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2b27bdcc | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1e51764a AB |
2 | /* |
3 | * This file is part of UBIFS. | |
4 | * | |
5 | * Copyright (C) 2006-2008 Nokia Corporation. | |
6 | * | |
1e51764a AB |
7 | * Authors: Artem Bityutskiy (Битюцкий Артём) |
8 | * Adrian Hunter | |
9 | */ | |
10 | ||
11 | /* This file implements reading and writing the master node */ | |
12 | ||
13 | #include "ubifs.h" | |
14 | ||
625700cc SH |
15 | /** |
16 | * ubifs_compare_master_node - compare two UBIFS master nodes | |
17 | * @c: UBIFS file-system description object | |
18 | * @m1: the first node | |
19 | * @m2: the second node | |
20 | * | |
21 | * This function compares two UBIFS master nodes. Returns 0 if they are equal | |
22 | * and nonzero if not. | |
23 | */ | |
24 | int ubifs_compare_master_node(struct ubifs_info *c, void *m1, void *m2) | |
25 | { | |
26 | int ret; | |
27 | int behind; | |
28 | int hmac_offs = offsetof(struct ubifs_mst_node, hmac); | |
29 | ||
30 | /* | |
31 | * Do not compare the common node header since the sequence number and | |
32 | * hence the CRC are different. | |
33 | */ | |
34 | ret = memcmp(m1 + UBIFS_CH_SZ, m2 + UBIFS_CH_SZ, | |
35 | hmac_offs - UBIFS_CH_SZ); | |
36 | if (ret) | |
37 | return ret; | |
38 | ||
39 | /* | |
07c32de4 | 40 | * Do not compare the embedded HMAC as well which also must be different |
625700cc SH |
41 | * due to the different common node header. |
42 | */ | |
43 | behind = hmac_offs + UBIFS_MAX_HMAC_LEN; | |
44 | ||
45 | if (UBIFS_MST_NODE_SZ > behind) | |
46 | return memcmp(m1 + behind, m2 + behind, UBIFS_MST_NODE_SZ - behind); | |
47 | ||
48 | return 0; | |
49 | } | |
50 | ||
817aa094 SH |
51 | /* mst_node_check_hash - Check hash of a master node |
52 | * @c: UBIFS file-system description object | |
53 | * @mst: The master node | |
54 | * @expected: The expected hash of the master node | |
55 | * | |
56 | * This checks the hash of a master node against a given expected hash. | |
57 | * Note that we have two master nodes on a UBIFS image which have different | |
58 | * sequence numbers and consequently different CRCs. To be able to match | |
59 | * both master nodes we exclude the common node header containing the sequence | |
60 | * number and CRC from the hash. | |
61 | * | |
62 | * Returns 0 if the hashes are equal, a negative error code otherwise. | |
63 | */ | |
64 | static int mst_node_check_hash(const struct ubifs_info *c, | |
65 | const struct ubifs_mst_node *mst, | |
66 | const u8 *expected) | |
67 | { | |
68 | u8 calc[UBIFS_MAX_HASH_LEN]; | |
69 | const void *node = mst; | |
70 | ||
f80df385 EB |
71 | crypto_shash_tfm_digest(c->hash_tfm, node + sizeof(struct ubifs_ch), |
72 | UBIFS_MST_NODE_SZ - sizeof(struct ubifs_ch), | |
73 | calc); | |
817aa094 SH |
74 | |
75 | if (ubifs_check_hash(c, expected, calc)) | |
76 | return -EPERM; | |
77 | ||
78 | return 0; | |
79 | } | |
80 | ||
1e51764a AB |
81 | /** |
82 | * scan_for_master - search the valid master node. | |
83 | * @c: UBIFS file-system description object | |
84 | * | |
85 | * This function scans the master node LEBs and search for the latest master | |
0dcd18e4 AB |
86 | * node. Returns zero in case of success, %-EUCLEAN if there master area is |
87 | * corrupted and requires recovery, and a negative error code in case of | |
1e51764a AB |
88 | * failure. |
89 | */ | |
90 | static int scan_for_master(struct ubifs_info *c) | |
91 | { | |
92 | struct ubifs_scan_leb *sleb; | |
93 | struct ubifs_scan_node *snod; | |
625700cc | 94 | int lnum, offs = 0, nodes_cnt, err; |
1e51764a AB |
95 | |
96 | lnum = UBIFS_MST_LNUM; | |
97 | ||
348709ba | 98 | sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1); |
1e51764a AB |
99 | if (IS_ERR(sleb)) |
100 | return PTR_ERR(sleb); | |
101 | nodes_cnt = sleb->nodes_cnt; | |
102 | if (nodes_cnt > 0) { | |
103 | snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node, | |
104 | list); | |
105 | if (snod->type != UBIFS_MST_NODE) | |
0dcd18e4 | 106 | goto out_dump; |
1e51764a AB |
107 | memcpy(c->mst_node, snod->node, snod->len); |
108 | offs = snod->offs; | |
109 | } | |
110 | ubifs_scan_destroy(sleb); | |
111 | ||
112 | lnum += 1; | |
113 | ||
348709ba | 114 | sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1); |
1e51764a AB |
115 | if (IS_ERR(sleb)) |
116 | return PTR_ERR(sleb); | |
117 | if (sleb->nodes_cnt != nodes_cnt) | |
118 | goto out; | |
119 | if (!sleb->nodes_cnt) | |
120 | goto out; | |
121 | snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node, list); | |
122 | if (snod->type != UBIFS_MST_NODE) | |
0dcd18e4 | 123 | goto out_dump; |
1e51764a AB |
124 | if (snod->offs != offs) |
125 | goto out; | |
625700cc | 126 | if (ubifs_compare_master_node(c, c->mst_node, snod->node)) |
1e51764a | 127 | goto out; |
625700cc | 128 | |
1e51764a AB |
129 | c->mst_offs = offs; |
130 | ubifs_scan_destroy(sleb); | |
625700cc SH |
131 | |
132 | if (!ubifs_authenticated(c)) | |
133 | return 0; | |
134 | ||
817aa094 SH |
135 | if (ubifs_hmac_zero(c, c->mst_node->hmac)) { |
136 | err = mst_node_check_hash(c, c->mst_node, | |
137 | c->sup_node->hash_mst); | |
138 | if (err) | |
139 | ubifs_err(c, "Failed to verify master node hash"); | |
140 | } else { | |
141 | err = ubifs_node_verify_hmac(c, c->mst_node, | |
142 | sizeof(struct ubifs_mst_node), | |
143 | offsetof(struct ubifs_mst_node, hmac)); | |
144 | if (err) | |
145 | ubifs_err(c, "Failed to verify master node HMAC"); | |
625700cc SH |
146 | } |
147 | ||
817aa094 SH |
148 | if (err) |
149 | return -EPERM; | |
150 | ||
1e51764a AB |
151 | return 0; |
152 | ||
153 | out: | |
154 | ubifs_scan_destroy(sleb); | |
0dcd18e4 AB |
155 | return -EUCLEAN; |
156 | ||
157 | out_dump: | |
235c362b | 158 | ubifs_err(c, "unexpected node type %d master LEB %d:%d", |
0dcd18e4 AB |
159 | snod->type, lnum, snod->offs); |
160 | ubifs_scan_destroy(sleb); | |
1e51764a AB |
161 | return -EINVAL; |
162 | } | |
163 | ||
164 | /** | |
165 | * validate_master - validate master node. | |
166 | * @c: UBIFS file-system description object | |
167 | * | |
168 | * This function validates data which was read from master node. Returns zero | |
169 | * if the data is all right and %-EINVAL if not. | |
170 | */ | |
171 | static int validate_master(const struct ubifs_info *c) | |
172 | { | |
173 | long long main_sz; | |
174 | int err; | |
175 | ||
176 | if (c->max_sqnum >= SQNUM_WATERMARK) { | |
177 | err = 1; | |
178 | goto out; | |
179 | } | |
180 | ||
181 | if (c->cmt_no >= c->max_sqnum) { | |
182 | err = 2; | |
183 | goto out; | |
184 | } | |
185 | ||
186 | if (c->highest_inum >= INUM_WATERMARK) { | |
187 | err = 3; | |
188 | goto out; | |
189 | } | |
190 | ||
191 | if (c->lhead_lnum < UBIFS_LOG_LNUM || | |
192 | c->lhead_lnum >= UBIFS_LOG_LNUM + c->log_lebs || | |
193 | c->lhead_offs < 0 || c->lhead_offs >= c->leb_size || | |
194 | c->lhead_offs & (c->min_io_size - 1)) { | |
195 | err = 4; | |
196 | goto out; | |
197 | } | |
198 | ||
199 | if (c->zroot.lnum >= c->leb_cnt || c->zroot.lnum < c->main_first || | |
200 | c->zroot.offs >= c->leb_size || c->zroot.offs & 7) { | |
201 | err = 5; | |
202 | goto out; | |
203 | } | |
204 | ||
205 | if (c->zroot.len < c->ranges[UBIFS_IDX_NODE].min_len || | |
206 | c->zroot.len > c->ranges[UBIFS_IDX_NODE].max_len) { | |
207 | err = 6; | |
208 | goto out; | |
209 | } | |
210 | ||
211 | if (c->gc_lnum >= c->leb_cnt || c->gc_lnum < c->main_first) { | |
212 | err = 7; | |
213 | goto out; | |
214 | } | |
215 | ||
216 | if (c->ihead_lnum >= c->leb_cnt || c->ihead_lnum < c->main_first || | |
217 | c->ihead_offs % c->min_io_size || c->ihead_offs < 0 || | |
218 | c->ihead_offs > c->leb_size || c->ihead_offs & 7) { | |
219 | err = 8; | |
220 | goto out; | |
221 | } | |
222 | ||
223 | main_sz = (long long)c->main_lebs * c->leb_size; | |
b137545c | 224 | if (c->bi.old_idx_sz & 7 || c->bi.old_idx_sz >= main_sz) { |
1e51764a AB |
225 | err = 9; |
226 | goto out; | |
227 | } | |
228 | ||
229 | if (c->lpt_lnum < c->lpt_first || c->lpt_lnum > c->lpt_last || | |
230 | c->lpt_offs < 0 || c->lpt_offs + c->nnode_sz > c->leb_size) { | |
231 | err = 10; | |
232 | goto out; | |
233 | } | |
234 | ||
235 | if (c->nhead_lnum < c->lpt_first || c->nhead_lnum > c->lpt_last || | |
236 | c->nhead_offs < 0 || c->nhead_offs % c->min_io_size || | |
237 | c->nhead_offs > c->leb_size) { | |
238 | err = 11; | |
239 | goto out; | |
240 | } | |
241 | ||
242 | if (c->ltab_lnum < c->lpt_first || c->ltab_lnum > c->lpt_last || | |
243 | c->ltab_offs < 0 || | |
244 | c->ltab_offs + c->ltab_sz > c->leb_size) { | |
245 | err = 12; | |
246 | goto out; | |
247 | } | |
248 | ||
249 | if (c->big_lpt && (c->lsave_lnum < c->lpt_first || | |
250 | c->lsave_lnum > c->lpt_last || c->lsave_offs < 0 || | |
251 | c->lsave_offs + c->lsave_sz > c->leb_size)) { | |
252 | err = 13; | |
253 | goto out; | |
254 | } | |
255 | ||
256 | if (c->lscan_lnum < c->main_first || c->lscan_lnum >= c->leb_cnt) { | |
257 | err = 14; | |
258 | goto out; | |
259 | } | |
260 | ||
261 | if (c->lst.empty_lebs < 0 || c->lst.empty_lebs > c->main_lebs - 2) { | |
262 | err = 15; | |
263 | goto out; | |
264 | } | |
265 | ||
266 | if (c->lst.idx_lebs < 0 || c->lst.idx_lebs > c->main_lebs - 1) { | |
267 | err = 16; | |
268 | goto out; | |
269 | } | |
270 | ||
271 | if (c->lst.total_free < 0 || c->lst.total_free > main_sz || | |
272 | c->lst.total_free & 7) { | |
273 | err = 17; | |
274 | goto out; | |
275 | } | |
276 | ||
277 | if (c->lst.total_dirty < 0 || (c->lst.total_dirty & 7)) { | |
278 | err = 18; | |
279 | goto out; | |
280 | } | |
281 | ||
282 | if (c->lst.total_used < 0 || (c->lst.total_used & 7)) { | |
283 | err = 19; | |
284 | goto out; | |
285 | } | |
286 | ||
287 | if (c->lst.total_free + c->lst.total_dirty + | |
288 | c->lst.total_used > main_sz) { | |
289 | err = 20; | |
290 | goto out; | |
291 | } | |
292 | ||
293 | if (c->lst.total_dead + c->lst.total_dark + | |
b137545c | 294 | c->lst.total_used + c->bi.old_idx_sz > main_sz) { |
1e51764a AB |
295 | err = 21; |
296 | goto out; | |
297 | } | |
298 | ||
299 | if (c->lst.total_dead < 0 || | |
300 | c->lst.total_dead > c->lst.total_free + c->lst.total_dirty || | |
301 | c->lst.total_dead & 7) { | |
302 | err = 22; | |
303 | goto out; | |
304 | } | |
305 | ||
306 | if (c->lst.total_dark < 0 || | |
307 | c->lst.total_dark > c->lst.total_free + c->lst.total_dirty || | |
308 | c->lst.total_dark & 7) { | |
309 | err = 23; | |
310 | goto out; | |
311 | } | |
312 | ||
313 | return 0; | |
314 | ||
315 | out: | |
235c362b | 316 | ubifs_err(c, "bad master node at offset %d error %d", c->mst_offs, err); |
a33e30a0 | 317 | ubifs_dump_node(c, c->mst_node, c->mst_node_alsz); |
1e51764a AB |
318 | return -EINVAL; |
319 | } | |
320 | ||
321 | /** | |
322 | * ubifs_read_master - read master node. | |
323 | * @c: UBIFS file-system description object | |
324 | * | |
325 | * This function finds and reads the master node during file-system mount. If | |
326 | * the flash is empty, it creates default master node as well. Returns zero in | |
327 | * case of success and a negative error code in case of failure. | |
328 | */ | |
329 | int ubifs_read_master(struct ubifs_info *c) | |
330 | { | |
331 | int err, old_leb_cnt; | |
332 | ||
333 | c->mst_node = kzalloc(c->mst_node_alsz, GFP_KERNEL); | |
334 | if (!c->mst_node) | |
335 | return -ENOMEM; | |
336 | ||
337 | err = scan_for_master(c); | |
338 | if (err) { | |
0dcd18e4 AB |
339 | if (err == -EUCLEAN) |
340 | err = ubifs_recover_master_node(c); | |
1e51764a AB |
341 | if (err) |
342 | /* | |
343 | * Note, we do not free 'c->mst_node' here because the | |
344 | * unmount routine will take care of this. | |
345 | */ | |
346 | return err; | |
347 | } | |
348 | ||
349 | /* Make sure that the recovery flag is clear */ | |
350 | c->mst_node->flags &= cpu_to_le32(~UBIFS_MST_RCVRY); | |
351 | ||
352 | c->max_sqnum = le64_to_cpu(c->mst_node->ch.sqnum); | |
353 | c->highest_inum = le64_to_cpu(c->mst_node->highest_inum); | |
354 | c->cmt_no = le64_to_cpu(c->mst_node->cmt_no); | |
355 | c->zroot.lnum = le32_to_cpu(c->mst_node->root_lnum); | |
356 | c->zroot.offs = le32_to_cpu(c->mst_node->root_offs); | |
357 | c->zroot.len = le32_to_cpu(c->mst_node->root_len); | |
358 | c->lhead_lnum = le32_to_cpu(c->mst_node->log_lnum); | |
359 | c->gc_lnum = le32_to_cpu(c->mst_node->gc_lnum); | |
360 | c->ihead_lnum = le32_to_cpu(c->mst_node->ihead_lnum); | |
361 | c->ihead_offs = le32_to_cpu(c->mst_node->ihead_offs); | |
b137545c | 362 | c->bi.old_idx_sz = le64_to_cpu(c->mst_node->index_size); |
1e51764a AB |
363 | c->lpt_lnum = le32_to_cpu(c->mst_node->lpt_lnum); |
364 | c->lpt_offs = le32_to_cpu(c->mst_node->lpt_offs); | |
365 | c->nhead_lnum = le32_to_cpu(c->mst_node->nhead_lnum); | |
366 | c->nhead_offs = le32_to_cpu(c->mst_node->nhead_offs); | |
367 | c->ltab_lnum = le32_to_cpu(c->mst_node->ltab_lnum); | |
368 | c->ltab_offs = le32_to_cpu(c->mst_node->ltab_offs); | |
369 | c->lsave_lnum = le32_to_cpu(c->mst_node->lsave_lnum); | |
370 | c->lsave_offs = le32_to_cpu(c->mst_node->lsave_offs); | |
371 | c->lscan_lnum = le32_to_cpu(c->mst_node->lscan_lnum); | |
372 | c->lst.empty_lebs = le32_to_cpu(c->mst_node->empty_lebs); | |
373 | c->lst.idx_lebs = le32_to_cpu(c->mst_node->idx_lebs); | |
374 | old_leb_cnt = le32_to_cpu(c->mst_node->leb_cnt); | |
375 | c->lst.total_free = le64_to_cpu(c->mst_node->total_free); | |
376 | c->lst.total_dirty = le64_to_cpu(c->mst_node->total_dirty); | |
377 | c->lst.total_used = le64_to_cpu(c->mst_node->total_used); | |
378 | c->lst.total_dead = le64_to_cpu(c->mst_node->total_dead); | |
379 | c->lst.total_dark = le64_to_cpu(c->mst_node->total_dark); | |
380 | ||
16a26b20 SH |
381 | ubifs_copy_hash(c, c->mst_node->hash_root_idx, c->zroot.hash); |
382 | ||
b137545c | 383 | c->calc_idx_sz = c->bi.old_idx_sz; |
1e51764a AB |
384 | |
385 | if (c->mst_node->flags & cpu_to_le32(UBIFS_MST_NO_ORPHS)) | |
386 | c->no_orphs = 1; | |
387 | ||
388 | if (old_leb_cnt != c->leb_cnt) { | |
389 | /* The file system has been resized */ | |
390 | int growth = c->leb_cnt - old_leb_cnt; | |
391 | ||
392 | if (c->leb_cnt < old_leb_cnt || | |
393 | c->leb_cnt < UBIFS_MIN_LEB_CNT) { | |
235c362b | 394 | ubifs_err(c, "bad leb_cnt on master node"); |
a33e30a0 | 395 | ubifs_dump_node(c, c->mst_node, c->mst_node_alsz); |
1e51764a AB |
396 | return -EINVAL; |
397 | } | |
398 | ||
399 | dbg_mnt("Auto resizing (master) from %d LEBs to %d LEBs", | |
400 | old_leb_cnt, c->leb_cnt); | |
401 | c->lst.empty_lebs += growth; | |
402 | c->lst.total_free += growth * (long long)c->leb_size; | |
403 | c->lst.total_dark += growth * (long long)c->dark_wm; | |
404 | ||
405 | /* | |
406 | * Reflect changes back onto the master node. N.B. the master | |
407 | * node gets written immediately whenever mounting (or | |
408 | * remounting) in read-write mode, so we do not need to write it | |
409 | * here. | |
410 | */ | |
411 | c->mst_node->leb_cnt = cpu_to_le32(c->leb_cnt); | |
412 | c->mst_node->empty_lebs = cpu_to_le32(c->lst.empty_lebs); | |
413 | c->mst_node->total_free = cpu_to_le64(c->lst.total_free); | |
414 | c->mst_node->total_dark = cpu_to_le64(c->lst.total_dark); | |
415 | } | |
416 | ||
417 | err = validate_master(c); | |
418 | if (err) | |
419 | return err; | |
420 | ||
421 | err = dbg_old_index_check_init(c, &c->zroot); | |
422 | ||
423 | return err; | |
424 | } | |
425 | ||
426 | /** | |
427 | * ubifs_write_master - write master node. | |
428 | * @c: UBIFS file-system description object | |
429 | * | |
07e19dff AB |
430 | * This function writes the master node. Returns zero in case of success and a |
431 | * negative error code in case of failure. The master node is written twice to | |
432 | * enable recovery. | |
1e51764a AB |
433 | */ |
434 | int ubifs_write_master(struct ubifs_info *c) | |
435 | { | |
436 | int err, lnum, offs, len; | |
437 | ||
6eb61d58 | 438 | ubifs_assert(c, !c->ro_media && !c->ro_mount); |
2680d722 | 439 | if (c->ro_error) |
a2b9df3f | 440 | return -EROFS; |
1e51764a AB |
441 | |
442 | lnum = UBIFS_MST_LNUM; | |
443 | offs = c->mst_offs + c->mst_node_alsz; | |
444 | len = UBIFS_MST_NODE_SZ; | |
445 | ||
446 | if (offs + UBIFS_MST_NODE_SZ > c->leb_size) { | |
447 | err = ubifs_leb_unmap(c, lnum); | |
448 | if (err) | |
449 | return err; | |
450 | offs = 0; | |
451 | } | |
452 | ||
453 | c->mst_offs = offs; | |
454 | c->mst_node->highest_inum = cpu_to_le64(c->highest_inum); | |
455 | ||
16a26b20 | 456 | ubifs_copy_hash(c, c->zroot.hash, c->mst_node->hash_root_idx); |
625700cc SH |
457 | err = ubifs_write_node_hmac(c, c->mst_node, len, lnum, offs, |
458 | offsetof(struct ubifs_mst_node, hmac)); | |
1e51764a AB |
459 | if (err) |
460 | return err; | |
461 | ||
462 | lnum += 1; | |
463 | ||
464 | if (offs == 0) { | |
465 | err = ubifs_leb_unmap(c, lnum); | |
466 | if (err) | |
467 | return err; | |
468 | } | |
625700cc SH |
469 | err = ubifs_write_node_hmac(c, c->mst_node, len, lnum, offs, |
470 | offsetof(struct ubifs_mst_node, hmac)); | |
1e51764a AB |
471 | |
472 | return err; | |
473 | } |