xref: /openbmc/linux/fs/f2fs/xattr.c (revision 93d90ad7) 
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(dentry->d_inode, 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(dentry->d_inode, 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 = dentry->d_inode;
134 
135 	if (strcmp(name, "") != 0)
136 		return -EINVAL;
137 
138 	*((char *)buffer) = F2FS_I(inode)->i_advise;
139 	return sizeof(char);
140 }
141 
142 static int f2fs_xattr_advise_set(struct dentry *dentry, const char *name,
143 		const void *value, size_t size, int flags, int type)
144 {
145 	struct inode *inode = dentry->d_inode;
146 
147 	if (strcmp(name, "") != 0)
148 		return -EINVAL;
149 	if (!inode_owner_or_capable(inode))
150 		return -EPERM;
151 	if (value == NULL)
152 		return -EINVAL;
153 
154 	F2FS_I(inode)->i_advise |= *(char *)value;
155 	return 0;
156 }
157 
158 #ifdef CONFIG_F2FS_FS_SECURITY
159 static int f2fs_initxattrs(struct inode *inode, const struct xattr *xattr_array,
160 		void *page)
161 {
162 	const struct xattr *xattr;
163 	int err = 0;
164 
165 	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
166 		err = f2fs_setxattr(inode, F2FS_XATTR_INDEX_SECURITY,
167 				xattr->name, xattr->value,
168 				xattr->value_len, (struct page *)page, 0);
169 		if (err < 0)
170 			break;
171 	}
172 	return err;
173 }
174 
175 int f2fs_init_security(struct inode *inode, struct inode *dir,
176 				const struct qstr *qstr, struct page *ipage)
177 {
178 	return security_inode_init_security(inode, dir, qstr,
179 				&f2fs_initxattrs, ipage);
180 }
181 #endif
182 
183 const struct xattr_handler f2fs_xattr_user_handler = {
184 	.prefix	= XATTR_USER_PREFIX,
185 	.flags	= F2FS_XATTR_INDEX_USER,
186 	.list	= f2fs_xattr_generic_list,
187 	.get	= f2fs_xattr_generic_get,
188 	.set	= f2fs_xattr_generic_set,
189 };
190 
191 const struct xattr_handler f2fs_xattr_trusted_handler = {
192 	.prefix	= XATTR_TRUSTED_PREFIX,
193 	.flags	= F2FS_XATTR_INDEX_TRUSTED,
194 	.list	= f2fs_xattr_generic_list,
195 	.get	= f2fs_xattr_generic_get,
196 	.set	= f2fs_xattr_generic_set,
197 };
198 
199 const struct xattr_handler f2fs_xattr_advise_handler = {
200 	.prefix = F2FS_SYSTEM_ADVISE_PREFIX,
201 	.flags	= F2FS_XATTR_INDEX_ADVISE,
202 	.list   = f2fs_xattr_advise_list,
203 	.get    = f2fs_xattr_advise_get,
204 	.set    = f2fs_xattr_advise_set,
205 };
206 
207 const struct xattr_handler f2fs_xattr_security_handler = {
208 	.prefix	= XATTR_SECURITY_PREFIX,
209 	.flags	= F2FS_XATTR_INDEX_SECURITY,
210 	.list	= f2fs_xattr_generic_list,
211 	.get	= f2fs_xattr_generic_get,
212 	.set	= f2fs_xattr_generic_set,
213 };
214 
215 static const struct xattr_handler *f2fs_xattr_handler_map[] = {
216 	[F2FS_XATTR_INDEX_USER] = &f2fs_xattr_user_handler,
217 #ifdef CONFIG_F2FS_FS_POSIX_ACL
218 	[F2FS_XATTR_INDEX_POSIX_ACL_ACCESS] = &posix_acl_access_xattr_handler,
219 	[F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
220 #endif
221 	[F2FS_XATTR_INDEX_TRUSTED] = &f2fs_xattr_trusted_handler,
222 #ifdef CONFIG_F2FS_FS_SECURITY
223 	[F2FS_XATTR_INDEX_SECURITY] = &f2fs_xattr_security_handler,
224 #endif
225 	[F2FS_XATTR_INDEX_ADVISE] = &f2fs_xattr_advise_handler,
226 };
227 
228 const struct xattr_handler *f2fs_xattr_handlers[] = {
229 	&f2fs_xattr_user_handler,
230 #ifdef CONFIG_F2FS_FS_POSIX_ACL
231 	&posix_acl_access_xattr_handler,
232 	&posix_acl_default_xattr_handler,
233 #endif
234 	&f2fs_xattr_trusted_handler,
235 #ifdef CONFIG_F2FS_FS_SECURITY
236 	&f2fs_xattr_security_handler,
237 #endif
238 	&f2fs_xattr_advise_handler,
239 	NULL,
240 };
241 
242 static inline const struct xattr_handler *f2fs_xattr_handler(int index)
243 {
244 	const struct xattr_handler *handler = NULL;
245 
246 	if (index > 0 && index < ARRAY_SIZE(f2fs_xattr_handler_map))
247 		handler = f2fs_xattr_handler_map[index];
248 	return handler;
249 }
250 
251 static struct f2fs_xattr_entry *__find_xattr(void *base_addr, int index,
252 					size_t len, const char *name)
253 {
254 	struct f2fs_xattr_entry *entry;
255 
256 	list_for_each_xattr(entry, base_addr) {
257 		if (entry->e_name_index != index)
258 			continue;
259 		if (entry->e_name_len != len)
260 			continue;
261 		if (!memcmp(entry->e_name, name, len))
262 			break;
263 	}
264 	return entry;
265 }
266 
267 static void *read_all_xattrs(struct inode *inode, struct page *ipage)
268 {
269 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
270 	struct f2fs_xattr_header *header;
271 	size_t size = PAGE_SIZE, inline_size = 0;
272 	void *txattr_addr;
273 
274 	inline_size = inline_xattr_size(inode);
275 
276 	txattr_addr = kzalloc(inline_size + size, GFP_F2FS_ZERO);
277 	if (!txattr_addr)
278 		return NULL;
279 
280 	/* read from inline xattr */
281 	if (inline_size) {
282 		struct page *page = NULL;
283 		void *inline_addr;
284 
285 		if (ipage) {
286 			inline_addr = inline_xattr_addr(ipage);
287 		} else {
288 			page = get_node_page(sbi, inode->i_ino);
289 			if (IS_ERR(page))
290 				goto fail;
291 			inline_addr = inline_xattr_addr(page);
292 		}
293 		memcpy(txattr_addr, inline_addr, inline_size);
294 		f2fs_put_page(page, 1);
295 	}
296 
297 	/* read from xattr node block */
298 	if (F2FS_I(inode)->i_xattr_nid) {
299 		struct page *xpage;
300 		void *xattr_addr;
301 
302 		/* The inode already has an extended attribute block. */
303 		xpage = get_node_page(sbi, F2FS_I(inode)->i_xattr_nid);
304 		if (IS_ERR(xpage))
305 			goto fail;
306 
307 		xattr_addr = page_address(xpage);
308 		memcpy(txattr_addr + inline_size, xattr_addr, PAGE_SIZE);
309 		f2fs_put_page(xpage, 1);
310 	}
311 
312 	header = XATTR_HDR(txattr_addr);
313 
314 	/* never been allocated xattrs */
315 	if (le32_to_cpu(header->h_magic) != F2FS_XATTR_MAGIC) {
316 		header->h_magic = cpu_to_le32(F2FS_XATTR_MAGIC);
317 		header->h_refcount = cpu_to_le32(1);
318 	}
319 	return txattr_addr;
320 fail:
321 	kzfree(txattr_addr);
322 	return NULL;
323 }
324 
325 static inline int write_all_xattrs(struct inode *inode, __u32 hsize,
326 				void *txattr_addr, struct page *ipage)
327 {
328 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
329 	size_t inline_size = 0;
330 	void *xattr_addr;
331 	struct page *xpage;
332 	nid_t new_nid = 0;
333 	int err;
334 
335 	inline_size = inline_xattr_size(inode);
336 
337 	if (hsize > inline_size && !F2FS_I(inode)->i_xattr_nid)
338 		if (!alloc_nid(sbi, &new_nid))
339 			return -ENOSPC;
340 
341 	/* write to inline xattr */
342 	if (inline_size) {
343 		struct page *page = NULL;
344 		void *inline_addr;
345 
346 		if (ipage) {
347 			inline_addr = inline_xattr_addr(ipage);
348 			f2fs_wait_on_page_writeback(ipage, NODE);
349 		} else {
350 			page = get_node_page(sbi, inode->i_ino);
351 			if (IS_ERR(page)) {
352 				alloc_nid_failed(sbi, new_nid);
353 				return PTR_ERR(page);
354 			}
355 			inline_addr = inline_xattr_addr(page);
356 			f2fs_wait_on_page_writeback(page, NODE);
357 		}
358 		memcpy(inline_addr, txattr_addr, inline_size);
359 		f2fs_put_page(page, 1);
360 
361 		/* no need to use xattr node block */
362 		if (hsize <= inline_size) {
363 			err = truncate_xattr_node(inode, ipage);
364 			alloc_nid_failed(sbi, new_nid);
365 			return err;
366 		}
367 	}
368 
369 	/* write to xattr node block */
370 	if (F2FS_I(inode)->i_xattr_nid) {
371 		xpage = get_node_page(sbi, F2FS_I(inode)->i_xattr_nid);
372 		if (IS_ERR(xpage)) {
373 			alloc_nid_failed(sbi, new_nid);
374 			return PTR_ERR(xpage);
375 		}
376 		f2fs_bug_on(sbi, new_nid);
377 		f2fs_wait_on_page_writeback(xpage, NODE);
378 	} else {
379 		struct dnode_of_data dn;
380 		set_new_dnode(&dn, inode, NULL, NULL, new_nid);
381 		xpage = new_node_page(&dn, XATTR_NODE_OFFSET, ipage);
382 		if (IS_ERR(xpage)) {
383 			alloc_nid_failed(sbi, new_nid);
384 			return PTR_ERR(xpage);
385 		}
386 		alloc_nid_done(sbi, new_nid);
387 	}
388 
389 	xattr_addr = page_address(xpage);
390 	memcpy(xattr_addr, txattr_addr + inline_size, PAGE_SIZE -
391 						sizeof(struct node_footer));
392 	set_page_dirty(xpage);
393 	f2fs_put_page(xpage, 1);
394 
395 	/* need to checkpoint during fsync */
396 	F2FS_I(inode)->xattr_ver = cur_cp_version(F2FS_CKPT(sbi));
397 	return 0;
398 }
399 
400 int f2fs_getxattr(struct inode *inode, int index, const char *name,
401 		void *buffer, size_t buffer_size, struct page *ipage)
402 {
403 	struct f2fs_xattr_entry *entry;
404 	void *base_addr;
405 	int error = 0;
406 	size_t size, len;
407 
408 	if (name == NULL)
409 		return -EINVAL;
410 
411 	len = strlen(name);
412 	if (len > F2FS_NAME_LEN)
413 		return -ERANGE;
414 
415 	base_addr = read_all_xattrs(inode, ipage);
416 	if (!base_addr)
417 		return -ENOMEM;
418 
419 	entry = __find_xattr(base_addr, index, len, name);
420 	if (IS_XATTR_LAST_ENTRY(entry)) {
421 		error = -ENODATA;
422 		goto cleanup;
423 	}
424 
425 	size = le16_to_cpu(entry->e_value_size);
426 
427 	if (buffer && size > buffer_size) {
428 		error = -ERANGE;
429 		goto cleanup;
430 	}
431 
432 	if (buffer) {
433 		char *pval = entry->e_name + entry->e_name_len;
434 		memcpy(buffer, pval, size);
435 	}
436 	error = size;
437 
438 cleanup:
439 	kzfree(base_addr);
440 	return error;
441 }
442 
443 ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
444 {
445 	struct inode *inode = dentry->d_inode;
446 	struct f2fs_xattr_entry *entry;
447 	void *base_addr;
448 	int error = 0;
449 	size_t rest = buffer_size;
450 
451 	base_addr = read_all_xattrs(inode, NULL);
452 	if (!base_addr)
453 		return -ENOMEM;
454 
455 	list_for_each_xattr(entry, base_addr) {
456 		const struct xattr_handler *handler =
457 			f2fs_xattr_handler(entry->e_name_index);
458 		size_t size;
459 
460 		if (!handler)
461 			continue;
462 
463 		size = handler->list(dentry, buffer, rest, entry->e_name,
464 				entry->e_name_len, handler->flags);
465 		if (buffer && size > rest) {
466 			error = -ERANGE;
467 			goto cleanup;
468 		}
469 
470 		if (buffer)
471 			buffer += size;
472 		rest -= size;
473 	}
474 	error = buffer_size - rest;
475 cleanup:
476 	kzfree(base_addr);
477 	return error;
478 }
479 
480 static int __f2fs_setxattr(struct inode *inode, int index,
481 			const char *name, const void *value, size_t size,
482 			struct page *ipage, int flags)
483 {
484 	struct f2fs_inode_info *fi = F2FS_I(inode);
485 	struct f2fs_xattr_entry *here, *last;
486 	void *base_addr;
487 	int found, newsize;
488 	size_t len;
489 	__u32 new_hsize;
490 	int error = -ENOMEM;
491 
492 	if (name == NULL)
493 		return -EINVAL;
494 
495 	if (value == NULL)
496 		size = 0;
497 
498 	len = strlen(name);
499 
500 	if (len > F2FS_NAME_LEN || size > MAX_VALUE_LEN(inode))
501 		return -ERANGE;
502 
503 	base_addr = read_all_xattrs(inode, ipage);
504 	if (!base_addr)
505 		goto exit;
506 
507 	/* find entry with wanted name. */
508 	here = __find_xattr(base_addr, index, len, name);
509 
510 	found = IS_XATTR_LAST_ENTRY(here) ? 0 : 1;
511 
512 	if ((flags & XATTR_REPLACE) && !found) {
513 		error = -ENODATA;
514 		goto exit;
515 	} else if ((flags & XATTR_CREATE) && found) {
516 		error = -EEXIST;
517 		goto exit;
518 	}
519 
520 	last = here;
521 	while (!IS_XATTR_LAST_ENTRY(last))
522 		last = XATTR_NEXT_ENTRY(last);
523 
524 	newsize = XATTR_ALIGN(sizeof(struct f2fs_xattr_entry) + len + size);
525 
526 	/* 1. Check space */
527 	if (value) {
528 		int free;
529 		/*
530 		 * If value is NULL, it is remove operation.
531 		 * In case of update operation, we calculate free.
532 		 */
533 		free = MIN_OFFSET(inode) - ((char *)last - (char *)base_addr);
534 		if (found)
535 			free = free + ENTRY_SIZE(here);
536 
537 		if (unlikely(free < newsize)) {
538 			error = -ENOSPC;
539 			goto exit;
540 		}
541 	}
542 
543 	/* 2. Remove old entry */
544 	if (found) {
545 		/*
546 		 * If entry is found, remove old entry.
547 		 * If not found, remove operation is not needed.
548 		 */
549 		struct f2fs_xattr_entry *next = XATTR_NEXT_ENTRY(here);
550 		int oldsize = ENTRY_SIZE(here);
551 
552 		memmove(here, next, (char *)last - (char *)next);
553 		last = (struct f2fs_xattr_entry *)((char *)last - oldsize);
554 		memset(last, 0, oldsize);
555 	}
556 
557 	new_hsize = (char *)last - (char *)base_addr;
558 
559 	/* 3. Write new entry */
560 	if (value) {
561 		char *pval;
562 		/*
563 		 * Before we come here, old entry is removed.
564 		 * We just write new entry.
565 		 */
566 		memset(last, 0, newsize);
567 		last->e_name_index = index;
568 		last->e_name_len = len;
569 		memcpy(last->e_name, name, len);
570 		pval = last->e_name + len;
571 		memcpy(pval, value, size);
572 		last->e_value_size = cpu_to_le16(size);
573 		new_hsize += newsize;
574 	}
575 
576 	error = write_all_xattrs(inode, new_hsize, base_addr, ipage);
577 	if (error)
578 		goto exit;
579 
580 	if (is_inode_flag_set(fi, FI_ACL_MODE)) {
581 		inode->i_mode = fi->i_acl_mode;
582 		inode->i_ctime = CURRENT_TIME;
583 		clear_inode_flag(fi, FI_ACL_MODE);
584 	}
585 
586 	if (ipage)
587 		update_inode(inode, ipage);
588 	else
589 		update_inode_page(inode);
590 exit:
591 	kzfree(base_addr);
592 	return error;
593 }
594 
595 int f2fs_setxattr(struct inode *inode, int index, const char *name,
596 				const void *value, size_t size,
597 				struct page *ipage, int flags)
598 {
599 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
600 	int err;
601 
602 	/* this case is only from init_inode_metadata */
603 	if (ipage)
604 		return __f2fs_setxattr(inode, index, name, value,
605 						size, ipage, flags);
606 	f2fs_balance_fs(sbi);
607 
608 	f2fs_lock_op(sbi);
609 	/* protect xattr_ver */
610 	down_write(&F2FS_I(inode)->i_sem);
611 	err = __f2fs_setxattr(inode, index, name, value, size, ipage, flags);
612 	up_write(&F2FS_I(inode)->i_sem);
613 	f2fs_unlock_op(sbi);
614 
615 	return err;
616 }
617