xref: /openbmc/linux/fs/f2fs/xattr.c (revision f3a8b664) 
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 int f2fs_xattr_generic_get(const struct xattr_handler *handler,
29 		struct dentry *unused, struct inode *inode,
30 		const char *name, void *buffer, size_t size)
31 {
32 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
33 
34 	switch (handler->flags) {
35 	case F2FS_XATTR_INDEX_USER:
36 		if (!test_opt(sbi, XATTR_USER))
37 			return -EOPNOTSUPP;
38 		break;
39 	case F2FS_XATTR_INDEX_TRUSTED:
40 		if (!capable(CAP_SYS_ADMIN))
41 			return -EPERM;
42 		break;
43 	case F2FS_XATTR_INDEX_SECURITY:
44 		break;
45 	default:
46 		return -EINVAL;
47 	}
48 	return f2fs_getxattr(inode, handler->flags, name,
49 			     buffer, size, NULL);
50 }
51 
52 static int f2fs_xattr_generic_set(const struct xattr_handler *handler,
53 		struct dentry *unused, struct inode *inode,
54 		const char *name, const void *value,
55 		size_t size, int flags)
56 {
57 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
58 
59 	switch (handler->flags) {
60 	case F2FS_XATTR_INDEX_USER:
61 		if (!test_opt(sbi, XATTR_USER))
62 			return -EOPNOTSUPP;
63 		break;
64 	case F2FS_XATTR_INDEX_TRUSTED:
65 		if (!capable(CAP_SYS_ADMIN))
66 			return -EPERM;
67 		break;
68 	case F2FS_XATTR_INDEX_SECURITY:
69 		break;
70 	default:
71 		return -EINVAL;
72 	}
73 	return f2fs_setxattr(inode, handler->flags, name,
74 					value, size, NULL, flags);
75 }
76 
77 static bool f2fs_xattr_user_list(struct dentry *dentry)
78 {
79 	struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
80 
81 	return test_opt(sbi, XATTR_USER);
82 }
83 
84 static bool f2fs_xattr_trusted_list(struct dentry *dentry)
85 {
86 	return capable(CAP_SYS_ADMIN);
87 }
88 
89 static int f2fs_xattr_advise_get(const struct xattr_handler *handler,
90 		struct dentry *unused, struct inode *inode,
91 		const char *name, void *buffer, size_t size)
92 {
93 	if (buffer)
94 		*((char *)buffer) = F2FS_I(inode)->i_advise;
95 	return sizeof(char);
96 }
97 
98 static int f2fs_xattr_advise_set(const struct xattr_handler *handler,
99 		struct dentry *unused, struct inode *inode,
100 		const char *name, const void *value,
101 		size_t size, int flags)
102 {
103 	if (!inode_owner_or_capable(inode))
104 		return -EPERM;
105 	if (value == NULL)
106 		return -EINVAL;
107 
108 	F2FS_I(inode)->i_advise |= *(char *)value;
109 	f2fs_mark_inode_dirty_sync(inode);
110 	return 0;
111 }
112 
113 #ifdef CONFIG_F2FS_FS_SECURITY
114 static int f2fs_initxattrs(struct inode *inode, const struct xattr *xattr_array,
115 		void *page)
116 {
117 	const struct xattr *xattr;
118 	int err = 0;
119 
120 	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
121 		err = f2fs_setxattr(inode, F2FS_XATTR_INDEX_SECURITY,
122 				xattr->name, xattr->value,
123 				xattr->value_len, (struct page *)page, 0);
124 		if (err < 0)
125 			break;
126 	}
127 	return err;
128 }
129 
130 int f2fs_init_security(struct inode *inode, struct inode *dir,
131 				const struct qstr *qstr, struct page *ipage)
132 {
133 	return security_inode_init_security(inode, dir, qstr,
134 				&f2fs_initxattrs, ipage);
135 }
136 #endif
137 
138 const struct xattr_handler f2fs_xattr_user_handler = {
139 	.prefix	= XATTR_USER_PREFIX,
140 	.flags	= F2FS_XATTR_INDEX_USER,
141 	.list	= f2fs_xattr_user_list,
142 	.get	= f2fs_xattr_generic_get,
143 	.set	= f2fs_xattr_generic_set,
144 };
145 
146 const struct xattr_handler f2fs_xattr_trusted_handler = {
147 	.prefix	= XATTR_TRUSTED_PREFIX,
148 	.flags	= F2FS_XATTR_INDEX_TRUSTED,
149 	.list	= f2fs_xattr_trusted_list,
150 	.get	= f2fs_xattr_generic_get,
151 	.set	= f2fs_xattr_generic_set,
152 };
153 
154 const struct xattr_handler f2fs_xattr_advise_handler = {
155 	.name	= F2FS_SYSTEM_ADVISE_NAME,
156 	.flags	= F2FS_XATTR_INDEX_ADVISE,
157 	.get    = f2fs_xattr_advise_get,
158 	.set    = f2fs_xattr_advise_set,
159 };
160 
161 const struct xattr_handler f2fs_xattr_security_handler = {
162 	.prefix	= XATTR_SECURITY_PREFIX,
163 	.flags	= F2FS_XATTR_INDEX_SECURITY,
164 	.get	= f2fs_xattr_generic_get,
165 	.set	= f2fs_xattr_generic_set,
166 };
167 
168 static const struct xattr_handler *f2fs_xattr_handler_map[] = {
169 	[F2FS_XATTR_INDEX_USER] = &f2fs_xattr_user_handler,
170 #ifdef CONFIG_F2FS_FS_POSIX_ACL
171 	[F2FS_XATTR_INDEX_POSIX_ACL_ACCESS] = &posix_acl_access_xattr_handler,
172 	[F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
173 #endif
174 	[F2FS_XATTR_INDEX_TRUSTED] = &f2fs_xattr_trusted_handler,
175 #ifdef CONFIG_F2FS_FS_SECURITY
176 	[F2FS_XATTR_INDEX_SECURITY] = &f2fs_xattr_security_handler,
177 #endif
178 	[F2FS_XATTR_INDEX_ADVISE] = &f2fs_xattr_advise_handler,
179 };
180 
181 const struct xattr_handler *f2fs_xattr_handlers[] = {
182 	&f2fs_xattr_user_handler,
183 #ifdef CONFIG_F2FS_FS_POSIX_ACL
184 	&posix_acl_access_xattr_handler,
185 	&posix_acl_default_xattr_handler,
186 #endif
187 	&f2fs_xattr_trusted_handler,
188 #ifdef CONFIG_F2FS_FS_SECURITY
189 	&f2fs_xattr_security_handler,
190 #endif
191 	&f2fs_xattr_advise_handler,
192 	NULL,
193 };
194 
195 static inline const struct xattr_handler *f2fs_xattr_handler(int index)
196 {
197 	const struct xattr_handler *handler = NULL;
198 
199 	if (index > 0 && index < ARRAY_SIZE(f2fs_xattr_handler_map))
200 		handler = f2fs_xattr_handler_map[index];
201 	return handler;
202 }
203 
204 static struct f2fs_xattr_entry *__find_xattr(void *base_addr, int index,
205 					size_t len, const char *name)
206 {
207 	struct f2fs_xattr_entry *entry;
208 
209 	list_for_each_xattr(entry, base_addr) {
210 		if (entry->e_name_index != index)
211 			continue;
212 		if (entry->e_name_len != len)
213 			continue;
214 		if (!memcmp(entry->e_name, name, len))
215 			break;
216 	}
217 	return entry;
218 }
219 
220 static int read_all_xattrs(struct inode *inode, struct page *ipage,
221 							void **base_addr)
222 {
223 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
224 	struct f2fs_xattr_header *header;
225 	size_t size = PAGE_SIZE, inline_size = 0;
226 	void *txattr_addr;
227 	int err;
228 
229 	inline_size = inline_xattr_size(inode);
230 
231 	txattr_addr = kzalloc(inline_size + size, GFP_F2FS_ZERO);
232 	if (!txattr_addr)
233 		return -ENOMEM;
234 
235 	/* read from inline xattr */
236 	if (inline_size) {
237 		struct page *page = NULL;
238 		void *inline_addr;
239 
240 		if (ipage) {
241 			inline_addr = inline_xattr_addr(ipage);
242 		} else {
243 			page = get_node_page(sbi, inode->i_ino);
244 			if (IS_ERR(page)) {
245 				err = PTR_ERR(page);
246 				goto fail;
247 			}
248 			inline_addr = inline_xattr_addr(page);
249 		}
250 		memcpy(txattr_addr, inline_addr, inline_size);
251 		f2fs_put_page(page, 1);
252 	}
253 
254 	/* read from xattr node block */
255 	if (F2FS_I(inode)->i_xattr_nid) {
256 		struct page *xpage;
257 		void *xattr_addr;
258 
259 		/* The inode already has an extended attribute block. */
260 		xpage = get_node_page(sbi, F2FS_I(inode)->i_xattr_nid);
261 		if (IS_ERR(xpage)) {
262 			err = PTR_ERR(xpage);
263 			goto fail;
264 		}
265 
266 		xattr_addr = page_address(xpage);
267 		memcpy(txattr_addr + inline_size, xattr_addr, PAGE_SIZE);
268 		f2fs_put_page(xpage, 1);
269 	}
270 
271 	header = XATTR_HDR(txattr_addr);
272 
273 	/* never been allocated xattrs */
274 	if (le32_to_cpu(header->h_magic) != F2FS_XATTR_MAGIC) {
275 		header->h_magic = cpu_to_le32(F2FS_XATTR_MAGIC);
276 		header->h_refcount = cpu_to_le32(1);
277 	}
278 	*base_addr = txattr_addr;
279 	return 0;
280 fail:
281 	kzfree(txattr_addr);
282 	return err;
283 }
284 
285 static inline int write_all_xattrs(struct inode *inode, __u32 hsize,
286 				void *txattr_addr, struct page *ipage)
287 {
288 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
289 	size_t inline_size = 0;
290 	void *xattr_addr;
291 	struct page *xpage;
292 	nid_t new_nid = 0;
293 	int err;
294 
295 	inline_size = inline_xattr_size(inode);
296 
297 	if (hsize > inline_size && !F2FS_I(inode)->i_xattr_nid)
298 		if (!alloc_nid(sbi, &new_nid))
299 			return -ENOSPC;
300 
301 	/* write to inline xattr */
302 	if (inline_size) {
303 		struct page *page = NULL;
304 		void *inline_addr;
305 
306 		if (ipage) {
307 			inline_addr = inline_xattr_addr(ipage);
308 			f2fs_wait_on_page_writeback(ipage, NODE, true);
309 			set_page_dirty(ipage);
310 		} else {
311 			page = get_node_page(sbi, inode->i_ino);
312 			if (IS_ERR(page)) {
313 				alloc_nid_failed(sbi, new_nid);
314 				return PTR_ERR(page);
315 			}
316 			inline_addr = inline_xattr_addr(page);
317 			f2fs_wait_on_page_writeback(page, NODE, true);
318 		}
319 		memcpy(inline_addr, txattr_addr, inline_size);
320 		f2fs_put_page(page, 1);
321 
322 		/* no need to use xattr node block */
323 		if (hsize <= inline_size) {
324 			err = truncate_xattr_node(inode, ipage);
325 			alloc_nid_failed(sbi, new_nid);
326 			return err;
327 		}
328 	}
329 
330 	/* write to xattr node block */
331 	if (F2FS_I(inode)->i_xattr_nid) {
332 		xpage = get_node_page(sbi, F2FS_I(inode)->i_xattr_nid);
333 		if (IS_ERR(xpage)) {
334 			alloc_nid_failed(sbi, new_nid);
335 			return PTR_ERR(xpage);
336 		}
337 		f2fs_bug_on(sbi, new_nid);
338 		f2fs_wait_on_page_writeback(xpage, NODE, true);
339 	} else {
340 		struct dnode_of_data dn;
341 		set_new_dnode(&dn, inode, NULL, NULL, new_nid);
342 		xpage = new_node_page(&dn, XATTR_NODE_OFFSET, ipage);
343 		if (IS_ERR(xpage)) {
344 			alloc_nid_failed(sbi, new_nid);
345 			return PTR_ERR(xpage);
346 		}
347 		alloc_nid_done(sbi, new_nid);
348 	}
349 
350 	xattr_addr = page_address(xpage);
351 	memcpy(xattr_addr, txattr_addr + inline_size, PAGE_SIZE -
352 						sizeof(struct node_footer));
353 	set_page_dirty(xpage);
354 	f2fs_put_page(xpage, 1);
355 
356 	/* need to checkpoint during fsync */
357 	F2FS_I(inode)->xattr_ver = cur_cp_version(F2FS_CKPT(sbi));
358 	return 0;
359 }
360 
361 int f2fs_getxattr(struct inode *inode, int index, const char *name,
362 		void *buffer, size_t buffer_size, struct page *ipage)
363 {
364 	struct f2fs_xattr_entry *entry;
365 	void *base_addr;
366 	int error = 0;
367 	size_t size, len;
368 
369 	if (name == NULL)
370 		return -EINVAL;
371 
372 	len = strlen(name);
373 	if (len > F2FS_NAME_LEN)
374 		return -ERANGE;
375 
376 	error = read_all_xattrs(inode, ipage, &base_addr);
377 	if (error)
378 		return error;
379 
380 	entry = __find_xattr(base_addr, index, len, name);
381 	if (IS_XATTR_LAST_ENTRY(entry)) {
382 		error = -ENODATA;
383 		goto cleanup;
384 	}
385 
386 	size = le16_to_cpu(entry->e_value_size);
387 
388 	if (buffer && size > buffer_size) {
389 		error = -ERANGE;
390 		goto cleanup;
391 	}
392 
393 	if (buffer) {
394 		char *pval = entry->e_name + entry->e_name_len;
395 		memcpy(buffer, pval, size);
396 	}
397 	error = size;
398 
399 cleanup:
400 	kzfree(base_addr);
401 	return error;
402 }
403 
404 ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
405 {
406 	struct inode *inode = d_inode(dentry);
407 	struct f2fs_xattr_entry *entry;
408 	void *base_addr;
409 	int error = 0;
410 	size_t rest = buffer_size;
411 
412 	error = read_all_xattrs(inode, NULL, &base_addr);
413 	if (error)
414 		return error;
415 
416 	list_for_each_xattr(entry, base_addr) {
417 		const struct xattr_handler *handler =
418 			f2fs_xattr_handler(entry->e_name_index);
419 		const char *prefix;
420 		size_t prefix_len;
421 		size_t size;
422 
423 		if (!handler || (handler->list && !handler->list(dentry)))
424 			continue;
425 
426 		prefix = handler->prefix ?: handler->name;
427 		prefix_len = strlen(prefix);
428 		size = prefix_len + entry->e_name_len + 1;
429 		if (buffer) {
430 			if (size > rest) {
431 				error = -ERANGE;
432 				goto cleanup;
433 			}
434 			memcpy(buffer, prefix, prefix_len);
435 			buffer += prefix_len;
436 			memcpy(buffer, entry->e_name, entry->e_name_len);
437 			buffer += entry->e_name_len;
438 			*buffer++ = 0;
439 		}
440 		rest -= size;
441 	}
442 	error = buffer_size - rest;
443 cleanup:
444 	kzfree(base_addr);
445 	return error;
446 }
447 
448 static int __f2fs_setxattr(struct inode *inode, int index,
449 			const char *name, const void *value, size_t size,
450 			struct page *ipage, int flags)
451 {
452 	struct f2fs_xattr_entry *here, *last;
453 	void *base_addr;
454 	int found, newsize;
455 	size_t len;
456 	__u32 new_hsize;
457 	int error = 0;
458 
459 	if (name == NULL)
460 		return -EINVAL;
461 
462 	if (value == NULL)
463 		size = 0;
464 
465 	len = strlen(name);
466 
467 	if (len > F2FS_NAME_LEN)
468 		return -ERANGE;
469 
470 	if (size > MAX_VALUE_LEN(inode))
471 		return -E2BIG;
472 
473 	error = read_all_xattrs(inode, ipage, &base_addr);
474 	if (error)
475 		return error;
476 
477 	/* find entry with wanted name. */
478 	here = __find_xattr(base_addr, index, len, name);
479 
480 	found = IS_XATTR_LAST_ENTRY(here) ? 0 : 1;
481 
482 	if ((flags & XATTR_REPLACE) && !found) {
483 		error = -ENODATA;
484 		goto exit;
485 	} else if ((flags & XATTR_CREATE) && found) {
486 		error = -EEXIST;
487 		goto exit;
488 	}
489 
490 	last = here;
491 	while (!IS_XATTR_LAST_ENTRY(last))
492 		last = XATTR_NEXT_ENTRY(last);
493 
494 	newsize = XATTR_ALIGN(sizeof(struct f2fs_xattr_entry) + len + size);
495 
496 	/* 1. Check space */
497 	if (value) {
498 		int free;
499 		/*
500 		 * If value is NULL, it is remove operation.
501 		 * In case of update operation, we calculate free.
502 		 */
503 		free = MIN_OFFSET(inode) - ((char *)last - (char *)base_addr);
504 		if (found)
505 			free = free + ENTRY_SIZE(here);
506 
507 		if (unlikely(free < newsize)) {
508 			error = -E2BIG;
509 			goto exit;
510 		}
511 	}
512 
513 	/* 2. Remove old entry */
514 	if (found) {
515 		/*
516 		 * If entry is found, remove old entry.
517 		 * If not found, remove operation is not needed.
518 		 */
519 		struct f2fs_xattr_entry *next = XATTR_NEXT_ENTRY(here);
520 		int oldsize = ENTRY_SIZE(here);
521 
522 		memmove(here, next, (char *)last - (char *)next);
523 		last = (struct f2fs_xattr_entry *)((char *)last - oldsize);
524 		memset(last, 0, oldsize);
525 	}
526 
527 	new_hsize = (char *)last - (char *)base_addr;
528 
529 	/* 3. Write new entry */
530 	if (value) {
531 		char *pval;
532 		/*
533 		 * Before we come here, old entry is removed.
534 		 * We just write new entry.
535 		 */
536 		last->e_name_index = index;
537 		last->e_name_len = len;
538 		memcpy(last->e_name, name, len);
539 		pval = last->e_name + len;
540 		memcpy(pval, value, size);
541 		last->e_value_size = cpu_to_le16(size);
542 		new_hsize += newsize;
543 	}
544 
545 	error = write_all_xattrs(inode, new_hsize, base_addr, ipage);
546 	if (error)
547 		goto exit;
548 
549 	if (is_inode_flag_set(inode, FI_ACL_MODE)) {
550 		inode->i_mode = F2FS_I(inode)->i_acl_mode;
551 		inode->i_ctime = current_time(inode);
552 		clear_inode_flag(inode, FI_ACL_MODE);
553 	}
554 	if (index == F2FS_XATTR_INDEX_ENCRYPTION &&
555 			!strcmp(name, F2FS_XATTR_NAME_ENCRYPTION_CONTEXT))
556 		f2fs_set_encrypted_inode(inode);
557 	f2fs_mark_inode_dirty_sync(inode);
558 	if (!error && S_ISDIR(inode->i_mode))
559 		set_sbi_flag(F2FS_I_SB(inode), SBI_NEED_CP);
560 exit:
561 	kzfree(base_addr);
562 	return error;
563 }
564 
565 int f2fs_setxattr(struct inode *inode, int index, const char *name,
566 				const void *value, size_t size,
567 				struct page *ipage, int flags)
568 {
569 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
570 	int err;
571 
572 	/* this case is only from init_inode_metadata */
573 	if (ipage)
574 		return __f2fs_setxattr(inode, index, name, value,
575 						size, ipage, flags);
576 	f2fs_balance_fs(sbi, true);
577 
578 	f2fs_lock_op(sbi);
579 	/* protect xattr_ver */
580 	down_write(&F2FS_I(inode)->i_sem);
581 	err = __f2fs_setxattr(inode, index, name, value, size, ipage, flags);
582 	up_write(&F2FS_I(inode)->i_sem);
583 	f2fs_unlock_op(sbi);
584 
585 	f2fs_update_time(sbi, REQ_TIME);
586 	return err;
587 }
588