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