Commit | Line | Data |
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457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 | 2 | /* |
5c8ebd57 | 3 | * Copyright (C) 2002,2003 by Andreas Gruenbacher <a.gruenbacher@computer.org> |
1da177e4 | 4 | * |
5c8ebd57 CH |
5 | * Fixes from William Schumacher incorporated on 15 March 2001. |
6 | * (Reported by Charles Bertsch, <CBertsch@microtest.com>). | |
1da177e4 LT |
7 | */ |
8 | ||
9 | /* | |
10 | * This file contains generic functions for manipulating | |
11 | * POSIX 1003.1e draft standard 17 ACLs. | |
12 | */ | |
13 | ||
14 | #include <linux/kernel.h> | |
15 | #include <linux/slab.h> | |
60063497 | 16 | #include <linux/atomic.h> |
1da177e4 LT |
17 | #include <linux/fs.h> |
18 | #include <linux/sched.h> | |
5b825c3a | 19 | #include <linux/cred.h> |
1da177e4 | 20 | #include <linux/posix_acl.h> |
5c8ebd57 | 21 | #include <linux/posix_acl_xattr.h> |
2aeccbe9 | 22 | #include <linux/xattr.h> |
630d9c47 | 23 | #include <linux/export.h> |
5c8ebd57 | 24 | #include <linux/user_namespace.h> |
332f606b | 25 | #include <linux/namei.h> |
a793d79e | 26 | #include <linux/mnt_idmapping.h> |
36f05cab | 27 | #include <linux/iversion.h> |
1da177e4 | 28 | |
04c57f45 | 29 | static struct posix_acl **acl_by_type(struct inode *inode, int type) |
0afaa120 AM |
30 | { |
31 | switch (type) { | |
32 | case ACL_TYPE_ACCESS: | |
33 | return &inode->i_acl; | |
34 | case ACL_TYPE_DEFAULT: | |
35 | return &inode->i_default_acl; | |
36 | default: | |
37 | BUG(); | |
38 | } | |
39 | } | |
0afaa120 AM |
40 | |
41 | struct posix_acl *get_cached_acl(struct inode *inode, int type) | |
42 | { | |
43 | struct posix_acl **p = acl_by_type(inode, type); | |
b8a7a3a6 AG |
44 | struct posix_acl *acl; |
45 | ||
46 | for (;;) { | |
47 | rcu_read_lock(); | |
48 | acl = rcu_dereference(*p); | |
49 | if (!acl || is_uncached_acl(acl) || | |
66717260 | 50 | refcount_inc_not_zero(&acl->a_refcount)) |
b8a7a3a6 AG |
51 | break; |
52 | rcu_read_unlock(); | |
53 | cpu_relax(); | |
0afaa120 | 54 | } |
b8a7a3a6 | 55 | rcu_read_unlock(); |
0afaa120 AM |
56 | return acl; |
57 | } | |
58 | EXPORT_SYMBOL(get_cached_acl); | |
59 | ||
60 | struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type) | |
61 | { | |
332f606b MS |
62 | struct posix_acl *acl = rcu_dereference(*acl_by_type(inode, type)); |
63 | ||
64 | if (acl == ACL_DONT_CACHE) { | |
65 | struct posix_acl *ret; | |
66 | ||
67 | ret = inode->i_op->get_acl(inode, type, LOOKUP_RCU); | |
68 | if (!IS_ERR(ret)) | |
69 | acl = ret; | |
70 | } | |
71 | ||
72 | return acl; | |
0afaa120 AM |
73 | } |
74 | EXPORT_SYMBOL(get_cached_acl_rcu); | |
75 | ||
76 | void set_cached_acl(struct inode *inode, int type, struct posix_acl *acl) | |
77 | { | |
78 | struct posix_acl **p = acl_by_type(inode, type); | |
79 | struct posix_acl *old; | |
b8a7a3a6 AG |
80 | |
81 | old = xchg(p, posix_acl_dup(acl)); | |
82 | if (!is_uncached_acl(old)) | |
0afaa120 AM |
83 | posix_acl_release(old); |
84 | } | |
85 | EXPORT_SYMBOL(set_cached_acl); | |
86 | ||
b8a7a3a6 | 87 | static void __forget_cached_acl(struct posix_acl **p) |
0afaa120 | 88 | { |
0afaa120 | 89 | struct posix_acl *old; |
b8a7a3a6 AG |
90 | |
91 | old = xchg(p, ACL_NOT_CACHED); | |
92 | if (!is_uncached_acl(old)) | |
0afaa120 AM |
93 | posix_acl_release(old); |
94 | } | |
b8a7a3a6 AG |
95 | |
96 | void forget_cached_acl(struct inode *inode, int type) | |
97 | { | |
98 | __forget_cached_acl(acl_by_type(inode, type)); | |
99 | } | |
0afaa120 AM |
100 | EXPORT_SYMBOL(forget_cached_acl); |
101 | ||
102 | void forget_all_cached_acls(struct inode *inode) | |
103 | { | |
b8a7a3a6 AG |
104 | __forget_cached_acl(&inode->i_acl); |
105 | __forget_cached_acl(&inode->i_default_acl); | |
0afaa120 AM |
106 | } |
107 | EXPORT_SYMBOL(forget_all_cached_acls); | |
1da177e4 | 108 | |
2982baa2 CH |
109 | struct posix_acl *get_acl(struct inode *inode, int type) |
110 | { | |
b8a7a3a6 AG |
111 | void *sentinel; |
112 | struct posix_acl **p; | |
2982baa2 CH |
113 | struct posix_acl *acl; |
114 | ||
b8a7a3a6 AG |
115 | /* |
116 | * The sentinel is used to detect when another operation like | |
117 | * set_cached_acl() or forget_cached_acl() races with get_acl(). | |
118 | * It is guaranteed that is_uncached_acl(sentinel) is true. | |
119 | */ | |
120 | ||
2982baa2 | 121 | acl = get_cached_acl(inode, type); |
b8a7a3a6 | 122 | if (!is_uncached_acl(acl)) |
2982baa2 CH |
123 | return acl; |
124 | ||
125 | if (!IS_POSIXACL(inode)) | |
126 | return NULL; | |
127 | ||
b8a7a3a6 AG |
128 | sentinel = uncached_acl_sentinel(current); |
129 | p = acl_by_type(inode, type); | |
130 | ||
131 | /* | |
132 | * If the ACL isn't being read yet, set our sentinel. Otherwise, the | |
133 | * current value of the ACL will not be ACL_NOT_CACHED and so our own | |
134 | * sentinel will not be set; another task will update the cache. We | |
135 | * could wait for that other task to complete its job, but it's easier | |
136 | * to just call ->get_acl to fetch the ACL ourself. (This is going to | |
137 | * be an unlikely race.) | |
138 | */ | |
d1cef29a | 139 | cmpxchg(p, ACL_NOT_CACHED, sentinel); |
b8a7a3a6 | 140 | |
2982baa2 | 141 | /* |
b8a7a3a6 AG |
142 | * Normally, the ACL returned by ->get_acl will be cached. |
143 | * A filesystem can prevent that by calling | |
144 | * forget_cached_acl(inode, type) in ->get_acl. | |
2982baa2 CH |
145 | * |
146 | * If the filesystem doesn't have a get_acl() function at all, we'll | |
147 | * just create the negative cache entry. | |
148 | */ | |
149 | if (!inode->i_op->get_acl) { | |
150 | set_cached_acl(inode, type, NULL); | |
151 | return NULL; | |
152 | } | |
0cad6246 | 153 | acl = inode->i_op->get_acl(inode, type, false); |
b8a7a3a6 AG |
154 | |
155 | if (IS_ERR(acl)) { | |
156 | /* | |
157 | * Remove our sentinel so that we don't block future attempts | |
158 | * to cache the ACL. | |
159 | */ | |
160 | cmpxchg(p, sentinel, ACL_NOT_CACHED); | |
161 | return acl; | |
162 | } | |
163 | ||
164 | /* | |
165 | * Cache the result, but only if our sentinel is still in place. | |
166 | */ | |
167 | posix_acl_dup(acl); | |
168 | if (unlikely(cmpxchg(p, sentinel, acl) != sentinel)) | |
169 | posix_acl_release(acl); | |
170 | return acl; | |
2982baa2 CH |
171 | } |
172 | EXPORT_SYMBOL(get_acl); | |
173 | ||
f61f6da0 CL |
174 | /* |
175 | * Init a fresh posix_acl | |
176 | */ | |
177 | void | |
178 | posix_acl_init(struct posix_acl *acl, int count) | |
179 | { | |
66717260 | 180 | refcount_set(&acl->a_refcount, 1); |
f61f6da0 CL |
181 | acl->a_count = count; |
182 | } | |
0afaa120 | 183 | EXPORT_SYMBOL(posix_acl_init); |
f61f6da0 | 184 | |
1da177e4 LT |
185 | /* |
186 | * Allocate a new ACL with the specified number of entries. | |
187 | */ | |
188 | struct posix_acl * | |
dd0fc66f | 189 | posix_acl_alloc(int count, gfp_t flags) |
1da177e4 LT |
190 | { |
191 | const size_t size = sizeof(struct posix_acl) + | |
192 | count * sizeof(struct posix_acl_entry); | |
193 | struct posix_acl *acl = kmalloc(size, flags); | |
f61f6da0 CL |
194 | if (acl) |
195 | posix_acl_init(acl, count); | |
1da177e4 LT |
196 | return acl; |
197 | } | |
0afaa120 | 198 | EXPORT_SYMBOL(posix_acl_alloc); |
1da177e4 LT |
199 | |
200 | /* | |
201 | * Clone an ACL. | |
202 | */ | |
8043bffd | 203 | struct posix_acl * |
dd0fc66f | 204 | posix_acl_clone(const struct posix_acl *acl, gfp_t flags) |
1da177e4 LT |
205 | { |
206 | struct posix_acl *clone = NULL; | |
207 | ||
208 | if (acl) { | |
209 | int size = sizeof(struct posix_acl) + acl->a_count * | |
210 | sizeof(struct posix_acl_entry); | |
52978be6 AD |
211 | clone = kmemdup(acl, size, flags); |
212 | if (clone) | |
66717260 | 213 | refcount_set(&clone->a_refcount, 1); |
1da177e4 LT |
214 | } |
215 | return clone; | |
216 | } | |
8043bffd | 217 | EXPORT_SYMBOL_GPL(posix_acl_clone); |
1da177e4 LT |
218 | |
219 | /* | |
220 | * Check if an acl is valid. Returns 0 if it is, or -E... otherwise. | |
221 | */ | |
222 | int | |
0d4d717f | 223 | posix_acl_valid(struct user_namespace *user_ns, const struct posix_acl *acl) |
1da177e4 LT |
224 | { |
225 | const struct posix_acl_entry *pa, *pe; | |
226 | int state = ACL_USER_OBJ; | |
1da177e4 LT |
227 | int needs_mask = 0; |
228 | ||
229 | FOREACH_ACL_ENTRY(pa, acl, pe) { | |
230 | if (pa->e_perm & ~(ACL_READ|ACL_WRITE|ACL_EXECUTE)) | |
231 | return -EINVAL; | |
232 | switch (pa->e_tag) { | |
233 | case ACL_USER_OBJ: | |
234 | if (state == ACL_USER_OBJ) { | |
1da177e4 LT |
235 | state = ACL_USER; |
236 | break; | |
237 | } | |
238 | return -EINVAL; | |
239 | ||
240 | case ACL_USER: | |
241 | if (state != ACL_USER) | |
242 | return -EINVAL; | |
0d4d717f | 243 | if (!kuid_has_mapping(user_ns, pa->e_uid)) |
1da177e4 | 244 | return -EINVAL; |
1da177e4 LT |
245 | needs_mask = 1; |
246 | break; | |
247 | ||
248 | case ACL_GROUP_OBJ: | |
249 | if (state == ACL_USER) { | |
1da177e4 LT |
250 | state = ACL_GROUP; |
251 | break; | |
252 | } | |
253 | return -EINVAL; | |
254 | ||
255 | case ACL_GROUP: | |
256 | if (state != ACL_GROUP) | |
257 | return -EINVAL; | |
0d4d717f | 258 | if (!kgid_has_mapping(user_ns, pa->e_gid)) |
2f6f0654 | 259 | return -EINVAL; |
1da177e4 LT |
260 | needs_mask = 1; |
261 | break; | |
262 | ||
263 | case ACL_MASK: | |
264 | if (state != ACL_GROUP) | |
265 | return -EINVAL; | |
266 | state = ACL_OTHER; | |
267 | break; | |
268 | ||
269 | case ACL_OTHER: | |
270 | if (state == ACL_OTHER || | |
271 | (state == ACL_GROUP && !needs_mask)) { | |
272 | state = 0; | |
273 | break; | |
274 | } | |
275 | return -EINVAL; | |
276 | ||
277 | default: | |
278 | return -EINVAL; | |
279 | } | |
280 | } | |
281 | if (state == 0) | |
282 | return 0; | |
283 | return -EINVAL; | |
284 | } | |
0afaa120 | 285 | EXPORT_SYMBOL(posix_acl_valid); |
1da177e4 LT |
286 | |
287 | /* | |
288 | * Returns 0 if the acl can be exactly represented in the traditional | |
289 | * file mode permission bits, or else 1. Returns -E... on error. | |
290 | */ | |
291 | int | |
d6952123 | 292 | posix_acl_equiv_mode(const struct posix_acl *acl, umode_t *mode_p) |
1da177e4 LT |
293 | { |
294 | const struct posix_acl_entry *pa, *pe; | |
d6952123 | 295 | umode_t mode = 0; |
1da177e4 LT |
296 | int not_equiv = 0; |
297 | ||
50c6e282 CH |
298 | /* |
299 | * A null ACL can always be presented as mode bits. | |
300 | */ | |
301 | if (!acl) | |
302 | return 0; | |
303 | ||
1da177e4 LT |
304 | FOREACH_ACL_ENTRY(pa, acl, pe) { |
305 | switch (pa->e_tag) { | |
306 | case ACL_USER_OBJ: | |
307 | mode |= (pa->e_perm & S_IRWXO) << 6; | |
308 | break; | |
309 | case ACL_GROUP_OBJ: | |
310 | mode |= (pa->e_perm & S_IRWXO) << 3; | |
311 | break; | |
312 | case ACL_OTHER: | |
313 | mode |= pa->e_perm & S_IRWXO; | |
314 | break; | |
315 | case ACL_MASK: | |
316 | mode = (mode & ~S_IRWXG) | | |
317 | ((pa->e_perm & S_IRWXO) << 3); | |
318 | not_equiv = 1; | |
319 | break; | |
320 | case ACL_USER: | |
321 | case ACL_GROUP: | |
322 | not_equiv = 1; | |
323 | break; | |
324 | default: | |
325 | return -EINVAL; | |
326 | } | |
327 | } | |
328 | if (mode_p) | |
329 | *mode_p = (*mode_p & ~S_IRWXUGO) | mode; | |
330 | return not_equiv; | |
331 | } | |
0afaa120 | 332 | EXPORT_SYMBOL(posix_acl_equiv_mode); |
1da177e4 LT |
333 | |
334 | /* | |
335 | * Create an ACL representing the file mode permission bits of an inode. | |
336 | */ | |
337 | struct posix_acl * | |
3a5fba19 | 338 | posix_acl_from_mode(umode_t mode, gfp_t flags) |
1da177e4 LT |
339 | { |
340 | struct posix_acl *acl = posix_acl_alloc(3, flags); | |
341 | if (!acl) | |
342 | return ERR_PTR(-ENOMEM); | |
343 | ||
344 | acl->a_entries[0].e_tag = ACL_USER_OBJ; | |
1da177e4 LT |
345 | acl->a_entries[0].e_perm = (mode & S_IRWXU) >> 6; |
346 | ||
347 | acl->a_entries[1].e_tag = ACL_GROUP_OBJ; | |
1da177e4 LT |
348 | acl->a_entries[1].e_perm = (mode & S_IRWXG) >> 3; |
349 | ||
350 | acl->a_entries[2].e_tag = ACL_OTHER; | |
1da177e4 LT |
351 | acl->a_entries[2].e_perm = (mode & S_IRWXO); |
352 | return acl; | |
353 | } | |
0afaa120 | 354 | EXPORT_SYMBOL(posix_acl_from_mode); |
1da177e4 LT |
355 | |
356 | /* | |
357 | * Return 0 if current is granted want access to the inode | |
358 | * by the acl. Returns -E... otherwise. | |
359 | */ | |
360 | int | |
47291baa CB |
361 | posix_acl_permission(struct user_namespace *mnt_userns, struct inode *inode, |
362 | const struct posix_acl *acl, int want) | |
1da177e4 LT |
363 | { |
364 | const struct posix_acl_entry *pa, *pe, *mask_obj; | |
abfcf55d | 365 | struct user_namespace *fs_userns = i_user_ns(inode); |
1da177e4 | 366 | int found = 0; |
e933c15f CB |
367 | vfsuid_t vfsuid; |
368 | vfsgid_t vfsgid; | |
1da177e4 | 369 | |
63d72b93 | 370 | want &= MAY_READ | MAY_WRITE | MAY_EXEC; |
d124b60a | 371 | |
1da177e4 LT |
372 | FOREACH_ACL_ENTRY(pa, acl, pe) { |
373 | switch(pa->e_tag) { | |
374 | case ACL_USER_OBJ: | |
375 | /* (May have been checked already) */ | |
e933c15f CB |
376 | vfsuid = i_uid_into_vfsuid(mnt_userns, inode); |
377 | if (vfsuid_eq_kuid(vfsuid, current_fsuid())) | |
1da177e4 LT |
378 | goto check_perm; |
379 | break; | |
380 | case ACL_USER: | |
abfcf55d | 381 | vfsuid = make_vfsuid(mnt_userns, fs_userns, |
bd303368 | 382 | pa->e_uid); |
e933c15f | 383 | if (vfsuid_eq_kuid(vfsuid, current_fsuid())) |
1da177e4 LT |
384 | goto mask; |
385 | break; | |
386 | case ACL_GROUP_OBJ: | |
e933c15f CB |
387 | vfsgid = i_gid_into_vfsgid(mnt_userns, inode); |
388 | if (vfsgid_in_group_p(vfsgid)) { | |
1da177e4 LT |
389 | found = 1; |
390 | if ((pa->e_perm & want) == want) | |
391 | goto mask; | |
392 | } | |
393 | break; | |
394 | case ACL_GROUP: | |
abfcf55d | 395 | vfsgid = make_vfsgid(mnt_userns, fs_userns, |
bd303368 | 396 | pa->e_gid); |
e933c15f | 397 | if (vfsgid_in_group_p(vfsgid)) { |
1da177e4 LT |
398 | found = 1; |
399 | if ((pa->e_perm & want) == want) | |
400 | goto mask; | |
401 | } | |
402 | break; | |
403 | case ACL_MASK: | |
404 | break; | |
405 | case ACL_OTHER: | |
406 | if (found) | |
407 | return -EACCES; | |
408 | else | |
409 | goto check_perm; | |
410 | default: | |
411 | return -EIO; | |
412 | } | |
413 | } | |
414 | return -EIO; | |
415 | ||
416 | mask: | |
417 | for (mask_obj = pa+1; mask_obj != pe; mask_obj++) { | |
418 | if (mask_obj->e_tag == ACL_MASK) { | |
419 | if ((pa->e_perm & mask_obj->e_perm & want) == want) | |
420 | return 0; | |
421 | return -EACCES; | |
422 | } | |
423 | } | |
424 | ||
425 | check_perm: | |
426 | if ((pa->e_perm & want) == want) | |
427 | return 0; | |
428 | return -EACCES; | |
429 | } | |
430 | ||
431 | /* | |
432 | * Modify acl when creating a new inode. The caller must ensure the acl is | |
433 | * only referenced once. | |
434 | * | |
435 | * mode_p initially must contain the mode parameter to the open() / creat() | |
436 | * system calls. All permissions that are not granted by the acl are removed. | |
437 | * The permissions in the acl are changed to reflect the mode_p parameter. | |
438 | */ | |
d3fb6120 | 439 | static int posix_acl_create_masq(struct posix_acl *acl, umode_t *mode_p) |
1da177e4 LT |
440 | { |
441 | struct posix_acl_entry *pa, *pe; | |
442 | struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL; | |
d3fb6120 | 443 | umode_t mode = *mode_p; |
1da177e4 LT |
444 | int not_equiv = 0; |
445 | ||
446 | /* assert(atomic_read(acl->a_refcount) == 1); */ | |
447 | ||
448 | FOREACH_ACL_ENTRY(pa, acl, pe) { | |
449 | switch(pa->e_tag) { | |
450 | case ACL_USER_OBJ: | |
451 | pa->e_perm &= (mode >> 6) | ~S_IRWXO; | |
452 | mode &= (pa->e_perm << 6) | ~S_IRWXU; | |
453 | break; | |
454 | ||
455 | case ACL_USER: | |
456 | case ACL_GROUP: | |
457 | not_equiv = 1; | |
458 | break; | |
459 | ||
460 | case ACL_GROUP_OBJ: | |
461 | group_obj = pa; | |
462 | break; | |
463 | ||
464 | case ACL_OTHER: | |
465 | pa->e_perm &= mode | ~S_IRWXO; | |
466 | mode &= pa->e_perm | ~S_IRWXO; | |
467 | break; | |
468 | ||
469 | case ACL_MASK: | |
470 | mask_obj = pa; | |
471 | not_equiv = 1; | |
472 | break; | |
473 | ||
474 | default: | |
475 | return -EIO; | |
476 | } | |
477 | } | |
478 | ||
479 | if (mask_obj) { | |
480 | mask_obj->e_perm &= (mode >> 3) | ~S_IRWXO; | |
481 | mode &= (mask_obj->e_perm << 3) | ~S_IRWXG; | |
482 | } else { | |
483 | if (!group_obj) | |
484 | return -EIO; | |
485 | group_obj->e_perm &= (mode >> 3) | ~S_IRWXO; | |
486 | mode &= (group_obj->e_perm << 3) | ~S_IRWXG; | |
487 | } | |
488 | ||
489 | *mode_p = (*mode_p & ~S_IRWXUGO) | mode; | |
490 | return not_equiv; | |
491 | } | |
492 | ||
493 | /* | |
494 | * Modify the ACL for the chmod syscall. | |
495 | */ | |
5bf3258f | 496 | static int __posix_acl_chmod_masq(struct posix_acl *acl, umode_t mode) |
1da177e4 LT |
497 | { |
498 | struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL; | |
499 | struct posix_acl_entry *pa, *pe; | |
500 | ||
501 | /* assert(atomic_read(acl->a_refcount) == 1); */ | |
502 | ||
503 | FOREACH_ACL_ENTRY(pa, acl, pe) { | |
504 | switch(pa->e_tag) { | |
505 | case ACL_USER_OBJ: | |
506 | pa->e_perm = (mode & S_IRWXU) >> 6; | |
507 | break; | |
508 | ||
509 | case ACL_USER: | |
510 | case ACL_GROUP: | |
511 | break; | |
512 | ||
513 | case ACL_GROUP_OBJ: | |
514 | group_obj = pa; | |
515 | break; | |
516 | ||
517 | case ACL_MASK: | |
518 | mask_obj = pa; | |
519 | break; | |
520 | ||
521 | case ACL_OTHER: | |
522 | pa->e_perm = (mode & S_IRWXO); | |
523 | break; | |
524 | ||
525 | default: | |
526 | return -EIO; | |
527 | } | |
528 | } | |
529 | ||
530 | if (mask_obj) { | |
531 | mask_obj->e_perm = (mode & S_IRWXG) >> 3; | |
532 | } else { | |
533 | if (!group_obj) | |
534 | return -EIO; | |
535 | group_obj->e_perm = (mode & S_IRWXG) >> 3; | |
536 | } | |
537 | ||
538 | return 0; | |
539 | } | |
bc26ab5f | 540 | |
826cae2f | 541 | int |
37bc1539 | 542 | __posix_acl_create(struct posix_acl **acl, gfp_t gfp, umode_t *mode_p) |
826cae2f AV |
543 | { |
544 | struct posix_acl *clone = posix_acl_clone(*acl, gfp); | |
545 | int err = -ENOMEM; | |
546 | if (clone) { | |
547 | err = posix_acl_create_masq(clone, mode_p); | |
548 | if (err < 0) { | |
549 | posix_acl_release(clone); | |
550 | clone = NULL; | |
551 | } | |
552 | } | |
553 | posix_acl_release(*acl); | |
554 | *acl = clone; | |
555 | return err; | |
556 | } | |
37bc1539 | 557 | EXPORT_SYMBOL(__posix_acl_create); |
826cae2f | 558 | |
bc26ab5f | 559 | int |
5bf3258f | 560 | __posix_acl_chmod(struct posix_acl **acl, gfp_t gfp, umode_t mode) |
bc26ab5f AV |
561 | { |
562 | struct posix_acl *clone = posix_acl_clone(*acl, gfp); | |
563 | int err = -ENOMEM; | |
564 | if (clone) { | |
5bf3258f | 565 | err = __posix_acl_chmod_masq(clone, mode); |
bc26ab5f AV |
566 | if (err) { |
567 | posix_acl_release(clone); | |
568 | clone = NULL; | |
569 | } | |
570 | } | |
571 | posix_acl_release(*acl); | |
572 | *acl = clone; | |
573 | return err; | |
574 | } | |
5bf3258f CH |
575 | EXPORT_SYMBOL(__posix_acl_chmod); |
576 | ||
e65ce2a5 CB |
577 | /** |
578 | * posix_acl_chmod - chmod a posix acl | |
579 | * | |
580 | * @mnt_userns: user namespace of the mount @inode was found from | |
581 | * @inode: inode to check permissions on | |
582 | * @mode: the new mode of @inode | |
583 | * | |
584 | * If the inode has been found through an idmapped mount the user namespace of | |
585 | * the vfsmount must be passed through @mnt_userns. This function will then | |
586 | * take care to map the inode according to @mnt_userns before checking | |
587 | * permissions. On non-idmapped mounts or if permission checking is to be | |
588 | * performed on the raw inode simply passs init_user_ns. | |
589 | */ | |
5bf3258f | 590 | int |
e65ce2a5 CB |
591 | posix_acl_chmod(struct user_namespace *mnt_userns, struct inode *inode, |
592 | umode_t mode) | |
5bf3258f CH |
593 | { |
594 | struct posix_acl *acl; | |
595 | int ret = 0; | |
596 | ||
597 | if (!IS_POSIXACL(inode)) | |
598 | return 0; | |
599 | if (!inode->i_op->set_acl) | |
600 | return -EOPNOTSUPP; | |
601 | ||
602 | acl = get_acl(inode, ACL_TYPE_ACCESS); | |
789b663a TM |
603 | if (IS_ERR_OR_NULL(acl)) { |
604 | if (acl == ERR_PTR(-EOPNOTSUPP)) | |
605 | return 0; | |
5bf3258f | 606 | return PTR_ERR(acl); |
789b663a | 607 | } |
5bf3258f | 608 | |
37bc1539 | 609 | ret = __posix_acl_chmod(&acl, GFP_KERNEL, mode); |
5bf3258f CH |
610 | if (ret) |
611 | return ret; | |
549c7297 | 612 | ret = inode->i_op->set_acl(mnt_userns, inode, acl, ACL_TYPE_ACCESS); |
5bf3258f CH |
613 | posix_acl_release(acl); |
614 | return ret; | |
615 | } | |
bc26ab5f | 616 | EXPORT_SYMBOL(posix_acl_chmod); |
5c8ebd57 | 617 | |
37bc1539 CH |
618 | int |
619 | posix_acl_create(struct inode *dir, umode_t *mode, | |
620 | struct posix_acl **default_acl, struct posix_acl **acl) | |
621 | { | |
622 | struct posix_acl *p; | |
c0c3a718 | 623 | struct posix_acl *clone; |
37bc1539 CH |
624 | int ret; |
625 | ||
c0c3a718 DC |
626 | *acl = NULL; |
627 | *default_acl = NULL; | |
628 | ||
37bc1539 | 629 | if (S_ISLNK(*mode) || !IS_POSIXACL(dir)) |
c0c3a718 | 630 | return 0; |
37bc1539 CH |
631 | |
632 | p = get_acl(dir, ACL_TYPE_DEFAULT); | |
c0c3a718 DC |
633 | if (!p || p == ERR_PTR(-EOPNOTSUPP)) { |
634 | *mode &= ~current_umask(); | |
635 | return 0; | |
37bc1539 | 636 | } |
c0c3a718 DC |
637 | if (IS_ERR(p)) |
638 | return PTR_ERR(p); | |
37bc1539 | 639 | |
beaf226b | 640 | ret = -ENOMEM; |
c0c3a718 DC |
641 | clone = posix_acl_clone(p, GFP_NOFS); |
642 | if (!clone) | |
beaf226b | 643 | goto err_release; |
37bc1539 | 644 | |
c0c3a718 | 645 | ret = posix_acl_create_masq(clone, mode); |
fed0b588 | 646 | if (ret < 0) |
beaf226b | 647 | goto err_release_clone; |
37bc1539 | 648 | |
c0c3a718 DC |
649 | if (ret == 0) |
650 | posix_acl_release(clone); | |
651 | else | |
652 | *acl = clone; | |
37bc1539 | 653 | |
c0c3a718 | 654 | if (!S_ISDIR(*mode)) |
37bc1539 | 655 | posix_acl_release(p); |
c0c3a718 | 656 | else |
37bc1539 | 657 | *default_acl = p; |
37bc1539 | 658 | |
37bc1539 | 659 | return 0; |
fed0b588 | 660 | |
beaf226b | 661 | err_release_clone: |
c0c3a718 | 662 | posix_acl_release(clone); |
beaf226b | 663 | err_release: |
fed0b588 | 664 | posix_acl_release(p); |
beaf226b | 665 | return ret; |
37bc1539 CH |
666 | } |
667 | EXPORT_SYMBOL_GPL(posix_acl_create); | |
668 | ||
07393101 JK |
669 | /** |
670 | * posix_acl_update_mode - update mode in set_acl | |
e65ce2a5 CB |
671 | * @mnt_userns: user namespace of the mount @inode was found from |
672 | * @inode: target inode | |
673 | * @mode_p: mode (pointer) for update | |
674 | * @acl: acl pointer | |
07393101 JK |
675 | * |
676 | * Update the file mode when setting an ACL: compute the new file permission | |
677 | * bits based on the ACL. In addition, if the ACL is equivalent to the new | |
e39e773a | 678 | * file mode, set *@acl to NULL to indicate that no ACL should be set. |
07393101 | 679 | * |
e39e773a | 680 | * As with chmod, clear the setgid bit if the caller is not in the owning group |
07393101 JK |
681 | * or capable of CAP_FSETID (see inode_change_ok). |
682 | * | |
e65ce2a5 CB |
683 | * If the inode has been found through an idmapped mount the user namespace of |
684 | * the vfsmount must be passed through @mnt_userns. This function will then | |
685 | * take care to map the inode according to @mnt_userns before checking | |
686 | * permissions. On non-idmapped mounts or if permission checking is to be | |
687 | * performed on the raw inode simply passs init_user_ns. | |
688 | * | |
07393101 JK |
689 | * Called from set_acl inode operations. |
690 | */ | |
e65ce2a5 CB |
691 | int posix_acl_update_mode(struct user_namespace *mnt_userns, |
692 | struct inode *inode, umode_t *mode_p, | |
07393101 JK |
693 | struct posix_acl **acl) |
694 | { | |
695 | umode_t mode = inode->i_mode; | |
696 | int error; | |
697 | ||
698 | error = posix_acl_equiv_mode(*acl, &mode); | |
699 | if (error < 0) | |
700 | return error; | |
701 | if (error == 0) | |
702 | *acl = NULL; | |
e933c15f | 703 | if (!vfsgid_in_group_p(i_gid_into_vfsgid(mnt_userns, inode)) && |
e65ce2a5 | 704 | !capable_wrt_inode_uidgid(mnt_userns, inode, CAP_FSETID)) |
07393101 JK |
705 | mode &= ~S_ISGID; |
706 | *mode_p = mode; | |
707 | return 0; | |
708 | } | |
709 | EXPORT_SYMBOL(posix_acl_update_mode); | |
710 | ||
5c8ebd57 CH |
711 | /* |
712 | * Fix up the uids and gids in posix acl extended attributes in place. | |
713 | */ | |
985a6d0b | 714 | static int posix_acl_fix_xattr_common(const void *value, size_t size) |
0c5fd887 | 715 | { |
985a6d0b | 716 | const struct posix_acl_xattr_header *header = value; |
0c5fd887 CB |
717 | int count; |
718 | ||
719 | if (!header) | |
720 | return -EINVAL; | |
721 | if (size < sizeof(struct posix_acl_xattr_header)) | |
722 | return -EINVAL; | |
723 | if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION)) | |
985a6d0b | 724 | return -EOPNOTSUPP; |
0c5fd887 CB |
725 | |
726 | count = posix_acl_xattr_count(size); | |
727 | if (count < 0) | |
728 | return -EINVAL; | |
729 | if (count == 0) | |
985a6d0b | 730 | return 0; |
0c5fd887 CB |
731 | |
732 | return count; | |
733 | } | |
734 | ||
735 | void posix_acl_getxattr_idmapped_mnt(struct user_namespace *mnt_userns, | |
736 | const struct inode *inode, | |
737 | void *value, size_t size) | |
5c8ebd57 | 738 | { |
2211d5ba AG |
739 | struct posix_acl_xattr_header *header = value; |
740 | struct posix_acl_xattr_entry *entry = (void *)(header + 1), *end; | |
abfcf55d | 741 | struct user_namespace *fs_userns = i_user_ns(inode); |
5c8ebd57 | 742 | int count; |
0c5fd887 CB |
743 | vfsuid_t vfsuid; |
744 | vfsgid_t vfsgid; | |
5c8ebd57 CH |
745 | kuid_t uid; |
746 | kgid_t gid; | |
747 | ||
0c5fd887 | 748 | if (no_idmapping(mnt_userns, i_user_ns(inode))) |
5c8ebd57 | 749 | return; |
0c5fd887 CB |
750 | |
751 | count = posix_acl_fix_xattr_common(value, size); | |
985a6d0b | 752 | if (count <= 0) |
5c8ebd57 | 753 | return; |
0c5fd887 CB |
754 | |
755 | for (end = entry + count; entry != end; entry++) { | |
756 | switch (le16_to_cpu(entry->e_tag)) { | |
757 | case ACL_USER: | |
758 | uid = make_kuid(&init_user_ns, le32_to_cpu(entry->e_id)); | |
abfcf55d | 759 | vfsuid = make_vfsuid(mnt_userns, fs_userns, uid); |
0c5fd887 CB |
760 | entry->e_id = cpu_to_le32(from_kuid(&init_user_ns, |
761 | vfsuid_into_kuid(vfsuid))); | |
762 | break; | |
763 | case ACL_GROUP: | |
764 | gid = make_kgid(&init_user_ns, le32_to_cpu(entry->e_id)); | |
abfcf55d | 765 | vfsgid = make_vfsgid(mnt_userns, fs_userns, gid); |
0c5fd887 CB |
766 | entry->e_id = cpu_to_le32(from_kgid(&init_user_ns, |
767 | vfsgid_into_kgid(vfsgid))); | |
768 | break; | |
769 | default: | |
770 | break; | |
771 | } | |
772 | } | |
773 | } | |
774 | ||
0c5fd887 CB |
775 | static void posix_acl_fix_xattr_userns( |
776 | struct user_namespace *to, struct user_namespace *from, | |
777 | void *value, size_t size) | |
778 | { | |
779 | struct posix_acl_xattr_header *header = value; | |
780 | struct posix_acl_xattr_entry *entry = (void *)(header + 1), *end; | |
781 | int count; | |
782 | kuid_t uid; | |
783 | kgid_t gid; | |
784 | ||
785 | count = posix_acl_fix_xattr_common(value, size); | |
985a6d0b | 786 | if (count <= 0) |
5c8ebd57 CH |
787 | return; |
788 | ||
789 | for (end = entry + count; entry != end; entry++) { | |
790 | switch(le16_to_cpu(entry->e_tag)) { | |
791 | case ACL_USER: | |
792 | uid = make_kuid(from, le32_to_cpu(entry->e_id)); | |
793 | entry->e_id = cpu_to_le32(from_kuid(to, uid)); | |
794 | break; | |
795 | case ACL_GROUP: | |
796 | gid = make_kgid(from, le32_to_cpu(entry->e_id)); | |
797 | entry->e_id = cpu_to_le32(from_kgid(to, gid)); | |
798 | break; | |
799 | default: | |
800 | break; | |
801 | } | |
802 | } | |
803 | } | |
804 | ||
0c5fd887 | 805 | void posix_acl_fix_xattr_from_user(void *value, size_t size) |
5c8ebd57 CH |
806 | { |
807 | struct user_namespace *user_ns = current_user_ns(); | |
0c5fd887 | 808 | if (user_ns == &init_user_ns) |
5c8ebd57 | 809 | return; |
0c5fd887 | 810 | posix_acl_fix_xattr_userns(&init_user_ns, user_ns, value, size); |
5c8ebd57 CH |
811 | } |
812 | ||
0c5fd887 | 813 | void posix_acl_fix_xattr_to_user(void *value, size_t size) |
5c8ebd57 CH |
814 | { |
815 | struct user_namespace *user_ns = current_user_ns(); | |
0c5fd887 | 816 | if (user_ns == &init_user_ns) |
5c8ebd57 | 817 | return; |
0c5fd887 | 818 | posix_acl_fix_xattr_userns(user_ns, &init_user_ns, value, size); |
5c8ebd57 CH |
819 | } |
820 | ||
6b70fe06 CB |
821 | /** |
822 | * make_posix_acl - convert POSIX ACLs from uapi to VFS format using the | |
823 | * provided callbacks to map ACL_{GROUP,USER} entries into the | |
824 | * appropriate format | |
825 | * @mnt_userns: the mount's idmapping | |
826 | * @fs_userns: the filesystem's idmapping | |
827 | * @value: the uapi representation of POSIX ACLs | |
828 | * @size: the size of @void | |
829 | * @uid_cb: callback to use for mapping the uid stored in ACL_USER entries | |
830 | * @gid_cb: callback to use for mapping the gid stored in ACL_GROUP entries | |
831 | * | |
832 | * The make_posix_acl() helper is an abstraction to translate from uapi format | |
833 | * into the VFS format allowing the caller to specific callbacks to map | |
834 | * ACL_{GROUP,USER} entries into the expected format. This is used in | |
835 | * posix_acl_from_xattr() and vfs_set_acl_prepare() and avoids pointless code | |
836 | * duplication. | |
837 | * | |
838 | * Return: Allocated struct posix_acl on success, NULL for a valid header but | |
839 | * without actual POSIX ACL entries, or ERR_PTR() encoded error code. | |
5c8ebd57 | 840 | */ |
6b70fe06 CB |
841 | static struct posix_acl *make_posix_acl(struct user_namespace *mnt_userns, |
842 | struct user_namespace *fs_userns, const void *value, size_t size, | |
843 | kuid_t (*uid_cb)(struct user_namespace *, struct user_namespace *, | |
844 | const struct posix_acl_xattr_entry *), | |
845 | kgid_t (*gid_cb)(struct user_namespace *, struct user_namespace *, | |
846 | const struct posix_acl_xattr_entry *)) | |
5c8ebd57 | 847 | { |
2211d5ba AG |
848 | const struct posix_acl_xattr_header *header = value; |
849 | const struct posix_acl_xattr_entry *entry = (const void *)(header + 1), *end; | |
5c8ebd57 CH |
850 | int count; |
851 | struct posix_acl *acl; | |
852 | struct posix_acl_entry *acl_e; | |
853 | ||
985a6d0b | 854 | count = posix_acl_fix_xattr_common(value, size); |
5c8ebd57 | 855 | if (count < 0) |
985a6d0b | 856 | return ERR_PTR(count); |
5c8ebd57 CH |
857 | if (count == 0) |
858 | return NULL; | |
859 | ||
860 | acl = posix_acl_alloc(count, GFP_NOFS); | |
861 | if (!acl) | |
862 | return ERR_PTR(-ENOMEM); | |
863 | acl_e = acl->a_entries; | |
864 | ||
865 | for (end = entry + count; entry != end; acl_e++, entry++) { | |
866 | acl_e->e_tag = le16_to_cpu(entry->e_tag); | |
867 | acl_e->e_perm = le16_to_cpu(entry->e_perm); | |
868 | ||
869 | switch(acl_e->e_tag) { | |
870 | case ACL_USER_OBJ: | |
871 | case ACL_GROUP_OBJ: | |
872 | case ACL_MASK: | |
873 | case ACL_OTHER: | |
874 | break; | |
875 | ||
876 | case ACL_USER: | |
6b70fe06 | 877 | acl_e->e_uid = uid_cb(mnt_userns, fs_userns, entry); |
5c8ebd57 CH |
878 | if (!uid_valid(acl_e->e_uid)) |
879 | goto fail; | |
880 | break; | |
881 | case ACL_GROUP: | |
6b70fe06 | 882 | acl_e->e_gid = gid_cb(mnt_userns, fs_userns, entry); |
5c8ebd57 CH |
883 | if (!gid_valid(acl_e->e_gid)) |
884 | goto fail; | |
885 | break; | |
886 | ||
887 | default: | |
888 | goto fail; | |
889 | } | |
890 | } | |
891 | return acl; | |
892 | ||
893 | fail: | |
894 | posix_acl_release(acl); | |
895 | return ERR_PTR(-EINVAL); | |
896 | } | |
6b70fe06 CB |
897 | |
898 | /** | |
899 | * vfs_set_acl_prepare_kuid - map ACL_USER uid according to mount- and | |
900 | * filesystem idmapping | |
901 | * @mnt_userns: the mount's idmapping | |
902 | * @fs_userns: the filesystem's idmapping | |
903 | * @e: a ACL_USER entry in POSIX ACL uapi format | |
904 | * | |
905 | * The uid stored as ACL_USER entry in @e is a kuid_t stored as a raw {g,u}id | |
906 | * value. The vfs_set_acl_prepare_kuid() will recover the kuid_t through | |
907 | * KUIDT_INIT() and then map it according to the idmapped mount. The resulting | |
908 | * kuid_t is the value which the filesystem can map up into a raw backing store | |
909 | * id in the filesystem's idmapping. | |
910 | * | |
911 | * This is used in vfs_set_acl_prepare() to generate the proper VFS | |
912 | * representation of POSIX ACLs with ACL_USER entries during setxattr(). | |
913 | * | |
914 | * Return: A kuid in @fs_userns for the uid stored in @e. | |
915 | */ | |
916 | static inline kuid_t | |
917 | vfs_set_acl_prepare_kuid(struct user_namespace *mnt_userns, | |
918 | struct user_namespace *fs_userns, | |
919 | const struct posix_acl_xattr_entry *e) | |
920 | { | |
921 | kuid_t kuid = KUIDT_INIT(le32_to_cpu(e->e_id)); | |
922 | return from_vfsuid(mnt_userns, fs_userns, VFSUIDT_INIT(kuid)); | |
923 | } | |
924 | ||
925 | /** | |
926 | * vfs_set_acl_prepare_kgid - map ACL_GROUP gid according to mount- and | |
927 | * filesystem idmapping | |
928 | * @mnt_userns: the mount's idmapping | |
929 | * @fs_userns: the filesystem's idmapping | |
930 | * @e: a ACL_GROUP entry in POSIX ACL uapi format | |
931 | * | |
932 | * The gid stored as ACL_GROUP entry in @e is a kgid_t stored as a raw {g,u}id | |
933 | * value. The vfs_set_acl_prepare_kgid() will recover the kgid_t through | |
934 | * KGIDT_INIT() and then map it according to the idmapped mount. The resulting | |
935 | * kgid_t is the value which the filesystem can map up into a raw backing store | |
936 | * id in the filesystem's idmapping. | |
937 | * | |
938 | * This is used in vfs_set_acl_prepare() to generate the proper VFS | |
939 | * representation of POSIX ACLs with ACL_GROUP entries during setxattr(). | |
940 | * | |
941 | * Return: A kgid in @fs_userns for the gid stored in @e. | |
942 | */ | |
943 | static inline kgid_t | |
944 | vfs_set_acl_prepare_kgid(struct user_namespace *mnt_userns, | |
945 | struct user_namespace *fs_userns, | |
946 | const struct posix_acl_xattr_entry *e) | |
947 | { | |
948 | kgid_t kgid = KGIDT_INIT(le32_to_cpu(e->e_id)); | |
949 | return from_vfsgid(mnt_userns, fs_userns, VFSGIDT_INIT(kgid)); | |
950 | } | |
951 | ||
952 | /** | |
953 | * vfs_set_acl_prepare - convert POSIX ACLs from uapi to VFS format taking | |
954 | * mount and filesystem idmappings into account | |
955 | * @mnt_userns: the mount's idmapping | |
956 | * @fs_userns: the filesystem's idmapping | |
957 | * @value: the uapi representation of POSIX ACLs | |
958 | * @size: the size of @void | |
959 | * | |
960 | * When setting POSIX ACLs with ACL_{GROUP,USER} entries they need to be | |
961 | * mapped according to the relevant mount- and filesystem idmapping. It is | |
962 | * important that the ACL_{GROUP,USER} entries in struct posix_acl will be | |
963 | * mapped into k{g,u}id_t that are supposed to be mapped up in the filesystem | |
964 | * idmapping. This is crucial since the resulting struct posix_acl might be | |
965 | * cached filesystem wide. The vfs_set_acl_prepare() function will take care to | |
966 | * perform all necessary idmappings. | |
967 | * | |
968 | * Note, that since basically forever the {g,u}id values encoded as | |
969 | * ACL_{GROUP,USER} entries in the uapi POSIX ACLs passed via @value contain | |
970 | * values that have been mapped according to the caller's idmapping. In other | |
971 | * words, POSIX ACLs passed in uapi format as @value during setxattr() contain | |
972 | * {g,u}id values in their ACL_{GROUP,USER} entries that should actually have | |
973 | * been stored as k{g,u}id_t. | |
974 | * | |
975 | * This means, vfs_set_acl_prepare() needs to first recover the k{g,u}id_t by | |
976 | * calling K{G,U}IDT_INIT(). Afterwards they can be interpreted as vfs{g,u}id_t | |
977 | * through from_vfs{g,u}id() to account for any idmapped mounts. The | |
978 | * vfs_set_acl_prepare_k{g,u}id() helpers will take care to generate the | |
979 | * correct k{g,u}id_t. | |
980 | * | |
981 | * The filesystem will then receive the POSIX ACLs ready to be cached | |
982 | * filesystem wide and ready to be written to the backing store taking the | |
983 | * filesystem's idmapping into account. | |
984 | * | |
985 | * Return: Allocated struct posix_acl on success, NULL for a valid header but | |
986 | * without actual POSIX ACL entries, or ERR_PTR() encoded error code. | |
987 | */ | |
988 | struct posix_acl *vfs_set_acl_prepare(struct user_namespace *mnt_userns, | |
989 | struct user_namespace *fs_userns, | |
990 | const void *value, size_t size) | |
991 | { | |
992 | return make_posix_acl(mnt_userns, fs_userns, value, size, | |
993 | vfs_set_acl_prepare_kuid, | |
994 | vfs_set_acl_prepare_kgid); | |
995 | } | |
996 | EXPORT_SYMBOL(vfs_set_acl_prepare); | |
997 | ||
998 | /** | |
999 | * posix_acl_from_xattr_kuid - map ACL_USER uid into filesystem idmapping | |
1000 | * @mnt_userns: unused | |
1001 | * @fs_userns: the filesystem's idmapping | |
1002 | * @e: a ACL_USER entry in POSIX ACL uapi format | |
1003 | * | |
1004 | * Map the uid stored as ACL_USER entry in @e into the filesystem's idmapping. | |
1005 | * This is used in posix_acl_from_xattr() to generate the proper VFS | |
1006 | * representation of POSIX ACLs with ACL_USER entries. | |
1007 | * | |
1008 | * Return: A kuid in @fs_userns for the uid stored in @e. | |
1009 | */ | |
1010 | static inline kuid_t | |
1011 | posix_acl_from_xattr_kuid(struct user_namespace *mnt_userns, | |
1012 | struct user_namespace *fs_userns, | |
1013 | const struct posix_acl_xattr_entry *e) | |
1014 | { | |
1015 | return make_kuid(fs_userns, le32_to_cpu(e->e_id)); | |
1016 | } | |
1017 | ||
1018 | /** | |
1019 | * posix_acl_from_xattr_kgid - map ACL_GROUP gid into filesystem idmapping | |
1020 | * @mnt_userns: unused | |
1021 | * @fs_userns: the filesystem's idmapping | |
1022 | * @e: a ACL_GROUP entry in POSIX ACL uapi format | |
1023 | * | |
1024 | * Map the gid stored as ACL_GROUP entry in @e into the filesystem's idmapping. | |
1025 | * This is used in posix_acl_from_xattr() to generate the proper VFS | |
1026 | * representation of POSIX ACLs with ACL_GROUP entries. | |
1027 | * | |
1028 | * Return: A kgid in @fs_userns for the gid stored in @e. | |
1029 | */ | |
1030 | static inline kgid_t | |
1031 | posix_acl_from_xattr_kgid(struct user_namespace *mnt_userns, | |
1032 | struct user_namespace *fs_userns, | |
1033 | const struct posix_acl_xattr_entry *e) | |
1034 | { | |
1035 | return make_kgid(fs_userns, le32_to_cpu(e->e_id)); | |
1036 | } | |
1037 | ||
1038 | /** | |
1039 | * posix_acl_from_xattr - convert POSIX ACLs from backing store to VFS format | |
1040 | * @fs_userns: the filesystem's idmapping | |
1041 | * @value: the uapi representation of POSIX ACLs | |
1042 | * @size: the size of @void | |
1043 | * | |
1044 | * Filesystems that store POSIX ACLs in the unaltered uapi format should use | |
1045 | * posix_acl_from_xattr() when reading them from the backing store and | |
1046 | * converting them into the struct posix_acl VFS format. The helper is | |
1047 | * specifically intended to be called from the ->get_acl() inode operation. | |
1048 | * | |
1049 | * The posix_acl_from_xattr() function will map the raw {g,u}id values stored | |
1050 | * in ACL_{GROUP,USER} entries into the filesystem idmapping in @fs_userns. The | |
1051 | * posix_acl_from_xattr_k{g,u}id() helpers will take care to generate the | |
1052 | * correct k{g,u}id_t. The returned struct posix_acl can be cached. | |
1053 | * | |
1054 | * Note that posix_acl_from_xattr() does not take idmapped mounts into account. | |
1055 | * If it did it calling is from the ->get_acl() inode operation would return | |
1056 | * POSIX ACLs mapped according to an idmapped mount which would mean that the | |
1057 | * value couldn't be cached for the filesystem. Idmapped mounts are taken into | |
1058 | * account on the fly during permission checking or right at the VFS - | |
1059 | * userspace boundary before reporting them to the user. | |
1060 | * | |
1061 | * Return: Allocated struct posix_acl on success, NULL for a valid header but | |
1062 | * without actual POSIX ACL entries, or ERR_PTR() encoded error code. | |
1063 | */ | |
1064 | struct posix_acl * | |
1065 | posix_acl_from_xattr(struct user_namespace *fs_userns, | |
1066 | const void *value, size_t size) | |
1067 | { | |
1068 | return make_posix_acl(&init_user_ns, fs_userns, value, size, | |
1069 | posix_acl_from_xattr_kuid, | |
1070 | posix_acl_from_xattr_kgid); | |
1071 | } | |
5c8ebd57 CH |
1072 | EXPORT_SYMBOL (posix_acl_from_xattr); |
1073 | ||
1074 | /* | |
1075 | * Convert from in-memory to extended attribute representation. | |
1076 | */ | |
1077 | int | |
1078 | posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl, | |
1079 | void *buffer, size_t size) | |
1080 | { | |
2211d5ba AG |
1081 | struct posix_acl_xattr_header *ext_acl = buffer; |
1082 | struct posix_acl_xattr_entry *ext_entry; | |
5c8ebd57 CH |
1083 | int real_size, n; |
1084 | ||
1085 | real_size = posix_acl_xattr_size(acl->a_count); | |
1086 | if (!buffer) | |
1087 | return real_size; | |
1088 | if (real_size > size) | |
1089 | return -ERANGE; | |
47ba9734 | 1090 | |
2211d5ba | 1091 | ext_entry = (void *)(ext_acl + 1); |
5c8ebd57 CH |
1092 | ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION); |
1093 | ||
1094 | for (n=0; n < acl->a_count; n++, ext_entry++) { | |
1095 | const struct posix_acl_entry *acl_e = &acl->a_entries[n]; | |
1096 | ext_entry->e_tag = cpu_to_le16(acl_e->e_tag); | |
1097 | ext_entry->e_perm = cpu_to_le16(acl_e->e_perm); | |
1098 | switch(acl_e->e_tag) { | |
1099 | case ACL_USER: | |
1100 | ext_entry->e_id = | |
1101 | cpu_to_le32(from_kuid(user_ns, acl_e->e_uid)); | |
1102 | break; | |
1103 | case ACL_GROUP: | |
1104 | ext_entry->e_id = | |
1105 | cpu_to_le32(from_kgid(user_ns, acl_e->e_gid)); | |
1106 | break; | |
1107 | default: | |
1108 | ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID); | |
1109 | break; | |
1110 | } | |
1111 | } | |
1112 | return real_size; | |
1113 | } | |
1114 | EXPORT_SYMBOL (posix_acl_to_xattr); | |
2aeccbe9 CH |
1115 | |
1116 | static int | |
d9a82a04 | 1117 | posix_acl_xattr_get(const struct xattr_handler *handler, |
b296821a AV |
1118 | struct dentry *unused, struct inode *inode, |
1119 | const char *name, void *value, size_t size) | |
2aeccbe9 CH |
1120 | { |
1121 | struct posix_acl *acl; | |
1122 | int error; | |
1123 | ||
b296821a | 1124 | if (!IS_POSIXACL(inode)) |
2aeccbe9 | 1125 | return -EOPNOTSUPP; |
b296821a | 1126 | if (S_ISLNK(inode->i_mode)) |
2aeccbe9 CH |
1127 | return -EOPNOTSUPP; |
1128 | ||
b296821a | 1129 | acl = get_acl(inode, handler->flags); |
2aeccbe9 CH |
1130 | if (IS_ERR(acl)) |
1131 | return PTR_ERR(acl); | |
1132 | if (acl == NULL) | |
1133 | return -ENODATA; | |
1134 | ||
1135 | error = posix_acl_to_xattr(&init_user_ns, acl, value, size); | |
1136 | posix_acl_release(acl); | |
1137 | ||
1138 | return error; | |
1139 | } | |
1140 | ||
485e71e8 | 1141 | int |
e65ce2a5 CB |
1142 | set_posix_acl(struct user_namespace *mnt_userns, struct inode *inode, |
1143 | int type, struct posix_acl *acl) | |
2aeccbe9 | 1144 | { |
2aeccbe9 CH |
1145 | if (!IS_POSIXACL(inode)) |
1146 | return -EOPNOTSUPP; | |
1147 | if (!inode->i_op->set_acl) | |
1148 | return -EOPNOTSUPP; | |
1149 | ||
485e71e8 AG |
1150 | if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode)) |
1151 | return acl ? -EACCES : 0; | |
e65ce2a5 | 1152 | if (!inode_owner_or_capable(mnt_userns, inode)) |
2aeccbe9 CH |
1153 | return -EPERM; |
1154 | ||
485e71e8 | 1155 | if (acl) { |
a867d734 | 1156 | int ret = posix_acl_valid(inode->i_sb->s_user_ns, acl); |
485e71e8 AG |
1157 | if (ret) |
1158 | return ret; | |
1159 | } | |
549c7297 | 1160 | return inode->i_op->set_acl(mnt_userns, inode, acl, type); |
485e71e8 AG |
1161 | } |
1162 | EXPORT_SYMBOL(set_posix_acl); | |
1163 | ||
1164 | static int | |
1165 | posix_acl_xattr_set(const struct xattr_handler *handler, | |
e65ce2a5 CB |
1166 | struct user_namespace *mnt_userns, |
1167 | struct dentry *unused, struct inode *inode, | |
1168 | const char *name, const void *value, size_t size, | |
1169 | int flags) | |
485e71e8 AG |
1170 | { |
1171 | struct posix_acl *acl = NULL; | |
1172 | int ret; | |
1173 | ||
2aeccbe9 | 1174 | if (value) { |
52edb408 CB |
1175 | /* |
1176 | * By the time we end up here the {g,u}ids stored in | |
1177 | * ACL_{GROUP,USER} have already been mapped according to the | |
1178 | * caller's idmapping. The vfs_set_acl_prepare() helper will | |
1179 | * recover them and take idmapped mounts into account. The | |
0978c7c4 | 1180 | * filesystem will receive the POSIX ACLs in the correct |
52edb408 CB |
1181 | * format ready to be cached or written to the backing store |
1182 | * taking the filesystem idmapping into account. | |
1183 | */ | |
1184 | acl = vfs_set_acl_prepare(mnt_userns, i_user_ns(inode), | |
1185 | value, size); | |
2aeccbe9 CH |
1186 | if (IS_ERR(acl)) |
1187 | return PTR_ERR(acl); | |
2aeccbe9 | 1188 | } |
e65ce2a5 | 1189 | ret = set_posix_acl(mnt_userns, inode, handler->flags, acl); |
2aeccbe9 CH |
1190 | posix_acl_release(acl); |
1191 | return ret; | |
1192 | } | |
1193 | ||
764a5c6b AG |
1194 | static bool |
1195 | posix_acl_xattr_list(struct dentry *dentry) | |
2aeccbe9 | 1196 | { |
764a5c6b | 1197 | return IS_POSIXACL(d_backing_inode(dentry)); |
2aeccbe9 CH |
1198 | } |
1199 | ||
1200 | const struct xattr_handler posix_acl_access_xattr_handler = { | |
98e9cb57 | 1201 | .name = XATTR_NAME_POSIX_ACL_ACCESS, |
2aeccbe9 CH |
1202 | .flags = ACL_TYPE_ACCESS, |
1203 | .list = posix_acl_xattr_list, | |
1204 | .get = posix_acl_xattr_get, | |
1205 | .set = posix_acl_xattr_set, | |
1206 | }; | |
1207 | EXPORT_SYMBOL_GPL(posix_acl_access_xattr_handler); | |
1208 | ||
1209 | const struct xattr_handler posix_acl_default_xattr_handler = { | |
98e9cb57 | 1210 | .name = XATTR_NAME_POSIX_ACL_DEFAULT, |
2aeccbe9 CH |
1211 | .flags = ACL_TYPE_DEFAULT, |
1212 | .list = posix_acl_xattr_list, | |
1213 | .get = posix_acl_xattr_get, | |
1214 | .set = posix_acl_xattr_set, | |
1215 | }; | |
1216 | EXPORT_SYMBOL_GPL(posix_acl_default_xattr_handler); | |
feda821e | 1217 | |
549c7297 CB |
1218 | int simple_set_acl(struct user_namespace *mnt_userns, struct inode *inode, |
1219 | struct posix_acl *acl, int type) | |
feda821e CH |
1220 | { |
1221 | int error; | |
1222 | ||
1223 | if (type == ACL_TYPE_ACCESS) { | |
549c7297 | 1224 | error = posix_acl_update_mode(mnt_userns, inode, |
497de07d GZ |
1225 | &inode->i_mode, &acl); |
1226 | if (error) | |
1227 | return error; | |
feda821e CH |
1228 | } |
1229 | ||
078cd827 | 1230 | inode->i_ctime = current_time(inode); |
36f05cab JL |
1231 | if (IS_I_VERSION(inode)) |
1232 | inode_inc_iversion(inode); | |
feda821e CH |
1233 | set_cached_acl(inode, type, acl); |
1234 | return 0; | |
1235 | } | |
1236 | ||
1237 | int simple_acl_create(struct inode *dir, struct inode *inode) | |
1238 | { | |
1239 | struct posix_acl *default_acl, *acl; | |
1240 | int error; | |
1241 | ||
1242 | error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl); | |
1243 | if (error) | |
1244 | return error; | |
1245 | ||
1246 | set_cached_acl(inode, ACL_TYPE_DEFAULT, default_acl); | |
1247 | set_cached_acl(inode, ACL_TYPE_ACCESS, acl); | |
1248 | ||
1249 | if (default_acl) | |
1250 | posix_acl_release(default_acl); | |
1251 | if (acl) | |
1252 | posix_acl_release(acl); | |
1253 | return 0; | |
1254 | } |