4 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
7 #include <linux/capability.h>
8 #include <linux/init.h>
9 #include <linux/sched.h>
10 #include <linux/slab.h>
17 * Convert from filesystem to in-memory representation.
19 static struct posix_acl *
20 ext2_acl_from_disk(const void *value, size_t size)
22 const char *end = (char *)value + size;
24 struct posix_acl *acl;
28 if (size < sizeof(ext2_acl_header))
29 return ERR_PTR(-EINVAL);
30 if (((ext2_acl_header *)value)->a_version !=
31 cpu_to_le32(EXT2_ACL_VERSION))
32 return ERR_PTR(-EINVAL);
33 value = (char *)value + sizeof(ext2_acl_header);
34 count = ext2_acl_count(size);
36 return ERR_PTR(-EINVAL);
39 acl = posix_acl_alloc(count, GFP_KERNEL);
41 return ERR_PTR(-ENOMEM);
42 for (n=0; n < count; n++) {
43 ext2_acl_entry *entry =
44 (ext2_acl_entry *)value;
45 if ((char *)value + sizeof(ext2_acl_entry_short) > end)
47 acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
48 acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
49 switch(acl->a_entries[n].e_tag) {
54 value = (char *)value +
55 sizeof(ext2_acl_entry_short);
56 acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
61 value = (char *)value + sizeof(ext2_acl_entry);
62 if ((char *)value > end)
64 acl->a_entries[n].e_id =
65 le32_to_cpu(entry->e_id);
77 posix_acl_release(acl);
78 return ERR_PTR(-EINVAL);
82 * Convert from in-memory to filesystem representation.
85 ext2_acl_to_disk(const struct posix_acl *acl, size_t *size)
87 ext2_acl_header *ext_acl;
91 *size = ext2_acl_size(acl->a_count);
92 ext_acl = kmalloc(sizeof(ext2_acl_header) + acl->a_count *
93 sizeof(ext2_acl_entry), GFP_KERNEL);
95 return ERR_PTR(-ENOMEM);
96 ext_acl->a_version = cpu_to_le32(EXT2_ACL_VERSION);
97 e = (char *)ext_acl + sizeof(ext2_acl_header);
98 for (n=0; n < acl->a_count; n++) {
99 ext2_acl_entry *entry = (ext2_acl_entry *)e;
100 entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
101 entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
102 switch(acl->a_entries[n].e_tag) {
106 cpu_to_le32(acl->a_entries[n].e_id);
107 e += sizeof(ext2_acl_entry);
114 e += sizeof(ext2_acl_entry_short);
121 return (char *)ext_acl;
125 return ERR_PTR(-EINVAL);
129 * inode->i_mutex: don't care
132 ext2_get_acl(struct inode *inode, int type)
136 struct posix_acl *acl;
139 if (!test_opt(inode->i_sb, POSIX_ACL))
142 acl = get_cached_acl(inode, type);
143 if (acl != ACL_NOT_CACHED)
147 case ACL_TYPE_ACCESS:
148 name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;
150 case ACL_TYPE_DEFAULT:
151 name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT;
156 retval = ext2_xattr_get(inode, name_index, "", NULL, 0);
158 value = kmalloc(retval, GFP_KERNEL);
160 return ERR_PTR(-ENOMEM);
161 retval = ext2_xattr_get(inode, name_index, "", value, retval);
164 acl = ext2_acl_from_disk(value, retval);
165 else if (retval == -ENODATA || retval == -ENOSYS)
168 acl = ERR_PTR(retval);
172 set_cached_acl(inode, type, acl);
178 __ext2_set_acl(struct inode *inode, struct posix_acl *acl, int type)
185 if (S_ISLNK(inode->i_mode))
187 if (!test_opt(inode->i_sb, POSIX_ACL))
191 case ACL_TYPE_ACCESS:
192 name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;
195 case ACL_TYPE_DEFAULT:
196 name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT;
197 if (!S_ISDIR(inode->i_mode))
198 return acl ? -EACCES : 0;
205 value = ext2_acl_to_disk(acl, &size);
207 return (int)PTR_ERR(value);
210 error = ext2_xattr_set(inode, name_index, "", value, size, 0);
214 set_cached_acl(inode, type, acl);
219 * inode->i_mutex: down
222 ext2_set_acl(struct inode *inode, struct posix_acl *acl, int type)
226 umode_t mode = inode->i_mode;
228 if (type == ACL_TYPE_ACCESS && acl) {
229 error = posix_acl_update_mode(inode, &mode, &acl);
234 error = __ext2_set_acl(inode, acl, type);
235 if (!error && update_mode) {
236 inode->i_mode = mode;
237 inode->i_ctime = CURRENT_TIME_SEC;
238 mark_inode_dirty(inode);
244 * Initialize the ACLs of a new inode. Called from ext2_new_inode.
247 * inode->i_mutex: up (access to inode is still exclusive)
250 ext2_init_acl(struct inode *inode, struct inode *dir)
252 struct posix_acl *acl = NULL;
255 if (!S_ISLNK(inode->i_mode)) {
256 if (test_opt(dir->i_sb, POSIX_ACL)) {
257 acl = ext2_get_acl(dir, ACL_TYPE_DEFAULT);
262 inode->i_mode &= ~current_umask();
264 if (test_opt(inode->i_sb, POSIX_ACL) && acl) {
265 if (S_ISDIR(inode->i_mode)) {
266 error = __ext2_set_acl(inode, acl, ACL_TYPE_DEFAULT);
270 error = posix_acl_create(&acl, GFP_KERNEL, &inode->i_mode);
274 /* This is an extended ACL */
275 error = __ext2_set_acl(inode, acl, ACL_TYPE_ACCESS);
279 posix_acl_release(acl);
284 * Does chmod for an inode that may have an Access Control List. The
285 * inode->i_mode field must be updated to the desired value by the caller
286 * before calling this function.
287 * Returns 0 on success, or a negative error number.
289 * We change the ACL rather than storing some ACL entries in the file
290 * mode permission bits (which would be more efficient), because that
291 * would break once additional permissions (like ACL_APPEND, ACL_DELETE
292 * for directories) are added. There are no more bits available in the
295 * inode->i_mutex: down
298 ext2_acl_chmod(struct inode *inode)
300 struct posix_acl *acl;
303 if (!test_opt(inode->i_sb, POSIX_ACL))
305 if (S_ISLNK(inode->i_mode))
307 acl = ext2_get_acl(inode, ACL_TYPE_ACCESS);
308 if (IS_ERR(acl) || !acl)
310 error = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
313 error = ext2_set_acl(inode, acl, ACL_TYPE_ACCESS);
314 posix_acl_release(acl);
319 * Extended attribut handlers
322 ext2_xattr_list_acl_access(struct dentry *dentry, char *list, size_t list_size,
323 const char *name, size_t name_len, int type)
325 const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
327 if (!test_opt(dentry->d_sb, POSIX_ACL))
329 if (list && size <= list_size)
330 memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
335 ext2_xattr_list_acl_default(struct dentry *dentry, char *list, size_t list_size,
336 const char *name, size_t name_len, int type)
338 const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
340 if (!test_opt(dentry->d_sb, POSIX_ACL))
342 if (list && size <= list_size)
343 memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
348 ext2_xattr_get_acl(struct dentry *dentry, const char *name, void *buffer,
349 size_t size, int type)
351 struct posix_acl *acl;
354 if (strcmp(name, "") != 0)
356 if (!test_opt(dentry->d_sb, POSIX_ACL))
359 acl = ext2_get_acl(dentry->d_inode, type);
364 error = posix_acl_to_xattr(acl, buffer, size);
365 posix_acl_release(acl);
371 ext2_xattr_set_acl(struct dentry *dentry, const char *name, const void *value,
372 size_t size, int flags, int type)
374 struct posix_acl *acl;
377 if (strcmp(name, "") != 0)
379 if (!test_opt(dentry->d_sb, POSIX_ACL))
381 if (!inode_owner_or_capable(dentry->d_inode))
385 acl = posix_acl_from_xattr(value, size);
389 error = posix_acl_valid(acl);
391 goto release_and_out;
396 error = ext2_set_acl(dentry->d_inode, acl, type);
399 posix_acl_release(acl);
403 const struct xattr_handler ext2_xattr_acl_access_handler = {
404 .prefix = POSIX_ACL_XATTR_ACCESS,
405 .flags = ACL_TYPE_ACCESS,
406 .list = ext2_xattr_list_acl_access,
407 .get = ext2_xattr_get_acl,
408 .set = ext2_xattr_set_acl,
411 const struct xattr_handler ext2_xattr_acl_default_handler = {
412 .prefix = POSIX_ACL_XATTR_DEFAULT,
413 .flags = ACL_TYPE_DEFAULT,
414 .list = ext2_xattr_list_acl_default,
415 .get = ext2_xattr_get_acl,
416 .set = ext2_xattr_set_acl,