[PATCH] delete from_swap_cache BUG_ONs
[linux-ginger.git] / fs / ext2 / acl.c
blob213148c36ebef341ae8c460af7cd2d9c095a5d3b
1 /*
2 * linux/fs/ext2/acl.c
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/fs.h>
11 #include "ext2.h"
12 #include "xattr.h"
13 #include "acl.h"
16 * Convert from filesystem to in-memory representation.
18 static struct posix_acl *
19 ext2_acl_from_disk(const void *value, size_t size)
21 const char *end = (char *)value + size;
22 int n, count;
23 struct posix_acl *acl;
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;
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;
67 default:
68 goto fail;
71 if (value != end)
72 goto fail;
73 return acl;
75 fail:
76 posix_acl_release(acl);
77 return ERR_PTR(-EINVAL);
81 * Convert from in-memory to filesystem representation.
83 static void *
84 ext2_acl_to_disk(const struct posix_acl *acl, size_t *size)
86 ext2_acl_header *ext_acl;
87 char *e;
88 size_t n;
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;
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;
116 default:
117 goto fail;
120 return (char *)ext_acl;
122 fail:
123 kfree(ext_acl);
124 return ERR_PTR(-EINVAL);
127 static inline struct posix_acl *
128 ext2_iget_acl(struct inode *inode, struct posix_acl **i_acl)
130 struct posix_acl *acl = EXT2_ACL_NOT_CACHED;
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);
137 return acl;
140 static inline void
141 ext2_iset_acl(struct inode *inode, struct posix_acl **i_acl,
142 struct posix_acl *acl)
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);
152 * inode->i_sem: don't care
154 static struct posix_acl *
155 ext2_get_acl(struct inode *inode, int type)
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;
163 if (!test_opt(inode->i_sb, POSIX_ACL))
164 return NULL;
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;
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;
181 default:
182 return ERR_PTR(-EINVAL);
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);
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);
200 if (!IS_ERR(acl)) {
201 switch(type) {
202 case ACL_TYPE_ACCESS:
203 ext2_iset_acl(inode, &ei->i_acl, acl);
204 break;
206 case ACL_TYPE_DEFAULT:
207 ext2_iset_acl(inode, &ei->i_default_acl, acl);
208 break;
211 return acl;
215 * inode->i_sem: down
217 static int
218 ext2_set_acl(struct inode *inode, int type, struct posix_acl *acl)
220 struct ext2_inode_info *ei = EXT2_I(inode);
221 int name_index;
222 void *value = NULL;
223 size_t size;
224 int error;
226 if (S_ISLNK(inode->i_mode))
227 return -EOPNOTSUPP;
228 if (!test_opt(inode->i_sb, POSIX_ACL))
229 return 0;
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;
246 break;
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;
254 default:
255 return -EINVAL;
257 if (acl) {
258 value = ext2_acl_to_disk(acl, &size);
259 if (IS_ERR(value))
260 return (int)PTR_ERR(value);
263 error = ext2_xattr_set(inode, name_index, "", value, size, 0);
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;
273 case ACL_TYPE_DEFAULT:
274 ext2_iset_acl(inode, &ei->i_default_acl, acl);
275 break;
278 return error;
281 static int
282 ext2_check_acl(struct inode *inode, int mask)
284 struct posix_acl *acl = ext2_get_acl(inode, ACL_TYPE_ACCESS);
286 if (IS_ERR(acl))
287 return PTR_ERR(acl);
288 if (acl) {
289 int error = posix_acl_permission(inode, acl, mask);
290 posix_acl_release(acl);
291 return error;
294 return -EAGAIN;
298 ext2_permission(struct inode *inode, int mask, struct nameidata *nd)
300 return generic_permission(inode, mask, ext2_check_acl);
304 * Initialize the ACLs of a new inode. Called from ext2_new_inode.
306 * dir->i_sem: down
307 * inode->i_sem: up (access to inode is still exclusive)
310 ext2_init_acl(struct inode *inode, struct inode *dir)
312 struct posix_acl *acl = NULL;
313 int error = 0;
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);
321 if (!acl)
322 inode->i_mode &= ~current->fs->umask;
324 if (test_opt(inode->i_sb, POSIX_ACL) && acl) {
325 struct posix_acl *clone;
326 mode_t mode;
328 if (S_ISDIR(inode->i_mode)) {
329 error = ext2_set_acl(inode, ACL_TYPE_DEFAULT, acl);
330 if (error)
331 goto cleanup;
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);
347 posix_acl_release(clone);
349 cleanup:
350 posix_acl_release(acl);
351 return error;
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.
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.
366 * inode->i_sem: down
369 ext2_acl_chmod(struct inode *inode)
371 struct posix_acl *acl, *clone;
372 int error;
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;
393 * Extended attribut handlers
395 static size_t
396 ext2_xattr_list_acl_access(struct inode *inode, char *list, size_t list_size,
397 const char *name, size_t name_len)
399 const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
401 if (!test_opt(inode->i_sb, POSIX_ACL))
402 return 0;
403 if (list && size <= list_size)
404 memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
405 return size;
408 static size_t
409 ext2_xattr_list_acl_default(struct inode *inode, char *list, size_t list_size,
410 const char *name, size_t name_len)
412 const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
414 if (!test_opt(inode->i_sb, POSIX_ACL))
415 return 0;
416 if (list && size <= list_size)
417 memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
418 return size;
421 static int
422 ext2_xattr_get_acl(struct inode *inode, int type, void *buffer, size_t size)
424 struct posix_acl *acl;
425 int error;
427 if (!test_opt(inode->i_sb, POSIX_ACL))
428 return -EOPNOTSUPP;
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);
438 return error;
441 static int
442 ext2_xattr_get_acl_access(struct inode *inode, const char *name,
443 void *buffer, size_t size)
445 if (strcmp(name, "") != 0)
446 return -EINVAL;
447 return ext2_xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
450 static int
451 ext2_xattr_get_acl_default(struct inode *inode, const char *name,
452 void *buffer, size_t size)
454 if (strcmp(name, "") != 0)
455 return -EINVAL;
456 return ext2_xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
459 static int
460 ext2_xattr_set_acl(struct inode *inode, int type, const void *value,
461 size_t size)
463 struct posix_acl *acl;
464 int error;
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;
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;
480 } else
481 acl = NULL;
483 error = ext2_set_acl(inode, type, acl);
485 release_and_out:
486 posix_acl_release(acl);
487 return error;
490 static int
491 ext2_xattr_set_acl_access(struct inode *inode, const char *name,
492 const void *value, size_t size, int flags)
494 if (strcmp(name, "") != 0)
495 return -EINVAL;
496 return ext2_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
499 static int
500 ext2_xattr_set_acl_default(struct inode *inode, const char *name,
501 const void *value, size_t size, int flags)
503 if (strcmp(name, "") != 0)
504 return -EINVAL;
505 return ext2_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
508 struct xattr_handler ext2_xattr_acl_access_handler = {
509 .prefix = POSIX_ACL_XATTR_ACCESS,
510 .list = ext2_xattr_list_acl_access,
511 .get = ext2_xattr_get_acl_access,
512 .set = ext2_xattr_set_acl_access,
515 struct xattr_handler ext2_xattr_acl_default_handler = {
516 .prefix = POSIX_ACL_XATTR_DEFAULT,
517 .list = ext2_xattr_list_acl_default,
518 .get = ext2_xattr_get_acl_default,
519 .set = ext2_xattr_set_acl_default,