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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// 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 <linux/sched/mm.h>
15#include "ctree.h"
16#include "btrfs_inode.h"
17#include "transaction.h"
18#include "xattr.h"
19#include "disk-io.h"
20#include "props.h"
21#include "locking.h"
22
23int btrfs_getxattr(struct inode *inode, const char *name,
24 void *buffer, size_t size)
25{
26 struct btrfs_dir_item *di;
27 struct btrfs_root *root = BTRFS_I(inode)->root;
28 struct btrfs_path *path;
29 struct extent_buffer *leaf;
30 int ret = 0;
31 unsigned long data_ptr;
32
33 path = btrfs_alloc_path();
34 if (!path)
35 return -ENOMEM;
36
37 /* lookup the xattr by name */
38 di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(BTRFS_I(inode)),
39 name, strlen(name), 0);
40 if (!di) {
41 ret = -ENODATA;
42 goto out;
43 } else if (IS_ERR(di)) {
44 ret = PTR_ERR(di);
45 goto out;
46 }
47
48 leaf = path->nodes[0];
49 /* if size is 0, that means we want the size of the attr */
50 if (!size) {
51 ret = btrfs_dir_data_len(leaf, di);
52 goto out;
53 }
54
55 /* now get the data out of our dir_item */
56 if (btrfs_dir_data_len(leaf, di) > size) {
57 ret = -ERANGE;
58 goto out;
59 }
60
61 /*
62 * The way things are packed into the leaf is like this
63 * |struct btrfs_dir_item|name|data|
64 * where name is the xattr name, so security.foo, and data is the
65 * content of the xattr. data_ptr points to the location in memory
66 * where the data starts in the in memory leaf
67 */
68 data_ptr = (unsigned long)((char *)(di + 1) +
69 btrfs_dir_name_len(leaf, di));
70 read_extent_buffer(leaf, buffer, data_ptr,
71 btrfs_dir_data_len(leaf, di));
72 ret = btrfs_dir_data_len(leaf, di);
73
74out:
75 btrfs_free_path(path);
76 return ret;
77}
78
79int btrfs_setxattr(struct btrfs_trans_handle *trans, struct inode *inode,
80 const char *name, 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 ASSERT(trans);
90
91 if (name_len + size > BTRFS_MAX_XATTR_SIZE(root->fs_info))
92 return -ENOSPC;
93
94 path = btrfs_alloc_path();
95 if (!path)
96 return -ENOMEM;
97 path->skip_release_on_error = 1;
98
99 if (!value) {
100 di = btrfs_lookup_xattr(trans, root, path,
101 btrfs_ino(BTRFS_I(inode)), name, name_len, -1);
102 if (!di && (flags & XATTR_REPLACE))
103 ret = -ENODATA;
104 else if (IS_ERR(di))
105 ret = PTR_ERR(di);
106 else if (di)
107 ret = btrfs_delete_one_dir_name(trans, root, path, di);
108 goto out;
109 }
110
111 /*
112 * For a replace we can't just do the insert blindly.
113 * Do a lookup first (read-only btrfs_search_slot), and return if xattr
114 * doesn't exist. If it exists, fall down below to the insert/replace
115 * path - we can't race with a concurrent xattr delete, because the VFS
116 * locks the inode's i_mutex before calling setxattr or removexattr.
117 */
118 if (flags & XATTR_REPLACE) {
119 ASSERT(inode_is_locked(inode));
120 di = btrfs_lookup_xattr(NULL, root, path,
121 btrfs_ino(BTRFS_I(inode)), name, name_len, 0);
122 if (!di)
123 ret = -ENODATA;
124 else if (IS_ERR(di))
125 ret = PTR_ERR(di);
126 if (ret)
127 goto out;
128 btrfs_release_path(path);
129 di = NULL;
130 }
131
132 ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(BTRFS_I(inode)),
133 name, name_len, value, size);
134 if (ret == -EOVERFLOW) {
135 /*
136 * We have an existing item in a leaf, split_leaf couldn't
137 * expand it. That item might have or not a dir_item that
138 * matches our target xattr, so lets check.
139 */
140 ret = 0;
141 btrfs_assert_tree_locked(path->nodes[0]);
142 di = btrfs_match_dir_item_name(fs_info, path, name, name_len);
143 if (!di && !(flags & XATTR_REPLACE)) {
144 ret = -ENOSPC;
145 goto out;
146 }
147 } else if (ret == -EEXIST) {
148 ret = 0;
149 di = btrfs_match_dir_item_name(fs_info, path, name, name_len);
150 ASSERT(di); /* logic error */
151 } else if (ret) {
152 goto out;
153 }
154
155 if (di && (flags & XATTR_CREATE)) {
156 ret = -EEXIST;
157 goto out;
158 }
159
160 if (di) {
161 /*
162 * We're doing a replace, and it must be atomic, that is, at
163 * any point in time we have either the old or the new xattr
164 * value in the tree. We don't want readers (getxattr and
165 * listxattrs) to miss a value, this is specially important
166 * for ACLs.
167 */
168 const int slot = path->slots[0];
169 struct extent_buffer *leaf = path->nodes[0];
170 const u16 old_data_len = btrfs_dir_data_len(leaf, di);
171 const u32 item_size = btrfs_item_size_nr(leaf, slot);
172 const u32 data_size = sizeof(*di) + name_len + size;
173 struct btrfs_item *item;
174 unsigned long data_ptr;
175 char *ptr;
176
177 if (size > old_data_len) {
178 if (btrfs_leaf_free_space(leaf) <
179 (size - old_data_len)) {
180 ret = -ENOSPC;
181 goto out;
182 }
183 }
184
185 if (old_data_len + name_len + sizeof(*di) == item_size) {
186 /* No other xattrs packed in the same leaf item. */
187 if (size > old_data_len)
188 btrfs_extend_item(path, size - old_data_len);
189 else if (size < old_data_len)
190 btrfs_truncate_item(path, 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(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 if (!ret) {
217 set_bit(BTRFS_INODE_COPY_EVERYTHING,
218 &BTRFS_I(inode)->runtime_flags);
219 clear_bit(BTRFS_INODE_NO_XATTRS, &BTRFS_I(inode)->runtime_flags);
220 }
221 return ret;
222}
223
224/*
225 * @value: "" makes the attribute to empty, NULL removes it
226 */
227int btrfs_setxattr_trans(struct inode *inode, const char *name,
228 const void *value, size_t size, int flags)
229{
230 struct btrfs_root *root = BTRFS_I(inode)->root;
231 struct btrfs_trans_handle *trans;
232 const bool start_trans = (current->journal_info == NULL);
233 int ret;
234
235 if (start_trans) {
236 /*
237 * 1 unit for inserting/updating/deleting the xattr
238 * 1 unit for the inode item update
239 */
240 trans = btrfs_start_transaction(root, 2);
241 if (IS_ERR(trans))
242 return PTR_ERR(trans);
243 } else {
244 /*
245 * This can happen when smack is enabled and a directory is being
246 * created. It happens through d_instantiate_new(), which calls
247 * smack_d_instantiate(), which in turn calls __vfs_setxattr() to
248 * set the transmute xattr (XATTR_NAME_SMACKTRANSMUTE) on the
249 * inode. We have already reserved space for the xattr and inode
250 * update at btrfs_mkdir(), so just use the transaction handle.
251 * We don't join or start a transaction, as that will reset the
252 * block_rsv of the handle and trigger a warning for the start
253 * case.
254 */
255 ASSERT(strncmp(name, XATTR_SECURITY_PREFIX,
256 XATTR_SECURITY_PREFIX_LEN) == 0);
257 trans = current->journal_info;
258 }
259
260 ret = btrfs_setxattr(trans, inode, name, value, size, flags);
261 if (ret)
262 goto out;
263
264 inode_inc_iversion(inode);
265 inode->i_ctime = current_time(inode);
266 ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
267 BUG_ON(ret);
268out:
269 if (start_trans)
270 btrfs_end_transaction(trans);
271 return ret;
272}
273
274ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
275{
276 struct btrfs_key key;
277 struct inode *inode = d_inode(dentry);
278 struct btrfs_root *root = BTRFS_I(inode)->root;
279 struct btrfs_path *path;
280 int ret = 0;
281 size_t total_size = 0, size_left = size;
282
283 /*
284 * ok we want all objects associated with this id.
285 * NOTE: we set key.offset = 0; because we want to start with the
286 * first xattr that we find and walk forward
287 */
288 key.objectid = btrfs_ino(BTRFS_I(inode));
289 key.type = BTRFS_XATTR_ITEM_KEY;
290 key.offset = 0;
291
292 path = btrfs_alloc_path();
293 if (!path)
294 return -ENOMEM;
295 path->reada = READA_FORWARD;
296
297 /* search for our xattrs */
298 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
299 if (ret < 0)
300 goto err;
301
302 while (1) {
303 struct extent_buffer *leaf;
304 int slot;
305 struct btrfs_dir_item *di;
306 struct btrfs_key found_key;
307 u32 item_size;
308 u32 cur;
309
310 leaf = path->nodes[0];
311 slot = path->slots[0];
312
313 /* this is where we start walking through the path */
314 if (slot >= btrfs_header_nritems(leaf)) {
315 /*
316 * if we've reached the last slot in this leaf we need
317 * to go to the next leaf and reset everything
318 */
319 ret = btrfs_next_leaf(root, path);
320 if (ret < 0)
321 goto err;
322 else if (ret > 0)
323 break;
324 continue;
325 }
326
327 btrfs_item_key_to_cpu(leaf, &found_key, slot);
328
329 /* check to make sure this item is what we want */
330 if (found_key.objectid != key.objectid)
331 break;
332 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
333 break;
334 if (found_key.type < BTRFS_XATTR_ITEM_KEY)
335 goto next_item;
336
337 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
338 item_size = btrfs_item_size_nr(leaf, slot);
339 cur = 0;
340 while (cur < item_size) {
341 u16 name_len = btrfs_dir_name_len(leaf, di);
342 u16 data_len = btrfs_dir_data_len(leaf, di);
343 u32 this_len = sizeof(*di) + name_len + data_len;
344 unsigned long name_ptr = (unsigned long)(di + 1);
345
346 total_size += name_len + 1;
347 /*
348 * We are just looking for how big our buffer needs to
349 * be.
350 */
351 if (!size)
352 goto next;
353
354 if (!buffer || (name_len + 1) > size_left) {
355 ret = -ERANGE;
356 goto err;
357 }
358
359 read_extent_buffer(leaf, buffer, name_ptr, name_len);
360 buffer[name_len] = '\0';
361
362 size_left -= name_len + 1;
363 buffer += name_len + 1;
364next:
365 cur += this_len;
366 di = (struct btrfs_dir_item *)((char *)di + this_len);
367 }
368next_item:
369 path->slots[0]++;
370 }
371 ret = total_size;
372
373err:
374 btrfs_free_path(path);
375
376 return ret;
377}
378
379static int btrfs_xattr_handler_get(const struct xattr_handler *handler,
380 struct dentry *unused, struct inode *inode,
381 const char *name, void *buffer, size_t size)
382{
383 name = xattr_full_name(handler, name);
384 return btrfs_getxattr(inode, name, buffer, size);
385}
386
387static int btrfs_xattr_handler_set(const struct xattr_handler *handler,
388 struct user_namespace *mnt_userns,
389 struct dentry *unused, struct inode *inode,
390 const char *name, const void *buffer,
391 size_t size, int flags)
392{
393 name = xattr_full_name(handler, name);
394 return btrfs_setxattr_trans(inode, name, buffer, size, flags);
395}
396
397static int btrfs_xattr_handler_set_prop(const struct xattr_handler *handler,
398 struct user_namespace *mnt_userns,
399 struct dentry *unused, struct inode *inode,
400 const char *name, const void *value,
401 size_t size, int flags)
402{
403 int ret;
404 struct btrfs_trans_handle *trans;
405 struct btrfs_root *root = BTRFS_I(inode)->root;
406
407 name = xattr_full_name(handler, name);
408 ret = btrfs_validate_prop(name, value, size);
409 if (ret)
410 return ret;
411
412 trans = btrfs_start_transaction(root, 2);
413 if (IS_ERR(trans))
414 return PTR_ERR(trans);
415
416 ret = btrfs_set_prop(trans, inode, name, value, size, flags);
417 if (!ret) {
418 inode_inc_iversion(inode);
419 inode->i_ctime = current_time(inode);
420 ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
421 BUG_ON(ret);
422 }
423
424 btrfs_end_transaction(trans);
425
426 return ret;
427}
428
429static const struct xattr_handler btrfs_security_xattr_handler = {
430 .prefix = XATTR_SECURITY_PREFIX,
431 .get = btrfs_xattr_handler_get,
432 .set = btrfs_xattr_handler_set,
433};
434
435static const struct xattr_handler btrfs_trusted_xattr_handler = {
436 .prefix = XATTR_TRUSTED_PREFIX,
437 .get = btrfs_xattr_handler_get,
438 .set = btrfs_xattr_handler_set,
439};
440
441static const struct xattr_handler btrfs_user_xattr_handler = {
442 .prefix = XATTR_USER_PREFIX,
443 .get = btrfs_xattr_handler_get,
444 .set = btrfs_xattr_handler_set,
445};
446
447static const struct xattr_handler btrfs_btrfs_xattr_handler = {
448 .prefix = XATTR_BTRFS_PREFIX,
449 .get = btrfs_xattr_handler_get,
450 .set = btrfs_xattr_handler_set_prop,
451};
452
453const struct xattr_handler *btrfs_xattr_handlers[] = {
454 &btrfs_security_xattr_handler,
455#ifdef CONFIG_BTRFS_FS_POSIX_ACL
456 &posix_acl_access_xattr_handler,
457 &posix_acl_default_xattr_handler,
458#endif
459 &btrfs_trusted_xattr_handler,
460 &btrfs_user_xattr_handler,
461 &btrfs_btrfs_xattr_handler,
462 NULL,
463};
464
465static int btrfs_initxattrs(struct inode *inode,
466 const struct xattr *xattr_array, void *fs_private)
467{
468 struct btrfs_trans_handle *trans = fs_private;
469 const struct xattr *xattr;
470 unsigned int nofs_flag;
471 char *name;
472 int err = 0;
473
474 /*
475 * We're holding a transaction handle, so use a NOFS memory allocation
476 * context to avoid deadlock if reclaim happens.
477 */
478 nofs_flag = memalloc_nofs_save();
479 for (xattr = xattr_array; xattr->name != NULL; xattr++) {
480 name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
481 strlen(xattr->name) + 1, GFP_KERNEL);
482 if (!name) {
483 err = -ENOMEM;
484 break;
485 }
486 strcpy(name, XATTR_SECURITY_PREFIX);
487 strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
488 err = btrfs_setxattr(trans, inode, name, xattr->value,
489 xattr->value_len, 0);
490 kfree(name);
491 if (err < 0)
492 break;
493 }
494 memalloc_nofs_restore(nofs_flag);
495 return err;
496}
497
498int btrfs_xattr_security_init(struct btrfs_trans_handle *trans,
499 struct inode *inode, struct inode *dir,
500 const struct qstr *qstr)
501{
502 return security_inode_init_security(inode, dir, qstr,
503 &btrfs_initxattrs, trans);
504}