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Source at commit fbf123cd4cc0c097fe9a99c90109ebb2a5e94a50 created 10 years 3 months ago. By Lars-Peter Clausen, dma: jz4740: Dequeue descriptor from active list before completing it | |
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1 | /* |
2 | * Copyright (C) 2002,2003 by Andreas Gruenbacher <a.gruenbacher@computer.org> |
3 | * |
4 | * Fixes from William Schumacher incorporated on 15 March 2001. |
5 | * (Reported by Charles Bertsch, <CBertsch@microtest.com>). |
6 | */ |
7 | |
8 | /* |
9 | * This file contains generic functions for manipulating |
10 | * POSIX 1003.1e draft standard 17 ACLs. |
11 | */ |
12 | |
13 | #include <linux/kernel.h> |
14 | #include <linux/slab.h> |
15 | #include <linux/atomic.h> |
16 | #include <linux/fs.h> |
17 | #include <linux/sched.h> |
18 | #include <linux/posix_acl.h> |
19 | #include <linux/posix_acl_xattr.h> |
20 | #include <linux/xattr.h> |
21 | #include <linux/export.h> |
22 | #include <linux/user_namespace.h> |
23 | |
24 | struct posix_acl **acl_by_type(struct inode *inode, int type) |
25 | { |
26 | switch (type) { |
27 | case ACL_TYPE_ACCESS: |
28 | return &inode->i_acl; |
29 | case ACL_TYPE_DEFAULT: |
30 | return &inode->i_default_acl; |
31 | default: |
32 | BUG(); |
33 | } |
34 | } |
35 | EXPORT_SYMBOL(acl_by_type); |
36 | |
37 | struct posix_acl *get_cached_acl(struct inode *inode, int type) |
38 | { |
39 | struct posix_acl **p = acl_by_type(inode, type); |
40 | struct posix_acl *acl = ACCESS_ONCE(*p); |
41 | if (acl) { |
42 | spin_lock(&inode->i_lock); |
43 | acl = *p; |
44 | if (acl != ACL_NOT_CACHED) |
45 | acl = posix_acl_dup(acl); |
46 | spin_unlock(&inode->i_lock); |
47 | } |
48 | return acl; |
49 | } |
50 | EXPORT_SYMBOL(get_cached_acl); |
51 | |
52 | struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type) |
53 | { |
54 | return rcu_dereference(*acl_by_type(inode, type)); |
55 | } |
56 | EXPORT_SYMBOL(get_cached_acl_rcu); |
57 | |
58 | void set_cached_acl(struct inode *inode, int type, struct posix_acl *acl) |
59 | { |
60 | struct posix_acl **p = acl_by_type(inode, type); |
61 | struct posix_acl *old; |
62 | spin_lock(&inode->i_lock); |
63 | old = *p; |
64 | rcu_assign_pointer(*p, posix_acl_dup(acl)); |
65 | spin_unlock(&inode->i_lock); |
66 | if (old != ACL_NOT_CACHED) |
67 | posix_acl_release(old); |
68 | } |
69 | EXPORT_SYMBOL(set_cached_acl); |
70 | |
71 | void forget_cached_acl(struct inode *inode, int type) |
72 | { |
73 | struct posix_acl **p = acl_by_type(inode, type); |
74 | struct posix_acl *old; |
75 | spin_lock(&inode->i_lock); |
76 | old = *p; |
77 | *p = ACL_NOT_CACHED; |
78 | spin_unlock(&inode->i_lock); |
79 | if (old != ACL_NOT_CACHED) |
80 | posix_acl_release(old); |
81 | } |
82 | EXPORT_SYMBOL(forget_cached_acl); |
83 | |
84 | void forget_all_cached_acls(struct inode *inode) |
85 | { |
86 | struct posix_acl *old_access, *old_default; |
87 | spin_lock(&inode->i_lock); |
88 | old_access = inode->i_acl; |
89 | old_default = inode->i_default_acl; |
90 | inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED; |
91 | spin_unlock(&inode->i_lock); |
92 | if (old_access != ACL_NOT_CACHED) |
93 | posix_acl_release(old_access); |
94 | if (old_default != ACL_NOT_CACHED) |
95 | posix_acl_release(old_default); |
96 | } |
97 | EXPORT_SYMBOL(forget_all_cached_acls); |
98 | |
99 | struct posix_acl *get_acl(struct inode *inode, int type) |
100 | { |
101 | struct posix_acl *acl; |
102 | |
103 | acl = get_cached_acl(inode, type); |
104 | if (acl != ACL_NOT_CACHED) |
105 | return acl; |
106 | |
107 | if (!IS_POSIXACL(inode)) |
108 | return NULL; |
109 | |
110 | /* |
111 | * A filesystem can force a ACL callback by just never filling the |
112 | * ACL cache. But normally you'd fill the cache either at inode |
113 | * instantiation time, or on the first ->get_acl call. |
114 | * |
115 | * If the filesystem doesn't have a get_acl() function at all, we'll |
116 | * just create the negative cache entry. |
117 | */ |
118 | if (!inode->i_op->get_acl) { |
119 | set_cached_acl(inode, type, NULL); |
120 | return NULL; |
121 | } |
122 | return inode->i_op->get_acl(inode, type); |
123 | } |
124 | EXPORT_SYMBOL(get_acl); |
125 | |
126 | /* |
127 | * Init a fresh posix_acl |
128 | */ |
129 | void |
130 | posix_acl_init(struct posix_acl *acl, int count) |
131 | { |
132 | atomic_set(&acl->a_refcount, 1); |
133 | acl->a_count = count; |
134 | } |
135 | EXPORT_SYMBOL(posix_acl_init); |
136 | |
137 | /* |
138 | * Allocate a new ACL with the specified number of entries. |
139 | */ |
140 | struct posix_acl * |
141 | posix_acl_alloc(int count, gfp_t flags) |
142 | { |
143 | const size_t size = sizeof(struct posix_acl) + |
144 | count * sizeof(struct posix_acl_entry); |
145 | struct posix_acl *acl = kmalloc(size, flags); |
146 | if (acl) |
147 | posix_acl_init(acl, count); |
148 | return acl; |
149 | } |
150 | EXPORT_SYMBOL(posix_acl_alloc); |
151 | |
152 | /* |
153 | * Clone an ACL. |
154 | */ |
155 | static struct posix_acl * |
156 | posix_acl_clone(const struct posix_acl *acl, gfp_t flags) |
157 | { |
158 | struct posix_acl *clone = NULL; |
159 | |
160 | if (acl) { |
161 | int size = sizeof(struct posix_acl) + acl->a_count * |
162 | sizeof(struct posix_acl_entry); |
163 | clone = kmemdup(acl, size, flags); |
164 | if (clone) |
165 | atomic_set(&clone->a_refcount, 1); |
166 | } |
167 | return clone; |
168 | } |
169 | |
170 | /* |
171 | * Check if an acl is valid. Returns 0 if it is, or -E... otherwise. |
172 | */ |
173 | int |
174 | posix_acl_valid(const struct posix_acl *acl) |
175 | { |
176 | const struct posix_acl_entry *pa, *pe; |
177 | int state = ACL_USER_OBJ; |
178 | int needs_mask = 0; |
179 | |
180 | FOREACH_ACL_ENTRY(pa, acl, pe) { |
181 | if (pa->e_perm & ~(ACL_READ|ACL_WRITE|ACL_EXECUTE)) |
182 | return -EINVAL; |
183 | switch (pa->e_tag) { |
184 | case ACL_USER_OBJ: |
185 | if (state == ACL_USER_OBJ) { |
186 | state = ACL_USER; |
187 | break; |
188 | } |
189 | return -EINVAL; |
190 | |
191 | case ACL_USER: |
192 | if (state != ACL_USER) |
193 | return -EINVAL; |
194 | if (!uid_valid(pa->e_uid)) |
195 | return -EINVAL; |
196 | needs_mask = 1; |
197 | break; |
198 | |
199 | case ACL_GROUP_OBJ: |
200 | if (state == ACL_USER) { |
201 | state = ACL_GROUP; |
202 | break; |
203 | } |
204 | return -EINVAL; |
205 | |
206 | case ACL_GROUP: |
207 | if (state != ACL_GROUP) |
208 | return -EINVAL; |
209 | if (!gid_valid(pa->e_gid)) |
210 | return -EINVAL; |
211 | needs_mask = 1; |
212 | break; |
213 | |
214 | case ACL_MASK: |
215 | if (state != ACL_GROUP) |
216 | return -EINVAL; |
217 | state = ACL_OTHER; |
218 | break; |
219 | |
220 | case ACL_OTHER: |
221 | if (state == ACL_OTHER || |
222 | (state == ACL_GROUP && !needs_mask)) { |
223 | state = 0; |
224 | break; |
225 | } |
226 | return -EINVAL; |
227 | |
228 | default: |
229 | return -EINVAL; |
230 | } |
231 | } |
232 | if (state == 0) |
233 | return 0; |
234 | return -EINVAL; |
235 | } |
236 | EXPORT_SYMBOL(posix_acl_valid); |
237 | |
238 | /* |
239 | * Returns 0 if the acl can be exactly represented in the traditional |
240 | * file mode permission bits, or else 1. Returns -E... on error. |
241 | */ |
242 | int |
243 | posix_acl_equiv_mode(const struct posix_acl *acl, umode_t *mode_p) |
244 | { |
245 | const struct posix_acl_entry *pa, *pe; |
246 | umode_t mode = 0; |
247 | int not_equiv = 0; |
248 | |
249 | /* |
250 | * A null ACL can always be presented as mode bits. |
251 | */ |
252 | if (!acl) |
253 | return 0; |
254 | |
255 | FOREACH_ACL_ENTRY(pa, acl, pe) { |
256 | switch (pa->e_tag) { |
257 | case ACL_USER_OBJ: |
258 | mode |= (pa->e_perm & S_IRWXO) << 6; |
259 | break; |
260 | case ACL_GROUP_OBJ: |
261 | mode |= (pa->e_perm & S_IRWXO) << 3; |
262 | break; |
263 | case ACL_OTHER: |
264 | mode |= pa->e_perm & S_IRWXO; |
265 | break; |
266 | case ACL_MASK: |
267 | mode = (mode & ~S_IRWXG) | |
268 | ((pa->e_perm & S_IRWXO) << 3); |
269 | not_equiv = 1; |
270 | break; |
271 | case ACL_USER: |
272 | case ACL_GROUP: |
273 | not_equiv = 1; |
274 | break; |
275 | default: |
276 | return -EINVAL; |
277 | } |
278 | } |
279 | if (mode_p) |
280 | *mode_p = (*mode_p & ~S_IRWXUGO) | mode; |
281 | return not_equiv; |
282 | } |
283 | EXPORT_SYMBOL(posix_acl_equiv_mode); |
284 | |
285 | /* |
286 | * Create an ACL representing the file mode permission bits of an inode. |
287 | */ |
288 | struct posix_acl * |
289 | posix_acl_from_mode(umode_t mode, gfp_t flags) |
290 | { |
291 | struct posix_acl *acl = posix_acl_alloc(3, flags); |
292 | if (!acl) |
293 | return ERR_PTR(-ENOMEM); |
294 | |
295 | acl->a_entries[0].e_tag = ACL_USER_OBJ; |
296 | acl->a_entries[0].e_perm = (mode & S_IRWXU) >> 6; |
297 | |
298 | acl->a_entries[1].e_tag = ACL_GROUP_OBJ; |
299 | acl->a_entries[1].e_perm = (mode & S_IRWXG) >> 3; |
300 | |
301 | acl->a_entries[2].e_tag = ACL_OTHER; |
302 | acl->a_entries[2].e_perm = (mode & S_IRWXO); |
303 | return acl; |
304 | } |
305 | EXPORT_SYMBOL(posix_acl_from_mode); |
306 | |
307 | /* |
308 | * Return 0 if current is granted want access to the inode |
309 | * by the acl. Returns -E... otherwise. |
310 | */ |
311 | int |
312 | posix_acl_permission(struct inode *inode, const struct posix_acl *acl, int want) |
313 | { |
314 | const struct posix_acl_entry *pa, *pe, *mask_obj; |
315 | int found = 0; |
316 | |
317 | want &= MAY_READ | MAY_WRITE | MAY_EXEC | MAY_NOT_BLOCK; |
318 | |
319 | FOREACH_ACL_ENTRY(pa, acl, pe) { |
320 | switch(pa->e_tag) { |
321 | case ACL_USER_OBJ: |
322 | /* (May have been checked already) */ |
323 | if (uid_eq(inode->i_uid, current_fsuid())) |
324 | goto check_perm; |
325 | break; |
326 | case ACL_USER: |
327 | if (uid_eq(pa->e_uid, current_fsuid())) |
328 | goto mask; |
329 | break; |
330 | case ACL_GROUP_OBJ: |
331 | if (in_group_p(inode->i_gid)) { |
332 | found = 1; |
333 | if ((pa->e_perm & want) == want) |
334 | goto mask; |
335 | } |
336 | break; |
337 | case ACL_GROUP: |
338 | if (in_group_p(pa->e_gid)) { |
339 | found = 1; |
340 | if ((pa->e_perm & want) == want) |
341 | goto mask; |
342 | } |
343 | break; |
344 | case ACL_MASK: |
345 | break; |
346 | case ACL_OTHER: |
347 | if (found) |
348 | return -EACCES; |
349 | else |
350 | goto check_perm; |
351 | default: |
352 | return -EIO; |
353 | } |
354 | } |
355 | return -EIO; |
356 | |
357 | mask: |
358 | for (mask_obj = pa+1; mask_obj != pe; mask_obj++) { |
359 | if (mask_obj->e_tag == ACL_MASK) { |
360 | if ((pa->e_perm & mask_obj->e_perm & want) == want) |
361 | return 0; |
362 | return -EACCES; |
363 | } |
364 | } |
365 | |
366 | check_perm: |
367 | if ((pa->e_perm & want) == want) |
368 | return 0; |
369 | return -EACCES; |
370 | } |
371 | |
372 | /* |
373 | * Modify acl when creating a new inode. The caller must ensure the acl is |
374 | * only referenced once. |
375 | * |
376 | * mode_p initially must contain the mode parameter to the open() / creat() |
377 | * system calls. All permissions that are not granted by the acl are removed. |
378 | * The permissions in the acl are changed to reflect the mode_p parameter. |
379 | */ |
380 | static int posix_acl_create_masq(struct posix_acl *acl, umode_t *mode_p) |
381 | { |
382 | struct posix_acl_entry *pa, *pe; |
383 | struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL; |
384 | umode_t mode = *mode_p; |
385 | int not_equiv = 0; |
386 | |
387 | /* assert(atomic_read(acl->a_refcount) == 1); */ |
388 | |
389 | FOREACH_ACL_ENTRY(pa, acl, pe) { |
390 | switch(pa->e_tag) { |
391 | case ACL_USER_OBJ: |
392 | pa->e_perm &= (mode >> 6) | ~S_IRWXO; |
393 | mode &= (pa->e_perm << 6) | ~S_IRWXU; |
394 | break; |
395 | |
396 | case ACL_USER: |
397 | case ACL_GROUP: |
398 | not_equiv = 1; |
399 | break; |
400 | |
401 | case ACL_GROUP_OBJ: |
402 | group_obj = pa; |
403 | break; |
404 | |
405 | case ACL_OTHER: |
406 | pa->e_perm &= mode | ~S_IRWXO; |
407 | mode &= pa->e_perm | ~S_IRWXO; |
408 | break; |
409 | |
410 | case ACL_MASK: |
411 | mask_obj = pa; |
412 | not_equiv = 1; |
413 | break; |
414 | |
415 | default: |
416 | return -EIO; |
417 | } |
418 | } |
419 | |
420 | if (mask_obj) { |
421 | mask_obj->e_perm &= (mode >> 3) | ~S_IRWXO; |
422 | mode &= (mask_obj->e_perm << 3) | ~S_IRWXG; |
423 | } else { |
424 | if (!group_obj) |
425 | return -EIO; |
426 | group_obj->e_perm &= (mode >> 3) | ~S_IRWXO; |
427 | mode &= (group_obj->e_perm << 3) | ~S_IRWXG; |
428 | } |
429 | |
430 | *mode_p = (*mode_p & ~S_IRWXUGO) | mode; |
431 | return not_equiv; |
432 | } |
433 | |
434 | /* |
435 | * Modify the ACL for the chmod syscall. |
436 | */ |
437 | static int __posix_acl_chmod_masq(struct posix_acl *acl, umode_t mode) |
438 | { |
439 | struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL; |
440 | struct posix_acl_entry *pa, *pe; |
441 | |
442 | /* assert(atomic_read(acl->a_refcount) == 1); */ |
443 | |
444 | FOREACH_ACL_ENTRY(pa, acl, pe) { |
445 | switch(pa->e_tag) { |
446 | case ACL_USER_OBJ: |
447 | pa->e_perm = (mode & S_IRWXU) >> 6; |
448 | break; |
449 | |
450 | case ACL_USER: |
451 | case ACL_GROUP: |
452 | break; |
453 | |
454 | case ACL_GROUP_OBJ: |
455 | group_obj = pa; |
456 | break; |
457 | |
458 | case ACL_MASK: |
459 | mask_obj = pa; |
460 | break; |
461 | |
462 | case ACL_OTHER: |
463 | pa->e_perm = (mode & S_IRWXO); |
464 | break; |
465 | |
466 | default: |
467 | return -EIO; |
468 | } |
469 | } |
470 | |
471 | if (mask_obj) { |
472 | mask_obj->e_perm = (mode & S_IRWXG) >> 3; |
473 | } else { |
474 | if (!group_obj) |
475 | return -EIO; |
476 | group_obj->e_perm = (mode & S_IRWXG) >> 3; |
477 | } |
478 | |
479 | return 0; |
480 | } |
481 | |
482 | int |
483 | __posix_acl_create(struct posix_acl **acl, gfp_t gfp, umode_t *mode_p) |
484 | { |
485 | struct posix_acl *clone = posix_acl_clone(*acl, gfp); |
486 | int err = -ENOMEM; |
487 | if (clone) { |
488 | err = posix_acl_create_masq(clone, mode_p); |
489 | if (err < 0) { |
490 | posix_acl_release(clone); |
491 | clone = NULL; |
492 | } |
493 | } |
494 | posix_acl_release(*acl); |
495 | *acl = clone; |
496 | return err; |
497 | } |
498 | EXPORT_SYMBOL(__posix_acl_create); |
499 | |
500 | int |
501 | __posix_acl_chmod(struct posix_acl **acl, gfp_t gfp, umode_t mode) |
502 | { |
503 | struct posix_acl *clone = posix_acl_clone(*acl, gfp); |
504 | int err = -ENOMEM; |
505 | if (clone) { |
506 | err = __posix_acl_chmod_masq(clone, mode); |
507 | if (err) { |
508 | posix_acl_release(clone); |
509 | clone = NULL; |
510 | } |
511 | } |
512 | posix_acl_release(*acl); |
513 | *acl = clone; |
514 | return err; |
515 | } |
516 | EXPORT_SYMBOL(__posix_acl_chmod); |
517 | |
518 | int |
519 | posix_acl_chmod(struct inode *inode, umode_t mode) |
520 | { |
521 | struct posix_acl *acl; |
522 | int ret = 0; |
523 | |
524 | if (!IS_POSIXACL(inode)) |
525 | return 0; |
526 | if (!inode->i_op->set_acl) |
527 | return -EOPNOTSUPP; |
528 | |
529 | acl = get_acl(inode, ACL_TYPE_ACCESS); |
530 | if (IS_ERR_OR_NULL(acl)) { |
531 | if (acl == ERR_PTR(-EOPNOTSUPP)) |
532 | return 0; |
533 | return PTR_ERR(acl); |
534 | } |
535 | |
536 | ret = __posix_acl_chmod(&acl, GFP_KERNEL, mode); |
537 | if (ret) |
538 | return ret; |
539 | ret = inode->i_op->set_acl(inode, acl, ACL_TYPE_ACCESS); |
540 | posix_acl_release(acl); |
541 | return ret; |
542 | } |
543 | EXPORT_SYMBOL(posix_acl_chmod); |
544 | |
545 | int |
546 | posix_acl_create(struct inode *dir, umode_t *mode, |
547 | struct posix_acl **default_acl, struct posix_acl **acl) |
548 | { |
549 | struct posix_acl *p; |
550 | int ret; |
551 | |
552 | if (S_ISLNK(*mode) || !IS_POSIXACL(dir)) |
553 | goto no_acl; |
554 | |
555 | p = get_acl(dir, ACL_TYPE_DEFAULT); |
556 | if (IS_ERR(p)) { |
557 | if (p == ERR_PTR(-EOPNOTSUPP)) |
558 | goto apply_umask; |
559 | return PTR_ERR(p); |
560 | } |
561 | |
562 | if (!p) |
563 | goto apply_umask; |
564 | |
565 | *acl = posix_acl_clone(p, GFP_NOFS); |
566 | if (!*acl) |
567 | return -ENOMEM; |
568 | |
569 | ret = posix_acl_create_masq(*acl, mode); |
570 | if (ret < 0) { |
571 | posix_acl_release(*acl); |
572 | return -ENOMEM; |
573 | } |
574 | |
575 | if (ret == 0) { |
576 | posix_acl_release(*acl); |
577 | *acl = NULL; |
578 | } |
579 | |
580 | if (!S_ISDIR(*mode)) { |
581 | posix_acl_release(p); |
582 | *default_acl = NULL; |
583 | } else { |
584 | *default_acl = p; |
585 | } |
586 | return 0; |
587 | |
588 | apply_umask: |
589 | *mode &= ~current_umask(); |
590 | no_acl: |
591 | *default_acl = NULL; |
592 | *acl = NULL; |
593 | return 0; |
594 | } |
595 | EXPORT_SYMBOL_GPL(posix_acl_create); |
596 | |
597 | /* |
598 | * Fix up the uids and gids in posix acl extended attributes in place. |
599 | */ |
600 | static void posix_acl_fix_xattr_userns( |
601 | struct user_namespace *to, struct user_namespace *from, |
602 | void *value, size_t size) |
603 | { |
604 | posix_acl_xattr_header *header = (posix_acl_xattr_header *)value; |
605 | posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end; |
606 | int count; |
607 | kuid_t uid; |
608 | kgid_t gid; |
609 | |
610 | if (!value) |
611 | return; |
612 | if (size < sizeof(posix_acl_xattr_header)) |
613 | return; |
614 | if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION)) |
615 | return; |
616 | |
617 | count = posix_acl_xattr_count(size); |
618 | if (count < 0) |
619 | return; |
620 | if (count == 0) |
621 | return; |
622 | |
623 | for (end = entry + count; entry != end; entry++) { |
624 | switch(le16_to_cpu(entry->e_tag)) { |
625 | case ACL_USER: |
626 | uid = make_kuid(from, le32_to_cpu(entry->e_id)); |
627 | entry->e_id = cpu_to_le32(from_kuid(to, uid)); |
628 | break; |
629 | case ACL_GROUP: |
630 | gid = make_kgid(from, le32_to_cpu(entry->e_id)); |
631 | entry->e_id = cpu_to_le32(from_kgid(to, gid)); |
632 | break; |
633 | default: |
634 | break; |
635 | } |
636 | } |
637 | } |
638 | |
639 | void posix_acl_fix_xattr_from_user(void *value, size_t size) |
640 | { |
641 | struct user_namespace *user_ns = current_user_ns(); |
642 | if (user_ns == &init_user_ns) |
643 | return; |
644 | posix_acl_fix_xattr_userns(&init_user_ns, user_ns, value, size); |
645 | } |
646 | |
647 | void posix_acl_fix_xattr_to_user(void *value, size_t size) |
648 | { |
649 | struct user_namespace *user_ns = current_user_ns(); |
650 | if (user_ns == &init_user_ns) |
651 | return; |
652 | posix_acl_fix_xattr_userns(user_ns, &init_user_ns, value, size); |
653 | } |
654 | |
655 | /* |
656 | * Convert from extended attribute to in-memory representation. |
657 | */ |
658 | struct posix_acl * |
659 | posix_acl_from_xattr(struct user_namespace *user_ns, |
660 | const void *value, size_t size) |
661 | { |
662 | posix_acl_xattr_header *header = (posix_acl_xattr_header *)value; |
663 | posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end; |
664 | int count; |
665 | struct posix_acl *acl; |
666 | struct posix_acl_entry *acl_e; |
667 | |
668 | if (!value) |
669 | return NULL; |
670 | if (size < sizeof(posix_acl_xattr_header)) |
671 | return ERR_PTR(-EINVAL); |
672 | if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION)) |
673 | return ERR_PTR(-EOPNOTSUPP); |
674 | |
675 | count = posix_acl_xattr_count(size); |
676 | if (count < 0) |
677 | return ERR_PTR(-EINVAL); |
678 | if (count == 0) |
679 | return NULL; |
680 | |
681 | acl = posix_acl_alloc(count, GFP_NOFS); |
682 | if (!acl) |
683 | return ERR_PTR(-ENOMEM); |
684 | acl_e = acl->a_entries; |
685 | |
686 | for (end = entry + count; entry != end; acl_e++, entry++) { |
687 | acl_e->e_tag = le16_to_cpu(entry->e_tag); |
688 | acl_e->e_perm = le16_to_cpu(entry->e_perm); |
689 | |
690 | switch(acl_e->e_tag) { |
691 | case ACL_USER_OBJ: |
692 | case ACL_GROUP_OBJ: |
693 | case ACL_MASK: |
694 | case ACL_OTHER: |
695 | break; |
696 | |
697 | case ACL_USER: |
698 | acl_e->e_uid = |
699 | make_kuid(user_ns, |
700 | le32_to_cpu(entry->e_id)); |
701 | if (!uid_valid(acl_e->e_uid)) |
702 | goto fail; |
703 | break; |
704 | case ACL_GROUP: |
705 | acl_e->e_gid = |
706 | make_kgid(user_ns, |
707 | le32_to_cpu(entry->e_id)); |
708 | if (!gid_valid(acl_e->e_gid)) |
709 | goto fail; |
710 | break; |
711 | |
712 | default: |
713 | goto fail; |
714 | } |
715 | } |
716 | return acl; |
717 | |
718 | fail: |
719 | posix_acl_release(acl); |
720 | return ERR_PTR(-EINVAL); |
721 | } |
722 | EXPORT_SYMBOL (posix_acl_from_xattr); |
723 | |
724 | /* |
725 | * Convert from in-memory to extended attribute representation. |
726 | */ |
727 | int |
728 | posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl, |
729 | void *buffer, size_t size) |
730 | { |
731 | posix_acl_xattr_header *ext_acl = (posix_acl_xattr_header *)buffer; |
732 | posix_acl_xattr_entry *ext_entry; |
733 | int real_size, n; |
734 | |
735 | real_size = posix_acl_xattr_size(acl->a_count); |
736 | if (!buffer) |
737 | return real_size; |
738 | if (real_size > size) |
739 | return -ERANGE; |
740 | |
741 | ext_entry = ext_acl->a_entries; |
742 | ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION); |
743 | |
744 | for (n=0; n < acl->a_count; n++, ext_entry++) { |
745 | const struct posix_acl_entry *acl_e = &acl->a_entries[n]; |
746 | ext_entry->e_tag = cpu_to_le16(acl_e->e_tag); |
747 | ext_entry->e_perm = cpu_to_le16(acl_e->e_perm); |
748 | switch(acl_e->e_tag) { |
749 | case ACL_USER: |
750 | ext_entry->e_id = |
751 | cpu_to_le32(from_kuid(user_ns, acl_e->e_uid)); |
752 | break; |
753 | case ACL_GROUP: |
754 | ext_entry->e_id = |
755 | cpu_to_le32(from_kgid(user_ns, acl_e->e_gid)); |
756 | break; |
757 | default: |
758 | ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID); |
759 | break; |
760 | } |
761 | } |
762 | return real_size; |
763 | } |
764 | EXPORT_SYMBOL (posix_acl_to_xattr); |
765 | |
766 | static int |
767 | posix_acl_xattr_get(struct dentry *dentry, const char *name, |
768 | void *value, size_t size, int type) |
769 | { |
770 | struct posix_acl *acl; |
771 | int error; |
772 | |
773 | if (!IS_POSIXACL(dentry->d_inode)) |
774 | return -EOPNOTSUPP; |
775 | if (S_ISLNK(dentry->d_inode->i_mode)) |
776 | return -EOPNOTSUPP; |
777 | |
778 | acl = get_acl(dentry->d_inode, type); |
779 | if (IS_ERR(acl)) |
780 | return PTR_ERR(acl); |
781 | if (acl == NULL) |
782 | return -ENODATA; |
783 | |
784 | error = posix_acl_to_xattr(&init_user_ns, acl, value, size); |
785 | posix_acl_release(acl); |
786 | |
787 | return error; |
788 | } |
789 | |
790 | static int |
791 | posix_acl_xattr_set(struct dentry *dentry, const char *name, |
792 | const void *value, size_t size, int flags, int type) |
793 | { |
794 | struct inode *inode = dentry->d_inode; |
795 | struct posix_acl *acl = NULL; |
796 | int ret; |
797 | |
798 | if (!IS_POSIXACL(inode)) |
799 | return -EOPNOTSUPP; |
800 | if (!inode->i_op->set_acl) |
801 | return -EOPNOTSUPP; |
802 | |
803 | if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode)) |
804 | return value ? -EACCES : 0; |
805 | if (!inode_owner_or_capable(inode)) |
806 | return -EPERM; |
807 | |
808 | if (value) { |
809 | acl = posix_acl_from_xattr(&init_user_ns, value, size); |
810 | if (IS_ERR(acl)) |
811 | return PTR_ERR(acl); |
812 | |
813 | if (acl) { |
814 | ret = posix_acl_valid(acl); |
815 | if (ret) |
816 | goto out; |
817 | } |
818 | } |
819 | |
820 | ret = inode->i_op->set_acl(inode, acl, type); |
821 | out: |
822 | posix_acl_release(acl); |
823 | return ret; |
824 | } |
825 | |
826 | static size_t |
827 | posix_acl_xattr_list(struct dentry *dentry, char *list, size_t list_size, |
828 | const char *name, size_t name_len, int type) |
829 | { |
830 | const char *xname; |
831 | size_t size; |
832 | |
833 | if (!IS_POSIXACL(dentry->d_inode)) |
834 | return -EOPNOTSUPP; |
835 | if (S_ISLNK(dentry->d_inode->i_mode)) |
836 | return -EOPNOTSUPP; |
837 | |
838 | if (type == ACL_TYPE_ACCESS) |
839 | xname = POSIX_ACL_XATTR_ACCESS; |
840 | else |
841 | xname = POSIX_ACL_XATTR_DEFAULT; |
842 | |
843 | size = strlen(xname) + 1; |
844 | if (list && size <= list_size) |
845 | memcpy(list, xname, size); |
846 | return size; |
847 | } |
848 | |
849 | const struct xattr_handler posix_acl_access_xattr_handler = { |
850 | .prefix = POSIX_ACL_XATTR_ACCESS, |
851 | .flags = ACL_TYPE_ACCESS, |
852 | .list = posix_acl_xattr_list, |
853 | .get = posix_acl_xattr_get, |
854 | .set = posix_acl_xattr_set, |
855 | }; |
856 | EXPORT_SYMBOL_GPL(posix_acl_access_xattr_handler); |
857 | |
858 | const struct xattr_handler posix_acl_default_xattr_handler = { |
859 | .prefix = POSIX_ACL_XATTR_DEFAULT, |
860 | .flags = ACL_TYPE_DEFAULT, |
861 | .list = posix_acl_xattr_list, |
862 | .get = posix_acl_xattr_get, |
863 | .set = posix_acl_xattr_set, |
864 | }; |
865 | EXPORT_SYMBOL_GPL(posix_acl_default_xattr_handler); |
866 | |
867 | int simple_set_acl(struct inode *inode, struct posix_acl *acl, int type) |
868 | { |
869 | int error; |
870 | |
871 | if (type == ACL_TYPE_ACCESS) { |
872 | error = posix_acl_equiv_mode(acl, &inode->i_mode); |
873 | if (error < 0) |
874 | return 0; |
875 | if (error == 0) |
876 | acl = NULL; |
877 | } |
878 | |
879 | inode->i_ctime = CURRENT_TIME; |
880 | set_cached_acl(inode, type, acl); |
881 | return 0; |
882 | } |
883 | |
884 | int simple_acl_create(struct inode *dir, struct inode *inode) |
885 | { |
886 | struct posix_acl *default_acl, *acl; |
887 | int error; |
888 | |
889 | error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl); |
890 | if (error) |
891 | return error; |
892 | |
893 | set_cached_acl(inode, ACL_TYPE_DEFAULT, default_acl); |
894 | set_cached_acl(inode, ACL_TYPE_ACCESS, acl); |
895 | |
896 | if (default_acl) |
897 | posix_acl_release(default_acl); |
898 | if (acl) |
899 | posix_acl_release(acl); |
900 | return 0; |
901 | } |
902 |
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