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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2007 Red Hat. All rights reserved.
4 */
5
6#include <linux/init.h>
7#include <linux/fs.h>
8#include <linux/slab.h>
9#include <linux/rwsem.h>
10#include <linux/xattr.h>
11#include <linux/security.h>
12#include <linux/posix_acl_xattr.h>
13#include <linux/iversion.h>
14#include "ctree.h"
15#include "btrfs_inode.h"
16#include "transaction.h"
17#include "xattr.h"
18#include "disk-io.h"
19#include "props.h"
20#include "locking.h"
21
22int btrfs_getxattr(struct inode *inode, const char *name,
23 void *buffer, size_t size)
24{
25 struct btrfs_dir_item *di;
26 struct btrfs_root *root = BTRFS_I(inode)->root;
27 struct btrfs_path *path;
28 struct extent_buffer *leaf;
29 int ret = 0;
30 unsigned long data_ptr;
31
32 path = btrfs_alloc_path();
33 if (!path)
34 return -ENOMEM;
35
36 /* lookup the xattr by name */
37 di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(BTRFS_I(inode)),
38 name, strlen(name), 0);
39 if (!di) {
40 ret = -ENODATA;
41 goto out;
42 } else if (IS_ERR(di)) {
43 ret = PTR_ERR(di);
44 goto out;
45 }
46
47 leaf = path->nodes[0];
48 /* if size is 0, that means we want the size of the attr */
49 if (!size) {
50 ret = btrfs_dir_data_len(leaf, di);
51 goto out;
52 }
53
54 /* now get the data out of our dir_item */
55 if (btrfs_dir_data_len(leaf, di) > size) {
56 ret = -ERANGE;
57 goto out;
58 }
59
60 /*
61 * The way things are packed into the leaf is like this
62 * |struct btrfs_dir_item|name|data|
63 * where name is the xattr name, so security.foo, and data is the
64 * content of the xattr. data_ptr points to the location in memory
65 * where the data starts in the in memory leaf
66 */
67 data_ptr = (unsigned long)((char *)(di + 1) +
68 btrfs_dir_name_len(leaf, di));
69 read_extent_buffer(leaf, buffer, data_ptr,
70 btrfs_dir_data_len(leaf, di));
71 ret = btrfs_dir_data_len(leaf, di);
72
73out:
74 btrfs_free_path(path);
75 return ret;
76}
77
78static int do_setxattr(struct btrfs_trans_handle *trans,
79 struct inode *inode, const char *name,
80 const void *value, size_t size, int flags)
81{
82 struct btrfs_dir_item *di = NULL;
83 struct btrfs_root *root = BTRFS_I(inode)->root;
84 struct btrfs_fs_info *fs_info = root->fs_info;
85 struct btrfs_path *path;
86 size_t name_len = strlen(name);
87 int ret = 0;
88
89 if (name_len + size > BTRFS_MAX_XATTR_SIZE(root->fs_info))
90 return -ENOSPC;
91
92 path = btrfs_alloc_path();
93 if (!path)
94 return -ENOMEM;
95 path->skip_release_on_error = 1;
96
97 if (!value) {
98 di = btrfs_lookup_xattr(trans, root, path,
99 btrfs_ino(BTRFS_I(inode)), name, name_len, -1);
100 if (!di && (flags & XATTR_REPLACE))
101 ret = -ENODATA;
102 else if (IS_ERR(di))
103 ret = PTR_ERR(di);
104 else if (di)
105 ret = btrfs_delete_one_dir_name(trans, root, path, di);
106 goto out;
107 }
108
109 /*
110 * For a replace we can't just do the insert blindly.
111 * Do a lookup first (read-only btrfs_search_slot), and return if xattr
112 * doesn't exist. If it exists, fall down below to the insert/replace
113 * path - we can't race with a concurrent xattr delete, because the VFS
114 * locks the inode's i_mutex before calling setxattr or removexattr.
115 */
116 if (flags & XATTR_REPLACE) {
117 ASSERT(inode_is_locked(inode));
118 di = btrfs_lookup_xattr(NULL, root, path,
119 btrfs_ino(BTRFS_I(inode)), name, name_len, 0);
120 if (!di)
121 ret = -ENODATA;
122 else if (IS_ERR(di))
123 ret = PTR_ERR(di);
124 if (ret)
125 goto out;
126 btrfs_release_path(path);
127 di = NULL;
128 }
129
130 ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(BTRFS_I(inode)),
131 name, name_len, value, size);
132 if (ret == -EOVERFLOW) {
133 /*
134 * We have an existing item in a leaf, split_leaf couldn't
135 * expand it. That item might have or not a dir_item that
136 * matches our target xattr, so lets check.
137 */
138 ret = 0;
139 btrfs_assert_tree_locked(path->nodes[0]);
140 di = btrfs_match_dir_item_name(fs_info, path, name, name_len);
141 if (!di && !(flags & XATTR_REPLACE)) {
142 ret = -ENOSPC;
143 goto out;
144 }
145 } else if (ret == -EEXIST) {
146 ret = 0;
147 di = btrfs_match_dir_item_name(fs_info, path, name, name_len);
148 ASSERT(di); /* logic error */
149 } else if (ret) {
150 goto out;
151 }
152
153 if (di && (flags & XATTR_CREATE)) {
154 ret = -EEXIST;
155 goto out;
156 }
157
158 if (di) {
159 /*
160 * We're doing a replace, and it must be atomic, that is, at
161 * any point in time we have either the old or the new xattr
162 * value in the tree. We don't want readers (getxattr and
163 * listxattrs) to miss a value, this is specially important
164 * for ACLs.
165 */
166 const int slot = path->slots[0];
167 struct extent_buffer *leaf = path->nodes[0];
168 const u16 old_data_len = btrfs_dir_data_len(leaf, di);
169 const u32 item_size = btrfs_item_size_nr(leaf, slot);
170 const u32 data_size = sizeof(*di) + name_len + size;
171 struct btrfs_item *item;
172 unsigned long data_ptr;
173 char *ptr;
174
175 if (size > old_data_len) {
176 if (btrfs_leaf_free_space(fs_info, leaf) <
177 (size - old_data_len)) {
178 ret = -ENOSPC;
179 goto out;
180 }
181 }
182
183 if (old_data_len + name_len + sizeof(*di) == item_size) {
184 /* No other xattrs packed in the same leaf item. */
185 if (size > old_data_len)
186 btrfs_extend_item(fs_info, path,
187 size - old_data_len);
188 else if (size < old_data_len)
189 btrfs_truncate_item(fs_info, path,
190 data_size, 1);
191 } else {
192 /* There are other xattrs packed in the same item. */
193 ret = btrfs_delete_one_dir_name(trans, root, path, di);
194 if (ret)
195 goto out;
196 btrfs_extend_item(fs_info, path, data_size);
197 }
198
199 item = btrfs_item_nr(slot);
200 ptr = btrfs_item_ptr(leaf, slot, char);
201 ptr += btrfs_item_size(leaf, item) - data_size;
202 di = (struct btrfs_dir_item *)ptr;
203 btrfs_set_dir_data_len(leaf, di, size);
204 data_ptr = ((unsigned long)(di + 1)) + name_len;
205 write_extent_buffer(leaf, value, data_ptr, size);
206 btrfs_mark_buffer_dirty(leaf);
207 } else {
208 /*
209 * Insert, and we had space for the xattr, so path->slots[0] is
210 * where our xattr dir_item is and btrfs_insert_xattr_item()
211 * filled it.
212 */
213 }
214out:
215 btrfs_free_path(path);
216 return ret;
217}
218
219/*
220 * @value: "" makes the attribute to empty, NULL removes it
221 */
222int btrfs_setxattr(struct btrfs_trans_handle *trans,
223 struct inode *inode, const char *name,
224 const void *value, size_t size, int flags)
225{
226 struct btrfs_root *root = BTRFS_I(inode)->root;
227 int ret;
228
229 if (btrfs_root_readonly(root))
230 return -EROFS;
231
232 if (trans)
233 return do_setxattr(trans, inode, name, value, size, flags);
234
235 trans = btrfs_start_transaction(root, 2);
236 if (IS_ERR(trans))
237 return PTR_ERR(trans);
238
239 ret = do_setxattr(trans, inode, name, value, size, flags);
240 if (ret)
241 goto out;
242
243 inode_inc_iversion(inode);
244 inode->i_ctime = current_time(inode);
245 set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
246 ret = btrfs_update_inode(trans, root, inode);
247 BUG_ON(ret);
248out:
249 btrfs_end_transaction(trans);
250 return ret;
251}
252
253ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
254{
255 struct btrfs_key key;
256 struct inode *inode = d_inode(dentry);
257 struct btrfs_root *root = BTRFS_I(inode)->root;
258 struct btrfs_path *path;
259 int ret = 0;
260 size_t total_size = 0, size_left = size;
261
262 /*
263 * ok we want all objects associated with this id.
264 * NOTE: we set key.offset = 0; because we want to start with the
265 * first xattr that we find and walk forward
266 */
267 key.objectid = btrfs_ino(BTRFS_I(inode));
268 key.type = BTRFS_XATTR_ITEM_KEY;
269 key.offset = 0;
270
271 path = btrfs_alloc_path();
272 if (!path)
273 return -ENOMEM;
274 path->reada = READA_FORWARD;
275
276 /* search for our xattrs */
277 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
278 if (ret < 0)
279 goto err;
280
281 while (1) {
282 struct extent_buffer *leaf;
283 int slot;
284 struct btrfs_dir_item *di;
285 struct btrfs_key found_key;
286 u32 item_size;
287 u32 cur;
288
289 leaf = path->nodes[0];
290 slot = path->slots[0];
291
292 /* this is where we start walking through the path */
293 if (slot >= btrfs_header_nritems(leaf)) {
294 /*
295 * if we've reached the last slot in this leaf we need
296 * to go to the next leaf and reset everything
297 */
298 ret = btrfs_next_leaf(root, path);
299 if (ret < 0)
300 goto err;
301 else if (ret > 0)
302 break;
303 continue;
304 }
305
306 btrfs_item_key_to_cpu(leaf, &found_key, slot);
307
308 /* check to make sure this item is what we want */
309 if (found_key.objectid != key.objectid)
310 break;
311 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
312 break;
313 if (found_key.type < BTRFS_XATTR_ITEM_KEY)
314 goto next_item;
315
316 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
317 item_size = btrfs_item_size_nr(leaf, slot);
318 cur = 0;
319 while (cur < item_size) {
320 u16 name_len = btrfs_dir_name_len(leaf, di);
321 u16 data_len = btrfs_dir_data_len(leaf, di);
322 u32 this_len = sizeof(*di) + name_len + data_len;
323 unsigned long name_ptr = (unsigned long)(di + 1);
324
325 total_size += name_len + 1;
326 /*
327 * We are just looking for how big our buffer needs to
328 * be.
329 */
330 if (!size)
331 goto next;
332
333 if (!buffer || (name_len + 1) > size_left) {
334 ret = -ERANGE;
335 goto err;
336 }
337
338 read_extent_buffer(leaf, buffer, name_ptr, name_len);
339 buffer[name_len] = '\0';
340
341 size_left -= name_len + 1;
342 buffer += name_len + 1;
343next:
344 cur += this_len;
345 di = (struct btrfs_dir_item *)((char *)di + this_len);
346 }
347next_item:
348 path->slots[0]++;
349 }
350 ret = total_size;
351
352err:
353 btrfs_free_path(path);
354
355 return ret;
356}
357
358static int btrfs_xattr_handler_get(const struct xattr_handler *handler,
359 struct dentry *unused, struct inode *inode,
360 const char *name, void *buffer, size_t size)
361{
362 name = xattr_full_name(handler, name);
363 return btrfs_getxattr(inode, name, buffer, size);
364}
365
366static int btrfs_xattr_handler_set(const struct xattr_handler *handler,
367 struct dentry *unused, struct inode *inode,
368 const char *name, const void *buffer,
369 size_t size, int flags)
370{
371 name = xattr_full_name(handler, name);
372 return btrfs_setxattr(NULL, inode, name, buffer, size, flags);
373}
374
375static int btrfs_xattr_handler_set_prop(const struct xattr_handler *handler,
376 struct dentry *unused, struct inode *inode,
377 const char *name, const void *value,
378 size_t size, int flags)
379{
380 name = xattr_full_name(handler, name);
381 return btrfs_set_prop(inode, name, value, size, flags);
382}
383
384static const struct xattr_handler btrfs_security_xattr_handler = {
385 .prefix = XATTR_SECURITY_PREFIX,
386 .get = btrfs_xattr_handler_get,
387 .set = btrfs_xattr_handler_set,
388};
389
390static const struct xattr_handler btrfs_trusted_xattr_handler = {
391 .prefix = XATTR_TRUSTED_PREFIX,
392 .get = btrfs_xattr_handler_get,
393 .set = btrfs_xattr_handler_set,
394};
395
396static const struct xattr_handler btrfs_user_xattr_handler = {
397 .prefix = XATTR_USER_PREFIX,
398 .get = btrfs_xattr_handler_get,
399 .set = btrfs_xattr_handler_set,
400};
401
402static const struct xattr_handler btrfs_btrfs_xattr_handler = {
403 .prefix = XATTR_BTRFS_PREFIX,
404 .get = btrfs_xattr_handler_get,
405 .set = btrfs_xattr_handler_set_prop,
406};
407
408const struct xattr_handler *btrfs_xattr_handlers[] = {
409 &btrfs_security_xattr_handler,
410#ifdef CONFIG_BTRFS_FS_POSIX_ACL
411 &posix_acl_access_xattr_handler,
412 &posix_acl_default_xattr_handler,
413#endif
414 &btrfs_trusted_xattr_handler,
415 &btrfs_user_xattr_handler,
416 &btrfs_btrfs_xattr_handler,
417 NULL,
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_KERNEL);
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, xattr->value,
438 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}
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}