto out; 227 } 228 229 if (c->lpt_lnum < c->lpt_first || c->lpt_lnum > c->lpt_last || 230 c->lpt_offs < 0 || c->lpt_offs + c->nnode_sz > c->leb_size) { 231 err = 10; 232 goto out; 233 } 234 235 if (c->nhead_lnum < c->lpt_first || c->nhead_lnum > c->lpt_last || 236 c->nhead_offs < 0 || c->nhead_offs % c->min_io_size || 237 c->nhead_offs > c->leb_size) { 238 err = 11; 239 goto out; 240 } 241 242 if (c->ltab_lnum < c->lpt_first || c->ltab_lnum > c->lpt_last || 243 c->ltab_offs < 0 || 244 c->ltab_offs + c->ltab_sz > c->leb_size) { 245 err = 12; 246 goto out; 247 } 248 249 if (c->big_lpt && (c->lsave_lnum < c->lpt_first || 250 c->lsave_lnum > c->lpt_last || c->lsave_offs < 0 || 251 c->lsave_offs + c->lsave_sz > c->leb_size)) { 252 err = 13; 253 goto out; 254 } 255 256 if (c->lscan_lnum < c->main_first || c->lscan_lnum >= c->leb_cnt) { 257 err = 14; 258 goto out; 259 } 260 261 if (c->lst.empty_lebs < 0 || c->lst.empty_lebs > c->main_lebs - 2) { 262 err = 15; 263 goto out; 264 } 265 266 if (c->lst.idx_lebs < 0 || c->lst.idx_lebs > c->main_lebs - 1) { 267 err = 16; 268 goto out; 269 } 270 271 if (c->lst.total_free < 0 || c->lst.total_free > main_sz || 272 c->lst.total_free & 7) { 273 err = 17; 274 goto out; 275 } 276 277 if (c->lst.total_dirty < 0 || (c->lst.total_dirty & 7)) { 278 err = 18; 279 goto out; 280 } 281 282 if (c->lst.total_used < 0 || (c->lst.total_used & 7)) { 283 err = 19; 284 goto out; 285 } 286 287 if (c->lst.total_free + c->lst.total_dirty + 288 c->lst.total_used > main_sz) { 289 err = 20; 290 goto out; 291 } 292 293 if (c->lst.total_dead + c->lst.total_dark + 294 c->lst.total_used + c->bi.old_idx_sz > main_sz) { 295 err = 21; 296 goto out; 297 } 298 299 if (c->lst.total_dead < 0 || 300 c->lst.total_dead > c->lst.total_free + c->lst.total_dirty || 301 c->lst.total_dead & 7) { 302 err = 22; 303 goto out; 304 } 305 306 if (c->lst.total_dark < 0 || 307 c->lst.total_dark > c->lst.total_free + c->lst.total_dirty || 308 c->lst.total_dark & 7) { 309 err = 23; 310 goto out; 311 } 312 313 return 0; 314 315 out: 316 ubifs_err(c, "bad master node at offset %d error %d", c->mst_offs, err); 317 ubifs_dump_node(c, c->mst_node, c->mst_node_alsz); 318 return -EINVAL; 319 } 320 321 /** 322 * ubifs_read_master - read master node. 323 * @c: UBIFS file-system description object 324 * 325 * This function finds and reads the master node during file-system mount. If 326 * the flash is empty, it creates default master node as well. Returns zero in 327 * case of success and a negative error code in case of failure. 328 */ 329 int ubifs_read_master(struct ubifs_info *c) 330 { 331 int err, old_leb_cnt; 332 333 c->mst_node = kzalloc(c->mst_node_alsz, GFP_KERNEL); 334 if (!c->mst_node) 335 return -ENOMEM; 336 337 err = scan_for_master(c); 338 if (err) { 339 if (err == -EUCLEAN) 340 err = ubifs_recover_master_node(c); 341 if (err) 342 /* 343 * Note, we do not free 'c->mst_node' here because the 344 * unmount routine will take care of this. 345 */ 346 return err; 347 } 348 349 /* Make sure that the recovery flag is clear */ 350 c->mst_node->flags &= cpu_to_le32(~UBIFS_MST_RCVRY); 351 352 c->max_sqnum = le64_to_cpu(c->mst_node->ch.sqnum); 353 c->highest_inum = le64_to_cpu(c->mst_node->highest_inum); 354 c->cmt_no = le64_to_cpu(c->mst_node->cmt_no); 355 c->zroot.lnum = le32_to_cpu(c->mst_node->root_lnum); 356 c->zroot.offs = le32_to_cpu(c->mst_node->root_offs); 357 c->zroot.len = le32_to_cpu(c->mst_node->root_len); 358 c->lhead_lnum = le32_to_cpu(c->mst_node->log_lnum); 359 c->gc_lnum = le32_to_cpu(c->mst_node->gc_lnum); 360 c->ihead_lnum = le32_to_cpu(c->mst_node->ihead_lnum); 361 c->ihead_offs = le32_to_cpu(c->mst_node->ihead_offs); 362 c->bi.old_idx_sz = le64_to_cpu(c->mst_node->index_size); 363 c->lpt_lnum = le32_to_cpu(c->mst_node->lpt_lnum); 364 c->lpt_offs = le32_to_cpu(c->mst_node->lpt_offs); 365 c->nhead_lnum = le32_to_cpu(c->mst_node->nhead_lnum); 366 c->nhead_offs = le32_to_cpu(c->mst_node->nhead_offs); 367 c->ltab_lnum = le32_to_cpu(c->mst_node->ltab_lnum); 368 c->ltab_offs = le32_to_cpu(c->mst_node->ltab_offs); 369 c->lsave_lnum = le32_to_cpu(c->mst_node->lsave_lnum); 370 c->lsave_offs = le32_to_cpu(c->mst_node->lsave_offs); 371 c->lscan_lnum = le32_to_cpu(c->mst_node->lscan_lnum); 372 c->lst.empty_lebs = le32_to_cpu(c->mst_node->empty_lebs); 373 c->lst.idx_lebs = le32_to_cpu(c->mst_node->idx_lebs); 374 old_leb_cnt = le32_to_cpu(c->mst_node->leb_cnt); 375 c->lst.total_free = le64_to_cpu(c->mst_node->total_free); 376 c->lst.total_dirty = le64_to_cpu(c->mst_node->total_dirty); 377 c->lst.total_used = le64_to_cpu(c->mst_node->total_used); 378 c->lst.total_dead = le64_to_cpu(c->mst_node->total_dead); 379 c->lst.total_dark = le64_to_cpu(c->mst_node->total_dark); 380 381 ubifs_copy_hash(c, c->mst_node->hash_root_idx, c->zroot.hash); 382 383 c->calc_idx_sz = c->bi.old_idx_sz; 384 385 if (c->mst_node->flags & cpu_to_le32(UBIFS_MST_NO_ORPHS)) 386 c->no_orphs = 1; 387 388 if (old_leb_cnt != c->leb_cnt) { 389 /* The file system has been resized */ 390 int growth = c->leb_cnt - old_leb_cnt; 391 392 if (c->leb_cnt < old_leb_cnt || 393 c->leb_cnt < UBIFS_MIN_LEB_CNT) { 394 ubifs_err(c, "bad leb_cnt on master node"); 395 ubifs_dump_node(c, c->mst_node, c->mst_node_alsz); 396 return -EINVAL; 397 } 398 399 dbg_mnt("Auto resizing (master) from %d LEBs to %d LEBs", 400 old_leb_cnt, c->leb_cnt); 401 c->lst.empty_lebs += growth; 402 c->lst.total_free += growth * (long long)c->leb_size; 403 c->lst.total_dark += growth * (long long)c->dark_wm; 404 405 /* 406 * Reflect changes back onto the master node. N.B. the master 407 * node gets written immediately whenever mounting (or 408 * remounting) in read-write mode, so we do not need to write it 409 * here. 410 */ 411 c->mst_node->leb_cnt = cpu_to_le32(c->leb_cnt); 412 c->mst_node->empty_lebs = cpu_to_le32(c->lst.empty_lebs); 413 c->mst_node->total_free = cpu_to_le64(c->lst.total_free); 414 c->mst_node->total_dark = cpu_to_le64(c->lst.total_dark); 415 } 416 417 err = validate_master(c); 418 if (err) 419 return err; 420 421 err = dbg_old_index_check_init(c, &c->zroot); 422 423 return err; 424 } 425 426 /** 427 * ubifs_write_master - write master node. 428 * @c: UBIFS file-system description object 429 * 430 * This function writes the master node. Returns zero in case of success and a 431 * negative error code in case of failure. The master node is written twice to 432 * enable recovery. 433 */ 434 int ubifs_write_master(struct ubifs_info *c) 435 { 436 int err, lnum, offs, len; 437 438 ubifs_assert(c, !c->ro_media && !c->ro_mount); 439 if (c->ro_error) 440 return -EROFS; 441 442 lnum = UBIFS_MST_LNUM; 443 offs = c->mst_offs + c->mst_node_alsz; 444 len = UBIFS_MST_NODE_SZ; 445 446 if (offs + UBIFS_MST_NODE_SZ > c->leb_size) { 447 err = ubifs_leb_unmap(c, lnum); 448 if (err) 449 return err; 450 offs = 0; 451 } 452 453 c->mst_offs = offs; 454 c->mst_node->highest_inum = cpu_to_le64(c->highest_inum); 455 456 ubifs_copy_hash(c, c->zroot.hash, c->mst_node->hash_root_idx); 457 err = ubifs_write_node_hmac(c, c->mst_node, len, lnum, offs, 458 offsetof(struct ubifs_mst_node, hmac)); 459 if (err) 460 return err; 461 462 lnum += 1; 463 464 if (offs == 0) { 465 err = ubifs_leb_unmap(c, lnum); 466 if (err) 467 return err; 468 } 469 err = ubifs_write_node_hmac(c, c->mst_node, len, lnum, offs, 470 offsetof(struct ubifs_mst_node, hmac)); 471 472 return err; 473 } 474