Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/fs/ext2/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 "ext2.h" | |
12 | #include "xattr.h" | |
13 | #include "acl.h" | |
14 | ||
15 | /* | |
16 | * Convert from filesystem to in-memory representation. | |
17 | */ | |
18 | static struct posix_acl * | |
19 | ext2_acl_from_disk(const void *value, size_t size) | |
20 | { | |
21 | const char *end = (char *)value + size; | |
22 | int n, count; | |
23 | struct posix_acl *acl; | |
24 | ||
25 | if (!value) | |
26 | return NULL; | |
27 | if (size < sizeof(ext2_acl_header)) | |
28 | return ERR_PTR(-EINVAL); | |
29 | if (((ext2_acl_header *)value)->a_version != | |
30 | cpu_to_le32(EXT2_ACL_VERSION)) | |
31 | return ERR_PTR(-EINVAL); | |
32 | value = (char *)value + sizeof(ext2_acl_header); | |
33 | count = ext2_acl_count(size); | |
34 | if (count < 0) | |
35 | return ERR_PTR(-EINVAL); | |
36 | if (count == 0) | |
37 | return NULL; | |
38 | acl = posix_acl_alloc(count, GFP_KERNEL); | |
39 | if (!acl) | |
40 | return ERR_PTR(-ENOMEM); | |
41 | for (n=0; n < count; n++) { | |
42 | ext2_acl_entry *entry = | |
43 | (ext2_acl_entry *)value; | |
44 | if ((char *)value + sizeof(ext2_acl_entry_short) > end) | |
45 | goto fail; | |
46 | acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag); | |
47 | acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm); | |
48 | switch(acl->a_entries[n].e_tag) { | |
49 | case ACL_USER_OBJ: | |
50 | case ACL_GROUP_OBJ: | |
51 | case ACL_MASK: | |
52 | case ACL_OTHER: | |
53 | value = (char *)value + | |
54 | sizeof(ext2_acl_entry_short); | |
55 | acl->a_entries[n].e_id = ACL_UNDEFINED_ID; | |
56 | break; | |
57 | ||
58 | case ACL_USER: | |
59 | case ACL_GROUP: | |
60 | value = (char *)value + sizeof(ext2_acl_entry); | |
61 | if ((char *)value > end) | |
62 | goto fail; | |
63 | acl->a_entries[n].e_id = | |
64 | le32_to_cpu(entry->e_id); | |
65 | break; | |
66 | ||
67 | default: | |
68 | goto fail; | |
69 | } | |
70 | } | |
71 | if (value != end) | |
72 | goto fail; | |
73 | return acl; | |
74 | ||
75 | fail: | |
76 | posix_acl_release(acl); | |
77 | return ERR_PTR(-EINVAL); | |
78 | } | |
79 | ||
80 | /* | |
81 | * Convert from in-memory to filesystem representation. | |
82 | */ | |
83 | static void * | |
84 | ext2_acl_to_disk(const struct posix_acl *acl, size_t *size) | |
85 | { | |
86 | ext2_acl_header *ext_acl; | |
87 | char *e; | |
88 | size_t n; | |
89 | ||
90 | *size = ext2_acl_size(acl->a_count); | |
91 | ext_acl = (ext2_acl_header *)kmalloc(sizeof(ext2_acl_header) + | |
92 | acl->a_count * sizeof(ext2_acl_entry), GFP_KERNEL); | |
93 | if (!ext_acl) | |
94 | return ERR_PTR(-ENOMEM); | |
95 | ext_acl->a_version = cpu_to_le32(EXT2_ACL_VERSION); | |
96 | e = (char *)ext_acl + sizeof(ext2_acl_header); | |
97 | for (n=0; n < acl->a_count; n++) { | |
98 | ext2_acl_entry *entry = (ext2_acl_entry *)e; | |
99 | entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag); | |
100 | entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm); | |
101 | switch(acl->a_entries[n].e_tag) { | |
102 | case ACL_USER: | |
103 | case ACL_GROUP: | |
104 | entry->e_id = | |
105 | cpu_to_le32(acl->a_entries[n].e_id); | |
106 | e += sizeof(ext2_acl_entry); | |
107 | break; | |
108 | ||
109 | case ACL_USER_OBJ: | |
110 | case ACL_GROUP_OBJ: | |
111 | case ACL_MASK: | |
112 | case ACL_OTHER: | |
113 | e += sizeof(ext2_acl_entry_short); | |
114 | break; | |
115 | ||
116 | default: | |
117 | goto fail; | |
118 | } | |
119 | } | |
120 | return (char *)ext_acl; | |
121 | ||
122 | fail: | |
123 | kfree(ext_acl); | |
124 | return ERR_PTR(-EINVAL); | |
125 | } | |
126 | ||
127 | static inline struct posix_acl * | |
128 | ext2_iget_acl(struct inode *inode, struct posix_acl **i_acl) | |
129 | { | |
130 | struct posix_acl *acl = EXT2_ACL_NOT_CACHED; | |
131 | ||
132 | spin_lock(&inode->i_lock); | |
133 | if (*i_acl != EXT2_ACL_NOT_CACHED) | |
134 | acl = posix_acl_dup(*i_acl); | |
135 | spin_unlock(&inode->i_lock); | |
136 | ||
137 | return acl; | |
138 | } | |
139 | ||
140 | static inline void | |
141 | ext2_iset_acl(struct inode *inode, struct posix_acl **i_acl, | |
142 | struct posix_acl *acl) | |
143 | { | |
144 | spin_lock(&inode->i_lock); | |
145 | if (*i_acl != EXT2_ACL_NOT_CACHED) | |
146 | posix_acl_release(*i_acl); | |
147 | *i_acl = posix_acl_dup(acl); | |
148 | spin_unlock(&inode->i_lock); | |
149 | } | |
150 | ||
151 | /* | |
152 | * inode->i_sem: don't care | |
153 | */ | |
154 | static struct posix_acl * | |
155 | ext2_get_acl(struct inode *inode, int type) | |
156 | { | |
157 | struct ext2_inode_info *ei = EXT2_I(inode); | |
158 | int name_index; | |
159 | char *value = NULL; | |
160 | struct posix_acl *acl; | |
161 | int retval; | |
162 | ||
163 | if (!test_opt(inode->i_sb, POSIX_ACL)) | |
164 | return NULL; | |
165 | ||
166 | switch(type) { | |
167 | case ACL_TYPE_ACCESS: | |
168 | acl = ext2_iget_acl(inode, &ei->i_acl); | |
169 | if (acl != EXT2_ACL_NOT_CACHED) | |
170 | return acl; | |
171 | name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS; | |
172 | break; | |
173 | ||
174 | case ACL_TYPE_DEFAULT: | |
175 | acl = ext2_iget_acl(inode, &ei->i_default_acl); | |
176 | if (acl != EXT2_ACL_NOT_CACHED) | |
177 | return acl; | |
178 | name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT; | |
179 | break; | |
180 | ||
181 | default: | |
182 | return ERR_PTR(-EINVAL); | |
183 | } | |
184 | retval = ext2_xattr_get(inode, name_index, "", NULL, 0); | |
185 | if (retval > 0) { | |
186 | value = kmalloc(retval, GFP_KERNEL); | |
187 | if (!value) | |
188 | return ERR_PTR(-ENOMEM); | |
189 | retval = ext2_xattr_get(inode, name_index, "", value, retval); | |
190 | } | |
191 | if (retval > 0) | |
192 | acl = ext2_acl_from_disk(value, retval); | |
193 | else if (retval == -ENODATA || retval == -ENOSYS) | |
194 | acl = NULL; | |
195 | else | |
196 | acl = ERR_PTR(retval); | |
197 | if (value) | |
198 | kfree(value); | |
199 | ||
200 | if (!IS_ERR(acl)) { | |
201 | switch(type) { | |
202 | case ACL_TYPE_ACCESS: | |
203 | ext2_iset_acl(inode, &ei->i_acl, acl); | |
204 | break; | |
205 | ||
206 | case ACL_TYPE_DEFAULT: | |
207 | ext2_iset_acl(inode, &ei->i_default_acl, acl); | |
208 | break; | |
209 | } | |
210 | } | |
211 | return acl; | |
212 | } | |
213 | ||
214 | /* | |
215 | * inode->i_sem: down | |
216 | */ | |
217 | static int | |
218 | ext2_set_acl(struct inode *inode, int type, struct posix_acl *acl) | |
219 | { | |
220 | struct ext2_inode_info *ei = EXT2_I(inode); | |
221 | int name_index; | |
222 | void *value = NULL; | |
223 | size_t size; | |
224 | int error; | |
225 | ||
226 | if (S_ISLNK(inode->i_mode)) | |
227 | return -EOPNOTSUPP; | |
228 | if (!test_opt(inode->i_sb, POSIX_ACL)) | |
229 | return 0; | |
230 | ||
231 | switch(type) { | |
232 | case ACL_TYPE_ACCESS: | |
233 | name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS; | |
234 | if (acl) { | |
235 | mode_t mode = inode->i_mode; | |
236 | error = posix_acl_equiv_mode(acl, &mode); | |
237 | if (error < 0) | |
238 | return error; | |
239 | else { | |
240 | inode->i_mode = mode; | |
241 | mark_inode_dirty(inode); | |
242 | if (error == 0) | |
243 | acl = NULL; | |
244 | } | |
245 | } | |
246 | break; | |
247 | ||
248 | case ACL_TYPE_DEFAULT: | |
249 | name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT; | |
250 | if (!S_ISDIR(inode->i_mode)) | |
251 | return acl ? -EACCES : 0; | |
252 | break; | |
253 | ||
254 | default: | |
255 | return -EINVAL; | |
256 | } | |
257 | if (acl) { | |
258 | value = ext2_acl_to_disk(acl, &size); | |
259 | if (IS_ERR(value)) | |
260 | return (int)PTR_ERR(value); | |
261 | } | |
262 | ||
263 | error = ext2_xattr_set(inode, name_index, "", value, size, 0); | |
264 | ||
265 | if (value) | |
266 | kfree(value); | |
267 | if (!error) { | |
268 | switch(type) { | |
269 | case ACL_TYPE_ACCESS: | |
270 | ext2_iset_acl(inode, &ei->i_acl, acl); | |
271 | break; | |
272 | ||
273 | case ACL_TYPE_DEFAULT: | |
274 | ext2_iset_acl(inode, &ei->i_default_acl, acl); | |
275 | break; | |
276 | } | |
277 | } | |
278 | return error; | |
279 | } | |
280 | ||
281 | static int | |
282 | ext2_check_acl(struct inode *inode, int mask) | |
283 | { | |
284 | struct posix_acl *acl = ext2_get_acl(inode, ACL_TYPE_ACCESS); | |
285 | ||
286 | if (acl) { | |
287 | int error = posix_acl_permission(inode, acl, mask); | |
288 | posix_acl_release(acl); | |
289 | return error; | |
290 | } | |
291 | ||
292 | return -EAGAIN; | |
293 | } | |
294 | ||
295 | int | |
296 | ext2_permission(struct inode *inode, int mask, struct nameidata *nd) | |
297 | { | |
298 | return generic_permission(inode, mask, ext2_check_acl); | |
299 | } | |
300 | ||
301 | /* | |
302 | * Initialize the ACLs of a new inode. Called from ext2_new_inode. | |
303 | * | |
304 | * dir->i_sem: down | |
305 | * inode->i_sem: up (access to inode is still exclusive) | |
306 | */ | |
307 | int | |
308 | ext2_init_acl(struct inode *inode, struct inode *dir) | |
309 | { | |
310 | struct posix_acl *acl = NULL; | |
311 | int error = 0; | |
312 | ||
313 | if (!S_ISLNK(inode->i_mode)) { | |
314 | if (test_opt(dir->i_sb, POSIX_ACL)) { | |
315 | acl = ext2_get_acl(dir, ACL_TYPE_DEFAULT); | |
316 | if (IS_ERR(acl)) | |
317 | return PTR_ERR(acl); | |
318 | } | |
319 | if (!acl) | |
320 | inode->i_mode &= ~current->fs->umask; | |
321 | } | |
322 | if (test_opt(inode->i_sb, POSIX_ACL) && acl) { | |
323 | struct posix_acl *clone; | |
324 | mode_t mode; | |
325 | ||
326 | if (S_ISDIR(inode->i_mode)) { | |
327 | error = ext2_set_acl(inode, ACL_TYPE_DEFAULT, acl); | |
328 | if (error) | |
329 | goto cleanup; | |
330 | } | |
331 | clone = posix_acl_clone(acl, GFP_KERNEL); | |
332 | error = -ENOMEM; | |
333 | if (!clone) | |
334 | goto cleanup; | |
335 | mode = inode->i_mode; | |
336 | error = posix_acl_create_masq(clone, &mode); | |
337 | if (error >= 0) { | |
338 | inode->i_mode = mode; | |
339 | if (error > 0) { | |
340 | /* This is an extended ACL */ | |
341 | error = ext2_set_acl(inode, | |
342 | ACL_TYPE_ACCESS, clone); | |
343 | } | |
344 | } | |
345 | posix_acl_release(clone); | |
346 | } | |
347 | cleanup: | |
348 | posix_acl_release(acl); | |
349 | return error; | |
350 | } | |
351 | ||
352 | /* | |
353 | * Does chmod for an inode that may have an Access Control List. The | |
354 | * inode->i_mode field must be updated to the desired value by the caller | |
355 | * before calling this function. | |
356 | * Returns 0 on success, or a negative error number. | |
357 | * | |
358 | * We change the ACL rather than storing some ACL entries in the file | |
359 | * mode permission bits (which would be more efficient), because that | |
360 | * would break once additional permissions (like ACL_APPEND, ACL_DELETE | |
361 | * for directories) are added. There are no more bits available in the | |
362 | * file mode. | |
363 | * | |
364 | * inode->i_sem: down | |
365 | */ | |
366 | int | |
367 | ext2_acl_chmod(struct inode *inode) | |
368 | { | |
369 | struct posix_acl *acl, *clone; | |
370 | int error; | |
371 | ||
372 | if (!test_opt(inode->i_sb, POSIX_ACL)) | |
373 | return 0; | |
374 | if (S_ISLNK(inode->i_mode)) | |
375 | return -EOPNOTSUPP; | |
376 | acl = ext2_get_acl(inode, ACL_TYPE_ACCESS); | |
377 | if (IS_ERR(acl) || !acl) | |
378 | return PTR_ERR(acl); | |
379 | clone = posix_acl_clone(acl, GFP_KERNEL); | |
380 | posix_acl_release(acl); | |
381 | if (!clone) | |
382 | return -ENOMEM; | |
383 | error = posix_acl_chmod_masq(clone, inode->i_mode); | |
384 | if (!error) | |
385 | error = ext2_set_acl(inode, ACL_TYPE_ACCESS, clone); | |
386 | posix_acl_release(clone); | |
387 | return error; | |
388 | } | |
389 | ||
390 | /* | |
391 | * Extended attribut handlers | |
392 | */ | |
393 | static size_t | |
394 | ext2_xattr_list_acl_access(struct inode *inode, char *list, size_t list_size, | |
395 | const char *name, size_t name_len) | |
396 | { | |
397 | const size_t size = sizeof(XATTR_NAME_ACL_ACCESS); | |
398 | ||
399 | if (!test_opt(inode->i_sb, POSIX_ACL)) | |
400 | return 0; | |
401 | if (list && size <= list_size) | |
402 | memcpy(list, XATTR_NAME_ACL_ACCESS, size); | |
403 | return size; | |
404 | } | |
405 | ||
406 | static size_t | |
407 | ext2_xattr_list_acl_default(struct inode *inode, char *list, size_t list_size, | |
408 | const char *name, size_t name_len) | |
409 | { | |
410 | const size_t size = sizeof(XATTR_NAME_ACL_DEFAULT); | |
411 | ||
412 | if (!test_opt(inode->i_sb, POSIX_ACL)) | |
413 | return 0; | |
414 | if (list && size <= list_size) | |
415 | memcpy(list, XATTR_NAME_ACL_DEFAULT, size); | |
416 | return size; | |
417 | } | |
418 | ||
419 | static int | |
420 | ext2_xattr_get_acl(struct inode *inode, int type, void *buffer, size_t size) | |
421 | { | |
422 | struct posix_acl *acl; | |
423 | int error; | |
424 | ||
425 | if (!test_opt(inode->i_sb, POSIX_ACL)) | |
426 | return -EOPNOTSUPP; | |
427 | ||
428 | acl = ext2_get_acl(inode, type); | |
429 | if (IS_ERR(acl)) | |
430 | return PTR_ERR(acl); | |
431 | if (acl == NULL) | |
432 | return -ENODATA; | |
433 | error = posix_acl_to_xattr(acl, buffer, size); | |
434 | posix_acl_release(acl); | |
435 | ||
436 | return error; | |
437 | } | |
438 | ||
439 | static int | |
440 | ext2_xattr_get_acl_access(struct inode *inode, const char *name, | |
441 | void *buffer, size_t size) | |
442 | { | |
443 | if (strcmp(name, "") != 0) | |
444 | return -EINVAL; | |
445 | return ext2_xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size); | |
446 | } | |
447 | ||
448 | static int | |
449 | ext2_xattr_get_acl_default(struct inode *inode, const char *name, | |
450 | void *buffer, size_t size) | |
451 | { | |
452 | if (strcmp(name, "") != 0) | |
453 | return -EINVAL; | |
454 | return ext2_xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size); | |
455 | } | |
456 | ||
457 | static int | |
458 | ext2_xattr_set_acl(struct inode *inode, int type, const void *value, | |
459 | size_t size) | |
460 | { | |
461 | struct posix_acl *acl; | |
462 | int error; | |
463 | ||
464 | if (!test_opt(inode->i_sb, POSIX_ACL)) | |
465 | return -EOPNOTSUPP; | |
466 | if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER)) | |
467 | return -EPERM; | |
468 | ||
469 | if (value) { | |
470 | acl = posix_acl_from_xattr(value, size); | |
471 | if (IS_ERR(acl)) | |
472 | return PTR_ERR(acl); | |
473 | else if (acl) { | |
474 | error = posix_acl_valid(acl); | |
475 | if (error) | |
476 | goto release_and_out; | |
477 | } | |
478 | } else | |
479 | acl = NULL; | |
480 | ||
481 | error = ext2_set_acl(inode, type, acl); | |
482 | ||
483 | release_and_out: | |
484 | posix_acl_release(acl); | |
485 | return error; | |
486 | } | |
487 | ||
488 | static int | |
489 | ext2_xattr_set_acl_access(struct inode *inode, const char *name, | |
490 | const void *value, size_t size, int flags) | |
491 | { | |
492 | if (strcmp(name, "") != 0) | |
493 | return -EINVAL; | |
494 | return ext2_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size); | |
495 | } | |
496 | ||
497 | static int | |
498 | ext2_xattr_set_acl_default(struct inode *inode, const char *name, | |
499 | const void *value, size_t size, int flags) | |
500 | { | |
501 | if (strcmp(name, "") != 0) | |
502 | return -EINVAL; | |
503 | return ext2_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size); | |
504 | } | |
505 | ||
506 | struct xattr_handler ext2_xattr_acl_access_handler = { | |
507 | .prefix = XATTR_NAME_ACL_ACCESS, | |
508 | .list = ext2_xattr_list_acl_access, | |
509 | .get = ext2_xattr_get_acl_access, | |
510 | .set = ext2_xattr_set_acl_access, | |
511 | }; | |
512 | ||
513 | struct xattr_handler ext2_xattr_acl_default_handler = { | |
514 | .prefix = XATTR_NAME_ACL_DEFAULT, | |
515 | .list = ext2_xattr_list_acl_default, | |
516 | .get = ext2_xattr_get_acl_default, | |
517 | .set = ext2_xattr_set_acl_default, | |
518 | }; |