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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 "ext4_jbd2.h"
13#include "ext4.h"
14#include "xattr.h"
15#include "acl.h"
16
17
18
19
20static struct posix_acl *
21ext4_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;
26
27 if (!value)
28 return NULL;
29 if (size < sizeof(ext4_acl_header))
30 return ERR_PTR(-EINVAL);
31 if (((ext4_acl_header *)value)->a_version !=
32 cpu_to_le32(EXT4_ACL_VERSION))
33 return ERR_PTR(-EINVAL);
34 value = (char *)value + sizeof(ext4_acl_header);
35 count = ext4_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_NOFS);
41 if (!acl)
42 return ERR_PTR(-ENOMEM);
43 for (n = 0; n < count; n++) {
44 ext4_acl_entry *entry =
45 (ext4_acl_entry *)value;
46 if ((char *)value + sizeof(ext4_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
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)
65 goto fail;
66 acl->a_entries[n].e_id =
67 le32_to_cpu(entry->e_id);
68 break;
69
70 default:
71 goto fail;
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
85
86static void *
87ext4_acl_to_disk(const struct posix_acl *acl, size_t *size)
88{
89 ext4_acl_header *ext_acl;
90 char *e;
91 size_t n;
92
93 *size = ext4_acl_size(acl->a_count);
94 ext_acl = kmalloc(sizeof(ext4_acl_header) + acl->a_count *
95 sizeof(ext4_acl_entry), GFP_NOFS);
96 if (!ext_acl)
97 return ERR_PTR(-ENOMEM);
98 ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION);
99 e = (char *)ext_acl + sizeof(ext4_acl_header);
100 for (n = 0; n < acl->a_count; n++) {
101 ext4_acl_entry *entry = (ext4_acl_entry *)e;
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);
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;
120 }
121 }
122 return (char *)ext_acl;
123
124fail:
125 kfree(ext_acl);
126 return ERR_PTR(-EINVAL);
127}
128
129
130
131
132
133
134static struct posix_acl *
135ext4_get_acl(struct inode *inode, int type)
136{
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
145 acl = get_cached_acl(inode, type);
146 if (acl != ACL_NOT_CACHED)
147 return acl;
148
149 switch (type) {
150 case ACL_TYPE_ACCESS:
151 name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
152 break;
153 case ACL_TYPE_DEFAULT:
154 name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
155 break;
156 default:
157 BUG();
158 }
159 retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
160 if (retval > 0) {
161 value = kmalloc(retval, GFP_NOFS);
162 if (!value)
163 return ERR_PTR(-ENOMEM);
164 retval = ext4_xattr_get(inode, name_index, "", value, retval);
165 }
166 if (retval > 0)
167 acl = ext4_acl_from_disk(value, retval);
168 else if (retval == -ENODATA || retval == -ENOSYS)
169 acl = NULL;
170 else
171 acl = ERR_PTR(retval);
172 kfree(value);
173
174 if (!IS_ERR(acl))
175 set_cached_acl(inode, type, acl);
176
177 return acl;
178}
179
180
181
182
183
184
185static int
186ext4_set_acl(handle_t *handle, struct inode *inode, int type,
187 struct posix_acl *acl)
188{
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
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;
210 }
211 }
212 break;
213
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;
219
220 default:
221 return -EINVAL;
222 }
223 if (acl) {
224 value = ext4_acl_to_disk(acl, &size);
225 if (IS_ERR(value))
226 return (int)PTR_ERR(value);
227 }
228
229 error = ext4_xattr_set_handle(handle, inode, name_index, "",
230 value, size, 0);
231
232 kfree(value);
233 if (!error)
234 set_cached_acl(inode, type, acl);
235
236 return error;
237}
238
239int
240ext4_check_acl(struct inode *inode, int mask)
241{
242 struct posix_acl *acl = ext4_get_acl(inode, ACL_TYPE_ACCESS);
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
255
256
257
258
259
260
261int
262ext4_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)
263{
264 struct posix_acl *acl = NULL;
265 int error = 0;
266
267 if (!S_ISLNK(inode->i_mode)) {
268 if (test_opt(dir->i_sb, POSIX_ACL)) {
269 acl = ext4_get_acl(dir, ACL_TYPE_DEFAULT);
270 if (IS_ERR(acl))
271 return PTR_ERR(acl);
272 }
273 if (!acl)
274 inode->i_mode &= ~current_umask();
275 }
276 if (test_opt(inode->i_sb, POSIX_ACL) && acl) {
277 struct posix_acl *clone;
278 mode_t mode;
279
280 if (S_ISDIR(inode->i_mode)) {
281 error = ext4_set_acl(handle, inode,
282 ACL_TYPE_DEFAULT, acl);
283 if (error)
284 goto cleanup;
285 }
286 clone = posix_acl_clone(acl, GFP_NOFS);
287 error = -ENOMEM;
288 if (!clone)
289 goto cleanup;
290
291 mode = inode->i_mode;
292 error = posix_acl_create_masq(clone, &mode);
293 if (error >= 0) {
294 inode->i_mode = mode;
295 if (error > 0) {
296
297 error = ext4_set_acl(handle, inode,
298 ACL_TYPE_ACCESS, clone);
299 }
300 }
301 posix_acl_release(clone);
302 }
303cleanup:
304 posix_acl_release(acl);
305 return error;
306}
307
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320
321
322int
323ext4_acl_chmod(struct inode *inode)
324{
325 struct posix_acl *acl, *clone;
326 int error;
327
328 if (S_ISLNK(inode->i_mode))
329 return -EOPNOTSUPP;
330 if (!test_opt(inode->i_sb, POSIX_ACL))
331 return 0;
332 acl = ext4_get_acl(inode, ACL_TYPE_ACCESS);
333 if (IS_ERR(acl) || !acl)
334 return PTR_ERR(acl);
335 clone = posix_acl_clone(acl, GFP_KERNEL);
336 posix_acl_release(acl);
337 if (!clone)
338 return -ENOMEM;
339 error = posix_acl_chmod_masq(clone, inode->i_mode);
340 if (!error) {
341 handle_t *handle;
342 int retries = 0;
343
344 retry:
345 handle = ext4_journal_start(inode,
346 EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
347 if (IS_ERR(handle)) {
348 error = PTR_ERR(handle);
349 ext4_std_error(inode->i_sb, error);
350 goto out;
351 }
352 error = ext4_set_acl(handle, inode, ACL_TYPE_ACCESS, clone);
353 ext4_journal_stop(handle);
354 if (error == -ENOSPC &&
355 ext4_should_retry_alloc(inode->i_sb, &retries))
356 goto retry;
357 }
358out:
359 posix_acl_release(clone);
360 return error;
361}
362
363
364
365
366static size_t
367ext4_xattr_list_acl_access(struct inode *inode, char *list, size_t list_len,
368 const char *name, size_t name_len)
369{
370 const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
371
372 if (!test_opt(inode->i_sb, POSIX_ACL))
373 return 0;
374 if (list && size <= list_len)
375 memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
376 return size;
377}
378
379static size_t
380ext4_xattr_list_acl_default(struct inode *inode, char *list, size_t list_len,
381 const char *name, size_t name_len)
382{
383 const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
384
385 if (!test_opt(inode->i_sb, POSIX_ACL))
386 return 0;
387 if (list && size <= list_len)
388 memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
389 return size;
390}
391
392static int
393ext4_xattr_get_acl(struct inode *inode, int type, void *buffer, size_t size)
394{
395 struct posix_acl *acl;
396 int error;
397
398 if (!test_opt(inode->i_sb, POSIX_ACL))
399 return -EOPNOTSUPP;
400
401 acl = ext4_get_acl(inode, type);
402 if (IS_ERR(acl))
403 return PTR_ERR(acl);
404 if (acl == NULL)
405 return -ENODATA;
406 error = posix_acl_to_xattr(acl, buffer, size);
407 posix_acl_release(acl);
408
409 return error;
410}
411
412static int
413ext4_xattr_get_acl_access(struct inode *inode, const char *name,
414 void *buffer, size_t size)
415{
416 if (strcmp(name, "") != 0)
417 return -EINVAL;
418 return ext4_xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
419}
420
421static int
422ext4_xattr_get_acl_default(struct inode *inode, const char *name,
423 void *buffer, size_t size)
424{
425 if (strcmp(name, "") != 0)
426 return -EINVAL;
427 return ext4_xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
428}
429
430static int
431ext4_xattr_set_acl(struct inode *inode, int type, const void *value,
432 size_t size)
433{
434 handle_t *handle;
435 struct posix_acl *acl;
436 int error, retries = 0;
437
438 if (!test_opt(inode->i_sb, POSIX_ACL))
439 return -EOPNOTSUPP;
440 if (!is_owner_or_cap(inode))
441 return -EPERM;
442
443 if (value) {
444 acl = posix_acl_from_xattr(value, size);
445 if (IS_ERR(acl))
446 return PTR_ERR(acl);
447 else if (acl) {
448 error = posix_acl_valid(acl);
449 if (error)
450 goto release_and_out;
451 }
452 } else
453 acl = NULL;
454
455retry:
456 handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
457 if (IS_ERR(handle))
458 return PTR_ERR(handle);
459 error = ext4_set_acl(handle, inode, type, acl);
460 ext4_journal_stop(handle);
461 if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
462 goto retry;
463
464release_and_out:
465 posix_acl_release(acl);
466 return error;
467}
468
469static int
470ext4_xattr_set_acl_access(struct inode *inode, const char *name,
471 const void *value, size_t size, int flags)
472{
473 if (strcmp(name, "") != 0)
474 return -EINVAL;
475 return ext4_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
476}
477
478static int
479ext4_xattr_set_acl_default(struct inode *inode, const char *name,
480 const void *value, size_t size, int flags)
481{
482 if (strcmp(name, "") != 0)
483 return -EINVAL;
484 return ext4_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
485}
486
487struct xattr_handler ext4_xattr_acl_access_handler = {
488 .prefix = POSIX_ACL_XATTR_ACCESS,
489 .list = ext4_xattr_list_acl_access,
490 .get = ext4_xattr_get_acl_access,
491 .set = ext4_xattr_set_acl_access,
492};
493
494struct xattr_handler ext4_xattr_acl_default_handler = {
495 .prefix = POSIX_ACL_XATTR_DEFAULT,
496 .list = ext4_xattr_list_acl_default,
497 .get = ext4_xattr_get_acl_default,
498 .set = ext4_xattr_set_acl_default,
499};
500
