time: Fix timeekeping_get_ns overflow on 32bit systems
[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);
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);
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(!lower_dentry->d_count);
362
363 ecryptfs_set_dentry_private(dentry, dentry_info);
364 ecryptfs_set_dentry_lower(dentry, lower_dentry);
365 ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
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);
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
623 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
624 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
625 dget(lower_old_dentry);
626 dget(lower_new_dentry);
627 lower_old_dir_dentry = dget_parent(lower_old_dentry);
628 lower_new_dir_dentry = dget_parent(lower_new_dentry);
629 trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
630 /* source should not be ancestor of target */
631 if (trap == lower_old_dentry) {
632 rc = -EINVAL;
633 goto out_lock;
634 }
635 /* target should not be ancestor of source */
636 if (trap == lower_new_dentry) {
637 rc = -ENOTEMPTY;
638 goto out_lock;
639 }
640 rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
641 lower_new_dir_dentry->d_inode, lower_new_dentry);
642 if (rc)
643 goto out_lock;
644 fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode);
645 if (new_dir != old_dir)
646 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode);
647 out_lock:
648 unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
649 dput(lower_new_dir_dentry);
650 dput(lower_old_dir_dentry);
651 dput(lower_new_dentry);
652 dput(lower_old_dentry);
653 return rc;
654 }
655
656 static int ecryptfs_readlink_lower(struct dentry *dentry, char **buf,
657 size_t *bufsiz)
658 {
659 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
660 char *lower_buf;
661 mm_segment_t old_fs;
662 int rc;
663
664 lower_buf = kmalloc(PATH_MAX, GFP_KERNEL);
665 if (!lower_buf) {
666 rc = -ENOMEM;
667 goto out;
668 }
669 old_fs = get_fs();
670 set_fs(get_ds());
671 rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
672 (char __user *)lower_buf,
673 PATH_MAX);
674 set_fs(old_fs);
675 if (rc < 0)
676 goto out;
677 rc = ecryptfs_decode_and_decrypt_filename(buf, bufsiz, dentry,
678 lower_buf, rc);
679 out:
680 kfree(lower_buf);
681 return rc;
682 }
683
684 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
685 {
686 char *buf;
687 size_t len = PATH_MAX;
688 int rc;
689
690 rc = ecryptfs_readlink_lower(dentry, &buf, &len);
691 if (rc)
692 goto out;
693 fsstack_copy_attr_atime(dentry->d_inode,
694 ecryptfs_dentry_to_lower(dentry)->d_inode);
695 buf[len] = '\0';
696 out:
697 nd_set_link(nd, buf);
698 return NULL;
699 }
700
701 static void
702 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
703 {
704 char *buf = nd_get_link(nd);
705 if (!IS_ERR(buf)) {
706 /* Free the char* */
707 kfree(buf);
708 }
709 }
710
711 /**
712 * upper_size_to_lower_size
713 * @crypt_stat: Crypt_stat associated with file
714 * @upper_size: Size of the upper file
715 *
716 * Calculate the required size of the lower file based on the
717 * specified size of the upper file. This calculation is based on the
718 * number of headers in the underlying file and the extent size.
719 *
720 * Returns Calculated size of the lower file.
721 */
722 static loff_t
723 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
724 loff_t upper_size)
725 {
726 loff_t lower_size;
727
728 lower_size = ecryptfs_lower_header_size(crypt_stat);
729 if (upper_size != 0) {
730 loff_t num_extents;
731
732 num_extents = upper_size >> crypt_stat->extent_shift;
733 if (upper_size & ~crypt_stat->extent_mask)
734 num_extents++;
735 lower_size += (num_extents * crypt_stat->extent_size);
736 }
737 return lower_size;
738 }
739
740 /**
741 * truncate_upper
742 * @dentry: The ecryptfs layer dentry
743 * @ia: Address of the ecryptfs inode's attributes
744 * @lower_ia: Address of the lower inode's attributes
745 *
746 * Function to handle truncations modifying the size of the file. Note
747 * that the file sizes are interpolated. When expanding, we are simply
748 * writing strings of 0's out. When truncating, we truncate the upper
749 * inode and update the lower_ia according to the page index
750 * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
751 * the caller must use lower_ia in a call to notify_change() to perform
752 * the truncation of the lower inode.
753 *
754 * Returns zero on success; non-zero otherwise
755 */
756 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
757 struct iattr *lower_ia)
758 {
759 int rc = 0;
760 struct inode *inode = dentry->d_inode;
761 struct ecryptfs_crypt_stat *crypt_stat;
762 loff_t i_size = i_size_read(inode);
763 loff_t lower_size_before_truncate;
764 loff_t lower_size_after_truncate;
765
766 if (unlikely((ia->ia_size == i_size))) {
767 lower_ia->ia_valid &= ~ATTR_SIZE;
768 return 0;
769 }
770 rc = ecryptfs_get_lower_file(dentry, inode);
771 if (rc)
772 return rc;
773 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
774 /* Switch on growing or shrinking file */
775 if (ia->ia_size > i_size) {
776 char zero[] = { 0x00 };
777
778 lower_ia->ia_valid &= ~ATTR_SIZE;
779 /* Write a single 0 at the last position of the file;
780 * this triggers code that will fill in 0's throughout
781 * the intermediate portion of the previous end of the
782 * file and the new and of the file */
783 rc = ecryptfs_write(inode, zero,
784 (ia->ia_size - 1), 1);
785 } else { /* ia->ia_size < i_size_read(inode) */
786 /* We're chopping off all the pages down to the page
787 * in which ia->ia_size is located. Fill in the end of
788 * that page from (ia->ia_size & ~PAGE_CACHE_MASK) to
789 * PAGE_CACHE_SIZE with zeros. */
790 size_t num_zeros = (PAGE_CACHE_SIZE
791 - (ia->ia_size & ~PAGE_CACHE_MASK));
792
793 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
794 truncate_setsize(inode, ia->ia_size);
795 lower_ia->ia_size = ia->ia_size;
796 lower_ia->ia_valid |= ATTR_SIZE;
797 goto out;
798 }
799 if (num_zeros) {
800 char *zeros_virt;
801
802 zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
803 if (!zeros_virt) {
804 rc = -ENOMEM;
805 goto out;
806 }
807 rc = ecryptfs_write(inode, zeros_virt,
808 ia->ia_size, num_zeros);
809 kfree(zeros_virt);
810 if (rc) {
811 printk(KERN_ERR "Error attempting to zero out "
812 "the remainder of the end page on "
813 "reducing truncate; rc = [%d]\n", rc);
814 goto out;
815 }
816 }
817 truncate_setsize(inode, ia->ia_size);
818 rc = ecryptfs_write_inode_size_to_metadata(inode);
819 if (rc) {
820 printk(KERN_ERR "Problem with "
821 "ecryptfs_write_inode_size_to_metadata; "
822 "rc = [%d]\n", rc);
823 goto out;
824 }
825 /* We are reducing the size of the ecryptfs file, and need to
826 * know if we need to reduce the size of the lower file. */
827 lower_size_before_truncate =
828 upper_size_to_lower_size(crypt_stat, i_size);
829 lower_size_after_truncate =
830 upper_size_to_lower_size(crypt_stat, ia->ia_size);
831 if (lower_size_after_truncate < lower_size_before_truncate) {
832 lower_ia->ia_size = lower_size_after_truncate;
833 lower_ia->ia_valid |= ATTR_SIZE;
834 } else
835 lower_ia->ia_valid &= ~ATTR_SIZE;
836 }
837 out:
838 ecryptfs_put_lower_file(inode);
839 return rc;
840 }
841
842 static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset)
843 {
844 struct ecryptfs_crypt_stat *crypt_stat;
845 loff_t lower_oldsize, lower_newsize;
846
847 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
848 lower_oldsize = upper_size_to_lower_size(crypt_stat,
849 i_size_read(inode));
850 lower_newsize = upper_size_to_lower_size(crypt_stat, offset);
851 if (lower_newsize > lower_oldsize) {
852 /*
853 * The eCryptfs inode and the new *lower* size are mixed here
854 * because we may not have the lower i_mutex held and/or it may
855 * not be appropriate to call inode_newsize_ok() with inodes
856 * from other filesystems.
857 */
858 return inode_newsize_ok(inode, lower_newsize);
859 }
860
861 return 0;
862 }
863
864 /**
865 * ecryptfs_truncate
866 * @dentry: The ecryptfs layer dentry
867 * @new_length: The length to expand the file to
868 *
869 * Simple function that handles the truncation of an eCryptfs inode and
870 * its corresponding lower inode.
871 *
872 * Returns zero on success; non-zero otherwise
873 */
874 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
875 {
876 struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
877 struct iattr lower_ia = { .ia_valid = 0 };
878 int rc;
879
880 rc = ecryptfs_inode_newsize_ok(dentry->d_inode, new_length);
881 if (rc)
882 return rc;
883
884 rc = truncate_upper(dentry, &ia, &lower_ia);
885 if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
886 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
887
888 mutex_lock(&lower_dentry->d_inode->i_mutex);
889 rc = notify_change(lower_dentry, &lower_ia);
890 mutex_unlock(&lower_dentry->d_inode->i_mutex);
891 }
892 return rc;
893 }
894
895 static int
896 ecryptfs_permission(struct inode *inode, int mask)
897 {
898 return inode_permission(ecryptfs_inode_to_lower(inode), mask);
899 }
900
901 /**
902 * ecryptfs_setattr
903 * @dentry: dentry handle to the inode to modify
904 * @ia: Structure with flags of what to change and values
905 *
906 * Updates the metadata of an inode. If the update is to the size
907 * i.e. truncation, then ecryptfs_truncate will handle the size modification
908 * of both the ecryptfs inode and the lower inode.
909 *
910 * All other metadata changes will be passed right to the lower filesystem,
911 * and we will just update our inode to look like the lower.
912 */
913 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
914 {
915 int rc = 0;
916 struct dentry *lower_dentry;
917 struct iattr lower_ia;
918 struct inode *inode;
919 struct inode *lower_inode;
920 struct ecryptfs_crypt_stat *crypt_stat;
921
922 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
923 if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
924 ecryptfs_init_crypt_stat(crypt_stat);
925 inode = dentry->d_inode;
926 lower_inode = ecryptfs_inode_to_lower(inode);
927 lower_dentry = ecryptfs_dentry_to_lower(dentry);
928 mutex_lock(&crypt_stat->cs_mutex);
929 if (S_ISDIR(dentry->d_inode->i_mode))
930 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
931 else if (S_ISREG(dentry->d_inode->i_mode)
932 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
933 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
934 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
935
936 mount_crypt_stat = &ecryptfs_superblock_to_private(
937 dentry->d_sb)->mount_crypt_stat;
938 rc = ecryptfs_get_lower_file(dentry, inode);
939 if (rc) {
940 mutex_unlock(&crypt_stat->cs_mutex);
941 goto out;
942 }
943 rc = ecryptfs_read_metadata(dentry);
944 ecryptfs_put_lower_file(inode);
945 if (rc) {
946 if (!(mount_crypt_stat->flags
947 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
948 rc = -EIO;
949 printk(KERN_WARNING "Either the lower file "
950 "is not in a valid eCryptfs format, "
951 "or the key could not be retrieved. "
952 "Plaintext passthrough mode is not "
953 "enabled; returning -EIO\n");
954 mutex_unlock(&crypt_stat->cs_mutex);
955 goto out;
956 }
957 rc = 0;
958 crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
959 | ECRYPTFS_ENCRYPTED);
960 }
961 }
962 mutex_unlock(&crypt_stat->cs_mutex);
963
964 rc = inode_change_ok(inode, ia);
965 if (rc)
966 goto out;
967 if (ia->ia_valid & ATTR_SIZE) {
968 rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size);
969 if (rc)
970 goto out;
971 }
972
973 memcpy(&lower_ia, ia, sizeof(lower_ia));
974 if (ia->ia_valid & ATTR_FILE)
975 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
976 if (ia->ia_valid & ATTR_SIZE) {
977 rc = truncate_upper(dentry, ia, &lower_ia);
978 if (rc < 0)
979 goto out;
980 }
981
982 /*
983 * mode change is for clearing setuid/setgid bits. Allow lower fs
984 * to interpret this in its own way.
985 */
986 if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
987 lower_ia.ia_valid &= ~ATTR_MODE;
988
989 mutex_lock(&lower_dentry->d_inode->i_mutex);
990 rc = notify_change(lower_dentry, &lower_ia);
991 mutex_unlock(&lower_dentry->d_inode->i_mutex);
992 out:
993 fsstack_copy_attr_all(inode, lower_inode);
994 return rc;
995 }
996
997 int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
998 struct kstat *stat)
999 {
1000 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
1001 int rc = 0;
1002
1003 mount_crypt_stat = &ecryptfs_superblock_to_private(
1004 dentry->d_sb)->mount_crypt_stat;
1005 generic_fillattr(dentry->d_inode, stat);
1006 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
1007 char *target;
1008 size_t targetsiz;
1009
1010 rc = ecryptfs_readlink_lower(dentry, &target, &targetsiz);
1011 if (!rc) {
1012 kfree(target);
1013 stat->size = targetsiz;
1014 }
1015 }
1016 return rc;
1017 }
1018
1019 int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
1020 struct kstat *stat)
1021 {
1022 struct kstat lower_stat;
1023 int rc;
1024
1025 rc = vfs_getattr(ecryptfs_dentry_to_lower_mnt(dentry),
1026 ecryptfs_dentry_to_lower(dentry), &lower_stat);
1027 if (!rc) {
1028 fsstack_copy_attr_all(dentry->d_inode,
1029 ecryptfs_inode_to_lower(dentry->d_inode));
1030 generic_fillattr(dentry->d_inode, stat);
1031 stat->blocks = lower_stat.blocks;
1032 }
1033 return rc;
1034 }
1035
1036 int
1037 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
1038 size_t size, int flags)
1039 {
1040 int rc = 0;
1041 struct dentry *lower_dentry;
1042
1043 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1044 if (!lower_dentry->d_inode->i_op->setxattr) {
1045 rc = -EOPNOTSUPP;
1046 goto out;
1047 }
1048
1049 rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1050 if (!rc)
1051 fsstack_copy_attr_all(dentry->d_inode, lower_dentry->d_inode);
1052 out:
1053 return rc;
1054 }
1055
1056 ssize_t
1057 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
1058 void *value, size_t size)
1059 {
1060 int rc = 0;
1061
1062 if (!lower_dentry->d_inode->i_op->getxattr) {
1063 rc = -EOPNOTSUPP;
1064 goto out;
1065 }
1066 mutex_lock(&lower_dentry->d_inode->i_mutex);
1067 rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
1068 size);
1069 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1070 out:
1071 return rc;
1072 }
1073
1074 static ssize_t
1075 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
1076 size_t size)
1077 {
1078 return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
1079 value, size);
1080 }
1081
1082 static ssize_t
1083 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1084 {
1085 int rc = 0;
1086 struct dentry *lower_dentry;
1087
1088 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1089 if (!lower_dentry->d_inode->i_op->listxattr) {
1090 rc = -EOPNOTSUPP;
1091 goto out;
1092 }
1093 mutex_lock(&lower_dentry->d_inode->i_mutex);
1094 rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1095 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1096 out:
1097 return rc;
1098 }
1099
1100 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1101 {
1102 int rc = 0;
1103 struct dentry *lower_dentry;
1104
1105 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1106 if (!lower_dentry->d_inode->i_op->removexattr) {
1107 rc = -EOPNOTSUPP;
1108 goto out;
1109 }
1110 mutex_lock(&lower_dentry->d_inode->i_mutex);
1111 rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1112 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1113 out:
1114 return rc;
1115 }
1116
1117 const struct inode_operations ecryptfs_symlink_iops = {
1118 .readlink = generic_readlink,
1119 .follow_link = ecryptfs_follow_link,
1120 .put_link = ecryptfs_put_link,
1121 .permission = ecryptfs_permission,
1122 .setattr = ecryptfs_setattr,
1123 .getattr = ecryptfs_getattr_link,
1124 .setxattr = ecryptfs_setxattr,
1125 .getxattr = ecryptfs_getxattr,
1126 .listxattr = ecryptfs_listxattr,
1127 .removexattr = ecryptfs_removexattr
1128 };
1129
1130 const struct inode_operations ecryptfs_dir_iops = {
1131 .create = ecryptfs_create,
1132 .lookup = ecryptfs_lookup,
1133 .link = ecryptfs_link,
1134 .unlink = ecryptfs_unlink,
1135 .symlink = ecryptfs_symlink,
1136 .mkdir = ecryptfs_mkdir,
1137 .rmdir = ecryptfs_rmdir,
1138 .mknod = ecryptfs_mknod,
1139 .rename = ecryptfs_rename,
1140 .permission = ecryptfs_permission,
1141 .setattr = ecryptfs_setattr,
1142 .setxattr = ecryptfs_setxattr,
1143 .getxattr = ecryptfs_getxattr,
1144 .listxattr = ecryptfs_listxattr,
1145 .removexattr = ecryptfs_removexattr
1146 };
1147
1148 const struct inode_operations ecryptfs_main_iops = {
1149 .permission = ecryptfs_permission,
1150 .setattr = ecryptfs_setattr,
1151 .getattr = ecryptfs_getattr,
1152 .setxattr = ecryptfs_setxattr,
1153 .getxattr = ecryptfs_getxattr,
1154 .listxattr = ecryptfs_listxattr,
1155 .removexattr = ecryptfs_removexattr
1156 };
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