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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2007 Red Hat. All rights reserved.
4 */
5
6#include <linux/init.h>
7#include <linux/fs.h>
8#include <linux/slab.h>
9#include <linux/rwsem.h>
10#include <linux/xattr.h>
11#include <linux/security.h>
12#include <linux/posix_acl_xattr.h>
13#include <linux/iversion.h>
14#include <linux/sched/mm.h>
15#include "ctree.h"
16#include "fs.h"
17#include "messages.h"
18#include "btrfs_inode.h"
19#include "transaction.h"
20#include "xattr.h"
21#include "disk-io.h"
22#include "props.h"
23#include "locking.h"
24#include "accessors.h"
25#include "dir-item.h"
26
27int btrfs_getxattr(struct inode *inode, const char *name,
28 void *buffer, size_t size)
29{
30 struct btrfs_dir_item *di;
31 struct btrfs_root *root = BTRFS_I(inode)->root;
32 struct btrfs_path *path;
33 struct extent_buffer *leaf;
34 int ret = 0;
35 unsigned long data_ptr;
36
37 path = btrfs_alloc_path();
38 if (!path)
39 return -ENOMEM;
40
41 /* lookup the xattr by name */
42 di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(BTRFS_I(inode)),
43 name, strlen(name), 0);
44 if (!di) {
45 ret = -ENODATA;
46 goto out;
47 } else if (IS_ERR(di)) {
48 ret = PTR_ERR(di);
49 goto out;
50 }
51
52 leaf = path->nodes[0];
53 /* if size is 0, that means we want the size of the attr */
54 if (!size) {
55 ret = btrfs_dir_data_len(leaf, di);
56 goto out;
57 }
58
59 /* now get the data out of our dir_item */
60 if (btrfs_dir_data_len(leaf, di) > size) {
61 ret = -ERANGE;
62 goto out;
63 }
64
65 /*
66 * The way things are packed into the leaf is like this
67 * |struct btrfs_dir_item|name|data|
68 * where name is the xattr name, so security.foo, and data is the
69 * content of the xattr. data_ptr points to the location in memory
70 * where the data starts in the in memory leaf
71 */
72 data_ptr = (unsigned long)((char *)(di + 1) +
73 btrfs_dir_name_len(leaf, di));
74 read_extent_buffer(leaf, buffer, data_ptr,
75 btrfs_dir_data_len(leaf, di));
76 ret = btrfs_dir_data_len(leaf, di);
77
78out:
79 btrfs_free_path(path);
80 return ret;
81}
82
83int btrfs_setxattr(struct btrfs_trans_handle *trans, struct inode *inode,
84 const char *name, const void *value, size_t size, int flags)
85{
86 struct btrfs_dir_item *di = NULL;
87 struct btrfs_root *root = BTRFS_I(inode)->root;
88 struct btrfs_fs_info *fs_info = root->fs_info;
89 struct btrfs_path *path;
90 size_t name_len = strlen(name);
91 int ret = 0;
92
93 ASSERT(trans);
94
95 if (name_len + size > BTRFS_MAX_XATTR_SIZE(root->fs_info))
96 return -ENOSPC;
97
98 path = btrfs_alloc_path();
99 if (!path)
100 return -ENOMEM;
101 path->skip_release_on_error = 1;
102
103 if (!value) {
104 di = btrfs_lookup_xattr(trans, root, path,
105 btrfs_ino(BTRFS_I(inode)), name, name_len, -1);
106 if (!di && (flags & XATTR_REPLACE))
107 ret = -ENODATA;
108 else if (IS_ERR(di))
109 ret = PTR_ERR(di);
110 else if (di)
111 ret = btrfs_delete_one_dir_name(trans, root, path, di);
112 goto out;
113 }
114
115 /*
116 * For a replace we can't just do the insert blindly.
117 * Do a lookup first (read-only btrfs_search_slot), and return if xattr
118 * doesn't exist. If it exists, fall down below to the insert/replace
119 * path - we can't race with a concurrent xattr delete, because the VFS
120 * locks the inode's i_mutex before calling setxattr or removexattr.
121 */
122 if (flags & XATTR_REPLACE) {
123 ASSERT(inode_is_locked(inode));
124 di = btrfs_lookup_xattr(NULL, root, path,
125 btrfs_ino(BTRFS_I(inode)), name, name_len, 0);
126 if (!di)
127 ret = -ENODATA;
128 else if (IS_ERR(di))
129 ret = PTR_ERR(di);
130 if (ret)
131 goto out;
132 btrfs_release_path(path);
133 di = NULL;
134 }
135
136 ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(BTRFS_I(inode)),
137 name, name_len, value, size);
138 if (ret == -EOVERFLOW) {
139 /*
140 * We have an existing item in a leaf, split_leaf couldn't
141 * expand it. That item might have or not a dir_item that
142 * matches our target xattr, so lets check.
143 */
144 ret = 0;
145 btrfs_assert_tree_write_locked(path->nodes[0]);
146 di = btrfs_match_dir_item_name(fs_info, path, name, name_len);
147 if (!di && !(flags & XATTR_REPLACE)) {
148 ret = -ENOSPC;
149 goto out;
150 }
151 } else if (ret == -EEXIST) {
152 ret = 0;
153 di = btrfs_match_dir_item_name(fs_info, path, name, name_len);
154 ASSERT(di); /* logic error */
155 } else if (ret) {
156 goto out;
157 }
158
159 if (di && (flags & XATTR_CREATE)) {
160 ret = -EEXIST;
161 goto out;
162 }
163
164 if (di) {
165 /*
166 * We're doing a replace, and it must be atomic, that is, at
167 * any point in time we have either the old or the new xattr
168 * value in the tree. We don't want readers (getxattr and
169 * listxattrs) to miss a value, this is specially important
170 * for ACLs.
171 */
172 const int slot = path->slots[0];
173 struct extent_buffer *leaf = path->nodes[0];
174 const u16 old_data_len = btrfs_dir_data_len(leaf, di);
175 const u32 item_size = btrfs_item_size(leaf, slot);
176 const u32 data_size = sizeof(*di) + name_len + size;
177 unsigned long data_ptr;
178 char *ptr;
179
180 if (size > old_data_len) {
181 if (btrfs_leaf_free_space(leaf) <
182 (size - old_data_len)) {
183 ret = -ENOSPC;
184 goto out;
185 }
186 }
187
188 if (old_data_len + name_len + sizeof(*di) == item_size) {
189 /* No other xattrs packed in the same leaf item. */
190 if (size > old_data_len)
191 btrfs_extend_item(trans, path, size - old_data_len);
192 else if (size < old_data_len)
193 btrfs_truncate_item(trans, path, data_size, 1);
194 } else {
195 /* There are other xattrs packed in the same item. */
196 ret = btrfs_delete_one_dir_name(trans, root, path, di);
197 if (ret)
198 goto out;
199 btrfs_extend_item(trans, path, data_size);
200 }
201
202 ptr = btrfs_item_ptr(leaf, slot, char);
203 ptr += btrfs_item_size(leaf, slot) - data_size;
204 di = (struct btrfs_dir_item *)ptr;
205 btrfs_set_dir_data_len(leaf, di, size);
206 data_ptr = ((unsigned long)(di + 1)) + name_len;
207 write_extent_buffer(leaf, value, data_ptr, size);
208 btrfs_mark_buffer_dirty(trans, leaf);
209 } else {
210 /*
211 * Insert, and we had space for the xattr, so path->slots[0] is
212 * where our xattr dir_item is and btrfs_insert_xattr_item()
213 * filled it.
214 */
215 }
216out:
217 btrfs_free_path(path);
218 if (!ret) {
219 set_bit(BTRFS_INODE_COPY_EVERYTHING,
220 &BTRFS_I(inode)->runtime_flags);
221 clear_bit(BTRFS_INODE_NO_XATTRS, &BTRFS_I(inode)->runtime_flags);
222 }
223 return ret;
224}
225
226/*
227 * @value: "" makes the attribute to empty, NULL removes it
228 */
229int btrfs_setxattr_trans(struct inode *inode, const char *name,
230 const void *value, size_t size, int flags)
231{
232 struct btrfs_root *root = BTRFS_I(inode)->root;
233 struct btrfs_trans_handle *trans;
234 const bool start_trans = (current->journal_info == NULL);
235 int ret;
236
237 if (start_trans) {
238 /*
239 * 1 unit for inserting/updating/deleting the xattr
240 * 1 unit for the inode item update
241 */
242 trans = btrfs_start_transaction(root, 2);
243 if (IS_ERR(trans))
244 return PTR_ERR(trans);
245 } else {
246 /*
247 * This can happen when smack is enabled and a directory is being
248 * created. It happens through d_instantiate_new(), which calls
249 * smack_d_instantiate(), which in turn calls __vfs_setxattr() to
250 * set the transmute xattr (XATTR_NAME_SMACKTRANSMUTE) on the
251 * inode. We have already reserved space for the xattr and inode
252 * update at btrfs_mkdir(), so just use the transaction handle.
253 * We don't join or start a transaction, as that will reset the
254 * block_rsv of the handle and trigger a warning for the start
255 * case.
256 */
257 ASSERT(strncmp(name, XATTR_SECURITY_PREFIX,
258 XATTR_SECURITY_PREFIX_LEN) == 0);
259 trans = current->journal_info;
260 }
261
262 ret = btrfs_setxattr(trans, inode, name, value, size, flags);
263 if (ret)
264 goto out;
265
266 inode_inc_iversion(inode);
267 inode_set_ctime_current(inode);
268 ret = btrfs_update_inode(trans, BTRFS_I(inode));
269 if (ret)
270 btrfs_abort_transaction(trans, ret);
271out:
272 if (start_trans)
273 btrfs_end_transaction(trans);
274 return ret;
275}
276
277ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
278{
279 struct btrfs_key found_key;
280 struct btrfs_key key;
281 struct inode *inode = d_inode(dentry);
282 struct btrfs_root *root = BTRFS_I(inode)->root;
283 struct btrfs_path *path;
284 int iter_ret = 0;
285 int ret = 0;
286 size_t total_size = 0, size_left = size;
287
288 /*
289 * ok we want all objects associated with this id.
290 * NOTE: we set key.offset = 0; because we want to start with the
291 * first xattr that we find and walk forward
292 */
293 key.objectid = btrfs_ino(BTRFS_I(inode));
294 key.type = BTRFS_XATTR_ITEM_KEY;
295 key.offset = 0;
296
297 path = btrfs_alloc_path();
298 if (!path)
299 return -ENOMEM;
300 path->reada = READA_FORWARD;
301
302 /* search for our xattrs */
303 btrfs_for_each_slot(root, &key, &found_key, path, iter_ret) {
304 struct extent_buffer *leaf;
305 int slot;
306 struct btrfs_dir_item *di;
307 u32 item_size;
308 u32 cur;
309
310 leaf = path->nodes[0];
311 slot = path->slots[0];
312
313 /* check to make sure this item is what we want */
314 if (found_key.objectid != key.objectid)
315 break;
316 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
317 break;
318 if (found_key.type < BTRFS_XATTR_ITEM_KEY)
319 continue;
320
321 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
322 item_size = btrfs_item_size(leaf, slot);
323 cur = 0;
324 while (cur < item_size) {
325 u16 name_len = btrfs_dir_name_len(leaf, di);
326 u16 data_len = btrfs_dir_data_len(leaf, di);
327 u32 this_len = sizeof(*di) + name_len + data_len;
328 unsigned long name_ptr = (unsigned long)(di + 1);
329
330 total_size += name_len + 1;
331 /*
332 * We are just looking for how big our buffer needs to
333 * be.
334 */
335 if (!size)
336 goto next;
337
338 if (!buffer || (name_len + 1) > size_left) {
339 iter_ret = -ERANGE;
340 break;
341 }
342
343 read_extent_buffer(leaf, buffer, name_ptr, name_len);
344 buffer[name_len] = '\0';
345
346 size_left -= name_len + 1;
347 buffer += name_len + 1;
348next:
349 cur += this_len;
350 di = (struct btrfs_dir_item *)((char *)di + this_len);
351 }
352 }
353
354 if (iter_ret < 0)
355 ret = iter_ret;
356 else
357 ret = total_size;
358
359 btrfs_free_path(path);
360
361 return ret;
362}
363
364static int btrfs_xattr_handler_get(const struct xattr_handler *handler,
365 struct dentry *unused, struct inode *inode,
366 const char *name, void *buffer, size_t size)
367{
368 name = xattr_full_name(handler, name);
369 return btrfs_getxattr(inode, name, buffer, size);
370}
371
372static int btrfs_xattr_handler_set(const struct xattr_handler *handler,
373 struct mnt_idmap *idmap,
374 struct dentry *unused, struct inode *inode,
375 const char *name, const void *buffer,
376 size_t size, int flags)
377{
378 if (btrfs_root_readonly(BTRFS_I(inode)->root))
379 return -EROFS;
380
381 name = xattr_full_name(handler, name);
382 return btrfs_setxattr_trans(inode, name, buffer, size, flags);
383}
384
385static int btrfs_xattr_handler_get_security(const struct xattr_handler *handler,
386 struct dentry *unused,
387 struct inode *inode,
388 const char *name, void *buffer,
389 size_t size)
390{
391 int ret;
392 bool is_cap = false;
393
394 name = xattr_full_name(handler, name);
395
396 /*
397 * security.capability doesn't cache the results, so calls into us
398 * constantly to see if there's a capability xattr. Cache the result
399 * here in order to avoid wasting time doing lookups for xattrs we know
400 * don't exist.
401 */
402 if (strcmp(name, XATTR_NAME_CAPS) == 0) {
403 is_cap = true;
404 if (test_bit(BTRFS_INODE_NO_CAP_XATTR, &BTRFS_I(inode)->runtime_flags))
405 return -ENODATA;
406 }
407
408 ret = btrfs_getxattr(inode, name, buffer, size);
409 if (ret == -ENODATA && is_cap)
410 set_bit(BTRFS_INODE_NO_CAP_XATTR, &BTRFS_I(inode)->runtime_flags);
411 return ret;
412}
413
414static int btrfs_xattr_handler_set_security(const struct xattr_handler *handler,
415 struct mnt_idmap *idmap,
416 struct dentry *unused,
417 struct inode *inode,
418 const char *name,
419 const void *buffer,
420 size_t size, int flags)
421{
422 if (btrfs_root_readonly(BTRFS_I(inode)->root))
423 return -EROFS;
424
425 name = xattr_full_name(handler, name);
426 if (strcmp(name, XATTR_NAME_CAPS) == 0)
427 clear_bit(BTRFS_INODE_NO_CAP_XATTR, &BTRFS_I(inode)->runtime_flags);
428
429 return btrfs_setxattr_trans(inode, name, buffer, size, flags);
430}
431
432static int btrfs_xattr_handler_set_prop(const struct xattr_handler *handler,
433 struct mnt_idmap *idmap,
434 struct dentry *unused, struct inode *inode,
435 const char *name, const void *value,
436 size_t size, int flags)
437{
438 int ret;
439 struct btrfs_trans_handle *trans;
440 struct btrfs_root *root = BTRFS_I(inode)->root;
441
442 name = xattr_full_name(handler, name);
443 ret = btrfs_validate_prop(BTRFS_I(inode), name, value, size);
444 if (ret)
445 return ret;
446
447 if (btrfs_ignore_prop(BTRFS_I(inode), name))
448 return 0;
449
450 trans = btrfs_start_transaction(root, 2);
451 if (IS_ERR(trans))
452 return PTR_ERR(trans);
453
454 ret = btrfs_set_prop(trans, inode, name, value, size, flags);
455 if (!ret) {
456 inode_inc_iversion(inode);
457 inode_set_ctime_current(inode);
458 ret = btrfs_update_inode(trans, BTRFS_I(inode));
459 if (ret)
460 btrfs_abort_transaction(trans, ret);
461 }
462
463 btrfs_end_transaction(trans);
464
465 return ret;
466}
467
468static const struct xattr_handler btrfs_security_xattr_handler = {
469 .prefix = XATTR_SECURITY_PREFIX,
470 .get = btrfs_xattr_handler_get_security,
471 .set = btrfs_xattr_handler_set_security,
472};
473
474static const struct xattr_handler btrfs_trusted_xattr_handler = {
475 .prefix = XATTR_TRUSTED_PREFIX,
476 .get = btrfs_xattr_handler_get,
477 .set = btrfs_xattr_handler_set,
478};
479
480static const struct xattr_handler btrfs_user_xattr_handler = {
481 .prefix = XATTR_USER_PREFIX,
482 .get = btrfs_xattr_handler_get,
483 .set = btrfs_xattr_handler_set,
484};
485
486static const struct xattr_handler btrfs_btrfs_xattr_handler = {
487 .prefix = XATTR_BTRFS_PREFIX,
488 .get = btrfs_xattr_handler_get,
489 .set = btrfs_xattr_handler_set_prop,
490};
491
492const struct xattr_handler * const btrfs_xattr_handlers[] = {
493 &btrfs_security_xattr_handler,
494 &btrfs_trusted_xattr_handler,
495 &btrfs_user_xattr_handler,
496 &btrfs_btrfs_xattr_handler,
497 NULL,
498};
499
500static int btrfs_initxattrs(struct inode *inode,
501 const struct xattr *xattr_array, void *fs_private)
502{
503 struct btrfs_trans_handle *trans = fs_private;
504 const struct xattr *xattr;
505 unsigned int nofs_flag;
506 char *name;
507 int err = 0;
508
509 /*
510 * We're holding a transaction handle, so use a NOFS memory allocation
511 * context to avoid deadlock if reclaim happens.
512 */
513 nofs_flag = memalloc_nofs_save();
514 for (xattr = xattr_array; xattr->name != NULL; xattr++) {
515 name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
516 strlen(xattr->name) + 1, GFP_KERNEL);
517 if (!name) {
518 err = -ENOMEM;
519 break;
520 }
521 strcpy(name, XATTR_SECURITY_PREFIX);
522 strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
523
524 if (strcmp(name, XATTR_NAME_CAPS) == 0)
525 clear_bit(BTRFS_INODE_NO_CAP_XATTR, &BTRFS_I(inode)->runtime_flags);
526
527 err = btrfs_setxattr(trans, inode, name, xattr->value,
528 xattr->value_len, 0);
529 kfree(name);
530 if (err < 0)
531 break;
532 }
533 memalloc_nofs_restore(nofs_flag);
534 return err;
535}
536
537int btrfs_xattr_security_init(struct btrfs_trans_handle *trans,
538 struct inode *inode, struct inode *dir,
539 const struct qstr *qstr)
540{
541 return security_inode_init_security(inode, dir, qstr,
542 &btrfs_initxattrs, trans);
543}
1/*
2 * Copyright (C) 2007 Red Hat. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19#include <linux/init.h>
20#include <linux/fs.h>
21#include <linux/slab.h>
22#include <linux/rwsem.h>
23#include <linux/xattr.h>
24#include <linux/security.h>
25#include <linux/posix_acl_xattr.h>
26#include "ctree.h"
27#include "btrfs_inode.h"
28#include "transaction.h"
29#include "xattr.h"
30#include "disk-io.h"
31#include "props.h"
32
33
34ssize_t __btrfs_getxattr(struct inode *inode, const char *name,
35 void *buffer, size_t size)
36{
37 struct btrfs_dir_item *di;
38 struct btrfs_root *root = BTRFS_I(inode)->root;
39 struct btrfs_path *path;
40 struct extent_buffer *leaf;
41 int ret = 0;
42 unsigned long data_ptr;
43
44 path = btrfs_alloc_path();
45 if (!path)
46 return -ENOMEM;
47
48 /* lookup the xattr by name */
49 di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(inode), name,
50 strlen(name), 0);
51 if (!di) {
52 ret = -ENODATA;
53 goto out;
54 } else if (IS_ERR(di)) {
55 ret = PTR_ERR(di);
56 goto out;
57 }
58
59 leaf = path->nodes[0];
60 /* if size is 0, that means we want the size of the attr */
61 if (!size) {
62 ret = btrfs_dir_data_len(leaf, di);
63 goto out;
64 }
65
66 /* now get the data out of our dir_item */
67 if (btrfs_dir_data_len(leaf, di) > size) {
68 ret = -ERANGE;
69 goto out;
70 }
71
72 /*
73 * The way things are packed into the leaf is like this
74 * |struct btrfs_dir_item|name|data|
75 * where name is the xattr name, so security.foo, and data is the
76 * content of the xattr. data_ptr points to the location in memory
77 * where the data starts in the in memory leaf
78 */
79 data_ptr = (unsigned long)((char *)(di + 1) +
80 btrfs_dir_name_len(leaf, di));
81 read_extent_buffer(leaf, buffer, data_ptr,
82 btrfs_dir_data_len(leaf, di));
83 ret = btrfs_dir_data_len(leaf, di);
84
85out:
86 btrfs_free_path(path);
87 return ret;
88}
89
90static int do_setxattr(struct btrfs_trans_handle *trans,
91 struct inode *inode, const char *name,
92 const void *value, size_t size, int flags)
93{
94 struct btrfs_dir_item *di;
95 struct btrfs_root *root = BTRFS_I(inode)->root;
96 struct btrfs_path *path;
97 size_t name_len = strlen(name);
98 int ret = 0;
99
100 if (name_len + size > BTRFS_MAX_XATTR_SIZE(root))
101 return -ENOSPC;
102
103 path = btrfs_alloc_path();
104 if (!path)
105 return -ENOMEM;
106
107 if (flags & XATTR_REPLACE) {
108 di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(inode), name,
109 name_len, -1);
110 if (IS_ERR(di)) {
111 ret = PTR_ERR(di);
112 goto out;
113 } else if (!di) {
114 ret = -ENODATA;
115 goto out;
116 }
117 ret = btrfs_delete_one_dir_name(trans, root, path, di);
118 if (ret)
119 goto out;
120 btrfs_release_path(path);
121
122 /*
123 * remove the attribute
124 */
125 if (!value)
126 goto out;
127 } else {
128 di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(inode),
129 name, name_len, 0);
130 if (IS_ERR(di)) {
131 ret = PTR_ERR(di);
132 goto out;
133 }
134 if (!di && !value)
135 goto out;
136 btrfs_release_path(path);
137 }
138
139again:
140 ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(inode),
141 name, name_len, value, size);
142 /*
143 * If we're setting an xattr to a new value but the new value is say
144 * exactly BTRFS_MAX_XATTR_SIZE, we could end up with EOVERFLOW getting
145 * back from split_leaf. This is because it thinks we'll be extending
146 * the existing item size, but we're asking for enough space to add the
147 * item itself. So if we get EOVERFLOW just set ret to EEXIST and let
148 * the rest of the function figure it out.
149 */
150 if (ret == -EOVERFLOW)
151 ret = -EEXIST;
152
153 if (ret == -EEXIST) {
154 if (flags & XATTR_CREATE)
155 goto out;
156 /*
157 * We can't use the path we already have since we won't have the
158 * proper locking for a delete, so release the path and
159 * re-lookup to delete the thing.
160 */
161 btrfs_release_path(path);
162 di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(inode),
163 name, name_len, -1);
164 if (IS_ERR(di)) {
165 ret = PTR_ERR(di);
166 goto out;
167 } else if (!di) {
168 /* Shouldn't happen but just in case... */
169 btrfs_release_path(path);
170 goto again;
171 }
172
173 ret = btrfs_delete_one_dir_name(trans, root, path, di);
174 if (ret)
175 goto out;
176
177 /*
178 * We have a value to set, so go back and try to insert it now.
179 */
180 if (value) {
181 btrfs_release_path(path);
182 goto again;
183 }
184 }
185out:
186 btrfs_free_path(path);
187 return ret;
188}
189
190/*
191 * @value: "" makes the attribute to empty, NULL removes it
192 */
193int __btrfs_setxattr(struct btrfs_trans_handle *trans,
194 struct inode *inode, const char *name,
195 const void *value, size_t size, int flags)
196{
197 struct btrfs_root *root = BTRFS_I(inode)->root;
198 int ret;
199
200 if (trans)
201 return do_setxattr(trans, inode, name, value, size, flags);
202
203 trans = btrfs_start_transaction(root, 2);
204 if (IS_ERR(trans))
205 return PTR_ERR(trans);
206
207 ret = do_setxattr(trans, inode, name, value, size, flags);
208 if (ret)
209 goto out;
210
211 inode_inc_iversion(inode);
212 inode->i_ctime = CURRENT_TIME;
213 set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
214 ret = btrfs_update_inode(trans, root, inode);
215 BUG_ON(ret);
216out:
217 btrfs_end_transaction(trans, root);
218 return ret;
219}
220
221ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
222{
223 struct btrfs_key key, found_key;
224 struct inode *inode = dentry->d_inode;
225 struct btrfs_root *root = BTRFS_I(inode)->root;
226 struct btrfs_path *path;
227 struct extent_buffer *leaf;
228 struct btrfs_dir_item *di;
229 int ret = 0, slot;
230 size_t total_size = 0, size_left = size;
231 unsigned long name_ptr;
232 size_t name_len;
233
234 /*
235 * ok we want all objects associated with this id.
236 * NOTE: we set key.offset = 0; because we want to start with the
237 * first xattr that we find and walk forward
238 */
239 key.objectid = btrfs_ino(inode);
240 btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
241 key.offset = 0;
242
243 path = btrfs_alloc_path();
244 if (!path)
245 return -ENOMEM;
246 path->reada = 2;
247
248 /* search for our xattrs */
249 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
250 if (ret < 0)
251 goto err;
252
253 while (1) {
254 leaf = path->nodes[0];
255 slot = path->slots[0];
256
257 /* this is where we start walking through the path */
258 if (slot >= btrfs_header_nritems(leaf)) {
259 /*
260 * if we've reached the last slot in this leaf we need
261 * to go to the next leaf and reset everything
262 */
263 ret = btrfs_next_leaf(root, path);
264 if (ret < 0)
265 goto err;
266 else if (ret > 0)
267 break;
268 continue;
269 }
270
271 btrfs_item_key_to_cpu(leaf, &found_key, slot);
272
273 /* check to make sure this item is what we want */
274 if (found_key.objectid != key.objectid)
275 break;
276 if (btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY)
277 break;
278
279 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
280 if (verify_dir_item(root, leaf, di))
281 goto next;
282
283 name_len = btrfs_dir_name_len(leaf, di);
284 total_size += name_len + 1;
285
286 /* we are just looking for how big our buffer needs to be */
287 if (!size)
288 goto next;
289
290 if (!buffer || (name_len + 1) > size_left) {
291 ret = -ERANGE;
292 goto err;
293 }
294
295 name_ptr = (unsigned long)(di + 1);
296 read_extent_buffer(leaf, buffer, name_ptr, name_len);
297 buffer[name_len] = '\0';
298
299 size_left -= name_len + 1;
300 buffer += name_len + 1;
301next:
302 path->slots[0]++;
303 }
304 ret = total_size;
305
306err:
307 btrfs_free_path(path);
308
309 return ret;
310}
311
312/*
313 * List of handlers for synthetic system.* attributes. All real ondisk
314 * attributes are handled directly.
315 */
316const struct xattr_handler *btrfs_xattr_handlers[] = {
317#ifdef CONFIG_BTRFS_FS_POSIX_ACL
318 &posix_acl_access_xattr_handler,
319 &posix_acl_default_xattr_handler,
320#endif
321 NULL,
322};
323
324/*
325 * Check if the attribute is in a supported namespace.
326 *
327 * This applied after the check for the synthetic attributes in the system
328 * namespace.
329 */
330static bool btrfs_is_valid_xattr(const char *name)
331{
332 return !strncmp(name, XATTR_SECURITY_PREFIX,
333 XATTR_SECURITY_PREFIX_LEN) ||
334 !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) ||
335 !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) ||
336 !strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN) ||
337 !strncmp(name, XATTR_BTRFS_PREFIX, XATTR_BTRFS_PREFIX_LEN);
338}
339
340ssize_t btrfs_getxattr(struct dentry *dentry, const char *name,
341 void *buffer, size_t size)
342{
343 /*
344 * If this is a request for a synthetic attribute in the system.*
345 * namespace use the generic infrastructure to resolve a handler
346 * for it via sb->s_xattr.
347 */
348 if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
349 return generic_getxattr(dentry, name, buffer, size);
350
351 if (!btrfs_is_valid_xattr(name))
352 return -EOPNOTSUPP;
353 return __btrfs_getxattr(dentry->d_inode, name, buffer, size);
354}
355
356int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value,
357 size_t size, int flags)
358{
359 struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root;
360
361 /*
362 * The permission on security.* and system.* is not checked
363 * in permission().
364 */
365 if (btrfs_root_readonly(root))
366 return -EROFS;
367
368 /*
369 * If this is a request for a synthetic attribute in the system.*
370 * namespace use the generic infrastructure to resolve a handler
371 * for it via sb->s_xattr.
372 */
373 if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
374 return generic_setxattr(dentry, name, value, size, flags);
375
376 if (!btrfs_is_valid_xattr(name))
377 return -EOPNOTSUPP;
378
379 if (!strncmp(name, XATTR_BTRFS_PREFIX, XATTR_BTRFS_PREFIX_LEN))
380 return btrfs_set_prop(dentry->d_inode, name,
381 value, size, flags);
382
383 if (size == 0)
384 value = ""; /* empty EA, do not remove */
385
386 return __btrfs_setxattr(NULL, dentry->d_inode, name, value, size,
387 flags);
388}
389
390int btrfs_removexattr(struct dentry *dentry, const char *name)
391{
392 struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root;
393
394 /*
395 * The permission on security.* and system.* is not checked
396 * in permission().
397 */
398 if (btrfs_root_readonly(root))
399 return -EROFS;
400
401 /*
402 * If this is a request for a synthetic attribute in the system.*
403 * namespace use the generic infrastructure to resolve a handler
404 * for it via sb->s_xattr.
405 */
406 if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
407 return generic_removexattr(dentry, name);
408
409 if (!btrfs_is_valid_xattr(name))
410 return -EOPNOTSUPP;
411
412 if (!strncmp(name, XATTR_BTRFS_PREFIX, XATTR_BTRFS_PREFIX_LEN))
413 return btrfs_set_prop(dentry->d_inode, name,
414 NULL, 0, XATTR_REPLACE);
415
416 return __btrfs_setxattr(NULL, dentry->d_inode, name, NULL, 0,
417 XATTR_REPLACE);
418}
419
420static int btrfs_initxattrs(struct inode *inode,
421 const struct xattr *xattr_array, void *fs_info)
422{
423 const struct xattr *xattr;
424 struct btrfs_trans_handle *trans = fs_info;
425 char *name;
426 int err = 0;
427
428 for (xattr = xattr_array; xattr->name != NULL; xattr++) {
429 name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
430 strlen(xattr->name) + 1, GFP_NOFS);
431 if (!name) {
432 err = -ENOMEM;
433 break;
434 }
435 strcpy(name, XATTR_SECURITY_PREFIX);
436 strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
437 err = __btrfs_setxattr(trans, inode, name,
438 xattr->value, xattr->value_len, 0);
439 kfree(name);
440 if (err < 0)
441 break;
442 }
443 return err;
444}
445
446int btrfs_xattr_security_init(struct btrfs_trans_handle *trans,
447 struct inode *inode, struct inode *dir,
448 const struct qstr *qstr)
449{
450 return security_inode_init_security(inode, dir, qstr,
451 &btrfs_initxattrs, trans);
452}