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
get_default_compressor(struct ubifs_info * c)54 static int get_default_compressor(struct ubifs_info *c)
55 {
56 if (ubifs_compr_present(c, UBIFS_COMPR_ZSTD))
57 return UBIFS_COMPR_ZSTD;
58
59 if (ubifs_compr_present(c, UBIFS_COMPR_LZO))
60 return UBIFS_COMPR_LZO;
61
62 if (ubifs_compr_present(c, UBIFS_COMPR_ZLIB))
63 return UBIFS_COMPR_ZLIB;
64
65 return UBIFS_COMPR_NONE;
66 }
67
68 /**
69 * create_default_filesystem - format empty UBI volume.
70 * @c: UBIFS file-system description object
71 *
72 * This function creates default empty file-system. Returns zero in case of
73 * success and a negative error code in case of failure.
74 */
create_default_filesystem(struct ubifs_info * c)75 static int create_default_filesystem(struct ubifs_info *c)
76 {
77 struct ubifs_sb_node *sup;
78 struct ubifs_mst_node *mst;
79 struct ubifs_idx_node *idx;
80 struct ubifs_branch *br;
81 struct ubifs_ino_node *ino;
82 struct ubifs_cs_node *cs;
83 union ubifs_key key;
84 int err, tmp, jnl_lebs, log_lebs, max_buds, main_lebs, main_first;
85 int lpt_lebs, lpt_first, orph_lebs, big_lpt, ino_waste, sup_flags = 0;
86 int min_leb_cnt = UBIFS_MIN_LEB_CNT;
87 int idx_node_size;
88 long long tmp64, main_bytes;
89 __le64 tmp_le64;
90 struct timespec64 ts;
91 u8 hash[UBIFS_HASH_ARR_SZ];
92 u8 hash_lpt[UBIFS_HASH_ARR_SZ];
93
94 /* Some functions called from here depend on the @c->key_len filed */
95 c->key_len = UBIFS_SK_LEN;
96
97 /*
98 * First of all, we have to calculate default file-system geometry -
99 * log size, journal size, etc.
100 */
101 if (c->leb_cnt < 0x7FFFFFFF / DEFAULT_JNL_PERCENT)
102 /* We can first multiply then divide and have no overflow */
103 jnl_lebs = c->leb_cnt * DEFAULT_JNL_PERCENT / 100;
104 else
105 jnl_lebs = (c->leb_cnt / 100) * DEFAULT_JNL_PERCENT;
106
107 if (jnl_lebs < UBIFS_MIN_JNL_LEBS)
108 jnl_lebs = UBIFS_MIN_JNL_LEBS;
109 if (jnl_lebs * c->leb_size > DEFAULT_MAX_JNL)
110 jnl_lebs = DEFAULT_MAX_JNL / c->leb_size;
111
112 /*
113 * The log should be large enough to fit reference nodes for all bud
114 * LEBs. Because buds do not have to start from the beginning of LEBs
115 * (half of the LEB may contain committed data), the log should
116 * generally be larger, make it twice as large.
117 */
118 tmp = 2 * (c->ref_node_alsz * jnl_lebs) + c->leb_size - 1;
119 log_lebs = tmp / c->leb_size;
120 /* Plus one LEB reserved for commit */
121 log_lebs += 1;
122 if (c->leb_cnt - min_leb_cnt > 8) {
123 /* And some extra space to allow writes while committing */
124 log_lebs += 1;
125 min_leb_cnt += 1;
126 }
127
128 max_buds = jnl_lebs - log_lebs;
129 if (max_buds < UBIFS_MIN_BUD_LEBS)
130 max_buds = UBIFS_MIN_BUD_LEBS;
131
132 /*
133 * Orphan nodes are stored in a separate area. One node can store a lot
134 * of orphan inode numbers, but when new orphan comes we just add a new
135 * orphan node. At some point the nodes are consolidated into one
136 * orphan node.
137 */
138 orph_lebs = UBIFS_MIN_ORPH_LEBS;
139 if (c->leb_cnt - min_leb_cnt > 1)
140 /*
141 * For debugging purposes it is better to have at least 2
142 * orphan LEBs, because the orphan subsystem would need to do
143 * consolidations and would be stressed more.
144 */
145 orph_lebs += 1;
146
147 main_lebs = c->leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS - log_lebs;
148 main_lebs -= orph_lebs;
149
150 lpt_first = UBIFS_LOG_LNUM + log_lebs;
151 c->lsave_cnt = DEFAULT_LSAVE_CNT;
152 c->max_leb_cnt = c->leb_cnt;
153 err = ubifs_create_dflt_lpt(c, &main_lebs, lpt_first, &lpt_lebs,
154 &big_lpt, hash_lpt);
155 if (err)
156 return err;
157
158 dbg_gen("LEB Properties Tree created (LEBs %d-%d)", lpt_first,
159 lpt_first + lpt_lebs - 1);
160
161 main_first = c->leb_cnt - main_lebs;
162
163 sup = kzalloc(ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size), GFP_KERNEL);
164 mst = kzalloc(c->mst_node_alsz, GFP_KERNEL);
165 idx_node_size = ubifs_idx_node_sz(c, 1);
166 idx = kzalloc(ALIGN(idx_node_size, c->min_io_size), GFP_KERNEL);
167 ino = kzalloc(ALIGN(UBIFS_INO_NODE_SZ, c->min_io_size), GFP_KERNEL);
168 cs = kzalloc(ALIGN(UBIFS_CS_NODE_SZ, c->min_io_size), GFP_KERNEL);
169
170 if (!sup || !mst || !idx || !ino || !cs) {
171 err = -ENOMEM;
172 goto out;
173 }
174
175 /* Create default superblock */
176
177 tmp64 = (long long)max_buds * c->leb_size;
178 if (big_lpt)
179 sup_flags |= UBIFS_FLG_BIGLPT;
180 if (ubifs_default_version > 4)
181 sup_flags |= UBIFS_FLG_DOUBLE_HASH;
182
183 if (ubifs_authenticated(c)) {
184 sup_flags |= UBIFS_FLG_AUTHENTICATION;
185 sup->hash_algo = cpu_to_le16(c->auth_hash_algo);
186 err = ubifs_hmac_wkm(c, sup->hmac_wkm);
187 if (err)
188 goto out;
189 } else {
190 sup->hash_algo = cpu_to_le16(0xffff);
191 }
192
193 sup->ch.node_type = UBIFS_SB_NODE;
194 sup->key_hash = UBIFS_KEY_HASH_R5;
195 sup->flags = cpu_to_le32(sup_flags);
196 sup->min_io_size = cpu_to_le32(c->min_io_size);
197 sup->leb_size = cpu_to_le32(c->leb_size);
198 sup->leb_cnt = cpu_to_le32(c->leb_cnt);
199 sup->max_leb_cnt = cpu_to_le32(c->max_leb_cnt);
200 sup->max_bud_bytes = cpu_to_le64(tmp64);
201 sup->log_lebs = cpu_to_le32(log_lebs);
202 sup->lpt_lebs = cpu_to_le32(lpt_lebs);
203 sup->orph_lebs = cpu_to_le32(orph_lebs);
204 sup->jhead_cnt = cpu_to_le32(DEFAULT_JHEADS_CNT);
205 sup->fanout = cpu_to_le32(DEFAULT_FANOUT);
206 sup->lsave_cnt = cpu_to_le32(c->lsave_cnt);
207 sup->fmt_version = cpu_to_le32(ubifs_default_version);
208 sup->time_gran = cpu_to_le32(DEFAULT_TIME_GRAN);
209 if (c->mount_opts.override_compr)
210 sup->default_compr = cpu_to_le16(c->mount_opts.compr_type);
211 else
212 sup->default_compr = cpu_to_le16(get_default_compressor(c));
213
214 generate_random_uuid(sup->uuid);
215
216 main_bytes = (long long)main_lebs * c->leb_size;
217 tmp64 = div_u64(main_bytes * DEFAULT_RP_PERCENT, 100);
218 if (tmp64 > DEFAULT_MAX_RP_SIZE)
219 tmp64 = DEFAULT_MAX_RP_SIZE;
220 sup->rp_size = cpu_to_le64(tmp64);
221 sup->ro_compat_version = cpu_to_le32(UBIFS_RO_COMPAT_VERSION);
222
223 dbg_gen("default superblock created at LEB 0:0");
224
225 /* Create default master node */
226
227 mst->ch.node_type = UBIFS_MST_NODE;
228 mst->log_lnum = cpu_to_le32(UBIFS_LOG_LNUM);
229 mst->highest_inum = cpu_to_le64(UBIFS_FIRST_INO);
230 mst->cmt_no = 0;
231 mst->root_lnum = cpu_to_le32(main_first + DEFAULT_IDX_LEB);
232 mst->root_offs = 0;
233 tmp = ubifs_idx_node_sz(c, 1);
234 mst->root_len = cpu_to_le32(tmp);
235 mst->gc_lnum = cpu_to_le32(main_first + DEFAULT_GC_LEB);
236 mst->ihead_lnum = cpu_to_le32(main_first + DEFAULT_IDX_LEB);
237 mst->ihead_offs = cpu_to_le32(ALIGN(tmp, c->min_io_size));
238 mst->index_size = cpu_to_le64(ALIGN(tmp, 8));
239 mst->lpt_lnum = cpu_to_le32(c->lpt_lnum);
240 mst->lpt_offs = cpu_to_le32(c->lpt_offs);
241 mst->nhead_lnum = cpu_to_le32(c->nhead_lnum);
242 mst->nhead_offs = cpu_to_le32(c->nhead_offs);
243 mst->ltab_lnum = cpu_to_le32(c->ltab_lnum);
244 mst->ltab_offs = cpu_to_le32(c->ltab_offs);
245 mst->lsave_lnum = cpu_to_le32(c->lsave_lnum);
246 mst->lsave_offs = cpu_to_le32(c->lsave_offs);
247 mst->lscan_lnum = cpu_to_le32(main_first);
248 mst->empty_lebs = cpu_to_le32(main_lebs - 2);
249 mst->idx_lebs = cpu_to_le32(1);
250 mst->leb_cnt = cpu_to_le32(c->leb_cnt);
251 ubifs_copy_hash(c, hash_lpt, mst->hash_lpt);
252
253 /* Calculate lprops statistics */
254 tmp64 = main_bytes;
255 tmp64 -= ALIGN(ubifs_idx_node_sz(c, 1), c->min_io_size);
256 tmp64 -= ALIGN(UBIFS_INO_NODE_SZ, c->min_io_size);
257 mst->total_free = cpu_to_le64(tmp64);
258
259 tmp64 = ALIGN(ubifs_idx_node_sz(c, 1), c->min_io_size);
260 ino_waste = ALIGN(UBIFS_INO_NODE_SZ, c->min_io_size) -
261 UBIFS_INO_NODE_SZ;
262 tmp64 += ino_waste;
263 tmp64 -= ALIGN(ubifs_idx_node_sz(c, 1), 8);
264 mst->total_dirty = cpu_to_le64(tmp64);
265
266 /* The indexing LEB does not contribute to dark space */
267 tmp64 = ((long long)(c->main_lebs - 1) * c->dark_wm);
268 mst->total_dark = cpu_to_le64(tmp64);
269
270 mst->total_used = cpu_to_le64(UBIFS_INO_NODE_SZ);
271
272 dbg_gen("default master node created at LEB %d:0", UBIFS_MST_LNUM);
273
274 /* Create the root indexing node */
275
276 c->key_fmt = UBIFS_SIMPLE_KEY_FMT;
277 c->key_hash = key_r5_hash;
278
279 idx->ch.node_type = UBIFS_IDX_NODE;
280 idx->child_cnt = cpu_to_le16(1);
281 ino_key_init(c, &key, UBIFS_ROOT_INO);
282 br = ubifs_idx_branch(c, idx, 0);
283 key_write_idx(c, &key, &br->key);
284 br->lnum = cpu_to_le32(main_first + DEFAULT_DATA_LEB);
285 br->len = cpu_to_le32(UBIFS_INO_NODE_SZ);
286
287 dbg_gen("default root indexing node created LEB %d:0",
288 main_first + DEFAULT_IDX_LEB);
289
290 /* Create default root inode */
291
292 ino_key_init_flash(c, &ino->key, UBIFS_ROOT_INO);
293 ino->ch.node_type = UBIFS_INO_NODE;
294 ino->creat_sqnum = cpu_to_le64(++c->max_sqnum);
295 ino->nlink = cpu_to_le32(2);
296
297 ktime_get_coarse_real_ts64(&ts);
298 tmp_le64 = cpu_to_le64(ts.tv_sec);
299 ino->atime_sec = tmp_le64;
300 ino->ctime_sec = tmp_le64;
301 ino->mtime_sec = tmp_le64;
302 ino->atime_nsec = 0;
303 ino->ctime_nsec = 0;
304 ino->mtime_nsec = 0;
305 ino->mode = cpu_to_le32(S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO);
306 ino->size = cpu_to_le64(UBIFS_INO_NODE_SZ);
307
308 /* Set compression enabled by default */
309 ino->flags = cpu_to_le32(UBIFS_COMPR_FL);
310
311 dbg_gen("root inode created at LEB %d:0",
312 main_first + DEFAULT_DATA_LEB);
313
314 /*
315 * The first node in the log has to be the commit start node. This is
316 * always the case during normal file-system operation. Write a fake
317 * commit start node to the log.
318 */
319
320 cs->ch.node_type = UBIFS_CS_NODE;
321
322 err = ubifs_write_node_hmac(c, sup, UBIFS_SB_NODE_SZ, 0, 0,
323 offsetof(struct ubifs_sb_node, hmac));
324 if (err)
325 goto out;
326
327 err = ubifs_write_node(c, ino, UBIFS_INO_NODE_SZ,
328 main_first + DEFAULT_DATA_LEB, 0);
329 if (err)
330 goto out;
331
332 ubifs_node_calc_hash(c, ino, hash);
333 ubifs_copy_hash(c, hash, ubifs_branch_hash(c, br));
334
335 err = ubifs_write_node(c, idx, idx_node_size, main_first + DEFAULT_IDX_LEB, 0);
336 if (err)
337 goto out;
338
339 ubifs_node_calc_hash(c, idx, hash);
340 ubifs_copy_hash(c, hash, mst->hash_root_idx);
341
342 err = ubifs_write_node_hmac(c, mst, UBIFS_MST_NODE_SZ, UBIFS_MST_LNUM, 0,
343 offsetof(struct ubifs_mst_node, hmac));
344 if (err)
345 goto out;
346
347 err = ubifs_write_node_hmac(c, mst, UBIFS_MST_NODE_SZ, UBIFS_MST_LNUM + 1,
348 0, offsetof(struct ubifs_mst_node, hmac));
349 if (err)
350 goto out;
351
352 err = ubifs_write_node(c, cs, UBIFS_CS_NODE_SZ, UBIFS_LOG_LNUM, 0);
353 if (err)
354 goto out;
355
356 ubifs_msg(c, "default file-system created");
357
358 err = 0;
359 out:
360 kfree(sup);
361 kfree(mst);
362 kfree(idx);
363 kfree(ino);
364 kfree(cs);
365
366 return err;
367 }
368
369 /**
370 * validate_sb - validate superblock node.
371 * @c: UBIFS file-system description object
372 * @sup: superblock node
373 *
374 * This function validates superblock node @sup. Since most of data was read
375 * from the superblock and stored in @c, the function validates fields in @c
376 * instead. Returns zero in case of success and %-EINVAL in case of validation
377 * failure.
378 */
validate_sb(struct ubifs_info * c,struct ubifs_sb_node * sup)379 static int validate_sb(struct ubifs_info *c, struct ubifs_sb_node *sup)
380 {
381 long long max_bytes;
382 int err = 1, min_leb_cnt;
383
384 if (!c->key_hash) {
385 err = 2;
386 goto failed;
387 }
388
389 if (sup->key_fmt != UBIFS_SIMPLE_KEY_FMT) {
390 err = 3;
391 goto failed;
392 }
393
394 if (le32_to_cpu(sup->min_io_size) != c->min_io_size) {
395 ubifs_err(c, "min. I/O unit mismatch: %d in superblock, %d real",
396 le32_to_cpu(sup->min_io_size), c->min_io_size);
397 goto failed;
398 }
399
400 if (le32_to_cpu(sup->leb_size) != c->leb_size) {
401 ubifs_err(c, "LEB size mismatch: %d in superblock, %d real",
402 le32_to_cpu(sup->leb_size), c->leb_size);
403 goto failed;
404 }
405
406 if (c->log_lebs < UBIFS_MIN_LOG_LEBS ||
407 c->lpt_lebs < UBIFS_MIN_LPT_LEBS ||
408 c->orph_lebs < UBIFS_MIN_ORPH_LEBS ||
409 c->main_lebs < UBIFS_MIN_MAIN_LEBS) {
410 err = 4;
411 goto failed;
412 }
413
414 /*
415 * Calculate minimum allowed amount of main area LEBs. This is very
416 * similar to %UBIFS_MIN_LEB_CNT, but we take into account real what we
417 * have just read from the superblock.
418 */
419 min_leb_cnt = UBIFS_SB_LEBS + UBIFS_MST_LEBS + c->log_lebs;
420 min_leb_cnt += c->lpt_lebs + c->orph_lebs + c->jhead_cnt + 6;
421
422 if (c->leb_cnt < min_leb_cnt || c->leb_cnt > c->vi.size) {
423 ubifs_err(c, "bad LEB count: %d in superblock, %d on UBI volume, %d minimum required",
424 c->leb_cnt, c->vi.size, min_leb_cnt);
425 goto failed;
426 }
427
428 if (c->max_leb_cnt < c->leb_cnt) {
429 ubifs_err(c, "max. LEB count %d less than LEB count %d",
430 c->max_leb_cnt, c->leb_cnt);
431 goto failed;
432 }
433
434 if (c->main_lebs < UBIFS_MIN_MAIN_LEBS) {
435 ubifs_err(c, "too few main LEBs count %d, must be at least %d",
436 c->main_lebs, UBIFS_MIN_MAIN_LEBS);
437 goto failed;
438 }
439
440 max_bytes = (long long)c->leb_size * UBIFS_MIN_BUD_LEBS;
441 if (c->max_bud_bytes < max_bytes) {
442 ubifs_err(c, "too small journal (%lld bytes), must be at least %lld bytes",
443 c->max_bud_bytes, max_bytes);
444 goto failed;
445 }
446
447 max_bytes = (long long)c->leb_size * c->main_lebs;
448 if (c->max_bud_bytes > max_bytes) {
449 ubifs_err(c, "too large journal size (%lld bytes), only %lld bytes available in the main area",
450 c->max_bud_bytes, max_bytes);
451 goto failed;
452 }
453
454 if (c->jhead_cnt < NONDATA_JHEADS_CNT + 1 ||
455 c->jhead_cnt > NONDATA_JHEADS_CNT + UBIFS_MAX_JHEADS) {
456 err = 9;
457 goto failed;
458 }
459
460 if (c->fanout < UBIFS_MIN_FANOUT ||
461 ubifs_idx_node_sz(c, c->fanout) > c->leb_size) {
462 err = 10;
463 goto failed;
464 }
465
466 if (c->lsave_cnt < 0 || (c->lsave_cnt > DEFAULT_LSAVE_CNT &&
467 c->lsave_cnt > c->max_leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS -
468 c->log_lebs - c->lpt_lebs - c->orph_lebs)) {
469 err = 11;
470 goto failed;
471 }
472
473 if (UBIFS_SB_LEBS + UBIFS_MST_LEBS + c->log_lebs + c->lpt_lebs +
474 c->orph_lebs + c->main_lebs != c->leb_cnt) {
475 err = 12;
476 goto failed;
477 }
478
479 if (c->default_compr >= UBIFS_COMPR_TYPES_CNT) {
480 err = 13;
481 goto failed;
482 }
483
484 if (c->rp_size < 0 || max_bytes < c->rp_size) {
485 err = 14;
486 goto failed;
487 }
488
489 if (le32_to_cpu(sup->time_gran) > 1000000000 ||
490 le32_to_cpu(sup->time_gran) < 1) {
491 err = 15;
492 goto failed;
493 }
494
495 if (!c->double_hash && c->fmt_version >= 5) {
496 err = 16;
497 goto failed;
498 }
499
500 if (c->encrypted && c->fmt_version < 5) {
501 err = 17;
502 goto failed;
503 }
504
505 return 0;
506
507 failed:
508 ubifs_err(c, "bad superblock, error %d", err);
509 ubifs_dump_node(c, sup, ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size));
510 return -EINVAL;
511 }
512
513 /**
514 * ubifs_read_sb_node - read superblock node.
515 * @c: UBIFS file-system description object
516 *
517 * This function returns a pointer to the superblock node or a negative error
518 * code. Note, the user of this function is responsible of kfree()'ing the
519 * returned superblock buffer.
520 */
ubifs_read_sb_node(struct ubifs_info * c)521 static struct ubifs_sb_node *ubifs_read_sb_node(struct ubifs_info *c)
522 {
523 struct ubifs_sb_node *sup;
524 int err;
525
526 sup = kmalloc(ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size), GFP_NOFS);
527 if (!sup)
528 return ERR_PTR(-ENOMEM);
529
530 err = ubifs_read_node(c, sup, UBIFS_SB_NODE, UBIFS_SB_NODE_SZ,
531 UBIFS_SB_LNUM, 0);
532 if (err) {
533 kfree(sup);
534 return ERR_PTR(err);
535 }
536
537 return sup;
538 }
539
authenticate_sb_node(struct ubifs_info * c,const struct ubifs_sb_node * sup)540 static int authenticate_sb_node(struct ubifs_info *c,
541 const struct ubifs_sb_node *sup)
542 {
543 unsigned int sup_flags = le32_to_cpu(sup->flags);
544 u8 hmac_wkm[UBIFS_HMAC_ARR_SZ];
545 int authenticated = !!(sup_flags & UBIFS_FLG_AUTHENTICATION);
546 int hash_algo;
547 int err;
548
549 if (c->authenticated && !authenticated) {
550 ubifs_err(c, "authenticated FS forced, but found FS without authentication");
551 return -EINVAL;
552 }
553
554 if (!c->authenticated && authenticated) {
555 ubifs_err(c, "authenticated FS found, but no key given");
556 return -EINVAL;
557 }
558
559 ubifs_msg(c, "Mounting in %sauthenticated mode",
560 c->authenticated ? "" : "un");
561
562 if (!c->authenticated)
563 return 0;
564
565 if (!IS_ENABLED(CONFIG_UBIFS_FS_AUTHENTICATION))
566 return -EOPNOTSUPP;
567
568 hash_algo = le16_to_cpu(sup->hash_algo);
569 if (hash_algo >= HASH_ALGO__LAST) {
570 ubifs_err(c, "superblock uses unknown hash algo %d",
571 hash_algo);
572 return -EINVAL;
573 }
574
575 if (strcmp(hash_algo_name[hash_algo], c->auth_hash_name)) {
576 ubifs_err(c, "This filesystem uses %s for hashing,"
577 " but %s is specified", hash_algo_name[hash_algo],
578 c->auth_hash_name);
579 return -EINVAL;
580 }
581
582 /*
583 * The super block node can either be authenticated by a HMAC or
584 * by a signature in a ubifs_sig_node directly following the
585 * super block node to support offline image creation.
586 */
587 if (ubifs_hmac_zero(c, sup->hmac)) {
588 err = ubifs_sb_verify_signature(c, sup);
589 } else {
590 err = ubifs_hmac_wkm(c, hmac_wkm);
591 if (err)
592 return err;
593 if (ubifs_check_hmac(c, hmac_wkm, sup->hmac_wkm)) {
594 ubifs_err(c, "provided key does not fit");
595 return -ENOKEY;
596 }
597 err = ubifs_node_verify_hmac(c, sup, sizeof(*sup),
598 offsetof(struct ubifs_sb_node,
599 hmac));
600 }
601
602 if (err)
603 ubifs_err(c, "Failed to authenticate superblock: %d", err);
604
605 return err;
606 }
607
608 /**
609 * ubifs_write_sb_node - write superblock node.
610 * @c: UBIFS file-system description object
611 * @sup: superblock node read with 'ubifs_read_sb_node()'
612 *
613 * This function returns %0 on success and a negative error code on failure.
614 */
ubifs_write_sb_node(struct ubifs_info * c,struct ubifs_sb_node * sup)615 int ubifs_write_sb_node(struct ubifs_info *c, struct ubifs_sb_node *sup)
616 {
617 int len = ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size);
618 int err;
619
620 err = ubifs_prepare_node_hmac(c, sup, UBIFS_SB_NODE_SZ,
621 offsetof(struct ubifs_sb_node, hmac), 1);
622 if (err)
623 return err;
624
625 return ubifs_leb_change(c, UBIFS_SB_LNUM, sup, len);
626 }
627
628 /**
629 * ubifs_read_superblock - read superblock.
630 * @c: UBIFS file-system description object
631 *
632 * This function finds, reads and checks the superblock. If an empty UBI volume
633 * is being mounted, this function creates default superblock. Returns zero in
634 * case of success, and a negative error code in case of failure.
635 */
ubifs_read_superblock(struct ubifs_info * c)636 int ubifs_read_superblock(struct ubifs_info *c)
637 {
638 int err, sup_flags;
639 struct ubifs_sb_node *sup;
640
641 if (c->empty) {
642 err = create_default_filesystem(c);
643 if (err)
644 return err;
645 }
646
647 sup = ubifs_read_sb_node(c);
648 if (IS_ERR(sup))
649 return PTR_ERR(sup);
650
651 c->sup_node = sup;
652
653 c->fmt_version = le32_to_cpu(sup->fmt_version);
654 c->ro_compat_version = le32_to_cpu(sup->ro_compat_version);
655
656 /*
657 * The software supports all previous versions but not future versions,
658 * due to the unavailability of time-travelling equipment.
659 */
660 if (c->fmt_version > UBIFS_FORMAT_VERSION) {
661 ubifs_assert(c, !c->ro_media || c->ro_mount);
662 if (!c->ro_mount ||
663 c->ro_compat_version > UBIFS_RO_COMPAT_VERSION) {
664 ubifs_err(c, "on-flash format version is w%d/r%d, but software only supports up to version w%d/r%d",
665 c->fmt_version, c->ro_compat_version,
666 UBIFS_FORMAT_VERSION,
667 UBIFS_RO_COMPAT_VERSION);
668 if (c->ro_compat_version <= UBIFS_RO_COMPAT_VERSION) {
669 ubifs_msg(c, "only R/O mounting is possible");
670 err = -EROFS;
671 } else
672 err = -EINVAL;
673 goto out;
674 }
675
676 /*
677 * The FS is mounted R/O, and the media format is
678 * R/O-compatible with the UBIFS implementation, so we can
679 * mount.
680 */
681 c->rw_incompat = 1;
682 }
683
684 if (c->fmt_version < 3) {
685 ubifs_err(c, "on-flash format version %d is not supported",
686 c->fmt_version);
687 err = -EINVAL;
688 goto out;
689 }
690
691 switch (sup->key_hash) {
692 case UBIFS_KEY_HASH_R5:
693 c->key_hash = key_r5_hash;
694 c->key_hash_type = UBIFS_KEY_HASH_R5;
695 break;
696
697 case UBIFS_KEY_HASH_TEST:
698 c->key_hash = key_test_hash;
699 c->key_hash_type = UBIFS_KEY_HASH_TEST;
700 break;
701 }
702
703 c->key_fmt = sup->key_fmt;
704
705 switch (c->key_fmt) {
706 case UBIFS_SIMPLE_KEY_FMT:
707 c->key_len = UBIFS_SK_LEN;
708 break;
709 default:
710 ubifs_err(c, "unsupported key format");
711 err = -EINVAL;
712 goto out;
713 }
714
715 c->leb_cnt = le32_to_cpu(sup->leb_cnt);
716 c->max_leb_cnt = le32_to_cpu(sup->max_leb_cnt);
717 c->max_bud_bytes = le64_to_cpu(sup->max_bud_bytes);
718 c->log_lebs = le32_to_cpu(sup->log_lebs);
719 c->lpt_lebs = le32_to_cpu(sup->lpt_lebs);
720 c->orph_lebs = le32_to_cpu(sup->orph_lebs);
721 c->jhead_cnt = le32_to_cpu(sup->jhead_cnt) + NONDATA_JHEADS_CNT;
722 c->fanout = le32_to_cpu(sup->fanout);
723 c->lsave_cnt = le32_to_cpu(sup->lsave_cnt);
724 c->rp_size = le64_to_cpu(sup->rp_size);
725 c->rp_uid = make_kuid(&init_user_ns, le32_to_cpu(sup->rp_uid));
726 c->rp_gid = make_kgid(&init_user_ns, le32_to_cpu(sup->rp_gid));
727 sup_flags = le32_to_cpu(sup->flags);
728 if (!c->mount_opts.override_compr)
729 c->default_compr = le16_to_cpu(sup->default_compr);
730
731 c->vfs_sb->s_time_gran = le32_to_cpu(sup->time_gran);
732 memcpy(&c->uuid, &sup->uuid, 16);
733 c->big_lpt = !!(sup_flags & UBIFS_FLG_BIGLPT);
734 c->space_fixup = !!(sup_flags & UBIFS_FLG_SPACE_FIXUP);
735 c->double_hash = !!(sup_flags & UBIFS_FLG_DOUBLE_HASH);
736 c->encrypted = !!(sup_flags & UBIFS_FLG_ENCRYPTION);
737
738 err = authenticate_sb_node(c, sup);
739 if (err)
740 goto out;
741
742 if ((sup_flags & ~UBIFS_FLG_MASK) != 0) {
743 ubifs_err(c, "Unknown feature flags found: %#x",
744 sup_flags & ~UBIFS_FLG_MASK);
745 err = -EINVAL;
746 goto out;
747 }
748
749 if (!IS_ENABLED(CONFIG_FS_ENCRYPTION) && c->encrypted) {
750 ubifs_err(c, "file system contains encrypted files but UBIFS"
751 " was built without crypto support.");
752 err = -EINVAL;
753 goto out;
754 }
755
756 /* Automatically increase file system size to the maximum size */
757 if (c->leb_cnt < c->vi.size && c->leb_cnt < c->max_leb_cnt) {
758 int old_leb_cnt = c->leb_cnt;
759
760 c->leb_cnt = min_t(int, c->max_leb_cnt, c->vi.size);
761 sup->leb_cnt = cpu_to_le32(c->leb_cnt);
762
763 c->superblock_need_write = 1;
764
765 dbg_mnt("Auto resizing from %d LEBs to %d LEBs",
766 old_leb_cnt, c->leb_cnt);
767 }
768
769 c->log_bytes = (long long)c->log_lebs * c->leb_size;
770 c->log_last = UBIFS_LOG_LNUM + c->log_lebs - 1;
771 c->lpt_first = UBIFS_LOG_LNUM + c->log_lebs;
772 c->lpt_last = c->lpt_first + c->lpt_lebs - 1;
773 c->orph_first = c->lpt_last + 1;
774 c->orph_last = c->orph_first + c->orph_lebs - 1;
775 c->main_lebs = c->leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS;
776 c->main_lebs -= c->log_lebs + c->lpt_lebs + c->orph_lebs;
777 c->main_first = c->leb_cnt - c->main_lebs;
778
779 err = validate_sb(c, sup);
780 out:
781 return err;
782 }
783
784 /**
785 * fixup_leb - fixup/unmap an LEB containing free space.
786 * @c: UBIFS file-system description object
787 * @lnum: the LEB number to fix up
788 * @len: number of used bytes in LEB (starting at offset 0)
789 *
790 * This function reads the contents of the given LEB number @lnum, then fixes
791 * it up, so that empty min. I/O units in the end of LEB are actually erased on
792 * flash (rather than being just all-0xff real data). If the LEB is completely
793 * empty, it is simply unmapped.
794 */
fixup_leb(struct ubifs_info * c,int lnum,int len)795 static int fixup_leb(struct ubifs_info *c, int lnum, int len)
796 {
797 int err;
798
799 ubifs_assert(c, len >= 0);
800 ubifs_assert(c, len % c->min_io_size == 0);
801 ubifs_assert(c, len < c->leb_size);
802
803 if (len == 0) {
804 dbg_mnt("unmap empty LEB %d", lnum);
805 return ubifs_leb_unmap(c, lnum);
806 }
807
808 dbg_mnt("fixup LEB %d, data len %d", lnum, len);
809 err = ubifs_leb_read(c, lnum, c->sbuf, 0, len, 1);
810 if (err)
811 return err;
812
813 return ubifs_leb_change(c, lnum, c->sbuf, len);
814 }
815
816 /**
817 * fixup_free_space - find & remap all LEBs containing free space.
818 * @c: UBIFS file-system description object
819 *
820 * This function walks through all LEBs in the filesystem and fiexes up those
821 * containing free/empty space.
822 */
fixup_free_space(struct ubifs_info * c)823 static int fixup_free_space(struct ubifs_info *c)
824 {
825 int lnum, err = 0;
826 struct ubifs_lprops *lprops;
827
828 ubifs_get_lprops(c);
829
830 /* Fixup LEBs in the master area */
831 for (lnum = UBIFS_MST_LNUM; lnum < UBIFS_LOG_LNUM; lnum++) {
832 err = fixup_leb(c, lnum, c->mst_offs + c->mst_node_alsz);
833 if (err)
834 goto out;
835 }
836
837 /* Unmap unused log LEBs */
838 lnum = ubifs_next_log_lnum(c, c->lhead_lnum);
839 while (lnum != c->ltail_lnum) {
840 err = fixup_leb(c, lnum, 0);
841 if (err)
842 goto out;
843 lnum = ubifs_next_log_lnum(c, lnum);
844 }
845
846 /*
847 * Fixup the log head which contains the only a CS node at the
848 * beginning.
849 */
850 err = fixup_leb(c, c->lhead_lnum,
851 ALIGN(UBIFS_CS_NODE_SZ, c->min_io_size));
852 if (err)
853 goto out;
854
855 /* Fixup LEBs in the LPT area */
856 for (lnum = c->lpt_first; lnum <= c->lpt_last; lnum++) {
857 int free = c->ltab[lnum - c->lpt_first].free;
858
859 if (free > 0) {
860 err = fixup_leb(c, lnum, c->leb_size - free);
861 if (err)
862 goto out;
863 }
864 }
865
866 /* Unmap LEBs in the orphans area */
867 for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
868 err = fixup_leb(c, lnum, 0);
869 if (err)
870 goto out;
871 }
872
873 /* Fixup LEBs in the main area */
874 for (lnum = c->main_first; lnum < c->leb_cnt; lnum++) {
875 lprops = ubifs_lpt_lookup(c, lnum);
876 if (IS_ERR(lprops)) {
877 err = PTR_ERR(lprops);
878 goto out;
879 }
880
881 if (lprops->free > 0) {
882 err = fixup_leb(c, lnum, c->leb_size - lprops->free);
883 if (err)
884 goto out;
885 }
886 }
887
888 out:
889 ubifs_release_lprops(c);
890 return err;
891 }
892
893 /**
894 * ubifs_fixup_free_space - find & fix all LEBs with free space.
895 * @c: UBIFS file-system description object
896 *
897 * This function fixes up LEBs containing free space on first mount, if the
898 * appropriate flag was set when the FS was created. Each LEB with one or more
899 * empty min. I/O unit (i.e. free-space-count > 0) is re-written, to make sure
900 * the free space is actually erased. E.g., this is necessary for some NAND
901 * chips, since the free space may have been programmed like real "0xff" data
902 * (generating a non-0xff ECC), causing future writes to the not-really-erased
903 * NAND pages to behave badly. After the space is fixed up, the superblock flag
904 * is cleared, so that this is skipped for all future mounts.
905 */
ubifs_fixup_free_space(struct ubifs_info * c)906 int ubifs_fixup_free_space(struct ubifs_info *c)
907 {
908 int err;
909 struct ubifs_sb_node *sup = c->sup_node;
910
911 ubifs_assert(c, c->space_fixup);
912 ubifs_assert(c, !c->ro_mount);
913
914 ubifs_msg(c, "start fixing up free space");
915
916 err = fixup_free_space(c);
917 if (err)
918 return err;
919
920 /* Free-space fixup is no longer required */
921 c->space_fixup = 0;
922 sup->flags &= cpu_to_le32(~UBIFS_FLG_SPACE_FIXUP);
923
924 c->superblock_need_write = 1;
925
926 ubifs_msg(c, "free space fixup complete");
927 return err;
928 }
929
ubifs_enable_encryption(struct ubifs_info * c)930 int ubifs_enable_encryption(struct ubifs_info *c)
931 {
932 int err;
933 struct ubifs_sb_node *sup = c->sup_node;
934
935 if (!IS_ENABLED(CONFIG_FS_ENCRYPTION))
936 return -EOPNOTSUPP;
937
938 if (c->encrypted)
939 return 0;
940
941 if (c->ro_mount || c->ro_media)
942 return -EROFS;
943
944 if (c->fmt_version < 5) {
945 ubifs_err(c, "on-flash format version 5 is needed for encryption");
946 return -EINVAL;
947 }
948
949 sup->flags |= cpu_to_le32(UBIFS_FLG_ENCRYPTION);
950
951 err = ubifs_write_sb_node(c, sup);
952 if (!err)
953 c->encrypted = 1;
954
955 return err;
956 }
957