fs/ubifs/sb.c

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
get_default_compressor
create_default_filesystem
validate_sb
ubifs_read_sb_node
authenticate_sb_node
ubifs_write_sb_node
ubifs_read_superblock
fixup_leb
fixup_free_space
ubifs_fixup_free_space
ubifs_enable_encryption
   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         __le32 tmp_le32;
  88         struct timespec64 ts;
  89         u8 hash[UBIFS_HASH_ARR_SZ];
  90         u8 hash_lpt[UBIFS_HASH_ARR_SZ];
  91 
  92         /* Some functions called from here depend on the @c->key_len filed */
  93         c->key_len = UBIFS_SK_LEN;
  94 
  95         /*
  96          * First of all, we have to calculate default file-system geometry -
  97          * log size, journal size, etc.
  98          */
  99         if (c->leb_cnt < 0x7FFFFFFF / DEFAULT_JNL_PERCENT)
 100                 /* We can first multiply then divide and have no overflow */
 101                 jnl_lebs = c->leb_cnt * DEFAULT_JNL_PERCENT / 100;
 102         else
 103                 jnl_lebs = (c->leb_cnt / 100) * DEFAULT_JNL_PERCENT;
 104 
 105         if (jnl_lebs < UBIFS_MIN_JNL_LEBS)
 106                 jnl_lebs = UBIFS_MIN_JNL_LEBS;
 107         if (jnl_lebs * c->leb_size > DEFAULT_MAX_JNL)
 108                 jnl_lebs = DEFAULT_MAX_JNL / c->leb_size;
 109 
 110         /*
 111          * The log should be large enough to fit reference nodes for all bud
 112          * LEBs. Because buds do not have to start from the beginning of LEBs
 113          * (half of the LEB may contain committed data), the log should
 114          * generally be larger, make it twice as large.
 115          */
 116         tmp = 2 * (c->ref_node_alsz * jnl_lebs) + c->leb_size - 1;
 117         log_lebs = tmp / c->leb_size;
 118         /* Plus one LEB reserved for commit */
 119         log_lebs += 1;
 120         if (c->leb_cnt - min_leb_cnt > 8) {
 121                 /* And some extra space to allow writes while committing */
 122                 log_lebs += 1;
 123                 min_leb_cnt += 1;
 124         }
 125 
 126         max_buds = jnl_lebs - log_lebs;
 127         if (max_buds < UBIFS_MIN_BUD_LEBS)
 128                 max_buds = UBIFS_MIN_BUD_LEBS;
 129 
 130         /*
 131          * Orphan nodes are stored in a separate area. One node can store a lot
 132          * of orphan inode numbers, but when new orphan comes we just add a new
 133          * orphan node. At some point the nodes are consolidated into one
 134          * orphan node.
 135          */
 136         orph_lebs = UBIFS_MIN_ORPH_LEBS;
 137         if (c->leb_cnt - min_leb_cnt > 1)
 138                 /*
 139                  * For debugging purposes it is better to have at least 2
 140                  * orphan LEBs, because the orphan subsystem would need to do
 141                  * consolidations and would be stressed more.
 142                  */
 143                 orph_lebs += 1;
 144 
 145         main_lebs = c->leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS - log_lebs;
 146         main_lebs -= orph_lebs;
 147 
 148         lpt_first = UBIFS_LOG_LNUM + log_lebs;
 149         c->lsave_cnt = DEFAULT_LSAVE_CNT;
 150         c->max_leb_cnt = c->leb_cnt;
 151         err = ubifs_create_dflt_lpt(c, &main_lebs, lpt_first, &lpt_lebs,
 152                                     &big_lpt, hash_lpt);
 153         if (err)
 154                 return err;
 155 
 156         dbg_gen("LEB Properties Tree created (LEBs %d-%d)", lpt_first,
 157                 lpt_first + lpt_lebs - 1);
 158 
 159         main_first = c->leb_cnt - main_lebs;
 160 
 161         sup = kzalloc(ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size), GFP_KERNEL);
 162         mst = kzalloc(c->mst_node_alsz, GFP_KERNEL);
 163         idx_node_size = ubifs_idx_node_sz(c, 1);
 164         idx = kzalloc(ALIGN(idx_node_size, c->min_io_size), GFP_KERNEL);
 165         ino = kzalloc(ALIGN(UBIFS_INO_NODE_SZ, c->min_io_size), GFP_KERNEL);
 166         cs = kzalloc(ALIGN(UBIFS_CS_NODE_SZ, c->min_io_size), GFP_KERNEL);
 167 
 168         if (!sup || !mst || !idx || !ino || !cs) {
 169                 err = -ENOMEM;
 170                 goto out;
 171         }
 172 
 173         /* Create default superblock */
 174 
 175         tmp64 = (long long)max_buds * c->leb_size;
 176         if (big_lpt)
 177                 sup_flags |= UBIFS_FLG_BIGLPT;
 178         sup_flags |= UBIFS_FLG_DOUBLE_HASH;
 179 
 180         if (ubifs_authenticated(c)) {
 181                 sup_flags |= UBIFS_FLG_AUTHENTICATION;
 182                 sup->hash_algo = cpu_to_le16(c->auth_hash_algo);
 183                 err = ubifs_hmac_wkm(c, sup->hmac_wkm);
 184                 if (err)
 185                         goto out;
 186         } else {
 187                 sup->hash_algo = 0xffff;
 188         }
 189 
 190         sup->ch.node_type  = UBIFS_SB_NODE;
 191         sup->key_hash      = UBIFS_KEY_HASH_R5;
 192         sup->flags         = cpu_to_le32(sup_flags);
 193         sup->min_io_size   = cpu_to_le32(c->min_io_size);
 194         sup->leb_size      = cpu_to_le32(c->leb_size);
 195         sup->leb_cnt       = cpu_to_le32(c->leb_cnt);
 196         sup->max_leb_cnt   = cpu_to_le32(c->max_leb_cnt);
 197         sup->max_bud_bytes = cpu_to_le64(tmp64);
 198         sup->log_lebs      = cpu_to_le32(log_lebs);
 199         sup->lpt_lebs      = cpu_to_le32(lpt_lebs);
 200         sup->orph_lebs     = cpu_to_le32(orph_lebs);
 201         sup->jhead_cnt     = cpu_to_le32(DEFAULT_JHEADS_CNT);
 202         sup->fanout        = cpu_to_le32(DEFAULT_FANOUT);
 203         sup->lsave_cnt     = cpu_to_le32(c->lsave_cnt);
 204         sup->fmt_version   = cpu_to_le32(UBIFS_FORMAT_VERSION);
 205         sup->time_gran     = cpu_to_le32(DEFAULT_TIME_GRAN);
 206         if (c->mount_opts.override_compr)
 207                 sup->default_compr = cpu_to_le16(c->mount_opts.compr_type);
 208         else
 209                 sup->default_compr = cpu_to_le16(get_default_compressor(c));
 210 
 211         generate_random_uuid(sup->uuid);
 212 
 213         main_bytes = (long long)main_lebs * c->leb_size;
 214         tmp64 = div_u64(main_bytes * DEFAULT_RP_PERCENT, 100);
 215         if (tmp64 > DEFAULT_MAX_RP_SIZE)
 216                 tmp64 = DEFAULT_MAX_RP_SIZE;
 217         sup->rp_size = cpu_to_le64(tmp64);
 218         sup->ro_compat_version = cpu_to_le32(UBIFS_RO_COMPAT_VERSION);
 219 
 220         dbg_gen("default superblock created at LEB 0:0");
 221 
 222         /* Create default master node */
 223 
 224         mst->ch.node_type = UBIFS_MST_NODE;
 225         mst->log_lnum     = cpu_to_le32(UBIFS_LOG_LNUM);
 226         mst->highest_inum = cpu_to_le64(UBIFS_FIRST_INO);
 227         mst->cmt_no       = 0;
 228         mst->root_lnum    = cpu_to_le32(main_first + DEFAULT_IDX_LEB);
 229         mst->root_offs    = 0;
 230         tmp = ubifs_idx_node_sz(c, 1);
 231         mst->root_len     = cpu_to_le32(tmp);
 232         mst->gc_lnum      = cpu_to_le32(main_first + DEFAULT_GC_LEB);
 233         mst->ihead_lnum   = cpu_to_le32(main_first + DEFAULT_IDX_LEB);
 234         mst->ihead_offs   = cpu_to_le32(ALIGN(tmp, c->min_io_size));
 235         mst->index_size   = cpu_to_le64(ALIGN(tmp, 8));
 236         mst->lpt_lnum     = cpu_to_le32(c->lpt_lnum);
 237         mst->lpt_offs     = cpu_to_le32(c->lpt_offs);
 238         mst->nhead_lnum   = cpu_to_le32(c->nhead_lnum);
 239         mst->nhead_offs   = cpu_to_le32(c->nhead_offs);
 240         mst->ltab_lnum    = cpu_to_le32(c->ltab_lnum);
 241         mst->ltab_offs    = cpu_to_le32(c->ltab_offs);
 242         mst->lsave_lnum   = cpu_to_le32(c->lsave_lnum);
 243         mst->lsave_offs   = cpu_to_le32(c->lsave_offs);
 244         mst->lscan_lnum   = cpu_to_le32(main_first);
 245         mst->empty_lebs   = cpu_to_le32(main_lebs - 2);
 246         mst->idx_lebs     = cpu_to_le32(1);
 247         mst->leb_cnt      = cpu_to_le32(c->leb_cnt);
 248         ubifs_copy_hash(c, hash_lpt, mst->hash_lpt);
 249 
 250         /* Calculate lprops statistics */
 251         tmp64 = main_bytes;
 252         tmp64 -= ALIGN(ubifs_idx_node_sz(c, 1), c->min_io_size);
 253         tmp64 -= ALIGN(UBIFS_INO_NODE_SZ, c->min_io_size);
 254         mst->total_free = cpu_to_le64(tmp64);
 255 
 256         tmp64 = ALIGN(ubifs_idx_node_sz(c, 1), c->min_io_size);
 257         ino_waste = ALIGN(UBIFS_INO_NODE_SZ, c->min_io_size) -
 258                           UBIFS_INO_NODE_SZ;
 259         tmp64 += ino_waste;
 260         tmp64 -= ALIGN(ubifs_idx_node_sz(c, 1), 8);
 261         mst->total_dirty = cpu_to_le64(tmp64);
 262 
 263         /*  The indexing LEB does not contribute to dark space */
 264         tmp64 = ((long long)(c->main_lebs - 1) * c->dark_wm);
 265         mst->total_dark = cpu_to_le64(tmp64);
 266 
 267         mst->total_used = cpu_to_le64(UBIFS_INO_NODE_SZ);
 268 
 269         dbg_gen("default master node created at LEB %d:0", UBIFS_MST_LNUM);
 270 
 271         /* Create the root indexing node */
 272 
 273         c->key_fmt = UBIFS_SIMPLE_KEY_FMT;
 274         c->key_hash = key_r5_hash;
 275 
 276         idx->ch.node_type = UBIFS_IDX_NODE;
 277         idx->child_cnt = cpu_to_le16(1);
 278         ino_key_init(c, &key, UBIFS_ROOT_INO);
 279         br = ubifs_idx_branch(c, idx, 0);
 280         key_write_idx(c, &key, &br->key);
 281         br->lnum = cpu_to_le32(main_first + DEFAULT_DATA_LEB);
 282         br->len  = cpu_to_le32(UBIFS_INO_NODE_SZ);
 283 
 284         dbg_gen("default root indexing node created LEB %d:0",
 285                 main_first + DEFAULT_IDX_LEB);
 286 
 287         /* Create default root inode */
 288 
 289         ino_key_init_flash(c, &ino->key, UBIFS_ROOT_INO);
 290         ino->ch.node_type = UBIFS_INO_NODE;
 291         ino->creat_sqnum = cpu_to_le64(++c->max_sqnum);
 292         ino->nlink = cpu_to_le32(2);
 293 
 294         ktime_get_real_ts64(&ts);
 295         ts = timespec64_trunc(ts, DEFAULT_TIME_GRAN);
 296         tmp_le64 = cpu_to_le64(ts.tv_sec);
 297         ino->atime_sec   = tmp_le64;
 298         ino->ctime_sec   = tmp_le64;
 299         ino->mtime_sec   = tmp_le64;
 300         tmp_le32 = cpu_to_le32(ts.tv_nsec);
 301         ino->atime_nsec  = tmp_le32;
 302         ino->ctime_nsec  = tmp_le32;
 303         ino->mtime_nsec  = tmp_le32;
 304         ino->mode = cpu_to_le32(S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO);
 305         ino->size = cpu_to_le64(UBIFS_INO_NODE_SZ);
 306 
 307         /* Set compression enabled by default */
 308         ino->flags = cpu_to_le32(UBIFS_COMPR_FL);
 309 
 310         dbg_gen("root inode created at LEB %d:0",
 311                 main_first + DEFAULT_DATA_LEB);
 312 
 313         /*
 314          * The first node in the log has to be the commit start node. This is
 315          * always the case during normal file-system operation. Write a fake
 316          * commit start node to the log.
 317          */
 318 
 319         cs->ch.node_type = UBIFS_CS_NODE;
 320 
 321         err = ubifs_write_node_hmac(c, sup, UBIFS_SB_NODE_SZ, 0, 0,
 322                                     offsetof(struct ubifs_sb_node, hmac));
 323         if (err)
 324                 goto out;
 325 
 326         err = ubifs_write_node(c, ino, UBIFS_INO_NODE_SZ,
 327                                main_first + DEFAULT_DATA_LEB, 0);
 328         if (err)
 329                 goto out;
 330 
 331         ubifs_node_calc_hash(c, ino, hash);
 332         ubifs_copy_hash(c, hash, ubifs_branch_hash(c, br));
 333 
 334         err = ubifs_write_node(c, idx, idx_node_size, main_first + DEFAULT_IDX_LEB, 0);
 335         if (err)
 336                 goto out;
 337 
 338         ubifs_node_calc_hash(c, idx, hash);
 339         ubifs_copy_hash(c, hash, mst->hash_root_idx);
 340 
 341         err = ubifs_write_node_hmac(c, mst, UBIFS_MST_NODE_SZ, UBIFS_MST_LNUM, 0,
 342                 offsetof(struct ubifs_mst_node, hmac));
 343         if (err)
 344                 goto out;
 345 
 346         err = ubifs_write_node_hmac(c, mst, UBIFS_MST_NODE_SZ, UBIFS_MST_LNUM + 1,
 347                                0, offsetof(struct ubifs_mst_node, hmac));
 348         if (err)
 349                 goto out;
 350 
 351         err = ubifs_write_node(c, cs, UBIFS_CS_NODE_SZ, UBIFS_LOG_LNUM, 0);
 352         if (err)
 353                 goto out;
 354 
 355         ubifs_msg(c, "default file-system created");
 356 
 357         err = 0;
 358 out:
 359         kfree(sup);
 360         kfree(mst);
 361         kfree(idx);
 362         kfree(ino);
 363         kfree(cs);
 364 
 365         return err;
 366 }
 367 
 368 /**
 369  * validate_sb - validate superblock node.
 370  * @c: UBIFS file-system description object
 371  * @sup: superblock node
 372  *
 373  * This function validates superblock node @sup. Since most of data was read
 374  * from the superblock and stored in @c, the function validates fields in @c
 375  * instead. Returns zero in case of success and %-EINVAL in case of validation
 376  * failure.
 377  */
 378 static int validate_sb(struct ubifs_info *c, struct ubifs_sb_node *sup)
 379 {
 380         long long max_bytes;
 381         int err = 1, min_leb_cnt;
 382 
 383         if (!c->key_hash) {
 384                 err = 2;
 385                 goto failed;
 386         }
 387 
 388         if (sup->key_fmt != UBIFS_SIMPLE_KEY_FMT) {
 389                 err = 3;
 390                 goto failed;
 391         }
 392 
 393         if (le32_to_cpu(sup->min_io_size) != c->min_io_size) {
 394                 ubifs_err(c, "min. I/O unit mismatch: %d in superblock, %d real",
 395                           le32_to_cpu(sup->min_io_size), c->min_io_size);
 396                 goto failed;
 397         }
 398 
 399         if (le32_to_cpu(sup->leb_size) != c->leb_size) {
 400                 ubifs_err(c, "LEB size mismatch: %d in superblock, %d real",
 401                           le32_to_cpu(sup->leb_size), c->leb_size);
 402                 goto failed;
 403         }
 404 
 405         if (c->log_lebs < UBIFS_MIN_LOG_LEBS ||
 406             c->lpt_lebs < UBIFS_MIN_LPT_LEBS ||
 407             c->orph_lebs < UBIFS_MIN_ORPH_LEBS ||
 408             c->main_lebs < UBIFS_MIN_MAIN_LEBS) {
 409                 err = 4;
 410                 goto failed;
 411         }
 412 
 413         /*
 414          * Calculate minimum allowed amount of main area LEBs. This is very
 415          * similar to %UBIFS_MIN_LEB_CNT, but we take into account real what we
 416          * have just read from the superblock.
 417          */
 418         min_leb_cnt = UBIFS_SB_LEBS + UBIFS_MST_LEBS + c->log_lebs;
 419         min_leb_cnt += c->lpt_lebs + c->orph_lebs + c->jhead_cnt + 6;
 420 
 421         if (c->leb_cnt < min_leb_cnt || c->leb_cnt > c->vi.size) {
 422                 ubifs_err(c, "bad LEB count: %d in superblock, %d on UBI volume, %d minimum required",
 423                           c->leb_cnt, c->vi.size, min_leb_cnt);
 424                 goto failed;
 425         }
 426 
 427         if (c->max_leb_cnt < c->leb_cnt) {
 428                 ubifs_err(c, "max. LEB count %d less than LEB count %d",
 429                           c->max_leb_cnt, c->leb_cnt);
 430                 goto failed;
 431         }
 432 
 433         if (c->main_lebs < UBIFS_MIN_MAIN_LEBS) {
 434                 ubifs_err(c, "too few main LEBs count %d, must be at least %d",
 435                           c->main_lebs, UBIFS_MIN_MAIN_LEBS);
 436                 goto failed;
 437         }
 438 
 439         max_bytes = (long long)c->leb_size * UBIFS_MIN_BUD_LEBS;
 440         if (c->max_bud_bytes < max_bytes) {
 441                 ubifs_err(c, "too small journal (%lld bytes), must be at least %lld bytes",
 442                           c->max_bud_bytes, max_bytes);
 443                 goto failed;
 444         }
 445 
 446         max_bytes = (long long)c->leb_size * c->main_lebs;
 447         if (c->max_bud_bytes > max_bytes) {
 448                 ubifs_err(c, "too large journal size (%lld bytes), only %lld bytes available in the main area",
 449                           c->max_bud_bytes, max_bytes);
 450                 goto failed;
 451         }
 452 
 453         if (c->jhead_cnt < NONDATA_JHEADS_CNT + 1 ||
 454             c->jhead_cnt > NONDATA_JHEADS_CNT + UBIFS_MAX_JHEADS) {
 455                 err = 9;
 456                 goto failed;
 457         }
 458 
 459         if (c->fanout < UBIFS_MIN_FANOUT ||
 460             ubifs_idx_node_sz(c, c->fanout) > c->leb_size) {
 461                 err = 10;
 462                 goto failed;
 463         }
 464 
 465         if (c->lsave_cnt < 0 || (c->lsave_cnt > DEFAULT_LSAVE_CNT &&
 466             c->lsave_cnt > c->max_leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS -
 467             c->log_lebs - c->lpt_lebs - c->orph_lebs)) {
 468                 err = 11;
 469                 goto failed;
 470         }
 471 
 472         if (UBIFS_SB_LEBS + UBIFS_MST_LEBS + c->log_lebs + c->lpt_lebs +
 473             c->orph_lebs + c->main_lebs != c->leb_cnt) {
 474                 err = 12;
 475                 goto failed;
 476         }
 477 
 478         if (c->default_compr >= UBIFS_COMPR_TYPES_CNT) {
 479                 err = 13;
 480                 goto failed;
 481         }
 482 
 483         if (c->rp_size < 0 || max_bytes < c->rp_size) {
 484                 err = 14;
 485                 goto failed;
 486         }
 487 
 488         if (le32_to_cpu(sup->time_gran) > 1000000000 ||
 489             le32_to_cpu(sup->time_gran) < 1) {
 490                 err = 15;
 491                 goto failed;
 492         }
 493 
 494         if (!c->double_hash && c->fmt_version >= 5) {
 495                 err = 16;
 496                 goto failed;
 497         }
 498 
 499         if (c->encrypted && c->fmt_version < 5) {
 500                 err = 17;
 501                 goto failed;
 502         }
 503 
 504         return 0;
 505 
 506 failed:
 507         ubifs_err(c, "bad superblock, error %d", err);
 508         ubifs_dump_node(c, sup);
 509         return -EINVAL;
 510 }
 511 
 512 /**
 513  * ubifs_read_sb_node - read superblock node.
 514  * @c: UBIFS file-system description object
 515  *
 516  * This function returns a pointer to the superblock node or a negative error
 517  * code. Note, the user of this function is responsible of kfree()'ing the
 518  * returned superblock buffer.
 519  */
 520 static struct ubifs_sb_node *ubifs_read_sb_node(struct ubifs_info *c)
 521 {
 522         struct ubifs_sb_node *sup;
 523         int err;
 524 
 525         sup = kmalloc(ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size), GFP_NOFS);
 526         if (!sup)
 527                 return ERR_PTR(-ENOMEM);
 528 
 529         err = ubifs_read_node(c, sup, UBIFS_SB_NODE, UBIFS_SB_NODE_SZ,
 530                               UBIFS_SB_LNUM, 0);
 531         if (err) {
 532                 kfree(sup);
 533                 return ERR_PTR(err);
 534         }
 535 
 536         return sup;
 537 }
 538 
 539 static int authenticate_sb_node(struct ubifs_info *c,
 540                                 const struct ubifs_sb_node *sup)
 541 {
 542         unsigned int sup_flags = le32_to_cpu(sup->flags);
 543         u8 hmac_wkm[UBIFS_HMAC_ARR_SZ];
 544         int authenticated = !!(sup_flags & UBIFS_FLG_AUTHENTICATION);
 545         int hash_algo;
 546         int err;
 547 
 548         if (c->authenticated && !authenticated) {
 549                 ubifs_err(c, "authenticated FS forced, but found FS without authentication");
 550                 return -EINVAL;
 551         }
 552 
 553         if (!c->authenticated && authenticated) {
 554                 ubifs_err(c, "authenticated FS found, but no key given");
 555                 return -EINVAL;
 556         }
 557 
 558         ubifs_msg(c, "Mounting in %sauthenticated mode",
 559                   c->authenticated ? "" : "un");
 560 
 561         if (!c->authenticated)
 562                 return 0;
 563 
 564         if (!IS_ENABLED(CONFIG_UBIFS_FS_AUTHENTICATION))
 565                 return -EOPNOTSUPP;
 566 
 567         hash_algo = le16_to_cpu(sup->hash_algo);
 568         if (hash_algo >= HASH_ALGO__LAST) {
 569                 ubifs_err(c, "superblock uses unknown hash algo %d",
 570                           hash_algo);
 571                 return -EINVAL;
 572         }
 573 
 574         if (strcmp(hash_algo_name[hash_algo], c->auth_hash_name)) {
 575                 ubifs_err(c, "This filesystem uses %s for hashing,"
 576                              " but %s is specified", hash_algo_name[hash_algo],
 577                              c->auth_hash_name);
 578                 return -EINVAL;
 579         }
 580 
 581         /*
 582          * The super block node can either be authenticated by a HMAC or
 583          * by a signature in a ubifs_sig_node directly following the
 584          * super block node to support offline image creation.
 585          */
 586         if (ubifs_hmac_zero(c, sup->hmac)) {
 587                 err = ubifs_sb_verify_signature(c, sup);
 588         } else {
 589                 err = ubifs_hmac_wkm(c, hmac_wkm);
 590                 if (err)
 591                         return err;
 592                 if (ubifs_check_hmac(c, hmac_wkm, sup->hmac_wkm)) {
 593                         ubifs_err(c, "provided key does not fit");
 594                         return -ENOKEY;
 595                 }
 596                 err = ubifs_node_verify_hmac(c, sup, sizeof(*sup),
 597                                              offsetof(struct ubifs_sb_node,
 598                                                       hmac));
 599         }
 600 
 601         if (err)
 602                 ubifs_err(c, "Failed to authenticate superblock: %d", err);
 603 
 604         return err;
 605 }
 606 
 607 /**
 608  * ubifs_write_sb_node - write superblock node.
 609  * @c: UBIFS file-system description object
 610  * @sup: superblock node read with 'ubifs_read_sb_node()'
 611  *
 612  * This function returns %0 on success and a negative error code on failure.
 613  */
 614 int ubifs_write_sb_node(struct ubifs_info *c, struct ubifs_sb_node *sup)
 615 {
 616         int len = ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size);
 617         int err;
 618 
 619         err = ubifs_prepare_node_hmac(c, sup, UBIFS_SB_NODE_SZ,
 620                                       offsetof(struct ubifs_sb_node, hmac), 1);
 621         if (err)
 622                 return err;
 623 
 624         return ubifs_leb_change(c, UBIFS_SB_LNUM, sup, len);
 625 }
 626 
 627 /**
 628  * ubifs_read_superblock - read superblock.
 629  * @c: UBIFS file-system description object
 630  *
 631  * This function finds, reads and checks the superblock. If an empty UBI volume
 632  * is being mounted, this function creates default superblock. Returns zero in
 633  * case of success, and a negative error code in case of failure.
 634  */
 635 int ubifs_read_superblock(struct ubifs_info *c)
 636 {
 637         int err, sup_flags;
 638         struct ubifs_sb_node *sup;
 639 
 640         if (c->empty) {
 641                 err = create_default_filesystem(c);
 642                 if (err)
 643                         return err;
 644         }
 645 
 646         sup = ubifs_read_sb_node(c);
 647         if (IS_ERR(sup))
 648                 return PTR_ERR(sup);
 649 
 650         c->sup_node = sup;
 651 
 652         c->fmt_version = le32_to_cpu(sup->fmt_version);
 653         c->ro_compat_version = le32_to_cpu(sup->ro_compat_version);
 654 
 655         /*
 656          * The software supports all previous versions but not future versions,
 657          * due to the unavailability of time-travelling equipment.
 658          */
 659         if (c->fmt_version > UBIFS_FORMAT_VERSION) {
 660                 ubifs_assert(c, !c->ro_media || c->ro_mount);
 661                 if (!c->ro_mount ||
 662                     c->ro_compat_version > UBIFS_RO_COMPAT_VERSION) {
 663                         ubifs_err(c, "on-flash format version is w%d/r%d, but software only supports up to version w%d/r%d",
 664                                   c->fmt_version, c->ro_compat_version,
 665                                   UBIFS_FORMAT_VERSION,
 666                                   UBIFS_RO_COMPAT_VERSION);
 667                         if (c->ro_compat_version <= UBIFS_RO_COMPAT_VERSION) {
 668                                 ubifs_msg(c, "only R/O mounting is possible");
 669                                 err = -EROFS;
 670                         } else
 671                                 err = -EINVAL;
 672                         goto out;
 673                 }
 674 
 675                 /*
 676                  * The FS is mounted R/O, and the media format is
 677                  * R/O-compatible with the UBIFS implementation, so we can
 678                  * mount.
 679                  */
 680                 c->rw_incompat = 1;
 681         }
 682 
 683         if (c->fmt_version < 3) {
 684                 ubifs_err(c, "on-flash format version %d is not supported",
 685                           c->fmt_version);
 686                 err = -EINVAL;
 687                 goto out;
 688         }
 689 
 690         switch (sup->key_hash) {
 691         case UBIFS_KEY_HASH_R5:
 692                 c->key_hash = key_r5_hash;
 693                 c->key_hash_type = UBIFS_KEY_HASH_R5;
 694                 break;
 695 
 696         case UBIFS_KEY_HASH_TEST:
 697                 c->key_hash = key_test_hash;
 698                 c->key_hash_type = UBIFS_KEY_HASH_TEST;
 699                 break;
 700         }
 701 
 702         c->key_fmt = sup->key_fmt;
 703 
 704         switch (c->key_fmt) {
 705         case UBIFS_SIMPLE_KEY_FMT:
 706                 c->key_len = UBIFS_SK_LEN;
 707                 break;
 708         default:
 709                 ubifs_err(c, "unsupported key format");
 710                 err = -EINVAL;
 711                 goto out;
 712         }
 713 
 714         c->leb_cnt       = le32_to_cpu(sup->leb_cnt);
 715         c->max_leb_cnt   = le32_to_cpu(sup->max_leb_cnt);
 716         c->max_bud_bytes = le64_to_cpu(sup->max_bud_bytes);
 717         c->log_lebs      = le32_to_cpu(sup->log_lebs);
 718         c->lpt_lebs      = le32_to_cpu(sup->lpt_lebs);
 719         c->orph_lebs     = le32_to_cpu(sup->orph_lebs);
 720         c->jhead_cnt     = le32_to_cpu(sup->jhead_cnt) + NONDATA_JHEADS_CNT;
 721         c->fanout        = le32_to_cpu(sup->fanout);
 722         c->lsave_cnt     = le32_to_cpu(sup->lsave_cnt);
 723         c->rp_size       = le64_to_cpu(sup->rp_size);
 724         c->rp_uid        = make_kuid(&init_user_ns, le32_to_cpu(sup->rp_uid));
 725         c->rp_gid        = make_kgid(&init_user_ns, le32_to_cpu(sup->rp_gid));
 726         sup_flags        = le32_to_cpu(sup->flags);
 727         if (!c->mount_opts.override_compr)
 728                 c->default_compr = le16_to_cpu(sup->default_compr);
 729 
 730         c->vfs_sb->s_time_gran = le32_to_cpu(sup->time_gran);
 731         memcpy(&c->uuid, &sup->uuid, 16);
 732         c->big_lpt = !!(sup_flags & UBIFS_FLG_BIGLPT);
 733         c->space_fixup = !!(sup_flags & UBIFS_FLG_SPACE_FIXUP);
 734         c->double_hash = !!(sup_flags & UBIFS_FLG_DOUBLE_HASH);
 735         c->encrypted = !!(sup_flags & UBIFS_FLG_ENCRYPTION);
 736 
 737         err = authenticate_sb_node(c, sup);
 738         if (err)
 739                 goto out;
 740 
 741         if ((sup_flags & ~UBIFS_FLG_MASK) != 0) {
 742                 ubifs_err(c, "Unknown feature flags found: %#x",
 743                           sup_flags & ~UBIFS_FLG_MASK);
 744                 err = -EINVAL;
 745                 goto out;
 746         }
 747 
 748         if (!IS_ENABLED(CONFIG_FS_ENCRYPTION) && c->encrypted) {
 749                 ubifs_err(c, "file system contains encrypted files but UBIFS"
 750                              " was built without crypto support.");
 751                 err = -EINVAL;
 752                 goto out;
 753         }
 754 
 755         /* Automatically increase file system size to the maximum size */
 756         if (c->leb_cnt < c->vi.size && c->leb_cnt < c->max_leb_cnt) {
 757                 int old_leb_cnt = c->leb_cnt;
 758 
 759                 c->leb_cnt = min_t(int, c->max_leb_cnt, c->vi.size);
 760                 sup->leb_cnt = cpu_to_le32(c->leb_cnt);
 761 
 762                 c->superblock_need_write = 1;
 763 
 764                 dbg_mnt("Auto resizing from %d LEBs to %d LEBs",
 765                         old_leb_cnt, c->leb_cnt);
 766         }
 767 
 768         c->log_bytes = (long long)c->log_lebs * c->leb_size;
 769         c->log_last = UBIFS_LOG_LNUM + c->log_lebs - 1;
 770         c->lpt_first = UBIFS_LOG_LNUM + c->log_lebs;
 771         c->lpt_last = c->lpt_first + c->lpt_lebs - 1;
 772         c->orph_first = c->lpt_last + 1;
 773         c->orph_last = c->orph_first + c->orph_lebs - 1;
 774         c->main_lebs = c->leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS;
 775         c->main_lebs -= c->log_lebs + c->lpt_lebs + c->orph_lebs;
 776         c->main_first = c->leb_cnt - c->main_lebs;
 777 
 778         err = validate_sb(c, sup);
 779 out:
 780         return err;
 781 }
 782 
 783 /**
 784  * fixup_leb - fixup/unmap an LEB containing free space.
 785  * @c: UBIFS file-system description object
 786  * @lnum: the LEB number to fix up
 787  * @len: number of used bytes in LEB (starting at offset 0)
 788  *
 789  * This function reads the contents of the given LEB number @lnum, then fixes
 790  * it up, so that empty min. I/O units in the end of LEB are actually erased on
 791  * flash (rather than being just all-0xff real data). If the LEB is completely
 792  * empty, it is simply unmapped.
 793  */
 794 static int fixup_leb(struct ubifs_info *c, int lnum, int len)
 795 {
 796         int err;
 797 
 798         ubifs_assert(c, len >= 0);
 799         ubifs_assert(c, len % c->min_io_size == 0);
 800         ubifs_assert(c, len < c->leb_size);
 801 
 802         if (len == 0) {
 803                 dbg_mnt("unmap empty LEB %d", lnum);
 804                 return ubifs_leb_unmap(c, lnum);
 805         }
 806 
 807         dbg_mnt("fixup LEB %d, data len %d", lnum, len);
 808         err = ubifs_leb_read(c, lnum, c->sbuf, 0, len, 1);
 809         if (err)
 810                 return err;
 811 
 812         return ubifs_leb_change(c, lnum, c->sbuf, len);
 813 }
 814 
 815 /**
 816  * fixup_free_space - find & remap all LEBs containing free space.
 817  * @c: UBIFS file-system description object
 818  *
 819  * This function walks through all LEBs in the filesystem and fiexes up those
 820  * containing free/empty space.
 821  */
 822 static int fixup_free_space(struct ubifs_info *c)
 823 {
 824         int lnum, err = 0;
 825         struct ubifs_lprops *lprops;
 826 
 827         ubifs_get_lprops(c);
 828 
 829         /* Fixup LEBs in the master area */
 830         for (lnum = UBIFS_MST_LNUM; lnum < UBIFS_LOG_LNUM; lnum++) {
 831                 err = fixup_leb(c, lnum, c->mst_offs + c->mst_node_alsz);
 832                 if (err)
 833                         goto out;
 834         }
 835 
 836         /* Unmap unused log LEBs */
 837         lnum = ubifs_next_log_lnum(c, c->lhead_lnum);
 838         while (lnum != c->ltail_lnum) {
 839                 err = fixup_leb(c, lnum, 0);
 840                 if (err)
 841                         goto out;
 842                 lnum = ubifs_next_log_lnum(c, lnum);
 843         }
 844 
 845         /*
 846          * Fixup the log head which contains the only a CS node at the
 847          * beginning.
 848          */
 849         err = fixup_leb(c, c->lhead_lnum,
 850                         ALIGN(UBIFS_CS_NODE_SZ, c->min_io_size));
 851         if (err)
 852                 goto out;
 853 
 854         /* Fixup LEBs in the LPT area */
 855         for (lnum = c->lpt_first; lnum <= c->lpt_last; lnum++) {
 856                 int free = c->ltab[lnum - c->lpt_first].free;
 857 
 858                 if (free > 0) {
 859                         err = fixup_leb(c, lnum, c->leb_size - free);
 860                         if (err)
 861                                 goto out;
 862                 }
 863         }
 864 
 865         /* Unmap LEBs in the orphans area */
 866         for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
 867                 err = fixup_leb(c, lnum, 0);
 868                 if (err)
 869                         goto out;
 870         }
 871 
 872         /* Fixup LEBs in the main area */
 873         for (lnum = c->main_first; lnum < c->leb_cnt; lnum++) {
 874                 lprops = ubifs_lpt_lookup(c, lnum);
 875                 if (IS_ERR(lprops)) {
 876                         err = PTR_ERR(lprops);
 877                         goto out;
 878                 }
 879 
 880                 if (lprops->free > 0) {
 881                         err = fixup_leb(c, lnum, c->leb_size - lprops->free);
 882                         if (err)
 883                                 goto out;
 884                 }
 885         }
 886 
 887 out:
 888         ubifs_release_lprops(c);
 889         return err;
 890 }
 891 
 892 /**
 893  * ubifs_fixup_free_space - find & fix all LEBs with free space.
 894  * @c: UBIFS file-system description object
 895  *
 896  * This function fixes up LEBs containing free space on first mount, if the
 897  * appropriate flag was set when the FS was created. Each LEB with one or more
 898  * empty min. I/O unit (i.e. free-space-count > 0) is re-written, to make sure
 899  * the free space is actually erased. E.g., this is necessary for some NAND
 900  * chips, since the free space may have been programmed like real "0xff" data
 901  * (generating a non-0xff ECC), causing future writes to the not-really-erased
 902  * NAND pages to behave badly. After the space is fixed up, the superblock flag
 903  * is cleared, so that this is skipped for all future mounts.
 904  */
 905 int ubifs_fixup_free_space(struct ubifs_info *c)
 906 {
 907         int err;
 908         struct ubifs_sb_node *sup = c->sup_node;
 909 
 910         ubifs_assert(c, c->space_fixup);
 911         ubifs_assert(c, !c->ro_mount);
 912 
 913         ubifs_msg(c, "start fixing up free space");
 914 
 915         err = fixup_free_space(c);
 916         if (err)
 917                 return err;
 918 
 919         /* Free-space fixup is no longer required */
 920         c->space_fixup = 0;
 921         sup->flags &= cpu_to_le32(~UBIFS_FLG_SPACE_FIXUP);
 922 
 923         c->superblock_need_write = 1;
 924 
 925         ubifs_msg(c, "free space fixup complete");
 926         return err;
 927 }
 928 
 929 int ubifs_enable_encryption(struct ubifs_info *c)
 930 {
 931         int err;
 932         struct ubifs_sb_node *sup = c->sup_node;
 933 
 934         if (!IS_ENABLED(CONFIG_FS_ENCRYPTION))
 935                 return -EOPNOTSUPP;
 936 
 937         if (c->encrypted)
 938                 return 0;
 939 
 940         if (c->ro_mount || c->ro_media)
 941                 return -EROFS;
 942 
 943         if (c->fmt_version < 5) {
 944                 ubifs_err(c, "on-flash format version 5 is needed for encryption");
 945                 return -EINVAL;
 946         }
 947 
 948         sup->flags |= cpu_to_le32(UBIFS_FLG_ENCRYPTION);
 949 
 950         err = ubifs_write_sb_node(c, sup);
 951         if (!err)
 952                 c->encrypted = 1;
 953 
 954         return err;
 955 }
/* [<][>][^][v][top][bottom][index][help] */
root/fs/ubifs/sb.c

DEFINITIONS
