2 * Copyright (C) 2007 Red Hat. All rights reserved.
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.
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.
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.
19 #include <linux/init.h>
21 #include <linux/slab.h>
22 #include <linux/rwsem.h>
23 #include <linux/xattr.h>
24 #include <linux/security.h>
26 #include "btrfs_inode.h"
27 #include "transaction.h"
32 ssize_t __btrfs_getxattr(struct inode *inode, const char *name,
33 void *buffer, size_t size)
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;
40 unsigned long data_ptr;
42 path = btrfs_alloc_path();
46 /* lookup the xattr by name */
47 di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(inode), name,
52 } else if (IS_ERR(di)) {
57 leaf = path->nodes[0];
58 /* if size is 0, that means we want the size of the attr */
60 ret = btrfs_dir_data_len(leaf, di);
64 /* now get the data out of our dir_item */
65 if (btrfs_dir_data_len(leaf, di) > size) {
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
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);
84 btrfs_free_path(path);
88 static int do_setxattr(struct btrfs_trans_handle *trans,
89 struct inode *inode, const char *name,
90 const void *value, size_t size, int flags)
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);
98 if (name_len + size > BTRFS_MAX_XATTR_SIZE(root))
101 path = btrfs_alloc_path();
105 if (flags & XATTR_REPLACE) {
106 di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(inode), name,
115 ret = btrfs_delete_one_dir_name(trans, root, path, di);
118 btrfs_release_path(path);
121 * remove the attribute
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)
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.
138 btrfs_release_path(path);
139 di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(inode),
145 /* Shouldn't happen but just in case... */
146 btrfs_release_path(path);
150 ret = btrfs_delete_one_dir_name(trans, root, path, di);
155 * We have a value to set, so go back and try to insert it now.
158 btrfs_release_path(path);
163 btrfs_free_path(path);
168 * @value: "" makes the attribute to empty, NULL removes it
170 int __btrfs_setxattr(struct btrfs_trans_handle *trans,
171 struct inode *inode, const char *name,
172 const void *value, size_t size, int flags)
174 struct btrfs_root *root = BTRFS_I(inode)->root;
178 return do_setxattr(trans, inode, name, value, size, flags);
180 trans = btrfs_start_transaction(root, 2);
182 return PTR_ERR(trans);
184 ret = do_setxattr(trans, inode, name, value, size, flags);
188 inode->i_ctime = CURRENT_TIME;
189 ret = btrfs_update_inode(trans, root, inode);
192 btrfs_end_transaction_throttle(trans, root);
196 ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
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;
205 size_t total_size = 0, size_left = size;
206 unsigned long name_ptr;
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
214 key.objectid = btrfs_ino(inode);
215 btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
218 path = btrfs_alloc_path();
223 /* search for our xattrs */
224 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
229 leaf = path->nodes[0];
230 slot = path->slots[0];
232 /* this is where we start walking through the path */
233 if (slot >= btrfs_header_nritems(leaf)) {
235 * if we've reached the last slot in this leaf we need
236 * to go to the next leaf and reset everything
238 ret = btrfs_next_leaf(root, path);
246 btrfs_item_key_to_cpu(leaf, &found_key, slot);
248 /* check to make sure this item is what we want */
249 if (found_key.objectid != key.objectid)
251 if (btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY)
254 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
255 if (verify_dir_item(root, leaf, di))
258 name_len = btrfs_dir_name_len(leaf, di);
259 total_size += name_len + 1;
261 /* we are just looking for how big our buffer needs to be */
265 if (!buffer || (name_len + 1) > size_left) {
270 name_ptr = (unsigned long)(di + 1);
271 read_extent_buffer(leaf, buffer, name_ptr, name_len);
272 buffer[name_len] = '\0';
274 size_left -= name_len + 1;
275 buffer += name_len + 1;
282 btrfs_free_path(path);
288 * List of handlers for synthetic system.* attributes. All real ondisk
289 * attributes are handled directly.
291 const 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,
300 * Check if the attribute is in a supported namespace.
302 * This applied after the check for the synthetic attributes in the system
305 static bool btrfs_is_valid_xattr(const char *name)
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);
314 ssize_t btrfs_getxattr(struct dentry *dentry, const char *name,
315 void *buffer, size_t size)
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.
322 if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
323 return generic_getxattr(dentry, name, buffer, size);
325 if (!btrfs_is_valid_xattr(name))
327 return __btrfs_getxattr(dentry->d_inode, name, buffer, size);
330 int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value,
331 size_t size, int flags)
333 struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root;
336 * The permission on security.* and system.* is not checked
339 if (btrfs_root_readonly(root))
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.
347 if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
348 return generic_setxattr(dentry, name, value, size, flags);
350 if (!btrfs_is_valid_xattr(name))
354 value = ""; /* empty EA, do not remove */
356 return __btrfs_setxattr(NULL, dentry->d_inode, name, value, size,
360 int btrfs_removexattr(struct dentry *dentry, const char *name)
362 struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root;
365 * The permission on security.* and system.* is not checked
368 if (btrfs_root_readonly(root))
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.
376 if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
377 return generic_removexattr(dentry, name);
379 if (!btrfs_is_valid_xattr(name))
382 return __btrfs_setxattr(NULL, dentry->d_inode, name, NULL, 0,
386 int btrfs_initxattrs(struct inode *inode, const struct xattr *xattr_array,
389 const struct xattr *xattr;
390 struct btrfs_trans_handle *trans = fs_info;
394 for (xattr = xattr_array; xattr->name != NULL; xattr++) {
395 name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
396 strlen(xattr->name) + 1, GFP_NOFS);
401 strcpy(name, XATTR_SECURITY_PREFIX);
402 strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
403 err = __btrfs_setxattr(trans, inode, name,
404 xattr->value, xattr->value_len, 0);
412 int btrfs_xattr_security_init(struct btrfs_trans_handle *trans,
413 struct inode *inode, struct inode *dir,
414 const struct qstr *qstr)
416 return security_inode_init_security(inode, dir, qstr,
417 &btrfs_initxattrs, trans);