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-rw-r--r--fs/ext2/acl.c518
1 files changed, 518 insertions, 0 deletions
diff --git a/fs/ext2/acl.c b/fs/ext2/acl.c
new file mode 100644
index 000000000000..8369ee8d28c4
--- /dev/null
+++ b/fs/ext2/acl.c
@@ -0,0 +1,518 @@
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 */
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
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
295int
296ext2_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 */
307int
308ext2_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 }
347cleanup:
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 */
366int
367ext2_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 */
393static size_t
394ext2_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
406static size_t
407ext2_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
419static int
420ext2_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
439static int
440ext2_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
448static int
449ext2_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
457static int
458ext2_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
483release_and_out:
484 posix_acl_release(acl);
485 return error;
486}
487
488static int
489ext2_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
497static int
498ext2_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
506struct 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
513struct 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};
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-28 07:15:39 -0500