Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jlbec...
[deliverable/linux.git] / fs / ecryptfs / inode.c
1 /**
2 * eCryptfs: Linux filesystem encryption layer
3 *
4 * Copyright (C) 1997-2004 Erez Zadok
5 * Copyright (C) 2001-2004 Stony Brook University
6 * Copyright (C) 2004-2007 International Business Machines Corp.
7 * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
8 * Michael C. Thompsion <mcthomps@us.ibm.com>
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License as
12 * published by the Free Software Foundation; either version 2 of the
13 * License, or (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
23 * 02111-1307, USA.
24 */
25
26 #include <linux/file.h>
27 #include <linux/vmalloc.h>
28 #include <linux/pagemap.h>
29 #include <linux/dcache.h>
30 #include <linux/namei.h>
31 #include <linux/mount.h>
32 #include <linux/crypto.h>
33 #include <linux/fs_stack.h>
34 #include <linux/slab.h>
35 #include <linux/xattr.h>
36 #include <asm/unaligned.h>
37 #include "ecryptfs_kernel.h"
38
39 static struct dentry *lock_parent(struct dentry *dentry)
40 {
41 struct dentry *dir;
42
43 dir = dget_parent(dentry);
44 mutex_lock_nested(&(dir->d_inode->i_mutex), I_MUTEX_PARENT);
45 return dir;
46 }
47
48 static void unlock_dir(struct dentry *dir)
49 {
50 mutex_unlock(&dir->d_inode->i_mutex);
51 dput(dir);
52 }
53
54 /**
55 * ecryptfs_create_underlying_file
56 * @lower_dir_inode: inode of the parent in the lower fs of the new file
57 * @dentry: New file's dentry
58 * @mode: The mode of the new file
59 * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
60 *
61 * Creates the file in the lower file system.
62 *
63 * Returns zero on success; non-zero on error condition
64 */
65 static int
66 ecryptfs_create_underlying_file(struct inode *lower_dir_inode,
67 struct dentry *dentry, int mode,
68 struct nameidata *nd)
69 {
70 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
71 struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
72 struct dentry *dentry_save;
73 struct vfsmount *vfsmount_save;
74 unsigned int flags_save;
75 int rc;
76
77 if (nd) {
78 dentry_save = nd->path.dentry;
79 vfsmount_save = nd->path.mnt;
80 flags_save = nd->flags;
81 nd->path.dentry = lower_dentry;
82 nd->path.mnt = lower_mnt;
83 nd->flags &= ~LOOKUP_OPEN;
84 }
85 rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd);
86 if (nd) {
87 nd->path.dentry = dentry_save;
88 nd->path.mnt = vfsmount_save;
89 nd->flags = flags_save;
90 }
91 return rc;
92 }
93
94 /**
95 * ecryptfs_do_create
96 * @directory_inode: inode of the new file's dentry's parent in ecryptfs
97 * @ecryptfs_dentry: New file's dentry in ecryptfs
98 * @mode: The mode of the new file
99 * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
100 *
101 * Creates the underlying file and the eCryptfs inode which will link to
102 * it. It will also update the eCryptfs directory inode to mimic the
103 * stat of the lower directory inode.
104 *
105 * Returns zero on success; non-zero on error condition
106 */
107 static int
108 ecryptfs_do_create(struct inode *directory_inode,
109 struct dentry *ecryptfs_dentry, int mode,
110 struct nameidata *nd)
111 {
112 int rc;
113 struct dentry *lower_dentry;
114 struct dentry *lower_dir_dentry;
115
116 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
117 lower_dir_dentry = lock_parent(lower_dentry);
118 if (IS_ERR(lower_dir_dentry)) {
119 ecryptfs_printk(KERN_ERR, "Error locking directory of "
120 "dentry\n");
121 rc = PTR_ERR(lower_dir_dentry);
122 goto out;
123 }
124 rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
125 ecryptfs_dentry, mode, nd);
126 if (rc) {
127 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
128 "rc = [%d]\n", __func__, rc);
129 goto out_lock;
130 }
131 rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
132 directory_inode->i_sb, 0);
133 if (rc) {
134 ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n");
135 goto out_lock;
136 }
137 fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
138 fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode);
139 out_lock:
140 unlock_dir(lower_dir_dentry);
141 out:
142 return rc;
143 }
144
145 /**
146 * ecryptfs_initialize_file
147 *
148 * Cause the file to be changed from a basic empty file to an ecryptfs
149 * file with a header and first data page.
150 *
151 * Returns zero on success
152 */
153 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
154 {
155 struct ecryptfs_crypt_stat *crypt_stat =
156 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
157 int rc = 0;
158
159 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
160 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
161 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
162 goto out;
163 }
164 ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
165 rc = ecryptfs_new_file_context(ecryptfs_dentry);
166 if (rc) {
167 ecryptfs_printk(KERN_ERR, "Error creating new file "
168 "context; rc = [%d]\n", rc);
169 goto out;
170 }
171 rc = ecryptfs_get_lower_file(ecryptfs_dentry);
172 if (rc) {
173 printk(KERN_ERR "%s: Error attempting to initialize "
174 "the lower file for the dentry with name "
175 "[%s]; rc = [%d]\n", __func__,
176 ecryptfs_dentry->d_name.name, rc);
177 goto out;
178 }
179 rc = ecryptfs_write_metadata(ecryptfs_dentry);
180 if (rc)
181 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
182 ecryptfs_put_lower_file(ecryptfs_dentry->d_inode);
183 out:
184 return rc;
185 }
186
187 /**
188 * ecryptfs_create
189 * @dir: The inode of the directory in which to create the file.
190 * @dentry: The eCryptfs dentry
191 * @mode: The mode of the new file.
192 * @nd: nameidata
193 *
194 * Creates a new file.
195 *
196 * Returns zero on success; non-zero on error condition
197 */
198 static int
199 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
200 int mode, struct nameidata *nd)
201 {
202 int rc;
203
204 /* ecryptfs_do_create() calls ecryptfs_interpose() */
205 rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
206 if (unlikely(rc)) {
207 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
208 "lower filesystem\n");
209 goto out;
210 }
211 /* At this point, a file exists on "disk"; we need to make sure
212 * that this on disk file is prepared to be an ecryptfs file */
213 rc = ecryptfs_initialize_file(ecryptfs_dentry);
214 out:
215 return rc;
216 }
217
218 /**
219 * ecryptfs_lookup_and_interpose_lower - Perform a lookup
220 */
221 int ecryptfs_lookup_and_interpose_lower(struct dentry *ecryptfs_dentry,
222 struct dentry *lower_dentry,
223 struct inode *ecryptfs_dir_inode)
224 {
225 struct dentry *lower_dir_dentry;
226 struct vfsmount *lower_mnt;
227 struct inode *lower_inode;
228 struct ecryptfs_crypt_stat *crypt_stat;
229 char *page_virt = NULL;
230 int put_lower = 0, rc = 0;
231
232 lower_dir_dentry = lower_dentry->d_parent;
233 lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(
234 ecryptfs_dentry->d_parent));
235 lower_inode = lower_dentry->d_inode;
236 fsstack_copy_attr_atime(ecryptfs_dir_inode, lower_dir_dentry->d_inode);
237 BUG_ON(!lower_dentry->d_count);
238 ecryptfs_set_dentry_private(ecryptfs_dentry,
239 kmem_cache_alloc(ecryptfs_dentry_info_cache,
240 GFP_KERNEL));
241 if (!ecryptfs_dentry_to_private(ecryptfs_dentry)) {
242 rc = -ENOMEM;
243 printk(KERN_ERR "%s: Out of memory whilst attempting "
244 "to allocate ecryptfs_dentry_info struct\n",
245 __func__);
246 goto out_put;
247 }
248 ecryptfs_set_dentry_lower(ecryptfs_dentry, lower_dentry);
249 ecryptfs_set_dentry_lower_mnt(ecryptfs_dentry, lower_mnt);
250 if (!lower_dentry->d_inode) {
251 /* We want to add because we couldn't find in lower */
252 d_add(ecryptfs_dentry, NULL);
253 goto out;
254 }
255 rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
256 ecryptfs_dir_inode->i_sb,
257 ECRYPTFS_INTERPOSE_FLAG_D_ADD);
258 if (rc) {
259 printk(KERN_ERR "%s: Error interposing; rc = [%d]\n",
260 __func__, rc);
261 goto out;
262 }
263 if (S_ISDIR(lower_inode->i_mode))
264 goto out;
265 if (S_ISLNK(lower_inode->i_mode))
266 goto out;
267 if (special_file(lower_inode->i_mode))
268 goto out;
269 /* Released in this function */
270 page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2, GFP_USER);
271 if (!page_virt) {
272 printk(KERN_ERR "%s: Cannot kmem_cache_zalloc() a page\n",
273 __func__);
274 rc = -ENOMEM;
275 goto out;
276 }
277 rc = ecryptfs_get_lower_file(ecryptfs_dentry);
278 if (rc) {
279 printk(KERN_ERR "%s: Error attempting to initialize "
280 "the lower file for the dentry with name "
281 "[%s]; rc = [%d]\n", __func__,
282 ecryptfs_dentry->d_name.name, rc);
283 goto out_free_kmem;
284 }
285 put_lower = 1;
286 crypt_stat = &ecryptfs_inode_to_private(
287 ecryptfs_dentry->d_inode)->crypt_stat;
288 /* TODO: lock for crypt_stat comparison */
289 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
290 ecryptfs_set_default_sizes(crypt_stat);
291 rc = ecryptfs_read_and_validate_header_region(page_virt,
292 ecryptfs_dentry->d_inode);
293 if (rc) {
294 memset(page_virt, 0, PAGE_CACHE_SIZE);
295 rc = ecryptfs_read_and_validate_xattr_region(page_virt,
296 ecryptfs_dentry);
297 if (rc) {
298 rc = 0;
299 goto out_free_kmem;
300 }
301 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
302 }
303 ecryptfs_i_size_init(page_virt, ecryptfs_dentry->d_inode);
304 out_free_kmem:
305 kmem_cache_free(ecryptfs_header_cache_2, page_virt);
306 goto out;
307 out_put:
308 dput(lower_dentry);
309 mntput(lower_mnt);
310 d_drop(ecryptfs_dentry);
311 out:
312 if (put_lower)
313 ecryptfs_put_lower_file(ecryptfs_dentry->d_inode);
314 return rc;
315 }
316
317 /**
318 * ecryptfs_lookup
319 * @ecryptfs_dir_inode: The eCryptfs directory inode
320 * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
321 * @ecryptfs_nd: nameidata; may be NULL
322 *
323 * Find a file on disk. If the file does not exist, then we'll add it to the
324 * dentry cache and continue on to read it from the disk.
325 */
326 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
327 struct dentry *ecryptfs_dentry,
328 struct nameidata *ecryptfs_nd)
329 {
330 char *encrypted_and_encoded_name = NULL;
331 size_t encrypted_and_encoded_name_size;
332 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
333 struct dentry *lower_dir_dentry, *lower_dentry;
334 int rc = 0;
335
336 if ((ecryptfs_dentry->d_name.len == 1
337 && !strcmp(ecryptfs_dentry->d_name.name, "."))
338 || (ecryptfs_dentry->d_name.len == 2
339 && !strcmp(ecryptfs_dentry->d_name.name, ".."))) {
340 goto out_d_drop;
341 }
342 lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
343 mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
344 lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name,
345 lower_dir_dentry,
346 ecryptfs_dentry->d_name.len);
347 mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
348 if (IS_ERR(lower_dentry)) {
349 rc = PTR_ERR(lower_dentry);
350 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
351 "[%d] on lower_dentry = [%s]\n", __func__, rc,
352 encrypted_and_encoded_name);
353 goto out_d_drop;
354 }
355 if (lower_dentry->d_inode)
356 goto lookup_and_interpose;
357 mount_crypt_stat = &ecryptfs_superblock_to_private(
358 ecryptfs_dentry->d_sb)->mount_crypt_stat;
359 if (!(mount_crypt_stat
360 && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)))
361 goto lookup_and_interpose;
362 dput(lower_dentry);
363 rc = ecryptfs_encrypt_and_encode_filename(
364 &encrypted_and_encoded_name, &encrypted_and_encoded_name_size,
365 NULL, mount_crypt_stat, ecryptfs_dentry->d_name.name,
366 ecryptfs_dentry->d_name.len);
367 if (rc) {
368 printk(KERN_ERR "%s: Error attempting to encrypt and encode "
369 "filename; rc = [%d]\n", __func__, rc);
370 goto out_d_drop;
371 }
372 mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
373 lower_dentry = lookup_one_len(encrypted_and_encoded_name,
374 lower_dir_dentry,
375 encrypted_and_encoded_name_size);
376 mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
377 if (IS_ERR(lower_dentry)) {
378 rc = PTR_ERR(lower_dentry);
379 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
380 "[%d] on lower_dentry = [%s]\n", __func__, rc,
381 encrypted_and_encoded_name);
382 goto out_d_drop;
383 }
384 lookup_and_interpose:
385 rc = ecryptfs_lookup_and_interpose_lower(ecryptfs_dentry, lower_dentry,
386 ecryptfs_dir_inode);
387 goto out;
388 out_d_drop:
389 d_drop(ecryptfs_dentry);
390 out:
391 kfree(encrypted_and_encoded_name);
392 return ERR_PTR(rc);
393 }
394
395 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
396 struct dentry *new_dentry)
397 {
398 struct dentry *lower_old_dentry;
399 struct dentry *lower_new_dentry;
400 struct dentry *lower_dir_dentry;
401 u64 file_size_save;
402 int rc;
403
404 file_size_save = i_size_read(old_dentry->d_inode);
405 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
406 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
407 dget(lower_old_dentry);
408 dget(lower_new_dentry);
409 lower_dir_dentry = lock_parent(lower_new_dentry);
410 rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
411 lower_new_dentry);
412 if (rc || !lower_new_dentry->d_inode)
413 goto out_lock;
414 rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
415 if (rc)
416 goto out_lock;
417 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
418 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
419 old_dentry->d_inode->i_nlink =
420 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
421 i_size_write(new_dentry->d_inode, file_size_save);
422 out_lock:
423 unlock_dir(lower_dir_dentry);
424 dput(lower_new_dentry);
425 dput(lower_old_dentry);
426 return rc;
427 }
428
429 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
430 {
431 int rc = 0;
432 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
433 struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
434 struct dentry *lower_dir_dentry;
435
436 dget(lower_dentry);
437 lower_dir_dentry = lock_parent(lower_dentry);
438 rc = vfs_unlink(lower_dir_inode, lower_dentry);
439 if (rc) {
440 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
441 goto out_unlock;
442 }
443 fsstack_copy_attr_times(dir, lower_dir_inode);
444 dentry->d_inode->i_nlink =
445 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
446 dentry->d_inode->i_ctime = dir->i_ctime;
447 d_drop(dentry);
448 out_unlock:
449 unlock_dir(lower_dir_dentry);
450 dput(lower_dentry);
451 return rc;
452 }
453
454 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
455 const char *symname)
456 {
457 int rc;
458 struct dentry *lower_dentry;
459 struct dentry *lower_dir_dentry;
460 char *encoded_symname;
461 size_t encoded_symlen;
462 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
463
464 lower_dentry = ecryptfs_dentry_to_lower(dentry);
465 dget(lower_dentry);
466 lower_dir_dentry = lock_parent(lower_dentry);
467 mount_crypt_stat = &ecryptfs_superblock_to_private(
468 dir->i_sb)->mount_crypt_stat;
469 rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
470 &encoded_symlen,
471 NULL,
472 mount_crypt_stat, symname,
473 strlen(symname));
474 if (rc)
475 goto out_lock;
476 rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
477 encoded_symname);
478 kfree(encoded_symname);
479 if (rc || !lower_dentry->d_inode)
480 goto out_lock;
481 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
482 if (rc)
483 goto out_lock;
484 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
485 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
486 out_lock:
487 unlock_dir(lower_dir_dentry);
488 dput(lower_dentry);
489 if (!dentry->d_inode)
490 d_drop(dentry);
491 return rc;
492 }
493
494 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
495 {
496 int rc;
497 struct dentry *lower_dentry;
498 struct dentry *lower_dir_dentry;
499
500 lower_dentry = ecryptfs_dentry_to_lower(dentry);
501 lower_dir_dentry = lock_parent(lower_dentry);
502 rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
503 if (rc || !lower_dentry->d_inode)
504 goto out;
505 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
506 if (rc)
507 goto out;
508 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
509 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
510 dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
511 out:
512 unlock_dir(lower_dir_dentry);
513 if (!dentry->d_inode)
514 d_drop(dentry);
515 return rc;
516 }
517
518 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
519 {
520 struct dentry *lower_dentry;
521 struct dentry *lower_dir_dentry;
522 int rc;
523
524 dentry_unhash(dentry);
525
526 lower_dentry = ecryptfs_dentry_to_lower(dentry);
527 dget(dentry);
528 lower_dir_dentry = lock_parent(lower_dentry);
529 dget(lower_dentry);
530 rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
531 dput(lower_dentry);
532 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
533 dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
534 unlock_dir(lower_dir_dentry);
535 if (!rc)
536 d_drop(dentry);
537 dput(dentry);
538 return rc;
539 }
540
541 static int
542 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
543 {
544 int rc;
545 struct dentry *lower_dentry;
546 struct dentry *lower_dir_dentry;
547
548 lower_dentry = ecryptfs_dentry_to_lower(dentry);
549 lower_dir_dentry = lock_parent(lower_dentry);
550 rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
551 if (rc || !lower_dentry->d_inode)
552 goto out;
553 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
554 if (rc)
555 goto out;
556 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
557 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
558 out:
559 unlock_dir(lower_dir_dentry);
560 if (!dentry->d_inode)
561 d_drop(dentry);
562 return rc;
563 }
564
565 static int
566 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
567 struct inode *new_dir, struct dentry *new_dentry)
568 {
569 int rc;
570 struct dentry *lower_old_dentry;
571 struct dentry *lower_new_dentry;
572 struct dentry *lower_old_dir_dentry;
573 struct dentry *lower_new_dir_dentry;
574 struct dentry *trap = NULL;
575
576 if (new_dentry->d_inode && S_ISDIR(new_dentry->d_inode->i_mode))
577 dentry_unhash(new_dentry);
578
579 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
580 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
581 dget(lower_old_dentry);
582 dget(lower_new_dentry);
583 lower_old_dir_dentry = dget_parent(lower_old_dentry);
584 lower_new_dir_dentry = dget_parent(lower_new_dentry);
585 trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
586 /* source should not be ancestor of target */
587 if (trap == lower_old_dentry) {
588 rc = -EINVAL;
589 goto out_lock;
590 }
591 /* target should not be ancestor of source */
592 if (trap == lower_new_dentry) {
593 rc = -ENOTEMPTY;
594 goto out_lock;
595 }
596 rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
597 lower_new_dir_dentry->d_inode, lower_new_dentry);
598 if (rc)
599 goto out_lock;
600 fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode);
601 if (new_dir != old_dir)
602 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode);
603 out_lock:
604 unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
605 dput(lower_new_dir_dentry);
606 dput(lower_old_dir_dentry);
607 dput(lower_new_dentry);
608 dput(lower_old_dentry);
609 return rc;
610 }
611
612 static int ecryptfs_readlink_lower(struct dentry *dentry, char **buf,
613 size_t *bufsiz)
614 {
615 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
616 char *lower_buf;
617 size_t lower_bufsiz = PATH_MAX;
618 mm_segment_t old_fs;
619 int rc;
620
621 lower_buf = kmalloc(lower_bufsiz, GFP_KERNEL);
622 if (!lower_buf) {
623 rc = -ENOMEM;
624 goto out;
625 }
626 old_fs = get_fs();
627 set_fs(get_ds());
628 rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
629 (char __user *)lower_buf,
630 lower_bufsiz);
631 set_fs(old_fs);
632 if (rc < 0)
633 goto out;
634 lower_bufsiz = rc;
635 rc = ecryptfs_decode_and_decrypt_filename(buf, bufsiz, dentry,
636 lower_buf, lower_bufsiz);
637 out:
638 kfree(lower_buf);
639 return rc;
640 }
641
642 static int
643 ecryptfs_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
644 {
645 char *kbuf;
646 size_t kbufsiz, copied;
647 int rc;
648
649 rc = ecryptfs_readlink_lower(dentry, &kbuf, &kbufsiz);
650 if (rc)
651 goto out;
652 copied = min_t(size_t, bufsiz, kbufsiz);
653 rc = copy_to_user(buf, kbuf, copied) ? -EFAULT : copied;
654 kfree(kbuf);
655 fsstack_copy_attr_atime(dentry->d_inode,
656 ecryptfs_dentry_to_lower(dentry)->d_inode);
657 out:
658 return rc;
659 }
660
661 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
662 {
663 char *buf;
664 int len = PAGE_SIZE, rc;
665 mm_segment_t old_fs;
666
667 /* Released in ecryptfs_put_link(); only release here on error */
668 buf = kmalloc(len, GFP_KERNEL);
669 if (!buf) {
670 buf = ERR_PTR(-ENOMEM);
671 goto out;
672 }
673 old_fs = get_fs();
674 set_fs(get_ds());
675 rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
676 set_fs(old_fs);
677 if (rc < 0) {
678 kfree(buf);
679 buf = ERR_PTR(rc);
680 } else
681 buf[rc] = '\0';
682 out:
683 nd_set_link(nd, buf);
684 return NULL;
685 }
686
687 static void
688 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
689 {
690 char *buf = nd_get_link(nd);
691 if (!IS_ERR(buf)) {
692 /* Free the char* */
693 kfree(buf);
694 }
695 }
696
697 /**
698 * upper_size_to_lower_size
699 * @crypt_stat: Crypt_stat associated with file
700 * @upper_size: Size of the upper file
701 *
702 * Calculate the required size of the lower file based on the
703 * specified size of the upper file. This calculation is based on the
704 * number of headers in the underlying file and the extent size.
705 *
706 * Returns Calculated size of the lower file.
707 */
708 static loff_t
709 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
710 loff_t upper_size)
711 {
712 loff_t lower_size;
713
714 lower_size = ecryptfs_lower_header_size(crypt_stat);
715 if (upper_size != 0) {
716 loff_t num_extents;
717
718 num_extents = upper_size >> crypt_stat->extent_shift;
719 if (upper_size & ~crypt_stat->extent_mask)
720 num_extents++;
721 lower_size += (num_extents * crypt_stat->extent_size);
722 }
723 return lower_size;
724 }
725
726 /**
727 * truncate_upper
728 * @dentry: The ecryptfs layer dentry
729 * @ia: Address of the ecryptfs inode's attributes
730 * @lower_ia: Address of the lower inode's attributes
731 *
732 * Function to handle truncations modifying the size of the file. Note
733 * that the file sizes are interpolated. When expanding, we are simply
734 * writing strings of 0's out. When truncating, we truncate the upper
735 * inode and update the lower_ia according to the page index
736 * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
737 * the caller must use lower_ia in a call to notify_change() to perform
738 * the truncation of the lower inode.
739 *
740 * Returns zero on success; non-zero otherwise
741 */
742 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
743 struct iattr *lower_ia)
744 {
745 int rc = 0;
746 struct inode *inode = dentry->d_inode;
747 struct ecryptfs_crypt_stat *crypt_stat;
748 loff_t i_size = i_size_read(inode);
749 loff_t lower_size_before_truncate;
750 loff_t lower_size_after_truncate;
751
752 if (unlikely((ia->ia_size == i_size))) {
753 lower_ia->ia_valid &= ~ATTR_SIZE;
754 return 0;
755 }
756 rc = ecryptfs_get_lower_file(dentry);
757 if (rc)
758 return rc;
759 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
760 /* Switch on growing or shrinking file */
761 if (ia->ia_size > i_size) {
762 char zero[] = { 0x00 };
763
764 lower_ia->ia_valid &= ~ATTR_SIZE;
765 /* Write a single 0 at the last position of the file;
766 * this triggers code that will fill in 0's throughout
767 * the intermediate portion of the previous end of the
768 * file and the new and of the file */
769 rc = ecryptfs_write(inode, zero,
770 (ia->ia_size - 1), 1);
771 } else { /* ia->ia_size < i_size_read(inode) */
772 /* We're chopping off all the pages down to the page
773 * in which ia->ia_size is located. Fill in the end of
774 * that page from (ia->ia_size & ~PAGE_CACHE_MASK) to
775 * PAGE_CACHE_SIZE with zeros. */
776 size_t num_zeros = (PAGE_CACHE_SIZE
777 - (ia->ia_size & ~PAGE_CACHE_MASK));
778
779
780 /*
781 * XXX(truncate) this should really happen at the begginning
782 * of ->setattr. But the code is too messy to that as part
783 * of a larger patch. ecryptfs is also totally missing out
784 * on the inode_change_ok check at the beginning of
785 * ->setattr while would include this.
786 */
787 rc = inode_newsize_ok(inode, ia->ia_size);
788 if (rc)
789 goto out;
790
791 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
792 truncate_setsize(inode, ia->ia_size);
793 lower_ia->ia_size = ia->ia_size;
794 lower_ia->ia_valid |= ATTR_SIZE;
795 goto out;
796 }
797 if (num_zeros) {
798 char *zeros_virt;
799
800 zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
801 if (!zeros_virt) {
802 rc = -ENOMEM;
803 goto out;
804 }
805 rc = ecryptfs_write(inode, zeros_virt,
806 ia->ia_size, num_zeros);
807 kfree(zeros_virt);
808 if (rc) {
809 printk(KERN_ERR "Error attempting to zero out "
810 "the remainder of the end page on "
811 "reducing truncate; rc = [%d]\n", rc);
812 goto out;
813 }
814 }
815 truncate_setsize(inode, ia->ia_size);
816 rc = ecryptfs_write_inode_size_to_metadata(inode);
817 if (rc) {
818 printk(KERN_ERR "Problem with "
819 "ecryptfs_write_inode_size_to_metadata; "
820 "rc = [%d]\n", rc);
821 goto out;
822 }
823 /* We are reducing the size of the ecryptfs file, and need to
824 * know if we need to reduce the size of the lower file. */
825 lower_size_before_truncate =
826 upper_size_to_lower_size(crypt_stat, i_size);
827 lower_size_after_truncate =
828 upper_size_to_lower_size(crypt_stat, ia->ia_size);
829 if (lower_size_after_truncate < lower_size_before_truncate) {
830 lower_ia->ia_size = lower_size_after_truncate;
831 lower_ia->ia_valid |= ATTR_SIZE;
832 } else
833 lower_ia->ia_valid &= ~ATTR_SIZE;
834 }
835 out:
836 ecryptfs_put_lower_file(inode);
837 return rc;
838 }
839
840 /**
841 * ecryptfs_truncate
842 * @dentry: The ecryptfs layer dentry
843 * @new_length: The length to expand the file to
844 *
845 * Simple function that handles the truncation of an eCryptfs inode and
846 * its corresponding lower inode.
847 *
848 * Returns zero on success; non-zero otherwise
849 */
850 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
851 {
852 struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
853 struct iattr lower_ia = { .ia_valid = 0 };
854 int rc;
855
856 rc = truncate_upper(dentry, &ia, &lower_ia);
857 if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
858 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
859
860 mutex_lock(&lower_dentry->d_inode->i_mutex);
861 rc = notify_change(lower_dentry, &lower_ia);
862 mutex_unlock(&lower_dentry->d_inode->i_mutex);
863 }
864 return rc;
865 }
866
867 static int
868 ecryptfs_permission(struct inode *inode, int mask, unsigned int flags)
869 {
870 if (flags & IPERM_FLAG_RCU)
871 return -ECHILD;
872 return inode_permission(ecryptfs_inode_to_lower(inode), mask);
873 }
874
875 /**
876 * ecryptfs_setattr
877 * @dentry: dentry handle to the inode to modify
878 * @ia: Structure with flags of what to change and values
879 *
880 * Updates the metadata of an inode. If the update is to the size
881 * i.e. truncation, then ecryptfs_truncate will handle the size modification
882 * of both the ecryptfs inode and the lower inode.
883 *
884 * All other metadata changes will be passed right to the lower filesystem,
885 * and we will just update our inode to look like the lower.
886 */
887 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
888 {
889 int rc = 0;
890 struct dentry *lower_dentry;
891 struct iattr lower_ia;
892 struct inode *inode;
893 struct inode *lower_inode;
894 struct ecryptfs_crypt_stat *crypt_stat;
895
896 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
897 if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
898 ecryptfs_init_crypt_stat(crypt_stat);
899 inode = dentry->d_inode;
900 lower_inode = ecryptfs_inode_to_lower(inode);
901 lower_dentry = ecryptfs_dentry_to_lower(dentry);
902 mutex_lock(&crypt_stat->cs_mutex);
903 if (S_ISDIR(dentry->d_inode->i_mode))
904 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
905 else if (S_ISREG(dentry->d_inode->i_mode)
906 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
907 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
908 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
909
910 mount_crypt_stat = &ecryptfs_superblock_to_private(
911 dentry->d_sb)->mount_crypt_stat;
912 rc = ecryptfs_get_lower_file(dentry);
913 if (rc) {
914 mutex_unlock(&crypt_stat->cs_mutex);
915 goto out;
916 }
917 rc = ecryptfs_read_metadata(dentry);
918 ecryptfs_put_lower_file(inode);
919 if (rc) {
920 if (!(mount_crypt_stat->flags
921 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
922 rc = -EIO;
923 printk(KERN_WARNING "Either the lower file "
924 "is not in a valid eCryptfs format, "
925 "or the key could not be retrieved. "
926 "Plaintext passthrough mode is not "
927 "enabled; returning -EIO\n");
928 mutex_unlock(&crypt_stat->cs_mutex);
929 goto out;
930 }
931 rc = 0;
932 crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
933 | ECRYPTFS_ENCRYPTED);
934 }
935 }
936 mutex_unlock(&crypt_stat->cs_mutex);
937 if (S_ISREG(inode->i_mode)) {
938 rc = filemap_write_and_wait(inode->i_mapping);
939 if (rc)
940 goto out;
941 fsstack_copy_attr_all(inode, lower_inode);
942 }
943 memcpy(&lower_ia, ia, sizeof(lower_ia));
944 if (ia->ia_valid & ATTR_FILE)
945 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
946 if (ia->ia_valid & ATTR_SIZE) {
947 rc = truncate_upper(dentry, ia, &lower_ia);
948 if (rc < 0)
949 goto out;
950 }
951
952 /*
953 * mode change is for clearing setuid/setgid bits. Allow lower fs
954 * to interpret this in its own way.
955 */
956 if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
957 lower_ia.ia_valid &= ~ATTR_MODE;
958
959 mutex_lock(&lower_dentry->d_inode->i_mutex);
960 rc = notify_change(lower_dentry, &lower_ia);
961 mutex_unlock(&lower_dentry->d_inode->i_mutex);
962 out:
963 fsstack_copy_attr_all(inode, lower_inode);
964 return rc;
965 }
966
967 int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
968 struct kstat *stat)
969 {
970 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
971 int rc = 0;
972
973 mount_crypt_stat = &ecryptfs_superblock_to_private(
974 dentry->d_sb)->mount_crypt_stat;
975 generic_fillattr(dentry->d_inode, stat);
976 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
977 char *target;
978 size_t targetsiz;
979
980 rc = ecryptfs_readlink_lower(dentry, &target, &targetsiz);
981 if (!rc) {
982 kfree(target);
983 stat->size = targetsiz;
984 }
985 }
986 return rc;
987 }
988
989 int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
990 struct kstat *stat)
991 {
992 struct kstat lower_stat;
993 int rc;
994
995 rc = vfs_getattr(ecryptfs_dentry_to_lower_mnt(dentry),
996 ecryptfs_dentry_to_lower(dentry), &lower_stat);
997 if (!rc) {
998 fsstack_copy_attr_all(dentry->d_inode,
999 ecryptfs_inode_to_lower(dentry->d_inode));
1000 generic_fillattr(dentry->d_inode, stat);
1001 stat->blocks = lower_stat.blocks;
1002 }
1003 return rc;
1004 }
1005
1006 int
1007 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
1008 size_t size, int flags)
1009 {
1010 int rc = 0;
1011 struct dentry *lower_dentry;
1012
1013 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1014 if (!lower_dentry->d_inode->i_op->setxattr) {
1015 rc = -EOPNOTSUPP;
1016 goto out;
1017 }
1018
1019 rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1020 out:
1021 return rc;
1022 }
1023
1024 ssize_t
1025 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
1026 void *value, size_t size)
1027 {
1028 int rc = 0;
1029
1030 if (!lower_dentry->d_inode->i_op->getxattr) {
1031 rc = -EOPNOTSUPP;
1032 goto out;
1033 }
1034 mutex_lock(&lower_dentry->d_inode->i_mutex);
1035 rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
1036 size);
1037 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1038 out:
1039 return rc;
1040 }
1041
1042 static ssize_t
1043 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
1044 size_t size)
1045 {
1046 return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
1047 value, size);
1048 }
1049
1050 static ssize_t
1051 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1052 {
1053 int rc = 0;
1054 struct dentry *lower_dentry;
1055
1056 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1057 if (!lower_dentry->d_inode->i_op->listxattr) {
1058 rc = -EOPNOTSUPP;
1059 goto out;
1060 }
1061 mutex_lock(&lower_dentry->d_inode->i_mutex);
1062 rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1063 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1064 out:
1065 return rc;
1066 }
1067
1068 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1069 {
1070 int rc = 0;
1071 struct dentry *lower_dentry;
1072
1073 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1074 if (!lower_dentry->d_inode->i_op->removexattr) {
1075 rc = -EOPNOTSUPP;
1076 goto out;
1077 }
1078 mutex_lock(&lower_dentry->d_inode->i_mutex);
1079 rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1080 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1081 out:
1082 return rc;
1083 }
1084
1085 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
1086 {
1087 if ((ecryptfs_inode_to_lower(inode)
1088 == (struct inode *)candidate_lower_inode))
1089 return 1;
1090 else
1091 return 0;
1092 }
1093
1094 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1095 {
1096 ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1097 return 0;
1098 }
1099
1100 const struct inode_operations ecryptfs_symlink_iops = {
1101 .readlink = ecryptfs_readlink,
1102 .follow_link = ecryptfs_follow_link,
1103 .put_link = ecryptfs_put_link,
1104 .permission = ecryptfs_permission,
1105 .setattr = ecryptfs_setattr,
1106 .getattr = ecryptfs_getattr_link,
1107 .setxattr = ecryptfs_setxattr,
1108 .getxattr = ecryptfs_getxattr,
1109 .listxattr = ecryptfs_listxattr,
1110 .removexattr = ecryptfs_removexattr
1111 };
1112
1113 const struct inode_operations ecryptfs_dir_iops = {
1114 .create = ecryptfs_create,
1115 .lookup = ecryptfs_lookup,
1116 .link = ecryptfs_link,
1117 .unlink = ecryptfs_unlink,
1118 .symlink = ecryptfs_symlink,
1119 .mkdir = ecryptfs_mkdir,
1120 .rmdir = ecryptfs_rmdir,
1121 .mknod = ecryptfs_mknod,
1122 .rename = ecryptfs_rename,
1123 .permission = ecryptfs_permission,
1124 .setattr = ecryptfs_setattr,
1125 .setxattr = ecryptfs_setxattr,
1126 .getxattr = ecryptfs_getxattr,
1127 .listxattr = ecryptfs_listxattr,
1128 .removexattr = ecryptfs_removexattr
1129 };
1130
1131 const struct inode_operations ecryptfs_main_iops = {
1132 .permission = ecryptfs_permission,
1133 .setattr = ecryptfs_setattr,
1134 .getattr = ecryptfs_getattr,
1135 .setxattr = ecryptfs_setxattr,
1136 .getxattr = ecryptfs_getxattr,
1137 .listxattr = ecryptfs_listxattr,
1138 .removexattr = ecryptfs_removexattr
1139 };
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