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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2007 Red Hat. All rights reserved.
4 */
5
6#include <linux/fs.h>
7#include <linux/string.h>
8#include <linux/xattr.h>
9#include <linux/posix_acl_xattr.h>
10#include <linux/posix_acl.h>
11#include <linux/sched.h>
12#include <linux/sched/mm.h>
13#include <linux/slab.h>
14
15#include "ctree.h"
16#include "btrfs_inode.h"
17#include "xattr.h"
18
19struct posix_acl *btrfs_get_acl(struct inode *inode, int type)
20{
21 int size;
22 const char *name;
23 char *value = NULL;
24 struct posix_acl *acl;
25
26 switch (type) {
27 case ACL_TYPE_ACCESS:
28 name = XATTR_NAME_POSIX_ACL_ACCESS;
29 break;
30 case ACL_TYPE_DEFAULT:
31 name = XATTR_NAME_POSIX_ACL_DEFAULT;
32 break;
33 default:
34 return ERR_PTR(-EINVAL);
35 }
36
37 size = btrfs_getxattr(inode, name, NULL, 0);
38 if (size > 0) {
39 value = kzalloc(size, GFP_KERNEL);
40 if (!value)
41 return ERR_PTR(-ENOMEM);
42 size = btrfs_getxattr(inode, name, value, size);
43 }
44 if (size > 0)
45 acl = posix_acl_from_xattr(&init_user_ns, value, size);
46 else if (size == -ENODATA || size == 0)
47 acl = NULL;
48 else
49 acl = ERR_PTR(size);
50 kfree(value);
51
52 return acl;
53}
54
55static int __btrfs_set_acl(struct btrfs_trans_handle *trans,
56 struct inode *inode, struct posix_acl *acl, int type)
57{
58 int ret, size = 0;
59 const char *name;
60 char *value = NULL;
61
62 switch (type) {
63 case ACL_TYPE_ACCESS:
64 name = XATTR_NAME_POSIX_ACL_ACCESS;
65 break;
66 case ACL_TYPE_DEFAULT:
67 if (!S_ISDIR(inode->i_mode))
68 return acl ? -EINVAL : 0;
69 name = XATTR_NAME_POSIX_ACL_DEFAULT;
70 break;
71 default:
72 return -EINVAL;
73 }
74
75 if (acl) {
76 unsigned int nofs_flag;
77
78 size = posix_acl_xattr_size(acl->a_count);
79 /*
80 * We're holding a transaction handle, so use a NOFS memory
81 * allocation context to avoid deadlock if reclaim happens.
82 */
83 nofs_flag = memalloc_nofs_save();
84 value = kmalloc(size, GFP_KERNEL);
85 memalloc_nofs_restore(nofs_flag);
86 if (!value) {
87 ret = -ENOMEM;
88 goto out;
89 }
90
91 ret = posix_acl_to_xattr(&init_user_ns, acl, value, size);
92 if (ret < 0)
93 goto out;
94 }
95
96 if (trans)
97 ret = btrfs_setxattr(trans, inode, name, value, size, 0);
98 else
99 ret = btrfs_setxattr_trans(inode, name, value, size, 0);
100
101out:
102 kfree(value);
103
104 if (!ret)
105 set_cached_acl(inode, type, acl);
106
107 return ret;
108}
109
110int btrfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
111{
112 int ret;
113 umode_t old_mode = inode->i_mode;
114
115 if (type == ACL_TYPE_ACCESS && acl) {
116 ret = posix_acl_update_mode(inode, &inode->i_mode, &acl);
117 if (ret)
118 return ret;
119 }
120 ret = __btrfs_set_acl(NULL, inode, acl, type);
121 if (ret)
122 inode->i_mode = old_mode;
123 return ret;
124}
125
126int btrfs_init_acl(struct btrfs_trans_handle *trans,
127 struct inode *inode, struct inode *dir)
128{
129 struct posix_acl *default_acl, *acl;
130 int ret = 0;
131
132 /* this happens with subvols */
133 if (!dir)
134 return 0;
135
136 ret = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
137 if (ret)
138 return ret;
139
140 if (default_acl) {
141 ret = __btrfs_set_acl(trans, inode, default_acl,
142 ACL_TYPE_DEFAULT);
143 posix_acl_release(default_acl);
144 }
145
146 if (acl) {
147 if (!ret)
148 ret = __btrfs_set_acl(trans, inode, acl,
149 ACL_TYPE_ACCESS);
150 posix_acl_release(acl);
151 }
152
153 if (!default_acl && !acl)
154 cache_no_acl(inode);
155 return ret;
156}
1/*
2 * Copyright (C) 2007 Red Hat. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19#include <linux/fs.h>
20#include <linux/string.h>
21#include <linux/xattr.h>
22#include <linux/posix_acl_xattr.h>
23#include <linux/posix_acl.h>
24#include <linux/sched.h>
25#include <linux/slab.h>
26
27#include "ctree.h"
28#include "btrfs_inode.h"
29#include "xattr.h"
30
31struct posix_acl *btrfs_get_acl(struct inode *inode, int type)
32{
33 int size;
34 const char *name;
35 char *value = NULL;
36 struct posix_acl *acl;
37
38 if (!IS_POSIXACL(inode))
39 return NULL;
40
41 acl = get_cached_acl(inode, type);
42 if (acl != ACL_NOT_CACHED)
43 return acl;
44
45 switch (type) {
46 case ACL_TYPE_ACCESS:
47 name = POSIX_ACL_XATTR_ACCESS;
48 break;
49 case ACL_TYPE_DEFAULT:
50 name = POSIX_ACL_XATTR_DEFAULT;
51 break;
52 default:
53 BUG();
54 }
55
56 size = __btrfs_getxattr(inode, name, "", 0);
57 if (size > 0) {
58 value = kzalloc(size, GFP_NOFS);
59 if (!value)
60 return ERR_PTR(-ENOMEM);
61 size = __btrfs_getxattr(inode, name, value, size);
62 if (size > 0) {
63 acl = posix_acl_from_xattr(value, size);
64 if (IS_ERR(acl)) {
65 kfree(value);
66 return acl;
67 }
68 set_cached_acl(inode, type, acl);
69 }
70 kfree(value);
71 } else if (size == -ENOENT || size == -ENODATA || size == 0) {
72 /* FIXME, who returns -ENOENT? I think nobody */
73 acl = NULL;
74 set_cached_acl(inode, type, acl);
75 } else {
76 acl = ERR_PTR(-EIO);
77 }
78
79 return acl;
80}
81
82static int btrfs_xattr_acl_get(struct dentry *dentry, const char *name,
83 void *value, size_t size, int type)
84{
85 struct posix_acl *acl;
86 int ret = 0;
87
88 if (!IS_POSIXACL(dentry->d_inode))
89 return -EOPNOTSUPP;
90
91 acl = btrfs_get_acl(dentry->d_inode, type);
92
93 if (IS_ERR(acl))
94 return PTR_ERR(acl);
95 if (acl == NULL)
96 return -ENODATA;
97 ret = posix_acl_to_xattr(acl, value, size);
98 posix_acl_release(acl);
99
100 return ret;
101}
102
103/*
104 * Needs to be called with fs_mutex held
105 */
106static int btrfs_set_acl(struct btrfs_trans_handle *trans,
107 struct inode *inode, struct posix_acl *acl, int type)
108{
109 int ret, size = 0;
110 const char *name;
111 char *value = NULL;
112
113 if (acl) {
114 ret = posix_acl_valid(acl);
115 if (ret < 0)
116 return ret;
117 ret = 0;
118 }
119
120 switch (type) {
121 case ACL_TYPE_ACCESS:
122 name = POSIX_ACL_XATTR_ACCESS;
123 if (acl) {
124 ret = posix_acl_equiv_mode(acl, &inode->i_mode);
125 if (ret < 0)
126 return ret;
127 }
128 ret = 0;
129 break;
130 case ACL_TYPE_DEFAULT:
131 if (!S_ISDIR(inode->i_mode))
132 return acl ? -EINVAL : 0;
133 name = POSIX_ACL_XATTR_DEFAULT;
134 break;
135 default:
136 return -EINVAL;
137 }
138
139 if (acl) {
140 size = posix_acl_xattr_size(acl->a_count);
141 value = kmalloc(size, GFP_NOFS);
142 if (!value) {
143 ret = -ENOMEM;
144 goto out;
145 }
146
147 ret = posix_acl_to_xattr(acl, value, size);
148 if (ret < 0)
149 goto out;
150 }
151
152 ret = __btrfs_setxattr(trans, inode, name, value, size, 0);
153out:
154 kfree(value);
155
156 if (!ret)
157 set_cached_acl(inode, type, acl);
158
159 return ret;
160}
161
162static int btrfs_xattr_acl_set(struct dentry *dentry, const char *name,
163 const void *value, size_t size, int flags, int type)
164{
165 int ret;
166 struct posix_acl *acl = NULL;
167
168 if (!inode_owner_or_capable(dentry->d_inode))
169 return -EPERM;
170
171 if (!IS_POSIXACL(dentry->d_inode))
172 return -EOPNOTSUPP;
173
174 if (value) {
175 acl = posix_acl_from_xattr(value, size);
176 if (IS_ERR(acl))
177 return PTR_ERR(acl);
178
179 if (acl) {
180 ret = posix_acl_valid(acl);
181 if (ret)
182 goto out;
183 }
184 }
185
186 ret = btrfs_set_acl(NULL, dentry->d_inode, acl, type);
187out:
188 posix_acl_release(acl);
189
190 return ret;
191}
192
193/*
194 * btrfs_init_acl is already generally called under fs_mutex, so the locking
195 * stuff has been fixed to work with that. If the locking stuff changes, we
196 * need to re-evaluate the acl locking stuff.
197 */
198int btrfs_init_acl(struct btrfs_trans_handle *trans,
199 struct inode *inode, struct inode *dir)
200{
201 struct posix_acl *acl = NULL;
202 int ret = 0;
203
204 /* this happens with subvols */
205 if (!dir)
206 return 0;
207
208 if (!S_ISLNK(inode->i_mode)) {
209 if (IS_POSIXACL(dir)) {
210 acl = btrfs_get_acl(dir, ACL_TYPE_DEFAULT);
211 if (IS_ERR(acl))
212 return PTR_ERR(acl);
213 }
214
215 if (!acl)
216 inode->i_mode &= ~current_umask();
217 }
218
219 if (IS_POSIXACL(dir) && acl) {
220 if (S_ISDIR(inode->i_mode)) {
221 ret = btrfs_set_acl(trans, inode, acl,
222 ACL_TYPE_DEFAULT);
223 if (ret)
224 goto failed;
225 }
226 ret = posix_acl_create(&acl, GFP_NOFS, &inode->i_mode);
227 if (ret < 0)
228 return ret;
229
230 if (ret > 0) {
231 /* we need an acl */
232 ret = btrfs_set_acl(trans, inode, acl, ACL_TYPE_ACCESS);
233 }
234 }
235failed:
236 posix_acl_release(acl);
237
238 return ret;
239}
240
241int btrfs_acl_chmod(struct inode *inode)
242{
243 struct posix_acl *acl;
244 int ret = 0;
245
246 if (S_ISLNK(inode->i_mode))
247 return -EOPNOTSUPP;
248
249 if (!IS_POSIXACL(inode))
250 return 0;
251
252 acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS);
253 if (IS_ERR_OR_NULL(acl))
254 return PTR_ERR(acl);
255
256 ret = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
257 if (ret)
258 return ret;
259 ret = btrfs_set_acl(NULL, inode, acl, ACL_TYPE_ACCESS);
260 posix_acl_release(acl);
261 return ret;
262}
263
264const struct xattr_handler btrfs_xattr_acl_default_handler = {
265 .prefix = POSIX_ACL_XATTR_DEFAULT,
266 .flags = ACL_TYPE_DEFAULT,
267 .get = btrfs_xattr_acl_get,
268 .set = btrfs_xattr_acl_set,
269};
270
271const struct xattr_handler btrfs_xattr_acl_access_handler = {
272 .prefix = POSIX_ACL_XATTR_ACCESS,
273 .flags = ACL_TYPE_ACCESS,
274 .get = btrfs_xattr_acl_get,
275 .set = btrfs_xattr_acl_set,
276};