Commit | Line | Data |
---|---|---|
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> |
e4cc9163 CB |
28 | #include <linux/security.h> |
29 | #include <linux/evm.h> | |
30 | #include <linux/fsnotify.h> | |
31 | ||
32 | #include "internal.h" | |
1da177e4 | 33 | |
04c57f45 | 34 | static struct posix_acl **acl_by_type(struct inode *inode, int type) |
0afaa120 AM |
35 | { |
36 | switch (type) { | |
37 | case ACL_TYPE_ACCESS: | |
38 | return &inode->i_acl; | |
39 | case ACL_TYPE_DEFAULT: | |
40 | return &inode->i_default_acl; | |
41 | default: | |
42 | BUG(); | |
43 | } | |
44 | } | |
0afaa120 AM |
45 | |
46 | struct posix_acl *get_cached_acl(struct inode *inode, int type) | |
47 | { | |
48 | struct posix_acl **p = acl_by_type(inode, type); | |
b8a7a3a6 AG |
49 | struct posix_acl *acl; |
50 | ||
51 | for (;;) { | |
52 | rcu_read_lock(); | |
53 | acl = rcu_dereference(*p); | |
54 | if (!acl || is_uncached_acl(acl) || | |
66717260 | 55 | refcount_inc_not_zero(&acl->a_refcount)) |
b8a7a3a6 AG |
56 | break; |
57 | rcu_read_unlock(); | |
58 | cpu_relax(); | |
0afaa120 | 59 | } |
b8a7a3a6 | 60 | rcu_read_unlock(); |
0afaa120 AM |
61 | return acl; |
62 | } | |
63 | EXPORT_SYMBOL(get_cached_acl); | |
64 | ||
65 | struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type) | |
66 | { | |
332f606b MS |
67 | struct posix_acl *acl = rcu_dereference(*acl_by_type(inode, type)); |
68 | ||
69 | if (acl == ACL_DONT_CACHE) { | |
70 | struct posix_acl *ret; | |
71 | ||
cac2f8b8 | 72 | ret = inode->i_op->get_inode_acl(inode, type, LOOKUP_RCU); |
332f606b MS |
73 | if (!IS_ERR(ret)) |
74 | acl = ret; | |
75 | } | |
76 | ||
77 | return acl; | |
0afaa120 AM |
78 | } |
79 | EXPORT_SYMBOL(get_cached_acl_rcu); | |
80 | ||
81 | void set_cached_acl(struct inode *inode, int type, struct posix_acl *acl) | |
82 | { | |
83 | struct posix_acl **p = acl_by_type(inode, type); | |
84 | struct posix_acl *old; | |
b8a7a3a6 AG |
85 | |
86 | old = xchg(p, posix_acl_dup(acl)); | |
87 | if (!is_uncached_acl(old)) | |
0afaa120 AM |
88 | posix_acl_release(old); |
89 | } | |
90 | EXPORT_SYMBOL(set_cached_acl); | |
91 | ||
b8a7a3a6 | 92 | static void __forget_cached_acl(struct posix_acl **p) |
0afaa120 | 93 | { |
0afaa120 | 94 | struct posix_acl *old; |
b8a7a3a6 AG |
95 | |
96 | old = xchg(p, ACL_NOT_CACHED); | |
97 | if (!is_uncached_acl(old)) | |
0afaa120 AM |
98 | posix_acl_release(old); |
99 | } | |
b8a7a3a6 AG |
100 | |
101 | void forget_cached_acl(struct inode *inode, int type) | |
102 | { | |
103 | __forget_cached_acl(acl_by_type(inode, type)); | |
104 | } | |
0afaa120 AM |
105 | EXPORT_SYMBOL(forget_cached_acl); |
106 | ||
107 | void forget_all_cached_acls(struct inode *inode) | |
108 | { | |
b8a7a3a6 AG |
109 | __forget_cached_acl(&inode->i_acl); |
110 | __forget_cached_acl(&inode->i_default_acl); | |
0afaa120 AM |
111 | } |
112 | EXPORT_SYMBOL(forget_all_cached_acls); | |
1da177e4 | 113 | |
4f353ba4 CB |
114 | static struct posix_acl *__get_acl(struct user_namespace *mnt_userns, |
115 | struct dentry *dentry, struct inode *inode, | |
116 | int type) | |
2982baa2 | 117 | { |
b8a7a3a6 AG |
118 | void *sentinel; |
119 | struct posix_acl **p; | |
2982baa2 CH |
120 | struct posix_acl *acl; |
121 | ||
b8a7a3a6 AG |
122 | /* |
123 | * The sentinel is used to detect when another operation like | |
cac2f8b8 | 124 | * set_cached_acl() or forget_cached_acl() races with get_inode_acl(). |
b8a7a3a6 AG |
125 | * It is guaranteed that is_uncached_acl(sentinel) is true. |
126 | */ | |
127 | ||
2982baa2 | 128 | acl = get_cached_acl(inode, type); |
b8a7a3a6 | 129 | if (!is_uncached_acl(acl)) |
2982baa2 CH |
130 | return acl; |
131 | ||
132 | if (!IS_POSIXACL(inode)) | |
133 | return NULL; | |
134 | ||
b8a7a3a6 AG |
135 | sentinel = uncached_acl_sentinel(current); |
136 | p = acl_by_type(inode, type); | |
137 | ||
138 | /* | |
139 | * If the ACL isn't being read yet, set our sentinel. Otherwise, the | |
140 | * current value of the ACL will not be ACL_NOT_CACHED and so our own | |
141 | * sentinel will not be set; another task will update the cache. We | |
142 | * could wait for that other task to complete its job, but it's easier | |
cac2f8b8 CB |
143 | * to just call ->get_inode_acl to fetch the ACL ourself. (This is |
144 | * going to be an unlikely race.) | |
b8a7a3a6 | 145 | */ |
d1cef29a | 146 | cmpxchg(p, ACL_NOT_CACHED, sentinel); |
b8a7a3a6 | 147 | |
2982baa2 | 148 | /* |
4f353ba4 | 149 | * Normally, the ACL returned by ->get{_inode}_acl will be cached. |
b8a7a3a6 | 150 | * A filesystem can prevent that by calling |
4f353ba4 | 151 | * forget_cached_acl(inode, type) in ->get{_inode}_acl. |
2982baa2 | 152 | * |
4f353ba4 | 153 | * If the filesystem doesn't have a get{_inode}_ acl() function at all, |
cac2f8b8 | 154 | * we'll just create the negative cache entry. |
2982baa2 | 155 | */ |
4f353ba4 CB |
156 | if (dentry && inode->i_op->get_acl) { |
157 | acl = inode->i_op->get_acl(mnt_userns, dentry, type); | |
158 | } else if (inode->i_op->get_inode_acl) { | |
159 | acl = inode->i_op->get_inode_acl(inode, type, false); | |
160 | } else { | |
2982baa2 CH |
161 | set_cached_acl(inode, type, NULL); |
162 | return NULL; | |
163 | } | |
b8a7a3a6 AG |
164 | if (IS_ERR(acl)) { |
165 | /* | |
166 | * Remove our sentinel so that we don't block future attempts | |
167 | * to cache the ACL. | |
168 | */ | |
169 | cmpxchg(p, sentinel, ACL_NOT_CACHED); | |
170 | return acl; | |
171 | } | |
172 | ||
173 | /* | |
174 | * Cache the result, but only if our sentinel is still in place. | |
175 | */ | |
176 | posix_acl_dup(acl); | |
177 | if (unlikely(cmpxchg(p, sentinel, acl) != sentinel)) | |
178 | posix_acl_release(acl); | |
179 | return acl; | |
2982baa2 | 180 | } |
4f353ba4 CB |
181 | |
182 | struct posix_acl *get_inode_acl(struct inode *inode, int type) | |
183 | { | |
184 | return __get_acl(&init_user_ns, NULL, inode, type); | |
185 | } | |
cac2f8b8 | 186 | EXPORT_SYMBOL(get_inode_acl); |
2982baa2 | 187 | |
f61f6da0 CL |
188 | /* |
189 | * Init a fresh posix_acl | |
190 | */ | |
191 | void | |
192 | posix_acl_init(struct posix_acl *acl, int count) | |
193 | { | |
66717260 | 194 | refcount_set(&acl->a_refcount, 1); |
f61f6da0 CL |
195 | acl->a_count = count; |
196 | } | |
0afaa120 | 197 | EXPORT_SYMBOL(posix_acl_init); |
f61f6da0 | 198 | |
1da177e4 LT |
199 | /* |
200 | * Allocate a new ACL with the specified number of entries. | |
201 | */ | |
202 | struct posix_acl * | |
dd0fc66f | 203 | posix_acl_alloc(int count, gfp_t flags) |
1da177e4 LT |
204 | { |
205 | const size_t size = sizeof(struct posix_acl) + | |
206 | count * sizeof(struct posix_acl_entry); | |
207 | struct posix_acl *acl = kmalloc(size, flags); | |
f61f6da0 CL |
208 | if (acl) |
209 | posix_acl_init(acl, count); | |
1da177e4 LT |
210 | return acl; |
211 | } | |
0afaa120 | 212 | EXPORT_SYMBOL(posix_acl_alloc); |
1da177e4 LT |
213 | |
214 | /* | |
215 | * Clone an ACL. | |
216 | */ | |
8043bffd | 217 | struct posix_acl * |
dd0fc66f | 218 | posix_acl_clone(const struct posix_acl *acl, gfp_t flags) |
1da177e4 LT |
219 | { |
220 | struct posix_acl *clone = NULL; | |
221 | ||
222 | if (acl) { | |
223 | int size = sizeof(struct posix_acl) + acl->a_count * | |
224 | sizeof(struct posix_acl_entry); | |
52978be6 AD |
225 | clone = kmemdup(acl, size, flags); |
226 | if (clone) | |
66717260 | 227 | refcount_set(&clone->a_refcount, 1); |
1da177e4 LT |
228 | } |
229 | return clone; | |
230 | } | |
8043bffd | 231 | EXPORT_SYMBOL_GPL(posix_acl_clone); |
1da177e4 LT |
232 | |
233 | /* | |
234 | * Check if an acl is valid. Returns 0 if it is, or -E... otherwise. | |
235 | */ | |
236 | int | |
0d4d717f | 237 | posix_acl_valid(struct user_namespace *user_ns, const struct posix_acl *acl) |
1da177e4 LT |
238 | { |
239 | const struct posix_acl_entry *pa, *pe; | |
240 | int state = ACL_USER_OBJ; | |
1da177e4 LT |
241 | int needs_mask = 0; |
242 | ||
243 | FOREACH_ACL_ENTRY(pa, acl, pe) { | |
244 | if (pa->e_perm & ~(ACL_READ|ACL_WRITE|ACL_EXECUTE)) | |
245 | return -EINVAL; | |
246 | switch (pa->e_tag) { | |
247 | case ACL_USER_OBJ: | |
248 | if (state == ACL_USER_OBJ) { | |
1da177e4 LT |
249 | state = ACL_USER; |
250 | break; | |
251 | } | |
252 | return -EINVAL; | |
253 | ||
254 | case ACL_USER: | |
255 | if (state != ACL_USER) | |
256 | return -EINVAL; | |
0d4d717f | 257 | if (!kuid_has_mapping(user_ns, pa->e_uid)) |
1da177e4 | 258 | return -EINVAL; |
1da177e4 LT |
259 | needs_mask = 1; |
260 | break; | |
261 | ||
262 | case ACL_GROUP_OBJ: | |
263 | if (state == ACL_USER) { | |
1da177e4 LT |
264 | state = ACL_GROUP; |
265 | break; | |
266 | } | |
267 | return -EINVAL; | |
268 | ||
269 | case ACL_GROUP: | |
270 | if (state != ACL_GROUP) | |
271 | return -EINVAL; | |
0d4d717f | 272 | if (!kgid_has_mapping(user_ns, pa->e_gid)) |
2f6f0654 | 273 | return -EINVAL; |
1da177e4 LT |
274 | needs_mask = 1; |
275 | break; | |
276 | ||
277 | case ACL_MASK: | |
278 | if (state != ACL_GROUP) | |
279 | return -EINVAL; | |
280 | state = ACL_OTHER; | |
281 | break; | |
282 | ||
283 | case ACL_OTHER: | |
284 | if (state == ACL_OTHER || | |
285 | (state == ACL_GROUP && !needs_mask)) { | |
286 | state = 0; | |
287 | break; | |
288 | } | |
289 | return -EINVAL; | |
290 | ||
291 | default: | |
292 | return -EINVAL; | |
293 | } | |
294 | } | |
295 | if (state == 0) | |
296 | return 0; | |
297 | return -EINVAL; | |
298 | } | |
0afaa120 | 299 | EXPORT_SYMBOL(posix_acl_valid); |
1da177e4 LT |
300 | |
301 | /* | |
302 | * Returns 0 if the acl can be exactly represented in the traditional | |
303 | * file mode permission bits, or else 1. Returns -E... on error. | |
304 | */ | |
305 | int | |
d6952123 | 306 | posix_acl_equiv_mode(const struct posix_acl *acl, umode_t *mode_p) |
1da177e4 LT |
307 | { |
308 | const struct posix_acl_entry *pa, *pe; | |
d6952123 | 309 | umode_t mode = 0; |
1da177e4 LT |
310 | int not_equiv = 0; |
311 | ||
50c6e282 CH |
312 | /* |
313 | * A null ACL can always be presented as mode bits. | |
314 | */ | |
315 | if (!acl) | |
316 | return 0; | |
317 | ||
1da177e4 LT |
318 | FOREACH_ACL_ENTRY(pa, acl, pe) { |
319 | switch (pa->e_tag) { | |
320 | case ACL_USER_OBJ: | |
321 | mode |= (pa->e_perm & S_IRWXO) << 6; | |
322 | break; | |
323 | case ACL_GROUP_OBJ: | |
324 | mode |= (pa->e_perm & S_IRWXO) << 3; | |
325 | break; | |
326 | case ACL_OTHER: | |
327 | mode |= pa->e_perm & S_IRWXO; | |
328 | break; | |
329 | case ACL_MASK: | |
330 | mode = (mode & ~S_IRWXG) | | |
331 | ((pa->e_perm & S_IRWXO) << 3); | |
332 | not_equiv = 1; | |
333 | break; | |
334 | case ACL_USER: | |
335 | case ACL_GROUP: | |
336 | not_equiv = 1; | |
337 | break; | |
338 | default: | |
339 | return -EINVAL; | |
340 | } | |
341 | } | |
342 | if (mode_p) | |
343 | *mode_p = (*mode_p & ~S_IRWXUGO) | mode; | |
344 | return not_equiv; | |
345 | } | |
0afaa120 | 346 | EXPORT_SYMBOL(posix_acl_equiv_mode); |
1da177e4 LT |
347 | |
348 | /* | |
349 | * Create an ACL representing the file mode permission bits of an inode. | |
350 | */ | |
351 | struct posix_acl * | |
3a5fba19 | 352 | posix_acl_from_mode(umode_t mode, gfp_t flags) |
1da177e4 LT |
353 | { |
354 | struct posix_acl *acl = posix_acl_alloc(3, flags); | |
355 | if (!acl) | |
356 | return ERR_PTR(-ENOMEM); | |
357 | ||
358 | acl->a_entries[0].e_tag = ACL_USER_OBJ; | |
1da177e4 LT |
359 | acl->a_entries[0].e_perm = (mode & S_IRWXU) >> 6; |
360 | ||
361 | acl->a_entries[1].e_tag = ACL_GROUP_OBJ; | |
1da177e4 LT |
362 | acl->a_entries[1].e_perm = (mode & S_IRWXG) >> 3; |
363 | ||
364 | acl->a_entries[2].e_tag = ACL_OTHER; | |
1da177e4 LT |
365 | acl->a_entries[2].e_perm = (mode & S_IRWXO); |
366 | return acl; | |
367 | } | |
0afaa120 | 368 | EXPORT_SYMBOL(posix_acl_from_mode); |
1da177e4 LT |
369 | |
370 | /* | |
371 | * Return 0 if current is granted want access to the inode | |
372 | * by the acl. Returns -E... otherwise. | |
373 | */ | |
374 | int | |
47291baa CB |
375 | posix_acl_permission(struct user_namespace *mnt_userns, struct inode *inode, |
376 | const struct posix_acl *acl, int want) | |
1da177e4 LT |
377 | { |
378 | const struct posix_acl_entry *pa, *pe, *mask_obj; | |
abfcf55d | 379 | struct user_namespace *fs_userns = i_user_ns(inode); |
1da177e4 | 380 | int found = 0; |
e933c15f CB |
381 | vfsuid_t vfsuid; |
382 | vfsgid_t vfsgid; | |
1da177e4 | 383 | |
63d72b93 | 384 | want &= MAY_READ | MAY_WRITE | MAY_EXEC; |
d124b60a | 385 | |
1da177e4 LT |
386 | FOREACH_ACL_ENTRY(pa, acl, pe) { |
387 | switch(pa->e_tag) { | |
388 | case ACL_USER_OBJ: | |
389 | /* (May have been checked already) */ | |
e933c15f CB |
390 | vfsuid = i_uid_into_vfsuid(mnt_userns, inode); |
391 | if (vfsuid_eq_kuid(vfsuid, current_fsuid())) | |
1da177e4 LT |
392 | goto check_perm; |
393 | break; | |
394 | case ACL_USER: | |
abfcf55d | 395 | vfsuid = make_vfsuid(mnt_userns, fs_userns, |
bd303368 | 396 | pa->e_uid); |
e933c15f | 397 | if (vfsuid_eq_kuid(vfsuid, current_fsuid())) |
1da177e4 LT |
398 | goto mask; |
399 | break; | |
400 | case ACL_GROUP_OBJ: | |
e933c15f CB |
401 | vfsgid = i_gid_into_vfsgid(mnt_userns, inode); |
402 | if (vfsgid_in_group_p(vfsgid)) { | |
1da177e4 LT |
403 | found = 1; |
404 | if ((pa->e_perm & want) == want) | |
405 | goto mask; | |
406 | } | |
407 | break; | |
408 | case ACL_GROUP: | |
abfcf55d | 409 | vfsgid = make_vfsgid(mnt_userns, fs_userns, |
bd303368 | 410 | pa->e_gid); |
e933c15f | 411 | if (vfsgid_in_group_p(vfsgid)) { |
1da177e4 LT |
412 | found = 1; |
413 | if ((pa->e_perm & want) == want) | |
414 | goto mask; | |
415 | } | |
416 | break; | |
417 | case ACL_MASK: | |
418 | break; | |
419 | case ACL_OTHER: | |
420 | if (found) | |
421 | return -EACCES; | |
422 | else | |
423 | goto check_perm; | |
424 | default: | |
425 | return -EIO; | |
426 | } | |
427 | } | |
428 | return -EIO; | |
429 | ||
430 | mask: | |
431 | for (mask_obj = pa+1; mask_obj != pe; mask_obj++) { | |
432 | if (mask_obj->e_tag == ACL_MASK) { | |
433 | if ((pa->e_perm & mask_obj->e_perm & want) == want) | |
434 | return 0; | |
435 | return -EACCES; | |
436 | } | |
437 | } | |
438 | ||
439 | check_perm: | |
440 | if ((pa->e_perm & want) == want) | |
441 | return 0; | |
442 | return -EACCES; | |
443 | } | |
444 | ||
445 | /* | |
446 | * Modify acl when creating a new inode. The caller must ensure the acl is | |
447 | * only referenced once. | |
448 | * | |
449 | * mode_p initially must contain the mode parameter to the open() / creat() | |
450 | * system calls. All permissions that are not granted by the acl are removed. | |
451 | * The permissions in the acl are changed to reflect the mode_p parameter. | |
452 | */ | |
d3fb6120 | 453 | static int posix_acl_create_masq(struct posix_acl *acl, umode_t *mode_p) |
1da177e4 LT |
454 | { |
455 | struct posix_acl_entry *pa, *pe; | |
456 | struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL; | |
d3fb6120 | 457 | umode_t mode = *mode_p; |
1da177e4 LT |
458 | int not_equiv = 0; |
459 | ||
460 | /* assert(atomic_read(acl->a_refcount) == 1); */ | |
461 | ||
462 | FOREACH_ACL_ENTRY(pa, acl, pe) { | |
463 | switch(pa->e_tag) { | |
464 | case ACL_USER_OBJ: | |
465 | pa->e_perm &= (mode >> 6) | ~S_IRWXO; | |
466 | mode &= (pa->e_perm << 6) | ~S_IRWXU; | |
467 | break; | |
468 | ||
469 | case ACL_USER: | |
470 | case ACL_GROUP: | |
471 | not_equiv = 1; | |
472 | break; | |
473 | ||
474 | case ACL_GROUP_OBJ: | |
475 | group_obj = pa; | |
476 | break; | |
477 | ||
478 | case ACL_OTHER: | |
479 | pa->e_perm &= mode | ~S_IRWXO; | |
480 | mode &= pa->e_perm | ~S_IRWXO; | |
481 | break; | |
482 | ||
483 | case ACL_MASK: | |
484 | mask_obj = pa; | |
485 | not_equiv = 1; | |
486 | break; | |
487 | ||
488 | default: | |
489 | return -EIO; | |
490 | } | |
491 | } | |
492 | ||
493 | if (mask_obj) { | |
494 | mask_obj->e_perm &= (mode >> 3) | ~S_IRWXO; | |
495 | mode &= (mask_obj->e_perm << 3) | ~S_IRWXG; | |
496 | } else { | |
497 | if (!group_obj) | |
498 | return -EIO; | |
499 | group_obj->e_perm &= (mode >> 3) | ~S_IRWXO; | |
500 | mode &= (group_obj->e_perm << 3) | ~S_IRWXG; | |
501 | } | |
502 | ||
503 | *mode_p = (*mode_p & ~S_IRWXUGO) | mode; | |
504 | return not_equiv; | |
505 | } | |
506 | ||
507 | /* | |
508 | * Modify the ACL for the chmod syscall. | |
509 | */ | |
5bf3258f | 510 | static int __posix_acl_chmod_masq(struct posix_acl *acl, umode_t mode) |
1da177e4 LT |
511 | { |
512 | struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL; | |
513 | struct posix_acl_entry *pa, *pe; | |
514 | ||
515 | /* assert(atomic_read(acl->a_refcount) == 1); */ | |
516 | ||
517 | FOREACH_ACL_ENTRY(pa, acl, pe) { | |
518 | switch(pa->e_tag) { | |
519 | case ACL_USER_OBJ: | |
520 | pa->e_perm = (mode & S_IRWXU) >> 6; | |
521 | break; | |
522 | ||
523 | case ACL_USER: | |
524 | case ACL_GROUP: | |
525 | break; | |
526 | ||
527 | case ACL_GROUP_OBJ: | |
528 | group_obj = pa; | |
529 | break; | |
530 | ||
531 | case ACL_MASK: | |
532 | mask_obj = pa; | |
533 | break; | |
534 | ||
535 | case ACL_OTHER: | |
536 | pa->e_perm = (mode & S_IRWXO); | |
537 | break; | |
538 | ||
539 | default: | |
540 | return -EIO; | |
541 | } | |
542 | } | |
543 | ||
544 | if (mask_obj) { | |
545 | mask_obj->e_perm = (mode & S_IRWXG) >> 3; | |
546 | } else { | |
547 | if (!group_obj) | |
548 | return -EIO; | |
549 | group_obj->e_perm = (mode & S_IRWXG) >> 3; | |
550 | } | |
551 | ||
552 | return 0; | |
553 | } | |
bc26ab5f | 554 | |
826cae2f | 555 | int |
37bc1539 | 556 | __posix_acl_create(struct posix_acl **acl, gfp_t gfp, umode_t *mode_p) |
826cae2f AV |
557 | { |
558 | struct posix_acl *clone = posix_acl_clone(*acl, gfp); | |
559 | int err = -ENOMEM; | |
560 | if (clone) { | |
561 | err = posix_acl_create_masq(clone, mode_p); | |
562 | if (err < 0) { | |
563 | posix_acl_release(clone); | |
564 | clone = NULL; | |
565 | } | |
566 | } | |
567 | posix_acl_release(*acl); | |
568 | *acl = clone; | |
569 | return err; | |
570 | } | |
37bc1539 | 571 | EXPORT_SYMBOL(__posix_acl_create); |
826cae2f | 572 | |
bc26ab5f | 573 | int |
5bf3258f | 574 | __posix_acl_chmod(struct posix_acl **acl, gfp_t gfp, umode_t mode) |
bc26ab5f AV |
575 | { |
576 | struct posix_acl *clone = posix_acl_clone(*acl, gfp); | |
577 | int err = -ENOMEM; | |
578 | if (clone) { | |
5bf3258f | 579 | err = __posix_acl_chmod_masq(clone, mode); |
bc26ab5f AV |
580 | if (err) { |
581 | posix_acl_release(clone); | |
582 | clone = NULL; | |
583 | } | |
584 | } | |
585 | posix_acl_release(*acl); | |
586 | *acl = clone; | |
587 | return err; | |
588 | } | |
5bf3258f CH |
589 | EXPORT_SYMBOL(__posix_acl_chmod); |
590 | ||
e65ce2a5 CB |
591 | /** |
592 | * posix_acl_chmod - chmod a posix acl | |
593 | * | |
594 | * @mnt_userns: user namespace of the mount @inode was found from | |
138060ba | 595 | * @dentry: dentry to check permissions on |
e65ce2a5 CB |
596 | * @mode: the new mode of @inode |
597 | * | |
138060ba | 598 | * If the dentry has been found through an idmapped mount the user namespace of |
e65ce2a5 CB |
599 | * the vfsmount must be passed through @mnt_userns. This function will then |
600 | * take care to map the inode according to @mnt_userns before checking | |
601 | * permissions. On non-idmapped mounts or if permission checking is to be | |
602 | * performed on the raw inode simply passs init_user_ns. | |
603 | */ | |
5bf3258f | 604 | int |
138060ba | 605 | posix_acl_chmod(struct user_namespace *mnt_userns, struct dentry *dentry, |
e65ce2a5 | 606 | umode_t mode) |
5bf3258f | 607 | { |
138060ba | 608 | struct inode *inode = d_inode(dentry); |
5bf3258f CH |
609 | struct posix_acl *acl; |
610 | int ret = 0; | |
611 | ||
612 | if (!IS_POSIXACL(inode)) | |
613 | return 0; | |
614 | if (!inode->i_op->set_acl) | |
615 | return -EOPNOTSUPP; | |
616 | ||
cac2f8b8 | 617 | acl = get_inode_acl(inode, ACL_TYPE_ACCESS); |
789b663a TM |
618 | if (IS_ERR_OR_NULL(acl)) { |
619 | if (acl == ERR_PTR(-EOPNOTSUPP)) | |
620 | return 0; | |
5bf3258f | 621 | return PTR_ERR(acl); |
789b663a | 622 | } |
5bf3258f | 623 | |
37bc1539 | 624 | ret = __posix_acl_chmod(&acl, GFP_KERNEL, mode); |
5bf3258f CH |
625 | if (ret) |
626 | return ret; | |
138060ba | 627 | ret = inode->i_op->set_acl(mnt_userns, dentry, acl, ACL_TYPE_ACCESS); |
5bf3258f CH |
628 | posix_acl_release(acl); |
629 | return ret; | |
630 | } | |
bc26ab5f | 631 | EXPORT_SYMBOL(posix_acl_chmod); |
5c8ebd57 | 632 | |
37bc1539 CH |
633 | int |
634 | posix_acl_create(struct inode *dir, umode_t *mode, | |
635 | struct posix_acl **default_acl, struct posix_acl **acl) | |
636 | { | |
637 | struct posix_acl *p; | |
c0c3a718 | 638 | struct posix_acl *clone; |
37bc1539 CH |
639 | int ret; |
640 | ||
c0c3a718 DC |
641 | *acl = NULL; |
642 | *default_acl = NULL; | |
643 | ||
37bc1539 | 644 | if (S_ISLNK(*mode) || !IS_POSIXACL(dir)) |
c0c3a718 | 645 | return 0; |
37bc1539 | 646 | |
cac2f8b8 | 647 | p = get_inode_acl(dir, ACL_TYPE_DEFAULT); |
c0c3a718 DC |
648 | if (!p || p == ERR_PTR(-EOPNOTSUPP)) { |
649 | *mode &= ~current_umask(); | |
650 | return 0; | |
37bc1539 | 651 | } |
c0c3a718 DC |
652 | if (IS_ERR(p)) |
653 | return PTR_ERR(p); | |
37bc1539 | 654 | |
beaf226b | 655 | ret = -ENOMEM; |
c0c3a718 DC |
656 | clone = posix_acl_clone(p, GFP_NOFS); |
657 | if (!clone) | |
beaf226b | 658 | goto err_release; |
37bc1539 | 659 | |
c0c3a718 | 660 | ret = posix_acl_create_masq(clone, mode); |
fed0b588 | 661 | if (ret < 0) |
beaf226b | 662 | goto err_release_clone; |
37bc1539 | 663 | |
c0c3a718 DC |
664 | if (ret == 0) |
665 | posix_acl_release(clone); | |
666 | else | |
667 | *acl = clone; | |
37bc1539 | 668 | |
c0c3a718 | 669 | if (!S_ISDIR(*mode)) |
37bc1539 | 670 | posix_acl_release(p); |
c0c3a718 | 671 | else |
37bc1539 | 672 | *default_acl = p; |
37bc1539 | 673 | |
37bc1539 | 674 | return 0; |
fed0b588 | 675 | |
beaf226b | 676 | err_release_clone: |
c0c3a718 | 677 | posix_acl_release(clone); |
beaf226b | 678 | err_release: |
fed0b588 | 679 | posix_acl_release(p); |
beaf226b | 680 | return ret; |
37bc1539 CH |
681 | } |
682 | EXPORT_SYMBOL_GPL(posix_acl_create); | |
683 | ||
07393101 JK |
684 | /** |
685 | * posix_acl_update_mode - update mode in set_acl | |
e65ce2a5 CB |
686 | * @mnt_userns: user namespace of the mount @inode was found from |
687 | * @inode: target inode | |
688 | * @mode_p: mode (pointer) for update | |
689 | * @acl: acl pointer | |
07393101 JK |
690 | * |
691 | * Update the file mode when setting an ACL: compute the new file permission | |
692 | * bits based on the ACL. In addition, if the ACL is equivalent to the new | |
e39e773a | 693 | * file mode, set *@acl to NULL to indicate that no ACL should be set. |
07393101 | 694 | * |
e39e773a | 695 | * As with chmod, clear the setgid bit if the caller is not in the owning group |
07393101 JK |
696 | * or capable of CAP_FSETID (see inode_change_ok). |
697 | * | |
e65ce2a5 CB |
698 | * If the inode has been found through an idmapped mount the user namespace of |
699 | * the vfsmount must be passed through @mnt_userns. This function will then | |
700 | * take care to map the inode according to @mnt_userns before checking | |
701 | * permissions. On non-idmapped mounts or if permission checking is to be | |
702 | * performed on the raw inode simply passs init_user_ns. | |
703 | * | |
07393101 JK |
704 | * Called from set_acl inode operations. |
705 | */ | |
e65ce2a5 CB |
706 | int posix_acl_update_mode(struct user_namespace *mnt_userns, |
707 | struct inode *inode, umode_t *mode_p, | |
07393101 JK |
708 | struct posix_acl **acl) |
709 | { | |
710 | umode_t mode = inode->i_mode; | |
711 | int error; | |
712 | ||
713 | error = posix_acl_equiv_mode(*acl, &mode); | |
714 | if (error < 0) | |
715 | return error; | |
716 | if (error == 0) | |
717 | *acl = NULL; | |
e933c15f | 718 | if (!vfsgid_in_group_p(i_gid_into_vfsgid(mnt_userns, inode)) && |
e65ce2a5 | 719 | !capable_wrt_inode_uidgid(mnt_userns, inode, CAP_FSETID)) |
07393101 JK |
720 | mode &= ~S_ISGID; |
721 | *mode_p = mode; | |
722 | return 0; | |
723 | } | |
724 | EXPORT_SYMBOL(posix_acl_update_mode); | |
725 | ||
5c8ebd57 CH |
726 | /* |
727 | * Fix up the uids and gids in posix acl extended attributes in place. | |
728 | */ | |
985a6d0b | 729 | static int posix_acl_fix_xattr_common(const void *value, size_t size) |
0c5fd887 | 730 | { |
985a6d0b | 731 | const struct posix_acl_xattr_header *header = value; |
0c5fd887 CB |
732 | int count; |
733 | ||
734 | if (!header) | |
735 | return -EINVAL; | |
736 | if (size < sizeof(struct posix_acl_xattr_header)) | |
737 | return -EINVAL; | |
738 | if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION)) | |
985a6d0b | 739 | return -EOPNOTSUPP; |
0c5fd887 CB |
740 | |
741 | count = posix_acl_xattr_count(size); | |
742 | if (count < 0) | |
743 | return -EINVAL; | |
744 | if (count == 0) | |
985a6d0b | 745 | return 0; |
0c5fd887 CB |
746 | |
747 | return count; | |
748 | } | |
749 | ||
750 | void posix_acl_getxattr_idmapped_mnt(struct user_namespace *mnt_userns, | |
751 | const struct inode *inode, | |
752 | void *value, size_t size) | |
5c8ebd57 | 753 | { |
2211d5ba AG |
754 | struct posix_acl_xattr_header *header = value; |
755 | struct posix_acl_xattr_entry *entry = (void *)(header + 1), *end; | |
abfcf55d | 756 | struct user_namespace *fs_userns = i_user_ns(inode); |
5c8ebd57 | 757 | int count; |
0c5fd887 CB |
758 | vfsuid_t vfsuid; |
759 | vfsgid_t vfsgid; | |
5c8ebd57 CH |
760 | kuid_t uid; |
761 | kgid_t gid; | |
762 | ||
0c5fd887 | 763 | if (no_idmapping(mnt_userns, i_user_ns(inode))) |
5c8ebd57 | 764 | return; |
0c5fd887 CB |
765 | |
766 | count = posix_acl_fix_xattr_common(value, size); | |
985a6d0b | 767 | if (count <= 0) |
5c8ebd57 | 768 | return; |
0c5fd887 CB |
769 | |
770 | for (end = entry + count; entry != end; entry++) { | |
771 | switch (le16_to_cpu(entry->e_tag)) { | |
772 | case ACL_USER: | |
773 | uid = make_kuid(&init_user_ns, le32_to_cpu(entry->e_id)); | |
abfcf55d | 774 | vfsuid = make_vfsuid(mnt_userns, fs_userns, uid); |
0c5fd887 CB |
775 | entry->e_id = cpu_to_le32(from_kuid(&init_user_ns, |
776 | vfsuid_into_kuid(vfsuid))); | |
777 | break; | |
778 | case ACL_GROUP: | |
779 | gid = make_kgid(&init_user_ns, le32_to_cpu(entry->e_id)); | |
abfcf55d | 780 | vfsgid = make_vfsgid(mnt_userns, fs_userns, gid); |
0c5fd887 CB |
781 | entry->e_id = cpu_to_le32(from_kgid(&init_user_ns, |
782 | vfsgid_into_kgid(vfsgid))); | |
783 | break; | |
784 | default: | |
785 | break; | |
786 | } | |
787 | } | |
788 | } | |
789 | ||
0c5fd887 CB |
790 | static void posix_acl_fix_xattr_userns( |
791 | struct user_namespace *to, struct user_namespace *from, | |
792 | void *value, size_t size) | |
793 | { | |
794 | struct posix_acl_xattr_header *header = value; | |
795 | struct posix_acl_xattr_entry *entry = (void *)(header + 1), *end; | |
796 | int count; | |
797 | kuid_t uid; | |
798 | kgid_t gid; | |
799 | ||
800 | count = posix_acl_fix_xattr_common(value, size); | |
985a6d0b | 801 | if (count <= 0) |
5c8ebd57 CH |
802 | return; |
803 | ||
804 | for (end = entry + count; entry != end; entry++) { | |
805 | switch(le16_to_cpu(entry->e_tag)) { | |
806 | case ACL_USER: | |
807 | uid = make_kuid(from, le32_to_cpu(entry->e_id)); | |
808 | entry->e_id = cpu_to_le32(from_kuid(to, uid)); | |
809 | break; | |
810 | case ACL_GROUP: | |
811 | gid = make_kgid(from, le32_to_cpu(entry->e_id)); | |
812 | entry->e_id = cpu_to_le32(from_kgid(to, gid)); | |
813 | break; | |
814 | default: | |
815 | break; | |
816 | } | |
817 | } | |
818 | } | |
819 | ||
0c5fd887 | 820 | void posix_acl_fix_xattr_from_user(void *value, size_t size) |
5c8ebd57 CH |
821 | { |
822 | struct user_namespace *user_ns = current_user_ns(); | |
0c5fd887 | 823 | if (user_ns == &init_user_ns) |
5c8ebd57 | 824 | return; |
0c5fd887 | 825 | posix_acl_fix_xattr_userns(&init_user_ns, user_ns, value, size); |
5c8ebd57 CH |
826 | } |
827 | ||
0c5fd887 | 828 | void posix_acl_fix_xattr_to_user(void *value, size_t size) |
5c8ebd57 CH |
829 | { |
830 | struct user_namespace *user_ns = current_user_ns(); | |
0c5fd887 | 831 | if (user_ns == &init_user_ns) |
5c8ebd57 | 832 | return; |
0c5fd887 | 833 | posix_acl_fix_xattr_userns(user_ns, &init_user_ns, value, size); |
5c8ebd57 CH |
834 | } |
835 | ||
6b70fe06 CB |
836 | /** |
837 | * make_posix_acl - convert POSIX ACLs from uapi to VFS format using the | |
838 | * provided callbacks to map ACL_{GROUP,USER} entries into the | |
839 | * appropriate format | |
840 | * @mnt_userns: the mount's idmapping | |
841 | * @fs_userns: the filesystem's idmapping | |
842 | * @value: the uapi representation of POSIX ACLs | |
843 | * @size: the size of @void | |
844 | * @uid_cb: callback to use for mapping the uid stored in ACL_USER entries | |
845 | * @gid_cb: callback to use for mapping the gid stored in ACL_GROUP entries | |
846 | * | |
847 | * The make_posix_acl() helper is an abstraction to translate from uapi format | |
848 | * into the VFS format allowing the caller to specific callbacks to map | |
849 | * ACL_{GROUP,USER} entries into the expected format. This is used in | |
850 | * posix_acl_from_xattr() and vfs_set_acl_prepare() and avoids pointless code | |
851 | * duplication. | |
852 | * | |
853 | * Return: Allocated struct posix_acl on success, NULL for a valid header but | |
854 | * without actual POSIX ACL entries, or ERR_PTR() encoded error code. | |
5c8ebd57 | 855 | */ |
6b70fe06 CB |
856 | static struct posix_acl *make_posix_acl(struct user_namespace *mnt_userns, |
857 | struct user_namespace *fs_userns, const void *value, size_t size, | |
858 | kuid_t (*uid_cb)(struct user_namespace *, struct user_namespace *, | |
859 | const struct posix_acl_xattr_entry *), | |
860 | kgid_t (*gid_cb)(struct user_namespace *, struct user_namespace *, | |
861 | const struct posix_acl_xattr_entry *)) | |
5c8ebd57 | 862 | { |
2211d5ba AG |
863 | const struct posix_acl_xattr_header *header = value; |
864 | const struct posix_acl_xattr_entry *entry = (const void *)(header + 1), *end; | |
5c8ebd57 CH |
865 | int count; |
866 | struct posix_acl *acl; | |
867 | struct posix_acl_entry *acl_e; | |
868 | ||
985a6d0b | 869 | count = posix_acl_fix_xattr_common(value, size); |
5c8ebd57 | 870 | if (count < 0) |
985a6d0b | 871 | return ERR_PTR(count); |
5c8ebd57 CH |
872 | if (count == 0) |
873 | return NULL; | |
874 | ||
875 | acl = posix_acl_alloc(count, GFP_NOFS); | |
876 | if (!acl) | |
877 | return ERR_PTR(-ENOMEM); | |
878 | acl_e = acl->a_entries; | |
879 | ||
880 | for (end = entry + count; entry != end; acl_e++, entry++) { | |
881 | acl_e->e_tag = le16_to_cpu(entry->e_tag); | |
882 | acl_e->e_perm = le16_to_cpu(entry->e_perm); | |
883 | ||
884 | switch(acl_e->e_tag) { | |
885 | case ACL_USER_OBJ: | |
886 | case ACL_GROUP_OBJ: | |
887 | case ACL_MASK: | |
888 | case ACL_OTHER: | |
889 | break; | |
890 | ||
891 | case ACL_USER: | |
6b70fe06 | 892 | acl_e->e_uid = uid_cb(mnt_userns, fs_userns, entry); |
5c8ebd57 CH |
893 | if (!uid_valid(acl_e->e_uid)) |
894 | goto fail; | |
895 | break; | |
896 | case ACL_GROUP: | |
6b70fe06 | 897 | acl_e->e_gid = gid_cb(mnt_userns, fs_userns, entry); |
5c8ebd57 CH |
898 | if (!gid_valid(acl_e->e_gid)) |
899 | goto fail; | |
900 | break; | |
901 | ||
902 | default: | |
903 | goto fail; | |
904 | } | |
905 | } | |
906 | return acl; | |
907 | ||
908 | fail: | |
909 | posix_acl_release(acl); | |
910 | return ERR_PTR(-EINVAL); | |
911 | } | |
6b70fe06 CB |
912 | |
913 | /** | |
914 | * vfs_set_acl_prepare_kuid - map ACL_USER uid according to mount- and | |
915 | * filesystem idmapping | |
916 | * @mnt_userns: the mount's idmapping | |
917 | * @fs_userns: the filesystem's idmapping | |
918 | * @e: a ACL_USER entry in POSIX ACL uapi format | |
919 | * | |
920 | * The uid stored as ACL_USER entry in @e is a kuid_t stored as a raw {g,u}id | |
921 | * value. The vfs_set_acl_prepare_kuid() will recover the kuid_t through | |
922 | * KUIDT_INIT() and then map it according to the idmapped mount. The resulting | |
923 | * kuid_t is the value which the filesystem can map up into a raw backing store | |
924 | * id in the filesystem's idmapping. | |
925 | * | |
926 | * This is used in vfs_set_acl_prepare() to generate the proper VFS | |
927 | * representation of POSIX ACLs with ACL_USER entries during setxattr(). | |
928 | * | |
929 | * Return: A kuid in @fs_userns for the uid stored in @e. | |
930 | */ | |
931 | static inline kuid_t | |
932 | vfs_set_acl_prepare_kuid(struct user_namespace *mnt_userns, | |
933 | struct user_namespace *fs_userns, | |
934 | const struct posix_acl_xattr_entry *e) | |
935 | { | |
936 | kuid_t kuid = KUIDT_INIT(le32_to_cpu(e->e_id)); | |
937 | return from_vfsuid(mnt_userns, fs_userns, VFSUIDT_INIT(kuid)); | |
938 | } | |
939 | ||
940 | /** | |
941 | * vfs_set_acl_prepare_kgid - map ACL_GROUP gid according to mount- and | |
942 | * filesystem idmapping | |
943 | * @mnt_userns: the mount's idmapping | |
944 | * @fs_userns: the filesystem's idmapping | |
945 | * @e: a ACL_GROUP entry in POSIX ACL uapi format | |
946 | * | |
947 | * The gid stored as ACL_GROUP entry in @e is a kgid_t stored as a raw {g,u}id | |
948 | * value. The vfs_set_acl_prepare_kgid() will recover the kgid_t through | |
949 | * KGIDT_INIT() and then map it according to the idmapped mount. The resulting | |
950 | * kgid_t is the value which the filesystem can map up into a raw backing store | |
951 | * id in the filesystem's idmapping. | |
952 | * | |
953 | * This is used in vfs_set_acl_prepare() to generate the proper VFS | |
954 | * representation of POSIX ACLs with ACL_GROUP entries during setxattr(). | |
955 | * | |
956 | * Return: A kgid in @fs_userns for the gid stored in @e. | |
957 | */ | |
958 | static inline kgid_t | |
959 | vfs_set_acl_prepare_kgid(struct user_namespace *mnt_userns, | |
960 | struct user_namespace *fs_userns, | |
961 | const struct posix_acl_xattr_entry *e) | |
962 | { | |
963 | kgid_t kgid = KGIDT_INIT(le32_to_cpu(e->e_id)); | |
964 | return from_vfsgid(mnt_userns, fs_userns, VFSGIDT_INIT(kgid)); | |
965 | } | |
966 | ||
967 | /** | |
968 | * vfs_set_acl_prepare - convert POSIX ACLs from uapi to VFS format taking | |
969 | * mount and filesystem idmappings into account | |
970 | * @mnt_userns: the mount's idmapping | |
971 | * @fs_userns: the filesystem's idmapping | |
972 | * @value: the uapi representation of POSIX ACLs | |
973 | * @size: the size of @void | |
974 | * | |
975 | * When setting POSIX ACLs with ACL_{GROUP,USER} entries they need to be | |
976 | * mapped according to the relevant mount- and filesystem idmapping. It is | |
977 | * important that the ACL_{GROUP,USER} entries in struct posix_acl will be | |
978 | * mapped into k{g,u}id_t that are supposed to be mapped up in the filesystem | |
979 | * idmapping. This is crucial since the resulting struct posix_acl might be | |
980 | * cached filesystem wide. The vfs_set_acl_prepare() function will take care to | |
981 | * perform all necessary idmappings. | |
982 | * | |
983 | * Note, that since basically forever the {g,u}id values encoded as | |
984 | * ACL_{GROUP,USER} entries in the uapi POSIX ACLs passed via @value contain | |
985 | * values that have been mapped according to the caller's idmapping. In other | |
986 | * words, POSIX ACLs passed in uapi format as @value during setxattr() contain | |
987 | * {g,u}id values in their ACL_{GROUP,USER} entries that should actually have | |
988 | * been stored as k{g,u}id_t. | |
989 | * | |
990 | * This means, vfs_set_acl_prepare() needs to first recover the k{g,u}id_t by | |
991 | * calling K{G,U}IDT_INIT(). Afterwards they can be interpreted as vfs{g,u}id_t | |
992 | * through from_vfs{g,u}id() to account for any idmapped mounts. The | |
993 | * vfs_set_acl_prepare_k{g,u}id() helpers will take care to generate the | |
994 | * correct k{g,u}id_t. | |
995 | * | |
996 | * The filesystem will then receive the POSIX ACLs ready to be cached | |
997 | * filesystem wide and ready to be written to the backing store taking the | |
998 | * filesystem's idmapping into account. | |
999 | * | |
1000 | * Return: Allocated struct posix_acl on success, NULL for a valid header but | |
1001 | * without actual POSIX ACL entries, or ERR_PTR() encoded error code. | |
1002 | */ | |
1003 | struct posix_acl *vfs_set_acl_prepare(struct user_namespace *mnt_userns, | |
1004 | struct user_namespace *fs_userns, | |
1005 | const void *value, size_t size) | |
1006 | { | |
1007 | return make_posix_acl(mnt_userns, fs_userns, value, size, | |
1008 | vfs_set_acl_prepare_kuid, | |
1009 | vfs_set_acl_prepare_kgid); | |
1010 | } | |
1011 | EXPORT_SYMBOL(vfs_set_acl_prepare); | |
1012 | ||
1013 | /** | |
1014 | * posix_acl_from_xattr_kuid - map ACL_USER uid into filesystem idmapping | |
1015 | * @mnt_userns: unused | |
1016 | * @fs_userns: the filesystem's idmapping | |
1017 | * @e: a ACL_USER entry in POSIX ACL uapi format | |
1018 | * | |
1019 | * Map the uid stored as ACL_USER entry in @e into the filesystem's idmapping. | |
1020 | * This is used in posix_acl_from_xattr() to generate the proper VFS | |
1021 | * representation of POSIX ACLs with ACL_USER entries. | |
1022 | * | |
1023 | * Return: A kuid in @fs_userns for the uid stored in @e. | |
1024 | */ | |
1025 | static inline kuid_t | |
1026 | posix_acl_from_xattr_kuid(struct user_namespace *mnt_userns, | |
1027 | struct user_namespace *fs_userns, | |
1028 | const struct posix_acl_xattr_entry *e) | |
1029 | { | |
1030 | return make_kuid(fs_userns, le32_to_cpu(e->e_id)); | |
1031 | } | |
1032 | ||
1033 | /** | |
1034 | * posix_acl_from_xattr_kgid - map ACL_GROUP gid into filesystem idmapping | |
1035 | * @mnt_userns: unused | |
1036 | * @fs_userns: the filesystem's idmapping | |
1037 | * @e: a ACL_GROUP entry in POSIX ACL uapi format | |
1038 | * | |
1039 | * Map the gid stored as ACL_GROUP entry in @e into the filesystem's idmapping. | |
1040 | * This is used in posix_acl_from_xattr() to generate the proper VFS | |
1041 | * representation of POSIX ACLs with ACL_GROUP entries. | |
1042 | * | |
1043 | * Return: A kgid in @fs_userns for the gid stored in @e. | |
1044 | */ | |
1045 | static inline kgid_t | |
1046 | posix_acl_from_xattr_kgid(struct user_namespace *mnt_userns, | |
1047 | struct user_namespace *fs_userns, | |
1048 | const struct posix_acl_xattr_entry *e) | |
1049 | { | |
1050 | return make_kgid(fs_userns, le32_to_cpu(e->e_id)); | |
1051 | } | |
1052 | ||
1053 | /** | |
1054 | * posix_acl_from_xattr - convert POSIX ACLs from backing store to VFS format | |
1055 | * @fs_userns: the filesystem's idmapping | |
1056 | * @value: the uapi representation of POSIX ACLs | |
1057 | * @size: the size of @void | |
1058 | * | |
1059 | * Filesystems that store POSIX ACLs in the unaltered uapi format should use | |
1060 | * posix_acl_from_xattr() when reading them from the backing store and | |
1061 | * converting them into the struct posix_acl VFS format. The helper is | |
cac2f8b8 CB |
1062 | * specifically intended to be called from the ->get_inode_acl() inode |
1063 | * operation. | |
6b70fe06 CB |
1064 | * |
1065 | * The posix_acl_from_xattr() function will map the raw {g,u}id values stored | |
1066 | * in ACL_{GROUP,USER} entries into the filesystem idmapping in @fs_userns. The | |
1067 | * posix_acl_from_xattr_k{g,u}id() helpers will take care to generate the | |
1068 | * correct k{g,u}id_t. The returned struct posix_acl can be cached. | |
1069 | * | |
1070 | * Note that posix_acl_from_xattr() does not take idmapped mounts into account. | |
cac2f8b8 CB |
1071 | * If it did it calling is from the ->get_inode_acl() inode operation would |
1072 | * return POSIX ACLs mapped according to an idmapped mount which would mean | |
1073 | * that the value couldn't be cached for the filesystem. Idmapped mounts are | |
1074 | * taken into account on the fly during permission checking or right at the VFS | |
1075 | * - userspace boundary before reporting them to the user. | |
6b70fe06 CB |
1076 | * |
1077 | * Return: Allocated struct posix_acl on success, NULL for a valid header but | |
1078 | * without actual POSIX ACL entries, or ERR_PTR() encoded error code. | |
1079 | */ | |
1080 | struct posix_acl * | |
1081 | posix_acl_from_xattr(struct user_namespace *fs_userns, | |
1082 | const void *value, size_t size) | |
1083 | { | |
1084 | return make_posix_acl(&init_user_ns, fs_userns, value, size, | |
1085 | posix_acl_from_xattr_kuid, | |
1086 | posix_acl_from_xattr_kgid); | |
1087 | } | |
5c8ebd57 CH |
1088 | EXPORT_SYMBOL (posix_acl_from_xattr); |
1089 | ||
1090 | /* | |
1091 | * Convert from in-memory to extended attribute representation. | |
1092 | */ | |
1093 | int | |
1094 | posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl, | |
1095 | void *buffer, size_t size) | |
1096 | { | |
2211d5ba AG |
1097 | struct posix_acl_xattr_header *ext_acl = buffer; |
1098 | struct posix_acl_xattr_entry *ext_entry; | |
5c8ebd57 CH |
1099 | int real_size, n; |
1100 | ||
1101 | real_size = posix_acl_xattr_size(acl->a_count); | |
1102 | if (!buffer) | |
1103 | return real_size; | |
1104 | if (real_size > size) | |
1105 | return -ERANGE; | |
47ba9734 | 1106 | |
2211d5ba | 1107 | ext_entry = (void *)(ext_acl + 1); |
5c8ebd57 CH |
1108 | ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION); |
1109 | ||
1110 | for (n=0; n < acl->a_count; n++, ext_entry++) { | |
1111 | const struct posix_acl_entry *acl_e = &acl->a_entries[n]; | |
1112 | ext_entry->e_tag = cpu_to_le16(acl_e->e_tag); | |
1113 | ext_entry->e_perm = cpu_to_le16(acl_e->e_perm); | |
1114 | switch(acl_e->e_tag) { | |
1115 | case ACL_USER: | |
1116 | ext_entry->e_id = | |
1117 | cpu_to_le32(from_kuid(user_ns, acl_e->e_uid)); | |
1118 | break; | |
1119 | case ACL_GROUP: | |
1120 | ext_entry->e_id = | |
1121 | cpu_to_le32(from_kgid(user_ns, acl_e->e_gid)); | |
1122 | break; | |
1123 | default: | |
1124 | ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID); | |
1125 | break; | |
1126 | } | |
1127 | } | |
1128 | return real_size; | |
1129 | } | |
1130 | EXPORT_SYMBOL (posix_acl_to_xattr); | |
2aeccbe9 | 1131 | |
4f353ba4 CB |
1132 | /** |
1133 | * vfs_posix_acl_to_xattr - convert from kernel to userspace representation | |
1134 | * @mnt_userns: user namespace of the mount | |
1135 | * @inode: inode the posix acls are set on | |
1136 | * @acl: the posix acls as represented by the vfs | |
1137 | * @buffer: the buffer into which to convert @acl | |
1138 | * @size: size of @buffer | |
1139 | * | |
1140 | * This converts @acl from the VFS representation in the filesystem idmapping | |
1141 | * to the uapi form reportable to userspace. And mount and caller idmappings | |
1142 | * are handled appropriately. | |
1143 | * | |
1144 | * Return: On success, the size of the stored uapi posix acls, on error a | |
1145 | * negative errno. | |
1146 | */ | |
1147 | ssize_t vfs_posix_acl_to_xattr(struct user_namespace *mnt_userns, | |
1148 | struct inode *inode, const struct posix_acl *acl, | |
1149 | void *buffer, size_t size) | |
1150 | ||
1151 | { | |
1152 | struct posix_acl_xattr_header *ext_acl = buffer; | |
1153 | struct posix_acl_xattr_entry *ext_entry; | |
1154 | struct user_namespace *fs_userns, *caller_userns; | |
1155 | ssize_t real_size, n; | |
1156 | vfsuid_t vfsuid; | |
1157 | vfsgid_t vfsgid; | |
1158 | ||
1159 | real_size = posix_acl_xattr_size(acl->a_count); | |
1160 | if (!buffer) | |
1161 | return real_size; | |
1162 | if (real_size > size) | |
1163 | return -ERANGE; | |
1164 | ||
1165 | ext_entry = (void *)(ext_acl + 1); | |
1166 | ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION); | |
1167 | ||
1168 | fs_userns = i_user_ns(inode); | |
1169 | caller_userns = current_user_ns(); | |
1170 | for (n=0; n < acl->a_count; n++, ext_entry++) { | |
1171 | const struct posix_acl_entry *acl_e = &acl->a_entries[n]; | |
1172 | ext_entry->e_tag = cpu_to_le16(acl_e->e_tag); | |
1173 | ext_entry->e_perm = cpu_to_le16(acl_e->e_perm); | |
1174 | switch(acl_e->e_tag) { | |
1175 | case ACL_USER: | |
1176 | vfsuid = make_vfsuid(mnt_userns, fs_userns, acl_e->e_uid); | |
1177 | ext_entry->e_id = cpu_to_le32(from_kuid( | |
1178 | caller_userns, vfsuid_into_kuid(vfsuid))); | |
1179 | break; | |
1180 | case ACL_GROUP: | |
1181 | vfsgid = make_vfsgid(mnt_userns, fs_userns, acl_e->e_gid); | |
1182 | ext_entry->e_id = cpu_to_le32(from_kgid( | |
1183 | caller_userns, vfsgid_into_kgid(vfsgid))); | |
1184 | break; | |
1185 | default: | |
1186 | ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID); | |
1187 | break; | |
1188 | } | |
1189 | } | |
1190 | return real_size; | |
1191 | } | |
1192 | ||
2aeccbe9 | 1193 | static int |
d9a82a04 | 1194 | posix_acl_xattr_get(const struct xattr_handler *handler, |
b296821a AV |
1195 | struct dentry *unused, struct inode *inode, |
1196 | const char *name, void *value, size_t size) | |
2aeccbe9 CH |
1197 | { |
1198 | struct posix_acl *acl; | |
1199 | int error; | |
1200 | ||
b296821a | 1201 | if (!IS_POSIXACL(inode)) |
2aeccbe9 | 1202 | return -EOPNOTSUPP; |
b296821a | 1203 | if (S_ISLNK(inode->i_mode)) |
2aeccbe9 CH |
1204 | return -EOPNOTSUPP; |
1205 | ||
cac2f8b8 | 1206 | acl = get_inode_acl(inode, handler->flags); |
2aeccbe9 CH |
1207 | if (IS_ERR(acl)) |
1208 | return PTR_ERR(acl); | |
1209 | if (acl == NULL) | |
1210 | return -ENODATA; | |
1211 | ||
1212 | error = posix_acl_to_xattr(&init_user_ns, acl, value, size); | |
1213 | posix_acl_release(acl); | |
1214 | ||
1215 | return error; | |
1216 | } | |
1217 | ||
485e71e8 | 1218 | int |
138060ba | 1219 | set_posix_acl(struct user_namespace *mnt_userns, struct dentry *dentry, |
e65ce2a5 | 1220 | int type, struct posix_acl *acl) |
2aeccbe9 | 1221 | { |
138060ba CB |
1222 | struct inode *inode = d_inode(dentry); |
1223 | ||
2aeccbe9 CH |
1224 | if (!IS_POSIXACL(inode)) |
1225 | return -EOPNOTSUPP; | |
1226 | if (!inode->i_op->set_acl) | |
1227 | return -EOPNOTSUPP; | |
1228 | ||
485e71e8 AG |
1229 | if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode)) |
1230 | return acl ? -EACCES : 0; | |
e65ce2a5 | 1231 | if (!inode_owner_or_capable(mnt_userns, inode)) |
2aeccbe9 CH |
1232 | return -EPERM; |
1233 | ||
485e71e8 | 1234 | if (acl) { |
a867d734 | 1235 | int ret = posix_acl_valid(inode->i_sb->s_user_ns, acl); |
485e71e8 AG |
1236 | if (ret) |
1237 | return ret; | |
1238 | } | |
138060ba | 1239 | return inode->i_op->set_acl(mnt_userns, dentry, acl, type); |
485e71e8 AG |
1240 | } |
1241 | EXPORT_SYMBOL(set_posix_acl); | |
1242 | ||
1243 | static int | |
1244 | posix_acl_xattr_set(const struct xattr_handler *handler, | |
e65ce2a5 | 1245 | struct user_namespace *mnt_userns, |
138060ba | 1246 | struct dentry *dentry, struct inode *inode, |
e65ce2a5 CB |
1247 | const char *name, const void *value, size_t size, |
1248 | int flags) | |
485e71e8 AG |
1249 | { |
1250 | struct posix_acl *acl = NULL; | |
1251 | int ret; | |
1252 | ||
2aeccbe9 | 1253 | if (value) { |
52edb408 CB |
1254 | /* |
1255 | * By the time we end up here the {g,u}ids stored in | |
1256 | * ACL_{GROUP,USER} have already been mapped according to the | |
1257 | * caller's idmapping. The vfs_set_acl_prepare() helper will | |
1258 | * recover them and take idmapped mounts into account. The | |
0978c7c4 | 1259 | * filesystem will receive the POSIX ACLs in the correct |
52edb408 CB |
1260 | * format ready to be cached or written to the backing store |
1261 | * taking the filesystem idmapping into account. | |
1262 | */ | |
1263 | acl = vfs_set_acl_prepare(mnt_userns, i_user_ns(inode), | |
1264 | value, size); | |
2aeccbe9 CH |
1265 | if (IS_ERR(acl)) |
1266 | return PTR_ERR(acl); | |
2aeccbe9 | 1267 | } |
138060ba | 1268 | ret = set_posix_acl(mnt_userns, dentry, handler->flags, acl); |
2aeccbe9 CH |
1269 | posix_acl_release(acl); |
1270 | return ret; | |
1271 | } | |
1272 | ||
764a5c6b AG |
1273 | static bool |
1274 | posix_acl_xattr_list(struct dentry *dentry) | |
2aeccbe9 | 1275 | { |
764a5c6b | 1276 | return IS_POSIXACL(d_backing_inode(dentry)); |
2aeccbe9 CH |
1277 | } |
1278 | ||
1279 | const struct xattr_handler posix_acl_access_xattr_handler = { | |
98e9cb57 | 1280 | .name = XATTR_NAME_POSIX_ACL_ACCESS, |
2aeccbe9 CH |
1281 | .flags = ACL_TYPE_ACCESS, |
1282 | .list = posix_acl_xattr_list, | |
1283 | .get = posix_acl_xattr_get, | |
1284 | .set = posix_acl_xattr_set, | |
1285 | }; | |
1286 | EXPORT_SYMBOL_GPL(posix_acl_access_xattr_handler); | |
1287 | ||
1288 | const struct xattr_handler posix_acl_default_xattr_handler = { | |
98e9cb57 | 1289 | .name = XATTR_NAME_POSIX_ACL_DEFAULT, |
2aeccbe9 CH |
1290 | .flags = ACL_TYPE_DEFAULT, |
1291 | .list = posix_acl_xattr_list, | |
1292 | .get = posix_acl_xattr_get, | |
1293 | .set = posix_acl_xattr_set, | |
1294 | }; | |
1295 | EXPORT_SYMBOL_GPL(posix_acl_default_xattr_handler); | |
feda821e | 1296 | |
138060ba | 1297 | int simple_set_acl(struct user_namespace *mnt_userns, struct dentry *dentry, |
549c7297 | 1298 | struct posix_acl *acl, int type) |
feda821e CH |
1299 | { |
1300 | int error; | |
138060ba | 1301 | struct inode *inode = d_inode(dentry); |
feda821e CH |
1302 | |
1303 | if (type == ACL_TYPE_ACCESS) { | |
549c7297 | 1304 | error = posix_acl_update_mode(mnt_userns, inode, |
497de07d GZ |
1305 | &inode->i_mode, &acl); |
1306 | if (error) | |
1307 | return error; | |
feda821e CH |
1308 | } |
1309 | ||
078cd827 | 1310 | inode->i_ctime = current_time(inode); |
36f05cab JL |
1311 | if (IS_I_VERSION(inode)) |
1312 | inode_inc_iversion(inode); | |
feda821e CH |
1313 | set_cached_acl(inode, type, acl); |
1314 | return 0; | |
1315 | } | |
1316 | ||
1317 | int simple_acl_create(struct inode *dir, struct inode *inode) | |
1318 | { | |
1319 | struct posix_acl *default_acl, *acl; | |
1320 | int error; | |
1321 | ||
1322 | error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl); | |
1323 | if (error) | |
1324 | return error; | |
1325 | ||
1326 | set_cached_acl(inode, ACL_TYPE_DEFAULT, default_acl); | |
1327 | set_cached_acl(inode, ACL_TYPE_ACCESS, acl); | |
1328 | ||
1329 | if (default_acl) | |
1330 | posix_acl_release(default_acl); | |
1331 | if (acl) | |
1332 | posix_acl_release(acl); | |
1333 | return 0; | |
1334 | } | |
e4cc9163 CB |
1335 | |
1336 | static int vfs_set_acl_idmapped_mnt(struct user_namespace *mnt_userns, | |
1337 | struct user_namespace *fs_userns, | |
1338 | struct posix_acl *acl) | |
1339 | { | |
1340 | for (int n = 0; n < acl->a_count; n++) { | |
1341 | struct posix_acl_entry *acl_e = &acl->a_entries[n]; | |
1342 | ||
1343 | switch (acl_e->e_tag) { | |
1344 | case ACL_USER: | |
1345 | acl_e->e_uid = from_vfsuid(mnt_userns, fs_userns, | |
1346 | VFSUIDT_INIT(acl_e->e_uid)); | |
1347 | break; | |
1348 | case ACL_GROUP: | |
1349 | acl_e->e_gid = from_vfsgid(mnt_userns, fs_userns, | |
1350 | VFSGIDT_INIT(acl_e->e_gid)); | |
1351 | break; | |
1352 | } | |
1353 | } | |
1354 | ||
1355 | return 0; | |
1356 | } | |
1357 | ||
1358 | /** | |
1359 | * vfs_set_acl - set posix acls | |
1360 | * @mnt_userns: user namespace of the mount | |
1361 | * @dentry: the dentry based on which to set the posix acls | |
1362 | * @acl_name: the name of the posix acl | |
1363 | * @kacl: the posix acls in the appropriate VFS format | |
1364 | * | |
1365 | * This function sets @kacl. The caller must all posix_acl_release() on @kacl | |
1366 | * afterwards. | |
1367 | * | |
1368 | * Return: On success 0, on error negative errno. | |
1369 | */ | |
1370 | int vfs_set_acl(struct user_namespace *mnt_userns, struct dentry *dentry, | |
1371 | const char *acl_name, struct posix_acl *kacl) | |
1372 | { | |
1373 | int acl_type; | |
1374 | int error; | |
1375 | struct inode *inode = d_inode(dentry); | |
1376 | struct inode *delegated_inode = NULL; | |
1377 | ||
1378 | acl_type = posix_acl_type(acl_name); | |
1379 | if (acl_type < 0) | |
1380 | return -EINVAL; | |
1381 | ||
1382 | if (kacl) { | |
1383 | /* | |
1384 | * If we're on an idmapped mount translate from mount specific | |
1385 | * vfs{g,u}id_t into global filesystem k{g,u}id_t. | |
1386 | * Afterwards we can cache the POSIX ACLs filesystem wide and - | |
1387 | * if this is a filesystem with a backing store - ultimately | |
1388 | * translate them to backing store values. | |
1389 | */ | |
1390 | error = vfs_set_acl_idmapped_mnt(mnt_userns, i_user_ns(inode), kacl); | |
1391 | if (error) | |
1392 | return error; | |
1393 | } | |
1394 | ||
1395 | retry_deleg: | |
1396 | inode_lock(inode); | |
1397 | ||
1398 | /* | |
1399 | * We only care about restrictions the inode struct itself places upon | |
1400 | * us otherwise POSIX ACLs aren't subject to any VFS restrictions. | |
1401 | */ | |
1402 | error = may_write_xattr(mnt_userns, inode); | |
1403 | if (error) | |
1404 | goto out_inode_unlock; | |
1405 | ||
1406 | error = security_inode_set_acl(mnt_userns, dentry, acl_name, kacl); | |
1407 | if (error) | |
1408 | goto out_inode_unlock; | |
1409 | ||
1410 | error = try_break_deleg(inode, &delegated_inode); | |
1411 | if (error) | |
1412 | goto out_inode_unlock; | |
1413 | ||
1414 | if (inode->i_opflags & IOP_XATTR) | |
1415 | error = set_posix_acl(mnt_userns, dentry, acl_type, kacl); | |
1416 | else if (unlikely(is_bad_inode(inode))) | |
1417 | error = -EIO; | |
1418 | else | |
1419 | error = -EOPNOTSUPP; | |
1420 | if (!error) { | |
1421 | fsnotify_xattr(dentry); | |
1422 | evm_inode_post_set_acl(dentry, acl_name, kacl); | |
1423 | } | |
1424 | ||
1425 | out_inode_unlock: | |
1426 | inode_unlock(inode); | |
1427 | ||
1428 | if (delegated_inode) { | |
1429 | error = break_deleg_wait(&delegated_inode); | |
1430 | if (!error) | |
1431 | goto retry_deleg; | |
1432 | } | |
1433 | ||
1434 | return error; | |
1435 | } | |
1436 | EXPORT_SYMBOL_GPL(vfs_set_acl); | |
4f353ba4 CB |
1437 | |
1438 | /** | |
1439 | * vfs_get_acl - get posix acls | |
1440 | * @mnt_userns: user namespace of the mount | |
1441 | * @dentry: the dentry based on which to retrieve the posix acls | |
1442 | * @acl_name: the name of the posix acl | |
1443 | * | |
1444 | * This function retrieves @kacl from the filesystem. The caller must all | |
1445 | * posix_acl_release() on @kacl. | |
1446 | * | |
1447 | * Return: On success POSIX ACLs in VFS format, on error negative errno. | |
1448 | */ | |
1449 | struct posix_acl *vfs_get_acl(struct user_namespace *mnt_userns, | |
1450 | struct dentry *dentry, const char *acl_name) | |
1451 | { | |
1452 | struct inode *inode = d_inode(dentry); | |
1453 | struct posix_acl *acl; | |
1454 | int acl_type, error; | |
1455 | ||
1456 | acl_type = posix_acl_type(acl_name); | |
1457 | if (acl_type < 0) | |
1458 | return ERR_PTR(-EINVAL); | |
1459 | ||
1460 | /* | |
1461 | * The VFS has no restrictions on reading POSIX ACLs so calling | |
1462 | * something like xattr_permission() isn't needed. Only LSMs get a say. | |
1463 | */ | |
1464 | error = security_inode_get_acl(mnt_userns, dentry, acl_name); | |
1465 | if (error) | |
1466 | return ERR_PTR(error); | |
1467 | ||
1468 | if (!IS_POSIXACL(inode)) | |
1469 | return ERR_PTR(-EOPNOTSUPP); | |
1470 | if (S_ISLNK(inode->i_mode)) | |
1471 | return ERR_PTR(-EOPNOTSUPP); | |
1472 | ||
1473 | acl = __get_acl(mnt_userns, dentry, inode, acl_type); | |
1474 | if (IS_ERR(acl)) | |
1475 | return acl; | |
1476 | if (!acl) | |
1477 | return ERR_PTR(-ENODATA); | |
1478 | ||
1479 | return acl; | |
1480 | } | |
1481 | EXPORT_SYMBOL_GPL(vfs_get_acl); |