switch posix_acl_create() to umode_t *
[linux-3.10.git] / fs / ext3 / acl.c
1 /*
2  * linux/fs/ext3/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/capability.h>
11 #include <linux/fs.h>
12 #include <linux/ext3_jbd.h>
13 #include <linux/ext3_fs.h>
14 #include "xattr.h"
15 #include "acl.h"
16
17 /*
18  * Convert from filesystem to in-memory representation.
19  */
20 static struct posix_acl *
21 ext3_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(ext3_acl_header))
30                  return ERR_PTR(-EINVAL);
31         if (((ext3_acl_header *)value)->a_version !=
32             cpu_to_le32(EXT3_ACL_VERSION))
33                 return ERR_PTR(-EINVAL);
34         value = (char *)value + sizeof(ext3_acl_header);
35         count = ext3_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                 ext3_acl_entry *entry =
45                         (ext3_acl_entry *)value;
46                 if ((char *)value + sizeof(ext3_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                 switch(acl->a_entries[n].e_tag) {
51                         case ACL_USER_OBJ:
52                         case ACL_GROUP_OBJ:
53                         case ACL_MASK:
54                         case ACL_OTHER:
55                                 value = (char *)value +
56                                         sizeof(ext3_acl_entry_short);
57                                 acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
58                                 break;
59
60                         case ACL_USER:
61                         case ACL_GROUP:
62                                 value = (char *)value + sizeof(ext3_acl_entry);
63                                 if ((char *)value > end)
64                                         goto fail;
65                                 acl->a_entries[n].e_id =
66                                         le32_to_cpu(entry->e_id);
67                                 break;
68
69                         default:
70                                 goto fail;
71                 }
72         }
73         if (value != end)
74                 goto fail;
75         return acl;
76
77 fail:
78         posix_acl_release(acl);
79         return ERR_PTR(-EINVAL);
80 }
81
82 /*
83  * Convert from in-memory to filesystem representation.
84  */
85 static void *
86 ext3_acl_to_disk(const struct posix_acl *acl, size_t *size)
87 {
88         ext3_acl_header *ext_acl;
89         char *e;
90         size_t n;
91
92         *size = ext3_acl_size(acl->a_count);
93         ext_acl = kmalloc(sizeof(ext3_acl_header) + acl->a_count *
94                         sizeof(ext3_acl_entry), GFP_NOFS);
95         if (!ext_acl)
96                 return ERR_PTR(-ENOMEM);
97         ext_acl->a_version = cpu_to_le32(EXT3_ACL_VERSION);
98         e = (char *)ext_acl + sizeof(ext3_acl_header);
99         for (n=0; n < acl->a_count; n++) {
100                 ext3_acl_entry *entry = (ext3_acl_entry *)e;
101                 entry->e_tag  = cpu_to_le16(acl->a_entries[n].e_tag);
102                 entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
103                 switch(acl->a_entries[n].e_tag) {
104                         case ACL_USER:
105                         case ACL_GROUP:
106                                 entry->e_id =
107                                         cpu_to_le32(acl->a_entries[n].e_id);
108                                 e += sizeof(ext3_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(ext3_acl_entry_short);
116                                 break;
117
118                         default:
119                                 goto fail;
120                 }
121         }
122         return (char *)ext_acl;
123
124 fail:
125         kfree(ext_acl);
126         return ERR_PTR(-EINVAL);
127 }
128
129 /*
130  * Inode operation get_posix_acl().
131  *
132  * inode->i_mutex: don't care
133  */
134 struct posix_acl *
135 ext3_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 = EXT3_XATTR_INDEX_POSIX_ACL_ACCESS;
152                 break;
153         case ACL_TYPE_DEFAULT:
154                 name_index = EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT;
155                 break;
156         default:
157                 BUG();
158         }
159
160         retval = ext3_xattr_get(inode, name_index, "", NULL, 0);
161         if (retval > 0) {
162                 value = kmalloc(retval, GFP_NOFS);
163                 if (!value)
164                         return ERR_PTR(-ENOMEM);
165                 retval = ext3_xattr_get(inode, name_index, "", value, retval);
166         }
167         if (retval > 0)
168                 acl = ext3_acl_from_disk(value, retval);
169         else if (retval == -ENODATA || retval == -ENOSYS)
170                 acl = NULL;
171         else
172                 acl = ERR_PTR(retval);
173         kfree(value);
174
175         if (!IS_ERR(acl))
176                 set_cached_acl(inode, type, acl);
177
178         return acl;
179 }
180
181 /*
182  * Set the access or default ACL of an inode.
183  *
184  * inode->i_mutex: down unless called from ext3_new_inode
185  */
186 static int
187 ext3_set_acl(handle_t *handle, struct inode *inode, int type,
188              struct posix_acl *acl)
189 {
190         int name_index;
191         void *value = NULL;
192         size_t size = 0;
193         int error;
194
195         if (S_ISLNK(inode->i_mode))
196                 return -EOPNOTSUPP;
197
198         switch(type) {
199                 case ACL_TYPE_ACCESS:
200                         name_index = EXT3_XATTR_INDEX_POSIX_ACL_ACCESS;
201                         if (acl) {
202                                 mode_t mode = inode->i_mode;
203                                 error = posix_acl_equiv_mode(acl, &mode);
204                                 if (error < 0)
205                                         return error;
206                                 else {
207                                         inode->i_mode = mode;
208                                         inode->i_ctime = CURRENT_TIME_SEC;
209                                         ext3_mark_inode_dirty(handle, inode);
210                                         if (error == 0)
211                                                 acl = NULL;
212                                 }
213                         }
214                         break;
215
216                 case ACL_TYPE_DEFAULT:
217                         name_index = EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT;
218                         if (!S_ISDIR(inode->i_mode))
219                                 return acl ? -EACCES : 0;
220                         break;
221
222                 default:
223                         return -EINVAL;
224         }
225         if (acl) {
226                 value = ext3_acl_to_disk(acl, &size);
227                 if (IS_ERR(value))
228                         return (int)PTR_ERR(value);
229         }
230
231         error = ext3_xattr_set_handle(handle, inode, name_index, "",
232                                       value, size, 0);
233
234         kfree(value);
235
236         if (!error)
237                 set_cached_acl(inode, type, acl);
238
239         return error;
240 }
241
242 /*
243  * Initialize the ACLs of a new inode. Called from ext3_new_inode.
244  *
245  * dir->i_mutex: down
246  * inode->i_mutex: up (access to inode is still exclusive)
247  */
248 int
249 ext3_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)
250 {
251         struct posix_acl *acl = NULL;
252         int error = 0;
253
254         if (!S_ISLNK(inode->i_mode)) {
255                 if (test_opt(dir->i_sb, POSIX_ACL)) {
256                         acl = ext3_get_acl(dir, ACL_TYPE_DEFAULT);
257                         if (IS_ERR(acl))
258                                 return PTR_ERR(acl);
259                 }
260                 if (!acl)
261                         inode->i_mode &= ~current_umask();
262         }
263         if (test_opt(inode->i_sb, POSIX_ACL) && acl) {
264                 if (S_ISDIR(inode->i_mode)) {
265                         error = ext3_set_acl(handle, inode,
266                                              ACL_TYPE_DEFAULT, acl);
267                         if (error)
268                                 goto cleanup;
269                 }
270                 error = posix_acl_create(&acl, GFP_NOFS, &inode->i_mode);
271                 if (error < 0)
272                         return error;
273
274                 if (error > 0) {
275                         /* This is an extended ACL */
276                         error = ext3_set_acl(handle, inode, ACL_TYPE_ACCESS, acl);
277                 }
278         }
279 cleanup:
280         posix_acl_release(acl);
281         return error;
282 }
283
284 /*
285  * Does chmod for an inode that may have an Access Control List. The
286  * inode->i_mode field must be updated to the desired value by the caller
287  * before calling this function.
288  * Returns 0 on success, or a negative error number.
289  *
290  * We change the ACL rather than storing some ACL entries in the file
291  * mode permission bits (which would be more efficient), because that
292  * would break once additional permissions (like  ACL_APPEND, ACL_DELETE
293  * for directories) are added. There are no more bits available in the
294  * file mode.
295  *
296  * inode->i_mutex: down
297  */
298 int
299 ext3_acl_chmod(struct inode *inode)
300 {
301         struct posix_acl *acl;
302         handle_t *handle;
303         int retries = 0;
304         int error;
305
306         if (S_ISLNK(inode->i_mode))
307                 return -EOPNOTSUPP;
308         if (!test_opt(inode->i_sb, POSIX_ACL))
309                 return 0;
310         acl = ext3_get_acl(inode, ACL_TYPE_ACCESS);
311         if (IS_ERR(acl) || !acl)
312                 return PTR_ERR(acl);
313         error = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
314         if (error)
315                 return error;
316 retry:
317         handle = ext3_journal_start(inode,
318                         EXT3_DATA_TRANS_BLOCKS(inode->i_sb));
319         if (IS_ERR(handle)) {
320                 error = PTR_ERR(handle);
321                 ext3_std_error(inode->i_sb, error);
322                 goto out;
323         }
324         error = ext3_set_acl(handle, inode, ACL_TYPE_ACCESS, acl);
325         ext3_journal_stop(handle);
326         if (error == -ENOSPC &&
327             ext3_should_retry_alloc(inode->i_sb, &retries))
328                 goto retry;
329 out:
330         posix_acl_release(acl);
331         return error;
332 }
333
334 /*
335  * Extended attribute handlers
336  */
337 static size_t
338 ext3_xattr_list_acl_access(struct dentry *dentry, char *list, size_t list_len,
339                            const char *name, size_t name_len, int type)
340 {
341         const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
342
343         if (!test_opt(dentry->d_sb, POSIX_ACL))
344                 return 0;
345         if (list && size <= list_len)
346                 memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
347         return size;
348 }
349
350 static size_t
351 ext3_xattr_list_acl_default(struct dentry *dentry, char *list, size_t list_len,
352                             const char *name, size_t name_len, int type)
353 {
354         const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
355
356         if (!test_opt(dentry->d_sb, POSIX_ACL))
357                 return 0;
358         if (list && size <= list_len)
359                 memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
360         return size;
361 }
362
363 static int
364 ext3_xattr_get_acl(struct dentry *dentry, const char *name, void *buffer,
365                    size_t size, int type)
366 {
367         struct posix_acl *acl;
368         int error;
369
370         if (strcmp(name, "") != 0)
371                 return -EINVAL;
372         if (!test_opt(dentry->d_sb, POSIX_ACL))
373                 return -EOPNOTSUPP;
374
375         acl = ext3_get_acl(dentry->d_inode, type);
376         if (IS_ERR(acl))
377                 return PTR_ERR(acl);
378         if (acl == NULL)
379                 return -ENODATA;
380         error = posix_acl_to_xattr(acl, buffer, size);
381         posix_acl_release(acl);
382
383         return error;
384 }
385
386 static int
387 ext3_xattr_set_acl(struct dentry *dentry, const char *name, const void *value,
388                    size_t size, int flags, int type)
389 {
390         struct inode *inode = dentry->d_inode;
391         handle_t *handle;
392         struct posix_acl *acl;
393         int error, retries = 0;
394
395         if (strcmp(name, "") != 0)
396                 return -EINVAL;
397         if (!test_opt(inode->i_sb, POSIX_ACL))
398                 return -EOPNOTSUPP;
399         if (!inode_owner_or_capable(inode))
400                 return -EPERM;
401
402         if (value) {
403                 acl = posix_acl_from_xattr(value, size);
404                 if (IS_ERR(acl))
405                         return PTR_ERR(acl);
406                 else if (acl) {
407                         error = posix_acl_valid(acl);
408                         if (error)
409                                 goto release_and_out;
410                 }
411         } else
412                 acl = NULL;
413
414 retry:
415         handle = ext3_journal_start(inode, EXT3_DATA_TRANS_BLOCKS(inode->i_sb));
416         if (IS_ERR(handle))
417                 return PTR_ERR(handle);
418         error = ext3_set_acl(handle, inode, type, acl);
419         ext3_journal_stop(handle);
420         if (error == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
421                 goto retry;
422
423 release_and_out:
424         posix_acl_release(acl);
425         return error;
426 }
427
428 const struct xattr_handler ext3_xattr_acl_access_handler = {
429         .prefix = POSIX_ACL_XATTR_ACCESS,
430         .flags  = ACL_TYPE_ACCESS,
431         .list   = ext3_xattr_list_acl_access,
432         .get    = ext3_xattr_get_acl,
433         .set    = ext3_xattr_set_acl,
434 };
435
436 const struct xattr_handler ext3_xattr_acl_default_handler = {
437         .prefix = POSIX_ACL_XATTR_DEFAULT,
438         .flags  = ACL_TYPE_DEFAULT,
439         .list   = ext3_xattr_list_acl_default,
440         .get    = ext3_xattr_get_acl,
441         .set    = ext3_xattr_set_acl,
442 };