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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"
24#include "xfs_trace.h"
25#include <linux/slab.h>
26#include <linux/xattr.h>
27#include <linux/posix_acl_xattr.h>
28
29
30/*
31 * Locking scheme:
32 * - all ACL updates are protected by inode->i_mutex, which is taken before
33 * calling into this file.
34 */
35
36STATIC struct posix_acl *
37xfs_acl_from_disk(struct xfs_acl *aclp)
38{
39 struct posix_acl_entry *acl_e;
40 struct posix_acl *acl;
41 struct xfs_acl_entry *ace;
42 int count, i;
43
44 count = be32_to_cpu(aclp->acl_cnt);
45
46 acl = posix_acl_alloc(count, GFP_KERNEL);
47 if (!acl)
48 return ERR_PTR(-ENOMEM);
49
50 for (i = 0; i < count; i++) {
51 acl_e = &acl->a_entries[i];
52 ace = &aclp->acl_entry[i];
53
54 /*
55 * The tag is 32 bits on disk and 16 bits in core.
56 *
57 * Because every access to it goes through the core
58 * format first this is not a problem.
59 */
60 acl_e->e_tag = be32_to_cpu(ace->ae_tag);
61 acl_e->e_perm = be16_to_cpu(ace->ae_perm);
62
63 switch (acl_e->e_tag) {
64 case ACL_USER:
65 case ACL_GROUP:
66 acl_e->e_id = be32_to_cpu(ace->ae_id);
67 break;
68 case ACL_USER_OBJ:
69 case ACL_GROUP_OBJ:
70 case ACL_MASK:
71 case ACL_OTHER:
72 acl_e->e_id = ACL_UNDEFINED_ID;
73 break;
74 default:
75 goto fail;
76 }
77 }
78 return acl;
79
80fail:
81 posix_acl_release(acl);
82 return ERR_PTR(-EINVAL);
83}
84
85STATIC void
86xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl)
87{
88 const struct posix_acl_entry *acl_e;
89 struct xfs_acl_entry *ace;
90 int i;
91
92 aclp->acl_cnt = cpu_to_be32(acl->a_count);
93 for (i = 0; i < acl->a_count; i++) {
94 ace = &aclp->acl_entry[i];
95 acl_e = &acl->a_entries[i];
96
97 ace->ae_tag = cpu_to_be32(acl_e->e_tag);
98 ace->ae_id = cpu_to_be32(acl_e->e_id);
99 ace->ae_perm = cpu_to_be16(acl_e->e_perm);
100 }
101}
102
103struct posix_acl *
104xfs_get_acl(struct inode *inode, int type)
105{
106 struct xfs_inode *ip = XFS_I(inode);
107 struct posix_acl *acl;
108 struct xfs_acl *xfs_acl;
109 int len = sizeof(struct xfs_acl);
110 unsigned char *ea_name;
111 int error;
112
113 acl = get_cached_acl(inode, type);
114 if (acl != ACL_NOT_CACHED)
115 return acl;
116
117 trace_xfs_get_acl(ip);
118
119 switch (type) {
120 case ACL_TYPE_ACCESS:
121 ea_name = SGI_ACL_FILE;
122 break;
123 case ACL_TYPE_DEFAULT:
124 ea_name = SGI_ACL_DEFAULT;
125 break;
126 default:
127 BUG();
128 }
129
130 /*
131 * If we have a cached ACLs value just return it, not need to
132 * go out to the disk.
133 */
134
135 xfs_acl = kzalloc(sizeof(struct xfs_acl), GFP_KERNEL);
136 if (!xfs_acl)
137 return ERR_PTR(-ENOMEM);
138
139 error = -xfs_attr_get(ip, ea_name, (unsigned char *)xfs_acl,
140 &len, ATTR_ROOT);
141 if (error) {
142 /*
143 * If the attribute doesn't exist make sure we have a negative
144 * cache entry, for any other error assume it is transient and
145 * leave the cache entry as ACL_NOT_CACHED.
146 */
147 if (error == -ENOATTR) {
148 acl = NULL;
149 goto out_update_cache;
150 }
151 goto out;
152 }
153
154 acl = xfs_acl_from_disk(xfs_acl);
155 if (IS_ERR(acl))
156 goto out;
157
158 out_update_cache:
159 set_cached_acl(inode, type, acl);
160 out:
161 kfree(xfs_acl);
162 return acl;
163}
164
165STATIC int
166xfs_set_acl(struct inode *inode, int type, struct posix_acl *acl)
167{
168 struct xfs_inode *ip = XFS_I(inode);
169 unsigned char *ea_name;
170 int error;
171
172 if (S_ISLNK(inode->i_mode))
173 return -EOPNOTSUPP;
174
175 switch (type) {
176 case ACL_TYPE_ACCESS:
177 ea_name = SGI_ACL_FILE;
178 break;
179 case ACL_TYPE_DEFAULT:
180 if (!S_ISDIR(inode->i_mode))
181 return acl ? -EACCES : 0;
182 ea_name = SGI_ACL_DEFAULT;
183 break;
184 default:
185 return -EINVAL;
186 }
187
188 if (acl) {
189 struct xfs_acl *xfs_acl;
190 int len;
191
192 xfs_acl = kzalloc(sizeof(struct xfs_acl), GFP_KERNEL);
193 if (!xfs_acl)
194 return -ENOMEM;
195
196 xfs_acl_to_disk(xfs_acl, acl);
197 len = sizeof(struct xfs_acl) -
198 (sizeof(struct xfs_acl_entry) *
199 (XFS_ACL_MAX_ENTRIES - acl->a_count));
200
201 error = -xfs_attr_set(ip, ea_name, (unsigned char *)xfs_acl,
202 len, ATTR_ROOT);
203
204 kfree(xfs_acl);
205 } else {
206 /*
207 * A NULL ACL argument means we want to remove the ACL.
208 */
209 error = -xfs_attr_remove(ip, ea_name, ATTR_ROOT);
210
211 /*
212 * If the attribute didn't exist to start with that's fine.
213 */
214 if (error == -ENOATTR)
215 error = 0;
216 }
217
218 if (!error)
219 set_cached_acl(inode, type, acl);
220 return error;
221}
222
223static int
224xfs_set_mode(struct inode *inode, umode_t mode)
225{
226 int error = 0;
227
228 if (mode != inode->i_mode) {
229 struct iattr iattr;
230
231 iattr.ia_valid = ATTR_MODE | ATTR_CTIME;
232 iattr.ia_mode = mode;
233 iattr.ia_ctime = current_fs_time(inode->i_sb);
234
235 error = -xfs_setattr_nonsize(XFS_I(inode), &iattr, XFS_ATTR_NOACL);
236 }
237
238 return error;
239}
240
241static int
242xfs_acl_exists(struct inode *inode, unsigned char *name)
243{
244 int len = sizeof(struct xfs_acl);
245
246 return (xfs_attr_get(XFS_I(inode), name, NULL, &len,
247 ATTR_ROOT|ATTR_KERNOVAL) == 0);
248}
249
250int
251posix_acl_access_exists(struct inode *inode)
252{
253 return xfs_acl_exists(inode, SGI_ACL_FILE);
254}
255
256int
257posix_acl_default_exists(struct inode *inode)
258{
259 if (!S_ISDIR(inode->i_mode))
260 return 0;
261 return xfs_acl_exists(inode, SGI_ACL_DEFAULT);
262}
263
264/*
265 * No need for i_mutex because the inode is not yet exposed to the VFS.
266 */
267int
268xfs_inherit_acl(struct inode *inode, struct posix_acl *acl)
269{
270 umode_t mode = inode->i_mode;
271 int error = 0, inherit = 0;
272
273 if (S_ISDIR(inode->i_mode)) {
274 error = xfs_set_acl(inode, ACL_TYPE_DEFAULT, acl);
275 if (error)
276 goto out;
277 }
278
279 error = posix_acl_create(&acl, GFP_KERNEL, &mode);
280 if (error < 0)
281 return error;
282
283 /*
284 * If posix_acl_create returns a positive value we need to
285 * inherit a permission that can't be represented using the Unix
286 * mode bits and we actually need to set an ACL.
287 */
288 if (error > 0)
289 inherit = 1;
290
291 error = xfs_set_mode(inode, mode);
292 if (error)
293 goto out;
294
295 if (inherit)
296 error = xfs_set_acl(inode, ACL_TYPE_ACCESS, acl);
297
298out:
299 posix_acl_release(acl);
300 return error;
301}
302
303int
304xfs_acl_chmod(struct inode *inode)
305{
306 struct posix_acl *acl;
307 int error;
308
309 if (S_ISLNK(inode->i_mode))
310 return -EOPNOTSUPP;
311
312 acl = xfs_get_acl(inode, ACL_TYPE_ACCESS);
313 if (IS_ERR(acl) || !acl)
314 return PTR_ERR(acl);
315
316 error = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
317 if (error)
318 return error;
319
320 error = xfs_set_acl(inode, ACL_TYPE_ACCESS, acl);
321 posix_acl_release(acl);
322 return error;
323}
324
325static int
326xfs_xattr_acl_get(struct dentry *dentry, const char *name,
327 void *value, size_t size, int type)
328{
329 struct posix_acl *acl;
330 int error;
331
332 acl = xfs_get_acl(dentry->d_inode, type);
333 if (IS_ERR(acl))
334 return PTR_ERR(acl);
335 if (acl == NULL)
336 return -ENODATA;
337
338 error = posix_acl_to_xattr(acl, value, size);
339 posix_acl_release(acl);
340
341 return error;
342}
343
344static int
345xfs_xattr_acl_set(struct dentry *dentry, const char *name,
346 const void *value, size_t size, int flags, int type)
347{
348 struct inode *inode = dentry->d_inode;
349 struct posix_acl *acl = NULL;
350 int error = 0;
351
352 if (flags & XATTR_CREATE)
353 return -EINVAL;
354 if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
355 return value ? -EACCES : 0;
356 if ((current_fsuid() != inode->i_uid) && !capable(CAP_FOWNER))
357 return -EPERM;
358
359 if (!value)
360 goto set_acl;
361
362 acl = posix_acl_from_xattr(value, size);
363 if (!acl) {
364 /*
365 * acl_set_file(3) may request that we set default ACLs with
366 * zero length -- defend (gracefully) against that here.
367 */
368 goto out;
369 }
370 if (IS_ERR(acl)) {
371 error = PTR_ERR(acl);
372 goto out;
373 }
374
375 error = posix_acl_valid(acl);
376 if (error)
377 goto out_release;
378
379 error = -EINVAL;
380 if (acl->a_count > XFS_ACL_MAX_ENTRIES)
381 goto out_release;
382
383 if (type == ACL_TYPE_ACCESS) {
384 umode_t mode = inode->i_mode;
385 error = posix_acl_equiv_mode(acl, &mode);
386
387 if (error <= 0) {
388 posix_acl_release(acl);
389 acl = NULL;
390
391 if (error < 0)
392 return error;
393 }
394
395 error = xfs_set_mode(inode, mode);
396 if (error)
397 goto out_release;
398 }
399
400 set_acl:
401 error = xfs_set_acl(inode, type, acl);
402 out_release:
403 posix_acl_release(acl);
404 out:
405 return error;
406}
407
408const struct xattr_handler xfs_xattr_acl_access_handler = {
409 .prefix = POSIX_ACL_XATTR_ACCESS,
410 .flags = ACL_TYPE_ACCESS,
411 .get = xfs_xattr_acl_get,
412 .set = xfs_xattr_acl_set,
413};
414
415const struct xattr_handler xfs_xattr_acl_default_handler = {
416 .prefix = POSIX_ACL_XATTR_DEFAULT,
417 .flags = ACL_TYPE_DEFAULT,
418 .get = xfs_xattr_acl_get,
419 .set = xfs_xattr_acl_set,
420};
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_format.h"
20#include "xfs_log_format.h"
21#include "xfs_trans_resv.h"
22#include "xfs_mount.h"
23#include "xfs_inode.h"
24#include "xfs_acl.h"
25#include "xfs_attr.h"
26#include "xfs_trace.h"
27#include <linux/slab.h>
28#include <linux/xattr.h>
29#include <linux/posix_acl_xattr.h>
30
31
32/*
33 * Locking scheme:
34 * - all ACL updates are protected by inode->i_mutex, which is taken before
35 * calling into this file.
36 */
37
38STATIC struct posix_acl *
39xfs_acl_from_disk(
40 const struct xfs_acl *aclp,
41 int len,
42 int max_entries)
43{
44 struct posix_acl_entry *acl_e;
45 struct posix_acl *acl;
46 const struct xfs_acl_entry *ace;
47 unsigned int count, i;
48
49 if (len < sizeof(*aclp))
50 return ERR_PTR(-EFSCORRUPTED);
51 count = be32_to_cpu(aclp->acl_cnt);
52 if (count > max_entries || XFS_ACL_SIZE(count) != len)
53 return ERR_PTR(-EFSCORRUPTED);
54
55 acl = posix_acl_alloc(count, GFP_KERNEL);
56 if (!acl)
57 return ERR_PTR(-ENOMEM);
58
59 for (i = 0; i < count; i++) {
60 acl_e = &acl->a_entries[i];
61 ace = &aclp->acl_entry[i];
62
63 /*
64 * The tag is 32 bits on disk and 16 bits in core.
65 *
66 * Because every access to it goes through the core
67 * format first this is not a problem.
68 */
69 acl_e->e_tag = be32_to_cpu(ace->ae_tag);
70 acl_e->e_perm = be16_to_cpu(ace->ae_perm);
71
72 switch (acl_e->e_tag) {
73 case ACL_USER:
74 acl_e->e_uid = xfs_uid_to_kuid(be32_to_cpu(ace->ae_id));
75 break;
76 case ACL_GROUP:
77 acl_e->e_gid = xfs_gid_to_kgid(be32_to_cpu(ace->ae_id));
78 break;
79 case ACL_USER_OBJ:
80 case ACL_GROUP_OBJ:
81 case ACL_MASK:
82 case ACL_OTHER:
83 break;
84 default:
85 goto fail;
86 }
87 }
88 return acl;
89
90fail:
91 posix_acl_release(acl);
92 return ERR_PTR(-EINVAL);
93}
94
95STATIC void
96xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl)
97{
98 const struct posix_acl_entry *acl_e;
99 struct xfs_acl_entry *ace;
100 int i;
101
102 aclp->acl_cnt = cpu_to_be32(acl->a_count);
103 for (i = 0; i < acl->a_count; i++) {
104 ace = &aclp->acl_entry[i];
105 acl_e = &acl->a_entries[i];
106
107 ace->ae_tag = cpu_to_be32(acl_e->e_tag);
108 switch (acl_e->e_tag) {
109 case ACL_USER:
110 ace->ae_id = cpu_to_be32(xfs_kuid_to_uid(acl_e->e_uid));
111 break;
112 case ACL_GROUP:
113 ace->ae_id = cpu_to_be32(xfs_kgid_to_gid(acl_e->e_gid));
114 break;
115 default:
116 ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID);
117 break;
118 }
119
120 ace->ae_perm = cpu_to_be16(acl_e->e_perm);
121 }
122}
123
124struct posix_acl *
125xfs_get_acl(struct inode *inode, int type)
126{
127 struct xfs_inode *ip = XFS_I(inode);
128 struct posix_acl *acl = NULL;
129 struct xfs_acl *xfs_acl;
130 unsigned char *ea_name;
131 int error;
132 int len;
133
134 trace_xfs_get_acl(ip);
135
136 switch (type) {
137 case ACL_TYPE_ACCESS:
138 ea_name = SGI_ACL_FILE;
139 break;
140 case ACL_TYPE_DEFAULT:
141 ea_name = SGI_ACL_DEFAULT;
142 break;
143 default:
144 BUG();
145 }
146
147 /*
148 * If we have a cached ACLs value just return it, not need to
149 * go out to the disk.
150 */
151 len = XFS_ACL_MAX_SIZE(ip->i_mount);
152 xfs_acl = kmem_zalloc_large(len, KM_SLEEP);
153 if (!xfs_acl)
154 return ERR_PTR(-ENOMEM);
155
156 error = xfs_attr_get(ip, ea_name, (unsigned char *)xfs_acl,
157 &len, ATTR_ROOT);
158 if (error) {
159 /*
160 * If the attribute doesn't exist make sure we have a negative
161 * cache entry, for any other error assume it is transient and
162 * leave the cache entry as ACL_NOT_CACHED.
163 */
164 if (error == -ENOATTR)
165 goto out_update_cache;
166 acl = ERR_PTR(error);
167 goto out;
168 }
169
170 acl = xfs_acl_from_disk(xfs_acl, len, XFS_ACL_MAX_ENTRIES(ip->i_mount));
171 if (IS_ERR(acl))
172 goto out;
173
174out_update_cache:
175 set_cached_acl(inode, type, acl);
176out:
177 kmem_free(xfs_acl);
178 return acl;
179}
180
181STATIC int
182__xfs_set_acl(struct inode *inode, int type, struct posix_acl *acl)
183{
184 struct xfs_inode *ip = XFS_I(inode);
185 unsigned char *ea_name;
186 int error;
187
188 switch (type) {
189 case ACL_TYPE_ACCESS:
190 ea_name = SGI_ACL_FILE;
191 break;
192 case ACL_TYPE_DEFAULT:
193 if (!S_ISDIR(inode->i_mode))
194 return acl ? -EACCES : 0;
195 ea_name = SGI_ACL_DEFAULT;
196 break;
197 default:
198 return -EINVAL;
199 }
200
201 if (acl) {
202 struct xfs_acl *xfs_acl;
203 int len = XFS_ACL_MAX_SIZE(ip->i_mount);
204
205 xfs_acl = kmem_zalloc_large(len, KM_SLEEP);
206 if (!xfs_acl)
207 return -ENOMEM;
208
209 xfs_acl_to_disk(xfs_acl, acl);
210
211 /* subtract away the unused acl entries */
212 len -= sizeof(struct xfs_acl_entry) *
213 (XFS_ACL_MAX_ENTRIES(ip->i_mount) - acl->a_count);
214
215 error = xfs_attr_set(ip, ea_name, (unsigned char *)xfs_acl,
216 len, ATTR_ROOT);
217
218 kmem_free(xfs_acl);
219 } else {
220 /*
221 * A NULL ACL argument means we want to remove the ACL.
222 */
223 error = xfs_attr_remove(ip, ea_name, ATTR_ROOT);
224
225 /*
226 * If the attribute didn't exist to start with that's fine.
227 */
228 if (error == -ENOATTR)
229 error = 0;
230 }
231
232 if (!error)
233 set_cached_acl(inode, type, acl);
234 return error;
235}
236
237static int
238xfs_set_mode(struct inode *inode, umode_t mode)
239{
240 int error = 0;
241
242 if (mode != inode->i_mode) {
243 struct iattr iattr;
244
245 iattr.ia_valid = ATTR_MODE | ATTR_CTIME;
246 iattr.ia_mode = mode;
247 iattr.ia_ctime = current_fs_time(inode->i_sb);
248
249 error = xfs_setattr_nonsize(XFS_I(inode), &iattr, XFS_ATTR_NOACL);
250 }
251
252 return error;
253}
254
255int
256xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
257{
258 int error = 0;
259
260 if (!acl)
261 goto set_acl;
262
263 error = -E2BIG;
264 if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb)))
265 return error;
266
267 if (type == ACL_TYPE_ACCESS) {
268 umode_t mode = inode->i_mode;
269 error = posix_acl_equiv_mode(acl, &mode);
270
271 if (error <= 0) {
272 acl = NULL;
273
274 if (error < 0)
275 return error;
276 }
277
278 error = xfs_set_mode(inode, mode);
279 if (error)
280 return error;
281 }
282
283 set_acl:
284 return __xfs_set_acl(inode, type, acl);
285}