blob: 213148c36ebef341ae8c460af7cd2d9c095a5d3b [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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 */
18static struct posix_acl *
19ext2_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
75fail:
76 posix_acl_release(acl);
77 return ERR_PTR(-EINVAL);
78}
79
80/*
81 * Convert from in-memory to filesystem representation.
82 */
83static void *
84ext2_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
122fail:
123 kfree(ext_acl);
124 return ERR_PTR(-EINVAL);
125}
126
127static inline struct posix_acl *
128ext2_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
140static inline void
141ext2_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 */
154static struct posix_acl *
155ext2_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 */
217static int
218ext2_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
281static int
282ext2_check_acl(struct inode *inode, int mask)
283{
284 struct posix_acl *acl = ext2_get_acl(inode, ACL_TYPE_ACCESS);
285
akpm@osdl.orge4930732005-04-16 15:24:00 -0700286 if (IS_ERR(acl))
287 return PTR_ERR(acl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288 if (acl) {
289 int error = posix_acl_permission(inode, acl, mask);
290 posix_acl_release(acl);
291 return error;
292 }
293
294 return -EAGAIN;
295}
296
297int
298ext2_permission(struct inode *inode, int mask, struct nameidata *nd)
299{
300 return generic_permission(inode, mask, ext2_check_acl);
301}
302
303/*
304 * Initialize the ACLs of a new inode. Called from ext2_new_inode.
305 *
306 * dir->i_sem: down
307 * inode->i_sem: up (access to inode is still exclusive)
308 */
309int
310ext2_init_acl(struct inode *inode, struct inode *dir)
311{
312 struct posix_acl *acl = NULL;
313 int error = 0;
314
315 if (!S_ISLNK(inode->i_mode)) {
316 if (test_opt(dir->i_sb, POSIX_ACL)) {
317 acl = ext2_get_acl(dir, ACL_TYPE_DEFAULT);
318 if (IS_ERR(acl))
319 return PTR_ERR(acl);
320 }
321 if (!acl)
322 inode->i_mode &= ~current->fs->umask;
323 }
324 if (test_opt(inode->i_sb, POSIX_ACL) && acl) {
325 struct posix_acl *clone;
326 mode_t mode;
327
328 if (S_ISDIR(inode->i_mode)) {
329 error = ext2_set_acl(inode, ACL_TYPE_DEFAULT, acl);
330 if (error)
331 goto cleanup;
332 }
333 clone = posix_acl_clone(acl, GFP_KERNEL);
334 error = -ENOMEM;
335 if (!clone)
336 goto cleanup;
337 mode = inode->i_mode;
338 error = posix_acl_create_masq(clone, &mode);
339 if (error >= 0) {
340 inode->i_mode = mode;
341 if (error > 0) {
342 /* This is an extended ACL */
343 error = ext2_set_acl(inode,
344 ACL_TYPE_ACCESS, clone);
345 }
346 }
347 posix_acl_release(clone);
348 }
349cleanup:
350 posix_acl_release(acl);
351 return error;
352}
353
354/*
355 * Does chmod for an inode that may have an Access Control List. The
356 * inode->i_mode field must be updated to the desired value by the caller
357 * before calling this function.
358 * Returns 0 on success, or a negative error number.
359 *
360 * We change the ACL rather than storing some ACL entries in the file
361 * mode permission bits (which would be more efficient), because that
362 * would break once additional permissions (like ACL_APPEND, ACL_DELETE
363 * for directories) are added. There are no more bits available in the
364 * file mode.
365 *
366 * inode->i_sem: down
367 */
368int
369ext2_acl_chmod(struct inode *inode)
370{
371 struct posix_acl *acl, *clone;
372 int error;
373
374 if (!test_opt(inode->i_sb, POSIX_ACL))
375 return 0;
376 if (S_ISLNK(inode->i_mode))
377 return -EOPNOTSUPP;
378 acl = ext2_get_acl(inode, ACL_TYPE_ACCESS);
379 if (IS_ERR(acl) || !acl)
380 return PTR_ERR(acl);
381 clone = posix_acl_clone(acl, GFP_KERNEL);
382 posix_acl_release(acl);
383 if (!clone)
384 return -ENOMEM;
385 error = posix_acl_chmod_masq(clone, inode->i_mode);
386 if (!error)
387 error = ext2_set_acl(inode, ACL_TYPE_ACCESS, clone);
388 posix_acl_release(clone);
389 return error;
390}
391
392/*
393 * Extended attribut handlers
394 */
395static size_t
396ext2_xattr_list_acl_access(struct inode *inode, char *list, size_t list_size,
397 const char *name, size_t name_len)
398{
Christoph Hellwig9a59f452005-06-23 00:10:19 -0700399 const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400
401 if (!test_opt(inode->i_sb, POSIX_ACL))
402 return 0;
403 if (list && size <= list_size)
Christoph Hellwig9a59f452005-06-23 00:10:19 -0700404 memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405 return size;
406}
407
408static size_t
409ext2_xattr_list_acl_default(struct inode *inode, char *list, size_t list_size,
410 const char *name, size_t name_len)
411{
Christoph Hellwig9a59f452005-06-23 00:10:19 -0700412 const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413
414 if (!test_opt(inode->i_sb, POSIX_ACL))
415 return 0;
416 if (list && size <= list_size)
Christoph Hellwig9a59f452005-06-23 00:10:19 -0700417 memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418 return size;
419}
420
421static int
422ext2_xattr_get_acl(struct inode *inode, int type, void *buffer, size_t size)
423{
424 struct posix_acl *acl;
425 int error;
426
427 if (!test_opt(inode->i_sb, POSIX_ACL))
428 return -EOPNOTSUPP;
429
430 acl = ext2_get_acl(inode, type);
431 if (IS_ERR(acl))
432 return PTR_ERR(acl);
433 if (acl == NULL)
434 return -ENODATA;
435 error = posix_acl_to_xattr(acl, buffer, size);
436 posix_acl_release(acl);
437
438 return error;
439}
440
441static int
442ext2_xattr_get_acl_access(struct inode *inode, const char *name,
443 void *buffer, size_t size)
444{
445 if (strcmp(name, "") != 0)
446 return -EINVAL;
447 return ext2_xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
448}
449
450static int
451ext2_xattr_get_acl_default(struct inode *inode, const char *name,
452 void *buffer, size_t size)
453{
454 if (strcmp(name, "") != 0)
455 return -EINVAL;
456 return ext2_xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
457}
458
459static int
460ext2_xattr_set_acl(struct inode *inode, int type, const void *value,
461 size_t size)
462{
463 struct posix_acl *acl;
464 int error;
465
466 if (!test_opt(inode->i_sb, POSIX_ACL))
467 return -EOPNOTSUPP;
468 if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
469 return -EPERM;
470
471 if (value) {
472 acl = posix_acl_from_xattr(value, size);
473 if (IS_ERR(acl))
474 return PTR_ERR(acl);
475 else if (acl) {
476 error = posix_acl_valid(acl);
477 if (error)
478 goto release_and_out;
479 }
480 } else
481 acl = NULL;
482
483 error = ext2_set_acl(inode, type, acl);
484
485release_and_out:
486 posix_acl_release(acl);
487 return error;
488}
489
490static int
491ext2_xattr_set_acl_access(struct inode *inode, const char *name,
492 const void *value, size_t size, int flags)
493{
494 if (strcmp(name, "") != 0)
495 return -EINVAL;
496 return ext2_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
497}
498
499static int
500ext2_xattr_set_acl_default(struct inode *inode, const char *name,
501 const void *value, size_t size, int flags)
502{
503 if (strcmp(name, "") != 0)
504 return -EINVAL;
505 return ext2_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
506}
507
508struct xattr_handler ext2_xattr_acl_access_handler = {
Christoph Hellwig9a59f452005-06-23 00:10:19 -0700509 .prefix = POSIX_ACL_XATTR_ACCESS,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510 .list = ext2_xattr_list_acl_access,
511 .get = ext2_xattr_get_acl_access,
512 .set = ext2_xattr_set_acl_access,
513};
514
515struct xattr_handler ext2_xattr_acl_default_handler = {
Christoph Hellwig9a59f452005-06-23 00:10:19 -0700516 .prefix = POSIX_ACL_XATTR_DEFAULT,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700517 .list = ext2_xattr_list_acl_default,
518 .get = ext2_xattr_get_acl_default,
519 .set = ext2_xattr_set_acl_default,
520};