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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/crypto.h>
33#include <linux/fs_stack.h>
34#include <linux/slab.h>
35#include <linux/xattr.h>
36#include <asm/unaligned.h>
37#include "ecryptfs_kernel.h"
38
39static struct dentry *lock_parent(struct dentry *dentry)
40{
41 struct dentry *dir;
42
43 dir = dget_parent(dentry);
44 mutex_lock_nested(&(dir->d_inode->i_mutex), I_MUTEX_PARENT);
45 return dir;
46}
47
48static void unlock_dir(struct dentry *dir)
49{
50 mutex_unlock(&dir->d_inode->i_mutex);
51 dput(dir);
52}
53
54static int ecryptfs_inode_test(struct inode *inode, void *lower_inode)
55{
56 if (ecryptfs_inode_to_lower(inode) == (struct inode *)lower_inode)
57 return 1;
58 return 0;
59}
60
61static int ecryptfs_inode_set(struct inode *inode, void *opaque)
62{
63 struct inode *lower_inode = opaque;
64
65 ecryptfs_set_inode_lower(inode, lower_inode);
66 fsstack_copy_attr_all(inode, lower_inode);
67 /* i_size will be overwritten for encrypted regular files */
68 fsstack_copy_inode_size(inode, lower_inode);
69 inode->i_ino = lower_inode->i_ino;
70 inode->i_version++;
71 inode->i_mapping->a_ops = &ecryptfs_aops;
72 inode->i_mapping->backing_dev_info = inode->i_sb->s_bdi;
73
74 if (S_ISLNK(inode->i_mode))
75 inode->i_op = &ecryptfs_symlink_iops;
76 else if (S_ISDIR(inode->i_mode))
77 inode->i_op = &ecryptfs_dir_iops;
78 else
79 inode->i_op = &ecryptfs_main_iops;
80
81 if (S_ISDIR(inode->i_mode))
82 inode->i_fop = &ecryptfs_dir_fops;
83 else if (special_file(inode->i_mode))
84 init_special_inode(inode, inode->i_mode, inode->i_rdev);
85 else
86 inode->i_fop = &ecryptfs_main_fops;
87
88 return 0;
89}
90
91static struct inode *__ecryptfs_get_inode(struct inode *lower_inode,
92 struct super_block *sb)
93{
94 struct inode *inode;
95
96 if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb))
97 return ERR_PTR(-EXDEV);
98 if (!igrab(lower_inode))
99 return ERR_PTR(-ESTALE);
100 inode = iget5_locked(sb, (unsigned long)lower_inode,
101 ecryptfs_inode_test, ecryptfs_inode_set,
102 lower_inode);
103 if (!inode) {
104 iput(lower_inode);
105 return ERR_PTR(-EACCES);
106 }
107 if (!(inode->i_state & I_NEW))
108 iput(lower_inode);
109
110 return inode;
111}
112
113struct inode *ecryptfs_get_inode(struct inode *lower_inode,
114 struct super_block *sb)
115{
116 struct inode *inode = __ecryptfs_get_inode(lower_inode, sb);
117
118 if (!IS_ERR(inode) && (inode->i_state & I_NEW))
119 unlock_new_inode(inode);
120
121 return inode;
122}
123
124/**
125 * ecryptfs_interpose
126 * @lower_dentry: Existing dentry in the lower filesystem
127 * @dentry: ecryptfs' dentry
128 * @sb: ecryptfs's super_block
129 *
130 * Interposes upper and lower dentries.
131 *
132 * Returns zero on success; non-zero otherwise
133 */
134static int ecryptfs_interpose(struct dentry *lower_dentry,
135 struct dentry *dentry, struct super_block *sb)
136{
137 struct inode *inode = ecryptfs_get_inode(lower_dentry->d_inode, sb);
138
139 if (IS_ERR(inode))
140 return PTR_ERR(inode);
141 d_instantiate(dentry, inode);
142
143 return 0;
144}
145
146/**
147 * ecryptfs_create_underlying_file
148 * @lower_dir_inode: inode of the parent in the lower fs of the new file
149 * @dentry: New file's dentry
150 * @mode: The mode of the new file
151 *
152 * Creates the file in the lower file system.
153 *
154 * Returns zero on success; non-zero on error condition
155 */
156static int
157ecryptfs_create_underlying_file(struct inode *lower_dir_inode,
158 struct dentry *dentry, int mode)
159{
160 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
161 return vfs_create(lower_dir_inode, lower_dentry, mode, NULL);
162}
163
164/**
165 * ecryptfs_do_create
166 * @directory_inode: inode of the new file's dentry's parent in ecryptfs
167 * @ecryptfs_dentry: New file's dentry in ecryptfs
168 * @mode: The mode of the new file
169 * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
170 *
171 * Creates the underlying file and the eCryptfs inode which will link to
172 * it. It will also update the eCryptfs directory inode to mimic the
173 * stat of the lower directory inode.
174 *
175 * Returns zero on success; non-zero on error condition
176 */
177static int
178ecryptfs_do_create(struct inode *directory_inode,
179 struct dentry *ecryptfs_dentry, int mode)
180{
181 int rc;
182 struct dentry *lower_dentry;
183 struct dentry *lower_dir_dentry;
184
185 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
186 lower_dir_dentry = lock_parent(lower_dentry);
187 if (IS_ERR(lower_dir_dentry)) {
188 ecryptfs_printk(KERN_ERR, "Error locking directory of "
189 "dentry\n");
190 rc = PTR_ERR(lower_dir_dentry);
191 goto out;
192 }
193 rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
194 ecryptfs_dentry, mode);
195 if (rc) {
196 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
197 "rc = [%d]\n", __func__, rc);
198 goto out_lock;
199 }
200 rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
201 directory_inode->i_sb);
202 if (rc) {
203 ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n");
204 goto out_lock;
205 }
206 fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
207 fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode);
208out_lock:
209 unlock_dir(lower_dir_dentry);
210out:
211 return rc;
212}
213
214/**
215 * ecryptfs_initialize_file
216 *
217 * Cause the file to be changed from a basic empty file to an ecryptfs
218 * file with a header and first data page.
219 *
220 * Returns zero on success
221 */
222static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
223{
224 struct ecryptfs_crypt_stat *crypt_stat =
225 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
226 int rc = 0;
227
228 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
229 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
230 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
231 goto out;
232 }
233 ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
234 rc = ecryptfs_new_file_context(ecryptfs_dentry);
235 if (rc) {
236 ecryptfs_printk(KERN_ERR, "Error creating new file "
237 "context; rc = [%d]\n", rc);
238 goto out;
239 }
240 rc = ecryptfs_get_lower_file(ecryptfs_dentry,
241 ecryptfs_dentry->d_inode);
242 if (rc) {
243 printk(KERN_ERR "%s: Error attempting to initialize "
244 "the lower file for the dentry with name "
245 "[%s]; rc = [%d]\n", __func__,
246 ecryptfs_dentry->d_name.name, rc);
247 goto out;
248 }
249 rc = ecryptfs_write_metadata(ecryptfs_dentry);
250 if (rc)
251 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
252 ecryptfs_put_lower_file(ecryptfs_dentry->d_inode);
253out:
254 return rc;
255}
256
257/**
258 * ecryptfs_create
259 * @dir: The inode of the directory in which to create the file.
260 * @dentry: The eCryptfs dentry
261 * @mode: The mode of the new file.
262 * @nd: nameidata
263 *
264 * Creates a new file.
265 *
266 * Returns zero on success; non-zero on error condition
267 */
268static int
269ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
270 int mode, struct nameidata *nd)
271{
272 int rc;
273
274 /* ecryptfs_do_create() calls ecryptfs_interpose() */
275 rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode);
276 if (unlikely(rc)) {
277 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
278 "lower filesystem\n");
279 goto out;
280 }
281 /* At this point, a file exists on "disk"; we need to make sure
282 * that this on disk file is prepared to be an ecryptfs file */
283 rc = ecryptfs_initialize_file(ecryptfs_dentry);
284out:
285 return rc;
286}
287
288static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode)
289{
290 struct ecryptfs_crypt_stat *crypt_stat;
291 int rc;
292
293 rc = ecryptfs_get_lower_file(dentry, inode);
294 if (rc) {
295 printk(KERN_ERR "%s: Error attempting to initialize "
296 "the lower file for the dentry with name "
297 "[%s]; rc = [%d]\n", __func__,
298 dentry->d_name.name, rc);
299 return rc;
300 }
301
302 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
303 /* TODO: lock for crypt_stat comparison */
304 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
305 ecryptfs_set_default_sizes(crypt_stat);
306
307 rc = ecryptfs_read_and_validate_header_region(inode);
308 ecryptfs_put_lower_file(inode);
309 if (rc) {
310 rc = ecryptfs_read_and_validate_xattr_region(dentry, inode);
311 if (!rc)
312 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
313 }
314
315 /* Must return 0 to allow non-eCryptfs files to be looked up, too */
316 return 0;
317}
318
319/**
320 * ecryptfs_lookup_interpose - Dentry interposition for a lookup
321 */
322static int ecryptfs_lookup_interpose(struct dentry *dentry,
323 struct dentry *lower_dentry,
324 struct inode *dir_inode)
325{
326 struct inode *inode, *lower_inode = lower_dentry->d_inode;
327 struct ecryptfs_dentry_info *dentry_info;
328 struct vfsmount *lower_mnt;
329 int rc = 0;
330
331 lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
332 fsstack_copy_attr_atime(dir_inode, lower_dentry->d_parent->d_inode);
333 BUG_ON(!lower_dentry->d_count);
334
335 dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
336 ecryptfs_set_dentry_private(dentry, dentry_info);
337 if (!dentry_info) {
338 printk(KERN_ERR "%s: Out of memory whilst attempting "
339 "to allocate ecryptfs_dentry_info struct\n",
340 __func__);
341 dput(lower_dentry);
342 mntput(lower_mnt);
343 d_drop(dentry);
344 return -ENOMEM;
345 }
346 ecryptfs_set_dentry_lower(dentry, lower_dentry);
347 ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
348
349 if (!lower_dentry->d_inode) {
350 /* We want to add because we couldn't find in lower */
351 d_add(dentry, NULL);
352 return 0;
353 }
354 inode = __ecryptfs_get_inode(lower_inode, dir_inode->i_sb);
355 if (IS_ERR(inode)) {
356 printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
357 __func__, PTR_ERR(inode));
358 return PTR_ERR(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 rc;
365 }
366 }
367
368 if (inode->i_state & I_NEW)
369 unlock_new_inode(inode);
370 d_add(dentry, inode);
371
372 return rc;
373}
374
375/**
376 * ecryptfs_lookup
377 * @ecryptfs_dir_inode: The eCryptfs directory inode
378 * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
379 * @ecryptfs_nd: nameidata; may be NULL
380 *
381 * Find a file on disk. If the file does not exist, then we'll add it to the
382 * dentry cache and continue on to read it from the disk.
383 */
384static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
385 struct dentry *ecryptfs_dentry,
386 struct nameidata *ecryptfs_nd)
387{
388 char *encrypted_and_encoded_name = NULL;
389 size_t encrypted_and_encoded_name_size;
390 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
391 struct dentry *lower_dir_dentry, *lower_dentry;
392 int rc = 0;
393
394 if ((ecryptfs_dentry->d_name.len == 1
395 && !strcmp(ecryptfs_dentry->d_name.name, "."))
396 || (ecryptfs_dentry->d_name.len == 2
397 && !strcmp(ecryptfs_dentry->d_name.name, ".."))) {
398 goto out_d_drop;
399 }
400 lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
401 mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
402 lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name,
403 lower_dir_dentry,
404 ecryptfs_dentry->d_name.len);
405 mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
406 if (IS_ERR(lower_dentry)) {
407 rc = PTR_ERR(lower_dentry);
408 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
409 "[%d] on lower_dentry = [%s]\n", __func__, rc,
410 encrypted_and_encoded_name);
411 goto out_d_drop;
412 }
413 if (lower_dentry->d_inode)
414 goto interpose;
415 mount_crypt_stat = &ecryptfs_superblock_to_private(
416 ecryptfs_dentry->d_sb)->mount_crypt_stat;
417 if (!(mount_crypt_stat
418 && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)))
419 goto interpose;
420 dput(lower_dentry);
421 rc = ecryptfs_encrypt_and_encode_filename(
422 &encrypted_and_encoded_name, &encrypted_and_encoded_name_size,
423 NULL, mount_crypt_stat, ecryptfs_dentry->d_name.name,
424 ecryptfs_dentry->d_name.len);
425 if (rc) {
426 printk(KERN_ERR "%s: Error attempting to encrypt and encode "
427 "filename; rc = [%d]\n", __func__, rc);
428 goto out_d_drop;
429 }
430 mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
431 lower_dentry = lookup_one_len(encrypted_and_encoded_name,
432 lower_dir_dentry,
433 encrypted_and_encoded_name_size);
434 mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
435 if (IS_ERR(lower_dentry)) {
436 rc = PTR_ERR(lower_dentry);
437 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
438 "[%d] on lower_dentry = [%s]\n", __func__, rc,
439 encrypted_and_encoded_name);
440 goto out_d_drop;
441 }
442interpose:
443 rc = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry,
444 ecryptfs_dir_inode);
445 goto out;
446out_d_drop:
447 d_drop(ecryptfs_dentry);
448out:
449 kfree(encrypted_and_encoded_name);
450 return ERR_PTR(rc);
451}
452
453static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
454 struct dentry *new_dentry)
455{
456 struct dentry *lower_old_dentry;
457 struct dentry *lower_new_dentry;
458 struct dentry *lower_dir_dentry;
459 u64 file_size_save;
460 int rc;
461
462 file_size_save = i_size_read(old_dentry->d_inode);
463 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
464 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
465 dget(lower_old_dentry);
466 dget(lower_new_dentry);
467 lower_dir_dentry = lock_parent(lower_new_dentry);
468 rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
469 lower_new_dentry);
470 if (rc || !lower_new_dentry->d_inode)
471 goto out_lock;
472 rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
473 if (rc)
474 goto out_lock;
475 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
476 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
477 old_dentry->d_inode->i_nlink =
478 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
479 i_size_write(new_dentry->d_inode, file_size_save);
480out_lock:
481 unlock_dir(lower_dir_dentry);
482 dput(lower_new_dentry);
483 dput(lower_old_dentry);
484 return rc;
485}
486
487static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
488{
489 int rc = 0;
490 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
491 struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
492 struct dentry *lower_dir_dentry;
493
494 dget(lower_dentry);
495 lower_dir_dentry = lock_parent(lower_dentry);
496 rc = vfs_unlink(lower_dir_inode, lower_dentry);
497 if (rc) {
498 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
499 goto out_unlock;
500 }
501 fsstack_copy_attr_times(dir, lower_dir_inode);
502 dentry->d_inode->i_nlink =
503 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
504 dentry->d_inode->i_ctime = dir->i_ctime;
505 d_drop(dentry);
506out_unlock:
507 unlock_dir(lower_dir_dentry);
508 dput(lower_dentry);
509 return rc;
510}
511
512static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
513 const char *symname)
514{
515 int rc;
516 struct dentry *lower_dentry;
517 struct dentry *lower_dir_dentry;
518 char *encoded_symname;
519 size_t encoded_symlen;
520 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
521
522 lower_dentry = ecryptfs_dentry_to_lower(dentry);
523 dget(lower_dentry);
524 lower_dir_dentry = lock_parent(lower_dentry);
525 mount_crypt_stat = &ecryptfs_superblock_to_private(
526 dir->i_sb)->mount_crypt_stat;
527 rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
528 &encoded_symlen,
529 NULL,
530 mount_crypt_stat, symname,
531 strlen(symname));
532 if (rc)
533 goto out_lock;
534 rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
535 encoded_symname);
536 kfree(encoded_symname);
537 if (rc || !lower_dentry->d_inode)
538 goto out_lock;
539 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
540 if (rc)
541 goto out_lock;
542 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
543 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
544out_lock:
545 unlock_dir(lower_dir_dentry);
546 dput(lower_dentry);
547 if (!dentry->d_inode)
548 d_drop(dentry);
549 return rc;
550}
551
552static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
553{
554 int rc;
555 struct dentry *lower_dentry;
556 struct dentry *lower_dir_dentry;
557
558 lower_dentry = ecryptfs_dentry_to_lower(dentry);
559 lower_dir_dentry = lock_parent(lower_dentry);
560 rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
561 if (rc || !lower_dentry->d_inode)
562 goto out;
563 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
564 if (rc)
565 goto out;
566 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
567 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
568 dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
569out:
570 unlock_dir(lower_dir_dentry);
571 if (!dentry->d_inode)
572 d_drop(dentry);
573 return rc;
574}
575
576static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
577{
578 struct dentry *lower_dentry;
579 struct dentry *lower_dir_dentry;
580 int rc;
581
582 lower_dentry = ecryptfs_dentry_to_lower(dentry);
583 dget(dentry);
584 lower_dir_dentry = lock_parent(lower_dentry);
585 dget(lower_dentry);
586 rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
587 dput(lower_dentry);
588 if (!rc && dentry->d_inode)
589 clear_nlink(dentry->d_inode);
590 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
591 dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
592 unlock_dir(lower_dir_dentry);
593 if (!rc)
594 d_drop(dentry);
595 dput(dentry);
596 return rc;
597}
598
599static int
600ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
601{
602 int rc;
603 struct dentry *lower_dentry;
604 struct dentry *lower_dir_dentry;
605
606 lower_dentry = ecryptfs_dentry_to_lower(dentry);
607 lower_dir_dentry = lock_parent(lower_dentry);
608 rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
609 if (rc || !lower_dentry->d_inode)
610 goto out;
611 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
612 if (rc)
613 goto out;
614 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
615 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
616out:
617 unlock_dir(lower_dir_dentry);
618 if (!dentry->d_inode)
619 d_drop(dentry);
620 return rc;
621}
622
623static int
624ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
625 struct inode *new_dir, struct dentry *new_dentry)
626{
627 int rc;
628 struct dentry *lower_old_dentry;
629 struct dentry *lower_new_dentry;
630 struct dentry *lower_old_dir_dentry;
631 struct dentry *lower_new_dir_dentry;
632 struct dentry *trap = NULL;
633
634 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
635 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
636 dget(lower_old_dentry);
637 dget(lower_new_dentry);
638 lower_old_dir_dentry = dget_parent(lower_old_dentry);
639 lower_new_dir_dentry = dget_parent(lower_new_dentry);
640 trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
641 /* source should not be ancestor of target */
642 if (trap == lower_old_dentry) {
643 rc = -EINVAL;
644 goto out_lock;
645 }
646 /* target should not be ancestor of source */
647 if (trap == lower_new_dentry) {
648 rc = -ENOTEMPTY;
649 goto out_lock;
650 }
651 rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
652 lower_new_dir_dentry->d_inode, lower_new_dentry);
653 if (rc)
654 goto out_lock;
655 fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode);
656 if (new_dir != old_dir)
657 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode);
658out_lock:
659 unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
660 dput(lower_new_dir_dentry);
661 dput(lower_old_dir_dentry);
662 dput(lower_new_dentry);
663 dput(lower_old_dentry);
664 return rc;
665}
666
667static int ecryptfs_readlink_lower(struct dentry *dentry, char **buf,
668 size_t *bufsiz)
669{
670 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
671 char *lower_buf;
672 size_t lower_bufsiz = PATH_MAX;
673 mm_segment_t old_fs;
674 int rc;
675
676 lower_buf = kmalloc(lower_bufsiz, GFP_KERNEL);
677 if (!lower_buf) {
678 rc = -ENOMEM;
679 goto out;
680 }
681 old_fs = get_fs();
682 set_fs(get_ds());
683 rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
684 (char __user *)lower_buf,
685 lower_bufsiz);
686 set_fs(old_fs);
687 if (rc < 0)
688 goto out;
689 lower_bufsiz = rc;
690 rc = ecryptfs_decode_and_decrypt_filename(buf, bufsiz, dentry,
691 lower_buf, lower_bufsiz);
692out:
693 kfree(lower_buf);
694 return rc;
695}
696
697static int
698ecryptfs_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
699{
700 char *kbuf;
701 size_t kbufsiz, copied;
702 int rc;
703
704 rc = ecryptfs_readlink_lower(dentry, &kbuf, &kbufsiz);
705 if (rc)
706 goto out;
707 copied = min_t(size_t, bufsiz, kbufsiz);
708 rc = copy_to_user(buf, kbuf, copied) ? -EFAULT : copied;
709 kfree(kbuf);
710 fsstack_copy_attr_atime(dentry->d_inode,
711 ecryptfs_dentry_to_lower(dentry)->d_inode);
712out:
713 return rc;
714}
715
716static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
717{
718 char *buf;
719 int len = PAGE_SIZE, rc;
720 mm_segment_t old_fs;
721
722 /* Released in ecryptfs_put_link(); only release here on error */
723 buf = kmalloc(len, GFP_KERNEL);
724 if (!buf) {
725 buf = ERR_PTR(-ENOMEM);
726 goto out;
727 }
728 old_fs = get_fs();
729 set_fs(get_ds());
730 rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
731 set_fs(old_fs);
732 if (rc < 0) {
733 kfree(buf);
734 buf = ERR_PTR(rc);
735 } else
736 buf[rc] = '\0';
737out:
738 nd_set_link(nd, buf);
739 return NULL;
740}
741
742static void
743ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
744{
745 char *buf = nd_get_link(nd);
746 if (!IS_ERR(buf)) {
747 /* Free the char* */
748 kfree(buf);
749 }
750}
751
752/**
753 * upper_size_to_lower_size
754 * @crypt_stat: Crypt_stat associated with file
755 * @upper_size: Size of the upper file
756 *
757 * Calculate the required size of the lower file based on the
758 * specified size of the upper file. This calculation is based on the
759 * number of headers in the underlying file and the extent size.
760 *
761 * Returns Calculated size of the lower file.
762 */
763static loff_t
764upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
765 loff_t upper_size)
766{
767 loff_t lower_size;
768
769 lower_size = ecryptfs_lower_header_size(crypt_stat);
770 if (upper_size != 0) {
771 loff_t num_extents;
772
773 num_extents = upper_size >> crypt_stat->extent_shift;
774 if (upper_size & ~crypt_stat->extent_mask)
775 num_extents++;
776 lower_size += (num_extents * crypt_stat->extent_size);
777 }
778 return lower_size;
779}
780
781/**
782 * truncate_upper
783 * @dentry: The ecryptfs layer dentry
784 * @ia: Address of the ecryptfs inode's attributes
785 * @lower_ia: Address of the lower inode's attributes
786 *
787 * Function to handle truncations modifying the size of the file. Note
788 * that the file sizes are interpolated. When expanding, we are simply
789 * writing strings of 0's out. When truncating, we truncate the upper
790 * inode and update the lower_ia according to the page index
791 * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
792 * the caller must use lower_ia in a call to notify_change() to perform
793 * the truncation of the lower inode.
794 *
795 * Returns zero on success; non-zero otherwise
796 */
797static int truncate_upper(struct dentry *dentry, struct iattr *ia,
798 struct iattr *lower_ia)
799{
800 int rc = 0;
801 struct inode *inode = dentry->d_inode;
802 struct ecryptfs_crypt_stat *crypt_stat;
803 loff_t i_size = i_size_read(inode);
804 loff_t lower_size_before_truncate;
805 loff_t lower_size_after_truncate;
806
807 if (unlikely((ia->ia_size == i_size))) {
808 lower_ia->ia_valid &= ~ATTR_SIZE;
809 return 0;
810 }
811 rc = ecryptfs_get_lower_file(dentry, inode);
812 if (rc)
813 return rc;
814 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
815 /* Switch on growing or shrinking file */
816 if (ia->ia_size > i_size) {
817 char zero[] = { 0x00 };
818
819 lower_ia->ia_valid &= ~ATTR_SIZE;
820 /* Write a single 0 at the last position of the file;
821 * this triggers code that will fill in 0's throughout
822 * the intermediate portion of the previous end of the
823 * file and the new and of the file */
824 rc = ecryptfs_write(inode, zero,
825 (ia->ia_size - 1), 1);
826 } else { /* ia->ia_size < i_size_read(inode) */
827 /* We're chopping off all the pages down to the page
828 * in which ia->ia_size is located. Fill in the end of
829 * that page from (ia->ia_size & ~PAGE_CACHE_MASK) to
830 * PAGE_CACHE_SIZE with zeros. */
831 size_t num_zeros = (PAGE_CACHE_SIZE
832 - (ia->ia_size & ~PAGE_CACHE_MASK));
833
834
835 /*
836 * XXX(truncate) this should really happen at the begginning
837 * of ->setattr. But the code is too messy to that as part
838 * of a larger patch. ecryptfs is also totally missing out
839 * on the inode_change_ok check at the beginning of
840 * ->setattr while would include this.
841 */
842 rc = inode_newsize_ok(inode, ia->ia_size);
843 if (rc)
844 goto out;
845
846 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
847 truncate_setsize(inode, ia->ia_size);
848 lower_ia->ia_size = ia->ia_size;
849 lower_ia->ia_valid |= ATTR_SIZE;
850 goto out;
851 }
852 if (num_zeros) {
853 char *zeros_virt;
854
855 zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
856 if (!zeros_virt) {
857 rc = -ENOMEM;
858 goto out;
859 }
860 rc = ecryptfs_write(inode, zeros_virt,
861 ia->ia_size, num_zeros);
862 kfree(zeros_virt);
863 if (rc) {
864 printk(KERN_ERR "Error attempting to zero out "
865 "the remainder of the end page on "
866 "reducing truncate; rc = [%d]\n", rc);
867 goto out;
868 }
869 }
870 truncate_setsize(inode, ia->ia_size);
871 rc = ecryptfs_write_inode_size_to_metadata(inode);
872 if (rc) {
873 printk(KERN_ERR "Problem with "
874 "ecryptfs_write_inode_size_to_metadata; "
875 "rc = [%d]\n", rc);
876 goto out;
877 }
878 /* We are reducing the size of the ecryptfs file, and need to
879 * know if we need to reduce the size of the lower file. */
880 lower_size_before_truncate =
881 upper_size_to_lower_size(crypt_stat, i_size);
882 lower_size_after_truncate =
883 upper_size_to_lower_size(crypt_stat, ia->ia_size);
884 if (lower_size_after_truncate < lower_size_before_truncate) {
885 lower_ia->ia_size = lower_size_after_truncate;
886 lower_ia->ia_valid |= ATTR_SIZE;
887 } else
888 lower_ia->ia_valid &= ~ATTR_SIZE;
889 }
890out:
891 ecryptfs_put_lower_file(inode);
892 return rc;
893}
894
895/**
896 * ecryptfs_truncate
897 * @dentry: The ecryptfs layer dentry
898 * @new_length: The length to expand the file to
899 *
900 * Simple function that handles the truncation of an eCryptfs inode and
901 * its corresponding lower inode.
902 *
903 * Returns zero on success; non-zero otherwise
904 */
905int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
906{
907 struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
908 struct iattr lower_ia = { .ia_valid = 0 };
909 int rc;
910
911 rc = truncate_upper(dentry, &ia, &lower_ia);
912 if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
913 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
914
915 mutex_lock(&lower_dentry->d_inode->i_mutex);
916 rc = notify_change(lower_dentry, &lower_ia);
917 mutex_unlock(&lower_dentry->d_inode->i_mutex);
918 }
919 return rc;
920}
921
922static int
923ecryptfs_permission(struct inode *inode, int mask)
924{
925 return inode_permission(ecryptfs_inode_to_lower(inode), mask);
926}
927
928/**
929 * ecryptfs_setattr
930 * @dentry: dentry handle to the inode to modify
931 * @ia: Structure with flags of what to change and values
932 *
933 * Updates the metadata of an inode. If the update is to the size
934 * i.e. truncation, then ecryptfs_truncate will handle the size modification
935 * of both the ecryptfs inode and the lower inode.
936 *
937 * All other metadata changes will be passed right to the lower filesystem,
938 * and we will just update our inode to look like the lower.
939 */
940static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
941{
942 int rc = 0;
943 struct dentry *lower_dentry;
944 struct iattr lower_ia;
945 struct inode *inode;
946 struct inode *lower_inode;
947 struct ecryptfs_crypt_stat *crypt_stat;
948
949 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
950 if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
951 ecryptfs_init_crypt_stat(crypt_stat);
952 inode = dentry->d_inode;
953 lower_inode = ecryptfs_inode_to_lower(inode);
954 lower_dentry = ecryptfs_dentry_to_lower(dentry);
955 mutex_lock(&crypt_stat->cs_mutex);
956 if (S_ISDIR(dentry->d_inode->i_mode))
957 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
958 else if (S_ISREG(dentry->d_inode->i_mode)
959 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
960 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
961 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
962
963 mount_crypt_stat = &ecryptfs_superblock_to_private(
964 dentry->d_sb)->mount_crypt_stat;
965 rc = ecryptfs_get_lower_file(dentry, inode);
966 if (rc) {
967 mutex_unlock(&crypt_stat->cs_mutex);
968 goto out;
969 }
970 rc = ecryptfs_read_metadata(dentry);
971 ecryptfs_put_lower_file(inode);
972 if (rc) {
973 if (!(mount_crypt_stat->flags
974 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
975 rc = -EIO;
976 printk(KERN_WARNING "Either the lower file "
977 "is not in a valid eCryptfs format, "
978 "or the key could not be retrieved. "
979 "Plaintext passthrough mode is not "
980 "enabled; returning -EIO\n");
981 mutex_unlock(&crypt_stat->cs_mutex);
982 goto out;
983 }
984 rc = 0;
985 crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
986 | ECRYPTFS_ENCRYPTED);
987 }
988 }
989 mutex_unlock(&crypt_stat->cs_mutex);
990 if (S_ISREG(inode->i_mode)) {
991 rc = filemap_write_and_wait(inode->i_mapping);
992 if (rc)
993 goto out;
994 fsstack_copy_attr_all(inode, lower_inode);
995 }
996 memcpy(&lower_ia, ia, sizeof(lower_ia));
997 if (ia->ia_valid & ATTR_FILE)
998 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
999 if (ia->ia_valid & ATTR_SIZE) {
1000 rc = truncate_upper(dentry, ia, &lower_ia);
1001 if (rc < 0)
1002 goto out;
1003 }
1004
1005 /*
1006 * mode change is for clearing setuid/setgid bits. Allow lower fs
1007 * to interpret this in its own way.
1008 */
1009 if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
1010 lower_ia.ia_valid &= ~ATTR_MODE;
1011
1012 mutex_lock(&lower_dentry->d_inode->i_mutex);
1013 rc = notify_change(lower_dentry, &lower_ia);
1014 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1015out:
1016 fsstack_copy_attr_all(inode, lower_inode);
1017 return rc;
1018}
1019
1020int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
1021 struct kstat *stat)
1022{
1023 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
1024 int rc = 0;
1025
1026 mount_crypt_stat = &ecryptfs_superblock_to_private(
1027 dentry->d_sb)->mount_crypt_stat;
1028 generic_fillattr(dentry->d_inode, stat);
1029 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
1030 char *target;
1031 size_t targetsiz;
1032
1033 rc = ecryptfs_readlink_lower(dentry, &target, &targetsiz);
1034 if (!rc) {
1035 kfree(target);
1036 stat->size = targetsiz;
1037 }
1038 }
1039 return rc;
1040}
1041
1042int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
1043 struct kstat *stat)
1044{
1045 struct kstat lower_stat;
1046 int rc;
1047
1048 rc = vfs_getattr(ecryptfs_dentry_to_lower_mnt(dentry),
1049 ecryptfs_dentry_to_lower(dentry), &lower_stat);
1050 if (!rc) {
1051 fsstack_copy_attr_all(dentry->d_inode,
1052 ecryptfs_inode_to_lower(dentry->d_inode));
1053 generic_fillattr(dentry->d_inode, stat);
1054 stat->blocks = lower_stat.blocks;
1055 }
1056 return rc;
1057}
1058
1059int
1060ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
1061 size_t size, int flags)
1062{
1063 int rc = 0;
1064 struct dentry *lower_dentry;
1065
1066 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1067 if (!lower_dentry->d_inode->i_op->setxattr) {
1068 rc = -EOPNOTSUPP;
1069 goto out;
1070 }
1071
1072 rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1073out:
1074 return rc;
1075}
1076
1077ssize_t
1078ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
1079 void *value, size_t size)
1080{
1081 int rc = 0;
1082
1083 if (!lower_dentry->d_inode->i_op->getxattr) {
1084 rc = -EOPNOTSUPP;
1085 goto out;
1086 }
1087 mutex_lock(&lower_dentry->d_inode->i_mutex);
1088 rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
1089 size);
1090 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1091out:
1092 return rc;
1093}
1094
1095static ssize_t
1096ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
1097 size_t size)
1098{
1099 return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
1100 value, size);
1101}
1102
1103static ssize_t
1104ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1105{
1106 int rc = 0;
1107 struct dentry *lower_dentry;
1108
1109 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1110 if (!lower_dentry->d_inode->i_op->listxattr) {
1111 rc = -EOPNOTSUPP;
1112 goto out;
1113 }
1114 mutex_lock(&lower_dentry->d_inode->i_mutex);
1115 rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1116 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1117out:
1118 return rc;
1119}
1120
1121static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1122{
1123 int rc = 0;
1124 struct dentry *lower_dentry;
1125
1126 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1127 if (!lower_dentry->d_inode->i_op->removexattr) {
1128 rc = -EOPNOTSUPP;
1129 goto out;
1130 }
1131 mutex_lock(&lower_dentry->d_inode->i_mutex);
1132 rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1133 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1134out:
1135 return rc;
1136}
1137
1138const struct inode_operations ecryptfs_symlink_iops = {
1139 .readlink = ecryptfs_readlink,
1140 .follow_link = ecryptfs_follow_link,
1141 .put_link = ecryptfs_put_link,
1142 .permission = ecryptfs_permission,
1143 .setattr = ecryptfs_setattr,
1144 .getattr = ecryptfs_getattr_link,
1145 .setxattr = ecryptfs_setxattr,
1146 .getxattr = ecryptfs_getxattr,
1147 .listxattr = ecryptfs_listxattr,
1148 .removexattr = ecryptfs_removexattr
1149};
1150
1151const struct inode_operations ecryptfs_dir_iops = {
1152 .create = ecryptfs_create,
1153 .lookup = ecryptfs_lookup,
1154 .link = ecryptfs_link,
1155 .unlink = ecryptfs_unlink,
1156 .symlink = ecryptfs_symlink,
1157 .mkdir = ecryptfs_mkdir,
1158 .rmdir = ecryptfs_rmdir,
1159 .mknod = ecryptfs_mknod,
1160 .rename = ecryptfs_rename,
1161 .permission = ecryptfs_permission,
1162 .setattr = ecryptfs_setattr,
1163 .setxattr = ecryptfs_setxattr,
1164 .getxattr = ecryptfs_getxattr,
1165 .listxattr = ecryptfs_listxattr,
1166 .removexattr = ecryptfs_removexattr
1167};
1168
1169const struct inode_operations ecryptfs_main_iops = {
1170 .permission = ecryptfs_permission,
1171 .setattr = ecryptfs_setattr,
1172 .getattr = ecryptfs_getattr,
1173 .setxattr = ecryptfs_setxattr,
1174 .getxattr = ecryptfs_getxattr,
1175 .listxattr = ecryptfs_listxattr,
1176 .removexattr = ecryptfs_removexattr
1177};
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 <linux/fileattr.h>
22#include <asm/unaligned.h>
23#include "ecryptfs_kernel.h"
24
25static int lock_parent(struct dentry *dentry,
26 struct dentry **lower_dentry,
27 struct inode **lower_dir)
28{
29 struct dentry *lower_dir_dentry;
30
31 lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
32 *lower_dir = d_inode(lower_dir_dentry);
33 *lower_dentry = ecryptfs_dentry_to_lower(dentry);
34
35 inode_lock_nested(*lower_dir, I_MUTEX_PARENT);
36 return (*lower_dentry)->d_parent == lower_dir_dentry ? 0 : -EINVAL;
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;
131 struct inode *lower_dir;
132 int rc;
133
134 rc = lock_parent(dentry, &lower_dentry, &lower_dir);
135 dget(lower_dentry); // don't even try to make the lower negative
136 if (!rc) {
137 if (d_unhashed(lower_dentry))
138 rc = -EINVAL;
139 else
140 rc = vfs_unlink(&init_user_ns, lower_dir, lower_dentry,
141 NULL);
142 }
143 if (rc) {
144 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
145 goto out_unlock;
146 }
147 fsstack_copy_attr_times(dir, lower_dir);
148 set_nlink(inode, ecryptfs_inode_to_lower(inode)->i_nlink);
149 inode->i_ctime = dir->i_ctime;
150out_unlock:
151 dput(lower_dentry);
152 inode_unlock(lower_dir);
153 if (!rc)
154 d_drop(dentry);
155 return rc;
156}
157
158/**
159 * ecryptfs_do_create
160 * @directory_inode: inode of the new file's dentry's parent in ecryptfs
161 * @ecryptfs_dentry: New file's dentry in ecryptfs
162 * @mode: The mode of the new file
163 *
164 * Creates the underlying file and the eCryptfs inode which will link to
165 * it. It will also update the eCryptfs directory inode to mimic the
166 * stat of the lower directory inode.
167 *
168 * Returns the new eCryptfs inode on success; an ERR_PTR on error condition
169 */
170static struct inode *
171ecryptfs_do_create(struct inode *directory_inode,
172 struct dentry *ecryptfs_dentry, umode_t mode)
173{
174 int rc;
175 struct dentry *lower_dentry;
176 struct inode *lower_dir;
177 struct inode *inode;
178
179 rc = lock_parent(ecryptfs_dentry, &lower_dentry, &lower_dir);
180 if (!rc)
181 rc = vfs_create(&init_user_ns, lower_dir,
182 lower_dentry, mode, true);
183 if (rc) {
184 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
185 "rc = [%d]\n", __func__, rc);
186 inode = ERR_PTR(rc);
187 goto out_lock;
188 }
189 inode = __ecryptfs_get_inode(d_inode(lower_dentry),
190 directory_inode->i_sb);
191 if (IS_ERR(inode)) {
192 vfs_unlink(&init_user_ns, lower_dir, lower_dentry, NULL);
193 goto out_lock;
194 }
195 fsstack_copy_attr_times(directory_inode, lower_dir);
196 fsstack_copy_inode_size(directory_inode, lower_dir);
197out_lock:
198 inode_unlock(lower_dir);
199 return inode;
200}
201
202/*
203 * ecryptfs_initialize_file
204 *
205 * Cause the file to be changed from a basic empty file to an ecryptfs
206 * file with a header and first data page.
207 *
208 * Returns zero on success
209 */
210int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry,
211 struct inode *ecryptfs_inode)
212{
213 struct ecryptfs_crypt_stat *crypt_stat =
214 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
215 int rc = 0;
216
217 if (S_ISDIR(ecryptfs_inode->i_mode)) {
218 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
219 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
220 goto out;
221 }
222 ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
223 rc = ecryptfs_new_file_context(ecryptfs_inode);
224 if (rc) {
225 ecryptfs_printk(KERN_ERR, "Error creating new file "
226 "context; rc = [%d]\n", rc);
227 goto out;
228 }
229 rc = ecryptfs_get_lower_file(ecryptfs_dentry, ecryptfs_inode);
230 if (rc) {
231 printk(KERN_ERR "%s: Error attempting to initialize "
232 "the lower file for the dentry with name "
233 "[%pd]; rc = [%d]\n", __func__,
234 ecryptfs_dentry, rc);
235 goto out;
236 }
237 rc = ecryptfs_write_metadata(ecryptfs_dentry, ecryptfs_inode);
238 if (rc)
239 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
240 ecryptfs_put_lower_file(ecryptfs_inode);
241out:
242 return rc;
243}
244
245/*
246 * ecryptfs_create
247 * @mode: The mode of the new file.
248 *
249 * Creates a new file.
250 *
251 * Returns zero on success; non-zero on error condition
252 */
253static int
254ecryptfs_create(struct user_namespace *mnt_userns,
255 struct inode *directory_inode, struct dentry *ecryptfs_dentry,
256 umode_t mode, bool excl)
257{
258 struct inode *ecryptfs_inode;
259 int rc;
260
261 ecryptfs_inode = ecryptfs_do_create(directory_inode, ecryptfs_dentry,
262 mode);
263 if (IS_ERR(ecryptfs_inode)) {
264 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
265 "lower filesystem\n");
266 rc = PTR_ERR(ecryptfs_inode);
267 goto out;
268 }
269 /* At this point, a file exists on "disk"; we need to make sure
270 * that this on disk file is prepared to be an ecryptfs file */
271 rc = ecryptfs_initialize_file(ecryptfs_dentry, ecryptfs_inode);
272 if (rc) {
273 ecryptfs_do_unlink(directory_inode, ecryptfs_dentry,
274 ecryptfs_inode);
275 iget_failed(ecryptfs_inode);
276 goto out;
277 }
278 d_instantiate_new(ecryptfs_dentry, ecryptfs_inode);
279out:
280 return rc;
281}
282
283static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode)
284{
285 struct ecryptfs_crypt_stat *crypt_stat;
286 int rc;
287
288 rc = ecryptfs_get_lower_file(dentry, inode);
289 if (rc) {
290 printk(KERN_ERR "%s: Error attempting to initialize "
291 "the lower file for the dentry with name "
292 "[%pd]; rc = [%d]\n", __func__,
293 dentry, rc);
294 return rc;
295 }
296
297 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
298 /* TODO: lock for crypt_stat comparison */
299 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
300 ecryptfs_set_default_sizes(crypt_stat);
301
302 rc = ecryptfs_read_and_validate_header_region(inode);
303 ecryptfs_put_lower_file(inode);
304 if (rc) {
305 rc = ecryptfs_read_and_validate_xattr_region(dentry, inode);
306 if (!rc)
307 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
308 }
309
310 /* Must return 0 to allow non-eCryptfs files to be looked up, too */
311 return 0;
312}
313
314/*
315 * ecryptfs_lookup_interpose - Dentry interposition for a lookup
316 */
317static struct dentry *ecryptfs_lookup_interpose(struct dentry *dentry,
318 struct dentry *lower_dentry)
319{
320 struct path *path = ecryptfs_dentry_to_lower_path(dentry->d_parent);
321 struct inode *inode, *lower_inode;
322 struct ecryptfs_dentry_info *dentry_info;
323 int rc = 0;
324
325 dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
326 if (!dentry_info) {
327 dput(lower_dentry);
328 return ERR_PTR(-ENOMEM);
329 }
330
331 fsstack_copy_attr_atime(d_inode(dentry->d_parent),
332 d_inode(path->dentry));
333 BUG_ON(!d_count(lower_dentry));
334
335 ecryptfs_set_dentry_private(dentry, dentry_info);
336 dentry_info->lower_path.mnt = mntget(path->mnt);
337 dentry_info->lower_path.dentry = lower_dentry;
338
339 /*
340 * negative dentry can go positive under us here - its parent is not
341 * locked. That's OK and that could happen just as we return from
342 * ecryptfs_lookup() anyway. Just need to be careful and fetch
343 * ->d_inode only once - it's not stable here.
344 */
345 lower_inode = READ_ONCE(lower_dentry->d_inode);
346
347 if (!lower_inode) {
348 /* We want to add because we couldn't find in lower */
349 d_add(dentry, NULL);
350 return NULL;
351 }
352 inode = __ecryptfs_get_inode(lower_inode, dentry->d_sb);
353 if (IS_ERR(inode)) {
354 printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
355 __func__, PTR_ERR(inode));
356 return ERR_CAST(inode);
357 }
358 if (S_ISREG(inode->i_mode)) {
359 rc = ecryptfs_i_size_read(dentry, inode);
360 if (rc) {
361 make_bad_inode(inode);
362 return ERR_PTR(rc);
363 }
364 }
365
366 if (inode->i_state & I_NEW)
367 unlock_new_inode(inode);
368 return d_splice_alias(inode, dentry);
369}
370
371/**
372 * ecryptfs_lookup
373 * @ecryptfs_dir_inode: The eCryptfs directory inode
374 * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
375 * @flags: lookup flags
376 *
377 * Find a file on disk. If the file does not exist, then we'll add it to the
378 * dentry cache and continue on to read it from the disk.
379 */
380static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
381 struct dentry *ecryptfs_dentry,
382 unsigned int flags)
383{
384 char *encrypted_and_encoded_name = NULL;
385 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
386 struct dentry *lower_dir_dentry, *lower_dentry;
387 const char *name = ecryptfs_dentry->d_name.name;
388 size_t len = ecryptfs_dentry->d_name.len;
389 struct dentry *res;
390 int rc = 0;
391
392 lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
393
394 mount_crypt_stat = &ecryptfs_superblock_to_private(
395 ecryptfs_dentry->d_sb)->mount_crypt_stat;
396 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
397 rc = ecryptfs_encrypt_and_encode_filename(
398 &encrypted_and_encoded_name, &len,
399 mount_crypt_stat, name, len);
400 if (rc) {
401 printk(KERN_ERR "%s: Error attempting to encrypt and encode "
402 "filename; rc = [%d]\n", __func__, rc);
403 return ERR_PTR(rc);
404 }
405 name = encrypted_and_encoded_name;
406 }
407
408 lower_dentry = lookup_one_len_unlocked(name, lower_dir_dentry, len);
409 if (IS_ERR(lower_dentry)) {
410 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
411 "[%ld] on lower_dentry = [%s]\n", __func__,
412 PTR_ERR(lower_dentry),
413 name);
414 res = ERR_CAST(lower_dentry);
415 } else {
416 res = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry);
417 }
418 kfree(encrypted_and_encoded_name);
419 return res;
420}
421
422static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
423 struct dentry *new_dentry)
424{
425 struct dentry *lower_old_dentry;
426 struct dentry *lower_new_dentry;
427 struct inode *lower_dir;
428 u64 file_size_save;
429 int rc;
430
431 file_size_save = i_size_read(d_inode(old_dentry));
432 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
433 rc = lock_parent(new_dentry, &lower_new_dentry, &lower_dir);
434 if (!rc)
435 rc = vfs_link(lower_old_dentry, &init_user_ns, lower_dir,
436 lower_new_dentry, NULL);
437 if (rc || d_really_is_negative(lower_new_dentry))
438 goto out_lock;
439 rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
440 if (rc)
441 goto out_lock;
442 fsstack_copy_attr_times(dir, lower_dir);
443 fsstack_copy_inode_size(dir, lower_dir);
444 set_nlink(d_inode(old_dentry),
445 ecryptfs_inode_to_lower(d_inode(old_dentry))->i_nlink);
446 i_size_write(d_inode(new_dentry), file_size_save);
447out_lock:
448 inode_unlock(lower_dir);
449 return rc;
450}
451
452static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
453{
454 return ecryptfs_do_unlink(dir, dentry, d_inode(dentry));
455}
456
457static int ecryptfs_symlink(struct user_namespace *mnt_userns,
458 struct inode *dir, struct dentry *dentry,
459 const char *symname)
460{
461 int rc;
462 struct dentry *lower_dentry;
463 struct inode *lower_dir;
464 char *encoded_symname;
465 size_t encoded_symlen;
466 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
467
468 rc = lock_parent(dentry, &lower_dentry, &lower_dir);
469 if (rc)
470 goto out_lock;
471 mount_crypt_stat = &ecryptfs_superblock_to_private(
472 dir->i_sb)->mount_crypt_stat;
473 rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
474 &encoded_symlen,
475 mount_crypt_stat, symname,
476 strlen(symname));
477 if (rc)
478 goto out_lock;
479 rc = vfs_symlink(&init_user_ns, lower_dir, lower_dentry,
480 encoded_symname);
481 kfree(encoded_symname);
482 if (rc || d_really_is_negative(lower_dentry))
483 goto out_lock;
484 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
485 if (rc)
486 goto out_lock;
487 fsstack_copy_attr_times(dir, lower_dir);
488 fsstack_copy_inode_size(dir, lower_dir);
489out_lock:
490 inode_unlock(lower_dir);
491 if (d_really_is_negative(dentry))
492 d_drop(dentry);
493 return rc;
494}
495
496static int ecryptfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
497 struct dentry *dentry, umode_t mode)
498{
499 int rc;
500 struct dentry *lower_dentry;
501 struct inode *lower_dir;
502
503 rc = lock_parent(dentry, &lower_dentry, &lower_dir);
504 if (!rc)
505 rc = vfs_mkdir(&init_user_ns, lower_dir,
506 lower_dentry, mode);
507 if (rc || d_really_is_negative(lower_dentry))
508 goto out;
509 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
510 if (rc)
511 goto out;
512 fsstack_copy_attr_times(dir, lower_dir);
513 fsstack_copy_inode_size(dir, lower_dir);
514 set_nlink(dir, lower_dir->i_nlink);
515out:
516 inode_unlock(lower_dir);
517 if (d_really_is_negative(dentry))
518 d_drop(dentry);
519 return rc;
520}
521
522static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
523{
524 struct dentry *lower_dentry;
525 struct inode *lower_dir;
526 int rc;
527
528 rc = lock_parent(dentry, &lower_dentry, &lower_dir);
529 dget(lower_dentry); // don't even try to make the lower negative
530 if (!rc) {
531 if (d_unhashed(lower_dentry))
532 rc = -EINVAL;
533 else
534 rc = vfs_rmdir(&init_user_ns, lower_dir, lower_dentry);
535 }
536 if (!rc) {
537 clear_nlink(d_inode(dentry));
538 fsstack_copy_attr_times(dir, lower_dir);
539 set_nlink(dir, lower_dir->i_nlink);
540 }
541 dput(lower_dentry);
542 inode_unlock(lower_dir);
543 if (!rc)
544 d_drop(dentry);
545 return rc;
546}
547
548static int
549ecryptfs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
550 struct dentry *dentry, umode_t mode, dev_t dev)
551{
552 int rc;
553 struct dentry *lower_dentry;
554 struct inode *lower_dir;
555
556 rc = lock_parent(dentry, &lower_dentry, &lower_dir);
557 if (!rc)
558 rc = vfs_mknod(&init_user_ns, lower_dir,
559 lower_dentry, mode, dev);
560 if (rc || d_really_is_negative(lower_dentry))
561 goto out;
562 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
563 if (rc)
564 goto out;
565 fsstack_copy_attr_times(dir, lower_dir);
566 fsstack_copy_inode_size(dir, lower_dir);
567out:
568 inode_unlock(lower_dir);
569 if (d_really_is_negative(dentry))
570 d_drop(dentry);
571 return rc;
572}
573
574static int
575ecryptfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
576 struct dentry *old_dentry, struct inode *new_dir,
577 struct dentry *new_dentry, unsigned int flags)
578{
579 int rc;
580 struct dentry *lower_old_dentry;
581 struct dentry *lower_new_dentry;
582 struct dentry *lower_old_dir_dentry;
583 struct dentry *lower_new_dir_dentry;
584 struct dentry *trap;
585 struct inode *target_inode;
586 struct renamedata rd = {};
587
588 if (flags)
589 return -EINVAL;
590
591 lower_old_dir_dentry = ecryptfs_dentry_to_lower(old_dentry->d_parent);
592 lower_new_dir_dentry = ecryptfs_dentry_to_lower(new_dentry->d_parent);
593
594 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
595 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
596
597 target_inode = d_inode(new_dentry);
598
599 trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
600 dget(lower_new_dentry);
601 rc = -EINVAL;
602 if (lower_old_dentry->d_parent != lower_old_dir_dentry)
603 goto out_lock;
604 if (lower_new_dentry->d_parent != lower_new_dir_dentry)
605 goto out_lock;
606 if (d_unhashed(lower_old_dentry) || d_unhashed(lower_new_dentry))
607 goto out_lock;
608 /* source should not be ancestor of target */
609 if (trap == lower_old_dentry)
610 goto out_lock;
611 /* target should not be ancestor of source */
612 if (trap == lower_new_dentry) {
613 rc = -ENOTEMPTY;
614 goto out_lock;
615 }
616
617 rd.old_mnt_userns = &init_user_ns;
618 rd.old_dir = d_inode(lower_old_dir_dentry);
619 rd.old_dentry = lower_old_dentry;
620 rd.new_mnt_userns = &init_user_ns;
621 rd.new_dir = d_inode(lower_new_dir_dentry);
622 rd.new_dentry = lower_new_dentry;
623 rc = vfs_rename(&rd);
624 if (rc)
625 goto out_lock;
626 if (target_inode)
627 fsstack_copy_attr_all(target_inode,
628 ecryptfs_inode_to_lower(target_inode));
629 fsstack_copy_attr_all(new_dir, d_inode(lower_new_dir_dentry));
630 if (new_dir != old_dir)
631 fsstack_copy_attr_all(old_dir, d_inode(lower_old_dir_dentry));
632out_lock:
633 dput(lower_new_dentry);
634 unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
635 return rc;
636}
637
638static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
639{
640 DEFINE_DELAYED_CALL(done);
641 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
642 const char *link;
643 char *buf;
644 int rc;
645
646 link = vfs_get_link(lower_dentry, &done);
647 if (IS_ERR(link))
648 return ERR_CAST(link);
649
650 rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb,
651 link, strlen(link));
652 do_delayed_call(&done);
653 if (rc)
654 return ERR_PTR(rc);
655
656 return buf;
657}
658
659static const char *ecryptfs_get_link(struct dentry *dentry,
660 struct inode *inode,
661 struct delayed_call *done)
662{
663 size_t len;
664 char *buf;
665
666 if (!dentry)
667 return ERR_PTR(-ECHILD);
668
669 buf = ecryptfs_readlink_lower(dentry, &len);
670 if (IS_ERR(buf))
671 return buf;
672 fsstack_copy_attr_atime(d_inode(dentry),
673 d_inode(ecryptfs_dentry_to_lower(dentry)));
674 buf[len] = '\0';
675 set_delayed_call(done, kfree_link, buf);
676 return buf;
677}
678
679/**
680 * upper_size_to_lower_size
681 * @crypt_stat: Crypt_stat associated with file
682 * @upper_size: Size of the upper file
683 *
684 * Calculate the required size of the lower file based on the
685 * specified size of the upper file. This calculation is based on the
686 * number of headers in the underlying file and the extent size.
687 *
688 * Returns Calculated size of the lower file.
689 */
690static loff_t
691upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
692 loff_t upper_size)
693{
694 loff_t lower_size;
695
696 lower_size = ecryptfs_lower_header_size(crypt_stat);
697 if (upper_size != 0) {
698 loff_t num_extents;
699
700 num_extents = upper_size >> crypt_stat->extent_shift;
701 if (upper_size & ~crypt_stat->extent_mask)
702 num_extents++;
703 lower_size += (num_extents * crypt_stat->extent_size);
704 }
705 return lower_size;
706}
707
708/**
709 * truncate_upper
710 * @dentry: The ecryptfs layer dentry
711 * @ia: Address of the ecryptfs inode's attributes
712 * @lower_ia: Address of the lower inode's attributes
713 *
714 * Function to handle truncations modifying the size of the file. Note
715 * that the file sizes are interpolated. When expanding, we are simply
716 * writing strings of 0's out. When truncating, we truncate the upper
717 * inode and update the lower_ia according to the page index
718 * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
719 * the caller must use lower_ia in a call to notify_change() to perform
720 * the truncation of the lower inode.
721 *
722 * Returns zero on success; non-zero otherwise
723 */
724static int truncate_upper(struct dentry *dentry, struct iattr *ia,
725 struct iattr *lower_ia)
726{
727 int rc = 0;
728 struct inode *inode = d_inode(dentry);
729 struct ecryptfs_crypt_stat *crypt_stat;
730 loff_t i_size = i_size_read(inode);
731 loff_t lower_size_before_truncate;
732 loff_t lower_size_after_truncate;
733
734 if (unlikely((ia->ia_size == i_size))) {
735 lower_ia->ia_valid &= ~ATTR_SIZE;
736 return 0;
737 }
738 rc = ecryptfs_get_lower_file(dentry, inode);
739 if (rc)
740 return rc;
741 crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
742 /* Switch on growing or shrinking file */
743 if (ia->ia_size > i_size) {
744 char zero[] = { 0x00 };
745
746 lower_ia->ia_valid &= ~ATTR_SIZE;
747 /* Write a single 0 at the last position of the file;
748 * this triggers code that will fill in 0's throughout
749 * the intermediate portion of the previous end of the
750 * file and the new and of the file */
751 rc = ecryptfs_write(inode, zero,
752 (ia->ia_size - 1), 1);
753 } else { /* ia->ia_size < i_size_read(inode) */
754 /* We're chopping off all the pages down to the page
755 * in which ia->ia_size is located. Fill in the end of
756 * that page from (ia->ia_size & ~PAGE_MASK) to
757 * PAGE_SIZE with zeros. */
758 size_t num_zeros = (PAGE_SIZE
759 - (ia->ia_size & ~PAGE_MASK));
760
761 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
762 truncate_setsize(inode, ia->ia_size);
763 lower_ia->ia_size = ia->ia_size;
764 lower_ia->ia_valid |= ATTR_SIZE;
765 goto out;
766 }
767 if (num_zeros) {
768 char *zeros_virt;
769
770 zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
771 if (!zeros_virt) {
772 rc = -ENOMEM;
773 goto out;
774 }
775 rc = ecryptfs_write(inode, zeros_virt,
776 ia->ia_size, num_zeros);
777 kfree(zeros_virt);
778 if (rc) {
779 printk(KERN_ERR "Error attempting to zero out "
780 "the remainder of the end page on "
781 "reducing truncate; rc = [%d]\n", rc);
782 goto out;
783 }
784 }
785 truncate_setsize(inode, ia->ia_size);
786 rc = ecryptfs_write_inode_size_to_metadata(inode);
787 if (rc) {
788 printk(KERN_ERR "Problem with "
789 "ecryptfs_write_inode_size_to_metadata; "
790 "rc = [%d]\n", rc);
791 goto out;
792 }
793 /* We are reducing the size of the ecryptfs file, and need to
794 * know if we need to reduce the size of the lower file. */
795 lower_size_before_truncate =
796 upper_size_to_lower_size(crypt_stat, i_size);
797 lower_size_after_truncate =
798 upper_size_to_lower_size(crypt_stat, ia->ia_size);
799 if (lower_size_after_truncate < lower_size_before_truncate) {
800 lower_ia->ia_size = lower_size_after_truncate;
801 lower_ia->ia_valid |= ATTR_SIZE;
802 } else
803 lower_ia->ia_valid &= ~ATTR_SIZE;
804 }
805out:
806 ecryptfs_put_lower_file(inode);
807 return rc;
808}
809
810static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset)
811{
812 struct ecryptfs_crypt_stat *crypt_stat;
813 loff_t lower_oldsize, lower_newsize;
814
815 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
816 lower_oldsize = upper_size_to_lower_size(crypt_stat,
817 i_size_read(inode));
818 lower_newsize = upper_size_to_lower_size(crypt_stat, offset);
819 if (lower_newsize > lower_oldsize) {
820 /*
821 * The eCryptfs inode and the new *lower* size are mixed here
822 * because we may not have the lower i_mutex held and/or it may
823 * not be appropriate to call inode_newsize_ok() with inodes
824 * from other filesystems.
825 */
826 return inode_newsize_ok(inode, lower_newsize);
827 }
828
829 return 0;
830}
831
832/**
833 * ecryptfs_truncate
834 * @dentry: The ecryptfs layer dentry
835 * @new_length: The length to expand the file to
836 *
837 * Simple function that handles the truncation of an eCryptfs inode and
838 * its corresponding lower inode.
839 *
840 * Returns zero on success; non-zero otherwise
841 */
842int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
843{
844 struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
845 struct iattr lower_ia = { .ia_valid = 0 };
846 int rc;
847
848 rc = ecryptfs_inode_newsize_ok(d_inode(dentry), new_length);
849 if (rc)
850 return rc;
851
852 rc = truncate_upper(dentry, &ia, &lower_ia);
853 if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
854 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
855
856 inode_lock(d_inode(lower_dentry));
857 rc = notify_change(&init_user_ns, lower_dentry,
858 &lower_ia, NULL);
859 inode_unlock(d_inode(lower_dentry));
860 }
861 return rc;
862}
863
864static int
865ecryptfs_permission(struct user_namespace *mnt_userns, struct inode *inode,
866 int mask)
867{
868 return inode_permission(&init_user_ns,
869 ecryptfs_inode_to_lower(inode), mask);
870}
871
872/**
873 * ecryptfs_setattr
874 * @mnt_userns: user namespace of the target mount
875 * @dentry: dentry handle to the inode to modify
876 * @ia: Structure with flags of what to change and values
877 *
878 * Updates the metadata of an inode. If the update is to the size
879 * i.e. truncation, then ecryptfs_truncate will handle the size modification
880 * of both the ecryptfs inode and the lower inode.
881 *
882 * All other metadata changes will be passed right to the lower filesystem,
883 * and we will just update our inode to look like the lower.
884 */
885static int ecryptfs_setattr(struct user_namespace *mnt_userns,
886 struct dentry *dentry, struct iattr *ia)
887{
888 int rc = 0;
889 struct dentry *lower_dentry;
890 struct iattr lower_ia;
891 struct inode *inode;
892 struct inode *lower_inode;
893 struct ecryptfs_crypt_stat *crypt_stat;
894
895 crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
896 if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)) {
897 rc = ecryptfs_init_crypt_stat(crypt_stat);
898 if (rc)
899 return rc;
900 }
901 inode = d_inode(dentry);
902 lower_inode = ecryptfs_inode_to_lower(inode);
903 lower_dentry = ecryptfs_dentry_to_lower(dentry);
904 mutex_lock(&crypt_stat->cs_mutex);
905 if (d_is_dir(dentry))
906 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
907 else if (d_is_reg(dentry)
908 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
909 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
910 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
911
912 mount_crypt_stat = &ecryptfs_superblock_to_private(
913 dentry->d_sb)->mount_crypt_stat;
914 rc = ecryptfs_get_lower_file(dentry, inode);
915 if (rc) {
916 mutex_unlock(&crypt_stat->cs_mutex);
917 goto out;
918 }
919 rc = ecryptfs_read_metadata(dentry);
920 ecryptfs_put_lower_file(inode);
921 if (rc) {
922 if (!(mount_crypt_stat->flags
923 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
924 rc = -EIO;
925 printk(KERN_WARNING "Either the lower file "
926 "is not in a valid eCryptfs format, "
927 "or the key could not be retrieved. "
928 "Plaintext passthrough mode is not "
929 "enabled; returning -EIO\n");
930 mutex_unlock(&crypt_stat->cs_mutex);
931 goto out;
932 }
933 rc = 0;
934 crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
935 | ECRYPTFS_ENCRYPTED);
936 }
937 }
938 mutex_unlock(&crypt_stat->cs_mutex);
939
940 rc = setattr_prepare(&init_user_ns, dentry, ia);
941 if (rc)
942 goto out;
943 if (ia->ia_valid & ATTR_SIZE) {
944 rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size);
945 if (rc)
946 goto out;
947 }
948
949 memcpy(&lower_ia, ia, sizeof(lower_ia));
950 if (ia->ia_valid & ATTR_FILE)
951 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
952 if (ia->ia_valid & ATTR_SIZE) {
953 rc = truncate_upper(dentry, ia, &lower_ia);
954 if (rc < 0)
955 goto out;
956 }
957
958 /*
959 * mode change is for clearing setuid/setgid bits. Allow lower fs
960 * to interpret this in its own way.
961 */
962 if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
963 lower_ia.ia_valid &= ~ATTR_MODE;
964
965 inode_lock(d_inode(lower_dentry));
966 rc = notify_change(&init_user_ns, lower_dentry, &lower_ia, NULL);
967 inode_unlock(d_inode(lower_dentry));
968out:
969 fsstack_copy_attr_all(inode, lower_inode);
970 return rc;
971}
972
973static int ecryptfs_getattr_link(struct user_namespace *mnt_userns,
974 const struct path *path, struct kstat *stat,
975 u32 request_mask, unsigned int flags)
976{
977 struct dentry *dentry = path->dentry;
978 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
979 int rc = 0;
980
981 mount_crypt_stat = &ecryptfs_superblock_to_private(
982 dentry->d_sb)->mount_crypt_stat;
983 generic_fillattr(&init_user_ns, d_inode(dentry), stat);
984 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
985 char *target;
986 size_t targetsiz;
987
988 target = ecryptfs_readlink_lower(dentry, &targetsiz);
989 if (!IS_ERR(target)) {
990 kfree(target);
991 stat->size = targetsiz;
992 } else {
993 rc = PTR_ERR(target);
994 }
995 }
996 return rc;
997}
998
999static int ecryptfs_getattr(struct user_namespace *mnt_userns,
1000 const struct path *path, struct kstat *stat,
1001 u32 request_mask, unsigned int flags)
1002{
1003 struct dentry *dentry = path->dentry;
1004 struct kstat lower_stat;
1005 int rc;
1006
1007 rc = vfs_getattr(ecryptfs_dentry_to_lower_path(dentry), &lower_stat,
1008 request_mask, flags);
1009 if (!rc) {
1010 fsstack_copy_attr_all(d_inode(dentry),
1011 ecryptfs_inode_to_lower(d_inode(dentry)));
1012 generic_fillattr(&init_user_ns, d_inode(dentry), stat);
1013 stat->blocks = lower_stat.blocks;
1014 }
1015 return rc;
1016}
1017
1018int
1019ecryptfs_setxattr(struct dentry *dentry, struct inode *inode,
1020 const char *name, const void *value,
1021 size_t size, int flags)
1022{
1023 int rc;
1024 struct dentry *lower_dentry;
1025 struct inode *lower_inode;
1026
1027 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1028 lower_inode = d_inode(lower_dentry);
1029 if (!(lower_inode->i_opflags & IOP_XATTR)) {
1030 rc = -EOPNOTSUPP;
1031 goto out;
1032 }
1033 inode_lock(lower_inode);
1034 rc = __vfs_setxattr_locked(&init_user_ns, lower_dentry, name, value, size, flags, NULL);
1035 inode_unlock(lower_inode);
1036 if (!rc && inode)
1037 fsstack_copy_attr_all(inode, lower_inode);
1038out:
1039 return rc;
1040}
1041
1042ssize_t
1043ecryptfs_getxattr_lower(struct dentry *lower_dentry, struct inode *lower_inode,
1044 const char *name, void *value, size_t size)
1045{
1046 int rc;
1047
1048 if (!(lower_inode->i_opflags & IOP_XATTR)) {
1049 rc = -EOPNOTSUPP;
1050 goto out;
1051 }
1052 inode_lock(lower_inode);
1053 rc = __vfs_getxattr(lower_dentry, lower_inode, name, value, size);
1054 inode_unlock(lower_inode);
1055out:
1056 return rc;
1057}
1058
1059static ssize_t
1060ecryptfs_getxattr(struct dentry *dentry, struct inode *inode,
1061 const char *name, void *value, size_t size)
1062{
1063 return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
1064 ecryptfs_inode_to_lower(inode),
1065 name, value, size);
1066}
1067
1068static ssize_t
1069ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1070{
1071 int rc = 0;
1072 struct dentry *lower_dentry;
1073
1074 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1075 if (!d_inode(lower_dentry)->i_op->listxattr) {
1076 rc = -EOPNOTSUPP;
1077 goto out;
1078 }
1079 inode_lock(d_inode(lower_dentry));
1080 rc = d_inode(lower_dentry)->i_op->listxattr(lower_dentry, list, size);
1081 inode_unlock(d_inode(lower_dentry));
1082out:
1083 return rc;
1084}
1085
1086static int ecryptfs_removexattr(struct dentry *dentry, struct inode *inode,
1087 const char *name)
1088{
1089 int rc;
1090 struct dentry *lower_dentry;
1091 struct inode *lower_inode;
1092
1093 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1094 lower_inode = ecryptfs_inode_to_lower(inode);
1095 if (!(lower_inode->i_opflags & IOP_XATTR)) {
1096 rc = -EOPNOTSUPP;
1097 goto out;
1098 }
1099 inode_lock(lower_inode);
1100 rc = __vfs_removexattr(&init_user_ns, lower_dentry, name);
1101 inode_unlock(lower_inode);
1102out:
1103 return rc;
1104}
1105
1106static int ecryptfs_fileattr_get(struct dentry *dentry, struct fileattr *fa)
1107{
1108 return vfs_fileattr_get(ecryptfs_dentry_to_lower(dentry), fa);
1109}
1110
1111static int ecryptfs_fileattr_set(struct user_namespace *mnt_userns,
1112 struct dentry *dentry, struct fileattr *fa)
1113{
1114 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
1115 int rc;
1116
1117 rc = vfs_fileattr_set(&init_user_ns, lower_dentry, fa);
1118 fsstack_copy_attr_all(d_inode(dentry), d_inode(lower_dentry));
1119
1120 return rc;
1121}
1122
1123const struct inode_operations ecryptfs_symlink_iops = {
1124 .get_link = ecryptfs_get_link,
1125 .permission = ecryptfs_permission,
1126 .setattr = ecryptfs_setattr,
1127 .getattr = ecryptfs_getattr_link,
1128 .listxattr = ecryptfs_listxattr,
1129};
1130
1131const struct inode_operations ecryptfs_dir_iops = {
1132 .create = ecryptfs_create,
1133 .lookup = ecryptfs_lookup,
1134 .link = ecryptfs_link,
1135 .unlink = ecryptfs_unlink,
1136 .symlink = ecryptfs_symlink,
1137 .mkdir = ecryptfs_mkdir,
1138 .rmdir = ecryptfs_rmdir,
1139 .mknod = ecryptfs_mknod,
1140 .rename = ecryptfs_rename,
1141 .permission = ecryptfs_permission,
1142 .setattr = ecryptfs_setattr,
1143 .listxattr = ecryptfs_listxattr,
1144 .fileattr_get = ecryptfs_fileattr_get,
1145 .fileattr_set = ecryptfs_fileattr_set,
1146};
1147
1148const struct inode_operations ecryptfs_main_iops = {
1149 .permission = ecryptfs_permission,
1150 .setattr = ecryptfs_setattr,
1151 .getattr = ecryptfs_getattr,
1152 .listxattr = ecryptfs_listxattr,
1153 .fileattr_get = ecryptfs_fileattr_get,
1154 .fileattr_set = ecryptfs_fileattr_set,
1155};
1156
1157static int ecryptfs_xattr_get(const struct xattr_handler *handler,
1158 struct dentry *dentry, struct inode *inode,
1159 const char *name, void *buffer, size_t size)
1160{
1161 return ecryptfs_getxattr(dentry, inode, name, buffer, size);
1162}
1163
1164static int ecryptfs_xattr_set(const struct xattr_handler *handler,
1165 struct user_namespace *mnt_userns,
1166 struct dentry *dentry, struct inode *inode,
1167 const char *name, const void *value, size_t size,
1168 int flags)
1169{
1170 if (value)
1171 return ecryptfs_setxattr(dentry, inode, name, value, size, flags);
1172 else {
1173 BUG_ON(flags != XATTR_REPLACE);
1174 return ecryptfs_removexattr(dentry, inode, name);
1175 }
1176}
1177
1178static const struct xattr_handler ecryptfs_xattr_handler = {
1179 .prefix = "", /* match anything */
1180 .get = ecryptfs_xattr_get,
1181 .set = ecryptfs_xattr_set,
1182};
1183
1184const struct xattr_handler *ecryptfs_xattr_handlers[] = {
1185 &ecryptfs_xattr_handler,
1186 NULL
1187};