blob: 9e363e41dacc8c2ebc007661a598c01e84da45c9 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Christoph Hellwig5c8ebd52013-12-20 05:16:37 -08002 * Copyright (C) 2002,2003 by Andreas Gruenbacher <a.gruenbacher@computer.org>
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 *
Christoph Hellwig5c8ebd52013-12-20 05:16:37 -08004 * Fixes from William Schumacher incorporated on 15 March 2001.
5 * (Reported by Charles Bertsch, <CBertsch@microtest.com>).
Linus Torvalds1da177e2005-04-16 15:20:36 -07006 */
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>
Arun Sharma600634972011-07-26 16:09:06 -070015#include <linux/atomic.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <linux/fs.h>
17#include <linux/sched.h>
18#include <linux/posix_acl.h>
Christoph Hellwig5c8ebd52013-12-20 05:16:37 -080019#include <linux/posix_acl_xattr.h>
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -080020#include <linux/xattr.h>
Paul Gortmaker630d9c42011-11-16 23:57:37 -050021#include <linux/export.h>
Christoph Hellwig5c8ebd52013-12-20 05:16:37 -080022#include <linux/user_namespace.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070023
Andrew Morton0afaa122014-01-21 15:48:42 -080024struct 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);
Linus Torvalds1da177e2005-04-16 15:20:36 -070098
Christoph Hellwig2982baa2013-12-20 05:16:38 -080099struct 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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126/*
Chuck Leverf61f6da2011-01-21 03:05:38 +0000127 * 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}
Andrew Morton0afaa122014-01-21 15:48:42 -0800135EXPORT_SYMBOL(posix_acl_init);
Chuck Leverf61f6da2011-01-21 03:05:38 +0000136
137/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138 * Allocate a new ACL with the specified number of entries.
139 */
140struct posix_acl *
Al Virodd0fc662005-10-07 07:46:04 +0100141posix_acl_alloc(int count, gfp_t flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142{
143 const size_t size = sizeof(struct posix_acl) +
144 count * sizeof(struct posix_acl_entry);
145 struct posix_acl *acl = kmalloc(size, flags);
Chuck Leverf61f6da2011-01-21 03:05:38 +0000146 if (acl)
147 posix_acl_init(acl, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148 return acl;
149}
Andrew Morton0afaa122014-01-21 15:48:42 -0800150EXPORT_SYMBOL(posix_acl_alloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151
152/*
153 * Clone an ACL.
154 */
Al Viroedde8542011-07-23 03:27:37 -0400155static struct posix_acl *
Al Virodd0fc662005-10-07 07:46:04 +0100156posix_acl_clone(const struct posix_acl *acl, gfp_t flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157{
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);
Alexey Dobriyan52978be2006-09-30 23:27:21 -0700163 clone = kmemdup(acl, size, flags);
164 if (clone)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165 atomic_set(&clone->a_refcount, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 }
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;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178 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) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186 state = ACL_USER;
187 break;
188 }
189 return -EINVAL;
190
191 case ACL_USER:
192 if (state != ACL_USER)
193 return -EINVAL;
Eric W. Biederman2f6f0652012-02-07 18:52:57 -0800194 if (!uid_valid(pa->e_uid))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196 needs_mask = 1;
197 break;
198
199 case ACL_GROUP_OBJ:
200 if (state == ACL_USER) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 state = ACL_GROUP;
202 break;
203 }
204 return -EINVAL;
205
206 case ACL_GROUP:
207 if (state != ACL_GROUP)
208 return -EINVAL;
Eric W. Biederman2f6f0652012-02-07 18:52:57 -0800209 if (!gid_valid(pa->e_gid))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211 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}
Andrew Morton0afaa122014-01-21 15:48:42 -0800236EXPORT_SYMBOL(posix_acl_valid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237
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
Al Virod6952122011-07-23 18:56:36 -0400243posix_acl_equiv_mode(const struct posix_acl *acl, umode_t *mode_p)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244{
245 const struct posix_acl_entry *pa, *pe;
Al Virod6952122011-07-23 18:56:36 -0400246 umode_t mode = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247 int not_equiv = 0;
248
249 FOREACH_ACL_ENTRY(pa, acl, pe) {
250 switch (pa->e_tag) {
251 case ACL_USER_OBJ:
252 mode |= (pa->e_perm & S_IRWXO) << 6;
253 break;
254 case ACL_GROUP_OBJ:
255 mode |= (pa->e_perm & S_IRWXO) << 3;
256 break;
257 case ACL_OTHER:
258 mode |= pa->e_perm & S_IRWXO;
259 break;
260 case ACL_MASK:
261 mode = (mode & ~S_IRWXG) |
262 ((pa->e_perm & S_IRWXO) << 3);
263 not_equiv = 1;
264 break;
265 case ACL_USER:
266 case ACL_GROUP:
267 not_equiv = 1;
268 break;
269 default:
270 return -EINVAL;
271 }
272 }
273 if (mode_p)
274 *mode_p = (*mode_p & ~S_IRWXUGO) | mode;
275 return not_equiv;
276}
Andrew Morton0afaa122014-01-21 15:48:42 -0800277EXPORT_SYMBOL(posix_acl_equiv_mode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278
279/*
280 * Create an ACL representing the file mode permission bits of an inode.
281 */
282struct posix_acl *
Al Viro3a5fba12011-07-23 19:01:48 -0400283posix_acl_from_mode(umode_t mode, gfp_t flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284{
285 struct posix_acl *acl = posix_acl_alloc(3, flags);
286 if (!acl)
287 return ERR_PTR(-ENOMEM);
288
289 acl->a_entries[0].e_tag = ACL_USER_OBJ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290 acl->a_entries[0].e_perm = (mode & S_IRWXU) >> 6;
291
292 acl->a_entries[1].e_tag = ACL_GROUP_OBJ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293 acl->a_entries[1].e_perm = (mode & S_IRWXG) >> 3;
294
295 acl->a_entries[2].e_tag = ACL_OTHER;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296 acl->a_entries[2].e_perm = (mode & S_IRWXO);
297 return acl;
298}
Andrew Morton0afaa122014-01-21 15:48:42 -0800299EXPORT_SYMBOL(posix_acl_from_mode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300
301/*
302 * Return 0 if current is granted want access to the inode
303 * by the acl. Returns -E... otherwise.
304 */
305int
306posix_acl_permission(struct inode *inode, const struct posix_acl *acl, int want)
307{
308 const struct posix_acl_entry *pa, *pe, *mask_obj;
309 int found = 0;
310
Andreas Gruenbacherd124b602011-10-23 23:13:32 +0530311 want &= MAY_READ | MAY_WRITE | MAY_EXEC | MAY_NOT_BLOCK;
312
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313 FOREACH_ACL_ENTRY(pa, acl, pe) {
314 switch(pa->e_tag) {
315 case ACL_USER_OBJ:
316 /* (May have been checked already) */
Eric W. Biederman2f6f0652012-02-07 18:52:57 -0800317 if (uid_eq(inode->i_uid, current_fsuid()))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318 goto check_perm;
319 break;
320 case ACL_USER:
Eric W. Biederman2f6f0652012-02-07 18:52:57 -0800321 if (uid_eq(pa->e_uid, current_fsuid()))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322 goto mask;
323 break;
324 case ACL_GROUP_OBJ:
325 if (in_group_p(inode->i_gid)) {
326 found = 1;
327 if ((pa->e_perm & want) == want)
328 goto mask;
329 }
330 break;
331 case ACL_GROUP:
Eric W. Biederman2f6f0652012-02-07 18:52:57 -0800332 if (in_group_p(pa->e_gid)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333 found = 1;
334 if ((pa->e_perm & want) == want)
335 goto mask;
336 }
337 break;
338 case ACL_MASK:
339 break;
340 case ACL_OTHER:
341 if (found)
342 return -EACCES;
343 else
344 goto check_perm;
345 default:
346 return -EIO;
347 }
348 }
349 return -EIO;
350
351mask:
352 for (mask_obj = pa+1; mask_obj != pe; mask_obj++) {
353 if (mask_obj->e_tag == ACL_MASK) {
354 if ((pa->e_perm & mask_obj->e_perm & want) == want)
355 return 0;
356 return -EACCES;
357 }
358 }
359
360check_perm:
361 if ((pa->e_perm & want) == want)
362 return 0;
363 return -EACCES;
364}
365
366/*
367 * Modify acl when creating a new inode. The caller must ensure the acl is
368 * only referenced once.
369 *
370 * mode_p initially must contain the mode parameter to the open() / creat()
371 * system calls. All permissions that are not granted by the acl are removed.
372 * The permissions in the acl are changed to reflect the mode_p parameter.
373 */
Al Virod3fb6122011-07-23 18:37:50 -0400374static int posix_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375{
376 struct posix_acl_entry *pa, *pe;
377 struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
Al Virod3fb6122011-07-23 18:37:50 -0400378 umode_t mode = *mode_p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379 int not_equiv = 0;
380
381 /* assert(atomic_read(acl->a_refcount) == 1); */
382
383 FOREACH_ACL_ENTRY(pa, acl, pe) {
384 switch(pa->e_tag) {
385 case ACL_USER_OBJ:
386 pa->e_perm &= (mode >> 6) | ~S_IRWXO;
387 mode &= (pa->e_perm << 6) | ~S_IRWXU;
388 break;
389
390 case ACL_USER:
391 case ACL_GROUP:
392 not_equiv = 1;
393 break;
394
395 case ACL_GROUP_OBJ:
396 group_obj = pa;
397 break;
398
399 case ACL_OTHER:
400 pa->e_perm &= mode | ~S_IRWXO;
401 mode &= pa->e_perm | ~S_IRWXO;
402 break;
403
404 case ACL_MASK:
405 mask_obj = pa;
406 not_equiv = 1;
407 break;
408
409 default:
410 return -EIO;
411 }
412 }
413
414 if (mask_obj) {
415 mask_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
416 mode &= (mask_obj->e_perm << 3) | ~S_IRWXG;
417 } else {
418 if (!group_obj)
419 return -EIO;
420 group_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
421 mode &= (group_obj->e_perm << 3) | ~S_IRWXG;
422 }
423
424 *mode_p = (*mode_p & ~S_IRWXUGO) | mode;
425 return not_equiv;
426}
427
428/*
429 * Modify the ACL for the chmod syscall.
430 */
Christoph Hellwig5bf32582013-12-20 05:16:41 -0800431static int __posix_acl_chmod_masq(struct posix_acl *acl, umode_t mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432{
433 struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
434 struct posix_acl_entry *pa, *pe;
435
436 /* assert(atomic_read(acl->a_refcount) == 1); */
437
438 FOREACH_ACL_ENTRY(pa, acl, pe) {
439 switch(pa->e_tag) {
440 case ACL_USER_OBJ:
441 pa->e_perm = (mode & S_IRWXU) >> 6;
442 break;
443
444 case ACL_USER:
445 case ACL_GROUP:
446 break;
447
448 case ACL_GROUP_OBJ:
449 group_obj = pa;
450 break;
451
452 case ACL_MASK:
453 mask_obj = pa;
454 break;
455
456 case ACL_OTHER:
457 pa->e_perm = (mode & S_IRWXO);
458 break;
459
460 default:
461 return -EIO;
462 }
463 }
464
465 if (mask_obj) {
466 mask_obj->e_perm = (mode & S_IRWXG) >> 3;
467 } else {
468 if (!group_obj)
469 return -EIO;
470 group_obj->e_perm = (mode & S_IRWXG) >> 3;
471 }
472
473 return 0;
474}
Al Virobc26ab52011-07-23 00:18:02 -0400475
476int
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800477__posix_acl_create(struct posix_acl **acl, gfp_t gfp, umode_t *mode_p)
Al Viro826cae22011-07-23 03:10:32 -0400478{
479 struct posix_acl *clone = posix_acl_clone(*acl, gfp);
480 int err = -ENOMEM;
481 if (clone) {
482 err = posix_acl_create_masq(clone, mode_p);
483 if (err < 0) {
484 posix_acl_release(clone);
485 clone = NULL;
486 }
487 }
488 posix_acl_release(*acl);
489 *acl = clone;
490 return err;
491}
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800492EXPORT_SYMBOL(__posix_acl_create);
Al Viro826cae22011-07-23 03:10:32 -0400493
494int
Christoph Hellwig5bf32582013-12-20 05:16:41 -0800495__posix_acl_chmod(struct posix_acl **acl, gfp_t gfp, umode_t mode)
Al Virobc26ab52011-07-23 00:18:02 -0400496{
497 struct posix_acl *clone = posix_acl_clone(*acl, gfp);
498 int err = -ENOMEM;
499 if (clone) {
Christoph Hellwig5bf32582013-12-20 05:16:41 -0800500 err = __posix_acl_chmod_masq(clone, mode);
Al Virobc26ab52011-07-23 00:18:02 -0400501 if (err) {
502 posix_acl_release(clone);
503 clone = NULL;
504 }
505 }
506 posix_acl_release(*acl);
507 *acl = clone;
508 return err;
509}
Christoph Hellwig5bf32582013-12-20 05:16:41 -0800510EXPORT_SYMBOL(__posix_acl_chmod);
511
512int
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800513posix_acl_chmod(struct inode *inode, umode_t mode)
Christoph Hellwig5bf32582013-12-20 05:16:41 -0800514{
515 struct posix_acl *acl;
516 int ret = 0;
517
518 if (!IS_POSIXACL(inode))
519 return 0;
520 if (!inode->i_op->set_acl)
521 return -EOPNOTSUPP;
522
523 acl = get_acl(inode, ACL_TYPE_ACCESS);
Trond Myklebust789b6632014-01-31 14:25:19 -0500524 if (IS_ERR_OR_NULL(acl)) {
525 if (acl == ERR_PTR(-EOPNOTSUPP))
526 return 0;
Christoph Hellwig5bf32582013-12-20 05:16:41 -0800527 return PTR_ERR(acl);
Trond Myklebust789b6632014-01-31 14:25:19 -0500528 }
Christoph Hellwig5bf32582013-12-20 05:16:41 -0800529
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800530 ret = __posix_acl_chmod(&acl, GFP_KERNEL, mode);
Christoph Hellwig5bf32582013-12-20 05:16:41 -0800531 if (ret)
532 return ret;
533 ret = inode->i_op->set_acl(inode, acl, ACL_TYPE_ACCESS);
534 posix_acl_release(acl);
535 return ret;
536}
Al Virobc26ab52011-07-23 00:18:02 -0400537EXPORT_SYMBOL(posix_acl_chmod);
Christoph Hellwig5c8ebd52013-12-20 05:16:37 -0800538
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800539int
540posix_acl_create(struct inode *dir, umode_t *mode,
541 struct posix_acl **default_acl, struct posix_acl **acl)
542{
543 struct posix_acl *p;
544 int ret;
545
546 if (S_ISLNK(*mode) || !IS_POSIXACL(dir))
547 goto no_acl;
548
549 p = get_acl(dir, ACL_TYPE_DEFAULT);
Trond Myklebust789b6632014-01-31 14:25:19 -0500550 if (IS_ERR(p)) {
551 if (p == ERR_PTR(-EOPNOTSUPP))
552 goto apply_umask;
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800553 return PTR_ERR(p);
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800554 }
555
Trond Myklebust789b6632014-01-31 14:25:19 -0500556 if (!p)
557 goto apply_umask;
558
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800559 *acl = posix_acl_clone(p, GFP_NOFS);
560 if (!*acl)
561 return -ENOMEM;
562
563 ret = posix_acl_create_masq(*acl, mode);
564 if (ret < 0) {
565 posix_acl_release(*acl);
566 return -ENOMEM;
567 }
568
569 if (ret == 0) {
570 posix_acl_release(*acl);
571 *acl = NULL;
572 }
573
574 if (!S_ISDIR(*mode)) {
575 posix_acl_release(p);
576 *default_acl = NULL;
577 } else {
578 *default_acl = p;
579 }
580 return 0;
581
Trond Myklebust789b6632014-01-31 14:25:19 -0500582apply_umask:
583 *mode &= ~current_umask();
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800584no_acl:
585 *default_acl = NULL;
586 *acl = NULL;
587 return 0;
588}
589EXPORT_SYMBOL_GPL(posix_acl_create);
590
Christoph Hellwig5c8ebd52013-12-20 05:16:37 -0800591/*
592 * Fix up the uids and gids in posix acl extended attributes in place.
593 */
594static void posix_acl_fix_xattr_userns(
595 struct user_namespace *to, struct user_namespace *from,
596 void *value, size_t size)
597{
598 posix_acl_xattr_header *header = (posix_acl_xattr_header *)value;
599 posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end;
600 int count;
601 kuid_t uid;
602 kgid_t gid;
603
604 if (!value)
605 return;
606 if (size < sizeof(posix_acl_xattr_header))
607 return;
608 if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
609 return;
610
611 count = posix_acl_xattr_count(size);
612 if (count < 0)
613 return;
614 if (count == 0)
615 return;
616
617 for (end = entry + count; entry != end; entry++) {
618 switch(le16_to_cpu(entry->e_tag)) {
619 case ACL_USER:
620 uid = make_kuid(from, le32_to_cpu(entry->e_id));
621 entry->e_id = cpu_to_le32(from_kuid(to, uid));
622 break;
623 case ACL_GROUP:
624 gid = make_kgid(from, le32_to_cpu(entry->e_id));
625 entry->e_id = cpu_to_le32(from_kgid(to, gid));
626 break;
627 default:
628 break;
629 }
630 }
631}
632
633void posix_acl_fix_xattr_from_user(void *value, size_t size)
634{
635 struct user_namespace *user_ns = current_user_ns();
636 if (user_ns == &init_user_ns)
637 return;
638 posix_acl_fix_xattr_userns(&init_user_ns, user_ns, value, size);
639}
640
641void posix_acl_fix_xattr_to_user(void *value, size_t size)
642{
643 struct user_namespace *user_ns = current_user_ns();
644 if (user_ns == &init_user_ns)
645 return;
646 posix_acl_fix_xattr_userns(user_ns, &init_user_ns, value, size);
647}
648
649/*
650 * Convert from extended attribute to in-memory representation.
651 */
652struct posix_acl *
653posix_acl_from_xattr(struct user_namespace *user_ns,
654 const void *value, size_t size)
655{
656 posix_acl_xattr_header *header = (posix_acl_xattr_header *)value;
657 posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end;
658 int count;
659 struct posix_acl *acl;
660 struct posix_acl_entry *acl_e;
661
662 if (!value)
663 return NULL;
664 if (size < sizeof(posix_acl_xattr_header))
665 return ERR_PTR(-EINVAL);
666 if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
667 return ERR_PTR(-EOPNOTSUPP);
668
669 count = posix_acl_xattr_count(size);
670 if (count < 0)
671 return ERR_PTR(-EINVAL);
672 if (count == 0)
673 return NULL;
674
675 acl = posix_acl_alloc(count, GFP_NOFS);
676 if (!acl)
677 return ERR_PTR(-ENOMEM);
678 acl_e = acl->a_entries;
679
680 for (end = entry + count; entry != end; acl_e++, entry++) {
681 acl_e->e_tag = le16_to_cpu(entry->e_tag);
682 acl_e->e_perm = le16_to_cpu(entry->e_perm);
683
684 switch(acl_e->e_tag) {
685 case ACL_USER_OBJ:
686 case ACL_GROUP_OBJ:
687 case ACL_MASK:
688 case ACL_OTHER:
689 break;
690
691 case ACL_USER:
692 acl_e->e_uid =
693 make_kuid(user_ns,
694 le32_to_cpu(entry->e_id));
695 if (!uid_valid(acl_e->e_uid))
696 goto fail;
697 break;
698 case ACL_GROUP:
699 acl_e->e_gid =
700 make_kgid(user_ns,
701 le32_to_cpu(entry->e_id));
702 if (!gid_valid(acl_e->e_gid))
703 goto fail;
704 break;
705
706 default:
707 goto fail;
708 }
709 }
710 return acl;
711
712fail:
713 posix_acl_release(acl);
714 return ERR_PTR(-EINVAL);
715}
716EXPORT_SYMBOL (posix_acl_from_xattr);
717
718/*
719 * Convert from in-memory to extended attribute representation.
720 */
721int
722posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl,
723 void *buffer, size_t size)
724{
725 posix_acl_xattr_header *ext_acl = (posix_acl_xattr_header *)buffer;
Dan Carpenter47ba9732014-02-14 12:05:49 +0300726 posix_acl_xattr_entry *ext_entry;
Christoph Hellwig5c8ebd52013-12-20 05:16:37 -0800727 int real_size, n;
728
729 real_size = posix_acl_xattr_size(acl->a_count);
730 if (!buffer)
731 return real_size;
732 if (real_size > size)
733 return -ERANGE;
Dan Carpenter47ba9732014-02-14 12:05:49 +0300734
735 ext_entry = ext_acl->a_entries;
Christoph Hellwig5c8ebd52013-12-20 05:16:37 -0800736 ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);
737
738 for (n=0; n < acl->a_count; n++, ext_entry++) {
739 const struct posix_acl_entry *acl_e = &acl->a_entries[n];
740 ext_entry->e_tag = cpu_to_le16(acl_e->e_tag);
741 ext_entry->e_perm = cpu_to_le16(acl_e->e_perm);
742 switch(acl_e->e_tag) {
743 case ACL_USER:
744 ext_entry->e_id =
745 cpu_to_le32(from_kuid(user_ns, acl_e->e_uid));
746 break;
747 case ACL_GROUP:
748 ext_entry->e_id =
749 cpu_to_le32(from_kgid(user_ns, acl_e->e_gid));
750 break;
751 default:
752 ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID);
753 break;
754 }
755 }
756 return real_size;
757}
758EXPORT_SYMBOL (posix_acl_to_xattr);
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800759
760static int
761posix_acl_xattr_get(struct dentry *dentry, const char *name,
762 void *value, size_t size, int type)
763{
764 struct posix_acl *acl;
765 int error;
766
767 if (!IS_POSIXACL(dentry->d_inode))
768 return -EOPNOTSUPP;
769 if (S_ISLNK(dentry->d_inode->i_mode))
770 return -EOPNOTSUPP;
771
772 acl = get_acl(dentry->d_inode, type);
773 if (IS_ERR(acl))
774 return PTR_ERR(acl);
775 if (acl == NULL)
776 return -ENODATA;
777
778 error = posix_acl_to_xattr(&init_user_ns, acl, value, size);
779 posix_acl_release(acl);
780
781 return error;
782}
783
784static int
785posix_acl_xattr_set(struct dentry *dentry, const char *name,
786 const void *value, size_t size, int flags, int type)
787{
788 struct inode *inode = dentry->d_inode;
789 struct posix_acl *acl = NULL;
790 int ret;
791
792 if (!IS_POSIXACL(inode))
793 return -EOPNOTSUPP;
794 if (!inode->i_op->set_acl)
795 return -EOPNOTSUPP;
796
797 if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
798 return value ? -EACCES : 0;
799 if (!inode_owner_or_capable(inode))
800 return -EPERM;
801
802 if (value) {
803 acl = posix_acl_from_xattr(&init_user_ns, value, size);
804 if (IS_ERR(acl))
805 return PTR_ERR(acl);
806
807 if (acl) {
808 ret = posix_acl_valid(acl);
809 if (ret)
810 goto out;
811 }
812 }
813
814 ret = inode->i_op->set_acl(inode, acl, type);
815out:
816 posix_acl_release(acl);
817 return ret;
818}
819
820static size_t
821posix_acl_xattr_list(struct dentry *dentry, char *list, size_t list_size,
822 const char *name, size_t name_len, int type)
823{
824 const char *xname;
825 size_t size;
826
827 if (!IS_POSIXACL(dentry->d_inode))
828 return -EOPNOTSUPP;
829 if (S_ISLNK(dentry->d_inode->i_mode))
830 return -EOPNOTSUPP;
831
832 if (type == ACL_TYPE_ACCESS)
833 xname = POSIX_ACL_XATTR_ACCESS;
834 else
835 xname = POSIX_ACL_XATTR_DEFAULT;
836
837 size = strlen(xname) + 1;
838 if (list && size <= list_size)
839 memcpy(list, xname, size);
840 return size;
841}
842
843const struct xattr_handler posix_acl_access_xattr_handler = {
844 .prefix = POSIX_ACL_XATTR_ACCESS,
845 .flags = ACL_TYPE_ACCESS,
846 .list = posix_acl_xattr_list,
847 .get = posix_acl_xattr_get,
848 .set = posix_acl_xattr_set,
849};
850EXPORT_SYMBOL_GPL(posix_acl_access_xattr_handler);
851
852const struct xattr_handler posix_acl_default_xattr_handler = {
853 .prefix = POSIX_ACL_XATTR_DEFAULT,
854 .flags = ACL_TYPE_DEFAULT,
855 .list = posix_acl_xattr_list,
856 .get = posix_acl_xattr_get,
857 .set = posix_acl_xattr_set,
858};
859EXPORT_SYMBOL_GPL(posix_acl_default_xattr_handler);
Christoph Hellwigfeda8212013-12-20 05:16:54 -0800860
861int simple_set_acl(struct inode *inode, struct posix_acl *acl, int type)
862{
863 int error;
864
865 if (type == ACL_TYPE_ACCESS) {
866 error = posix_acl_equiv_mode(acl, &inode->i_mode);
867 if (error < 0)
868 return 0;
869 if (error == 0)
870 acl = NULL;
871 }
872
873 inode->i_ctime = CURRENT_TIME;
874 set_cached_acl(inode, type, acl);
875 return 0;
876}
877
878int simple_acl_create(struct inode *dir, struct inode *inode)
879{
880 struct posix_acl *default_acl, *acl;
881 int error;
882
883 error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
884 if (error)
885 return error;
886
887 set_cached_acl(inode, ACL_TYPE_DEFAULT, default_acl);
888 set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
889
890 if (default_acl)
891 posix_acl_release(default_acl);
892 if (acl)
893 posix_acl_release(acl);
894 return 0;
895}