Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/fs/ext3/acl.c | |
3 | * | |
4 | * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de> | |
5 | */ | |
6 | ||
7 | #include <linux/init.h> | |
8 | #include <linux/sched.h> | |
9 | #include <linux/slab.h> | |
10 | #include <linux/fs.h> | |
11 | #include <linux/ext3_jbd.h> | |
12 | #include <linux/ext3_fs.h> | |
13 | #include "xattr.h" | |
14 | #include "acl.h" | |
15 | ||
16 | /* | |
17 | * Convert from filesystem to in-memory representation. | |
18 | */ | |
19 | static struct posix_acl * | |
20 | ext3_acl_from_disk(const void *value, size_t size) | |
21 | { | |
22 | const char *end = (char *)value + size; | |
23 | int n, count; | |
24 | struct posix_acl *acl; | |
25 | ||
26 | if (!value) | |
27 | return NULL; | |
28 | if (size < sizeof(ext3_acl_header)) | |
29 | return ERR_PTR(-EINVAL); | |
30 | if (((ext3_acl_header *)value)->a_version != | |
31 | cpu_to_le32(EXT3_ACL_VERSION)) | |
32 | return ERR_PTR(-EINVAL); | |
33 | value = (char *)value + sizeof(ext3_acl_header); | |
34 | count = ext3_acl_count(size); | |
35 | if (count < 0) | |
36 | return ERR_PTR(-EINVAL); | |
37 | if (count == 0) | |
38 | return NULL; | |
39 | acl = posix_acl_alloc(count, GFP_KERNEL); | |
40 | if (!acl) | |
41 | return ERR_PTR(-ENOMEM); | |
42 | for (n=0; n < count; n++) { | |
43 | ext3_acl_entry *entry = | |
44 | (ext3_acl_entry *)value; | |
45 | if ((char *)value + sizeof(ext3_acl_entry_short) > end) | |
46 | goto fail; | |
47 | acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag); | |
48 | acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm); | |
49 | switch(acl->a_entries[n].e_tag) { | |
50 | case ACL_USER_OBJ: | |
51 | case ACL_GROUP_OBJ: | |
52 | case ACL_MASK: | |
53 | case ACL_OTHER: | |
54 | value = (char *)value + | |
55 | sizeof(ext3_acl_entry_short); | |
56 | acl->a_entries[n].e_id = ACL_UNDEFINED_ID; | |
57 | break; | |
58 | ||
59 | case ACL_USER: | |
60 | case ACL_GROUP: | |
61 | value = (char *)value + sizeof(ext3_acl_entry); | |
62 | if ((char *)value > end) | |
63 | goto fail; | |
64 | acl->a_entries[n].e_id = | |
65 | le32_to_cpu(entry->e_id); | |
66 | break; | |
67 | ||
68 | default: | |
69 | goto fail; | |
70 | } | |
71 | } | |
72 | if (value != end) | |
73 | goto fail; | |
74 | return acl; | |
75 | ||
76 | fail: | |
77 | posix_acl_release(acl); | |
78 | return ERR_PTR(-EINVAL); | |
79 | } | |
80 | ||
81 | /* | |
82 | * Convert from in-memory to filesystem representation. | |
83 | */ | |
84 | static void * | |
85 | ext3_acl_to_disk(const struct posix_acl *acl, size_t *size) | |
86 | { | |
87 | ext3_acl_header *ext_acl; | |
88 | char *e; | |
89 | size_t n; | |
90 | ||
91 | *size = ext3_acl_size(acl->a_count); | |
92 | ext_acl = (ext3_acl_header *)kmalloc(sizeof(ext3_acl_header) + | |
93 | acl->a_count * sizeof(ext3_acl_entry), GFP_KERNEL); | |
94 | if (!ext_acl) | |
95 | return ERR_PTR(-ENOMEM); | |
96 | ext_acl->a_version = cpu_to_le32(EXT3_ACL_VERSION); | |
97 | e = (char *)ext_acl + sizeof(ext3_acl_header); | |
98 | for (n=0; n < acl->a_count; n++) { | |
99 | ext3_acl_entry *entry = (ext3_acl_entry *)e; | |
100 | entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag); | |
101 | entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm); | |
102 | switch(acl->a_entries[n].e_tag) { | |
103 | case ACL_USER: | |
104 | case ACL_GROUP: | |
105 | entry->e_id = | |
106 | cpu_to_le32(acl->a_entries[n].e_id); | |
107 | e += sizeof(ext3_acl_entry); | |
108 | break; | |
109 | ||
110 | case ACL_USER_OBJ: | |
111 | case ACL_GROUP_OBJ: | |
112 | case ACL_MASK: | |
113 | case ACL_OTHER: | |
114 | e += sizeof(ext3_acl_entry_short); | |
115 | break; | |
116 | ||
117 | default: | |
118 | goto fail; | |
119 | } | |
120 | } | |
121 | return (char *)ext_acl; | |
122 | ||
123 | fail: | |
124 | kfree(ext_acl); | |
125 | return ERR_PTR(-EINVAL); | |
126 | } | |
127 | ||
128 | static inline struct posix_acl * | |
129 | ext3_iget_acl(struct inode *inode, struct posix_acl **i_acl) | |
130 | { | |
131 | struct posix_acl *acl = EXT3_ACL_NOT_CACHED; | |
132 | ||
133 | spin_lock(&inode->i_lock); | |
134 | if (*i_acl != EXT3_ACL_NOT_CACHED) | |
135 | acl = posix_acl_dup(*i_acl); | |
136 | spin_unlock(&inode->i_lock); | |
137 | ||
138 | return acl; | |
139 | } | |
140 | ||
141 | static inline void | |
142 | ext3_iset_acl(struct inode *inode, struct posix_acl **i_acl, | |
143 | struct posix_acl *acl) | |
144 | { | |
145 | spin_lock(&inode->i_lock); | |
146 | if (*i_acl != EXT3_ACL_NOT_CACHED) | |
147 | posix_acl_release(*i_acl); | |
148 | *i_acl = posix_acl_dup(acl); | |
149 | spin_unlock(&inode->i_lock); | |
150 | } | |
151 | ||
152 | /* | |
153 | * Inode operation get_posix_acl(). | |
154 | * | |
155 | * inode->i_sem: don't care | |
156 | */ | |
157 | static struct posix_acl * | |
158 | ext3_get_acl(struct inode *inode, int type) | |
159 | { | |
160 | struct ext3_inode_info *ei = EXT3_I(inode); | |
161 | int name_index; | |
162 | char *value = NULL; | |
163 | struct posix_acl *acl; | |
164 | int retval; | |
165 | ||
166 | if (!test_opt(inode->i_sb, POSIX_ACL)) | |
167 | return NULL; | |
168 | ||
169 | switch(type) { | |
170 | case ACL_TYPE_ACCESS: | |
171 | acl = ext3_iget_acl(inode, &ei->i_acl); | |
172 | if (acl != EXT3_ACL_NOT_CACHED) | |
173 | return acl; | |
174 | name_index = EXT3_XATTR_INDEX_POSIX_ACL_ACCESS; | |
175 | break; | |
176 | ||
177 | case ACL_TYPE_DEFAULT: | |
178 | acl = ext3_iget_acl(inode, &ei->i_default_acl); | |
179 | if (acl != EXT3_ACL_NOT_CACHED) | |
180 | return acl; | |
181 | name_index = EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT; | |
182 | break; | |
183 | ||
184 | default: | |
185 | return ERR_PTR(-EINVAL); | |
186 | } | |
187 | retval = ext3_xattr_get(inode, name_index, "", NULL, 0); | |
188 | if (retval > 0) { | |
189 | value = kmalloc(retval, GFP_KERNEL); | |
190 | if (!value) | |
191 | return ERR_PTR(-ENOMEM); | |
192 | retval = ext3_xattr_get(inode, name_index, "", value, retval); | |
193 | } | |
194 | if (retval > 0) | |
195 | acl = ext3_acl_from_disk(value, retval); | |
196 | else if (retval == -ENODATA || retval == -ENOSYS) | |
197 | acl = NULL; | |
198 | else | |
199 | acl = ERR_PTR(retval); | |
200 | kfree(value); | |
201 | ||
202 | if (!IS_ERR(acl)) { | |
203 | switch(type) { | |
204 | case ACL_TYPE_ACCESS: | |
205 | ext3_iset_acl(inode, &ei->i_acl, acl); | |
206 | break; | |
207 | ||
208 | case ACL_TYPE_DEFAULT: | |
209 | ext3_iset_acl(inode, &ei->i_default_acl, acl); | |
210 | break; | |
211 | } | |
212 | } | |
213 | return acl; | |
214 | } | |
215 | ||
216 | /* | |
217 | * Set the access or default ACL of an inode. | |
218 | * | |
219 | * inode->i_sem: down unless called from ext3_new_inode | |
220 | */ | |
221 | static int | |
222 | ext3_set_acl(handle_t *handle, struct inode *inode, int type, | |
223 | struct posix_acl *acl) | |
224 | { | |
225 | struct ext3_inode_info *ei = EXT3_I(inode); | |
226 | int name_index; | |
227 | void *value = NULL; | |
228 | size_t size; | |
229 | int error; | |
230 | ||
231 | if (S_ISLNK(inode->i_mode)) | |
232 | return -EOPNOTSUPP; | |
233 | ||
234 | switch(type) { | |
235 | case ACL_TYPE_ACCESS: | |
236 | name_index = EXT3_XATTR_INDEX_POSIX_ACL_ACCESS; | |
237 | if (acl) { | |
238 | mode_t mode = inode->i_mode; | |
239 | error = posix_acl_equiv_mode(acl, &mode); | |
240 | if (error < 0) | |
241 | return error; | |
242 | else { | |
243 | inode->i_mode = mode; | |
244 | ext3_mark_inode_dirty(handle, inode); | |
245 | if (error == 0) | |
246 | acl = NULL; | |
247 | } | |
248 | } | |
249 | break; | |
250 | ||
251 | case ACL_TYPE_DEFAULT: | |
252 | name_index = EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT; | |
253 | if (!S_ISDIR(inode->i_mode)) | |
254 | return acl ? -EACCES : 0; | |
255 | break; | |
256 | ||
257 | default: | |
258 | return -EINVAL; | |
259 | } | |
260 | if (acl) { | |
261 | value = ext3_acl_to_disk(acl, &size); | |
262 | if (IS_ERR(value)) | |
263 | return (int)PTR_ERR(value); | |
264 | } | |
265 | ||
266 | error = ext3_xattr_set_handle(handle, inode, name_index, "", | |
267 | value, size, 0); | |
268 | ||
269 | kfree(value); | |
270 | if (!error) { | |
271 | switch(type) { | |
272 | case ACL_TYPE_ACCESS: | |
273 | ext3_iset_acl(inode, &ei->i_acl, acl); | |
274 | break; | |
275 | ||
276 | case ACL_TYPE_DEFAULT: | |
277 | ext3_iset_acl(inode, &ei->i_default_acl, acl); | |
278 | break; | |
279 | } | |
280 | } | |
281 | return error; | |
282 | } | |
283 | ||
284 | static int | |
285 | ext3_check_acl(struct inode *inode, int mask) | |
286 | { | |
287 | struct posix_acl *acl = ext3_get_acl(inode, ACL_TYPE_ACCESS); | |
288 | ||
289 | if (acl) { | |
290 | int error = posix_acl_permission(inode, acl, mask); | |
291 | posix_acl_release(acl); | |
292 | return error; | |
293 | } | |
294 | ||
295 | return -EAGAIN; | |
296 | } | |
297 | ||
298 | int | |
299 | ext3_permission(struct inode *inode, int mask, struct nameidata *nd) | |
300 | { | |
301 | return generic_permission(inode, mask, ext3_check_acl); | |
302 | } | |
303 | ||
304 | /* | |
305 | * Initialize the ACLs of a new inode. Called from ext3_new_inode. | |
306 | * | |
307 | * dir->i_sem: down | |
308 | * inode->i_sem: up (access to inode is still exclusive) | |
309 | */ | |
310 | int | |
311 | ext3_init_acl(handle_t *handle, struct inode *inode, struct inode *dir) | |
312 | { | |
313 | struct posix_acl *acl = NULL; | |
314 | int error = 0; | |
315 | ||
316 | if (!S_ISLNK(inode->i_mode)) { | |
317 | if (test_opt(dir->i_sb, POSIX_ACL)) { | |
318 | acl = ext3_get_acl(dir, ACL_TYPE_DEFAULT); | |
319 | if (IS_ERR(acl)) | |
320 | return PTR_ERR(acl); | |
321 | } | |
322 | if (!acl) | |
323 | inode->i_mode &= ~current->fs->umask; | |
324 | } | |
325 | if (test_opt(inode->i_sb, POSIX_ACL) && acl) { | |
326 | struct posix_acl *clone; | |
327 | mode_t mode; | |
328 | ||
329 | if (S_ISDIR(inode->i_mode)) { | |
330 | error = ext3_set_acl(handle, inode, | |
331 | ACL_TYPE_DEFAULT, acl); | |
332 | if (error) | |
333 | goto cleanup; | |
334 | } | |
335 | clone = posix_acl_clone(acl, GFP_KERNEL); | |
336 | error = -ENOMEM; | |
337 | if (!clone) | |
338 | goto cleanup; | |
339 | ||
340 | mode = inode->i_mode; | |
341 | error = posix_acl_create_masq(clone, &mode); | |
342 | if (error >= 0) { | |
343 | inode->i_mode = mode; | |
344 | if (error > 0) { | |
345 | /* This is an extended ACL */ | |
346 | error = ext3_set_acl(handle, inode, | |
347 | ACL_TYPE_ACCESS, clone); | |
348 | } | |
349 | } | |
350 | posix_acl_release(clone); | |
351 | } | |
352 | cleanup: | |
353 | posix_acl_release(acl); | |
354 | return error; | |
355 | } | |
356 | ||
357 | /* | |
358 | * Does chmod for an inode that may have an Access Control List. The | |
359 | * inode->i_mode field must be updated to the desired value by the caller | |
360 | * before calling this function. | |
361 | * Returns 0 on success, or a negative error number. | |
362 | * | |
363 | * We change the ACL rather than storing some ACL entries in the file | |
364 | * mode permission bits (which would be more efficient), because that | |
365 | * would break once additional permissions (like ACL_APPEND, ACL_DELETE | |
366 | * for directories) are added. There are no more bits available in the | |
367 | * file mode. | |
368 | * | |
369 | * inode->i_sem: down | |
370 | */ | |
371 | int | |
372 | ext3_acl_chmod(struct inode *inode) | |
373 | { | |
374 | struct posix_acl *acl, *clone; | |
375 | int error; | |
376 | ||
377 | if (S_ISLNK(inode->i_mode)) | |
378 | return -EOPNOTSUPP; | |
379 | if (!test_opt(inode->i_sb, POSIX_ACL)) | |
380 | return 0; | |
381 | acl = ext3_get_acl(inode, ACL_TYPE_ACCESS); | |
382 | if (IS_ERR(acl) || !acl) | |
383 | return PTR_ERR(acl); | |
384 | clone = posix_acl_clone(acl, GFP_KERNEL); | |
385 | posix_acl_release(acl); | |
386 | if (!clone) | |
387 | return -ENOMEM; | |
388 | error = posix_acl_chmod_masq(clone, inode->i_mode); | |
389 | if (!error) { | |
390 | handle_t *handle; | |
391 | int retries = 0; | |
392 | ||
393 | retry: | |
394 | handle = ext3_journal_start(inode, EXT3_DATA_TRANS_BLOCKS); | |
395 | if (IS_ERR(handle)) { | |
396 | error = PTR_ERR(handle); | |
397 | ext3_std_error(inode->i_sb, error); | |
398 | goto out; | |
399 | } | |
400 | error = ext3_set_acl(handle, inode, ACL_TYPE_ACCESS, clone); | |
401 | ext3_journal_stop(handle); | |
402 | if (error == -ENOSPC && | |
403 | ext3_should_retry_alloc(inode->i_sb, &retries)) | |
404 | goto retry; | |
405 | } | |
406 | out: | |
407 | posix_acl_release(clone); | |
408 | return error; | |
409 | } | |
410 | ||
411 | /* | |
412 | * Extended attribute handlers | |
413 | */ | |
414 | static size_t | |
415 | ext3_xattr_list_acl_access(struct inode *inode, char *list, size_t list_len, | |
416 | const char *name, size_t name_len) | |
417 | { | |
418 | const size_t size = sizeof(XATTR_NAME_ACL_ACCESS); | |
419 | ||
420 | if (!test_opt(inode->i_sb, POSIX_ACL)) | |
421 | return 0; | |
422 | if (list && size <= list_len) | |
423 | memcpy(list, XATTR_NAME_ACL_ACCESS, size); | |
424 | return size; | |
425 | } | |
426 | ||
427 | static size_t | |
428 | ext3_xattr_list_acl_default(struct inode *inode, char *list, size_t list_len, | |
429 | const char *name, size_t name_len) | |
430 | { | |
431 | const size_t size = sizeof(XATTR_NAME_ACL_DEFAULT); | |
432 | ||
433 | if (!test_opt(inode->i_sb, POSIX_ACL)) | |
434 | return 0; | |
435 | if (list && size <= list_len) | |
436 | memcpy(list, XATTR_NAME_ACL_DEFAULT, size); | |
437 | return size; | |
438 | } | |
439 | ||
440 | static int | |
441 | ext3_xattr_get_acl(struct inode *inode, int type, void *buffer, size_t size) | |
442 | { | |
443 | struct posix_acl *acl; | |
444 | int error; | |
445 | ||
446 | if (!test_opt(inode->i_sb, POSIX_ACL)) | |
447 | return -EOPNOTSUPP; | |
448 | ||
449 | acl = ext3_get_acl(inode, type); | |
450 | if (IS_ERR(acl)) | |
451 | return PTR_ERR(acl); | |
452 | if (acl == NULL) | |
453 | return -ENODATA; | |
454 | error = posix_acl_to_xattr(acl, buffer, size); | |
455 | posix_acl_release(acl); | |
456 | ||
457 | return error; | |
458 | } | |
459 | ||
460 | static int | |
461 | ext3_xattr_get_acl_access(struct inode *inode, const char *name, | |
462 | void *buffer, size_t size) | |
463 | { | |
464 | if (strcmp(name, "") != 0) | |
465 | return -EINVAL; | |
466 | return ext3_xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size); | |
467 | } | |
468 | ||
469 | static int | |
470 | ext3_xattr_get_acl_default(struct inode *inode, const char *name, | |
471 | void *buffer, size_t size) | |
472 | { | |
473 | if (strcmp(name, "") != 0) | |
474 | return -EINVAL; | |
475 | return ext3_xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size); | |
476 | } | |
477 | ||
478 | static int | |
479 | ext3_xattr_set_acl(struct inode *inode, int type, const void *value, | |
480 | size_t size) | |
481 | { | |
482 | handle_t *handle; | |
483 | struct posix_acl *acl; | |
484 | int error, retries = 0; | |
485 | ||
486 | if (!test_opt(inode->i_sb, POSIX_ACL)) | |
487 | return -EOPNOTSUPP; | |
488 | if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER)) | |
489 | return -EPERM; | |
490 | ||
491 | if (value) { | |
492 | acl = posix_acl_from_xattr(value, size); | |
493 | if (IS_ERR(acl)) | |
494 | return PTR_ERR(acl); | |
495 | else if (acl) { | |
496 | error = posix_acl_valid(acl); | |
497 | if (error) | |
498 | goto release_and_out; | |
499 | } | |
500 | } else | |
501 | acl = NULL; | |
502 | ||
503 | retry: | |
504 | handle = ext3_journal_start(inode, EXT3_DATA_TRANS_BLOCKS); | |
505 | if (IS_ERR(handle)) | |
506 | return PTR_ERR(handle); | |
507 | error = ext3_set_acl(handle, inode, type, acl); | |
508 | ext3_journal_stop(handle); | |
509 | if (error == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries)) | |
510 | goto retry; | |
511 | ||
512 | release_and_out: | |
513 | posix_acl_release(acl); | |
514 | return error; | |
515 | } | |
516 | ||
517 | static int | |
518 | ext3_xattr_set_acl_access(struct inode *inode, const char *name, | |
519 | const void *value, size_t size, int flags) | |
520 | { | |
521 | if (strcmp(name, "") != 0) | |
522 | return -EINVAL; | |
523 | return ext3_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size); | |
524 | } | |
525 | ||
526 | static int | |
527 | ext3_xattr_set_acl_default(struct inode *inode, const char *name, | |
528 | const void *value, size_t size, int flags) | |
529 | { | |
530 | if (strcmp(name, "") != 0) | |
531 | return -EINVAL; | |
532 | return ext3_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size); | |
533 | } | |
534 | ||
535 | struct xattr_handler ext3_xattr_acl_access_handler = { | |
536 | .prefix = XATTR_NAME_ACL_ACCESS, | |
537 | .list = ext3_xattr_list_acl_access, | |
538 | .get = ext3_xattr_get_acl_access, | |
539 | .set = ext3_xattr_set_acl_access, | |
540 | }; | |
541 | ||
542 | struct xattr_handler ext3_xattr_acl_default_handler = { | |
543 | .prefix = XATTR_NAME_ACL_DEFAULT, | |
544 | .list = ext3_xattr_list_acl_default, | |
545 | .get = ext3_xattr_get_acl_default, | |
546 | .set = ext3_xattr_set_acl_default, | |
547 | }; |