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TOMOYO Linux Cross Reference
Linux/fs/ubifs/sb.c

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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 
 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 = 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_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 }
956 

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