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/fs_stack.h>
33 #include <linux/slab.h>
34 #include <linux/xattr.h>
35 #include <asm/unaligned.h>
36 #include "ecryptfs_kernel.h"
38 static struct dentry *lock_parent(struct dentry *dentry)
42 dir = dget_parent(dentry);
43 inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
47 static void unlock_dir(struct dentry *dir)
49 inode_unlock(d_inode(dir));
53 static int ecryptfs_inode_test(struct inode *inode, void *lower_inode)
55 return ecryptfs_inode_to_lower(inode) == lower_inode;
58 static int ecryptfs_inode_set(struct inode *inode, void *opaque)
60 struct inode *lower_inode = opaque;
62 ecryptfs_set_inode_lower(inode, lower_inode);
63 fsstack_copy_attr_all(inode, lower_inode);
64 /* i_size will be overwritten for encrypted regular files */
65 fsstack_copy_inode_size(inode, lower_inode);
66 inode->i_ino = lower_inode->i_ino;
68 inode->i_mapping->a_ops = &ecryptfs_aops;
70 if (S_ISLNK(inode->i_mode))
71 inode->i_op = &ecryptfs_symlink_iops;
72 else if (S_ISDIR(inode->i_mode))
73 inode->i_op = &ecryptfs_dir_iops;
75 inode->i_op = &ecryptfs_main_iops;
77 if (S_ISDIR(inode->i_mode))
78 inode->i_fop = &ecryptfs_dir_fops;
79 else if (special_file(inode->i_mode))
80 init_special_inode(inode, inode->i_mode, inode->i_rdev);
82 inode->i_fop = &ecryptfs_main_fops;
87 static struct inode *__ecryptfs_get_inode(struct inode *lower_inode,
88 struct super_block *sb)
92 if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb))
93 return ERR_PTR(-EXDEV);
94 if (!igrab(lower_inode))
95 return ERR_PTR(-ESTALE);
96 inode = iget5_locked(sb, (unsigned long)lower_inode,
97 ecryptfs_inode_test, ecryptfs_inode_set,
101 return ERR_PTR(-EACCES);
103 if (!(inode->i_state & I_NEW))
109 struct inode *ecryptfs_get_inode(struct inode *lower_inode,
110 struct super_block *sb)
112 struct inode *inode = __ecryptfs_get_inode(lower_inode, sb);
114 if (!IS_ERR(inode) && (inode->i_state & I_NEW))
115 unlock_new_inode(inode);
122 * @lower_dentry: Existing dentry in the lower filesystem
123 * @dentry: ecryptfs' dentry
124 * @sb: ecryptfs's super_block
126 * Interposes upper and lower dentries.
128 * Returns zero on success; non-zero otherwise
130 static int ecryptfs_interpose(struct dentry *lower_dentry,
131 struct dentry *dentry, struct super_block *sb)
133 struct inode *inode = ecryptfs_get_inode(d_inode(lower_dentry), sb);
136 return PTR_ERR(inode);
137 d_instantiate(dentry, inode);
142 static int ecryptfs_do_unlink(struct inode *dir, struct dentry *dentry,
145 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
146 struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
147 struct dentry *lower_dir_dentry;
151 lower_dir_dentry = lock_parent(lower_dentry);
152 rc = vfs_unlink(lower_dir_inode, lower_dentry, NULL);
154 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
157 fsstack_copy_attr_times(dir, lower_dir_inode);
158 set_nlink(inode, ecryptfs_inode_to_lower(inode)->i_nlink);
159 inode->i_ctime = dir->i_ctime;
162 unlock_dir(lower_dir_dentry);
169 * @directory_inode: inode of the new file's dentry's parent in ecryptfs
170 * @ecryptfs_dentry: New file's dentry in ecryptfs
171 * @mode: The mode of the new file
173 * Creates the underlying file and the eCryptfs inode which will link to
174 * it. It will also update the eCryptfs directory inode to mimic the
175 * stat of the lower directory inode.
177 * Returns the new eCryptfs inode on success; an ERR_PTR on error condition
179 static struct inode *
180 ecryptfs_do_create(struct inode *directory_inode,
181 struct dentry *ecryptfs_dentry, umode_t mode)
184 struct dentry *lower_dentry;
185 struct dentry *lower_dir_dentry;
188 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
189 lower_dir_dentry = lock_parent(lower_dentry);
190 rc = vfs_create(d_inode(lower_dir_dentry), lower_dentry, mode, true);
192 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
193 "rc = [%d]\n", __func__, rc);
197 inode = __ecryptfs_get_inode(d_inode(lower_dentry),
198 directory_inode->i_sb);
200 vfs_unlink(d_inode(lower_dir_dentry), lower_dentry, NULL);
203 fsstack_copy_attr_times(directory_inode, d_inode(lower_dir_dentry));
204 fsstack_copy_inode_size(directory_inode, d_inode(lower_dir_dentry));
206 unlock_dir(lower_dir_dentry);
211 * ecryptfs_initialize_file
213 * Cause the file to be changed from a basic empty file to an ecryptfs
214 * file with a header and first data page.
216 * Returns zero on success
218 int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry,
219 struct inode *ecryptfs_inode)
221 struct ecryptfs_crypt_stat *crypt_stat =
222 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
225 if (S_ISDIR(ecryptfs_inode->i_mode)) {
226 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
227 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
230 ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
231 rc = ecryptfs_new_file_context(ecryptfs_inode);
233 ecryptfs_printk(KERN_ERR, "Error creating new file "
234 "context; rc = [%d]\n", rc);
237 rc = ecryptfs_get_lower_file(ecryptfs_dentry, ecryptfs_inode);
239 printk(KERN_ERR "%s: Error attempting to initialize "
240 "the lower file for the dentry with name "
241 "[%pd]; rc = [%d]\n", __func__,
242 ecryptfs_dentry, rc);
245 rc = ecryptfs_write_metadata(ecryptfs_dentry, ecryptfs_inode);
247 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
248 ecryptfs_put_lower_file(ecryptfs_inode);
255 * @dir: The inode of the directory in which to create the file.
256 * @dentry: The eCryptfs dentry
257 * @mode: The mode of the new file.
259 * Creates a new file.
261 * Returns zero on success; non-zero on error condition
264 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
265 umode_t mode, bool excl)
267 struct inode *ecryptfs_inode;
270 ecryptfs_inode = ecryptfs_do_create(directory_inode, ecryptfs_dentry,
272 if (IS_ERR(ecryptfs_inode)) {
273 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
274 "lower filesystem\n");
275 rc = PTR_ERR(ecryptfs_inode);
278 /* At this point, a file exists on "disk"; we need to make sure
279 * that this on disk file is prepared to be an ecryptfs file */
280 rc = ecryptfs_initialize_file(ecryptfs_dentry, ecryptfs_inode);
282 ecryptfs_do_unlink(directory_inode, ecryptfs_dentry,
284 iget_failed(ecryptfs_inode);
287 d_instantiate_new(ecryptfs_dentry, ecryptfs_inode);
292 static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode)
294 struct ecryptfs_crypt_stat *crypt_stat;
297 rc = ecryptfs_get_lower_file(dentry, inode);
299 printk(KERN_ERR "%s: Error attempting to initialize "
300 "the lower file for the dentry with name "
301 "[%pd]; rc = [%d]\n", __func__,
306 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
307 /* TODO: lock for crypt_stat comparison */
308 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
309 ecryptfs_set_default_sizes(crypt_stat);
311 rc = ecryptfs_read_and_validate_header_region(inode);
312 ecryptfs_put_lower_file(inode);
314 rc = ecryptfs_read_and_validate_xattr_region(dentry, inode);
316 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
319 /* Must return 0 to allow non-eCryptfs files to be looked up, too */
324 * ecryptfs_lookup_interpose - Dentry interposition for a lookup
326 static struct dentry *ecryptfs_lookup_interpose(struct dentry *dentry,
327 struct dentry *lower_dentry)
329 struct path *path = ecryptfs_dentry_to_lower_path(dentry->d_parent);
330 struct inode *inode, *lower_inode;
331 struct ecryptfs_dentry_info *dentry_info;
334 dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
336 printk(KERN_ERR "%s: Out of memory whilst attempting "
337 "to allocate ecryptfs_dentry_info struct\n",
340 return ERR_PTR(-ENOMEM);
343 fsstack_copy_attr_atime(d_inode(dentry->d_parent),
344 d_inode(path->dentry));
345 BUG_ON(!d_count(lower_dentry));
347 ecryptfs_set_dentry_private(dentry, dentry_info);
348 dentry_info->lower_path.mnt = mntget(path->mnt);
349 dentry_info->lower_path.dentry = lower_dentry;
352 * negative dentry can go positive under us here - its parent is not
353 * locked. That's OK and that could happen just as we return from
354 * ecryptfs_lookup() anyway. Just need to be careful and fetch
355 * ->d_inode only once - it's not stable here.
357 lower_inode = READ_ONCE(lower_dentry->d_inode);
360 /* We want to add because we couldn't find in lower */
364 inode = __ecryptfs_get_inode(lower_inode, dentry->d_sb);
366 printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
367 __func__, PTR_ERR(inode));
368 return ERR_CAST(inode);
370 if (S_ISREG(inode->i_mode)) {
371 rc = ecryptfs_i_size_read(dentry, inode);
373 make_bad_inode(inode);
378 if (inode->i_state & I_NEW)
379 unlock_new_inode(inode);
380 return d_splice_alias(inode, dentry);
385 * @ecryptfs_dir_inode: The eCryptfs directory inode
386 * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
387 * @flags: lookup flags
389 * Find a file on disk. If the file does not exist, then we'll add it to the
390 * dentry cache and continue on to read it from the disk.
392 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
393 struct dentry *ecryptfs_dentry,
396 char *encrypted_and_encoded_name = NULL;
397 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
398 struct dentry *lower_dir_dentry, *lower_dentry;
399 const char *name = ecryptfs_dentry->d_name.name;
400 size_t len = ecryptfs_dentry->d_name.len;
404 lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
406 mount_crypt_stat = &ecryptfs_superblock_to_private(
407 ecryptfs_dentry->d_sb)->mount_crypt_stat;
409 && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) {
410 rc = ecryptfs_encrypt_and_encode_filename(
411 &encrypted_and_encoded_name, &len,
412 mount_crypt_stat, name, len);
414 printk(KERN_ERR "%s: Error attempting to encrypt and encode "
415 "filename; rc = [%d]\n", __func__, rc);
418 name = encrypted_and_encoded_name;
421 lower_dentry = lookup_one_len_unlocked(name, lower_dir_dentry, len);
422 if (IS_ERR(lower_dentry)) {
423 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
424 "[%ld] on lower_dentry = [%s]\n", __func__,
425 PTR_ERR(lower_dentry),
427 res = ERR_CAST(lower_dentry);
429 res = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry);
431 kfree(encrypted_and_encoded_name);
435 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
436 struct dentry *new_dentry)
438 struct dentry *lower_old_dentry;
439 struct dentry *lower_new_dentry;
440 struct dentry *lower_dir_dentry;
444 file_size_save = i_size_read(d_inode(old_dentry));
445 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
446 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
447 dget(lower_old_dentry);
448 dget(lower_new_dentry);
449 lower_dir_dentry = lock_parent(lower_new_dentry);
450 rc = vfs_link(lower_old_dentry, d_inode(lower_dir_dentry),
451 lower_new_dentry, NULL);
452 if (rc || d_really_is_negative(lower_new_dentry))
454 rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
457 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
458 fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
459 set_nlink(d_inode(old_dentry),
460 ecryptfs_inode_to_lower(d_inode(old_dentry))->i_nlink);
461 i_size_write(d_inode(new_dentry), file_size_save);
463 unlock_dir(lower_dir_dentry);
464 dput(lower_new_dentry);
465 dput(lower_old_dentry);
469 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
471 return ecryptfs_do_unlink(dir, dentry, d_inode(dentry));
474 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
478 struct dentry *lower_dentry;
479 struct dentry *lower_dir_dentry;
480 char *encoded_symname;
481 size_t encoded_symlen;
482 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
484 lower_dentry = ecryptfs_dentry_to_lower(dentry);
486 lower_dir_dentry = lock_parent(lower_dentry);
487 mount_crypt_stat = &ecryptfs_superblock_to_private(
488 dir->i_sb)->mount_crypt_stat;
489 rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
491 mount_crypt_stat, symname,
495 rc = vfs_symlink(d_inode(lower_dir_dentry), lower_dentry,
497 kfree(encoded_symname);
498 if (rc || d_really_is_negative(lower_dentry))
500 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
503 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
504 fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
506 unlock_dir(lower_dir_dentry);
508 if (d_really_is_negative(dentry))
513 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
516 struct dentry *lower_dentry;
517 struct dentry *lower_dir_dentry;
519 lower_dentry = ecryptfs_dentry_to_lower(dentry);
520 lower_dir_dentry = lock_parent(lower_dentry);
521 rc = vfs_mkdir(d_inode(lower_dir_dentry), lower_dentry, mode);
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));
529 set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
531 unlock_dir(lower_dir_dentry);
532 if (d_really_is_negative(dentry))
537 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
539 struct dentry *lower_dentry;
540 struct dentry *lower_dir_dentry;
543 lower_dentry = ecryptfs_dentry_to_lower(dentry);
545 lower_dir_dentry = lock_parent(lower_dentry);
547 rc = vfs_rmdir(d_inode(lower_dir_dentry), lower_dentry);
549 if (!rc && d_really_is_positive(dentry))
550 clear_nlink(d_inode(dentry));
551 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
552 set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
553 unlock_dir(lower_dir_dentry);
561 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
564 struct dentry *lower_dentry;
565 struct dentry *lower_dir_dentry;
567 lower_dentry = ecryptfs_dentry_to_lower(dentry);
568 lower_dir_dentry = lock_parent(lower_dentry);
569 rc = vfs_mknod(d_inode(lower_dir_dentry), lower_dentry, mode, dev);
570 if (rc || d_really_is_negative(lower_dentry))
572 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
575 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
576 fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
578 unlock_dir(lower_dir_dentry);
579 if (d_really_is_negative(dentry))
585 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
586 struct inode *new_dir, struct dentry *new_dentry,
590 struct dentry *lower_old_dentry;
591 struct dentry *lower_new_dentry;
592 struct dentry *lower_old_dir_dentry;
593 struct dentry *lower_new_dir_dentry;
594 struct dentry *trap = NULL;
595 struct inode *target_inode;
600 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
601 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
602 dget(lower_old_dentry);
603 dget(lower_new_dentry);
604 lower_old_dir_dentry = dget_parent(lower_old_dentry);
605 lower_new_dir_dentry = dget_parent(lower_new_dentry);
606 target_inode = d_inode(new_dentry);
607 trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
608 /* source should not be ancestor of target */
609 if (trap == lower_old_dentry) {
613 /* target should not be ancestor of source */
614 if (trap == lower_new_dentry) {
618 rc = vfs_rename(d_inode(lower_old_dir_dentry), lower_old_dentry,
619 d_inode(lower_new_dir_dentry), lower_new_dentry,
624 fsstack_copy_attr_all(target_inode,
625 ecryptfs_inode_to_lower(target_inode));
626 fsstack_copy_attr_all(new_dir, d_inode(lower_new_dir_dentry));
627 if (new_dir != old_dir)
628 fsstack_copy_attr_all(old_dir, d_inode(lower_old_dir_dentry));
630 unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
631 dput(lower_new_dir_dentry);
632 dput(lower_old_dir_dentry);
633 dput(lower_new_dentry);
634 dput(lower_old_dentry);
638 static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
640 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
646 lower_buf = kmalloc(PATH_MAX, GFP_KERNEL);
648 return ERR_PTR(-ENOMEM);
651 rc = d_inode(lower_dentry)->i_op->readlink(lower_dentry,
652 (char __user *)lower_buf,
657 rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb,
661 return rc ? ERR_PTR(rc) : buf;
664 static const char *ecryptfs_get_link(struct dentry *dentry,
666 struct delayed_call *done)
672 return ERR_PTR(-ECHILD);
674 buf = ecryptfs_readlink_lower(dentry, &len);
677 fsstack_copy_attr_atime(d_inode(dentry),
678 d_inode(ecryptfs_dentry_to_lower(dentry)));
680 set_delayed_call(done, kfree_link, buf);
685 * upper_size_to_lower_size
686 * @crypt_stat: Crypt_stat associated with file
687 * @upper_size: Size of the upper file
689 * Calculate the required size of the lower file based on the
690 * specified size of the upper file. This calculation is based on the
691 * number of headers in the underlying file and the extent size.
693 * Returns Calculated size of the lower file.
696 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
701 lower_size = ecryptfs_lower_header_size(crypt_stat);
702 if (upper_size != 0) {
705 num_extents = upper_size >> crypt_stat->extent_shift;
706 if (upper_size & ~crypt_stat->extent_mask)
708 lower_size += (num_extents * crypt_stat->extent_size);
715 * @dentry: The ecryptfs layer dentry
716 * @ia: Address of the ecryptfs inode's attributes
717 * @lower_ia: Address of the lower inode's attributes
719 * Function to handle truncations modifying the size of the file. Note
720 * that the file sizes are interpolated. When expanding, we are simply
721 * writing strings of 0's out. When truncating, we truncate the upper
722 * inode and update the lower_ia according to the page index
723 * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
724 * the caller must use lower_ia in a call to notify_change() to perform
725 * the truncation of the lower inode.
727 * Returns zero on success; non-zero otherwise
729 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
730 struct iattr *lower_ia)
733 struct inode *inode = d_inode(dentry);
734 struct ecryptfs_crypt_stat *crypt_stat;
735 loff_t i_size = i_size_read(inode);
736 loff_t lower_size_before_truncate;
737 loff_t lower_size_after_truncate;
739 if (unlikely((ia->ia_size == i_size))) {
740 lower_ia->ia_valid &= ~ATTR_SIZE;
743 rc = ecryptfs_get_lower_file(dentry, inode);
746 crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
747 /* Switch on growing or shrinking file */
748 if (ia->ia_size > i_size) {
749 char zero[] = { 0x00 };
751 lower_ia->ia_valid &= ~ATTR_SIZE;
752 /* Write a single 0 at the last position of the file;
753 * this triggers code that will fill in 0's throughout
754 * the intermediate portion of the previous end of the
755 * file and the new and of the file */
756 rc = ecryptfs_write(inode, zero,
757 (ia->ia_size - 1), 1);
758 } else { /* ia->ia_size < i_size_read(inode) */
759 /* We're chopping off all the pages down to the page
760 * in which ia->ia_size is located. Fill in the end of
761 * that page from (ia->ia_size & ~PAGE_MASK) to
762 * PAGE_SIZE with zeros. */
763 size_t num_zeros = (PAGE_SIZE
764 - (ia->ia_size & ~PAGE_MASK));
766 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
767 truncate_setsize(inode, ia->ia_size);
768 lower_ia->ia_size = ia->ia_size;
769 lower_ia->ia_valid |= ATTR_SIZE;
775 zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
780 rc = ecryptfs_write(inode, zeros_virt,
781 ia->ia_size, num_zeros);
784 printk(KERN_ERR "Error attempting to zero out "
785 "the remainder of the end page on "
786 "reducing truncate; rc = [%d]\n", rc);
790 truncate_setsize(inode, ia->ia_size);
791 rc = ecryptfs_write_inode_size_to_metadata(inode);
793 printk(KERN_ERR "Problem with "
794 "ecryptfs_write_inode_size_to_metadata; "
798 /* We are reducing the size of the ecryptfs file, and need to
799 * know if we need to reduce the size of the lower file. */
800 lower_size_before_truncate =
801 upper_size_to_lower_size(crypt_stat, i_size);
802 lower_size_after_truncate =
803 upper_size_to_lower_size(crypt_stat, ia->ia_size);
804 if (lower_size_after_truncate < lower_size_before_truncate) {
805 lower_ia->ia_size = lower_size_after_truncate;
806 lower_ia->ia_valid |= ATTR_SIZE;
808 lower_ia->ia_valid &= ~ATTR_SIZE;
811 ecryptfs_put_lower_file(inode);
815 static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset)
817 struct ecryptfs_crypt_stat *crypt_stat;
818 loff_t lower_oldsize, lower_newsize;
820 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
821 lower_oldsize = upper_size_to_lower_size(crypt_stat,
823 lower_newsize = upper_size_to_lower_size(crypt_stat, offset);
824 if (lower_newsize > lower_oldsize) {
826 * The eCryptfs inode and the new *lower* size are mixed here
827 * because we may not have the lower i_mutex held and/or it may
828 * not be appropriate to call inode_newsize_ok() with inodes
829 * from other filesystems.
831 return inode_newsize_ok(inode, lower_newsize);
839 * @dentry: The ecryptfs layer dentry
840 * @new_length: The length to expand the file to
842 * Simple function that handles the truncation of an eCryptfs inode and
843 * its corresponding lower inode.
845 * Returns zero on success; non-zero otherwise
847 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
849 struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
850 struct iattr lower_ia = { .ia_valid = 0 };
853 rc = ecryptfs_inode_newsize_ok(d_inode(dentry), new_length);
857 rc = truncate_upper(dentry, &ia, &lower_ia);
858 if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
859 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
861 inode_lock(d_inode(lower_dentry));
862 rc = notify_change(lower_dentry, &lower_ia, NULL);
863 inode_unlock(d_inode(lower_dentry));
869 ecryptfs_permission(struct inode *inode, int mask)
871 return inode_permission(ecryptfs_inode_to_lower(inode), mask);
876 * @dentry: dentry handle to the inode to modify
877 * @ia: Structure with flags of what to change and values
879 * Updates the metadata of an inode. If the update is to the size
880 * i.e. truncation, then ecryptfs_truncate will handle the size modification
881 * of both the ecryptfs inode and the lower inode.
883 * All other metadata changes will be passed right to the lower filesystem,
884 * and we will just update our inode to look like the lower.
886 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
889 struct dentry *lower_dentry;
890 struct iattr lower_ia;
892 struct inode *lower_inode;
893 struct ecryptfs_crypt_stat *crypt_stat;
895 crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
896 if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)) {
897 rc = ecryptfs_init_crypt_stat(crypt_stat);
901 inode = d_inode(dentry);
902 lower_inode = ecryptfs_inode_to_lower(inode);
903 lower_dentry = ecryptfs_dentry_to_lower(dentry);
904 mutex_lock(&crypt_stat->cs_mutex);
905 if (d_is_dir(dentry))
906 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
907 else if (d_is_reg(dentry)
908 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
909 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
910 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
912 mount_crypt_stat = &ecryptfs_superblock_to_private(
913 dentry->d_sb)->mount_crypt_stat;
914 rc = ecryptfs_get_lower_file(dentry, inode);
916 mutex_unlock(&crypt_stat->cs_mutex);
919 rc = ecryptfs_read_metadata(dentry);
920 ecryptfs_put_lower_file(inode);
922 if (!(mount_crypt_stat->flags
923 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
925 printk(KERN_WARNING "Either the lower file "
926 "is not in a valid eCryptfs format, "
927 "or the key could not be retrieved. "
928 "Plaintext passthrough mode is not "
929 "enabled; returning -EIO\n");
930 mutex_unlock(&crypt_stat->cs_mutex);
934 crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
935 | ECRYPTFS_ENCRYPTED);
938 mutex_unlock(&crypt_stat->cs_mutex);
940 rc = setattr_prepare(dentry, ia);
943 if (ia->ia_valid & ATTR_SIZE) {
944 rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size);
949 memcpy(&lower_ia, ia, sizeof(lower_ia));
950 if (ia->ia_valid & ATTR_FILE)
951 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
952 if (ia->ia_valid & ATTR_SIZE) {
953 rc = truncate_upper(dentry, ia, &lower_ia);
959 * mode change is for clearing setuid/setgid bits. Allow lower fs
960 * to interpret this in its own way.
962 if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
963 lower_ia.ia_valid &= ~ATTR_MODE;
965 inode_lock(d_inode(lower_dentry));
966 rc = notify_change(lower_dentry, &lower_ia, NULL);
967 inode_unlock(d_inode(lower_dentry));
969 fsstack_copy_attr_all(inode, lower_inode);
973 static int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
976 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
979 mount_crypt_stat = &ecryptfs_superblock_to_private(
980 dentry->d_sb)->mount_crypt_stat;
981 generic_fillattr(d_inode(dentry), stat);
982 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
986 target = ecryptfs_readlink_lower(dentry, &targetsiz);
987 if (!IS_ERR(target)) {
989 stat->size = targetsiz;
991 rc = PTR_ERR(target);
997 static int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
1000 struct kstat lower_stat;
1003 rc = vfs_getattr(ecryptfs_dentry_to_lower_path(dentry), &lower_stat);
1005 fsstack_copy_attr_all(d_inode(dentry),
1006 ecryptfs_inode_to_lower(d_inode(dentry)));
1007 generic_fillattr(d_inode(dentry), stat);
1008 stat->blocks = lower_stat.blocks;
1014 ecryptfs_setxattr(struct dentry *dentry, struct inode *inode,
1015 const char *name, const void *value,
1016 size_t size, int flags)
1019 struct dentry *lower_dentry;
1021 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1022 if (!(d_inode(lower_dentry)->i_opflags & IOP_XATTR)) {
1026 rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1028 fsstack_copy_attr_all(inode, d_inode(lower_dentry));
1034 ecryptfs_getxattr_lower(struct dentry *lower_dentry, struct inode *lower_inode,
1035 const char *name, void *value, size_t size)
1039 if (!(lower_inode->i_opflags & IOP_XATTR)) {
1043 inode_lock(lower_inode);
1044 rc = __vfs_getxattr(lower_dentry, lower_inode, name, value, size);
1045 inode_unlock(lower_inode);
1051 ecryptfs_getxattr(struct dentry *dentry, struct inode *inode,
1052 const char *name, void *value, size_t size)
1054 return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
1055 ecryptfs_inode_to_lower(inode),
1060 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1063 struct dentry *lower_dentry;
1065 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1066 if (!d_inode(lower_dentry)->i_op->listxattr) {
1070 inode_lock(d_inode(lower_dentry));
1071 rc = d_inode(lower_dentry)->i_op->listxattr(lower_dentry, list, size);
1072 inode_unlock(d_inode(lower_dentry));
1077 static int ecryptfs_removexattr(struct dentry *dentry, struct inode *inode,
1081 struct dentry *lower_dentry;
1082 struct inode *lower_inode;
1084 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1085 lower_inode = ecryptfs_inode_to_lower(inode);
1086 if (!(lower_inode->i_opflags & IOP_XATTR)) {
1090 inode_lock(lower_inode);
1091 rc = __vfs_removexattr(lower_dentry, name);
1092 inode_unlock(lower_inode);
1097 const struct inode_operations ecryptfs_symlink_iops = {
1098 .readlink = generic_readlink,
1099 .get_link = ecryptfs_get_link,
1100 .permission = ecryptfs_permission,
1101 .setattr = ecryptfs_setattr,
1102 .getattr = ecryptfs_getattr_link,
1103 .listxattr = ecryptfs_listxattr,
1106 const struct inode_operations ecryptfs_dir_iops = {
1107 .create = ecryptfs_create,
1108 .lookup = ecryptfs_lookup,
1109 .link = ecryptfs_link,
1110 .unlink = ecryptfs_unlink,
1111 .symlink = ecryptfs_symlink,
1112 .mkdir = ecryptfs_mkdir,
1113 .rmdir = ecryptfs_rmdir,
1114 .mknod = ecryptfs_mknod,
1115 .rename = ecryptfs_rename,
1116 .permission = ecryptfs_permission,
1117 .setattr = ecryptfs_setattr,
1118 .listxattr = ecryptfs_listxattr,
1121 const struct inode_operations ecryptfs_main_iops = {
1122 .permission = ecryptfs_permission,
1123 .setattr = ecryptfs_setattr,
1124 .getattr = ecryptfs_getattr,
1125 .listxattr = ecryptfs_listxattr,
1128 static int ecryptfs_xattr_get(const struct xattr_handler *handler,
1129 struct dentry *dentry, struct inode *inode,
1130 const char *name, void *buffer, size_t size)
1132 return ecryptfs_getxattr(dentry, inode, name, buffer, size);
1135 static int ecryptfs_xattr_set(const struct xattr_handler *handler,
1136 struct dentry *dentry, struct inode *inode,
1137 const char *name, const void *value, size_t size,
1141 return ecryptfs_setxattr(dentry, inode, name, value, size, flags);
1143 BUG_ON(flags != XATTR_REPLACE);
1144 return ecryptfs_removexattr(dentry, inode, name);
1148 const struct xattr_handler ecryptfs_xattr_handler = {
1149 .prefix = "", /* match anything */
1150 .get = ecryptfs_xattr_get,
1151 .set = ecryptfs_xattr_set,
1154 const struct xattr_handler *ecryptfs_xattr_handlers[] = {
1155 &ecryptfs_xattr_handler,