ia64/linux-2.6.18-xen.hg

view fs/ext3/acl.c @ 524:7f8b544237bf

netfront: Allow netfront in domain 0.

This is useful if your physical network device is in a utility domain.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
author Keir Fraser <keir.fraser@citrix.com>
date Tue Apr 15 15:18:58 2008 +0100 (2008-04-15)
parents 831230e53067
children
line source
1 /*
2 * linux/fs/ext3/acl.c
3 *
4 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
5 */
7 #include <linux/init.h>
8 #include <linux/sched.h>
9 #include <linux/slab.h>
10 #include <linux/capability.h>
11 #include <linux/fs.h>
12 #include <linux/ext3_jbd.h>
13 #include <linux/ext3_fs.h>
14 #include "xattr.h"
15 #include "acl.h"
17 /*
18 * Convert from filesystem to in-memory representation.
19 */
20 static struct posix_acl *
21 ext3_acl_from_disk(const void *value, size_t size)
22 {
23 const char *end = (char *)value + size;
24 int n, count;
25 struct posix_acl *acl;
27 if (!value)
28 return NULL;
29 if (size < sizeof(ext3_acl_header))
30 return ERR_PTR(-EINVAL);
31 if (((ext3_acl_header *)value)->a_version !=
32 cpu_to_le32(EXT3_ACL_VERSION))
33 return ERR_PTR(-EINVAL);
34 value = (char *)value + sizeof(ext3_acl_header);
35 count = ext3_acl_count(size);
36 if (count < 0)
37 return ERR_PTR(-EINVAL);
38 if (count == 0)
39 return NULL;
40 acl = posix_acl_alloc(count, GFP_KERNEL);
41 if (!acl)
42 return ERR_PTR(-ENOMEM);
43 for (n=0; n < count; n++) {
44 ext3_acl_entry *entry =
45 (ext3_acl_entry *)value;
46 if ((char *)value + sizeof(ext3_acl_entry_short) > end)
47 goto fail;
48 acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
49 acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
50 switch(acl->a_entries[n].e_tag) {
51 case ACL_USER_OBJ:
52 case ACL_GROUP_OBJ:
53 case ACL_MASK:
54 case ACL_OTHER:
55 value = (char *)value +
56 sizeof(ext3_acl_entry_short);
57 acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
58 break;
60 case ACL_USER:
61 case ACL_GROUP:
62 value = (char *)value + sizeof(ext3_acl_entry);
63 if ((char *)value > end)
64 goto fail;
65 acl->a_entries[n].e_id =
66 le32_to_cpu(entry->e_id);
67 break;
69 default:
70 goto fail;
71 }
72 }
73 if (value != end)
74 goto fail;
75 return acl;
77 fail:
78 posix_acl_release(acl);
79 return ERR_PTR(-EINVAL);
80 }
82 /*
83 * Convert from in-memory to filesystem representation.
84 */
85 static void *
86 ext3_acl_to_disk(const struct posix_acl *acl, size_t *size)
87 {
88 ext3_acl_header *ext_acl;
89 char *e;
90 size_t n;
92 *size = ext3_acl_size(acl->a_count);
93 ext_acl = (ext3_acl_header *)kmalloc(sizeof(ext3_acl_header) +
94 acl->a_count * sizeof(ext3_acl_entry), GFP_KERNEL);
95 if (!ext_acl)
96 return ERR_PTR(-ENOMEM);
97 ext_acl->a_version = cpu_to_le32(EXT3_ACL_VERSION);
98 e = (char *)ext_acl + sizeof(ext3_acl_header);
99 for (n=0; n < acl->a_count; n++) {
100 ext3_acl_entry *entry = (ext3_acl_entry *)e;
101 entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
102 entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
103 switch(acl->a_entries[n].e_tag) {
104 case ACL_USER:
105 case ACL_GROUP:
106 entry->e_id =
107 cpu_to_le32(acl->a_entries[n].e_id);
108 e += sizeof(ext3_acl_entry);
109 break;
111 case ACL_USER_OBJ:
112 case ACL_GROUP_OBJ:
113 case ACL_MASK:
114 case ACL_OTHER:
115 e += sizeof(ext3_acl_entry_short);
116 break;
118 default:
119 goto fail;
120 }
121 }
122 return (char *)ext_acl;
124 fail:
125 kfree(ext_acl);
126 return ERR_PTR(-EINVAL);
127 }
129 static inline struct posix_acl *
130 ext3_iget_acl(struct inode *inode, struct posix_acl **i_acl)
131 {
132 struct posix_acl *acl = EXT3_ACL_NOT_CACHED;
134 spin_lock(&inode->i_lock);
135 if (*i_acl != EXT3_ACL_NOT_CACHED)
136 acl = posix_acl_dup(*i_acl);
137 spin_unlock(&inode->i_lock);
139 return acl;
140 }
142 static inline void
143 ext3_iset_acl(struct inode *inode, struct posix_acl **i_acl,
144 struct posix_acl *acl)
145 {
146 spin_lock(&inode->i_lock);
147 if (*i_acl != EXT3_ACL_NOT_CACHED)
148 posix_acl_release(*i_acl);
149 *i_acl = posix_acl_dup(acl);
150 spin_unlock(&inode->i_lock);
151 }
153 /*
154 * Inode operation get_posix_acl().
155 *
156 * inode->i_mutex: don't care
157 */
158 static struct posix_acl *
159 ext3_get_acl(struct inode *inode, int type)
160 {
161 struct ext3_inode_info *ei = EXT3_I(inode);
162 int name_index;
163 char *value = NULL;
164 struct posix_acl *acl;
165 int retval;
167 if (!test_opt(inode->i_sb, POSIX_ACL))
168 return NULL;
170 switch(type) {
171 case ACL_TYPE_ACCESS:
172 acl = ext3_iget_acl(inode, &ei->i_acl);
173 if (acl != EXT3_ACL_NOT_CACHED)
174 return acl;
175 name_index = EXT3_XATTR_INDEX_POSIX_ACL_ACCESS;
176 break;
178 case ACL_TYPE_DEFAULT:
179 acl = ext3_iget_acl(inode, &ei->i_default_acl);
180 if (acl != EXT3_ACL_NOT_CACHED)
181 return acl;
182 name_index = EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT;
183 break;
185 default:
186 return ERR_PTR(-EINVAL);
187 }
188 retval = ext3_xattr_get(inode, name_index, "", NULL, 0);
189 if (retval > 0) {
190 value = kmalloc(retval, GFP_KERNEL);
191 if (!value)
192 return ERR_PTR(-ENOMEM);
193 retval = ext3_xattr_get(inode, name_index, "", value, retval);
194 }
195 if (retval > 0)
196 acl = ext3_acl_from_disk(value, retval);
197 else if (retval == -ENODATA || retval == -ENOSYS)
198 acl = NULL;
199 else
200 acl = ERR_PTR(retval);
201 kfree(value);
203 if (!IS_ERR(acl)) {
204 switch(type) {
205 case ACL_TYPE_ACCESS:
206 ext3_iset_acl(inode, &ei->i_acl, acl);
207 break;
209 case ACL_TYPE_DEFAULT:
210 ext3_iset_acl(inode, &ei->i_default_acl, acl);
211 break;
212 }
213 }
214 return acl;
215 }
217 /*
218 * Set the access or default ACL of an inode.
219 *
220 * inode->i_mutex: down unless called from ext3_new_inode
221 */
222 static int
223 ext3_set_acl(handle_t *handle, struct inode *inode, int type,
224 struct posix_acl *acl)
225 {
226 struct ext3_inode_info *ei = EXT3_I(inode);
227 int name_index;
228 void *value = NULL;
229 size_t size = 0;
230 int error;
232 if (S_ISLNK(inode->i_mode))
233 return -EOPNOTSUPP;
235 switch(type) {
236 case ACL_TYPE_ACCESS:
237 name_index = EXT3_XATTR_INDEX_POSIX_ACL_ACCESS;
238 if (acl) {
239 mode_t mode = inode->i_mode;
240 error = posix_acl_equiv_mode(acl, &mode);
241 if (error < 0)
242 return error;
243 else {
244 inode->i_mode = mode;
245 ext3_mark_inode_dirty(handle, inode);
246 if (error == 0)
247 acl = NULL;
248 }
249 }
250 break;
252 case ACL_TYPE_DEFAULT:
253 name_index = EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT;
254 if (!S_ISDIR(inode->i_mode))
255 return acl ? -EACCES : 0;
256 break;
258 default:
259 return -EINVAL;
260 }
261 if (acl) {
262 value = ext3_acl_to_disk(acl, &size);
263 if (IS_ERR(value))
264 return (int)PTR_ERR(value);
265 }
267 error = ext3_xattr_set_handle(handle, inode, name_index, "",
268 value, size, 0);
270 kfree(value);
271 if (!error) {
272 switch(type) {
273 case ACL_TYPE_ACCESS:
274 ext3_iset_acl(inode, &ei->i_acl, acl);
275 break;
277 case ACL_TYPE_DEFAULT:
278 ext3_iset_acl(inode, &ei->i_default_acl, acl);
279 break;
280 }
281 }
282 return error;
283 }
285 static int
286 ext3_check_acl(struct inode *inode, int mask)
287 {
288 struct posix_acl *acl = ext3_get_acl(inode, ACL_TYPE_ACCESS);
290 if (IS_ERR(acl))
291 return PTR_ERR(acl);
292 if (acl) {
293 int error = posix_acl_permission(inode, acl, mask);
294 posix_acl_release(acl);
295 return error;
296 }
298 return -EAGAIN;
299 }
301 int
302 ext3_permission(struct inode *inode, int mask, struct nameidata *nd)
303 {
304 return generic_permission(inode, mask, ext3_check_acl);
305 }
307 /*
308 * Initialize the ACLs of a new inode. Called from ext3_new_inode.
309 *
310 * dir->i_mutex: down
311 * inode->i_mutex: up (access to inode is still exclusive)
312 */
313 int
314 ext3_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)
315 {
316 struct posix_acl *acl = NULL;
317 int error = 0;
319 if (!S_ISLNK(inode->i_mode)) {
320 if (test_opt(dir->i_sb, POSIX_ACL)) {
321 acl = ext3_get_acl(dir, ACL_TYPE_DEFAULT);
322 if (IS_ERR(acl))
323 return PTR_ERR(acl);
324 }
325 if (!acl)
326 inode->i_mode &= ~current->fs->umask;
327 }
328 if (test_opt(inode->i_sb, POSIX_ACL) && acl) {
329 struct posix_acl *clone;
330 mode_t mode;
332 if (S_ISDIR(inode->i_mode)) {
333 error = ext3_set_acl(handle, inode,
334 ACL_TYPE_DEFAULT, acl);
335 if (error)
336 goto cleanup;
337 }
338 clone = posix_acl_clone(acl, GFP_KERNEL);
339 error = -ENOMEM;
340 if (!clone)
341 goto cleanup;
343 mode = inode->i_mode;
344 error = posix_acl_create_masq(clone, &mode);
345 if (error >= 0) {
346 inode->i_mode = mode;
347 if (error > 0) {
348 /* This is an extended ACL */
349 error = ext3_set_acl(handle, inode,
350 ACL_TYPE_ACCESS, clone);
351 }
352 }
353 posix_acl_release(clone);
354 }
355 cleanup:
356 posix_acl_release(acl);
357 return error;
358 }
360 /*
361 * Does chmod for an inode that may have an Access Control List. The
362 * inode->i_mode field must be updated to the desired value by the caller
363 * before calling this function.
364 * Returns 0 on success, or a negative error number.
365 *
366 * We change the ACL rather than storing some ACL entries in the file
367 * mode permission bits (which would be more efficient), because that
368 * would break once additional permissions (like ACL_APPEND, ACL_DELETE
369 * for directories) are added. There are no more bits available in the
370 * file mode.
371 *
372 * inode->i_mutex: down
373 */
374 int
375 ext3_acl_chmod(struct inode *inode)
376 {
377 struct posix_acl *acl, *clone;
378 int error;
380 if (S_ISLNK(inode->i_mode))
381 return -EOPNOTSUPP;
382 if (!test_opt(inode->i_sb, POSIX_ACL))
383 return 0;
384 acl = ext3_get_acl(inode, ACL_TYPE_ACCESS);
385 if (IS_ERR(acl) || !acl)
386 return PTR_ERR(acl);
387 clone = posix_acl_clone(acl, GFP_KERNEL);
388 posix_acl_release(acl);
389 if (!clone)
390 return -ENOMEM;
391 error = posix_acl_chmod_masq(clone, inode->i_mode);
392 if (!error) {
393 handle_t *handle;
394 int retries = 0;
396 retry:
397 handle = ext3_journal_start(inode,
398 EXT3_DATA_TRANS_BLOCKS(inode->i_sb));
399 if (IS_ERR(handle)) {
400 error = PTR_ERR(handle);
401 ext3_std_error(inode->i_sb, error);
402 goto out;
403 }
404 error = ext3_set_acl(handle, inode, ACL_TYPE_ACCESS, clone);
405 ext3_journal_stop(handle);
406 if (error == -ENOSPC &&
407 ext3_should_retry_alloc(inode->i_sb, &retries))
408 goto retry;
409 }
410 out:
411 posix_acl_release(clone);
412 return error;
413 }
415 /*
416 * Extended attribute handlers
417 */
418 static size_t
419 ext3_xattr_list_acl_access(struct inode *inode, char *list, size_t list_len,
420 const char *name, size_t name_len)
421 {
422 const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
424 if (!test_opt(inode->i_sb, POSIX_ACL))
425 return 0;
426 if (list && size <= list_len)
427 memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
428 return size;
429 }
431 static size_t
432 ext3_xattr_list_acl_default(struct inode *inode, char *list, size_t list_len,
433 const char *name, size_t name_len)
434 {
435 const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
437 if (!test_opt(inode->i_sb, POSIX_ACL))
438 return 0;
439 if (list && size <= list_len)
440 memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
441 return size;
442 }
444 static int
445 ext3_xattr_get_acl(struct inode *inode, int type, void *buffer, size_t size)
446 {
447 struct posix_acl *acl;
448 int error;
450 if (!test_opt(inode->i_sb, POSIX_ACL))
451 return -EOPNOTSUPP;
453 acl = ext3_get_acl(inode, type);
454 if (IS_ERR(acl))
455 return PTR_ERR(acl);
456 if (acl == NULL)
457 return -ENODATA;
458 error = posix_acl_to_xattr(acl, buffer, size);
459 posix_acl_release(acl);
461 return error;
462 }
464 static int
465 ext3_xattr_get_acl_access(struct inode *inode, const char *name,
466 void *buffer, size_t size)
467 {
468 if (strcmp(name, "") != 0)
469 return -EINVAL;
470 return ext3_xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
471 }
473 static int
474 ext3_xattr_get_acl_default(struct inode *inode, const char *name,
475 void *buffer, size_t size)
476 {
477 if (strcmp(name, "") != 0)
478 return -EINVAL;
479 return ext3_xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
480 }
482 static int
483 ext3_xattr_set_acl(struct inode *inode, int type, const void *value,
484 size_t size)
485 {
486 handle_t *handle;
487 struct posix_acl *acl;
488 int error, retries = 0;
490 if (!test_opt(inode->i_sb, POSIX_ACL))
491 return -EOPNOTSUPP;
492 if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
493 return -EPERM;
495 if (value) {
496 acl = posix_acl_from_xattr(value, size);
497 if (IS_ERR(acl))
498 return PTR_ERR(acl);
499 else if (acl) {
500 error = posix_acl_valid(acl);
501 if (error)
502 goto release_and_out;
503 }
504 } else
505 acl = NULL;
507 retry:
508 handle = ext3_journal_start(inode, EXT3_DATA_TRANS_BLOCKS(inode->i_sb));
509 if (IS_ERR(handle))
510 return PTR_ERR(handle);
511 error = ext3_set_acl(handle, inode, type, acl);
512 ext3_journal_stop(handle);
513 if (error == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
514 goto retry;
516 release_and_out:
517 posix_acl_release(acl);
518 return error;
519 }
521 static int
522 ext3_xattr_set_acl_access(struct inode *inode, const char *name,
523 const void *value, size_t size, int flags)
524 {
525 if (strcmp(name, "") != 0)
526 return -EINVAL;
527 return ext3_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
528 }
530 static int
531 ext3_xattr_set_acl_default(struct inode *inode, const char *name,
532 const void *value, size_t size, int flags)
533 {
534 if (strcmp(name, "") != 0)
535 return -EINVAL;
536 return ext3_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
537 }
539 struct xattr_handler ext3_xattr_acl_access_handler = {
540 .prefix = POSIX_ACL_XATTR_ACCESS,
541 .list = ext3_xattr_list_acl_access,
542 .get = ext3_xattr_get_acl_access,
543 .set = ext3_xattr_set_acl_access,
544 };
546 struct xattr_handler ext3_xattr_acl_default_handler = {
547 .prefix = POSIX_ACL_XATTR_DEFAULT,
548 .list = ext3_xattr_list_acl_default,
549 .get = ext3_xattr_get_acl_default,
550 .set = ext3_xattr_set_acl_default,
551 };