1 /* 2 * This file is part of UBIFS. 3 * 4 * Copyright (C) 2006-2008 Nokia Corporation. 5 * 6 * This program is free software; you can redistribute it and/or modify it 7 * under the terms of the GNU General Public License version 2 as published by 8 * the Free Software Foundation. 9 * 10 * This program is distributed in the hope that it will be useful, but WITHOUT 11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 13 * more details. 14 * 15 * You should have received a copy of the GNU General Public License along with 16 * this program; if not, write to the Free Software Foundation, Inc., 51 17 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 18 * 19 * Authors: Artem Bityutskiy (Битюцкий Артём) 20 * Adrian Hunter 21 */ 22 23 /* This file implements reading and writing the master node */ 24 25 #include "ubifs.h" 26 27 /** 28 * ubifs_compare_master_node - compare two UBIFS master nodes 29 * @c: UBIFS file-system description object 30 * @m1: the first node 31 * @m2: the second node 32 * 33 * This function compares two UBIFS master nodes. Returns 0 if they are equal 34 * and nonzero if not. 35 */ 36 int ubifs_compare_master_node(struct ubifs_info *c, void *m1, void *m2) 37 { 38 int ret; 39 int behind; 40 int hmac_offs = offsetof(struct ubifs_mst_node, hmac); 41 42 /* 43 * Do not compare the common node header since the sequence number and 44 * hence the CRC are different. 45 */ 46 ret = memcmp(m1 + UBIFS_CH_SZ, m2 + UBIFS_CH_SZ, 47 hmac_offs - UBIFS_CH_SZ); 48 if (ret) 49 return ret; 50 51 /* 52 * Do not compare the embedded HMAC aswell which also must be different 53 * due to the different common node header. 54 */ 55 behind = hmac_offs + UBIFS_MAX_HMAC_LEN; 56 57 if (UBIFS_MST_NODE_SZ > behind) 58 return memcmp(m1 + behind, m2 + behind, UBIFS_MST_NODE_SZ - behind); 59 60 return 0; 61 } 62 63 /** 64 * scan_for_master - search the valid master node. 65 * @c: UBIFS file-system description object 66 * 67 * This function scans the master node LEBs and search for the latest master 68 * node. Returns zero in case of success, %-EUCLEAN if there master area is 69 * corrupted and requires recovery, and a negative error code in case of 70 * failure. 71 */ 72 static int scan_for_master(struct ubifs_info *c) 73 { 74 struct ubifs_scan_leb *sleb; 75 struct ubifs_scan_node *snod; 76 int lnum, offs = 0, nodes_cnt, err; 77 78 lnum = UBIFS_MST_LNUM; 79 80 sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1); 81 if (IS_ERR(sleb)) 82 return PTR_ERR(sleb); 83 nodes_cnt = sleb->nodes_cnt; 84 if (nodes_cnt > 0) { 85 snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node, 86 list); 87 if (snod->type != UBIFS_MST_NODE) 88 goto out_dump; 89 memcpy(c->mst_node, snod->node, snod->len); 90 offs = snod->offs; 91 } 92 ubifs_scan_destroy(sleb); 93 94 lnum += 1; 95 96 sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1); 97 if (IS_ERR(sleb)) 98 return PTR_ERR(sleb); 99 if (sleb->nodes_cnt != nodes_cnt) 100 goto out; 101 if (!sleb->nodes_cnt) 102 goto out; 103 snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node, list); 104 if (snod->type != UBIFS_MST_NODE) 105 goto out_dump; 106 if (snod->offs != offs) 107 goto out; 108 if (ubifs_compare_master_node(c, c->mst_node, snod->node)) 109 goto out; 110 111 c->mst_offs = offs; 112 ubifs_scan_destroy(sleb); 113 114 if (!ubifs_authenticated(c)) 115 return 0; 116 117 err = ubifs_node_verify_hmac(c, c->mst_node, 118 sizeof(struct ubifs_mst_node), 119 offsetof(struct ubifs_mst_node, hmac)); 120 if (err) { 121 ubifs_err(c, "Failed to verify master node HMAC"); 122 return -EPERM; 123 } 124 125 return 0; 126 127 out: 128 ubifs_scan_destroy(sleb); 129 return -EUCLEAN; 130 131 out_dump: 132 ubifs_err(c, "unexpected node type %d master LEB %d:%d", 133 snod->type, lnum, snod->offs); 134 ubifs_scan_destroy(sleb); 135 return -EINVAL; 136 } 137 138 /** 139 * validate_master - validate master node. 140 * @c: UBIFS file-system description object 141 * 142 * This function validates data which was read from master node. Returns zero 143 * if the data is all right and %-EINVAL if not. 144 */ 145 static int validate_master(const struct ubifs_info *c) 146 { 147 long long main_sz; 148 int err; 149 150 if (c->max_sqnum >= SQNUM_WATERMARK) { 151 err = 1; 152 goto out; 153 } 154 155 if (c->cmt_no >= c->max_sqnum) { 156 err = 2; 157 goto out; 158 } 159 160 if (c->highest_inum >= INUM_WATERMARK) { 161 err = 3; 162 goto out; 163 } 164 165 if (c->lhead_lnum < UBIFS_LOG_LNUM || 166 c->lhead_lnum >= UBIFS_LOG_LNUM + c->log_lebs || 167 c->lhead_offs < 0 || c->lhead_offs >= c->leb_size || 168 c->lhead_offs & (c->min_io_size - 1)) { 169 err = 4; 170 goto out; 171 } 172 173 if (c->zroot.lnum >= c->leb_cnt || c->zroot.lnum < c->main_first || 174 c->zroot.offs >= c->leb_size || c->zroot.offs & 7) { 175 err = 5; 176 goto out; 177 } 178 179 if (c->zroot.len < c->ranges[UBIFS_IDX_NODE].min_len || 180 c->zroot.len > c->ranges[UBIFS_IDX_NODE].max_len) { 181 err = 6; 182 goto out; 183 } 184 185 if (c->gc_lnum >= c->leb_cnt || c->gc_lnum < c->main_first) { 186 err = 7; 187 goto out; 188 } 189 190 if (c->ihead_lnum >= c->leb_cnt || c->ihead_lnum < c->main_first || 191 c->ihead_offs % c->min_io_size || c->ihead_offs < 0 || 192 c->ihead_offs > c->leb_size || c->ihead_offs & 7) { 193 err = 8; 194 goto out; 195 } 196 197 main_sz = (long long)c->main_lebs * c->leb_size; 198 if (c->bi.old_idx_sz & 7 || c->bi.old_idx_sz >= main_sz) { 199 err = 9; 200 goto out; 201 } 202 203 if (c->lpt_lnum < c->lpt_first || c->lpt_lnum > c->lpt_last || 204 c->lpt_offs < 0 || c->lpt_offs + c->nnode_sz > c->leb_size) { 205 err = 10; 206 goto out; 207 } 208 209 if (c->nhead_lnum < c->lpt_first || c->nhead_lnum > c->lpt_last || 210 c->nhead_offs < 0 || c->nhead_offs % c->min_io_size || 211 c->nhead_offs > c->leb_size) { 212 err = 11; 213 goto out; 214 } 215 216 if (c->ltab_lnum < c->lpt_first || c->ltab_lnum > c->lpt_last || 217 c->ltab_offs < 0 || 218 c->ltab_offs + c->ltab_sz > c->leb_size) { 219 err = 12; 220 goto out; 221 } 222 223 if (c->big_lpt && (c->lsave_lnum < c->lpt_first || 224 c->lsave_lnum > c->lpt_last || c->lsave_offs < 0 || 225 c->lsave_offs + c->lsave_sz > c->leb_size)) { 226 err = 13; 227 goto out; 228 } 229 230 if (c->lscan_lnum < c->main_first || c->lscan_lnum >= c->leb_cnt) { 231 err = 14; 232 goto out; 233 } 234 235 if (c->lst.empty_lebs < 0 || c->lst.empty_lebs > c->main_lebs - 2) { 236 err = 15; 237 goto out; 238 } 239 240 if (c->lst.idx_lebs < 0 || c->lst.idx_lebs > c->main_lebs - 1) { 241 err = 16; 242 goto out; 243 } 244 245 if (c->lst.total_free < 0 || c->lst.total_free > main_sz || 246 c->lst.total_free & 7) { 247 err = 17; 248 goto out; 249 } 250 251 if (c->lst.total_dirty < 0 || (c->lst.total_dirty & 7)) { 252 err = 18; 253 goto out; 254 } 255 256 if (c->lst.total_used < 0 || (c->lst.total_used & 7)) { 257 err = 19; 258 goto out; 259 } 260 261 if (c->lst.total_free + c->lst.total_dirty + 262 c->lst.total_used > main_sz) { 263 err = 20; 264 goto out; 265 } 266 267 if (c->lst.total_dead + c->lst.total_dark + 268 c->lst.total_used + c->bi.old_idx_sz > main_sz) { 269 err = 21; 270 goto out; 271 } 272 273 if (c->lst.total_dead < 0 || 274 c->lst.total_dead > c->lst.total_free + c->lst.total_dirty || 275 c->lst.total_dead & 7) { 276 err = 22; 277 goto out; 278 } 279 280 if (c->lst.total_dark < 0 || 281 c->lst.total_dark > c->lst.total_free + c->lst.total_dirty || 282 c->lst.total_dark & 7) { 283 err = 23; 284 goto out; 285 } 286 287 return 0; 288 289 out: 290 ubifs_err(c, "bad master node at offset %d error %d", c->mst_offs, err); 291 ubifs_dump_node(c, c->mst_node); 292 return -EINVAL; 293 } 294 295 /** 296 * ubifs_read_master - read master node. 297 * @c: UBIFS file-system description object 298 * 299 * This function finds and reads the master node during file-system mount. If 300 * the flash is empty, it creates default master node as well. Returns zero in 301 * case of success and a negative error code in case of failure. 302 */ 303 int ubifs_read_master(struct ubifs_info *c) 304 { 305 int err, old_leb_cnt; 306 307 c->mst_node = kzalloc(c->mst_node_alsz, GFP_KERNEL); 308 if (!c->mst_node) 309 return -ENOMEM; 310 311 err = scan_for_master(c); 312 if (err) { 313 if (err == -EUCLEAN) 314 err = ubifs_recover_master_node(c); 315 if (err) 316 /* 317 * Note, we do not free 'c->mst_node' here because the 318 * unmount routine will take care of this. 319 */ 320 return err; 321 } 322 323 /* Make sure that the recovery flag is clear */ 324 c->mst_node->flags &= cpu_to_le32(~UBIFS_MST_RCVRY); 325 326 c->max_sqnum = le64_to_cpu(c->mst_node->ch.sqnum); 327 c->highest_inum = le64_to_cpu(c->mst_node->highest_inum); 328 c->cmt_no = le64_to_cpu(c->mst_node->cmt_no); 329 c->zroot.lnum = le32_to_cpu(c->mst_node->root_lnum); 330 c->zroot.offs = le32_to_cpu(c->mst_node->root_offs); 331 c->zroot.len = le32_to_cpu(c->mst_node->root_len); 332 c->lhead_lnum = le32_to_cpu(c->mst_node->log_lnum); 333 c->gc_lnum = le32_to_cpu(c->mst_node->gc_lnum); 334 c->ihead_lnum = le32_to_cpu(c->mst_node->ihead_lnum); 335 c->ihead_offs = le32_to_cpu(c->mst_node->ihead_offs); 336 c->bi.old_idx_sz = le64_to_cpu(c->mst_node->index_size); 337 c->lpt_lnum = le32_to_cpu(c->mst_node->lpt_lnum); 338 c->lpt_offs = le32_to_cpu(c->mst_node->lpt_offs); 339 c->nhead_lnum = le32_to_cpu(c->mst_node->nhead_lnum); 340 c->nhead_offs = le32_to_cpu(c->mst_node->nhead_offs); 341 c->ltab_lnum = le32_to_cpu(c->mst_node->ltab_lnum); 342 c->ltab_offs = le32_to_cpu(c->mst_node->ltab_offs); 343 c->lsave_lnum = le32_to_cpu(c->mst_node->lsave_lnum); 344 c->lsave_offs = le32_to_cpu(c->mst_node->lsave_offs); 345 c->lscan_lnum = le32_to_cpu(c->mst_node->lscan_lnum); 346 c->lst.empty_lebs = le32_to_cpu(c->mst_node->empty_lebs); 347 c->lst.idx_lebs = le32_to_cpu(c->mst_node->idx_lebs); 348 old_leb_cnt = le32_to_cpu(c->mst_node->leb_cnt); 349 c->lst.total_free = le64_to_cpu(c->mst_node->total_free); 350 c->lst.total_dirty = le64_to_cpu(c->mst_node->total_dirty); 351 c->lst.total_used = le64_to_cpu(c->mst_node->total_used); 352 c->lst.total_dead = le64_to_cpu(c->mst_node->total_dead); 353 c->lst.total_dark = le64_to_cpu(c->mst_node->total_dark); 354 355 ubifs_copy_hash(c, c->mst_node->hash_root_idx, c->zroot.hash); 356 357 c->calc_idx_sz = c->bi.old_idx_sz; 358 359 if (c->mst_node->flags & cpu_to_le32(UBIFS_MST_NO_ORPHS)) 360 c->no_orphs = 1; 361 362 if (old_leb_cnt != c->leb_cnt) { 363 /* The file system has been resized */ 364 int growth = c->leb_cnt - old_leb_cnt; 365 366 if (c->leb_cnt < old_leb_cnt || 367 c->leb_cnt < UBIFS_MIN_LEB_CNT) { 368 ubifs_err(c, "bad leb_cnt on master node"); 369 ubifs_dump_node(c, c->mst_node); 370 return -EINVAL; 371 } 372 373 dbg_mnt("Auto resizing (master) from %d LEBs to %d LEBs", 374 old_leb_cnt, c->leb_cnt); 375 c->lst.empty_lebs += growth; 376 c->lst.total_free += growth * (long long)c->leb_size; 377 c->lst.total_dark += growth * (long long)c->dark_wm; 378 379 /* 380 * Reflect changes back onto the master node. N.B. the master 381 * node gets written immediately whenever mounting (or 382 * remounting) in read-write mode, so we do not need to write it 383 * here. 384 */ 385 c->mst_node->leb_cnt = cpu_to_le32(c->leb_cnt); 386 c->mst_node->empty_lebs = cpu_to_le32(c->lst.empty_lebs); 387 c->mst_node->total_free = cpu_to_le64(c->lst.total_free); 388 c->mst_node->total_dark = cpu_to_le64(c->lst.total_dark); 389 } 390 391 err = validate_master(c); 392 if (err) 393 return err; 394 395 err = dbg_old_index_check_init(c, &c->zroot); 396 397 return err; 398 } 399 400 /** 401 * ubifs_write_master - write master node. 402 * @c: UBIFS file-system description object 403 * 404 * This function writes the master node. Returns zero in case of success and a 405 * negative error code in case of failure. The master node is written twice to 406 * enable recovery. 407 */ 408 int ubifs_write_master(struct ubifs_info *c) 409 { 410 int err, lnum, offs, len; 411 412 ubifs_assert(c, !c->ro_media && !c->ro_mount); 413 if (c->ro_error) 414 return -EROFS; 415 416 lnum = UBIFS_MST_LNUM; 417 offs = c->mst_offs + c->mst_node_alsz; 418 len = UBIFS_MST_NODE_SZ; 419 420 if (offs + UBIFS_MST_NODE_SZ > c->leb_size) { 421 err = ubifs_leb_unmap(c, lnum); 422 if (err) 423 return err; 424 offs = 0; 425 } 426 427 c->mst_offs = offs; 428 c->mst_node->highest_inum = cpu_to_le64(c->highest_inum); 429 430 ubifs_copy_hash(c, c->zroot.hash, c->mst_node->hash_root_idx); 431 err = ubifs_write_node_hmac(c, c->mst_node, len, lnum, offs, 432 offsetof(struct ubifs_mst_node, hmac)); 433 if (err) 434 return err; 435 436 lnum += 1; 437 438 if (offs == 0) { 439 err = ubifs_leb_unmap(c, lnum); 440 if (err) 441 return err; 442 } 443 err = ubifs_write_node_hmac(c, c->mst_node, len, lnum, offs, 444 offsetof(struct ubifs_mst_node, hmac)); 445 446 return err; 447 } 448