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1/**
2 * eCryptfs: Linux filesystem encryption layer
3 *
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>
9 *
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.
14 *
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.
19 *
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
23 * 02111-1307, USA.
24 */
25
26#include <linux/file.h>
27#include <linux/vmalloc.h>
28#include <linux/pagemap.h>
29#include <linux/dcache.h>
30#include <linux/namei.h>
31#include <linux/mount.h>
32#include <linux/fs_stack.h>
33#include <linux/slab.h>
34#include <linux/xattr.h>
35#include <asm/unaligned.h>
36#include "ecryptfs_kernel.h"
37
38static struct dentry *lock_parent(struct dentry *dentry)
39{
40 struct dentry *dir;
41
42 dir = dget_parent(dentry);
43 inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
44 return dir;
45}
46
47static void unlock_dir(struct dentry *dir)
48{
49 inode_unlock(d_inode(dir));
50 dput(dir);
51}
52
53static int ecryptfs_inode_test(struct inode *inode, void *lower_inode)
54{
55 return ecryptfs_inode_to_lower(inode) == lower_inode;
56}
57
58static int ecryptfs_inode_set(struct inode *inode, void *opaque)
59{
60 struct inode *lower_inode = opaque;
61
62 ecryptfs_set_inode_lower(inode, lower_inode);
63 fsstack_copy_attr_all(inode, lower_inode);
64 /* i_size will be overwritten for encrypted regular files */
65 fsstack_copy_inode_size(inode, lower_inode);
66 inode->i_ino = lower_inode->i_ino;
67 inode->i_version++;
68 inode->i_mapping->a_ops = &ecryptfs_aops;
69
70 if (S_ISLNK(inode->i_mode))
71 inode->i_op = &ecryptfs_symlink_iops;
72 else if (S_ISDIR(inode->i_mode))
73 inode->i_op = &ecryptfs_dir_iops;
74 else
75 inode->i_op = &ecryptfs_main_iops;
76
77 if (S_ISDIR(inode->i_mode))
78 inode->i_fop = &ecryptfs_dir_fops;
79 else if (special_file(inode->i_mode))
80 init_special_inode(inode, inode->i_mode, inode->i_rdev);
81 else
82 inode->i_fop = &ecryptfs_main_fops;
83
84 return 0;
85}
86
87static struct inode *__ecryptfs_get_inode(struct inode *lower_inode,
88 struct super_block *sb)
89{
90 struct inode *inode;
91
92 if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb))
93 return ERR_PTR(-EXDEV);
94 if (!igrab(lower_inode))
95 return ERR_PTR(-ESTALE);
96 inode = iget5_locked(sb, (unsigned long)lower_inode,
97 ecryptfs_inode_test, ecryptfs_inode_set,
98 lower_inode);
99 if (!inode) {
100 iput(lower_inode);
101 return ERR_PTR(-EACCES);
102 }
103 if (!(inode->i_state & I_NEW))
104 iput(lower_inode);
105
106 return inode;
107}
108
109struct inode *ecryptfs_get_inode(struct inode *lower_inode,
110 struct super_block *sb)
111{
112 struct inode *inode = __ecryptfs_get_inode(lower_inode, sb);
113
114 if (!IS_ERR(inode) && (inode->i_state & I_NEW))
115 unlock_new_inode(inode);
116
117 return inode;
118}
119
120/**
121 * ecryptfs_interpose
122 * @lower_dentry: Existing dentry in the lower filesystem
123 * @dentry: ecryptfs' dentry
124 * @sb: ecryptfs's super_block
125 *
126 * Interposes upper and lower dentries.
127 *
128 * Returns zero on success; non-zero otherwise
129 */
130static int ecryptfs_interpose(struct dentry *lower_dentry,
131 struct dentry *dentry, struct super_block *sb)
132{
133 struct inode *inode = ecryptfs_get_inode(d_inode(lower_dentry), sb);
134
135 if (IS_ERR(inode))
136 return PTR_ERR(inode);
137 d_instantiate(dentry, inode);
138
139 return 0;
140}
141
142static int ecryptfs_do_unlink(struct inode *dir, struct dentry *dentry,
143 struct inode *inode)
144{
145 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
146 struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
147 struct dentry *lower_dir_dentry;
148 int rc;
149
150 dget(lower_dentry);
151 lower_dir_dentry = lock_parent(lower_dentry);
152 rc = vfs_unlink(lower_dir_inode, lower_dentry, NULL);
153 if (rc) {
154 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
155 goto out_unlock;
156 }
157 fsstack_copy_attr_times(dir, lower_dir_inode);
158 set_nlink(inode, ecryptfs_inode_to_lower(inode)->i_nlink);
159 inode->i_ctime = dir->i_ctime;
160 d_drop(dentry);
161out_unlock:
162 unlock_dir(lower_dir_dentry);
163 dput(lower_dentry);
164 return rc;
165}
166
167/**
168 * ecryptfs_do_create
169 * @directory_inode: inode of the new file's dentry's parent in ecryptfs
170 * @ecryptfs_dentry: New file's dentry in ecryptfs
171 * @mode: The mode of the new file
172 *
173 * Creates the underlying file and the eCryptfs inode which will link to
174 * it. It will also update the eCryptfs directory inode to mimic the
175 * stat of the lower directory inode.
176 *
177 * Returns the new eCryptfs inode on success; an ERR_PTR on error condition
178 */
179static struct inode *
180ecryptfs_do_create(struct inode *directory_inode,
181 struct dentry *ecryptfs_dentry, umode_t mode)
182{
183 int rc;
184 struct dentry *lower_dentry;
185 struct dentry *lower_dir_dentry;
186 struct inode *inode;
187
188 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
189 lower_dir_dentry = lock_parent(lower_dentry);
190 rc = vfs_create(d_inode(lower_dir_dentry), lower_dentry, mode, true);
191 if (rc) {
192 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
193 "rc = [%d]\n", __func__, rc);
194 inode = ERR_PTR(rc);
195 goto out_lock;
196 }
197 inode = __ecryptfs_get_inode(d_inode(lower_dentry),
198 directory_inode->i_sb);
199 if (IS_ERR(inode)) {
200 vfs_unlink(d_inode(lower_dir_dentry), lower_dentry, NULL);
201 goto out_lock;
202 }
203 fsstack_copy_attr_times(directory_inode, d_inode(lower_dir_dentry));
204 fsstack_copy_inode_size(directory_inode, d_inode(lower_dir_dentry));
205out_lock:
206 unlock_dir(lower_dir_dentry);
207 return inode;
208}
209
210/**
211 * ecryptfs_initialize_file
212 *
213 * Cause the file to be changed from a basic empty file to an ecryptfs
214 * file with a header and first data page.
215 *
216 * Returns zero on success
217 */
218int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry,
219 struct inode *ecryptfs_inode)
220{
221 struct ecryptfs_crypt_stat *crypt_stat =
222 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
223 int rc = 0;
224
225 if (S_ISDIR(ecryptfs_inode->i_mode)) {
226 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
227 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
228 goto out;
229 }
230 ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
231 rc = ecryptfs_new_file_context(ecryptfs_inode);
232 if (rc) {
233 ecryptfs_printk(KERN_ERR, "Error creating new file "
234 "context; rc = [%d]\n", rc);
235 goto out;
236 }
237 rc = ecryptfs_get_lower_file(ecryptfs_dentry, ecryptfs_inode);
238 if (rc) {
239 printk(KERN_ERR "%s: Error attempting to initialize "
240 "the lower file for the dentry with name "
241 "[%pd]; rc = [%d]\n", __func__,
242 ecryptfs_dentry, rc);
243 goto out;
244 }
245 rc = ecryptfs_write_metadata(ecryptfs_dentry, ecryptfs_inode);
246 if (rc)
247 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
248 ecryptfs_put_lower_file(ecryptfs_inode);
249out:
250 return rc;
251}
252
253/**
254 * ecryptfs_create
255 * @dir: The inode of the directory in which to create the file.
256 * @dentry: The eCryptfs dentry
257 * @mode: The mode of the new file.
258 *
259 * Creates a new file.
260 *
261 * Returns zero on success; non-zero on error condition
262 */
263static int
264ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
265 umode_t mode, bool excl)
266{
267 struct inode *ecryptfs_inode;
268 int rc;
269
270 ecryptfs_inode = ecryptfs_do_create(directory_inode, ecryptfs_dentry,
271 mode);
272 if (IS_ERR(ecryptfs_inode)) {
273 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
274 "lower filesystem\n");
275 rc = PTR_ERR(ecryptfs_inode);
276 goto out;
277 }
278 /* At this point, a file exists on "disk"; we need to make sure
279 * that this on disk file is prepared to be an ecryptfs file */
280 rc = ecryptfs_initialize_file(ecryptfs_dentry, ecryptfs_inode);
281 if (rc) {
282 ecryptfs_do_unlink(directory_inode, ecryptfs_dentry,
283 ecryptfs_inode);
284 iget_failed(ecryptfs_inode);
285 goto out;
286 }
287 unlock_new_inode(ecryptfs_inode);
288 d_instantiate(ecryptfs_dentry, ecryptfs_inode);
289out:
290 return rc;
291}
292
293static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode)
294{
295 struct ecryptfs_crypt_stat *crypt_stat;
296 int rc;
297
298 rc = ecryptfs_get_lower_file(dentry, inode);
299 if (rc) {
300 printk(KERN_ERR "%s: Error attempting to initialize "
301 "the lower file for the dentry with name "
302 "[%pd]; rc = [%d]\n", __func__,
303 dentry, rc);
304 return rc;
305 }
306
307 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
308 /* TODO: lock for crypt_stat comparison */
309 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
310 ecryptfs_set_default_sizes(crypt_stat);
311
312 rc = ecryptfs_read_and_validate_header_region(inode);
313 ecryptfs_put_lower_file(inode);
314 if (rc) {
315 rc = ecryptfs_read_and_validate_xattr_region(dentry, inode);
316 if (!rc)
317 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
318 }
319
320 /* Must return 0 to allow non-eCryptfs files to be looked up, too */
321 return 0;
322}
323
324/**
325 * ecryptfs_lookup_interpose - Dentry interposition for a lookup
326 */
327static struct dentry *ecryptfs_lookup_interpose(struct dentry *dentry,
328 struct dentry *lower_dentry)
329{
330 struct inode *inode, *lower_inode = d_inode(lower_dentry);
331 struct ecryptfs_dentry_info *dentry_info;
332 struct vfsmount *lower_mnt;
333 int rc = 0;
334
335 dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
336 if (!dentry_info) {
337 printk(KERN_ERR "%s: Out of memory whilst attempting "
338 "to allocate ecryptfs_dentry_info struct\n",
339 __func__);
340 dput(lower_dentry);
341 return ERR_PTR(-ENOMEM);
342 }
343
344 lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
345 fsstack_copy_attr_atime(d_inode(dentry->d_parent),
346 d_inode(lower_dentry->d_parent));
347 BUG_ON(!d_count(lower_dentry));
348
349 ecryptfs_set_dentry_private(dentry, dentry_info);
350 dentry_info->lower_path.mnt = lower_mnt;
351 dentry_info->lower_path.dentry = lower_dentry;
352
353 if (d_really_is_negative(lower_dentry)) {
354 /* We want to add because we couldn't find in lower */
355 d_add(dentry, NULL);
356 return NULL;
357 }
358 inode = __ecryptfs_get_inode(lower_inode, dentry->d_sb);
359 if (IS_ERR(inode)) {
360 printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
361 __func__, PTR_ERR(inode));
362 return ERR_CAST(inode);
363 }
364 if (S_ISREG(inode->i_mode)) {
365 rc = ecryptfs_i_size_read(dentry, inode);
366 if (rc) {
367 make_bad_inode(inode);
368 return ERR_PTR(rc);
369 }
370 }
371
372 if (inode->i_state & I_NEW)
373 unlock_new_inode(inode);
374 return d_splice_alias(inode, dentry);
375}
376
377/**
378 * ecryptfs_lookup
379 * @ecryptfs_dir_inode: The eCryptfs directory inode
380 * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
381 * @flags: lookup flags
382 *
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.
385 */
386static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
387 struct dentry *ecryptfs_dentry,
388 unsigned int flags)
389{
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;
395 struct dentry *res;
396 int rc = 0;
397
398 lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
399
400 mount_crypt_stat = &ecryptfs_superblock_to_private(
401 ecryptfs_dentry->d_sb)->mount_crypt_stat;
402 if (mount_crypt_stat
403 && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) {
404 rc = ecryptfs_encrypt_and_encode_filename(
405 &encrypted_and_encoded_name, &len,
406 mount_crypt_stat, name, len);
407 if (rc) {
408 printk(KERN_ERR "%s: Error attempting to encrypt and encode "
409 "filename; rc = [%d]\n", __func__, rc);
410 return ERR_PTR(rc);
411 }
412 name = encrypted_and_encoded_name;
413 }
414
415 lower_dentry = lookup_one_len_unlocked(name, lower_dir_dentry, len);
416 if (IS_ERR(lower_dentry)) {
417 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
418 "[%ld] on lower_dentry = [%s]\n", __func__,
419 PTR_ERR(lower_dentry),
420 name);
421 res = ERR_CAST(lower_dentry);
422 } else {
423 res = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry);
424 }
425 kfree(encrypted_and_encoded_name);
426 return res;
427}
428
429static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
430 struct dentry *new_dentry)
431{
432 struct dentry *lower_old_dentry;
433 struct dentry *lower_new_dentry;
434 struct dentry *lower_dir_dentry;
435 u64 file_size_save;
436 int rc;
437
438 file_size_save = i_size_read(d_inode(old_dentry));
439 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
440 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
441 dget(lower_old_dentry);
442 dget(lower_new_dentry);
443 lower_dir_dentry = lock_parent(lower_new_dentry);
444 rc = vfs_link(lower_old_dentry, d_inode(lower_dir_dentry),
445 lower_new_dentry, NULL);
446 if (rc || d_really_is_negative(lower_new_dentry))
447 goto out_lock;
448 rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
449 if (rc)
450 goto out_lock;
451 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
452 fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
453 set_nlink(d_inode(old_dentry),
454 ecryptfs_inode_to_lower(d_inode(old_dentry))->i_nlink);
455 i_size_write(d_inode(new_dentry), file_size_save);
456out_lock:
457 unlock_dir(lower_dir_dentry);
458 dput(lower_new_dentry);
459 dput(lower_old_dentry);
460 return rc;
461}
462
463static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
464{
465 return ecryptfs_do_unlink(dir, dentry, d_inode(dentry));
466}
467
468static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
469 const char *symname)
470{
471 int rc;
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;
477
478 lower_dentry = ecryptfs_dentry_to_lower(dentry);
479 dget(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,
484 &encoded_symlen,
485 mount_crypt_stat, symname,
486 strlen(symname));
487 if (rc)
488 goto out_lock;
489 rc = vfs_symlink(d_inode(lower_dir_dentry), lower_dentry,
490 encoded_symname);
491 kfree(encoded_symname);
492 if (rc || d_really_is_negative(lower_dentry))
493 goto out_lock;
494 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
495 if (rc)
496 goto out_lock;
497 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
498 fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
499out_lock:
500 unlock_dir(lower_dir_dentry);
501 dput(lower_dentry);
502 if (d_really_is_negative(dentry))
503 d_drop(dentry);
504 return rc;
505}
506
507static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
508{
509 int rc;
510 struct dentry *lower_dentry;
511 struct dentry *lower_dir_dentry;
512
513 lower_dentry = ecryptfs_dentry_to_lower(dentry);
514 lower_dir_dentry = lock_parent(lower_dentry);
515 rc = vfs_mkdir(d_inode(lower_dir_dentry), lower_dentry, mode);
516 if (rc || d_really_is_negative(lower_dentry))
517 goto out;
518 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
519 if (rc)
520 goto out;
521 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
522 fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
523 set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
524out:
525 unlock_dir(lower_dir_dentry);
526 if (d_really_is_negative(dentry))
527 d_drop(dentry);
528 return rc;
529}
530
531static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
532{
533 struct dentry *lower_dentry;
534 struct dentry *lower_dir_dentry;
535 int rc;
536
537 lower_dentry = ecryptfs_dentry_to_lower(dentry);
538 dget(dentry);
539 lower_dir_dentry = lock_parent(lower_dentry);
540 dget(lower_dentry);
541 rc = vfs_rmdir(d_inode(lower_dir_dentry), lower_dentry);
542 dput(lower_dentry);
543 if (!rc && d_really_is_positive(dentry))
544 clear_nlink(d_inode(dentry));
545 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
546 set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
547 unlock_dir(lower_dir_dentry);
548 if (!rc)
549 d_drop(dentry);
550 dput(dentry);
551 return rc;
552}
553
554static int
555ecryptfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
556{
557 int rc;
558 struct dentry *lower_dentry;
559 struct dentry *lower_dir_dentry;
560
561 lower_dentry = ecryptfs_dentry_to_lower(dentry);
562 lower_dir_dentry = lock_parent(lower_dentry);
563 rc = vfs_mknod(d_inode(lower_dir_dentry), lower_dentry, mode, dev);
564 if (rc || d_really_is_negative(lower_dentry))
565 goto out;
566 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
567 if (rc)
568 goto out;
569 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
570 fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
571out:
572 unlock_dir(lower_dir_dentry);
573 if (d_really_is_negative(dentry))
574 d_drop(dentry);
575 return rc;
576}
577
578static int
579ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
580 struct inode *new_dir, struct dentry *new_dentry,
581 unsigned int flags)
582{
583 int rc;
584 struct dentry *lower_old_dentry;
585 struct dentry *lower_new_dentry;
586 struct dentry *lower_old_dir_dentry;
587 struct dentry *lower_new_dir_dentry;
588 struct dentry *trap = NULL;
589 struct inode *target_inode;
590
591 if (flags)
592 return -EINVAL;
593
594 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
595 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
596 dget(lower_old_dentry);
597 dget(lower_new_dentry);
598 lower_old_dir_dentry = dget_parent(lower_old_dentry);
599 lower_new_dir_dentry = dget_parent(lower_new_dentry);
600 target_inode = d_inode(new_dentry);
601 trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
602 /* source should not be ancestor of target */
603 if (trap == lower_old_dentry) {
604 rc = -EINVAL;
605 goto out_lock;
606 }
607 /* target should not be ancestor of source */
608 if (trap == lower_new_dentry) {
609 rc = -ENOTEMPTY;
610 goto out_lock;
611 }
612 rc = vfs_rename(d_inode(lower_old_dir_dentry), lower_old_dentry,
613 d_inode(lower_new_dir_dentry), lower_new_dentry,
614 NULL, 0);
615 if (rc)
616 goto out_lock;
617 if (target_inode)
618 fsstack_copy_attr_all(target_inode,
619 ecryptfs_inode_to_lower(target_inode));
620 fsstack_copy_attr_all(new_dir, d_inode(lower_new_dir_dentry));
621 if (new_dir != old_dir)
622 fsstack_copy_attr_all(old_dir, d_inode(lower_old_dir_dentry));
623out_lock:
624 unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
625 dput(lower_new_dir_dentry);
626 dput(lower_old_dir_dentry);
627 dput(lower_new_dentry);
628 dput(lower_old_dentry);
629 return rc;
630}
631
632static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
633{
634 DEFINE_DELAYED_CALL(done);
635 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
636 const char *link;
637 char *buf;
638 int rc;
639
640 link = vfs_get_link(lower_dentry, &done);
641 if (IS_ERR(link))
642 return ERR_CAST(link);
643
644 rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb,
645 link, strlen(link));
646 do_delayed_call(&done);
647 if (rc)
648 return ERR_PTR(rc);
649
650 return buf;
651}
652
653static const char *ecryptfs_get_link(struct dentry *dentry,
654 struct inode *inode,
655 struct delayed_call *done)
656{
657 size_t len;
658 char *buf;
659
660 if (!dentry)
661 return ERR_PTR(-ECHILD);
662
663 buf = ecryptfs_readlink_lower(dentry, &len);
664 if (IS_ERR(buf))
665 return buf;
666 fsstack_copy_attr_atime(d_inode(dentry),
667 d_inode(ecryptfs_dentry_to_lower(dentry)));
668 buf[len] = '\0';
669 set_delayed_call(done, kfree_link, buf);
670 return buf;
671}
672
673/**
674 * upper_size_to_lower_size
675 * @crypt_stat: Crypt_stat associated with file
676 * @upper_size: Size of the upper file
677 *
678 * Calculate the required size of the lower file based on the
679 * specified size of the upper file. This calculation is based on the
680 * number of headers in the underlying file and the extent size.
681 *
682 * Returns Calculated size of the lower file.
683 */
684static loff_t
685upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
686 loff_t upper_size)
687{
688 loff_t lower_size;
689
690 lower_size = ecryptfs_lower_header_size(crypt_stat);
691 if (upper_size != 0) {
692 loff_t num_extents;
693
694 num_extents = upper_size >> crypt_stat->extent_shift;
695 if (upper_size & ~crypt_stat->extent_mask)
696 num_extents++;
697 lower_size += (num_extents * crypt_stat->extent_size);
698 }
699 return lower_size;
700}
701
702/**
703 * truncate_upper
704 * @dentry: The ecryptfs layer dentry
705 * @ia: Address of the ecryptfs inode's attributes
706 * @lower_ia: Address of the lower inode's attributes
707 *
708 * Function to handle truncations modifying the size of the file. Note
709 * that the file sizes are interpolated. When expanding, we are simply
710 * writing strings of 0's out. When truncating, we truncate the upper
711 * inode and update the lower_ia according to the page index
712 * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
713 * the caller must use lower_ia in a call to notify_change() to perform
714 * the truncation of the lower inode.
715 *
716 * Returns zero on success; non-zero otherwise
717 */
718static int truncate_upper(struct dentry *dentry, struct iattr *ia,
719 struct iattr *lower_ia)
720{
721 int rc = 0;
722 struct inode *inode = d_inode(dentry);
723 struct ecryptfs_crypt_stat *crypt_stat;
724 loff_t i_size = i_size_read(inode);
725 loff_t lower_size_before_truncate;
726 loff_t lower_size_after_truncate;
727
728 if (unlikely((ia->ia_size == i_size))) {
729 lower_ia->ia_valid &= ~ATTR_SIZE;
730 return 0;
731 }
732 rc = ecryptfs_get_lower_file(dentry, inode);
733 if (rc)
734 return rc;
735 crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
736 /* Switch on growing or shrinking file */
737 if (ia->ia_size > i_size) {
738 char zero[] = { 0x00 };
739
740 lower_ia->ia_valid &= ~ATTR_SIZE;
741 /* Write a single 0 at the last position of the file;
742 * this triggers code that will fill in 0's throughout
743 * the intermediate portion of the previous end of the
744 * file and the new and of the file */
745 rc = ecryptfs_write(inode, zero,
746 (ia->ia_size - 1), 1);
747 } else { /* ia->ia_size < i_size_read(inode) */
748 /* We're chopping off all the pages down to the page
749 * in which ia->ia_size is located. Fill in the end of
750 * that page from (ia->ia_size & ~PAGE_MASK) to
751 * PAGE_SIZE with zeros. */
752 size_t num_zeros = (PAGE_SIZE
753 - (ia->ia_size & ~PAGE_MASK));
754
755 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
756 truncate_setsize(inode, ia->ia_size);
757 lower_ia->ia_size = ia->ia_size;
758 lower_ia->ia_valid |= ATTR_SIZE;
759 goto out;
760 }
761 if (num_zeros) {
762 char *zeros_virt;
763
764 zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
765 if (!zeros_virt) {
766 rc = -ENOMEM;
767 goto out;
768 }
769 rc = ecryptfs_write(inode, zeros_virt,
770 ia->ia_size, num_zeros);
771 kfree(zeros_virt);
772 if (rc) {
773 printk(KERN_ERR "Error attempting to zero out "
774 "the remainder of the end page on "
775 "reducing truncate; rc = [%d]\n", rc);
776 goto out;
777 }
778 }
779 truncate_setsize(inode, ia->ia_size);
780 rc = ecryptfs_write_inode_size_to_metadata(inode);
781 if (rc) {
782 printk(KERN_ERR "Problem with "
783 "ecryptfs_write_inode_size_to_metadata; "
784 "rc = [%d]\n", rc);
785 goto out;
786 }
787 /* We are reducing the size of the ecryptfs file, and need to
788 * know if we need to reduce the size of the lower file. */
789 lower_size_before_truncate =
790 upper_size_to_lower_size(crypt_stat, i_size);
791 lower_size_after_truncate =
792 upper_size_to_lower_size(crypt_stat, ia->ia_size);
793 if (lower_size_after_truncate < lower_size_before_truncate) {
794 lower_ia->ia_size = lower_size_after_truncate;
795 lower_ia->ia_valid |= ATTR_SIZE;
796 } else
797 lower_ia->ia_valid &= ~ATTR_SIZE;
798 }
799out:
800 ecryptfs_put_lower_file(inode);
801 return rc;
802}
803
804static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset)
805{
806 struct ecryptfs_crypt_stat *crypt_stat;
807 loff_t lower_oldsize, lower_newsize;
808
809 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
810 lower_oldsize = upper_size_to_lower_size(crypt_stat,
811 i_size_read(inode));
812 lower_newsize = upper_size_to_lower_size(crypt_stat, offset);
813 if (lower_newsize > lower_oldsize) {
814 /*
815 * The eCryptfs inode and the new *lower* size are mixed here
816 * because we may not have the lower i_mutex held and/or it may
817 * not be appropriate to call inode_newsize_ok() with inodes
818 * from other filesystems.
819 */
820 return inode_newsize_ok(inode, lower_newsize);
821 }
822
823 return 0;
824}
825
826/**
827 * ecryptfs_truncate
828 * @dentry: The ecryptfs layer dentry
829 * @new_length: The length to expand the file to
830 *
831 * Simple function that handles the truncation of an eCryptfs inode and
832 * its corresponding lower inode.
833 *
834 * Returns zero on success; non-zero otherwise
835 */
836int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
837{
838 struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
839 struct iattr lower_ia = { .ia_valid = 0 };
840 int rc;
841
842 rc = ecryptfs_inode_newsize_ok(d_inode(dentry), new_length);
843 if (rc)
844 return rc;
845
846 rc = truncate_upper(dentry, &ia, &lower_ia);
847 if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
848 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
849
850 inode_lock(d_inode(lower_dentry));
851 rc = notify_change(lower_dentry, &lower_ia, NULL);
852 inode_unlock(d_inode(lower_dentry));
853 }
854 return rc;
855}
856
857static int
858ecryptfs_permission(struct inode *inode, int mask)
859{
860 return inode_permission(ecryptfs_inode_to_lower(inode), mask);
861}
862
863/**
864 * ecryptfs_setattr
865 * @dentry: dentry handle to the inode to modify
866 * @ia: Structure with flags of what to change and values
867 *
868 * Updates the metadata of an inode. If the update is to the size
869 * i.e. truncation, then ecryptfs_truncate will handle the size modification
870 * of both the ecryptfs inode and the lower inode.
871 *
872 * All other metadata changes will be passed right to the lower filesystem,
873 * and we will just update our inode to look like the lower.
874 */
875static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
876{
877 int rc = 0;
878 struct dentry *lower_dentry;
879 struct iattr lower_ia;
880 struct inode *inode;
881 struct inode *lower_inode;
882 struct ecryptfs_crypt_stat *crypt_stat;
883
884 crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
885 if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)) {
886 rc = ecryptfs_init_crypt_stat(crypt_stat);
887 if (rc)
888 return rc;
889 }
890 inode = d_inode(dentry);
891 lower_inode = ecryptfs_inode_to_lower(inode);
892 lower_dentry = ecryptfs_dentry_to_lower(dentry);
893 mutex_lock(&crypt_stat->cs_mutex);
894 if (d_is_dir(dentry))
895 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
896 else if (d_is_reg(dentry)
897 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
898 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
899 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
900
901 mount_crypt_stat = &ecryptfs_superblock_to_private(
902 dentry->d_sb)->mount_crypt_stat;
903 rc = ecryptfs_get_lower_file(dentry, inode);
904 if (rc) {
905 mutex_unlock(&crypt_stat->cs_mutex);
906 goto out;
907 }
908 rc = ecryptfs_read_metadata(dentry);
909 ecryptfs_put_lower_file(inode);
910 if (rc) {
911 if (!(mount_crypt_stat->flags
912 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
913 rc = -EIO;
914 printk(KERN_WARNING "Either the lower file "
915 "is not in a valid eCryptfs format, "
916 "or the key could not be retrieved. "
917 "Plaintext passthrough mode is not "
918 "enabled; returning -EIO\n");
919 mutex_unlock(&crypt_stat->cs_mutex);
920 goto out;
921 }
922 rc = 0;
923 crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
924 | ECRYPTFS_ENCRYPTED);
925 }
926 }
927 mutex_unlock(&crypt_stat->cs_mutex);
928
929 rc = setattr_prepare(dentry, ia);
930 if (rc)
931 goto out;
932 if (ia->ia_valid & ATTR_SIZE) {
933 rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size);
934 if (rc)
935 goto out;
936 }
937
938 memcpy(&lower_ia, ia, sizeof(lower_ia));
939 if (ia->ia_valid & ATTR_FILE)
940 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
941 if (ia->ia_valid & ATTR_SIZE) {
942 rc = truncate_upper(dentry, ia, &lower_ia);
943 if (rc < 0)
944 goto out;
945 }
946
947 /*
948 * mode change is for clearing setuid/setgid bits. Allow lower fs
949 * to interpret this in its own way.
950 */
951 if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
952 lower_ia.ia_valid &= ~ATTR_MODE;
953
954 inode_lock(d_inode(lower_dentry));
955 rc = notify_change(lower_dentry, &lower_ia, NULL);
956 inode_unlock(d_inode(lower_dentry));
957out:
958 fsstack_copy_attr_all(inode, lower_inode);
959 return rc;
960}
961
962static int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
963 struct kstat *stat)
964{
965 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
966 int rc = 0;
967
968 mount_crypt_stat = &ecryptfs_superblock_to_private(
969 dentry->d_sb)->mount_crypt_stat;
970 generic_fillattr(d_inode(dentry), stat);
971 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
972 char *target;
973 size_t targetsiz;
974
975 target = ecryptfs_readlink_lower(dentry, &targetsiz);
976 if (!IS_ERR(target)) {
977 kfree(target);
978 stat->size = targetsiz;
979 } else {
980 rc = PTR_ERR(target);
981 }
982 }
983 return rc;
984}
985
986static int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
987 struct kstat *stat)
988{
989 struct kstat lower_stat;
990 int rc;
991
992 rc = vfs_getattr(ecryptfs_dentry_to_lower_path(dentry), &lower_stat);
993 if (!rc) {
994 fsstack_copy_attr_all(d_inode(dentry),
995 ecryptfs_inode_to_lower(d_inode(dentry)));
996 generic_fillattr(d_inode(dentry), stat);
997 stat->blocks = lower_stat.blocks;
998 }
999 return rc;
1000}
1001
1002int
1003ecryptfs_setxattr(struct dentry *dentry, struct inode *inode,
1004 const char *name, const void *value,
1005 size_t size, int flags)
1006{
1007 int rc;
1008 struct dentry *lower_dentry;
1009
1010 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1011 if (!(d_inode(lower_dentry)->i_opflags & IOP_XATTR)) {
1012 rc = -EOPNOTSUPP;
1013 goto out;
1014 }
1015 rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1016 if (!rc && inode)
1017 fsstack_copy_attr_all(inode, d_inode(lower_dentry));
1018out:
1019 return rc;
1020}
1021
1022ssize_t
1023ecryptfs_getxattr_lower(struct dentry *lower_dentry, struct inode *lower_inode,
1024 const char *name, void *value, size_t size)
1025{
1026 int rc;
1027
1028 if (!(lower_inode->i_opflags & IOP_XATTR)) {
1029 rc = -EOPNOTSUPP;
1030 goto out;
1031 }
1032 inode_lock(lower_inode);
1033 rc = __vfs_getxattr(lower_dentry, lower_inode, name, value, size);
1034 inode_unlock(lower_inode);
1035out:
1036 return rc;
1037}
1038
1039static ssize_t
1040ecryptfs_getxattr(struct dentry *dentry, struct inode *inode,
1041 const char *name, void *value, size_t size)
1042{
1043 return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
1044 ecryptfs_inode_to_lower(inode),
1045 name, value, size);
1046}
1047
1048static ssize_t
1049ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1050{
1051 int rc = 0;
1052 struct dentry *lower_dentry;
1053
1054 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1055 if (!d_inode(lower_dentry)->i_op->listxattr) {
1056 rc = -EOPNOTSUPP;
1057 goto out;
1058 }
1059 inode_lock(d_inode(lower_dentry));
1060 rc = d_inode(lower_dentry)->i_op->listxattr(lower_dentry, list, size);
1061 inode_unlock(d_inode(lower_dentry));
1062out:
1063 return rc;
1064}
1065
1066static int ecryptfs_removexattr(struct dentry *dentry, struct inode *inode,
1067 const char *name)
1068{
1069 int rc;
1070 struct dentry *lower_dentry;
1071 struct inode *lower_inode;
1072
1073 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1074 lower_inode = ecryptfs_inode_to_lower(inode);
1075 if (!(lower_inode->i_opflags & IOP_XATTR)) {
1076 rc = -EOPNOTSUPP;
1077 goto out;
1078 }
1079 inode_lock(lower_inode);
1080 rc = __vfs_removexattr(lower_dentry, name);
1081 inode_unlock(lower_inode);
1082out:
1083 return rc;
1084}
1085
1086const struct inode_operations ecryptfs_symlink_iops = {
1087 .get_link = ecryptfs_get_link,
1088 .permission = ecryptfs_permission,
1089 .setattr = ecryptfs_setattr,
1090 .getattr = ecryptfs_getattr_link,
1091 .listxattr = ecryptfs_listxattr,
1092};
1093
1094const struct inode_operations ecryptfs_dir_iops = {
1095 .create = ecryptfs_create,
1096 .lookup = ecryptfs_lookup,
1097 .link = ecryptfs_link,
1098 .unlink = ecryptfs_unlink,
1099 .symlink = ecryptfs_symlink,
1100 .mkdir = ecryptfs_mkdir,
1101 .rmdir = ecryptfs_rmdir,
1102 .mknod = ecryptfs_mknod,
1103 .rename = ecryptfs_rename,
1104 .permission = ecryptfs_permission,
1105 .setattr = ecryptfs_setattr,
1106 .listxattr = ecryptfs_listxattr,
1107};
1108
1109const struct inode_operations ecryptfs_main_iops = {
1110 .permission = ecryptfs_permission,
1111 .setattr = ecryptfs_setattr,
1112 .getattr = ecryptfs_getattr,
1113 .listxattr = ecryptfs_listxattr,
1114};
1115
1116static int ecryptfs_xattr_get(const struct xattr_handler *handler,
1117 struct dentry *dentry, struct inode *inode,
1118 const char *name, void *buffer, size_t size)
1119{
1120 return ecryptfs_getxattr(dentry, inode, name, buffer, size);
1121}
1122
1123static int ecryptfs_xattr_set(const struct xattr_handler *handler,
1124 struct dentry *dentry, struct inode *inode,
1125 const char *name, const void *value, size_t size,
1126 int flags)
1127{
1128 if (value)
1129 return ecryptfs_setxattr(dentry, inode, name, value, size, flags);
1130 else {
1131 BUG_ON(flags != XATTR_REPLACE);
1132 return ecryptfs_removexattr(dentry, inode, name);
1133 }
1134}
1135
1136const struct xattr_handler ecryptfs_xattr_handler = {
1137 .prefix = "", /* match anything */
1138 .get = ecryptfs_xattr_get,
1139 .set = ecryptfs_xattr_set,
1140};
1141
1142const struct xattr_handler *ecryptfs_xattr_handlers[] = {
1143 &ecryptfs_xattr_handler,
1144 NULL
1145};
1// SPDX-License-Identifier: GPL-2.0-or-later
2/**
3 * eCryptfs: Linux filesystem encryption layer
4 *
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>
10 */
11
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"
23
24static struct dentry *lock_parent(struct dentry *dentry)
25{
26 struct dentry *dir;
27
28 dir = dget_parent(dentry);
29 inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
30 return dir;
31}
32
33static void unlock_dir(struct dentry *dir)
34{
35 inode_unlock(d_inode(dir));
36 dput(dir);
37}
38
39static int ecryptfs_inode_test(struct inode *inode, void *lower_inode)
40{
41 return ecryptfs_inode_to_lower(inode) == lower_inode;
42}
43
44static int ecryptfs_inode_set(struct inode *inode, void *opaque)
45{
46 struct inode *lower_inode = opaque;
47
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;
54
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;
59 else
60 inode->i_op = &ecryptfs_main_iops;
61
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);
66 else
67 inode->i_fop = &ecryptfs_main_fops;
68
69 return 0;
70}
71
72static struct inode *__ecryptfs_get_inode(struct inode *lower_inode,
73 struct super_block *sb)
74{
75 struct inode *inode;
76
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,
83 lower_inode);
84 if (!inode) {
85 iput(lower_inode);
86 return ERR_PTR(-EACCES);
87 }
88 if (!(inode->i_state & I_NEW))
89 iput(lower_inode);
90
91 return inode;
92}
93
94struct inode *ecryptfs_get_inode(struct inode *lower_inode,
95 struct super_block *sb)
96{
97 struct inode *inode = __ecryptfs_get_inode(lower_inode, sb);
98
99 if (!IS_ERR(inode) && (inode->i_state & I_NEW))
100 unlock_new_inode(inode);
101
102 return inode;
103}
104
105/**
106 * ecryptfs_interpose
107 * @lower_dentry: Existing dentry in the lower filesystem
108 * @dentry: ecryptfs' dentry
109 * @sb: ecryptfs's super_block
110 *
111 * Interposes upper and lower dentries.
112 *
113 * Returns zero on success; non-zero otherwise
114 */
115static int ecryptfs_interpose(struct dentry *lower_dentry,
116 struct dentry *dentry, struct super_block *sb)
117{
118 struct inode *inode = ecryptfs_get_inode(d_inode(lower_dentry), sb);
119
120 if (IS_ERR(inode))
121 return PTR_ERR(inode);
122 d_instantiate(dentry, inode);
123
124 return 0;
125}
126
127static int ecryptfs_do_unlink(struct inode *dir, struct dentry *dentry,
128 struct inode *inode)
129{
130 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
131 struct dentry *lower_dir_dentry;
132 struct inode *lower_dir_inode;
133 int rc;
134
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)
140 rc = -EINVAL;
141 else if (d_unhashed(lower_dentry))
142 rc = -EINVAL;
143 else
144 rc = vfs_unlink(lower_dir_inode, lower_dentry, NULL);
145 if (rc) {
146 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
147 goto out_unlock;
148 }
149 fsstack_copy_attr_times(dir, lower_dir_inode);
150 set_nlink(inode, ecryptfs_inode_to_lower(inode)->i_nlink);
151 inode->i_ctime = dir->i_ctime;
152out_unlock:
153 dput(lower_dentry);
154 inode_unlock(lower_dir_inode);
155 if (!rc)
156 d_drop(dentry);
157 return rc;
158}
159
160/**
161 * ecryptfs_do_create
162 * @directory_inode: inode of the new file's dentry's parent in ecryptfs
163 * @ecryptfs_dentry: New file's dentry in ecryptfs
164 * @mode: The mode of the new file
165 *
166 * Creates the underlying file and the eCryptfs inode which will link to
167 * it. It will also update the eCryptfs directory inode to mimic the
168 * stat of the lower directory inode.
169 *
170 * Returns the new eCryptfs inode on success; an ERR_PTR on error condition
171 */
172static struct inode *
173ecryptfs_do_create(struct inode *directory_inode,
174 struct dentry *ecryptfs_dentry, umode_t mode)
175{
176 int rc;
177 struct dentry *lower_dentry;
178 struct dentry *lower_dir_dentry;
179 struct inode *inode;
180
181 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
182 lower_dir_dentry = lock_parent(lower_dentry);
183 rc = vfs_create(d_inode(lower_dir_dentry), lower_dentry, mode, true);
184 if (rc) {
185 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
186 "rc = [%d]\n", __func__, rc);
187 inode = ERR_PTR(rc);
188 goto out_lock;
189 }
190 inode = __ecryptfs_get_inode(d_inode(lower_dentry),
191 directory_inode->i_sb);
192 if (IS_ERR(inode)) {
193 vfs_unlink(d_inode(lower_dir_dentry), lower_dentry, NULL);
194 goto out_lock;
195 }
196 fsstack_copy_attr_times(directory_inode, d_inode(lower_dir_dentry));
197 fsstack_copy_inode_size(directory_inode, d_inode(lower_dir_dentry));
198out_lock:
199 unlock_dir(lower_dir_dentry);
200 return inode;
201}
202
203/**
204 * ecryptfs_initialize_file
205 *
206 * Cause the file to be changed from a basic empty file to an ecryptfs
207 * file with a header and first data page.
208 *
209 * Returns zero on success
210 */
211int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry,
212 struct inode *ecryptfs_inode)
213{
214 struct ecryptfs_crypt_stat *crypt_stat =
215 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
216 int rc = 0;
217
218 if (S_ISDIR(ecryptfs_inode->i_mode)) {
219 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
220 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
221 goto out;
222 }
223 ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
224 rc = ecryptfs_new_file_context(ecryptfs_inode);
225 if (rc) {
226 ecryptfs_printk(KERN_ERR, "Error creating new file "
227 "context; rc = [%d]\n", rc);
228 goto out;
229 }
230 rc = ecryptfs_get_lower_file(ecryptfs_dentry, ecryptfs_inode);
231 if (rc) {
232 printk(KERN_ERR "%s: Error attempting to initialize "
233 "the lower file for the dentry with name "
234 "[%pd]; rc = [%d]\n", __func__,
235 ecryptfs_dentry, rc);
236 goto out;
237 }
238 rc = ecryptfs_write_metadata(ecryptfs_dentry, ecryptfs_inode);
239 if (rc)
240 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
241 ecryptfs_put_lower_file(ecryptfs_inode);
242out:
243 return rc;
244}
245
246/**
247 * ecryptfs_create
248 * @dir: The inode of the directory in which to create the file.
249 * @dentry: The eCryptfs dentry
250 * @mode: The mode of the new file.
251 *
252 * Creates a new file.
253 *
254 * Returns zero on success; non-zero on error condition
255 */
256static int
257ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
258 umode_t mode, bool excl)
259{
260 struct inode *ecryptfs_inode;
261 int rc;
262
263 ecryptfs_inode = ecryptfs_do_create(directory_inode, ecryptfs_dentry,
264 mode);
265 if (IS_ERR(ecryptfs_inode)) {
266 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
267 "lower filesystem\n");
268 rc = PTR_ERR(ecryptfs_inode);
269 goto out;
270 }
271 /* At this point, a file exists on "disk"; we need to make sure
272 * that this on disk file is prepared to be an ecryptfs file */
273 rc = ecryptfs_initialize_file(ecryptfs_dentry, ecryptfs_inode);
274 if (rc) {
275 ecryptfs_do_unlink(directory_inode, ecryptfs_dentry,
276 ecryptfs_inode);
277 iget_failed(ecryptfs_inode);
278 goto out;
279 }
280 d_instantiate_new(ecryptfs_dentry, ecryptfs_inode);
281out:
282 return rc;
283}
284
285static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode)
286{
287 struct ecryptfs_crypt_stat *crypt_stat;
288 int rc;
289
290 rc = ecryptfs_get_lower_file(dentry, inode);
291 if (rc) {
292 printk(KERN_ERR "%s: Error attempting to initialize "
293 "the lower file for the dentry with name "
294 "[%pd]; rc = [%d]\n", __func__,
295 dentry, rc);
296 return rc;
297 }
298
299 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
300 /* TODO: lock for crypt_stat comparison */
301 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
302 ecryptfs_set_default_sizes(crypt_stat);
303
304 rc = ecryptfs_read_and_validate_header_region(inode);
305 ecryptfs_put_lower_file(inode);
306 if (rc) {
307 rc = ecryptfs_read_and_validate_xattr_region(dentry, inode);
308 if (!rc)
309 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
310 }
311
312 /* Must return 0 to allow non-eCryptfs files to be looked up, too */
313 return 0;
314}
315
316/**
317 * ecryptfs_lookup_interpose - Dentry interposition for a lookup
318 */
319static struct dentry *ecryptfs_lookup_interpose(struct dentry *dentry,
320 struct dentry *lower_dentry)
321{
322 struct path *path = ecryptfs_dentry_to_lower_path(dentry->d_parent);
323 struct inode *inode, *lower_inode;
324 struct ecryptfs_dentry_info *dentry_info;
325 int rc = 0;
326
327 dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
328 if (!dentry_info) {
329 dput(lower_dentry);
330 return ERR_PTR(-ENOMEM);
331 }
332
333 fsstack_copy_attr_atime(d_inode(dentry->d_parent),
334 d_inode(path->dentry));
335 BUG_ON(!d_count(lower_dentry));
336
337 ecryptfs_set_dentry_private(dentry, dentry_info);
338 dentry_info->lower_path.mnt = mntget(path->mnt);
339 dentry_info->lower_path.dentry = lower_dentry;
340
341 /*
342 * negative dentry can go positive under us here - its parent is not
343 * locked. That's OK and that could happen just as we return from
344 * ecryptfs_lookup() anyway. Just need to be careful and fetch
345 * ->d_inode only once - it's not stable here.
346 */
347 lower_inode = READ_ONCE(lower_dentry->d_inode);
348
349 if (!lower_inode) {
350 /* We want to add because we couldn't find in lower */
351 d_add(dentry, NULL);
352 return NULL;
353 }
354 inode = __ecryptfs_get_inode(lower_inode, dentry->d_sb);
355 if (IS_ERR(inode)) {
356 printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
357 __func__, PTR_ERR(inode));
358 return ERR_CAST(inode);
359 }
360 if (S_ISREG(inode->i_mode)) {
361 rc = ecryptfs_i_size_read(dentry, inode);
362 if (rc) {
363 make_bad_inode(inode);
364 return ERR_PTR(rc);
365 }
366 }
367
368 if (inode->i_state & I_NEW)
369 unlock_new_inode(inode);
370 return d_splice_alias(inode, dentry);
371}
372
373/**
374 * ecryptfs_lookup
375 * @ecryptfs_dir_inode: The eCryptfs directory inode
376 * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
377 * @flags: lookup flags
378 *
379 * Find a file on disk. If the file does not exist, then we'll add it to the
380 * dentry cache and continue on to read it from the disk.
381 */
382static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
383 struct dentry *ecryptfs_dentry,
384 unsigned int flags)
385{
386 char *encrypted_and_encoded_name = NULL;
387 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
388 struct dentry *lower_dir_dentry, *lower_dentry;
389 const char *name = ecryptfs_dentry->d_name.name;
390 size_t len = ecryptfs_dentry->d_name.len;
391 struct dentry *res;
392 int rc = 0;
393
394 lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
395
396 mount_crypt_stat = &ecryptfs_superblock_to_private(
397 ecryptfs_dentry->d_sb)->mount_crypt_stat;
398 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
399 rc = ecryptfs_encrypt_and_encode_filename(
400 &encrypted_and_encoded_name, &len,
401 mount_crypt_stat, name, len);
402 if (rc) {
403 printk(KERN_ERR "%s: Error attempting to encrypt and encode "
404 "filename; rc = [%d]\n", __func__, rc);
405 return ERR_PTR(rc);
406 }
407 name = encrypted_and_encoded_name;
408 }
409
410 lower_dentry = lookup_one_len_unlocked(name, lower_dir_dentry, len);
411 if (IS_ERR(lower_dentry)) {
412 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
413 "[%ld] on lower_dentry = [%s]\n", __func__,
414 PTR_ERR(lower_dentry),
415 name);
416 res = ERR_CAST(lower_dentry);
417 } else {
418 res = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry);
419 }
420 kfree(encrypted_and_encoded_name);
421 return res;
422}
423
424static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
425 struct dentry *new_dentry)
426{
427 struct dentry *lower_old_dentry;
428 struct dentry *lower_new_dentry;
429 struct dentry *lower_dir_dentry;
430 u64 file_size_save;
431 int rc;
432
433 file_size_save = i_size_read(d_inode(old_dentry));
434 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
435 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
436 dget(lower_old_dentry);
437 dget(lower_new_dentry);
438 lower_dir_dentry = lock_parent(lower_new_dentry);
439 rc = vfs_link(lower_old_dentry, d_inode(lower_dir_dentry),
440 lower_new_dentry, NULL);
441 if (rc || d_really_is_negative(lower_new_dentry))
442 goto out_lock;
443 rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
444 if (rc)
445 goto out_lock;
446 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
447 fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
448 set_nlink(d_inode(old_dentry),
449 ecryptfs_inode_to_lower(d_inode(old_dentry))->i_nlink);
450 i_size_write(d_inode(new_dentry), file_size_save);
451out_lock:
452 unlock_dir(lower_dir_dentry);
453 dput(lower_new_dentry);
454 dput(lower_old_dentry);
455 return rc;
456}
457
458static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
459{
460 return ecryptfs_do_unlink(dir, dentry, d_inode(dentry));
461}
462
463static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
464 const char *symname)
465{
466 int rc;
467 struct dentry *lower_dentry;
468 struct dentry *lower_dir_dentry;
469 char *encoded_symname;
470 size_t encoded_symlen;
471 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
472
473 lower_dentry = ecryptfs_dentry_to_lower(dentry);
474 dget(lower_dentry);
475 lower_dir_dentry = lock_parent(lower_dentry);
476 mount_crypt_stat = &ecryptfs_superblock_to_private(
477 dir->i_sb)->mount_crypt_stat;
478 rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
479 &encoded_symlen,
480 mount_crypt_stat, symname,
481 strlen(symname));
482 if (rc)
483 goto out_lock;
484 rc = vfs_symlink(d_inode(lower_dir_dentry), lower_dentry,
485 encoded_symname);
486 kfree(encoded_symname);
487 if (rc || d_really_is_negative(lower_dentry))
488 goto out_lock;
489 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
490 if (rc)
491 goto out_lock;
492 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
493 fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
494out_lock:
495 unlock_dir(lower_dir_dentry);
496 dput(lower_dentry);
497 if (d_really_is_negative(dentry))
498 d_drop(dentry);
499 return rc;
500}
501
502static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
503{
504 int rc;
505 struct dentry *lower_dentry;
506 struct dentry *lower_dir_dentry;
507
508 lower_dentry = ecryptfs_dentry_to_lower(dentry);
509 lower_dir_dentry = lock_parent(lower_dentry);
510 rc = vfs_mkdir(d_inode(lower_dir_dentry), lower_dentry, mode);
511 if (rc || d_really_is_negative(lower_dentry))
512 goto out;
513 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
514 if (rc)
515 goto out;
516 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
517 fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
518 set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
519out:
520 unlock_dir(lower_dir_dentry);
521 if (d_really_is_negative(dentry))
522 d_drop(dentry);
523 return rc;
524}
525
526static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
527{
528 struct dentry *lower_dentry;
529 struct dentry *lower_dir_dentry;
530 struct inode *lower_dir_inode;
531 int rc;
532
533 lower_dentry = ecryptfs_dentry_to_lower(dentry);
534 lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
535 lower_dir_inode = d_inode(lower_dir_dentry);
536
537 inode_lock_nested(lower_dir_inode, I_MUTEX_PARENT);
538 dget(lower_dentry); // don't even try to make the lower negative
539 if (lower_dentry->d_parent != lower_dir_dentry)
540 rc = -EINVAL;
541 else if (d_unhashed(lower_dentry))
542 rc = -EINVAL;
543 else
544 rc = vfs_rmdir(lower_dir_inode, lower_dentry);
545 if (!rc) {
546 clear_nlink(d_inode(dentry));
547 fsstack_copy_attr_times(dir, lower_dir_inode);
548 set_nlink(dir, lower_dir_inode->i_nlink);
549 }
550 dput(lower_dentry);
551 inode_unlock(lower_dir_inode);
552 if (!rc)
553 d_drop(dentry);
554 return rc;
555}
556
557static int
558ecryptfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
559{
560 int rc;
561 struct dentry *lower_dentry;
562 struct dentry *lower_dir_dentry;
563
564 lower_dentry = ecryptfs_dentry_to_lower(dentry);
565 lower_dir_dentry = lock_parent(lower_dentry);
566 rc = vfs_mknod(d_inode(lower_dir_dentry), lower_dentry, mode, dev);
567 if (rc || d_really_is_negative(lower_dentry))
568 goto out;
569 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
570 if (rc)
571 goto out;
572 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
573 fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
574out:
575 unlock_dir(lower_dir_dentry);
576 if (d_really_is_negative(dentry))
577 d_drop(dentry);
578 return rc;
579}
580
581static int
582ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
583 struct inode *new_dir, struct dentry *new_dentry,
584 unsigned int flags)
585{
586 int rc;
587 struct dentry *lower_old_dentry;
588 struct dentry *lower_new_dentry;
589 struct dentry *lower_old_dir_dentry;
590 struct dentry *lower_new_dir_dentry;
591 struct dentry *trap;
592 struct inode *target_inode;
593
594 if (flags)
595 return -EINVAL;
596
597 lower_old_dir_dentry = ecryptfs_dentry_to_lower(old_dentry->d_parent);
598 lower_new_dir_dentry = ecryptfs_dentry_to_lower(new_dentry->d_parent);
599
600 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
601 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
602
603 target_inode = d_inode(new_dentry);
604
605 trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
606 dget(lower_new_dentry);
607 rc = -EINVAL;
608 if (lower_old_dentry->d_parent != lower_old_dir_dentry)
609 goto out_lock;
610 if (lower_new_dentry->d_parent != lower_new_dir_dentry)
611 goto out_lock;
612 if (d_unhashed(lower_old_dentry) || d_unhashed(lower_new_dentry))
613 goto out_lock;
614 /* source should not be ancestor of target */
615 if (trap == lower_old_dentry)
616 goto out_lock;
617 /* target should not be ancestor of source */
618 if (trap == lower_new_dentry) {
619 rc = -ENOTEMPTY;
620 goto out_lock;
621 }
622 rc = vfs_rename(d_inode(lower_old_dir_dentry), lower_old_dentry,
623 d_inode(lower_new_dir_dentry), lower_new_dentry,
624 NULL, 0);
625 if (rc)
626 goto out_lock;
627 if (target_inode)
628 fsstack_copy_attr_all(target_inode,
629 ecryptfs_inode_to_lower(target_inode));
630 fsstack_copy_attr_all(new_dir, d_inode(lower_new_dir_dentry));
631 if (new_dir != old_dir)
632 fsstack_copy_attr_all(old_dir, d_inode(lower_old_dir_dentry));
633out_lock:
634 dput(lower_new_dentry);
635 unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
636 return rc;
637}
638
639static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
640{
641 DEFINE_DELAYED_CALL(done);
642 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
643 const char *link;
644 char *buf;
645 int rc;
646
647 link = vfs_get_link(lower_dentry, &done);
648 if (IS_ERR(link))
649 return ERR_CAST(link);
650
651 rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb,
652 link, strlen(link));
653 do_delayed_call(&done);
654 if (rc)
655 return ERR_PTR(rc);
656
657 return buf;
658}
659
660static const char *ecryptfs_get_link(struct dentry *dentry,
661 struct inode *inode,
662 struct delayed_call *done)
663{
664 size_t len;
665 char *buf;
666
667 if (!dentry)
668 return ERR_PTR(-ECHILD);
669
670 buf = ecryptfs_readlink_lower(dentry, &len);
671 if (IS_ERR(buf))
672 return buf;
673 fsstack_copy_attr_atime(d_inode(dentry),
674 d_inode(ecryptfs_dentry_to_lower(dentry)));
675 buf[len] = '\0';
676 set_delayed_call(done, kfree_link, buf);
677 return buf;
678}
679
680/**
681 * upper_size_to_lower_size
682 * @crypt_stat: Crypt_stat associated with file
683 * @upper_size: Size of the upper file
684 *
685 * Calculate the required size of the lower file based on the
686 * specified size of the upper file. This calculation is based on the
687 * number of headers in the underlying file and the extent size.
688 *
689 * Returns Calculated size of the lower file.
690 */
691static loff_t
692upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
693 loff_t upper_size)
694{
695 loff_t lower_size;
696
697 lower_size = ecryptfs_lower_header_size(crypt_stat);
698 if (upper_size != 0) {
699 loff_t num_extents;
700
701 num_extents = upper_size >> crypt_stat->extent_shift;
702 if (upper_size & ~crypt_stat->extent_mask)
703 num_extents++;
704 lower_size += (num_extents * crypt_stat->extent_size);
705 }
706 return lower_size;
707}
708
709/**
710 * truncate_upper
711 * @dentry: The ecryptfs layer dentry
712 * @ia: Address of the ecryptfs inode's attributes
713 * @lower_ia: Address of the lower inode's attributes
714 *
715 * Function to handle truncations modifying the size of the file. Note
716 * that the file sizes are interpolated. When expanding, we are simply
717 * writing strings of 0's out. When truncating, we truncate the upper
718 * inode and update the lower_ia according to the page index
719 * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
720 * the caller must use lower_ia in a call to notify_change() to perform
721 * the truncation of the lower inode.
722 *
723 * Returns zero on success; non-zero otherwise
724 */
725static int truncate_upper(struct dentry *dentry, struct iattr *ia,
726 struct iattr *lower_ia)
727{
728 int rc = 0;
729 struct inode *inode = d_inode(dentry);
730 struct ecryptfs_crypt_stat *crypt_stat;
731 loff_t i_size = i_size_read(inode);
732 loff_t lower_size_before_truncate;
733 loff_t lower_size_after_truncate;
734
735 if (unlikely((ia->ia_size == i_size))) {
736 lower_ia->ia_valid &= ~ATTR_SIZE;
737 return 0;
738 }
739 rc = ecryptfs_get_lower_file(dentry, inode);
740 if (rc)
741 return rc;
742 crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
743 /* Switch on growing or shrinking file */
744 if (ia->ia_size > i_size) {
745 char zero[] = { 0x00 };
746
747 lower_ia->ia_valid &= ~ATTR_SIZE;
748 /* Write a single 0 at the last position of the file;
749 * this triggers code that will fill in 0's throughout
750 * the intermediate portion of the previous end of the
751 * file and the new and of the file */
752 rc = ecryptfs_write(inode, zero,
753 (ia->ia_size - 1), 1);
754 } else { /* ia->ia_size < i_size_read(inode) */
755 /* We're chopping off all the pages down to the page
756 * in which ia->ia_size is located. Fill in the end of
757 * that page from (ia->ia_size & ~PAGE_MASK) to
758 * PAGE_SIZE with zeros. */
759 size_t num_zeros = (PAGE_SIZE
760 - (ia->ia_size & ~PAGE_MASK));
761
762 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
763 truncate_setsize(inode, ia->ia_size);
764 lower_ia->ia_size = ia->ia_size;
765 lower_ia->ia_valid |= ATTR_SIZE;
766 goto out;
767 }
768 if (num_zeros) {
769 char *zeros_virt;
770
771 zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
772 if (!zeros_virt) {
773 rc = -ENOMEM;
774 goto out;
775 }
776 rc = ecryptfs_write(inode, zeros_virt,
777 ia->ia_size, num_zeros);
778 kfree(zeros_virt);
779 if (rc) {
780 printk(KERN_ERR "Error attempting to zero out "
781 "the remainder of the end page on "
782 "reducing truncate; rc = [%d]\n", rc);
783 goto out;
784 }
785 }
786 truncate_setsize(inode, ia->ia_size);
787 rc = ecryptfs_write_inode_size_to_metadata(inode);
788 if (rc) {
789 printk(KERN_ERR "Problem with "
790 "ecryptfs_write_inode_size_to_metadata; "
791 "rc = [%d]\n", rc);
792 goto out;
793 }
794 /* We are reducing the size of the ecryptfs file, and need to
795 * know if we need to reduce the size of the lower file. */
796 lower_size_before_truncate =
797 upper_size_to_lower_size(crypt_stat, i_size);
798 lower_size_after_truncate =
799 upper_size_to_lower_size(crypt_stat, ia->ia_size);
800 if (lower_size_after_truncate < lower_size_before_truncate) {
801 lower_ia->ia_size = lower_size_after_truncate;
802 lower_ia->ia_valid |= ATTR_SIZE;
803 } else
804 lower_ia->ia_valid &= ~ATTR_SIZE;
805 }
806out:
807 ecryptfs_put_lower_file(inode);
808 return rc;
809}
810
811static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset)
812{
813 struct ecryptfs_crypt_stat *crypt_stat;
814 loff_t lower_oldsize, lower_newsize;
815
816 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
817 lower_oldsize = upper_size_to_lower_size(crypt_stat,
818 i_size_read(inode));
819 lower_newsize = upper_size_to_lower_size(crypt_stat, offset);
820 if (lower_newsize > lower_oldsize) {
821 /*
822 * The eCryptfs inode and the new *lower* size are mixed here
823 * because we may not have the lower i_mutex held and/or it may
824 * not be appropriate to call inode_newsize_ok() with inodes
825 * from other filesystems.
826 */
827 return inode_newsize_ok(inode, lower_newsize);
828 }
829
830 return 0;
831}
832
833/**
834 * ecryptfs_truncate
835 * @dentry: The ecryptfs layer dentry
836 * @new_length: The length to expand the file to
837 *
838 * Simple function that handles the truncation of an eCryptfs inode and
839 * its corresponding lower inode.
840 *
841 * Returns zero on success; non-zero otherwise
842 */
843int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
844{
845 struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
846 struct iattr lower_ia = { .ia_valid = 0 };
847 int rc;
848
849 rc = ecryptfs_inode_newsize_ok(d_inode(dentry), new_length);
850 if (rc)
851 return rc;
852
853 rc = truncate_upper(dentry, &ia, &lower_ia);
854 if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
855 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
856
857 inode_lock(d_inode(lower_dentry));
858 rc = notify_change(lower_dentry, &lower_ia, NULL);
859 inode_unlock(d_inode(lower_dentry));
860 }
861 return rc;
862}
863
864static int
865ecryptfs_permission(struct inode *inode, int mask)
866{
867 return inode_permission(ecryptfs_inode_to_lower(inode), mask);
868}
869
870/**
871 * ecryptfs_setattr
872 * @dentry: dentry handle to the inode to modify
873 * @ia: Structure with flags of what to change and values
874 *
875 * Updates the metadata of an inode. If the update is to the size
876 * i.e. truncation, then ecryptfs_truncate will handle the size modification
877 * of both the ecryptfs inode and the lower inode.
878 *
879 * All other metadata changes will be passed right to the lower filesystem,
880 * and we will just update our inode to look like the lower.
881 */
882static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
883{
884 int rc = 0;
885 struct dentry *lower_dentry;
886 struct iattr lower_ia;
887 struct inode *inode;
888 struct inode *lower_inode;
889 struct ecryptfs_crypt_stat *crypt_stat;
890
891 crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
892 if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)) {
893 rc = ecryptfs_init_crypt_stat(crypt_stat);
894 if (rc)
895 return rc;
896 }
897 inode = d_inode(dentry);
898 lower_inode = ecryptfs_inode_to_lower(inode);
899 lower_dentry = ecryptfs_dentry_to_lower(dentry);
900 mutex_lock(&crypt_stat->cs_mutex);
901 if (d_is_dir(dentry))
902 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
903 else if (d_is_reg(dentry)
904 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
905 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
906 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
907
908 mount_crypt_stat = &ecryptfs_superblock_to_private(
909 dentry->d_sb)->mount_crypt_stat;
910 rc = ecryptfs_get_lower_file(dentry, inode);
911 if (rc) {
912 mutex_unlock(&crypt_stat->cs_mutex);
913 goto out;
914 }
915 rc = ecryptfs_read_metadata(dentry);
916 ecryptfs_put_lower_file(inode);
917 if (rc) {
918 if (!(mount_crypt_stat->flags
919 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
920 rc = -EIO;
921 printk(KERN_WARNING "Either the lower file "
922 "is not in a valid eCryptfs format, "
923 "or the key could not be retrieved. "
924 "Plaintext passthrough mode is not "
925 "enabled; returning -EIO\n");
926 mutex_unlock(&crypt_stat->cs_mutex);
927 goto out;
928 }
929 rc = 0;
930 crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
931 | ECRYPTFS_ENCRYPTED);
932 }
933 }
934 mutex_unlock(&crypt_stat->cs_mutex);
935
936 rc = setattr_prepare(dentry, ia);
937 if (rc)
938 goto out;
939 if (ia->ia_valid & ATTR_SIZE) {
940 rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size);
941 if (rc)
942 goto out;
943 }
944
945 memcpy(&lower_ia, ia, sizeof(lower_ia));
946 if (ia->ia_valid & ATTR_FILE)
947 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
948 if (ia->ia_valid & ATTR_SIZE) {
949 rc = truncate_upper(dentry, ia, &lower_ia);
950 if (rc < 0)
951 goto out;
952 }
953
954 /*
955 * mode change is for clearing setuid/setgid bits. Allow lower fs
956 * to interpret this in its own way.
957 */
958 if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
959 lower_ia.ia_valid &= ~ATTR_MODE;
960
961 inode_lock(d_inode(lower_dentry));
962 rc = notify_change(lower_dentry, &lower_ia, NULL);
963 inode_unlock(d_inode(lower_dentry));
964out:
965 fsstack_copy_attr_all(inode, lower_inode);
966 return rc;
967}
968
969static int ecryptfs_getattr_link(const struct path *path, struct kstat *stat,
970 u32 request_mask, unsigned int flags)
971{
972 struct dentry *dentry = path->dentry;
973 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
974 int rc = 0;
975
976 mount_crypt_stat = &ecryptfs_superblock_to_private(
977 dentry->d_sb)->mount_crypt_stat;
978 generic_fillattr(d_inode(dentry), stat);
979 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
980 char *target;
981 size_t targetsiz;
982
983 target = ecryptfs_readlink_lower(dentry, &targetsiz);
984 if (!IS_ERR(target)) {
985 kfree(target);
986 stat->size = targetsiz;
987 } else {
988 rc = PTR_ERR(target);
989 }
990 }
991 return rc;
992}
993
994static int ecryptfs_getattr(const struct path *path, struct kstat *stat,
995 u32 request_mask, unsigned int flags)
996{
997 struct dentry *dentry = path->dentry;
998 struct kstat lower_stat;
999 int rc;
1000
1001 rc = vfs_getattr(ecryptfs_dentry_to_lower_path(dentry), &lower_stat,
1002 request_mask, flags);
1003 if (!rc) {
1004 fsstack_copy_attr_all(d_inode(dentry),
1005 ecryptfs_inode_to_lower(d_inode(dentry)));
1006 generic_fillattr(d_inode(dentry), stat);
1007 stat->blocks = lower_stat.blocks;
1008 }
1009 return rc;
1010}
1011
1012int
1013ecryptfs_setxattr(struct dentry *dentry, struct inode *inode,
1014 const char *name, const void *value,
1015 size_t size, int flags)
1016{
1017 int rc;
1018 struct dentry *lower_dentry;
1019
1020 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1021 if (!(d_inode(lower_dentry)->i_opflags & IOP_XATTR)) {
1022 rc = -EOPNOTSUPP;
1023 goto out;
1024 }
1025 rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1026 if (!rc && inode)
1027 fsstack_copy_attr_all(inode, d_inode(lower_dentry));
1028out:
1029 return rc;
1030}
1031
1032ssize_t
1033ecryptfs_getxattr_lower(struct dentry *lower_dentry, struct inode *lower_inode,
1034 const char *name, void *value, size_t size)
1035{
1036 int rc;
1037
1038 if (!(lower_inode->i_opflags & IOP_XATTR)) {
1039 rc = -EOPNOTSUPP;
1040 goto out;
1041 }
1042 inode_lock(lower_inode);
1043 rc = __vfs_getxattr(lower_dentry, lower_inode, name, value, size);
1044 inode_unlock(lower_inode);
1045out:
1046 return rc;
1047}
1048
1049static ssize_t
1050ecryptfs_getxattr(struct dentry *dentry, struct inode *inode,
1051 const char *name, void *value, size_t size)
1052{
1053 return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
1054 ecryptfs_inode_to_lower(inode),
1055 name, value, size);
1056}
1057
1058static ssize_t
1059ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1060{
1061 int rc = 0;
1062 struct dentry *lower_dentry;
1063
1064 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1065 if (!d_inode(lower_dentry)->i_op->listxattr) {
1066 rc = -EOPNOTSUPP;
1067 goto out;
1068 }
1069 inode_lock(d_inode(lower_dentry));
1070 rc = d_inode(lower_dentry)->i_op->listxattr(lower_dentry, list, size);
1071 inode_unlock(d_inode(lower_dentry));
1072out:
1073 return rc;
1074}
1075
1076static int ecryptfs_removexattr(struct dentry *dentry, struct inode *inode,
1077 const char *name)
1078{
1079 int rc;
1080 struct dentry *lower_dentry;
1081 struct inode *lower_inode;
1082
1083 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1084 lower_inode = ecryptfs_inode_to_lower(inode);
1085 if (!(lower_inode->i_opflags & IOP_XATTR)) {
1086 rc = -EOPNOTSUPP;
1087 goto out;
1088 }
1089 inode_lock(lower_inode);
1090 rc = __vfs_removexattr(lower_dentry, name);
1091 inode_unlock(lower_inode);
1092out:
1093 return rc;
1094}
1095
1096const struct inode_operations ecryptfs_symlink_iops = {
1097 .get_link = ecryptfs_get_link,
1098 .permission = ecryptfs_permission,
1099 .setattr = ecryptfs_setattr,
1100 .getattr = ecryptfs_getattr_link,
1101 .listxattr = ecryptfs_listxattr,
1102};
1103
1104const struct inode_operations ecryptfs_dir_iops = {
1105 .create = ecryptfs_create,
1106 .lookup = ecryptfs_lookup,
1107 .link = ecryptfs_link,
1108 .unlink = ecryptfs_unlink,
1109 .symlink = ecryptfs_symlink,
1110 .mkdir = ecryptfs_mkdir,
1111 .rmdir = ecryptfs_rmdir,
1112 .mknod = ecryptfs_mknod,
1113 .rename = ecryptfs_rename,
1114 .permission = ecryptfs_permission,
1115 .setattr = ecryptfs_setattr,
1116 .listxattr = ecryptfs_listxattr,
1117};
1118
1119const struct inode_operations ecryptfs_main_iops = {
1120 .permission = ecryptfs_permission,
1121 .setattr = ecryptfs_setattr,
1122 .getattr = ecryptfs_getattr,
1123 .listxattr = ecryptfs_listxattr,
1124};
1125
1126static int ecryptfs_xattr_get(const struct xattr_handler *handler,
1127 struct dentry *dentry, struct inode *inode,
1128 const char *name, void *buffer, size_t size)
1129{
1130 return ecryptfs_getxattr(dentry, inode, name, buffer, size);
1131}
1132
1133static int ecryptfs_xattr_set(const struct xattr_handler *handler,
1134 struct dentry *dentry, struct inode *inode,
1135 const char *name, const void *value, size_t size,
1136 int flags)
1137{
1138 if (value)
1139 return ecryptfs_setxattr(dentry, inode, name, value, size, flags);
1140 else {
1141 BUG_ON(flags != XATTR_REPLACE);
1142 return ecryptfs_removexattr(dentry, inode, name);
1143 }
1144}
1145
1146static const struct xattr_handler ecryptfs_xattr_handler = {
1147 .prefix = "", /* match anything */
1148 .get = ecryptfs_xattr_get,
1149 .set = ecryptfs_xattr_set,
1150};
1151
1152const struct xattr_handler *ecryptfs_xattr_handlers[] = {
1153 &ecryptfs_xattr_handler,
1154 NULL
1155};