1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * fs/f2fs/acl.c
4 *
5 * Copyright (c) 2012 Samsung Electronics Co., Ltd.
6 * http://www.samsung.com/
7 *
8 * Portions of this code from linux/fs/ext2/acl.c
9 *
10 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
11 */
12 #include <linux/f2fs_fs.h>
13 #include "f2fs.h"
14 #include "xattr.h"
15 #include "acl.h"
16
17 static inline size_t f2fs_acl_size(int count)
18 {
19 if (count <= 4) {
20 return sizeof(struct f2fs_acl_header) +
21 count * sizeof(struct f2fs_acl_entry_short);
22 } else {
23 return sizeof(struct f2fs_acl_header) +
24 4 * sizeof(struct f2fs_acl_entry_short) +
25 (count - 4) * sizeof(struct f2fs_acl_entry);
26 }
27 }
28
29 static inline int f2fs_acl_count(size_t size)
30 {
31 ssize_t s;
32
33 size -= sizeof(struct f2fs_acl_header);
34 s = size - 4 * sizeof(struct f2fs_acl_entry_short);
35 if (s < 0) {
36 if (size % sizeof(struct f2fs_acl_entry_short))
37 return -1;
38 return size / sizeof(struct f2fs_acl_entry_short);
39 } else {
40 if (s % sizeof(struct f2fs_acl_entry))
41 return -1;
42 return s / sizeof(struct f2fs_acl_entry) + 4;
43 }
44 }
45
46 static struct posix_acl *f2fs_acl_from_disk(const char *value, size_t size)
47 {
48 int i, count;
49 struct posix_acl *acl;
50 struct f2fs_acl_header *hdr = (struct f2fs_acl_header *)value;
51 struct f2fs_acl_entry *entry = (struct f2fs_acl_entry *)(hdr + 1);
52 const char *end = value + size;
53
54 if (size < sizeof(struct f2fs_acl_header))
55 return ERR_PTR(-EINVAL);
56
57 if (hdr->a_version != cpu_to_le32(F2FS_ACL_VERSION))
58 return ERR_PTR(-EINVAL);
59
60 count = f2fs_acl_count(size);
61 if (count < 0)
62 return ERR_PTR(-EINVAL);
63 if (count == 0)
64 return NULL;
65
66 acl = posix_acl_alloc(count, GFP_NOFS);
67 if (!acl)
68 return ERR_PTR(-ENOMEM);
69
70 for (i = 0; i < count; i++) {
71
72 if ((char *)entry > end)
73 goto fail;
74
75 acl->a_entries[i].e_tag = le16_to_cpu(entry->e_tag);
76 acl->a_entries[i].e_perm = le16_to_cpu(entry->e_perm);
77
78 switch (acl->a_entries[i].e_tag) {
79 case ACL_USER_OBJ:
80 case ACL_GROUP_OBJ:
81 case ACL_MASK:
82 case ACL_OTHER:
83 entry = (struct f2fs_acl_entry *)((char *)entry +
84 sizeof(struct f2fs_acl_entry_short));
85 break;
86
87 case ACL_USER:
88 acl->a_entries[i].e_uid =
89 make_kuid(&init_user_ns,
90 le32_to_cpu(entry->e_id));
91 entry = (struct f2fs_acl_entry *)((char *)entry +
92 sizeof(struct f2fs_acl_entry));
93 break;
94 case ACL_GROUP:
95 acl->a_entries[i].e_gid =
96 make_kgid(&init_user_ns,
97 le32_to_cpu(entry->e_id));
98 entry = (struct f2fs_acl_entry *)((char *)entry +
99 sizeof(struct f2fs_acl_entry));
100 break;
101 default:
102 goto fail;
103 }
104 }
105 if ((char *)entry != end)
106 goto fail;
107 return acl;
108 fail:
109 posix_acl_release(acl);
110 return ERR_PTR(-EINVAL);
111 }
112
113 static void *f2fs_acl_to_disk(struct f2fs_sb_info *sbi,
114 const struct posix_acl *acl, size_t *size)
115 {
116 struct f2fs_acl_header *f2fs_acl;
117 struct f2fs_acl_entry *entry;
118 int i;
119
120 f2fs_acl = f2fs_kmalloc(sbi, sizeof(struct f2fs_acl_header) +
121 acl->a_count * sizeof(struct f2fs_acl_entry),
122 GFP_NOFS);
123 if (!f2fs_acl)
124 return ERR_PTR(-ENOMEM);
125
126 f2fs_acl->a_version = cpu_to_le32(F2FS_ACL_VERSION);
127 entry = (struct f2fs_acl_entry *)(f2fs_acl + 1);
128
129 for (i = 0; i < acl->a_count; i++) {
130
131 entry->e_tag = cpu_to_le16(acl->a_entries[i].e_tag);
132 entry->e_perm = cpu_to_le16(acl->a_entries[i].e_perm);
133
134 switch (acl->a_entries[i].e_tag) {
135 case ACL_USER:
136 entry->e_id = cpu_to_le32(
137 from_kuid(&init_user_ns,
138 acl->a_entries[i].e_uid));
139 entry = (struct f2fs_acl_entry *)((char *)entry +
140 sizeof(struct f2fs_acl_entry));
141 break;
142 case ACL_GROUP:
143 entry->e_id = cpu_to_le32(
144 from_kgid(&init_user_ns,
145 acl->a_entries[i].e_gid));
146 entry = (struct f2fs_acl_entry *)((char *)entry +
147 sizeof(struct f2fs_acl_entry));
148 break;
149 case ACL_USER_OBJ:
150 case ACL_GROUP_OBJ:
151 case ACL_MASK:
152 case ACL_OTHER:
153 entry = (struct f2fs_acl_entry *)((char *)entry +
154 sizeof(struct f2fs_acl_entry_short));
155 break;
156 default:
157 goto fail;
158 }
159 }
160 *size = f2fs_acl_size(acl->a_count);
161 return (void *)f2fs_acl;
162
163 fail:
164 kfree(f2fs_acl);
165 return ERR_PTR(-EINVAL);
166 }
167
168 static struct posix_acl *__f2fs_get_acl(struct inode *inode, int type,
169 struct page *dpage)
170 {
171 int name_index = F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT;
172 void *value = NULL;
173 struct posix_acl *acl;
174 int retval;
175
176 if (type == ACL_TYPE_ACCESS)
177 name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS;
178
179 retval = f2fs_getxattr(inode, name_index, "", NULL, 0, dpage);
180 if (retval > 0) {
181 value = f2fs_kmalloc(F2FS_I_SB(inode), retval, GFP_F2FS_ZERO);
182 if (!value)
183 return ERR_PTR(-ENOMEM);
184 retval = f2fs_getxattr(inode, name_index, "", value,
185 retval, dpage);
186 }
187
188 if (retval > 0)
189 acl = f2fs_acl_from_disk(value, retval);
190 else if (retval == -ENODATA)
191 acl = NULL;
192 else
193 acl = ERR_PTR(retval);
194 kfree(value);
195
196 return acl;
197 }
198
199 struct posix_acl *f2fs_get_acl(struct inode *inode, int type, bool rcu)
200 {
201 if (rcu)
202 return ERR_PTR(-ECHILD);
203
204 return __f2fs_get_acl(inode, type, NULL);
205 }
206
207 static int f2fs_acl_update_mode(struct mnt_idmap *idmap,
208 struct inode *inode, umode_t *mode_p,
209 struct posix_acl **acl)
210 {
211 umode_t mode = inode->i_mode;
212 int error;
213
214 if (is_inode_flag_set(inode, FI_ACL_MODE))
215 mode = F2FS_I(inode)->i_acl_mode;
216
217 error = posix_acl_equiv_mode(*acl, &mode);
218 if (error < 0)
219 return error;
220 if (error == 0)
221 *acl = NULL;
222 if (!in_group_or_capable(idmap, inode, i_gid_into_vfsgid(idmap, inode)))
223 mode &= ~S_ISGID;
224 *mode_p = mode;
225 return 0;
226 }
227
228 static int __f2fs_set_acl(struct mnt_idmap *idmap,
229 struct inode *inode, int type,
230 struct posix_acl *acl, struct page *ipage)
231 {
232 int name_index;
233 void *value = NULL;
234 size_t size = 0;
235 int error;
236 umode_t mode = inode->i_mode;
237
238 switch (type) {
239 case ACL_TYPE_ACCESS:
240 name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS;
241 if (acl && !ipage) {
242 error = f2fs_acl_update_mode(idmap, inode,
243 &mode, &acl);
244 if (error)
245 return error;
246 set_acl_inode(inode, mode);
247 }
248 break;
249
250 case ACL_TYPE_DEFAULT:
251 name_index = F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT;
252 if (!S_ISDIR(inode->i_mode))
253 return acl ? -EACCES : 0;
254 break;
255
256 default:
257 return -EINVAL;
258 }
259
260 if (acl) {
261 value = f2fs_acl_to_disk(F2FS_I_SB(inode), acl, &size);
262 if (IS_ERR(value)) {
263 clear_inode_flag(inode, FI_ACL_MODE);
264 return PTR_ERR(value);
265 }
266 }
267
268 error = f2fs_setxattr(inode, name_index, "", value, size, ipage, 0);
269
270 kfree(value);
271 if (!error)
272 set_cached_acl(inode, type, acl);
273
274 clear_inode_flag(inode, FI_ACL_MODE);
275 return error;
276 }
277
278 int f2fs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
279 struct posix_acl *acl, int type)
280 {
281 struct inode *inode = d_inode(dentry);
282
283 if (unlikely(f2fs_cp_error(F2FS_I_SB(inode))))
284 return -EIO;
285
286 return __f2fs_set_acl(idmap, inode, type, acl, NULL);
287 }
288
289 /*
290 * Most part of f2fs_acl_clone, f2fs_acl_create_masq, f2fs_acl_create
291 * are copied from posix_acl.c
292 */
293 static struct posix_acl *f2fs_acl_clone(const struct posix_acl *acl,
294 gfp_t flags)
295 {
296 struct posix_acl *clone = NULL;
297
298 if (acl) {
299 int size = sizeof(struct posix_acl) + acl->a_count *
300 sizeof(struct posix_acl_entry);
301 clone = kmemdup(acl, size, flags);
302 if (clone)
303 refcount_set(&clone->a_refcount, 1);
304 }
305 return clone;
306 }
307
308 static int f2fs_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)
309 {
310 struct posix_acl_entry *pa, *pe;
311 struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
312 umode_t mode = *mode_p;
313 int not_equiv = 0;
314
315 /* assert(atomic_read(acl->a_refcount) == 1); */
316
317 FOREACH_ACL_ENTRY(pa, acl, pe) {
318 switch (pa->e_tag) {
319 case ACL_USER_OBJ:
320 pa->e_perm &= (mode >> 6) | ~S_IRWXO;
321 mode &= (pa->e_perm << 6) | ~S_IRWXU;
322 break;
323
324 case ACL_USER:
325 case ACL_GROUP:
326 not_equiv = 1;
327 break;
328
329 case ACL_GROUP_OBJ:
330 group_obj = pa;
331 break;
332
333 case ACL_OTHER:
334 pa->e_perm &= mode | ~S_IRWXO;
335 mode &= pa->e_perm | ~S_IRWXO;
336 break;
337
338 case ACL_MASK:
339 mask_obj = pa;
340 not_equiv = 1;
341 break;
342
343 default:
344 return -EIO;
345 }
346 }
347
348 if (mask_obj) {
349 mask_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
350 mode &= (mask_obj->e_perm << 3) | ~S_IRWXG;
351 } else {
352 if (!group_obj)
353 return -EIO;
354 group_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
355 mode &= (group_obj->e_perm << 3) | ~S_IRWXG;
356 }
357
358 *mode_p = (*mode_p & ~S_IRWXUGO) | mode;
359 return not_equiv;
360 }
361
362 static int f2fs_acl_create(struct inode *dir, umode_t *mode,
363 struct posix_acl **default_acl, struct posix_acl **acl,
364 struct page *dpage)
365 {
366 struct posix_acl *p;
367 struct posix_acl *clone;
368 int ret;
369
370 *acl = NULL;
371 *default_acl = NULL;
372
373 if (S_ISLNK(*mode) || !IS_POSIXACL(dir))
374 return 0;
375
376 p = __f2fs_get_acl(dir, ACL_TYPE_DEFAULT, dpage);
377 if (!p || p == ERR_PTR(-EOPNOTSUPP)) {
378 *mode &= ~current_umask();
379 return 0;
380 }
381 if (IS_ERR(p))
382 return PTR_ERR(p);
383
384 clone = f2fs_acl_clone(p, GFP_NOFS);
385 if (!clone) {
386 ret = -ENOMEM;
387 goto release_acl;
388 }
389
390 ret = f2fs_acl_create_masq(clone, mode);
391 if (ret < 0)
392 goto release_clone;
393
394 if (ret == 0)
395 posix_acl_release(clone);
396 else
397 *acl = clone;
398
399 if (!S_ISDIR(*mode))
400 posix_acl_release(p);
401 else
402 *default_acl = p;
403
404 return 0;
405
406 release_clone:
407 posix_acl_release(clone);
408 release_acl:
409 posix_acl_release(p);
410 return ret;
411 }
412
413 int f2fs_init_acl(struct inode *inode, struct inode *dir, struct page *ipage,
414 struct page *dpage)
415 {
416 struct posix_acl *default_acl = NULL, *acl = NULL;
417 int error;
418
419 error = f2fs_acl_create(dir, &inode->i_mode, &default_acl, &acl, dpage);
420 if (error)
421 return error;
422
423 f2fs_mark_inode_dirty_sync(inode, true);
424
425 if (default_acl) {
426 error = __f2fs_set_acl(NULL, inode, ACL_TYPE_DEFAULT, default_acl,
427 ipage);
428 posix_acl_release(default_acl);
429 } else {
430 inode->i_default_acl = NULL;
431 }
432 if (acl) {
433 if (!error)
434 error = __f2fs_set_acl(NULL, inode, ACL_TYPE_ACCESS, acl,
435 ipage);
436 posix_acl_release(acl);
437 } else {
438 inode->i_acl = NULL;
439 }
440
441 return error;
442 }
443
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