Merge tag 'ecryptfs-4.15-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel...
[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         unlock_new_inode(ecryptfs_inode);
287         d_instantiate(ecryptfs_dentry, ecryptfs_inode);
288 out:
289         return rc;
290 }
291
292 static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode)
293 {
294         struct ecryptfs_crypt_stat *crypt_stat;
295         int rc;
296
297         rc = ecryptfs_get_lower_file(dentry, inode);
298         if (rc) {
299                 printk(KERN_ERR "%s: Error attempting to initialize "
300                         "the lower file for the dentry with name "
301                         "[%pd]; rc = [%d]\n", __func__,
302                         dentry, rc);
303                 return rc;
304         }
305
306         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
307         /* TODO: lock for crypt_stat comparison */
308         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
309                 ecryptfs_set_default_sizes(crypt_stat);
310
311         rc = ecryptfs_read_and_validate_header_region(inode);
312         ecryptfs_put_lower_file(inode);
313         if (rc) {
314                 rc = ecryptfs_read_and_validate_xattr_region(dentry, inode);
315                 if (!rc)
316                         crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
317         }
318
319         /* Must return 0 to allow non-eCryptfs files to be looked up, too */
320         return 0;
321 }
322
323 /**
324  * ecryptfs_lookup_interpose - Dentry interposition for a lookup
325  */
326 static struct dentry *ecryptfs_lookup_interpose(struct dentry *dentry,
327                                      struct dentry *lower_dentry)
328 {
329         struct inode *inode, *lower_inode = d_inode(lower_dentry);
330         struct ecryptfs_dentry_info *dentry_info;
331         struct vfsmount *lower_mnt;
332         int rc = 0;
333
334         dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
335         if (!dentry_info) {
336                 dput(lower_dentry);
337                 return ERR_PTR(-ENOMEM);
338         }
339
340         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
341         fsstack_copy_attr_atime(d_inode(dentry->d_parent),
342                                 d_inode(lower_dentry->d_parent));
343         BUG_ON(!d_count(lower_dentry));
344
345         ecryptfs_set_dentry_private(dentry, dentry_info);
346         dentry_info->lower_path.mnt = lower_mnt;
347         dentry_info->lower_path.dentry = lower_dentry;
348
349         if (d_really_is_negative(lower_dentry)) {
350                 /* We want to add because we couldn't find in lower */
351                 d_add(dentry, NULL);
352                 return NULL;
353         }
354         inode = __ecryptfs_get_inode(lower_inode, dentry->d_sb);
355         if (IS_ERR(inode)) {
356                 printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
357                        __func__, PTR_ERR(inode));
358                 return ERR_CAST(inode);
359         }
360         if (S_ISREG(inode->i_mode)) {
361                 rc = ecryptfs_i_size_read(dentry, inode);
362                 if (rc) {
363                         make_bad_inode(inode);
364                         return ERR_PTR(rc);
365                 }
366         }
367
368         if (inode->i_state & I_NEW)
369                 unlock_new_inode(inode);
370         return d_splice_alias(inode, dentry);
371 }
372
373 /**
374  * ecryptfs_lookup
375  * @ecryptfs_dir_inode: The eCryptfs directory inode
376  * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
377  * @flags: lookup flags
378  *
379  * Find a file on disk. If the file does not exist, then we'll add it to the
380  * dentry cache and continue on to read it from the disk.
381  */
382 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
383                                       struct dentry *ecryptfs_dentry,
384                                       unsigned int flags)
385 {
386         char *encrypted_and_encoded_name = NULL;
387         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
388         struct dentry *lower_dir_dentry, *lower_dentry;
389         const char *name = ecryptfs_dentry->d_name.name;
390         size_t len = ecryptfs_dentry->d_name.len;
391         struct dentry *res;
392         int rc = 0;
393
394         lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
395
396         mount_crypt_stat = &ecryptfs_superblock_to_private(
397                                 ecryptfs_dentry->d_sb)->mount_crypt_stat;
398         if (mount_crypt_stat
399             && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) {
400                 rc = ecryptfs_encrypt_and_encode_filename(
401                         &encrypted_and_encoded_name, &len,
402                         mount_crypt_stat, name, len);
403                 if (rc) {
404                         printk(KERN_ERR "%s: Error attempting to encrypt and encode "
405                                "filename; rc = [%d]\n", __func__, rc);
406                         return ERR_PTR(rc);
407                 }
408                 name = encrypted_and_encoded_name;
409         }
410
411         lower_dentry = lookup_one_len_unlocked(name, lower_dir_dentry, len);
412         if (IS_ERR(lower_dentry)) {
413                 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
414                                 "[%ld] on lower_dentry = [%s]\n", __func__,
415                                 PTR_ERR(lower_dentry),
416                                 name);
417                 res = ERR_CAST(lower_dentry);
418         } else {
419                 res = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry);
420         }
421         kfree(encrypted_and_encoded_name);
422         return res;
423 }
424
425 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
426                          struct dentry *new_dentry)
427 {
428         struct dentry *lower_old_dentry;
429         struct dentry *lower_new_dentry;
430         struct dentry *lower_dir_dentry;
431         u64 file_size_save;
432         int rc;
433
434         file_size_save = i_size_read(d_inode(old_dentry));
435         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
436         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
437         dget(lower_old_dentry);
438         dget(lower_new_dentry);
439         lower_dir_dentry = lock_parent(lower_new_dentry);
440         rc = vfs_link(lower_old_dentry, d_inode(lower_dir_dentry),
441                       lower_new_dentry, NULL);
442         if (rc || d_really_is_negative(lower_new_dentry))
443                 goto out_lock;
444         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
445         if (rc)
446                 goto out_lock;
447         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
448         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
449         set_nlink(d_inode(old_dentry),
450                   ecryptfs_inode_to_lower(d_inode(old_dentry))->i_nlink);
451         i_size_write(d_inode(new_dentry), file_size_save);
452 out_lock:
453         unlock_dir(lower_dir_dentry);
454         dput(lower_new_dentry);
455         dput(lower_old_dentry);
456         return rc;
457 }
458
459 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
460 {
461         return ecryptfs_do_unlink(dir, dentry, d_inode(dentry));
462 }
463
464 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
465                             const char *symname)
466 {
467         int rc;
468         struct dentry *lower_dentry;
469         struct dentry *lower_dir_dentry;
470         char *encoded_symname;
471         size_t encoded_symlen;
472         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
473
474         lower_dentry = ecryptfs_dentry_to_lower(dentry);
475         dget(lower_dentry);
476         lower_dir_dentry = lock_parent(lower_dentry);
477         mount_crypt_stat = &ecryptfs_superblock_to_private(
478                 dir->i_sb)->mount_crypt_stat;
479         rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
480                                                   &encoded_symlen,
481                                                   mount_crypt_stat, symname,
482                                                   strlen(symname));
483         if (rc)
484                 goto out_lock;
485         rc = vfs_symlink(d_inode(lower_dir_dentry), lower_dentry,
486                          encoded_symname);
487         kfree(encoded_symname);
488         if (rc || d_really_is_negative(lower_dentry))
489                 goto out_lock;
490         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
491         if (rc)
492                 goto out_lock;
493         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
494         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
495 out_lock:
496         unlock_dir(lower_dir_dentry);
497         dput(lower_dentry);
498         if (d_really_is_negative(dentry))
499                 d_drop(dentry);
500         return rc;
501 }
502
503 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
504 {
505         int rc;
506         struct dentry *lower_dentry;
507         struct dentry *lower_dir_dentry;
508
509         lower_dentry = ecryptfs_dentry_to_lower(dentry);
510         lower_dir_dentry = lock_parent(lower_dentry);
511         rc = vfs_mkdir(d_inode(lower_dir_dentry), lower_dentry, mode);
512         if (rc || d_really_is_negative(lower_dentry))
513                 goto out;
514         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
515         if (rc)
516                 goto out;
517         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
518         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
519         set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
520 out:
521         unlock_dir(lower_dir_dentry);
522         if (d_really_is_negative(dentry))
523                 d_drop(dentry);
524         return rc;
525 }
526
527 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
528 {
529         struct dentry *lower_dentry;
530         struct dentry *lower_dir_dentry;
531         int rc;
532
533         lower_dentry = ecryptfs_dentry_to_lower(dentry);
534         dget(dentry);
535         lower_dir_dentry = lock_parent(lower_dentry);
536         dget(lower_dentry);
537         rc = vfs_rmdir(d_inode(lower_dir_dentry), lower_dentry);
538         dput(lower_dentry);
539         if (!rc && d_really_is_positive(dentry))
540                 clear_nlink(d_inode(dentry));
541         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
542         set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
543         unlock_dir(lower_dir_dentry);
544         if (!rc)
545                 d_drop(dentry);
546         dput(dentry);
547         return rc;
548 }
549
550 static int
551 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
552 {
553         int rc;
554         struct dentry *lower_dentry;
555         struct dentry *lower_dir_dentry;
556
557         lower_dentry = ecryptfs_dentry_to_lower(dentry);
558         lower_dir_dentry = lock_parent(lower_dentry);
559         rc = vfs_mknod(d_inode(lower_dir_dentry), lower_dentry, mode, dev);
560         if (rc || d_really_is_negative(lower_dentry))
561                 goto out;
562         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
563         if (rc)
564                 goto out;
565         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
566         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
567 out:
568         unlock_dir(lower_dir_dentry);
569         if (d_really_is_negative(dentry))
570                 d_drop(dentry);
571         return rc;
572 }
573
574 static int
575 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
576                 struct inode *new_dir, struct dentry *new_dentry,
577                 unsigned int flags)
578 {
579         int rc;
580         struct dentry *lower_old_dentry;
581         struct dentry *lower_new_dentry;
582         struct dentry *lower_old_dir_dentry;
583         struct dentry *lower_new_dir_dentry;
584         struct dentry *trap = NULL;
585         struct inode *target_inode;
586
587         if (flags)
588                 return -EINVAL;
589
590         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
591         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
592         dget(lower_old_dentry);
593         dget(lower_new_dentry);
594         lower_old_dir_dentry = dget_parent(lower_old_dentry);
595         lower_new_dir_dentry = dget_parent(lower_new_dentry);
596         target_inode = d_inode(new_dentry);
597         trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
598         /* source should not be ancestor of target */
599         if (trap == lower_old_dentry) {
600                 rc = -EINVAL;
601                 goto out_lock;
602         }
603         /* target should not be ancestor of source */
604         if (trap == lower_new_dentry) {
605                 rc = -ENOTEMPTY;
606                 goto out_lock;
607         }
608         rc = vfs_rename(d_inode(lower_old_dir_dentry), lower_old_dentry,
609                         d_inode(lower_new_dir_dentry), lower_new_dentry,
610                         NULL, 0);
611         if (rc)
612                 goto out_lock;
613         if (target_inode)
614                 fsstack_copy_attr_all(target_inode,
615                                       ecryptfs_inode_to_lower(target_inode));
616         fsstack_copy_attr_all(new_dir, d_inode(lower_new_dir_dentry));
617         if (new_dir != old_dir)
618                 fsstack_copy_attr_all(old_dir, d_inode(lower_old_dir_dentry));
619 out_lock:
620         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
621         dput(lower_new_dir_dentry);
622         dput(lower_old_dir_dentry);
623         dput(lower_new_dentry);
624         dput(lower_old_dentry);
625         return rc;
626 }
627
628 static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
629 {
630         DEFINE_DELAYED_CALL(done);
631         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
632         const char *link;
633         char *buf;
634         int rc;
635
636         link = vfs_get_link(lower_dentry, &done);
637         if (IS_ERR(link))
638                 return ERR_CAST(link);
639
640         rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb,
641                                                   link, strlen(link));
642         do_delayed_call(&done);
643         if (rc)
644                 return ERR_PTR(rc);
645
646         return buf;
647 }
648
649 static const char *ecryptfs_get_link(struct dentry *dentry,
650                                      struct inode *inode,
651                                      struct delayed_call *done)
652 {
653         size_t len;
654         char *buf;
655
656         if (!dentry)
657                 return ERR_PTR(-ECHILD);
658
659         buf = ecryptfs_readlink_lower(dentry, &len);
660         if (IS_ERR(buf))
661                 return buf;
662         fsstack_copy_attr_atime(d_inode(dentry),
663                                 d_inode(ecryptfs_dentry_to_lower(dentry)));
664         buf[len] = '\0';
665         set_delayed_call(done, kfree_link, buf);
666         return buf;
667 }
668
669 /**
670  * upper_size_to_lower_size
671  * @crypt_stat: Crypt_stat associated with file
672  * @upper_size: Size of the upper file
673  *
674  * Calculate the required size of the lower file based on the
675  * specified size of the upper file. This calculation is based on the
676  * number of headers in the underlying file and the extent size.
677  *
678  * Returns Calculated size of the lower file.
679  */
680 static loff_t
681 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
682                          loff_t upper_size)
683 {
684         loff_t lower_size;
685
686         lower_size = ecryptfs_lower_header_size(crypt_stat);
687         if (upper_size != 0) {
688                 loff_t num_extents;
689
690                 num_extents = upper_size >> crypt_stat->extent_shift;
691                 if (upper_size & ~crypt_stat->extent_mask)
692                         num_extents++;
693                 lower_size += (num_extents * crypt_stat->extent_size);
694         }
695         return lower_size;
696 }
697
698 /**
699  * truncate_upper
700  * @dentry: The ecryptfs layer dentry
701  * @ia: Address of the ecryptfs inode's attributes
702  * @lower_ia: Address of the lower inode's attributes
703  *
704  * Function to handle truncations modifying the size of the file. Note
705  * that the file sizes are interpolated. When expanding, we are simply
706  * writing strings of 0's out. When truncating, we truncate the upper
707  * inode and update the lower_ia according to the page index
708  * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
709  * the caller must use lower_ia in a call to notify_change() to perform
710  * the truncation of the lower inode.
711  *
712  * Returns zero on success; non-zero otherwise
713  */
714 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
715                           struct iattr *lower_ia)
716 {
717         int rc = 0;
718         struct inode *inode = d_inode(dentry);
719         struct ecryptfs_crypt_stat *crypt_stat;
720         loff_t i_size = i_size_read(inode);
721         loff_t lower_size_before_truncate;
722         loff_t lower_size_after_truncate;
723
724         if (unlikely((ia->ia_size == i_size))) {
725                 lower_ia->ia_valid &= ~ATTR_SIZE;
726                 return 0;
727         }
728         rc = ecryptfs_get_lower_file(dentry, inode);
729         if (rc)
730                 return rc;
731         crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
732         /* Switch on growing or shrinking file */
733         if (ia->ia_size > i_size) {
734                 char zero[] = { 0x00 };
735
736                 lower_ia->ia_valid &= ~ATTR_SIZE;
737                 /* Write a single 0 at the last position of the file;
738                  * this triggers code that will fill in 0's throughout
739                  * the intermediate portion of the previous end of the
740                  * file and the new and of the file */
741                 rc = ecryptfs_write(inode, zero,
742                                     (ia->ia_size - 1), 1);
743         } else { /* ia->ia_size < i_size_read(inode) */
744                 /* We're chopping off all the pages down to the page
745                  * in which ia->ia_size is located. Fill in the end of
746                  * that page from (ia->ia_size & ~PAGE_MASK) to
747                  * PAGE_SIZE with zeros. */
748                 size_t num_zeros = (PAGE_SIZE
749                                     - (ia->ia_size & ~PAGE_MASK));
750
751                 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
752                         truncate_setsize(inode, ia->ia_size);
753                         lower_ia->ia_size = ia->ia_size;
754                         lower_ia->ia_valid |= ATTR_SIZE;
755                         goto out;
756                 }
757                 if (num_zeros) {
758                         char *zeros_virt;
759
760                         zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
761                         if (!zeros_virt) {
762                                 rc = -ENOMEM;
763                                 goto out;
764                         }
765                         rc = ecryptfs_write(inode, zeros_virt,
766                                             ia->ia_size, num_zeros);
767                         kfree(zeros_virt);
768                         if (rc) {
769                                 printk(KERN_ERR "Error attempting to zero out "
770                                        "the remainder of the end page on "
771                                        "reducing truncate; rc = [%d]\n", rc);
772                                 goto out;
773                         }
774                 }
775                 truncate_setsize(inode, ia->ia_size);
776                 rc = ecryptfs_write_inode_size_to_metadata(inode);
777                 if (rc) {
778                         printk(KERN_ERR "Problem with "
779                                "ecryptfs_write_inode_size_to_metadata; "
780                                "rc = [%d]\n", rc);
781                         goto out;
782                 }
783                 /* We are reducing the size of the ecryptfs file, and need to
784                  * know if we need to reduce the size of the lower file. */
785                 lower_size_before_truncate =
786                     upper_size_to_lower_size(crypt_stat, i_size);
787                 lower_size_after_truncate =
788                     upper_size_to_lower_size(crypt_stat, ia->ia_size);
789                 if (lower_size_after_truncate < lower_size_before_truncate) {
790                         lower_ia->ia_size = lower_size_after_truncate;
791                         lower_ia->ia_valid |= ATTR_SIZE;
792                 } else
793                         lower_ia->ia_valid &= ~ATTR_SIZE;
794         }
795 out:
796         ecryptfs_put_lower_file(inode);
797         return rc;
798 }
799
800 static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset)
801 {
802         struct ecryptfs_crypt_stat *crypt_stat;
803         loff_t lower_oldsize, lower_newsize;
804
805         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
806         lower_oldsize = upper_size_to_lower_size(crypt_stat,
807                                                  i_size_read(inode));
808         lower_newsize = upper_size_to_lower_size(crypt_stat, offset);
809         if (lower_newsize > lower_oldsize) {
810                 /*
811                  * The eCryptfs inode and the new *lower* size are mixed here
812                  * because we may not have the lower i_mutex held and/or it may
813                  * not be appropriate to call inode_newsize_ok() with inodes
814                  * from other filesystems.
815                  */
816                 return inode_newsize_ok(inode, lower_newsize);
817         }
818
819         return 0;
820 }
821
822 /**
823  * ecryptfs_truncate
824  * @dentry: The ecryptfs layer dentry
825  * @new_length: The length to expand the file to
826  *
827  * Simple function that handles the truncation of an eCryptfs inode and
828  * its corresponding lower inode.
829  *
830  * Returns zero on success; non-zero otherwise
831  */
832 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
833 {
834         struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
835         struct iattr lower_ia = { .ia_valid = 0 };
836         int rc;
837
838         rc = ecryptfs_inode_newsize_ok(d_inode(dentry), new_length);
839         if (rc)
840                 return rc;
841
842         rc = truncate_upper(dentry, &ia, &lower_ia);
843         if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
844                 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
845
846                 inode_lock(d_inode(lower_dentry));
847                 rc = notify_change(lower_dentry, &lower_ia, NULL);
848                 inode_unlock(d_inode(lower_dentry));
849         }
850         return rc;
851 }
852
853 static int
854 ecryptfs_permission(struct inode *inode, int mask)
855 {
856         return inode_permission(ecryptfs_inode_to_lower(inode), mask);
857 }
858
859 /**
860  * ecryptfs_setattr
861  * @dentry: dentry handle to the inode to modify
862  * @ia: Structure with flags of what to change and values
863  *
864  * Updates the metadata of an inode. If the update is to the size
865  * i.e. truncation, then ecryptfs_truncate will handle the size modification
866  * of both the ecryptfs inode and the lower inode.
867  *
868  * All other metadata changes will be passed right to the lower filesystem,
869  * and we will just update our inode to look like the lower.
870  */
871 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
872 {
873         int rc = 0;
874         struct dentry *lower_dentry;
875         struct iattr lower_ia;
876         struct inode *inode;
877         struct inode *lower_inode;
878         struct ecryptfs_crypt_stat *crypt_stat;
879
880         crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
881         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)) {
882                 rc = ecryptfs_init_crypt_stat(crypt_stat);
883                 if (rc)
884                         return rc;
885         }
886         inode = d_inode(dentry);
887         lower_inode = ecryptfs_inode_to_lower(inode);
888         lower_dentry = ecryptfs_dentry_to_lower(dentry);
889         mutex_lock(&crypt_stat->cs_mutex);
890         if (d_is_dir(dentry))
891                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
892         else if (d_is_reg(dentry)
893                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
894                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
895                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
896
897                 mount_crypt_stat = &ecryptfs_superblock_to_private(
898                         dentry->d_sb)->mount_crypt_stat;
899                 rc = ecryptfs_get_lower_file(dentry, inode);
900                 if (rc) {
901                         mutex_unlock(&crypt_stat->cs_mutex);
902                         goto out;
903                 }
904                 rc = ecryptfs_read_metadata(dentry);
905                 ecryptfs_put_lower_file(inode);
906                 if (rc) {
907                         if (!(mount_crypt_stat->flags
908                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
909                                 rc = -EIO;
910                                 printk(KERN_WARNING "Either the lower file "
911                                        "is not in a valid eCryptfs format, "
912                                        "or the key could not be retrieved. "
913                                        "Plaintext passthrough mode is not "
914                                        "enabled; returning -EIO\n");
915                                 mutex_unlock(&crypt_stat->cs_mutex);
916                                 goto out;
917                         }
918                         rc = 0;
919                         crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
920                                                | ECRYPTFS_ENCRYPTED);
921                 }
922         }
923         mutex_unlock(&crypt_stat->cs_mutex);
924
925         rc = setattr_prepare(dentry, ia);
926         if (rc)
927                 goto out;
928         if (ia->ia_valid & ATTR_SIZE) {
929                 rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size);
930                 if (rc)
931                         goto out;
932         }
933
934         memcpy(&lower_ia, ia, sizeof(lower_ia));
935         if (ia->ia_valid & ATTR_FILE)
936                 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
937         if (ia->ia_valid & ATTR_SIZE) {
938                 rc = truncate_upper(dentry, ia, &lower_ia);
939                 if (rc < 0)
940                         goto out;
941         }
942
943         /*
944          * mode change is for clearing setuid/setgid bits. Allow lower fs
945          * to interpret this in its own way.
946          */
947         if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
948                 lower_ia.ia_valid &= ~ATTR_MODE;
949
950         inode_lock(d_inode(lower_dentry));
951         rc = notify_change(lower_dentry, &lower_ia, NULL);
952         inode_unlock(d_inode(lower_dentry));
953 out:
954         fsstack_copy_attr_all(inode, lower_inode);
955         return rc;
956 }
957
958 static int ecryptfs_getattr_link(const struct path *path, struct kstat *stat,
959                                  u32 request_mask, unsigned int flags)
960 {
961         struct dentry *dentry = path->dentry;
962         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
963         int rc = 0;
964
965         mount_crypt_stat = &ecryptfs_superblock_to_private(
966                                                 dentry->d_sb)->mount_crypt_stat;
967         generic_fillattr(d_inode(dentry), stat);
968         if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
969                 char *target;
970                 size_t targetsiz;
971
972                 target = ecryptfs_readlink_lower(dentry, &targetsiz);
973                 if (!IS_ERR(target)) {
974                         kfree(target);
975                         stat->size = targetsiz;
976                 } else {
977                         rc = PTR_ERR(target);
978                 }
979         }
980         return rc;
981 }
982
983 static int ecryptfs_getattr(const struct path *path, struct kstat *stat,
984                             u32 request_mask, unsigned int flags)
985 {
986         struct dentry *dentry = path->dentry;
987         struct kstat lower_stat;
988         int rc;
989
990         rc = vfs_getattr(ecryptfs_dentry_to_lower_path(dentry), &lower_stat,
991                          request_mask, flags);
992         if (!rc) {
993                 fsstack_copy_attr_all(d_inode(dentry),
994                                       ecryptfs_inode_to_lower(d_inode(dentry)));
995                 generic_fillattr(d_inode(dentry), stat);
996                 stat->blocks = lower_stat.blocks;
997         }
998         return rc;
999 }
1000
1001 int
1002 ecryptfs_setxattr(struct dentry *dentry, struct inode *inode,
1003                   const char *name, const void *value,
1004                   size_t size, int flags)
1005 {
1006         int rc;
1007         struct dentry *lower_dentry;
1008
1009         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1010         if (!(d_inode(lower_dentry)->i_opflags & IOP_XATTR)) {
1011                 rc = -EOPNOTSUPP;
1012                 goto out;
1013         }
1014         rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1015         if (!rc && inode)
1016                 fsstack_copy_attr_all(inode, d_inode(lower_dentry));
1017 out:
1018         return rc;
1019 }
1020
1021 ssize_t
1022 ecryptfs_getxattr_lower(struct dentry *lower_dentry, struct inode *lower_inode,
1023                         const char *name, void *value, size_t size)
1024 {
1025         int rc;
1026
1027         if (!(lower_inode->i_opflags & IOP_XATTR)) {
1028                 rc = -EOPNOTSUPP;
1029                 goto out;
1030         }
1031         inode_lock(lower_inode);
1032         rc = __vfs_getxattr(lower_dentry, lower_inode, name, value, size);
1033         inode_unlock(lower_inode);
1034 out:
1035         return rc;
1036 }
1037
1038 static ssize_t
1039 ecryptfs_getxattr(struct dentry *dentry, struct inode *inode,
1040                   const char *name, void *value, size_t size)
1041 {
1042         return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
1043                                        ecryptfs_inode_to_lower(inode),
1044                                        name, value, size);
1045 }
1046
1047 static ssize_t
1048 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1049 {
1050         int rc = 0;
1051         struct dentry *lower_dentry;
1052
1053         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1054         if (!d_inode(lower_dentry)->i_op->listxattr) {
1055                 rc = -EOPNOTSUPP;
1056                 goto out;
1057         }
1058         inode_lock(d_inode(lower_dentry));
1059         rc = d_inode(lower_dentry)->i_op->listxattr(lower_dentry, list, size);
1060         inode_unlock(d_inode(lower_dentry));
1061 out:
1062         return rc;
1063 }
1064
1065 static int ecryptfs_removexattr(struct dentry *dentry, struct inode *inode,
1066                                 const char *name)
1067 {
1068         int rc;
1069         struct dentry *lower_dentry;
1070         struct inode *lower_inode;
1071
1072         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1073         lower_inode = ecryptfs_inode_to_lower(inode);
1074         if (!(lower_inode->i_opflags & IOP_XATTR)) {
1075                 rc = -EOPNOTSUPP;
1076                 goto out;
1077         }
1078         inode_lock(lower_inode);
1079         rc = __vfs_removexattr(lower_dentry, name);
1080         inode_unlock(lower_inode);
1081 out:
1082         return rc;
1083 }
1084
1085 const struct inode_operations ecryptfs_symlink_iops = {
1086         .get_link = ecryptfs_get_link,
1087         .permission = ecryptfs_permission,
1088         .setattr = ecryptfs_setattr,
1089         .getattr = ecryptfs_getattr_link,
1090         .listxattr = ecryptfs_listxattr,
1091 };
1092
1093 const struct inode_operations ecryptfs_dir_iops = {
1094         .create = ecryptfs_create,
1095         .lookup = ecryptfs_lookup,
1096         .link = ecryptfs_link,
1097         .unlink = ecryptfs_unlink,
1098         .symlink = ecryptfs_symlink,
1099         .mkdir = ecryptfs_mkdir,
1100         .rmdir = ecryptfs_rmdir,
1101         .mknod = ecryptfs_mknod,
1102         .rename = ecryptfs_rename,
1103         .permission = ecryptfs_permission,
1104         .setattr = ecryptfs_setattr,
1105         .listxattr = ecryptfs_listxattr,
1106 };
1107
1108 const struct inode_operations ecryptfs_main_iops = {
1109         .permission = ecryptfs_permission,
1110         .setattr = ecryptfs_setattr,
1111         .getattr = ecryptfs_getattr,
1112         .listxattr = ecryptfs_listxattr,
1113 };
1114
1115 static int ecryptfs_xattr_get(const struct xattr_handler *handler,
1116                               struct dentry *dentry, struct inode *inode,
1117                               const char *name, void *buffer, size_t size)
1118 {
1119         return ecryptfs_getxattr(dentry, inode, name, buffer, size);
1120 }
1121
1122 static int ecryptfs_xattr_set(const struct xattr_handler *handler,
1123                               struct dentry *dentry, struct inode *inode,
1124                               const char *name, const void *value, size_t size,
1125                               int flags)
1126 {
1127         if (value)
1128                 return ecryptfs_setxattr(dentry, inode, name, value, size, flags);
1129         else {
1130                 BUG_ON(flags != XATTR_REPLACE);
1131                 return ecryptfs_removexattr(dentry, inode, name);
1132         }
1133 }
1134
1135 const struct xattr_handler ecryptfs_xattr_handler = {
1136         .prefix = "",  /* match anything */
1137         .get = ecryptfs_xattr_get,
1138         .set = ecryptfs_xattr_set,
1139 };
1140
1141 const struct xattr_handler *ecryptfs_xattr_handlers[] = {
1142         &ecryptfs_xattr_handler,
1143         NULL
1144 };