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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 | ||
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 | ||
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 | */ | |
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 | ||
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 (acl) { | |
182 | ret = posix_acl_valid(acl); | |
183 | if (ret) | |
184 | goto out; | |
185 | } else if (IS_ERR(acl)) { | |
186 | return PTR_ERR(acl); | |
187 | } | |
188 | } | |
189 | ||
190 | ret = btrfs_set_acl(NULL, dentry->d_inode, acl, type); | |
191 | out: | |
192 | posix_acl_release(acl); | |
193 | ||
194 | return ret; | |
195 | } | |
196 | ||
197 | int btrfs_check_acl(struct inode *inode, int mask, unsigned int flags) | |
198 | { | |
199 | int error = -EAGAIN; | |
200 | ||
201 | if (flags & IPERM_FLAG_RCU) { | |
202 | if (!negative_cached_acl(inode, ACL_TYPE_ACCESS)) | |
203 | error = -ECHILD; | |
204 | ||
205 | } else { | |
206 | struct posix_acl *acl; | |
207 | acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS); | |
208 | if (IS_ERR(acl)) | |
209 | return PTR_ERR(acl); | |
210 | if (acl) { | |
211 | error = posix_acl_permission(inode, acl, mask); | |
212 | posix_acl_release(acl); | |
213 | } | |
214 | } | |
215 | ||
216 | return error; | |
217 | } | |
218 | ||
219 | /* | |
220 | * btrfs_init_acl is already generally called under fs_mutex, so the locking | |
221 | * stuff has been fixed to work with that. If the locking stuff changes, we | |
222 | * need to re-evaluate the acl locking stuff. | |
223 | */ | |
224 | int btrfs_init_acl(struct btrfs_trans_handle *trans, | |
225 | struct inode *inode, struct inode *dir) | |
226 | { | |
227 | struct posix_acl *acl = NULL; | |
228 | int ret = 0; | |
229 | ||
230 | /* this happens with subvols */ | |
231 | if (!dir) | |
232 | return 0; | |
233 | ||
234 | if (!S_ISLNK(inode->i_mode)) { | |
235 | if (IS_POSIXACL(dir)) { | |
236 | acl = btrfs_get_acl(dir, ACL_TYPE_DEFAULT); | |
237 | if (IS_ERR(acl)) | |
238 | return PTR_ERR(acl); | |
239 | } | |
240 | ||
241 | if (!acl) | |
242 | inode->i_mode &= ~current_umask(); | |
243 | } | |
244 | ||
245 | if (IS_POSIXACL(dir) && acl) { | |
246 | struct posix_acl *clone; | |
247 | mode_t mode; | |
248 | ||
249 | if (S_ISDIR(inode->i_mode)) { | |
250 | ret = btrfs_set_acl(trans, inode, acl, | |
251 | ACL_TYPE_DEFAULT); | |
252 | if (ret) | |
253 | goto failed; | |
254 | } | |
255 | clone = posix_acl_clone(acl, GFP_NOFS); | |
256 | ret = -ENOMEM; | |
257 | if (!clone) | |
258 | goto failed; | |
259 | ||
260 | mode = inode->i_mode; | |
261 | ret = posix_acl_create_masq(clone, &mode); | |
262 | if (ret >= 0) { | |
263 | inode->i_mode = mode; | |
264 | if (ret > 0) { | |
265 | /* we need an acl */ | |
266 | ret = btrfs_set_acl(trans, inode, clone, | |
267 | ACL_TYPE_ACCESS); | |
268 | } | |
269 | } | |
270 | posix_acl_release(clone); | |
271 | } | |
272 | failed: | |
273 | posix_acl_release(acl); | |
274 | ||
275 | return ret; | |
276 | } | |
277 | ||
278 | int btrfs_acl_chmod(struct inode *inode) | |
279 | { | |
280 | struct posix_acl *acl, *clone; | |
281 | int ret = 0; | |
282 | ||
283 | if (S_ISLNK(inode->i_mode)) | |
284 | return -EOPNOTSUPP; | |
285 | ||
286 | if (!IS_POSIXACL(inode)) | |
287 | return 0; | |
288 | ||
289 | acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS); | |
290 | if (IS_ERR_OR_NULL(acl)) | |
291 | return PTR_ERR(acl); | |
292 | ||
293 | clone = posix_acl_clone(acl, GFP_KERNEL); | |
294 | posix_acl_release(acl); | |
295 | if (!clone) | |
296 | return -ENOMEM; | |
297 | ||
298 | ret = posix_acl_chmod_masq(clone, inode->i_mode); | |
299 | if (!ret) | |
300 | ret = btrfs_set_acl(NULL, inode, clone, ACL_TYPE_ACCESS); | |
301 | ||
302 | posix_acl_release(clone); | |
303 | ||
304 | return ret; | |
305 | } | |
306 | ||
307 | const struct xattr_handler btrfs_xattr_acl_default_handler = { | |
308 | .prefix = POSIX_ACL_XATTR_DEFAULT, | |
309 | .flags = ACL_TYPE_DEFAULT, | |
310 | .get = btrfs_xattr_acl_get, | |
311 | .set = btrfs_xattr_acl_set, | |
312 | }; | |
313 | ||
314 | const struct xattr_handler btrfs_xattr_acl_access_handler = { | |
315 | .prefix = POSIX_ACL_XATTR_ACCESS, | |
316 | .flags = ACL_TYPE_ACCESS, | |
317 | .get = btrfs_xattr_acl_get, | |
318 | .set = btrfs_xattr_acl_set, | |
319 | }; | |
320 | ||
321 | #else /* CONFIG_BTRFS_FS_POSIX_ACL */ | |
322 | ||
323 | int btrfs_acl_chmod(struct inode *inode) | |
324 | { | |
325 | return 0; | |
326 | } | |
327 | ||
328 | int btrfs_init_acl(struct btrfs_trans_handle *trans, | |
329 | struct inode *inode, struct inode *dir) | |
330 | { | |
331 | return 0; | |
332 | } | |
333 | ||
334 | #endif /* CONFIG_BTRFS_FS_POSIX_ACL */ |