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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};
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/posix_acl.h>
22#include <linux/posix_acl_xattr.h>
23#include <linux/fileattr.h>
24#include <linux/unaligned.h>
25#include "ecryptfs_kernel.h"
26
27static int lock_parent(struct dentry *dentry,
28 struct dentry **lower_dentry,
29 struct inode **lower_dir)
30{
31 struct dentry *lower_dir_dentry;
32
33 lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
34 *lower_dir = d_inode(lower_dir_dentry);
35 *lower_dentry = ecryptfs_dentry_to_lower(dentry);
36
37 inode_lock_nested(*lower_dir, I_MUTEX_PARENT);
38 return (*lower_dentry)->d_parent == lower_dir_dentry ? 0 : -EINVAL;
39}
40
41static int ecryptfs_inode_test(struct inode *inode, void *lower_inode)
42{
43 return ecryptfs_inode_to_lower(inode) == lower_inode;
44}
45
46static int ecryptfs_inode_set(struct inode *inode, void *opaque)
47{
48 struct inode *lower_inode = opaque;
49
50 ecryptfs_set_inode_lower(inode, lower_inode);
51 fsstack_copy_attr_all(inode, lower_inode);
52 /* i_size will be overwritten for encrypted regular files */
53 fsstack_copy_inode_size(inode, lower_inode);
54 inode->i_ino = lower_inode->i_ino;
55 inode->i_mapping->a_ops = &ecryptfs_aops;
56
57 if (S_ISLNK(inode->i_mode))
58 inode->i_op = &ecryptfs_symlink_iops;
59 else if (S_ISDIR(inode->i_mode))
60 inode->i_op = &ecryptfs_dir_iops;
61 else
62 inode->i_op = &ecryptfs_main_iops;
63
64 if (S_ISDIR(inode->i_mode))
65 inode->i_fop = &ecryptfs_dir_fops;
66 else if (special_file(inode->i_mode))
67 init_special_inode(inode, inode->i_mode, inode->i_rdev);
68 else
69 inode->i_fop = &ecryptfs_main_fops;
70
71 return 0;
72}
73
74static struct inode *__ecryptfs_get_inode(struct inode *lower_inode,
75 struct super_block *sb)
76{
77 struct inode *inode;
78
79 if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb))
80 return ERR_PTR(-EXDEV);
81
82 /* Reject dealing with casefold directories. */
83 if (IS_CASEFOLDED(lower_inode)) {
84 pr_err_ratelimited("%s: Can't handle casefolded directory.\n",
85 __func__);
86 return ERR_PTR(-EREMOTE);
87 }
88
89 if (!igrab(lower_inode))
90 return ERR_PTR(-ESTALE);
91 inode = iget5_locked(sb, (unsigned long)lower_inode,
92 ecryptfs_inode_test, ecryptfs_inode_set,
93 lower_inode);
94 if (!inode) {
95 iput(lower_inode);
96 return ERR_PTR(-EACCES);
97 }
98 if (!(inode->i_state & I_NEW))
99 iput(lower_inode);
100
101 return inode;
102}
103
104struct inode *ecryptfs_get_inode(struct inode *lower_inode,
105 struct super_block *sb)
106{
107 struct inode *inode = __ecryptfs_get_inode(lower_inode, sb);
108
109 if (!IS_ERR(inode) && (inode->i_state & I_NEW))
110 unlock_new_inode(inode);
111
112 return inode;
113}
114
115/**
116 * ecryptfs_interpose
117 * @lower_dentry: Existing dentry in the lower filesystem
118 * @dentry: ecryptfs' dentry
119 * @sb: ecryptfs's super_block
120 *
121 * Interposes upper and lower dentries.
122 *
123 * Returns zero on success; non-zero otherwise
124 */
125static int ecryptfs_interpose(struct dentry *lower_dentry,
126 struct dentry *dentry, struct super_block *sb)
127{
128 struct inode *inode = ecryptfs_get_inode(d_inode(lower_dentry), sb);
129
130 if (IS_ERR(inode))
131 return PTR_ERR(inode);
132 d_instantiate(dentry, inode);
133
134 return 0;
135}
136
137static int ecryptfs_do_unlink(struct inode *dir, struct dentry *dentry,
138 struct inode *inode)
139{
140 struct dentry *lower_dentry;
141 struct inode *lower_dir;
142 int rc;
143
144 rc = lock_parent(dentry, &lower_dentry, &lower_dir);
145 dget(lower_dentry); // don't even try to make the lower negative
146 if (!rc) {
147 if (d_unhashed(lower_dentry))
148 rc = -EINVAL;
149 else
150 rc = vfs_unlink(&nop_mnt_idmap, lower_dir, lower_dentry,
151 NULL);
152 }
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);
158 set_nlink(inode, ecryptfs_inode_to_lower(inode)->i_nlink);
159 inode_set_ctime_to_ts(inode, inode_get_ctime(dir));
160out_unlock:
161 dput(lower_dentry);
162 inode_unlock(lower_dir);
163 if (!rc)
164 d_drop(dentry);
165 return rc;
166}
167
168/**
169 * ecryptfs_do_create
170 * @directory_inode: inode of the new file's dentry's parent in ecryptfs
171 * @ecryptfs_dentry: New file's dentry in ecryptfs
172 * @mode: The mode of the new file
173 *
174 * Creates the underlying file and the eCryptfs inode which will link to
175 * it. It will also update the eCryptfs directory inode to mimic the
176 * stat of the lower directory inode.
177 *
178 * Returns the new eCryptfs inode on success; an ERR_PTR on error condition
179 */
180static struct inode *
181ecryptfs_do_create(struct inode *directory_inode,
182 struct dentry *ecryptfs_dentry, umode_t mode)
183{
184 int rc;
185 struct dentry *lower_dentry;
186 struct inode *lower_dir;
187 struct inode *inode;
188
189 rc = lock_parent(ecryptfs_dentry, &lower_dentry, &lower_dir);
190 if (!rc)
191 rc = vfs_create(&nop_mnt_idmap, lower_dir,
192 lower_dentry, mode, true);
193 if (rc) {
194 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
195 "rc = [%d]\n", __func__, rc);
196 inode = ERR_PTR(rc);
197 goto out_lock;
198 }
199 inode = __ecryptfs_get_inode(d_inode(lower_dentry),
200 directory_inode->i_sb);
201 if (IS_ERR(inode)) {
202 vfs_unlink(&nop_mnt_idmap, lower_dir, lower_dentry, NULL);
203 goto out_lock;
204 }
205 fsstack_copy_attr_times(directory_inode, lower_dir);
206 fsstack_copy_inode_size(directory_inode, lower_dir);
207out_lock:
208 inode_unlock(lower_dir);
209 return inode;
210}
211
212/*
213 * ecryptfs_initialize_file
214 *
215 * Cause the file to be changed from a basic empty file to an ecryptfs
216 * file with a header and first data page.
217 *
218 * Returns zero on success
219 */
220int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry,
221 struct inode *ecryptfs_inode)
222{
223 struct ecryptfs_crypt_stat *crypt_stat =
224 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
225 int rc = 0;
226
227 if (S_ISDIR(ecryptfs_inode->i_mode)) {
228 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
229 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
230 goto out;
231 }
232 ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
233 rc = ecryptfs_new_file_context(ecryptfs_inode);
234 if (rc) {
235 ecryptfs_printk(KERN_ERR, "Error creating new file "
236 "context; rc = [%d]\n", rc);
237 goto out;
238 }
239 rc = ecryptfs_get_lower_file(ecryptfs_dentry, ecryptfs_inode);
240 if (rc) {
241 printk(KERN_ERR "%s: Error attempting to initialize "
242 "the lower file for the dentry with name "
243 "[%pd]; rc = [%d]\n", __func__,
244 ecryptfs_dentry, rc);
245 goto out;
246 }
247 rc = ecryptfs_write_metadata(ecryptfs_dentry, ecryptfs_inode);
248 if (rc)
249 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
250 ecryptfs_put_lower_file(ecryptfs_inode);
251out:
252 return rc;
253}
254
255/*
256 * ecryptfs_create
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 mnt_idmap *idmap,
265 struct inode *directory_inode, struct dentry *ecryptfs_dentry,
266 umode_t mode, bool excl)
267{
268 struct inode *ecryptfs_inode;
269 int rc;
270
271 ecryptfs_inode = ecryptfs_do_create(directory_inode, ecryptfs_dentry,
272 mode);
273 if (IS_ERR(ecryptfs_inode)) {
274 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
275 "lower filesystem\n");
276 rc = PTR_ERR(ecryptfs_inode);
277 goto out;
278 }
279 /* At this point, a file exists on "disk"; we need to make sure
280 * that this on disk file is prepared to be an ecryptfs file */
281 rc = ecryptfs_initialize_file(ecryptfs_dentry, ecryptfs_inode);
282 if (rc) {
283 ecryptfs_do_unlink(directory_inode, ecryptfs_dentry,
284 ecryptfs_inode);
285 iget_failed(ecryptfs_inode);
286 goto out;
287 }
288 d_instantiate_new(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 const struct path *path = ecryptfs_dentry_to_lower_path(dentry->d_parent);
331 struct inode *inode, *lower_inode;
332 struct ecryptfs_dentry_info *dentry_info;
333 int rc = 0;
334
335 dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
336 if (!dentry_info) {
337 dput(lower_dentry);
338 return ERR_PTR(-ENOMEM);
339 }
340
341 fsstack_copy_attr_atime(d_inode(dentry->d_parent),
342 d_inode(path->dentry));
343 BUG_ON(!d_count(lower_dentry));
344
345 ecryptfs_set_dentry_private(dentry, dentry_info);
346 dentry_info->lower_path.mnt = mntget(path->mnt);
347 dentry_info->lower_path.dentry = lower_dentry;
348
349 /*
350 * negative dentry can go positive under us here - its parent is not
351 * locked. That's OK and that could happen just as we return from
352 * ecryptfs_lookup() anyway. Just need to be careful and fetch
353 * ->d_inode only once - it's not stable here.
354 */
355 lower_inode = READ_ONCE(lower_dentry->d_inode);
356
357 if (!lower_inode) {
358 /* We want to add because we couldn't find in lower */
359 d_add(dentry, NULL);
360 return NULL;
361 }
362 inode = __ecryptfs_get_inode(lower_inode, dentry->d_sb);
363 if (IS_ERR(inode)) {
364 printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
365 __func__, PTR_ERR(inode));
366 return ERR_CAST(inode);
367 }
368 if (S_ISREG(inode->i_mode)) {
369 rc = ecryptfs_i_size_read(dentry, inode);
370 if (rc) {
371 make_bad_inode(inode);
372 return ERR_PTR(rc);
373 }
374 }
375
376 if (inode->i_state & I_NEW)
377 unlock_new_inode(inode);
378 return d_splice_alias(inode, dentry);
379}
380
381/**
382 * ecryptfs_lookup
383 * @ecryptfs_dir_inode: The eCryptfs directory inode
384 * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
385 * @flags: lookup flags
386 *
387 * Find a file on disk. If the file does not exist, then we'll add it to the
388 * dentry cache and continue on to read it from the disk.
389 */
390static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
391 struct dentry *ecryptfs_dentry,
392 unsigned int flags)
393{
394 char *encrypted_and_encoded_name = NULL;
395 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
396 struct dentry *lower_dir_dentry, *lower_dentry;
397 const char *name = ecryptfs_dentry->d_name.name;
398 size_t len = ecryptfs_dentry->d_name.len;
399 struct dentry *res;
400 int rc = 0;
401
402 lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
403
404 mount_crypt_stat = &ecryptfs_superblock_to_private(
405 ecryptfs_dentry->d_sb)->mount_crypt_stat;
406 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
407 rc = ecryptfs_encrypt_and_encode_filename(
408 &encrypted_and_encoded_name, &len,
409 mount_crypt_stat, name, len);
410 if (rc) {
411 printk(KERN_ERR "%s: Error attempting to encrypt and encode "
412 "filename; rc = [%d]\n", __func__, rc);
413 return ERR_PTR(rc);
414 }
415 name = encrypted_and_encoded_name;
416 }
417
418 lower_dentry = lookup_one_len_unlocked(name, lower_dir_dentry, len);
419 if (IS_ERR(lower_dentry)) {
420 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
421 "[%ld] on lower_dentry = [%s]\n", __func__,
422 PTR_ERR(lower_dentry),
423 name);
424 res = ERR_CAST(lower_dentry);
425 } else {
426 res = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry);
427 }
428 kfree(encrypted_and_encoded_name);
429 return res;
430}
431
432static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
433 struct dentry *new_dentry)
434{
435 struct dentry *lower_old_dentry;
436 struct dentry *lower_new_dentry;
437 struct inode *lower_dir;
438 u64 file_size_save;
439 int rc;
440
441 file_size_save = i_size_read(d_inode(old_dentry));
442 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
443 rc = lock_parent(new_dentry, &lower_new_dentry, &lower_dir);
444 if (!rc)
445 rc = vfs_link(lower_old_dentry, &nop_mnt_idmap, lower_dir,
446 lower_new_dentry, NULL);
447 if (rc || d_really_is_negative(lower_new_dentry))
448 goto out_lock;
449 rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
450 if (rc)
451 goto out_lock;
452 fsstack_copy_attr_times(dir, lower_dir);
453 fsstack_copy_inode_size(dir, lower_dir);
454 set_nlink(d_inode(old_dentry),
455 ecryptfs_inode_to_lower(d_inode(old_dentry))->i_nlink);
456 i_size_write(d_inode(new_dentry), file_size_save);
457out_lock:
458 inode_unlock(lower_dir);
459 return rc;
460}
461
462static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
463{
464 return ecryptfs_do_unlink(dir, dentry, d_inode(dentry));
465}
466
467static int ecryptfs_symlink(struct mnt_idmap *idmap,
468 struct inode *dir, struct dentry *dentry,
469 const char *symname)
470{
471 int rc;
472 struct dentry *lower_dentry;
473 struct inode *lower_dir;
474 char *encoded_symname;
475 size_t encoded_symlen;
476 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
477
478 rc = lock_parent(dentry, &lower_dentry, &lower_dir);
479 if (rc)
480 goto out_lock;
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(&nop_mnt_idmap, lower_dir, 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, lower_dir);
498 fsstack_copy_inode_size(dir, lower_dir);
499out_lock:
500 inode_unlock(lower_dir);
501 if (d_really_is_negative(dentry))
502 d_drop(dentry);
503 return rc;
504}
505
506static int ecryptfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
507 struct dentry *dentry, umode_t mode)
508{
509 int rc;
510 struct dentry *lower_dentry;
511 struct inode *lower_dir;
512
513 rc = lock_parent(dentry, &lower_dentry, &lower_dir);
514 if (!rc)
515 rc = vfs_mkdir(&nop_mnt_idmap, lower_dir,
516 lower_dentry, mode);
517 if (rc || d_really_is_negative(lower_dentry))
518 goto out;
519 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
520 if (rc)
521 goto out;
522 fsstack_copy_attr_times(dir, lower_dir);
523 fsstack_copy_inode_size(dir, lower_dir);
524 set_nlink(dir, lower_dir->i_nlink);
525out:
526 inode_unlock(lower_dir);
527 if (d_really_is_negative(dentry))
528 d_drop(dentry);
529 return rc;
530}
531
532static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
533{
534 struct dentry *lower_dentry;
535 struct inode *lower_dir;
536 int rc;
537
538 rc = lock_parent(dentry, &lower_dentry, &lower_dir);
539 dget(lower_dentry); // don't even try to make the lower negative
540 if (!rc) {
541 if (d_unhashed(lower_dentry))
542 rc = -EINVAL;
543 else
544 rc = vfs_rmdir(&nop_mnt_idmap, lower_dir, lower_dentry);
545 }
546 if (!rc) {
547 clear_nlink(d_inode(dentry));
548 fsstack_copy_attr_times(dir, lower_dir);
549 set_nlink(dir, lower_dir->i_nlink);
550 }
551 dput(lower_dentry);
552 inode_unlock(lower_dir);
553 if (!rc)
554 d_drop(dentry);
555 return rc;
556}
557
558static int
559ecryptfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
560 struct dentry *dentry, umode_t mode, dev_t dev)
561{
562 int rc;
563 struct dentry *lower_dentry;
564 struct inode *lower_dir;
565
566 rc = lock_parent(dentry, &lower_dentry, &lower_dir);
567 if (!rc)
568 rc = vfs_mknod(&nop_mnt_idmap, lower_dir,
569 lower_dentry, mode, dev);
570 if (rc || d_really_is_negative(lower_dentry))
571 goto out;
572 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
573 if (rc)
574 goto out;
575 fsstack_copy_attr_times(dir, lower_dir);
576 fsstack_copy_inode_size(dir, lower_dir);
577out:
578 inode_unlock(lower_dir);
579 if (d_really_is_negative(dentry))
580 d_drop(dentry);
581 return rc;
582}
583
584static int
585ecryptfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
586 struct dentry *old_dentry, struct inode *new_dir,
587 struct dentry *new_dentry, unsigned int flags)
588{
589 int rc;
590 struct dentry *lower_old_dentry;
591 struct dentry *lower_new_dentry;
592 struct dentry *lower_old_dir_dentry;
593 struct dentry *lower_new_dir_dentry;
594 struct dentry *trap;
595 struct inode *target_inode;
596 struct renamedata rd = {};
597
598 if (flags)
599 return -EINVAL;
600
601 lower_old_dir_dentry = ecryptfs_dentry_to_lower(old_dentry->d_parent);
602 lower_new_dir_dentry = ecryptfs_dentry_to_lower(new_dentry->d_parent);
603
604 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
605 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
606
607 target_inode = d_inode(new_dentry);
608
609 trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
610 if (IS_ERR(trap))
611 return PTR_ERR(trap);
612 dget(lower_new_dentry);
613 rc = -EINVAL;
614 if (lower_old_dentry->d_parent != lower_old_dir_dentry)
615 goto out_lock;
616 if (lower_new_dentry->d_parent != lower_new_dir_dentry)
617 goto out_lock;
618 if (d_unhashed(lower_old_dentry) || d_unhashed(lower_new_dentry))
619 goto out_lock;
620 /* source should not be ancestor of target */
621 if (trap == lower_old_dentry)
622 goto out_lock;
623 /* target should not be ancestor of source */
624 if (trap == lower_new_dentry) {
625 rc = -ENOTEMPTY;
626 goto out_lock;
627 }
628
629 rd.old_mnt_idmap = &nop_mnt_idmap;
630 rd.old_dir = d_inode(lower_old_dir_dentry);
631 rd.old_dentry = lower_old_dentry;
632 rd.new_mnt_idmap = &nop_mnt_idmap;
633 rd.new_dir = d_inode(lower_new_dir_dentry);
634 rd.new_dentry = lower_new_dentry;
635 rc = vfs_rename(&rd);
636 if (rc)
637 goto out_lock;
638 if (target_inode)
639 fsstack_copy_attr_all(target_inode,
640 ecryptfs_inode_to_lower(target_inode));
641 fsstack_copy_attr_all(new_dir, d_inode(lower_new_dir_dentry));
642 if (new_dir != old_dir)
643 fsstack_copy_attr_all(old_dir, d_inode(lower_old_dir_dentry));
644out_lock:
645 dput(lower_new_dentry);
646 unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
647 return rc;
648}
649
650static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
651{
652 DEFINE_DELAYED_CALL(done);
653 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
654 const char *link;
655 char *buf;
656 int rc;
657
658 link = vfs_get_link(lower_dentry, &done);
659 if (IS_ERR(link))
660 return ERR_CAST(link);
661
662 rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb,
663 link, strlen(link));
664 do_delayed_call(&done);
665 if (rc)
666 return ERR_PTR(rc);
667
668 return buf;
669}
670
671static const char *ecryptfs_get_link(struct dentry *dentry,
672 struct inode *inode,
673 struct delayed_call *done)
674{
675 size_t len;
676 char *buf;
677
678 if (!dentry)
679 return ERR_PTR(-ECHILD);
680
681 buf = ecryptfs_readlink_lower(dentry, &len);
682 if (IS_ERR(buf))
683 return buf;
684 fsstack_copy_attr_atime(d_inode(dentry),
685 d_inode(ecryptfs_dentry_to_lower(dentry)));
686 buf[len] = '\0';
687 set_delayed_call(done, kfree_link, buf);
688 return buf;
689}
690
691/**
692 * upper_size_to_lower_size
693 * @crypt_stat: Crypt_stat associated with file
694 * @upper_size: Size of the upper file
695 *
696 * Calculate the required size of the lower file based on the
697 * specified size of the upper file. This calculation is based on the
698 * number of headers in the underlying file and the extent size.
699 *
700 * Returns Calculated size of the lower file.
701 */
702static loff_t
703upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
704 loff_t upper_size)
705{
706 loff_t lower_size;
707
708 lower_size = ecryptfs_lower_header_size(crypt_stat);
709 if (upper_size != 0) {
710 loff_t num_extents;
711
712 num_extents = upper_size >> crypt_stat->extent_shift;
713 if (upper_size & ~crypt_stat->extent_mask)
714 num_extents++;
715 lower_size += (num_extents * crypt_stat->extent_size);
716 }
717 return lower_size;
718}
719
720/**
721 * truncate_upper
722 * @dentry: The ecryptfs layer dentry
723 * @ia: Address of the ecryptfs inode's attributes
724 * @lower_ia: Address of the lower inode's attributes
725 *
726 * Function to handle truncations modifying the size of the file. Note
727 * that the file sizes are interpolated. When expanding, we are simply
728 * writing strings of 0's out. When truncating, we truncate the upper
729 * inode and update the lower_ia according to the page index
730 * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
731 * the caller must use lower_ia in a call to notify_change() to perform
732 * the truncation of the lower inode.
733 *
734 * Returns zero on success; non-zero otherwise
735 */
736static int truncate_upper(struct dentry *dentry, struct iattr *ia,
737 struct iattr *lower_ia)
738{
739 int rc = 0;
740 struct inode *inode = d_inode(dentry);
741 struct ecryptfs_crypt_stat *crypt_stat;
742 loff_t i_size = i_size_read(inode);
743 loff_t lower_size_before_truncate;
744 loff_t lower_size_after_truncate;
745
746 if (unlikely((ia->ia_size == i_size))) {
747 lower_ia->ia_valid &= ~ATTR_SIZE;
748 return 0;
749 }
750 rc = ecryptfs_get_lower_file(dentry, inode);
751 if (rc)
752 return rc;
753 crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
754 /* Switch on growing or shrinking file */
755 if (ia->ia_size > i_size) {
756 char zero[] = { 0x00 };
757
758 lower_ia->ia_valid &= ~ATTR_SIZE;
759 /* Write a single 0 at the last position of the file;
760 * this triggers code that will fill in 0's throughout
761 * the intermediate portion of the previous end of the
762 * file and the new and of the file */
763 rc = ecryptfs_write(inode, zero,
764 (ia->ia_size - 1), 1);
765 } else { /* ia->ia_size < i_size_read(inode) */
766 /* We're chopping off all the pages down to the page
767 * in which ia->ia_size is located. Fill in the end of
768 * that page from (ia->ia_size & ~PAGE_MASK) to
769 * PAGE_SIZE with zeros. */
770 size_t num_zeros = (PAGE_SIZE
771 - (ia->ia_size & ~PAGE_MASK));
772
773 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
774 truncate_setsize(inode, ia->ia_size);
775 lower_ia->ia_size = ia->ia_size;
776 lower_ia->ia_valid |= ATTR_SIZE;
777 goto out;
778 }
779 if (num_zeros) {
780 char *zeros_virt;
781
782 zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
783 if (!zeros_virt) {
784 rc = -ENOMEM;
785 goto out;
786 }
787 rc = ecryptfs_write(inode, zeros_virt,
788 ia->ia_size, num_zeros);
789 kfree(zeros_virt);
790 if (rc) {
791 printk(KERN_ERR "Error attempting to zero out "
792 "the remainder of the end page on "
793 "reducing truncate; rc = [%d]\n", rc);
794 goto out;
795 }
796 }
797 truncate_setsize(inode, ia->ia_size);
798 rc = ecryptfs_write_inode_size_to_metadata(inode);
799 if (rc) {
800 printk(KERN_ERR "Problem with "
801 "ecryptfs_write_inode_size_to_metadata; "
802 "rc = [%d]\n", rc);
803 goto out;
804 }
805 /* We are reducing the size of the ecryptfs file, and need to
806 * know if we need to reduce the size of the lower file. */
807 lower_size_before_truncate =
808 upper_size_to_lower_size(crypt_stat, i_size);
809 lower_size_after_truncate =
810 upper_size_to_lower_size(crypt_stat, ia->ia_size);
811 if (lower_size_after_truncate < lower_size_before_truncate) {
812 lower_ia->ia_size = lower_size_after_truncate;
813 lower_ia->ia_valid |= ATTR_SIZE;
814 } else
815 lower_ia->ia_valid &= ~ATTR_SIZE;
816 }
817out:
818 ecryptfs_put_lower_file(inode);
819 return rc;
820}
821
822static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset)
823{
824 struct ecryptfs_crypt_stat *crypt_stat;
825 loff_t lower_oldsize, lower_newsize;
826
827 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
828 lower_oldsize = upper_size_to_lower_size(crypt_stat,
829 i_size_read(inode));
830 lower_newsize = upper_size_to_lower_size(crypt_stat, offset);
831 if (lower_newsize > lower_oldsize) {
832 /*
833 * The eCryptfs inode and the new *lower* size are mixed here
834 * because we may not have the lower i_mutex held and/or it may
835 * not be appropriate to call inode_newsize_ok() with inodes
836 * from other filesystems.
837 */
838 return inode_newsize_ok(inode, lower_newsize);
839 }
840
841 return 0;
842}
843
844/**
845 * ecryptfs_truncate
846 * @dentry: The ecryptfs layer dentry
847 * @new_length: The length to expand the file to
848 *
849 * Simple function that handles the truncation of an eCryptfs inode and
850 * its corresponding lower inode.
851 *
852 * Returns zero on success; non-zero otherwise
853 */
854int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
855{
856 struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
857 struct iattr lower_ia = { .ia_valid = 0 };
858 int rc;
859
860 rc = ecryptfs_inode_newsize_ok(d_inode(dentry), new_length);
861 if (rc)
862 return rc;
863
864 rc = truncate_upper(dentry, &ia, &lower_ia);
865 if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
866 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
867
868 inode_lock(d_inode(lower_dentry));
869 rc = notify_change(&nop_mnt_idmap, lower_dentry,
870 &lower_ia, NULL);
871 inode_unlock(d_inode(lower_dentry));
872 }
873 return rc;
874}
875
876static int
877ecryptfs_permission(struct mnt_idmap *idmap, struct inode *inode,
878 int mask)
879{
880 return inode_permission(&nop_mnt_idmap,
881 ecryptfs_inode_to_lower(inode), mask);
882}
883
884/**
885 * ecryptfs_setattr
886 * @idmap: idmap of the target mount
887 * @dentry: dentry handle to the inode to modify
888 * @ia: Structure with flags of what to change and values
889 *
890 * Updates the metadata of an inode. If the update is to the size
891 * i.e. truncation, then ecryptfs_truncate will handle the size modification
892 * of both the ecryptfs inode and the lower inode.
893 *
894 * All other metadata changes will be passed right to the lower filesystem,
895 * and we will just update our inode to look like the lower.
896 */
897static int ecryptfs_setattr(struct mnt_idmap *idmap,
898 struct dentry *dentry, struct iattr *ia)
899{
900 int rc = 0;
901 struct dentry *lower_dentry;
902 struct iattr lower_ia;
903 struct inode *inode;
904 struct inode *lower_inode;
905 struct ecryptfs_crypt_stat *crypt_stat;
906
907 crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
908 if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)) {
909 rc = ecryptfs_init_crypt_stat(crypt_stat);
910 if (rc)
911 return rc;
912 }
913 inode = d_inode(dentry);
914 lower_inode = ecryptfs_inode_to_lower(inode);
915 lower_dentry = ecryptfs_dentry_to_lower(dentry);
916 mutex_lock(&crypt_stat->cs_mutex);
917 if (d_is_dir(dentry))
918 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
919 else if (d_is_reg(dentry)
920 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
921 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
922 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
923
924 mount_crypt_stat = &ecryptfs_superblock_to_private(
925 dentry->d_sb)->mount_crypt_stat;
926 rc = ecryptfs_get_lower_file(dentry, inode);
927 if (rc) {
928 mutex_unlock(&crypt_stat->cs_mutex);
929 goto out;
930 }
931 rc = ecryptfs_read_metadata(dentry);
932 ecryptfs_put_lower_file(inode);
933 if (rc) {
934 if (!(mount_crypt_stat->flags
935 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
936 rc = -EIO;
937 printk(KERN_WARNING "Either the lower file "
938 "is not in a valid eCryptfs format, "
939 "or the key could not be retrieved. "
940 "Plaintext passthrough mode is not "
941 "enabled; returning -EIO\n");
942 mutex_unlock(&crypt_stat->cs_mutex);
943 goto out;
944 }
945 rc = 0;
946 crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
947 | ECRYPTFS_ENCRYPTED);
948 }
949 }
950 mutex_unlock(&crypt_stat->cs_mutex);
951
952 rc = setattr_prepare(&nop_mnt_idmap, dentry, ia);
953 if (rc)
954 goto out;
955 if (ia->ia_valid & ATTR_SIZE) {
956 rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size);
957 if (rc)
958 goto out;
959 }
960
961 memcpy(&lower_ia, ia, sizeof(lower_ia));
962 if (ia->ia_valid & ATTR_FILE)
963 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
964 if (ia->ia_valid & ATTR_SIZE) {
965 rc = truncate_upper(dentry, ia, &lower_ia);
966 if (rc < 0)
967 goto out;
968 }
969
970 /*
971 * mode change is for clearing setuid/setgid bits. Allow lower fs
972 * to interpret this in its own way.
973 */
974 if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
975 lower_ia.ia_valid &= ~ATTR_MODE;
976
977 inode_lock(d_inode(lower_dentry));
978 rc = notify_change(&nop_mnt_idmap, lower_dentry, &lower_ia, NULL);
979 inode_unlock(d_inode(lower_dentry));
980out:
981 fsstack_copy_attr_all(inode, lower_inode);
982 return rc;
983}
984
985static int ecryptfs_getattr_link(struct mnt_idmap *idmap,
986 const struct path *path, struct kstat *stat,
987 u32 request_mask, unsigned int flags)
988{
989 struct dentry *dentry = path->dentry;
990 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
991 int rc = 0;
992
993 mount_crypt_stat = &ecryptfs_superblock_to_private(
994 dentry->d_sb)->mount_crypt_stat;
995 generic_fillattr(&nop_mnt_idmap, request_mask, d_inode(dentry), stat);
996 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
997 char *target;
998 size_t targetsiz;
999
1000 target = ecryptfs_readlink_lower(dentry, &targetsiz);
1001 if (!IS_ERR(target)) {
1002 kfree(target);
1003 stat->size = targetsiz;
1004 } else {
1005 rc = PTR_ERR(target);
1006 }
1007 }
1008 return rc;
1009}
1010
1011static int ecryptfs_getattr(struct mnt_idmap *idmap,
1012 const struct path *path, struct kstat *stat,
1013 u32 request_mask, unsigned int flags)
1014{
1015 struct dentry *dentry = path->dentry;
1016 struct kstat lower_stat;
1017 int rc;
1018
1019 rc = vfs_getattr_nosec(ecryptfs_dentry_to_lower_path(dentry),
1020 &lower_stat, request_mask, flags);
1021 if (!rc) {
1022 fsstack_copy_attr_all(d_inode(dentry),
1023 ecryptfs_inode_to_lower(d_inode(dentry)));
1024 generic_fillattr(&nop_mnt_idmap, request_mask,
1025 d_inode(dentry), stat);
1026 stat->blocks = lower_stat.blocks;
1027 }
1028 return rc;
1029}
1030
1031int
1032ecryptfs_setxattr(struct dentry *dentry, struct inode *inode,
1033 const char *name, const void *value,
1034 size_t size, int flags)
1035{
1036 int rc;
1037 struct dentry *lower_dentry;
1038 struct inode *lower_inode;
1039
1040 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1041 lower_inode = d_inode(lower_dentry);
1042 if (!(lower_inode->i_opflags & IOP_XATTR)) {
1043 rc = -EOPNOTSUPP;
1044 goto out;
1045 }
1046 inode_lock(lower_inode);
1047 rc = __vfs_setxattr_locked(&nop_mnt_idmap, lower_dentry, name, value, size, flags, NULL);
1048 inode_unlock(lower_inode);
1049 if (!rc && inode)
1050 fsstack_copy_attr_all(inode, lower_inode);
1051out:
1052 return rc;
1053}
1054
1055ssize_t
1056ecryptfs_getxattr_lower(struct dentry *lower_dentry, struct inode *lower_inode,
1057 const char *name, void *value, size_t size)
1058{
1059 int rc;
1060
1061 if (!(lower_inode->i_opflags & IOP_XATTR)) {
1062 rc = -EOPNOTSUPP;
1063 goto out;
1064 }
1065 inode_lock(lower_inode);
1066 rc = __vfs_getxattr(lower_dentry, lower_inode, name, value, size);
1067 inode_unlock(lower_inode);
1068out:
1069 return rc;
1070}
1071
1072static ssize_t
1073ecryptfs_getxattr(struct dentry *dentry, struct inode *inode,
1074 const char *name, void *value, size_t size)
1075{
1076 return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
1077 ecryptfs_inode_to_lower(inode),
1078 name, value, size);
1079}
1080
1081static ssize_t
1082ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1083{
1084 int rc = 0;
1085 struct dentry *lower_dentry;
1086
1087 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1088 if (!d_inode(lower_dentry)->i_op->listxattr) {
1089 rc = -EOPNOTSUPP;
1090 goto out;
1091 }
1092 inode_lock(d_inode(lower_dentry));
1093 rc = d_inode(lower_dentry)->i_op->listxattr(lower_dentry, list, size);
1094 inode_unlock(d_inode(lower_dentry));
1095out:
1096 return rc;
1097}
1098
1099static int ecryptfs_removexattr(struct dentry *dentry, struct inode *inode,
1100 const char *name)
1101{
1102 int rc;
1103 struct dentry *lower_dentry;
1104 struct inode *lower_inode;
1105
1106 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1107 lower_inode = ecryptfs_inode_to_lower(inode);
1108 if (!(lower_inode->i_opflags & IOP_XATTR)) {
1109 rc = -EOPNOTSUPP;
1110 goto out;
1111 }
1112 inode_lock(lower_inode);
1113 rc = __vfs_removexattr(&nop_mnt_idmap, lower_dentry, name);
1114 inode_unlock(lower_inode);
1115out:
1116 return rc;
1117}
1118
1119static int ecryptfs_fileattr_get(struct dentry *dentry, struct fileattr *fa)
1120{
1121 return vfs_fileattr_get(ecryptfs_dentry_to_lower(dentry), fa);
1122}
1123
1124static int ecryptfs_fileattr_set(struct mnt_idmap *idmap,
1125 struct dentry *dentry, struct fileattr *fa)
1126{
1127 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
1128 int rc;
1129
1130 rc = vfs_fileattr_set(&nop_mnt_idmap, lower_dentry, fa);
1131 fsstack_copy_attr_all(d_inode(dentry), d_inode(lower_dentry));
1132
1133 return rc;
1134}
1135
1136static struct posix_acl *ecryptfs_get_acl(struct mnt_idmap *idmap,
1137 struct dentry *dentry, int type)
1138{
1139 return vfs_get_acl(idmap, ecryptfs_dentry_to_lower(dentry),
1140 posix_acl_xattr_name(type));
1141}
1142
1143static int ecryptfs_set_acl(struct mnt_idmap *idmap,
1144 struct dentry *dentry, struct posix_acl *acl,
1145 int type)
1146{
1147 int rc;
1148 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
1149 struct inode *lower_inode = d_inode(lower_dentry);
1150
1151 rc = vfs_set_acl(&nop_mnt_idmap, lower_dentry,
1152 posix_acl_xattr_name(type), acl);
1153 if (!rc)
1154 fsstack_copy_attr_all(d_inode(dentry), lower_inode);
1155 return rc;
1156}
1157
1158const struct inode_operations ecryptfs_symlink_iops = {
1159 .get_link = ecryptfs_get_link,
1160 .permission = ecryptfs_permission,
1161 .setattr = ecryptfs_setattr,
1162 .getattr = ecryptfs_getattr_link,
1163 .listxattr = ecryptfs_listxattr,
1164};
1165
1166const struct inode_operations ecryptfs_dir_iops = {
1167 .create = ecryptfs_create,
1168 .lookup = ecryptfs_lookup,
1169 .link = ecryptfs_link,
1170 .unlink = ecryptfs_unlink,
1171 .symlink = ecryptfs_symlink,
1172 .mkdir = ecryptfs_mkdir,
1173 .rmdir = ecryptfs_rmdir,
1174 .mknod = ecryptfs_mknod,
1175 .rename = ecryptfs_rename,
1176 .permission = ecryptfs_permission,
1177 .setattr = ecryptfs_setattr,
1178 .listxattr = ecryptfs_listxattr,
1179 .fileattr_get = ecryptfs_fileattr_get,
1180 .fileattr_set = ecryptfs_fileattr_set,
1181 .get_acl = ecryptfs_get_acl,
1182 .set_acl = ecryptfs_set_acl,
1183};
1184
1185const struct inode_operations ecryptfs_main_iops = {
1186 .permission = ecryptfs_permission,
1187 .setattr = ecryptfs_setattr,
1188 .getattr = ecryptfs_getattr,
1189 .listxattr = ecryptfs_listxattr,
1190 .fileattr_get = ecryptfs_fileattr_get,
1191 .fileattr_set = ecryptfs_fileattr_set,
1192 .get_acl = ecryptfs_get_acl,
1193 .set_acl = ecryptfs_set_acl,
1194};
1195
1196static int ecryptfs_xattr_get(const struct xattr_handler *handler,
1197 struct dentry *dentry, struct inode *inode,
1198 const char *name, void *buffer, size_t size)
1199{
1200 return ecryptfs_getxattr(dentry, inode, name, buffer, size);
1201}
1202
1203static int ecryptfs_xattr_set(const struct xattr_handler *handler,
1204 struct mnt_idmap *idmap,
1205 struct dentry *dentry, struct inode *inode,
1206 const char *name, const void *value, size_t size,
1207 int flags)
1208{
1209 if (value)
1210 return ecryptfs_setxattr(dentry, inode, name, value, size, flags);
1211 else {
1212 BUG_ON(flags != XATTR_REPLACE);
1213 return ecryptfs_removexattr(dentry, inode, name);
1214 }
1215}
1216
1217static const struct xattr_handler ecryptfs_xattr_handler = {
1218 .prefix = "", /* match anything */
1219 .get = ecryptfs_xattr_get,
1220 .set = ecryptfs_xattr_set,
1221};
1222
1223const struct xattr_handler * const ecryptfs_xattr_handlers[] = {
1224 &ecryptfs_xattr_handler,
1225 NULL
1226};