xref: /linux/fs/hfsplus/xattr.c (revision 6f7e6393d1ce636bb7ec77a7fe7b77458fddf701)
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("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("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 	if (i_size_read(attr_file) != 0) {
176 		err = -EIO;
177 		pr_err("detected inconsistent attributes file, running fsck.hfsplus is recommended.\n");
178 		goto end_attr_file_creation;
179 	}
180 
181 	hip = HFSPLUS_I(attr_file);
182 
183 	clump_size = hfsplus_calc_btree_clump_size(sb->s_blocksize,
184 						    node_size,
185 						    sbi->sect_count,
186 						    HFSPLUS_ATTR_CNID);
187 
188 	mutex_lock(&hip->extents_lock);
189 	hip->clump_blocks = clump_size >> sbi->alloc_blksz_shift;
190 	mutex_unlock(&hip->extents_lock);
191 
192 	if (sbi->free_blocks <= (hip->clump_blocks << 1)) {
193 		err = -ENOSPC;
194 		goto end_attr_file_creation;
195 	}
196 
197 	while (hip->alloc_blocks < hip->clump_blocks) {
198 		err = hfsplus_file_extend(attr_file, false);
199 		if (unlikely(err)) {
200 			pr_err("failed to extend attributes file\n");
201 			goto end_attr_file_creation;
202 		}
203 		hip->phys_size = attr_file->i_size =
204 			(loff_t)hip->alloc_blocks << sbi->alloc_blksz_shift;
205 		hip->fs_blocks = hip->alloc_blocks << sbi->fs_shift;
206 		inode_set_bytes(attr_file, attr_file->i_size);
207 	}
208 
209 	buf = kzalloc(node_size, GFP_NOFS);
210 	if (!buf) {
211 		err = -ENOMEM;
212 		goto end_attr_file_creation;
213 	}
214 
215 	hfsplus_init_header_node(attr_file, clump_size, buf, node_size);
216 
217 	mapping = attr_file->i_mapping;
218 
219 	index = 0;
220 	written = 0;
221 	for (; written < node_size; index++, written += PAGE_SIZE) {
222 		void *kaddr;
223 
224 		page = read_mapping_page(mapping, index, NULL);
225 		if (IS_ERR(page)) {
226 			err = PTR_ERR(page);
227 			goto failed_header_node_init;
228 		}
229 
230 		kaddr = kmap_atomic(page);
231 		memcpy(kaddr, buf + written,
232 			min_t(size_t, PAGE_SIZE, node_size - written));
233 		kunmap_atomic(kaddr);
234 
235 		set_page_dirty(page);
236 		put_page(page);
237 	}
238 
239 	hfsplus_mark_inode_dirty(attr_file, HFSPLUS_I_ATTR_DIRTY);
240 
241 	sbi->attr_tree = hfs_btree_open(sb, HFSPLUS_ATTR_CNID);
242 	if (!sbi->attr_tree)
243 		pr_err("failed to load attributes file\n");
244 
245 failed_header_node_init:
246 	kfree(buf);
247 
248 end_attr_file_creation:
249 	iput(attr_file);
250 
251 	if (!err)
252 		atomic_set(&sbi->attr_tree_state, HFSPLUS_VALID_ATTR_TREE);
253 	else if (err == -ENOSPC)
254 		atomic_set(&sbi->attr_tree_state, HFSPLUS_EMPTY_ATTR_TREE);
255 	else
256 		atomic_set(&sbi->attr_tree_state, HFSPLUS_FAILED_ATTR_TREE);
257 
258 	return err;
259 }
260 
261 static inline
262 bool is_xattr_operation_supported(struct inode *inode)
263 {
264 	if (HFSPLUS_IS_RSRC(inode))
265 		return false;
266 
267 	return true;
268 }
269 
270 int __hfsplus_setxattr(struct inode *inode, const char *name,
271 			const void *value, size_t size, int flags)
272 {
273 	int err;
274 	struct hfs_find_data cat_fd;
275 	hfsplus_cat_entry entry;
276 	u16 cat_entry_flags, cat_entry_type;
277 	u16 folder_finderinfo_len = sizeof(DInfo) + sizeof(DXInfo);
278 	u16 file_finderinfo_len = sizeof(FInfo) + sizeof(FXInfo);
279 
280 	hfs_dbg("ino %lu, name %s, value %p, size %zu\n",
281 		inode->i_ino, name ? name : NULL,
282 		value, size);
283 
284 	if (!is_xattr_operation_supported(inode))
285 		return -EOPNOTSUPP;
286 
287 	if (value == NULL)
288 		return hfsplus_removexattr(inode, name);
289 
290 	err = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &cat_fd);
291 	if (err) {
292 		pr_err("can't init xattr find struct\n");
293 		return err;
294 	}
295 
296 	err = hfsplus_find_cat(inode->i_sb, inode->i_ino, &cat_fd);
297 	if (err) {
298 		pr_err("catalog searching failed\n");
299 		goto end_setxattr;
300 	}
301 
302 	if (!strcmp_xattr_finder_info(name)) {
303 		if (flags & XATTR_CREATE) {
304 			pr_err("xattr exists yet\n");
305 			err = -EOPNOTSUPP;
306 			goto end_setxattr;
307 		}
308 		hfs_bnode_read(cat_fd.bnode, &entry, cat_fd.entryoffset,
309 					sizeof(hfsplus_cat_entry));
310 		if (be16_to_cpu(entry.type) == HFSPLUS_FOLDER) {
311 			if (size == folder_finderinfo_len) {
312 				memcpy(&entry.folder.info, value,
313 						folder_finderinfo_len);
314 				hfs_bnode_write(cat_fd.bnode, &entry,
315 					cat_fd.entryoffset,
316 					sizeof(struct hfsplus_cat_folder));
317 				hfsplus_mark_inode_dirty(inode,
318 						HFSPLUS_I_CAT_DIRTY);
319 			} else {
320 				err = -ERANGE;
321 				goto end_setxattr;
322 			}
323 		} else if (be16_to_cpu(entry.type) == HFSPLUS_FILE) {
324 			if (size == file_finderinfo_len) {
325 				memcpy(&entry.file.info, value,
326 						file_finderinfo_len);
327 				hfs_bnode_write(cat_fd.bnode, &entry,
328 					cat_fd.entryoffset,
329 					sizeof(struct hfsplus_cat_file));
330 				hfsplus_mark_inode_dirty(inode,
331 						HFSPLUS_I_CAT_DIRTY);
332 			} else {
333 				err = -ERANGE;
334 				goto end_setxattr;
335 			}
336 		} else {
337 			err = -EOPNOTSUPP;
338 			goto end_setxattr;
339 		}
340 		goto end_setxattr;
341 	}
342 
343 	if (!HFSPLUS_SB(inode->i_sb)->attr_tree) {
344 		err = hfsplus_create_attributes_file(inode->i_sb);
345 		if (unlikely(err))
346 			goto end_setxattr;
347 	}
348 
349 	if (hfsplus_attr_exists(inode, name)) {
350 		if (flags & XATTR_CREATE) {
351 			pr_err("xattr exists yet\n");
352 			err = -EOPNOTSUPP;
353 			goto end_setxattr;
354 		}
355 		err = hfsplus_replace_attr(inode, name, value, size);
356 		if (err) {
357 			hfs_dbg("unable to replace xattr: err %d\n", err);
358 			goto end_setxattr;
359 		}
360 	} else {
361 		if (flags & XATTR_REPLACE) {
362 			pr_err("cannot replace xattr\n");
363 			err = -EOPNOTSUPP;
364 			goto end_setxattr;
365 		}
366 		err = hfsplus_create_attr(inode, name, value, size);
367 		if (err) {
368 			hfs_dbg("unable to store value: err %d\n", err);
369 			goto end_setxattr;
370 		}
371 	}
372 
373 	cat_entry_type = hfs_bnode_read_u16(cat_fd.bnode, cat_fd.entryoffset);
374 	if (cat_entry_type == HFSPLUS_FOLDER) {
375 		cat_entry_flags = hfs_bnode_read_u16(cat_fd.bnode,
376 				    cat_fd.entryoffset +
377 				    offsetof(struct hfsplus_cat_folder, flags));
378 		cat_entry_flags |= HFSPLUS_XATTR_EXISTS;
379 		if (!strcmp_xattr_acl(name))
380 			cat_entry_flags |= HFSPLUS_ACL_EXISTS;
381 		hfs_bnode_write_u16(cat_fd.bnode, cat_fd.entryoffset +
382 				offsetof(struct hfsplus_cat_folder, flags),
383 				cat_entry_flags);
384 		hfsplus_mark_inode_dirty(inode, HFSPLUS_I_CAT_DIRTY);
385 	} else if (cat_entry_type == HFSPLUS_FILE) {
386 		cat_entry_flags = hfs_bnode_read_u16(cat_fd.bnode,
387 				    cat_fd.entryoffset +
388 				    offsetof(struct hfsplus_cat_file, flags));
389 		cat_entry_flags |= HFSPLUS_XATTR_EXISTS;
390 		if (!strcmp_xattr_acl(name))
391 			cat_entry_flags |= HFSPLUS_ACL_EXISTS;
392 		hfs_bnode_write_u16(cat_fd.bnode, cat_fd.entryoffset +
393 				    offsetof(struct hfsplus_cat_file, flags),
394 				    cat_entry_flags);
395 		hfsplus_mark_inode_dirty(inode, HFSPLUS_I_CAT_DIRTY);
396 	} else {
397 		pr_err("invalid catalog entry type\n");
398 		err = -EIO;
399 		goto end_setxattr;
400 	}
401 
402 end_setxattr:
403 	hfs_find_exit(&cat_fd);
404 	hfs_dbg("finished: res %d\n", err);
405 	return err;
406 }
407 
408 static size_t name_len(const char *xattr_name, size_t xattr_name_len)
409 {
410 	size_t len = xattr_name_len + 1;
411 
412 	if (!is_known_namespace(xattr_name))
413 		len += XATTR_MAC_OSX_PREFIX_LEN;
414 
415 	return len;
416 }
417 
418 static ssize_t copy_name(char *buffer, const char *xattr_name, size_t name_len)
419 {
420 	ssize_t len;
421 
422 	memset(buffer, 0, name_len);
423 
424 	if (!is_known_namespace(xattr_name)) {
425 		len = scnprintf(buffer, name_len + XATTR_MAC_OSX_PREFIX_LEN,
426 				 "%s%s", XATTR_MAC_OSX_PREFIX, xattr_name);
427 	} else {
428 		len = strscpy(buffer, xattr_name, name_len + 1);
429 		if (len < 0) {
430 			pr_err("fail to copy name: err %zd\n", len);
431 			len = 0;
432 		}
433 	}
434 
435 	/* include NUL-byte in length for non-empty name */
436 	if (len >= 0)
437 		len++;
438 	return len;
439 }
440 
441 int hfsplus_setxattr(struct inode *inode, const char *name,
442 		     const void *value, size_t size, int flags,
443 		     const char *prefix, size_t prefixlen)
444 {
445 	char *xattr_name;
446 	size_t xattr_name_len =
447 		NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN + 1;
448 	int res;
449 
450 	hfs_dbg("ino %lu, name %s, prefix %s, prefixlen %zu, "
451 		"value %p, size %zu\n",
452 		inode->i_ino, name ? name : NULL,
453 		prefix ? prefix : NULL, prefixlen,
454 		value, size);
455 
456 	xattr_name = kmalloc(xattr_name_len, GFP_KERNEL);
457 	if (!xattr_name)
458 		return -ENOMEM;
459 	strcpy(xattr_name, prefix);
460 	strcpy(xattr_name + prefixlen, name);
461 	res = __hfsplus_setxattr(inode, xattr_name, value, size, flags);
462 	kfree(xattr_name);
463 
464 	hfs_dbg("finished: res %d\n", res);
465 
466 	return res;
467 }
468 
469 static ssize_t hfsplus_getxattr_finder_info(struct inode *inode,
470 						void *value, size_t size)
471 {
472 	ssize_t res = 0;
473 	struct hfs_find_data fd;
474 	u16 entry_type;
475 	u16 folder_rec_len = sizeof(DInfo) + sizeof(DXInfo);
476 	u16 file_rec_len = sizeof(FInfo) + sizeof(FXInfo);
477 	u16 record_len = max(folder_rec_len, file_rec_len);
478 	u8 folder_finder_info[sizeof(DInfo) + sizeof(DXInfo)];
479 	u8 file_finder_info[sizeof(FInfo) + sizeof(FXInfo)];
480 
481 	if (size >= record_len) {
482 		res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &fd);
483 		if (res) {
484 			pr_err("can't init xattr find struct\n");
485 			return res;
486 		}
487 		res = hfsplus_find_cat(inode->i_sb, inode->i_ino, &fd);
488 		if (res)
489 			goto end_getxattr_finder_info;
490 		entry_type = hfs_bnode_read_u16(fd.bnode, fd.entryoffset);
491 
492 		if (entry_type == HFSPLUS_FOLDER) {
493 			hfs_bnode_read(fd.bnode, folder_finder_info,
494 				fd.entryoffset +
495 				offsetof(struct hfsplus_cat_folder, user_info),
496 				folder_rec_len);
497 			memcpy(value, folder_finder_info, folder_rec_len);
498 			res = folder_rec_len;
499 		} else if (entry_type == HFSPLUS_FILE) {
500 			hfs_bnode_read(fd.bnode, file_finder_info,
501 				fd.entryoffset +
502 				offsetof(struct hfsplus_cat_file, user_info),
503 				file_rec_len);
504 			memcpy(value, file_finder_info, file_rec_len);
505 			res = file_rec_len;
506 		} else {
507 			res = -EOPNOTSUPP;
508 			goto end_getxattr_finder_info;
509 		}
510 	} else
511 		res = size ? -ERANGE : record_len;
512 
513 end_getxattr_finder_info:
514 	if (size >= record_len)
515 		hfs_find_exit(&fd);
516 	return res;
517 }
518 
519 ssize_t __hfsplus_getxattr(struct inode *inode, const char *name,
520 			 void *value, size_t size)
521 {
522 	struct hfs_find_data fd;
523 	hfsplus_attr_entry *entry;
524 	__be32 xattr_record_type;
525 	u32 record_type;
526 	u16 record_length = 0;
527 	ssize_t res;
528 
529 	if (!is_xattr_operation_supported(inode))
530 		return -EOPNOTSUPP;
531 
532 	if (!strcmp_xattr_finder_info(name))
533 		return hfsplus_getxattr_finder_info(inode, value, size);
534 
535 	if (!HFSPLUS_SB(inode->i_sb)->attr_tree)
536 		return -EOPNOTSUPP;
537 
538 	entry = hfsplus_alloc_attr_entry();
539 	if (!entry) {
540 		pr_err("can't allocate xattr entry\n");
541 		return -ENOMEM;
542 	}
543 
544 	res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->attr_tree, &fd);
545 	if (res) {
546 		pr_err("can't init xattr find struct\n");
547 		goto failed_getxattr_init;
548 	}
549 
550 	res = hfsplus_find_attr(inode->i_sb, inode->i_ino, name, &fd);
551 	if (res) {
552 		if (res == -ENOENT)
553 			res = -ENODATA;
554 		else
555 			pr_err("xattr searching failed\n");
556 		goto out;
557 	}
558 
559 	hfs_bnode_read(fd.bnode, &xattr_record_type,
560 			fd.entryoffset, sizeof(xattr_record_type));
561 	record_type = be32_to_cpu(xattr_record_type);
562 	if (record_type == HFSPLUS_ATTR_INLINE_DATA) {
563 		record_length = hfs_bnode_read_u16(fd.bnode,
564 				fd.entryoffset +
565 				offsetof(struct hfsplus_attr_inline_data,
566 				length));
567 		if (record_length > HFSPLUS_MAX_INLINE_DATA_SIZE) {
568 			pr_err("invalid xattr record size\n");
569 			res = -EIO;
570 			goto out;
571 		}
572 	} else if (record_type == HFSPLUS_ATTR_FORK_DATA ||
573 			record_type == HFSPLUS_ATTR_EXTENTS) {
574 		pr_err("only inline data xattr are supported\n");
575 		res = -EOPNOTSUPP;
576 		goto out;
577 	} else {
578 		pr_err("invalid xattr record\n");
579 		res = -EIO;
580 		goto out;
581 	}
582 
583 	if (size) {
584 		hfs_bnode_read(fd.bnode, entry, fd.entryoffset,
585 				offsetof(struct hfsplus_attr_inline_data,
586 					raw_bytes) + record_length);
587 	}
588 
589 	if (size >= record_length) {
590 		memcpy(value, entry->inline_data.raw_bytes, record_length);
591 		res = record_length;
592 	} else
593 		res = size ? -ERANGE : record_length;
594 
595 out:
596 	hfs_find_exit(&fd);
597 
598 failed_getxattr_init:
599 	hfsplus_destroy_attr_entry(entry);
600 	return res;
601 }
602 
603 ssize_t hfsplus_getxattr(struct inode *inode, const char *name,
604 			 void *value, size_t size,
605 			 const char *prefix, size_t prefixlen)
606 {
607 	int res;
608 	char *xattr_name;
609 
610 	hfs_dbg("ino %lu, name %s, prefix %s\n",
611 		inode->i_ino, name ? name : NULL,
612 		prefix ? prefix : NULL);
613 
614 	xattr_name = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN + 1,
615 			     GFP_KERNEL);
616 	if (!xattr_name)
617 		return -ENOMEM;
618 
619 	strcpy(xattr_name, prefix);
620 	strcpy(xattr_name + prefixlen, name);
621 
622 	res = __hfsplus_getxattr(inode, xattr_name, value, size);
623 	kfree(xattr_name);
624 
625 	hfs_dbg("finished: res %d\n", res);
626 
627 	return res;
628 
629 }
630 
631 static inline int can_list(const char *xattr_name)
632 {
633 	if (!xattr_name)
634 		return 0;
635 
636 	return strncmp(xattr_name, XATTR_TRUSTED_PREFIX,
637 			XATTR_TRUSTED_PREFIX_LEN) ||
638 				capable(CAP_SYS_ADMIN);
639 }
640 
641 static ssize_t hfsplus_listxattr_finder_info(struct dentry *dentry,
642 						char *buffer, size_t size)
643 {
644 	ssize_t res;
645 	struct inode *inode = d_inode(dentry);
646 	struct hfs_find_data fd;
647 	u16 entry_type;
648 	u8 folder_finder_info[sizeof(DInfo) + sizeof(DXInfo)];
649 	u8 file_finder_info[sizeof(FInfo) + sizeof(FXInfo)];
650 	unsigned long len, found_bit;
651 	int xattr_name_len, symbols_count;
652 
653 	res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &fd);
654 	if (res) {
655 		pr_err("can't init xattr find struct\n");
656 		return res;
657 	}
658 
659 	res = hfsplus_find_cat(inode->i_sb, inode->i_ino, &fd);
660 	if (res)
661 		goto end_listxattr_finder_info;
662 
663 	entry_type = hfs_bnode_read_u16(fd.bnode, fd.entryoffset);
664 	if (entry_type == HFSPLUS_FOLDER) {
665 		len = sizeof(DInfo) + sizeof(DXInfo);
666 		hfs_bnode_read(fd.bnode, folder_finder_info,
667 				fd.entryoffset +
668 				offsetof(struct hfsplus_cat_folder, user_info),
669 				len);
670 		found_bit = find_first_bit((void *)folder_finder_info, len*8);
671 	} else if (entry_type == HFSPLUS_FILE) {
672 		len = sizeof(FInfo) + sizeof(FXInfo);
673 		hfs_bnode_read(fd.bnode, file_finder_info,
674 				fd.entryoffset +
675 				offsetof(struct hfsplus_cat_file, user_info),
676 				len);
677 		found_bit = find_first_bit((void *)file_finder_info, len*8);
678 	} else {
679 		res = -EOPNOTSUPP;
680 		goto end_listxattr_finder_info;
681 	}
682 
683 	if (found_bit >= (len*8))
684 		res = 0;
685 	else {
686 		symbols_count = sizeof(HFSPLUS_XATTR_FINDER_INFO_NAME) - 1;
687 		xattr_name_len =
688 			name_len(HFSPLUS_XATTR_FINDER_INFO_NAME, symbols_count);
689 		if (!buffer || !size) {
690 			if (can_list(HFSPLUS_XATTR_FINDER_INFO_NAME))
691 				res = xattr_name_len;
692 		} else if (can_list(HFSPLUS_XATTR_FINDER_INFO_NAME)) {
693 			if (size < xattr_name_len)
694 				res = -ERANGE;
695 			else {
696 				res = copy_name(buffer,
697 						HFSPLUS_XATTR_FINDER_INFO_NAME,
698 						symbols_count);
699 			}
700 		}
701 	}
702 
703 end_listxattr_finder_info:
704 	hfs_find_exit(&fd);
705 
706 	return res;
707 }
708 
709 ssize_t hfsplus_listxattr(struct dentry *dentry, char *buffer, size_t size)
710 {
711 	ssize_t err;
712 	ssize_t res;
713 	struct inode *inode = d_inode(dentry);
714 	struct hfs_find_data fd;
715 	struct hfsplus_attr_key attr_key;
716 	char *strbuf;
717 	size_t strbuf_size;
718 	int xattr_name_len;
719 
720 	hfs_dbg("ino %lu\n", inode->i_ino);
721 
722 	if (!is_xattr_operation_supported(inode))
723 		return -EOPNOTSUPP;
724 
725 	res = hfsplus_listxattr_finder_info(dentry, buffer, size);
726 	if (res < 0)
727 		return res;
728 	else if (!HFSPLUS_SB(inode->i_sb)->attr_tree)
729 		return (res == 0) ? -EOPNOTSUPP : res;
730 
731 	err = hfs_find_init(HFSPLUS_SB(inode->i_sb)->attr_tree, &fd);
732 	if (err) {
733 		pr_err("can't init xattr find struct\n");
734 		return err;
735 	}
736 
737 	strbuf_size = NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN +
738 			XATTR_MAC_OSX_PREFIX_LEN + 1;
739 	strbuf = kzalloc(strbuf_size, GFP_KERNEL);
740 	if (!strbuf) {
741 		res = -ENOMEM;
742 		goto out;
743 	}
744 
745 	err = hfsplus_find_attr(inode->i_sb, inode->i_ino, NULL, &fd);
746 	if (err) {
747 		if (err == -ENOENT) {
748 			res = 0;
749 			goto end_listxattr;
750 		} else {
751 			res = err;
752 			goto end_listxattr;
753 		}
754 	}
755 
756 	for (;;) {
757 		u16 key_len = hfs_bnode_read_u16(fd.bnode, fd.keyoffset);
758 
759 		if (key_len == 0 || key_len > fd.tree->max_key_len) {
760 			pr_err("invalid xattr key length: %d\n", key_len);
761 			res = -EIO;
762 			goto end_listxattr;
763 		}
764 
765 		hfs_bnode_read(fd.bnode, &attr_key,
766 				fd.keyoffset, key_len + sizeof(key_len));
767 
768 		if (be32_to_cpu(attr_key.cnid) != inode->i_ino)
769 			goto end_listxattr;
770 
771 		xattr_name_len = NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN;
772 		if (hfsplus_uni2asc_xattr_str(inode->i_sb,
773 					      &fd.key->attr.key_name, strbuf,
774 					      &xattr_name_len)) {
775 			pr_err("unicode conversion failed\n");
776 			res = -EIO;
777 			goto end_listxattr;
778 		}
779 
780 		if (!buffer || !size) {
781 			if (can_list(strbuf))
782 				res += name_len(strbuf, xattr_name_len);
783 		} else if (can_list(strbuf)) {
784 			if (size < (res + name_len(strbuf, xattr_name_len))) {
785 				pr_err("size %zu, res %zd, name_len %zu\n",
786 					size, res,
787 					name_len(strbuf, xattr_name_len));
788 				res = -ERANGE;
789 				goto end_listxattr;
790 			} else
791 				res += copy_name(buffer + res,
792 						strbuf, xattr_name_len);
793 		}
794 
795 		memset(fd.key->attr.key_name.unicode, 0,
796 			sizeof(fd.key->attr.key_name.unicode));
797 		memset(strbuf, 0, strbuf_size);
798 
799 		if (hfs_brec_goto(&fd, 1))
800 			goto end_listxattr;
801 	}
802 
803 end_listxattr:
804 	kfree(strbuf);
805 out:
806 	hfs_find_exit(&fd);
807 
808 	hfs_dbg("finished: res %zd\n", res);
809 
810 	return res;
811 }
812 
813 static int hfsplus_removexattr(struct inode *inode, const char *name)
814 {
815 	int err;
816 	struct hfs_find_data cat_fd;
817 	u16 flags;
818 	u16 cat_entry_type;
819 	int is_xattr_acl_deleted;
820 	int is_all_xattrs_deleted;
821 
822 	hfs_dbg("ino %lu, name %s\n",
823 		inode->i_ino, name ? name : NULL);
824 
825 	if (!HFSPLUS_SB(inode->i_sb)->attr_tree)
826 		return -EOPNOTSUPP;
827 
828 	if (!strcmp_xattr_finder_info(name))
829 		return -EOPNOTSUPP;
830 
831 	err = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &cat_fd);
832 	if (err) {
833 		pr_err("can't init xattr find struct\n");
834 		return err;
835 	}
836 
837 	err = hfsplus_find_cat(inode->i_sb, inode->i_ino, &cat_fd);
838 	if (err) {
839 		pr_err("catalog searching failed\n");
840 		goto end_removexattr;
841 	}
842 
843 	err = hfsplus_delete_attr(inode, name);
844 	if (err)
845 		goto end_removexattr;
846 
847 	is_xattr_acl_deleted = !strcmp_xattr_acl(name);
848 	is_all_xattrs_deleted = !hfsplus_attr_exists(inode, NULL);
849 
850 	if (!is_xattr_acl_deleted && !is_all_xattrs_deleted)
851 		goto end_removexattr;
852 
853 	cat_entry_type = hfs_bnode_read_u16(cat_fd.bnode, cat_fd.entryoffset);
854 
855 	if (cat_entry_type == HFSPLUS_FOLDER) {
856 		flags = hfs_bnode_read_u16(cat_fd.bnode, cat_fd.entryoffset +
857 				offsetof(struct hfsplus_cat_folder, flags));
858 		if (is_xattr_acl_deleted)
859 			flags &= ~HFSPLUS_ACL_EXISTS;
860 		if (is_all_xattrs_deleted)
861 			flags &= ~HFSPLUS_XATTR_EXISTS;
862 		hfs_bnode_write_u16(cat_fd.bnode, cat_fd.entryoffset +
863 				offsetof(struct hfsplus_cat_folder, flags),
864 				flags);
865 		hfsplus_mark_inode_dirty(inode, HFSPLUS_I_CAT_DIRTY);
866 	} else if (cat_entry_type == HFSPLUS_FILE) {
867 		flags = hfs_bnode_read_u16(cat_fd.bnode, cat_fd.entryoffset +
868 				offsetof(struct hfsplus_cat_file, flags));
869 		if (is_xattr_acl_deleted)
870 			flags &= ~HFSPLUS_ACL_EXISTS;
871 		if (is_all_xattrs_deleted)
872 			flags &= ~HFSPLUS_XATTR_EXISTS;
873 		hfs_bnode_write_u16(cat_fd.bnode, cat_fd.entryoffset +
874 				offsetof(struct hfsplus_cat_file, flags),
875 				flags);
876 		hfsplus_mark_inode_dirty(inode, HFSPLUS_I_CAT_DIRTY);
877 	} else {
878 		pr_err("invalid catalog entry type\n");
879 		err = -EIO;
880 		goto end_removexattr;
881 	}
882 
883 end_removexattr:
884 	hfs_find_exit(&cat_fd);
885 
886 	hfs_dbg("finished: err %d\n", err);
887 
888 	return err;
889 }
890 
891 static int hfsplus_osx_getxattr(const struct xattr_handler *handler,
892 				struct dentry *unused, struct inode *inode,
893 				const char *name, void *buffer, size_t size)
894 {
895 	/*
896 	 * Don't allow retrieving properly prefixed attributes
897 	 * by prepending them with "osx."
898 	 */
899 	if (is_known_namespace(name))
900 		return -EOPNOTSUPP;
901 
902 	/*
903 	 * osx is the namespace we use to indicate an unprefixed
904 	 * attribute on the filesystem (like the ones that OS X
905 	 * creates), so we pass the name through unmodified (after
906 	 * ensuring it doesn't conflict with another namespace).
907 	 */
908 	return __hfsplus_getxattr(inode, name, buffer, size);
909 }
910 
911 static int hfsplus_osx_setxattr(const struct xattr_handler *handler,
912 				struct mnt_idmap *idmap,
913 				struct dentry *unused, struct inode *inode,
914 				const char *name, const void *buffer,
915 				size_t size, int flags)
916 {
917 	/*
918 	 * Don't allow setting properly prefixed attributes
919 	 * by prepending them with "osx."
920 	 */
921 	if (is_known_namespace(name))
922 		return -EOPNOTSUPP;
923 
924 	/*
925 	 * osx is the namespace we use to indicate an unprefixed
926 	 * attribute on the filesystem (like the ones that OS X
927 	 * creates), so we pass the name through unmodified (after
928 	 * ensuring it doesn't conflict with another namespace).
929 	 */
930 	return __hfsplus_setxattr(inode, name, buffer, size, flags);
931 }
932 
933 const struct xattr_handler hfsplus_xattr_osx_handler = {
934 	.prefix	= XATTR_MAC_OSX_PREFIX,
935 	.get	= hfsplus_osx_getxattr,
936 	.set	= hfsplus_osx_setxattr,
937 };
938