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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>
24#include <linux/security.h>
25#include "ctree.h"
26#include "btrfs_inode.h"
27#include "transaction.h"
28#include "xattr.h"
29#include "disk-io.h"
30
31
32ssize_t __btrfs_getxattr(struct inode *inode, const char *name,
33 void *buffer, size_t size)
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;
39 int ret = 0;
40 unsigned long data_ptr;
41
42 path = btrfs_alloc_path();
43 if (!path)
44 return -ENOMEM;
45
46 /* lookup the xattr by name */
47 di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(inode), name,
48 strlen(name), 0);
49 if (!di) {
50 ret = -ENODATA;
51 goto out;
52 } else if (IS_ERR(di)) {
53 ret = PTR_ERR(di);
54 goto out;
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 }
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 */
77 data_ptr = (unsigned long)((char *)(di + 1) +
78 btrfs_dir_name_len(leaf, di));
79 read_extent_buffer(leaf, buffer, data_ptr,
80 btrfs_dir_data_len(leaf, di));
81 ret = btrfs_dir_data_len(leaf, di);
82
83out:
84 btrfs_free_path(path);
85 return ret;
86}
87
88static int do_setxattr(struct btrfs_trans_handle *trans,
89 struct inode *inode, const char *name,
90 const void *value, size_t size, int flags)
91{
92 struct btrfs_dir_item *di;
93 struct btrfs_root *root = BTRFS_I(inode)->root;
94 struct btrfs_path *path;
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;
100
101 path = btrfs_alloc_path();
102 if (!path)
103 return -ENOMEM;
104
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;
113 goto out;
114 }
115 ret = btrfs_delete_one_dir_name(trans, root, path, di);
116 if (ret)
117 goto out;
118 btrfs_release_path(path);
119
120 /*
121 * remove the attribute
122 */
123 if (!value)
124 goto out;
125 }
126
127again:
128 ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(inode),
129 name, name_len, value, size);
130 if (ret == -EEXIST) {
131 if (flags & XATTR_CREATE)
132 goto out;
133 /*
134 * We can't use the path we already have since we won't have the
135 * proper locking for a delete, so release the path and
136 * re-lookup to delete the thing.
137 */
138 btrfs_release_path(path);
139 di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(inode),
140 name, name_len, -1);
141 if (IS_ERR(di)) {
142 ret = PTR_ERR(di);
143 goto out;
144 } else if (!di) {
145 /* Shouldn't happen but just in case... */
146 btrfs_release_path(path);
147 goto again;
148 }
149
150 ret = btrfs_delete_one_dir_name(trans, root, path, di);
151 if (ret)
152 goto out;
153
154 /*
155 * We have a value to set, so go back and try to insert it now.
156 */
157 if (value) {
158 btrfs_release_path(path);
159 goto again;
160 }
161 }
162out:
163 btrfs_free_path(path);
164 return ret;
165}
166
167/*
168 * @value: "" makes the attribute to empty, NULL removes it
169 */
170int __btrfs_setxattr(struct btrfs_trans_handle *trans,
171 struct inode *inode, const char *name,
172 const void *value, size_t size, int flags)
173{
174 struct btrfs_root *root = BTRFS_I(inode)->root;
175 int ret;
176
177 if (trans)
178 return do_setxattr(trans, inode, name, value, size, flags);
179
180 trans = btrfs_start_transaction(root, 2);
181 if (IS_ERR(trans))
182 return PTR_ERR(trans);
183
184 ret = do_setxattr(trans, inode, name, value, size, flags);
185 if (ret)
186 goto out;
187
188 inode->i_ctime = CURRENT_TIME;
189 ret = btrfs_update_inode(trans, root, inode);
190 BUG_ON(ret);
191out:
192 btrfs_end_transaction_throttle(trans, root);
193 return ret;
194}
195
196ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
197{
198 struct btrfs_key key, found_key;
199 struct inode *inode = dentry->d_inode;
200 struct btrfs_root *root = BTRFS_I(inode)->root;
201 struct btrfs_path *path;
202 struct extent_buffer *leaf;
203 struct btrfs_dir_item *di;
204 int ret = 0, slot;
205 size_t total_size = 0, size_left = size;
206 unsigned long name_ptr;
207 size_t name_len;
208
209 /*
210 * ok we want all objects associated with this id.
211 * NOTE: we set key.offset = 0; because we want to start with the
212 * first xattr that we find and walk forward
213 */
214 key.objectid = btrfs_ino(inode);
215 btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
216 key.offset = 0;
217
218 path = btrfs_alloc_path();
219 if (!path)
220 return -ENOMEM;
221 path->reada = 2;
222
223 /* search for our xattrs */
224 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
225 if (ret < 0)
226 goto err;
227
228 while (1) {
229 leaf = path->nodes[0];
230 slot = path->slots[0];
231
232 /* this is where we start walking through the path */
233 if (slot >= btrfs_header_nritems(leaf)) {
234 /*
235 * if we've reached the last slot in this leaf we need
236 * to go to the next leaf and reset everything
237 */
238 ret = btrfs_next_leaf(root, path);
239 if (ret < 0)
240 goto err;
241 else if (ret > 0)
242 break;
243 continue;
244 }
245
246 btrfs_item_key_to_cpu(leaf, &found_key, slot);
247
248 /* check to make sure this item is what we want */
249 if (found_key.objectid != key.objectid)
250 break;
251 if (btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY)
252 break;
253
254 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
255 if (verify_dir_item(root, leaf, di))
256 continue;
257
258 name_len = btrfs_dir_name_len(leaf, di);
259 total_size += name_len + 1;
260
261 /* we are just looking for how big our buffer needs to be */
262 if (!size)
263 goto next;
264
265 if (!buffer || (name_len + 1) > size_left) {
266 ret = -ERANGE;
267 goto err;
268 }
269
270 name_ptr = (unsigned long)(di + 1);
271 read_extent_buffer(leaf, buffer, name_ptr, name_len);
272 buffer[name_len] = '\0';
273
274 size_left -= name_len + 1;
275 buffer += name_len + 1;
276next:
277 path->slots[0]++;
278 }
279 ret = total_size;
280
281err:
282 btrfs_free_path(path);
283
284 return ret;
285}
286
287/*
288 * List of handlers for synthetic system.* attributes. All real ondisk
289 * attributes are handled directly.
290 */
291const struct xattr_handler *btrfs_xattr_handlers[] = {
292#ifdef CONFIG_BTRFS_FS_POSIX_ACL
293 &btrfs_xattr_acl_access_handler,
294 &btrfs_xattr_acl_default_handler,
295#endif
296 NULL,
297};
298
299/*
300 * Check if the attribute is in a supported namespace.
301 *
302 * This applied after the check for the synthetic attributes in the system
303 * namespace.
304 */
305static bool btrfs_is_valid_xattr(const char *name)
306{
307 return !strncmp(name, XATTR_SECURITY_PREFIX,
308 XATTR_SECURITY_PREFIX_LEN) ||
309 !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) ||
310 !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) ||
311 !strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);
312}
313
314ssize_t btrfs_getxattr(struct dentry *dentry, const char *name,
315 void *buffer, size_t size)
316{
317 /*
318 * If this is a request for a synthetic attribute in the system.*
319 * namespace use the generic infrastructure to resolve a handler
320 * for it via sb->s_xattr.
321 */
322 if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
323 return generic_getxattr(dentry, name, buffer, size);
324
325 if (!btrfs_is_valid_xattr(name))
326 return -EOPNOTSUPP;
327 return __btrfs_getxattr(dentry->d_inode, name, buffer, size);
328}
329
330int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value,
331 size_t size, int flags)
332{
333 struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root;
334
335 /*
336 * The permission on security.* and system.* is not checked
337 * in permission().
338 */
339 if (btrfs_root_readonly(root))
340 return -EROFS;
341
342 /*
343 * If this is a request for a synthetic attribute in the system.*
344 * namespace use the generic infrastructure to resolve a handler
345 * for it via sb->s_xattr.
346 */
347 if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
348 return generic_setxattr(dentry, name, value, size, flags);
349
350 if (!btrfs_is_valid_xattr(name))
351 return -EOPNOTSUPP;
352
353 if (size == 0)
354 value = ""; /* empty EA, do not remove */
355
356 return __btrfs_setxattr(NULL, dentry->d_inode, name, value, size,
357 flags);
358}
359
360int btrfs_removexattr(struct dentry *dentry, const char *name)
361{
362 struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root;
363
364 /*
365 * The permission on security.* and system.* is not checked
366 * in permission().
367 */
368 if (btrfs_root_readonly(root))
369 return -EROFS;
370
371 /*
372 * If this is a request for a synthetic attribute in the system.*
373 * namespace use the generic infrastructure to resolve a handler
374 * for it via sb->s_xattr.
375 */
376 if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
377 return generic_removexattr(dentry, name);
378
379 if (!btrfs_is_valid_xattr(name))
380 return -EOPNOTSUPP;
381
382 return __btrfs_setxattr(NULL, dentry->d_inode, name, NULL, 0,
383 XATTR_REPLACE);
384}
385
386int btrfs_xattr_security_init(struct btrfs_trans_handle *trans,
387 struct inode *inode, struct inode *dir,
388 const struct qstr *qstr)
389{
390 int err;
391 size_t len;
392 void *value;
393 char *suffix;
394 char *name;
395
396 err = security_inode_init_security(inode, dir, qstr, &suffix, &value,
397 &len);
398 if (err) {
399 if (err == -EOPNOTSUPP)
400 return 0;
401 return err;
402 }
403
404 name = kmalloc(XATTR_SECURITY_PREFIX_LEN + strlen(suffix) + 1,
405 GFP_NOFS);
406 if (!name) {
407 err = -ENOMEM;
408 } else {
409 strcpy(name, XATTR_SECURITY_PREFIX);
410 strcpy(name + XATTR_SECURITY_PREFIX_LEN, suffix);
411 err = __btrfs_setxattr(trans, inode, name, value, len, 0);
412 kfree(name);
413 }
414
415 kfree(suffix);
416 kfree(value);
417 return err;
418}
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>
24#include <linux/security.h>
25#include <linux/posix_acl_xattr.h>
26#include "ctree.h"
27#include "btrfs_inode.h"
28#include "transaction.h"
29#include "xattr.h"
30#include "disk-io.h"
31#include "props.h"
32
33
34ssize_t __btrfs_getxattr(struct inode *inode, const char *name,
35 void *buffer, size_t size)
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;
41 int ret = 0;
42 unsigned long data_ptr;
43
44 path = btrfs_alloc_path();
45 if (!path)
46 return -ENOMEM;
47
48 /* lookup the xattr by name */
49 di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(inode), name,
50 strlen(name), 0);
51 if (!di) {
52 ret = -ENODATA;
53 goto out;
54 } else if (IS_ERR(di)) {
55 ret = PTR_ERR(di);
56 goto out;
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 }
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 */
79 data_ptr = (unsigned long)((char *)(di + 1) +
80 btrfs_dir_name_len(leaf, di));
81 read_extent_buffer(leaf, buffer, data_ptr,
82 btrfs_dir_data_len(leaf, di));
83 ret = btrfs_dir_data_len(leaf, di);
84
85out:
86 btrfs_free_path(path);
87 return ret;
88}
89
90static int do_setxattr(struct btrfs_trans_handle *trans,
91 struct inode *inode, const char *name,
92 const void *value, size_t size, int flags)
93{
94 struct btrfs_dir_item *di;
95 struct btrfs_root *root = BTRFS_I(inode)->root;
96 struct btrfs_path *path;
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;
102
103 path = btrfs_alloc_path();
104 if (!path)
105 return -ENOMEM;
106
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;
115 goto out;
116 }
117 ret = btrfs_delete_one_dir_name(trans, root, path, di);
118 if (ret)
119 goto out;
120 btrfs_release_path(path);
121
122 /*
123 * remove the attribute
124 */
125 if (!value)
126 goto out;
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);
137 }
138
139again:
140 ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(inode),
141 name, name_len, value, size);
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
153 if (ret == -EEXIST) {
154 if (flags & XATTR_CREATE)
155 goto out;
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 */
161 btrfs_release_path(path);
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 }
172
173 ret = btrfs_delete_one_dir_name(trans, root, path, di);
174 if (ret)
175 goto out;
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;
183 }
184 }
185out:
186 btrfs_free_path(path);
187 return ret;
188}
189
190/*
191 * @value: "" makes the attribute to empty, NULL removes it
192 */
193int __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
203 trans = btrfs_start_transaction(root, 2);
204 if (IS_ERR(trans))
205 return PTR_ERR(trans);
206
207 ret = do_setxattr(trans, inode, name, value, size, flags);
208 if (ret)
209 goto out;
210
211 inode_inc_iversion(inode);
212 inode->i_ctime = CURRENT_TIME;
213 set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
214 ret = btrfs_update_inode(trans, root, inode);
215 BUG_ON(ret);
216out:
217 btrfs_end_transaction(trans, root);
218 return ret;
219}
220
221ssize_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;
227 struct extent_buffer *leaf;
228 struct btrfs_dir_item *di;
229 int ret = 0, slot;
230 size_t total_size = 0, size_left = size;
231 unsigned long name_ptr;
232 size_t name_len;
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 */
239 key.objectid = btrfs_ino(inode);
240 btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
241 key.offset = 0;
242
243 path = btrfs_alloc_path();
244 if (!path)
245 return -ENOMEM;
246 path->reada = 2;
247
248 /* search for our xattrs */
249 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
250 if (ret < 0)
251 goto err;
252
253 while (1) {
254 leaf = path->nodes[0];
255 slot = path->slots[0];
256
257 /* this is where we start walking through the path */
258 if (slot >= btrfs_header_nritems(leaf)) {
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 */
263 ret = btrfs_next_leaf(root, path);
264 if (ret < 0)
265 goto err;
266 else if (ret > 0)
267 break;
268 continue;
269 }
270
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;
276 if (btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY)
277 break;
278
279 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
280 if (verify_dir_item(root, leaf, di))
281 goto next;
282
283 name_len = btrfs_dir_name_len(leaf, di);
284 total_size += name_len + 1;
285
286 /* we are just looking for how big our buffer needs to be */
287 if (!size)
288 goto next;
289
290 if (!buffer || (name_len + 1) > size_left) {
291 ret = -ERANGE;
292 goto err;
293 }
294
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;
301next:
302 path->slots[0]++;
303 }
304 ret = total_size;
305
306err:
307 btrfs_free_path(path);
308
309 return ret;
310}
311
312/*
313 * List of handlers for synthetic system.* attributes. All real ondisk
314 * attributes are handled directly.
315 */
316const struct xattr_handler *btrfs_xattr_handlers[] = {
317#ifdef CONFIG_BTRFS_FS_POSIX_ACL
318 &posix_acl_access_xattr_handler,
319 &posix_acl_default_xattr_handler,
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.
329 */
330static bool btrfs_is_valid_xattr(const char *name)
331{
332 return !strncmp(name, XATTR_SECURITY_PREFIX,
333 XATTR_SECURITY_PREFIX_LEN) ||
334 !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) ||
335 !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) ||
336 !strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN) ||
337 !strncmp(name, XATTR_BTRFS_PREFIX, XATTR_BTRFS_PREFIX_LEN);
338}
339
340ssize_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);
350
351 if (!btrfs_is_valid_xattr(name))
352 return -EOPNOTSUPP;
353 return __btrfs_getxattr(dentry->d_inode, name, buffer, size);
354}
355
356int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value,
357 size_t size, int flags)
358{
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
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);
375
376 if (!btrfs_is_valid_xattr(name))
377 return -EOPNOTSUPP;
378
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
383 if (size == 0)
384 value = ""; /* empty EA, do not remove */
385
386 return __btrfs_setxattr(NULL, dentry->d_inode, name, value, size,
387 flags);
388}
389
390int btrfs_removexattr(struct dentry *dentry, const char *name)
391{
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
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;
411
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
416 return __btrfs_setxattr(NULL, dentry->d_inode, name, NULL, 0,
417 XATTR_REPLACE);
418}
419
420static int btrfs_initxattrs(struct inode *inode,
421 const struct xattr *xattr_array, void *fs_info)
422{
423 const struct xattr *xattr;
424 struct btrfs_trans_handle *trans = fs_info;
425 char *name;
426 int err = 0;
427
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 }
435 strcpy(name, XATTR_SECURITY_PREFIX);
436 strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
437 err = __btrfs_setxattr(trans, inode, name,
438 xattr->value, xattr->value_len, 0);
439 kfree(name);
440 if (err < 0)
441 break;
442 }
443 return err;
444}
445
446int 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}