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