xref: /openbmc/linux/fs/f2fs/xattr.c (revision 8ff374b9) 
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_initxattrs(struct inode *inode, const struct xattr *xattr_array,
158 		void *page)
159 {
160 	const struct xattr *xattr;
161 	int err = 0;
162 
163 	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
164 		err = f2fs_setxattr(inode, F2FS_XATTR_INDEX_SECURITY,
165 				xattr->name, xattr->value,
166 				xattr->value_len, (struct page *)page);
167 		if (err < 0)
168 			break;
169 	}
170 	return err;
171 }
172 
173 int f2fs_init_security(struct inode *inode, struct inode *dir,
174 				const struct qstr *qstr, struct page *ipage)
175 {
176 	return security_inode_init_security(inode, dir, qstr,
177 				&f2fs_initxattrs, ipage);
178 }
179 #endif
180 
181 const struct xattr_handler f2fs_xattr_user_handler = {
182 	.prefix	= XATTR_USER_PREFIX,
183 	.flags	= F2FS_XATTR_INDEX_USER,
184 	.list	= f2fs_xattr_generic_list,
185 	.get	= f2fs_xattr_generic_get,
186 	.set	= f2fs_xattr_generic_set,
187 };
188 
189 const struct xattr_handler f2fs_xattr_trusted_handler = {
190 	.prefix	= XATTR_TRUSTED_PREFIX,
191 	.flags	= F2FS_XATTR_INDEX_TRUSTED,
192 	.list	= f2fs_xattr_generic_list,
193 	.get	= f2fs_xattr_generic_get,
194 	.set	= f2fs_xattr_generic_set,
195 };
196 
197 const struct xattr_handler f2fs_xattr_advise_handler = {
198 	.prefix = F2FS_SYSTEM_ADVISE_PREFIX,
199 	.flags	= F2FS_XATTR_INDEX_ADVISE,
200 	.list   = f2fs_xattr_advise_list,
201 	.get    = f2fs_xattr_advise_get,
202 	.set    = f2fs_xattr_advise_set,
203 };
204 
205 const struct xattr_handler f2fs_xattr_security_handler = {
206 	.prefix	= XATTR_SECURITY_PREFIX,
207 	.flags	= F2FS_XATTR_INDEX_SECURITY,
208 	.list	= f2fs_xattr_generic_list,
209 	.get	= f2fs_xattr_generic_get,
210 	.set	= f2fs_xattr_generic_set,
211 };
212 
213 static const struct xattr_handler *f2fs_xattr_handler_map[] = {
214 	[F2FS_XATTR_INDEX_USER] = &f2fs_xattr_user_handler,
215 #ifdef CONFIG_F2FS_FS_POSIX_ACL
216 	[F2FS_XATTR_INDEX_POSIX_ACL_ACCESS] = &f2fs_xattr_acl_access_handler,
217 	[F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT] = &f2fs_xattr_acl_default_handler,
218 #endif
219 	[F2FS_XATTR_INDEX_TRUSTED] = &f2fs_xattr_trusted_handler,
220 #ifdef CONFIG_F2FS_FS_SECURITY
221 	[F2FS_XATTR_INDEX_SECURITY] = &f2fs_xattr_security_handler,
222 #endif
223 	[F2FS_XATTR_INDEX_ADVISE] = &f2fs_xattr_advise_handler,
224 };
225 
226 const struct xattr_handler *f2fs_xattr_handlers[] = {
227 	&f2fs_xattr_user_handler,
228 #ifdef CONFIG_F2FS_FS_POSIX_ACL
229 	&f2fs_xattr_acl_access_handler,
230 	&f2fs_xattr_acl_default_handler,
231 #endif
232 	&f2fs_xattr_trusted_handler,
233 #ifdef CONFIG_F2FS_FS_SECURITY
234 	&f2fs_xattr_security_handler,
235 #endif
236 	&f2fs_xattr_advise_handler,
237 	NULL,
238 };
239 
240 static inline const struct xattr_handler *f2fs_xattr_handler(int name_index)
241 {
242 	const struct xattr_handler *handler = NULL;
243 
244 	if (name_index > 0 && name_index < ARRAY_SIZE(f2fs_xattr_handler_map))
245 		handler = f2fs_xattr_handler_map[name_index];
246 	return handler;
247 }
248 
249 static struct f2fs_xattr_entry *__find_xattr(void *base_addr, int name_index,
250 					size_t name_len, const char *name)
251 {
252 	struct f2fs_xattr_entry *entry;
253 
254 	list_for_each_xattr(entry, base_addr) {
255 		if (entry->e_name_index != name_index)
256 			continue;
257 		if (entry->e_name_len != name_len)
258 			continue;
259 		if (!memcmp(entry->e_name, name, name_len))
260 			break;
261 	}
262 	return entry;
263 }
264 
265 static void *read_all_xattrs(struct inode *inode, struct page *ipage)
266 {
267 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
268 	struct f2fs_xattr_header *header;
269 	size_t size = PAGE_SIZE, inline_size = 0;
270 	void *txattr_addr;
271 
272 	inline_size = inline_xattr_size(inode);
273 
274 	txattr_addr = kzalloc(inline_size + size, GFP_KERNEL);
275 	if (!txattr_addr)
276 		return NULL;
277 
278 	/* read from inline xattr */
279 	if (inline_size) {
280 		struct page *page = NULL;
281 		void *inline_addr;
282 
283 		if (ipage) {
284 			inline_addr = inline_xattr_addr(ipage);
285 		} else {
286 			page = get_node_page(sbi, inode->i_ino);
287 			if (IS_ERR(page))
288 				goto fail;
289 			inline_addr = inline_xattr_addr(page);
290 		}
291 		memcpy(txattr_addr, inline_addr, inline_size);
292 		f2fs_put_page(page, 1);
293 	}
294 
295 	/* read from xattr node block */
296 	if (F2FS_I(inode)->i_xattr_nid) {
297 		struct page *xpage;
298 		void *xattr_addr;
299 
300 		/* The inode already has an extended attribute block. */
301 		xpage = get_node_page(sbi, F2FS_I(inode)->i_xattr_nid);
302 		if (IS_ERR(xpage))
303 			goto fail;
304 
305 		xattr_addr = page_address(xpage);
306 		memcpy(txattr_addr + inline_size, xattr_addr, PAGE_SIZE);
307 		f2fs_put_page(xpage, 1);
308 	}
309 
310 	header = XATTR_HDR(txattr_addr);
311 
312 	/* never been allocated xattrs */
313 	if (le32_to_cpu(header->h_magic) != F2FS_XATTR_MAGIC) {
314 		header->h_magic = cpu_to_le32(F2FS_XATTR_MAGIC);
315 		header->h_refcount = cpu_to_le32(1);
316 	}
317 	return txattr_addr;
318 fail:
319 	kzfree(txattr_addr);
320 	return NULL;
321 }
322 
323 static inline int write_all_xattrs(struct inode *inode, __u32 hsize,
324 				void *txattr_addr, struct page *ipage)
325 {
326 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
327 	size_t inline_size = 0;
328 	void *xattr_addr;
329 	struct page *xpage;
330 	nid_t new_nid = 0;
331 	int err;
332 
333 	inline_size = inline_xattr_size(inode);
334 
335 	if (hsize > inline_size && !F2FS_I(inode)->i_xattr_nid)
336 		if (!alloc_nid(sbi, &new_nid))
337 			return -ENOSPC;
338 
339 	/* write to inline xattr */
340 	if (inline_size) {
341 		struct page *page = NULL;
342 		void *inline_addr;
343 
344 		if (ipage) {
345 			inline_addr = inline_xattr_addr(ipage);
346 		} else {
347 			page = get_node_page(sbi, inode->i_ino);
348 			if (IS_ERR(page)) {
349 				alloc_nid_failed(sbi, new_nid);
350 				return PTR_ERR(page);
351 			}
352 			inline_addr = inline_xattr_addr(page);
353 		}
354 		memcpy(inline_addr, txattr_addr, inline_size);
355 		f2fs_put_page(page, 1);
356 
357 		/* no need to use xattr node block */
358 		if (hsize <= inline_size) {
359 			err = truncate_xattr_node(inode, ipage);
360 			alloc_nid_failed(sbi, new_nid);
361 			return err;
362 		}
363 	}
364 
365 	/* write to xattr node block */
366 	if (F2FS_I(inode)->i_xattr_nid) {
367 		xpage = get_node_page(sbi, F2FS_I(inode)->i_xattr_nid);
368 		if (IS_ERR(xpage)) {
369 			alloc_nid_failed(sbi, new_nid);
370 			return PTR_ERR(xpage);
371 		}
372 		BUG_ON(new_nid);
373 	} else {
374 		struct dnode_of_data dn;
375 		set_new_dnode(&dn, inode, NULL, NULL, new_nid);
376 		xpage = new_node_page(&dn, XATTR_NODE_OFFSET, ipage);
377 		if (IS_ERR(xpage)) {
378 			alloc_nid_failed(sbi, new_nid);
379 			return PTR_ERR(xpage);
380 		}
381 		alloc_nid_done(sbi, new_nid);
382 	}
383 
384 	xattr_addr = page_address(xpage);
385 	memcpy(xattr_addr, txattr_addr + inline_size, PAGE_SIZE -
386 						sizeof(struct node_footer));
387 	set_page_dirty(xpage);
388 	f2fs_put_page(xpage, 1);
389 
390 	/* need to checkpoint during fsync */
391 	F2FS_I(inode)->xattr_ver = cur_cp_version(F2FS_CKPT(sbi));
392 	return 0;
393 }
394 
395 int f2fs_getxattr(struct inode *inode, int name_index, const char *name,
396 		void *buffer, size_t buffer_size)
397 {
398 	struct f2fs_xattr_entry *entry;
399 	void *base_addr;
400 	int error = 0;
401 	size_t value_len, name_len;
402 
403 	if (name == NULL)
404 		return -EINVAL;
405 	name_len = strlen(name);
406 
407 	base_addr = read_all_xattrs(inode, NULL);
408 	if (!base_addr)
409 		return -ENOMEM;
410 
411 	entry = __find_xattr(base_addr, name_index, name_len, name);
412 	if (IS_XATTR_LAST_ENTRY(entry)) {
413 		error = -ENODATA;
414 		goto cleanup;
415 	}
416 
417 	value_len = le16_to_cpu(entry->e_value_size);
418 
419 	if (buffer && value_len > buffer_size) {
420 		error = -ERANGE;
421 		goto cleanup;
422 	}
423 
424 	if (buffer) {
425 		char *pval = entry->e_name + entry->e_name_len;
426 		memcpy(buffer, pval, value_len);
427 	}
428 	error = value_len;
429 
430 cleanup:
431 	kzfree(base_addr);
432 	return error;
433 }
434 
435 ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
436 {
437 	struct inode *inode = dentry->d_inode;
438 	struct f2fs_xattr_entry *entry;
439 	void *base_addr;
440 	int error = 0;
441 	size_t rest = buffer_size;
442 
443 	base_addr = read_all_xattrs(inode, NULL);
444 	if (!base_addr)
445 		return -ENOMEM;
446 
447 	list_for_each_xattr(entry, base_addr) {
448 		const struct xattr_handler *handler =
449 			f2fs_xattr_handler(entry->e_name_index);
450 		size_t size;
451 
452 		if (!handler)
453 			continue;
454 
455 		size = handler->list(dentry, buffer, rest, entry->e_name,
456 				entry->e_name_len, handler->flags);
457 		if (buffer && size > rest) {
458 			error = -ERANGE;
459 			goto cleanup;
460 		}
461 
462 		if (buffer)
463 			buffer += size;
464 		rest -= size;
465 	}
466 	error = buffer_size - rest;
467 cleanup:
468 	kzfree(base_addr);
469 	return error;
470 }
471 
472 int f2fs_setxattr(struct inode *inode, int name_index, const char *name,
473 			const void *value, size_t value_len, struct page *ipage)
474 {
475 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
476 	struct f2fs_inode_info *fi = F2FS_I(inode);
477 	struct f2fs_xattr_entry *here, *last;
478 	void *base_addr;
479 	int found, newsize;
480 	size_t name_len;
481 	int ilock;
482 	__u32 new_hsize;
483 	int error = -ENOMEM;
484 
485 	if (name == NULL)
486 		return -EINVAL;
487 
488 	if (value == NULL)
489 		value_len = 0;
490 
491 	name_len = strlen(name);
492 
493 	if (name_len > F2FS_NAME_LEN || value_len > MAX_VALUE_LEN(inode))
494 		return -ERANGE;
495 
496 	f2fs_balance_fs(sbi);
497 
498 	ilock = mutex_lock_op(sbi);
499 
500 	base_addr = read_all_xattrs(inode, ipage);
501 	if (!base_addr)
502 		goto exit;
503 
504 	/* find entry with wanted name. */
505 	here = __find_xattr(base_addr, name_index, name_len, name);
506 
507 	found = IS_XATTR_LAST_ENTRY(here) ? 0 : 1;
508 	last = here;
509 
510 	while (!IS_XATTR_LAST_ENTRY(last))
511 		last = XATTR_NEXT_ENTRY(last);
512 
513 	newsize = XATTR_ALIGN(sizeof(struct f2fs_xattr_entry) +
514 			name_len + value_len);
515 
516 	/* 1. Check space */
517 	if (value) {
518 		int free;
519 		/*
520 		 * If value is NULL, it is remove operation.
521 		 * In case of update operation, we caculate free.
522 		 */
523 		free = MIN_OFFSET(inode) - ((char *)last - (char *)base_addr);
524 		if (found)
525 			free = free - ENTRY_SIZE(here);
526 
527 		if (free < newsize) {
528 			error = -ENOSPC;
529 			goto exit;
530 		}
531 	}
532 
533 	/* 2. Remove old entry */
534 	if (found) {
535 		/*
536 		 * If entry is found, remove old entry.
537 		 * If not found, remove operation is not needed.
538 		 */
539 		struct f2fs_xattr_entry *next = XATTR_NEXT_ENTRY(here);
540 		int oldsize = ENTRY_SIZE(here);
541 
542 		memmove(here, next, (char *)last - (char *)next);
543 		last = (struct f2fs_xattr_entry *)((char *)last - oldsize);
544 		memset(last, 0, oldsize);
545 	}
546 
547 	new_hsize = (char *)last - (char *)base_addr;
548 
549 	/* 3. Write new entry */
550 	if (value) {
551 		char *pval;
552 		/*
553 		 * Before we come here, old entry is removed.
554 		 * We just write new entry.
555 		 */
556 		memset(last, 0, newsize);
557 		last->e_name_index = name_index;
558 		last->e_name_len = name_len;
559 		memcpy(last->e_name, name, name_len);
560 		pval = last->e_name + name_len;
561 		memcpy(pval, value, value_len);
562 		last->e_value_size = cpu_to_le16(value_len);
563 		new_hsize += newsize;
564 	}
565 
566 	error = write_all_xattrs(inode, new_hsize, base_addr, ipage);
567 	if (error)
568 		goto exit;
569 
570 	if (is_inode_flag_set(fi, FI_ACL_MODE)) {
571 		inode->i_mode = fi->i_acl_mode;
572 		inode->i_ctime = CURRENT_TIME;
573 		clear_inode_flag(fi, FI_ACL_MODE);
574 	}
575 
576 	if (ipage)
577 		update_inode(inode, ipage);
578 	else
579 		update_inode_page(inode);
580 exit:
581 	mutex_unlock_op(sbi, ilock);
582 	kzfree(base_addr);
583 	return error;
584 }
585