locks: break delegations on any attribute modification
[deliverable/linux.git] / fs / ecryptfs / inode.c
1 /**
2 * eCryptfs: Linux filesystem encryption layer
3 *
4 * Copyright (C) 1997-2004 Erez Zadok
5 * Copyright (C) 2001-2004 Stony Brook University
6 * Copyright (C) 2004-2007 International Business Machines Corp.
7 * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
8 * Michael C. Thompsion <mcthomps@us.ibm.com>
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License as
12 * published by the Free Software Foundation; either version 2 of the
13 * License, or (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
23 * 02111-1307, USA.
24 */
25
26 #include <linux/file.h>
27 #include <linux/vmalloc.h>
28 #include <linux/pagemap.h>
29 #include <linux/dcache.h>
30 #include <linux/namei.h>
31 #include <linux/mount.h>
32 #include <linux/crypto.h>
33 #include <linux/fs_stack.h>
34 #include <linux/slab.h>
35 #include <linux/xattr.h>
36 #include <asm/unaligned.h>
37 #include "ecryptfs_kernel.h"
38
39 static struct dentry *lock_parent(struct dentry *dentry)
40 {
41 struct dentry *dir;
42
43 dir = dget_parent(dentry);
44 mutex_lock_nested(&(dir->d_inode->i_mutex), I_MUTEX_PARENT);
45 return dir;
46 }
47
48 static void unlock_dir(struct dentry *dir)
49 {
50 mutex_unlock(&dir->d_inode->i_mutex);
51 dput(dir);
52 }
53
54 static int ecryptfs_inode_test(struct inode *inode, void *lower_inode)
55 {
56 if (ecryptfs_inode_to_lower(inode) == (struct inode *)lower_inode)
57 return 1;
58 return 0;
59 }
60
61 static int ecryptfs_inode_set(struct inode *inode, void *opaque)
62 {
63 struct inode *lower_inode = opaque;
64
65 ecryptfs_set_inode_lower(inode, lower_inode);
66 fsstack_copy_attr_all(inode, lower_inode);
67 /* i_size will be overwritten for encrypted regular files */
68 fsstack_copy_inode_size(inode, lower_inode);
69 inode->i_ino = lower_inode->i_ino;
70 inode->i_version++;
71 inode->i_mapping->a_ops = &ecryptfs_aops;
72 inode->i_mapping->backing_dev_info = inode->i_sb->s_bdi;
73
74 if (S_ISLNK(inode->i_mode))
75 inode->i_op = &ecryptfs_symlink_iops;
76 else if (S_ISDIR(inode->i_mode))
77 inode->i_op = &ecryptfs_dir_iops;
78 else
79 inode->i_op = &ecryptfs_main_iops;
80
81 if (S_ISDIR(inode->i_mode))
82 inode->i_fop = &ecryptfs_dir_fops;
83 else if (special_file(inode->i_mode))
84 init_special_inode(inode, inode->i_mode, inode->i_rdev);
85 else
86 inode->i_fop = &ecryptfs_main_fops;
87
88 return 0;
89 }
90
91 static struct inode *__ecryptfs_get_inode(struct inode *lower_inode,
92 struct super_block *sb)
93 {
94 struct inode *inode;
95
96 if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb))
97 return ERR_PTR(-EXDEV);
98 if (!igrab(lower_inode))
99 return ERR_PTR(-ESTALE);
100 inode = iget5_locked(sb, (unsigned long)lower_inode,
101 ecryptfs_inode_test, ecryptfs_inode_set,
102 lower_inode);
103 if (!inode) {
104 iput(lower_inode);
105 return ERR_PTR(-EACCES);
106 }
107 if (!(inode->i_state & I_NEW))
108 iput(lower_inode);
109
110 return inode;
111 }
112
113 struct inode *ecryptfs_get_inode(struct inode *lower_inode,
114 struct super_block *sb)
115 {
116 struct inode *inode = __ecryptfs_get_inode(lower_inode, sb);
117
118 if (!IS_ERR(inode) && (inode->i_state & I_NEW))
119 unlock_new_inode(inode);
120
121 return inode;
122 }
123
124 /**
125 * ecryptfs_interpose
126 * @lower_dentry: Existing dentry in the lower filesystem
127 * @dentry: ecryptfs' dentry
128 * @sb: ecryptfs's super_block
129 *
130 * Interposes upper and lower dentries.
131 *
132 * Returns zero on success; non-zero otherwise
133 */
134 static int ecryptfs_interpose(struct dentry *lower_dentry,
135 struct dentry *dentry, struct super_block *sb)
136 {
137 struct inode *inode = ecryptfs_get_inode(lower_dentry->d_inode, sb);
138
139 if (IS_ERR(inode))
140 return PTR_ERR(inode);
141 d_instantiate(dentry, inode);
142
143 return 0;
144 }
145
146 static int ecryptfs_do_unlink(struct inode *dir, struct dentry *dentry,
147 struct inode *inode)
148 {
149 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
150 struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
151 struct dentry *lower_dir_dentry;
152 int rc;
153
154 dget(lower_dentry);
155 lower_dir_dentry = lock_parent(lower_dentry);
156 rc = vfs_unlink(lower_dir_inode, lower_dentry, NULL);
157 if (rc) {
158 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
159 goto out_unlock;
160 }
161 fsstack_copy_attr_times(dir, lower_dir_inode);
162 set_nlink(inode, ecryptfs_inode_to_lower(inode)->i_nlink);
163 inode->i_ctime = dir->i_ctime;
164 d_drop(dentry);
165 out_unlock:
166 unlock_dir(lower_dir_dentry);
167 dput(lower_dentry);
168 return rc;
169 }
170
171 /**
172 * ecryptfs_do_create
173 * @directory_inode: inode of the new file's dentry's parent in ecryptfs
174 * @ecryptfs_dentry: New file's dentry in ecryptfs
175 * @mode: The mode of the new file
176 * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
177 *
178 * Creates the underlying file and the eCryptfs inode which will link to
179 * it. It will also update the eCryptfs directory inode to mimic the
180 * stat of the lower directory inode.
181 *
182 * Returns the new eCryptfs inode on success; an ERR_PTR on error condition
183 */
184 static struct inode *
185 ecryptfs_do_create(struct inode *directory_inode,
186 struct dentry *ecryptfs_dentry, umode_t mode)
187 {
188 int rc;
189 struct dentry *lower_dentry;
190 struct dentry *lower_dir_dentry;
191 struct inode *inode;
192
193 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
194 lower_dir_dentry = lock_parent(lower_dentry);
195 if (IS_ERR(lower_dir_dentry)) {
196 ecryptfs_printk(KERN_ERR, "Error locking directory of "
197 "dentry\n");
198 inode = ERR_CAST(lower_dir_dentry);
199 goto out;
200 }
201 rc = vfs_create(lower_dir_dentry->d_inode, lower_dentry, mode, true);
202 if (rc) {
203 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
204 "rc = [%d]\n", __func__, rc);
205 inode = ERR_PTR(rc);
206 goto out_lock;
207 }
208 inode = __ecryptfs_get_inode(lower_dentry->d_inode,
209 directory_inode->i_sb);
210 if (IS_ERR(inode)) {
211 vfs_unlink(lower_dir_dentry->d_inode, lower_dentry, NULL);
212 goto out_lock;
213 }
214 fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
215 fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode);
216 out_lock:
217 unlock_dir(lower_dir_dentry);
218 out:
219 return inode;
220 }
221
222 /**
223 * ecryptfs_initialize_file
224 *
225 * Cause the file to be changed from a basic empty file to an ecryptfs
226 * file with a header and first data page.
227 *
228 * Returns zero on success
229 */
230 int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry,
231 struct inode *ecryptfs_inode)
232 {
233 struct ecryptfs_crypt_stat *crypt_stat =
234 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
235 int rc = 0;
236
237 if (S_ISDIR(ecryptfs_inode->i_mode)) {
238 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
239 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
240 goto out;
241 }
242 ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
243 rc = ecryptfs_new_file_context(ecryptfs_inode);
244 if (rc) {
245 ecryptfs_printk(KERN_ERR, "Error creating new file "
246 "context; rc = [%d]\n", rc);
247 goto out;
248 }
249 rc = ecryptfs_get_lower_file(ecryptfs_dentry, ecryptfs_inode);
250 if (rc) {
251 printk(KERN_ERR "%s: Error attempting to initialize "
252 "the lower file for the dentry with name "
253 "[%s]; rc = [%d]\n", __func__,
254 ecryptfs_dentry->d_name.name, rc);
255 goto out;
256 }
257 rc = ecryptfs_write_metadata(ecryptfs_dentry, ecryptfs_inode);
258 if (rc)
259 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
260 ecryptfs_put_lower_file(ecryptfs_inode);
261 out:
262 return rc;
263 }
264
265 /**
266 * ecryptfs_create
267 * @dir: The inode of the directory in which to create the file.
268 * @dentry: The eCryptfs dentry
269 * @mode: The mode of the new file.
270 *
271 * Creates a new file.
272 *
273 * Returns zero on success; non-zero on error condition
274 */
275 static int
276 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
277 umode_t mode, bool excl)
278 {
279 struct inode *ecryptfs_inode;
280 int rc;
281
282 ecryptfs_inode = ecryptfs_do_create(directory_inode, ecryptfs_dentry,
283 mode);
284 if (unlikely(IS_ERR(ecryptfs_inode))) {
285 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
286 "lower filesystem\n");
287 rc = PTR_ERR(ecryptfs_inode);
288 goto out;
289 }
290 /* At this point, a file exists on "disk"; we need to make sure
291 * that this on disk file is prepared to be an ecryptfs file */
292 rc = ecryptfs_initialize_file(ecryptfs_dentry, ecryptfs_inode);
293 if (rc) {
294 ecryptfs_do_unlink(directory_inode, ecryptfs_dentry,
295 ecryptfs_inode);
296 make_bad_inode(ecryptfs_inode);
297 unlock_new_inode(ecryptfs_inode);
298 iput(ecryptfs_inode);
299 goto out;
300 }
301 unlock_new_inode(ecryptfs_inode);
302 d_instantiate(ecryptfs_dentry, ecryptfs_inode);
303 out:
304 return rc;
305 }
306
307 static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode)
308 {
309 struct ecryptfs_crypt_stat *crypt_stat;
310 int rc;
311
312 rc = ecryptfs_get_lower_file(dentry, inode);
313 if (rc) {
314 printk(KERN_ERR "%s: Error attempting to initialize "
315 "the lower file for the dentry with name "
316 "[%s]; rc = [%d]\n", __func__,
317 dentry->d_name.name, rc);
318 return rc;
319 }
320
321 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
322 /* TODO: lock for crypt_stat comparison */
323 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
324 ecryptfs_set_default_sizes(crypt_stat);
325
326 rc = ecryptfs_read_and_validate_header_region(inode);
327 ecryptfs_put_lower_file(inode);
328 if (rc) {
329 rc = ecryptfs_read_and_validate_xattr_region(dentry, inode);
330 if (!rc)
331 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
332 }
333
334 /* Must return 0 to allow non-eCryptfs files to be looked up, too */
335 return 0;
336 }
337
338 /**
339 * ecryptfs_lookup_interpose - Dentry interposition for a lookup
340 */
341 static int ecryptfs_lookup_interpose(struct dentry *dentry,
342 struct dentry *lower_dentry,
343 struct inode *dir_inode)
344 {
345 struct inode *inode, *lower_inode = lower_dentry->d_inode;
346 struct ecryptfs_dentry_info *dentry_info;
347 struct vfsmount *lower_mnt;
348 int rc = 0;
349
350 dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
351 if (!dentry_info) {
352 printk(KERN_ERR "%s: Out of memory whilst attempting "
353 "to allocate ecryptfs_dentry_info struct\n",
354 __func__);
355 dput(lower_dentry);
356 return -ENOMEM;
357 }
358
359 lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
360 fsstack_copy_attr_atime(dir_inode, lower_dentry->d_parent->d_inode);
361 BUG_ON(!d_count(lower_dentry));
362
363 ecryptfs_set_dentry_private(dentry, dentry_info);
364 dentry_info->lower_path.mnt = lower_mnt;
365 dentry_info->lower_path.dentry = lower_dentry;
366
367 if (!lower_dentry->d_inode) {
368 /* We want to add because we couldn't find in lower */
369 d_add(dentry, NULL);
370 return 0;
371 }
372 inode = __ecryptfs_get_inode(lower_inode, dir_inode->i_sb);
373 if (IS_ERR(inode)) {
374 printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
375 __func__, PTR_ERR(inode));
376 return PTR_ERR(inode);
377 }
378 if (S_ISREG(inode->i_mode)) {
379 rc = ecryptfs_i_size_read(dentry, inode);
380 if (rc) {
381 make_bad_inode(inode);
382 return rc;
383 }
384 }
385
386 if (inode->i_state & I_NEW)
387 unlock_new_inode(inode);
388 d_add(dentry, inode);
389
390 return rc;
391 }
392
393 /**
394 * ecryptfs_lookup
395 * @ecryptfs_dir_inode: The eCryptfs directory inode
396 * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
397 * @ecryptfs_nd: nameidata; may be NULL
398 *
399 * Find a file on disk. If the file does not exist, then we'll add it to the
400 * dentry cache and continue on to read it from the disk.
401 */
402 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
403 struct dentry *ecryptfs_dentry,
404 unsigned int flags)
405 {
406 char *encrypted_and_encoded_name = NULL;
407 size_t encrypted_and_encoded_name_size;
408 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
409 struct dentry *lower_dir_dentry, *lower_dentry;
410 int rc = 0;
411
412 lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
413 mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
414 lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name,
415 lower_dir_dentry,
416 ecryptfs_dentry->d_name.len);
417 mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
418 if (IS_ERR(lower_dentry)) {
419 rc = PTR_ERR(lower_dentry);
420 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
421 "[%d] on lower_dentry = [%s]\n", __func__, rc,
422 ecryptfs_dentry->d_name.name);
423 goto out;
424 }
425 if (lower_dentry->d_inode)
426 goto interpose;
427 mount_crypt_stat = &ecryptfs_superblock_to_private(
428 ecryptfs_dentry->d_sb)->mount_crypt_stat;
429 if (!(mount_crypt_stat
430 && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)))
431 goto interpose;
432 dput(lower_dentry);
433 rc = ecryptfs_encrypt_and_encode_filename(
434 &encrypted_and_encoded_name, &encrypted_and_encoded_name_size,
435 NULL, mount_crypt_stat, ecryptfs_dentry->d_name.name,
436 ecryptfs_dentry->d_name.len);
437 if (rc) {
438 printk(KERN_ERR "%s: Error attempting to encrypt and encode "
439 "filename; rc = [%d]\n", __func__, rc);
440 goto out;
441 }
442 mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
443 lower_dentry = lookup_one_len(encrypted_and_encoded_name,
444 lower_dir_dentry,
445 encrypted_and_encoded_name_size);
446 mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
447 if (IS_ERR(lower_dentry)) {
448 rc = PTR_ERR(lower_dentry);
449 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
450 "[%d] on lower_dentry = [%s]\n", __func__, rc,
451 encrypted_and_encoded_name);
452 goto out;
453 }
454 interpose:
455 rc = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry,
456 ecryptfs_dir_inode);
457 out:
458 kfree(encrypted_and_encoded_name);
459 return ERR_PTR(rc);
460 }
461
462 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
463 struct dentry *new_dentry)
464 {
465 struct dentry *lower_old_dentry;
466 struct dentry *lower_new_dentry;
467 struct dentry *lower_dir_dentry;
468 u64 file_size_save;
469 int rc;
470
471 file_size_save = i_size_read(old_dentry->d_inode);
472 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
473 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
474 dget(lower_old_dentry);
475 dget(lower_new_dentry);
476 lower_dir_dentry = lock_parent(lower_new_dentry);
477 rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
478 lower_new_dentry, NULL);
479 if (rc || !lower_new_dentry->d_inode)
480 goto out_lock;
481 rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
482 if (rc)
483 goto out_lock;
484 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
485 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
486 set_nlink(old_dentry->d_inode,
487 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink);
488 i_size_write(new_dentry->d_inode, file_size_save);
489 out_lock:
490 unlock_dir(lower_dir_dentry);
491 dput(lower_new_dentry);
492 dput(lower_old_dentry);
493 return rc;
494 }
495
496 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
497 {
498 return ecryptfs_do_unlink(dir, dentry, dentry->d_inode);
499 }
500
501 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
502 const char *symname)
503 {
504 int rc;
505 struct dentry *lower_dentry;
506 struct dentry *lower_dir_dentry;
507 char *encoded_symname;
508 size_t encoded_symlen;
509 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
510
511 lower_dentry = ecryptfs_dentry_to_lower(dentry);
512 dget(lower_dentry);
513 lower_dir_dentry = lock_parent(lower_dentry);
514 mount_crypt_stat = &ecryptfs_superblock_to_private(
515 dir->i_sb)->mount_crypt_stat;
516 rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
517 &encoded_symlen,
518 NULL,
519 mount_crypt_stat, symname,
520 strlen(symname));
521 if (rc)
522 goto out_lock;
523 rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
524 encoded_symname);
525 kfree(encoded_symname);
526 if (rc || !lower_dentry->d_inode)
527 goto out_lock;
528 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
529 if (rc)
530 goto out_lock;
531 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
532 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
533 out_lock:
534 unlock_dir(lower_dir_dentry);
535 dput(lower_dentry);
536 if (!dentry->d_inode)
537 d_drop(dentry);
538 return rc;
539 }
540
541 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
542 {
543 int rc;
544 struct dentry *lower_dentry;
545 struct dentry *lower_dir_dentry;
546
547 lower_dentry = ecryptfs_dentry_to_lower(dentry);
548 lower_dir_dentry = lock_parent(lower_dentry);
549 rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
550 if (rc || !lower_dentry->d_inode)
551 goto out;
552 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
553 if (rc)
554 goto out;
555 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
556 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
557 set_nlink(dir, lower_dir_dentry->d_inode->i_nlink);
558 out:
559 unlock_dir(lower_dir_dentry);
560 if (!dentry->d_inode)
561 d_drop(dentry);
562 return rc;
563 }
564
565 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
566 {
567 struct dentry *lower_dentry;
568 struct dentry *lower_dir_dentry;
569 int rc;
570
571 lower_dentry = ecryptfs_dentry_to_lower(dentry);
572 dget(dentry);
573 lower_dir_dentry = lock_parent(lower_dentry);
574 dget(lower_dentry);
575 rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
576 dput(lower_dentry);
577 if (!rc && dentry->d_inode)
578 clear_nlink(dentry->d_inode);
579 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
580 set_nlink(dir, lower_dir_dentry->d_inode->i_nlink);
581 unlock_dir(lower_dir_dentry);
582 if (!rc)
583 d_drop(dentry);
584 dput(dentry);
585 return rc;
586 }
587
588 static int
589 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
590 {
591 int rc;
592 struct dentry *lower_dentry;
593 struct dentry *lower_dir_dentry;
594
595 lower_dentry = ecryptfs_dentry_to_lower(dentry);
596 lower_dir_dentry = lock_parent(lower_dentry);
597 rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
598 if (rc || !lower_dentry->d_inode)
599 goto out;
600 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
601 if (rc)
602 goto out;
603 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
604 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
605 out:
606 unlock_dir(lower_dir_dentry);
607 if (!dentry->d_inode)
608 d_drop(dentry);
609 return rc;
610 }
611
612 static int
613 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
614 struct inode *new_dir, struct dentry *new_dentry)
615 {
616 int rc;
617 struct dentry *lower_old_dentry;
618 struct dentry *lower_new_dentry;
619 struct dentry *lower_old_dir_dentry;
620 struct dentry *lower_new_dir_dentry;
621 struct dentry *trap = NULL;
622 struct inode *target_inode;
623
624 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
625 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
626 dget(lower_old_dentry);
627 dget(lower_new_dentry);
628 lower_old_dir_dentry = dget_parent(lower_old_dentry);
629 lower_new_dir_dentry = dget_parent(lower_new_dentry);
630 target_inode = new_dentry->d_inode;
631 trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
632 /* source should not be ancestor of target */
633 if (trap == lower_old_dentry) {
634 rc = -EINVAL;
635 goto out_lock;
636 }
637 /* target should not be ancestor of source */
638 if (trap == lower_new_dentry) {
639 rc = -ENOTEMPTY;
640 goto out_lock;
641 }
642 rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
643 lower_new_dir_dentry->d_inode, lower_new_dentry,
644 NULL);
645 if (rc)
646 goto out_lock;
647 if (target_inode)
648 fsstack_copy_attr_all(target_inode,
649 ecryptfs_inode_to_lower(target_inode));
650 fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode);
651 if (new_dir != old_dir)
652 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode);
653 out_lock:
654 unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
655 dput(lower_new_dir_dentry);
656 dput(lower_old_dir_dentry);
657 dput(lower_new_dentry);
658 dput(lower_old_dentry);
659 return rc;
660 }
661
662 static int ecryptfs_readlink_lower(struct dentry *dentry, char **buf,
663 size_t *bufsiz)
664 {
665 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
666 char *lower_buf;
667 mm_segment_t old_fs;
668 int rc;
669
670 lower_buf = kmalloc(PATH_MAX, GFP_KERNEL);
671 if (!lower_buf) {
672 rc = -ENOMEM;
673 goto out;
674 }
675 old_fs = get_fs();
676 set_fs(get_ds());
677 rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
678 (char __user *)lower_buf,
679 PATH_MAX);
680 set_fs(old_fs);
681 if (rc < 0)
682 goto out;
683 rc = ecryptfs_decode_and_decrypt_filename(buf, bufsiz, dentry->d_sb,
684 lower_buf, rc);
685 out:
686 kfree(lower_buf);
687 return rc;
688 }
689
690 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
691 {
692 char *buf;
693 size_t len = PATH_MAX;
694 int rc;
695
696 rc = ecryptfs_readlink_lower(dentry, &buf, &len);
697 if (rc)
698 goto out;
699 fsstack_copy_attr_atime(dentry->d_inode,
700 ecryptfs_dentry_to_lower(dentry)->d_inode);
701 buf[len] = '\0';
702 out:
703 nd_set_link(nd, buf);
704 return NULL;
705 }
706
707 /**
708 * upper_size_to_lower_size
709 * @crypt_stat: Crypt_stat associated with file
710 * @upper_size: Size of the upper file
711 *
712 * Calculate the required size of the lower file based on the
713 * specified size of the upper file. This calculation is based on the
714 * number of headers in the underlying file and the extent size.
715 *
716 * Returns Calculated size of the lower file.
717 */
718 static loff_t
719 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
720 loff_t upper_size)
721 {
722 loff_t lower_size;
723
724 lower_size = ecryptfs_lower_header_size(crypt_stat);
725 if (upper_size != 0) {
726 loff_t num_extents;
727
728 num_extents = upper_size >> crypt_stat->extent_shift;
729 if (upper_size & ~crypt_stat->extent_mask)
730 num_extents++;
731 lower_size += (num_extents * crypt_stat->extent_size);
732 }
733 return lower_size;
734 }
735
736 /**
737 * truncate_upper
738 * @dentry: The ecryptfs layer dentry
739 * @ia: Address of the ecryptfs inode's attributes
740 * @lower_ia: Address of the lower inode's attributes
741 *
742 * Function to handle truncations modifying the size of the file. Note
743 * that the file sizes are interpolated. When expanding, we are simply
744 * writing strings of 0's out. When truncating, we truncate the upper
745 * inode and update the lower_ia according to the page index
746 * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
747 * the caller must use lower_ia in a call to notify_change() to perform
748 * the truncation of the lower inode.
749 *
750 * Returns zero on success; non-zero otherwise
751 */
752 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
753 struct iattr *lower_ia)
754 {
755 int rc = 0;
756 struct inode *inode = dentry->d_inode;
757 struct ecryptfs_crypt_stat *crypt_stat;
758 loff_t i_size = i_size_read(inode);
759 loff_t lower_size_before_truncate;
760 loff_t lower_size_after_truncate;
761
762 if (unlikely((ia->ia_size == i_size))) {
763 lower_ia->ia_valid &= ~ATTR_SIZE;
764 return 0;
765 }
766 rc = ecryptfs_get_lower_file(dentry, inode);
767 if (rc)
768 return rc;
769 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
770 /* Switch on growing or shrinking file */
771 if (ia->ia_size > i_size) {
772 char zero[] = { 0x00 };
773
774 lower_ia->ia_valid &= ~ATTR_SIZE;
775 /* Write a single 0 at the last position of the file;
776 * this triggers code that will fill in 0's throughout
777 * the intermediate portion of the previous end of the
778 * file and the new and of the file */
779 rc = ecryptfs_write(inode, zero,
780 (ia->ia_size - 1), 1);
781 } else { /* ia->ia_size < i_size_read(inode) */
782 /* We're chopping off all the pages down to the page
783 * in which ia->ia_size is located. Fill in the end of
784 * that page from (ia->ia_size & ~PAGE_CACHE_MASK) to
785 * PAGE_CACHE_SIZE with zeros. */
786 size_t num_zeros = (PAGE_CACHE_SIZE
787 - (ia->ia_size & ~PAGE_CACHE_MASK));
788
789 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
790 truncate_setsize(inode, ia->ia_size);
791 lower_ia->ia_size = ia->ia_size;
792 lower_ia->ia_valid |= ATTR_SIZE;
793 goto out;
794 }
795 if (num_zeros) {
796 char *zeros_virt;
797
798 zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
799 if (!zeros_virt) {
800 rc = -ENOMEM;
801 goto out;
802 }
803 rc = ecryptfs_write(inode, zeros_virt,
804 ia->ia_size, num_zeros);
805 kfree(zeros_virt);
806 if (rc) {
807 printk(KERN_ERR "Error attempting to zero out "
808 "the remainder of the end page on "
809 "reducing truncate; rc = [%d]\n", rc);
810 goto out;
811 }
812 }
813 truncate_setsize(inode, ia->ia_size);
814 rc = ecryptfs_write_inode_size_to_metadata(inode);
815 if (rc) {
816 printk(KERN_ERR "Problem with "
817 "ecryptfs_write_inode_size_to_metadata; "
818 "rc = [%d]\n", rc);
819 goto out;
820 }
821 /* We are reducing the size of the ecryptfs file, and need to
822 * know if we need to reduce the size of the lower file. */
823 lower_size_before_truncate =
824 upper_size_to_lower_size(crypt_stat, i_size);
825 lower_size_after_truncate =
826 upper_size_to_lower_size(crypt_stat, ia->ia_size);
827 if (lower_size_after_truncate < lower_size_before_truncate) {
828 lower_ia->ia_size = lower_size_after_truncate;
829 lower_ia->ia_valid |= ATTR_SIZE;
830 } else
831 lower_ia->ia_valid &= ~ATTR_SIZE;
832 }
833 out:
834 ecryptfs_put_lower_file(inode);
835 return rc;
836 }
837
838 static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset)
839 {
840 struct ecryptfs_crypt_stat *crypt_stat;
841 loff_t lower_oldsize, lower_newsize;
842
843 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
844 lower_oldsize = upper_size_to_lower_size(crypt_stat,
845 i_size_read(inode));
846 lower_newsize = upper_size_to_lower_size(crypt_stat, offset);
847 if (lower_newsize > lower_oldsize) {
848 /*
849 * The eCryptfs inode and the new *lower* size are mixed here
850 * because we may not have the lower i_mutex held and/or it may
851 * not be appropriate to call inode_newsize_ok() with inodes
852 * from other filesystems.
853 */
854 return inode_newsize_ok(inode, lower_newsize);
855 }
856
857 return 0;
858 }
859
860 /**
861 * ecryptfs_truncate
862 * @dentry: The ecryptfs layer dentry
863 * @new_length: The length to expand the file to
864 *
865 * Simple function that handles the truncation of an eCryptfs inode and
866 * its corresponding lower inode.
867 *
868 * Returns zero on success; non-zero otherwise
869 */
870 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
871 {
872 struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
873 struct iattr lower_ia = { .ia_valid = 0 };
874 int rc;
875
876 rc = ecryptfs_inode_newsize_ok(dentry->d_inode, new_length);
877 if (rc)
878 return rc;
879
880 rc = truncate_upper(dentry, &ia, &lower_ia);
881 if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
882 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
883
884 mutex_lock(&lower_dentry->d_inode->i_mutex);
885 rc = notify_change(lower_dentry, &lower_ia, NULL);
886 mutex_unlock(&lower_dentry->d_inode->i_mutex);
887 }
888 return rc;
889 }
890
891 static int
892 ecryptfs_permission(struct inode *inode, int mask)
893 {
894 return inode_permission(ecryptfs_inode_to_lower(inode), mask);
895 }
896
897 /**
898 * ecryptfs_setattr
899 * @dentry: dentry handle to the inode to modify
900 * @ia: Structure with flags of what to change and values
901 *
902 * Updates the metadata of an inode. If the update is to the size
903 * i.e. truncation, then ecryptfs_truncate will handle the size modification
904 * of both the ecryptfs inode and the lower inode.
905 *
906 * All other metadata changes will be passed right to the lower filesystem,
907 * and we will just update our inode to look like the lower.
908 */
909 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
910 {
911 int rc = 0;
912 struct dentry *lower_dentry;
913 struct iattr lower_ia;
914 struct inode *inode;
915 struct inode *lower_inode;
916 struct ecryptfs_crypt_stat *crypt_stat;
917
918 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
919 if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
920 ecryptfs_init_crypt_stat(crypt_stat);
921 inode = dentry->d_inode;
922 lower_inode = ecryptfs_inode_to_lower(inode);
923 lower_dentry = ecryptfs_dentry_to_lower(dentry);
924 mutex_lock(&crypt_stat->cs_mutex);
925 if (S_ISDIR(dentry->d_inode->i_mode))
926 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
927 else if (S_ISREG(dentry->d_inode->i_mode)
928 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
929 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
930 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
931
932 mount_crypt_stat = &ecryptfs_superblock_to_private(
933 dentry->d_sb)->mount_crypt_stat;
934 rc = ecryptfs_get_lower_file(dentry, inode);
935 if (rc) {
936 mutex_unlock(&crypt_stat->cs_mutex);
937 goto out;
938 }
939 rc = ecryptfs_read_metadata(dentry);
940 ecryptfs_put_lower_file(inode);
941 if (rc) {
942 if (!(mount_crypt_stat->flags
943 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
944 rc = -EIO;
945 printk(KERN_WARNING "Either the lower file "
946 "is not in a valid eCryptfs format, "
947 "or the key could not be retrieved. "
948 "Plaintext passthrough mode is not "
949 "enabled; returning -EIO\n");
950 mutex_unlock(&crypt_stat->cs_mutex);
951 goto out;
952 }
953 rc = 0;
954 crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
955 | ECRYPTFS_ENCRYPTED);
956 }
957 }
958 mutex_unlock(&crypt_stat->cs_mutex);
959
960 rc = inode_change_ok(inode, ia);
961 if (rc)
962 goto out;
963 if (ia->ia_valid & ATTR_SIZE) {
964 rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size);
965 if (rc)
966 goto out;
967 }
968
969 memcpy(&lower_ia, ia, sizeof(lower_ia));
970 if (ia->ia_valid & ATTR_FILE)
971 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
972 if (ia->ia_valid & ATTR_SIZE) {
973 rc = truncate_upper(dentry, ia, &lower_ia);
974 if (rc < 0)
975 goto out;
976 }
977
978 /*
979 * mode change is for clearing setuid/setgid bits. Allow lower fs
980 * to interpret this in its own way.
981 */
982 if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
983 lower_ia.ia_valid &= ~ATTR_MODE;
984
985 mutex_lock(&lower_dentry->d_inode->i_mutex);
986 rc = notify_change(lower_dentry, &lower_ia, NULL);
987 mutex_unlock(&lower_dentry->d_inode->i_mutex);
988 out:
989 fsstack_copy_attr_all(inode, lower_inode);
990 return rc;
991 }
992
993 static int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
994 struct kstat *stat)
995 {
996 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
997 int rc = 0;
998
999 mount_crypt_stat = &ecryptfs_superblock_to_private(
1000 dentry->d_sb)->mount_crypt_stat;
1001 generic_fillattr(dentry->d_inode, stat);
1002 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
1003 char *target;
1004 size_t targetsiz;
1005
1006 rc = ecryptfs_readlink_lower(dentry, &target, &targetsiz);
1007 if (!rc) {
1008 kfree(target);
1009 stat->size = targetsiz;
1010 }
1011 }
1012 return rc;
1013 }
1014
1015 static int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
1016 struct kstat *stat)
1017 {
1018 struct kstat lower_stat;
1019 int rc;
1020
1021 rc = vfs_getattr(ecryptfs_dentry_to_lower_path(dentry), &lower_stat);
1022 if (!rc) {
1023 fsstack_copy_attr_all(dentry->d_inode,
1024 ecryptfs_inode_to_lower(dentry->d_inode));
1025 generic_fillattr(dentry->d_inode, stat);
1026 stat->blocks = lower_stat.blocks;
1027 }
1028 return rc;
1029 }
1030
1031 int
1032 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
1033 size_t size, int flags)
1034 {
1035 int rc = 0;
1036 struct dentry *lower_dentry;
1037
1038 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1039 if (!lower_dentry->d_inode->i_op->setxattr) {
1040 rc = -EOPNOTSUPP;
1041 goto out;
1042 }
1043
1044 rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1045 if (!rc)
1046 fsstack_copy_attr_all(dentry->d_inode, lower_dentry->d_inode);
1047 out:
1048 return rc;
1049 }
1050
1051 ssize_t
1052 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
1053 void *value, size_t size)
1054 {
1055 int rc = 0;
1056
1057 if (!lower_dentry->d_inode->i_op->getxattr) {
1058 rc = -EOPNOTSUPP;
1059 goto out;
1060 }
1061 mutex_lock(&lower_dentry->d_inode->i_mutex);
1062 rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
1063 size);
1064 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1065 out:
1066 return rc;
1067 }
1068
1069 static ssize_t
1070 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
1071 size_t size)
1072 {
1073 return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
1074 value, size);
1075 }
1076
1077 static ssize_t
1078 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1079 {
1080 int rc = 0;
1081 struct dentry *lower_dentry;
1082
1083 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1084 if (!lower_dentry->d_inode->i_op->listxattr) {
1085 rc = -EOPNOTSUPP;
1086 goto out;
1087 }
1088 mutex_lock(&lower_dentry->d_inode->i_mutex);
1089 rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1090 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1091 out:
1092 return rc;
1093 }
1094
1095 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1096 {
1097 int rc = 0;
1098 struct dentry *lower_dentry;
1099
1100 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1101 if (!lower_dentry->d_inode->i_op->removexattr) {
1102 rc = -EOPNOTSUPP;
1103 goto out;
1104 }
1105 mutex_lock(&lower_dentry->d_inode->i_mutex);
1106 rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1107 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1108 out:
1109 return rc;
1110 }
1111
1112 const struct inode_operations ecryptfs_symlink_iops = {
1113 .readlink = generic_readlink,
1114 .follow_link = ecryptfs_follow_link,
1115 .put_link = kfree_put_link,
1116 .permission = ecryptfs_permission,
1117 .setattr = ecryptfs_setattr,
1118 .getattr = ecryptfs_getattr_link,
1119 .setxattr = ecryptfs_setxattr,
1120 .getxattr = ecryptfs_getxattr,
1121 .listxattr = ecryptfs_listxattr,
1122 .removexattr = ecryptfs_removexattr
1123 };
1124
1125 const struct inode_operations ecryptfs_dir_iops = {
1126 .create = ecryptfs_create,
1127 .lookup = ecryptfs_lookup,
1128 .link = ecryptfs_link,
1129 .unlink = ecryptfs_unlink,
1130 .symlink = ecryptfs_symlink,
1131 .mkdir = ecryptfs_mkdir,
1132 .rmdir = ecryptfs_rmdir,
1133 .mknod = ecryptfs_mknod,
1134 .rename = ecryptfs_rename,
1135 .permission = ecryptfs_permission,
1136 .setattr = ecryptfs_setattr,
1137 .setxattr = ecryptfs_setxattr,
1138 .getxattr = ecryptfs_getxattr,
1139 .listxattr = ecryptfs_listxattr,
1140 .removexattr = ecryptfs_removexattr
1141 };
1142
1143 const struct inode_operations ecryptfs_main_iops = {
1144 .permission = ecryptfs_permission,
1145 .setattr = ecryptfs_setattr,
1146 .getattr = ecryptfs_getattr,
1147 .setxattr = ecryptfs_setxattr,
1148 .getxattr = ecryptfs_getxattr,
1149 .listxattr = ecryptfs_listxattr,
1150 .removexattr = ecryptfs_removexattr
1151 };
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