xref: /linux/fs/hfsplus/xattr.c (revision ff9a79307f89563da6d841da8b7cc4a0afceb0e2)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * linux/fs/hfsplus/xattr.c
4  *
5  * Vyacheslav Dubeyko <slava@dubeyko.com>
6  *
7  * Logic of processing extended attributes
8  */
9 
10 #include "hfsplus_fs.h"
11 #include <linux/nls.h>
12 #include "xattr.h"
13 
14 static int hfsplus_removexattr(struct inode *inode, const char *name);
15 
16 const struct xattr_handler * const hfsplus_xattr_handlers[] = {
17 	&hfsplus_xattr_osx_handler,
18 	&hfsplus_xattr_user_handler,
19 	&hfsplus_xattr_trusted_handler,
20 	&hfsplus_xattr_security_handler,
21 	NULL
22 };
23 
24 static int strcmp_xattr_finder_info(const char *name)
25 {
26 	if (name) {
27 		return strncmp(name, HFSPLUS_XATTR_FINDER_INFO_NAME,
28 				sizeof(HFSPLUS_XATTR_FINDER_INFO_NAME));
29 	}
30 	return -1;
31 }
32 
33 static int strcmp_xattr_acl(const char *name)
34 {
35 	if (name) {
36 		return strncmp(name, HFSPLUS_XATTR_ACL_NAME,
37 				sizeof(HFSPLUS_XATTR_ACL_NAME));
38 	}
39 	return -1;
40 }
41 
42 static bool is_known_namespace(const char *name)
43 {
44 	if (strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) &&
45 	    strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN) &&
46 	    strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) &&
47 	    strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN))
48 		return false;
49 
50 	return true;
51 }
52 
53 static void hfsplus_init_header_node(struct inode *attr_file,
54 					u32 clump_size,
55 					char *buf, u16 node_size)
56 {
57 	struct hfs_bnode_desc *desc;
58 	struct hfs_btree_header_rec *head;
59 	u16 offset;
60 	__be16 *rec_offsets;
61 	u32 hdr_node_map_rec_bits;
62 	char *bmp;
63 	u32 used_nodes;
64 	u32 used_bmp_bytes;
65 	u64 tmp;
66 
67 	hfs_dbg(ATTR_MOD, "init_hdr_attr_file: clump %u, node_size %u\n",
68 		clump_size, node_size);
69 
70 	/* The end of the node contains list of record offsets */
71 	rec_offsets = (__be16 *)(buf + node_size);
72 
73 	desc = (struct hfs_bnode_desc *)buf;
74 	desc->type = HFS_NODE_HEADER;
75 	desc->num_recs = cpu_to_be16(HFSPLUS_BTREE_HDR_NODE_RECS_COUNT);
76 	offset = sizeof(struct hfs_bnode_desc);
77 	*--rec_offsets = cpu_to_be16(offset);
78 
79 	head = (struct hfs_btree_header_rec *)(buf + offset);
80 	head->node_size = cpu_to_be16(node_size);
81 	tmp = i_size_read(attr_file);
82 	do_div(tmp, node_size);
83 	head->node_count = cpu_to_be32(tmp);
84 	head->free_nodes = cpu_to_be32(be32_to_cpu(head->node_count) - 1);
85 	head->clump_size = cpu_to_be32(clump_size);
86 	head->attributes |= cpu_to_be32(HFS_TREE_BIGKEYS | HFS_TREE_VARIDXKEYS);
87 	head->max_key_len = cpu_to_be16(HFSPLUS_ATTR_KEYLEN - sizeof(u16));
88 	offset += sizeof(struct hfs_btree_header_rec);
89 	*--rec_offsets = cpu_to_be16(offset);
90 	offset += HFSPLUS_BTREE_HDR_USER_BYTES;
91 	*--rec_offsets = cpu_to_be16(offset);
92 
93 	hdr_node_map_rec_bits = 8 * (node_size - offset - (4 * sizeof(u16)));
94 	if (be32_to_cpu(head->node_count) > hdr_node_map_rec_bits) {
95 		u32 map_node_bits;
96 		u32 map_nodes;
97 
98 		desc->next = cpu_to_be32(be32_to_cpu(head->leaf_tail) + 1);
99 		map_node_bits = 8 * (node_size - sizeof(struct hfs_bnode_desc) -
100 					(2 * sizeof(u16)) - 2);
101 		map_nodes = (be32_to_cpu(head->node_count) -
102 				hdr_node_map_rec_bits +
103 				(map_node_bits - 1)) / map_node_bits;
104 		be32_add_cpu(&head->free_nodes, 0 - map_nodes);
105 	}
106 
107 	bmp = buf + offset;
108 	used_nodes =
109 		be32_to_cpu(head->node_count) - be32_to_cpu(head->free_nodes);
110 	used_bmp_bytes = used_nodes / 8;
111 	if (used_bmp_bytes) {
112 		memset(bmp, 0xFF, used_bmp_bytes);
113 		bmp += used_bmp_bytes;
114 		used_nodes %= 8;
115 	}
116 	*bmp = ~(0xFF >> used_nodes);
117 	offset += hdr_node_map_rec_bits / 8;
118 	*--rec_offsets = cpu_to_be16(offset);
119 }
120 
121 static int hfsplus_create_attributes_file(struct super_block *sb)
122 {
123 	int err = 0;
124 	struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
125 	struct inode *attr_file;
126 	struct hfsplus_inode_info *hip;
127 	u32 clump_size;
128 	u16 node_size = HFSPLUS_ATTR_TREE_NODE_SIZE;
129 	char *buf;
130 	int index, written;
131 	struct address_space *mapping;
132 	struct page *page;
133 	int old_state = HFSPLUS_EMPTY_ATTR_TREE;
134 
135 	hfs_dbg(ATTR_MOD, "create_attr_file: ino %d\n", HFSPLUS_ATTR_CNID);
136 
137 check_attr_tree_state_again:
138 	switch (atomic_read(&sbi->attr_tree_state)) {
139 	case HFSPLUS_EMPTY_ATTR_TREE:
140 		if (old_state != atomic_cmpxchg(&sbi->attr_tree_state,
141 						old_state,
142 						HFSPLUS_CREATING_ATTR_TREE))
143 			goto check_attr_tree_state_again;
144 		break;
145 	case HFSPLUS_CREATING_ATTR_TREE:
146 		/*
147 		 * This state means that another thread is in process
148 		 * of AttributesFile creation. Theoretically, it is
149 		 * possible to be here. But really __setxattr() method
150 		 * first of all calls hfs_find_init() for lookup in
151 		 * B-tree of CatalogFile. This method locks mutex of
152 		 * CatalogFile's B-tree. As a result, if some thread
153 		 * is inside AttributedFile creation operation then
154 		 * another threads will be waiting unlocking of
155 		 * CatalogFile's B-tree's mutex. However, if code will
156 		 * change then we will return error code (-EAGAIN) from
157 		 * here. Really, it means that first try to set of xattr
158 		 * fails with error but second attempt will have success.
159 		 */
160 		return -EAGAIN;
161 	case HFSPLUS_VALID_ATTR_TREE:
162 		return 0;
163 	case HFSPLUS_FAILED_ATTR_TREE:
164 		return -EOPNOTSUPP;
165 	default:
166 		BUG();
167 	}
168 
169 	attr_file = hfsplus_iget(sb, HFSPLUS_ATTR_CNID);
170 	if (IS_ERR(attr_file)) {
171 		pr_err("failed to load attributes file\n");
172 		return PTR_ERR(attr_file);
173 	}
174 
175 	BUG_ON(i_size_read(attr_file) != 0);
176 
177 	hip = HFSPLUS_I(attr_file);
178 
179 	clump_size = hfsplus_calc_btree_clump_size(sb->s_blocksize,
180 						    node_size,
181 						    sbi->sect_count,
182 						    HFSPLUS_ATTR_CNID);
183 
184 	mutex_lock(&hip->extents_lock);
185 	hip->clump_blocks = clump_size >> sbi->alloc_blksz_shift;
186 	mutex_unlock(&hip->extents_lock);
187 
188 	if (sbi->free_blocks <= (hip->clump_blocks << 1)) {
189 		err = -ENOSPC;
190 		goto end_attr_file_creation;
191 	}
192 
193 	while (hip->alloc_blocks < hip->clump_blocks) {
194 		err = hfsplus_file_extend(attr_file, false);
195 		if (unlikely(err)) {
196 			pr_err("failed to extend attributes file\n");
197 			goto end_attr_file_creation;
198 		}
199 		hip->phys_size = attr_file->i_size =
200 			(loff_t)hip->alloc_blocks << sbi->alloc_blksz_shift;
201 		hip->fs_blocks = hip->alloc_blocks << sbi->fs_shift;
202 		inode_set_bytes(attr_file, attr_file->i_size);
203 	}
204 
205 	buf = kzalloc(node_size, GFP_NOFS);
206 	if (!buf) {
207 		err = -ENOMEM;
208 		goto end_attr_file_creation;
209 	}
210 
211 	hfsplus_init_header_node(attr_file, clump_size, buf, node_size);
212 
213 	mapping = attr_file->i_mapping;
214 
215 	index = 0;
216 	written = 0;
217 	for (; written < node_size; index++, written += PAGE_SIZE) {
218 		void *kaddr;
219 
220 		page = read_mapping_page(mapping, index, NULL);
221 		if (IS_ERR(page)) {
222 			err = PTR_ERR(page);
223 			goto failed_header_node_init;
224 		}
225 
226 		kaddr = kmap_atomic(page);
227 		memcpy(kaddr, buf + written,
228 			min_t(size_t, PAGE_SIZE, node_size - written));
229 		kunmap_atomic(kaddr);
230 
231 		set_page_dirty(page);
232 		put_page(page);
233 	}
234 
235 	hfsplus_mark_inode_dirty(attr_file, HFSPLUS_I_ATTR_DIRTY);
236 
237 	sbi->attr_tree = hfs_btree_open(sb, HFSPLUS_ATTR_CNID);
238 	if (!sbi->attr_tree)
239 		pr_err("failed to load attributes file\n");
240 
241 failed_header_node_init:
242 	kfree(buf);
243 
244 end_attr_file_creation:
245 	iput(attr_file);
246 
247 	if (!err)
248 		atomic_set(&sbi->attr_tree_state, HFSPLUS_VALID_ATTR_TREE);
249 	else if (err == -ENOSPC)
250 		atomic_set(&sbi->attr_tree_state, HFSPLUS_EMPTY_ATTR_TREE);
251 	else
252 		atomic_set(&sbi->attr_tree_state, HFSPLUS_FAILED_ATTR_TREE);
253 
254 	return err;
255 }
256 
257 int __hfsplus_setxattr(struct inode *inode, const char *name,
258 			const void *value, size_t size, int flags)
259 {
260 	int err;
261 	struct hfs_find_data cat_fd;
262 	hfsplus_cat_entry entry;
263 	u16 cat_entry_flags, cat_entry_type;
264 	u16 folder_finderinfo_len = sizeof(struct DInfo) +
265 					sizeof(struct DXInfo);
266 	u16 file_finderinfo_len = sizeof(struct FInfo) +
267 					sizeof(struct FXInfo);
268 
269 	if ((!S_ISREG(inode->i_mode) &&
270 			!S_ISDIR(inode->i_mode)) ||
271 				HFSPLUS_IS_RSRC(inode))
272 		return -EOPNOTSUPP;
273 
274 	if (value == NULL)
275 		return hfsplus_removexattr(inode, name);
276 
277 	err = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &cat_fd);
278 	if (err) {
279 		pr_err("can't init xattr find struct\n");
280 		return err;
281 	}
282 
283 	err = hfsplus_find_cat(inode->i_sb, inode->i_ino, &cat_fd);
284 	if (err) {
285 		pr_err("catalog searching failed\n");
286 		goto end_setxattr;
287 	}
288 
289 	if (!strcmp_xattr_finder_info(name)) {
290 		if (flags & XATTR_CREATE) {
291 			pr_err("xattr exists yet\n");
292 			err = -EOPNOTSUPP;
293 			goto end_setxattr;
294 		}
295 		hfs_bnode_read(cat_fd.bnode, &entry, cat_fd.entryoffset,
296 					sizeof(hfsplus_cat_entry));
297 		if (be16_to_cpu(entry.type) == HFSPLUS_FOLDER) {
298 			if (size == folder_finderinfo_len) {
299 				memcpy(&entry.folder.info, value,
300 						folder_finderinfo_len);
301 				hfs_bnode_write(cat_fd.bnode, &entry,
302 					cat_fd.entryoffset,
303 					sizeof(struct hfsplus_cat_folder));
304 				hfsplus_mark_inode_dirty(inode,
305 						HFSPLUS_I_CAT_DIRTY);
306 			} else {
307 				err = -ERANGE;
308 				goto end_setxattr;
309 			}
310 		} else if (be16_to_cpu(entry.type) == HFSPLUS_FILE) {
311 			if (size == file_finderinfo_len) {
312 				memcpy(&entry.file.info, value,
313 						file_finderinfo_len);
314 				hfs_bnode_write(cat_fd.bnode, &entry,
315 					cat_fd.entryoffset,
316 					sizeof(struct hfsplus_cat_file));
317 				hfsplus_mark_inode_dirty(inode,
318 						HFSPLUS_I_CAT_DIRTY);
319 			} else {
320 				err = -ERANGE;
321 				goto end_setxattr;
322 			}
323 		} else {
324 			err = -EOPNOTSUPP;
325 			goto end_setxattr;
326 		}
327 		goto end_setxattr;
328 	}
329 
330 	if (!HFSPLUS_SB(inode->i_sb)->attr_tree) {
331 		err = hfsplus_create_attributes_file(inode->i_sb);
332 		if (unlikely(err))
333 			goto end_setxattr;
334 	}
335 
336 	if (hfsplus_attr_exists(inode, name)) {
337 		if (flags & XATTR_CREATE) {
338 			pr_err("xattr exists yet\n");
339 			err = -EOPNOTSUPP;
340 			goto end_setxattr;
341 		}
342 		err = hfsplus_delete_attr(inode, name);
343 		if (err)
344 			goto end_setxattr;
345 		err = hfsplus_create_attr(inode, name, value, size);
346 		if (err)
347 			goto end_setxattr;
348 	} else {
349 		if (flags & XATTR_REPLACE) {
350 			pr_err("cannot replace xattr\n");
351 			err = -EOPNOTSUPP;
352 			goto end_setxattr;
353 		}
354 		err = hfsplus_create_attr(inode, name, value, size);
355 		if (err)
356 			goto end_setxattr;
357 	}
358 
359 	cat_entry_type = hfs_bnode_read_u16(cat_fd.bnode, cat_fd.entryoffset);
360 	if (cat_entry_type == HFSPLUS_FOLDER) {
361 		cat_entry_flags = hfs_bnode_read_u16(cat_fd.bnode,
362 				    cat_fd.entryoffset +
363 				    offsetof(struct hfsplus_cat_folder, flags));
364 		cat_entry_flags |= HFSPLUS_XATTR_EXISTS;
365 		if (!strcmp_xattr_acl(name))
366 			cat_entry_flags |= HFSPLUS_ACL_EXISTS;
367 		hfs_bnode_write_u16(cat_fd.bnode, cat_fd.entryoffset +
368 				offsetof(struct hfsplus_cat_folder, flags),
369 				cat_entry_flags);
370 		hfsplus_mark_inode_dirty(inode, HFSPLUS_I_CAT_DIRTY);
371 	} else if (cat_entry_type == HFSPLUS_FILE) {
372 		cat_entry_flags = hfs_bnode_read_u16(cat_fd.bnode,
373 				    cat_fd.entryoffset +
374 				    offsetof(struct hfsplus_cat_file, flags));
375 		cat_entry_flags |= HFSPLUS_XATTR_EXISTS;
376 		if (!strcmp_xattr_acl(name))
377 			cat_entry_flags |= HFSPLUS_ACL_EXISTS;
378 		hfs_bnode_write_u16(cat_fd.bnode, cat_fd.entryoffset +
379 				    offsetof(struct hfsplus_cat_file, flags),
380 				    cat_entry_flags);
381 		hfsplus_mark_inode_dirty(inode, HFSPLUS_I_CAT_DIRTY);
382 	} else {
383 		pr_err("invalid catalog entry type\n");
384 		err = -EIO;
385 		goto end_setxattr;
386 	}
387 
388 end_setxattr:
389 	hfs_find_exit(&cat_fd);
390 	return err;
391 }
392 
393 static int name_len(const char *xattr_name, int xattr_name_len)
394 {
395 	int len = xattr_name_len + 1;
396 
397 	if (!is_known_namespace(xattr_name))
398 		len += XATTR_MAC_OSX_PREFIX_LEN;
399 
400 	return len;
401 }
402 
403 static ssize_t copy_name(char *buffer, const char *xattr_name, int name_len)
404 {
405 	ssize_t len;
406 
407 	if (!is_known_namespace(xattr_name))
408 		len = scnprintf(buffer, name_len + XATTR_MAC_OSX_PREFIX_LEN,
409 				 "%s%s", XATTR_MAC_OSX_PREFIX, xattr_name);
410 	else
411 		len = strscpy(buffer, xattr_name, name_len + 1);
412 
413 	/* include NUL-byte in length for non-empty name */
414 	if (len >= 0)
415 		len++;
416 	return len;
417 }
418 
419 int hfsplus_setxattr(struct inode *inode, const char *name,
420 		     const void *value, size_t size, int flags,
421 		     const char *prefix, size_t prefixlen)
422 {
423 	char *xattr_name;
424 	int res;
425 
426 	xattr_name = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN + 1,
427 		GFP_KERNEL);
428 	if (!xattr_name)
429 		return -ENOMEM;
430 	strcpy(xattr_name, prefix);
431 	strcpy(xattr_name + prefixlen, name);
432 	res = __hfsplus_setxattr(inode, xattr_name, value, size, flags);
433 	kfree(xattr_name);
434 	return res;
435 }
436 
437 static ssize_t hfsplus_getxattr_finder_info(struct inode *inode,
438 						void *value, size_t size)
439 {
440 	ssize_t res = 0;
441 	struct hfs_find_data fd;
442 	u16 entry_type;
443 	u16 folder_rec_len = sizeof(struct DInfo) + sizeof(struct DXInfo);
444 	u16 file_rec_len = sizeof(struct FInfo) + sizeof(struct FXInfo);
445 	u16 record_len = max(folder_rec_len, file_rec_len);
446 	u8 folder_finder_info[sizeof(struct DInfo) + sizeof(struct DXInfo)];
447 	u8 file_finder_info[sizeof(struct FInfo) + sizeof(struct FXInfo)];
448 
449 	if (size >= record_len) {
450 		res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &fd);
451 		if (res) {
452 			pr_err("can't init xattr find struct\n");
453 			return res;
454 		}
455 		res = hfsplus_find_cat(inode->i_sb, inode->i_ino, &fd);
456 		if (res)
457 			goto end_getxattr_finder_info;
458 		entry_type = hfs_bnode_read_u16(fd.bnode, fd.entryoffset);
459 
460 		if (entry_type == HFSPLUS_FOLDER) {
461 			hfs_bnode_read(fd.bnode, folder_finder_info,
462 				fd.entryoffset +
463 				offsetof(struct hfsplus_cat_folder, user_info),
464 				folder_rec_len);
465 			memcpy(value, folder_finder_info, folder_rec_len);
466 			res = folder_rec_len;
467 		} else if (entry_type == HFSPLUS_FILE) {
468 			hfs_bnode_read(fd.bnode, file_finder_info,
469 				fd.entryoffset +
470 				offsetof(struct hfsplus_cat_file, user_info),
471 				file_rec_len);
472 			memcpy(value, file_finder_info, file_rec_len);
473 			res = file_rec_len;
474 		} else {
475 			res = -EOPNOTSUPP;
476 			goto end_getxattr_finder_info;
477 		}
478 	} else
479 		res = size ? -ERANGE : record_len;
480 
481 end_getxattr_finder_info:
482 	if (size >= record_len)
483 		hfs_find_exit(&fd);
484 	return res;
485 }
486 
487 ssize_t __hfsplus_getxattr(struct inode *inode, const char *name,
488 			 void *value, size_t size)
489 {
490 	struct hfs_find_data fd;
491 	hfsplus_attr_entry *entry;
492 	__be32 xattr_record_type;
493 	u32 record_type;
494 	u16 record_length = 0;
495 	ssize_t res;
496 
497 	if ((!S_ISREG(inode->i_mode) &&
498 			!S_ISDIR(inode->i_mode)) ||
499 				HFSPLUS_IS_RSRC(inode))
500 		return -EOPNOTSUPP;
501 
502 	if (!strcmp_xattr_finder_info(name))
503 		return hfsplus_getxattr_finder_info(inode, value, size);
504 
505 	if (!HFSPLUS_SB(inode->i_sb)->attr_tree)
506 		return -EOPNOTSUPP;
507 
508 	entry = hfsplus_alloc_attr_entry();
509 	if (!entry) {
510 		pr_err("can't allocate xattr entry\n");
511 		return -ENOMEM;
512 	}
513 
514 	res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->attr_tree, &fd);
515 	if (res) {
516 		pr_err("can't init xattr find struct\n");
517 		goto failed_getxattr_init;
518 	}
519 
520 	res = hfsplus_find_attr(inode->i_sb, inode->i_ino, name, &fd);
521 	if (res) {
522 		if (res == -ENOENT)
523 			res = -ENODATA;
524 		else
525 			pr_err("xattr searching failed\n");
526 		goto out;
527 	}
528 
529 	hfs_bnode_read(fd.bnode, &xattr_record_type,
530 			fd.entryoffset, sizeof(xattr_record_type));
531 	record_type = be32_to_cpu(xattr_record_type);
532 	if (record_type == HFSPLUS_ATTR_INLINE_DATA) {
533 		record_length = hfs_bnode_read_u16(fd.bnode,
534 				fd.entryoffset +
535 				offsetof(struct hfsplus_attr_inline_data,
536 				length));
537 		if (record_length > HFSPLUS_MAX_INLINE_DATA_SIZE) {
538 			pr_err("invalid xattr record size\n");
539 			res = -EIO;
540 			goto out;
541 		}
542 	} else if (record_type == HFSPLUS_ATTR_FORK_DATA ||
543 			record_type == HFSPLUS_ATTR_EXTENTS) {
544 		pr_err("only inline data xattr are supported\n");
545 		res = -EOPNOTSUPP;
546 		goto out;
547 	} else {
548 		pr_err("invalid xattr record\n");
549 		res = -EIO;
550 		goto out;
551 	}
552 
553 	if (size) {
554 		hfs_bnode_read(fd.bnode, entry, fd.entryoffset,
555 				offsetof(struct hfsplus_attr_inline_data,
556 					raw_bytes) + record_length);
557 	}
558 
559 	if (size >= record_length) {
560 		memcpy(value, entry->inline_data.raw_bytes, record_length);
561 		res = record_length;
562 	} else
563 		res = size ? -ERANGE : record_length;
564 
565 out:
566 	hfs_find_exit(&fd);
567 
568 failed_getxattr_init:
569 	hfsplus_destroy_attr_entry(entry);
570 	return res;
571 }
572 
573 ssize_t hfsplus_getxattr(struct inode *inode, const char *name,
574 			 void *value, size_t size,
575 			 const char *prefix, size_t prefixlen)
576 {
577 	int res;
578 	char *xattr_name;
579 
580 	xattr_name = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN + 1,
581 			     GFP_KERNEL);
582 	if (!xattr_name)
583 		return -ENOMEM;
584 
585 	strcpy(xattr_name, prefix);
586 	strcpy(xattr_name + prefixlen, name);
587 
588 	res = __hfsplus_getxattr(inode, xattr_name, value, size);
589 	kfree(xattr_name);
590 	return res;
591 
592 }
593 
594 static inline int can_list(const char *xattr_name)
595 {
596 	if (!xattr_name)
597 		return 0;
598 
599 	return strncmp(xattr_name, XATTR_TRUSTED_PREFIX,
600 			XATTR_TRUSTED_PREFIX_LEN) ||
601 				capable(CAP_SYS_ADMIN);
602 }
603 
604 static ssize_t hfsplus_listxattr_finder_info(struct dentry *dentry,
605 						char *buffer, size_t size)
606 {
607 	ssize_t res;
608 	struct inode *inode = d_inode(dentry);
609 	struct hfs_find_data fd;
610 	u16 entry_type;
611 	u8 folder_finder_info[sizeof(struct DInfo) + sizeof(struct DXInfo)];
612 	u8 file_finder_info[sizeof(struct FInfo) + sizeof(struct FXInfo)];
613 	unsigned long len, found_bit;
614 	int xattr_name_len, symbols_count;
615 
616 	res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &fd);
617 	if (res) {
618 		pr_err("can't init xattr find struct\n");
619 		return res;
620 	}
621 
622 	res = hfsplus_find_cat(inode->i_sb, inode->i_ino, &fd);
623 	if (res)
624 		goto end_listxattr_finder_info;
625 
626 	entry_type = hfs_bnode_read_u16(fd.bnode, fd.entryoffset);
627 	if (entry_type == HFSPLUS_FOLDER) {
628 		len = sizeof(struct DInfo) + sizeof(struct DXInfo);
629 		hfs_bnode_read(fd.bnode, folder_finder_info,
630 				fd.entryoffset +
631 				offsetof(struct hfsplus_cat_folder, user_info),
632 				len);
633 		found_bit = find_first_bit((void *)folder_finder_info, len*8);
634 	} else if (entry_type == HFSPLUS_FILE) {
635 		len = sizeof(struct FInfo) + sizeof(struct FXInfo);
636 		hfs_bnode_read(fd.bnode, file_finder_info,
637 				fd.entryoffset +
638 				offsetof(struct hfsplus_cat_file, user_info),
639 				len);
640 		found_bit = find_first_bit((void *)file_finder_info, len*8);
641 	} else {
642 		res = -EOPNOTSUPP;
643 		goto end_listxattr_finder_info;
644 	}
645 
646 	if (found_bit >= (len*8))
647 		res = 0;
648 	else {
649 		symbols_count = sizeof(HFSPLUS_XATTR_FINDER_INFO_NAME) - 1;
650 		xattr_name_len =
651 			name_len(HFSPLUS_XATTR_FINDER_INFO_NAME, symbols_count);
652 		if (!buffer || !size) {
653 			if (can_list(HFSPLUS_XATTR_FINDER_INFO_NAME))
654 				res = xattr_name_len;
655 		} else if (can_list(HFSPLUS_XATTR_FINDER_INFO_NAME)) {
656 			if (size < xattr_name_len)
657 				res = -ERANGE;
658 			else {
659 				res = copy_name(buffer,
660 						HFSPLUS_XATTR_FINDER_INFO_NAME,
661 						symbols_count);
662 			}
663 		}
664 	}
665 
666 end_listxattr_finder_info:
667 	hfs_find_exit(&fd);
668 
669 	return res;
670 }
671 
672 ssize_t hfsplus_listxattr(struct dentry *dentry, char *buffer, size_t size)
673 {
674 	ssize_t err;
675 	ssize_t res;
676 	struct inode *inode = d_inode(dentry);
677 	struct hfs_find_data fd;
678 	struct hfsplus_attr_key attr_key;
679 	char *strbuf;
680 	int xattr_name_len;
681 
682 	if ((!S_ISREG(inode->i_mode) &&
683 			!S_ISDIR(inode->i_mode)) ||
684 				HFSPLUS_IS_RSRC(inode))
685 		return -EOPNOTSUPP;
686 
687 	res = hfsplus_listxattr_finder_info(dentry, buffer, size);
688 	if (res < 0)
689 		return res;
690 	else if (!HFSPLUS_SB(inode->i_sb)->attr_tree)
691 		return (res == 0) ? -EOPNOTSUPP : res;
692 
693 	err = hfs_find_init(HFSPLUS_SB(inode->i_sb)->attr_tree, &fd);
694 	if (err) {
695 		pr_err("can't init xattr find struct\n");
696 		return err;
697 	}
698 
699 	strbuf = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN +
700 			XATTR_MAC_OSX_PREFIX_LEN + 1, GFP_KERNEL);
701 	if (!strbuf) {
702 		res = -ENOMEM;
703 		goto out;
704 	}
705 
706 	err = hfsplus_find_attr(inode->i_sb, inode->i_ino, NULL, &fd);
707 	if (err) {
708 		if (err == -ENOENT) {
709 			if (res == 0)
710 				res = -ENODATA;
711 			goto end_listxattr;
712 		} else {
713 			res = err;
714 			goto end_listxattr;
715 		}
716 	}
717 
718 	for (;;) {
719 		u16 key_len = hfs_bnode_read_u16(fd.bnode, fd.keyoffset);
720 
721 		if (key_len == 0 || key_len > fd.tree->max_key_len) {
722 			pr_err("invalid xattr key length: %d\n", key_len);
723 			res = -EIO;
724 			goto end_listxattr;
725 		}
726 
727 		hfs_bnode_read(fd.bnode, &attr_key,
728 				fd.keyoffset, key_len + sizeof(key_len));
729 
730 		if (be32_to_cpu(attr_key.cnid) != inode->i_ino)
731 			goto end_listxattr;
732 
733 		xattr_name_len = NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN;
734 		if (hfsplus_uni2asc(inode->i_sb,
735 			(const struct hfsplus_unistr *)&fd.key->attr.key_name,
736 					strbuf, &xattr_name_len)) {
737 			pr_err("unicode conversion failed\n");
738 			res = -EIO;
739 			goto end_listxattr;
740 		}
741 
742 		if (!buffer || !size) {
743 			if (can_list(strbuf))
744 				res += name_len(strbuf, xattr_name_len);
745 		} else if (can_list(strbuf)) {
746 			if (size < (res + name_len(strbuf, xattr_name_len))) {
747 				res = -ERANGE;
748 				goto end_listxattr;
749 			} else
750 				res += copy_name(buffer + res,
751 						strbuf, xattr_name_len);
752 		}
753 
754 		if (hfs_brec_goto(&fd, 1))
755 			goto end_listxattr;
756 	}
757 
758 end_listxattr:
759 	kfree(strbuf);
760 out:
761 	hfs_find_exit(&fd);
762 	return res;
763 }
764 
765 static int hfsplus_removexattr(struct inode *inode, const char *name)
766 {
767 	int err;
768 	struct hfs_find_data cat_fd;
769 	u16 flags;
770 	u16 cat_entry_type;
771 	int is_xattr_acl_deleted;
772 	int is_all_xattrs_deleted;
773 
774 	if (!HFSPLUS_SB(inode->i_sb)->attr_tree)
775 		return -EOPNOTSUPP;
776 
777 	if (!strcmp_xattr_finder_info(name))
778 		return -EOPNOTSUPP;
779 
780 	err = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &cat_fd);
781 	if (err) {
782 		pr_err("can't init xattr find struct\n");
783 		return err;
784 	}
785 
786 	err = hfsplus_find_cat(inode->i_sb, inode->i_ino, &cat_fd);
787 	if (err) {
788 		pr_err("catalog searching failed\n");
789 		goto end_removexattr;
790 	}
791 
792 	err = hfsplus_delete_attr(inode, name);
793 	if (err)
794 		goto end_removexattr;
795 
796 	is_xattr_acl_deleted = !strcmp_xattr_acl(name);
797 	is_all_xattrs_deleted = !hfsplus_attr_exists(inode, NULL);
798 
799 	if (!is_xattr_acl_deleted && !is_all_xattrs_deleted)
800 		goto end_removexattr;
801 
802 	cat_entry_type = hfs_bnode_read_u16(cat_fd.bnode, cat_fd.entryoffset);
803 
804 	if (cat_entry_type == HFSPLUS_FOLDER) {
805 		flags = hfs_bnode_read_u16(cat_fd.bnode, cat_fd.entryoffset +
806 				offsetof(struct hfsplus_cat_folder, flags));
807 		if (is_xattr_acl_deleted)
808 			flags &= ~HFSPLUS_ACL_EXISTS;
809 		if (is_all_xattrs_deleted)
810 			flags &= ~HFSPLUS_XATTR_EXISTS;
811 		hfs_bnode_write_u16(cat_fd.bnode, cat_fd.entryoffset +
812 				offsetof(struct hfsplus_cat_folder, flags),
813 				flags);
814 		hfsplus_mark_inode_dirty(inode, HFSPLUS_I_CAT_DIRTY);
815 	} else if (cat_entry_type == HFSPLUS_FILE) {
816 		flags = hfs_bnode_read_u16(cat_fd.bnode, cat_fd.entryoffset +
817 				offsetof(struct hfsplus_cat_file, flags));
818 		if (is_xattr_acl_deleted)
819 			flags &= ~HFSPLUS_ACL_EXISTS;
820 		if (is_all_xattrs_deleted)
821 			flags &= ~HFSPLUS_XATTR_EXISTS;
822 		hfs_bnode_write_u16(cat_fd.bnode, cat_fd.entryoffset +
823 				offsetof(struct hfsplus_cat_file, flags),
824 				flags);
825 		hfsplus_mark_inode_dirty(inode, HFSPLUS_I_CAT_DIRTY);
826 	} else {
827 		pr_err("invalid catalog entry type\n");
828 		err = -EIO;
829 		goto end_removexattr;
830 	}
831 
832 end_removexattr:
833 	hfs_find_exit(&cat_fd);
834 	return err;
835 }
836 
837 static int hfsplus_osx_getxattr(const struct xattr_handler *handler,
838 				struct dentry *unused, struct inode *inode,
839 				const char *name, void *buffer, size_t size)
840 {
841 	/*
842 	 * Don't allow retrieving properly prefixed attributes
843 	 * by prepending them with "osx."
844 	 */
845 	if (is_known_namespace(name))
846 		return -EOPNOTSUPP;
847 
848 	/*
849 	 * osx is the namespace we use to indicate an unprefixed
850 	 * attribute on the filesystem (like the ones that OS X
851 	 * creates), so we pass the name through unmodified (after
852 	 * ensuring it doesn't conflict with another namespace).
853 	 */
854 	return __hfsplus_getxattr(inode, name, buffer, size);
855 }
856 
857 static int hfsplus_osx_setxattr(const struct xattr_handler *handler,
858 				struct mnt_idmap *idmap,
859 				struct dentry *unused, struct inode *inode,
860 				const char *name, const void *buffer,
861 				size_t size, int flags)
862 {
863 	/*
864 	 * Don't allow setting properly prefixed attributes
865 	 * by prepending them with "osx."
866 	 */
867 	if (is_known_namespace(name))
868 		return -EOPNOTSUPP;
869 
870 	/*
871 	 * osx is the namespace we use to indicate an unprefixed
872 	 * attribute on the filesystem (like the ones that OS X
873 	 * creates), so we pass the name through unmodified (after
874 	 * ensuring it doesn't conflict with another namespace).
875 	 */
876 	return __hfsplus_setxattr(inode, name, buffer, size, flags);
877 }
878 
879 const struct xattr_handler hfsplus_xattr_osx_handler = {
880 	.prefix	= XATTR_MAC_OSX_PREFIX,
881 	.get	= hfsplus_osx_getxattr,
882 	.set	= hfsplus_osx_setxattr,
883 };
884