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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
39static 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
48static void unlock_dir(struct dentry *dir)
49{
50 mutex_unlock(&dir->d_inode->i_mutex);
51 dput(dir);
52}
53
54static 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
61static 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
91static 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
113struct 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 */
134static 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/**
147 * ecryptfs_do_create
148 * @directory_inode: inode of the new file's dentry's parent in ecryptfs
149 * @ecryptfs_dentry: New file's dentry in ecryptfs
150 * @mode: The mode of the new file
151 * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
152 *
153 * Creates the underlying file and the eCryptfs inode which will link to
154 * it. It will also update the eCryptfs directory inode to mimic the
155 * stat of the lower directory inode.
156 *
157 * Returns the new eCryptfs inode on success; an ERR_PTR on error condition
158 */
159static struct inode *
160ecryptfs_do_create(struct inode *directory_inode,
161 struct dentry *ecryptfs_dentry, umode_t mode)
162{
163 int rc;
164 struct dentry *lower_dentry;
165 struct dentry *lower_dir_dentry;
166 struct inode *inode;
167
168 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
169 lower_dir_dentry = lock_parent(lower_dentry);
170 if (IS_ERR(lower_dir_dentry)) {
171 ecryptfs_printk(KERN_ERR, "Error locking directory of "
172 "dentry\n");
173 inode = ERR_CAST(lower_dir_dentry);
174 goto out;
175 }
176 rc = vfs_create(lower_dir_dentry->d_inode, lower_dentry, mode, NULL);
177 if (rc) {
178 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
179 "rc = [%d]\n", __func__, rc);
180 inode = ERR_PTR(rc);
181 goto out_lock;
182 }
183 inode = __ecryptfs_get_inode(lower_dentry->d_inode,
184 directory_inode->i_sb);
185 if (IS_ERR(inode))
186 goto out_lock;
187 fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
188 fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode);
189out_lock:
190 unlock_dir(lower_dir_dentry);
191out:
192 return inode;
193}
194
195/**
196 * ecryptfs_initialize_file
197 *
198 * Cause the file to be changed from a basic empty file to an ecryptfs
199 * file with a header and first data page.
200 *
201 * Returns zero on success
202 */
203static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry,
204 struct inode *ecryptfs_inode)
205{
206 struct ecryptfs_crypt_stat *crypt_stat =
207 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
208 int rc = 0;
209
210 if (S_ISDIR(ecryptfs_inode->i_mode)) {
211 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
212 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
213 goto out;
214 }
215 ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
216 rc = ecryptfs_new_file_context(ecryptfs_inode);
217 if (rc) {
218 ecryptfs_printk(KERN_ERR, "Error creating new file "
219 "context; rc = [%d]\n", rc);
220 goto out;
221 }
222 rc = ecryptfs_get_lower_file(ecryptfs_dentry, ecryptfs_inode);
223 if (rc) {
224 printk(KERN_ERR "%s: Error attempting to initialize "
225 "the lower file for the dentry with name "
226 "[%s]; rc = [%d]\n", __func__,
227 ecryptfs_dentry->d_name.name, rc);
228 goto out;
229 }
230 rc = ecryptfs_write_metadata(ecryptfs_dentry, ecryptfs_inode);
231 if (rc)
232 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
233 ecryptfs_put_lower_file(ecryptfs_inode);
234out:
235 return rc;
236}
237
238/**
239 * ecryptfs_create
240 * @dir: The inode of the directory in which to create the file.
241 * @dentry: The eCryptfs dentry
242 * @mode: The mode of the new file.
243 * @nd: nameidata
244 *
245 * Creates a new file.
246 *
247 * Returns zero on success; non-zero on error condition
248 */
249static int
250ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
251 umode_t mode, struct nameidata *nd)
252{
253 struct inode *ecryptfs_inode;
254 int rc;
255
256 ecryptfs_inode = ecryptfs_do_create(directory_inode, ecryptfs_dentry,
257 mode);
258 if (unlikely(IS_ERR(ecryptfs_inode))) {
259 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
260 "lower filesystem\n");
261 rc = PTR_ERR(ecryptfs_inode);
262 goto out;
263 }
264 /* At this point, a file exists on "disk"; we need to make sure
265 * that this on disk file is prepared to be an ecryptfs file */
266 rc = ecryptfs_initialize_file(ecryptfs_dentry, ecryptfs_inode);
267 if (rc) {
268 drop_nlink(ecryptfs_inode);
269 unlock_new_inode(ecryptfs_inode);
270 iput(ecryptfs_inode);
271 goto out;
272 }
273 d_instantiate(ecryptfs_dentry, ecryptfs_inode);
274 unlock_new_inode(ecryptfs_inode);
275out:
276 return rc;
277}
278
279static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode)
280{
281 struct ecryptfs_crypt_stat *crypt_stat;
282 int rc;
283
284 rc = ecryptfs_get_lower_file(dentry, inode);
285 if (rc) {
286 printk(KERN_ERR "%s: Error attempting to initialize "
287 "the lower file for the dentry with name "
288 "[%s]; rc = [%d]\n", __func__,
289 dentry->d_name.name, rc);
290 return rc;
291 }
292
293 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
294 /* TODO: lock for crypt_stat comparison */
295 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
296 ecryptfs_set_default_sizes(crypt_stat);
297
298 rc = ecryptfs_read_and_validate_header_region(inode);
299 ecryptfs_put_lower_file(inode);
300 if (rc) {
301 rc = ecryptfs_read_and_validate_xattr_region(dentry, inode);
302 if (!rc)
303 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
304 }
305
306 /* Must return 0 to allow non-eCryptfs files to be looked up, too */
307 return 0;
308}
309
310/**
311 * ecryptfs_lookup_interpose - Dentry interposition for a lookup
312 */
313static int ecryptfs_lookup_interpose(struct dentry *dentry,
314 struct dentry *lower_dentry,
315 struct inode *dir_inode)
316{
317 struct inode *inode, *lower_inode = lower_dentry->d_inode;
318 struct ecryptfs_dentry_info *dentry_info;
319 struct vfsmount *lower_mnt;
320 int rc = 0;
321
322 lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
323 fsstack_copy_attr_atime(dir_inode, lower_dentry->d_parent->d_inode);
324 BUG_ON(!lower_dentry->d_count);
325
326 dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
327 ecryptfs_set_dentry_private(dentry, dentry_info);
328 if (!dentry_info) {
329 printk(KERN_ERR "%s: Out of memory whilst attempting "
330 "to allocate ecryptfs_dentry_info struct\n",
331 __func__);
332 dput(lower_dentry);
333 mntput(lower_mnt);
334 d_drop(dentry);
335 return -ENOMEM;
336 }
337 ecryptfs_set_dentry_lower(dentry, lower_dentry);
338 ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
339
340 if (!lower_dentry->d_inode) {
341 /* We want to add because we couldn't find in lower */
342 d_add(dentry, NULL);
343 return 0;
344 }
345 inode = __ecryptfs_get_inode(lower_inode, dir_inode->i_sb);
346 if (IS_ERR(inode)) {
347 printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
348 __func__, PTR_ERR(inode));
349 return PTR_ERR(inode);
350 }
351 if (S_ISREG(inode->i_mode)) {
352 rc = ecryptfs_i_size_read(dentry, inode);
353 if (rc) {
354 make_bad_inode(inode);
355 return rc;
356 }
357 }
358
359 if (inode->i_state & I_NEW)
360 unlock_new_inode(inode);
361 d_add(dentry, inode);
362
363 return rc;
364}
365
366/**
367 * ecryptfs_lookup
368 * @ecryptfs_dir_inode: The eCryptfs directory inode
369 * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
370 * @ecryptfs_nd: nameidata; may be NULL
371 *
372 * Find a file on disk. If the file does not exist, then we'll add it to the
373 * dentry cache and continue on to read it from the disk.
374 */
375static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
376 struct dentry *ecryptfs_dentry,
377 struct nameidata *ecryptfs_nd)
378{
379 char *encrypted_and_encoded_name = NULL;
380 size_t encrypted_and_encoded_name_size;
381 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
382 struct dentry *lower_dir_dentry, *lower_dentry;
383 int rc = 0;
384
385 if ((ecryptfs_dentry->d_name.len == 1
386 && !strcmp(ecryptfs_dentry->d_name.name, "."))
387 || (ecryptfs_dentry->d_name.len == 2
388 && !strcmp(ecryptfs_dentry->d_name.name, ".."))) {
389 goto out_d_drop;
390 }
391 lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
392 mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
393 lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name,
394 lower_dir_dentry,
395 ecryptfs_dentry->d_name.len);
396 mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
397 if (IS_ERR(lower_dentry)) {
398 rc = PTR_ERR(lower_dentry);
399 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
400 "[%d] on lower_dentry = [%s]\n", __func__, rc,
401 encrypted_and_encoded_name);
402 goto out_d_drop;
403 }
404 if (lower_dentry->d_inode)
405 goto interpose;
406 mount_crypt_stat = &ecryptfs_superblock_to_private(
407 ecryptfs_dentry->d_sb)->mount_crypt_stat;
408 if (!(mount_crypt_stat
409 && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)))
410 goto interpose;
411 dput(lower_dentry);
412 rc = ecryptfs_encrypt_and_encode_filename(
413 &encrypted_and_encoded_name, &encrypted_and_encoded_name_size,
414 NULL, mount_crypt_stat, ecryptfs_dentry->d_name.name,
415 ecryptfs_dentry->d_name.len);
416 if (rc) {
417 printk(KERN_ERR "%s: Error attempting to encrypt and encode "
418 "filename; rc = [%d]\n", __func__, rc);
419 goto out_d_drop;
420 }
421 mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
422 lower_dentry = lookup_one_len(encrypted_and_encoded_name,
423 lower_dir_dentry,
424 encrypted_and_encoded_name_size);
425 mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
426 if (IS_ERR(lower_dentry)) {
427 rc = PTR_ERR(lower_dentry);
428 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
429 "[%d] on lower_dentry = [%s]\n", __func__, rc,
430 encrypted_and_encoded_name);
431 goto out_d_drop;
432 }
433interpose:
434 rc = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry,
435 ecryptfs_dir_inode);
436 goto out;
437out_d_drop:
438 d_drop(ecryptfs_dentry);
439out:
440 kfree(encrypted_and_encoded_name);
441 return ERR_PTR(rc);
442}
443
444static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
445 struct dentry *new_dentry)
446{
447 struct dentry *lower_old_dentry;
448 struct dentry *lower_new_dentry;
449 struct dentry *lower_dir_dentry;
450 u64 file_size_save;
451 int rc;
452
453 file_size_save = i_size_read(old_dentry->d_inode);
454 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
455 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
456 dget(lower_old_dentry);
457 dget(lower_new_dentry);
458 lower_dir_dentry = lock_parent(lower_new_dentry);
459 rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
460 lower_new_dentry);
461 if (rc || !lower_new_dentry->d_inode)
462 goto out_lock;
463 rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
464 if (rc)
465 goto out_lock;
466 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
467 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
468 set_nlink(old_dentry->d_inode,
469 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink);
470 i_size_write(new_dentry->d_inode, file_size_save);
471out_lock:
472 unlock_dir(lower_dir_dentry);
473 dput(lower_new_dentry);
474 dput(lower_old_dentry);
475 return rc;
476}
477
478static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
479{
480 int rc = 0;
481 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
482 struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
483 struct dentry *lower_dir_dentry;
484
485 dget(lower_dentry);
486 lower_dir_dentry = lock_parent(lower_dentry);
487 rc = vfs_unlink(lower_dir_inode, lower_dentry);
488 if (rc) {
489 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
490 goto out_unlock;
491 }
492 fsstack_copy_attr_times(dir, lower_dir_inode);
493 set_nlink(dentry->d_inode,
494 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink);
495 dentry->d_inode->i_ctime = dir->i_ctime;
496 d_drop(dentry);
497out_unlock:
498 unlock_dir(lower_dir_dentry);
499 dput(lower_dentry);
500 return rc;
501}
502
503static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
504 const char *symname)
505{
506 int rc;
507 struct dentry *lower_dentry;
508 struct dentry *lower_dir_dentry;
509 char *encoded_symname;
510 size_t encoded_symlen;
511 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
512
513 lower_dentry = ecryptfs_dentry_to_lower(dentry);
514 dget(lower_dentry);
515 lower_dir_dentry = lock_parent(lower_dentry);
516 mount_crypt_stat = &ecryptfs_superblock_to_private(
517 dir->i_sb)->mount_crypt_stat;
518 rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
519 &encoded_symlen,
520 NULL,
521 mount_crypt_stat, symname,
522 strlen(symname));
523 if (rc)
524 goto out_lock;
525 rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
526 encoded_symname);
527 kfree(encoded_symname);
528 if (rc || !lower_dentry->d_inode)
529 goto out_lock;
530 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
531 if (rc)
532 goto out_lock;
533 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
534 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
535out_lock:
536 unlock_dir(lower_dir_dentry);
537 dput(lower_dentry);
538 if (!dentry->d_inode)
539 d_drop(dentry);
540 return rc;
541}
542
543static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
544{
545 int rc;
546 struct dentry *lower_dentry;
547 struct dentry *lower_dir_dentry;
548
549 lower_dentry = ecryptfs_dentry_to_lower(dentry);
550 lower_dir_dentry = lock_parent(lower_dentry);
551 rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
552 if (rc || !lower_dentry->d_inode)
553 goto out;
554 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
555 if (rc)
556 goto out;
557 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
558 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
559 set_nlink(dir, lower_dir_dentry->d_inode->i_nlink);
560out:
561 unlock_dir(lower_dir_dentry);
562 if (!dentry->d_inode)
563 d_drop(dentry);
564 return rc;
565}
566
567static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
568{
569 struct dentry *lower_dentry;
570 struct dentry *lower_dir_dentry;
571 int rc;
572
573 lower_dentry = ecryptfs_dentry_to_lower(dentry);
574 dget(dentry);
575 lower_dir_dentry = lock_parent(lower_dentry);
576 dget(lower_dentry);
577 rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
578 dput(lower_dentry);
579 if (!rc && dentry->d_inode)
580 clear_nlink(dentry->d_inode);
581 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
582 set_nlink(dir, lower_dir_dentry->d_inode->i_nlink);
583 unlock_dir(lower_dir_dentry);
584 if (!rc)
585 d_drop(dentry);
586 dput(dentry);
587 return rc;
588}
589
590static int
591ecryptfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
592{
593 int rc;
594 struct dentry *lower_dentry;
595 struct dentry *lower_dir_dentry;
596
597 lower_dentry = ecryptfs_dentry_to_lower(dentry);
598 lower_dir_dentry = lock_parent(lower_dentry);
599 rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
600 if (rc || !lower_dentry->d_inode)
601 goto out;
602 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
603 if (rc)
604 goto out;
605 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
606 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
607out:
608 unlock_dir(lower_dir_dentry);
609 if (!dentry->d_inode)
610 d_drop(dentry);
611 return rc;
612}
613
614static int
615ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
616 struct inode *new_dir, struct dentry *new_dentry)
617{
618 int rc;
619 struct dentry *lower_old_dentry;
620 struct dentry *lower_new_dentry;
621 struct dentry *lower_old_dir_dentry;
622 struct dentry *lower_new_dir_dentry;
623 struct dentry *trap = NULL;
624 struct inode *target_inode;
625
626 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
627 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
628 dget(lower_old_dentry);
629 dget(lower_new_dentry);
630 lower_old_dir_dentry = dget_parent(lower_old_dentry);
631 lower_new_dir_dentry = dget_parent(lower_new_dentry);
632 target_inode = new_dentry->d_inode;
633 trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
634 /* source should not be ancestor of target */
635 if (trap == lower_old_dentry) {
636 rc = -EINVAL;
637 goto out_lock;
638 }
639 /* target should not be ancestor of source */
640 if (trap == lower_new_dentry) {
641 rc = -ENOTEMPTY;
642 goto out_lock;
643 }
644 rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
645 lower_new_dir_dentry->d_inode, lower_new_dentry);
646 if (rc)
647 goto out_lock;
648 if (target_inode)
649 fsstack_copy_attr_all(target_inode,
650 ecryptfs_inode_to_lower(target_inode));
651 fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode);
652 if (new_dir != old_dir)
653 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode);
654out_lock:
655 unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
656 dput(lower_new_dir_dentry);
657 dput(lower_old_dir_dentry);
658 dput(lower_new_dentry);
659 dput(lower_old_dentry);
660 return rc;
661}
662
663static int ecryptfs_readlink_lower(struct dentry *dentry, char **buf,
664 size_t *bufsiz)
665{
666 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
667 char *lower_buf;
668 mm_segment_t old_fs;
669 int rc;
670
671 lower_buf = kmalloc(PATH_MAX, GFP_KERNEL);
672 if (!lower_buf) {
673 rc = -ENOMEM;
674 goto out;
675 }
676 old_fs = get_fs();
677 set_fs(get_ds());
678 rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
679 (char __user *)lower_buf,
680 PATH_MAX);
681 set_fs(old_fs);
682 if (rc < 0)
683 goto out;
684 rc = ecryptfs_decode_and_decrypt_filename(buf, bufsiz, dentry,
685 lower_buf, rc);
686out:
687 kfree(lower_buf);
688 return rc;
689}
690
691static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
692{
693 char *buf;
694 size_t len = PATH_MAX;
695 int rc;
696
697 rc = ecryptfs_readlink_lower(dentry, &buf, &len);
698 if (rc)
699 goto out;
700 fsstack_copy_attr_atime(dentry->d_inode,
701 ecryptfs_dentry_to_lower(dentry)->d_inode);
702 buf[len] = '\0';
703out:
704 nd_set_link(nd, buf);
705 return NULL;
706}
707
708static void
709ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
710{
711 char *buf = nd_get_link(nd);
712 if (!IS_ERR(buf)) {
713 /* Free the char* */
714 kfree(buf);
715 }
716}
717
718/**
719 * upper_size_to_lower_size
720 * @crypt_stat: Crypt_stat associated with file
721 * @upper_size: Size of the upper file
722 *
723 * Calculate the required size of the lower file based on the
724 * specified size of the upper file. This calculation is based on the
725 * number of headers in the underlying file and the extent size.
726 *
727 * Returns Calculated size of the lower file.
728 */
729static loff_t
730upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
731 loff_t upper_size)
732{
733 loff_t lower_size;
734
735 lower_size = ecryptfs_lower_header_size(crypt_stat);
736 if (upper_size != 0) {
737 loff_t num_extents;
738
739 num_extents = upper_size >> crypt_stat->extent_shift;
740 if (upper_size & ~crypt_stat->extent_mask)
741 num_extents++;
742 lower_size += (num_extents * crypt_stat->extent_size);
743 }
744 return lower_size;
745}
746
747/**
748 * truncate_upper
749 * @dentry: The ecryptfs layer dentry
750 * @ia: Address of the ecryptfs inode's attributes
751 * @lower_ia: Address of the lower inode's attributes
752 *
753 * Function to handle truncations modifying the size of the file. Note
754 * that the file sizes are interpolated. When expanding, we are simply
755 * writing strings of 0's out. When truncating, we truncate the upper
756 * inode and update the lower_ia according to the page index
757 * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
758 * the caller must use lower_ia in a call to notify_change() to perform
759 * the truncation of the lower inode.
760 *
761 * Returns zero on success; non-zero otherwise
762 */
763static int truncate_upper(struct dentry *dentry, struct iattr *ia,
764 struct iattr *lower_ia)
765{
766 int rc = 0;
767 struct inode *inode = dentry->d_inode;
768 struct ecryptfs_crypt_stat *crypt_stat;
769 loff_t i_size = i_size_read(inode);
770 loff_t lower_size_before_truncate;
771 loff_t lower_size_after_truncate;
772
773 if (unlikely((ia->ia_size == i_size))) {
774 lower_ia->ia_valid &= ~ATTR_SIZE;
775 return 0;
776 }
777 rc = ecryptfs_get_lower_file(dentry, inode);
778 if (rc)
779 return rc;
780 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
781 /* Switch on growing or shrinking file */
782 if (ia->ia_size > i_size) {
783 char zero[] = { 0x00 };
784
785 lower_ia->ia_valid &= ~ATTR_SIZE;
786 /* Write a single 0 at the last position of the file;
787 * this triggers code that will fill in 0's throughout
788 * the intermediate portion of the previous end of the
789 * file and the new and of the file */
790 rc = ecryptfs_write(inode, zero,
791 (ia->ia_size - 1), 1);
792 } else { /* ia->ia_size < i_size_read(inode) */
793 /* We're chopping off all the pages down to the page
794 * in which ia->ia_size is located. Fill in the end of
795 * that page from (ia->ia_size & ~PAGE_CACHE_MASK) to
796 * PAGE_CACHE_SIZE with zeros. */
797 size_t num_zeros = (PAGE_CACHE_SIZE
798 - (ia->ia_size & ~PAGE_CACHE_MASK));
799
800 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
801 truncate_setsize(inode, ia->ia_size);
802 lower_ia->ia_size = ia->ia_size;
803 lower_ia->ia_valid |= ATTR_SIZE;
804 goto out;
805 }
806 if (num_zeros) {
807 char *zeros_virt;
808
809 zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
810 if (!zeros_virt) {
811 rc = -ENOMEM;
812 goto out;
813 }
814 rc = ecryptfs_write(inode, zeros_virt,
815 ia->ia_size, num_zeros);
816 kfree(zeros_virt);
817 if (rc) {
818 printk(KERN_ERR "Error attempting to zero out "
819 "the remainder of the end page on "
820 "reducing truncate; rc = [%d]\n", rc);
821 goto out;
822 }
823 }
824 truncate_setsize(inode, ia->ia_size);
825 rc = ecryptfs_write_inode_size_to_metadata(inode);
826 if (rc) {
827 printk(KERN_ERR "Problem with "
828 "ecryptfs_write_inode_size_to_metadata; "
829 "rc = [%d]\n", rc);
830 goto out;
831 }
832 /* We are reducing the size of the ecryptfs file, and need to
833 * know if we need to reduce the size of the lower file. */
834 lower_size_before_truncate =
835 upper_size_to_lower_size(crypt_stat, i_size);
836 lower_size_after_truncate =
837 upper_size_to_lower_size(crypt_stat, ia->ia_size);
838 if (lower_size_after_truncate < lower_size_before_truncate) {
839 lower_ia->ia_size = lower_size_after_truncate;
840 lower_ia->ia_valid |= ATTR_SIZE;
841 } else
842 lower_ia->ia_valid &= ~ATTR_SIZE;
843 }
844out:
845 ecryptfs_put_lower_file(inode);
846 return rc;
847}
848
849static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset)
850{
851 struct ecryptfs_crypt_stat *crypt_stat;
852 loff_t lower_oldsize, lower_newsize;
853
854 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
855 lower_oldsize = upper_size_to_lower_size(crypt_stat,
856 i_size_read(inode));
857 lower_newsize = upper_size_to_lower_size(crypt_stat, offset);
858 if (lower_newsize > lower_oldsize) {
859 /*
860 * The eCryptfs inode and the new *lower* size are mixed here
861 * because we may not have the lower i_mutex held and/or it may
862 * not be appropriate to call inode_newsize_ok() with inodes
863 * from other filesystems.
864 */
865 return inode_newsize_ok(inode, lower_newsize);
866 }
867
868 return 0;
869}
870
871/**
872 * ecryptfs_truncate
873 * @dentry: The ecryptfs layer dentry
874 * @new_length: The length to expand the file to
875 *
876 * Simple function that handles the truncation of an eCryptfs inode and
877 * its corresponding lower inode.
878 *
879 * Returns zero on success; non-zero otherwise
880 */
881int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
882{
883 struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
884 struct iattr lower_ia = { .ia_valid = 0 };
885 int rc;
886
887 rc = ecryptfs_inode_newsize_ok(dentry->d_inode, new_length);
888 if (rc)
889 return rc;
890
891 rc = truncate_upper(dentry, &ia, &lower_ia);
892 if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
893 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
894
895 mutex_lock(&lower_dentry->d_inode->i_mutex);
896 rc = notify_change(lower_dentry, &lower_ia);
897 mutex_unlock(&lower_dentry->d_inode->i_mutex);
898 }
899 return rc;
900}
901
902static int
903ecryptfs_permission(struct inode *inode, int mask)
904{
905 return inode_permission(ecryptfs_inode_to_lower(inode), mask);
906}
907
908/**
909 * ecryptfs_setattr
910 * @dentry: dentry handle to the inode to modify
911 * @ia: Structure with flags of what to change and values
912 *
913 * Updates the metadata of an inode. If the update is to the size
914 * i.e. truncation, then ecryptfs_truncate will handle the size modification
915 * of both the ecryptfs inode and the lower inode.
916 *
917 * All other metadata changes will be passed right to the lower filesystem,
918 * and we will just update our inode to look like the lower.
919 */
920static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
921{
922 int rc = 0;
923 struct dentry *lower_dentry;
924 struct iattr lower_ia;
925 struct inode *inode;
926 struct inode *lower_inode;
927 struct ecryptfs_crypt_stat *crypt_stat;
928
929 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
930 if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
931 ecryptfs_init_crypt_stat(crypt_stat);
932 inode = dentry->d_inode;
933 lower_inode = ecryptfs_inode_to_lower(inode);
934 lower_dentry = ecryptfs_dentry_to_lower(dentry);
935 mutex_lock(&crypt_stat->cs_mutex);
936 if (S_ISDIR(dentry->d_inode->i_mode))
937 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
938 else if (S_ISREG(dentry->d_inode->i_mode)
939 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
940 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
941 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
942
943 mount_crypt_stat = &ecryptfs_superblock_to_private(
944 dentry->d_sb)->mount_crypt_stat;
945 rc = ecryptfs_get_lower_file(dentry, inode);
946 if (rc) {
947 mutex_unlock(&crypt_stat->cs_mutex);
948 goto out;
949 }
950 rc = ecryptfs_read_metadata(dentry);
951 ecryptfs_put_lower_file(inode);
952 if (rc) {
953 if (!(mount_crypt_stat->flags
954 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
955 rc = -EIO;
956 printk(KERN_WARNING "Either the lower file "
957 "is not in a valid eCryptfs format, "
958 "or the key could not be retrieved. "
959 "Plaintext passthrough mode is not "
960 "enabled; returning -EIO\n");
961 mutex_unlock(&crypt_stat->cs_mutex);
962 goto out;
963 }
964 rc = 0;
965 crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
966 | ECRYPTFS_ENCRYPTED);
967 }
968 }
969 mutex_unlock(&crypt_stat->cs_mutex);
970
971 rc = inode_change_ok(inode, ia);
972 if (rc)
973 goto out;
974 if (ia->ia_valid & ATTR_SIZE) {
975 rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size);
976 if (rc)
977 goto out;
978 }
979
980 if (S_ISREG(inode->i_mode)) {
981 rc = filemap_write_and_wait(inode->i_mapping);
982 if (rc)
983 goto out;
984 fsstack_copy_attr_all(inode, lower_inode);
985 }
986 memcpy(&lower_ia, ia, sizeof(lower_ia));
987 if (ia->ia_valid & ATTR_FILE)
988 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
989 if (ia->ia_valid & ATTR_SIZE) {
990 rc = truncate_upper(dentry, ia, &lower_ia);
991 if (rc < 0)
992 goto out;
993 }
994
995 /*
996 * mode change is for clearing setuid/setgid bits. Allow lower fs
997 * to interpret this in its own way.
998 */
999 if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
1000 lower_ia.ia_valid &= ~ATTR_MODE;
1001
1002 mutex_lock(&lower_dentry->d_inode->i_mutex);
1003 rc = notify_change(lower_dentry, &lower_ia);
1004 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1005out:
1006 fsstack_copy_attr_all(inode, lower_inode);
1007 return rc;
1008}
1009
1010int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
1011 struct kstat *stat)
1012{
1013 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
1014 int rc = 0;
1015
1016 mount_crypt_stat = &ecryptfs_superblock_to_private(
1017 dentry->d_sb)->mount_crypt_stat;
1018 generic_fillattr(dentry->d_inode, stat);
1019 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
1020 char *target;
1021 size_t targetsiz;
1022
1023 rc = ecryptfs_readlink_lower(dentry, &target, &targetsiz);
1024 if (!rc) {
1025 kfree(target);
1026 stat->size = targetsiz;
1027 }
1028 }
1029 return rc;
1030}
1031
1032int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
1033 struct kstat *stat)
1034{
1035 struct kstat lower_stat;
1036 int rc;
1037
1038 rc = vfs_getattr(ecryptfs_dentry_to_lower_mnt(dentry),
1039 ecryptfs_dentry_to_lower(dentry), &lower_stat);
1040 if (!rc) {
1041 fsstack_copy_attr_all(dentry->d_inode,
1042 ecryptfs_inode_to_lower(dentry->d_inode));
1043 generic_fillattr(dentry->d_inode, stat);
1044 stat->blocks = lower_stat.blocks;
1045 }
1046 return rc;
1047}
1048
1049int
1050ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
1051 size_t size, int flags)
1052{
1053 int rc = 0;
1054 struct dentry *lower_dentry;
1055
1056 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1057 if (!lower_dentry->d_inode->i_op->setxattr) {
1058 rc = -EOPNOTSUPP;
1059 goto out;
1060 }
1061
1062 rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1063 if (!rc)
1064 fsstack_copy_attr_all(dentry->d_inode, lower_dentry->d_inode);
1065out:
1066 return rc;
1067}
1068
1069ssize_t
1070ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
1071 void *value, size_t size)
1072{
1073 int rc = 0;
1074
1075 if (!lower_dentry->d_inode->i_op->getxattr) {
1076 rc = -EOPNOTSUPP;
1077 goto out;
1078 }
1079 mutex_lock(&lower_dentry->d_inode->i_mutex);
1080 rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
1081 size);
1082 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1083out:
1084 return rc;
1085}
1086
1087static ssize_t
1088ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
1089 size_t size)
1090{
1091 return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
1092 value, size);
1093}
1094
1095static ssize_t
1096ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1097{
1098 int rc = 0;
1099 struct dentry *lower_dentry;
1100
1101 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1102 if (!lower_dentry->d_inode->i_op->listxattr) {
1103 rc = -EOPNOTSUPP;
1104 goto out;
1105 }
1106 mutex_lock(&lower_dentry->d_inode->i_mutex);
1107 rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1108 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1109out:
1110 return rc;
1111}
1112
1113static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1114{
1115 int rc = 0;
1116 struct dentry *lower_dentry;
1117
1118 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1119 if (!lower_dentry->d_inode->i_op->removexattr) {
1120 rc = -EOPNOTSUPP;
1121 goto out;
1122 }
1123 mutex_lock(&lower_dentry->d_inode->i_mutex);
1124 rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1125 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1126out:
1127 return rc;
1128}
1129
1130const struct inode_operations ecryptfs_symlink_iops = {
1131 .readlink = generic_readlink,
1132 .follow_link = ecryptfs_follow_link,
1133 .put_link = ecryptfs_put_link,
1134 .permission = ecryptfs_permission,
1135 .setattr = ecryptfs_setattr,
1136 .getattr = ecryptfs_getattr_link,
1137 .setxattr = ecryptfs_setxattr,
1138 .getxattr = ecryptfs_getxattr,
1139 .listxattr = ecryptfs_listxattr,
1140 .removexattr = ecryptfs_removexattr
1141};
1142
1143const struct inode_operations ecryptfs_dir_iops = {
1144 .create = ecryptfs_create,
1145 .lookup = ecryptfs_lookup,
1146 .link = ecryptfs_link,
1147 .unlink = ecryptfs_unlink,
1148 .symlink = ecryptfs_symlink,
1149 .mkdir = ecryptfs_mkdir,
1150 .rmdir = ecryptfs_rmdir,
1151 .mknod = ecryptfs_mknod,
1152 .rename = ecryptfs_rename,
1153 .permission = ecryptfs_permission,
1154 .setattr = ecryptfs_setattr,
1155 .setxattr = ecryptfs_setxattr,
1156 .getxattr = ecryptfs_getxattr,
1157 .listxattr = ecryptfs_listxattr,
1158 .removexattr = ecryptfs_removexattr
1159};
1160
1161const struct inode_operations ecryptfs_main_iops = {
1162 .permission = ecryptfs_permission,
1163 .setattr = ecryptfs_setattr,
1164 .getattr = ecryptfs_getattr,
1165 .setxattr = ecryptfs_setxattr,
1166 .getxattr = ecryptfs_getxattr,
1167 .listxattr = ecryptfs_listxattr,
1168 .removexattr = ecryptfs_removexattr
1169};