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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// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2008, Christoph Hellwig
4 * All Rights Reserved.
5 */
6#include "xfs.h"
7#include "xfs_shared.h"
8#include "xfs_format.h"
9#include "xfs_log_format.h"
10#include "xfs_trans_resv.h"
11#include "xfs_mount.h"
12#include "xfs_inode.h"
13#include "xfs_attr.h"
14#include "xfs_trace.h"
15#include "xfs_error.h"
16#include "xfs_acl.h"
17#include "xfs_da_format.h"
18#include "xfs_da_btree.h"
19
20#include <linux/posix_acl_xattr.h>
21
22/*
23 * Locking scheme:
24 * - all ACL updates are protected by inode->i_mutex, which is taken before
25 * calling into this file.
26 */
27
28STATIC struct posix_acl *
29xfs_acl_from_disk(
30 struct xfs_mount *mp,
31 const struct xfs_acl *aclp,
32 int len,
33 int max_entries)
34{
35 struct posix_acl_entry *acl_e;
36 struct posix_acl *acl;
37 const struct xfs_acl_entry *ace;
38 unsigned int count, i;
39
40 if (len < sizeof(*aclp)) {
41 XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp,
42 len);
43 return ERR_PTR(-EFSCORRUPTED);
44 }
45
46 count = be32_to_cpu(aclp->acl_cnt);
47 if (count > max_entries || XFS_ACL_SIZE(count) != len) {
48 XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp,
49 len);
50 return ERR_PTR(-EFSCORRUPTED);
51 }
52
53 acl = posix_acl_alloc(count, GFP_KERNEL);
54 if (!acl)
55 return ERR_PTR(-ENOMEM);
56
57 for (i = 0; i < count; i++) {
58 acl_e = &acl->a_entries[i];
59 ace = &aclp->acl_entry[i];
60
61 /*
62 * The tag is 32 bits on disk and 16 bits in core.
63 *
64 * Because every access to it goes through the core
65 * format first this is not a problem.
66 */
67 acl_e->e_tag = be32_to_cpu(ace->ae_tag);
68 acl_e->e_perm = be16_to_cpu(ace->ae_perm);
69
70 switch (acl_e->e_tag) {
71 case ACL_USER:
72 acl_e->e_uid = make_kuid(&init_user_ns,
73 be32_to_cpu(ace->ae_id));
74 break;
75 case ACL_GROUP:
76 acl_e->e_gid = make_kgid(&init_user_ns,
77 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(
111 from_kuid(&init_user_ns, acl_e->e_uid));
112 break;
113 case ACL_GROUP:
114 ace->ae_id = cpu_to_be32(
115 from_kgid(&init_user_ns, acl_e->e_gid));
116 break;
117 default:
118 ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID);
119 break;
120 }
121
122 ace->ae_perm = cpu_to_be16(acl_e->e_perm);
123 }
124}
125
126struct posix_acl *
127xfs_get_acl(struct inode *inode, int type)
128{
129 struct xfs_inode *ip = XFS_I(inode);
130 struct xfs_mount *mp = ip->i_mount;
131 struct posix_acl *acl = NULL;
132 struct xfs_da_args args = {
133 .dp = ip,
134 .attr_filter = XFS_ATTR_ROOT,
135 .valuelen = XFS_ACL_MAX_SIZE(mp),
136 };
137 int error;
138
139 trace_xfs_get_acl(ip);
140
141 switch (type) {
142 case ACL_TYPE_ACCESS:
143 args.name = SGI_ACL_FILE;
144 break;
145 case ACL_TYPE_DEFAULT:
146 args.name = SGI_ACL_DEFAULT;
147 break;
148 default:
149 BUG();
150 }
151 args.namelen = strlen(args.name);
152
153 /*
154 * If the attribute doesn't exist make sure we have a negative cache
155 * entry, for any other error assume it is transient.
156 */
157 error = xfs_attr_get(&args);
158 if (!error) {
159 acl = xfs_acl_from_disk(mp, args.value, args.valuelen,
160 XFS_ACL_MAX_ENTRIES(mp));
161 } else if (error != -ENOATTR) {
162 acl = ERR_PTR(error);
163 }
164
165 kmem_free(args.value);
166 return acl;
167}
168
169int
170__xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
171{
172 struct xfs_inode *ip = XFS_I(inode);
173 struct xfs_da_args args = {
174 .dp = ip,
175 .attr_filter = XFS_ATTR_ROOT,
176 };
177 int error;
178
179 switch (type) {
180 case ACL_TYPE_ACCESS:
181 args.name = SGI_ACL_FILE;
182 break;
183 case ACL_TYPE_DEFAULT:
184 if (!S_ISDIR(inode->i_mode))
185 return acl ? -EACCES : 0;
186 args.name = SGI_ACL_DEFAULT;
187 break;
188 default:
189 return -EINVAL;
190 }
191 args.namelen = strlen(args.name);
192
193 if (acl) {
194 args.valuelen = XFS_ACL_SIZE(acl->a_count);
195 args.value = kmem_zalloc_large(args.valuelen, 0);
196 if (!args.value)
197 return -ENOMEM;
198 xfs_acl_to_disk(args.value, acl);
199 }
200
201 error = xfs_attr_set(&args);
202 kmem_free(args.value);
203
204 /*
205 * If the attribute didn't exist to start with that's fine.
206 */
207 if (!acl && error == -ENOATTR)
208 error = 0;
209 if (!error)
210 set_cached_acl(inode, type, acl);
211 return error;
212}
213
214static int
215xfs_set_mode(struct inode *inode, umode_t mode)
216{
217 int error = 0;
218
219 if (mode != inode->i_mode) {
220 struct iattr iattr;
221
222 iattr.ia_valid = ATTR_MODE | ATTR_CTIME;
223 iattr.ia_mode = mode;
224 iattr.ia_ctime = current_time(inode);
225
226 error = xfs_setattr_nonsize(XFS_I(inode), &iattr, XFS_ATTR_NOACL);
227 }
228
229 return error;
230}
231
232int
233xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
234{
235 umode_t mode;
236 bool set_mode = false;
237 int error = 0;
238
239 if (!acl)
240 goto set_acl;
241
242 error = -E2BIG;
243 if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb)))
244 return error;
245
246 if (type == ACL_TYPE_ACCESS) {
247 error = posix_acl_update_mode(inode, &mode, &acl);
248 if (error)
249 return error;
250 set_mode = true;
251 }
252
253 set_acl:
254 error = __xfs_set_acl(inode, acl, type);
255 if (error)
256 return error;
257
258 /*
259 * We set the mode after successfully updating the ACL xattr because the
260 * xattr update can fail at ENOSPC and we don't want to change the mode
261 * if the ACL update hasn't been applied.
262 */
263 if (set_mode)
264 error = xfs_set_mode(inode, mode);
265
266 return error;
267}
268
269/*
270 * Invalidate any cached ACLs if the user has bypassed the ACL interface.
271 * We don't validate the content whatsoever so it is caller responsibility to
272 * provide data in valid format and ensure i_mode is consistent.
273 */
274void
275xfs_forget_acl(
276 struct inode *inode,
277 const char *name)
278{
279 if (!strcmp(name, SGI_ACL_FILE))
280 forget_cached_acl(inode, ACL_TYPE_ACCESS);
281 else if (!strcmp(name, SGI_ACL_DEFAULT))
282 forget_cached_acl(inode, ACL_TYPE_DEFAULT);
283}