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