xref: /openbmc/linux/fs/hfsplus/xattr.c (revision d9fd5a71)
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 		pr_err("failed to allocate memory for header node\n");
208 		err = -ENOMEM;
209 		goto end_attr_file_creation;
210 	}
211 
212 	hfsplus_init_header_node(attr_file, clump_size, buf, node_size);
213 
214 	mapping = attr_file->i_mapping;
215 
216 	index = 0;
217 	written = 0;
218 	for (; written < node_size; index++, written += PAGE_SIZE) {
219 		void *kaddr;
220 
221 		page = read_mapping_page(mapping, index, NULL);
222 		if (IS_ERR(page)) {
223 			err = PTR_ERR(page);
224 			goto failed_header_node_init;
225 		}
226 
227 		kaddr = kmap_atomic(page);
228 		memcpy(kaddr, buf + written,
229 			min_t(size_t, PAGE_SIZE, node_size - written));
230 		kunmap_atomic(kaddr);
231 
232 		set_page_dirty(page);
233 		put_page(page);
234 	}
235 
236 	hfsplus_mark_inode_dirty(attr_file, HFSPLUS_I_ATTR_DIRTY);
237 
238 	sbi->attr_tree = hfs_btree_open(sb, HFSPLUS_ATTR_CNID);
239 	if (!sbi->attr_tree)
240 		pr_err("failed to load attributes file\n");
241 
242 failed_header_node_init:
243 	kfree(buf);
244 
245 end_attr_file_creation:
246 	iput(attr_file);
247 
248 	if (!err)
249 		atomic_set(&sbi->attr_tree_state, HFSPLUS_VALID_ATTR_TREE);
250 	else if (err == -ENOSPC)
251 		atomic_set(&sbi->attr_tree_state, HFSPLUS_EMPTY_ATTR_TREE);
252 	else
253 		atomic_set(&sbi->attr_tree_state, HFSPLUS_FAILED_ATTR_TREE);
254 
255 	return err;
256 }
257 
258 int __hfsplus_setxattr(struct inode *inode, const char *name,
259 			const void *value, size_t size, int flags)
260 {
261 	int err = 0;
262 	struct hfs_find_data cat_fd;
263 	hfsplus_cat_entry entry;
264 	u16 cat_entry_flags, cat_entry_type;
265 	u16 folder_finderinfo_len = sizeof(struct DInfo) +
266 					sizeof(struct DXInfo);
267 	u16 file_finderinfo_len = sizeof(struct FInfo) +
268 					sizeof(struct FXInfo);
269 
270 	if ((!S_ISREG(inode->i_mode) &&
271 			!S_ISDIR(inode->i_mode)) ||
272 				HFSPLUS_IS_RSRC(inode))
273 		return -EOPNOTSUPP;
274 
275 	if (value == NULL)
276 		return hfsplus_removexattr(inode, name);
277 
278 	err = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &cat_fd);
279 	if (err) {
280 		pr_err("can't init xattr find struct\n");
281 		return err;
282 	}
283 
284 	err = hfsplus_find_cat(inode->i_sb, inode->i_ino, &cat_fd);
285 	if (err) {
286 		pr_err("catalog searching failed\n");
287 		goto end_setxattr;
288 	}
289 
290 	if (!strcmp_xattr_finder_info(name)) {
291 		if (flags & XATTR_CREATE) {
292 			pr_err("xattr exists yet\n");
293 			err = -EOPNOTSUPP;
294 			goto end_setxattr;
295 		}
296 		hfs_bnode_read(cat_fd.bnode, &entry, cat_fd.entryoffset,
297 					sizeof(hfsplus_cat_entry));
298 		if (be16_to_cpu(entry.type) == HFSPLUS_FOLDER) {
299 			if (size == folder_finderinfo_len) {
300 				memcpy(&entry.folder.user_info, value,
301 						folder_finderinfo_len);
302 				hfs_bnode_write(cat_fd.bnode, &entry,
303 					cat_fd.entryoffset,
304 					sizeof(struct hfsplus_cat_folder));
305 				hfsplus_mark_inode_dirty(inode,
306 						HFSPLUS_I_CAT_DIRTY);
307 			} else {
308 				err = -ERANGE;
309 				goto end_setxattr;
310 			}
311 		} else if (be16_to_cpu(entry.type) == HFSPLUS_FILE) {
312 			if (size == file_finderinfo_len) {
313 				memcpy(&entry.file.user_info, value,
314 						file_finderinfo_len);
315 				hfs_bnode_write(cat_fd.bnode, &entry,
316 					cat_fd.entryoffset,
317 					sizeof(struct hfsplus_cat_file));
318 				hfsplus_mark_inode_dirty(inode,
319 						HFSPLUS_I_CAT_DIRTY);
320 			} else {
321 				err = -ERANGE;
322 				goto end_setxattr;
323 			}
324 		} else {
325 			err = -EOPNOTSUPP;
326 			goto end_setxattr;
327 		}
328 		goto end_setxattr;
329 	}
330 
331 	if (!HFSPLUS_SB(inode->i_sb)->attr_tree) {
332 		err = hfsplus_create_attributes_file(inode->i_sb);
333 		if (unlikely(err))
334 			goto end_setxattr;
335 	}
336 
337 	if (hfsplus_attr_exists(inode, name)) {
338 		if (flags & XATTR_CREATE) {
339 			pr_err("xattr exists yet\n");
340 			err = -EOPNOTSUPP;
341 			goto end_setxattr;
342 		}
343 		err = hfsplus_delete_attr(inode, name);
344 		if (err)
345 			goto end_setxattr;
346 		err = hfsplus_create_attr(inode, name, value, size);
347 		if (err)
348 			goto end_setxattr;
349 	} else {
350 		if (flags & XATTR_REPLACE) {
351 			pr_err("cannot replace xattr\n");
352 			err = -EOPNOTSUPP;
353 			goto end_setxattr;
354 		}
355 		err = hfsplus_create_attr(inode, name, value, size);
356 		if (err)
357 			goto end_setxattr;
358 	}
359 
360 	cat_entry_type = hfs_bnode_read_u16(cat_fd.bnode, cat_fd.entryoffset);
361 	if (cat_entry_type == HFSPLUS_FOLDER) {
362 		cat_entry_flags = hfs_bnode_read_u16(cat_fd.bnode,
363 				    cat_fd.entryoffset +
364 				    offsetof(struct hfsplus_cat_folder, flags));
365 		cat_entry_flags |= HFSPLUS_XATTR_EXISTS;
366 		if (!strcmp_xattr_acl(name))
367 			cat_entry_flags |= HFSPLUS_ACL_EXISTS;
368 		hfs_bnode_write_u16(cat_fd.bnode, cat_fd.entryoffset +
369 				offsetof(struct hfsplus_cat_folder, flags),
370 				cat_entry_flags);
371 		hfsplus_mark_inode_dirty(inode, HFSPLUS_I_CAT_DIRTY);
372 	} else if (cat_entry_type == HFSPLUS_FILE) {
373 		cat_entry_flags = hfs_bnode_read_u16(cat_fd.bnode,
374 				    cat_fd.entryoffset +
375 				    offsetof(struct hfsplus_cat_file, flags));
376 		cat_entry_flags |= HFSPLUS_XATTR_EXISTS;
377 		if (!strcmp_xattr_acl(name))
378 			cat_entry_flags |= HFSPLUS_ACL_EXISTS;
379 		hfs_bnode_write_u16(cat_fd.bnode, cat_fd.entryoffset +
380 				    offsetof(struct hfsplus_cat_file, flags),
381 				    cat_entry_flags);
382 		hfsplus_mark_inode_dirty(inode, HFSPLUS_I_CAT_DIRTY);
383 	} else {
384 		pr_err("invalid catalog entry type\n");
385 		err = -EIO;
386 		goto end_setxattr;
387 	}
388 
389 end_setxattr:
390 	hfs_find_exit(&cat_fd);
391 	return err;
392 }
393 
394 static int name_len(const char *xattr_name, int xattr_name_len)
395 {
396 	int len = xattr_name_len + 1;
397 
398 	if (!is_known_namespace(xattr_name))
399 		len += XATTR_MAC_OSX_PREFIX_LEN;
400 
401 	return len;
402 }
403 
404 static int copy_name(char *buffer, const char *xattr_name, int name_len)
405 {
406 	int len = name_len;
407 	int offset = 0;
408 
409 	if (!is_known_namespace(xattr_name)) {
410 		memcpy(buffer, XATTR_MAC_OSX_PREFIX, XATTR_MAC_OSX_PREFIX_LEN);
411 		offset += XATTR_MAC_OSX_PREFIX_LEN;
412 		len += XATTR_MAC_OSX_PREFIX_LEN;
413 	}
414 
415 	strncpy(buffer + offset, xattr_name, name_len);
416 	memset(buffer + offset + name_len, 0, 1);
417 	len += 1;
418 
419 	return len;
420 }
421 
422 int hfsplus_setxattr(struct inode *inode, const char *name,
423 		     const void *value, size_t size, int flags,
424 		     const char *prefix, size_t prefixlen)
425 {
426 	char *xattr_name;
427 	int res;
428 
429 	xattr_name = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN + 1,
430 		GFP_KERNEL);
431 	if (!xattr_name)
432 		return -ENOMEM;
433 	strcpy(xattr_name, prefix);
434 	strcpy(xattr_name + prefixlen, name);
435 	res = __hfsplus_setxattr(inode, xattr_name, value, size, flags);
436 	kfree(xattr_name);
437 	return res;
438 }
439 
440 static ssize_t hfsplus_getxattr_finder_info(struct inode *inode,
441 						void *value, size_t size)
442 {
443 	ssize_t res = 0;
444 	struct hfs_find_data fd;
445 	u16 entry_type;
446 	u16 folder_rec_len = sizeof(struct DInfo) + sizeof(struct DXInfo);
447 	u16 file_rec_len = sizeof(struct FInfo) + sizeof(struct FXInfo);
448 	u16 record_len = max(folder_rec_len, file_rec_len);
449 	u8 folder_finder_info[sizeof(struct DInfo) + sizeof(struct DXInfo)];
450 	u8 file_finder_info[sizeof(struct FInfo) + sizeof(struct FXInfo)];
451 
452 	if (size >= record_len) {
453 		res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &fd);
454 		if (res) {
455 			pr_err("can't init xattr find struct\n");
456 			return res;
457 		}
458 		res = hfsplus_find_cat(inode->i_sb, inode->i_ino, &fd);
459 		if (res)
460 			goto end_getxattr_finder_info;
461 		entry_type = hfs_bnode_read_u16(fd.bnode, fd.entryoffset);
462 
463 		if (entry_type == HFSPLUS_FOLDER) {
464 			hfs_bnode_read(fd.bnode, folder_finder_info,
465 				fd.entryoffset +
466 				offsetof(struct hfsplus_cat_folder, user_info),
467 				folder_rec_len);
468 			memcpy(value, folder_finder_info, folder_rec_len);
469 			res = folder_rec_len;
470 		} else if (entry_type == HFSPLUS_FILE) {
471 			hfs_bnode_read(fd.bnode, file_finder_info,
472 				fd.entryoffset +
473 				offsetof(struct hfsplus_cat_file, user_info),
474 				file_rec_len);
475 			memcpy(value, file_finder_info, file_rec_len);
476 			res = file_rec_len;
477 		} else {
478 			res = -EOPNOTSUPP;
479 			goto end_getxattr_finder_info;
480 		}
481 	} else
482 		res = size ? -ERANGE : record_len;
483 
484 end_getxattr_finder_info:
485 	if (size >= record_len)
486 		hfs_find_exit(&fd);
487 	return res;
488 }
489 
490 ssize_t __hfsplus_getxattr(struct inode *inode, const char *name,
491 			 void *value, size_t size)
492 {
493 	struct hfs_find_data fd;
494 	hfsplus_attr_entry *entry;
495 	__be32 xattr_record_type;
496 	u32 record_type;
497 	u16 record_length = 0;
498 	ssize_t res = 0;
499 
500 	if ((!S_ISREG(inode->i_mode) &&
501 			!S_ISDIR(inode->i_mode)) ||
502 				HFSPLUS_IS_RSRC(inode))
503 		return -EOPNOTSUPP;
504 
505 	if (!strcmp_xattr_finder_info(name))
506 		return hfsplus_getxattr_finder_info(inode, value, size);
507 
508 	if (!HFSPLUS_SB(inode->i_sb)->attr_tree)
509 		return -EOPNOTSUPP;
510 
511 	entry = hfsplus_alloc_attr_entry();
512 	if (!entry) {
513 		pr_err("can't allocate xattr entry\n");
514 		return -ENOMEM;
515 	}
516 
517 	res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->attr_tree, &fd);
518 	if (res) {
519 		pr_err("can't init xattr find struct\n");
520 		goto failed_getxattr_init;
521 	}
522 
523 	res = hfsplus_find_attr(inode->i_sb, inode->i_ino, name, &fd);
524 	if (res) {
525 		if (res == -ENOENT)
526 			res = -ENODATA;
527 		else
528 			pr_err("xattr searching failed\n");
529 		goto out;
530 	}
531 
532 	hfs_bnode_read(fd.bnode, &xattr_record_type,
533 			fd.entryoffset, sizeof(xattr_record_type));
534 	record_type = be32_to_cpu(xattr_record_type);
535 	if (record_type == HFSPLUS_ATTR_INLINE_DATA) {
536 		record_length = hfs_bnode_read_u16(fd.bnode,
537 				fd.entryoffset +
538 				offsetof(struct hfsplus_attr_inline_data,
539 				length));
540 		if (record_length > HFSPLUS_MAX_INLINE_DATA_SIZE) {
541 			pr_err("invalid xattr record size\n");
542 			res = -EIO;
543 			goto out;
544 		}
545 	} else if (record_type == HFSPLUS_ATTR_FORK_DATA ||
546 			record_type == HFSPLUS_ATTR_EXTENTS) {
547 		pr_err("only inline data xattr are supported\n");
548 		res = -EOPNOTSUPP;
549 		goto out;
550 	} else {
551 		pr_err("invalid xattr record\n");
552 		res = -EIO;
553 		goto out;
554 	}
555 
556 	if (size) {
557 		hfs_bnode_read(fd.bnode, entry, fd.entryoffset,
558 				offsetof(struct hfsplus_attr_inline_data,
559 					raw_bytes) + record_length);
560 	}
561 
562 	if (size >= record_length) {
563 		memcpy(value, entry->inline_data.raw_bytes, record_length);
564 		res = record_length;
565 	} else
566 		res = size ? -ERANGE : record_length;
567 
568 out:
569 	hfs_find_exit(&fd);
570 
571 failed_getxattr_init:
572 	hfsplus_destroy_attr_entry(entry);
573 	return res;
574 }
575 
576 ssize_t hfsplus_getxattr(struct inode *inode, const char *name,
577 			 void *value, size_t size,
578 			 const char *prefix, size_t prefixlen)
579 {
580 	int res;
581 	char *xattr_name;
582 
583 	xattr_name = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN + 1,
584 			     GFP_KERNEL);
585 	if (!xattr_name)
586 		return -ENOMEM;
587 
588 	strcpy(xattr_name, prefix);
589 	strcpy(xattr_name + prefixlen, name);
590 
591 	res = __hfsplus_getxattr(inode, xattr_name, value, size);
592 	kfree(xattr_name);
593 	return res;
594 
595 }
596 
597 static inline int can_list(const char *xattr_name)
598 {
599 	if (!xattr_name)
600 		return 0;
601 
602 	return strncmp(xattr_name, XATTR_TRUSTED_PREFIX,
603 			XATTR_TRUSTED_PREFIX_LEN) ||
604 				capable(CAP_SYS_ADMIN);
605 }
606 
607 static ssize_t hfsplus_listxattr_finder_info(struct dentry *dentry,
608 						char *buffer, size_t size)
609 {
610 	ssize_t res = 0;
611 	struct inode *inode = d_inode(dentry);
612 	struct hfs_find_data fd;
613 	u16 entry_type;
614 	u8 folder_finder_info[sizeof(struct DInfo) + sizeof(struct DXInfo)];
615 	u8 file_finder_info[sizeof(struct FInfo) + sizeof(struct FXInfo)];
616 	unsigned long len, found_bit;
617 	int xattr_name_len, symbols_count;
618 
619 	res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &fd);
620 	if (res) {
621 		pr_err("can't init xattr find struct\n");
622 		return res;
623 	}
624 
625 	res = hfsplus_find_cat(inode->i_sb, inode->i_ino, &fd);
626 	if (res)
627 		goto end_listxattr_finder_info;
628 
629 	entry_type = hfs_bnode_read_u16(fd.bnode, fd.entryoffset);
630 	if (entry_type == HFSPLUS_FOLDER) {
631 		len = sizeof(struct DInfo) + sizeof(struct DXInfo);
632 		hfs_bnode_read(fd.bnode, folder_finder_info,
633 				fd.entryoffset +
634 				offsetof(struct hfsplus_cat_folder, user_info),
635 				len);
636 		found_bit = find_first_bit((void *)folder_finder_info, len*8);
637 	} else if (entry_type == HFSPLUS_FILE) {
638 		len = sizeof(struct FInfo) + sizeof(struct FXInfo);
639 		hfs_bnode_read(fd.bnode, file_finder_info,
640 				fd.entryoffset +
641 				offsetof(struct hfsplus_cat_file, user_info),
642 				len);
643 		found_bit = find_first_bit((void *)file_finder_info, len*8);
644 	} else {
645 		res = -EOPNOTSUPP;
646 		goto end_listxattr_finder_info;
647 	}
648 
649 	if (found_bit >= (len*8))
650 		res = 0;
651 	else {
652 		symbols_count = sizeof(HFSPLUS_XATTR_FINDER_INFO_NAME) - 1;
653 		xattr_name_len =
654 			name_len(HFSPLUS_XATTR_FINDER_INFO_NAME, symbols_count);
655 		if (!buffer || !size) {
656 			if (can_list(HFSPLUS_XATTR_FINDER_INFO_NAME))
657 				res = xattr_name_len;
658 		} else if (can_list(HFSPLUS_XATTR_FINDER_INFO_NAME)) {
659 			if (size < xattr_name_len)
660 				res = -ERANGE;
661 			else {
662 				res = copy_name(buffer,
663 						HFSPLUS_XATTR_FINDER_INFO_NAME,
664 						symbols_count);
665 			}
666 		}
667 	}
668 
669 end_listxattr_finder_info:
670 	hfs_find_exit(&fd);
671 
672 	return res;
673 }
674 
675 ssize_t hfsplus_listxattr(struct dentry *dentry, char *buffer, size_t size)
676 {
677 	ssize_t err;
678 	ssize_t res = 0;
679 	struct inode *inode = d_inode(dentry);
680 	struct hfs_find_data fd;
681 	u16 key_len = 0;
682 	struct hfsplus_attr_key attr_key;
683 	char *strbuf;
684 	int xattr_name_len;
685 
686 	if ((!S_ISREG(inode->i_mode) &&
687 			!S_ISDIR(inode->i_mode)) ||
688 				HFSPLUS_IS_RSRC(inode))
689 		return -EOPNOTSUPP;
690 
691 	res = hfsplus_listxattr_finder_info(dentry, buffer, size);
692 	if (res < 0)
693 		return res;
694 	else if (!HFSPLUS_SB(inode->i_sb)->attr_tree)
695 		return (res == 0) ? -EOPNOTSUPP : res;
696 
697 	err = hfs_find_init(HFSPLUS_SB(inode->i_sb)->attr_tree, &fd);
698 	if (err) {
699 		pr_err("can't init xattr find struct\n");
700 		return err;
701 	}
702 
703 	strbuf = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN +
704 			XATTR_MAC_OSX_PREFIX_LEN + 1, GFP_KERNEL);
705 	if (!strbuf) {
706 		res = -ENOMEM;
707 		goto out;
708 	}
709 
710 	err = hfsplus_find_attr(inode->i_sb, inode->i_ino, NULL, &fd);
711 	if (err) {
712 		if (err == -ENOENT) {
713 			if (res == 0)
714 				res = -ENODATA;
715 			goto end_listxattr;
716 		} else {
717 			res = err;
718 			goto end_listxattr;
719 		}
720 	}
721 
722 	for (;;) {
723 		key_len = hfs_bnode_read_u16(fd.bnode, fd.keyoffset);
724 		if (key_len == 0 || key_len > fd.tree->max_key_len) {
725 			pr_err("invalid xattr key length: %d\n", key_len);
726 			res = -EIO;
727 			goto end_listxattr;
728 		}
729 
730 		hfs_bnode_read(fd.bnode, &attr_key,
731 				fd.keyoffset, key_len + sizeof(key_len));
732 
733 		if (be32_to_cpu(attr_key.cnid) != inode->i_ino)
734 			goto end_listxattr;
735 
736 		xattr_name_len = NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN;
737 		if (hfsplus_uni2asc(inode->i_sb,
738 			(const struct hfsplus_unistr *)&fd.key->attr.key_name,
739 					strbuf, &xattr_name_len)) {
740 			pr_err("unicode conversion failed\n");
741 			res = -EIO;
742 			goto end_listxattr;
743 		}
744 
745 		if (!buffer || !size) {
746 			if (can_list(strbuf))
747 				res += name_len(strbuf, xattr_name_len);
748 		} else if (can_list(strbuf)) {
749 			if (size < (res + name_len(strbuf, xattr_name_len))) {
750 				res = -ERANGE;
751 				goto end_listxattr;
752 			} else
753 				res += copy_name(buffer + res,
754 						strbuf, xattr_name_len);
755 		}
756 
757 		if (hfs_brec_goto(&fd, 1))
758 			goto end_listxattr;
759 	}
760 
761 end_listxattr:
762 	kfree(strbuf);
763 out:
764 	hfs_find_exit(&fd);
765 	return res;
766 }
767 
768 static int hfsplus_removexattr(struct inode *inode, const char *name)
769 {
770 	int err = 0;
771 	struct hfs_find_data cat_fd;
772 	u16 flags;
773 	u16 cat_entry_type;
774 	int is_xattr_acl_deleted = 0;
775 	int is_all_xattrs_deleted = 0;
776 
777 	if (!HFSPLUS_SB(inode->i_sb)->attr_tree)
778 		return -EOPNOTSUPP;
779 
780 	if (!strcmp_xattr_finder_info(name))
781 		return -EOPNOTSUPP;
782 
783 	err = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &cat_fd);
784 	if (err) {
785 		pr_err("can't init xattr find struct\n");
786 		return err;
787 	}
788 
789 	err = hfsplus_find_cat(inode->i_sb, inode->i_ino, &cat_fd);
790 	if (err) {
791 		pr_err("catalog searching failed\n");
792 		goto end_removexattr;
793 	}
794 
795 	err = hfsplus_delete_attr(inode, name);
796 	if (err)
797 		goto end_removexattr;
798 
799 	is_xattr_acl_deleted = !strcmp_xattr_acl(name);
800 	is_all_xattrs_deleted = !hfsplus_attr_exists(inode, NULL);
801 
802 	if (!is_xattr_acl_deleted && !is_all_xattrs_deleted)
803 		goto end_removexattr;
804 
805 	cat_entry_type = hfs_bnode_read_u16(cat_fd.bnode, cat_fd.entryoffset);
806 
807 	if (cat_entry_type == HFSPLUS_FOLDER) {
808 		flags = hfs_bnode_read_u16(cat_fd.bnode, cat_fd.entryoffset +
809 				offsetof(struct hfsplus_cat_folder, flags));
810 		if (is_xattr_acl_deleted)
811 			flags &= ~HFSPLUS_ACL_EXISTS;
812 		if (is_all_xattrs_deleted)
813 			flags &= ~HFSPLUS_XATTR_EXISTS;
814 		hfs_bnode_write_u16(cat_fd.bnode, cat_fd.entryoffset +
815 				offsetof(struct hfsplus_cat_folder, flags),
816 				flags);
817 		hfsplus_mark_inode_dirty(inode, HFSPLUS_I_CAT_DIRTY);
818 	} else if (cat_entry_type == HFSPLUS_FILE) {
819 		flags = hfs_bnode_read_u16(cat_fd.bnode, cat_fd.entryoffset +
820 				offsetof(struct hfsplus_cat_file, flags));
821 		if (is_xattr_acl_deleted)
822 			flags &= ~HFSPLUS_ACL_EXISTS;
823 		if (is_all_xattrs_deleted)
824 			flags &= ~HFSPLUS_XATTR_EXISTS;
825 		hfs_bnode_write_u16(cat_fd.bnode, cat_fd.entryoffset +
826 				offsetof(struct hfsplus_cat_file, flags),
827 				flags);
828 		hfsplus_mark_inode_dirty(inode, HFSPLUS_I_CAT_DIRTY);
829 	} else {
830 		pr_err("invalid catalog entry type\n");
831 		err = -EIO;
832 		goto end_removexattr;
833 	}
834 
835 end_removexattr:
836 	hfs_find_exit(&cat_fd);
837 	return err;
838 }
839 
840 static int hfsplus_osx_getxattr(const struct xattr_handler *handler,
841 				struct dentry *unused, struct inode *inode,
842 				const char *name, void *buffer, size_t size)
843 {
844 	/*
845 	 * Don't allow retrieving properly prefixed attributes
846 	 * by prepending them with "osx."
847 	 */
848 	if (is_known_namespace(name))
849 		return -EOPNOTSUPP;
850 
851 	/*
852 	 * osx is the namespace we use to indicate an unprefixed
853 	 * attribute on the filesystem (like the ones that OS X
854 	 * creates), so we pass the name through unmodified (after
855 	 * ensuring it doesn't conflict with another namespace).
856 	 */
857 	return __hfsplus_getxattr(inode, name, buffer, size);
858 }
859 
860 static int hfsplus_osx_setxattr(const struct xattr_handler *handler,
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