1/*
2 * Copyright (C) 2002,2003 by Andreas Gruenbacher <a.gruenbacher@computer.org>
3 *
4 * Fixes from William Schumacher incorporated on 15 March 2001.
5 * (Reported by Charles Bertsch, <CBertsch@microtest.com>).
6 */
7
8/*
9 * This file contains generic functions for manipulating
10 * POSIX 1003.1e draft standard 17 ACLs.
11 */
12
13#include <linux/kernel.h>
14#include <linux/slab.h>
15#include <linux/atomic.h>
16#include <linux/fs.h>
17#include <linux/sched.h>
18#include <linux/cred.h>
19#include <linux/posix_acl.h>
20#include <linux/posix_acl_xattr.h>
21#include <linux/xattr.h>
22#include <linux/export.h>
23#include <linux/user_namespace.h>
24
25static struct posix_acl **acl_by_type(struct inode *inode, int type)
26{
27 switch (type) {
28 case ACL_TYPE_ACCESS:
29 return &inode->i_acl;
30 case ACL_TYPE_DEFAULT:
31 return &inode->i_default_acl;
32 default:
33 BUG();
34 }
35}
36
37struct posix_acl *get_cached_acl(struct inode *inode, int type)
38{
39 struct posix_acl **p = acl_by_type(inode, type);
40 struct posix_acl *acl;
41
42 for (;;) {
43 rcu_read_lock();
44 acl = rcu_dereference(*p);
45 if (!acl || is_uncached_acl(acl) ||
46 refcount_inc_not_zero(&acl->a_refcount))
47 break;
48 rcu_read_unlock();
49 cpu_relax();
50 }
51 rcu_read_unlock();
52 return acl;
53}
54EXPORT_SYMBOL(get_cached_acl);
55
56struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type)
57{
58 return rcu_dereference(*acl_by_type(inode, type));
59}
60EXPORT_SYMBOL(get_cached_acl_rcu);
61
62void set_cached_acl(struct inode *inode, int type, struct posix_acl *acl)
63{
64 struct posix_acl **p = acl_by_type(inode, type);
65 struct posix_acl *old;
66
67 old = xchg(p, posix_acl_dup(acl));
68 if (!is_uncached_acl(old))
69 posix_acl_release(old);
70}
71EXPORT_SYMBOL(set_cached_acl);
72
73static void __forget_cached_acl(struct posix_acl **p)
74{
75 struct posix_acl *old;
76
77 old = xchg(p, ACL_NOT_CACHED);
78 if (!is_uncached_acl(old))
79 posix_acl_release(old);
80}
81
82void forget_cached_acl(struct inode *inode, int type)
83{
84 __forget_cached_acl(acl_by_type(inode, type));
85}
86EXPORT_SYMBOL(forget_cached_acl);
87
88void forget_all_cached_acls(struct inode *inode)
89{
90 __forget_cached_acl(&inode->i_acl);
91 __forget_cached_acl(&inode->i_default_acl);
92}
93EXPORT_SYMBOL(forget_all_cached_acls);
94
95struct posix_acl *get_acl(struct inode *inode, int type)
96{
97 void *sentinel;
98 struct posix_acl **p;
99 struct posix_acl *acl;
100
101 /*
102 * The sentinel is used to detect when another operation like
103 * set_cached_acl() or forget_cached_acl() races with get_acl().
104 * It is guaranteed that is_uncached_acl(sentinel) is true.
105 */
106
107 acl = get_cached_acl(inode, type);
108 if (!is_uncached_acl(acl))
109 return acl;
110
111 if (!IS_POSIXACL(inode))
112 return NULL;
113
114 sentinel = uncached_acl_sentinel(current);
115 p = acl_by_type(inode, type);
116
117 /*
118 * If the ACL isn't being read yet, set our sentinel. Otherwise, the
119 * current value of the ACL will not be ACL_NOT_CACHED and so our own
120 * sentinel will not be set; another task will update the cache. We
121 * could wait for that other task to complete its job, but it's easier
122 * to just call ->get_acl to fetch the ACL ourself. (This is going to
123 * be an unlikely race.)
124 */
125 if (cmpxchg(p, ACL_NOT_CACHED, sentinel) != ACL_NOT_CACHED)
126 /* fall through */ ;
127
128 /*
129 * Normally, the ACL returned by ->get_acl will be cached.
130 * A filesystem can prevent that by calling
131 * forget_cached_acl(inode, type) in ->get_acl.
132 *
133 * If the filesystem doesn't have a get_acl() function at all, we'll
134 * just create the negative cache entry.
135 */
136 if (!inode->i_op->get_acl) {
137 set_cached_acl(inode, type, NULL);
138 return NULL;
139 }
140 acl = inode->i_op->get_acl(inode, type);
141
142 if (IS_ERR(acl)) {
143 /*
144 * Remove our sentinel so that we don't block future attempts
145 * to cache the ACL.
146 */
147 cmpxchg(p, sentinel, ACL_NOT_CACHED);
148 return acl;
149 }
150
151 /*
152 * Cache the result, but only if our sentinel is still in place.
153 */
154 posix_acl_dup(acl);
155 if (unlikely(cmpxchg(p, sentinel, acl) != sentinel))
156 posix_acl_release(acl);
157 return acl;
158}
159EXPORT_SYMBOL(get_acl);
160
161/*
162 * Init a fresh posix_acl
163 */
164void
165posix_acl_init(struct posix_acl *acl, int count)
166{
167 refcount_set(&acl->a_refcount, 1);
168 acl->a_count = count;
169}
170EXPORT_SYMBOL(posix_acl_init);
171
172/*
173 * Allocate a new ACL with the specified number of entries.
174 */
175struct posix_acl *
176posix_acl_alloc(int count, gfp_t flags)
177{
178 const size_t size = sizeof(struct posix_acl) +
179 count * sizeof(struct posix_acl_entry);
180 struct posix_acl *acl = kmalloc(size, flags);
181 if (acl)
182 posix_acl_init(acl, count);
183 return acl;
184}
185EXPORT_SYMBOL(posix_acl_alloc);
186
187/*
188 * Clone an ACL.
189 */
190static struct posix_acl *
191posix_acl_clone(const struct posix_acl *acl, gfp_t flags)
192{
193 struct posix_acl *clone = NULL;
194
195 if (acl) {
196 int size = sizeof(struct posix_acl) + acl->a_count *
197 sizeof(struct posix_acl_entry);
198 clone = kmemdup(acl, size, flags);
199 if (clone)
200 refcount_set(&clone->a_refcount, 1);
201 }
202 return clone;
203}
204
205/*
206 * Check if an acl is valid. Returns 0 if it is, or -E... otherwise.
207 */
208int
209posix_acl_valid(struct user_namespace *user_ns, const struct posix_acl *acl)
210{
211 const struct posix_acl_entry *pa, *pe;
212 int state = ACL_USER_OBJ;
213 int needs_mask = 0;
214
215 FOREACH_ACL_ENTRY(pa, acl, pe) {
216 if (pa->e_perm & ~(ACL_READ|ACL_WRITE|ACL_EXECUTE))
217 return -EINVAL;
218 switch (pa->e_tag) {
219 case ACL_USER_OBJ:
220 if (state == ACL_USER_OBJ) {
221 state = ACL_USER;
222 break;
223 }
224 return -EINVAL;
225
226 case ACL_USER:
227 if (state != ACL_USER)
228 return -EINVAL;
229 if (!kuid_has_mapping(user_ns, pa->e_uid))
230 return -EINVAL;
231 needs_mask = 1;
232 break;
233
234 case ACL_GROUP_OBJ:
235 if (state == ACL_USER) {
236 state = ACL_GROUP;
237 break;
238 }
239 return -EINVAL;
240
241 case ACL_GROUP:
242 if (state != ACL_GROUP)
243 return -EINVAL;
244 if (!kgid_has_mapping(user_ns, pa->e_gid))
245 return -EINVAL;
246 needs_mask = 1;
247 break;
248
249 case ACL_MASK:
250 if (state != ACL_GROUP)
251 return -EINVAL;
252 state = ACL_OTHER;
253 break;
254
255 case ACL_OTHER:
256 if (state == ACL_OTHER ||
257 (state == ACL_GROUP && !needs_mask)) {
258 state = 0;
259 break;
260 }
261 return -EINVAL;
262
263 default:
264 return -EINVAL;
265 }
266 }
267 if (state == 0)
268 return 0;
269 return -EINVAL;
270}
271EXPORT_SYMBOL(posix_acl_valid);
272
273/*
274 * Returns 0 if the acl can be exactly represented in the traditional
275 * file mode permission bits, or else 1. Returns -E... on error.
276 */
277int
278posix_acl_equiv_mode(const struct posix_acl *acl, umode_t *mode_p)
279{
280 const struct posix_acl_entry *pa, *pe;
281 umode_t mode = 0;
282 int not_equiv = 0;
283
284 /*
285 * A null ACL can always be presented as mode bits.
286 */
287 if (!acl)
288 return 0;
289
290 FOREACH_ACL_ENTRY(pa, acl, pe) {
291 switch (pa->e_tag) {
292 case ACL_USER_OBJ:
293 mode |= (pa->e_perm & S_IRWXO) << 6;
294 break;
295 case ACL_GROUP_OBJ:
296 mode |= (pa->e_perm & S_IRWXO) << 3;
297 break;
298 case ACL_OTHER:
299 mode |= pa->e_perm & S_IRWXO;
300 break;
301 case ACL_MASK:
302 mode = (mode & ~S_IRWXG) |
303 ((pa->e_perm & S_IRWXO) << 3);
304 not_equiv = 1;
305 break;
306 case ACL_USER:
307 case ACL_GROUP:
308 not_equiv = 1;
309 break;
310 default:
311 return -EINVAL;
312 }
313 }
314 if (mode_p)
315 *mode_p = (*mode_p & ~S_IRWXUGO) | mode;
316 return not_equiv;
317}
318EXPORT_SYMBOL(posix_acl_equiv_mode);
319
320/*
321 * Create an ACL representing the file mode permission bits of an inode.
322 */
323struct posix_acl *
324posix_acl_from_mode(umode_t mode, gfp_t flags)
325{
326 struct posix_acl *acl = posix_acl_alloc(3, flags);
327 if (!acl)
328 return ERR_PTR(-ENOMEM);
329
330 acl->a_entries[0].e_tag = ACL_USER_OBJ;
331 acl->a_entries[0].e_perm = (mode & S_IRWXU) >> 6;
332
333 acl->a_entries[1].e_tag = ACL_GROUP_OBJ;
334 acl->a_entries[1].e_perm = (mode & S_IRWXG) >> 3;
335
336 acl->a_entries[2].e_tag = ACL_OTHER;
337 acl->a_entries[2].e_perm = (mode & S_IRWXO);
338 return acl;
339}
340EXPORT_SYMBOL(posix_acl_from_mode);
341
342/*
343 * Return 0 if current is granted want access to the inode
344 * by the acl. Returns -E... otherwise.
345 */
346int
347posix_acl_permission(struct inode *inode, const struct posix_acl *acl, int want)
348{
349 const struct posix_acl_entry *pa, *pe, *mask_obj;
350 int found = 0;
351
352 want &= MAY_READ | MAY_WRITE | MAY_EXEC | MAY_NOT_BLOCK;
353
354 FOREACH_ACL_ENTRY(pa, acl, pe) {
355 switch(pa->e_tag) {
356 case ACL_USER_OBJ:
357 /* (May have been checked already) */
358 if (uid_eq(inode->i_uid, current_fsuid()))
359 goto check_perm;
360 break;
361 case ACL_USER:
362 if (uid_eq(pa->e_uid, current_fsuid()))
363 goto mask;
364 break;
365 case ACL_GROUP_OBJ:
366 if (in_group_p(inode->i_gid)) {
367 found = 1;
368 if ((pa->e_perm & want) == want)
369 goto mask;
370 }
371 break;
372 case ACL_GROUP:
373 if (in_group_p(pa->e_gid)) {
374 found = 1;
375 if ((pa->e_perm & want) == want)
376 goto mask;
377 }
378 break;
379 case ACL_MASK:
380 break;
381 case ACL_OTHER:
382 if (found)
383 return -EACCES;
384 else
385 goto check_perm;
386 default:
387 return -EIO;
388 }
389 }
390 return -EIO;
391
392mask:
393 for (mask_obj = pa+1; mask_obj != pe; mask_obj++) {
394 if (mask_obj->e_tag == ACL_MASK) {
395 if ((pa->e_perm & mask_obj->e_perm & want) == want)
396 return 0;
397 return -EACCES;
398 }
399 }
400
401check_perm:
402 if ((pa->e_perm & want) == want)
403 return 0;
404 return -EACCES;
405}
406
407/*
408 * Modify acl when creating a new inode. The caller must ensure the acl is
409 * only referenced once.
410 *
411 * mode_p initially must contain the mode parameter to the open() / creat()
412 * system calls. All permissions that are not granted by the acl are removed.
413 * The permissions in the acl are changed to reflect the mode_p parameter.
414 */
415static int posix_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)
416{
417 struct posix_acl_entry *pa, *pe;
418 struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
419 umode_t mode = *mode_p;
420 int not_equiv = 0;
421
422 /* assert(atomic_read(acl->a_refcount) == 1); */
423
424 FOREACH_ACL_ENTRY(pa, acl, pe) {
425 switch(pa->e_tag) {
426 case ACL_USER_OBJ:
427 pa->e_perm &= (mode >> 6) | ~S_IRWXO;
428 mode &= (pa->e_perm << 6) | ~S_IRWXU;
429 break;
430
431 case ACL_USER:
432 case ACL_GROUP:
433 not_equiv = 1;
434 break;
435
436 case ACL_GROUP_OBJ:
437 group_obj = pa;
438 break;
439
440 case ACL_OTHER:
441 pa->e_perm &= mode | ~S_IRWXO;
442 mode &= pa->e_perm | ~S_IRWXO;
443 break;
444
445 case ACL_MASK:
446 mask_obj = pa;
447 not_equiv = 1;
448 break;
449
450 default:
451 return -EIO;
452 }
453 }
454
455 if (mask_obj) {
456 mask_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
457 mode &= (mask_obj->e_perm << 3) | ~S_IRWXG;
458 } else {
459 if (!group_obj)
460 return -EIO;
461 group_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
462 mode &= (group_obj->e_perm << 3) | ~S_IRWXG;
463 }
464
465 *mode_p = (*mode_p & ~S_IRWXUGO) | mode;
466 return not_equiv;
467}
468
469/*
470 * Modify the ACL for the chmod syscall.
471 */
472static int __posix_acl_chmod_masq(struct posix_acl *acl, umode_t mode)
473{
474 struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
475 struct posix_acl_entry *pa, *pe;
476
477 /* assert(atomic_read(acl->a_refcount) == 1); */
478
479 FOREACH_ACL_ENTRY(pa, acl, pe) {
480 switch(pa->e_tag) {
481 case ACL_USER_OBJ:
482 pa->e_perm = (mode & S_IRWXU) >> 6;
483 break;
484
485 case ACL_USER:
486 case ACL_GROUP:
487 break;
488
489 case ACL_GROUP_OBJ:
490 group_obj = pa;
491 break;
492
493 case ACL_MASK:
494 mask_obj = pa;
495 break;
496
497 case ACL_OTHER:
498 pa->e_perm = (mode & S_IRWXO);
499 break;
500
501 default:
502 return -EIO;
503 }
504 }
505
506 if (mask_obj) {
507 mask_obj->e_perm = (mode & S_IRWXG) >> 3;
508 } else {
509 if (!group_obj)
510 return -EIO;
511 group_obj->e_perm = (mode & S_IRWXG) >> 3;
512 }
513
514 return 0;
515}
516
517int
518__posix_acl_create(struct posix_acl **acl, gfp_t gfp, umode_t *mode_p)
519{
520 struct posix_acl *clone = posix_acl_clone(*acl, gfp);
521 int err = -ENOMEM;
522 if (clone) {
523 err = posix_acl_create_masq(clone, mode_p);
524 if (err < 0) {
525 posix_acl_release(clone);
526 clone = NULL;
527 }
528 }
529 posix_acl_release(*acl);
530 *acl = clone;
531 return err;
532}
533EXPORT_SYMBOL(__posix_acl_create);
534
535int
536__posix_acl_chmod(struct posix_acl **acl, gfp_t gfp, umode_t mode)
537{
538 struct posix_acl *clone = posix_acl_clone(*acl, gfp);
539 int err = -ENOMEM;
540 if (clone) {
541 err = __posix_acl_chmod_masq(clone, mode);
542 if (err) {
543 posix_acl_release(clone);
544 clone = NULL;
545 }
546 }
547 posix_acl_release(*acl);
548 *acl = clone;
549 return err;
550}
551EXPORT_SYMBOL(__posix_acl_chmod);
552
553int
554posix_acl_chmod(struct inode *inode, umode_t mode)
555{
556 struct posix_acl *acl;
557 int ret = 0;
558
559 if (!IS_POSIXACL(inode))
560 return 0;
561 if (!inode->i_op->set_acl)
562 return -EOPNOTSUPP;
563
564 acl = get_acl(inode, ACL_TYPE_ACCESS);
565 if (IS_ERR_OR_NULL(acl)) {
566 if (acl == ERR_PTR(-EOPNOTSUPP))
567 return 0;
568 return PTR_ERR(acl);
569 }
570
571 ret = __posix_acl_chmod(&acl, GFP_KERNEL, mode);
572 if (ret)
573 return ret;
574 ret = inode->i_op->set_acl(inode, acl, ACL_TYPE_ACCESS);
575 posix_acl_release(acl);
576 return ret;
577}
578EXPORT_SYMBOL(posix_acl_chmod);
579
580int
581posix_acl_create(struct inode *dir, umode_t *mode,
582 struct posix_acl **default_acl, struct posix_acl **acl)
583{
584 struct posix_acl *p;
585 struct posix_acl *clone;
586 int ret;
587
588 *acl = NULL;
589 *default_acl = NULL;
590
591 if (S_ISLNK(*mode) || !IS_POSIXACL(dir))
592 return 0;
593
594 p = get_acl(dir, ACL_TYPE_DEFAULT);
595 if (!p || p == ERR_PTR(-EOPNOTSUPP)) {
596 *mode &= ~current_umask();
597 return 0;
598 }
599 if (IS_ERR(p))
600 return PTR_ERR(p);
601
602 ret = -ENOMEM;
603 clone = posix_acl_clone(p, GFP_NOFS);
604 if (!clone)
605 goto err_release;
606
607 ret = posix_acl_create_masq(clone, mode);
608 if (ret < 0)
609 goto err_release_clone;
610
611 if (ret == 0)
612 posix_acl_release(clone);
613 else
614 *acl = clone;
615
616 if (!S_ISDIR(*mode))
617 posix_acl_release(p);
618 else
619 *default_acl = p;
620
621 return 0;
622
623err_release_clone:
624 posix_acl_release(clone);
625err_release:
626 posix_acl_release(p);
627 return ret;
628}
629EXPORT_SYMBOL_GPL(posix_acl_create);
630
631/**
632 * posix_acl_update_mode - update mode in set_acl
633 *
634 * Update the file mode when setting an ACL: compute the new file permission
635 * bits based on the ACL. In addition, if the ACL is equivalent to the new
636 * file mode, set *acl to NULL to indicate that no ACL should be set.
637 *
638 * As with chmod, clear the setgit bit if the caller is not in the owning group
639 * or capable of CAP_FSETID (see inode_change_ok).
640 *
641 * Called from set_acl inode operations.
642 */
643int posix_acl_update_mode(struct inode *inode, umode_t *mode_p,
644 struct posix_acl **acl)
645{
646 umode_t mode = inode->i_mode;
647 int error;
648
649 error = posix_acl_equiv_mode(*acl, &mode);
650 if (error < 0)
651 return error;
652 if (error == 0)
653 *acl = NULL;
654 if (!in_group_p(inode->i_gid) &&
655 !capable_wrt_inode_uidgid(inode, CAP_FSETID))
656 mode &= ~S_ISGID;
657 *mode_p = mode;
658 return 0;
659}
660EXPORT_SYMBOL(posix_acl_update_mode);
661
662/*
663 * Fix up the uids and gids in posix acl extended attributes in place.
664 */
665static void posix_acl_fix_xattr_userns(
666 struct user_namespace *to, struct user_namespace *from,
667 void *value, size_t size)
668{
669 struct posix_acl_xattr_header *header = value;
670 struct posix_acl_xattr_entry *entry = (void *)(header + 1), *end;
671 int count;
672 kuid_t uid;
673 kgid_t gid;
674
675 if (!value)
676 return;
677 if (size < sizeof(struct posix_acl_xattr_header))
678 return;
679 if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
680 return;
681
682 count = posix_acl_xattr_count(size);
683 if (count < 0)
684 return;
685 if (count == 0)
686 return;
687
688 for (end = entry + count; entry != end; entry++) {
689 switch(le16_to_cpu(entry->e_tag)) {
690 case ACL_USER:
691 uid = make_kuid(from, le32_to_cpu(entry->e_id));
692 entry->e_id = cpu_to_le32(from_kuid(to, uid));
693 break;
694 case ACL_GROUP:
695 gid = make_kgid(from, le32_to_cpu(entry->e_id));
696 entry->e_id = cpu_to_le32(from_kgid(to, gid));
697 break;
698 default:
699 break;
700 }
701 }
702}
703
704void posix_acl_fix_xattr_from_user(void *value, size_t size)
705{
706 struct user_namespace *user_ns = current_user_ns();
707 if (user_ns == &init_user_ns)
708 return;
709 posix_acl_fix_xattr_userns(&init_user_ns, user_ns, value, size);
710}
711
712void posix_acl_fix_xattr_to_user(void *value, size_t size)
713{
714 struct user_namespace *user_ns = current_user_ns();
715 if (user_ns == &init_user_ns)
716 return;
717 posix_acl_fix_xattr_userns(user_ns, &init_user_ns, value, size);
718}
719
720/*
721 * Convert from extended attribute to in-memory representation.
722 */
723struct posix_acl *
724posix_acl_from_xattr(struct user_namespace *user_ns,
725 const void *value, size_t size)
726{
727 const struct posix_acl_xattr_header *header = value;
728 const struct posix_acl_xattr_entry *entry = (const void *)(header + 1), *end;
729 int count;
730 struct posix_acl *acl;
731 struct posix_acl_entry *acl_e;
732
733 if (!value)
734 return NULL;
735 if (size < sizeof(struct posix_acl_xattr_header))
736 return ERR_PTR(-EINVAL);
737 if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
738 return ERR_PTR(-EOPNOTSUPP);
739
740 count = posix_acl_xattr_count(size);
741 if (count < 0)
742 return ERR_PTR(-EINVAL);
743 if (count == 0)
744 return NULL;
745
746 acl = posix_acl_alloc(count, GFP_NOFS);
747 if (!acl)
748 return ERR_PTR(-ENOMEM);
749 acl_e = acl->a_entries;
750
751 for (end = entry + count; entry != end; acl_e++, entry++) {
752 acl_e->e_tag = le16_to_cpu(entry->e_tag);
753 acl_e->e_perm = le16_to_cpu(entry->e_perm);
754
755 switch(acl_e->e_tag) {
756 case ACL_USER_OBJ:
757 case ACL_GROUP_OBJ:
758 case ACL_MASK:
759 case ACL_OTHER:
760 break;
761
762 case ACL_USER:
763 acl_e->e_uid =
764 make_kuid(user_ns,
765 le32_to_cpu(entry->e_id));
766 if (!uid_valid(acl_e->e_uid))
767 goto fail;
768 break;
769 case ACL_GROUP:
770 acl_e->e_gid =
771 make_kgid(user_ns,
772 le32_to_cpu(entry->e_id));
773 if (!gid_valid(acl_e->e_gid))
774 goto fail;
775 break;
776
777 default:
778 goto fail;
779 }
780 }
781 return acl;
782
783fail:
784 posix_acl_release(acl);
785 return ERR_PTR(-EINVAL);
786}
787EXPORT_SYMBOL (posix_acl_from_xattr);
788
789/*
790 * Convert from in-memory to extended attribute representation.
791 */
792int
793posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl,
794 void *buffer, size_t size)
795{
796 struct posix_acl_xattr_header *ext_acl = buffer;
797 struct posix_acl_xattr_entry *ext_entry;
798 int real_size, n;
799
800 real_size = posix_acl_xattr_size(acl->a_count);
801 if (!buffer)
802 return real_size;
803 if (real_size > size)
804 return -ERANGE;
805
806 ext_entry = (void *)(ext_acl + 1);
807 ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);
808
809 for (n=0; n < acl->a_count; n++, ext_entry++) {
810 const struct posix_acl_entry *acl_e = &acl->a_entries[n];
811 ext_entry->e_tag = cpu_to_le16(acl_e->e_tag);
812 ext_entry->e_perm = cpu_to_le16(acl_e->e_perm);
813 switch(acl_e->e_tag) {
814 case ACL_USER:
815 ext_entry->e_id =
816 cpu_to_le32(from_kuid(user_ns, acl_e->e_uid));
817 break;
818 case ACL_GROUP:
819 ext_entry->e_id =
820 cpu_to_le32(from_kgid(user_ns, acl_e->e_gid));
821 break;
822 default:
823 ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID);
824 break;
825 }
826 }
827 return real_size;
828}
829EXPORT_SYMBOL (posix_acl_to_xattr);
830
831static int
832posix_acl_xattr_get(const struct xattr_handler *handler,
833 struct dentry *unused, struct inode *inode,
834 const char *name, void *value, size_t size)
835{
836 struct posix_acl *acl;
837 int error;
838
839 if (!IS_POSIXACL(inode))
840 return -EOPNOTSUPP;
841 if (S_ISLNK(inode->i_mode))
842 return -EOPNOTSUPP;
843
844 acl = get_acl(inode, handler->flags);
845 if (IS_ERR(acl))
846 return PTR_ERR(acl);
847 if (acl == NULL)
848 return -ENODATA;
849
850 error = posix_acl_to_xattr(&init_user_ns, acl, value, size);
851 posix_acl_release(acl);
852
853 return error;
854}
855
856int
857set_posix_acl(struct inode *inode, int type, struct posix_acl *acl)
858{
859 if (!IS_POSIXACL(inode))
860 return -EOPNOTSUPP;
861 if (!inode->i_op->set_acl)
862 return -EOPNOTSUPP;
863
864 if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
865 return acl ? -EACCES : 0;
866 if (!inode_owner_or_capable(inode))
867 return -EPERM;
868
869 if (acl) {
870 int ret = posix_acl_valid(inode->i_sb->s_user_ns, acl);
871 if (ret)
872 return ret;
873 }
874 return inode->i_op->set_acl(inode, acl, type);
875}
876EXPORT_SYMBOL(set_posix_acl);
877
878static int
879posix_acl_xattr_set(const struct xattr_handler *handler,
880 struct dentry *unused, struct inode *inode,
881 const char *name, const void *value,
882 size_t size, int flags)
883{
884 struct posix_acl *acl = NULL;
885 int ret;
886
887 if (value) {
888 acl = posix_acl_from_xattr(&init_user_ns, value, size);
889 if (IS_ERR(acl))
890 return PTR_ERR(acl);
891 }
892 ret = set_posix_acl(inode, handler->flags, acl);
893 posix_acl_release(acl);
894 return ret;
895}
896
897static bool
898posix_acl_xattr_list(struct dentry *dentry)
899{
900 return IS_POSIXACL(d_backing_inode(dentry));
901}
902
903const struct xattr_handler posix_acl_access_xattr_handler = {
904 .name = XATTR_NAME_POSIX_ACL_ACCESS,
905 .flags = ACL_TYPE_ACCESS,
906 .list = posix_acl_xattr_list,
907 .get = posix_acl_xattr_get,
908 .set = posix_acl_xattr_set,
909};
910EXPORT_SYMBOL_GPL(posix_acl_access_xattr_handler);
911
912const struct xattr_handler posix_acl_default_xattr_handler = {
913 .name = XATTR_NAME_POSIX_ACL_DEFAULT,
914 .flags = ACL_TYPE_DEFAULT,
915 .list = posix_acl_xattr_list,
916 .get = posix_acl_xattr_get,
917 .set = posix_acl_xattr_set,
918};
919EXPORT_SYMBOL_GPL(posix_acl_default_xattr_handler);
920
921int simple_set_acl(struct inode *inode, struct posix_acl *acl, int type)
922{
923 int error;
924
925 if (type == ACL_TYPE_ACCESS) {
926 error = posix_acl_update_mode(inode,
927 &inode->i_mode, &acl);
928 if (error)
929 return error;
930 }
931
932 inode->i_ctime = current_time(inode);
933 set_cached_acl(inode, type, acl);
934 return 0;
935}
936
937int simple_acl_create(struct inode *dir, struct inode *inode)
938{
939 struct posix_acl *default_acl, *acl;
940 int error;
941
942 error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
943 if (error)
944 return error;
945
946 set_cached_acl(inode, ACL_TYPE_DEFAULT, default_acl);
947 set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
948
949 if (default_acl)
950 posix_acl_release(default_acl);
951 if (acl)
952 posix_acl_release(acl);
953 return 0;
954}
955