2 * eCryptfs: Linux filesystem encryption layer
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>
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.
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.
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
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"
39 static struct dentry *lock_parent(struct dentry *dentry)
43 dir = dget_parent(dentry);
44 mutex_lock_nested(&(d_inode(dir)->i_mutex), I_MUTEX_PARENT);
48 static void unlock_dir(struct dentry *dir)
50 mutex_unlock(&d_inode(dir)->i_mutex);
54 static int ecryptfs_inode_test(struct inode *inode, void *lower_inode)
56 return ecryptfs_inode_to_lower(inode) == lower_inode;
59 static int ecryptfs_inode_set(struct inode *inode, void *opaque)
61 struct inode *lower_inode = opaque;
63 ecryptfs_set_inode_lower(inode, lower_inode);
64 fsstack_copy_attr_all(inode, lower_inode);
65 /* i_size will be overwritten for encrypted regular files */
66 fsstack_copy_inode_size(inode, lower_inode);
67 inode->i_ino = lower_inode->i_ino;
69 inode->i_mapping->a_ops = &ecryptfs_aops;
71 if (S_ISLNK(inode->i_mode))
72 inode->i_op = &ecryptfs_symlink_iops;
73 else if (S_ISDIR(inode->i_mode))
74 inode->i_op = &ecryptfs_dir_iops;
76 inode->i_op = &ecryptfs_main_iops;
78 if (S_ISDIR(inode->i_mode))
79 inode->i_fop = &ecryptfs_dir_fops;
80 else if (special_file(inode->i_mode))
81 init_special_inode(inode, inode->i_mode, inode->i_rdev);
83 inode->i_fop = &ecryptfs_main_fops;
88 static struct inode *__ecryptfs_get_inode(struct inode *lower_inode,
89 struct super_block *sb)
93 if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb))
94 return ERR_PTR(-EXDEV);
95 if (!igrab(lower_inode))
96 return ERR_PTR(-ESTALE);
97 inode = iget5_locked(sb, (unsigned long)lower_inode,
98 ecryptfs_inode_test, ecryptfs_inode_set,
102 return ERR_PTR(-EACCES);
104 if (!(inode->i_state & I_NEW))
110 struct inode *ecryptfs_get_inode(struct inode *lower_inode,
111 struct super_block *sb)
113 struct inode *inode = __ecryptfs_get_inode(lower_inode, sb);
115 if (!IS_ERR(inode) && (inode->i_state & I_NEW))
116 unlock_new_inode(inode);
123 * @lower_dentry: Existing dentry in the lower filesystem
124 * @dentry: ecryptfs' dentry
125 * @sb: ecryptfs's super_block
127 * Interposes upper and lower dentries.
129 * Returns zero on success; non-zero otherwise
131 static int ecryptfs_interpose(struct dentry *lower_dentry,
132 struct dentry *dentry, struct super_block *sb)
134 struct inode *inode = ecryptfs_get_inode(d_inode(lower_dentry), sb);
137 return PTR_ERR(inode);
138 d_instantiate(dentry, inode);
143 static int ecryptfs_do_unlink(struct inode *dir, struct dentry *dentry,
146 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
147 struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
148 struct dentry *lower_dir_dentry;
152 lower_dir_dentry = lock_parent(lower_dentry);
153 rc = vfs_unlink(lower_dir_inode, lower_dentry, NULL);
155 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
158 fsstack_copy_attr_times(dir, lower_dir_inode);
159 set_nlink(inode, ecryptfs_inode_to_lower(inode)->i_nlink);
160 inode->i_ctime = dir->i_ctime;
163 unlock_dir(lower_dir_dentry);
170 * @directory_inode: inode of the new file's dentry's parent in ecryptfs
171 * @ecryptfs_dentry: New file's dentry in ecryptfs
172 * @mode: The mode of the new file
174 * Creates the underlying file and the eCryptfs inode which will link to
175 * it. It will also update the eCryptfs directory inode to mimic the
176 * stat of the lower directory inode.
178 * Returns the new eCryptfs inode on success; an ERR_PTR on error condition
180 static struct inode *
181 ecryptfs_do_create(struct inode *directory_inode,
182 struct dentry *ecryptfs_dentry, umode_t mode)
185 struct dentry *lower_dentry;
186 struct dentry *lower_dir_dentry;
189 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
190 lower_dir_dentry = lock_parent(lower_dentry);
191 rc = vfs_create(d_inode(lower_dir_dentry), lower_dentry, mode, true);
193 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
194 "rc = [%d]\n", __func__, rc);
198 inode = __ecryptfs_get_inode(d_inode(lower_dentry),
199 directory_inode->i_sb);
201 vfs_unlink(d_inode(lower_dir_dentry), lower_dentry, NULL);
204 fsstack_copy_attr_times(directory_inode, d_inode(lower_dir_dentry));
205 fsstack_copy_inode_size(directory_inode, d_inode(lower_dir_dentry));
207 unlock_dir(lower_dir_dentry);
212 * ecryptfs_initialize_file
214 * Cause the file to be changed from a basic empty file to an ecryptfs
215 * file with a header and first data page.
217 * Returns zero on success
219 int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry,
220 struct inode *ecryptfs_inode)
222 struct ecryptfs_crypt_stat *crypt_stat =
223 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
226 if (S_ISDIR(ecryptfs_inode->i_mode)) {
227 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
228 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
231 ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
232 rc = ecryptfs_new_file_context(ecryptfs_inode);
234 ecryptfs_printk(KERN_ERR, "Error creating new file "
235 "context; rc = [%d]\n", rc);
238 rc = ecryptfs_get_lower_file(ecryptfs_dentry, ecryptfs_inode);
240 printk(KERN_ERR "%s: Error attempting to initialize "
241 "the lower file for the dentry with name "
242 "[%pd]; rc = [%d]\n", __func__,
243 ecryptfs_dentry, rc);
246 rc = ecryptfs_write_metadata(ecryptfs_dentry, ecryptfs_inode);
248 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
249 ecryptfs_put_lower_file(ecryptfs_inode);
256 * @dir: The inode of the directory in which to create the file.
257 * @dentry: The eCryptfs dentry
258 * @mode: The mode of the new file.
260 * Creates a new file.
262 * Returns zero on success; non-zero on error condition
265 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
266 umode_t mode, bool excl)
268 struct inode *ecryptfs_inode;
271 ecryptfs_inode = ecryptfs_do_create(directory_inode, ecryptfs_dentry,
273 if (IS_ERR(ecryptfs_inode)) {
274 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
275 "lower filesystem\n");
276 rc = PTR_ERR(ecryptfs_inode);
279 /* At this point, a file exists on "disk"; we need to make sure
280 * that this on disk file is prepared to be an ecryptfs file */
281 rc = ecryptfs_initialize_file(ecryptfs_dentry, ecryptfs_inode);
283 ecryptfs_do_unlink(directory_inode, ecryptfs_dentry,
285 make_bad_inode(ecryptfs_inode);
286 unlock_new_inode(ecryptfs_inode);
287 iput(ecryptfs_inode);
290 d_instantiate_new(ecryptfs_dentry, ecryptfs_inode);
295 static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode)
297 struct ecryptfs_crypt_stat *crypt_stat;
300 rc = ecryptfs_get_lower_file(dentry, inode);
302 printk(KERN_ERR "%s: Error attempting to initialize "
303 "the lower file for the dentry with name "
304 "[%pd]; rc = [%d]\n", __func__,
309 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
310 /* TODO: lock for crypt_stat comparison */
311 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
312 ecryptfs_set_default_sizes(crypt_stat);
314 rc = ecryptfs_read_and_validate_header_region(inode);
315 ecryptfs_put_lower_file(inode);
317 rc = ecryptfs_read_and_validate_xattr_region(dentry, inode);
319 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
322 /* Must return 0 to allow non-eCryptfs files to be looked up, too */
327 * ecryptfs_lookup_interpose - Dentry interposition for a lookup
329 static int ecryptfs_lookup_interpose(struct dentry *dentry,
330 struct dentry *lower_dentry,
331 struct inode *dir_inode)
333 struct inode *inode, *lower_inode;
334 struct ecryptfs_dentry_info *dentry_info;
335 struct vfsmount *lower_mnt;
338 dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
340 printk(KERN_ERR "%s: Out of memory whilst attempting "
341 "to allocate ecryptfs_dentry_info struct\n",
347 lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
348 fsstack_copy_attr_atime(dir_inode, d_inode(lower_dentry->d_parent));
349 BUG_ON(!d_count(lower_dentry));
351 ecryptfs_set_dentry_private(dentry, dentry_info);
352 dentry_info->lower_path.mnt = lower_mnt;
353 dentry_info->lower_path.dentry = lower_dentry;
356 * negative dentry can go positive under us here - its parent is not
357 * locked. That's OK and that could happen just as we return from
358 * ecryptfs_lookup() anyway. Just need to be careful and fetch
359 * ->d_inode only once - it's not stable here.
361 lower_inode = READ_ONCE(lower_dentry->d_inode);
364 /* We want to add because we couldn't find in lower */
368 inode = __ecryptfs_get_inode(lower_inode, dir_inode->i_sb);
370 printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
371 __func__, PTR_ERR(inode));
372 return PTR_ERR(inode);
374 if (S_ISREG(inode->i_mode)) {
375 rc = ecryptfs_i_size_read(dentry, inode);
377 make_bad_inode(inode);
382 if (inode->i_state & I_NEW)
383 unlock_new_inode(inode);
384 d_add(dentry, inode);
391 * @ecryptfs_dir_inode: The eCryptfs directory inode
392 * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
393 * @flags: lookup flags
395 * Find a file on disk. If the file does not exist, then we'll add it to the
396 * dentry cache and continue on to read it from the disk.
398 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
399 struct dentry *ecryptfs_dentry,
402 char *encrypted_and_encoded_name = NULL;
403 size_t encrypted_and_encoded_name_size;
404 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
405 struct dentry *lower_dir_dentry, *lower_dentry;
408 lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
409 mutex_lock(&d_inode(lower_dir_dentry)->i_mutex);
410 lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name,
412 ecryptfs_dentry->d_name.len);
413 mutex_unlock(&d_inode(lower_dir_dentry)->i_mutex);
414 if (IS_ERR(lower_dentry)) {
415 rc = PTR_ERR(lower_dentry);
416 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
417 "[%d] on lower_dentry = [%pd]\n", __func__, rc,
421 if (d_really_is_positive(lower_dentry))
423 mount_crypt_stat = &ecryptfs_superblock_to_private(
424 ecryptfs_dentry->d_sb)->mount_crypt_stat;
425 if (!(mount_crypt_stat
426 && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)))
429 rc = ecryptfs_encrypt_and_encode_filename(
430 &encrypted_and_encoded_name, &encrypted_and_encoded_name_size,
431 NULL, mount_crypt_stat, ecryptfs_dentry->d_name.name,
432 ecryptfs_dentry->d_name.len);
434 printk(KERN_ERR "%s: Error attempting to encrypt and encode "
435 "filename; rc = [%d]\n", __func__, rc);
438 mutex_lock(&d_inode(lower_dir_dentry)->i_mutex);
439 lower_dentry = lookup_one_len(encrypted_and_encoded_name,
441 encrypted_and_encoded_name_size);
442 mutex_unlock(&d_inode(lower_dir_dentry)->i_mutex);
443 if (IS_ERR(lower_dentry)) {
444 rc = PTR_ERR(lower_dentry);
445 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
446 "[%d] on lower_dentry = [%s]\n", __func__, rc,
447 encrypted_and_encoded_name);
451 rc = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry,
454 kfree(encrypted_and_encoded_name);
458 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
459 struct dentry *new_dentry)
461 struct dentry *lower_old_dentry;
462 struct dentry *lower_new_dentry;
463 struct dentry *lower_dir_dentry;
467 file_size_save = i_size_read(d_inode(old_dentry));
468 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
469 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
470 dget(lower_old_dentry);
471 dget(lower_new_dentry);
472 lower_dir_dentry = lock_parent(lower_new_dentry);
473 rc = vfs_link(lower_old_dentry, d_inode(lower_dir_dentry),
474 lower_new_dentry, NULL);
475 if (rc || d_really_is_negative(lower_new_dentry))
477 rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
480 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
481 fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
482 set_nlink(d_inode(old_dentry),
483 ecryptfs_inode_to_lower(d_inode(old_dentry))->i_nlink);
484 i_size_write(d_inode(new_dentry), file_size_save);
486 unlock_dir(lower_dir_dentry);
487 dput(lower_new_dentry);
488 dput(lower_old_dentry);
492 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
494 return ecryptfs_do_unlink(dir, dentry, d_inode(dentry));
497 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
501 struct dentry *lower_dentry;
502 struct dentry *lower_dir_dentry;
503 char *encoded_symname;
504 size_t encoded_symlen;
505 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
507 lower_dentry = ecryptfs_dentry_to_lower(dentry);
509 lower_dir_dentry = lock_parent(lower_dentry);
510 mount_crypt_stat = &ecryptfs_superblock_to_private(
511 dir->i_sb)->mount_crypt_stat;
512 rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
515 mount_crypt_stat, symname,
519 rc = vfs_symlink(d_inode(lower_dir_dentry), lower_dentry,
521 kfree(encoded_symname);
522 if (rc || d_really_is_negative(lower_dentry))
524 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
527 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
528 fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
530 unlock_dir(lower_dir_dentry);
532 if (d_really_is_negative(dentry))
537 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
540 struct dentry *lower_dentry;
541 struct dentry *lower_dir_dentry;
543 lower_dentry = ecryptfs_dentry_to_lower(dentry);
544 lower_dir_dentry = lock_parent(lower_dentry);
545 rc = vfs_mkdir(d_inode(lower_dir_dentry), lower_dentry, mode);
546 if (rc || d_really_is_negative(lower_dentry))
548 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
551 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
552 fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
553 set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
555 unlock_dir(lower_dir_dentry);
556 if (d_really_is_negative(dentry))
561 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
563 struct dentry *lower_dentry;
564 struct dentry *lower_dir_dentry;
567 lower_dentry = ecryptfs_dentry_to_lower(dentry);
569 lower_dir_dentry = lock_parent(lower_dentry);
571 rc = vfs_rmdir(d_inode(lower_dir_dentry), lower_dentry);
573 if (!rc && d_really_is_positive(dentry))
574 clear_nlink(d_inode(dentry));
575 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
576 set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
577 unlock_dir(lower_dir_dentry);
585 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
588 struct dentry *lower_dentry;
589 struct dentry *lower_dir_dentry;
591 lower_dentry = ecryptfs_dentry_to_lower(dentry);
592 lower_dir_dentry = lock_parent(lower_dentry);
593 rc = vfs_mknod(d_inode(lower_dir_dentry), lower_dentry, mode, dev);
594 if (rc || d_really_is_negative(lower_dentry))
596 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
599 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
600 fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
602 unlock_dir(lower_dir_dentry);
603 if (d_really_is_negative(dentry))
609 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
610 struct inode *new_dir, struct dentry *new_dentry)
613 struct dentry *lower_old_dentry;
614 struct dentry *lower_new_dentry;
615 struct dentry *lower_old_dir_dentry;
616 struct dentry *lower_new_dir_dentry;
617 struct dentry *trap = NULL;
618 struct inode *target_inode;
620 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
621 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
622 dget(lower_old_dentry);
623 dget(lower_new_dentry);
624 lower_old_dir_dentry = dget_parent(lower_old_dentry);
625 lower_new_dir_dentry = dget_parent(lower_new_dentry);
626 target_inode = d_inode(new_dentry);
627 trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
628 /* source should not be ancestor of target */
629 if (trap == lower_old_dentry) {
633 /* target should not be ancestor of source */
634 if (trap == lower_new_dentry) {
638 rc = vfs_rename(d_inode(lower_old_dir_dentry), lower_old_dentry,
639 d_inode(lower_new_dir_dentry), lower_new_dentry,
644 fsstack_copy_attr_all(target_inode,
645 ecryptfs_inode_to_lower(target_inode));
646 fsstack_copy_attr_all(new_dir, d_inode(lower_new_dir_dentry));
647 if (new_dir != old_dir)
648 fsstack_copy_attr_all(old_dir, d_inode(lower_old_dir_dentry));
650 unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
651 dput(lower_new_dir_dentry);
652 dput(lower_old_dir_dentry);
653 dput(lower_new_dentry);
654 dput(lower_old_dentry);
658 static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
660 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
666 lower_buf = kmalloc(PATH_MAX, GFP_KERNEL);
668 return ERR_PTR(-ENOMEM);
671 rc = d_inode(lower_dentry)->i_op->readlink(lower_dentry,
672 (char __user *)lower_buf,
677 rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb,
681 return rc ? ERR_PTR(rc) : buf;
684 static const char *ecryptfs_follow_link(struct dentry *dentry, void **cookie)
687 char *buf = ecryptfs_readlink_lower(dentry, &len);
690 fsstack_copy_attr_atime(d_inode(dentry),
691 d_inode(ecryptfs_dentry_to_lower(dentry)));
693 return *cookie = buf;
697 * upper_size_to_lower_size
698 * @crypt_stat: Crypt_stat associated with file
699 * @upper_size: Size of the upper file
701 * Calculate the required size of the lower file based on the
702 * specified size of the upper file. This calculation is based on the
703 * number of headers in the underlying file and the extent size.
705 * Returns Calculated size of the lower file.
708 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
713 lower_size = ecryptfs_lower_header_size(crypt_stat);
714 if (upper_size != 0) {
717 num_extents = upper_size >> crypt_stat->extent_shift;
718 if (upper_size & ~crypt_stat->extent_mask)
720 lower_size += (num_extents * crypt_stat->extent_size);
727 * @dentry: The ecryptfs layer dentry
728 * @ia: Address of the ecryptfs inode's attributes
729 * @lower_ia: Address of the lower inode's attributes
731 * Function to handle truncations modifying the size of the file. Note
732 * that the file sizes are interpolated. When expanding, we are simply
733 * writing strings of 0's out. When truncating, we truncate the upper
734 * inode and update the lower_ia according to the page index
735 * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
736 * the caller must use lower_ia in a call to notify_change() to perform
737 * the truncation of the lower inode.
739 * Returns zero on success; non-zero otherwise
741 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
742 struct iattr *lower_ia)
745 struct inode *inode = d_inode(dentry);
746 struct ecryptfs_crypt_stat *crypt_stat;
747 loff_t i_size = i_size_read(inode);
748 loff_t lower_size_before_truncate;
749 loff_t lower_size_after_truncate;
751 if (unlikely((ia->ia_size == i_size))) {
752 lower_ia->ia_valid &= ~ATTR_SIZE;
755 rc = ecryptfs_get_lower_file(dentry, inode);
758 crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
759 /* Switch on growing or shrinking file */
760 if (ia->ia_size > i_size) {
761 char zero[] = { 0x00 };
763 lower_ia->ia_valid &= ~ATTR_SIZE;
764 /* Write a single 0 at the last position of the file;
765 * this triggers code that will fill in 0's throughout
766 * the intermediate portion of the previous end of the
767 * file and the new and of the file */
768 rc = ecryptfs_write(inode, zero,
769 (ia->ia_size - 1), 1);
770 } else { /* ia->ia_size < i_size_read(inode) */
771 /* We're chopping off all the pages down to the page
772 * in which ia->ia_size is located. Fill in the end of
773 * that page from (ia->ia_size & ~PAGE_CACHE_MASK) to
774 * PAGE_CACHE_SIZE with zeros. */
775 size_t num_zeros = (PAGE_CACHE_SIZE
776 - (ia->ia_size & ~PAGE_CACHE_MASK));
778 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
779 truncate_setsize(inode, ia->ia_size);
780 lower_ia->ia_size = ia->ia_size;
781 lower_ia->ia_valid |= ATTR_SIZE;
787 zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
792 rc = ecryptfs_write(inode, zeros_virt,
793 ia->ia_size, num_zeros);
796 printk(KERN_ERR "Error attempting to zero out "
797 "the remainder of the end page on "
798 "reducing truncate; rc = [%d]\n", rc);
802 truncate_setsize(inode, ia->ia_size);
803 rc = ecryptfs_write_inode_size_to_metadata(inode);
805 printk(KERN_ERR "Problem with "
806 "ecryptfs_write_inode_size_to_metadata; "
810 /* We are reducing the size of the ecryptfs file, and need to
811 * know if we need to reduce the size of the lower file. */
812 lower_size_before_truncate =
813 upper_size_to_lower_size(crypt_stat, i_size);
814 lower_size_after_truncate =
815 upper_size_to_lower_size(crypt_stat, ia->ia_size);
816 if (lower_size_after_truncate < lower_size_before_truncate) {
817 lower_ia->ia_size = lower_size_after_truncate;
818 lower_ia->ia_valid |= ATTR_SIZE;
820 lower_ia->ia_valid &= ~ATTR_SIZE;
823 ecryptfs_put_lower_file(inode);
827 static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset)
829 struct ecryptfs_crypt_stat *crypt_stat;
830 loff_t lower_oldsize, lower_newsize;
832 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
833 lower_oldsize = upper_size_to_lower_size(crypt_stat,
835 lower_newsize = upper_size_to_lower_size(crypt_stat, offset);
836 if (lower_newsize > lower_oldsize) {
838 * The eCryptfs inode and the new *lower* size are mixed here
839 * because we may not have the lower i_mutex held and/or it may
840 * not be appropriate to call inode_newsize_ok() with inodes
841 * from other filesystems.
843 return inode_newsize_ok(inode, lower_newsize);
851 * @dentry: The ecryptfs layer dentry
852 * @new_length: The length to expand the file to
854 * Simple function that handles the truncation of an eCryptfs inode and
855 * its corresponding lower inode.
857 * Returns zero on success; non-zero otherwise
859 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
861 struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
862 struct iattr lower_ia = { .ia_valid = 0 };
865 rc = ecryptfs_inode_newsize_ok(d_inode(dentry), new_length);
869 rc = truncate_upper(dentry, &ia, &lower_ia);
870 if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
871 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
873 mutex_lock(&d_inode(lower_dentry)->i_mutex);
874 rc = notify_change(lower_dentry, &lower_ia, NULL);
875 mutex_unlock(&d_inode(lower_dentry)->i_mutex);
881 ecryptfs_permission(struct inode *inode, int mask)
883 return inode_permission(ecryptfs_inode_to_lower(inode), mask);
888 * @dentry: dentry handle to the inode to modify
889 * @ia: Structure with flags of what to change and values
891 * Updates the metadata of an inode. If the update is to the size
892 * i.e. truncation, then ecryptfs_truncate will handle the size modification
893 * of both the ecryptfs inode and the lower inode.
895 * All other metadata changes will be passed right to the lower filesystem,
896 * and we will just update our inode to look like the lower.
898 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
901 struct dentry *lower_dentry;
902 struct iattr lower_ia;
904 struct inode *lower_inode;
905 struct ecryptfs_crypt_stat *crypt_stat;
907 crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
908 if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
909 ecryptfs_init_crypt_stat(crypt_stat);
910 inode = d_inode(dentry);
911 lower_inode = ecryptfs_inode_to_lower(inode);
912 lower_dentry = ecryptfs_dentry_to_lower(dentry);
913 mutex_lock(&crypt_stat->cs_mutex);
914 if (d_is_dir(dentry))
915 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
916 else if (d_is_reg(dentry)
917 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
918 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
919 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
921 mount_crypt_stat = &ecryptfs_superblock_to_private(
922 dentry->d_sb)->mount_crypt_stat;
923 rc = ecryptfs_get_lower_file(dentry, inode);
925 mutex_unlock(&crypt_stat->cs_mutex);
928 rc = ecryptfs_read_metadata(dentry);
929 ecryptfs_put_lower_file(inode);
931 if (!(mount_crypt_stat->flags
932 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
934 printk(KERN_WARNING "Either the lower file "
935 "is not in a valid eCryptfs format, "
936 "or the key could not be retrieved. "
937 "Plaintext passthrough mode is not "
938 "enabled; returning -EIO\n");
939 mutex_unlock(&crypt_stat->cs_mutex);
943 crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
944 | ECRYPTFS_ENCRYPTED);
947 mutex_unlock(&crypt_stat->cs_mutex);
949 rc = inode_change_ok(inode, ia);
952 if (ia->ia_valid & ATTR_SIZE) {
953 rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size);
958 memcpy(&lower_ia, ia, sizeof(lower_ia));
959 if (ia->ia_valid & ATTR_FILE)
960 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
961 if (ia->ia_valid & ATTR_SIZE) {
962 rc = truncate_upper(dentry, ia, &lower_ia);
968 * mode change is for clearing setuid/setgid bits. Allow lower fs
969 * to interpret this in its own way.
971 if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
972 lower_ia.ia_valid &= ~ATTR_MODE;
974 mutex_lock(&d_inode(lower_dentry)->i_mutex);
975 rc = notify_change(lower_dentry, &lower_ia, NULL);
976 mutex_unlock(&d_inode(lower_dentry)->i_mutex);
978 fsstack_copy_attr_all(inode, lower_inode);
982 static int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
985 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
988 mount_crypt_stat = &ecryptfs_superblock_to_private(
989 dentry->d_sb)->mount_crypt_stat;
990 generic_fillattr(d_inode(dentry), stat);
991 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
995 target = ecryptfs_readlink_lower(dentry, &targetsiz);
996 if (!IS_ERR(target)) {
998 stat->size = targetsiz;
1000 rc = PTR_ERR(target);
1006 static int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
1009 struct kstat lower_stat;
1012 rc = vfs_getattr(ecryptfs_dentry_to_lower_path(dentry), &lower_stat);
1014 fsstack_copy_attr_all(d_inode(dentry),
1015 ecryptfs_inode_to_lower(d_inode(dentry)));
1016 generic_fillattr(d_inode(dentry), stat);
1017 stat->blocks = lower_stat.blocks;
1023 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
1024 size_t size, int flags)
1027 struct dentry *lower_dentry;
1029 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1030 if (!d_inode(lower_dentry)->i_op->setxattr) {
1035 rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1036 if (!rc && d_really_is_positive(dentry))
1037 fsstack_copy_attr_all(d_inode(dentry), d_inode(lower_dentry));
1043 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
1044 void *value, size_t size)
1048 if (!d_inode(lower_dentry)->i_op->getxattr) {
1052 mutex_lock(&d_inode(lower_dentry)->i_mutex);
1053 rc = d_inode(lower_dentry)->i_op->getxattr(lower_dentry, name, value,
1055 mutex_unlock(&d_inode(lower_dentry)->i_mutex);
1061 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
1064 return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
1069 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1072 struct dentry *lower_dentry;
1074 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1075 if (!d_inode(lower_dentry)->i_op->listxattr) {
1079 mutex_lock(&d_inode(lower_dentry)->i_mutex);
1080 rc = d_inode(lower_dentry)->i_op->listxattr(lower_dentry, list, size);
1081 mutex_unlock(&d_inode(lower_dentry)->i_mutex);
1086 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1089 struct dentry *lower_dentry;
1091 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1092 if (!d_inode(lower_dentry)->i_op->removexattr) {
1096 mutex_lock(&d_inode(lower_dentry)->i_mutex);
1097 rc = d_inode(lower_dentry)->i_op->removexattr(lower_dentry, name);
1098 mutex_unlock(&d_inode(lower_dentry)->i_mutex);
1103 const struct inode_operations ecryptfs_symlink_iops = {
1104 .readlink = generic_readlink,
1105 .follow_link = ecryptfs_follow_link,
1106 .put_link = kfree_put_link,
1107 .permission = ecryptfs_permission,
1108 .setattr = ecryptfs_setattr,
1109 .getattr = ecryptfs_getattr_link,
1110 .setxattr = ecryptfs_setxattr,
1111 .getxattr = ecryptfs_getxattr,
1112 .listxattr = ecryptfs_listxattr,
1113 .removexattr = ecryptfs_removexattr
1116 const struct inode_operations ecryptfs_dir_iops = {
1117 .create = ecryptfs_create,
1118 .lookup = ecryptfs_lookup,
1119 .link = ecryptfs_link,
1120 .unlink = ecryptfs_unlink,
1121 .symlink = ecryptfs_symlink,
1122 .mkdir = ecryptfs_mkdir,
1123 .rmdir = ecryptfs_rmdir,
1124 .mknod = ecryptfs_mknod,
1125 .rename = ecryptfs_rename,
1126 .permission = ecryptfs_permission,
1127 .setattr = ecryptfs_setattr,
1128 .setxattr = ecryptfs_setxattr,
1129 .getxattr = ecryptfs_getxattr,
1130 .listxattr = ecryptfs_listxattr,
1131 .removexattr = ecryptfs_removexattr
1134 const struct inode_operations ecryptfs_main_iops = {
1135 .permission = ecryptfs_permission,
1136 .setattr = ecryptfs_setattr,
1137 .getattr = ecryptfs_getattr,
1138 .setxattr = ecryptfs_setxattr,
1139 .getxattr = ecryptfs_getxattr,
1140 .listxattr = ecryptfs_listxattr,
1141 .removexattr = ecryptfs_removexattr