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 <asm/unaligned.h>
36 #include "ecryptfs_kernel.h"
38 static struct dentry *lock_parent(struct dentry *dentry)
42 dir = dget_parent(dentry);
43 mutex_lock_nested(&(dir->d_inode->i_mutex), I_MUTEX_PARENT);
47 static void unlock_dir(struct dentry *dir)
49 mutex_unlock(&dir->d_inode->i_mutex);
54 * ecryptfs_create_underlying_file
55 * @lower_dir_inode: inode of the parent in the lower fs of the new file
56 * @dentry: New file's dentry
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 char zero_virt[] = { 0x00 };
148 rc = ecryptfs_write(ecryptfs_inode, zero_virt, 0, 1);
149 i_size_write(ecryptfs_inode, 0);
150 rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode);
151 ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat.flags |=
157 * ecryptfs_initialize_file
159 * Cause the file to be changed from a basic empty file to an ecryptfs
160 * file with a header and first data page.
162 * Returns zero on success
164 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
166 struct ecryptfs_crypt_stat *crypt_stat =
167 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
170 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
171 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
172 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
175 crypt_stat->flags |= ECRYPTFS_NEW_FILE;
176 ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
177 rc = ecryptfs_new_file_context(ecryptfs_dentry);
179 ecryptfs_printk(KERN_ERR, "Error creating new file "
180 "context; rc = [%d]\n", rc);
183 if (!ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->lower_file) {
184 rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
186 printk(KERN_ERR "%s: Error attempting to initialize "
187 "the persistent file for the dentry with name "
188 "[%s]; rc = [%d]\n", __func__,
189 ecryptfs_dentry->d_name.name, rc);
193 rc = ecryptfs_write_metadata(ecryptfs_dentry);
195 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
198 rc = grow_file(ecryptfs_dentry);
200 printk(KERN_ERR "Error growing file; rc = [%d]\n", rc);
207 * @dir: The inode of the directory in which to create the file.
208 * @dentry: The eCryptfs dentry
209 * @mode: The mode of the new file.
212 * Creates a new file.
214 * Returns zero on success; non-zero on error condition
217 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
218 int mode, struct nameidata *nd)
222 /* ecryptfs_do_create() calls ecryptfs_interpose() */
223 rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
225 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
226 "lower filesystem\n");
229 /* At this point, a file exists on "disk"; we need to make sure
230 * that this on disk file is prepared to be an ecryptfs file */
231 rc = ecryptfs_initialize_file(ecryptfs_dentry);
237 * ecryptfs_lookup_and_interpose_lower - Perform a lookup
239 int ecryptfs_lookup_and_interpose_lower(struct dentry *ecryptfs_dentry,
240 struct dentry *lower_dentry,
241 struct inode *ecryptfs_dir_inode,
242 struct nameidata *ecryptfs_nd)
244 struct dentry *lower_dir_dentry;
245 struct vfsmount *lower_mnt;
246 struct inode *lower_inode;
247 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
248 struct ecryptfs_crypt_stat *crypt_stat;
249 char *page_virt = NULL;
253 lower_dir_dentry = lower_dentry->d_parent;
254 lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(
255 ecryptfs_dentry->d_parent));
256 lower_inode = lower_dentry->d_inode;
257 fsstack_copy_attr_atime(ecryptfs_dir_inode, lower_dir_dentry->d_inode);
258 BUG_ON(!atomic_read(&lower_dentry->d_count));
259 ecryptfs_set_dentry_private(ecryptfs_dentry,
260 kmem_cache_alloc(ecryptfs_dentry_info_cache,
262 if (!ecryptfs_dentry_to_private(ecryptfs_dentry)) {
264 printk(KERN_ERR "%s: Out of memory whilst attempting "
265 "to allocate ecryptfs_dentry_info struct\n",
269 ecryptfs_set_dentry_lower(ecryptfs_dentry, lower_dentry);
270 ecryptfs_set_dentry_lower_mnt(ecryptfs_dentry, lower_mnt);
271 if (!lower_dentry->d_inode) {
272 /* We want to add because we couldn't find in lower */
273 d_add(ecryptfs_dentry, NULL);
276 rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
277 ecryptfs_dir_inode->i_sb,
278 ECRYPTFS_INTERPOSE_FLAG_D_ADD);
280 printk(KERN_ERR "%s: Error interposing; rc = [%d]\n",
284 if (S_ISDIR(lower_inode->i_mode))
286 if (S_ISLNK(lower_inode->i_mode))
288 if (special_file(lower_inode->i_mode))
292 /* Released in this function */
293 page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2, GFP_USER);
295 printk(KERN_ERR "%s: Cannot kmem_cache_zalloc() a page\n",
300 if (!ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->lower_file) {
301 rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
303 printk(KERN_ERR "%s: Error attempting to initialize "
304 "the persistent file for the dentry with name "
305 "[%s]; rc = [%d]\n", __func__,
306 ecryptfs_dentry->d_name.name, rc);
310 crypt_stat = &ecryptfs_inode_to_private(
311 ecryptfs_dentry->d_inode)->crypt_stat;
312 /* TODO: lock for crypt_stat comparison */
313 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
314 ecryptfs_set_default_sizes(crypt_stat);
315 rc = ecryptfs_read_and_validate_header_region(page_virt,
316 ecryptfs_dentry->d_inode);
318 memset(page_virt, 0, PAGE_CACHE_SIZE);
319 rc = ecryptfs_read_and_validate_xattr_region(page_virt,
325 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
327 mount_crypt_stat = &ecryptfs_superblock_to_private(
328 ecryptfs_dentry->d_sb)->mount_crypt_stat;
329 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
330 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
331 file_size = (crypt_stat->metadata_size
332 + i_size_read(lower_dentry->d_inode));
334 file_size = i_size_read(lower_dentry->d_inode);
336 file_size = get_unaligned_be64(page_virt);
338 i_size_write(ecryptfs_dentry->d_inode, (loff_t)file_size);
340 kmem_cache_free(ecryptfs_header_cache_2, page_virt);
345 d_drop(ecryptfs_dentry);
351 * ecryptfs_new_lower_dentry
352 * @ename: The name of the new dentry.
353 * @lower_dir_dentry: Parent directory of the new dentry.
354 * @nd: nameidata from last lookup.
356 * Create a new dentry or get it from lower parent dir.
358 static struct dentry *
359 ecryptfs_new_lower_dentry(struct qstr *name, struct dentry *lower_dir_dentry,
360 struct nameidata *nd)
362 struct dentry *new_dentry;
364 struct inode *lower_dir_inode;
366 lower_dir_inode = lower_dir_dentry->d_inode;
368 tmp = d_alloc(lower_dir_dentry, name);
370 return ERR_PTR(-ENOMEM);
372 mutex_lock(&lower_dir_inode->i_mutex);
373 new_dentry = lower_dir_inode->i_op->lookup(lower_dir_inode, tmp, nd);
374 mutex_unlock(&lower_dir_inode->i_mutex);
386 * ecryptfs_lookup_one_lower
387 * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
388 * @lower_dir_dentry: lower parent directory
390 * Get the lower dentry from vfs. If lower dentry does not exist yet,
393 static struct dentry *
394 ecryptfs_lookup_one_lower(struct dentry *ecryptfs_dentry,
395 struct dentry *lower_dir_dentry)
398 struct vfsmount *lower_mnt;
402 name = &ecryptfs_dentry->d_name;
403 lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(
404 ecryptfs_dentry->d_parent));
405 err = vfs_path_lookup(lower_dir_dentry, lower_mnt, name->name , 0, &nd);
409 /* we dont need the mount */
411 return nd.path.dentry;
416 /* create a new lower dentry */
417 return ecryptfs_new_lower_dentry(name, lower_dir_dentry, &nd);
422 * @ecryptfs_dir_inode: The eCryptfs directory inode
423 * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
424 * @ecryptfs_nd: nameidata; may be NULL
426 * Find a file on disk. If the file does not exist, then we'll add it to the
427 * dentry cache and continue on to read it from the disk.
429 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
430 struct dentry *ecryptfs_dentry,
431 struct nameidata *ecryptfs_nd)
433 char *encrypted_and_encoded_name = NULL;
434 size_t encrypted_and_encoded_name_size;
435 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
436 struct dentry *lower_dir_dentry, *lower_dentry;
439 ecryptfs_dentry->d_op = &ecryptfs_dops;
440 if ((ecryptfs_dentry->d_name.len == 1
441 && !strcmp(ecryptfs_dentry->d_name.name, "."))
442 || (ecryptfs_dentry->d_name.len == 2
443 && !strcmp(ecryptfs_dentry->d_name.name, ".."))) {
446 lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
448 lower_dentry = ecryptfs_lookup_one_lower(ecryptfs_dentry,
450 if (IS_ERR(lower_dentry)) {
451 rc = PTR_ERR(lower_dentry);
452 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_lower() returned "
453 "[%d] on lower_dentry = [%s]\n", __func__, rc,
454 encrypted_and_encoded_name);
457 if (lower_dentry->d_inode)
458 goto lookup_and_interpose;
459 mount_crypt_stat = &ecryptfs_superblock_to_private(
460 ecryptfs_dentry->d_sb)->mount_crypt_stat;
461 if (!(mount_crypt_stat
462 && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)))
463 goto lookup_and_interpose;
465 rc = ecryptfs_encrypt_and_encode_filename(
466 &encrypted_and_encoded_name, &encrypted_and_encoded_name_size,
467 NULL, mount_crypt_stat, ecryptfs_dentry->d_name.name,
468 ecryptfs_dentry->d_name.len);
470 printk(KERN_ERR "%s: Error attempting to encrypt and encode "
471 "filename; rc = [%d]\n", __func__, rc);
474 lower_dentry = ecryptfs_lookup_one_lower(ecryptfs_dentry,
476 if (IS_ERR(lower_dentry)) {
477 rc = PTR_ERR(lower_dentry);
478 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_lower() returned "
479 "[%d] on lower_dentry = [%s]\n", __func__, rc,
480 encrypted_and_encoded_name);
483 lookup_and_interpose:
484 rc = ecryptfs_lookup_and_interpose_lower(ecryptfs_dentry, lower_dentry,
489 d_drop(ecryptfs_dentry);
491 kfree(encrypted_and_encoded_name);
495 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
496 struct dentry *new_dentry)
498 struct dentry *lower_old_dentry;
499 struct dentry *lower_new_dentry;
500 struct dentry *lower_dir_dentry;
504 file_size_save = i_size_read(old_dentry->d_inode);
505 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
506 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
507 dget(lower_old_dentry);
508 dget(lower_new_dentry);
509 lower_dir_dentry = lock_parent(lower_new_dentry);
510 rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
512 if (rc || !lower_new_dentry->d_inode)
514 rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
517 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
518 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
519 old_dentry->d_inode->i_nlink =
520 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
521 i_size_write(new_dentry->d_inode, file_size_save);
523 unlock_dir(lower_dir_dentry);
524 dput(lower_new_dentry);
525 dput(lower_old_dentry);
529 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
532 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
533 struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
534 struct dentry *lower_dir_dentry;
537 lower_dir_dentry = lock_parent(lower_dentry);
538 rc = vfs_unlink(lower_dir_inode, lower_dentry);
540 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
543 fsstack_copy_attr_times(dir, lower_dir_inode);
544 dentry->d_inode->i_nlink =
545 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
546 dentry->d_inode->i_ctime = dir->i_ctime;
549 unlock_dir(lower_dir_dentry);
554 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
558 struct dentry *lower_dentry;
559 struct dentry *lower_dir_dentry;
560 char *encoded_symname;
561 size_t encoded_symlen;
562 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
564 lower_dentry = ecryptfs_dentry_to_lower(dentry);
566 lower_dir_dentry = lock_parent(lower_dentry);
567 mount_crypt_stat = &ecryptfs_superblock_to_private(
568 dir->i_sb)->mount_crypt_stat;
569 rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
572 mount_crypt_stat, symname,
576 rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
578 kfree(encoded_symname);
579 if (rc || !lower_dentry->d_inode)
581 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
584 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
585 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
587 unlock_dir(lower_dir_dentry);
589 if (!dentry->d_inode)
594 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
597 struct dentry *lower_dentry;
598 struct dentry *lower_dir_dentry;
600 lower_dentry = ecryptfs_dentry_to_lower(dentry);
601 lower_dir_dentry = lock_parent(lower_dentry);
602 rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
603 if (rc || !lower_dentry->d_inode)
605 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
608 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
609 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
610 dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
612 unlock_dir(lower_dir_dentry);
613 if (!dentry->d_inode)
618 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
620 struct dentry *lower_dentry;
621 struct dentry *lower_dir_dentry;
624 lower_dentry = ecryptfs_dentry_to_lower(dentry);
626 lower_dir_dentry = lock_parent(lower_dentry);
628 rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
631 d_delete(lower_dentry);
632 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
633 dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
634 unlock_dir(lower_dir_dentry);
642 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
645 struct dentry *lower_dentry;
646 struct dentry *lower_dir_dentry;
648 lower_dentry = ecryptfs_dentry_to_lower(dentry);
649 lower_dir_dentry = lock_parent(lower_dentry);
650 rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
651 if (rc || !lower_dentry->d_inode)
653 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
656 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
657 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
659 unlock_dir(lower_dir_dentry);
660 if (!dentry->d_inode)
666 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
667 struct inode *new_dir, struct dentry *new_dentry)
670 struct dentry *lower_old_dentry;
671 struct dentry *lower_new_dentry;
672 struct dentry *lower_old_dir_dentry;
673 struct dentry *lower_new_dir_dentry;
674 struct dentry *trap = NULL;
676 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
677 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
678 dget(lower_old_dentry);
679 dget(lower_new_dentry);
680 lower_old_dir_dentry = dget_parent(lower_old_dentry);
681 lower_new_dir_dentry = dget_parent(lower_new_dentry);
682 trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
683 /* source should not be ancestor of target */
684 if (trap == lower_old_dentry) {
688 /* target should not be ancestor of source */
689 if (trap == lower_new_dentry) {
693 rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
694 lower_new_dir_dentry->d_inode, lower_new_dentry);
697 fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode);
698 if (new_dir != old_dir)
699 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode);
701 unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
702 dput(lower_new_dentry->d_parent);
703 dput(lower_old_dentry->d_parent);
704 dput(lower_new_dentry);
705 dput(lower_old_dentry);
709 static int ecryptfs_readlink_lower(struct dentry *dentry, char **buf,
712 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
714 size_t lower_bufsiz = PATH_MAX;
718 lower_buf = kmalloc(lower_bufsiz, GFP_KERNEL);
725 rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
726 (char __user *)lower_buf,
732 rc = ecryptfs_decode_and_decrypt_filename(buf, bufsiz, dentry,
733 lower_buf, lower_bufsiz);
740 ecryptfs_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
743 size_t kbufsiz, copied;
746 rc = ecryptfs_readlink_lower(dentry, &kbuf, &kbufsiz);
749 copied = min_t(size_t, bufsiz, kbufsiz);
750 rc = copy_to_user(buf, kbuf, copied) ? -EFAULT : copied;
752 fsstack_copy_attr_atime(dentry->d_inode,
753 ecryptfs_dentry_to_lower(dentry)->d_inode);
758 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
761 int len = PAGE_SIZE, rc;
764 /* Released in ecryptfs_put_link(); only release here on error */
765 buf = kmalloc(len, GFP_KERNEL);
767 buf = ERR_PTR(-ENOMEM);
772 rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
780 nd_set_link(nd, buf);
785 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
787 char *buf = nd_get_link(nd);
795 * upper_size_to_lower_size
796 * @crypt_stat: Crypt_stat associated with file
797 * @upper_size: Size of the upper file
799 * Calculate the required size of the lower file based on the
800 * specified size of the upper file. This calculation is based on the
801 * number of headers in the underlying file and the extent size.
803 * Returns Calculated size of the lower file.
806 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
811 lower_size = ecryptfs_lower_header_size(crypt_stat);
812 if (upper_size != 0) {
815 num_extents = upper_size >> crypt_stat->extent_shift;
816 if (upper_size & ~crypt_stat->extent_mask)
818 lower_size += (num_extents * crypt_stat->extent_size);
825 * @dentry: The ecryptfs layer dentry
826 * @ia: Address of the ecryptfs inode's attributes
827 * @lower_ia: Address of the lower inode's attributes
829 * Function to handle truncations modifying the size of the file. Note
830 * that the file sizes are interpolated. When expanding, we are simply
831 * writing strings of 0's out. When truncating, we truncate the upper
832 * inode and update the lower_ia according to the page index
833 * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
834 * the caller must use lower_ia in a call to notify_change() to perform
835 * the truncation of the lower inode.
837 * Returns zero on success; non-zero otherwise
839 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
840 struct iattr *lower_ia)
843 struct inode *inode = dentry->d_inode;
844 struct ecryptfs_crypt_stat *crypt_stat;
845 loff_t i_size = i_size_read(inode);
846 loff_t lower_size_before_truncate;
847 loff_t lower_size_after_truncate;
849 if (unlikely((ia->ia_size == i_size))) {
850 lower_ia->ia_valid &= ~ATTR_SIZE;
853 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
854 /* Switch on growing or shrinking file */
855 if (ia->ia_size > i_size) {
856 char zero[] = { 0x00 };
858 lower_ia->ia_valid &= ~ATTR_SIZE;
859 /* Write a single 0 at the last position of the file;
860 * this triggers code that will fill in 0's throughout
861 * the intermediate portion of the previous end of the
862 * file and the new and of the file */
863 rc = ecryptfs_write(inode, zero,
864 (ia->ia_size - 1), 1);
865 } else { /* ia->ia_size < i_size_read(inode) */
866 /* We're chopping off all the pages down to the page
867 * in which ia->ia_size is located. Fill in the end of
868 * that page from (ia->ia_size & ~PAGE_CACHE_MASK) to
869 * PAGE_CACHE_SIZE with zeros. */
870 size_t num_zeros = (PAGE_CACHE_SIZE
871 - (ia->ia_size & ~PAGE_CACHE_MASK));
875 * XXX(truncate) this should really happen at the begginning
876 * of ->setattr. But the code is too messy to that as part
877 * of a larger patch. ecryptfs is also totally missing out
878 * on the inode_change_ok check at the beginning of
879 * ->setattr while would include this.
881 rc = inode_newsize_ok(inode, ia->ia_size);
885 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
886 truncate_setsize(inode, ia->ia_size);
887 lower_ia->ia_size = ia->ia_size;
888 lower_ia->ia_valid |= ATTR_SIZE;
894 zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
899 rc = ecryptfs_write(inode, zeros_virt,
900 ia->ia_size, num_zeros);
903 printk(KERN_ERR "Error attempting to zero out "
904 "the remainder of the end page on "
905 "reducing truncate; rc = [%d]\n", rc);
909 truncate_setsize(inode, ia->ia_size);
910 rc = ecryptfs_write_inode_size_to_metadata(inode);
912 printk(KERN_ERR "Problem with "
913 "ecryptfs_write_inode_size_to_metadata; "
917 /* We are reducing the size of the ecryptfs file, and need to
918 * know if we need to reduce the size of the lower file. */
919 lower_size_before_truncate =
920 upper_size_to_lower_size(crypt_stat, i_size);
921 lower_size_after_truncate =
922 upper_size_to_lower_size(crypt_stat, ia->ia_size);
923 if (lower_size_after_truncate < lower_size_before_truncate) {
924 lower_ia->ia_size = lower_size_after_truncate;
925 lower_ia->ia_valid |= ATTR_SIZE;
927 lower_ia->ia_valid &= ~ATTR_SIZE;
935 * @dentry: The ecryptfs layer dentry
936 * @new_length: The length to expand the file to
938 * Simple function that handles the truncation of an eCryptfs inode and
939 * its corresponding lower inode.
941 * Returns zero on success; non-zero otherwise
943 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
945 struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
946 struct iattr lower_ia = { .ia_valid = 0 };
949 rc = truncate_upper(dentry, &ia, &lower_ia);
950 if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
951 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
953 mutex_lock(&lower_dentry->d_inode->i_mutex);
954 rc = notify_change(lower_dentry, &lower_ia);
955 mutex_unlock(&lower_dentry->d_inode->i_mutex);
961 ecryptfs_permission(struct inode *inode, int mask)
963 return inode_permission(ecryptfs_inode_to_lower(inode), mask);
968 * @dentry: dentry handle to the inode to modify
969 * @ia: Structure with flags of what to change and values
971 * Updates the metadata of an inode. If the update is to the size
972 * i.e. truncation, then ecryptfs_truncate will handle the size modification
973 * of both the ecryptfs inode and the lower inode.
975 * All other metadata changes will be passed right to the lower filesystem,
976 * and we will just update our inode to look like the lower.
978 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
981 struct dentry *lower_dentry;
982 struct iattr lower_ia;
984 struct inode *lower_inode;
985 struct ecryptfs_crypt_stat *crypt_stat;
987 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
988 if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
989 ecryptfs_init_crypt_stat(crypt_stat);
990 inode = dentry->d_inode;
991 lower_inode = ecryptfs_inode_to_lower(inode);
992 lower_dentry = ecryptfs_dentry_to_lower(dentry);
993 mutex_lock(&crypt_stat->cs_mutex);
994 if (S_ISDIR(dentry->d_inode->i_mode))
995 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
996 else if (S_ISREG(dentry->d_inode->i_mode)
997 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
998 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
999 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
1001 mount_crypt_stat = &ecryptfs_superblock_to_private(
1002 dentry->d_sb)->mount_crypt_stat;
1003 rc = ecryptfs_read_metadata(dentry);
1005 if (!(mount_crypt_stat->flags
1006 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
1008 printk(KERN_WARNING "Either the lower file "
1009 "is not in a valid eCryptfs format, "
1010 "or the key could not be retrieved. "
1011 "Plaintext passthrough mode is not "
1012 "enabled; returning -EIO\n");
1013 mutex_unlock(&crypt_stat->cs_mutex);
1017 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
1020 mutex_unlock(&crypt_stat->cs_mutex);
1021 memcpy(&lower_ia, ia, sizeof(lower_ia));
1022 if (ia->ia_valid & ATTR_FILE)
1023 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
1024 if (ia->ia_valid & ATTR_SIZE) {
1025 rc = truncate_upper(dentry, ia, &lower_ia);
1031 * mode change is for clearing setuid/setgid bits. Allow lower fs
1032 * to interpret this in its own way.
1034 if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
1035 lower_ia.ia_valid &= ~ATTR_MODE;
1037 mutex_lock(&lower_dentry->d_inode->i_mutex);
1038 rc = notify_change(lower_dentry, &lower_ia);
1039 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1041 fsstack_copy_attr_all(inode, lower_inode);
1045 int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
1048 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
1051 mount_crypt_stat = &ecryptfs_superblock_to_private(
1052 dentry->d_sb)->mount_crypt_stat;
1053 generic_fillattr(dentry->d_inode, stat);
1054 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
1058 rc = ecryptfs_readlink_lower(dentry, &target, &targetsiz);
1061 stat->size = targetsiz;
1067 int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
1070 struct kstat lower_stat;
1073 rc = vfs_getattr(ecryptfs_dentry_to_lower_mnt(dentry),
1074 ecryptfs_dentry_to_lower(dentry), &lower_stat);
1076 generic_fillattr(dentry->d_inode, stat);
1077 stat->blocks = lower_stat.blocks;
1083 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
1084 size_t size, int flags)
1087 struct dentry *lower_dentry;
1089 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1090 if (!lower_dentry->d_inode->i_op->setxattr) {
1094 mutex_lock(&lower_dentry->d_inode->i_mutex);
1095 rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
1097 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1103 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
1104 void *value, size_t size)
1108 if (!lower_dentry->d_inode->i_op->getxattr) {
1112 mutex_lock(&lower_dentry->d_inode->i_mutex);
1113 rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
1115 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1121 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
1124 return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
1129 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1132 struct dentry *lower_dentry;
1134 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1135 if (!lower_dentry->d_inode->i_op->listxattr) {
1139 mutex_lock(&lower_dentry->d_inode->i_mutex);
1140 rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1141 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1146 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1149 struct dentry *lower_dentry;
1151 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1152 if (!lower_dentry->d_inode->i_op->removexattr) {
1156 mutex_lock(&lower_dentry->d_inode->i_mutex);
1157 rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1158 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1163 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
1165 if ((ecryptfs_inode_to_lower(inode)
1166 == (struct inode *)candidate_lower_inode))
1172 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1174 ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1178 const struct inode_operations ecryptfs_symlink_iops = {
1179 .readlink = ecryptfs_readlink,
1180 .follow_link = ecryptfs_follow_link,
1181 .put_link = ecryptfs_put_link,
1182 .permission = ecryptfs_permission,
1183 .setattr = ecryptfs_setattr,
1184 .getattr = ecryptfs_getattr_link,
1185 .setxattr = ecryptfs_setxattr,
1186 .getxattr = ecryptfs_getxattr,
1187 .listxattr = ecryptfs_listxattr,
1188 .removexattr = ecryptfs_removexattr
1191 const struct inode_operations ecryptfs_dir_iops = {
1192 .create = ecryptfs_create,
1193 .lookup = ecryptfs_lookup,
1194 .link = ecryptfs_link,
1195 .unlink = ecryptfs_unlink,
1196 .symlink = ecryptfs_symlink,
1197 .mkdir = ecryptfs_mkdir,
1198 .rmdir = ecryptfs_rmdir,
1199 .mknod = ecryptfs_mknod,
1200 .rename = ecryptfs_rename,
1201 .permission = ecryptfs_permission,
1202 .setattr = ecryptfs_setattr,
1203 .setxattr = ecryptfs_setxattr,
1204 .getxattr = ecryptfs_getxattr,
1205 .listxattr = ecryptfs_listxattr,
1206 .removexattr = ecryptfs_removexattr
1209 const struct inode_operations ecryptfs_main_iops = {
1210 .permission = ecryptfs_permission,
1211 .setattr = ecryptfs_setattr,
1212 .getattr = ecryptfs_getattr,
1213 .setxattr = ecryptfs_setxattr,
1214 .getxattr = ecryptfs_getxattr,
1215 .listxattr = ecryptfs_listxattr,
1216 .removexattr = ecryptfs_removexattr