Commit | Line | Data |
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ef14f0c1 CH |
1 | /* |
2 | * Copyright (c) 2008, Christoph Hellwig | |
3 | * All Rights Reserved. | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or | |
6 | * modify it under the terms of the GNU General Public License as | |
7 | * published by the Free Software Foundation. | |
8 | * | |
9 | * This program is distributed in the hope that it would be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License | |
15 | * along with this program; if not, write the Free Software Foundation, | |
16 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA | |
17 | */ | |
18 | #include "xfs.h" | |
19 | #include "xfs_acl.h" | |
20 | #include "xfs_attr.h" | |
21 | #include "xfs_bmap_btree.h" | |
22 | #include "xfs_inode.h" | |
23 | #include "xfs_vnodeops.h" | |
0b1b213f | 24 | #include "xfs_trace.h" |
ef14f0c1 CH |
25 | #include <linux/xattr.h> |
26 | #include <linux/posix_acl_xattr.h> | |
27 | ||
28 | ||
ef14f0c1 CH |
29 | /* |
30 | * Locking scheme: | |
31 | * - all ACL updates are protected by inode->i_mutex, which is taken before | |
32 | * calling into this file. | |
ef14f0c1 CH |
33 | */ |
34 | ||
35 | STATIC struct posix_acl * | |
36 | xfs_acl_from_disk(struct xfs_acl *aclp) | |
37 | { | |
38 | struct posix_acl_entry *acl_e; | |
39 | struct posix_acl *acl; | |
40 | struct xfs_acl_entry *ace; | |
41 | int count, i; | |
42 | ||
43 | count = be32_to_cpu(aclp->acl_cnt); | |
44 | ||
45 | acl = posix_acl_alloc(count, GFP_KERNEL); | |
46 | if (!acl) | |
47 | return ERR_PTR(-ENOMEM); | |
48 | ||
49 | for (i = 0; i < count; i++) { | |
50 | acl_e = &acl->a_entries[i]; | |
51 | ace = &aclp->acl_entry[i]; | |
52 | ||
53 | /* | |
54 | * The tag is 32 bits on disk and 16 bits in core. | |
55 | * | |
56 | * Because every access to it goes through the core | |
57 | * format first this is not a problem. | |
58 | */ | |
59 | acl_e->e_tag = be32_to_cpu(ace->ae_tag); | |
60 | acl_e->e_perm = be16_to_cpu(ace->ae_perm); | |
61 | ||
62 | switch (acl_e->e_tag) { | |
63 | case ACL_USER: | |
64 | case ACL_GROUP: | |
65 | acl_e->e_id = be32_to_cpu(ace->ae_id); | |
66 | break; | |
67 | case ACL_USER_OBJ: | |
68 | case ACL_GROUP_OBJ: | |
69 | case ACL_MASK: | |
70 | case ACL_OTHER: | |
71 | acl_e->e_id = ACL_UNDEFINED_ID; | |
72 | break; | |
73 | default: | |
74 | goto fail; | |
75 | } | |
76 | } | |
77 | return acl; | |
78 | ||
79 | fail: | |
80 | posix_acl_release(acl); | |
81 | return ERR_PTR(-EINVAL); | |
82 | } | |
83 | ||
84 | STATIC void | |
85 | xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl) | |
86 | { | |
87 | const struct posix_acl_entry *acl_e; | |
88 | struct xfs_acl_entry *ace; | |
89 | int i; | |
90 | ||
91 | aclp->acl_cnt = cpu_to_be32(acl->a_count); | |
92 | for (i = 0; i < acl->a_count; i++) { | |
93 | ace = &aclp->acl_entry[i]; | |
94 | acl_e = &acl->a_entries[i]; | |
95 | ||
96 | ace->ae_tag = cpu_to_be32(acl_e->e_tag); | |
97 | ace->ae_id = cpu_to_be32(acl_e->e_id); | |
98 | ace->ae_perm = cpu_to_be16(acl_e->e_perm); | |
99 | } | |
100 | } | |
101 | ||
ef14f0c1 CH |
102 | struct posix_acl * |
103 | xfs_get_acl(struct inode *inode, int type) | |
104 | { | |
105 | struct xfs_inode *ip = XFS_I(inode); | |
1cbd20d8 | 106 | struct posix_acl *acl; |
ef14f0c1 CH |
107 | struct xfs_acl *xfs_acl; |
108 | int len = sizeof(struct xfs_acl); | |
109 | char *ea_name; | |
110 | int error; | |
111 | ||
1cbd20d8 AV |
112 | acl = get_cached_acl(inode, type); |
113 | if (acl != ACL_NOT_CACHED) | |
114 | return acl; | |
115 | ||
ef14f0c1 CH |
116 | switch (type) { |
117 | case ACL_TYPE_ACCESS: | |
118 | ea_name = SGI_ACL_FILE; | |
ef14f0c1 CH |
119 | break; |
120 | case ACL_TYPE_DEFAULT: | |
121 | ea_name = SGI_ACL_DEFAULT; | |
ef14f0c1 CH |
122 | break; |
123 | default: | |
1cbd20d8 | 124 | BUG(); |
ef14f0c1 CH |
125 | } |
126 | ||
ef14f0c1 CH |
127 | /* |
128 | * If we have a cached ACLs value just return it, not need to | |
129 | * go out to the disk. | |
130 | */ | |
ef14f0c1 CH |
131 | |
132 | xfs_acl = kzalloc(sizeof(struct xfs_acl), GFP_KERNEL); | |
133 | if (!xfs_acl) | |
134 | return ERR_PTR(-ENOMEM); | |
135 | ||
136 | error = -xfs_attr_get(ip, ea_name, (char *)xfs_acl, &len, ATTR_ROOT); | |
137 | if (error) { | |
138 | /* | |
139 | * If the attribute doesn't exist make sure we have a negative | |
140 | * cache entry, for any other error assume it is transient and | |
1cbd20d8 | 141 | * leave the cache entry as ACL_NOT_CACHED. |
ef14f0c1 CH |
142 | */ |
143 | if (error == -ENOATTR) { | |
144 | acl = NULL; | |
145 | goto out_update_cache; | |
146 | } | |
147 | goto out; | |
148 | } | |
149 | ||
150 | acl = xfs_acl_from_disk(xfs_acl); | |
151 | if (IS_ERR(acl)) | |
152 | goto out; | |
153 | ||
154 | out_update_cache: | |
1cbd20d8 | 155 | set_cached_acl(inode, type, acl); |
ef14f0c1 CH |
156 | out: |
157 | kfree(xfs_acl); | |
158 | return acl; | |
159 | } | |
160 | ||
161 | STATIC int | |
162 | xfs_set_acl(struct inode *inode, int type, struct posix_acl *acl) | |
163 | { | |
164 | struct xfs_inode *ip = XFS_I(inode); | |
ef14f0c1 CH |
165 | char *ea_name; |
166 | int error; | |
167 | ||
168 | if (S_ISLNK(inode->i_mode)) | |
169 | return -EOPNOTSUPP; | |
170 | ||
171 | switch (type) { | |
172 | case ACL_TYPE_ACCESS: | |
173 | ea_name = SGI_ACL_FILE; | |
ef14f0c1 CH |
174 | break; |
175 | case ACL_TYPE_DEFAULT: | |
176 | if (!S_ISDIR(inode->i_mode)) | |
177 | return acl ? -EACCES : 0; | |
178 | ea_name = SGI_ACL_DEFAULT; | |
ef14f0c1 CH |
179 | break; |
180 | default: | |
181 | return -EINVAL; | |
182 | } | |
183 | ||
184 | if (acl) { | |
185 | struct xfs_acl *xfs_acl; | |
186 | int len; | |
187 | ||
188 | xfs_acl = kzalloc(sizeof(struct xfs_acl), GFP_KERNEL); | |
189 | if (!xfs_acl) | |
190 | return -ENOMEM; | |
191 | ||
192 | xfs_acl_to_disk(xfs_acl, acl); | |
193 | len = sizeof(struct xfs_acl) - | |
194 | (sizeof(struct xfs_acl_entry) * | |
195 | (XFS_ACL_MAX_ENTRIES - acl->a_count)); | |
196 | ||
197 | error = -xfs_attr_set(ip, ea_name, (char *)xfs_acl, | |
198 | len, ATTR_ROOT); | |
199 | ||
200 | kfree(xfs_acl); | |
201 | } else { | |
202 | /* | |
203 | * A NULL ACL argument means we want to remove the ACL. | |
204 | */ | |
205 | error = -xfs_attr_remove(ip, ea_name, ATTR_ROOT); | |
206 | ||
207 | /* | |
208 | * If the attribute didn't exist to start with that's fine. | |
209 | */ | |
210 | if (error == -ENOATTR) | |
211 | error = 0; | |
212 | } | |
213 | ||
214 | if (!error) | |
1cbd20d8 | 215 | set_cached_acl(inode, type, acl); |
ef14f0c1 CH |
216 | return error; |
217 | } | |
218 | ||
219 | int | |
220 | xfs_check_acl(struct inode *inode, int mask) | |
221 | { | |
222 | struct xfs_inode *ip = XFS_I(inode); | |
223 | struct posix_acl *acl; | |
224 | int error = -EAGAIN; | |
225 | ||
226 | xfs_itrace_entry(ip); | |
227 | ||
228 | /* | |
229 | * If there is no attribute fork no ACL exists on this inode and | |
230 | * we can skip the whole exercise. | |
231 | */ | |
232 | if (!XFS_IFORK_Q(ip)) | |
233 | return -EAGAIN; | |
234 | ||
235 | acl = xfs_get_acl(inode, ACL_TYPE_ACCESS); | |
236 | if (IS_ERR(acl)) | |
237 | return PTR_ERR(acl); | |
238 | if (acl) { | |
239 | error = posix_acl_permission(inode, acl, mask); | |
240 | posix_acl_release(acl); | |
241 | } | |
242 | ||
243 | return error; | |
244 | } | |
245 | ||
246 | static int | |
247 | xfs_set_mode(struct inode *inode, mode_t mode) | |
248 | { | |
249 | int error = 0; | |
250 | ||
251 | if (mode != inode->i_mode) { | |
252 | struct iattr iattr; | |
253 | ||
d6d59bad | 254 | iattr.ia_valid = ATTR_MODE | ATTR_CTIME; |
ef14f0c1 | 255 | iattr.ia_mode = mode; |
d6d59bad | 256 | iattr.ia_ctime = current_fs_time(inode->i_sb); |
ef14f0c1 CH |
257 | |
258 | error = -xfs_setattr(XFS_I(inode), &iattr, XFS_ATTR_NOACL); | |
259 | } | |
260 | ||
261 | return error; | |
262 | } | |
263 | ||
264 | static int | |
265 | xfs_acl_exists(struct inode *inode, char *name) | |
266 | { | |
267 | int len = sizeof(struct xfs_acl); | |
268 | ||
269 | return (xfs_attr_get(XFS_I(inode), name, NULL, &len, | |
270 | ATTR_ROOT|ATTR_KERNOVAL) == 0); | |
271 | } | |
272 | ||
273 | int | |
274 | posix_acl_access_exists(struct inode *inode) | |
275 | { | |
276 | return xfs_acl_exists(inode, SGI_ACL_FILE); | |
277 | } | |
278 | ||
279 | int | |
280 | posix_acl_default_exists(struct inode *inode) | |
281 | { | |
282 | if (!S_ISDIR(inode->i_mode)) | |
283 | return 0; | |
284 | return xfs_acl_exists(inode, SGI_ACL_DEFAULT); | |
285 | } | |
286 | ||
287 | /* | |
288 | * No need for i_mutex because the inode is not yet exposed to the VFS. | |
289 | */ | |
290 | int | |
291 | xfs_inherit_acl(struct inode *inode, struct posix_acl *default_acl) | |
292 | { | |
293 | struct posix_acl *clone; | |
294 | mode_t mode; | |
295 | int error = 0, inherit = 0; | |
296 | ||
297 | if (S_ISDIR(inode->i_mode)) { | |
298 | error = xfs_set_acl(inode, ACL_TYPE_DEFAULT, default_acl); | |
299 | if (error) | |
300 | return error; | |
301 | } | |
302 | ||
303 | clone = posix_acl_clone(default_acl, GFP_KERNEL); | |
304 | if (!clone) | |
305 | return -ENOMEM; | |
306 | ||
307 | mode = inode->i_mode; | |
308 | error = posix_acl_create_masq(clone, &mode); | |
309 | if (error < 0) | |
310 | goto out_release_clone; | |
311 | ||
312 | /* | |
313 | * If posix_acl_create_masq returns a positive value we need to | |
314 | * inherit a permission that can't be represented using the Unix | |
315 | * mode bits and we actually need to set an ACL. | |
316 | */ | |
317 | if (error > 0) | |
318 | inherit = 1; | |
319 | ||
320 | error = xfs_set_mode(inode, mode); | |
321 | if (error) | |
322 | goto out_release_clone; | |
323 | ||
324 | if (inherit) | |
325 | error = xfs_set_acl(inode, ACL_TYPE_ACCESS, clone); | |
326 | ||
327 | out_release_clone: | |
328 | posix_acl_release(clone); | |
329 | return error; | |
330 | } | |
331 | ||
332 | int | |
333 | xfs_acl_chmod(struct inode *inode) | |
334 | { | |
335 | struct posix_acl *acl, *clone; | |
336 | int error; | |
337 | ||
338 | if (S_ISLNK(inode->i_mode)) | |
339 | return -EOPNOTSUPP; | |
340 | ||
341 | acl = xfs_get_acl(inode, ACL_TYPE_ACCESS); | |
342 | if (IS_ERR(acl) || !acl) | |
343 | return PTR_ERR(acl); | |
344 | ||
345 | clone = posix_acl_clone(acl, GFP_KERNEL); | |
346 | posix_acl_release(acl); | |
347 | if (!clone) | |
348 | return -ENOMEM; | |
349 | ||
350 | error = posix_acl_chmod_masq(clone, inode->i_mode); | |
351 | if (!error) | |
352 | error = xfs_set_acl(inode, ACL_TYPE_ACCESS, clone); | |
353 | ||
354 | posix_acl_release(clone); | |
355 | return error; | |
356 | } | |
357 | ||
ef14f0c1 | 358 | static int |
431547b3 CH |
359 | xfs_xattr_acl_get(struct dentry *dentry, const char *name, |
360 | void *value, size_t size, int type) | |
ef14f0c1 CH |
361 | { |
362 | struct posix_acl *acl; | |
431547b3 | 363 | int error; |
ef14f0c1 | 364 | |
431547b3 | 365 | acl = xfs_get_acl(dentry->d_inode, type); |
ef14f0c1 CH |
366 | if (IS_ERR(acl)) |
367 | return PTR_ERR(acl); | |
368 | if (acl == NULL) | |
369 | return -ENODATA; | |
370 | ||
371 | error = posix_acl_to_xattr(acl, value, size); | |
372 | posix_acl_release(acl); | |
373 | ||
374 | return error; | |
375 | } | |
376 | ||
377 | static int | |
431547b3 CH |
378 | xfs_xattr_acl_set(struct dentry *dentry, const char *name, |
379 | const void *value, size_t size, int flags, int type) | |
ef14f0c1 | 380 | { |
431547b3 | 381 | struct inode *inode = dentry->d_inode; |
ef14f0c1 | 382 | struct posix_acl *acl = NULL; |
431547b3 | 383 | int error = 0; |
ef14f0c1 | 384 | |
ef14f0c1 CH |
385 | if (flags & XATTR_CREATE) |
386 | return -EINVAL; | |
387 | if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode)) | |
388 | return value ? -EACCES : 0; | |
389 | if ((current_fsuid() != inode->i_uid) && !capable(CAP_FOWNER)) | |
390 | return -EPERM; | |
391 | ||
392 | if (!value) | |
393 | goto set_acl; | |
394 | ||
395 | acl = posix_acl_from_xattr(value, size); | |
396 | if (!acl) { | |
397 | /* | |
398 | * acl_set_file(3) may request that we set default ACLs with | |
399 | * zero length -- defend (gracefully) against that here. | |
400 | */ | |
401 | goto out; | |
402 | } | |
403 | if (IS_ERR(acl)) { | |
404 | error = PTR_ERR(acl); | |
405 | goto out; | |
406 | } | |
407 | ||
408 | error = posix_acl_valid(acl); | |
409 | if (error) | |
410 | goto out_release; | |
411 | ||
412 | error = -EINVAL; | |
413 | if (acl->a_count > XFS_ACL_MAX_ENTRIES) | |
414 | goto out_release; | |
415 | ||
416 | if (type == ACL_TYPE_ACCESS) { | |
417 | mode_t mode = inode->i_mode; | |
418 | error = posix_acl_equiv_mode(acl, &mode); | |
419 | ||
420 | if (error <= 0) { | |
421 | posix_acl_release(acl); | |
422 | acl = NULL; | |
423 | ||
424 | if (error < 0) | |
425 | return error; | |
426 | } | |
427 | ||
428 | error = xfs_set_mode(inode, mode); | |
429 | if (error) | |
430 | goto out_release; | |
431 | } | |
432 | ||
433 | set_acl: | |
434 | error = xfs_set_acl(inode, type, acl); | |
435 | out_release: | |
436 | posix_acl_release(acl); | |
437 | out: | |
438 | return error; | |
439 | } | |
440 | ||
431547b3 CH |
441 | struct xattr_handler xfs_xattr_acl_access_handler = { |
442 | .prefix = POSIX_ACL_XATTR_ACCESS, | |
443 | .flags = ACL_TYPE_ACCESS, | |
444 | .get = xfs_xattr_acl_get, | |
445 | .set = xfs_xattr_acl_set, | |
446 | }; | |
447 | ||
448 | struct xattr_handler xfs_xattr_acl_default_handler = { | |
449 | .prefix = POSIX_ACL_XATTR_DEFAULT, | |
450 | .flags = ACL_TYPE_DEFAULT, | |
451 | .get = xfs_xattr_acl_get, | |
452 | .set = xfs_xattr_acl_set, | |
ef14f0c1 | 453 | }; |