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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#include <linux/posix_acl_xattr.h>
63
64/*
65 * Limit the number of extended attributes per inode so that the total size
66 * (@xattr_size) is guaranteeded to fit in an 'unsigned int'.
67 */
68#define MAX_XATTRS_PER_INODE 65535
69
70/*
71 * Extended attribute type constants.
72 *
73 * USER_XATTR: user extended attribute ("user.*")
74 * TRUSTED_XATTR: trusted extended attribute ("trusted.*)
75 * SECURITY_XATTR: security extended attribute ("security.*")
76 */
77enum {
78 USER_XATTR,
79 TRUSTED_XATTR,
80 SECURITY_XATTR,
81};
82
83static const struct inode_operations empty_iops;
84static const struct file_operations empty_fops;
85
86/**
87 * create_xattr - create an extended attribute.
88 * @c: UBIFS file-system description object
89 * @host: host inode
90 * @nm: extended attribute name
91 * @value: extended attribute value
92 * @size: size of extended attribute value
93 *
94 * This is a helper function which creates an extended attribute of name @nm
95 * and value @value for inode @host. The host inode is also updated on flash
96 * because the ctime and extended attribute accounting data changes. This
97 * function returns zero in case of success and a negative error code in case
98 * of failure.
99 */
100static int create_xattr(struct ubifs_info *c, struct inode *host,
101 const struct qstr *nm, const void *value, int size)
102{
103 int err;
104 struct inode *inode;
105 struct ubifs_inode *ui, *host_ui = ubifs_inode(host);
106 struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1,
107 .new_ino_d = ALIGN(size, 8), .dirtied_ino = 1,
108 .dirtied_ino_d = ALIGN(host_ui->data_len, 8) };
109
110 if (host_ui->xattr_cnt >= MAX_XATTRS_PER_INODE)
111 return -ENOSPC;
112 /*
113 * Linux limits the maximum size of the extended attribute names list
114 * to %XATTR_LIST_MAX. This means we should not allow creating more
115 * extended attributes if the name list becomes larger. This limitation
116 * is artificial for UBIFS, though.
117 */
118 if (host_ui->xattr_names + host_ui->xattr_cnt +
119 nm->len + 1 > XATTR_LIST_MAX)
120 return -ENOSPC;
121
122 err = ubifs_budget_space(c, &req);
123 if (err)
124 return err;
125
126 inode = ubifs_new_inode(c, host, S_IFREG | S_IRWXUGO);
127 if (IS_ERR(inode)) {
128 err = PTR_ERR(inode);
129 goto out_budg;
130 }
131
132 /* Re-define all operations to be "nothing" */
133 inode->i_mapping->a_ops = &empty_aops;
134 inode->i_op = &empty_iops;
135 inode->i_fop = &empty_fops;
136
137 inode->i_flags |= S_SYNC | S_NOATIME | S_NOCMTIME | S_NOQUOTA;
138 ui = ubifs_inode(inode);
139 ui->xattr = 1;
140 ui->flags |= UBIFS_XATTR_FL;
141 ui->data = kmemdup(value, size, GFP_NOFS);
142 if (!ui->data) {
143 err = -ENOMEM;
144 goto out_free;
145 }
146 inode->i_size = ui->ui_size = size;
147 ui->data_len = size;
148
149 mutex_lock(&host_ui->ui_mutex);
150 host->i_ctime = ubifs_current_time(host);
151 host_ui->xattr_cnt += 1;
152 host_ui->xattr_size += CALC_DENT_SIZE(nm->len);
153 host_ui->xattr_size += CALC_XATTR_BYTES(size);
154 host_ui->xattr_names += nm->len;
155
156 err = ubifs_jnl_update(c, host, nm, inode, 0, 1);
157 if (err)
158 goto out_cancel;
159 mutex_unlock(&host_ui->ui_mutex);
160
161 ubifs_release_budget(c, &req);
162 insert_inode_hash(inode);
163 iput(inode);
164 return 0;
165
166out_cancel:
167 host_ui->xattr_cnt -= 1;
168 host_ui->xattr_size -= CALC_DENT_SIZE(nm->len);
169 host_ui->xattr_size -= CALC_XATTR_BYTES(size);
170 mutex_unlock(&host_ui->ui_mutex);
171out_free:
172 make_bad_inode(inode);
173 iput(inode);
174out_budg:
175 ubifs_release_budget(c, &req);
176 return err;
177}
178
179/**
180 * change_xattr - change an extended attribute.
181 * @c: UBIFS file-system description object
182 * @host: host inode
183 * @inode: extended attribute inode
184 * @value: extended attribute value
185 * @size: size of extended attribute value
186 *
187 * This helper function changes the value of extended attribute @inode with new
188 * data from @value. Returns zero in case of success and a negative error code
189 * in case of failure.
190 */
191static int change_xattr(struct ubifs_info *c, struct inode *host,
192 struct inode *inode, const void *value, int size)
193{
194 int err;
195 struct ubifs_inode *host_ui = ubifs_inode(host);
196 struct ubifs_inode *ui = ubifs_inode(inode);
197 struct ubifs_budget_req req = { .dirtied_ino = 2,
198 .dirtied_ino_d = ALIGN(size, 8) + ALIGN(host_ui->data_len, 8) };
199
200 ubifs_assert(ui->data_len == inode->i_size);
201 err = ubifs_budget_space(c, &req);
202 if (err)
203 return err;
204
205 kfree(ui->data);
206 ui->data = kmemdup(value, size, GFP_NOFS);
207 if (!ui->data) {
208 err = -ENOMEM;
209 goto out_free;
210 }
211 inode->i_size = ui->ui_size = size;
212 ui->data_len = size;
213
214 mutex_lock(&host_ui->ui_mutex);
215 host->i_ctime = ubifs_current_time(host);
216 host_ui->xattr_size -= CALC_XATTR_BYTES(ui->data_len);
217 host_ui->xattr_size += CALC_XATTR_BYTES(size);
218
219 /*
220 * It is important to write the host inode after the xattr inode
221 * because if the host inode gets synchronized (via 'fsync()'), then
222 * the extended attribute inode gets synchronized, because it goes
223 * before the host inode in the write-buffer.
224 */
225 err = ubifs_jnl_change_xattr(c, inode, host);
226 if (err)
227 goto out_cancel;
228 mutex_unlock(&host_ui->ui_mutex);
229
230 ubifs_release_budget(c, &req);
231 return 0;
232
233out_cancel:
234 host_ui->xattr_size -= CALC_XATTR_BYTES(size);
235 host_ui->xattr_size += CALC_XATTR_BYTES(ui->data_len);
236 mutex_unlock(&host_ui->ui_mutex);
237 make_bad_inode(inode);
238out_free:
239 ubifs_release_budget(c, &req);
240 return err;
241}
242
243/**
244 * check_namespace - check extended attribute name-space.
245 * @nm: extended attribute name
246 *
247 * This function makes sure the extended attribute name belongs to one of the
248 * supported extended attribute name-spaces. Returns name-space index in case
249 * of success and a negative error code in case of failure.
250 */
251static int check_namespace(const struct qstr *nm)
252{
253 int type;
254
255 if (nm->len > UBIFS_MAX_NLEN)
256 return -ENAMETOOLONG;
257
258 if (!strncmp(nm->name, XATTR_TRUSTED_PREFIX,
259 XATTR_TRUSTED_PREFIX_LEN)) {
260 if (nm->name[sizeof(XATTR_TRUSTED_PREFIX) - 1] == '\0')
261 return -EINVAL;
262 type = TRUSTED_XATTR;
263 } else if (!strncmp(nm->name, XATTR_USER_PREFIX,
264 XATTR_USER_PREFIX_LEN)) {
265 if (nm->name[XATTR_USER_PREFIX_LEN] == '\0')
266 return -EINVAL;
267 type = USER_XATTR;
268 } else if (!strncmp(nm->name, XATTR_SECURITY_PREFIX,
269 XATTR_SECURITY_PREFIX_LEN)) {
270 if (nm->name[sizeof(XATTR_SECURITY_PREFIX) - 1] == '\0')
271 return -EINVAL;
272 type = SECURITY_XATTR;
273 } else
274 return -EOPNOTSUPP;
275
276 return type;
277}
278
279static struct inode *iget_xattr(struct ubifs_info *c, ino_t inum)
280{
281 struct inode *inode;
282
283 inode = ubifs_iget(c->vfs_sb, inum);
284 if (IS_ERR(inode)) {
285 ubifs_err("dead extended attribute entry, error %d",
286 (int)PTR_ERR(inode));
287 return inode;
288 }
289 if (ubifs_inode(inode)->xattr)
290 return inode;
291 ubifs_err("corrupt extended attribute entry");
292 iput(inode);
293 return ERR_PTR(-EINVAL);
294}
295
296int ubifs_setxattr(struct dentry *dentry, const char *name,
297 const void *value, size_t size, int flags)
298{
299 struct inode *inode, *host = dentry->d_inode;
300 struct ubifs_info *c = host->i_sb->s_fs_info;
301 struct qstr nm = QSTR_INIT(name, strlen(name));
302 struct ubifs_dent_node *xent;
303 union ubifs_key key;
304 int err, type;
305
306 dbg_gen("xattr '%s', host ino %lu ('%.*s'), size %zd", name,
307 host->i_ino, dentry->d_name.len, dentry->d_name.name, size);
308 ubifs_assert(mutex_is_locked(&host->i_mutex));
309
310 if (size > UBIFS_MAX_INO_DATA)
311 return -ERANGE;
312
313 type = check_namespace(&nm);
314 if (type < 0)
315 return type;
316
317 xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
318 if (!xent)
319 return -ENOMEM;
320
321 /*
322 * The extended attribute entries are stored in LNC, so multiple
323 * look-ups do not involve reading the flash.
324 */
325 xent_key_init(c, &key, host->i_ino, &nm);
326 err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
327 if (err) {
328 if (err != -ENOENT)
329 goto out_free;
330
331 if (flags & XATTR_REPLACE)
332 /* We are asked not to create the xattr */
333 err = -ENODATA;
334 else
335 err = create_xattr(c, host, &nm, value, size);
336 goto out_free;
337 }
338
339 if (flags & XATTR_CREATE) {
340 /* We are asked not to replace the xattr */
341 err = -EEXIST;
342 goto out_free;
343 }
344
345 inode = iget_xattr(c, le64_to_cpu(xent->inum));
346 if (IS_ERR(inode)) {
347 err = PTR_ERR(inode);
348 goto out_free;
349 }
350
351 err = change_xattr(c, host, inode, value, size);
352 iput(inode);
353
354out_free:
355 kfree(xent);
356 return err;
357}
358
359ssize_t ubifs_getxattr(struct dentry *dentry, const char *name, void *buf,
360 size_t size)
361{
362 struct inode *inode, *host = dentry->d_inode;
363 struct ubifs_info *c = host->i_sb->s_fs_info;
364 struct qstr nm = QSTR_INIT(name, strlen(name));
365 struct ubifs_inode *ui;
366 struct ubifs_dent_node *xent;
367 union ubifs_key key;
368 int err;
369
370 dbg_gen("xattr '%s', ino %lu ('%.*s'), buf size %zd", name,
371 host->i_ino, dentry->d_name.len, dentry->d_name.name, size);
372
373 err = check_namespace(&nm);
374 if (err < 0)
375 return err;
376
377 xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
378 if (!xent)
379 return -ENOMEM;
380
381 xent_key_init(c, &key, host->i_ino, &nm);
382 err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
383 if (err) {
384 if (err == -ENOENT)
385 err = -ENODATA;
386 goto out_unlock;
387 }
388
389 inode = iget_xattr(c, le64_to_cpu(xent->inum));
390 if (IS_ERR(inode)) {
391 err = PTR_ERR(inode);
392 goto out_unlock;
393 }
394
395 ui = ubifs_inode(inode);
396 ubifs_assert(inode->i_size == ui->data_len);
397 ubifs_assert(ubifs_inode(host)->xattr_size > ui->data_len);
398
399 if (buf) {
400 /* If @buf is %NULL we are supposed to return the length */
401 if (ui->data_len > size) {
402 ubifs_err("buffer size %zd, xattr len %d",
403 size, ui->data_len);
404 err = -ERANGE;
405 goto out_iput;
406 }
407
408 memcpy(buf, ui->data, ui->data_len);
409 }
410 err = ui->data_len;
411
412out_iput:
413 iput(inode);
414out_unlock:
415 kfree(xent);
416 return err;
417}
418
419ssize_t ubifs_listxattr(struct dentry *dentry, char *buffer, size_t size)
420{
421 union ubifs_key key;
422 struct inode *host = dentry->d_inode;
423 struct ubifs_info *c = host->i_sb->s_fs_info;
424 struct ubifs_inode *host_ui = ubifs_inode(host);
425 struct ubifs_dent_node *xent, *pxent = NULL;
426 int err, len, written = 0;
427 struct qstr nm = { .name = NULL };
428
429 dbg_gen("ino %lu ('%.*s'), buffer size %zd", host->i_ino,
430 dentry->d_name.len, dentry->d_name.name, size);
431
432 len = host_ui->xattr_names + host_ui->xattr_cnt;
433 if (!buffer)
434 /*
435 * We should return the minimum buffer size which will fit a
436 * null-terminated list of all the extended attribute names.
437 */
438 return len;
439
440 if (len > size)
441 return -ERANGE;
442
443 lowest_xent_key(c, &key, host->i_ino);
444 while (1) {
445 int type;
446
447 xent = ubifs_tnc_next_ent(c, &key, &nm);
448 if (IS_ERR(xent)) {
449 err = PTR_ERR(xent);
450 break;
451 }
452
453 nm.name = xent->name;
454 nm.len = le16_to_cpu(xent->nlen);
455
456 type = check_namespace(&nm);
457 if (unlikely(type < 0)) {
458 err = type;
459 break;
460 }
461
462 /* Show trusted namespace only for "power" users */
463 if (type != TRUSTED_XATTR || capable(CAP_SYS_ADMIN)) {
464 memcpy(buffer + written, nm.name, nm.len + 1);
465 written += nm.len + 1;
466 }
467
468 kfree(pxent);
469 pxent = xent;
470 key_read(c, &xent->key, &key);
471 }
472
473 kfree(pxent);
474 if (err != -ENOENT) {
475 ubifs_err("cannot find next direntry, error %d", err);
476 return err;
477 }
478
479 ubifs_assert(written <= size);
480 return written;
481}
482
483static int remove_xattr(struct ubifs_info *c, struct inode *host,
484 struct inode *inode, const struct qstr *nm)
485{
486 int err;
487 struct ubifs_inode *host_ui = ubifs_inode(host);
488 struct ubifs_inode *ui = ubifs_inode(inode);
489 struct ubifs_budget_req req = { .dirtied_ino = 2, .mod_dent = 1,
490 .dirtied_ino_d = ALIGN(host_ui->data_len, 8) };
491
492 ubifs_assert(ui->data_len == inode->i_size);
493
494 err = ubifs_budget_space(c, &req);
495 if (err)
496 return err;
497
498 mutex_lock(&host_ui->ui_mutex);
499 host->i_ctime = ubifs_current_time(host);
500 host_ui->xattr_cnt -= 1;
501 host_ui->xattr_size -= CALC_DENT_SIZE(nm->len);
502 host_ui->xattr_size -= CALC_XATTR_BYTES(ui->data_len);
503 host_ui->xattr_names -= nm->len;
504
505 err = ubifs_jnl_delete_xattr(c, host, inode, nm);
506 if (err)
507 goto out_cancel;
508 mutex_unlock(&host_ui->ui_mutex);
509
510 ubifs_release_budget(c, &req);
511 return 0;
512
513out_cancel:
514 host_ui->xattr_cnt += 1;
515 host_ui->xattr_size += CALC_DENT_SIZE(nm->len);
516 host_ui->xattr_size += CALC_XATTR_BYTES(ui->data_len);
517 mutex_unlock(&host_ui->ui_mutex);
518 ubifs_release_budget(c, &req);
519 make_bad_inode(inode);
520 return err;
521}
522
523int ubifs_removexattr(struct dentry *dentry, const char *name)
524{
525 struct inode *inode, *host = dentry->d_inode;
526 struct ubifs_info *c = host->i_sb->s_fs_info;
527 struct qstr nm = QSTR_INIT(name, strlen(name));
528 struct ubifs_dent_node *xent;
529 union ubifs_key key;
530 int err;
531
532 dbg_gen("xattr '%s', ino %lu ('%.*s')", name,
533 host->i_ino, dentry->d_name.len, dentry->d_name.name);
534 ubifs_assert(mutex_is_locked(&host->i_mutex));
535
536 err = check_namespace(&nm);
537 if (err < 0)
538 return err;
539
540 xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
541 if (!xent)
542 return -ENOMEM;
543
544 xent_key_init(c, &key, host->i_ino, &nm);
545 err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
546 if (err) {
547 if (err == -ENOENT)
548 err = -ENODATA;
549 goto out_free;
550 }
551
552 inode = iget_xattr(c, le64_to_cpu(xent->inum));
553 if (IS_ERR(inode)) {
554 err = PTR_ERR(inode);
555 goto out_free;
556 }
557
558 ubifs_assert(inode->i_nlink == 1);
559 clear_nlink(inode);
560 err = remove_xattr(c, host, inode, &nm);
561 if (err)
562 set_nlink(inode, 1);
563
564 /* If @i_nlink is 0, 'iput()' will delete the inode */
565 iput(inode);
566
567out_free:
568 kfree(xent);
569 return err;
570}
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 fscrypt_name *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 + fname_len(nm) + 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 = current_time(host);
156 host_ui->xattr_cnt += 1;
157 host_ui->xattr_size += CALC_DENT_SIZE(fname_len(nm));
158 host_ui->xattr_size += CALC_XATTR_BYTES(size);
159 host_ui->xattr_names += fname_len(nm);
160
161 /*
162 * We handle UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT here because we
163 * have to set the UBIFS_CRYPT_FL flag on the host inode.
164 * To avoid multiple updates of the same inode in the same operation,
165 * let's do it here.
166 */
167 if (strcmp(fname_name(nm), UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT) == 0)
168 host_ui->flags |= UBIFS_CRYPT_FL;
169
170 err = ubifs_jnl_update(c, host, nm, inode, 0, 1);
171 if (err)
172 goto out_cancel;
173 ubifs_set_inode_flags(host);
174 mutex_unlock(&host_ui->ui_mutex);
175
176 ubifs_release_budget(c, &req);
177 insert_inode_hash(inode);
178 iput(inode);
179 return 0;
180
181out_cancel:
182 host_ui->xattr_cnt -= 1;
183 host_ui->xattr_size -= CALC_DENT_SIZE(fname_len(nm));
184 host_ui->xattr_size -= CALC_XATTR_BYTES(size);
185 host_ui->xattr_names -= fname_len(nm);
186 host_ui->flags &= ~UBIFS_CRYPT_FL;
187 mutex_unlock(&host_ui->ui_mutex);
188out_free:
189 make_bad_inode(inode);
190 iput(inode);
191out_budg:
192 ubifs_release_budget(c, &req);
193 return err;
194}
195
196/**
197 * change_xattr - change an extended attribute.
198 * @c: UBIFS file-system description object
199 * @host: host inode
200 * @inode: extended attribute inode
201 * @value: extended attribute value
202 * @size: size of extended attribute value
203 *
204 * This helper function changes the value of extended attribute @inode with new
205 * data from @value. Returns zero in case of success and a negative error code
206 * in case of failure.
207 */
208static int change_xattr(struct ubifs_info *c, struct inode *host,
209 struct inode *inode, const void *value, int size)
210{
211 int err;
212 struct ubifs_inode *host_ui = ubifs_inode(host);
213 struct ubifs_inode *ui = ubifs_inode(inode);
214 void *buf = NULL;
215 int old_size;
216 struct ubifs_budget_req req = { .dirtied_ino = 2,
217 .dirtied_ino_d = ALIGN(size, 8) + ALIGN(host_ui->data_len, 8) };
218
219 ubifs_assert(ui->data_len == inode->i_size);
220 err = ubifs_budget_space(c, &req);
221 if (err)
222 return err;
223
224 buf = kmemdup(value, size, GFP_NOFS);
225 if (!buf) {
226 err = -ENOMEM;
227 goto out_free;
228 }
229 mutex_lock(&ui->ui_mutex);
230 kfree(ui->data);
231 ui->data = buf;
232 inode->i_size = ui->ui_size = size;
233 old_size = ui->data_len;
234 ui->data_len = size;
235 mutex_unlock(&ui->ui_mutex);
236
237 mutex_lock(&host_ui->ui_mutex);
238 host->i_ctime = current_time(host);
239 host_ui->xattr_size -= CALC_XATTR_BYTES(old_size);
240 host_ui->xattr_size += CALC_XATTR_BYTES(size);
241
242 /*
243 * It is important to write the host inode after the xattr inode
244 * because if the host inode gets synchronized (via 'fsync()'), then
245 * the extended attribute inode gets synchronized, because it goes
246 * before the host inode in the write-buffer.
247 */
248 err = ubifs_jnl_change_xattr(c, inode, host);
249 if (err)
250 goto out_cancel;
251 mutex_unlock(&host_ui->ui_mutex);
252
253 ubifs_release_budget(c, &req);
254 return 0;
255
256out_cancel:
257 host_ui->xattr_size -= CALC_XATTR_BYTES(size);
258 host_ui->xattr_size += CALC_XATTR_BYTES(old_size);
259 mutex_unlock(&host_ui->ui_mutex);
260 make_bad_inode(inode);
261out_free:
262 ubifs_release_budget(c, &req);
263 return err;
264}
265
266static struct inode *iget_xattr(struct ubifs_info *c, ino_t inum)
267{
268 struct inode *inode;
269
270 inode = ubifs_iget(c->vfs_sb, inum);
271 if (IS_ERR(inode)) {
272 ubifs_err(c, "dead extended attribute entry, error %d",
273 (int)PTR_ERR(inode));
274 return inode;
275 }
276 if (ubifs_inode(inode)->xattr)
277 return inode;
278 ubifs_err(c, "corrupt extended attribute entry");
279 iput(inode);
280 return ERR_PTR(-EINVAL);
281}
282
283int ubifs_xattr_set(struct inode *host, const char *name, const void *value,
284 size_t size, int flags, bool check_lock)
285{
286 struct inode *inode;
287 struct ubifs_info *c = host->i_sb->s_fs_info;
288 struct fscrypt_name nm = { .disk_name = FSTR_INIT((char *)name, strlen(name))};
289 struct ubifs_dent_node *xent;
290 union ubifs_key key;
291 int err;
292
293 if (check_lock)
294 ubifs_assert(inode_is_locked(host));
295
296 if (size > UBIFS_MAX_INO_DATA)
297 return -ERANGE;
298
299 if (fname_len(&nm) > UBIFS_MAX_NLEN)
300 return -ENAMETOOLONG;
301
302 xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
303 if (!xent)
304 return -ENOMEM;
305
306 /*
307 * The extended attribute entries are stored in LNC, so multiple
308 * look-ups do not involve reading the flash.
309 */
310 xent_key_init(c, &key, host->i_ino, &nm);
311 err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
312 if (err) {
313 if (err != -ENOENT)
314 goto out_free;
315
316 if (flags & XATTR_REPLACE)
317 /* We are asked not to create the xattr */
318 err = -ENODATA;
319 else
320 err = create_xattr(c, host, &nm, value, size);
321 goto out_free;
322 }
323
324 if (flags & XATTR_CREATE) {
325 /* We are asked not to replace the xattr */
326 err = -EEXIST;
327 goto out_free;
328 }
329
330 inode = iget_xattr(c, le64_to_cpu(xent->inum));
331 if (IS_ERR(inode)) {
332 err = PTR_ERR(inode);
333 goto out_free;
334 }
335
336 err = change_xattr(c, host, inode, value, size);
337 iput(inode);
338
339out_free:
340 kfree(xent);
341 return err;
342}
343
344ssize_t ubifs_xattr_get(struct inode *host, const char *name, void *buf,
345 size_t size)
346{
347 struct inode *inode;
348 struct ubifs_info *c = host->i_sb->s_fs_info;
349 struct fscrypt_name nm = { .disk_name = FSTR_INIT((char *)name, strlen(name))};
350 struct ubifs_inode *ui;
351 struct ubifs_dent_node *xent;
352 union ubifs_key key;
353 int err;
354
355 if (fname_len(&nm) > UBIFS_MAX_NLEN)
356 return -ENAMETOOLONG;
357
358 xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
359 if (!xent)
360 return -ENOMEM;
361
362 xent_key_init(c, &key, host->i_ino, &nm);
363 err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
364 if (err) {
365 if (err == -ENOENT)
366 err = -ENODATA;
367 goto out_unlock;
368 }
369
370 inode = iget_xattr(c, le64_to_cpu(xent->inum));
371 if (IS_ERR(inode)) {
372 err = PTR_ERR(inode);
373 goto out_unlock;
374 }
375
376 ui = ubifs_inode(inode);
377 ubifs_assert(inode->i_size == ui->data_len);
378 ubifs_assert(ubifs_inode(host)->xattr_size > ui->data_len);
379
380 mutex_lock(&ui->ui_mutex);
381 if (buf) {
382 /* If @buf is %NULL we are supposed to return the length */
383 if (ui->data_len > size) {
384 err = -ERANGE;
385 goto out_iput;
386 }
387
388 memcpy(buf, ui->data, ui->data_len);
389 }
390 err = ui->data_len;
391
392out_iput:
393 mutex_unlock(&ui->ui_mutex);
394 iput(inode);
395out_unlock:
396 kfree(xent);
397 return err;
398}
399
400static bool xattr_visible(const char *name)
401{
402 /* File encryption related xattrs are for internal use only */
403 if (strcmp(name, UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT) == 0)
404 return false;
405
406 /* Show trusted namespace only for "power" users */
407 if (strncmp(name, XATTR_TRUSTED_PREFIX,
408 XATTR_TRUSTED_PREFIX_LEN) == 0 && !capable(CAP_SYS_ADMIN))
409 return false;
410
411 return true;
412}
413
414ssize_t ubifs_listxattr(struct dentry *dentry, char *buffer, size_t size)
415{
416 union ubifs_key key;
417 struct inode *host = d_inode(dentry);
418 struct ubifs_info *c = host->i_sb->s_fs_info;
419 struct ubifs_inode *host_ui = ubifs_inode(host);
420 struct ubifs_dent_node *xent, *pxent = NULL;
421 int err, len, written = 0;
422 struct fscrypt_name nm = {0};
423
424 dbg_gen("ino %lu ('%pd'), buffer size %zd", host->i_ino,
425 dentry, size);
426
427 len = host_ui->xattr_names + host_ui->xattr_cnt;
428 if (!buffer)
429 /*
430 * We should return the minimum buffer size which will fit a
431 * null-terminated list of all the extended attribute names.
432 */
433 return len;
434
435 if (len > size)
436 return -ERANGE;
437
438 lowest_xent_key(c, &key, host->i_ino);
439 while (1) {
440 xent = ubifs_tnc_next_ent(c, &key, &nm);
441 if (IS_ERR(xent)) {
442 err = PTR_ERR(xent);
443 break;
444 }
445
446 fname_name(&nm) = xent->name;
447 fname_len(&nm) = le16_to_cpu(xent->nlen);
448
449 if (xattr_visible(xent->name)) {
450 memcpy(buffer + written, fname_name(&nm), fname_len(&nm) + 1);
451 written += fname_len(&nm) + 1;
452 }
453
454 kfree(pxent);
455 pxent = xent;
456 key_read(c, &xent->key, &key);
457 }
458
459 kfree(pxent);
460 if (err != -ENOENT) {
461 ubifs_err(c, "cannot find next direntry, error %d", err);
462 return err;
463 }
464
465 ubifs_assert(written <= size);
466 return written;
467}
468
469static int remove_xattr(struct ubifs_info *c, struct inode *host,
470 struct inode *inode, const struct fscrypt_name *nm)
471{
472 int err;
473 struct ubifs_inode *host_ui = ubifs_inode(host);
474 struct ubifs_inode *ui = ubifs_inode(inode);
475 struct ubifs_budget_req req = { .dirtied_ino = 2, .mod_dent = 1,
476 .dirtied_ino_d = ALIGN(host_ui->data_len, 8) };
477
478 ubifs_assert(ui->data_len == inode->i_size);
479
480 err = ubifs_budget_space(c, &req);
481 if (err)
482 return err;
483
484 mutex_lock(&host_ui->ui_mutex);
485 host->i_ctime = current_time(host);
486 host_ui->xattr_cnt -= 1;
487 host_ui->xattr_size -= CALC_DENT_SIZE(fname_len(nm));
488 host_ui->xattr_size -= CALC_XATTR_BYTES(ui->data_len);
489 host_ui->xattr_names -= fname_len(nm);
490
491 err = ubifs_jnl_delete_xattr(c, host, inode, nm);
492 if (err)
493 goto out_cancel;
494 mutex_unlock(&host_ui->ui_mutex);
495
496 ubifs_release_budget(c, &req);
497 return 0;
498
499out_cancel:
500 host_ui->xattr_cnt += 1;
501 host_ui->xattr_size += CALC_DENT_SIZE(fname_len(nm));
502 host_ui->xattr_size += CALC_XATTR_BYTES(ui->data_len);
503 host_ui->xattr_names += fname_len(nm);
504 mutex_unlock(&host_ui->ui_mutex);
505 ubifs_release_budget(c, &req);
506 make_bad_inode(inode);
507 return err;
508}
509
510/**
511 * ubifs_evict_xattr_inode - Evict an xattr inode.
512 * @c: UBIFS file-system description object
513 * @xattr_inum: xattr inode number
514 *
515 * When an inode that hosts xattrs is being removed we have to make sure
516 * that cached inodes of the xattrs also get removed from the inode cache
517 * otherwise we'd waste memory. This function looks up an inode from the
518 * inode cache and clears the link counter such that iput() will evict
519 * the inode.
520 */
521void ubifs_evict_xattr_inode(struct ubifs_info *c, ino_t xattr_inum)
522{
523 struct inode *inode;
524
525 inode = ilookup(c->vfs_sb, xattr_inum);
526 if (inode) {
527 clear_nlink(inode);
528 iput(inode);
529 }
530}
531
532static int ubifs_xattr_remove(struct inode *host, const char *name)
533{
534 struct inode *inode;
535 struct ubifs_info *c = host->i_sb->s_fs_info;
536 struct fscrypt_name nm = { .disk_name = FSTR_INIT((char *)name, strlen(name))};
537 struct ubifs_dent_node *xent;
538 union ubifs_key key;
539 int err;
540
541 ubifs_assert(inode_is_locked(host));
542
543 if (fname_len(&nm) > UBIFS_MAX_NLEN)
544 return -ENAMETOOLONG;
545
546 xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
547 if (!xent)
548 return -ENOMEM;
549
550 xent_key_init(c, &key, host->i_ino, &nm);
551 err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
552 if (err) {
553 if (err == -ENOENT)
554 err = -ENODATA;
555 goto out_free;
556 }
557
558 inode = iget_xattr(c, le64_to_cpu(xent->inum));
559 if (IS_ERR(inode)) {
560 err = PTR_ERR(inode);
561 goto out_free;
562 }
563
564 ubifs_assert(inode->i_nlink == 1);
565 clear_nlink(inode);
566 err = remove_xattr(c, host, inode, &nm);
567 if (err)
568 set_nlink(inode, 1);
569
570 /* If @i_nlink is 0, 'iput()' will delete the inode */
571 iput(inode);
572
573out_free:
574 kfree(xent);
575 return err;
576}
577
578#ifdef CONFIG_UBIFS_FS_SECURITY
579static int init_xattrs(struct inode *inode, const struct xattr *xattr_array,
580 void *fs_info)
581{
582 const struct xattr *xattr;
583 char *name;
584 int err = 0;
585
586 for (xattr = xattr_array; xattr->name != NULL; xattr++) {
587 name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
588 strlen(xattr->name) + 1, GFP_NOFS);
589 if (!name) {
590 err = -ENOMEM;
591 break;
592 }
593 strcpy(name, XATTR_SECURITY_PREFIX);
594 strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
595 /*
596 * creating a new inode without holding the inode rwsem,
597 * no need to check whether inode is locked.
598 */
599 err = ubifs_xattr_set(inode, name, xattr->value,
600 xattr->value_len, 0, false);
601 kfree(name);
602 if (err < 0)
603 break;
604 }
605
606 return err;
607}
608
609int ubifs_init_security(struct inode *dentry, struct inode *inode,
610 const struct qstr *qstr)
611{
612 int err;
613
614 err = security_inode_init_security(inode, dentry, qstr,
615 &init_xattrs, 0);
616 if (err) {
617 struct ubifs_info *c = dentry->i_sb->s_fs_info;
618 ubifs_err(c, "cannot initialize security for inode %lu, error %d",
619 inode->i_ino, err);
620 }
621 return err;
622}
623#endif
624
625static int xattr_get(const struct xattr_handler *handler,
626 struct dentry *dentry, struct inode *inode,
627 const char *name, void *buffer, size_t size)
628{
629 dbg_gen("xattr '%s', ino %lu ('%pd'), buf size %zd", name,
630 inode->i_ino, dentry, size);
631
632 name = xattr_full_name(handler, name);
633 return ubifs_xattr_get(inode, name, buffer, size);
634}
635
636static int xattr_set(const struct xattr_handler *handler,
637 struct dentry *dentry, struct inode *inode,
638 const char *name, const void *value,
639 size_t size, int flags)
640{
641 dbg_gen("xattr '%s', host ino %lu ('%pd'), size %zd",
642 name, inode->i_ino, dentry, size);
643
644 name = xattr_full_name(handler, name);
645
646 if (value)
647 return ubifs_xattr_set(inode, name, value, size, flags, true);
648 else
649 return ubifs_xattr_remove(inode, name);
650}
651
652static const struct xattr_handler ubifs_user_xattr_handler = {
653 .prefix = XATTR_USER_PREFIX,
654 .get = xattr_get,
655 .set = xattr_set,
656};
657
658static const struct xattr_handler ubifs_trusted_xattr_handler = {
659 .prefix = XATTR_TRUSTED_PREFIX,
660 .get = xattr_get,
661 .set = xattr_set,
662};
663
664#ifdef CONFIG_UBIFS_FS_SECURITY
665static const struct xattr_handler ubifs_security_xattr_handler = {
666 .prefix = XATTR_SECURITY_PREFIX,
667 .get = xattr_get,
668 .set = xattr_set,
669};
670#endif
671
672const struct xattr_handler *ubifs_xattr_handlers[] = {
673 &ubifs_user_xattr_handler,
674 &ubifs_trusted_xattr_handler,
675#ifdef CONFIG_UBIFS_FS_SECURITY
676 &ubifs_security_xattr_handler,
677#endif
678 NULL
679};