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[linux.git] / fs / posix_acl.c
CommitLineData
1da177e4 1/*
5c8ebd57 2 * Copyright (C) 2002,2003 by Andreas Gruenbacher <[email protected]>
1da177e4 3 *
5c8ebd57
CH		 4 * Fixes from William Schumacher incorporated on 15 March 2001.
5 * (Reported by Charles Bertsch, <[email protected]>).
1da177e4
LT		 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>
60063497 15#include <linux/atomic.h>
1da177e4
LT		 16#include <linux/fs.h>
17#include <linux/sched.h>
18#include <linux/posix_acl.h>
5c8ebd57 19#include <linux/posix_acl_xattr.h>
2aeccbe9 20#include <linux/xattr.h>
630d9c47 21#include <linux/export.h>
5c8ebd57 22#include <linux/user_namespace.h>
1da177e4 23
0afaa120
AM		 24struct posix_acl **acl_by_type(struct inode *inode, int type)
25{
26 switch (type) {
27 case ACL_TYPE_ACCESS:
28 return &inode->i_acl;
29 case ACL_TYPE_DEFAULT:
30 return &inode->i_default_acl;
31 default:
32 BUG();
33 }
34}
35EXPORT_SYMBOL(acl_by_type);
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 = ACCESS_ONCE(*p);
41 if (acl) {
42 spin_lock(&inode->i_lock);
43 acl = *p;
44 if (acl != ACL_NOT_CACHED)
45 acl = posix_acl_dup(acl);
46 spin_unlock(&inode->i_lock);
47 }
48 return acl;
49}
50EXPORT_SYMBOL(get_cached_acl);
51
52struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type)
53{
54 return rcu_dereference(*acl_by_type(inode, type));
55}
56EXPORT_SYMBOL(get_cached_acl_rcu);
57
58void set_cached_acl(struct inode *inode, int type, struct posix_acl *acl)
59{
60 struct posix_acl **p = acl_by_type(inode, type);
61 struct posix_acl *old;
62 spin_lock(&inode->i_lock);
63 old = *p;
64 rcu_assign_pointer(*p, posix_acl_dup(acl));
65 spin_unlock(&inode->i_lock);
66 if (old != ACL_NOT_CACHED)
67 posix_acl_release(old);
68}
69EXPORT_SYMBOL(set_cached_acl);
70
71void forget_cached_acl(struct inode *inode, int type)
72{
73 struct posix_acl **p = acl_by_type(inode, type);
74 struct posix_acl *old;
75 spin_lock(&inode->i_lock);
76 old = *p;
77 *p = ACL_NOT_CACHED;
78 spin_unlock(&inode->i_lock);
79 if (old != ACL_NOT_CACHED)
80 posix_acl_release(old);
81}
82EXPORT_SYMBOL(forget_cached_acl);
83
84void forget_all_cached_acls(struct inode *inode)
85{
86 struct posix_acl *old_access, *old_default;
87 spin_lock(&inode->i_lock);
88 old_access = inode->i_acl;
89 old_default = inode->i_default_acl;
90 inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
91 spin_unlock(&inode->i_lock);
92 if (old_access != ACL_NOT_CACHED)
93 posix_acl_release(old_access);
94 if (old_default != ACL_NOT_CACHED)
95 posix_acl_release(old_default);
96}
97EXPORT_SYMBOL(forget_all_cached_acls);
1da177e4 98
2982baa2
CH		 99struct posix_acl *get_acl(struct inode *inode, int type)
100{
101 struct posix_acl *acl;
102
103 acl = get_cached_acl(inode, type);
104 if (acl != ACL_NOT_CACHED)
105 return acl;
106
107 if (!IS_POSIXACL(inode))
108 return NULL;
109
110 /*
111 * A filesystem can force a ACL callback by just never filling the
112 * ACL cache. But normally you'd fill the cache either at inode
113 * instantiation time, or on the first ->get_acl call.
114 *
115 * If the filesystem doesn't have a get_acl() function at all, we'll
116 * just create the negative cache entry.
117 */
118 if (!inode->i_op->get_acl) {
119 set_cached_acl(inode, type, NULL);
120 return NULL;
121 }
122 return inode->i_op->get_acl(inode, type);
123}
124EXPORT_SYMBOL(get_acl);
125
f61f6da0
CL		 126/*
127 * Init a fresh posix_acl
128 */
129void
130posix_acl_init(struct posix_acl *acl, int count)
131{
132 atomic_set(&acl->a_refcount, 1);
133 acl->a_count = count;
134}
0afaa120 135EXPORT_SYMBOL(posix_acl_init);
f61f6da0 136
1da177e4
LT		 137/*
138 * Allocate a new ACL with the specified number of entries.
139 */
140struct posix_acl *
dd0fc66f 141posix_acl_alloc(int count, gfp_t flags)
1da177e4
LT		 142{
143 const size_t size = sizeof(struct posix_acl) +
144 count * sizeof(struct posix_acl_entry);
145 struct posix_acl *acl = kmalloc(size, flags);
f61f6da0
CL		 146 if (acl)
147 posix_acl_init(acl, count);
1da177e4
LT		 148 return acl;
149}
0afaa120 150EXPORT_SYMBOL(posix_acl_alloc);
1da177e4
LT		 151
152/*
153 * Clone an ACL.
154 */
edde854e 155static struct posix_acl *
dd0fc66f 156posix_acl_clone(const struct posix_acl *acl, gfp_t flags)
1da177e4
LT		 157{
158 struct posix_acl *clone = NULL;
159
160 if (acl) {
161 int size = sizeof(struct posix_acl) + acl->a_count *
162 sizeof(struct posix_acl_entry);
52978be6
AD		 163 clone = kmemdup(acl, size, flags);
164 if (clone)
1da177e4 165 atomic_set(&clone->a_refcount, 1);
1da177e4
LT		 166 }
167 return clone;
168}
169
170/*
171 * Check if an acl is valid. Returns 0 if it is, or -E... otherwise.
172 */
173int
174posix_acl_valid(const struct posix_acl *acl)
175{
176 const struct posix_acl_entry *pa, *pe;
177 int state = ACL_USER_OBJ;
1da177e4
LT		 178 int needs_mask = 0;
179
180 FOREACH_ACL_ENTRY(pa, acl, pe) {
181 if (pa->e_perm & ~(ACL_READ|ACL_WRITE|ACL_EXECUTE))
182 return -EINVAL;
183 switch (pa->e_tag) {
184 case ACL_USER_OBJ:
185 if (state == ACL_USER_OBJ) {
1da177e4
LT		 186 state = ACL_USER;
187 break;
188 }
189 return -EINVAL;
190
191 case ACL_USER:
192 if (state != ACL_USER)
193 return -EINVAL;
2f6f0654 194 if (!uid_valid(pa->e_uid))
1da177e4 195 return -EINVAL;
1da177e4
LT		 196 needs_mask = 1;
197 break;
198
199 case ACL_GROUP_OBJ:
200 if (state == ACL_USER) {
1da177e4
LT		 201 state = ACL_GROUP;
202 break;
203 }
204 return -EINVAL;
205
206 case ACL_GROUP:
207 if (state != ACL_GROUP)
208 return -EINVAL;
2f6f0654
EB		 209 if (!gid_valid(pa->e_gid))
210 return -EINVAL;
1da177e4
LT		 211 needs_mask = 1;
212 break;
213
214 case ACL_MASK:
215 if (state != ACL_GROUP)
216 return -EINVAL;
217 state = ACL_OTHER;
218 break;
219
220 case ACL_OTHER:
221 if (state == ACL_OTHER ||
222 (state == ACL_GROUP && !needs_mask)) {
223 state = 0;
224 break;
225 }
226 return -EINVAL;
227
228 default:
229 return -EINVAL;
230 }
231 }
232 if (state == 0)
233 return 0;
234 return -EINVAL;
235}
0afaa120 236EXPORT_SYMBOL(posix_acl_valid);
1da177e4
LT		 237
238/*
239 * Returns 0 if the acl can be exactly represented in the traditional
240 * file mode permission bits, or else 1. Returns -E... on error.
241 */
242int
d6952123 243posix_acl_equiv_mode(const struct posix_acl *acl, umode_t *mode_p)
1da177e4
LT		 244{
245 const struct posix_acl_entry *pa, *pe;
d6952123 246 umode_t mode = 0;
1da177e4
LT		 247 int not_equiv = 0;
248
50c6e282
CH		 249 /*
250 * A null ACL can always be presented as mode bits.
251 */
252 if (!acl)
253 return 0;
254
1da177e4
LT		 255 FOREACH_ACL_ENTRY(pa, acl, pe) {
256 switch (pa->e_tag) {
257 case ACL_USER_OBJ:
258 mode |= (pa->e_perm & S_IRWXO) << 6;
259 break;
260 case ACL_GROUP_OBJ:
261 mode |= (pa->e_perm & S_IRWXO) << 3;
262 break;
263 case ACL_OTHER:
264 mode |= pa->e_perm & S_IRWXO;
265 break;
266 case ACL_MASK:
267 mode = (mode & ~S_IRWXG) |
268 ((pa->e_perm & S_IRWXO) << 3);
269 not_equiv = 1;
270 break;
271 case ACL_USER:
272 case ACL_GROUP:
273 not_equiv = 1;
274 break;
275 default:
276 return -EINVAL;
277 }
278 }
279 if (mode_p)
280 *mode_p = (*mode_p & ~S_IRWXUGO) | mode;
281 return not_equiv;
282}
0afaa120 283EXPORT_SYMBOL(posix_acl_equiv_mode);
1da177e4
LT		 284
285/*
286 * Create an ACL representing the file mode permission bits of an inode.
287 */
288struct posix_acl *
3a5fba19 289posix_acl_from_mode(umode_t mode, gfp_t flags)
1da177e4
LT		 290{
291 struct posix_acl *acl = posix_acl_alloc(3, flags);
292 if (!acl)
293 return ERR_PTR(-ENOMEM);
294
295 acl->a_entries[0].e_tag = ACL_USER_OBJ;
1da177e4
LT		 296 acl->a_entries[0].e_perm = (mode & S_IRWXU) >> 6;
297
298 acl->a_entries[1].e_tag = ACL_GROUP_OBJ;
1da177e4
LT		 299 acl->a_entries[1].e_perm = (mode & S_IRWXG) >> 3;
300
301 acl->a_entries[2].e_tag = ACL_OTHER;
1da177e4
LT		 302 acl->a_entries[2].e_perm = (mode & S_IRWXO);
303 return acl;
304}
0afaa120 305EXPORT_SYMBOL(posix_acl_from_mode);
1da177e4
LT		 306
307/*
308 * Return 0 if current is granted want access to the inode
309 * by the acl. Returns -E... otherwise.
310 */
311int
312posix_acl_permission(struct inode *inode, const struct posix_acl *acl, int want)
313{
314 const struct posix_acl_entry *pa, *pe, *mask_obj;
315 int found = 0;
316
d124b60a
AG		 317 want &= MAY_READ | MAY_WRITE | MAY_EXEC | MAY_NOT_BLOCK;
318
1da177e4
LT		 319 FOREACH_ACL_ENTRY(pa, acl, pe) {
320 switch(pa->e_tag) {
321 case ACL_USER_OBJ:
322 /* (May have been checked already) */
2f6f0654 323 if (uid_eq(inode->i_uid, current_fsuid()))
1da177e4
LT		 324 goto check_perm;
325 break;
326 case ACL_USER:
2f6f0654 327 if (uid_eq(pa->e_uid, current_fsuid()))
1da177e4
LT		 328 goto mask;
329 break;
330 case ACL_GROUP_OBJ:
331 if (in_group_p(inode->i_gid)) {
332 found = 1;
333 if ((pa->e_perm & want) == want)
334 goto mask;
335 }
336 break;
337 case ACL_GROUP:
2f6f0654 338 if (in_group_p(pa->e_gid)) {
1da177e4
LT		 339 found = 1;
340 if ((pa->e_perm & want) == want)
341 goto mask;
342 }
343 break;
344 case ACL_MASK:
345 break;
346 case ACL_OTHER:
347 if (found)
348 return -EACCES;
349 else
350 goto check_perm;
351 default:
352 return -EIO;
353 }
354 }
355 return -EIO;
356
357mask:
358 for (mask_obj = pa+1; mask_obj != pe; mask_obj++) {
359 if (mask_obj->e_tag == ACL_MASK) {
360 if ((pa->e_perm & mask_obj->e_perm & want) == want)
361 return 0;
362 return -EACCES;
363 }
364 }
365
366check_perm:
367 if ((pa->e_perm & want) == want)
368 return 0;
369 return -EACCES;
370}
371
372/*
373 * Modify acl when creating a new inode. The caller must ensure the acl is
374 * only referenced once.
375 *
376 * mode_p initially must contain the mode parameter to the open() / creat()
377 * system calls. All permissions that are not granted by the acl are removed.
378 * The permissions in the acl are changed to reflect the mode_p parameter.
379 */
d3fb6120 380static int posix_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)
1da177e4
LT		 381{
382 struct posix_acl_entry *pa, *pe;
383 struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
d3fb6120 384 umode_t mode = *mode_p;
1da177e4
LT		 385 int not_equiv = 0;
386
387 /* assert(atomic_read(acl->a_refcount) == 1); */
388
389 FOREACH_ACL_ENTRY(pa, acl, pe) {
390 switch(pa->e_tag) {
391 case ACL_USER_OBJ:
392 pa->e_perm &= (mode >> 6) | ~S_IRWXO;
393 mode &= (pa->e_perm << 6) | ~S_IRWXU;
394 break;
395
396 case ACL_USER:
397 case ACL_GROUP:
398 not_equiv = 1;
399 break;
400
401 case ACL_GROUP_OBJ:
402 group_obj = pa;
403 break;
404
405 case ACL_OTHER:
406 pa->e_perm &= mode | ~S_IRWXO;
407 mode &= pa->e_perm | ~S_IRWXO;
408 break;
409
410 case ACL_MASK:
411 mask_obj = pa;
412 not_equiv = 1;
413 break;
414
415 default:
416 return -EIO;
417 }
418 }
419
420 if (mask_obj) {
421 mask_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
422 mode &= (mask_obj->e_perm << 3) | ~S_IRWXG;
423 } else {
424 if (!group_obj)
425 return -EIO;
426 group_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
427 mode &= (group_obj->e_perm << 3) | ~S_IRWXG;
428 }
429
430 *mode_p = (*mode_p & ~S_IRWXUGO) | mode;
431 return not_equiv;
432}
433
434/*
435 * Modify the ACL for the chmod syscall.
436 */
5bf3258f 437static int __posix_acl_chmod_masq(struct posix_acl *acl, umode_t mode)
1da177e4
LT		 438{
439 struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
440 struct posix_acl_entry *pa, *pe;
441
442 /* assert(atomic_read(acl->a_refcount) == 1); */
443
444 FOREACH_ACL_ENTRY(pa, acl, pe) {
445 switch(pa->e_tag) {
446 case ACL_USER_OBJ:
447 pa->e_perm = (mode & S_IRWXU) >> 6;
448 break;
449
450 case ACL_USER:
451 case ACL_GROUP:
452 break;
453
454 case ACL_GROUP_OBJ:
455 group_obj = pa;
456 break;
457
458 case ACL_MASK:
459 mask_obj = pa;
460 break;
461
462 case ACL_OTHER:
463 pa->e_perm = (mode & S_IRWXO);
464 break;
465
466 default:
467 return -EIO;
468 }
469 }
470
471 if (mask_obj) {
472 mask_obj->e_perm = (mode & S_IRWXG) >> 3;
473 } else {
474 if (!group_obj)
475 return -EIO;
476 group_obj->e_perm = (mode & S_IRWXG) >> 3;
477 }
478
479 return 0;
480}
bc26ab5f 481
826cae2f 482int
37bc1539 483__posix_acl_create(struct posix_acl **acl, gfp_t gfp, umode_t *mode_p)
826cae2f
AV		 484{
485 struct posix_acl *clone = posix_acl_clone(*acl, gfp);
486 int err = -ENOMEM;
487 if (clone) {
488 err = posix_acl_create_masq(clone, mode_p);
489 if (err < 0) {
490 posix_acl_release(clone);
491 clone = NULL;
492 }
493 }
494 posix_acl_release(*acl);
495 *acl = clone;
496 return err;
497}
37bc1539 498EXPORT_SYMBOL(__posix_acl_create);
826cae2f 499
bc26ab5f 500int
5bf3258f 501__posix_acl_chmod(struct posix_acl **acl, gfp_t gfp, umode_t mode)
bc26ab5f
AV		 502{
503 struct posix_acl *clone = posix_acl_clone(*acl, gfp);
504 int err = -ENOMEM;
505 if (clone) {
5bf3258f 506 err = __posix_acl_chmod_masq(clone, mode);
bc26ab5f
AV		 507 if (err) {
508 posix_acl_release(clone);
509 clone = NULL;
510 }
511 }
512 posix_acl_release(*acl);
513 *acl = clone;
514 return err;
515}
5bf3258f
CH		 516EXPORT_SYMBOL(__posix_acl_chmod);
517
518int
37bc1539 519posix_acl_chmod(struct inode *inode, umode_t mode)
5bf3258f
CH		 520{
521 struct posix_acl *acl;
522 int ret = 0;
523
524 if (!IS_POSIXACL(inode))
525 return 0;
526 if (!inode->i_op->set_acl)
527 return -EOPNOTSUPP;
528
529 acl = get_acl(inode, ACL_TYPE_ACCESS);
789b663a
TM		 530 if (IS_ERR_OR_NULL(acl)) {
531 if (acl == ERR_PTR(-EOPNOTSUPP))
532 return 0;
5bf3258f 533 return PTR_ERR(acl);
789b663a 534 }
5bf3258f 535
37bc1539 536 ret = __posix_acl_chmod(&acl, GFP_KERNEL, mode);
5bf3258f
CH		 537 if (ret)
538 return ret;
539 ret = inode->i_op->set_acl(inode, acl, ACL_TYPE_ACCESS);
540 posix_acl_release(acl);
541 return ret;
542}
bc26ab5f 543EXPORT_SYMBOL(posix_acl_chmod);
5c8ebd57 544
37bc1539
CH		 545int
546posix_acl_create(struct inode *dir, umode_t *mode,
547 struct posix_acl **default_acl, struct posix_acl **acl)
548{
549 struct posix_acl *p;
550 int ret;
551
552 if (S_ISLNK(*mode) || !IS_POSIXACL(dir))
553 goto no_acl;
554
555 p = get_acl(dir, ACL_TYPE_DEFAULT);
789b663a
TM		 556 if (IS_ERR(p)) {
557 if (p == ERR_PTR(-EOPNOTSUPP))
558 goto apply_umask;
37bc1539 559 return PTR_ERR(p);
37bc1539
CH		 560 }
561
789b663a
TM		 562 if (!p)
563 goto apply_umask;
564
37bc1539
CH		 565 *acl = posix_acl_clone(p, GFP_NOFS);
566 if (!*acl)
fed0b588 567 goto no_mem;
37bc1539
CH		 568
569 ret = posix_acl_create_masq(*acl, mode);
fed0b588
OS		 570 if (ret < 0)
571 goto no_mem_clone;
37bc1539
CH		 572
573 if (ret == 0) {
574 posix_acl_release(*acl);
575 *acl = NULL;
576 }
577
578 if (!S_ISDIR(*mode)) {
579 posix_acl_release(p);
580 *default_acl = NULL;
581 } else {
582 *default_acl = p;
583 }
584 return 0;
585
789b663a
TM		 586apply_umask:
587 *mode &= ~current_umask();
37bc1539
CH		 588no_acl:
589 *default_acl = NULL;
590 *acl = NULL;
591 return 0;
fed0b588
OS		 592
593no_mem_clone:
594 posix_acl_release(*acl);
595no_mem:
596 posix_acl_release(p);
597 return -ENOMEM;
37bc1539
CH		 598}
599EXPORT_SYMBOL_GPL(posix_acl_create);
600
5c8ebd57
CH		 601/*
602 * Fix up the uids and gids in posix acl extended attributes in place.
603 */
604static void posix_acl_fix_xattr_userns(
605 struct user_namespace *to, struct user_namespace *from,
606 void *value, size_t size)
607{
608 posix_acl_xattr_header *header = (posix_acl_xattr_header *)value;
609 posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end;
610 int count;
611 kuid_t uid;
612 kgid_t gid;
613
614 if (!value)
615 return;
616 if (size < sizeof(posix_acl_xattr_header))
617 return;
618 if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
619 return;
620
621 count = posix_acl_xattr_count(size);
622 if (count < 0)
623 return;
624 if (count == 0)
625 return;
626
627 for (end = entry + count; entry != end; entry++) {
628 switch(le16_to_cpu(entry->e_tag)) {
629 case ACL_USER:
630 uid = make_kuid(from, le32_to_cpu(entry->e_id));
631 entry->e_id = cpu_to_le32(from_kuid(to, uid));
632 break;
633 case ACL_GROUP:
634 gid = make_kgid(from, le32_to_cpu(entry->e_id));
635 entry->e_id = cpu_to_le32(from_kgid(to, gid));
636 break;
637 default:
638 break;
639 }
640 }
641}
642
643void posix_acl_fix_xattr_from_user(void *value, size_t size)
644{
645 struct user_namespace *user_ns = current_user_ns();
646 if (user_ns == &init_user_ns)
647 return;
648 posix_acl_fix_xattr_userns(&init_user_ns, user_ns, value, size);
649}
650
651void posix_acl_fix_xattr_to_user(void *value, size_t size)
652{
653 struct user_namespace *user_ns = current_user_ns();
654 if (user_ns == &init_user_ns)
655 return;
656 posix_acl_fix_xattr_userns(user_ns, &init_user_ns, value, size);
657}
658
659/*
660 * Convert from extended attribute to in-memory representation.
661 */
662struct posix_acl *
663posix_acl_from_xattr(struct user_namespace *user_ns,
664 const void *value, size_t size)
665{
666 posix_acl_xattr_header *header = (posix_acl_xattr_header *)value;
667 posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end;
668 int count;
669 struct posix_acl *acl;
670 struct posix_acl_entry *acl_e;
671
672 if (!value)
673 return NULL;
674 if (size < sizeof(posix_acl_xattr_header))
675 return ERR_PTR(-EINVAL);
676 if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
677 return ERR_PTR(-EOPNOTSUPP);
678
679 count = posix_acl_xattr_count(size);
680 if (count < 0)
681 return ERR_PTR(-EINVAL);
682 if (count == 0)
683 return NULL;
684
685 acl = posix_acl_alloc(count, GFP_NOFS);
686 if (!acl)
687 return ERR_PTR(-ENOMEM);
688 acl_e = acl->a_entries;
689
690 for (end = entry + count; entry != end; acl_e++, entry++) {
691 acl_e->e_tag = le16_to_cpu(entry->e_tag);
692 acl_e->e_perm = le16_to_cpu(entry->e_perm);
693
694 switch(acl_e->e_tag) {
695 case ACL_USER_OBJ:
696 case ACL_GROUP_OBJ:
697 case ACL_MASK:
698 case ACL_OTHER:
699 break;
700
701 case ACL_USER:
702 acl_e->e_uid =
703 make_kuid(user_ns,
704 le32_to_cpu(entry->e_id));
705 if (!uid_valid(acl_e->e_uid))
706 goto fail;
707 break;
708 case ACL_GROUP:
709 acl_e->e_gid =
710 make_kgid(user_ns,
711 le32_to_cpu(entry->e_id));
712 if (!gid_valid(acl_e->e_gid))
713 goto fail;
714 break;
715
716 default:
717 goto fail;
718 }
719 }
720 return acl;
721
722fail:
723 posix_acl_release(acl);
724 return ERR_PTR(-EINVAL);
725}
726EXPORT_SYMBOL (posix_acl_from_xattr);
727
728/*
729 * Convert from in-memory to extended attribute representation.
730 */
731int
732posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl,
733 void *buffer, size_t size)
734{
735 posix_acl_xattr_header *ext_acl = (posix_acl_xattr_header *)buffer;
47ba9734 736 posix_acl_xattr_entry *ext_entry;
5c8ebd57
CH		 737 int real_size, n;
738
739 real_size = posix_acl_xattr_size(acl->a_count);
740 if (!buffer)
741 return real_size;
742 if (real_size > size)
743 return -ERANGE;
47ba9734
DC		 744
745 ext_entry = ext_acl->a_entries;
5c8ebd57
CH		 746 ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);
747
748 for (n=0; n < acl->a_count; n++, ext_entry++) {
749 const struct posix_acl_entry *acl_e = &acl->a_entries[n];
750 ext_entry->e_tag = cpu_to_le16(acl_e->e_tag);
751 ext_entry->e_perm = cpu_to_le16(acl_e->e_perm);
752 switch(acl_e->e_tag) {
753 case ACL_USER:
754 ext_entry->e_id =
755 cpu_to_le32(from_kuid(user_ns, acl_e->e_uid));
756 break;
757 case ACL_GROUP:
758 ext_entry->e_id =
759 cpu_to_le32(from_kgid(user_ns, acl_e->e_gid));
760 break;
761 default:
762 ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID);
763 break;
764 }
765 }
766 return real_size;
767}
768EXPORT_SYMBOL (posix_acl_to_xattr);
2aeccbe9
CH		 769
770static int
771posix_acl_xattr_get(struct dentry *dentry, const char *name,
772 void *value, size_t size, int type)
773{
774 struct posix_acl *acl;
775 int error;
776
bb668734 777 if (!IS_POSIXACL(d_backing_inode(dentry)))
2aeccbe9 778 return -EOPNOTSUPP;
e36cb0b8 779 if (d_is_symlink(dentry))
2aeccbe9
CH		 780 return -EOPNOTSUPP;
781
bb668734 782 acl = get_acl(d_backing_inode(dentry), type);
2aeccbe9
CH		 783 if (IS_ERR(acl))
784 return PTR_ERR(acl);
785 if (acl == NULL)
786 return -ENODATA;
787
788 error = posix_acl_to_xattr(&init_user_ns, acl, value, size);
789 posix_acl_release(acl);
790
791 return error;
792}
793
794static int
795posix_acl_xattr_set(struct dentry *dentry, const char *name,
796 const void *value, size_t size, int flags, int type)
797{
bb668734 798 struct inode *inode = d_backing_inode(dentry);
2aeccbe9
CH		 799 struct posix_acl *acl = NULL;
800 int ret;
801
802 if (!IS_POSIXACL(inode))
803 return -EOPNOTSUPP;
804 if (!inode->i_op->set_acl)
805 return -EOPNOTSUPP;
806
807 if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
808 return value ? -EACCES : 0;
809 if (!inode_owner_or_capable(inode))
810 return -EPERM;
811
812 if (value) {
813 acl = posix_acl_from_xattr(&init_user_ns, value, size);
814 if (IS_ERR(acl))
815 return PTR_ERR(acl);
816
817 if (acl) {
818 ret = posix_acl_valid(acl);
819 if (ret)
820 goto out;
821 }
822 }
823
824 ret = inode->i_op->set_acl(inode, acl, type);
825out:
826 posix_acl_release(acl);
827 return ret;
828}
829
830static size_t
831posix_acl_xattr_list(struct dentry *dentry, char *list, size_t list_size,
832 const char *name, size_t name_len, int type)
833{
834 const char *xname;
835 size_t size;
836
bb668734 837 if (!IS_POSIXACL(d_backing_inode(dentry)))
2aeccbe9 838 return -EOPNOTSUPP;
e36cb0b8 839 if (d_is_symlink(dentry))
2aeccbe9
CH		 840 return -EOPNOTSUPP;
841
842 if (type == ACL_TYPE_ACCESS)
843 xname = POSIX_ACL_XATTR_ACCESS;
844 else
845 xname = POSIX_ACL_XATTR_DEFAULT;
846
847 size = strlen(xname) + 1;
848 if (list && size <= list_size)
849 memcpy(list, xname, size);
850 return size;
851}
852
853const struct xattr_handler posix_acl_access_xattr_handler = {
854 .prefix = POSIX_ACL_XATTR_ACCESS,
855 .flags = ACL_TYPE_ACCESS,
856 .list = posix_acl_xattr_list,
857 .get = posix_acl_xattr_get,
858 .set = posix_acl_xattr_set,
859};
860EXPORT_SYMBOL_GPL(posix_acl_access_xattr_handler);
861
862const struct xattr_handler posix_acl_default_xattr_handler = {
863 .prefix = POSIX_ACL_XATTR_DEFAULT,
864 .flags = ACL_TYPE_DEFAULT,
865 .list = posix_acl_xattr_list,
866 .get = posix_acl_xattr_get,
867 .set = posix_acl_xattr_set,
868};
869EXPORT_SYMBOL_GPL(posix_acl_default_xattr_handler);
feda821e
CH		 870
871int simple_set_acl(struct inode *inode, struct posix_acl *acl, int type)
872{
873 int error;
874
875 if (type == ACL_TYPE_ACCESS) {
876 error = posix_acl_equiv_mode(acl, &inode->i_mode);
877 if (error < 0)
878 return 0;
879 if (error == 0)
880 acl = NULL;
881 }
882
883 inode->i_ctime = CURRENT_TIME;
884 set_cached_acl(inode, type, acl);
885 return 0;
886}
887
888int simple_acl_create(struct inode *dir, struct inode *inode)
889{
890 struct posix_acl *default_acl, *acl;
891 int error;
892
893 error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
894 if (error)
895 return error;
896
897 set_cached_acl(inode, ACL_TYPE_DEFAULT, default_acl);
898 set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
899
900 if (default_acl)
901 posix_acl_release(default_acl);
902 if (acl)
903 posix_acl_release(acl);
904 return 0;
905}
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