Loading...
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_create_underlying_file
148 * @lower_dir_inode: inode of the parent in the lower fs of the new file
149 * @dentry: New file's dentry
150 * @mode: The mode of the new file
151 *
152 * Creates the file in the lower file system.
153 *
154 * Returns zero on success; non-zero on error condition
155 */
156static int
157ecryptfs_create_underlying_file(struct inode *lower_dir_inode,
158 struct dentry *dentry, int mode)
159{
160 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
161 return vfs_create(lower_dir_inode, lower_dentry, mode, NULL);
162}
163
164/**
165 * ecryptfs_do_create
166 * @directory_inode: inode of the new file's dentry's parent in ecryptfs
167 * @ecryptfs_dentry: New file's dentry in ecryptfs
168 * @mode: The mode of the new file
169 * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
170 *
171 * Creates the underlying file and the eCryptfs inode which will link to
172 * it. It will also update the eCryptfs directory inode to mimic the
173 * stat of the lower directory inode.
174 *
175 * Returns zero on success; non-zero on error condition
176 */
177static int
178ecryptfs_do_create(struct inode *directory_inode,
179 struct dentry *ecryptfs_dentry, int mode)
180{
181 int rc;
182 struct dentry *lower_dentry;
183 struct dentry *lower_dir_dentry;
184
185 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
186 lower_dir_dentry = lock_parent(lower_dentry);
187 if (IS_ERR(lower_dir_dentry)) {
188 ecryptfs_printk(KERN_ERR, "Error locking directory of "
189 "dentry\n");
190 rc = PTR_ERR(lower_dir_dentry);
191 goto out;
192 }
193 rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
194 ecryptfs_dentry, mode);
195 if (rc) {
196 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
197 "rc = [%d]\n", __func__, rc);
198 goto out_lock;
199 }
200 rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
201 directory_inode->i_sb);
202 if (rc) {
203 ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n");
204 goto out_lock;
205 }
206 fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
207 fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode);
208out_lock:
209 unlock_dir(lower_dir_dentry);
210out:
211 return rc;
212}
213
214/**
215 * ecryptfs_initialize_file
216 *
217 * Cause the file to be changed from a basic empty file to an ecryptfs
218 * file with a header and first data page.
219 *
220 * Returns zero on success
221 */
222static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
223{
224 struct ecryptfs_crypt_stat *crypt_stat =
225 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
226 int rc = 0;
227
228 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
229 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
230 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
231 goto out;
232 }
233 ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
234 rc = ecryptfs_new_file_context(ecryptfs_dentry);
235 if (rc) {
236 ecryptfs_printk(KERN_ERR, "Error creating new file "
237 "context; rc = [%d]\n", rc);
238 goto out;
239 }
240 rc = ecryptfs_get_lower_file(ecryptfs_dentry,
241 ecryptfs_dentry->d_inode);
242 if (rc) {
243 printk(KERN_ERR "%s: Error attempting to initialize "
244 "the lower file for the dentry with name "
245 "[%s]; rc = [%d]\n", __func__,
246 ecryptfs_dentry->d_name.name, rc);
247 goto out;
248 }
249 rc = ecryptfs_write_metadata(ecryptfs_dentry);
250 if (rc)
251 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
252 ecryptfs_put_lower_file(ecryptfs_dentry->d_inode);
253out:
254 return rc;
255}
256
257/**
258 * ecryptfs_create
259 * @dir: The inode of the directory in which to create the file.
260 * @dentry: The eCryptfs dentry
261 * @mode: The mode of the new file.
262 * @nd: nameidata
263 *
264 * Creates a new file.
265 *
266 * Returns zero on success; non-zero on error condition
267 */
268static int
269ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
270 int mode, struct nameidata *nd)
271{
272 int rc;
273
274 /* ecryptfs_do_create() calls ecryptfs_interpose() */
275 rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode);
276 if (unlikely(rc)) {
277 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
278 "lower filesystem\n");
279 goto out;
280 }
281 /* At this point, a file exists on "disk"; we need to make sure
282 * that this on disk file is prepared to be an ecryptfs file */
283 rc = ecryptfs_initialize_file(ecryptfs_dentry);
284out:
285 return rc;
286}
287
288static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode)
289{
290 struct ecryptfs_crypt_stat *crypt_stat;
291 int rc;
292
293 rc = ecryptfs_get_lower_file(dentry, inode);
294 if (rc) {
295 printk(KERN_ERR "%s: Error attempting to initialize "
296 "the lower file for the dentry with name "
297 "[%s]; rc = [%d]\n", __func__,
298 dentry->d_name.name, rc);
299 return rc;
300 }
301
302 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
303 /* TODO: lock for crypt_stat comparison */
304 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
305 ecryptfs_set_default_sizes(crypt_stat);
306
307 rc = ecryptfs_read_and_validate_header_region(inode);
308 ecryptfs_put_lower_file(inode);
309 if (rc) {
310 rc = ecryptfs_read_and_validate_xattr_region(dentry, inode);
311 if (!rc)
312 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
313 }
314
315 /* Must return 0 to allow non-eCryptfs files to be looked up, too */
316 return 0;
317}
318
319/**
320 * ecryptfs_lookup_interpose - Dentry interposition for a lookup
321 */
322static int ecryptfs_lookup_interpose(struct dentry *dentry,
323 struct dentry *lower_dentry,
324 struct inode *dir_inode)
325{
326 struct inode *inode, *lower_inode = lower_dentry->d_inode;
327 struct ecryptfs_dentry_info *dentry_info;
328 struct vfsmount *lower_mnt;
329 int rc = 0;
330
331 lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
332 fsstack_copy_attr_atime(dir_inode, lower_dentry->d_parent->d_inode);
333 BUG_ON(!lower_dentry->d_count);
334
335 dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
336 ecryptfs_set_dentry_private(dentry, dentry_info);
337 if (!dentry_info) {
338 printk(KERN_ERR "%s: Out of memory whilst attempting "
339 "to allocate ecryptfs_dentry_info struct\n",
340 __func__);
341 dput(lower_dentry);
342 mntput(lower_mnt);
343 d_drop(dentry);
344 return -ENOMEM;
345 }
346 ecryptfs_set_dentry_lower(dentry, lower_dentry);
347 ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
348
349 if (!lower_dentry->d_inode) {
350 /* We want to add because we couldn't find in lower */
351 d_add(dentry, NULL);
352 return 0;
353 }
354 inode = __ecryptfs_get_inode(lower_inode, dir_inode->i_sb);
355 if (IS_ERR(inode)) {
356 printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
357 __func__, PTR_ERR(inode));
358 return PTR_ERR(inode);
359 }
360 if (S_ISREG(inode->i_mode)) {
361 rc = ecryptfs_i_size_read(dentry, inode);
362 if (rc) {
363 make_bad_inode(inode);
364 return rc;
365 }
366 }
367
368 if (inode->i_state & I_NEW)
369 unlock_new_inode(inode);
370 d_add(dentry, inode);
371
372 return rc;
373}
374
375/**
376 * ecryptfs_lookup
377 * @ecryptfs_dir_inode: The eCryptfs directory inode
378 * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
379 * @ecryptfs_nd: nameidata; may be NULL
380 *
381 * Find a file on disk. If the file does not exist, then we'll add it to the
382 * dentry cache and continue on to read it from the disk.
383 */
384static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
385 struct dentry *ecryptfs_dentry,
386 struct nameidata *ecryptfs_nd)
387{
388 char *encrypted_and_encoded_name = NULL;
389 size_t encrypted_and_encoded_name_size;
390 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
391 struct dentry *lower_dir_dentry, *lower_dentry;
392 int rc = 0;
393
394 if ((ecryptfs_dentry->d_name.len == 1
395 && !strcmp(ecryptfs_dentry->d_name.name, "."))
396 || (ecryptfs_dentry->d_name.len == 2
397 && !strcmp(ecryptfs_dentry->d_name.name, ".."))) {
398 goto out_d_drop;
399 }
400 lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
401 mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
402 lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name,
403 lower_dir_dentry,
404 ecryptfs_dentry->d_name.len);
405 mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
406 if (IS_ERR(lower_dentry)) {
407 rc = PTR_ERR(lower_dentry);
408 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
409 "[%d] on lower_dentry = [%s]\n", __func__, rc,
410 encrypted_and_encoded_name);
411 goto out_d_drop;
412 }
413 if (lower_dentry->d_inode)
414 goto interpose;
415 mount_crypt_stat = &ecryptfs_superblock_to_private(
416 ecryptfs_dentry->d_sb)->mount_crypt_stat;
417 if (!(mount_crypt_stat
418 && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)))
419 goto interpose;
420 dput(lower_dentry);
421 rc = ecryptfs_encrypt_and_encode_filename(
422 &encrypted_and_encoded_name, &encrypted_and_encoded_name_size,
423 NULL, mount_crypt_stat, ecryptfs_dentry->d_name.name,
424 ecryptfs_dentry->d_name.len);
425 if (rc) {
426 printk(KERN_ERR "%s: Error attempting to encrypt and encode "
427 "filename; rc = [%d]\n", __func__, rc);
428 goto out_d_drop;
429 }
430 mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
431 lower_dentry = lookup_one_len(encrypted_and_encoded_name,
432 lower_dir_dentry,
433 encrypted_and_encoded_name_size);
434 mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
435 if (IS_ERR(lower_dentry)) {
436 rc = PTR_ERR(lower_dentry);
437 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
438 "[%d] on lower_dentry = [%s]\n", __func__, rc,
439 encrypted_and_encoded_name);
440 goto out_d_drop;
441 }
442interpose:
443 rc = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry,
444 ecryptfs_dir_inode);
445 goto out;
446out_d_drop:
447 d_drop(ecryptfs_dentry);
448out:
449 kfree(encrypted_and_encoded_name);
450 return ERR_PTR(rc);
451}
452
453static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
454 struct dentry *new_dentry)
455{
456 struct dentry *lower_old_dentry;
457 struct dentry *lower_new_dentry;
458 struct dentry *lower_dir_dentry;
459 u64 file_size_save;
460 int rc;
461
462 file_size_save = i_size_read(old_dentry->d_inode);
463 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
464 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
465 dget(lower_old_dentry);
466 dget(lower_new_dentry);
467 lower_dir_dentry = lock_parent(lower_new_dentry);
468 rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
469 lower_new_dentry);
470 if (rc || !lower_new_dentry->d_inode)
471 goto out_lock;
472 rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
473 if (rc)
474 goto out_lock;
475 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
476 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
477 old_dentry->d_inode->i_nlink =
478 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
479 i_size_write(new_dentry->d_inode, file_size_save);
480out_lock:
481 unlock_dir(lower_dir_dentry);
482 dput(lower_new_dentry);
483 dput(lower_old_dentry);
484 return rc;
485}
486
487static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
488{
489 int rc = 0;
490 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
491 struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
492 struct dentry *lower_dir_dentry;
493
494 dget(lower_dentry);
495 lower_dir_dentry = lock_parent(lower_dentry);
496 rc = vfs_unlink(lower_dir_inode, lower_dentry);
497 if (rc) {
498 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
499 goto out_unlock;
500 }
501 fsstack_copy_attr_times(dir, lower_dir_inode);
502 dentry->d_inode->i_nlink =
503 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
504 dentry->d_inode->i_ctime = dir->i_ctime;
505 d_drop(dentry);
506out_unlock:
507 unlock_dir(lower_dir_dentry);
508 dput(lower_dentry);
509 return rc;
510}
511
512static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
513 const char *symname)
514{
515 int rc;
516 struct dentry *lower_dentry;
517 struct dentry *lower_dir_dentry;
518 char *encoded_symname;
519 size_t encoded_symlen;
520 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
521
522 lower_dentry = ecryptfs_dentry_to_lower(dentry);
523 dget(lower_dentry);
524 lower_dir_dentry = lock_parent(lower_dentry);
525 mount_crypt_stat = &ecryptfs_superblock_to_private(
526 dir->i_sb)->mount_crypt_stat;
527 rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
528 &encoded_symlen,
529 NULL,
530 mount_crypt_stat, symname,
531 strlen(symname));
532 if (rc)
533 goto out_lock;
534 rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
535 encoded_symname);
536 kfree(encoded_symname);
537 if (rc || !lower_dentry->d_inode)
538 goto out_lock;
539 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
540 if (rc)
541 goto out_lock;
542 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
543 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
544out_lock:
545 unlock_dir(lower_dir_dentry);
546 dput(lower_dentry);
547 if (!dentry->d_inode)
548 d_drop(dentry);
549 return rc;
550}
551
552static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
553{
554 int rc;
555 struct dentry *lower_dentry;
556 struct dentry *lower_dir_dentry;
557
558 lower_dentry = ecryptfs_dentry_to_lower(dentry);
559 lower_dir_dentry = lock_parent(lower_dentry);
560 rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
561 if (rc || !lower_dentry->d_inode)
562 goto out;
563 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
564 if (rc)
565 goto out;
566 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
567 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
568 dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
569out:
570 unlock_dir(lower_dir_dentry);
571 if (!dentry->d_inode)
572 d_drop(dentry);
573 return rc;
574}
575
576static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
577{
578 struct dentry *lower_dentry;
579 struct dentry *lower_dir_dentry;
580 int rc;
581
582 lower_dentry = ecryptfs_dentry_to_lower(dentry);
583 dget(dentry);
584 lower_dir_dentry = lock_parent(lower_dentry);
585 dget(lower_dentry);
586 rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
587 dput(lower_dentry);
588 if (!rc && dentry->d_inode)
589 clear_nlink(dentry->d_inode);
590 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
591 dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
592 unlock_dir(lower_dir_dentry);
593 if (!rc)
594 d_drop(dentry);
595 dput(dentry);
596 return rc;
597}
598
599static int
600ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
601{
602 int rc;
603 struct dentry *lower_dentry;
604 struct dentry *lower_dir_dentry;
605
606 lower_dentry = ecryptfs_dentry_to_lower(dentry);
607 lower_dir_dentry = lock_parent(lower_dentry);
608 rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
609 if (rc || !lower_dentry->d_inode)
610 goto out;
611 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
612 if (rc)
613 goto out;
614 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
615 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
616out:
617 unlock_dir(lower_dir_dentry);
618 if (!dentry->d_inode)
619 d_drop(dentry);
620 return rc;
621}
622
623static int
624ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
625 struct inode *new_dir, struct dentry *new_dentry)
626{
627 int rc;
628 struct dentry *lower_old_dentry;
629 struct dentry *lower_new_dentry;
630 struct dentry *lower_old_dir_dentry;
631 struct dentry *lower_new_dir_dentry;
632 struct dentry *trap = NULL;
633
634 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
635 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
636 dget(lower_old_dentry);
637 dget(lower_new_dentry);
638 lower_old_dir_dentry = dget_parent(lower_old_dentry);
639 lower_new_dir_dentry = dget_parent(lower_new_dentry);
640 trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
641 /* source should not be ancestor of target */
642 if (trap == lower_old_dentry) {
643 rc = -EINVAL;
644 goto out_lock;
645 }
646 /* target should not be ancestor of source */
647 if (trap == lower_new_dentry) {
648 rc = -ENOTEMPTY;
649 goto out_lock;
650 }
651 rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
652 lower_new_dir_dentry->d_inode, lower_new_dentry);
653 if (rc)
654 goto out_lock;
655 fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode);
656 if (new_dir != old_dir)
657 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode);
658out_lock:
659 unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
660 dput(lower_new_dir_dentry);
661 dput(lower_old_dir_dentry);
662 dput(lower_new_dentry);
663 dput(lower_old_dentry);
664 return rc;
665}
666
667static int ecryptfs_readlink_lower(struct dentry *dentry, char **buf,
668 size_t *bufsiz)
669{
670 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
671 char *lower_buf;
672 size_t lower_bufsiz = PATH_MAX;
673 mm_segment_t old_fs;
674 int rc;
675
676 lower_buf = kmalloc(lower_bufsiz, GFP_KERNEL);
677 if (!lower_buf) {
678 rc = -ENOMEM;
679 goto out;
680 }
681 old_fs = get_fs();
682 set_fs(get_ds());
683 rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
684 (char __user *)lower_buf,
685 lower_bufsiz);
686 set_fs(old_fs);
687 if (rc < 0)
688 goto out;
689 lower_bufsiz = rc;
690 rc = ecryptfs_decode_and_decrypt_filename(buf, bufsiz, dentry,
691 lower_buf, lower_bufsiz);
692out:
693 kfree(lower_buf);
694 return rc;
695}
696
697static int
698ecryptfs_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
699{
700 char *kbuf;
701 size_t kbufsiz, copied;
702 int rc;
703
704 rc = ecryptfs_readlink_lower(dentry, &kbuf, &kbufsiz);
705 if (rc)
706 goto out;
707 copied = min_t(size_t, bufsiz, kbufsiz);
708 rc = copy_to_user(buf, kbuf, copied) ? -EFAULT : copied;
709 kfree(kbuf);
710 fsstack_copy_attr_atime(dentry->d_inode,
711 ecryptfs_dentry_to_lower(dentry)->d_inode);
712out:
713 return rc;
714}
715
716static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
717{
718 char *buf;
719 int len = PAGE_SIZE, rc;
720 mm_segment_t old_fs;
721
722 /* Released in ecryptfs_put_link(); only release here on error */
723 buf = kmalloc(len, GFP_KERNEL);
724 if (!buf) {
725 buf = ERR_PTR(-ENOMEM);
726 goto out;
727 }
728 old_fs = get_fs();
729 set_fs(get_ds());
730 rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
731 set_fs(old_fs);
732 if (rc < 0) {
733 kfree(buf);
734 buf = ERR_PTR(rc);
735 } else
736 buf[rc] = '\0';
737out:
738 nd_set_link(nd, buf);
739 return NULL;
740}
741
742static void
743ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
744{
745 char *buf = nd_get_link(nd);
746 if (!IS_ERR(buf)) {
747 /* Free the char* */
748 kfree(buf);
749 }
750}
751
752/**
753 * upper_size_to_lower_size
754 * @crypt_stat: Crypt_stat associated with file
755 * @upper_size: Size of the upper file
756 *
757 * Calculate the required size of the lower file based on the
758 * specified size of the upper file. This calculation is based on the
759 * number of headers in the underlying file and the extent size.
760 *
761 * Returns Calculated size of the lower file.
762 */
763static loff_t
764upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
765 loff_t upper_size)
766{
767 loff_t lower_size;
768
769 lower_size = ecryptfs_lower_header_size(crypt_stat);
770 if (upper_size != 0) {
771 loff_t num_extents;
772
773 num_extents = upper_size >> crypt_stat->extent_shift;
774 if (upper_size & ~crypt_stat->extent_mask)
775 num_extents++;
776 lower_size += (num_extents * crypt_stat->extent_size);
777 }
778 return lower_size;
779}
780
781/**
782 * truncate_upper
783 * @dentry: The ecryptfs layer dentry
784 * @ia: Address of the ecryptfs inode's attributes
785 * @lower_ia: Address of the lower inode's attributes
786 *
787 * Function to handle truncations modifying the size of the file. Note
788 * that the file sizes are interpolated. When expanding, we are simply
789 * writing strings of 0's out. When truncating, we truncate the upper
790 * inode and update the lower_ia according to the page index
791 * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
792 * the caller must use lower_ia in a call to notify_change() to perform
793 * the truncation of the lower inode.
794 *
795 * Returns zero on success; non-zero otherwise
796 */
797static int truncate_upper(struct dentry *dentry, struct iattr *ia,
798 struct iattr *lower_ia)
799{
800 int rc = 0;
801 struct inode *inode = dentry->d_inode;
802 struct ecryptfs_crypt_stat *crypt_stat;
803 loff_t i_size = i_size_read(inode);
804 loff_t lower_size_before_truncate;
805 loff_t lower_size_after_truncate;
806
807 if (unlikely((ia->ia_size == i_size))) {
808 lower_ia->ia_valid &= ~ATTR_SIZE;
809 return 0;
810 }
811 rc = ecryptfs_get_lower_file(dentry, inode);
812 if (rc)
813 return rc;
814 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
815 /* Switch on growing or shrinking file */
816 if (ia->ia_size > i_size) {
817 char zero[] = { 0x00 };
818
819 lower_ia->ia_valid &= ~ATTR_SIZE;
820 /* Write a single 0 at the last position of the file;
821 * this triggers code that will fill in 0's throughout
822 * the intermediate portion of the previous end of the
823 * file and the new and of the file */
824 rc = ecryptfs_write(inode, zero,
825 (ia->ia_size - 1), 1);
826 } else { /* ia->ia_size < i_size_read(inode) */
827 /* We're chopping off all the pages down to the page
828 * in which ia->ia_size is located. Fill in the end of
829 * that page from (ia->ia_size & ~PAGE_CACHE_MASK) to
830 * PAGE_CACHE_SIZE with zeros. */
831 size_t num_zeros = (PAGE_CACHE_SIZE
832 - (ia->ia_size & ~PAGE_CACHE_MASK));
833
834
835 /*
836 * XXX(truncate) this should really happen at the begginning
837 * of ->setattr. But the code is too messy to that as part
838 * of a larger patch. ecryptfs is also totally missing out
839 * on the inode_change_ok check at the beginning of
840 * ->setattr while would include this.
841 */
842 rc = inode_newsize_ok(inode, ia->ia_size);
843 if (rc)
844 goto out;
845
846 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
847 truncate_setsize(inode, ia->ia_size);
848 lower_ia->ia_size = ia->ia_size;
849 lower_ia->ia_valid |= ATTR_SIZE;
850 goto out;
851 }
852 if (num_zeros) {
853 char *zeros_virt;
854
855 zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
856 if (!zeros_virt) {
857 rc = -ENOMEM;
858 goto out;
859 }
860 rc = ecryptfs_write(inode, zeros_virt,
861 ia->ia_size, num_zeros);
862 kfree(zeros_virt);
863 if (rc) {
864 printk(KERN_ERR "Error attempting to zero out "
865 "the remainder of the end page on "
866 "reducing truncate; rc = [%d]\n", rc);
867 goto out;
868 }
869 }
870 truncate_setsize(inode, ia->ia_size);
871 rc = ecryptfs_write_inode_size_to_metadata(inode);
872 if (rc) {
873 printk(KERN_ERR "Problem with "
874 "ecryptfs_write_inode_size_to_metadata; "
875 "rc = [%d]\n", rc);
876 goto out;
877 }
878 /* We are reducing the size of the ecryptfs file, and need to
879 * know if we need to reduce the size of the lower file. */
880 lower_size_before_truncate =
881 upper_size_to_lower_size(crypt_stat, i_size);
882 lower_size_after_truncate =
883 upper_size_to_lower_size(crypt_stat, ia->ia_size);
884 if (lower_size_after_truncate < lower_size_before_truncate) {
885 lower_ia->ia_size = lower_size_after_truncate;
886 lower_ia->ia_valid |= ATTR_SIZE;
887 } else
888 lower_ia->ia_valid &= ~ATTR_SIZE;
889 }
890out:
891 ecryptfs_put_lower_file(inode);
892 return rc;
893}
894
895/**
896 * ecryptfs_truncate
897 * @dentry: The ecryptfs layer dentry
898 * @new_length: The length to expand the file to
899 *
900 * Simple function that handles the truncation of an eCryptfs inode and
901 * its corresponding lower inode.
902 *
903 * Returns zero on success; non-zero otherwise
904 */
905int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
906{
907 struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
908 struct iattr lower_ia = { .ia_valid = 0 };
909 int rc;
910
911 rc = truncate_upper(dentry, &ia, &lower_ia);
912 if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
913 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
914
915 mutex_lock(&lower_dentry->d_inode->i_mutex);
916 rc = notify_change(lower_dentry, &lower_ia);
917 mutex_unlock(&lower_dentry->d_inode->i_mutex);
918 }
919 return rc;
920}
921
922static int
923ecryptfs_permission(struct inode *inode, int mask)
924{
925 return inode_permission(ecryptfs_inode_to_lower(inode), mask);
926}
927
928/**
929 * ecryptfs_setattr
930 * @dentry: dentry handle to the inode to modify
931 * @ia: Structure with flags of what to change and values
932 *
933 * Updates the metadata of an inode. If the update is to the size
934 * i.e. truncation, then ecryptfs_truncate will handle the size modification
935 * of both the ecryptfs inode and the lower inode.
936 *
937 * All other metadata changes will be passed right to the lower filesystem,
938 * and we will just update our inode to look like the lower.
939 */
940static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
941{
942 int rc = 0;
943 struct dentry *lower_dentry;
944 struct iattr lower_ia;
945 struct inode *inode;
946 struct inode *lower_inode;
947 struct ecryptfs_crypt_stat *crypt_stat;
948
949 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
950 if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
951 ecryptfs_init_crypt_stat(crypt_stat);
952 inode = dentry->d_inode;
953 lower_inode = ecryptfs_inode_to_lower(inode);
954 lower_dentry = ecryptfs_dentry_to_lower(dentry);
955 mutex_lock(&crypt_stat->cs_mutex);
956 if (S_ISDIR(dentry->d_inode->i_mode))
957 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
958 else if (S_ISREG(dentry->d_inode->i_mode)
959 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
960 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
961 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
962
963 mount_crypt_stat = &ecryptfs_superblock_to_private(
964 dentry->d_sb)->mount_crypt_stat;
965 rc = ecryptfs_get_lower_file(dentry, inode);
966 if (rc) {
967 mutex_unlock(&crypt_stat->cs_mutex);
968 goto out;
969 }
970 rc = ecryptfs_read_metadata(dentry);
971 ecryptfs_put_lower_file(inode);
972 if (rc) {
973 if (!(mount_crypt_stat->flags
974 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
975 rc = -EIO;
976 printk(KERN_WARNING "Either the lower file "
977 "is not in a valid eCryptfs format, "
978 "or the key could not be retrieved. "
979 "Plaintext passthrough mode is not "
980 "enabled; returning -EIO\n");
981 mutex_unlock(&crypt_stat->cs_mutex);
982 goto out;
983 }
984 rc = 0;
985 crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
986 | ECRYPTFS_ENCRYPTED);
987 }
988 }
989 mutex_unlock(&crypt_stat->cs_mutex);
990 if (S_ISREG(inode->i_mode)) {
991 rc = filemap_write_and_wait(inode->i_mapping);
992 if (rc)
993 goto out;
994 fsstack_copy_attr_all(inode, lower_inode);
995 }
996 memcpy(&lower_ia, ia, sizeof(lower_ia));
997 if (ia->ia_valid & ATTR_FILE)
998 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
999 if (ia->ia_valid & ATTR_SIZE) {
1000 rc = truncate_upper(dentry, ia, &lower_ia);
1001 if (rc < 0)
1002 goto out;
1003 }
1004
1005 /*
1006 * mode change is for clearing setuid/setgid bits. Allow lower fs
1007 * to interpret this in its own way.
1008 */
1009 if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
1010 lower_ia.ia_valid &= ~ATTR_MODE;
1011
1012 mutex_lock(&lower_dentry->d_inode->i_mutex);
1013 rc = notify_change(lower_dentry, &lower_ia);
1014 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1015out:
1016 fsstack_copy_attr_all(inode, lower_inode);
1017 return rc;
1018}
1019
1020int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
1021 struct kstat *stat)
1022{
1023 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
1024 int rc = 0;
1025
1026 mount_crypt_stat = &ecryptfs_superblock_to_private(
1027 dentry->d_sb)->mount_crypt_stat;
1028 generic_fillattr(dentry->d_inode, stat);
1029 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
1030 char *target;
1031 size_t targetsiz;
1032
1033 rc = ecryptfs_readlink_lower(dentry, &target, &targetsiz);
1034 if (!rc) {
1035 kfree(target);
1036 stat->size = targetsiz;
1037 }
1038 }
1039 return rc;
1040}
1041
1042int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
1043 struct kstat *stat)
1044{
1045 struct kstat lower_stat;
1046 int rc;
1047
1048 rc = vfs_getattr(ecryptfs_dentry_to_lower_mnt(dentry),
1049 ecryptfs_dentry_to_lower(dentry), &lower_stat);
1050 if (!rc) {
1051 fsstack_copy_attr_all(dentry->d_inode,
1052 ecryptfs_inode_to_lower(dentry->d_inode));
1053 generic_fillattr(dentry->d_inode, stat);
1054 stat->blocks = lower_stat.blocks;
1055 }
1056 return rc;
1057}
1058
1059int
1060ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
1061 size_t size, int flags)
1062{
1063 int rc = 0;
1064 struct dentry *lower_dentry;
1065
1066 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1067 if (!lower_dentry->d_inode->i_op->setxattr) {
1068 rc = -EOPNOTSUPP;
1069 goto out;
1070 }
1071
1072 rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1073out:
1074 return rc;
1075}
1076
1077ssize_t
1078ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
1079 void *value, size_t size)
1080{
1081 int rc = 0;
1082
1083 if (!lower_dentry->d_inode->i_op->getxattr) {
1084 rc = -EOPNOTSUPP;
1085 goto out;
1086 }
1087 mutex_lock(&lower_dentry->d_inode->i_mutex);
1088 rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
1089 size);
1090 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1091out:
1092 return rc;
1093}
1094
1095static ssize_t
1096ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
1097 size_t size)
1098{
1099 return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
1100 value, size);
1101}
1102
1103static ssize_t
1104ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1105{
1106 int rc = 0;
1107 struct dentry *lower_dentry;
1108
1109 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1110 if (!lower_dentry->d_inode->i_op->listxattr) {
1111 rc = -EOPNOTSUPP;
1112 goto out;
1113 }
1114 mutex_lock(&lower_dentry->d_inode->i_mutex);
1115 rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1116 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1117out:
1118 return rc;
1119}
1120
1121static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1122{
1123 int rc = 0;
1124 struct dentry *lower_dentry;
1125
1126 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1127 if (!lower_dentry->d_inode->i_op->removexattr) {
1128 rc = -EOPNOTSUPP;
1129 goto out;
1130 }
1131 mutex_lock(&lower_dentry->d_inode->i_mutex);
1132 rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1133 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1134out:
1135 return rc;
1136}
1137
1138const struct inode_operations ecryptfs_symlink_iops = {
1139 .readlink = ecryptfs_readlink,
1140 .follow_link = ecryptfs_follow_link,
1141 .put_link = ecryptfs_put_link,
1142 .permission = ecryptfs_permission,
1143 .setattr = ecryptfs_setattr,
1144 .getattr = ecryptfs_getattr_link,
1145 .setxattr = ecryptfs_setxattr,
1146 .getxattr = ecryptfs_getxattr,
1147 .listxattr = ecryptfs_listxattr,
1148 .removexattr = ecryptfs_removexattr
1149};
1150
1151const struct inode_operations ecryptfs_dir_iops = {
1152 .create = ecryptfs_create,
1153 .lookup = ecryptfs_lookup,
1154 .link = ecryptfs_link,
1155 .unlink = ecryptfs_unlink,
1156 .symlink = ecryptfs_symlink,
1157 .mkdir = ecryptfs_mkdir,
1158 .rmdir = ecryptfs_rmdir,
1159 .mknod = ecryptfs_mknod,
1160 .rename = ecryptfs_rename,
1161 .permission = ecryptfs_permission,
1162 .setattr = ecryptfs_setattr,
1163 .setxattr = ecryptfs_setxattr,
1164 .getxattr = ecryptfs_getxattr,
1165 .listxattr = ecryptfs_listxattr,
1166 .removexattr = ecryptfs_removexattr
1167};
1168
1169const struct inode_operations ecryptfs_main_iops = {
1170 .permission = ecryptfs_permission,
1171 .setattr = ecryptfs_setattr,
1172 .getattr = ecryptfs_getattr,
1173 .setxattr = ecryptfs_setxattr,
1174 .getxattr = ecryptfs_getxattr,
1175 .listxattr = ecryptfs_listxattr,
1176 .removexattr = ecryptfs_removexattr
1177};
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};