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/posix_acl.h>
19 #include <linux/posix_acl_xattr.h>
20 #include <linux/xattr.h>
21 #include <linux/export.h>
22 #include <linux/user_namespace.h>
23
acl_by_type(struct inode * inode,int type)24 struct 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 }
35 EXPORT_SYMBOL(acl_by_type);
36
get_cached_acl(struct inode * inode,int type)37 struct 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 }
50 EXPORT_SYMBOL(get_cached_acl);
51
get_cached_acl_rcu(struct inode * inode,int type)52 struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type)
53 {
54 return rcu_dereference(*acl_by_type(inode, type));
55 }
56 EXPORT_SYMBOL(get_cached_acl_rcu);
57
set_cached_acl(struct inode * inode,int type,struct posix_acl * acl)58 void 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 }
69 EXPORT_SYMBOL(set_cached_acl);
70
forget_cached_acl(struct inode * inode,int type)71 void 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 }
82 EXPORT_SYMBOL(forget_cached_acl);
83
forget_all_cached_acls(struct inode * inode)84 void 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 }
97 EXPORT_SYMBOL(forget_all_cached_acls);
98
get_acl(struct inode * inode,int type)99 struct 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 }
124 EXPORT_SYMBOL(get_acl);
125
126 /*
127 * Init a fresh posix_acl
128 */
129 void
posix_acl_init(struct posix_acl * acl,int count)130 posix_acl_init(struct posix_acl *acl, int count)
131 {
132 atomic_set(&acl->a_refcount, 1);
133 acl->a_count = count;
134 }
135 EXPORT_SYMBOL(posix_acl_init);
136
137 /*
138 * Allocate a new ACL with the specified number of entries.
139 */
140 struct posix_acl *
posix_acl_alloc(int count,gfp_t flags)141 posix_acl_alloc(int count, gfp_t flags)
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);
146 if (acl)
147 posix_acl_init(acl, count);
148 return acl;
149 }
150 EXPORT_SYMBOL(posix_acl_alloc);
151
152 /*
153 * Clone an ACL.
154 */
155 static struct posix_acl *
posix_acl_clone(const struct posix_acl * acl,gfp_t flags)156 posix_acl_clone(const struct posix_acl *acl, gfp_t flags)
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);
163 clone = kmemdup(acl, size, flags);
164 if (clone)
165 atomic_set(&clone->a_refcount, 1);
166 }
167 return clone;
168 }
169
170 /*
171 * Check if an acl is valid. Returns 0 if it is, or -E... otherwise.
172 */
173 int
posix_acl_valid(const struct posix_acl * acl)174 posix_acl_valid(const struct posix_acl *acl)
175 {
176 const struct posix_acl_entry *pa, *pe;
177 int state = ACL_USER_OBJ;
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) {
186 state = ACL_USER;
187 break;
188 }
189 return -EINVAL;
190
191 case ACL_USER:
192 if (state != ACL_USER)
193 return -EINVAL;
194 if (!uid_valid(pa->e_uid))
195 return -EINVAL;
196 needs_mask = 1;
197 break;
198
199 case ACL_GROUP_OBJ:
200 if (state == ACL_USER) {
201 state = ACL_GROUP;
202 break;
203 }
204 return -EINVAL;
205
206 case ACL_GROUP:
207 if (state != ACL_GROUP)
208 return -EINVAL;
209 if (!gid_valid(pa->e_gid))
210 return -EINVAL;
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 }
236 EXPORT_SYMBOL(posix_acl_valid);
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 */
242 int
posix_acl_equiv_mode(const struct posix_acl * acl,umode_t * mode_p)243 posix_acl_equiv_mode(const struct posix_acl *acl, umode_t *mode_p)
244 {
245 const struct posix_acl_entry *pa, *pe;
246 umode_t mode = 0;
247 int not_equiv = 0;
248
249 /*
250 * A null ACL can always be presented as mode bits.
251 */
252 if (!acl)
253 return 0;
254
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 }
283 EXPORT_SYMBOL(posix_acl_equiv_mode);
284
285 /*
286 * Create an ACL representing the file mode permission bits of an inode.
287 */
288 struct posix_acl *
posix_acl_from_mode(umode_t mode,gfp_t flags)289 posix_acl_from_mode(umode_t mode, gfp_t flags)
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;
296 acl->a_entries[0].e_perm = (mode & S_IRWXU) >> 6;
297
298 acl->a_entries[1].e_tag = ACL_GROUP_OBJ;
299 acl->a_entries[1].e_perm = (mode & S_IRWXG) >> 3;
300
301 acl->a_entries[2].e_tag = ACL_OTHER;
302 acl->a_entries[2].e_perm = (mode & S_IRWXO);
303 return acl;
304 }
305 EXPORT_SYMBOL(posix_acl_from_mode);
306
307 /*
308 * Return 0 if current is granted want access to the inode
309 * by the acl. Returns -E... otherwise.
310 */
311 int
posix_acl_permission(struct inode * inode,const struct posix_acl * acl,int want)312 posix_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
317 want &= MAY_READ | MAY_WRITE | MAY_EXEC | MAY_NOT_BLOCK;
318
319 FOREACH_ACL_ENTRY(pa, acl, pe) {
320 switch(pa->e_tag) {
321 case ACL_USER_OBJ:
322 /* (May have been checked already) */
323 if (uid_eq(inode->i_uid, current_fsuid()))
324 goto check_perm;
325 break;
326 case ACL_USER:
327 if (uid_eq(pa->e_uid, current_fsuid()))
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:
338 if (in_group_p(pa->e_gid)) {
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
357 mask:
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
366 check_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 */
posix_acl_create_masq(struct posix_acl * acl,umode_t * mode_p)380 static int posix_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)
381 {
382 struct posix_acl_entry *pa, *pe;
383 struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
384 umode_t mode = *mode_p;
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 */
__posix_acl_chmod_masq(struct posix_acl * acl,umode_t mode)437 static int __posix_acl_chmod_masq(struct posix_acl *acl, umode_t mode)
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 }
481
482 int
__posix_acl_create(struct posix_acl ** acl,gfp_t gfp,umode_t * mode_p)483 __posix_acl_create(struct posix_acl **acl, gfp_t gfp, umode_t *mode_p)
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 }
498 EXPORT_SYMBOL(__posix_acl_create);
499
500 int
__posix_acl_chmod(struct posix_acl ** acl,gfp_t gfp,umode_t mode)501 __posix_acl_chmod(struct posix_acl **acl, gfp_t gfp, umode_t mode)
502 {
503 struct posix_acl *clone = posix_acl_clone(*acl, gfp);
504 int err = -ENOMEM;
505 if (clone) {
506 err = __posix_acl_chmod_masq(clone, mode);
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 }
516 EXPORT_SYMBOL(__posix_acl_chmod);
517
518 int
posix_acl_chmod(struct inode * inode,umode_t mode)519 posix_acl_chmod(struct inode *inode, umode_t mode)
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);
530 if (IS_ERR_OR_NULL(acl)) {
531 if (acl == ERR_PTR(-EOPNOTSUPP))
532 return 0;
533 return PTR_ERR(acl);
534 }
535
536 ret = __posix_acl_chmod(&acl, GFP_KERNEL, mode);
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 }
543 EXPORT_SYMBOL(posix_acl_chmod);
544
545 int
posix_acl_create(struct inode * dir,umode_t * mode,struct posix_acl ** default_acl,struct posix_acl ** acl)546 posix_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);
556 if (IS_ERR(p)) {
557 if (p == ERR_PTR(-EOPNOTSUPP))
558 goto apply_umask;
559 return PTR_ERR(p);
560 }
561
562 if (!p)
563 goto apply_umask;
564
565 *acl = posix_acl_clone(p, GFP_NOFS);
566 if (!*acl)
567 return -ENOMEM;
568
569 ret = posix_acl_create_masq(*acl, mode);
570 if (ret < 0) {
571 posix_acl_release(*acl);
572 return -ENOMEM;
573 }
574
575 if (ret == 0) {
576 posix_acl_release(*acl);
577 *acl = NULL;
578 }
579
580 if (!S_ISDIR(*mode)) {
581 posix_acl_release(p);
582 *default_acl = NULL;
583 } else {
584 *default_acl = p;
585 }
586 return 0;
587
588 apply_umask:
589 *mode &= ~current_umask();
590 no_acl:
591 *default_acl = NULL;
592 *acl = NULL;
593 return 0;
594 }
595 EXPORT_SYMBOL_GPL(posix_acl_create);
596
597 /**
598 * posix_acl_update_mode - update mode in set_acl
599 *
600 * Update the file mode when setting an ACL: compute the new file permission
601 * bits based on the ACL. In addition, if the ACL is equivalent to the new
602 * file mode, set *acl to NULL to indicate that no ACL should be set.
603 *
604 * As with chmod, clear the setgit bit if the caller is not in the owning group
605 * or capable of CAP_FSETID (see inode_change_ok).
606 *
607 * Called from set_acl inode operations.
608 */
posix_acl_update_mode(struct inode * inode,umode_t * mode_p,struct posix_acl ** acl)609 int posix_acl_update_mode(struct inode *inode, umode_t *mode_p,
610 struct posix_acl **acl)
611 {
612 umode_t mode = inode->i_mode;
613 int error;
614
615 error = posix_acl_equiv_mode(*acl, &mode);
616 if (error < 0)
617 return error;
618 if (error == 0)
619 *acl = NULL;
620 if (!in_group_p(inode->i_gid) &&
621 !capable_wrt_inode_uidgid(inode, CAP_FSETID))
622 mode &= ~S_ISGID;
623 *mode_p = mode;
624 return 0;
625 }
626 EXPORT_SYMBOL(posix_acl_update_mode);
627
628 /*
629 * Fix up the uids and gids in posix acl extended attributes in place.
630 */
posix_acl_fix_xattr_userns(struct user_namespace * to,struct user_namespace * from,void * value,size_t size)631 static void posix_acl_fix_xattr_userns(
632 struct user_namespace *to, struct user_namespace *from,
633 void *value, size_t size)
634 {
635 posix_acl_xattr_header *header = (posix_acl_xattr_header *)value;
636 posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end;
637 int count;
638 kuid_t uid;
639 kgid_t gid;
640
641 if (!value)
642 return;
643 if (size < sizeof(posix_acl_xattr_header))
644 return;
645 if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
646 return;
647
648 count = posix_acl_xattr_count(size);
649 if (count < 0)
650 return;
651 if (count == 0)
652 return;
653
654 for (end = entry + count; entry != end; entry++) {
655 switch(le16_to_cpu(entry->e_tag)) {
656 case ACL_USER:
657 uid = make_kuid(from, le32_to_cpu(entry->e_id));
658 entry->e_id = cpu_to_le32(from_kuid(to, uid));
659 break;
660 case ACL_GROUP:
661 gid = make_kgid(from, le32_to_cpu(entry->e_id));
662 entry->e_id = cpu_to_le32(from_kgid(to, gid));
663 break;
664 default:
665 break;
666 }
667 }
668 }
669
posix_acl_fix_xattr_from_user(void * value,size_t size)670 void posix_acl_fix_xattr_from_user(void *value, size_t size)
671 {
672 struct user_namespace *user_ns = current_user_ns();
673 if (user_ns == &init_user_ns)
674 return;
675 posix_acl_fix_xattr_userns(&init_user_ns, user_ns, value, size);
676 }
677
posix_acl_fix_xattr_to_user(void * value,size_t size)678 void posix_acl_fix_xattr_to_user(void *value, size_t size)
679 {
680 struct user_namespace *user_ns = current_user_ns();
681 if (user_ns == &init_user_ns)
682 return;
683 posix_acl_fix_xattr_userns(user_ns, &init_user_ns, value, size);
684 }
685
686 /*
687 * Convert from extended attribute to in-memory representation.
688 */
689 struct posix_acl *
posix_acl_from_xattr(struct user_namespace * user_ns,const void * value,size_t size)690 posix_acl_from_xattr(struct user_namespace *user_ns,
691 const void *value, size_t size)
692 {
693 posix_acl_xattr_header *header = (posix_acl_xattr_header *)value;
694 posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end;
695 int count;
696 struct posix_acl *acl;
697 struct posix_acl_entry *acl_e;
698
699 if (!value)
700 return NULL;
701 if (size < sizeof(posix_acl_xattr_header))
702 return ERR_PTR(-EINVAL);
703 if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
704 return ERR_PTR(-EOPNOTSUPP);
705
706 count = posix_acl_xattr_count(size);
707 if (count < 0)
708 return ERR_PTR(-EINVAL);
709 if (count == 0)
710 return NULL;
711
712 acl = posix_acl_alloc(count, GFP_NOFS);
713 if (!acl)
714 return ERR_PTR(-ENOMEM);
715 acl_e = acl->a_entries;
716
717 for (end = entry + count; entry != end; acl_e++, entry++) {
718 acl_e->e_tag = le16_to_cpu(entry->e_tag);
719 acl_e->e_perm = le16_to_cpu(entry->e_perm);
720
721 switch(acl_e->e_tag) {
722 case ACL_USER_OBJ:
723 case ACL_GROUP_OBJ:
724 case ACL_MASK:
725 case ACL_OTHER:
726 break;
727
728 case ACL_USER:
729 acl_e->e_uid =
730 make_kuid(user_ns,
731 le32_to_cpu(entry->e_id));
732 if (!uid_valid(acl_e->e_uid))
733 goto fail;
734 break;
735 case ACL_GROUP:
736 acl_e->e_gid =
737 make_kgid(user_ns,
738 le32_to_cpu(entry->e_id));
739 if (!gid_valid(acl_e->e_gid))
740 goto fail;
741 break;
742
743 default:
744 goto fail;
745 }
746 }
747 return acl;
748
749 fail:
750 posix_acl_release(acl);
751 return ERR_PTR(-EINVAL);
752 }
753 EXPORT_SYMBOL (posix_acl_from_xattr);
754
755 /*
756 * Convert from in-memory to extended attribute representation.
757 */
758 int
posix_acl_to_xattr(struct user_namespace * user_ns,const struct posix_acl * acl,void * buffer,size_t size)759 posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl,
760 void *buffer, size_t size)
761 {
762 posix_acl_xattr_header *ext_acl = (posix_acl_xattr_header *)buffer;
763 posix_acl_xattr_entry *ext_entry;
764 int real_size, n;
765
766 real_size = posix_acl_xattr_size(acl->a_count);
767 if (!buffer)
768 return real_size;
769 if (real_size > size)
770 return -ERANGE;
771
772 ext_entry = ext_acl->a_entries;
773 ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);
774
775 for (n=0; n < acl->a_count; n++, ext_entry++) {
776 const struct posix_acl_entry *acl_e = &acl->a_entries[n];
777 ext_entry->e_tag = cpu_to_le16(acl_e->e_tag);
778 ext_entry->e_perm = cpu_to_le16(acl_e->e_perm);
779 switch(acl_e->e_tag) {
780 case ACL_USER:
781 ext_entry->e_id =
782 cpu_to_le32(from_kuid(user_ns, acl_e->e_uid));
783 break;
784 case ACL_GROUP:
785 ext_entry->e_id =
786 cpu_to_le32(from_kgid(user_ns, acl_e->e_gid));
787 break;
788 default:
789 ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID);
790 break;
791 }
792 }
793 return real_size;
794 }
795 EXPORT_SYMBOL (posix_acl_to_xattr);
796
797 static int
posix_acl_xattr_get(struct dentry * dentry,const char * name,void * value,size_t size,int type)798 posix_acl_xattr_get(struct dentry *dentry, const char *name,
799 void *value, size_t size, int type)
800 {
801 struct posix_acl *acl;
802 int error;
803
804 if (!IS_POSIXACL(dentry->d_inode))
805 return -EOPNOTSUPP;
806 if (S_ISLNK(dentry->d_inode->i_mode))
807 return -EOPNOTSUPP;
808
809 acl = get_acl(dentry->d_inode, type);
810 if (IS_ERR(acl))
811 return PTR_ERR(acl);
812 if (acl == NULL)
813 return -ENODATA;
814
815 error = posix_acl_to_xattr(&init_user_ns, acl, value, size);
816 posix_acl_release(acl);
817
818 return error;
819 }
820
821 int
set_posix_acl(struct inode * inode,int type,struct posix_acl * acl)822 set_posix_acl(struct inode *inode, int type, struct posix_acl *acl)
823 {
824 if (!IS_POSIXACL(inode))
825 return -EOPNOTSUPP;
826 if (!inode->i_op->set_acl)
827 return -EOPNOTSUPP;
828
829 if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
830 return acl ? -EACCES : 0;
831 if (!inode_owner_or_capable(inode))
832 return -EPERM;
833
834 if (acl) {
835 int ret = posix_acl_valid(acl);
836 if (ret)
837 return ret;
838 }
839 return inode->i_op->set_acl(inode, acl, type);
840 }
841 EXPORT_SYMBOL(set_posix_acl);
842
843 static int
posix_acl_xattr_set(struct dentry * dentry,const char * name,const void * value,size_t size,int flags,int type)844 posix_acl_xattr_set(struct dentry *dentry, const char *name,
845 const void *value, size_t size, int flags, int type)
846 {
847 struct inode *inode = dentry->d_inode;
848 struct posix_acl *acl = NULL;
849 int ret;
850
851 if (value) {
852 acl = posix_acl_from_xattr(&init_user_ns, value, size);
853 if (IS_ERR(acl))
854 return PTR_ERR(acl);
855 }
856 ret = set_posix_acl(inode, type, acl);
857 posix_acl_release(acl);
858 return ret;
859 }
860
861 static size_t
posix_acl_xattr_list(struct dentry * dentry,char * list,size_t list_size,const char * name,size_t name_len,int type)862 posix_acl_xattr_list(struct dentry *dentry, char *list, size_t list_size,
863 const char *name, size_t name_len, int type)
864 {
865 const char *xname;
866 size_t size;
867
868 if (!IS_POSIXACL(dentry->d_inode))
869 return -EOPNOTSUPP;
870 if (S_ISLNK(dentry->d_inode->i_mode))
871 return -EOPNOTSUPP;
872
873 if (type == ACL_TYPE_ACCESS)
874 xname = POSIX_ACL_XATTR_ACCESS;
875 else
876 xname = POSIX_ACL_XATTR_DEFAULT;
877
878 size = strlen(xname) + 1;
879 if (list && size <= list_size)
880 memcpy(list, xname, size);
881 return size;
882 }
883
884 const struct xattr_handler posix_acl_access_xattr_handler = {
885 .prefix = POSIX_ACL_XATTR_ACCESS,
886 .flags = ACL_TYPE_ACCESS,
887 .list = posix_acl_xattr_list,
888 .get = posix_acl_xattr_get,
889 .set = posix_acl_xattr_set,
890 };
891 EXPORT_SYMBOL_GPL(posix_acl_access_xattr_handler);
892
893 const struct xattr_handler posix_acl_default_xattr_handler = {
894 .prefix = POSIX_ACL_XATTR_DEFAULT,
895 .flags = ACL_TYPE_DEFAULT,
896 .list = posix_acl_xattr_list,
897 .get = posix_acl_xattr_get,
898 .set = posix_acl_xattr_set,
899 };
900 EXPORT_SYMBOL_GPL(posix_acl_default_xattr_handler);
901
simple_set_acl(struct inode * inode,struct posix_acl * acl,int type)902 int simple_set_acl(struct inode *inode, struct posix_acl *acl, int type)
903 {
904 int error;
905
906 if (type == ACL_TYPE_ACCESS) {
907 error = posix_acl_equiv_mode(acl, &inode->i_mode);
908 if (error < 0)
909 return 0;
910 if (error == 0)
911 acl = NULL;
912 }
913
914 inode->i_ctime = CURRENT_TIME;
915 set_cached_acl(inode, type, acl);
916 return 0;
917 }
918
simple_acl_create(struct inode * dir,struct inode * inode)919 int simple_acl_create(struct inode *dir, struct inode *inode)
920 {
921 struct posix_acl *default_acl, *acl;
922 int error;
923
924 error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
925 if (error)
926 return error;
927
928 set_cached_acl(inode, ACL_TYPE_DEFAULT, default_acl);
929 set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
930
931 if (default_acl)
932 posix_acl_release(default_acl);
933 if (acl)
934 posix_acl_release(acl);
935 return 0;
936 }
937