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
31 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
32
btrfs_get_acl(struct inode * inode,int type)33 static struct posix_acl *btrfs_get_acl(struct inode *inode, int type)
34 {
35 int size;
36 const char *name;
37 char *value = NULL;
38 struct posix_acl *acl;
39
40 if (!IS_POSIXACL(inode))
41 return NULL;
42
43 acl = get_cached_acl(inode, type);
44 if (acl != ACL_NOT_CACHED)
45 return acl;
46
47 switch (type) {
48 case ACL_TYPE_ACCESS:
49 name = POSIX_ACL_XATTR_ACCESS;
50 break;
51 case ACL_TYPE_DEFAULT:
52 name = POSIX_ACL_XATTR_DEFAULT;
53 break;
54 default:
55 BUG();
56 }
57
58 size = __btrfs_getxattr(inode, name, "", 0);
59 if (size > 0) {
60 value = kzalloc(size, GFP_NOFS);
61 if (!value)
62 return ERR_PTR(-ENOMEM);
63 size = __btrfs_getxattr(inode, name, value, size);
64 if (size > 0) {
65 acl = posix_acl_from_xattr(value, size);
66 if (IS_ERR(acl)) {
67 kfree(value);
68 return acl;
69 }
70 set_cached_acl(inode, type, acl);
71 }
72 kfree(value);
73 } else if (size == -ENOENT || size == -ENODATA || size == 0) {
74 /* FIXME, who returns -ENOENT? I think nobody */
75 acl = NULL;
76 set_cached_acl(inode, type, acl);
77 } else {
78 acl = ERR_PTR(-EIO);
79 }
80
81 return acl;
82 }
83
btrfs_xattr_acl_get(struct dentry * dentry,const char * name,void * value,size_t size,int type)84 static int btrfs_xattr_acl_get(struct dentry *dentry, const char *name,
85 void *value, size_t size, int type)
86 {
87 struct posix_acl *acl;
88 int ret = 0;
89
90 if (!IS_POSIXACL(dentry->d_inode))
91 return -EOPNOTSUPP;
92
93 acl = btrfs_get_acl(dentry->d_inode, type);
94
95 if (IS_ERR(acl))
96 return PTR_ERR(acl);
97 if (acl == NULL)
98 return -ENODATA;
99 ret = posix_acl_to_xattr(acl, value, size);
100 posix_acl_release(acl);
101
102 return ret;
103 }
104
105 /*
106 * Needs to be called with fs_mutex held
107 */
btrfs_set_acl(struct btrfs_trans_handle * trans,struct inode * inode,struct posix_acl * acl,int type)108 static int btrfs_set_acl(struct btrfs_trans_handle *trans,
109 struct inode *inode, struct posix_acl *acl, int type)
110 {
111 int ret, size = 0;
112 const char *name;
113 char *value = NULL;
114 mode_t mode;
115
116 if (acl) {
117 ret = posix_acl_valid(acl);
118 if (ret < 0)
119 return ret;
120 ret = 0;
121 }
122
123 switch (type) {
124 case ACL_TYPE_ACCESS:
125 mode = inode->i_mode;
126 name = POSIX_ACL_XATTR_ACCESS;
127 if (acl) {
128 ret = posix_acl_equiv_mode(acl, &mode);
129 if (ret < 0)
130 return ret;
131 inode->i_mode = mode;
132 }
133 ret = 0;
134 break;
135 case ACL_TYPE_DEFAULT:
136 if (!S_ISDIR(inode->i_mode))
137 return acl ? -EINVAL : 0;
138 name = POSIX_ACL_XATTR_DEFAULT;
139 break;
140 default:
141 return -EINVAL;
142 }
143
144 if (acl) {
145 size = posix_acl_xattr_size(acl->a_count);
146 value = kmalloc(size, GFP_NOFS);
147 if (!value) {
148 ret = -ENOMEM;
149 goto out;
150 }
151
152 ret = posix_acl_to_xattr(acl, value, size);
153 if (ret < 0)
154 goto out;
155 }
156
157 ret = __btrfs_setxattr(trans, inode, name, value, size, 0);
158 out:
159 kfree(value);
160
161 if (!ret)
162 set_cached_acl(inode, type, acl);
163
164 return ret;
165 }
166
btrfs_xattr_acl_set(struct dentry * dentry,const char * name,const void * value,size_t size,int flags,int type)167 static int btrfs_xattr_acl_set(struct dentry *dentry, const char *name,
168 const void *value, size_t size, int flags, int type)
169 {
170 int ret;
171 struct posix_acl *acl = NULL;
172
173 if (!inode_owner_or_capable(dentry->d_inode))
174 return -EPERM;
175
176 if (!IS_POSIXACL(dentry->d_inode))
177 return -EOPNOTSUPP;
178
179 if (value) {
180 acl = posix_acl_from_xattr(value, size);
181 if (IS_ERR(acl))
182 return PTR_ERR(acl);
183
184 if (acl) {
185 ret = posix_acl_valid(acl);
186 if (ret)
187 goto out;
188 }
189 }
190
191 ret = btrfs_set_acl(NULL, dentry->d_inode, acl, type);
192 out:
193 posix_acl_release(acl);
194
195 return ret;
196 }
197
btrfs_check_acl(struct inode * inode,int mask,unsigned int flags)198 int btrfs_check_acl(struct inode *inode, int mask, unsigned int flags)
199 {
200 int error = -EAGAIN;
201
202 if (flags & IPERM_FLAG_RCU) {
203 if (!negative_cached_acl(inode, ACL_TYPE_ACCESS))
204 error = -ECHILD;
205
206 } else {
207 struct posix_acl *acl;
208 acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS);
209 if (IS_ERR(acl))
210 return PTR_ERR(acl);
211 if (acl) {
212 error = posix_acl_permission(inode, acl, mask);
213 posix_acl_release(acl);
214 }
215 }
216
217 return error;
218 }
219
220 /*
221 * btrfs_init_acl is already generally called under fs_mutex, so the locking
222 * stuff has been fixed to work with that. If the locking stuff changes, we
223 * need to re-evaluate the acl locking stuff.
224 */
btrfs_init_acl(struct btrfs_trans_handle * trans,struct inode * inode,struct inode * dir)225 int btrfs_init_acl(struct btrfs_trans_handle *trans,
226 struct inode *inode, struct inode *dir)
227 {
228 struct posix_acl *acl = NULL;
229 int ret = 0;
230
231 /* this happens with subvols */
232 if (!dir)
233 return 0;
234
235 if (!S_ISLNK(inode->i_mode)) {
236 if (IS_POSIXACL(dir)) {
237 acl = btrfs_get_acl(dir, ACL_TYPE_DEFAULT);
238 if (IS_ERR(acl))
239 return PTR_ERR(acl);
240 }
241
242 if (!acl)
243 inode->i_mode &= ~current_umask();
244 }
245
246 if (IS_POSIXACL(dir) && acl) {
247 struct posix_acl *clone;
248 mode_t mode;
249
250 if (S_ISDIR(inode->i_mode)) {
251 ret = btrfs_set_acl(trans, inode, acl,
252 ACL_TYPE_DEFAULT);
253 if (ret)
254 goto failed;
255 }
256 clone = posix_acl_clone(acl, GFP_NOFS);
257 ret = -ENOMEM;
258 if (!clone)
259 goto failed;
260
261 mode = inode->i_mode;
262 ret = posix_acl_create_masq(clone, &mode);
263 if (ret >= 0) {
264 inode->i_mode = mode;
265 if (ret > 0) {
266 /* we need an acl */
267 ret = btrfs_set_acl(trans, inode, clone,
268 ACL_TYPE_ACCESS);
269 }
270 }
271 posix_acl_release(clone);
272 }
273 failed:
274 posix_acl_release(acl);
275
276 return ret;
277 }
278
btrfs_acl_chmod(struct inode * inode)279 int btrfs_acl_chmod(struct inode *inode)
280 {
281 struct posix_acl *acl, *clone;
282 int ret = 0;
283
284 if (S_ISLNK(inode->i_mode))
285 return -EOPNOTSUPP;
286
287 if (!IS_POSIXACL(inode))
288 return 0;
289
290 acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS);
291 if (IS_ERR(acl) || !acl)
292 return PTR_ERR(acl);
293
294 clone = posix_acl_clone(acl, GFP_KERNEL);
295 posix_acl_release(acl);
296 if (!clone)
297 return -ENOMEM;
298
299 ret = posix_acl_chmod_masq(clone, inode->i_mode);
300 if (!ret)
301 ret = btrfs_set_acl(NULL, inode, clone, ACL_TYPE_ACCESS);
302
303 posix_acl_release(clone);
304
305 return ret;
306 }
307
308 const struct xattr_handler btrfs_xattr_acl_default_handler = {
309 .prefix = POSIX_ACL_XATTR_DEFAULT,
310 .flags = ACL_TYPE_DEFAULT,
311 .get = btrfs_xattr_acl_get,
312 .set = btrfs_xattr_acl_set,
313 };
314
315 const struct xattr_handler btrfs_xattr_acl_access_handler = {
316 .prefix = POSIX_ACL_XATTR_ACCESS,
317 .flags = ACL_TYPE_ACCESS,
318 .get = btrfs_xattr_acl_get,
319 .set = btrfs_xattr_acl_set,
320 };
321
322 #else /* CONFIG_BTRFS_FS_POSIX_ACL */
323
btrfs_acl_chmod(struct inode * inode)324 int btrfs_acl_chmod(struct inode *inode)
325 {
326 return 0;
327 }
328
btrfs_init_acl(struct btrfs_trans_handle * trans,struct inode * inode,struct inode * dir)329 int btrfs_init_acl(struct btrfs_trans_handle *trans,
330 struct inode *inode, struct inode *dir)
331 {
332 return 0;
333 }
334
335 #endif /* CONFIG_BTRFS_FS_POSIX_ACL */
336