1// SPDX-License-Identifier: GPL-2.0
2#include <linux/capability.h>
3#include <linux/fs.h>
4#include <linux/posix_acl.h>
5#include "reiserfs.h"
6#include <linux/errno.h>
7#include <linux/pagemap.h>
8#include <linux/xattr.h>
9#include <linux/slab.h>
10#include <linux/posix_acl_xattr.h>
11#include "xattr.h"
12#include "acl.h"
13#include <linux/uaccess.h>
14
15static int __reiserfs_set_acl(struct reiserfs_transaction_handle *th,
16 struct inode *inode, int type,
17 struct posix_acl *acl);
18
19
20int
21reiserfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
22 struct posix_acl *acl, int type)
23{
24 int error, error2;
25 struct reiserfs_transaction_handle th;
26 size_t jcreate_blocks;
27 int size = acl ? posix_acl_xattr_size(count: acl->a_count) : 0;
28 int update_mode = 0;
29 struct inode *inode = d_inode(dentry);
30 umode_t mode = inode->i_mode;
31
32 /*
33 * Pessimism: We can't assume that anything from the xattr root up
34 * has been created.
35 */
36
37 jcreate_blocks = reiserfs_xattr_jcreate_nblocks(inode) +
38 reiserfs_xattr_nblocks(inode, size) * 2;
39
40 reiserfs_write_lock(s: inode->i_sb);
41 error = journal_begin(&th, sb: inode->i_sb, jcreate_blocks);
42 reiserfs_write_unlock(s: inode->i_sb);
43 if (error == 0) {
44 if (type == ACL_TYPE_ACCESS && acl) {
45 error = posix_acl_update_mode(&nop_mnt_idmap, inode,
46 &mode, &acl);
47 if (error)
48 goto unlock;
49 update_mode = 1;
50 }
51 error = __reiserfs_set_acl(th: &th, inode, type, acl);
52 if (!error && update_mode)
53 inode->i_mode = mode;
54unlock:
55 reiserfs_write_lock(s: inode->i_sb);
56 error2 = journal_end(&th);
57 reiserfs_write_unlock(s: inode->i_sb);
58 if (error2)
59 error = error2;
60 }
61
62 return error;
63}
64
65/*
66 * Convert from filesystem to in-memory representation.
67 */
68static struct posix_acl *reiserfs_posix_acl_from_disk(const void *value, size_t size)
69{
70 const char *end = (char *)value + size;
71 int n, count;
72 struct posix_acl *acl;
73
74 if (!value)
75 return NULL;
76 if (size < sizeof(reiserfs_acl_header))
77 return ERR_PTR(error: -EINVAL);
78 if (((reiserfs_acl_header *) value)->a_version !=
79 cpu_to_le32(REISERFS_ACL_VERSION))
80 return ERR_PTR(error: -EINVAL);
81 value = (char *)value + sizeof(reiserfs_acl_header);
82 count = reiserfs_acl_count(size);
83 if (count < 0)
84 return ERR_PTR(error: -EINVAL);
85 if (count == 0)
86 return NULL;
87 acl = posix_acl_alloc(count, GFP_NOFS);
88 if (!acl)
89 return ERR_PTR(error: -ENOMEM);
90 for (n = 0; n < count; n++) {
91 reiserfs_acl_entry *entry = (reiserfs_acl_entry *) value;
92 if ((char *)value + sizeof(reiserfs_acl_entry_short) > end)
93 goto fail;
94 acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
95 acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
96 switch (acl->a_entries[n].e_tag) {
97 case ACL_USER_OBJ:
98 case ACL_GROUP_OBJ:
99 case ACL_MASK:
100 case ACL_OTHER:
101 value = (char *)value +
102 sizeof(reiserfs_acl_entry_short);
103 break;
104
105 case ACL_USER:
106 value = (char *)value + sizeof(reiserfs_acl_entry);
107 if ((char *)value > end)
108 goto fail;
109 acl->a_entries[n].e_uid =
110 make_kuid(from: &init_user_ns,
111 le32_to_cpu(entry->e_id));
112 break;
113 case ACL_GROUP:
114 value = (char *)value + sizeof(reiserfs_acl_entry);
115 if ((char *)value > end)
116 goto fail;
117 acl->a_entries[n].e_gid =
118 make_kgid(from: &init_user_ns,
119 le32_to_cpu(entry->e_id));
120 break;
121
122 default:
123 goto fail;
124 }
125 }
126 if (value != end)
127 goto fail;
128 return acl;
129
130fail:
131 posix_acl_release(acl);
132 return ERR_PTR(error: -EINVAL);
133}
134
135/*
136 * Convert from in-memory to filesystem representation.
137 */
138static void *reiserfs_posix_acl_to_disk(const struct posix_acl *acl, size_t * size)
139{
140 reiserfs_acl_header *ext_acl;
141 char *e;
142 int n;
143
144 *size = reiserfs_acl_size(count: acl->a_count);
145 ext_acl = kmalloc(size: sizeof(reiserfs_acl_header) +
146 acl->a_count *
147 sizeof(reiserfs_acl_entry),
148 GFP_NOFS);
149 if (!ext_acl)
150 return ERR_PTR(error: -ENOMEM);
151 ext_acl->a_version = cpu_to_le32(REISERFS_ACL_VERSION);
152 e = (char *)ext_acl + sizeof(reiserfs_acl_header);
153 for (n = 0; n < acl->a_count; n++) {
154 const struct posix_acl_entry *acl_e = &acl->a_entries[n];
155 reiserfs_acl_entry *entry = (reiserfs_acl_entry *) e;
156 entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
157 entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
158 switch (acl->a_entries[n].e_tag) {
159 case ACL_USER:
160 entry->e_id = cpu_to_le32(
161 from_kuid(&init_user_ns, acl_e->e_uid));
162 e += sizeof(reiserfs_acl_entry);
163 break;
164 case ACL_GROUP:
165 entry->e_id = cpu_to_le32(
166 from_kgid(&init_user_ns, acl_e->e_gid));
167 e += sizeof(reiserfs_acl_entry);
168 break;
169
170 case ACL_USER_OBJ:
171 case ACL_GROUP_OBJ:
172 case ACL_MASK:
173 case ACL_OTHER:
174 e += sizeof(reiserfs_acl_entry_short);
175 break;
176
177 default:
178 goto fail;
179 }
180 }
181 return (char *)ext_acl;
182
183fail:
184 kfree(objp: ext_acl);
185 return ERR_PTR(error: -EINVAL);
186}
187
188/*
189 * Inode operation get_posix_acl().
190 *
191 * inode->i_mutex: down
192 * BKL held [before 2.5.x]
193 */
194struct posix_acl *reiserfs_get_acl(struct inode *inode, int type, bool rcu)
195{
196 char *name, *value;
197 struct posix_acl *acl;
198 int size;
199 int retval;
200
201 if (rcu)
202 return ERR_PTR(error: -ECHILD);
203
204 switch (type) {
205 case ACL_TYPE_ACCESS:
206 name = XATTR_NAME_POSIX_ACL_ACCESS;
207 break;
208 case ACL_TYPE_DEFAULT:
209 name = XATTR_NAME_POSIX_ACL_DEFAULT;
210 break;
211 default:
212 BUG();
213 }
214
215 size = reiserfs_xattr_get(inode, name, NULL, 0);
216 if (size < 0) {
217 if (size == -ENODATA || size == -ENOSYS)
218 return NULL;
219 return ERR_PTR(error: size);
220 }
221
222 value = kmalloc(size, GFP_NOFS);
223 if (!value)
224 return ERR_PTR(error: -ENOMEM);
225
226 retval = reiserfs_xattr_get(inode, name, value, size);
227 if (retval == -ENODATA || retval == -ENOSYS) {
228 /*
229 * This shouldn't actually happen as it should have
230 * been caught above.. but just in case
231 */
232 acl = NULL;
233 } else if (retval < 0) {
234 acl = ERR_PTR(error: retval);
235 } else {
236 acl = reiserfs_posix_acl_from_disk(value, size: retval);
237 }
238
239 kfree(objp: value);
240 return acl;
241}
242
243/*
244 * Inode operation set_posix_acl().
245 *
246 * inode->i_mutex: down
247 * BKL held [before 2.5.x]
248 */
249static int
250__reiserfs_set_acl(struct reiserfs_transaction_handle *th, struct inode *inode,
251 int type, struct posix_acl *acl)
252{
253 char *name;
254 void *value = NULL;
255 size_t size = 0;
256 int error;
257
258 switch (type) {
259 case ACL_TYPE_ACCESS:
260 name = XATTR_NAME_POSIX_ACL_ACCESS;
261 break;
262 case ACL_TYPE_DEFAULT:
263 name = XATTR_NAME_POSIX_ACL_DEFAULT;
264 if (!S_ISDIR(inode->i_mode))
265 return acl ? -EACCES : 0;
266 break;
267 default:
268 return -EINVAL;
269 }
270
271 if (acl) {
272 value = reiserfs_posix_acl_to_disk(acl, size: &size);
273 if (IS_ERR(ptr: value))
274 return (int)PTR_ERR(ptr: value);
275 }
276
277 error = reiserfs_xattr_set_handle(th, inode, name, value, size, 0);
278
279 /*
280 * Ensure that the inode gets dirtied if we're only using
281 * the mode bits and an old ACL didn't exist. We don't need
282 * to check if the inode is hashed here since we won't get
283 * called by reiserfs_inherit_default_acl().
284 */
285 if (error == -ENODATA) {
286 error = 0;
287 if (type == ACL_TYPE_ACCESS) {
288 inode_set_ctime_current(inode);
289 mark_inode_dirty(inode);
290 }
291 }
292
293 kfree(objp: value);
294
295 if (!error)
296 set_cached_acl(inode, type, acl);
297
298 return error;
299}
300
301/*
302 * dir->i_mutex: locked,
303 * inode is new and not released into the wild yet
304 */
305int
306reiserfs_inherit_default_acl(struct reiserfs_transaction_handle *th,
307 struct inode *dir, struct dentry *dentry,
308 struct inode *inode)
309{
310 struct posix_acl *default_acl, *acl;
311 int err = 0;
312
313 /* ACLs only get applied to files and directories */
314 if (S_ISLNK(inode->i_mode))
315 return 0;
316
317 /*
318 * ACLs can only be used on "new" objects, so if it's an old object
319 * there is nothing to inherit from
320 */
321 if (get_inode_sd_version(dir) == STAT_DATA_V1)
322 goto apply_umask;
323
324 /*
325 * Don't apply ACLs to objects in the .reiserfs_priv tree.. This
326 * would be useless since permissions are ignored, and a pain because
327 * it introduces locking cycles
328 */
329 if (IS_PRIVATE(inode))
330 goto apply_umask;
331
332 err = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
333 if (err)
334 return err;
335
336 if (default_acl) {
337 err = __reiserfs_set_acl(th, inode, ACL_TYPE_DEFAULT,
338 acl: default_acl);
339 posix_acl_release(acl: default_acl);
340 }
341 if (acl) {
342 if (!err)
343 err = __reiserfs_set_acl(th, inode, ACL_TYPE_ACCESS,
344 acl);
345 posix_acl_release(acl);
346 }
347
348 return err;
349
350apply_umask:
351 /* no ACL, apply umask */
352 inode->i_mode &= ~current_umask();
353 return err;
354}
355
356/* This is used to cache the default acl before a new object is created.
357 * The biggest reason for this is to get an idea of how many blocks will
358 * actually be required for the create operation if we must inherit an ACL.
359 * An ACL write can add up to 3 object creations and an additional file write
360 * so we'd prefer not to reserve that many blocks in the journal if we can.
361 * It also has the advantage of not loading the ACL with a transaction open,
362 * this may seem silly, but if the owner of the directory is doing the
363 * creation, the ACL may not be loaded since the permissions wouldn't require
364 * it.
365 * We return the number of blocks required for the transaction.
366 */
367int reiserfs_cache_default_acl(struct inode *inode)
368{
369 struct posix_acl *acl;
370 int nblocks = 0;
371
372 if (IS_PRIVATE(inode))
373 return 0;
374
375 acl = get_inode_acl(inode, ACL_TYPE_DEFAULT);
376
377 if (acl && !IS_ERR(ptr: acl)) {
378 int size = reiserfs_acl_size(count: acl->a_count);
379
380 /* Other xattrs can be created during inode creation. We don't
381 * want to claim too many blocks, so we check to see if we
382 * need to create the tree to the xattrs, and then we
383 * just want two files. */
384 nblocks = reiserfs_xattr_jcreate_nblocks(inode);
385 nblocks += JOURNAL_BLOCKS_PER_OBJECT(inode->i_sb);
386
387 REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
388
389 /* We need to account for writes + bitmaps for two files */
390 nblocks += reiserfs_xattr_nblocks(inode, size) * 4;
391 posix_acl_release(acl);
392 }
393
394 return nblocks;
395}
396
397/*
398 * Called under i_mutex
399 */
400int reiserfs_acl_chmod(struct dentry *dentry)
401{
402 struct inode *inode = d_inode(dentry);
403
404 if (IS_PRIVATE(inode))
405 return 0;
406 if (get_inode_sd_version(inode) == STAT_DATA_V1 ||
407 !reiserfs_posixacl(inode->i_sb))
408 return 0;
409
410 return posix_acl_chmod(&nop_mnt_idmap, dentry, inode->i_mode);
411}
412

source code of linux/fs/reiserfs/xattr_acl.c