xref: /openbmc/linux/fs/f2fs/xattr.c (revision 293d5b43) 
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 void *read_all_xattrs(struct inode *inode, struct page *ipage)
221 {
222 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
223 	struct f2fs_xattr_header *header;
224 	size_t size = PAGE_SIZE, inline_size = 0;
225 	void *txattr_addr;
226 
227 	inline_size = inline_xattr_size(inode);
228 
229 	txattr_addr = kzalloc(inline_size + size, GFP_F2FS_ZERO);
230 	if (!txattr_addr)
231 		return NULL;
232 
233 	/* read from inline xattr */
234 	if (inline_size) {
235 		struct page *page = NULL;
236 		void *inline_addr;
237 
238 		if (ipage) {
239 			inline_addr = inline_xattr_addr(ipage);
240 		} else {
241 			page = get_node_page(sbi, inode->i_ino);
242 			if (IS_ERR(page))
243 				goto fail;
244 			inline_addr = inline_xattr_addr(page);
245 		}
246 		memcpy(txattr_addr, inline_addr, inline_size);
247 		f2fs_put_page(page, 1);
248 	}
249 
250 	/* read from xattr node block */
251 	if (F2FS_I(inode)->i_xattr_nid) {
252 		struct page *xpage;
253 		void *xattr_addr;
254 
255 		/* The inode already has an extended attribute block. */
256 		xpage = get_node_page(sbi, F2FS_I(inode)->i_xattr_nid);
257 		if (IS_ERR(xpage))
258 			goto fail;
259 
260 		xattr_addr = page_address(xpage);
261 		memcpy(txattr_addr + inline_size, xattr_addr, PAGE_SIZE);
262 		f2fs_put_page(xpage, 1);
263 	}
264 
265 	header = XATTR_HDR(txattr_addr);
266 
267 	/* never been allocated xattrs */
268 	if (le32_to_cpu(header->h_magic) != F2FS_XATTR_MAGIC) {
269 		header->h_magic = cpu_to_le32(F2FS_XATTR_MAGIC);
270 		header->h_refcount = cpu_to_le32(1);
271 	}
272 	return txattr_addr;
273 fail:
274 	kzfree(txattr_addr);
275 	return NULL;
276 }
277 
278 static inline int write_all_xattrs(struct inode *inode, __u32 hsize,
279 				void *txattr_addr, struct page *ipage)
280 {
281 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
282 	size_t inline_size = 0;
283 	void *xattr_addr;
284 	struct page *xpage;
285 	nid_t new_nid = 0;
286 	int err;
287 
288 	inline_size = inline_xattr_size(inode);
289 
290 	if (hsize > inline_size && !F2FS_I(inode)->i_xattr_nid)
291 		if (!alloc_nid(sbi, &new_nid))
292 			return -ENOSPC;
293 
294 	/* write to inline xattr */
295 	if (inline_size) {
296 		struct page *page = NULL;
297 		void *inline_addr;
298 
299 		if (ipage) {
300 			inline_addr = inline_xattr_addr(ipage);
301 			f2fs_wait_on_page_writeback(ipage, NODE, true);
302 			set_page_dirty(ipage);
303 		} else {
304 			page = get_node_page(sbi, inode->i_ino);
305 			if (IS_ERR(page)) {
306 				alloc_nid_failed(sbi, new_nid);
307 				return PTR_ERR(page);
308 			}
309 			inline_addr = inline_xattr_addr(page);
310 			f2fs_wait_on_page_writeback(page, NODE, true);
311 		}
312 		memcpy(inline_addr, txattr_addr, inline_size);
313 		f2fs_put_page(page, 1);
314 
315 		/* no need to use xattr node block */
316 		if (hsize <= inline_size) {
317 			err = truncate_xattr_node(inode, ipage);
318 			alloc_nid_failed(sbi, new_nid);
319 			return err;
320 		}
321 	}
322 
323 	/* write to xattr node block */
324 	if (F2FS_I(inode)->i_xattr_nid) {
325 		xpage = get_node_page(sbi, F2FS_I(inode)->i_xattr_nid);
326 		if (IS_ERR(xpage)) {
327 			alloc_nid_failed(sbi, new_nid);
328 			return PTR_ERR(xpage);
329 		}
330 		f2fs_bug_on(sbi, new_nid);
331 		f2fs_wait_on_page_writeback(xpage, NODE, true);
332 	} else {
333 		struct dnode_of_data dn;
334 		set_new_dnode(&dn, inode, NULL, NULL, new_nid);
335 		xpage = new_node_page(&dn, XATTR_NODE_OFFSET, ipage);
336 		if (IS_ERR(xpage)) {
337 			alloc_nid_failed(sbi, new_nid);
338 			return PTR_ERR(xpage);
339 		}
340 		alloc_nid_done(sbi, new_nid);
341 	}
342 
343 	xattr_addr = page_address(xpage);
344 	memcpy(xattr_addr, txattr_addr + inline_size, PAGE_SIZE -
345 						sizeof(struct node_footer));
346 	set_page_dirty(xpage);
347 	f2fs_put_page(xpage, 1);
348 
349 	/* need to checkpoint during fsync */
350 	F2FS_I(inode)->xattr_ver = cur_cp_version(F2FS_CKPT(sbi));
351 	return 0;
352 }
353 
354 int f2fs_getxattr(struct inode *inode, int index, const char *name,
355 		void *buffer, size_t buffer_size, struct page *ipage)
356 {
357 	struct f2fs_xattr_entry *entry;
358 	void *base_addr;
359 	int error = 0;
360 	size_t size, len;
361 
362 	if (name == NULL)
363 		return -EINVAL;
364 
365 	len = strlen(name);
366 	if (len > F2FS_NAME_LEN)
367 		return -ERANGE;
368 
369 	base_addr = read_all_xattrs(inode, ipage);
370 	if (!base_addr)
371 		return -ENOMEM;
372 
373 	entry = __find_xattr(base_addr, index, len, name);
374 	if (IS_XATTR_LAST_ENTRY(entry)) {
375 		error = -ENODATA;
376 		goto cleanup;
377 	}
378 
379 	size = le16_to_cpu(entry->e_value_size);
380 
381 	if (buffer && size > buffer_size) {
382 		error = -ERANGE;
383 		goto cleanup;
384 	}
385 
386 	if (buffer) {
387 		char *pval = entry->e_name + entry->e_name_len;
388 		memcpy(buffer, pval, size);
389 	}
390 	error = size;
391 
392 cleanup:
393 	kzfree(base_addr);
394 	return error;
395 }
396 
397 ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
398 {
399 	struct inode *inode = d_inode(dentry);
400 	struct f2fs_xattr_entry *entry;
401 	void *base_addr;
402 	int error = 0;
403 	size_t rest = buffer_size;
404 
405 	base_addr = read_all_xattrs(inode, NULL);
406 	if (!base_addr)
407 		return -ENOMEM;
408 
409 	list_for_each_xattr(entry, base_addr) {
410 		const struct xattr_handler *handler =
411 			f2fs_xattr_handler(entry->e_name_index);
412 		const char *prefix;
413 		size_t prefix_len;
414 		size_t size;
415 
416 		if (!handler || (handler->list && !handler->list(dentry)))
417 			continue;
418 
419 		prefix = handler->prefix ?: handler->name;
420 		prefix_len = strlen(prefix);
421 		size = prefix_len + entry->e_name_len + 1;
422 		if (buffer) {
423 			if (size > rest) {
424 				error = -ERANGE;
425 				goto cleanup;
426 			}
427 			memcpy(buffer, prefix, prefix_len);
428 			buffer += prefix_len;
429 			memcpy(buffer, entry->e_name, entry->e_name_len);
430 			buffer += entry->e_name_len;
431 			*buffer++ = 0;
432 		}
433 		rest -= size;
434 	}
435 	error = buffer_size - rest;
436 cleanup:
437 	kzfree(base_addr);
438 	return error;
439 }
440 
441 static int __f2fs_setxattr(struct inode *inode, int index,
442 			const char *name, const void *value, size_t size,
443 			struct page *ipage, int flags)
444 {
445 	struct f2fs_xattr_entry *here, *last;
446 	void *base_addr;
447 	int found, newsize;
448 	size_t len;
449 	__u32 new_hsize;
450 	int error = 0;
451 
452 	if (name == NULL)
453 		return -EINVAL;
454 
455 	if (value == NULL)
456 		size = 0;
457 
458 	len = strlen(name);
459 
460 	if (len > F2FS_NAME_LEN)
461 		return -ERANGE;
462 
463 	if (size > MAX_VALUE_LEN(inode))
464 		return -E2BIG;
465 
466 	base_addr = read_all_xattrs(inode, ipage);
467 	if (!base_addr)
468 		return -ENOMEM;
469 
470 	/* find entry with wanted name. */
471 	here = __find_xattr(base_addr, index, len, name);
472 
473 	found = IS_XATTR_LAST_ENTRY(here) ? 0 : 1;
474 
475 	if ((flags & XATTR_REPLACE) && !found) {
476 		error = -ENODATA;
477 		goto exit;
478 	} else if ((flags & XATTR_CREATE) && found) {
479 		error = -EEXIST;
480 		goto exit;
481 	}
482 
483 	last = here;
484 	while (!IS_XATTR_LAST_ENTRY(last))
485 		last = XATTR_NEXT_ENTRY(last);
486 
487 	newsize = XATTR_ALIGN(sizeof(struct f2fs_xattr_entry) + len + size);
488 
489 	/* 1. Check space */
490 	if (value) {
491 		int free;
492 		/*
493 		 * If value is NULL, it is remove operation.
494 		 * In case of update operation, we calculate free.
495 		 */
496 		free = MIN_OFFSET(inode) - ((char *)last - (char *)base_addr);
497 		if (found)
498 			free = free + ENTRY_SIZE(here);
499 
500 		if (unlikely(free < newsize)) {
501 			error = -E2BIG;
502 			goto exit;
503 		}
504 	}
505 
506 	/* 2. Remove old entry */
507 	if (found) {
508 		/*
509 		 * If entry is found, remove old entry.
510 		 * If not found, remove operation is not needed.
511 		 */
512 		struct f2fs_xattr_entry *next = XATTR_NEXT_ENTRY(here);
513 		int oldsize = ENTRY_SIZE(here);
514 
515 		memmove(here, next, (char *)last - (char *)next);
516 		last = (struct f2fs_xattr_entry *)((char *)last - oldsize);
517 		memset(last, 0, oldsize);
518 	}
519 
520 	new_hsize = (char *)last - (char *)base_addr;
521 
522 	/* 3. Write new entry */
523 	if (value) {
524 		char *pval;
525 		/*
526 		 * Before we come here, old entry is removed.
527 		 * We just write new entry.
528 		 */
529 		last->e_name_index = index;
530 		last->e_name_len = len;
531 		memcpy(last->e_name, name, len);
532 		pval = last->e_name + len;
533 		memcpy(pval, value, size);
534 		last->e_value_size = cpu_to_le16(size);
535 		new_hsize += newsize;
536 	}
537 
538 	error = write_all_xattrs(inode, new_hsize, base_addr, ipage);
539 	if (error)
540 		goto exit;
541 
542 	if (is_inode_flag_set(inode, FI_ACL_MODE)) {
543 		inode->i_mode = F2FS_I(inode)->i_acl_mode;
544 		inode->i_ctime = CURRENT_TIME;
545 		clear_inode_flag(inode, FI_ACL_MODE);
546 	}
547 	if (index == F2FS_XATTR_INDEX_ENCRYPTION &&
548 			!strcmp(name, F2FS_XATTR_NAME_ENCRYPTION_CONTEXT))
549 		f2fs_set_encrypted_inode(inode);
550 	f2fs_mark_inode_dirty_sync(inode);
551 exit:
552 	kzfree(base_addr);
553 	return error;
554 }
555 
556 int f2fs_setxattr(struct inode *inode, int index, const char *name,
557 				const void *value, size_t size,
558 				struct page *ipage, int flags)
559 {
560 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
561 	int err;
562 
563 	/* this case is only from init_inode_metadata */
564 	if (ipage)
565 		return __f2fs_setxattr(inode, index, name, value,
566 						size, ipage, flags);
567 	f2fs_balance_fs(sbi, true);
568 
569 	f2fs_lock_op(sbi);
570 	/* protect xattr_ver */
571 	down_write(&F2FS_I(inode)->i_sem);
572 	err = __f2fs_setxattr(inode, index, name, value, size, ipage, flags);
573 	up_write(&F2FS_I(inode)->i_sem);
574 	f2fs_unlock_op(sbi);
575 
576 	f2fs_update_time(sbi, REQ_TIME);
577 	return err;
578 }
579