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" |
33268eaf | 32 | |
5103e947 | 33 | |
95819c05 CH |
34 | ssize_t __btrfs_getxattr(struct inode *inode, const char *name, |
35 | void *buffer, size_t size) | |
5103e947 JB |
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; | |
5103e947 JB |
41 | int ret = 0; |
42 | unsigned long data_ptr; | |
5103e947 JB |
43 | |
44 | path = btrfs_alloc_path(); | |
95819c05 | 45 | if (!path) |
5103e947 | 46 | return -ENOMEM; |
5103e947 | 47 | |
5103e947 | 48 | /* lookup the xattr by name */ |
33345d01 | 49 | di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(inode), name, |
5103e947 | 50 | strlen(name), 0); |
07060404 | 51 | if (!di) { |
5103e947 JB |
52 | ret = -ENODATA; |
53 | goto out; | |
07060404 JB |
54 | } else if (IS_ERR(di)) { |
55 | ret = PTR_ERR(di); | |
56 | goto out; | |
5103e947 JB |
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 | } | |
07060404 JB |
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 | */ | |
5103e947 JB |
79 | data_ptr = (unsigned long)((char *)(di + 1) + |
80 | btrfs_dir_name_len(leaf, di)); | |
81 | read_extent_buffer(leaf, buffer, data_ptr, | |
3acd7ee8 | 82 | btrfs_dir_data_len(leaf, di)); |
5103e947 JB |
83 | ret = btrfs_dir_data_len(leaf, di); |
84 | ||
85 | out: | |
5103e947 JB |
86 | btrfs_free_path(path); |
87 | return ret; | |
88 | } | |
89 | ||
f34f57a3 YZ |
90 | static int do_setxattr(struct btrfs_trans_handle *trans, |
91 | struct inode *inode, const char *name, | |
92 | const void *value, size_t size, int flags) | |
5103e947 JB |
93 | { |
94 | struct btrfs_dir_item *di; | |
95 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
5103e947 | 96 | struct btrfs_path *path; |
f34f57a3 YZ |
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; | |
5103e947 JB |
102 | |
103 | path = btrfs_alloc_path(); | |
95819c05 | 104 | if (!path) |
5103e947 | 105 | return -ENOMEM; |
5103e947 | 106 | |
fa09200b JB |
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; | |
5103e947 JB |
115 | goto out; |
116 | } | |
5103e947 | 117 | ret = btrfs_delete_one_dir_name(trans, root, path, di); |
fa09200b JB |
118 | if (ret) |
119 | goto out; | |
b3b4aa74 | 120 | btrfs_release_path(path); |
4815053a DS |
121 | |
122 | /* | |
123 | * remove the attribute | |
124 | */ | |
125 | if (!value) | |
126 | goto out; | |
01e6deb2 LB |
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); | |
fa09200b | 137 | } |
5103e947 | 138 | |
fa09200b JB |
139 | again: |
140 | ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(inode), | |
141 | name, name_len, value, size); | |
ed3ee9f4 JB |
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 | ||
fa09200b JB |
153 | if (ret == -EEXIST) { |
154 | if (flags & XATTR_CREATE) | |
5103e947 | 155 | goto out; |
fa09200b JB |
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 | */ | |
b3b4aa74 | 161 | btrfs_release_path(path); |
fa09200b JB |
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 | } | |
33268eaf | 172 | |
fa09200b JB |
173 | ret = btrfs_delete_one_dir_name(trans, root, path, di); |
174 | if (ret) | |
33268eaf | 175 | goto out; |
fa09200b JB |
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; | |
33268eaf | 183 | } |
5103e947 | 184 | } |
f34f57a3 YZ |
185 | out: |
186 | btrfs_free_path(path); | |
187 | return ret; | |
188 | } | |
189 | ||
4815053a DS |
190 | /* |
191 | * @value: "" makes the attribute to empty, NULL removes it | |
192 | */ | |
f34f57a3 YZ |
193 | int __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 | ||
a22285a6 YZ |
203 | trans = btrfs_start_transaction(root, 2); |
204 | if (IS_ERR(trans)) | |
205 | return PTR_ERR(trans); | |
5103e947 | 206 | |
f34f57a3 YZ |
207 | ret = do_setxattr(trans, inode, name, value, size, flags); |
208 | if (ret) | |
209 | goto out; | |
210 | ||
0c4d2d95 | 211 | inode_inc_iversion(inode); |
f34f57a3 | 212 | inode->i_ctime = CURRENT_TIME; |
e9976151 | 213 | set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags); |
f34f57a3 YZ |
214 | ret = btrfs_update_inode(trans, root, inode); |
215 | BUG_ON(ret); | |
216 | out: | |
7ad85bb7 | 217 | btrfs_end_transaction(trans, root); |
5103e947 JB |
218 | return ret; |
219 | } | |
220 | ||
221 | ssize_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; | |
5103e947 JB |
227 | struct extent_buffer *leaf; |
228 | struct btrfs_dir_item *di; | |
2e6a0035 | 229 | int ret = 0, slot; |
eaa47d86 | 230 | size_t total_size = 0, size_left = size; |
5103e947 | 231 | unsigned long name_ptr; |
eaa47d86 | 232 | size_t name_len; |
5103e947 JB |
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 | */ | |
33345d01 | 239 | key.objectid = btrfs_ino(inode); |
962a298f | 240 | key.type = BTRFS_XATTR_ITEM_KEY; |
5103e947 JB |
241 | key.offset = 0; |
242 | ||
243 | path = btrfs_alloc_path(); | |
5103e947 JB |
244 | if (!path) |
245 | return -ENOMEM; | |
1caf9342 | 246 | path->reada = 2; |
5103e947 | 247 | |
5103e947 JB |
248 | /* search for our xattrs */ |
249 | ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); | |
250 | if (ret < 0) | |
251 | goto err; | |
2e6a0035 | 252 | |
5103e947 JB |
253 | while (1) { |
254 | leaf = path->nodes[0]; | |
5103e947 JB |
255 | slot = path->slots[0]; |
256 | ||
257 | /* this is where we start walking through the path */ | |
2e6a0035 | 258 | if (slot >= btrfs_header_nritems(leaf)) { |
5103e947 JB |
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 | */ | |
2e6a0035 LZ |
263 | ret = btrfs_next_leaf(root, path); |
264 | if (ret < 0) | |
265 | goto err; | |
266 | else if (ret > 0) | |
267 | break; | |
268 | continue; | |
5103e947 | 269 | } |
5103e947 | 270 | |
5103e947 JB |
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; | |
962a298f | 276 | if (found_key.type != BTRFS_XATTR_ITEM_KEY) |
5103e947 JB |
277 | break; |
278 | ||
279 | di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item); | |
22a94d44 | 280 | if (verify_dir_item(root, leaf, di)) |
db2254bc | 281 | goto next; |
5103e947 | 282 | |
eaa47d86 CH |
283 | name_len = btrfs_dir_name_len(leaf, di); |
284 | total_size += name_len + 1; | |
5103e947 JB |
285 | |
286 | /* we are just looking for how big our buffer needs to be */ | |
287 | if (!size) | |
2e6a0035 | 288 | goto next; |
5103e947 | 289 | |
eaa47d86 | 290 | if (!buffer || (name_len + 1) > size_left) { |
5103e947 | 291 | ret = -ERANGE; |
b16281c3 | 292 | goto err; |
5103e947 JB |
293 | } |
294 | ||
eaa47d86 CH |
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; | |
2e6a0035 LZ |
301 | next: |
302 | path->slots[0]++; | |
5103e947 JB |
303 | } |
304 | ret = total_size; | |
305 | ||
306 | err: | |
5103e947 JB |
307 | btrfs_free_path(path); |
308 | ||
309 | return ret; | |
310 | } | |
311 | ||
5103e947 | 312 | /* |
95819c05 CH |
313 | * List of handlers for synthetic system.* attributes. All real ondisk |
314 | * attributes are handled directly. | |
315 | */ | |
f01cbd3f | 316 | const struct xattr_handler *btrfs_xattr_handlers[] = { |
0eda294d | 317 | #ifdef CONFIG_BTRFS_FS_POSIX_ACL |
996a710d CH |
318 | &posix_acl_access_xattr_handler, |
319 | &posix_acl_default_xattr_handler, | |
95819c05 CH |
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. | |
5103e947 | 329 | */ |
95819c05 CH |
330 | static bool btrfs_is_valid_xattr(const char *name) |
331 | { | |
d397712b CM |
332 | return !strncmp(name, XATTR_SECURITY_PREFIX, |
333 | XATTR_SECURITY_PREFIX_LEN) || | |
95819c05 CH |
334 | !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) || |
335 | !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) || | |
63541927 FDBM |
336 | !strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN) || |
337 | !strncmp(name, XATTR_BTRFS_PREFIX, XATTR_BTRFS_PREFIX_LEN); | |
69a32ac5 CM |
338 | } |
339 | ||
95819c05 CH |
340 | ssize_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); | |
5103e947 | 350 | |
95819c05 CH |
351 | if (!btrfs_is_valid_xattr(name)) |
352 | return -EOPNOTSUPP; | |
353 | return __btrfs_getxattr(dentry->d_inode, name, buffer, size); | |
354 | } | |
5103e947 | 355 | |
95819c05 CH |
356 | int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value, |
357 | size_t size, int flags) | |
358 | { | |
b83cc969 LZ |
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 | ||
95819c05 CH |
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); | |
5103e947 | 375 | |
95819c05 CH |
376 | if (!btrfs_is_valid_xattr(name)) |
377 | return -EOPNOTSUPP; | |
5103e947 | 378 | |
63541927 FDBM |
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 | ||
95819c05 CH |
383 | if (size == 0) |
384 | value = ""; /* empty EA, do not remove */ | |
f34f57a3 YZ |
385 | |
386 | return __btrfs_setxattr(NULL, dentry->d_inode, name, value, size, | |
387 | flags); | |
95819c05 CH |
388 | } |
389 | ||
390 | int btrfs_removexattr(struct dentry *dentry, const char *name) | |
391 | { | |
b83cc969 LZ |
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 | ||
95819c05 CH |
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; | |
f34f57a3 | 411 | |
63541927 FDBM |
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 | ||
f34f57a3 YZ |
416 | return __btrfs_setxattr(NULL, dentry->d_inode, name, NULL, 0, |
417 | XATTR_REPLACE); | |
95819c05 | 418 | } |
0279b4cd | 419 | |
48a3b636 ES |
420 | static int btrfs_initxattrs(struct inode *inode, |
421 | const struct xattr *xattr_array, void *fs_info) | |
0279b4cd | 422 | { |
9d8f13ba MZ |
423 | const struct xattr *xattr; |
424 | struct btrfs_trans_handle *trans = fs_info; | |
0279b4cd | 425 | char *name; |
9d8f13ba | 426 | int err = 0; |
0279b4cd | 427 | |
9d8f13ba MZ |
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 | } | |
0279b4cd | 435 | strcpy(name, XATTR_SECURITY_PREFIX); |
9d8f13ba MZ |
436 | strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name); |
437 | err = __btrfs_setxattr(trans, inode, name, | |
438 | xattr->value, xattr->value_len, 0); | |
0279b4cd | 439 | kfree(name); |
9d8f13ba MZ |
440 | if (err < 0) |
441 | break; | |
0279b4cd | 442 | } |
0279b4cd JO |
443 | return err; |
444 | } | |
9d8f13ba MZ |
445 | |
446 | int 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 | } |