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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 | ||
3e125a74 AJ |
79 | int btrfs_setxattr(struct btrfs_trans_handle *trans, struct inode *inode, |
80 | const char *name, 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 | ||
04e6863b AJ |
89 | ASSERT(trans); |
90 | ||
da17066c | 91 | if (name_len + size > BTRFS_MAX_XATTR_SIZE(root->fs_info)) |
f34f57a3 | 92 | return -ENOSPC; |
5103e947 JB |
93 | |
94 | path = btrfs_alloc_path(); | |
95819c05 | 95 | if (!path) |
5103e947 | 96 | return -ENOMEM; |
5f5bc6b1 FM |
97 | path->skip_release_on_error = 1; |
98 | ||
99 | if (!value) { | |
f85b7379 DS |
100 | di = btrfs_lookup_xattr(trans, root, path, |
101 | btrfs_ino(BTRFS_I(inode)), name, name_len, -1); | |
5f5bc6b1 FM |
102 | if (!di && (flags & XATTR_REPLACE)) |
103 | ret = -ENODATA; | |
5cdf83ed FM |
104 | else if (IS_ERR(di)) |
105 | ret = PTR_ERR(di); | |
5f5bc6b1 FM |
106 | else if (di) |
107 | ret = btrfs_delete_one_dir_name(trans, root, path, di); | |
108 | goto out; | |
109 | } | |
5103e947 | 110 | |
5f5bc6b1 FM |
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 | */ | |
fa09200b | 118 | if (flags & XATTR_REPLACE) { |
5955102c | 119 | ASSERT(inode_is_locked(inode)); |
f85b7379 DS |
120 | di = btrfs_lookup_xattr(NULL, root, path, |
121 | btrfs_ino(BTRFS_I(inode)), name, name_len, 0); | |
5cdf83ed | 122 | if (!di) |
fa09200b | 123 | ret = -ENODATA; |
5cdf83ed FM |
124 | else if (IS_ERR(di)) |
125 | ret = PTR_ERR(di); | |
126 | if (ret) | |
5103e947 | 127 | goto out; |
b3b4aa74 | 128 | btrfs_release_path(path); |
5f5bc6b1 FM |
129 | di = NULL; |
130 | } | |
4815053a | 131 | |
4a0cc7ca | 132 | ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(BTRFS_I(inode)), |
5f5bc6b1 FM |
133 | name, name_len, value, size); |
134 | if (ret == -EOVERFLOW) { | |
4815053a | 135 | /* |
5f5bc6b1 FM |
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. | |
4815053a | 139 | */ |
5f5bc6b1 FM |
140 | ret = 0; |
141 | btrfs_assert_tree_locked(path->nodes[0]); | |
2ff7e61e | 142 | di = btrfs_match_dir_item_name(fs_info, path, name, name_len); |
5f5bc6b1 FM |
143 | if (!di && !(flags & XATTR_REPLACE)) { |
144 | ret = -ENOSPC; | |
01e6deb2 LB |
145 | goto out; |
146 | } | |
5f5bc6b1 FM |
147 | } else if (ret == -EEXIST) { |
148 | ret = 0; | |
2ff7e61e | 149 | di = btrfs_match_dir_item_name(fs_info, path, name, name_len); |
5f5bc6b1 FM |
150 | ASSERT(di); /* logic error */ |
151 | } else if (ret) { | |
152 | goto out; | |
fa09200b | 153 | } |
5103e947 | 154 | |
5f5bc6b1 | 155 | if (di && (flags & XATTR_CREATE)) { |
ed3ee9f4 | 156 | ret = -EEXIST; |
5f5bc6b1 FM |
157 | goto out; |
158 | } | |
ed3ee9f4 | 159 | |
5f5bc6b1 | 160 | if (di) { |
fa09200b | 161 | /* |
5f5bc6b1 FM |
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. | |
fa09200b | 167 | */ |
5f5bc6b1 FM |
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) { | |
e902baac | 178 | if (btrfs_leaf_free_space(leaf) < |
5f5bc6b1 FM |
179 | (size - old_data_len)) { |
180 | ret = -ENOSPC; | |
181 | goto out; | |
182 | } | |
fa09200b | 183 | } |
33268eaf | 184 | |
5f5bc6b1 FM |
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) | |
c71dd880 | 188 | btrfs_extend_item(path, size - old_data_len); |
5f5bc6b1 | 189 | else if (size < old_data_len) |
78ac4f9e | 190 | btrfs_truncate_item(path, 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; | |
c71dd880 | 196 | btrfs_extend_item(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 | */ | |
e3de9b15 | 222 | int btrfs_setxattr_trans(struct inode *inode, const char *name, |
cac237ae | 223 | const void *value, size_t size, int flags) |
f34f57a3 YZ |
224 | { |
225 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
e3de9b15 | 226 | struct btrfs_trans_handle *trans; |
f34f57a3 YZ |
227 | int ret; |
228 | ||
a22285a6 YZ |
229 | trans = btrfs_start_transaction(root, 2); |
230 | if (IS_ERR(trans)) | |
231 | return PTR_ERR(trans); | |
5103e947 | 232 | |
2d74fa3e | 233 | ret = btrfs_setxattr(trans, inode, name, value, size, flags); |
f34f57a3 YZ |
234 | if (ret) |
235 | goto out; | |
236 | ||
0c4d2d95 | 237 | inode_inc_iversion(inode); |
c2050a45 | 238 | inode->i_ctime = current_time(inode); |
e9976151 | 239 | set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags); |
f34f57a3 YZ |
240 | ret = btrfs_update_inode(trans, root, inode); |
241 | BUG_ON(ret); | |
242 | out: | |
3a45bb20 | 243 | btrfs_end_transaction(trans); |
5103e947 JB |
244 | return ret; |
245 | } | |
246 | ||
247 | ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size) | |
248 | { | |
daac7ba6 | 249 | struct btrfs_key key; |
2b0143b5 | 250 | struct inode *inode = d_inode(dentry); |
5103e947 JB |
251 | struct btrfs_root *root = BTRFS_I(inode)->root; |
252 | struct btrfs_path *path; | |
daac7ba6 | 253 | int ret = 0; |
eaa47d86 | 254 | size_t total_size = 0, size_left = size; |
5103e947 JB |
255 | |
256 | /* | |
257 | * ok we want all objects associated with this id. | |
258 | * NOTE: we set key.offset = 0; because we want to start with the | |
259 | * first xattr that we find and walk forward | |
260 | */ | |
4a0cc7ca | 261 | key.objectid = btrfs_ino(BTRFS_I(inode)); |
962a298f | 262 | key.type = BTRFS_XATTR_ITEM_KEY; |
5103e947 JB |
263 | key.offset = 0; |
264 | ||
265 | path = btrfs_alloc_path(); | |
5103e947 JB |
266 | if (!path) |
267 | return -ENOMEM; | |
e4058b54 | 268 | path->reada = READA_FORWARD; |
5103e947 | 269 | |
5103e947 JB |
270 | /* search for our xattrs */ |
271 | ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); | |
272 | if (ret < 0) | |
273 | goto err; | |
2e6a0035 | 274 | |
5103e947 | 275 | while (1) { |
daac7ba6 FM |
276 | struct extent_buffer *leaf; |
277 | int slot; | |
278 | struct btrfs_dir_item *di; | |
279 | struct btrfs_key found_key; | |
280 | u32 item_size; | |
281 | u32 cur; | |
282 | ||
5103e947 | 283 | leaf = path->nodes[0]; |
5103e947 JB |
284 | slot = path->slots[0]; |
285 | ||
286 | /* this is where we start walking through the path */ | |
2e6a0035 | 287 | if (slot >= btrfs_header_nritems(leaf)) { |
5103e947 JB |
288 | /* |
289 | * if we've reached the last slot in this leaf we need | |
290 | * to go to the next leaf and reset everything | |
291 | */ | |
2e6a0035 LZ |
292 | ret = btrfs_next_leaf(root, path); |
293 | if (ret < 0) | |
294 | goto err; | |
295 | else if (ret > 0) | |
296 | break; | |
297 | continue; | |
5103e947 | 298 | } |
5103e947 | 299 | |
5103e947 JB |
300 | btrfs_item_key_to_cpu(leaf, &found_key, slot); |
301 | ||
302 | /* check to make sure this item is what we want */ | |
303 | if (found_key.objectid != key.objectid) | |
304 | break; | |
f1cd1f0b | 305 | if (found_key.type > BTRFS_XATTR_ITEM_KEY) |
5103e947 | 306 | break; |
f1cd1f0b | 307 | if (found_key.type < BTRFS_XATTR_ITEM_KEY) |
daac7ba6 | 308 | goto next_item; |
5103e947 JB |
309 | |
310 | di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item); | |
daac7ba6 FM |
311 | item_size = btrfs_item_size_nr(leaf, slot); |
312 | cur = 0; | |
313 | while (cur < item_size) { | |
314 | u16 name_len = btrfs_dir_name_len(leaf, di); | |
315 | u16 data_len = btrfs_dir_data_len(leaf, di); | |
316 | u32 this_len = sizeof(*di) + name_len + data_len; | |
317 | unsigned long name_ptr = (unsigned long)(di + 1); | |
318 | ||
daac7ba6 FM |
319 | total_size += name_len + 1; |
320 | /* | |
321 | * We are just looking for how big our buffer needs to | |
322 | * be. | |
323 | */ | |
324 | if (!size) | |
325 | goto next; | |
5103e947 | 326 | |
daac7ba6 FM |
327 | if (!buffer || (name_len + 1) > size_left) { |
328 | ret = -ERANGE; | |
329 | goto err; | |
330 | } | |
5103e947 | 331 | |
daac7ba6 FM |
332 | read_extent_buffer(leaf, buffer, name_ptr, name_len); |
333 | buffer[name_len] = '\0'; | |
eaa47d86 | 334 | |
daac7ba6 FM |
335 | size_left -= name_len + 1; |
336 | buffer += name_len + 1; | |
2e6a0035 | 337 | next: |
daac7ba6 FM |
338 | cur += this_len; |
339 | di = (struct btrfs_dir_item *)((char *)di + this_len); | |
340 | } | |
341 | next_item: | |
2e6a0035 | 342 | path->slots[0]++; |
5103e947 JB |
343 | } |
344 | ret = total_size; | |
345 | ||
346 | err: | |
5103e947 JB |
347 | btrfs_free_path(path); |
348 | ||
349 | return ret; | |
350 | } | |
351 | ||
9172abbc | 352 | static int btrfs_xattr_handler_get(const struct xattr_handler *handler, |
b296821a AV |
353 | struct dentry *unused, struct inode *inode, |
354 | const char *name, void *buffer, size_t size) | |
95819c05 | 355 | { |
9172abbc | 356 | name = xattr_full_name(handler, name); |
7852781d | 357 | return btrfs_getxattr(inode, name, buffer, size); |
69a32ac5 CM |
358 | } |
359 | ||
9172abbc | 360 | static int btrfs_xattr_handler_set(const struct xattr_handler *handler, |
59301226 AV |
361 | struct dentry *unused, struct inode *inode, |
362 | const char *name, const void *buffer, | |
363 | size_t size, int flags) | |
95819c05 | 364 | { |
9172abbc | 365 | name = xattr_full_name(handler, name); |
e3de9b15 | 366 | return btrfs_setxattr_trans(inode, name, buffer, size, flags); |
9172abbc | 367 | } |
5103e947 | 368 | |
9172abbc | 369 | static int btrfs_xattr_handler_set_prop(const struct xattr_handler *handler, |
59301226 | 370 | struct dentry *unused, struct inode *inode, |
9172abbc AG |
371 | const char *name, const void *value, |
372 | size_t size, int flags) | |
373 | { | |
f22125e5 AJ |
374 | int ret; |
375 | ||
9172abbc | 376 | name = xattr_full_name(handler, name); |
f22125e5 AJ |
377 | ret = btrfs_validate_prop(name, value, size); |
378 | if (ret) | |
379 | return ret; | |
262c96a3 | 380 | return btrfs_set_prop_trans(inode, name, value, size, flags); |
95819c05 | 381 | } |
5103e947 | 382 | |
9172abbc AG |
383 | static const struct xattr_handler btrfs_security_xattr_handler = { |
384 | .prefix = XATTR_SECURITY_PREFIX, | |
385 | .get = btrfs_xattr_handler_get, | |
386 | .set = btrfs_xattr_handler_set, | |
387 | }; | |
388 | ||
389 | static const struct xattr_handler btrfs_trusted_xattr_handler = { | |
390 | .prefix = XATTR_TRUSTED_PREFIX, | |
391 | .get = btrfs_xattr_handler_get, | |
392 | .set = btrfs_xattr_handler_set, | |
393 | }; | |
394 | ||
395 | static const struct xattr_handler btrfs_user_xattr_handler = { | |
396 | .prefix = XATTR_USER_PREFIX, | |
397 | .get = btrfs_xattr_handler_get, | |
398 | .set = btrfs_xattr_handler_set, | |
399 | }; | |
400 | ||
401 | static const struct xattr_handler btrfs_btrfs_xattr_handler = { | |
402 | .prefix = XATTR_BTRFS_PREFIX, | |
403 | .get = btrfs_xattr_handler_get, | |
404 | .set = btrfs_xattr_handler_set_prop, | |
405 | }; | |
406 | ||
407 | const struct xattr_handler *btrfs_xattr_handlers[] = { | |
408 | &btrfs_security_xattr_handler, | |
409 | #ifdef CONFIG_BTRFS_FS_POSIX_ACL | |
410 | &posix_acl_access_xattr_handler, | |
411 | &posix_acl_default_xattr_handler, | |
412 | #endif | |
413 | &btrfs_trusted_xattr_handler, | |
414 | &btrfs_user_xattr_handler, | |
415 | &btrfs_btrfs_xattr_handler, | |
416 | NULL, | |
417 | }; | |
418 | ||
48a3b636 | 419 | static int btrfs_initxattrs(struct inode *inode, |
419a6f30 | 420 | const struct xattr *xattr_array, void *fs_private) |
0279b4cd | 421 | { |
419a6f30 | 422 | struct btrfs_trans_handle *trans = fs_private; |
9d8f13ba | 423 | const struct xattr *xattr; |
827aa18e | 424 | unsigned int nofs_flag; |
0279b4cd | 425 | char *name; |
9d8f13ba | 426 | int err = 0; |
0279b4cd | 427 | |
827aa18e FM |
428 | /* |
429 | * We're holding a transaction handle, so use a NOFS memory allocation | |
430 | * context to avoid deadlock if reclaim happens. | |
431 | */ | |
432 | nofs_flag = memalloc_nofs_save(); | |
9d8f13ba MZ |
433 | for (xattr = xattr_array; xattr->name != NULL; xattr++) { |
434 | name = kmalloc(XATTR_SECURITY_PREFIX_LEN + | |
39a27ec1 | 435 | strlen(xattr->name) + 1, GFP_KERNEL); |
9d8f13ba MZ |
436 | if (!name) { |
437 | err = -ENOMEM; | |
438 | break; | |
439 | } | |
0279b4cd | 440 | strcpy(name, XATTR_SECURITY_PREFIX); |
9d8f13ba | 441 | strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name); |
04e6863b AJ |
442 | err = btrfs_setxattr(trans, inode, name, xattr->value, |
443 | xattr->value_len, 0); | |
0279b4cd | 444 | kfree(name); |
9d8f13ba MZ |
445 | if (err < 0) |
446 | break; | |
0279b4cd | 447 | } |
827aa18e | 448 | memalloc_nofs_restore(nofs_flag); |
0279b4cd JO |
449 | return err; |
450 | } | |
9d8f13ba MZ |
451 | |
452 | int btrfs_xattr_security_init(struct btrfs_trans_handle *trans, | |
453 | struct inode *inode, struct inode *dir, | |
454 | const struct qstr *qstr) | |
455 | { | |
456 | return security_inode_init_security(inode, dir, qstr, | |
457 | &btrfs_initxattrs, trans); | |
458 | } |