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 SHASH_DESC_ON_STACK(shash, c->hash_tfm); 72 73 shash->tfm = c->hash_tfm; 74 75 crypto_shash_digest(shash, node + sizeof(struct ubifs_ch), 76 UBIFS_MST_NODE_SZ - sizeof(struct ubifs_ch), calc); 77 78 if (ubifs_check_hash(c, expected, calc)) 79 return -EPERM; 80 81 return 0; 82 } 83 84 /** 85 * scan_for_master - search the valid master node. 86 * @c: UBIFS file-system description object 87 * 88 * This function scans the master node LEBs and search for the latest master 89 * node. Returns zero in case of success, %-EUCLEAN if there master area is 90 * corrupted and requires recovery, and a negative error code in case of 91 * failure. 92 */ 93 static int scan_for_master(struct ubifs_info *c) 94 { 95 struct ubifs_scan_leb *sleb; 96 struct ubifs_scan_node *snod; 97 int lnum, offs = 0, nodes_cnt, err; 98 99 lnum = UBIFS_MST_LNUM; 100 101 sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1); 102 if (IS_ERR(sleb)) 103 return PTR_ERR(sleb); 104 nodes_cnt = sleb->nodes_cnt; 105 if (nodes_cnt > 0) { 106 snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node, 107 list); 108 if (snod->type != UBIFS_MST_NODE) 109 goto out_dump; 110 memcpy(c->mst_node, snod->node, snod->len); 111 offs = snod->offs; 112 } 113 ubifs_scan_destroy(sleb); 114 115 lnum += 1; 116 117 sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1); 118 if (IS_ERR(sleb)) 119 return PTR_ERR(sleb); 120 if (sleb->nodes_cnt != nodes_cnt) 121 goto out; 122 if (!sleb->nodes_cnt) 123 goto out; 124 snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node, list); 125 if (snod->type != UBIFS_MST_NODE) 126 goto out_dump; 127 if (snod->offs != offs) 128 goto out; 129 if (ubifs_compare_master_node(c, c->mst_node, snod->node)) 130 goto out; 131 132 c->mst_offs = offs; 133 ubifs_scan_destroy(sleb); 134 135 if (!ubifs_authenticated(c)) 136 return 0; 137 138 if (ubifs_hmac_zero(c, c->mst_node->hmac)) { 139 err = mst_node_check_hash(c, c->mst_node, 140 c->sup_node->hash_mst); 141 if (err) 142 ubifs_err(c, "Failed to verify master node hash"); 143 } else { 144 err = ubifs_node_verify_hmac(c, c->mst_node, 145 sizeof(struct ubifs_mst_node), 146 offsetof(struct ubifs_mst_node, hmac)); 147 if (err) 148 ubifs_err(c, "Failed to verify master node HMAC"); 149 } 150 151 if (err) 152 return -EPERM; 153 154 return 0; 155 156 out: 157 ubifs_scan_destroy(sleb); 158 return -EUCLEAN; 159 160 out_dump: 161 ubifs_err(c, "unexpected node type %d master LEB %d:%d", 162 snod->type, lnum, snod->offs); 163 ubifs_scan_destroy(sleb); 164 return -EINVAL; 165 } 166 167 /** 168 * validate_master - validate master node. 169 * @c: UBIFS file-system description object 170 * 171 * This function validates data which was read from master node. Returns zero 172 * if the data is all right and %-EINVAL if not. 173 */ 174 static int validate_master(const struct ubifs_info *c) 175 { 176 long long main_sz; 177 int err; 178 179 if (c->max_sqnum >= SQNUM_WATERMARK) { 180 err = 1; 181 goto out; 182 } 183 184 if (c->cmt_no >= c->max_sqnum) { 185 err = 2; 186 goto out; 187 } 188 189 if (c->highest_inum >= INUM_WATERMARK) { 190 err = 3; 191 goto out; 192 } 193 194 if (c->lhead_lnum < UBIFS_LOG_LNUM || 195 c->lhead_lnum >= UBIFS_LOG_LNUM + c->log_lebs || 196 c->lhead_offs < 0 || c->lhead_offs >= c->leb_size || 197 c->lhead_offs & (c->min_io_size - 1)) { 198 err = 4; 199 goto out; 200 } 201 202 if (c->zroot.lnum >= c->leb_cnt || c->zroot.lnum < c->main_first || 203 c->zroot.offs >= c->leb_size || c->zroot.offs & 7) { 204 err = 5; 205 goto out; 206 } 207 208 if (c->zroot.len < c->ranges[UBIFS_IDX_NODE].min_len || 209 c->zroot.len > c->ranges[UBIFS_IDX_NODE].max_len) { 210 err = 6; 211 goto out; 212 } 213 214 if (c->gc_lnum >= c->leb_cnt || c->gc_lnum < c->main_first) { 215 err = 7; 216 goto out; 217 } 218 219 if (c->ihead_lnum >= c->leb_cnt || c->ihead_lnum < c->main_first || 220 c->ihead_offs % c->min_io_size || c->ihead_offs < 0 || 221 c->ihead_offs > c->leb_size || c->ihead_offs & 7) { 222 err = 8; 223 goto out; 224 } 225 226 main_sz = (long long)c->main_lebs * c->leb_size; 227 if (c->bi.old_idx_sz & 7 || c->bi.old_idx_sz >= main_sz) { 228 err = 9; 229 goto out; 230 } 231 232 if (c->lpt_lnum < c->lpt_first || c->lpt_lnum > c->lpt_last || 233 c->lpt_offs < 0 || c->lpt_offs + c->nnode_sz > c->leb_size) { 234 err = 10; 235 goto out; 236 } 237 238 if (c->nhead_lnum < c->lpt_first || c->nhead_lnum > c->lpt_last || 239 c->nhead_offs < 0 || c->nhead_offs % c->min_io_size || 240 c->nhead_offs > c->leb_size) { 241 err = 11; 242 goto out; 243 } 244 245 if (c->ltab_lnum < c->lpt_first || c->ltab_lnum > c->lpt_last || 246 c->ltab_offs < 0 || 247 c->ltab_offs + c->ltab_sz > c->leb_size) { 248 err = 12; 249 goto out; 250 } 251 252 if (c->big_lpt && (c->lsave_lnum < c->lpt_first || 253 c->lsave_lnum > c->lpt_last || c->lsave_offs < 0 || 254 c->lsave_offs + c->lsave_sz > c->leb_size)) { 255 err = 13; 256 goto out; 257 } 258 259 if (c->lscan_lnum < c->main_first || c->lscan_lnum >= c->leb_cnt) { 260 err = 14; 261 goto out; 262 } 263 264 if (c->lst.empty_lebs < 0 || c->lst.empty_lebs > c->main_lebs - 2) { 265 err = 15; 266 goto out; 267 } 268 269 if (c->lst.idx_lebs < 0 || c->lst.idx_lebs > c->main_lebs - 1) { 270 err = 16; 271 goto out; 272 } 273 274 if (c->lst.total_free < 0 || c->lst.total_free > main_sz || 275 c->lst.total_free & 7) { 276 err = 17; 277 goto out; 278 } 279 280 if (c->lst.total_dirty < 0 || (c->lst.total_dirty & 7)) { 281 err = 18; 282 goto out; 283 } 284 285 if (c->lst.total_used < 0 || (c->lst.total_used & 7)) { 286 err = 19; 287 goto out; 288 } 289 290 if (c->lst.total_free + c->lst.total_dirty + 291 c->lst.total_used > main_sz) { 292 err = 20; 293 goto out; 294 } 295 296 if (c->lst.total_dead + c->lst.total_dark + 297 c->lst.total_used + c->bi.old_idx_sz > main_sz) { 298 err = 21; 299 goto out; 300 } 301 302 if (c->lst.total_dead < 0 || 303 c->lst.total_dead > c->lst.total_free + c->lst.total_dirty || 304 c->lst.total_dead & 7) { 305 err = 22; 306 goto out; 307 } 308 309 if (c->lst.total_dark < 0 || 310 c->lst.total_dark > c->lst.total_free + c->lst.total_dirty || 311 c->lst.total_dark & 7) { 312 err = 23; 313 goto out; 314 } 315 316 return 0; 317 318 out: 319 ubifs_err(c, "bad master node at offset %d error %d", c->mst_offs, err); 320 ubifs_dump_node(c, c->mst_node); 321 return -EINVAL; 322 } 323 324 /** 325 * ubifs_read_master - read master node. 326 * @c: UBIFS file-system description object 327 * 328 * This function finds and reads the master node during file-system mount. If 329 * the flash is empty, it creates default master node as well. Returns zero in 330 * case of success and a negative error code in case of failure. 331 */ 332 int ubifs_read_master(struct ubifs_info *c) 333 { 334 int err, old_leb_cnt; 335 336 c->mst_node = kzalloc(c->mst_node_alsz, GFP_KERNEL); 337 if (!c->mst_node) 338 return -ENOMEM; 339 340 err = scan_for_master(c); 341 if (err) { 342 if (err == -EUCLEAN) 343 err = ubifs_recover_master_node(c); 344 if (err) 345 /* 346 * Note, we do not free 'c->mst_node' here because the 347 * unmount routine will take care of this. 348 */ 349 return err; 350 } 351 352 /* Make sure that the recovery flag is clear */ 353 c->mst_node->flags &= cpu_to_le32(~UBIFS_MST_RCVRY); 354 355 c->max_sqnum = le64_to_cpu(c->mst_node->ch.sqnum); 356 c->highest_inum = le64_to_cpu(c->mst_node->highest_inum); 357 c->cmt_no = le64_to_cpu(c->mst_node->cmt_no); 358 c->zroot.lnum = le32_to_cpu(c->mst_node->root_lnum); 359 c->zroot.offs = le32_to_cpu(c->mst_node->root_offs); 360 c->zroot.len = le32_to_cpu(c->mst_node->root_len); 361 c->lhead_lnum = le32_to_cpu(c->mst_node->log_lnum); 362 c->gc_lnum = le32_to_cpu(c->mst_node->gc_lnum); 363 c->ihead_lnum = le32_to_cpu(c->mst_node->ihead_lnum); 364 c->ihead_offs = le32_to_cpu(c->mst_node->ihead_offs); 365 c->bi.old_idx_sz = le64_to_cpu(c->mst_node->index_size); 366 c->lpt_lnum = le32_to_cpu(c->mst_node->lpt_lnum); 367 c->lpt_offs = le32_to_cpu(c->mst_node->lpt_offs); 368 c->nhead_lnum = le32_to_cpu(c->mst_node->nhead_lnum); 369 c->nhead_offs = le32_to_cpu(c->mst_node->nhead_offs); 370 c->ltab_lnum = le32_to_cpu(c->mst_node->ltab_lnum); 371 c->ltab_offs = le32_to_cpu(c->mst_node->ltab_offs); 372 c->lsave_lnum = le32_to_cpu(c->mst_node->lsave_lnum); 373 c->lsave_offs = le32_to_cpu(c->mst_node->lsave_offs); 374 c->lscan_lnum = le32_to_cpu(c->mst_node->lscan_lnum); 375 c->lst.empty_lebs = le32_to_cpu(c->mst_node->empty_lebs); 376 c->lst.idx_lebs = le32_to_cpu(c->mst_node->idx_lebs); 377 old_leb_cnt = le32_to_cpu(c->mst_node->leb_cnt); 378 c->lst.total_free = le64_to_cpu(c->mst_node->total_free); 379 c->lst.total_dirty = le64_to_cpu(c->mst_node->total_dirty); 380 c->lst.total_used = le64_to_cpu(c->mst_node->total_used); 381 c->lst.total_dead = le64_to_cpu(c->mst_node->total_dead); 382 c->lst.total_dark = le64_to_cpu(c->mst_node->total_dark); 383 384 ubifs_copy_hash(c, c->mst_node->hash_root_idx, c->zroot.hash); 385 386 c->calc_idx_sz = c->bi.old_idx_sz; 387 388 if (c->mst_node->flags & cpu_to_le32(UBIFS_MST_NO_ORPHS)) 389 c->no_orphs = 1; 390 391 if (old_leb_cnt != c->leb_cnt) { 392 /* The file system has been resized */ 393 int growth = c->leb_cnt - old_leb_cnt; 394 395 if (c->leb_cnt < old_leb_cnt || 396 c->leb_cnt < UBIFS_MIN_LEB_CNT) { 397 ubifs_err(c, "bad leb_cnt on master node"); 398 ubifs_dump_node(c, c->mst_node); 399 return -EINVAL; 400 } 401 402 dbg_mnt("Auto resizing (master) from %d LEBs to %d LEBs", 403 old_leb_cnt, c->leb_cnt); 404 c->lst.empty_lebs += growth; 405 c->lst.total_free += growth * (long long)c->leb_size; 406 c->lst.total_dark += growth * (long long)c->dark_wm; 407 408 /* 409 * Reflect changes back onto the master node. N.B. the master 410 * node gets written immediately whenever mounting (or 411 * remounting) in read-write mode, so we do not need to write it 412 * here. 413 */ 414 c->mst_node->leb_cnt = cpu_to_le32(c->leb_cnt); 415 c->mst_node->empty_lebs = cpu_to_le32(c->lst.empty_lebs); 416 c->mst_node->total_free = cpu_to_le64(c->lst.total_free); 417 c->mst_node->total_dark = cpu_to_le64(c->lst.total_dark); 418 } 419 420 err = validate_master(c); 421 if (err) 422 return err; 423 424 err = dbg_old_index_check_init(c, &c->zroot); 425 426 return err; 427 } 428 429 /** 430 * ubifs_write_master - write master node. 431 * @c: UBIFS file-system description object 432 * 433 * This function writes the master node. Returns zero in case of success and a 434 * negative error code in case of failure. The master node is written twice to 435 * enable recovery. 436 */ 437 int ubifs_write_master(struct ubifs_info *c) 438 { 439 int err, lnum, offs, len; 440 441 ubifs_assert(c, !c->ro_media && !c->ro_mount); 442 if (c->ro_error) 443 return -EROFS; 444 445 lnum = UBIFS_MST_LNUM; 446 offs = c->mst_offs + c->mst_node_alsz; 447 len = UBIFS_MST_NODE_SZ; 448 449 if (offs + UBIFS_MST_NODE_SZ > c->leb_size) { 450 err = ubifs_leb_unmap(c, lnum); 451 if (err) 452 return err; 453 offs = 0; 454 } 455 456 c->mst_offs = offs; 457 c->mst_node->highest_inum = cpu_to_le64(c->highest_inum); 458 459 ubifs_copy_hash(c, c->zroot.hash, c->mst_node->hash_root_idx); 460 err = ubifs_write_node_hmac(c, c->mst_node, len, lnum, offs, 461 offsetof(struct ubifs_mst_node, hmac)); 462 if (err) 463 return err; 464 465 lnum += 1; 466 467 if (offs == 0) { 468 err = ubifs_leb_unmap(c, lnum); 469 if (err) 470 return err; 471 } 472 err = ubifs_write_node_hmac(c, c->mst_node, len, lnum, offs, 473 offsetof(struct ubifs_mst_node, hmac)); 474 475 return err; 476 } 477