1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * eCryptfs: Linux filesystem encryption layer
5 * Copyright (C) 1997-2004 Erez Zadok
6 * Copyright (C) 2001-2004 Stony Brook University
7 * Copyright (C) 2004-2007 International Business Machines Corp.
8 * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
9 * Michael C. Thompsion <mcthomps@us.ibm.com>
12 #include <linux/file.h>
13 #include <linux/vmalloc.h>
14 #include <linux/pagemap.h>
15 #include <linux/dcache.h>
16 #include <linux/namei.h>
17 #include <linux/mount.h>
18 #include <linux/fs_stack.h>
19 #include <linux/slab.h>
20 #include <linux/xattr.h>
21 #include <asm/unaligned.h>
22 #include "ecryptfs_kernel.h"
24 static struct dentry *lock_parent(struct dentry *dentry)
28 dir = dget_parent(dentry);
29 inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
33 static void unlock_dir(struct dentry *dir)
35 inode_unlock(d_inode(dir));
39 static int ecryptfs_inode_test(struct inode *inode, void *lower_inode)
41 return ecryptfs_inode_to_lower(inode) == lower_inode;
44 static int ecryptfs_inode_set(struct inode *inode, void *opaque)
46 struct inode *lower_inode = opaque;
48 ecryptfs_set_inode_lower(inode, lower_inode);
49 fsstack_copy_attr_all(inode, lower_inode);
50 /* i_size will be overwritten for encrypted regular files */
51 fsstack_copy_inode_size(inode, lower_inode);
52 inode->i_ino = lower_inode->i_ino;
53 inode->i_mapping->a_ops = &ecryptfs_aops;
55 if (S_ISLNK(inode->i_mode))
56 inode->i_op = &ecryptfs_symlink_iops;
57 else if (S_ISDIR(inode->i_mode))
58 inode->i_op = &ecryptfs_dir_iops;
60 inode->i_op = &ecryptfs_main_iops;
62 if (S_ISDIR(inode->i_mode))
63 inode->i_fop = &ecryptfs_dir_fops;
64 else if (special_file(inode->i_mode))
65 init_special_inode(inode, inode->i_mode, inode->i_rdev);
67 inode->i_fop = &ecryptfs_main_fops;
72 static struct inode *__ecryptfs_get_inode(struct inode *lower_inode,
73 struct super_block *sb)
77 if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb))
78 return ERR_PTR(-EXDEV);
79 if (!igrab(lower_inode))
80 return ERR_PTR(-ESTALE);
81 inode = iget5_locked(sb, (unsigned long)lower_inode,
82 ecryptfs_inode_test, ecryptfs_inode_set,
86 return ERR_PTR(-EACCES);
88 if (!(inode->i_state & I_NEW))
94 struct inode *ecryptfs_get_inode(struct inode *lower_inode,
95 struct super_block *sb)
97 struct inode *inode = __ecryptfs_get_inode(lower_inode, sb);
99 if (!IS_ERR(inode) && (inode->i_state & I_NEW))
100 unlock_new_inode(inode);
107 * @lower_dentry: Existing dentry in the lower filesystem
108 * @dentry: ecryptfs' dentry
109 * @sb: ecryptfs's super_block
111 * Interposes upper and lower dentries.
113 * Returns zero on success; non-zero otherwise
115 static int ecryptfs_interpose(struct dentry *lower_dentry,
116 struct dentry *dentry, struct super_block *sb)
118 struct inode *inode = ecryptfs_get_inode(d_inode(lower_dentry), sb);
121 return PTR_ERR(inode);
122 d_instantiate(dentry, inode);
127 static int ecryptfs_do_unlink(struct inode *dir, struct dentry *dentry,
130 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
131 struct dentry *lower_dir_dentry;
132 struct inode *lower_dir_inode;
135 lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
136 lower_dir_inode = d_inode(lower_dir_dentry);
137 inode_lock_nested(lower_dir_inode, I_MUTEX_PARENT);
138 dget(lower_dentry); // don't even try to make the lower negative
139 if (lower_dentry->d_parent != lower_dir_dentry)
141 else if (d_unhashed(lower_dentry))
144 rc = vfs_unlink(&init_user_ns, lower_dir_inode, lower_dentry,
147 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
150 fsstack_copy_attr_times(dir, lower_dir_inode);
151 set_nlink(inode, ecryptfs_inode_to_lower(inode)->i_nlink);
152 inode->i_ctime = dir->i_ctime;
155 inode_unlock(lower_dir_inode);
163 * @directory_inode: inode of the new file's dentry's parent in ecryptfs
164 * @ecryptfs_dentry: New file's dentry in ecryptfs
165 * @mode: The mode of the new file
167 * Creates the underlying file and the eCryptfs inode which will link to
168 * it. It will also update the eCryptfs directory inode to mimic the
169 * stat of the lower directory inode.
171 * Returns the new eCryptfs inode on success; an ERR_PTR on error condition
173 static struct inode *
174 ecryptfs_do_create(struct inode *directory_inode,
175 struct dentry *ecryptfs_dentry, umode_t mode)
178 struct dentry *lower_dentry;
179 struct dentry *lower_dir_dentry;
182 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
183 lower_dir_dentry = lock_parent(lower_dentry);
184 rc = vfs_create(&init_user_ns, d_inode(lower_dir_dentry), lower_dentry,
187 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
188 "rc = [%d]\n", __func__, rc);
192 inode = __ecryptfs_get_inode(d_inode(lower_dentry),
193 directory_inode->i_sb);
195 vfs_unlink(&init_user_ns, d_inode(lower_dir_dentry),
199 fsstack_copy_attr_times(directory_inode, d_inode(lower_dir_dentry));
200 fsstack_copy_inode_size(directory_inode, d_inode(lower_dir_dentry));
202 unlock_dir(lower_dir_dentry);
207 * ecryptfs_initialize_file
209 * Cause the file to be changed from a basic empty file to an ecryptfs
210 * file with a header and first data page.
212 * Returns zero on success
214 int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry,
215 struct inode *ecryptfs_inode)
217 struct ecryptfs_crypt_stat *crypt_stat =
218 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
221 if (S_ISDIR(ecryptfs_inode->i_mode)) {
222 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
223 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
226 ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
227 rc = ecryptfs_new_file_context(ecryptfs_inode);
229 ecryptfs_printk(KERN_ERR, "Error creating new file "
230 "context; rc = [%d]\n", rc);
233 rc = ecryptfs_get_lower_file(ecryptfs_dentry, ecryptfs_inode);
235 printk(KERN_ERR "%s: Error attempting to initialize "
236 "the lower file for the dentry with name "
237 "[%pd]; rc = [%d]\n", __func__,
238 ecryptfs_dentry, rc);
241 rc = ecryptfs_write_metadata(ecryptfs_dentry, ecryptfs_inode);
243 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
244 ecryptfs_put_lower_file(ecryptfs_inode);
251 * @dir: The inode of the directory in which to create the file.
252 * @dentry: The eCryptfs dentry
253 * @mode: The mode of the new file.
255 * Creates a new file.
257 * Returns zero on success; non-zero on error condition
260 ecryptfs_create(struct user_namespace *mnt_userns,
261 struct inode *directory_inode, struct dentry *ecryptfs_dentry,
262 umode_t mode, bool excl)
264 struct inode *ecryptfs_inode;
267 ecryptfs_inode = ecryptfs_do_create(directory_inode, ecryptfs_dentry,
269 if (IS_ERR(ecryptfs_inode)) {
270 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
271 "lower filesystem\n");
272 rc = PTR_ERR(ecryptfs_inode);
275 /* At this point, a file exists on "disk"; we need to make sure
276 * that this on disk file is prepared to be an ecryptfs file */
277 rc = ecryptfs_initialize_file(ecryptfs_dentry, ecryptfs_inode);
279 ecryptfs_do_unlink(directory_inode, ecryptfs_dentry,
281 iget_failed(ecryptfs_inode);
284 d_instantiate_new(ecryptfs_dentry, ecryptfs_inode);
289 static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode)
291 struct ecryptfs_crypt_stat *crypt_stat;
294 rc = ecryptfs_get_lower_file(dentry, inode);
296 printk(KERN_ERR "%s: Error attempting to initialize "
297 "the lower file for the dentry with name "
298 "[%pd]; rc = [%d]\n", __func__,
303 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
304 /* TODO: lock for crypt_stat comparison */
305 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
306 ecryptfs_set_default_sizes(crypt_stat);
308 rc = ecryptfs_read_and_validate_header_region(inode);
309 ecryptfs_put_lower_file(inode);
311 rc = ecryptfs_read_and_validate_xattr_region(dentry, inode);
313 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
316 /* Must return 0 to allow non-eCryptfs files to be looked up, too */
321 * ecryptfs_lookup_interpose - Dentry interposition for a lookup
323 static struct dentry *ecryptfs_lookup_interpose(struct dentry *dentry,
324 struct dentry *lower_dentry)
326 struct path *path = ecryptfs_dentry_to_lower_path(dentry->d_parent);
327 struct inode *inode, *lower_inode;
328 struct ecryptfs_dentry_info *dentry_info;
331 dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
334 return ERR_PTR(-ENOMEM);
337 fsstack_copy_attr_atime(d_inode(dentry->d_parent),
338 d_inode(path->dentry));
339 BUG_ON(!d_count(lower_dentry));
341 ecryptfs_set_dentry_private(dentry, dentry_info);
342 dentry_info->lower_path.mnt = mntget(path->mnt);
343 dentry_info->lower_path.dentry = lower_dentry;
346 * negative dentry can go positive under us here - its parent is not
347 * locked. That's OK and that could happen just as we return from
348 * ecryptfs_lookup() anyway. Just need to be careful and fetch
349 * ->d_inode only once - it's not stable here.
351 lower_inode = READ_ONCE(lower_dentry->d_inode);
354 /* We want to add because we couldn't find in lower */
358 inode = __ecryptfs_get_inode(lower_inode, dentry->d_sb);
360 printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
361 __func__, PTR_ERR(inode));
362 return ERR_CAST(inode);
364 if (S_ISREG(inode->i_mode)) {
365 rc = ecryptfs_i_size_read(dentry, inode);
367 make_bad_inode(inode);
372 if (inode->i_state & I_NEW)
373 unlock_new_inode(inode);
374 return d_splice_alias(inode, dentry);
379 * @ecryptfs_dir_inode: The eCryptfs directory inode
380 * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
381 * @flags: lookup flags
383 * Find a file on disk. If the file does not exist, then we'll add it to the
384 * dentry cache and continue on to read it from the disk.
386 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
387 struct dentry *ecryptfs_dentry,
390 char *encrypted_and_encoded_name = NULL;
391 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
392 struct dentry *lower_dir_dentry, *lower_dentry;
393 const char *name = ecryptfs_dentry->d_name.name;
394 size_t len = ecryptfs_dentry->d_name.len;
398 lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
400 mount_crypt_stat = &ecryptfs_superblock_to_private(
401 ecryptfs_dentry->d_sb)->mount_crypt_stat;
402 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
403 rc = ecryptfs_encrypt_and_encode_filename(
404 &encrypted_and_encoded_name, &len,
405 mount_crypt_stat, name, len);
407 printk(KERN_ERR "%s: Error attempting to encrypt and encode "
408 "filename; rc = [%d]\n", __func__, rc);
411 name = encrypted_and_encoded_name;
414 lower_dentry = lookup_one_len_unlocked(name, lower_dir_dentry, len);
415 if (IS_ERR(lower_dentry)) {
416 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
417 "[%ld] on lower_dentry = [%s]\n", __func__,
418 PTR_ERR(lower_dentry),
420 res = ERR_CAST(lower_dentry);
422 res = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry);
424 kfree(encrypted_and_encoded_name);
428 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
429 struct dentry *new_dentry)
431 struct dentry *lower_old_dentry;
432 struct dentry *lower_new_dentry;
433 struct dentry *lower_dir_dentry;
437 file_size_save = i_size_read(d_inode(old_dentry));
438 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
439 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
440 dget(lower_old_dentry);
441 dget(lower_new_dentry);
442 lower_dir_dentry = lock_parent(lower_new_dentry);
443 rc = vfs_link(lower_old_dentry, &init_user_ns,
444 d_inode(lower_dir_dentry), lower_new_dentry, NULL);
445 if (rc || d_really_is_negative(lower_new_dentry))
447 rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
450 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
451 fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
452 set_nlink(d_inode(old_dentry),
453 ecryptfs_inode_to_lower(d_inode(old_dentry))->i_nlink);
454 i_size_write(d_inode(new_dentry), file_size_save);
456 unlock_dir(lower_dir_dentry);
457 dput(lower_new_dentry);
458 dput(lower_old_dentry);
462 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
464 return ecryptfs_do_unlink(dir, dentry, d_inode(dentry));
467 static int ecryptfs_symlink(struct user_namespace *mnt_userns,
468 struct inode *dir, struct dentry *dentry,
472 struct dentry *lower_dentry;
473 struct dentry *lower_dir_dentry;
474 char *encoded_symname;
475 size_t encoded_symlen;
476 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
478 lower_dentry = ecryptfs_dentry_to_lower(dentry);
480 lower_dir_dentry = lock_parent(lower_dentry);
481 mount_crypt_stat = &ecryptfs_superblock_to_private(
482 dir->i_sb)->mount_crypt_stat;
483 rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
485 mount_crypt_stat, symname,
489 rc = vfs_symlink(&init_user_ns, d_inode(lower_dir_dentry), lower_dentry,
491 kfree(encoded_symname);
492 if (rc || d_really_is_negative(lower_dentry))
494 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
497 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
498 fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
500 unlock_dir(lower_dir_dentry);
502 if (d_really_is_negative(dentry))
507 static int ecryptfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
508 struct dentry *dentry, umode_t mode)
511 struct dentry *lower_dentry;
512 struct dentry *lower_dir_dentry;
514 lower_dentry = ecryptfs_dentry_to_lower(dentry);
515 lower_dir_dentry = lock_parent(lower_dentry);
516 rc = vfs_mkdir(&init_user_ns, d_inode(lower_dir_dentry), lower_dentry,
518 if (rc || d_really_is_negative(lower_dentry))
520 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
523 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
524 fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
525 set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
527 unlock_dir(lower_dir_dentry);
528 if (d_really_is_negative(dentry))
533 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
535 struct dentry *lower_dentry;
536 struct dentry *lower_dir_dentry;
537 struct inode *lower_dir_inode;
540 lower_dentry = ecryptfs_dentry_to_lower(dentry);
541 lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
542 lower_dir_inode = d_inode(lower_dir_dentry);
544 inode_lock_nested(lower_dir_inode, I_MUTEX_PARENT);
545 dget(lower_dentry); // don't even try to make the lower negative
546 if (lower_dentry->d_parent != lower_dir_dentry)
548 else if (d_unhashed(lower_dentry))
551 rc = vfs_rmdir(&init_user_ns, lower_dir_inode, lower_dentry);
553 clear_nlink(d_inode(dentry));
554 fsstack_copy_attr_times(dir, lower_dir_inode);
555 set_nlink(dir, lower_dir_inode->i_nlink);
558 inode_unlock(lower_dir_inode);
565 ecryptfs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
566 struct dentry *dentry, umode_t mode, dev_t dev)
569 struct dentry *lower_dentry;
570 struct dentry *lower_dir_dentry;
572 lower_dentry = ecryptfs_dentry_to_lower(dentry);
573 lower_dir_dentry = lock_parent(lower_dentry);
574 rc = vfs_mknod(&init_user_ns, d_inode(lower_dir_dentry), lower_dentry,
576 if (rc || d_really_is_negative(lower_dentry))
578 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
581 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
582 fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
584 unlock_dir(lower_dir_dentry);
585 if (d_really_is_negative(dentry))
591 ecryptfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
592 struct dentry *old_dentry, struct inode *new_dir,
593 struct dentry *new_dentry, unsigned int flags)
596 struct dentry *lower_old_dentry;
597 struct dentry *lower_new_dentry;
598 struct dentry *lower_old_dir_dentry;
599 struct dentry *lower_new_dir_dentry;
601 struct inode *target_inode;
602 struct renamedata rd = {};
607 lower_old_dir_dentry = ecryptfs_dentry_to_lower(old_dentry->d_parent);
608 lower_new_dir_dentry = ecryptfs_dentry_to_lower(new_dentry->d_parent);
610 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
611 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
613 target_inode = d_inode(new_dentry);
615 trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
616 dget(lower_new_dentry);
618 if (lower_old_dentry->d_parent != lower_old_dir_dentry)
620 if (lower_new_dentry->d_parent != lower_new_dir_dentry)
622 if (d_unhashed(lower_old_dentry) || d_unhashed(lower_new_dentry))
624 /* source should not be ancestor of target */
625 if (trap == lower_old_dentry)
627 /* target should not be ancestor of source */
628 if (trap == lower_new_dentry) {
633 rd.old_mnt_userns = &init_user_ns;
634 rd.old_dir = d_inode(lower_old_dir_dentry);
635 rd.old_dentry = lower_old_dentry;
636 rd.new_mnt_userns = &init_user_ns;
637 rd.new_dir = d_inode(lower_new_dir_dentry);
638 rd.new_dentry = lower_new_dentry;
639 rc = vfs_rename(&rd);
643 fsstack_copy_attr_all(target_inode,
644 ecryptfs_inode_to_lower(target_inode));
645 fsstack_copy_attr_all(new_dir, d_inode(lower_new_dir_dentry));
646 if (new_dir != old_dir)
647 fsstack_copy_attr_all(old_dir, d_inode(lower_old_dir_dentry));
649 dput(lower_new_dentry);
650 unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
654 static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
656 DEFINE_DELAYED_CALL(done);
657 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
662 link = vfs_get_link(lower_dentry, &done);
664 return ERR_CAST(link);
666 rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb,
668 do_delayed_call(&done);
675 static const char *ecryptfs_get_link(struct dentry *dentry,
677 struct delayed_call *done)
683 return ERR_PTR(-ECHILD);
685 buf = ecryptfs_readlink_lower(dentry, &len);
688 fsstack_copy_attr_atime(d_inode(dentry),
689 d_inode(ecryptfs_dentry_to_lower(dentry)));
691 set_delayed_call(done, kfree_link, buf);
696 * upper_size_to_lower_size
697 * @crypt_stat: Crypt_stat associated with file
698 * @upper_size: Size of the upper file
700 * Calculate the required size of the lower file based on the
701 * specified size of the upper file. This calculation is based on the
702 * number of headers in the underlying file and the extent size.
704 * Returns Calculated size of the lower file.
707 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
712 lower_size = ecryptfs_lower_header_size(crypt_stat);
713 if (upper_size != 0) {
716 num_extents = upper_size >> crypt_stat->extent_shift;
717 if (upper_size & ~crypt_stat->extent_mask)
719 lower_size += (num_extents * crypt_stat->extent_size);
726 * @dentry: The ecryptfs layer dentry
727 * @ia: Address of the ecryptfs inode's attributes
728 * @lower_ia: Address of the lower inode's attributes
730 * Function to handle truncations modifying the size of the file. Note
731 * that the file sizes are interpolated. When expanding, we are simply
732 * writing strings of 0's out. When truncating, we truncate the upper
733 * inode and update the lower_ia according to the page index
734 * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
735 * the caller must use lower_ia in a call to notify_change() to perform
736 * the truncation of the lower inode.
738 * Returns zero on success; non-zero otherwise
740 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
741 struct iattr *lower_ia)
744 struct inode *inode = d_inode(dentry);
745 struct ecryptfs_crypt_stat *crypt_stat;
746 loff_t i_size = i_size_read(inode);
747 loff_t lower_size_before_truncate;
748 loff_t lower_size_after_truncate;
750 if (unlikely((ia->ia_size == i_size))) {
751 lower_ia->ia_valid &= ~ATTR_SIZE;
754 rc = ecryptfs_get_lower_file(dentry, inode);
757 crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
758 /* Switch on growing or shrinking file */
759 if (ia->ia_size > i_size) {
760 char zero[] = { 0x00 };
762 lower_ia->ia_valid &= ~ATTR_SIZE;
763 /* Write a single 0 at the last position of the file;
764 * this triggers code that will fill in 0's throughout
765 * the intermediate portion of the previous end of the
766 * file and the new and of the file */
767 rc = ecryptfs_write(inode, zero,
768 (ia->ia_size - 1), 1);
769 } else { /* ia->ia_size < i_size_read(inode) */
770 /* We're chopping off all the pages down to the page
771 * in which ia->ia_size is located. Fill in the end of
772 * that page from (ia->ia_size & ~PAGE_MASK) to
773 * PAGE_SIZE with zeros. */
774 size_t num_zeros = (PAGE_SIZE
775 - (ia->ia_size & ~PAGE_MASK));
777 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
778 truncate_setsize(inode, ia->ia_size);
779 lower_ia->ia_size = ia->ia_size;
780 lower_ia->ia_valid |= ATTR_SIZE;
786 zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
791 rc = ecryptfs_write(inode, zeros_virt,
792 ia->ia_size, num_zeros);
795 printk(KERN_ERR "Error attempting to zero out "
796 "the remainder of the end page on "
797 "reducing truncate; rc = [%d]\n", rc);
801 truncate_setsize(inode, ia->ia_size);
802 rc = ecryptfs_write_inode_size_to_metadata(inode);
804 printk(KERN_ERR "Problem with "
805 "ecryptfs_write_inode_size_to_metadata; "
809 /* We are reducing the size of the ecryptfs file, and need to
810 * know if we need to reduce the size of the lower file. */
811 lower_size_before_truncate =
812 upper_size_to_lower_size(crypt_stat, i_size);
813 lower_size_after_truncate =
814 upper_size_to_lower_size(crypt_stat, ia->ia_size);
815 if (lower_size_after_truncate < lower_size_before_truncate) {
816 lower_ia->ia_size = lower_size_after_truncate;
817 lower_ia->ia_valid |= ATTR_SIZE;
819 lower_ia->ia_valid &= ~ATTR_SIZE;
822 ecryptfs_put_lower_file(inode);
826 static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset)
828 struct ecryptfs_crypt_stat *crypt_stat;
829 loff_t lower_oldsize, lower_newsize;
831 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
832 lower_oldsize = upper_size_to_lower_size(crypt_stat,
834 lower_newsize = upper_size_to_lower_size(crypt_stat, offset);
835 if (lower_newsize > lower_oldsize) {
837 * The eCryptfs inode and the new *lower* size are mixed here
838 * because we may not have the lower i_mutex held and/or it may
839 * not be appropriate to call inode_newsize_ok() with inodes
840 * from other filesystems.
842 return inode_newsize_ok(inode, lower_newsize);
850 * @dentry: The ecryptfs layer dentry
851 * @new_length: The length to expand the file to
853 * Simple function that handles the truncation of an eCryptfs inode and
854 * its corresponding lower inode.
856 * Returns zero on success; non-zero otherwise
858 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
860 struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
861 struct iattr lower_ia = { .ia_valid = 0 };
864 rc = ecryptfs_inode_newsize_ok(d_inode(dentry), new_length);
868 rc = truncate_upper(dentry, &ia, &lower_ia);
869 if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
870 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
872 inode_lock(d_inode(lower_dentry));
873 rc = notify_change(&init_user_ns, lower_dentry,
875 inode_unlock(d_inode(lower_dentry));
881 ecryptfs_permission(struct user_namespace *mnt_userns, struct inode *inode,
884 return inode_permission(&init_user_ns,
885 ecryptfs_inode_to_lower(inode), mask);
890 * @dentry: dentry handle to the inode to modify
891 * @ia: Structure with flags of what to change and values
893 * Updates the metadata of an inode. If the update is to the size
894 * i.e. truncation, then ecryptfs_truncate will handle the size modification
895 * of both the ecryptfs inode and the lower inode.
897 * All other metadata changes will be passed right to the lower filesystem,
898 * and we will just update our inode to look like the lower.
900 static int ecryptfs_setattr(struct user_namespace *mnt_userns,
901 struct dentry *dentry, struct iattr *ia)
904 struct dentry *lower_dentry;
905 struct iattr lower_ia;
907 struct inode *lower_inode;
908 struct ecryptfs_crypt_stat *crypt_stat;
910 crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
911 if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)) {
912 rc = ecryptfs_init_crypt_stat(crypt_stat);
916 inode = d_inode(dentry);
917 lower_inode = ecryptfs_inode_to_lower(inode);
918 lower_dentry = ecryptfs_dentry_to_lower(dentry);
919 mutex_lock(&crypt_stat->cs_mutex);
920 if (d_is_dir(dentry))
921 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
922 else if (d_is_reg(dentry)
923 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
924 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
925 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
927 mount_crypt_stat = &ecryptfs_superblock_to_private(
928 dentry->d_sb)->mount_crypt_stat;
929 rc = ecryptfs_get_lower_file(dentry, inode);
931 mutex_unlock(&crypt_stat->cs_mutex);
934 rc = ecryptfs_read_metadata(dentry);
935 ecryptfs_put_lower_file(inode);
937 if (!(mount_crypt_stat->flags
938 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
940 printk(KERN_WARNING "Either the lower file "
941 "is not in a valid eCryptfs format, "
942 "or the key could not be retrieved. "
943 "Plaintext passthrough mode is not "
944 "enabled; returning -EIO\n");
945 mutex_unlock(&crypt_stat->cs_mutex);
949 crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
950 | ECRYPTFS_ENCRYPTED);
953 mutex_unlock(&crypt_stat->cs_mutex);
955 rc = setattr_prepare(&init_user_ns, dentry, ia);
958 if (ia->ia_valid & ATTR_SIZE) {
959 rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size);
964 memcpy(&lower_ia, ia, sizeof(lower_ia));
965 if (ia->ia_valid & ATTR_FILE)
966 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
967 if (ia->ia_valid & ATTR_SIZE) {
968 rc = truncate_upper(dentry, ia, &lower_ia);
974 * mode change is for clearing setuid/setgid bits. Allow lower fs
975 * to interpret this in its own way.
977 if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
978 lower_ia.ia_valid &= ~ATTR_MODE;
980 inode_lock(d_inode(lower_dentry));
981 rc = notify_change(&init_user_ns, lower_dentry, &lower_ia, NULL);
982 inode_unlock(d_inode(lower_dentry));
984 fsstack_copy_attr_all(inode, lower_inode);
988 static int ecryptfs_getattr_link(struct user_namespace *mnt_userns,
989 const struct path *path, struct kstat *stat,
990 u32 request_mask, unsigned int flags)
992 struct dentry *dentry = path->dentry;
993 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
996 mount_crypt_stat = &ecryptfs_superblock_to_private(
997 dentry->d_sb)->mount_crypt_stat;
998 generic_fillattr(&init_user_ns, d_inode(dentry), stat);
999 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
1003 target = ecryptfs_readlink_lower(dentry, &targetsiz);
1004 if (!IS_ERR(target)) {
1006 stat->size = targetsiz;
1008 rc = PTR_ERR(target);
1014 static int ecryptfs_getattr(struct user_namespace *mnt_userns,
1015 const struct path *path, struct kstat *stat,
1016 u32 request_mask, unsigned int flags)
1018 struct dentry *dentry = path->dentry;
1019 struct kstat lower_stat;
1022 rc = vfs_getattr(ecryptfs_dentry_to_lower_path(dentry), &lower_stat,
1023 request_mask, flags);
1025 fsstack_copy_attr_all(d_inode(dentry),
1026 ecryptfs_inode_to_lower(d_inode(dentry)));
1027 generic_fillattr(&init_user_ns, d_inode(dentry), stat);
1028 stat->blocks = lower_stat.blocks;
1034 ecryptfs_setxattr(struct dentry *dentry, struct inode *inode,
1035 const char *name, const void *value,
1036 size_t size, int flags)
1039 struct dentry *lower_dentry;
1041 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1042 if (!(d_inode(lower_dentry)->i_opflags & IOP_XATTR)) {
1046 rc = vfs_setxattr(&init_user_ns, lower_dentry, name, value, size,
1049 fsstack_copy_attr_all(inode, d_inode(lower_dentry));
1055 ecryptfs_getxattr_lower(struct dentry *lower_dentry, struct inode *lower_inode,
1056 const char *name, void *value, size_t size)
1060 if (!(lower_inode->i_opflags & IOP_XATTR)) {
1064 inode_lock(lower_inode);
1065 rc = __vfs_getxattr(lower_dentry, lower_inode, name, value, size);
1066 inode_unlock(lower_inode);
1072 ecryptfs_getxattr(struct dentry *dentry, struct inode *inode,
1073 const char *name, void *value, size_t size)
1075 return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
1076 ecryptfs_inode_to_lower(inode),
1081 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1084 struct dentry *lower_dentry;
1086 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1087 if (!d_inode(lower_dentry)->i_op->listxattr) {
1091 inode_lock(d_inode(lower_dentry));
1092 rc = d_inode(lower_dentry)->i_op->listxattr(lower_dentry, list, size);
1093 inode_unlock(d_inode(lower_dentry));
1098 static int ecryptfs_removexattr(struct dentry *dentry, struct inode *inode,
1102 struct dentry *lower_dentry;
1103 struct inode *lower_inode;
1105 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1106 lower_inode = ecryptfs_inode_to_lower(inode);
1107 if (!(lower_inode->i_opflags & IOP_XATTR)) {
1111 inode_lock(lower_inode);
1112 rc = __vfs_removexattr(&init_user_ns, lower_dentry, name);
1113 inode_unlock(lower_inode);
1118 const struct inode_operations ecryptfs_symlink_iops = {
1119 .get_link = ecryptfs_get_link,
1120 .permission = ecryptfs_permission,
1121 .setattr = ecryptfs_setattr,
1122 .getattr = ecryptfs_getattr_link,
1123 .listxattr = ecryptfs_listxattr,
1126 const struct inode_operations ecryptfs_dir_iops = {
1127 .create = ecryptfs_create,
1128 .lookup = ecryptfs_lookup,
1129 .link = ecryptfs_link,
1130 .unlink = ecryptfs_unlink,
1131 .symlink = ecryptfs_symlink,
1132 .mkdir = ecryptfs_mkdir,
1133 .rmdir = ecryptfs_rmdir,
1134 .mknod = ecryptfs_mknod,
1135 .rename = ecryptfs_rename,
1136 .permission = ecryptfs_permission,
1137 .setattr = ecryptfs_setattr,
1138 .listxattr = ecryptfs_listxattr,
1141 const struct inode_operations ecryptfs_main_iops = {
1142 .permission = ecryptfs_permission,
1143 .setattr = ecryptfs_setattr,
1144 .getattr = ecryptfs_getattr,
1145 .listxattr = ecryptfs_listxattr,
1148 static int ecryptfs_xattr_get(const struct xattr_handler *handler,
1149 struct dentry *dentry, struct inode *inode,
1150 const char *name, void *buffer, size_t size)
1152 return ecryptfs_getxattr(dentry, inode, name, buffer, size);
1155 static int ecryptfs_xattr_set(const struct xattr_handler *handler,
1156 struct user_namespace *mnt_userns,
1157 struct dentry *dentry, struct inode *inode,
1158 const char *name, const void *value, size_t size,
1162 return ecryptfs_setxattr(dentry, inode, name, value, size, flags);
1164 BUG_ON(flags != XATTR_REPLACE);
1165 return ecryptfs_removexattr(dentry, inode, name);
1169 static const struct xattr_handler ecryptfs_xattr_handler = {
1170 .prefix = "", /* match anything */
1171 .get = ecryptfs_xattr_get,
1172 .set = ecryptfs_xattr_set,
1175 const struct xattr_handler *ecryptfs_xattr_handlers[] = {
1176 &ecryptfs_xattr_handler,