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CommitLineData
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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"
0b1b213f 24#include "xfs_trace.h"
5a0e3ad6 25#include <linux/slab.h>
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26#include <linux/xattr.h>
27#include <linux/posix_acl_xattr.h>
28
29
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30/*
31 * Locking scheme:
32 * - all ACL updates are protected by inode->i_mutex, which is taken before
33 * calling into this file.
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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
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103struct posix_acl *
104xfs_get_acl(struct inode *inode, int type)
105{
106 struct xfs_inode *ip = XFS_I(inode);
1cbd20d8 107 struct posix_acl *acl;
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108 struct xfs_acl *xfs_acl;
109 int len = sizeof(struct xfs_acl);
a9273ca5 110 unsigned char *ea_name;
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111 int error;
112
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113 acl = get_cached_acl(inode, type);
114 if (acl != ACL_NOT_CACHED)
115 return acl;
116
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117 switch (type) {
118 case ACL_TYPE_ACCESS:
119 ea_name = SGI_ACL_FILE;
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120 break;
121 case ACL_TYPE_DEFAULT:
122 ea_name = SGI_ACL_DEFAULT;
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123 break;
124 default:
1cbd20d8 125 BUG();
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126 }
127
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128 /*
129 * If we have a cached ACLs value just return it, not need to
130 * go out to the disk.
131 */
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132
133 xfs_acl = kzalloc(sizeof(struct xfs_acl), GFP_KERNEL);
134 if (!xfs_acl)
135 return ERR_PTR(-ENOMEM);
136
a9273ca5
DC
137 error = -xfs_attr_get(ip, ea_name, (unsigned char *)xfs_acl,
138 &len, ATTR_ROOT);
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139 if (error) {
140 /*
141 * If the attribute doesn't exist make sure we have a negative
142 * cache entry, for any other error assume it is transient and
1cbd20d8 143 * leave the cache entry as ACL_NOT_CACHED.
ef14f0c1
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144 */
145 if (error == -ENOATTR) {
146 acl = NULL;
147 goto out_update_cache;
148 }
149 goto out;
150 }
151
152 acl = xfs_acl_from_disk(xfs_acl);
153 if (IS_ERR(acl))
154 goto out;
155
156 out_update_cache:
1cbd20d8 157 set_cached_acl(inode, type, acl);
ef14f0c1
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158 out:
159 kfree(xfs_acl);
160 return acl;
161}
162
163STATIC int
164xfs_set_acl(struct inode *inode, int type, struct posix_acl *acl)
165{
166 struct xfs_inode *ip = XFS_I(inode);
a9273ca5 167 unsigned char *ea_name;
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168 int error;
169
170 if (S_ISLNK(inode->i_mode))
171 return -EOPNOTSUPP;
172
173 switch (type) {
174 case ACL_TYPE_ACCESS:
175 ea_name = SGI_ACL_FILE;
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176 break;
177 case ACL_TYPE_DEFAULT:
178 if (!S_ISDIR(inode->i_mode))
179 return acl ? -EACCES : 0;
180 ea_name = SGI_ACL_DEFAULT;
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181 break;
182 default:
183 return -EINVAL;
184 }
185
186 if (acl) {
187 struct xfs_acl *xfs_acl;
188 int len;
189
190 xfs_acl = kzalloc(sizeof(struct xfs_acl), GFP_KERNEL);
191 if (!xfs_acl)
192 return -ENOMEM;
193
194 xfs_acl_to_disk(xfs_acl, acl);
195 len = sizeof(struct xfs_acl) -
196 (sizeof(struct xfs_acl_entry) *
197 (XFS_ACL_MAX_ENTRIES - acl->a_count));
198
a9273ca5 199 error = -xfs_attr_set(ip, ea_name, (unsigned char *)xfs_acl,
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200 len, ATTR_ROOT);
201
202 kfree(xfs_acl);
203 } else {
204 /*
205 * A NULL ACL argument means we want to remove the ACL.
206 */
207 error = -xfs_attr_remove(ip, ea_name, ATTR_ROOT);
208
209 /*
210 * If the attribute didn't exist to start with that's fine.
211 */
212 if (error == -ENOATTR)
213 error = 0;
214 }
215
216 if (!error)
1cbd20d8 217 set_cached_acl(inode, type, acl);
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218 return error;
219}
220
221int
7e40145e 222xfs_check_acl(struct inode *inode, int mask)
ef14f0c1 223{
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224 struct posix_acl *acl;
225 int error = -EAGAIN;
226
6311b108 227 trace_xfs_check_acl(XFS_I(inode));
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228
229 acl = xfs_get_acl(inode, ACL_TYPE_ACCESS);
230 if (IS_ERR(acl))
231 return PTR_ERR(acl);
232 if (acl) {
233 error = posix_acl_permission(inode, acl, mask);
234 posix_acl_release(acl);
235 }
236
237 return error;
238}
239
240static int
241xfs_set_mode(struct inode *inode, mode_t mode)
242{
243 int error = 0;
244
245 if (mode != inode->i_mode) {
246 struct iattr iattr;
247
d6d59bad 248 iattr.ia_valid = ATTR_MODE | ATTR_CTIME;
ef14f0c1 249 iattr.ia_mode = mode;
d6d59bad 250 iattr.ia_ctime = current_fs_time(inode->i_sb);
ef14f0c1 251
c4ed4243 252 error = -xfs_setattr_nonsize(XFS_I(inode), &iattr, XFS_ATTR_NOACL);
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253 }
254
255 return error;
256}
257
258static int
a9273ca5 259xfs_acl_exists(struct inode *inode, unsigned char *name)
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260{
261 int len = sizeof(struct xfs_acl);
262
263 return (xfs_attr_get(XFS_I(inode), name, NULL, &len,
264 ATTR_ROOT|ATTR_KERNOVAL) == 0);
265}
266
267int
268posix_acl_access_exists(struct inode *inode)
269{
270 return xfs_acl_exists(inode, SGI_ACL_FILE);
271}
272
273int
274posix_acl_default_exists(struct inode *inode)
275{
276 if (!S_ISDIR(inode->i_mode))
277 return 0;
278 return xfs_acl_exists(inode, SGI_ACL_DEFAULT);
279}
280
281/*
282 * No need for i_mutex because the inode is not yet exposed to the VFS.
283 */
284int
826cae2f 285xfs_inherit_acl(struct inode *inode, struct posix_acl *acl)
ef14f0c1 286{
826cae2f 287 mode_t mode = inode->i_mode;
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288 int error = 0, inherit = 0;
289
290 if (S_ISDIR(inode->i_mode)) {
826cae2f 291 error = xfs_set_acl(inode, ACL_TYPE_DEFAULT, acl);
ef14f0c1 292 if (error)
826cae2f 293 goto out;
ef14f0c1
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294 }
295
826cae2f 296 error = posix_acl_create(&acl, GFP_KERNEL, &mode);
ef14f0c1 297 if (error < 0)
826cae2f 298 return error;
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299
300 /*
826cae2f 301 * If posix_acl_create returns a positive value we need to
ef14f0c1
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302 * inherit a permission that can't be represented using the Unix
303 * mode bits and we actually need to set an ACL.
304 */
305 if (error > 0)
306 inherit = 1;
307
308 error = xfs_set_mode(inode, mode);
309 if (error)
826cae2f 310 goto out;
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311
312 if (inherit)
826cae2f 313 error = xfs_set_acl(inode, ACL_TYPE_ACCESS, acl);
ef14f0c1 314
826cae2f
AV
315out:
316 posix_acl_release(acl);
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317 return error;
318}
319
320int
321xfs_acl_chmod(struct inode *inode)
322{
bc26ab5f 323 struct posix_acl *acl;
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324 int error;
325
326 if (S_ISLNK(inode->i_mode))
327 return -EOPNOTSUPP;
328
329 acl = xfs_get_acl(inode, ACL_TYPE_ACCESS);
330 if (IS_ERR(acl) || !acl)
331 return PTR_ERR(acl);
332
bc26ab5f
AV
333 error = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
334 if (error)
335 return error;
ef14f0c1 336
bc26ab5f
AV
337 error = xfs_set_acl(inode, ACL_TYPE_ACCESS, acl);
338 posix_acl_release(acl);
ef14f0c1
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339 return error;
340}
341
ef14f0c1 342static int
431547b3
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343xfs_xattr_acl_get(struct dentry *dentry, const char *name,
344 void *value, size_t size, int type)
ef14f0c1
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345{
346 struct posix_acl *acl;
431547b3 347 int error;
ef14f0c1 348
431547b3 349 acl = xfs_get_acl(dentry->d_inode, type);
ef14f0c1
CH
350 if (IS_ERR(acl))
351 return PTR_ERR(acl);
352 if (acl == NULL)
353 return -ENODATA;
354
355 error = posix_acl_to_xattr(acl, value, size);
356 posix_acl_release(acl);
357
358 return error;
359}
360
361static int
431547b3
CH
362xfs_xattr_acl_set(struct dentry *dentry, const char *name,
363 const void *value, size_t size, int flags, int type)
ef14f0c1 364{
431547b3 365 struct inode *inode = dentry->d_inode;
ef14f0c1 366 struct posix_acl *acl = NULL;
431547b3 367 int error = 0;
ef14f0c1 368
ef14f0c1
CH
369 if (flags & XATTR_CREATE)
370 return -EINVAL;
371 if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
372 return value ? -EACCES : 0;
373 if ((current_fsuid() != inode->i_uid) && !capable(CAP_FOWNER))
374 return -EPERM;
375
376 if (!value)
377 goto set_acl;
378
379 acl = posix_acl_from_xattr(value, size);
380 if (!acl) {
381 /*
382 * acl_set_file(3) may request that we set default ACLs with
383 * zero length -- defend (gracefully) against that here.
384 */
385 goto out;
386 }
387 if (IS_ERR(acl)) {
388 error = PTR_ERR(acl);
389 goto out;
390 }
391
392 error = posix_acl_valid(acl);
393 if (error)
394 goto out_release;
395
396 error = -EINVAL;
397 if (acl->a_count > XFS_ACL_MAX_ENTRIES)
398 goto out_release;
399
400 if (type == ACL_TYPE_ACCESS) {
401 mode_t mode = inode->i_mode;
402 error = posix_acl_equiv_mode(acl, &mode);
403
404 if (error <= 0) {
405 posix_acl_release(acl);
406 acl = NULL;
407
408 if (error < 0)
409 return error;
410 }
411
412 error = xfs_set_mode(inode, mode);
413 if (error)
414 goto out_release;
415 }
416
417 set_acl:
418 error = xfs_set_acl(inode, type, acl);
419 out_release:
420 posix_acl_release(acl);
421 out:
422 return error;
423}
424
46e58764 425const struct xattr_handler xfs_xattr_acl_access_handler = {
431547b3
CH
426 .prefix = POSIX_ACL_XATTR_ACCESS,
427 .flags = ACL_TYPE_ACCESS,
428 .get = xfs_xattr_acl_get,
429 .set = xfs_xattr_acl_set,
430};
431
46e58764 432const struct xattr_handler xfs_xattr_acl_default_handler = {
431547b3
CH
433 .prefix = POSIX_ACL_XATTR_DEFAULT,
434 .flags = ACL_TYPE_DEFAULT,
435 .get = xfs_xattr_acl_get,
436 .set = xfs_xattr_acl_set,
ef14f0c1 437};