Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[deliverable/linux.git] / fs / ext4 / acl.c
CommitLineData
ac27a0ec 1/*
617ba13b 2 * linux/fs/ext4/acl.c
ac27a0ec
DK
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/capability.h>
11#include <linux/fs.h>
3dcf5451
CH
12#include "ext4_jbd2.h"
13#include "ext4.h"
ac27a0ec
DK
14#include "xattr.h"
15#include "acl.h"
16
17/*
18 * Convert from filesystem to in-memory representation.
19 */
20static struct posix_acl *
617ba13b 21ext4_acl_from_disk(const void *value, size_t size)
ac27a0ec
DK
22{
23 const char *end = (char *)value + size;
24 int n, count;
25 struct posix_acl *acl;
26
27 if (!value)
28 return NULL;
617ba13b 29 if (size < sizeof(ext4_acl_header))
ac27a0ec 30 return ERR_PTR(-EINVAL);
617ba13b
MC
31 if (((ext4_acl_header *)value)->a_version !=
32 cpu_to_le32(EXT4_ACL_VERSION))
ac27a0ec 33 return ERR_PTR(-EINVAL);
617ba13b
MC
34 value = (char *)value + sizeof(ext4_acl_header);
35 count = ext4_acl_count(size);
ac27a0ec
DK
36 if (count < 0)
37 return ERR_PTR(-EINVAL);
38 if (count == 0)
39 return NULL;
216553c4 40 acl = posix_acl_alloc(count, GFP_NOFS);
ac27a0ec
DK
41 if (!acl)
42 return ERR_PTR(-ENOMEM);
2b2d6d01 43 for (n = 0; n < count; n++) {
617ba13b
MC
44 ext4_acl_entry *entry =
45 (ext4_acl_entry *)value;
46 if ((char *)value + sizeof(ext4_acl_entry_short) > end)
ac27a0ec
DK
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);
2b2d6d01
TT
50
51 switch (acl->a_entries[n].e_tag) {
52 case ACL_USER_OBJ:
53 case ACL_GROUP_OBJ:
54 case ACL_MASK:
55 case ACL_OTHER:
56 value = (char *)value +
57 sizeof(ext4_acl_entry_short);
58 acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
59 break;
60
61 case ACL_USER:
62 case ACL_GROUP:
63 value = (char *)value + sizeof(ext4_acl_entry);
64 if ((char *)value > end)
ac27a0ec 65 goto fail;
2b2d6d01
TT
66 acl->a_entries[n].e_id =
67 le32_to_cpu(entry->e_id);
68 break;
69
70 default:
71 goto fail;
ac27a0ec
DK
72 }
73 }
74 if (value != end)
75 goto fail;
76 return acl;
77
78fail:
79 posix_acl_release(acl);
80 return ERR_PTR(-EINVAL);
81}
82
83/*
84 * Convert from in-memory to filesystem representation.
85 */
86static void *
617ba13b 87ext4_acl_to_disk(const struct posix_acl *acl, size_t *size)
ac27a0ec 88{
617ba13b 89 ext4_acl_header *ext_acl;
ac27a0ec
DK
90 char *e;
91 size_t n;
92
617ba13b
MC
93 *size = ext4_acl_size(acl->a_count);
94 ext_acl = kmalloc(sizeof(ext4_acl_header) + acl->a_count *
216553c4 95 sizeof(ext4_acl_entry), GFP_NOFS);
ac27a0ec
DK
96 if (!ext_acl)
97 return ERR_PTR(-ENOMEM);
617ba13b
MC
98 ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION);
99 e = (char *)ext_acl + sizeof(ext4_acl_header);
2b2d6d01 100 for (n = 0; n < acl->a_count; n++) {
617ba13b 101 ext4_acl_entry *entry = (ext4_acl_entry *)e;
ac27a0ec
DK
102 entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
103 entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
2b2d6d01
TT
104 switch (acl->a_entries[n].e_tag) {
105 case ACL_USER:
106 case ACL_GROUP:
107 entry->e_id = cpu_to_le32(acl->a_entries[n].e_id);
108 e += sizeof(ext4_acl_entry);
109 break;
110
111 case ACL_USER_OBJ:
112 case ACL_GROUP_OBJ:
113 case ACL_MASK:
114 case ACL_OTHER:
115 e += sizeof(ext4_acl_entry_short);
116 break;
117
118 default:
119 goto fail;
ac27a0ec
DK
120 }
121 }
122 return (char *)ext_acl;
123
124fail:
125 kfree(ext_acl);
126 return ERR_PTR(-EINVAL);
127}
128
ac27a0ec
DK
129/*
130 * Inode operation get_posix_acl().
131 *
132 * inode->i_mutex: don't care
133 */
134static struct posix_acl *
617ba13b 135ext4_get_acl(struct inode *inode, int type)
ac27a0ec 136{
ac27a0ec
DK
137 int name_index;
138 char *value = NULL;
139 struct posix_acl *acl;
140 int retval;
141
142 if (!test_opt(inode->i_sb, POSIX_ACL))
143 return NULL;
144
073aaa1b
AV
145 acl = get_cached_acl(inode, type);
146 if (acl != ACL_NOT_CACHED)
147 return acl;
148
2b2d6d01
TT
149 switch (type) {
150 case ACL_TYPE_ACCESS:
2b2d6d01
TT
151 name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
152 break;
2b2d6d01 153 case ACL_TYPE_DEFAULT:
2b2d6d01
TT
154 name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
155 break;
2b2d6d01 156 default:
073aaa1b 157 BUG();
ac27a0ec 158 }
617ba13b 159 retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
ac27a0ec 160 if (retval > 0) {
216553c4 161 value = kmalloc(retval, GFP_NOFS);
ac27a0ec
DK
162 if (!value)
163 return ERR_PTR(-ENOMEM);
617ba13b 164 retval = ext4_xattr_get(inode, name_index, "", value, retval);
ac27a0ec
DK
165 }
166 if (retval > 0)
617ba13b 167 acl = ext4_acl_from_disk(value, retval);
ac27a0ec
DK
168 else if (retval == -ENODATA || retval == -ENOSYS)
169 acl = NULL;
170 else
171 acl = ERR_PTR(retval);
172 kfree(value);
173
073aaa1b
AV
174 if (!IS_ERR(acl))
175 set_cached_acl(inode, type, acl);
2b2d6d01 176
ac27a0ec
DK
177 return acl;
178}
179
180/*
181 * Set the access or default ACL of an inode.
182 *
617ba13b 183 * inode->i_mutex: down unless called from ext4_new_inode
ac27a0ec
DK
184 */
185static int
617ba13b 186ext4_set_acl(handle_t *handle, struct inode *inode, int type,
ac27a0ec
DK
187 struct posix_acl *acl)
188{
ac27a0ec
DK
189 int name_index;
190 void *value = NULL;
191 size_t size = 0;
192 int error;
193
194 if (S_ISLNK(inode->i_mode))
195 return -EOPNOTSUPP;
196
2b2d6d01
TT
197 switch (type) {
198 case ACL_TYPE_ACCESS:
199 name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
200 if (acl) {
201 mode_t mode = inode->i_mode;
202 error = posix_acl_equiv_mode(acl, &mode);
203 if (error < 0)
204 return error;
205 else {
206 inode->i_mode = mode;
207 ext4_mark_inode_dirty(handle, inode);
208 if (error == 0)
209 acl = NULL;
ac27a0ec 210 }
2b2d6d01
TT
211 }
212 break;
ac27a0ec 213
2b2d6d01
TT
214 case ACL_TYPE_DEFAULT:
215 name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
216 if (!S_ISDIR(inode->i_mode))
217 return acl ? -EACCES : 0;
218 break;
ac27a0ec 219
2b2d6d01
TT
220 default:
221 return -EINVAL;
ac27a0ec
DK
222 }
223 if (acl) {
617ba13b 224 value = ext4_acl_to_disk(acl, &size);
ac27a0ec
DK
225 if (IS_ERR(value))
226 return (int)PTR_ERR(value);
227 }
228
617ba13b 229 error = ext4_xattr_set_handle(handle, inode, name_index, "",
ac27a0ec
DK
230 value, size, 0);
231
232 kfree(value);
073aaa1b
AV
233 if (!error)
234 set_cached_acl(inode, type, acl);
2b2d6d01 235
ac27a0ec
DK
236 return error;
237}
238
239static int
617ba13b 240ext4_check_acl(struct inode *inode, int mask)
ac27a0ec 241{
617ba13b 242 struct posix_acl *acl = ext4_get_acl(inode, ACL_TYPE_ACCESS);
ac27a0ec
DK
243
244 if (IS_ERR(acl))
245 return PTR_ERR(acl);
246 if (acl) {
247 int error = posix_acl_permission(inode, acl, mask);
248 posix_acl_release(acl);
249 return error;
250 }
251
252 return -EAGAIN;
253}
254
255int
e6305c43 256ext4_permission(struct inode *inode, int mask)
ac27a0ec 257{
617ba13b 258 return generic_permission(inode, mask, ext4_check_acl);
ac27a0ec
DK
259}
260
261/*
617ba13b 262 * Initialize the ACLs of a new inode. Called from ext4_new_inode.
ac27a0ec
DK
263 *
264 * dir->i_mutex: down
265 * inode->i_mutex: up (access to inode is still exclusive)
266 */
267int
617ba13b 268ext4_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)
ac27a0ec
DK
269{
270 struct posix_acl *acl = NULL;
271 int error = 0;
272
273 if (!S_ISLNK(inode->i_mode)) {
274 if (test_opt(dir->i_sb, POSIX_ACL)) {
617ba13b 275 acl = ext4_get_acl(dir, ACL_TYPE_DEFAULT);
ac27a0ec
DK
276 if (IS_ERR(acl))
277 return PTR_ERR(acl);
278 }
279 if (!acl)
ce3b0f8d 280 inode->i_mode &= ~current_umask();
ac27a0ec
DK
281 }
282 if (test_opt(inode->i_sb, POSIX_ACL) && acl) {
283 struct posix_acl *clone;
284 mode_t mode;
285
286 if (S_ISDIR(inode->i_mode)) {
617ba13b 287 error = ext4_set_acl(handle, inode,
ac27a0ec
DK
288 ACL_TYPE_DEFAULT, acl);
289 if (error)
290 goto cleanup;
291 }
216553c4 292 clone = posix_acl_clone(acl, GFP_NOFS);
ac27a0ec
DK
293 error = -ENOMEM;
294 if (!clone)
295 goto cleanup;
296
297 mode = inode->i_mode;
298 error = posix_acl_create_masq(clone, &mode);
299 if (error >= 0) {
300 inode->i_mode = mode;
301 if (error > 0) {
302 /* This is an extended ACL */
617ba13b 303 error = ext4_set_acl(handle, inode,
ac27a0ec
DK
304 ACL_TYPE_ACCESS, clone);
305 }
306 }
307 posix_acl_release(clone);
308 }
309cleanup:
310 posix_acl_release(acl);
311 return error;
312}
313
314/*
315 * Does chmod for an inode that may have an Access Control List. The
316 * inode->i_mode field must be updated to the desired value by the caller
317 * before calling this function.
318 * Returns 0 on success, or a negative error number.
319 *
320 * We change the ACL rather than storing some ACL entries in the file
321 * mode permission bits (which would be more efficient), because that
322 * would break once additional permissions (like ACL_APPEND, ACL_DELETE
323 * for directories) are added. There are no more bits available in the
324 * file mode.
325 *
326 * inode->i_mutex: down
327 */
328int
617ba13b 329ext4_acl_chmod(struct inode *inode)
ac27a0ec
DK
330{
331 struct posix_acl *acl, *clone;
63f57933 332 int error;
ac27a0ec
DK
333
334 if (S_ISLNK(inode->i_mode))
335 return -EOPNOTSUPP;
336 if (!test_opt(inode->i_sb, POSIX_ACL))
337 return 0;
617ba13b 338 acl = ext4_get_acl(inode, ACL_TYPE_ACCESS);
ac27a0ec
DK
339 if (IS_ERR(acl) || !acl)
340 return PTR_ERR(acl);
341 clone = posix_acl_clone(acl, GFP_KERNEL);
342 posix_acl_release(acl);
343 if (!clone)
344 return -ENOMEM;
345 error = posix_acl_chmod_masq(clone, inode->i_mode);
346 if (!error) {
347 handle_t *handle;
348 int retries = 0;
349
350 retry:
617ba13b
MC
351 handle = ext4_journal_start(inode,
352 EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
ac27a0ec
DK
353 if (IS_ERR(handle)) {
354 error = PTR_ERR(handle);
617ba13b 355 ext4_std_error(inode->i_sb, error);
ac27a0ec
DK
356 goto out;
357 }
617ba13b
MC
358 error = ext4_set_acl(handle, inode, ACL_TYPE_ACCESS, clone);
359 ext4_journal_stop(handle);
ac27a0ec 360 if (error == -ENOSPC &&
617ba13b 361 ext4_should_retry_alloc(inode->i_sb, &retries))
ac27a0ec
DK
362 goto retry;
363 }
364out:
365 posix_acl_release(clone);
366 return error;
367}
368
369/*
370 * Extended attribute handlers
371 */
372static size_t
617ba13b 373ext4_xattr_list_acl_access(struct inode *inode, char *list, size_t list_len,
ac27a0ec
DK
374 const char *name, size_t name_len)
375{
376 const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
377
378 if (!test_opt(inode->i_sb, POSIX_ACL))
379 return 0;
380 if (list && size <= list_len)
381 memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
382 return size;
383}
384
385static size_t
617ba13b 386ext4_xattr_list_acl_default(struct inode *inode, char *list, size_t list_len,
ac27a0ec
DK
387 const char *name, size_t name_len)
388{
389 const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
390
391 if (!test_opt(inode->i_sb, POSIX_ACL))
392 return 0;
393 if (list && size <= list_len)
394 memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
395 return size;
396}
397
398static int
617ba13b 399ext4_xattr_get_acl(struct inode *inode, int type, void *buffer, size_t size)
ac27a0ec
DK
400{
401 struct posix_acl *acl;
402 int error;
403
404 if (!test_opt(inode->i_sb, POSIX_ACL))
405 return -EOPNOTSUPP;
406
617ba13b 407 acl = ext4_get_acl(inode, type);
ac27a0ec
DK
408 if (IS_ERR(acl))
409 return PTR_ERR(acl);
410 if (acl == NULL)
411 return -ENODATA;
412 error = posix_acl_to_xattr(acl, buffer, size);
413 posix_acl_release(acl);
414
415 return error;
416}
417
418static int
617ba13b 419ext4_xattr_get_acl_access(struct inode *inode, const char *name,
ac27a0ec
DK
420 void *buffer, size_t size)
421{
422 if (strcmp(name, "") != 0)
423 return -EINVAL;
617ba13b 424 return ext4_xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
ac27a0ec
DK
425}
426
427static int
617ba13b 428ext4_xattr_get_acl_default(struct inode *inode, const char *name,
ac27a0ec
DK
429 void *buffer, size_t size)
430{
431 if (strcmp(name, "") != 0)
432 return -EINVAL;
617ba13b 433 return ext4_xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
ac27a0ec
DK
434}
435
436static int
617ba13b 437ext4_xattr_set_acl(struct inode *inode, int type, const void *value,
ac27a0ec
DK
438 size_t size)
439{
440 handle_t *handle;
441 struct posix_acl *acl;
442 int error, retries = 0;
443
444 if (!test_opt(inode->i_sb, POSIX_ACL))
445 return -EOPNOTSUPP;
3bd858ab 446 if (!is_owner_or_cap(inode))
ac27a0ec
DK
447 return -EPERM;
448
449 if (value) {
450 acl = posix_acl_from_xattr(value, size);
451 if (IS_ERR(acl))
452 return PTR_ERR(acl);
453 else if (acl) {
454 error = posix_acl_valid(acl);
455 if (error)
456 goto release_and_out;
457 }
458 } else
459 acl = NULL;
460
461retry:
617ba13b 462 handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
ac27a0ec
DK
463 if (IS_ERR(handle))
464 return PTR_ERR(handle);
617ba13b
MC
465 error = ext4_set_acl(handle, inode, type, acl);
466 ext4_journal_stop(handle);
467 if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
ac27a0ec
DK
468 goto retry;
469
470release_and_out:
471 posix_acl_release(acl);
472 return error;
473}
474
475static int
617ba13b 476ext4_xattr_set_acl_access(struct inode *inode, const char *name,
ac27a0ec
DK
477 const void *value, size_t size, int flags)
478{
479 if (strcmp(name, "") != 0)
480 return -EINVAL;
617ba13b 481 return ext4_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
ac27a0ec
DK
482}
483
484static int
617ba13b 485ext4_xattr_set_acl_default(struct inode *inode, const char *name,
ac27a0ec
DK
486 const void *value, size_t size, int flags)
487{
488 if (strcmp(name, "") != 0)
489 return -EINVAL;
617ba13b 490 return ext4_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
ac27a0ec
DK
491}
492
617ba13b 493struct xattr_handler ext4_xattr_acl_access_handler = {
ac27a0ec 494 .prefix = POSIX_ACL_XATTR_ACCESS,
617ba13b
MC
495 .list = ext4_xattr_list_acl_access,
496 .get = ext4_xattr_get_acl_access,
497 .set = ext4_xattr_set_acl_access,
ac27a0ec
DK
498};
499
617ba13b 500struct xattr_handler ext4_xattr_acl_default_handler = {
ac27a0ec 501 .prefix = POSIX_ACL_XATTR_DEFAULT,
617ba13b
MC
502 .list = ext4_xattr_list_acl_default,
503 .get = ext4_xattr_get_acl_default,
504 .set = ext4_xattr_set_acl_default,
ac27a0ec 505};
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