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f2fs: enhance lookup xattr
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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, true);
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 struct f2fs_xattr_entry *__find_inline_xattr(void *base_addr,
221 void **last_addr, int index,
222 size_t len, const char *name)
223 {
224 struct f2fs_xattr_entry *entry;
225 unsigned int inline_size = F2FS_INLINE_XATTR_ADDRS << 2;
226
227 list_for_each_xattr(entry, base_addr) {
228 if ((void *)entry + sizeof(__u32) > base_addr + inline_size ||
229 (void *)XATTR_NEXT_ENTRY(entry) + sizeof(__u32) >
230 base_addr + inline_size) {
231 *last_addr = entry;
232 return NULL;
233 }
234 if (entry->e_name_index != index)
235 continue;
236 if (entry->e_name_len != len)
237 continue;
238 if (!memcmp(entry->e_name, name, len))
239 break;
240 }
241 return entry;
242 }
243
244 static int lookup_all_xattrs(struct inode *inode, struct page *ipage,
245 unsigned int index, unsigned int len,
246 const char *name, struct f2fs_xattr_entry **xe,
247 void **base_addr)
248 {
249 struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
250 void *cur_addr, *txattr_addr, *last_addr = NULL;
251 nid_t xnid = F2FS_I(inode)->i_xattr_nid;
252 unsigned int size = xnid ? VALID_XATTR_BLOCK_SIZE : 0;
253 unsigned int inline_size = 0;
254 int err = 0;
255
256 inline_size = inline_xattr_size(inode);
257
258 if (!size && !inline_size)
259 return -ENODATA;
260
261 txattr_addr = kzalloc(inline_size + size + sizeof(__u32),
262 GFP_F2FS_ZERO);
263 if (!txattr_addr)
264 return -ENOMEM;
265
266 /* read from inline xattr */
267 if (inline_size) {
268 struct page *page = NULL;
269 void *inline_addr;
270
271 if (ipage) {
272 inline_addr = inline_xattr_addr(ipage);
273 } else {
274 page = get_node_page(sbi, inode->i_ino);
275 if (IS_ERR(page)) {
276 err = PTR_ERR(page);
277 goto out;
278 }
279 inline_addr = inline_xattr_addr(page);
280 }
281 memcpy(txattr_addr, inline_addr, inline_size);
282 f2fs_put_page(page, 1);
283
284 *xe = __find_inline_xattr(txattr_addr, &last_addr,
285 index, len, name);
286 if (*xe)
287 goto check;
288 }
289
290 /* read from xattr node block */
291 if (xnid) {
292 struct page *xpage;
293 void *xattr_addr;
294
295 /* The inode already has an extended attribute block. */
296 xpage = get_node_page(sbi, xnid);
297 if (IS_ERR(xpage)) {
298 err = PTR_ERR(xpage);
299 goto out;
300 }
301
302 xattr_addr = page_address(xpage);
303 memcpy(txattr_addr + inline_size, xattr_addr, size);
304 f2fs_put_page(xpage, 1);
305 }
306
307 if (last_addr)
308 cur_addr = XATTR_HDR(last_addr) - 1;
309 else
310 cur_addr = txattr_addr;
311
312 *xe = __find_xattr(cur_addr, index, len, name);
313 check:
314 if (IS_XATTR_LAST_ENTRY(*xe)) {
315 err = -ENODATA;
316 goto out;
317 }
318
319 *base_addr = txattr_addr;
320 return 0;
321 out:
322 kzfree(txattr_addr);
323 return err;
324 }
325
326 static int read_all_xattrs(struct inode *inode, struct page *ipage,
327 void **base_addr)
328 {
329 struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
330 struct f2fs_xattr_header *header;
331 size_t size = PAGE_SIZE, inline_size = 0;
332 void *txattr_addr;
333 int err;
334
335 inline_size = inline_xattr_size(inode);
336
337 txattr_addr = kzalloc(inline_size + size, GFP_F2FS_ZERO);
338 if (!txattr_addr)
339 return -ENOMEM;
340
341 /* read from 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 } else {
349 page = get_node_page(sbi, inode->i_ino);
350 if (IS_ERR(page)) {
351 err = PTR_ERR(page);
352 goto fail;
353 }
354 inline_addr = inline_xattr_addr(page);
355 }
356 memcpy(txattr_addr, inline_addr, inline_size);
357 f2fs_put_page(page, 1);
358 }
359
360 /* read from xattr node block */
361 if (F2FS_I(inode)->i_xattr_nid) {
362 struct page *xpage;
363 void *xattr_addr;
364
365 /* The inode already has an extended attribute block. */
366 xpage = get_node_page(sbi, F2FS_I(inode)->i_xattr_nid);
367 if (IS_ERR(xpage)) {
368 err = PTR_ERR(xpage);
369 goto fail;
370 }
371
372 xattr_addr = page_address(xpage);
373 memcpy(txattr_addr + inline_size, xattr_addr, PAGE_SIZE);
374 f2fs_put_page(xpage, 1);
375 }
376
377 header = XATTR_HDR(txattr_addr);
378
379 /* never been allocated xattrs */
380 if (le32_to_cpu(header->h_magic) != F2FS_XATTR_MAGIC) {
381 header->h_magic = cpu_to_le32(F2FS_XATTR_MAGIC);
382 header->h_refcount = cpu_to_le32(1);
383 }
384 *base_addr = txattr_addr;
385 return 0;
386 fail:
387 kzfree(txattr_addr);
388 return err;
389 }
390
391 static inline int write_all_xattrs(struct inode *inode, __u32 hsize,
392 void *txattr_addr, struct page *ipage)
393 {
394 struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
395 size_t inline_size = 0;
396 void *xattr_addr;
397 struct page *xpage;
398 nid_t new_nid = 0;
399 int err;
400
401 inline_size = inline_xattr_size(inode);
402
403 if (hsize > inline_size && !F2FS_I(inode)->i_xattr_nid)
404 if (!alloc_nid(sbi, &new_nid))
405 return -ENOSPC;
406
407 /* write to inline xattr */
408 if (inline_size) {
409 struct page *page = NULL;
410 void *inline_addr;
411
412 if (ipage) {
413 inline_addr = inline_xattr_addr(ipage);
414 f2fs_wait_on_page_writeback(ipage, NODE, true);
415 set_page_dirty(ipage);
416 } else {
417 page = get_node_page(sbi, inode->i_ino);
418 if (IS_ERR(page)) {
419 alloc_nid_failed(sbi, new_nid);
420 return PTR_ERR(page);
421 }
422 inline_addr = inline_xattr_addr(page);
423 f2fs_wait_on_page_writeback(page, NODE, true);
424 }
425 memcpy(inline_addr, txattr_addr, inline_size);
426 f2fs_put_page(page, 1);
427
428 /* no need to use xattr node block */
429 if (hsize <= inline_size) {
430 err = truncate_xattr_node(inode, ipage);
431 alloc_nid_failed(sbi, new_nid);
432 return err;
433 }
434 }
435
436 /* write to xattr node block */
437 if (F2FS_I(inode)->i_xattr_nid) {
438 xpage = get_node_page(sbi, F2FS_I(inode)->i_xattr_nid);
439 if (IS_ERR(xpage)) {
440 alloc_nid_failed(sbi, new_nid);
441 return PTR_ERR(xpage);
442 }
443 f2fs_bug_on(sbi, new_nid);
444 f2fs_wait_on_page_writeback(xpage, NODE, true);
445 } else {
446 struct dnode_of_data dn;
447 set_new_dnode(&dn, inode, NULL, NULL, new_nid);
448 xpage = new_node_page(&dn, XATTR_NODE_OFFSET, ipage);
449 if (IS_ERR(xpage)) {
450 alloc_nid_failed(sbi, new_nid);
451 return PTR_ERR(xpage);
452 }
453 alloc_nid_done(sbi, new_nid);
454 }
455
456 xattr_addr = page_address(xpage);
457 memcpy(xattr_addr, txattr_addr + inline_size, MAX_XATTR_BLOCK_SIZE);
458 set_page_dirty(xpage);
459 f2fs_put_page(xpage, 1);
460
461 /* need to checkpoint during fsync */
462 F2FS_I(inode)->xattr_ver = cur_cp_version(F2FS_CKPT(sbi));
463 return 0;
464 }
465
466 int f2fs_getxattr(struct inode *inode, int index, const char *name,
467 void *buffer, size_t buffer_size, struct page *ipage)
468 {
469 struct f2fs_xattr_entry *entry = NULL;
470 int error = 0;
471 unsigned int size, len;
472 char *pval;
473 void *base_addr = NULL;
474
475 if (name == NULL)
476 return -EINVAL;
477
478 len = strlen(name);
479 if (len > F2FS_NAME_LEN)
480 return -ERANGE;
481
482 error = lookup_all_xattrs(inode, ipage, index, len, name,
483 &entry, &base_addr);
484 if (error)
485 return error;
486
487 size = le16_to_cpu(entry->e_value_size);
488
489 if (buffer && size > buffer_size) {
490 error = -ERANGE;
491 goto out;
492 }
493
494 pval = entry->e_name + entry->e_name_len;
495
496 if (buffer) {
497 char *pval = entry->e_name + entry->e_name_len;
498 memcpy(buffer, pval, size);
499 }
500 error = size;
501 out:
502 kzfree(base_addr);
503 return error;
504 }
505
506 ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
507 {
508 struct inode *inode = d_inode(dentry);
509 struct f2fs_xattr_entry *entry;
510 void *base_addr;
511 int error = 0;
512 size_t rest = buffer_size;
513
514 error = read_all_xattrs(inode, NULL, &base_addr);
515 if (error)
516 return error;
517
518 list_for_each_xattr(entry, base_addr) {
519 const struct xattr_handler *handler =
520 f2fs_xattr_handler(entry->e_name_index);
521 const char *prefix;
522 size_t prefix_len;
523 size_t size;
524
525 if (!handler || (handler->list && !handler->list(dentry)))
526 continue;
527
528 prefix = handler->prefix ?: handler->name;
529 prefix_len = strlen(prefix);
530 size = prefix_len + entry->e_name_len + 1;
531 if (buffer) {
532 if (size > rest) {
533 error = -ERANGE;
534 goto cleanup;
535 }
536 memcpy(buffer, prefix, prefix_len);
537 buffer += prefix_len;
538 memcpy(buffer, entry->e_name, entry->e_name_len);
539 buffer += entry->e_name_len;
540 *buffer++ = 0;
541 }
542 rest -= size;
543 }
544 error = buffer_size - rest;
545 cleanup:
546 kzfree(base_addr);
547 return error;
548 }
549
550 static int __f2fs_setxattr(struct inode *inode, int index,
551 const char *name, const void *value, size_t size,
552 struct page *ipage, int flags)
553 {
554 struct f2fs_xattr_entry *here, *last;
555 void *base_addr;
556 int found, newsize;
557 size_t len;
558 __u32 new_hsize;
559 int error = 0;
560
561 if (name == NULL)
562 return -EINVAL;
563
564 if (value == NULL)
565 size = 0;
566
567 len = strlen(name);
568
569 if (len > F2FS_NAME_LEN)
570 return -ERANGE;
571
572 if (size > MAX_VALUE_LEN(inode))
573 return -E2BIG;
574
575 error = read_all_xattrs(inode, ipage, &base_addr);
576 if (error)
577 return error;
578
579 /* find entry with wanted name. */
580 here = __find_xattr(base_addr, index, len, name);
581
582 found = IS_XATTR_LAST_ENTRY(here) ? 0 : 1;
583
584 if ((flags & XATTR_REPLACE) && !found) {
585 error = -ENODATA;
586 goto exit;
587 } else if ((flags & XATTR_CREATE) && found) {
588 error = -EEXIST;
589 goto exit;
590 }
591
592 last = here;
593 while (!IS_XATTR_LAST_ENTRY(last))
594 last = XATTR_NEXT_ENTRY(last);
595
596 newsize = XATTR_ALIGN(sizeof(struct f2fs_xattr_entry) + len + size);
597
598 /* 1. Check space */
599 if (value) {
600 int free;
601 /*
602 * If value is NULL, it is remove operation.
603 * In case of update operation, we calculate free.
604 */
605 free = MIN_OFFSET(inode) - ((char *)last - (char *)base_addr);
606 if (found)
607 free = free + ENTRY_SIZE(here);
608
609 if (unlikely(free < newsize)) {
610 error = -E2BIG;
611 goto exit;
612 }
613 }
614
615 /* 2. Remove old entry */
616 if (found) {
617 /*
618 * If entry is found, remove old entry.
619 * If not found, remove operation is not needed.
620 */
621 struct f2fs_xattr_entry *next = XATTR_NEXT_ENTRY(here);
622 int oldsize = ENTRY_SIZE(here);
623
624 memmove(here, next, (char *)last - (char *)next);
625 last = (struct f2fs_xattr_entry *)((char *)last - oldsize);
626 memset(last, 0, oldsize);
627 }
628
629 new_hsize = (char *)last - (char *)base_addr;
630
631 /* 3. Write new entry */
632 if (value) {
633 char *pval;
634 /*
635 * Before we come here, old entry is removed.
636 * We just write new entry.
637 */
638 last->e_name_index = index;
639 last->e_name_len = len;
640 memcpy(last->e_name, name, len);
641 pval = last->e_name + len;
642 memcpy(pval, value, size);
643 last->e_value_size = cpu_to_le16(size);
644 new_hsize += newsize;
645 }
646
647 error = write_all_xattrs(inode, new_hsize, base_addr, ipage);
648 if (error)
649 goto exit;
650
651 if (is_inode_flag_set(inode, FI_ACL_MODE)) {
652 inode->i_mode = F2FS_I(inode)->i_acl_mode;
653 inode->i_ctime = current_time(inode);
654 clear_inode_flag(inode, FI_ACL_MODE);
655 }
656 if (index == F2FS_XATTR_INDEX_ENCRYPTION &&
657 !strcmp(name, F2FS_XATTR_NAME_ENCRYPTION_CONTEXT))
658 f2fs_set_encrypted_inode(inode);
659 f2fs_mark_inode_dirty_sync(inode, true);
660 if (!error && S_ISDIR(inode->i_mode))
661 set_sbi_flag(F2FS_I_SB(inode), SBI_NEED_CP);
662 exit:
663 kzfree(base_addr);
664 return error;
665 }
666
667 int f2fs_setxattr(struct inode *inode, int index, const char *name,
668 const void *value, size_t size,
669 struct page *ipage, int flags)
670 {
671 struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
672 int err;
673
674 /* this case is only from init_inode_metadata */
675 if (ipage)
676 return __f2fs_setxattr(inode, index, name, value,
677 size, ipage, flags);
678 f2fs_balance_fs(sbi, true);
679
680 f2fs_lock_op(sbi);
681 /* protect xattr_ver */
682 down_write(&F2FS_I(inode)->i_sem);
683 err = __f2fs_setxattr(inode, index, name, value, size, ipage, flags);
684 up_write(&F2FS_I(inode)->i_sem);
685 f2fs_unlock_op(sbi);
686
687 f2fs_update_time(sbi, REQ_TIME);
688 return err;
689 }