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5103e947 JB |
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> | |
0279b4cd | 24 | #include <linux/security.h> |
996a710d | 25 | #include <linux/posix_acl_xattr.h> |
ae5e165d | 26 | #include <linux/iversion.h> |
5103e947 JB |
27 | #include "ctree.h" |
28 | #include "btrfs_inode.h" | |
29 | #include "transaction.h" | |
30 | #include "xattr.h" | |
31 | #include "disk-io.h" | |
63541927 | 32 | #include "props.h" |
5f5bc6b1 | 33 | #include "locking.h" |
33268eaf | 34 | |
5103e947 | 35 | |
95819c05 CH |
36 | ssize_t __btrfs_getxattr(struct inode *inode, const char *name, |
37 | void *buffer, size_t size) | |
5103e947 JB |
38 | { |
39 | struct btrfs_dir_item *di; | |
40 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
41 | struct btrfs_path *path; | |
42 | struct extent_buffer *leaf; | |
5103e947 JB |
43 | int ret = 0; |
44 | unsigned long data_ptr; | |
5103e947 JB |
45 | |
46 | path = btrfs_alloc_path(); | |
95819c05 | 47 | if (!path) |
5103e947 | 48 | return -ENOMEM; |
5103e947 | 49 | |
5103e947 | 50 | /* lookup the xattr by name */ |
f85b7379 DS |
51 | di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(BTRFS_I(inode)), |
52 | name, strlen(name), 0); | |
07060404 | 53 | if (!di) { |
5103e947 JB |
54 | ret = -ENODATA; |
55 | goto out; | |
07060404 JB |
56 | } else if (IS_ERR(di)) { |
57 | ret = PTR_ERR(di); | |
58 | goto out; | |
5103e947 JB |
59 | } |
60 | ||
61 | leaf = path->nodes[0]; | |
62 | /* if size is 0, that means we want the size of the attr */ | |
63 | if (!size) { | |
64 | ret = btrfs_dir_data_len(leaf, di); | |
65 | goto out; | |
66 | } | |
67 | ||
68 | /* now get the data out of our dir_item */ | |
69 | if (btrfs_dir_data_len(leaf, di) > size) { | |
70 | ret = -ERANGE; | |
71 | goto out; | |
72 | } | |
07060404 JB |
73 | |
74 | /* | |
75 | * The way things are packed into the leaf is like this | |
76 | * |struct btrfs_dir_item|name|data| | |
77 | * where name is the xattr name, so security.foo, and data is the | |
78 | * content of the xattr. data_ptr points to the location in memory | |
79 | * where the data starts in the in memory leaf | |
80 | */ | |
5103e947 JB |
81 | data_ptr = (unsigned long)((char *)(di + 1) + |
82 | btrfs_dir_name_len(leaf, di)); | |
83 | read_extent_buffer(leaf, buffer, data_ptr, | |
3acd7ee8 | 84 | btrfs_dir_data_len(leaf, di)); |
5103e947 JB |
85 | ret = btrfs_dir_data_len(leaf, di); |
86 | ||
87 | out: | |
5103e947 JB |
88 | btrfs_free_path(path); |
89 | return ret; | |
90 | } | |
91 | ||
f34f57a3 YZ |
92 | static int do_setxattr(struct btrfs_trans_handle *trans, |
93 | struct inode *inode, const char *name, | |
94 | const void *value, size_t size, int flags) | |
5103e947 | 95 | { |
5f5bc6b1 | 96 | struct btrfs_dir_item *di = NULL; |
5103e947 | 97 | struct btrfs_root *root = BTRFS_I(inode)->root; |
2ff7e61e | 98 | struct btrfs_fs_info *fs_info = root->fs_info; |
5103e947 | 99 | struct btrfs_path *path; |
f34f57a3 YZ |
100 | size_t name_len = strlen(name); |
101 | int ret = 0; | |
102 | ||
da17066c | 103 | if (name_len + size > BTRFS_MAX_XATTR_SIZE(root->fs_info)) |
f34f57a3 | 104 | return -ENOSPC; |
5103e947 JB |
105 | |
106 | path = btrfs_alloc_path(); | |
95819c05 | 107 | if (!path) |
5103e947 | 108 | return -ENOMEM; |
5f5bc6b1 FM |
109 | path->skip_release_on_error = 1; |
110 | ||
111 | if (!value) { | |
f85b7379 DS |
112 | di = btrfs_lookup_xattr(trans, root, path, |
113 | btrfs_ino(BTRFS_I(inode)), name, name_len, -1); | |
5f5bc6b1 FM |
114 | if (!di && (flags & XATTR_REPLACE)) |
115 | ret = -ENODATA; | |
5cdf83ed FM |
116 | else if (IS_ERR(di)) |
117 | ret = PTR_ERR(di); | |
5f5bc6b1 FM |
118 | else if (di) |
119 | ret = btrfs_delete_one_dir_name(trans, root, path, di); | |
120 | goto out; | |
121 | } | |
5103e947 | 122 | |
5f5bc6b1 FM |
123 | /* |
124 | * For a replace we can't just do the insert blindly. | |
125 | * Do a lookup first (read-only btrfs_search_slot), and return if xattr | |
126 | * doesn't exist. If it exists, fall down below to the insert/replace | |
127 | * path - we can't race with a concurrent xattr delete, because the VFS | |
128 | * locks the inode's i_mutex before calling setxattr or removexattr. | |
129 | */ | |
fa09200b | 130 | if (flags & XATTR_REPLACE) { |
5955102c | 131 | ASSERT(inode_is_locked(inode)); |
f85b7379 DS |
132 | di = btrfs_lookup_xattr(NULL, root, path, |
133 | btrfs_ino(BTRFS_I(inode)), name, name_len, 0); | |
5cdf83ed | 134 | if (!di) |
fa09200b | 135 | ret = -ENODATA; |
5cdf83ed FM |
136 | else if (IS_ERR(di)) |
137 | ret = PTR_ERR(di); | |
138 | if (ret) | |
5103e947 | 139 | goto out; |
b3b4aa74 | 140 | btrfs_release_path(path); |
5f5bc6b1 FM |
141 | di = NULL; |
142 | } | |
4815053a | 143 | |
4a0cc7ca | 144 | ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(BTRFS_I(inode)), |
5f5bc6b1 FM |
145 | name, name_len, value, size); |
146 | if (ret == -EOVERFLOW) { | |
4815053a | 147 | /* |
5f5bc6b1 FM |
148 | * We have an existing item in a leaf, split_leaf couldn't |
149 | * expand it. That item might have or not a dir_item that | |
150 | * matches our target xattr, so lets check. | |
4815053a | 151 | */ |
5f5bc6b1 FM |
152 | ret = 0; |
153 | btrfs_assert_tree_locked(path->nodes[0]); | |
2ff7e61e | 154 | di = btrfs_match_dir_item_name(fs_info, path, name, name_len); |
5f5bc6b1 FM |
155 | if (!di && !(flags & XATTR_REPLACE)) { |
156 | ret = -ENOSPC; | |
01e6deb2 LB |
157 | goto out; |
158 | } | |
5f5bc6b1 FM |
159 | } else if (ret == -EEXIST) { |
160 | ret = 0; | |
2ff7e61e | 161 | di = btrfs_match_dir_item_name(fs_info, path, name, name_len); |
5f5bc6b1 FM |
162 | ASSERT(di); /* logic error */ |
163 | } else if (ret) { | |
164 | goto out; | |
fa09200b | 165 | } |
5103e947 | 166 | |
5f5bc6b1 | 167 | if (di && (flags & XATTR_CREATE)) { |
ed3ee9f4 | 168 | ret = -EEXIST; |
5f5bc6b1 FM |
169 | goto out; |
170 | } | |
ed3ee9f4 | 171 | |
5f5bc6b1 | 172 | if (di) { |
fa09200b | 173 | /* |
5f5bc6b1 FM |
174 | * We're doing a replace, and it must be atomic, that is, at |
175 | * any point in time we have either the old or the new xattr | |
176 | * value in the tree. We don't want readers (getxattr and | |
177 | * listxattrs) to miss a value, this is specially important | |
178 | * for ACLs. | |
fa09200b | 179 | */ |
5f5bc6b1 FM |
180 | const int slot = path->slots[0]; |
181 | struct extent_buffer *leaf = path->nodes[0]; | |
182 | const u16 old_data_len = btrfs_dir_data_len(leaf, di); | |
183 | const u32 item_size = btrfs_item_size_nr(leaf, slot); | |
184 | const u32 data_size = sizeof(*di) + name_len + size; | |
185 | struct btrfs_item *item; | |
186 | unsigned long data_ptr; | |
187 | char *ptr; | |
188 | ||
189 | if (size > old_data_len) { | |
2ff7e61e | 190 | if (btrfs_leaf_free_space(fs_info, leaf) < |
5f5bc6b1 FM |
191 | (size - old_data_len)) { |
192 | ret = -ENOSPC; | |
193 | goto out; | |
194 | } | |
fa09200b | 195 | } |
33268eaf | 196 | |
5f5bc6b1 FM |
197 | if (old_data_len + name_len + sizeof(*di) == item_size) { |
198 | /* No other xattrs packed in the same leaf item. */ | |
199 | if (size > old_data_len) | |
2ff7e61e | 200 | btrfs_extend_item(fs_info, path, |
5f5bc6b1 FM |
201 | size - old_data_len); |
202 | else if (size < old_data_len) | |
2ff7e61e JM |
203 | btrfs_truncate_item(fs_info, path, |
204 | data_size, 1); | |
5f5bc6b1 FM |
205 | } else { |
206 | /* There are other xattrs packed in the same item. */ | |
207 | ret = btrfs_delete_one_dir_name(trans, root, path, di); | |
208 | if (ret) | |
209 | goto out; | |
2ff7e61e | 210 | btrfs_extend_item(fs_info, path, data_size); |
5f5bc6b1 | 211 | } |
fa09200b | 212 | |
5f5bc6b1 FM |
213 | item = btrfs_item_nr(slot); |
214 | ptr = btrfs_item_ptr(leaf, slot, char); | |
215 | ptr += btrfs_item_size(leaf, item) - data_size; | |
216 | di = (struct btrfs_dir_item *)ptr; | |
217 | btrfs_set_dir_data_len(leaf, di, size); | |
218 | data_ptr = ((unsigned long)(di + 1)) + name_len; | |
219 | write_extent_buffer(leaf, value, data_ptr, size); | |
220 | btrfs_mark_buffer_dirty(leaf); | |
221 | } else { | |
fa09200b | 222 | /* |
5f5bc6b1 FM |
223 | * Insert, and we had space for the xattr, so path->slots[0] is |
224 | * where our xattr dir_item is and btrfs_insert_xattr_item() | |
225 | * filled it. | |
fa09200b | 226 | */ |
5103e947 | 227 | } |
f34f57a3 YZ |
228 | out: |
229 | btrfs_free_path(path); | |
230 | return ret; | |
231 | } | |
232 | ||
4815053a DS |
233 | /* |
234 | * @value: "" makes the attribute to empty, NULL removes it | |
235 | */ | |
f34f57a3 YZ |
236 | int __btrfs_setxattr(struct btrfs_trans_handle *trans, |
237 | struct inode *inode, const char *name, | |
238 | const void *value, size_t size, int flags) | |
239 | { | |
240 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
241 | int ret; | |
242 | ||
e0d46f5c AG |
243 | if (btrfs_root_readonly(root)) |
244 | return -EROFS; | |
245 | ||
f34f57a3 YZ |
246 | if (trans) |
247 | return do_setxattr(trans, inode, name, value, size, flags); | |
248 | ||
a22285a6 YZ |
249 | trans = btrfs_start_transaction(root, 2); |
250 | if (IS_ERR(trans)) | |
251 | return PTR_ERR(trans); | |
5103e947 | 252 | |
f34f57a3 YZ |
253 | ret = do_setxattr(trans, inode, name, value, size, flags); |
254 | if (ret) | |
255 | goto out; | |
256 | ||
0c4d2d95 | 257 | inode_inc_iversion(inode); |
c2050a45 | 258 | inode->i_ctime = current_time(inode); |
e9976151 | 259 | set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags); |
f34f57a3 YZ |
260 | ret = btrfs_update_inode(trans, root, inode); |
261 | BUG_ON(ret); | |
262 | out: | |
3a45bb20 | 263 | btrfs_end_transaction(trans); |
5103e947 JB |
264 | return ret; |
265 | } | |
266 | ||
267 | ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size) | |
268 | { | |
daac7ba6 | 269 | struct btrfs_key key; |
2b0143b5 | 270 | struct inode *inode = d_inode(dentry); |
5103e947 JB |
271 | struct btrfs_root *root = BTRFS_I(inode)->root; |
272 | struct btrfs_path *path; | |
daac7ba6 | 273 | int ret = 0; |
eaa47d86 | 274 | size_t total_size = 0, size_left = size; |
5103e947 JB |
275 | |
276 | /* | |
277 | * ok we want all objects associated with this id. | |
278 | * NOTE: we set key.offset = 0; because we want to start with the | |
279 | * first xattr that we find and walk forward | |
280 | */ | |
4a0cc7ca | 281 | key.objectid = btrfs_ino(BTRFS_I(inode)); |
962a298f | 282 | key.type = BTRFS_XATTR_ITEM_KEY; |
5103e947 JB |
283 | key.offset = 0; |
284 | ||
285 | path = btrfs_alloc_path(); | |
5103e947 JB |
286 | if (!path) |
287 | return -ENOMEM; | |
e4058b54 | 288 | path->reada = READA_FORWARD; |
5103e947 | 289 | |
5103e947 JB |
290 | /* search for our xattrs */ |
291 | ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); | |
292 | if (ret < 0) | |
293 | goto err; | |
2e6a0035 | 294 | |
5103e947 | 295 | while (1) { |
daac7ba6 FM |
296 | struct extent_buffer *leaf; |
297 | int slot; | |
298 | struct btrfs_dir_item *di; | |
299 | struct btrfs_key found_key; | |
300 | u32 item_size; | |
301 | u32 cur; | |
302 | ||
5103e947 | 303 | leaf = path->nodes[0]; |
5103e947 JB |
304 | slot = path->slots[0]; |
305 | ||
306 | /* this is where we start walking through the path */ | |
2e6a0035 | 307 | if (slot >= btrfs_header_nritems(leaf)) { |
5103e947 JB |
308 | /* |
309 | * if we've reached the last slot in this leaf we need | |
310 | * to go to the next leaf and reset everything | |
311 | */ | |
2e6a0035 LZ |
312 | ret = btrfs_next_leaf(root, path); |
313 | if (ret < 0) | |
314 | goto err; | |
315 | else if (ret > 0) | |
316 | break; | |
317 | continue; | |
5103e947 | 318 | } |
5103e947 | 319 | |
5103e947 JB |
320 | btrfs_item_key_to_cpu(leaf, &found_key, slot); |
321 | ||
322 | /* check to make sure this item is what we want */ | |
323 | if (found_key.objectid != key.objectid) | |
324 | break; | |
f1cd1f0b | 325 | if (found_key.type > BTRFS_XATTR_ITEM_KEY) |
5103e947 | 326 | break; |
f1cd1f0b | 327 | if (found_key.type < BTRFS_XATTR_ITEM_KEY) |
daac7ba6 | 328 | goto next_item; |
5103e947 JB |
329 | |
330 | di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item); | |
daac7ba6 FM |
331 | item_size = btrfs_item_size_nr(leaf, slot); |
332 | cur = 0; | |
333 | while (cur < item_size) { | |
334 | u16 name_len = btrfs_dir_name_len(leaf, di); | |
335 | u16 data_len = btrfs_dir_data_len(leaf, di); | |
336 | u32 this_len = sizeof(*di) + name_len + data_len; | |
337 | unsigned long name_ptr = (unsigned long)(di + 1); | |
338 | ||
daac7ba6 FM |
339 | total_size += name_len + 1; |
340 | /* | |
341 | * We are just looking for how big our buffer needs to | |
342 | * be. | |
343 | */ | |
344 | if (!size) | |
345 | goto next; | |
5103e947 | 346 | |
daac7ba6 FM |
347 | if (!buffer || (name_len + 1) > size_left) { |
348 | ret = -ERANGE; | |
349 | goto err; | |
350 | } | |
5103e947 | 351 | |
daac7ba6 FM |
352 | read_extent_buffer(leaf, buffer, name_ptr, name_len); |
353 | buffer[name_len] = '\0'; | |
eaa47d86 | 354 | |
daac7ba6 FM |
355 | size_left -= name_len + 1; |
356 | buffer += name_len + 1; | |
2e6a0035 | 357 | next: |
daac7ba6 FM |
358 | cur += this_len; |
359 | di = (struct btrfs_dir_item *)((char *)di + this_len); | |
360 | } | |
361 | next_item: | |
2e6a0035 | 362 | path->slots[0]++; |
5103e947 JB |
363 | } |
364 | ret = total_size; | |
365 | ||
366 | err: | |
5103e947 JB |
367 | btrfs_free_path(path); |
368 | ||
369 | return ret; | |
370 | } | |
371 | ||
9172abbc | 372 | static int btrfs_xattr_handler_get(const struct xattr_handler *handler, |
b296821a AV |
373 | struct dentry *unused, struct inode *inode, |
374 | const char *name, void *buffer, size_t size) | |
95819c05 | 375 | { |
9172abbc AG |
376 | name = xattr_full_name(handler, name); |
377 | return __btrfs_getxattr(inode, name, buffer, size); | |
69a32ac5 CM |
378 | } |
379 | ||
9172abbc | 380 | static int btrfs_xattr_handler_set(const struct xattr_handler *handler, |
59301226 AV |
381 | struct dentry *unused, struct inode *inode, |
382 | const char *name, const void *buffer, | |
383 | size_t size, int flags) | |
95819c05 | 384 | { |
9172abbc AG |
385 | name = xattr_full_name(handler, name); |
386 | return __btrfs_setxattr(NULL, inode, name, buffer, size, flags); | |
387 | } | |
5103e947 | 388 | |
9172abbc | 389 | static int btrfs_xattr_handler_set_prop(const struct xattr_handler *handler, |
59301226 | 390 | struct dentry *unused, struct inode *inode, |
9172abbc AG |
391 | const char *name, const void *value, |
392 | size_t size, int flags) | |
393 | { | |
394 | name = xattr_full_name(handler, name); | |
59301226 | 395 | return btrfs_set_prop(inode, name, value, size, flags); |
95819c05 | 396 | } |
5103e947 | 397 | |
9172abbc AG |
398 | static const struct xattr_handler btrfs_security_xattr_handler = { |
399 | .prefix = XATTR_SECURITY_PREFIX, | |
400 | .get = btrfs_xattr_handler_get, | |
401 | .set = btrfs_xattr_handler_set, | |
402 | }; | |
403 | ||
404 | static const struct xattr_handler btrfs_trusted_xattr_handler = { | |
405 | .prefix = XATTR_TRUSTED_PREFIX, | |
406 | .get = btrfs_xattr_handler_get, | |
407 | .set = btrfs_xattr_handler_set, | |
408 | }; | |
409 | ||
410 | static const struct xattr_handler btrfs_user_xattr_handler = { | |
411 | .prefix = XATTR_USER_PREFIX, | |
412 | .get = btrfs_xattr_handler_get, | |
413 | .set = btrfs_xattr_handler_set, | |
414 | }; | |
415 | ||
416 | static const struct xattr_handler btrfs_btrfs_xattr_handler = { | |
417 | .prefix = XATTR_BTRFS_PREFIX, | |
418 | .get = btrfs_xattr_handler_get, | |
419 | .set = btrfs_xattr_handler_set_prop, | |
420 | }; | |
421 | ||
422 | const struct xattr_handler *btrfs_xattr_handlers[] = { | |
423 | &btrfs_security_xattr_handler, | |
424 | #ifdef CONFIG_BTRFS_FS_POSIX_ACL | |
425 | &posix_acl_access_xattr_handler, | |
426 | &posix_acl_default_xattr_handler, | |
427 | #endif | |
428 | &btrfs_trusted_xattr_handler, | |
429 | &btrfs_user_xattr_handler, | |
430 | &btrfs_btrfs_xattr_handler, | |
431 | NULL, | |
432 | }; | |
433 | ||
48a3b636 ES |
434 | static int btrfs_initxattrs(struct inode *inode, |
435 | const struct xattr *xattr_array, void *fs_info) | |
0279b4cd | 436 | { |
9d8f13ba MZ |
437 | const struct xattr *xattr; |
438 | struct btrfs_trans_handle *trans = fs_info; | |
0279b4cd | 439 | char *name; |
9d8f13ba | 440 | int err = 0; |
0279b4cd | 441 | |
9d8f13ba MZ |
442 | for (xattr = xattr_array; xattr->name != NULL; xattr++) { |
443 | name = kmalloc(XATTR_SECURITY_PREFIX_LEN + | |
39a27ec1 | 444 | strlen(xattr->name) + 1, GFP_KERNEL); |
9d8f13ba MZ |
445 | if (!name) { |
446 | err = -ENOMEM; | |
447 | break; | |
448 | } | |
0279b4cd | 449 | strcpy(name, XATTR_SECURITY_PREFIX); |
9d8f13ba MZ |
450 | strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name); |
451 | err = __btrfs_setxattr(trans, inode, name, | |
452 | xattr->value, xattr->value_len, 0); | |
0279b4cd | 453 | kfree(name); |
9d8f13ba MZ |
454 | if (err < 0) |
455 | break; | |
0279b4cd | 456 | } |
0279b4cd JO |
457 | return err; |
458 | } | |
9d8f13ba MZ |
459 | |
460 | int btrfs_xattr_security_init(struct btrfs_trans_handle *trans, | |
461 | struct inode *inode, struct inode *dir, | |
462 | const struct qstr *qstr) | |
463 | { | |
464 | return security_inode_init_security(inode, dir, qstr, | |
465 | &btrfs_initxattrs, trans); | |
466 | } |