xref: /openbmc/linux/fs/f2fs/xattr.c (revision 77d84ff8) 
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 "f2fs.h"
25 #include "xattr.h"
26 
27 static size_t f2fs_xattr_generic_list(struct dentry *dentry, char *list,
28 		size_t list_size, const char *name, size_t name_len, int type)
29 {
30 	struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
31 	int total_len, prefix_len = 0;
32 	const char *prefix = NULL;
33 
34 	switch (type) {
35 	case F2FS_XATTR_INDEX_USER:
36 		if (!test_opt(sbi, XATTR_USER))
37 			return -EOPNOTSUPP;
38 		prefix = XATTR_USER_PREFIX;
39 		prefix_len = XATTR_USER_PREFIX_LEN;
40 		break;
41 	case F2FS_XATTR_INDEX_TRUSTED:
42 		if (!capable(CAP_SYS_ADMIN))
43 			return -EPERM;
44 		prefix = XATTR_TRUSTED_PREFIX;
45 		prefix_len = XATTR_TRUSTED_PREFIX_LEN;
46 		break;
47 	case F2FS_XATTR_INDEX_SECURITY:
48 		prefix = XATTR_SECURITY_PREFIX;
49 		prefix_len = XATTR_SECURITY_PREFIX_LEN;
50 		break;
51 	default:
52 		return -EINVAL;
53 	}
54 
55 	total_len = prefix_len + name_len + 1;
56 	if (list && total_len <= list_size) {
57 		memcpy(list, prefix, prefix_len);
58 		memcpy(list + prefix_len, name, name_len);
59 		list[prefix_len + name_len] = '\0';
60 	}
61 	return total_len;
62 }
63 
64 static int f2fs_xattr_generic_get(struct dentry *dentry, const char *name,
65 		void *buffer, size_t size, int type)
66 {
67 	struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
68 
69 	switch (type) {
70 	case F2FS_XATTR_INDEX_USER:
71 		if (!test_opt(sbi, XATTR_USER))
72 			return -EOPNOTSUPP;
73 		break;
74 	case F2FS_XATTR_INDEX_TRUSTED:
75 		if (!capable(CAP_SYS_ADMIN))
76 			return -EPERM;
77 		break;
78 	case F2FS_XATTR_INDEX_SECURITY:
79 		break;
80 	default:
81 		return -EINVAL;
82 	}
83 	if (strcmp(name, "") == 0)
84 		return -EINVAL;
85 	return f2fs_getxattr(dentry->d_inode, type, name, buffer, size);
86 }
87 
88 static int f2fs_xattr_generic_set(struct dentry *dentry, const char *name,
89 		const void *value, size_t size, int flags, int type)
90 {
91 	struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
92 
93 	switch (type) {
94 	case F2FS_XATTR_INDEX_USER:
95 		if (!test_opt(sbi, XATTR_USER))
96 			return -EOPNOTSUPP;
97 		break;
98 	case F2FS_XATTR_INDEX_TRUSTED:
99 		if (!capable(CAP_SYS_ADMIN))
100 			return -EPERM;
101 		break;
102 	case F2FS_XATTR_INDEX_SECURITY:
103 		break;
104 	default:
105 		return -EINVAL;
106 	}
107 	if (strcmp(name, "") == 0)
108 		return -EINVAL;
109 
110 	return f2fs_setxattr(dentry->d_inode, type, name, value, size, NULL);
111 }
112 
113 static size_t f2fs_xattr_advise_list(struct dentry *dentry, char *list,
114 		size_t list_size, const char *name, size_t name_len, int type)
115 {
116 	const char *xname = F2FS_SYSTEM_ADVISE_PREFIX;
117 	size_t size;
118 
119 	if (type != F2FS_XATTR_INDEX_ADVISE)
120 		return 0;
121 
122 	size = strlen(xname) + 1;
123 	if (list && size <= list_size)
124 		memcpy(list, xname, size);
125 	return size;
126 }
127 
128 static int f2fs_xattr_advise_get(struct dentry *dentry, const char *name,
129 		void *buffer, size_t size, int type)
130 {
131 	struct inode *inode = dentry->d_inode;
132 
133 	if (strcmp(name, "") != 0)
134 		return -EINVAL;
135 
136 	*((char *)buffer) = F2FS_I(inode)->i_advise;
137 	return sizeof(char);
138 }
139 
140 static int f2fs_xattr_advise_set(struct dentry *dentry, const char *name,
141 		const void *value, size_t size, int flags, int type)
142 {
143 	struct inode *inode = dentry->d_inode;
144 
145 	if (strcmp(name, "") != 0)
146 		return -EINVAL;
147 	if (!inode_owner_or_capable(inode))
148 		return -EPERM;
149 	if (value == NULL)
150 		return -EINVAL;
151 
152 	F2FS_I(inode)->i_advise |= *(char *)value;
153 	return 0;
154 }
155 
156 #ifdef CONFIG_F2FS_FS_SECURITY
157 static int __f2fs_setxattr(struct inode *inode, int name_index,
158 			const char *name, const void *value, size_t value_len,
159 			struct page *ipage);
160 static int f2fs_initxattrs(struct inode *inode, const struct xattr *xattr_array,
161 		void *page)
162 {
163 	const struct xattr *xattr;
164 	int err = 0;
165 
166 	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
167 		err = __f2fs_setxattr(inode, F2FS_XATTR_INDEX_SECURITY,
168 				xattr->name, xattr->value,
169 				xattr->value_len, (struct page *)page);
170 		if (err < 0)
171 			break;
172 	}
173 	return err;
174 }
175 
176 int f2fs_init_security(struct inode *inode, struct inode *dir,
177 				const struct qstr *qstr, struct page *ipage)
178 {
179 	return security_inode_init_security(inode, dir, qstr,
180 				&f2fs_initxattrs, ipage);
181 }
182 #endif
183 
184 const struct xattr_handler f2fs_xattr_user_handler = {
185 	.prefix	= XATTR_USER_PREFIX,
186 	.flags	= F2FS_XATTR_INDEX_USER,
187 	.list	= f2fs_xattr_generic_list,
188 	.get	= f2fs_xattr_generic_get,
189 	.set	= f2fs_xattr_generic_set,
190 };
191 
192 const struct xattr_handler f2fs_xattr_trusted_handler = {
193 	.prefix	= XATTR_TRUSTED_PREFIX,
194 	.flags	= F2FS_XATTR_INDEX_TRUSTED,
195 	.list	= f2fs_xattr_generic_list,
196 	.get	= f2fs_xattr_generic_get,
197 	.set	= f2fs_xattr_generic_set,
198 };
199 
200 const struct xattr_handler f2fs_xattr_advise_handler = {
201 	.prefix = F2FS_SYSTEM_ADVISE_PREFIX,
202 	.flags	= F2FS_XATTR_INDEX_ADVISE,
203 	.list   = f2fs_xattr_advise_list,
204 	.get    = f2fs_xattr_advise_get,
205 	.set    = f2fs_xattr_advise_set,
206 };
207 
208 const struct xattr_handler f2fs_xattr_security_handler = {
209 	.prefix	= XATTR_SECURITY_PREFIX,
210 	.flags	= F2FS_XATTR_INDEX_SECURITY,
211 	.list	= f2fs_xattr_generic_list,
212 	.get	= f2fs_xattr_generic_get,
213 	.set	= f2fs_xattr_generic_set,
214 };
215 
216 static const struct xattr_handler *f2fs_xattr_handler_map[] = {
217 	[F2FS_XATTR_INDEX_USER] = &f2fs_xattr_user_handler,
218 #ifdef CONFIG_F2FS_FS_POSIX_ACL
219 	[F2FS_XATTR_INDEX_POSIX_ACL_ACCESS] = &f2fs_xattr_acl_access_handler,
220 	[F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT] = &f2fs_xattr_acl_default_handler,
221 #endif
222 	[F2FS_XATTR_INDEX_TRUSTED] = &f2fs_xattr_trusted_handler,
223 #ifdef CONFIG_F2FS_FS_SECURITY
224 	[F2FS_XATTR_INDEX_SECURITY] = &f2fs_xattr_security_handler,
225 #endif
226 	[F2FS_XATTR_INDEX_ADVISE] = &f2fs_xattr_advise_handler,
227 };
228 
229 const struct xattr_handler *f2fs_xattr_handlers[] = {
230 	&f2fs_xattr_user_handler,
231 #ifdef CONFIG_F2FS_FS_POSIX_ACL
232 	&f2fs_xattr_acl_access_handler,
233 	&f2fs_xattr_acl_default_handler,
234 #endif
235 	&f2fs_xattr_trusted_handler,
236 #ifdef CONFIG_F2FS_FS_SECURITY
237 	&f2fs_xattr_security_handler,
238 #endif
239 	&f2fs_xattr_advise_handler,
240 	NULL,
241 };
242 
243 static inline const struct xattr_handler *f2fs_xattr_handler(int name_index)
244 {
245 	const struct xattr_handler *handler = NULL;
246 
247 	if (name_index > 0 && name_index < ARRAY_SIZE(f2fs_xattr_handler_map))
248 		handler = f2fs_xattr_handler_map[name_index];
249 	return handler;
250 }
251 
252 static struct f2fs_xattr_entry *__find_xattr(void *base_addr, int name_index,
253 					size_t name_len, const char *name)
254 {
255 	struct f2fs_xattr_entry *entry;
256 
257 	list_for_each_xattr(entry, base_addr) {
258 		if (entry->e_name_index != name_index)
259 			continue;
260 		if (entry->e_name_len != name_len)
261 			continue;
262 		if (!memcmp(entry->e_name, name, name_len))
263 			break;
264 	}
265 	return entry;
266 }
267 
268 static void *read_all_xattrs(struct inode *inode, struct page *ipage)
269 {
270 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
271 	struct f2fs_xattr_header *header;
272 	size_t size = PAGE_SIZE, inline_size = 0;
273 	void *txattr_addr;
274 
275 	inline_size = inline_xattr_size(inode);
276 
277 	txattr_addr = kzalloc(inline_size + size, GFP_KERNEL);
278 	if (!txattr_addr)
279 		return NULL;
280 
281 	/* read from inline xattr */
282 	if (inline_size) {
283 		struct page *page = NULL;
284 		void *inline_addr;
285 
286 		if (ipage) {
287 			inline_addr = inline_xattr_addr(ipage);
288 		} else {
289 			page = get_node_page(sbi, inode->i_ino);
290 			if (IS_ERR(page))
291 				goto fail;
292 			inline_addr = inline_xattr_addr(page);
293 		}
294 		memcpy(txattr_addr, inline_addr, inline_size);
295 		f2fs_put_page(page, 1);
296 	}
297 
298 	/* read from xattr node block */
299 	if (F2FS_I(inode)->i_xattr_nid) {
300 		struct page *xpage;
301 		void *xattr_addr;
302 
303 		/* The inode already has an extended attribute block. */
304 		xpage = get_node_page(sbi, F2FS_I(inode)->i_xattr_nid);
305 		if (IS_ERR(xpage))
306 			goto fail;
307 
308 		xattr_addr = page_address(xpage);
309 		memcpy(txattr_addr + inline_size, xattr_addr, PAGE_SIZE);
310 		f2fs_put_page(xpage, 1);
311 	}
312 
313 	header = XATTR_HDR(txattr_addr);
314 
315 	/* never been allocated xattrs */
316 	if (le32_to_cpu(header->h_magic) != F2FS_XATTR_MAGIC) {
317 		header->h_magic = cpu_to_le32(F2FS_XATTR_MAGIC);
318 		header->h_refcount = cpu_to_le32(1);
319 	}
320 	return txattr_addr;
321 fail:
322 	kzfree(txattr_addr);
323 	return NULL;
324 }
325 
326 static inline int write_all_xattrs(struct inode *inode, __u32 hsize,
327 				void *txattr_addr, struct page *ipage)
328 {
329 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
330 	size_t inline_size = 0;
331 	void *xattr_addr;
332 	struct page *xpage;
333 	nid_t new_nid = 0;
334 	int err;
335 
336 	inline_size = inline_xattr_size(inode);
337 
338 	if (hsize > inline_size && !F2FS_I(inode)->i_xattr_nid)
339 		if (!alloc_nid(sbi, &new_nid))
340 			return -ENOSPC;
341 
342 	/* write to inline xattr */
343 	if (inline_size) {
344 		struct page *page = NULL;
345 		void *inline_addr;
346 
347 		if (ipage) {
348 			inline_addr = inline_xattr_addr(ipage);
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 		}
357 		memcpy(inline_addr, txattr_addr, inline_size);
358 		f2fs_put_page(page, 1);
359 
360 		/* no need to use xattr node block */
361 		if (hsize <= inline_size) {
362 			err = truncate_xattr_node(inode, ipage);
363 			alloc_nid_failed(sbi, new_nid);
364 			return err;
365 		}
366 	}
367 
368 	/* write to xattr node block */
369 	if (F2FS_I(inode)->i_xattr_nid) {
370 		xpage = get_node_page(sbi, F2FS_I(inode)->i_xattr_nid);
371 		if (IS_ERR(xpage)) {
372 			alloc_nid_failed(sbi, new_nid);
373 			return PTR_ERR(xpage);
374 		}
375 		f2fs_bug_on(new_nid);
376 	} else {
377 		struct dnode_of_data dn;
378 		set_new_dnode(&dn, inode, NULL, NULL, new_nid);
379 		xpage = new_node_page(&dn, XATTR_NODE_OFFSET, ipage);
380 		if (IS_ERR(xpage)) {
381 			alloc_nid_failed(sbi, new_nid);
382 			return PTR_ERR(xpage);
383 		}
384 		alloc_nid_done(sbi, new_nid);
385 	}
386 
387 	xattr_addr = page_address(xpage);
388 	memcpy(xattr_addr, txattr_addr + inline_size, PAGE_SIZE -
389 						sizeof(struct node_footer));
390 	set_page_dirty(xpage);
391 	f2fs_put_page(xpage, 1);
392 
393 	/* need to checkpoint during fsync */
394 	F2FS_I(inode)->xattr_ver = cur_cp_version(F2FS_CKPT(sbi));
395 	return 0;
396 }
397 
398 int f2fs_getxattr(struct inode *inode, int name_index, const char *name,
399 		void *buffer, size_t buffer_size)
400 {
401 	struct f2fs_xattr_entry *entry;
402 	void *base_addr;
403 	int error = 0;
404 	size_t value_len, name_len;
405 
406 	if (name == NULL)
407 		return -EINVAL;
408 	name_len = strlen(name);
409 
410 	base_addr = read_all_xattrs(inode, NULL);
411 	if (!base_addr)
412 		return -ENOMEM;
413 
414 	entry = __find_xattr(base_addr, name_index, name_len, name);
415 	if (IS_XATTR_LAST_ENTRY(entry)) {
416 		error = -ENODATA;
417 		goto cleanup;
418 	}
419 
420 	value_len = le16_to_cpu(entry->e_value_size);
421 
422 	if (buffer && value_len > buffer_size) {
423 		error = -ERANGE;
424 		goto cleanup;
425 	}
426 
427 	if (buffer) {
428 		char *pval = entry->e_name + entry->e_name_len;
429 		memcpy(buffer, pval, value_len);
430 	}
431 	error = value_len;
432 
433 cleanup:
434 	kzfree(base_addr);
435 	return error;
436 }
437 
438 ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
439 {
440 	struct inode *inode = dentry->d_inode;
441 	struct f2fs_xattr_entry *entry;
442 	void *base_addr;
443 	int error = 0;
444 	size_t rest = buffer_size;
445 
446 	base_addr = read_all_xattrs(inode, NULL);
447 	if (!base_addr)
448 		return -ENOMEM;
449 
450 	list_for_each_xattr(entry, base_addr) {
451 		const struct xattr_handler *handler =
452 			f2fs_xattr_handler(entry->e_name_index);
453 		size_t size;
454 
455 		if (!handler)
456 			continue;
457 
458 		size = handler->list(dentry, buffer, rest, entry->e_name,
459 				entry->e_name_len, handler->flags);
460 		if (buffer && size > rest) {
461 			error = -ERANGE;
462 			goto cleanup;
463 		}
464 
465 		if (buffer)
466 			buffer += size;
467 		rest -= size;
468 	}
469 	error = buffer_size - rest;
470 cleanup:
471 	kzfree(base_addr);
472 	return error;
473 }
474 
475 static int __f2fs_setxattr(struct inode *inode, int name_index,
476 			const char *name, const void *value, size_t value_len,
477 			struct page *ipage)
478 {
479 	struct f2fs_inode_info *fi = F2FS_I(inode);
480 	struct f2fs_xattr_entry *here, *last;
481 	void *base_addr;
482 	int found, newsize;
483 	size_t name_len;
484 	__u32 new_hsize;
485 	int error = -ENOMEM;
486 
487 	if (name == NULL)
488 		return -EINVAL;
489 
490 	if (value == NULL)
491 		value_len = 0;
492 
493 	name_len = strlen(name);
494 
495 	if (name_len > F2FS_NAME_LEN || value_len > MAX_VALUE_LEN(inode))
496 		return -ERANGE;
497 
498 	base_addr = read_all_xattrs(inode, ipage);
499 	if (!base_addr)
500 		goto exit;
501 
502 	/* find entry with wanted name. */
503 	here = __find_xattr(base_addr, name_index, name_len, name);
504 
505 	found = IS_XATTR_LAST_ENTRY(here) ? 0 : 1;
506 	last = here;
507 
508 	while (!IS_XATTR_LAST_ENTRY(last))
509 		last = XATTR_NEXT_ENTRY(last);
510 
511 	newsize = XATTR_ALIGN(sizeof(struct f2fs_xattr_entry) +
512 			name_len + value_len);
513 
514 	/* 1. Check space */
515 	if (value) {
516 		int free;
517 		/*
518 		 * If value is NULL, it is remove operation.
519 		 * In case of update operation, we caculate free.
520 		 */
521 		free = MIN_OFFSET(inode) - ((char *)last - (char *)base_addr);
522 		if (found)
523 			free = free + ENTRY_SIZE(here);
524 
525 		if (free < newsize) {
526 			error = -ENOSPC;
527 			goto exit;
528 		}
529 	}
530 
531 	/* 2. Remove old entry */
532 	if (found) {
533 		/*
534 		 * If entry is found, remove old entry.
535 		 * If not found, remove operation is not needed.
536 		 */
537 		struct f2fs_xattr_entry *next = XATTR_NEXT_ENTRY(here);
538 		int oldsize = ENTRY_SIZE(here);
539 
540 		memmove(here, next, (char *)last - (char *)next);
541 		last = (struct f2fs_xattr_entry *)((char *)last - oldsize);
542 		memset(last, 0, oldsize);
543 	}
544 
545 	new_hsize = (char *)last - (char *)base_addr;
546 
547 	/* 3. Write new entry */
548 	if (value) {
549 		char *pval;
550 		/*
551 		 * Before we come here, old entry is removed.
552 		 * We just write new entry.
553 		 */
554 		memset(last, 0, newsize);
555 		last->e_name_index = name_index;
556 		last->e_name_len = name_len;
557 		memcpy(last->e_name, name, name_len);
558 		pval = last->e_name + name_len;
559 		memcpy(pval, value, value_len);
560 		last->e_value_size = cpu_to_le16(value_len);
561 		new_hsize += newsize;
562 	}
563 
564 	error = write_all_xattrs(inode, new_hsize, base_addr, ipage);
565 	if (error)
566 		goto exit;
567 
568 	if (is_inode_flag_set(fi, FI_ACL_MODE)) {
569 		inode->i_mode = fi->i_acl_mode;
570 		inode->i_ctime = CURRENT_TIME;
571 		clear_inode_flag(fi, FI_ACL_MODE);
572 	}
573 
574 	if (ipage)
575 		update_inode(inode, ipage);
576 	else
577 		update_inode_page(inode);
578 exit:
579 	kzfree(base_addr);
580 	return error;
581 }
582 
583 int f2fs_setxattr(struct inode *inode, int name_index, const char *name,
584 			const void *value, size_t value_len, struct page *ipage)
585 {
586 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
587 	int err;
588 
589 	f2fs_balance_fs(sbi);
590 
591 	f2fs_lock_op(sbi);
592 	err = __f2fs_setxattr(inode, name_index, name, value, value_len, ipage);
593 	f2fs_unlock_op(sbi);
594 
595 	return err;
596 }
597