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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// 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 "btrfs_inode.h"
17#include "transaction.h"
18#include "xattr.h"
19#include "disk-io.h"
20#include "props.h"
21#include "locking.h"
22
23int btrfs_getxattr(struct inode *inode, const char *name,
24 void *buffer, size_t size)
25{
26 struct btrfs_dir_item *di;
27 struct btrfs_root *root = BTRFS_I(inode)->root;
28 struct btrfs_path *path;
29 struct extent_buffer *leaf;
30 int ret = 0;
31 unsigned long data_ptr;
32
33 path = btrfs_alloc_path();
34 if (!path)
35 return -ENOMEM;
36
37 /* lookup the xattr by name */
38 di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(BTRFS_I(inode)),
39 name, strlen(name), 0);
40 if (!di) {
41 ret = -ENODATA;
42 goto out;
43 } else if (IS_ERR(di)) {
44 ret = PTR_ERR(di);
45 goto out;
46 }
47
48 leaf = path->nodes[0];
49 /* if size is 0, that means we want the size of the attr */
50 if (!size) {
51 ret = btrfs_dir_data_len(leaf, di);
52 goto out;
53 }
54
55 /* now get the data out of our dir_item */
56 if (btrfs_dir_data_len(leaf, di) > size) {
57 ret = -ERANGE;
58 goto out;
59 }
60
61 /*
62 * The way things are packed into the leaf is like this
63 * |struct btrfs_dir_item|name|data|
64 * where name is the xattr name, so security.foo, and data is the
65 * content of the xattr. data_ptr points to the location in memory
66 * where the data starts in the in memory leaf
67 */
68 data_ptr = (unsigned long)((char *)(di + 1) +
69 btrfs_dir_name_len(leaf, di));
70 read_extent_buffer(leaf, buffer, data_ptr,
71 btrfs_dir_data_len(leaf, di));
72 ret = btrfs_dir_data_len(leaf, di);
73
74out:
75 btrfs_free_path(path);
76 return ret;
77}
78
79int btrfs_setxattr(struct btrfs_trans_handle *trans, struct inode *inode,
80 const char *name, const void *value, size_t size, int flags)
81{
82 struct btrfs_dir_item *di = NULL;
83 struct btrfs_root *root = BTRFS_I(inode)->root;
84 struct btrfs_fs_info *fs_info = root->fs_info;
85 struct btrfs_path *path;
86 size_t name_len = strlen(name);
87 int ret = 0;
88
89 ASSERT(trans);
90
91 if (name_len + size > BTRFS_MAX_XATTR_SIZE(root->fs_info))
92 return -ENOSPC;
93
94 path = btrfs_alloc_path();
95 if (!path)
96 return -ENOMEM;
97 path->skip_release_on_error = 1;
98
99 if (!value) {
100 di = btrfs_lookup_xattr(trans, root, path,
101 btrfs_ino(BTRFS_I(inode)), name, name_len, -1);
102 if (!di && (flags & XATTR_REPLACE))
103 ret = -ENODATA;
104 else if (IS_ERR(di))
105 ret = PTR_ERR(di);
106 else if (di)
107 ret = btrfs_delete_one_dir_name(trans, root, path, di);
108 goto out;
109 }
110
111 /*
112 * For a replace we can't just do the insert blindly.
113 * Do a lookup first (read-only btrfs_search_slot), and return if xattr
114 * doesn't exist. If it exists, fall down below to the insert/replace
115 * path - we can't race with a concurrent xattr delete, because the VFS
116 * locks the inode's i_mutex before calling setxattr or removexattr.
117 */
118 if (flags & XATTR_REPLACE) {
119 ASSERT(inode_is_locked(inode));
120 di = btrfs_lookup_xattr(NULL, root, path,
121 btrfs_ino(BTRFS_I(inode)), name, name_len, 0);
122 if (!di)
123 ret = -ENODATA;
124 else if (IS_ERR(di))
125 ret = PTR_ERR(di);
126 if (ret)
127 goto out;
128 btrfs_release_path(path);
129 di = NULL;
130 }
131
132 ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(BTRFS_I(inode)),
133 name, name_len, value, size);
134 if (ret == -EOVERFLOW) {
135 /*
136 * We have an existing item in a leaf, split_leaf couldn't
137 * expand it. That item might have or not a dir_item that
138 * matches our target xattr, so lets check.
139 */
140 ret = 0;
141 btrfs_assert_tree_locked(path->nodes[0]);
142 di = btrfs_match_dir_item_name(fs_info, path, name, name_len);
143 if (!di && !(flags & XATTR_REPLACE)) {
144 ret = -ENOSPC;
145 goto out;
146 }
147 } else if (ret == -EEXIST) {
148 ret = 0;
149 di = btrfs_match_dir_item_name(fs_info, path, name, name_len);
150 ASSERT(di); /* logic error */
151 } else if (ret) {
152 goto out;
153 }
154
155 if (di && (flags & XATTR_CREATE)) {
156 ret = -EEXIST;
157 goto out;
158 }
159
160 if (di) {
161 /*
162 * We're doing a replace, and it must be atomic, that is, at
163 * any point in time we have either the old or the new xattr
164 * value in the tree. We don't want readers (getxattr and
165 * listxattrs) to miss a value, this is specially important
166 * for ACLs.
167 */
168 const int slot = path->slots[0];
169 struct extent_buffer *leaf = path->nodes[0];
170 const u16 old_data_len = btrfs_dir_data_len(leaf, di);
171 const u32 item_size = btrfs_item_size_nr(leaf, slot);
172 const u32 data_size = sizeof(*di) + name_len + size;
173 struct btrfs_item *item;
174 unsigned long data_ptr;
175 char *ptr;
176
177 if (size > old_data_len) {
178 if (btrfs_leaf_free_space(leaf) <
179 (size - old_data_len)) {
180 ret = -ENOSPC;
181 goto out;
182 }
183 }
184
185 if (old_data_len + name_len + sizeof(*di) == item_size) {
186 /* No other xattrs packed in the same leaf item. */
187 if (size > old_data_len)
188 btrfs_extend_item(path, size - old_data_len);
189 else if (size < old_data_len)
190 btrfs_truncate_item(path, data_size, 1);
191 } else {
192 /* There are other xattrs packed in the same item. */
193 ret = btrfs_delete_one_dir_name(trans, root, path, di);
194 if (ret)
195 goto out;
196 btrfs_extend_item(path, data_size);
197 }
198
199 item = btrfs_item_nr(slot);
200 ptr = btrfs_item_ptr(leaf, slot, char);
201 ptr += btrfs_item_size(leaf, item) - data_size;
202 di = (struct btrfs_dir_item *)ptr;
203 btrfs_set_dir_data_len(leaf, di, size);
204 data_ptr = ((unsigned long)(di + 1)) + name_len;
205 write_extent_buffer(leaf, value, data_ptr, size);
206 btrfs_mark_buffer_dirty(leaf);
207 } else {
208 /*
209 * Insert, and we had space for the xattr, so path->slots[0] is
210 * where our xattr dir_item is and btrfs_insert_xattr_item()
211 * filled it.
212 */
213 }
214out:
215 btrfs_free_path(path);
216 if (!ret)
217 set_bit(BTRFS_INODE_COPY_EVERYTHING,
218 &BTRFS_I(inode)->runtime_flags);
219 return ret;
220}
221
222/*
223 * @value: "" makes the attribute to empty, NULL removes it
224 */
225int btrfs_setxattr_trans(struct inode *inode, const char *name,
226 const void *value, size_t size, int flags)
227{
228 struct btrfs_root *root = BTRFS_I(inode)->root;
229 struct btrfs_trans_handle *trans;
230 int ret;
231
232 trans = btrfs_start_transaction(root, 2);
233 if (IS_ERR(trans))
234 return PTR_ERR(trans);
235
236 ret = btrfs_setxattr(trans, inode, name, value, size, flags);
237 if (ret)
238 goto out;
239
240 inode_inc_iversion(inode);
241 inode->i_ctime = current_time(inode);
242 ret = btrfs_update_inode(trans, root, inode);
243 BUG_ON(ret);
244out:
245 btrfs_end_transaction(trans);
246 return ret;
247}
248
249ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
250{
251 struct btrfs_key key;
252 struct inode *inode = d_inode(dentry);
253 struct btrfs_root *root = BTRFS_I(inode)->root;
254 struct btrfs_path *path;
255 int ret = 0;
256 size_t total_size = 0, size_left = size;
257
258 /*
259 * ok we want all objects associated with this id.
260 * NOTE: we set key.offset = 0; because we want to start with the
261 * first xattr that we find and walk forward
262 */
263 key.objectid = btrfs_ino(BTRFS_I(inode));
264 key.type = BTRFS_XATTR_ITEM_KEY;
265 key.offset = 0;
266
267 path = btrfs_alloc_path();
268 if (!path)
269 return -ENOMEM;
270 path->reada = READA_FORWARD;
271
272 /* search for our xattrs */
273 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
274 if (ret < 0)
275 goto err;
276
277 while (1) {
278 struct extent_buffer *leaf;
279 int slot;
280 struct btrfs_dir_item *di;
281 struct btrfs_key found_key;
282 u32 item_size;
283 u32 cur;
284
285 leaf = path->nodes[0];
286 slot = path->slots[0];
287
288 /* this is where we start walking through the path */
289 if (slot >= btrfs_header_nritems(leaf)) {
290 /*
291 * if we've reached the last slot in this leaf we need
292 * to go to the next leaf and reset everything
293 */
294 ret = btrfs_next_leaf(root, path);
295 if (ret < 0)
296 goto err;
297 else if (ret > 0)
298 break;
299 continue;
300 }
301
302 btrfs_item_key_to_cpu(leaf, &found_key, slot);
303
304 /* check to make sure this item is what we want */
305 if (found_key.objectid != key.objectid)
306 break;
307 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
308 break;
309 if (found_key.type < BTRFS_XATTR_ITEM_KEY)
310 goto next_item;
311
312 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
313 item_size = btrfs_item_size_nr(leaf, slot);
314 cur = 0;
315 while (cur < item_size) {
316 u16 name_len = btrfs_dir_name_len(leaf, di);
317 u16 data_len = btrfs_dir_data_len(leaf, di);
318 u32 this_len = sizeof(*di) + name_len + data_len;
319 unsigned long name_ptr = (unsigned long)(di + 1);
320
321 total_size += name_len + 1;
322 /*
323 * We are just looking for how big our buffer needs to
324 * be.
325 */
326 if (!size)
327 goto next;
328
329 if (!buffer || (name_len + 1) > size_left) {
330 ret = -ERANGE;
331 goto err;
332 }
333
334 read_extent_buffer(leaf, buffer, name_ptr, name_len);
335 buffer[name_len] = '\0';
336
337 size_left -= name_len + 1;
338 buffer += name_len + 1;
339next:
340 cur += this_len;
341 di = (struct btrfs_dir_item *)((char *)di + this_len);
342 }
343next_item:
344 path->slots[0]++;
345 }
346 ret = total_size;
347
348err:
349 btrfs_free_path(path);
350
351 return ret;
352}
353
354static int btrfs_xattr_handler_get(const struct xattr_handler *handler,
355 struct dentry *unused, struct inode *inode,
356 const char *name, void *buffer, size_t size)
357{
358 name = xattr_full_name(handler, name);
359 return btrfs_getxattr(inode, name, buffer, size);
360}
361
362static int btrfs_xattr_handler_set(const struct xattr_handler *handler,
363 struct dentry *unused, struct inode *inode,
364 const char *name, const void *buffer,
365 size_t size, int flags)
366{
367 name = xattr_full_name(handler, name);
368 return btrfs_setxattr_trans(inode, name, buffer, size, flags);
369}
370
371static int btrfs_xattr_handler_set_prop(const struct xattr_handler *handler,
372 struct dentry *unused, struct inode *inode,
373 const char *name, const void *value,
374 size_t size, int flags)
375{
376 int ret;
377 struct btrfs_trans_handle *trans;
378 struct btrfs_root *root = BTRFS_I(inode)->root;
379
380 name = xattr_full_name(handler, name);
381 ret = btrfs_validate_prop(name, value, size);
382 if (ret)
383 return ret;
384
385 trans = btrfs_start_transaction(root, 2);
386 if (IS_ERR(trans))
387 return PTR_ERR(trans);
388
389 ret = btrfs_set_prop(trans, inode, name, value, size, flags);
390 if (!ret) {
391 inode_inc_iversion(inode);
392 inode->i_ctime = current_time(inode);
393 ret = btrfs_update_inode(trans, root, inode);
394 BUG_ON(ret);
395 }
396
397 btrfs_end_transaction(trans);
398
399 return ret;
400}
401
402static const struct xattr_handler btrfs_security_xattr_handler = {
403 .prefix = XATTR_SECURITY_PREFIX,
404 .get = btrfs_xattr_handler_get,
405 .set = btrfs_xattr_handler_set,
406};
407
408static const struct xattr_handler btrfs_trusted_xattr_handler = {
409 .prefix = XATTR_TRUSTED_PREFIX,
410 .get = btrfs_xattr_handler_get,
411 .set = btrfs_xattr_handler_set,
412};
413
414static const struct xattr_handler btrfs_user_xattr_handler = {
415 .prefix = XATTR_USER_PREFIX,
416 .get = btrfs_xattr_handler_get,
417 .set = btrfs_xattr_handler_set,
418};
419
420static const struct xattr_handler btrfs_btrfs_xattr_handler = {
421 .prefix = XATTR_BTRFS_PREFIX,
422 .get = btrfs_xattr_handler_get,
423 .set = btrfs_xattr_handler_set_prop,
424};
425
426const struct xattr_handler *btrfs_xattr_handlers[] = {
427 &btrfs_security_xattr_handler,
428#ifdef CONFIG_BTRFS_FS_POSIX_ACL
429 &posix_acl_access_xattr_handler,
430 &posix_acl_default_xattr_handler,
431#endif
432 &btrfs_trusted_xattr_handler,
433 &btrfs_user_xattr_handler,
434 &btrfs_btrfs_xattr_handler,
435 NULL,
436};
437
438static int btrfs_initxattrs(struct inode *inode,
439 const struct xattr *xattr_array, void *fs_private)
440{
441 struct btrfs_trans_handle *trans = fs_private;
442 const struct xattr *xattr;
443 unsigned int nofs_flag;
444 char *name;
445 int err = 0;
446
447 /*
448 * We're holding a transaction handle, so use a NOFS memory allocation
449 * context to avoid deadlock if reclaim happens.
450 */
451 nofs_flag = memalloc_nofs_save();
452 for (xattr = xattr_array; xattr->name != NULL; xattr++) {
453 name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
454 strlen(xattr->name) + 1, GFP_KERNEL);
455 if (!name) {
456 err = -ENOMEM;
457 break;
458 }
459 strcpy(name, XATTR_SECURITY_PREFIX);
460 strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
461 err = btrfs_setxattr(trans, inode, name, xattr->value,
462 xattr->value_len, 0);
463 kfree(name);
464 if (err < 0)
465 break;
466 }
467 memalloc_nofs_restore(nofs_flag);
468 return err;
469}
470
471int btrfs_xattr_security_init(struct btrfs_trans_handle *trans,
472 struct inode *inode, struct inode *dir,
473 const struct qstr *qstr)
474{
475 return security_inode_init_security(inode, dir, qstr,
476 &btrfs_initxattrs, trans);
477}