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1/*
2 * linux/fs/ext4/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 "ext4_jbd2.h"
13#include "ext4.h"
14#include "xattr.h"
15#include "acl.h"
16
17/*
18 * Convert from filesystem to in-memory representation.
19 */
20static struct posix_acl *
21ext4_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(ext4_acl_header))
30 return ERR_PTR(-EINVAL);
31 if (((ext4_acl_header *)value)->a_version !=
32 cpu_to_le32(EXT4_ACL_VERSION))
33 return ERR_PTR(-EINVAL);
34 value = (char *)value + sizeof(ext4_acl_header);
35 count = ext4_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 ext4_acl_entry *entry =
45 (ext4_acl_entry *)value;
46 if ((char *)value + sizeof(ext4_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
51 switch (acl->a_entries[n].e_tag) {
52 case ACL_USER_OBJ:
53 case ACL_GROUP_OBJ:
54 case ACL_MASK:
55 case ACL_OTHER:
56 value = (char *)value +
57 sizeof(ext4_acl_entry_short);
58 acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
59 break;
60
61 case ACL_USER:
62 case ACL_GROUP:
63 value = (char *)value + sizeof(ext4_acl_entry);
64 if ((char *)value > end)
65 goto fail;
66 acl->a_entries[n].e_id =
67 le32_to_cpu(entry->e_id);
68 break;
69
70 default:
71 goto fail;
72 }
73 }
74 if (value != end)
75 goto fail;
76 return acl;
77
78fail:
79 posix_acl_release(acl);
80 return ERR_PTR(-EINVAL);
81}
82
83/*
84 * Convert from in-memory to filesystem representation.
85 */
86static void *
87ext4_acl_to_disk(const struct posix_acl *acl, size_t *size)
88{
89 ext4_acl_header *ext_acl;
90 char *e;
91 size_t n;
92
93 *size = ext4_acl_size(acl->a_count);
94 ext_acl = kmalloc(sizeof(ext4_acl_header) + acl->a_count *
95 sizeof(ext4_acl_entry), GFP_NOFS);
96 if (!ext_acl)
97 return ERR_PTR(-ENOMEM);
98 ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION);
99 e = (char *)ext_acl + sizeof(ext4_acl_header);
100 for (n = 0; n < acl->a_count; n++) {
101 ext4_acl_entry *entry = (ext4_acl_entry *)e;
102 entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
103 entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
104 switch (acl->a_entries[n].e_tag) {
105 case ACL_USER:
106 case ACL_GROUP:
107 entry->e_id = cpu_to_le32(acl->a_entries[n].e_id);
108 e += sizeof(ext4_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(ext4_acl_entry_short);
116 break;
117
118 default:
119 goto fail;
120 }
121 }
122 return (char *)ext_acl;
123
124fail:
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 */
134struct posix_acl *
135ext4_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 = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
152 break;
153 case ACL_TYPE_DEFAULT:
154 name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
155 break;
156 default:
157 BUG();
158 }
159 retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
160 if (retval > 0) {
161 value = kmalloc(retval, GFP_NOFS);
162 if (!value)
163 return ERR_PTR(-ENOMEM);
164 retval = ext4_xattr_get(inode, name_index, "", value, retval);
165 }
166 if (retval > 0)
167 acl = ext4_acl_from_disk(value, retval);
168 else if (retval == -ENODATA || retval == -ENOSYS)
169 acl = NULL;
170 else
171 acl = ERR_PTR(retval);
172 kfree(value);
173
174 if (!IS_ERR(acl))
175 set_cached_acl(inode, type, acl);
176
177 return acl;
178}
179
180/*
181 * Set the access or default ACL of an inode.
182 *
183 * inode->i_mutex: down unless called from ext4_new_inode
184 */
185static int
186ext4_set_acl(handle_t *handle, struct inode *inode, int type,
187 struct posix_acl *acl)
188{
189 int name_index;
190 void *value = NULL;
191 size_t size = 0;
192 int error;
193
194 if (S_ISLNK(inode->i_mode))
195 return -EOPNOTSUPP;
196
197 switch (type) {
198 case ACL_TYPE_ACCESS:
199 name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
200 if (acl) {
201 error = posix_acl_equiv_mode(acl, &inode->i_mode);
202 if (error < 0)
203 return error;
204 else {
205 inode->i_ctime = ext4_current_time(inode);
206 ext4_mark_inode_dirty(handle, inode);
207 if (error == 0)
208 acl = NULL;
209 }
210 }
211 break;
212
213 case ACL_TYPE_DEFAULT:
214 name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
215 if (!S_ISDIR(inode->i_mode))
216 return acl ? -EACCES : 0;
217 break;
218
219 default:
220 return -EINVAL;
221 }
222 if (acl) {
223 value = ext4_acl_to_disk(acl, &size);
224 if (IS_ERR(value))
225 return (int)PTR_ERR(value);
226 }
227
228 error = ext4_xattr_set_handle(handle, inode, name_index, "",
229 value, size, 0);
230
231 kfree(value);
232 if (!error)
233 set_cached_acl(inode, type, acl);
234
235 return error;
236}
237
238/*
239 * Initialize the ACLs of a new inode. Called from ext4_new_inode.
240 *
241 * dir->i_mutex: down
242 * inode->i_mutex: up (access to inode is still exclusive)
243 */
244int
245ext4_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)
246{
247 struct posix_acl *acl = NULL;
248 int error = 0;
249
250 if (!S_ISLNK(inode->i_mode)) {
251 if (test_opt(dir->i_sb, POSIX_ACL)) {
252 acl = ext4_get_acl(dir, ACL_TYPE_DEFAULT);
253 if (IS_ERR(acl))
254 return PTR_ERR(acl);
255 }
256 if (!acl)
257 inode->i_mode &= ~current_umask();
258 }
259 if (test_opt(inode->i_sb, POSIX_ACL) && acl) {
260 if (S_ISDIR(inode->i_mode)) {
261 error = ext4_set_acl(handle, inode,
262 ACL_TYPE_DEFAULT, acl);
263 if (error)
264 goto cleanup;
265 }
266 error = posix_acl_create(&acl, GFP_NOFS, &inode->i_mode);
267 if (error < 0)
268 return error;
269
270 if (error > 0) {
271 /* This is an extended ACL */
272 error = ext4_set_acl(handle, inode, ACL_TYPE_ACCESS, acl);
273 }
274 }
275cleanup:
276 posix_acl_release(acl);
277 return error;
278}
279
280/*
281 * Does chmod for an inode that may have an Access Control List. The
282 * inode->i_mode field must be updated to the desired value by the caller
283 * before calling this function.
284 * Returns 0 on success, or a negative error number.
285 *
286 * We change the ACL rather than storing some ACL entries in the file
287 * mode permission bits (which would be more efficient), because that
288 * would break once additional permissions (like ACL_APPEND, ACL_DELETE
289 * for directories) are added. There are no more bits available in the
290 * file mode.
291 *
292 * inode->i_mutex: down
293 */
294int
295ext4_acl_chmod(struct inode *inode)
296{
297 struct posix_acl *acl;
298 handle_t *handle;
299 int retries = 0;
300 int error;
301
302
303 if (S_ISLNK(inode->i_mode))
304 return -EOPNOTSUPP;
305 if (!test_opt(inode->i_sb, POSIX_ACL))
306 return 0;
307 acl = ext4_get_acl(inode, ACL_TYPE_ACCESS);
308 if (IS_ERR(acl) || !acl)
309 return PTR_ERR(acl);
310 error = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
311 if (error)
312 return error;
313retry:
314 handle = ext4_journal_start(inode,
315 EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
316 if (IS_ERR(handle)) {
317 error = PTR_ERR(handle);
318 ext4_std_error(inode->i_sb, error);
319 goto out;
320 }
321 error = ext4_set_acl(handle, inode, ACL_TYPE_ACCESS, acl);
322 ext4_journal_stop(handle);
323 if (error == -ENOSPC &&
324 ext4_should_retry_alloc(inode->i_sb, &retries))
325 goto retry;
326out:
327 posix_acl_release(acl);
328 return error;
329}
330
331/*
332 * Extended attribute handlers
333 */
334static size_t
335ext4_xattr_list_acl_access(struct dentry *dentry, char *list, size_t list_len,
336 const char *name, size_t name_len, int type)
337{
338 const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
339
340 if (!test_opt(dentry->d_sb, POSIX_ACL))
341 return 0;
342 if (list && size <= list_len)
343 memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
344 return size;
345}
346
347static size_t
348ext4_xattr_list_acl_default(struct dentry *dentry, char *list, size_t list_len,
349 const char *name, size_t name_len, int type)
350{
351 const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
352
353 if (!test_opt(dentry->d_sb, POSIX_ACL))
354 return 0;
355 if (list && size <= list_len)
356 memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
357 return size;
358}
359
360static int
361ext4_xattr_get_acl(struct dentry *dentry, const char *name, void *buffer,
362 size_t size, int type)
363{
364 struct posix_acl *acl;
365 int error;
366
367 if (strcmp(name, "") != 0)
368 return -EINVAL;
369 if (!test_opt(dentry->d_sb, POSIX_ACL))
370 return -EOPNOTSUPP;
371
372 acl = ext4_get_acl(dentry->d_inode, type);
373 if (IS_ERR(acl))
374 return PTR_ERR(acl);
375 if (acl == NULL)
376 return -ENODATA;
377 error = posix_acl_to_xattr(acl, buffer, size);
378 posix_acl_release(acl);
379
380 return error;
381}
382
383static int
384ext4_xattr_set_acl(struct dentry *dentry, const char *name, const void *value,
385 size_t size, int flags, int type)
386{
387 struct inode *inode = dentry->d_inode;
388 handle_t *handle;
389 struct posix_acl *acl;
390 int error, retries = 0;
391
392 if (strcmp(name, "") != 0)
393 return -EINVAL;
394 if (!test_opt(inode->i_sb, POSIX_ACL))
395 return -EOPNOTSUPP;
396 if (!inode_owner_or_capable(inode))
397 return -EPERM;
398
399 if (value) {
400 acl = posix_acl_from_xattr(value, size);
401 if (IS_ERR(acl))
402 return PTR_ERR(acl);
403 else if (acl) {
404 error = posix_acl_valid(acl);
405 if (error)
406 goto release_and_out;
407 }
408 } else
409 acl = NULL;
410
411retry:
412 handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
413 if (IS_ERR(handle))
414 return PTR_ERR(handle);
415 error = ext4_set_acl(handle, inode, type, acl);
416 ext4_journal_stop(handle);
417 if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
418 goto retry;
419
420release_and_out:
421 posix_acl_release(acl);
422 return error;
423}
424
425const struct xattr_handler ext4_xattr_acl_access_handler = {
426 .prefix = POSIX_ACL_XATTR_ACCESS,
427 .flags = ACL_TYPE_ACCESS,
428 .list = ext4_xattr_list_acl_access,
429 .get = ext4_xattr_get_acl,
430 .set = ext4_xattr_set_acl,
431};
432
433const struct xattr_handler ext4_xattr_acl_default_handler = {
434 .prefix = POSIX_ACL_XATTR_DEFAULT,
435 .flags = ACL_TYPE_DEFAULT,
436 .list = ext4_xattr_list_acl_default,
437 .get = ext4_xattr_get_acl,
438 .set = ext4_xattr_set_acl,
439};
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/fs/ext4/acl.c
4 *
5 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
6 */
7
8#include <linux/quotaops.h>
9#include "ext4_jbd2.h"
10#include "ext4.h"
11#include "xattr.h"
12#include "acl.h"
13
14/*
15 * Convert from filesystem to in-memory representation.
16 */
17static struct posix_acl *
18ext4_acl_from_disk(const void *value, size_t size)
19{
20 const char *end = (char *)value + size;
21 int n, count;
22 struct posix_acl *acl;
23
24 if (!value)
25 return NULL;
26 if (size < sizeof(ext4_acl_header))
27 return ERR_PTR(-EINVAL);
28 if (((ext4_acl_header *)value)->a_version !=
29 cpu_to_le32(EXT4_ACL_VERSION))
30 return ERR_PTR(-EINVAL);
31 value = (char *)value + sizeof(ext4_acl_header);
32 count = ext4_acl_count(size);
33 if (count < 0)
34 return ERR_PTR(-EINVAL);
35 if (count == 0)
36 return NULL;
37 acl = posix_acl_alloc(count, GFP_NOFS);
38 if (!acl)
39 return ERR_PTR(-ENOMEM);
40 for (n = 0; n < count; n++) {
41 ext4_acl_entry *entry =
42 (ext4_acl_entry *)value;
43 if ((char *)value + sizeof(ext4_acl_entry_short) > end)
44 goto fail;
45 acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
46 acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
47
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(ext4_acl_entry_short);
55 break;
56
57 case ACL_USER:
58 value = (char *)value + sizeof(ext4_acl_entry);
59 if ((char *)value > end)
60 goto fail;
61 acl->a_entries[n].e_uid =
62 make_kuid(&init_user_ns,
63 le32_to_cpu(entry->e_id));
64 break;
65 case ACL_GROUP:
66 value = (char *)value + sizeof(ext4_acl_entry);
67 if ((char *)value > end)
68 goto fail;
69 acl->a_entries[n].e_gid =
70 make_kgid(&init_user_ns,
71 le32_to_cpu(entry->e_id));
72 break;
73
74 default:
75 goto fail;
76 }
77 }
78 if (value != end)
79 goto fail;
80 return acl;
81
82fail:
83 posix_acl_release(acl);
84 return ERR_PTR(-EINVAL);
85}
86
87/*
88 * Convert from in-memory to filesystem representation.
89 */
90static void *
91ext4_acl_to_disk(const struct posix_acl *acl, size_t *size)
92{
93 ext4_acl_header *ext_acl;
94 char *e;
95 size_t n;
96
97 *size = ext4_acl_size(acl->a_count);
98 ext_acl = kmalloc(sizeof(ext4_acl_header) + acl->a_count *
99 sizeof(ext4_acl_entry), GFP_NOFS);
100 if (!ext_acl)
101 return ERR_PTR(-ENOMEM);
102 ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION);
103 e = (char *)ext_acl + sizeof(ext4_acl_header);
104 for (n = 0; n < acl->a_count; n++) {
105 const struct posix_acl_entry *acl_e = &acl->a_entries[n];
106 ext4_acl_entry *entry = (ext4_acl_entry *)e;
107 entry->e_tag = cpu_to_le16(acl_e->e_tag);
108 entry->e_perm = cpu_to_le16(acl_e->e_perm);
109 switch (acl_e->e_tag) {
110 case ACL_USER:
111 entry->e_id = cpu_to_le32(
112 from_kuid(&init_user_ns, acl_e->e_uid));
113 e += sizeof(ext4_acl_entry);
114 break;
115 case ACL_GROUP:
116 entry->e_id = cpu_to_le32(
117 from_kgid(&init_user_ns, acl_e->e_gid));
118 e += sizeof(ext4_acl_entry);
119 break;
120
121 case ACL_USER_OBJ:
122 case ACL_GROUP_OBJ:
123 case ACL_MASK:
124 case ACL_OTHER:
125 e += sizeof(ext4_acl_entry_short);
126 break;
127
128 default:
129 goto fail;
130 }
131 }
132 return (char *)ext_acl;
133
134fail:
135 kfree(ext_acl);
136 return ERR_PTR(-EINVAL);
137}
138
139/*
140 * Inode operation get_posix_acl().
141 *
142 * inode->i_rwsem: don't care
143 */
144struct posix_acl *
145ext4_get_acl(struct inode *inode, int type, bool rcu)
146{
147 int name_index;
148 char *value = NULL;
149 struct posix_acl *acl;
150 int retval;
151
152 if (rcu)
153 return ERR_PTR(-ECHILD);
154
155 switch (type) {
156 case ACL_TYPE_ACCESS:
157 name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
158 break;
159 case ACL_TYPE_DEFAULT:
160 name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
161 break;
162 default:
163 BUG();
164 }
165 retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
166 if (retval > 0) {
167 value = kmalloc(retval, GFP_NOFS);
168 if (!value)
169 return ERR_PTR(-ENOMEM);
170 retval = ext4_xattr_get(inode, name_index, "", value, retval);
171 }
172 if (retval > 0)
173 acl = ext4_acl_from_disk(value, retval);
174 else if (retval == -ENODATA || retval == -ENOSYS)
175 acl = NULL;
176 else
177 acl = ERR_PTR(retval);
178 kfree(value);
179
180 return acl;
181}
182
183/*
184 * Set the access or default ACL of an inode.
185 *
186 * inode->i_rwsem: down unless called from ext4_new_inode
187 */
188static int
189__ext4_set_acl(handle_t *handle, struct inode *inode, int type,
190 struct posix_acl *acl, int xattr_flags)
191{
192 int name_index;
193 void *value = NULL;
194 size_t size = 0;
195 int error;
196
197 switch (type) {
198 case ACL_TYPE_ACCESS:
199 name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
200 break;
201
202 case ACL_TYPE_DEFAULT:
203 name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
204 if (!S_ISDIR(inode->i_mode))
205 return acl ? -EACCES : 0;
206 break;
207
208 default:
209 return -EINVAL;
210 }
211 if (acl) {
212 value = ext4_acl_to_disk(acl, &size);
213 if (IS_ERR(value))
214 return (int)PTR_ERR(value);
215 }
216
217 error = ext4_xattr_set_handle(handle, inode, name_index, "",
218 value, size, xattr_flags);
219
220 kfree(value);
221 if (!error)
222 set_cached_acl(inode, type, acl);
223
224 return error;
225}
226
227int
228ext4_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
229 struct posix_acl *acl, int type)
230{
231 handle_t *handle;
232 int error, credits, retries = 0;
233 size_t acl_size = acl ? ext4_acl_size(acl->a_count) : 0;
234 struct inode *inode = d_inode(dentry);
235 umode_t mode = inode->i_mode;
236 int update_mode = 0;
237
238 error = dquot_initialize(inode);
239 if (error)
240 return error;
241retry:
242 error = ext4_xattr_set_credits(inode, acl_size, false /* is_create */,
243 &credits);
244 if (error)
245 return error;
246
247 handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
248 if (IS_ERR(handle))
249 return PTR_ERR(handle);
250
251 if ((type == ACL_TYPE_ACCESS) && acl) {
252 error = posix_acl_update_mode(idmap, inode, &mode, &acl);
253 if (error)
254 goto out_stop;
255 if (mode != inode->i_mode)
256 update_mode = 1;
257 }
258
259 error = __ext4_set_acl(handle, inode, type, acl, 0 /* xattr_flags */);
260 if (!error && update_mode) {
261 inode->i_mode = mode;
262 inode_set_ctime_current(inode);
263 error = ext4_mark_inode_dirty(handle, inode);
264 }
265out_stop:
266 ext4_journal_stop(handle);
267 if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
268 goto retry;
269 return error;
270}
271
272/*
273 * Initialize the ACLs of a new inode. Called from ext4_new_inode.
274 *
275 * dir->i_rwsem: down
276 * inode->i_rwsem: up (access to inode is still exclusive)
277 */
278int
279ext4_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)
280{
281 struct posix_acl *default_acl, *acl;
282 int error;
283
284 error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
285 if (error)
286 return error;
287
288 if (default_acl) {
289 error = __ext4_set_acl(handle, inode, ACL_TYPE_DEFAULT,
290 default_acl, XATTR_CREATE);
291 posix_acl_release(default_acl);
292 } else {
293 inode->i_default_acl = NULL;
294 }
295 if (acl) {
296 if (!error)
297 error = __ext4_set_acl(handle, inode, ACL_TYPE_ACCESS,
298 acl, XATTR_CREATE);
299 posix_acl_release(acl);
300 } else {
301 inode->i_acl = NULL;
302 }
303 return error;
304}