f0ad965d7d5110bbbb8bfb3a9c50d4764ee8172d
[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 static int ecryptfs_inode_test(struct inode *inode, void *lower_inode)
55 {
56 if (ecryptfs_inode_to_lower(inode) == (struct inode *)lower_inode)
57 return 1;
58 return 0;
59 }
60
61 static int ecryptfs_inode_set(struct inode *inode, void *opaque)
62 {
63 struct inode *lower_inode = opaque;
64
65 ecryptfs_set_inode_lower(inode, lower_inode);
66 fsstack_copy_attr_all(inode, lower_inode);
67 /* i_size will be overwritten for encrypted regular files */
68 fsstack_copy_inode_size(inode, lower_inode);
69 inode->i_ino = lower_inode->i_ino;
70 inode->i_version++;
71 inode->i_mapping->a_ops = &ecryptfs_aops;
72
73 if (S_ISLNK(inode->i_mode))
74 inode->i_op = &ecryptfs_symlink_iops;
75 else if (S_ISDIR(inode->i_mode))
76 inode->i_op = &ecryptfs_dir_iops;
77 else
78 inode->i_op = &ecryptfs_main_iops;
79
80 if (S_ISDIR(inode->i_mode))
81 inode->i_fop = &ecryptfs_dir_fops;
82 else if (special_file(inode->i_mode))
83 init_special_inode(inode, inode->i_mode, inode->i_rdev);
84 else
85 inode->i_fop = &ecryptfs_main_fops;
86
87 return 0;
88 }
89
90 static struct inode *__ecryptfs_get_inode(struct inode *lower_inode,
91 struct super_block *sb)
92 {
93 struct inode *inode;
94
95 if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb))
96 return ERR_PTR(-EXDEV);
97 if (!igrab(lower_inode))
98 return ERR_PTR(-ESTALE);
99 inode = iget5_locked(sb, (unsigned long)lower_inode,
100 ecryptfs_inode_test, ecryptfs_inode_set,
101 lower_inode);
102 if (!inode) {
103 iput(lower_inode);
104 return ERR_PTR(-EACCES);
105 }
106 if (!(inode->i_state & I_NEW))
107 iput(lower_inode);
108
109 return inode;
110 }
111
112 struct inode *ecryptfs_get_inode(struct inode *lower_inode,
113 struct super_block *sb)
114 {
115 struct inode *inode = __ecryptfs_get_inode(lower_inode, sb);
116
117 if (!IS_ERR(inode) && (inode->i_state & I_NEW))
118 unlock_new_inode(inode);
119
120 return inode;
121 }
122
123 /**
124 * ecryptfs_interpose
125 * @lower_dentry: Existing dentry in the lower filesystem
126 * @dentry: ecryptfs' dentry
127 * @sb: ecryptfs's super_block
128 *
129 * Interposes upper and lower dentries.
130 *
131 * Returns zero on success; non-zero otherwise
132 */
133 static int ecryptfs_interpose(struct dentry *lower_dentry,
134 struct dentry *dentry, struct super_block *sb)
135 {
136 struct inode *inode = ecryptfs_get_inode(lower_dentry->d_inode, sb);
137
138 if (IS_ERR(inode))
139 return PTR_ERR(inode);
140 d_instantiate(dentry, inode);
141
142 return 0;
143 }
144
145 /**
146 * ecryptfs_create_underlying_file
147 * @lower_dir_inode: inode of the parent in the lower fs of the new file
148 * @dentry: New file's dentry
149 * @mode: The mode of the new file
150 * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
151 *
152 * Creates the file in the lower file system.
153 *
154 * Returns zero on success; non-zero on error condition
155 */
156 static int
157 ecryptfs_create_underlying_file(struct inode *lower_dir_inode,
158 struct dentry *dentry, int mode,
159 struct nameidata *nd)
160 {
161 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
162 struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
163 struct dentry *dentry_save;
164 struct vfsmount *vfsmount_save;
165 unsigned int flags_save;
166 int rc;
167
168 if (nd) {
169 dentry_save = nd->path.dentry;
170 vfsmount_save = nd->path.mnt;
171 flags_save = nd->flags;
172 nd->path.dentry = lower_dentry;
173 nd->path.mnt = lower_mnt;
174 nd->flags &= ~LOOKUP_OPEN;
175 }
176 rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd);
177 if (nd) {
178 nd->path.dentry = dentry_save;
179 nd->path.mnt = vfsmount_save;
180 nd->flags = flags_save;
181 }
182 return rc;
183 }
184
185 /**
186 * ecryptfs_do_create
187 * @directory_inode: inode of the new file's dentry's parent in ecryptfs
188 * @ecryptfs_dentry: New file's dentry in ecryptfs
189 * @mode: The mode of the new file
190 * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
191 *
192 * Creates the underlying file and the eCryptfs inode which will link to
193 * it. It will also update the eCryptfs directory inode to mimic the
194 * stat of the lower directory inode.
195 *
196 * Returns zero on success; non-zero on error condition
197 */
198 static int
199 ecryptfs_do_create(struct inode *directory_inode,
200 struct dentry *ecryptfs_dentry, int mode,
201 struct nameidata *nd)
202 {
203 int rc;
204 struct dentry *lower_dentry;
205 struct dentry *lower_dir_dentry;
206
207 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
208 lower_dir_dentry = lock_parent(lower_dentry);
209 if (IS_ERR(lower_dir_dentry)) {
210 ecryptfs_printk(KERN_ERR, "Error locking directory of "
211 "dentry\n");
212 rc = PTR_ERR(lower_dir_dentry);
213 goto out;
214 }
215 rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
216 ecryptfs_dentry, mode, nd);
217 if (rc) {
218 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
219 "rc = [%d]\n", __func__, rc);
220 goto out_lock;
221 }
222 rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
223 directory_inode->i_sb);
224 if (rc) {
225 ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n");
226 goto out_lock;
227 }
228 fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
229 fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode);
230 out_lock:
231 unlock_dir(lower_dir_dentry);
232 out:
233 return rc;
234 }
235
236 /**
237 * ecryptfs_initialize_file
238 *
239 * Cause the file to be changed from a basic empty file to an ecryptfs
240 * file with a header and first data page.
241 *
242 * Returns zero on success
243 */
244 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
245 {
246 struct ecryptfs_crypt_stat *crypt_stat =
247 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
248 int rc = 0;
249
250 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
251 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
252 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
253 goto out;
254 }
255 ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
256 rc = ecryptfs_new_file_context(ecryptfs_dentry);
257 if (rc) {
258 ecryptfs_printk(KERN_ERR, "Error creating new file "
259 "context; rc = [%d]\n", rc);
260 goto out;
261 }
262 rc = ecryptfs_get_lower_file(ecryptfs_dentry,
263 ecryptfs_dentry->d_inode);
264 if (rc) {
265 printk(KERN_ERR "%s: Error attempting to initialize "
266 "the lower file for the dentry with name "
267 "[%s]; rc = [%d]\n", __func__,
268 ecryptfs_dentry->d_name.name, rc);
269 goto out;
270 }
271 rc = ecryptfs_write_metadata(ecryptfs_dentry);
272 if (rc)
273 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
274 ecryptfs_put_lower_file(ecryptfs_dentry->d_inode);
275 out:
276 return rc;
277 }
278
279 /**
280 * ecryptfs_create
281 * @dir: The inode of the directory in which to create the file.
282 * @dentry: The eCryptfs dentry
283 * @mode: The mode of the new file.
284 * @nd: nameidata
285 *
286 * Creates a new file.
287 *
288 * Returns zero on success; non-zero on error condition
289 */
290 static int
291 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
292 int mode, struct nameidata *nd)
293 {
294 int rc;
295
296 /* ecryptfs_do_create() calls ecryptfs_interpose() */
297 rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
298 if (unlikely(rc)) {
299 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
300 "lower filesystem\n");
301 goto out;
302 }
303 /* At this point, a file exists on "disk"; we need to make sure
304 * that this on disk file is prepared to be an ecryptfs file */
305 rc = ecryptfs_initialize_file(ecryptfs_dentry);
306 out:
307 return rc;
308 }
309
310 /**
311 * ecryptfs_lookup_interpose - Dentry interposition for a lookup
312 */
313 static int ecryptfs_lookup_interpose(struct dentry *ecryptfs_dentry,
314 struct dentry *lower_dentry,
315 struct inode *ecryptfs_dir_inode)
316 {
317 struct dentry *lower_dir_dentry;
318 struct vfsmount *lower_mnt;
319 struct inode *inode, *lower_inode;
320 struct ecryptfs_crypt_stat *crypt_stat;
321 char *page_virt = NULL;
322 int put_lower = 0, rc = 0;
323
324 lower_dir_dentry = lower_dentry->d_parent;
325 lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(
326 ecryptfs_dentry->d_parent));
327 lower_inode = lower_dentry->d_inode;
328 fsstack_copy_attr_atime(ecryptfs_dir_inode, lower_dir_dentry->d_inode);
329 BUG_ON(!lower_dentry->d_count);
330 ecryptfs_set_dentry_private(ecryptfs_dentry,
331 kmem_cache_alloc(ecryptfs_dentry_info_cache,
332 GFP_KERNEL));
333 if (!ecryptfs_dentry_to_private(ecryptfs_dentry)) {
334 rc = -ENOMEM;
335 printk(KERN_ERR "%s: Out of memory whilst attempting "
336 "to allocate ecryptfs_dentry_info struct\n",
337 __func__);
338 goto out_put;
339 }
340 ecryptfs_set_dentry_lower(ecryptfs_dentry, lower_dentry);
341 ecryptfs_set_dentry_lower_mnt(ecryptfs_dentry, lower_mnt);
342 if (!lower_dentry->d_inode) {
343 /* We want to add because we couldn't find in lower */
344 d_add(ecryptfs_dentry, NULL);
345 goto out;
346 }
347 inode = __ecryptfs_get_inode(lower_inode, ecryptfs_dir_inode->i_sb);
348 if (IS_ERR(inode)) {
349 rc = PTR_ERR(inode);
350 printk(KERN_ERR "%s: Error interposing; rc = [%d]\n",
351 __func__, rc);
352 goto out;
353 }
354 if (!S_ISREG(inode->i_mode)) {
355 if (inode->i_state & I_NEW)
356 unlock_new_inode(inode);
357 d_add(ecryptfs_dentry, inode);
358 goto out;
359 }
360 /* Released in this function */
361 page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2, GFP_USER);
362 if (!page_virt) {
363 printk(KERN_ERR "%s: Cannot kmem_cache_zalloc() a page\n",
364 __func__);
365 rc = -ENOMEM;
366 make_bad_inode(inode);
367 goto out;
368 }
369 rc = ecryptfs_get_lower_file(ecryptfs_dentry, inode);
370 if (rc) {
371 printk(KERN_ERR "%s: Error attempting to initialize "
372 "the lower file for the dentry with name "
373 "[%s]; rc = [%d]\n", __func__,
374 ecryptfs_dentry->d_name.name, rc);
375 make_bad_inode(inode);
376 goto out_free_kmem;
377 }
378 put_lower = 1;
379 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
380 /* TODO: lock for crypt_stat comparison */
381 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
382 ecryptfs_set_default_sizes(crypt_stat);
383 rc = ecryptfs_read_and_validate_header_region(page_virt, inode);
384 if (rc) {
385 memset(page_virt, 0, PAGE_CACHE_SIZE);
386 rc = ecryptfs_read_and_validate_xattr_region(page_virt,
387 inode);
388 if (rc) {
389 rc = 0;
390 goto unlock_inode;
391 }
392 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
393 }
394 ecryptfs_i_size_init(page_virt, inode);
395 unlock_inode:
396 if (inode->i_state & I_NEW)
397 unlock_new_inode(inode);
398 d_add(ecryptfs_dentry, inode);
399 out_free_kmem:
400 kmem_cache_free(ecryptfs_header_cache_2, page_virt);
401 goto out;
402 out_put:
403 dput(lower_dentry);
404 mntput(lower_mnt);
405 d_drop(ecryptfs_dentry);
406 out:
407 if (put_lower)
408 ecryptfs_put_lower_file(inode);
409 return rc;
410 }
411
412 /**
413 * ecryptfs_lookup
414 * @ecryptfs_dir_inode: The eCryptfs directory inode
415 * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
416 * @ecryptfs_nd: nameidata; may be NULL
417 *
418 * Find a file on disk. If the file does not exist, then we'll add it to the
419 * dentry cache and continue on to read it from the disk.
420 */
421 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
422 struct dentry *ecryptfs_dentry,
423 struct nameidata *ecryptfs_nd)
424 {
425 char *encrypted_and_encoded_name = NULL;
426 size_t encrypted_and_encoded_name_size;
427 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
428 struct dentry *lower_dir_dentry, *lower_dentry;
429 int rc = 0;
430
431 if ((ecryptfs_dentry->d_name.len == 1
432 && !strcmp(ecryptfs_dentry->d_name.name, "."))
433 || (ecryptfs_dentry->d_name.len == 2
434 && !strcmp(ecryptfs_dentry->d_name.name, ".."))) {
435 goto out_d_drop;
436 }
437 lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
438 mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
439 lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name,
440 lower_dir_dentry,
441 ecryptfs_dentry->d_name.len);
442 mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
443 if (IS_ERR(lower_dentry)) {
444 rc = PTR_ERR(lower_dentry);
445 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
446 "[%d] on lower_dentry = [%s]\n", __func__, rc,
447 encrypted_and_encoded_name);
448 goto out_d_drop;
449 }
450 if (lower_dentry->d_inode)
451 goto interpose;
452 mount_crypt_stat = &ecryptfs_superblock_to_private(
453 ecryptfs_dentry->d_sb)->mount_crypt_stat;
454 if (!(mount_crypt_stat
455 && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)))
456 goto interpose;
457 dput(lower_dentry);
458 rc = ecryptfs_encrypt_and_encode_filename(
459 &encrypted_and_encoded_name, &encrypted_and_encoded_name_size,
460 NULL, mount_crypt_stat, ecryptfs_dentry->d_name.name,
461 ecryptfs_dentry->d_name.len);
462 if (rc) {
463 printk(KERN_ERR "%s: Error attempting to encrypt and encode "
464 "filename; rc = [%d]\n", __func__, rc);
465 goto out_d_drop;
466 }
467 mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
468 lower_dentry = lookup_one_len(encrypted_and_encoded_name,
469 lower_dir_dentry,
470 encrypted_and_encoded_name_size);
471 mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
472 if (IS_ERR(lower_dentry)) {
473 rc = PTR_ERR(lower_dentry);
474 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
475 "[%d] on lower_dentry = [%s]\n", __func__, rc,
476 encrypted_and_encoded_name);
477 goto out_d_drop;
478 }
479 interpose:
480 rc = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry,
481 ecryptfs_dir_inode);
482 goto out;
483 out_d_drop:
484 d_drop(ecryptfs_dentry);
485 out:
486 kfree(encrypted_and_encoded_name);
487 return ERR_PTR(rc);
488 }
489
490 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
491 struct dentry *new_dentry)
492 {
493 struct dentry *lower_old_dentry;
494 struct dentry *lower_new_dentry;
495 struct dentry *lower_dir_dentry;
496 u64 file_size_save;
497 int rc;
498
499 file_size_save = i_size_read(old_dentry->d_inode);
500 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
501 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
502 dget(lower_old_dentry);
503 dget(lower_new_dentry);
504 lower_dir_dentry = lock_parent(lower_new_dentry);
505 rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
506 lower_new_dentry);
507 if (rc || !lower_new_dentry->d_inode)
508 goto out_lock;
509 rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
510 if (rc)
511 goto out_lock;
512 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
513 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
514 old_dentry->d_inode->i_nlink =
515 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
516 i_size_write(new_dentry->d_inode, file_size_save);
517 out_lock:
518 unlock_dir(lower_dir_dentry);
519 dput(lower_new_dentry);
520 dput(lower_old_dentry);
521 return rc;
522 }
523
524 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
525 {
526 int rc = 0;
527 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
528 struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
529 struct dentry *lower_dir_dentry;
530
531 dget(lower_dentry);
532 lower_dir_dentry = lock_parent(lower_dentry);
533 rc = vfs_unlink(lower_dir_inode, lower_dentry);
534 if (rc) {
535 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
536 goto out_unlock;
537 }
538 fsstack_copy_attr_times(dir, lower_dir_inode);
539 dentry->d_inode->i_nlink =
540 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
541 dentry->d_inode->i_ctime = dir->i_ctime;
542 d_drop(dentry);
543 out_unlock:
544 unlock_dir(lower_dir_dentry);
545 dput(lower_dentry);
546 return rc;
547 }
548
549 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
550 const char *symname)
551 {
552 int rc;
553 struct dentry *lower_dentry;
554 struct dentry *lower_dir_dentry;
555 char *encoded_symname;
556 size_t encoded_symlen;
557 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
558
559 lower_dentry = ecryptfs_dentry_to_lower(dentry);
560 dget(lower_dentry);
561 lower_dir_dentry = lock_parent(lower_dentry);
562 mount_crypt_stat = &ecryptfs_superblock_to_private(
563 dir->i_sb)->mount_crypt_stat;
564 rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
565 &encoded_symlen,
566 NULL,
567 mount_crypt_stat, symname,
568 strlen(symname));
569 if (rc)
570 goto out_lock;
571 rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
572 encoded_symname);
573 kfree(encoded_symname);
574 if (rc || !lower_dentry->d_inode)
575 goto out_lock;
576 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
577 if (rc)
578 goto out_lock;
579 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
580 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
581 out_lock:
582 unlock_dir(lower_dir_dentry);
583 dput(lower_dentry);
584 if (!dentry->d_inode)
585 d_drop(dentry);
586 return rc;
587 }
588
589 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
590 {
591 int rc;
592 struct dentry *lower_dentry;
593 struct dentry *lower_dir_dentry;
594
595 lower_dentry = ecryptfs_dentry_to_lower(dentry);
596 lower_dir_dentry = lock_parent(lower_dentry);
597 rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
598 if (rc || !lower_dentry->d_inode)
599 goto out;
600 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
601 if (rc)
602 goto out;
603 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
604 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
605 dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
606 out:
607 unlock_dir(lower_dir_dentry);
608 if (!dentry->d_inode)
609 d_drop(dentry);
610 return rc;
611 }
612
613 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
614 {
615 struct dentry *lower_dentry;
616 struct dentry *lower_dir_dentry;
617 int rc;
618
619 lower_dentry = ecryptfs_dentry_to_lower(dentry);
620 dget(dentry);
621 lower_dir_dentry = lock_parent(lower_dentry);
622 dget(lower_dentry);
623 rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
624 dput(lower_dentry);
625 if (!rc && dentry->d_inode)
626 clear_nlink(dentry->d_inode);
627 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
628 dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
629 unlock_dir(lower_dir_dentry);
630 if (!rc)
631 d_drop(dentry);
632 dput(dentry);
633 return rc;
634 }
635
636 static int
637 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
638 {
639 int rc;
640 struct dentry *lower_dentry;
641 struct dentry *lower_dir_dentry;
642
643 lower_dentry = ecryptfs_dentry_to_lower(dentry);
644 lower_dir_dentry = lock_parent(lower_dentry);
645 rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
646 if (rc || !lower_dentry->d_inode)
647 goto out;
648 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
649 if (rc)
650 goto out;
651 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
652 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
653 out:
654 unlock_dir(lower_dir_dentry);
655 if (!dentry->d_inode)
656 d_drop(dentry);
657 return rc;
658 }
659
660 static int
661 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
662 struct inode *new_dir, struct dentry *new_dentry)
663 {
664 int rc;
665 struct dentry *lower_old_dentry;
666 struct dentry *lower_new_dentry;
667 struct dentry *lower_old_dir_dentry;
668 struct dentry *lower_new_dir_dentry;
669 struct dentry *trap = NULL;
670
671 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
672 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
673 dget(lower_old_dentry);
674 dget(lower_new_dentry);
675 lower_old_dir_dentry = dget_parent(lower_old_dentry);
676 lower_new_dir_dentry = dget_parent(lower_new_dentry);
677 trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
678 /* source should not be ancestor of target */
679 if (trap == lower_old_dentry) {
680 rc = -EINVAL;
681 goto out_lock;
682 }
683 /* target should not be ancestor of source */
684 if (trap == lower_new_dentry) {
685 rc = -ENOTEMPTY;
686 goto out_lock;
687 }
688 rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
689 lower_new_dir_dentry->d_inode, lower_new_dentry);
690 if (rc)
691 goto out_lock;
692 fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode);
693 if (new_dir != old_dir)
694 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode);
695 out_lock:
696 unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
697 dput(lower_new_dir_dentry);
698 dput(lower_old_dir_dentry);
699 dput(lower_new_dentry);
700 dput(lower_old_dentry);
701 return rc;
702 }
703
704 static int ecryptfs_readlink_lower(struct dentry *dentry, char **buf,
705 size_t *bufsiz)
706 {
707 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
708 char *lower_buf;
709 size_t lower_bufsiz = PATH_MAX;
710 mm_segment_t old_fs;
711 int rc;
712
713 lower_buf = kmalloc(lower_bufsiz, GFP_KERNEL);
714 if (!lower_buf) {
715 rc = -ENOMEM;
716 goto out;
717 }
718 old_fs = get_fs();
719 set_fs(get_ds());
720 rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
721 (char __user *)lower_buf,
722 lower_bufsiz);
723 set_fs(old_fs);
724 if (rc < 0)
725 goto out;
726 lower_bufsiz = rc;
727 rc = ecryptfs_decode_and_decrypt_filename(buf, bufsiz, dentry,
728 lower_buf, lower_bufsiz);
729 out:
730 kfree(lower_buf);
731 return rc;
732 }
733
734 static int
735 ecryptfs_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
736 {
737 char *kbuf;
738 size_t kbufsiz, copied;
739 int rc;
740
741 rc = ecryptfs_readlink_lower(dentry, &kbuf, &kbufsiz);
742 if (rc)
743 goto out;
744 copied = min_t(size_t, bufsiz, kbufsiz);
745 rc = copy_to_user(buf, kbuf, copied) ? -EFAULT : copied;
746 kfree(kbuf);
747 fsstack_copy_attr_atime(dentry->d_inode,
748 ecryptfs_dentry_to_lower(dentry)->d_inode);
749 out:
750 return rc;
751 }
752
753 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
754 {
755 char *buf;
756 int len = PAGE_SIZE, rc;
757 mm_segment_t old_fs;
758
759 /* Released in ecryptfs_put_link(); only release here on error */
760 buf = kmalloc(len, GFP_KERNEL);
761 if (!buf) {
762 buf = ERR_PTR(-ENOMEM);
763 goto out;
764 }
765 old_fs = get_fs();
766 set_fs(get_ds());
767 rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
768 set_fs(old_fs);
769 if (rc < 0) {
770 kfree(buf);
771 buf = ERR_PTR(rc);
772 } else
773 buf[rc] = '\0';
774 out:
775 nd_set_link(nd, buf);
776 return NULL;
777 }
778
779 static void
780 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
781 {
782 char *buf = nd_get_link(nd);
783 if (!IS_ERR(buf)) {
784 /* Free the char* */
785 kfree(buf);
786 }
787 }
788
789 /**
790 * upper_size_to_lower_size
791 * @crypt_stat: Crypt_stat associated with file
792 * @upper_size: Size of the upper file
793 *
794 * Calculate the required size of the lower file based on the
795 * specified size of the upper file. This calculation is based on the
796 * number of headers in the underlying file and the extent size.
797 *
798 * Returns Calculated size of the lower file.
799 */
800 static loff_t
801 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
802 loff_t upper_size)
803 {
804 loff_t lower_size;
805
806 lower_size = ecryptfs_lower_header_size(crypt_stat);
807 if (upper_size != 0) {
808 loff_t num_extents;
809
810 num_extents = upper_size >> crypt_stat->extent_shift;
811 if (upper_size & ~crypt_stat->extent_mask)
812 num_extents++;
813 lower_size += (num_extents * crypt_stat->extent_size);
814 }
815 return lower_size;
816 }
817
818 /**
819 * truncate_upper
820 * @dentry: The ecryptfs layer dentry
821 * @ia: Address of the ecryptfs inode's attributes
822 * @lower_ia: Address of the lower inode's attributes
823 *
824 * Function to handle truncations modifying the size of the file. Note
825 * that the file sizes are interpolated. When expanding, we are simply
826 * writing strings of 0's out. When truncating, we truncate the upper
827 * inode and update the lower_ia according to the page index
828 * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
829 * the caller must use lower_ia in a call to notify_change() to perform
830 * the truncation of the lower inode.
831 *
832 * Returns zero on success; non-zero otherwise
833 */
834 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
835 struct iattr *lower_ia)
836 {
837 int rc = 0;
838 struct inode *inode = dentry->d_inode;
839 struct ecryptfs_crypt_stat *crypt_stat;
840 loff_t i_size = i_size_read(inode);
841 loff_t lower_size_before_truncate;
842 loff_t lower_size_after_truncate;
843
844 if (unlikely((ia->ia_size == i_size))) {
845 lower_ia->ia_valid &= ~ATTR_SIZE;
846 return 0;
847 }
848 rc = ecryptfs_get_lower_file(dentry, inode);
849 if (rc)
850 return rc;
851 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
852 /* Switch on growing or shrinking file */
853 if (ia->ia_size > i_size) {
854 char zero[] = { 0x00 };
855
856 lower_ia->ia_valid &= ~ATTR_SIZE;
857 /* Write a single 0 at the last position of the file;
858 * this triggers code that will fill in 0's throughout
859 * the intermediate portion of the previous end of the
860 * file and the new and of the file */
861 rc = ecryptfs_write(inode, zero,
862 (ia->ia_size - 1), 1);
863 } else { /* ia->ia_size < i_size_read(inode) */
864 /* We're chopping off all the pages down to the page
865 * in which ia->ia_size is located. Fill in the end of
866 * that page from (ia->ia_size & ~PAGE_CACHE_MASK) to
867 * PAGE_CACHE_SIZE with zeros. */
868 size_t num_zeros = (PAGE_CACHE_SIZE
869 - (ia->ia_size & ~PAGE_CACHE_MASK));
870
871
872 /*
873 * XXX(truncate) this should really happen at the begginning
874 * of ->setattr. But the code is too messy to that as part
875 * of a larger patch. ecryptfs is also totally missing out
876 * on the inode_change_ok check at the beginning of
877 * ->setattr while would include this.
878 */
879 rc = inode_newsize_ok(inode, ia->ia_size);
880 if (rc)
881 goto out;
882
883 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
884 truncate_setsize(inode, ia->ia_size);
885 lower_ia->ia_size = ia->ia_size;
886 lower_ia->ia_valid |= ATTR_SIZE;
887 goto out;
888 }
889 if (num_zeros) {
890 char *zeros_virt;
891
892 zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
893 if (!zeros_virt) {
894 rc = -ENOMEM;
895 goto out;
896 }
897 rc = ecryptfs_write(inode, zeros_virt,
898 ia->ia_size, num_zeros);
899 kfree(zeros_virt);
900 if (rc) {
901 printk(KERN_ERR "Error attempting to zero out "
902 "the remainder of the end page on "
903 "reducing truncate; rc = [%d]\n", rc);
904 goto out;
905 }
906 }
907 truncate_setsize(inode, ia->ia_size);
908 rc = ecryptfs_write_inode_size_to_metadata(inode);
909 if (rc) {
910 printk(KERN_ERR "Problem with "
911 "ecryptfs_write_inode_size_to_metadata; "
912 "rc = [%d]\n", rc);
913 goto out;
914 }
915 /* We are reducing the size of the ecryptfs file, and need to
916 * know if we need to reduce the size of the lower file. */
917 lower_size_before_truncate =
918 upper_size_to_lower_size(crypt_stat, i_size);
919 lower_size_after_truncate =
920 upper_size_to_lower_size(crypt_stat, ia->ia_size);
921 if (lower_size_after_truncate < lower_size_before_truncate) {
922 lower_ia->ia_size = lower_size_after_truncate;
923 lower_ia->ia_valid |= ATTR_SIZE;
924 } else
925 lower_ia->ia_valid &= ~ATTR_SIZE;
926 }
927 out:
928 ecryptfs_put_lower_file(inode);
929 return rc;
930 }
931
932 /**
933 * ecryptfs_truncate
934 * @dentry: The ecryptfs layer dentry
935 * @new_length: The length to expand the file to
936 *
937 * Simple function that handles the truncation of an eCryptfs inode and
938 * its corresponding lower inode.
939 *
940 * Returns zero on success; non-zero otherwise
941 */
942 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
943 {
944 struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
945 struct iattr lower_ia = { .ia_valid = 0 };
946 int rc;
947
948 rc = truncate_upper(dentry, &ia, &lower_ia);
949 if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
950 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
951
952 mutex_lock(&lower_dentry->d_inode->i_mutex);
953 rc = notify_change(lower_dentry, &lower_ia);
954 mutex_unlock(&lower_dentry->d_inode->i_mutex);
955 }
956 return rc;
957 }
958
959 static int
960 ecryptfs_permission(struct inode *inode, int mask, unsigned int flags)
961 {
962 if (flags & IPERM_FLAG_RCU)
963 return -ECHILD;
964 return inode_permission(ecryptfs_inode_to_lower(inode), mask);
965 }
966
967 /**
968 * ecryptfs_setattr
969 * @dentry: dentry handle to the inode to modify
970 * @ia: Structure with flags of what to change and values
971 *
972 * Updates the metadata of an inode. If the update is to the size
973 * i.e. truncation, then ecryptfs_truncate will handle the size modification
974 * of both the ecryptfs inode and the lower inode.
975 *
976 * All other metadata changes will be passed right to the lower filesystem,
977 * and we will just update our inode to look like the lower.
978 */
979 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
980 {
981 int rc = 0;
982 struct dentry *lower_dentry;
983 struct iattr lower_ia;
984 struct inode *inode;
985 struct inode *lower_inode;
986 struct ecryptfs_crypt_stat *crypt_stat;
987
988 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
989 if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
990 ecryptfs_init_crypt_stat(crypt_stat);
991 inode = dentry->d_inode;
992 lower_inode = ecryptfs_inode_to_lower(inode);
993 lower_dentry = ecryptfs_dentry_to_lower(dentry);
994 mutex_lock(&crypt_stat->cs_mutex);
995 if (S_ISDIR(dentry->d_inode->i_mode))
996 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
997 else if (S_ISREG(dentry->d_inode->i_mode)
998 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
999 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
1000 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
1001
1002 mount_crypt_stat = &ecryptfs_superblock_to_private(
1003 dentry->d_sb)->mount_crypt_stat;
1004 rc = ecryptfs_get_lower_file(dentry, inode);
1005 if (rc) {
1006 mutex_unlock(&crypt_stat->cs_mutex);
1007 goto out;
1008 }
1009 rc = ecryptfs_read_metadata(dentry);
1010 ecryptfs_put_lower_file(inode);
1011 if (rc) {
1012 if (!(mount_crypt_stat->flags
1013 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
1014 rc = -EIO;
1015 printk(KERN_WARNING "Either the lower file "
1016 "is not in a valid eCryptfs format, "
1017 "or the key could not be retrieved. "
1018 "Plaintext passthrough mode is not "
1019 "enabled; returning -EIO\n");
1020 mutex_unlock(&crypt_stat->cs_mutex);
1021 goto out;
1022 }
1023 rc = 0;
1024 crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
1025 | ECRYPTFS_ENCRYPTED);
1026 }
1027 }
1028 mutex_unlock(&crypt_stat->cs_mutex);
1029 if (S_ISREG(inode->i_mode)) {
1030 rc = filemap_write_and_wait(inode->i_mapping);
1031 if (rc)
1032 goto out;
1033 fsstack_copy_attr_all(inode, lower_inode);
1034 }
1035 memcpy(&lower_ia, ia, sizeof(lower_ia));
1036 if (ia->ia_valid & ATTR_FILE)
1037 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
1038 if (ia->ia_valid & ATTR_SIZE) {
1039 rc = truncate_upper(dentry, ia, &lower_ia);
1040 if (rc < 0)
1041 goto out;
1042 }
1043
1044 /*
1045 * mode change is for clearing setuid/setgid bits. Allow lower fs
1046 * to interpret this in its own way.
1047 */
1048 if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
1049 lower_ia.ia_valid &= ~ATTR_MODE;
1050
1051 mutex_lock(&lower_dentry->d_inode->i_mutex);
1052 rc = notify_change(lower_dentry, &lower_ia);
1053 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1054 out:
1055 fsstack_copy_attr_all(inode, lower_inode);
1056 return rc;
1057 }
1058
1059 int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
1060 struct kstat *stat)
1061 {
1062 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
1063 int rc = 0;
1064
1065 mount_crypt_stat = &ecryptfs_superblock_to_private(
1066 dentry->d_sb)->mount_crypt_stat;
1067 generic_fillattr(dentry->d_inode, stat);
1068 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
1069 char *target;
1070 size_t targetsiz;
1071
1072 rc = ecryptfs_readlink_lower(dentry, &target, &targetsiz);
1073 if (!rc) {
1074 kfree(target);
1075 stat->size = targetsiz;
1076 }
1077 }
1078 return rc;
1079 }
1080
1081 int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
1082 struct kstat *stat)
1083 {
1084 struct kstat lower_stat;
1085 int rc;
1086
1087 rc = vfs_getattr(ecryptfs_dentry_to_lower_mnt(dentry),
1088 ecryptfs_dentry_to_lower(dentry), &lower_stat);
1089 if (!rc) {
1090 fsstack_copy_attr_all(dentry->d_inode,
1091 ecryptfs_inode_to_lower(dentry->d_inode));
1092 generic_fillattr(dentry->d_inode, stat);
1093 stat->blocks = lower_stat.blocks;
1094 }
1095 return rc;
1096 }
1097
1098 int
1099 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
1100 size_t size, int flags)
1101 {
1102 int rc = 0;
1103 struct dentry *lower_dentry;
1104
1105 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1106 if (!lower_dentry->d_inode->i_op->setxattr) {
1107 rc = -EOPNOTSUPP;
1108 goto out;
1109 }
1110
1111 rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1112 out:
1113 return rc;
1114 }
1115
1116 ssize_t
1117 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
1118 void *value, size_t size)
1119 {
1120 int rc = 0;
1121
1122 if (!lower_dentry->d_inode->i_op->getxattr) {
1123 rc = -EOPNOTSUPP;
1124 goto out;
1125 }
1126 mutex_lock(&lower_dentry->d_inode->i_mutex);
1127 rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
1128 size);
1129 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1130 out:
1131 return rc;
1132 }
1133
1134 static ssize_t
1135 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
1136 size_t size)
1137 {
1138 return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
1139 value, size);
1140 }
1141
1142 static ssize_t
1143 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1144 {
1145 int rc = 0;
1146 struct dentry *lower_dentry;
1147
1148 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1149 if (!lower_dentry->d_inode->i_op->listxattr) {
1150 rc = -EOPNOTSUPP;
1151 goto out;
1152 }
1153 mutex_lock(&lower_dentry->d_inode->i_mutex);
1154 rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1155 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1156 out:
1157 return rc;
1158 }
1159
1160 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1161 {
1162 int rc = 0;
1163 struct dentry *lower_dentry;
1164
1165 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1166 if (!lower_dentry->d_inode->i_op->removexattr) {
1167 rc = -EOPNOTSUPP;
1168 goto out;
1169 }
1170 mutex_lock(&lower_dentry->d_inode->i_mutex);
1171 rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1172 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1173 out:
1174 return rc;
1175 }
1176
1177 const struct inode_operations ecryptfs_symlink_iops = {
1178 .readlink = ecryptfs_readlink,
1179 .follow_link = ecryptfs_follow_link,
1180 .put_link = ecryptfs_put_link,
1181 .permission = ecryptfs_permission,
1182 .setattr = ecryptfs_setattr,
1183 .getattr = ecryptfs_getattr_link,
1184 .setxattr = ecryptfs_setxattr,
1185 .getxattr = ecryptfs_getxattr,
1186 .listxattr = ecryptfs_listxattr,
1187 .removexattr = ecryptfs_removexattr
1188 };
1189
1190 const struct inode_operations ecryptfs_dir_iops = {
1191 .create = ecryptfs_create,
1192 .lookup = ecryptfs_lookup,
1193 .link = ecryptfs_link,
1194 .unlink = ecryptfs_unlink,
1195 .symlink = ecryptfs_symlink,
1196 .mkdir = ecryptfs_mkdir,
1197 .rmdir = ecryptfs_rmdir,
1198 .mknod = ecryptfs_mknod,
1199 .rename = ecryptfs_rename,
1200 .permission = ecryptfs_permission,
1201 .setattr = ecryptfs_setattr,
1202 .setxattr = ecryptfs_setxattr,
1203 .getxattr = ecryptfs_getxattr,
1204 .listxattr = ecryptfs_listxattr,
1205 .removexattr = ecryptfs_removexattr
1206 };
1207
1208 const struct inode_operations ecryptfs_main_iops = {
1209 .permission = ecryptfs_permission,
1210 .setattr = ecryptfs_setattr,
1211 .getattr = ecryptfs_getattr,
1212 .setxattr = ecryptfs_setxattr,
1213 .getxattr = ecryptfs_getxattr,
1214 .listxattr = ecryptfs_listxattr,
1215 .removexattr = ecryptfs_removexattr
1216 };
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