xref: /openbmc/linux/fs/ubifs/sb.c (revision 7fd53f41)
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 	struct timespec64 ts;
88 	u8 hash[UBIFS_HASH_ARR_SZ];
89 	u8 hash_lpt[UBIFS_HASH_ARR_SZ];
90 
91 	/* Some functions called from here depend on the @c->key_len filed */
92 	c->key_len = UBIFS_SK_LEN;
93 
94 	/*
95 	 * First of all, we have to calculate default file-system geometry -
96 	 * log size, journal size, etc.
97 	 */
98 	if (c->leb_cnt < 0x7FFFFFFF / DEFAULT_JNL_PERCENT)
99 		/* We can first multiply then divide and have no overflow */
100 		jnl_lebs = c->leb_cnt * DEFAULT_JNL_PERCENT / 100;
101 	else
102 		jnl_lebs = (c->leb_cnt / 100) * DEFAULT_JNL_PERCENT;
103 
104 	if (jnl_lebs < UBIFS_MIN_JNL_LEBS)
105 		jnl_lebs = UBIFS_MIN_JNL_LEBS;
106 	if (jnl_lebs * c->leb_size > DEFAULT_MAX_JNL)
107 		jnl_lebs = DEFAULT_MAX_JNL / c->leb_size;
108 
109 	/*
110 	 * The log should be large enough to fit reference nodes for all bud
111 	 * LEBs. Because buds do not have to start from the beginning of LEBs
112 	 * (half of the LEB may contain committed data), the log should
113 	 * generally be larger, make it twice as large.
114 	 */
115 	tmp = 2 * (c->ref_node_alsz * jnl_lebs) + c->leb_size - 1;
116 	log_lebs = tmp / c->leb_size;
117 	/* Plus one LEB reserved for commit */
118 	log_lebs += 1;
119 	if (c->leb_cnt - min_leb_cnt > 8) {
120 		/* And some extra space to allow writes while committing */
121 		log_lebs += 1;
122 		min_leb_cnt += 1;
123 	}
124 
125 	max_buds = jnl_lebs - log_lebs;
126 	if (max_buds < UBIFS_MIN_BUD_LEBS)
127 		max_buds = UBIFS_MIN_BUD_LEBS;
128 
129 	/*
130 	 * Orphan nodes are stored in a separate area. One node can store a lot
131 	 * of orphan inode numbers, but when new orphan comes we just add a new
132 	 * orphan node. At some point the nodes are consolidated into one
133 	 * orphan node.
134 	 */
135 	orph_lebs = UBIFS_MIN_ORPH_LEBS;
136 	if (c->leb_cnt - min_leb_cnt > 1)
137 		/*
138 		 * For debugging purposes it is better to have at least 2
139 		 * orphan LEBs, because the orphan subsystem would need to do
140 		 * consolidations and would be stressed more.
141 		 */
142 		orph_lebs += 1;
143 
144 	main_lebs = c->leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS - log_lebs;
145 	main_lebs -= orph_lebs;
146 
147 	lpt_first = UBIFS_LOG_LNUM + log_lebs;
148 	c->lsave_cnt = DEFAULT_LSAVE_CNT;
149 	c->max_leb_cnt = c->leb_cnt;
150 	err = ubifs_create_dflt_lpt(c, &main_lebs, lpt_first, &lpt_lebs,
151 				    &big_lpt, hash_lpt);
152 	if (err)
153 		return err;
154 
155 	dbg_gen("LEB Properties Tree created (LEBs %d-%d)", lpt_first,
156 		lpt_first + lpt_lebs - 1);
157 
158 	main_first = c->leb_cnt - main_lebs;
159 
160 	sup = kzalloc(ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size), GFP_KERNEL);
161 	mst = kzalloc(c->mst_node_alsz, GFP_KERNEL);
162 	idx_node_size = ubifs_idx_node_sz(c, 1);
163 	idx = kzalloc(ALIGN(idx_node_size, c->min_io_size), GFP_KERNEL);
164 	ino = kzalloc(ALIGN(UBIFS_INO_NODE_SZ, c->min_io_size), GFP_KERNEL);
165 	cs = kzalloc(ALIGN(UBIFS_CS_NODE_SZ, c->min_io_size), GFP_KERNEL);
166 
167 	if (!sup || !mst || !idx || !ino || !cs) {
168 		err = -ENOMEM;
169 		goto out;
170 	}
171 
172 	/* Create default superblock */
173 
174 	tmp64 = (long long)max_buds * c->leb_size;
175 	if (big_lpt)
176 		sup_flags |= UBIFS_FLG_BIGLPT;
177 	if (ubifs_default_version > 4)
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 = cpu_to_le16(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_default_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_coarse_real_ts64(&ts);
295 	tmp_le64 = cpu_to_le64(ts.tv_sec);
296 	ino->atime_sec   = tmp_le64;
297 	ino->ctime_sec   = tmp_le64;
298 	ino->mtime_sec   = tmp_le64;
299 	ino->atime_nsec  = 0;
300 	ino->ctime_nsec  = 0;
301 	ino->mtime_nsec  = 0;
302 	ino->mode = cpu_to_le32(S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO);
303 	ino->size = cpu_to_le64(UBIFS_INO_NODE_SZ);
304 
305 	/* Set compression enabled by default */
306 	ino->flags = cpu_to_le32(UBIFS_COMPR_FL);
307 
308 	dbg_gen("root inode created at LEB %d:0",
309 		main_first + DEFAULT_DATA_LEB);
310 
311 	/*
312 	 * The first node in the log has to be the commit start node. This is
313 	 * always the case during normal file-system operation. Write a fake
314 	 * commit start node to the log.
315 	 */
316 
317 	cs->ch.node_type = UBIFS_CS_NODE;
318 
319 	err = ubifs_write_node_hmac(c, sup, UBIFS_SB_NODE_SZ, 0, 0,
320 				    offsetof(struct ubifs_sb_node, hmac));
321 	if (err)
322 		goto out;
323 
324 	err = ubifs_write_node(c, ino, UBIFS_INO_NODE_SZ,
325 			       main_first + DEFAULT_DATA_LEB, 0);
326 	if (err)
327 		goto out;
328 
329 	ubifs_node_calc_hash(c, ino, hash);
330 	ubifs_copy_hash(c, hash, ubifs_branch_hash(c, br));
331 
332 	err = ubifs_write_node(c, idx, idx_node_size, main_first + DEFAULT_IDX_LEB, 0);
333 	if (err)
334 		goto out;
335 
336 	ubifs_node_calc_hash(c, idx, hash);
337 	ubifs_copy_hash(c, hash, mst->hash_root_idx);
338 
339 	err = ubifs_write_node_hmac(c, mst, UBIFS_MST_NODE_SZ, UBIFS_MST_LNUM, 0,
340 		offsetof(struct ubifs_mst_node, hmac));
341 	if (err)
342 		goto out;
343 
344 	err = ubifs_write_node_hmac(c, mst, UBIFS_MST_NODE_SZ, UBIFS_MST_LNUM + 1,
345 			       0, offsetof(struct ubifs_mst_node, hmac));
346 	if (err)
347 		goto out;
348 
349 	err = ubifs_write_node(c, cs, UBIFS_CS_NODE_SZ, UBIFS_LOG_LNUM, 0);
350 	if (err)
351 		goto out;
352 
353 	ubifs_msg(c, "default file-system created");
354 
355 	err = 0;
356 out:
357 	kfree(sup);
358 	kfree(mst);
359 	kfree(idx);
360 	kfree(ino);
361 	kfree(cs);
362 
363 	return err;
364 }
365 
366 /**
367  * validate_sb - validate superblock node.
368  * @c: UBIFS file-system description object
369  * @sup: superblock node
370  *
371  * This function validates superblock node @sup. Since most of data was read
372  * from the superblock and stored in @c, the function validates fields in @c
373  * instead. Returns zero in case of success and %-EINVAL in case of validation
374  * failure.
375  */
376 static int validate_sb(struct ubifs_info *c, struct ubifs_sb_node *sup)
377 {
378 	long long max_bytes;
379 	int err = 1, min_leb_cnt;
380 
381 	if (!c->key_hash) {
382 		err = 2;
383 		goto failed;
384 	}
385 
386 	if (sup->key_fmt != UBIFS_SIMPLE_KEY_FMT) {
387 		err = 3;
388 		goto failed;
389 	}
390 
391 	if (le32_to_cpu(sup->min_io_size) != c->min_io_size) {
392 		ubifs_err(c, "min. I/O unit mismatch: %d in superblock, %d real",
393 			  le32_to_cpu(sup->min_io_size), c->min_io_size);
394 		goto failed;
395 	}
396 
397 	if (le32_to_cpu(sup->leb_size) != c->leb_size) {
398 		ubifs_err(c, "LEB size mismatch: %d in superblock, %d real",
399 			  le32_to_cpu(sup->leb_size), c->leb_size);
400 		goto failed;
401 	}
402 
403 	if (c->log_lebs < UBIFS_MIN_LOG_LEBS ||
404 	    c->lpt_lebs < UBIFS_MIN_LPT_LEBS ||
405 	    c->orph_lebs < UBIFS_MIN_ORPH_LEBS ||
406 	    c->main_lebs < UBIFS_MIN_MAIN_LEBS) {
407 		err = 4;
408 		goto failed;
409 	}
410 
411 	/*
412 	 * Calculate minimum allowed amount of main area LEBs. This is very
413 	 * similar to %UBIFS_MIN_LEB_CNT, but we take into account real what we
414 	 * have just read from the superblock.
415 	 */
416 	min_leb_cnt = UBIFS_SB_LEBS + UBIFS_MST_LEBS + c->log_lebs;
417 	min_leb_cnt += c->lpt_lebs + c->orph_lebs + c->jhead_cnt + 6;
418 
419 	if (c->leb_cnt < min_leb_cnt || c->leb_cnt > c->vi.size) {
420 		ubifs_err(c, "bad LEB count: %d in superblock, %d on UBI volume, %d minimum required",
421 			  c->leb_cnt, c->vi.size, min_leb_cnt);
422 		goto failed;
423 	}
424 
425 	if (c->max_leb_cnt < c->leb_cnt) {
426 		ubifs_err(c, "max. LEB count %d less than LEB count %d",
427 			  c->max_leb_cnt, c->leb_cnt);
428 		goto failed;
429 	}
430 
431 	if (c->main_lebs < UBIFS_MIN_MAIN_LEBS) {
432 		ubifs_err(c, "too few main LEBs count %d, must be at least %d",
433 			  c->main_lebs, UBIFS_MIN_MAIN_LEBS);
434 		goto failed;
435 	}
436 
437 	max_bytes = (long long)c->leb_size * UBIFS_MIN_BUD_LEBS;
438 	if (c->max_bud_bytes < max_bytes) {
439 		ubifs_err(c, "too small journal (%lld bytes), must be at least %lld bytes",
440 			  c->max_bud_bytes, max_bytes);
441 		goto failed;
442 	}
443 
444 	max_bytes = (long long)c->leb_size * c->main_lebs;
445 	if (c->max_bud_bytes > max_bytes) {
446 		ubifs_err(c, "too large journal size (%lld bytes), only %lld bytes available in the main area",
447 			  c->max_bud_bytes, max_bytes);
448 		goto failed;
449 	}
450 
451 	if (c->jhead_cnt < NONDATA_JHEADS_CNT + 1 ||
452 	    c->jhead_cnt > NONDATA_JHEADS_CNT + UBIFS_MAX_JHEADS) {
453 		err = 9;
454 		goto failed;
455 	}
456 
457 	if (c->fanout < UBIFS_MIN_FANOUT ||
458 	    ubifs_idx_node_sz(c, c->fanout) > c->leb_size) {
459 		err = 10;
460 		goto failed;
461 	}
462 
463 	if (c->lsave_cnt < 0 || (c->lsave_cnt > DEFAULT_LSAVE_CNT &&
464 	    c->lsave_cnt > c->max_leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS -
465 	    c->log_lebs - c->lpt_lebs - c->orph_lebs)) {
466 		err = 11;
467 		goto failed;
468 	}
469 
470 	if (UBIFS_SB_LEBS + UBIFS_MST_LEBS + c->log_lebs + c->lpt_lebs +
471 	    c->orph_lebs + c->main_lebs != c->leb_cnt) {
472 		err = 12;
473 		goto failed;
474 	}
475 
476 	if (c->default_compr >= UBIFS_COMPR_TYPES_CNT) {
477 		err = 13;
478 		goto failed;
479 	}
480 
481 	if (c->rp_size < 0 || max_bytes < c->rp_size) {
482 		err = 14;
483 		goto failed;
484 	}
485 
486 	if (le32_to_cpu(sup->time_gran) > 1000000000 ||
487 	    le32_to_cpu(sup->time_gran) < 1) {
488 		err = 15;
489 		goto failed;
490 	}
491 
492 	if (!c->double_hash && c->fmt_version >= 5) {
493 		err = 16;
494 		goto failed;
495 	}
496 
497 	if (c->encrypted && c->fmt_version < 5) {
498 		err = 17;
499 		goto failed;
500 	}
501 
502 	return 0;
503 
504 failed:
505 	ubifs_err(c, "bad superblock, error %d", err);
506 	ubifs_dump_node(c, sup, ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size));
507 	return -EINVAL;
508 }
509 
510 /**
511  * ubifs_read_sb_node - read superblock node.
512  * @c: UBIFS file-system description object
513  *
514  * This function returns a pointer to the superblock node or a negative error
515  * code. Note, the user of this function is responsible of kfree()'ing the
516  * returned superblock buffer.
517  */
518 static struct ubifs_sb_node *ubifs_read_sb_node(struct ubifs_info *c)
519 {
520 	struct ubifs_sb_node *sup;
521 	int err;
522 
523 	sup = kmalloc(ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size), GFP_NOFS);
524 	if (!sup)
525 		return ERR_PTR(-ENOMEM);
526 
527 	err = ubifs_read_node(c, sup, UBIFS_SB_NODE, UBIFS_SB_NODE_SZ,
528 			      UBIFS_SB_LNUM, 0);
529 	if (err) {
530 		kfree(sup);
531 		return ERR_PTR(err);
532 	}
533 
534 	return sup;
535 }
536 
537 static int authenticate_sb_node(struct ubifs_info *c,
538 				const struct ubifs_sb_node *sup)
539 {
540 	unsigned int sup_flags = le32_to_cpu(sup->flags);
541 	u8 hmac_wkm[UBIFS_HMAC_ARR_SZ];
542 	int authenticated = !!(sup_flags & UBIFS_FLG_AUTHENTICATION);
543 	int hash_algo;
544 	int err;
545 
546 	if (c->authenticated && !authenticated) {
547 		ubifs_err(c, "authenticated FS forced, but found FS without authentication");
548 		return -EINVAL;
549 	}
550 
551 	if (!c->authenticated && authenticated) {
552 		ubifs_err(c, "authenticated FS found, but no key given");
553 		return -EINVAL;
554 	}
555 
556 	ubifs_msg(c, "Mounting in %sauthenticated mode",
557 		  c->authenticated ? "" : "un");
558 
559 	if (!c->authenticated)
560 		return 0;
561 
562 	if (!IS_ENABLED(CONFIG_UBIFS_FS_AUTHENTICATION))
563 		return -EOPNOTSUPP;
564 
565 	hash_algo = le16_to_cpu(sup->hash_algo);
566 	if (hash_algo >= HASH_ALGO__LAST) {
567 		ubifs_err(c, "superblock uses unknown hash algo %d",
568 			  hash_algo);
569 		return -EINVAL;
570 	}
571 
572 	if (strcmp(hash_algo_name[hash_algo], c->auth_hash_name)) {
573 		ubifs_err(c, "This filesystem uses %s for hashing,"
574 			     " but %s is specified", hash_algo_name[hash_algo],
575 			     c->auth_hash_name);
576 		return -EINVAL;
577 	}
578 
579 	/*
580 	 * The super block node can either be authenticated by a HMAC or
581 	 * by a signature in a ubifs_sig_node directly following the
582 	 * super block node to support offline image creation.
583 	 */
584 	if (ubifs_hmac_zero(c, sup->hmac)) {
585 		err = ubifs_sb_verify_signature(c, sup);
586 	} else {
587 		err = ubifs_hmac_wkm(c, hmac_wkm);
588 		if (err)
589 			return err;
590 		if (ubifs_check_hmac(c, hmac_wkm, sup->hmac_wkm)) {
591 			ubifs_err(c, "provided key does not fit");
592 			return -ENOKEY;
593 		}
594 		err = ubifs_node_verify_hmac(c, sup, sizeof(*sup),
595 					     offsetof(struct ubifs_sb_node,
596 						      hmac));
597 	}
598 
599 	if (err)
600 		ubifs_err(c, "Failed to authenticate superblock: %d", err);
601 
602 	return err;
603 }
604 
605 /**
606  * ubifs_write_sb_node - write superblock node.
607  * @c: UBIFS file-system description object
608  * @sup: superblock node read with 'ubifs_read_sb_node()'
609  *
610  * This function returns %0 on success and a negative error code on failure.
611  */
612 int ubifs_write_sb_node(struct ubifs_info *c, struct ubifs_sb_node *sup)
613 {
614 	int len = ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size);
615 	int err;
616 
617 	err = ubifs_prepare_node_hmac(c, sup, UBIFS_SB_NODE_SZ,
618 				      offsetof(struct ubifs_sb_node, hmac), 1);
619 	if (err)
620 		return err;
621 
622 	return ubifs_leb_change(c, UBIFS_SB_LNUM, sup, len);
623 }
624 
625 /**
626  * ubifs_read_superblock - read superblock.
627  * @c: UBIFS file-system description object
628  *
629  * This function finds, reads and checks the superblock. If an empty UBI volume
630  * is being mounted, this function creates default superblock. Returns zero in
631  * case of success, and a negative error code in case of failure.
632  */
633 int ubifs_read_superblock(struct ubifs_info *c)
634 {
635 	int err, sup_flags;
636 	struct ubifs_sb_node *sup;
637 
638 	if (c->empty) {
639 		err = create_default_filesystem(c);
640 		if (err)
641 			return err;
642 	}
643 
644 	sup = ubifs_read_sb_node(c);
645 	if (IS_ERR(sup))
646 		return PTR_ERR(sup);
647 
648 	c->sup_node = sup;
649 
650 	c->fmt_version = le32_to_cpu(sup->fmt_version);
651 	c->ro_compat_version = le32_to_cpu(sup->ro_compat_version);
652 
653 	/*
654 	 * The software supports all previous versions but not future versions,
655 	 * due to the unavailability of time-travelling equipment.
656 	 */
657 	if (c->fmt_version > UBIFS_FORMAT_VERSION) {
658 		ubifs_assert(c, !c->ro_media || c->ro_mount);
659 		if (!c->ro_mount ||
660 		    c->ro_compat_version > UBIFS_RO_COMPAT_VERSION) {
661 			ubifs_err(c, "on-flash format version is w%d/r%d, but software only supports up to version w%d/r%d",
662 				  c->fmt_version, c->ro_compat_version,
663 				  UBIFS_FORMAT_VERSION,
664 				  UBIFS_RO_COMPAT_VERSION);
665 			if (c->ro_compat_version <= UBIFS_RO_COMPAT_VERSION) {
666 				ubifs_msg(c, "only R/O mounting is possible");
667 				err = -EROFS;
668 			} else
669 				err = -EINVAL;
670 			goto out;
671 		}
672 
673 		/*
674 		 * The FS is mounted R/O, and the media format is
675 		 * R/O-compatible with the UBIFS implementation, so we can
676 		 * mount.
677 		 */
678 		c->rw_incompat = 1;
679 	}
680 
681 	if (c->fmt_version < 3) {
682 		ubifs_err(c, "on-flash format version %d is not supported",
683 			  c->fmt_version);
684 		err = -EINVAL;
685 		goto out;
686 	}
687 
688 	switch (sup->key_hash) {
689 	case UBIFS_KEY_HASH_R5:
690 		c->key_hash = key_r5_hash;
691 		c->key_hash_type = UBIFS_KEY_HASH_R5;
692 		break;
693 
694 	case UBIFS_KEY_HASH_TEST:
695 		c->key_hash = key_test_hash;
696 		c->key_hash_type = UBIFS_KEY_HASH_TEST;
697 		break;
698 	}
699 
700 	c->key_fmt = sup->key_fmt;
701 
702 	switch (c->key_fmt) {
703 	case UBIFS_SIMPLE_KEY_FMT:
704 		c->key_len = UBIFS_SK_LEN;
705 		break;
706 	default:
707 		ubifs_err(c, "unsupported key format");
708 		err = -EINVAL;
709 		goto out;
710 	}
711 
712 	c->leb_cnt       = le32_to_cpu(sup->leb_cnt);
713 	c->max_leb_cnt   = le32_to_cpu(sup->max_leb_cnt);
714 	c->max_bud_bytes = le64_to_cpu(sup->max_bud_bytes);
715 	c->log_lebs      = le32_to_cpu(sup->log_lebs);
716 	c->lpt_lebs      = le32_to_cpu(sup->lpt_lebs);
717 	c->orph_lebs     = le32_to_cpu(sup->orph_lebs);
718 	c->jhead_cnt     = le32_to_cpu(sup->jhead_cnt) + NONDATA_JHEADS_CNT;
719 	c->fanout        = le32_to_cpu(sup->fanout);
720 	c->lsave_cnt     = le32_to_cpu(sup->lsave_cnt);
721 	c->rp_size       = le64_to_cpu(sup->rp_size);
722 	c->rp_uid        = make_kuid(&init_user_ns, le32_to_cpu(sup->rp_uid));
723 	c->rp_gid        = make_kgid(&init_user_ns, le32_to_cpu(sup->rp_gid));
724 	sup_flags        = le32_to_cpu(sup->flags);
725 	if (!c->mount_opts.override_compr)
726 		c->default_compr = le16_to_cpu(sup->default_compr);
727 
728 	c->vfs_sb->s_time_gran = le32_to_cpu(sup->time_gran);
729 	memcpy(&c->uuid, &sup->uuid, 16);
730 	c->big_lpt = !!(sup_flags & UBIFS_FLG_BIGLPT);
731 	c->space_fixup = !!(sup_flags & UBIFS_FLG_SPACE_FIXUP);
732 	c->double_hash = !!(sup_flags & UBIFS_FLG_DOUBLE_HASH);
733 	c->encrypted = !!(sup_flags & UBIFS_FLG_ENCRYPTION);
734 
735 	err = authenticate_sb_node(c, sup);
736 	if (err)
737 		goto out;
738 
739 	if ((sup_flags & ~UBIFS_FLG_MASK) != 0) {
740 		ubifs_err(c, "Unknown feature flags found: %#x",
741 			  sup_flags & ~UBIFS_FLG_MASK);
742 		err = -EINVAL;
743 		goto out;
744 	}
745 
746 	if (!IS_ENABLED(CONFIG_FS_ENCRYPTION) && c->encrypted) {
747 		ubifs_err(c, "file system contains encrypted files but UBIFS"
748 			     " was built without crypto support.");
749 		err = -EINVAL;
750 		goto out;
751 	}
752 
753 	/* Automatically increase file system size to the maximum size */
754 	if (c->leb_cnt < c->vi.size && c->leb_cnt < c->max_leb_cnt) {
755 		int old_leb_cnt = c->leb_cnt;
756 
757 		c->leb_cnt = min_t(int, c->max_leb_cnt, c->vi.size);
758 		sup->leb_cnt = cpu_to_le32(c->leb_cnt);
759 
760 		c->superblock_need_write = 1;
761 
762 		dbg_mnt("Auto resizing from %d LEBs to %d LEBs",
763 			old_leb_cnt, c->leb_cnt);
764 	}
765 
766 	c->log_bytes = (long long)c->log_lebs * c->leb_size;
767 	c->log_last = UBIFS_LOG_LNUM + c->log_lebs - 1;
768 	c->lpt_first = UBIFS_LOG_LNUM + c->log_lebs;
769 	c->lpt_last = c->lpt_first + c->lpt_lebs - 1;
770 	c->orph_first = c->lpt_last + 1;
771 	c->orph_last = c->orph_first + c->orph_lebs - 1;
772 	c->main_lebs = c->leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS;
773 	c->main_lebs -= c->log_lebs + c->lpt_lebs + c->orph_lebs;
774 	c->main_first = c->leb_cnt - c->main_lebs;
775 
776 	err = validate_sb(c, sup);
777 out:
778 	return err;
779 }
780 
781 /**
782  * fixup_leb - fixup/unmap an LEB containing free space.
783  * @c: UBIFS file-system description object
784  * @lnum: the LEB number to fix up
785  * @len: number of used bytes in LEB (starting at offset 0)
786  *
787  * This function reads the contents of the given LEB number @lnum, then fixes
788  * it up, so that empty min. I/O units in the end of LEB are actually erased on
789  * flash (rather than being just all-0xff real data). If the LEB is completely
790  * empty, it is simply unmapped.
791  */
792 static int fixup_leb(struct ubifs_info *c, int lnum, int len)
793 {
794 	int err;
795 
796 	ubifs_assert(c, len >= 0);
797 	ubifs_assert(c, len % c->min_io_size == 0);
798 	ubifs_assert(c, len < c->leb_size);
799 
800 	if (len == 0) {
801 		dbg_mnt("unmap empty LEB %d", lnum);
802 		return ubifs_leb_unmap(c, lnum);
803 	}
804 
805 	dbg_mnt("fixup LEB %d, data len %d", lnum, len);
806 	err = ubifs_leb_read(c, lnum, c->sbuf, 0, len, 1);
807 	if (err)
808 		return err;
809 
810 	return ubifs_leb_change(c, lnum, c->sbuf, len);
811 }
812 
813 /**
814  * fixup_free_space - find & remap all LEBs containing free space.
815  * @c: UBIFS file-system description object
816  *
817  * This function walks through all LEBs in the filesystem and fiexes up those
818  * containing free/empty space.
819  */
820 static int fixup_free_space(struct ubifs_info *c)
821 {
822 	int lnum, err = 0;
823 	struct ubifs_lprops *lprops;
824 
825 	ubifs_get_lprops(c);
826 
827 	/* Fixup LEBs in the master area */
828 	for (lnum = UBIFS_MST_LNUM; lnum < UBIFS_LOG_LNUM; lnum++) {
829 		err = fixup_leb(c, lnum, c->mst_offs + c->mst_node_alsz);
830 		if (err)
831 			goto out;
832 	}
833 
834 	/* Unmap unused log LEBs */
835 	lnum = ubifs_next_log_lnum(c, c->lhead_lnum);
836 	while (lnum != c->ltail_lnum) {
837 		err = fixup_leb(c, lnum, 0);
838 		if (err)
839 			goto out;
840 		lnum = ubifs_next_log_lnum(c, lnum);
841 	}
842 
843 	/*
844 	 * Fixup the log head which contains the only a CS node at the
845 	 * beginning.
846 	 */
847 	err = fixup_leb(c, c->lhead_lnum,
848 			ALIGN(UBIFS_CS_NODE_SZ, c->min_io_size));
849 	if (err)
850 		goto out;
851 
852 	/* Fixup LEBs in the LPT area */
853 	for (lnum = c->lpt_first; lnum <= c->lpt_last; lnum++) {
854 		int free = c->ltab[lnum - c->lpt_first].free;
855 
856 		if (free > 0) {
857 			err = fixup_leb(c, lnum, c->leb_size - free);
858 			if (err)
859 				goto out;
860 		}
861 	}
862 
863 	/* Unmap LEBs in the orphans area */
864 	for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
865 		err = fixup_leb(c, lnum, 0);
866 		if (err)
867 			goto out;
868 	}
869 
870 	/* Fixup LEBs in the main area */
871 	for (lnum = c->main_first; lnum < c->leb_cnt; lnum++) {
872 		lprops = ubifs_lpt_lookup(c, lnum);
873 		if (IS_ERR(lprops)) {
874 			err = PTR_ERR(lprops);
875 			goto out;
876 		}
877 
878 		if (lprops->free > 0) {
879 			err = fixup_leb(c, lnum, c->leb_size - lprops->free);
880 			if (err)
881 				goto out;
882 		}
883 	}
884 
885 out:
886 	ubifs_release_lprops(c);
887 	return err;
888 }
889 
890 /**
891  * ubifs_fixup_free_space - find & fix all LEBs with free space.
892  * @c: UBIFS file-system description object
893  *
894  * This function fixes up LEBs containing free space on first mount, if the
895  * appropriate flag was set when the FS was created. Each LEB with one or more
896  * empty min. I/O unit (i.e. free-space-count > 0) is re-written, to make sure
897  * the free space is actually erased. E.g., this is necessary for some NAND
898  * chips, since the free space may have been programmed like real "0xff" data
899  * (generating a non-0xff ECC), causing future writes to the not-really-erased
900  * NAND pages to behave badly. After the space is fixed up, the superblock flag
901  * is cleared, so that this is skipped for all future mounts.
902  */
903 int ubifs_fixup_free_space(struct ubifs_info *c)
904 {
905 	int err;
906 	struct ubifs_sb_node *sup = c->sup_node;
907 
908 	ubifs_assert(c, c->space_fixup);
909 	ubifs_assert(c, !c->ro_mount);
910 
911 	ubifs_msg(c, "start fixing up free space");
912 
913 	err = fixup_free_space(c);
914 	if (err)
915 		return err;
916 
917 	/* Free-space fixup is no longer required */
918 	c->space_fixup = 0;
919 	sup->flags &= cpu_to_le32(~UBIFS_FLG_SPACE_FIXUP);
920 
921 	c->superblock_need_write = 1;
922 
923 	ubifs_msg(c, "free space fixup complete");
924 	return err;
925 }
926 
927 int ubifs_enable_encryption(struct ubifs_info *c)
928 {
929 	int err;
930 	struct ubifs_sb_node *sup = c->sup_node;
931 
932 	if (!IS_ENABLED(CONFIG_FS_ENCRYPTION))
933 		return -EOPNOTSUPP;
934 
935 	if (c->encrypted)
936 		return 0;
937 
938 	if (c->ro_mount || c->ro_media)
939 		return -EROFS;
940 
941 	if (c->fmt_version < 5) {
942 		ubifs_err(c, "on-flash format version 5 is needed for encryption");
943 		return -EINVAL;
944 	}
945 
946 	sup->flags |= cpu_to_le32(UBIFS_FLG_ENCRYPTION);
947 
948 	err = ubifs_write_sb_node(c, sup);
949 	if (!err)
950 		c->encrypted = 1;
951 
952 	return err;
953 }
954