Commit | Line | Data |
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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> |
5103e947 JB |
26 | #include "ctree.h" |
27 | #include "btrfs_inode.h" | |
28 | #include "transaction.h" | |
29 | #include "xattr.h" | |
30 | #include "disk-io.h" | |
63541927 | 31 | #include "props.h" |
5f5bc6b1 | 32 | #include "locking.h" |
33268eaf | 33 | |
5103e947 | 34 | |
95819c05 CH |
35 | ssize_t __btrfs_getxattr(struct inode *inode, const char *name, |
36 | void *buffer, size_t size) | |
5103e947 JB |
37 | { |
38 | struct btrfs_dir_item *di; | |
39 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
40 | struct btrfs_path *path; | |
41 | struct extent_buffer *leaf; | |
5103e947 JB |
42 | int ret = 0; |
43 | unsigned long data_ptr; | |
5103e947 JB |
44 | |
45 | path = btrfs_alloc_path(); | |
95819c05 | 46 | if (!path) |
5103e947 | 47 | return -ENOMEM; |
5103e947 | 48 | |
5103e947 | 49 | /* lookup the xattr by name */ |
33345d01 | 50 | di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(inode), name, |
5103e947 | 51 | strlen(name), 0); |
07060404 | 52 | if (!di) { |
5103e947 JB |
53 | ret = -ENODATA; |
54 | goto out; | |
07060404 JB |
55 | } else if (IS_ERR(di)) { |
56 | ret = PTR_ERR(di); | |
57 | goto out; | |
5103e947 JB |
58 | } |
59 | ||
60 | leaf = path->nodes[0]; | |
61 | /* if size is 0, that means we want the size of the attr */ | |
62 | if (!size) { | |
63 | ret = btrfs_dir_data_len(leaf, di); | |
64 | goto out; | |
65 | } | |
66 | ||
67 | /* now get the data out of our dir_item */ | |
68 | if (btrfs_dir_data_len(leaf, di) > size) { | |
69 | ret = -ERANGE; | |
70 | goto out; | |
71 | } | |
07060404 JB |
72 | |
73 | /* | |
74 | * The way things are packed into the leaf is like this | |
75 | * |struct btrfs_dir_item|name|data| | |
76 | * where name is the xattr name, so security.foo, and data is the | |
77 | * content of the xattr. data_ptr points to the location in memory | |
78 | * where the data starts in the in memory leaf | |
79 | */ | |
5103e947 JB |
80 | data_ptr = (unsigned long)((char *)(di + 1) + |
81 | btrfs_dir_name_len(leaf, di)); | |
82 | read_extent_buffer(leaf, buffer, data_ptr, | |
3acd7ee8 | 83 | btrfs_dir_data_len(leaf, di)); |
5103e947 JB |
84 | ret = btrfs_dir_data_len(leaf, di); |
85 | ||
86 | out: | |
5103e947 JB |
87 | btrfs_free_path(path); |
88 | return ret; | |
89 | } | |
90 | ||
f34f57a3 YZ |
91 | static int do_setxattr(struct btrfs_trans_handle *trans, |
92 | struct inode *inode, const char *name, | |
93 | const void *value, size_t size, int flags) | |
5103e947 | 94 | { |
5f5bc6b1 | 95 | struct btrfs_dir_item *di = NULL; |
5103e947 | 96 | struct btrfs_root *root = BTRFS_I(inode)->root; |
5103e947 | 97 | struct btrfs_path *path; |
f34f57a3 YZ |
98 | size_t name_len = strlen(name); |
99 | int ret = 0; | |
100 | ||
101 | if (name_len + size > BTRFS_MAX_XATTR_SIZE(root)) | |
102 | return -ENOSPC; | |
5103e947 JB |
103 | |
104 | path = btrfs_alloc_path(); | |
95819c05 | 105 | if (!path) |
5103e947 | 106 | return -ENOMEM; |
5f5bc6b1 FM |
107 | path->skip_release_on_error = 1; |
108 | ||
109 | if (!value) { | |
110 | di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(inode), | |
111 | name, name_len, -1); | |
112 | if (!di && (flags & XATTR_REPLACE)) | |
113 | ret = -ENODATA; | |
114 | else if (di) | |
115 | ret = btrfs_delete_one_dir_name(trans, root, path, di); | |
116 | goto out; | |
117 | } | |
5103e947 | 118 | |
5f5bc6b1 FM |
119 | /* |
120 | * For a replace we can't just do the insert blindly. | |
121 | * Do a lookup first (read-only btrfs_search_slot), and return if xattr | |
122 | * doesn't exist. If it exists, fall down below to the insert/replace | |
123 | * path - we can't race with a concurrent xattr delete, because the VFS | |
124 | * locks the inode's i_mutex before calling setxattr or removexattr. | |
125 | */ | |
fa09200b | 126 | if (flags & XATTR_REPLACE) { |
5f5bc6b1 FM |
127 | ASSERT(mutex_is_locked(&inode->i_mutex)); |
128 | di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(inode), | |
129 | name, name_len, 0); | |
130 | if (!di) { | |
fa09200b | 131 | ret = -ENODATA; |
5103e947 JB |
132 | goto out; |
133 | } | |
b3b4aa74 | 134 | btrfs_release_path(path); |
5f5bc6b1 FM |
135 | di = NULL; |
136 | } | |
4815053a | 137 | |
5f5bc6b1 FM |
138 | ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(inode), |
139 | name, name_len, value, size); | |
140 | if (ret == -EOVERFLOW) { | |
4815053a | 141 | /* |
5f5bc6b1 FM |
142 | * We have an existing item in a leaf, split_leaf couldn't |
143 | * expand it. That item might have or not a dir_item that | |
144 | * matches our target xattr, so lets check. | |
4815053a | 145 | */ |
5f5bc6b1 FM |
146 | ret = 0; |
147 | btrfs_assert_tree_locked(path->nodes[0]); | |
148 | di = btrfs_match_dir_item_name(root, path, name, name_len); | |
149 | if (!di && !(flags & XATTR_REPLACE)) { | |
150 | ret = -ENOSPC; | |
01e6deb2 LB |
151 | goto out; |
152 | } | |
5f5bc6b1 FM |
153 | } else if (ret == -EEXIST) { |
154 | ret = 0; | |
155 | di = btrfs_match_dir_item_name(root, path, name, name_len); | |
156 | ASSERT(di); /* logic error */ | |
157 | } else if (ret) { | |
158 | goto out; | |
fa09200b | 159 | } |
5103e947 | 160 | |
5f5bc6b1 | 161 | if (di && (flags & XATTR_CREATE)) { |
ed3ee9f4 | 162 | ret = -EEXIST; |
5f5bc6b1 FM |
163 | goto out; |
164 | } | |
ed3ee9f4 | 165 | |
5f5bc6b1 | 166 | if (di) { |
fa09200b | 167 | /* |
5f5bc6b1 FM |
168 | * We're doing a replace, and it must be atomic, that is, at |
169 | * any point in time we have either the old or the new xattr | |
170 | * value in the tree. We don't want readers (getxattr and | |
171 | * listxattrs) to miss a value, this is specially important | |
172 | * for ACLs. | |
fa09200b | 173 | */ |
5f5bc6b1 FM |
174 | const int slot = path->slots[0]; |
175 | struct extent_buffer *leaf = path->nodes[0]; | |
176 | const u16 old_data_len = btrfs_dir_data_len(leaf, di); | |
177 | const u32 item_size = btrfs_item_size_nr(leaf, slot); | |
178 | const u32 data_size = sizeof(*di) + name_len + size; | |
179 | struct btrfs_item *item; | |
180 | unsigned long data_ptr; | |
181 | char *ptr; | |
182 | ||
183 | if (size > old_data_len) { | |
184 | if (btrfs_leaf_free_space(root, leaf) < | |
185 | (size - old_data_len)) { | |
186 | ret = -ENOSPC; | |
187 | goto out; | |
188 | } | |
fa09200b | 189 | } |
33268eaf | 190 | |
5f5bc6b1 FM |
191 | if (old_data_len + name_len + sizeof(*di) == item_size) { |
192 | /* No other xattrs packed in the same leaf item. */ | |
193 | if (size > old_data_len) | |
194 | btrfs_extend_item(root, path, | |
195 | size - old_data_len); | |
196 | else if (size < old_data_len) | |
197 | btrfs_truncate_item(root, path, data_size, 1); | |
198 | } else { | |
199 | /* There are other xattrs packed in the same item. */ | |
200 | ret = btrfs_delete_one_dir_name(trans, root, path, di); | |
201 | if (ret) | |
202 | goto out; | |
203 | btrfs_extend_item(root, path, data_size); | |
204 | } | |
fa09200b | 205 | |
5f5bc6b1 FM |
206 | item = btrfs_item_nr(slot); |
207 | ptr = btrfs_item_ptr(leaf, slot, char); | |
208 | ptr += btrfs_item_size(leaf, item) - data_size; | |
209 | di = (struct btrfs_dir_item *)ptr; | |
210 | btrfs_set_dir_data_len(leaf, di, size); | |
211 | data_ptr = ((unsigned long)(di + 1)) + name_len; | |
212 | write_extent_buffer(leaf, value, data_ptr, size); | |
213 | btrfs_mark_buffer_dirty(leaf); | |
214 | } else { | |
fa09200b | 215 | /* |
5f5bc6b1 FM |
216 | * Insert, and we had space for the xattr, so path->slots[0] is |
217 | * where our xattr dir_item is and btrfs_insert_xattr_item() | |
218 | * filled it. | |
fa09200b | 219 | */ |
5103e947 | 220 | } |
f34f57a3 YZ |
221 | out: |
222 | btrfs_free_path(path); | |
223 | return ret; | |
224 | } | |
225 | ||
4815053a DS |
226 | /* |
227 | * @value: "" makes the attribute to empty, NULL removes it | |
228 | */ | |
f34f57a3 YZ |
229 | int __btrfs_setxattr(struct btrfs_trans_handle *trans, |
230 | struct inode *inode, const char *name, | |
231 | const void *value, size_t size, int flags) | |
232 | { | |
233 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
234 | int ret; | |
235 | ||
236 | if (trans) | |
237 | return do_setxattr(trans, inode, name, value, size, flags); | |
238 | ||
a22285a6 YZ |
239 | trans = btrfs_start_transaction(root, 2); |
240 | if (IS_ERR(trans)) | |
241 | return PTR_ERR(trans); | |
5103e947 | 242 | |
f34f57a3 YZ |
243 | ret = do_setxattr(trans, inode, name, value, size, flags); |
244 | if (ret) | |
245 | goto out; | |
246 | ||
0c4d2d95 | 247 | inode_inc_iversion(inode); |
f34f57a3 | 248 | inode->i_ctime = CURRENT_TIME; |
e9976151 | 249 | set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags); |
f34f57a3 YZ |
250 | ret = btrfs_update_inode(trans, root, inode); |
251 | BUG_ON(ret); | |
252 | out: | |
7ad85bb7 | 253 | btrfs_end_transaction(trans, root); |
5103e947 JB |
254 | return ret; |
255 | } | |
256 | ||
257 | ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size) | |
258 | { | |
259 | struct btrfs_key key, found_key; | |
260 | struct inode *inode = dentry->d_inode; | |
261 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
262 | struct btrfs_path *path; | |
5103e947 JB |
263 | struct extent_buffer *leaf; |
264 | struct btrfs_dir_item *di; | |
2e6a0035 | 265 | int ret = 0, slot; |
eaa47d86 | 266 | size_t total_size = 0, size_left = size; |
5103e947 | 267 | unsigned long name_ptr; |
eaa47d86 | 268 | size_t name_len; |
5103e947 JB |
269 | |
270 | /* | |
271 | * ok we want all objects associated with this id. | |
272 | * NOTE: we set key.offset = 0; because we want to start with the | |
273 | * first xattr that we find and walk forward | |
274 | */ | |
33345d01 | 275 | key.objectid = btrfs_ino(inode); |
962a298f | 276 | key.type = BTRFS_XATTR_ITEM_KEY; |
5103e947 JB |
277 | key.offset = 0; |
278 | ||
279 | path = btrfs_alloc_path(); | |
5103e947 JB |
280 | if (!path) |
281 | return -ENOMEM; | |
1caf9342 | 282 | path->reada = 2; |
5103e947 | 283 | |
5103e947 JB |
284 | /* search for our xattrs */ |
285 | ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); | |
286 | if (ret < 0) | |
287 | goto err; | |
2e6a0035 | 288 | |
5103e947 JB |
289 | while (1) { |
290 | leaf = path->nodes[0]; | |
5103e947 JB |
291 | slot = path->slots[0]; |
292 | ||
293 | /* this is where we start walking through the path */ | |
2e6a0035 | 294 | if (slot >= btrfs_header_nritems(leaf)) { |
5103e947 JB |
295 | /* |
296 | * if we've reached the last slot in this leaf we need | |
297 | * to go to the next leaf and reset everything | |
298 | */ | |
2e6a0035 LZ |
299 | ret = btrfs_next_leaf(root, path); |
300 | if (ret < 0) | |
301 | goto err; | |
302 | else if (ret > 0) | |
303 | break; | |
304 | continue; | |
5103e947 | 305 | } |
5103e947 | 306 | |
5103e947 JB |
307 | btrfs_item_key_to_cpu(leaf, &found_key, slot); |
308 | ||
309 | /* check to make sure this item is what we want */ | |
310 | if (found_key.objectid != key.objectid) | |
311 | break; | |
962a298f | 312 | if (found_key.type != BTRFS_XATTR_ITEM_KEY) |
5103e947 JB |
313 | break; |
314 | ||
315 | di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item); | |
22a94d44 | 316 | if (verify_dir_item(root, leaf, di)) |
db2254bc | 317 | goto next; |
5103e947 | 318 | |
eaa47d86 CH |
319 | name_len = btrfs_dir_name_len(leaf, di); |
320 | total_size += name_len + 1; | |
5103e947 JB |
321 | |
322 | /* we are just looking for how big our buffer needs to be */ | |
323 | if (!size) | |
2e6a0035 | 324 | goto next; |
5103e947 | 325 | |
eaa47d86 | 326 | if (!buffer || (name_len + 1) > size_left) { |
5103e947 | 327 | ret = -ERANGE; |
b16281c3 | 328 | goto err; |
5103e947 JB |
329 | } |
330 | ||
eaa47d86 CH |
331 | name_ptr = (unsigned long)(di + 1); |
332 | read_extent_buffer(leaf, buffer, name_ptr, name_len); | |
333 | buffer[name_len] = '\0'; | |
334 | ||
335 | size_left -= name_len + 1; | |
336 | buffer += name_len + 1; | |
2e6a0035 LZ |
337 | next: |
338 | path->slots[0]++; | |
5103e947 JB |
339 | } |
340 | ret = total_size; | |
341 | ||
342 | err: | |
5103e947 JB |
343 | btrfs_free_path(path); |
344 | ||
345 | return ret; | |
346 | } | |
347 | ||
5103e947 | 348 | /* |
95819c05 CH |
349 | * List of handlers for synthetic system.* attributes. All real ondisk |
350 | * attributes are handled directly. | |
351 | */ | |
f01cbd3f | 352 | const struct xattr_handler *btrfs_xattr_handlers[] = { |
0eda294d | 353 | #ifdef CONFIG_BTRFS_FS_POSIX_ACL |
996a710d CH |
354 | &posix_acl_access_xattr_handler, |
355 | &posix_acl_default_xattr_handler, | |
95819c05 CH |
356 | #endif |
357 | NULL, | |
358 | }; | |
359 | ||
360 | /* | |
361 | * Check if the attribute is in a supported namespace. | |
362 | * | |
363 | * This applied after the check for the synthetic attributes in the system | |
364 | * namespace. | |
5103e947 | 365 | */ |
95819c05 CH |
366 | static bool btrfs_is_valid_xattr(const char *name) |
367 | { | |
d397712b CM |
368 | return !strncmp(name, XATTR_SECURITY_PREFIX, |
369 | XATTR_SECURITY_PREFIX_LEN) || | |
95819c05 CH |
370 | !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) || |
371 | !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) || | |
63541927 FDBM |
372 | !strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN) || |
373 | !strncmp(name, XATTR_BTRFS_PREFIX, XATTR_BTRFS_PREFIX_LEN); | |
69a32ac5 CM |
374 | } |
375 | ||
95819c05 CH |
376 | ssize_t btrfs_getxattr(struct dentry *dentry, const char *name, |
377 | void *buffer, size_t size) | |
378 | { | |
379 | /* | |
380 | * If this is a request for a synthetic attribute in the system.* | |
381 | * namespace use the generic infrastructure to resolve a handler | |
382 | * for it via sb->s_xattr. | |
383 | */ | |
384 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
385 | return generic_getxattr(dentry, name, buffer, size); | |
5103e947 | 386 | |
95819c05 CH |
387 | if (!btrfs_is_valid_xattr(name)) |
388 | return -EOPNOTSUPP; | |
389 | return __btrfs_getxattr(dentry->d_inode, name, buffer, size); | |
390 | } | |
5103e947 | 391 | |
95819c05 CH |
392 | int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value, |
393 | size_t size, int flags) | |
394 | { | |
b83cc969 LZ |
395 | struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root; |
396 | ||
397 | /* | |
398 | * The permission on security.* and system.* is not checked | |
399 | * in permission(). | |
400 | */ | |
401 | if (btrfs_root_readonly(root)) | |
402 | return -EROFS; | |
403 | ||
95819c05 CH |
404 | /* |
405 | * If this is a request for a synthetic attribute in the system.* | |
406 | * namespace use the generic infrastructure to resolve a handler | |
407 | * for it via sb->s_xattr. | |
408 | */ | |
409 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
410 | return generic_setxattr(dentry, name, value, size, flags); | |
5103e947 | 411 | |
95819c05 CH |
412 | if (!btrfs_is_valid_xattr(name)) |
413 | return -EOPNOTSUPP; | |
5103e947 | 414 | |
63541927 FDBM |
415 | if (!strncmp(name, XATTR_BTRFS_PREFIX, XATTR_BTRFS_PREFIX_LEN)) |
416 | return btrfs_set_prop(dentry->d_inode, name, | |
417 | value, size, flags); | |
418 | ||
95819c05 CH |
419 | if (size == 0) |
420 | value = ""; /* empty EA, do not remove */ | |
f34f57a3 YZ |
421 | |
422 | return __btrfs_setxattr(NULL, dentry->d_inode, name, value, size, | |
423 | flags); | |
95819c05 CH |
424 | } |
425 | ||
426 | int btrfs_removexattr(struct dentry *dentry, const char *name) | |
427 | { | |
b83cc969 LZ |
428 | struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root; |
429 | ||
430 | /* | |
431 | * The permission on security.* and system.* is not checked | |
432 | * in permission(). | |
433 | */ | |
434 | if (btrfs_root_readonly(root)) | |
435 | return -EROFS; | |
436 | ||
95819c05 CH |
437 | /* |
438 | * If this is a request for a synthetic attribute in the system.* | |
439 | * namespace use the generic infrastructure to resolve a handler | |
440 | * for it via sb->s_xattr. | |
441 | */ | |
442 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
443 | return generic_removexattr(dentry, name); | |
444 | ||
445 | if (!btrfs_is_valid_xattr(name)) | |
446 | return -EOPNOTSUPP; | |
f34f57a3 | 447 | |
63541927 FDBM |
448 | if (!strncmp(name, XATTR_BTRFS_PREFIX, XATTR_BTRFS_PREFIX_LEN)) |
449 | return btrfs_set_prop(dentry->d_inode, name, | |
450 | NULL, 0, XATTR_REPLACE); | |
451 | ||
f34f57a3 YZ |
452 | return __btrfs_setxattr(NULL, dentry->d_inode, name, NULL, 0, |
453 | XATTR_REPLACE); | |
95819c05 | 454 | } |
0279b4cd | 455 | |
48a3b636 ES |
456 | static int btrfs_initxattrs(struct inode *inode, |
457 | const struct xattr *xattr_array, void *fs_info) | |
0279b4cd | 458 | { |
9d8f13ba MZ |
459 | const struct xattr *xattr; |
460 | struct btrfs_trans_handle *trans = fs_info; | |
0279b4cd | 461 | char *name; |
9d8f13ba | 462 | int err = 0; |
0279b4cd | 463 | |
9d8f13ba MZ |
464 | for (xattr = xattr_array; xattr->name != NULL; xattr++) { |
465 | name = kmalloc(XATTR_SECURITY_PREFIX_LEN + | |
466 | strlen(xattr->name) + 1, GFP_NOFS); | |
467 | if (!name) { | |
468 | err = -ENOMEM; | |
469 | break; | |
470 | } | |
0279b4cd | 471 | strcpy(name, XATTR_SECURITY_PREFIX); |
9d8f13ba MZ |
472 | strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name); |
473 | err = __btrfs_setxattr(trans, inode, name, | |
474 | xattr->value, xattr->value_len, 0); | |
0279b4cd | 475 | kfree(name); |
9d8f13ba MZ |
476 | if (err < 0) |
477 | break; | |
0279b4cd | 478 | } |
0279b4cd JO |
479 | return err; |
480 | } | |
9d8f13ba MZ |
481 | |
482 | int btrfs_xattr_security_init(struct btrfs_trans_handle *trans, | |
483 | struct inode *inode, struct inode *dir, | |
484 | const struct qstr *qstr) | |
485 | { | |
486 | return security_inode_init_security(inode, dir, qstr, | |
487 | &btrfs_initxattrs, trans); | |
488 | } |