blob: 595522022aca04beeeabd3d2ed4e73992f268296 [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
Andreas Gruenbacher04c57f42016-03-24 14:38:38 +010024static struct posix_acl **acl_by_type(struct inode *inode, int type)
Andrew Morton0afaa122014-01-21 15:48:42 -080025{
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}
Andrew Morton0afaa122014-01-21 15:48:42 -080035
36struct posix_acl *get_cached_acl(struct inode *inode, int type)
37{
38 struct posix_acl **p = acl_by_type(inode, type);
Andreas Gruenbacherb8a7a3a2016-03-24 14:38:37 +010039 struct posix_acl *acl;
40
41 for (;;) {
42 rcu_read_lock();
43 acl = rcu_dereference(*p);
44 if (!acl || is_uncached_acl(acl) ||
45 atomic_inc_not_zero(&acl->a_refcount))
46 break;
47 rcu_read_unlock();
48 cpu_relax();
Andrew Morton0afaa122014-01-21 15:48:42 -080049 }
Andreas Gruenbacherb8a7a3a2016-03-24 14:38:37 +010050 rcu_read_unlock();
Andrew Morton0afaa122014-01-21 15:48:42 -080051 return acl;
52}
53EXPORT_SYMBOL(get_cached_acl);
54
55struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type)
56{
57 return rcu_dereference(*acl_by_type(inode, type));
58}
59EXPORT_SYMBOL(get_cached_acl_rcu);
60
61void set_cached_acl(struct inode *inode, int type, struct posix_acl *acl)
62{
63 struct posix_acl **p = acl_by_type(inode, type);
64 struct posix_acl *old;
Andreas Gruenbacherb8a7a3a2016-03-24 14:38:37 +010065
66 old = xchg(p, posix_acl_dup(acl));
67 if (!is_uncached_acl(old))
Andrew Morton0afaa122014-01-21 15:48:42 -080068 posix_acl_release(old);
69}
70EXPORT_SYMBOL(set_cached_acl);
71
Andreas Gruenbacherb8a7a3a2016-03-24 14:38:37 +010072static void __forget_cached_acl(struct posix_acl **p)
73{
74 struct posix_acl *old;
75
76 old = xchg(p, ACL_NOT_CACHED);
77 if (!is_uncached_acl(old))
78 posix_acl_release(old);
79}
80
Andrew Morton0afaa122014-01-21 15:48:42 -080081void forget_cached_acl(struct inode *inode, int type)
82{
Andreas Gruenbacherb8a7a3a2016-03-24 14:38:37 +010083 __forget_cached_acl(acl_by_type(inode, type));
Andrew Morton0afaa122014-01-21 15:48:42 -080084}
85EXPORT_SYMBOL(forget_cached_acl);
86
87void forget_all_cached_acls(struct inode *inode)
88{
Andreas Gruenbacherb8a7a3a2016-03-24 14:38:37 +010089 __forget_cached_acl(&inode->i_acl);
90 __forget_cached_acl(&inode->i_default_acl);
Andrew Morton0afaa122014-01-21 15:48:42 -080091}
92EXPORT_SYMBOL(forget_all_cached_acls);
Linus Torvalds1da177e2005-04-16 15:20:36 -070093
Christoph Hellwig2982baa2013-12-20 05:16:38 -080094struct posix_acl *get_acl(struct inode *inode, int type)
95{
Andreas Gruenbacherb8a7a3a2016-03-24 14:38:37 +010096 void *sentinel;
97 struct posix_acl **p;
Christoph Hellwig2982baa2013-12-20 05:16:38 -080098 struct posix_acl *acl;
99
Andreas Gruenbacherb8a7a3a2016-03-24 14:38:37 +0100100 /*
101 * The sentinel is used to detect when another operation like
102 * set_cached_acl() or forget_cached_acl() races with get_acl().
103 * It is guaranteed that is_uncached_acl(sentinel) is true.
104 */
105
Christoph Hellwig2982baa2013-12-20 05:16:38 -0800106 acl = get_cached_acl(inode, type);
Andreas Gruenbacherb8a7a3a2016-03-24 14:38:37 +0100107 if (!is_uncached_acl(acl))
Christoph Hellwig2982baa2013-12-20 05:16:38 -0800108 return acl;
109
110 if (!IS_POSIXACL(inode))
111 return NULL;
112
Andreas Gruenbacherb8a7a3a2016-03-24 14:38:37 +0100113 sentinel = uncached_acl_sentinel(current);
114 p = acl_by_type(inode, type);
115
Christoph Hellwig2982baa2013-12-20 05:16:38 -0800116 /*
Andreas Gruenbacherb8a7a3a2016-03-24 14:38:37 +0100117 * If the ACL isn't being read yet, set our sentinel. Otherwise, the
118 * current value of the ACL will not be ACL_NOT_CACHED and so our own
119 * sentinel will not be set; another task will update the cache. We
120 * could wait for that other task to complete its job, but it's easier
121 * to just call ->get_acl to fetch the ACL ourself. (This is going to
122 * be an unlikely race.)
123 */
124 if (cmpxchg(p, ACL_NOT_CACHED, sentinel) != ACL_NOT_CACHED)
125 /* fall through */ ;
126
127 /*
128 * Normally, the ACL returned by ->get_acl will be cached.
129 * A filesystem can prevent that by calling
130 * forget_cached_acl(inode, type) in ->get_acl.
Christoph Hellwig2982baa2013-12-20 05:16:38 -0800131 *
132 * If the filesystem doesn't have a get_acl() function at all, we'll
133 * just create the negative cache entry.
134 */
135 if (!inode->i_op->get_acl) {
136 set_cached_acl(inode, type, NULL);
137 return NULL;
138 }
Andreas Gruenbacherb8a7a3a2016-03-24 14:38:37 +0100139 acl = inode->i_op->get_acl(inode, type);
140
141 if (IS_ERR(acl)) {
142 /*
143 * Remove our sentinel so that we don't block future attempts
144 * to cache the ACL.
145 */
146 cmpxchg(p, sentinel, ACL_NOT_CACHED);
147 return acl;
148 }
149
150 /*
151 * Cache the result, but only if our sentinel is still in place.
152 */
153 posix_acl_dup(acl);
154 if (unlikely(cmpxchg(p, sentinel, acl) != sentinel))
155 posix_acl_release(acl);
156 return acl;
Christoph Hellwig2982baa2013-12-20 05:16:38 -0800157}
158EXPORT_SYMBOL(get_acl);
159
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160/*
Chuck Leverf61f6da2011-01-21 03:05:38 +0000161 * Init a fresh posix_acl
162 */
163void
164posix_acl_init(struct posix_acl *acl, int count)
165{
166 atomic_set(&acl->a_refcount, 1);
167 acl->a_count = count;
168}
Andrew Morton0afaa122014-01-21 15:48:42 -0800169EXPORT_SYMBOL(posix_acl_init);
Chuck Leverf61f6da2011-01-21 03:05:38 +0000170
171/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172 * Allocate a new ACL with the specified number of entries.
173 */
174struct posix_acl *
Al Virodd0fc662005-10-07 07:46:04 +0100175posix_acl_alloc(int count, gfp_t flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176{
177 const size_t size = sizeof(struct posix_acl) +
178 count * sizeof(struct posix_acl_entry);
179 struct posix_acl *acl = kmalloc(size, flags);
Chuck Leverf61f6da2011-01-21 03:05:38 +0000180 if (acl)
181 posix_acl_init(acl, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182 return acl;
183}
Andrew Morton0afaa122014-01-21 15:48:42 -0800184EXPORT_SYMBOL(posix_acl_alloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185
186/*
187 * Clone an ACL.
188 */
Al Viroedde8542011-07-23 03:27:37 -0400189static struct posix_acl *
Al Virodd0fc662005-10-07 07:46:04 +0100190posix_acl_clone(const struct posix_acl *acl, gfp_t flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191{
192 struct posix_acl *clone = NULL;
193
194 if (acl) {
195 int size = sizeof(struct posix_acl) + acl->a_count *
196 sizeof(struct posix_acl_entry);
Alexey Dobriyan52978be2006-09-30 23:27:21 -0700197 clone = kmemdup(acl, size, flags);
198 if (clone)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199 atomic_set(&clone->a_refcount, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 }
201 return clone;
202}
203
204/*
205 * Check if an acl is valid. Returns 0 if it is, or -E... otherwise.
206 */
207int
Eric W. Biederman0d4d7172016-06-27 16:04:06 -0500208posix_acl_valid(struct user_namespace *user_ns, const struct posix_acl *acl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209{
210 const struct posix_acl_entry *pa, *pe;
211 int state = ACL_USER_OBJ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212 int needs_mask = 0;
213
214 FOREACH_ACL_ENTRY(pa, acl, pe) {
215 if (pa->e_perm & ~(ACL_READ|ACL_WRITE|ACL_EXECUTE))
216 return -EINVAL;
217 switch (pa->e_tag) {
218 case ACL_USER_OBJ:
219 if (state == ACL_USER_OBJ) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 state = ACL_USER;
221 break;
222 }
223 return -EINVAL;
224
225 case ACL_USER:
226 if (state != ACL_USER)
227 return -EINVAL;
Eric W. Biederman0d4d7172016-06-27 16:04:06 -0500228 if (!kuid_has_mapping(user_ns, pa->e_uid))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230 needs_mask = 1;
231 break;
232
233 case ACL_GROUP_OBJ:
234 if (state == ACL_USER) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235 state = ACL_GROUP;
236 break;
237 }
238 return -EINVAL;
239
240 case ACL_GROUP:
241 if (state != ACL_GROUP)
242 return -EINVAL;
Eric W. Biederman0d4d7172016-06-27 16:04:06 -0500243 if (!kgid_has_mapping(user_ns, pa->e_gid))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245 needs_mask = 1;
246 break;
247
248 case ACL_MASK:
249 if (state != ACL_GROUP)
250 return -EINVAL;
251 state = ACL_OTHER;
252 break;
253
254 case ACL_OTHER:
255 if (state == ACL_OTHER ||
256 (state == ACL_GROUP && !needs_mask)) {
257 state = 0;
258 break;
259 }
260 return -EINVAL;
261
262 default:
263 return -EINVAL;
264 }
265 }
266 if (state == 0)
267 return 0;
268 return -EINVAL;
269}
Andrew Morton0afaa122014-01-21 15:48:42 -0800270EXPORT_SYMBOL(posix_acl_valid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271
272/*
273 * Returns 0 if the acl can be exactly represented in the traditional
274 * file mode permission bits, or else 1. Returns -E... on error.
275 */
276int
Al Virod6952122011-07-23 18:56:36 -0400277posix_acl_equiv_mode(const struct posix_acl *acl, umode_t *mode_p)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278{
279 const struct posix_acl_entry *pa, *pe;
Al Virod6952122011-07-23 18:56:36 -0400280 umode_t mode = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281 int not_equiv = 0;
282
Christoph Hellwig50c6e282014-05-04 13:03:32 +0200283 /*
284 * A null ACL can always be presented as mode bits.
285 */
286 if (!acl)
287 return 0;
288
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289 FOREACH_ACL_ENTRY(pa, acl, pe) {
290 switch (pa->e_tag) {
291 case ACL_USER_OBJ:
292 mode |= (pa->e_perm & S_IRWXO) << 6;
293 break;
294 case ACL_GROUP_OBJ:
295 mode |= (pa->e_perm & S_IRWXO) << 3;
296 break;
297 case ACL_OTHER:
298 mode |= pa->e_perm & S_IRWXO;
299 break;
300 case ACL_MASK:
301 mode = (mode & ~S_IRWXG) |
302 ((pa->e_perm & S_IRWXO) << 3);
303 not_equiv = 1;
304 break;
305 case ACL_USER:
306 case ACL_GROUP:
307 not_equiv = 1;
308 break;
309 default:
310 return -EINVAL;
311 }
312 }
313 if (mode_p)
314 *mode_p = (*mode_p & ~S_IRWXUGO) | mode;
315 return not_equiv;
316}
Andrew Morton0afaa122014-01-21 15:48:42 -0800317EXPORT_SYMBOL(posix_acl_equiv_mode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318
319/*
320 * Create an ACL representing the file mode permission bits of an inode.
321 */
322struct posix_acl *
Al Viro3a5fba12011-07-23 19:01:48 -0400323posix_acl_from_mode(umode_t mode, gfp_t flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324{
325 struct posix_acl *acl = posix_acl_alloc(3, flags);
326 if (!acl)
327 return ERR_PTR(-ENOMEM);
328
329 acl->a_entries[0].e_tag = ACL_USER_OBJ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330 acl->a_entries[0].e_perm = (mode & S_IRWXU) >> 6;
331
332 acl->a_entries[1].e_tag = ACL_GROUP_OBJ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333 acl->a_entries[1].e_perm = (mode & S_IRWXG) >> 3;
334
335 acl->a_entries[2].e_tag = ACL_OTHER;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336 acl->a_entries[2].e_perm = (mode & S_IRWXO);
337 return acl;
338}
Andrew Morton0afaa122014-01-21 15:48:42 -0800339EXPORT_SYMBOL(posix_acl_from_mode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340
341/*
342 * Return 0 if current is granted want access to the inode
343 * by the acl. Returns -E... otherwise.
344 */
345int
346posix_acl_permission(struct inode *inode, const struct posix_acl *acl, int want)
347{
348 const struct posix_acl_entry *pa, *pe, *mask_obj;
349 int found = 0;
350
Andreas Gruenbacherd124b602011-10-23 23:13:32 +0530351 want &= MAY_READ | MAY_WRITE | MAY_EXEC | MAY_NOT_BLOCK;
352
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353 FOREACH_ACL_ENTRY(pa, acl, pe) {
354 switch(pa->e_tag) {
355 case ACL_USER_OBJ:
356 /* (May have been checked already) */
Eric W. Biederman2f6f0652012-02-07 18:52:57 -0800357 if (uid_eq(inode->i_uid, current_fsuid()))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700358 goto check_perm;
359 break;
360 case ACL_USER:
Eric W. Biederman2f6f0652012-02-07 18:52:57 -0800361 if (uid_eq(pa->e_uid, current_fsuid()))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362 goto mask;
363 break;
364 case ACL_GROUP_OBJ:
365 if (in_group_p(inode->i_gid)) {
366 found = 1;
367 if ((pa->e_perm & want) == want)
368 goto mask;
369 }
370 break;
371 case ACL_GROUP:
Eric W. Biederman2f6f0652012-02-07 18:52:57 -0800372 if (in_group_p(pa->e_gid)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373 found = 1;
374 if ((pa->e_perm & want) == want)
375 goto mask;
376 }
377 break;
378 case ACL_MASK:
379 break;
380 case ACL_OTHER:
381 if (found)
382 return -EACCES;
383 else
384 goto check_perm;
385 default:
386 return -EIO;
387 }
388 }
389 return -EIO;
390
391mask:
392 for (mask_obj = pa+1; mask_obj != pe; mask_obj++) {
393 if (mask_obj->e_tag == ACL_MASK) {
394 if ((pa->e_perm & mask_obj->e_perm & want) == want)
395 return 0;
396 return -EACCES;
397 }
398 }
399
400check_perm:
401 if ((pa->e_perm & want) == want)
402 return 0;
403 return -EACCES;
404}
405
406/*
407 * Modify acl when creating a new inode. The caller must ensure the acl is
408 * only referenced once.
409 *
410 * mode_p initially must contain the mode parameter to the open() / creat()
411 * system calls. All permissions that are not granted by the acl are removed.
412 * The permissions in the acl are changed to reflect the mode_p parameter.
413 */
Al Virod3fb6122011-07-23 18:37:50 -0400414static int posix_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415{
416 struct posix_acl_entry *pa, *pe;
417 struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
Al Virod3fb6122011-07-23 18:37:50 -0400418 umode_t mode = *mode_p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419 int not_equiv = 0;
420
421 /* assert(atomic_read(acl->a_refcount) == 1); */
422
423 FOREACH_ACL_ENTRY(pa, acl, pe) {
424 switch(pa->e_tag) {
425 case ACL_USER_OBJ:
426 pa->e_perm &= (mode >> 6) | ~S_IRWXO;
427 mode &= (pa->e_perm << 6) | ~S_IRWXU;
428 break;
429
430 case ACL_USER:
431 case ACL_GROUP:
432 not_equiv = 1;
433 break;
434
435 case ACL_GROUP_OBJ:
436 group_obj = pa;
437 break;
438
439 case ACL_OTHER:
440 pa->e_perm &= mode | ~S_IRWXO;
441 mode &= pa->e_perm | ~S_IRWXO;
442 break;
443
444 case ACL_MASK:
445 mask_obj = pa;
446 not_equiv = 1;
447 break;
448
449 default:
450 return -EIO;
451 }
452 }
453
454 if (mask_obj) {
455 mask_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
456 mode &= (mask_obj->e_perm << 3) | ~S_IRWXG;
457 } else {
458 if (!group_obj)
459 return -EIO;
460 group_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
461 mode &= (group_obj->e_perm << 3) | ~S_IRWXG;
462 }
463
464 *mode_p = (*mode_p & ~S_IRWXUGO) | mode;
465 return not_equiv;
466}
467
468/*
469 * Modify the ACL for the chmod syscall.
470 */
Christoph Hellwig5bf32582013-12-20 05:16:41 -0800471static int __posix_acl_chmod_masq(struct posix_acl *acl, umode_t mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472{
473 struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
474 struct posix_acl_entry *pa, *pe;
475
476 /* assert(atomic_read(acl->a_refcount) == 1); */
477
478 FOREACH_ACL_ENTRY(pa, acl, pe) {
479 switch(pa->e_tag) {
480 case ACL_USER_OBJ:
481 pa->e_perm = (mode & S_IRWXU) >> 6;
482 break;
483
484 case ACL_USER:
485 case ACL_GROUP:
486 break;
487
488 case ACL_GROUP_OBJ:
489 group_obj = pa;
490 break;
491
492 case ACL_MASK:
493 mask_obj = pa;
494 break;
495
496 case ACL_OTHER:
497 pa->e_perm = (mode & S_IRWXO);
498 break;
499
500 default:
501 return -EIO;
502 }
503 }
504
505 if (mask_obj) {
506 mask_obj->e_perm = (mode & S_IRWXG) >> 3;
507 } else {
508 if (!group_obj)
509 return -EIO;
510 group_obj->e_perm = (mode & S_IRWXG) >> 3;
511 }
512
513 return 0;
514}
Al Virobc26ab52011-07-23 00:18:02 -0400515
516int
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800517__posix_acl_create(struct posix_acl **acl, gfp_t gfp, umode_t *mode_p)
Al Viro826cae22011-07-23 03:10:32 -0400518{
519 struct posix_acl *clone = posix_acl_clone(*acl, gfp);
520 int err = -ENOMEM;
521 if (clone) {
522 err = posix_acl_create_masq(clone, mode_p);
523 if (err < 0) {
524 posix_acl_release(clone);
525 clone = NULL;
526 }
527 }
528 posix_acl_release(*acl);
529 *acl = clone;
530 return err;
531}
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800532EXPORT_SYMBOL(__posix_acl_create);
Al Viro826cae22011-07-23 03:10:32 -0400533
534int
Christoph Hellwig5bf32582013-12-20 05:16:41 -0800535__posix_acl_chmod(struct posix_acl **acl, gfp_t gfp, umode_t mode)
Al Virobc26ab52011-07-23 00:18:02 -0400536{
537 struct posix_acl *clone = posix_acl_clone(*acl, gfp);
538 int err = -ENOMEM;
539 if (clone) {
Christoph Hellwig5bf32582013-12-20 05:16:41 -0800540 err = __posix_acl_chmod_masq(clone, mode);
Al Virobc26ab52011-07-23 00:18:02 -0400541 if (err) {
542 posix_acl_release(clone);
543 clone = NULL;
544 }
545 }
546 posix_acl_release(*acl);
547 *acl = clone;
548 return err;
549}
Christoph Hellwig5bf32582013-12-20 05:16:41 -0800550EXPORT_SYMBOL(__posix_acl_chmod);
551
552int
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800553posix_acl_chmod(struct inode *inode, umode_t mode)
Christoph Hellwig5bf32582013-12-20 05:16:41 -0800554{
555 struct posix_acl *acl;
556 int ret = 0;
557
558 if (!IS_POSIXACL(inode))
559 return 0;
560 if (!inode->i_op->set_acl)
561 return -EOPNOTSUPP;
562
563 acl = get_acl(inode, ACL_TYPE_ACCESS);
Trond Myklebust789b6632014-01-31 14:25:19 -0500564 if (IS_ERR_OR_NULL(acl)) {
565 if (acl == ERR_PTR(-EOPNOTSUPP))
566 return 0;
Christoph Hellwig5bf32582013-12-20 05:16:41 -0800567 return PTR_ERR(acl);
Trond Myklebust789b6632014-01-31 14:25:19 -0500568 }
Christoph Hellwig5bf32582013-12-20 05:16:41 -0800569
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800570 ret = __posix_acl_chmod(&acl, GFP_KERNEL, mode);
Christoph Hellwig5bf32582013-12-20 05:16:41 -0800571 if (ret)
572 return ret;
573 ret = inode->i_op->set_acl(inode, acl, ACL_TYPE_ACCESS);
574 posix_acl_release(acl);
575 return ret;
576}
Al Virobc26ab52011-07-23 00:18:02 -0400577EXPORT_SYMBOL(posix_acl_chmod);
Christoph Hellwig5c8ebd52013-12-20 05:16:37 -0800578
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800579int
580posix_acl_create(struct inode *dir, umode_t *mode,
581 struct posix_acl **default_acl, struct posix_acl **acl)
582{
583 struct posix_acl *p;
Dan Carpenterc0c3a712015-06-19 09:00:55 +1000584 struct posix_acl *clone;
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800585 int ret;
586
Dan Carpenterc0c3a712015-06-19 09:00:55 +1000587 *acl = NULL;
588 *default_acl = NULL;
589
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800590 if (S_ISLNK(*mode) || !IS_POSIXACL(dir))
Dan Carpenterc0c3a712015-06-19 09:00:55 +1000591 return 0;
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800592
593 p = get_acl(dir, ACL_TYPE_DEFAULT);
Dan Carpenterc0c3a712015-06-19 09:00:55 +1000594 if (!p || p == ERR_PTR(-EOPNOTSUPP)) {
595 *mode &= ~current_umask();
596 return 0;
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800597 }
Dan Carpenterc0c3a712015-06-19 09:00:55 +1000598 if (IS_ERR(p))
599 return PTR_ERR(p);
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800600
Miklos Szeredibeaf2262016-09-16 12:44:21 +0200601 ret = -ENOMEM;
Dan Carpenterc0c3a712015-06-19 09:00:55 +1000602 clone = posix_acl_clone(p, GFP_NOFS);
603 if (!clone)
Miklos Szeredibeaf2262016-09-16 12:44:21 +0200604 goto err_release;
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800605
Dan Carpenterc0c3a712015-06-19 09:00:55 +1000606 ret = posix_acl_create_masq(clone, mode);
Omar Sandovalfed0b582015-02-08 21:45:25 -0800607 if (ret < 0)
Miklos Szeredibeaf2262016-09-16 12:44:21 +0200608 goto err_release_clone;
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800609
Dan Carpenterc0c3a712015-06-19 09:00:55 +1000610 if (ret == 0)
611 posix_acl_release(clone);
612 else
613 *acl = clone;
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800614
Dan Carpenterc0c3a712015-06-19 09:00:55 +1000615 if (!S_ISDIR(*mode))
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800616 posix_acl_release(p);
Dan Carpenterc0c3a712015-06-19 09:00:55 +1000617 else
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800618 *default_acl = p;
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800619
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800620 return 0;
Omar Sandovalfed0b582015-02-08 21:45:25 -0800621
Miklos Szeredibeaf2262016-09-16 12:44:21 +0200622err_release_clone:
Dan Carpenterc0c3a712015-06-19 09:00:55 +1000623 posix_acl_release(clone);
Miklos Szeredibeaf2262016-09-16 12:44:21 +0200624err_release:
Omar Sandovalfed0b582015-02-08 21:45:25 -0800625 posix_acl_release(p);
Miklos Szeredibeaf2262016-09-16 12:44:21 +0200626 return ret;
Christoph Hellwig37bc1532013-12-20 05:16:42 -0800627}
628EXPORT_SYMBOL_GPL(posix_acl_create);
629
Jan Kara07393102016-09-19 17:39:09 +0200630/**
631 * posix_acl_update_mode - update mode in set_acl
632 *
633 * Update the file mode when setting an ACL: compute the new file permission
634 * bits based on the ACL. In addition, if the ACL is equivalent to the new
635 * file mode, set *acl to NULL to indicate that no ACL should be set.
636 *
637 * As with chmod, clear the setgit bit if the caller is not in the owning group
638 * or capable of CAP_FSETID (see inode_change_ok).
639 *
640 * Called from set_acl inode operations.
641 */
642int posix_acl_update_mode(struct inode *inode, umode_t *mode_p,
643 struct posix_acl **acl)
644{
645 umode_t mode = inode->i_mode;
646 int error;
647
648 error = posix_acl_equiv_mode(*acl, &mode);
649 if (error < 0)
650 return error;
651 if (error == 0)
652 *acl = NULL;
653 if (!in_group_p(inode->i_gid) &&
654 !capable_wrt_inode_uidgid(inode, CAP_FSETID))
655 mode &= ~S_ISGID;
656 *mode_p = mode;
657 return 0;
658}
659EXPORT_SYMBOL(posix_acl_update_mode);
660
Christoph Hellwig5c8ebd52013-12-20 05:16:37 -0800661/*
662 * Fix up the uids and gids in posix acl extended attributes in place.
663 */
664static void posix_acl_fix_xattr_userns(
665 struct user_namespace *to, struct user_namespace *from,
666 void *value, size_t size)
667{
Andreas Gruenbacher2211d5b2016-09-27 13:03:22 +0200668 struct posix_acl_xattr_header *header = value;
669 struct posix_acl_xattr_entry *entry = (void *)(header + 1), *end;
Christoph Hellwig5c8ebd52013-12-20 05:16:37 -0800670 int count;
671 kuid_t uid;
672 kgid_t gid;
673
674 if (!value)
675 return;
Andreas Gruenbacher2211d5b2016-09-27 13:03:22 +0200676 if (size < sizeof(struct posix_acl_xattr_header))
Christoph Hellwig5c8ebd52013-12-20 05:16:37 -0800677 return;
678 if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
679 return;
680
681 count = posix_acl_xattr_count(size);
682 if (count < 0)
683 return;
684 if (count == 0)
685 return;
686
687 for (end = entry + count; entry != end; entry++) {
688 switch(le16_to_cpu(entry->e_tag)) {
689 case ACL_USER:
690 uid = make_kuid(from, le32_to_cpu(entry->e_id));
691 entry->e_id = cpu_to_le32(from_kuid(to, uid));
692 break;
693 case ACL_GROUP:
694 gid = make_kgid(from, le32_to_cpu(entry->e_id));
695 entry->e_id = cpu_to_le32(from_kgid(to, gid));
696 break;
697 default:
698 break;
699 }
700 }
701}
702
703void posix_acl_fix_xattr_from_user(void *value, size_t size)
704{
705 struct user_namespace *user_ns = current_user_ns();
706 if (user_ns == &init_user_ns)
707 return;
708 posix_acl_fix_xattr_userns(&init_user_ns, user_ns, value, size);
709}
710
711void posix_acl_fix_xattr_to_user(void *value, size_t size)
712{
713 struct user_namespace *user_ns = current_user_ns();
714 if (user_ns == &init_user_ns)
715 return;
716 posix_acl_fix_xattr_userns(user_ns, &init_user_ns, value, size);
717}
718
719/*
720 * Convert from extended attribute to in-memory representation.
721 */
722struct posix_acl *
723posix_acl_from_xattr(struct user_namespace *user_ns,
724 const void *value, size_t size)
725{
Andreas Gruenbacher2211d5b2016-09-27 13:03:22 +0200726 const struct posix_acl_xattr_header *header = value;
727 const struct posix_acl_xattr_entry *entry = (const void *)(header + 1), *end;
Christoph Hellwig5c8ebd52013-12-20 05:16:37 -0800728 int count;
729 struct posix_acl *acl;
730 struct posix_acl_entry *acl_e;
731
732 if (!value)
733 return NULL;
Andreas Gruenbacher2211d5b2016-09-27 13:03:22 +0200734 if (size < sizeof(struct posix_acl_xattr_header))
Christoph Hellwig5c8ebd52013-12-20 05:16:37 -0800735 return ERR_PTR(-EINVAL);
736 if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
737 return ERR_PTR(-EOPNOTSUPP);
738
739 count = posix_acl_xattr_count(size);
740 if (count < 0)
741 return ERR_PTR(-EINVAL);
742 if (count == 0)
743 return NULL;
744
745 acl = posix_acl_alloc(count, GFP_NOFS);
746 if (!acl)
747 return ERR_PTR(-ENOMEM);
748 acl_e = acl->a_entries;
749
750 for (end = entry + count; entry != end; acl_e++, entry++) {
751 acl_e->e_tag = le16_to_cpu(entry->e_tag);
752 acl_e->e_perm = le16_to_cpu(entry->e_perm);
753
754 switch(acl_e->e_tag) {
755 case ACL_USER_OBJ:
756 case ACL_GROUP_OBJ:
757 case ACL_MASK:
758 case ACL_OTHER:
759 break;
760
761 case ACL_USER:
762 acl_e->e_uid =
763 make_kuid(user_ns,
764 le32_to_cpu(entry->e_id));
765 if (!uid_valid(acl_e->e_uid))
766 goto fail;
767 break;
768 case ACL_GROUP:
769 acl_e->e_gid =
770 make_kgid(user_ns,
771 le32_to_cpu(entry->e_id));
772 if (!gid_valid(acl_e->e_gid))
773 goto fail;
774 break;
775
776 default:
777 goto fail;
778 }
779 }
780 return acl;
781
782fail:
783 posix_acl_release(acl);
784 return ERR_PTR(-EINVAL);
785}
786EXPORT_SYMBOL (posix_acl_from_xattr);
787
788/*
789 * Convert from in-memory to extended attribute representation.
790 */
791int
792posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl,
793 void *buffer, size_t size)
794{
Andreas Gruenbacher2211d5b2016-09-27 13:03:22 +0200795 struct posix_acl_xattr_header *ext_acl = buffer;
796 struct posix_acl_xattr_entry *ext_entry;
Christoph Hellwig5c8ebd52013-12-20 05:16:37 -0800797 int real_size, n;
798
799 real_size = posix_acl_xattr_size(acl->a_count);
800 if (!buffer)
801 return real_size;
802 if (real_size > size)
803 return -ERANGE;
Dan Carpenter47ba9732014-02-14 12:05:49 +0300804
Andreas Gruenbacher2211d5b2016-09-27 13:03:22 +0200805 ext_entry = (void *)(ext_acl + 1);
Christoph Hellwig5c8ebd52013-12-20 05:16:37 -0800806 ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);
807
808 for (n=0; n < acl->a_count; n++, ext_entry++) {
809 const struct posix_acl_entry *acl_e = &acl->a_entries[n];
810 ext_entry->e_tag = cpu_to_le16(acl_e->e_tag);
811 ext_entry->e_perm = cpu_to_le16(acl_e->e_perm);
812 switch(acl_e->e_tag) {
813 case ACL_USER:
814 ext_entry->e_id =
815 cpu_to_le32(from_kuid(user_ns, acl_e->e_uid));
816 break;
817 case ACL_GROUP:
818 ext_entry->e_id =
819 cpu_to_le32(from_kgid(user_ns, acl_e->e_gid));
820 break;
821 default:
822 ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID);
823 break;
824 }
825 }
826 return real_size;
827}
828EXPORT_SYMBOL (posix_acl_to_xattr);
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800829
830static int
Andreas Gruenbacherd9a82a02015-10-04 19:18:51 +0200831posix_acl_xattr_get(const struct xattr_handler *handler,
Al Virob2968212016-04-10 20:48:24 -0400832 struct dentry *unused, struct inode *inode,
833 const char *name, void *value, size_t size)
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800834{
835 struct posix_acl *acl;
836 int error;
837
Al Virob2968212016-04-10 20:48:24 -0400838 if (!IS_POSIXACL(inode))
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800839 return -EOPNOTSUPP;
Al Virob2968212016-04-10 20:48:24 -0400840 if (S_ISLNK(inode->i_mode))
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800841 return -EOPNOTSUPP;
842
Al Virob2968212016-04-10 20:48:24 -0400843 acl = get_acl(inode, handler->flags);
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800844 if (IS_ERR(acl))
845 return PTR_ERR(acl);
846 if (acl == NULL)
847 return -ENODATA;
848
849 error = posix_acl_to_xattr(&init_user_ns, acl, value, size);
850 posix_acl_release(acl);
851
852 return error;
853}
854
Andreas Gruenbacher485e71e2016-06-22 23:57:25 +0200855int
856set_posix_acl(struct inode *inode, int type, struct posix_acl *acl)
857{
858 if (!IS_POSIXACL(inode))
859 return -EOPNOTSUPP;
860 if (!inode->i_op->set_acl)
861 return -EOPNOTSUPP;
862
863 if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
864 return acl ? -EACCES : 0;
865 if (!inode_owner_or_capable(inode))
866 return -EPERM;
867
868 if (acl) {
Linus Torvaldsa867d732016-07-29 15:54:19 -0700869 int ret = posix_acl_valid(inode->i_sb->s_user_ns, acl);
Andreas Gruenbacher485e71e2016-06-22 23:57:25 +0200870 if (ret)
871 return ret;
872 }
873 return inode->i_op->set_acl(inode, acl, type);
874}
875EXPORT_SYMBOL(set_posix_acl);
876
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800877static int
Andreas Gruenbacherd9a82a02015-10-04 19:18:51 +0200878posix_acl_xattr_set(const struct xattr_handler *handler,
Al Viro59301222016-05-27 10:19:30 -0400879 struct dentry *unused, struct inode *inode,
880 const char *name, const void *value,
881 size_t size, int flags)
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800882{
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800883 struct posix_acl *acl = NULL;
884 int ret;
885
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800886 if (value) {
887 acl = posix_acl_from_xattr(&init_user_ns, value, size);
888 if (IS_ERR(acl))
889 return PTR_ERR(acl);
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800890 }
Andreas Gruenbacher485e71e2016-06-22 23:57:25 +0200891 ret = set_posix_acl(inode, handler->flags, acl);
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800892 posix_acl_release(acl);
893 return ret;
894}
895
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100896static bool
897posix_acl_xattr_list(struct dentry *dentry)
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800898{
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100899 return IS_POSIXACL(d_backing_inode(dentry));
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800900}
901
902const struct xattr_handler posix_acl_access_xattr_handler = {
Andreas Gruenbacher98e9cb52015-12-02 14:44:36 +0100903 .name = XATTR_NAME_POSIX_ACL_ACCESS,
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800904 .flags = ACL_TYPE_ACCESS,
905 .list = posix_acl_xattr_list,
906 .get = posix_acl_xattr_get,
907 .set = posix_acl_xattr_set,
908};
909EXPORT_SYMBOL_GPL(posix_acl_access_xattr_handler);
910
911const struct xattr_handler posix_acl_default_xattr_handler = {
Andreas Gruenbacher98e9cb52015-12-02 14:44:36 +0100912 .name = XATTR_NAME_POSIX_ACL_DEFAULT,
Christoph Hellwig2aeccbe2013-12-20 05:16:40 -0800913 .flags = ACL_TYPE_DEFAULT,
914 .list = posix_acl_xattr_list,
915 .get = posix_acl_xattr_get,
916 .set = posix_acl_xattr_set,
917};
918EXPORT_SYMBOL_GPL(posix_acl_default_xattr_handler);
Christoph Hellwigfeda8212013-12-20 05:16:54 -0800919
920int simple_set_acl(struct inode *inode, struct posix_acl *acl, int type)
921{
922 int error;
923
924 if (type == ACL_TYPE_ACCESS) {
925 error = posix_acl_equiv_mode(acl, &inode->i_mode);
926 if (error < 0)
927 return 0;
928 if (error == 0)
929 acl = NULL;
930 }
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}