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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