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1/*
2 * This file is part of UBIFS.
3 *
4 * Copyright (C) 2006-2008 Nokia Corporation.
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published by
8 * the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * more details.
14 *
15 * You should have received a copy of the GNU General Public License along with
16 * this program; if not, write to the Free Software Foundation, Inc., 51
17 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18 *
19 * Authors: Artem Bityutskiy (Битюцкий Артём)
20 * Adrian Hunter
21 */
22
23/*
24 * This file implements UBIFS extended attributes support.
25 *
26 * Extended attributes are implemented as regular inodes with attached data,
27 * which limits extended attribute size to UBIFS block size (4KiB). Names of
28 * extended attributes are described by extended attribute entries (xentries),
29 * which are almost identical to directory entries, but have different key type.
30 *
31 * In other words, the situation with extended attributes is very similar to
32 * directories. Indeed, any inode (but of course not xattr inodes) may have a
33 * number of associated xentries, just like directory inodes have associated
34 * directory entries. Extended attribute entries store the name of the extended
35 * attribute, the host inode number, and the extended attribute inode number.
36 * Similarly, direntries store the name, the parent and the target inode
37 * numbers. Thus, most of the common UBIFS mechanisms may be re-used for
38 * extended attributes.
39 *
40 * The number of extended attributes is not limited, but there is Linux
41 * limitation on the maximum possible size of the list of all extended
42 * attributes associated with an inode (%XATTR_LIST_MAX), so UBIFS makes sure
43 * the sum of all extended attribute names of the inode does not exceed that
44 * limit.
45 *
46 * Extended attributes are synchronous, which means they are written to the
47 * flash media synchronously and there is no write-back for extended attribute
48 * inodes. The extended attribute values are not stored in compressed form on
49 * the media.
50 *
51 * Since extended attributes are represented by regular inodes, they are cached
52 * in the VFS inode cache. The xentries are cached in the LNC cache (see
53 * tnc.c).
54 *
55 * ACL support is not implemented.
56 */
57
58#include "ubifs.h"
59#include <linux/fs.h>
60#include <linux/slab.h>
61#include <linux/xattr.h>
62
63/*
64 * Limit the number of extended attributes per inode so that the total size
65 * (@xattr_size) is guaranteeded to fit in an 'unsigned int'.
66 */
67#define MAX_XATTRS_PER_INODE 65535
68
69/*
70 * Extended attribute type constants.
71 *
72 * USER_XATTR: user extended attribute ("user.*")
73 * TRUSTED_XATTR: trusted extended attribute ("trusted.*)
74 * SECURITY_XATTR: security extended attribute ("security.*")
75 */
76enum {
77 USER_XATTR,
78 TRUSTED_XATTR,
79 SECURITY_XATTR,
80};
81
82static const struct inode_operations empty_iops;
83static const struct file_operations empty_fops;
84
85/**
86 * create_xattr - create an extended attribute.
87 * @c: UBIFS file-system description object
88 * @host: host inode
89 * @nm: extended attribute name
90 * @value: extended attribute value
91 * @size: size of extended attribute value
92 *
93 * This is a helper function which creates an extended attribute of name @nm
94 * and value @value for inode @host. The host inode is also updated on flash
95 * because the ctime and extended attribute accounting data changes. This
96 * function returns zero in case of success and a negative error code in case
97 * of failure.
98 */
99static int create_xattr(struct ubifs_info *c, struct inode *host,
100 const struct qstr *nm, const void *value, int size)
101{
102 int err, names_len;
103 struct inode *inode;
104 struct ubifs_inode *ui, *host_ui = ubifs_inode(host);
105 struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1,
106 .new_ino_d = ALIGN(size, 8), .dirtied_ino = 1,
107 .dirtied_ino_d = ALIGN(host_ui->data_len, 8) };
108
109 if (host_ui->xattr_cnt >= MAX_XATTRS_PER_INODE) {
110 ubifs_err(c, "inode %lu already has too many xattrs (%d), cannot create more",
111 host->i_ino, host_ui->xattr_cnt);
112 return -ENOSPC;
113 }
114 /*
115 * Linux limits the maximum size of the extended attribute names list
116 * to %XATTR_LIST_MAX. This means we should not allow creating more
117 * extended attributes if the name list becomes larger. This limitation
118 * is artificial for UBIFS, though.
119 */
120 names_len = host_ui->xattr_names + host_ui->xattr_cnt + nm->len + 1;
121 if (names_len > XATTR_LIST_MAX) {
122 ubifs_err(c, "cannot add one more xattr name to inode %lu, total names length would become %d, max. is %d",
123 host->i_ino, names_len, XATTR_LIST_MAX);
124 return -ENOSPC;
125 }
126
127 err = ubifs_budget_space(c, &req);
128 if (err)
129 return err;
130
131 inode = ubifs_new_inode(c, host, S_IFREG | S_IRWXUGO);
132 if (IS_ERR(inode)) {
133 err = PTR_ERR(inode);
134 goto out_budg;
135 }
136
137 /* Re-define all operations to be "nothing" */
138 inode->i_mapping->a_ops = &empty_aops;
139 inode->i_op = &empty_iops;
140 inode->i_fop = &empty_fops;
141
142 inode->i_flags |= S_SYNC | S_NOATIME | S_NOCMTIME | S_NOQUOTA;
143 ui = ubifs_inode(inode);
144 ui->xattr = 1;
145 ui->flags |= UBIFS_XATTR_FL;
146 ui->data = kmemdup(value, size, GFP_NOFS);
147 if (!ui->data) {
148 err = -ENOMEM;
149 goto out_free;
150 }
151 inode->i_size = ui->ui_size = size;
152 ui->data_len = size;
153
154 mutex_lock(&host_ui->ui_mutex);
155 host->i_ctime = ubifs_current_time(host);
156 host_ui->xattr_cnt += 1;
157 host_ui->xattr_size += CALC_DENT_SIZE(nm->len);
158 host_ui->xattr_size += CALC_XATTR_BYTES(size);
159 host_ui->xattr_names += nm->len;
160
161 err = ubifs_jnl_update(c, host, nm, inode, 0, 1);
162 if (err)
163 goto out_cancel;
164 mutex_unlock(&host_ui->ui_mutex);
165
166 ubifs_release_budget(c, &req);
167 insert_inode_hash(inode);
168 iput(inode);
169 return 0;
170
171out_cancel:
172 host_ui->xattr_cnt -= 1;
173 host_ui->xattr_size -= CALC_DENT_SIZE(nm->len);
174 host_ui->xattr_size -= CALC_XATTR_BYTES(size);
175 mutex_unlock(&host_ui->ui_mutex);
176out_free:
177 make_bad_inode(inode);
178 iput(inode);
179out_budg:
180 ubifs_release_budget(c, &req);
181 return err;
182}
183
184/**
185 * change_xattr - change an extended attribute.
186 * @c: UBIFS file-system description object
187 * @host: host inode
188 * @inode: extended attribute inode
189 * @value: extended attribute value
190 * @size: size of extended attribute value
191 *
192 * This helper function changes the value of extended attribute @inode with new
193 * data from @value. Returns zero in case of success and a negative error code
194 * in case of failure.
195 */
196static int change_xattr(struct ubifs_info *c, struct inode *host,
197 struct inode *inode, const void *value, int size)
198{
199 int err;
200 struct ubifs_inode *host_ui = ubifs_inode(host);
201 struct ubifs_inode *ui = ubifs_inode(inode);
202 void *buf = NULL;
203 struct ubifs_budget_req req = { .dirtied_ino = 2,
204 .dirtied_ino_d = ALIGN(size, 8) + ALIGN(host_ui->data_len, 8) };
205
206 ubifs_assert(ui->data_len == inode->i_size);
207 err = ubifs_budget_space(c, &req);
208 if (err)
209 return err;
210
211 buf = kmemdup(value, size, GFP_NOFS);
212 if (!buf) {
213 err = -ENOMEM;
214 goto out_free;
215 }
216 mutex_lock(&ui->ui_mutex);
217 kfree(ui->data);
218 ui->data = buf;
219 inode->i_size = ui->ui_size = size;
220 ui->data_len = size;
221 mutex_unlock(&ui->ui_mutex);
222
223 mutex_lock(&host_ui->ui_mutex);
224 host->i_ctime = ubifs_current_time(host);
225 host_ui->xattr_size -= CALC_XATTR_BYTES(ui->data_len);
226 host_ui->xattr_size += CALC_XATTR_BYTES(size);
227
228 /*
229 * It is important to write the host inode after the xattr inode
230 * because if the host inode gets synchronized (via 'fsync()'), then
231 * the extended attribute inode gets synchronized, because it goes
232 * before the host inode in the write-buffer.
233 */
234 err = ubifs_jnl_change_xattr(c, inode, host);
235 if (err)
236 goto out_cancel;
237 mutex_unlock(&host_ui->ui_mutex);
238
239 ubifs_release_budget(c, &req);
240 return 0;
241
242out_cancel:
243 host_ui->xattr_size -= CALC_XATTR_BYTES(size);
244 host_ui->xattr_size += CALC_XATTR_BYTES(ui->data_len);
245 mutex_unlock(&host_ui->ui_mutex);
246 make_bad_inode(inode);
247out_free:
248 ubifs_release_budget(c, &req);
249 return err;
250}
251
252/**
253 * check_namespace - check extended attribute name-space.
254 * @nm: extended attribute name
255 *
256 * This function makes sure the extended attribute name belongs to one of the
257 * supported extended attribute name-spaces. Returns name-space index in case
258 * of success and a negative error code in case of failure.
259 */
260static int check_namespace(const struct qstr *nm)
261{
262 int type;
263
264 if (nm->len > UBIFS_MAX_NLEN)
265 return -ENAMETOOLONG;
266
267 if (!strncmp(nm->name, XATTR_TRUSTED_PREFIX,
268 XATTR_TRUSTED_PREFIX_LEN)) {
269 if (nm->name[XATTR_TRUSTED_PREFIX_LEN] == '\0')
270 return -EINVAL;
271 type = TRUSTED_XATTR;
272 } else if (!strncmp(nm->name, XATTR_USER_PREFIX,
273 XATTR_USER_PREFIX_LEN)) {
274 if (nm->name[XATTR_USER_PREFIX_LEN] == '\0')
275 return -EINVAL;
276 type = USER_XATTR;
277 } else if (!strncmp(nm->name, XATTR_SECURITY_PREFIX,
278 XATTR_SECURITY_PREFIX_LEN)) {
279 if (nm->name[XATTR_SECURITY_PREFIX_LEN] == '\0')
280 return -EINVAL;
281 type = SECURITY_XATTR;
282 } else
283 return -EOPNOTSUPP;
284
285 return type;
286}
287
288static struct inode *iget_xattr(struct ubifs_info *c, ino_t inum)
289{
290 struct inode *inode;
291
292 inode = ubifs_iget(c->vfs_sb, inum);
293 if (IS_ERR(inode)) {
294 ubifs_err(c, "dead extended attribute entry, error %d",
295 (int)PTR_ERR(inode));
296 return inode;
297 }
298 if (ubifs_inode(inode)->xattr)
299 return inode;
300 ubifs_err(c, "corrupt extended attribute entry");
301 iput(inode);
302 return ERR_PTR(-EINVAL);
303}
304
305static int setxattr(struct inode *host, const char *name, const void *value,
306 size_t size, int flags)
307{
308 struct inode *inode;
309 struct ubifs_info *c = host->i_sb->s_fs_info;
310 struct qstr nm = QSTR_INIT(name, strlen(name));
311 struct ubifs_dent_node *xent;
312 union ubifs_key key;
313 int err, type;
314
315 ubifs_assert(inode_is_locked(host));
316
317 if (size > UBIFS_MAX_INO_DATA)
318 return -ERANGE;
319
320 type = check_namespace(&nm);
321 if (type < 0)
322 return type;
323
324 xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
325 if (!xent)
326 return -ENOMEM;
327
328 /*
329 * The extended attribute entries are stored in LNC, so multiple
330 * look-ups do not involve reading the flash.
331 */
332 xent_key_init(c, &key, host->i_ino, &nm);
333 err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
334 if (err) {
335 if (err != -ENOENT)
336 goto out_free;
337
338 if (flags & XATTR_REPLACE)
339 /* We are asked not to create the xattr */
340 err = -ENODATA;
341 else
342 err = create_xattr(c, host, &nm, value, size);
343 goto out_free;
344 }
345
346 if (flags & XATTR_CREATE) {
347 /* We are asked not to replace the xattr */
348 err = -EEXIST;
349 goto out_free;
350 }
351
352 inode = iget_xattr(c, le64_to_cpu(xent->inum));
353 if (IS_ERR(inode)) {
354 err = PTR_ERR(inode);
355 goto out_free;
356 }
357
358 err = change_xattr(c, host, inode, value, size);
359 iput(inode);
360
361out_free:
362 kfree(xent);
363 return err;
364}
365
366int ubifs_setxattr(struct dentry *dentry, const char *name,
367 const void *value, size_t size, int flags)
368{
369 dbg_gen("xattr '%s', host ino %lu ('%pd'), size %zd",
370 name, d_inode(dentry)->i_ino, dentry, size);
371
372 return setxattr(d_inode(dentry), name, value, size, flags);
373}
374
375ssize_t ubifs_getxattr(struct dentry *dentry, const char *name, void *buf,
376 size_t size)
377{
378 struct inode *inode, *host = d_inode(dentry);
379 struct ubifs_info *c = host->i_sb->s_fs_info;
380 struct qstr nm = QSTR_INIT(name, strlen(name));
381 struct ubifs_inode *ui;
382 struct ubifs_dent_node *xent;
383 union ubifs_key key;
384 int err;
385
386 dbg_gen("xattr '%s', ino %lu ('%pd'), buf size %zd", name,
387 host->i_ino, dentry, size);
388
389 err = check_namespace(&nm);
390 if (err < 0)
391 return err;
392
393 xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
394 if (!xent)
395 return -ENOMEM;
396
397 xent_key_init(c, &key, host->i_ino, &nm);
398 err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
399 if (err) {
400 if (err == -ENOENT)
401 err = -ENODATA;
402 goto out_unlock;
403 }
404
405 inode = iget_xattr(c, le64_to_cpu(xent->inum));
406 if (IS_ERR(inode)) {
407 err = PTR_ERR(inode);
408 goto out_unlock;
409 }
410
411 ui = ubifs_inode(inode);
412 ubifs_assert(inode->i_size == ui->data_len);
413 ubifs_assert(ubifs_inode(host)->xattr_size > ui->data_len);
414
415 mutex_lock(&ui->ui_mutex);
416 if (buf) {
417 /* If @buf is %NULL we are supposed to return the length */
418 if (ui->data_len > size) {
419 ubifs_err(c, "buffer size %zd, xattr len %d",
420 size, ui->data_len);
421 err = -ERANGE;
422 goto out_iput;
423 }
424
425 memcpy(buf, ui->data, ui->data_len);
426 }
427 err = ui->data_len;
428
429out_iput:
430 mutex_unlock(&ui->ui_mutex);
431 iput(inode);
432out_unlock:
433 kfree(xent);
434 return err;
435}
436
437ssize_t ubifs_listxattr(struct dentry *dentry, char *buffer, size_t size)
438{
439 union ubifs_key key;
440 struct inode *host = d_inode(dentry);
441 struct ubifs_info *c = host->i_sb->s_fs_info;
442 struct ubifs_inode *host_ui = ubifs_inode(host);
443 struct ubifs_dent_node *xent, *pxent = NULL;
444 int err, len, written = 0;
445 struct qstr nm = { .name = NULL };
446
447 dbg_gen("ino %lu ('%pd'), buffer size %zd", host->i_ino,
448 dentry, size);
449
450 len = host_ui->xattr_names + host_ui->xattr_cnt;
451 if (!buffer)
452 /*
453 * We should return the minimum buffer size which will fit a
454 * null-terminated list of all the extended attribute names.
455 */
456 return len;
457
458 if (len > size)
459 return -ERANGE;
460
461 lowest_xent_key(c, &key, host->i_ino);
462 while (1) {
463 int type;
464
465 xent = ubifs_tnc_next_ent(c, &key, &nm);
466 if (IS_ERR(xent)) {
467 err = PTR_ERR(xent);
468 break;
469 }
470
471 nm.name = xent->name;
472 nm.len = le16_to_cpu(xent->nlen);
473
474 type = check_namespace(&nm);
475 if (unlikely(type < 0)) {
476 err = type;
477 break;
478 }
479
480 /* Show trusted namespace only for "power" users */
481 if (type != TRUSTED_XATTR || capable(CAP_SYS_ADMIN)) {
482 memcpy(buffer + written, nm.name, nm.len + 1);
483 written += nm.len + 1;
484 }
485
486 kfree(pxent);
487 pxent = xent;
488 key_read(c, &xent->key, &key);
489 }
490
491 kfree(pxent);
492 if (err != -ENOENT) {
493 ubifs_err(c, "cannot find next direntry, error %d", err);
494 return err;
495 }
496
497 ubifs_assert(written <= size);
498 return written;
499}
500
501static int remove_xattr(struct ubifs_info *c, struct inode *host,
502 struct inode *inode, const struct qstr *nm)
503{
504 int err;
505 struct ubifs_inode *host_ui = ubifs_inode(host);
506 struct ubifs_inode *ui = ubifs_inode(inode);
507 struct ubifs_budget_req req = { .dirtied_ino = 2, .mod_dent = 1,
508 .dirtied_ino_d = ALIGN(host_ui->data_len, 8) };
509
510 ubifs_assert(ui->data_len == inode->i_size);
511
512 err = ubifs_budget_space(c, &req);
513 if (err)
514 return err;
515
516 mutex_lock(&host_ui->ui_mutex);
517 host->i_ctime = ubifs_current_time(host);
518 host_ui->xattr_cnt -= 1;
519 host_ui->xattr_size -= CALC_DENT_SIZE(nm->len);
520 host_ui->xattr_size -= CALC_XATTR_BYTES(ui->data_len);
521 host_ui->xattr_names -= nm->len;
522
523 err = ubifs_jnl_delete_xattr(c, host, inode, nm);
524 if (err)
525 goto out_cancel;
526 mutex_unlock(&host_ui->ui_mutex);
527
528 ubifs_release_budget(c, &req);
529 return 0;
530
531out_cancel:
532 host_ui->xattr_cnt += 1;
533 host_ui->xattr_size += CALC_DENT_SIZE(nm->len);
534 host_ui->xattr_size += CALC_XATTR_BYTES(ui->data_len);
535 mutex_unlock(&host_ui->ui_mutex);
536 ubifs_release_budget(c, &req);
537 make_bad_inode(inode);
538 return err;
539}
540
541int ubifs_removexattr(struct dentry *dentry, const char *name)
542{
543 struct inode *inode, *host = d_inode(dentry);
544 struct ubifs_info *c = host->i_sb->s_fs_info;
545 struct qstr nm = QSTR_INIT(name, strlen(name));
546 struct ubifs_dent_node *xent;
547 union ubifs_key key;
548 int err;
549
550 dbg_gen("xattr '%s', ino %lu ('%pd')", name,
551 host->i_ino, dentry);
552 ubifs_assert(inode_is_locked(host));
553
554 err = check_namespace(&nm);
555 if (err < 0)
556 return err;
557
558 xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
559 if (!xent)
560 return -ENOMEM;
561
562 xent_key_init(c, &key, host->i_ino, &nm);
563 err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
564 if (err) {
565 if (err == -ENOENT)
566 err = -ENODATA;
567 goto out_free;
568 }
569
570 inode = iget_xattr(c, le64_to_cpu(xent->inum));
571 if (IS_ERR(inode)) {
572 err = PTR_ERR(inode);
573 goto out_free;
574 }
575
576 ubifs_assert(inode->i_nlink == 1);
577 clear_nlink(inode);
578 err = remove_xattr(c, host, inode, &nm);
579 if (err)
580 set_nlink(inode, 1);
581
582 /* If @i_nlink is 0, 'iput()' will delete the inode */
583 iput(inode);
584
585out_free:
586 kfree(xent);
587 return err;
588}
589
590static int init_xattrs(struct inode *inode, const struct xattr *xattr_array,
591 void *fs_info)
592{
593 const struct xattr *xattr;
594 char *name;
595 int err = 0;
596
597 for (xattr = xattr_array; xattr->name != NULL; xattr++) {
598 name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
599 strlen(xattr->name) + 1, GFP_NOFS);
600 if (!name) {
601 err = -ENOMEM;
602 break;
603 }
604 strcpy(name, XATTR_SECURITY_PREFIX);
605 strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
606 err = setxattr(inode, name, xattr->value, xattr->value_len, 0);
607 kfree(name);
608 if (err < 0)
609 break;
610 }
611
612 return err;
613}
614
615int ubifs_init_security(struct inode *dentry, struct inode *inode,
616 const struct qstr *qstr)
617{
618 int err;
619
620 err = security_inode_init_security(inode, dentry, qstr,
621 &init_xattrs, 0);
622 if (err) {
623 struct ubifs_info *c = dentry->i_sb->s_fs_info;
624 ubifs_err(c, "cannot initialize security for inode %lu, error %d",
625 inode->i_ino, err);
626 }
627 return err;
628}
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
51static const struct inode_operations empty_iops;
52static const struct file_operations empty_fops;
53
54/**
55 * create_xattr - create an extended attribute.
56 * @c: UBIFS file-system description object
57 * @host: host inode
58 * @nm: extended attribute name
59 * @value: extended attribute value
60 * @size: size of extended attribute value
61 *
62 * This is a helper function which creates an extended attribute of name @nm
63 * and value @value for inode @host. The host inode is also updated on flash
64 * because the ctime and extended attribute accounting data changes. This
65 * function returns zero in case of success and a negative error code in case
66 * of failure.
67 */
68static int create_xattr(struct ubifs_info *c, struct inode *host,
69 const struct fscrypt_name *nm, const void *value, int size)
70{
71 int err, names_len;
72 struct inode *inode;
73 struct ubifs_inode *ui, *host_ui = ubifs_inode(host);
74 struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1,
75 .new_ino_d = ALIGN(size, 8), .dirtied_ino = 1,
76 .dirtied_ino_d = ALIGN(host_ui->data_len, 8) };
77
78 if (host_ui->xattr_cnt >= ubifs_xattr_max_cnt(c)) {
79 ubifs_err(c, "inode %lu already has too many xattrs (%d), cannot create more",
80 host->i_ino, host_ui->xattr_cnt);
81 return -ENOSPC;
82 }
83 /*
84 * Linux limits the maximum size of the extended attribute names list
85 * to %XATTR_LIST_MAX. This means we should not allow creating more
86 * extended attributes if the name list becomes larger. This limitation
87 * is artificial for UBIFS, though.
88 */
89 names_len = host_ui->xattr_names + host_ui->xattr_cnt + fname_len(nm) + 1;
90 if (names_len > XATTR_LIST_MAX) {
91 ubifs_err(c, "cannot add one more xattr name to inode %lu, total names length would become %d, max. is %d",
92 host->i_ino, names_len, XATTR_LIST_MAX);
93 return -ENOSPC;
94 }
95
96 err = ubifs_budget_space(c, &req);
97 if (err)
98 return err;
99
100 inode = ubifs_new_inode(c, host, S_IFREG | S_IRWXUGO, true);
101 if (IS_ERR(inode)) {
102 err = PTR_ERR(inode);
103 goto out_budg;
104 }
105
106 /* Re-define all operations to be "nothing" */
107 inode->i_mapping->a_ops = &empty_aops;
108 inode->i_op = &empty_iops;
109 inode->i_fop = &empty_fops;
110
111 inode->i_flags |= S_SYNC | S_NOATIME | S_NOCMTIME;
112 ui = ubifs_inode(inode);
113 ui->xattr = 1;
114 ui->flags |= UBIFS_XATTR_FL;
115 ui->data = kmemdup(value, size, GFP_NOFS);
116 if (!ui->data) {
117 err = -ENOMEM;
118 goto out_free;
119 }
120 inode->i_size = ui->ui_size = size;
121 ui->data_len = size;
122
123 mutex_lock(&host_ui->ui_mutex);
124 inode_set_ctime_current(host);
125 host_ui->xattr_cnt += 1;
126 host_ui->xattr_size += CALC_DENT_SIZE(fname_len(nm));
127 host_ui->xattr_size += CALC_XATTR_BYTES(size);
128 host_ui->xattr_names += fname_len(nm);
129
130 /*
131 * We handle UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT here because we
132 * have to set the UBIFS_CRYPT_FL flag on the host inode.
133 * To avoid multiple updates of the same inode in the same operation,
134 * let's do it here.
135 */
136 if (strcmp(fname_name(nm), UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT) == 0)
137 host_ui->flags |= UBIFS_CRYPT_FL;
138
139 err = ubifs_jnl_update(c, host, nm, inode, 0, 1, 0);
140 if (err)
141 goto out_cancel;
142 ubifs_set_inode_flags(host);
143 mutex_unlock(&host_ui->ui_mutex);
144
145 ubifs_release_budget(c, &req);
146 insert_inode_hash(inode);
147 iput(inode);
148 return 0;
149
150out_cancel:
151 host_ui->xattr_cnt -= 1;
152 host_ui->xattr_size -= CALC_DENT_SIZE(fname_len(nm));
153 host_ui->xattr_size -= CALC_XATTR_BYTES(size);
154 host_ui->xattr_names -= fname_len(nm);
155 host_ui->flags &= ~UBIFS_CRYPT_FL;
156 mutex_unlock(&host_ui->ui_mutex);
157out_free:
158 make_bad_inode(inode);
159 iput(inode);
160out_budg:
161 ubifs_release_budget(c, &req);
162 return err;
163}
164
165/**
166 * change_xattr - change an extended attribute.
167 * @c: UBIFS file-system description object
168 * @host: host inode
169 * @inode: extended attribute inode
170 * @value: extended attribute value
171 * @size: size of extended attribute value
172 *
173 * This helper function changes the value of extended attribute @inode with new
174 * data from @value. Returns zero in case of success and a negative error code
175 * in case of failure.
176 */
177static int change_xattr(struct ubifs_info *c, struct inode *host,
178 struct inode *inode, const void *value, int size)
179{
180 int err;
181 struct ubifs_inode *host_ui = ubifs_inode(host);
182 struct ubifs_inode *ui = ubifs_inode(inode);
183 void *buf = NULL;
184 int old_size;
185 struct ubifs_budget_req req = { .dirtied_ino = 2,
186 .dirtied_ino_d = ALIGN(size, 8) + ALIGN(host_ui->data_len, 8) };
187
188 ubifs_assert(c, ui->data_len == inode->i_size);
189 err = ubifs_budget_space(c, &req);
190 if (err)
191 return err;
192
193 buf = kmemdup(value, size, GFP_NOFS);
194 if (!buf) {
195 err = -ENOMEM;
196 goto out_free;
197 }
198 kfree(ui->data);
199 ui->data = buf;
200 inode->i_size = ui->ui_size = size;
201 old_size = ui->data_len;
202 ui->data_len = size;
203
204 mutex_lock(&host_ui->ui_mutex);
205 inode_set_ctime_current(host);
206 host_ui->xattr_size -= CALC_XATTR_BYTES(old_size);
207 host_ui->xattr_size += CALC_XATTR_BYTES(size);
208
209 /*
210 * It is important to write the host inode after the xattr inode
211 * because if the host inode gets synchronized (via 'fsync()'), then
212 * the extended attribute inode gets synchronized, because it goes
213 * before the host inode in the write-buffer.
214 */
215 err = ubifs_jnl_change_xattr(c, inode, host);
216 if (err)
217 goto out_cancel;
218 mutex_unlock(&host_ui->ui_mutex);
219
220 ubifs_release_budget(c, &req);
221 return 0;
222
223out_cancel:
224 host_ui->xattr_size -= CALC_XATTR_BYTES(size);
225 host_ui->xattr_size += CALC_XATTR_BYTES(old_size);
226 mutex_unlock(&host_ui->ui_mutex);
227 make_bad_inode(inode);
228out_free:
229 ubifs_release_budget(c, &req);
230 return err;
231}
232
233static struct inode *iget_xattr(struct ubifs_info *c, ino_t inum)
234{
235 struct inode *inode;
236
237 inode = ubifs_iget(c->vfs_sb, inum);
238 if (IS_ERR(inode)) {
239 ubifs_err(c, "dead extended attribute entry, error %d",
240 (int)PTR_ERR(inode));
241 return inode;
242 }
243 if (ubifs_inode(inode)->xattr)
244 return inode;
245 ubifs_err(c, "corrupt extended attribute entry");
246 iput(inode);
247 return ERR_PTR(-EINVAL);
248}
249
250int ubifs_xattr_set(struct inode *host, const char *name, const void *value,
251 size_t size, int flags, bool check_lock)
252{
253 struct inode *inode;
254 struct ubifs_info *c = host->i_sb->s_fs_info;
255 struct fscrypt_name nm = { .disk_name = FSTR_INIT((char *)name, strlen(name))};
256 struct ubifs_dent_node *xent;
257 union ubifs_key key;
258 int err;
259
260 if (check_lock)
261 ubifs_assert(c, inode_is_locked(host));
262
263 if (size > UBIFS_MAX_INO_DATA)
264 return -ERANGE;
265
266 if (fname_len(&nm) > UBIFS_MAX_NLEN)
267 return -ENAMETOOLONG;
268
269 xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
270 if (!xent)
271 return -ENOMEM;
272
273 down_write(&ubifs_inode(host)->xattr_sem);
274 /*
275 * The extended attribute entries are stored in LNC, so multiple
276 * look-ups do not involve reading the flash.
277 */
278 xent_key_init(c, &key, host->i_ino, &nm);
279 err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
280 if (err) {
281 if (err != -ENOENT)
282 goto out_free;
283
284 if (flags & XATTR_REPLACE)
285 /* We are asked not to create the xattr */
286 err = -ENODATA;
287 else
288 err = create_xattr(c, host, &nm, value, size);
289 goto out_free;
290 }
291
292 if (flags & XATTR_CREATE) {
293 /* We are asked not to replace the xattr */
294 err = -EEXIST;
295 goto out_free;
296 }
297
298 inode = iget_xattr(c, le64_to_cpu(xent->inum));
299 if (IS_ERR(inode)) {
300 err = PTR_ERR(inode);
301 goto out_free;
302 }
303
304 err = change_xattr(c, host, inode, value, size);
305 iput(inode);
306
307out_free:
308 up_write(&ubifs_inode(host)->xattr_sem);
309 kfree(xent);
310 return err;
311}
312
313ssize_t ubifs_xattr_get(struct inode *host, const char *name, void *buf,
314 size_t size)
315{
316 struct inode *inode;
317 struct ubifs_info *c = host->i_sb->s_fs_info;
318 struct fscrypt_name nm = { .disk_name = FSTR_INIT((char *)name, strlen(name))};
319 struct ubifs_inode *ui;
320 struct ubifs_dent_node *xent;
321 union ubifs_key key;
322 int err;
323
324 if (fname_len(&nm) > UBIFS_MAX_NLEN)
325 return -ENAMETOOLONG;
326
327 xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
328 if (!xent)
329 return -ENOMEM;
330
331 down_read(&ubifs_inode(host)->xattr_sem);
332 xent_key_init(c, &key, host->i_ino, &nm);
333 err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
334 if (err) {
335 if (err == -ENOENT)
336 err = -ENODATA;
337 goto out_cleanup;
338 }
339
340 inode = iget_xattr(c, le64_to_cpu(xent->inum));
341 if (IS_ERR(inode)) {
342 err = PTR_ERR(inode);
343 goto out_cleanup;
344 }
345
346 ui = ubifs_inode(inode);
347 ubifs_assert(c, inode->i_size == ui->data_len);
348 ubifs_assert(c, ubifs_inode(host)->xattr_size > ui->data_len);
349
350 if (buf) {
351 /* If @buf is %NULL we are supposed to return the length */
352 if (ui->data_len > size) {
353 err = -ERANGE;
354 goto out_iput;
355 }
356
357 memcpy(buf, ui->data, ui->data_len);
358 }
359 err = ui->data_len;
360
361out_iput:
362 iput(inode);
363out_cleanup:
364 up_read(&ubifs_inode(host)->xattr_sem);
365 kfree(xent);
366 return err;
367}
368
369static bool xattr_visible(const char *name)
370{
371 /* File encryption related xattrs are for internal use only */
372 if (strcmp(name, UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT) == 0)
373 return false;
374
375 /* Show trusted namespace only for "power" users */
376 if (strncmp(name, XATTR_TRUSTED_PREFIX,
377 XATTR_TRUSTED_PREFIX_LEN) == 0 && !capable(CAP_SYS_ADMIN))
378 return false;
379
380 return true;
381}
382
383ssize_t ubifs_listxattr(struct dentry *dentry, char *buffer, size_t size)
384{
385 union ubifs_key key;
386 struct inode *host = d_inode(dentry);
387 struct ubifs_info *c = host->i_sb->s_fs_info;
388 struct ubifs_inode *host_ui = ubifs_inode(host);
389 struct ubifs_dent_node *xent, *pxent = NULL;
390 int err, len, written = 0;
391 struct fscrypt_name nm = {0};
392
393 dbg_gen("ino %lu ('%pd'), buffer size %zd", host->i_ino,
394 dentry, size);
395
396 down_read(&host_ui->xattr_sem);
397 len = host_ui->xattr_names + host_ui->xattr_cnt;
398 if (!buffer) {
399 /*
400 * We should return the minimum buffer size which will fit a
401 * null-terminated list of all the extended attribute names.
402 */
403 err = len;
404 goto out_err;
405 }
406
407 if (len > size) {
408 err = -ERANGE;
409 goto out_err;
410 }
411
412 lowest_xent_key(c, &key, host->i_ino);
413 while (1) {
414 xent = ubifs_tnc_next_ent(c, &key, &nm);
415 if (IS_ERR(xent)) {
416 err = PTR_ERR(xent);
417 break;
418 }
419
420 fname_name(&nm) = xent->name;
421 fname_len(&nm) = le16_to_cpu(xent->nlen);
422
423 if (xattr_visible(xent->name)) {
424 memcpy(buffer + written, fname_name(&nm), fname_len(&nm) + 1);
425 written += fname_len(&nm) + 1;
426 }
427
428 kfree(pxent);
429 pxent = xent;
430 key_read(c, &xent->key, &key);
431 }
432 kfree(pxent);
433 up_read(&host_ui->xattr_sem);
434
435 if (err != -ENOENT) {
436 ubifs_err(c, "cannot find next direntry, error %d", err);
437 return err;
438 }
439
440 ubifs_assert(c, written <= size);
441 return written;
442
443out_err:
444 up_read(&host_ui->xattr_sem);
445 return err;
446}
447
448static int remove_xattr(struct ubifs_info *c, struct inode *host,
449 struct inode *inode, const struct fscrypt_name *nm)
450{
451 int err;
452 struct ubifs_inode *host_ui = ubifs_inode(host);
453 struct ubifs_inode *ui = ubifs_inode(inode);
454 struct ubifs_budget_req req = { .dirtied_ino = 2, .mod_dent = 1,
455 .dirtied_ino_d = ALIGN(host_ui->data_len, 8) };
456
457 ubifs_assert(c, ui->data_len == inode->i_size);
458
459 err = ubifs_budget_space(c, &req);
460 if (err)
461 return err;
462
463 mutex_lock(&host_ui->ui_mutex);
464 inode_set_ctime_current(host);
465 host_ui->xattr_cnt -= 1;
466 host_ui->xattr_size -= CALC_DENT_SIZE(fname_len(nm));
467 host_ui->xattr_size -= CALC_XATTR_BYTES(ui->data_len);
468 host_ui->xattr_names -= fname_len(nm);
469
470 err = ubifs_jnl_delete_xattr(c, host, inode, nm);
471 if (err)
472 goto out_cancel;
473 mutex_unlock(&host_ui->ui_mutex);
474
475 ubifs_release_budget(c, &req);
476 return 0;
477
478out_cancel:
479 host_ui->xattr_cnt += 1;
480 host_ui->xattr_size += CALC_DENT_SIZE(fname_len(nm));
481 host_ui->xattr_size += CALC_XATTR_BYTES(ui->data_len);
482 host_ui->xattr_names += fname_len(nm);
483 mutex_unlock(&host_ui->ui_mutex);
484 ubifs_release_budget(c, &req);
485 make_bad_inode(inode);
486 return err;
487}
488
489int ubifs_purge_xattrs(struct inode *host)
490{
491 union ubifs_key key;
492 struct ubifs_info *c = host->i_sb->s_fs_info;
493 struct ubifs_dent_node *xent, *pxent = NULL;
494 struct inode *xino;
495 struct fscrypt_name nm = {0};
496 int err;
497
498 if (ubifs_inode(host)->xattr_cnt <= ubifs_xattr_max_cnt(c))
499 return 0;
500
501 ubifs_warn(c, "inode %lu has too many xattrs, doing a non-atomic deletion",
502 host->i_ino);
503
504 down_write(&ubifs_inode(host)->xattr_sem);
505 lowest_xent_key(c, &key, host->i_ino);
506 while (1) {
507 xent = ubifs_tnc_next_ent(c, &key, &nm);
508 if (IS_ERR(xent)) {
509 err = PTR_ERR(xent);
510 break;
511 }
512
513 fname_name(&nm) = xent->name;
514 fname_len(&nm) = le16_to_cpu(xent->nlen);
515
516 xino = ubifs_iget(c->vfs_sb, le64_to_cpu(xent->inum));
517 if (IS_ERR(xino)) {
518 err = PTR_ERR(xino);
519 ubifs_err(c, "dead directory entry '%s', error %d",
520 xent->name, err);
521 ubifs_ro_mode(c, err);
522 goto out_err;
523 }
524
525 ubifs_assert(c, ubifs_inode(xino)->xattr);
526
527 clear_nlink(xino);
528 err = remove_xattr(c, host, xino, &nm);
529 iput(xino);
530 if (err) {
531 ubifs_err(c, "cannot remove xattr, error %d", err);
532 goto out_err;
533 }
534
535 kfree(pxent);
536 pxent = xent;
537 key_read(c, &xent->key, &key);
538 }
539 kfree(pxent);
540 up_write(&ubifs_inode(host)->xattr_sem);
541
542 if (err != -ENOENT) {
543 ubifs_err(c, "cannot find next direntry, error %d", err);
544 return err;
545 }
546
547 return 0;
548
549out_err:
550 kfree(pxent);
551 kfree(xent);
552 up_write(&ubifs_inode(host)->xattr_sem);
553 return err;
554}
555
556static int ubifs_xattr_remove(struct inode *host, const char *name)
557{
558 struct inode *inode;
559 struct ubifs_info *c = host->i_sb->s_fs_info;
560 struct fscrypt_name nm = { .disk_name = FSTR_INIT((char *)name, strlen(name))};
561 struct ubifs_dent_node *xent;
562 union ubifs_key key;
563 int err;
564
565 ubifs_assert(c, inode_is_locked(host));
566
567 if (fname_len(&nm) > UBIFS_MAX_NLEN)
568 return -ENAMETOOLONG;
569
570 xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
571 if (!xent)
572 return -ENOMEM;
573
574 down_write(&ubifs_inode(host)->xattr_sem);
575 xent_key_init(c, &key, host->i_ino, &nm);
576 err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
577 if (err) {
578 if (err == -ENOENT)
579 err = -ENODATA;
580 goto out_free;
581 }
582
583 inode = iget_xattr(c, le64_to_cpu(xent->inum));
584 if (IS_ERR(inode)) {
585 err = PTR_ERR(inode);
586 goto out_free;
587 }
588
589 ubifs_assert(c, inode->i_nlink == 1);
590 clear_nlink(inode);
591 err = remove_xattr(c, host, inode, &nm);
592 if (err)
593 set_nlink(inode, 1);
594
595 /* If @i_nlink is 0, 'iput()' will delete the inode */
596 iput(inode);
597
598out_free:
599 up_write(&ubifs_inode(host)->xattr_sem);
600 kfree(xent);
601 return err;
602}
603
604#ifdef CONFIG_UBIFS_FS_SECURITY
605static int init_xattrs(struct inode *inode, const struct xattr *xattr_array,
606 void *fs_info)
607{
608 const struct xattr *xattr;
609 char *name;
610 int err = 0;
611
612 for (xattr = xattr_array; xattr->name != NULL; xattr++) {
613 name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
614 strlen(xattr->name) + 1, GFP_NOFS);
615 if (!name) {
616 err = -ENOMEM;
617 break;
618 }
619 strcpy(name, XATTR_SECURITY_PREFIX);
620 strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
621 /*
622 * creating a new inode without holding the inode rwsem,
623 * no need to check whether inode is locked.
624 */
625 err = ubifs_xattr_set(inode, name, xattr->value,
626 xattr->value_len, 0, false);
627 kfree(name);
628 if (err < 0)
629 break;
630 }
631
632 return err;
633}
634
635int ubifs_init_security(struct inode *dentry, struct inode *inode,
636 const struct qstr *qstr)
637{
638 int err;
639
640 err = security_inode_init_security(inode, dentry, qstr,
641 &init_xattrs, NULL);
642 if (err) {
643 struct ubifs_info *c = dentry->i_sb->s_fs_info;
644 ubifs_err(c, "cannot initialize security for inode %lu, error %d",
645 inode->i_ino, err);
646 }
647 return err;
648}
649#endif
650
651static int xattr_get(const struct xattr_handler *handler,
652 struct dentry *dentry, struct inode *inode,
653 const char *name, void *buffer, size_t size)
654{
655 dbg_gen("xattr '%s', ino %lu ('%pd'), buf size %zd", name,
656 inode->i_ino, dentry, size);
657
658 name = xattr_full_name(handler, name);
659 return ubifs_xattr_get(inode, name, buffer, size);
660}
661
662static int xattr_set(const struct xattr_handler *handler,
663 struct mnt_idmap *idmap,
664 struct dentry *dentry, struct inode *inode,
665 const char *name, const void *value,
666 size_t size, int flags)
667{
668 dbg_gen("xattr '%s', host ino %lu ('%pd'), size %zd",
669 name, inode->i_ino, dentry, size);
670
671 name = xattr_full_name(handler, name);
672
673 if (value)
674 return ubifs_xattr_set(inode, name, value, size, flags, true);
675 else
676 return ubifs_xattr_remove(inode, name);
677}
678
679static const struct xattr_handler ubifs_user_xattr_handler = {
680 .prefix = XATTR_USER_PREFIX,
681 .get = xattr_get,
682 .set = xattr_set,
683};
684
685static const struct xattr_handler ubifs_trusted_xattr_handler = {
686 .prefix = XATTR_TRUSTED_PREFIX,
687 .get = xattr_get,
688 .set = xattr_set,
689};
690
691#ifdef CONFIG_UBIFS_FS_SECURITY
692static const struct xattr_handler ubifs_security_xattr_handler = {
693 .prefix = XATTR_SECURITY_PREFIX,
694 .get = xattr_get,
695 .set = xattr_set,
696};
697#endif
698
699const struct xattr_handler * const ubifs_xattr_handlers[] = {
700 &ubifs_user_xattr_handler,
701 &ubifs_trusted_xattr_handler,
702#ifdef CONFIG_UBIFS_FS_SECURITY
703 &ubifs_security_xattr_handler,
704#endif
705 NULL
706};