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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> |
5103e947 JB |
25 | #include "ctree.h" |
26 | #include "btrfs_inode.h" | |
27 | #include "transaction.h" | |
28 | #include "xattr.h" | |
29 | #include "disk-io.h" | |
33268eaf | 30 | |
5103e947 | 31 | |
95819c05 CH |
32 | ssize_t __btrfs_getxattr(struct inode *inode, const char *name, |
33 | void *buffer, size_t size) | |
5103e947 JB |
34 | { |
35 | struct btrfs_dir_item *di; | |
36 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
37 | struct btrfs_path *path; | |
38 | struct extent_buffer *leaf; | |
5103e947 JB |
39 | int ret = 0; |
40 | unsigned long data_ptr; | |
5103e947 JB |
41 | |
42 | path = btrfs_alloc_path(); | |
95819c05 | 43 | if (!path) |
5103e947 | 44 | return -ENOMEM; |
5103e947 | 45 | |
5103e947 | 46 | /* lookup the xattr by name */ |
33345d01 | 47 | di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(inode), name, |
5103e947 | 48 | strlen(name), 0); |
07060404 | 49 | if (!di) { |
5103e947 JB |
50 | ret = -ENODATA; |
51 | goto out; | |
07060404 JB |
52 | } else if (IS_ERR(di)) { |
53 | ret = PTR_ERR(di); | |
54 | goto out; | |
5103e947 JB |
55 | } |
56 | ||
57 | leaf = path->nodes[0]; | |
58 | /* if size is 0, that means we want the size of the attr */ | |
59 | if (!size) { | |
60 | ret = btrfs_dir_data_len(leaf, di); | |
61 | goto out; | |
62 | } | |
63 | ||
64 | /* now get the data out of our dir_item */ | |
65 | if (btrfs_dir_data_len(leaf, di) > size) { | |
66 | ret = -ERANGE; | |
67 | goto out; | |
68 | } | |
07060404 JB |
69 | |
70 | /* | |
71 | * The way things are packed into the leaf is like this | |
72 | * |struct btrfs_dir_item|name|data| | |
73 | * where name is the xattr name, so security.foo, and data is the | |
74 | * content of the xattr. data_ptr points to the location in memory | |
75 | * where the data starts in the in memory leaf | |
76 | */ | |
5103e947 JB |
77 | data_ptr = (unsigned long)((char *)(di + 1) + |
78 | btrfs_dir_name_len(leaf, di)); | |
79 | read_extent_buffer(leaf, buffer, data_ptr, | |
3acd7ee8 | 80 | btrfs_dir_data_len(leaf, di)); |
5103e947 JB |
81 | ret = btrfs_dir_data_len(leaf, di); |
82 | ||
83 | out: | |
5103e947 JB |
84 | btrfs_free_path(path); |
85 | return ret; | |
86 | } | |
87 | ||
f34f57a3 YZ |
88 | static int do_setxattr(struct btrfs_trans_handle *trans, |
89 | struct inode *inode, const char *name, | |
90 | const void *value, size_t size, int flags) | |
5103e947 JB |
91 | { |
92 | struct btrfs_dir_item *di; | |
93 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
5103e947 | 94 | struct btrfs_path *path; |
f34f57a3 YZ |
95 | size_t name_len = strlen(name); |
96 | int ret = 0; | |
97 | ||
98 | if (name_len + size > BTRFS_MAX_XATTR_SIZE(root)) | |
99 | return -ENOSPC; | |
5103e947 JB |
100 | |
101 | path = btrfs_alloc_path(); | |
95819c05 | 102 | if (!path) |
5103e947 | 103 | return -ENOMEM; |
5103e947 | 104 | |
fa09200b JB |
105 | if (flags & XATTR_REPLACE) { |
106 | di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(inode), name, | |
107 | name_len, -1); | |
108 | if (IS_ERR(di)) { | |
109 | ret = PTR_ERR(di); | |
110 | goto out; | |
111 | } else if (!di) { | |
112 | ret = -ENODATA; | |
5103e947 JB |
113 | goto out; |
114 | } | |
5103e947 | 115 | ret = btrfs_delete_one_dir_name(trans, root, path, di); |
fa09200b JB |
116 | if (ret) |
117 | goto out; | |
b3b4aa74 | 118 | btrfs_release_path(path); |
4815053a DS |
119 | |
120 | /* | |
121 | * remove the attribute | |
122 | */ | |
123 | if (!value) | |
124 | goto out; | |
fa09200b | 125 | } |
5103e947 | 126 | |
fa09200b JB |
127 | again: |
128 | ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(inode), | |
129 | name, name_len, value, size); | |
ed3ee9f4 JB |
130 | /* |
131 | * If we're setting an xattr to a new value but the new value is say | |
132 | * exactly BTRFS_MAX_XATTR_SIZE, we could end up with EOVERFLOW getting | |
133 | * back from split_leaf. This is because it thinks we'll be extending | |
134 | * the existing item size, but we're asking for enough space to add the | |
135 | * item itself. So if we get EOVERFLOW just set ret to EEXIST and let | |
136 | * the rest of the function figure it out. | |
137 | */ | |
138 | if (ret == -EOVERFLOW) | |
139 | ret = -EEXIST; | |
140 | ||
fa09200b JB |
141 | if (ret == -EEXIST) { |
142 | if (flags & XATTR_CREATE) | |
5103e947 | 143 | goto out; |
fa09200b JB |
144 | /* |
145 | * We can't use the path we already have since we won't have the | |
146 | * proper locking for a delete, so release the path and | |
147 | * re-lookup to delete the thing. | |
148 | */ | |
b3b4aa74 | 149 | btrfs_release_path(path); |
fa09200b JB |
150 | di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(inode), |
151 | name, name_len, -1); | |
152 | if (IS_ERR(di)) { | |
153 | ret = PTR_ERR(di); | |
154 | goto out; | |
155 | } else if (!di) { | |
156 | /* Shouldn't happen but just in case... */ | |
157 | btrfs_release_path(path); | |
158 | goto again; | |
159 | } | |
33268eaf | 160 | |
fa09200b JB |
161 | ret = btrfs_delete_one_dir_name(trans, root, path, di); |
162 | if (ret) | |
33268eaf | 163 | goto out; |
fa09200b JB |
164 | |
165 | /* | |
166 | * We have a value to set, so go back and try to insert it now. | |
167 | */ | |
168 | if (value) { | |
169 | btrfs_release_path(path); | |
170 | goto again; | |
33268eaf | 171 | } |
5103e947 | 172 | } |
f34f57a3 YZ |
173 | out: |
174 | btrfs_free_path(path); | |
175 | return ret; | |
176 | } | |
177 | ||
4815053a DS |
178 | /* |
179 | * @value: "" makes the attribute to empty, NULL removes it | |
180 | */ | |
f34f57a3 YZ |
181 | int __btrfs_setxattr(struct btrfs_trans_handle *trans, |
182 | struct inode *inode, const char *name, | |
183 | const void *value, size_t size, int flags) | |
184 | { | |
185 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
186 | int ret; | |
187 | ||
188 | if (trans) | |
189 | return do_setxattr(trans, inode, name, value, size, flags); | |
190 | ||
a22285a6 YZ |
191 | trans = btrfs_start_transaction(root, 2); |
192 | if (IS_ERR(trans)) | |
193 | return PTR_ERR(trans); | |
5103e947 | 194 | |
f34f57a3 YZ |
195 | ret = do_setxattr(trans, inode, name, value, size, flags); |
196 | if (ret) | |
197 | goto out; | |
198 | ||
0c4d2d95 | 199 | inode_inc_iversion(inode); |
f34f57a3 YZ |
200 | inode->i_ctime = CURRENT_TIME; |
201 | ret = btrfs_update_inode(trans, root, inode); | |
202 | BUG_ON(ret); | |
203 | out: | |
7ad85bb7 | 204 | btrfs_end_transaction(trans, root); |
5103e947 JB |
205 | return ret; |
206 | } | |
207 | ||
208 | ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size) | |
209 | { | |
210 | struct btrfs_key key, found_key; | |
211 | struct inode *inode = dentry->d_inode; | |
212 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
213 | struct btrfs_path *path; | |
5103e947 JB |
214 | struct extent_buffer *leaf; |
215 | struct btrfs_dir_item *di; | |
2e6a0035 | 216 | int ret = 0, slot; |
eaa47d86 | 217 | size_t total_size = 0, size_left = size; |
5103e947 | 218 | unsigned long name_ptr; |
eaa47d86 | 219 | size_t name_len; |
5103e947 JB |
220 | |
221 | /* | |
222 | * ok we want all objects associated with this id. | |
223 | * NOTE: we set key.offset = 0; because we want to start with the | |
224 | * first xattr that we find and walk forward | |
225 | */ | |
33345d01 | 226 | key.objectid = btrfs_ino(inode); |
5103e947 JB |
227 | btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY); |
228 | key.offset = 0; | |
229 | ||
230 | path = btrfs_alloc_path(); | |
5103e947 JB |
231 | if (!path) |
232 | return -ENOMEM; | |
1caf9342 | 233 | path->reada = 2; |
5103e947 | 234 | |
5103e947 JB |
235 | /* search for our xattrs */ |
236 | ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); | |
237 | if (ret < 0) | |
238 | goto err; | |
2e6a0035 | 239 | |
5103e947 JB |
240 | while (1) { |
241 | leaf = path->nodes[0]; | |
5103e947 JB |
242 | slot = path->slots[0]; |
243 | ||
244 | /* this is where we start walking through the path */ | |
2e6a0035 | 245 | if (slot >= btrfs_header_nritems(leaf)) { |
5103e947 JB |
246 | /* |
247 | * if we've reached the last slot in this leaf we need | |
248 | * to go to the next leaf and reset everything | |
249 | */ | |
2e6a0035 LZ |
250 | ret = btrfs_next_leaf(root, path); |
251 | if (ret < 0) | |
252 | goto err; | |
253 | else if (ret > 0) | |
254 | break; | |
255 | continue; | |
5103e947 | 256 | } |
5103e947 | 257 | |
5103e947 JB |
258 | btrfs_item_key_to_cpu(leaf, &found_key, slot); |
259 | ||
260 | /* check to make sure this item is what we want */ | |
261 | if (found_key.objectid != key.objectid) | |
262 | break; | |
263 | if (btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY) | |
264 | break; | |
265 | ||
266 | di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item); | |
22a94d44 JB |
267 | if (verify_dir_item(root, leaf, di)) |
268 | continue; | |
5103e947 | 269 | |
eaa47d86 CH |
270 | name_len = btrfs_dir_name_len(leaf, di); |
271 | total_size += name_len + 1; | |
5103e947 JB |
272 | |
273 | /* we are just looking for how big our buffer needs to be */ | |
274 | if (!size) | |
2e6a0035 | 275 | goto next; |
5103e947 | 276 | |
eaa47d86 | 277 | if (!buffer || (name_len + 1) > size_left) { |
5103e947 | 278 | ret = -ERANGE; |
b16281c3 | 279 | goto err; |
5103e947 JB |
280 | } |
281 | ||
eaa47d86 CH |
282 | name_ptr = (unsigned long)(di + 1); |
283 | read_extent_buffer(leaf, buffer, name_ptr, name_len); | |
284 | buffer[name_len] = '\0'; | |
285 | ||
286 | size_left -= name_len + 1; | |
287 | buffer += name_len + 1; | |
2e6a0035 LZ |
288 | next: |
289 | path->slots[0]++; | |
5103e947 JB |
290 | } |
291 | ret = total_size; | |
292 | ||
293 | err: | |
5103e947 JB |
294 | btrfs_free_path(path); |
295 | ||
296 | return ret; | |
297 | } | |
298 | ||
5103e947 | 299 | /* |
95819c05 CH |
300 | * List of handlers for synthetic system.* attributes. All real ondisk |
301 | * attributes are handled directly. | |
302 | */ | |
f01cbd3f | 303 | const struct xattr_handler *btrfs_xattr_handlers[] = { |
0eda294d | 304 | #ifdef CONFIG_BTRFS_FS_POSIX_ACL |
95819c05 CH |
305 | &btrfs_xattr_acl_access_handler, |
306 | &btrfs_xattr_acl_default_handler, | |
307 | #endif | |
308 | NULL, | |
309 | }; | |
310 | ||
311 | /* | |
312 | * Check if the attribute is in a supported namespace. | |
313 | * | |
314 | * This applied after the check for the synthetic attributes in the system | |
315 | * namespace. | |
5103e947 | 316 | */ |
95819c05 CH |
317 | static bool btrfs_is_valid_xattr(const char *name) |
318 | { | |
d397712b CM |
319 | return !strncmp(name, XATTR_SECURITY_PREFIX, |
320 | XATTR_SECURITY_PREFIX_LEN) || | |
95819c05 CH |
321 | !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) || |
322 | !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) || | |
323 | !strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN); | |
69a32ac5 CM |
324 | } |
325 | ||
95819c05 CH |
326 | ssize_t btrfs_getxattr(struct dentry *dentry, const char *name, |
327 | void *buffer, size_t size) | |
328 | { | |
329 | /* | |
330 | * If this is a request for a synthetic attribute in the system.* | |
331 | * namespace use the generic infrastructure to resolve a handler | |
332 | * for it via sb->s_xattr. | |
333 | */ | |
334 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
335 | return generic_getxattr(dentry, name, buffer, size); | |
5103e947 | 336 | |
95819c05 CH |
337 | if (!btrfs_is_valid_xattr(name)) |
338 | return -EOPNOTSUPP; | |
339 | return __btrfs_getxattr(dentry->d_inode, name, buffer, size); | |
340 | } | |
5103e947 | 341 | |
95819c05 CH |
342 | int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value, |
343 | size_t size, int flags) | |
344 | { | |
b83cc969 LZ |
345 | struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root; |
346 | ||
347 | /* | |
348 | * The permission on security.* and system.* is not checked | |
349 | * in permission(). | |
350 | */ | |
351 | if (btrfs_root_readonly(root)) | |
352 | return -EROFS; | |
353 | ||
95819c05 CH |
354 | /* |
355 | * If this is a request for a synthetic attribute in the system.* | |
356 | * namespace use the generic infrastructure to resolve a handler | |
357 | * for it via sb->s_xattr. | |
358 | */ | |
359 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
360 | return generic_setxattr(dentry, name, value, size, flags); | |
5103e947 | 361 | |
95819c05 CH |
362 | if (!btrfs_is_valid_xattr(name)) |
363 | return -EOPNOTSUPP; | |
5103e947 | 364 | |
95819c05 CH |
365 | if (size == 0) |
366 | value = ""; /* empty EA, do not remove */ | |
f34f57a3 YZ |
367 | |
368 | return __btrfs_setxattr(NULL, dentry->d_inode, name, value, size, | |
369 | flags); | |
95819c05 CH |
370 | } |
371 | ||
372 | int btrfs_removexattr(struct dentry *dentry, const char *name) | |
373 | { | |
b83cc969 LZ |
374 | struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root; |
375 | ||
376 | /* | |
377 | * The permission on security.* and system.* is not checked | |
378 | * in permission(). | |
379 | */ | |
380 | if (btrfs_root_readonly(root)) | |
381 | return -EROFS; | |
382 | ||
95819c05 CH |
383 | /* |
384 | * If this is a request for a synthetic attribute in the system.* | |
385 | * namespace use the generic infrastructure to resolve a handler | |
386 | * for it via sb->s_xattr. | |
387 | */ | |
388 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
389 | return generic_removexattr(dentry, name); | |
390 | ||
391 | if (!btrfs_is_valid_xattr(name)) | |
392 | return -EOPNOTSUPP; | |
f34f57a3 YZ |
393 | |
394 | return __btrfs_setxattr(NULL, dentry->d_inode, name, NULL, 0, | |
395 | XATTR_REPLACE); | |
95819c05 | 396 | } |
0279b4cd | 397 | |
9d8f13ba MZ |
398 | int btrfs_initxattrs(struct inode *inode, const struct xattr *xattr_array, |
399 | void *fs_info) | |
0279b4cd | 400 | { |
9d8f13ba MZ |
401 | const struct xattr *xattr; |
402 | struct btrfs_trans_handle *trans = fs_info; | |
0279b4cd | 403 | char *name; |
9d8f13ba | 404 | int err = 0; |
0279b4cd | 405 | |
9d8f13ba MZ |
406 | for (xattr = xattr_array; xattr->name != NULL; xattr++) { |
407 | name = kmalloc(XATTR_SECURITY_PREFIX_LEN + | |
408 | strlen(xattr->name) + 1, GFP_NOFS); | |
409 | if (!name) { | |
410 | err = -ENOMEM; | |
411 | break; | |
412 | } | |
0279b4cd | 413 | strcpy(name, XATTR_SECURITY_PREFIX); |
9d8f13ba MZ |
414 | strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name); |
415 | err = __btrfs_setxattr(trans, inode, name, | |
416 | xattr->value, xattr->value_len, 0); | |
0279b4cd | 417 | kfree(name); |
9d8f13ba MZ |
418 | if (err < 0) |
419 | break; | |
0279b4cd | 420 | } |
0279b4cd JO |
421 | return err; |
422 | } | |
9d8f13ba MZ |
423 | |
424 | int btrfs_xattr_security_init(struct btrfs_trans_handle *trans, | |
425 | struct inode *inode, struct inode *dir, | |
426 | const struct qstr *qstr) | |
427 | { | |
428 | return security_inode_init_security(inode, dir, qstr, | |
429 | &btrfs_initxattrs, trans); | |
430 | } |