xref: /openbmc/linux/fs/f2fs/xattr.c (revision c0e297dc) 
1 /*
2  * fs/f2fs/xattr.c
3  *
4  * Copyright (c) 2012 Samsung Electronics Co., Ltd.
5  *             http://www.samsung.com/
6  *
7  * Portions of this code from linux/fs/ext2/xattr.c
8  *
9  * Copyright (C) 2001-2003 Andreas Gruenbacher <agruen@suse.de>
10  *
11  * Fix by Harrison Xing <harrison@mountainviewdata.com>.
12  * Extended attributes for symlinks and special files added per
13  *  suggestion of Luka Renko <luka.renko@hermes.si>.
14  * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
15  *  Red Hat Inc.
16  *
17  * This program is free software; you can redistribute it and/or modify
18  * it under the terms of the GNU General Public License version 2 as
19  * published by the Free Software Foundation.
20  */
21 #include <linux/rwsem.h>
22 #include <linux/f2fs_fs.h>
23 #include <linux/security.h>
24 #include <linux/posix_acl_xattr.h>
25 #include "f2fs.h"
26 #include "xattr.h"
27 
28 static size_t f2fs_xattr_generic_list(struct dentry *dentry, char *list,
29 		size_t list_size, const char *name, size_t len, int type)
30 {
31 	struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
32 	int total_len, prefix_len = 0;
33 	const char *prefix = NULL;
34 
35 	switch (type) {
36 	case F2FS_XATTR_INDEX_USER:
37 		if (!test_opt(sbi, XATTR_USER))
38 			return -EOPNOTSUPP;
39 		prefix = XATTR_USER_PREFIX;
40 		prefix_len = XATTR_USER_PREFIX_LEN;
41 		break;
42 	case F2FS_XATTR_INDEX_TRUSTED:
43 		if (!capable(CAP_SYS_ADMIN))
44 			return -EPERM;
45 		prefix = XATTR_TRUSTED_PREFIX;
46 		prefix_len = XATTR_TRUSTED_PREFIX_LEN;
47 		break;
48 	case F2FS_XATTR_INDEX_SECURITY:
49 		prefix = XATTR_SECURITY_PREFIX;
50 		prefix_len = XATTR_SECURITY_PREFIX_LEN;
51 		break;
52 	default:
53 		return -EINVAL;
54 	}
55 
56 	total_len = prefix_len + len + 1;
57 	if (list && total_len <= list_size) {
58 		memcpy(list, prefix, prefix_len);
59 		memcpy(list + prefix_len, name, len);
60 		list[prefix_len + len] = '\0';
61 	}
62 	return total_len;
63 }
64 
65 static int f2fs_xattr_generic_get(struct dentry *dentry, const char *name,
66 		void *buffer, size_t size, int type)
67 {
68 	struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
69 
70 	switch (type) {
71 	case F2FS_XATTR_INDEX_USER:
72 		if (!test_opt(sbi, XATTR_USER))
73 			return -EOPNOTSUPP;
74 		break;
75 	case F2FS_XATTR_INDEX_TRUSTED:
76 		if (!capable(CAP_SYS_ADMIN))
77 			return -EPERM;
78 		break;
79 	case F2FS_XATTR_INDEX_SECURITY:
80 		break;
81 	default:
82 		return -EINVAL;
83 	}
84 	if (strcmp(name, "") == 0)
85 		return -EINVAL;
86 	return f2fs_getxattr(d_inode(dentry), type, name, buffer, size, NULL);
87 }
88 
89 static int f2fs_xattr_generic_set(struct dentry *dentry, const char *name,
90 		const void *value, size_t size, int flags, int type)
91 {
92 	struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
93 
94 	switch (type) {
95 	case F2FS_XATTR_INDEX_USER:
96 		if (!test_opt(sbi, XATTR_USER))
97 			return -EOPNOTSUPP;
98 		break;
99 	case F2FS_XATTR_INDEX_TRUSTED:
100 		if (!capable(CAP_SYS_ADMIN))
101 			return -EPERM;
102 		break;
103 	case F2FS_XATTR_INDEX_SECURITY:
104 		break;
105 	default:
106 		return -EINVAL;
107 	}
108 	if (strcmp(name, "") == 0)
109 		return -EINVAL;
110 
111 	return f2fs_setxattr(d_inode(dentry), type, name,
112 					value, size, NULL, flags);
113 }
114 
115 static size_t f2fs_xattr_advise_list(struct dentry *dentry, char *list,
116 		size_t list_size, const char *name, size_t len, int type)
117 {
118 	const char *xname = F2FS_SYSTEM_ADVISE_PREFIX;
119 	size_t size;
120 
121 	if (type != F2FS_XATTR_INDEX_ADVISE)
122 		return 0;
123 
124 	size = strlen(xname) + 1;
125 	if (list && size <= list_size)
126 		memcpy(list, xname, size);
127 	return size;
128 }
129 
130 static int f2fs_xattr_advise_get(struct dentry *dentry, const char *name,
131 		void *buffer, size_t size, int type)
132 {
133 	struct inode *inode = d_inode(dentry);
134 
135 	if (strcmp(name, "") != 0)
136 		return -EINVAL;
137 
138 	if (buffer)
139 		*((char *)buffer) = F2FS_I(inode)->i_advise;
140 	return sizeof(char);
141 }
142 
143 static int f2fs_xattr_advise_set(struct dentry *dentry, const char *name,
144 		const void *value, size_t size, int flags, int type)
145 {
146 	struct inode *inode = d_inode(dentry);
147 
148 	if (strcmp(name, "") != 0)
149 		return -EINVAL;
150 	if (!inode_owner_or_capable(inode))
151 		return -EPERM;
152 	if (value == NULL)
153 		return -EINVAL;
154 
155 	F2FS_I(inode)->i_advise |= *(char *)value;
156 	mark_inode_dirty(inode);
157 	return 0;
158 }
159 
160 #ifdef CONFIG_F2FS_FS_SECURITY
161 static int f2fs_initxattrs(struct inode *inode, const struct xattr *xattr_array,
162 		void *page)
163 {
164 	const struct xattr *xattr;
165 	int err = 0;
166 
167 	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
168 		err = f2fs_setxattr(inode, F2FS_XATTR_INDEX_SECURITY,
169 				xattr->name, xattr->value,
170 				xattr->value_len, (struct page *)page, 0);
171 		if (err < 0)
172 			break;
173 	}
174 	return err;
175 }
176 
177 int f2fs_init_security(struct inode *inode, struct inode *dir,
178 				const struct qstr *qstr, struct page *ipage)
179 {
180 	return security_inode_init_security(inode, dir, qstr,
181 				&f2fs_initxattrs, ipage);
182 }
183 #endif
184 
185 const struct xattr_handler f2fs_xattr_user_handler = {
186 	.prefix	= XATTR_USER_PREFIX,
187 	.flags	= F2FS_XATTR_INDEX_USER,
188 	.list	= f2fs_xattr_generic_list,
189 	.get	= f2fs_xattr_generic_get,
190 	.set	= f2fs_xattr_generic_set,
191 };
192 
193 const struct xattr_handler f2fs_xattr_trusted_handler = {
194 	.prefix	= XATTR_TRUSTED_PREFIX,
195 	.flags	= F2FS_XATTR_INDEX_TRUSTED,
196 	.list	= f2fs_xattr_generic_list,
197 	.get	= f2fs_xattr_generic_get,
198 	.set	= f2fs_xattr_generic_set,
199 };
200 
201 const struct xattr_handler f2fs_xattr_advise_handler = {
202 	.prefix = F2FS_SYSTEM_ADVISE_PREFIX,
203 	.flags	= F2FS_XATTR_INDEX_ADVISE,
204 	.list   = f2fs_xattr_advise_list,
205 	.get    = f2fs_xattr_advise_get,
206 	.set    = f2fs_xattr_advise_set,
207 };
208 
209 const struct xattr_handler f2fs_xattr_security_handler = {
210 	.prefix	= XATTR_SECURITY_PREFIX,
211 	.flags	= F2FS_XATTR_INDEX_SECURITY,
212 	.list	= f2fs_xattr_generic_list,
213 	.get	= f2fs_xattr_generic_get,
214 	.set	= f2fs_xattr_generic_set,
215 };
216 
217 static const struct xattr_handler *f2fs_xattr_handler_map[] = {
218 	[F2FS_XATTR_INDEX_USER] = &f2fs_xattr_user_handler,
219 #ifdef CONFIG_F2FS_FS_POSIX_ACL
220 	[F2FS_XATTR_INDEX_POSIX_ACL_ACCESS] = &posix_acl_access_xattr_handler,
221 	[F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
222 #endif
223 	[F2FS_XATTR_INDEX_TRUSTED] = &f2fs_xattr_trusted_handler,
224 #ifdef CONFIG_F2FS_FS_SECURITY
225 	[F2FS_XATTR_INDEX_SECURITY] = &f2fs_xattr_security_handler,
226 #endif
227 	[F2FS_XATTR_INDEX_ADVISE] = &f2fs_xattr_advise_handler,
228 };
229 
230 const struct xattr_handler *f2fs_xattr_handlers[] = {
231 	&f2fs_xattr_user_handler,
232 #ifdef CONFIG_F2FS_FS_POSIX_ACL
233 	&posix_acl_access_xattr_handler,
234 	&posix_acl_default_xattr_handler,
235 #endif
236 	&f2fs_xattr_trusted_handler,
237 #ifdef CONFIG_F2FS_FS_SECURITY
238 	&f2fs_xattr_security_handler,
239 #endif
240 	&f2fs_xattr_advise_handler,
241 	NULL,
242 };
243 
244 static inline const struct xattr_handler *f2fs_xattr_handler(int index)
245 {
246 	const struct xattr_handler *handler = NULL;
247 
248 	if (index > 0 && index < ARRAY_SIZE(f2fs_xattr_handler_map))
249 		handler = f2fs_xattr_handler_map[index];
250 	return handler;
251 }
252 
253 static struct f2fs_xattr_entry *__find_xattr(void *base_addr, int index,
254 					size_t len, const char *name)
255 {
256 	struct f2fs_xattr_entry *entry;
257 
258 	list_for_each_xattr(entry, base_addr) {
259 		if (entry->e_name_index != index)
260 			continue;
261 		if (entry->e_name_len != len)
262 			continue;
263 		if (!memcmp(entry->e_name, name, len))
264 			break;
265 	}
266 	return entry;
267 }
268 
269 static void *read_all_xattrs(struct inode *inode, struct page *ipage)
270 {
271 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
272 	struct f2fs_xattr_header *header;
273 	size_t size = PAGE_SIZE, inline_size = 0;
274 	void *txattr_addr;
275 
276 	inline_size = inline_xattr_size(inode);
277 
278 	txattr_addr = kzalloc(inline_size + size, GFP_F2FS_ZERO);
279 	if (!txattr_addr)
280 		return NULL;
281 
282 	/* read from inline xattr */
283 	if (inline_size) {
284 		struct page *page = NULL;
285 		void *inline_addr;
286 
287 		if (ipage) {
288 			inline_addr = inline_xattr_addr(ipage);
289 		} else {
290 			page = get_node_page(sbi, inode->i_ino);
291 			if (IS_ERR(page))
292 				goto fail;
293 			inline_addr = inline_xattr_addr(page);
294 		}
295 		memcpy(txattr_addr, inline_addr, inline_size);
296 		f2fs_put_page(page, 1);
297 	}
298 
299 	/* read from xattr node block */
300 	if (F2FS_I(inode)->i_xattr_nid) {
301 		struct page *xpage;
302 		void *xattr_addr;
303 
304 		/* The inode already has an extended attribute block. */
305 		xpage = get_node_page(sbi, F2FS_I(inode)->i_xattr_nid);
306 		if (IS_ERR(xpage))
307 			goto fail;
308 
309 		xattr_addr = page_address(xpage);
310 		memcpy(txattr_addr + inline_size, xattr_addr, PAGE_SIZE);
311 		f2fs_put_page(xpage, 1);
312 	}
313 
314 	header = XATTR_HDR(txattr_addr);
315 
316 	/* never been allocated xattrs */
317 	if (le32_to_cpu(header->h_magic) != F2FS_XATTR_MAGIC) {
318 		header->h_magic = cpu_to_le32(F2FS_XATTR_MAGIC);
319 		header->h_refcount = cpu_to_le32(1);
320 	}
321 	return txattr_addr;
322 fail:
323 	kzfree(txattr_addr);
324 	return NULL;
325 }
326 
327 static inline int write_all_xattrs(struct inode *inode, __u32 hsize,
328 				void *txattr_addr, struct page *ipage)
329 {
330 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
331 	size_t inline_size = 0;
332 	void *xattr_addr;
333 	struct page *xpage;
334 	nid_t new_nid = 0;
335 	int err;
336 
337 	inline_size = inline_xattr_size(inode);
338 
339 	if (hsize > inline_size && !F2FS_I(inode)->i_xattr_nid)
340 		if (!alloc_nid(sbi, &new_nid))
341 			return -ENOSPC;
342 
343 	/* write to inline xattr */
344 	if (inline_size) {
345 		struct page *page = NULL;
346 		void *inline_addr;
347 
348 		if (ipage) {
349 			inline_addr = inline_xattr_addr(ipage);
350 			f2fs_wait_on_page_writeback(ipage, NODE);
351 		} else {
352 			page = get_node_page(sbi, inode->i_ino);
353 			if (IS_ERR(page)) {
354 				alloc_nid_failed(sbi, new_nid);
355 				return PTR_ERR(page);
356 			}
357 			inline_addr = inline_xattr_addr(page);
358 			f2fs_wait_on_page_writeback(page, NODE);
359 		}
360 		memcpy(inline_addr, txattr_addr, inline_size);
361 		f2fs_put_page(page, 1);
362 
363 		/* no need to use xattr node block */
364 		if (hsize <= inline_size) {
365 			err = truncate_xattr_node(inode, ipage);
366 			alloc_nid_failed(sbi, new_nid);
367 			return err;
368 		}
369 	}
370 
371 	/* write to xattr node block */
372 	if (F2FS_I(inode)->i_xattr_nid) {
373 		xpage = get_node_page(sbi, F2FS_I(inode)->i_xattr_nid);
374 		if (IS_ERR(xpage)) {
375 			alloc_nid_failed(sbi, new_nid);
376 			return PTR_ERR(xpage);
377 		}
378 		f2fs_bug_on(sbi, new_nid);
379 		f2fs_wait_on_page_writeback(xpage, NODE);
380 	} else {
381 		struct dnode_of_data dn;
382 		set_new_dnode(&dn, inode, NULL, NULL, new_nid);
383 		xpage = new_node_page(&dn, XATTR_NODE_OFFSET, ipage);
384 		if (IS_ERR(xpage)) {
385 			alloc_nid_failed(sbi, new_nid);
386 			return PTR_ERR(xpage);
387 		}
388 		alloc_nid_done(sbi, new_nid);
389 	}
390 
391 	xattr_addr = page_address(xpage);
392 	memcpy(xattr_addr, txattr_addr + inline_size, PAGE_SIZE -
393 						sizeof(struct node_footer));
394 	set_page_dirty(xpage);
395 	f2fs_put_page(xpage, 1);
396 
397 	/* need to checkpoint during fsync */
398 	F2FS_I(inode)->xattr_ver = cur_cp_version(F2FS_CKPT(sbi));
399 	return 0;
400 }
401 
402 int f2fs_getxattr(struct inode *inode, int index, const char *name,
403 		void *buffer, size_t buffer_size, struct page *ipage)
404 {
405 	struct f2fs_xattr_entry *entry;
406 	void *base_addr;
407 	int error = 0;
408 	size_t size, len;
409 
410 	if (name == NULL)
411 		return -EINVAL;
412 
413 	len = strlen(name);
414 	if (len > F2FS_NAME_LEN)
415 		return -ERANGE;
416 
417 	base_addr = read_all_xattrs(inode, ipage);
418 	if (!base_addr)
419 		return -ENOMEM;
420 
421 	entry = __find_xattr(base_addr, index, len, name);
422 	if (IS_XATTR_LAST_ENTRY(entry)) {
423 		error = -ENODATA;
424 		goto cleanup;
425 	}
426 
427 	size = le16_to_cpu(entry->e_value_size);
428 
429 	if (buffer && size > buffer_size) {
430 		error = -ERANGE;
431 		goto cleanup;
432 	}
433 
434 	if (buffer) {
435 		char *pval = entry->e_name + entry->e_name_len;
436 		memcpy(buffer, pval, size);
437 	}
438 	error = size;
439 
440 cleanup:
441 	kzfree(base_addr);
442 	return error;
443 }
444 
445 ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
446 {
447 	struct inode *inode = d_inode(dentry);
448 	struct f2fs_xattr_entry *entry;
449 	void *base_addr;
450 	int error = 0;
451 	size_t rest = buffer_size;
452 
453 	base_addr = read_all_xattrs(inode, NULL);
454 	if (!base_addr)
455 		return -ENOMEM;
456 
457 	list_for_each_xattr(entry, base_addr) {
458 		const struct xattr_handler *handler =
459 			f2fs_xattr_handler(entry->e_name_index);
460 		size_t size;
461 
462 		if (!handler)
463 			continue;
464 
465 		size = handler->list(dentry, buffer, rest, entry->e_name,
466 				entry->e_name_len, handler->flags);
467 		if (buffer && size > rest) {
468 			error = -ERANGE;
469 			goto cleanup;
470 		}
471 
472 		if (buffer)
473 			buffer += size;
474 		rest -= size;
475 	}
476 	error = buffer_size - rest;
477 cleanup:
478 	kzfree(base_addr);
479 	return error;
480 }
481 
482 static int __f2fs_setxattr(struct inode *inode, int index,
483 			const char *name, const void *value, size_t size,
484 			struct page *ipage, int flags)
485 {
486 	struct f2fs_inode_info *fi = F2FS_I(inode);
487 	struct f2fs_xattr_entry *here, *last;
488 	void *base_addr;
489 	int found, newsize;
490 	size_t len;
491 	__u32 new_hsize;
492 	int error = -ENOMEM;
493 
494 	if (name == NULL)
495 		return -EINVAL;
496 
497 	if (value == NULL)
498 		size = 0;
499 
500 	len = strlen(name);
501 
502 	if (len > F2FS_NAME_LEN || size > MAX_VALUE_LEN(inode))
503 		return -ERANGE;
504 
505 	base_addr = read_all_xattrs(inode, ipage);
506 	if (!base_addr)
507 		goto exit;
508 
509 	/* find entry with wanted name. */
510 	here = __find_xattr(base_addr, index, len, name);
511 
512 	found = IS_XATTR_LAST_ENTRY(here) ? 0 : 1;
513 
514 	if ((flags & XATTR_REPLACE) && !found) {
515 		error = -ENODATA;
516 		goto exit;
517 	} else if ((flags & XATTR_CREATE) && found) {
518 		error = -EEXIST;
519 		goto exit;
520 	}
521 
522 	last = here;
523 	while (!IS_XATTR_LAST_ENTRY(last))
524 		last = XATTR_NEXT_ENTRY(last);
525 
526 	newsize = XATTR_ALIGN(sizeof(struct f2fs_xattr_entry) + len + size);
527 
528 	/* 1. Check space */
529 	if (value) {
530 		int free;
531 		/*
532 		 * If value is NULL, it is remove operation.
533 		 * In case of update operation, we calculate free.
534 		 */
535 		free = MIN_OFFSET(inode) - ((char *)last - (char *)base_addr);
536 		if (found)
537 			free = free + ENTRY_SIZE(here);
538 
539 		if (unlikely(free < newsize)) {
540 			error = -ENOSPC;
541 			goto exit;
542 		}
543 	}
544 
545 	/* 2. Remove old entry */
546 	if (found) {
547 		/*
548 		 * If entry is found, remove old entry.
549 		 * If not found, remove operation is not needed.
550 		 */
551 		struct f2fs_xattr_entry *next = XATTR_NEXT_ENTRY(here);
552 		int oldsize = ENTRY_SIZE(here);
553 
554 		memmove(here, next, (char *)last - (char *)next);
555 		last = (struct f2fs_xattr_entry *)((char *)last - oldsize);
556 		memset(last, 0, oldsize);
557 	}
558 
559 	new_hsize = (char *)last - (char *)base_addr;
560 
561 	/* 3. Write new entry */
562 	if (value) {
563 		char *pval;
564 		/*
565 		 * Before we come here, old entry is removed.
566 		 * We just write new entry.
567 		 */
568 		memset(last, 0, newsize);
569 		last->e_name_index = index;
570 		last->e_name_len = len;
571 		memcpy(last->e_name, name, len);
572 		pval = last->e_name + len;
573 		memcpy(pval, value, size);
574 		last->e_value_size = cpu_to_le16(size);
575 		new_hsize += newsize;
576 	}
577 
578 	error = write_all_xattrs(inode, new_hsize, base_addr, ipage);
579 	if (error)
580 		goto exit;
581 
582 	if (is_inode_flag_set(fi, FI_ACL_MODE)) {
583 		inode->i_mode = fi->i_acl_mode;
584 		inode->i_ctime = CURRENT_TIME;
585 		clear_inode_flag(fi, FI_ACL_MODE);
586 	}
587 	if (index == F2FS_XATTR_INDEX_ENCRYPTION &&
588 			!strcmp(name, F2FS_XATTR_NAME_ENCRYPTION_CONTEXT))
589 		f2fs_set_encrypted_inode(inode);
590 
591 	if (ipage)
592 		update_inode(inode, ipage);
593 	else
594 		update_inode_page(inode);
595 exit:
596 	kzfree(base_addr);
597 	return error;
598 }
599 
600 int f2fs_setxattr(struct inode *inode, int index, const char *name,
601 				const void *value, size_t size,
602 				struct page *ipage, int flags)
603 {
604 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
605 	int err;
606 
607 	/* this case is only from init_inode_metadata */
608 	if (ipage)
609 		return __f2fs_setxattr(inode, index, name, value,
610 						size, ipage, flags);
611 	f2fs_balance_fs(sbi);
612 
613 	f2fs_lock_op(sbi);
614 	/* protect xattr_ver */
615 	down_write(&F2FS_I(inode)->i_sem);
616 	err = __f2fs_setxattr(inode, index, name, value, size, ipage, flags);
617 	up_write(&F2FS_I(inode)->i_sem);
618 	f2fs_unlock_op(sbi);
619 
620 	return err;
621 }
622