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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 "fs.h"
17#include "messages.h"
18#include "btrfs_inode.h"
19#include "transaction.h"
20#include "xattr.h"
21#include "disk-io.h"
22#include "props.h"
23#include "locking.h"
24#include "accessors.h"
25#include "dir-item.h"
26
27int btrfs_getxattr(const struct inode *inode, const char *name,
28 void *buffer, size_t size)
29{
30 struct btrfs_dir_item *di;
31 struct btrfs_root *root = BTRFS_I(inode)->root;
32 struct btrfs_path *path;
33 struct extent_buffer *leaf;
34 int ret = 0;
35 unsigned long data_ptr;
36
37 path = btrfs_alloc_path();
38 if (!path)
39 return -ENOMEM;
40
41 /* lookup the xattr by name */
42 di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(BTRFS_I(inode)),
43 name, strlen(name), 0);
44 if (!di) {
45 ret = -ENODATA;
46 goto out;
47 } else if (IS_ERR(di)) {
48 ret = PTR_ERR(di);
49 goto out;
50 }
51
52 leaf = path->nodes[0];
53 /* if size is 0, that means we want the size of the attr */
54 if (!size) {
55 ret = btrfs_dir_data_len(leaf, di);
56 goto out;
57 }
58
59 /* now get the data out of our dir_item */
60 if (btrfs_dir_data_len(leaf, di) > size) {
61 ret = -ERANGE;
62 goto out;
63 }
64
65 /*
66 * The way things are packed into the leaf is like this
67 * |struct btrfs_dir_item|name|data|
68 * where name is the xattr name, so security.foo, and data is the
69 * content of the xattr. data_ptr points to the location in memory
70 * where the data starts in the in memory leaf
71 */
72 data_ptr = (unsigned long)((char *)(di + 1) +
73 btrfs_dir_name_len(leaf, di));
74 read_extent_buffer(leaf, buffer, data_ptr,
75 btrfs_dir_data_len(leaf, di));
76 ret = btrfs_dir_data_len(leaf, di);
77
78out:
79 btrfs_free_path(path);
80 return ret;
81}
82
83int btrfs_setxattr(struct btrfs_trans_handle *trans, struct inode *inode,
84 const char *name, const void *value, size_t size, int flags)
85{
86 struct btrfs_dir_item *di = NULL;
87 struct btrfs_root *root = BTRFS_I(inode)->root;
88 struct btrfs_path *path;
89 size_t name_len = strlen(name);
90 int ret = 0;
91
92 ASSERT(trans);
93
94 if (name_len + size > BTRFS_MAX_XATTR_SIZE(root->fs_info))
95 return -ENOSPC;
96
97 path = btrfs_alloc_path();
98 if (!path)
99 return -ENOMEM;
100 path->skip_release_on_error = 1;
101
102 if (!value) {
103 di = btrfs_lookup_xattr(trans, root, path,
104 btrfs_ino(BTRFS_I(inode)), name, name_len, -1);
105 if (!di && (flags & XATTR_REPLACE))
106 ret = -ENODATA;
107 else if (IS_ERR(di))
108 ret = PTR_ERR(di);
109 else if (di)
110 ret = btrfs_delete_one_dir_name(trans, root, path, di);
111 goto out;
112 }
113
114 /*
115 * For a replace we can't just do the insert blindly.
116 * Do a lookup first (read-only btrfs_search_slot), and return if xattr
117 * doesn't exist. If it exists, fall down below to the insert/replace
118 * path - we can't race with a concurrent xattr delete, because the VFS
119 * locks the inode's i_mutex before calling setxattr or removexattr.
120 */
121 if (flags & XATTR_REPLACE) {
122 btrfs_assert_inode_locked(BTRFS_I(inode));
123 di = btrfs_lookup_xattr(NULL, root, path,
124 btrfs_ino(BTRFS_I(inode)), name, name_len, 0);
125 if (!di)
126 ret = -ENODATA;
127 else if (IS_ERR(di))
128 ret = PTR_ERR(di);
129 if (ret)
130 goto out;
131 btrfs_release_path(path);
132 di = NULL;
133 }
134
135 ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(BTRFS_I(inode)),
136 name, name_len, value, size);
137 if (ret == -EOVERFLOW) {
138 /*
139 * We have an existing item in a leaf, split_leaf couldn't
140 * expand it. That item might have or not a dir_item that
141 * matches our target xattr, so lets check.
142 */
143 ret = 0;
144 btrfs_assert_tree_write_locked(path->nodes[0]);
145 di = btrfs_match_dir_item_name(path, name, name_len);
146 if (!di && !(flags & XATTR_REPLACE)) {
147 ret = -ENOSPC;
148 goto out;
149 }
150 } else if (ret == -EEXIST) {
151 ret = 0;
152 di = btrfs_match_dir_item_name(path, name, name_len);
153 ASSERT(di); /* logic error */
154 } else if (ret) {
155 goto out;
156 }
157
158 if (di && (flags & XATTR_CREATE)) {
159 ret = -EEXIST;
160 goto out;
161 }
162
163 if (di) {
164 /*
165 * We're doing a replace, and it must be atomic, that is, at
166 * any point in time we have either the old or the new xattr
167 * value in the tree. We don't want readers (getxattr and
168 * listxattrs) to miss a value, this is specially important
169 * for ACLs.
170 */
171 const int slot = path->slots[0];
172 struct extent_buffer *leaf = path->nodes[0];
173 const u16 old_data_len = btrfs_dir_data_len(leaf, di);
174 const u32 item_size = btrfs_item_size(leaf, slot);
175 const u32 data_size = sizeof(*di) + name_len + size;
176 unsigned long data_ptr;
177 char *ptr;
178
179 if (size > old_data_len) {
180 if (btrfs_leaf_free_space(leaf) <
181 (size - old_data_len)) {
182 ret = -ENOSPC;
183 goto out;
184 }
185 }
186
187 if (old_data_len + name_len + sizeof(*di) == item_size) {
188 /* No other xattrs packed in the same leaf item. */
189 if (size > old_data_len)
190 btrfs_extend_item(trans, path, size - old_data_len);
191 else if (size < old_data_len)
192 btrfs_truncate_item(trans, path, data_size, 1);
193 } else {
194 /* There are other xattrs packed in the same item. */
195 ret = btrfs_delete_one_dir_name(trans, root, path, di);
196 if (ret)
197 goto out;
198 btrfs_extend_item(trans, path, data_size);
199 }
200
201 ptr = btrfs_item_ptr(leaf, slot, char);
202 ptr += btrfs_item_size(leaf, slot) - data_size;
203 di = (struct btrfs_dir_item *)ptr;
204 btrfs_set_dir_data_len(leaf, di, size);
205 data_ptr = ((unsigned long)(di + 1)) + name_len;
206 write_extent_buffer(leaf, value, data_ptr, size);
207 btrfs_mark_buffer_dirty(trans, leaf);
208 } else {
209 /*
210 * Insert, and we had space for the xattr, so path->slots[0] is
211 * where our xattr dir_item is and btrfs_insert_xattr_item()
212 * filled it.
213 */
214 }
215out:
216 btrfs_free_path(path);
217 if (!ret) {
218 set_bit(BTRFS_INODE_COPY_EVERYTHING,
219 &BTRFS_I(inode)->runtime_flags);
220 clear_bit(BTRFS_INODE_NO_XATTRS, &BTRFS_I(inode)->runtime_flags);
221 }
222 return ret;
223}
224
225/*
226 * @value: "" makes the attribute to empty, NULL removes it
227 */
228int btrfs_setxattr_trans(struct inode *inode, const char *name,
229 const void *value, size_t size, int flags)
230{
231 struct btrfs_root *root = BTRFS_I(inode)->root;
232 struct btrfs_trans_handle *trans;
233 const bool start_trans = (current->journal_info == NULL);
234 int ret;
235
236 if (start_trans) {
237 /*
238 * 1 unit for inserting/updating/deleting the xattr
239 * 1 unit for the inode item update
240 */
241 trans = btrfs_start_transaction(root, 2);
242 if (IS_ERR(trans))
243 return PTR_ERR(trans);
244 } else {
245 /*
246 * This can happen when smack is enabled and a directory is being
247 * created. It happens through d_instantiate_new(), which calls
248 * smack_d_instantiate(), which in turn calls __vfs_setxattr() to
249 * set the transmute xattr (XATTR_NAME_SMACKTRANSMUTE) on the
250 * inode. We have already reserved space for the xattr and inode
251 * update at btrfs_mkdir(), so just use the transaction handle.
252 * We don't join or start a transaction, as that will reset the
253 * block_rsv of the handle and trigger a warning for the start
254 * case.
255 */
256 ASSERT(strncmp(name, XATTR_SECURITY_PREFIX,
257 XATTR_SECURITY_PREFIX_LEN) == 0);
258 trans = current->journal_info;
259 }
260
261 ret = btrfs_setxattr(trans, inode, name, value, size, flags);
262 if (ret)
263 goto out;
264
265 inode_inc_iversion(inode);
266 inode_set_ctime_current(inode);
267 ret = btrfs_update_inode(trans, BTRFS_I(inode));
268 if (ret)
269 btrfs_abort_transaction(trans, ret);
270out:
271 if (start_trans)
272 btrfs_end_transaction(trans);
273 return ret;
274}
275
276ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
277{
278 struct btrfs_key found_key;
279 struct btrfs_key key;
280 struct inode *inode = d_inode(dentry);
281 struct btrfs_root *root = BTRFS_I(inode)->root;
282 struct btrfs_path *path;
283 int iter_ret = 0;
284 int ret = 0;
285 size_t total_size = 0, size_left = size;
286
287 /*
288 * ok we want all objects associated with this id.
289 * NOTE: we set key.offset = 0; because we want to start with the
290 * first xattr that we find and walk forward
291 */
292 key.objectid = btrfs_ino(BTRFS_I(inode));
293 key.type = BTRFS_XATTR_ITEM_KEY;
294 key.offset = 0;
295
296 path = btrfs_alloc_path();
297 if (!path)
298 return -ENOMEM;
299 path->reada = READA_FORWARD;
300
301 /* search for our xattrs */
302 btrfs_for_each_slot(root, &key, &found_key, path, iter_ret) {
303 struct extent_buffer *leaf;
304 int slot;
305 struct btrfs_dir_item *di;
306 u32 item_size;
307 u32 cur;
308
309 leaf = path->nodes[0];
310 slot = path->slots[0];
311
312 /* check to make sure this item is what we want */
313 if (found_key.objectid != key.objectid)
314 break;
315 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
316 break;
317 if (found_key.type < BTRFS_XATTR_ITEM_KEY)
318 continue;
319
320 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
321 item_size = btrfs_item_size(leaf, slot);
322 cur = 0;
323 while (cur < item_size) {
324 u16 name_len = btrfs_dir_name_len(leaf, di);
325 u16 data_len = btrfs_dir_data_len(leaf, di);
326 u32 this_len = sizeof(*di) + name_len + data_len;
327 unsigned long name_ptr = (unsigned long)(di + 1);
328
329 total_size += name_len + 1;
330 /*
331 * We are just looking for how big our buffer needs to
332 * be.
333 */
334 if (!size)
335 goto next;
336
337 if (!buffer || (name_len + 1) > size_left) {
338 iter_ret = -ERANGE;
339 break;
340 }
341
342 read_extent_buffer(leaf, buffer, name_ptr, name_len);
343 buffer[name_len] = '\0';
344
345 size_left -= name_len + 1;
346 buffer += name_len + 1;
347next:
348 cur += this_len;
349 di = (struct btrfs_dir_item *)((char *)di + this_len);
350 }
351 }
352
353 if (iter_ret < 0)
354 ret = iter_ret;
355 else
356 ret = total_size;
357
358 btrfs_free_path(path);
359
360 return ret;
361}
362
363static int btrfs_xattr_handler_get(const struct xattr_handler *handler,
364 struct dentry *unused, struct inode *inode,
365 const char *name, void *buffer, size_t size)
366{
367 name = xattr_full_name(handler, name);
368 return btrfs_getxattr(inode, name, buffer, size);
369}
370
371static int btrfs_xattr_handler_set(const struct xattr_handler *handler,
372 struct mnt_idmap *idmap,
373 struct dentry *unused, struct inode *inode,
374 const char *name, const void *buffer,
375 size_t size, int flags)
376{
377 if (btrfs_root_readonly(BTRFS_I(inode)->root))
378 return -EROFS;
379
380 name = xattr_full_name(handler, name);
381 return btrfs_setxattr_trans(inode, name, buffer, size, flags);
382}
383
384static int btrfs_xattr_handler_get_security(const struct xattr_handler *handler,
385 struct dentry *unused,
386 struct inode *inode,
387 const char *name, void *buffer,
388 size_t size)
389{
390 int ret;
391 bool is_cap = false;
392
393 name = xattr_full_name(handler, name);
394
395 /*
396 * security.capability doesn't cache the results, so calls into us
397 * constantly to see if there's a capability xattr. Cache the result
398 * here in order to avoid wasting time doing lookups for xattrs we know
399 * don't exist.
400 */
401 if (strcmp(name, XATTR_NAME_CAPS) == 0) {
402 is_cap = true;
403 if (test_bit(BTRFS_INODE_NO_CAP_XATTR, &BTRFS_I(inode)->runtime_flags))
404 return -ENODATA;
405 }
406
407 ret = btrfs_getxattr(inode, name, buffer, size);
408 if (ret == -ENODATA && is_cap)
409 set_bit(BTRFS_INODE_NO_CAP_XATTR, &BTRFS_I(inode)->runtime_flags);
410 return ret;
411}
412
413static int btrfs_xattr_handler_set_security(const struct xattr_handler *handler,
414 struct mnt_idmap *idmap,
415 struct dentry *unused,
416 struct inode *inode,
417 const char *name,
418 const void *buffer,
419 size_t size, int flags)
420{
421 if (btrfs_root_readonly(BTRFS_I(inode)->root))
422 return -EROFS;
423
424 name = xattr_full_name(handler, name);
425 if (strcmp(name, XATTR_NAME_CAPS) == 0)
426 clear_bit(BTRFS_INODE_NO_CAP_XATTR, &BTRFS_I(inode)->runtime_flags);
427
428 return btrfs_setxattr_trans(inode, name, buffer, size, flags);
429}
430
431static int btrfs_xattr_handler_set_prop(const struct xattr_handler *handler,
432 struct mnt_idmap *idmap,
433 struct dentry *unused, struct inode *inode,
434 const char *name, const void *value,
435 size_t size, int flags)
436{
437 int ret;
438 struct btrfs_trans_handle *trans;
439 struct btrfs_root *root = BTRFS_I(inode)->root;
440
441 name = xattr_full_name(handler, name);
442 ret = btrfs_validate_prop(BTRFS_I(inode), name, value, size);
443 if (ret)
444 return ret;
445
446 if (btrfs_ignore_prop(BTRFS_I(inode), name))
447 return 0;
448
449 trans = btrfs_start_transaction(root, 2);
450 if (IS_ERR(trans))
451 return PTR_ERR(trans);
452
453 ret = btrfs_set_prop(trans, BTRFS_I(inode), name, value, size, flags);
454 if (!ret) {
455 inode_inc_iversion(inode);
456 inode_set_ctime_current(inode);
457 ret = btrfs_update_inode(trans, BTRFS_I(inode));
458 if (ret)
459 btrfs_abort_transaction(trans, ret);
460 }
461
462 btrfs_end_transaction(trans);
463
464 return ret;
465}
466
467static const struct xattr_handler btrfs_security_xattr_handler = {
468 .prefix = XATTR_SECURITY_PREFIX,
469 .get = btrfs_xattr_handler_get_security,
470 .set = btrfs_xattr_handler_set_security,
471};
472
473static const struct xattr_handler btrfs_trusted_xattr_handler = {
474 .prefix = XATTR_TRUSTED_PREFIX,
475 .get = btrfs_xattr_handler_get,
476 .set = btrfs_xattr_handler_set,
477};
478
479static const struct xattr_handler btrfs_user_xattr_handler = {
480 .prefix = XATTR_USER_PREFIX,
481 .get = btrfs_xattr_handler_get,
482 .set = btrfs_xattr_handler_set,
483};
484
485static const struct xattr_handler btrfs_btrfs_xattr_handler = {
486 .prefix = XATTR_BTRFS_PREFIX,
487 .get = btrfs_xattr_handler_get,
488 .set = btrfs_xattr_handler_set_prop,
489};
490
491const struct xattr_handler * const btrfs_xattr_handlers[] = {
492 &btrfs_security_xattr_handler,
493 &btrfs_trusted_xattr_handler,
494 &btrfs_user_xattr_handler,
495 &btrfs_btrfs_xattr_handler,
496 NULL,
497};
498
499static int btrfs_initxattrs(struct inode *inode,
500 const struct xattr *xattr_array, void *fs_private)
501{
502 struct btrfs_trans_handle *trans = fs_private;
503 const struct xattr *xattr;
504 unsigned int nofs_flag;
505 char *name;
506 int ret = 0;
507
508 /*
509 * We're holding a transaction handle, so use a NOFS memory allocation
510 * context to avoid deadlock if reclaim happens.
511 */
512 nofs_flag = memalloc_nofs_save();
513 for (xattr = xattr_array; xattr->name != NULL; xattr++) {
514 name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
515 strlen(xattr->name) + 1, GFP_KERNEL);
516 if (!name) {
517 ret = -ENOMEM;
518 break;
519 }
520 strcpy(name, XATTR_SECURITY_PREFIX);
521 strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
522
523 if (strcmp(name, XATTR_NAME_CAPS) == 0)
524 clear_bit(BTRFS_INODE_NO_CAP_XATTR, &BTRFS_I(inode)->runtime_flags);
525
526 ret = btrfs_setxattr(trans, inode, name, xattr->value,
527 xattr->value_len, 0);
528 kfree(name);
529 if (ret < 0)
530 break;
531 }
532 memalloc_nofs_restore(nofs_flag);
533 return ret;
534}
535
536int btrfs_xattr_security_init(struct btrfs_trans_handle *trans,
537 struct inode *inode, struct inode *dir,
538 const struct qstr *qstr)
539{
540 return security_inode_init_security(inode, dir, qstr,
541 &btrfs_initxattrs, trans);
542}