xref: /linux/fs/hfsplus/xattr.c (revision b3e1c7855e8e1c4d77685ce4a8cd9cdd576058eb)
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 
strcmp_xattr_finder_info(const char * name)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 
strcmp_xattr_acl(const char * name)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 
is_known_namespace(const char * name)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 
hfsplus_init_header_node(struct inode * attr_file,u32 clump_size,char * buf,u16 node_size)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 
hfsplus_create_attributes_file(struct super_block * sb)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 
__hfsplus_setxattr(struct inode * inode,const char * name,const void * value,size_t size,int flags)261 int __hfsplus_setxattr(struct inode *inode, const char *name,
262 			const void *value, size_t size, int flags)
263 {
264 	int err;
265 	struct hfs_find_data cat_fd;
266 	hfsplus_cat_entry entry;
267 	u16 cat_entry_flags, cat_entry_type;
268 	u16 folder_finderinfo_len = sizeof(struct DInfo) +
269 					sizeof(struct DXInfo);
270 	u16 file_finderinfo_len = sizeof(struct FInfo) +
271 					sizeof(struct FXInfo);
272 
273 	if ((!S_ISREG(inode->i_mode) &&
274 			!S_ISDIR(inode->i_mode)) ||
275 				HFSPLUS_IS_RSRC(inode))
276 		return -EOPNOTSUPP;
277 
278 	if (value == NULL)
279 		return hfsplus_removexattr(inode, name);
280 
281 	err = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &cat_fd);
282 	if (err) {
283 		pr_err("can't init xattr find struct\n");
284 		return err;
285 	}
286 
287 	err = hfsplus_find_cat(inode->i_sb, inode->i_ino, &cat_fd);
288 	if (err) {
289 		pr_err("catalog searching failed\n");
290 		goto end_setxattr;
291 	}
292 
293 	if (!strcmp_xattr_finder_info(name)) {
294 		if (flags & XATTR_CREATE) {
295 			pr_err("xattr exists yet\n");
296 			err = -EOPNOTSUPP;
297 			goto end_setxattr;
298 		}
299 		hfs_bnode_read(cat_fd.bnode, &entry, cat_fd.entryoffset,
300 					sizeof(hfsplus_cat_entry));
301 		if (be16_to_cpu(entry.type) == HFSPLUS_FOLDER) {
302 			if (size == folder_finderinfo_len) {
303 				memcpy(&entry.folder.info, value,
304 						folder_finderinfo_len);
305 				hfs_bnode_write(cat_fd.bnode, &entry,
306 					cat_fd.entryoffset,
307 					sizeof(struct hfsplus_cat_folder));
308 				hfsplus_mark_inode_dirty(inode,
309 						HFSPLUS_I_CAT_DIRTY);
310 			} else {
311 				err = -ERANGE;
312 				goto end_setxattr;
313 			}
314 		} else if (be16_to_cpu(entry.type) == HFSPLUS_FILE) {
315 			if (size == file_finderinfo_len) {
316 				memcpy(&entry.file.info, value,
317 						file_finderinfo_len);
318 				hfs_bnode_write(cat_fd.bnode, &entry,
319 					cat_fd.entryoffset,
320 					sizeof(struct hfsplus_cat_file));
321 				hfsplus_mark_inode_dirty(inode,
322 						HFSPLUS_I_CAT_DIRTY);
323 			} else {
324 				err = -ERANGE;
325 				goto end_setxattr;
326 			}
327 		} else {
328 			err = -EOPNOTSUPP;
329 			goto end_setxattr;
330 		}
331 		goto end_setxattr;
332 	}
333 
334 	if (!HFSPLUS_SB(inode->i_sb)->attr_tree) {
335 		err = hfsplus_create_attributes_file(inode->i_sb);
336 		if (unlikely(err))
337 			goto end_setxattr;
338 	}
339 
340 	if (hfsplus_attr_exists(inode, name)) {
341 		if (flags & XATTR_CREATE) {
342 			pr_err("xattr exists yet\n");
343 			err = -EOPNOTSUPP;
344 			goto end_setxattr;
345 		}
346 		err = hfsplus_delete_attr(inode, name);
347 		if (err)
348 			goto end_setxattr;
349 		err = hfsplus_create_attr(inode, name, value, size);
350 		if (err)
351 			goto end_setxattr;
352 	} else {
353 		if (flags & XATTR_REPLACE) {
354 			pr_err("cannot replace xattr\n");
355 			err = -EOPNOTSUPP;
356 			goto end_setxattr;
357 		}
358 		err = hfsplus_create_attr(inode, name, value, size);
359 		if (err)
360 			goto end_setxattr;
361 	}
362 
363 	cat_entry_type = hfs_bnode_read_u16(cat_fd.bnode, cat_fd.entryoffset);
364 	if (cat_entry_type == HFSPLUS_FOLDER) {
365 		cat_entry_flags = hfs_bnode_read_u16(cat_fd.bnode,
366 				    cat_fd.entryoffset +
367 				    offsetof(struct hfsplus_cat_folder, flags));
368 		cat_entry_flags |= HFSPLUS_XATTR_EXISTS;
369 		if (!strcmp_xattr_acl(name))
370 			cat_entry_flags |= HFSPLUS_ACL_EXISTS;
371 		hfs_bnode_write_u16(cat_fd.bnode, cat_fd.entryoffset +
372 				offsetof(struct hfsplus_cat_folder, flags),
373 				cat_entry_flags);
374 		hfsplus_mark_inode_dirty(inode, HFSPLUS_I_CAT_DIRTY);
375 	} else if (cat_entry_type == HFSPLUS_FILE) {
376 		cat_entry_flags = hfs_bnode_read_u16(cat_fd.bnode,
377 				    cat_fd.entryoffset +
378 				    offsetof(struct hfsplus_cat_file, flags));
379 		cat_entry_flags |= HFSPLUS_XATTR_EXISTS;
380 		if (!strcmp_xattr_acl(name))
381 			cat_entry_flags |= HFSPLUS_ACL_EXISTS;
382 		hfs_bnode_write_u16(cat_fd.bnode, cat_fd.entryoffset +
383 				    offsetof(struct hfsplus_cat_file, flags),
384 				    cat_entry_flags);
385 		hfsplus_mark_inode_dirty(inode, HFSPLUS_I_CAT_DIRTY);
386 	} else {
387 		pr_err("invalid catalog entry type\n");
388 		err = -EIO;
389 		goto end_setxattr;
390 	}
391 
392 end_setxattr:
393 	hfs_find_exit(&cat_fd);
394 	return err;
395 }
396 
name_len(const char * xattr_name,int xattr_name_len)397 static int name_len(const char *xattr_name, int xattr_name_len)
398 {
399 	int len = xattr_name_len + 1;
400 
401 	if (!is_known_namespace(xattr_name))
402 		len += XATTR_MAC_OSX_PREFIX_LEN;
403 
404 	return len;
405 }
406 
copy_name(char * buffer,const char * xattr_name,int name_len)407 static ssize_t copy_name(char *buffer, const char *xattr_name, int name_len)
408 {
409 	ssize_t len;
410 
411 	if (!is_known_namespace(xattr_name))
412 		len = scnprintf(buffer, name_len + XATTR_MAC_OSX_PREFIX_LEN,
413 				 "%s%s", XATTR_MAC_OSX_PREFIX, xattr_name);
414 	else
415 		len = strscpy(buffer, xattr_name, name_len + 1);
416 
417 	/* include NUL-byte in length for non-empty name */
418 	if (len >= 0)
419 		len++;
420 	return len;
421 }
422 
hfsplus_setxattr(struct inode * inode,const char * name,const void * value,size_t size,int flags,const char * prefix,size_t prefixlen)423 int hfsplus_setxattr(struct inode *inode, const char *name,
424 		     const void *value, size_t size, int flags,
425 		     const char *prefix, size_t prefixlen)
426 {
427 	char *xattr_name;
428 	int res;
429 
430 	xattr_name = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN + 1,
431 		GFP_KERNEL);
432 	if (!xattr_name)
433 		return -ENOMEM;
434 	strcpy(xattr_name, prefix);
435 	strcpy(xattr_name + prefixlen, name);
436 	res = __hfsplus_setxattr(inode, xattr_name, value, size, flags);
437 	kfree(xattr_name);
438 	return res;
439 }
440 
hfsplus_getxattr_finder_info(struct inode * inode,void * value,size_t size)441 static ssize_t hfsplus_getxattr_finder_info(struct inode *inode,
442 						void *value, size_t size)
443 {
444 	ssize_t res = 0;
445 	struct hfs_find_data fd;
446 	u16 entry_type;
447 	u16 folder_rec_len = sizeof(struct DInfo) + sizeof(struct DXInfo);
448 	u16 file_rec_len = sizeof(struct FInfo) + sizeof(struct FXInfo);
449 	u16 record_len = max(folder_rec_len, file_rec_len);
450 	u8 folder_finder_info[sizeof(struct DInfo) + sizeof(struct DXInfo)];
451 	u8 file_finder_info[sizeof(struct FInfo) + sizeof(struct FXInfo)];
452 
453 	if (size >= record_len) {
454 		res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &fd);
455 		if (res) {
456 			pr_err("can't init xattr find struct\n");
457 			return res;
458 		}
459 		res = hfsplus_find_cat(inode->i_sb, inode->i_ino, &fd);
460 		if (res)
461 			goto end_getxattr_finder_info;
462 		entry_type = hfs_bnode_read_u16(fd.bnode, fd.entryoffset);
463 
464 		if (entry_type == HFSPLUS_FOLDER) {
465 			hfs_bnode_read(fd.bnode, folder_finder_info,
466 				fd.entryoffset +
467 				offsetof(struct hfsplus_cat_folder, user_info),
468 				folder_rec_len);
469 			memcpy(value, folder_finder_info, folder_rec_len);
470 			res = folder_rec_len;
471 		} else if (entry_type == HFSPLUS_FILE) {
472 			hfs_bnode_read(fd.bnode, file_finder_info,
473 				fd.entryoffset +
474 				offsetof(struct hfsplus_cat_file, user_info),
475 				file_rec_len);
476 			memcpy(value, file_finder_info, file_rec_len);
477 			res = file_rec_len;
478 		} else {
479 			res = -EOPNOTSUPP;
480 			goto end_getxattr_finder_info;
481 		}
482 	} else
483 		res = size ? -ERANGE : record_len;
484 
485 end_getxattr_finder_info:
486 	if (size >= record_len)
487 		hfs_find_exit(&fd);
488 	return res;
489 }
490 
__hfsplus_getxattr(struct inode * inode,const char * name,void * value,size_t size)491 ssize_t __hfsplus_getxattr(struct inode *inode, const char *name,
492 			 void *value, size_t size)
493 {
494 	struct hfs_find_data fd;
495 	hfsplus_attr_entry *entry;
496 	__be32 xattr_record_type;
497 	u32 record_type;
498 	u16 record_length = 0;
499 	ssize_t res;
500 
501 	if ((!S_ISREG(inode->i_mode) &&
502 			!S_ISDIR(inode->i_mode)) ||
503 				HFSPLUS_IS_RSRC(inode))
504 		return -EOPNOTSUPP;
505 
506 	if (!strcmp_xattr_finder_info(name))
507 		return hfsplus_getxattr_finder_info(inode, value, size);
508 
509 	if (!HFSPLUS_SB(inode->i_sb)->attr_tree)
510 		return -EOPNOTSUPP;
511 
512 	entry = hfsplus_alloc_attr_entry();
513 	if (!entry) {
514 		pr_err("can't allocate xattr entry\n");
515 		return -ENOMEM;
516 	}
517 
518 	res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->attr_tree, &fd);
519 	if (res) {
520 		pr_err("can't init xattr find struct\n");
521 		goto failed_getxattr_init;
522 	}
523 
524 	res = hfsplus_find_attr(inode->i_sb, inode->i_ino, name, &fd);
525 	if (res) {
526 		if (res == -ENOENT)
527 			res = -ENODATA;
528 		else
529 			pr_err("xattr searching failed\n");
530 		goto out;
531 	}
532 
533 	hfs_bnode_read(fd.bnode, &xattr_record_type,
534 			fd.entryoffset, sizeof(xattr_record_type));
535 	record_type = be32_to_cpu(xattr_record_type);
536 	if (record_type == HFSPLUS_ATTR_INLINE_DATA) {
537 		record_length = hfs_bnode_read_u16(fd.bnode,
538 				fd.entryoffset +
539 				offsetof(struct hfsplus_attr_inline_data,
540 				length));
541 		if (record_length > HFSPLUS_MAX_INLINE_DATA_SIZE) {
542 			pr_err("invalid xattr record size\n");
543 			res = -EIO;
544 			goto out;
545 		}
546 	} else if (record_type == HFSPLUS_ATTR_FORK_DATA ||
547 			record_type == HFSPLUS_ATTR_EXTENTS) {
548 		pr_err("only inline data xattr are supported\n");
549 		res = -EOPNOTSUPP;
550 		goto out;
551 	} else {
552 		pr_err("invalid xattr record\n");
553 		res = -EIO;
554 		goto out;
555 	}
556 
557 	if (size) {
558 		hfs_bnode_read(fd.bnode, entry, fd.entryoffset,
559 				offsetof(struct hfsplus_attr_inline_data,
560 					raw_bytes) + record_length);
561 	}
562 
563 	if (size >= record_length) {
564 		memcpy(value, entry->inline_data.raw_bytes, record_length);
565 		res = record_length;
566 	} else
567 		res = size ? -ERANGE : record_length;
568 
569 out:
570 	hfs_find_exit(&fd);
571 
572 failed_getxattr_init:
573 	hfsplus_destroy_attr_entry(entry);
574 	return res;
575 }
576 
hfsplus_getxattr(struct inode * inode,const char * name,void * value,size_t size,const char * prefix,size_t prefixlen)577 ssize_t hfsplus_getxattr(struct inode *inode, const char *name,
578 			 void *value, size_t size,
579 			 const char *prefix, size_t prefixlen)
580 {
581 	int res;
582 	char *xattr_name;
583 
584 	xattr_name = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN + 1,
585 			     GFP_KERNEL);
586 	if (!xattr_name)
587 		return -ENOMEM;
588 
589 	strcpy(xattr_name, prefix);
590 	strcpy(xattr_name + prefixlen, name);
591 
592 	res = __hfsplus_getxattr(inode, xattr_name, value, size);
593 	kfree(xattr_name);
594 	return res;
595 
596 }
597 
can_list(const char * xattr_name)598 static inline int can_list(const char *xattr_name)
599 {
600 	if (!xattr_name)
601 		return 0;
602 
603 	return strncmp(xattr_name, XATTR_TRUSTED_PREFIX,
604 			XATTR_TRUSTED_PREFIX_LEN) ||
605 				capable(CAP_SYS_ADMIN);
606 }
607 
hfsplus_listxattr_finder_info(struct dentry * dentry,char * buffer,size_t size)608 static ssize_t hfsplus_listxattr_finder_info(struct dentry *dentry,
609 						char *buffer, size_t size)
610 {
611 	ssize_t res;
612 	struct inode *inode = d_inode(dentry);
613 	struct hfs_find_data fd;
614 	u16 entry_type;
615 	u8 folder_finder_info[sizeof(struct DInfo) + sizeof(struct DXInfo)];
616 	u8 file_finder_info[sizeof(struct FInfo) + sizeof(struct FXInfo)];
617 	unsigned long len, found_bit;
618 	int xattr_name_len, symbols_count;
619 
620 	res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &fd);
621 	if (res) {
622 		pr_err("can't init xattr find struct\n");
623 		return res;
624 	}
625 
626 	res = hfsplus_find_cat(inode->i_sb, inode->i_ino, &fd);
627 	if (res)
628 		goto end_listxattr_finder_info;
629 
630 	entry_type = hfs_bnode_read_u16(fd.bnode, fd.entryoffset);
631 	if (entry_type == HFSPLUS_FOLDER) {
632 		len = sizeof(struct DInfo) + sizeof(struct DXInfo);
633 		hfs_bnode_read(fd.bnode, folder_finder_info,
634 				fd.entryoffset +
635 				offsetof(struct hfsplus_cat_folder, user_info),
636 				len);
637 		found_bit = find_first_bit((void *)folder_finder_info, len*8);
638 	} else if (entry_type == HFSPLUS_FILE) {
639 		len = sizeof(struct FInfo) + sizeof(struct FXInfo);
640 		hfs_bnode_read(fd.bnode, file_finder_info,
641 				fd.entryoffset +
642 				offsetof(struct hfsplus_cat_file, user_info),
643 				len);
644 		found_bit = find_first_bit((void *)file_finder_info, len*8);
645 	} else {
646 		res = -EOPNOTSUPP;
647 		goto end_listxattr_finder_info;
648 	}
649 
650 	if (found_bit >= (len*8))
651 		res = 0;
652 	else {
653 		symbols_count = sizeof(HFSPLUS_XATTR_FINDER_INFO_NAME) - 1;
654 		xattr_name_len =
655 			name_len(HFSPLUS_XATTR_FINDER_INFO_NAME, symbols_count);
656 		if (!buffer || !size) {
657 			if (can_list(HFSPLUS_XATTR_FINDER_INFO_NAME))
658 				res = xattr_name_len;
659 		} else if (can_list(HFSPLUS_XATTR_FINDER_INFO_NAME)) {
660 			if (size < xattr_name_len)
661 				res = -ERANGE;
662 			else {
663 				res = copy_name(buffer,
664 						HFSPLUS_XATTR_FINDER_INFO_NAME,
665 						symbols_count);
666 			}
667 		}
668 	}
669 
670 end_listxattr_finder_info:
671 	hfs_find_exit(&fd);
672 
673 	return res;
674 }
675 
hfsplus_listxattr(struct dentry * dentry,char * buffer,size_t size)676 ssize_t hfsplus_listxattr(struct dentry *dentry, char *buffer, size_t size)
677 {
678 	ssize_t err;
679 	ssize_t res;
680 	struct inode *inode = d_inode(dentry);
681 	struct hfs_find_data fd;
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 = kzalloc(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 		u16 key_len = hfs_bnode_read_u16(fd.bnode, fd.keyoffset);
724 
725 		if (key_len == 0 || key_len > fd.tree->max_key_len) {
726 			pr_err("invalid xattr key length: %d\n", key_len);
727 			res = -EIO;
728 			goto end_listxattr;
729 		}
730 
731 		hfs_bnode_read(fd.bnode, &attr_key,
732 				fd.keyoffset, key_len + sizeof(key_len));
733 
734 		if (be32_to_cpu(attr_key.cnid) != inode->i_ino)
735 			goto end_listxattr;
736 
737 		xattr_name_len = NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN;
738 		if (hfsplus_uni2asc_xattr_str(inode->i_sb,
739 					      &fd.key->attr.key_name, strbuf,
740 					      &xattr_name_len)) {
741 			pr_err("unicode conversion failed\n");
742 			res = -EIO;
743 			goto end_listxattr;
744 		}
745 
746 		if (!buffer || !size) {
747 			if (can_list(strbuf))
748 				res += name_len(strbuf, xattr_name_len);
749 		} else if (can_list(strbuf)) {
750 			if (size < (res + name_len(strbuf, xattr_name_len))) {
751 				res = -ERANGE;
752 				goto end_listxattr;
753 			} else
754 				res += copy_name(buffer + res,
755 						strbuf, xattr_name_len);
756 		}
757 
758 		if (hfs_brec_goto(&fd, 1))
759 			goto end_listxattr;
760 	}
761 
762 end_listxattr:
763 	kfree(strbuf);
764 out:
765 	hfs_find_exit(&fd);
766 	return res;
767 }
768 
hfsplus_removexattr(struct inode * inode,const char * name)769 static int hfsplus_removexattr(struct inode *inode, const char *name)
770 {
771 	int err;
772 	struct hfs_find_data cat_fd;
773 	u16 flags;
774 	u16 cat_entry_type;
775 	int is_xattr_acl_deleted;
776 	int is_all_xattrs_deleted;
777 
778 	if (!HFSPLUS_SB(inode->i_sb)->attr_tree)
779 		return -EOPNOTSUPP;
780 
781 	if (!strcmp_xattr_finder_info(name))
782 		return -EOPNOTSUPP;
783 
784 	err = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &cat_fd);
785 	if (err) {
786 		pr_err("can't init xattr find struct\n");
787 		return err;
788 	}
789 
790 	err = hfsplus_find_cat(inode->i_sb, inode->i_ino, &cat_fd);
791 	if (err) {
792 		pr_err("catalog searching failed\n");
793 		goto end_removexattr;
794 	}
795 
796 	err = hfsplus_delete_attr(inode, name);
797 	if (err)
798 		goto end_removexattr;
799 
800 	is_xattr_acl_deleted = !strcmp_xattr_acl(name);
801 	is_all_xattrs_deleted = !hfsplus_attr_exists(inode, NULL);
802 
803 	if (!is_xattr_acl_deleted && !is_all_xattrs_deleted)
804 		goto end_removexattr;
805 
806 	cat_entry_type = hfs_bnode_read_u16(cat_fd.bnode, cat_fd.entryoffset);
807 
808 	if (cat_entry_type == HFSPLUS_FOLDER) {
809 		flags = hfs_bnode_read_u16(cat_fd.bnode, cat_fd.entryoffset +
810 				offsetof(struct hfsplus_cat_folder, flags));
811 		if (is_xattr_acl_deleted)
812 			flags &= ~HFSPLUS_ACL_EXISTS;
813 		if (is_all_xattrs_deleted)
814 			flags &= ~HFSPLUS_XATTR_EXISTS;
815 		hfs_bnode_write_u16(cat_fd.bnode, cat_fd.entryoffset +
816 				offsetof(struct hfsplus_cat_folder, flags),
817 				flags);
818 		hfsplus_mark_inode_dirty(inode, HFSPLUS_I_CAT_DIRTY);
819 	} else if (cat_entry_type == HFSPLUS_FILE) {
820 		flags = hfs_bnode_read_u16(cat_fd.bnode, cat_fd.entryoffset +
821 				offsetof(struct hfsplus_cat_file, flags));
822 		if (is_xattr_acl_deleted)
823 			flags &= ~HFSPLUS_ACL_EXISTS;
824 		if (is_all_xattrs_deleted)
825 			flags &= ~HFSPLUS_XATTR_EXISTS;
826 		hfs_bnode_write_u16(cat_fd.bnode, cat_fd.entryoffset +
827 				offsetof(struct hfsplus_cat_file, flags),
828 				flags);
829 		hfsplus_mark_inode_dirty(inode, HFSPLUS_I_CAT_DIRTY);
830 	} else {
831 		pr_err("invalid catalog entry type\n");
832 		err = -EIO;
833 		goto end_removexattr;
834 	}
835 
836 end_removexattr:
837 	hfs_find_exit(&cat_fd);
838 	return err;
839 }
840 
hfsplus_osx_getxattr(const struct xattr_handler * handler,struct dentry * unused,struct inode * inode,const char * name,void * buffer,size_t size)841 static int hfsplus_osx_getxattr(const struct xattr_handler *handler,
842 				struct dentry *unused, struct inode *inode,
843 				const char *name, void *buffer, size_t size)
844 {
845 	/*
846 	 * Don't allow retrieving properly prefixed attributes
847 	 * by prepending them with "osx."
848 	 */
849 	if (is_known_namespace(name))
850 		return -EOPNOTSUPP;
851 
852 	/*
853 	 * osx is the namespace we use to indicate an unprefixed
854 	 * attribute on the filesystem (like the ones that OS X
855 	 * creates), so we pass the name through unmodified (after
856 	 * ensuring it doesn't conflict with another namespace).
857 	 */
858 	return __hfsplus_getxattr(inode, name, buffer, size);
859 }
860 
hfsplus_osx_setxattr(const struct xattr_handler * handler,struct mnt_idmap * idmap,struct dentry * unused,struct inode * inode,const char * name,const void * buffer,size_t size,int flags)861 static int hfsplus_osx_setxattr(const struct xattr_handler *handler,
862 				struct mnt_idmap *idmap,
863 				struct dentry *unused, struct inode *inode,
864 				const char *name, const void *buffer,
865 				size_t size, int flags)
866 {
867 	/*
868 	 * Don't allow setting properly prefixed attributes
869 	 * by prepending them with "osx."
870 	 */
871 	if (is_known_namespace(name))
872 		return -EOPNOTSUPP;
873 
874 	/*
875 	 * osx is the namespace we use to indicate an unprefixed
876 	 * attribute on the filesystem (like the ones that OS X
877 	 * creates), so we pass the name through unmodified (after
878 	 * ensuring it doesn't conflict with another namespace).
879 	 */
880 	return __hfsplus_setxattr(inode, name, buffer, size, flags);
881 }
882 
883 const struct xattr_handler hfsplus_xattr_osx_handler = {
884 	.prefix	= XATTR_MAC_OSX_PREFIX,
885 	.get	= hfsplus_osx_getxattr,
886 	.set	= hfsplus_osx_setxattr,
887 };
888