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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// 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 return ret;
220}
221
222/*
223 * @value: "" makes the attribute to empty, NULL removes it
224 */
225int btrfs_setxattr_trans(struct inode *inode, const char *name,
226 const void *value, size_t size, int flags)
227{
228 struct btrfs_root *root = BTRFS_I(inode)->root;
229 struct btrfs_trans_handle *trans;
230 int ret;
231
232 trans = btrfs_start_transaction(root, 2);
233 if (IS_ERR(trans))
234 return PTR_ERR(trans);
235
236 ret = btrfs_setxattr(trans, inode, name, value, size, flags);
237 if (ret)
238 goto out;
239
240 inode_inc_iversion(inode);
241 inode->i_ctime = current_time(inode);
242 ret = btrfs_update_inode(trans, root, inode);
243 BUG_ON(ret);
244out:
245 btrfs_end_transaction(trans);
246 return ret;
247}
248
249ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
250{
251 struct btrfs_key key;
252 struct inode *inode = d_inode(dentry);
253 struct btrfs_root *root = BTRFS_I(inode)->root;
254 struct btrfs_path *path;
255 int ret = 0;
256 size_t total_size = 0, size_left = size;
257
258 /*
259 * ok we want all objects associated with this id.
260 * NOTE: we set key.offset = 0; because we want to start with the
261 * first xattr that we find and walk forward
262 */
263 key.objectid = btrfs_ino(BTRFS_I(inode));
264 key.type = BTRFS_XATTR_ITEM_KEY;
265 key.offset = 0;
266
267 path = btrfs_alloc_path();
268 if (!path)
269 return -ENOMEM;
270 path->reada = READA_FORWARD;
271
272 /* search for our xattrs */
273 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
274 if (ret < 0)
275 goto err;
276
277 while (1) {
278 struct extent_buffer *leaf;
279 int slot;
280 struct btrfs_dir_item *di;
281 struct btrfs_key found_key;
282 u32 item_size;
283 u32 cur;
284
285 leaf = path->nodes[0];
286 slot = path->slots[0];
287
288 /* this is where we start walking through the path */
289 if (slot >= btrfs_header_nritems(leaf)) {
290 /*
291 * if we've reached the last slot in this leaf we need
292 * to go to the next leaf and reset everything
293 */
294 ret = btrfs_next_leaf(root, path);
295 if (ret < 0)
296 goto err;
297 else if (ret > 0)
298 break;
299 continue;
300 }
301
302 btrfs_item_key_to_cpu(leaf, &found_key, slot);
303
304 /* check to make sure this item is what we want */
305 if (found_key.objectid != key.objectid)
306 break;
307 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
308 break;
309 if (found_key.type < BTRFS_XATTR_ITEM_KEY)
310 goto next_item;
311
312 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
313 item_size = btrfs_item_size_nr(leaf, slot);
314 cur = 0;
315 while (cur < item_size) {
316 u16 name_len = btrfs_dir_name_len(leaf, di);
317 u16 data_len = btrfs_dir_data_len(leaf, di);
318 u32 this_len = sizeof(*di) + name_len + data_len;
319 unsigned long name_ptr = (unsigned long)(di + 1);
320
321 total_size += name_len + 1;
322 /*
323 * We are just looking for how big our buffer needs to
324 * be.
325 */
326 if (!size)
327 goto next;
328
329 if (!buffer || (name_len + 1) > size_left) {
330 ret = -ERANGE;
331 goto err;
332 }
333
334 read_extent_buffer(leaf, buffer, name_ptr, name_len);
335 buffer[name_len] = '\0';
336
337 size_left -= name_len + 1;
338 buffer += name_len + 1;
339next:
340 cur += this_len;
341 di = (struct btrfs_dir_item *)((char *)di + this_len);
342 }
343next_item:
344 path->slots[0]++;
345 }
346 ret = total_size;
347
348err:
349 btrfs_free_path(path);
350
351 return ret;
352}
353
354static int btrfs_xattr_handler_get(const struct xattr_handler *handler,
355 struct dentry *unused, struct inode *inode,
356 const char *name, void *buffer, size_t size)
357{
358 name = xattr_full_name(handler, name);
359 return btrfs_getxattr(inode, name, buffer, size);
360}
361
362static int btrfs_xattr_handler_set(const struct xattr_handler *handler,
363 struct dentry *unused, struct inode *inode,
364 const char *name, const void *buffer,
365 size_t size, int flags)
366{
367 name = xattr_full_name(handler, name);
368 return btrfs_setxattr_trans(inode, name, buffer, size, flags);
369}
370
371static int btrfs_xattr_handler_set_prop(const struct xattr_handler *handler,
372 struct dentry *unused, struct inode *inode,
373 const char *name, const void *value,
374 size_t size, int flags)
375{
376 int ret;
377 struct btrfs_trans_handle *trans;
378 struct btrfs_root *root = BTRFS_I(inode)->root;
379
380 name = xattr_full_name(handler, name);
381 ret = btrfs_validate_prop(name, value, size);
382 if (ret)
383 return ret;
384
385 trans = btrfs_start_transaction(root, 2);
386 if (IS_ERR(trans))
387 return PTR_ERR(trans);
388
389 ret = btrfs_set_prop(trans, inode, name, value, size, flags);
390 if (!ret) {
391 inode_inc_iversion(inode);
392 inode->i_ctime = current_time(inode);
393 ret = btrfs_update_inode(trans, root, inode);
394 BUG_ON(ret);
395 }
396
397 btrfs_end_transaction(trans);
398
399 return ret;
400}
401
402static const struct xattr_handler btrfs_security_xattr_handler = {
403 .prefix = XATTR_SECURITY_PREFIX,
404 .get = btrfs_xattr_handler_get,
405 .set = btrfs_xattr_handler_set,
406};
407
408static const struct xattr_handler btrfs_trusted_xattr_handler = {
409 .prefix = XATTR_TRUSTED_PREFIX,
410 .get = btrfs_xattr_handler_get,
411 .set = btrfs_xattr_handler_set,
412};
413
414static const struct xattr_handler btrfs_user_xattr_handler = {
415 .prefix = XATTR_USER_PREFIX,
416 .get = btrfs_xattr_handler_get,
417 .set = btrfs_xattr_handler_set,
418};
419
420static const struct xattr_handler btrfs_btrfs_xattr_handler = {
421 .prefix = XATTR_BTRFS_PREFIX,
422 .get = btrfs_xattr_handler_get,
423 .set = btrfs_xattr_handler_set_prop,
424};
425
426const struct xattr_handler *btrfs_xattr_handlers[] = {
427 &btrfs_security_xattr_handler,
428#ifdef CONFIG_BTRFS_FS_POSIX_ACL
429 &posix_acl_access_xattr_handler,
430 &posix_acl_default_xattr_handler,
431#endif
432 &btrfs_trusted_xattr_handler,
433 &btrfs_user_xattr_handler,
434 &btrfs_btrfs_xattr_handler,
435 NULL,
436};
437
438static int btrfs_initxattrs(struct inode *inode,
439 const struct xattr *xattr_array, void *fs_private)
440{
441 struct btrfs_trans_handle *trans = fs_private;
442 const struct xattr *xattr;
443 unsigned int nofs_flag;
444 char *name;
445 int err = 0;
446
447 /*
448 * We're holding a transaction handle, so use a NOFS memory allocation
449 * context to avoid deadlock if reclaim happens.
450 */
451 nofs_flag = memalloc_nofs_save();
452 for (xattr = xattr_array; xattr->name != NULL; xattr++) {
453 name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
454 strlen(xattr->name) + 1, GFP_KERNEL);
455 if (!name) {
456 err = -ENOMEM;
457 break;
458 }
459 strcpy(name, XATTR_SECURITY_PREFIX);
460 strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
461 err = btrfs_setxattr(trans, inode, name, xattr->value,
462 xattr->value_len, 0);
463 kfree(name);
464 if (err < 0)
465 break;
466 }
467 memalloc_nofs_restore(nofs_flag);
468 return err;
469}
470
471int btrfs_xattr_security_init(struct btrfs_trans_handle *trans,
472 struct inode *inode, struct inode *dir,
473 const struct qstr *qstr)
474{
475 return security_inode_init_security(inode, dir, qstr,
476 &btrfs_initxattrs, trans);
477}