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  */
76 enum {
77 	USER_XATTR,
78 	TRUSTED_XATTR,
79 	SECURITY_XATTR,
80 };
81 
82 static const struct inode_operations empty_iops;
83 static 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  */
create_xattr(struct ubifs_info * c,struct inode * host,const struct fscrypt_name * nm,const void * value,int size)99 static 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;
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 
181 out_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);
188 out_free:
189 	make_bad_inode(inode);
190 	iput(inode);
191 out_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  */
change_xattr(struct ubifs_info * c,struct inode * host,struct inode * inode,const void * value,int size)208 static 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(c, 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 
256 out_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);
261 out_free:
262 	ubifs_release_budget(c, &req);
263 	return err;
264 }
265 
iget_xattr(struct ubifs_info * c,ino_t inum)266 static 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 
ubifs_xattr_set(struct inode * host,const char * name,const void * value,size_t size,int flags,bool check_lock)283 int 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(c, 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 
339 out_free:
340 	kfree(xent);
341 	return err;
342 }
343 
ubifs_xattr_get(struct inode * host,const char * name,void * buf,size_t size)344 ssize_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(c, inode->i_size == ui->data_len);
378 	ubifs_assert(c, 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 
392 out_iput:
393 	mutex_unlock(&ui->ui_mutex);
394 	iput(inode);
395 out_unlock:
396 	kfree(xent);
397 	return err;
398 }
399 
xattr_visible(const char * name)400 static 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 
ubifs_listxattr(struct dentry * dentry,char * buffer,size_t size)414 ssize_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(c, written <= size);
466 	return written;
467 }
468 
remove_xattr(struct ubifs_info * c,struct inode * host,struct inode * inode,const struct fscrypt_name * nm)469 static 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(c, 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 
499 out_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  */
ubifs_evict_xattr_inode(struct ubifs_info * c,ino_t xattr_inum)521 void 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 
ubifs_xattr_remove(struct inode * host,const char * name)532 static 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(c, 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(c, 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 
573 out_free:
574 	kfree(xent);
575 	return err;
576 }
577 
578 #ifdef CONFIG_UBIFS_FS_SECURITY
init_xattrs(struct inode * inode,const struct xattr * xattr_array,void * fs_info)579 static 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 
ubifs_init_security(struct inode * dentry,struct inode * inode,const struct qstr * qstr)609 int 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 
xattr_get(const struct xattr_handler * handler,struct dentry * dentry,struct inode * inode,const char * name,void * buffer,size_t size)625 static 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 
xattr_set(const struct xattr_handler * handler,struct dentry * dentry,struct inode * inode,const char * name,const void * value,size_t size,int flags)636 static 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 
652 static const struct xattr_handler ubifs_user_xattr_handler = {
653 	.prefix = XATTR_USER_PREFIX,
654 	.get = xattr_get,
655 	.set = xattr_set,
656 };
657 
658 static 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
665 static 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 
672 const 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 };
680