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 <asm/unaligned.h>
35 #include "ecryptfs_kernel.h"
37 static struct dentry *lock_parent(struct dentry *dentry)
41 dir = dget_parent(dentry);
42 mutex_lock_nested(&(dir->d_inode->i_mutex), I_MUTEX_PARENT);
46 static void unlock_dir(struct dentry *dir)
48 mutex_unlock(&dir->d_inode->i_mutex);
53 * ecryptfs_create_underlying_file
54 * @lower_dir_inode: inode of the parent in the lower fs of the new file
55 * @lower_dentry: New file's dentry in the lower fs
56 * @ecryptfs_dentry: New file's dentry in ecryptfs
57 * @mode: The mode of the new file
58 * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
60 * Creates the file in the lower file system.
62 * Returns zero on success; non-zero on error condition
65 ecryptfs_create_underlying_file(struct inode *lower_dir_inode,
66 struct dentry *dentry, int mode,
69 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
70 struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
71 struct dentry *dentry_save;
72 struct vfsmount *vfsmount_save;
75 dentry_save = nd->path.dentry;
76 vfsmount_save = nd->path.mnt;
77 nd->path.dentry = lower_dentry;
78 nd->path.mnt = lower_mnt;
79 rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd);
80 nd->path.dentry = dentry_save;
81 nd->path.mnt = vfsmount_save;
87 * @directory_inode: inode of the new file's dentry's parent in ecryptfs
88 * @ecryptfs_dentry: New file's dentry in ecryptfs
89 * @mode: The mode of the new file
90 * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
92 * Creates the underlying file and the eCryptfs inode which will link to
93 * it. It will also update the eCryptfs directory inode to mimic the
94 * stat of the lower directory inode.
96 * Returns zero on success; non-zero on error condition
99 ecryptfs_do_create(struct inode *directory_inode,
100 struct dentry *ecryptfs_dentry, int mode,
101 struct nameidata *nd)
104 struct dentry *lower_dentry;
105 struct dentry *lower_dir_dentry;
107 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
108 lower_dir_dentry = lock_parent(lower_dentry);
109 if (IS_ERR(lower_dir_dentry)) {
110 ecryptfs_printk(KERN_ERR, "Error locking directory of "
112 rc = PTR_ERR(lower_dir_dentry);
115 rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
116 ecryptfs_dentry, mode, nd);
118 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
119 "rc = [%d]\n", __func__, rc);
122 rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
123 directory_inode->i_sb, 0);
125 ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n");
128 fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
129 fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode);
131 unlock_dir(lower_dir_dentry);
138 * @ecryptfs_dentry: the eCryptfs dentry
140 * This is the code which will grow the file to its correct size.
142 static int grow_file(struct dentry *ecryptfs_dentry)
144 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
145 struct file fake_file;
146 struct ecryptfs_file_info tmp_file_info;
147 char zero_virt[] = { 0x00 };
150 memset(&fake_file, 0, sizeof(fake_file));
151 fake_file.f_path.dentry = ecryptfs_dentry;
152 memset(&tmp_file_info, 0, sizeof(tmp_file_info));
153 ecryptfs_set_file_private(&fake_file, &tmp_file_info);
154 ecryptfs_set_file_lower(
156 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file);
157 rc = ecryptfs_write(&fake_file, zero_virt, 0, 1);
158 i_size_write(ecryptfs_inode, 0);
159 rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode);
160 ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat.flags |=
166 * ecryptfs_initialize_file
168 * Cause the file to be changed from a basic empty file to an ecryptfs
169 * file with a header and first data page.
171 * Returns zero on success
173 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
175 struct ecryptfs_crypt_stat *crypt_stat =
176 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
179 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
180 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
181 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
184 crypt_stat->flags |= ECRYPTFS_NEW_FILE;
185 ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
186 rc = ecryptfs_new_file_context(ecryptfs_dentry);
188 ecryptfs_printk(KERN_ERR, "Error creating new file "
189 "context; rc = [%d]\n", rc);
192 if (!ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->lower_file) {
193 rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
195 printk(KERN_ERR "%s: Error attempting to initialize "
196 "the persistent file for the dentry with name "
197 "[%s]; rc = [%d]\n", __func__,
198 ecryptfs_dentry->d_name.name, rc);
202 rc = ecryptfs_write_metadata(ecryptfs_dentry);
204 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
207 rc = grow_file(ecryptfs_dentry);
209 printk(KERN_ERR "Error growing file; rc = [%d]\n", rc);
216 * @dir: The inode of the directory in which to create the file.
217 * @dentry: The eCryptfs dentry
218 * @mode: The mode of the new file.
221 * Creates a new file.
223 * Returns zero on success; non-zero on error condition
226 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
227 int mode, struct nameidata *nd)
231 /* ecryptfs_do_create() calls ecryptfs_interpose() */
232 rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
234 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
235 "lower filesystem\n");
238 /* At this point, a file exists on "disk"; we need to make sure
239 * that this on disk file is prepared to be an ecryptfs file */
240 rc = ecryptfs_initialize_file(ecryptfs_dentry);
246 * ecryptfs_lookup_and_interpose_lower - Perform a lookup
248 int ecryptfs_lookup_and_interpose_lower(struct dentry *ecryptfs_dentry,
249 struct dentry *lower_dentry,
250 struct ecryptfs_crypt_stat *crypt_stat,
251 struct inode *ecryptfs_dir_inode,
252 struct nameidata *ecryptfs_nd)
254 struct dentry *lower_dir_dentry;
255 struct vfsmount *lower_mnt;
256 struct inode *lower_inode;
257 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
258 char *page_virt = NULL;
262 lower_dir_dentry = lower_dentry->d_parent;
263 lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(
264 ecryptfs_dentry->d_parent));
265 lower_inode = lower_dentry->d_inode;
266 fsstack_copy_attr_atime(ecryptfs_dir_inode, lower_dir_dentry->d_inode);
267 BUG_ON(!atomic_read(&lower_dentry->d_count));
268 ecryptfs_set_dentry_private(ecryptfs_dentry,
269 kmem_cache_alloc(ecryptfs_dentry_info_cache,
271 if (!ecryptfs_dentry_to_private(ecryptfs_dentry)) {
273 printk(KERN_ERR "%s: Out of memory whilst attempting "
274 "to allocate ecryptfs_dentry_info struct\n",
278 ecryptfs_set_dentry_lower(ecryptfs_dentry, lower_dentry);
279 ecryptfs_set_dentry_lower_mnt(ecryptfs_dentry, lower_mnt);
280 if (!lower_dentry->d_inode) {
281 /* We want to add because we couldn't find in lower */
282 d_add(ecryptfs_dentry, NULL);
285 rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
286 ecryptfs_dir_inode->i_sb, 1);
288 printk(KERN_ERR "%s: Error interposing; rc = [%d]\n",
292 if (S_ISDIR(lower_inode->i_mode))
294 if (S_ISLNK(lower_inode->i_mode))
296 if (special_file(lower_inode->i_mode))
300 /* Released in this function */
301 page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2, GFP_USER);
303 printk(KERN_ERR "%s: Cannot kmem_cache_zalloc() a page\n",
308 if (!ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->lower_file) {
309 rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
311 printk(KERN_ERR "%s: Error attempting to initialize "
312 "the persistent file for the dentry with name "
313 "[%s]; rc = [%d]\n", __func__,
314 ecryptfs_dentry->d_name.name, rc);
318 rc = ecryptfs_read_and_validate_header_region(page_virt,
319 ecryptfs_dentry->d_inode);
321 rc = ecryptfs_read_and_validate_xattr_region(page_virt,
327 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
329 mount_crypt_stat = &ecryptfs_superblock_to_private(
330 ecryptfs_dentry->d_sb)->mount_crypt_stat;
331 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
332 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
333 file_size = (crypt_stat->num_header_bytes_at_front
334 + i_size_read(lower_dentry->d_inode));
336 file_size = i_size_read(lower_dentry->d_inode);
338 file_size = get_unaligned_be64(page_virt);
340 i_size_write(ecryptfs_dentry->d_inode, (loff_t)file_size);
342 kmem_cache_free(ecryptfs_header_cache_2, page_virt);
346 d_drop(ecryptfs_dentry);
353 * @ecryptfs_dir_inode: The eCryptfs directory inode
354 * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
355 * @ecryptfs_nd: nameidata; may be NULL
357 * Find a file on disk. If the file does not exist, then we'll add it to the
358 * dentry cache and continue on to read it from the disk.
360 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
361 struct dentry *ecryptfs_dentry,
362 struct nameidata *ecryptfs_nd)
364 char *encrypted_and_encoded_name = NULL;
365 int encrypted_and_encoded_name_size;
366 struct ecryptfs_crypt_stat *crypt_stat = NULL;
367 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
368 struct ecryptfs_inode_info *inode_info;
369 struct dentry *lower_dir_dentry, *lower_dentry;
372 ecryptfs_dentry->d_op = &ecryptfs_dops;
373 if ((ecryptfs_dentry->d_name.len == 1
374 && !strcmp(ecryptfs_dentry->d_name.name, "."))
375 || (ecryptfs_dentry->d_name.len == 2
376 && !strcmp(ecryptfs_dentry->d_name.name, ".."))) {
379 lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
380 lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name,
382 ecryptfs_dentry->d_name.len);
383 if (IS_ERR(lower_dentry)) {
384 rc = PTR_ERR(lower_dentry);
385 printk(KERN_ERR "%s: lookup_one_len() returned [%d] on "
386 "lower_dentry = [%s]\n", __func__, rc,
387 ecryptfs_dentry->d_name.name);
390 if (lower_dentry->d_inode)
391 goto lookup_and_interpose;
392 inode_info = ecryptfs_inode_to_private(ecryptfs_dentry->d_inode);
394 crypt_stat = &inode_info->crypt_stat;
395 /* TODO: lock for crypt_stat comparison */
396 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
397 ecryptfs_set_default_sizes(crypt_stat);
400 mount_crypt_stat = crypt_stat->mount_crypt_stat;
402 mount_crypt_stat = &ecryptfs_superblock_to_private(
403 ecryptfs_dentry->d_sb)->mount_crypt_stat;
404 if (!(crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCRYPT_FILENAMES))
405 && !(mount_crypt_stat && (mount_crypt_stat->flags
406 & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)))
407 goto lookup_and_interpose;
409 rc = ecryptfs_encrypt_and_encode_filename(
410 &encrypted_and_encoded_name, &encrypted_and_encoded_name_size,
411 crypt_stat, mount_crypt_stat, ecryptfs_dentry->d_name.name,
412 ecryptfs_dentry->d_name.len);
414 printk(KERN_ERR "%s: Error attempting to encrypt and encode "
415 "filename; rc = [%d]\n", __func__, rc);
418 lower_dentry = lookup_one_len(encrypted_and_encoded_name,
420 encrypted_and_encoded_name_size - 1);
421 if (IS_ERR(lower_dentry)) {
422 rc = PTR_ERR(lower_dentry);
423 printk(KERN_ERR "%s: lookup_one_len() returned [%d] on "
424 "lower_dentry = [%s]\n", __func__, rc,
425 encrypted_and_encoded_name);
428 lookup_and_interpose:
429 rc = ecryptfs_lookup_and_interpose_lower(ecryptfs_dentry, lower_dentry,
430 crypt_stat, ecryptfs_dir_inode,
434 d_drop(ecryptfs_dentry);
436 kfree(encrypted_and_encoded_name);
440 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
441 struct dentry *new_dentry)
443 struct dentry *lower_old_dentry;
444 struct dentry *lower_new_dentry;
445 struct dentry *lower_dir_dentry;
449 file_size_save = i_size_read(old_dentry->d_inode);
450 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
451 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
452 dget(lower_old_dentry);
453 dget(lower_new_dentry);
454 lower_dir_dentry = lock_parent(lower_new_dentry);
455 rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
457 if (rc || !lower_new_dentry->d_inode)
459 rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
462 fsstack_copy_attr_times(dir, lower_new_dentry->d_inode);
463 fsstack_copy_inode_size(dir, lower_new_dentry->d_inode);
464 old_dentry->d_inode->i_nlink =
465 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
466 i_size_write(new_dentry->d_inode, file_size_save);
468 unlock_dir(lower_dir_dentry);
469 dput(lower_new_dentry);
470 dput(lower_old_dentry);
471 d_drop(lower_old_dentry);
477 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
480 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
481 struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
482 struct dentry *lower_dir_dentry;
484 lower_dir_dentry = lock_parent(lower_dentry);
485 rc = vfs_unlink(lower_dir_inode, lower_dentry);
487 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
490 fsstack_copy_attr_times(dir, lower_dir_inode);
491 dentry->d_inode->i_nlink =
492 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
493 dentry->d_inode->i_ctime = dir->i_ctime;
496 unlock_dir(lower_dir_dentry);
500 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
504 struct dentry *lower_dentry;
505 struct dentry *lower_dir_dentry;
506 char *encoded_symname;
507 size_t encoded_symlen;
508 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
510 lower_dentry = ecryptfs_dentry_to_lower(dentry);
512 lower_dir_dentry = lock_parent(lower_dentry);
513 mount_crypt_stat = &ecryptfs_superblock_to_private(
514 dir->i_sb)->mount_crypt_stat;
515 rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
518 mount_crypt_stat, symname,
522 rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
524 kfree(encoded_symname);
525 if (rc || !lower_dentry->d_inode)
527 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
530 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
531 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
533 unlock_dir(lower_dir_dentry);
535 if (!dentry->d_inode)
540 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
543 struct dentry *lower_dentry;
544 struct dentry *lower_dir_dentry;
546 lower_dentry = ecryptfs_dentry_to_lower(dentry);
547 lower_dir_dentry = lock_parent(lower_dentry);
548 rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
549 if (rc || !lower_dentry->d_inode)
551 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
554 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
555 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
556 dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
558 unlock_dir(lower_dir_dentry);
559 if (!dentry->d_inode)
564 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
566 struct dentry *lower_dentry;
567 struct dentry *lower_dir_dentry;
570 lower_dentry = ecryptfs_dentry_to_lower(dentry);
572 lower_dir_dentry = lock_parent(lower_dentry);
574 rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
577 d_delete(lower_dentry);
578 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
579 dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
580 unlock_dir(lower_dir_dentry);
588 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
591 struct dentry *lower_dentry;
592 struct dentry *lower_dir_dentry;
594 lower_dentry = ecryptfs_dentry_to_lower(dentry);
595 lower_dir_dentry = lock_parent(lower_dentry);
596 rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
597 if (rc || !lower_dentry->d_inode)
599 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
602 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
603 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
605 unlock_dir(lower_dir_dentry);
606 if (!dentry->d_inode)
612 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
613 struct inode *new_dir, struct dentry *new_dentry)
616 struct dentry *lower_old_dentry;
617 struct dentry *lower_new_dentry;
618 struct dentry *lower_old_dir_dentry;
619 struct dentry *lower_new_dir_dentry;
621 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
622 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
623 dget(lower_old_dentry);
624 dget(lower_new_dentry);
625 lower_old_dir_dentry = dget_parent(lower_old_dentry);
626 lower_new_dir_dentry = dget_parent(lower_new_dentry);
627 lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
628 rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
629 lower_new_dir_dentry->d_inode, lower_new_dentry);
632 fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL);
633 if (new_dir != old_dir)
634 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL);
636 unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
637 dput(lower_new_dentry->d_parent);
638 dput(lower_old_dentry->d_parent);
639 dput(lower_new_dentry);
640 dput(lower_old_dentry);
645 ecryptfs_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
648 struct dentry *lower_dentry;
649 struct ecryptfs_crypt_stat *crypt_stat;
650 char *plaintext_name;
651 size_t plaintext_name_size;
655 lower_dentry = ecryptfs_dentry_to_lower(dentry);
656 if (!lower_dentry->d_inode->i_op->readlink) {
660 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
661 /* Released in this function */
662 lower_buf = kmalloc(bufsiz, GFP_KERNEL);
663 if (lower_buf == NULL) {
664 printk(KERN_ERR "%s: Out of memory whilst attempting to "
665 "kmalloc [%d] bytes\n", __func__, bufsiz);
671 rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
672 (char __user *)lower_buf,
676 rc = ecryptfs_decode_and_decrypt_filename(&plaintext_name,
677 &plaintext_name_size,
681 printk(KERN_ERR "%s: Error attempting to decode and "
682 "decrypt filename; rc = [%d]\n", __func__,
684 goto out_free_lower_buf;
686 rc = copy_to_user(buf, plaintext_name, plaintext_name_size);
690 rc = plaintext_name_size;
691 kfree(plaintext_name);
692 fsstack_copy_attr_atime(dentry->d_inode, lower_dentry->d_inode);
700 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
703 int len = PAGE_SIZE, rc;
706 /* Released in ecryptfs_put_link(); only release here on error */
707 buf = kmalloc(len, GFP_KERNEL);
714 rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
721 nd_set_link(nd, buf);
730 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
733 kfree(nd_get_link(nd));
737 * upper_size_to_lower_size
738 * @crypt_stat: Crypt_stat associated with file
739 * @upper_size: Size of the upper file
741 * Calculate the required size of the lower file based on the
742 * specified size of the upper file. This calculation is based on the
743 * number of headers in the underlying file and the extent size.
745 * Returns Calculated size of the lower file.
748 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
753 lower_size = crypt_stat->num_header_bytes_at_front;
754 if (upper_size != 0) {
757 num_extents = upper_size >> crypt_stat->extent_shift;
758 if (upper_size & ~crypt_stat->extent_mask)
760 lower_size += (num_extents * crypt_stat->extent_size);
767 * @dentry: The ecryptfs layer dentry
768 * @new_length: The length to expand the file to
770 * Function to handle truncations modifying the size of the file. Note
771 * that the file sizes are interpolated. When expanding, we are simply
772 * writing strings of 0's out. When truncating, we need to modify the
773 * underlying file size according to the page index interpolations.
775 * Returns zero on success; non-zero otherwise
777 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
780 struct inode *inode = dentry->d_inode;
781 struct dentry *lower_dentry;
782 struct file fake_ecryptfs_file;
783 struct ecryptfs_crypt_stat *crypt_stat;
784 loff_t i_size = i_size_read(inode);
785 loff_t lower_size_before_truncate;
786 loff_t lower_size_after_truncate;
788 if (unlikely((new_length == i_size)))
790 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
791 /* Set up a fake ecryptfs file, this is used to interface with
792 * the file in the underlying filesystem so that the
793 * truncation has an effect there as well. */
794 memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
795 fake_ecryptfs_file.f_path.dentry = dentry;
796 /* Released at out_free: label */
797 ecryptfs_set_file_private(&fake_ecryptfs_file,
798 kmem_cache_alloc(ecryptfs_file_info_cache,
800 if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
804 lower_dentry = ecryptfs_dentry_to_lower(dentry);
805 ecryptfs_set_file_lower(
807 ecryptfs_inode_to_private(dentry->d_inode)->lower_file);
808 /* Switch on growing or shrinking file */
809 if (new_length > i_size) {
810 char zero[] = { 0x00 };
812 /* Write a single 0 at the last position of the file;
813 * this triggers code that will fill in 0's throughout
814 * the intermediate portion of the previous end of the
815 * file and the new and of the file */
816 rc = ecryptfs_write(&fake_ecryptfs_file, zero,
817 (new_length - 1), 1);
818 } else { /* new_length < i_size_read(inode) */
819 /* We're chopping off all the pages down do the page
820 * in which new_length is located. Fill in the end of
821 * that page from (new_length & ~PAGE_CACHE_MASK) to
822 * PAGE_CACHE_SIZE with zeros. */
823 size_t num_zeros = (PAGE_CACHE_SIZE
824 - (new_length & ~PAGE_CACHE_MASK));
829 zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
834 rc = ecryptfs_write(&fake_ecryptfs_file, zeros_virt,
835 new_length, num_zeros);
838 printk(KERN_ERR "Error attempting to zero out "
839 "the remainder of the end page on "
840 "reducing truncate; rc = [%d]\n", rc);
844 vmtruncate(inode, new_length);
845 rc = ecryptfs_write_inode_size_to_metadata(inode);
847 printk(KERN_ERR "Problem with "
848 "ecryptfs_write_inode_size_to_metadata; "
852 /* We are reducing the size of the ecryptfs file, and need to
853 * know if we need to reduce the size of the lower file. */
854 lower_size_before_truncate =
855 upper_size_to_lower_size(crypt_stat, i_size);
856 lower_size_after_truncate =
857 upper_size_to_lower_size(crypt_stat, new_length);
858 if (lower_size_after_truncate < lower_size_before_truncate)
859 vmtruncate(lower_dentry->d_inode,
860 lower_size_after_truncate);
863 if (ecryptfs_file_to_private(&fake_ecryptfs_file))
864 kmem_cache_free(ecryptfs_file_info_cache,
865 ecryptfs_file_to_private(&fake_ecryptfs_file));
871 ecryptfs_permission(struct inode *inode, int mask)
873 return inode_permission(ecryptfs_inode_to_lower(inode), mask);
878 * @dentry: dentry handle to the inode to modify
879 * @ia: Structure with flags of what to change and values
881 * Updates the metadata of an inode. If the update is to the size
882 * i.e. truncation, then ecryptfs_truncate will handle the size modification
883 * of both the ecryptfs inode and the lower inode.
885 * All other metadata changes will be passed right to the lower filesystem,
886 * and we will just update our inode to look like the lower.
888 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
891 struct dentry *lower_dentry;
893 struct inode *lower_inode;
894 struct ecryptfs_crypt_stat *crypt_stat;
896 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
897 if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
898 ecryptfs_init_crypt_stat(crypt_stat);
899 inode = dentry->d_inode;
900 lower_inode = ecryptfs_inode_to_lower(inode);
901 lower_dentry = ecryptfs_dentry_to_lower(dentry);
902 mutex_lock(&crypt_stat->cs_mutex);
903 if (S_ISDIR(dentry->d_inode->i_mode))
904 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
905 else if (S_ISREG(dentry->d_inode->i_mode)
906 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
907 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
908 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
910 mount_crypt_stat = &ecryptfs_superblock_to_private(
911 dentry->d_sb)->mount_crypt_stat;
912 rc = ecryptfs_read_metadata(dentry);
914 if (!(mount_crypt_stat->flags
915 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
917 printk(KERN_WARNING "Either the lower file "
918 "is not in a valid eCryptfs format, "
919 "or the key could not be retrieved. "
920 "Plaintext passthrough mode is not "
921 "enabled; returning -EIO\n");
922 mutex_unlock(&crypt_stat->cs_mutex);
926 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
927 mutex_unlock(&crypt_stat->cs_mutex);
931 mutex_unlock(&crypt_stat->cs_mutex);
932 if (ia->ia_valid & ATTR_SIZE) {
933 ecryptfs_printk(KERN_DEBUG,
934 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
935 ia->ia_valid, ATTR_SIZE);
936 rc = ecryptfs_truncate(dentry, ia->ia_size);
937 /* ecryptfs_truncate handles resizing of the lower file */
938 ia->ia_valid &= ~ATTR_SIZE;
939 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
946 * mode change is for clearing setuid/setgid bits. Allow lower fs
947 * to interpret this in its own way.
949 if (ia->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
950 ia->ia_valid &= ~ATTR_MODE;
952 mutex_lock(&lower_dentry->d_inode->i_mutex);
953 rc = notify_change(lower_dentry, ia);
954 mutex_unlock(&lower_dentry->d_inode->i_mutex);
956 fsstack_copy_attr_all(inode, lower_inode, NULL);
961 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
962 size_t size, int flags)
965 struct dentry *lower_dentry;
967 lower_dentry = ecryptfs_dentry_to_lower(dentry);
968 if (!lower_dentry->d_inode->i_op->setxattr) {
972 mutex_lock(&lower_dentry->d_inode->i_mutex);
973 rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
975 mutex_unlock(&lower_dentry->d_inode->i_mutex);
981 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
982 void *value, size_t size)
986 if (!lower_dentry->d_inode->i_op->getxattr) {
990 mutex_lock(&lower_dentry->d_inode->i_mutex);
991 rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
993 mutex_unlock(&lower_dentry->d_inode->i_mutex);
999 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
1002 return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
1007 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1010 struct dentry *lower_dentry;
1012 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1013 if (!lower_dentry->d_inode->i_op->listxattr) {
1017 mutex_lock(&lower_dentry->d_inode->i_mutex);
1018 rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1019 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1024 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1027 struct dentry *lower_dentry;
1029 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1030 if (!lower_dentry->d_inode->i_op->removexattr) {
1034 mutex_lock(&lower_dentry->d_inode->i_mutex);
1035 rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1036 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1041 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
1043 if ((ecryptfs_inode_to_lower(inode)
1044 == (struct inode *)candidate_lower_inode))
1050 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1052 ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1056 const struct inode_operations ecryptfs_symlink_iops = {
1057 .readlink = ecryptfs_readlink,
1058 .follow_link = ecryptfs_follow_link,
1059 .put_link = ecryptfs_put_link,
1060 .permission = ecryptfs_permission,
1061 .setattr = ecryptfs_setattr,
1062 .setxattr = ecryptfs_setxattr,
1063 .getxattr = ecryptfs_getxattr,
1064 .listxattr = ecryptfs_listxattr,
1065 .removexattr = ecryptfs_removexattr
1068 const struct inode_operations ecryptfs_dir_iops = {
1069 .create = ecryptfs_create,
1070 .lookup = ecryptfs_lookup,
1071 .link = ecryptfs_link,
1072 .unlink = ecryptfs_unlink,
1073 .symlink = ecryptfs_symlink,
1074 .mkdir = ecryptfs_mkdir,
1075 .rmdir = ecryptfs_rmdir,
1076 .mknod = ecryptfs_mknod,
1077 .rename = ecryptfs_rename,
1078 .permission = ecryptfs_permission,
1079 .setattr = ecryptfs_setattr,
1080 .setxattr = ecryptfs_setxattr,
1081 .getxattr = ecryptfs_getxattr,
1082 .listxattr = ecryptfs_listxattr,
1083 .removexattr = ecryptfs_removexattr
1086 const struct inode_operations ecryptfs_main_iops = {
1087 .permission = ecryptfs_permission,
1088 .setattr = ecryptfs_setattr,
1089 .setxattr = ecryptfs_setxattr,
1090 .getxattr = ecryptfs_getxattr,
1091 .listxattr = ecryptfs_listxattr,
1092 .removexattr = ecryptfs_removexattr