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> |
1da177e4 | 26 | |
04c57f45 | 27 | static struct posix_acl **acl_by_type(struct inode *inode, int type) |
0afaa120 AM |
28 | { |
29 | switch (type) { | |
30 | case ACL_TYPE_ACCESS: | |
31 | return &inode->i_acl; | |
32 | case ACL_TYPE_DEFAULT: | |
33 | return &inode->i_default_acl; | |
34 | default: | |
35 | BUG(); | |
36 | } | |
37 | } | |
0afaa120 AM |
38 | |
39 | struct posix_acl *get_cached_acl(struct inode *inode, int type) | |
40 | { | |
41 | struct posix_acl **p = acl_by_type(inode, type); | |
b8a7a3a6 AG |
42 | struct posix_acl *acl; |
43 | ||
44 | for (;;) { | |
45 | rcu_read_lock(); | |
46 | acl = rcu_dereference(*p); | |
47 | if (!acl || is_uncached_acl(acl) || | |
66717260 | 48 | refcount_inc_not_zero(&acl->a_refcount)) |
b8a7a3a6 AG |
49 | break; |
50 | rcu_read_unlock(); | |
51 | cpu_relax(); | |
0afaa120 | 52 | } |
b8a7a3a6 | 53 | rcu_read_unlock(); |
0afaa120 AM |
54 | return acl; |
55 | } | |
56 | EXPORT_SYMBOL(get_cached_acl); | |
57 | ||
58 | struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type) | |
59 | { | |
332f606b MS |
60 | struct posix_acl *acl = rcu_dereference(*acl_by_type(inode, type)); |
61 | ||
62 | if (acl == ACL_DONT_CACHE) { | |
63 | struct posix_acl *ret; | |
64 | ||
65 | ret = inode->i_op->get_acl(inode, type, LOOKUP_RCU); | |
66 | if (!IS_ERR(ret)) | |
67 | acl = ret; | |
68 | } | |
69 | ||
70 | return acl; | |
0afaa120 AM |
71 | } |
72 | EXPORT_SYMBOL(get_cached_acl_rcu); | |
73 | ||
74 | void set_cached_acl(struct inode *inode, int type, struct posix_acl *acl) | |
75 | { | |
76 | struct posix_acl **p = acl_by_type(inode, type); | |
77 | struct posix_acl *old; | |
b8a7a3a6 AG |
78 | |
79 | old = xchg(p, posix_acl_dup(acl)); | |
80 | if (!is_uncached_acl(old)) | |
0afaa120 AM |
81 | posix_acl_release(old); |
82 | } | |
83 | EXPORT_SYMBOL(set_cached_acl); | |
84 | ||
b8a7a3a6 | 85 | static void __forget_cached_acl(struct posix_acl **p) |
0afaa120 | 86 | { |
0afaa120 | 87 | struct posix_acl *old; |
b8a7a3a6 AG |
88 | |
89 | old = xchg(p, ACL_NOT_CACHED); | |
90 | if (!is_uncached_acl(old)) | |
0afaa120 AM |
91 | posix_acl_release(old); |
92 | } | |
b8a7a3a6 AG |
93 | |
94 | void forget_cached_acl(struct inode *inode, int type) | |
95 | { | |
96 | __forget_cached_acl(acl_by_type(inode, type)); | |
97 | } | |
0afaa120 AM |
98 | EXPORT_SYMBOL(forget_cached_acl); |
99 | ||
100 | void forget_all_cached_acls(struct inode *inode) | |
101 | { | |
b8a7a3a6 AG |
102 | __forget_cached_acl(&inode->i_acl); |
103 | __forget_cached_acl(&inode->i_default_acl); | |
0afaa120 AM |
104 | } |
105 | EXPORT_SYMBOL(forget_all_cached_acls); | |
1da177e4 | 106 | |
2982baa2 CH |
107 | struct posix_acl *get_acl(struct inode *inode, int type) |
108 | { | |
b8a7a3a6 AG |
109 | void *sentinel; |
110 | struct posix_acl **p; | |
2982baa2 CH |
111 | struct posix_acl *acl; |
112 | ||
b8a7a3a6 AG |
113 | /* |
114 | * The sentinel is used to detect when another operation like | |
115 | * set_cached_acl() or forget_cached_acl() races with get_acl(). | |
116 | * It is guaranteed that is_uncached_acl(sentinel) is true. | |
117 | */ | |
118 | ||
2982baa2 | 119 | acl = get_cached_acl(inode, type); |
b8a7a3a6 | 120 | if (!is_uncached_acl(acl)) |
2982baa2 CH |
121 | return acl; |
122 | ||
123 | if (!IS_POSIXACL(inode)) | |
124 | return NULL; | |
125 | ||
b8a7a3a6 AG |
126 | sentinel = uncached_acl_sentinel(current); |
127 | p = acl_by_type(inode, type); | |
128 | ||
129 | /* | |
130 | * If the ACL isn't being read yet, set our sentinel. Otherwise, the | |
131 | * current value of the ACL will not be ACL_NOT_CACHED and so our own | |
132 | * sentinel will not be set; another task will update the cache. We | |
133 | * could wait for that other task to complete its job, but it's easier | |
134 | * to just call ->get_acl to fetch the ACL ourself. (This is going to | |
135 | * be an unlikely race.) | |
136 | */ | |
137 | if (cmpxchg(p, ACL_NOT_CACHED, sentinel) != ACL_NOT_CACHED) | |
138 | /* fall through */ ; | |
139 | ||
2982baa2 | 140 | /* |
b8a7a3a6 AG |
141 | * Normally, the ACL returned by ->get_acl will be cached. |
142 | * A filesystem can prevent that by calling | |
143 | * forget_cached_acl(inode, type) in ->get_acl. | |
2982baa2 CH |
144 | * |
145 | * If the filesystem doesn't have a get_acl() function at all, we'll | |
146 | * just create the negative cache entry. | |
147 | */ | |
148 | if (!inode->i_op->get_acl) { | |
149 | set_cached_acl(inode, type, NULL); | |
150 | return NULL; | |
151 | } | |
0cad6246 | 152 | acl = inode->i_op->get_acl(inode, type, false); |
b8a7a3a6 AG |
153 | |
154 | if (IS_ERR(acl)) { | |
155 | /* | |
156 | * Remove our sentinel so that we don't block future attempts | |
157 | * to cache the ACL. | |
158 | */ | |
159 | cmpxchg(p, sentinel, ACL_NOT_CACHED); | |
160 | return acl; | |
161 | } | |
162 | ||
163 | /* | |
164 | * Cache the result, but only if our sentinel is still in place. | |
165 | */ | |
166 | posix_acl_dup(acl); | |
167 | if (unlikely(cmpxchg(p, sentinel, acl) != sentinel)) | |
168 | posix_acl_release(acl); | |
169 | return acl; | |
2982baa2 CH |
170 | } |
171 | EXPORT_SYMBOL(get_acl); | |
172 | ||
f61f6da0 CL |
173 | /* |
174 | * Init a fresh posix_acl | |
175 | */ | |
176 | void | |
177 | posix_acl_init(struct posix_acl *acl, int count) | |
178 | { | |
66717260 | 179 | refcount_set(&acl->a_refcount, 1); |
f61f6da0 CL |
180 | acl->a_count = count; |
181 | } | |
0afaa120 | 182 | EXPORT_SYMBOL(posix_acl_init); |
f61f6da0 | 183 | |
1da177e4 LT |
184 | /* |
185 | * Allocate a new ACL with the specified number of entries. | |
186 | */ | |
187 | struct posix_acl * | |
dd0fc66f | 188 | posix_acl_alloc(int count, gfp_t flags) |
1da177e4 LT |
189 | { |
190 | const size_t size = sizeof(struct posix_acl) + | |
191 | count * sizeof(struct posix_acl_entry); | |
192 | struct posix_acl *acl = kmalloc(size, flags); | |
f61f6da0 CL |
193 | if (acl) |
194 | posix_acl_init(acl, count); | |
1da177e4 LT |
195 | return acl; |
196 | } | |
0afaa120 | 197 | EXPORT_SYMBOL(posix_acl_alloc); |
1da177e4 LT |
198 | |
199 | /* | |
200 | * Clone an ACL. | |
201 | */ | |
edde854e | 202 | static struct posix_acl * |
dd0fc66f | 203 | posix_acl_clone(const struct posix_acl *acl, gfp_t flags) |
1da177e4 LT |
204 | { |
205 | struct posix_acl *clone = NULL; | |
206 | ||
207 | if (acl) { | |
208 | int size = sizeof(struct posix_acl) + acl->a_count * | |
209 | sizeof(struct posix_acl_entry); | |
52978be6 AD |
210 | clone = kmemdup(acl, size, flags); |
211 | if (clone) | |
66717260 | 212 | refcount_set(&clone->a_refcount, 1); |
1da177e4 LT |
213 | } |
214 | return clone; | |
215 | } | |
216 | ||
217 | /* | |
218 | * Check if an acl is valid. Returns 0 if it is, or -E... otherwise. | |
219 | */ | |
220 | int | |
0d4d717f | 221 | posix_acl_valid(struct user_namespace *user_ns, const struct posix_acl *acl) |
1da177e4 LT |
222 | { |
223 | const struct posix_acl_entry *pa, *pe; | |
224 | int state = ACL_USER_OBJ; | |
1da177e4 LT |
225 | int needs_mask = 0; |
226 | ||
227 | FOREACH_ACL_ENTRY(pa, acl, pe) { | |
228 | if (pa->e_perm & ~(ACL_READ|ACL_WRITE|ACL_EXECUTE)) | |
229 | return -EINVAL; | |
230 | switch (pa->e_tag) { | |
231 | case ACL_USER_OBJ: | |
232 | if (state == ACL_USER_OBJ) { | |
1da177e4 LT |
233 | state = ACL_USER; |
234 | break; | |
235 | } | |
236 | return -EINVAL; | |
237 | ||
238 | case ACL_USER: | |
239 | if (state != ACL_USER) | |
240 | return -EINVAL; | |
0d4d717f | 241 | if (!kuid_has_mapping(user_ns, pa->e_uid)) |
1da177e4 | 242 | return -EINVAL; |
1da177e4 LT |
243 | needs_mask = 1; |
244 | break; | |
245 | ||
246 | case ACL_GROUP_OBJ: | |
247 | if (state == ACL_USER) { | |
1da177e4 LT |
248 | state = ACL_GROUP; |
249 | break; | |
250 | } | |
251 | return -EINVAL; | |
252 | ||
253 | case ACL_GROUP: | |
254 | if (state != ACL_GROUP) | |
255 | return -EINVAL; | |
0d4d717f | 256 | if (!kgid_has_mapping(user_ns, pa->e_gid)) |
2f6f0654 | 257 | return -EINVAL; |
1da177e4 LT |
258 | needs_mask = 1; |
259 | break; | |
260 | ||
261 | case ACL_MASK: | |
262 | if (state != ACL_GROUP) | |
263 | return -EINVAL; | |
264 | state = ACL_OTHER; | |
265 | break; | |
266 | ||
267 | case ACL_OTHER: | |
268 | if (state == ACL_OTHER || | |
269 | (state == ACL_GROUP && !needs_mask)) { | |
270 | state = 0; | |
271 | break; | |
272 | } | |
273 | return -EINVAL; | |
274 | ||
275 | default: | |
276 | return -EINVAL; | |
277 | } | |
278 | } | |
279 | if (state == 0) | |
280 | return 0; | |
281 | return -EINVAL; | |
282 | } | |
0afaa120 | 283 | EXPORT_SYMBOL(posix_acl_valid); |
1da177e4 LT |
284 | |
285 | /* | |
286 | * Returns 0 if the acl can be exactly represented in the traditional | |
287 | * file mode permission bits, or else 1. Returns -E... on error. | |
288 | */ | |
289 | int | |
d6952123 | 290 | posix_acl_equiv_mode(const struct posix_acl *acl, umode_t *mode_p) |
1da177e4 LT |
291 | { |
292 | const struct posix_acl_entry *pa, *pe; | |
d6952123 | 293 | umode_t mode = 0; |
1da177e4 LT |
294 | int not_equiv = 0; |
295 | ||
50c6e282 CH |
296 | /* |
297 | * A null ACL can always be presented as mode bits. | |
298 | */ | |
299 | if (!acl) | |
300 | return 0; | |
301 | ||
1da177e4 LT |
302 | FOREACH_ACL_ENTRY(pa, acl, pe) { |
303 | switch (pa->e_tag) { | |
304 | case ACL_USER_OBJ: | |
305 | mode |= (pa->e_perm & S_IRWXO) << 6; | |
306 | break; | |
307 | case ACL_GROUP_OBJ: | |
308 | mode |= (pa->e_perm & S_IRWXO) << 3; | |
309 | break; | |
310 | case ACL_OTHER: | |
311 | mode |= pa->e_perm & S_IRWXO; | |
312 | break; | |
313 | case ACL_MASK: | |
314 | mode = (mode & ~S_IRWXG) | | |
315 | ((pa->e_perm & S_IRWXO) << 3); | |
316 | not_equiv = 1; | |
317 | break; | |
318 | case ACL_USER: | |
319 | case ACL_GROUP: | |
320 | not_equiv = 1; | |
321 | break; | |
322 | default: | |
323 | return -EINVAL; | |
324 | } | |
325 | } | |
326 | if (mode_p) | |
327 | *mode_p = (*mode_p & ~S_IRWXUGO) | mode; | |
328 | return not_equiv; | |
329 | } | |
0afaa120 | 330 | EXPORT_SYMBOL(posix_acl_equiv_mode); |
1da177e4 LT |
331 | |
332 | /* | |
333 | * Create an ACL representing the file mode permission bits of an inode. | |
334 | */ | |
335 | struct posix_acl * | |
3a5fba19 | 336 | posix_acl_from_mode(umode_t mode, gfp_t flags) |
1da177e4 LT |
337 | { |
338 | struct posix_acl *acl = posix_acl_alloc(3, flags); | |
339 | if (!acl) | |
340 | return ERR_PTR(-ENOMEM); | |
341 | ||
342 | acl->a_entries[0].e_tag = ACL_USER_OBJ; | |
1da177e4 LT |
343 | acl->a_entries[0].e_perm = (mode & S_IRWXU) >> 6; |
344 | ||
345 | acl->a_entries[1].e_tag = ACL_GROUP_OBJ; | |
1da177e4 LT |
346 | acl->a_entries[1].e_perm = (mode & S_IRWXG) >> 3; |
347 | ||
348 | acl->a_entries[2].e_tag = ACL_OTHER; | |
1da177e4 LT |
349 | acl->a_entries[2].e_perm = (mode & S_IRWXO); |
350 | return acl; | |
351 | } | |
0afaa120 | 352 | EXPORT_SYMBOL(posix_acl_from_mode); |
1da177e4 LT |
353 | |
354 | /* | |
355 | * Return 0 if current is granted want access to the inode | |
356 | * by the acl. Returns -E... otherwise. | |
357 | */ | |
358 | int | |
47291baa CB |
359 | posix_acl_permission(struct user_namespace *mnt_userns, struct inode *inode, |
360 | const struct posix_acl *acl, int want) | |
1da177e4 LT |
361 | { |
362 | const struct posix_acl_entry *pa, *pe, *mask_obj; | |
363 | int found = 0; | |
47291baa CB |
364 | kuid_t uid; |
365 | kgid_t gid; | |
1da177e4 | 366 | |
63d72b93 | 367 | want &= MAY_READ | MAY_WRITE | MAY_EXEC; |
d124b60a | 368 | |
1da177e4 LT |
369 | FOREACH_ACL_ENTRY(pa, acl, pe) { |
370 | switch(pa->e_tag) { | |
371 | case ACL_USER_OBJ: | |
372 | /* (May have been checked already) */ | |
47291baa CB |
373 | uid = i_uid_into_mnt(mnt_userns, inode); |
374 | if (uid_eq(uid, current_fsuid())) | |
1da177e4 LT |
375 | goto check_perm; |
376 | break; | |
377 | case ACL_USER: | |
47291baa CB |
378 | uid = kuid_into_mnt(mnt_userns, pa->e_uid); |
379 | if (uid_eq(uid, current_fsuid())) | |
1da177e4 LT |
380 | goto mask; |
381 | break; | |
382 | case ACL_GROUP_OBJ: | |
47291baa CB |
383 | gid = i_gid_into_mnt(mnt_userns, inode); |
384 | if (in_group_p(gid)) { | |
1da177e4 LT |
385 | found = 1; |
386 | if ((pa->e_perm & want) == want) | |
387 | goto mask; | |
388 | } | |
389 | break; | |
390 | case ACL_GROUP: | |
47291baa CB |
391 | gid = kgid_into_mnt(mnt_userns, pa->e_gid); |
392 | if (in_group_p(gid)) { | |
1da177e4 LT |
393 | found = 1; |
394 | if ((pa->e_perm & want) == want) | |
395 | goto mask; | |
396 | } | |
397 | break; | |
398 | case ACL_MASK: | |
399 | break; | |
400 | case ACL_OTHER: | |
401 | if (found) | |
402 | return -EACCES; | |
403 | else | |
404 | goto check_perm; | |
405 | default: | |
406 | return -EIO; | |
407 | } | |
408 | } | |
409 | return -EIO; | |
410 | ||
411 | mask: | |
412 | for (mask_obj = pa+1; mask_obj != pe; mask_obj++) { | |
413 | if (mask_obj->e_tag == ACL_MASK) { | |
414 | if ((pa->e_perm & mask_obj->e_perm & want) == want) | |
415 | return 0; | |
416 | return -EACCES; | |
417 | } | |
418 | } | |
419 | ||
420 | check_perm: | |
421 | if ((pa->e_perm & want) == want) | |
422 | return 0; | |
423 | return -EACCES; | |
424 | } | |
425 | ||
426 | /* | |
427 | * Modify acl when creating a new inode. The caller must ensure the acl is | |
428 | * only referenced once. | |
429 | * | |
430 | * mode_p initially must contain the mode parameter to the open() / creat() | |
431 | * system calls. All permissions that are not granted by the acl are removed. | |
432 | * The permissions in the acl are changed to reflect the mode_p parameter. | |
433 | */ | |
d3fb6120 | 434 | static int posix_acl_create_masq(struct posix_acl *acl, umode_t *mode_p) |
1da177e4 LT |
435 | { |
436 | struct posix_acl_entry *pa, *pe; | |
437 | struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL; | |
d3fb6120 | 438 | umode_t mode = *mode_p; |
1da177e4 LT |
439 | int not_equiv = 0; |
440 | ||
441 | /* assert(atomic_read(acl->a_refcount) == 1); */ | |
442 | ||
443 | FOREACH_ACL_ENTRY(pa, acl, pe) { | |
444 | switch(pa->e_tag) { | |
445 | case ACL_USER_OBJ: | |
446 | pa->e_perm &= (mode >> 6) | ~S_IRWXO; | |
447 | mode &= (pa->e_perm << 6) | ~S_IRWXU; | |
448 | break; | |
449 | ||
450 | case ACL_USER: | |
451 | case ACL_GROUP: | |
452 | not_equiv = 1; | |
453 | break; | |
454 | ||
455 | case ACL_GROUP_OBJ: | |
456 | group_obj = pa; | |
457 | break; | |
458 | ||
459 | case ACL_OTHER: | |
460 | pa->e_perm &= mode | ~S_IRWXO; | |
461 | mode &= pa->e_perm | ~S_IRWXO; | |
462 | break; | |
463 | ||
464 | case ACL_MASK: | |
465 | mask_obj = pa; | |
466 | not_equiv = 1; | |
467 | break; | |
468 | ||
469 | default: | |
470 | return -EIO; | |
471 | } | |
472 | } | |
473 | ||
474 | if (mask_obj) { | |
475 | mask_obj->e_perm &= (mode >> 3) | ~S_IRWXO; | |
476 | mode &= (mask_obj->e_perm << 3) | ~S_IRWXG; | |
477 | } else { | |
478 | if (!group_obj) | |
479 | return -EIO; | |
480 | group_obj->e_perm &= (mode >> 3) | ~S_IRWXO; | |
481 | mode &= (group_obj->e_perm << 3) | ~S_IRWXG; | |
482 | } | |
483 | ||
484 | *mode_p = (*mode_p & ~S_IRWXUGO) | mode; | |
485 | return not_equiv; | |
486 | } | |
487 | ||
488 | /* | |
489 | * Modify the ACL for the chmod syscall. | |
490 | */ | |
5bf3258f | 491 | static int __posix_acl_chmod_masq(struct posix_acl *acl, umode_t mode) |
1da177e4 LT |
492 | { |
493 | struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL; | |
494 | struct posix_acl_entry *pa, *pe; | |
495 | ||
496 | /* assert(atomic_read(acl->a_refcount) == 1); */ | |
497 | ||
498 | FOREACH_ACL_ENTRY(pa, acl, pe) { | |
499 | switch(pa->e_tag) { | |
500 | case ACL_USER_OBJ: | |
501 | pa->e_perm = (mode & S_IRWXU) >> 6; | |
502 | break; | |
503 | ||
504 | case ACL_USER: | |
505 | case ACL_GROUP: | |
506 | break; | |
507 | ||
508 | case ACL_GROUP_OBJ: | |
509 | group_obj = pa; | |
510 | break; | |
511 | ||
512 | case ACL_MASK: | |
513 | mask_obj = pa; | |
514 | break; | |
515 | ||
516 | case ACL_OTHER: | |
517 | pa->e_perm = (mode & S_IRWXO); | |
518 | break; | |
519 | ||
520 | default: | |
521 | return -EIO; | |
522 | } | |
523 | } | |
524 | ||
525 | if (mask_obj) { | |
526 | mask_obj->e_perm = (mode & S_IRWXG) >> 3; | |
527 | } else { | |
528 | if (!group_obj) | |
529 | return -EIO; | |
530 | group_obj->e_perm = (mode & S_IRWXG) >> 3; | |
531 | } | |
532 | ||
533 | return 0; | |
534 | } | |
bc26ab5f | 535 | |
826cae2f | 536 | int |
37bc1539 | 537 | __posix_acl_create(struct posix_acl **acl, gfp_t gfp, umode_t *mode_p) |
826cae2f AV |
538 | { |
539 | struct posix_acl *clone = posix_acl_clone(*acl, gfp); | |
540 | int err = -ENOMEM; | |
541 | if (clone) { | |
542 | err = posix_acl_create_masq(clone, mode_p); | |
543 | if (err < 0) { | |
544 | posix_acl_release(clone); | |
545 | clone = NULL; | |
546 | } | |
547 | } | |
548 | posix_acl_release(*acl); | |
549 | *acl = clone; | |
550 | return err; | |
551 | } | |
37bc1539 | 552 | EXPORT_SYMBOL(__posix_acl_create); |
826cae2f | 553 | |
bc26ab5f | 554 | int |
5bf3258f | 555 | __posix_acl_chmod(struct posix_acl **acl, gfp_t gfp, umode_t mode) |
bc26ab5f AV |
556 | { |
557 | struct posix_acl *clone = posix_acl_clone(*acl, gfp); | |
558 | int err = -ENOMEM; | |
559 | if (clone) { | |
5bf3258f | 560 | err = __posix_acl_chmod_masq(clone, mode); |
bc26ab5f AV |
561 | if (err) { |
562 | posix_acl_release(clone); | |
563 | clone = NULL; | |
564 | } | |
565 | } | |
566 | posix_acl_release(*acl); | |
567 | *acl = clone; | |
568 | return err; | |
569 | } | |
5bf3258f CH |
570 | EXPORT_SYMBOL(__posix_acl_chmod); |
571 | ||
e65ce2a5 CB |
572 | /** |
573 | * posix_acl_chmod - chmod a posix acl | |
574 | * | |
575 | * @mnt_userns: user namespace of the mount @inode was found from | |
576 | * @inode: inode to check permissions on | |
577 | * @mode: the new mode of @inode | |
578 | * | |
579 | * If the inode has been found through an idmapped mount the user namespace of | |
580 | * the vfsmount must be passed through @mnt_userns. This function will then | |
581 | * take care to map the inode according to @mnt_userns before checking | |
582 | * permissions. On non-idmapped mounts or if permission checking is to be | |
583 | * performed on the raw inode simply passs init_user_ns. | |
584 | */ | |
5bf3258f | 585 | int |
e65ce2a5 CB |
586 | posix_acl_chmod(struct user_namespace *mnt_userns, struct inode *inode, |
587 | umode_t mode) | |
5bf3258f CH |
588 | { |
589 | struct posix_acl *acl; | |
590 | int ret = 0; | |
591 | ||
592 | if (!IS_POSIXACL(inode)) | |
593 | return 0; | |
594 | if (!inode->i_op->set_acl) | |
595 | return -EOPNOTSUPP; | |
596 | ||
597 | acl = get_acl(inode, ACL_TYPE_ACCESS); | |
789b663a TM |
598 | if (IS_ERR_OR_NULL(acl)) { |
599 | if (acl == ERR_PTR(-EOPNOTSUPP)) | |
600 | return 0; | |
5bf3258f | 601 | return PTR_ERR(acl); |
789b663a | 602 | } |
5bf3258f | 603 | |
37bc1539 | 604 | ret = __posix_acl_chmod(&acl, GFP_KERNEL, mode); |
5bf3258f CH |
605 | if (ret) |
606 | return ret; | |
549c7297 | 607 | ret = inode->i_op->set_acl(mnt_userns, inode, acl, ACL_TYPE_ACCESS); |
5bf3258f CH |
608 | posix_acl_release(acl); |
609 | return ret; | |
610 | } | |
bc26ab5f | 611 | EXPORT_SYMBOL(posix_acl_chmod); |
5c8ebd57 | 612 | |
37bc1539 CH |
613 | int |
614 | posix_acl_create(struct inode *dir, umode_t *mode, | |
615 | struct posix_acl **default_acl, struct posix_acl **acl) | |
616 | { | |
617 | struct posix_acl *p; | |
c0c3a718 | 618 | struct posix_acl *clone; |
37bc1539 CH |
619 | int ret; |
620 | ||
c0c3a718 DC |
621 | *acl = NULL; |
622 | *default_acl = NULL; | |
623 | ||
37bc1539 | 624 | if (S_ISLNK(*mode) || !IS_POSIXACL(dir)) |
c0c3a718 | 625 | return 0; |
37bc1539 CH |
626 | |
627 | p = get_acl(dir, ACL_TYPE_DEFAULT); | |
c0c3a718 DC |
628 | if (!p || p == ERR_PTR(-EOPNOTSUPP)) { |
629 | *mode &= ~current_umask(); | |
630 | return 0; | |
37bc1539 | 631 | } |
c0c3a718 DC |
632 | if (IS_ERR(p)) |
633 | return PTR_ERR(p); | |
37bc1539 | 634 | |
beaf226b | 635 | ret = -ENOMEM; |
c0c3a718 DC |
636 | clone = posix_acl_clone(p, GFP_NOFS); |
637 | if (!clone) | |
beaf226b | 638 | goto err_release; |
37bc1539 | 639 | |
c0c3a718 | 640 | ret = posix_acl_create_masq(clone, mode); |
fed0b588 | 641 | if (ret < 0) |
beaf226b | 642 | goto err_release_clone; |
37bc1539 | 643 | |
c0c3a718 DC |
644 | if (ret == 0) |
645 | posix_acl_release(clone); | |
646 | else | |
647 | *acl = clone; | |
37bc1539 | 648 | |
c0c3a718 | 649 | if (!S_ISDIR(*mode)) |
37bc1539 | 650 | posix_acl_release(p); |
c0c3a718 | 651 | else |
37bc1539 | 652 | *default_acl = p; |
37bc1539 | 653 | |
37bc1539 | 654 | return 0; |
fed0b588 | 655 | |
beaf226b | 656 | err_release_clone: |
c0c3a718 | 657 | posix_acl_release(clone); |
beaf226b | 658 | err_release: |
fed0b588 | 659 | posix_acl_release(p); |
beaf226b | 660 | return ret; |
37bc1539 CH |
661 | } |
662 | EXPORT_SYMBOL_GPL(posix_acl_create); | |
663 | ||
07393101 JK |
664 | /** |
665 | * posix_acl_update_mode - update mode in set_acl | |
e65ce2a5 CB |
666 | * @mnt_userns: user namespace of the mount @inode was found from |
667 | * @inode: target inode | |
668 | * @mode_p: mode (pointer) for update | |
669 | * @acl: acl pointer | |
07393101 JK |
670 | * |
671 | * Update the file mode when setting an ACL: compute the new file permission | |
672 | * bits based on the ACL. In addition, if the ACL is equivalent to the new | |
e39e773a | 673 | * file mode, set *@acl to NULL to indicate that no ACL should be set. |
07393101 | 674 | * |
e39e773a | 675 | * As with chmod, clear the setgid bit if the caller is not in the owning group |
07393101 JK |
676 | * or capable of CAP_FSETID (see inode_change_ok). |
677 | * | |
e65ce2a5 CB |
678 | * If the inode has been found through an idmapped mount the user namespace of |
679 | * the vfsmount must be passed through @mnt_userns. This function will then | |
680 | * take care to map the inode according to @mnt_userns before checking | |
681 | * permissions. On non-idmapped mounts or if permission checking is to be | |
682 | * performed on the raw inode simply passs init_user_ns. | |
683 | * | |
07393101 JK |
684 | * Called from set_acl inode operations. |
685 | */ | |
e65ce2a5 CB |
686 | int posix_acl_update_mode(struct user_namespace *mnt_userns, |
687 | struct inode *inode, umode_t *mode_p, | |
07393101 JK |
688 | struct posix_acl **acl) |
689 | { | |
690 | umode_t mode = inode->i_mode; | |
691 | int error; | |
692 | ||
693 | error = posix_acl_equiv_mode(*acl, &mode); | |
694 | if (error < 0) | |
695 | return error; | |
696 | if (error == 0) | |
697 | *acl = NULL; | |
e65ce2a5 CB |
698 | if (!in_group_p(i_gid_into_mnt(mnt_userns, inode)) && |
699 | !capable_wrt_inode_uidgid(mnt_userns, inode, CAP_FSETID)) | |
07393101 JK |
700 | mode &= ~S_ISGID; |
701 | *mode_p = mode; | |
702 | return 0; | |
703 | } | |
704 | EXPORT_SYMBOL(posix_acl_update_mode); | |
705 | ||
5c8ebd57 CH |
706 | /* |
707 | * Fix up the uids and gids in posix acl extended attributes in place. | |
708 | */ | |
709 | static void posix_acl_fix_xattr_userns( | |
710 | struct user_namespace *to, struct user_namespace *from, | |
e65ce2a5 CB |
711 | struct user_namespace *mnt_userns, |
712 | void *value, size_t size, bool from_user) | |
5c8ebd57 | 713 | { |
2211d5ba AG |
714 | struct posix_acl_xattr_header *header = value; |
715 | struct posix_acl_xattr_entry *entry = (void *)(header + 1), *end; | |
5c8ebd57 CH |
716 | int count; |
717 | kuid_t uid; | |
718 | kgid_t gid; | |
719 | ||
720 | if (!value) | |
721 | return; | |
2211d5ba | 722 | if (size < sizeof(struct posix_acl_xattr_header)) |
5c8ebd57 CH |
723 | return; |
724 | if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION)) | |
725 | return; | |
726 | ||
727 | count = posix_acl_xattr_count(size); | |
728 | if (count < 0) | |
729 | return; | |
730 | if (count == 0) | |
731 | return; | |
732 | ||
733 | for (end = entry + count; entry != end; entry++) { | |
734 | switch(le16_to_cpu(entry->e_tag)) { | |
735 | case ACL_USER: | |
736 | uid = make_kuid(from, le32_to_cpu(entry->e_id)); | |
e65ce2a5 CB |
737 | if (from_user) |
738 | uid = kuid_from_mnt(mnt_userns, uid); | |
739 | else | |
740 | uid = kuid_into_mnt(mnt_userns, uid); | |
5c8ebd57 CH |
741 | entry->e_id = cpu_to_le32(from_kuid(to, uid)); |
742 | break; | |
743 | case ACL_GROUP: | |
744 | gid = make_kgid(from, le32_to_cpu(entry->e_id)); | |
e65ce2a5 CB |
745 | if (from_user) |
746 | gid = kgid_from_mnt(mnt_userns, gid); | |
747 | else | |
748 | gid = kgid_into_mnt(mnt_userns, gid); | |
5c8ebd57 CH |
749 | entry->e_id = cpu_to_le32(from_kgid(to, gid)); |
750 | break; | |
751 | default: | |
752 | break; | |
753 | } | |
754 | } | |
755 | } | |
756 | ||
e65ce2a5 CB |
757 | void posix_acl_fix_xattr_from_user(struct user_namespace *mnt_userns, |
758 | void *value, size_t size) | |
5c8ebd57 CH |
759 | { |
760 | struct user_namespace *user_ns = current_user_ns(); | |
e65ce2a5 | 761 | if ((user_ns == &init_user_ns) && (mnt_userns == &init_user_ns)) |
5c8ebd57 | 762 | return; |
e65ce2a5 CB |
763 | posix_acl_fix_xattr_userns(&init_user_ns, user_ns, mnt_userns, value, |
764 | size, true); | |
5c8ebd57 CH |
765 | } |
766 | ||
e65ce2a5 CB |
767 | void posix_acl_fix_xattr_to_user(struct user_namespace *mnt_userns, |
768 | void *value, size_t size) | |
5c8ebd57 CH |
769 | { |
770 | struct user_namespace *user_ns = current_user_ns(); | |
e65ce2a5 | 771 | if ((user_ns == &init_user_ns) && (mnt_userns == &init_user_ns)) |
5c8ebd57 | 772 | return; |
e65ce2a5 CB |
773 | posix_acl_fix_xattr_userns(user_ns, &init_user_ns, mnt_userns, value, |
774 | size, false); | |
5c8ebd57 CH |
775 | } |
776 | ||
777 | /* | |
778 | * Convert from extended attribute to in-memory representation. | |
779 | */ | |
780 | struct posix_acl * | |
781 | posix_acl_from_xattr(struct user_namespace *user_ns, | |
782 | const void *value, size_t size) | |
783 | { | |
2211d5ba AG |
784 | const struct posix_acl_xattr_header *header = value; |
785 | const struct posix_acl_xattr_entry *entry = (const void *)(header + 1), *end; | |
5c8ebd57 CH |
786 | int count; |
787 | struct posix_acl *acl; | |
788 | struct posix_acl_entry *acl_e; | |
789 | ||
790 | if (!value) | |
791 | return NULL; | |
2211d5ba | 792 | if (size < sizeof(struct posix_acl_xattr_header)) |
5c8ebd57 CH |
793 | return ERR_PTR(-EINVAL); |
794 | if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION)) | |
795 | return ERR_PTR(-EOPNOTSUPP); | |
796 | ||
797 | count = posix_acl_xattr_count(size); | |
798 | if (count < 0) | |
799 | return ERR_PTR(-EINVAL); | |
800 | if (count == 0) | |
801 | return NULL; | |
802 | ||
803 | acl = posix_acl_alloc(count, GFP_NOFS); | |
804 | if (!acl) | |
805 | return ERR_PTR(-ENOMEM); | |
806 | acl_e = acl->a_entries; | |
807 | ||
808 | for (end = entry + count; entry != end; acl_e++, entry++) { | |
809 | acl_e->e_tag = le16_to_cpu(entry->e_tag); | |
810 | acl_e->e_perm = le16_to_cpu(entry->e_perm); | |
811 | ||
812 | switch(acl_e->e_tag) { | |
813 | case ACL_USER_OBJ: | |
814 | case ACL_GROUP_OBJ: | |
815 | case ACL_MASK: | |
816 | case ACL_OTHER: | |
817 | break; | |
818 | ||
819 | case ACL_USER: | |
820 | acl_e->e_uid = | |
821 | make_kuid(user_ns, | |
822 | le32_to_cpu(entry->e_id)); | |
823 | if (!uid_valid(acl_e->e_uid)) | |
824 | goto fail; | |
825 | break; | |
826 | case ACL_GROUP: | |
827 | acl_e->e_gid = | |
828 | make_kgid(user_ns, | |
829 | le32_to_cpu(entry->e_id)); | |
830 | if (!gid_valid(acl_e->e_gid)) | |
831 | goto fail; | |
832 | break; | |
833 | ||
834 | default: | |
835 | goto fail; | |
836 | } | |
837 | } | |
838 | return acl; | |
839 | ||
840 | fail: | |
841 | posix_acl_release(acl); | |
842 | return ERR_PTR(-EINVAL); | |
843 | } | |
844 | EXPORT_SYMBOL (posix_acl_from_xattr); | |
845 | ||
846 | /* | |
847 | * Convert from in-memory to extended attribute representation. | |
848 | */ | |
849 | int | |
850 | posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl, | |
851 | void *buffer, size_t size) | |
852 | { | |
2211d5ba AG |
853 | struct posix_acl_xattr_header *ext_acl = buffer; |
854 | struct posix_acl_xattr_entry *ext_entry; | |
5c8ebd57 CH |
855 | int real_size, n; |
856 | ||
857 | real_size = posix_acl_xattr_size(acl->a_count); | |
858 | if (!buffer) | |
859 | return real_size; | |
860 | if (real_size > size) | |
861 | return -ERANGE; | |
47ba9734 | 862 | |
2211d5ba | 863 | ext_entry = (void *)(ext_acl + 1); |
5c8ebd57 CH |
864 | ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION); |
865 | ||
866 | for (n=0; n < acl->a_count; n++, ext_entry++) { | |
867 | const struct posix_acl_entry *acl_e = &acl->a_entries[n]; | |
868 | ext_entry->e_tag = cpu_to_le16(acl_e->e_tag); | |
869 | ext_entry->e_perm = cpu_to_le16(acl_e->e_perm); | |
870 | switch(acl_e->e_tag) { | |
871 | case ACL_USER: | |
872 | ext_entry->e_id = | |
873 | cpu_to_le32(from_kuid(user_ns, acl_e->e_uid)); | |
874 | break; | |
875 | case ACL_GROUP: | |
876 | ext_entry->e_id = | |
877 | cpu_to_le32(from_kgid(user_ns, acl_e->e_gid)); | |
878 | break; | |
879 | default: | |
880 | ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID); | |
881 | break; | |
882 | } | |
883 | } | |
884 | return real_size; | |
885 | } | |
886 | EXPORT_SYMBOL (posix_acl_to_xattr); | |
2aeccbe9 CH |
887 | |
888 | static int | |
d9a82a04 | 889 | posix_acl_xattr_get(const struct xattr_handler *handler, |
b296821a AV |
890 | struct dentry *unused, struct inode *inode, |
891 | const char *name, void *value, size_t size) | |
2aeccbe9 CH |
892 | { |
893 | struct posix_acl *acl; | |
894 | int error; | |
895 | ||
b296821a | 896 | if (!IS_POSIXACL(inode)) |
2aeccbe9 | 897 | return -EOPNOTSUPP; |
b296821a | 898 | if (S_ISLNK(inode->i_mode)) |
2aeccbe9 CH |
899 | return -EOPNOTSUPP; |
900 | ||
b296821a | 901 | acl = get_acl(inode, handler->flags); |
2aeccbe9 CH |
902 | if (IS_ERR(acl)) |
903 | return PTR_ERR(acl); | |
904 | if (acl == NULL) | |
905 | return -ENODATA; | |
906 | ||
907 | error = posix_acl_to_xattr(&init_user_ns, acl, value, size); | |
908 | posix_acl_release(acl); | |
909 | ||
910 | return error; | |
911 | } | |
912 | ||
485e71e8 | 913 | int |
e65ce2a5 CB |
914 | set_posix_acl(struct user_namespace *mnt_userns, struct inode *inode, |
915 | int type, struct posix_acl *acl) | |
2aeccbe9 | 916 | { |
2aeccbe9 CH |
917 | if (!IS_POSIXACL(inode)) |
918 | return -EOPNOTSUPP; | |
919 | if (!inode->i_op->set_acl) | |
920 | return -EOPNOTSUPP; | |
921 | ||
485e71e8 AG |
922 | if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode)) |
923 | return acl ? -EACCES : 0; | |
e65ce2a5 | 924 | if (!inode_owner_or_capable(mnt_userns, inode)) |
2aeccbe9 CH |
925 | return -EPERM; |
926 | ||
485e71e8 | 927 | if (acl) { |
a867d734 | 928 | int ret = posix_acl_valid(inode->i_sb->s_user_ns, acl); |
485e71e8 AG |
929 | if (ret) |
930 | return ret; | |
931 | } | |
549c7297 | 932 | return inode->i_op->set_acl(mnt_userns, inode, acl, type); |
485e71e8 AG |
933 | } |
934 | EXPORT_SYMBOL(set_posix_acl); | |
935 | ||
936 | static int | |
937 | posix_acl_xattr_set(const struct xattr_handler *handler, | |
e65ce2a5 CB |
938 | struct user_namespace *mnt_userns, |
939 | struct dentry *unused, struct inode *inode, | |
940 | const char *name, const void *value, size_t size, | |
941 | int flags) | |
485e71e8 AG |
942 | { |
943 | struct posix_acl *acl = NULL; | |
944 | int ret; | |
945 | ||
2aeccbe9 CH |
946 | if (value) { |
947 | acl = posix_acl_from_xattr(&init_user_ns, value, size); | |
948 | if (IS_ERR(acl)) | |
949 | return PTR_ERR(acl); | |
2aeccbe9 | 950 | } |
e65ce2a5 | 951 | ret = set_posix_acl(mnt_userns, inode, handler->flags, acl); |
2aeccbe9 CH |
952 | posix_acl_release(acl); |
953 | return ret; | |
954 | } | |
955 | ||
764a5c6b AG |
956 | static bool |
957 | posix_acl_xattr_list(struct dentry *dentry) | |
2aeccbe9 | 958 | { |
764a5c6b | 959 | return IS_POSIXACL(d_backing_inode(dentry)); |
2aeccbe9 CH |
960 | } |
961 | ||
962 | const struct xattr_handler posix_acl_access_xattr_handler = { | |
98e9cb57 | 963 | .name = XATTR_NAME_POSIX_ACL_ACCESS, |
2aeccbe9 CH |
964 | .flags = ACL_TYPE_ACCESS, |
965 | .list = posix_acl_xattr_list, | |
966 | .get = posix_acl_xattr_get, | |
967 | .set = posix_acl_xattr_set, | |
968 | }; | |
969 | EXPORT_SYMBOL_GPL(posix_acl_access_xattr_handler); | |
970 | ||
971 | const struct xattr_handler posix_acl_default_xattr_handler = { | |
98e9cb57 | 972 | .name = XATTR_NAME_POSIX_ACL_DEFAULT, |
2aeccbe9 CH |
973 | .flags = ACL_TYPE_DEFAULT, |
974 | .list = posix_acl_xattr_list, | |
975 | .get = posix_acl_xattr_get, | |
976 | .set = posix_acl_xattr_set, | |
977 | }; | |
978 | EXPORT_SYMBOL_GPL(posix_acl_default_xattr_handler); | |
feda821e | 979 | |
549c7297 CB |
980 | int simple_set_acl(struct user_namespace *mnt_userns, struct inode *inode, |
981 | struct posix_acl *acl, int type) | |
feda821e CH |
982 | { |
983 | int error; | |
984 | ||
985 | if (type == ACL_TYPE_ACCESS) { | |
549c7297 | 986 | error = posix_acl_update_mode(mnt_userns, inode, |
497de07d GZ |
987 | &inode->i_mode, &acl); |
988 | if (error) | |
989 | return error; | |
feda821e CH |
990 | } |
991 | ||
078cd827 | 992 | inode->i_ctime = current_time(inode); |
feda821e CH |
993 | set_cached_acl(inode, type, acl); |
994 | return 0; | |
995 | } | |
996 | ||
997 | int simple_acl_create(struct inode *dir, struct inode *inode) | |
998 | { | |
999 | struct posix_acl *default_acl, *acl; | |
1000 | int error; | |
1001 | ||
1002 | error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl); | |
1003 | if (error) | |
1004 | return error; | |
1005 | ||
1006 | set_cached_acl(inode, ACL_TYPE_DEFAULT, default_acl); | |
1007 | set_cached_acl(inode, ACL_TYPE_ACCESS, acl); | |
1008 | ||
1009 | if (default_acl) | |
1010 | posix_acl_release(default_acl); | |
1011 | if (acl) | |
1012 | posix_acl_release(acl); | |
1013 | return 0; | |
1014 | } |