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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> |
827aa18e | 14 | #include <linux/sched/mm.h> |
5103e947 JB |
15 | #include "ctree.h" |
16 | #include "btrfs_inode.h" | |
17 | #include "transaction.h" | |
18 | #include "xattr.h" | |
19 | #include "disk-io.h" | |
63541927 | 20 | #include "props.h" |
5f5bc6b1 | 21 | #include "locking.h" |
33268eaf | 22 | |
bcadd705 | 23 | int btrfs_getxattr(struct inode *inode, const char *name, |
95819c05 | 24 | void *buffer, size_t size) |
5103e947 JB |
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; | |
5103e947 JB |
30 | int ret = 0; |
31 | unsigned long data_ptr; | |
5103e947 JB |
32 | |
33 | path = btrfs_alloc_path(); | |
95819c05 | 34 | if (!path) |
5103e947 | 35 | return -ENOMEM; |
5103e947 | 36 | |
5103e947 | 37 | /* lookup the xattr by name */ |
f85b7379 DS |
38 | di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(BTRFS_I(inode)), |
39 | name, strlen(name), 0); | |
07060404 | 40 | if (!di) { |
5103e947 JB |
41 | ret = -ENODATA; |
42 | goto out; | |
07060404 JB |
43 | } else if (IS_ERR(di)) { |
44 | ret = PTR_ERR(di); | |
45 | goto out; | |
5103e947 JB |
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 | } | |
07060404 JB |
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 | */ | |
5103e947 JB |
68 | data_ptr = (unsigned long)((char *)(di + 1) + |
69 | btrfs_dir_name_len(leaf, di)); | |
70 | read_extent_buffer(leaf, buffer, data_ptr, | |
3acd7ee8 | 71 | btrfs_dir_data_len(leaf, di)); |
5103e947 JB |
72 | ret = btrfs_dir_data_len(leaf, di); |
73 | ||
74 | out: | |
5103e947 JB |
75 | btrfs_free_path(path); |
76 | return ret; | |
77 | } | |
78 | ||
f34f57a3 YZ |
79 | static int do_setxattr(struct btrfs_trans_handle *trans, |
80 | struct inode *inode, const char *name, | |
81 | const void *value, size_t size, int flags) | |
5103e947 | 82 | { |
5f5bc6b1 | 83 | struct btrfs_dir_item *di = NULL; |
5103e947 | 84 | struct btrfs_root *root = BTRFS_I(inode)->root; |
2ff7e61e | 85 | struct btrfs_fs_info *fs_info = root->fs_info; |
5103e947 | 86 | struct btrfs_path *path; |
f34f57a3 YZ |
87 | size_t name_len = strlen(name); |
88 | int ret = 0; | |
89 | ||
da17066c | 90 | if (name_len + size > BTRFS_MAX_XATTR_SIZE(root->fs_info)) |
f34f57a3 | 91 | return -ENOSPC; |
5103e947 JB |
92 | |
93 | path = btrfs_alloc_path(); | |
95819c05 | 94 | if (!path) |
5103e947 | 95 | return -ENOMEM; |
5f5bc6b1 FM |
96 | path->skip_release_on_error = 1; |
97 | ||
98 | if (!value) { | |
f85b7379 DS |
99 | di = btrfs_lookup_xattr(trans, root, path, |
100 | btrfs_ino(BTRFS_I(inode)), name, name_len, -1); | |
5f5bc6b1 FM |
101 | if (!di && (flags & XATTR_REPLACE)) |
102 | ret = -ENODATA; | |
5cdf83ed FM |
103 | else if (IS_ERR(di)) |
104 | ret = PTR_ERR(di); | |
5f5bc6b1 FM |
105 | else if (di) |
106 | ret = btrfs_delete_one_dir_name(trans, root, path, di); | |
107 | goto out; | |
108 | } | |
5103e947 | 109 | |
5f5bc6b1 FM |
110 | /* |
111 | * For a replace we can't just do the insert blindly. | |
112 | * Do a lookup first (read-only btrfs_search_slot), and return if xattr | |
113 | * doesn't exist. If it exists, fall down below to the insert/replace | |
114 | * path - we can't race with a concurrent xattr delete, because the VFS | |
115 | * locks the inode's i_mutex before calling setxattr or removexattr. | |
116 | */ | |
fa09200b | 117 | if (flags & XATTR_REPLACE) { |
5955102c | 118 | ASSERT(inode_is_locked(inode)); |
f85b7379 DS |
119 | di = btrfs_lookup_xattr(NULL, root, path, |
120 | btrfs_ino(BTRFS_I(inode)), name, name_len, 0); | |
5cdf83ed | 121 | if (!di) |
fa09200b | 122 | ret = -ENODATA; |
5cdf83ed FM |
123 | else if (IS_ERR(di)) |
124 | ret = PTR_ERR(di); | |
125 | if (ret) | |
5103e947 | 126 | goto out; |
b3b4aa74 | 127 | btrfs_release_path(path); |
5f5bc6b1 FM |
128 | di = NULL; |
129 | } | |
4815053a | 130 | |
4a0cc7ca | 131 | ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(BTRFS_I(inode)), |
5f5bc6b1 FM |
132 | name, name_len, value, size); |
133 | if (ret == -EOVERFLOW) { | |
4815053a | 134 | /* |
5f5bc6b1 FM |
135 | * We have an existing item in a leaf, split_leaf couldn't |
136 | * expand it. That item might have or not a dir_item that | |
137 | * matches our target xattr, so lets check. | |
4815053a | 138 | */ |
5f5bc6b1 FM |
139 | ret = 0; |
140 | btrfs_assert_tree_locked(path->nodes[0]); | |
2ff7e61e | 141 | di = btrfs_match_dir_item_name(fs_info, path, name, name_len); |
5f5bc6b1 FM |
142 | if (!di && !(flags & XATTR_REPLACE)) { |
143 | ret = -ENOSPC; | |
01e6deb2 LB |
144 | goto out; |
145 | } | |
5f5bc6b1 FM |
146 | } else if (ret == -EEXIST) { |
147 | ret = 0; | |
2ff7e61e | 148 | di = btrfs_match_dir_item_name(fs_info, path, name, name_len); |
5f5bc6b1 FM |
149 | ASSERT(di); /* logic error */ |
150 | } else if (ret) { | |
151 | goto out; | |
fa09200b | 152 | } |
5103e947 | 153 | |
5f5bc6b1 | 154 | if (di && (flags & XATTR_CREATE)) { |
ed3ee9f4 | 155 | ret = -EEXIST; |
5f5bc6b1 FM |
156 | goto out; |
157 | } | |
ed3ee9f4 | 158 | |
5f5bc6b1 | 159 | if (di) { |
fa09200b | 160 | /* |
5f5bc6b1 FM |
161 | * We're doing a replace, and it must be atomic, that is, at |
162 | * any point in time we have either the old or the new xattr | |
163 | * value in the tree. We don't want readers (getxattr and | |
164 | * listxattrs) to miss a value, this is specially important | |
165 | * for ACLs. | |
fa09200b | 166 | */ |
5f5bc6b1 FM |
167 | const int slot = path->slots[0]; |
168 | struct extent_buffer *leaf = path->nodes[0]; | |
169 | const u16 old_data_len = btrfs_dir_data_len(leaf, di); | |
170 | const u32 item_size = btrfs_item_size_nr(leaf, slot); | |
171 | const u32 data_size = sizeof(*di) + name_len + size; | |
172 | struct btrfs_item *item; | |
173 | unsigned long data_ptr; | |
174 | char *ptr; | |
175 | ||
176 | if (size > old_data_len) { | |
e902baac | 177 | if (btrfs_leaf_free_space(leaf) < |
5f5bc6b1 FM |
178 | (size - old_data_len)) { |
179 | ret = -ENOSPC; | |
180 | goto out; | |
181 | } | |
fa09200b | 182 | } |
33268eaf | 183 | |
5f5bc6b1 FM |
184 | if (old_data_len + name_len + sizeof(*di) == item_size) { |
185 | /* No other xattrs packed in the same leaf item. */ | |
186 | if (size > old_data_len) | |
2ff7e61e | 187 | btrfs_extend_item(fs_info, path, |
5f5bc6b1 FM |
188 | size - old_data_len); |
189 | else if (size < old_data_len) | |
2ff7e61e JM |
190 | btrfs_truncate_item(fs_info, path, |
191 | data_size, 1); | |
5f5bc6b1 FM |
192 | } else { |
193 | /* There are other xattrs packed in the same item. */ | |
194 | ret = btrfs_delete_one_dir_name(trans, root, path, di); | |
195 | if (ret) | |
196 | goto out; | |
2ff7e61e | 197 | btrfs_extend_item(fs_info, path, data_size); |
5f5bc6b1 | 198 | } |
fa09200b | 199 | |
5f5bc6b1 FM |
200 | item = btrfs_item_nr(slot); |
201 | ptr = btrfs_item_ptr(leaf, slot, char); | |
202 | ptr += btrfs_item_size(leaf, item) - 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(leaf); | |
208 | } else { | |
fa09200b | 209 | /* |
5f5bc6b1 FM |
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. | |
fa09200b | 213 | */ |
5103e947 | 214 | } |
f34f57a3 YZ |
215 | out: |
216 | btrfs_free_path(path); | |
217 | return ret; | |
218 | } | |
219 | ||
4815053a DS |
220 | /* |
221 | * @value: "" makes the attribute to empty, NULL removes it | |
222 | */ | |
7852781d | 223 | int btrfs_setxattr(struct btrfs_trans_handle *trans, |
f34f57a3 YZ |
224 | struct inode *inode, const char *name, |
225 | const void *value, size_t size, int flags) | |
226 | { | |
227 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
228 | int ret; | |
229 | ||
e0d46f5c AG |
230 | if (btrfs_root_readonly(root)) |
231 | return -EROFS; | |
232 | ||
f34f57a3 YZ |
233 | if (trans) |
234 | return do_setxattr(trans, inode, name, value, size, flags); | |
235 | ||
a22285a6 YZ |
236 | trans = btrfs_start_transaction(root, 2); |
237 | if (IS_ERR(trans)) | |
238 | return PTR_ERR(trans); | |
5103e947 | 239 | |
f34f57a3 YZ |
240 | ret = do_setxattr(trans, inode, name, value, size, flags); |
241 | if (ret) | |
242 | goto out; | |
243 | ||
0c4d2d95 | 244 | inode_inc_iversion(inode); |
c2050a45 | 245 | inode->i_ctime = current_time(inode); |
e9976151 | 246 | set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags); |
f34f57a3 YZ |
247 | ret = btrfs_update_inode(trans, root, inode); |
248 | BUG_ON(ret); | |
249 | out: | |
3a45bb20 | 250 | btrfs_end_transaction(trans); |
5103e947 JB |
251 | return ret; |
252 | } | |
253 | ||
254 | ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size) | |
255 | { | |
daac7ba6 | 256 | struct btrfs_key key; |
2b0143b5 | 257 | struct inode *inode = d_inode(dentry); |
5103e947 JB |
258 | struct btrfs_root *root = BTRFS_I(inode)->root; |
259 | struct btrfs_path *path; | |
daac7ba6 | 260 | int ret = 0; |
eaa47d86 | 261 | size_t total_size = 0, size_left = size; |
5103e947 JB |
262 | |
263 | /* | |
264 | * ok we want all objects associated with this id. | |
265 | * NOTE: we set key.offset = 0; because we want to start with the | |
266 | * first xattr that we find and walk forward | |
267 | */ | |
4a0cc7ca | 268 | key.objectid = btrfs_ino(BTRFS_I(inode)); |
962a298f | 269 | key.type = BTRFS_XATTR_ITEM_KEY; |
5103e947 JB |
270 | key.offset = 0; |
271 | ||
272 | path = btrfs_alloc_path(); | |
5103e947 JB |
273 | if (!path) |
274 | return -ENOMEM; | |
e4058b54 | 275 | path->reada = READA_FORWARD; |
5103e947 | 276 | |
5103e947 JB |
277 | /* search for our xattrs */ |
278 | ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); | |
279 | if (ret < 0) | |
280 | goto err; | |
2e6a0035 | 281 | |
5103e947 | 282 | while (1) { |
daac7ba6 FM |
283 | struct extent_buffer *leaf; |
284 | int slot; | |
285 | struct btrfs_dir_item *di; | |
286 | struct btrfs_key found_key; | |
287 | u32 item_size; | |
288 | u32 cur; | |
289 | ||
5103e947 | 290 | leaf = path->nodes[0]; |
5103e947 JB |
291 | slot = path->slots[0]; |
292 | ||
293 | /* this is where we start walking through the path */ | |
2e6a0035 | 294 | if (slot >= btrfs_header_nritems(leaf)) { |
5103e947 JB |
295 | /* |
296 | * if we've reached the last slot in this leaf we need | |
297 | * to go to the next leaf and reset everything | |
298 | */ | |
2e6a0035 LZ |
299 | ret = btrfs_next_leaf(root, path); |
300 | if (ret < 0) | |
301 | goto err; | |
302 | else if (ret > 0) | |
303 | break; | |
304 | continue; | |
5103e947 | 305 | } |
5103e947 | 306 | |
5103e947 JB |
307 | btrfs_item_key_to_cpu(leaf, &found_key, slot); |
308 | ||
309 | /* check to make sure this item is what we want */ | |
310 | if (found_key.objectid != key.objectid) | |
311 | break; | |
f1cd1f0b | 312 | if (found_key.type > BTRFS_XATTR_ITEM_KEY) |
5103e947 | 313 | break; |
f1cd1f0b | 314 | if (found_key.type < BTRFS_XATTR_ITEM_KEY) |
daac7ba6 | 315 | goto next_item; |
5103e947 JB |
316 | |
317 | di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item); | |
daac7ba6 FM |
318 | item_size = btrfs_item_size_nr(leaf, slot); |
319 | cur = 0; | |
320 | while (cur < item_size) { | |
321 | u16 name_len = btrfs_dir_name_len(leaf, di); | |
322 | u16 data_len = btrfs_dir_data_len(leaf, di); | |
323 | u32 this_len = sizeof(*di) + name_len + data_len; | |
324 | unsigned long name_ptr = (unsigned long)(di + 1); | |
325 | ||
daac7ba6 FM |
326 | total_size += name_len + 1; |
327 | /* | |
328 | * We are just looking for how big our buffer needs to | |
329 | * be. | |
330 | */ | |
331 | if (!size) | |
332 | goto next; | |
5103e947 | 333 | |
daac7ba6 FM |
334 | if (!buffer || (name_len + 1) > size_left) { |
335 | ret = -ERANGE; | |
336 | goto err; | |
337 | } | |
5103e947 | 338 | |
daac7ba6 FM |
339 | read_extent_buffer(leaf, buffer, name_ptr, name_len); |
340 | buffer[name_len] = '\0'; | |
eaa47d86 | 341 | |
daac7ba6 FM |
342 | size_left -= name_len + 1; |
343 | buffer += name_len + 1; | |
2e6a0035 | 344 | next: |
daac7ba6 FM |
345 | cur += this_len; |
346 | di = (struct btrfs_dir_item *)((char *)di + this_len); | |
347 | } | |
348 | next_item: | |
2e6a0035 | 349 | path->slots[0]++; |
5103e947 JB |
350 | } |
351 | ret = total_size; | |
352 | ||
353 | err: | |
5103e947 JB |
354 | btrfs_free_path(path); |
355 | ||
356 | return ret; | |
357 | } | |
358 | ||
9172abbc | 359 | static int btrfs_xattr_handler_get(const struct xattr_handler *handler, |
b296821a AV |
360 | struct dentry *unused, struct inode *inode, |
361 | const char *name, void *buffer, size_t size) | |
95819c05 | 362 | { |
9172abbc | 363 | name = xattr_full_name(handler, name); |
7852781d | 364 | return btrfs_getxattr(inode, name, buffer, size); |
69a32ac5 CM |
365 | } |
366 | ||
9172abbc | 367 | static int btrfs_xattr_handler_set(const struct xattr_handler *handler, |
59301226 AV |
368 | struct dentry *unused, struct inode *inode, |
369 | const char *name, const void *buffer, | |
370 | size_t size, int flags) | |
95819c05 | 371 | { |
9172abbc | 372 | name = xattr_full_name(handler, name); |
7852781d | 373 | return btrfs_setxattr(NULL, inode, name, buffer, size, flags); |
9172abbc | 374 | } |
5103e947 | 375 | |
9172abbc | 376 | static int btrfs_xattr_handler_set_prop(const struct xattr_handler *handler, |
59301226 | 377 | struct dentry *unused, struct inode *inode, |
9172abbc AG |
378 | const char *name, const void *value, |
379 | size_t size, int flags) | |
380 | { | |
381 | name = xattr_full_name(handler, name); | |
262c96a3 | 382 | return btrfs_set_prop_trans(inode, name, value, size, flags); |
95819c05 | 383 | } |
5103e947 | 384 | |
9172abbc AG |
385 | static const struct xattr_handler btrfs_security_xattr_handler = { |
386 | .prefix = XATTR_SECURITY_PREFIX, | |
387 | .get = btrfs_xattr_handler_get, | |
388 | .set = btrfs_xattr_handler_set, | |
389 | }; | |
390 | ||
391 | static const struct xattr_handler btrfs_trusted_xattr_handler = { | |
392 | .prefix = XATTR_TRUSTED_PREFIX, | |
393 | .get = btrfs_xattr_handler_get, | |
394 | .set = btrfs_xattr_handler_set, | |
395 | }; | |
396 | ||
397 | static const struct xattr_handler btrfs_user_xattr_handler = { | |
398 | .prefix = XATTR_USER_PREFIX, | |
399 | .get = btrfs_xattr_handler_get, | |
400 | .set = btrfs_xattr_handler_set, | |
401 | }; | |
402 | ||
403 | static const struct xattr_handler btrfs_btrfs_xattr_handler = { | |
404 | .prefix = XATTR_BTRFS_PREFIX, | |
405 | .get = btrfs_xattr_handler_get, | |
406 | .set = btrfs_xattr_handler_set_prop, | |
407 | }; | |
408 | ||
409 | const struct xattr_handler *btrfs_xattr_handlers[] = { | |
410 | &btrfs_security_xattr_handler, | |
411 | #ifdef CONFIG_BTRFS_FS_POSIX_ACL | |
412 | &posix_acl_access_xattr_handler, | |
413 | &posix_acl_default_xattr_handler, | |
414 | #endif | |
415 | &btrfs_trusted_xattr_handler, | |
416 | &btrfs_user_xattr_handler, | |
417 | &btrfs_btrfs_xattr_handler, | |
418 | NULL, | |
419 | }; | |
420 | ||
48a3b636 | 421 | static int btrfs_initxattrs(struct inode *inode, |
419a6f30 | 422 | const struct xattr *xattr_array, void *fs_private) |
0279b4cd | 423 | { |
419a6f30 | 424 | struct btrfs_trans_handle *trans = fs_private; |
9d8f13ba | 425 | const struct xattr *xattr; |
827aa18e | 426 | unsigned int nofs_flag; |
0279b4cd | 427 | char *name; |
9d8f13ba | 428 | int err = 0; |
0279b4cd | 429 | |
827aa18e FM |
430 | /* |
431 | * We're holding a transaction handle, so use a NOFS memory allocation | |
432 | * context to avoid deadlock if reclaim happens. | |
433 | */ | |
434 | nofs_flag = memalloc_nofs_save(); | |
9d8f13ba MZ |
435 | for (xattr = xattr_array; xattr->name != NULL; xattr++) { |
436 | name = kmalloc(XATTR_SECURITY_PREFIX_LEN + | |
39a27ec1 | 437 | strlen(xattr->name) + 1, GFP_KERNEL); |
9d8f13ba MZ |
438 | if (!name) { |
439 | err = -ENOMEM; | |
440 | break; | |
441 | } | |
0279b4cd | 442 | strcpy(name, XATTR_SECURITY_PREFIX); |
9d8f13ba | 443 | strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name); |
7852781d DS |
444 | err = btrfs_setxattr(trans, inode, name, xattr->value, |
445 | xattr->value_len, 0); | |
0279b4cd | 446 | kfree(name); |
9d8f13ba MZ |
447 | if (err < 0) |
448 | break; | |
0279b4cd | 449 | } |
827aa18e | 450 | memalloc_nofs_restore(nofs_flag); |
0279b4cd JO |
451 | return err; |
452 | } | |
9d8f13ba MZ |
453 | |
454 | int btrfs_xattr_security_init(struct btrfs_trans_handle *trans, | |
455 | struct inode *inode, struct inode *dir, | |
456 | const struct qstr *qstr) | |
457 | { | |
458 | return security_inode_init_security(inode, dir, qstr, | |
459 | &btrfs_initxattrs, trans); | |
460 | } |