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c1d7c514 | 1 | // SPDX-License-Identifier: GPL-2.0 |
5103e947 JB |
2 | /* |
3 | * Copyright (C) 2007 Red Hat. All rights reserved. | |
5103e947 JB |
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> | |
0279b4cd | 11 | #include <linux/security.h> |
996a710d | 12 | #include <linux/posix_acl_xattr.h> |
ae5e165d | 13 | #include <linux/iversion.h> |
5103e947 JB |
14 | #include "ctree.h" |
15 | #include "btrfs_inode.h" | |
16 | #include "transaction.h" | |
17 | #include "xattr.h" | |
18 | #include "disk-io.h" | |
63541927 | 19 | #include "props.h" |
5f5bc6b1 | 20 | #include "locking.h" |
33268eaf | 21 | |
bcadd705 | 22 | int btrfs_getxattr(struct inode *inode, const char *name, |
95819c05 | 23 | void *buffer, size_t size) |
5103e947 JB |
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; | |
5103e947 JB |
29 | int ret = 0; |
30 | unsigned long data_ptr; | |
5103e947 JB |
31 | |
32 | path = btrfs_alloc_path(); | |
95819c05 | 33 | if (!path) |
5103e947 | 34 | return -ENOMEM; |
5103e947 | 35 | |
5103e947 | 36 | /* lookup the xattr by name */ |
f85b7379 DS |
37 | di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(BTRFS_I(inode)), |
38 | name, strlen(name), 0); | |
07060404 | 39 | if (!di) { |
5103e947 JB |
40 | ret = -ENODATA; |
41 | goto out; | |
07060404 JB |
42 | } else if (IS_ERR(di)) { |
43 | ret = PTR_ERR(di); | |
44 | goto out; | |
5103e947 JB |
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 | } | |
07060404 JB |
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 | */ | |
5103e947 JB |
67 | data_ptr = (unsigned long)((char *)(di + 1) + |
68 | btrfs_dir_name_len(leaf, di)); | |
69 | read_extent_buffer(leaf, buffer, data_ptr, | |
3acd7ee8 | 70 | btrfs_dir_data_len(leaf, di)); |
5103e947 JB |
71 | ret = btrfs_dir_data_len(leaf, di); |
72 | ||
73 | out: | |
5103e947 JB |
74 | btrfs_free_path(path); |
75 | return ret; | |
76 | } | |
77 | ||
f34f57a3 YZ |
78 | static int do_setxattr(struct btrfs_trans_handle *trans, |
79 | struct inode *inode, const char *name, | |
80 | const void *value, size_t size, int flags) | |
5103e947 | 81 | { |
5f5bc6b1 | 82 | struct btrfs_dir_item *di = NULL; |
5103e947 | 83 | struct btrfs_root *root = BTRFS_I(inode)->root; |
2ff7e61e | 84 | struct btrfs_fs_info *fs_info = root->fs_info; |
5103e947 | 85 | struct btrfs_path *path; |
f34f57a3 YZ |
86 | size_t name_len = strlen(name); |
87 | int ret = 0; | |
88 | ||
da17066c | 89 | if (name_len + size > BTRFS_MAX_XATTR_SIZE(root->fs_info)) |
f34f57a3 | 90 | return -ENOSPC; |
5103e947 JB |
91 | |
92 | path = btrfs_alloc_path(); | |
95819c05 | 93 | if (!path) |
5103e947 | 94 | return -ENOMEM; |
5f5bc6b1 FM |
95 | path->skip_release_on_error = 1; |
96 | ||
97 | if (!value) { | |
f85b7379 DS |
98 | di = btrfs_lookup_xattr(trans, root, path, |
99 | btrfs_ino(BTRFS_I(inode)), name, name_len, -1); | |
5f5bc6b1 FM |
100 | if (!di && (flags & XATTR_REPLACE)) |
101 | ret = -ENODATA; | |
5cdf83ed FM |
102 | else if (IS_ERR(di)) |
103 | ret = PTR_ERR(di); | |
5f5bc6b1 FM |
104 | else if (di) |
105 | ret = btrfs_delete_one_dir_name(trans, root, path, di); | |
106 | goto out; | |
107 | } | |
5103e947 | 108 | |
5f5bc6b1 FM |
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 | */ | |
fa09200b | 116 | if (flags & XATTR_REPLACE) { |
5955102c | 117 | ASSERT(inode_is_locked(inode)); |
f85b7379 DS |
118 | di = btrfs_lookup_xattr(NULL, root, path, |
119 | btrfs_ino(BTRFS_I(inode)), name, name_len, 0); | |
5cdf83ed | 120 | if (!di) |
fa09200b | 121 | ret = -ENODATA; |
5cdf83ed FM |
122 | else if (IS_ERR(di)) |
123 | ret = PTR_ERR(di); | |
124 | if (ret) | |
5103e947 | 125 | goto out; |
b3b4aa74 | 126 | btrfs_release_path(path); |
5f5bc6b1 FM |
127 | di = NULL; |
128 | } | |
4815053a | 129 | |
4a0cc7ca | 130 | ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(BTRFS_I(inode)), |
5f5bc6b1 FM |
131 | name, name_len, value, size); |
132 | if (ret == -EOVERFLOW) { | |
4815053a | 133 | /* |
5f5bc6b1 FM |
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. | |
4815053a | 137 | */ |
5f5bc6b1 FM |
138 | ret = 0; |
139 | btrfs_assert_tree_locked(path->nodes[0]); | |
2ff7e61e | 140 | di = btrfs_match_dir_item_name(fs_info, path, name, name_len); |
5f5bc6b1 FM |
141 | if (!di && !(flags & XATTR_REPLACE)) { |
142 | ret = -ENOSPC; | |
01e6deb2 LB |
143 | goto out; |
144 | } | |
5f5bc6b1 FM |
145 | } else if (ret == -EEXIST) { |
146 | ret = 0; | |
2ff7e61e | 147 | di = btrfs_match_dir_item_name(fs_info, path, name, name_len); |
5f5bc6b1 FM |
148 | ASSERT(di); /* logic error */ |
149 | } else if (ret) { | |
150 | goto out; | |
fa09200b | 151 | } |
5103e947 | 152 | |
5f5bc6b1 | 153 | if (di && (flags & XATTR_CREATE)) { |
ed3ee9f4 | 154 | ret = -EEXIST; |
5f5bc6b1 FM |
155 | goto out; |
156 | } | |
ed3ee9f4 | 157 | |
5f5bc6b1 | 158 | if (di) { |
fa09200b | 159 | /* |
5f5bc6b1 FM |
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. | |
fa09200b | 165 | */ |
5f5bc6b1 FM |
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) { | |
2ff7e61e | 176 | if (btrfs_leaf_free_space(fs_info, leaf) < |
5f5bc6b1 FM |
177 | (size - old_data_len)) { |
178 | ret = -ENOSPC; | |
179 | goto out; | |
180 | } | |
fa09200b | 181 | } |
33268eaf | 182 | |
5f5bc6b1 FM |
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) | |
2ff7e61e | 186 | btrfs_extend_item(fs_info, path, |
5f5bc6b1 FM |
187 | size - old_data_len); |
188 | else if (size < old_data_len) | |
2ff7e61e JM |
189 | btrfs_truncate_item(fs_info, path, |
190 | data_size, 1); | |
5f5bc6b1 FM |
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; | |
2ff7e61e | 196 | btrfs_extend_item(fs_info, path, data_size); |
5f5bc6b1 | 197 | } |
fa09200b | 198 | |
5f5bc6b1 FM |
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 { | |
fa09200b | 208 | /* |
5f5bc6b1 FM |
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. | |
fa09200b | 212 | */ |
5103e947 | 213 | } |
f34f57a3 YZ |
214 | out: |
215 | btrfs_free_path(path); | |
216 | return ret; | |
217 | } | |
218 | ||
4815053a DS |
219 | /* |
220 | * @value: "" makes the attribute to empty, NULL removes it | |
221 | */ | |
7852781d | 222 | int btrfs_setxattr(struct btrfs_trans_handle *trans, |
f34f57a3 YZ |
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 | ||
e0d46f5c AG |
229 | if (btrfs_root_readonly(root)) |
230 | return -EROFS; | |
231 | ||
f34f57a3 YZ |
232 | if (trans) |
233 | return do_setxattr(trans, inode, name, value, size, flags); | |
234 | ||
a22285a6 YZ |
235 | trans = btrfs_start_transaction(root, 2); |
236 | if (IS_ERR(trans)) | |
237 | return PTR_ERR(trans); | |
5103e947 | 238 | |
f34f57a3 YZ |
239 | ret = do_setxattr(trans, inode, name, value, size, flags); |
240 | if (ret) | |
241 | goto out; | |
242 | ||
0c4d2d95 | 243 | inode_inc_iversion(inode); |
c2050a45 | 244 | inode->i_ctime = current_time(inode); |
e9976151 | 245 | set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags); |
f34f57a3 YZ |
246 | ret = btrfs_update_inode(trans, root, inode); |
247 | BUG_ON(ret); | |
248 | out: | |
3a45bb20 | 249 | btrfs_end_transaction(trans); |
5103e947 JB |
250 | return ret; |
251 | } | |
252 | ||
253 | ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size) | |
254 | { | |
daac7ba6 | 255 | struct btrfs_key key; |
2b0143b5 | 256 | struct inode *inode = d_inode(dentry); |
5103e947 JB |
257 | struct btrfs_root *root = BTRFS_I(inode)->root; |
258 | struct btrfs_path *path; | |
daac7ba6 | 259 | int ret = 0; |
eaa47d86 | 260 | size_t total_size = 0, size_left = size; |
5103e947 JB |
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 | */ | |
4a0cc7ca | 267 | key.objectid = btrfs_ino(BTRFS_I(inode)); |
962a298f | 268 | key.type = BTRFS_XATTR_ITEM_KEY; |
5103e947 JB |
269 | key.offset = 0; |
270 | ||
271 | path = btrfs_alloc_path(); | |
5103e947 JB |
272 | if (!path) |
273 | return -ENOMEM; | |
e4058b54 | 274 | path->reada = READA_FORWARD; |
5103e947 | 275 | |
5103e947 JB |
276 | /* search for our xattrs */ |
277 | ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); | |
278 | if (ret < 0) | |
279 | goto err; | |
2e6a0035 | 280 | |
5103e947 | 281 | while (1) { |
daac7ba6 FM |
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 | ||
5103e947 | 289 | leaf = path->nodes[0]; |
5103e947 JB |
290 | slot = path->slots[0]; |
291 | ||
292 | /* this is where we start walking through the path */ | |
2e6a0035 | 293 | if (slot >= btrfs_header_nritems(leaf)) { |
5103e947 JB |
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 | */ | |
2e6a0035 LZ |
298 | ret = btrfs_next_leaf(root, path); |
299 | if (ret < 0) | |
300 | goto err; | |
301 | else if (ret > 0) | |
302 | break; | |
303 | continue; | |
5103e947 | 304 | } |
5103e947 | 305 | |
5103e947 JB |
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; | |
f1cd1f0b | 311 | if (found_key.type > BTRFS_XATTR_ITEM_KEY) |
5103e947 | 312 | break; |
f1cd1f0b | 313 | if (found_key.type < BTRFS_XATTR_ITEM_KEY) |
daac7ba6 | 314 | goto next_item; |
5103e947 JB |
315 | |
316 | di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item); | |
daac7ba6 FM |
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 | ||
daac7ba6 FM |
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; | |
5103e947 | 332 | |
daac7ba6 FM |
333 | if (!buffer || (name_len + 1) > size_left) { |
334 | ret = -ERANGE; | |
335 | goto err; | |
336 | } | |
5103e947 | 337 | |
daac7ba6 FM |
338 | read_extent_buffer(leaf, buffer, name_ptr, name_len); |
339 | buffer[name_len] = '\0'; | |
eaa47d86 | 340 | |
daac7ba6 FM |
341 | size_left -= name_len + 1; |
342 | buffer += name_len + 1; | |
2e6a0035 | 343 | next: |
daac7ba6 FM |
344 | cur += this_len; |
345 | di = (struct btrfs_dir_item *)((char *)di + this_len); | |
346 | } | |
347 | next_item: | |
2e6a0035 | 348 | path->slots[0]++; |
5103e947 JB |
349 | } |
350 | ret = total_size; | |
351 | ||
352 | err: | |
5103e947 JB |
353 | btrfs_free_path(path); |
354 | ||
355 | return ret; | |
356 | } | |
357 | ||
9172abbc | 358 | static int btrfs_xattr_handler_get(const struct xattr_handler *handler, |
b296821a AV |
359 | struct dentry *unused, struct inode *inode, |
360 | const char *name, void *buffer, size_t size) | |
95819c05 | 361 | { |
9172abbc | 362 | name = xattr_full_name(handler, name); |
7852781d | 363 | return btrfs_getxattr(inode, name, buffer, size); |
69a32ac5 CM |
364 | } |
365 | ||
9172abbc | 366 | static int btrfs_xattr_handler_set(const struct xattr_handler *handler, |
59301226 AV |
367 | struct dentry *unused, struct inode *inode, |
368 | const char *name, const void *buffer, | |
369 | size_t size, int flags) | |
95819c05 | 370 | { |
9172abbc | 371 | name = xattr_full_name(handler, name); |
7852781d | 372 | return btrfs_setxattr(NULL, inode, name, buffer, size, flags); |
9172abbc | 373 | } |
5103e947 | 374 | |
9172abbc | 375 | static int btrfs_xattr_handler_set_prop(const struct xattr_handler *handler, |
59301226 | 376 | struct dentry *unused, struct inode *inode, |
9172abbc AG |
377 | const char *name, const void *value, |
378 | size_t size, int flags) | |
379 | { | |
380 | name = xattr_full_name(handler, name); | |
59301226 | 381 | return btrfs_set_prop(inode, name, value, size, flags); |
95819c05 | 382 | } |
5103e947 | 383 | |
9172abbc AG |
384 | static 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 | ||
390 | static 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 | ||
396 | static 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 | ||
402 | static 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 | ||
408 | const 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 | ||
48a3b636 ES |
420 | static int btrfs_initxattrs(struct inode *inode, |
421 | const struct xattr *xattr_array, void *fs_info) | |
0279b4cd | 422 | { |
9d8f13ba MZ |
423 | const struct xattr *xattr; |
424 | struct btrfs_trans_handle *trans = fs_info; | |
0279b4cd | 425 | char *name; |
9d8f13ba | 426 | int err = 0; |
0279b4cd | 427 | |
9d8f13ba MZ |
428 | for (xattr = xattr_array; xattr->name != NULL; xattr++) { |
429 | name = kmalloc(XATTR_SECURITY_PREFIX_LEN + | |
39a27ec1 | 430 | strlen(xattr->name) + 1, GFP_KERNEL); |
9d8f13ba MZ |
431 | if (!name) { |
432 | err = -ENOMEM; | |
433 | break; | |
434 | } | |
0279b4cd | 435 | strcpy(name, XATTR_SECURITY_PREFIX); |
9d8f13ba | 436 | strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name); |
7852781d DS |
437 | err = btrfs_setxattr(trans, inode, name, xattr->value, |
438 | xattr->value_len, 0); | |
0279b4cd | 439 | kfree(name); |
9d8f13ba MZ |
440 | if (err < 0) |
441 | break; | |
0279b4cd | 442 | } |
0279b4cd JO |
443 | return err; |
444 | } | |
9d8f13ba MZ |
445 | |
446 | int 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 | } |