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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); |
fa09200b | 119 | } |
5103e947 | 120 | |
fa09200b JB |
121 | again: |
122 | ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(inode), | |
123 | name, name_len, value, size); | |
124 | if (ret == -EEXIST) { | |
125 | if (flags & XATTR_CREATE) | |
5103e947 | 126 | goto out; |
fa09200b JB |
127 | /* |
128 | * We can't use the path we already have since we won't have the | |
129 | * proper locking for a delete, so release the path and | |
130 | * re-lookup to delete the thing. | |
131 | */ | |
b3b4aa74 | 132 | btrfs_release_path(path); |
fa09200b JB |
133 | di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(inode), |
134 | name, name_len, -1); | |
135 | if (IS_ERR(di)) { | |
136 | ret = PTR_ERR(di); | |
137 | goto out; | |
138 | } else if (!di) { | |
139 | /* Shouldn't happen but just in case... */ | |
140 | btrfs_release_path(path); | |
141 | goto again; | |
142 | } | |
33268eaf | 143 | |
fa09200b JB |
144 | ret = btrfs_delete_one_dir_name(trans, root, path, di); |
145 | if (ret) | |
33268eaf | 146 | goto out; |
fa09200b JB |
147 | |
148 | /* | |
149 | * We have a value to set, so go back and try to insert it now. | |
150 | */ | |
151 | if (value) { | |
152 | btrfs_release_path(path); | |
153 | goto again; | |
33268eaf | 154 | } |
5103e947 | 155 | } |
f34f57a3 YZ |
156 | out: |
157 | btrfs_free_path(path); | |
158 | return ret; | |
159 | } | |
160 | ||
161 | int __btrfs_setxattr(struct btrfs_trans_handle *trans, | |
162 | struct inode *inode, const char *name, | |
163 | const void *value, size_t size, int flags) | |
164 | { | |
165 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
166 | int ret; | |
167 | ||
168 | if (trans) | |
169 | return do_setxattr(trans, inode, name, value, size, flags); | |
170 | ||
a22285a6 YZ |
171 | trans = btrfs_start_transaction(root, 2); |
172 | if (IS_ERR(trans)) | |
173 | return PTR_ERR(trans); | |
5103e947 | 174 | |
f34f57a3 YZ |
175 | ret = do_setxattr(trans, inode, name, value, size, flags); |
176 | if (ret) | |
177 | goto out; | |
178 | ||
179 | inode->i_ctime = CURRENT_TIME; | |
180 | ret = btrfs_update_inode(trans, root, inode); | |
181 | BUG_ON(ret); | |
182 | out: | |
183 | btrfs_end_transaction_throttle(trans, root); | |
5103e947 JB |
184 | return ret; |
185 | } | |
186 | ||
187 | ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size) | |
188 | { | |
189 | struct btrfs_key key, found_key; | |
190 | struct inode *inode = dentry->d_inode; | |
191 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
192 | struct btrfs_path *path; | |
5103e947 JB |
193 | struct extent_buffer *leaf; |
194 | struct btrfs_dir_item *di; | |
2e6a0035 | 195 | int ret = 0, slot; |
eaa47d86 | 196 | size_t total_size = 0, size_left = size; |
5103e947 | 197 | unsigned long name_ptr; |
eaa47d86 | 198 | size_t name_len; |
5103e947 JB |
199 | |
200 | /* | |
201 | * ok we want all objects associated with this id. | |
202 | * NOTE: we set key.offset = 0; because we want to start with the | |
203 | * first xattr that we find and walk forward | |
204 | */ | |
33345d01 | 205 | key.objectid = btrfs_ino(inode); |
5103e947 JB |
206 | btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY); |
207 | key.offset = 0; | |
208 | ||
209 | path = btrfs_alloc_path(); | |
5103e947 JB |
210 | if (!path) |
211 | return -ENOMEM; | |
1caf9342 | 212 | path->reada = 2; |
5103e947 | 213 | |
5103e947 JB |
214 | /* search for our xattrs */ |
215 | ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); | |
216 | if (ret < 0) | |
217 | goto err; | |
2e6a0035 | 218 | |
5103e947 JB |
219 | while (1) { |
220 | leaf = path->nodes[0]; | |
5103e947 JB |
221 | slot = path->slots[0]; |
222 | ||
223 | /* this is where we start walking through the path */ | |
2e6a0035 | 224 | if (slot >= btrfs_header_nritems(leaf)) { |
5103e947 JB |
225 | /* |
226 | * if we've reached the last slot in this leaf we need | |
227 | * to go to the next leaf and reset everything | |
228 | */ | |
2e6a0035 LZ |
229 | ret = btrfs_next_leaf(root, path); |
230 | if (ret < 0) | |
231 | goto err; | |
232 | else if (ret > 0) | |
233 | break; | |
234 | continue; | |
5103e947 | 235 | } |
5103e947 | 236 | |
5103e947 JB |
237 | btrfs_item_key_to_cpu(leaf, &found_key, slot); |
238 | ||
239 | /* check to make sure this item is what we want */ | |
240 | if (found_key.objectid != key.objectid) | |
241 | break; | |
242 | if (btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY) | |
243 | break; | |
244 | ||
245 | di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item); | |
22a94d44 JB |
246 | if (verify_dir_item(root, leaf, di)) |
247 | continue; | |
5103e947 | 248 | |
eaa47d86 CH |
249 | name_len = btrfs_dir_name_len(leaf, di); |
250 | total_size += name_len + 1; | |
5103e947 JB |
251 | |
252 | /* we are just looking for how big our buffer needs to be */ | |
253 | if (!size) | |
2e6a0035 | 254 | goto next; |
5103e947 | 255 | |
eaa47d86 | 256 | if (!buffer || (name_len + 1) > size_left) { |
5103e947 | 257 | ret = -ERANGE; |
b16281c3 | 258 | goto err; |
5103e947 JB |
259 | } |
260 | ||
eaa47d86 CH |
261 | name_ptr = (unsigned long)(di + 1); |
262 | read_extent_buffer(leaf, buffer, name_ptr, name_len); | |
263 | buffer[name_len] = '\0'; | |
264 | ||
265 | size_left -= name_len + 1; | |
266 | buffer += name_len + 1; | |
2e6a0035 LZ |
267 | next: |
268 | path->slots[0]++; | |
5103e947 JB |
269 | } |
270 | ret = total_size; | |
271 | ||
272 | err: | |
5103e947 JB |
273 | btrfs_free_path(path); |
274 | ||
275 | return ret; | |
276 | } | |
277 | ||
5103e947 | 278 | /* |
95819c05 CH |
279 | * List of handlers for synthetic system.* attributes. All real ondisk |
280 | * attributes are handled directly. | |
281 | */ | |
f01cbd3f | 282 | const struct xattr_handler *btrfs_xattr_handlers[] = { |
0eda294d | 283 | #ifdef CONFIG_BTRFS_FS_POSIX_ACL |
95819c05 CH |
284 | &btrfs_xattr_acl_access_handler, |
285 | &btrfs_xattr_acl_default_handler, | |
286 | #endif | |
287 | NULL, | |
288 | }; | |
289 | ||
290 | /* | |
291 | * Check if the attribute is in a supported namespace. | |
292 | * | |
293 | * This applied after the check for the synthetic attributes in the system | |
294 | * namespace. | |
5103e947 | 295 | */ |
95819c05 CH |
296 | static bool btrfs_is_valid_xattr(const char *name) |
297 | { | |
d397712b CM |
298 | return !strncmp(name, XATTR_SECURITY_PREFIX, |
299 | XATTR_SECURITY_PREFIX_LEN) || | |
95819c05 CH |
300 | !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) || |
301 | !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) || | |
302 | !strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN); | |
69a32ac5 CM |
303 | } |
304 | ||
95819c05 CH |
305 | ssize_t btrfs_getxattr(struct dentry *dentry, const char *name, |
306 | void *buffer, size_t size) | |
307 | { | |
308 | /* | |
309 | * If this is a request for a synthetic attribute in the system.* | |
310 | * namespace use the generic infrastructure to resolve a handler | |
311 | * for it via sb->s_xattr. | |
312 | */ | |
313 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
314 | return generic_getxattr(dentry, name, buffer, size); | |
5103e947 | 315 | |
95819c05 CH |
316 | if (!btrfs_is_valid_xattr(name)) |
317 | return -EOPNOTSUPP; | |
318 | return __btrfs_getxattr(dentry->d_inode, name, buffer, size); | |
319 | } | |
5103e947 | 320 | |
95819c05 CH |
321 | int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value, |
322 | size_t size, int flags) | |
323 | { | |
b83cc969 LZ |
324 | struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root; |
325 | ||
326 | /* | |
327 | * The permission on security.* and system.* is not checked | |
328 | * in permission(). | |
329 | */ | |
330 | if (btrfs_root_readonly(root)) | |
331 | return -EROFS; | |
332 | ||
95819c05 CH |
333 | /* |
334 | * If this is a request for a synthetic attribute in the system.* | |
335 | * namespace use the generic infrastructure to resolve a handler | |
336 | * for it via sb->s_xattr. | |
337 | */ | |
338 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
339 | return generic_setxattr(dentry, name, value, size, flags); | |
5103e947 | 340 | |
95819c05 CH |
341 | if (!btrfs_is_valid_xattr(name)) |
342 | return -EOPNOTSUPP; | |
5103e947 | 343 | |
95819c05 CH |
344 | if (size == 0) |
345 | value = ""; /* empty EA, do not remove */ | |
f34f57a3 YZ |
346 | |
347 | return __btrfs_setxattr(NULL, dentry->d_inode, name, value, size, | |
348 | flags); | |
95819c05 CH |
349 | } |
350 | ||
351 | int btrfs_removexattr(struct dentry *dentry, const char *name) | |
352 | { | |
b83cc969 LZ |
353 | struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root; |
354 | ||
355 | /* | |
356 | * The permission on security.* and system.* is not checked | |
357 | * in permission(). | |
358 | */ | |
359 | if (btrfs_root_readonly(root)) | |
360 | return -EROFS; | |
361 | ||
95819c05 CH |
362 | /* |
363 | * If this is a request for a synthetic attribute in the system.* | |
364 | * namespace use the generic infrastructure to resolve a handler | |
365 | * for it via sb->s_xattr. | |
366 | */ | |
367 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
368 | return generic_removexattr(dentry, name); | |
369 | ||
370 | if (!btrfs_is_valid_xattr(name)) | |
371 | return -EOPNOTSUPP; | |
f34f57a3 YZ |
372 | |
373 | return __btrfs_setxattr(NULL, dentry->d_inode, name, NULL, 0, | |
374 | XATTR_REPLACE); | |
95819c05 | 375 | } |
0279b4cd | 376 | |
f34f57a3 | 377 | int btrfs_xattr_security_init(struct btrfs_trans_handle *trans, |
2a7dba39 EP |
378 | struct inode *inode, struct inode *dir, |
379 | const struct qstr *qstr) | |
0279b4cd JO |
380 | { |
381 | int err; | |
382 | size_t len; | |
383 | void *value; | |
384 | char *suffix; | |
385 | char *name; | |
386 | ||
2a7dba39 EP |
387 | err = security_inode_init_security(inode, dir, qstr, &suffix, &value, |
388 | &len); | |
0279b4cd JO |
389 | if (err) { |
390 | if (err == -EOPNOTSUPP) | |
391 | return 0; | |
392 | return err; | |
393 | } | |
394 | ||
395 | name = kmalloc(XATTR_SECURITY_PREFIX_LEN + strlen(suffix) + 1, | |
396 | GFP_NOFS); | |
397 | if (!name) { | |
398 | err = -ENOMEM; | |
399 | } else { | |
400 | strcpy(name, XATTR_SECURITY_PREFIX); | |
401 | strcpy(name + XATTR_SECURITY_PREFIX_LEN, suffix); | |
f34f57a3 | 402 | err = __btrfs_setxattr(trans, inode, name, value, len, 0); |
0279b4cd JO |
403 | kfree(name); |
404 | } | |
405 | ||
406 | kfree(suffix); | |
407 | kfree(value); | |
408 | return err; | |
409 | } |