xref: /linux/fs/ntfs3/xattr.c (revision 7255fcc80d4b525cc10cfaaf7f485830d4ed2000) 
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *
4  * Copyright (C) 2019-2021 Paragon Software GmbH, All rights reserved.
5  *
6  */
7 
8 #include <linux/fs.h>
9 #include <linux/posix_acl.h>
10 #include <linux/posix_acl_xattr.h>
11 #include <linux/xattr.h>
12 
13 #include "debug.h"
14 #include "ntfs.h"
15 #include "ntfs_fs.h"
16 
17 // clang-format off
18 #define SYSTEM_DOS_ATTRIB     "system.dos_attrib"
19 #define SYSTEM_NTFS_ATTRIB    "system.ntfs_attrib"
20 #define SYSTEM_NTFS_ATTRIB_BE "system.ntfs_attrib_be"
21 #define SYSTEM_NTFS_SECURITY  "system.ntfs_security"
22 // clang-format on
23 
24 static inline size_t unpacked_ea_size(const struct EA_FULL *ea)
25 {
26 	return ea->size ? le32_to_cpu(ea->size) :
27 			  ALIGN(struct_size(ea, name,
28 					    1 + ea->name_len +
29 						    le16_to_cpu(ea->elength)),
30 				4);
31 }
32 
33 static inline size_t packed_ea_size(const struct EA_FULL *ea)
34 {
35 	return struct_size(ea, name,
36 			   1 + ea->name_len + le16_to_cpu(ea->elength)) -
37 	       offsetof(struct EA_FULL, flags);
38 }
39 
40 /*
41  * find_ea
42  *
43  * Assume there is at least one xattr in the list.
44  */
45 static inline bool find_ea(const struct EA_FULL *ea_all, u32 bytes,
46 			   const char *name, u8 name_len, u32 *off, u32 *ea_sz)
47 {
48 	u32 ea_size;
49 
50 	*off = 0;
51 	if (!ea_all)
52 		return false;
53 
54 	for (; *off < bytes; *off += ea_size) {
55 		const struct EA_FULL *ea = Add2Ptr(ea_all, *off);
56 		ea_size = unpacked_ea_size(ea);
57 		if (ea->name_len == name_len &&
58 		    !memcmp(ea->name, name, name_len)) {
59 			if (ea_sz)
60 				*ea_sz = ea_size;
61 			return true;
62 		}
63 	}
64 
65 	return false;
66 }
67 
68 /*
69  * ntfs_read_ea - Read all extended attributes.
70  * @ea:		New allocated memory.
71  * @info:	Pointer into resident data.
72  */
73 static int ntfs_read_ea(struct ntfs_inode *ni, struct EA_FULL **ea,
74 			size_t add_bytes, const struct EA_INFO **info)
75 {
76 	int err = -EINVAL;
77 	struct ntfs_sb_info *sbi = ni->mi.sbi;
78 	struct ATTR_LIST_ENTRY *le = NULL;
79 	struct ATTRIB *attr_info, *attr_ea;
80 	void *ea_p;
81 	u32 size, off, ea_size;
82 
83 	static_assert(le32_to_cpu(ATTR_EA_INFO) < le32_to_cpu(ATTR_EA));
84 
85 	*ea = NULL;
86 	*info = NULL;
87 
88 	attr_info =
89 		ni_find_attr(ni, NULL, &le, ATTR_EA_INFO, NULL, 0, NULL, NULL);
90 	attr_ea =
91 		ni_find_attr(ni, attr_info, &le, ATTR_EA, NULL, 0, NULL, NULL);
92 
93 	if (!attr_ea || !attr_info)
94 		return 0;
95 
96 	*info = resident_data_ex(attr_info, sizeof(struct EA_INFO));
97 	if (!*info)
98 		goto out;
99 
100 	/* Check Ea limit. */
101 	size = le32_to_cpu((*info)->size);
102 	if (size > sbi->ea_max_size) {
103 		err = -EFBIG;
104 		goto out;
105 	}
106 
107 	if (attr_size(attr_ea) > sbi->ea_max_size) {
108 		err = -EFBIG;
109 		goto out;
110 	}
111 
112 	if (!size) {
113 		/* EA info persists, but xattr is empty. Looks like EA problem. */
114 		goto out;
115 	}
116 
117 	/* Allocate memory for packed Ea. */
118 	ea_p = kmalloc(size_add(size, add_bytes), GFP_NOFS);
119 	if (!ea_p)
120 		return -ENOMEM;
121 
122 	if (attr_ea->non_res) {
123 		struct runs_tree run;
124 
125 		run_init(&run);
126 
127 		err = attr_load_runs_range(ni, ATTR_EA, NULL, 0, &run, 0, size);
128 		if (!err)
129 			err = ntfs_read_run_nb(sbi, &run, 0, ea_p, size, NULL);
130 		run_close(&run);
131 
132 		if (err)
133 			goto out1;
134 	} else {
135 		void *p = resident_data_ex(attr_ea, size);
136 
137 		if (!p)
138 			goto out1;
139 		memcpy(ea_p, p, size);
140 	}
141 
142 	memset(Add2Ptr(ea_p, size), 0, add_bytes);
143 
144 	err = -EINVAL;
145 	/* Check all attributes for consistency. */
146 	for (off = 0; off < size; off += ea_size) {
147 		const struct EA_FULL *ef = Add2Ptr(ea_p, off);
148 		u32 bytes = size - off;
149 
150 		/* Check if we can use field ea->size. */
151 		if (bytes < sizeof(ef->size))
152 			goto out1;
153 
154 		if (ef->size) {
155 			ea_size = le32_to_cpu(ef->size);
156 			if (ea_size > bytes)
157 				goto out1;
158 			continue;
159 		}
160 
161 		/* Check if we can use fields ef->name_len and ef->elength. */
162 		if (bytes < offsetof(struct EA_FULL, name))
163 			goto out1;
164 
165 		ea_size = ALIGN(struct_size(ef, name,
166 					    1 + ef->name_len +
167 						    le16_to_cpu(ef->elength)),
168 				4);
169 		if (ea_size > bytes)
170 			goto out1;
171 	}
172 
173 	*ea = ea_p;
174 	return 0;
175 
176 out1:
177 	kfree(ea_p);
178 out:
179 	ntfs_set_state(sbi, NTFS_DIRTY_DIRTY);
180 	return err;
181 }
182 
183 /*
184  * ntfs_list_ea
185  *
186  * Copy a list of xattrs names into the buffer
187  * provided, or compute the buffer size required.
188  *
189  * Return:
190  * * Number of bytes used / required on
191  * * -ERRNO - on failure
192  */
193 static ssize_t ntfs_list_ea(struct ntfs_inode *ni, char *buffer,
194 			    size_t bytes_per_buffer)
195 {
196 	const struct EA_INFO *info;
197 	struct EA_FULL *ea_all = NULL;
198 	const struct EA_FULL *ea;
199 	u32 off, size;
200 	int err;
201 	int ea_size;
202 	size_t ret;
203 
204 	err = ntfs_read_ea(ni, &ea_all, 0, &info);
205 	if (err)
206 		return err;
207 
208 	if (!info || !ea_all)
209 		return 0;
210 
211 	size = le32_to_cpu(info->size);
212 
213 	/* Enumerate all xattrs. */
214 	ret = 0;
215 	for (off = 0; off + sizeof(struct EA_FULL) < size; off += ea_size) {
216 		ea = Add2Ptr(ea_all, off);
217 		ea_size = unpacked_ea_size(ea);
218 
219 		if (!ea->name_len)
220 			break;
221 
222 		if (ea->name_len > ea_size)
223 			break;
224 
225 		if (buffer) {
226 			/* Check if we can use field ea->name */
227 			if (off + ea_size > size)
228 				break;
229 
230 			if (ret + ea->name_len + 1 > bytes_per_buffer) {
231 				err = -ERANGE;
232 				goto out;
233 			}
234 
235 			memcpy(buffer + ret, ea->name, ea->name_len);
236 			buffer[ret + ea->name_len] = 0;
237 		}
238 
239 		ret += ea->name_len + 1;
240 	}
241 
242 out:
243 	kfree(ea_all);
244 	return err ? err : ret;
245 }
246 
247 static int ntfs_get_ea(struct inode *inode, const char *name, size_t name_len,
248 		       void *buffer, size_t size, size_t *required)
249 {
250 	struct ntfs_inode *ni = ntfs_i(inode);
251 	const struct EA_INFO *info;
252 	struct EA_FULL *ea_all = NULL;
253 	const struct EA_FULL *ea;
254 	u32 off, len;
255 	int err;
256 
257 	if (!(ni->ni_flags & NI_FLAG_EA))
258 		return -ENODATA;
259 
260 	if (!required)
261 		ni_lock(ni);
262 
263 	len = 0;
264 
265 	if (name_len > 255) {
266 		err = -ENAMETOOLONG;
267 		goto out;
268 	}
269 
270 	err = ntfs_read_ea(ni, &ea_all, 0, &info);
271 	if (err)
272 		goto out;
273 
274 	if (!info)
275 		goto out;
276 
277 	/* Enumerate all xattrs. */
278 	if (!find_ea(ea_all, le32_to_cpu(info->size), name, name_len, &off,
279 		     NULL)) {
280 		err = -ENODATA;
281 		goto out;
282 	}
283 	ea = Add2Ptr(ea_all, off);
284 
285 	len = le16_to_cpu(ea->elength);
286 	if (!buffer) {
287 		err = 0;
288 		goto out;
289 	}
290 
291 	if (len > size) {
292 		err = -ERANGE;
293 		if (required)
294 			*required = len;
295 		goto out;
296 	}
297 
298 	memcpy(buffer, ea->name + ea->name_len + 1, len);
299 	err = 0;
300 
301 out:
302 	kfree(ea_all);
303 	if (!required)
304 		ni_unlock(ni);
305 
306 	return err ? err : len;
307 }
308 
309 static noinline int ntfs_set_ea(struct inode *inode, const char *name,
310 				size_t name_len, const void *value,
311 				size_t val_size, int flags, bool locked,
312 				__le16 *ea_size)
313 {
314 	struct ntfs_inode *ni = ntfs_i(inode);
315 	struct ntfs_sb_info *sbi = ni->mi.sbi;
316 	int err;
317 	struct EA_INFO ea_info;
318 	const struct EA_INFO *info;
319 	struct EA_FULL *new_ea;
320 	struct EA_FULL *ea_all = NULL;
321 	size_t add, new_pack;
322 	u32 off, size, ea_sz;
323 	__le16 size_pack;
324 	struct ATTRIB *attr;
325 	struct ATTR_LIST_ENTRY *le;
326 	struct mft_inode *mi;
327 	struct runs_tree ea_run;
328 	u64 new_sz;
329 	void *p;
330 
331 	if (!locked)
332 		ni_lock(ni);
333 
334 	run_init(&ea_run);
335 
336 	if (name_len > 255) {
337 		err = -ENAMETOOLONG;
338 		goto out;
339 	}
340 
341 	add = ALIGN(struct_size(ea_all, name, 1 + name_len + val_size), 4);
342 
343 	err = ntfs_read_ea(ni, &ea_all, add, &info);
344 	if (err)
345 		goto out;
346 
347 	if (!info) {
348 		memset(&ea_info, 0, sizeof(ea_info));
349 		size = 0;
350 		size_pack = 0;
351 	} else {
352 		memcpy(&ea_info, info, sizeof(ea_info));
353 		size = le32_to_cpu(ea_info.size);
354 		size_pack = ea_info.size_pack;
355 	}
356 
357 	if (info && find_ea(ea_all, size, name, name_len, &off, &ea_sz)) {
358 		struct EA_FULL *ea;
359 
360 		if (flags & XATTR_CREATE) {
361 			err = -EEXIST;
362 			goto out;
363 		}
364 
365 		ea = Add2Ptr(ea_all, off);
366 
367 		/*
368 		 * Check simple case when we try to insert xattr with the same value
369 		 * e.g. ntfs_save_wsl_perm
370 		 */
371 		if (val_size && le16_to_cpu(ea->elength) == val_size &&
372 		    !memcmp(ea->name + ea->name_len + 1, value, val_size)) {
373 			/* xattr already contains the required value. */
374 			goto out;
375 		}
376 
377 		/* Remove current xattr. */
378 		if (ea->flags & FILE_NEED_EA)
379 			le16_add_cpu(&ea_info.count, -1);
380 
381 		le16_add_cpu(&ea_info.size_pack, 0 - packed_ea_size(ea));
382 
383 		memmove(ea, Add2Ptr(ea, ea_sz), size - off - ea_sz);
384 
385 		size -= ea_sz;
386 		memset(Add2Ptr(ea_all, size), 0, ea_sz);
387 
388 		ea_info.size = cpu_to_le32(size);
389 
390 		if ((flags & XATTR_REPLACE) && !val_size) {
391 			/* Remove xattr. */
392 			goto update_ea;
393 		}
394 	} else {
395 		if (flags & XATTR_REPLACE) {
396 			err = -ENODATA;
397 			goto out;
398 		}
399 
400 		if (!ea_all) {
401 			ea_all = kzalloc(add, GFP_NOFS);
402 			if (!ea_all) {
403 				err = -ENOMEM;
404 				goto out;
405 			}
406 		}
407 	}
408 
409 	/* Append new xattr. */
410 	new_ea = Add2Ptr(ea_all, size);
411 	new_ea->size = cpu_to_le32(add);
412 	new_ea->flags = 0;
413 	new_ea->name_len = name_len;
414 	new_ea->elength = cpu_to_le16(val_size);
415 	memcpy(new_ea->name, name, name_len);
416 	new_ea->name[name_len] = 0;
417 	memcpy(new_ea->name + name_len + 1, value, val_size);
418 	new_pack = le16_to_cpu(ea_info.size_pack) + packed_ea_size(new_ea);
419 	ea_info.size_pack = cpu_to_le16(new_pack);
420 	/* New size of ATTR_EA. */
421 	size += add;
422 	ea_info.size = cpu_to_le32(size);
423 
424 	/*
425 	 * 1. Check ea_info.size_pack for overflow.
426 	 * 2. New attribute size must fit value from $AttrDef
427 	 */
428 	if (new_pack > 0xffff || size > sbi->ea_max_size) {
429 		ntfs_inode_warn(
430 			inode,
431 			"The size of extended attributes must not exceed 64KiB");
432 		err = -EFBIG; // -EINVAL?
433 		goto out;
434 	}
435 
436 update_ea:
437 
438 	if (!info) {
439 		/* Create xattr. */
440 		if (!size) {
441 			err = 0;
442 			goto out;
443 		}
444 
445 		err = ni_insert_resident(ni, sizeof(struct EA_INFO),
446 					 ATTR_EA_INFO, NULL, 0, NULL, NULL,
447 					 NULL);
448 		if (err)
449 			goto out;
450 
451 		err = ni_insert_resident(ni, 0, ATTR_EA, NULL, 0, NULL, NULL,
452 					 NULL);
453 		if (err)
454 			goto out;
455 	}
456 
457 	new_sz = size;
458 	err = attr_set_size(ni, ATTR_EA, NULL, 0, &ea_run, new_sz, &new_sz,
459 			    false, NULL);
460 	if (err)
461 		goto out;
462 
463 	le = NULL;
464 	attr = ni_find_attr(ni, NULL, &le, ATTR_EA_INFO, NULL, 0, NULL, &mi);
465 	if (!attr) {
466 		err = -EINVAL;
467 		goto out;
468 	}
469 
470 	if (!size) {
471 		/* Delete xattr, ATTR_EA_INFO */
472 		ni_remove_attr_le(ni, attr, mi, le);
473 	} else {
474 		p = resident_data_ex(attr, sizeof(struct EA_INFO));
475 		if (!p) {
476 			err = -EINVAL;
477 			goto out;
478 		}
479 		memcpy(p, &ea_info, sizeof(struct EA_INFO));
480 		mi->dirty = true;
481 	}
482 
483 	le = NULL;
484 	attr = ni_find_attr(ni, NULL, &le, ATTR_EA, NULL, 0, NULL, &mi);
485 	if (!attr) {
486 		err = -EINVAL;
487 		goto out;
488 	}
489 
490 	if (!size) {
491 		/* Delete xattr, ATTR_EA */
492 		ni_remove_attr_le(ni, attr, mi, le);
493 	} else if (attr->non_res) {
494 		err = attr_load_runs_range(ni, ATTR_EA, NULL, 0, &ea_run, 0,
495 					   size);
496 		if (err)
497 			goto out;
498 
499 		err = ntfs_sb_write_run(sbi, &ea_run, 0, ea_all, size, 0);
500 		if (err)
501 			goto out;
502 	} else {
503 		p = resident_data_ex(attr, size);
504 		if (!p) {
505 			err = -EINVAL;
506 			goto out;
507 		}
508 		memcpy(p, ea_all, size);
509 		mi->dirty = true;
510 	}
511 
512 	/* Check if we delete the last xattr. */
513 	if (size)
514 		ni->ni_flags |= NI_FLAG_EA;
515 	else
516 		ni->ni_flags &= ~NI_FLAG_EA;
517 
518 	if (ea_info.size_pack != size_pack)
519 		ni->ni_flags |= NI_FLAG_UPDATE_PARENT;
520 	if (ea_size)
521 		*ea_size = ea_info.size_pack;
522 	mark_inode_dirty(&ni->vfs_inode);
523 
524 out:
525 	if (!locked)
526 		ni_unlock(ni);
527 
528 	run_close(&ea_run);
529 	kfree(ea_all);
530 
531 	return err;
532 }
533 
534 #ifdef CONFIG_NTFS3_FS_POSIX_ACL
535 
536 /*
537  * ntfs_get_acl - inode_operations::get_acl
538  */
539 struct posix_acl *ntfs_get_acl(struct mnt_idmap *idmap, struct dentry *dentry,
540 			       int type)
541 {
542 	struct inode *inode = d_inode(dentry);
543 	struct ntfs_inode *ni = ntfs_i(inode);
544 	const char *name;
545 	size_t name_len;
546 	struct posix_acl *acl;
547 	size_t req;
548 	int err;
549 	void *buf;
550 
551 	/* Allocate PATH_MAX bytes. */
552 	buf = __getname();
553 	if (!buf)
554 		return ERR_PTR(-ENOMEM);
555 
556 	/* Possible values of 'type' was already checked above. */
557 	if (type == ACL_TYPE_ACCESS) {
558 		name = XATTR_NAME_POSIX_ACL_ACCESS;
559 		name_len = sizeof(XATTR_NAME_POSIX_ACL_ACCESS) - 1;
560 	} else {
561 		name = XATTR_NAME_POSIX_ACL_DEFAULT;
562 		name_len = sizeof(XATTR_NAME_POSIX_ACL_DEFAULT) - 1;
563 	}
564 
565 	ni_lock(ni);
566 
567 	err = ntfs_get_ea(inode, name, name_len, buf, PATH_MAX, &req);
568 
569 	ni_unlock(ni);
570 
571 	/* Translate extended attribute to acl. */
572 	if (err >= 0) {
573 		acl = posix_acl_from_xattr(&init_user_ns, buf, err);
574 	} else if (err == -ENODATA) {
575 		acl = NULL;
576 	} else {
577 		acl = ERR_PTR(err);
578 	}
579 
580 	if (!IS_ERR(acl))
581 		set_cached_acl(inode, type, acl);
582 
583 	__putname(buf);
584 
585 	return acl;
586 }
587 
588 static noinline int ntfs_set_acl_ex(struct mnt_idmap *idmap,
589 				    struct inode *inode, struct posix_acl *acl,
590 				    int type, bool init_acl)
591 {
592 	const char *name;
593 	size_t size, name_len;
594 	void *value;
595 	int err;
596 	int flags;
597 	umode_t mode;
598 
599 	if (S_ISLNK(inode->i_mode))
600 		return -EOPNOTSUPP;
601 
602 	mode = inode->i_mode;
603 	switch (type) {
604 	case ACL_TYPE_ACCESS:
605 		/* Do not change i_mode if we are in init_acl */
606 		if (acl && !init_acl) {
607 			err = posix_acl_update_mode(idmap, inode, &mode, &acl);
608 			if (err)
609 				return err;
610 		}
611 		name = XATTR_NAME_POSIX_ACL_ACCESS;
612 		name_len = sizeof(XATTR_NAME_POSIX_ACL_ACCESS) - 1;
613 		break;
614 
615 	case ACL_TYPE_DEFAULT:
616 		if (!S_ISDIR(inode->i_mode))
617 			return acl ? -EACCES : 0;
618 		name = XATTR_NAME_POSIX_ACL_DEFAULT;
619 		name_len = sizeof(XATTR_NAME_POSIX_ACL_DEFAULT) - 1;
620 		break;
621 
622 	default:
623 		return -EINVAL;
624 	}
625 
626 	if (!acl) {
627 		/* Remove xattr if it can be presented via mode. */
628 		size = 0;
629 		value = NULL;
630 		flags = XATTR_REPLACE;
631 	} else {
632 		size = posix_acl_xattr_size(acl->a_count);
633 		value = kmalloc(size, GFP_NOFS);
634 		if (!value)
635 			return -ENOMEM;
636 		err = posix_acl_to_xattr(&init_user_ns, acl, value, size);
637 		if (err < 0)
638 			goto out;
639 		flags = 0;
640 	}
641 
642 	err = ntfs_set_ea(inode, name, name_len, value, size, flags, 0, NULL);
643 	if (err == -ENODATA && !size)
644 		err = 0; /* Removing non existed xattr. */
645 	if (!err) {
646 		set_cached_acl(inode, type, acl);
647 		inode->i_mode = mode;
648 		inode_set_ctime_current(inode);
649 		mark_inode_dirty(inode);
650 	}
651 
652 out:
653 	kfree(value);
654 
655 	return err;
656 }
657 
658 /*
659  * ntfs_set_acl - inode_operations::set_acl
660  */
661 int ntfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
662 		 struct posix_acl *acl, int type)
663 {
664 	return ntfs_set_acl_ex(idmap, d_inode(dentry), acl, type, false);
665 }
666 
667 /*
668  * ntfs_init_acl - Initialize the ACLs of a new inode.
669  *
670  * Called from ntfs_create_inode().
671  */
672 int ntfs_init_acl(struct mnt_idmap *idmap, struct inode *inode,
673 		  struct inode *dir)
674 {
675 	struct posix_acl *default_acl, *acl;
676 	int err;
677 
678 	err = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
679 	if (err)
680 		return err;
681 
682 	if (default_acl) {
683 		err = ntfs_set_acl_ex(idmap, inode, default_acl,
684 				      ACL_TYPE_DEFAULT, true);
685 		posix_acl_release(default_acl);
686 	} else {
687 		inode->i_default_acl = NULL;
688 	}
689 
690 	if (acl) {
691 		if (!err)
692 			err = ntfs_set_acl_ex(idmap, inode, acl,
693 					      ACL_TYPE_ACCESS, true);
694 		posix_acl_release(acl);
695 	} else {
696 		inode->i_acl = NULL;
697 	}
698 
699 	return err;
700 }
701 #endif
702 
703 /*
704  * ntfs_acl_chmod - Helper for ntfs3_setattr().
705  */
706 int ntfs_acl_chmod(struct mnt_idmap *idmap, struct dentry *dentry)
707 {
708 	struct inode *inode = d_inode(dentry);
709 	struct super_block *sb = inode->i_sb;
710 
711 	if (!(sb->s_flags & SB_POSIXACL))
712 		return 0;
713 
714 	if (S_ISLNK(inode->i_mode))
715 		return -EOPNOTSUPP;
716 
717 	return posix_acl_chmod(idmap, dentry, inode->i_mode);
718 }
719 
720 /*
721  * ntfs_listxattr - inode_operations::listxattr
722  */
723 ssize_t ntfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
724 {
725 	struct inode *inode = d_inode(dentry);
726 	struct ntfs_inode *ni = ntfs_i(inode);
727 	ssize_t ret;
728 
729 	if (!(ni->ni_flags & NI_FLAG_EA)) {
730 		/* no xattr in file */
731 		return 0;
732 	}
733 
734 	ni_lock(ni);
735 
736 	ret = ntfs_list_ea(ni, buffer, size);
737 
738 	ni_unlock(ni);
739 
740 	return ret;
741 }
742 
743 static int ntfs_getxattr(const struct xattr_handler *handler, struct dentry *de,
744 			 struct inode *inode, const char *name, void *buffer,
745 			 size_t size)
746 {
747 	int err;
748 	struct ntfs_inode *ni = ntfs_i(inode);
749 
750 	if (unlikely(ntfs3_forced_shutdown(inode->i_sb)))
751 		return -EIO;
752 
753 	/* Dispatch request. */
754 	if (!strcmp(name, SYSTEM_DOS_ATTRIB)) {
755 		/* system.dos_attrib */
756 		if (!buffer) {
757 			err = sizeof(u8);
758 		} else if (size < sizeof(u8)) {
759 			err = -ENODATA;
760 		} else {
761 			err = sizeof(u8);
762 			*(u8 *)buffer = le32_to_cpu(ni->std_fa);
763 		}
764 		goto out;
765 	}
766 
767 	if (!strcmp(name, SYSTEM_NTFS_ATTRIB) ||
768 	    !strcmp(name, SYSTEM_NTFS_ATTRIB_BE)) {
769 		/* system.ntfs_attrib */
770 		if (!buffer) {
771 			err = sizeof(u32);
772 		} else if (size < sizeof(u32)) {
773 			err = -ENODATA;
774 		} else {
775 			err = sizeof(u32);
776 			*(u32 *)buffer = le32_to_cpu(ni->std_fa);
777 			if (!strcmp(name, SYSTEM_NTFS_ATTRIB_BE))
778 				*(__be32 *)buffer = cpu_to_be32(*(u32 *)buffer);
779 		}
780 		goto out;
781 	}
782 
783 	if (!strcmp(name, SYSTEM_NTFS_SECURITY)) {
784 		/* system.ntfs_security*/
785 		struct SECURITY_DESCRIPTOR_RELATIVE *sd = NULL;
786 		size_t sd_size = 0;
787 
788 		if (!is_ntfs3(ni->mi.sbi)) {
789 			/* We should get nt4 security. */
790 			err = -EINVAL;
791 			goto out;
792 		} else if (le32_to_cpu(ni->std_security_id) <
793 			   SECURITY_ID_FIRST) {
794 			err = -ENOENT;
795 			goto out;
796 		}
797 
798 		err = ntfs_get_security_by_id(ni->mi.sbi, ni->std_security_id,
799 					      &sd, &sd_size);
800 		if (err)
801 			goto out;
802 
803 		if (!is_sd_valid(sd, sd_size)) {
804 			ntfs_inode_warn(
805 				inode,
806 				"looks like you get incorrect security descriptor id=%u",
807 				ni->std_security_id);
808 		}
809 
810 		if (!buffer) {
811 			err = sd_size;
812 		} else if (size < sd_size) {
813 			err = -ENODATA;
814 		} else {
815 			err = sd_size;
816 			memcpy(buffer, sd, sd_size);
817 		}
818 		kfree(sd);
819 		goto out;
820 	}
821 
822 	/* Deal with NTFS extended attribute. */
823 	err = ntfs_get_ea(inode, name, strlen(name), buffer, size, NULL);
824 
825 out:
826 	return err;
827 }
828 
829 /*
830  * ntfs_setxattr - inode_operations::setxattr
831  */
832 static noinline int ntfs_setxattr(const struct xattr_handler *handler,
833 				  struct mnt_idmap *idmap, struct dentry *de,
834 				  struct inode *inode, const char *name,
835 				  const void *value, size_t size, int flags)
836 {
837 	int err = -EINVAL;
838 	struct ntfs_inode *ni = ntfs_i(inode);
839 	enum FILE_ATTRIBUTE new_fa;
840 
841 	/* Dispatch request. */
842 	if (!strcmp(name, SYSTEM_DOS_ATTRIB)) {
843 		if (sizeof(u8) != size)
844 			goto out;
845 		new_fa = cpu_to_le32(*(u8 *)value);
846 		goto set_new_fa;
847 	}
848 
849 	if (!strcmp(name, SYSTEM_NTFS_ATTRIB) ||
850 	    !strcmp(name, SYSTEM_NTFS_ATTRIB_BE)) {
851 		if (size != sizeof(u32))
852 			goto out;
853 		if (!strcmp(name, SYSTEM_NTFS_ATTRIB_BE))
854 			new_fa = cpu_to_le32(be32_to_cpu(*(__be32 *)value));
855 		else
856 			new_fa = cpu_to_le32(*(u32 *)value);
857 
858 		if (S_ISREG(inode->i_mode)) {
859 			/* Process compressed/sparsed in special way. */
860 			ni_lock(ni);
861 			err = ni_new_attr_flags(ni, new_fa);
862 			ni_unlock(ni);
863 			if (err)
864 				goto out;
865 		}
866 set_new_fa:
867 		/*
868 		 * Thanks Mark Harmstone:
869 		 * Keep directory bit consistency.
870 		 */
871 		if (S_ISDIR(inode->i_mode))
872 			new_fa |= FILE_ATTRIBUTE_DIRECTORY;
873 		else
874 			new_fa &= ~FILE_ATTRIBUTE_DIRECTORY;
875 
876 		if (ni->std_fa != new_fa) {
877 			ni->std_fa = new_fa;
878 			if (new_fa & FILE_ATTRIBUTE_READONLY)
879 				inode->i_mode &= ~0222;
880 			else
881 				inode->i_mode |= 0222;
882 			/* Std attribute always in primary record. */
883 			ni->mi.dirty = true;
884 			mark_inode_dirty(inode);
885 		}
886 		err = 0;
887 
888 		goto out;
889 	}
890 
891 	if (!strcmp(name, SYSTEM_NTFS_SECURITY)) {
892 		/* system.ntfs_security*/
893 		__le32 security_id;
894 		bool inserted;
895 		struct ATTR_STD_INFO5 *std;
896 
897 		if (!is_ntfs3(ni->mi.sbi)) {
898 			/*
899 			 * We should replace ATTR_SECURE.
900 			 * Skip this way cause it is nt4 feature.
901 			 */
902 			err = -EINVAL;
903 			goto out;
904 		}
905 
906 		if (!is_sd_valid(value, size)) {
907 			err = -EINVAL;
908 			ntfs_inode_warn(
909 				inode,
910 				"you try to set invalid security descriptor");
911 			goto out;
912 		}
913 
914 		err = ntfs_insert_security(ni->mi.sbi, value, size,
915 					   &security_id, &inserted);
916 		if (err)
917 			goto out;
918 
919 		ni_lock(ni);
920 		std = ni_std5(ni);
921 		if (!std) {
922 			err = -EINVAL;
923 		} else if (std->security_id != security_id) {
924 			std->security_id = ni->std_security_id = security_id;
925 			/* Std attribute always in primary record. */
926 			ni->mi.dirty = true;
927 			mark_inode_dirty(&ni->vfs_inode);
928 		}
929 		ni_unlock(ni);
930 		goto out;
931 	}
932 
933 	/* Deal with NTFS extended attribute. */
934 	err = ntfs_set_ea(inode, name, strlen(name), value, size, flags, 0,
935 			  NULL);
936 
937 out:
938 	inode_set_ctime_current(inode);
939 	mark_inode_dirty(inode);
940 
941 	return err;
942 }
943 
944 /*
945  * ntfs_save_wsl_perm
946  *
947  * save uid/gid/mode in xattr
948  */
949 int ntfs_save_wsl_perm(struct inode *inode, __le16 *ea_size)
950 {
951 	int err;
952 	__le32 value;
953 	struct ntfs_inode *ni = ntfs_i(inode);
954 
955 	ni_lock(ni);
956 	value = cpu_to_le32(i_uid_read(inode));
957 	err = ntfs_set_ea(inode, "$LXUID", sizeof("$LXUID") - 1, &value,
958 			  sizeof(value), 0, true, ea_size);
959 	if (err)
960 		goto out;
961 
962 	value = cpu_to_le32(i_gid_read(inode));
963 	err = ntfs_set_ea(inode, "$LXGID", sizeof("$LXGID") - 1, &value,
964 			  sizeof(value), 0, true, ea_size);
965 	if (err)
966 		goto out;
967 
968 	value = cpu_to_le32(inode->i_mode);
969 	err = ntfs_set_ea(inode, "$LXMOD", sizeof("$LXMOD") - 1, &value,
970 			  sizeof(value), 0, true, ea_size);
971 	if (err)
972 		goto out;
973 
974 	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
975 		value = cpu_to_le32(inode->i_rdev);
976 		err = ntfs_set_ea(inode, "$LXDEV", sizeof("$LXDEV") - 1, &value,
977 				  sizeof(value), 0, true, ea_size);
978 		if (err)
979 			goto out;
980 	}
981 
982 out:
983 	ni_unlock(ni);
984 	/* In case of error should we delete all WSL xattr? */
985 	return err;
986 }
987 
988 /*
989  * ntfs_get_wsl_perm
990  *
991  * get uid/gid/mode from xattr
992  * it is called from ntfs_iget5->ntfs_read_mft
993  */
994 void ntfs_get_wsl_perm(struct inode *inode)
995 {
996 	size_t sz;
997 	__le32 value[3];
998 
999 	if (ntfs_get_ea(inode, "$LXUID", sizeof("$LXUID") - 1, &value[0],
1000 			sizeof(value[0]), &sz) == sizeof(value[0]) &&
1001 	    ntfs_get_ea(inode, "$LXGID", sizeof("$LXGID") - 1, &value[1],
1002 			sizeof(value[1]), &sz) == sizeof(value[1]) &&
1003 	    ntfs_get_ea(inode, "$LXMOD", sizeof("$LXMOD") - 1, &value[2],
1004 			sizeof(value[2]), &sz) == sizeof(value[2])) {
1005 		i_uid_write(inode, (uid_t)le32_to_cpu(value[0]));
1006 		i_gid_write(inode, (gid_t)le32_to_cpu(value[1]));
1007 		inode->i_mode = le32_to_cpu(value[2]);
1008 
1009 		if (ntfs_get_ea(inode, "$LXDEV", sizeof("$$LXDEV") - 1,
1010 				&value[0], sizeof(value),
1011 				&sz) == sizeof(value[0])) {
1012 			inode->i_rdev = le32_to_cpu(value[0]);
1013 		}
1014 	}
1015 }
1016 
1017 static bool ntfs_xattr_user_list(struct dentry *dentry)
1018 {
1019 	return true;
1020 }
1021 
1022 // clang-format off
1023 static const struct xattr_handler ntfs_other_xattr_handler = {
1024 	.prefix	= "",
1025 	.get	= ntfs_getxattr,
1026 	.set	= ntfs_setxattr,
1027 	.list	= ntfs_xattr_user_list,
1028 };
1029 
1030 const struct xattr_handler * const ntfs_xattr_handlers[] = {
1031 	&ntfs_other_xattr_handler,
1032 	NULL,
1033 };
1034 // clang-format on
1035