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 * @dentry: New file's dentry
56 * @mode: The mode of the new file
57 * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
59 * Creates the file in the lower file system.
61 * Returns zero on success; non-zero on error condition
64 ecryptfs_create_underlying_file(struct inode *lower_dir_inode,
65 struct dentry *dentry, int mode,
68 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
69 struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
70 struct dentry *dentry_save;
71 struct vfsmount *vfsmount_save;
74 dentry_save = nd->path.dentry;
75 vfsmount_save = nd->path.mnt;
76 nd->path.dentry = lower_dentry;
77 nd->path.mnt = lower_mnt;
78 rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd);
79 nd->path.dentry = dentry_save;
80 nd->path.mnt = vfsmount_save;
86 * @directory_inode: inode of the new file's dentry's parent in ecryptfs
87 * @ecryptfs_dentry: New file's dentry in ecryptfs
88 * @mode: The mode of the new file
89 * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
91 * Creates the underlying file and the eCryptfs inode which will link to
92 * it. It will also update the eCryptfs directory inode to mimic the
93 * stat of the lower directory inode.
95 * Returns zero on success; non-zero on error condition
98 ecryptfs_do_create(struct inode *directory_inode,
99 struct dentry *ecryptfs_dentry, int mode,
100 struct nameidata *nd)
103 struct dentry *lower_dentry;
104 struct dentry *lower_dir_dentry;
106 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
107 lower_dir_dentry = lock_parent(lower_dentry);
108 if (IS_ERR(lower_dir_dentry)) {
109 ecryptfs_printk(KERN_ERR, "Error locking directory of "
111 rc = PTR_ERR(lower_dir_dentry);
114 rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
115 ecryptfs_dentry, mode, nd);
117 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
118 "rc = [%d]\n", __func__, rc);
121 rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
122 directory_inode->i_sb, 0);
124 ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n");
127 fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
128 fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode);
130 unlock_dir(lower_dir_dentry);
137 * @ecryptfs_dentry: the eCryptfs dentry
139 * This is the code which will grow the file to its correct size.
141 static int grow_file(struct dentry *ecryptfs_dentry)
143 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
144 struct file fake_file;
145 struct ecryptfs_file_info tmp_file_info;
146 char zero_virt[] = { 0x00 };
149 memset(&fake_file, 0, sizeof(fake_file));
150 fake_file.f_path.dentry = ecryptfs_dentry;
151 memset(&tmp_file_info, 0, sizeof(tmp_file_info));
152 ecryptfs_set_file_private(&fake_file, &tmp_file_info);
153 ecryptfs_set_file_lower(
155 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file);
156 rc = ecryptfs_write(&fake_file, zero_virt, 0, 1);
157 i_size_write(ecryptfs_inode, 0);
158 rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode);
159 ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat.flags |=
165 * ecryptfs_initialize_file
167 * Cause the file to be changed from a basic empty file to an ecryptfs
168 * file with a header and first data page.
170 * Returns zero on success
172 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
174 struct ecryptfs_crypt_stat *crypt_stat =
175 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
178 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
179 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
180 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
183 crypt_stat->flags |= ECRYPTFS_NEW_FILE;
184 ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
185 rc = ecryptfs_new_file_context(ecryptfs_dentry);
187 ecryptfs_printk(KERN_ERR, "Error creating new file "
188 "context; rc = [%d]\n", rc);
191 if (!ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->lower_file) {
192 rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
194 printk(KERN_ERR "%s: Error attempting to initialize "
195 "the persistent file for the dentry with name "
196 "[%s]; rc = [%d]\n", __func__,
197 ecryptfs_dentry->d_name.name, rc);
201 rc = ecryptfs_write_metadata(ecryptfs_dentry);
203 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
206 rc = grow_file(ecryptfs_dentry);
208 printk(KERN_ERR "Error growing file; rc = [%d]\n", rc);
215 * @dir: The inode of the directory in which to create the file.
216 * @dentry: The eCryptfs dentry
217 * @mode: The mode of the new file.
220 * Creates a new file.
222 * Returns zero on success; non-zero on error condition
225 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
226 int mode, struct nameidata *nd)
230 /* ecryptfs_do_create() calls ecryptfs_interpose() */
231 rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
233 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
234 "lower filesystem\n");
237 /* At this point, a file exists on "disk"; we need to make sure
238 * that this on disk file is prepared to be an ecryptfs file */
239 rc = ecryptfs_initialize_file(ecryptfs_dentry);
245 * ecryptfs_lookup_and_interpose_lower - Perform a lookup
247 int ecryptfs_lookup_and_interpose_lower(struct dentry *ecryptfs_dentry,
248 struct dentry *lower_dentry,
249 struct inode *ecryptfs_dir_inode,
250 struct nameidata *ecryptfs_nd)
252 struct dentry *lower_dir_dentry;
253 struct vfsmount *lower_mnt;
254 struct inode *lower_inode;
255 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
256 struct ecryptfs_crypt_stat *crypt_stat;
257 char *page_virt = NULL;
261 lower_dir_dentry = lower_dentry->d_parent;
262 lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(
263 ecryptfs_dentry->d_parent));
264 lower_inode = lower_dentry->d_inode;
265 fsstack_copy_attr_atime(ecryptfs_dir_inode, lower_dir_dentry->d_inode);
266 BUG_ON(!atomic_read(&lower_dentry->d_count));
267 ecryptfs_set_dentry_private(ecryptfs_dentry,
268 kmem_cache_alloc(ecryptfs_dentry_info_cache,
270 if (!ecryptfs_dentry_to_private(ecryptfs_dentry)) {
272 printk(KERN_ERR "%s: Out of memory whilst attempting "
273 "to allocate ecryptfs_dentry_info struct\n",
277 ecryptfs_set_dentry_lower(ecryptfs_dentry, lower_dentry);
278 ecryptfs_set_dentry_lower_mnt(ecryptfs_dentry, lower_mnt);
279 if (!lower_dentry->d_inode) {
280 /* We want to add because we couldn't find in lower */
281 d_add(ecryptfs_dentry, NULL);
284 rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
285 ecryptfs_dir_inode->i_sb,
286 ECRYPTFS_INTERPOSE_FLAG_D_ADD);
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 crypt_stat = &ecryptfs_inode_to_private(
319 ecryptfs_dentry->d_inode)->crypt_stat;
320 /* TODO: lock for crypt_stat comparison */
321 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
322 ecryptfs_set_default_sizes(crypt_stat);
323 rc = ecryptfs_read_and_validate_header_region(page_virt,
324 ecryptfs_dentry->d_inode);
326 memset(page_virt, 0, PAGE_CACHE_SIZE);
327 rc = ecryptfs_read_and_validate_xattr_region(page_virt,
333 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
335 mount_crypt_stat = &ecryptfs_superblock_to_private(
336 ecryptfs_dentry->d_sb)->mount_crypt_stat;
337 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
338 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
339 file_size = (crypt_stat->metadata_size
340 + i_size_read(lower_dentry->d_inode));
342 file_size = i_size_read(lower_dentry->d_inode);
344 file_size = get_unaligned_be64(page_virt);
346 i_size_write(ecryptfs_dentry->d_inode, (loff_t)file_size);
348 kmem_cache_free(ecryptfs_header_cache_2, page_virt);
352 d_drop(ecryptfs_dentry);
359 * @ecryptfs_dir_inode: The eCryptfs directory inode
360 * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
361 * @ecryptfs_nd: nameidata; may be NULL
363 * Find a file on disk. If the file does not exist, then we'll add it to the
364 * dentry cache and continue on to read it from the disk.
366 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
367 struct dentry *ecryptfs_dentry,
368 struct nameidata *ecryptfs_nd)
370 char *encrypted_and_encoded_name = NULL;
371 size_t encrypted_and_encoded_name_size;
372 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
373 struct dentry *lower_dir_dentry, *lower_dentry;
376 ecryptfs_dentry->d_op = &ecryptfs_dops;
377 if ((ecryptfs_dentry->d_name.len == 1
378 && !strcmp(ecryptfs_dentry->d_name.name, "."))
379 || (ecryptfs_dentry->d_name.len == 2
380 && !strcmp(ecryptfs_dentry->d_name.name, ".."))) {
383 lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
384 mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
385 lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name,
387 ecryptfs_dentry->d_name.len);
388 mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
389 if (IS_ERR(lower_dentry)) {
390 rc = PTR_ERR(lower_dentry);
391 printk(KERN_ERR "%s: lookup_one_len() returned [%d] on "
392 "lower_dentry = [%s]\n", __func__, rc,
393 ecryptfs_dentry->d_name.name);
396 if (lower_dentry->d_inode)
397 goto lookup_and_interpose;
398 mount_crypt_stat = &ecryptfs_superblock_to_private(
399 ecryptfs_dentry->d_sb)->mount_crypt_stat;
400 if (!(mount_crypt_stat
401 && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)))
402 goto lookup_and_interpose;
404 rc = ecryptfs_encrypt_and_encode_filename(
405 &encrypted_and_encoded_name, &encrypted_and_encoded_name_size,
406 NULL, mount_crypt_stat, ecryptfs_dentry->d_name.name,
407 ecryptfs_dentry->d_name.len);
409 printk(KERN_ERR "%s: Error attempting to encrypt and encode "
410 "filename; rc = [%d]\n", __func__, rc);
413 mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
414 lower_dentry = lookup_one_len(encrypted_and_encoded_name,
416 encrypted_and_encoded_name_size - 1);
417 mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
418 if (IS_ERR(lower_dentry)) {
419 rc = PTR_ERR(lower_dentry);
420 printk(KERN_ERR "%s: lookup_one_len() returned [%d] on "
421 "lower_dentry = [%s]\n", __func__, rc,
422 encrypted_and_encoded_name);
425 lookup_and_interpose:
426 rc = ecryptfs_lookup_and_interpose_lower(ecryptfs_dentry, lower_dentry,
431 d_drop(ecryptfs_dentry);
433 kfree(encrypted_and_encoded_name);
437 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
438 struct dentry *new_dentry)
440 struct dentry *lower_old_dentry;
441 struct dentry *lower_new_dentry;
442 struct dentry *lower_dir_dentry;
446 file_size_save = i_size_read(old_dentry->d_inode);
447 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
448 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
449 dget(lower_old_dentry);
450 dget(lower_new_dentry);
451 lower_dir_dentry = lock_parent(lower_new_dentry);
452 rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
454 if (rc || !lower_new_dentry->d_inode)
456 rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
459 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
460 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
461 old_dentry->d_inode->i_nlink =
462 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
463 i_size_write(new_dentry->d_inode, file_size_save);
465 unlock_dir(lower_dir_dentry);
466 dput(lower_new_dentry);
467 dput(lower_old_dentry);
471 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
474 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
475 struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
476 struct dentry *lower_dir_dentry;
479 lower_dir_dentry = lock_parent(lower_dentry);
480 rc = vfs_unlink(lower_dir_inode, lower_dentry);
482 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
485 fsstack_copy_attr_times(dir, lower_dir_inode);
486 dentry->d_inode->i_nlink =
487 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
488 dentry->d_inode->i_ctime = dir->i_ctime;
491 unlock_dir(lower_dir_dentry);
496 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
500 struct dentry *lower_dentry;
501 struct dentry *lower_dir_dentry;
502 char *encoded_symname;
503 size_t encoded_symlen;
504 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
506 lower_dentry = ecryptfs_dentry_to_lower(dentry);
508 lower_dir_dentry = lock_parent(lower_dentry);
509 mount_crypt_stat = &ecryptfs_superblock_to_private(
510 dir->i_sb)->mount_crypt_stat;
511 rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
514 mount_crypt_stat, symname,
518 rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
520 kfree(encoded_symname);
521 if (rc || !lower_dentry->d_inode)
523 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
526 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
527 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
529 unlock_dir(lower_dir_dentry);
531 if (!dentry->d_inode)
536 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
539 struct dentry *lower_dentry;
540 struct dentry *lower_dir_dentry;
542 lower_dentry = ecryptfs_dentry_to_lower(dentry);
543 lower_dir_dentry = lock_parent(lower_dentry);
544 rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
545 if (rc || !lower_dentry->d_inode)
547 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
550 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
551 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
552 dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
554 unlock_dir(lower_dir_dentry);
555 if (!dentry->d_inode)
560 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
562 struct dentry *lower_dentry;
563 struct dentry *lower_dir_dentry;
566 lower_dentry = ecryptfs_dentry_to_lower(dentry);
568 lower_dir_dentry = lock_parent(lower_dentry);
570 rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
573 d_delete(lower_dentry);
574 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
575 dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
576 unlock_dir(lower_dir_dentry);
584 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
587 struct dentry *lower_dentry;
588 struct dentry *lower_dir_dentry;
590 lower_dentry = ecryptfs_dentry_to_lower(dentry);
591 lower_dir_dentry = lock_parent(lower_dentry);
592 rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
593 if (rc || !lower_dentry->d_inode)
595 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
598 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
599 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
601 unlock_dir(lower_dir_dentry);
602 if (!dentry->d_inode)
608 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
609 struct inode *new_dir, struct dentry *new_dentry)
612 struct dentry *lower_old_dentry;
613 struct dentry *lower_new_dentry;
614 struct dentry *lower_old_dir_dentry;
615 struct dentry *lower_new_dir_dentry;
616 struct dentry *trap = NULL;
618 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
619 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
620 dget(lower_old_dentry);
621 dget(lower_new_dentry);
622 lower_old_dir_dentry = dget_parent(lower_old_dentry);
623 lower_new_dir_dentry = dget_parent(lower_new_dentry);
624 trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
625 /* source should not be ancestor of target */
626 if (trap == lower_old_dentry) {
630 /* target should not be ancestor of source */
631 if (trap == lower_new_dentry) {
635 rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
636 lower_new_dir_dentry->d_inode, lower_new_dentry);
639 fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode);
640 if (new_dir != old_dir)
641 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode);
643 unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
644 dput(lower_new_dentry->d_parent);
645 dput(lower_old_dentry->d_parent);
646 dput(lower_new_dentry);
647 dput(lower_old_dentry);
651 static int ecryptfs_readlink_lower(struct dentry *dentry, char **buf,
654 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
656 size_t lower_bufsiz = PATH_MAX;
660 lower_buf = kmalloc(lower_bufsiz, GFP_KERNEL);
667 rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
668 (char __user *)lower_buf,
674 rc = ecryptfs_decode_and_decrypt_filename(buf, bufsiz, dentry,
675 lower_buf, lower_bufsiz);
682 ecryptfs_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
685 size_t kbufsiz, copied;
688 rc = ecryptfs_readlink_lower(dentry, &kbuf, &kbufsiz);
691 copied = min_t(size_t, bufsiz, kbufsiz);
692 rc = copy_to_user(buf, kbuf, copied) ? -EFAULT : copied;
694 fsstack_copy_attr_atime(dentry->d_inode,
695 ecryptfs_dentry_to_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);
709 buf = ERR_PTR(-ENOMEM);
714 rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
722 nd_set_link(nd, buf);
727 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
729 char *buf = 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 = ecryptfs_lower_header_size(crypt_stat);
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 * @ia: Address of the ecryptfs inode's attributes
769 * @lower_ia: Address of the lower inode's attributes
771 * Function to handle truncations modifying the size of the file. Note
772 * that the file sizes are interpolated. When expanding, we are simply
773 * writing strings of 0's out. When truncating, we truncate the upper
774 * inode and update the lower_ia according to the page index
775 * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
776 * the caller must use lower_ia in a call to notify_change() to perform
777 * the truncation of the lower inode.
779 * Returns zero on success; non-zero otherwise
781 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
782 struct iattr *lower_ia)
785 struct inode *inode = dentry->d_inode;
786 struct dentry *lower_dentry;
787 struct file fake_ecryptfs_file;
788 struct ecryptfs_crypt_stat *crypt_stat;
789 loff_t i_size = i_size_read(inode);
790 loff_t lower_size_before_truncate;
791 loff_t lower_size_after_truncate;
793 if (unlikely((ia->ia_size == i_size))) {
794 lower_ia->ia_valid &= ~ATTR_SIZE;
797 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
798 /* Set up a fake ecryptfs file, this is used to interface with
799 * the file in the underlying filesystem so that the
800 * truncation has an effect there as well. */
801 memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
802 fake_ecryptfs_file.f_path.dentry = dentry;
803 /* Released at out_free: label */
804 ecryptfs_set_file_private(&fake_ecryptfs_file,
805 kmem_cache_alloc(ecryptfs_file_info_cache,
807 if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
811 lower_dentry = ecryptfs_dentry_to_lower(dentry);
812 ecryptfs_set_file_lower(
814 ecryptfs_inode_to_private(dentry->d_inode)->lower_file);
815 /* Switch on growing or shrinking file */
816 if (ia->ia_size > i_size) {
817 char zero[] = { 0x00 };
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(&fake_ecryptfs_file, 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));
834 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
835 rc = vmtruncate(inode, ia->ia_size);
838 lower_ia->ia_size = ia->ia_size;
839 lower_ia->ia_valid |= ATTR_SIZE;
845 zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
850 rc = ecryptfs_write(&fake_ecryptfs_file, zeros_virt,
851 ia->ia_size, num_zeros);
854 printk(KERN_ERR "Error attempting to zero out "
855 "the remainder of the end page on "
856 "reducing truncate; rc = [%d]\n", rc);
860 vmtruncate(inode, ia->ia_size);
861 rc = ecryptfs_write_inode_size_to_metadata(inode);
863 printk(KERN_ERR "Problem with "
864 "ecryptfs_write_inode_size_to_metadata; "
868 /* We are reducing the size of the ecryptfs file, and need to
869 * know if we need to reduce the size of the lower file. */
870 lower_size_before_truncate =
871 upper_size_to_lower_size(crypt_stat, i_size);
872 lower_size_after_truncate =
873 upper_size_to_lower_size(crypt_stat, ia->ia_size);
874 if (lower_size_after_truncate < lower_size_before_truncate) {
875 lower_ia->ia_size = lower_size_after_truncate;
876 lower_ia->ia_valid |= ATTR_SIZE;
878 lower_ia->ia_valid &= ~ATTR_SIZE;
881 if (ecryptfs_file_to_private(&fake_ecryptfs_file))
882 kmem_cache_free(ecryptfs_file_info_cache,
883 ecryptfs_file_to_private(&fake_ecryptfs_file));
890 * @dentry: The ecryptfs layer dentry
891 * @new_length: The length to expand the file to
893 * Simple function that handles the truncation of an eCryptfs inode and
894 * its corresponding lower inode.
896 * Returns zero on success; non-zero otherwise
898 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
900 struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
901 struct iattr lower_ia = { .ia_valid = 0 };
904 rc = truncate_upper(dentry, &ia, &lower_ia);
905 if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
906 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
908 mutex_lock(&lower_dentry->d_inode->i_mutex);
909 rc = notify_change(lower_dentry, &lower_ia);
910 mutex_unlock(&lower_dentry->d_inode->i_mutex);
916 ecryptfs_permission(struct inode *inode, int mask)
918 return inode_permission(ecryptfs_inode_to_lower(inode), mask);
923 * @dentry: dentry handle to the inode to modify
924 * @ia: Structure with flags of what to change and values
926 * Updates the metadata of an inode. If the update is to the size
927 * i.e. truncation, then ecryptfs_truncate will handle the size modification
928 * of both the ecryptfs inode and the lower inode.
930 * All other metadata changes will be passed right to the lower filesystem,
931 * and we will just update our inode to look like the lower.
933 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
936 struct dentry *lower_dentry;
937 struct iattr lower_ia;
939 struct inode *lower_inode;
940 struct ecryptfs_crypt_stat *crypt_stat;
942 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
943 if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
944 ecryptfs_init_crypt_stat(crypt_stat);
945 inode = dentry->d_inode;
946 lower_inode = ecryptfs_inode_to_lower(inode);
947 lower_dentry = ecryptfs_dentry_to_lower(dentry);
948 mutex_lock(&crypt_stat->cs_mutex);
949 if (S_ISDIR(dentry->d_inode->i_mode))
950 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
951 else if (S_ISREG(dentry->d_inode->i_mode)
952 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
953 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
954 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
956 mount_crypt_stat = &ecryptfs_superblock_to_private(
957 dentry->d_sb)->mount_crypt_stat;
958 rc = ecryptfs_read_metadata(dentry);
960 if (!(mount_crypt_stat->flags
961 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
963 printk(KERN_WARNING "Either the lower file "
964 "is not in a valid eCryptfs format, "
965 "or the key could not be retrieved. "
966 "Plaintext passthrough mode is not "
967 "enabled; returning -EIO\n");
968 mutex_unlock(&crypt_stat->cs_mutex);
972 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
975 mutex_unlock(&crypt_stat->cs_mutex);
976 memcpy(&lower_ia, ia, sizeof(lower_ia));
977 if (ia->ia_valid & ATTR_FILE)
978 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
979 if (ia->ia_valid & ATTR_SIZE) {
980 rc = truncate_upper(dentry, ia, &lower_ia);
986 * mode change is for clearing setuid/setgid bits. Allow lower fs
987 * to interpret this in its own way.
989 if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
990 lower_ia.ia_valid &= ~ATTR_MODE;
992 mutex_lock(&lower_dentry->d_inode->i_mutex);
993 rc = notify_change(lower_dentry, &lower_ia);
994 mutex_unlock(&lower_dentry->d_inode->i_mutex);
996 fsstack_copy_attr_all(inode, lower_inode);
1000 int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
1003 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
1006 mount_crypt_stat = &ecryptfs_superblock_to_private(
1007 dentry->d_sb)->mount_crypt_stat;
1008 generic_fillattr(dentry->d_inode, stat);
1009 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
1013 rc = ecryptfs_readlink_lower(dentry, &target, &targetsiz);
1016 stat->size = targetsiz;
1022 int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
1025 struct kstat lower_stat;
1028 rc = vfs_getattr(ecryptfs_dentry_to_lower_mnt(dentry),
1029 ecryptfs_dentry_to_lower(dentry), &lower_stat);
1031 generic_fillattr(dentry->d_inode, stat);
1032 stat->blocks = lower_stat.blocks;
1038 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
1039 size_t size, int flags)
1042 struct dentry *lower_dentry;
1044 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1045 if (!lower_dentry->d_inode->i_op->setxattr) {
1049 mutex_lock(&lower_dentry->d_inode->i_mutex);
1050 rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
1052 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1058 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
1059 void *value, size_t size)
1063 if (!lower_dentry->d_inode->i_op->getxattr) {
1067 mutex_lock(&lower_dentry->d_inode->i_mutex);
1068 rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
1070 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1076 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
1079 return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
1084 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1087 struct dentry *lower_dentry;
1089 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1090 if (!lower_dentry->d_inode->i_op->listxattr) {
1094 mutex_lock(&lower_dentry->d_inode->i_mutex);
1095 rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1096 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1101 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1104 struct dentry *lower_dentry;
1106 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1107 if (!lower_dentry->d_inode->i_op->removexattr) {
1111 mutex_lock(&lower_dentry->d_inode->i_mutex);
1112 rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1113 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1118 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
1120 if ((ecryptfs_inode_to_lower(inode)
1121 == (struct inode *)candidate_lower_inode))
1127 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1129 ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1133 const struct inode_operations ecryptfs_symlink_iops = {
1134 .readlink = ecryptfs_readlink,
1135 .follow_link = ecryptfs_follow_link,
1136 .put_link = ecryptfs_put_link,
1137 .permission = ecryptfs_permission,
1138 .setattr = ecryptfs_setattr,
1139 .getattr = ecryptfs_getattr_link,
1140 .setxattr = ecryptfs_setxattr,
1141 .getxattr = ecryptfs_getxattr,
1142 .listxattr = ecryptfs_listxattr,
1143 .removexattr = ecryptfs_removexattr
1146 const struct inode_operations ecryptfs_dir_iops = {
1147 .create = ecryptfs_create,
1148 .lookup = ecryptfs_lookup,
1149 .link = ecryptfs_link,
1150 .unlink = ecryptfs_unlink,
1151 .symlink = ecryptfs_symlink,
1152 .mkdir = ecryptfs_mkdir,
1153 .rmdir = ecryptfs_rmdir,
1154 .mknod = ecryptfs_mknod,
1155 .rename = ecryptfs_rename,
1156 .permission = ecryptfs_permission,
1157 .setattr = ecryptfs_setattr,
1158 .setxattr = ecryptfs_setxattr,
1159 .getxattr = ecryptfs_getxattr,
1160 .listxattr = ecryptfs_listxattr,
1161 .removexattr = ecryptfs_removexattr
1164 const struct inode_operations ecryptfs_main_iops = {
1165 .permission = ecryptfs_permission,
1166 .setattr = ecryptfs_setattr,
1167 .getattr = ecryptfs_getattr,
1168 .setxattr = ecryptfs_setxattr,
1169 .getxattr = ecryptfs_getxattr,
1170 .listxattr = ecryptfs_listxattr,
1171 .removexattr = ecryptfs_removexattr