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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/fs/ext2/acl.c
3 *
4 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
5 */
6
Randy Dunlap16f7e0f2006-01-11 12:17:46 -08007#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07008#include <linux/init.h>
9#include <linux/sched.h>
10#include <linux/slab.h>
11#include <linux/fs.h>
12#include "ext2.h"
13#include "xattr.h"
14#include "acl.h"
15
16/*
17 * Convert from filesystem to in-memory representation.
18 */
19static struct posix_acl *
20ext2_acl_from_disk(const void *value, size_t size)
21{
22 const char *end = (char *)value + size;
23 int n, count;
24 struct posix_acl *acl;
25
26 if (!value)
27 return NULL;
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);
35 if (count < 0)
36 return ERR_PTR(-EINVAL);
37 if (count == 0)
38 return NULL;
39 acl = posix_acl_alloc(count, GFP_KERNEL);
40 if (!acl)
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)
46 goto fail;
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) {
50 case ACL_USER_OBJ:
51 case ACL_GROUP_OBJ:
52 case ACL_MASK:
53 case ACL_OTHER:
54 value = (char *)value +
55 sizeof(ext2_acl_entry_short);
56 acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
57 break;
58
59 case ACL_USER:
60 case ACL_GROUP:
61 value = (char *)value + sizeof(ext2_acl_entry);
62 if ((char *)value > end)
63 goto fail;
64 acl->a_entries[n].e_id =
65 le32_to_cpu(entry->e_id);
66 break;
67
68 default:
69 goto fail;
70 }
71 }
72 if (value != end)
73 goto fail;
74 return acl;
75
76fail:
77 posix_acl_release(acl);
78 return ERR_PTR(-EINVAL);
79}
80
81/*
82 * Convert from in-memory to filesystem representation.
83 */
84static void *
85ext2_acl_to_disk(const struct posix_acl *acl, size_t *size)
86{
87 ext2_acl_header *ext_acl;
88 char *e;
89 size_t n;
90
91 *size = ext2_acl_size(acl->a_count);
Panagiotis Issarisf52720c2006-09-27 01:49:39 -070092 ext_acl = kmalloc(sizeof(ext2_acl_header) + acl->a_count *
93 sizeof(ext2_acl_entry), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -070094 if (!ext_acl)
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) {
103 case ACL_USER:
104 case ACL_GROUP:
105 entry->e_id =
106 cpu_to_le32(acl->a_entries[n].e_id);
107 e += sizeof(ext2_acl_entry);
108 break;
109
110 case ACL_USER_OBJ:
111 case ACL_GROUP_OBJ:
112 case ACL_MASK:
113 case ACL_OTHER:
114 e += sizeof(ext2_acl_entry_short);
115 break;
116
117 default:
118 goto fail;
119 }
120 }
121 return (char *)ext_acl;
122
123fail:
124 kfree(ext_acl);
125 return ERR_PTR(-EINVAL);
126}
127
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128/*
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800129 * inode->i_mutex: don't care
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 */
131static struct posix_acl *
132ext2_get_acl(struct inode *inode, int type)
133{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134 int name_index;
135 char *value = NULL;
136 struct posix_acl *acl;
137 int retval;
138
139 if (!test_opt(inode->i_sb, POSIX_ACL))
140 return NULL;
141
Al Viro073aaa12009-06-09 12:11:54 -0400142 acl = get_cached_acl(inode, type);
143 if (acl != ACL_NOT_CACHED)
144 return acl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145
Al Viro073aaa12009-06-09 12:11:54 -0400146 switch (type) {
147 case ACL_TYPE_ACCESS:
148 name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;
149 break;
150 case ACL_TYPE_DEFAULT:
151 name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT;
152 break;
153 default:
154 BUG();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 }
156 retval = ext2_xattr_get(inode, name_index, "", NULL, 0);
157 if (retval > 0) {
158 value = kmalloc(retval, GFP_KERNEL);
159 if (!value)
160 return ERR_PTR(-ENOMEM);
161 retval = ext2_xattr_get(inode, name_index, "", value, retval);
162 }
163 if (retval > 0)
164 acl = ext2_acl_from_disk(value, retval);
165 else if (retval == -ENODATA || retval == -ENOSYS)
166 acl = NULL;
167 else
168 acl = ERR_PTR(retval);
Jesper Juhlf99d49a2005-11-07 01:01:34 -0800169 kfree(value);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170
Al Viro073aaa12009-06-09 12:11:54 -0400171 if (!IS_ERR(acl))
172 set_cached_acl(inode, type, acl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 return acl;
175}
176
177/*
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800178 * inode->i_mutex: down
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179 */
180static int
181ext2_set_acl(struct inode *inode, int type, struct posix_acl *acl)
182{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183 int name_index;
184 void *value = NULL;
Andreas Gruenbacherdfa08592006-02-03 03:04:13 -0800185 size_t size = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186 int error;
187
188 if (S_ISLNK(inode->i_mode))
189 return -EOPNOTSUPP;
190 if (!test_opt(inode->i_sb, POSIX_ACL))
191 return 0;
192
193 switch(type) {
194 case ACL_TYPE_ACCESS:
195 name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;
196 if (acl) {
197 mode_t mode = inode->i_mode;
198 error = posix_acl_equiv_mode(acl, &mode);
199 if (error < 0)
200 return error;
201 else {
202 inode->i_mode = mode;
Jan Kara523825b2010-06-02 16:26:51 +0200203 inode->i_ctime = CURRENT_TIME_SEC;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204 mark_inode_dirty(inode);
205 if (error == 0)
206 acl = NULL;
207 }
208 }
209 break;
210
211 case ACL_TYPE_DEFAULT:
212 name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT;
213 if (!S_ISDIR(inode->i_mode))
214 return acl ? -EACCES : 0;
215 break;
216
217 default:
218 return -EINVAL;
219 }
220 if (acl) {
221 value = ext2_acl_to_disk(acl, &size);
222 if (IS_ERR(value))
223 return (int)PTR_ERR(value);
224 }
225
226 error = ext2_xattr_set(inode, name_index, "", value, size, 0);
227
Jesper Juhlf99d49a2005-11-07 01:01:34 -0800228 kfree(value);
Al Viro073aaa12009-06-09 12:11:54 -0400229 if (!error)
230 set_cached_acl(inode, type, acl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231 return error;
232}
233
Linus Torvalds1d5ccd12009-08-28 12:12:24 -0700234int
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235ext2_check_acl(struct inode *inode, int mask)
236{
237 struct posix_acl *acl = ext2_get_acl(inode, ACL_TYPE_ACCESS);
238
akpm@osdl.orge4930732005-04-16 15:24:00 -0700239 if (IS_ERR(acl))
240 return PTR_ERR(acl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241 if (acl) {
242 int error = posix_acl_permission(inode, acl, mask);
243 posix_acl_release(acl);
244 return error;
245 }
246
247 return -EAGAIN;
248}
249
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250/*
251 * Initialize the ACLs of a new inode. Called from ext2_new_inode.
252 *
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800253 * dir->i_mutex: down
254 * inode->i_mutex: up (access to inode is still exclusive)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255 */
256int
257ext2_init_acl(struct inode *inode, struct inode *dir)
258{
259 struct posix_acl *acl = NULL;
260 int error = 0;
261
262 if (!S_ISLNK(inode->i_mode)) {
263 if (test_opt(dir->i_sb, POSIX_ACL)) {
264 acl = ext2_get_acl(dir, ACL_TYPE_DEFAULT);
265 if (IS_ERR(acl))
266 return PTR_ERR(acl);
267 }
268 if (!acl)
Al Viroce3b0f82009-03-29 19:08:22 -0400269 inode->i_mode &= ~current_umask();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270 }
271 if (test_opt(inode->i_sb, POSIX_ACL) && acl) {
272 struct posix_acl *clone;
273 mode_t mode;
274
275 if (S_ISDIR(inode->i_mode)) {
276 error = ext2_set_acl(inode, ACL_TYPE_DEFAULT, acl);
277 if (error)
278 goto cleanup;
279 }
280 clone = posix_acl_clone(acl, GFP_KERNEL);
281 error = -ENOMEM;
282 if (!clone)
283 goto cleanup;
284 mode = inode->i_mode;
285 error = posix_acl_create_masq(clone, &mode);
286 if (error >= 0) {
287 inode->i_mode = mode;
288 if (error > 0) {
289 /* This is an extended ACL */
290 error = ext2_set_acl(inode,
291 ACL_TYPE_ACCESS, clone);
292 }
293 }
294 posix_acl_release(clone);
295 }
296cleanup:
297 posix_acl_release(acl);
298 return error;
299}
300
301/*
302 * Does chmod for an inode that may have an Access Control List. The
303 * inode->i_mode field must be updated to the desired value by the caller
304 * before calling this function.
305 * Returns 0 on success, or a negative error number.
306 *
307 * We change the ACL rather than storing some ACL entries in the file
308 * mode permission bits (which would be more efficient), because that
309 * would break once additional permissions (like ACL_APPEND, ACL_DELETE
310 * for directories) are added. There are no more bits available in the
311 * file mode.
312 *
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800313 * inode->i_mutex: down
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314 */
315int
316ext2_acl_chmod(struct inode *inode)
317{
318 struct posix_acl *acl, *clone;
319 int error;
320
321 if (!test_opt(inode->i_sb, POSIX_ACL))
322 return 0;
323 if (S_ISLNK(inode->i_mode))
324 return -EOPNOTSUPP;
325 acl = ext2_get_acl(inode, ACL_TYPE_ACCESS);
326 if (IS_ERR(acl) || !acl)
327 return PTR_ERR(acl);
328 clone = posix_acl_clone(acl, GFP_KERNEL);
329 posix_acl_release(acl);
330 if (!clone)
331 return -ENOMEM;
332 error = posix_acl_chmod_masq(clone, inode->i_mode);
333 if (!error)
334 error = ext2_set_acl(inode, ACL_TYPE_ACCESS, clone);
335 posix_acl_release(clone);
336 return error;
337}
338
339/*
340 * Extended attribut handlers
341 */
342static size_t
Christoph Hellwig431547b2009-11-13 09:52:56 +0000343ext2_xattr_list_acl_access(struct dentry *dentry, char *list, size_t list_size,
344 const char *name, size_t name_len, int type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345{
Christoph Hellwig9a59f452005-06-23 00:10:19 -0700346 const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347
Christoph Hellwig431547b2009-11-13 09:52:56 +0000348 if (!test_opt(dentry->d_sb, POSIX_ACL))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349 return 0;
350 if (list && size <= list_size)
Christoph Hellwig9a59f452005-06-23 00:10:19 -0700351 memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700352 return size;
353}
354
355static size_t
Christoph Hellwig431547b2009-11-13 09:52:56 +0000356ext2_xattr_list_acl_default(struct dentry *dentry, char *list, size_t list_size,
357 const char *name, size_t name_len, int type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700358{
Christoph Hellwig9a59f452005-06-23 00:10:19 -0700359 const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360
Christoph Hellwig431547b2009-11-13 09:52:56 +0000361 if (!test_opt(dentry->d_sb, POSIX_ACL))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362 return 0;
363 if (list && size <= list_size)
Christoph Hellwig9a59f452005-06-23 00:10:19 -0700364 memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365 return size;
366}
367
368static int
Christoph Hellwig431547b2009-11-13 09:52:56 +0000369ext2_xattr_get_acl(struct dentry *dentry, const char *name, void *buffer,
370 size_t size, int type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371{
372 struct posix_acl *acl;
373 int error;
374
Christoph Hellwig431547b2009-11-13 09:52:56 +0000375 if (strcmp(name, "") != 0)
376 return -EINVAL;
377 if (!test_opt(dentry->d_sb, POSIX_ACL))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378 return -EOPNOTSUPP;
379
Christoph Hellwig431547b2009-11-13 09:52:56 +0000380 acl = ext2_get_acl(dentry->d_inode, type);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381 if (IS_ERR(acl))
382 return PTR_ERR(acl);
383 if (acl == NULL)
384 return -ENODATA;
385 error = posix_acl_to_xattr(acl, buffer, size);
386 posix_acl_release(acl);
387
388 return error;
389}
390
391static int
Christoph Hellwig431547b2009-11-13 09:52:56 +0000392ext2_xattr_set_acl(struct dentry *dentry, const char *name, const void *value,
393 size_t size, int flags, int type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394{
395 struct posix_acl *acl;
396 int error;
397
Christoph Hellwig431547b2009-11-13 09:52:56 +0000398 if (strcmp(name, "") != 0)
399 return -EINVAL;
400 if (!test_opt(dentry->d_sb, POSIX_ACL))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401 return -EOPNOTSUPP;
Christoph Hellwig431547b2009-11-13 09:52:56 +0000402 if (!is_owner_or_cap(dentry->d_inode))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403 return -EPERM;
404
405 if (value) {
406 acl = posix_acl_from_xattr(value, size);
407 if (IS_ERR(acl))
408 return PTR_ERR(acl);
409 else if (acl) {
410 error = posix_acl_valid(acl);
411 if (error)
412 goto release_and_out;
413 }
414 } else
415 acl = NULL;
416
Christoph Hellwig431547b2009-11-13 09:52:56 +0000417 error = ext2_set_acl(dentry->d_inode, type, acl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418
419release_and_out:
420 posix_acl_release(acl);
421 return error;
422}
423
Stephen Hemminger749c72e2010-05-13 17:53:16 -0700424const struct xattr_handler ext2_xattr_acl_access_handler = {
Christoph Hellwig9a59f452005-06-23 00:10:19 -0700425 .prefix = POSIX_ACL_XATTR_ACCESS,
Christoph Hellwig431547b2009-11-13 09:52:56 +0000426 .flags = ACL_TYPE_ACCESS,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427 .list = ext2_xattr_list_acl_access,
Christoph Hellwig431547b2009-11-13 09:52:56 +0000428 .get = ext2_xattr_get_acl,
429 .set = ext2_xattr_set_acl,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430};
431
Stephen Hemminger749c72e2010-05-13 17:53:16 -0700432const struct xattr_handler ext2_xattr_acl_default_handler = {
Christoph Hellwig9a59f452005-06-23 00:10:19 -0700433 .prefix = POSIX_ACL_XATTR_DEFAULT,
Christoph Hellwig431547b2009-11-13 09:52:56 +0000434 .flags = ACL_TYPE_DEFAULT,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435 .list = ext2_xattr_list_acl_default,
Christoph Hellwig431547b2009-11-13 09:52:56 +0000436 .get = ext2_xattr_get_acl,
437 .set = ext2_xattr_set_acl,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700438};