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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 JB |
46 | /* lookup the xattr by name */ |
47 | di = btrfs_lookup_xattr(NULL, root, path, inode->i_ino, name, | |
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 | |
5103e947 JB |
105 | /* first lets see if we already have this xattr */ |
106 | di = btrfs_lookup_xattr(trans, root, path, inode->i_ino, name, | |
107 | strlen(name), -1); | |
108 | if (IS_ERR(di)) { | |
109 | ret = PTR_ERR(di); | |
110 | goto out; | |
111 | } | |
112 | ||
113 | /* ok we already have this xattr, lets remove it */ | |
114 | if (di) { | |
115 | /* if we want create only exit */ | |
116 | if (flags & XATTR_CREATE) { | |
117 | ret = -EEXIST; | |
118 | goto out; | |
119 | } | |
120 | ||
121 | ret = btrfs_delete_one_dir_name(trans, root, path, di); | |
f34f57a3 | 122 | BUG_ON(ret); |
5103e947 JB |
123 | btrfs_release_path(root, path); |
124 | ||
125 | /* if we don't have a value then we are removing the xattr */ | |
f34f57a3 | 126 | if (!value) |
5103e947 | 127 | goto out; |
33268eaf JB |
128 | } else { |
129 | btrfs_release_path(root, path); | |
130 | ||
131 | if (flags & XATTR_REPLACE) { | |
132 | /* we couldn't find the attr to replace */ | |
133 | ret = -ENODATA; | |
134 | goto out; | |
135 | } | |
5103e947 JB |
136 | } |
137 | ||
138 | /* ok we have to create a completely new xattr */ | |
f34f57a3 YZ |
139 | ret = btrfs_insert_xattr_item(trans, root, path, inode->i_ino, |
140 | name, name_len, value, size); | |
141 | BUG_ON(ret); | |
142 | out: | |
143 | btrfs_free_path(path); | |
144 | return ret; | |
145 | } | |
146 | ||
147 | int __btrfs_setxattr(struct btrfs_trans_handle *trans, | |
148 | struct inode *inode, const char *name, | |
149 | const void *value, size_t size, int flags) | |
150 | { | |
151 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
152 | int ret; | |
153 | ||
154 | if (trans) | |
155 | return do_setxattr(trans, inode, name, value, size, flags); | |
156 | ||
157 | ret = btrfs_reserve_metadata_space(root, 2); | |
5103e947 | 158 | if (ret) |
f34f57a3 | 159 | return ret; |
5103e947 | 160 | |
f34f57a3 YZ |
161 | trans = btrfs_start_transaction(root, 1); |
162 | if (!trans) { | |
163 | ret = -ENOMEM; | |
164 | goto out; | |
5103e947 | 165 | } |
f34f57a3 | 166 | btrfs_set_trans_block_group(trans, inode); |
5103e947 | 167 | |
f34f57a3 YZ |
168 | ret = do_setxattr(trans, inode, name, value, size, flags); |
169 | if (ret) | |
170 | goto out; | |
171 | ||
172 | inode->i_ctime = CURRENT_TIME; | |
173 | ret = btrfs_update_inode(trans, root, inode); | |
174 | BUG_ON(ret); | |
175 | out: | |
176 | btrfs_end_transaction_throttle(trans, root); | |
177 | btrfs_unreserve_metadata_space(root, 2); | |
5103e947 JB |
178 | return ret; |
179 | } | |
180 | ||
181 | ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size) | |
182 | { | |
183 | struct btrfs_key key, found_key; | |
184 | struct inode *inode = dentry->d_inode; | |
185 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
186 | struct btrfs_path *path; | |
187 | struct btrfs_item *item; | |
188 | struct extent_buffer *leaf; | |
189 | struct btrfs_dir_item *di; | |
5103e947 | 190 | int ret = 0, slot, advance; |
eaa47d86 | 191 | size_t total_size = 0, size_left = size; |
5103e947 | 192 | unsigned long name_ptr; |
eaa47d86 | 193 | size_t name_len; |
5103e947 JB |
194 | u32 nritems; |
195 | ||
196 | /* | |
197 | * ok we want all objects associated with this id. | |
198 | * NOTE: we set key.offset = 0; because we want to start with the | |
199 | * first xattr that we find and walk forward | |
200 | */ | |
201 | key.objectid = inode->i_ino; | |
202 | btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY); | |
203 | key.offset = 0; | |
204 | ||
205 | path = btrfs_alloc_path(); | |
5103e947 JB |
206 | if (!path) |
207 | return -ENOMEM; | |
1caf9342 | 208 | path->reada = 2; |
5103e947 | 209 | |
5103e947 JB |
210 | /* search for our xattrs */ |
211 | ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); | |
212 | if (ret < 0) | |
213 | goto err; | |
5103e947 JB |
214 | advance = 0; |
215 | while (1) { | |
216 | leaf = path->nodes[0]; | |
217 | nritems = btrfs_header_nritems(leaf); | |
218 | slot = path->slots[0]; | |
219 | ||
220 | /* this is where we start walking through the path */ | |
221 | if (advance || slot >= nritems) { | |
222 | /* | |
223 | * if we've reached the last slot in this leaf we need | |
224 | * to go to the next leaf and reset everything | |
225 | */ | |
226 | if (slot >= nritems-1) { | |
227 | ret = btrfs_next_leaf(root, path); | |
228 | if (ret) | |
229 | break; | |
230 | leaf = path->nodes[0]; | |
231 | nritems = btrfs_header_nritems(leaf); | |
232 | slot = path->slots[0]; | |
233 | } else { | |
234 | /* | |
235 | * just walking through the slots on this leaf | |
236 | */ | |
237 | slot++; | |
238 | path->slots[0]++; | |
239 | } | |
240 | } | |
241 | advance = 1; | |
242 | ||
243 | item = btrfs_item_nr(leaf, slot); | |
244 | btrfs_item_key_to_cpu(leaf, &found_key, slot); | |
245 | ||
246 | /* check to make sure this item is what we want */ | |
247 | if (found_key.objectid != key.objectid) | |
248 | break; | |
249 | if (btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY) | |
250 | break; | |
251 | ||
252 | di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item); | |
253 | ||
eaa47d86 CH |
254 | name_len = btrfs_dir_name_len(leaf, di); |
255 | total_size += name_len + 1; | |
5103e947 JB |
256 | |
257 | /* we are just looking for how big our buffer needs to be */ | |
258 | if (!size) | |
259 | continue; | |
260 | ||
eaa47d86 | 261 | if (!buffer || (name_len + 1) > size_left) { |
5103e947 | 262 | ret = -ERANGE; |
b16281c3 | 263 | goto err; |
5103e947 JB |
264 | } |
265 | ||
eaa47d86 CH |
266 | name_ptr = (unsigned long)(di + 1); |
267 | read_extent_buffer(leaf, buffer, name_ptr, name_len); | |
268 | buffer[name_len] = '\0'; | |
269 | ||
270 | size_left -= name_len + 1; | |
271 | buffer += name_len + 1; | |
5103e947 JB |
272 | } |
273 | ret = total_size; | |
274 | ||
275 | err: | |
5103e947 JB |
276 | btrfs_free_path(path); |
277 | ||
278 | return ret; | |
279 | } | |
280 | ||
5103e947 | 281 | /* |
95819c05 CH |
282 | * List of handlers for synthetic system.* attributes. All real ondisk |
283 | * attributes are handled directly. | |
284 | */ | |
285 | struct xattr_handler *btrfs_xattr_handlers[] = { | |
0eda294d | 286 | #ifdef CONFIG_BTRFS_FS_POSIX_ACL |
95819c05 CH |
287 | &btrfs_xattr_acl_access_handler, |
288 | &btrfs_xattr_acl_default_handler, | |
289 | #endif | |
290 | NULL, | |
291 | }; | |
292 | ||
293 | /* | |
294 | * Check if the attribute is in a supported namespace. | |
295 | * | |
296 | * This applied after the check for the synthetic attributes in the system | |
297 | * namespace. | |
5103e947 | 298 | */ |
95819c05 CH |
299 | static bool btrfs_is_valid_xattr(const char *name) |
300 | { | |
d397712b CM |
301 | return !strncmp(name, XATTR_SECURITY_PREFIX, |
302 | XATTR_SECURITY_PREFIX_LEN) || | |
95819c05 CH |
303 | !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) || |
304 | !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) || | |
305 | !strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN); | |
69a32ac5 CM |
306 | } |
307 | ||
95819c05 CH |
308 | ssize_t btrfs_getxattr(struct dentry *dentry, const char *name, |
309 | void *buffer, size_t size) | |
310 | { | |
311 | /* | |
312 | * If this is a request for a synthetic attribute in the system.* | |
313 | * namespace use the generic infrastructure to resolve a handler | |
314 | * for it via sb->s_xattr. | |
315 | */ | |
316 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
317 | return generic_getxattr(dentry, name, buffer, size); | |
5103e947 | 318 | |
95819c05 CH |
319 | if (!btrfs_is_valid_xattr(name)) |
320 | return -EOPNOTSUPP; | |
321 | return __btrfs_getxattr(dentry->d_inode, name, buffer, size); | |
322 | } | |
5103e947 | 323 | |
95819c05 CH |
324 | int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value, |
325 | size_t size, int flags) | |
326 | { | |
327 | /* | |
328 | * If this is a request for a synthetic attribute in the system.* | |
329 | * namespace use the generic infrastructure to resolve a handler | |
330 | * for it via sb->s_xattr. | |
331 | */ | |
332 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
333 | return generic_setxattr(dentry, name, value, size, flags); | |
5103e947 | 334 | |
95819c05 CH |
335 | if (!btrfs_is_valid_xattr(name)) |
336 | return -EOPNOTSUPP; | |
5103e947 | 337 | |
95819c05 CH |
338 | if (size == 0) |
339 | value = ""; /* empty EA, do not remove */ | |
f34f57a3 YZ |
340 | |
341 | return __btrfs_setxattr(NULL, dentry->d_inode, name, value, size, | |
342 | flags); | |
95819c05 CH |
343 | } |
344 | ||
345 | int btrfs_removexattr(struct dentry *dentry, const char *name) | |
346 | { | |
347 | /* | |
348 | * If this is a request for a synthetic attribute in the system.* | |
349 | * namespace use the generic infrastructure to resolve a handler | |
350 | * for it via sb->s_xattr. | |
351 | */ | |
352 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
353 | return generic_removexattr(dentry, name); | |
354 | ||
355 | if (!btrfs_is_valid_xattr(name)) | |
356 | return -EOPNOTSUPP; | |
f34f57a3 YZ |
357 | |
358 | return __btrfs_setxattr(NULL, dentry->d_inode, name, NULL, 0, | |
359 | XATTR_REPLACE); | |
95819c05 | 360 | } |
0279b4cd | 361 | |
f34f57a3 YZ |
362 | int btrfs_xattr_security_init(struct btrfs_trans_handle *trans, |
363 | struct inode *inode, struct inode *dir) | |
0279b4cd JO |
364 | { |
365 | int err; | |
366 | size_t len; | |
367 | void *value; | |
368 | char *suffix; | |
369 | char *name; | |
370 | ||
371 | err = security_inode_init_security(inode, dir, &suffix, &value, &len); | |
372 | if (err) { | |
373 | if (err == -EOPNOTSUPP) | |
374 | return 0; | |
375 | return err; | |
376 | } | |
377 | ||
378 | name = kmalloc(XATTR_SECURITY_PREFIX_LEN + strlen(suffix) + 1, | |
379 | GFP_NOFS); | |
380 | if (!name) { | |
381 | err = -ENOMEM; | |
382 | } else { | |
383 | strcpy(name, XATTR_SECURITY_PREFIX); | |
384 | strcpy(name + XATTR_SECURITY_PREFIX_LEN, suffix); | |
f34f57a3 | 385 | err = __btrfs_setxattr(trans, inode, name, value, len, 0); |
0279b4cd JO |
386 | kfree(name); |
387 | } | |
388 | ||
389 | kfree(suffix); | |
390 | kfree(value); | |
391 | return err; | |
392 | } |