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 extended attributes support. |
13 | * |
14 | * Extended attributes are implemented as regular inodes with attached data, |
15 | * which limits extended attribute size to UBIFS block size (4KiB). Names of |
16 | * extended attributes are described by extended attribute entries (xentries), |
17 | * which are almost identical to directory entries, but have different key type. |
18 | * |
19 | * In other words, the situation with extended attributes is very similar to |
20 | * directories. Indeed, any inode (but of course not xattr inodes) may have a |
21 | * number of associated xentries, just like directory inodes have associated |
22 | * directory entries. Extended attribute entries store the name of the extended |
23 | * attribute, the host inode number, and the extended attribute inode number. |
24 | * Similarly, direntries store the name, the parent and the target inode |
25 | * numbers. Thus, most of the common UBIFS mechanisms may be re-used for |
26 | * extended attributes. |
27 | * |
28 | * The number of extended attributes is not limited, but there is Linux |
29 | * limitation on the maximum possible size of the list of all extended |
30 | * attributes associated with an inode (%XATTR_LIST_MAX), so UBIFS makes sure |
31 | * the sum of all extended attribute names of the inode does not exceed that |
32 | * limit. |
33 | * |
34 | * Extended attributes are synchronous, which means they are written to the |
35 | * flash media synchronously and there is no write-back for extended attribute |
36 | * inodes. The extended attribute values are not stored in compressed form on |
37 | * the media. |
38 | * |
39 | * Since extended attributes are represented by regular inodes, they are cached |
40 | * in the VFS inode cache. The xentries are cached in the LNC cache (see |
41 | * tnc.c). |
42 | * |
43 | * ACL support is not implemented. |
44 | */ |
45 | |
46 | #include "ubifs.h" |
47 | #include <linux/fs.h> |
48 | #include <linux/slab.h> |
49 | #include <linux/xattr.h> |
50 | |
51 | /* |
52 | * Extended attribute type constants. |
53 | * |
54 | * USER_XATTR: user extended attribute ("user.*") |
55 | * TRUSTED_XATTR: trusted extended attribute ("trusted.*) |
56 | * SECURITY_XATTR: security extended attribute ("security.*") |
57 | */ |
58 | enum { |
59 | USER_XATTR, |
60 | TRUSTED_XATTR, |
61 | SECURITY_XATTR, |
62 | }; |
63 | |
64 | static const struct inode_operations empty_iops; |
65 | static const struct file_operations empty_fops; |
66 | |
67 | /** |
68 | * create_xattr - create an extended attribute. |
69 | * @c: UBIFS file-system description object |
70 | * @host: host inode |
71 | * @nm: extended attribute name |
72 | * @value: extended attribute value |
73 | * @size: size of extended attribute value |
74 | * |
75 | * This is a helper function which creates an extended attribute of name @nm |
76 | * and value @value for inode @host. The host inode is also updated on flash |
77 | * because the ctime and extended attribute accounting data changes. This |
78 | * function returns zero in case of success and a negative error code in case |
79 | * of failure. |
80 | */ |
81 | static int create_xattr(struct ubifs_info *c, struct inode *host, |
82 | const struct fscrypt_name *nm, const void *value, int size) |
83 | { |
84 | int err, names_len; |
85 | struct inode *inode; |
86 | struct ubifs_inode *ui, *host_ui = ubifs_inode(inode: host); |
87 | struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1, |
88 | .new_ino_d = ALIGN(size, 8), .dirtied_ino = 1, |
89 | .dirtied_ino_d = ALIGN(host_ui->data_len, 8) }; |
90 | |
91 | if (host_ui->xattr_cnt >= ubifs_xattr_max_cnt(c)) { |
92 | ubifs_err(c, fmt: "inode %lu already has too many xattrs (%d), cannot create more" , |
93 | host->i_ino, host_ui->xattr_cnt); |
94 | return -ENOSPC; |
95 | } |
96 | /* |
97 | * Linux limits the maximum size of the extended attribute names list |
98 | * to %XATTR_LIST_MAX. This means we should not allow creating more |
99 | * extended attributes if the name list becomes larger. This limitation |
100 | * is artificial for UBIFS, though. |
101 | */ |
102 | names_len = host_ui->xattr_names + host_ui->xattr_cnt + fname_len(nm) + 1; |
103 | if (names_len > XATTR_LIST_MAX) { |
104 | ubifs_err(c, fmt: "cannot add one more xattr name to inode %lu, total names length would become %d, max. is %d" , |
105 | host->i_ino, names_len, XATTR_LIST_MAX); |
106 | return -ENOSPC; |
107 | } |
108 | |
109 | err = ubifs_budget_space(c, req: &req); |
110 | if (err) |
111 | return err; |
112 | |
113 | inode = ubifs_new_inode(c, dir: host, S_IFREG | S_IRWXUGO, is_xattr: true); |
114 | if (IS_ERR(ptr: inode)) { |
115 | err = PTR_ERR(ptr: inode); |
116 | goto out_budg; |
117 | } |
118 | |
119 | /* Re-define all operations to be "nothing" */ |
120 | inode->i_mapping->a_ops = &empty_aops; |
121 | inode->i_op = &empty_iops; |
122 | inode->i_fop = &empty_fops; |
123 | |
124 | inode->i_flags |= S_SYNC | S_NOATIME | S_NOCMTIME; |
125 | ui = ubifs_inode(inode); |
126 | ui->xattr = 1; |
127 | ui->flags |= UBIFS_XATTR_FL; |
128 | ui->data = kmemdup(p: value, size, GFP_NOFS); |
129 | if (!ui->data) { |
130 | err = -ENOMEM; |
131 | goto out_free; |
132 | } |
133 | inode->i_size = ui->ui_size = size; |
134 | ui->data_len = size; |
135 | |
136 | mutex_lock(&host_ui->ui_mutex); |
137 | inode_set_ctime_current(inode: host); |
138 | host_ui->xattr_cnt += 1; |
139 | host_ui->xattr_size += CALC_DENT_SIZE(fname_len(nm)); |
140 | host_ui->xattr_size += CALC_XATTR_BYTES(size); |
141 | host_ui->xattr_names += fname_len(nm); |
142 | |
143 | /* |
144 | * We handle UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT here because we |
145 | * have to set the UBIFS_CRYPT_FL flag on the host inode. |
146 | * To avoid multiple updates of the same inode in the same operation, |
147 | * let's do it here. |
148 | */ |
149 | if (strcmp(fname_name(nm), UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT) == 0) |
150 | host_ui->flags |= UBIFS_CRYPT_FL; |
151 | |
152 | err = ubifs_jnl_update(c, dir: host, nm, inode, deletion: 0, xent: 1); |
153 | if (err) |
154 | goto out_cancel; |
155 | ubifs_set_inode_flags(inode: host); |
156 | mutex_unlock(lock: &host_ui->ui_mutex); |
157 | |
158 | ubifs_release_budget(c, req: &req); |
159 | insert_inode_hash(inode); |
160 | iput(inode); |
161 | return 0; |
162 | |
163 | out_cancel: |
164 | host_ui->xattr_cnt -= 1; |
165 | host_ui->xattr_size -= CALC_DENT_SIZE(fname_len(nm)); |
166 | host_ui->xattr_size -= CALC_XATTR_BYTES(size); |
167 | host_ui->xattr_names -= fname_len(nm); |
168 | host_ui->flags &= ~UBIFS_CRYPT_FL; |
169 | mutex_unlock(lock: &host_ui->ui_mutex); |
170 | out_free: |
171 | make_bad_inode(inode); |
172 | iput(inode); |
173 | out_budg: |
174 | ubifs_release_budget(c, req: &req); |
175 | return err; |
176 | } |
177 | |
178 | /** |
179 | * change_xattr - change an extended attribute. |
180 | * @c: UBIFS file-system description object |
181 | * @host: host inode |
182 | * @inode: extended attribute inode |
183 | * @value: extended attribute value |
184 | * @size: size of extended attribute value |
185 | * |
186 | * This helper function changes the value of extended attribute @inode with new |
187 | * data from @value. Returns zero in case of success and a negative error code |
188 | * in case of failure. |
189 | */ |
190 | static int change_xattr(struct ubifs_info *c, struct inode *host, |
191 | struct inode *inode, const void *value, int size) |
192 | { |
193 | int err; |
194 | struct ubifs_inode *host_ui = ubifs_inode(inode: host); |
195 | struct ubifs_inode *ui = ubifs_inode(inode); |
196 | void *buf = NULL; |
197 | int old_size; |
198 | struct ubifs_budget_req req = { .dirtied_ino = 2, |
199 | .dirtied_ino_d = ALIGN(size, 8) + ALIGN(host_ui->data_len, 8) }; |
200 | |
201 | ubifs_assert(c, ui->data_len == inode->i_size); |
202 | err = ubifs_budget_space(c, req: &req); |
203 | if (err) |
204 | return err; |
205 | |
206 | buf = kmemdup(p: value, size, GFP_NOFS); |
207 | if (!buf) { |
208 | err = -ENOMEM; |
209 | goto out_free; |
210 | } |
211 | kfree(objp: ui->data); |
212 | ui->data = buf; |
213 | inode->i_size = ui->ui_size = size; |
214 | old_size = ui->data_len; |
215 | ui->data_len = size; |
216 | |
217 | mutex_lock(&host_ui->ui_mutex); |
218 | inode_set_ctime_current(inode: host); |
219 | host_ui->xattr_size -= CALC_XATTR_BYTES(old_size); |
220 | host_ui->xattr_size += CALC_XATTR_BYTES(size); |
221 | |
222 | /* |
223 | * It is important to write the host inode after the xattr inode |
224 | * because if the host inode gets synchronized (via 'fsync()'), then |
225 | * the extended attribute inode gets synchronized, because it goes |
226 | * before the host inode in the write-buffer. |
227 | */ |
228 | err = ubifs_jnl_change_xattr(c, inode1: inode, inode2: host); |
229 | if (err) |
230 | goto out_cancel; |
231 | mutex_unlock(lock: &host_ui->ui_mutex); |
232 | |
233 | ubifs_release_budget(c, req: &req); |
234 | return 0; |
235 | |
236 | out_cancel: |
237 | host_ui->xattr_size -= CALC_XATTR_BYTES(size); |
238 | host_ui->xattr_size += CALC_XATTR_BYTES(old_size); |
239 | mutex_unlock(lock: &host_ui->ui_mutex); |
240 | make_bad_inode(inode); |
241 | out_free: |
242 | ubifs_release_budget(c, req: &req); |
243 | return err; |
244 | } |
245 | |
246 | static struct inode *iget_xattr(struct ubifs_info *c, ino_t inum) |
247 | { |
248 | struct inode *inode; |
249 | |
250 | inode = ubifs_iget(sb: c->vfs_sb, inum); |
251 | if (IS_ERR(ptr: inode)) { |
252 | ubifs_err(c, fmt: "dead extended attribute entry, error %d" , |
253 | (int)PTR_ERR(ptr: inode)); |
254 | return inode; |
255 | } |
256 | if (ubifs_inode(inode)->xattr) |
257 | return inode; |
258 | ubifs_err(c, fmt: "corrupt extended attribute entry" ); |
259 | iput(inode); |
260 | return ERR_PTR(error: -EINVAL); |
261 | } |
262 | |
263 | int ubifs_xattr_set(struct inode *host, const char *name, const void *value, |
264 | size_t size, int flags, bool check_lock) |
265 | { |
266 | struct inode *inode; |
267 | struct ubifs_info *c = host->i_sb->s_fs_info; |
268 | struct fscrypt_name nm = { .disk_name = FSTR_INIT((char *)name, strlen(name))}; |
269 | struct ubifs_dent_node *xent; |
270 | union ubifs_key key; |
271 | int err; |
272 | |
273 | if (check_lock) |
274 | ubifs_assert(c, inode_is_locked(host)); |
275 | |
276 | if (size > UBIFS_MAX_INO_DATA) |
277 | return -ERANGE; |
278 | |
279 | if (fname_len(&nm) > UBIFS_MAX_NLEN) |
280 | return -ENAMETOOLONG; |
281 | |
282 | xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS); |
283 | if (!xent) |
284 | return -ENOMEM; |
285 | |
286 | down_write(sem: &ubifs_inode(inode: host)->xattr_sem); |
287 | /* |
288 | * The extended attribute entries are stored in LNC, so multiple |
289 | * look-ups do not involve reading the flash. |
290 | */ |
291 | xent_key_init(c, key: &key, inum: host->i_ino, nm: &nm); |
292 | err = ubifs_tnc_lookup_nm(c, key: &key, node: xent, nm: &nm); |
293 | if (err) { |
294 | if (err != -ENOENT) |
295 | goto out_free; |
296 | |
297 | if (flags & XATTR_REPLACE) |
298 | /* We are asked not to create the xattr */ |
299 | err = -ENODATA; |
300 | else |
301 | err = create_xattr(c, host, nm: &nm, value, size); |
302 | goto out_free; |
303 | } |
304 | |
305 | if (flags & XATTR_CREATE) { |
306 | /* We are asked not to replace the xattr */ |
307 | err = -EEXIST; |
308 | goto out_free; |
309 | } |
310 | |
311 | inode = iget_xattr(c, le64_to_cpu(xent->inum)); |
312 | if (IS_ERR(ptr: inode)) { |
313 | err = PTR_ERR(ptr: inode); |
314 | goto out_free; |
315 | } |
316 | |
317 | err = change_xattr(c, host, inode, value, size); |
318 | iput(inode); |
319 | |
320 | out_free: |
321 | up_write(sem: &ubifs_inode(inode: host)->xattr_sem); |
322 | kfree(objp: xent); |
323 | return err; |
324 | } |
325 | |
326 | ssize_t ubifs_xattr_get(struct inode *host, const char *name, void *buf, |
327 | size_t size) |
328 | { |
329 | struct inode *inode; |
330 | struct ubifs_info *c = host->i_sb->s_fs_info; |
331 | struct fscrypt_name nm = { .disk_name = FSTR_INIT((char *)name, strlen(name))}; |
332 | struct ubifs_inode *ui; |
333 | struct ubifs_dent_node *xent; |
334 | union ubifs_key key; |
335 | int err; |
336 | |
337 | if (fname_len(&nm) > UBIFS_MAX_NLEN) |
338 | return -ENAMETOOLONG; |
339 | |
340 | xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS); |
341 | if (!xent) |
342 | return -ENOMEM; |
343 | |
344 | down_read(sem: &ubifs_inode(inode: host)->xattr_sem); |
345 | xent_key_init(c, key: &key, inum: host->i_ino, nm: &nm); |
346 | err = ubifs_tnc_lookup_nm(c, key: &key, node: xent, nm: &nm); |
347 | if (err) { |
348 | if (err == -ENOENT) |
349 | err = -ENODATA; |
350 | goto out_cleanup; |
351 | } |
352 | |
353 | inode = iget_xattr(c, le64_to_cpu(xent->inum)); |
354 | if (IS_ERR(ptr: inode)) { |
355 | err = PTR_ERR(ptr: inode); |
356 | goto out_cleanup; |
357 | } |
358 | |
359 | ui = ubifs_inode(inode); |
360 | ubifs_assert(c, inode->i_size == ui->data_len); |
361 | ubifs_assert(c, ubifs_inode(host)->xattr_size > ui->data_len); |
362 | |
363 | if (buf) { |
364 | /* If @buf is %NULL we are supposed to return the length */ |
365 | if (ui->data_len > size) { |
366 | err = -ERANGE; |
367 | goto out_iput; |
368 | } |
369 | |
370 | memcpy(buf, ui->data, ui->data_len); |
371 | } |
372 | err = ui->data_len; |
373 | |
374 | out_iput: |
375 | iput(inode); |
376 | out_cleanup: |
377 | up_read(sem: &ubifs_inode(inode: host)->xattr_sem); |
378 | kfree(objp: xent); |
379 | return err; |
380 | } |
381 | |
382 | static bool xattr_visible(const char *name) |
383 | { |
384 | /* File encryption related xattrs are for internal use only */ |
385 | if (strcmp(name, UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT) == 0) |
386 | return false; |
387 | |
388 | /* Show trusted namespace only for "power" users */ |
389 | if (strncmp(name, XATTR_TRUSTED_PREFIX, |
390 | XATTR_TRUSTED_PREFIX_LEN) == 0 && !capable(CAP_SYS_ADMIN)) |
391 | return false; |
392 | |
393 | return true; |
394 | } |
395 | |
396 | ssize_t ubifs_listxattr(struct dentry *dentry, char *buffer, size_t size) |
397 | { |
398 | union ubifs_key key; |
399 | struct inode *host = d_inode(dentry); |
400 | struct ubifs_info *c = host->i_sb->s_fs_info; |
401 | struct ubifs_inode *host_ui = ubifs_inode(inode: host); |
402 | struct ubifs_dent_node *xent, *pxent = NULL; |
403 | int err, len, written = 0; |
404 | struct fscrypt_name nm = {0}; |
405 | |
406 | dbg_gen("ino %lu ('%pd'), buffer size %zd" , host->i_ino, |
407 | dentry, size); |
408 | |
409 | down_read(sem: &host_ui->xattr_sem); |
410 | len = host_ui->xattr_names + host_ui->xattr_cnt; |
411 | if (!buffer) { |
412 | /* |
413 | * We should return the minimum buffer size which will fit a |
414 | * null-terminated list of all the extended attribute names. |
415 | */ |
416 | err = len; |
417 | goto out_err; |
418 | } |
419 | |
420 | if (len > size) { |
421 | err = -ERANGE; |
422 | goto out_err; |
423 | } |
424 | |
425 | lowest_xent_key(c, key: &key, inum: host->i_ino); |
426 | while (1) { |
427 | xent = ubifs_tnc_next_ent(c, key: &key, nm: &nm); |
428 | if (IS_ERR(ptr: xent)) { |
429 | err = PTR_ERR(ptr: xent); |
430 | break; |
431 | } |
432 | |
433 | fname_name(&nm) = xent->name; |
434 | fname_len(&nm) = le16_to_cpu(xent->nlen); |
435 | |
436 | if (xattr_visible(name: xent->name)) { |
437 | memcpy(buffer + written, fname_name(&nm), fname_len(&nm) + 1); |
438 | written += fname_len(&nm) + 1; |
439 | } |
440 | |
441 | kfree(objp: pxent); |
442 | pxent = xent; |
443 | key_read(c, from: &xent->key, to: &key); |
444 | } |
445 | kfree(objp: pxent); |
446 | up_read(sem: &host_ui->xattr_sem); |
447 | |
448 | if (err != -ENOENT) { |
449 | ubifs_err(c, fmt: "cannot find next direntry, error %d" , err); |
450 | return err; |
451 | } |
452 | |
453 | ubifs_assert(c, written <= size); |
454 | return written; |
455 | |
456 | out_err: |
457 | up_read(sem: &host_ui->xattr_sem); |
458 | return err; |
459 | } |
460 | |
461 | static int remove_xattr(struct ubifs_info *c, struct inode *host, |
462 | struct inode *inode, const struct fscrypt_name *nm) |
463 | { |
464 | int err; |
465 | struct ubifs_inode *host_ui = ubifs_inode(inode: host); |
466 | struct ubifs_inode *ui = ubifs_inode(inode); |
467 | struct ubifs_budget_req req = { .dirtied_ino = 2, .mod_dent = 1, |
468 | .dirtied_ino_d = ALIGN(host_ui->data_len, 8) }; |
469 | |
470 | ubifs_assert(c, ui->data_len == inode->i_size); |
471 | |
472 | err = ubifs_budget_space(c, req: &req); |
473 | if (err) |
474 | return err; |
475 | |
476 | mutex_lock(&host_ui->ui_mutex); |
477 | inode_set_ctime_current(inode: host); |
478 | host_ui->xattr_cnt -= 1; |
479 | host_ui->xattr_size -= CALC_DENT_SIZE(fname_len(nm)); |
480 | host_ui->xattr_size -= CALC_XATTR_BYTES(ui->data_len); |
481 | host_ui->xattr_names -= fname_len(nm); |
482 | |
483 | err = ubifs_jnl_delete_xattr(c, host, inode, nm); |
484 | if (err) |
485 | goto out_cancel; |
486 | mutex_unlock(lock: &host_ui->ui_mutex); |
487 | |
488 | ubifs_release_budget(c, req: &req); |
489 | return 0; |
490 | |
491 | out_cancel: |
492 | host_ui->xattr_cnt += 1; |
493 | host_ui->xattr_size += CALC_DENT_SIZE(fname_len(nm)); |
494 | host_ui->xattr_size += CALC_XATTR_BYTES(ui->data_len); |
495 | host_ui->xattr_names += fname_len(nm); |
496 | mutex_unlock(lock: &host_ui->ui_mutex); |
497 | ubifs_release_budget(c, req: &req); |
498 | make_bad_inode(inode); |
499 | return err; |
500 | } |
501 | |
502 | int ubifs_purge_xattrs(struct inode *host) |
503 | { |
504 | union ubifs_key key; |
505 | struct ubifs_info *c = host->i_sb->s_fs_info; |
506 | struct ubifs_dent_node *xent, *pxent = NULL; |
507 | struct inode *xino; |
508 | struct fscrypt_name nm = {0}; |
509 | int err; |
510 | |
511 | if (ubifs_inode(inode: host)->xattr_cnt <= ubifs_xattr_max_cnt(c)) |
512 | return 0; |
513 | |
514 | ubifs_warn(c, fmt: "inode %lu has too many xattrs, doing a non-atomic deletion" , |
515 | host->i_ino); |
516 | |
517 | down_write(sem: &ubifs_inode(inode: host)->xattr_sem); |
518 | lowest_xent_key(c, key: &key, inum: host->i_ino); |
519 | while (1) { |
520 | xent = ubifs_tnc_next_ent(c, key: &key, nm: &nm); |
521 | if (IS_ERR(ptr: xent)) { |
522 | err = PTR_ERR(ptr: xent); |
523 | break; |
524 | } |
525 | |
526 | fname_name(&nm) = xent->name; |
527 | fname_len(&nm) = le16_to_cpu(xent->nlen); |
528 | |
529 | xino = ubifs_iget(sb: c->vfs_sb, le64_to_cpu(xent->inum)); |
530 | if (IS_ERR(ptr: xino)) { |
531 | err = PTR_ERR(ptr: xino); |
532 | ubifs_err(c, fmt: "dead directory entry '%s', error %d" , |
533 | xent->name, err); |
534 | ubifs_ro_mode(c, err); |
535 | kfree(objp: pxent); |
536 | kfree(objp: xent); |
537 | goto out_err; |
538 | } |
539 | |
540 | ubifs_assert(c, ubifs_inode(xino)->xattr); |
541 | |
542 | clear_nlink(inode: xino); |
543 | err = remove_xattr(c, host, inode: xino, nm: &nm); |
544 | if (err) { |
545 | kfree(objp: pxent); |
546 | kfree(objp: xent); |
547 | iput(xino); |
548 | ubifs_err(c, fmt: "cannot remove xattr, error %d" , err); |
549 | goto out_err; |
550 | } |
551 | |
552 | iput(xino); |
553 | |
554 | kfree(objp: pxent); |
555 | pxent = xent; |
556 | key_read(c, from: &xent->key, to: &key); |
557 | } |
558 | kfree(objp: pxent); |
559 | up_write(sem: &ubifs_inode(inode: host)->xattr_sem); |
560 | |
561 | if (err != -ENOENT) { |
562 | ubifs_err(c, fmt: "cannot find next direntry, error %d" , err); |
563 | return err; |
564 | } |
565 | |
566 | return 0; |
567 | |
568 | out_err: |
569 | up_write(sem: &ubifs_inode(inode: host)->xattr_sem); |
570 | return err; |
571 | } |
572 | |
573 | /** |
574 | * ubifs_evict_xattr_inode - Evict an xattr inode. |
575 | * @c: UBIFS file-system description object |
576 | * @xattr_inum: xattr inode number |
577 | * |
578 | * When an inode that hosts xattrs is being removed we have to make sure |
579 | * that cached inodes of the xattrs also get removed from the inode cache |
580 | * otherwise we'd waste memory. This function looks up an inode from the |
581 | * inode cache and clears the link counter such that iput() will evict |
582 | * the inode. |
583 | */ |
584 | void ubifs_evict_xattr_inode(struct ubifs_info *c, ino_t xattr_inum) |
585 | { |
586 | struct inode *inode; |
587 | |
588 | inode = ilookup(sb: c->vfs_sb, ino: xattr_inum); |
589 | if (inode) { |
590 | clear_nlink(inode); |
591 | iput(inode); |
592 | } |
593 | } |
594 | |
595 | static int ubifs_xattr_remove(struct inode *host, const char *name) |
596 | { |
597 | struct inode *inode; |
598 | struct ubifs_info *c = host->i_sb->s_fs_info; |
599 | struct fscrypt_name nm = { .disk_name = FSTR_INIT((char *)name, strlen(name))}; |
600 | struct ubifs_dent_node *xent; |
601 | union ubifs_key key; |
602 | int err; |
603 | |
604 | ubifs_assert(c, inode_is_locked(host)); |
605 | |
606 | if (fname_len(&nm) > UBIFS_MAX_NLEN) |
607 | return -ENAMETOOLONG; |
608 | |
609 | xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS); |
610 | if (!xent) |
611 | return -ENOMEM; |
612 | |
613 | down_write(sem: &ubifs_inode(inode: host)->xattr_sem); |
614 | xent_key_init(c, key: &key, inum: host->i_ino, nm: &nm); |
615 | err = ubifs_tnc_lookup_nm(c, key: &key, node: xent, nm: &nm); |
616 | if (err) { |
617 | if (err == -ENOENT) |
618 | err = -ENODATA; |
619 | goto out_free; |
620 | } |
621 | |
622 | inode = iget_xattr(c, le64_to_cpu(xent->inum)); |
623 | if (IS_ERR(ptr: inode)) { |
624 | err = PTR_ERR(ptr: inode); |
625 | goto out_free; |
626 | } |
627 | |
628 | ubifs_assert(c, inode->i_nlink == 1); |
629 | clear_nlink(inode); |
630 | err = remove_xattr(c, host, inode, nm: &nm); |
631 | if (err) |
632 | set_nlink(inode, nlink: 1); |
633 | |
634 | /* If @i_nlink is 0, 'iput()' will delete the inode */ |
635 | iput(inode); |
636 | |
637 | out_free: |
638 | up_write(sem: &ubifs_inode(inode: host)->xattr_sem); |
639 | kfree(objp: xent); |
640 | return err; |
641 | } |
642 | |
643 | #ifdef CONFIG_UBIFS_FS_SECURITY |
644 | static int init_xattrs(struct inode *inode, const struct xattr *xattr_array, |
645 | void *fs_info) |
646 | { |
647 | const struct xattr *xattr; |
648 | char *name; |
649 | int err = 0; |
650 | |
651 | for (xattr = xattr_array; xattr->name != NULL; xattr++) { |
652 | name = kmalloc(XATTR_SECURITY_PREFIX_LEN + |
653 | strlen(xattr->name) + 1, GFP_NOFS); |
654 | if (!name) { |
655 | err = -ENOMEM; |
656 | break; |
657 | } |
658 | strcpy(p: name, XATTR_SECURITY_PREFIX); |
659 | strcpy(p: name + XATTR_SECURITY_PREFIX_LEN, q: xattr->name); |
660 | /* |
661 | * creating a new inode without holding the inode rwsem, |
662 | * no need to check whether inode is locked. |
663 | */ |
664 | err = ubifs_xattr_set(host: inode, name, value: xattr->value, |
665 | size: xattr->value_len, flags: 0, check_lock: false); |
666 | kfree(objp: name); |
667 | if (err < 0) |
668 | break; |
669 | } |
670 | |
671 | return err; |
672 | } |
673 | |
674 | int ubifs_init_security(struct inode *dentry, struct inode *inode, |
675 | const struct qstr *qstr) |
676 | { |
677 | int err; |
678 | |
679 | err = security_inode_init_security(inode, dir: dentry, qstr, |
680 | initxattrs: &init_xattrs, NULL); |
681 | if (err) { |
682 | struct ubifs_info *c = dentry->i_sb->s_fs_info; |
683 | ubifs_err(c, fmt: "cannot initialize security for inode %lu, error %d" , |
684 | inode->i_ino, err); |
685 | } |
686 | return err; |
687 | } |
688 | #endif |
689 | |
690 | static int xattr_get(const struct xattr_handler *handler, |
691 | struct dentry *dentry, struct inode *inode, |
692 | const char *name, void *buffer, size_t size) |
693 | { |
694 | dbg_gen("xattr '%s', ino %lu ('%pd'), buf size %zd" , name, |
695 | inode->i_ino, dentry, size); |
696 | |
697 | name = xattr_full_name(handler, name); |
698 | return ubifs_xattr_get(host: inode, name, buf: buffer, size); |
699 | } |
700 | |
701 | static int xattr_set(const struct xattr_handler *handler, |
702 | struct mnt_idmap *idmap, |
703 | struct dentry *dentry, struct inode *inode, |
704 | const char *name, const void *value, |
705 | size_t size, int flags) |
706 | { |
707 | dbg_gen("xattr '%s', host ino %lu ('%pd'), size %zd" , |
708 | name, inode->i_ino, dentry, size); |
709 | |
710 | name = xattr_full_name(handler, name); |
711 | |
712 | if (value) |
713 | return ubifs_xattr_set(host: inode, name, value, size, flags, check_lock: true); |
714 | else |
715 | return ubifs_xattr_remove(host: inode, name); |
716 | } |
717 | |
718 | static const struct xattr_handler ubifs_user_xattr_handler = { |
719 | .prefix = XATTR_USER_PREFIX, |
720 | .get = xattr_get, |
721 | .set = xattr_set, |
722 | }; |
723 | |
724 | static const struct xattr_handler ubifs_trusted_xattr_handler = { |
725 | .prefix = XATTR_TRUSTED_PREFIX, |
726 | .get = xattr_get, |
727 | .set = xattr_set, |
728 | }; |
729 | |
730 | #ifdef CONFIG_UBIFS_FS_SECURITY |
731 | static const struct xattr_handler ubifs_security_xattr_handler = { |
732 | .prefix = XATTR_SECURITY_PREFIX, |
733 | .get = xattr_get, |
734 | .set = xattr_set, |
735 | }; |
736 | #endif |
737 | |
738 | const struct xattr_handler * const ubifs_xattr_handlers[] = { |
739 | &ubifs_user_xattr_handler, |
740 | &ubifs_trusted_xattr_handler, |
741 | #ifdef CONFIG_UBIFS_FS_SECURITY |
742 | &ubifs_security_xattr_handler, |
743 | #endif |
744 | NULL |
745 | }; |
746 | |