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Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[linux-2.6-block.git] / fs / posix_acl.c
CommitLineData
1da177e4 1/*
5c8ebd57 2 * Copyright (C) 2002,2003 by Andreas Gruenbacher <a.gruenbacher@computer.org>
1da177e4 3 *
5c8ebd57
CH		 4 * Fixes from William Schumacher incorporated on 15 March 2001.
5 * (Reported by Charles Bertsch, <CBertsch@microtest.com>).
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
04c57f45 24static struct posix_acl **acl_by_type(struct inode *inode, int type)
0afaa120
AM		 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}
0afaa120
AM		 35
36struct posix_acl *get_cached_acl(struct inode *inode, int type)
37{
38 struct posix_acl **p = acl_by_type(inode, type);
b8a7a3a6
AG		 39 struct posix_acl *acl;
40
41 for (;;) {
42 rcu_read_lock();
43 acl = rcu_dereference(*p);
44 if (!acl || is_uncached_acl(acl) ||
45 atomic_inc_not_zero(&acl->a_refcount))
46 break;
47 rcu_read_unlock();
48 cpu_relax();
0afaa120 49 }
b8a7a3a6 50 rcu_read_unlock();
0afaa120
AM		 51 return acl;
52}
53EXPORT_SYMBOL(get_cached_acl);
54
55struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type)
56{
57 return rcu_dereference(*acl_by_type(inode, type));
58}
59EXPORT_SYMBOL(get_cached_acl_rcu);
60
61void set_cached_acl(struct inode *inode, int type, struct posix_acl *acl)
62{
63 struct posix_acl **p = acl_by_type(inode, type);
64 struct posix_acl *old;
b8a7a3a6
AG		 65
66 old = xchg(p, posix_acl_dup(acl));
67 if (!is_uncached_acl(old))
0afaa120
AM		 68 posix_acl_release(old);
69}
70EXPORT_SYMBOL(set_cached_acl);
71
b8a7a3a6 72static void __forget_cached_acl(struct posix_acl **p)
0afaa120 73{
0afaa120 74 struct posix_acl *old;
b8a7a3a6
AG		 75
76 old = xchg(p, ACL_NOT_CACHED);
77 if (!is_uncached_acl(old))
0afaa120
AM		 78 posix_acl_release(old);
79}
b8a7a3a6
AG		 80
81void forget_cached_acl(struct inode *inode, int type)
82{
83 __forget_cached_acl(acl_by_type(inode, type));
84}
0afaa120
AM		 85EXPORT_SYMBOL(forget_cached_acl);
86
87void forget_all_cached_acls(struct inode *inode)
88{
b8a7a3a6
AG		 89 __forget_cached_acl(&inode->i_acl);
90 __forget_cached_acl(&inode->i_default_acl);
0afaa120
AM		 91}
92EXPORT_SYMBOL(forget_all_cached_acls);
1da177e4 93
2982baa2
CH		 94struct posix_acl *get_acl(struct inode *inode, int type)
95{
b8a7a3a6
AG		 96 void *sentinel;
97 struct posix_acl **p;
2982baa2
CH		 98 struct posix_acl *acl;
99
b8a7a3a6
AG		 100 /*
101 * The sentinel is used to detect when another operation like
102 * set_cached_acl() or forget_cached_acl() races with get_acl().
103 * It is guaranteed that is_uncached_acl(sentinel) is true.
104 */
105
2982baa2 106 acl = get_cached_acl(inode, type);
b8a7a3a6 107 if (!is_uncached_acl(acl))
2982baa2
CH		 108 return acl;
109
110 if (!IS_POSIXACL(inode))
111 return NULL;
112
b8a7a3a6
AG		 113 sentinel = uncached_acl_sentinel(current);
114 p = acl_by_type(inode, type);
115
116 /*
117 * If the ACL isn't being read yet, set our sentinel. Otherwise, the
118 * current value of the ACL will not be ACL_NOT_CACHED and so our own
119 * sentinel will not be set; another task will update the cache. We
120 * could wait for that other task to complete its job, but it's easier
121 * to just call ->get_acl to fetch the ACL ourself. (This is going to
122 * be an unlikely race.)
123 */
124 if (cmpxchg(p, ACL_NOT_CACHED, sentinel) != ACL_NOT_CACHED)
125 /* fall through */ ;
126
2982baa2 127 /*
b8a7a3a6
AG		 128 * Normally, the ACL returned by ->get_acl will be cached.
129 * A filesystem can prevent that by calling
130 * forget_cached_acl(inode, type) in ->get_acl.
2982baa2
CH		 131 *
132 * If the filesystem doesn't have a get_acl() function at all, we'll
133 * just create the negative cache entry.
134 */
135 if (!inode->i_op->get_acl) {
136 set_cached_acl(inode, type, NULL);
137 return NULL;
138 }
b8a7a3a6
AG		 139 acl = inode->i_op->get_acl(inode, type);
140
141 if (IS_ERR(acl)) {
142 /*
143 * Remove our sentinel so that we don't block future attempts
144 * to cache the ACL.
145 */
146 cmpxchg(p, sentinel, ACL_NOT_CACHED);
147 return acl;
148 }
149
150 /*
151 * Cache the result, but only if our sentinel is still in place.
152 */
153 posix_acl_dup(acl);
154 if (unlikely(cmpxchg(p, sentinel, acl) != sentinel))
155 posix_acl_release(acl);
156 return acl;
2982baa2
CH		 157}
158EXPORT_SYMBOL(get_acl);
159
f61f6da0
CL		 160/*
161 * Init a fresh posix_acl
162 */
163void
164posix_acl_init(struct posix_acl *acl, int count)
165{
166 atomic_set(&acl->a_refcount, 1);
167 acl->a_count = count;
168}
0afaa120 169EXPORT_SYMBOL(posix_acl_init);
f61f6da0 170
1da177e4
LT		 171/*
172 * Allocate a new ACL with the specified number of entries.
173 */
174struct posix_acl *
dd0fc66f 175posix_acl_alloc(int count, gfp_t flags)
1da177e4
LT		 176{
177 const size_t size = sizeof(struct posix_acl) +
178 count * sizeof(struct posix_acl_entry);
179 struct posix_acl *acl = kmalloc(size, flags);
f61f6da0
CL		 180 if (acl)
181 posix_acl_init(acl, count);
1da177e4
LT		 182 return acl;
183}
0afaa120 184EXPORT_SYMBOL(posix_acl_alloc);
1da177e4
LT		 185
186/*
187 * Clone an ACL.
188 */
edde854e 189static struct posix_acl *
dd0fc66f 190posix_acl_clone(const struct posix_acl *acl, gfp_t flags)
1da177e4
LT		 191{
192 struct posix_acl *clone = NULL;
193
194 if (acl) {
195 int size = sizeof(struct posix_acl) + acl->a_count *
196 sizeof(struct posix_acl_entry);
52978be6
AD		 197 clone = kmemdup(acl, size, flags);
198 if (clone)
1da177e4 199 atomic_set(&clone->a_refcount, 1);
1da177e4
LT		 200 }
201 return clone;
202}
203
204/*
205 * Check if an acl is valid. Returns 0 if it is, or -E... otherwise.
206 */
207int
0d4d717f 208posix_acl_valid(struct user_namespace *user_ns, const struct posix_acl *acl)
1da177e4
LT		 209{
210 const struct posix_acl_entry *pa, *pe;
211 int state = ACL_USER_OBJ;
1da177e4
LT		 212 int needs_mask = 0;
213
214 FOREACH_ACL_ENTRY(pa, acl, pe) {
215 if (pa->e_perm & ~(ACL_READ|ACL_WRITE|ACL_EXECUTE))
216 return -EINVAL;
217 switch (pa->e_tag) {
218 case ACL_USER_OBJ:
219 if (state == ACL_USER_OBJ) {
1da177e4
LT		 220 state = ACL_USER;
221 break;
222 }
223 return -EINVAL;
224
225 case ACL_USER:
226 if (state != ACL_USER)
227 return -EINVAL;
0d4d717f 228 if (!kuid_has_mapping(user_ns, pa->e_uid))
1da177e4 229 return -EINVAL;
1da177e4
LT		 230 needs_mask = 1;
231 break;
232
233 case ACL_GROUP_OBJ:
234 if (state == ACL_USER) {
1da177e4
LT		 235 state = ACL_GROUP;
236 break;
237 }
238 return -EINVAL;
239
240 case ACL_GROUP:
241 if (state != ACL_GROUP)
242 return -EINVAL;
0d4d717f 243 if (!kgid_has_mapping(user_ns, pa->e_gid))
2f6f0654 244 return -EINVAL;
1da177e4
LT		 245 needs_mask = 1;
246 break;
247
248 case ACL_MASK:
249 if (state != ACL_GROUP)
250 return -EINVAL;
251 state = ACL_OTHER;
252 break;
253
254 case ACL_OTHER:
255 if (state == ACL_OTHER ||
256 (state == ACL_GROUP && !needs_mask)) {
257 state = 0;
258 break;
259 }
260 return -EINVAL;
261
262 default:
263 return -EINVAL;
264 }
265 }
266 if (state == 0)
267 return 0;
268 return -EINVAL;
269}
0afaa120 270EXPORT_SYMBOL(posix_acl_valid);
1da177e4
LT		 271
272/*
273 * Returns 0 if the acl can be exactly represented in the traditional
274 * file mode permission bits, or else 1. Returns -E... on error.
275 */
276int
d6952123 277posix_acl_equiv_mode(const struct posix_acl *acl, umode_t *mode_p)
1da177e4
LT		 278{
279 const struct posix_acl_entry *pa, *pe;
d6952123 280 umode_t mode = 0;
1da177e4
LT		 281 int not_equiv = 0;
282
50c6e282
CH		 283 /*
284 * A null ACL can always be presented as mode bits.
285 */
286 if (!acl)
287 return 0;
288
1da177e4
LT		 289 FOREACH_ACL_ENTRY(pa, acl, pe) {
290 switch (pa->e_tag) {
291 case ACL_USER_OBJ:
292 mode |= (pa->e_perm & S_IRWXO) << 6;
293 break;
294 case ACL_GROUP_OBJ:
295 mode |= (pa->e_perm & S_IRWXO) << 3;
296 break;
297 case ACL_OTHER:
298 mode |= pa->e_perm & S_IRWXO;
299 break;
300 case ACL_MASK:
301 mode = (mode & ~S_IRWXG) |
302 ((pa->e_perm & S_IRWXO) << 3);
303 not_equiv = 1;
304 break;
305 case ACL_USER:
306 case ACL_GROUP:
307 not_equiv = 1;
308 break;
309 default:
310 return -EINVAL;
311 }
312 }
313 if (mode_p)
314 *mode_p = (*mode_p & ~S_IRWXUGO) | mode;
315 return not_equiv;
316}
0afaa120 317EXPORT_SYMBOL(posix_acl_equiv_mode);
1da177e4
LT		 318
319/*
320 * Create an ACL representing the file mode permission bits of an inode.
321 */
322struct posix_acl *
3a5fba19 323posix_acl_from_mode(umode_t mode, gfp_t flags)
1da177e4
LT		 324{
325 struct posix_acl *acl = posix_acl_alloc(3, flags);
326 if (!acl)
327 return ERR_PTR(-ENOMEM);
328
329 acl->a_entries[0].e_tag = ACL_USER_OBJ;
1da177e4
LT		 330 acl->a_entries[0].e_perm = (mode & S_IRWXU) >> 6;
331
332 acl->a_entries[1].e_tag = ACL_GROUP_OBJ;
1da177e4
LT		 333 acl->a_entries[1].e_perm = (mode & S_IRWXG) >> 3;
334
335 acl->a_entries[2].e_tag = ACL_OTHER;
1da177e4
LT		 336 acl->a_entries[2].e_perm = (mode & S_IRWXO);
337 return acl;
338}
0afaa120 339EXPORT_SYMBOL(posix_acl_from_mode);
1da177e4
LT		 340
341/*
342 * Return 0 if current is granted want access to the inode
343 * by the acl. Returns -E... otherwise.
344 */
345int
346posix_acl_permission(struct inode *inode, const struct posix_acl *acl, int want)
347{
348 const struct posix_acl_entry *pa, *pe, *mask_obj;
349 int found = 0;
350
d124b60a
AG		 351 want &= MAY_READ | MAY_WRITE | MAY_EXEC | MAY_NOT_BLOCK;
352
1da177e4
LT		 353 FOREACH_ACL_ENTRY(pa, acl, pe) {
354 switch(pa->e_tag) {
355 case ACL_USER_OBJ:
356 /* (May have been checked already) */
2f6f0654 357 if (uid_eq(inode->i_uid, current_fsuid()))
1da177e4
LT		 358 goto check_perm;
359 break;
360 case ACL_USER:
2f6f0654 361 if (uid_eq(pa->e_uid, current_fsuid()))
1da177e4
LT		 362 goto mask;
363 break;
364 case ACL_GROUP_OBJ:
365 if (in_group_p(inode->i_gid)) {
366 found = 1;
367 if ((pa->e_perm & want) == want)
368 goto mask;
369 }
370 break;
371 case ACL_GROUP:
2f6f0654 372 if (in_group_p(pa->e_gid)) {
1da177e4
LT		 373 found = 1;
374 if ((pa->e_perm & want) == want)
375 goto mask;
376 }
377 break;
378 case ACL_MASK:
379 break;
380 case ACL_OTHER:
381 if (found)
382 return -EACCES;
383 else
384 goto check_perm;
385 default:
386 return -EIO;
387 }
388 }
389 return -EIO;
390
391mask:
392 for (mask_obj = pa+1; mask_obj != pe; mask_obj++) {
393 if (mask_obj->e_tag == ACL_MASK) {
394 if ((pa->e_perm & mask_obj->e_perm & want) == want)
395 return 0;
396 return -EACCES;
397 }
398 }
399
400check_perm:
401 if ((pa->e_perm & want) == want)
402 return 0;
403 return -EACCES;
404}
405
406/*
407 * Modify acl when creating a new inode. The caller must ensure the acl is
408 * only referenced once.
409 *
410 * mode_p initially must contain the mode parameter to the open() / creat()
411 * system calls. All permissions that are not granted by the acl are removed.
412 * The permissions in the acl are changed to reflect the mode_p parameter.
413 */
d3fb6120 414static int posix_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)
1da177e4
LT		 415{
416 struct posix_acl_entry *pa, *pe;
417 struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
d3fb6120 418 umode_t mode = *mode_p;
1da177e4
LT		 419 int not_equiv = 0;
420
421 /* assert(atomic_read(acl->a_refcount) == 1); */
422
423 FOREACH_ACL_ENTRY(pa, acl, pe) {
424 switch(pa->e_tag) {
425 case ACL_USER_OBJ:
426 pa->e_perm &= (mode >> 6) | ~S_IRWXO;
427 mode &= (pa->e_perm << 6) | ~S_IRWXU;
428 break;
429
430 case ACL_USER:
431 case ACL_GROUP:
432 not_equiv = 1;
433 break;
434
435 case ACL_GROUP_OBJ:
436 group_obj = pa;
437 break;
438
439 case ACL_OTHER:
440 pa->e_perm &= mode | ~S_IRWXO;
441 mode &= pa->e_perm | ~S_IRWXO;
442 break;
443
444 case ACL_MASK:
445 mask_obj = pa;
446 not_equiv = 1;
447 break;
448
449 default:
450 return -EIO;
451 }
452 }
453
454 if (mask_obj) {
455 mask_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
456 mode &= (mask_obj->e_perm << 3) | ~S_IRWXG;
457 } else {
458 if (!group_obj)
459 return -EIO;
460 group_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
461 mode &= (group_obj->e_perm << 3) | ~S_IRWXG;
462 }
463
464 *mode_p = (*mode_p & ~S_IRWXUGO) | mode;
465 return not_equiv;
466}
467
468/*
469 * Modify the ACL for the chmod syscall.
470 */
5bf3258f 471static int __posix_acl_chmod_masq(struct posix_acl *acl, umode_t mode)
1da177e4
LT		 472{
473 struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
474 struct posix_acl_entry *pa, *pe;
475
476 /* assert(atomic_read(acl->a_refcount) == 1); */
477
478 FOREACH_ACL_ENTRY(pa, acl, pe) {
479 switch(pa->e_tag) {
480 case ACL_USER_OBJ:
481 pa->e_perm = (mode & S_IRWXU) >> 6;
482 break;
483
484 case ACL_USER:
485 case ACL_GROUP:
486 break;
487
488 case ACL_GROUP_OBJ:
489 group_obj = pa;
490 break;
491
492 case ACL_MASK:
493 mask_obj = pa;
494 break;
495
496 case ACL_OTHER:
497 pa->e_perm = (mode & S_IRWXO);
498 break;
499
500 default:
501 return -EIO;
502 }
503 }
504
505 if (mask_obj) {
506 mask_obj->e_perm = (mode & S_IRWXG) >> 3;
507 } else {
508 if (!group_obj)
509 return -EIO;
510 group_obj->e_perm = (mode & S_IRWXG) >> 3;
511 }
512
513 return 0;
514}
bc26ab5f 515
826cae2f 516int
37bc1539 517__posix_acl_create(struct posix_acl **acl, gfp_t gfp, umode_t *mode_p)
826cae2f
AV		 518{
519 struct posix_acl *clone = posix_acl_clone(*acl, gfp);
520 int err = -ENOMEM;
521 if (clone) {
522 err = posix_acl_create_masq(clone, mode_p);
523 if (err < 0) {
524 posix_acl_release(clone);
525 clone = NULL;
526 }
527 }
528 posix_acl_release(*acl);
529 *acl = clone;
530 return err;
531}
37bc1539 532EXPORT_SYMBOL(__posix_acl_create);
826cae2f 533
bc26ab5f 534int
5bf3258f 535__posix_acl_chmod(struct posix_acl **acl, gfp_t gfp, umode_t mode)
bc26ab5f
AV		 536{
537 struct posix_acl *clone = posix_acl_clone(*acl, gfp);
538 int err = -ENOMEM;
539 if (clone) {
5bf3258f 540 err = __posix_acl_chmod_masq(clone, mode);
bc26ab5f
AV		 541 if (err) {
542 posix_acl_release(clone);
543 clone = NULL;
544 }
545 }
546 posix_acl_release(*acl);
547 *acl = clone;
548 return err;
549}
5bf3258f
CH		 550EXPORT_SYMBOL(__posix_acl_chmod);
551
552int
37bc1539 553posix_acl_chmod(struct inode *inode, umode_t mode)
5bf3258f
CH		 554{
555 struct posix_acl *acl;
556 int ret = 0;
557
558 if (!IS_POSIXACL(inode))
559 return 0;
560 if (!inode->i_op->set_acl)
561 return -EOPNOTSUPP;
562
563 acl = get_acl(inode, ACL_TYPE_ACCESS);
789b663a
TM		 564 if (IS_ERR_OR_NULL(acl)) {
565 if (acl == ERR_PTR(-EOPNOTSUPP))
566 return 0;
5bf3258f 567 return PTR_ERR(acl);
789b663a 568 }
5bf3258f 569
37bc1539 570 ret = __posix_acl_chmod(&acl, GFP_KERNEL, mode);
5bf3258f
CH		 571 if (ret)
572 return ret;
573 ret = inode->i_op->set_acl(inode, acl, ACL_TYPE_ACCESS);
574 posix_acl_release(acl);
575 return ret;
576}
bc26ab5f 577EXPORT_SYMBOL(posix_acl_chmod);
5c8ebd57 578
37bc1539
CH		 579int
580posix_acl_create(struct inode *dir, umode_t *mode,
581 struct posix_acl **default_acl, struct posix_acl **acl)
582{
583 struct posix_acl *p;
c0c3a718 584 struct posix_acl *clone;
37bc1539
CH		 585 int ret;
586
c0c3a718
DC		 587 *acl = NULL;
588 *default_acl = NULL;
589
37bc1539 590 if (S_ISLNK(*mode) || !IS_POSIXACL(dir))
c0c3a718 591 return 0;
37bc1539
CH		 592
593 p = get_acl(dir, ACL_TYPE_DEFAULT);
c0c3a718
DC		 594 if (!p || p == ERR_PTR(-EOPNOTSUPP)) {
595 *mode &= ~current_umask();
596 return 0;
37bc1539 597 }
c0c3a718
DC		 598 if (IS_ERR(p))
599 return PTR_ERR(p);
37bc1539 600
c0c3a718
DC		 601 clone = posix_acl_clone(p, GFP_NOFS);
602 if (!clone)
fed0b588 603 goto no_mem;
37bc1539 604
c0c3a718 605 ret = posix_acl_create_masq(clone, mode);
fed0b588
OS		 606 if (ret < 0)
607 goto no_mem_clone;
37bc1539 608
c0c3a718
DC		 609 if (ret == 0)
610 posix_acl_release(clone);
611 else
612 *acl = clone;
37bc1539 613
c0c3a718 614 if (!S_ISDIR(*mode))
37bc1539 615 posix_acl_release(p);
c0c3a718 616 else
37bc1539 617 *default_acl = p;
37bc1539 618
37bc1539 619 return 0;
fed0b588
OS		 620
621no_mem_clone:
c0c3a718 622 posix_acl_release(clone);
fed0b588
OS		 623no_mem:
624 posix_acl_release(p);
625 return -ENOMEM;
37bc1539
CH		 626}
627EXPORT_SYMBOL_GPL(posix_acl_create);
628
5c8ebd57
CH		 629/*
630 * Fix up the uids and gids in posix acl extended attributes in place.
631 */
632static void posix_acl_fix_xattr_userns(
633 struct user_namespace *to, struct user_namespace *from,
634 void *value, size_t size)
635{
636 posix_acl_xattr_header *header = (posix_acl_xattr_header *)value;
637 posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end;
638 int count;
639 kuid_t uid;
640 kgid_t gid;
641
642 if (!value)
643 return;
644 if (size < sizeof(posix_acl_xattr_header))
645 return;
646 if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
647 return;
648
649 count = posix_acl_xattr_count(size);
650 if (count < 0)
651 return;
652 if (count == 0)
653 return;
654
655 for (end = entry + count; entry != end; entry++) {
656 switch(le16_to_cpu(entry->e_tag)) {
657 case ACL_USER:
658 uid = make_kuid(from, le32_to_cpu(entry->e_id));
659 entry->e_id = cpu_to_le32(from_kuid(to, uid));
660 break;
661 case ACL_GROUP:
662 gid = make_kgid(from, le32_to_cpu(entry->e_id));
663 entry->e_id = cpu_to_le32(from_kgid(to, gid));
664 break;
665 default:
666 break;
667 }
668 }
669}
670
671void posix_acl_fix_xattr_from_user(void *value, size_t size)
672{
673 struct user_namespace *user_ns = current_user_ns();
674 if (user_ns == &init_user_ns)
675 return;
676 posix_acl_fix_xattr_userns(&init_user_ns, user_ns, value, size);
677}
678
679void posix_acl_fix_xattr_to_user(void *value, size_t size)
680{
681 struct user_namespace *user_ns = current_user_ns();
682 if (user_ns == &init_user_ns)
683 return;
684 posix_acl_fix_xattr_userns(user_ns, &init_user_ns, value, size);
685}
686
687/*
688 * Convert from extended attribute to in-memory representation.
689 */
690struct posix_acl *
691posix_acl_from_xattr(struct user_namespace *user_ns,
692 const void *value, size_t size)
693{
694 posix_acl_xattr_header *header = (posix_acl_xattr_header *)value;
695 posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end;
696 int count;
697 struct posix_acl *acl;
698 struct posix_acl_entry *acl_e;
699
700 if (!value)
701 return NULL;
702 if (size < sizeof(posix_acl_xattr_header))
703 return ERR_PTR(-EINVAL);
704 if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
705 return ERR_PTR(-EOPNOTSUPP);
706
707 count = posix_acl_xattr_count(size);
708 if (count < 0)
709 return ERR_PTR(-EINVAL);
710 if (count == 0)
711 return NULL;
712
713 acl = posix_acl_alloc(count, GFP_NOFS);
714 if (!acl)
715 return ERR_PTR(-ENOMEM);
716 acl_e = acl->a_entries;
717
718 for (end = entry + count; entry != end; acl_e++, entry++) {
719 acl_e->e_tag = le16_to_cpu(entry->e_tag);
720 acl_e->e_perm = le16_to_cpu(entry->e_perm);
721
722 switch(acl_e->e_tag) {
723 case ACL_USER_OBJ:
724 case ACL_GROUP_OBJ:
725 case ACL_MASK:
726 case ACL_OTHER:
727 break;
728
729 case ACL_USER:
730 acl_e->e_uid =
731 make_kuid(user_ns,
732 le32_to_cpu(entry->e_id));
733 if (!uid_valid(acl_e->e_uid))
734 goto fail;
735 break;
736 case ACL_GROUP:
737 acl_e->e_gid =
738 make_kgid(user_ns,
739 le32_to_cpu(entry->e_id));
740 if (!gid_valid(acl_e->e_gid))
741 goto fail;
742 break;
743
744 default:
745 goto fail;
746 }
747 }
748 return acl;
749
750fail:
751 posix_acl_release(acl);
752 return ERR_PTR(-EINVAL);
753}
754EXPORT_SYMBOL (posix_acl_from_xattr);
755
756/*
757 * Convert from in-memory to extended attribute representation.
758 */
759int
760posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl,
761 void *buffer, size_t size)
762{
763 posix_acl_xattr_header *ext_acl = (posix_acl_xattr_header *)buffer;
47ba9734 764 posix_acl_xattr_entry *ext_entry;
5c8ebd57
CH		 765 int real_size, n;
766
767 real_size = posix_acl_xattr_size(acl->a_count);
768 if (!buffer)
769 return real_size;
770 if (real_size > size)
771 return -ERANGE;
47ba9734
DC		 772
773 ext_entry = ext_acl->a_entries;
5c8ebd57
CH		 774 ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);
775
776 for (n=0; n < acl->a_count; n++, ext_entry++) {
777 const struct posix_acl_entry *acl_e = &acl->a_entries[n];
778 ext_entry->e_tag = cpu_to_le16(acl_e->e_tag);
779 ext_entry->e_perm = cpu_to_le16(acl_e->e_perm);
780 switch(acl_e->e_tag) {
781 case ACL_USER:
782 ext_entry->e_id =
783 cpu_to_le32(from_kuid(user_ns, acl_e->e_uid));
784 break;
785 case ACL_GROUP:
786 ext_entry->e_id =
787 cpu_to_le32(from_kgid(user_ns, acl_e->e_gid));
788 break;
789 default:
790 ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID);
791 break;
792 }
793 }
794 return real_size;
795}
796EXPORT_SYMBOL (posix_acl_to_xattr);
2aeccbe9
CH		 797
798static int
d9a82a04 799posix_acl_xattr_get(const struct xattr_handler *handler,
b296821a
AV		 800 struct dentry *unused, struct inode *inode,
801 const char *name, void *value, size_t size)
2aeccbe9
CH		 802{
803 struct posix_acl *acl;
804 int error;
805
b296821a 806 if (!IS_POSIXACL(inode))
2aeccbe9 807 return -EOPNOTSUPP;
b296821a 808 if (S_ISLNK(inode->i_mode))
2aeccbe9
CH		 809 return -EOPNOTSUPP;
810
b296821a 811 acl = get_acl(inode, handler->flags);
2aeccbe9
CH		 812 if (IS_ERR(acl))
813 return PTR_ERR(acl);
814 if (acl == NULL)
815 return -ENODATA;
816
817 error = posix_acl_to_xattr(&init_user_ns, acl, value, size);
818 posix_acl_release(acl);
819
820 return error;
821}
822
485e71e8
AG		 823int
824set_posix_acl(struct inode *inode, int type, struct posix_acl *acl)
2aeccbe9 825{
2aeccbe9
CH		 826 if (!IS_POSIXACL(inode))
827 return -EOPNOTSUPP;
828 if (!inode->i_op->set_acl)
829 return -EOPNOTSUPP;
830
485e71e8
AG		 831 if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
832 return acl ? -EACCES : 0;
2aeccbe9
CH		 833 if (!inode_owner_or_capable(inode))
834 return -EPERM;
835
485e71e8 836 if (acl) {
a867d734 837 int ret = posix_acl_valid(inode->i_sb->s_user_ns, acl);
485e71e8
AG		 838 if (ret)
839 return ret;
840 }
841 return inode->i_op->set_acl(inode, acl, type);
842}
843EXPORT_SYMBOL(set_posix_acl);
844
845static int
846posix_acl_xattr_set(const struct xattr_handler *handler,
847 struct dentry *unused, struct inode *inode,
848 const char *name, const void *value,
849 size_t size, int flags)
850{
851 struct posix_acl *acl = NULL;
852 int ret;
853
2aeccbe9
CH		 854 if (value) {
855 acl = posix_acl_from_xattr(&init_user_ns, value, size);
856 if (IS_ERR(acl))
857 return PTR_ERR(acl);
2aeccbe9 858 }
485e71e8 859 ret = set_posix_acl(inode, handler->flags, acl);
2aeccbe9
CH		 860 posix_acl_release(acl);
861 return ret;
862}
863
764a5c6b
AG		 864static bool
865posix_acl_xattr_list(struct dentry *dentry)
2aeccbe9 866{
764a5c6b 867 return IS_POSIXACL(d_backing_inode(dentry));
2aeccbe9
CH		 868}
869
870const struct xattr_handler posix_acl_access_xattr_handler = {
98e9cb57 871 .name = XATTR_NAME_POSIX_ACL_ACCESS,
2aeccbe9
CH		 872 .flags = ACL_TYPE_ACCESS,
873 .list = posix_acl_xattr_list,
874 .get = posix_acl_xattr_get,
875 .set = posix_acl_xattr_set,
876};
877EXPORT_SYMBOL_GPL(posix_acl_access_xattr_handler);
878
879const struct xattr_handler posix_acl_default_xattr_handler = {
98e9cb57 880 .name = XATTR_NAME_POSIX_ACL_DEFAULT,
2aeccbe9
CH		 881 .flags = ACL_TYPE_DEFAULT,
882 .list = posix_acl_xattr_list,
883 .get = posix_acl_xattr_get,
884 .set = posix_acl_xattr_set,
885};
886EXPORT_SYMBOL_GPL(posix_acl_default_xattr_handler);
feda821e
CH		 887
888int simple_set_acl(struct inode *inode, struct posix_acl *acl, int type)
889{
890 int error;
891
892 if (type == ACL_TYPE_ACCESS) {
893 error = posix_acl_equiv_mode(acl, &inode->i_mode);
894 if (error < 0)
895 return 0;
896 if (error == 0)
897 acl = NULL;
898 }
899
900 inode->i_ctime = CURRENT_TIME;
901 set_cached_acl(inode, type, acl);
902 return 0;
903}
904
905int simple_acl_create(struct inode *dir, struct inode *inode)
906{
907 struct posix_acl *default_acl, *acl;
908 int error;
909
910 error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
911 if (error)
912 return error;
913
914 set_cached_acl(inode, ACL_TYPE_DEFAULT, default_acl);
915 set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
916
917 if (default_acl)
918 posix_acl_release(default_acl);
919 if (acl)
920 posix_acl_release(acl);
921 return 0;
922}
Linux 6.x block layer and io_uring tree(s)