Line data Source code
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 :
27 2706977 : int btrfs_getxattr(struct inode *inode, const char *name,
28 : void *buffer, size_t size)
29 : {
30 2706977 : struct btrfs_dir_item *di;
31 2706977 : struct btrfs_root *root = BTRFS_I(inode)->root;
32 2706977 : struct btrfs_path *path;
33 2706977 : struct extent_buffer *leaf;
34 2706977 : int ret = 0;
35 2706977 : unsigned long data_ptr;
36 :
37 2706977 : path = btrfs_alloc_path();
38 2712258 : if (!path)
39 : return -ENOMEM;
40 :
41 : /* lookup the xattr by name */
42 5424516 : di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(BTRFS_I(inode)),
43 : name, strlen(name), 0);
44 2716294 : if (!di) {
45 2667683 : ret = -ENODATA;
46 2667683 : goto out;
47 48611 : } else if (IS_ERR(di)) {
48 0 : ret = PTR_ERR(di);
49 0 : goto out;
50 : }
51 :
52 48611 : leaf = path->nodes[0];
53 : /* if size is 0, that means we want the size of the attr */
54 48611 : if (!size) {
55 24486 : ret = btrfs_dir_data_len(leaf, di);
56 24485 : goto out;
57 : }
58 :
59 : /* now get the data out of our dir_item */
60 24125 : if (btrfs_dir_data_len(leaf, di) > size) {
61 0 : ret = -ERANGE;
62 0 : 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 24126 : data_ptr = (unsigned long)((char *)(di + 1) +
73 24126 : btrfs_dir_name_len(leaf, di));
74 24126 : read_extent_buffer(leaf, buffer, data_ptr,
75 : btrfs_dir_data_len(leaf, di));
76 24127 : ret = btrfs_dir_data_len(leaf, di);
77 :
78 2716295 : out:
79 2716295 : btrfs_free_path(path);
80 2716295 : return ret;
81 : }
82 :
83 1420665 : int btrfs_setxattr(struct btrfs_trans_handle *trans, struct inode *inode,
84 : const char *name, const void *value, size_t size, int flags)
85 : {
86 1420665 : struct btrfs_dir_item *di = NULL;
87 1420665 : struct btrfs_root *root = BTRFS_I(inode)->root;
88 1420665 : struct btrfs_fs_info *fs_info = root->fs_info;
89 1420665 : struct btrfs_path *path;
90 1420665 : size_t name_len = strlen(name);
91 1420665 : int ret = 0;
92 :
93 1420665 : ASSERT(trans);
94 :
95 1420665 : if (name_len + size > BTRFS_MAX_XATTR_SIZE(root->fs_info))
96 : return -ENOSPC;
97 :
98 1420601 : path = btrfs_alloc_path();
99 1420565 : if (!path)
100 : return -ENOMEM;
101 1420565 : path->skip_release_on_error = 1;
102 :
103 1420565 : if (!value) {
104 1002797 : di = btrfs_lookup_xattr(trans, root, path,
105 : btrfs_ino(BTRFS_I(inode)), name, name_len, -1);
106 1003060 : if (!di && (flags & XATTR_REPLACE))
107 : ret = -ENODATA;
108 971978 : else if (IS_ERR(di))
109 0 : ret = PTR_ERR(di);
110 971978 : else if (di)
111 44499 : ret = btrfs_delete_one_dir_name(trans, root, path, di);
112 1003059 : 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 417768 : if (flags & XATTR_REPLACE) {
123 48049 : ASSERT(inode_is_locked(inode));
124 48049 : di = btrfs_lookup_xattr(NULL, root, path,
125 : btrfs_ino(BTRFS_I(inode)), name, name_len, 0);
126 48046 : if (!di)
127 : ret = -ENODATA;
128 28937 : else if (IS_ERR(di))
129 0 : ret = PTR_ERR(di);
130 0 : if (ret)
131 19109 : goto out;
132 28937 : btrfs_release_path(path);
133 28937 : di = NULL;
134 : }
135 :
136 398658 : ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(BTRFS_I(inode)),
137 : name, name_len, value, size);
138 398693 : 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 0 : ret = 0;
145 0 : btrfs_assert_tree_write_locked(path->nodes[0]);
146 0 : di = btrfs_match_dir_item_name(fs_info, path, name, name_len);
147 0 : if (!di && !(flags & XATTR_REPLACE)) {
148 0 : ret = -ENOSPC;
149 0 : goto out;
150 : }
151 398693 : } else if (ret == -EEXIST) {
152 61566 : ret = 0;
153 61566 : di = btrfs_match_dir_item_name(fs_info, path, name, name_len);
154 61566 : ASSERT(di); /* logic error */
155 337127 : } else if (ret) {
156 0 : goto out;
157 : }
158 :
159 61564 : if (di && (flags & XATTR_CREATE)) {
160 148 : ret = -EEXIST;
161 148 : goto out;
162 : }
163 :
164 398543 : 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 61415 : const int slot = path->slots[0];
173 61415 : struct extent_buffer *leaf = path->nodes[0];
174 61415 : const u16 old_data_len = btrfs_dir_data_len(leaf, di);
175 61414 : const u32 item_size = btrfs_item_size(leaf, slot);
176 61419 : const u32 data_size = sizeof(*di) + name_len + size;
177 61419 : unsigned long data_ptr;
178 61419 : char *ptr;
179 :
180 61419 : if (size > old_data_len) {
181 30454 : if (btrfs_leaf_free_space(leaf) <
182 30455 : (size - old_data_len)) {
183 0 : ret = -ENOSPC;
184 0 : goto out;
185 : }
186 : }
187 :
188 61420 : if (old_data_len + name_len + sizeof(*di) == item_size) {
189 : /* No other xattrs packed in the same leaf item. */
190 61420 : if (size > old_data_len)
191 30454 : btrfs_extend_item(path, size - old_data_len);
192 30966 : else if (size < old_data_len)
193 30302 : btrfs_truncate_item(path, data_size, 1);
194 : } else {
195 : /* There are other xattrs packed in the same item. */
196 0 : ret = btrfs_delete_one_dir_name(trans, root, path, di);
197 0 : if (ret)
198 0 : goto out;
199 0 : btrfs_extend_item(path, data_size);
200 : }
201 :
202 61421 : ptr = btrfs_item_ptr(leaf, slot, char);
203 61417 : ptr += btrfs_item_size(leaf, slot) - data_size;
204 61418 : di = (struct btrfs_dir_item *)ptr;
205 61418 : btrfs_set_dir_data_len(leaf, di, size);
206 61418 : data_ptr = ((unsigned long)(di + 1)) + name_len;
207 61418 : write_extent_buffer(leaf, value, data_ptr, size);
208 61410 : btrfs_mark_buffer_dirty(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 1420862 : }
216 337128 : out:
217 1420862 : btrfs_free_path(path);
218 1420876 : if (!ret) {
219 1370500 : set_bit(BTRFS_INODE_COPY_EVERYTHING,
220 1370500 : &BTRFS_I(inode)->runtime_flags);
221 1370529 : 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 : */
229 1402368 : int btrfs_setxattr_trans(struct inode *inode, const char *name,
230 : const void *value, size_t size, int flags)
231 : {
232 1402368 : struct btrfs_root *root = BTRFS_I(inode)->root;
233 1402368 : struct btrfs_trans_handle *trans;
234 1402368 : const bool start_trans = (current->journal_info == NULL);
235 1402368 : int ret;
236 :
237 1402368 : if (start_trans) {
238 : /*
239 : * 1 unit for inserting/updating/deleting the xattr
240 : * 1 unit for the inode item update
241 : */
242 1402368 : trans = btrfs_start_transaction(root, 2);
243 1409333 : if (IS_ERR(trans))
244 23454 : 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 0 : ASSERT(strncmp(name, XATTR_SECURITY_PREFIX,
258 : XATTR_SECURITY_PREFIX_LEN) == 0);
259 0 : trans = current->journal_info;
260 : }
261 :
262 1385879 : ret = btrfs_setxattr(trans, inode, name, value, size, flags);
263 1386090 : if (ret)
264 50403 : goto out;
265 :
266 1335687 : inode_inc_iversion(inode);
267 1335682 : inode->i_ctime = current_time(inode);
268 1335538 : ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
269 1335745 : if (ret)
270 0 : btrfs_abort_transaction(trans, ret);
271 1335745 : out:
272 1386148 : if (start_trans)
273 1386105 : btrfs_end_transaction(trans);
274 : return ret;
275 : }
276 :
277 145399 : ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
278 : {
279 145399 : struct btrfs_key found_key;
280 145399 : struct btrfs_key key;
281 145399 : struct inode *inode = d_inode(dentry);
282 145399 : struct btrfs_root *root = BTRFS_I(inode)->root;
283 145399 : struct btrfs_path *path;
284 145399 : int iter_ret = 0;
285 145399 : int ret = 0;
286 145399 : 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 145399 : key.objectid = btrfs_ino(BTRFS_I(inode));
294 145399 : key.type = BTRFS_XATTR_ITEM_KEY;
295 145399 : key.offset = 0;
296 :
297 145399 : path = btrfs_alloc_path();
298 145421 : if (!path)
299 : return -ENOMEM;
300 145421 : path->reada = READA_FORWARD;
301 :
302 : /* search for our xattrs */
303 461842 : btrfs_for_each_slot(root, &key, &found_key, path, iter_ret) {
304 454723 : struct extent_buffer *leaf;
305 454723 : int slot;
306 454723 : struct btrfs_dir_item *di;
307 454723 : u32 item_size;
308 454723 : u32 cur;
309 :
310 454723 : leaf = path->nodes[0];
311 454723 : slot = path->slots[0];
312 :
313 : /* check to make sure this item is what we want */
314 454723 : if (found_key.objectid != key.objectid)
315 : break;
316 387587 : if (found_key.type > BTRFS_XATTR_ITEM_KEY)
317 : break;
318 316524 : if (found_key.type < BTRFS_XATTR_ITEM_KEY)
319 0 : continue;
320 :
321 316524 : di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
322 316472 : item_size = btrfs_item_size(leaf, slot);
323 316472 : cur = 0;
324 632990 : while (cur < item_size) {
325 316556 : u16 name_len = btrfs_dir_name_len(leaf, di);
326 316488 : u16 data_len = btrfs_dir_data_len(leaf, di);
327 316544 : u32 this_len = sizeof(*di) + name_len + data_len;
328 316544 : unsigned long name_ptr = (unsigned long)(di + 1);
329 :
330 316544 : total_size += name_len + 1;
331 : /*
332 : * We are just looking for how big our buffer needs to
333 : * be.
334 : */
335 316544 : if (!size)
336 96691 : goto next;
337 :
338 219853 : if (!buffer || (name_len + 1) > size_left) {
339 : iter_ret = -ERANGE;
340 : break;
341 : }
342 :
343 219849 : read_extent_buffer(leaf, buffer, name_ptr, name_len);
344 219827 : buffer[name_len] = '\0';
345 :
346 219827 : size_left -= name_len + 1;
347 219827 : buffer += name_len + 1;
348 316518 : next:
349 316518 : cur += this_len;
350 316518 : di = (struct btrfs_dir_item *)((char *)di + this_len);
351 : }
352 : }
353 :
354 145449 : if (iter_ret < 0)
355 : ret = iter_ret;
356 : else
357 145436 : ret = total_size;
358 :
359 145449 : btrfs_free_path(path);
360 :
361 145456 : return ret;
362 : }
363 :
364 2713764 : static 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 2713764 : name = xattr_full_name(handler, name);
369 2711353 : return btrfs_getxattr(inode, name, buffer, size);
370 : }
371 :
372 481588 : static 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 481588 : if (btrfs_root_readonly(BTRFS_I(inode)->root))
379 : return -EROFS;
380 :
381 481584 : name = xattr_full_name(handler, name);
382 481468 : return btrfs_setxattr_trans(inode, name, buffer, size, flags);
383 : }
384 :
385 40 : static int btrfs_xattr_handler_set_prop(const struct xattr_handler *handler,
386 : struct mnt_idmap *idmap,
387 : struct dentry *unused, struct inode *inode,
388 : const char *name, const void *value,
389 : size_t size, int flags)
390 : {
391 40 : int ret;
392 40 : struct btrfs_trans_handle *trans;
393 40 : struct btrfs_root *root = BTRFS_I(inode)->root;
394 :
395 40 : name = xattr_full_name(handler, name);
396 40 : ret = btrfs_validate_prop(BTRFS_I(inode), name, value, size);
397 40 : if (ret)
398 : return ret;
399 :
400 26 : if (btrfs_ignore_prop(BTRFS_I(inode), name))
401 : return 0;
402 :
403 26 : trans = btrfs_start_transaction(root, 2);
404 26 : if (IS_ERR(trans))
405 0 : return PTR_ERR(trans);
406 :
407 26 : ret = btrfs_set_prop(trans, inode, name, value, size, flags);
408 26 : if (!ret) {
409 26 : inode_inc_iversion(inode);
410 26 : inode->i_ctime = current_time(inode);
411 26 : ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
412 26 : if (ret)
413 0 : btrfs_abort_transaction(trans, ret);
414 : }
415 :
416 26 : btrfs_end_transaction(trans);
417 :
418 26 : return ret;
419 : }
420 :
421 : static const struct xattr_handler btrfs_security_xattr_handler = {
422 : .prefix = XATTR_SECURITY_PREFIX,
423 : .get = btrfs_xattr_handler_get,
424 : .set = btrfs_xattr_handler_set,
425 : };
426 :
427 : static const struct xattr_handler btrfs_trusted_xattr_handler = {
428 : .prefix = XATTR_TRUSTED_PREFIX,
429 : .get = btrfs_xattr_handler_get,
430 : .set = btrfs_xattr_handler_set,
431 : };
432 :
433 : static const struct xattr_handler btrfs_user_xattr_handler = {
434 : .prefix = XATTR_USER_PREFIX,
435 : .get = btrfs_xattr_handler_get,
436 : .set = btrfs_xattr_handler_set,
437 : };
438 :
439 : static const struct xattr_handler btrfs_btrfs_xattr_handler = {
440 : .prefix = XATTR_BTRFS_PREFIX,
441 : .get = btrfs_xattr_handler_get,
442 : .set = btrfs_xattr_handler_set_prop,
443 : };
444 :
445 : const struct xattr_handler *btrfs_xattr_handlers[] = {
446 : &btrfs_security_xattr_handler,
447 : &btrfs_trusted_xattr_handler,
448 : &btrfs_user_xattr_handler,
449 : &btrfs_btrfs_xattr_handler,
450 : NULL,
451 : };
452 :
453 : static int btrfs_initxattrs(struct inode *inode,
454 : const struct xattr *xattr_array, void *fs_private)
455 : {
456 : struct btrfs_trans_handle *trans = fs_private;
457 : const struct xattr *xattr;
458 : unsigned int nofs_flag;
459 : char *name;
460 : int err = 0;
461 :
462 : /*
463 : * We're holding a transaction handle, so use a NOFS memory allocation
464 : * context to avoid deadlock if reclaim happens.
465 : */
466 : nofs_flag = memalloc_nofs_save();
467 : for (xattr = xattr_array; xattr->name != NULL; xattr++) {
468 : name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
469 : strlen(xattr->name) + 1, GFP_KERNEL);
470 : if (!name) {
471 : err = -ENOMEM;
472 : break;
473 : }
474 : strcpy(name, XATTR_SECURITY_PREFIX);
475 : strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
476 : err = btrfs_setxattr(trans, inode, name, xattr->value,
477 : xattr->value_len, 0);
478 : kfree(name);
479 : if (err < 0)
480 : break;
481 : }
482 : memalloc_nofs_restore(nofs_flag);
483 : return err;
484 : }
485 :
486 3254924 : int btrfs_xattr_security_init(struct btrfs_trans_handle *trans,
487 : struct inode *inode, struct inode *dir,
488 : const struct qstr *qstr)
489 : {
490 3254924 : return security_inode_init_security(inode, dir, qstr,
491 : &btrfs_initxattrs, trans);
492 : }
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