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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>
Ingo Molnar5b825c32017-02-02 17:54:15 +010018#include <linux/cred.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070019#include <linux/posix_acl.h>
Christoph Hellwig5c8ebd52013-12-20 05:16:37 -080020#include <linux/posix_acl_xattr.h>
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -080021#include <linux/xattr.h>
Paul Gortmaker630d9c42011-11-16 23:57:37 -050022#include <linux/export.h>
Christoph Hellwig5c8ebd52013-12-20 05:16:37 -080023#include <linux/user_namespace.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070024
Andreas Gruenbacher04c57f42016-03-24 14:38:38 +010025static struct posix_acl **acl_by_type(struct inode *inode, int type)
Andrew Morton0afaa122014-01-21 15:48:42 -080026{
27 switch (type) {
28 case ACL_TYPE_ACCESS:
29 return &inode->i_acl;
30 case ACL_TYPE_DEFAULT:
31 return &inode->i_default_acl;
32 default:
33 BUG();
34 }
35}
Andrew Morton0afaa122014-01-21 15:48:42 -080036
37struct posix_acl *get_cached_acl(struct inode *inode, int type)
38{
39 struct posix_acl **p = acl_by_type(inode, type);
Andreas Gruenbacherb8a7a3a2016-03-24 14:38:37 +010040 struct posix_acl *acl;
41
42 for (;;) {
43 rcu_read_lock();
44 acl = rcu_dereference(*p);
45 if (!acl || is_uncached_acl(acl) ||
Elena Reshetova66717262017-11-29 13:19:31 +020046 refcount_inc_not_zero(&acl->a_refcount))
Andreas Gruenbacherb8a7a3a2016-03-24 14:38:37 +010047 break;
48 rcu_read_unlock();
49 cpu_relax();
Andrew Morton0afaa122014-01-21 15:48:42 -080050 }
Andreas Gruenbacherb8a7a3a2016-03-24 14:38:37 +010051 rcu_read_unlock();
Andrew Morton0afaa122014-01-21 15:48:42 -080052 return acl;
53}
54EXPORT_SYMBOL(get_cached_acl);
55
56struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type)
57{
58 return rcu_dereference(*acl_by_type(inode, type));
59}
60EXPORT_SYMBOL(get_cached_acl_rcu);
61
62void set_cached_acl(struct inode *inode, int type, struct posix_acl *acl)
63{
64 struct posix_acl **p = acl_by_type(inode, type);
65 struct posix_acl *old;
Andreas Gruenbacherb8a7a3a2016-03-24 14:38:37 +010066
67 old = xchg(p, posix_acl_dup(acl));
68 if (!is_uncached_acl(old))
Andrew Morton0afaa122014-01-21 15:48:42 -080069 posix_acl_release(old);
70}
71EXPORT_SYMBOL(set_cached_acl);
72
Andreas Gruenbacherb8a7a3a2016-03-24 14:38:37 +010073static void __forget_cached_acl(struct posix_acl **p)
74{
75 struct posix_acl *old;
76
77 old = xchg(p, ACL_NOT_CACHED);
78 if (!is_uncached_acl(old))
79 posix_acl_release(old);
80}
81
Andrew Morton0afaa122014-01-21 15:48:42 -080082void forget_cached_acl(struct inode *inode, int type)
83{
Andreas Gruenbacherb8a7a3a2016-03-24 14:38:37 +010084 __forget_cached_acl(acl_by_type(inode, type));
Andrew Morton0afaa122014-01-21 15:48:42 -080085}
86EXPORT_SYMBOL(forget_cached_acl);
87
88void forget_all_cached_acls(struct inode *inode)
89{
Andreas Gruenbacherb8a7a3a2016-03-24 14:38:37 +010090 __forget_cached_acl(&inode->i_acl);
91 __forget_cached_acl(&inode->i_default_acl);
Andrew Morton0afaa122014-01-21 15:48:42 -080092}
93EXPORT_SYMBOL(forget_all_cached_acls);
Linus Torvalds1da177e2005-04-16 15:20:36 -070094
Christoph Hellwig2982baa2013-12-20 05:16:38 -080095struct posix_acl *get_acl(struct inode *inode, int type)
96{
Andreas Gruenbacherb8a7a3a2016-03-24 14:38:37 +010097 void *sentinel;
98 struct posix_acl **p;
Christoph Hellwig2982baa2013-12-20 05:16:38 -080099 struct posix_acl *acl;
100
Andreas Gruenbacherb8a7a3a2016-03-24 14:38:37 +0100101 /*
102 * The sentinel is used to detect when another operation like
103 * set_cached_acl() or forget_cached_acl() races with get_acl().
104 * It is guaranteed that is_uncached_acl(sentinel) is true.
105 */
106
Christoph Hellwig2982baa2013-12-20 05:16:38 -0800107 acl = get_cached_acl(inode, type);
Andreas Gruenbacherb8a7a3a2016-03-24 14:38:37 +0100108 if (!is_uncached_acl(acl))
Christoph Hellwig2982baa2013-12-20 05:16:38 -0800109 return acl;
110
111 if (!IS_POSIXACL(inode))
112 return NULL;
113
Andreas Gruenbacherb8a7a3a2016-03-24 14:38:37 +0100114 sentinel = uncached_acl_sentinel(current);
115 p = acl_by_type(inode, type);
116
Christoph Hellwig2982baa2013-12-20 05:16:38 -0800117 /*
Andreas Gruenbacherb8a7a3a2016-03-24 14:38:37 +0100118 * If the ACL isn't being read yet, set our sentinel. Otherwise, the
119 * current value of the ACL will not be ACL_NOT_CACHED and so our own
120 * sentinel will not be set; another task will update the cache. We
121 * could wait for that other task to complete its job, but it's easier
122 * to just call ->get_acl to fetch the ACL ourself. (This is going to
123 * be an unlikely race.)
124 */
125 if (cmpxchg(p, ACL_NOT_CACHED, sentinel) != ACL_NOT_CACHED)
126 /* fall through */ ;
127
128 /*
129 * Normally, the ACL returned by ->get_acl will be cached.
130 * A filesystem can prevent that by calling
131 * forget_cached_acl(inode, type) in ->get_acl.
Christoph Hellwig2982baa2013-12-20 05:16:38 -0800132 *
133 * If the filesystem doesn't have a get_acl() function at all, we'll
134 * just create the negative cache entry.
135 */
136 if (!inode->i_op->get_acl) {
137 set_cached_acl(inode, type, NULL);
138 return NULL;
139 }
Andreas Gruenbacherb8a7a3a2016-03-24 14:38:37 +0100140 acl = inode->i_op->get_acl(inode, type);
141
142 if (IS_ERR(acl)) {
143 /*
144 * Remove our sentinel so that we don't block future attempts
145 * to cache the ACL.
146 */
147 cmpxchg(p, sentinel, ACL_NOT_CACHED);
148 return acl;
149 }
150
151 /*
152 * Cache the result, but only if our sentinel is still in place.
153 */
154 posix_acl_dup(acl);
155 if (unlikely(cmpxchg(p, sentinel, acl) != sentinel))
156 posix_acl_release(acl);
157 return acl;
Christoph Hellwig2982baa2013-12-20 05:16:38 -0800158}
159EXPORT_SYMBOL(get_acl);
160
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161/*
Chuck Leverf61f6da2011-01-21 03:05:38 +0000162 * Init a fresh posix_acl
163 */
164void
165posix_acl_init(struct posix_acl *acl, int count)
166{
Elena Reshetova66717262017-11-29 13:19:31 +0200167 refcount_set(&acl->a_refcount, 1);
Chuck Leverf61f6da2011-01-21 03:05:38 +0000168 acl->a_count = count;
169}
Andrew Morton0afaa122014-01-21 15:48:42 -0800170EXPORT_SYMBOL(posix_acl_init);
Chuck Leverf61f6da2011-01-21 03:05:38 +0000171
172/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173 * Allocate a new ACL with the specified number of entries.
174 */
175struct posix_acl *
Al Virodd0fc662005-10-07 07:46:04 +0100176posix_acl_alloc(int count, gfp_t flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177{
178 const size_t size = sizeof(struct posix_acl) +
179 count * sizeof(struct posix_acl_entry);
180 struct posix_acl *acl = kmalloc(size, flags);
Chuck Leverf61f6da2011-01-21 03:05:38 +0000181 if (acl)
182 posix_acl_init(acl, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183 return acl;
184}
Andrew Morton0afaa122014-01-21 15:48:42 -0800185EXPORT_SYMBOL(posix_acl_alloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186
187/*
188 * Clone an ACL.
189 */
Al Viroedde8542011-07-23 03:27:37 -0400190static struct posix_acl *
Al Virodd0fc662005-10-07 07:46:04 +0100191posix_acl_clone(const struct posix_acl *acl, gfp_t flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192{
193 struct posix_acl *clone = NULL;
194
195 if (acl) {
196 int size = sizeof(struct posix_acl) + acl->a_count *
197 sizeof(struct posix_acl_entry);
Alexey Dobriyan52978be2006-09-30 23:27:21 -0700198 clone = kmemdup(acl, size, flags);
199 if (clone)
Elena Reshetova66717262017-11-29 13:19:31 +0200200 refcount_set(&clone->a_refcount, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 }
202 return clone;
203}
204
205/*
206 * Check if an acl is valid. Returns 0 if it is, or -E... otherwise.
207 */
208int
Eric W. Biederman0d4d7172016-06-27 16:04:06 -0500209posix_acl_valid(struct user_namespace *user_ns, const struct posix_acl *acl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210{
211 const struct posix_acl_entry *pa, *pe;
212 int state = ACL_USER_OBJ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 int needs_mask = 0;
214
215 FOREACH_ACL_ENTRY(pa, acl, pe) {
216 if (pa->e_perm & ~(ACL_READ|ACL_WRITE|ACL_EXECUTE))
217 return -EINVAL;
218 switch (pa->e_tag) {
219 case ACL_USER_OBJ:
220 if (state == ACL_USER_OBJ) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221 state = ACL_USER;
222 break;
223 }
224 return -EINVAL;
225
226 case ACL_USER:
227 if (state != ACL_USER)
228 return -EINVAL;
Eric W. Biederman0d4d7172016-06-27 16:04:06 -0500229 if (!kuid_has_mapping(user_ns, pa->e_uid))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231 needs_mask = 1;
232 break;
233
234 case ACL_GROUP_OBJ:
235 if (state == ACL_USER) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236 state = ACL_GROUP;
237 break;
238 }
239 return -EINVAL;
240
241 case ACL_GROUP:
242 if (state != ACL_GROUP)
243 return -EINVAL;
Eric W. Biederman0d4d7172016-06-27 16:04:06 -0500244 if (!kgid_has_mapping(user_ns, pa->e_gid))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246 needs_mask = 1;
247 break;
248
249 case ACL_MASK:
250 if (state != ACL_GROUP)
251 return -EINVAL;
252 state = ACL_OTHER;
253 break;
254
255 case ACL_OTHER:
256 if (state == ACL_OTHER ||
257 (state == ACL_GROUP && !needs_mask)) {
258 state = 0;
259 break;
260 }
261 return -EINVAL;
262
263 default:
264 return -EINVAL;
265 }
266 }
267 if (state == 0)
268 return 0;
269 return -EINVAL;
270}
Andrew Morton0afaa122014-01-21 15:48:42 -0800271EXPORT_SYMBOL(posix_acl_valid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272
273/*
274 * Returns 0 if the acl can be exactly represented in the traditional
275 * file mode permission bits, or else 1. Returns -E... on error.
276 */
277int
Al Virod6952122011-07-23 18:56:36 -0400278posix_acl_equiv_mode(const struct posix_acl *acl, umode_t *mode_p)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279{
280 const struct posix_acl_entry *pa, *pe;
Al Virod6952122011-07-23 18:56:36 -0400281 umode_t mode = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282 int not_equiv = 0;
283
Christoph Hellwig50c6e282014-05-04 13:03:32 +0200284 /*
285 * A null ACL can always be presented as mode bits.
286 */
287 if (!acl)
288 return 0;
289
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290 FOREACH_ACL_ENTRY(pa, acl, pe) {
291 switch (pa->e_tag) {
292 case ACL_USER_OBJ:
293 mode |= (pa->e_perm & S_IRWXO) << 6;
294 break;
295 case ACL_GROUP_OBJ:
296 mode |= (pa->e_perm & S_IRWXO) << 3;
297 break;
298 case ACL_OTHER:
299 mode |= pa->e_perm & S_IRWXO;
300 break;
301 case ACL_MASK:
302 mode = (mode & ~S_IRWXG) |
303 ((pa->e_perm & S_IRWXO) << 3);
304 not_equiv = 1;
305 break;
306 case ACL_USER:
307 case ACL_GROUP:
308 not_equiv = 1;
309 break;
310 default:
311 return -EINVAL;
312 }
313 }
314 if (mode_p)
315 *mode_p = (*mode_p & ~S_IRWXUGO) | mode;
316 return not_equiv;
317}
Andrew Morton0afaa122014-01-21 15:48:42 -0800318EXPORT_SYMBOL(posix_acl_equiv_mode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319
320/*
321 * Create an ACL representing the file mode permission bits of an inode.
322 */
323struct posix_acl *
Al Viro3a5fba12011-07-23 19:01:48 -0400324posix_acl_from_mode(umode_t mode, gfp_t flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325{
326 struct posix_acl *acl = posix_acl_alloc(3, flags);
327 if (!acl)
328 return ERR_PTR(-ENOMEM);
329
330 acl->a_entries[0].e_tag = ACL_USER_OBJ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331 acl->a_entries[0].e_perm = (mode & S_IRWXU) >> 6;
332
333 acl->a_entries[1].e_tag = ACL_GROUP_OBJ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334 acl->a_entries[1].e_perm = (mode & S_IRWXG) >> 3;
335
336 acl->a_entries[2].e_tag = ACL_OTHER;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337 acl->a_entries[2].e_perm = (mode & S_IRWXO);
338 return acl;
339}
Andrew Morton0afaa122014-01-21 15:48:42 -0800340EXPORT_SYMBOL(posix_acl_from_mode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700341
342/*
343 * Return 0 if current is granted want access to the inode
344 * by the acl. Returns -E... otherwise.
345 */
346int
347posix_acl_permission(struct inode *inode, const struct posix_acl *acl, int want)
348{
349 const struct posix_acl_entry *pa, *pe, *mask_obj;
350 int found = 0;
351
Andreas Gruenbacherd124b602011-10-23 23:13:32 +0530352 want &= MAY_READ | MAY_WRITE | MAY_EXEC | MAY_NOT_BLOCK;
353
Linus Torvalds1da177e2005-04-16 15:20:36 -0700354 FOREACH_ACL_ENTRY(pa, acl, pe) {
355 switch(pa->e_tag) {
356 case ACL_USER_OBJ:
357 /* (May have been checked already) */
Eric W. Biederman2f6f0652012-02-07 18:52:57 -0800358 if (uid_eq(inode->i_uid, current_fsuid()))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359 goto check_perm;
360 break;
361 case ACL_USER:
Eric W. Biederman2f6f0652012-02-07 18:52:57 -0800362 if (uid_eq(pa->e_uid, current_fsuid()))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363 goto mask;
364 break;
365 case ACL_GROUP_OBJ:
366 if (in_group_p(inode->i_gid)) {
367 found = 1;
368 if ((pa->e_perm & want) == want)
369 goto mask;
370 }
371 break;
372 case ACL_GROUP:
Eric W. Biederman2f6f0652012-02-07 18:52:57 -0800373 if (in_group_p(pa->e_gid)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374 found = 1;
375 if ((pa->e_perm & want) == want)
376 goto mask;
377 }
378 break;
379 case ACL_MASK:
380 break;
381 case ACL_OTHER:
382 if (found)
383 return -EACCES;
384 else
385 goto check_perm;
386 default:
387 return -EIO;
388 }
389 }
390 return -EIO;
391
392mask:
393 for (mask_obj = pa+1; mask_obj != pe; mask_obj++) {
394 if (mask_obj->e_tag == ACL_MASK) {
395 if ((pa->e_perm & mask_obj->e_perm & want) == want)
396 return 0;
397 return -EACCES;
398 }
399 }
400
401check_perm:
402 if ((pa->e_perm & want) == want)
403 return 0;
404 return -EACCES;
405}
406
407/*
408 * Modify acl when creating a new inode. The caller must ensure the acl is
409 * only referenced once.
410 *
411 * mode_p initially must contain the mode parameter to the open() / creat()
412 * system calls. All permissions that are not granted by the acl are removed.
413 * The permissions in the acl are changed to reflect the mode_p parameter.
414 */
Al Virod3fb6122011-07-23 18:37:50 -0400415static int posix_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416{
417 struct posix_acl_entry *pa, *pe;
418 struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
Al Virod3fb6122011-07-23 18:37:50 -0400419 umode_t mode = *mode_p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420 int not_equiv = 0;
421
422 /* assert(atomic_read(acl->a_refcount) == 1); */
423
424 FOREACH_ACL_ENTRY(pa, acl, pe) {
425 switch(pa->e_tag) {
426 case ACL_USER_OBJ:
427 pa->e_perm &= (mode >> 6) | ~S_IRWXO;
428 mode &= (pa->e_perm << 6) | ~S_IRWXU;
429 break;
430
431 case ACL_USER:
432 case ACL_GROUP:
433 not_equiv = 1;
434 break;
435
436 case ACL_GROUP_OBJ:
437 group_obj = pa;
438 break;
439
440 case ACL_OTHER:
441 pa->e_perm &= mode | ~S_IRWXO;
442 mode &= pa->e_perm | ~S_IRWXO;
443 break;
444
445 case ACL_MASK:
446 mask_obj = pa;
447 not_equiv = 1;
448 break;
449
450 default:
451 return -EIO;
452 }
453 }
454
455 if (mask_obj) {
456 mask_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
457 mode &= (mask_obj->e_perm << 3) | ~S_IRWXG;
458 } else {
459 if (!group_obj)
460 return -EIO;
461 group_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
462 mode &= (group_obj->e_perm << 3) | ~S_IRWXG;
463 }
464
465 *mode_p = (*mode_p & ~S_IRWXUGO) | mode;
466 return not_equiv;
467}
468
469/*
470 * Modify the ACL for the chmod syscall.
471 */
Christoph Hellwig5bf32582013-12-20 05:16:41 -0800472static int __posix_acl_chmod_masq(struct posix_acl *acl, umode_t mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700473{
474 struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
475 struct posix_acl_entry *pa, *pe;
476
477 /* assert(atomic_read(acl->a_refcount) == 1); */
478
479 FOREACH_ACL_ENTRY(pa, acl, pe) {
480 switch(pa->e_tag) {
481 case ACL_USER_OBJ:
482 pa->e_perm = (mode & S_IRWXU) >> 6;
483 break;
484
485 case ACL_USER:
486 case ACL_GROUP:
487 break;
488
489 case ACL_GROUP_OBJ:
490 group_obj = pa;
491 break;
492
493 case ACL_MASK:
494 mask_obj = pa;
495 break;
496
497 case ACL_OTHER:
498 pa->e_perm = (mode & S_IRWXO);
499 break;
500
501 default:
502 return -EIO;
503 }
504 }
505
506 if (mask_obj) {
507 mask_obj->e_perm = (mode & S_IRWXG) >> 3;
508 } else {
509 if (!group_obj)
510 return -EIO;
511 group_obj->e_perm = (mode & S_IRWXG) >> 3;
512 }
513
514 return 0;
515}
Al Virobc26ab52011-07-23 00:18:02 -0400516
517int
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800518__posix_acl_create(struct posix_acl **acl, gfp_t gfp, umode_t *mode_p)
Al Viro826cae22011-07-23 03:10:32 -0400519{
520 struct posix_acl *clone = posix_acl_clone(*acl, gfp);
521 int err = -ENOMEM;
522 if (clone) {
523 err = posix_acl_create_masq(clone, mode_p);
524 if (err < 0) {
525 posix_acl_release(clone);
526 clone = NULL;
527 }
528 }
529 posix_acl_release(*acl);
530 *acl = clone;
531 return err;
532}
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800533EXPORT_SYMBOL(__posix_acl_create);
Al Viro826cae22011-07-23 03:10:32 -0400534
535int
Christoph Hellwig5bf32582013-12-20 05:16:41 -0800536__posix_acl_chmod(struct posix_acl **acl, gfp_t gfp, umode_t mode)
Al Virobc26ab52011-07-23 00:18:02 -0400537{
538 struct posix_acl *clone = posix_acl_clone(*acl, gfp);
539 int err = -ENOMEM;
540 if (clone) {
Christoph Hellwig5bf32582013-12-20 05:16:41 -0800541 err = __posix_acl_chmod_masq(clone, mode);
Al Virobc26ab52011-07-23 00:18:02 -0400542 if (err) {
543 posix_acl_release(clone);
544 clone = NULL;
545 }
546 }
547 posix_acl_release(*acl);
548 *acl = clone;
549 return err;
550}
Christoph Hellwig5bf32582013-12-20 05:16:41 -0800551EXPORT_SYMBOL(__posix_acl_chmod);
552
553int
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800554posix_acl_chmod(struct inode *inode, umode_t mode)
Christoph Hellwig5bf32582013-12-20 05:16:41 -0800555{
556 struct posix_acl *acl;
557 int ret = 0;
558
559 if (!IS_POSIXACL(inode))
560 return 0;
561 if (!inode->i_op->set_acl)
562 return -EOPNOTSUPP;
563
564 acl = get_acl(inode, ACL_TYPE_ACCESS);
Trond Myklebust789b6632014-01-31 14:25:19 -0500565 if (IS_ERR_OR_NULL(acl)) {
566 if (acl == ERR_PTR(-EOPNOTSUPP))
567 return 0;
Christoph Hellwig5bf32582013-12-20 05:16:41 -0800568 return PTR_ERR(acl);
Trond Myklebust789b6632014-01-31 14:25:19 -0500569 }
Christoph Hellwig5bf32582013-12-20 05:16:41 -0800570
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800571 ret = __posix_acl_chmod(&acl, GFP_KERNEL, mode);
Christoph Hellwig5bf32582013-12-20 05:16:41 -0800572 if (ret)
573 return ret;
574 ret = inode->i_op->set_acl(inode, acl, ACL_TYPE_ACCESS);
575 posix_acl_release(acl);
576 return ret;
577}
Al Virobc26ab52011-07-23 00:18:02 -0400578EXPORT_SYMBOL(posix_acl_chmod);
Christoph Hellwig5c8ebd52013-12-20 05:16:37 -0800579
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800580int
581posix_acl_create(struct inode *dir, umode_t *mode,
582 struct posix_acl **default_acl, struct posix_acl **acl)
583{
584 struct posix_acl *p;
Dan Carpenterc0c3a712015-06-19 09:00:55 +1000585 struct posix_acl *clone;
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800586 int ret;
587
Dan Carpenterc0c3a712015-06-19 09:00:55 +1000588 *acl = NULL;
589 *default_acl = NULL;
590
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800591 if (S_ISLNK(*mode) || !IS_POSIXACL(dir))
Dan Carpenterc0c3a712015-06-19 09:00:55 +1000592 return 0;
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800593
594 p = get_acl(dir, ACL_TYPE_DEFAULT);
Dan Carpenterc0c3a712015-06-19 09:00:55 +1000595 if (!p || p == ERR_PTR(-EOPNOTSUPP)) {
596 *mode &= ~current_umask();
597 return 0;
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800598 }
Dan Carpenterc0c3a712015-06-19 09:00:55 +1000599 if (IS_ERR(p))
600 return PTR_ERR(p);
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800601
Miklos Szeredibeaf2262016-09-16 12:44:21 +0200602 ret = -ENOMEM;
Dan Carpenterc0c3a712015-06-19 09:00:55 +1000603 clone = posix_acl_clone(p, GFP_NOFS);
604 if (!clone)
Miklos Szeredibeaf2262016-09-16 12:44:21 +0200605 goto err_release;
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800606
Dan Carpenterc0c3a712015-06-19 09:00:55 +1000607 ret = posix_acl_create_masq(clone, mode);
Omar Sandovalfed0b582015-02-08 21:45:25 -0800608 if (ret < 0)
Miklos Szeredibeaf2262016-09-16 12:44:21 +0200609 goto err_release_clone;
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800610
Dan Carpenterc0c3a712015-06-19 09:00:55 +1000611 if (ret == 0)
612 posix_acl_release(clone);
613 else
614 *acl = clone;
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800615
Dan Carpenterc0c3a712015-06-19 09:00:55 +1000616 if (!S_ISDIR(*mode))
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800617 posix_acl_release(p);
Dan Carpenterc0c3a712015-06-19 09:00:55 +1000618 else
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800619 *default_acl = p;
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800620
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800621 return 0;
Omar Sandovalfed0b582015-02-08 21:45:25 -0800622
Miklos Szeredibeaf2262016-09-16 12:44:21 +0200623err_release_clone:
Dan Carpenterc0c3a712015-06-19 09:00:55 +1000624 posix_acl_release(clone);
Miklos Szeredibeaf2262016-09-16 12:44:21 +0200625err_release:
Omar Sandovalfed0b582015-02-08 21:45:25 -0800626 posix_acl_release(p);
Miklos Szeredibeaf2262016-09-16 12:44:21 +0200627 return ret;
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800628}
629EXPORT_SYMBOL_GPL(posix_acl_create);
630
Jan Kara07393102016-09-19 17:39:09 +0200631/**
632 * posix_acl_update_mode - update mode in set_acl
633 *
634 * Update the file mode when setting an ACL: compute the new file permission
635 * bits based on the ACL. In addition, if the ACL is equivalent to the new
636 * file mode, set *acl to NULL to indicate that no ACL should be set.
637 *
638 * As with chmod, clear the setgit bit if the caller is not in the owning group
639 * or capable of CAP_FSETID (see inode_change_ok).
640 *
641 * Called from set_acl inode operations.
642 */
643int posix_acl_update_mode(struct inode *inode, umode_t *mode_p,
644 struct posix_acl **acl)
645{
646 umode_t mode = inode->i_mode;
647 int error;
648
649 error = posix_acl_equiv_mode(*acl, &mode);
650 if (error < 0)
651 return error;
652 if (error == 0)
653 *acl = NULL;
654 if (!in_group_p(inode->i_gid) &&
655 !capable_wrt_inode_uidgid(inode, CAP_FSETID))
656 mode &= ~S_ISGID;
657 *mode_p = mode;
658 return 0;
659}
660EXPORT_SYMBOL(posix_acl_update_mode);
661
Christoph Hellwig5c8ebd52013-12-20 05:16:37 -0800662/*
663 * Fix up the uids and gids in posix acl extended attributes in place.
664 */
665static void posix_acl_fix_xattr_userns(
666 struct user_namespace *to, struct user_namespace *from,
667 void *value, size_t size)
668{
Andreas Gruenbacher2211d5b2016-09-27 13:03:22 +0200669 struct posix_acl_xattr_header *header = value;
670 struct posix_acl_xattr_entry *entry = (void *)(header + 1), *end;
Christoph Hellwig5c8ebd52013-12-20 05:16:37 -0800671 int count;
672 kuid_t uid;
673 kgid_t gid;
674
675 if (!value)
676 return;
Andreas Gruenbacher2211d5b2016-09-27 13:03:22 +0200677 if (size < sizeof(struct posix_acl_xattr_header))
Christoph Hellwig5c8ebd52013-12-20 05:16:37 -0800678 return;
679 if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
680 return;
681
682 count = posix_acl_xattr_count(size);
683 if (count < 0)
684 return;
685 if (count == 0)
686 return;
687
688 for (end = entry + count; entry != end; entry++) {
689 switch(le16_to_cpu(entry->e_tag)) {
690 case ACL_USER:
691 uid = make_kuid(from, le32_to_cpu(entry->e_id));
692 entry->e_id = cpu_to_le32(from_kuid(to, uid));
693 break;
694 case ACL_GROUP:
695 gid = make_kgid(from, le32_to_cpu(entry->e_id));
696 entry->e_id = cpu_to_le32(from_kgid(to, gid));
697 break;
698 default:
699 break;
700 }
701 }
702}
703
704void posix_acl_fix_xattr_from_user(void *value, size_t size)
705{
706 struct user_namespace *user_ns = current_user_ns();
707 if (user_ns == &init_user_ns)
708 return;
709 posix_acl_fix_xattr_userns(&init_user_ns, user_ns, value, size);
710}
711
712void posix_acl_fix_xattr_to_user(void *value, size_t size)
713{
714 struct user_namespace *user_ns = current_user_ns();
715 if (user_ns == &init_user_ns)
716 return;
717 posix_acl_fix_xattr_userns(user_ns, &init_user_ns, value, size);
718}
719
720/*
721 * Convert from extended attribute to in-memory representation.
722 */
723struct posix_acl *
724posix_acl_from_xattr(struct user_namespace *user_ns,
725 const void *value, size_t size)
726{
Andreas Gruenbacher2211d5b2016-09-27 13:03:22 +0200727 const struct posix_acl_xattr_header *header = value;
728 const struct posix_acl_xattr_entry *entry = (const void *)(header + 1), *end;
Christoph Hellwig5c8ebd52013-12-20 05:16:37 -0800729 int count;
730 struct posix_acl *acl;
731 struct posix_acl_entry *acl_e;
732
733 if (!value)
734 return NULL;
Andreas Gruenbacher2211d5b2016-09-27 13:03:22 +0200735 if (size < sizeof(struct posix_acl_xattr_header))
Christoph Hellwig5c8ebd52013-12-20 05:16:37 -0800736 return ERR_PTR(-EINVAL);
737 if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
738 return ERR_PTR(-EOPNOTSUPP);
739
740 count = posix_acl_xattr_count(size);
741 if (count < 0)
742 return ERR_PTR(-EINVAL);
743 if (count == 0)
744 return NULL;
745
746 acl = posix_acl_alloc(count, GFP_NOFS);
747 if (!acl)
748 return ERR_PTR(-ENOMEM);
749 acl_e = acl->a_entries;
750
751 for (end = entry + count; entry != end; acl_e++, entry++) {
752 acl_e->e_tag = le16_to_cpu(entry->e_tag);
753 acl_e->e_perm = le16_to_cpu(entry->e_perm);
754
755 switch(acl_e->e_tag) {
756 case ACL_USER_OBJ:
757 case ACL_GROUP_OBJ:
758 case ACL_MASK:
759 case ACL_OTHER:
760 break;
761
762 case ACL_USER:
763 acl_e->e_uid =
764 make_kuid(user_ns,
765 le32_to_cpu(entry->e_id));
766 if (!uid_valid(acl_e->e_uid))
767 goto fail;
768 break;
769 case ACL_GROUP:
770 acl_e->e_gid =
771 make_kgid(user_ns,
772 le32_to_cpu(entry->e_id));
773 if (!gid_valid(acl_e->e_gid))
774 goto fail;
775 break;
776
777 default:
778 goto fail;
779 }
780 }
781 return acl;
782
783fail:
784 posix_acl_release(acl);
785 return ERR_PTR(-EINVAL);
786}
787EXPORT_SYMBOL (posix_acl_from_xattr);
788
789/*
790 * Convert from in-memory to extended attribute representation.
791 */
792int
793posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl,
794 void *buffer, size_t size)
795{
Andreas Gruenbacher2211d5b2016-09-27 13:03:22 +0200796 struct posix_acl_xattr_header *ext_acl = buffer;
797 struct posix_acl_xattr_entry *ext_entry;
Christoph Hellwig5c8ebd52013-12-20 05:16:37 -0800798 int real_size, n;
799
800 real_size = posix_acl_xattr_size(acl->a_count);
801 if (!buffer)
802 return real_size;
803 if (real_size > size)
804 return -ERANGE;
Dan Carpenter47ba9732014-02-14 12:05:49 +0300805
Andreas Gruenbacher2211d5b2016-09-27 13:03:22 +0200806 ext_entry = (void *)(ext_acl + 1);
Christoph Hellwig5c8ebd52013-12-20 05:16:37 -0800807 ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);
808
809 for (n=0; n < acl->a_count; n++, ext_entry++) {
810 const struct posix_acl_entry *acl_e = &acl->a_entries[n];
811 ext_entry->e_tag = cpu_to_le16(acl_e->e_tag);
812 ext_entry->e_perm = cpu_to_le16(acl_e->e_perm);
813 switch(acl_e->e_tag) {
814 case ACL_USER:
815 ext_entry->e_id =
816 cpu_to_le32(from_kuid(user_ns, acl_e->e_uid));
817 break;
818 case ACL_GROUP:
819 ext_entry->e_id =
820 cpu_to_le32(from_kgid(user_ns, acl_e->e_gid));
821 break;
822 default:
823 ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID);
824 break;
825 }
826 }
827 return real_size;
828}
829EXPORT_SYMBOL (posix_acl_to_xattr);
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800830
831static int
Andreas Gruenbacherd9a82a02015-10-04 19:18:51 +0200832posix_acl_xattr_get(const struct xattr_handler *handler,
Al Virob2968212016-04-10 20:48:24 -0400833 struct dentry *unused, struct inode *inode,
834 const char *name, void *value, size_t size)
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800835{
836 struct posix_acl *acl;
837 int error;
838
Al Virob2968212016-04-10 20:48:24 -0400839 if (!IS_POSIXACL(inode))
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800840 return -EOPNOTSUPP;
Al Virob2968212016-04-10 20:48:24 -0400841 if (S_ISLNK(inode->i_mode))
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800842 return -EOPNOTSUPP;
843
Al Virob2968212016-04-10 20:48:24 -0400844 acl = get_acl(inode, handler->flags);
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800845 if (IS_ERR(acl))
846 return PTR_ERR(acl);
847 if (acl == NULL)
848 return -ENODATA;
849
850 error = posix_acl_to_xattr(&init_user_ns, acl, value, size);
851 posix_acl_release(acl);
852
853 return error;
854}
855
Andreas Gruenbacher485e71e2016-06-22 23:57:25 +0200856int
857set_posix_acl(struct inode *inode, int type, struct posix_acl *acl)
858{
859 if (!IS_POSIXACL(inode))
860 return -EOPNOTSUPP;
861 if (!inode->i_op->set_acl)
862 return -EOPNOTSUPP;
863
864 if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
865 return acl ? -EACCES : 0;
866 if (!inode_owner_or_capable(inode))
867 return -EPERM;
868
869 if (acl) {
Linus Torvaldsa867d732016-07-29 15:54:19 -0700870 int ret = posix_acl_valid(inode->i_sb->s_user_ns, acl);
Andreas Gruenbacher485e71e2016-06-22 23:57:25 +0200871 if (ret)
872 return ret;
873 }
874 return inode->i_op->set_acl(inode, acl, type);
875}
876EXPORT_SYMBOL(set_posix_acl);
877
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800878static int
Andreas Gruenbacherd9a82a02015-10-04 19:18:51 +0200879posix_acl_xattr_set(const struct xattr_handler *handler,
Al Viro59301222016-05-27 10:19:30 -0400880 struct dentry *unused, struct inode *inode,
881 const char *name, const void *value,
882 size_t size, int flags)
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800883{
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800884 struct posix_acl *acl = NULL;
885 int ret;
886
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800887 if (value) {
888 acl = posix_acl_from_xattr(&init_user_ns, value, size);
889 if (IS_ERR(acl))
890 return PTR_ERR(acl);
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800891 }
Andreas Gruenbacher485e71e2016-06-22 23:57:25 +0200892 ret = set_posix_acl(inode, handler->flags, acl);
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800893 posix_acl_release(acl);
894 return ret;
895}
896
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100897static bool
898posix_acl_xattr_list(struct dentry *dentry)
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800899{
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100900 return IS_POSIXACL(d_backing_inode(dentry));
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800901}
902
903const struct xattr_handler posix_acl_access_xattr_handler = {
Andreas Gruenbacher98e9cb52015-12-02 14:44:36 +0100904 .name = XATTR_NAME_POSIX_ACL_ACCESS,
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800905 .flags = ACL_TYPE_ACCESS,
906 .list = posix_acl_xattr_list,
907 .get = posix_acl_xattr_get,
908 .set = posix_acl_xattr_set,
909};
910EXPORT_SYMBOL_GPL(posix_acl_access_xattr_handler);
911
912const struct xattr_handler posix_acl_default_xattr_handler = {
Andreas Gruenbacher98e9cb52015-12-02 14:44:36 +0100913 .name = XATTR_NAME_POSIX_ACL_DEFAULT,
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800914 .flags = ACL_TYPE_DEFAULT,
915 .list = posix_acl_xattr_list,
916 .get = posix_acl_xattr_get,
917 .set = posix_acl_xattr_set,
918};
919EXPORT_SYMBOL_GPL(posix_acl_default_xattr_handler);
Christoph Hellwigfeda8212013-12-20 05:16:54 -0800920
921int simple_set_acl(struct inode *inode, struct posix_acl *acl, int type)
922{
923 int error;
924
925 if (type == ACL_TYPE_ACCESS) {
Gu Zheng497de072017-01-09 09:34:48 +0800926 error = posix_acl_update_mode(inode,
927 &inode->i_mode, &acl);
928 if (error)
929 return error;
Christoph Hellwigfeda8212013-12-20 05:16:54 -0800930 }
931
Deepa Dinamani078cd822016-09-14 07:48:04 -0700932 inode->i_ctime = current_time(inode);
Christoph Hellwigfeda8212013-12-20 05:16:54 -0800933 set_cached_acl(inode, type, acl);
934 return 0;
935}
936
937int simple_acl_create(struct inode *dir, struct inode *inode)
938{
939 struct posix_acl *default_acl, *acl;
940 int error;
941
942 error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
943 if (error)
944 return error;
945
946 set_cached_acl(inode, ACL_TYPE_DEFAULT, default_acl);
947 set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
948
949 if (default_acl)
950 posix_acl_release(default_acl);
951 if (acl)
952 posix_acl_release(acl);
953 return 0;
954}