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> |
1da177e4 | 27 | |
04c57f45 | 28 | static struct posix_acl **acl_by_type(struct inode *inode, int type) |
0afaa120 AM |
29 | { |
30 | switch (type) { | |
31 | case ACL_TYPE_ACCESS: | |
32 | return &inode->i_acl; | |
33 | case ACL_TYPE_DEFAULT: | |
34 | return &inode->i_default_acl; | |
35 | default: | |
36 | BUG(); | |
37 | } | |
38 | } | |
0afaa120 AM |
39 | |
40 | struct posix_acl *get_cached_acl(struct inode *inode, int type) | |
41 | { | |
42 | struct posix_acl **p = acl_by_type(inode, type); | |
b8a7a3a6 AG |
43 | struct posix_acl *acl; |
44 | ||
45 | for (;;) { | |
46 | rcu_read_lock(); | |
47 | acl = rcu_dereference(*p); | |
48 | if (!acl || is_uncached_acl(acl) || | |
66717260 | 49 | refcount_inc_not_zero(&acl->a_refcount)) |
b8a7a3a6 AG |
50 | break; |
51 | rcu_read_unlock(); | |
52 | cpu_relax(); | |
0afaa120 | 53 | } |
b8a7a3a6 | 54 | rcu_read_unlock(); |
0afaa120 AM |
55 | return acl; |
56 | } | |
57 | EXPORT_SYMBOL(get_cached_acl); | |
58 | ||
59 | struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type) | |
60 | { | |
332f606b MS |
61 | struct posix_acl *acl = rcu_dereference(*acl_by_type(inode, type)); |
62 | ||
63 | if (acl == ACL_DONT_CACHE) { | |
64 | struct posix_acl *ret; | |
65 | ||
66 | ret = inode->i_op->get_acl(inode, type, LOOKUP_RCU); | |
67 | if (!IS_ERR(ret)) | |
68 | acl = ret; | |
69 | } | |
70 | ||
71 | return acl; | |
0afaa120 AM |
72 | } |
73 | EXPORT_SYMBOL(get_cached_acl_rcu); | |
74 | ||
75 | void set_cached_acl(struct inode *inode, int type, struct posix_acl *acl) | |
76 | { | |
77 | struct posix_acl **p = acl_by_type(inode, type); | |
78 | struct posix_acl *old; | |
b8a7a3a6 AG |
79 | |
80 | old = xchg(p, posix_acl_dup(acl)); | |
81 | if (!is_uncached_acl(old)) | |
0afaa120 AM |
82 | posix_acl_release(old); |
83 | } | |
84 | EXPORT_SYMBOL(set_cached_acl); | |
85 | ||
b8a7a3a6 | 86 | static void __forget_cached_acl(struct posix_acl **p) |
0afaa120 | 87 | { |
0afaa120 | 88 | struct posix_acl *old; |
b8a7a3a6 AG |
89 | |
90 | old = xchg(p, ACL_NOT_CACHED); | |
91 | if (!is_uncached_acl(old)) | |
0afaa120 AM |
92 | posix_acl_release(old); |
93 | } | |
b8a7a3a6 AG |
94 | |
95 | void forget_cached_acl(struct inode *inode, int type) | |
96 | { | |
97 | __forget_cached_acl(acl_by_type(inode, type)); | |
98 | } | |
0afaa120 AM |
99 | EXPORT_SYMBOL(forget_cached_acl); |
100 | ||
101 | void forget_all_cached_acls(struct inode *inode) | |
102 | { | |
b8a7a3a6 AG |
103 | __forget_cached_acl(&inode->i_acl); |
104 | __forget_cached_acl(&inode->i_default_acl); | |
0afaa120 AM |
105 | } |
106 | EXPORT_SYMBOL(forget_all_cached_acls); | |
1da177e4 | 107 | |
2982baa2 CH |
108 | struct posix_acl *get_acl(struct inode *inode, int type) |
109 | { | |
b8a7a3a6 AG |
110 | void *sentinel; |
111 | struct posix_acl **p; | |
2982baa2 CH |
112 | struct posix_acl *acl; |
113 | ||
b8a7a3a6 AG |
114 | /* |
115 | * The sentinel is used to detect when another operation like | |
116 | * set_cached_acl() or forget_cached_acl() races with get_acl(). | |
117 | * It is guaranteed that is_uncached_acl(sentinel) is true. | |
118 | */ | |
119 | ||
2982baa2 | 120 | acl = get_cached_acl(inode, type); |
b8a7a3a6 | 121 | if (!is_uncached_acl(acl)) |
2982baa2 CH |
122 | return acl; |
123 | ||
124 | if (!IS_POSIXACL(inode)) | |
125 | return NULL; | |
126 | ||
b8a7a3a6 AG |
127 | sentinel = uncached_acl_sentinel(current); |
128 | p = acl_by_type(inode, type); | |
129 | ||
130 | /* | |
131 | * If the ACL isn't being read yet, set our sentinel. Otherwise, the | |
132 | * current value of the ACL will not be ACL_NOT_CACHED and so our own | |
133 | * sentinel will not be set; another task will update the cache. We | |
134 | * could wait for that other task to complete its job, but it's easier | |
135 | * to just call ->get_acl to fetch the ACL ourself. (This is going to | |
136 | * be an unlikely race.) | |
137 | */ | |
d1cef29a | 138 | cmpxchg(p, ACL_NOT_CACHED, sentinel); |
b8a7a3a6 | 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: | |
44720713 | 378 | uid = mapped_kuid_fs(mnt_userns, |
bd303368 CB |
379 | i_user_ns(inode), |
380 | pa->e_uid); | |
47291baa | 381 | if (uid_eq(uid, current_fsuid())) |
1da177e4 LT |
382 | goto mask; |
383 | break; | |
384 | case ACL_GROUP_OBJ: | |
47291baa CB |
385 | gid = i_gid_into_mnt(mnt_userns, inode); |
386 | if (in_group_p(gid)) { | |
1da177e4 LT |
387 | found = 1; |
388 | if ((pa->e_perm & want) == want) | |
389 | goto mask; | |
390 | } | |
391 | break; | |
392 | case ACL_GROUP: | |
44720713 | 393 | gid = mapped_kgid_fs(mnt_userns, |
bd303368 CB |
394 | i_user_ns(inode), |
395 | pa->e_gid); | |
47291baa | 396 | if (in_group_p(gid)) { |
1da177e4 LT |
397 | found = 1; |
398 | if ((pa->e_perm & want) == want) | |
399 | goto mask; | |
400 | } | |
401 | break; | |
402 | case ACL_MASK: | |
403 | break; | |
404 | case ACL_OTHER: | |
405 | if (found) | |
406 | return -EACCES; | |
407 | else | |
408 | goto check_perm; | |
409 | default: | |
410 | return -EIO; | |
411 | } | |
412 | } | |
413 | return -EIO; | |
414 | ||
415 | mask: | |
416 | for (mask_obj = pa+1; mask_obj != pe; mask_obj++) { | |
417 | if (mask_obj->e_tag == ACL_MASK) { | |
418 | if ((pa->e_perm & mask_obj->e_perm & want) == want) | |
419 | return 0; | |
420 | return -EACCES; | |
421 | } | |
422 | } | |
423 | ||
424 | check_perm: | |
425 | if ((pa->e_perm & want) == want) | |
426 | return 0; | |
427 | return -EACCES; | |
428 | } | |
429 | ||
430 | /* | |
431 | * Modify acl when creating a new inode. The caller must ensure the acl is | |
432 | * only referenced once. | |
433 | * | |
434 | * mode_p initially must contain the mode parameter to the open() / creat() | |
435 | * system calls. All permissions that are not granted by the acl are removed. | |
436 | * The permissions in the acl are changed to reflect the mode_p parameter. | |
437 | */ | |
d3fb6120 | 438 | static int posix_acl_create_masq(struct posix_acl *acl, umode_t *mode_p) |
1da177e4 LT |
439 | { |
440 | struct posix_acl_entry *pa, *pe; | |
441 | struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL; | |
d3fb6120 | 442 | umode_t mode = *mode_p; |
1da177e4 LT |
443 | int not_equiv = 0; |
444 | ||
445 | /* assert(atomic_read(acl->a_refcount) == 1); */ | |
446 | ||
447 | FOREACH_ACL_ENTRY(pa, acl, pe) { | |
448 | switch(pa->e_tag) { | |
449 | case ACL_USER_OBJ: | |
450 | pa->e_perm &= (mode >> 6) | ~S_IRWXO; | |
451 | mode &= (pa->e_perm << 6) | ~S_IRWXU; | |
452 | break; | |
453 | ||
454 | case ACL_USER: | |
455 | case ACL_GROUP: | |
456 | not_equiv = 1; | |
457 | break; | |
458 | ||
459 | case ACL_GROUP_OBJ: | |
460 | group_obj = pa; | |
461 | break; | |
462 | ||
463 | case ACL_OTHER: | |
464 | pa->e_perm &= mode | ~S_IRWXO; | |
465 | mode &= pa->e_perm | ~S_IRWXO; | |
466 | break; | |
467 | ||
468 | case ACL_MASK: | |
469 | mask_obj = pa; | |
470 | not_equiv = 1; | |
471 | break; | |
472 | ||
473 | default: | |
474 | return -EIO; | |
475 | } | |
476 | } | |
477 | ||
478 | if (mask_obj) { | |
479 | mask_obj->e_perm &= (mode >> 3) | ~S_IRWXO; | |
480 | mode &= (mask_obj->e_perm << 3) | ~S_IRWXG; | |
481 | } else { | |
482 | if (!group_obj) | |
483 | return -EIO; | |
484 | group_obj->e_perm &= (mode >> 3) | ~S_IRWXO; | |
485 | mode &= (group_obj->e_perm << 3) | ~S_IRWXG; | |
486 | } | |
487 | ||
488 | *mode_p = (*mode_p & ~S_IRWXUGO) | mode; | |
489 | return not_equiv; | |
490 | } | |
491 | ||
492 | /* | |
493 | * Modify the ACL for the chmod syscall. | |
494 | */ | |
5bf3258f | 495 | static int __posix_acl_chmod_masq(struct posix_acl *acl, umode_t mode) |
1da177e4 LT |
496 | { |
497 | struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL; | |
498 | struct posix_acl_entry *pa, *pe; | |
499 | ||
500 | /* assert(atomic_read(acl->a_refcount) == 1); */ | |
501 | ||
502 | FOREACH_ACL_ENTRY(pa, acl, pe) { | |
503 | switch(pa->e_tag) { | |
504 | case ACL_USER_OBJ: | |
505 | pa->e_perm = (mode & S_IRWXU) >> 6; | |
506 | break; | |
507 | ||
508 | case ACL_USER: | |
509 | case ACL_GROUP: | |
510 | break; | |
511 | ||
512 | case ACL_GROUP_OBJ: | |
513 | group_obj = pa; | |
514 | break; | |
515 | ||
516 | case ACL_MASK: | |
517 | mask_obj = pa; | |
518 | break; | |
519 | ||
520 | case ACL_OTHER: | |
521 | pa->e_perm = (mode & S_IRWXO); | |
522 | break; | |
523 | ||
524 | default: | |
525 | return -EIO; | |
526 | } | |
527 | } | |
528 | ||
529 | if (mask_obj) { | |
530 | mask_obj->e_perm = (mode & S_IRWXG) >> 3; | |
531 | } else { | |
532 | if (!group_obj) | |
533 | return -EIO; | |
534 | group_obj->e_perm = (mode & S_IRWXG) >> 3; | |
535 | } | |
536 | ||
537 | return 0; | |
538 | } | |
bc26ab5f | 539 | |
826cae2f | 540 | int |
37bc1539 | 541 | __posix_acl_create(struct posix_acl **acl, gfp_t gfp, umode_t *mode_p) |
826cae2f AV |
542 | { |
543 | struct posix_acl *clone = posix_acl_clone(*acl, gfp); | |
544 | int err = -ENOMEM; | |
545 | if (clone) { | |
546 | err = posix_acl_create_masq(clone, mode_p); | |
547 | if (err < 0) { | |
548 | posix_acl_release(clone); | |
549 | clone = NULL; | |
550 | } | |
551 | } | |
552 | posix_acl_release(*acl); | |
553 | *acl = clone; | |
554 | return err; | |
555 | } | |
37bc1539 | 556 | EXPORT_SYMBOL(__posix_acl_create); |
826cae2f | 557 | |
bc26ab5f | 558 | int |
5bf3258f | 559 | __posix_acl_chmod(struct posix_acl **acl, gfp_t gfp, umode_t mode) |
bc26ab5f AV |
560 | { |
561 | struct posix_acl *clone = posix_acl_clone(*acl, gfp); | |
562 | int err = -ENOMEM; | |
563 | if (clone) { | |
5bf3258f | 564 | err = __posix_acl_chmod_masq(clone, mode); |
bc26ab5f AV |
565 | if (err) { |
566 | posix_acl_release(clone); | |
567 | clone = NULL; | |
568 | } | |
569 | } | |
570 | posix_acl_release(*acl); | |
571 | *acl = clone; | |
572 | return err; | |
573 | } | |
5bf3258f CH |
574 | EXPORT_SYMBOL(__posix_acl_chmod); |
575 | ||
e65ce2a5 CB |
576 | /** |
577 | * posix_acl_chmod - chmod a posix acl | |
578 | * | |
579 | * @mnt_userns: user namespace of the mount @inode was found from | |
580 | * @inode: inode to check permissions on | |
581 | * @mode: the new mode of @inode | |
582 | * | |
583 | * If the inode has been found through an idmapped mount the user namespace of | |
584 | * the vfsmount must be passed through @mnt_userns. This function will then | |
585 | * take care to map the inode according to @mnt_userns before checking | |
586 | * permissions. On non-idmapped mounts or if permission checking is to be | |
587 | * performed on the raw inode simply passs init_user_ns. | |
588 | */ | |
5bf3258f | 589 | int |
e65ce2a5 CB |
590 | posix_acl_chmod(struct user_namespace *mnt_userns, struct inode *inode, |
591 | umode_t mode) | |
5bf3258f CH |
592 | { |
593 | struct posix_acl *acl; | |
594 | int ret = 0; | |
595 | ||
596 | if (!IS_POSIXACL(inode)) | |
597 | return 0; | |
598 | if (!inode->i_op->set_acl) | |
599 | return -EOPNOTSUPP; | |
600 | ||
601 | acl = get_acl(inode, ACL_TYPE_ACCESS); | |
789b663a TM |
602 | if (IS_ERR_OR_NULL(acl)) { |
603 | if (acl == ERR_PTR(-EOPNOTSUPP)) | |
604 | return 0; | |
5bf3258f | 605 | return PTR_ERR(acl); |
789b663a | 606 | } |
5bf3258f | 607 | |
37bc1539 | 608 | ret = __posix_acl_chmod(&acl, GFP_KERNEL, mode); |
5bf3258f CH |
609 | if (ret) |
610 | return ret; | |
549c7297 | 611 | ret = inode->i_op->set_acl(mnt_userns, inode, acl, ACL_TYPE_ACCESS); |
5bf3258f CH |
612 | posix_acl_release(acl); |
613 | return ret; | |
614 | } | |
bc26ab5f | 615 | EXPORT_SYMBOL(posix_acl_chmod); |
5c8ebd57 | 616 | |
37bc1539 CH |
617 | int |
618 | posix_acl_create(struct inode *dir, umode_t *mode, | |
619 | struct posix_acl **default_acl, struct posix_acl **acl) | |
620 | { | |
621 | struct posix_acl *p; | |
c0c3a718 | 622 | struct posix_acl *clone; |
37bc1539 CH |
623 | int ret; |
624 | ||
c0c3a718 DC |
625 | *acl = NULL; |
626 | *default_acl = NULL; | |
627 | ||
37bc1539 | 628 | if (S_ISLNK(*mode) || !IS_POSIXACL(dir)) |
c0c3a718 | 629 | return 0; |
37bc1539 CH |
630 | |
631 | p = get_acl(dir, ACL_TYPE_DEFAULT); | |
c0c3a718 DC |
632 | if (!p || p == ERR_PTR(-EOPNOTSUPP)) { |
633 | *mode &= ~current_umask(); | |
634 | return 0; | |
37bc1539 | 635 | } |
c0c3a718 DC |
636 | if (IS_ERR(p)) |
637 | return PTR_ERR(p); | |
37bc1539 | 638 | |
beaf226b | 639 | ret = -ENOMEM; |
c0c3a718 DC |
640 | clone = posix_acl_clone(p, GFP_NOFS); |
641 | if (!clone) | |
beaf226b | 642 | goto err_release; |
37bc1539 | 643 | |
c0c3a718 | 644 | ret = posix_acl_create_masq(clone, mode); |
fed0b588 | 645 | if (ret < 0) |
beaf226b | 646 | goto err_release_clone; |
37bc1539 | 647 | |
c0c3a718 DC |
648 | if (ret == 0) |
649 | posix_acl_release(clone); | |
650 | else | |
651 | *acl = clone; | |
37bc1539 | 652 | |
c0c3a718 | 653 | if (!S_ISDIR(*mode)) |
37bc1539 | 654 | posix_acl_release(p); |
c0c3a718 | 655 | else |
37bc1539 | 656 | *default_acl = p; |
37bc1539 | 657 | |
37bc1539 | 658 | return 0; |
fed0b588 | 659 | |
beaf226b | 660 | err_release_clone: |
c0c3a718 | 661 | posix_acl_release(clone); |
beaf226b | 662 | err_release: |
fed0b588 | 663 | posix_acl_release(p); |
beaf226b | 664 | return ret; |
37bc1539 CH |
665 | } |
666 | EXPORT_SYMBOL_GPL(posix_acl_create); | |
667 | ||
07393101 JK |
668 | /** |
669 | * posix_acl_update_mode - update mode in set_acl | |
e65ce2a5 CB |
670 | * @mnt_userns: user namespace of the mount @inode was found from |
671 | * @inode: target inode | |
672 | * @mode_p: mode (pointer) for update | |
673 | * @acl: acl pointer | |
07393101 JK |
674 | * |
675 | * Update the file mode when setting an ACL: compute the new file permission | |
676 | * bits based on the ACL. In addition, if the ACL is equivalent to the new | |
e39e773a | 677 | * file mode, set *@acl to NULL to indicate that no ACL should be set. |
07393101 | 678 | * |
e39e773a | 679 | * As with chmod, clear the setgid bit if the caller is not in the owning group |
07393101 JK |
680 | * or capable of CAP_FSETID (see inode_change_ok). |
681 | * | |
e65ce2a5 CB |
682 | * If the inode has been found through an idmapped mount the user namespace of |
683 | * the vfsmount must be passed through @mnt_userns. This function will then | |
684 | * take care to map the inode according to @mnt_userns before checking | |
685 | * permissions. On non-idmapped mounts or if permission checking is to be | |
686 | * performed on the raw inode simply passs init_user_ns. | |
687 | * | |
07393101 JK |
688 | * Called from set_acl inode operations. |
689 | */ | |
e65ce2a5 CB |
690 | int posix_acl_update_mode(struct user_namespace *mnt_userns, |
691 | struct inode *inode, umode_t *mode_p, | |
07393101 JK |
692 | struct posix_acl **acl) |
693 | { | |
694 | umode_t mode = inode->i_mode; | |
695 | int error; | |
696 | ||
697 | error = posix_acl_equiv_mode(*acl, &mode); | |
698 | if (error < 0) | |
699 | return error; | |
700 | if (error == 0) | |
701 | *acl = NULL; | |
e65ce2a5 CB |
702 | if (!in_group_p(i_gid_into_mnt(mnt_userns, inode)) && |
703 | !capable_wrt_inode_uidgid(mnt_userns, inode, CAP_FSETID)) | |
07393101 JK |
704 | mode &= ~S_ISGID; |
705 | *mode_p = mode; | |
706 | return 0; | |
707 | } | |
708 | EXPORT_SYMBOL(posix_acl_update_mode); | |
709 | ||
5c8ebd57 CH |
710 | /* |
711 | * Fix up the uids and gids in posix acl extended attributes in place. | |
712 | */ | |
713 | static void posix_acl_fix_xattr_userns( | |
714 | struct user_namespace *to, struct user_namespace *from, | |
e65ce2a5 CB |
715 | struct user_namespace *mnt_userns, |
716 | void *value, size_t size, bool from_user) | |
5c8ebd57 | 717 | { |
2211d5ba AG |
718 | struct posix_acl_xattr_header *header = value; |
719 | struct posix_acl_xattr_entry *entry = (void *)(header + 1), *end; | |
5c8ebd57 CH |
720 | int count; |
721 | kuid_t uid; | |
722 | kgid_t gid; | |
723 | ||
724 | if (!value) | |
725 | return; | |
2211d5ba | 726 | if (size < sizeof(struct posix_acl_xattr_header)) |
5c8ebd57 CH |
727 | return; |
728 | if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION)) | |
729 | return; | |
730 | ||
731 | count = posix_acl_xattr_count(size); | |
732 | if (count < 0) | |
733 | return; | |
734 | if (count == 0) | |
735 | return; | |
736 | ||
737 | for (end = entry + count; entry != end; entry++) { | |
738 | switch(le16_to_cpu(entry->e_tag)) { | |
739 | case ACL_USER: | |
740 | uid = make_kuid(from, le32_to_cpu(entry->e_id)); | |
e65ce2a5 | 741 | if (from_user) |
44720713 | 742 | uid = mapped_kuid_user(mnt_userns, &init_user_ns, uid); |
e65ce2a5 | 743 | else |
44720713 | 744 | uid = mapped_kuid_fs(mnt_userns, &init_user_ns, uid); |
5c8ebd57 CH |
745 | entry->e_id = cpu_to_le32(from_kuid(to, uid)); |
746 | break; | |
747 | case ACL_GROUP: | |
748 | gid = make_kgid(from, le32_to_cpu(entry->e_id)); | |
e65ce2a5 | 749 | if (from_user) |
44720713 | 750 | gid = mapped_kgid_user(mnt_userns, &init_user_ns, gid); |
e65ce2a5 | 751 | else |
44720713 | 752 | gid = mapped_kgid_fs(mnt_userns, &init_user_ns, gid); |
5c8ebd57 CH |
753 | entry->e_id = cpu_to_le32(from_kgid(to, gid)); |
754 | break; | |
755 | default: | |
756 | break; | |
757 | } | |
758 | } | |
759 | } | |
760 | ||
e65ce2a5 CB |
761 | void posix_acl_fix_xattr_from_user(struct user_namespace *mnt_userns, |
762 | void *value, size_t size) | |
5c8ebd57 CH |
763 | { |
764 | struct user_namespace *user_ns = current_user_ns(); | |
e65ce2a5 | 765 | if ((user_ns == &init_user_ns) && (mnt_userns == &init_user_ns)) |
5c8ebd57 | 766 | return; |
e65ce2a5 CB |
767 | posix_acl_fix_xattr_userns(&init_user_ns, user_ns, mnt_userns, value, |
768 | size, true); | |
5c8ebd57 CH |
769 | } |
770 | ||
e65ce2a5 CB |
771 | void posix_acl_fix_xattr_to_user(struct user_namespace *mnt_userns, |
772 | void *value, size_t size) | |
5c8ebd57 CH |
773 | { |
774 | struct user_namespace *user_ns = current_user_ns(); | |
e65ce2a5 | 775 | if ((user_ns == &init_user_ns) && (mnt_userns == &init_user_ns)) |
5c8ebd57 | 776 | return; |
e65ce2a5 CB |
777 | posix_acl_fix_xattr_userns(user_ns, &init_user_ns, mnt_userns, value, |
778 | size, false); | |
5c8ebd57 CH |
779 | } |
780 | ||
781 | /* | |
782 | * Convert from extended attribute to in-memory representation. | |
783 | */ | |
784 | struct posix_acl * | |
785 | posix_acl_from_xattr(struct user_namespace *user_ns, | |
786 | const void *value, size_t size) | |
787 | { | |
2211d5ba AG |
788 | const struct posix_acl_xattr_header *header = value; |
789 | const struct posix_acl_xattr_entry *entry = (const void *)(header + 1), *end; | |
5c8ebd57 CH |
790 | int count; |
791 | struct posix_acl *acl; | |
792 | struct posix_acl_entry *acl_e; | |
793 | ||
794 | if (!value) | |
795 | return NULL; | |
2211d5ba | 796 | if (size < sizeof(struct posix_acl_xattr_header)) |
5c8ebd57 CH |
797 | return ERR_PTR(-EINVAL); |
798 | if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION)) | |
799 | return ERR_PTR(-EOPNOTSUPP); | |
800 | ||
801 | count = posix_acl_xattr_count(size); | |
802 | if (count < 0) | |
803 | return ERR_PTR(-EINVAL); | |
804 | if (count == 0) | |
805 | return NULL; | |
806 | ||
807 | acl = posix_acl_alloc(count, GFP_NOFS); | |
808 | if (!acl) | |
809 | return ERR_PTR(-ENOMEM); | |
810 | acl_e = acl->a_entries; | |
811 | ||
812 | for (end = entry + count; entry != end; acl_e++, entry++) { | |
813 | acl_e->e_tag = le16_to_cpu(entry->e_tag); | |
814 | acl_e->e_perm = le16_to_cpu(entry->e_perm); | |
815 | ||
816 | switch(acl_e->e_tag) { | |
817 | case ACL_USER_OBJ: | |
818 | case ACL_GROUP_OBJ: | |
819 | case ACL_MASK: | |
820 | case ACL_OTHER: | |
821 | break; | |
822 | ||
823 | case ACL_USER: | |
824 | acl_e->e_uid = | |
825 | make_kuid(user_ns, | |
826 | le32_to_cpu(entry->e_id)); | |
827 | if (!uid_valid(acl_e->e_uid)) | |
828 | goto fail; | |
829 | break; | |
830 | case ACL_GROUP: | |
831 | acl_e->e_gid = | |
832 | make_kgid(user_ns, | |
833 | le32_to_cpu(entry->e_id)); | |
834 | if (!gid_valid(acl_e->e_gid)) | |
835 | goto fail; | |
836 | break; | |
837 | ||
838 | default: | |
839 | goto fail; | |
840 | } | |
841 | } | |
842 | return acl; | |
843 | ||
844 | fail: | |
845 | posix_acl_release(acl); | |
846 | return ERR_PTR(-EINVAL); | |
847 | } | |
848 | EXPORT_SYMBOL (posix_acl_from_xattr); | |
849 | ||
850 | /* | |
851 | * Convert from in-memory to extended attribute representation. | |
852 | */ | |
853 | int | |
854 | posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl, | |
855 | void *buffer, size_t size) | |
856 | { | |
2211d5ba AG |
857 | struct posix_acl_xattr_header *ext_acl = buffer; |
858 | struct posix_acl_xattr_entry *ext_entry; | |
5c8ebd57 CH |
859 | int real_size, n; |
860 | ||
861 | real_size = posix_acl_xattr_size(acl->a_count); | |
862 | if (!buffer) | |
863 | return real_size; | |
864 | if (real_size > size) | |
865 | return -ERANGE; | |
47ba9734 | 866 | |
2211d5ba | 867 | ext_entry = (void *)(ext_acl + 1); |
5c8ebd57 CH |
868 | ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION); |
869 | ||
870 | for (n=0; n < acl->a_count; n++, ext_entry++) { | |
871 | const struct posix_acl_entry *acl_e = &acl->a_entries[n]; | |
872 | ext_entry->e_tag = cpu_to_le16(acl_e->e_tag); | |
873 | ext_entry->e_perm = cpu_to_le16(acl_e->e_perm); | |
874 | switch(acl_e->e_tag) { | |
875 | case ACL_USER: | |
876 | ext_entry->e_id = | |
877 | cpu_to_le32(from_kuid(user_ns, acl_e->e_uid)); | |
878 | break; | |
879 | case ACL_GROUP: | |
880 | ext_entry->e_id = | |
881 | cpu_to_le32(from_kgid(user_ns, acl_e->e_gid)); | |
882 | break; | |
883 | default: | |
884 | ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID); | |
885 | break; | |
886 | } | |
887 | } | |
888 | return real_size; | |
889 | } | |
890 | EXPORT_SYMBOL (posix_acl_to_xattr); | |
2aeccbe9 CH |
891 | |
892 | static int | |
d9a82a04 | 893 | posix_acl_xattr_get(const struct xattr_handler *handler, |
b296821a AV |
894 | struct dentry *unused, struct inode *inode, |
895 | const char *name, void *value, size_t size) | |
2aeccbe9 CH |
896 | { |
897 | struct posix_acl *acl; | |
898 | int error; | |
899 | ||
b296821a | 900 | if (!IS_POSIXACL(inode)) |
2aeccbe9 | 901 | return -EOPNOTSUPP; |
b296821a | 902 | if (S_ISLNK(inode->i_mode)) |
2aeccbe9 CH |
903 | return -EOPNOTSUPP; |
904 | ||
b296821a | 905 | acl = get_acl(inode, handler->flags); |
2aeccbe9 CH |
906 | if (IS_ERR(acl)) |
907 | return PTR_ERR(acl); | |
908 | if (acl == NULL) | |
909 | return -ENODATA; | |
910 | ||
911 | error = posix_acl_to_xattr(&init_user_ns, acl, value, size); | |
912 | posix_acl_release(acl); | |
913 | ||
914 | return error; | |
915 | } | |
916 | ||
485e71e8 | 917 | int |
e65ce2a5 CB |
918 | set_posix_acl(struct user_namespace *mnt_userns, struct inode *inode, |
919 | int type, struct posix_acl *acl) | |
2aeccbe9 | 920 | { |
2aeccbe9 CH |
921 | if (!IS_POSIXACL(inode)) |
922 | return -EOPNOTSUPP; | |
923 | if (!inode->i_op->set_acl) | |
924 | return -EOPNOTSUPP; | |
925 | ||
485e71e8 AG |
926 | if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode)) |
927 | return acl ? -EACCES : 0; | |
e65ce2a5 | 928 | if (!inode_owner_or_capable(mnt_userns, inode)) |
2aeccbe9 CH |
929 | return -EPERM; |
930 | ||
485e71e8 | 931 | if (acl) { |
a867d734 | 932 | int ret = posix_acl_valid(inode->i_sb->s_user_ns, acl); |
485e71e8 AG |
933 | if (ret) |
934 | return ret; | |
935 | } | |
549c7297 | 936 | return inode->i_op->set_acl(mnt_userns, inode, acl, type); |
485e71e8 AG |
937 | } |
938 | EXPORT_SYMBOL(set_posix_acl); | |
939 | ||
940 | static int | |
941 | posix_acl_xattr_set(const struct xattr_handler *handler, | |
e65ce2a5 CB |
942 | struct user_namespace *mnt_userns, |
943 | struct dentry *unused, struct inode *inode, | |
944 | const char *name, const void *value, size_t size, | |
945 | int flags) | |
485e71e8 AG |
946 | { |
947 | struct posix_acl *acl = NULL; | |
948 | int ret; | |
949 | ||
2aeccbe9 CH |
950 | if (value) { |
951 | acl = posix_acl_from_xattr(&init_user_ns, value, size); | |
952 | if (IS_ERR(acl)) | |
953 | return PTR_ERR(acl); | |
2aeccbe9 | 954 | } |
e65ce2a5 | 955 | ret = set_posix_acl(mnt_userns, inode, handler->flags, acl); |
2aeccbe9 CH |
956 | posix_acl_release(acl); |
957 | return ret; | |
958 | } | |
959 | ||
764a5c6b AG |
960 | static bool |
961 | posix_acl_xattr_list(struct dentry *dentry) | |
2aeccbe9 | 962 | { |
764a5c6b | 963 | return IS_POSIXACL(d_backing_inode(dentry)); |
2aeccbe9 CH |
964 | } |
965 | ||
966 | const struct xattr_handler posix_acl_access_xattr_handler = { | |
98e9cb57 | 967 | .name = XATTR_NAME_POSIX_ACL_ACCESS, |
2aeccbe9 CH |
968 | .flags = ACL_TYPE_ACCESS, |
969 | .list = posix_acl_xattr_list, | |
970 | .get = posix_acl_xattr_get, | |
971 | .set = posix_acl_xattr_set, | |
972 | }; | |
973 | EXPORT_SYMBOL_GPL(posix_acl_access_xattr_handler); | |
974 | ||
975 | const struct xattr_handler posix_acl_default_xattr_handler = { | |
98e9cb57 | 976 | .name = XATTR_NAME_POSIX_ACL_DEFAULT, |
2aeccbe9 CH |
977 | .flags = ACL_TYPE_DEFAULT, |
978 | .list = posix_acl_xattr_list, | |
979 | .get = posix_acl_xattr_get, | |
980 | .set = posix_acl_xattr_set, | |
981 | }; | |
982 | EXPORT_SYMBOL_GPL(posix_acl_default_xattr_handler); | |
feda821e | 983 | |
549c7297 CB |
984 | int simple_set_acl(struct user_namespace *mnt_userns, struct inode *inode, |
985 | struct posix_acl *acl, int type) | |
feda821e CH |
986 | { |
987 | int error; | |
988 | ||
989 | if (type == ACL_TYPE_ACCESS) { | |
549c7297 | 990 | error = posix_acl_update_mode(mnt_userns, inode, |
497de07d GZ |
991 | &inode->i_mode, &acl); |
992 | if (error) | |
993 | return error; | |
feda821e CH |
994 | } |
995 | ||
078cd827 | 996 | inode->i_ctime = current_time(inode); |
feda821e CH |
997 | set_cached_acl(inode, type, acl); |
998 | return 0; | |
999 | } | |
1000 | ||
1001 | int simple_acl_create(struct inode *dir, struct inode *inode) | |
1002 | { | |
1003 | struct posix_acl *default_acl, *acl; | |
1004 | int error; | |
1005 | ||
1006 | error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl); | |
1007 | if (error) | |
1008 | return error; | |
1009 | ||
1010 | set_cached_acl(inode, ACL_TYPE_DEFAULT, default_acl); | |
1011 | set_cached_acl(inode, ACL_TYPE_ACCESS, acl); | |
1012 | ||
1013 | if (default_acl) | |
1014 | posix_acl_release(default_acl); | |
1015 | if (acl) | |
1016 | posix_acl_release(acl); | |
1017 | return 0; | |
1018 | } |