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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_da_format.h"
14#include "xfs_da_btree.h"
15#include "xfs_attr.h"
16#include "xfs_trace.h"
17#include "xfs_error.h"
18#include "xfs_acl.h"
19#include "xfs_trans.h"
20#include "xfs_xattr.h"
21
22#include <linux/posix_acl_xattr.h>
23
24/*
25 * Locking scheme:
26 * - all ACL updates are protected by inode->i_mutex, which is taken before
27 * calling into this file.
28 */
29
30STATIC struct posix_acl *
31xfs_acl_from_disk(
32 struct xfs_mount *mp,
33 const struct xfs_acl *aclp,
34 int len,
35 int max_entries)
36{
37 struct posix_acl_entry *acl_e;
38 struct posix_acl *acl;
39 const struct xfs_acl_entry *ace;
40 unsigned int count, i;
41
42 if (len < sizeof(*aclp)) {
43 XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp,
44 len);
45 return ERR_PTR(-EFSCORRUPTED);
46 }
47
48 count = be32_to_cpu(aclp->acl_cnt);
49 if (count > max_entries || XFS_ACL_SIZE(count) != len) {
50 XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp,
51 len);
52 return ERR_PTR(-EFSCORRUPTED);
53 }
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 = make_kuid(&init_user_ns,
75 be32_to_cpu(ace->ae_id));
76 break;
77 case ACL_GROUP:
78 acl_e->e_gid = make_kgid(&init_user_ns,
79 be32_to_cpu(ace->ae_id));
80 break;
81 case ACL_USER_OBJ:
82 case ACL_GROUP_OBJ:
83 case ACL_MASK:
84 case ACL_OTHER:
85 break;
86 default:
87 goto fail;
88 }
89 }
90 return acl;
91
92fail:
93 posix_acl_release(acl);
94 return ERR_PTR(-EINVAL);
95}
96
97STATIC void
98xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl)
99{
100 const struct posix_acl_entry *acl_e;
101 struct xfs_acl_entry *ace;
102 int i;
103
104 aclp->acl_cnt = cpu_to_be32(acl->a_count);
105 for (i = 0; i < acl->a_count; i++) {
106 ace = &aclp->acl_entry[i];
107 acl_e = &acl->a_entries[i];
108
109 ace->ae_tag = cpu_to_be32(acl_e->e_tag);
110 switch (acl_e->e_tag) {
111 case ACL_USER:
112 ace->ae_id = cpu_to_be32(
113 from_kuid(&init_user_ns, acl_e->e_uid));
114 break;
115 case ACL_GROUP:
116 ace->ae_id = cpu_to_be32(
117 from_kgid(&init_user_ns, acl_e->e_gid));
118 break;
119 default:
120 ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID);
121 break;
122 }
123
124 ace->ae_perm = cpu_to_be16(acl_e->e_perm);
125 }
126}
127
128struct posix_acl *
129xfs_get_acl(struct inode *inode, int type, bool rcu)
130{
131 struct xfs_inode *ip = XFS_I(inode);
132 struct xfs_mount *mp = ip->i_mount;
133 struct posix_acl *acl = NULL;
134 struct xfs_da_args args = {
135 .dp = ip,
136 .attr_filter = XFS_ATTR_ROOT,
137 .valuelen = XFS_ACL_MAX_SIZE(mp),
138 };
139 int error;
140
141 if (rcu)
142 return ERR_PTR(-ECHILD);
143
144 trace_xfs_get_acl(ip);
145
146 switch (type) {
147 case ACL_TYPE_ACCESS:
148 args.name = SGI_ACL_FILE;
149 break;
150 case ACL_TYPE_DEFAULT:
151 args.name = SGI_ACL_DEFAULT;
152 break;
153 default:
154 BUG();
155 }
156 args.namelen = strlen(args.name);
157
158 /*
159 * If the attribute doesn't exist make sure we have a negative cache
160 * entry, for any other error assume it is transient.
161 */
162 error = xfs_attr_get(&args);
163 if (!error) {
164 acl = xfs_acl_from_disk(mp, args.value, args.valuelen,
165 XFS_ACL_MAX_ENTRIES(mp));
166 } else if (error != -ENOATTR) {
167 acl = ERR_PTR(error);
168 }
169
170 kvfree(args.value);
171 return acl;
172}
173
174int
175__xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
176{
177 struct xfs_inode *ip = XFS_I(inode);
178 struct xfs_da_args args = {
179 .dp = ip,
180 .attr_filter = XFS_ATTR_ROOT,
181 };
182 int error;
183
184 switch (type) {
185 case ACL_TYPE_ACCESS:
186 args.name = SGI_ACL_FILE;
187 break;
188 case ACL_TYPE_DEFAULT:
189 if (!S_ISDIR(inode->i_mode))
190 return acl ? -EACCES : 0;
191 args.name = SGI_ACL_DEFAULT;
192 break;
193 default:
194 return -EINVAL;
195 }
196 args.namelen = strlen(args.name);
197
198 if (acl) {
199 args.valuelen = XFS_ACL_SIZE(acl->a_count);
200 args.value = kvzalloc(args.valuelen, GFP_KERNEL);
201 if (!args.value)
202 return -ENOMEM;
203 xfs_acl_to_disk(args.value, acl);
204 error = xfs_attr_change(&args, XFS_ATTRUPDATE_UPSERT);
205 kvfree(args.value);
206 } else {
207 error = xfs_attr_change(&args, XFS_ATTRUPDATE_REMOVE);
208 /*
209 * If the attribute didn't exist to start with that's fine.
210 */
211 if (error == -ENOATTR)
212 error = 0;
213 }
214
215 if (!error)
216 set_cached_acl(inode, type, acl);
217 return error;
218}
219
220static int
221xfs_acl_set_mode(
222 struct inode *inode,
223 umode_t mode)
224{
225 struct xfs_inode *ip = XFS_I(inode);
226 struct xfs_mount *mp = ip->i_mount;
227 struct xfs_trans *tp;
228 int error;
229
230 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp);
231 if (error)
232 return error;
233
234 xfs_ilock(ip, XFS_ILOCK_EXCL);
235 xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
236 inode->i_mode = mode;
237 inode_set_ctime_current(inode);
238 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
239
240 if (xfs_has_wsync(mp))
241 xfs_trans_set_sync(tp);
242 return xfs_trans_commit(tp);
243}
244
245int
246xfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
247 struct posix_acl *acl, int type)
248{
249 umode_t mode;
250 bool set_mode = false;
251 int error = 0;
252 struct inode *inode = d_inode(dentry);
253
254 if (!acl)
255 goto set_acl;
256
257 error = -E2BIG;
258 if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb)))
259 return error;
260
261 if (type == ACL_TYPE_ACCESS) {
262 error = posix_acl_update_mode(idmap, inode, &mode, &acl);
263 if (error)
264 return error;
265 set_mode = true;
266 }
267
268 set_acl:
269 /*
270 * We set the mode after successfully updating the ACL xattr because the
271 * xattr update can fail at ENOSPC and we don't want to change the mode
272 * if the ACL update hasn't been applied.
273 */
274 error = __xfs_set_acl(inode, acl, type);
275 if (!error && set_mode && mode != inode->i_mode)
276 error = xfs_acl_set_mode(inode, mode);
277 return error;
278}
279
280/*
281 * Invalidate any cached ACLs if the user has bypassed the ACL interface.
282 * We don't validate the content whatsoever so it is caller responsibility to
283 * provide data in valid format and ensure i_mode is consistent.
284 */
285void
286xfs_forget_acl(
287 struct inode *inode,
288 const char *name)
289{
290 if (!strcmp(name, SGI_ACL_FILE))
291 forget_cached_acl(inode, ACL_TYPE_ACCESS);
292 else if (!strcmp(name, SGI_ACL_DEFAULT))
293 forget_cached_acl(inode, ACL_TYPE_DEFAULT);
294}
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 unsigned int count, i;
43
44 count = be32_to_cpu(aclp->acl_cnt);
45 if (count > XFS_ACL_MAX_ENTRIES)
46 return ERR_PTR(-EFSCORRUPTED);
47
48 acl = posix_acl_alloc(count, GFP_KERNEL);
49 if (!acl)
50 return ERR_PTR(-ENOMEM);
51
52 for (i = 0; i < count; i++) {
53 acl_e = &acl->a_entries[i];
54 ace = &aclp->acl_entry[i];
55
56 /*
57 * The tag is 32 bits on disk and 16 bits in core.
58 *
59 * Because every access to it goes through the core
60 * format first this is not a problem.
61 */
62 acl_e->e_tag = be32_to_cpu(ace->ae_tag);
63 acl_e->e_perm = be16_to_cpu(ace->ae_perm);
64
65 switch (acl_e->e_tag) {
66 case ACL_USER:
67 case ACL_GROUP:
68 acl_e->e_id = be32_to_cpu(ace->ae_id);
69 break;
70 case ACL_USER_OBJ:
71 case ACL_GROUP_OBJ:
72 case ACL_MASK:
73 case ACL_OTHER:
74 acl_e->e_id = ACL_UNDEFINED_ID;
75 break;
76 default:
77 goto fail;
78 }
79 }
80 return acl;
81
82fail:
83 posix_acl_release(acl);
84 return ERR_PTR(-EINVAL);
85}
86
87STATIC void
88xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl)
89{
90 const struct posix_acl_entry *acl_e;
91 struct xfs_acl_entry *ace;
92 int i;
93
94 aclp->acl_cnt = cpu_to_be32(acl->a_count);
95 for (i = 0; i < acl->a_count; i++) {
96 ace = &aclp->acl_entry[i];
97 acl_e = &acl->a_entries[i];
98
99 ace->ae_tag = cpu_to_be32(acl_e->e_tag);
100 ace->ae_id = cpu_to_be32(acl_e->e_id);
101 ace->ae_perm = cpu_to_be16(acl_e->e_perm);
102 }
103}
104
105struct posix_acl *
106xfs_get_acl(struct inode *inode, int type)
107{
108 struct xfs_inode *ip = XFS_I(inode);
109 struct posix_acl *acl;
110 struct xfs_acl *xfs_acl;
111 int len = sizeof(struct xfs_acl);
112 unsigned char *ea_name;
113 int error;
114
115 acl = get_cached_acl(inode, type);
116 if (acl != ACL_NOT_CACHED)
117 return acl;
118
119 trace_xfs_get_acl(ip);
120
121 switch (type) {
122 case ACL_TYPE_ACCESS:
123 ea_name = SGI_ACL_FILE;
124 break;
125 case ACL_TYPE_DEFAULT:
126 ea_name = SGI_ACL_DEFAULT;
127 break;
128 default:
129 BUG();
130 }
131
132 /*
133 * If we have a cached ACLs value just return it, not need to
134 * go out to the disk.
135 */
136
137 xfs_acl = kzalloc(sizeof(struct xfs_acl), GFP_KERNEL);
138 if (!xfs_acl)
139 return ERR_PTR(-ENOMEM);
140
141 error = -xfs_attr_get(ip, ea_name, (unsigned char *)xfs_acl,
142 &len, ATTR_ROOT);
143 if (error) {
144 /*
145 * If the attribute doesn't exist make sure we have a negative
146 * cache entry, for any other error assume it is transient and
147 * leave the cache entry as ACL_NOT_CACHED.
148 */
149 if (error == -ENOATTR) {
150 acl = NULL;
151 goto out_update_cache;
152 }
153 goto out;
154 }
155
156 acl = xfs_acl_from_disk(xfs_acl);
157 if (IS_ERR(acl))
158 goto out;
159
160 out_update_cache:
161 set_cached_acl(inode, type, acl);
162 out:
163 kfree(xfs_acl);
164 return acl;
165}
166
167STATIC int
168xfs_set_acl(struct inode *inode, int type, struct posix_acl *acl)
169{
170 struct xfs_inode *ip = XFS_I(inode);
171 unsigned char *ea_name;
172 int error;
173
174 if (S_ISLNK(inode->i_mode))
175 return -EOPNOTSUPP;
176
177 switch (type) {
178 case ACL_TYPE_ACCESS:
179 ea_name = SGI_ACL_FILE;
180 break;
181 case ACL_TYPE_DEFAULT:
182 if (!S_ISDIR(inode->i_mode))
183 return acl ? -EACCES : 0;
184 ea_name = SGI_ACL_DEFAULT;
185 break;
186 default:
187 return -EINVAL;
188 }
189
190 if (acl) {
191 struct xfs_acl *xfs_acl;
192 int len;
193
194 xfs_acl = kzalloc(sizeof(struct xfs_acl), GFP_KERNEL);
195 if (!xfs_acl)
196 return -ENOMEM;
197
198 xfs_acl_to_disk(xfs_acl, acl);
199 len = sizeof(struct xfs_acl) -
200 (sizeof(struct xfs_acl_entry) *
201 (XFS_ACL_MAX_ENTRIES - acl->a_count));
202
203 error = -xfs_attr_set(ip, ea_name, (unsigned char *)xfs_acl,
204 len, ATTR_ROOT);
205
206 kfree(xfs_acl);
207 } else {
208 /*
209 * A NULL ACL argument means we want to remove the ACL.
210 */
211 error = -xfs_attr_remove(ip, ea_name, ATTR_ROOT);
212
213 /*
214 * If the attribute didn't exist to start with that's fine.
215 */
216 if (error == -ENOATTR)
217 error = 0;
218 }
219
220 if (!error)
221 set_cached_acl(inode, type, acl);
222 return error;
223}
224
225static int
226xfs_set_mode(struct inode *inode, umode_t mode)
227{
228 int error = 0;
229
230 if (mode != inode->i_mode) {
231 struct iattr iattr;
232
233 iattr.ia_valid = ATTR_MODE | ATTR_CTIME;
234 iattr.ia_mode = mode;
235 iattr.ia_ctime = current_fs_time(inode->i_sb);
236
237 error = -xfs_setattr_nonsize(XFS_I(inode), &iattr, XFS_ATTR_NOACL);
238 }
239
240 return error;
241}
242
243static int
244xfs_acl_exists(struct inode *inode, unsigned char *name)
245{
246 int len = sizeof(struct xfs_acl);
247
248 return (xfs_attr_get(XFS_I(inode), name, NULL, &len,
249 ATTR_ROOT|ATTR_KERNOVAL) == 0);
250}
251
252int
253posix_acl_access_exists(struct inode *inode)
254{
255 return xfs_acl_exists(inode, SGI_ACL_FILE);
256}
257
258int
259posix_acl_default_exists(struct inode *inode)
260{
261 if (!S_ISDIR(inode->i_mode))
262 return 0;
263 return xfs_acl_exists(inode, SGI_ACL_DEFAULT);
264}
265
266/*
267 * No need for i_mutex because the inode is not yet exposed to the VFS.
268 */
269int
270xfs_inherit_acl(struct inode *inode, struct posix_acl *acl)
271{
272 umode_t mode = inode->i_mode;
273 int error = 0, inherit = 0;
274
275 if (S_ISDIR(inode->i_mode)) {
276 error = xfs_set_acl(inode, ACL_TYPE_DEFAULT, acl);
277 if (error)
278 goto out;
279 }
280
281 error = posix_acl_create(&acl, GFP_KERNEL, &mode);
282 if (error < 0)
283 return error;
284
285 /*
286 * If posix_acl_create returns a positive value we need to
287 * inherit a permission that can't be represented using the Unix
288 * mode bits and we actually need to set an ACL.
289 */
290 if (error > 0)
291 inherit = 1;
292
293 error = xfs_set_mode(inode, mode);
294 if (error)
295 goto out;
296
297 if (inherit)
298 error = xfs_set_acl(inode, ACL_TYPE_ACCESS, acl);
299
300out:
301 posix_acl_release(acl);
302 return error;
303}
304
305int
306xfs_acl_chmod(struct inode *inode)
307{
308 struct posix_acl *acl;
309 int error;
310
311 if (S_ISLNK(inode->i_mode))
312 return -EOPNOTSUPP;
313
314 acl = xfs_get_acl(inode, ACL_TYPE_ACCESS);
315 if (IS_ERR(acl) || !acl)
316 return PTR_ERR(acl);
317
318 error = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
319 if (error)
320 return error;
321
322 error = xfs_set_acl(inode, ACL_TYPE_ACCESS, acl);
323 posix_acl_release(acl);
324 return error;
325}
326
327static int
328xfs_xattr_acl_get(struct dentry *dentry, const char *name,
329 void *value, size_t size, int type)
330{
331 struct posix_acl *acl;
332 int error;
333
334 acl = xfs_get_acl(dentry->d_inode, type);
335 if (IS_ERR(acl))
336 return PTR_ERR(acl);
337 if (acl == NULL)
338 return -ENODATA;
339
340 error = posix_acl_to_xattr(acl, value, size);
341 posix_acl_release(acl);
342
343 return error;
344}
345
346static int
347xfs_xattr_acl_set(struct dentry *dentry, const char *name,
348 const void *value, size_t size, int flags, int type)
349{
350 struct inode *inode = dentry->d_inode;
351 struct posix_acl *acl = NULL;
352 int error = 0;
353
354 if (flags & XATTR_CREATE)
355 return -EINVAL;
356 if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
357 return value ? -EACCES : 0;
358 if ((current_fsuid() != inode->i_uid) && !capable(CAP_FOWNER))
359 return -EPERM;
360
361 if (!value)
362 goto set_acl;
363
364 acl = posix_acl_from_xattr(value, size);
365 if (!acl) {
366 /*
367 * acl_set_file(3) may request that we set default ACLs with
368 * zero length -- defend (gracefully) against that here.
369 */
370 goto out;
371 }
372 if (IS_ERR(acl)) {
373 error = PTR_ERR(acl);
374 goto out;
375 }
376
377 error = posix_acl_valid(acl);
378 if (error)
379 goto out_release;
380
381 error = -EINVAL;
382 if (acl->a_count > XFS_ACL_MAX_ENTRIES)
383 goto out_release;
384
385 if (type == ACL_TYPE_ACCESS) {
386 umode_t mode = inode->i_mode;
387 error = posix_acl_equiv_mode(acl, &mode);
388
389 if (error <= 0) {
390 posix_acl_release(acl);
391 acl = NULL;
392
393 if (error < 0)
394 return error;
395 }
396
397 error = xfs_set_mode(inode, mode);
398 if (error)
399 goto out_release;
400 }
401
402 set_acl:
403 error = xfs_set_acl(inode, type, acl);
404 out_release:
405 posix_acl_release(acl);
406 out:
407 return error;
408}
409
410const struct xattr_handler xfs_xattr_acl_access_handler = {
411 .prefix = POSIX_ACL_XATTR_ACCESS,
412 .flags = ACL_TYPE_ACCESS,
413 .get = xfs_xattr_acl_get,
414 .set = xfs_xattr_acl_set,
415};
416
417const struct xattr_handler xfs_xattr_acl_default_handler = {
418 .prefix = POSIX_ACL_XATTR_DEFAULT,
419 .flags = ACL_TYPE_DEFAULT,
420 .get = xfs_xattr_acl_get,
421 .set = xfs_xattr_acl_set,
422};