xref: /openbmc/linux/fs/hfsplus/xattr.c (revision 2cf1c348)
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 *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 = 0;
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 int copy_name(char *buffer, const char *xattr_name, int name_len)
404 {
405 	int len = name_len;
406 	int offset = 0;
407 
408 	if (!is_known_namespace(xattr_name)) {
409 		memcpy(buffer, XATTR_MAC_OSX_PREFIX, XATTR_MAC_OSX_PREFIX_LEN);
410 		offset += XATTR_MAC_OSX_PREFIX_LEN;
411 		len += XATTR_MAC_OSX_PREFIX_LEN;
412 	}
413 
414 	strncpy(buffer + offset, xattr_name, name_len);
415 	memset(buffer + offset + name_len, 0, 1);
416 	len += 1;
417 
418 	return len;
419 }
420 
421 int hfsplus_setxattr(struct inode *inode, const char *name,
422 		     const void *value, size_t size, int flags,
423 		     const char *prefix, size_t prefixlen)
424 {
425 	char *xattr_name;
426 	int res;
427 
428 	xattr_name = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN + 1,
429 		GFP_KERNEL);
430 	if (!xattr_name)
431 		return -ENOMEM;
432 	strcpy(xattr_name, prefix);
433 	strcpy(xattr_name + prefixlen, name);
434 	res = __hfsplus_setxattr(inode, xattr_name, value, size, flags);
435 	kfree(xattr_name);
436 	return res;
437 }
438 
439 static ssize_t hfsplus_getxattr_finder_info(struct inode *inode,
440 						void *value, size_t size)
441 {
442 	ssize_t res = 0;
443 	struct hfs_find_data fd;
444 	u16 entry_type;
445 	u16 folder_rec_len = sizeof(struct DInfo) + sizeof(struct DXInfo);
446 	u16 file_rec_len = sizeof(struct FInfo) + sizeof(struct FXInfo);
447 	u16 record_len = max(folder_rec_len, file_rec_len);
448 	u8 folder_finder_info[sizeof(struct DInfo) + sizeof(struct DXInfo)];
449 	u8 file_finder_info[sizeof(struct FInfo) + sizeof(struct FXInfo)];
450 
451 	if (size >= record_len) {
452 		res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &fd);
453 		if (res) {
454 			pr_err("can't init xattr find struct\n");
455 			return res;
456 		}
457 		res = hfsplus_find_cat(inode->i_sb, inode->i_ino, &fd);
458 		if (res)
459 			goto end_getxattr_finder_info;
460 		entry_type = hfs_bnode_read_u16(fd.bnode, fd.entryoffset);
461 
462 		if (entry_type == HFSPLUS_FOLDER) {
463 			hfs_bnode_read(fd.bnode, folder_finder_info,
464 				fd.entryoffset +
465 				offsetof(struct hfsplus_cat_folder, user_info),
466 				folder_rec_len);
467 			memcpy(value, folder_finder_info, folder_rec_len);
468 			res = folder_rec_len;
469 		} else if (entry_type == HFSPLUS_FILE) {
470 			hfs_bnode_read(fd.bnode, file_finder_info,
471 				fd.entryoffset +
472 				offsetof(struct hfsplus_cat_file, user_info),
473 				file_rec_len);
474 			memcpy(value, file_finder_info, file_rec_len);
475 			res = file_rec_len;
476 		} else {
477 			res = -EOPNOTSUPP;
478 			goto end_getxattr_finder_info;
479 		}
480 	} else
481 		res = size ? -ERANGE : record_len;
482 
483 end_getxattr_finder_info:
484 	if (size >= record_len)
485 		hfs_find_exit(&fd);
486 	return res;
487 }
488 
489 ssize_t __hfsplus_getxattr(struct inode *inode, const char *name,
490 			 void *value, size_t size)
491 {
492 	struct hfs_find_data fd;
493 	hfsplus_attr_entry *entry;
494 	__be32 xattr_record_type;
495 	u32 record_type;
496 	u16 record_length = 0;
497 	ssize_t res = 0;
498 
499 	if ((!S_ISREG(inode->i_mode) &&
500 			!S_ISDIR(inode->i_mode)) ||
501 				HFSPLUS_IS_RSRC(inode))
502 		return -EOPNOTSUPP;
503 
504 	if (!strcmp_xattr_finder_info(name))
505 		return hfsplus_getxattr_finder_info(inode, value, size);
506 
507 	if (!HFSPLUS_SB(inode->i_sb)->attr_tree)
508 		return -EOPNOTSUPP;
509 
510 	entry = hfsplus_alloc_attr_entry();
511 	if (!entry) {
512 		pr_err("can't allocate xattr entry\n");
513 		return -ENOMEM;
514 	}
515 
516 	res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->attr_tree, &fd);
517 	if (res) {
518 		pr_err("can't init xattr find struct\n");
519 		goto failed_getxattr_init;
520 	}
521 
522 	res = hfsplus_find_attr(inode->i_sb, inode->i_ino, name, &fd);
523 	if (res) {
524 		if (res == -ENOENT)
525 			res = -ENODATA;
526 		else
527 			pr_err("xattr searching failed\n");
528 		goto out;
529 	}
530 
531 	hfs_bnode_read(fd.bnode, &xattr_record_type,
532 			fd.entryoffset, sizeof(xattr_record_type));
533 	record_type = be32_to_cpu(xattr_record_type);
534 	if (record_type == HFSPLUS_ATTR_INLINE_DATA) {
535 		record_length = hfs_bnode_read_u16(fd.bnode,
536 				fd.entryoffset +
537 				offsetof(struct hfsplus_attr_inline_data,
538 				length));
539 		if (record_length > HFSPLUS_MAX_INLINE_DATA_SIZE) {
540 			pr_err("invalid xattr record size\n");
541 			res = -EIO;
542 			goto out;
543 		}
544 	} else if (record_type == HFSPLUS_ATTR_FORK_DATA ||
545 			record_type == HFSPLUS_ATTR_EXTENTS) {
546 		pr_err("only inline data xattr are supported\n");
547 		res = -EOPNOTSUPP;
548 		goto out;
549 	} else {
550 		pr_err("invalid xattr record\n");
551 		res = -EIO;
552 		goto out;
553 	}
554 
555 	if (size) {
556 		hfs_bnode_read(fd.bnode, entry, fd.entryoffset,
557 				offsetof(struct hfsplus_attr_inline_data,
558 					raw_bytes) + record_length);
559 	}
560 
561 	if (size >= record_length) {
562 		memcpy(value, entry->inline_data.raw_bytes, record_length);
563 		res = record_length;
564 	} else
565 		res = size ? -ERANGE : record_length;
566 
567 out:
568 	hfs_find_exit(&fd);
569 
570 failed_getxattr_init:
571 	hfsplus_destroy_attr_entry(entry);
572 	return res;
573 }
574 
575 ssize_t hfsplus_getxattr(struct inode *inode, const char *name,
576 			 void *value, size_t size,
577 			 const char *prefix, size_t prefixlen)
578 {
579 	int res;
580 	char *xattr_name;
581 
582 	xattr_name = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN + 1,
583 			     GFP_KERNEL);
584 	if (!xattr_name)
585 		return -ENOMEM;
586 
587 	strcpy(xattr_name, prefix);
588 	strcpy(xattr_name + prefixlen, name);
589 
590 	res = __hfsplus_getxattr(inode, xattr_name, value, size);
591 	kfree(xattr_name);
592 	return res;
593 
594 }
595 
596 static inline int can_list(const char *xattr_name)
597 {
598 	if (!xattr_name)
599 		return 0;
600 
601 	return strncmp(xattr_name, XATTR_TRUSTED_PREFIX,
602 			XATTR_TRUSTED_PREFIX_LEN) ||
603 				capable(CAP_SYS_ADMIN);
604 }
605 
606 static ssize_t hfsplus_listxattr_finder_info(struct dentry *dentry,
607 						char *buffer, size_t size)
608 {
609 	ssize_t res = 0;
610 	struct inode *inode = d_inode(dentry);
611 	struct hfs_find_data fd;
612 	u16 entry_type;
613 	u8 folder_finder_info[sizeof(struct DInfo) + sizeof(struct DXInfo)];
614 	u8 file_finder_info[sizeof(struct FInfo) + sizeof(struct FXInfo)];
615 	unsigned long len, found_bit;
616 	int xattr_name_len, symbols_count;
617 
618 	res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &fd);
619 	if (res) {
620 		pr_err("can't init xattr find struct\n");
621 		return res;
622 	}
623 
624 	res = hfsplus_find_cat(inode->i_sb, inode->i_ino, &fd);
625 	if (res)
626 		goto end_listxattr_finder_info;
627 
628 	entry_type = hfs_bnode_read_u16(fd.bnode, fd.entryoffset);
629 	if (entry_type == HFSPLUS_FOLDER) {
630 		len = sizeof(struct DInfo) + sizeof(struct DXInfo);
631 		hfs_bnode_read(fd.bnode, folder_finder_info,
632 				fd.entryoffset +
633 				offsetof(struct hfsplus_cat_folder, user_info),
634 				len);
635 		found_bit = find_first_bit((void *)folder_finder_info, len*8);
636 	} else if (entry_type == HFSPLUS_FILE) {
637 		len = sizeof(struct FInfo) + sizeof(struct FXInfo);
638 		hfs_bnode_read(fd.bnode, file_finder_info,
639 				fd.entryoffset +
640 				offsetof(struct hfsplus_cat_file, user_info),
641 				len);
642 		found_bit = find_first_bit((void *)file_finder_info, len*8);
643 	} else {
644 		res = -EOPNOTSUPP;
645 		goto end_listxattr_finder_info;
646 	}
647 
648 	if (found_bit >= (len*8))
649 		res = 0;
650 	else {
651 		symbols_count = sizeof(HFSPLUS_XATTR_FINDER_INFO_NAME) - 1;
652 		xattr_name_len =
653 			name_len(HFSPLUS_XATTR_FINDER_INFO_NAME, symbols_count);
654 		if (!buffer || !size) {
655 			if (can_list(HFSPLUS_XATTR_FINDER_INFO_NAME))
656 				res = xattr_name_len;
657 		} else if (can_list(HFSPLUS_XATTR_FINDER_INFO_NAME)) {
658 			if (size < xattr_name_len)
659 				res = -ERANGE;
660 			else {
661 				res = copy_name(buffer,
662 						HFSPLUS_XATTR_FINDER_INFO_NAME,
663 						symbols_count);
664 			}
665 		}
666 	}
667 
668 end_listxattr_finder_info:
669 	hfs_find_exit(&fd);
670 
671 	return res;
672 }
673 
674 ssize_t hfsplus_listxattr(struct dentry *dentry, char *buffer, size_t size)
675 {
676 	ssize_t err;
677 	ssize_t res = 0;
678 	struct inode *inode = d_inode(dentry);
679 	struct hfs_find_data fd;
680 	u16 key_len = 0;
681 	struct hfsplus_attr_key attr_key;
682 	char *strbuf;
683 	int xattr_name_len;
684 
685 	if ((!S_ISREG(inode->i_mode) &&
686 			!S_ISDIR(inode->i_mode)) ||
687 				HFSPLUS_IS_RSRC(inode))
688 		return -EOPNOTSUPP;
689 
690 	res = hfsplus_listxattr_finder_info(dentry, buffer, size);
691 	if (res < 0)
692 		return res;
693 	else if (!HFSPLUS_SB(inode->i_sb)->attr_tree)
694 		return (res == 0) ? -EOPNOTSUPP : res;
695 
696 	err = hfs_find_init(HFSPLUS_SB(inode->i_sb)->attr_tree, &fd);
697 	if (err) {
698 		pr_err("can't init xattr find struct\n");
699 		return err;
700 	}
701 
702 	strbuf = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN +
703 			XATTR_MAC_OSX_PREFIX_LEN + 1, GFP_KERNEL);
704 	if (!strbuf) {
705 		res = -ENOMEM;
706 		goto out;
707 	}
708 
709 	err = hfsplus_find_attr(inode->i_sb, inode->i_ino, NULL, &fd);
710 	if (err) {
711 		if (err == -ENOENT) {
712 			if (res == 0)
713 				res = -ENODATA;
714 			goto end_listxattr;
715 		} else {
716 			res = err;
717 			goto end_listxattr;
718 		}
719 	}
720 
721 	for (;;) {
722 		key_len = hfs_bnode_read_u16(fd.bnode, fd.keyoffset);
723 		if (key_len == 0 || key_len > fd.tree->max_key_len) {
724 			pr_err("invalid xattr key length: %d\n", key_len);
725 			res = -EIO;
726 			goto end_listxattr;
727 		}
728 
729 		hfs_bnode_read(fd.bnode, &attr_key,
730 				fd.keyoffset, key_len + sizeof(key_len));
731 
732 		if (be32_to_cpu(attr_key.cnid) != inode->i_ino)
733 			goto end_listxattr;
734 
735 		xattr_name_len = NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN;
736 		if (hfsplus_uni2asc(inode->i_sb,
737 			(const struct hfsplus_unistr *)&fd.key->attr.key_name,
738 					strbuf, &xattr_name_len)) {
739 			pr_err("unicode conversion failed\n");
740 			res = -EIO;
741 			goto end_listxattr;
742 		}
743 
744 		if (!buffer || !size) {
745 			if (can_list(strbuf))
746 				res += name_len(strbuf, xattr_name_len);
747 		} else if (can_list(strbuf)) {
748 			if (size < (res + name_len(strbuf, xattr_name_len))) {
749 				res = -ERANGE;
750 				goto end_listxattr;
751 			} else
752 				res += copy_name(buffer + res,
753 						strbuf, xattr_name_len);
754 		}
755 
756 		if (hfs_brec_goto(&fd, 1))
757 			goto end_listxattr;
758 	}
759 
760 end_listxattr:
761 	kfree(strbuf);
762 out:
763 	hfs_find_exit(&fd);
764 	return res;
765 }
766 
767 static int hfsplus_removexattr(struct inode *inode, const char *name)
768 {
769 	int err = 0;
770 	struct hfs_find_data cat_fd;
771 	u16 flags;
772 	u16 cat_entry_type;
773 	int is_xattr_acl_deleted = 0;
774 	int is_all_xattrs_deleted = 0;
775 
776 	if (!HFSPLUS_SB(inode->i_sb)->attr_tree)
777 		return -EOPNOTSUPP;
778 
779 	if (!strcmp_xattr_finder_info(name))
780 		return -EOPNOTSUPP;
781 
782 	err = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &cat_fd);
783 	if (err) {
784 		pr_err("can't init xattr find struct\n");
785 		return err;
786 	}
787 
788 	err = hfsplus_find_cat(inode->i_sb, inode->i_ino, &cat_fd);
789 	if (err) {
790 		pr_err("catalog searching failed\n");
791 		goto end_removexattr;
792 	}
793 
794 	err = hfsplus_delete_attr(inode, name);
795 	if (err)
796 		goto end_removexattr;
797 
798 	is_xattr_acl_deleted = !strcmp_xattr_acl(name);
799 	is_all_xattrs_deleted = !hfsplus_attr_exists(inode, NULL);
800 
801 	if (!is_xattr_acl_deleted && !is_all_xattrs_deleted)
802 		goto end_removexattr;
803 
804 	cat_entry_type = hfs_bnode_read_u16(cat_fd.bnode, cat_fd.entryoffset);
805 
806 	if (cat_entry_type == HFSPLUS_FOLDER) {
807 		flags = hfs_bnode_read_u16(cat_fd.bnode, cat_fd.entryoffset +
808 				offsetof(struct hfsplus_cat_folder, flags));
809 		if (is_xattr_acl_deleted)
810 			flags &= ~HFSPLUS_ACL_EXISTS;
811 		if (is_all_xattrs_deleted)
812 			flags &= ~HFSPLUS_XATTR_EXISTS;
813 		hfs_bnode_write_u16(cat_fd.bnode, cat_fd.entryoffset +
814 				offsetof(struct hfsplus_cat_folder, flags),
815 				flags);
816 		hfsplus_mark_inode_dirty(inode, HFSPLUS_I_CAT_DIRTY);
817 	} else if (cat_entry_type == HFSPLUS_FILE) {
818 		flags = hfs_bnode_read_u16(cat_fd.bnode, cat_fd.entryoffset +
819 				offsetof(struct hfsplus_cat_file, flags));
820 		if (is_xattr_acl_deleted)
821 			flags &= ~HFSPLUS_ACL_EXISTS;
822 		if (is_all_xattrs_deleted)
823 			flags &= ~HFSPLUS_XATTR_EXISTS;
824 		hfs_bnode_write_u16(cat_fd.bnode, cat_fd.entryoffset +
825 				offsetof(struct hfsplus_cat_file, flags),
826 				flags);
827 		hfsplus_mark_inode_dirty(inode, HFSPLUS_I_CAT_DIRTY);
828 	} else {
829 		pr_err("invalid catalog entry type\n");
830 		err = -EIO;
831 		goto end_removexattr;
832 	}
833 
834 end_removexattr:
835 	hfs_find_exit(&cat_fd);
836 	return err;
837 }
838 
839 static int hfsplus_osx_getxattr(const struct xattr_handler *handler,
840 				struct dentry *unused, struct inode *inode,
841 				const char *name, void *buffer, size_t size)
842 {
843 	/*
844 	 * Don't allow retrieving properly prefixed attributes
845 	 * by prepending them with "osx."
846 	 */
847 	if (is_known_namespace(name))
848 		return -EOPNOTSUPP;
849 
850 	/*
851 	 * osx is the namespace we use to indicate an unprefixed
852 	 * attribute on the filesystem (like the ones that OS X
853 	 * creates), so we pass the name through unmodified (after
854 	 * ensuring it doesn't conflict with another namespace).
855 	 */
856 	return __hfsplus_getxattr(inode, name, buffer, size);
857 }
858 
859 static int hfsplus_osx_setxattr(const struct xattr_handler *handler,
860 				struct user_namespace *mnt_userns,
861 				struct dentry *unused, struct inode *inode,
862 				const char *name, const void *buffer,
863 				size_t size, int flags)
864 {
865 	/*
866 	 * Don't allow setting properly prefixed attributes
867 	 * by prepending them with "osx."
868 	 */
869 	if (is_known_namespace(name))
870 		return -EOPNOTSUPP;
871 
872 	/*
873 	 * osx is the namespace we use to indicate an unprefixed
874 	 * attribute on the filesystem (like the ones that OS X
875 	 * creates), so we pass the name through unmodified (after
876 	 * ensuring it doesn't conflict with another namespace).
877 	 */
878 	return __hfsplus_setxattr(inode, name, buffer, size, flags);
879 }
880 
881 const struct xattr_handler hfsplus_xattr_osx_handler = {
882 	.prefix	= XATTR_MAC_OSX_PREFIX,
883 	.get	= hfsplus_osx_getxattr,
884 	.set	= hfsplus_osx_setxattr,
885 };
886