To update vsperf/packet-forwarding configuration files
[kvmfornfv.git] / kernel / fs / posix_acl.c
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
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
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
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
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
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
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
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
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 *
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 *
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
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
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 *
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
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  */
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  */
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
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
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
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
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         struct posix_acl *clone;
551         int ret;
552
553         *acl = NULL;
554         *default_acl = NULL;
555
556         if (S_ISLNK(*mode) || !IS_POSIXACL(dir))
557                 return 0;
558
559         p = get_acl(dir, ACL_TYPE_DEFAULT);
560         if (!p || p == ERR_PTR(-EOPNOTSUPP)) {
561                 *mode &= ~current_umask();
562                 return 0;
563         }
564         if (IS_ERR(p))
565                 return PTR_ERR(p);
566
567         clone = posix_acl_clone(p, GFP_NOFS);
568         if (!clone)
569                 goto no_mem;
570
571         ret = posix_acl_create_masq(clone, mode);
572         if (ret < 0)
573                 goto no_mem_clone;
574
575         if (ret == 0)
576                 posix_acl_release(clone);
577         else
578                 *acl = clone;
579
580         if (!S_ISDIR(*mode))
581                 posix_acl_release(p);
582         else
583                 *default_acl = p;
584
585         return 0;
586
587 no_mem_clone:
588         posix_acl_release(clone);
589 no_mem:
590         posix_acl_release(p);
591         return -ENOMEM;
592 }
593 EXPORT_SYMBOL_GPL(posix_acl_create);
594
595 /**
596  * posix_acl_update_mode  -  update mode in set_acl
597  *
598  * Update the file mode when setting an ACL: compute the new file permission
599  * bits based on the ACL.  In addition, if the ACL is equivalent to the new
600  * file mode, set *acl to NULL to indicate that no ACL should be set.
601  *
602  * As with chmod, clear the setgit bit if the caller is not in the owning group
603  * or capable of CAP_FSETID (see inode_change_ok).
604  *
605  * Called from set_acl inode operations.
606  */
607 int posix_acl_update_mode(struct inode *inode, umode_t *mode_p,
608                           struct posix_acl **acl)
609 {
610         umode_t mode = inode->i_mode;
611         int error;
612
613         error = posix_acl_equiv_mode(*acl, &mode);
614         if (error < 0)
615                 return error;
616         if (error == 0)
617                 *acl = NULL;
618         if (!in_group_p(inode->i_gid) &&
619             !capable_wrt_inode_uidgid(inode, CAP_FSETID))
620                 mode &= ~S_ISGID;
621         *mode_p = mode;
622         return 0;
623 }
624 EXPORT_SYMBOL(posix_acl_update_mode);
625
626 /*
627  * Fix up the uids and gids in posix acl extended attributes in place.
628  */
629 static void posix_acl_fix_xattr_userns(
630         struct user_namespace *to, struct user_namespace *from,
631         void *value, size_t size)
632 {
633         posix_acl_xattr_header *header = (posix_acl_xattr_header *)value;
634         posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end;
635         int count;
636         kuid_t uid;
637         kgid_t gid;
638
639         if (!value)
640                 return;
641         if (size < sizeof(posix_acl_xattr_header))
642                 return;
643         if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
644                 return;
645
646         count = posix_acl_xattr_count(size);
647         if (count < 0)
648                 return;
649         if (count == 0)
650                 return;
651
652         for (end = entry + count; entry != end; entry++) {
653                 switch(le16_to_cpu(entry->e_tag)) {
654                 case ACL_USER:
655                         uid = make_kuid(from, le32_to_cpu(entry->e_id));
656                         entry->e_id = cpu_to_le32(from_kuid(to, uid));
657                         break;
658                 case ACL_GROUP:
659                         gid = make_kgid(from, le32_to_cpu(entry->e_id));
660                         entry->e_id = cpu_to_le32(from_kgid(to, gid));
661                         break;
662                 default:
663                         break;
664                 }
665         }
666 }
667
668 void posix_acl_fix_xattr_from_user(void *value, size_t size)
669 {
670         struct user_namespace *user_ns = current_user_ns();
671         if (user_ns == &init_user_ns)
672                 return;
673         posix_acl_fix_xattr_userns(&init_user_ns, user_ns, value, size);
674 }
675
676 void posix_acl_fix_xattr_to_user(void *value, size_t size)
677 {
678         struct user_namespace *user_ns = current_user_ns();
679         if (user_ns == &init_user_ns)
680                 return;
681         posix_acl_fix_xattr_userns(user_ns, &init_user_ns, value, size);
682 }
683
684 /*
685  * Convert from extended attribute to in-memory representation.
686  */
687 struct posix_acl *
688 posix_acl_from_xattr(struct user_namespace *user_ns,
689                      const void *value, size_t size)
690 {
691         posix_acl_xattr_header *header = (posix_acl_xattr_header *)value;
692         posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end;
693         int count;
694         struct posix_acl *acl;
695         struct posix_acl_entry *acl_e;
696
697         if (!value)
698                 return NULL;
699         if (size < sizeof(posix_acl_xattr_header))
700                  return ERR_PTR(-EINVAL);
701         if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
702                 return ERR_PTR(-EOPNOTSUPP);
703
704         count = posix_acl_xattr_count(size);
705         if (count < 0)
706                 return ERR_PTR(-EINVAL);
707         if (count == 0)
708                 return NULL;
709         
710         acl = posix_acl_alloc(count, GFP_NOFS);
711         if (!acl)
712                 return ERR_PTR(-ENOMEM);
713         acl_e = acl->a_entries;
714         
715         for (end = entry + count; entry != end; acl_e++, entry++) {
716                 acl_e->e_tag  = le16_to_cpu(entry->e_tag);
717                 acl_e->e_perm = le16_to_cpu(entry->e_perm);
718
719                 switch(acl_e->e_tag) {
720                         case ACL_USER_OBJ:
721                         case ACL_GROUP_OBJ:
722                         case ACL_MASK:
723                         case ACL_OTHER:
724                                 break;
725
726                         case ACL_USER:
727                                 acl_e->e_uid =
728                                         make_kuid(user_ns,
729                                                   le32_to_cpu(entry->e_id));
730                                 if (!uid_valid(acl_e->e_uid))
731                                         goto fail;
732                                 break;
733                         case ACL_GROUP:
734                                 acl_e->e_gid =
735                                         make_kgid(user_ns,
736                                                   le32_to_cpu(entry->e_id));
737                                 if (!gid_valid(acl_e->e_gid))
738                                         goto fail;
739                                 break;
740
741                         default:
742                                 goto fail;
743                 }
744         }
745         return acl;
746
747 fail:
748         posix_acl_release(acl);
749         return ERR_PTR(-EINVAL);
750 }
751 EXPORT_SYMBOL (posix_acl_from_xattr);
752
753 /*
754  * Convert from in-memory to extended attribute representation.
755  */
756 int
757 posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl,
758                    void *buffer, size_t size)
759 {
760         posix_acl_xattr_header *ext_acl = (posix_acl_xattr_header *)buffer;
761         posix_acl_xattr_entry *ext_entry;
762         int real_size, n;
763
764         real_size = posix_acl_xattr_size(acl->a_count);
765         if (!buffer)
766                 return real_size;
767         if (real_size > size)
768                 return -ERANGE;
769
770         ext_entry = ext_acl->a_entries;
771         ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);
772
773         for (n=0; n < acl->a_count; n++, ext_entry++) {
774                 const struct posix_acl_entry *acl_e = &acl->a_entries[n];
775                 ext_entry->e_tag  = cpu_to_le16(acl_e->e_tag);
776                 ext_entry->e_perm = cpu_to_le16(acl_e->e_perm);
777                 switch(acl_e->e_tag) {
778                 case ACL_USER:
779                         ext_entry->e_id =
780                                 cpu_to_le32(from_kuid(user_ns, acl_e->e_uid));
781                         break;
782                 case ACL_GROUP:
783                         ext_entry->e_id =
784                                 cpu_to_le32(from_kgid(user_ns, acl_e->e_gid));
785                         break;
786                 default:
787                         ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID);
788                         break;
789                 }
790         }
791         return real_size;
792 }
793 EXPORT_SYMBOL (posix_acl_to_xattr);
794
795 static int
796 posix_acl_xattr_get(const struct xattr_handler *handler,
797                     struct dentry *dentry, const char *name,
798                     void *value, size_t size)
799 {
800         struct posix_acl *acl;
801         int error;
802
803         if (strcmp(name, "") != 0)
804                 return -EINVAL;
805         if (!IS_POSIXACL(d_backing_inode(dentry)))
806                 return -EOPNOTSUPP;
807         if (d_is_symlink(dentry))
808                 return -EOPNOTSUPP;
809
810         acl = get_acl(d_backing_inode(dentry), handler->flags);
811         if (IS_ERR(acl))
812                 return PTR_ERR(acl);
813         if (acl == NULL)
814                 return -ENODATA;
815
816         error = posix_acl_to_xattr(&init_user_ns, acl, value, size);
817         posix_acl_release(acl);
818
819         return error;
820 }
821
822 int
823 set_posix_acl(struct inode *inode, int type, struct posix_acl *acl)
824 {
825         if (!IS_POSIXACL(inode))
826                 return -EOPNOTSUPP;
827         if (!inode->i_op->set_acl)
828                 return -EOPNOTSUPP;
829
830         if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
831                 return acl ? -EACCES : 0;
832         if (!inode_owner_or_capable(inode))
833                 return -EPERM;
834
835         if (acl) {
836                 int ret = posix_acl_valid(acl);
837                 if (ret)
838                         return ret;
839         }
840         return inode->i_op->set_acl(inode, acl, type);
841 }
842 EXPORT_SYMBOL(set_posix_acl);
843
844 static int
845 posix_acl_xattr_set(const struct xattr_handler *handler,
846                     struct dentry *dentry, const char *name,
847                     const void *value, size_t size, int flags)
848 {
849         struct inode *inode = d_backing_inode(dentry);
850         struct posix_acl *acl = NULL;
851         int ret;
852
853         if (strcmp(name, "") != 0)
854                 return -EINVAL;
855
856         if (value) {
857                 acl = posix_acl_from_xattr(&init_user_ns, value, size);
858                 if (IS_ERR(acl))
859                         return PTR_ERR(acl);
860         }
861         ret = set_posix_acl(inode, handler->flags, acl);
862         posix_acl_release(acl);
863         return ret;
864 }
865
866 static size_t
867 posix_acl_xattr_list(const struct xattr_handler *handler,
868                      struct dentry *dentry, char *list, size_t list_size,
869                      const char *name, size_t name_len)
870 {
871         const char *xname = handler->prefix;
872         size_t size;
873
874         if (!IS_POSIXACL(d_backing_inode(dentry)))
875                 return 0;
876
877         size = strlen(xname) + 1;
878         if (list && size <= list_size)
879                 memcpy(list, xname, size);
880         return size;
881 }
882
883 const struct xattr_handler posix_acl_access_xattr_handler = {
884         .prefix = POSIX_ACL_XATTR_ACCESS,
885         .flags = ACL_TYPE_ACCESS,
886         .list = posix_acl_xattr_list,
887         .get = posix_acl_xattr_get,
888         .set = posix_acl_xattr_set,
889 };
890 EXPORT_SYMBOL_GPL(posix_acl_access_xattr_handler);
891
892 const struct xattr_handler posix_acl_default_xattr_handler = {
893         .prefix = POSIX_ACL_XATTR_DEFAULT,
894         .flags = ACL_TYPE_DEFAULT,
895         .list = posix_acl_xattr_list,
896         .get = posix_acl_xattr_get,
897         .set = posix_acl_xattr_set,
898 };
899 EXPORT_SYMBOL_GPL(posix_acl_default_xattr_handler);
900
901 int simple_set_acl(struct inode *inode, struct posix_acl *acl, int type)
902 {
903         int error;
904
905         if (type == ACL_TYPE_ACCESS) {
906                 error = posix_acl_update_mode(inode,
907                                 &inode->i_mode, &acl);
908                 if (error)
909                         return error;
910         }
911
912         inode->i_ctime = CURRENT_TIME;
913         set_cached_acl(inode, type, acl);
914         return 0;
915 }
916
917 int simple_acl_create(struct inode *dir, struct inode *inode)
918 {
919         struct posix_acl *default_acl, *acl;
920         int error;
921
922         error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
923         if (error)
924                 return error;
925
926         set_cached_acl(inode, ACL_TYPE_DEFAULT, default_acl);
927         set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
928
929         if (default_acl)
930                 posix_acl_release(default_acl);
931         if (acl)
932                 posix_acl_release(acl);
933         return 0;
934 }