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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 <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};
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};