xref: /linux/fs/hfsplus/xattr.c (revision 8c749ce93ee69e789e46b3be98de9e0cbfcf8ed8)
1 /*
2  * linux/fs/hfsplus/xattr.c
3  *
4  * Vyacheslav Dubeyko <slava@dubeyko.com>
5  *
6  * Logic of processing extended attributes
7  */
8 
9 #include "hfsplus_fs.h"
10 #include <linux/posix_acl_xattr.h>
11 #include <linux/nls.h>
12 #include "xattr.h"
13 #include "acl.h"
14 
15 static int hfsplus_removexattr(struct inode *inode, const char *name);
16 
17 const struct xattr_handler *hfsplus_xattr_handlers[] = {
18 	&hfsplus_xattr_osx_handler,
19 	&hfsplus_xattr_user_handler,
20 	&hfsplus_xattr_trusted_handler,
21 #ifdef CONFIG_HFSPLUS_FS_POSIX_ACL
22 	&posix_acl_access_xattr_handler,
23 	&posix_acl_default_xattr_handler,
24 #endif
25 	&hfsplus_xattr_security_handler,
26 	NULL
27 };
28 
29 static int strcmp_xattr_finder_info(const char *name)
30 {
31 	if (name) {
32 		return strncmp(name, HFSPLUS_XATTR_FINDER_INFO_NAME,
33 				sizeof(HFSPLUS_XATTR_FINDER_INFO_NAME));
34 	}
35 	return -1;
36 }
37 
38 static int strcmp_xattr_acl(const char *name)
39 {
40 	if (name) {
41 		return strncmp(name, HFSPLUS_XATTR_ACL_NAME,
42 				sizeof(HFSPLUS_XATTR_ACL_NAME));
43 	}
44 	return -1;
45 }
46 
47 static bool is_known_namespace(const char *name)
48 {
49 	if (strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) &&
50 	    strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN) &&
51 	    strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) &&
52 	    strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN))
53 		return false;
54 
55 	return true;
56 }
57 
58 static void hfsplus_init_header_node(struct inode *attr_file,
59 					u32 clump_size,
60 					char *buf, u16 node_size)
61 {
62 	struct hfs_bnode_desc *desc;
63 	struct hfs_btree_header_rec *head;
64 	u16 offset;
65 	__be16 *rec_offsets;
66 	u32 hdr_node_map_rec_bits;
67 	char *bmp;
68 	u32 used_nodes;
69 	u32 used_bmp_bytes;
70 	u64 tmp;
71 
72 	hfs_dbg(ATTR_MOD, "init_hdr_attr_file: clump %u, node_size %u\n",
73 		clump_size, node_size);
74 
75 	/* The end of the node contains list of record offsets */
76 	rec_offsets = (__be16 *)(buf + node_size);
77 
78 	desc = (struct hfs_bnode_desc *)buf;
79 	desc->type = HFS_NODE_HEADER;
80 	desc->num_recs = cpu_to_be16(HFSPLUS_BTREE_HDR_NODE_RECS_COUNT);
81 	offset = sizeof(struct hfs_bnode_desc);
82 	*--rec_offsets = cpu_to_be16(offset);
83 
84 	head = (struct hfs_btree_header_rec *)(buf + offset);
85 	head->node_size = cpu_to_be16(node_size);
86 	tmp = i_size_read(attr_file);
87 	do_div(tmp, node_size);
88 	head->node_count = cpu_to_be32(tmp);
89 	head->free_nodes = cpu_to_be32(be32_to_cpu(head->node_count) - 1);
90 	head->clump_size = cpu_to_be32(clump_size);
91 	head->attributes |= cpu_to_be32(HFS_TREE_BIGKEYS | HFS_TREE_VARIDXKEYS);
92 	head->max_key_len = cpu_to_be16(HFSPLUS_ATTR_KEYLEN - sizeof(u16));
93 	offset += sizeof(struct hfs_btree_header_rec);
94 	*--rec_offsets = cpu_to_be16(offset);
95 	offset += HFSPLUS_BTREE_HDR_USER_BYTES;
96 	*--rec_offsets = cpu_to_be16(offset);
97 
98 	hdr_node_map_rec_bits = 8 * (node_size - offset - (4 * sizeof(u16)));
99 	if (be32_to_cpu(head->node_count) > hdr_node_map_rec_bits) {
100 		u32 map_node_bits;
101 		u32 map_nodes;
102 
103 		desc->next = cpu_to_be32(be32_to_cpu(head->leaf_tail) + 1);
104 		map_node_bits = 8 * (node_size - sizeof(struct hfs_bnode_desc) -
105 					(2 * sizeof(u16)) - 2);
106 		map_nodes = (be32_to_cpu(head->node_count) -
107 				hdr_node_map_rec_bits +
108 				(map_node_bits - 1)) / map_node_bits;
109 		be32_add_cpu(&head->free_nodes, 0 - map_nodes);
110 	}
111 
112 	bmp = buf + offset;
113 	used_nodes =
114 		be32_to_cpu(head->node_count) - be32_to_cpu(head->free_nodes);
115 	used_bmp_bytes = used_nodes / 8;
116 	if (used_bmp_bytes) {
117 		memset(bmp, 0xFF, used_bmp_bytes);
118 		bmp += used_bmp_bytes;
119 		used_nodes %= 8;
120 	}
121 	*bmp = ~(0xFF >> used_nodes);
122 	offset += hdr_node_map_rec_bits / 8;
123 	*--rec_offsets = cpu_to_be16(offset);
124 }
125 
126 static int hfsplus_create_attributes_file(struct super_block *sb)
127 {
128 	int err = 0;
129 	struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
130 	struct inode *attr_file;
131 	struct hfsplus_inode_info *hip;
132 	u32 clump_size;
133 	u16 node_size = HFSPLUS_ATTR_TREE_NODE_SIZE;
134 	char *buf;
135 	int index, written;
136 	struct address_space *mapping;
137 	struct page *page;
138 	int old_state = HFSPLUS_EMPTY_ATTR_TREE;
139 
140 	hfs_dbg(ATTR_MOD, "create_attr_file: ino %d\n", HFSPLUS_ATTR_CNID);
141 
142 check_attr_tree_state_again:
143 	switch (atomic_read(&sbi->attr_tree_state)) {
144 	case HFSPLUS_EMPTY_ATTR_TREE:
145 		if (old_state != atomic_cmpxchg(&sbi->attr_tree_state,
146 						old_state,
147 						HFSPLUS_CREATING_ATTR_TREE))
148 			goto check_attr_tree_state_again;
149 		break;
150 	case HFSPLUS_CREATING_ATTR_TREE:
151 		/*
152 		 * This state means that another thread is in process
153 		 * of AttributesFile creation. Theoretically, it is
154 		 * possible to be here. But really __setxattr() method
155 		 * first of all calls hfs_find_init() for lookup in
156 		 * B-tree of CatalogFile. This method locks mutex of
157 		 * CatalogFile's B-tree. As a result, if some thread
158 		 * is inside AttributedFile creation operation then
159 		 * another threads will be waiting unlocking of
160 		 * CatalogFile's B-tree's mutex. However, if code will
161 		 * change then we will return error code (-EAGAIN) from
162 		 * here. Really, it means that first try to set of xattr
163 		 * fails with error but second attempt will have success.
164 		 */
165 		return -EAGAIN;
166 	case HFSPLUS_VALID_ATTR_TREE:
167 		return 0;
168 	case HFSPLUS_FAILED_ATTR_TREE:
169 		return -EOPNOTSUPP;
170 	default:
171 		BUG();
172 	}
173 
174 	attr_file = hfsplus_iget(sb, HFSPLUS_ATTR_CNID);
175 	if (IS_ERR(attr_file)) {
176 		pr_err("failed to load attributes file\n");
177 		return PTR_ERR(attr_file);
178 	}
179 
180 	BUG_ON(i_size_read(attr_file) != 0);
181 
182 	hip = HFSPLUS_I(attr_file);
183 
184 	clump_size = hfsplus_calc_btree_clump_size(sb->s_blocksize,
185 						    node_size,
186 						    sbi->sect_count,
187 						    HFSPLUS_ATTR_CNID);
188 
189 	mutex_lock(&hip->extents_lock);
190 	hip->clump_blocks = clump_size >> sbi->alloc_blksz_shift;
191 	mutex_unlock(&hip->extents_lock);
192 
193 	if (sbi->free_blocks <= (hip->clump_blocks << 1)) {
194 		err = -ENOSPC;
195 		goto end_attr_file_creation;
196 	}
197 
198 	while (hip->alloc_blocks < hip->clump_blocks) {
199 		err = hfsplus_file_extend(attr_file, false);
200 		if (unlikely(err)) {
201 			pr_err("failed to extend attributes file\n");
202 			goto end_attr_file_creation;
203 		}
204 		hip->phys_size = attr_file->i_size =
205 			(loff_t)hip->alloc_blocks << sbi->alloc_blksz_shift;
206 		hip->fs_blocks = hip->alloc_blocks << sbi->fs_shift;
207 		inode_set_bytes(attr_file, attr_file->i_size);
208 	}
209 
210 	buf = kzalloc(node_size, GFP_NOFS);
211 	if (!buf) {
212 		pr_err("failed to allocate memory for header node\n");
213 		err = -ENOMEM;
214 		goto end_attr_file_creation;
215 	}
216 
217 	hfsplus_init_header_node(attr_file, clump_size, buf, node_size);
218 
219 	mapping = attr_file->i_mapping;
220 
221 	index = 0;
222 	written = 0;
223 	for (; written < node_size; index++, written += PAGE_CACHE_SIZE) {
224 		void *kaddr;
225 
226 		page = read_mapping_page(mapping, index, NULL);
227 		if (IS_ERR(page)) {
228 			err = PTR_ERR(page);
229 			goto failed_header_node_init;
230 		}
231 
232 		kaddr = kmap_atomic(page);
233 		memcpy(kaddr, buf + written,
234 			min_t(size_t, PAGE_CACHE_SIZE, node_size - written));
235 		kunmap_atomic(kaddr);
236 
237 		set_page_dirty(page);
238 		page_cache_release(page);
239 	}
240 
241 	hfsplus_mark_inode_dirty(attr_file, HFSPLUS_I_ATTR_DIRTY);
242 
243 	sbi->attr_tree = hfs_btree_open(sb, HFSPLUS_ATTR_CNID);
244 	if (!sbi->attr_tree)
245 		pr_err("failed to load attributes file\n");
246 
247 failed_header_node_init:
248 	kfree(buf);
249 
250 end_attr_file_creation:
251 	iput(attr_file);
252 
253 	if (!err)
254 		atomic_set(&sbi->attr_tree_state, HFSPLUS_VALID_ATTR_TREE);
255 	else if (err == -ENOSPC)
256 		atomic_set(&sbi->attr_tree_state, HFSPLUS_EMPTY_ATTR_TREE);
257 	else
258 		atomic_set(&sbi->attr_tree_state, HFSPLUS_FAILED_ATTR_TREE);
259 
260 	return err;
261 }
262 
263 int __hfsplus_setxattr(struct inode *inode, const char *name,
264 			const void *value, size_t size, int flags)
265 {
266 	int err = 0;
267 	struct hfs_find_data cat_fd;
268 	hfsplus_cat_entry entry;
269 	u16 cat_entry_flags, cat_entry_type;
270 	u16 folder_finderinfo_len = sizeof(struct DInfo) +
271 					sizeof(struct DXInfo);
272 	u16 file_finderinfo_len = sizeof(struct FInfo) +
273 					sizeof(struct FXInfo);
274 
275 	if ((!S_ISREG(inode->i_mode) &&
276 			!S_ISDIR(inode->i_mode)) ||
277 				HFSPLUS_IS_RSRC(inode))
278 		return -EOPNOTSUPP;
279 
280 	if (value == NULL)
281 		return hfsplus_removexattr(inode, name);
282 
283 	err = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &cat_fd);
284 	if (err) {
285 		pr_err("can't init xattr find struct\n");
286 		return err;
287 	}
288 
289 	err = hfsplus_find_cat(inode->i_sb, inode->i_ino, &cat_fd);
290 	if (err) {
291 		pr_err("catalog searching failed\n");
292 		goto end_setxattr;
293 	}
294 
295 	if (!strcmp_xattr_finder_info(name)) {
296 		if (flags & XATTR_CREATE) {
297 			pr_err("xattr exists yet\n");
298 			err = -EOPNOTSUPP;
299 			goto end_setxattr;
300 		}
301 		hfs_bnode_read(cat_fd.bnode, &entry, cat_fd.entryoffset,
302 					sizeof(hfsplus_cat_entry));
303 		if (be16_to_cpu(entry.type) == HFSPLUS_FOLDER) {
304 			if (size == folder_finderinfo_len) {
305 				memcpy(&entry.folder.user_info, value,
306 						folder_finderinfo_len);
307 				hfs_bnode_write(cat_fd.bnode, &entry,
308 					cat_fd.entryoffset,
309 					sizeof(struct hfsplus_cat_folder));
310 				hfsplus_mark_inode_dirty(inode,
311 						HFSPLUS_I_CAT_DIRTY);
312 			} else {
313 				err = -ERANGE;
314 				goto end_setxattr;
315 			}
316 		} else if (be16_to_cpu(entry.type) == HFSPLUS_FILE) {
317 			if (size == file_finderinfo_len) {
318 				memcpy(&entry.file.user_info, value,
319 						file_finderinfo_len);
320 				hfs_bnode_write(cat_fd.bnode, &entry,
321 					cat_fd.entryoffset,
322 					sizeof(struct hfsplus_cat_file));
323 				hfsplus_mark_inode_dirty(inode,
324 						HFSPLUS_I_CAT_DIRTY);
325 			} else {
326 				err = -ERANGE;
327 				goto end_setxattr;
328 			}
329 		} else {
330 			err = -EOPNOTSUPP;
331 			goto end_setxattr;
332 		}
333 		goto end_setxattr;
334 	}
335 
336 	if (!HFSPLUS_SB(inode->i_sb)->attr_tree) {
337 		err = hfsplus_create_attributes_file(inode->i_sb);
338 		if (unlikely(err))
339 			goto end_setxattr;
340 	}
341 
342 	if (hfsplus_attr_exists(inode, name)) {
343 		if (flags & XATTR_CREATE) {
344 			pr_err("xattr exists yet\n");
345 			err = -EOPNOTSUPP;
346 			goto end_setxattr;
347 		}
348 		err = hfsplus_delete_attr(inode, name);
349 		if (err)
350 			goto end_setxattr;
351 		err = hfsplus_create_attr(inode, name, value, size);
352 		if (err)
353 			goto end_setxattr;
354 	} else {
355 		if (flags & XATTR_REPLACE) {
356 			pr_err("cannot replace xattr\n");
357 			err = -EOPNOTSUPP;
358 			goto end_setxattr;
359 		}
360 		err = hfsplus_create_attr(inode, name, value, size);
361 		if (err)
362 			goto end_setxattr;
363 	}
364 
365 	cat_entry_type = hfs_bnode_read_u16(cat_fd.bnode, cat_fd.entryoffset);
366 	if (cat_entry_type == HFSPLUS_FOLDER) {
367 		cat_entry_flags = hfs_bnode_read_u16(cat_fd.bnode,
368 				    cat_fd.entryoffset +
369 				    offsetof(struct hfsplus_cat_folder, flags));
370 		cat_entry_flags |= HFSPLUS_XATTR_EXISTS;
371 		if (!strcmp_xattr_acl(name))
372 			cat_entry_flags |= HFSPLUS_ACL_EXISTS;
373 		hfs_bnode_write_u16(cat_fd.bnode, cat_fd.entryoffset +
374 				offsetof(struct hfsplus_cat_folder, flags),
375 				cat_entry_flags);
376 		hfsplus_mark_inode_dirty(inode, HFSPLUS_I_CAT_DIRTY);
377 	} else if (cat_entry_type == HFSPLUS_FILE) {
378 		cat_entry_flags = hfs_bnode_read_u16(cat_fd.bnode,
379 				    cat_fd.entryoffset +
380 				    offsetof(struct hfsplus_cat_file, flags));
381 		cat_entry_flags |= HFSPLUS_XATTR_EXISTS;
382 		if (!strcmp_xattr_acl(name))
383 			cat_entry_flags |= HFSPLUS_ACL_EXISTS;
384 		hfs_bnode_write_u16(cat_fd.bnode, cat_fd.entryoffset +
385 				    offsetof(struct hfsplus_cat_file, flags),
386 				    cat_entry_flags);
387 		hfsplus_mark_inode_dirty(inode, HFSPLUS_I_CAT_DIRTY);
388 	} else {
389 		pr_err("invalid catalog entry type\n");
390 		err = -EIO;
391 		goto end_setxattr;
392 	}
393 
394 end_setxattr:
395 	hfs_find_exit(&cat_fd);
396 	return err;
397 }
398 
399 static int name_len(const char *xattr_name, int xattr_name_len)
400 {
401 	int len = xattr_name_len + 1;
402 
403 	if (!is_known_namespace(xattr_name))
404 		len += XATTR_MAC_OSX_PREFIX_LEN;
405 
406 	return len;
407 }
408 
409 static int copy_name(char *buffer, const char *xattr_name, int name_len)
410 {
411 	int len = name_len;
412 	int offset = 0;
413 
414 	if (!is_known_namespace(xattr_name)) {
415 		strncpy(buffer, XATTR_MAC_OSX_PREFIX, XATTR_MAC_OSX_PREFIX_LEN);
416 		offset += XATTR_MAC_OSX_PREFIX_LEN;
417 		len += XATTR_MAC_OSX_PREFIX_LEN;
418 	}
419 
420 	strncpy(buffer + offset, xattr_name, name_len);
421 	memset(buffer + offset + name_len, 0, 1);
422 	len += 1;
423 
424 	return len;
425 }
426 
427 int hfsplus_setxattr(struct dentry *dentry, const char *name,
428 		     const void *value, size_t size, int flags,
429 		     const char *prefix, size_t prefixlen)
430 {
431 	char *xattr_name;
432 	int res;
433 
434 	xattr_name = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN + 1,
435 		GFP_KERNEL);
436 	if (!xattr_name)
437 		return -ENOMEM;
438 	strcpy(xattr_name, prefix);
439 	strcpy(xattr_name + prefixlen, name);
440 	res = __hfsplus_setxattr(d_inode(dentry), xattr_name, value, size,
441 				 flags);
442 	kfree(xattr_name);
443 	return res;
444 }
445 
446 static ssize_t hfsplus_getxattr_finder_info(struct inode *inode,
447 						void *value, size_t size)
448 {
449 	ssize_t res = 0;
450 	struct hfs_find_data fd;
451 	u16 entry_type;
452 	u16 folder_rec_len = sizeof(struct DInfo) + sizeof(struct DXInfo);
453 	u16 file_rec_len = sizeof(struct FInfo) + sizeof(struct FXInfo);
454 	u16 record_len = max(folder_rec_len, file_rec_len);
455 	u8 folder_finder_info[sizeof(struct DInfo) + sizeof(struct DXInfo)];
456 	u8 file_finder_info[sizeof(struct FInfo) + sizeof(struct FXInfo)];
457 
458 	if (size >= record_len) {
459 		res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &fd);
460 		if (res) {
461 			pr_err("can't init xattr find struct\n");
462 			return res;
463 		}
464 		res = hfsplus_find_cat(inode->i_sb, inode->i_ino, &fd);
465 		if (res)
466 			goto end_getxattr_finder_info;
467 		entry_type = hfs_bnode_read_u16(fd.bnode, fd.entryoffset);
468 
469 		if (entry_type == HFSPLUS_FOLDER) {
470 			hfs_bnode_read(fd.bnode, folder_finder_info,
471 				fd.entryoffset +
472 				offsetof(struct hfsplus_cat_folder, user_info),
473 				folder_rec_len);
474 			memcpy(value, folder_finder_info, folder_rec_len);
475 			res = folder_rec_len;
476 		} else if (entry_type == HFSPLUS_FILE) {
477 			hfs_bnode_read(fd.bnode, file_finder_info,
478 				fd.entryoffset +
479 				offsetof(struct hfsplus_cat_file, user_info),
480 				file_rec_len);
481 			memcpy(value, file_finder_info, file_rec_len);
482 			res = file_rec_len;
483 		} else {
484 			res = -EOPNOTSUPP;
485 			goto end_getxattr_finder_info;
486 		}
487 	} else
488 		res = size ? -ERANGE : record_len;
489 
490 end_getxattr_finder_info:
491 	if (size >= record_len)
492 		hfs_find_exit(&fd);
493 	return res;
494 }
495 
496 ssize_t __hfsplus_getxattr(struct inode *inode, const char *name,
497 			 void *value, size_t size)
498 {
499 	struct hfs_find_data fd;
500 	hfsplus_attr_entry *entry;
501 	__be32 xattr_record_type;
502 	u32 record_type;
503 	u16 record_length = 0;
504 	ssize_t res = 0;
505 
506 	if ((!S_ISREG(inode->i_mode) &&
507 			!S_ISDIR(inode->i_mode)) ||
508 				HFSPLUS_IS_RSRC(inode))
509 		return -EOPNOTSUPP;
510 
511 	if (!strcmp_xattr_finder_info(name))
512 		return hfsplus_getxattr_finder_info(inode, value, size);
513 
514 	if (!HFSPLUS_SB(inode->i_sb)->attr_tree)
515 		return -EOPNOTSUPP;
516 
517 	entry = hfsplus_alloc_attr_entry();
518 	if (!entry) {
519 		pr_err("can't allocate xattr entry\n");
520 		return -ENOMEM;
521 	}
522 
523 	res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->attr_tree, &fd);
524 	if (res) {
525 		pr_err("can't init xattr find struct\n");
526 		goto failed_getxattr_init;
527 	}
528 
529 	res = hfsplus_find_attr(inode->i_sb, inode->i_ino, name, &fd);
530 	if (res) {
531 		if (res == -ENOENT)
532 			res = -ENODATA;
533 		else
534 			pr_err("xattr searching failed\n");
535 		goto out;
536 	}
537 
538 	hfs_bnode_read(fd.bnode, &xattr_record_type,
539 			fd.entryoffset, sizeof(xattr_record_type));
540 	record_type = be32_to_cpu(xattr_record_type);
541 	if (record_type == HFSPLUS_ATTR_INLINE_DATA) {
542 		record_length = hfs_bnode_read_u16(fd.bnode,
543 				fd.entryoffset +
544 				offsetof(struct hfsplus_attr_inline_data,
545 				length));
546 		if (record_length > HFSPLUS_MAX_INLINE_DATA_SIZE) {
547 			pr_err("invalid xattr record size\n");
548 			res = -EIO;
549 			goto out;
550 		}
551 	} else if (record_type == HFSPLUS_ATTR_FORK_DATA ||
552 			record_type == HFSPLUS_ATTR_EXTENTS) {
553 		pr_err("only inline data xattr are supported\n");
554 		res = -EOPNOTSUPP;
555 		goto out;
556 	} else {
557 		pr_err("invalid xattr record\n");
558 		res = -EIO;
559 		goto out;
560 	}
561 
562 	if (size) {
563 		hfs_bnode_read(fd.bnode, entry, fd.entryoffset,
564 				offsetof(struct hfsplus_attr_inline_data,
565 					raw_bytes) + record_length);
566 	}
567 
568 	if (size >= record_length) {
569 		memcpy(value, entry->inline_data.raw_bytes, record_length);
570 		res = record_length;
571 	} else
572 		res = size ? -ERANGE : record_length;
573 
574 out:
575 	hfs_find_exit(&fd);
576 
577 failed_getxattr_init:
578 	hfsplus_destroy_attr_entry(entry);
579 	return res;
580 }
581 
582 ssize_t hfsplus_getxattr(struct dentry *dentry, const char *name,
583 			 void *value, size_t size,
584 			 const char *prefix, size_t prefixlen)
585 {
586 	int res;
587 	char *xattr_name;
588 
589 	xattr_name = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN + 1,
590 			     GFP_KERNEL);
591 	if (!xattr_name)
592 		return -ENOMEM;
593 
594 	strcpy(xattr_name, prefix);
595 	strcpy(xattr_name + prefixlen, name);
596 
597 	res = __hfsplus_getxattr(d_inode(dentry), xattr_name, value, size);
598 	kfree(xattr_name);
599 	return res;
600 
601 }
602 
603 static inline int can_list(const char *xattr_name)
604 {
605 	if (!xattr_name)
606 		return 0;
607 
608 	return strncmp(xattr_name, XATTR_TRUSTED_PREFIX,
609 			XATTR_TRUSTED_PREFIX_LEN) ||
610 				capable(CAP_SYS_ADMIN);
611 }
612 
613 static ssize_t hfsplus_listxattr_finder_info(struct dentry *dentry,
614 						char *buffer, size_t size)
615 {
616 	ssize_t res = 0;
617 	struct inode *inode = d_inode(dentry);
618 	struct hfs_find_data fd;
619 	u16 entry_type;
620 	u8 folder_finder_info[sizeof(struct DInfo) + sizeof(struct DXInfo)];
621 	u8 file_finder_info[sizeof(struct FInfo) + sizeof(struct FXInfo)];
622 	unsigned long len, found_bit;
623 	int xattr_name_len, symbols_count;
624 
625 	res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &fd);
626 	if (res) {
627 		pr_err("can't init xattr find struct\n");
628 		return res;
629 	}
630 
631 	res = hfsplus_find_cat(inode->i_sb, inode->i_ino, &fd);
632 	if (res)
633 		goto end_listxattr_finder_info;
634 
635 	entry_type = hfs_bnode_read_u16(fd.bnode, fd.entryoffset);
636 	if (entry_type == HFSPLUS_FOLDER) {
637 		len = sizeof(struct DInfo) + sizeof(struct DXInfo);
638 		hfs_bnode_read(fd.bnode, folder_finder_info,
639 				fd.entryoffset +
640 				offsetof(struct hfsplus_cat_folder, user_info),
641 				len);
642 		found_bit = find_first_bit((void *)folder_finder_info, len*8);
643 	} else if (entry_type == HFSPLUS_FILE) {
644 		len = sizeof(struct FInfo) + sizeof(struct FXInfo);
645 		hfs_bnode_read(fd.bnode, file_finder_info,
646 				fd.entryoffset +
647 				offsetof(struct hfsplus_cat_file, user_info),
648 				len);
649 		found_bit = find_first_bit((void *)file_finder_info, len*8);
650 	} else {
651 		res = -EOPNOTSUPP;
652 		goto end_listxattr_finder_info;
653 	}
654 
655 	if (found_bit >= (len*8))
656 		res = 0;
657 	else {
658 		symbols_count = sizeof(HFSPLUS_XATTR_FINDER_INFO_NAME) - 1;
659 		xattr_name_len =
660 			name_len(HFSPLUS_XATTR_FINDER_INFO_NAME, symbols_count);
661 		if (!buffer || !size) {
662 			if (can_list(HFSPLUS_XATTR_FINDER_INFO_NAME))
663 				res = xattr_name_len;
664 		} else if (can_list(HFSPLUS_XATTR_FINDER_INFO_NAME)) {
665 			if (size < xattr_name_len)
666 				res = -ERANGE;
667 			else {
668 				res = copy_name(buffer,
669 						HFSPLUS_XATTR_FINDER_INFO_NAME,
670 						symbols_count);
671 			}
672 		}
673 	}
674 
675 end_listxattr_finder_info:
676 	hfs_find_exit(&fd);
677 
678 	return res;
679 }
680 
681 ssize_t hfsplus_listxattr(struct dentry *dentry, char *buffer, size_t size)
682 {
683 	ssize_t err;
684 	ssize_t res = 0;
685 	struct inode *inode = d_inode(dentry);
686 	struct hfs_find_data fd;
687 	u16 key_len = 0;
688 	struct hfsplus_attr_key attr_key;
689 	char *strbuf;
690 	int xattr_name_len;
691 
692 	if ((!S_ISREG(inode->i_mode) &&
693 			!S_ISDIR(inode->i_mode)) ||
694 				HFSPLUS_IS_RSRC(inode))
695 		return -EOPNOTSUPP;
696 
697 	res = hfsplus_listxattr_finder_info(dentry, buffer, size);
698 	if (res < 0)
699 		return res;
700 	else if (!HFSPLUS_SB(inode->i_sb)->attr_tree)
701 		return (res == 0) ? -EOPNOTSUPP : res;
702 
703 	err = hfs_find_init(HFSPLUS_SB(inode->i_sb)->attr_tree, &fd);
704 	if (err) {
705 		pr_err("can't init xattr find struct\n");
706 		return err;
707 	}
708 
709 	strbuf = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN +
710 			XATTR_MAC_OSX_PREFIX_LEN + 1, GFP_KERNEL);
711 	if (!strbuf) {
712 		res = -ENOMEM;
713 		goto out;
714 	}
715 
716 	err = hfsplus_find_attr(inode->i_sb, inode->i_ino, NULL, &fd);
717 	if (err) {
718 		if (err == -ENOENT) {
719 			if (res == 0)
720 				res = -ENODATA;
721 			goto end_listxattr;
722 		} else {
723 			res = err;
724 			goto end_listxattr;
725 		}
726 	}
727 
728 	for (;;) {
729 		key_len = hfs_bnode_read_u16(fd.bnode, fd.keyoffset);
730 		if (key_len == 0 || key_len > fd.tree->max_key_len) {
731 			pr_err("invalid xattr key length: %d\n", key_len);
732 			res = -EIO;
733 			goto end_listxattr;
734 		}
735 
736 		hfs_bnode_read(fd.bnode, &attr_key,
737 				fd.keyoffset, key_len + sizeof(key_len));
738 
739 		if (be32_to_cpu(attr_key.cnid) != inode->i_ino)
740 			goto end_listxattr;
741 
742 		xattr_name_len = NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN;
743 		if (hfsplus_uni2asc(inode->i_sb,
744 			(const struct hfsplus_unistr *)&fd.key->attr.key_name,
745 					strbuf, &xattr_name_len)) {
746 			pr_err("unicode conversion failed\n");
747 			res = -EIO;
748 			goto end_listxattr;
749 		}
750 
751 		if (!buffer || !size) {
752 			if (can_list(strbuf))
753 				res += name_len(strbuf, xattr_name_len);
754 		} else if (can_list(strbuf)) {
755 			if (size < (res + name_len(strbuf, xattr_name_len))) {
756 				res = -ERANGE;
757 				goto end_listxattr;
758 			} else
759 				res += copy_name(buffer + res,
760 						strbuf, xattr_name_len);
761 		}
762 
763 		if (hfs_brec_goto(&fd, 1))
764 			goto end_listxattr;
765 	}
766 
767 end_listxattr:
768 	kfree(strbuf);
769 out:
770 	hfs_find_exit(&fd);
771 	return res;
772 }
773 
774 static int hfsplus_removexattr(struct inode *inode, const char *name)
775 {
776 	int err = 0;
777 	struct hfs_find_data cat_fd;
778 	u16 flags;
779 	u16 cat_entry_type;
780 	int is_xattr_acl_deleted = 0;
781 	int is_all_xattrs_deleted = 0;
782 
783 	if (!HFSPLUS_SB(inode->i_sb)->attr_tree)
784 		return -EOPNOTSUPP;
785 
786 	if (!strcmp_xattr_finder_info(name))
787 		return -EOPNOTSUPP;
788 
789 	err = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &cat_fd);
790 	if (err) {
791 		pr_err("can't init xattr find struct\n");
792 		return err;
793 	}
794 
795 	err = hfsplus_find_cat(inode->i_sb, inode->i_ino, &cat_fd);
796 	if (err) {
797 		pr_err("catalog searching failed\n");
798 		goto end_removexattr;
799 	}
800 
801 	err = hfsplus_delete_attr(inode, name);
802 	if (err)
803 		goto end_removexattr;
804 
805 	is_xattr_acl_deleted = !strcmp_xattr_acl(name);
806 	is_all_xattrs_deleted = !hfsplus_attr_exists(inode, NULL);
807 
808 	if (!is_xattr_acl_deleted && !is_all_xattrs_deleted)
809 		goto end_removexattr;
810 
811 	cat_entry_type = hfs_bnode_read_u16(cat_fd.bnode, cat_fd.entryoffset);
812 
813 	if (cat_entry_type == HFSPLUS_FOLDER) {
814 		flags = hfs_bnode_read_u16(cat_fd.bnode, cat_fd.entryoffset +
815 				offsetof(struct hfsplus_cat_folder, flags));
816 		if (is_xattr_acl_deleted)
817 			flags &= ~HFSPLUS_ACL_EXISTS;
818 		if (is_all_xattrs_deleted)
819 			flags &= ~HFSPLUS_XATTR_EXISTS;
820 		hfs_bnode_write_u16(cat_fd.bnode, cat_fd.entryoffset +
821 				offsetof(struct hfsplus_cat_folder, flags),
822 				flags);
823 		hfsplus_mark_inode_dirty(inode, HFSPLUS_I_CAT_DIRTY);
824 	} else if (cat_entry_type == HFSPLUS_FILE) {
825 		flags = hfs_bnode_read_u16(cat_fd.bnode, cat_fd.entryoffset +
826 				offsetof(struct hfsplus_cat_file, flags));
827 		if (is_xattr_acl_deleted)
828 			flags &= ~HFSPLUS_ACL_EXISTS;
829 		if (is_all_xattrs_deleted)
830 			flags &= ~HFSPLUS_XATTR_EXISTS;
831 		hfs_bnode_write_u16(cat_fd.bnode, cat_fd.entryoffset +
832 				offsetof(struct hfsplus_cat_file, flags),
833 				flags);
834 		hfsplus_mark_inode_dirty(inode, HFSPLUS_I_CAT_DIRTY);
835 	} else {
836 		pr_err("invalid catalog entry type\n");
837 		err = -EIO;
838 		goto end_removexattr;
839 	}
840 
841 end_removexattr:
842 	hfs_find_exit(&cat_fd);
843 	return err;
844 }
845 
846 static int hfsplus_osx_getxattr(const struct xattr_handler *handler,
847 				struct dentry *dentry, const char *name,
848 				void *buffer, size_t size)
849 {
850 	/*
851 	 * Don't allow retrieving properly prefixed attributes
852 	 * by prepending them with "osx."
853 	 */
854 	if (is_known_namespace(name))
855 		return -EOPNOTSUPP;
856 
857 	/*
858 	 * osx is the namespace we use to indicate an unprefixed
859 	 * attribute on the filesystem (like the ones that OS X
860 	 * creates), so we pass the name through unmodified (after
861 	 * ensuring it doesn't conflict with another namespace).
862 	 */
863 	return __hfsplus_getxattr(d_inode(dentry), name, buffer, size);
864 }
865 
866 static int hfsplus_osx_setxattr(const struct xattr_handler *handler,
867 				struct dentry *dentry, const char *name,
868 				const void *buffer, size_t size, int flags)
869 {
870 	/*
871 	 * Don't allow setting properly prefixed attributes
872 	 * by prepending them with "osx."
873 	 */
874 	if (is_known_namespace(name))
875 		return -EOPNOTSUPP;
876 
877 	/*
878 	 * osx is the namespace we use to indicate an unprefixed
879 	 * attribute on the filesystem (like the ones that OS X
880 	 * creates), so we pass the name through unmodified (after
881 	 * ensuring it doesn't conflict with another namespace).
882 	 */
883 	return __hfsplus_setxattr(d_inode(dentry), name, buffer, size, flags);
884 }
885 
886 const struct xattr_handler hfsplus_xattr_osx_handler = {
887 	.prefix	= XATTR_MAC_OSX_PREFIX,
888 	.get	= hfsplus_osx_getxattr,
889 	.set	= hfsplus_osx_setxattr,
890 };
891